blender-archive/source/blender/blenloader/intern/readfile.c

/*
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * The Original Code is Copyright (C) 2001-2002 by NaN Holding BV.
 * All rights reserved.
 */

/** \file
 * \ingroup blenloader
 */

#include "zlib.h"

#include <limits.h>
#include <stdio.h>   // for printf fopen fwrite fclose sprintf FILE
#include <stdlib.h>  // for getenv atoi
#include <stddef.h>  // for offsetof
#include <fcntl.h>   // for open
#include <string.h>  // for strrchr strncmp strstr
#include <math.h>    // for fabs
#include <stdarg.h>  /* for va_start/end */
#include <time.h>    /* for gmtime */
#include <ctype.h>   /* for isdigit */

#include "BLI_utildefines.h"
#ifndef WIN32
#  include <unistd.h>  // for read close
#else
#  include <io.h>  // for open close read
#  include "winsock2.h"
#  include "BLI_winstuff.h"
#endif

/* allow readfile to use deprecated functionality */
#define DNA_DEPRECATED_ALLOW

#include "DNA_anim_types.h"
#include "DNA_armature_types.h"
#include "DNA_brush_types.h"
#include "DNA_camera_types.h"
#include "DNA_cachefile_types.h"
#include "DNA_cloth_types.h"
#include "DNA_collection_types.h"
#include "DNA_constraint_types.h"
#include "DNA_dynamicpaint_types.h"
#include "DNA_effect_types.h"
#include "DNA_fileglobal_types.h"
#include "DNA_genfile.h"
#include "DNA_gpencil_types.h"
#include "DNA_gpencil_modifier_types.h"
#include "DNA_shader_fx_types.h"
#include "DNA_ipo_types.h"
#include "DNA_key_types.h"
#include "DNA_lattice_types.h"
#include "DNA_layer_types.h"
#include "DNA_light_types.h"
#include "DNA_linestyle_types.h"
#include "DNA_meta_types.h"
#include "DNA_material_types.h"
#include "DNA_mesh_types.h"
#include "DNA_meshdata_types.h"
#include "DNA_nla_types.h"
#include "DNA_node_types.h"
#include "DNA_object_fluidsim_types.h"
#include "DNA_object_types.h"
#include "DNA_packedFile_types.h"
#include "DNA_particle_types.h"
#include "DNA_lightprobe_types.h"
#include "DNA_rigidbody_types.h"
#include "DNA_text_types.h"
#include "DNA_view3d_types.h"
#include "DNA_screen_types.h"
#include "DNA_sdna_types.h"
#include "DNA_scene_types.h"
#include "DNA_sequence_types.h"
#include "DNA_smoke_types.h"
#include "DNA_speaker_types.h"
#include "DNA_sound_types.h"
#include "DNA_space_types.h"
#include "DNA_vfont_types.h"
#include "DNA_workspace_types.h"
#include "DNA_world_types.h"
#include "DNA_movieclip_types.h"
#include "DNA_mask_types.h"

#include "RNA_access.h"

#include "MEM_guardedalloc.h"

#include "BLI_endian_switch.h"
#include "BLI_blenlib.h"
#include "BLI_math.h"
#include "BLI_threads.h"
#include "BLI_mempool.h"
#include "BLI_ghash.h"

#include "BLT_translation.h"

#include "BKE_action.h"
#include "BKE_armature.h"
#include "BKE_brush.h"
#include "BKE_cachefile.h"
#include "BKE_cloth.h"
#include "BKE_collection.h"
#include "BKE_colortools.h"
#include "BKE_constraint.h"
#include "BKE_curve.h"
#include "BKE_effect.h"
#include "BKE_fcurve.h"
#include "BKE_global.h"  // for G
#include "BKE_gpencil.h"
#include "BKE_gpencil_modifier.h"
#include "BKE_idcode.h"
#include "BKE_idprop.h"
#include "BKE_layer.h"
#include "BKE_library.h"
#include "BKE_library_idmap.h"
#include "BKE_library_override.h"
#include "BKE_library_query.h"
#include "BKE_main.h"  // for Main
#include "BKE_material.h"
#include "BKE_mesh.h"  // for ME_ defines (patching)
#include "BKE_mesh_runtime.h"
#include "BKE_modifier.h"
#include "BKE_multires.h"
#include "BKE_node.h"  // for tree type defines
#include "BKE_object.h"
#include "BKE_ocean.h"
#include "BKE_outliner_treehash.h"
#include "BKE_paint.h"
#include "BKE_particle.h"
#include "BKE_pointcache.h"
#include "BKE_report.h"
#include "BKE_scene.h"
#include "BKE_screen.h"
#include "BKE_sequencer.h"
#include "BKE_shader_fx.h"
#include "BKE_sound.h"
#include "BKE_workspace.h"

#include "DRW_engine.h"

#include "DEG_depsgraph.h"

#include "NOD_socket.h"

#include "BLO_blend_defs.h"
#include "BLO_blend_validate.h"
#include "BLO_readfile.h"
#include "BLO_undofile.h"

#include "RE_engine.h"

#include "readfile.h"

#include <errno.h>

/**
 * READ
 * ====
 *
 * - Existing Library (#Main) push or free
 * - allocate new #Main
 * - load file
 * - read #SDNA
 * - for each LibBlock
 *   - read LibBlock
 *   - if a Library
 *     - make a new #Main
 *     - attach ID's to it
 *   - else
 *     - read associated 'direct data'
 *     - link direct data (internal and to LibBlock)
 * - read #FileGlobal
 * - read #USER data, only when indicated (file is ``~/X.XX/startup.blend``)
 * - free file
 * - per Library (per #Main)
 *   - read file
 *   - read #SDNA
 *   - find LibBlocks and attach #ID's to #Main
 *     - if external LibBlock
 *       - search all #Main's
 *         - or it's already read,
 *         - or not read yet
 *         - or make new #Main
 *   - per LibBlock
 *     - read recursive
 *     - read associated direct data
 *     - link direct data (internal and to LibBlock)
 *   - free file
 * - per Library with unread LibBlocks
 *   - read file
 *   - read #SDNA
 *   - per LibBlock
 *     - read recursive
 *     - read associated direct data
 *     - link direct data (internal and to LibBlock)
 *   - free file
 * - join all #Main's
 * - link all LibBlocks and indirect pointers to libblocks
 * - initialize #FileGlobal and copy pointers to #Global
 *
 * \note Still a weak point is the new-address function, that doesn't solve reading from
 * multiple files at the same time.
 * (added remark: oh, i thought that was solved? will look at that... (ton).
 */

/**
 * Delay reading blocks we might not use (especially applies to library linking).
 * which keeps large arrays in memory from data-blocks we may not even use.
 *
 * \note This is disabled when using compression,
 * while zlib supports seek ist's unusably slow, see: T61880.
 */
#define USE_BHEAD_READ_ON_DEMAND

/* use GHash for BHead name-based lookups (speeds up linking) */
#define USE_GHASH_BHEAD

/* Use GHash for restoring pointers by name */
#define USE_GHASH_RESTORE_POINTER

/* Define this to have verbose debug prints. */
#define USE_DEBUG_PRINT

#ifdef USE_DEBUG_PRINT
#  define DEBUG_PRINTF(...) printf(__VA_ARGS__)
#else
#  define DEBUG_PRINTF(...)
#endif

/* local prototypes */
static void read_libraries(FileData *basefd, ListBase *mainlist);
static void *read_struct(FileData *fd, BHead *bh, const char *blockname);
static void direct_link_modifiers(FileData *fd, ListBase *lb);
static BHead *find_bhead_from_code_name(FileData *fd, const short idcode, const char *name);
static BHead *find_bhead_from_idname(FileData *fd, const char *idname);

#ifdef USE_COLLECTION_COMPAT_28
static void expand_scene_collection(FileData *fd, Main *mainvar, SceneCollection *sc);
#endif
static void direct_link_animdata(FileData *fd, AnimData *adt);
static void lib_link_animdata(FileData *fd, ID *id, AnimData *adt);

typedef struct BHeadN {
  struct BHeadN *next, *prev;
#ifdef USE_BHEAD_READ_ON_DEMAND
  /** Use to read the data from the file directly into memory as needed. */
  off64_t file_offset;
  /** When set, the remainder of this allocation is the data, otherwise it needs to be read. */
  bool has_data;
#endif
  struct BHead bhead;
} BHeadN;

#define BHEADN_FROM_BHEAD(bh) ((BHeadN *)POINTER_OFFSET(bh, -offsetof(BHeadN, bhead)))

/* We could change this in the future, for now it's simplest if only data is delayed
 * because ID names are used in lookup tables. */
#define BHEAD_USE_READ_ON_DEMAND(bhead) ((bhead)->code == DATA)

/* this function ensures that reports are printed,
 * in the case of libraray linking errors this is important!
 *
 * bit kludge but better then doubling up on prints,
 * we could alternatively have a versions of a report function which forces printing - campbell
 */

void blo_reportf_wrap(ReportList *reports, ReportType type, const char *format, ...)
{
  char fixed_buf[1024]; /* should be long enough */

  va_list args;

  va_start(args, format);
  vsnprintf(fixed_buf, sizeof(fixed_buf), format, args);
  va_end(args);

  fixed_buf[sizeof(fixed_buf) - 1] = '\0';

  BKE_report(reports, type, fixed_buf);

  if (G.background == 0) {
    printf("%s: %s\n", BKE_report_type_str(type), fixed_buf);
  }
}

/* for reporting linking messages */
static const char *library_parent_filepath(Library *lib)
{
  return lib->parent ? lib->parent->filepath : "<direct>";
}

/* -------------------------------------------------------------------- */
/** \name OldNewMap API
 * \{ */

typedef struct OldNew {
  const void *oldp;
  void *newp;
  /* `nr` is "user count" for data, and ID code for libdata. */
  int nr;
} OldNew;

typedef struct OldNewMap {
  /* Array that stores the actual entries. */
  OldNew *entries;
  int nentries;
  /* Hashmap that stores indices into the `entries` array. */
  int32_t *map;

  int capacity_exp;
} OldNewMap;

#define ENTRIES_CAPACITY(onm) (1ll << (onm)->capacity_exp)
#define MAP_CAPACITY(onm) (1ll << ((onm)->capacity_exp + 1))
#define SLOT_MASK(onm) (MAP_CAPACITY(onm) - 1)
#define DEFAULT_SIZE_EXP 6
#define PERTURB_SHIFT 5

/* based on the probing algorithm used in Python dicts. */
#define ITER_SLOTS(onm, KEY, SLOT_NAME, INDEX_NAME) \
  uint32_t hash = BLI_ghashutil_ptrhash(KEY); \
  uint32_t mask = SLOT_MASK(onm); \
  uint perturb = hash; \
  int SLOT_NAME = mask & hash; \
  int INDEX_NAME = onm->map[SLOT_NAME]; \
  for (;; SLOT_NAME = mask & ((5 * SLOT_NAME) + 1 + perturb), \
          perturb >>= PERTURB_SHIFT, \
          INDEX_NAME = onm->map[SLOT_NAME])

static void oldnewmap_insert_index_in_map(OldNewMap *onm, const void *ptr, int index)
{
  ITER_SLOTS (onm, ptr, slot, stored_index) {
    if (stored_index == -1) {
      onm->map[slot] = index;
      break;
    }
  }
}

static void oldnewmap_insert_or_replace(OldNewMap *onm, OldNew entry)
{
  ITER_SLOTS (onm, entry.oldp, slot, index) {
    if (index == -1) {
      onm->entries[onm->nentries] = entry;
      onm->map[slot] = onm->nentries;
      onm->nentries++;
      break;
    }
    else if (onm->entries[index].oldp == entry.oldp) {
      onm->entries[index] = entry;
      break;
    }
  }
}

static OldNew *oldnewmap_lookup_entry(const OldNewMap *onm, const void *addr)
{
  ITER_SLOTS (onm, addr, slot, index) {
    if (index >= 0) {
      OldNew *entry = &onm->entries[index];
      if (entry->oldp == addr) {
        return entry;
      }
    }
    else {
      return NULL;
    }
  }
}

static void oldnewmap_clear_map(OldNewMap *onm)
{
  memset(onm->map, 0xFF, MAP_CAPACITY(onm) * sizeof(*onm->map));
}

static void oldnewmap_increase_size(OldNewMap *onm)
{
  onm->capacity_exp++;
  onm->entries = MEM_reallocN(onm->entries, sizeof(*onm->entries) * ENTRIES_CAPACITY(onm));
  onm->map = MEM_reallocN(onm->map, sizeof(*onm->map) * MAP_CAPACITY(onm));
  oldnewmap_clear_map(onm);
  for (int i = 0; i < onm->nentries; i++) {
    oldnewmap_insert_index_in_map(onm, onm->entries[i].oldp, i);
  }
}

/* Public OldNewMap API */

static OldNewMap *oldnewmap_new(void)
{
  OldNewMap *onm = MEM_callocN(sizeof(*onm), "OldNewMap");

  onm->capacity_exp = DEFAULT_SIZE_EXP;
  onm->entries = MEM_malloc_arrayN(
      ENTRIES_CAPACITY(onm), sizeof(*onm->entries), "OldNewMap.entries");
  onm->map = MEM_malloc_arrayN(MAP_CAPACITY(onm), sizeof(*onm->map), "OldNewMap.map");
  oldnewmap_clear_map(onm);

  return onm;
}

static void oldnewmap_insert(OldNewMap *onm, const void *oldaddr, void *newaddr, int nr)
{
  if (oldaddr == NULL || newaddr == NULL) {
    return;
  }

  if (UNLIKELY(onm->nentries == ENTRIES_CAPACITY(onm))) {
    oldnewmap_increase_size(onm);
  }

  OldNew entry;
  entry.oldp = oldaddr;
  entry.newp = newaddr;
  entry.nr = nr;
  oldnewmap_insert_or_replace(onm, entry);
}

void blo_do_versions_oldnewmap_insert(OldNewMap *onm, const void *oldaddr, void *newaddr, int nr)
{
  oldnewmap_insert(onm, oldaddr, newaddr, nr);
}

static void *oldnewmap_lookup_and_inc(OldNewMap *onm, const void *addr, bool increase_users)
{
  OldNew *entry = oldnewmap_lookup_entry(onm, addr);
  if (entry == NULL) {
    return NULL;
  }
  if (increase_users) {
    entry->nr++;
  }
  return entry->newp;
}

/* for libdata, OldNew.nr has ID code, no increment */
static void *oldnewmap_liblookup(OldNewMap *onm, const void *addr, const void *lib)
{
  if (addr == NULL) {
    return NULL;
  }

  ID *id = oldnewmap_lookup_and_inc(onm, addr, false);
  if (id == NULL) {
    return NULL;
  }
  if (!lib || id->lib) {
    return id;
  }
  return NULL;
}

static void oldnewmap_free_unused(OldNewMap *onm)
{
  for (int i = 0; i < onm->nentries; i++) {
    OldNew *entry = &onm->entries[i];
    if (entry->nr == 0) {
      MEM_freeN(entry->newp);
      entry->newp = NULL;
    }
  }
}

static void oldnewmap_clear(OldNewMap *onm)
{
  onm->capacity_exp = DEFAULT_SIZE_EXP;
  oldnewmap_clear_map(onm);
  onm->nentries = 0;
}

static void oldnewmap_free(OldNewMap *onm)
{
  MEM_freeN(onm->entries);
  MEM_freeN(onm->map);
  MEM_freeN(onm);
}

#undef ENTRIES_CAPACITY
#undef MAP_CAPACITY
#undef SLOT_MASK
#undef DEFAULT_SIZE_EXP
#undef PERTURB_SHIFT
#undef ITER_SLOTS

/** \} */

/* -------------------------------------------------------------------- */
/** \name Helper Functions
 * \{ */

static void add_main_to_main(Main *mainvar, Main *from)
{
  ListBase *lbarray[MAX_LIBARRAY], *fromarray[MAX_LIBARRAY];
  int a;

  set_listbasepointers(mainvar, lbarray);
  a = set_listbasepointers(from, fromarray);
  while (a--) {
    BLI_movelisttolist(lbarray[a], fromarray[a]);
  }
}

void blo_join_main(ListBase *mainlist)
{
  Main *tojoin, *mainl;

  mainl = mainlist->first;
  while ((tojoin = mainl->next)) {
    add_main_to_main(mainl, tojoin);
    BLI_remlink(mainlist, tojoin);
    BKE_main_free(tojoin);
  }
}

static void split_libdata(ListBase *lb_src, Main **lib_main_array, const uint lib_main_array_len)
{
  for (ID *id = lb_src->first, *idnext; id; id = idnext) {
    idnext = id->next;

    if (id->lib) {
      if (((uint)id->lib->temp_index < lib_main_array_len) &&
          /* this check should never fail, just incase 'id->lib' is a dangling pointer. */
          (lib_main_array[id->lib->temp_index]->curlib == id->lib)) {
        Main *mainvar = lib_main_array[id->lib->temp_index];
        ListBase *lb_dst = which_libbase(mainvar, GS(id->name));
        BLI_remlink(lb_src, id);
        BLI_addtail(lb_dst, id);
      }
      else {
        printf("%s: invalid library for '%s'\n", __func__, id->name);
        BLI_assert(0);
      }
    }
  }
}

void blo_split_main(ListBase *mainlist, Main *main)
{
  mainlist->first = mainlist->last = main;
  main->next = NULL;

  if (BLI_listbase_is_empty(&main->libraries)) {
    return;
  }

  /* (Library.temp_index -> Main), lookup table */
  const uint lib_main_array_len = BLI_listbase_count(&main->libraries);
  Main **lib_main_array = MEM_malloc_arrayN(lib_main_array_len, sizeof(*lib_main_array), __func__);

  int i = 0;
  for (Library *lib = main->libraries.first; lib; lib = lib->id.next, i++) {
    Main *libmain = BKE_main_new();
    libmain->curlib = lib;
    libmain->versionfile = lib->versionfile;
    libmain->subversionfile = lib->subversionfile;
    BLI_addtail(mainlist, libmain);
    lib->temp_index = i;
    lib_main_array[i] = libmain;
  }

  ListBase *lbarray[MAX_LIBARRAY];
  i = set_listbasepointers(main, lbarray);
  while (i--) {
    ID *id = lbarray[i]->first;
    if (id == NULL || GS(id->name) == ID_LI) {
      /* No ID_LI data-lock should ever be linked anyway, but just in case, better be explicit. */
      continue;
    }
    split_libdata(lbarray[i], lib_main_array, lib_main_array_len);
  }

  MEM_freeN(lib_main_array);
}

static void read_file_version(FileData *fd, Main *main)
{
  BHead *bhead;

  for (bhead = blo_bhead_first(fd); bhead; bhead = blo_bhead_next(fd, bhead)) {
    if (bhead->code == GLOB) {
      FileGlobal *fg = read_struct(fd, bhead, "Global");
      if (fg) {
        main->subversionfile = fg->subversion;
        main->minversionfile = fg->minversion;
        main->minsubversionfile = fg->minsubversion;
        MEM_freeN(fg);
      }
      else if (bhead->code == ENDB) {
        break;
      }
    }
  }
  if (main->curlib) {
    main->curlib->versionfile = main->versionfile;
    main->curlib->subversionfile = main->subversionfile;
  }
}

#ifdef USE_GHASH_BHEAD
static void read_file_bhead_idname_map_create(FileData *fd)
{
  BHead *bhead;

  /* dummy values */
  bool is_link = false;
  int code_prev = ENDB;
  uint reserve = 0;

  for (bhead = blo_bhead_first(fd); bhead; bhead = blo_bhead_next(fd, bhead)) {
    if (code_prev != bhead->code) {
      code_prev = bhead->code;
      is_link = BKE_idcode_is_valid(code_prev) ? BKE_idcode_is_linkable(code_prev) : false;
    }

    if (is_link) {
      reserve += 1;
    }
  }

  BLI_assert(fd->bhead_idname_hash == NULL);

  fd->bhead_idname_hash = BLI_ghash_str_new_ex(__func__, reserve);

  for (bhead = blo_bhead_first(fd); bhead; bhead = blo_bhead_next(fd, bhead)) {
    if (code_prev != bhead->code) {
      code_prev = bhead->code;
      is_link = BKE_idcode_is_valid(code_prev) ? BKE_idcode_is_linkable(code_prev) : false;
    }

    if (is_link) {
      BLI_ghash_insert(fd->bhead_idname_hash, (void *)blo_bhead_id_name(fd, bhead), bhead);
    }
  }
}
#endif

static Main *blo_find_main(FileData *fd, const char *filepath, const char *relabase)
{
  ListBase *mainlist = fd->mainlist;
  Main *m;
  Library *lib;
  char name1[FILE_MAX];

  BLI_strncpy(name1, filepath, sizeof(name1));
  BLI_cleanup_path(relabase, name1);

  //  printf("blo_find_main: relabase  %s\n", relabase);
  //  printf("blo_find_main: original in  %s\n", filepath);
  //  printf("blo_find_main: converted to %s\n", name1);

  for (m = mainlist->first; m; m = m->next) {
    const char *libname = (m->curlib) ? m->curlib->filepath : m->name;

    if (BLI_path_cmp(name1, libname) == 0) {
      if (G.debug & G_DEBUG) {
        printf("blo_find_main: found library %s\n", libname);
      }
      return m;
    }
  }

  m = BKE_main_new();
  BLI_addtail(mainlist, m);

  /* Add library data-block itself to 'main' Main, since libraries are **never** linked data.
   * Fixes bug where you could end with all ID_LI data-blocks having the same name... */
  lib = BKE_libblock_alloc(mainlist->first, ID_LI, BLI_path_basename(filepath), 0);
  lib->id.us = ID_FAKE_USERS(
      lib); /* Important, consistency with main ID reading code from read_libblock(). */
  BLI_strncpy(lib->name, filepath, sizeof(lib->name));
  BLI_strncpy(lib->filepath, name1, sizeof(lib->filepath));

  m->curlib = lib;

  read_file_version(fd, m);

  if (G.debug & G_DEBUG) {
    printf("blo_find_main: added new lib %s\n", filepath);
  }
  return m;
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name File Parsing
 * \{ */

static void switch_endian_bh4(BHead4 *bhead)
{
  /* the ID_.. codes */
  if ((bhead->code & 0xFFFF) == 0) {
    bhead->code >>= 16;
  }

  if (bhead->code != ENDB) {
    BLI_endian_switch_int32(&bhead->len);
    BLI_endian_switch_int32(&bhead->SDNAnr);
    BLI_endian_switch_int32(&bhead->nr);
  }
}

static void switch_endian_bh8(BHead8 *bhead)
{
  /* the ID_.. codes */
  if ((bhead->code & 0xFFFF) == 0) {
    bhead->code >>= 16;
  }

  if (bhead->code != ENDB) {
    BLI_endian_switch_int32(&bhead->len);
    BLI_endian_switch_int32(&bhead->SDNAnr);
    BLI_endian_switch_int32(&bhead->nr);
  }
}

static void bh4_from_bh8(BHead *bhead, BHead8 *bhead8, int do_endian_swap)
{
  BHead4 *bhead4 = (BHead4 *)bhead;
  int64_t old;

  bhead4->code = bhead8->code;
  bhead4->len = bhead8->len;

  if (bhead4->code != ENDB) {
    /* perform a endian swap on 64bit pointers, otherwise the pointer might map to zero
     * 0x0000000000000000000012345678 would become 0x12345678000000000000000000000000
     */
    if (do_endian_swap) {
      BLI_endian_switch_int64(&bhead8->old);
    }

    /* this patch is to avoid a long long being read from not-eight aligned positions
     * is necessary on any modern 64bit architecture) */
    memcpy(&old, &bhead8->old, 8);
    bhead4->old = (int)(old >> 3);

    bhead4->SDNAnr = bhead8->SDNAnr;
    bhead4->nr = bhead8->nr;
  }
}

static void bh8_from_bh4(BHead *bhead, BHead4 *bhead4)
{
  BHead8 *bhead8 = (BHead8 *)bhead;

  bhead8->code = bhead4->code;
  bhead8->len = bhead4->len;

  if (bhead8->code != ENDB) {
    bhead8->old = bhead4->old;
    bhead8->SDNAnr = bhead4->SDNAnr;
    bhead8->nr = bhead4->nr;
  }
}

static BHeadN *get_bhead(FileData *fd)
{
  BHeadN *new_bhead = NULL;
  int readsize;

  if (fd) {
    if (!fd->is_eof) {
      /* initializing to zero isn't strictly needed but shuts valgrind up
       * since uninitialized memory gets compared */
      BHead8 bhead8 = {0};
      BHead4 bhead4 = {0};
      BHead bhead = {0};

      /* First read the bhead structure.
       * Depending on the platform the file was written on this can
       * be a big or little endian BHead4 or BHead8 structure.
       *
       * As usual 'ENDB' (the last *partial* bhead of the file)
       * needs some special handling. We don't want to EOF just yet.
       */
      if (fd->flags & FD_FLAGS_FILE_POINTSIZE_IS_4) {
        bhead4.code = DATA;
        readsize = fd->read(fd, &bhead4, sizeof(bhead4));

        if (readsize == sizeof(bhead4) || bhead4.code == ENDB) {
          if (fd->flags & FD_FLAGS_SWITCH_ENDIAN) {
            switch_endian_bh4(&bhead4);
          }

          if (fd->flags & FD_FLAGS_POINTSIZE_DIFFERS) {
            bh8_from_bh4(&bhead, &bhead4);
          }
          else {
            /* MIN2 is only to quiet '-Warray-bounds' compiler warning. */
            BLI_assert(sizeof(bhead) == sizeof(bhead4));
            memcpy(&bhead, &bhead4, MIN2(sizeof(bhead), sizeof(bhead4)));
          }
        }
        else {
          fd->is_eof = true;
          bhead.len = 0;
        }
      }
      else {
        bhead8.code = DATA;
        readsize = fd->read(fd, &bhead8, sizeof(bhead8));

        if (readsize == sizeof(bhead8) || bhead8.code == ENDB) {
          if (fd->flags & FD_FLAGS_SWITCH_ENDIAN) {
            switch_endian_bh8(&bhead8);
          }

          if (fd->flags & FD_FLAGS_POINTSIZE_DIFFERS) {
            bh4_from_bh8(&bhead, &bhead8, (fd->flags & FD_FLAGS_SWITCH_ENDIAN));
          }
          else {
            /* MIN2 is only to quiet '-Warray-bounds' compiler warning. */
            BLI_assert(sizeof(bhead) == sizeof(bhead8));
            memcpy(&bhead, &bhead8, MIN2(sizeof(bhead), sizeof(bhead8)));
          }
        }
        else {
          fd->is_eof = true;
          bhead.len = 0;
        }
      }

      /* make sure people are not trying to pass bad blend files */
      if (bhead.len < 0) {
        fd->is_eof = true;
      }

      /* bhead now contains the (converted) bhead structure. Now read
       * the associated data and put everything in a BHeadN (creative naming !)
       */
      if (fd->is_eof) {
        /* pass */
      }
#ifdef USE_BHEAD_READ_ON_DEMAND
      else if (fd->seek != NULL && BHEAD_USE_READ_ON_DEMAND(&bhead)) {
        /* Delay reading bhead content. */
        new_bhead = MEM_mallocN(sizeof(BHeadN), "new_bhead");
        if (new_bhead) {
          new_bhead->next = new_bhead->prev = NULL;
          new_bhead->file_offset = fd->file_offset;
          new_bhead->has_data = false;
          new_bhead->bhead = bhead;
          off64_t seek_new = fd->seek(fd, bhead.len, SEEK_CUR);
          if (seek_new == -1) {
            fd->is_eof = true;
            MEM_freeN(new_bhead);
            new_bhead = NULL;
          }
          BLI_assert(fd->file_offset == seek_new);
        }
        else {
          fd->is_eof = true;
        }
      }
#endif
      else {
        new_bhead = MEM_mallocN(sizeof(BHeadN) + bhead.len, "new_bhead");
        if (new_bhead) {
          new_bhead->next = new_bhead->prev = NULL;
#ifdef USE_BHEAD_READ_ON_DEMAND
          new_bhead->file_offset = 0; /* don't seek. */
          new_bhead->has_data = true;
#endif
          new_bhead->bhead = bhead;

          readsize = fd->read(fd, new_bhead + 1, bhead.len);

          if (readsize != bhead.len) {
            fd->is_eof = true;
            MEM_freeN(new_bhead);
            new_bhead = NULL;
          }
        }
        else {
          fd->is_eof = true;
        }
      }
    }
  }

  /* We've read a new block. Now add it to the list
   * of blocks.
   */
  if (new_bhead) {
    BLI_addtail(&fd->bhead_list, new_bhead);
  }

  return new_bhead;
}

BHead *blo_bhead_first(FileData *fd)
{
  BHeadN *new_bhead;
  BHead *bhead = NULL;

  /* Rewind the file
   * Read in a new block if necessary
   */
  new_bhead = fd->bhead_list.first;
  if (new_bhead == NULL) {
    new_bhead = get_bhead(fd);
  }

  if (new_bhead) {
    bhead = &new_bhead->bhead;
  }

  return bhead;
}

BHead *blo_bhead_prev(FileData *UNUSED(fd), BHead *thisblock)
{
  BHeadN *bheadn = BHEADN_FROM_BHEAD(thisblock);
  BHeadN *prev = bheadn->prev;

  return (prev) ? &prev->bhead : NULL;
}

BHead *blo_bhead_next(FileData *fd, BHead *thisblock)
{
  BHeadN *new_bhead = NULL;
  BHead *bhead = NULL;

  if (thisblock) {
    /* bhead is actually a sub part of BHeadN
     * We calculate the BHeadN pointer from the BHead pointer below */
    new_bhead = BHEADN_FROM_BHEAD(thisblock);

    /* get the next BHeadN. If it doesn't exist we read in the next one */
    new_bhead = new_bhead->next;
    if (new_bhead == NULL) {
      new_bhead = get_bhead(fd);
    }
  }

  if (new_bhead) {
    /* here we do the reverse:
     * go from the BHeadN pointer to the BHead pointer */
    bhead = &new_bhead->bhead;
  }

  return bhead;
}

#ifdef USE_BHEAD_READ_ON_DEMAND
static bool blo_bhead_read_data(FileData *fd, BHead *thisblock, void *buf)
{
  bool success = true;
  BHeadN *new_bhead = BHEADN_FROM_BHEAD(thisblock);
  BLI_assert(new_bhead->has_data == false && new_bhead->file_offset != 0);
  off64_t offset_backup = fd->file_offset;
  if (UNLIKELY(fd->seek(fd, new_bhead->file_offset, SEEK_SET) == -1)) {
    success = false;
  }
  else {
    if (fd->read(fd, buf, new_bhead->bhead.len) != new_bhead->bhead.len) {
      success = false;
    }
  }
  if (fd->seek(fd, offset_backup, SEEK_SET) == -1) {
    success = false;
  }
  return success;
}

static BHead *blo_bhead_read_full(FileData *fd, BHead *thisblock)
{
  BHeadN *new_bhead = BHEADN_FROM_BHEAD(thisblock);
  BHeadN *new_bhead_data = MEM_mallocN(sizeof(BHeadN) + new_bhead->bhead.len, "new_bhead");
  new_bhead_data->bhead = new_bhead->bhead;
  new_bhead_data->file_offset = new_bhead->file_offset;
  new_bhead_data->has_data = true;
  if (!blo_bhead_read_data(fd, thisblock, new_bhead_data + 1)) {
    MEM_freeN(new_bhead_data);
    return NULL;
  }
  return &new_bhead_data->bhead;
}
#endif /* USE_BHEAD_READ_ON_DEMAND */

/* Warning! Caller's responsibility to ensure given bhead **is** and ID one! */
const char *blo_bhead_id_name(const FileData *fd, const BHead *bhead)
{
  return (const char *)POINTER_OFFSET(bhead, sizeof(*bhead) + fd->id_name_offs);
}

static void decode_blender_header(FileData *fd)
{
  char header[SIZEOFBLENDERHEADER], num[4];
  int readsize;

  /* read in the header data */
  readsize = fd->read(fd, header, sizeof(header));

  if (readsize == sizeof(header) && STREQLEN(header, "BLENDER", 7) && ELEM(header[7], '_', '-') &&
      ELEM(header[8], 'v', 'V') &&
      (isdigit(header[9]) && isdigit(header[10]) && isdigit(header[11]))) {
    fd->flags |= FD_FLAGS_FILE_OK;

    /* what size are pointers in the file ? */
    if (header[7] == '_') {
      fd->flags |= FD_FLAGS_FILE_POINTSIZE_IS_4;
      if (sizeof(void *) != 4) {
        fd->flags |= FD_FLAGS_POINTSIZE_DIFFERS;
      }
    }
    else {
      if (sizeof(void *) != 8) {
        fd->flags |= FD_FLAGS_POINTSIZE_DIFFERS;
      }
    }

    /* is the file saved in a different endian
     * than we need ?
     */
    if (((header[8] == 'v') ? L_ENDIAN : B_ENDIAN) != ENDIAN_ORDER) {
      fd->flags |= FD_FLAGS_SWITCH_ENDIAN;
    }

    /* get the version number */
    memcpy(num, header + 9, 3);
    num[3] = 0;
    fd->fileversion = atoi(num);
  }
}

/**
 * \return Success if the file is read correctly, else set \a r_error_message.
 */
static bool read_file_dna(FileData *fd, const char **r_error_message)
{
  BHead *bhead;
  int subversion = 0;

  for (bhead = blo_bhead_first(fd); bhead; bhead = blo_bhead_next(fd, bhead)) {
    if (bhead->code == GLOB) {
      /* Before this, the subversion didn't exist in 'FileGlobal' so the subversion
       * value isn't accessible for the purpose of DNA versioning in this case. */
      if (fd->fileversion <= 242) {
        continue;
      }
      /* We can't use read_global because this needs 'DNA1' to be decoded,
       * however the first 4 chars are _always_ the subversion. */
      FileGlobal *fg = (void *)&bhead[1];
      BLI_STATIC_ASSERT(offsetof(FileGlobal, subvstr) == 0, "Must be first: subvstr")
      char num[5];
      memcpy(num, fg->subvstr, 4);
      num[4] = 0;
      subversion = atoi(num);
    }
    else if (bhead->code == DNA1) {
      const bool do_endian_swap = (fd->flags & FD_FLAGS_SWITCH_ENDIAN) != 0;

      fd->filesdna = DNA_sdna_from_data(
          &bhead[1], bhead->len, do_endian_swap, true, r_error_message);
      if (fd->filesdna) {
        blo_do_versions_dna(fd->filesdna, fd->fileversion, subversion);
        fd->compflags = DNA_struct_get_compareflags(fd->filesdna, fd->memsdna);
        /* used to retrieve ID names from (bhead+1) */
        fd->id_name_offs = DNA_elem_offset(fd->filesdna, "ID", "char", "name[]");

        return true;
      }
      else {
        return false;
      }
    }
    else if (bhead->code == ENDB) {
      break;
    }
  }

  *r_error_message = "Missing DNA block";
  return false;
}

static int *read_file_thumbnail(FileData *fd)
{
  BHead *bhead;
  int *blend_thumb = NULL;

  for (bhead = blo_bhead_first(fd); bhead; bhead = blo_bhead_next(fd, bhead)) {
    if (bhead->code == TEST) {
      const bool do_endian_swap = (fd->flags & FD_FLAGS_SWITCH_ENDIAN) != 0;
      int *data = (int *)(bhead + 1);

      if (bhead->len < (2 * sizeof(int))) {
        break;
      }

      if (do_endian_swap) {
        BLI_endian_switch_int32(&data[0]);
        BLI_endian_switch_int32(&data[1]);
      }

      const int width = data[0];
      const int height = data[1];
      if (!BLEN_THUMB_MEMSIZE_IS_VALID(width, height)) {
        break;
      }
      if (bhead->len < BLEN_THUMB_MEMSIZE_FILE(width, height)) {
        break;
      }

      blend_thumb = data;
      break;
    }
    else if (bhead->code != REND) {
      /* Thumbnail is stored in TEST immediately after first REND... */
      break;
    }
  }

  return blend_thumb;
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name File Data API
 * \{ */

/* Regular file reading. */

static int fd_read_data_from_file(FileData *filedata, void *buffer, uint size)
{
  int readsize = read(filedata->filedes, buffer, size);

  if (readsize < 0) {
    readsize = EOF;
  }
  else {
    filedata->file_offset += readsize;
  }

  return (readsize);
}

static off64_t fd_seek_data_from_file(FileData *filedata, off64_t offset, int whence)
{
  filedata->file_offset = lseek(filedata->filedes, offset, whence);
  return filedata->file_offset;
}

/* GZip file reading. */

static int fd_read_gzip_from_file(FileData *filedata, void *buffer, uint size)
{
  int readsize = gzread(filedata->gzfiledes, buffer, size);

  if (readsize < 0) {
    readsize = EOF;
  }
  else {
    filedata->file_offset += readsize;
  }

  return (readsize);
}

/* Memory reading. */

static int fd_read_from_memory(FileData *filedata, void *buffer, uint size)
{
  /* don't read more bytes then there are available in the buffer */
  int readsize = (int)MIN2(size, (uint)(filedata->buffersize - filedata->file_offset));

  memcpy(buffer, filedata->buffer + filedata->file_offset, readsize);
  filedata->file_offset += readsize;

  return (readsize);
}

/* MemFile reading. */

static int fd_read_from_memfile(FileData *filedata, void *buffer, uint size)
{
  static size_t seek = SIZE_MAX; /* the current position */
  static size_t offset = 0;      /* size of previous chunks */
  static MemFileChunk *chunk = NULL;
  size_t chunkoffset, readsize, totread;

  if (size == 0) {
    return 0;
  }

  if (seek != (size_t)filedata->file_offset) {
    chunk = filedata->memfile->chunks.first;
    seek = 0;

    while (chunk) {
      if (seek + chunk->size > (size_t)filedata->file_offset) {
        break;
      }
      seek += chunk->size;
      chunk = chunk->next;
    }
    offset = seek;
    seek = filedata->file_offset;
  }

  if (chunk) {
    totread = 0;

    do {
      /* first check if it's on the end if current chunk */
      if (seek - offset == chunk->size) {
        offset += chunk->size;
        chunk = chunk->next;
      }

      /* debug, should never happen */
      if (chunk == NULL) {
        printf("illegal read, chunk zero\n");
        return 0;
      }

      chunkoffset = seek - offset;
      readsize = size - totread;

      /* data can be spread over multiple chunks, so clamp size
       * to within this chunk, and then it will read further in
       * the next chunk */
      if (chunkoffset + readsize > chunk->size) {
        readsize = chunk->size - chunkoffset;
      }

      memcpy(POINTER_OFFSET(buffer, totread), chunk->buf + chunkoffset, readsize);
      totread += readsize;
      filedata->file_offset += readsize;
      seek += readsize;
    } while (totread < size);

    return totread;
  }

  return 0;
}

static FileData *filedata_new(void)
{
  FileData *fd = MEM_callocN(sizeof(FileData), "FileData");

  fd->filedes = -1;
  fd->gzfiledes = NULL;

  fd->memsdna = DNA_sdna_current_get();

  fd->datamap = oldnewmap_new();
  fd->globmap = oldnewmap_new();
  fd->libmap = oldnewmap_new();

  return fd;
}

static FileData *blo_decode_and_check(FileData *fd, ReportList *reports)
{
  decode_blender_header(fd);

  if (fd->flags & FD_FLAGS_FILE_OK) {
    const char *error_message = NULL;
    if (read_file_dna(fd, &error_message) == false) {
      BKE_reportf(
          reports, RPT_ERROR, "Failed to read blend file '%s': %s", fd->relabase, error_message);
      blo_filedata_free(fd);
      fd = NULL;
    }
  }
  else {
    BKE_reportf(
        reports, RPT_ERROR, "Failed to read blend file '%s', not a blend file", fd->relabase);
    blo_filedata_free(fd);
    fd = NULL;
  }

  return fd;
}

static FileData *blo_filedata_from_file_descriptor(const char *filepath,
                                                   ReportList *reports,
                                                   int file)
{
  FileDataReadFn *read_fn = NULL;
  FileDataSeekFn *seek_fn = NULL; /* Optional. */

  gzFile gzfile = (gzFile)Z_NULL;

  char header[7];

  /* Regular file. */
  errno = 0;
  if (read(file, header, sizeof(header)) != sizeof(header)) {
    BKE_reportf(reports,
                RPT_WARNING,
                "Unable to read '%s': %s",
                filepath,
                errno ? strerror(errno) : TIP_("insufficient content"));
    return NULL;
  }
  else {
    lseek(file, 0, SEEK_SET);
  }

  /* Regular file. */
  if (memcmp(header, "BLENDER", sizeof(header)) == 0) {
    read_fn = fd_read_data_from_file;
    seek_fn = fd_seek_data_from_file;
  }

  /* Gzip file. */
  errno = 0;
  if ((read_fn == NULL) &&
      /* Check header magic. */
      (header[0] == 0x1f && header[1] == 0x8b)) {
    gzfile = BLI_gzopen(filepath, "rb");
    if (gzfile == (gzFile)Z_NULL) {
      BKE_reportf(reports,
                  RPT_WARNING,
                  "Unable to open '%s': %s",
                  filepath,
                  errno ? strerror(errno) : TIP_("unknown error reading file"));
      return NULL;
    }
    else {
      /* 'seek_fn' is too slow for gzip, don't set it. */
      read_fn = fd_read_gzip_from_file;
      /* Caller must close. */
      file = -1;
    }
  }

  if (read_fn == NULL) {
    BKE_reportf(reports, RPT_WARNING, "Unrecognized file format '%s'", filepath);
    return NULL;
  }

  FileData *fd = filedata_new();

  fd->filedes = file;
  fd->gzfiledes = gzfile;

  fd->read = read_fn;
  fd->seek = seek_fn;

  return fd;
}

static FileData *blo_filedata_from_file_open(const char *filepath, ReportList *reports)
{
  errno = 0;
  const int file = BLI_open(filepath, O_BINARY | O_RDONLY, 0);
  if (file == -1) {
    BKE_reportf(reports,
                RPT_WARNING,
                "Unable to open '%s': %s",
                filepath,
                errno ? strerror(errno) : TIP_("unknown error reading file"));
    return NULL;
  }
  FileData *fd = blo_filedata_from_file_descriptor(filepath, reports, file);
  if ((fd == NULL) || (fd->filedes == -1)) {
    close(file);
  }
  return fd;
}

/* cannot be called with relative paths anymore! */
/* on each new library added, it now checks for the current FileData and expands relativeness */
FileData *blo_filedata_from_file(const char *filepath, ReportList *reports)
{
  FileData *fd = blo_filedata_from_file_open(filepath, reports);
  if (fd != NULL) {
    /* needed for library_append and read_libraries */
    BLI_strncpy(fd->relabase, filepath, sizeof(fd->relabase));

    return blo_decode_and_check(fd, reports);
  }
  return NULL;
}

/**
 * Same as blo_filedata_from_file(), but does not reads DNA data, only header.
 * Use it for light access (e.g. thumbnail reading).
 */
static FileData *blo_filedata_from_file_minimal(const char *filepath)
{
  FileData *fd = blo_filedata_from_file_open(filepath, NULL);
  if (fd != NULL) {
    decode_blender_header(fd);
    if (fd->flags & FD_FLAGS_FILE_OK) {
      return fd;
    }
    blo_filedata_free(fd);
  }
  return NULL;
}

static int fd_read_gzip_from_memory(FileData *filedata, void *buffer, uint size)
{
  int err;

  filedata->strm.next_out = (Bytef *)buffer;
  filedata->strm.avail_out = size;

  // Inflate another chunk.
  err = inflate(&filedata->strm, Z_SYNC_FLUSH);

  if (err == Z_STREAM_END) {
    return 0;
  }
  else if (err != Z_OK) {
    printf("fd_read_gzip_from_memory: zlib error\n");
    return 0;
  }

  filedata->file_offset += size;

  return (size);
}

static int fd_read_gzip_from_memory_init(FileData *fd)
{

  fd->strm.next_in = (Bytef *)fd->buffer;
  fd->strm.avail_in = fd->buffersize;
  fd->strm.total_out = 0;
  fd->strm.zalloc = Z_NULL;
  fd->strm.zfree = Z_NULL;

  if (inflateInit2(&fd->strm, (16 + MAX_WBITS)) != Z_OK) {
    return 0;
  }

  fd->read = fd_read_gzip_from_memory;

  return 1;
}

FileData *blo_filedata_from_memory(const void *mem, int memsize, ReportList *reports)
{
  if (!mem || memsize < SIZEOFBLENDERHEADER) {
    BKE_report(reports, RPT_WARNING, (mem) ? TIP_("Unable to read") : TIP_("Unable to open"));
    return NULL;
  }
  else {
    FileData *fd = filedata_new();
    const char *cp = mem;

    fd->buffer = mem;
    fd->buffersize = memsize;

    /* test if gzip */
    if (cp[0] == 0x1f && cp[1] == 0x8b) {
      if (0 == fd_read_gzip_from_memory_init(fd)) {
        blo_filedata_free(fd);
        return NULL;
      }
    }
    else {
      fd->read = fd_read_from_memory;
    }

    fd->flags |= FD_FLAGS_NOT_MY_BUFFER;

    return blo_decode_and_check(fd, reports);
  }
}

FileData *blo_filedata_from_memfile(MemFile *memfile, ReportList *reports)
{
  if (!memfile) {
    BKE_report(reports, RPT_WARNING, "Unable to open blend <memory>");
    return NULL;
  }
  else {
    FileData *fd = filedata_new();
    fd->memfile = memfile;

    fd->read = fd_read_from_memfile;
    fd->flags |= FD_FLAGS_NOT_MY_BUFFER;

    return blo_decode_and_check(fd, reports);
  }
}

void blo_filedata_free(FileData *fd)
{
  if (fd) {
    if (fd->filedes != -1) {
      close(fd->filedes);
    }

    if (fd->gzfiledes != NULL) {
      gzclose(fd->gzfiledes);
    }

    if (fd->strm.next_in) {
      if (inflateEnd(&fd->strm) != Z_OK) {
        printf("close gzip stream error\n");
      }
    }

    if (fd->buffer && !(fd->flags & FD_FLAGS_NOT_MY_BUFFER)) {
      MEM_freeN((void *)fd->buffer);
      fd->buffer = NULL;
    }

    /* Free all BHeadN data blocks */
#ifndef NDEBUG
    BLI_freelistN(&fd->bhead_list);
#else
    /* Sanity check we're not keeping memory we don't need. */
    LISTBASE_FOREACH_MUTABLE (BHeadN *, new_bhead, &fd->bhead_list) {
      if (fd->seek != NULL && BHEAD_USE_READ_ON_DEMAND(&new_bhead->bhead)) {
        BLI_assert(new_bhead->has_data == 0);
      }
      MEM_freeN(new_bhead);
    }
#endif

    if (fd->filesdna) {
      DNA_sdna_free(fd->filesdna);
    }
    if (fd->compflags) {
      MEM_freeN((void *)fd->compflags);
    }

    if (fd->datamap) {
      oldnewmap_free(fd->datamap);
    }
    if (fd->globmap) {
      oldnewmap_free(fd->globmap);
    }
    if (fd->imamap) {
      oldnewmap_free(fd->imamap);
    }
    if (fd->movieclipmap) {
      oldnewmap_free(fd->movieclipmap);
    }
    if (fd->scenemap) {
      oldnewmap_free(fd->scenemap);
    }
    if (fd->soundmap) {
      oldnewmap_free(fd->soundmap);
    }
    if (fd->packedmap) {
      oldnewmap_free(fd->packedmap);
    }
    if (fd->libmap && !(fd->flags & FD_FLAGS_NOT_MY_LIBMAP)) {
      oldnewmap_free(fd->libmap);
    }
    if (fd->bheadmap) {
      MEM_freeN(fd->bheadmap);
    }

#ifdef USE_GHASH_BHEAD
    if (fd->bhead_idname_hash) {
      BLI_ghash_free(fd->bhead_idname_hash, NULL, NULL);
    }
#endif

    MEM_freeN(fd);
  }
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Public Utilities
 * \{ */

/**
 * Check whether given path ends with a blend file compatible extension
 * (`.blend`, `.ble` or `.blend.gz`).
 *
 * \param str: The path to check.
 * \return true is this path ends with a blender file extension.
 */
bool BLO_has_bfile_extension(const char *str)
{
  const char *ext_test[4] = {".blend", ".ble", ".blend.gz", NULL};
  return BLI_path_extension_check_array(str, ext_test);
}

/**
 * Try to explode given path into its 'library components'
 * (i.e. a .blend file, id type/group, and data-block itself).
 *
 * \param path: the full path to explode.
 * \param r_dir: the string that'll contain path up to blend file itself ('library' path).
 * WARNING! Must be #FILE_MAX_LIBEXTRA long (it also stores group and name strings)!
 * \param r_group: the string that'll contain 'group' part of the path, if any. May be NULL.
 * \param r_name: the string that'll contain data's name part of the path, if any. May be NULL.
 * \return true if path contains a blend file.
 */
bool BLO_library_path_explode(const char *path, char *r_dir, char **r_group, char **r_name)
{
  /* We might get some data names with slashes,
   * so we have to go up in path until we find blend file itself,
   * then we now next path item is group, and everything else is data name. */
  char *slash = NULL, *prev_slash = NULL, c = '\0';

  r_dir[0] = '\0';
  if (r_group) {
    *r_group = NULL;
  }
  if (r_name) {
    *r_name = NULL;
  }

