updates

Backend/venv/lib/python3.12/site-packages/filelock/_unix.py

@@ -0,0 +1,70 @@
+from __future__ import annotations
+
+import os
+import sys
+from contextlib import suppress
+from errno import ENOSYS
+from pathlib import Path
+from typing import cast
+
+from ._api import BaseFileLock
+from ._util import ensure_directory_exists
+
+#: a flag to indicate if the fcntl API is available
+has_fcntl = False
+if sys.platform == "win32":  # pragma: win32 cover
+
+    class UnixFileLock(BaseFileLock):
+        """Uses the :func:`fcntl.flock` to hard lock the lock file on unix systems."""
+
+        def _acquire(self) -> None:
+            raise NotImplementedError
+
+        def _release(self) -> None:
+            raise NotImplementedError
+
+else:  # pragma: win32 no cover
+    try:
+        import fcntl
+
+        _ = (fcntl.flock, fcntl.LOCK_EX, fcntl.LOCK_NB, fcntl.LOCK_UN)
+    except (ImportError, AttributeError):
+        pass
+    else:
+        has_fcntl = True
+
+    class UnixFileLock(BaseFileLock):
+        """Uses the :func:`fcntl.flock` to hard lock the lock file on unix systems."""
+
+        def _acquire(self) -> None:
+            ensure_directory_exists(self.lock_file)
+            open_flags = os.O_RDWR | os.O_TRUNC
+            if not Path(self.lock_file).exists():
+                open_flags |= os.O_CREAT
+            fd = os.open(self.lock_file, open_flags, self._context.mode)
+            with suppress(PermissionError):  # This locked is not owned by this UID
+                os.fchmod(fd, self._context.mode)
+            try:
+                fcntl.flock(fd, fcntl.LOCK_EX | fcntl.LOCK_NB)
+            except OSError as exception:
+                os.close(fd)
+                if exception.errno == ENOSYS:  # NotImplemented error
+                    msg = "FileSystem does not appear to support flock; use SoftFileLock instead"
+                    raise NotImplementedError(msg) from exception
+            else:
+                self._context.lock_file_fd = fd
+
+        def _release(self) -> None:
+            # Do not remove the lockfile:
+            #   https://github.com/tox-dev/py-filelock/issues/31
+            #   https://stackoverflow.com/questions/17708885/flock-removing-locked-file-without-race-condition
+            fd = cast("int", self._context.lock_file_fd)
+            self._context.lock_file_fd = None
+            fcntl.flock(fd, fcntl.LOCK_UN)
+            os.close(fd)
+
+
+__all__ = [
+    "UnixFileLock",
+    "has_fcntl",
+]