blender-archive/source/blender/blenkernel/intern/library_override.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) 2016 by Blender Foundation.
 * All rights reserved.
 */

/** \file blender/blenkernel/intern/library_override.c
 *  \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_library.h"
#include "BKE_library_override.h"
#include "BKE_library_remap.h"
#include "BKE_main.h"

#include "BLI_utildefines.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(IDOverrideStaticProperty *op_dst, IDOverrideStaticProperty *op_src);
static void bke_override_property_operation_copy(IDOverrideStaticPropertyOperation *opop_dst, IDOverrideStaticPropertyOperation *opop_src);

static void bke_override_property_clear(IDOverrideStaticProperty *op);
static void bke_override_property_operation_clear(IDOverrideStaticPropertyOperation *opop);

/* Temp, for until static override is ready and tested enough to go 'public', we hide it by default in UI and such. */
static bool _override_static_enabled = false;

void BKE_override_static_enable(const bool do_enable)
{
	_override_static_enabled = do_enable;
}

bool BKE_override_static_is_enabled()
{
	return _override_static_enabled;
}

/** Initialize empty overriding of \a reference_id by \a local_id. */
IDOverrideStatic *BKE_override_static_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_static == NULL);

	ID *ancestor_id;
	for (ancestor_id = reference_id;
	     ancestor_id != NULL && ancestor_id->override_static != NULL && ancestor_id->override_static->reference != NULL;
	     ancestor_id = ancestor_id->override_static->reference);

	if (ancestor_id != NULL && ancestor_id->override_static != NULL) {
		/* Original ID has a template, use it! */
		BKE_override_static_copy(local_id, ancestor_id);
		if (local_id->override_static->reference != reference_id) {
			id_us_min(local_id->override_static->reference);
			local_id->override_static->reference = reference_id;
			id_us_plus(local_id->override_static->reference);
		}
		return local_id->override_static;
	}

	/* Else, generate new empty override. */
	local_id->override_static = MEM_callocN(sizeof(*local_id->override_static), __func__);
	local_id->override_static->reference = reference_id;
	id_us_plus(local_id->override_static->reference);
	local_id->tag &= ~LIB_TAG_OVERRIDESTATIC_REFOK;
	/* TODO do we want to add tag or flag to referee to mark it as such? */
	return local_id->override_static;
}

/** Deep copy of a whole override from \a src_id to \a dst_id. */
void BKE_override_static_copy(ID *dst_id, const ID *src_id)
{
	BLI_assert(src_id->override_static != NULL);

	if (dst_id->override_static != NULL) {
		if (src_id->override_static == NULL) {
			BKE_override_static_free(&dst_id->override_static);
			return;
		}
		else {
			BKE_override_static_clear(dst_id->override_static);
		}
	}
	else if (src_id->override_static == NULL) {
		return;
	}
	else {
		BKE_override_static_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_static->reference = src_id->override_static->reference ? src_id->override_static->reference : (ID *)src_id;
	id_us_plus(dst_id->override_static->reference);

	BLI_duplicatelist(&dst_id->override_static->properties, &src_id->override_static->properties);
	for (IDOverrideStaticProperty *op_dst = dst_id->override_static->properties.first, *op_src = src_id->override_static->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_OVERRIDESTATIC_REFOK;
}

/** Clear any overriding data from given \a override. */
void BKE_override_static_clear(IDOverrideStatic *override)
{
	BLI_assert(override != NULL);

	for (IDOverrideStaticProperty *op = override->properties.first; op; op = op->next) {
		bke_override_property_clear(op);
	}
	BLI_freelistN(&override->properties);

	id_us_min(override->reference);
	/* override->storage should never be refcounted... */
}

/** Free given \a override. */
void BKE_override_static_free(struct IDOverrideStatic **override)
{
	BLI_assert(*override != NULL);

