Fix a critical when processing deferred messages

Due to GMainContext manipulations and reentrancy issues, it's
possible the source pointer is NULL inside the callback.
Let's avoid the critical warning by unreffing the source early
- it is kept alive by GMainContext anyway after the attach.

https://bugzilla.gnome.org/show_bug.cgi?id=724292

diff --git a/atspi/atspi-misc.c b/atspi/atspi-misc.c
index 28de86f..48dd063 100644 (file)
--- a/atspi/atspi-misc.c
+++ b/atspi/atspi-misc.c
@@ -747,7 +747,6 @@ process_deferred_messages_callback (gpointer data)
   if (process_deferred_messages ())
     return G_SOURCE_CONTINUE;
 
-  g_source_unref (process_deferred_messages_source);
   process_deferred_messages_source = NULL;
   return G_SOURCE_REMOVE;
 }
@@ -769,6 +768,7 @@ defer_message (DBusConnection *connection, DBusMessage *message, void *user_data
     g_source_set_callback (process_deferred_messages_source,
                            process_deferred_messages_callback, NULL, NULL);
     g_source_attach (process_deferred_messages_source, atspi_main_context);
+    g_source_unref (process_deferred_messages_source);
   }
 
   return DBUS_HANDLER_RESULT_HANDLED;
@@ -1608,9 +1608,9 @@ atspi_set_timeout (gint val, gint startup_time)
   app_startup_time = startup_time;
 }
 
-/*
+/**
  * atspi_set_main_context:
- * @cnx: The #GmainContext to use.
+ * @cnx: The #GMainContext to use.
  *
  * Sets the main loop context that AT-SPI should assume is in use when
  * setting an idle callback.
@@ -1625,11 +1625,11 @@ atspi_set_main_context (GMainContext *cnx)
   if (process_deferred_messages_source != NULL)
   {
     g_source_destroy (process_deferred_messages_source);
-    g_source_unref (process_deferred_messages_source);
     process_deferred_messages_source = g_idle_source_new ();
     g_source_set_callback (process_deferred_messages_source,
                            process_deferred_messages_callback, NULL, NULL);
     g_source_attach (process_deferred_messages_source, cnx);
+    g_source_unref (process_deferred_messages_source);
   }
   atspi_main_context = cnx;
   atspi_dbus_connection_setup_with_g_main (atspi_get_a11y_bus (), cnx);