Cleanup/refactor: Rename BKE_library files to BKE_lib.

Note that `BKE_library.h`/`library.c` were renamed to `BKE_lib_id.h`/`lib_id.c` to avoid having a too generic name here. Part of T72604.
2020-02-10 12:58:59 +01:00
parent ae863f34df
commit 56116bbdf4
250 changed files with 362 additions and 362 deletions
--- a/source/blender/blenkernel/intern/lib_override.c
+++ b/source/blender/blenkernel/intern/lib_override.c
@@ -0,0 +1,954 @@
+/*
+ * 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) 2016 by Blender Foundation.
+ * All rights reserved.
+ */
+
+/** \file
+ * \ingroup bke
+ */
+
+#include <stdlib.h>
+#include <string.h>
+
+#include "MEM_guardedalloc.h"
+
+#include "DNA_ID.h"
+#include "DNA_object_types.h"
+
+#include "DEG_depsgraph.h"
+
+#include "BKE_armature.h"
+#include "BKE_lib_id.h"
+#include "BKE_lib_override.h"
+#include "BKE_lib_remap.h"
+#include "BKE_main.h"
+
+#include "BLI_utildefines.h"
+#include "BLI_ghash.h"
+#include "BLI_listbase.h"
+#include "BLI_string.h"
+
+#include "RNA_access.h"
+#include "RNA_types.h"
+
+#include "PIL_time.h"
+#include "PIL_time_utildefines.h"
+
+#define OVERRIDE_AUTO_CHECK_DELAY 0.2 /* 200ms between auto-override checks. */
+
+static void bke_override_property_copy(IDOverrideLibraryProperty *op_dst,
+                                       IDOverrideLibraryProperty *op_src);
+static void bke_override_property_operation_copy(IDOverrideLibraryPropertyOperation *opop_dst,
+                                                 IDOverrideLibraryPropertyOperation *opop_src);
+
+static void bke_override_property_clear(IDOverrideLibraryProperty *op);
+static void bke_override_property_operation_clear(IDOverrideLibraryPropertyOperation *opop);
+
+/* Temp, for until library override is ready and tested enough to go 'public',
+ * we hide it by default in UI and such. */
+static bool _override_library_enabled = true;
+
+void BKE_override_library_enable(const bool do_enable)
+{
+  _override_library_enabled = do_enable;
+}
+
+bool BKE_override_library_is_enabled()
+{
+  return _override_library_enabled;
+}
+
+/** Initialize empty overriding of \a reference_id by \a local_id. */
+IDOverrideLibrary *BKE_override_library_init(ID *local_id, ID *reference_id)
+{
+  /* If reference_id is NULL, we are creating an override template for purely local data.
+   * Else, reference *must* be linked data. */
+  BLI_assert(reference_id == NULL || reference_id->lib != NULL);
+  BLI_assert(local_id->override_library == NULL);
+
+  ID *ancestor_id;
+  for (ancestor_id = reference_id; ancestor_id != NULL && ancestor_id->override_library != NULL &&
+                                   ancestor_id->override_library->reference != NULL;
+       ancestor_id = ancestor_id->override_library->reference) {
+    /* pass */
+  }
+
+  if (ancestor_id != NULL && ancestor_id->override_library != NULL) {
+    /* Original ID has a template, use it! */
+    BKE_override_library_copy(local_id, ancestor_id);
+    if (local_id->override_library->reference != reference_id) {
+      id_us_min(local_id->override_library->reference);
+      local_id->override_library->reference = reference_id;
+      id_us_plus(local_id->override_library->reference);
+    }
+    return local_id->override_library;
+  }
+
+  /* Else, generate new empty override. */
+  local_id->override_library = MEM_callocN(sizeof(*local_id->override_library), __func__);
+  local_id->override_library->reference = reference_id;
+  id_us_plus(local_id->override_library->reference);
+  local_id->tag &= ~LIB_TAG_OVERRIDE_LIBRARY_REFOK;
+  /* TODO do we want to add tag or flag to referee to mark it as such? */
+  return local_id->override_library;
+}
+
+/** Deep copy of a whole override from \a src_id to \a dst_id. */
+void BKE_override_library_copy(ID *dst_id, const ID *src_id)
+{
+  BLI_assert(src_id->override_library != NULL);
+
+  if (dst_id->override_library != NULL) {
+    if (src_id->override_library == NULL) {
+      BKE_override_library_free(&dst_id->override_library, true);
+      return;
+    }
+    else {
+      BKE_override_library_clear(dst_id->override_library, true);
+    }
+  }
+  else if (src_id->override_library == NULL) {
+    return;
+  }
+  else {
+    BKE_override_library_init(dst_id, NULL);
+  }
+
+  /* Source is already overriding data, we copy it but reuse its reference for dest ID.
