/usr/lib/python3/dist-packages/sima/utils/filelock.py is in mpd-sima 0.14.1-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 | # -*- coding: utf-8 -*-
# Copyright (c) 2009 Evan Fosmark
# Copyright (c) 2014 Jack Kaliko <kaliko@azylum.org>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
#
#
# https://github.com/dmfrey/FileLock
"""
Plain file lock to une in context:
>>> with FileLock('/path/to/file/to/write'):
>>> # a lock file is maintain within the scope of this context:
>>> # /path/to/file/to/write.lock
>>> ... # process file writing
"""
import errno
import os
import time
class FileLockException(Exception):
"""FileLock Exception"""
pass
class FileLock:
""" A plain file lock whit context-manager"""
def __init__(self, file_name, timeout=10, delay=.05):
"""
Setup file lock.
Setup timeout and the delay.
"""
self.filedsc = None
self.is_locked = False
dirname = os.path.dirname(file_name)
self.lockfile = os.path.join(dirname, '{0}.lock'.format(file_name))
self.file_name = file_name
self.timeout = timeout
self.delay = delay
def acquire(self):
"""Acquire the lock, if possible.
"""
start_time = time.time()
while True:
try:
self.filedsc = os.open(self.lockfile,
os.O_CREAT|os.O_EXCL|os.O_RDWR)
break
except OSError as err:
if err.errno != errno.EEXIST:
raise
if (time.time() - start_time) >= self.timeout:
raise FileLockException('Timeout occured.')
time.sleep(self.delay)
self.is_locked = True
def release(self):
"""Release the lock.
"""
if self.is_locked:
os.close(self.filedsc)
os.unlink(self.lockfile)
self.is_locked = False
def __enter__(self):
"""start of the with statement.
"""
if not self.is_locked:
self.acquire()
return self
def __exit__(self, type, value, traceback):
"""end of the with statement
"""
if self.is_locked:
self.release()
def __del__(self):
"""Cleanup
"""
self.release()
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