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, 8 deletions

diff --git a/source/blender/windowmanager/intern/wm_files.c b/source/blender/windowmanager/intern/wm_files.c
index e0b57effbe9..1d96d291dc4 100644
--- a/source/blender/windowmanager/intern/wm_files.c
+++ b/source/blender/windowmanager/intern/wm_files.c
@@ -87,9 +87,11 @@
 #include "BKE_sound.h"
 #include "BKE_scene.h"
 #include "BKE_screen.h"
+#include "BKE_undo_system.h"
 
 #include "BLO_readfile.h"
 #include "BLO_writefile.h"
+#include "BLO_undofile.h"  /* to save from an undo memfile */
 
 #include "RNA_access.h"
 #include "RNA_define.h"
@@ -522,9 +524,13 @@ static void wm_file_read_post(bContext *C, const bool is_startup_file, const boo
 	}
 
 	if (!G.background) {
-//		undo_editmode_clear();
-		BKE_undo_reset();
-		BKE_undo_write(C, "original");  /* save current state */
+		if (wm->undo_stack == NULL) {
+			wm->undo_stack = BKE_undosys_stack_create();
+		}
+		else {
+			BKE_undosys_stack_clear(wm->undo_stack);
+		}
+		BKE_undosys_stack_init_from_main(wm->undo_stack, CTX_data_main(C));
 	}
 }
 
@@ -596,10 +602,6 @@ bool WM_file_read(bContext *C, const char *filepath, ReportList *reports)
 
 		success = true;
 	}
-#if 0
-	else if (retval == BKE_READ_EXOTIC_OK_OTHER)
-		BKE_undo_write(C, "Import file");
-#endif
 	else if (retval == BKE_READ_EXOTIC_FAIL_OPEN) {
 		BKE_reportf(reports, RPT_ERROR, "Cannot read file '%s': %s", filepath,
 		            errno ? strerror(errno) : TIP_("unable to open the file"));
@@ -1271,7 +1273,10 @@ void wm_autosave_timer(const bContext *C, wmWindowManager *wm, wmTimer *UNUSED(w
 
 	if (U.uiflag & USER_GLOBALUNDO) {
 		/* fast save of last undobuffer, now with UI */
-		BKE_undo_save_file(filepath);
+		struct MemFile *memfile = ED_undosys_stack_memfile_get_active(wm->undo_stack);
+		if (memfile) {
+			BLO_memfile_write_file(memfile, filepath);
+		}
 	}
 	else {
 		/*  save as regular blend file */