+   * otherwise, source is only an override template, it then becomes reference of dest ID. */
+  dst_id->override_library->reference = src_id->override_library->reference ?
+                                            src_id->override_library->reference :
+                                            (ID *)src_id;
+  id_us_plus(dst_id->override_library->reference);
+
+  BLI_duplicatelist(&dst_id->override_library->properties, &src_id->override_library->properties);
+  for (IDOverrideLibraryProperty *op_dst = dst_id->override_library->properties.first,
+                                 *op_src = src_id->override_library->properties.first;
+       op_dst;
+       op_dst = op_dst->next, op_src = op_src->next) {
+    bke_override_property_copy(op_dst, op_src);
+  }
+
+  dst_id->tag &= ~LIB_TAG_OVERRIDE_LIBRARY_REFOK;
+}
+
+/** Clear any overriding data from given \a override. */
+void BKE_override_library_clear(IDOverrideLibrary *override, const bool do_id_user)
+{
+  BLI_assert(override != NULL);
+
+  if (override->runtime != NULL) {
+    BLI_ghash_clear(override->runtime, NULL, NULL);
+  }
+
+  for (IDOverrideLibraryProperty *op = override->properties.first; op; op = op->next) {
+    bke_override_property_clear(op);
+  }
+  BLI_freelistN(&override->properties);
+
+  if (do_id_user) {
+    id_us_min(override->reference);
+    /* override->storage should never be refcounted... */
+  }
+}
+
+/** Free given \a override. */
+void BKE_override_library_free(struct IDOverrideLibrary **override, const bool do_id_user)
+{
+  BLI_assert(*override != NULL);
+
+  if ((*override)->runtime != NULL) {
+    BLI_ghash_free((*override)->runtime, NULL, NULL);
+    (*override)->runtime = NULL;
+  }
+
+  BKE_override_library_clear(*override, do_id_user);
+  MEM_freeN(*override);
+  *override = NULL;
+}
+
+static ID *override_library_create_from(Main *bmain, ID *reference_id)
+{
+  ID *local_id;
+
+  if (!BKE_id_copy(bmain, reference_id, (ID **)&local_id)) {
+    return NULL;
+  }
+  id_us_min(local_id);
+
+  BKE_override_library_init(local_id, reference_id);
+  local_id->override_library->flag |= OVERRIDE_LIBRARY_AUTO;
+
+  return local_id;
+}
+
+/** Create an overridden local copy of linked reference. */
+ID *BKE_override_library_create_from_id(Main *bmain, ID *reference_id, const bool do_tagged_remap)
+{
+  BLI_assert(reference_id != NULL);
+  BLI_assert(reference_id->lib != NULL);
+
+  ID *local_id = override_library_create_from(bmain, reference_id);
+
+  if (do_tagged_remap) {
+    ID *other_id;
+    FOREACH_MAIN_ID_BEGIN (bmain, other_id) {
+      if ((other_id->tag & LIB_TAG_DOIT) != 0 && other_id->lib == NULL) {
+        /* Note that using ID_REMAP_SKIP_INDIRECT_USAGE below is superfluous, as we only remap
+         * local IDs usages anyway... */
+        BKE_libblock_relink_ex(bmain,
+                               other_id,
+                               reference_id,
+                               local_id,
+                               ID_REMAP_SKIP_INDIRECT_USAGE | ID_REMAP_SKIP_OVERRIDE_LIBRARY);
+      }
+    }
+    FOREACH_MAIN_ID_END;
+  }
+
+  return local_id;
+}
+
+/**
+ * Create overridden local copies of all tagged data-blocks in given Main.
+ *
+ * \note Set id->newid of overridden libs with newly created overrides,
+ * caller is responsible to clean those pointers before/after usage as needed.
+ *
+ * \note By default, it will only remap newly created local overriding data-blocks between
+ * themselves, to avoid 'enforcing' those overrides into all other usages of the linked data in
+ * main. You can add more local IDs to be remapped to use new overriding ones by setting their
+ * LIB_TAG_DOIT tag.
+ *
+ * \return \a true on success, \a false otherwise.
