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| from __future__ import annotations | |
| import os | |
| import sys | |
| from contextlib import suppress | |
| from errno import EACCES | |
| from pathlib import Path | |
| from typing import cast | |
| from ._api import BaseFileLock | |
| from ._util import ensure_directory_exists, raise_on_not_writable_file | |
| if sys.platform == "win32": # pragma: win32 cover | |
| import msvcrt | |
| class WindowsFileLock(BaseFileLock): | |
| """Uses the :func:`msvcrt.locking` function to hard lock the lock file on Windows systems.""" | |
| def _acquire(self) -> None: | |
| raise_on_not_writable_file(self.lock_file) | |
| ensure_directory_exists(self.lock_file) | |
| flags = ( | |
| os.O_RDWR # open for read and write | |
| | os.O_CREAT # create file if not exists | |
| | os.O_TRUNC # truncate file if not empty | |
| ) | |
| try: | |
| fd = os.open(self.lock_file, flags, self._context.mode) | |
| except OSError as exception: | |
| if exception.errno != EACCES: # has no access to this lock | |
| raise | |
| else: | |
| try: | |
| msvcrt.locking(fd, msvcrt.LK_NBLCK, 1) | |
| except OSError as exception: | |
| os.close(fd) # close file first | |
| if exception.errno != EACCES: # file is already locked | |
| raise | |
| else: | |
| self._context.lock_file_fd = fd | |
| def _release(self) -> None: | |
| fd = cast(int, self._context.lock_file_fd) | |
| self._context.lock_file_fd = None | |
| msvcrt.locking(fd, msvcrt.LK_UNLCK, 1) | |
| os.close(fd) | |
| with suppress(OSError): # Probably another instance of the application hat acquired the file lock. | |
| Path(self.lock_file).unlink() | |
| else: # pragma: win32 no cover | |
| class WindowsFileLock(BaseFileLock): | |
| """Uses the :func:`msvcrt.locking` function to hard lock the lock file on Windows systems.""" | |
| def _acquire(self) -> None: | |
| raise NotImplementedError | |
| def _release(self) -> None: | |
| raise NotImplementedError | |
| __all__ = [ | |
| "WindowsFileLock", | |
| ] | |