/* Implements an elisp-programmable menubar -- X interface.
   Copyright (C) 1993, 1994 Free Software Foundation, Inc.
   Copyright (C) 1995 Tinker Systems and INS Engineering Corp.
   Copyright (C) 2000 Ben Wing.

This file is part of XEmacs.

XEmacs is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 2, or (at your option) any
later version.

XEmacs is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
for more details.

You should have received a copy of the GNU General Public License
along with XEmacs; see the file COPYING.  If not, write to
the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.  */

/* Synched up with: Not in FSF. */

/* This file Mule-ized by Ben Wing, 7-8-00. */

/* Authorship:

   Created 16-dec-91 by Jamie Zawinski.
   Menu filters and many other keywords added by Stig for 19.12.
   Original device-abstraction work and GC cleanup work by Ben Wing for 19.13.
   Menu accelerators c. 1997? by ??.  Moved here from event-stream.c.
   Other work post-1996 by ??.
*/

#include <config.h>
#include "lisp.h"

#include "console-x.h"
#include "EmacsFrame.h"
#include "gui-x.h"
#include "../lwlib/lwlib.h"

#include "buffer.h"
#include "commands.h"           /* zmacs_regions */
#include "events.h"
#include "frame.h"
#include "gui.h"
#include "keymap.h"
#include "menubar.h"
#include "opaque.h"
#include "window.h"

static int set_frame_menubar (struct frame *f,
			      int deep_p,
			      int first_time_p);

#define FRAME_MENUBAR_DATA(frame) ((frame)->menubar_data)
#define XFRAME_MENUBAR_DATA(frame) XPOPUP_DATA ((frame)->menubar_data)

#define MENUBAR_TYPE	0
#define SUBMENU_TYPE	1
#define POPUP_TYPE	2


/* Converting Lisp menu tree descriptions to lwlib's `widget_value' form.

   menu_item_descriptor_to_widget_value() converts a lisp description of a
   menubar into a tree of widget_value structures.  It allocates widget_values
   with malloc_widget_value() and allocates other storage only for the `key'
   slot.  All other slots are filled with pointers to Lisp_String data.  We
   allocate a widget_value description of the menu or menubar, and hand it to
   lwlib, which then makes a copy of it, which it manages internally.  We then
   immediately free our widget_value tree; it will not be referenced again.

   Incremental menu construction callbacks operate just a bit differently.
   They allocate widget_values and call replace_widget_value_tree() to tell
   lwlib to destructively modify the incremental stub (subtree) of its
   separate widget_value tree.

   This function is highly recursive (it follows the menu trees) and may call
   eval.  The reason we keep pointers to lisp string data instead of copying
   it and freeing it later is to avoid the speed penalty that would entail
   (since this needs to be fast, in the simple cases at least).  (The reason
   we malloc/free the keys slot is because there's not a lisp string around
   for us to use in that case.)

   Since we keep pointers to lisp strings, and we call eval, we could lose if
   GC relocates (or frees) those strings.  It's not easy to gc protect the
   strings because of the recursive nature of this function, and the fact that
   it returns a data structure that gets freed later.  So...  we do the
   sleaziest thing possible and inhibit GC for the duration.  This is probably
   not a big deal...

   We do not have to worry about the pointers to Lisp_String data after
   this function successfully finishes.  lwlib copies all such data with
   strdup().  */

static widget_value *
menu_item_descriptor_to_widget_value_1 (Lisp_Object desc,
					int menu_type, int deep_p,
					int filter_p,
					int depth)
{
  /* This function cannot GC.
     It is only called from menu_item_descriptor_to_widget_value, which
     prohibits GC. */
  int menubar_root_p = (menu_type == MENUBAR_TYPE && depth == 0);
  int count = specpdl_depth ();
  int partition_seen = 0;
  widget_value *wv = xmalloc_widget_value ();
  Lisp_Object wv_closure = make_opaque_ptr (wv);

  record_unwind_protect (widget_value_unwind, wv_closure);

  if (STRINGP (desc))
    {
      Bufbyte *string_chars = XSTRING_DATA (desc);
      wv->type = (separator_string_p (string_chars) ? SEPARATOR_TYPE :
		  TEXT_TYPE);
      if (wv->type == SEPARATOR_TYPE)
	{
	  wv->value = menu_separator_style_and_to_external (string_chars);
	}
      else
	{
	  LISP_STRING_TO_EXTERNAL_MALLOC (desc, wv->name, Qlwlib_encoding);
	  wv->enabled = 1;
	  /* dverna Dec. 98: command_builder_operate_menu_accelerator will
	     manipulate the accel as a Lisp_Object if the widget has a name.
	     Since simple labels have a name, but no accel, we *must* set it
	     to nil */
	  wv->accel = LISP_TO_VOID (Qnil);
	}
    }
  else if (VECTORP (desc))
    {
      Lisp_Object gui_item = gui_parse_item_keywords (desc);
      if (!button_item_to_widget_value (Qmenubar,
					gui_item, wv, 1,
					(menu_type == MENUBAR_TYPE
					 && depth <= 1), 1, 1))
	{
	  /* :included form was nil */
	  wv = NULL;
	  goto menu_item_done;
	}
    }
  else if (CONSP (desc))
    {
      Lisp_Object incremental_data = desc;
      widget_value *prev = 0;

