# This file is part of comma, a generic and flexible library
# Copyright (c) 2011 The University of Sydney
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#
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#    notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
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#    documentation and/or other materials provided with the distribution.
# 3. Neither the name of the University of Sydney nor the
#    names of its contributors may be used to endorse or promote products
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# GRANTED BY THIS LICENSE.  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT
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from __future__ import absolute_import
import signal
import sys
import os

MANAGED_SIGNALS = (signal.SIGINT, signal.SIGTERM, signal.SIGHUP)


class is_shutdown(object):
    def __init__(self):
        self.state = False
        for s in MANAGED_SIGNALS:
            signal.signal(s, self.switch_on)

    def switch_on(self, signum, frame):
        print >> sys.stderr, os.path.basename(sys.argv[0]), "caught signal:", signum
        self.state = True

    def __nonzero__(self):
        return self.state

signal.signal(signal.SIGPIPE, signal.SIG_DFL)