+ */
+bool BKE_override_library_create_from_tag(Main *bmain)
+{
+  ID *reference_id;
+  bool ret = true;
+
+  ListBase todo_ids = {NULL};
+  LinkData *todo_id_iter;
+
+  /* Get all IDs we want to override. */
+  FOREACH_MAIN_ID_BEGIN (bmain, reference_id) {
+    if ((reference_id->tag & LIB_TAG_DOIT) != 0 && reference_id->lib != NULL) {
+      todo_id_iter = MEM_callocN(sizeof(*todo_id_iter), __func__);
+      todo_id_iter->data = reference_id;
+      BLI_addtail(&todo_ids, todo_id_iter);
+    }
+  }
+  FOREACH_MAIN_ID_END;
+
+  /* Override the IDs. */
+  for (todo_id_iter = todo_ids.first; todo_id_iter != NULL; todo_id_iter = todo_id_iter->next) {
+    reference_id = todo_id_iter->data;
+    if ((reference_id->newid = override_library_create_from(bmain, reference_id)) == NULL) {
+      ret = false;
+    }
+    else {
+      /* We also tag the new IDs so that in next step we can remap their pointers too. */
+      reference_id->newid->tag |= LIB_TAG_DOIT;
+    }
+  }
+
+  /* Only remap new local ID's pointers, we don't want to force our new overrides onto our whole
+   * existing linked IDs usages. */
+  for (todo_id_iter = todo_ids.first; todo_id_iter != NULL; todo_id_iter = todo_id_iter->next) {
+    ID *other_id;
+    reference_id = todo_id_iter->data;
+
+    if (reference_id->newid == NULL) {
+      continue;
+    }
+
+    /* Still checking the whole Main, that way we can tag other local IDs as needing to be remapped
+     * to use newly created overriding IDs, if needed. */
+    FOREACH_MAIN_ID_BEGIN (bmain, other_id) {
+      if ((other_id->tag & LIB_TAG_DOIT) != 0 && other_id->lib == NULL) {
+        ID *local_id = reference_id->newid;
+        /* Note that using ID_REMAP_SKIP_INDIRECT_USAGE below is superfluous, as we only remap
+         * local IDs usages anyway... */
+        BKE_libblock_relink_ex(bmain,
+                               other_id,
+                               reference_id,
+                               local_id,
+                               ID_REMAP_SKIP_INDIRECT_USAGE | ID_REMAP_SKIP_OVERRIDE_LIBRARY);
+      }
+    }
+    FOREACH_MAIN_ID_END;
+  }
+
+  BLI_freelistN(&todo_ids);
+
+  return ret;
+}
+
+/* We only build override GHash on request. */
+BLI_INLINE IDOverrideLibraryRuntime *override_library_rna_path_mapping_ensure(
+    IDOverrideLibrary *override)
+{
+  if (override->runtime == NULL) {
+    override->runtime = BLI_ghash_new(BLI_ghashutil_strhash_p, BLI_ghashutil_strcmp, __func__);
+    for (IDOverrideLibraryProperty *op = override->properties.first; op != NULL; op = op->next) {
+      BLI_ghash_insert(override->runtime, op->rna_path, op);
+    }
+  }
+
+  return override->runtime;
+}
+
+/**
+ * Find override property from given RNA path, if it exists.
+ */
+IDOverrideLibraryProperty *BKE_override_library_property_find(IDOverrideLibrary *override,
+                                                              const char *rna_path)
+{
+  IDOverrideLibraryRuntime *override_runtime = override_library_rna_path_mapping_ensure(override);
+  return BLI_ghash_lookup(override_runtime, rna_path);
+}
+
+/**
+ * Find override property from given RNA path, or create it if it does not exist.
+ */
+IDOverrideLibraryProperty *BKE_override_library_property_get(IDOverrideLibrary *override,
+                                                             const char *rna_path,
+                                                             bool *r_created)
+{
+  IDOverrideLibraryProperty *op = BKE_override_library_property_find(override, rna_path);
+
+  if (op == NULL) {
+    op = MEM_callocN(sizeof(IDOverrideLibraryProperty), __func__);
+    op->rna_path = BLI_strdup(rna_path);
+    BLI_addtail(&override->properties, op);
+
+    IDOverrideLibraryRuntime *override_runtime = override_library_rna_path_mapping_ensure(
+        override);
+    BLI_ghash_insert(override_runtime, op->rna_path, op);
+
+    if (r_created) {
+      *r_created = true;
+    }
+  }
+  else if (r_created) {
+    *r_created = false;
+  }
+
+  return op;
+}
+
+void bke_override_property_copy(IDOverrideLibraryProperty *op_dst,
+                                IDOverrideLibraryProperty *op_src)
+{
+  op_dst->rna_path = BLI_strdup(op_src->rna_path);
+  BLI_duplicatelist(&op_dst->operations, &op_src->operations);
+
+  for (IDOverrideLibraryPropertyOperation *opop_dst = op_dst->operations.first,
+                                          *opop_src = op_src->operations.first;
+       opop_dst;
+       opop_dst = opop_dst->next, opop_src = opop_src->next) {
+    bke_override_property_operation_copy(opop_dst, opop_src);
+  }
+}
+
+void bke_override_property_clear(IDOverrideLibraryProperty *op)
+{
+  BLI_assert(op->rna_path != NULL);
+
+  MEM_freeN(op->rna_path);
+
+  for (IDOverrideLibraryPropertyOperation *opop = op->operations.first; opop; opop = opop->next) {
+    bke_override_property_operation_clear(opop);
+  }
+  BLI_freelistN(&op->operations);
+}
+
+/**
+ * Remove and free given \a override_property from given ID \a override.