  /* if path leads to an existing directory, we can be sure we're not (in) a library */
  if (BLI_is_dir(path)) {
    return false;
  }

  strcpy(r_dir, path);

  while ((slash = (char *)BLI_last_slash(r_dir))) {
    char tc = *slash;
    *slash = '\0';
    if (BLO_has_bfile_extension(r_dir) && BLI_is_file(r_dir)) {
      break;
    }
    else if (STREQ(r_dir, BLO_EMBEDDED_STARTUP_BLEND)) {
      break;
    }

    if (prev_slash) {
      *prev_slash = c;
    }
    prev_slash = slash;
    c = tc;
  }

  if (!slash) {
    return false;
  }

  if (slash[1] != '\0') {
    BLI_assert(strlen(slash + 1) < BLO_GROUP_MAX);
    if (r_group) {
      *r_group = slash + 1;
    }
  }

  if (prev_slash && (prev_slash[1] != '\0')) {
    BLI_assert(strlen(prev_slash + 1) < MAX_ID_NAME - 2);
    if (r_name) {
      *r_name = prev_slash + 1;
    }
  }

  return true;
}

/**
 * Does a very light reading of given .blend file to extract its stored thumbnail.
 *
 * \param filepath: The path of the file to extract thumbnail from.
 * \return The raw thumbnail
 * (MEM-allocated, as stored in file, use #BKE_main_thumbnail_to_imbuf()
 * to convert it to ImBuf image).
 */
BlendThumbnail *BLO_thumbnail_from_file(const char *filepath)
{
  FileData *fd;
  BlendThumbnail *data = NULL;
  int *fd_data;

  fd = blo_filedata_from_file_minimal(filepath);
  fd_data = fd ? read_file_thumbnail(fd) : NULL;

  if (fd_data) {
    const int width = fd_data[0];
    const int height = fd_data[1];
    if (BLEN_THUMB_MEMSIZE_IS_VALID(width, height)) {
      const size_t sz = BLEN_THUMB_MEMSIZE(width, height);
      data = MEM_mallocN(sz, __func__);
      if (data) {
        BLI_assert((sz - sizeof(*data)) ==
                   (BLEN_THUMB_MEMSIZE_FILE(width, height) - (sizeof(*fd_data) * 2)));
        data->width = width;
        data->height = height;
        memcpy(data->rect, &fd_data[2], sz - sizeof(*data));
      }
    }
  }

  blo_filedata_free(fd);

  return data;
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Old/New Pointer Map
 * \{ */

/* only direct databocks */
static void *newdataadr(FileData *fd, const void *adr)
{
  return oldnewmap_lookup_and_inc(fd->datamap, adr, true);
}

/* only direct databocks */
static void *newdataadr_no_us(FileData *fd, const void *adr)
{
  return oldnewmap_lookup_and_inc(fd->datamap, adr, false);
}

/* direct datablocks with global linking */
static void *newglobadr(FileData *fd, const void *adr)
{
  return oldnewmap_lookup_and_inc(fd->globmap, adr, true);
}

/* used to restore image data after undo */
static void *newimaadr(FileData *fd, const void *adr)
{
  if (fd->imamap && adr) {
    return oldnewmap_lookup_and_inc(fd->imamap, adr, true);
  }
  return NULL;
}

/* used to restore scene data after undo */
static void *newsceadr(FileData *fd, const void *adr)
{
  if (fd->scenemap && adr) {
    return oldnewmap_lookup_and_inc(fd->scenemap, adr, true);
  }
  return NULL;
}

/* used to restore movie clip data after undo */
static void *newmclipadr(FileData *fd, const void *adr)
{
  if (fd->movieclipmap && adr) {
    return oldnewmap_lookup_and_inc(fd->movieclipmap, adr, true);
  }
  return NULL;
}

/* used to restore sound data after undo */
static void *newsoundadr(FileData *fd, const void *adr)
{
  if (fd->soundmap && adr) {
    return oldnewmap_lookup_and_inc(fd->soundmap, adr, true);
  }
  return NULL;
}

/* used to restore packed data after undo */
static void *newpackedadr(FileData *fd, const void *adr)
{
  if (fd->packedmap && adr) {
    return oldnewmap_lookup_and_inc(fd->packedmap, adr, true);
  }

  return oldnewmap_lookup_and_inc(fd->datamap, adr, true);
}

/* only lib data */
static void *newlibadr(FileData *fd, const void *lib, const void *adr)
{
  return oldnewmap_liblookup(fd->libmap, adr, lib);
}

/* only lib data */
void *blo_do_versions_newlibadr(FileData *fd, const void *lib, const void *adr)
{
  return newlibadr(fd, lib, adr);
}

/* increases user number */
static void *newlibadr_us(FileData *fd, const void *lib, const void *adr)
{
  ID *id = newlibadr(fd, lib, adr);

  id_us_plus_no_lib(id);

  return id;
}

/* increases user number */
void *blo_do_versions_newlibadr_us(FileData *fd, const void *lib, const void *adr)
{
  return newlibadr_us(fd, lib, adr);
}

/* ensures real user */
static void *newlibadr_real_us(FileData *fd, const void *lib, const void *adr)
{
  ID *id = newlibadr(fd, lib, adr);

  id_us_ensure_real(id);

  return id;
}

static void change_link_placeholder_to_real_ID_pointer_fd(FileData *fd, const void *old, void *new)
{
  for (int i = 0; i < fd->libmap->nentries; i++) {
    OldNew *entry = &fd->libmap->entries[i];

    if (old == entry->newp && entry->nr == ID_LINK_PLACEHOLDER) {
      entry->newp = new;
      if (new) {
        entry->nr = GS(((ID *)new)->name);
      }
    }
  }
}

static void change_link_placeholder_to_real_ID_pointer(ListBase *mainlist,
                                                       FileData *basefd,
                                                       void *old,
                                                       void *new)
{
  Main *mainptr;

  for (mainptr = mainlist->first; mainptr; mainptr = mainptr->next) {
    FileData *fd;

    if (mainptr->curlib) {
      fd = mainptr->curlib->filedata;
    }
    else {
      fd = basefd;
    }

    if (fd) {
      change_link_placeholder_to_real_ID_pointer_fd(fd, old, new);
    }
  }
}

/* lib linked proxy objects point to our local data, we need
 * to clear that pointer before reading the undo memfile since
 * the object might be removed, it is set again in reading
 * if the local object still exists.
 * This is only valid for local proxy objects though, linked ones should not be affected here.
 */
void blo_clear_proxy_pointers_from_lib(Main *oldmain)
{
  Object *ob = oldmain->objects.first;

  for (; ob; ob = ob->id.next) {
    if (ob->id.lib != NULL && ob->proxy_from != NULL && ob->proxy_from->id.lib == NULL) {
      ob->proxy_from = NULL;
    }
  }
}

void blo_make_scene_pointer_map(FileData *fd, Main *oldmain)
{
  Scene *sce = oldmain->scenes.first;

  fd->scenemap = oldnewmap_new();

  for (; sce; sce = sce->id.next) {
    if (sce->eevee.light_cache) {
      struct LightCache *light_cache = sce->eevee.light_cache;
      oldnewmap_insert(fd->scenemap, light_cache, light_cache, 0);
    }
  }
}

void blo_end_scene_pointer_map(FileData *fd, Main *oldmain)
{
  OldNew *entry = fd->scenemap->entries;
  Scene *sce = oldmain->scenes.first;
  int i;

  /* used entries were restored, so we put them to zero */
  for (i = 0; i < fd->scenemap->nentries; i++, entry++) {
    if (entry->nr > 0) {
      entry->newp = NULL;
    }
  }

  for (; sce; sce = sce->id.next) {
    sce->eevee.light_cache = newsceadr(fd, sce->eevee.light_cache);
  }
}

void blo_make_image_pointer_map(FileData *fd, Main *oldmain)
{
  Image *ima = oldmain->images.first;
  Scene *sce = oldmain->scenes.first;
  int a;

  fd->imamap = oldnewmap_new();

  for (; ima; ima = ima->id.next) {
    if (ima->cache) {
      oldnewmap_insert(fd->imamap, ima->cache, ima->cache, 0);
    }
    for (a = 0; a < TEXTARGET_COUNT; a++) {
      if (ima->gputexture[a]) {
        oldnewmap_insert(fd->imamap, ima->gputexture[a], ima->gputexture[a], 0);
      }
    }
    if (ima->rr) {
      oldnewmap_insert(fd->imamap, ima->rr, ima->rr, 0);
    }
    LISTBASE_FOREACH (RenderSlot *, slot, &ima->renderslots) {
      if (slot->render) {
        oldnewmap_insert(fd->imamap, slot->render, slot->render, 0);
      }
    }
  }
  for (; sce; sce = sce->id.next) {
    if (sce->nodetree && sce->nodetree->previews) {
      bNodeInstanceHashIterator iter;
      NODE_INSTANCE_HASH_ITER (iter, sce->nodetree->previews) {
        bNodePreview *preview = BKE_node_instance_hash_iterator_get_value(&iter);
        oldnewmap_insert(fd->imamap, preview, preview, 0);
      }
    }
  }
}

/* set old main image ibufs to zero if it has been restored */
/* this works because freeing old main only happens after this call */
void blo_end_image_pointer_map(FileData *fd, Main *oldmain)
{
  OldNew *entry = fd->imamap->entries;
  Image *ima = oldmain->images.first;
  Scene *sce = oldmain->scenes.first;
  int i;

  /* used entries were restored, so we put them to zero */
  for (i = 0; i < fd->imamap->nentries; i++, entry++) {
    if (entry->nr > 0) {
      entry->newp = NULL;
    }
  }

  for (; ima; ima = ima->id.next) {
    ima->cache = newimaadr(fd, ima->cache);
    if (ima->cache == NULL) {
      ima->gpuflag = 0;
      ima->gpuframenr = INT_MAX;
      for (i = 0; i < TEXTARGET_COUNT; i++) {
        ima->gputexture[i] = NULL;
      }
      ima->rr = NULL;
    }
    LISTBASE_FOREACH (RenderSlot *, slot, &ima->renderslots) {
      slot->render = newimaadr(fd, slot->render);
    }

    for (i = 0; i < TEXTARGET_COUNT; i++) {
      ima->gputexture[i] = newimaadr(fd, ima->gputexture[i]);
    }
    ima->rr = newimaadr(fd, ima->rr);
  }
  for (; sce; sce = sce->id.next) {
    if (sce->nodetree && sce->nodetree->previews) {
      bNodeInstanceHash *new_previews = BKE_node_instance_hash_new("node previews");
      bNodeInstanceHashIterator iter;

      /* reconstruct the preview hash, only using remaining pointers */
      NODE_INSTANCE_HASH_ITER (iter, sce->nodetree->previews) {
        bNodePreview *preview = BKE_node_instance_hash_iterator_get_value(&iter);
        if (preview) {
          bNodePreview *new_preview = newimaadr(fd, preview);
          if (new_preview) {
            bNodeInstanceKey key = BKE_node_instance_hash_iterator_get_key(&iter);
            BKE_node_instance_hash_insert(new_previews, key, new_preview);
          }
        }
      }
      BKE_node_instance_hash_free(sce->nodetree->previews, NULL);
      sce->nodetree->previews = new_previews;
    }
  }
}

void blo_make_movieclip_pointer_map(FileData *fd, Main *oldmain)
{
  MovieClip *clip = oldmain->movieclips.first;
  Scene *sce = oldmain->scenes.first;

  fd->movieclipmap = oldnewmap_new();

  for (; clip; clip = clip->id.next) {
    if (clip->cache) {
      oldnewmap_insert(fd->movieclipmap, clip->cache, clip->cache, 0);
    }

    if (clip->tracking.camera.intrinsics) {
      oldnewmap_insert(
          fd->movieclipmap, clip->tracking.camera.intrinsics, clip->tracking.camera.intrinsics, 0);
    }
  }

  for (; sce; sce = sce->id.next) {
    if (sce->nodetree) {
      bNode *node;
      for (node = sce->nodetree->nodes.first; node; node = node->next) {
        if (node->type == CMP_NODE_MOVIEDISTORTION) {
          oldnewmap_insert(fd->movieclipmap, node->storage, node->storage, 0);
        }
      }
    }
  }
}

/* set old main movie clips caches to zero if it has been restored */
/* this works because freeing old main only happens after this call */
void blo_end_movieclip_pointer_map(FileData *fd, Main *oldmain)
{
  OldNew *entry = fd->movieclipmap->entries;
  MovieClip *clip = oldmain->movieclips.first;
  Scene *sce = oldmain->scenes.first;
  int i;

  /* used entries were restored, so we put them to zero */
  for (i = 0; i < fd->movieclipmap->nentries; i++, entry++) {
    if (entry->nr > 0) {
      entry->newp = NULL;
    }
  }

  for (; clip; clip = clip->id.next) {
    clip->cache = newmclipadr(fd, clip->cache);
    clip->tracking.camera.intrinsics = newmclipadr(fd, clip->tracking.camera.intrinsics);
    BLI_freelistN(&clip->runtime.gputextures);
  }

  for (; sce; sce = sce->id.next) {
    if (sce->nodetree) {
      bNode *node;
      for (node = sce->nodetree->nodes.first; node; node = node->next) {
        if (node->type == CMP_NODE_MOVIEDISTORTION) {
          node->storage = newmclipadr(fd, node->storage);
        }
      }
    }
  }
}

void blo_make_sound_pointer_map(FileData *fd, Main *oldmain)
{
  bSound *sound = oldmain->sounds.first;

  fd->soundmap = oldnewmap_new();

  for (; sound; sound = sound->id.next) {
    if (sound->waveform) {
      oldnewmap_insert(fd->soundmap, sound->waveform, sound->waveform, 0);
    }
  }
}

/* set old main sound caches to zero if it has been restored */
/* this works because freeing old main only happens after this call */
void blo_end_sound_pointer_map(FileData *fd, Main *oldmain)
{
  OldNew *entry = fd->soundmap->entries;
  bSound *sound = oldmain->sounds.first;
  int i;

  /* used entries were restored, so we put them to zero */
  for (i = 0; i < fd->soundmap->nentries; i++, entry++) {
    if (entry->nr > 0) {
      entry->newp = NULL;
    }
  }

  for (; sound; sound = sound->id.next) {
    sound->waveform = newsoundadr(fd, sound->waveform);
  }
}

/* XXX disabled this feature - packed files also belong in temp saves and quit.blend,
 * to make restore work. */

static void insert_packedmap(FileData *fd, PackedFile *pf)
{
  oldnewmap_insert(fd->packedmap, pf, pf, 0);
  oldnewmap_insert(fd->packedmap, pf->data, pf->data, 0);
}

void blo_make_packed_pointer_map(FileData *fd, Main *oldmain)
{
  Image *ima;
  VFont *vfont;
  bSound *sound;
  Library *lib;

  fd->packedmap = oldnewmap_new();

  for (ima = oldmain->images.first; ima; ima = ima->id.next) {
    ImagePackedFile *imapf;

    if (ima->packedfile) {
      insert_packedmap(fd, ima->packedfile);
    }

    for (imapf = ima->packedfiles.first; imapf; imapf = imapf->next) {
      if (imapf->packedfile) {
        insert_packedmap(fd, imapf->packedfile);
      }
    }
  }

  for (vfont = oldmain->fonts.first; vfont; vfont = vfont->id.next) {
    if (vfont->packedfile) {
      insert_packedmap(fd, vfont->packedfile);
    }
  }

  for (sound = oldmain->sounds.first; sound; sound = sound->id.next) {
    if (sound->packedfile) {
      insert_packedmap(fd, sound->packedfile);
    }
  }

  for (lib = oldmain->libraries.first; lib; lib = lib->id.next) {
    if (lib->packedfile) {
      insert_packedmap(fd, lib->packedfile);
    }
  }
}

/* set old main packed data to zero if it has been restored */
/* this works because freeing old main only happens after this call */
void blo_end_packed_pointer_map(FileData *fd, Main *oldmain)
{
  Image *ima;
  VFont *vfont;
  bSound *sound;
  Library *lib;
  OldNew *entry = fd->packedmap->entries;
  int i;

  /* used entries were restored, so we put them to zero */
  for (i = 0; i < fd->packedmap->nentries; i++, entry++) {
    if (entry->nr > 0) {
      entry->newp = NULL;
    }
  }

  for (ima = oldmain->images.first; ima; ima = ima->id.next) {
    ImagePackedFile *imapf;

    ima->packedfile = newpackedadr(fd, ima->packedfile);

    for (imapf = ima->packedfiles.first; imapf; imapf = imapf->next) {
      imapf->packedfile = newpackedadr(fd, imapf->packedfile);
    }
  }

  for (vfont = oldmain->fonts.first; vfont; vfont = vfont->id.next) {
    vfont->packedfile = newpackedadr(fd, vfont->packedfile);
  }

  for (sound = oldmain->sounds.first; sound; sound = sound->id.next) {
    sound->packedfile = newpackedadr(fd, sound->packedfile);
  }

  for (lib = oldmain->libraries.first; lib; lib = lib->id.next) {
    lib->packedfile = newpackedadr(fd, lib->packedfile);
  }
}

/* undo file support: add all library pointers in lookup */
void blo_add_library_pointer_map(ListBase *old_mainlist, FileData *fd)
{
  Main *ptr = old_mainlist->first;
  ListBase *lbarray[MAX_LIBARRAY];

  for (ptr = ptr->next; ptr; ptr = ptr->next) {
    int i = set_listbasepointers(ptr, lbarray);
    while (i--) {
      ID *id;
      for (id = lbarray[i]->first; id; id = id->next) {
        oldnewmap_insert(fd->libmap, id, id, GS(id->name));
      }
    }
  }

  fd->old_mainlist = old_mainlist;
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name DNA Struct Loading
 * \{ */

static void switch_endian_structs(const struct SDNA *filesdna, BHead *bhead)
{
  int blocksize, nblocks;
  char *data;

  data = (char *)(bhead + 1);
  blocksize = filesdna->types_size[filesdna->structs[bhead->SDNAnr][0]];

  nblocks = bhead->nr;
  while (nblocks--) {
    DNA_struct_switch_endian(filesdna, bhead->SDNAnr, data);

    data += blocksize;
  }
}

static void *read_struct(FileData *fd, BHead *bh, const char *blockname)
{
  void *temp = NULL;

  if (bh->len) {
#ifdef USE_BHEAD_READ_ON_DEMAND
    BHead *bh_orig = bh;
#endif

    /* switch is based on file dna */
    if (bh->SDNAnr && (fd->flags & FD_FLAGS_SWITCH_ENDIAN)) {
#ifdef USE_BHEAD_READ_ON_DEMAND
      if (BHEADN_FROM_BHEAD(bh)->has_data == false) {
        bh = blo_bhead_read_full(fd, bh);
        if (UNLIKELY(bh == NULL)) {
          fd->flags &= ~FD_FLAGS_FILE_OK;
          return NULL;
        }
      }
#endif
      switch_endian_structs(fd->filesdna, bh);
    }

    if (fd->compflags[bh->SDNAnr] != SDNA_CMP_REMOVED) {
      if (fd->compflags[bh->SDNAnr] == SDNA_CMP_NOT_EQUAL) {
#ifdef USE_BHEAD_READ_ON_DEMAND
        if (BHEADN_FROM_BHEAD(bh)->has_data == false) {
          bh = blo_bhead_read_full(fd, bh);
          if (UNLIKELY(bh == NULL)) {
            fd->flags &= ~FD_FLAGS_FILE_OK;
            return NULL;
          }
        }
#endif
        temp = DNA_struct_reconstruct(
            fd->memsdna, fd->filesdna, fd->compflags, bh->SDNAnr, bh->nr, (bh + 1));
      }
      else {
        /* SDNA_CMP_EQUAL */
        temp = MEM_mallocN(bh->len, blockname);
#ifdef USE_BHEAD_READ_ON_DEMAND
        if (BHEADN_FROM_BHEAD(bh)->has_data) {
          memcpy(temp, (bh + 1), bh->len);
        }
        else {
          /* Instead of allocating the bhead, then copying it,
           * read the data from the file directly into the memory. */
          if (UNLIKELY(!blo_bhead_read_data(fd, bh, temp))) {
            fd->flags &= ~FD_FLAGS_FILE_OK;
            MEM_freeN(temp);
            temp = NULL;
          }
        }
#else
        memcpy(temp, (bh + 1), bh->len);
#endif
      }
    }
#ifdef USE_BHEAD_READ_ON_DEMAND
    if (bh_orig != bh) {
      MEM_freeN(BHEADN_FROM_BHEAD(bh));
    }
#endif
  }

  return temp;
}

typedef void (*link_list_cb)(FileData *fd, void *data);

static void link_list_ex(FileData *fd, ListBase *lb, link_list_cb callback) /* only direct data */
{
  Link *ln, *prev;

  if (BLI_listbase_is_empty(lb)) {
    return;
  }

  lb->first = newdataadr(fd, lb->first);
  if (callback != NULL) {
    callback(fd, lb->first);
  }
  ln = lb->first;
  prev = NULL;
  while (ln) {
    ln->next = newdataadr(fd, ln->next);
    if (ln->next != NULL && callback != NULL) {
      callback(fd, ln->next);
    }
    ln->prev = prev;
    prev = ln;
    ln = ln->next;
  }
  lb->last = prev;
}

static void link_list(FileData *fd, ListBase *lb) /* only direct data */
{
  link_list_ex(fd, lb, NULL);
}

static void link_glob_list(FileData *fd, ListBase *lb) /* for glob data */
{
  Link *ln, *prev;
  void *poin;

  if (BLI_listbase_is_empty(lb)) {
    return;
  }
  poin = newdataadr(fd, lb->first);
  if (lb->first) {
    oldnewmap_insert(fd->globmap, lb->first, poin, 0);
  }
  lb->first = poin;

  ln = lb->first;
  prev = NULL;
  while (ln) {
    poin = newdataadr(fd, ln->next);
    if (ln->next) {
      oldnewmap_insert(fd->globmap, ln->next, poin, 0);
    }
    ln->next = poin;
    ln->prev = prev;
    prev = ln;
    ln = ln->next;
  }
  lb->last = prev;
}

static void test_pointer_array(FileData *fd, void **mat)
{
  int64_t *lpoin, *lmat;
  int *ipoin, *imat;
  size_t len;

  /* manually convert the pointer array in
   * the old dna format to a pointer array in
   * the new dna format.
   */
  if (*mat) {
    len = MEM_allocN_len(*mat) / fd->filesdna->pointer_size;

    if (fd->filesdna->pointer_size == 8 && fd->memsdna->pointer_size == 4) {
      ipoin = imat = MEM_malloc_arrayN(len, 4, "newmatar");
      lpoin = *mat;

      while (len-- > 0) {
        if ((fd->flags & FD_FLAGS_SWITCH_ENDIAN)) {
          BLI_endian_switch_int64(lpoin);
        }
        *ipoin = (int)((*lpoin) >> 3);
        ipoin++;
        lpoin++;
      }
      MEM_freeN(*mat);
      *mat = imat;
    }

    if (fd->filesdna->pointer_size == 4 && fd->memsdna->pointer_size == 8) {
      lpoin = lmat = MEM_malloc_arrayN(len, 8, "newmatar");
      ipoin = *mat;

      while (len-- > 0) {
        *lpoin = *ipoin;
        ipoin++;
        lpoin++;
      }
      MEM_freeN(*mat);
      *mat = lmat;
    }
  }
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Read ID Properties
 * \{ */

static void IDP_DirectLinkProperty(IDProperty *prop, int switch_endian, FileData *fd);
static void IDP_LibLinkProperty(IDProperty *prop, FileData *fd);

static void IDP_DirectLinkIDPArray(IDProperty *prop, int switch_endian, FileData *fd)
{
  IDProperty *array;
  int i;

  /* since we didn't save the extra buffer, set totallen to len */
  prop->totallen = prop->len;
  prop->data.pointer = newdataadr(fd, prop->data.pointer);

  array = (IDProperty *)prop->data.pointer;

  /* note!, idp-arrays didn't exist in 2.4x, so the pointer will be cleared
   * there's not really anything we can do to correct this, at least don't crash */
  if (array == NULL) {
    prop->len = 0;
    prop->totallen = 0;
  }

  for (i = 0; i < prop->len; i++) {
    IDP_DirectLinkProperty(&array[i], switch_endian, fd);
  }
}

static void IDP_DirectLinkArray(IDProperty *prop, int switch_endian, FileData *fd)
{
  IDProperty **array;
  int i;

  /* since we didn't save the extra buffer, set totallen to len */
  prop->totallen = prop->len;
  prop->data.pointer = newdataadr(fd, prop->data.pointer);

  if (prop->subtype == IDP_GROUP) {
    test_pointer_array(fd, prop->data.pointer);
    array = prop->data.pointer;

    for (i = 0; i < prop->len; i++) {
      IDP_DirectLinkProperty(array[i], switch_endian, fd);
    }
  }
  else if (prop->subtype == IDP_DOUBLE) {
    if (switch_endian) {
      BLI_endian_switch_double_array(prop->data.pointer, prop->len);
    }
  }
  else {
    if (switch_endian) {
      /* also used for floats */
      BLI_endian_switch_int32_array(prop->data.pointer, prop->len);
    }
  }
}

static void IDP_DirectLinkString(IDProperty *prop, FileData *fd)
{
  /*since we didn't save the extra string buffer, set totallen to len.*/
  prop->totallen = prop->len;
  prop->data.pointer = newdataadr(fd, prop->data.pointer);
}

static void IDP_DirectLinkGroup(IDProperty *prop, int switch_endian, FileData *fd)
{
  ListBase *lb = &prop->data.group;
  IDProperty *loop;

  link_list(fd, lb);

  /*Link child id properties now*/
  for (loop = prop->data.group.first; loop; loop = loop->next) {
    IDP_DirectLinkProperty(loop, switch_endian, fd);
  }
}

static void IDP_DirectLinkProperty(IDProperty *prop, int switch_endian, FileData *fd)
{
  switch (prop->type) {
    case IDP_GROUP:
      IDP_DirectLinkGroup(prop, switch_endian, fd);
      break;
    case IDP_STRING:
      IDP_DirectLinkString(prop, fd);
      break;
    case IDP_ARRAY:
      IDP_DirectLinkArray(prop, switch_endian, fd);
      break;
    case IDP_IDPARRAY:
      IDP_DirectLinkIDPArray(prop, switch_endian, fd);
      break;
    case IDP_DOUBLE:
      /* erg, stupid doubles.  since I'm storing them
       * in the same field as int val; val2 in the
       * IDPropertyData struct, they have to deal with
       * endianness specifically
       *
       * in theory, val and val2 would've already been swapped
       * if switch_endian is true, so we have to first unswap
       * them then reswap them as a single 64-bit entity.
       */

      if (switch_endian) {
        BLI_endian_switch_int32(&prop->data.val);
        BLI_endian_switch_int32(&prop->data.val2);
        BLI_endian_switch_int64((int64_t *)&prop->data.val);
      }
      break;
    case IDP_INT:
    case IDP_FLOAT:
    case IDP_ID:
      break; /* Nothing special to do here. */
    default:
      /* Unknown IDP type, nuke it (we cannot handle unknown types everywhere in code,
       * IDP are way too polymorphic to do it safely. */
      printf(
          "%s: found unknown IDProperty type %d, reset to Integer one !\n", __func__, prop->type);
      /* Note: we do not attempt to free unknown prop, we have no way to know how to do that! */
      prop->type = IDP_INT;
      prop->subtype = 0;
      IDP_Int(prop) = 0;
  }
}

#define IDP_DirectLinkGroup_OrFree(prop, switch_endian, fd) \
  _IDP_DirectLinkGroup_OrFree(prop, switch_endian, fd, __func__)

static void _IDP_DirectLinkGroup_OrFree(IDProperty **prop,
                                        int switch_endian,
                                        FileData *fd,
                                        const char *caller_func_id)
{
  if (*prop) {
    if ((*prop)->type == IDP_GROUP) {
      IDP_DirectLinkGroup(*prop, switch_endian, fd);
    }
    else {
      /* corrupt file! */
      printf("%s: found non group data, freeing type %d!\n", caller_func_id, (*prop)->type);
      /* don't risk id, data's likely corrupt. */
      // IDP_FreePropertyContent(*prop);
      *prop = NULL;
    }
  }
}

static void IDP_LibLinkProperty(IDProperty *prop, FileData *fd)
{
  if (!prop) {
    return;
  }

  switch (prop->type) {
    case IDP_ID: /* PointerProperty */
    {
      void *newaddr = newlibadr_us(fd, NULL, IDP_Id(prop));
      if (IDP_Id(prop) && !newaddr && G.debug) {
        printf("Error while loading \"%s\". Data not found in file!\n", prop->name);
      }
      prop->data.pointer = newaddr;
      break;
    }
    case IDP_IDPARRAY: /* CollectionProperty */
    {
      IDProperty *idp_array = IDP_IDPArray(prop);
      for (int i = 0; i < prop->len; i++) {
        IDP_LibLinkProperty(&(idp_array[i]), fd);
      }
      break;
    }
    case IDP_GROUP: /* PointerProperty */
    {
      for (IDProperty *loop = prop->data.group.first; loop; loop = loop->next) {
        IDP_LibLinkProperty(loop, fd);
      }
      break;
    }
    default:
      break; /* Nothing to do for other IDProps. */
  }
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Read Image Preview
 * \{ */

static PreviewImage *direct_link_preview_image(FileData *fd, PreviewImage *old_prv)
{
  PreviewImage *prv = newdataadr(fd, old_prv);

  if (prv) {
    int i;
    for (i = 0; i < NUM_ICON_SIZES; ++i) {
      if (prv->rect[i]) {
        prv->rect[i] = newdataadr(fd, prv->rect[i]);
      }
      prv->gputexture[i] = NULL;
    }
    prv->icon_id = 0;
    prv->tag = 0;
  }

  return prv;
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Read ID
 * \{ */

static void lib_link_id(FileData *fd, Main *main)
{
  ListBase *lbarray[MAX_LIBARRAY];
  int base_count, i;

  base_count = set_listbasepointers(main, lbarray);

  for (i = 0; i < base_count; i++) {
    ListBase *lb = lbarray[i];
    ID *id;

    for (id = lb->first; id; id = id->next) {
      if (id->override_library) {
        id->override_library->reference = newlibadr_us(
            fd, id->lib, id->override_library->reference);
        id->override_library->storage = newlibadr_us(fd, id->lib, id->override_library->storage);
      }
    }
  }
}

static void direct_link_id_override_property_operation_cb(FileData *fd, void *data)
{
  IDOverrideLibraryPropertyOperation *opop = data;

  opop->subitem_reference_name = newdataadr(fd, opop->subitem_reference_name);
  opop->subitem_local_name = newdataadr(fd, opop->subitem_local_name);
}

static void direct_link_id_override_property_cb(FileData *fd, void *data)
{
  IDOverrideLibraryProperty *op = data;

  op->rna_path = newdataadr(fd, op->rna_path);
  link_list_ex(fd, &op->operations, direct_link_id_override_property_operation_cb);
}

static void direct_link_id(FileData *fd, ID *id)
{
  /*link direct data of ID properties*/
  if (id->properties) {
    id->properties = newdataadr(fd, id->properties);
    /* this case means the data was written incorrectly, it should not happen */
    IDP_DirectLinkGroup_OrFree(&id->properties, (fd->flags & FD_FLAGS_SWITCH_ENDIAN), fd);
  }
  id->py_instance = NULL;

  /* That way data-lock reading not going through main read_libblock()
   * function are still in a clear tag state.
   * (glowering at certain nodetree fake data-lock here...). */
  id->tag = 0;

  /* Link direct data of overrides. */
  if (id->override_library) {
    id->override_library = newdataadr(fd, id->override_library);
    link_list_ex(fd, &id->override_library->properties, direct_link_id_override_property_cb);
  }

  DrawDataList *drawdata = DRW_drawdatalist_from_id(id);
  if (drawdata) {
    BLI_listbase_clear((ListBase *)drawdata);
  }
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Read CurveMapping
 * \{ */

/* cuma itself has been read! */
static void direct_link_curvemapping(FileData *fd, CurveMapping *cumap)
{
  int a;

  /* flag seems to be able to hang? Maybe old files... not bad to clear anyway */
  cumap->flag &= ~CUMA_PREMULLED;

  for (a = 0; a < CM_TOT; a++) {
    cumap->cm[a].curve = newdataadr(fd, cumap->cm[a].curve);
    cumap->cm[a].table = NULL;
    cumap->cm[a].premultable = NULL;
  }
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Read ID: Brush
 * \{ */

/* library brush linking after fileread */
static void lib_link_brush(FileData *fd, Main *main)
{
  /* only link ID pointers */
  for (Brush *brush = main->brushes.first; brush; brush = brush->id.next) {
    if (brush->id.tag & LIB_TAG_NEED_LINK) {
      IDP_LibLinkProperty(brush->id.properties, fd);

      /* brush->(mask_)mtex.obj is ignored on purpose? */
      brush->mtex.tex = newlibadr_us(fd, brush->id.lib, brush->mtex.tex);
      brush->mask_mtex.tex = newlibadr_us(fd, brush->id.lib, brush->mask_mtex.tex);
      brush->clone.image = newlibadr(fd, brush->id.lib, brush->clone.image);
      brush->toggle_brush = newlibadr(fd, brush->id.lib, brush->toggle_brush);
      brush->paint_curve = newlibadr_us(fd, brush->id.lib, brush->paint_curve);

      /* link default grease pencil palette */
      if (brush->gpencil_settings != NULL) {
        if (brush->gpencil_settings->flag & GP_BRUSH_MATERIAL_PINNED) {
          brush->gpencil_settings->material = newlibadr_us(
              fd, brush->id.lib, brush->gpencil_settings->material);

          if (!brush->gpencil_settings->material) {
            brush->gpencil_settings->flag &= ~GP_BRUSH_MATERIAL_PINNED;
          }
        }
        else {
          brush->gpencil_settings->material = NULL;
        }
      }

      brush->id.tag &= ~LIB_TAG_NEED_LINK;
    }
  }
}

static void direct_link_brush(FileData *fd, Brush *brush)
{
  /* brush itself has been read */

  /* fallof curve */
  brush->curve = newdataadr(fd, brush->curve);

  brush->gradient = newdataadr(fd, brush->gradient);

  if (brush->curve) {
    direct_link_curvemapping(fd, brush->curve);
  }
  else {
    BKE_brush_curve_preset(brush, CURVE_PRESET_SHARP);
  }

  /* grease pencil */
  brush->gpencil_settings = newdataadr(fd, brush->gpencil_settings);
  if (brush->gpencil_settings != NULL) {
    brush->gpencil_settings->curve_sensitivity = newdataadr(
        fd, brush->gpencil_settings->curve_sensitivity);
    brush->gpencil_settings->curve_strength = newdataadr(fd,
                                                         brush->gpencil_settings->curve_strength);
    brush->gpencil_settings->curve_jitter = newdataadr(fd, brush->gpencil_settings->curve_jitter);

    if (brush->gpencil_settings->curve_sensitivity) {
      direct_link_curvemapping(fd, brush->gpencil_settings->curve_sensitivity);
    }

    if (brush->gpencil_settings->curve_strength) {
      direct_link_curvemapping(fd, brush->gpencil_settings->curve_strength);
    }

    if (brush->gpencil_settings->curve_jitter) {
      direct_link_curvemapping(fd, brush->gpencil_settings->curve_jitter);
    }
  }

  brush->preview = NULL;
  brush->icon_imbuf = NULL;
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Read ID: Palette
 * \{ */

static void lib_link_palette(FileData *fd, Main *main)
{
  /* only link ID pointers */
  for (Palette *palette = main->palettes.first; palette; palette = palette->id.next) {
    if (palette->id.tag & LIB_TAG_NEED_LINK) {
      IDP_LibLinkProperty(palette->id.properties, fd);

      palette->id.tag &= ~LIB_TAG_NEED_LINK;
    }
  }
}

static void direct_link_palette(FileData *fd, Palette *palette)
{

  /* palette itself has been read */
  link_list(fd, &palette->colors);
}

static void lib_link_paint_curve(FileData *fd, Main *main)
{
  /* only link ID pointers */
  for (PaintCurve *pc = main->paintcurves.first; pc; pc = pc->id.next) {
    if (pc->id.tag & LIB_TAG_NEED_LINK) {
      IDP_LibLinkProperty(pc->id.properties, fd);

      pc->id.tag &= ~LIB_TAG_NEED_LINK;
    }
  }
}

static void direct_link_paint_curve(FileData *fd, PaintCurve *pc)
{
  pc->points = newdataadr(fd, pc->points);
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Read PackedFile
 * \{ */

static PackedFile *direct_link_packedfile(FileData *fd, PackedFile *oldpf)
{
  PackedFile *pf = newpackedadr(fd, oldpf);

  if (pf) {
    pf->data = newpackedadr(fd, pf->data);
  }

  return pf;
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Read Animation (legacy for version patching)
 * \{ */

// XXX deprecated - old animation system
static void lib_link_ipo(FileData *fd, Main *main)
{
  Ipo *ipo;

  for (ipo = main->ipo.first; ipo; ipo = ipo->id.next) {
    if (ipo->id.tag & LIB_TAG_NEED_LINK) {
      IpoCurve *icu;
      for (icu = ipo->curve.first; icu; icu = icu->next) {
        if (icu->driver) {
          icu->driver->ob = newlibadr(fd, ipo->id.lib, icu->driver->ob);
        }
      }
      ipo->id.tag &= ~LIB_TAG_NEED_LINK;
    }
  }
}

// XXX deprecated - old animation system
static void direct_link_ipo(FileData *fd, Ipo *ipo)
{
  IpoCurve *icu;

  link_list(fd, &(ipo->curve));

  for (icu = ipo->curve.first; icu; icu = icu->next) {
    icu->bezt = newdataadr(fd, icu->bezt);
    icu->bp = newdataadr(fd, icu->bp);
    icu->driver = newdataadr(fd, icu->driver);
  }
}

// XXX deprecated - old animation system
static void lib_link_nlastrips(FileData *fd, ID *id, ListBase *striplist)
{
  bActionStrip *strip;
  bActionModifier *amod;

  for (strip = striplist->first; strip; strip = strip->next) {
    strip->object = newlibadr(fd, id->lib, strip->object);
    strip->act = newlibadr_us(fd, id->lib, strip->act);
    strip->ipo = newlibadr(fd, id->lib, strip->ipo);
    for (amod = strip->modifiers.first; amod; amod = amod->next) {
      amod->ob = newlibadr(fd, id->lib, amod->ob);
    }
  }
}

// XXX deprecated - old animation system
static void direct_link_nlastrips(FileData *fd, ListBase *strips)
{
  bActionStrip *strip;

  link_list(fd, strips);

  for (strip = strips->first; strip; strip = strip->next) {
    link_list(fd, &strip->modifiers);
  }
}

// XXX deprecated - old animation system
static void lib_link_constraint_channels(FileData *fd, ID *id, ListBase *chanbase)
{
  bConstraintChannel *chan;

  for (chan = chanbase->first; chan; chan = chan->next) {
    chan->ipo = newlibadr_us(fd, id->lib, chan->ipo);
  }
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Read ID: Action
 * \{ */

static void lib_link_fmodifiers(FileData *fd, ID *id, ListBase *list)
{
  FModifier *fcm;

  for (fcm = list->first; fcm; fcm = fcm->next) {
    /* data for specific modifiers */
    switch (fcm->type) {
      case FMODIFIER_TYPE_PYTHON: {
        FMod_Python *data = (FMod_Python *)fcm->data;
        data->script = newlibadr(fd, id->lib, data->script);

        break;
      }
    }
  }
}

static void lib_link_fcurves(FileData *fd, ID *id, ListBase *list)
{
  FCurve *fcu;

  if (list == NULL) {
    return;
  }

  /* relink ID-block references... */
  for (fcu = list->first; fcu; fcu = fcu->next) {
    /* driver data */
    if (fcu->driver) {
      ChannelDriver *driver = fcu->driver;
      DriverVar *dvar;

      for (dvar = driver->variables.first; dvar; dvar = dvar->next) {
        DRIVER_TARGETS_LOOPER_BEGIN (dvar) {
          /* only relink if still used */
          if (tarIndex < dvar->num_targets) {
            dtar->id = newlibadr(fd, id->lib, dtar->id);
          }
          else {
            dtar->id = NULL;
          }
        }
        DRIVER_TARGETS_LOOPER_END;
      }
    }

    /* modifiers */
    lib_link_fmodifiers(fd, id, &fcu->modifiers);
  }
}

/* NOTE: this assumes that link_list has already been called on the list */
static void direct_link_fmodifiers(FileData *fd, ListBase *list, FCurve *curve)
{
  FModifier *fcm;

  for (fcm = list->first; fcm; fcm = fcm->next) {
    /* relink general data */
    fcm->data = newdataadr(fd, fcm->data);
    fcm->curve = curve;

    /* do relinking of data for specific types */
    switch (fcm->type) {
      case FMODIFIER_TYPE_GENERATOR: {
        FMod_Generator *data = (FMod_Generator *)fcm->data;

        data->coefficients = newdataadr(fd, data->coefficients);

        if (fd->flags & FD_FLAGS_SWITCH_ENDIAN) {
          BLI_endian_switch_float_array(data->coefficients, data->arraysize);
        }

        break;
      }
      case FMODIFIER_TYPE_ENVELOPE: {
        FMod_Envelope *data = (FMod_Envelope *)fcm->data;

        data->data = newdataadr(fd, data->data);

        break;
      }
      case FMODIFIER_TYPE_PYTHON: {
        FMod_Python *data = (FMod_Python *)fcm->data;

        data->prop = newdataadr(fd, data->prop);
        IDP_DirectLinkGroup_OrFree(&data->prop, (fd->flags & FD_FLAGS_SWITCH_ENDIAN), fd);

        break;
      }
    }
  }
}

/* NOTE: this assumes that link_list has already been called on the list */
static void direct_link_fcurves(FileData *fd, ListBase *list)
{
  FCurve *fcu;

  /* link F-Curve data to F-Curve again (non ID-libs) */
  for (fcu = list->first; fcu; fcu = fcu->next) {
    /* curve data */
    fcu->bezt = newdataadr(fd, fcu->bezt);
    fcu->fpt = newdataadr(fd, fcu->fpt);

    /* rna path */
    fcu->rna_path = newdataadr(fd, fcu->rna_path);

    /* group */
    fcu->grp = newdataadr(fd, fcu->grp);

    /* clear disabled flag - allows disabled drivers to be tried again ([#32155]),
     * but also means that another method for "reviving disabled F-Curves" exists
     */
    fcu->flag &= ~FCURVE_DISABLED;

    /* driver */
    fcu->driver = newdataadr(fd, fcu->driver);
    if (fcu->driver) {
      ChannelDriver *driver = fcu->driver;
      DriverVar *dvar;

      /* Compiled expression data will need to be regenerated
       * (old pointer may still be set here). */
      driver->expr_comp = NULL;
      driver->expr_simple = NULL;

      /* give the driver a fresh chance - the operating environment may be different now
       * (addons, etc. may be different) so the driver namespace may be sane now [#32155]
       */
      driver->flag &= ~DRIVER_FLAG_INVALID;

      /* relink variables, targets and their paths */
      link_list(fd, &driver->variables);
      for (dvar = driver->variables.first; dvar; dvar = dvar->next) {
        DRIVER_TARGETS_LOOPER_BEGIN (dvar) {
          /* only relink the targets being used */
          if (tarIndex < dvar->num_targets) {
            dtar->rna_path = newdataadr(fd, dtar->rna_path);
          }
          else {
            dtar->rna_path = NULL;
          }
        }
        DRIVER_TARGETS_LOOPER_END;
      }
    }

    /* modifiers */
    link_list(fd, &fcu->modifiers);
    direct_link_fmodifiers(fd, &fcu->modifiers, fcu);
  }
}

static void lib_link_action(FileData *fd, Main *main)
{
  for (bAction *act = main->actions.first; act; act = act->id.next) {
    if (act->id.tag & LIB_TAG_NEED_LINK) {
      IDP_LibLinkProperty(act->id.properties, fd);

      // XXX deprecated - old animation system <<<
      for (bActionChannel *chan = act->chanbase.first; chan; chan = chan->next) {
        chan->ipo = newlibadr_us(fd, act->id.lib, chan->ipo);
        lib_link_constraint_channels(fd, &act->id, &chan->constraintChannels);
      }
      // >>> XXX deprecated - old animation system

      lib_link_fcurves(fd, &act->id, &act->curves);

      for (TimeMarker *marker = act->markers.first; marker; marker = marker->next) {
        if (marker->camera) {
          marker->camera = newlibadr(fd, act->id.lib, marker->camera);
        }
      }

      act->id.tag &= ~LIB_TAG_NEED_LINK;
    }
  }
}

static void direct_link_action(FileData *fd, bAction *act)
{
  bActionChannel *achan;  // XXX deprecated - old animation system
  bActionGroup *agrp;

  link_list(fd, &act->curves);
  link_list(fd, &act->chanbase);  // XXX deprecated - old animation system
  link_list(fd, &act->groups);
  link_list(fd, &act->markers);

  // XXX deprecated - old animation system <<<
  for (achan = act->chanbase.first; achan; achan = achan->next) {
    achan->grp = newdataadr(fd, achan->grp);

    link_list(fd, &achan->constraintChannels);
  }
  // >>> XXX deprecated - old animation system

  direct_link_fcurves(fd, &act->curves);

  for (agrp = act->groups.first; agrp; agrp = agrp->next) {
    agrp->channels.first = newdataadr(fd, agrp->channels.first);
    agrp->channels.last = newdataadr(fd, agrp->channels.last);
  }
}

static void lib_link_nladata_strips(FileData *fd, ID *id, ListBase *list)
{
  NlaStrip *strip;

  for (strip = list->first; strip; strip = strip->next) {
    /* check strip's children */
    lib_link_nladata_strips(fd, id, &strip->strips);

    /* check strip's F-Curves */
    lib_link_fcurves(fd, id, &strip->fcurves);

    /* reassign the counted-reference to action */
    strip->act = newlibadr_us(fd, id->lib, strip->act);

    /* fix action id-root (i.e. if it comes from a pre 2.57 .blend file) */
    if ((strip->act) && (strip->act->idroot == 0)) {
      strip->act->idroot = GS(id->name);
    }
  }
}

static void lib_link_nladata(FileData *fd, ID *id, ListBase *list)
{
  NlaTrack *nlt;

  /* we only care about the NLA strips inside the tracks */
  for (nlt = list->first; nlt; nlt = nlt->next) {
    lib_link_nladata_strips(fd, id, &nlt->strips);
  }
}

/* This handles Animato NLA-Strips linking
 * NOTE: this assumes that link_list has already been called on the list
 */
static void direct_link_nladata_strips(FileData *fd, ListBase *list)
{
  NlaStrip *strip;

  for (strip = list->first; strip; strip = strip->next) {
    /* strip's child strips */
    link_list(fd, &strip->strips);
    direct_link_nladata_strips(fd, &strip->strips);

    /* strip's F-Curves */
    link_list(fd, &strip->fcurves);
    direct_link_fcurves(fd, &strip->fcurves);

    /* strip's F-Modifiers */
    link_list(fd, &strip->modifiers);
    direct_link_fmodifiers(fd, &strip->modifiers, NULL);
  }
}

/* NOTE: this assumes that link_list has already been called on the list */
static void direct_link_nladata(FileData *fd, ListBase *list)
{
  NlaTrack *nlt;

  for (nlt = list->first; nlt; nlt = nlt->next) {
    /* relink list of strips */
    link_list(fd, &nlt->strips);

    /* relink strip data */
    direct_link_nladata_strips(fd, &nlt->strips);
  }
}

/* ------- */

static void lib_link_keyingsets(FileData *fd, ID *id, ListBase *list)
{
  KeyingSet *ks;
  KS_Path *ksp;

  /* here, we're only interested in the ID pointer stored in some of the paths */
  for (ks = list->first; ks; ks = ks->next) {
    for (ksp = ks->paths.first; ksp; ksp = ksp->next) {
      ksp->id = newlibadr(fd, id->lib, ksp->id);
    }
  }
}

/* NOTE: this assumes that link_list has already been called on the list */
static void direct_link_keyingsets(FileData *fd, ListBase *list)
{
  KeyingSet *ks;
  KS_Path *ksp;

  /* link KeyingSet data to KeyingSet again (non ID-libs) */
  for (ks = list->first; ks; ks = ks->next) {
    /* paths */
    link_list(fd, &ks->paths);

    for (ksp = ks->paths.first; ksp; ksp = ksp->next) {
      /* rna path */
      ksp->rna_path = newdataadr(fd, ksp->rna_path);
    }
  }
}

/* ------- */

static void lib_link_animdata(FileData *fd, ID *id, AnimData *adt)
{
  if (adt == NULL) {
    return;
  }

  /* link action data */
  adt->action = newlibadr_us(fd, id->lib, adt->action);
  adt->tmpact = newlibadr_us(fd, id->lib, adt->tmpact);

  /* fix action id-roots (i.e. if they come from a pre 2.57 .blend file) */
  if ((adt->action) && (adt->action->idroot == 0)) {
    adt->action->idroot = GS(id->name);
  }
  if ((adt->tmpact) && (adt->tmpact->idroot == 0)) {
    adt->tmpact->idroot = GS(id->name);
  }

  /* link drivers */
  lib_link_fcurves(fd, id, &adt->drivers);

  /* overrides don't have lib-link for now, so no need to do anything */

  /* link NLA-data */
  lib_link_nladata(fd, id, &adt->nla_tracks);
}

static void direct_link_animdata(FileData *fd, AnimData *adt)
{
  /* NOTE: must have called newdataadr already before doing this... */
  if (adt == NULL) {
    return;
  }

  /* link drivers */
  link_list(fd, &adt->drivers);
  direct_link_fcurves(fd, &adt->drivers);
  adt->driver_array = NULL;

  /* link overrides */
  // TODO...

