Merge lp:~unity-team/compiz/trunk.fix_758307 into lp:~unity-team/compiz/trunk

[Sam Spilsbury]

Check the return value of XQueryTree which determines if the parent window == the root window to ensure that it actually succeeded, since if it didn't then children is going to be an invalid pointer and freeing those is always bad. Fixes LP #758307

[David Barth (dbarth)]

review: Approve

=== modified file 'src/window.cpp'
--- src/window.cpp	2011-04-08 11:40:39 +0000
+++ src/window.cpp	2011-04-12 12:28:26 +0000
@@ -5689,6 +5689,7 @@
 						  screen->screenNum ());
     Colormap		 cmap = DefaultColormap (screen->dpy (),
 						 screen->screenNum ());
+    bool success = false;
 
     if (frame || attrib.override_redirect)
 	return false;
@@ -5700,17 +5701,22 @@
      * reparented themselves on the server side but not
      * on the client side */
 
-    XQueryTree (dpy, id, &root_return, &parent_return, &children, &nchildren);
-
-    if (parent_return != root_return)
-    {
-	XFree (children);
-	XUngrabServer (dpy);
-	XSync (dpy, false);
-	return false;
-    }
-
-    if (!XGetWindowAttributes (dpy, id, &wa))
+    success = XQueryTree (dpy, id, &root_return,
+		          &parent_return, &children, &nchildren);
+
+    if (success && parent_return != root_return)
+    {
+	success = false;
+	XFree (children);
+    }
+
+    if (success && !XGetWindowAttributes (dpy, id, &wa))
+    {
+	success = false;
+	XFree (children);
+    }
+
+    if (!success)
     {
 	XUngrabServer (dpy);
 	XSync (dpy, false);