+ */
+void BKE_override_library_property_delete(IDOverrideLibrary *override,
+                                          IDOverrideLibraryProperty *override_property)
+{
+  bke_override_property_clear(override_property);
+  if (override->runtime != NULL) {
+    BLI_ghash_remove(override->runtime, override_property->rna_path, NULL, NULL);
+  }
+  BLI_freelinkN(&override->properties, override_property);
+}
+
+/**
+ * Find override property operation from given sub-item(s), if it exists.
+ */
+IDOverrideLibraryPropertyOperation *BKE_override_library_property_operation_find(
+    IDOverrideLibraryProperty *override_property,
+    const char *subitem_refname,
+    const char *subitem_locname,
+    const int subitem_refindex,
+    const int subitem_locindex,
+    const bool strict,
+    bool *r_strict)
+{
+  IDOverrideLibraryPropertyOperation *opop;
+  const int subitem_defindex = -1;
+
+  if (r_strict) {
+    *r_strict = true;
+  }
+
+  if (subitem_locname != NULL) {
+    opop = BLI_findstring_ptr(&override_property->operations,
+                              subitem_locname,
+                              offsetof(IDOverrideLibraryPropertyOperation, subitem_local_name));
+
+    if (opop == NULL) {
+      return NULL;
+    }
+
+    if (subitem_refname == NULL || opop->subitem_reference_name == NULL) {
+      return subitem_refname == opop->subitem_reference_name ? opop : NULL;
+    }
+    return (subitem_refname != NULL && opop->subitem_reference_name != NULL &&
+            STREQ(subitem_refname, opop->subitem_reference_name)) ?
+               opop :
+               NULL;
+  }
+
+  if (subitem_refname != NULL) {
+    opop = BLI_findstring_ptr(
+        &override_property->operations,
+        subitem_refname,
+        offsetof(IDOverrideLibraryPropertyOperation, subitem_reference_name));
+
+    if (opop == NULL) {
+      return NULL;
+    }
+
+    if (subitem_locname == NULL || opop->subitem_local_name == NULL) {
+      return subitem_locname == opop->subitem_local_name ? opop : NULL;
+    }
+    return (subitem_locname != NULL && opop->subitem_local_name != NULL &&
+            STREQ(subitem_locname, opop->subitem_local_name)) ?
+               opop :
+               NULL;
+  }
+
+  if ((opop = BLI_listbase_bytes_find(
+           &override_property->operations,
+           &subitem_locindex,
+           sizeof(subitem_locindex),
+           offsetof(IDOverrideLibraryPropertyOperation, subitem_local_index)))) {
+    return ELEM(subitem_refindex, -1, opop->subitem_reference_index) ? opop : NULL;
+  }
+
+  if ((opop = BLI_listbase_bytes_find(
+           &override_property->operations,
+           &subitem_refindex,
+           sizeof(subitem_refindex),
+           offsetof(IDOverrideLibraryPropertyOperation, subitem_reference_index)))) {
+    return ELEM(subitem_locindex, -1, opop->subitem_local_index) ? opop : NULL;
+  }
+
+  /* index == -1 means all indices, that is valid fallback in case we requested specific index. */
+  if (!strict && (subitem_locindex != subitem_defindex) &&
+      (opop = BLI_listbase_bytes_find(
+           &override_property->operations,
+           &subitem_defindex,
+           sizeof(subitem_defindex),
+           offsetof(IDOverrideLibraryPropertyOperation, subitem_local_index)))) {
+    if (r_strict) {
+      *r_strict = false;
+    }
+    return opop;
+  }
+
+  return NULL;
+}
+
+/**
+ * Find override property operation from given sub-item(s), or create it if it does not exist.
