gdbus: Fix removal of filter after last filter_data

If there's a signal watch that's also watching for name
(data->name_watch) currently we are trying to remove the message_filter
twice since we may have the following call chain:

filter_data_remove_callback()
  filter_data_free()
    g_dbus_remove_watch()
      filter_data_remove_callback()
	filter_data_free()
        dbus_connection_remove_filter()
  dbus_connection_remove_filter()

Because of this we can't currently watch for signals passing the bus
name. After this patch we don't have this issue anymore.

We fix it by removing the filter before calling filter_data_free() if we
are the last filter_data and thus avoid calling
dbus_connection_remove_filter() twice.

diff --git a/gdbus/watch.c b/gdbus/watch.c
index 9a716b0..d749176 100644 (file)
--- a/gdbus/watch.c
+++ b/gdbus/watch.c
@@ -376,15 +376,14 @@ static gboolean filter_data_remove_callback(struct filter_data *data,
 
        connection = dbus_connection_ref(data->connection);
        listeners = g_slist_remove(listeners, data);
-       filter_data_free(data);
 
        /* Remove filter if there are no listeners left for the connection */
-       data = filter_data_find(connection, NULL, NULL, NULL, NULL, NULL,
-                                       NULL);
-       if (data == NULL)
+       if (filter_data_find(connection, NULL, NULL, NULL, NULL, NULL,
+                                                               NULL) == NULL)
                dbus_connection_remove_filter(connection, message_filter,
                                                NULL);
 
+       filter_data_free(data);
        dbus_connection_unref(connection);
 
        return TRUE;
@@ -537,15 +536,15 @@ static DBusHandlerResult message_filter(DBusConnection *connection,
        remove_match(data);
 
        listeners = g_slist_remove(listeners, data);
-       filter_data_free(data);
 
-       /* Remove filter if there no listener left for the connection */
-       data = filter_data_find(connection, NULL, NULL, NULL, NULL, NULL,
-                                       NULL);
-       if (data == NULL)
+       /* Remove filter if there are no listeners left for the connection */
+       if (filter_data_find(connection, NULL, NULL, NULL, NULL, NULL,
+                                                               NULL) == NULL)
                dbus_connection_remove_filter(connection, message_filter,
                                                NULL);
 
+       filter_data_free(data);
+
        return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
 }