Support opening the toolkit menu bar on NS

* src/nsmenu.m (ns_activate_menubar, Fns_open_menubar): New functions.
* src/nsterm.m (ns_create_terminal): Add activate_menubar_hook.
* lisp/menu-bar.el (menu-bar-open): Use ns-menu-bar-open on Nextstep.

2 files changed, 56 insertions, 0 deletions

diff --git a/src/nsmenu.m b/src/nsmenu.m
index 29201e69079..b93d3a79bdc 100644
--- a/src/nsmenu.m
+++ b/src/nsmenu.m
@@ -439,6 +439,44 @@ set_frame_menubar (struct frame *f, bool deep_p)
   ns_update_menubar (f, deep_p);
 }
 
+void
+ns_activate_menubar (struct frame *frame)
+{
+  if (frame != SELECTED_FRAME ()
+      || !FRAME_EXTERNAL_MENU_BAR (frame))
+    return;
+
+  block_input ();
+  NSApplication *app = [NSApplication sharedApplication];
+  NSMenu *menu = [app mainMenu];
+  for (NSMenuItem *item in [menu itemArray])
+    {
+      if ([item hasSubmenu])
+        {
+#ifdef NS_IMPL_GNUSTEP
+          [[item submenu] display];
+#else
+          NSWindow *window = [FRAME_NS_VIEW (frame) window];
+          NSScreen *screen = [window screen];
+
+          NSRect screen_frame = [screen frame];
+          [app postEvent: [NSEvent mouseEventWithType: NSLeftMouseDown
+                                             location: NSMakePoint (NSMinX (screen_frame),
+                                                                    NSMinY (screen_frame) + 10)
+                                        modifierFlags: 0
+                                            timestamp: 0
+                                         windowNumber: [window windowNumber]
+                                              context: [NSGraphicsContext currentContext]
+                                          eventNumber: 0
+                                           clickCount: 1
+                                             pressure: 1.0f]
+                 atStart: YES];
+#endif
+          break;
+        }
+    }
+  unblock_input ();
+}
 
 /* ==========================================================================
 
@@ -1916,6 +1954,22 @@ DEFUN ("menu-or-popup-active-p", Fmenu_or_popup_active_p, Smenu_or_popup_active_
   return popup_activated () ? Qt : Qnil;
 }
 
+DEFUN ("ns-menu-bar-open", Fns_menu_bar_open, Sns_menu_bar_open, 0, 1, "i",
+       doc: /* Start key navigation of the menu bar in FRAME.
+This initially opens the first menu bar item and you can then navigate with the
+arrow keys, select a menu entry with the return key or cancel with the
+escape key.  If FRAME has no menu bar this function does nothing.
+
+If FRAME is nil or not given, use the selected frame.  */)
+  (Lisp_Object frame)
+{
+  struct frame *f = decode_window_system_frame (frame);
+
+  ns_activate_menubar (f);
+
+  return Qnil;
+}
+
 /* ==========================================================================
 
     Lisp interface declaration
@@ -1927,6 +1981,7 @@ syms_of_nsmenu (void)
 {
   defsubr (&Sns_reset_menu);
   defsubr (&Smenu_or_popup_active_p);
+  defsubr (&Sns_menu_bar_open);
 
   DEFSYM (Qdebug_on_next_call, "debug-on-next-call");
 }
diff --git a/src/nsterm.m b/src/nsterm.m
index ed0e7a2aae8..4e84e130b89 100644
--- a/src/nsterm.m
+++ b/src/nsterm.m
@@ -5067,6 +5067,7 @@ ns_create_terminal (struct ns_display_info *dpyinfo)
   terminal->delete_frame_hook = ns_destroy_window;
   terminal->delete_terminal_hook = ns_delete_terminal;
   terminal->change_tab_bar_height_hook = ns_change_tab_bar_height;
+  terminal->activate_menubar_hook = ns_activate_menubar;
   /* Other hooks are NULL by default.  */
 
   return terminal;