+ */
+IDOverrideLibraryPropertyOperation *BKE_override_library_property_operation_get(
+    IDOverrideLibraryProperty *override_property,
+    const short operation,
+    const char *subitem_refname,
+    const char *subitem_locname,
+    const int subitem_refindex,
+    const int subitem_locindex,
+    const bool strict,
+    bool *r_strict,
+    bool *r_created)
+{
+  IDOverrideLibraryPropertyOperation *opop = BKE_override_library_property_operation_find(
+      override_property,
+      subitem_refname,
+      subitem_locname,
+      subitem_refindex,
+      subitem_locindex,
+      strict,
+      r_strict);
+
+  if (opop == NULL) {
+    opop = MEM_callocN(sizeof(IDOverrideLibraryPropertyOperation), __func__);
+    opop->operation = operation;
+    if (subitem_locname) {
+      opop->subitem_local_name = BLI_strdup(subitem_locname);
+    }
+    if (subitem_refname) {
+      opop->subitem_reference_name = BLI_strdup(subitem_refname);
+    }
+    opop->subitem_local_index = subitem_locindex;
+    opop->subitem_reference_index = subitem_refindex;
+
+    BLI_addtail(&override_property->operations, opop);
+
+    if (r_created) {
+      *r_created = true;
+    }
+  }
+  else if (r_created) {
+    *r_created = false;
+  }
+
+  return opop;
+}
+
+void bke_override_property_operation_copy(IDOverrideLibraryPropertyOperation *opop_dst,
+                                          IDOverrideLibraryPropertyOperation *opop_src)
+{
+  if (opop_src->subitem_reference_name) {
+    opop_dst->subitem_reference_name = BLI_strdup(opop_src->subitem_reference_name);
+  }
+  if (opop_src->subitem_local_name) {
+    opop_dst->subitem_local_name = BLI_strdup(opop_src->subitem_local_name);
+  }
+}
+
+void bke_override_property_operation_clear(IDOverrideLibraryPropertyOperation *opop)
+{
+  if (opop->subitem_reference_name) {
+    MEM_freeN(opop->subitem_reference_name);
+  }
+  if (opop->subitem_local_name) {
+    MEM_freeN(opop->subitem_local_name);
+  }
+}
+
+/**
+ * Remove and free given \a override_property_operation from given ID \a override_property.
+ */
+void BKE_override_library_property_operation_delete(
+    IDOverrideLibraryProperty *override_property,
+    IDOverrideLibraryPropertyOperation *override_property_operation)
+{
+  bke_override_property_operation_clear(override_property_operation);
+  BLI_freelinkN(&override_property->operations, override_property_operation);
+}
+
+/**
+ * Check that status of local data-block is still valid against current reference one.
+ *
+ * It means that all overridable, but not overridden, properties' local values must be equal to
+ * reference ones. Clears #LIB_TAG_OVERRIDE_OK if they do not.
+ *
+ * This is typically used to detect whether some property has been changed in local and a new
+ * #IDOverrideProperty (of #IDOverridePropertyOperation) has to be added.
+ *
+ * \return true if status is OK, false otherwise. */
+bool BKE_override_library_status_check_local(Main *bmain, ID *local)
+{
+  BLI_assert(local->override_library != NULL);
+
+  ID *reference = local->override_library->reference;
+
+  if (reference == NULL) {
+    /* This is an override template, local status is always OK! */
+    return true;
+  }
+
+  BLI_assert(GS(local->name) == GS(reference->name));
+
+  if (GS(local->name) == ID_OB) {
+    /* Our beloved pose's bone cross-data pointers... Usually, depsgraph evaluation would ensure
+     * this is valid, but in some cases (like hidden collections etc.) this won't be the case, so
+     * we need to take care of this ourselves. */
+    Object *ob_local = (Object *)local;
+    if (ob_local->data != NULL && ob_local->type == OB_ARMATURE && ob_local->pose != NULL &&
+        ob_local->pose->flag & POSE_RECALC) {
+      BKE_pose_rebuild(bmain, ob_local, ob_local->data, true);
+    }
+  }
+
+  /* Note that reference is assumed always valid, caller has to ensure that itself. */
+
+  PointerRNA rnaptr_local, rnaptr_reference;
+  RNA_id_pointer_create(local, &rnaptr_local);
+  RNA_id_pointer_create(reference, &rnaptr_reference);
+
+  if (!RNA_struct_override_matches(bmain,
+                                   &rnaptr_local,
+                                   &rnaptr_reference,
+                                   NULL,
+                                   local->override_library,
+                                   RNA_OVERRIDE_COMPARE_IGNORE_NON_OVERRIDABLE |
+                                       RNA_OVERRIDE_COMPARE_IGNORE_OVERRIDDEN,
+                                   NULL)) {
+    local->tag &= ~LIB_TAG_OVERRIDE_LIBRARY_REFOK;
+    return false;
+  }
+
+  return true;
+}
+
+/**
+ * Check that status of reference data-block is still valid against current local one.
+ *
+ * It means that all non-overridden properties' local values must be equal to reference ones.
+ * Clears LIB_TAG_OVERRIDE_OK if they do not.
+ *
+ * This is typically used to detect whether some reference has changed and local
+ * needs to be updated against it.
