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# -*- coding: utf-8 -*-
#
# AWL simulator - 'with'-statement based single threaded action blocker
#
# Copyright 2014 Michael Buesch <m@bues.ch>
#
# 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.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
#
from __future__ import division, absolute_import, print_function, unicode_literals
from awlsim.common.compat import *
class Blocker(object):
"""'with'-statement based single threaded blocker.
This is _not_ a multi-thread lock."""
def __init__(self, initialCount = 0):
self.__count = initialCount
assert(self.__count >= 0)
def __enter__(self):
"""Enter the blocking context."""
assert(self.__count >= 0)
self.__count += 1
def __exit__(self, exc_type, exc_value, traceback):
"""Exit the blocking context."""
self.__count -= 1
assert(self.__count >= 0)
def __bool__(self):
"""Returns 'True', if the action is blocked."""
return self.__count > 0
__nonzero__ = __bool__ # Python 2 compat
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