#!/usr/bin/python
# Copyright (c) 2015 Hewlett-Packard Development Company, L.P.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
# implied.
# See the License for the specific language governing permissions and
# limitations under the License.

import fcntl


class Lock(object):
    def __init__(self, filename):
        self.filename = filename

    def __enter__(self):
        fh = open(self.filename, 'w')
        fcntl.flock(fh, fcntl.LOCK_EX)

    def __exit__(self, exc_type, exc_value, traceback):
        fh = open(self.filename, 'w')
        fcntl.flock(fh, fcntl.LOCK_UN)
