From af46ef3b962b43c23b3b546fcdaef3ca27d843a3 Mon Sep 17 00:00:00 2001
From: Daniel Drake <drake@endlessm.com>
Date: Mon, 6 Jan 2014 13:09:44 -0600
Subject: [PATCH] meta_window_new: clean up error handling

The return code of XGetWindowAttributes() indicates whether an error
was encountered or not. There is no need to specifically check the error
trap.

The trap around XAddToSaveSet() was superfluous. We have a global error
trap to ignore any errors here, and there is no need to XSync() as GDK
will later ignore the error asynchronously if one is raised.

Also move common error exit path to an error label.

https://bugzilla.gnome.org/show_bug.cgi?id=721345
---
 src/core/window.c | 61 ++++++++++++++++-------------------------------
 1 file changed, 20 insertions(+), 41 deletions(-)

diff --git a/src/core/window.c b/src/core/window.c
index 45fdb8cde..db34afe89 100644
--- a/src/core/window.c
+++ b/src/core/window.c
@@ -1440,28 +1440,12 @@ meta_window_new (MetaDisplay       *display,
                                    * creation, to reduce XSync() calls
                                    */
 
-  meta_error_trap_push_with_return (display);
-
-  if (XGetWindowAttributes (display->xdisplay, xwindow, &attrs))
-   {
-      if(meta_error_trap_pop_with_return (display) != Success)
-       {
-          meta_verbose ("Failed to get attributes for window 0x%lx\n",
-                        xwindow);
-          meta_error_trap_pop (display);
-          meta_display_ungrab (display);
-          return NULL;
-       }
-   }
-  else
-   {
-         meta_error_trap_pop_with_return (display);
-         meta_verbose ("Failed to get attributes for window 0x%lx\n",
-                        xwindow);
-         meta_error_trap_pop (display);
-         meta_display_ungrab (display);
-         return NULL;
-   }
+  if (!XGetWindowAttributes (display->xdisplay, xwindow, &attrs))
+    {
+      meta_verbose ("Failed to get attributes for window 0x%lx\n",
+                    xwindow);
+      goto error;
+    }
 
   for (tmp = display->screens; tmp != NULL; tmp = tmp->next)
     {
@@ -1494,17 +1478,13 @@ meta_window_new (MetaDisplay       *display,
       )
      ) {
     meta_verbose ("Not managing our own windows\n");
-    meta_error_trap_pop (display);
-    meta_display_ungrab (display);
-    return NULL;
+    goto error;
   }
 
   if (maybe_filter_xwindow (display, xwindow, must_be_viewable, &attrs))
     {
       meta_verbose ("Not managing filtered window\n");
-      meta_error_trap_pop (display);
-      meta_display_ungrab (display);
-      return NULL;
+      goto error;
     }
 
   existing_wm_state = WithdrawnState;
@@ -1521,9 +1501,7 @@ meta_window_new (MetaDisplay       *display,
             (state == IconicState || state == NormalState)))
         {
           meta_verbose ("Deciding not to manage unmapped or unviewable window 0x%lx\n", xwindow);
-          meta_error_trap_pop (display);
-          meta_display_ungrab (display);
-          return NULL;
+          goto error;
         }
 
       existing_wm_state = state;
@@ -1536,15 +1514,13 @@ meta_window_new (MetaDisplay       *display,
   /*
    * XAddToSaveSet can only be called on windows created by a different
    * client.  with Mutter we want to be able to create manageable windows
-   * from within the process (such as a dummy desktop window), so we do not
-   * want this call failing to prevent the window from being managed -- wrap
-   * it in its own error trap (we use the _with_return() version here to
-   * ensure that XSync() is done on the pop, otherwise the error will not
-   * get caught).
+   * from within the process (such as a dummy desktop window). As we do not
+   * want this call failing to prevent the window from being managed, we
+   * call this before creating the return-checked error trap.
    */
-  meta_error_trap_push_with_return (display);
   XAddToSaveSet (display->xdisplay, xwindow);
-  meta_error_trap_pop_with_return (display);
+
+  meta_error_trap_push_with_return (display);
 
   event_mask = PropertyChangeMask | ColormapChangeMask;
   if (attrs.override_redirect)
@@ -1591,9 +1567,7 @@ meta_window_new (MetaDisplay       *display,
     {
       meta_verbose ("Window 0x%lx disappeared just as we tried to manage it\n",
                     xwindow);
-      meta_error_trap_pop (display);
-      meta_display_ungrab (display);
-      return NULL;
+      goto error;
     }
 
   window = meta_window_new_shared (display,
@@ -1617,6 +1591,11 @@ meta_window_new (MetaDisplay       *display,
   display_notify_window (display, window);
 
   return window;
+
+error:
+  meta_error_trap_pop (display);
+  meta_display_ungrab (display);
+  return NULL;
 }
 
 /* This function should only be called from the end of meta_window_new_with_attrs () */