Subject: 23.3.50; y-or-n-p-with-timeout with GUI leaks memory
From: YAMAMOTO Mitsuharu <[email-masked]>
To: [email-masked]
Date: Sat, 22 Oct 2011 13:35:27 +0900
List-Id: <debbugs-submit.debbugs.gnu.org>

Currently, xdialog_show in xmenu.c calls
free_menubar_widget_value_tree after calling create_and_show_dialog:

  /* Actually create and show the dialog.  */
  create_and_show_dialog (f, first_wv);

  /* Free the widget_value objects we used to specify the contents.  */
  free_menubar_widget_value_tree (first_wv);

But create_and_show_dialog may longjmp in the following case:

  (let (last-nonmenu-event)
    (y-or-n-p-with-timeout "test" 3 'default))
  ;; wait 3 seconds.

In this case, free_menubar_widget_value_tree is not called and the
memory allocated for `first_wv' is leaked.

The patch below uses record_unwind_protect as usual for avoiding this
memory leak.  I think xmenu_show has the same problem.  I'm not sure
about the W32 case.

				     YAMAMOTO Mitsuharu
				[email-masked]

=== modified file 'src/xmenu.c'
*** src/xmenu.c	2011-05-09 11:13:02 +0000
--- src/xmenu.c	2011-10-22 02:14:19 +0000
***************
*** 1658,1663 ****
--- 1658,1674 ----
  
  #endif /* not USE_GTK */
  
+ static Lisp_Object
+ cleanup_widget_value_tree (Lisp_Object arg)
+ {
+   struct Lisp_Save_Value *p = XSAVE_VALUE (arg);
+   widget_value *wv = p->pointer;
+ 
+   free_menubar_widget_value_tree (wv);
+ 
+   return Qnil;
+ }
+ 
  Lisp_Object
  xmenu_show (FRAME_PTR f, int x, int y, int for_click, int keymaps,
  	    Lisp_Object title, char **error, EMACS_UINT timestamp)
***************
*** 1672,1677 ****
--- 1683,1690 ----
  
    int first_pane;
  
+   int specpdl_count = SPECPDL_INDEX ();
+ 
    if (! FRAME_X_P (f))
      abort ();
  
***************
*** 1866,1876 ****
    /* No selection has been chosen yet.  */
    menu_item_selection = 0;
  
    /* Actually create and show the menu until popped down.  */
    create_and_show_popup_menu (f, first_wv, x, y, for_click, timestamp);
  
!   /* Free the widget_value objects we used to specify the contents.  */
!   free_menubar_widget_value_tree (first_wv);
  
    /* Find the selected item, and its pane, to return
       the proper value.  */
--- 1879,1893 ----
    /* No selection has been chosen yet.  */
    menu_item_selection = 0;
  
+   /* Make sure to free the widget_value objects we used to specify the
+      contents even with longjmp.  */
+   record_unwind_protect (cleanup_widget_value_tree,
+ 			 make_save_value (first_wv, 0));
+ 
    /* Actually create and show the menu until popped down.  */
    create_and_show_popup_menu (f, first_wv, x, y, for_click, timestamp);
  
!   unbind_to (specpdl_count, Qnil);
  
    /* Find the selected item, and its pane, to return
       the proper value.  */
***************
*** 2064,2069 ****
--- 2081,2088 ----
    /* 1 means we've seen the boundary between left-hand elts and right-hand.  */
    int boundary_seen = 0;
  
+   int specpdl_count = SPECPDL_INDEX ();
+ 
    if (! FRAME_X_P (f))
      abort ();
  
***************
*** 2177,2187 ****
    /* No selection has been chosen yet.  */
    menu_item_selection = 0;
  
    /* Actually create and show the dialog.  */
    create_and_show_dialog (f, first_wv);
  
!   /* Free the widget_value objects we used to specify the contents.  */
!   free_menubar_widget_value_tree (first_wv);
  
    /* Find the selected item, and its pane, to return
       the proper value.  */
--- 2196,2210 ----
    /* No selection has been chosen yet.  */
    menu_item_selection = 0;
  
+   /* Make sure to free the widget_value objects we used to specify the
+      contents even with longjmp.  */
+   record_unwind_protect (cleanup_widget_value_tree,
+ 			 make_save_value (first_wv, 0));
+ 
    /* Actually create and show the dialog.  */
    create_and_show_dialog (f, first_wv);
  
!   unbind_to (specpdl_count, Qnil);
  
    /* Find the selected item, and its pane, to return
       the proper value.  */

In GNU Emacs 23.3.50.1 (x86_64-apple-darwin10.8.0, GTK+ Version 2.24.6)
 of 2011-10-20 on yamamoto-mitsuharu-no-iMac.local
Windowing system distributor `The X.Org Foundation', version 11.0.10402000
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