Undo: unified undo system w/ linear history

- Use a single undo history for all operations.
- UndoType's are registered and poll the context to check if they
  should be used when performing an undo push.
- Mode switching is used to ensure the state is correct before
  undo data is restored.
- Some undo types accumulate changes (image & text editing)
  others store the state multiple times (with de-duplication).
  This is supported by checking UndoStack.mode `ACCUMULATE` / `STORE`.
- Each undo step stores ID datablocks they use with utilities to help
  manage restoring correct ID's.
  Needed since global undo is now mixed with other modes undo.
- Currently performs each undo step when going up/down history
  Previously this wasn't done, making history fail in some cases.
  This can be optimized to skip some combinations of undo steps.

grease-pencil is an exception which has not been updated
since it integrates undo into the draw-session.

See D3113

1 files changed, 4 insertions, 13 deletions

diff --git a/source/blender/blenkernel/BKE_blender_undo.h b/source/blender/blenkernel/BKE_blender_undo.h
index 84a6d07be7d..a96f8af1fdb 100644
--- a/source/blender/blenkernel/BKE_blender_undo.h
+++ b/source/blender/blenkernel/BKE_blender_undo.h
@@ -31,22 +31,13 @@ extern "C" {
 struct bContext;
 struct Scene;
 struct Main;
+struct MemFileUndoData;
 
 #define BKE_UNDO_STR_MAX 64
 
-/* global undo */
-extern void          BKE_undo_write(struct bContext *C, const char *name);
-extern void          BKE_undo_step(struct bContext *C, int step);
-extern void          BKE_undo_name(struct bContext *C, const char *name);
-extern bool          BKE_undo_is_valid(const char *name);
-extern void          BKE_undo_reset(void);
-extern void          BKE_undo_number(struct bContext *C, int nr);
-extern const char   *BKE_undo_get_name(int nr, bool *r_active);
-extern const char   *BKE_undo_get_name_last(void);
-extern bool          BKE_undo_save_file(const char *filename);
-extern struct Main  *BKE_undo_get_main(struct Scene **r_scene);
-
-extern void          BKE_undo_callback_wm_kill_jobs_set(void (*callback)(struct bContext *C));
+struct MemFileUndoData *BKE_memfile_undo_encode(struct Main *bmain, struct MemFileUndoData *mfu_prev);
+bool                    BKE_memfile_undo_decode(struct MemFileUndoData *mfu, struct bContext *C);
+void                    BKE_memfile_undo_free(struct MemFileUndoData *mfu);
 
 #ifdef __cplusplus
 }