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, 13 insertions, 1 deletions

diff --git a/source/blender/blenloader/BLO_undofile.h b/source/blender/blenloader/BLO_undofile.h
index d3c0130a63b..b713b963056 100644
--- a/source/blender/blenloader/BLO_undofile.h
+++ b/source/blender/blenloader/BLO_undofile.h
@@ -33,6 +33,8 @@
  *  \ingroup blenloader
  */
 
+struct Scene;
+
 typedef struct {
 	void *next, *prev;
 	const char *buf;
@@ -47,6 +49,12 @@ typedef struct MemFile {
 	size_t size;
 } MemFile;
 
+typedef struct MemFileUndoData {
+	char filename[1024];  /* FILE_MAX */
+	MemFile memfile;
+	size_t undo_size;
+} MemFileUndoData;
+
 /* actually only used writefile.c */
 extern void memfile_chunk_add(MemFile *compare, MemFile *current, const char *buf, unsigned int size);
 
@@ -54,5 +62,9 @@ extern void memfile_chunk_add(MemFile *compare, MemFile *current, const char *bu
 extern void BLO_memfile_free(MemFile *memfile);
 extern void BLO_memfile_merge(MemFile *first, MemFile *second);
 
-#endif
+/* utilities */
+extern struct Main *BLO_memfile_main_get(struct MemFile *memfile, struct Main *bmain, struct Scene **r_scene);
+extern bool BLO_memfile_write_file(struct MemFile *memfile, const char *filename);
+
+#endif  /* __BLO_UNDOFILE_H__ */