      if (STRINGP (XCAR (desc)))
	{
	  Lisp_Object key, val;
	  Lisp_Object include_p = Qnil, hook_fn = Qnil, config_tag = Qnil;
	  Lisp_Object active_p = Qt;
	  Lisp_Object accel;
	  int included_spec = 0;
	  int active_spec = 0;
	  wv->type = CASCADE_TYPE;
	  wv->enabled = 1;
	  wv->name = add_accel_and_to_external (XCAR (desc));

	  accel = gui_name_accelerator (XCAR (desc));
	  wv->accel = LISP_TO_VOID (accel);

	  desc = Fcdr (desc);

	  while (key = Fcar (desc), KEYWORDP (key))
	    {
	      Lisp_Object cascade = desc;
	      desc = Fcdr (desc);
	      if (NILP (desc))
		syntax_error ("Keyword in menu lacks a value", cascade);
	      val = Fcar (desc);
	      desc = Fcdr (desc);
	      if (EQ (key, Q_included))
		include_p = val, included_spec = 1;
	      else if (EQ (key, Q_config))
		config_tag = val;
	      else if (EQ (key, Q_filter))
		hook_fn = val;
	      else if (EQ (key, Q_active))
		active_p = val, active_spec = 1;
	      else if (EQ (key, Q_accelerator))
		{
		  if ( SYMBOLP (val)
		       || CHARP (val))
		    wv->accel = LISP_TO_VOID (val);
		  else
		    syntax_error ("bad keyboard accelerator", val);
		}
	      else if (EQ (key, Q_label))
		{
		  /* implement in 21.2 */
		}
	      else
		syntax_error ("Unknown menu cascade keyword", cascade);
	    }

	  if ((!NILP (config_tag)
	       && NILP (Fmemq (config_tag, Vmenubar_configuration)))
	      || (included_spec && NILP (Feval (include_p))))
	    {
	      wv = NULL;
	      goto menu_item_done;
	    }

	  if (active_spec)
	    active_p = Feval (active_p);

	  if (!NILP (hook_fn) && !NILP (active_p))
	    {
#if defined LWLIB_MENUBARS_LUCID || defined LWLIB_MENUBARS_MOTIF
	      if (filter_p || depth == 0)
		{
#endif
		  desc = call1_trapping_errors ("Error in menubar filter",
						hook_fn, desc);
		  if (UNBOUNDP (desc))
		    desc = Qnil;
#if defined LWLIB_MENUBARS_LUCID || defined LWLIB_MENUBARS_MOTIF
		}
	      else
		{
		  widget_value *incr_wv = xmalloc_widget_value ();
		  wv->contents = incr_wv;
		  incr_wv->type = INCREMENTAL_TYPE;
		  incr_wv->enabled = 1;
		  incr_wv->name = wv->name;
		  incr_wv->name = xstrdup (wv->name);
		  /* This is automatically GC protected through
		     the call to lw_map_widget_values(); no need
		     to worry. */
		  incr_wv->call_data = LISP_TO_VOID (incremental_data);
		  goto menu_item_done;
		}
#endif /* LWLIB_MENUBARS_LUCID || LWLIB_MENUBARS_MOTIF */
	    }
	  if (menu_type == POPUP_TYPE && popup_menu_titles && depth == 0)
	    {
	      /* Simply prepend three more widget values to the contents of
		 the menu: a label, and two separators (to get a double
		 line). */
	      widget_value *title_wv = xmalloc_widget_value ();
	      widget_value *sep_wv = xmalloc_widget_value ();
	      title_wv->type = TEXT_TYPE;
	      title_wv->name = xstrdup (wv->name);
	      title_wv->enabled = 1;
	      title_wv->next = sep_wv;
	      sep_wv->type = SEPARATOR_TYPE;
	      sep_wv->value = menu_separator_style_and_to_external ((Bufbyte *) "==");
	      sep_wv->next = 0;

	      wv->contents = title_wv;
	      prev = sep_wv;
	    }
	  wv->enabled = ! NILP (active_p);
	  if (deep_p && !wv->enabled  && !NILP (desc))
	    {
	      widget_value *dummy;
	      /* Add a fake entry so the menus show up */
	      wv->contents = dummy = xmalloc_widget_value ();
	      dummy->name = xstrdup ("(inactive)");
	      dummy->accel = LISP_TO_VOID (Qnil);
	      dummy->enabled = 0;
	      dummy->selected = 0;
	      dummy->value = NULL;
	      dummy->type = BUTTON_TYPE;
	      dummy->call_data = NULL;
	      dummy->next = NULL;

	      goto menu_item_done;
	    }

	}
      else if (menubar_root_p)
	{
	  wv->name = xstrdup ("menubar");
	  wv->type = CASCADE_TYPE; /* Well, nothing else seems to fit and
				      this is ignored anyway...  */
	}
      else
	{
	  syntax_error ("Menu name (first element) must be a string", desc);
	}

      if (deep_p || menubar_root_p)
	{
	  widget_value *next;
	  for (; !NILP (desc); desc = Fcdr (desc))
	    {
	      Lisp_Object child = Fcar (desc);
	      if (menubar_root_p && NILP (child))	/* the partition */
		{
		  if (partition_seen)
		    syntax_error
		      ("More than one partition (nil) in menubar description",
		       desc);
		  partition_seen = 1;
		  next = xmalloc_widget_value ();
		  next->type = PUSHRIGHT_TYPE;
		}
	      else
		{
		  next = menu_item_descriptor_to_widget_value_1
		    (child, menu_type, deep_p, filter_p, depth + 1);
		}
	      if (! next)
		continue;
	      else if (prev)
		prev->next = next;
	      else
		wv->contents = next;
	      prev = next;
	    }
	}
      if (deep_p && !wv->contents)
	wv = NULL;
    }
  else if (NILP (desc))
    syntax_error ("nil may not appear in menu descriptions", desc);
  else
    syntax_error ("Unrecognized menu descriptor", desc);

