#
# Module to allow connection and socket objects to be transferred
# between processes
#
# multiprocessing/reduction.py
#
# Copyright (c) 2006-2008, R Oudkerk
# Licensed to PSF under a Contributor Agreement.
#
from __future__ import absolute_import
import os
import sys
import socket
import threading
from pickle import Pickler
from .. import current_process
from .._ext import _billiard, win32
from ..util import register_after_fork, debug, sub_debug
is_win32 = sys.platform == 'win32'
is_pypy = hasattr(sys, 'pypy_version_info')
is_py3k = sys.version_info[0] == 3
if not(is_win32 or is_pypy or is_py3k or hasattr(_billiard, 'recvfd')):
raise ImportError('pickling of connections not supported')
close = win32.CloseHandle if sys.platform == 'win32' else os.close
__all__ = []
# globals set later
_listener = None
_lock = None
_cache = set()
#
# ForkingPickler
#
class ForkingPickler(Pickler): # noqa
dispatch = Pickler.dispatch.copy()
@classmethod
def register(cls, type, reduce):
def dispatcher(self, obj):
rv = reduce(obj)
self.save_reduce(obj=obj, *rv)
cls.dispatch[type] = dispatcher
def _reduce_method(m): # noqa
if m.__self__ is None:
return getattr, (m.__self__.__class__, m.__func__.__name__)
else:
return getattr, (m.__self__, m.__func__.__name__)
ForkingPickler.register(type(ForkingPickler.save), _reduce_method)
def _reduce_method_descriptor(m):
return getattr, (m.__objclass__, m.__name__)
ForkingPickler.register(type(list.append), _reduce_method_descriptor)
ForkingPickler.register(type(int.__add__), _reduce_method_descriptor)
try:
from functools import partial
except ImportError:
pass
else:
def _reduce_partial(p):
return _rebuild_partial, (p.func, p.args, p.keywords or {})
def _rebuild_partial(func, args, keywords):
return partial(func, *args, **keywords)
ForkingPickler.register(partial, _reduce_partial)
def dump(obj, file, protocol=None):
ForkingPickler(file, protocol).dump(obj)
#
# Platform specific definitions
#
if sys.platform == 'win32':
# XXX Should this subprocess import be here?
import _subprocess # noqa
def send_handle(conn, handle, destination_pid):
from ..forking import duplicate
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): # noqa
_billiard.sendfd(conn.fileno(), handle)
def recv_handle(conn): # noqa
return _billiard.recvfd(conn.fileno())
#
# Support for a per-process server thread which caches pickled handles
#
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:
from ..connection import Listener
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():
sub_warning('thread for sharing handles raised exception',
exc_info=True)
#
# Functions to be used for pickling/unpickling objects with handles
#
def reduce_handle(handle):
from ..forking import Popen, duplicate
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):
from ..connection import Client
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 `_billiard.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 _billiard.Connection(
handle, readable=readable, writable=writable
)
# 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 `_billiard.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 _billiard.PipeConnection(
handle, readable=readable, writable=writable
)