# 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 import errno 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 self.locked = False def __enter__(self): if has_fcntl: try: fcntl.flock(self.fd, self.mode) self.locked = True except IOError as e: if e.errno != errno.ENOLCK: raise e return self def __exit__(self, *args): if has_fcntl and self.locked: fcntl.flock(self.fd, fcntl.LOCK_UN) # vim: sw=4 ts=4 sts=4 ai et