 menu_item_done:

  if (wv)
    {
      /* Completed normally.  Clear out the object that widget_value_unwind()
	 will be called with to tell it not to free the wv (as we are
	 returning it.) */
      set_opaque_ptr (wv_closure, 0);
    }

  unbind_to (count, Qnil);
  return wv;
}

static widget_value *
menu_item_descriptor_to_widget_value (Lisp_Object desc,
				      int menu_type, /* if this is a menubar,
							popup or sub menu */
				      int deep_p,    /*  */
				      int filter_p)  /* if :filter forms
							should run now */
{
  widget_value *wv;
  int count = specpdl_depth ();
  record_unwind_protect (restore_gc_inhibit,
			 make_int (gc_currently_forbidden));
  gc_currently_forbidden = 1;
  /* Can't GC! */
  wv = menu_item_descriptor_to_widget_value_1 (desc, menu_type, deep_p,
					       filter_p, 0);
  unbind_to (count, Qnil);
  return wv;
}


#if defined LWLIB_MENUBARS_LUCID || defined LWLIB_MENUBARS_MOTIF
int in_menu_callback;

static Lisp_Object
restore_in_menu_callback (Lisp_Object val)
{
  in_menu_callback = XINT (val);
  return Qnil;
}
#endif /* LWLIB_MENUBARS_LUCID || LWLIB_MENUBARS_MOTIF */

#if 0
/* #### Sort of a hack needed to process Vactivate_menubar_hook
   correctly wrt buffer-local values.  A correct solution would
   involve adding a callback mechanism to run_hook().  This function
   is currently unused.  */
static int
my_run_hook (Lisp_Object hooksym, int allow_global_p)
{
  /* This function can GC */
  Lisp_Object tail;
  Lisp_Object value = Fsymbol_value (hooksym);
  int changes = 0;

  if (!NILP (value) && (!CONSP (value) || EQ (XCAR (value), Qlambda)))
    return !EQ (call0 (value), Qt);

  EXTERNAL_LIST_LOOP (tail, value)
    {
      if (allow_global_p && EQ (XCAR (tail), Qt))
	changes |= my_run_hook (Fdefault_value (hooksym), 0);
      if (!EQ (call0 (XCAR (tail)), Qt))
	changes = 1;
    }
  return changes;
}
#endif


/* The order in which callbacks are run is funny to say the least.
   It's sometimes tricky to avoid running a callback twice, and to
   avoid returning prematurely.  So, this function returns true
   if the menu's callbacks are no longer gc protected.  So long
   as we unprotect them before allowing other callbacks to run,
   everything should be ok.

   The pre_activate_callback() *IS* intentionally called multiple times.
   If client_data == NULL, then it's being called before the menu is posted.
   If client_data != NULL, then client_data is a (widget_value *) and
   client_data->data is a Lisp_Object pointing to a lisp submenu description
   that must be converted into widget_values.  *client_data is destructively
   modified.

   #### Stig thinks that there may be a GC problem here due to the
   fact that pre_activate_callback() is called multiple times, but I
   think he's wrong.

   */

static void
pre_activate_callback (Widget widget, LWLIB_ID id, XtPointer client_data)
{
  /* This function can GC */
  struct device *d = get_device_from_display (XtDisplay (widget));
  struct frame *f = x_any_window_to_frame (d, XtWindow (widget));
  Lisp_Object frame;
  int count;

  /* set in lwlib to the time stamp associated with the most recent menu
     operation */
  extern Time x_focus_timestamp_really_sucks_fix_me_better;

  if (!f)
    f = x_any_window_to_frame (d, XtWindow (XtParent (widget)));
  if (!f)
    return;

  /* make sure f is the selected frame */
  XSETFRAME (frame, f);
  Fselect_frame (frame);

  if (client_data)
    {
      /* this is an incremental menu construction callback */
      widget_value *hack_wv = (widget_value *) client_data;
      Lisp_Object submenu_desc;
      widget_value *wv;

      assert (hack_wv->type == INCREMENTAL_TYPE);
      VOID_TO_LISP (submenu_desc, hack_wv->call_data);

      /*
       * #### Fix the menu code so this isn't necessary.
       *
       * Protect against reentering the menu code otherwise we will
       * crash later when the code gets confused at the state
       * changes.
       */
      count = specpdl_depth ();
      record_unwind_protect (restore_in_menu_callback,
			     make_int (in_menu_callback));
      in_menu_callback = 1;
      wv = menu_item_descriptor_to_widget_value (submenu_desc, SUBMENU_TYPE,
						 1, 0);
      unbind_to (count, Qnil);

      if (!wv)
	{
	  wv = xmalloc_widget_value ();
	  wv->type = CASCADE_TYPE;
	  wv->next = NULL;
	  wv->accel = LISP_TO_VOID (Qnil);
	  wv->contents = xmalloc_widget_value ();
	  wv->contents->type = TEXT_TYPE;
	  wv->contents->name = xstrdup ("No menu");
	  wv->contents->next = NULL;
	  wv->contents->accel = LISP_TO_VOID (Qnil);
	}
      assert (wv && wv->type == CASCADE_TYPE && wv->contents);
      replace_widget_value_tree (hack_wv, wv->contents);
      free_popup_widget_value_tree (wv);
    }
  else if (!POPUP_DATAP (FRAME_MENUBAR_DATA (f)))
    return;
  else
    {
#if 0 /* Unused, see comment below. */
      int any_changes;

