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diff --git a/source/blender/depsgraph/intern/eval/deg_eval_copy_on_write.h b/source/blender/depsgraph/intern/eval/deg_eval_copy_on_write.h
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+/*
+ * ***** BEGIN GPL LICENSE BLOCK *****
+ *
+ * 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) 20137Blender Foundation.
+ * All rights reserved.
+ *
+ * Original Author: Sergey Sharybin
+ * Contributor(s): None Yet
+ *
+ * ***** END GPL LICENSE BLOCK *****
+ */
+
+/** \file blender/depsgraph/intern/eval/deg_eval_copy_on_write.h
+ *  \ingroup depsgraph
+ */
+
+#pragma once
+
+#include <stddef.h>
+
+struct EvaluationContext;
+struct ID;
+
+/* Unkomment this to have verbose log about original and CoW pointers
+ * logged, with detailed information when they are allocated, expanded
+ * and remapped.
+ */
+// #define DEG_DEBUG_COW_POINTERS
+
+#ifdef DEG_DEBUG_COW_POINTERS
+#  define DEG_COW_PRINT(format, ...) printf(format, __VA_ARGS__);
+#else
+#  define DEG_COW_PRINT(format, ...)
+#endif
+
+namespace DEG {
+
+struct Depsgraph;
+struct DepsgraphNodeBuilder;
+struct IDDepsNode;
+
+/* Get fully expanded (ready for use) copy-on-write datablock for the given
+ * original datablock.
+ */
+ID *deg_expand_copy_on_write_datablock(const struct Depsgraph *depsgraph,
+                                       const IDDepsNode *id_node,
+                                       DepsgraphNodeBuilder *node_builder = NULL,
+                                       bool create_placeholders = false);
+ID *deg_expand_copy_on_write_datablock(const struct Depsgraph *depsgraph,
+                                       struct ID *id_orig,
+                                       DepsgraphNodeBuilder *node_builder = NULL,
+                                       bool create_placeholders = false);
+
+/* Makes sure given CoW datablock is brought back to state of the original
+ * datablock.
+ */
+ID *deg_update_copy_on_write_datablock(const struct Depsgraph *depsgraph,
+                                       const IDDepsNode *id_node);
+ID *deg_update_copy_on_write_datablock(const struct Depsgraph *depsgraph,
+                                       struct ID *id_orig);
+
+/* Helper function which frees memory used by copy-on-written databnlock. */
+void deg_free_copy_on_write_datablock(struct ID *id_cow);
+
+/* Callback function for depsgraph operation node which ensures copy-on-write
+ * datablock is ready for use by further evaluation routines.
+ */
+void deg_evaluate_copy_on_write(const struct EvaluationContext *eval_ctx,
+                                const struct Depsgraph *depsgraph,
+                                const struct IDDepsNode *id_node);
+
+/* Check that given ID is propely expanded and does not have any shallow
+ * copies inside.
+  */
+bool deg_validate_copy_on_write_datablock(ID *id_cow);
+
+/* Tag given ID block as being copy-on-wtritten. */
+void deg_tag_copy_on_write_id(struct ID *id_cow, const struct ID *id_orig);
+
+/* Check whether ID datablock is expanded.
+ *
+ * TODO(sergey): Make it an inline function or a macro.
+ */
+bool deg_copy_on_write_is_expanded(const struct ID *id_cow);
+
+/* Check whether copy-on-write datablock is needed for given ID.
+ *
+ * There are some exceptions on datablocks which are covered by dependency graph
+ * but which we don't want to start duplicating.
+ *
+ * This includes images.
+ */
+bool deg_copy_on_write_is_needed(const ID *id_orig);
+
+}  // namespace DEG