143 lines
4.3 KiB
Python
143 lines
4.3 KiB
Python
# Copyright 2022-present MongoDB, Inc.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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from __future__ import annotations
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import asyncio
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import os
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import threading
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import time
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import weakref
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from typing import Any, Callable, Optional
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_HAS_REGISTER_AT_FORK = hasattr(os, "register_at_fork")
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# References to instances of _create_lock
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_forkable_locks: weakref.WeakSet[threading.Lock] = weakref.WeakSet()
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def _create_lock() -> threading.Lock:
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"""Represents a lock that is tracked upon instantiation using a WeakSet and
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reset by pymongo upon forking.
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"""
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lock = threading.Lock()
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if _HAS_REGISTER_AT_FORK:
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_forkable_locks.add(lock)
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return lock
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def _release_locks() -> None:
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# Completed the fork, reset all the locks in the child.
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for lock in _forkable_locks:
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if lock.locked():
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lock.release()
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class _ALock:
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def __init__(self, lock: threading.Lock) -> None:
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self._lock = lock
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def acquire(self, blocking: bool = True, timeout: float = -1) -> bool:
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return self._lock.acquire(blocking=blocking, timeout=timeout)
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async def a_acquire(self, blocking: bool = True, timeout: float = -1) -> bool:
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if timeout > 0:
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tstart = time.monotonic()
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while True:
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acquired = self._lock.acquire(blocking=False)
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if acquired:
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return True
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if timeout > 0 and (time.monotonic() - tstart) > timeout:
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return False
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if not blocking:
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return False
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await asyncio.sleep(0)
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def release(self) -> None:
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self._lock.release()
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async def __aenter__(self) -> _ALock:
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await self.a_acquire()
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return self
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def __enter__(self) -> _ALock:
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self._lock.acquire()
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return self
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def __exit__(self, exc_type: Any, exc: Any, tb: Any) -> None:
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self.release()
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async def __aexit__(self, exc_type: Any, exc: Any, tb: Any) -> None:
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self.release()
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class _ACondition:
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def __init__(self, condition: threading.Condition) -> None:
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self._condition = condition
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async def acquire(self, blocking: bool = True, timeout: float = -1) -> bool:
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if timeout > 0:
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tstart = time.monotonic()
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while True:
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acquired = self._condition.acquire(blocking=False)
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if acquired:
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return True
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if timeout > 0 and (time.monotonic() - tstart) > timeout:
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return False
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if not blocking:
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return False
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await asyncio.sleep(0)
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async def wait(self, timeout: Optional[float] = None) -> bool:
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if timeout is not None:
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tstart = time.monotonic()
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while True:
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notified = self._condition.wait(0.001)
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if notified:
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return True
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if timeout is not None and (time.monotonic() - tstart) > timeout:
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return False
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async def wait_for(self, predicate: Callable, timeout: Optional[float] = None) -> bool:
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if timeout is not None:
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tstart = time.monotonic()
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while True:
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notified = self._condition.wait_for(predicate, 0.001)
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if notified:
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return True
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if timeout is not None and (time.monotonic() - tstart) > timeout:
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return False
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def notify(self, n: int = 1) -> None:
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self._condition.notify(n)
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def notify_all(self) -> None:
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self._condition.notify_all()
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def release(self) -> None:
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self._condition.release()
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async def __aenter__(self) -> _ACondition:
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await self.acquire()
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return self
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def __enter__(self) -> _ACondition:
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self._condition.acquire()
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return self
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async def __aexit__(self, exc_type: Any, exc: Any, tb: Any) -> None:
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self.release()
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def __exit__(self, exc_type: Any, exc: Any, tb: Any) -> None:
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self.release()
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