      /* #### - this menubar update mechanism is expensively anti-social and
	 the activate-menubar-hook is now mostly obsolete. */
      any_changes = my_run_hook (Qactivate_menubar_hook, 1);

      /* #### - It is necessary to *ALWAYS* call set_frame_menubar() now that
	 incremental menus are implemented.  If a subtree of a menu has been
	 updated incrementally (a destructive operation), then that subtree
	 must somehow be wiped.

	 It is difficult to undo the destructive operation in lwlib because
	 a pointer back to lisp data needs to be hidden away somewhere.  So
	 that an INCREMENTAL_TYPE widget_value can be recreated...  Hmmmmm. */
      if (any_changes ||
	  !XFRAME_MENUBAR_DATA (f)->menubar_contents_up_to_date)
	set_frame_menubar (f, 1, 0);
#else
      run_hook (Qactivate_menubar_hook);
      set_frame_menubar (f, 1, 0);
#endif
      DEVICE_X_MOUSE_TIMESTAMP (XDEVICE (FRAME_DEVICE (f))) =
	DEVICE_X_GLOBAL_MOUSE_TIMESTAMP (XDEVICE (FRAME_DEVICE (f))) =
	x_focus_timestamp_really_sucks_fix_me_better;
    }
}

static widget_value *
compute_menubar_data (struct frame *f, Lisp_Object menubar, int deep_p)
{
  if (NILP (menubar))
    return 0;
  else
    {
      widget_value *data;
      int count = specpdl_depth ();

      record_unwind_protect (Fset_buffer, Fcurrent_buffer ());
      Fset_buffer (XWINDOW (FRAME_SELECTED_WINDOW (f))->buffer);
      data = menu_item_descriptor_to_widget_value (menubar, MENUBAR_TYPE,
						   deep_p, 0);
      unbind_to (count, Qnil);

      return data;
    }
}

static int
set_frame_menubar (struct frame *f, int deep_p, int first_time_p)
{
  widget_value *data;
  Lisp_Object menubar;
  int menubar_visible;
  long id;
  /* As with the toolbar, the minibuffer does not have its own menubar. */
  struct window *w = XWINDOW (FRAME_LAST_NONMINIBUF_WINDOW (f));

  if (! FRAME_X_P (f))
    return 0;

  /***** first compute the contents of the menubar *****/

  if (! first_time_p)
    {
      /* evaluate `current-menubar' in the buffer of the selected window
	 of the frame in question. */
      menubar = symbol_value_in_buffer (Qcurrent_menubar, w->buffer);
    }
  else
    {
      /* That's a little tricky the first time since the frame isn't
	 fully initialized yet. */
      menubar = Fsymbol_value (Qcurrent_menubar);
    }

  if (NILP (menubar))
    {
      menubar = Vblank_menubar;
      menubar_visible = 0;
    }
  else
    menubar_visible = !NILP (w->menubar_visible_p);

  data = compute_menubar_data (f, menubar, deep_p);
  if (!data || (!data->next && !data->contents))
    ABORT ();

  if (NILP (FRAME_MENUBAR_DATA (f)))
    {
      struct popup_data *mdata =
	alloc_lcrecord_type (struct popup_data, &lrecord_popup_data);

      mdata->id = new_lwlib_id ();
      mdata->last_menubar_buffer = Qnil;
      mdata->menubar_contents_up_to_date = 0;
      XSETPOPUP_DATA (FRAME_MENUBAR_DATA (f), mdata);
    }

  /***** now store into the menubar widget, creating it if necessary *****/

  id = XFRAME_MENUBAR_DATA (f)->id;
  if (!FRAME_X_MENUBAR_WIDGET (f))
    {
      Widget parent = FRAME_X_CONTAINER_WIDGET (f);

      assert (first_time_p);

      /* It's the first time we've mapped the menubar so compute its
	 contents completely once.  This makes sure that the menubar
	 components are created with the right type. */
      if (!deep_p)
	{
	  free_popup_widget_value_tree (data);
	  data = compute_menubar_data (f, menubar, 1);
	}


      FRAME_X_MENUBAR_WIDGET (f) =
	lw_create_widget ("menubar", "menubar", id, data, parent,
			  0, pre_activate_callback,
			  popup_selection_callback, 0);

    }
  else
    {
      lw_modify_all_widgets (id, data, deep_p ? True : False);
    }
  free_popup_widget_value_tree (data);

  XFRAME_MENUBAR_DATA (f)->menubar_contents_up_to_date = deep_p;
  XFRAME_MENUBAR_DATA (f)->last_menubar_buffer =
    XWINDOW (FRAME_LAST_NONMINIBUF_WINDOW (f))->buffer;
  return menubar_visible;
}