	BKE_override_static_clear(*override);
	MEM_freeN(*override);
	*override = NULL;
}

static ID *override_static_create_from(Main *bmain, ID *reference_id)
{
	ID *local_id;

	if (!id_copy(bmain, reference_id, (ID **)&local_id)) {
		return NULL;
	}
	id_us_min(local_id);

	BKE_override_static_init(local_id, reference_id);
	local_id->override_static->flag |= STATICOVERRIDE_AUTO;

	return local_id;
}


/** Create an overridden local copy of linked reference. */
ID *BKE_override_static_create_from_id(Main *bmain, ID *reference_id)
{
	BLI_assert(reference_id != NULL);
	BLI_assert(reference_id->lib != NULL);

	ID *local_id = override_static_create_from(bmain, reference_id);

	/* Remapping, we obviously only want to affect local data (and not our own reference pointer to overridden ID). */
	BKE_libblock_remap(bmain, reference_id, local_id, ID_REMAP_SKIP_INDIRECT_USAGE | ID_REMAP_SKIP_STATIC_OVERRIDE);

	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.
 *
 * \return \a true on success, \a false otherwise.
 */
bool BKE_override_static_create_from_tag(Main *bmain)
{
	ListBase *lbarray[MAX_LIBARRAY];
	int a;
	bool ret = true;

	const int num_types = a = set_listbasepointers(bmain, lbarray);
	while (a--) {
		for (ID *reference_id = lbarray[a]->first; reference_id != NULL; reference_id = reference_id->next) {
			if ((reference_id->tag & LIB_TAG_DOIT) != 0 && reference_id->lib != NULL) {
				if ((reference_id->newid = override_static_create_from(bmain, reference_id)) == NULL) {
					ret = false;
				}
			}
		}
	}

	/* Remapping, we obviously only want to affect local data (and not our own reference pointer to overridden ID). */
	a = num_types;
	while (a--) {
		for (ID *reference_id = lbarray[a]->first; reference_id != NULL; reference_id = reference_id->next) {
			if ((reference_id->tag & LIB_TAG_DOIT) != 0 && reference_id->lib != NULL && reference_id->newid != NULL) {
				ID *local_id = reference_id->newid;
				BKE_libblock_remap(bmain, reference_id, local_id,
				                   ID_REMAP_SKIP_INDIRECT_USAGE | ID_REMAP_SKIP_STATIC_OVERRIDE);
			}
		}
	}

	return ret;
}

/**
 * Find override property from given RNA path, if it exists.
 */
IDOverrideStaticProperty *BKE_override_static_property_find(IDOverrideStatic *override, const char *rna_path)
{
	/* XXX TODO we'll most likely want a runtime ghash to store that mapping at some point. */
	return BLI_findstring_ptr(&override->properties, rna_path, offsetof(IDOverrideStaticProperty, rna_path));
}

/**
 * Find override property from given RNA path, or create it if it does not exist.
 */
IDOverrideStaticProperty *BKE_override_static_property_get(IDOverrideStatic *override, const char *rna_path, bool *r_created)
{
	/* XXX TODO we'll most likely want a runtime ghash to store that mapping at some point. */
	IDOverrideStaticProperty *op = BKE_override_static_property_find(override, rna_path);

	if (op == NULL) {
		op = MEM_callocN(sizeof(IDOverrideStaticProperty), __func__);
		op->rna_path = BLI_strdup(rna_path);
		BLI_addtail(&override->properties, op);

		if (r_created) {
			*r_created = true;
		}
	}
	else if (r_created) {
		*r_created = false;
	}

	return op;
}

void bke_override_property_copy(IDOverrideStaticProperty *op_dst, IDOverrideStaticProperty *op_src)
{
	op_dst->rna_path = BLI_strdup(op_src->rna_path);
	BLI_duplicatelist(&op_dst->operations, &op_src->operations);

	for (IDOverrideStaticPropertyOperation *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(IDOverrideStaticProperty *op)
{
	BLI_assert(op->rna_path != NULL);

