cpython/Lib/multiprocessing/dummy/__init__.py

#
# Support for the API of the multiprocessing package using threads
#
# multiprocessing/dummy/__init__.py
#
# Copyright (c) 2006-2008, R Oudkerk
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
#
# 1. Redistributions of source code must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
#    notice, this list of conditions and the following disclaimer in the
#    documentation and/or other materials provided with the distribution.
# 3. Neither the name of author nor the names of any contributors may be
#    used to endorse or promote products derived from this software
#    without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS "AS IS" AND
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
# SUCH DAMAGE.
#

__all__ = [
    'Process', 'current_process', 'active_children', 'freeze_support',
    'Lock', 'RLock', 'Semaphore', 'BoundedSemaphore', 'Condition',
    'Event', 'Queue', 'Manager', 'Pipe', 'Pool', 'JoinableQueue'
    ]

#
# Imports
#

import threading
import sys
import weakref
import array
import itertools

from multiprocessing import TimeoutError, cpu_count
from multiprocessing.dummy.connection import Pipe
from threading import Lock, RLock, Semaphore, BoundedSemaphore
from threading import Event
from queue import Queue

#
#
#

class DummyProcess(threading.Thread):

    def __init__(self, group=None, target=None, name=None, args=(), kwargs={}):
        threading.Thread.__init__(self, group, target, name, args, kwargs)
        self._pid = None
        self._children = weakref.WeakKeyDictionary()
        self._start_called = False
        self._parent = current_process()

    def start(self):
        assert self._parent is current_process()
        self._start_called = True
        if hasattr(self._parent, '_children'):
            self._parent._children[self] = None
        threading.Thread.start(self)

    @property
    def exitcode(self):
        if self._start_called and not self.is_alive():
            return 0
        else:
            return None

#
#
#

class Condition(threading._Condition):
    # XXX
    if sys.version_info < (3, 0):
        notify_all = threading._Condition.notify_all.__func__
    else:
        notify_all = threading._Condition.notify_all

#
#
#

Process = DummyProcess
current_process = threading.current_thread
current_process()._children = weakref.WeakKeyDictionary()

def active_children():
    children = current_process()._children
    for p in list(children):
        if not p.is_alive():
            children.pop(p, None)
    return list(children)

def freeze_support():
    pass

#
#
#

class Namespace(object):
    def __init__(self, **kwds):
        self.__dict__.update(kwds)
    def __repr__(self):
        items = list(self.__dict__.items())
        temp = []
        for name, value in items:
            if not name.startswith('_'):
                temp.append('%s=%r' % (name, value))
        temp.sort()
        return 'Namespace(%s)' % str.join(', ', temp)

dict = dict
list = list

def Array(typecode, sequence, lock=True):
    return array.array(typecode, sequence)

class Value(object):
    def __init__(self, typecode, value, lock=True):
        self._typecode = typecode
        self._value = value
    def _get(self):
        return self._value
    def _set(self, value):
        self._value = value
    value = property(_get, _set)
    def __repr__(self):
        return '<%r(%r, %r)>'%(type(self).__name__,self._typecode,self._value)

def Manager():
    return sys.modules[__name__]

def shutdown():
    pass

def Pool(processes=None, initializer=None, initargs=()):
    from multiprocessing.pool import ThreadPool
    return ThreadPool(processes, initializer, initargs)

JoinableQueue = Queue