[gtk+] Don't assume a screen exists before realize()

[Matthias Clasen <matthiasc src gnome org>]

commit 4dc9b294d8a5bd822828964930b834f4b8999cff
Author: Matthias Clasen <mclasen redhat com>
Date:   Fri Feb 4 22:01:40 2011 -0500

    Don't assume a screen exists before realize()
    
    Fix for https://bugzilla.gnome.org/show_bug.cgi?id=641429

 gtk/gtkstyle.c        |    9 +++++----
 gtk/gtkstylecontext.c |    2 +-
 gtk/gtkwidget.c       |    2 +-
 gtk/gtkwindow.c       |   20 +++++++++++---------
 4 files changed, 18 insertions(+), 15 deletions(-)
---
diff --git a/gtk/gtkstyle.c b/gtk/gtkstyle.c
index 81105d8..5347119 100644
--- a/gtk/gtkstyle.c
+++ b/gtk/gtkstyle.c
@@ -813,13 +813,15 @@ gtk_style_copy (GtkStyle *style)
 
 GtkStyle*
 _gtk_style_new_for_path (GdkScreen     *screen,
-			 GtkWidgetPath *path)
+                         GtkWidgetPath *path)
 {
   GtkStyleContext *context;
   GtkStyle *style;
 
   context = gtk_style_context_new ();
-  gtk_style_context_set_screen (context, screen);
+
+  if (screen)
+    gtk_style_context_set_screen (context, screen);
   gtk_style_context_set_path (context, path);
 
   style = g_object_new (GTK_TYPE_STYLE,
@@ -848,8 +850,7 @@ gtk_style_new (void)
   path = gtk_widget_path_new ();
   gtk_widget_path_append_type (path, GTK_TYPE_WIDGET);
 
-  style = _gtk_style_new_for_path (gdk_screen_get_default (),
-				   path);
+  style = _gtk_style_new_for_path (gdk_screen_get_default (), path);
 
   gtk_widget_path_free (path);
 
diff --git a/gtk/gtkstylecontext.c b/gtk/gtkstylecontext.c
index 7cd0dab..6eed378 100644
--- a/gtk/gtkstylecontext.c
+++ b/gtk/gtkstylecontext.c
@@ -2617,7 +2617,7 @@ gtk_style_context_set_screen (GtkStyleContext *context,
   GtkStyleContextPrivate *priv;
 
   g_return_if_fail (GTK_IS_STYLE_CONTEXT (context));
-  g_return_if_fail (GDK_IS_SCREEN (screen));
+  g_return_if_fail (screen == NULL || GDK_IS_SCREEN (screen));
 
   priv = context->priv;
   if (priv->screen == screen)
diff --git a/gtk/gtkwidget.c b/gtk/gtkwidget.c
index 74d83f2..f7e5383 100644
--- a/gtk/gtkwidget.c
+++ b/gtk/gtkwidget.c
@@ -14179,7 +14179,7 @@ gtk_widget_get_style_context (GtkWidget *widget)
                         G_CALLBACK (style_context_changed), widget);
 
       gtk_style_context_set_screen (widget->priv->context,
-                                    gtk_widget_get_screen (widget));
+                                    gtk_widget_get_screen_unchecked (widget));
 
       _gtk_widget_update_path (widget);
       gtk_style_context_set_path (widget->priv->context,
diff --git a/gtk/gtkwindow.c b/gtk/gtkwindow.c
index 5696c19..7336d02 100644
--- a/gtk/gtkwindow.c
+++ b/gtk/gtkwindow.c
@@ -1108,8 +1108,9 @@ gtk_window_init (GtkWindow *window)
   priv->has_user_ref_count = TRUE;
   toplevel_list = g_slist_prepend (toplevel_list, window);
 
-  g_signal_connect (priv->screen, "composited-changed",
-		    G_CALLBACK (gtk_window_on_composited_changed), window);
+  if (priv->screen)
+    g_signal_connect (priv->screen, "composited-changed",
+                      G_CALLBACK (gtk_window_on_composited_changed), window);
 }
 
 static void
@@ -7961,7 +7962,7 @@ gtk_window_set_screen (GtkWindow *window,
   GtkWidget *widget;
   GdkScreen *previous_screen;
   gboolean was_mapped;
-  
+
   g_return_if_fail (GTK_IS_WINDOW (window));
   g_return_if_fail (GDK_IS_SCREEN (screen));
 
@@ -7979,17 +7980,18 @@ gtk_window_set_screen (GtkWindow *window,
     gtk_widget_unmap (widget);
   if (gtk_widget_get_realized (widget))
     gtk_widget_unrealize (widget);
-      
+
   gtk_window_free_key_hash (window);
   priv->screen = screen;
   gtk_widget_reset_rc_styles (widget);
   if (screen != previous_screen)
     {
-      g_signal_handlers_disconnect_by_func (previous_screen,
-					    gtk_window_on_composited_changed, window);
-      g_signal_connect (screen, "composited-changed", 
-			G_CALLBACK (gtk_window_on_composited_changed), window);
-      
+      if (previous_screen)
+        g_signal_handlers_disconnect_by_func (previous_screen,
+                                              gtk_window_on_composited_changed, window);
+      g_signal_connect (screen, "composited-changed",
+                        G_CALLBACK (gtk_window_on_composited_changed), window);
+
       _gtk_widget_propagate_screen_changed (widget, previous_screen);
       _gtk_widget_propagate_composited_changed (widget);
     }