Bugfix #25570

The tool-redo depends on a working undo system, so it can rewind
a step and then redo operator with new settings. When a user
disables undo, this won't work.

Now the properties for redo operator (toolbar, F6) will grey out
when a redo isn't possible.

3 files changed, 61 insertions, 0 deletions

diff --git a/source/blender/editors/util/editmode_undo.c b/source/blender/editors/util/editmode_undo.c
index cff30f12369..85f343e3311 100644
--- a/source/blender/editors/util/editmode_undo.c
+++ b/source/blender/editors/util/editmode_undo.c
@@ -314,6 +314,20 @@ void undo_editmode_name(bContext *C, const char *undoname)
 	}
 }
 
+/* undoname optionally, if NULL it just checks for existing undo steps */
+int undo_editmode_valid(const char *undoname)
+{
+	if(undoname) {
+		UndoElem *uel;
+		
+		for(uel= undobase.last; uel; uel= uel->prev) {
+			if(strcmp(undoname, uel->name)==0)
+				break;
+		}
+		return uel != NULL;
+	}
+	return undobase.last != undobase.first;
+}
 
 /* ************** for interaction with menu/pullown */
 
diff --git a/source/blender/editors/util/undo.c b/source/blender/editors/util/undo.c
index 60f526b940a..0158719b2fb 100644
--- a/source/blender/editors/util/undo.c
+++ b/source/blender/editors/util/undo.c
@@ -199,6 +199,52 @@ void ED_undo_pop_op(bContext *C, wmOperator *op)
 	ed_undo_step(C, 0, op->type->name);
 }
 
+/* name optionally, function used to check for operator redo panel */
+int ED_undo_valid(const bContext *C, const char *undoname)
+{
+	Object *obedit= CTX_data_edit_object(C);
+	Object *obact= CTX_data_active_object(C);
+	ScrArea *sa= CTX_wm_area(C);
+	
+	if(sa && sa->spacetype==SPACE_IMAGE) {
+		SpaceImage *sima= (SpaceImage *)sa->spacedata.first;
+		
+		if((obact && obact->mode & OB_MODE_TEXTURE_PAINT) || sima->flag & SI_DRAWTOOL) {
+			return 1;
+		}
+	}
+	
+	if(sa && sa->spacetype==SPACE_TEXT) {
+		return 1;
+	}
+	else if(obedit) {
+		if ELEM7(obedit->type, OB_MESH, OB_FONT, OB_CURVE, OB_SURF, OB_MBALL, OB_LATTICE, OB_ARMATURE) {
+			return undo_editmode_valid(undoname);
+		}
+	}
+	else {
+		
+		/* if below tests fail, global undo gets executed */
+		
+		if(obact && obact->mode & OB_MODE_TEXTURE_PAINT) {
+			if( ED_undo_paint_valid(UNDO_PAINT_IMAGE, undoname) )
+				return 1;
+		}
+		else if(obact && obact->mode & OB_MODE_SCULPT) {
+			if( ED_undo_paint_valid(UNDO_PAINT_MESH, undoname) )
+				return 1;
+		}
+		else if(obact && obact->mode & OB_MODE_PARTICLE_EDIT) {
+			return PE_undo_valid(CTX_data_scene(C));
+		}
+		
+		if(U.uiflag & USER_GLOBALUNDO) {
+			return BKE_undo_valid(undoname);
+		}
+	}
+	return 0;
+}
+
 static int ed_undo_exec(bContext *C, wmOperator *UNUSED(op))
 {
 	/* "last operator" should disappear, later we can tie ths with undo stack nicer */
diff --git a/source/blender/editors/util/util_intern.h b/source/blender/editors/util/util_intern.h
index 73675ab4ef9..b5750c55c87 100644
--- a/source/blender/editors/util/util_intern.h
+++ b/source/blender/editors/util/util_intern.h
@@ -34,6 +34,7 @@
 /* editmode_undo.c */
 void undo_editmode_clear(void);
 void undo_editmode_name(bContext *C, const char *undoname);
+int undo_editmode_valid(const char *undoname);
 
 #endif /* ED_UTIL_INTERN_H */