x11: Make selection handling work across screens

When dealing with selection events, we might see windows from
other screens in the requestor field. The current x11 backend
code fails to wrap these in a foreign GdkWindow, since we
don't have the corresponding GdkScreen anymore. Work around
this by creating such 'foreign screens' on demand. We still
maintain the 1:1 relation between the display and the screen
returned by gdk_display_get_default_screen().

https://bugzilla.gnome.org/show_bug.cgi?id=721398

diff --git a/gdk/x11/gdkdisplay-x11.c b/gdk/x11/gdkdisplay-x11.c
index f2824b65bd75cb1e56a1064cce71e3bcc3354483..9bb27eecfb110150c4be937188c59f5e40c39553 100644 (file)
--- a/gdk/x11/gdkdisplay-x11.c
+++ b/gdk/x11/gdkdisplay-x11.c
@@ -1959,6 +1959,7 @@ gdk_x11_display_finalize (GObject *object)
 
   /* Free all GdkScreens */
   g_object_unref (display_x11->screen);
+  g_list_free_full (display_x11->screens, g_object_unref);
 
   g_free (display_x11->startup_notification_id);
 
@@ -2035,12 +2036,36 @@ GdkScreen *
 _gdk_x11_display_screen_for_xrootwin (GdkDisplay *display,
                                      Window      xrootwin)
 {
-  GdkScreen *screen = gdk_display_get_default_screen (display);
+  GdkScreen *screen;
+  XWindowAttributes attrs;
+  gboolean result;
+  GdkX11Display *display_x11;
+  GList *l;
+
+  screen = gdk_display_get_default_screen (display);
 
   if (GDK_SCREEN_XROOTWIN (screen) == xrootwin)
     return screen;
 
-  return NULL;
+  display_x11 = GDK_X11_DISPLAY (display);
+
+  for (l = display_x11->screens; l; l = l->next)
+    {
+      screen = l->data;
+      if (GDK_SCREEN_XROOTWIN (screen) == xrootwin)
+        return screen;
+    }
+
+  gdk_x11_display_error_trap_push (display);
+  result = XGetWindowAttributes (display_x11->xdisplay, xrootwin, &attrs);
+  if (gdk_x11_display_error_trap_pop (display) || !result)
+    return NULL;
+
+  screen = _gdk_x11_screen_new (display, XScreenNumberOfScreen (attrs.screen));
+
+  display_x11->screens = g_list_prepend (display_x11->screens, screen);
+
+  return screen;
 }
 
 /**

diff --git a/gdk/x11/gdkdisplay-x11.h b/gdk/x11/gdkdisplay-x11.h
index aadf255ba6dda8a915ea74a23566bb9e3fef1883..9b78f61d17cc544964786db768ebdd648bc679bd 100644 (file)
--- a/gdk/x11/gdkdisplay-x11.h
+++ b/gdk/x11/gdkdisplay-x11.h
@@ -39,6 +39,7 @@ struct _GdkX11Display
   GdkDisplay parent_instance;
   Display *xdisplay;
   GdkScreen *screen;
+  GList *screens;
 
   GSource *event_source;