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			337 lines
		
	
	
	
		
			9.6 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
			
		
		
	
	
			337 lines
		
	
	
	
		
			9.6 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
#
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# Module providing various facilities to other parts of the package
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#
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# multiprocessing/util.py
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#
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# Copyright (c) 2006-2008, R Oudkerk
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# All rights reserved.
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#
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# Redistribution and use in source and binary forms, with or without
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# modification, are permitted provided that the following conditions
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# are met:
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#
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# 1. Redistributions of source code must retain the above copyright
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#    notice, this list of conditions and the following disclaimer.
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# 2. Redistributions in binary form must reproduce the above copyright
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#    notice, this list of conditions and the following disclaimer in the
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#    documentation and/or other materials provided with the distribution.
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# 3. Neither the name of author nor the names of any contributors may be
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#    used to endorse or promote products derived from this software
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#    without specific prior written permission.
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#
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# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS "AS IS" AND
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# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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# ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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# SUCH DAMAGE.
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#
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import functools
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import itertools
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import weakref
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import atexit
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import threading        # we want threading to install it's
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                        # cleanup function before multiprocessing does
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from multiprocessing.process import current_process, active_children
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__all__ = [
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    'sub_debug', 'debug', 'info', 'sub_warning', 'get_logger',
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    'log_to_stderr', 'get_temp_dir', 'register_after_fork',
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    'is_exiting', 'Finalize', 'ForkAwareThreadLock', 'ForkAwareLocal',
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    'SUBDEBUG', 'SUBWARNING',
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    ]
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#
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# Logging
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#
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NOTSET = 0
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SUBDEBUG = 5
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DEBUG = 10
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INFO = 20
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SUBWARNING = 25
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LOGGER_NAME = 'multiprocessing'
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DEFAULT_LOGGING_FORMAT = '[%(levelname)s/%(processName)s] %(message)s'
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_logger = None
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_log_to_stderr = False
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def sub_debug(msg, *args):
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    if _logger:
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        _logger.log(SUBDEBUG, msg, *args)
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def debug(msg, *args):
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    if _logger:
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        _logger.log(DEBUG, msg, *args)
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def info(msg, *args):
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    if _logger:
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        _logger.log(INFO, msg, *args)
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def sub_warning(msg, *args):
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    if _logger:
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        _logger.log(SUBWARNING, msg, *args)
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def get_logger():
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    '''
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    Returns logger used by multiprocessing
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    '''
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    global _logger
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    import logging
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    logging._acquireLock()
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    try:
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        if not _logger:
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            _logger = logging.getLogger(LOGGER_NAME)
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            _logger.propagate = 0
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            logging.addLevelName(SUBDEBUG, 'SUBDEBUG')
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            logging.addLevelName(SUBWARNING, 'SUBWARNING')
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            # XXX multiprocessing should cleanup before logging
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            if hasattr(atexit, 'unregister'):
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                atexit.unregister(_exit_function)
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                atexit.register(_exit_function)
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            else:
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                atexit._exithandlers.remove((_exit_function, (), {}))
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                atexit._exithandlers.append((_exit_function, (), {}))
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    finally:
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        logging._releaseLock()
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    return _logger
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def log_to_stderr(level=None):
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    '''
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    Turn on logging and add a handler which prints to stderr
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    '''
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    global _log_to_stderr
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    import logging
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    logger = get_logger()
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    formatter = logging.Formatter(DEFAULT_LOGGING_FORMAT)
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    handler = logging.StreamHandler()
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    handler.setFormatter(formatter)
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    logger.addHandler(handler)
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    if level:
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        logger.setLevel(level)
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    _log_to_stderr = True
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    return _logger
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#
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# Function returning a temp directory which will be removed on exit
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#
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def get_temp_dir():
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    # get name of a temp directory which will be automatically cleaned up
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    if current_process()._tempdir is None:
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        import shutil, tempfile
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        tempdir = tempfile.mkdtemp(prefix='pymp-')
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        info('created temp directory %s', tempdir)
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        Finalize(None, shutil.rmtree, args=[tempdir], exitpriority=-100)
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        current_process()._tempdir = tempdir
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    return current_process()._tempdir
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#
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# Support for reinitialization of objects when bootstrapping a child process
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#
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_afterfork_registry = weakref.WeakValueDictionary()
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_afterfork_counter = itertools.count()
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def _run_after_forkers():
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    items = list(_afterfork_registry.items())
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    items.sort()
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    for (index, ident, func), obj in items:
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        try:
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            func(obj)
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        except Exception as e:
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            info('after forker raised exception %s', e)
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def register_after_fork(obj, func):
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    _afterfork_registry[(next(_afterfork_counter), id(obj), func)] = obj
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#
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# Finalization using weakrefs
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#
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_finalizer_registry = {}
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_finalizer_counter = itertools.count()
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class Finalize(object):
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    '''
