Class DataFlowReentrantGuard

tensorpack/dataflow/base.py:24–40

A tool to enforce non-reentrancy. Mostly used on DataFlow whose :meth:`get_data` is stateful, so that multiple instances of the iterator cannot co-exist.

class DataFlowReentrantGuard(object):
    """
    A tool to enforce non-reentrancy.
    Mostly used on DataFlow whose :meth:`get_data` is stateful,
    so that multiple instances of the iterator cannot co-exist.
    """
    def __init__(self):
        self._lock = threading.Lock()

    def __enter__(self):
        self._succ = self._lock.acquire(False)
        if not self._succ:
            raise threading.ThreadError("This DataFlow is not reentrant!")

    def __exit__(self, exc_type, exc_val, exc_tb):
        self._lock.release()
        return False


class DataFlowMeta(ABCMeta):