UI: add menu search functionality to operator search menu

This has some advantages over operator search:

- Some operators need options set to be usefully accessed.
- Shows key bindings to access menus
  (for actions that don't have key bindings themselves).
- Non operator actions such as check-boxes are also shown.
- Menu items can control execution context, using invoke or execute
  where appropriate so we can control how the operator runs.

Part of the design task T74157.

This can be tested using the 'Experimental' preferences section
or selected in the key-map editor.

source/blender/editors/interface/interface_region_search.c

@@ -73,6 +73,7 @@ struct uiSearchItems {
   char **names;
   void **pointers;
   int *icons;
+  int *states;
 
   AutoComplete *autocpl;
   void *active;
@@ -95,9 +96,18 @@ typedef struct uiSearchboxData {
 
 #define SEARCH_ITEMS 10
 
-/* exported for use by search callbacks */
-/* returns zero if nothing to add */
-bool UI_search_item_add(uiSearchItems *items, const char *name, void *poin, int iconid)
+/**
+ * Public function exported for functions that use #UI_BTYPE_SEARCH_MENU.
+ *
+ * \param items: Stores the items.
+ * \param name: Text to display for the item.
+ * \param poin: Opaque pointer (for use by the caller).
+ * \param iconid: The icon, #ICON_NONE for no icon.
+ * \param state: The buttons state flag, compatible with #uiBut.flag,
+ * typically #UI_BUT_DISABLED / #UI_BUT_INACTIVE.
+ * \return false if there is nothing to add.
+ */
+bool UI_search_item_add(uiSearchItems *items, const char *name, void *poin, int iconid, int state)
 {
   /* hijack for autocomplete */
   if (items->autocpl) {
@@ -135,6 +145,13 @@ bool UI_search_item_add(uiSearchItems *items, const char *name, void *poin, int
     items->icons[items->totitem] = iconid;
   }
 
+  /* Limit flags that can be set so flags such as 'UI_SELECT' aren't accidentally set
+   * which will cause problems, add others as needed. */
+  BLI_assert((state & ~(UI_BUT_DISABLED | UI_BUT_INACTIVE | UI_BUT_REDALERT)) == 0);
+  if (items->states) {
+    items->states[items->totitem] = state;
+  }
+
   items->totitem++;
 
   return true;
@@ -421,17 +438,16 @@ static void ui_searchbox_region_draw_cb(const bContext *C, ARegion *region)
     if (data->preview) {
       /* draw items */
       for (a = 0; a < data->items.totitem; a++) {
+        const int state = ((a == data->active) ? UI_ACTIVE : 0) | data->items.states[a];
+
         /* ensure icon is up-to-date */
         ui_icon_ensure_deferred(C, data->items.icons[a], data->preview);
 
         ui_searchbox_butrect(&rect, data, a);
 
         /* widget itself */
-        ui_draw_preview_item(&data->fstyle,
-                             &rect,
-                             data->items.names[a],
-                             data->items.icons[a],
-                             (a == data->active) ? UI_ACTIVE : 0);
+        ui_draw_preview_item(
+            &data->fstyle, &rect, data->items.names[a], data->items.icons[a], state);
       }
 
       /* indicate more */
@@ -451,6 +467,8 @@ static void ui_searchbox_region_draw_cb(const bContext *C, ARegion *region)
     else {
       /* draw items */
       for (a = 0; a < data->items.totitem; a++) {
+        const int state = ((a == data->active) ? UI_ACTIVE : 0) | data->items.states[a];
+
         ui_searchbox_butrect(&rect, data, a);
 
         /* widget itself */
@@ -458,7 +476,7 @@ static void ui_searchbox_region_draw_cb(const bContext *C, ARegion *region)
                           &rect,
                           data->items.names[a],
                           data->items.icons[a],
-                          (a == data->active) ? UI_ACTIVE : 0,
+                          state,
                           data->use_sep);
       }
       /* indicate more */
@@ -490,6 +508,7 @@ static void ui_searchbox_region_free_cb(ARegion *region)
   MEM_freeN(data->items.names);
   MEM_freeN(data->items.pointers);
   MEM_freeN(data->items.icons);
+  MEM_freeN(data->items.states);
 
   MEM_freeN(data);
   region->regiondata = NULL;
@@ -657,6 +676,7 @@ ARegion *ui_searchbox_create_generic(bContext *C, ARegion *butregion, uiBut *but
   data->items.names = MEM_callocN(data->items.maxitem * sizeof(void *), "search names");
   data->items.pointers = MEM_callocN(data->items.maxitem * sizeof(void *), "search pointers");
   data->items.icons = MEM_callocN(data->items.maxitem * sizeof(int), "search icons");
+  data->items.states = MEM_callocN(data->items.maxitem * sizeof(int), "search flags");
   for (i = 0; i < data->items.maxitem; i++) {
     data->items.names[i] = MEM_callocN(but->hardmax + 1, "search pointers");
   }
@@ -718,9 +738,9 @@ static void ui_searchbox_region_draw_cb__operator(const bContext *UNUSED(C), ARe
       /* widget itself */
       /* NOTE: i18n messages extracting tool does the same, please keep it in sync. */
       {
-        wmOperatorType *ot = data->items.pointers[a];
+        const int state = ((a == data->active) ? UI_ACTIVE : 0) | data->items.states[a];
 
-        int state = (a == data->active) ? UI_ACTIVE : 0;
+        wmOperatorType *ot = data->items.pointers[a];
         char text_pre[128];
         char *text_pre_p = strstr(ot->idname, "_OT_");
         if (text_pre_p == NULL) {
@@ -780,6 +800,25 @@ void ui_searchbox_free(bContext *C, ARegion *region)
   ui_region_temp_remove(C, CTX_wm_screen(C), region);
 }
 
+static void ui_searchbox_region_draw_cb__menu(const bContext *UNUSED(C), ARegion *UNUSED(region))
+{
+  /* Currently unused. */
+}
+
+ARegion *ui_searchbox_create_menu(bContext *C, ARegion *butregion, uiBut *but)
+{
+  ARegion *region;
+
+  UI_but_drawflag_enable(but, UI_BUT_HAS_SHORTCUT);
+  region = ui_searchbox_create_generic(C, butregion, but);
+
+  if (false) {
+    region->type->draw = ui_searchbox_region_draw_cb__menu;
+  }
+
+  return region;
+}
+
 /* sets red alert if button holds a string it can't find */
 /* XXX weak: search_func adds all partial matches... */
 void ui_but_search_refresh(uiBut *but)