x11: Introduce _gdk_x11_get_xatom_for_display_printf()

and use it instead of caching the atom in the GdkScreenX11.

gdk/x11/gdkprivate-x11.h

@@ -297,6 +297,10 @@ void _gdk_x11_precache_atoms (GdkDisplay          *display,
                               const gchar * const *atom_names,
                               gint                 n_atoms);
 
+Atom _gdk_x11_get_xatom_for_display_printf         (GdkDisplay    *display,
+                                                    const gchar   *format,
+                                                    ...) G_GNUC_PRINTF (2, 3);
+
 GdkFilterReturn
 _gdk_x11_dnd_filter (GdkXEvent *xev,
                      GdkEvent  *event,

gdk/x11/gdkproperty-x11.c

@@ -461,6 +461,26 @@ gdk_x11_get_xatom_by_name_for_display (GdkDisplay  *display,
 					    gdk_atom_intern (atom_name, FALSE));
 }
 
+Atom
+_gdk_x11_get_xatom_for_display_printf (GdkDisplay    *display,
+                                       const gchar   *format,
+                                       ...)
+{
+  va_list args;
+  char *atom_name;
+  Atom atom;
+
+  va_start (args, format);
+  atom_name = g_strdup_vprintf (format, args);
+  va_end (args);
+
+  atom = gdk_x11_get_xatom_by_name_for_display (display, atom_name);
+
+  g_free (atom_name);
+
+  return atom;
+}
+
 /**
  * gdk_x11_get_xatom_by_name:
  * @atom_name: a string

gdk/x11/gdkscreen-x11.c

@@ -434,27 +434,23 @@ gdk_x11_screen_get_screen_number (GdkScreen *screen)
   return GDK_X11_SCREEN (screen)->screen_num;
 }
 
+static Atom
+get_cm_atom (GdkX11Screen *x11_screen)
+{
+  return _gdk_x11_get_xatom_for_display_printf (x11_screen->display, "_NET_WM_CM_S%d", x11_screen->screen_num);
+}
+
 static gboolean
 check_is_composited (GdkDisplay *display,
 		     GdkX11Screen *x11_screen)
 {
-  Atom xselection = gdk_x11_atom_to_xatom_for_display (display, x11_screen->cm_selection_atom);
   Window xwindow;
   
-  xwindow = XGetSelectionOwner (GDK_DISPLAY_XDISPLAY (display), xselection);
+  xwindow = XGetSelectionOwner (GDK_DISPLAY_XDISPLAY (display), get_cm_atom (x11_screen));
 
   return xwindow != None;
 }
 
-static GdkAtom
-make_cm_atom (int screen_number)
-{
-  gchar *name = g_strdup_printf ("_NET_WM_CM_S%d", screen_number);
-  GdkAtom atom = gdk_atom_intern (name, FALSE);
-  g_free (name);
-  return atom;
-}
-
 static void
 init_monitor_geometry (GdkX11Monitor *monitor,
 		       int x, int y, int width, int height)
@@ -1076,9 +1072,8 @@ _gdk_x11_screen_setup (GdkScreen *screen)
 {
   GdkX11Screen *x11_screen = GDK_X11_SCREEN (screen);
 
-  x11_screen->cm_selection_atom = make_cm_atom (x11_screen->screen_num);
   gdk_display_request_selection_notification (x11_screen->display,
-					      x11_screen->cm_selection_atom);
+					      gdk_x11_xatom_to_atom_for_display (x11_screen->display, get_cm_atom (x11_screen)));
   x11_screen->is_composited = check_is_composited (x11_screen->display, x11_screen);
 }
 
@@ -1194,10 +1189,8 @@ _gdk_x11_screen_process_owner_change (GdkScreen *screen,
 #ifdef HAVE_XFIXES
   XFixesSelectionNotifyEvent *selection_event = (XFixesSelectionNotifyEvent *)event;
   GdkX11Screen *x11_screen = GDK_X11_SCREEN (screen);
-  Atom xcm_selection_atom = gdk_x11_atom_to_xatom_for_display (x11_screen->display,
-							       x11_screen->cm_selection_atom);
 
-  if (selection_event->selection == xcm_selection_atom)
+  if (selection_event->selection == get_cm_atom (x11_screen))
     {
       gboolean composited = selection_event->owner != None;
 

gdk/x11/gdkscreen-x11.h

@@ -56,7 +56,6 @@ struct _GdkX11Screen
   gint xft_dpi;
 
   /* Window manager */
-  GdkAtom cm_selection_atom;
   long last_wmspec_check_time;
   Window wmspec_check_window;
   char *window_manager_name;