linkchecker/linkcheck/lock.py
2005-10-13 22:26:12 +00:00

57 lines
1.7 KiB
Python

# -*- coding: iso-8859-1 -*-
# Copyright (C) 2005 Bastian Kleineidam
#
# 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 2 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, write to the Free Software
# Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
"""
Locking utility class.
"""
try:
import threading
except ImportError:
import dummy_threading as threading
import linkcheck
import linkcheck.log
lock_klass = threading.RLock().__class__
class AssertLock (lock_klass):
"""
Lock class asserting that only available locks are acquired,
and that no lock is released twice.
"""
def acquire (self, blocking=True):
"""
Acquire lock.
"""
assert not self.is_locked(), "deadlock"
linkcheck.log.debug(linkcheck.LOG_THREAD, "Acquire %s", self)
super(AssertLock, self).acquire(blocking=blocking)
def release (self):
"""
Release lock.
"""
assert self.is_locked(), "double release"
linkcheck.log.debug(linkcheck.LOG_THREAD, "Release %s", self)
super(AssertLock, self).release()
def is_locked (self):
"""
See if this lock is owned.
"""
return self._is_owned()