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kronos-venv/lib/python3.12/site-packages/filelock/_async_read_write.py

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+"""Async wrapper around :class:`ReadWriteLock` for use with ``asyncio``."""
+
+from __future__ import annotations
+
+import asyncio
+import functools
+from concurrent.futures import ThreadPoolExecutor
+from contextlib import asynccontextmanager
+from typing import TYPE_CHECKING
+
+from ._read_write import ReadWriteLock
+
+if TYPE_CHECKING:
+    import os
+    from collections.abc import AsyncGenerator, Callable
+    from concurrent import futures
+    from types import TracebackType
+
+
+class AsyncAcquireReadWriteReturnProxy:
+    """Context-aware object that releases the async read/write lock on exit."""
+
+    def __init__(self, lock: AsyncReadWriteLock) -> None:
+        self.lock = lock
+
+    async def __aenter__(self) -> AsyncReadWriteLock:
+        return self.lock
+
+    async def __aexit__(
+        self,
+        exc_type: type[BaseException] | None,
+        exc_value: BaseException | None,
+        traceback: TracebackType | None,
+    ) -> None:
+        await self.lock.release()
+
+
+class AsyncReadWriteLock:
+    """
+    Async wrapper around :class:`ReadWriteLock` for use in ``asyncio`` applications.
+
+    Because Python's :mod:`sqlite3` module has no async API, all blocking SQLite operations are dispatched to a thread
+    pool via ``loop.run_in_executor()``. Reentrancy, upgrade/downgrade rules, and singleton behavior are delegated
+    to the underlying :class:`ReadWriteLock`.
+
+    :param lock_file: path to the SQLite database file used as the lock
+    :param timeout: maximum wait time in seconds; ``-1`` means block indefinitely
+    :param blocking: if ``False``, raise :class:`~filelock.Timeout` immediately when the lock is unavailable
+    :param is_singleton: if ``True``, reuse existing :class:`ReadWriteLock` instances for the same resolved path
+    :param loop: event loop for ``run_in_executor``; ``None`` uses the running loop
+    :param executor: executor for ``run_in_executor``; ``None`` uses the default executor
+
+    .. versionadded:: 3.21.0
+
+    """
+
+    def __init__(  # noqa: PLR0913
+        self,
+        lock_file: str | os.PathLike[str],
+        timeout: float = -1,
+        *,
+        blocking: bool = True,
+        is_singleton: bool = True,
+        loop: asyncio.AbstractEventLoop | None = None,
+        executor: futures.Executor | None = None,
+    ) -> None:
+        self._lock = ReadWriteLock(lock_file, timeout, blocking=blocking, is_singleton=is_singleton)
+        self._loop = loop
+        self._owns_executor = executor is None
+        self._executor = executor or ThreadPoolExecutor(max_workers=1)
+
+    @property
+    def lock_file(self) -> str:
+        """:returns: the path to the lock file."""
+        return self._lock.lock_file
+
+    @property
+    def timeout(self) -> float:
+        """:returns: the default timeout."""
+        return self._lock.timeout
+
+    @property
+    def blocking(self) -> bool:
+        """:returns: whether blocking is enabled by default."""
+        return self._lock.blocking
+
+    @property
+    def loop(self) -> asyncio.AbstractEventLoop | None:
+        """:returns: the event loop (or ``None`` for the running loop)."""
+        return self._loop
+
+    @property
+    def executor(self) -> futures.Executor | None:
+        """:returns: the executor (or ``None`` for the default)."""
+        return self._executor
+
+    async def _run(self, func: Callable[..., object], *args: object, **kwargs: object) -> object:
+        loop = self._loop or asyncio.get_running_loop()
+        return await loop.run_in_executor(self._executor, functools.partial(func, *args, **kwargs))
+
+    async def acquire_read(self, timeout: float = -1, *, blocking: bool = True) -> AsyncAcquireReadWriteReturnProxy:
+        """
+        Acquire a shared read lock.