/* Called from x_create_widgets() to create the initial menubar of a frame
   before it is mapped, so that the window is mapped with the menubar already
   there instead of us tacking it on later and thrashing the window after it
   is visible. */
int
x_initialize_frame_menubar (struct frame *f)
{
  return set_frame_menubar (f, 1, 1);
}


static LWLIB_ID last_popup_menu_selection_callback_id;

static void
popup_menu_selection_callback (Widget widget, LWLIB_ID id,
			       XtPointer client_data)
{
  last_popup_menu_selection_callback_id = id;
  popup_selection_callback (widget, id, client_data);
  /* lw_destroy_all_widgets() will be called from popup_down_callback() */
}

static void
popup_menu_down_callback (Widget widget, LWLIB_ID id, XtPointer client_data)
{
  if (popup_handled_p (id))
    return;
  assert (popup_up_p != 0);
  ungcpro_popup_callbacks (id);
  popup_up_p--;
  /* if this isn't called immediately after the selection callback, then
     there wasn't a menu selection. */
  if (id != last_popup_menu_selection_callback_id)
    popup_selection_callback (widget, id, (XtPointer) -1);
  lw_destroy_all_widgets (id);
}


static void
make_dummy_xbutton_event (XEvent *dummy, Widget daddy, Lisp_Event *eev)
     /* NULL for eev means query pointer */
{
  XButtonPressedEvent *btn = (XButtonPressedEvent *) dummy;

  btn->type = ButtonPress;
  btn->serial = 0;
  btn->send_event = 0;
  btn->display = XtDisplay (daddy);
  btn->window = XtWindow (daddy);
  if (eev)
    {
      Position shellx, shelly, framex, framey;
      Arg al [2];
      btn->time = eev->timestamp;
      btn->button = eev->event.button.button;
      btn->root = RootWindowOfScreen (XtScreen (daddy));
      btn->subwindow = (Window) NULL;
      btn->x = eev->event.button.x;
      btn->y = eev->event.button.y;
      shellx = shelly = 0;
#ifndef HAVE_WMCOMMAND
      {
	Widget shell = XtParent (daddy);

	XtSetArg (al [0], XtNx, &shellx);
	XtSetArg (al [1], XtNy, &shelly);
	XtGetValues (shell, al, 2);
      }
#endif
      XtSetArg (al [0], XtNx, &framex);
      XtSetArg (al [1], XtNy, &framey);
      XtGetValues (daddy, al, 2);
      btn->x_root = shellx + framex + btn->x;
      btn->y_root = shelly + framey + btn->y;
      btn->state = ButtonPressMask; /* all buttons pressed */
    }
  else
    {
      /* CurrentTime is just ZERO, so it's worthless for
	 determining relative click times. */
      struct device *d = get_device_from_display (XtDisplay (daddy));
      btn->time = DEVICE_X_MOUSE_TIMESTAMP (d); /* event-Xt maintains this */
      btn->button = 0;
      XQueryPointer (btn->display, btn->window, &btn->root,
		     &btn->subwindow, &btn->x_root, &btn->y_root,
		     &btn->x, &btn->y, &btn->state);
    }
}



static void
x_update_frame_menubar_internal (struct frame *f)
{
  /* We assume the menubar contents has changed if the global flag is set,
     or if the current buffer has changed, or if the menubar has never
     been updated before.
   */
  int menubar_contents_changed =
    (f->menubar_changed
     || NILP (FRAME_MENUBAR_DATA (f))
     || (!EQ (XFRAME_MENUBAR_DATA (f)->last_menubar_buffer,
	      XWINDOW (FRAME_LAST_NONMINIBUF_WINDOW (f))->buffer)));

  Boolean menubar_was_visible = XtIsManaged (FRAME_X_MENUBAR_WIDGET (f));
  Boolean menubar_will_be_visible = menubar_was_visible;
  Boolean menubar_visibility_changed;

  if (menubar_contents_changed)
    menubar_will_be_visible = set_frame_menubar (f, 0, 0);

  menubar_visibility_changed = menubar_was_visible != menubar_will_be_visible;

  if (!menubar_visibility_changed)
    return;

  /* Set menubar visibility */
  (menubar_will_be_visible ? XtManageChild : XtUnmanageChild)
    (FRAME_X_MENUBAR_WIDGET (f));

  MARK_FRAME_SIZE_SLIPPED (f);
}

static void
x_update_frame_menubars (struct frame *f)
{
  assert (FRAME_X_P (f));

  x_update_frame_menubar_internal (f);

  /* #### This isn't going to work right now that this function works on
     a per-frame, not per-device basis.  Guess what?  I don't care. */
}

static void
x_free_frame_menubars (struct frame *f)
{
  Widget menubar_widget;

  assert (FRAME_X_P (f));

  menubar_widget = FRAME_X_MENUBAR_WIDGET (f);
  if (menubar_widget)
    {
      LWLIB_ID id = XFRAME_MENUBAR_DATA (f)->id;
      lw_destroy_all_widgets (id);
      XFRAME_MENUBAR_DATA (f)->id = 0;
    }
}

static void
x_popup_menu (Lisp_Object menu_desc, Lisp_Object event)
{
  int menu_id;
  struct frame *f = selected_frame ();
  widget_value *data;
  Widget parent;
  Widget menu;
  Lisp_Event *eev = NULL;
  XEvent xev;
  Lisp_Object frame;

