Merged revisions 64104,64117 via svnmerge from

svn+ssh://pythondev@svn.python.org/python/trunk

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  r64104 | benjamin.peterson | 2008-06-10 21:40:25 -0500 (Tue, 10 Jun 2008) | 2 lines

  add the multiprocessing package to fulfill PEP 371
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  r64117 | benjamin.peterson | 2008-06-11 07:26:31 -0500 (Wed, 11 Jun 2008) | 2 lines

  fix import of multiprocessing by juggling imports
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Lib/multiprocessing/__init__.py

@@ -0,0 +1,270 @@
+#
+# Package analogous to 'threading.py' but using processes
+#
+# multiprocessing/__init__.py
+#
+# This package is intended to duplicate the functionality (and much of
+# the API) of threading.py but uses processes instead of threads.  A
+# subpackage 'multiprocessing.dummy' has the same API but is a simple
+# wrapper for 'threading'.
+#
+# Try calling `multiprocessing.doc.main()` to read the html
+# documentation in in a webbrowser.
+#
+#
+# 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
+#
+
+__version__ = '0.70a1'
+
+__all__ = [
+    'Process', 'current_process', 'active_children', 'freeze_support',
+    'Manager', 'Pipe', 'cpu_count', 'log_to_stderr', 'get_logger',
+    'allow_connection_pickling', 'BufferTooShort', 'TimeoutError',
+    'Lock', 'RLock', 'Semaphore', 'BoundedSemaphore', 'Condition',
+    'Event', 'Queue', 'JoinableQueue', 'Pool', 'Value', 'Array',
+    'RawValue', 'RawArray'
+    ]
+
+__author__ = 'R. Oudkerk (r.m.oudkerk@gmail.com)'
+
+#
+# Imports
+#
+
+import os
+import sys
+
+from multiprocessing.process import Process, current_process, active_children
+
+#
+# Exceptions
+#
+
+class ProcessError(Exception):
+    pass
+
+class BufferTooShort(ProcessError):
+    pass
+
+class TimeoutError(ProcessError):
+    pass
+
+class AuthenticationError(ProcessError):
+    pass
+
+import _multiprocessing
+
+#
+# Definitions not depending on native semaphores
+#
+
+def Manager():
+    '''
+    Returns a manager associated with a running server process
+
+    The managers methods such as `Lock()`, `Condition()` and `Queue()`
+    can be used to create shared objects.
+    '''
+    from multiprocessing.managers import SyncManager
+    m = SyncManager()
+    m.start()
+    return m
+
+def Pipe(duplex=True):
+    '''
+    Returns two connection object connected by a pipe
+    '''
+    from multiprocessing.connection import Pipe
+    return Pipe(duplex)
+
+def cpu_count():
+    '''
+    Returns the number of CPUs in the system
+    '''
+    if sys.platform == 'win32':
+        try:
+            num = int(os.environ['NUMBER_OF_PROCESSORS'])
+        except (ValueError, KeyError):
+            num = 0
+    elif sys.platform == 'darwin':
+        try:
+            num = int(os.popen('sysctl -n hw.ncpu').read())
+        except ValueError:
+            num = 0
+    else:
+        try:
+            num = os.sysconf('SC_NPROCESSORS_ONLN')
+        except (ValueError, OSError, AttributeError):
+            num = 0
+
+    if num >= 1:
+        return num
+    else:
+        raise NotImplementedError('cannot determine number of cpus')
+
+def freeze_support():
+    '''
+    Check whether this is a fake forked process in a frozen executable.
+    If so then run code specified by commandline and exit.
+    '''
+    if sys.platform == 'win32' and getattr(sys, 'frozen', False):
+        from multiprocessing.forking import freeze_support
+        freeze_support()
+
+def get_logger():
+    '''
+    Return package logger -- if it does not already exist then it is created
+    '''
+    from multiprocessing.util import get_logger
+    return get_logger()
+
+def log_to_stderr(level=None):
+    '''
+    Turn on logging and add a handler which prints to stderr
+    '''
+    from multiprocessing.util import log_to_stderr
+    return log_to_stderr(level)
+
+def allow_connection_pickling():
+    '''
+    Install support for sending connections and sockets between processes
+    '''
+    from multiprocessing import reduction
+
+#
+# Definitions depending on native semaphores
+#
+
+def Lock():
+    '''
+    Returns a non-recursive lock object
+    '''
+    from multiprocessing.synchronize import Lock
+    return Lock()
+
+def RLock():
+    '''
+    Returns a recursive lock object
+    '''
+    from multiprocessing.synchronize import RLock
+    return RLock()
+
+def Condition(lock=None):
+    '''
+    Returns a condition object
+    '''
+    from multiprocessing.synchronize import Condition
+    return Condition(lock)
+
+def Semaphore(value=1):
+    '''
+    Returns a semaphore object
+    '''
+    from multiprocessing.synchronize import Semaphore
+    return Semaphore(value)
+
+def BoundedSemaphore(value=1):
+    '''
+    Returns a bounded semaphore object
+    '''
+    from multiprocessing.synchronize import BoundedSemaphore
+    return BoundedSemaphore(value)
+
+def Event():
+    '''
+    Returns an event object
+    '''
+    from multiprocessing.synchronize import Event
+    return Event()
+
+def Queue(maxsize=0):
+    '''
+    Returns a queue object
+    '''
+    from multiprocessing.queues import Queue
+    return Queue(maxsize)
+
+def JoinableQueue(maxsize=0):
+    '''
+    Returns a queue object
+    '''
+    from multiprocessing.queues import JoinableQueue
+    return JoinableQueue(maxsize)
+
+def Pool(processes=None, initializer=None, initargs=()):
+    '''
+    Returns a process pool object
+    '''
+    from multiprocessing.pool import Pool
+    return Pool(processes, initializer, initargs)
+
+def RawValue(typecode_or_type, *args):
+    '''
+    Returns a shared object
+    '''
+    from multiprocessing.sharedctypes import RawValue
+    return RawValue(typecode_or_type, *args)
+
+def RawArray(typecode_or_type, size_or_initializer):
+    '''
+    Returns a shared array
+    '''
+    from multiprocessing.sharedctypes import RawArray
+    return RawArray(typecode_or_type, size_or_initializer)
+
+def Value(typecode_or_type, *args, **kwds):
+    '''
+    Returns a synchronized shared object
+    '''
+    from multiprocessing.sharedctypes import Value
+    return Value(typecode_or_type, *args, **kwds)
+
+def Array(typecode_or_type, size_or_initializer, **kwds):
+    '''
+    Returns a synchronized shared array
+    '''
+    from multiprocessing.sharedctypes import Array
+    return Array(typecode_or_type, size_or_initializer, **kwds)
+
+#
+#
+#
+
+if sys.platform == 'win32':
+
+    def set_executable(executable):
+        '''
+        Sets the path to a python.exe or pythonw.exe binary used to run
+        child processes on Windows instead of sys.executable.
+        Useful for people embedding Python.
+        '''
+        from multiprocessing.forking import set_executable
+        set_executable(executable)
+
+    __all__ += ['set_executable']