  /* link NLA-data */
  link_list(fd, &adt->nla_tracks);
  direct_link_nladata(fd, &adt->nla_tracks);

  /* relink active track/strip - even though strictly speaking this should only be used
   * if we're in 'tweaking mode', we need to be able to have this loaded back for
   * undo, but also since users may not exit tweakmode before saving (#24535)
   */
  // TODO: it's not really nice that anyone should be able to save the file in this
  //      state, but it's going to be too hard to enforce this single case...
  adt->act_track = newdataadr(fd, adt->act_track);
  adt->actstrip = newdataadr(fd, adt->actstrip);
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Read ID: CacheFiles
 * \{ */

static void lib_link_cachefiles(FileData *fd, Main *bmain)
{
  /* only link ID pointers */
  for (CacheFile *cache_file = bmain->cachefiles.first; cache_file;
       cache_file = cache_file->id.next) {
    if (cache_file->id.tag & LIB_TAG_NEED_LINK) {
      IDP_LibLinkProperty(cache_file->id.properties, fd);
      lib_link_animdata(fd, &cache_file->id, cache_file->adt);

      cache_file->id.tag &= ~LIB_TAG_NEED_LINK;
    }
  }
}

static void direct_link_cachefile(FileData *fd, CacheFile *cache_file)
{
  BLI_listbase_clear(&cache_file->object_paths);
  cache_file->handle = NULL;
  cache_file->handle_filepath[0] = '\0';
  cache_file->handle_readers = NULL;

  /* relink animdata */
  cache_file->adt = newdataadr(fd, cache_file->adt);
  direct_link_animdata(fd, cache_file->adt);
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Read ID: WorkSpace
 * \{ */

static void lib_link_workspaces(FileData *fd, Main *bmain)
{
  for (WorkSpace *workspace = bmain->workspaces.first; workspace; workspace = workspace->id.next) {
    ListBase *layouts = BKE_workspace_layouts_get(workspace);
    ID *id = (ID *)workspace;

    if ((id->tag & LIB_TAG_NEED_LINK) == 0) {
      continue;
    }
    IDP_LibLinkProperty(id->properties, fd);
    id_us_ensure_real(id);

    for (WorkSpaceLayout *layout = layouts->first, *layout_next; layout; layout = layout_next) {
      layout->screen = newlibadr_us(fd, id->lib, layout->screen);

      layout_next = layout->next;
      if (layout->screen) {
        if (ID_IS_LINKED(id)) {
          layout->screen->winid = 0;
          if (layout->screen->temp) {
            /* delete temp layouts when appending */
            BKE_workspace_layout_remove(bmain, workspace, layout);
          }
        }
      }
    }

    id->tag &= ~LIB_TAG_NEED_LINK;
  }
}

static void direct_link_workspace(FileData *fd, WorkSpace *workspace, const Main *main)
{
  link_list(fd, BKE_workspace_layouts_get(workspace));
  link_list(fd, &workspace->hook_layout_relations);
  link_list(fd, &workspace->owner_ids);
  link_list(fd, &workspace->tools);

  for (WorkSpaceDataRelation *relation = workspace->hook_layout_relations.first; relation;
       relation = relation->next) {
    relation->parent = newglobadr(
        fd, relation->parent); /* data from window - need to access through global oldnew-map */
    relation->value = newdataadr(fd, relation->value);
  }

  /* Same issue/fix as in direct_link_workspace_link_scene_data: Can't read workspace data
   * when reading windows, so have to update windows after/when reading workspaces. */
  for (wmWindowManager *wm = main->wm.first; wm; wm = wm->id.next) {
    for (wmWindow *win = wm->windows.first; win; win = win->next) {
      WorkSpaceLayout *act_layout = newdataadr(
          fd, BKE_workspace_active_layout_get(win->workspace_hook));
      if (act_layout) {
        BKE_workspace_active_layout_set(win->workspace_hook, act_layout);
      }
    }
  }

  for (bToolRef *tref = workspace->tools.first; tref; tref = tref->next) {
    tref->runtime = NULL;
    tref->properties = newdataadr(fd, tref->properties);
    IDP_DirectLinkGroup_OrFree(&tref->properties, (fd->flags & FD_FLAGS_SWITCH_ENDIAN), fd);
  }

  workspace->status_text = NULL;
}

static void lib_link_workspace_instance_hook(FileData *fd, WorkSpaceInstanceHook *hook, ID *id)
{
  WorkSpace *workspace = BKE_workspace_active_get(hook);
  BKE_workspace_active_set(hook, newlibadr(fd, id->lib, workspace));
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Read ID: Node Tree
 * \{ */

/* Single node tree (also used for material/scene trees), ntree is not NULL */
static void lib_link_ntree(FileData *fd, ID *id, bNodeTree *ntree)
{
  IDP_LibLinkProperty(ntree->id.properties, fd);
  lib_link_animdata(fd, &ntree->id, ntree->adt);

  ntree->gpd = newlibadr_us(fd, id->lib, ntree->gpd);

  for (bNode *node = ntree->nodes.first; node; node = node->next) {
    /* Link ID Properties -- and copy this comment EXACTLY for easy finding
     * of library blocks that implement this.*/
    IDP_LibLinkProperty(node->prop, fd);

    node->id = newlibadr_us(fd, id->lib, node->id);

    for (bNodeSocket *sock = node->inputs.first; sock; sock = sock->next) {
      IDP_LibLinkProperty(sock->prop, fd);
    }
    for (bNodeSocket *sock = node->outputs.first; sock; sock = sock->next) {
      IDP_LibLinkProperty(sock->prop, fd);
    }
  }

  for (bNodeSocket *sock = ntree->inputs.first; sock; sock = sock->next) {
    IDP_LibLinkProperty(sock->prop, fd);
  }
  for (bNodeSocket *sock = ntree->outputs.first; sock; sock = sock->next) {
    IDP_LibLinkProperty(sock->prop, fd);
  }

  /* Set node->typeinfo pointers. This is done in lib linking, after the
   * first versioning that can change types still without functions that
   * update the typeinfo pointers. Versioning after lib linking needs
   * these top be valid. */
  ntreeSetTypes(NULL, ntree);

  /* For nodes with static socket layout, add/remove sockets as needed
   * to match the static layout. */
  if (fd->memfile == NULL) {
    for (bNode *node = ntree->nodes.first; node; node = node->next) {
      node_verify_socket_templates(ntree, node);
    }
  }
}

/* library ntree linking after fileread */
static void lib_link_nodetree(FileData *fd, Main *main)
{
  /* only link ID pointers */
  for (bNodeTree *ntree = main->nodetrees.first; ntree; ntree = ntree->id.next) {
    if (ntree->id.tag & LIB_TAG_NEED_LINK) {
      lib_link_ntree(fd, &ntree->id, ntree);

      ntree->id.tag &= ~LIB_TAG_NEED_LINK;
    }
  }
}

static void direct_link_node_socket(FileData *fd, bNodeSocket *sock)
{
  sock->prop = newdataadr(fd, sock->prop);
  IDP_DirectLinkGroup_OrFree(&sock->prop, (fd->flags & FD_FLAGS_SWITCH_ENDIAN), fd);

  sock->link = newdataadr(fd, sock->link);
  sock->typeinfo = NULL;
  sock->storage = newdataadr(fd, sock->storage);
  sock->default_value = newdataadr(fd, sock->default_value);
  sock->cache = NULL;
}

/* ntree itself has been read! */
static void direct_link_nodetree(FileData *fd, bNodeTree *ntree)
{
  /* note: writing and reading goes in sync, for speed */
  bNode *node;
  bNodeSocket *sock;
  bNodeLink *link;

  ntree->init = 0; /* to set callbacks and force setting types */
  ntree->is_updating = false;
  ntree->typeinfo = NULL;
  ntree->interface_type = NULL;

  ntree->progress = NULL;
  ntree->execdata = NULL;

  ntree->adt = newdataadr(fd, ntree->adt);
  direct_link_animdata(fd, ntree->adt);

  ntree->id.recalc &= ~ID_RECALC_ALL;

  link_list(fd, &ntree->nodes);
  for (node = ntree->nodes.first; node; node = node->next) {
    node->typeinfo = NULL;

    link_list(fd, &node->inputs);
    link_list(fd, &node->outputs);

    node->prop = newdataadr(fd, node->prop);
    IDP_DirectLinkGroup_OrFree(&node->prop, (fd->flags & FD_FLAGS_SWITCH_ENDIAN), fd);

    link_list(fd, &node->internal_links);
    for (link = node->internal_links.first; link; link = link->next) {
      link->fromnode = newdataadr(fd, link->fromnode);
      link->fromsock = newdataadr(fd, link->fromsock);
      link->tonode = newdataadr(fd, link->tonode);
      link->tosock = newdataadr(fd, link->tosock);
    }

    if (node->type == CMP_NODE_MOVIEDISTORTION) {
      node->storage = newmclipadr(fd, node->storage);
    }
    else {
      node->storage = newdataadr(fd, node->storage);
    }

    if (node->storage) {
      /* could be handlerized at some point */
      switch (node->type) {
        case SH_NODE_CURVE_VEC:
        case SH_NODE_CURVE_RGB:
        case CMP_NODE_TIME:
        case CMP_NODE_CURVE_VEC:
        case CMP_NODE_CURVE_RGB:
        case CMP_NODE_HUECORRECT:
        case TEX_NODE_CURVE_RGB:
        case TEX_NODE_CURVE_TIME: {
          direct_link_curvemapping(fd, node->storage);
          break;
        }
        case SH_NODE_SCRIPT: {
          NodeShaderScript *nss = (NodeShaderScript *)node->storage;
          nss->bytecode = newdataadr(fd, nss->bytecode);
          break;
        }
        case SH_NODE_TEX_POINTDENSITY: {
          NodeShaderTexPointDensity *npd = (NodeShaderTexPointDensity *)node->storage;
          memset(&npd->pd, 0, sizeof(npd->pd));
          break;
        }
        case SH_NODE_TEX_IMAGE: {
          NodeTexImage *tex = (NodeTexImage *)node->storage;
          tex->iuser.ok = 1;
          tex->iuser.scene = NULL;
          break;
        }
        case SH_NODE_TEX_ENVIRONMENT: {
          NodeTexEnvironment *tex = (NodeTexEnvironment *)node->storage;
          tex->iuser.ok = 1;
          tex->iuser.scene = NULL;
          break;
        }
        case CMP_NODE_IMAGE:
        case CMP_NODE_R_LAYERS:
        case CMP_NODE_VIEWER:
        case CMP_NODE_SPLITVIEWER: {
          ImageUser *iuser = node->storage;
          iuser->ok = 1;
          iuser->scene = NULL;
          break;
        }
        case CMP_NODE_CRYPTOMATTE: {
          NodeCryptomatte *nc = (NodeCryptomatte *)node->storage;
          nc->matte_id = newdataadr(fd, nc->matte_id);
          break;
        }
        case TEX_NODE_IMAGE: {
          ImageUser *iuser = node->storage;
          iuser->ok = 1;
          iuser->scene = NULL;
          break;
        }
        default:
          break;
      }
    }
  }
  link_list(fd, &ntree->links);

  /* and we connect the rest */
  for (node = ntree->nodes.first; node; node = node->next) {
    node->parent = newdataadr(fd, node->parent);
    node->lasty = 0;

    for (sock = node->inputs.first; sock; sock = sock->next) {
      direct_link_node_socket(fd, sock);
    }
    for (sock = node->outputs.first; sock; sock = sock->next) {
      direct_link_node_socket(fd, sock);
    }
  }

  /* interface socket lists */
  link_list(fd, &ntree->inputs);
  link_list(fd, &ntree->outputs);
  for (sock = ntree->inputs.first; sock; sock = sock->next) {
    direct_link_node_socket(fd, sock);
  }
  for (sock = ntree->outputs.first; sock; sock = sock->next) {
    direct_link_node_socket(fd, sock);
  }

  for (link = ntree->links.first; link; link = link->next) {
    link->fromnode = newdataadr(fd, link->fromnode);
    link->tonode = newdataadr(fd, link->tonode);
    link->fromsock = newdataadr(fd, link->fromsock);
    link->tosock = newdataadr(fd, link->tosock);
  }

#if 0
  if (ntree->previews) {
    bNodeInstanceHash *new_previews = BKE_node_instance_hash_new("node previews");
    bNodeInstanceHashIterator iter;

    NODE_INSTANCE_HASH_ITER(iter, ntree->previews) {
      bNodePreview *preview = BKE_node_instance_hash_iterator_get_value(&iter);
      if (preview) {
        bNodePreview *new_preview = newimaadr(fd, preview);
        if (new_preview) {
          bNodeInstanceKey key = BKE_node_instance_hash_iterator_get_key(&iter);
          BKE_node_instance_hash_insert(new_previews, key, new_preview);
        }
      }
    }
    BKE_node_instance_hash_free(ntree->previews, NULL);
    ntree->previews = new_previews;
  }
#else
  /* XXX TODO */
  ntree->previews = NULL;
#endif

  /* type verification is in lib-link */
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Read ID: Armature
 * \{ */

/* temp struct used to transport needed info to lib_link_constraint_cb() */
typedef struct tConstraintLinkData {
  FileData *fd;
  ID *id;
} tConstraintLinkData;
/* callback function used to relink constraint ID-links */
static void lib_link_constraint_cb(bConstraint *UNUSED(con),
                                   ID **idpoin,
                                   bool is_reference,
                                   void *userdata)
{
  tConstraintLinkData *cld = (tConstraintLinkData *)userdata;

  /* for reference types, we need to increment the usercounts on load... */
  if (is_reference) {
    /* reference type - with usercount */
    *idpoin = newlibadr_us(cld->fd, cld->id->lib, *idpoin);
  }
  else {
    /* target type - no usercount needed */
    *idpoin = newlibadr(cld->fd, cld->id->lib, *idpoin);
  }
}

static void lib_link_constraints(FileData *fd, ID *id, ListBase *conlist)
{
  tConstraintLinkData cld;
  bConstraint *con;

  /* legacy fixes */
  for (con = conlist->first; con; con = con->next) {
    /* patch for error introduced by changing constraints (dunno how) */
    /* if con->data type changes, dna cannot resolve the pointer! (ton) */
    if (con->data == NULL) {
      con->type = CONSTRAINT_TYPE_NULL;
    }
    /* own ipo, all constraints have it */
    con->ipo = newlibadr_us(fd, id->lib, con->ipo);  // XXX deprecated - old animation system

    /* If linking from a library, clear 'local' library override flag. */
    if (id->lib != NULL) {
      con->flag &= ~CONSTRAINT_OVERRIDE_LIBRARY_LOCAL;
    }
  }

  /* relink all ID-blocks used by the constraints */
  cld.fd = fd;
  cld.id = id;

  BKE_constraints_id_loop(conlist, lib_link_constraint_cb, &cld);
}

static void direct_link_constraints(FileData *fd, ListBase *lb)
{
  bConstraint *con;

  link_list(fd, lb);
  for (con = lb->first; con; con = con->next) {
    con->data = newdataadr(fd, con->data);

    switch (con->type) {
      case CONSTRAINT_TYPE_PYTHON: {
        bPythonConstraint *data = con->data;

        link_list(fd, &data->targets);

        data->prop = newdataadr(fd, data->prop);
        IDP_DirectLinkGroup_OrFree(&data->prop, (fd->flags & FD_FLAGS_SWITCH_ENDIAN), fd);
        break;
      }
      case CONSTRAINT_TYPE_ARMATURE: {
        bArmatureConstraint *data = con->data;

        link_list(fd, &data->targets);

        break;
      }
      case CONSTRAINT_TYPE_SPLINEIK: {
        bSplineIKConstraint *data = con->data;

        data->points = newdataadr(fd, data->points);
        break;
      }
      case CONSTRAINT_TYPE_KINEMATIC: {
        bKinematicConstraint *data = con->data;

        con->lin_error = 0.f;
        con->rot_error = 0.f;

        /* version patch for runtime flag, was not cleared in some case */
        data->flag &= ~CONSTRAINT_IK_AUTO;
        break;
      }
      case CONSTRAINT_TYPE_CHILDOF: {
        /* XXX version patch, in older code this flag wasn't always set, and is inherent to type */
        if (con->ownspace == CONSTRAINT_SPACE_POSE) {
          con->flag |= CONSTRAINT_SPACEONCE;
        }
        break;
      }
      case CONSTRAINT_TYPE_TRANSFORM_CACHE: {
        bTransformCacheConstraint *data = con->data;
        data->reader = NULL;
        data->reader_object_path[0] = '\0';
      }
    }
  }
}

static void lib_link_pose(FileData *fd, Main *bmain, Object *ob, bPose *pose)
{
  bArmature *arm = ob->data;

  if (!pose || !arm) {
    return;
  }

  /* always rebuild to match proxy or lib changes, but on Undo */
  bool rebuild = false;

  if (fd->memfile == NULL) {
    if (ob->proxy || ob->id.lib != arm->id.lib) {
      rebuild = true;
    }
  }

  if (ob->proxy) {
    /* sync proxy layer */
    if (pose->proxy_layer) {
      arm->layer = pose->proxy_layer;
    }

    /* sync proxy active bone */
    if (pose->proxy_act_bone[0]) {
      Bone *bone = BKE_armature_find_bone_name(arm, pose->proxy_act_bone);
      if (bone) {
        arm->act_bone = bone;
      }
    }
  }

  for (bPoseChannel *pchan = pose->chanbase.first; pchan; pchan = pchan->next) {
    lib_link_constraints(fd, (ID *)ob, &pchan->constraints);

    pchan->bone = BKE_armature_find_bone_name(arm, pchan->name);

    IDP_LibLinkProperty(pchan->prop, fd);

    pchan->custom = newlibadr_us(fd, arm->id.lib, pchan->custom);
    if (UNLIKELY(pchan->bone == NULL)) {
      rebuild = true;
    }
    else if ((ob->id.lib == NULL) && arm->id.lib) {
      /* local pose selection copied to armature, bit hackish */
      pchan->bone->flag &= ~BONE_SELECTED;
      pchan->bone->flag |= pchan->selectflag;
    }
  }

  if (rebuild) {
    DEG_id_tag_update_ex(
        bmain, &ob->id, ID_RECALC_TRANSFORM | ID_RECALC_GEOMETRY | ID_RECALC_ANIMATION);
    BKE_pose_tag_recalc(bmain, pose);
  }
}

static void lib_link_bones(FileData *fd, Bone *bone)
{
  IDP_LibLinkProperty(bone->prop, fd);

  for (Bone *curbone = bone->childbase.first; curbone; curbone = curbone->next) {
    lib_link_bones(fd, curbone);
  }
}

static void lib_link_armature(FileData *fd, Main *main)
{
  for (bArmature *arm = main->armatures.first; arm; arm = arm->id.next) {
    if (arm->id.tag & LIB_TAG_NEED_LINK) {
      IDP_LibLinkProperty(arm->id.properties, fd);
      lib_link_animdata(fd, &arm->id, arm->adt);

      for (Bone *curbone = arm->bonebase.first; curbone; curbone = curbone->next) {
        lib_link_bones(fd, curbone);
      }

      arm->id.tag &= ~LIB_TAG_NEED_LINK;
    }
  }
}

static void direct_link_bones(FileData *fd, Bone *bone)
{
  Bone *child;

  bone->parent = newdataadr(fd, bone->parent);
  bone->prop = newdataadr(fd, bone->prop);
  IDP_DirectLinkGroup_OrFree(&bone->prop, (fd->flags & FD_FLAGS_SWITCH_ENDIAN), fd);

  bone->bbone_next = newdataadr(fd, bone->bbone_next);
  bone->bbone_prev = newdataadr(fd, bone->bbone_prev);

  bone->flag &= ~BONE_DRAW_ACTIVE;

  link_list(fd, &bone->childbase);

  for (child = bone->childbase.first; child; child = child->next) {
    direct_link_bones(fd, child);
  }
}

static void direct_link_armature(FileData *fd, bArmature *arm)
{
  Bone *bone;

  link_list(fd, &arm->bonebase);
  arm->bonehash = NULL;
  arm->edbo = NULL;

  arm->adt = newdataadr(fd, arm->adt);
  direct_link_animdata(fd, arm->adt);

  for (bone = arm->bonebase.first; bone; bone = bone->next) {
    direct_link_bones(fd, bone);
  }

  arm->act_bone = newdataadr(fd, arm->act_bone);
  arm->act_edbone = NULL;

  BKE_armature_bone_hash_make(arm);
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Read ID: Camera
 * \{ */

static void lib_link_camera(FileData *fd, Main *main)
{
  for (Camera *ca = main->cameras.first; ca; ca = ca->id.next) {
    if (ca->id.tag & LIB_TAG_NEED_LINK) {
      IDP_LibLinkProperty(ca->id.properties, fd);
      lib_link_animdata(fd, &ca->id, ca->adt);

      ca->ipo = newlibadr_us(fd, ca->id.lib, ca->ipo); /* deprecated, for versioning */

      ca->dof_ob = newlibadr(fd, ca->id.lib, ca->dof_ob); /* deprecated, for versioning */
      ca->dof.focus_object = newlibadr(fd, ca->id.lib, ca->dof.focus_object);

      for (CameraBGImage *bgpic = ca->bg_images.first; bgpic; bgpic = bgpic->next) {
        bgpic->ima = newlibadr_us(fd, ca->id.lib, bgpic->ima);
        bgpic->clip = newlibadr_us(fd, ca->id.lib, bgpic->clip);
      }

      ca->id.tag &= ~LIB_TAG_NEED_LINK;
    }
  }
}

static void direct_link_camera(FileData *fd, Camera *ca)
{
  ca->adt = newdataadr(fd, ca->adt);
  direct_link_animdata(fd, ca->adt);

  link_list(fd, &ca->bg_images);

  for (CameraBGImage *bgpic = ca->bg_images.first; bgpic; bgpic = bgpic->next) {
    bgpic->iuser.ok = 1;
    bgpic->iuser.scene = NULL;
  }
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Read ID: Light
 * \{ */

static void lib_link_light(FileData *fd, Main *main)
{
  for (Light *la = main->lights.first; la; la = la->id.next) {
    if (la->id.tag & LIB_TAG_NEED_LINK) {
      IDP_LibLinkProperty(la->id.properties, fd);
      lib_link_animdata(fd, &la->id, la->adt);

      la->ipo = newlibadr_us(fd, la->id.lib, la->ipo);  // XXX deprecated - old animation system

      if (la->nodetree) {
        lib_link_ntree(fd, &la->id, la->nodetree);
        la->nodetree->id.lib = la->id.lib;
      }

      la->id.tag &= ~LIB_TAG_NEED_LINK;
    }
  }
}

static void direct_link_light(FileData *fd, Light *la)
{
  la->adt = newdataadr(fd, la->adt);
  direct_link_animdata(fd, la->adt);

  la->curfalloff = newdataadr(fd, la->curfalloff);
  if (la->curfalloff) {
    direct_link_curvemapping(fd, la->curfalloff);
  }

  la->nodetree = newdataadr(fd, la->nodetree);
  if (la->nodetree) {
    direct_link_id(fd, &la->nodetree->id);
    direct_link_nodetree(fd, la->nodetree);
  }

  la->preview = direct_link_preview_image(fd, la->preview);
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Read ID: Shape Keys
 * \{ */

void blo_do_versions_key_uidgen(Key *key)
{
  KeyBlock *block;

  key->uidgen = 1;
  for (block = key->block.first; block; block = block->next) {
    block->uid = key->uidgen++;
  }
}

static void lib_link_key(FileData *fd, Main *main)
{
  for (Key *key = main->shapekeys.first; key; key = key->id.next) {
    BLI_assert((key->id.tag & LIB_TAG_EXTERN) == 0);

    if (key->id.tag & LIB_TAG_NEED_LINK) {
      IDP_LibLinkProperty(key->id.properties, fd);
      lib_link_animdata(fd, &key->id, key->adt);

      key->ipo = newlibadr_us(fd, key->id.lib, key->ipo);  // XXX deprecated - old animation system
      key->from = newlibadr(fd, key->id.lib, key->from);

      key->id.tag &= ~LIB_TAG_NEED_LINK;
    }
  }
}

static void switch_endian_keyblock(Key *key, KeyBlock *kb)
{
  int elemsize, a, b;
  char *data;

  elemsize = key->elemsize;
  data = kb->data;

  for (a = 0; a < kb->totelem; a++) {
    const char *cp = key->elemstr;
    char *poin = data;

    while (cp[0]) {    /* cp[0] == amount */
      switch (cp[1]) { /* cp[1] = type */
        case IPO_FLOAT:
        case IPO_BPOINT:
        case IPO_BEZTRIPLE:
          b = cp[0];
          BLI_endian_switch_float_array((float *)poin, b);
          poin += sizeof(float) * b;
          break;
      }

      cp += 2;
    }
    data += elemsize;
  }
}

static void direct_link_key(FileData *fd, Key *key)
{
  KeyBlock *kb;

  link_list(fd, &(key->block));

  key->adt = newdataadr(fd, key->adt);
  direct_link_animdata(fd, key->adt);

  key->refkey = newdataadr(fd, key->refkey);

  for (kb = key->block.first; kb; kb = kb->next) {
    kb->data = newdataadr(fd, kb->data);

    if (fd->flags & FD_FLAGS_SWITCH_ENDIAN) {
      switch_endian_keyblock(key, kb);
    }
  }
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Read ID: Meta Ball
 * \{ */

static void lib_link_mball(FileData *fd, Main *main)
{
  for (MetaBall *mb = main->metaballs.first; mb; mb = mb->id.next) {
    if (mb->id.tag & LIB_TAG_NEED_LINK) {
      IDP_LibLinkProperty(mb->id.properties, fd);
      lib_link_animdata(fd, &mb->id, mb->adt);

      for (int a = 0; a < mb->totcol; a++) {
        mb->mat[a] = newlibadr_us(fd, mb->id.lib, mb->mat[a]);
      }

      mb->ipo = newlibadr_us(fd, mb->id.lib, mb->ipo);  // XXX deprecated - old animation system

      mb->id.tag &= ~LIB_TAG_NEED_LINK;
    }
  }
}

static void direct_link_mball(FileData *fd, MetaBall *mb)
{
  mb->adt = newdataadr(fd, mb->adt);
  direct_link_animdata(fd, mb->adt);

  mb->mat = newdataadr(fd, mb->mat);
  test_pointer_array(fd, (void **)&mb->mat);

  link_list(fd, &(mb->elems));

  BLI_listbase_clear(&mb->disp);
  mb->editelems = NULL;
  /*  mb->edit_elems.first= mb->edit_elems.last= NULL;*/
  mb->lastelem = NULL;
  mb->batch_cache = NULL;
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Read ID: World
 * \{ */

static void lib_link_world(FileData *fd, Main *main)
{
  for (World *wrld = main->worlds.first; wrld; wrld = wrld->id.next) {
    if (wrld->id.tag & LIB_TAG_NEED_LINK) {
      IDP_LibLinkProperty(wrld->id.properties, fd);
      lib_link_animdata(fd, &wrld->id, wrld->adt);

      wrld->ipo = newlibadr_us(
          fd, wrld->id.lib, wrld->ipo);  // XXX deprecated - old animation system

      if (wrld->nodetree) {
        lib_link_ntree(fd, &wrld->id, wrld->nodetree);
        wrld->nodetree->id.lib = wrld->id.lib;
      }

      wrld->id.tag &= ~LIB_TAG_NEED_LINK;
    }
  }
}

static void direct_link_world(FileData *fd, World *wrld)
{
  wrld->adt = newdataadr(fd, wrld->adt);
  direct_link_animdata(fd, wrld->adt);

  wrld->nodetree = newdataadr(fd, wrld->nodetree);
  if (wrld->nodetree) {
    direct_link_id(fd, &wrld->nodetree->id);
    direct_link_nodetree(fd, wrld->nodetree);
  }

  wrld->preview = direct_link_preview_image(fd, wrld->preview);
  BLI_listbase_clear(&wrld->gpumaterial);
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Read ID: VFont
 * \{ */

static void lib_link_vfont(FileData *fd, Main *main)
{
  for (VFont *vf = main->fonts.first; vf; vf = vf->id.next) {
    if (vf->id.tag & LIB_TAG_NEED_LINK) {
      IDP_LibLinkProperty(vf->id.properties, fd);

      vf->id.tag &= ~LIB_TAG_NEED_LINK;
    }
  }
}

static void direct_link_vfont(FileData *fd, VFont *vf)
{
  vf->data = NULL;
  vf->temp_pf = NULL;
  vf->packedfile = direct_link_packedfile(fd, vf->packedfile);
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Read ID: Text
 * \{ */

static void lib_link_text(FileData *fd, Main *main)
{
  for (Text *text = main->texts.first; text; text = text->id.next) {
    if (text->id.tag & LIB_TAG_NEED_LINK) {
      IDP_LibLinkProperty(text->id.properties, fd);

      text->id.tag &= ~LIB_TAG_NEED_LINK;
    }
  }
}

static void direct_link_text(FileData *fd, Text *text)
{
  TextLine *ln;

  text->name = newdataadr(fd, text->name);

  text->compiled = NULL;

#if 0
  if (text->flags & TXT_ISEXT) {
    BKE_text_reload(text);
  }
  /* else { */
#endif

  link_list(fd, &text->lines);

  text->curl = newdataadr(fd, text->curl);
  text->sell = newdataadr(fd, text->sell);

  for (ln = text->lines.first; ln; ln = ln->next) {
    ln->line = newdataadr(fd, ln->line);
    ln->format = NULL;

    if (ln->len != (int)strlen(ln->line)) {
      printf("Error loading text, line lengths differ\n");
      ln->len = strlen(ln->line);
    }
  }

  text->flags = (text->flags) & ~TXT_ISEXT;

  id_us_ensure_real(&text->id);
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Read ID: Image
 * \{ */

static void lib_link_image(FileData *fd, Main *main)
{
  for (Image *ima = main->images.first; ima; ima = ima->id.next) {
    if (ima->id.tag & LIB_TAG_NEED_LINK) {
      IDP_LibLinkProperty(ima->id.properties, fd);

      ima->id.tag &= ~LIB_TAG_NEED_LINK;
    }
  }
}

static void direct_link_image(FileData *fd, Image *ima)
{
  ImagePackedFile *imapf;

  /* for undo system, pointers could be restored */
  if (fd->imamap) {
    ima->cache = newimaadr(fd, ima->cache);
  }
  else {
    ima->cache = NULL;
  }

  /* if not restored, we keep the binded opengl index */
  if (!ima->cache) {
    ima->gpuflag = 0;
    ima->gpuframenr = INT_MAX;
    for (int i = 0; i < TEXTARGET_COUNT; i++) {
      ima->gputexture[i] = NULL;
    }
    ima->rr = NULL;
  }
  else {
    for (int i = 0; i < TEXTARGET_COUNT; i++) {
      ima->gputexture[i] = newimaadr(fd, ima->gputexture[i]);
    }
    ima->rr = newimaadr(fd, ima->rr);
  }

  /* undo system, try to restore render buffers */
  link_list(fd, &(ima->renderslots));
  if (fd->imamap) {
    LISTBASE_FOREACH (RenderSlot *, slot, &ima->renderslots) {
      slot->render = newimaadr(fd, slot->render);
    }
  }
  else {
    LISTBASE_FOREACH (RenderSlot *, slot, &ima->renderslots) {
      slot->render = NULL;
    }
    ima->last_render_slot = ima->render_slot;
  }

  link_list(fd, &(ima->views));
  link_list(fd, &(ima->packedfiles));

  if (ima->packedfiles.first) {
    for (imapf = ima->packedfiles.first; imapf; imapf = imapf->next) {
      imapf->packedfile = direct_link_packedfile(fd, imapf->packedfile);
    }
    ima->packedfile = NULL;
  }
  else {
    ima->packedfile = direct_link_packedfile(fd, ima->packedfile);
  }

  BLI_listbase_clear(&ima->anims);
  ima->preview = direct_link_preview_image(fd, ima->preview);
  ima->stereo3d_format = newdataadr(fd, ima->stereo3d_format);
  ima->ok = 1;
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Read ID: Curve
 * \{ */

static void lib_link_curve(FileData *fd, Main *main)
{
  for (Curve *cu = main->curves.first; cu; cu = cu->id.next) {
    if (cu->id.tag & LIB_TAG_NEED_LINK) {
      IDP_LibLinkProperty(cu->id.properties, fd);
      lib_link_animdata(fd, &cu->id, cu->adt);

      for (int a = 0; a < cu->totcol; a++) {
        cu->mat[a] = newlibadr_us(fd, cu->id.lib, cu->mat[a]);
      }

      cu->bevobj = newlibadr(fd, cu->id.lib, cu->bevobj);
      cu->taperobj = newlibadr(fd, cu->id.lib, cu->taperobj);
      cu->textoncurve = newlibadr(fd, cu->id.lib, cu->textoncurve);
      cu->vfont = newlibadr_us(fd, cu->id.lib, cu->vfont);
      cu->vfontb = newlibadr_us(fd, cu->id.lib, cu->vfontb);
      cu->vfonti = newlibadr_us(fd, cu->id.lib, cu->vfonti);
      cu->vfontbi = newlibadr_us(fd, cu->id.lib, cu->vfontbi);

      cu->ipo = newlibadr_us(fd, cu->id.lib, cu->ipo);  // XXX deprecated - old animation system
      cu->key = newlibadr_us(fd, cu->id.lib, cu->key);

      cu->id.tag &= ~LIB_TAG_NEED_LINK;
    }
  }
}

static void switch_endian_knots(Nurb *nu)
{
  if (nu->knotsu) {
    BLI_endian_switch_float_array(nu->knotsu, KNOTSU(nu));
  }
  if (nu->knotsv) {
    BLI_endian_switch_float_array(nu->knotsv, KNOTSV(nu));
  }
}

static void direct_link_curve(FileData *fd, Curve *cu)
{
  Nurb *nu;
  TextBox *tb;

  cu->adt = newdataadr(fd, cu->adt);
  direct_link_animdata(fd, cu->adt);

  /* Protect against integer overflow vulnerability. */
  CLAMP(cu->len_wchar, 0, INT_MAX - 4);

  cu->mat = newdataadr(fd, cu->mat);
  test_pointer_array(fd, (void **)&cu->mat);
  cu->str = newdataadr(fd, cu->str);
  cu->strinfo = newdataadr(fd, cu->strinfo);
  cu->tb = newdataadr(fd, cu->tb);

  if (cu->vfont == NULL) {
    link_list(fd, &(cu->nurb));
  }
  else {
    cu->nurb.first = cu->nurb.last = NULL;

    tb = MEM_calloc_arrayN(MAXTEXTBOX, sizeof(TextBox), "TextBoxread");
    if (cu->tb) {
      memcpy(tb, cu->tb, cu->totbox * sizeof(TextBox));
      MEM_freeN(cu->tb);
      cu->tb = tb;
    }
    else {
      cu->totbox = 1;
      cu->actbox = 1;
      cu->tb = tb;
      cu->tb[0].w = cu->linewidth;
    }
    if (cu->wordspace == 0.0f) {
      cu->wordspace = 1.0f;
    }
  }

  cu->editnurb = NULL;
  cu->editfont = NULL;
  cu->batch_cache = NULL;

  for (nu = cu->nurb.first; nu; nu = nu->next) {
    nu->bezt = newdataadr(fd, nu->bezt);
    nu->bp = newdataadr(fd, nu->bp);
    nu->knotsu = newdataadr(fd, nu->knotsu);
    nu->knotsv = newdataadr(fd, nu->knotsv);
    if (cu->vfont == NULL) {
      nu->charidx = 0;
    }

    if (fd->flags & FD_FLAGS_SWITCH_ENDIAN) {
      switch_endian_knots(nu);
    }
  }
  cu->bb = NULL;
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Read ID: Texture
 * \{ */

static void lib_link_texture(FileData *fd, Main *main)
{
  for (Tex *tex = main->textures.first; tex; tex = tex->id.next) {
    if (tex->id.tag & LIB_TAG_NEED_LINK) {
      IDP_LibLinkProperty(tex->id.properties, fd);
      lib_link_animdata(fd, &tex->id, tex->adt);

      tex->ima = newlibadr_us(fd, tex->id.lib, tex->ima);
      tex->ipo = newlibadr_us(fd, tex->id.lib, tex->ipo);  // XXX deprecated - old animation system

      if (tex->nodetree) {
        lib_link_ntree(fd, &tex->id, tex->nodetree);
        tex->nodetree->id.lib = tex->id.lib;
      }

      tex->id.tag &= ~LIB_TAG_NEED_LINK;
    }
  }
}

static void direct_link_texture(FileData *fd, Tex *tex)
{
  tex->adt = newdataadr(fd, tex->adt);
  direct_link_animdata(fd, tex->adt);

  tex->coba = newdataadr(fd, tex->coba);

  tex->nodetree = newdataadr(fd, tex->nodetree);
  if (tex->nodetree) {
    direct_link_id(fd, &tex->nodetree->id);
    direct_link_nodetree(fd, tex->nodetree);
  }

  tex->preview = direct_link_preview_image(fd, tex->preview);

  tex->iuser.ok = 1;
  tex->iuser.scene = NULL;
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Read ID: Material
 * \{ */

static void lib_link_material(FileData *fd, Main *main)
{
  for (Material *ma = main->materials.first; ma; ma = ma->id.next) {
    if (ma->id.tag & LIB_TAG_NEED_LINK) {
      IDP_LibLinkProperty(ma->id.properties, fd);
      lib_link_animdata(fd, &ma->id, ma->adt);

      ma->ipo = newlibadr_us(fd, ma->id.lib, ma->ipo);  // XXX deprecated - old animation system

      if (ma->nodetree) {
        lib_link_ntree(fd, &ma->id, ma->nodetree);
        ma->nodetree->id.lib = ma->id.lib;
      }

      /* relink grease pencil settings */
      if (ma->gp_style != NULL) {
        MaterialGPencilStyle *gp_style = ma->gp_style;
        if (gp_style->sima != NULL) {
          gp_style->sima = newlibadr_us(fd, ma->id.lib, gp_style->sima);
        }
        if (gp_style->ima != NULL) {
          gp_style->ima = newlibadr_us(fd, ma->id.lib, gp_style->ima);
        }
      }

      ma->id.tag &= ~LIB_TAG_NEED_LINK;
    }
  }
}

static void direct_link_material(FileData *fd, Material *ma)
{
  ma->adt = newdataadr(fd, ma->adt);
  direct_link_animdata(fd, ma->adt);

  ma->texpaintslot = NULL;

  ma->nodetree = newdataadr(fd, ma->nodetree);
  if (ma->nodetree) {
    direct_link_id(fd, &ma->nodetree->id);
    direct_link_nodetree(fd, ma->nodetree);
  }

  ma->preview = direct_link_preview_image(fd, ma->preview);
  BLI_listbase_clear(&ma->gpumaterial);

  ma->gp_style = newdataadr(fd, ma->gp_style);
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Read ID: Particle Settings
 * \{ */

/* update this also to writefile.c */
static const char *ptcache_data_struct[] = {
    "",          // BPHYS_DATA_INDEX
    "",          // BPHYS_DATA_LOCATION
    "",          // BPHYS_DATA_VELOCITY
    "",          // BPHYS_DATA_ROTATION
    "",          // BPHYS_DATA_AVELOCITY / BPHYS_DATA_XCONST */
    "",          // BPHYS_DATA_SIZE:
    "",          // BPHYS_DATA_TIMES:
    "BoidData",  // case BPHYS_DATA_BOIDS:
};

static void direct_link_pointcache_cb(FileData *fd, void *data)
{
  PTCacheMem *pm = data;
  PTCacheExtra *extra;
  int i;
  for (i = 0; i < BPHYS_TOT_DATA; i++) {
    pm->data[i] = newdataadr(fd, pm->data[i]);

    /* the cache saves non-struct data without DNA */
    if (pm->data[i] && ptcache_data_struct[i][0] == '\0' && (fd->flags & FD_FLAGS_SWITCH_ENDIAN)) {
      /* data_size returns bytes. */
      int tot = (BKE_ptcache_data_size(i) * pm->totpoint) / sizeof(int);

      int *poin = pm->data[i];

      BLI_endian_switch_int32_array(poin, tot);
    }
  }

  link_list(fd, &pm->extradata);

  for (extra = pm->extradata.first; extra; extra = extra->next) {
    extra->data = newdataadr(fd, extra->data);
  }
}

static void direct_link_pointcache(FileData *fd, PointCache *cache)
{
  if ((cache->flag & PTCACHE_DISK_CACHE) == 0) {
    link_list_ex(fd, &cache->mem_cache, direct_link_pointcache_cb);
  }
  else {
    BLI_listbase_clear(&cache->mem_cache);
  }

  cache->flag &= ~PTCACHE_SIMULATION_VALID;
  cache->simframe = 0;
  cache->edit = NULL;
  cache->free_edit = NULL;
  cache->cached_frames = NULL;
  cache->cached_frames_len = 0;
}

static void direct_link_pointcache_list(FileData *fd,
                                        ListBase *ptcaches,
                                        PointCache **ocache,
                                        int force_disk)
{
  if (ptcaches->first) {
    PointCache *cache = NULL;
    link_list(fd, ptcaches);
    for (cache = ptcaches->first; cache; cache = cache->next) {
      direct_link_pointcache(fd, cache);
      if (force_disk) {
        cache->flag |= PTCACHE_DISK_CACHE;
        cache->step = 1;
      }
    }

    *ocache = newdataadr(fd, *ocache);
  }
  else if (*ocache) {
    /* old "single" caches need to be linked too */
    *ocache = newdataadr(fd, *ocache);
    direct_link_pointcache(fd, *ocache);
    if (force_disk) {
      (*ocache)->flag |= PTCACHE_DISK_CACHE;
      (*ocache)->step = 1;
    }

    ptcaches->first = ptcaches->last = *ocache;
  }
}

static void lib_link_partdeflect(FileData *fd, ID *id, PartDeflect *pd)
{
  if (pd && pd->tex) {
    pd->tex = newlibadr_us(fd, id->lib, pd->tex);
  }
  if (pd && pd->f_source) {
    pd->f_source = newlibadr(fd, id->lib, pd->f_source);
  }
}

static void lib_link_particlesettings(FileData *fd, Main *main)
{
  for (ParticleSettings *part = main->particles.first; part; part = part->id.next) {
    if (part->id.tag & LIB_TAG_NEED_LINK) {
      IDP_LibLinkProperty(part->id.properties, fd);
      lib_link_animdata(fd, &part->id, part->adt);

      part->ipo = newlibadr_us(
          fd, part->id.lib, part->ipo);  // XXX deprecated - old animation system

      part->instance_object = newlibadr(fd, part->id.lib, part->instance_object);
      part->instance_collection = newlibadr_us(fd, part->id.lib, part->instance_collection);
      part->eff_group = newlibadr(fd, part->id.lib, part->eff_group);
      part->bb_ob = newlibadr(fd, part->id.lib, part->bb_ob);
      part->collision_group = newlibadr(fd, part->id.lib, part->collision_group);

      lib_link_partdeflect(fd, &part->id, part->pd);
      lib_link_partdeflect(fd, &part->id, part->pd2);

      if (part->effector_weights) {
        part->effector_weights->group = newlibadr(fd, part->id.lib, part->effector_weights->group);
      }
      else {
        part->effector_weights = BKE_effector_add_weights(part->eff_group);
      }

      if (part->instance_weights.first && part->instance_collection) {
        for (ParticleDupliWeight *dw = part->instance_weights.first; dw; dw = dw->next) {
          dw->ob = newlibadr(fd, part->id.lib, dw->ob);
        }
      }
      else {
        BLI_listbase_clear(&part->instance_weights);
      }

      if (part->boids) {
        BoidState *state = part->boids->states.first;
        BoidRule *rule;
        for (; state; state = state->next) {
          rule = state->rules.first;
          for (; rule; rule = rule->next) {
            switch (rule->type) {
              case eBoidRuleType_Goal:
              case eBoidRuleType_Avoid: {
                BoidRuleGoalAvoid *brga = (BoidRuleGoalAvoid *)rule;
                brga->ob = newlibadr(fd, part->id.lib, brga->ob);
                break;
              }
              case eBoidRuleType_FollowLeader: {
                BoidRuleFollowLeader *brfl = (BoidRuleFollowLeader *)rule;
                brfl->ob = newlibadr(fd, part->id.lib, brfl->ob);
                break;
              }
            }
          }
        }
      }

      for (int a = 0; a < MAX_MTEX; a++) {
        MTex *mtex = part->mtex[a];
        if (mtex) {
          mtex->tex = newlibadr_us(fd, part->id.lib, mtex->tex);
          mtex->object = newlibadr(fd, part->id.lib, mtex->object);
        }
      }

      part->id.tag &= ~LIB_TAG_NEED_LINK;
    }
  }
}

static void direct_link_partdeflect(PartDeflect *pd)
{
  if (pd) {
    pd->rng = NULL;
  }
}

static void direct_link_particlesettings(FileData *fd, ParticleSettings *part)
{
  int a;

  part->adt = newdataadr(fd, part->adt);
  part->pd = newdataadr(fd, part->pd);
  part->pd2 = newdataadr(fd, part->pd2);

  direct_link_animdata(fd, part->adt);
  direct_link_partdeflect(part->pd);
  direct_link_partdeflect(part->pd2);

  part->clumpcurve = newdataadr(fd, part->clumpcurve);
  if (part->clumpcurve) {
    direct_link_curvemapping(fd, part->clumpcurve);
  }
  part->roughcurve = newdataadr(fd, part->roughcurve);
  if (part->roughcurve) {
    direct_link_curvemapping(fd, part->roughcurve);
  }
  part->twistcurve = newdataadr(fd, part->twistcurve);
  if (part->twistcurve) {
    direct_link_curvemapping(fd, part->twistcurve);
  }

  part->effector_weights = newdataadr(fd, part->effector_weights);
  if (!part->effector_weights) {
    part->effector_weights = BKE_effector_add_weights(part->eff_group);
  }

  link_list(fd, &part->instance_weights);

  part->boids = newdataadr(fd, part->boids);
  part->fluid = newdataadr(fd, part->fluid);

  if (part->boids) {
    BoidState *state;
    link_list(fd, &part->boids->states);

    for (state = part->boids->states.first; state; state = state->next) {
      link_list(fd, &state->rules);
      link_list(fd, &state->conditions);
      link_list(fd, &state->actions);
    }
  }
  for (a = 0; a < MAX_MTEX; a++) {
    part->mtex[a] = newdataadr(fd, part->mtex[a]);
  }

  /* Protect against integer overflow vulnerability. */
  CLAMP(part->trail_count, 1, 100000);
}

static void lib_link_particlesystems(FileData *fd, Object *ob, ID *id, ListBase *particles)
{
  ParticleSystem *psys, *psysnext;

  for (psys = particles->first; psys; psys = psysnext) {
    psysnext = psys->next;

    psys->part = newlibadr_us(fd, id->lib, psys->part);
    if (psys->part) {
      ParticleTarget *pt = psys->targets.first;

      for (; pt; pt = pt->next) {
        pt->ob = newlibadr(fd, id->lib, pt->ob);
      }

      psys->parent = newlibadr(fd, id->lib, psys->parent);
      psys->target_ob = newlibadr(fd, id->lib, psys->target_ob);

      if (psys->clmd) {
        /* XXX - from reading existing code this seems correct but intended usage of
         * pointcache /w cloth should be added in 'ParticleSystem' - campbell */
        psys->clmd->point_cache = psys->pointcache;
        psys->clmd->ptcaches.first = psys->clmd->ptcaches.last = NULL;
        psys->clmd->coll_parms->group = newlibadr(fd, id->lib, psys->clmd->coll_parms->group);
        psys->clmd->modifier.error = NULL;
      }
    }
    else {
      /* particle modifier must be removed before particle system */
      ParticleSystemModifierData *psmd = psys_get_modifier(ob, psys);
      BLI_remlink(&ob->modifiers, psmd);
      modifier_free((ModifierData *)psmd);

