From 4e3fe6b4c0027dada181892c019e49f8003612fe Mon Sep 17 00:00:00 2001
From: Po Lu <luangruo@yahoo.com>
Date: Wed, 20 Oct 2021 10:54:27 +0800
Subject: [PATCH] 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.
---
 lisp/menu-bar.el |  8 +++++---
 src/nsmenu.m     | 41 ++++++++++++++++++++++++++++++++++++++++-
 src/nsterm.m     |  1 +
 3 files changed, 46 insertions(+), 4 deletions(-)

diff --git a/lisp/menu-bar.el b/lisp/menu-bar.el
index 980ba2fcd1..2ef24cf111 100644
--- a/lisp/menu-bar.el
+++ b/lisp/menu-bar.el
@@ -2659,9 +2659,10 @@ menu-bar-open
 this is the numeric argument to the command.
 This function decides which method to use to access the menu
 depending on FRAME's terminal device.  On X displays, it calls
-`x-menu-bar-open'; on Windows, `w32-menu-bar-open'; otherwise it
-calls either `popup-menu' or `tmm-menubar' depending on whether
-`tty-menu-open-use-tmm' is nil or not.
+`x-menu-bar-open'; on Windows, `w32-menu-bar-open';
+on NS, `ns-menu-bar-open'; otherwise it calls either `popup-menu'
+or `tmm-menubar' depending on whether `tty-menu-open-use-tmm'
+is nil or not.
 
 If FRAME is nil or not given, use the selected frame."
   (interactive
@@ -2670,6 +2671,7 @@ menu-bar-open
     (cond
      ((eq type 'x) (x-menu-bar-open frame))
      ((eq type 'w32) (w32-menu-bar-open frame))
+     ((eq type 'ns) (ns-menu-bar-open frame))
      ((and (null tty-menu-open-use-tmm)
 	   (not (zerop (or (frame-parameter nil 'menu-bar-lines) 0))))
       ;; Make sure the menu bar is up to date.  One situation where
diff --git a/src/nsmenu.m b/src/nsmenu.m
index 333a8b50a1..359a9c3bc8 100644
--- a/src/nsmenu.m
+++ b/src/nsmenu.m
@@ -1451,7 +1451,30 @@ - (NSRect) frame
 
 @end  /* EmacsTooltip */
 
+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
+	  [menu performActionForItemAtIndex: [menu indexOfItem: item]];
+#endif
+	  break;
+	}
+    }
+  unblock_input ();
+}
 
 /* ==========================================================================
 
@@ -1883,7 +1906,6 @@ - (Lisp_Object)runDialogAt: (NSPoint)p
 
 @end
 
-
 /* ==========================================================================
 
     Lisp definitions
@@ -1906,6 +1928,22 @@ - (Lisp_Object)runDialogAt: (NSPoint)p
   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
@@ -1917,6 +1955,7 @@ - (Lisp_Object)runDialogAt: (NSPoint)p
 {
   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 e0b7143e29..cd322b1fce 100644
--- a/src/nsterm.m
+++ b/src/nsterm.m
@@ -5071,6 +5071,7 @@ static Lisp_Object ns_new_font (struct frame *f, Lisp_Object font_object,
   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;
-- 
2.31.1