Collections: Operator to select collection objects

This is only supported by layer collections (the ones accessible
in the outliner when you see "View Layer").

source/blender/blenkernel/BKE_layer.h

@@ -108,6 +108,8 @@ void BKE_collection_enable(struct ViewLayer *view_layer, struct LayerCollection
 bool BKE_view_layer_has_collection(struct ViewLayer *view_layer, const struct SceneCollection *sc);
 bool BKE_scene_has_object(struct Scene *scene, struct Object *ob);
 
+void BKE_layer_collection_objects_select(struct LayerCollection *layer_collection);
+
 /* syncing */
 
 void BKE_layer_sync_new_scene_collection(struct ID *owner_id, const struct SceneCollection *sc_parent, struct SceneCollection *sc);

source/blender/blenkernel/intern/layer.c

@@ -987,6 +987,34 @@ void BKE_layer_collection_resync(const ID *owner_id, const SceneCollection *sc)
 
 /* ---------------------------------------------------------------------- */
 
+/**
+ * Select all the objects of this layer collection
+ *
+ * It also select the objects that are in nested collections.
+ * \note Recursive
+ */
+void BKE_layer_collection_objects_select(struct LayerCollection *layer_collection)
+{
+	if ((layer_collection->flag & COLLECTION_DISABLED) ||
+	    ((layer_collection->flag & COLLECTION_SELECTABLE) == 0))
+	{
+		return;
+	}
+
+	for (LinkData *link = layer_collection->object_bases.first; link; link = link->next) {
+		Base *base = link->data;
+		if (base->flag & BASE_SELECTABLED) {
+			base->flag |= BASE_SELECTED;
+		}
+	}
+
+	for (LayerCollection *iter = layer_collection->layer_collections.first; iter; iter = iter->next) {
+		BKE_layer_collection_objects_select(iter);
+	}
+}
+
+/* ---------------------------------------------------------------------- */
+
 /**
  * Link a collection to a renderlayer
  * The collection needs to be created separately

source/blender/editors/space_outliner/outliner_collections.c

@@ -757,3 +757,65 @@ void OUTLINER_OT_collection_toggle(wmOperatorType *ot)
 #undef ACTION_TOGGLE
 #undef ACTION_ENABLE
 #undef ACTION_DISABLE
+
+struct CollectionObjectsSelectData {
+	bool error;
+	LayerCollection *layer_collection;
+};
+
+static TreeTraversalAction outliner_find_first_selected_layer_collection(TreeElement *te, void *customdata)
+{
+	struct CollectionObjectsSelectData *data = customdata;
+	TreeStoreElem *tselem = TREESTORE(te);
+
+	switch (tselem->type) {
+		case TSE_LAYER_COLLECTION:
+			data->layer_collection = te->directdata;
+			return TRAVERSE_BREAK;
+		case TSE_LAYER_COLLECTION_BASE:
+			return TRAVERSE_CONTINUE;
+		default:
+			return TRAVERSE_SKIP_CHILDS;
+	}
+}
+
+static LayerCollection *outliner_active_layer_collection(bContext *C)
+{
+	SpaceOops *soops = CTX_wm_space_outliner(C);
+
+	struct CollectionObjectsSelectData data = {
+		.layer_collection = NULL,
+	};
+
+	outliner_tree_traverse(soops, &soops->tree, 0, TSE_SELECTED, outliner_find_first_selected_layer_collection, &data);
+	return data.layer_collection;
+}
+
+static int collection_objects_select_exec(bContext *C, wmOperator *UNUSED(op))
+{
+	LayerCollection *layer_collection = outliner_active_layer_collection(C);
+
+	if (layer_collection == NULL) {
+		return OPERATOR_CANCELLED;
+	}
+
+	BKE_layer_collection_objects_select(layer_collection);
+	WM_main_add_notifier(NC_SCENE | ND_OB_SELECT, CTX_data_scene(C));
+
+	return OPERATOR_FINISHED;
+}
+
+void OUTLINER_OT_collection_objects_select(wmOperatorType *ot)
+{
+	/* identifiers */
+	ot->name = "Select Objects";
+	ot->idname = "OUTLINER_OT_collection_objects_select";
+	ot->description = "Select all the collection objects";
+
+	/* api callbacks */
+	ot->exec = collection_objects_select_exec;
+	ot->poll = view_layer_editor_poll;
+
+	/* flags */
+	ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
+}

