libobs: Add callback for enumerating all scene children

Prevents infinite recursion when adding children to a scene.

libobs/obs-scene.c

@@ -162,7 +162,7 @@ static void scene_destroy(void *data)
 
 static void scene_enum_sources(void *data,
 		obs_source_enum_proc_t enum_callback,
-		void *param)
+		void *param, bool active)
 {
 	struct obs_scene *scene = data;
 	struct obs_scene_item *item;
@@ -175,7 +175,7 @@ static void scene_enum_sources(void *data,
 		next = item->next;
 
 		obs_sceneitem_addref(item);
-		if (os_atomic_load_long(&item->active_refs) > 0)
+		if (!active || os_atomic_load_long(&item->active_refs) > 0)
 			enum_callback(scene->source, item->source, param);
 		obs_sceneitem_release(item);
 
@@ -185,6 +185,20 @@ static void scene_enum_sources(void *data,
 	full_unlock(scene);
 }
 
+static void scene_enum_active_sources(void *data,
+		obs_source_enum_proc_t enum_callback,
+		void *param)
+{
+	scene_enum_sources(data, enum_callback, param, true);
+}
+
+static void scene_enum_all_sources(void *data,
+		obs_source_enum_proc_t enum_callback,
+		void *param)
+{
+	scene_enum_sources(data, enum_callback, param, false);
+}
+
 static inline void detach_sceneitem(struct obs_scene_item *item)
 {
 	if (item->prev)
@@ -957,7 +971,8 @@ const struct obs_source_info scene_info =
 	.get_height    = scene_getheight,
 	.load          = scene_load,
 	.save          = scene_save,
-	.enum_active_sources = scene_enum_sources
+	.enum_active_sources = scene_enum_active_sources,
+	.enum_all_sources = scene_enum_all_sources
 };
 
 obs_scene_t *obs_scene_create(const char *name)