sqlalchemy.util.queue

An adaptation of Py2.3/2.4's Queue module which supports reentrant behavior, using RLock instead of Lock for its mutex object. The Queue object is used exclusively by the sqlalchemy.pool.QueuePool class. This is to support the connection pool's usage of weakref callbacks to return connections to the underlying Queue, which can in extremely rare cases be invoked within the ``get()`` method of the Queue itself, producing a ``put()`` inside the ``get()`` and therefore a reentrant condition.