g_mutex_lock (priv->queue_lock);
g_queue_foreach (priv->op_queue, (GFunc) on_find_by_source_foreach, info);
g_mutex_unlock (priv->queue_lock);
g_mutex_lock (priv->queue_lock);
g_queue_foreach (priv->op_queue, (GFunc) on_find_by_source_foreach, info);
g_mutex_unlock (priv->queue_lock);