codekingpro/portable-devtools

1from eventlet import hubs2from eventlet.semaphore import Semaphore3 4 5class Lock(Semaphore):6 7    """A lock.8    This is API-compatible with :class:`threading.Lock`.9 10    It is a context manager, and thus can be used in a with block::11 12      lock = Lock()13      with lock:14        do_some_stuff()15    """16 17    def release(self, blocking=True):18        """Modify behaviour vs :class:`Semaphore` to raise a RuntimeError19        exception if the value is greater than zero. This corrects behaviour20        to realign with :class:`threading.Lock`.21        """22        if self.counter > 0:23            raise RuntimeError("release unlocked lock")24 25        # Consciously *do not* call super().release(), but instead inline26        # Semaphore.release() here. We've seen issues with logging._lock27        # deadlocking because garbage collection happened to run mid-release28        # and eliminating the extra stack frame should help prevent that.29        # See https://github.com/eventlet/eventlet/issues/74230        self.counter += 131        if self._waiters:32            hubs.get_hub().schedule_call_global(0, self._do_acquire)33        return True34 35    def _at_fork_reinit(self):36        self.counter = 137        self._waiters.clear()38