+
+        See :meth:`ReadWriteLock.acquire_read` for full semantics.
+
+        :param timeout: maximum wait time in seconds; ``-1`` means block indefinitely
+        :param blocking: if ``False``, raise :class:`~filelock.Timeout` immediately when the lock is unavailable
+
+        :returns: a proxy that can be used as an async context manager to release the lock
+
+        :raises RuntimeError: if a write lock is already held on this instance
+        :raises Timeout: if the lock cannot be acquired within *timeout* seconds
+
+        """
+        await self._run(self._lock.acquire_read, timeout, blocking=blocking)
+        return AsyncAcquireReadWriteReturnProxy(lock=self)
+
+    async def acquire_write(self, timeout: float = -1, *, blocking: bool = True) -> AsyncAcquireReadWriteReturnProxy:
+        """
+        Acquire an exclusive write lock.
+
+        See :meth:`ReadWriteLock.acquire_write` for full semantics.
+
+        :param timeout: maximum wait time in seconds; ``-1`` means block indefinitely
+        :param blocking: if ``False``, raise :class:`~filelock.Timeout` immediately when the lock is unavailable
+
+        :returns: a proxy that can be used as an async context manager to release the lock
+
+        :raises RuntimeError: if a read lock is already held, or a write lock is held by a different thread
+        :raises Timeout: if the lock cannot be acquired within *timeout* seconds
+
+        """
+        await self._run(self._lock.acquire_write, timeout, blocking=blocking)
+        return AsyncAcquireReadWriteReturnProxy(lock=self)
+
+    async def release(self, *, force: bool = False) -> None:
+        """
+        Release one level of the current lock.
+
+        See :meth:`ReadWriteLock.release` for full semantics.
+
+        :param force: if ``True``, release the lock completely regardless of the current lock level
+
+        :raises RuntimeError: if no lock is currently held and *force* is ``False``
+
+        """
+        await self._run(self._lock.release, force=force)
+
+    @asynccontextmanager
+    async def read_lock(self, timeout: float | None = None, *, blocking: bool | None = None) -> AsyncGenerator[None]:
+        """
+        Async context manager that acquires and releases a shared read lock.
+
+        Falls back to instance defaults for *timeout* and *blocking* when ``None``.
+
+        :param timeout: maximum wait time in seconds, or ``None`` to use the instance default
+        :param blocking: if ``False``, raise :class:`~filelock.Timeout` immediately; ``None`` uses the instance default
+
+        """
+        if timeout is None:
+            timeout = self._lock.timeout
+        if blocking is None:
+            blocking = self._lock.blocking
+        await self.acquire_read(timeout, blocking=blocking)
+        try:
+            yield
+        finally:
+            await self.release()
+
+    @asynccontextmanager
+    async def write_lock(self, timeout: float | None = None, *, blocking: bool | None = None) -> AsyncGenerator[None]:
+        """
+        Async context manager that acquires and releases an exclusive write lock.
+
+        Falls back to instance defaults for *timeout* and *blocking* when ``None``.
+
+        :param timeout: maximum wait time in seconds, or ``None`` to use the instance default
+        :param blocking: if ``False``, raise :class:`~filelock.Timeout` immediately; ``None`` uses the instance default
+
+        """
+        if timeout is None:
+            timeout = self._lock.timeout
+        if blocking is None:
+            blocking = self._lock.blocking
+        await self.acquire_write(timeout, blocking=blocking)
+        try:
+            yield
+        finally:
+            await self.release()
+
+    async def close(self) -> None:
+        """
+        Release the lock (if held) and close the underlying SQLite connection.
+
+        After calling this method, the lock instance is no longer usable.
+
+        """
+        await self._run(self._lock.close)
+        if self._owns_executor:
+            self._executor.shutdown(wait=False)
+
+
+__all__ = [
+    "AsyncAcquireReadWriteReturnProxy",
+    "AsyncReadWriteLock",
+]