| import threading |
| import collections |
|
|
|
|
| |
| class FIFOLock(object): |
| def __init__(self): |
| self._lock = threading.Lock() |
| self._inner_lock = threading.Lock() |
| self._pending_threads = collections.deque() |
|
|
| def acquire(self, blocking=True): |
| with self._inner_lock: |
| lock_acquired = self._lock.acquire(False) |
| if lock_acquired: |
| return True |
| elif not blocking: |
| return False |
|
|
| release_event = threading.Event() |
| self._pending_threads.append(release_event) |
|
|
| release_event.wait() |
| return self._lock.acquire() |
|
|
| def release(self): |
| with self._inner_lock: |
| if self._pending_threads: |
| release_event = self._pending_threads.popleft() |
| release_event.set() |
|
|
| self._lock.release() |
|
|
| __enter__ = acquire |
|
|
| def __exit__(self, t, v, tb): |
| self.release() |
|
|