+ *
+ * \return true if status is OK, false otherwise. */
+bool BKE_override_library_status_check_reference(Main *bmain, ID *local)
+{
+  BLI_assert(local->override_library != NULL);
+
+  ID *reference = local->override_library->reference;
+
+  if (reference == NULL) {
+    /* This is an override template, reference is virtual, so its status is always OK! */
+    return true;
+  }
+
+  BLI_assert(GS(local->name) == GS(reference->name));
+
+  if (reference->override_library && (reference->tag & LIB_TAG_OVERRIDE_LIBRARY_REFOK) == 0) {
+    if (!BKE_override_library_status_check_reference(bmain, reference)) {
+      /* If reference is also override of another data-block, and its status is not OK,
+       * then this override is not OK either.
+       * Note that this should only happen when reloading libraries... */
+      local->tag &= ~LIB_TAG_OVERRIDE_LIBRARY_REFOK;
+      return false;
+    }
+  }
+
+  if (GS(local->name) == ID_OB) {
+    /* Our beloved pose's bone cross-data pointers... Usually, depsgraph evaluation would ensure
+     * this is valid, but in some cases (like hidden collections etc.) this won't be the case, so
+     * we need to take care of this ourselves. */
+    Object *ob_local = (Object *)local;
+    if (ob_local->data != NULL && ob_local->type == OB_ARMATURE && ob_local->pose != NULL &&
+        ob_local->pose->flag & POSE_RECALC) {
+      BKE_pose_rebuild(bmain, ob_local, ob_local->data, true);
+    }
+  }
+
+  PointerRNA rnaptr_local, rnaptr_reference;
+  RNA_id_pointer_create(local, &rnaptr_local);
+  RNA_id_pointer_create(reference, &rnaptr_reference);
+
+  if (!RNA_struct_override_matches(bmain,
+                                   &rnaptr_local,
+                                   &rnaptr_reference,
+                                   NULL,
+                                   local->override_library,
+                                   RNA_OVERRIDE_COMPARE_IGNORE_OVERRIDDEN,
+                                   NULL)) {
+    local->tag &= ~LIB_TAG_OVERRIDE_LIBRARY_REFOK;
+    return false;
+  }
+
+  return true;
+}
+
+/**
+ * Compares local and reference data-blocks and create new override operations as needed,
+ * or reset to reference values if overriding is not allowed.
+ *
+ * \note Defining override operations is only mandatory before saving a `.blend` file on disk
+ * (not for undo!).
+ * Knowing that info at runtime is only useful for UI/UX feedback.
+ *
+ * \note This is by far the biggest operation (the more time-consuming) of the three so far,
+ * since it has to go over all properties in depth (all overridable ones at least).
+ * Generating diff values and applying overrides are much cheaper.
+ *
+ * \return true if new overriding op was created, or some local data was reset. */
+bool BKE_override_library_operations_create(Main *bmain, ID *local, const bool force_auto)
+{
+  BLI_assert(local->override_library != NULL);
+  const bool is_template = (local->override_library->reference == NULL);
+  bool ret = false;
+
+  if (!is_template && (force_auto || local->override_library->flag & OVERRIDE_LIBRARY_AUTO)) {
+    /* Do not attempt to generate overriding rules from an empty place-holder generated by link
+     * code when it cannot find to actual library/ID. Much better to keep the local datablock as
+     * is in the file in that case, until broken lib is fixed. */
+    if (ID_MISSING(local->override_library->reference)) {
+      return ret;
+    }
+
+    if (GS(local->name) == ID_OB) {
+      /* Our beloved pose's bone cross-data pointers... Usually, depsgraph evaluation would ensure
+       * this is valid, but in some cases (like hidden collections etc.) this won't be the case, so
+       * we need to take care of this ourselves. */
+      Object *ob_local = (Object *)local;
+      if (ob_local->data != NULL && ob_local->type == OB_ARMATURE && ob_local->pose != NULL &&
+          ob_local->pose->flag & POSE_RECALC) {
+        BKE_pose_rebuild(bmain, ob_local, ob_local->data, true);
+      }
+    }
+
+    PointerRNA rnaptr_local, rnaptr_reference;
+    RNA_id_pointer_create(local, &rnaptr_local);
+    RNA_id_pointer_create(local->override_library->reference, &rnaptr_reference);
+
+    eRNAOverrideMatchResult report_flags = 0;
+    RNA_struct_override_matches(bmain,
+                                &rnaptr_local,
+                                &rnaptr_reference,
+                                NULL,
+                                local->override_library,
+                                RNA_OVERRIDE_COMPARE_CREATE | RNA_OVERRIDE_COMPARE_RESTORE,
+                                &report_flags);
+    if (report_flags & RNA_OVERRIDE_MATCH_RESULT_CREATED) {
+      ret = true;
+    }
+#ifndef NDEBUG
+    if (report_flags & RNA_OVERRIDE_MATCH_RESULT_RESTORED) {