      BLI_remlink(particles, psys);
      MEM_freeN(psys);
    }
  }
}
static void direct_link_particlesystems(FileData *fd, ListBase *particles)
{
  ParticleSystem *psys;
  ParticleData *pa;
  int a;

  for (psys = particles->first; psys; psys = psys->next) {
    psys->particles = newdataadr(fd, psys->particles);

    if (psys->particles && psys->particles->hair) {
      for (a = 0, pa = psys->particles; a < psys->totpart; a++, pa++) {
        pa->hair = newdataadr(fd, pa->hair);
      }
    }

    if (psys->particles && psys->particles->keys) {
      for (a = 0, pa = psys->particles; a < psys->totpart; a++, pa++) {
        pa->keys = NULL;
        pa->totkey = 0;
      }

      psys->flag &= ~PSYS_KEYED;
    }

    if (psys->particles && psys->particles->boid) {
      pa = psys->particles;
      pa->boid = newdataadr(fd, pa->boid);

      /* This is purely runtime data, but still can be an issue if left dangling. */
      pa->boid->ground = NULL;

      for (a = 1, pa++; a < psys->totpart; a++, pa++) {
        pa->boid = (pa - 1)->boid + 1;
        pa->boid->ground = NULL;
      }
    }
    else if (psys->particles) {
      for (a = 0, pa = psys->particles; a < psys->totpart; a++, pa++) {
        pa->boid = NULL;
      }
    }

    psys->fluid_springs = newdataadr(fd, psys->fluid_springs);

    psys->child = newdataadr(fd, psys->child);
    psys->effectors = NULL;

    link_list(fd, &psys->targets);

    psys->edit = NULL;
    psys->free_edit = NULL;
    psys->pathcache = NULL;
    psys->childcache = NULL;
    BLI_listbase_clear(&psys->pathcachebufs);
    BLI_listbase_clear(&psys->childcachebufs);
    psys->pdd = NULL;

    if (psys->clmd) {
      psys->clmd = newdataadr(fd, psys->clmd);
      psys->clmd->clothObject = NULL;
      psys->clmd->hairdata = NULL;

      psys->clmd->sim_parms = newdataadr(fd, psys->clmd->sim_parms);
      psys->clmd->coll_parms = newdataadr(fd, psys->clmd->coll_parms);

      if (psys->clmd->sim_parms) {
        psys->clmd->sim_parms->effector_weights = NULL;
        if (psys->clmd->sim_parms->presets > 10) {
          psys->clmd->sim_parms->presets = 0;
        }
      }

      psys->hair_in_mesh = psys->hair_out_mesh = NULL;
      psys->clmd->solver_result = NULL;
    }

    direct_link_pointcache_list(fd, &psys->ptcaches, &psys->pointcache, 0);
    if (psys->clmd) {
      psys->clmd->point_cache = psys->pointcache;
    }

    psys->tree = NULL;
    psys->bvhtree = NULL;

    psys->orig_psys = NULL;
    psys->batch_cache = NULL;
  }
  return;
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Read ID: Mesh
 * \{ */

static void lib_link_mesh(FileData *fd, Main *main)
{
  Mesh *me;

  for (me = main->meshes.first; me; me = me->id.next) {
    if (me->id.tag & LIB_TAG_NEED_LINK) {
      int i;

      /* Link ID Properties -- and copy this comment EXACTLY for easy finding
       * of library blocks that implement this.*/
      IDP_LibLinkProperty(me->id.properties, fd);
      lib_link_animdata(fd, &me->id, me->adt);

      /* this check added for python created meshes */
      if (me->mat) {
        for (i = 0; i < me->totcol; i++) {
          me->mat[i] = newlibadr_us(fd, me->id.lib, me->mat[i]);
        }
      }
      else {
        me->totcol = 0;
      }

      me->ipo = newlibadr_us(fd, me->id.lib, me->ipo);  // XXX: deprecated: old anim sys
      me->key = newlibadr_us(fd, me->id.lib, me->key);
      me->texcomesh = newlibadr_us(fd, me->id.lib, me->texcomesh);
    }
  }

  for (me = main->meshes.first; me; me = me->id.next) {
    if (me->id.tag & LIB_TAG_NEED_LINK) {
      /*check if we need to convert mfaces to mpolys*/
      if (me->totface && !me->totpoly) {
        /* temporarily switch main so that reading from
         * external CustomData works */
        Main *gmain = G_MAIN;
        G_MAIN = main;

        BKE_mesh_do_versions_convert_mfaces_to_mpolys(me);

        G_MAIN = gmain;
      }

      /*
       * Re-tessellate, even if the polys were just created from tessfaces, this
       * is important because it:
       * - fill the CD_ORIGINDEX layer
       * - gives consistency of tessface between loading from a file and
       *   converting an edited BMesh back into a mesh (i.e. it replaces
       *   quad tessfaces in a loaded mesh immediately, instead of lazily
       *   waiting until edit mode has been entered/exited, making it easier
       *   to recognize problems that would otherwise only show up after edits).
       */
#ifdef USE_TESSFACE_DEFAULT
      BKE_mesh_tessface_calc(me);
#else
      BKE_mesh_tessface_clear(me);
#endif

      me->id.tag &= ~LIB_TAG_NEED_LINK;
    }
  }
}

static void direct_link_dverts(FileData *fd, int count, MDeformVert *mdverts)
{
  int i;

  if (mdverts == NULL) {
    return;
  }

  for (i = count; i > 0; i--, mdverts++) {
    /*convert to vgroup allocation system*/
    MDeformWeight *dw;
    if (mdverts->dw && (dw = newdataadr(fd, mdverts->dw))) {
      const ssize_t dw_len = mdverts->totweight * sizeof(MDeformWeight);
      void *dw_tmp = MEM_mallocN(dw_len, "direct_link_dverts");
      memcpy(dw_tmp, dw, dw_len);
      mdverts->dw = dw_tmp;
      MEM_freeN(dw);
    }
    else {
      mdverts->dw = NULL;
      mdverts->totweight = 0;
    }
  }
}

static void direct_link_mdisps(FileData *fd, int count, MDisps *mdisps, int external)
{
  if (mdisps) {
    int i;

    for (i = 0; i < count; ++i) {
      mdisps[i].disps = newdataadr(fd, mdisps[i].disps);
      mdisps[i].hidden = newdataadr(fd, mdisps[i].hidden);

      if (mdisps[i].totdisp && !mdisps[i].level) {
        /* this calculation is only correct for loop mdisps;
         * if loading pre-BMesh face mdisps this will be
         * overwritten with the correct value in
         * bm_corners_to_loops() */
        float gridsize = sqrtf(mdisps[i].totdisp);
        mdisps[i].level = (int)(logf(gridsize - 1.0f) / (float)M_LN2) + 1;
      }

      if ((fd->flags & FD_FLAGS_SWITCH_ENDIAN) && (mdisps[i].disps)) {
        /* DNA_struct_switch_endian doesn't do endian swap for (*disps)[] */
        /* this does swap for data written at write_mdisps() - readfile.c */
        BLI_endian_switch_float_array(*mdisps[i].disps, mdisps[i].totdisp * 3);
      }
      if (!external && !mdisps[i].disps) {
        mdisps[i].totdisp = 0;
      }
    }
  }
}

static void direct_link_grid_paint_mask(FileData *fd, int count, GridPaintMask *grid_paint_mask)
{
  if (grid_paint_mask) {
    int i;

    for (i = 0; i < count; ++i) {
      GridPaintMask *gpm = &grid_paint_mask[i];
      if (gpm->data) {
        gpm->data = newdataadr(fd, gpm->data);
      }
    }
  }
}

/*this isn't really a public api function, so prototyped here*/
static void direct_link_customdata(FileData *fd, CustomData *data, int count)
{
  int i = 0;

  data->layers = newdataadr(fd, data->layers);

  /* annoying workaround for bug [#31079] loading legacy files with
   * no polygons _but_ have stale customdata */
  if (UNLIKELY(count == 0 && data->layers == NULL && data->totlayer != 0)) {
    CustomData_reset(data);
    return;
  }

  data->external = newdataadr(fd, data->external);

  while (i < data->totlayer) {
    CustomDataLayer *layer = &data->layers[i];

    if (layer->flag & CD_FLAG_EXTERNAL) {
      layer->flag &= ~CD_FLAG_IN_MEMORY;
    }

    layer->flag &= ~CD_FLAG_NOFREE;

    if (CustomData_verify_versions(data, i)) {
      layer->data = newdataadr(fd, layer->data);
      if (layer->type == CD_MDISPS) {
        direct_link_mdisps(fd, count, layer->data, layer->flag & CD_FLAG_EXTERNAL);
      }
      else if (layer->type == CD_GRID_PAINT_MASK) {
        direct_link_grid_paint_mask(fd, count, layer->data);
      }
      i++;
    }
  }

  CustomData_update_typemap(data);
}

static void direct_link_mesh(FileData *fd, Mesh *mesh)
{
  mesh->mat = newdataadr(fd, mesh->mat);
  test_pointer_array(fd, (void **)&mesh->mat);

  mesh->mvert = newdataadr(fd, mesh->mvert);
  mesh->medge = newdataadr(fd, mesh->medge);
  mesh->mface = newdataadr(fd, mesh->mface);
  mesh->mloop = newdataadr(fd, mesh->mloop);
  mesh->mpoly = newdataadr(fd, mesh->mpoly);
  mesh->tface = newdataadr(fd, mesh->tface);
  mesh->mtface = newdataadr(fd, mesh->mtface);
  mesh->mcol = newdataadr(fd, mesh->mcol);
  mesh->dvert = newdataadr(fd, mesh->dvert);
  mesh->mloopcol = newdataadr(fd, mesh->mloopcol);
  mesh->mloopuv = newdataadr(fd, mesh->mloopuv);
  mesh->mselect = newdataadr(fd, mesh->mselect);

  /* animdata */
  mesh->adt = newdataadr(fd, mesh->adt);
  direct_link_animdata(fd, mesh->adt);

  /* Normally direct_link_dverts should be called in direct_link_customdata,
   * but for backwards compatibility in do_versions to work we do it here. */
  direct_link_dverts(fd, mesh->totvert, mesh->dvert);

  direct_link_customdata(fd, &mesh->vdata, mesh->totvert);
  direct_link_customdata(fd, &mesh->edata, mesh->totedge);
  direct_link_customdata(fd, &mesh->fdata, mesh->totface);
  direct_link_customdata(fd, &mesh->ldata, mesh->totloop);
  direct_link_customdata(fd, &mesh->pdata, mesh->totpoly);

  mesh->bb = NULL;
  mesh->edit_mesh = NULL;
  BKE_mesh_runtime_reset(mesh);

  /* happens with old files */
  if (mesh->mselect == NULL) {
    mesh->totselect = 0;
  }

  /* Multires data */
  mesh->mr = newdataadr(fd, mesh->mr);
  if (mesh->mr) {
    MultiresLevel *lvl;

    link_list(fd, &mesh->mr->levels);
    lvl = mesh->mr->levels.first;

    direct_link_customdata(fd, &mesh->mr->vdata, lvl->totvert);
    direct_link_dverts(fd, lvl->totvert, CustomData_get(&mesh->mr->vdata, 0, CD_MDEFORMVERT));
    direct_link_customdata(fd, &mesh->mr->fdata, lvl->totface);

    mesh->mr->edge_flags = newdataadr(fd, mesh->mr->edge_flags);
    mesh->mr->edge_creases = newdataadr(fd, mesh->mr->edge_creases);

    mesh->mr->verts = newdataadr(fd, mesh->mr->verts);

    /* If mesh has the same number of vertices as the
     * highest multires level, load the current mesh verts
     * into multires and discard the old data. Needed
     * because some saved files either do not have a verts
     * array, or the verts array contains out-of-date
     * data. */
    if (mesh->totvert == ((MultiresLevel *)mesh->mr->levels.last)->totvert) {
      if (mesh->mr->verts) {
        MEM_freeN(mesh->mr->verts);
      }
      mesh->mr->verts = MEM_dupallocN(mesh->mvert);
    }

    for (; lvl; lvl = lvl->next) {
      lvl->verts = newdataadr(fd, lvl->verts);
      lvl->faces = newdataadr(fd, lvl->faces);
      lvl->edges = newdataadr(fd, lvl->edges);
      lvl->colfaces = newdataadr(fd, lvl->colfaces);
    }
  }

  /* if multires is present but has no valid vertex data,
   * there's no way to recover it; silently remove multires */
  if (mesh->mr && !mesh->mr->verts) {
    multires_free(mesh->mr);
    mesh->mr = NULL;
  }

  if ((fd->flags & FD_FLAGS_SWITCH_ENDIAN) && mesh->tface) {
    TFace *tf = mesh->tface;
    int i;

    for (i = 0; i < mesh->totface; i++, tf++) {
      BLI_endian_switch_uint32_array(tf->col, 4);
    }
  }
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Read ID: Lattice
 * \{ */

static void lib_link_latt(FileData *fd, Main *main)
{
  for (Lattice *lt = main->lattices.first; lt; lt = lt->id.next) {
    if (lt->id.tag & LIB_TAG_NEED_LINK) {
      IDP_LibLinkProperty(lt->id.properties, fd);
      lib_link_animdata(fd, &lt->id, lt->adt);

      lt->ipo = newlibadr_us(fd, lt->id.lib, lt->ipo);  // XXX deprecated - old animation system
      lt->key = newlibadr_us(fd, lt->id.lib, lt->key);

      lt->id.tag &= ~LIB_TAG_NEED_LINK;
    }
  }
}

static void direct_link_latt(FileData *fd, Lattice *lt)
{
  lt->def = newdataadr(fd, lt->def);

  lt->dvert = newdataadr(fd, lt->dvert);
  direct_link_dverts(fd, lt->pntsu * lt->pntsv * lt->pntsw, lt->dvert);

  lt->editlatt = NULL;
  lt->batch_cache = NULL;

  lt->adt = newdataadr(fd, lt->adt);
  direct_link_animdata(fd, lt->adt);
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Read ID: Object
 * \{ */

static void lib_link_modifiers_common(void *userData, Object *ob, ID **idpoin, int cb_flag)
{
  FileData *fd = userData;

  *idpoin = newlibadr(fd, ob->id.lib, *idpoin);
  if (*idpoin != NULL && (cb_flag & IDWALK_CB_USER) != 0) {
    id_us_plus_no_lib(*idpoin);
  }
}

static void lib_link_modifiers(FileData *fd, Object *ob)
{
  modifiers_foreachIDLink(ob, lib_link_modifiers_common, fd);

  /* If linking from a library, clear 'local' library override flag. */
  if (ob->id.lib != NULL) {
    for (ModifierData *mod = ob->modifiers.first; mod != NULL; mod = mod->next) {
      mod->flag &= ~eModifierFlag_OverrideLibrary_Local;
    }
  }
}

static void lib_link_gpencil_modifiers(FileData *fd, Object *ob)
{
  BKE_gpencil_modifiers_foreachIDLink(ob, lib_link_modifiers_common, fd);

  /* If linking from a library, clear 'local' library override flag. */
  if (ob->id.lib != NULL) {
    for (GpencilModifierData *mod = ob->greasepencil_modifiers.first; mod != NULL;
         mod = mod->next) {
      mod->flag &= ~eGpencilModifierFlag_OverrideLibrary_Local;
    }
  }
}

static void lib_link_shaderfxs(FileData *fd, Object *ob)
{
  BKE_shaderfx_foreachIDLink(ob, lib_link_modifiers_common, fd);

  /* If linking from a library, clear 'local' library override flag. */
  if (ob->id.lib != NULL) {
    for (ShaderFxData *fx = ob->shader_fx.first; fx != NULL; fx = fx->next) {
      fx->flag &= ~eShaderFxFlag_OverrideLibrary_Local;
    }
  }
}

static void lib_link_object(FileData *fd, Main *main)
{
  bool warn = false;

  for (Object *ob = main->objects.first; ob; ob = ob->id.next) {
    if (ob->id.tag & LIB_TAG_NEED_LINK) {
      int a;

      IDP_LibLinkProperty(ob->id.properties, fd);
      lib_link_animdata(fd, &ob->id, ob->adt);

      // XXX deprecated - old animation system <<<
      ob->ipo = newlibadr_us(fd, ob->id.lib, ob->ipo);
      ob->action = newlibadr_us(fd, ob->id.lib, ob->action);
      // >>> XXX deprecated - old animation system

      ob->parent = newlibadr(fd, ob->id.lib, ob->parent);
      ob->track = newlibadr(fd, ob->id.lib, ob->track);
      ob->poselib = newlibadr_us(fd, ob->id.lib, ob->poselib);

      /* 2.8x drops support for non-empty dupli instances. */
      if (ob->type == OB_EMPTY) {
        ob->instance_collection = newlibadr_us(fd, ob->id.lib, ob->instance_collection);
      }
      else {
        if (ob->instance_collection != NULL) {
          ID *id = newlibadr(fd, ob->id.lib, ob->instance_collection);
          blo_reportf_wrap(fd->reports,
                           RPT_WARNING,
                           TIP_("Non-Empty object '%s' cannot duplicate collection '%s' "
                                "anymore in Blender 2.80, removed instancing"),
                           ob->id.name + 2,
                           id->name + 2);
        }
        ob->instance_collection = NULL;
        ob->transflag &= ~OB_DUPLICOLLECTION;
      }

      ob->proxy = newlibadr_us(fd, ob->id.lib, ob->proxy);
      if (ob->proxy) {
        /* paranoia check, actually a proxy_from pointer should never be written... */
        if (ob->proxy->id.lib == NULL) {
          ob->proxy->proxy_from = NULL;
          ob->proxy = NULL;

          if (ob->id.lib) {
            printf("Proxy lost from  object %s lib %s\n", ob->id.name + 2, ob->id.lib->name);
          }
          else {
            printf("Proxy lost from  object %s lib <NONE>\n", ob->id.name + 2);
          }
        }
        else {
          /* this triggers object_update to always use a copy */
          ob->proxy->proxy_from = ob;
        }
      }
      ob->proxy_group = newlibadr(fd, ob->id.lib, ob->proxy_group);

      void *poin = ob->data;
      ob->data = newlibadr_us(fd, ob->id.lib, ob->data);

      if (ob->data == NULL && poin != NULL) {
        if (ob->id.lib) {
          printf("Can't find obdata of %s lib %s\n", ob->id.name + 2, ob->id.lib->name);
        }
        else {
          printf("Object %s lost data.\n", ob->id.name + 2);
        }

        ob->type = OB_EMPTY;
        warn = true;

        if (ob->pose) {
          /* we can't call #BKE_pose_free() here because of library linking
           * freeing will recurse down into every pose constraints ID pointers
           * which are not always valid, so for now free directly and suffer
           * some leaked memory rather then crashing immediately
           * while bad this _is_ an exceptional case - campbell */
#if 0
          BKE_pose_free(ob->pose);
#else
          MEM_freeN(ob->pose);
#endif
          ob->pose = NULL;
          ob->mode &= ~OB_MODE_POSE;
        }
      }
      for (a = 0; a < ob->totcol; a++) {
        ob->mat[a] = newlibadr_us(fd, ob->id.lib, ob->mat[a]);
      }

      /* When the object is local and the data is library its possible
       * the material list size gets out of sync. [#22663] */
      if (ob->data && ob->id.lib != ((ID *)ob->data)->lib) {
        const short *totcol_data = give_totcolp(ob);
        /* Only expand so as not to loose any object materials that might be set. */
        if (totcol_data && (*totcol_data > ob->totcol)) {
          /* printf("'%s' %d -> %d\n", ob->id.name, ob->totcol, *totcol_data); */
          BKE_material_resize_object(main, ob, *totcol_data, false);
        }
      }

      ob->gpd = newlibadr_us(fd, ob->id.lib, ob->gpd);

      ob->id.tag &= ~LIB_TAG_NEED_LINK;
      /* if id.us==0 a new base will be created later on */

      /* WARNING! Also check expand_object(), should reflect the stuff below. */
      lib_link_pose(fd, main, ob, ob->pose);
      lib_link_constraints(fd, &ob->id, &ob->constraints);

      // XXX deprecated - old animation system <<<
      lib_link_constraint_channels(fd, &ob->id, &ob->constraintChannels);
      lib_link_nlastrips(fd, &ob->id, &ob->nlastrips);
      // >>> XXX deprecated - old animation system

      for (PartEff *paf = ob->effect.first; paf; paf = paf->next) {
        if (paf->type == EFF_PARTICLE) {
          paf->group = newlibadr_us(fd, ob->id.lib, paf->group);
        }
      }

      {
        FluidsimModifierData *fluidmd = (FluidsimModifierData *)modifiers_findByType(
            ob, eModifierType_Fluidsim);

        if (fluidmd && fluidmd->fss) {
          fluidmd->fss->ipo = newlibadr_us(
              fd, ob->id.lib, fluidmd->fss->ipo);  // XXX deprecated - old animation system
        }
      }

      {
        SmokeModifierData *smd = (SmokeModifierData *)modifiers_findByType(ob,
                                                                           eModifierType_Smoke);

        if (smd && (smd->type == MOD_SMOKE_TYPE_DOMAIN) && smd->domain) {
          smd->domain->flags |=
              MOD_SMOKE_FILE_LOAD; /* flag for refreshing the simulation after loading */
        }
      }

      /* texture field */
      if (ob->pd) {
        lib_link_partdeflect(fd, &ob->id, ob->pd);
      }

      if (ob->soft) {
        ob->soft->collision_group = newlibadr(fd, ob->id.lib, ob->soft->collision_group);

        ob->soft->effector_weights->group = newlibadr(
            fd, ob->id.lib, ob->soft->effector_weights->group);
      }

      lib_link_particlesystems(fd, ob, &ob->id, &ob->particlesystem);
      lib_link_modifiers(fd, ob);
      lib_link_gpencil_modifiers(fd, ob);
      lib_link_shaderfxs(fd, ob);

      if (ob->rigidbody_constraint) {
        ob->rigidbody_constraint->ob1 = newlibadr(fd, ob->id.lib, ob->rigidbody_constraint->ob1);
        ob->rigidbody_constraint->ob2 = newlibadr(fd, ob->id.lib, ob->rigidbody_constraint->ob2);
      }

      {
        LodLevel *level;
        for (level = ob->lodlevels.first; level; level = level->next) {
          level->source = newlibadr(fd, ob->id.lib, level->source);

          if (!level->source && level == ob->lodlevels.first) {
            level->source = ob;
          }
        }
      }
    }
  }

  if (warn) {
    BKE_report(fd->reports, RPT_WARNING, "Warning in console");
  }
}

/* direct data for cache */
static void direct_link_motionpath(FileData *fd, bMotionPath *mpath)
{
  /* sanity check */
  if (mpath == NULL) {
    return;
  }

  /* relink points cache */
  mpath->points = newdataadr(fd, mpath->points);

  mpath->points_vbo = NULL;
  mpath->batch_line = NULL;
  mpath->batch_points = NULL;
}

static void direct_link_pose(FileData *fd, bPose *pose)
{
  bPoseChannel *pchan;

  if (!pose) {
    return;
  }

  link_list(fd, &pose->chanbase);
  link_list(fd, &pose->agroups);

  pose->chanhash = NULL;
  pose->chan_array = NULL;

  for (pchan = pose->chanbase.first; pchan; pchan = pchan->next) {
    pchan->bone = NULL;
    pchan->parent = newdataadr(fd, pchan->parent);
    pchan->child = newdataadr(fd, pchan->child);
    pchan->custom_tx = newdataadr(fd, pchan->custom_tx);

    pchan->bbone_prev = newdataadr(fd, pchan->bbone_prev);
    pchan->bbone_next = newdataadr(fd, pchan->bbone_next);

    direct_link_constraints(fd, &pchan->constraints);

    pchan->prop = newdataadr(fd, pchan->prop);
    IDP_DirectLinkGroup_OrFree(&pchan->prop, (fd->flags & FD_FLAGS_SWITCH_ENDIAN), fd);

    pchan->mpath = newdataadr(fd, pchan->mpath);
    if (pchan->mpath) {
      direct_link_motionpath(fd, pchan->mpath);
    }

    BLI_listbase_clear(&pchan->iktree);
    BLI_listbase_clear(&pchan->siktree);

    /* in case this value changes in future, clamp else we get undefined behavior */
    CLAMP(pchan->rotmode, ROT_MODE_MIN, ROT_MODE_MAX);

    pchan->draw_data = NULL;
    BKE_pose_channel_runtime_reset(&pchan->runtime);
  }
  pose->ikdata = NULL;
  if (pose->ikparam != NULL) {
    pose->ikparam = newdataadr(fd, pose->ikparam);
  }
}

static void direct_link_modifiers(FileData *fd, ListBase *lb)
{
  ModifierData *md;

  link_list(fd, lb);

  for (md = lb->first; md; md = md->next) {
    md->error = NULL;
    md->runtime = NULL;

    /* if modifiers disappear, or for upward compatibility */
    if (NULL == modifierType_getInfo(md->type)) {
      md->type = eModifierType_None;
    }

    if (md->type == eModifierType_Subsurf) {
      SubsurfModifierData *smd = (SubsurfModifierData *)md;

      smd->emCache = smd->mCache = NULL;
    }
    else if (md->type == eModifierType_Armature) {
      ArmatureModifierData *amd = (ArmatureModifierData *)md;

      amd->prevCos = NULL;
    }
    else if (md->type == eModifierType_Cloth) {
      ClothModifierData *clmd = (ClothModifierData *)md;

      clmd->clothObject = NULL;
      clmd->hairdata = NULL;

      clmd->sim_parms = newdataadr(fd, clmd->sim_parms);
      clmd->coll_parms = newdataadr(fd, clmd->coll_parms);

      direct_link_pointcache_list(fd, &clmd->ptcaches, &clmd->point_cache, 0);

      if (clmd->sim_parms) {
        if (clmd->sim_parms->presets > 10) {
          clmd->sim_parms->presets = 0;
        }

        clmd->sim_parms->reset = 0;

        clmd->sim_parms->effector_weights = newdataadr(fd, clmd->sim_parms->effector_weights);

        if (!clmd->sim_parms->effector_weights) {
          clmd->sim_parms->effector_weights = BKE_effector_add_weights(NULL);
        }
      }

      clmd->solver_result = NULL;
    }
    else if (md->type == eModifierType_Fluidsim) {
      FluidsimModifierData *fluidmd = (FluidsimModifierData *)md;

      fluidmd->fss = newdataadr(fd, fluidmd->fss);
      if (fluidmd->fss) {
        fluidmd->fss->fmd = fluidmd;
        fluidmd->fss->meshVelocities = NULL;
      }
    }
    else if (md->type == eModifierType_Smoke) {
      SmokeModifierData *smd = (SmokeModifierData *)md;

      if (smd->type == MOD_SMOKE_TYPE_DOMAIN) {
        smd->flow = NULL;
        smd->coll = NULL;
        smd->domain = newdataadr(fd, smd->domain);
        smd->domain->smd = smd;

        smd->domain->fluid = NULL;
        smd->domain->fluid_mutex = BLI_rw_mutex_alloc();
        smd->domain->wt = NULL;
        smd->domain->shadow = NULL;
        smd->domain->tex = NULL;
        smd->domain->tex_shadow = NULL;
        smd->domain->tex_flame = NULL;
        smd->domain->tex_flame_coba = NULL;
        smd->domain->tex_coba = NULL;
        smd->domain->tex_field = NULL;
        smd->domain->tex_velocity_x = NULL;
        smd->domain->tex_velocity_y = NULL;
        smd->domain->tex_velocity_z = NULL;
        smd->domain->tex_wt = NULL;
        smd->domain->coba = newdataadr(fd, smd->domain->coba);

        smd->domain->effector_weights = newdataadr(fd, smd->domain->effector_weights);
        if (!smd->domain->effector_weights) {
          smd->domain->effector_weights = BKE_effector_add_weights(NULL);
        }

        direct_link_pointcache_list(
            fd, &(smd->domain->ptcaches[0]), &(smd->domain->point_cache[0]), 1);

        /* Smoke uses only one cache from now on, so store pointer convert */
        if (smd->domain->ptcaches[1].first || smd->domain->point_cache[1]) {
          if (smd->domain->point_cache[1]) {
            PointCache *cache = newdataadr(fd, smd->domain->point_cache[1]);
            if (cache->flag & PTCACHE_FAKE_SMOKE) {
              /* Smoke was already saved in "new format" and this cache is a fake one. */
            }
            else {
              printf(
                  "High resolution smoke cache not available due to pointcache update. Please "
                  "reset the simulation.\n");
            }
            BKE_ptcache_free(cache);
          }
          BLI_listbase_clear(&smd->domain->ptcaches[1]);
          smd->domain->point_cache[1] = NULL;
        }
      }
      else if (smd->type == MOD_SMOKE_TYPE_FLOW) {
        smd->domain = NULL;
        smd->coll = NULL;
        smd->flow = newdataadr(fd, smd->flow);
        smd->flow->smd = smd;
        smd->flow->mesh = NULL;
        smd->flow->verts_old = NULL;
        smd->flow->numverts = 0;
        smd->flow->psys = newdataadr(fd, smd->flow->psys);
      }
      else if (smd->type == MOD_SMOKE_TYPE_COLL) {
        smd->flow = NULL;
        smd->domain = NULL;
        smd->coll = newdataadr(fd, smd->coll);
        if (smd->coll) {
          smd->coll->smd = smd;
          smd->coll->verts_old = NULL;
          smd->coll->numverts = 0;
          smd->coll->mesh = NULL;
        }
        else {
          smd->type = 0;
          smd->flow = NULL;
          smd->domain = NULL;
          smd->coll = NULL;
        }
      }
    }
    else if (md->type == eModifierType_DynamicPaint) {
      DynamicPaintModifierData *pmd = (DynamicPaintModifierData *)md;

      if (pmd->canvas) {
        pmd->canvas = newdataadr(fd, pmd->canvas);
        pmd->canvas->pmd = pmd;
        pmd->canvas->flags &= ~MOD_DPAINT_BAKING; /* just in case */

        if (pmd->canvas->surfaces.first) {
          DynamicPaintSurface *surface;
          link_list(fd, &pmd->canvas->surfaces);

          for (surface = pmd->canvas->surfaces.first; surface; surface = surface->next) {
            surface->canvas = pmd->canvas;
            surface->data = NULL;
            direct_link_pointcache_list(fd, &(surface->ptcaches), &(surface->pointcache), 1);

            if (!(surface->effector_weights = newdataadr(fd, surface->effector_weights))) {
              surface->effector_weights = BKE_effector_add_weights(NULL);
            }
          }
        }
      }
      if (pmd->brush) {
        pmd->brush = newdataadr(fd, pmd->brush);
        pmd->brush->pmd = pmd;
        pmd->brush->psys = newdataadr(fd, pmd->brush->psys);
        pmd->brush->paint_ramp = newdataadr(fd, pmd->brush->paint_ramp);
        pmd->brush->vel_ramp = newdataadr(fd, pmd->brush->vel_ramp);
      }
    }
    else if (md->type == eModifierType_Collision) {
      CollisionModifierData *collmd = (CollisionModifierData *)md;
#if 0
      // TODO: CollisionModifier should use pointcache
      // + have proper reset events before enabling this
      collmd->x = newdataadr(fd, collmd->x);
      collmd->xnew = newdataadr(fd, collmd->xnew);
      collmd->mfaces = newdataadr(fd, collmd->mfaces);

      collmd->current_x = MEM_calloc_arrayN(collmd->numverts, sizeof(MVert), "current_x");
      collmd->current_xnew = MEM_calloc_arrayN(collmd->numverts, sizeof(MVert), "current_xnew");
      collmd->current_v = MEM_calloc_arrayN(collmd->numverts, sizeof(MVert), "current_v");
#endif

      collmd->x = NULL;
      collmd->xnew = NULL;
      collmd->current_x = NULL;
      collmd->current_xnew = NULL;
      collmd->current_v = NULL;
      collmd->time_x = collmd->time_xnew = -1000;
      collmd->mvert_num = 0;
      collmd->tri_num = 0;
      collmd->is_static = false;
      collmd->bvhtree = NULL;
      collmd->tri = NULL;
    }
    else if (md->type == eModifierType_Surface) {
      SurfaceModifierData *surmd = (SurfaceModifierData *)md;

      surmd->mesh = NULL;
      surmd->bvhtree = NULL;
      surmd->x = NULL;
      surmd->v = NULL;
      surmd->numverts = 0;
    }
    else if (md->type == eModifierType_Hook) {
      HookModifierData *hmd = (HookModifierData *)md;

      hmd->indexar = newdataadr(fd, hmd->indexar);
      if (fd->flags & FD_FLAGS_SWITCH_ENDIAN) {
        BLI_endian_switch_int32_array(hmd->indexar, hmd->totindex);
      }

      hmd->curfalloff = newdataadr(fd, hmd->curfalloff);
      if (hmd->curfalloff) {
        direct_link_curvemapping(fd, hmd->curfalloff);
      }
    }
    else if (md->type == eModifierType_ParticleSystem) {
      ParticleSystemModifierData *psmd = (ParticleSystemModifierData *)md;

      psmd->mesh_final = NULL;
      psmd->mesh_original = NULL;
      psmd->psys = newdataadr(fd, psmd->psys);
      psmd->flag &= ~eParticleSystemFlag_psys_updated;
      psmd->flag |= eParticleSystemFlag_file_loaded;
    }
    else if (md->type == eModifierType_Explode) {
      ExplodeModifierData *psmd = (ExplodeModifierData *)md;

      psmd->facepa = NULL;
    }
    else if (md->type == eModifierType_MeshDeform) {
      MeshDeformModifierData *mmd = (MeshDeformModifierData *)md;

      mmd->bindinfluences = newdataadr(fd, mmd->bindinfluences);
      mmd->bindoffsets = newdataadr(fd, mmd->bindoffsets);
      mmd->bindcagecos = newdataadr(fd, mmd->bindcagecos);
      mmd->dyngrid = newdataadr(fd, mmd->dyngrid);
      mmd->dyninfluences = newdataadr(fd, mmd->dyninfluences);
      mmd->dynverts = newdataadr(fd, mmd->dynverts);

      mmd->bindweights = newdataadr(fd, mmd->bindweights);
      mmd->bindcos = newdataadr(fd, mmd->bindcos);

      if (fd->flags & FD_FLAGS_SWITCH_ENDIAN) {
        if (mmd->bindoffsets) {
          BLI_endian_switch_int32_array(mmd->bindoffsets, mmd->totvert + 1);
        }
        if (mmd->bindcagecos) {
          BLI_endian_switch_float_array(mmd->bindcagecos, mmd->totcagevert * 3);
        }
        if (mmd->dynverts) {
          BLI_endian_switch_int32_array(mmd->dynverts, mmd->totvert);
        }
        if (mmd->bindweights) {
          BLI_endian_switch_float_array(mmd->bindweights, mmd->totvert);
        }
        if (mmd->bindcos) {
          BLI_endian_switch_float_array(mmd->bindcos, mmd->totcagevert * 3);
        }
      }
    }
    else if (md->type == eModifierType_Ocean) {
      OceanModifierData *omd = (OceanModifierData *)md;
      omd->oceancache = NULL;
      omd->ocean = NULL;
    }
    else if (md->type == eModifierType_Warp) {
      WarpModifierData *tmd = (WarpModifierData *)md;

      tmd->curfalloff = newdataadr(fd, tmd->curfalloff);
      if (tmd->curfalloff) {
        direct_link_curvemapping(fd, tmd->curfalloff);
      }
    }
    else if (md->type == eModifierType_WeightVGEdit) {
      WeightVGEditModifierData *wmd = (WeightVGEditModifierData *)md;

      wmd->cmap_curve = newdataadr(fd, wmd->cmap_curve);
      if (wmd->cmap_curve) {
        direct_link_curvemapping(fd, wmd->cmap_curve);
      }
    }
    else if (md->type == eModifierType_LaplacianDeform) {
      LaplacianDeformModifierData *lmd = (LaplacianDeformModifierData *)md;

      lmd->vertexco = newdataadr(fd, lmd->vertexco);
      if (fd->flags & FD_FLAGS_SWITCH_ENDIAN) {
        BLI_endian_switch_float_array(lmd->vertexco, lmd->total_verts * 3);
      }
      lmd->cache_system = NULL;
    }
    else if (md->type == eModifierType_CorrectiveSmooth) {
      CorrectiveSmoothModifierData *csmd = (CorrectiveSmoothModifierData *)md;

      if (csmd->bind_coords) {
        csmd->bind_coords = newdataadr(fd, csmd->bind_coords);
        if (fd->flags & FD_FLAGS_SWITCH_ENDIAN) {
          BLI_endian_switch_float_array((float *)csmd->bind_coords, csmd->bind_coords_num * 3);
        }
      }

      /* runtime only */
      csmd->delta_cache = NULL;
      csmd->delta_cache_num = 0;
    }
    else if (md->type == eModifierType_MeshSequenceCache) {
      MeshSeqCacheModifierData *msmcd = (MeshSeqCacheModifierData *)md;
      msmcd->reader = NULL;
      msmcd->reader_object_path[0] = '\0';
    }
    else if (md->type == eModifierType_SurfaceDeform) {
      SurfaceDeformModifierData *smd = (SurfaceDeformModifierData *)md;

      smd->verts = newdataadr(fd, smd->verts);

      if (smd->verts) {
        for (int i = 0; i < smd->numverts; i++) {
          smd->verts[i].binds = newdataadr(fd, smd->verts[i].binds);

          if (smd->verts[i].binds) {
            for (int j = 0; j < smd->verts[i].numbinds; j++) {
              smd->verts[i].binds[j].vert_inds = newdataadr(fd, smd->verts[i].binds[j].vert_inds);
              smd->verts[i].binds[j].vert_weights = newdataadr(
                  fd, smd->verts[i].binds[j].vert_weights);

              if (fd->flags & FD_FLAGS_SWITCH_ENDIAN) {
                if (smd->verts[i].binds[j].vert_inds) {
                  BLI_endian_switch_uint32_array(smd->verts[i].binds[j].vert_inds,
                                                 smd->verts[i].binds[j].numverts);
                }

                if (smd->verts[i].binds[j].vert_weights) {
                  if (smd->verts[i].binds[j].mode == MOD_SDEF_MODE_CENTROID ||
                      smd->verts[i].binds[j].mode == MOD_SDEF_MODE_LOOPTRI) {
                    BLI_endian_switch_float_array(smd->verts[i].binds[j].vert_weights, 3);
                  }
                  else {
                    BLI_endian_switch_float_array(smd->verts[i].binds[j].vert_weights,
                                                  smd->verts[i].binds[j].numverts);
                  }
                }
              }
            }
          }
        }
      }
    }
  }
}

static void direct_link_gpencil_modifiers(FileData *fd, ListBase *lb)
{
  GpencilModifierData *md;

  link_list(fd, lb);

  for (md = lb->first; md; md = md->next) {
    md->error = NULL;

    /* if modifiers disappear, or for upward compatibility */
    if (NULL == BKE_gpencil_modifierType_getInfo(md->type)) {
      md->type = eModifierType_None;
    }

    if (md->type == eGpencilModifierType_Lattice) {
      LatticeGpencilModifierData *gpmd = (LatticeGpencilModifierData *)md;
      gpmd->cache_data = NULL;
    }
    else if (md->type == eGpencilModifierType_Hook) {
      HookGpencilModifierData *hmd = (HookGpencilModifierData *)md;

      hmd->curfalloff = newdataadr(fd, hmd->curfalloff);
      if (hmd->curfalloff) {
        direct_link_curvemapping(fd, hmd->curfalloff);
      }
    }
    else if (md->type == eGpencilModifierType_Thick) {
      ThickGpencilModifierData *gpmd = (ThickGpencilModifierData *)md;

      gpmd->curve_thickness = newdataadr(fd, gpmd->curve_thickness);
      if (gpmd->curve_thickness) {
        direct_link_curvemapping(fd, gpmd->curve_thickness);
        /* initialize the curve. Maybe this could be moved to modififer logic */
        BKE_curvemapping_initialize(gpmd->curve_thickness);
      }
    }
  }
}

static void direct_link_shaderfxs(FileData *fd, ListBase *lb)
{
  ShaderFxData *fx;

  link_list(fd, lb);

  for (fx = lb->first; fx; fx = fx->next) {
    fx->error = NULL;

    /* if shader disappear, or for upward compatibility */
    if (NULL == BKE_shaderfxType_getInfo(fx->type)) {
      fx->type = eShaderFxType_None;
    }
  }
}

static void direct_link_object(FileData *fd, Object *ob)
{
  PartEff *paf;

  /* XXX This should not be needed - but seems like it can happen in some cases,
   * so for now play safe. */
  ob->proxy_from = NULL;

  /* loading saved files with editmode enabled works, but for undo we like
   * to stay in object mode during undo presses so keep editmode disabled.
   *
   * Also when linking in a file don't allow edit and pose modes.
   * See [#34776, #42780] for more information.
   */
  if (fd->memfile || (ob->id.tag & (LIB_TAG_EXTERN | LIB_TAG_INDIRECT))) {
    ob->mode &= ~(OB_MODE_EDIT | OB_MODE_PARTICLE_EDIT);
    if (!fd->memfile) {
      ob->mode &= ~OB_MODE_POSE;
    }
  }

  ob->adt = newdataadr(fd, ob->adt);
  direct_link_animdata(fd, ob->adt);

  ob->pose = newdataadr(fd, ob->pose);
  direct_link_pose(fd, ob->pose);

  ob->mpath = newdataadr(fd, ob->mpath);
  if (ob->mpath) {
    direct_link_motionpath(fd, ob->mpath);
  }

  link_list(fd, &ob->defbase);
  link_list(fd, &ob->fmaps);
  // XXX deprecated - old animation system <<<
  direct_link_nlastrips(fd, &ob->nlastrips);
  link_list(fd, &ob->constraintChannels);
  // >>> XXX deprecated - old animation system

  ob->mat = newdataadr(fd, ob->mat);
  test_pointer_array(fd, (void **)&ob->mat);
  ob->matbits = newdataadr(fd, ob->matbits);

  /* do it here, below old data gets converted */
  direct_link_modifiers(fd, &ob->modifiers);
  direct_link_gpencil_modifiers(fd, &ob->greasepencil_modifiers);
  direct_link_shaderfxs(fd, &ob->shader_fx);

  link_list(fd, &ob->effect);
  paf = ob->effect.first;
  while (paf) {
    if (paf->type == EFF_PARTICLE) {
      paf->keys = NULL;
    }
    if (paf->type == EFF_WAVE) {
      WaveEff *wav = (WaveEff *)paf;
      PartEff *next = paf->next;
      WaveModifierData *wmd = (WaveModifierData *)modifier_new(eModifierType_Wave);

      wmd->damp = wav->damp;
      wmd->flag = wav->flag;
      wmd->height = wav->height;
      wmd->lifetime = wav->lifetime;
      wmd->narrow = wav->narrow;
      wmd->speed = wav->speed;
      wmd->startx = wav->startx;
      wmd->starty = wav->startx;
      wmd->timeoffs = wav->timeoffs;
      wmd->width = wav->width;

      BLI_addtail(&ob->modifiers, wmd);

      BLI_remlink(&ob->effect, paf);
      MEM_freeN(paf);

      paf = next;
      continue;
    }
    if (paf->type == EFF_BUILD) {
      BuildEff *baf = (BuildEff *)paf;
      PartEff *next = paf->next;
      BuildModifierData *bmd = (BuildModifierData *)modifier_new(eModifierType_Build);

      bmd->start = baf->sfra;
      bmd->length = baf->len;
      bmd->randomize = 0;
      bmd->seed = 1;

      BLI_addtail(&ob->modifiers, bmd);

      BLI_remlink(&ob->effect, paf);
      MEM_freeN(paf);

      paf = next;
      continue;
    }
    paf = paf->next;
  }

  ob->pd = newdataadr(fd, ob->pd);
  direct_link_partdeflect(ob->pd);
  ob->soft = newdataadr(fd, ob->soft);
  if (ob->soft) {
    SoftBody *sb = ob->soft;

    sb->bpoint = NULL;  // init pointers so it gets rebuilt nicely
    sb->bspring = NULL;
    sb->scratch = NULL;
    /* although not used anymore */
    /* still have to be loaded to be compatible with old files */
    sb->keys = newdataadr(fd, sb->keys);
    test_pointer_array(fd, (void **)&sb->keys);
    if (sb->keys) {
      int a;
      for (a = 0; a < sb->totkey; a++) {
        sb->keys[a] = newdataadr(fd, sb->keys[a]);
      }
    }

    sb->effector_weights = newdataadr(fd, sb->effector_weights);
    if (!sb->effector_weights) {
      sb->effector_weights = BKE_effector_add_weights(NULL);
    }

    sb->shared = newdataadr(fd, sb->shared);
    if (sb->shared == NULL) {
      /* Link deprecated caches if they exist, so we can use them for versioning.
       * We should only do this when sb->shared == NULL, because those pointers
       * are always set (for compatibility with older Blenders). We mustn't link
       * the same pointcache twice. */
      direct_link_pointcache_list(fd, &sb->ptcaches, &sb->pointcache, false);
    }
    else {
      /* link caches */
      direct_link_pointcache_list(fd, &sb->shared->ptcaches, &sb->shared->pointcache, false);
    }
  }
  ob->fluidsimSettings = newdataadr(fd, ob->fluidsimSettings); /* NT */

  ob->rigidbody_object = newdataadr(fd, ob->rigidbody_object);
  if (ob->rigidbody_object) {
    RigidBodyOb *rbo = ob->rigidbody_object;
    /* Allocate runtime-only struct */
    rbo->shared = MEM_callocN(sizeof(*rbo->shared), "RigidBodyObShared");
  }
  ob->rigidbody_constraint = newdataadr(fd, ob->rigidbody_constraint);
  if (ob->rigidbody_constraint) {
    ob->rigidbody_constraint->physics_constraint = NULL;
  }

  link_list(fd, &ob->particlesystem);
  direct_link_particlesystems(fd, &ob->particlesystem);

  direct_link_constraints(fd, &ob->constraints);

  link_list(fd, &ob->hooks);
  while (ob->hooks.first) {
    ObHook *hook = ob->hooks.first;
    HookModifierData *hmd = (HookModifierData *)modifier_new(eModifierType_Hook);

    hook->indexar = newdataadr(fd, hook->indexar);
    if (fd->flags & FD_FLAGS_SWITCH_ENDIAN) {
      BLI_endian_switch_int32_array(hook->indexar, hook->totindex);
    }

    /* Do conversion here because if we have loaded
     * a hook we need to make sure it gets converted
     * and freed, regardless of version.
     */
    copy_v3_v3(hmd->cent, hook->cent);
    hmd->falloff = hook->falloff;
    hmd->force = hook->force;
    hmd->indexar = hook->indexar;
    hmd->object = hook->parent;
    memcpy(hmd->parentinv, hook->parentinv, sizeof(hmd->parentinv));
    hmd->totindex = hook->totindex;

    BLI_addhead(&ob->modifiers, hmd);
    BLI_remlink(&ob->hooks, hook);

    modifier_unique_name(&ob->modifiers, (ModifierData *)hmd);

    MEM_freeN(hook);
  }

  ob->iuser = newdataadr(fd, ob->iuser);
  if (ob->type == OB_EMPTY && ob->empty_drawtype == OB_EMPTY_IMAGE && !ob->iuser) {
    BKE_object_empty_draw_type_set(ob, ob->empty_drawtype);
  }

  ob->derivedDeform = NULL;
  ob->derivedFinal = NULL;
  BKE_object_runtime_reset(ob);
  link_list(fd, &ob->pc_ids);

  /* in case this value changes in future, clamp else we get undefined behavior */
  CLAMP(ob->rotmode, ROT_MODE_MIN, ROT_MODE_MAX);

  if (ob->sculpt) {
    ob->sculpt = NULL;
    /* Only create data on undo, otherwise rely on editor mode switching. */
    if (fd->memfile && (ob->mode & OB_MODE_ALL_SCULPT)) {
      BKE_object_sculpt_data_create(ob);
    }
  }

  link_list(fd, &ob->lodlevels);
  ob->currentlod = ob->lodlevels.first;

  ob->preview = direct_link_preview_image(fd, ob->preview);
}

static void direct_link_view_settings(FileData *fd, ColorManagedViewSettings *view_settings)
{
  view_settings->curve_mapping = newdataadr(fd, view_settings->curve_mapping);

  if (view_settings->curve_mapping) {
    direct_link_curvemapping(fd, view_settings->curve_mapping);
  }
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Read View Layer (Collection Data)
 * \{ */

static void direct_link_layer_collections(FileData *fd, ListBase *lb, bool master)
{
  link_list(fd, lb);
  for (LayerCollection *lc = lb->first; lc; lc = lc->next) {
#ifdef USE_COLLECTION_COMPAT_28
    lc->scene_collection = newdataadr(fd, lc->scene_collection);
#endif

    /* Master collection is not a real data-lock. */
    if (master) {
      lc->collection = newdataadr(fd, lc->collection);
    }

    direct_link_layer_collections(fd, &lc->layer_collections, false);
  }
}

static void direct_link_view_layer(FileData *fd, ViewLayer *view_layer)
{
  view_layer->stats = NULL;
  link_list(fd, &view_layer->object_bases);
  view_layer->basact = newdataadr(fd, view_layer->basact);

  direct_link_layer_collections(fd, &view_layer->layer_collections, true);
  view_layer->active_collection = newdataadr(fd, view_layer->active_collection);

  view_layer->id_properties = newdataadr(fd, view_layer->id_properties);
  IDP_DirectLinkGroup_OrFree(&view_layer->id_properties, (fd->flags & FD_FLAGS_SWITCH_ENDIAN), fd);

  link_list(fd, &(view_layer->freestyle_config.modules));
  link_list(fd, &(view_layer->freestyle_config.linesets));