  XSETFRAME (frame, f);
  CHECK_X_FRAME (frame);
  parent = FRAME_X_SHELL_WIDGET (f);

  if (!NILP (event))
    {
      CHECK_LIVE_EVENT (event);
      eev= XEVENT (event);
      if (eev->event_type != button_press_event
	  && eev->event_type != button_release_event)
	wrong_type_argument (Qmouse_event_p, event);
    }
  else if (!NILP (Vthis_command_keys))
    {
      /* if an event wasn't passed, use the last event of the event sequence
	 currently being executed, if that event is a mouse event */
      eev = XEVENT (Vthis_command_keys); /* last event first */
      if (eev->event_type != button_press_event
	  && eev->event_type != button_release_event)
	eev = NULL;
    }
  make_dummy_xbutton_event (&xev, parent, eev);

  if (SYMBOLP (menu_desc))
    menu_desc = Fsymbol_value (menu_desc);
  CHECK_CONS (menu_desc);
  CHECK_STRING (XCAR (menu_desc));
  data = menu_item_descriptor_to_widget_value (menu_desc, POPUP_TYPE, 1, 1);

  if (! data) error ("no menu");

  menu_id = new_lwlib_id ();
  menu = lw_create_widget ("popup", "popup" /* data->name */, menu_id, data,
			   parent, 1, 0,
			   popup_menu_selection_callback,
			   popup_menu_down_callback);
  free_popup_widget_value_tree (data);

  gcpro_popup_callbacks (menu_id);

  /* Setting zmacs-region-stays is necessary here because executing a command
     from a menu is really a two-command process: the first command (bound to
     the button-click) simply pops up the menu, and returns.  This causes a
     sequence of magic-events (destined for the popup-menu widget) to begin.
     Eventually, a menu item is selected, and a menu-event blip is pushed onto
     the end of the input stream, which is then executed by the event loop.

     So there are two command-events, with a bunch of magic-events between
     them.  We don't want the *first* command event to alter the state of the
     region, so that the region can be available as an argument for the second
     command.
  */
  if (zmacs_regions)
    zmacs_region_stays = 1;

  popup_up_p++;
  lw_popup_menu (menu, &xev);
  /* this speeds up display of pop-up menus */
  XFlush (XtDisplay (parent));
}



#if defined(LWLIB_MENUBARS_LUCID)
static void
menu_move_up (void)
{
  widget_value *current = lw_get_entries (False);
  widget_value *entries = lw_get_entries (True);
  widget_value *prev    = NULL;

  while (entries != current)
    {
      if (entries->name /*&& entries->enabled*/) prev = entries;
      entries = entries->next;
      assert (entries);
    }

  if (!prev)
    /* move to last item */
    {
      while (entries->next)
	{
	  if (entries->name /*&& entries->enabled*/) prev = entries;
	  entries = entries->next;
	}
      if (prev)
	{
	  if (entries->name /*&& entries->enabled*/)
	    prev = entries;
	}
      else
	{
	  /* no selectable items in this menu, pop up to previous level */
	  lw_pop_menu ();
	  return;
	}
    }
  lw_set_item (prev);
}

static void
menu_move_down (void)
{
  widget_value *current = lw_get_entries (False);
  widget_value *new = current;

  while (new->next)
    {
      new = new->next;
      if (new->name /*&& new->enabled*/) break;
    }

  if (new==current||!(new->name/*||new->enabled*/))
    {
      new = lw_get_entries (True);
      while (new!=current)
	{
	  if (new->name /*&& new->enabled*/) break;
	  new = new->next;
	}
      if (new==current&&!(new->name /*|| new->enabled*/))
	{
	  lw_pop_menu ();
	  return;
	}
    }

  lw_set_item (new);
}

static void
menu_move_left (void)
{
  int level = lw_menu_level ();
  int l = level;
  widget_value *current;

  while (level-- >= 3)
    lw_pop_menu ();

  menu_move_up ();
  current = lw_get_entries (False);
  if (l > 2 && current->contents)
    lw_push_menu (current->contents);
}

static void
menu_move_right (void)
{
  int level = lw_menu_level ();
  int l = level;
  widget_value *current;

  while (level-- >= 3)
    lw_pop_menu ();

  menu_move_down ();
  current = lw_get_entries (False);
  if (l > 2 && current->contents)
    lw_push_menu (current->contents);
}

static void
menu_select_item (widget_value *val)
{
  if (val == NULL)
    val = lw_get_entries (False);

  /* is match a submenu? */

  if (val->contents)
    {
      /* enter the submenu */

      lw_set_item (val);
      lw_push_menu (val->contents);
    }
  else
    {
      /* Execute the menu entry by calling the menu's `select'
	 callback function
      */
      lw_kill_menus (val);
    }
}

Lisp_Object
command_builder_operate_menu_accelerator (struct command_builder *builder)
{
  /* this function can GC */

  struct console *con = XCONSOLE (Vselected_console);
  Lisp_Object evee = builder->most_current_event;
  Lisp_Object binding;
  widget_value *entries;

  extern int lw_menu_accelerate; /* lwlib.c */

#if 0
  {
    int i;
    Lisp_Object t;
    char buf[50];

    t = builder->current_events;
    i = 0;
    while (!NILP (t))
      {
	i++;
	sprintf (buf,"OPERATE (%d): ",i);
	write_c_string (buf, Qexternal_debugging_output);
	print_internal (t, Qexternal_debugging_output, 1);
	write_c_string ("\n", Qexternal_debugging_output);
	t = XEVENT_NEXT (t);
      }
  }
#endif /* 0 */

  /* menu accelerator keys don't go into keyboard macros */
  if (!NILP (con->defining_kbd_macro) && NILP (Vexecuting_macro))
    con->kbd_macro_ptr = con->kbd_macro_end;