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    Class which supports object finalization using weakrefs
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    '''
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    def __init__(self, obj, callback, args=(), kwargs=None, exitpriority=None):
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        assert exitpriority is None or type(exitpriority) is int
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        if obj is not None:
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            self._weakref = weakref.ref(obj, self)
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        else:
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            assert exitpriority is not None
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        self._callback = callback
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        self._args = args
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        self._kwargs = kwargs or {}
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        self._key = (exitpriority, next(_finalizer_counter))
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        _finalizer_registry[self._key] = self
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    def __call__(self, wr=None,
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                 # Need to bind these locally because the globals can have
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                 # been cleared at shutdown
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                 _finalizer_registry=_finalizer_registry,
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                 sub_debug=sub_debug):
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        '''
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        Run the callback unless it has already been called or cancelled
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        '''
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        try:
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            del _finalizer_registry[self._key]
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        except KeyError:
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            sub_debug('finalizer no longer registered')
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        else:
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            sub_debug('finalizer calling %s with args %s and kwargs %s',
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                     self._callback, self._args, self._kwargs)
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            res = self._callback(*self._args, **self._kwargs)
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            self._weakref = self._callback = self._args = \
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                            self._kwargs = self._key = None
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            return res
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    def cancel(self):
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        '''
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        Cancel finalization of the object
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        '''
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        try:
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            del _finalizer_registry[self._key]
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        except KeyError:
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            pass
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        else:
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            self._weakref = self._callback = self._args = \
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                            self._kwargs = self._key = None
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    def still_active(self):
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        '''
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        Return whether this finalizer is still waiting to invoke callback
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        '''
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        return self._key in _finalizer_registry
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    def __repr__(self):
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        try:
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            obj = self._weakref()
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        except (AttributeError, TypeError):
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            obj = None
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        if obj is None:
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            return '<Finalize object, dead>'
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        x = '<Finalize object, callback=%s' % \
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            getattr(self._callback, '__name__', self._callback)
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        if self._args:
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            x += ', args=' + str(self._args)
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        if self._kwargs:
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            x += ', kwargs=' + str(self._kwargs)
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        if self._key[0] is not None:
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            x += ', exitprority=' + str(self._key[0])
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        return x + '>'
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def _run_finalizers(minpriority=None):
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    '''
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    Run all finalizers whose exit priority is not None and at least minpriority
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    Finalizers with highest priority are called first; finalizers with
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    the same priority will be called in reverse order of creation.
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    '''
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    if minpriority is None:
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        f = lambda p : p[0][0] is not None
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    else:
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        f = lambda p : p[0][0] is not None and p[0][0] >= minpriority
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    items = [x for x in list(_finalizer_registry.items()) if f(x)]
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    items.sort(reverse=True)
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    for key, finalizer in items:
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        sub_debug('calling %s', finalizer)
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        try:
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            finalizer()
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        except Exception:
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            import traceback
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            traceback.print_exc()
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    if minpriority is None:
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        _finalizer_registry.clear()
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#
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# Clean up on exit
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#
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def is_exiting():
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    '''
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    Returns true if the process is shutting down
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    '''
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    return _exiting or _exiting is None
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_exiting = False
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def _exit_function():
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    global _exiting
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    info('process shutting down')
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    debug('running all "atexit" finalizers with priority >= 0')
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    _run_finalizers(0)
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    for p in active_children():
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        if p._daemonic:
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            info('calling terminate() for daemon %s', p.name)
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            p._popen.terminate()
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    for p in active_children():
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        info('calling join() for process %s', p.name)
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        p.join()
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    debug('running the remaining "atexit" finalizers')
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    _run_finalizers()
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atexit.register(_exit_function)
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#
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# Some fork aware types
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#
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class ForkAwareThreadLock(object):
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    def __init__(self):
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        self._lock = threading.Lock()
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        self.acquire = self._lock.acquire
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        self.release = self._lock.release
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        register_after_fork(self, ForkAwareThreadLock.__init__)
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class ForkAwareLocal(threading.local):
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    def __init__(self):
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        register_after_fork(self, lambda obj : obj.__dict__.clear())
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    def __reduce__(self):
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        return type(self), ()
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#
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# Automatic retry after EINTR
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#
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def _eintr_retry(func):
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    @functools.wraps(func)
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    def wrapped(*args, **kwargs):
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        while True:
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            try:
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                return func(*args, **kwargs)
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            except InterruptedError:
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                continue
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    return wrapped
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