  BLI_listbase_clear(&view_layer->drawdata);
  view_layer->object_bases_array = NULL;
  view_layer->object_bases_hash = NULL;
}

static void lib_link_layer_collection(FileData *fd,
                                      Library *lib,
                                      LayerCollection *layer_collection,
                                      bool master)
{
  /* Master collection is not a real data-lock. */
  if (!master) {
    layer_collection->collection = newlibadr(fd, lib, layer_collection->collection);
  }

  for (LayerCollection *layer_collection_nested = layer_collection->layer_collections.first;
       layer_collection_nested != NULL;
       layer_collection_nested = layer_collection_nested->next) {
    lib_link_layer_collection(fd, lib, layer_collection_nested, false);
  }
}

static void lib_link_view_layer(FileData *fd, Library *lib, ViewLayer *view_layer)
{
  for (FreestyleModuleConfig *fmc = view_layer->freestyle_config.modules.first; fmc;
       fmc = fmc->next) {
    fmc->script = newlibadr(fd, lib, fmc->script);
  }

  for (FreestyleLineSet *fls = view_layer->freestyle_config.linesets.first; fls; fls = fls->next) {
    fls->linestyle = newlibadr_us(fd, lib, fls->linestyle);
    fls->group = newlibadr_us(fd, lib, fls->group);
  }

  for (Base *base = view_layer->object_bases.first, *base_next = NULL; base; base = base_next) {
    base_next = base->next;

    /* we only bump the use count for the collection objects */
    base->object = newlibadr(fd, lib, base->object);

    if (base->object == NULL) {
      /* Free in case linked object got lost. */
      BLI_freelinkN(&view_layer->object_bases, base);
      if (view_layer->basact == base) {
        view_layer->basact = NULL;
      }
    }
  }

  for (LayerCollection *layer_collection = view_layer->layer_collections.first;
       layer_collection != NULL;
       layer_collection = layer_collection->next) {
    lib_link_layer_collection(fd, lib, layer_collection, true);
  }

  view_layer->mat_override = newlibadr_us(fd, lib, view_layer->mat_override);

  IDP_LibLinkProperty(view_layer->id_properties, fd);
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Read ID: Collection
 * \{ */

#ifdef USE_COLLECTION_COMPAT_28
static void direct_link_scene_collection(FileData *fd, SceneCollection *sc)
{
  link_list(fd, &sc->objects);
  link_list(fd, &sc->scene_collections);

  for (SceneCollection *nsc = sc->scene_collections.first; nsc; nsc = nsc->next) {
    direct_link_scene_collection(fd, nsc);
  }
}

static void lib_link_scene_collection(FileData *fd, Library *lib, SceneCollection *sc)
{
  for (LinkData *link = sc->objects.first; link; link = link->next) {
    link->data = newlibadr_us(fd, lib, link->data);
    BLI_assert(link->data);
  }

  for (SceneCollection *nsc = sc->scene_collections.first; nsc; nsc = nsc->next) {
    lib_link_scene_collection(fd, lib, nsc);
  }
}
#endif

static void direct_link_collection(FileData *fd, Collection *collection)
{
  link_list(fd, &collection->gobject);
  link_list(fd, &collection->children);

  collection->preview = direct_link_preview_image(fd, collection->preview);

  collection->flag &= ~COLLECTION_HAS_OBJECT_CACHE;
  collection->tag = 0;
  BLI_listbase_clear(&collection->object_cache);
  BLI_listbase_clear(&collection->parents);

#ifdef USE_COLLECTION_COMPAT_28
  /* This runs before the very first doversion. */
  collection->collection = newdataadr(fd, collection->collection);
  if (collection->collection != NULL) {
    direct_link_scene_collection(fd, collection->collection);
  }

  collection->view_layer = newdataadr(fd, collection->view_layer);
  if (collection->view_layer != NULL) {
    direct_link_view_layer(fd, collection->view_layer);
  }
#endif
}

static void lib_link_collection_data(FileData *fd, Library *lib, Collection *collection)
{
  for (CollectionObject *cob = collection->gobject.first, *cob_next = NULL; cob; cob = cob_next) {
    cob_next = cob->next;
    cob->ob = newlibadr_us(fd, lib, cob->ob);

    if (cob->ob == NULL) {
      BLI_freelinkN(&collection->gobject, cob);
    }
  }

  for (CollectionChild *child = collection->children.first; child != NULL; child = child->next) {
    child->collection = newlibadr_us(fd, lib, child->collection);
  }

  BKE_collection_parent_relations_rebuild(collection);
}

static void lib_link_collection(FileData *fd, Main *main)
{
  for (Collection *collection = main->collections.first; collection;
       collection = collection->id.next) {
    if (collection->id.tag & LIB_TAG_NEED_LINK) {
      collection->id.tag &= ~LIB_TAG_NEED_LINK;
      IDP_LibLinkProperty(collection->id.properties, fd);

#ifdef USE_COLLECTION_COMPAT_28
      if (collection->collection) {
        lib_link_scene_collection(fd, collection->id.lib, collection->collection);
      }

      if (collection->view_layer) {
        lib_link_view_layer(fd, collection->id.lib, collection->view_layer);
      }
#endif

      lib_link_collection_data(fd, collection->id.lib, collection);
    }
  }
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Read ID: Scene
 * \{ */

/* patch for missing scene IDs, can't be in do-versions */
static void composite_patch(bNodeTree *ntree, Scene *scene)
{
  bNode *node;

  for (node = ntree->nodes.first; node; node = node->next) {
    if (node->id == NULL && node->type == CMP_NODE_R_LAYERS) {
      node->id = &scene->id;
    }
  }
}

static void link_paint(FileData *fd, Scene *sce, Paint *p)
{
  if (p) {
    p->brush = newlibadr_us(fd, sce->id.lib, p->brush);
    for (int i = 0; i < p->tool_slots_len; i++) {
      if (p->tool_slots[i].brush != NULL) {
        p->tool_slots[i].brush = newlibadr_us(fd, sce->id.lib, p->tool_slots[i].brush);
      }
    }
    p->palette = newlibadr_us(fd, sce->id.lib, p->palette);
    p->paint_cursor = NULL;

    BKE_paint_runtime_init(sce->toolsettings, p);
  }
}

static void lib_link_sequence_modifiers(FileData *fd, Scene *scene, ListBase *lb)
{
  SequenceModifierData *smd;

  for (smd = lb->first; smd; smd = smd->next) {
    if (smd->mask_id) {
      smd->mask_id = newlibadr_us(fd, scene->id.lib, smd->mask_id);
    }
  }
}

static void direct_link_lightcache_texture(FileData *fd, LightCacheTexture *lctex)
{
  lctex->tex = NULL;

  if (lctex->data) {
    lctex->data = newdataadr(fd, lctex->data);
    if (fd->flags & FD_FLAGS_SWITCH_ENDIAN) {
      int data_size = lctex->components * lctex->tex_size[0] * lctex->tex_size[1] *
                      lctex->tex_size[2];

      if (lctex->data_type == LIGHTCACHETEX_FLOAT) {
        BLI_endian_switch_float_array((float *)lctex->data, data_size * sizeof(float));
      }
      else if (lctex->data_type == LIGHTCACHETEX_UINT) {
        BLI_endian_switch_uint32_array((uint *)lctex->data, data_size * sizeof(uint));
      }
    }
  }
}

static void direct_link_lightcache(FileData *fd, LightCache *cache)
{
  direct_link_lightcache_texture(fd, &cache->cube_tx);
  direct_link_lightcache_texture(fd, &cache->grid_tx);

  if (cache->cube_mips) {
    cache->cube_mips = newdataadr(fd, cache->cube_mips);
    for (int i = 0; i < cache->mips_len; ++i) {
      direct_link_lightcache_texture(fd, &cache->cube_mips[i]);
    }
  }

  cache->cube_data = newdataadr(fd, cache->cube_data);
  cache->grid_data = newdataadr(fd, cache->grid_data);
}

/* check for cyclic set-scene,
 * libs can cause this case which is normally prevented, see (T#####) */
#define USE_SETSCENE_CHECK

#ifdef USE_SETSCENE_CHECK
/**
 * A version of #BKE_scene_validate_setscene with special checks for linked libs.
 */
static bool scene_validate_setscene__liblink(Scene *sce, const int totscene)
{
  Scene *sce_iter;
  int a;

  if (sce->set == NULL) {
    return 1;
  }

  for (a = 0, sce_iter = sce; sce_iter->set; sce_iter = sce_iter->set, a++) {
    if (sce_iter->id.tag & LIB_TAG_NEED_LINK) {
      return 1;
    }

    if (a > totscene) {
      sce->set = NULL;
      return 0;
    }
  }

  return 1;
}
#endif

static void lib_link_scene(FileData *fd, Main *main)
{
#ifdef USE_SETSCENE_CHECK
  bool need_check_set = false;
  int totscene = 0;
#endif

  for (Scene *sce = main->scenes.first; sce; sce = sce->id.next) {
    if (sce->id.tag & LIB_TAG_NEED_LINK) {
      /* Link ID Properties -- and copy this comment EXACTLY for easy finding
       * of library blocks that implement this.*/
      IDP_LibLinkProperty(sce->id.properties, fd);
      lib_link_animdata(fd, &sce->id, sce->adt);

      lib_link_keyingsets(fd, &sce->id, &sce->keyingsets);

      sce->camera = newlibadr(fd, sce->id.lib, sce->camera);
      sce->world = newlibadr_us(fd, sce->id.lib, sce->world);
      sce->set = newlibadr(fd, sce->id.lib, sce->set);
      sce->gpd = newlibadr_us(fd, sce->id.lib, sce->gpd);

      link_paint(fd, sce, &sce->toolsettings->imapaint.paint);
      if (sce->toolsettings->sculpt) {
        link_paint(fd, sce, &sce->toolsettings->sculpt->paint);
      }
      if (sce->toolsettings->vpaint) {
        link_paint(fd, sce, &sce->toolsettings->vpaint->paint);
      }
      if (sce->toolsettings->wpaint) {
        link_paint(fd, sce, &sce->toolsettings->wpaint->paint);
      }
      if (sce->toolsettings->uvsculpt) {
        link_paint(fd, sce, &sce->toolsettings->uvsculpt->paint);
      }
      if (sce->toolsettings->gp_paint) {
        link_paint(fd, sce, &sce->toolsettings->gp_paint->paint);
      }

      if (sce->toolsettings->sculpt) {
        sce->toolsettings->sculpt->gravity_object = newlibadr(
            fd, sce->id.lib, sce->toolsettings->sculpt->gravity_object);
      }

      if (sce->toolsettings->imapaint.stencil) {
        sce->toolsettings->imapaint.stencil = newlibadr_us(
            fd, sce->id.lib, sce->toolsettings->imapaint.stencil);
      }

      if (sce->toolsettings->imapaint.clone) {
        sce->toolsettings->imapaint.clone = newlibadr_us(
            fd, sce->id.lib, sce->toolsettings->imapaint.clone);
      }

      if (sce->toolsettings->imapaint.canvas) {
        sce->toolsettings->imapaint.canvas = newlibadr_us(
            fd, sce->id.lib, sce->toolsettings->imapaint.canvas);
      }

      sce->toolsettings->particle.shape_object = newlibadr(
          fd, sce->id.lib, sce->toolsettings->particle.shape_object);

      sce->toolsettings->gp_sculpt.guide.reference_object = newlibadr(
          fd, sce->id.lib, sce->toolsettings->gp_sculpt.guide.reference_object);

      for (Base *base_legacy_next, *base_legacy = sce->base.first; base_legacy;
           base_legacy = base_legacy_next) {
        base_legacy_next = base_legacy->next;

        base_legacy->object = newlibadr_us(fd, sce->id.lib, base_legacy->object);

        if (base_legacy->object == NULL) {
          blo_reportf_wrap(fd->reports,
                           RPT_WARNING,
                           TIP_("LIB: object lost from scene: '%s'"),
                           sce->id.name + 2);
          BLI_remlink(&sce->base, base_legacy);
          if (base_legacy == sce->basact) {
            sce->basact = NULL;
          }
          MEM_freeN(base_legacy);
        }
      }

      Sequence *seq;
      SEQ_BEGIN (sce->ed, seq) {
        IDP_LibLinkProperty(seq->prop, fd);

        if (seq->ipo) {
          seq->ipo = newlibadr_us(
              fd, sce->id.lib, seq->ipo);  // XXX deprecated - old animation system
        }
        seq->scene_sound = NULL;
        if (seq->scene) {
          seq->scene = newlibadr(fd, sce->id.lib, seq->scene);
          seq->scene_sound = NULL;
        }
        if (seq->clip) {
          seq->clip = newlibadr_us(fd, sce->id.lib, seq->clip);
        }
        if (seq->mask) {
          seq->mask = newlibadr_us(fd, sce->id.lib, seq->mask);
        }
        if (seq->scene_camera) {
          seq->scene_camera = newlibadr(fd, sce->id.lib, seq->scene_camera);
        }
        if (seq->sound) {
          seq->scene_sound = NULL;
          if (seq->type == SEQ_TYPE_SOUND_HD) {
            seq->type = SEQ_TYPE_SOUND_RAM;
          }
          else {
            seq->sound = newlibadr(fd, sce->id.lib, seq->sound);
          }
          if (seq->sound) {
            id_us_plus_no_lib((ID *)seq->sound);
            seq->scene_sound = NULL;
          }
        }
        if (seq->type == SEQ_TYPE_TEXT) {
          TextVars *t = seq->effectdata;
          t->text_font = newlibadr_us(fd, sce->id.lib, t->text_font);
        }
        BLI_listbase_clear(&seq->anims);

        lib_link_sequence_modifiers(fd, sce, &seq->modifiers);
      }
      SEQ_END;

      for (TimeMarker *marker = sce->markers.first; marker; marker = marker->next) {
        if (marker->camera) {
          marker->camera = newlibadr(fd, sce->id.lib, marker->camera);
        }
      }

      /* rigidbody world relies on it's linked collections */
      if (sce->rigidbody_world) {
        RigidBodyWorld *rbw = sce->rigidbody_world;
        if (rbw->group) {
          rbw->group = newlibadr(fd, sce->id.lib, rbw->group);
        }
        if (rbw->constraints) {
          rbw->constraints = newlibadr(fd, sce->id.lib, rbw->constraints);
        }
        if (rbw->effector_weights) {
          rbw->effector_weights->group = newlibadr(fd, sce->id.lib, rbw->effector_weights->group);
        }
      }

      if (sce->nodetree) {
        lib_link_ntree(fd, &sce->id, sce->nodetree);
        sce->nodetree->id.lib = sce->id.lib;
        composite_patch(sce->nodetree, sce);
      }

      for (SceneRenderLayer *srl = sce->r.layers.first; srl; srl = srl->next) {
        srl->mat_override = newlibadr_us(fd, sce->id.lib, srl->mat_override);
        for (FreestyleModuleConfig *fmc = srl->freestyleConfig.modules.first; fmc;
             fmc = fmc->next) {
          fmc->script = newlibadr(fd, sce->id.lib, fmc->script);
        }
        for (FreestyleLineSet *fls = srl->freestyleConfig.linesets.first; fls; fls = fls->next) {
          fls->linestyle = newlibadr_us(fd, sce->id.lib, fls->linestyle);
          fls->group = newlibadr_us(fd, sce->id.lib, fls->group);
        }
      }
      /* Motion Tracking */
      sce->clip = newlibadr_us(fd, sce->id.lib, sce->clip);

#ifdef USE_COLLECTION_COMPAT_28
      if (sce->collection) {
        lib_link_scene_collection(fd, sce->id.lib, sce->collection);
      }
#endif

      if (sce->master_collection) {
        lib_link_collection_data(fd, sce->id.lib, sce->master_collection);
      }

      for (ViewLayer *view_layer = sce->view_layers.first; view_layer;
           view_layer = view_layer->next) {
        lib_link_view_layer(fd, sce->id.lib, view_layer);
      }

      if (sce->r.bake.cage_object) {
        sce->r.bake.cage_object = newlibadr(fd, sce->id.lib, sce->r.bake.cage_object);
      }

#ifdef USE_SETSCENE_CHECK
      if (sce->set != NULL) {
        /* link flag for scenes with set would be reset later,
         * so this way we only check cyclic for newly linked scenes.
         */
        need_check_set = true;
      }
      else {
        /* postpone un-setting the flag until we've checked the set-scene */
        sce->id.tag &= ~LIB_TAG_NEED_LINK;
      }
#else
      sce->id.tag &= ~LIB_TAG_NEED_LINK;
#endif
    }

#ifdef USE_SETSCENE_CHECK
    totscene++;
#endif
  }

#ifdef USE_SETSCENE_CHECK
  if (need_check_set) {
    for (Scene *sce = main->scenes.first; sce; sce = sce->id.next) {
      if (sce->id.tag & LIB_TAG_NEED_LINK) {
        sce->id.tag &= ~LIB_TAG_NEED_LINK;
        if (!scene_validate_setscene__liblink(sce, totscene)) {
          printf("Found cyclic background scene when linking %s\n", sce->id.name + 2);
        }
      }
    }
  }
#endif
}

#undef USE_SETSCENE_CHECK

static void link_recurs_seq(FileData *fd, ListBase *lb)
{
  Sequence *seq;

  link_list(fd, lb);

  for (seq = lb->first; seq; seq = seq->next) {
    if (seq->seqbase.first) {
      link_recurs_seq(fd, &seq->seqbase);
    }
  }
}

static void direct_link_paint(FileData *fd, const Scene *scene, Paint *p)
{
  if (p->num_input_samples < 1) {
    p->num_input_samples = 1;
  }

  p->cavity_curve = newdataadr(fd, p->cavity_curve);
  if (p->cavity_curve) {
    direct_link_curvemapping(fd, p->cavity_curve);
  }
  else {
    BKE_paint_cavity_curve_preset(p, CURVE_PRESET_LINE);
  }

  p->tool_slots = newdataadr(fd, p->tool_slots);

  /* Workaround for invalid data written in older versions. */
  const size_t expected_size = sizeof(PaintToolSlot) * p->tool_slots_len;
  if (p->tool_slots && MEM_allocN_len(p->tool_slots) < expected_size) {
    MEM_freeN(p->tool_slots);
    p->tool_slots = MEM_callocN(expected_size, "PaintToolSlot");
  }

  BKE_paint_runtime_init(scene->toolsettings, p);
}

static void direct_link_paint_helper(FileData *fd, const Scene *scene, Paint **paint)
{
  /* TODO. is this needed */
  (*paint) = newdataadr(fd, (*paint));

  if (*paint) {
    direct_link_paint(fd, scene, *paint);
  }
}

static void direct_link_sequence_modifiers(FileData *fd, ListBase *lb)
{
  SequenceModifierData *smd;

  link_list(fd, lb);

  for (smd = lb->first; smd; smd = smd->next) {
    if (smd->mask_sequence) {
      smd->mask_sequence = newdataadr(fd, smd->mask_sequence);
    }

    if (smd->type == seqModifierType_Curves) {
      CurvesModifierData *cmd = (CurvesModifierData *)smd;

      direct_link_curvemapping(fd, &cmd->curve_mapping);
    }
    else if (smd->type == seqModifierType_HueCorrect) {
      HueCorrectModifierData *hcmd = (HueCorrectModifierData *)smd;

      direct_link_curvemapping(fd, &hcmd->curve_mapping);
    }
  }
}

static void direct_link_scene(FileData *fd, Scene *sce)
{
  Editing *ed;
  Sequence *seq;
  MetaStack *ms;
  RigidBodyWorld *rbw;
  ViewLayer *view_layer;
  SceneRenderLayer *srl;

  sce->depsgraph_hash = NULL;
  sce->fps_info = NULL;

  memset(&sce->customdata_mask, 0, sizeof(sce->customdata_mask));
  memset(&sce->customdata_mask_modal, 0, sizeof(sce->customdata_mask_modal));

  BKE_sound_reset_scene_runtime(sce);

  /* set users to one by default, not in lib-link, this will increase it for compo nodes */
  id_us_ensure_real(&sce->id);

  link_list(fd, &(sce->base));

  sce->adt = newdataadr(fd, sce->adt);
  direct_link_animdata(fd, sce->adt);

  link_list(fd, &sce->keyingsets);
  direct_link_keyingsets(fd, &sce->keyingsets);

  sce->basact = newdataadr(fd, sce->basact);

  sce->toolsettings = newdataadr(fd, sce->toolsettings);
  if (sce->toolsettings) {
    direct_link_paint_helper(fd, sce, (Paint **)&sce->toolsettings->sculpt);
    direct_link_paint_helper(fd, sce, (Paint **)&sce->toolsettings->vpaint);
    direct_link_paint_helper(fd, sce, (Paint **)&sce->toolsettings->wpaint);
    direct_link_paint_helper(fd, sce, (Paint **)&sce->toolsettings->uvsculpt);
    direct_link_paint_helper(fd, sce, (Paint **)&sce->toolsettings->gp_paint);

    direct_link_paint(fd, sce, &sce->toolsettings->imapaint.paint);

    sce->toolsettings->imapaint.paintcursor = NULL;
    sce->toolsettings->particle.paintcursor = NULL;
    sce->toolsettings->particle.scene = NULL;
    sce->toolsettings->particle.object = NULL;
    sce->toolsettings->gp_sculpt.paintcursor = NULL;

    /* relink grease pencil interpolation curves */
    sce->toolsettings->gp_interpolate.custom_ipo = newdataadr(
        fd, sce->toolsettings->gp_interpolate.custom_ipo);
    if (sce->toolsettings->gp_interpolate.custom_ipo) {
      direct_link_curvemapping(fd, sce->toolsettings->gp_interpolate.custom_ipo);
    }
    /* relink grease pencil multiframe falloff curve */
    sce->toolsettings->gp_sculpt.cur_falloff = newdataadr(
        fd, sce->toolsettings->gp_sculpt.cur_falloff);
    if (sce->toolsettings->gp_sculpt.cur_falloff) {
      direct_link_curvemapping(fd, sce->toolsettings->gp_sculpt.cur_falloff);
    }
    /* relink grease pencil primitive curve */
    sce->toolsettings->gp_sculpt.cur_primitive = newdataadr(
        fd, sce->toolsettings->gp_sculpt.cur_primitive);
    if (sce->toolsettings->gp_sculpt.cur_primitive) {
      direct_link_curvemapping(fd, sce->toolsettings->gp_sculpt.cur_primitive);
    }
  }

  if (sce->ed) {
    ListBase *old_seqbasep = &sce->ed->seqbase;

    ed = sce->ed = newdataadr(fd, sce->ed);

    ed->act_seq = newdataadr(fd, ed->act_seq);
    ed->cache = NULL;

    /* recursive link sequences, lb will be correctly initialized */
    link_recurs_seq(fd, &ed->seqbase);

    SEQ_BEGIN (ed, seq) {
      seq->seq1 = newdataadr(fd, seq->seq1);
      seq->seq2 = newdataadr(fd, seq->seq2);
      seq->seq3 = newdataadr(fd, seq->seq3);

      /* a patch: after introduction of effects with 3 input strips */
      if (seq->seq3 == NULL) {
        seq->seq3 = seq->seq2;
      }

      seq->effectdata = newdataadr(fd, seq->effectdata);
      seq->stereo3d_format = newdataadr(fd, seq->stereo3d_format);

      if (seq->type & SEQ_TYPE_EFFECT) {
        seq->flag |= SEQ_EFFECT_NOT_LOADED;
      }

      if (seq->type == SEQ_TYPE_SPEED) {
        SpeedControlVars *s = seq->effectdata;
        s->frameMap = NULL;
      }

      if (seq->type == SEQ_TYPE_TEXT) {
        TextVars *t = seq->effectdata;
        t->text_blf_id = SEQ_FONT_NOT_LOADED;
      }

      seq->prop = newdataadr(fd, seq->prop);
      IDP_DirectLinkGroup_OrFree(&seq->prop, (fd->flags & FD_FLAGS_SWITCH_ENDIAN), fd);

      seq->strip = newdataadr(fd, seq->strip);
      if (seq->strip && seq->strip->done == 0) {
        seq->strip->done = true;

        if (ELEM(seq->type,
                 SEQ_TYPE_IMAGE,
                 SEQ_TYPE_MOVIE,
                 SEQ_TYPE_SOUND_RAM,
                 SEQ_TYPE_SOUND_HD)) {
          seq->strip->stripdata = newdataadr(fd, seq->strip->stripdata);
        }
        else {
          seq->strip->stripdata = NULL;
        }
        seq->strip->crop = newdataadr(fd, seq->strip->crop);
        seq->strip->transform = newdataadr(fd, seq->strip->transform);
        seq->strip->proxy = newdataadr(fd, seq->strip->proxy);
        if (seq->strip->proxy) {
          seq->strip->proxy->anim = NULL;
        }
        else if (seq->flag & SEQ_USE_PROXY) {
          BKE_sequencer_proxy_set(seq, true);
        }

        /* need to load color balance to it could be converted to modifier */
        seq->strip->color_balance = newdataadr(fd, seq->strip->color_balance);
      }

      direct_link_sequence_modifiers(fd, &seq->modifiers);
    }
    SEQ_END;

    /* link metastack, slight abuse of structs here,
     * have to restore pointer to internal part in struct */
    {
      Sequence temp;
      void *poin;
      intptr_t offset;

      offset = ((intptr_t) & (temp.seqbase)) - ((intptr_t)&temp);

      /* root pointer */
      if (ed->seqbasep == old_seqbasep) {
        ed->seqbasep = &ed->seqbase;
      }
      else {
        poin = POINTER_OFFSET(ed->seqbasep, -offset);

        poin = newdataadr(fd, poin);
        if (poin) {
          ed->seqbasep = (ListBase *)POINTER_OFFSET(poin, offset);
        }
        else {
          ed->seqbasep = &ed->seqbase;
        }
      }
      /* stack */
      link_list(fd, &(ed->metastack));

      for (ms = ed->metastack.first; ms; ms = ms->next) {
        ms->parseq = newdataadr(fd, ms->parseq);

        if (ms->oldbasep == old_seqbasep) {
          ms->oldbasep = &ed->seqbase;
        }
        else {
          poin = POINTER_OFFSET(ms->oldbasep, -offset);
          poin = newdataadr(fd, poin);
          if (poin) {
            ms->oldbasep = (ListBase *)POINTER_OFFSET(poin, offset);
          }
          else {
            ms->oldbasep = &ed->seqbase;
          }
        }
      }
    }
  }

#ifdef DURIAN_CAMERA_SWITCH
  /* Runtime */
  sce->r.mode &= ~R_NO_CAMERA_SWITCH;
#endif

  sce->r.avicodecdata = newdataadr(fd, sce->r.avicodecdata);
  if (sce->r.avicodecdata) {
    sce->r.avicodecdata->lpFormat = newdataadr(fd, sce->r.avicodecdata->lpFormat);
    sce->r.avicodecdata->lpParms = newdataadr(fd, sce->r.avicodecdata->lpParms);
  }
  if (sce->r.ffcodecdata.properties) {
    sce->r.ffcodecdata.properties = newdataadr(fd, sce->r.ffcodecdata.properties);
    IDP_DirectLinkGroup_OrFree(
        &sce->r.ffcodecdata.properties, (fd->flags & FD_FLAGS_SWITCH_ENDIAN), fd);
  }

  link_list(fd, &(sce->markers));
  link_list(fd, &(sce->transform_spaces));
  link_list(fd, &(sce->r.layers));
  link_list(fd, &(sce->r.views));

  for (srl = sce->r.layers.first; srl; srl = srl->next) {
    srl->prop = newdataadr(fd, srl->prop);
    IDP_DirectLinkGroup_OrFree(&srl->prop, (fd->flags & FD_FLAGS_SWITCH_ENDIAN), fd);
    link_list(fd, &(srl->freestyleConfig.modules));
    link_list(fd, &(srl->freestyleConfig.linesets));
  }

  sce->nodetree = newdataadr(fd, sce->nodetree);
  if (sce->nodetree) {
    direct_link_id(fd, &sce->nodetree->id);
    direct_link_nodetree(fd, sce->nodetree);
  }

  direct_link_view_settings(fd, &sce->view_settings);

  sce->rigidbody_world = newdataadr(fd, sce->rigidbody_world);
  rbw = sce->rigidbody_world;
  if (rbw) {
    rbw->shared = newdataadr(fd, rbw->shared);

    if (rbw->shared == NULL) {
      /* Link deprecated caches if they exist, so we can use them for versioning.
       * We should only do this when rbw->shared == NULL, because those pointers
       * are always set (for compatibility with older Blenders). We mustn't link
       * the same pointcache twice. */
      direct_link_pointcache_list(fd, &rbw->ptcaches, &rbw->pointcache, false);

      /* make sure simulation starts from the beginning after loading file */
      if (rbw->pointcache) {
        rbw->ltime = (float)rbw->pointcache->startframe;
      }
    }
    else {
      /* must nullify the reference to physics sim object, since it no-longer exist
       * (and will need to be recalculated)
       */
      rbw->shared->physics_world = NULL;

      /* link caches */
      direct_link_pointcache_list(fd, &rbw->shared->ptcaches, &rbw->shared->pointcache, false);

      /* make sure simulation starts from the beginning after loading file */
      if (rbw->shared->pointcache) {
        rbw->ltime = (float)rbw->shared->pointcache->startframe;
      }
    }
    rbw->objects = NULL;
    rbw->numbodies = 0;

    /* set effector weights */
    rbw->effector_weights = newdataadr(fd, rbw->effector_weights);
    if (!rbw->effector_weights) {
      rbw->effector_weights = BKE_effector_add_weights(NULL);
    }
  }

  sce->preview = direct_link_preview_image(fd, sce->preview);

  direct_link_curvemapping(fd, &sce->r.mblur_shutter_curve);

#ifdef USE_COLLECTION_COMPAT_28
  /* this runs before the very first doversion */
  if (sce->collection) {
    sce->collection = newdataadr(fd, sce->collection);
    direct_link_scene_collection(fd, sce->collection);
  }
#endif

  if (sce->master_collection) {
    sce->master_collection = newdataadr(fd, sce->master_collection);
    /* Needed because this is an ID outside of Main. */
    direct_link_id(fd, &sce->master_collection->id);
    direct_link_collection(fd, sce->master_collection);
  }

  /* insert into global old-new map for reading without UI (link_global accesses it again) */
  link_glob_list(fd, &sce->view_layers);
  for (view_layer = sce->view_layers.first; view_layer; view_layer = view_layer->next) {
    direct_link_view_layer(fd, view_layer);
  }

  if (fd->memfile) {
    /* If it's undo try to recover the cache. */
    if (fd->scenemap) {
      sce->eevee.light_cache = newsceadr(fd, sce->eevee.light_cache);
    }
    else {
      sce->eevee.light_cache = NULL;
    }
  }
  else {
    /* else try to read the cache from file. */
    sce->eevee.light_cache = newdataadr(fd, sce->eevee.light_cache);
    if (sce->eevee.light_cache) {
      direct_link_lightcache(fd, sce->eevee.light_cache);
    }
  }

  sce->layer_properties = newdataadr(fd, sce->layer_properties);
  IDP_DirectLinkGroup_OrFree(&sce->layer_properties, (fd->flags & FD_FLAGS_SWITCH_ENDIAN), fd);
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Read ID: Grease Pencil
 * \{ */

/* relink's grease pencil data's refs */
static void lib_link_gpencil(FileData *fd, Main *main)
{
  /* Relink all data-lock linked by GP data-lock */
  for (bGPdata *gpd = main->gpencils.first; gpd; gpd = gpd->id.next) {
    if (gpd->id.tag & LIB_TAG_NEED_LINK) {
      /* Layers */
      for (bGPDlayer *gpl = gpd->layers.first; gpl; gpl = gpl->next) {
        /* Layer -> Parent References */
        gpl->parent = newlibadr(fd, gpd->id.lib, gpl->parent);
      }

      /* Data-block Stuff */
      IDP_LibLinkProperty(gpd->id.properties, fd);
      lib_link_animdata(fd, &gpd->id, gpd->adt);

      /* materials */
      for (int a = 0; a < gpd->totcol; a++) {
        gpd->mat[a] = newlibadr_us(fd, gpd->id.lib, gpd->mat[a]);
      }

      gpd->id.tag &= ~LIB_TAG_NEED_LINK;
    }
  }
}

/* relinks grease-pencil data - used for direct_link and old file linkage */
static void direct_link_gpencil(FileData *fd, bGPdata *gpd)
{
  bGPDlayer *gpl;
  bGPDframe *gpf;
  bGPDstroke *gps;
  bGPDpalette *palette;

  /* we must firstly have some grease-pencil data to link! */
  if (gpd == NULL) {
    return;
  }

  /* relink animdata */
  gpd->adt = newdataadr(fd, gpd->adt);
  direct_link_animdata(fd, gpd->adt);

  /* init stroke buffer */
  gpd->runtime.sbuffer = NULL;
  gpd->runtime.sbuffer_used = 0;
  gpd->runtime.sbuffer_size = 0;
  gpd->runtime.tot_cp_points = 0;

  /* relink palettes (old palettes deprecated, only to convert old files) */
  link_list(fd, &gpd->palettes);
  if (gpd->palettes.first != NULL) {
    for (palette = gpd->palettes.first; palette; palette = palette->next) {
      link_list(fd, &palette->colors);
    }
  }

  /* materials */
  gpd->mat = newdataadr(fd, gpd->mat);
  test_pointer_array(fd, (void **)&gpd->mat);

  /* relink layers */
  link_list(fd, &gpd->layers);

  for (gpl = gpd->layers.first; gpl; gpl = gpl->next) {
    /* relink frames */
    link_list(fd, &gpl->frames);

    gpl->actframe = newdataadr(fd, gpl->actframe);

    gpl->runtime.icon_id = 0;

    for (gpf = gpl->frames.first; gpf; gpf = gpf->next) {
      /* relink strokes (and their points) */
      link_list(fd, &gpf->strokes);

      for (gps = gpf->strokes.first; gps; gps = gps->next) {
        /* relink stroke points array */
        gps->points = newdataadr(fd, gps->points);

        /* relink weight data */
        if (gps->dvert) {
          gps->dvert = newdataadr(fd, gps->dvert);
          direct_link_dverts(fd, gps->totpoints, gps->dvert);
        }

        /* the triangulation is not saved, so need to be recalculated */
        gps->triangles = NULL;
        gps->tot_triangles = 0;
        gps->flag |= GP_STROKE_RECALC_GEOMETRY;
      }
    }
  }
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Read Screen Area/Region (Screen Data)
 * \{ */

static void direct_link_panel_list(FileData *fd, ListBase *lb)
{
  link_list(fd, lb);

  for (Panel *pa = lb->first; pa; pa = pa->next) {
    pa->runtime_flag = 0;
    pa->activedata = NULL;
    pa->type = NULL;
    direct_link_panel_list(fd, &pa->children);
  }
}

static void direct_link_region(FileData *fd, ARegion *ar, int spacetype)
{
  uiList *ui_list;

  direct_link_panel_list(fd, &ar->panels);

  link_list(fd, &ar->panels_category_active);

  link_list(fd, &ar->ui_lists);

  for (ui_list = ar->ui_lists.first; ui_list; ui_list = ui_list->next) {
    ui_list->type = NULL;
    ui_list->dyn_data = NULL;
    ui_list->properties = newdataadr(fd, ui_list->properties);
    IDP_DirectLinkGroup_OrFree(&ui_list->properties, (fd->flags & FD_FLAGS_SWITCH_ENDIAN), fd);
  }

  link_list(fd, &ar->ui_previews);

  if (spacetype == SPACE_EMPTY) {
    /* unknown space type, don't leak regiondata */
    ar->regiondata = NULL;
  }
  else if (ar->flag & RGN_FLAG_TEMP_REGIONDATA) {
    /* Runtime data, don't use. */
    ar->regiondata = NULL;
  }
  else {
    ar->regiondata = newdataadr(fd, ar->regiondata);
    if (ar->regiondata) {
      if (spacetype == SPACE_VIEW3D) {
        RegionView3D *rv3d = ar->regiondata;

        rv3d->localvd = newdataadr(fd, rv3d->localvd);
        rv3d->clipbb = newdataadr(fd, rv3d->clipbb);

        rv3d->depths = NULL;
        rv3d->render_engine = NULL;
        rv3d->sms = NULL;
        rv3d->smooth_timer = NULL;
      }
    }
  }

  ar->v2d.tab_offset = NULL;
  ar->v2d.tab_num = 0;
  ar->v2d.tab_cur = 0;
  ar->v2d.sms = NULL;
  ar->v2d.alpha_hor = ar->v2d.alpha_vert = 255; /* visible by default */
  BLI_listbase_clear(&ar->panels_category);
  BLI_listbase_clear(&ar->handlers);
  BLI_listbase_clear(&ar->uiblocks);
  ar->headerstr = NULL;
  ar->visible = 0;
  ar->type = NULL;
  ar->do_draw = 0;
  ar->gizmo_map = NULL;
  ar->regiontimer = NULL;
  ar->draw_buffer = NULL;
  memset(&ar->drawrct, 0, sizeof(ar->drawrct));
}

static void direct_link_area(FileData *fd, ScrArea *area)
{
  SpaceLink *sl;
  ARegion *ar;

  link_list(fd, &(area->spacedata));
  link_list(fd, &(area->regionbase));

  BLI_listbase_clear(&area->handlers);
  area->type = NULL; /* spacetype callbacks */

  /* Should always be unset so that rna_Area_type_get works correctly. */
  area->butspacetype = SPACE_EMPTY;

  area->region_active_win = -1;

  area->flag &= ~AREA_FLAG_ACTIVE_TOOL_UPDATE;

  area->global = newdataadr(fd, area->global);

  /* if we do not have the spacetype registered we cannot
   * free it, so don't allocate any new memory for such spacetypes. */
  if (!BKE_spacetype_exists(area->spacetype)) {
    /* Hint for versioning code to replace deprecated space types. */
    area->butspacetype = area->spacetype;

    area->spacetype = SPACE_EMPTY;
  }

  for (ar = area->regionbase.first; ar; ar = ar->next) {
    direct_link_region(fd, ar, area->spacetype);
  }

  /* accident can happen when read/save new file with older version */
  /* 2.50: we now always add spacedata for info */
  if (area->spacedata.first == NULL) {
    SpaceInfo *sinfo = MEM_callocN(sizeof(SpaceInfo), "spaceinfo");
    area->spacetype = sinfo->spacetype = SPACE_INFO;
    BLI_addtail(&area->spacedata, sinfo);
  }
  /* add local view3d too */
  else if (area->spacetype == SPACE_VIEW3D) {
    blo_do_versions_view3d_split_250(area->spacedata.first, &area->regionbase);
  }

  for (sl = area->spacedata.first; sl; sl = sl->next) {
    link_list(fd, &(sl->regionbase));

    /* if we do not have the spacetype registered we cannot
     * free it, so don't allocate any new memory for such spacetypes. */
    if (!BKE_spacetype_exists(sl->spacetype)) {
      sl->spacetype = SPACE_EMPTY;
    }

    for (ar = sl->regionbase.first; ar; ar = ar->next) {
      direct_link_region(fd, ar, sl->spacetype);
    }

    if (sl->spacetype == SPACE_VIEW3D) {
      View3D *v3d = (View3D *)sl;

      v3d->flag |= V3D_INVALID_BACKBUF;

      if (v3d->gpd) {
        v3d->gpd = newdataadr(fd, v3d->gpd);
        direct_link_gpencil(fd, v3d->gpd);
      }
      v3d->localvd = newdataadr(fd, v3d->localvd);
      v3d->runtime.properties_storage = NULL;

      /* render can be quite heavy, set to solid on load */
      if (v3d->shading.type == OB_RENDER) {
        v3d->shading.type = OB_SOLID;
      }
      v3d->shading.prev_type = OB_SOLID;

      if (v3d->fx_settings.dof) {
        v3d->fx_settings.dof = newdataadr(fd, v3d->fx_settings.dof);
      }
      if (v3d->fx_settings.ssao) {
        v3d->fx_settings.ssao = newdataadr(fd, v3d->fx_settings.ssao);
      }

      blo_do_versions_view3d_split_250(v3d, &sl->regionbase);
    }
    else if (sl->spacetype == SPACE_GRAPH) {
      SpaceGraph *sipo = (SpaceGraph *)sl;

      sipo->ads = newdataadr(fd, sipo->ads);
      BLI_listbase_clear(&sipo->runtime.ghost_curves);
    }
    else if (sl->spacetype == SPACE_NLA) {
      SpaceNla *snla = (SpaceNla *)sl;

      snla->ads = newdataadr(fd, snla->ads);
    }
    else if (sl->spacetype == SPACE_OUTLINER) {
      SpaceOutliner *soops = (SpaceOutliner *)sl;

      /* use newdataadr_no_us and do not free old memory avoiding double
       * frees and use of freed memory. this could happen because of a
       * bug fixed in revision 58959 where the treestore memory address
       * was not unique */
      TreeStore *ts = newdataadr_no_us(fd, soops->treestore);
      soops->treestore = NULL;
      if (ts) {
        TreeStoreElem *elems = newdataadr_no_us(fd, ts->data);

        soops->treestore = BLI_mempool_create(
            sizeof(TreeStoreElem), ts->usedelem, 512, BLI_MEMPOOL_ALLOW_ITER);
        if (ts->usedelem && elems) {
          int i;
          for (i = 0; i < ts->usedelem; i++) {
            TreeStoreElem *new_elem = BLI_mempool_alloc(soops->treestore);
            *new_elem = elems[i];
          }
        }
        /* we only saved what was used */
        soops->storeflag |= SO_TREESTORE_CLEANUP;  // at first draw
      }
      soops->treehash = NULL;
      soops->tree.first = soops->tree.last = NULL;
    }
    else if (sl->spacetype == SPACE_IMAGE) {
      SpaceImage *sima = (SpaceImage *)sl;

      sima->iuser.scene = NULL;
      sima->iuser.ok = 1;
      sima->scopes.waveform_1 = NULL;
      sima->scopes.waveform_2 = NULL;
      sima->scopes.waveform_3 = NULL;
      sima->scopes.vecscope = NULL;
      sima->scopes.ok = 0;

      /* WARNING: gpencil data is no longer stored directly in sima after 2.5
       * so sacrifice a few old files for now to avoid crashes with new files!
       * committed: r28002 */
#if 0
      sima->gpd = newdataadr(fd, sima->gpd);
      if (sima->gpd) {
        direct_link_gpencil(fd, sima->gpd);
      }
#endif
    }
    else if (sl->spacetype == SPACE_NODE) {
      SpaceNode *snode = (SpaceNode *)sl;

      if (snode->gpd) {
        snode->gpd = newdataadr(fd, snode->gpd);
        direct_link_gpencil(fd, snode->gpd);
      }

      link_list(fd, &snode->treepath);
      snode->edittree = NULL;
      snode->iofsd = NULL;
      BLI_listbase_clear(&snode->linkdrag);
    }
    else if (sl->spacetype == SPACE_TEXT) {
      SpaceText *st = (SpaceText *)sl;

      st->drawcache = NULL;
      st->scroll_accum[0] = 0.0f;
      st->scroll_accum[1] = 0.0f;
    }
    else if (sl->spacetype == SPACE_SEQ) {
      SpaceSeq *sseq = (SpaceSeq *)sl;

      /* grease pencil data is not a direct data and can't be linked from direct_link*
       * functions, it should be linked from lib_link* functions instead
       *
       * otherwise it'll lead to lost grease data on open because it'll likely be
       * read from file after all other users of grease pencil and newdataadr would
       * simple return NULL here (sergey)
       */
#if 0
      if (sseq->gpd) {
        sseq->gpd = newdataadr(fd, sseq->gpd);
        direct_link_gpencil(fd, sseq->gpd);
      }
#endif
      sseq->scopes.reference_ibuf = NULL;
      sseq->scopes.zebra_ibuf = NULL;
      sseq->scopes.waveform_ibuf = NULL;
      sseq->scopes.sep_waveform_ibuf = NULL;
      sseq->scopes.vector_ibuf = NULL;
      sseq->scopes.histogram_ibuf = NULL;
      sseq->compositor = NULL;
    }
    else if (sl->spacetype == SPACE_PROPERTIES) {
      SpaceProperties *sbuts = (SpaceProperties *)sl;

      sbuts->path = NULL;
      sbuts->texuser = NULL;
      sbuts->mainbo = sbuts->mainb;
      sbuts->mainbuser = sbuts->mainb;
    }
    else if (sl->spacetype == SPACE_CONSOLE) {
      SpaceConsole *sconsole = (SpaceConsole *)sl;
      ConsoleLine *cl, *cl_next;

      link_list(fd, &sconsole->scrollback);
      link_list(fd, &sconsole->history);

      // for (cl= sconsole->scrollback.first; cl; cl= cl->next)
      //  cl->line= newdataadr(fd, cl->line);

      /* comma expressions, (e.g. expr1, expr2, expr3) evaluate each expression,
       * from left to right.  the right-most expression sets the result of the comma
       * expression as a whole*/
      for (cl = sconsole->history.first; cl; cl = cl_next) {
        cl_next = cl->next;
        cl->line = newdataadr(fd, cl->line);
        if (cl->line) {
          /* the allocted length is not written, so reset here */
          cl->len_alloc = cl->len + 1;
        }
        else {
          BLI_remlink(&sconsole->history, cl);
          MEM_freeN(cl);
        }
      }
    }
    else if (sl->spacetype == SPACE_FILE) {
      SpaceFile *sfile = (SpaceFile *)sl;

      /* this sort of info is probably irrelevant for reloading...
       * plus, it isn't saved to files yet!
       */
      sfile->folders_prev = sfile->folders_next = NULL;
      sfile->files = NULL;
      sfile->layout = NULL;
      sfile->op = NULL;
      sfile->previews_timer = NULL;
      sfile->params = newdataadr(fd, sfile->params);
    }
    else if (sl->spacetype == SPACE_CLIP) {
      SpaceClip *sclip = (SpaceClip *)sl;

      sclip->scopes.track_search = NULL;
      sclip->scopes.track_preview = NULL;
      sclip->scopes.ok = 0;
    }
  }

  BLI_listbase_clear(&area->actionzones);

  area->v1 = newdataadr(fd, area->v1);
  area->v2 = newdataadr(fd, area->v2);
  area->v3 = newdataadr(fd, area->v3);
  area->v4 = newdataadr(fd, area->v4);
}

static void lib_link_area(FileData *fd, ID *parent_id, ScrArea *area)
{
  area->full = newlibadr(fd, parent_id->lib, area->full);

  memset(&area->runtime, 0x0, sizeof(area->runtime));

  for (SpaceLink *sl = area->spacedata.first; sl; sl = sl->next) {
    switch (sl->spacetype) {
      case SPACE_VIEW3D: {
        View3D *v3d = (View3D *)sl;

        v3d->camera = newlibadr(fd, parent_id->lib, v3d->camera);
        v3d->ob_centre = newlibadr(fd, parent_id->lib, v3d->ob_centre);

        if (v3d->localvd) {
          v3d->localvd->camera = newlibadr(fd, parent_id->lib, v3d->localvd->camera);
        }
        break;
      }
      case SPACE_GRAPH: {
        SpaceGraph *sipo = (SpaceGraph *)sl;
        bDopeSheet *ads = sipo->ads;

        if (ads) {
          ads->source = newlibadr(fd, parent_id->lib, ads->source);
          ads->filter_grp = newlibadr(fd, parent_id->lib, ads->filter_grp);
        }
        break;
      }
      case SPACE_PROPERTIES: {
        SpaceProperties *sbuts = (SpaceProperties *)sl;
        sbuts->pinid = newlibadr(fd, parent_id->lib, sbuts->pinid);
        if (sbuts->pinid == NULL) {
          sbuts->flag &= ~SB_PIN_CONTEXT;
        }
        break;
      }
      case SPACE_FILE:
        break;
      case SPACE_ACTION: {
        SpaceAction *saction = (SpaceAction *)sl;
        bDopeSheet *ads = &saction->ads;

        if (ads) {
          ads->source = newlibadr(fd, parent_id->lib, ads->source);
          ads->filter_grp = newlibadr(fd, parent_id->lib, ads->filter_grp);
        }

        saction->action = newlibadr(fd, parent_id->lib, saction->action);
        break;
      }
      case SPACE_IMAGE: {
        SpaceImage *sima = (SpaceImage *)sl;

        sima->image = newlibadr_real_us(fd, parent_id->lib, sima->image);
        sima->mask_info.mask = newlibadr_real_us(fd, parent_id->lib, sima->mask_info.mask);

        /* NOTE: pre-2.5, this was local data not lib data, but now we need this as lib data
         * so fingers crossed this works fine!
         */
        sima->gpd = newlibadr_us(fd, parent_id->lib, sima->gpd);
        break;
      }
      case SPACE_SEQ: {
        SpaceSeq *sseq = (SpaceSeq *)sl;