source/blender/editors/space_outliner/outliner_intern.h

@@ -345,6 +345,7 @@ void OUTLINER_OT_collection_link(struct wmOperatorType *ot);
 void OUTLINER_OT_collection_unlink(struct wmOperatorType *ot);
 void OUTLINER_OT_collection_new(struct wmOperatorType *ot);
 void OUTLINER_OT_collection_objects_remove(struct wmOperatorType *ot);
+void OUTLINER_OT_collection_objects_select(struct wmOperatorType *ot);
 
 void OUTLINER_OT_collection_objects_add(struct wmOperatorType *ot);
 void OUTLINER_OT_collection_nested_new(struct wmOperatorType *ot);

source/blender/editors/space_outliner/outliner_ops.c

@@ -479,6 +479,7 @@ void outliner_operatortypes(void)
 	WM_operatortype_append(OUTLINER_OT_collection_delete_selected);
 	WM_operatortype_append(OUTLINER_OT_collection_objects_add);
 	WM_operatortype_append(OUTLINER_OT_collection_objects_remove);
+	WM_operatortype_append(OUTLINER_OT_collection_objects_select);
 }
 
 static wmKeyMap *outliner_item_drag_drop_modal_keymap(wmKeyConfig *keyconf)

source/blender/editors/space_outliner/outliner_tools.c

@@ -675,6 +675,7 @@ typedef enum eOutliner_PropModifierOps {
 typedef enum eOutliner_PropCollectionOps {
 	OL_COLLECTION_OP_OBJECTS_ADD = 1,
 	OL_COLLECTION_OP_OBJECTS_REMOVE,
+	OL_COLLECTION_OP_OBJECTS_SELECT,
 	OL_COLLECTION_OP_COLLECTION_NEW,
 	OL_COLLECTION_OP_COLLECTION_DEL,
 	OL_COLLECTION_OP_COLLECTION_UNLINK,
@@ -860,6 +861,10 @@ static void collection_cb(int event, TreeElement *te, TreeStoreElem *UNUSED(tsel
 		WM_event_add_notifier(C, NC_SCENE | ND_LAYER, scene);
 		te->store_elem->flag &= ~TSE_SELECTED;
 	}
+	else if (event == OL_COLLECTION_OP_OBJECTS_SELECT) {
+		BKE_layer_collection_objects_select(lc);
+		WM_main_add_notifier(NC_SCENE | ND_OB_SELECT, scene);
+	}
 	else if (event == OL_COLLECTION_OP_COLLECTION_NEW) {
 		if (GS(id->name) == ID_GR) {
 			BKE_collection_add(id, sc, COLLECTION_TYPE_GROUP_INTERNAL, NULL);
@@ -1844,6 +1849,7 @@ void OUTLINER_OT_modifier_operation(wmOperatorType *ot)
 static EnumPropertyItem prop_collection_op_types[] = {
 	{OL_COLLECTION_OP_OBJECTS_ADD, "OBJECTS_ADD", ICON_ZOOMIN, "Add Selected", "Add selected objects to collection"},
 	{OL_COLLECTION_OP_OBJECTS_REMOVE, "OBJECTS_REMOVE", ICON_X, "Remove Selected", "Remove selected objects from collection"},
+	{OL_COLLECTION_OP_OBJECTS_SELECT, "OBJECTS_SELECT", ICON_RESTRICT_SELECT_OFF, "Select Objects", "Selected collection objects"},
 	{OL_COLLECTION_OP_COLLECTION_NEW, "COLLECTION_NEW", ICON_NEW, "New Collection", "Add a new nested collection"},
 	{OL_COLLECTION_OP_COLLECTION_UNLINK, "COLLECTION_UNLINK", ICON_UNLINKED, "Unlink", "Unlink collection"},
 	{OL_COLLECTION_OP_COLLECTION_DEL, "COLLECTION_DEL", ICON_X, "Delete Collection", "Delete the collection"},
@@ -1880,7 +1886,10 @@ static int outliner_collection_operation_invoke(bContext *C, wmOperator *op, con
 
 	for (int i = 0; i < (ARRAY_SIZE(prop_collection_op_types) - 1); i++, prop++) {
 		if (soops->outlinevis != SO_GROUPS ||
-		    !ELEM(prop->value, OL_COLLECTION_OP_COLLECTION_UNLINK, OL_COLLECTION_OP_GROUP_CREATE))
+		    !ELEM(prop->value,
+		          OL_COLLECTION_OP_OBJECTS_SELECT,
+		          OL_COLLECTION_OP_COLLECTION_UNLINK,
+		          OL_COLLECTION_OP_GROUP_CREATE))
 		{
 			uiItemEnumO_ptr(layout, ot, NULL, prop->icon, "type", prop->value);
 		}