	MEM_freeN(op->rna_path);

	for (IDOverrideStaticPropertyOperation *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_static_property_delete(IDOverrideStatic *override, IDOverrideStaticProperty *override_property)
{
	bke_override_property_clear(override_property);
	BLI_freelinkN(&override->properties, override_property);
}

/**
 * Find override property operation from given sub-item(s), if it exists.
 */
IDOverrideStaticPropertyOperation *BKE_override_static_property_operation_find(
        IDOverrideStaticProperty *override_property,
        const char *subitem_refname, const char *subitem_locname,
        const int subitem_refindex, const int subitem_locindex, const bool strict, bool *r_strict)
{
	IDOverrideStaticPropertyOperation *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(IDOverrideStaticPropertyOperation, 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(IDOverrideStaticPropertyOperation, 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(IDOverrideStaticPropertyOperation, 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(IDOverrideStaticPropertyOperation, 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(IDOverrideStaticPropertyOperation, 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.
 */
IDOverrideStaticPropertyOperation *BKE_override_static_property_operation_get(
        IDOverrideStaticProperty *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)
{
	IDOverrideStaticPropertyOperation *opop = BKE_override_static_property_operation_find(override_property,
	                                                                         subitem_refname, subitem_locname,
	                                                                         subitem_refindex, subitem_locindex,
	                                                                         strict, r_strict);

	if (opop == NULL) {
		opop = MEM_callocN(sizeof(IDOverrideStaticPropertyOperation), __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(IDOverrideStaticPropertyOperation *opop_dst, IDOverrideStaticPropertyOperation *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(IDOverrideStaticPropertyOperation *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_static_property_operation_delete(
        IDOverrideStaticProperty *override_property, IDOverrideStaticPropertyOperation *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_static_status_check_local(Main *bmain, ID *local)
{
	BLI_assert(local->override_static != NULL);

	ID *reference = local->override_static->reference;

	if (reference == NULL) {
		/* This is an override template, local status is always OK! */
		return true;
	}

	BLI_assert(GS(local->name) == GS(reference->name));

	/* 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_static,
	        RNA_OVERRIDE_COMPARE_IGNORE_NON_OVERRIDABLE | RNA_OVERRIDE_COMPARE_IGNORE_OVERRIDDEN, NULL))
	{
		local->tag &= ~LIB_TAG_OVERRIDESTATIC_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_static_status_check_reference(Main *bmain, ID *local)
{
	BLI_assert(local->override_static != NULL);

	ID *reference = local->override_static->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_static && (reference->tag & LIB_TAG_OVERRIDESTATIC_REFOK) == 0) {
		if (!BKE_override_static_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_OVERRIDESTATIC_REFOK;
			return false;
		}
	}

	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_static,
	        RNA_OVERRIDE_COMPARE_IGNORE_OVERRIDDEN, NULL))
	{
		local->tag &= ~LIB_TAG_OVERRIDESTATIC_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_static_operations_create(Main *bmain, ID *local, const bool force_auto)
{
	BLI_assert(local->override_static != NULL);
	const bool is_template = (local->override_static->reference == NULL);
	bool ret = false;

	if (!is_template && (force_auto || local->override_static->flag & STATICOVERRIDE_AUTO)) {
		PointerRNA rnaptr_local, rnaptr_reference;
		RNA_id_pointer_create(local, &rnaptr_local);
		RNA_id_pointer_create(local->override_static->reference, &rnaptr_reference);

		eRNAOverrideMatchResult report_flags = 0;
		RNA_struct_override_matches(
		            bmain,
		            &rnaptr_local, &rnaptr_reference, NULL, local->override_static,
		            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 static override rules for %s\n", local->name);
		}
		else {
			printf("No new static 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_static_operations_create(Main *bmain, const bool force_auto)
{
	ListBase *lbarray[MAX_LIBARRAY];
	int base_count, i;

	base_count = set_listbasepointers(bmain, lbarray);