        /* NOTE: pre-2.5, this was local data not lib data, but now we need this as lib data
         * so fingers crossed this works fine!
         */
        sseq->gpd = newlibadr_us(fd, parent_id->lib, sseq->gpd);
        break;
      }
      case SPACE_NLA: {
        SpaceNla *snla = (SpaceNla *)sl;
        bDopeSheet *ads = snla->ads;

        if (ads) {
          ads->source = newlibadr(fd, parent_id->lib, ads->source);
          ads->filter_grp = newlibadr(fd, parent_id->lib, ads->filter_grp);
        }
        break;
      }
      case SPACE_TEXT: {
        SpaceText *st = (SpaceText *)sl;

        st->text = newlibadr(fd, parent_id->lib, st->text);
        break;
      }
      case SPACE_SCRIPT: {
        SpaceScript *scpt = (SpaceScript *)sl;
        /*scpt->script = NULL; - 2.45 set to null, better re-run the script */
        if (scpt->script) {
          scpt->script = newlibadr(fd, parent_id->lib, scpt->script);
          if (scpt->script) {
            SCRIPT_SET_NULL(scpt->script);
          }
        }
        break;
      }
      case SPACE_OUTLINER: {
        SpaceOutliner *so = (SpaceOutliner *)sl;
        so->search_tse.id = newlibadr(fd, NULL, so->search_tse.id);

        if (so->treestore) {
          TreeStoreElem *tselem;
          BLI_mempool_iter iter;

          BLI_mempool_iternew(so->treestore, &iter);
          while ((tselem = BLI_mempool_iterstep(&iter))) {
            tselem->id = newlibadr(fd, NULL, tselem->id);
          }
          if (so->treehash) {
            /* rebuild hash table, because it depends on ids too */
            so->storeflag |= SO_TREESTORE_REBUILD;
          }
        }
        break;
      }
      case SPACE_NODE: {
        SpaceNode *snode = (SpaceNode *)sl;
        bNodeTreePath *path, *path_next;
        bNodeTree *ntree;

        /* node tree can be stored locally in id too, link this first */
        snode->id = newlibadr(fd, parent_id->lib, snode->id);
        snode->from = newlibadr(fd, parent_id->lib, snode->from);

        ntree = snode->id ? ntreeFromID(snode->id) : NULL;
        snode->nodetree = ntree ? ntree : newlibadr_us(fd, parent_id->lib, snode->nodetree);

        for (path = snode->treepath.first; path; path = path->next) {
          if (path == snode->treepath.first) {
            /* first nodetree in path is same as snode->nodetree */
            path->nodetree = snode->nodetree;
          }
          else {
            path->nodetree = newlibadr_us(fd, parent_id->lib, path->nodetree);
          }

          if (!path->nodetree) {
            break;
          }
        }

        /* remaining path entries are invalid, remove */
        for (; path; path = path_next) {
          path_next = path->next;

          BLI_remlink(&snode->treepath, path);
          MEM_freeN(path);
        }

        /* edittree is just the last in the path,
         * set this directly since the path may have been shortened above */
        if (snode->treepath.last) {
          path = snode->treepath.last;
          snode->edittree = path->nodetree;
        }
        else {
          snode->edittree = NULL;
        }
        break;
      }
      case SPACE_CLIP: {
        SpaceClip *sclip = (SpaceClip *)sl;
        sclip->clip = newlibadr_real_us(fd, parent_id->lib, sclip->clip);
        sclip->mask_info.mask = newlibadr_real_us(fd, parent_id->lib, sclip->mask_info.mask);
        break;
      }
      default:
        break;
    }
  }
}

/**
 * \return false on error.
 */
static bool direct_link_area_map(FileData *fd, ScrAreaMap *area_map)
{
  link_list(fd, &area_map->vertbase);
  link_list(fd, &area_map->edgebase);
  link_list(fd, &area_map->areabase);
  for (ScrArea *area = area_map->areabase.first; area; area = area->next) {
    direct_link_area(fd, area);
  }

  /* edges */
  for (ScrEdge *se = area_map->edgebase.first; se; se = se->next) {
    se->v1 = newdataadr(fd, se->v1);
    se->v2 = newdataadr(fd, se->v2);
    BKE_screen_sort_scrvert(&se->v1, &se->v2);

    if (se->v1 == NULL) {
      BLI_remlink(&area_map->edgebase, se);

      return false;
    }
  }

  return true;
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Read ID: Window Manager
 * \{ */

static void direct_link_windowmanager(FileData *fd, wmWindowManager *wm)
{
  wmWindow *win;

  id_us_ensure_real(&wm->id);
  link_list(fd, &wm->windows);

  for (win = wm->windows.first; win; win = win->next) {
    win->parent = newdataadr(fd, win->parent);

    WorkSpaceInstanceHook *hook = win->workspace_hook;
    win->workspace_hook = newdataadr(fd, hook);

    /* we need to restore a pointer to this later when reading workspaces,
     * so store in global oldnew-map. */
    oldnewmap_insert(fd->globmap, hook, win->workspace_hook, 0);

    direct_link_area_map(fd, &win->global_areas);

    win->ghostwin = NULL;
    win->gpuctx = NULL;
    win->eventstate = NULL;
    win->cursor_keymap_status = NULL;
    win->tweak = NULL;
#ifdef WIN32
    win->ime_data = NULL;
#endif

    BLI_listbase_clear(&win->queue);
    BLI_listbase_clear(&win->handlers);
    BLI_listbase_clear(&win->modalhandlers);
    BLI_listbase_clear(&win->gesture);

    win->active = 0;

    win->cursor = 0;
    win->lastcursor = 0;
    win->modalcursor = 0;
    win->grabcursor = 0;
    win->addmousemove = true;
    win->stereo3d_format = newdataadr(fd, win->stereo3d_format);

    /* multiview always fallback to anaglyph at file opening
     * otherwise quadbuffer saved files can break Blender */
    if (win->stereo3d_format) {
      win->stereo3d_format->display_mode = S3D_DISPLAY_ANAGLYPH;
    }
  }

  BLI_listbase_clear(&wm->timers);
  BLI_listbase_clear(&wm->operators);
  BLI_listbase_clear(&wm->paintcursors);
  BLI_listbase_clear(&wm->queue);
  BKE_reports_init(&wm->reports, RPT_STORE);

  BLI_listbase_clear(&wm->keyconfigs);
  wm->defaultconf = NULL;
  wm->addonconf = NULL;
  wm->userconf = NULL;
  wm->undo_stack = NULL;

  wm->message_bus = NULL;

  BLI_listbase_clear(&wm->jobs);
  BLI_listbase_clear(&wm->drags);

  wm->windrawable = NULL;
  wm->winactive = NULL;
  wm->initialized = 0;
  wm->op_undo_depth = 0;
  wm->is_interface_locked = 0;
}

static void lib_link_windowmanager(FileData *fd, Main *main)
{
  wmWindowManager *wm;
  wmWindow *win;

  for (wm = main->wm.first; wm; wm = wm->id.next) {
    if (wm->id.tag & LIB_TAG_NEED_LINK) {
      /* Note: WM IDProperties are never written to file, hence no need to read/link them here. */
      for (win = wm->windows.first; win; win = win->next) {
        if (win->workspace_hook) { /* NULL for old files */
          lib_link_workspace_instance_hook(fd, win->workspace_hook, &wm->id);
        }
        win->scene = newlibadr(fd, wm->id.lib, win->scene);
        /* deprecated, but needed for versioning (will be NULL'ed then) */
        win->screen = newlibadr(fd, NULL, win->screen);

        for (ScrArea *area = win->global_areas.areabase.first; area; area = area->next) {
          lib_link_area(fd, &wm->id, area);
        }
      }

      wm->id.tag &= ~LIB_TAG_NEED_LINK;
    }
  }
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Read ID: Screen
 * \{ */

/* note: file read without screens option G_FILE_NO_UI;
 * check lib pointers in call below */
static void lib_link_screen(FileData *fd, Main *main)
{
  for (bScreen *sc = main->screens.first; sc; sc = sc->id.next) {
    if (sc->id.tag & LIB_TAG_NEED_LINK) {
      IDP_LibLinkProperty(sc->id.properties, fd);

      /* deprecated, but needed for versioning (will be NULL'ed then) */
      sc->scene = newlibadr(fd, sc->id.lib, sc->scene);

      sc->animtimer = NULL; /* saved in rare cases */
      sc->tool_tip = NULL;
      sc->scrubbing = false;

      for (ScrArea *area = sc->areabase.first; area; area = area->next) {
        lib_link_area(fd, &sc->id, area);
      }
      sc->id.tag &= ~LIB_TAG_NEED_LINK;
    }
  }
}

/* how to handle user count on pointer restore */
typedef enum ePointerUserMode {
  USER_IGNORE = 0, /* ignore user count */
  USER_REAL = 1,   /* ensure at least one real user (fake user ignored) */
} ePointerUserMode;

static void restore_pointer_user(ID *id, ID *newid, ePointerUserMode user)
{
  BLI_assert(STREQ(newid->name + 2, id->name + 2));
  BLI_assert(newid->lib == id->lib);
  UNUSED_VARS_NDEBUG(id);

  if (user == USER_REAL) {
    id_us_ensure_real(newid);
  }
}

#ifndef USE_GHASH_RESTORE_POINTER
/**
 * A version of #restore_pointer_by_name that performs a full search (slow!).
 * Use only for limited lookups, when the overhead of
 * creating a #IDNameLib_Map for a single lookup isn't worthwhile.
 */
static void *restore_pointer_by_name_main(Main *mainp, ID *id, ePointerUserMode user)
{
  if (id) {
    ListBase *lb = which_libbase(mainp, GS(id->name));
    if (lb) { /* there's still risk of checking corrupt mem (freed Ids in oops) */
      ID *idn = lb->first;
      for (; idn; idn = idn->next) {
        if (STREQ(idn->name + 2, id->name + 2)) {
          if (idn->lib == id->lib) {
            restore_pointer_user(id, idn, user);
            break;
          }
        }
      }
      return idn;
    }
  }
  return NULL;
}
#endif

/**
 * Only for undo files, or to restore a screen after reading without UI...
 *
 * \param user:
 * - USER_IGNORE: no usercount change
 * - USER_REAL: ensure a real user (even if a fake one is set)
 * \param id_map: lookup table, use when performing many lookups.
 * this could be made an optional argument (falling back to a full lookup),
 * however at the moment it's always available.
 */
static void *restore_pointer_by_name(struct IDNameLib_Map *id_map, ID *id, ePointerUserMode user)
{
#ifdef USE_GHASH_RESTORE_POINTER
  if (id) {
    /* use fast lookup when available */
    ID *idn = BKE_main_idmap_lookup_id(id_map, id);
    if (idn) {
      restore_pointer_user(id, idn, user);
    }
    return idn;
  }
  return NULL;
#else
  Main *mainp = BKE_main_idmap_main_get(id_map);
  return restore_pointer_by_name_main(mainp, id, user);
#endif
}

static void lib_link_seq_clipboard_pt_restore(ID *id, struct IDNameLib_Map *id_map)
{
  if (id) {
    /* clipboard must ensure this */
    BLI_assert(id->newid != NULL);
    id->newid = restore_pointer_by_name(id_map, id->newid, USER_REAL);
  }
}
static int lib_link_seq_clipboard_cb(Sequence *seq, void *arg_pt)
{
  struct IDNameLib_Map *id_map = arg_pt;

  lib_link_seq_clipboard_pt_restore((ID *)seq->scene, id_map);
  lib_link_seq_clipboard_pt_restore((ID *)seq->scene_camera, id_map);
  lib_link_seq_clipboard_pt_restore((ID *)seq->clip, id_map);
  lib_link_seq_clipboard_pt_restore((ID *)seq->mask, id_map);
  lib_link_seq_clipboard_pt_restore((ID *)seq->sound, id_map);
  return 1;
}

static void lib_link_clipboard_restore(struct IDNameLib_Map *id_map)
{
  /* update IDs stored in sequencer clipboard */
  BKE_sequencer_base_recursive_apply(&seqbase_clipboard, lib_link_seq_clipboard_cb, id_map);
}

static void lib_link_window_scene_data_restore(wmWindow *win, Scene *scene, ViewLayer *view_layer)
{
  bScreen *screen = BKE_workspace_active_screen_get(win->workspace_hook);

  for (ScrArea *area = screen->areabase.first; area; area = area->next) {
    for (SpaceLink *sl = area->spacedata.first; sl; sl = sl->next) {
      if (sl->spacetype == SPACE_VIEW3D) {
        View3D *v3d = (View3D *)sl;

        if (v3d->camera == NULL || v3d->scenelock) {
          v3d->camera = scene->camera;
        }

        if (v3d->localvd) {
          Base *base = NULL;

          v3d->localvd->camera = scene->camera;

          /* Localview can become invalid during undo/redo steps,
           * so we exit it when no could be found. */
          for (base = view_layer->object_bases.first; base; base = base->next) {
            if (base->local_view_bits & v3d->local_view_uuid) {
              break;
            }
          }
          if (base == NULL) {
            MEM_freeN(v3d->localvd);
            v3d->localvd = NULL;
            v3d->local_view_uuid = 0;

            /* Regionbase storage is different depending if the space is active. */
            ListBase *regionbase = (sl == area->spacedata.first) ? &area->regionbase :
                                                                   &sl->regionbase;
            for (ARegion *ar = regionbase->first; ar; ar = ar->next) {
              if (ar->regiontype == RGN_TYPE_WINDOW) {
                RegionView3D *rv3d = ar->regiondata;
                if (rv3d->localvd) {
                  MEM_freeN(rv3d->localvd);
                  rv3d->localvd = NULL;
                }
              }
            }
          }
        }
      }
    }
  }
}

static void lib_link_workspace_layout_restore(struct IDNameLib_Map *id_map,
                                              Main *newmain,
                                              WorkSpaceLayout *layout)
{
  bScreen *screen = BKE_workspace_layout_screen_get(layout);

  /* avoid conflicts with 2.8x branch */
  {
    for (ScrArea *sa = screen->areabase.first; sa; sa = sa->next) {
      for (SpaceLink *sl = sa->spacedata.first; sl; sl = sl->next) {
        if (sl->spacetype == SPACE_VIEW3D) {
          View3D *v3d = (View3D *)sl;
          ARegion *ar;

          v3d->camera = restore_pointer_by_name(id_map, (ID *)v3d->camera, USER_REAL);
          v3d->ob_centre = restore_pointer_by_name(id_map, (ID *)v3d->ob_centre, USER_REAL);

          /* Free render engines for now. */
          ListBase *regionbase = (sl == sa->spacedata.first) ? &sa->regionbase : &sl->regionbase;
          for (ar = regionbase->first; ar; ar = ar->next) {
            if (ar->regiontype == RGN_TYPE_WINDOW) {
              RegionView3D *rv3d = ar->regiondata;
              if (rv3d && rv3d->render_engine) {
                RE_engine_free(rv3d->render_engine);
                rv3d->render_engine = NULL;
              }
            }
          }
        }
        else if (sl->spacetype == SPACE_GRAPH) {
          SpaceGraph *sipo = (SpaceGraph *)sl;
          bDopeSheet *ads = sipo->ads;

          if (ads) {
            ads->source = restore_pointer_by_name(id_map, (ID *)ads->source, USER_REAL);

            if (ads->filter_grp) {
              ads->filter_grp = restore_pointer_by_name(
                  id_map, (ID *)ads->filter_grp, USER_IGNORE);
            }
          }

          /* force recalc of list of channels (i.e. includes calculating F-Curve colors)
           * thus preventing the "black curves" problem post-undo
           */
          sipo->runtime.flag |= SIPO_RUNTIME_FLAG_NEED_CHAN_SYNC_COLOR;
        }
        else if (sl->spacetype == SPACE_PROPERTIES) {
          SpaceProperties *sbuts = (SpaceProperties *)sl;
          sbuts->pinid = restore_pointer_by_name(id_map, sbuts->pinid, USER_IGNORE);
          if (sbuts->pinid == NULL) {
            sbuts->flag &= ~SB_PIN_CONTEXT;
          }

          /* TODO: restore path pointers: T40046
           * (complicated because this contains data pointers too, not just ID)*/
          MEM_SAFE_FREE(sbuts->path);
        }
        else if (sl->spacetype == SPACE_FILE) {
          SpaceFile *sfile = (SpaceFile *)sl;
          sfile->op = NULL;
          sfile->previews_timer = NULL;
        }
        else if (sl->spacetype == SPACE_ACTION) {
          SpaceAction *saction = (SpaceAction *)sl;

          saction->action = restore_pointer_by_name(id_map, (ID *)saction->action, USER_REAL);
          saction->ads.source = restore_pointer_by_name(
              id_map, (ID *)saction->ads.source, USER_REAL);

          if (saction->ads.filter_grp) {
            saction->ads.filter_grp = restore_pointer_by_name(
                id_map, (ID *)saction->ads.filter_grp, USER_IGNORE);
          }

          /* force recalc of list of channels, potentially updating the active action
           * while we're at it (as it can only be updated that way) [#28962]
           */
          saction->runtime.flag |= SACTION_RUNTIME_FLAG_NEED_CHAN_SYNC;
        }
        else if (sl->spacetype == SPACE_IMAGE) {
          SpaceImage *sima = (SpaceImage *)sl;

          sima->image = restore_pointer_by_name(id_map, (ID *)sima->image, USER_REAL);

          /* this will be freed, not worth attempting to find same scene,
           * since it gets initialized later */
          sima->iuser.scene = NULL;

#if 0
          /* Those are allocated and freed by space code, no need to handle them here. */
          MEM_SAFE_FREE(sima->scopes.waveform_1);
          MEM_SAFE_FREE(sima->scopes.waveform_2);
          MEM_SAFE_FREE(sima->scopes.waveform_3);
          MEM_SAFE_FREE(sima->scopes.vecscope);
#endif
          sima->scopes.ok = 0;

          /* NOTE: pre-2.5, this was local data not lib data, but now we need this as lib data
           * so assume that here we're doing for undo only...
           */
          sima->gpd = restore_pointer_by_name(id_map, (ID *)sima->gpd, USER_REAL);
          sima->mask_info.mask = restore_pointer_by_name(
              id_map, (ID *)sima->mask_info.mask, USER_REAL);
        }
        else if (sl->spacetype == SPACE_SEQ) {
          SpaceSeq *sseq = (SpaceSeq *)sl;

          /* NOTE: pre-2.5, this was local data not lib data, but now we need this as lib data
           * so assume that here we're doing for undo only...
           */
          sseq->gpd = restore_pointer_by_name(id_map, (ID *)sseq->gpd, USER_REAL);
        }
        else if (sl->spacetype == SPACE_NLA) {
          SpaceNla *snla = (SpaceNla *)sl;
          bDopeSheet *ads = snla->ads;

          if (ads) {
            ads->source = restore_pointer_by_name(id_map, (ID *)ads->source, USER_REAL);

            if (ads->filter_grp) {
              ads->filter_grp = restore_pointer_by_name(
                  id_map, (ID *)ads->filter_grp, USER_IGNORE);
            }
          }
        }
        else if (sl->spacetype == SPACE_TEXT) {
          SpaceText *st = (SpaceText *)sl;

          st->text = restore_pointer_by_name(id_map, (ID *)st->text, USER_REAL);
          if (st->text == NULL) {
            st->text = newmain->texts.first;
          }
        }
        else if (sl->spacetype == SPACE_SCRIPT) {
          SpaceScript *scpt = (SpaceScript *)sl;

          scpt->script = restore_pointer_by_name(id_map, (ID *)scpt->script, USER_REAL);

          /*sc->script = NULL; - 2.45 set to null, better re-run the script */
          if (scpt->script) {
            SCRIPT_SET_NULL(scpt->script);
          }
        }
        else if (sl->spacetype == SPACE_OUTLINER) {
          SpaceOutliner *so = (SpaceOutliner *)sl;

          so->search_tse.id = restore_pointer_by_name(id_map, so->search_tse.id, USER_IGNORE);

          if (so->treestore) {
            TreeStoreElem *tselem;
            BLI_mempool_iter iter;

            BLI_mempool_iternew(so->treestore, &iter);
            while ((tselem = BLI_mempool_iterstep(&iter))) {
              /* Do not try to restore pointers to drivers/sequence/etc.,
               * can crash in undo case! */
              if (TSE_IS_REAL_ID(tselem)) {
                tselem->id = restore_pointer_by_name(id_map, tselem->id, USER_IGNORE);
              }
              else {
                tselem->id = NULL;
              }
            }
            if (so->treehash) {
              /* rebuild hash table, because it depends on ids too */
              so->storeflag |= SO_TREESTORE_REBUILD;
            }
          }
        }
        else if (sl->spacetype == SPACE_NODE) {
          SpaceNode *snode = (SpaceNode *)sl;
          bNodeTreePath *path, *path_next;
          bNodeTree *ntree;

          /* node tree can be stored locally in id too, link this first */
          snode->id = restore_pointer_by_name(id_map, snode->id, USER_REAL);
          snode->from = restore_pointer_by_name(id_map, snode->from, USER_IGNORE);

          ntree = snode->id ? ntreeFromID(snode->id) : NULL;
          snode->nodetree = ntree ?
                                ntree :
                                restore_pointer_by_name(id_map, (ID *)snode->nodetree, USER_REAL);

          for (path = snode->treepath.first; path; path = path->next) {
            if (path == snode->treepath.first) {
              /* first nodetree in path is same as snode->nodetree */
              path->nodetree = snode->nodetree;
            }
            else {
              path->nodetree = restore_pointer_by_name(id_map, (ID *)path->nodetree, USER_REAL);
            }

            if (!path->nodetree) {
              break;
            }
          }

          /* remaining path entries are invalid, remove */
          for (; path; path = path_next) {
            path_next = path->next;

            BLI_remlink(&snode->treepath, path);
            MEM_freeN(path);
          }

          /* edittree is just the last in the path,
           * set this directly since the path may have been shortened above */
          if (snode->treepath.last) {
            path = snode->treepath.last;
            snode->edittree = path->nodetree;
          }
          else {
            snode->edittree = NULL;
          }
        }
        else if (sl->spacetype == SPACE_CLIP) {
          SpaceClip *sclip = (SpaceClip *)sl;

          sclip->clip = restore_pointer_by_name(id_map, (ID *)sclip->clip, USER_REAL);
          sclip->mask_info.mask = restore_pointer_by_name(
              id_map, (ID *)sclip->mask_info.mask, USER_REAL);

          sclip->scopes.ok = 0;
        }
      }
    }
  }
}

/**
 * Used to link a file (without UI) to the current UI.
 * Note that it assumes the old pointers in UI are still valid, so old Main is not freed.
 */
void blo_lib_link_restore(Main *oldmain,
                          Main *newmain,
                          wmWindowManager *curwm,
                          Scene *curscene,
                          ViewLayer *cur_view_layer)
{
  struct IDNameLib_Map *id_map = BKE_main_idmap_create(newmain, true, oldmain);

  for (WorkSpace *workspace = newmain->workspaces.first; workspace;
       workspace = workspace->id.next) {
    ListBase *layouts = BKE_workspace_layouts_get(workspace);

    for (WorkSpaceLayout *layout = layouts->first; layout; layout = layout->next) {
      lib_link_workspace_layout_restore(id_map, newmain, layout);
    }
  }

  for (wmWindow *win = curwm->windows.first; win; win = win->next) {
    WorkSpace *workspace = BKE_workspace_active_get(win->workspace_hook);
    ID *workspace_id = (ID *)workspace;
    Scene *oldscene = win->scene;

    workspace = restore_pointer_by_name(id_map, workspace_id, USER_REAL);
    BKE_workspace_active_set(win->workspace_hook, workspace);
    win->scene = restore_pointer_by_name(id_map, (ID *)win->scene, USER_REAL);
    if (win->scene == NULL) {
      win->scene = curscene;
    }
    if (BKE_view_layer_find(win->scene, win->view_layer_name) == NULL) {
      STRNCPY(win->view_layer_name, cur_view_layer->name);
    }
    BKE_workspace_active_set(win->workspace_hook, workspace);

    /* keep cursor location through undo */
    memcpy(&win->scene->cursor, &oldscene->cursor, sizeof(win->scene->cursor));

    lib_link_window_scene_data_restore(win, win->scene, cur_view_layer);

    BLI_assert(win->screen == NULL);
  }

  /* update IDs stored in all possible clipboards */
  lib_link_clipboard_restore(id_map);

  BKE_main_idmap_destroy(id_map);
}

/* for the saved 2.50 files without regiondata */
/* and as patch for 2.48 and older */
void blo_do_versions_view3d_split_250(View3D *v3d, ListBase *regions)
{
  ARegion *ar;

  for (ar = regions->first; ar; ar = ar->next) {
    if (ar->regiontype == RGN_TYPE_WINDOW && ar->regiondata == NULL) {
      RegionView3D *rv3d;

      rv3d = ar->regiondata = MEM_callocN(sizeof(RegionView3D), "region v3d patch");
      rv3d->persp = (char)v3d->persp;
      rv3d->view = (char)v3d->view;
      rv3d->dist = v3d->dist;
      copy_v3_v3(rv3d->ofs, v3d->ofs);
      copy_qt_qt(rv3d->viewquat, v3d->viewquat);
    }
  }

  /* this was not initialized correct always */
  if (v3d->gridsubdiv == 0) {
    v3d->gridsubdiv = 10;
  }
}

static bool direct_link_screen(FileData *fd, bScreen *sc)
{
  bool wrong_id = false;

  sc->regionbase.first = sc->regionbase.last = NULL;
  sc->context = NULL;
  sc->active_region = NULL;

  sc->preview = direct_link_preview_image(fd, sc->preview);

  if (!direct_link_area_map(fd, AREAMAP_FROM_SCREEN(sc))) {
    printf("Error reading Screen %s... removing it.\n", sc->id.name + 2);
    wrong_id = true;
  }

  return wrong_id;
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Read ID: Library
 * \{ */

static void direct_link_library(FileData *fd, Library *lib, Main *main)
{
  Main *newmain;

  /* check if the library was already read */
  for (newmain = fd->mainlist->first; newmain; newmain = newmain->next) {
    if (newmain->curlib) {
      if (BLI_path_cmp(newmain->curlib->filepath, lib->filepath) == 0) {
        blo_reportf_wrap(fd->reports,
                         RPT_WARNING,
                         TIP_("Library '%s', '%s' had multiple instances, save and reload!"),
                         lib->name,
                         lib->filepath);

        change_link_placeholder_to_real_ID_pointer(fd->mainlist, fd, lib, newmain->curlib);
        /*              change_link_placeholder_to_real_ID_pointer_fd(fd, lib, newmain->curlib); */

        BLI_remlink(&main->libraries, lib);
        MEM_freeN(lib);

        /* Now, since Blender always expect **latest** Main pointer from fd->mainlist
         * to be the active library Main pointer,
         * where to add all non-library data-blocks found in file next, we have to switch that
         * 'dupli' found Main to latest position in the list!
         * Otherwise, you get weird disappearing linked data on a rather inconsistent basis.
         * See also T53977 for reproducible case. */
        BLI_remlink(fd->mainlist, newmain);
        BLI_addtail(fd->mainlist, newmain);

        return;
      }
    }
  }

  /* make sure we have full path in lib->filepath */
  BLI_strncpy(lib->filepath, lib->name, sizeof(lib->name));
  BLI_cleanup_path(fd->relabase, lib->filepath);

  //  printf("direct_link_library: name %s\n", lib->name);
  //  printf("direct_link_library: filepath %s\n", lib->filepath);

  lib->packedfile = direct_link_packedfile(fd, lib->packedfile);

  /* new main */
  newmain = BKE_main_new();
  BLI_addtail(fd->mainlist, newmain);
  newmain->curlib = lib;

  lib->parent = NULL;
}

static void lib_link_library(FileData *UNUSED(fd), Main *main)
{
  Library *lib;
  for (lib = main->libraries.first; lib; lib = lib->id.next) {
    id_us_ensure_real(&lib->id);
  }
}

/* Always call this once you have loaded new library data to set the relative paths correctly
 * in relation to the blend file. */
static void fix_relpaths_library(const char *basepath, Main *main)
{
  Library *lib;
  /* BLO_read_from_memory uses a blank filename */
  if (basepath == NULL || basepath[0] == '\0') {
    for (lib = main->libraries.first; lib; lib = lib->id.next) {
      /* when loading a linked lib into a file which has not been saved,
       * there is nothing we can be relative to, so instead we need to make
       * it absolute. This can happen when appending an object with a relative
       * link into an unsaved blend file. See [#27405].
       * The remap relative option will make it relative again on save - campbell */
      if (BLI_path_is_rel(lib->name)) {
        BLI_strncpy(lib->name, lib->filepath, sizeof(lib->name));
      }
    }
  }
  else {
    for (lib = main->libraries.first; lib; lib = lib->id.next) {
      /* Libraries store both relative and abs paths, recreate relative paths,
       * relative to the blend file since indirectly linked libs will be
       * relative to their direct linked library. */
      if (BLI_path_is_rel(lib->name)) { /* if this is relative to begin with? */
        BLI_strncpy(lib->name, lib->filepath, sizeof(lib->name));
        BLI_path_rel(lib->name, basepath);
      }
    }
  }
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Read ID: Light Probe
 * \{ */

static void lib_link_lightprobe(FileData *fd, Main *main)
{
  for (LightProbe *prb = main->lightprobes.first; prb; prb = prb->id.next) {
    if (prb->id.tag & LIB_TAG_NEED_LINK) {
      IDP_LibLinkProperty(prb->id.properties, fd);
      lib_link_animdata(fd, &prb->id, prb->adt);

      prb->visibility_grp = newlibadr(fd, prb->id.lib, prb->visibility_grp);

      prb->id.tag &= ~LIB_TAG_NEED_LINK;
    }
  }
}

static void direct_link_lightprobe(FileData *fd, LightProbe *prb)
{
  prb->adt = newdataadr(fd, prb->adt);
  direct_link_animdata(fd, prb->adt);
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Read ID: Speaker
 * \{ */

static void lib_link_speaker(FileData *fd, Main *main)
{
  for (Speaker *spk = main->speakers.first; spk; spk = spk->id.next) {
    if (spk->id.tag & LIB_TAG_NEED_LINK) {
      IDP_LibLinkProperty(spk->id.properties, fd);
      lib_link_animdata(fd, &spk->id, spk->adt);

      spk->sound = newlibadr_us(fd, spk->id.lib, spk->sound);

      spk->id.tag &= ~LIB_TAG_NEED_LINK;
    }
  }
}

static void direct_link_speaker(FileData *fd, Speaker *spk)
{
  spk->adt = newdataadr(fd, spk->adt);
  direct_link_animdata(fd, spk->adt);

#if 0
  spk->sound = newdataadr(fd, spk->sound);
  direct_link_sound(fd, spk->sound);
#endif
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Read ID: Sound
 * \{ */

static void direct_link_sound(FileData *fd, bSound *sound)
{
  sound->tags = 0;
  sound->handle = NULL;
  sound->playback_handle = NULL;

  /* versioning stuff, if there was a cache, then we enable caching: */
  if (sound->cache) {
    sound->flags |= SOUND_FLAGS_CACHING;
    sound->cache = NULL;
  }

  if (fd->soundmap) {
    sound->waveform = newsoundadr(fd, sound->waveform);
    sound->tags |= SOUND_TAGS_WAVEFORM_NO_RELOAD;
  }
  else {
    sound->waveform = NULL;
  }

  sound->spinlock = MEM_mallocN(sizeof(SpinLock), "sound_spinlock");
  BLI_spin_init(sound->spinlock);

  /* clear waveform loading flag */
  sound->tags &= ~SOUND_TAGS_WAVEFORM_LOADING;

  sound->packedfile = direct_link_packedfile(fd, sound->packedfile);
  sound->newpackedfile = direct_link_packedfile(fd, sound->newpackedfile);
}

static void lib_link_sound(FileData *fd, Main *main)
{
  for (bSound *sound = main->sounds.first; sound; sound = sound->id.next) {
    if (sound->id.tag & LIB_TAG_NEED_LINK) {
      IDP_LibLinkProperty(sound->id.properties, fd);

      sound->ipo = newlibadr_us(
          fd, sound->id.lib, sound->ipo);  // XXX deprecated - old animation system

      BKE_sound_reset_runtime(sound);

      sound->id.tag &= ~LIB_TAG_NEED_LINK;
    }
  }
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Read ID: Movie Clip
 * \{ */

static void direct_link_movieReconstruction(FileData *fd,
                                            MovieTrackingReconstruction *reconstruction)
{
  reconstruction->cameras = newdataadr(fd, reconstruction->cameras);
}

static void direct_link_movieTracks(FileData *fd, ListBase *tracksbase)
{
  MovieTrackingTrack *track;

  link_list(fd, tracksbase);

  for (track = tracksbase->first; track; track = track->next) {
    track->markers = newdataadr(fd, track->markers);
  }
}

static void direct_link_moviePlaneTracks(FileData *fd, ListBase *plane_tracks_base)
{
  MovieTrackingPlaneTrack *plane_track;

  link_list(fd, plane_tracks_base);

  for (plane_track = plane_tracks_base->first; plane_track; plane_track = plane_track->next) {
    int i;

    plane_track->point_tracks = newdataadr(fd, plane_track->point_tracks);
    test_pointer_array(fd, (void **)&plane_track->point_tracks);
    for (i = 0; i < plane_track->point_tracksnr; i++) {
      plane_track->point_tracks[i] = newdataadr(fd, plane_track->point_tracks[i]);
    }

    plane_track->markers = newdataadr(fd, plane_track->markers);
  }
}

static void direct_link_movieclip(FileData *fd, MovieClip *clip)
{
  MovieTracking *tracking = &clip->tracking;
  MovieTrackingObject *object;

  clip->adt = newdataadr(fd, clip->adt);

  if (fd->movieclipmap) {
    clip->cache = newmclipadr(fd, clip->cache);
  }
  else {
    clip->cache = NULL;
  }

  if (fd->movieclipmap) {
    clip->tracking.camera.intrinsics = newmclipadr(fd, clip->tracking.camera.intrinsics);
  }
  else {
    clip->tracking.camera.intrinsics = NULL;
  }

  direct_link_movieTracks(fd, &tracking->tracks);
  direct_link_moviePlaneTracks(fd, &tracking->plane_tracks);
  direct_link_movieReconstruction(fd, &tracking->reconstruction);

  clip->tracking.act_track = newdataadr(fd, clip->tracking.act_track);
  clip->tracking.act_plane_track = newdataadr(fd, clip->tracking.act_plane_track);

  clip->anim = NULL;
  clip->tracking_context = NULL;
  clip->tracking.stats = NULL;

  /* Needed for proper versioning, will be NULL for all newer files anyway. */
  clip->tracking.stabilization.rot_track = newdataadr(fd, clip->tracking.stabilization.rot_track);

  clip->tracking.dopesheet.ok = 0;
  BLI_listbase_clear(&clip->tracking.dopesheet.channels);
  BLI_listbase_clear(&clip->tracking.dopesheet.coverage_segments);

  link_list(fd, &tracking->objects);

  for (object = tracking->objects.first; object; object = object->next) {
    direct_link_movieTracks(fd, &object->tracks);
    direct_link_moviePlaneTracks(fd, &object->plane_tracks);
    direct_link_movieReconstruction(fd, &object->reconstruction);
  }
}

static void lib_link_movieTracks(FileData *fd, MovieClip *clip, ListBase *tracksbase)
{
  MovieTrackingTrack *track;

  for (track = tracksbase->first; track; track = track->next) {
    track->gpd = newlibadr_us(fd, clip->id.lib, track->gpd);
  }
}

static void lib_link_moviePlaneTracks(FileData *fd, MovieClip *clip, ListBase *tracksbase)
{
  MovieTrackingPlaneTrack *plane_track;

  for (plane_track = tracksbase->first; plane_track; plane_track = plane_track->next) {
    plane_track->image = newlibadr_us(fd, clip->id.lib, plane_track->image);
  }
}

static void lib_link_movieclip(FileData *fd, Main *main)
{
  for (MovieClip *clip = main->movieclips.first; clip; clip = clip->id.next) {
    if (clip->id.tag & LIB_TAG_NEED_LINK) {
      MovieTracking *tracking = &clip->tracking;

      IDP_LibLinkProperty(clip->id.properties, fd);
      lib_link_animdata(fd, &clip->id, clip->adt);

      clip->gpd = newlibadr_us(fd, clip->id.lib, clip->gpd);

      lib_link_movieTracks(fd, clip, &tracking->tracks);
      lib_link_moviePlaneTracks(fd, clip, &tracking->plane_tracks);

      for (MovieTrackingObject *object = tracking->objects.first; object; object = object->next) {
        lib_link_movieTracks(fd, clip, &object->tracks);
        lib_link_moviePlaneTracks(fd, clip, &object->plane_tracks);
      }

      clip->id.tag &= ~LIB_TAG_NEED_LINK;
    }
  }
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Read ID: Masks
 * \{ */

static void direct_link_mask(FileData *fd, Mask *mask)
{
  MaskLayer *masklay;

  mask->adt = newdataadr(fd, mask->adt);

  link_list(fd, &mask->masklayers);

  for (masklay = mask->masklayers.first; masklay; masklay = masklay->next) {
    MaskSpline *spline;
    MaskLayerShape *masklay_shape;

    /* can't use newdataadr since it's a pointer within an array */
    MaskSplinePoint *act_point_search = NULL;

    link_list(fd, &masklay->splines);

    for (spline = masklay->splines.first; spline; spline = spline->next) {
      MaskSplinePoint *points_old = spline->points;
      int i;

      spline->points = newdataadr(fd, spline->points);

      for (i = 0; i < spline->tot_point; i++) {
        MaskSplinePoint *point = &spline->points[i];

        if (point->tot_uw) {
          point->uw = newdataadr(fd, point->uw);
        }
      }

      /* detect active point */
      if ((act_point_search == NULL) && (masklay->act_point >= points_old) &&
          (masklay->act_point < points_old + spline->tot_point)) {
        act_point_search = &spline->points[masklay->act_point - points_old];
      }
    }

    link_list(fd, &masklay->splines_shapes);

    for (masklay_shape = masklay->splines_shapes.first; masklay_shape;
         masklay_shape = masklay_shape->next) {
      masklay_shape->data = newdataadr(fd, masklay_shape->data);

      if (masklay_shape->tot_vert) {
        if (fd->flags & FD_FLAGS_SWITCH_ENDIAN) {
          BLI_endian_switch_float_array(masklay_shape->data,
                                        masklay_shape->tot_vert * sizeof(float) *
                                            MASK_OBJECT_SHAPE_ELEM_SIZE);
        }
      }
    }

    masklay->act_spline = newdataadr(fd, masklay->act_spline);
    masklay->act_point = act_point_search;
  }
}

static void lib_link_mask_parent(FileData *fd, Mask *mask, MaskParent *parent)
{
  parent->id = newlibadr_us(fd, mask->id.lib, parent->id);
}

static void lib_link_mask(FileData *fd, Main *main)
{
  for (Mask *mask = main->masks.first; mask; mask = mask->id.next) {
    if (mask->id.tag & LIB_TAG_NEED_LINK) {
      IDP_LibLinkProperty(mask->id.properties, fd);
      lib_link_animdata(fd, &mask->id, mask->adt);

      for (MaskLayer *masklay = mask->masklayers.first; masklay; masklay = masklay->next) {
        MaskSpline *spline;

        spline = masklay->splines.first;
        while (spline) {
          int i;

          for (i = 0; i < spline->tot_point; i++) {
            MaskSplinePoint *point = &spline->points[i];

            lib_link_mask_parent(fd, mask, &point->parent);
          }

          lib_link_mask_parent(fd, mask, &spline->parent);

          spline = spline->next;
        }
      }

      mask->id.tag &= ~LIB_TAG_NEED_LINK;
    }
  }
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Read ID: Line Style
 * \{ */

static void lib_link_linestyle(FileData *fd, Main *main)
{
  for (FreestyleLineStyle *linestyle = main->linestyles.first; linestyle;
       linestyle = linestyle->id.next) {
    if (linestyle->id.tag & LIB_TAG_NEED_LINK) {
      LineStyleModifier *m;

      IDP_LibLinkProperty(linestyle->id.properties, fd);
      lib_link_animdata(fd, &linestyle->id, linestyle->adt);

      for (m = linestyle->color_modifiers.first; m; m = m->next) {
        switch (m->type) {
          case LS_MODIFIER_DISTANCE_FROM_OBJECT: {
            LineStyleColorModifier_DistanceFromObject *cm =
                (LineStyleColorModifier_DistanceFromObject *)m;
            cm->target = newlibadr(fd, linestyle->id.lib, cm->target);
            break;
          }
        }
      }
      for (m = linestyle->alpha_modifiers.first; m; m = m->next) {
        switch (m->type) {
          case LS_MODIFIER_DISTANCE_FROM_OBJECT: {
            LineStyleAlphaModifier_DistanceFromObject *am =
                (LineStyleAlphaModifier_DistanceFromObject *)m;
            am->target = newlibadr(fd, linestyle->id.lib, am->target);
            break;
          }
        }
      }
      for (m = linestyle->thickness_modifiers.first; m; m = m->next) {
        switch (m->type) {
          case LS_MODIFIER_DISTANCE_FROM_OBJECT: {
            LineStyleThicknessModifier_DistanceFromObject *tm =
                (LineStyleThicknessModifier_DistanceFromObject *)m;
            tm->target = newlibadr(fd, linestyle->id.lib, tm->target);
            break;
          }
        }
      }
      for (int a = 0; a < MAX_MTEX; a++) {
        MTex *mtex = linestyle->mtex[a];
        if (mtex) {
          mtex->tex = newlibadr_us(fd, linestyle->id.lib, mtex->tex);
          mtex->object = newlibadr(fd, linestyle->id.lib, mtex->object);
        }
      }
      if (linestyle->nodetree) {
        lib_link_ntree(fd, &linestyle->id, linestyle->nodetree);
        linestyle->nodetree->id.lib = linestyle->id.lib;
      }

      linestyle->id.tag &= ~LIB_TAG_NEED_LINK;
    }
  }
}

static void direct_link_linestyle_color_modifier(FileData *fd, LineStyleModifier *modifier)
{
  switch (modifier->type) {
    case LS_MODIFIER_ALONG_STROKE: {
      LineStyleColorModifier_AlongStroke *m = (LineStyleColorModifier_AlongStroke *)modifier;
      m->color_ramp = newdataadr(fd, m->color_ramp);
      break;
    }
    case LS_MODIFIER_DISTANCE_FROM_CAMERA: {
      LineStyleColorModifier_DistanceFromCamera *m = (LineStyleColorModifier_DistanceFromCamera *)
          modifier;
      m->color_ramp = newdataadr(fd, m->color_ramp);
      break;
    }
    case LS_MODIFIER_DISTANCE_FROM_OBJECT: {
      LineStyleColorModifier_DistanceFromObject *m = (LineStyleColorModifier_DistanceFromObject *)
          modifier;
      m->color_ramp = newdataadr(fd, m->color_ramp);
      break;
    }
    case LS_MODIFIER_MATERIAL: {
      LineStyleColorModifier_Material *m = (LineStyleColorModifier_Material *)modifier;
      m->color_ramp = newdataadr(fd, m->color_ramp);
      break;
    }
    case LS_MODIFIER_TANGENT: {
      LineStyleColorModifier_Tangent *m = (LineStyleColorModifier_Tangent *)modifier;
      m->color_ramp = newdataadr(fd, m->color_ramp);
      break;
    }
    case LS_MODIFIER_NOISE: {
      LineStyleColorModifier_Noise *m = (LineStyleColorModifier_Noise *)modifier;
      m->color_ramp = newdataadr(fd, m->color_ramp);
      break;
    }
    case LS_MODIFIER_CREASE_ANGLE: {
      LineStyleColorModifier_CreaseAngle *m = (LineStyleColorModifier_CreaseAngle *)modifier;
      m->color_ramp = newdataadr(fd, m->color_ramp);
      break;
    }
    case LS_MODIFIER_CURVATURE_3D: {
      LineStyleColorModifier_Curvature_3D *m = (LineStyleColorModifier_Curvature_3D *)modifier;
      m->color_ramp = newdataadr(fd, m->color_ramp);
      break;
    }
  }
}

static void direct_link_linestyle_alpha_modifier(FileData *fd, LineStyleModifier *modifier)
{
  switch (modifier->type) {
    case LS_MODIFIER_ALONG_STROKE: {
      LineStyleAlphaModifier_AlongStroke *m = (LineStyleAlphaModifier_AlongStroke *)modifier;
      m->curve = newdataadr(fd, m->curve);
      direct_link_curvemapping(fd, m->curve);
      break;
    }
    case LS_MODIFIER_DISTANCE_FROM_CAMERA: {
      LineStyleAlphaModifier_DistanceFromCamera *m = (LineStyleAlphaModifier_DistanceFromCamera *)
          modifier;
      m->curve = newdataadr(fd, m->curve);
      direct_link_curvemapping(fd, m->curve);
      break;
    }
    case LS_MODIFIER_DISTANCE_FROM_OBJECT: {
      LineStyleAlphaModifier_DistanceFromObject *m = (LineStyleAlphaModifier_DistanceFromObject *)
          modifier;
      m->curve = newdataadr(fd, m->curve);
      direct_link_curvemapping(fd, m->curve);
      break;
    }
    case LS_MODIFIER_MATERIAL: {
      LineStyleAlphaModifier_Material *m = (LineStyleAlphaModifier_Material *)modifier;
      m->curve = newdataadr(fd, m->curve);
      direct_link_curvemapping(fd, m->curve);
      break;
    }
    case LS_MODIFIER_TANGENT: {
      LineStyleAlphaModifier_Tangent *m = (LineStyleAlphaModifier_Tangent *)modifier;
      m->curve = newdataadr(fd, m->curve);
      direct_link_curvemapping(fd, m->curve);
      break;
    }
    case LS_MODIFIER_NOISE: {
      LineStyleAlphaModifier_Noise *m = (LineStyleAlphaModifier_Noise *)modifier;
      m->curve = newdataadr(fd, m->curve);
      direct_link_curvemapping(fd, m->curve);
      break;
    }
    case LS_MODIFIER_CREASE_ANGLE: {
      LineStyleAlphaModifier_CreaseAngle *m = (LineStyleAlphaModifier_CreaseAngle *)modifier;
      m->curve = newdataadr(fd, m->curve);
      direct_link_curvemapping(fd, m->curve);
      break;
    }
    case LS_MODIFIER_CURVATURE_3D: {
      LineStyleAlphaModifier_Curvature_3D *m = (LineStyleAlphaModifier_Curvature_3D *)modifier;
      m->curve = newdataadr(fd, m->curve);
      direct_link_curvemapping(fd, m->curve);
      break;
    }
  }
}

static void direct_link_linestyle_thickness_modifier(FileData *fd, LineStyleModifier *modifier)
{
  switch (modifier->type) {
    case LS_MODIFIER_ALONG_STROKE: {
      LineStyleThicknessModifier_AlongStroke *m = (LineStyleThicknessModifier_AlongStroke *)
          modifier;
      m->curve = newdataadr(fd, m->curve);
      direct_link_curvemapping(fd, m->curve);
      break;
    }
    case LS_MODIFIER_DISTANCE_FROM_CAMERA: {
      LineStyleThicknessModifier_DistanceFromCamera *m =
          (LineStyleThicknessModifier_DistanceFromCamera *)modifier;
      m->curve = newdataadr(fd, m->curve);
      direct_link_curvemapping(fd, m->curve);
      break;
    }
    case LS_MODIFIER_DISTANCE_FROM_OBJECT: {
      LineStyleThicknessModifier_DistanceFromObject *m =
          (LineStyleThicknessModifier_DistanceFromObject *)modifier;
      m->curve = newdataadr(fd, m->curve);
      direct_link_curvemapping(fd, m->curve);
      break;
    }
    case LS_MODIFIER_MATERIAL: {
      LineStyleThicknessModifier_Material *m = (LineStyleThicknessModifier_Material *)modifier;
      m->curve = newdataadr(fd, m->curve);
      direct_link_curvemapping(fd, m->curve);
      break;
    }
    case LS_MODIFIER_TANGENT: {
      LineStyleThicknessModifier_Tangent *m = (LineStyleThicknessModifier_Tangent *)modifier;
      m->curve = newdataadr(fd, m->curve);
      direct_link_curvemapping(fd, m->curve);
      break;
    }
    case LS_MODIFIER_CREASE_ANGLE: {
      LineStyleThicknessModifier_CreaseAngle *m = (LineStyleThicknessModifier_CreaseAngle *)
          modifier;
      m->curve = newdataadr(fd, m->curve);
      direct_link_curvemapping(fd, m->curve);
      break;
    }
    case LS_MODIFIER_CURVATURE_3D: {
      LineStyleThicknessModifier_Curvature_3D *m = (LineStyleThicknessModifier_Curvature_3D *)
          modifier;
      m->curve = newdataadr(fd, m->curve);
      direct_link_curvemapping(fd, m->curve);
      break;
    }
  }
}

static void direct_link_linestyle_geometry_modifier(FileData *UNUSED(fd),
                                                    LineStyleModifier *UNUSED(modifier))
{
}

static void direct_link_linestyle(FileData *fd, FreestyleLineStyle *linestyle)
{
  int a;
  LineStyleModifier *modifier;

  linestyle->adt = newdataadr(fd, linestyle->adt);
  direct_link_animdata(fd, linestyle->adt);
  link_list(fd, &linestyle->color_modifiers);
  for (modifier = linestyle->color_modifiers.first; modifier; modifier = modifier->next) {
    direct_link_linestyle_color_modifier(fd, modifier);
  }
  link_list(fd, &linestyle->alpha_modifiers);
  for (modifier = linestyle->alpha_modifiers.first; modifier; modifier = modifier->next) {
    direct_link_linestyle_alpha_modifier(fd, modifier);
  }
  link_list(fd, &linestyle->thickness_modifiers);
  for (modifier = linestyle->thickness_modifiers.first; modifier; modifier = modifier->next) {
    direct_link_linestyle_thickness_modifier(fd, modifier);
  }
  link_list(fd, &linestyle->geometry_modifiers);
  for (modifier = linestyle->geometry_modifiers.first; modifier; modifier = modifier->next) {
    direct_link_linestyle_geometry_modifier(fd, modifier);
  }
  for (a = 0; a < MAX_MTEX; a++) {
    linestyle->mtex[a] = newdataadr(fd, linestyle->mtex[a]);
  }
  linestyle->nodetree = newdataadr(fd, linestyle->nodetree);
  if (linestyle->nodetree) {
    direct_link_id(fd, &linestyle->nodetree->id);
    direct_link_nodetree(fd, linestyle->nodetree);
  }
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Read Library Data Block
 * \{ */

static ID *create_placeholder(Main *mainvar, const short idcode, const char *idname, const int tag)
{
  ListBase *lb = which_libbase(mainvar, idcode);
  ID *ph_id = BKE_libblock_alloc_notest(idcode);

