# encoding: utf-8

# The MIT License

#

# Copyright (c) 2015 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.

try:

import fcntl

has_fcntl = True

except ImportError:

has_fcntl = False

class FileLock(object):

"""Simple file locking

On platforms without fcntl, all operations in this class are no-ops.

"""

def __init__(self, fd, mode=None):

if has_fcntl and mode is None:

mode = fcntl.LOCK_EX

self.fd = fd

self.mode = mode

def __enter__(self):

if has_fcntl:

fcntl.flock(self.fd, self.mode)

return self

def __exit__(self, *args):

if has_fcntl:

fcntl.flock(self.fd, fcntl.LOCK_UN)

# vim: sw=4 ts=4 sts=4 ai et