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

		for (id = lb->first; id; id = id->next) {
			if (force_auto ||
			    (ID_IS_STATIC_OVERRIDE_AUTO(id) && (id->tag & LIB_TAG_OVERRIDESTATIC_AUTOREFRESH)))
			{
				BKE_override_static_operations_create(bmain, id, force_auto);
				id->tag &= ~LIB_TAG_OVERRIDESTATIC_AUTOREFRESH;
			}
		}
	}
}

/** Update given override from its reference (re-applying overridden properties). */
void BKE_override_static_update(Main *bmain, ID *local)
{
	if (local->override_static == NULL || local->override_static->reference == NULL) {
		return;
	}

	/* Recursively do 'ancestors' overrides first, if any. */
	if (local->override_static->reference->override_static && (local->override_static->reference->tag & LIB_TAG_OVERRIDESTATIC_REFOK) == 0) {
		BKE_override_static_update(bmain, local->override_static->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 innefficient as it is. :/
	 *     Actually, maybe not! Since we are swapping with original ID's local content, we want to keep
	 *     usercount in correct state when freeing tmp_id (and that usercounts of IDs used by 'new' local data
	 *     also remain correct). */
	/* This would imply change in handling of usercout 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;
	id_copy(bmain, local->override_static->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_static->storage) {
		rnaptr_storage = &rnaptr_storage_stack;
		RNA_id_pointer_create(local->override_static->storage, rnaptr_storage);
	}

	RNA_struct_override_apply(bmain, &rnaptr_dst, &rnaptr_src, rnaptr_storage, local->override_static);

	/* 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 innefficient in our case, we need something off-Main (aka moar 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_static->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_static->storage, LIB_ID_FREE_NO_UI_USER, true);
		local->override_static->storage = NULL;
	}

	local->tag |= LIB_TAG_OVERRIDESTATIC_REFOK;

	/* Full rebuild of Depsgraph! */
	DEG_on_visible_update(bmain, true);  /* XXX Is this actual valid replacement for old DAG_relations_tag_update(bmain) ? */
}

/** Update all overrides from given \a bmain. */
void BKE_main_override_static_update(Main *bmain)
{
	ListBase *lbarray[MAX_LIBARRAY];
	int base_count, i;

	base_count = set_listbasepointers(bmain, 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_static != NULL && id->lib == NULL) {
				BKE_override_static_update(bmain, id);
			}
		}
	}
}

/***********************************************************************************************************************
 * Storage (how to wtore overriding data into .blend files).
 *
 * Basically:
 * I) 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.
 * II) 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 inneficient,
 * 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. */
OverrideStaticStorage *BKE_override_static_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_static_operations_store_start(Main *bmain, OverrideStaticStorage *override_storage, ID *local)
{
	BLI_assert(local->override_static != NULL);
	BLI_assert(override_storage != NULL);
	const bool is_template = (local->override_static->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_static_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 refcounting completely (shallow copy...). */
	/* This would imply change in handling of usercout 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. */
	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_static->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_static))
		{
			BKE_id_free_ex(override_storage, storage_id, LIB_ID_FREE_NO_UI_USER, true);
			storage_id = NULL;
		}
	}

	local->override_static->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_static_operations_store_end(OverrideStaticStorage *UNUSED(override_storage), ID *local)
{
	BLI_assert(local->override_static != 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_static->storage = NULL;
}

void BKE_override_static_operations_store_finalize(OverrideStaticStorage *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... */
	ListBase *lbarray[MAX_LIBARRAY];
	int base_count, i;

	base_count = set_listbasepointers(override_storage, lbarray);

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

		while ((id = lb->first)) {
			BKE_id_free_ex(override_storage, id, LIB_ID_FREE_NO_UI_USER, true);
		}
	}

	BKE_main_free(override_storage);
}