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filelock.py
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115 lines (89 loc) · 2.86 KB
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# encoding: utf-8
# The MIT License
#
# Copyright (c) 2015-2016 Sebastian Ramacher
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
from __future__importabsolute_import
try:
importfcntl
importerrno
has_fcntl=True
exceptImportError:
has_fcntl=False
try:
importmsvcrt
has_msvcrt=True
exceptImportError:
has_msvcrt=False
classBaseLock(object):
"""Base class for file locking
"""
def__init__(self,fd):
self.fd=fd
self.locked=False
defacquire(self):
pass
defrelease(self):
pass
def__enter__(self):
self.acquire()
returnself
def__exit__(self,*args):
ifself.locked:
self.release()
def__del__(self):
ifself.locked:
self.release()
classUnixFileLock(BaseLock):
"""Simple file locking for Unix using fcntl
"""
def__init__(self,fd,mode=None):
super(UnixFileLock,self).__init__(fd)
ifmodeisNone:
mode=fcntl.LOCK_EX
self.mode=mode
defacquire(self):
try:
fcntl.flock(self.fd,self.mode)
self.locked=True
exceptIOErrorase:
ife.errno!=errno.ENOLCK:
raisee
defrelease(self):
fcntl.flock(self.fd,fcntl.LOCK_UN)
self.locked=False
classWindowsFileLock(BaseLock):
"""Simple file locking for Windows using msvcrt
"""
def__init__(self,fd,mode=None):
super(WindowsFileLock,self).__init__(fd)
defacquire(self):
msvcrt.locking(self.fd,msvcrt.LK_NBLCK,1)
self.locked=True
defrelease(self):
msvcrt.locking(self.fd,msvcrt.LK_UNLCK,1)
self.locked=False
ifhas_fcntl:
FileLock=UnixFileLock
elifhas_msvcrt:
FileLock=WindowsFileLock
else:
FileLock=BaseLock
# vim: sw=4 ts=4 sts=4 ai et