Quelle _soft.py Sprache: Python

from __future__ import annotations

import os
import sys
from contextlib import suppress
from errno import EACCES, EEXIST
from pathlib import Path

from ._api import BaseFileLock
from ._util import ensure_directory_exists, raise_on_not_writable_file

class SoftFileLock(BaseFileLock):
    """Simply watches the existence of the lock file."""

    def _acquire(self) -> None:
        raise_on_not_writable_file(self.lock_file)
        ensure_directory_exists(self.lock_file)
        # first check for exists and read-only mode as the open will mask this case as EEXIST
        flags = (
            os.O_WRONLY  # open for writing only
            | os.O_CREAT
            | os.O_EXCL  # together with above raise EEXIST if the file specified by filename exists
            | os.O_TRUNC  # truncate the file to zero byte
        )
        try:
            file_handler = os.open(self.lock_file, flags, self._context.mode)
        except OSError as exception:  # re-raise unless expected exception
            if not (
                exception.errno == EEXIST  # lock already exist
                or (exception.errno == EACCES and sys.platform == "win32")  # has no access to this lock
            ):  # pragma: win32 no cover
                raise
        else:
            self._context.lock_file_fd = file_handler

    def _release(self) -> None:
        assert self._context.lock_file_fd is not None  # noqa: S101
        os.close(self._context.lock_file_fd)  # the lock file is definitely not None
        self._context.lock_file_fd = None
        with suppress(OSError):  # the file is already deleted and that's what we want
            Path(self.lock_file).unlink()

__all__ = [
    "SoftFileLock",
]

quality100%

¤ Dauer der Verarbeitung: 0.22 Sekunden (vorverarbeitet) ¤

Wurzel

Suchen

Beweissystem der NASA

Beweissystem Isabelle

NIST Cobol Testsuite

Cephes Mathematical Library

Wiener Entwicklungsmethode

Haftungshinweis

Die Informationen auf dieser Webseite wurden nach bestem Wissen sorgfältig zusammengestellt. Es wird jedoch weder Vollständigkeit, noch Richtigkeit, noch Qualität der bereit gestellten Informationen zugesichert.

Bemerkung:

Die farbliche Syntaxdarstellung ist noch experimentell.