Staging
v0.8.1
v0.8.1
https://github.com/python/cpython
Tip revision: 1da43e5e916949c8e849e656d9d05fa4b9d6836c authored by Benjamin Peterson on 26 June 2009, 13:21:52 UTC
rearrange the sections of the README, so they'll hopefully be more in the order people will interested in
rearrange the sections of the README, so they'll hopefully be more in the order people will interested in
Tip revision: 1da43e5
reduction.py
#
# Module to allow connection and socket objects to be transferred
# between processes
#
# multiprocessing/reduction.py
#
# Copyright (c) 2006-2008, R Oudkerk --- see COPYING.txt
#
__all__ = []
import os
import sys
import socket
import threading
import _multiprocessing
from multiprocessing import current_process
from multiprocessing.forking import Popen, duplicate, close, ForkingPickler
from multiprocessing.util import register_after_fork, debug, sub_debug
from multiprocessing.connection import Client, Listener
#
#
#
if not(sys.platform == 'win32' or hasattr(_multiprocessing, 'recvfd')):
raise ImportError('pickling of connections not supported')
#
# Platform specific definitions
#
if sys.platform == 'win32':
import _subprocess
from ._multiprocessing import win32
def send_handle(conn, handle, destination_pid):
process_handle = win32.OpenProcess(
win32.PROCESS_ALL_ACCESS, False, destination_pid
)
try:
new_handle = duplicate(handle, process_handle)
conn.send(new_handle)
finally:
close(process_handle)
def recv_handle(conn):
return conn.recv()
else:
def send_handle(conn, handle, destination_pid):
_multiprocessing.sendfd(conn.fileno(), handle)
def recv_handle(conn):
return _multiprocessing.recvfd(conn.fileno())
#
# Support for a per-process server thread which caches pickled handles
#
_cache = set()
def _reset(obj):
global _lock, _listener, _cache
for h in _cache:
close(h)
_cache.clear()
_lock = threading.Lock()
_listener = None
_reset(None)
register_after_fork(_reset, _reset)
def _get_listener():
global _listener
if _listener is None:
_lock.acquire()
try:
if _listener is None:
debug('starting listener and thread for sending handles')
_listener = Listener(authkey=current_process().authkey)
t = threading.Thread(target=_serve)
t.daemon = True
t.start()
finally:
_lock.release()
return _listener
def _serve():
from .util import is_exiting, sub_warning
while 1:
try:
conn = _listener.accept()
handle_wanted, destination_pid = conn.recv()
_cache.remove(handle_wanted)
send_handle(conn, handle_wanted, destination_pid)
close(handle_wanted)
conn.close()
except:
if not is_exiting():
import traceback
sub_warning(
'thread for sharing handles raised exception :\n' +
'-'*79 + '\n' + traceback.format_exc() + '-'*79
)
#
# Functions to be used for pickling/unpickling objects with handles
#
def reduce_handle(handle):
if Popen.thread_is_spawning():
return (None, Popen.duplicate_for_child(handle), True)
dup_handle = duplicate(handle)
_cache.add(dup_handle)
sub_debug('reducing handle %d', handle)
return (_get_listener().address, dup_handle, False)
def rebuild_handle(pickled_data):
address, handle, inherited = pickled_data
if inherited:
return handle
sub_debug('rebuilding handle %d', handle)
conn = Client(address, authkey=current_process().authkey)
conn.send((handle, os.getpid()))
new_handle = recv_handle(conn)
conn.close()
return new_handle
#
# Register `_multiprocessing.Connection` with `ForkingPickler`
#
def reduce_connection(conn):
rh = reduce_handle(conn.fileno())
return rebuild_connection, (rh, conn.readable, conn.writable)
def rebuild_connection(reduced_handle, readable, writable):
handle = rebuild_handle(reduced_handle)
return _multiprocessing.Connection(
handle, readable=readable, writable=writable
)
ForkingPickler.register(_multiprocessing.Connection, reduce_connection)
#
# Register `socket.socket` with `ForkingPickler`
#
def fromfd(fd, family, type_, proto=0):
s = socket.fromfd(fd, family, type_, proto)
if s.__class__ is not socket.socket:
s = socket.socket(_sock=s)
return s
def reduce_socket(s):
reduced_handle = reduce_handle(s.fileno())
return rebuild_socket, (reduced_handle, s.family, s.type, s.proto)
def rebuild_socket(reduced_handle, family, type_, proto):
fd = rebuild_handle(reduced_handle)
_sock = fromfd(fd, family, type_, proto)
close(fd)
return _sock
ForkingPickler.register(socket.socket, reduce_socket)
#
# Register `_multiprocessing.PipeConnection` with `ForkingPickler`
#
if sys.platform == 'win32':
def reduce_pipe_connection(conn):
rh = reduce_handle(conn.fileno())
return rebuild_pipe_connection, (rh, conn.readable, conn.writable)
def rebuild_pipe_connection(reduced_handle, readable, writable):
handle = rebuild_handle(reduced_handle)
return _multiprocessing.PipeConnection(
handle, readable=readable, writable=writable
)
ForkingPickler.register(_multiprocessing.PipeConnection, reduce_pipe_connection)