gtk(gl)sink: remove the signal handlers on finalize

It's possible that the sink element will be freed before the widget is
destroyed.  When the widget was eventually destroyed, it was attempting to
access member variables of the freed sink struct which resulted in undefined
behaviour.

Fix by disconnecting our signal on finalize.

https://bugzilla.gnome.org/show_bug.cgi?id=762098

diff --git a/ext/gtk/gstgtkbasesink.c b/ext/gtk/gstgtkbasesink.c
index e192940..f0019bf 100644 (file)
--- a/ext/gtk/gstgtkbasesink.c
+++ b/ext/gtk/gstgtkbasesink.c
@@ -141,9 +141,16 @@ gst_gtk_base_sink_init (GstGtkBaseSink * gtk_sink)
 static void
 gst_gtk_base_sink_finalize (GObject * object)
 {
-  GstGtkBaseSink *gtk_sink = GST_GTK_BASE_SINK (object);;
+  GstGtkBaseSink *gtk_sink = GST_GTK_BASE_SINK (object);
+
+  GST_OBJECT_LOCK (gtk_sink);
+  if (gtk_sink->window && gtk_sink->window_destroy_id)
+    g_signal_handler_disconnect (gtk_sink->window, gtk_sink->window_destroy_id);
+  if (gtk_sink->widget && gtk_sink->widget_destroy_id)
+    g_signal_handler_disconnect (gtk_sink->widget, gtk_sink->widget_destroy_id);
 
   g_clear_object (&gtk_sink->widget);
+  GST_OBJECT_UNLOCK (gtk_sink);
 
   G_OBJECT_CLASS (parent_class)->finalize (object);
 }
@@ -194,7 +201,7 @@ gst_gtk_base_sink_get_widget (GstGtkBaseSink * gtk_sink)
   /* Take the floating ref, other wise the destruction of the container will
    * make this widget disapear possibly before we are done. */
   gst_object_ref_sink (gtk_sink->widget);
-  g_signal_connect (gtk_sink->widget, "destroy",
+  gtk_sink->widget_destroy_id = g_signal_connect (gtk_sink->widget, "destroy",
       G_CALLBACK (widget_destroy_cb), gtk_sink);
 
   /* back pointer */
@@ -316,7 +323,7 @@ gst_gtk_base_sink_start_on_main (GstBaseSink * bsink)
     gtk_window_set_default_size (GTK_WINDOW (gst_sink->window), 640, 480);
     gtk_window_set_title (GTK_WINDOW (gst_sink->window), klass->window_title);
     gtk_container_add (GTK_CONTAINER (gst_sink->window), toplevel);
-    g_signal_connect (gst_sink->window, "destroy",
+    gst_sink->window_destroy_id = g_signal_connect (gst_sink->window, "destroy",
         G_CALLBACK (window_destroy_cb), gst_sink);
   }
 

diff --git a/ext/gtk/gstgtkbasesink.h b/ext/gtk/gstgtkbasesink.h
index 7260cd5..ef8c284 100644 (file)
--- a/ext/gtk/gstgtkbasesink.h
+++ b/ext/gtk/gstgtkbasesink.h
@@ -69,6 +69,8 @@ struct _GstGtkBaseSink
   GBinding             *bind_ignore_alpha;
 
   GtkWidget            *window;
+  gulong               widget_destroy_id;
+  gulong               window_destroy_id;
 };
 
 /**