  /* don't echo menu accelerator keys */
  /*reset_key_echo (builder, 1);*/

  if (!lw_menu_accelerate)
    {
      /* `convert' mouse display to keyboard display
	 by entering the open submenu
      */
      entries = lw_get_entries (False);
      if (entries->contents)
	{
	  lw_push_menu (entries->contents);
	  lw_display_menu (CurrentTime);
	}
    }

  /* compare event to the current menu accelerators */

  entries=lw_get_entries (True);

  while (entries)
    {
      Lisp_Object accel;
      VOID_TO_LISP (accel, entries->accel);
      if (entries->name && !NILP (accel))
	{
	  if (event_matches_key_specifier_p (XEVENT (evee), accel))
	    {
	      /* a match! */

	      menu_select_item (entries);

	      if (lw_menu_active) lw_display_menu (CurrentTime);

	      reset_this_command_keys (Vselected_console, 1);
	      /*reset_command_builder_event_chain (builder);*/
	      return Vmenu_accelerator_map;
	    }
	}
      entries = entries->next;
    }

  /* try to look up event in menu-accelerator-map */

  binding = event_binding_in (evee, Vmenu_accelerator_map, 1);

  if (NILP (binding))
    {
      /* beep at user for undefined key */
      return Qnil;
    }
  else
    {
      if (EQ (binding, Qmenu_quit))
	{
	  /* turn off menus and set quit flag */
	  lw_kill_menus (NULL);
	  Vquit_flag = Qt;
	}
      else if (EQ (binding, Qmenu_up))
	{
	  int level = lw_menu_level ();
	  if (level > 2)
	    menu_move_up ();
	}
      else if (EQ (binding, Qmenu_down))
	{
	  int level = lw_menu_level ();
	  if (level > 2)
	    menu_move_down ();
	  else
	    menu_select_item (NULL);
	}
      else if (EQ (binding, Qmenu_left))
	{
	  int level = lw_menu_level ();
	  if (level > 3)
	    {
	      lw_pop_menu ();
	      lw_display_menu (CurrentTime);
	    }
	  else
	    menu_move_left ();
	}
      else if (EQ (binding, Qmenu_right))
	{
	  int level = lw_menu_level ();
	  if (level > 2 &&
	      lw_get_entries (False)->contents)
	    {
	      widget_value *current = lw_get_entries (False);
	      if (current->contents)
		menu_select_item (NULL);
	    }
	  else
	    menu_move_right ();
	}
      else if (EQ (binding, Qmenu_select))
	menu_select_item (NULL);
      else if (EQ (binding, Qmenu_escape))
	{
	  int level = lw_menu_level ();

	  if (level > 2)
	    {
	      lw_pop_menu ();
	      lw_display_menu (CurrentTime);
	    }
	  else
	    {
	      /* turn off menus quietly */
	      lw_kill_menus (NULL);
	    }
	}
      else if (KEYMAPP (binding))
	{
	  /* prefix key */
	  reset_this_command_keys (Vselected_console, 1);
	  /*reset_command_builder_event_chain (builder);*/
	  return binding;
	}
      else
	{
	  /* turn off menus and execute binding */
	  lw_kill_menus (NULL);
	  reset_this_command_keys (Vselected_console, 1);
	  /*reset_command_builder_event_chain (builder);*/
	  return binding;
	}
    }

  if (lw_menu_active) lw_display_menu (CurrentTime);

  reset_this_command_keys (Vselected_console, 1);
  /*reset_command_builder_event_chain (builder);*/

  return Vmenu_accelerator_map;
}

static Lisp_Object
menu_accelerator_junk_on_error (Lisp_Object errordata, Lisp_Object ignored)
{
  Vmenu_accelerator_prefix    = Qnil;
  Vmenu_accelerator_modifiers = Qnil;
  Vmenu_accelerator_enabled   = Qnil;
  if (!NILP (errordata))
    {
      Lisp_Object args[2];

      args[0] = build_string ("Error in menu accelerators (setting to nil)");
      /* #### This should call
	 (with-output-to-string (display-error errordata))
	 but that stuff is all in Lisp currently. */
      args[1] = errordata;
      warn_when_safe_lispobj
	(Qerror, Qwarning,
	 emacs_doprnt_string_lisp ((const Bufbyte *) "%s: %s",
				   Qnil, -1, 2, args));
    }

  return Qnil;
}

static Lisp_Object
menu_accelerator_safe_compare (Lisp_Object event0)
{
  if (CONSP (Vmenu_accelerator_prefix))
    {
      Lisp_Object t;
      t=Vmenu_accelerator_prefix;
      while (!NILP (t)
	     && !NILP (event0)
	     && event_matches_key_specifier_p (XEVENT (event0), Fcar (t)))
	{
	  t = Fcdr (t);
	  event0 = XEVENT_NEXT (event0);
	}
      if (!NILP (t))
	return Qnil;
    }
  else if (NILP (event0))
    return Qnil;
  else if (event_matches_key_specifier_p (XEVENT (event0), Vmenu_accelerator_prefix))
    event0 = XEVENT_NEXT (event0);
  else
    return Qnil;
  return event0;
}

static Lisp_Object
menu_accelerator_safe_mod_compare (Lisp_Object cons)
{
  return (event_matches_key_specifier_p (XEVENT (XCAR (cons)), XCDR (cons))
	  ? Qt
	  : Qnil);
}