  *((short *)ph_id->name) = idcode;
  BLI_strncpy(ph_id->name + 2, idname, sizeof(ph_id->name) - 2);
  BKE_libblock_init_empty(ph_id);
  ph_id->lib = mainvar->curlib;
  ph_id->tag = tag | LIB_TAG_MISSING;
  ph_id->us = ID_FAKE_USERS(ph_id);
  ph_id->icon_id = 0;

  BLI_addtail(lb, ph_id);
  id_sort_by_name(lb, ph_id);

  return ph_id;
}

static void placeholders_ensure_valid(Main *bmain)
{
  /* Placeholder ObData IDs won't have any material, we have to update their objects for that,
   * otherwise the inconsistency between both will lead to crashes (especially in Eevee?). */
  for (Object *ob = bmain->objects.first; ob != NULL; ob = ob->id.next) {
    ID *obdata = ob->data;
    if (obdata != NULL && obdata->tag & LIB_TAG_MISSING) {
      test_object_materials(bmain, ob, obdata);
    }
  }
}

static const char *dataname(short id_code)
{
  switch (id_code) {
    case ID_OB:
      return "Data from OB";
    case ID_ME:
      return "Data from ME";
    case ID_IP:
      return "Data from IP";
    case ID_SCE:
      return "Data from SCE";
    case ID_MA:
      return "Data from MA";
    case ID_TE:
      return "Data from TE";
    case ID_CU:
      return "Data from CU";
    case ID_GR:
      return "Data from GR";
    case ID_AR:
      return "Data from AR";
    case ID_AC:
      return "Data from AC";
    case ID_LI:
      return "Data from LI";
    case ID_MB:
      return "Data from MB";
    case ID_IM:
      return "Data from IM";
    case ID_LT:
      return "Data from LT";
    case ID_LA:
      return "Data from LA";
    case ID_CA:
      return "Data from CA";
    case ID_KE:
      return "Data from KE";
    case ID_WO:
      return "Data from WO";
    case ID_SCR:
      return "Data from SCR";
    case ID_VF:
      return "Data from VF";
    case ID_TXT:
      return "Data from TXT";
    case ID_SPK:
      return "Data from SPK";
    case ID_LP:
      return "Data from LP";
    case ID_SO:
      return "Data from SO";
    case ID_NT:
      return "Data from NT";
    case ID_BR:
      return "Data from BR";
    case ID_PA:
      return "Data from PA";
    case ID_PAL:
      return "Data from PAL";
    case ID_PC:
      return "Data from PCRV";
    case ID_GD:
      return "Data from GD";
    case ID_WM:
      return "Data from WM";
    case ID_MC:
      return "Data from MC";
    case ID_MSK:
      return "Data from MSK";
    case ID_LS:
      return "Data from LS";
    case ID_CF:
      return "Data from CF";
    case ID_WS:
      return "Data from WS";
  }
  return "Data from Lib Block";
}

static BHead *read_data_into_oldnewmap(FileData *fd, BHead *bhead, const char *allocname)
{
  bhead = blo_bhead_next(fd, bhead);

  while (bhead && bhead->code == DATA) {
    void *data;
#if 0
    /* XXX DUMB DEBUGGING OPTION TO GIVE NAMES for guarded malloc errors */
    short *sp = fd->filesdna->structs[bhead->SDNAnr];
    char *tmp = malloc(100);
    allocname = fd->filesdna->types[sp[0]];
    strcpy(tmp, allocname);
    data = read_struct(fd, bhead, tmp);
#else
    data = read_struct(fd, bhead, allocname);
#endif

    if (data) {
      oldnewmap_insert(fd->datamap, bhead->old, data, 0);
    }

    bhead = blo_bhead_next(fd, bhead);
  }

  return bhead;
}

static BHead *read_libblock(FileData *fd, Main *main, BHead *bhead, const int tag, ID **r_id)
{
  /* this routine reads a libblock and its direct data. Use link functions to connect it all
   */
  ID *id;
  ListBase *lb;
  const char *allocname;
  bool wrong_id = false;

  /* In undo case, most libs and linked data should be kept as is from previous state
   * (see BLO_read_from_memfile).
   * However, some needed by the snapshot being read may have been removed in previous one,
   * and would go missing.
   * This leads e.g. to disappearing objects in some undo/redo case, see T34446.
   * That means we have to carefully check whether current lib or
   * libdata already exits in old main, if it does we merely copy it over into new main area,
   * otherwise we have to do a full read of that bhead... */
  if (fd->memfile && ELEM(bhead->code, ID_LI, ID_LINK_PLACEHOLDER)) {
    const char *idname = blo_bhead_id_name(fd, bhead);

    DEBUG_PRINTF("Checking %s...\n", idname);

    if (bhead->code == ID_LI) {
      Main *libmain = fd->old_mainlist->first;
      /* Skip oldmain itself... */
      for (libmain = libmain->next; libmain; libmain = libmain->next) {
        DEBUG_PRINTF("... against %s: ", libmain->curlib ? libmain->curlib->id.name : "<NULL>");
        if (libmain->curlib && STREQ(idname, libmain->curlib->id.name)) {
          Main *oldmain = fd->old_mainlist->first;
          DEBUG_PRINTF("FOUND!\n");
          /* In case of a library, we need to re-add its main to fd->mainlist,
           * because if we have later a missing ID_LINK_PLACEHOLDER,
           * we need to get the correct lib it is linked to!
           * Order is crucial, we cannot bulk-add it in BLO_read_from_memfile()
           * like it used to be. */
          BLI_remlink(fd->old_mainlist, libmain);
          BLI_remlink_safe(&oldmain->libraries, libmain->curlib);
          BLI_addtail(fd->mainlist, libmain);
          BLI_addtail(&main->libraries, libmain->curlib);

          if (r_id) {
            *r_id = NULL; /* Just in case... */
          }
          return blo_bhead_next(fd, bhead);
        }
        DEBUG_PRINTF("nothing...\n");
      }
    }
    else {
      DEBUG_PRINTF("... in %s (%s): ",
                   main->curlib ? main->curlib->id.name : "<NULL>",
                   main->curlib ? main->curlib->name : "<NULL>");
      if ((id = BKE_libblock_find_name(main, GS(idname), idname + 2))) {
        DEBUG_PRINTF("FOUND!\n");
        /* Even though we found our linked ID,
         * there is no guarantee its address is still the same. */
        if (id != bhead->old) {
          oldnewmap_insert(fd->libmap, bhead->old, id, GS(id->name));
        }

        /* No need to do anything else for ID_LINK_PLACEHOLDER,
         * it's assumed already present in its lib's main. */
        if (r_id) {
          *r_id = NULL; /* Just in case... */
        }
        return blo_bhead_next(fd, bhead);
      }
      DEBUG_PRINTF("nothing...\n");
    }
  }

  /* read libblock */
  id = read_struct(fd, bhead, "lib block");

  if (id) {
    const short idcode = GS(id->name);
    /* do after read_struct, for dna reconstruct */
    lb = which_libbase(main, idcode);
    if (lb) {
      oldnewmap_insert(
          fd->libmap, bhead->old, id, bhead->code); /* for ID_LINK_PLACEHOLDER check */
      BLI_addtail(lb, id);
    }
    else {
      /* unknown ID type */
      printf("%s: unknown id code '%c%c'\n", __func__, (idcode & 0xff), (idcode >> 8));
      MEM_freeN(id);
      id = NULL;
    }
  }

  if (r_id) {
    *r_id = id;
  }
  if (!id) {
    return blo_bhead_next(fd, bhead);
  }

  id->lib = main->curlib;
  id->us = ID_FAKE_USERS(id);
  id->icon_id = 0;
  id->newid = NULL; /* Needed because .blend may have been saved with crap value here... */
  id->orig_id = NULL;

  /* NOTE: It is important to not clear the recalc flags for undo/redo.
   * Preserving recalc flags on redo/undo is the only way to make dependency graph detect
   * that animation is to be evaluated on undo/redo. If this is not enforced by the recalc
   * flags dependency graph does not do animation update to avoid loss of unkeyed changes.,
   * which conflicts with undo/redo of changes to animation data itself.
   *
   * But for regular file load we clear the flag, since the flags might have been changed sinde
   * the version the file has been saved with. */
  if (!fd->memfile) {
    id->recalc = 0;
  }

  /* this case cannot be direct_linked: it's just the ID part */
  if (bhead->code == ID_LINK_PLACEHOLDER) {
    /* That way, we know which data-lock needs do_versions (required currently for linking). */
    id->tag = tag | LIB_TAG_NEED_LINK | LIB_TAG_NEW;

    return blo_bhead_next(fd, bhead);
  }

  /* need a name for the mallocN, just for debugging and sane prints on leaks */
  allocname = dataname(GS(id->name));

  /* read all data into fd->datamap */
  bhead = read_data_into_oldnewmap(fd, bhead, allocname);

  /* init pointers direct data */
  direct_link_id(fd, id);

  /* That way, we know which data-lock needs do_versions (required currently for linking). */
  /* Note: doing this after driect_link_id(), which resets that field. */
  id->tag = tag | LIB_TAG_NEED_LINK | LIB_TAG_NEW;

  switch (GS(id->name)) {
    case ID_WM:
      direct_link_windowmanager(fd, (wmWindowManager *)id);
      break;
    case ID_SCR:
      wrong_id = direct_link_screen(fd, (bScreen *)id);
      break;
    case ID_SCE:
      direct_link_scene(fd, (Scene *)id);
      break;
    case ID_OB:
      direct_link_object(fd, (Object *)id);
      break;
    case ID_ME:
      direct_link_mesh(fd, (Mesh *)id);
      break;
    case ID_CU:
      direct_link_curve(fd, (Curve *)id);
      break;
    case ID_MB:
      direct_link_mball(fd, (MetaBall *)id);
      break;
    case ID_MA:
      direct_link_material(fd, (Material *)id);
      break;
    case ID_TE:
      direct_link_texture(fd, (Tex *)id);
      break;
    case ID_IM:
      direct_link_image(fd, (Image *)id);
      break;
    case ID_LA:
      direct_link_light(fd, (Light *)id);
      break;
    case ID_VF:
      direct_link_vfont(fd, (VFont *)id);
      break;
    case ID_TXT:
      direct_link_text(fd, (Text *)id);
      break;
    case ID_IP:
      direct_link_ipo(fd, (Ipo *)id);
      break;
    case ID_KE:
      direct_link_key(fd, (Key *)id);
      break;
    case ID_LT:
      direct_link_latt(fd, (Lattice *)id);
      break;
    case ID_WO:
      direct_link_world(fd, (World *)id);
      break;
    case ID_LI:
      direct_link_library(fd, (Library *)id, main);
      break;
    case ID_CA:
      direct_link_camera(fd, (Camera *)id);
      break;
    case ID_SPK:
      direct_link_speaker(fd, (Speaker *)id);
      break;
    case ID_SO:
      direct_link_sound(fd, (bSound *)id);
      break;
    case ID_LP:
      direct_link_lightprobe(fd, (LightProbe *)id);
      break;
    case ID_GR:
      direct_link_collection(fd, (Collection *)id);
      break;
    case ID_AR:
      direct_link_armature(fd, (bArmature *)id);
      break;
    case ID_AC:
      direct_link_action(fd, (bAction *)id);
      break;
    case ID_NT:
      direct_link_nodetree(fd, (bNodeTree *)id);
      break;
    case ID_BR:
      direct_link_brush(fd, (Brush *)id);
      break;
    case ID_PA:
      direct_link_particlesettings(fd, (ParticleSettings *)id);
      break;
    case ID_GD:
      direct_link_gpencil(fd, (bGPdata *)id);
      break;
    case ID_MC:
      direct_link_movieclip(fd, (MovieClip *)id);
      break;
    case ID_MSK:
      direct_link_mask(fd, (Mask *)id);
      break;
    case ID_LS:
      direct_link_linestyle(fd, (FreestyleLineStyle *)id);
      break;
    case ID_PAL:
      direct_link_palette(fd, (Palette *)id);
      break;
    case ID_PC:
      direct_link_paint_curve(fd, (PaintCurve *)id);
      break;
    case ID_CF:
      direct_link_cachefile(fd, (CacheFile *)id);
      break;
    case ID_WS:
      direct_link_workspace(fd, (WorkSpace *)id, main);
      break;
  }

  oldnewmap_free_unused(fd->datamap);
  oldnewmap_clear(fd->datamap);

  if (wrong_id) {
    BKE_id_free(main, id);
  }

  return (bhead);
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Read Global Data
 * \{ */

/* note, this has to be kept for reading older files... */
/* also version info is written here */
static BHead *read_global(BlendFileData *bfd, FileData *fd, BHead *bhead)
{
  FileGlobal *fg = read_struct(fd, bhead, "Global");

  /* copy to bfd handle */
  bfd->main->subversionfile = fg->subversion;
  bfd->main->minversionfile = fg->minversion;
  bfd->main->minsubversionfile = fg->minsubversion;
  bfd->main->build_commit_timestamp = fg->build_commit_timestamp;
  BLI_strncpy(bfd->main->build_hash, fg->build_hash, sizeof(bfd->main->build_hash));

  bfd->fileflags = fg->fileflags;
  bfd->globalf = fg->globalf;
  BLI_strncpy(bfd->filename, fg->filename, sizeof(bfd->filename));

  /* Error in 2.65 and older: main->name was not set if you save from startup
   * (not after loading file). */
  if (bfd->filename[0] == 0) {
    if (fd->fileversion < 265 || (fd->fileversion == 265 && fg->subversion < 1)) {
      if ((G.fileflags & G_FILE_RECOVER) == 0) {
        BLI_strncpy(bfd->filename, BKE_main_blendfile_path(bfd->main), sizeof(bfd->filename));
      }
    }

    /* early 2.50 version patch - filename not in FileGlobal struct at all */
    if (fd->fileversion <= 250) {
      BLI_strncpy(bfd->filename, BKE_main_blendfile_path(bfd->main), sizeof(bfd->filename));
    }
  }

  if (G.fileflags & G_FILE_RECOVER) {
    BLI_strncpy(fd->relabase, fg->filename, sizeof(fd->relabase));
  }

  bfd->curscreen = fg->curscreen;
  bfd->curscene = fg->curscene;
  bfd->cur_view_layer = fg->cur_view_layer;

  MEM_freeN(fg);

  fd->globalf = bfd->globalf;
  fd->fileflags = bfd->fileflags;

  return blo_bhead_next(fd, bhead);
}

/* note, this has to be kept for reading older files... */
static void link_global(FileData *fd, BlendFileData *bfd)
{
  bfd->cur_view_layer = newglobadr(fd, bfd->cur_view_layer);
  bfd->curscreen = newlibadr(fd, NULL, bfd->curscreen);
  bfd->curscene = newlibadr(fd, NULL, bfd->curscene);
  // this happens in files older than 2.35
  if (bfd->curscene == NULL) {
    if (bfd->curscreen) {
      bfd->curscene = bfd->curscreen->scene;
    }
  }
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Versioning
 * \{ */

/* initialize userdef with non-UI dependency stuff */
/* other initializers (such as theme color defaults) go to resources.c */
static void do_versions_userdef(FileData *fd, BlendFileData *bfd)
{
  Main *bmain = bfd->main;
  UserDef *user = bfd->user;

  if (user == NULL) {
    return;
  }

  if (MAIN_VERSION_OLDER(bmain, 266, 4)) {
    bTheme *btheme;

    /* Themes for Node and Sequence editor were not using grid color,
     * but back. we copy this over then. */
    for (btheme = user->themes.first; btheme; btheme = btheme->next) {
      copy_v4_v4_uchar(btheme->space_node.grid, btheme->space_node.back);
      copy_v4_v4_uchar(btheme->space_sequencer.grid, btheme->space_sequencer.back);
    }
  }

  if (!DNA_struct_elem_find(fd->filesdna, "UserDef", "WalkNavigation", "walk_navigation")) {
    user->walk_navigation.mouse_speed = 1.0f;
    user->walk_navigation.walk_speed = 2.5f; /* m/s */
    user->walk_navigation.walk_speed_factor = 5.0f;
    user->walk_navigation.view_height = 1.6f;   /* m */
    user->walk_navigation.jump_height = 0.4f;   /* m */
    user->walk_navigation.teleport_time = 0.2f; /* s */
  }

  /* grease pencil multisamples */
  if (!DNA_struct_elem_find(fd->filesdna, "UserDef", "short", "gpencil_multisamples")) {
    user->gpencil_multisamples = 4;
  }

  /* tablet pressure threshold */
  if (!DNA_struct_elem_find(fd->filesdna, "UserDef", "float", "pressure_threshold_max")) {
    user->pressure_threshold_max = 1.0f;
  }
}

static void do_versions(FileData *fd, Library *lib, Main *main)
{
  /* WATCH IT!!!: pointers from libdata have not been converted */

  if (G.debug & G_DEBUG) {
    char build_commit_datetime[32];
    time_t temp_time = main->build_commit_timestamp;
    struct tm *tm = (temp_time) ? gmtime(&temp_time) : NULL;
    if (LIKELY(tm)) {
      strftime(build_commit_datetime, sizeof(build_commit_datetime), "%Y-%m-%d %H:%M", tm);
    }
    else {
      BLI_strncpy(build_commit_datetime, "unknown", sizeof(build_commit_datetime));
    }

    printf("read file %s\n  Version %d sub %d date %s hash %s\n",
           fd->relabase,
           main->versionfile,
           main->subversionfile,
           build_commit_datetime,
           main->build_hash);
  }

  blo_do_versions_pre250(fd, lib, main);
  blo_do_versions_250(fd, lib, main);
  blo_do_versions_260(fd, lib, main);
  blo_do_versions_270(fd, lib, main);
  blo_do_versions_280(fd, lib, main);
  blo_do_versions_cycles(fd, lib, main);

  /* WATCH IT!!!: pointers from libdata have not been converted yet here! */
  /* WATCH IT 2!: Userdef struct init see do_versions_userdef() above! */

  /* don't forget to set version number in BKE_blender_version.h! */
}

static void do_versions_after_linking(Main *main)
{
  //  printf("%s for %s (%s), %d.%d\n", __func__, main->curlib ? main->curlib->name : main->name,
  //         main->curlib ? "LIB" : "MAIN", main->versionfile, main->subversionfile);

  do_versions_after_linking_250(main);
  do_versions_after_linking_260(main);
  do_versions_after_linking_270(main);
  do_versions_after_linking_280(main);
  do_versions_after_linking_cycles(main);
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Read Library Data Block (all)
 * \{ */

static void lib_link_all(FileData *fd, Main *main)
{
  lib_link_id(fd, main);

  /* No load UI for undo memfiles */
  if (fd->memfile == NULL) {
    lib_link_windowmanager(fd, main);
  }
  /* DO NOT skip screens here,
   * 3D viewport may contains pointers to other ID data (like bgpic)! See T41411. */
  lib_link_screen(fd, main);
  lib_link_scene(fd, main);
  lib_link_object(fd, main);
  lib_link_mesh(fd, main);
  lib_link_curve(fd, main);
  lib_link_mball(fd, main);
  lib_link_material(fd, main);
  lib_link_texture(fd, main);
  lib_link_image(fd, main);
  lib_link_ipo(
      fd, main); /* XXX deprecated... still needs to be maintained for version patches still */
  lib_link_key(fd, main);
  lib_link_world(fd, main);
  lib_link_light(fd, main);
  lib_link_latt(fd, main);
  lib_link_text(fd, main);
  lib_link_camera(fd, main);
  lib_link_speaker(fd, main);
  lib_link_lightprobe(fd, main);
  lib_link_sound(fd, main);
  lib_link_collection(fd, main);
  lib_link_armature(fd, main);
  lib_link_action(fd, main);
  lib_link_vfont(fd, main);
  lib_link_nodetree(fd,
                    main); /* has to be done after scene/materials, this will verify group nodes */
  lib_link_palette(fd, main);
  lib_link_brush(fd, main);
  lib_link_paint_curve(fd, main);
  lib_link_particlesettings(fd, main);
  lib_link_movieclip(fd, main);
  lib_link_mask(fd, main);
  lib_link_linestyle(fd, main);
  lib_link_gpencil(fd, main);
  lib_link_cachefiles(fd, main);
  lib_link_workspaces(fd, main);

  lib_link_library(fd, main); /* only init users */

  /* We could integrate that to mesh/curve/lattice lib_link, but this is really cheap process,
   * so simpler to just use it directly in this single call. */
  BLO_main_validate_shapekeys(main, NULL);

  if (fd->memfile != NULL) {
    /* When doing redo, we perform a tremendous amount of esoteric magic tricks to avoid having to
     * re-read all library data-blocks.
     * Unfortunately, that means that we do not clear Collections' parents lists, which then get
     * improperly extended in some cases by lib_link_scene() and lib_link_collection() calls above
     * (when one local collection is parent of linked ones).
     * I do not really see a way to address that issue, besides brute force call below which
     * invalidates and re-creates all parenting relationships between collections. Yet another
     * example of why it is such a bad idea to keep that kind of double-linked relationships info
     * 'permanently' in our data structures... */
    BKE_main_collections_parent_relations_rebuild(main);
  }
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Read User Preferences
 * \{ */

static void direct_link_keymapitem(FileData *fd, wmKeyMapItem *kmi)
{
  kmi->properties = newdataadr(fd, kmi->properties);
  IDP_DirectLinkGroup_OrFree(&kmi->properties, (fd->flags & FD_FLAGS_SWITCH_ENDIAN), fd);
  kmi->ptr = NULL;
  kmi->flag &= ~KMI_UPDATE;
}

static BHead *read_userdef(BlendFileData *bfd, FileData *fd, BHead *bhead)
{
  UserDef *user;
  wmKeyMap *keymap;
  wmKeyMapItem *kmi;
  wmKeyMapDiffItem *kmdi;
  bAddon *addon;

  bfd->user = user = read_struct(fd, bhead, "user def");

  /* User struct has separate do-version handling */
  user->versionfile = bfd->main->versionfile;
  user->subversionfile = bfd->main->subversionfile;

  /* read all data into fd->datamap */
  bhead = read_data_into_oldnewmap(fd, bhead, "user def");

  link_list(fd, &user->themes);
  link_list(fd, &user->user_keymaps);
  link_list(fd, &user->user_keyconfig_prefs);
  link_list(fd, &user->user_menus);
  link_list(fd, &user->addons);
  link_list(fd, &user->autoexec_paths);

  for (keymap = user->user_keymaps.first; keymap; keymap = keymap->next) {
    keymap->modal_items = NULL;
    keymap->poll = NULL;
    keymap->flag &= ~KEYMAP_UPDATE;

    link_list(fd, &keymap->diff_items);
    link_list(fd, &keymap->items);

    for (kmdi = keymap->diff_items.first; kmdi; kmdi = kmdi->next) {
      kmdi->remove_item = newdataadr(fd, kmdi->remove_item);
      kmdi->add_item = newdataadr(fd, kmdi->add_item);

      if (kmdi->remove_item) {
        direct_link_keymapitem(fd, kmdi->remove_item);
      }
      if (kmdi->add_item) {
        direct_link_keymapitem(fd, kmdi->add_item);
      }
    }

    for (kmi = keymap->items.first; kmi; kmi = kmi->next) {
      direct_link_keymapitem(fd, kmi);
    }
  }

  for (wmKeyConfigPref *kpt = user->user_keyconfig_prefs.first; kpt; kpt = kpt->next) {
    kpt->prop = newdataadr(fd, kpt->prop);
    IDP_DirectLinkGroup_OrFree(&kpt->prop, (fd->flags & FD_FLAGS_SWITCH_ENDIAN), fd);
  }

  for (bUserMenu *um = user->user_menus.first; um; um = um->next) {
    link_list(fd, &um->items);
    for (bUserMenuItem *umi = um->items.first; umi; umi = umi->next) {
      if (umi->type == USER_MENU_TYPE_OPERATOR) {
        bUserMenuItem_Op *umi_op = (bUserMenuItem_Op *)umi;
        umi_op->prop = newdataadr(fd, umi_op->prop);
        IDP_DirectLinkGroup_OrFree(&umi_op->prop, (fd->flags & FD_FLAGS_SWITCH_ENDIAN), fd);
      }
    }
  }

  for (addon = user->addons.first; addon; addon = addon->next) {
    addon->prop = newdataadr(fd, addon->prop);
    IDP_DirectLinkGroup_OrFree(&addon->prop, (fd->flags & FD_FLAGS_SWITCH_ENDIAN), fd);
  }

  // XXX
  user->uifonts.first = user->uifonts.last = NULL;

  link_list(fd, &user->uistyles);

  /* Don't read the active app template, use the default one. */
  user->app_template[0] = '\0';

  /* Clear runtime data. */
  user->runtime.is_dirty = false;
  user->edit_studio_light = 0;

  /* free fd->datamap again */
  oldnewmap_free_unused(fd->datamap);
  oldnewmap_clear(fd->datamap);

  return bhead;
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Read File (Internal)
 * \{ */

BlendFileData *blo_read_file_internal(FileData *fd, const char *filepath)
{
  BHead *bhead = blo_bhead_first(fd);
  BlendFileData *bfd;
  ListBase mainlist = {NULL, NULL};

  bfd = MEM_callocN(sizeof(BlendFileData), "blendfiledata");

  bfd->main = BKE_main_new();
  bfd->main->versionfile = fd->fileversion;

  bfd->type = BLENFILETYPE_BLEND;

  if ((fd->skip_flags & BLO_READ_SKIP_DATA) == 0) {
    BLI_addtail(&mainlist, bfd->main);
    fd->mainlist = &mainlist;
    BLI_strncpy(bfd->main->name, filepath, sizeof(bfd->main->name));
  }

  if (G.background) {
    /* We only read & store .blend thumbnail in background mode
     * (because we cannot re-generate it, no OpenGL available).
     */
    const int *data = read_file_thumbnail(fd);

    if (data) {
      const int width = data[0];
      const int height = data[1];
      if (BLEN_THUMB_MEMSIZE_IS_VALID(width, height)) {
        const size_t sz = BLEN_THUMB_MEMSIZE(width, height);
        bfd->main->blen_thumb = MEM_mallocN(sz, __func__);

        BLI_assert((sz - sizeof(*bfd->main->blen_thumb)) ==
                   (BLEN_THUMB_MEMSIZE_FILE(width, height) - (sizeof(*data) * 2)));
        bfd->main->blen_thumb->width = width;
        bfd->main->blen_thumb->height = height;
        memcpy(bfd->main->blen_thumb->rect, &data[2], sz - sizeof(*bfd->main->blen_thumb));
      }
    }
  }

  while (bhead) {
    switch (bhead->code) {
      case DATA:
      case DNA1:
      case TEST: /* used as preview since 2.5x */
      case REND:
        bhead = blo_bhead_next(fd, bhead);
        break;
      case GLOB:
        bhead = read_global(bfd, fd, bhead);
        break;
      case USER:
        if (fd->skip_flags & BLO_READ_SKIP_USERDEF) {
          bhead = blo_bhead_next(fd, bhead);
        }
        else {
          bhead = read_userdef(bfd, fd, bhead);
        }
        break;
      case ENDB:
        bhead = NULL;
        break;

      case ID_LINK_PLACEHOLDER:
        if (fd->skip_flags & BLO_READ_SKIP_DATA) {
          bhead = blo_bhead_next(fd, bhead);
        }
        else {
          /* Add link placeholder to the main of the library it belongs to.
           * The library is the most recently loaded ID_LI block, according
           * to the file format definition. So we can use the entry at the
           * end of mainlist, added in direct_link_library. */
          Main *libmain = mainlist.last;
          bhead = read_libblock(
              fd, libmain, bhead, LIB_TAG_ID_LINK_PLACEHOLDER | LIB_TAG_EXTERN, NULL);
        }
        break;
      /* in 2.50+ files, the file identifier for screens is patched, forward compatibility */
      case ID_SCRN:
        bhead->code = ID_SCR;
        /* pass on to default */
        ATTR_FALLTHROUGH;
      default:
        if (fd->skip_flags & BLO_READ_SKIP_DATA) {
          bhead = blo_bhead_next(fd, bhead);
        }
        else {
          bhead = read_libblock(fd, bfd->main, bhead, LIB_TAG_LOCAL, NULL);
        }
    }
  }

  /* do before read_libraries, but skip undo case */
  if (fd->memfile == NULL) {
    if ((fd->skip_flags & BLO_READ_SKIP_DATA) == 0) {
      do_versions(fd, NULL, bfd->main);
    }

    if ((fd->skip_flags & BLO_READ_SKIP_USERDEF) == 0) {
      do_versions_userdef(fd, bfd);
    }
  }

  if ((fd->skip_flags & BLO_READ_SKIP_DATA) == 0) {
    read_libraries(fd, &mainlist);

    blo_join_main(&mainlist);

    lib_link_all(fd, bfd->main);

    /* Skip in undo case. */
    if (fd->memfile == NULL) {
      /* Yep, second splitting... but this is a very cheap operation, so no big deal. */
      blo_split_main(&mainlist, bfd->main);
      for (Main *mainvar = mainlist.first; mainvar; mainvar = mainvar->next) {
        BLI_assert(mainvar->versionfile != 0);
        do_versions_after_linking(mainvar);
      }
      blo_join_main(&mainlist);

      /* After all data has been read and versioned, uses LIB_TAG_NEW. */
      ntreeUpdateAllNew(bfd->main);
    }

    placeholders_ensure_valid(bfd->main);

    BKE_main_id_tag_all(bfd->main, LIB_TAG_NEW, false);

    /* Now that all our data-blocks are loaded,
     * we can re-generate overrides from their references. */
    if (fd->memfile == NULL) {
      /* Do not apply in undo case! */
      BKE_main_override_library_update(bfd->main);
    }

    BKE_collections_after_lib_link(bfd->main);

    /* Make all relative paths, relative to the open blend file. */
    fix_relpaths_library(fd->relabase, bfd->main);

    link_global(fd, bfd); /* as last */
  }

  fd->mainlist = NULL; /* Safety, this is local variable, shall not be used afterward. */

  return bfd;
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Library Linking
 *
 * Also used for append.
 * \{ */

struct BHeadSort {
  BHead *bhead;
  const void *old;
};

static int verg_bheadsort(const void *v1, const void *v2)
{
  const struct BHeadSort *x1 = v1, *x2 = v2;

  if (x1->old > x2->old) {
    return 1;
  }
  else if (x1->old < x2->old) {
    return -1;
  }
  return 0;
}

static void sort_bhead_old_map(FileData *fd)
{
  BHead *bhead;
  struct BHeadSort *bhs;
  int tot = 0;

  for (bhead = blo_bhead_first(fd); bhead; bhead = blo_bhead_next(fd, bhead)) {
    tot++;
  }

  fd->tot_bheadmap = tot;
  if (tot == 0) {
    return;
  }

  bhs = fd->bheadmap = MEM_malloc_arrayN(tot, sizeof(struct BHeadSort), "BHeadSort");

  for (bhead = blo_bhead_first(fd); bhead; bhead = blo_bhead_next(fd, bhead), bhs++) {
    bhs->bhead = bhead;
    bhs->old = bhead->old;
  }

  qsort(fd->bheadmap, tot, sizeof(struct BHeadSort), verg_bheadsort);
}

static BHead *find_previous_lib(FileData *fd, BHead *bhead)
{
  /* Skip library data-blocks in undo, see comment in read_libblock. */
  if (fd->memfile) {
    return NULL;
  }

  for (; bhead; bhead = blo_bhead_prev(fd, bhead)) {
    if (bhead->code == ID_LI) {
      break;
    }
  }

  return bhead;
}

static BHead *find_bhead(FileData *fd, void *old)
{
#if 0
  BHead *bhead;
#endif
  struct BHeadSort *bhs, bhs_s;

  if (!old) {
    return NULL;
  }

  if (fd->bheadmap == NULL) {
    sort_bhead_old_map(fd);
  }

  bhs_s.old = old;
  bhs = bsearch(&bhs_s, fd->bheadmap, fd->tot_bheadmap, sizeof(struct BHeadSort), verg_bheadsort);

  if (bhs) {
    return bhs->bhead;
  }

#if 0
  for (bhead = blo_bhead_first(fd); bhead; bhead = blo_bhead_next(fd, bhead)) {
    if (bhead->old == old) {
      return bhead;
    }
  }
#endif

  return NULL;
}

static BHead *find_bhead_from_code_name(FileData *fd, const short idcode, const char *name)
{
#ifdef USE_GHASH_BHEAD

  char idname_full[MAX_ID_NAME];

  *((short *)idname_full) = idcode;
  BLI_strncpy(idname_full + 2, name, sizeof(idname_full) - 2);

  return BLI_ghash_lookup(fd->bhead_idname_hash, idname_full);

#else
  BHead *bhead;

  for (bhead = blo_bhead_first(fd); bhead; bhead = blo_bhead_next(fd, bhead)) {
    if (bhead->code == idcode) {
      const char *idname_test = blo_bhead_id_name(fd, bhead);
      if (STREQ(idname_test + 2, name)) {
        return bhead;
      }
    }
    else if (bhead->code == ENDB) {
      break;
    }
  }

  return NULL;
#endif
}

static BHead *find_bhead_from_idname(FileData *fd, const char *idname)
{
#ifdef USE_GHASH_BHEAD
  return BLI_ghash_lookup(fd->bhead_idname_hash, idname);
#else
  return find_bhead_from_code_name(fd, GS(idname), idname + 2);
#endif
}

static ID *is_yet_read(FileData *fd, Main *mainvar, BHead *bhead)
{
  const char *idname = blo_bhead_id_name(fd, bhead);
  /* which_libbase can be NULL, intentionally not using idname+2 */
  return BLI_findstring(which_libbase(mainvar, GS(idname)), idname, offsetof(ID, name));
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Library Linking (expand pointers)
 * \{ */

static void expand_doit_library(void *fdhandle, Main *mainvar, void *old)
{
  FileData *fd = fdhandle;

  BHead *bhead = find_bhead(fd, old);
  if (bhead == NULL) {
    return;
  }

  if (bhead->code == ID_LINK_PLACEHOLDER) {
    /* Placeholder link to data-lock in another library. */
    BHead *bheadlib = find_previous_lib(fd, bhead);
    if (bheadlib == NULL) {
      return;
    }

    Library *lib = read_struct(fd, bheadlib, "Library");
    Main *libmain = blo_find_main(fd, lib->name, fd->relabase);

    if (libmain->curlib == NULL) {
      const char *idname = blo_bhead_id_name(fd, bhead);

      blo_reportf_wrap(fd->reports,
                       RPT_WARNING,
                       TIP_("LIB: Data refers to main .blend file: '%s' from %s"),
                       idname,
                       mainvar->curlib->filepath);
      return;
    }

    ID *id = is_yet_read(fd, libmain, bhead);

    if (id == NULL) {
      /* ID has not been read yet, add placeholder to the main of the
       * library it belongs to, so that it will be read later. */
      read_libblock(fd, libmain, bhead, LIB_TAG_ID_LINK_PLACEHOLDER | LIB_TAG_INDIRECT, NULL);
      // commented because this can print way too much
      // if (G.debug & G_DEBUG) printf("expand_doit: other lib %s\n", lib->name);

      /* for outliner dependency only */
      libmain->curlib->parent = mainvar->curlib;
    }
    else {
      /* "id" is either a placeholder or real ID that is already in the
       * main of the library (A) it belongs to. However it might have been
       * put there by another library (C) which only updated its own
       * fd->libmap. In that case we also need to update the fd->libmap
       * of the current library (B) so we can find it for lookups.
       *
       * An example of such a setup is:
       * (A) tree.blend: contains Tree object.
       * (B) forest.blend: contains Forest collection linking in Tree from tree.blend.
       * (C) shot.blend: links in both Tree from tree.blend and Forest from forest.blend.
       */
      oldnewmap_insert(fd->libmap, bhead->old, id, bhead->code);

      /* If "id" is a real data-lock and not a placeholder, we need to
       * update fd->libmap to replace ID_LINK_PLACEHOLDER with the real
       * ID_* code.
       *
       * When the real ID is read this replacement happens for all
       * libraries read so far, but not for libraries that have not been
       * read yet at that point. */
      change_link_placeholder_to_real_ID_pointer_fd(fd, bhead->old, id);

      /* Commented because this can print way too much. */
#if 0
      if (G.debug & G_DEBUG) {
        printf("expand_doit: already linked: %s lib: %s\n", id->name, lib->name);
      }
#endif
    }

    MEM_freeN(lib);
  }
  else {
    /* Data-block in same library. */
    /* In 2.50+ file identifier for screens is patched, forward compatibility. */
    if (bhead->code == ID_SCRN) {
      bhead->code = ID_SCR;
    }

    ID *id = is_yet_read(fd, mainvar, bhead);
    if (id == NULL) {
      read_libblock(fd, mainvar, bhead, LIB_TAG_NEED_EXPAND | LIB_TAG_INDIRECT, NULL);
    }
    else {
      /* this is actually only needed on UI call? when ID was already read before,
       * and another append happens which invokes same ID...
       * in that case the lookup table needs this entry */
      oldnewmap_insert(fd->libmap, bhead->old, id, bhead->code);
      // commented because this can print way too much
      // if (G.debug & G_DEBUG) printf("expand: already read %s\n", id->name);
    }
  }
}

static BLOExpandDoitCallback expand_doit;

// XXX deprecated - old animation system
static void expand_ipo(FileData *fd, Main *mainvar, Ipo *ipo)
{
  IpoCurve *icu;
  for (icu = ipo->curve.first; icu; icu = icu->next) {
    if (icu->driver) {
      expand_doit(fd, mainvar, icu->driver->ob);
    }
  }
}

// XXX deprecated - old animation system
static void expand_constraint_channels(FileData *fd, Main *mainvar, ListBase *chanbase)
{
  bConstraintChannel *chan;
  for (chan = chanbase->first; chan; chan = chan->next) {
    expand_doit(fd, mainvar, chan->ipo);
  }
}

static void expand_id(FileData *fd, Main *mainvar, ID *id)
{
  if (id->override_library) {
    expand_doit(fd, mainvar, id->override_library->reference);
    expand_doit(fd, mainvar, id->override_library->storage);
  }
}

static void expand_idprops(FileData *fd, Main *mainvar, IDProperty *prop)
{
  if (!prop) {
    return;
  }

  switch (prop->type) {
    case IDP_ID:
      expand_doit(fd, mainvar, IDP_Id(prop));
      break;
    case IDP_IDPARRAY: {
      IDProperty *idp_array = IDP_IDPArray(prop);
      for (int i = 0; i < prop->len; i++) {
        expand_idprops(fd, mainvar, &idp_array[i]);
      }
      break;
    }
    case IDP_GROUP:
      for (IDProperty *loop = prop->data.group.first; loop; loop = loop->next) {
        expand_idprops(fd, mainvar, loop);
      }
      break;
  }
}

static void expand_fmodifiers(FileData *fd, Main *mainvar, ListBase *list)
{
  FModifier *fcm;

  for (fcm = list->first; fcm; fcm = fcm->next) {
    /* library data for specific F-Modifier types */
    switch (fcm->type) {
      case FMODIFIER_TYPE_PYTHON: {
        FMod_Python *data = (FMod_Python *)fcm->data;

        expand_doit(fd, mainvar, data->script);

        break;
      }
    }
  }
}

static void expand_fcurves(FileData *fd, Main *mainvar, ListBase *list)
{
  FCurve *fcu;

  for (fcu = list->first; fcu; fcu = fcu->next) {
    /* Driver targets if there is a driver */
    if (fcu->driver) {
      ChannelDriver *driver = fcu->driver;
      DriverVar *dvar;

      for (dvar = driver->variables.first; dvar; dvar = dvar->next) {
        DRIVER_TARGETS_LOOPER_BEGIN (dvar) {
          // TODO: only expand those that are going to get used?
          expand_doit(fd, mainvar, dtar->id);
        }
        DRIVER_TARGETS_LOOPER_END;
      }
    }

    /* F-Curve Modifiers */
    expand_fmodifiers(fd, mainvar, &fcu->modifiers);
  }
}

static void expand_action(FileData *fd, Main *mainvar, bAction *act)
{
  bActionChannel *chan;

  // XXX deprecated - old animation system --------------
  for (chan = act->chanbase.first; chan; chan = chan->next) {
    expand_doit(fd, mainvar, chan->ipo);
    expand_constraint_channels(fd, mainvar, &chan->constraintChannels);
  }
  // ---------------------------------------------------

  /* F-Curves in Action */
  expand_fcurves(fd, mainvar, &act->curves);

  for (TimeMarker *marker = act->markers.first; marker; marker = marker->next) {
    if (marker->camera) {
      expand_doit(fd, mainvar, marker->camera);
    }
  }
}

static void expand_keyingsets(FileData *fd, Main *mainvar, ListBase *list)
{
  KeyingSet *ks;
  KS_Path *ksp;

  /* expand the ID-pointers in KeyingSets's paths */
  for (ks = list->first; ks; ks = ks->next) {
    for (ksp = ks->paths.first; ksp; ksp = ksp->next) {
      expand_doit(fd, mainvar, ksp->id);
    }
  }
}

static void expand_animdata_nlastrips(FileData *fd, Main *mainvar, ListBase *list)
{
  NlaStrip *strip;

  for (strip = list->first; strip; strip = strip->next) {
    /* check child strips */
    expand_animdata_nlastrips(fd, mainvar, &strip->strips);

    /* check F-Curves */
    expand_fcurves(fd, mainvar, &strip->fcurves);

    /* check F-Modifiers */
    expand_fmodifiers(fd, mainvar, &strip->modifiers);

    /* relink referenced action */
    expand_doit(fd, mainvar, strip->act);
  }
}

static void expand_animdata(FileData *fd, Main *mainvar, AnimData *adt)
{
  NlaTrack *nlt;

  /* own action */
  expand_doit(fd, mainvar, adt->action);
  expand_doit(fd, mainvar, adt->tmpact);

  /* drivers - assume that these F-Curves have driver data to be in this list... */
  expand_fcurves(fd, mainvar, &adt->drivers);

  /* nla-data - referenced actions */
  for (nlt = adt->nla_tracks.first; nlt; nlt = nlt->next) {
    expand_animdata_nlastrips(fd, mainvar, &nlt->strips);
  }
}

static void expand_particlesettings(FileData *fd, Main *mainvar, ParticleSettings *part)
{
  int a;

  expand_doit(fd, mainvar, part->instance_object);
  expand_doit(fd, mainvar, part->instance_collection);
  expand_doit(fd, mainvar, part->eff_group);
  expand_doit(fd, mainvar, part->bb_ob);
  expand_doit(fd, mainvar, part->collision_group);

  if (part->adt) {
    expand_animdata(fd, mainvar, part->adt);
  }

  for (a = 0; a < MAX_MTEX; a++) {
    if (part->mtex[a]) {
      expand_doit(fd, mainvar, part->mtex[a]->tex);
      expand_doit(fd, mainvar, part->mtex[a]->object);
    }
  }

  if (part->effector_weights) {
    expand_doit(fd, mainvar, part->effector_weights->group);
  }

  if (part->pd) {
    expand_doit(fd, mainvar, part->pd->tex);
    expand_doit(fd, mainvar, part->pd->f_source);
  }
  if (part->pd2) {
    expand_doit(fd, mainvar, part->pd2->tex);
    expand_doit(fd, mainvar, part->pd2->f_source);
  }

  if (part->boids) {
    BoidState *state;
    BoidRule *rule;

    for (state = part->boids->states.first; state; state = state->next) {
      for (rule = state->rules.first; rule; rule = rule->next) {
        if (rule->type == eBoidRuleType_Avoid) {
          BoidRuleGoalAvoid *gabr = (BoidRuleGoalAvoid *)rule;
          expand_doit(fd, mainvar, gabr->ob);
        }
        else if (rule->type == eBoidRuleType_FollowLeader) {
          BoidRuleFollowLeader *flbr = (BoidRuleFollowLeader *)rule;
          expand_doit(fd, mainvar, flbr->ob);
        }
      }
    }
  }

  for (ParticleDupliWeight *dw = part->instance_weights.first; dw; dw = dw->next) {
    expand_doit(fd, mainvar, dw->ob);
  }
}

static void expand_collection(FileData *fd, Main *mainvar, Collection *collection)
{
  for (CollectionObject *cob = collection->gobject.first; cob; cob = cob->next) {
    expand_doit(fd, mainvar, cob->ob);
  }

  for (CollectionChild *child = collection->children.first; child; child = child->next) {
    expand_doit(fd, mainvar, child->collection);
  }

#ifdef USE_COLLECTION_COMPAT_28
  if (collection->collection != NULL) {
    expand_scene_collection(fd, mainvar, collection->collection);
  }
#endif
}

static void expand_key(FileData *fd, Main *mainvar, Key *key)
{
  expand_doit(fd, mainvar, key->ipo);  // XXX deprecated - old animation system

  if (key->adt) {
    expand_animdata(fd, mainvar, key->adt);
  }
}

static void expand_nodetree(FileData *fd, Main *mainvar, bNodeTree *ntree)
{
  bNode *node;
  bNodeSocket *sock;

  if (ntree->adt) {
    expand_animdata(fd, mainvar, ntree->adt);
  }

  if (ntree->gpd) {
    expand_doit(fd, mainvar, ntree->gpd);
  }

  for (node = ntree->nodes.first; node; node = node->next) {
    if (node->id && node->type != CMP_NODE_R_LAYERS) {
      expand_doit(fd, mainvar, node->id);
    }

    expand_idprops(fd, mainvar, node->prop);

    for (sock = node->inputs.first; sock; sock = sock->next) {
      expand_idprops(fd, mainvar, sock->prop);
    }
    for (sock = node->outputs.first; sock; sock = sock->next) {
      expand_idprops(fd, mainvar, sock->prop);
    }
  }

  for (sock = ntree->inputs.first; sock; sock = sock->next) {
    expand_idprops(fd, mainvar, sock->prop);
  }
  for (sock = ntree->outputs.first; sock; sock = sock->next) {
    expand_idprops(fd, mainvar, sock->prop);
  }
}

static void expand_texture(FileData *fd, Main *mainvar, Tex *tex)
{
  expand_doit(fd, mainvar, tex->ima);
  expand_doit(fd, mainvar, tex->ipo);  // XXX deprecated - old animation system

  if (tex->adt) {
    expand_animdata(fd, mainvar, tex->adt);
  }

  if (tex->nodetree) {
    expand_nodetree(fd, mainvar, tex->nodetree);
  }
}

static void expand_brush(FileData *fd, Main *mainvar, Brush *brush)
{
  expand_doit(fd, mainvar, brush->mtex.tex);
  expand_doit(fd, mainvar, brush->mask_mtex.tex);
  expand_doit(fd, mainvar, brush->clone.image);
  expand_doit(fd, mainvar, brush->paint_curve);
  if (brush->gpencil_settings != NULL) {
    expand_doit(fd, mainvar, brush->gpencil_settings->material);
  }
}

static void expand_material(FileData *fd, Main *mainvar, Material *ma)
{
  expand_doit(fd, mainvar, ma->ipo);  // XXX deprecated - old animation system

  if (ma->adt) {
    expand_animdata(fd, mainvar, ma->adt);
  }

  if (ma->nodetree) {
    expand_nodetree(fd, mainvar, ma->nodetree);
  }

  if (ma->gp_style) {
    MaterialGPencilStyle *gp_style = ma->gp_style;
    expand_doit(fd, mainvar, gp_style->sima);
    expand_doit(fd, mainvar, gp_style->ima);
  }
}

static void expand_light(FileData *fd, Main *mainvar, Light *la)
{
  expand_doit(fd, mainvar, la->ipo);  // XXX deprecated - old animation system

  if (la->adt) {
    expand_animdata(fd, mainvar, la->adt);
  }

  if (la->nodetree) {
    expand_nodetree(fd, mainvar, la->nodetree);
  }
}

static void expand_lattice(FileData *fd, Main *mainvar, Lattice *lt)
{
  expand_doit(fd, mainvar, lt->ipo);  // XXX deprecated - old animation system
  expand_doit(fd, mainvar, lt->key);

  if (lt->adt) {
    expand_animdata(fd, mainvar, lt->adt);
  }
}

static void expand_world(FileData *fd, Main *mainvar, World *wrld)
{
  expand_doit(fd, mainvar, wrld->ipo);  // XXX deprecated - old animation system

  if (wrld->adt) {
    expand_animdata(fd, mainvar, wrld->adt);
  }

  if (wrld->nodetree) {
    expand_nodetree(fd, mainvar, wrld->nodetree);
  }
}

static void expand_mball(FileData *fd, Main *mainvar, MetaBall *mb)
{
  int a;

  for (a = 0; a < mb->totcol; a++) {
    expand_doit(fd, mainvar, mb->mat[a]);
  }

  if (mb->adt) {
    expand_animdata(fd, mainvar, mb->adt);
  }
}

static void expand_curve(FileData *fd, Main *mainvar, Curve *cu)
{
  int a;

  for (a = 0; a < cu->totcol; a++) {
    expand_doit(fd, mainvar, cu->mat[a]);
  }

  expand_doit(fd, mainvar, cu->vfont);
  expand_doit(fd, mainvar, cu->vfontb);
  expand_doit(fd, mainvar, cu->vfonti);
  expand_doit(fd, mainvar, cu->vfontbi);
  expand_doit(fd, mainvar, cu->key);
  expand_doit(fd, mainvar, cu->ipo);  // XXX deprecated - old animation system
  expand_doit(fd, mainvar, cu->bevobj);
  expand_doit(fd, mainvar, cu->taperobj);
  expand_doit(fd, mainvar, cu->textoncurve);

  if (cu->adt) {
    expand_animdata(fd, mainvar, cu->adt);
  }
}

static void expand_mesh(FileData *fd, Main *mainvar, Mesh *me)
{
  int a;

  if (me->adt) {
    expand_animdata(fd, mainvar, me->adt);
  }

  for (a = 0; a < me->totcol; a++) {
    expand_doit(fd, mainvar, me->mat[a]);
  }

  expand_doit(fd, mainvar, me->key);
  expand_doit(fd, mainvar, me->texcomesh);
}

/* temp struct used to transport needed info to expand_constraint_cb() */
typedef struct tConstraintExpandData {
  FileData *fd;
  Main *mainvar;
} tConstraintExpandData;
/* callback function used to expand constraint ID-links */
static void expand_constraint_cb(bConstraint *UNUSED(con),
                                 ID **idpoin,
                                 bool UNUSED(is_reference),
                                 void *userdata)
{
  tConstraintExpandData *ced = (tConstraintExpandData *)userdata;
  expand_doit(ced->fd, ced->mainvar, *idpoin);
}

static void expand_constraints(FileData *fd, Main *mainvar, ListBase *lb)
{
  tConstraintExpandData ced;
  bConstraint *curcon;

