UI: Support C defined menu types to listen to notifiers

Needed to dynamically load assets as menu items, see cf985180551d and
99e5024e97f1. The next commit will add the listener for the node add menu.

4 files changed, 34 insertions, 1 deletions

diff --git a/source/blender/editors/interface/interface.cc b/source/blender/editors/interface/interface.cc
index 1f88d25af2b..331d1581db5 100644
--- a/source/blender/editors/interface/interface.cc
+++ b/source/blender/editors/interface/interface.cc
@@ -3474,6 +3474,7 @@ void UI_block_free(const bContext *C, uiBlock *block)
 
   BLI_freelistN(&block->saferct);
   BLI_freelistN(&block->color_pickers.list);
+  BLI_freelistN(&block->dynamic_listeners);
 
   ui_block_free_button_groups(block);
   ui_block_free_views(block);
@@ -3481,6 +3482,20 @@ void UI_block_free(const bContext *C, uiBlock *block)
   MEM_freeN(block);
 }
 
+void UI_block_listen(const uiBlock *block, const wmRegionListenerParams *listener_params)
+{
+  /* Don't need to let invisible blocks (old blocks from previous redraw) listen. */
+  if (!block->active) {
+    return;
+  }
+
+  LISTBASE_FOREACH (uiBlockDynamicListener *, listener, &block->dynamic_listeners) {
+    listener->listener_func(listener_params);
+  }
+
+  ui_block_views_listen(block, listener_params);
+}
+
 void UI_blocklist_update_window_matrix(const bContext *C, const ListBase *lb)
 {
   ARegion *region = CTX_wm_region(C);
diff --git a/source/blender/editors/interface/interface_intern.h b/source/blender/editors/interface/interface_intern.h
index 6ef81ad897e..982ac1753e1 100644
--- a/source/blender/editors/interface/interface_intern.h
+++ b/source/blender/editors/interface/interface_intern.h
@@ -477,6 +477,12 @@ typedef enum uiButtonGroupFlag {
 } uiButtonGroupFlag;
 ENUM_OPERATORS(uiButtonGroupFlag, UI_BUTTON_GROUP_PANEL_HEADER);
 
+typedef struct uiBlockDynamicListener {
+  struct uiBlockDynamicListener *next, *prev;
+
+  void (*listener_func)(const struct wmRegionListenerParams *params);
+} uiBlockDynamicListener;
+
 struct uiBlock {
   uiBlock *next, *prev;
 
@@ -499,6 +505,8 @@ struct uiBlock {
    * state that is persistent over redraws (e.g. collapsed tree-view items). */
   ListBase views;
 
+  ListBase dynamic_listeners; /* #uiBlockDynamicListener */
+
   char name[UI_MAX_NAME_STR];
 
   float winmat[4][4];
@@ -1540,6 +1548,8 @@ void ui_interface_tag_script_reload_queries(void);
 /* interface_view.cc */
 
 void ui_block_free_views(struct uiBlock *block);
+void ui_block_views_listen(const uiBlock *block,
+                           const struct wmRegionListenerParams *listener_params);
 uiViewHandle *ui_block_view_find_matching_in_old_block(const uiBlock *new_block,
                                                        const uiViewHandle *new_view);
 
diff --git a/source/blender/editors/interface/interface_layout.c b/source/blender/editors/interface/interface_layout.c
index 496f72c089a..a456cef7be6 100644
--- a/source/blender/editors/interface/interface_layout.c
+++ b/source/blender/editors/interface/interface_layout.c
@@ -5814,6 +5814,14 @@ void UI_menutype_draw(bContext *C, MenuType *mt, struct uiLayout *layout)
     printf("%s: opening menu \"%s\"\n", __func__, mt->idname);
   }
 
+  if (mt->listener) {
+    /* Forward the menu type listener to the block we're drawing in. */
+    uiBlock *block = uiLayoutGetBlock(layout);
+    uiBlockDynamicListener *listener = MEM_mallocN(sizeof(*listener), "uiBlockDynamicListener");
+    listener->listener_func = mt->listener;
+    BLI_addtail(&block->dynamic_listeners, listener);
+  }
+
   if (layout->context) {
     CTX_store_set(C, layout->context);
   }
diff --git a/source/blender/editors/interface/views/interface_view.cc b/source/blender/editors/interface/views/interface_view.cc
index c568a8cab74..71974b4d2f9 100644
--- a/source/blender/editors/interface/views/interface_view.cc
+++ b/source/blender/editors/interface/views/interface_view.cc
@@ -81,7 +81,7 @@ void ui_block_free_views(uiBlock *block)
   }
 }
 
-void UI_block_views_listen(const uiBlock *block, const wmRegionListenerParams *listener_params)
+void ui_block_views_listen(const uiBlock *block, const wmRegionListenerParams *listener_params)
 {
   ARegion *region = listener_params->region;