Lisp_Object
command_builder_find_menu_accelerator (struct command_builder *builder)
{
  /* this function can GC */
  Lisp_Object event0 = builder->current_events;
  struct console *con = XCONSOLE (Vselected_console);
  struct frame *f = XFRAME (CONSOLE_SELECTED_FRAME (con));
  Widget menubar_widget;

  /* compare entries in event0 against the menu prefix */

  if ((!CONSOLE_X_P (XCONSOLE (builder->console))) || NILP (event0) ||
      XEVENT (event0)->event_type != key_press_event)
    return Qnil;

  if (!NILP (Vmenu_accelerator_prefix))
    {
      event0 = condition_case_1 (Qerror,
				 menu_accelerator_safe_compare,
				 event0,
				 menu_accelerator_junk_on_error,
				 Qnil);
    }

  if (NILP (event0))
    return Qnil;

  menubar_widget = FRAME_X_MENUBAR_WIDGET (f);
  if (menubar_widget
      && CONSP (Vmenu_accelerator_modifiers))
    {
      Lisp_Object fake = Qnil;
      Lisp_Object last = Qnil;
      struct gcpro gcpro1;
      Lisp_Object matchp;

      widget_value *val;
      LWLIB_ID id = XPOPUP_DATA (f->menubar_data)->id;

      val = lw_get_all_values (id);
      if (val)
	{
	  val = val->contents;

	  fake = Fcopy_sequence (Vmenu_accelerator_modifiers);
	  last = fake;

	  while (!NILP (Fcdr (last)))
	    last = Fcdr (last);

	  Fsetcdr (last, Fcons (Qnil, Qnil));
	  last = Fcdr (last);
	}

      fake = Fcons (Qnil, fake);

      GCPRO1 (fake);

      while (val)
	{
	  Lisp_Object accel;
	  VOID_TO_LISP (accel, val->accel);
	  if (val->name && !NILP (accel))
	    {
	      Fsetcar (last, accel);
	      Fsetcar (fake, event0);
	      matchp = condition_case_1 (Qerror,
					 menu_accelerator_safe_mod_compare,
					 fake,
					 menu_accelerator_junk_on_error,
					 Qnil);
	      if (!NILP (matchp))
		{
		  /* we found one! */

		  lw_set_menu (menubar_widget, val);
		  /* yah - yet another hack.
		     pretend emacs timestamp is the same as an X timestamp,
		     which for the moment it is.  (read events.h)
		     */
		  lw_map_menu (XEVENT (event0)->timestamp);

		  if (val->contents)
		    lw_push_menu (val->contents);

		  lw_display_menu (CurrentTime);

		  /* menu accelerator keys don't go into keyboard macros */
		  if (!NILP (con->defining_kbd_macro)
		      && NILP (Vexecuting_macro))
		    con->kbd_macro_ptr = con->kbd_macro_end;

		  /* don't echo menu accelerator keys */
		  /*reset_key_echo (builder, 1);*/
		  reset_this_command_keys (Vselected_console, 1);
		  UNGCPRO;

		  return Vmenu_accelerator_map;
		}
	    }

	  val = val->next;
	}

      UNGCPRO;
    }
  return Qnil;
}

int
x_kludge_lw_menu_active (void)
{
  return lw_menu_active;
}

DEFUN ("accelerate-menu", Faccelerate_menu, 0, 0, "_", /*
Make the menubar active.  Menu items can be selected using menu accelerators
or by actions defined in menu-accelerator-map.
*/
       ())
{
  struct console *con = XCONSOLE (Vselected_console);
  struct frame *f = XFRAME (CONSOLE_SELECTED_FRAME (con));
  LWLIB_ID id;
  widget_value *val;

  if (NILP (f->menubar_data))
    error ("Frame has no menubar.");

  id = XPOPUP_DATA (f->menubar_data)->id;
  val = lw_get_all_values (id);
  val = val->contents;
  lw_set_menu (FRAME_X_MENUBAR_WIDGET (f), val);
  lw_map_menu (CurrentTime);

  lw_display_menu (CurrentTime);

  /* menu accelerator keys don't go into keyboard macros */
  if (!NILP (con->defining_kbd_macro) && NILP (Vexecuting_macro))
    con->kbd_macro_ptr = con->kbd_macro_end;

  return Qnil;
}
#endif /* LWLIB_MENUBARS_LUCID */


void
syms_of_menubar_x (void)
{
#if defined(LWLIB_MENUBARS_LUCID)
  DEFSUBR (Faccelerate_menu);
#endif
}

void
console_type_create_menubar_x (void)
{
  CONSOLE_HAS_METHOD (x, update_frame_menubars);
  CONSOLE_HAS_METHOD (x, free_frame_menubars);
  CONSOLE_HAS_METHOD (x, popup_menu);
}

void
reinit_vars_of_menubar_x (void)
{
  last_popup_menu_selection_callback_id = (LWLIB_ID) -1;
}

void
vars_of_menubar_x (void)
{
  reinit_vars_of_menubar_x ();

#if defined (LWLIB_MENUBARS_LUCID)
  Fprovide (intern ("lucid-menubars"));
#elif defined (LWLIB_MENUBARS_MOTIF)
  Fprovide (intern ("motif-menubars"));
#elif defined (LWLIB_MENUBARS_ATHENA)
  Fprovide (intern ("athena-menubars"));
#endif
}