+      printf("We did restore some properties of %s from its reference.\n", local->name);
+    }
+    if (ret) {
+      printf("We did generate library override rules for %s\n", local->name);
+    }
+    else {
+      printf("No new library override rules for %s\n", local->name);
+    }
+#endif
+  }
+  return ret;
+}
+
+/** Check all overrides from given \a bmain and create/update overriding operations as needed. */
+void BKE_main_override_library_operations_create(Main *bmain, const bool force_auto)
+{
+  ID *id;
+
+  FOREACH_MAIN_ID_BEGIN (bmain, id) {
+    if ((ID_IS_OVERRIDE_LIBRARY(id) && force_auto) ||
+        (ID_IS_OVERRIDE_LIBRARY_AUTO(id) && (id->tag & LIB_TAG_OVERRIDE_LIBRARY_AUTOREFRESH))) {
+      BKE_override_library_operations_create(bmain, id, force_auto);
+      id->tag &= ~LIB_TAG_OVERRIDE_LIBRARY_AUTOREFRESH;
+    }
+  }
+  FOREACH_MAIN_ID_END;
+}
+
+/** Update given override from its reference (re-applying overridden properties). */
+void BKE_override_library_update(Main *bmain, ID *local)
+{
+  if (local->override_library == NULL || local->override_library->reference == NULL) {
+    return;
+  }
+
+  /* Do not attempt to apply overriding rules over an empty place-holder generated by link code
+   * when it cannot find to actual library/ID. Much better to keep the local datablock as loaded
+   * from the file in that case, until broken lib is fixed. */
+  if (ID_MISSING(local->override_library->reference)) {
+    return;
+  }
+
+  /* Recursively do 'ancestors' overrides first, if any. */
+  if (local->override_library->reference->override_library &&
+      (local->override_library->reference->tag & LIB_TAG_OVERRIDE_LIBRARY_REFOK) == 0) {
+    BKE_override_library_update(bmain, local->override_library->reference);
+  }
+
+  /* We want to avoid having to remap here, however creating up-to-date override is much simpler
+   * if based on reference than on current override.
+   * So we work on temp copy of reference, and 'swap' its content with local. */
+
+  /* XXX We need a way to get off-Main copies of IDs (similar to localized mats/texts/ etc.)!
+   *     However, this is whole bunch of code work in itself, so for now plain stupid ID copy will
+   *     do, as inn-efficient as it is. :/
+   *     Actually, maybe not! Since we are swapping with original ID's local content, we want to
+   *     keep user-count in correct state when freeing tmp_id
+   *     (and that user-counts of IDs used by 'new' local data also remain correct). */
+  /* This would imply change in handling of user-count all over RNA
+   * (and possibly all over Blender code).
+   * Not impossible to do, but would rather see first if extra useless usual user handling
+   * is actually a (performances) issue here. */
+
+  ID *tmp_id;
+  BKE_id_copy(bmain, local->override_library->reference, &tmp_id);
+
+  if (tmp_id == NULL) {
+    return;
+  }
+
+  PointerRNA rnaptr_src, rnaptr_dst, rnaptr_storage_stack, *rnaptr_storage = NULL;
+  RNA_id_pointer_create(local, &rnaptr_src);
+  RNA_id_pointer_create(tmp_id, &rnaptr_dst);
+  if (local->override_library->storage) {
+    rnaptr_storage = &rnaptr_storage_stack;
+    RNA_id_pointer_create(local->override_library->storage, rnaptr_storage);
+  }
+
+  RNA_struct_override_apply(
+      bmain, &rnaptr_dst, &rnaptr_src, rnaptr_storage, local->override_library);
+
+  /* This also transfers all pointers (memory) owned by local to tmp_id, and vice-versa.
+   * So when we'll free tmp_id, we'll actually free old, outdated data from local. */
+  BKE_id_swap(bmain, local, tmp_id);
+
+  /* Again, horribly inn-efficient in our case, we need something off-Main
+   * (aka more generic nolib copy/free stuff)! */
+  /* XXX And crashing in complex cases (e.g. because depsgraph uses same data...). */
+  BKE_id_free_ex(bmain, tmp_id, LIB_ID_FREE_NO_UI_USER, true);
+
+  if (local->override_library->storage) {
+    /* We know this datablock is not used anywhere besides local->override->storage. */
+    /* XXX For until we get fully shadow copies, we still need to ensure storage releases
+     *     its usage of any ID pointers it may have. */
+    BKE_id_free_ex(bmain, local->override_library->storage, LIB_ID_FREE_NO_UI_USER, true);
+    local->override_library->storage = NULL;
+  }
+
+  local->tag |= LIB_TAG_OVERRIDE_LIBRARY_REFOK;
+
+  /* Full rebuild of Depsgraph! */
+
+  /* XXX Is this actual valid replacement for old DAG_relations_tag_update(bmain) ? */
+  DEG_on_visible_update(bmain, true);
+}
+
+/** Update all overrides from given \a bmain. */
+void BKE_main_override_library_update(Main *bmain)
+{
+  ID *id;
+
+  FOREACH_MAIN_ID_BEGIN (bmain, id) {
+    if (id->override_library != NULL && id->lib == NULL) {
+      BKE_override_library_update(bmain, id);
+    }
+  }
+  FOREACH_MAIN_ID_END;
+}
+
+/**
+ * Storage (how to store overriding data into `.blend` files).
