UI: List library overrides in the Outliner

Having a centeral place to find a list of all library overrides should be
useful for managing production scenes where library overrides are used a lot.
This change adds the individually overridden properties of a data-block under
the data-block itself. Just how we show modifiers, constraints or pose channels
there. This way we can also expose library override operations/options better
in future.

There's also a filter option for the library overrides now, so they can be
hidden. It is only available in the View Layer display mode though, like the
other filter options.

One internal change this has to do is adding more informative return values to
undo pushes and the library override functions called by it. That way we can
send a notifier when library overrides change for the Outliner to know when to
rebuild the tree.

Differential Revision: https://developer.blender.org/D7631

Reviewed by: Andy Goralczyk, Bastien Montagne, William Reynish

1 files changed, 14 insertions, 10 deletions

diff --git a/source/blender/blenkernel/intern/undo_system.c b/source/blender/blenkernel/intern/undo_system.c
index b687254fd69..078c93532d9 100644
--- a/source/blender/blenkernel/intern/undo_system.c
+++ b/source/blender/blenkernel/intern/undo_system.c
@@ -342,9 +342,10 @@ static bool undosys_stack_push_main(UndoStack *ustack, const char *name, struct
   CLOG_INFO(&LOG, 1, "'%s'", name);
   bContext *C_temp = CTX_create();
   CTX_data_main_set(C_temp, bmain);
-  bool ok = BKE_undosys_step_push_with_type(ustack, C_temp, name, BKE_UNDOSYS_TYPE_MEMFILE);
+  UndoPushReturn ret = BKE_undosys_step_push_with_type(
+      ustack, C_temp, name, BKE_UNDOSYS_TYPE_MEMFILE);
   CTX_free(C_temp);
-  return ok;
+  return (ret & UNDO_PUSH_RET_SUCCESS);
 }
 
 void BKE_undosys_stack_init_from_main(UndoStack *ustack, struct Main *bmain)
@@ -495,18 +496,21 @@ UndoStep *BKE_undosys_step_push_init(UndoStack *ustack, bContext *C, const char
 /**
  * \param C: Can be NULL from some callers if their encoding function doesn't need it
  */
-bool BKE_undosys_step_push_with_type(UndoStack *ustack,
-                                     bContext *C,
-                                     const char *name,
-                                     const UndoType *ut)
+UndoPushReturn BKE_undosys_step_push_with_type(UndoStack *ustack,
+                                               bContext *C,
+                                               const char *name,
+                                               const UndoType *ut)
 {
   UNDO_NESTED_ASSERT(false);
   undosys_stack_validate(ustack, false);
   bool is_not_empty = ustack->step_active != NULL;
+  UndoPushReturn retval = UNDO_PUSH_RET_FAILURE;
 
   /* Might not be final place for this to be called - probably only want to call it from some
    * undo handlers, not all of them? */
-  BKE_lib_override_library_main_operations_create(G_MAIN, false);
+  if (BKE_lib_override_library_main_operations_create(G_MAIN, false)) {
+    retval |= UNDO_PUSH_RET_OVERRIDE_CHANGED;
+  }
 
   /* Remove all undos after (also when 'ustack->step_active == NULL'). */
   while (ustack->steps.last != ustack->step_active) {
@@ -558,7 +562,7 @@ bool BKE_undosys_step_push_with_type(UndoStack *ustack,
     if (!undosys_step_encode(C, G_MAIN, ustack, us)) {
       MEM_freeN(us);
       undosys_stack_validate(ustack, true);
-      return false;
+      return retval;
     }
     ustack->step_active = us;
     BLI_addtail(&ustack->steps, us);
@@ -589,10 +593,10 @@ bool BKE_undosys_step_push_with_type(UndoStack *ustack,
   }
 
   undosys_stack_validate(ustack, true);
-  return true;
+  return (retval | UNDO_PUSH_RET_SUCCESS);
 }
 
-bool BKE_undosys_step_push(UndoStack *ustack, bContext *C, const char *name)
+UndoPushReturn BKE_undosys_step_push(UndoStack *ustack, bContext *C, const char *name)
 {
   UNDO_NESTED_ASSERT(false);
   const UndoType *ut = ustack->step_init ? ustack->step_init->type :