  /* relink all ID-blocks used by the constraints */
  ced.fd = fd;
  ced.mainvar = mainvar;

  BKE_constraints_id_loop(lb, expand_constraint_cb, &ced);

  /* deprecated manual expansion stuff */
  for (curcon = lb->first; curcon; curcon = curcon->next) {
    if (curcon->ipo) {
      expand_doit(fd, mainvar, curcon->ipo);  // XXX deprecated - old animation system
    }
  }
}

static void expand_pose(FileData *fd, Main *mainvar, bPose *pose)
{
  bPoseChannel *chan;

  if (!pose) {
    return;
  }

  for (chan = pose->chanbase.first; chan; chan = chan->next) {
    expand_constraints(fd, mainvar, &chan->constraints);
    expand_idprops(fd, mainvar, chan->prop);
    expand_doit(fd, mainvar, chan->custom);
  }
}

static void expand_bones(FileData *fd, Main *mainvar, Bone *bone)
{
  expand_idprops(fd, mainvar, bone->prop);

  for (Bone *curBone = bone->childbase.first; curBone; curBone = curBone->next) {
    expand_bones(fd, mainvar, curBone);
  }
}

static void expand_armature(FileData *fd, Main *mainvar, bArmature *arm)
{
  if (arm->adt) {
    expand_animdata(fd, mainvar, arm->adt);
  }

  for (Bone *curBone = arm->bonebase.first; curBone; curBone = curBone->next) {
    expand_bones(fd, mainvar, curBone);
  }
}

static void expand_object_expandModifiers(void *userData,
                                          Object *UNUSED(ob),
                                          ID **idpoin,
                                          int UNUSED(cb_flag))
{
  struct {
    FileData *fd;
    Main *mainvar;
  } *data = userData;

  FileData *fd = data->fd;
  Main *mainvar = data->mainvar;

  expand_doit(fd, mainvar, *idpoin);
}

static void expand_object(FileData *fd, Main *mainvar, Object *ob)
{
  ParticleSystem *psys;
  bActionStrip *strip;
  PartEff *paf;
  int a;

  expand_doit(fd, mainvar, ob->data);

  /* expand_object_expandModifier() */
  if (ob->modifiers.first) {
    struct {
      FileData *fd;
      Main *mainvar;
    } data;
    data.fd = fd;
    data.mainvar = mainvar;

    modifiers_foreachIDLink(ob, expand_object_expandModifiers, (void *)&data);
  }

  /* expand_object_expandModifier() */
  if (ob->greasepencil_modifiers.first) {
    struct {
      FileData *fd;
      Main *mainvar;
    } data;
    data.fd = fd;
    data.mainvar = mainvar;

    BKE_gpencil_modifiers_foreachIDLink(ob, expand_object_expandModifiers, (void *)&data);
  }

  /* expand_object_expandShaderFx() */
  if (ob->shader_fx.first) {
    struct {
      FileData *fd;
      Main *mainvar;
    } data;
    data.fd = fd;
    data.mainvar = mainvar;

    BKE_shaderfx_foreachIDLink(ob, expand_object_expandModifiers, (void *)&data);
  }

  expand_pose(fd, mainvar, ob->pose);
  expand_doit(fd, mainvar, ob->poselib);
  expand_constraints(fd, mainvar, &ob->constraints);

  expand_doit(fd, mainvar, ob->gpd);

  // XXX deprecated - old animation system (for version patching only)
  expand_doit(fd, mainvar, ob->ipo);
  expand_doit(fd, mainvar, ob->action);

  expand_constraint_channels(fd, mainvar, &ob->constraintChannels);

  for (strip = ob->nlastrips.first; strip; strip = strip->next) {
    expand_doit(fd, mainvar, strip->object);
    expand_doit(fd, mainvar, strip->act);
    expand_doit(fd, mainvar, strip->ipo);
  }
  // XXX deprecated - old animation system (for version patching only)

  if (ob->adt) {
    expand_animdata(fd, mainvar, ob->adt);
  }

  for (a = 0; a < ob->totcol; a++) {
    expand_doit(fd, mainvar, ob->mat[a]);
  }

  paf = blo_do_version_give_parteff_245(ob);
  if (paf && paf->group) {
    expand_doit(fd, mainvar, paf->group);
  }

  if (ob->instance_collection) {
    expand_doit(fd, mainvar, ob->instance_collection);
  }

  if (ob->proxy) {
    expand_doit(fd, mainvar, ob->proxy);
  }
  if (ob->proxy_group) {
    expand_doit(fd, mainvar, ob->proxy_group);
  }

  for (psys = ob->particlesystem.first; psys; psys = psys->next) {
    expand_doit(fd, mainvar, psys->part);
  }

  if (ob->pd) {
    expand_doit(fd, mainvar, ob->pd->tex);
    expand_doit(fd, mainvar, ob->pd->f_source);
  }

  if (ob->soft) {
    expand_doit(fd, mainvar, ob->soft->collision_group);

    if (ob->soft->effector_weights) {
      expand_doit(fd, mainvar, ob->soft->effector_weights->group);
    }
  }

  if (ob->rigidbody_constraint) {
    expand_doit(fd, mainvar, ob->rigidbody_constraint->ob1);
    expand_doit(fd, mainvar, ob->rigidbody_constraint->ob2);
  }

  if (ob->currentlod) {
    LodLevel *level;
    for (level = ob->lodlevels.first; level; level = level->next) {
      expand_doit(fd, mainvar, level->source);
    }
  }
}

#ifdef USE_COLLECTION_COMPAT_28
static void expand_scene_collection(FileData *fd, Main *mainvar, SceneCollection *sc)
{
  for (LinkData *link = sc->objects.first; link; link = link->next) {
    expand_doit(fd, mainvar, link->data);
  }

  for (SceneCollection *nsc = sc->scene_collections.first; nsc; nsc = nsc->next) {
    expand_scene_collection(fd, mainvar, nsc);
  }
}
#endif

static void expand_scene(FileData *fd, Main *mainvar, Scene *sce)
{
  SceneRenderLayer *srl;
  FreestyleModuleConfig *module;
  FreestyleLineSet *lineset;

  for (Base *base_legacy = sce->base.first; base_legacy; base_legacy = base_legacy->next) {
    expand_doit(fd, mainvar, base_legacy->object);
  }
  expand_doit(fd, mainvar, sce->camera);
  expand_doit(fd, mainvar, sce->world);

  if (sce->adt) {
    expand_animdata(fd, mainvar, sce->adt);
  }
  expand_keyingsets(fd, mainvar, &sce->keyingsets);

  if (sce->set) {
    expand_doit(fd, mainvar, sce->set);
  }

  if (sce->nodetree) {
    expand_nodetree(fd, mainvar, sce->nodetree);
  }

  for (srl = sce->r.layers.first; srl; srl = srl->next) {
    expand_doit(fd, mainvar, srl->mat_override);
    for (module = srl->freestyleConfig.modules.first; module; module = module->next) {
      if (module->script) {
        expand_doit(fd, mainvar, module->script);
      }
    }
    for (lineset = srl->freestyleConfig.linesets.first; lineset; lineset = lineset->next) {
      if (lineset->group) {
        expand_doit(fd, mainvar, lineset->group);
      }
      expand_doit(fd, mainvar, lineset->linestyle);
    }
  }

  for (ViewLayer *view_layer = sce->view_layers.first; view_layer; view_layer = view_layer->next) {
    expand_idprops(fd, mainvar, view_layer->id_properties);

    for (module = view_layer->freestyle_config.modules.first; module; module = module->next) {
      if (module->script) {
        expand_doit(fd, mainvar, module->script);
      }
    }

    for (lineset = view_layer->freestyle_config.linesets.first; lineset; lineset = lineset->next) {
      if (lineset->group) {
        expand_doit(fd, mainvar, lineset->group);
      }
      expand_doit(fd, mainvar, lineset->linestyle);
    }
  }

  if (sce->gpd) {
    expand_doit(fd, mainvar, sce->gpd);
  }

  if (sce->ed) {
    Sequence *seq;

    SEQ_BEGIN (sce->ed, seq) {
      expand_idprops(fd, mainvar, seq->prop);

      if (seq->scene) {
        expand_doit(fd, mainvar, seq->scene);
      }
      if (seq->scene_camera) {
        expand_doit(fd, mainvar, seq->scene_camera);
      }
      if (seq->clip) {
        expand_doit(fd, mainvar, seq->clip);
      }
      if (seq->mask) {
        expand_doit(fd, mainvar, seq->mask);
      }
      if (seq->sound) {
        expand_doit(fd, mainvar, seq->sound);
      }

      if (seq->type == SEQ_TYPE_TEXT && seq->effectdata) {
        TextVars *data = seq->effectdata;
        expand_doit(fd, mainvar, data->text_font);
      }
    }
    SEQ_END;
  }

  if (sce->rigidbody_world) {
    expand_doit(fd, mainvar, sce->rigidbody_world->group);
    expand_doit(fd, mainvar, sce->rigidbody_world->constraints);
  }

  for (TimeMarker *marker = sce->markers.first; marker; marker = marker->next) {
    if (marker->camera) {
      expand_doit(fd, mainvar, marker->camera);
    }
  }

  expand_doit(fd, mainvar, sce->clip);

#ifdef USE_COLLECTION_COMPAT_28
  if (sce->collection) {
    expand_scene_collection(fd, mainvar, sce->collection);
  }
#endif

  if (sce->master_collection) {
    expand_collection(fd, mainvar, sce->master_collection);
  }

  if (sce->r.bake.cage_object) {
    expand_doit(fd, mainvar, sce->r.bake.cage_object);
  }
}

static void expand_camera(FileData *fd, Main *mainvar, Camera *ca)
{
  expand_doit(fd, mainvar, ca->ipo);  // XXX deprecated - old animation system

  for (CameraBGImage *bgpic = ca->bg_images.first; bgpic; bgpic = bgpic->next) {
    if (bgpic->source == CAM_BGIMG_SOURCE_IMAGE) {
      expand_doit(fd, mainvar, bgpic->ima);
    }
    else if (bgpic->source == CAM_BGIMG_SOURCE_MOVIE) {
      expand_doit(fd, mainvar, bgpic->ima);
    }
  }

  if (ca->adt) {
    expand_animdata(fd, mainvar, ca->adt);
  }
}

static void expand_cachefile(FileData *fd, Main *mainvar, CacheFile *cache_file)
{
  if (cache_file->adt) {
    expand_animdata(fd, mainvar, cache_file->adt);
  }
}

static void expand_speaker(FileData *fd, Main *mainvar, Speaker *spk)
{
  expand_doit(fd, mainvar, spk->sound);

  if (spk->adt) {
    expand_animdata(fd, mainvar, spk->adt);
  }
}

static void expand_sound(FileData *fd, Main *mainvar, bSound *snd)
{
  expand_doit(fd, mainvar, snd->ipo);  // XXX deprecated - old animation system
}

static void expand_lightprobe(FileData *fd, Main *mainvar, LightProbe *prb)
{
  if (prb->adt) {
    expand_animdata(fd, mainvar, prb->adt);
  }
}

static void expand_movieclip(FileData *fd, Main *mainvar, MovieClip *clip)
{
  if (clip->adt) {
    expand_animdata(fd, mainvar, clip->adt);
  }
}

static void expand_mask_parent(FileData *fd, Main *mainvar, MaskParent *parent)
{
  if (parent->id) {
    expand_doit(fd, mainvar, parent->id);
  }
}

static void expand_mask(FileData *fd, Main *mainvar, Mask *mask)
{
  MaskLayer *mask_layer;

  if (mask->adt) {
    expand_animdata(fd, mainvar, mask->adt);
  }

  for (mask_layer = mask->masklayers.first; mask_layer; mask_layer = mask_layer->next) {
    MaskSpline *spline;

    for (spline = mask_layer->splines.first; spline; spline = spline->next) {
      int i;

      for (i = 0; i < spline->tot_point; i++) {
        MaskSplinePoint *point = &spline->points[i];

        expand_mask_parent(fd, mainvar, &point->parent);
      }

      expand_mask_parent(fd, mainvar, &spline->parent);
    }
  }
}

static void expand_linestyle(FileData *fd, Main *mainvar, FreestyleLineStyle *linestyle)
{
  int a;
  LineStyleModifier *m;

  for (a = 0; a < MAX_MTEX; a++) {
    if (linestyle->mtex[a]) {
      expand_doit(fd, mainvar, linestyle->mtex[a]->tex);
      expand_doit(fd, mainvar, linestyle->mtex[a]->object);
    }
  }
  if (linestyle->nodetree) {
    expand_nodetree(fd, mainvar, linestyle->nodetree);
  }

  if (linestyle->adt) {
    expand_animdata(fd, mainvar, linestyle->adt);
  }
  for (m = linestyle->color_modifiers.first; m; m = m->next) {
    if (m->type == LS_MODIFIER_DISTANCE_FROM_OBJECT) {
      expand_doit(fd, mainvar, ((LineStyleColorModifier_DistanceFromObject *)m)->target);
    }
  }
  for (m = linestyle->alpha_modifiers.first; m; m = m->next) {
    if (m->type == LS_MODIFIER_DISTANCE_FROM_OBJECT) {
      expand_doit(fd, mainvar, ((LineStyleAlphaModifier_DistanceFromObject *)m)->target);
    }
  }
  for (m = linestyle->thickness_modifiers.first; m; m = m->next) {
    if (m->type == LS_MODIFIER_DISTANCE_FROM_OBJECT) {
      expand_doit(fd, mainvar, ((LineStyleThicknessModifier_DistanceFromObject *)m)->target);
    }
  }
}

static void expand_gpencil(FileData *fd, Main *mainvar, bGPdata *gpd)
{
  if (gpd->adt) {
    expand_animdata(fd, mainvar, gpd->adt);
  }

  for (bGPDlayer *gpl = gpd->layers.first; gpl; gpl = gpl->next) {
    expand_doit(fd, mainvar, gpl->parent);
  }

  for (int a = 0; a < gpd->totcol; a++) {
    expand_doit(fd, mainvar, gpd->mat[a]);
  }
}

static void expand_workspace(FileData *fd, Main *mainvar, WorkSpace *workspace)
{
  ListBase *layouts = BKE_workspace_layouts_get(workspace);

  for (WorkSpaceLayout *layout = layouts->first; layout; layout = layout->next) {
    expand_doit(fd, mainvar, BKE_workspace_layout_screen_get(layout));
  }
}

/**
 * Set the callback func used over all ID data found by \a BLO_expand_main func.
 *
 * \param expand_doit_func: Called for each ID block it finds.
 */
void BLO_main_expander(BLOExpandDoitCallback expand_doit_func)
{
  expand_doit = expand_doit_func;
}

/**
 * Loop over all ID data in Main to mark relations.
 * Set (id->tag & LIB_TAG_NEED_EXPAND) to mark expanding. Flags get cleared after expanding.
 *
 * \param fdhandle: usually filedata, or own handle.
 * \param mainvar: the Main database to expand.
 */
void BLO_expand_main(void *fdhandle, Main *mainvar)
{
  ListBase *lbarray[MAX_LIBARRAY];
  FileData *fd = fdhandle;
  ID *id;
  int a;
  bool do_it = true;

  while (do_it) {
    do_it = false;

    a = set_listbasepointers(mainvar, lbarray);
    while (a--) {
      id = lbarray[a]->first;
      while (id) {
        if (id->tag & LIB_TAG_NEED_EXPAND) {
          expand_id(fd, mainvar, id);
          expand_idprops(fd, mainvar, id->properties);

          switch (GS(id->name)) {
            case ID_OB:
              expand_object(fd, mainvar, (Object *)id);
              break;
            case ID_ME:
              expand_mesh(fd, mainvar, (Mesh *)id);
              break;
            case ID_CU:
              expand_curve(fd, mainvar, (Curve *)id);
              break;
            case ID_MB:
              expand_mball(fd, mainvar, (MetaBall *)id);
              break;
            case ID_SCE:
              expand_scene(fd, mainvar, (Scene *)id);
              break;
            case ID_MA:
              expand_material(fd, mainvar, (Material *)id);
              break;
            case ID_TE:
              expand_texture(fd, mainvar, (Tex *)id);
              break;
            case ID_WO:
              expand_world(fd, mainvar, (World *)id);
              break;
            case ID_LT:
              expand_lattice(fd, mainvar, (Lattice *)id);
              break;
            case ID_LA:
              expand_light(fd, mainvar, (Light *)id);
              break;
            case ID_KE:
              expand_key(fd, mainvar, (Key *)id);
              break;
            case ID_CA:
              expand_camera(fd, mainvar, (Camera *)id);
              break;
            case ID_SPK:
              expand_speaker(fd, mainvar, (Speaker *)id);
              break;
            case ID_SO:
              expand_sound(fd, mainvar, (bSound *)id);
              break;
            case ID_LP:
              expand_lightprobe(fd, mainvar, (LightProbe *)id);
              break;
            case ID_AR:
              expand_armature(fd, mainvar, (bArmature *)id);
              break;
            case ID_AC:
              expand_action(fd, mainvar, (bAction *)id);  // XXX deprecated - old animation system
              break;
            case ID_GR:
              expand_collection(fd, mainvar, (Collection *)id);
              break;
            case ID_NT:
              expand_nodetree(fd, mainvar, (bNodeTree *)id);
              break;
            case ID_BR:
              expand_brush(fd, mainvar, (Brush *)id);
              break;
            case ID_IP:
              expand_ipo(fd, mainvar, (Ipo *)id);  // XXX deprecated - old animation system
              break;
            case ID_PA:
              expand_particlesettings(fd, mainvar, (ParticleSettings *)id);
              break;
            case ID_MC:
              expand_movieclip(fd, mainvar, (MovieClip *)id);
              break;
            case ID_MSK:
              expand_mask(fd, mainvar, (Mask *)id);
              break;
            case ID_LS:
              expand_linestyle(fd, mainvar, (FreestyleLineStyle *)id);
              break;
            case ID_GD:
              expand_gpencil(fd, mainvar, (bGPdata *)id);
              break;
            case ID_CF:
              expand_cachefile(fd, mainvar, (CacheFile *)id);
              break;
            case ID_WS:
              expand_workspace(fd, mainvar, (WorkSpace *)id);
              break;
            default:
              break;
          }

          do_it = true;
          id->tag &= ~LIB_TAG_NEED_EXPAND;
        }
        id = id->next;
      }
    }
  }
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Library Linking (helper functions)
 * \{ */

static bool object_in_any_scene(Main *bmain, Object *ob)
{
  Scene *sce;

  for (sce = bmain->scenes.first; sce; sce = sce->id.next) {
    if (BKE_scene_object_find(sce, ob)) {
      return true;
    }
  }

  return false;
}

static bool object_in_any_collection(Main *bmain, Object *ob)
{
  Collection *collection;

  for (collection = bmain->collections.first; collection; collection = collection->id.next) {
    if (BKE_collection_has_object(collection, ob)) {
      return true;
    }
  }

  return false;
}

static void add_loose_objects_to_scene(Main *mainvar,
                                       Main *bmain,
                                       Scene *scene,
                                       ViewLayer *view_layer,
                                       const View3D *v3d,
                                       Library *lib,
                                       const short flag)
{
  Collection *active_collection = NULL;
  const bool do_append = (flag & FILE_LINK) == 0;

  BLI_assert(scene);

  /* Give all objects which are LIB_TAG_INDIRECT a base,
   * or for a collection when *lib has been set. */
  for (Object *ob = mainvar->objects.first; ob; ob = ob->id.next) {
    bool do_it = (ob->id.tag & LIB_TAG_DOIT) != 0;
    if (do_it || ((ob->id.tag & LIB_TAG_INDIRECT) && (ob->id.tag & LIB_TAG_PRE_EXISTING) == 0)) {
      if (do_append) {
        if (ob->id.us == 0) {
          do_it = true;
        }
        else if ((ob->id.lib == lib) && (object_in_any_collection(bmain, ob) == 0)) {
          /* When appending, make sure any indirectly loaded object gets a base,
           * when they are not part of any collection yet. */
          do_it = true;
        }
      }

      if (do_it) {
        /* Find or add collection as needed. */
        if (active_collection == NULL) {
          if (flag & FILE_ACTIVE_COLLECTION) {
            LayerCollection *lc = BKE_layer_collection_get_active(view_layer);
            active_collection = lc->collection;
          }
          else {
            active_collection = BKE_collection_add(bmain, scene->master_collection, NULL);
          }
        }

        CLAMP_MIN(ob->id.us, 0);
        ob->mode = OB_MODE_OBJECT;

        BKE_collection_object_add(bmain, active_collection, ob);
        Base *base = BKE_view_layer_base_find(view_layer, ob);

        if (v3d != NULL) {
          base->local_view_bits |= v3d->local_view_uuid;
        }

        if (flag & FILE_AUTOSELECT) {
          base->flag |= BASE_SELECTED;
          /* Do NOT make base active here! screws up GUI stuff,
           * if you want it do it on src/ level. */
        }

        BKE_scene_object_base_flag_sync_from_base(base);

        ob->id.tag &= ~LIB_TAG_INDIRECT;
        ob->id.tag |= LIB_TAG_EXTERN;
      }
    }
  }
}

static void add_collections_to_scene(Main *mainvar,
                                     Main *bmain,
                                     Scene *scene,
                                     ViewLayer *view_layer,
                                     const View3D *v3d,
                                     Library *lib,
                                     const short flag)
{
  Collection *active_collection = scene->master_collection;
  if (flag & FILE_ACTIVE_COLLECTION) {
    LayerCollection *lc = BKE_layer_collection_get_active(view_layer);
    active_collection = lc->collection;
  }

  /* Give all objects which are tagged a base. */
  for (Collection *collection = mainvar->collections.first; collection;
       collection = collection->id.next) {
    if ((flag & FILE_GROUP_INSTANCE) && (collection->id.tag & LIB_TAG_DOIT)) {
      /* Any indirect collection should not have been tagged. */
      BLI_assert((collection->id.tag & LIB_TAG_INDIRECT) == 0);

      /* BKE_object_add(...) messes with the selection. */
      Object *ob = BKE_object_add_only_object(bmain, OB_EMPTY, collection->id.name + 2);
      ob->type = OB_EMPTY;

      BKE_collection_object_add(bmain, active_collection, ob);
      Base *base = BKE_view_layer_base_find(view_layer, ob);

      if (v3d != NULL) {
        base->local_view_bits |= v3d->local_view_uuid;
      }

      if (base->flag & BASE_SELECTABLE) {
        base->flag |= BASE_SELECTED;
      }

      BKE_scene_object_base_flag_sync_from_base(base);
      DEG_id_tag_update(&ob->id, ID_RECALC_TRANSFORM | ID_RECALC_GEOMETRY | ID_RECALC_ANIMATION);
      view_layer->basact = base;

      /* Assign the collection. */
      ob->instance_collection = collection;
      id_us_plus(&collection->id);
      ob->transflag |= OB_DUPLICOLLECTION;
      copy_v3_v3(ob->loc, scene->cursor.location);
    }
    /* We do not want to force instantiation of indirectly linked collections,
     * not even when appending. Users can now easily instantiate collections (and their objects)
     * as needed by themsleves. See T67032. */
    else if ((collection->id.tag & LIB_TAG_INDIRECT) == 0) {
      bool do_add_collection = (collection->id.tag & LIB_TAG_DOIT) != 0;
      if (!do_add_collection) {
        /* We need to check that objects in that collections are already instantiated in a scene.
         * Otherwise, it's better to add the collection to the scene's active collection, than to
         * instantiate its objects in active scene's collection directly. See T61141.
         * Note that we only check object directly into that collection,
         * not recursively into its children.
         */
        for (CollectionObject *coll_ob = collection->gobject.first; coll_ob != NULL;
             coll_ob = coll_ob->next) {
          Object *ob = coll_ob->ob;
          if ((ob->id.tag & (LIB_TAG_PRE_EXISTING | LIB_TAG_DOIT | LIB_TAG_INDIRECT)) == 0 &&
              (ob->id.lib == lib) && (object_in_any_scene(bmain, ob) == 0)) {
            do_add_collection = true;
            break;
          }
        }
      }
      if (do_add_collection) {
        /* Add collection as child of active collection. */
        BKE_collection_child_add(bmain, active_collection, collection);

        if (flag & FILE_AUTOSELECT) {
          for (CollectionObject *coll_ob = collection->gobject.first; coll_ob != NULL;
               coll_ob = coll_ob->next) {
            Object *ob = coll_ob->ob;
            Base *base = BKE_view_layer_base_find(view_layer, ob);
            if (base) {
              base->flag |= BASE_SELECTED;
              BKE_scene_object_base_flag_sync_from_base(base);
            }
          }
        }

        /* Those are kept for safety and consistency, but should not be needed anymore? */
        collection->id.tag &= ~LIB_TAG_INDIRECT;
        collection->id.tag |= LIB_TAG_EXTERN;
      }
    }
  }
}

/* returns true if the item was found
 * but it may already have already been appended/linked */
static ID *link_named_part(
    Main *mainl, FileData *fd, const short idcode, const char *name, const int flag)
{
  BHead *bhead = find_bhead_from_code_name(fd, idcode, name);
  ID *id;

  const bool use_placeholders = (flag & BLO_LIBLINK_USE_PLACEHOLDERS) != 0;
  const bool force_indirect = (flag & BLO_LIBLINK_FORCE_INDIRECT) != 0;

  BLI_assert(BKE_idcode_is_linkable(idcode) && BKE_idcode_is_valid(idcode));

  if (bhead) {
    id = is_yet_read(fd, mainl, bhead);
    if (id == NULL) {
      /* not read yet */
      const int tag = force_indirect ? LIB_TAG_INDIRECT : LIB_TAG_EXTERN;
      read_libblock(fd, mainl, bhead, tag | LIB_TAG_NEED_EXPAND, &id);

      if (id) {
        /* sort by name in list */
        ListBase *lb = which_libbase(mainl, idcode);
        id_sort_by_name(lb, id);
      }
    }
    else {
      /* already linked */
      if (G.debug) {
        printf("append: already linked\n");
      }
      oldnewmap_insert(fd->libmap, bhead->old, id, bhead->code);
      if (!force_indirect && (id->tag & LIB_TAG_INDIRECT)) {
        id->tag &= ~LIB_TAG_INDIRECT;
        id->tag |= LIB_TAG_EXTERN;
      }
    }
  }
  else if (use_placeholders) {
    /* XXX flag part is weak! */
    id = create_placeholder(
        mainl, idcode, name, force_indirect ? LIB_TAG_INDIRECT : LIB_TAG_EXTERN);
  }
  else {
    id = NULL;
  }

  /* if we found the id but the id is NULL, this is really bad */
  BLI_assert(!((bhead != NULL) && (id == NULL)));

  return id;
}

/**
 * Simple reader for copy/paste buffers.
 */
int BLO_library_link_copypaste(Main *mainl, BlendHandle *bh, const unsigned int id_types_mask)
{
  FileData *fd = (FileData *)(bh);
  BHead *bhead;
  int num_directly_linked = 0;

  for (bhead = blo_bhead_first(fd); bhead; bhead = blo_bhead_next(fd, bhead)) {
    ID *id = NULL;

    if (bhead->code == ENDB) {
      break;
    }

    if (BKE_idcode_is_valid(bhead->code) && BKE_idcode_is_linkable(bhead->code) &&
        (id_types_mask == 0 ||
         (BKE_idcode_to_idfilter((short)bhead->code) & id_types_mask) != 0)) {
      read_libblock(fd, mainl, bhead, LIB_TAG_NEED_EXPAND | LIB_TAG_INDIRECT, &id);
      num_directly_linked++;
    }

    if (id) {
      /* sort by name in list */
      ListBase *lb = which_libbase(mainl, GS(id->name));
      id_sort_by_name(lb, id);

      if (bhead->code == ID_OB) {
        /* Instead of instancing Base's directly, postpone until after collections are loaded
         * otherwise the base's flag is set incorrectly when collections are used */
        Object *ob = (Object *)id;
        ob->mode = OB_MODE_OBJECT;
        /* ensure add_loose_objects_to_scene runs on this object */
        BLI_assert(id->us == 0);
      }
    }
  }

  return num_directly_linked;
}

static ID *link_named_part_ex(
    Main *mainl, FileData *fd, const short idcode, const char *name, const int flag)
{
  ID *id = link_named_part(mainl, fd, idcode, name, flag);

  if (id && (GS(id->name) == ID_OB)) {
    /* Tag as loose object needing to be instantiated somewhere... */
    id->tag |= LIB_TAG_DOIT;
  }
  else if (id && (GS(id->name) == ID_GR)) {
    /* tag as needing to be instantiated or linked */
    id->tag |= LIB_TAG_DOIT;
  }

  return id;
}

/**
 * Link a named data-block from an external blend file.
 *
 * \param mainl: The main database to link from (not the active one).
 * \param bh: The blender file handle.
 * \param idcode: The kind of data-block to link.
 * \param name: The name of the data-block (without the 2 char ID prefix).
 * \return the linked ID when found.
 */
ID *BLO_library_link_named_part(Main *mainl,
                                BlendHandle **bh,
                                const short idcode,
                                const char *name)
{
  FileData *fd = (FileData *)(*bh);
  return link_named_part(mainl, fd, idcode, name, 0);
}

/**
 * Link a named data-block from an external blend file.
 * Optionally instantiate the object/collection in the scene when the flags are set.
 *
 * \param mainl: The main database to link from (not the active one).
 * \param bh: The blender file handle.
 * \param idcode: The kind of data-block to link.
 * \param name: The name of the data-block (without the 2 char ID prefix).
 * \param flag: Options for linking, used for instantiating.
 * \param scene: The scene in which to instantiate objects/collections
 * (if NULL, no instantiation is done).
 * \param v3d: The active 3D viewport.
 * (only to define active layers for instantiated objects & collections, can be NULL).
 * \return the linked ID when found.
 */
ID *BLO_library_link_named_part_ex(
    Main *mainl, BlendHandle **bh, const short idcode, const char *name, const int flag)
{
  FileData *fd = (FileData *)(*bh);
  return link_named_part_ex(mainl, fd, idcode, name, flag);
}

/* common routine to append/link something from a library */

static Main *library_link_begin(Main *mainvar, FileData **fd, const char *filepath)
{
  Main *mainl;

  (*fd)->mainlist = MEM_callocN(sizeof(ListBase), "FileData.mainlist");

  /* clear for objects and collections instantiating tag */
  BKE_main_id_tag_listbase(&(mainvar->objects), LIB_TAG_DOIT, false);
  BKE_main_id_tag_listbase(&(mainvar->collections), LIB_TAG_DOIT, false);

  /* make mains */
  blo_split_main((*fd)->mainlist, mainvar);

  /* which one do we need? */
  mainl = blo_find_main(*fd, filepath, BKE_main_blendfile_path(mainvar));

  /* needed for do_version */
  mainl->versionfile = (*fd)->fileversion;
  read_file_version(*fd, mainl);
#ifdef USE_GHASH_BHEAD
  read_file_bhead_idname_map_create(*fd);
#endif

  return mainl;
}

/**
 * Initialize the BlendHandle for linking library data.
 *
 * \param mainvar: The current main database, e.g. #G_MAIN or #CTX_data_main(C).
 * \param bh: A blender file handle as returned by
 * #BLO_blendhandle_from_file or #BLO_blendhandle_from_memory.
 * \param filepath: Used for relative linking, copied to the \a lib->name.
 * \return the library Main, to be passed to #BLO_library_append_named_part as \a mainl.
 */
Main *BLO_library_link_begin(Main *mainvar, BlendHandle **bh, const char *filepath)
{
  FileData *fd = (FileData *)(*bh);
  return library_link_begin(mainvar, &fd, filepath);
}

static void split_main_newid(Main *mainptr, Main *main_newid)
{
  /* We only copy the necessary subset of data in this temp main. */
  main_newid->versionfile = mainptr->versionfile;
  main_newid->subversionfile = mainptr->subversionfile;
  BLI_strncpy(main_newid->name, mainptr->name, sizeof(main_newid->name));
  main_newid->curlib = mainptr->curlib;

  ListBase *lbarray[MAX_LIBARRAY];
  ListBase *lbarray_newid[MAX_LIBARRAY];
  int i = set_listbasepointers(mainptr, lbarray);
  set_listbasepointers(main_newid, lbarray_newid);
  while (i--) {
    BLI_listbase_clear(lbarray_newid[i]);

    for (ID *id = lbarray[i]->first, *idnext; id; id = idnext) {
      idnext = id->next;

      if (id->tag & LIB_TAG_NEW) {
        BLI_remlink(lbarray[i], id);
        BLI_addtail(lbarray_newid[i], id);
      }
    }
  }
}

/* scene and v3d may be NULL. */
static void library_link_end(Main *mainl,
                             FileData **fd,
                             const short flag,
                             Main *bmain,
                             Scene *scene,
                             ViewLayer *view_layer,
                             const View3D *v3d)
{
  Main *mainvar;
  Library *curlib;

  /* expander now is callback function */
  BLO_main_expander(expand_doit_library);

  /* make main consistent */
  BLO_expand_main(*fd, mainl);

  /* do this when expand found other libs */
  read_libraries(*fd, (*fd)->mainlist);

  curlib = mainl->curlib;

  /* make the lib path relative if required */
  if (flag & FILE_RELPATH) {
    /* use the full path, this could have been read by other library even */
    BLI_strncpy(curlib->name, curlib->filepath, sizeof(curlib->name));

    /* uses current .blend file as reference */
    BLI_path_rel(curlib->name, BKE_main_blendfile_path_from_global());
  }

  blo_join_main((*fd)->mainlist);
  mainvar = (*fd)->mainlist->first;
  mainl = NULL; /* blo_join_main free's mainl, cant use anymore */

  lib_link_all(*fd, mainvar);
  BKE_collections_after_lib_link(mainvar);

  /* Yep, second splitting... but this is a very cheap operation, so no big deal. */
  blo_split_main((*fd)->mainlist, mainvar);
  Main *main_newid = BKE_main_new();
  for (mainvar = ((Main *)(*fd)->mainlist->first)->next; mainvar; mainvar = mainvar->next) {
    BLI_assert(mainvar->versionfile != 0);
    /* We need to split out IDs already existing,
     * or they will go again through do_versions - bad, very bad! */
    split_main_newid(mainvar, main_newid);

    do_versions_after_linking(main_newid);

    add_main_to_main(mainvar, main_newid);
  }
  BKE_main_free(main_newid);
  blo_join_main((*fd)->mainlist);
  mainvar = (*fd)->mainlist->first;
  MEM_freeN((*fd)->mainlist);

  /* After all data has been read and versioned, uses LIB_TAG_NEW. */
  ntreeUpdateAllNew(mainvar);

  placeholders_ensure_valid(mainvar);

  BKE_main_id_tag_all(mainvar, LIB_TAG_NEW, false);

  fix_relpaths_library(BKE_main_blendfile_path(mainvar),
                       mainvar); /* make all relative paths, relative to the open blend file */

  /* Give a base to loose objects and collections.
   * Only directly linked objects & collections are instantiated by
   * `BLO_library_link_named_part_ex()` & co,
   * here we handle indirect ones and other possible edge-cases. */
  if (scene) {
    add_collections_to_scene(mainvar, bmain, scene, view_layer, v3d, curlib, flag);
    add_loose_objects_to_scene(mainvar, bmain, scene, view_layer, v3d, curlib, flag);
  }
  else {
    /* printf("library_append_end, scene is NULL (objects wont get bases)\n"); */
  }

  /* Clear objects and collections instantiating tag. */
  BKE_main_id_tag_listbase(&(mainvar->objects), LIB_TAG_DOIT, false);
  BKE_main_id_tag_listbase(&(mainvar->collections), LIB_TAG_DOIT, false);

  /* patch to prevent switch_endian happens twice */
  if ((*fd)->flags & FD_FLAGS_SWITCH_ENDIAN) {
    blo_filedata_free(*fd);
    *fd = NULL;
  }
}

/**
 * Finalize linking from a given .blend file (library).
 * Optionally instance the indirect object/collection in the scene when the flags are set.
 * \note Do not use \a bh after calling this function, it may frees it.
 *
 * \param mainl: The main database to link from (not the active one).
 * \param bh: The blender file handle (WARNING! may be freed by this function!).
 * \param flag: Options for linking, used for instantiating.
 * \param bmain: The main database in which to instantiate objects/collections
 * \param scene: The scene in which to instantiate objects/collections
 * (if NULL, no instantiation is done).
 * \param view_layer: The scene layer in which to instantiate objects/collections
 * (if NULL, no instantiation is done).
 * \param v3d: The active 3D viewport
 * (only to define local-view for instantiated objects & groups, can be NULL).
 */
void BLO_library_link_end(Main *mainl,
                          BlendHandle **bh,
                          int flag,
                          Main *bmain,
                          Scene *scene,
                          ViewLayer *view_layer,
                          const View3D *v3d)
{
  FileData *fd = (FileData *)(*bh);
  library_link_end(mainl, &fd, flag, bmain, scene, view_layer, v3d);
  *bh = (BlendHandle *)fd;
}

void *BLO_library_read_struct(FileData *fd, BHead *bh, const char *blockname)
{
  return read_struct(fd, bh, blockname);
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Library Reading
 * \{ */

static int has_linked_ids_to_read(Main *mainvar)
{
  ListBase *lbarray[MAX_LIBARRAY];
  int a = set_listbasepointers(mainvar, lbarray);

  while (a--) {
    for (ID *id = lbarray[a]->first; id; id = id->next) {
      if (id->tag & LIB_TAG_ID_LINK_PLACEHOLDER) {
        return true;
      }
    }
  }

  return false;
}

static void read_library_linked_id(
    ReportList *reports, FileData *fd, Main *mainvar, ID *id, ID **r_id)
{
  BHead *bhead = NULL;
  const bool is_valid = BKE_idcode_is_linkable(GS(id->name)) || ((id->tag & LIB_TAG_EXTERN) == 0);

  if (fd) {
    bhead = find_bhead_from_idname(fd, id->name);
  }

  if (!is_valid) {
    blo_reportf_wrap(reports,
                     RPT_ERROR,
                     TIP_("LIB: %s: '%s' is directly linked from '%s' (parent '%s'), but is a "
                          "non-linkable data type"),
                     BKE_idcode_to_name(GS(id->name)),
                     id->name + 2,
                     mainvar->curlib->filepath,
                     library_parent_filepath(mainvar->curlib));
  }

  id->tag &= ~LIB_TAG_ID_LINK_PLACEHOLDER;

  if (bhead) {
    id->tag |= LIB_TAG_NEED_EXPAND;
    // printf("read lib block %s\n", id->name);
    read_libblock(fd, mainvar, bhead, id->tag, r_id);
  }
  else {
    blo_reportf_wrap(reports,
                     RPT_WARNING,
                     TIP_("LIB: %s: '%s' missing from '%s', parent '%s'"),
                     BKE_idcode_to_name(GS(id->name)),
                     id->name + 2,
                     mainvar->curlib->filepath,
                     library_parent_filepath(mainvar->curlib));

    /* Generate a placeholder for this ID (simplified version of read_libblock actually...). */
    if (r_id) {
      *r_id = is_valid ? create_placeholder(mainvar, GS(id->name), id->name + 2, id->tag) : NULL;
    }
  }
}

static void read_library_linked_ids(FileData *basefd,
                                    FileData *fd,
                                    ListBase *mainlist,
                                    Main *mainvar)
{
  GHash *loaded_ids = BLI_ghash_str_new(__func__);

  ListBase *lbarray[MAX_LIBARRAY];
  int a = set_listbasepointers(mainvar, lbarray);

  while (a--) {
    ID *id = lbarray[a]->first;
    ListBase pending_free_ids = {NULL};

    while (id) {
      ID *id_next = id->next;
      if (id->tag & LIB_TAG_ID_LINK_PLACEHOLDER) {
        BLI_remlink(lbarray[a], id);

        /* When playing with lib renaming and such, you may end with cases where
         * you have more than one linked ID of the same data-block from same
         * library. This is absolutely horrible, hence we use a ghash to ensure
         * we go back to a single linked data when loading the file. */
        ID **realid = NULL;
        if (!BLI_ghash_ensure_p(loaded_ids, id->name, (void ***)&realid)) {
          read_library_linked_id(basefd->reports, fd, mainvar, id, realid);
        }

        /* realid shall never be NULL - unless some source file/lib is broken
         * (known case: some directly linked shapekey from a missing lib...). */
        /* BLI_assert(*realid != NULL); */

        /* Now that we have a real ID, replace all pointers to placeholders in
         * fd->libmap with pointers to the real data-blocks. We do this for all
         * libraries since multiple might be referencing this ID. */
        change_link_placeholder_to_real_ID_pointer(mainlist, basefd, id, *realid);

        /* We cannot free old lib-ref placeholder ID here anymore, since we use
         * its name as key in loaded_ids hash. */
        BLI_addtail(&pending_free_ids, id);
      }
      id = id_next;
    }

    /* Clear GHash and free link placeholder IDs of the current type. */
    BLI_ghash_clear(loaded_ids, NULL, NULL);
    BLI_freelistN(&pending_free_ids);
  }

  BLI_ghash_free(loaded_ids, NULL, NULL);
}

static FileData *read_library_file_data(FileData *basefd,
                                        ListBase *mainlist,
                                        Main *mainl,
                                        Main *mainptr)
{
  FileData *fd = mainptr->curlib->filedata;

  if (fd != NULL) {
    /* File already open. */
    return fd;
  }

  if (mainptr->curlib->packedfile) {
    /* Read packed file. */
    PackedFile *pf = mainptr->curlib->packedfile;

    blo_reportf_wrap(basefd->reports,
                     RPT_INFO,
                     TIP_("Read packed library:  '%s', parent '%s'"),
                     mainptr->curlib->name,
                     library_parent_filepath(mainptr->curlib));
    fd = blo_filedata_from_memory(pf->data, pf->size, basefd->reports);

    /* Needed for library_append and read_libraries. */
    BLI_strncpy(fd->relabase, mainptr->curlib->filepath, sizeof(fd->relabase));
  }
  else {
    /* Read file on disk. */
    blo_reportf_wrap(basefd->reports,
                     RPT_INFO,
                     TIP_("Read library:  '%s', '%s', parent '%s'"),
                     mainptr->curlib->filepath,
                     mainptr->curlib->name,
                     library_parent_filepath(mainptr->curlib));
    fd = blo_filedata_from_file(mainptr->curlib->filepath, basefd->reports);
  }

  if (fd) {
    /* Share the mainlist, so all libraries are added immediately in a
     * single list. It used to be that all FileData's had their own list,
     * but with indirectly linking this meant we didn't catch duplicate
     * libraries properly. */
    fd->mainlist = mainlist;

    fd->reports = basefd->reports;

    if (fd->libmap) {
      oldnewmap_free(fd->libmap);
    }

    fd->libmap = oldnewmap_new();

    mainptr->curlib->filedata = fd;
    mainptr->versionfile = fd->fileversion;

    /* subversion */
    read_file_version(fd, mainptr);
#ifdef USE_GHASH_BHEAD
    read_file_bhead_idname_map_create(fd);
#endif
  }
  else {
    mainptr->curlib->filedata = NULL;
    mainptr->curlib->id.tag |= LIB_TAG_MISSING;
    /* Set lib version to current main one... Makes assert later happy. */
    mainptr->versionfile = mainptr->curlib->versionfile = mainl->versionfile;
    mainptr->subversionfile = mainptr->curlib->subversionfile = mainl->subversionfile;
  }

  if (fd == NULL) {
    blo_reportf_wrap(
        basefd->reports, RPT_WARNING, TIP_("Cannot find lib '%s'"), mainptr->curlib->filepath);
  }

  return fd;
}

static void read_libraries(FileData *basefd, ListBase *mainlist)
{
  Main *mainl = mainlist->first;
  bool do_it = true;

  /* Expander is now callback function. */
  BLO_main_expander(expand_doit_library);

  /* At this point the base blend file has been read, and each library blend
   * encountered so far has a main with placeholders for linked data-blocks.
   *
   * Now we will read the library blend files and replace the placeholders
   * with actual data-blocks. We loop over library mains multiple times in
   * case a library needs to link additional data-blocks from another library
   * that had been read previously. */
  while (do_it) {
    do_it = false;

    /* Loop over mains of all library blend files encountered so far. Note
     * this list gets longer as more indirectly library blends are found. */
    for (Main *mainptr = mainl->next; mainptr; mainptr = mainptr->next) {
      /* Does this library have any more linked data-blocks we need to read? */
      if (has_linked_ids_to_read(mainptr)) {
#if 0
        printf("Reading linked data-blocks from %s (%s)\n",
               mainptr->curlib->id.name,
               mainptr->curlib->name);
#endif

        /* Open file if it has not been done yet. */
        FileData *fd = read_library_file_data(basefd, mainlist, mainl, mainptr);

        if (fd) {
          do_it = true;
        }

        /* Read linked data-locks for each link placeholder, and replace
         * the placeholder with the real data-lock. */
        read_library_linked_ids(basefd, fd, mainlist, mainptr);

        /* Test if linked data-locks need to read further linked data-locks
         * and create link placeholders for them. */
        BLO_expand_main(fd, mainptr);
      }
    }
  }

  Main *main_newid = BKE_main_new();
  for (Main *mainptr = mainl->next; mainptr; mainptr = mainptr->next) {
    /* Do versioning for newly added linked data-locks. If no data-locks
     * were read from a library versionfile will still be zero and we can
     * skip it. */
    if (mainptr->versionfile) {
      /* Split out already existing IDs to avoid them going through
       * do_versions multiple times, which would have bad consequences. */
      split_main_newid(mainptr, main_newid);

      /* File data can be zero with link/append. */
      if (mainptr->curlib->filedata) {
        do_versions(mainptr->curlib->filedata, mainptr->curlib, main_newid);
      }
      else {
        do_versions(basefd, NULL, main_newid);
      }

      add_main_to_main(mainptr, main_newid);
    }

    /* Lib linking. */
    if (mainptr->curlib->filedata) {
      lib_link_all(mainptr->curlib->filedata, mainptr);
    }

    /* Free file data we no longer need. */
    if (mainptr->curlib->filedata) {
      blo_filedata_free(mainptr->curlib->filedata);
    }
    mainptr->curlib->filedata = NULL;
  }
  BKE_main_free(main_newid);
}

/** \} */