codekingpro/portable-devtools

1from __future__ import annotations2 3import os4import sys5from contextlib import suppress6from errno import EACCES7from pathlib import Path8from typing import cast9 10from ._api import BaseFileLock11from ._util import ensure_directory_exists, raise_on_not_writable_file12 13if sys.platform == "win32":  # pragma: win32 cover14    import msvcrt15 16    class WindowsFileLock(BaseFileLock):17        """Uses the :func:`msvcrt.locking` function to hard lock the lock file on Windows systems."""18 19        def _acquire(self) -> None:20            raise_on_not_writable_file(self.lock_file)21            ensure_directory_exists(self.lock_file)22            flags = (23                os.O_RDWR  # open for read and write24                | os.O_CREAT  # create file if not exists25                | os.O_TRUNC  # truncate file if not empty26            )27            try:28                fd = os.open(self.lock_file, flags, self._context.mode)29            except OSError as exception:30                if exception.errno != EACCES:  # has no access to this lock31                    raise32            else:33                try:34                    msvcrt.locking(fd, msvcrt.LK_NBLCK, 1)35                except OSError as exception:36                    os.close(fd)  # close file first37                    if exception.errno != EACCES:  # file is already locked38                        raise39                else:40                    self._context.lock_file_fd = fd41 42        def _release(self) -> None:43            fd = cast(int, self._context.lock_file_fd)44            self._context.lock_file_fd = None45            msvcrt.locking(fd, msvcrt.LK_UNLCK, 1)46            os.close(fd)47 48            with suppress(OSError):  # Probably another instance of the application hat acquired the file lock.49                Path(self.lock_file).unlink()50 51else:  # pragma: win32 no cover52 53    class WindowsFileLock(BaseFileLock):54        """Uses the :func:`msvcrt.locking` function to hard lock the lock file on Windows systems."""55 56        def _acquire(self) -> None:57            raise NotImplementedError58 59        def _release(self) -> None:60            raise NotImplementedError61 62 63__all__ = [64    "WindowsFileLock",65]66