+ *
+ * Basically:
+ * 1) Only 'differential' storage needs special handling here. All others (replacing values or
+ *    inserting/removing items from a collection) can be handled with simply storing current
+ *    content of local data-block.
+ * 2) We store the differential value into a second 'ghost' data-block,
+ *    which is an empty ID of same type as local one,
+ *    where we only define values that need differential data.
+ *
+ * This avoids us having to modify 'real' data-block at write time (and restoring it afterwards),
+ * which is inefficient, and potentially dangerous (in case of concurrent access...), while not
+ * using much extra memory in typical cases.  It also ensures stored data-block always contains
+ * exact same data as "desired" ones (kind of "baked" data-blocks).
+ */
+
+/** Initialize an override storage. */
+OverrideLibraryStorage *BKE_override_library_operations_store_initialize(void)
+{
+  return BKE_main_new();
+}
+
+/**
+ * Generate suitable 'write' data (this only affects differential override operations).
+ *
+ * Note that \a local ID is no more modified by this call,
+ * all extra data are stored in its temp \a storage_id copy. */
+ID *BKE_override_library_operations_store_start(Main *bmain,
+                                                OverrideLibraryStorage *override_storage,
+                                                ID *local)
+{
+  BLI_assert(local->override_library != NULL);
+  BLI_assert(override_storage != NULL);
+  const bool is_template = (local->override_library->reference == NULL);
+
+  if (is_template) {
+    /* This is actually purely local data with an override template, nothing to do here! */
+    return NULL;
+  }
+
+  /* Forcefully ensure we know about all needed override operations. */
+  BKE_override_library_operations_create(bmain, local, false);
+
+  ID *storage_id;
+#ifdef DEBUG_OVERRIDE_TIMEIT
+  TIMEIT_START_AVERAGED(BKE_override_operations_store_start);
+#endif
+
+  /* XXX TODO We may also want a specialized handling of things here too, to avoid copying heavy
+   * never-overridable data (like Mesh geometry etc.)? And also maybe avoid lib reference-counting
+   * completely (shallow copy...). */
+  /* This would imply change in handling of user-count all over RNA
+   * (and possibly all over Blender code).
+   * Not impossible to do, but would rather see first is extra useless usual user handling is
+   * actually a (performances) issue here, before doing it. */
+  BKE_id_copy((Main *)override_storage, local, &storage_id);
+
+  if (storage_id != NULL) {
+    PointerRNA rnaptr_reference, rnaptr_final, rnaptr_storage;
+    RNA_id_pointer_create(local->override_library->reference, &rnaptr_reference);
+    RNA_id_pointer_create(local, &rnaptr_final);
+    RNA_id_pointer_create(storage_id, &rnaptr_storage);
+
+    if (!RNA_struct_override_store(
+            bmain, &rnaptr_final, &rnaptr_reference, &rnaptr_storage, local->override_library)) {
+      BKE_id_free_ex(override_storage, storage_id, LIB_ID_FREE_NO_UI_USER, true);
+      storage_id = NULL;
+    }
+  }
+
+  local->override_library->storage = storage_id;
+
+#ifdef DEBUG_OVERRIDE_TIMEIT
+  TIMEIT_END_AVERAGED(BKE_override_operations_store_start);
+#endif
+  return storage_id;
+}
+
+/** Restore given ID modified by \a BKE_override_operations_store_start, to its original state. */
+void BKE_override_library_operations_store_end(OverrideLibraryStorage *UNUSED(override_storage),
+                                               ID *local)
+{
+  BLI_assert(local->override_library != NULL);
+
+  /* Nothing else to do here really, we need to keep all temp override storage data-blocks in
+   * memory until whole file is written anyway (otherwise we'd get mem pointers overlap...). */
+  local->override_library->storage = NULL;
+}
+
+void BKE_override_library_operations_store_finalize(OverrideLibraryStorage *override_storage)
+{
+  /* We cannot just call BKE_main_free(override_storage), not until we have option to make 'ghost'
+   * copies of IDs without increasing usercount of used data-blocks. */
+  ID *id;
+
+  FOREACH_MAIN_ID_BEGIN (override_storage, id) {
+    BKE_id_free_ex(override_storage, id, LIB_ID_FREE_NO_UI_USER, true);
+  }
+  FOREACH_MAIN_ID_END;
+
+  BKE_main_free(override_storage);
+}