handle NULL screen from screen_for_xwindow

2002-07-23  Havoc Pennington  <hp@redhat.com>

	* src/keybindings.c (meta_display_process_key_event): handle
	NULL screen from screen_for_xwindow

	* src/display.c (meta_display_screen_for_xwindow): put an error
	trap around the XGetWindowAttributes(), should fix the popular
	"closing a window results in a crash" bug.

	* src/util.c (print_backtrace): support optional backtrace
	feature using gnu libc backtrace() call

ChangeLog

@@ -1,3 +1,15 @@
+2002-07-23  Havoc Pennington  <hp@redhat.com>
+
+	* src/keybindings.c (meta_display_process_key_event): handle 
+	NULL screen from screen_for_xwindow
+
+	* src/display.c (meta_display_screen_for_xwindow): put an error
+	trap around the XGetWindowAttributes(), should fix the popular 
+	"closing a window results in a crash" bug.
+
+	* src/util.c (print_backtrace): support optional backtrace
+	feature using gnu libc backtrace() call
+
 2002-07-15  jacob berkman  <jacob@ximian.com>
 
 	* src/update-from-egg.sh: steal from profterm to fix build

configure.in

@@ -82,6 +82,11 @@ if test "x$GCC" = "xyes"; then
 fi
 changequote([,])dnl
 
+
+## try definining HAVE_BACKTRACE
+AC_CHECK_HEADERS(execinfo.h, [AC_CHECK_FUNCS(backtrace)])
+
+
 ALL_LINGUAS="az ca da de es fr gl it ja ko lv ms no pl pt ru sk sv tr uk zh_TW"
 AM_GLIB_GNU_GETTEXT
 

src/core.c

@@ -525,6 +525,8 @@ meta_core_begin_grab_op (Display    *xdisplay,
   screen = meta_display_screen_for_xwindow (display, frame_xwindow);
   window = meta_display_lookup_x_window (display, frame_xwindow);
 
+  g_assert (screen != NULL);
+  
   if (window == NULL || window->frame == NULL)
     meta_bug ("No such frame window 0x%lx!\n", frame_xwindow);  
 

src/display.c

@@ -640,8 +640,11 @@ meta_display_screen_for_xwindow (MetaDisplay *display,
 {
   XWindowAttributes attr;
 
+  meta_error_trap_push (display);
   XGetWindowAttributes (display->xdisplay, xwindow, &attr);
-
+  if (meta_error_trap_pop (display) != Success)
+    return NULL;
+  
   return meta_display_screen_for_x_screen (display, attr.screen);
 }
 

src/keybindings.c

@@ -1273,6 +1273,9 @@ meta_display_process_key_event (MetaDisplay *display,
   screen = meta_display_screen_for_xwindow (display,
                                             event->xany.window);
 
+  if (screen == NULL)
+    return; /* event window is destroyed */
+  
   /* window may be NULL */  
   
   keysym = XKeycodeToKeysym (display->xdisplay, event->xkey.keycode, 0);

src/util.c

@@ -29,6 +29,37 @@
 #include <errno.h>
 #include <string.h>
 
+#ifdef HAVE_BACKTRACE
+#include <execinfo.h>
+static void
+print_backtrace (void)
+{
+  void *bt[500];
+  int bt_size;
+  int i;
+  char **syms;
+  
+  bt_size = backtrace (bt, 500);
+
+  syms = backtrace_symbols (bt, bt_size);
+  
+  i = 0;
+  while (i < bt_size)
+    {
+      meta_verbose ("  %s\n", syms[i]);
+      ++i;
+    }
+
+  free (syms);
+}
+#else
+static void
+print_backtrace (void)
+{
+  meta_verbose ("Not compiled with backtrace support\n");
+}
+#endif
+
 static gboolean is_verbose = FALSE;
 static gboolean is_debugging = FALSE;
 static gboolean replace_current = FALSE;
@@ -264,6 +295,8 @@ meta_bug (const char *format, ...)
   
   g_free (str);
 
+  print_backtrace ();
+  
   /* stop us in a debugger */
   abort ();
 }