38 lines
1020 B
Python
38 lines
1020 B
Python
import threading
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import collections
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# reference: https://gist.github.com/vitaliyp/6d54dd76ca2c3cdfc1149d33007dc34a
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class FIFOLock(object):
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def __init__(self):
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self._lock = threading.Lock()
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self._inner_lock = threading.Lock()
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self._pending_threads = collections.deque()
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def acquire(self, blocking=True):
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with self._inner_lock:
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lock_acquired = self._lock.acquire(False)
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if lock_acquired:
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return True
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elif not blocking:
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return False
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release_event = threading.Event()
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self._pending_threads.append(release_event)
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release_event.wait()
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return self._lock.acquire()
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def release(self):
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with self._inner_lock:
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if self._pending_threads:
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release_event = self._pending_threads.popleft()
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release_event.set()
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self._lock.release()
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__enter__ = acquire
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def __exit__(self, t, v, tb):
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self.release()
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