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#
# A higher level module for using sockets (or Windows named pipes)
#
# multiprocessing/connection.py
#
# Copyright (c) 2006-2008, R Oudkerk
# Licensed to PSF under a Contributor Agreement.
#
__all__ = [ 'Client', 'Listener', 'Pipe', 'wait' ]
import io
import os
import sys
import socket
import struct
import time
import tempfile
import itertools
import _multiprocessing
from . import util
from . import AuthenticationError, BufferTooShort
from .context import reduction
_ForkingPickler = reduction.ForkingPickler
try:
import _winapi
from _winapi import WAIT_OBJECT_0, WAIT_ABANDONED_0, WAIT_TIMEOUT, INFINITE
except ImportError:
if sys.platform == 'win32':
raise
_winapi = None
#
#
#
BUFSIZE = 8192
# A very generous timeout when it comes to local connections...
CONNECTION_TIMEOUT = 20.
_mmap_counter = itertools.count()
default_family = 'AF_INET'
families = ['AF_INET']
if hasattr(socket, 'AF_UNIX'):
default_family = 'AF_UNIX'
families += ['AF_UNIX']
if sys.platform == 'win32':
default_family = 'AF_PIPE'
families += ['AF_PIPE']
def _init_timeout(timeout=CONNECTION_TIMEOUT):
return time.monotonic() + timeout
def _check_timeout(t):
return time.monotonic() > t
#
#
#
def arbitrary_address(family):
'''
Return an arbitrary free address for the given family
'''
if family == 'AF_INET':
return ('localhost', 0)
elif family == 'AF_UNIX':
return tempfile.mktemp(prefix='listener-', dir=util.get_temp_dir())
elif family == 'AF_PIPE':
return tempfile.mktemp(prefix=r'\\.\pipe\pyc-%d-%d-' %
(os.getpid(), next(_mmap_counter)), dir="")
else:
raise ValueError('unrecognized family')
def _validate_family(family):
'''
Checks if the family is valid for the current environment.
'''
if sys.platform != 'win32' and family == 'AF_PIPE':
raise ValueError('Family %s is not recognized.' % family)
if sys.platform == 'win32' and family == 'AF_UNIX':
# double check
if not hasattr(socket, family):
raise ValueError('Family %s is not recognized.' % family)
def address_type(address):
'''
Return the types of the address
This can be 'AF_INET', 'AF_UNIX', or 'AF_PIPE'
'''
if type(address) == tuple:
return 'AF_INET'
elif type(address) is str and address.startswith('\\\\'):
return 'AF_PIPE'
elif type(address) is str:
return 'AF_UNIX'
else:
raise ValueError('address type of %r unrecognized' % address)
#
# Connection classes
#
class _ConnectionBase:
_handle = None
def __init__(self, handle, readable=True, writable=True):
handle = handle.__index__()
if handle < 0:
raise ValueError("invalid handle")
if not readable and not writable:
raise ValueError(
"at least one of `readable` and `writable` must be True")
self._handle = handle
self._readable = readable
self._writable = writable
# XXX should we use util.Finalize instead of a __del__?
def __del__(self):
if self._handle is not None:
self._close()
def _check_closed(self):
if self._handle is None:
raise OSError("handle is closed")
def _check_readable(self):
if not self._readable:
raise OSError("connection is write-only")
def _check_writable(self):
if not self._writable:
raise OSError("connection is read-only")
def _bad_message_length(self):
if self._writable:
self._readable = False
else:
self.close()
raise OSError("bad message length")
@property
def closed(self):
"""True if the connection is closed"""
return self._handle is None
@property
def readable(self):
"""True if the connection is readable"""
return self._readable
@property
def writable(self):
"""True if the connection is writable"""
return self._writable
def fileno(self):
"""File descriptor or handle of the connection"""
self._check_closed()
return self._handle
def close(self):
"""Close the connection"""
if self._handle is not None:
try:
self._close()
finally:
self._handle = None
def send_bytes(self, buf, offset=0, size=None):
"""Send the bytes data from a bytes-like object"""
self._check_closed()
self._check_writable()
m = memoryview(buf)
# HACK for byte-indexing of non-bytewise buffers (e.g. array.array)
if m.itemsize > 1:
m = memoryview(bytes(m))
n = len(m)
if offset < 0:
raise ValueError("offset is negative")
if n < offset:
raise ValueError("buffer length < offset")
if size is None:
size = n - offset
elif size < 0:
raise ValueError("size is negative")
elif offset + size > n:
raise ValueError("buffer length < offset + size")
self._send_bytes(m[offset:offset + size])
def send(self, obj):
"""Send a (picklable) object"""
self._check_closed()
self._check_writable()
self._send_bytes(_ForkingPickler.dumps(obj))
def recv_bytes(self, maxlength=None):
"""
Receive bytes data as a bytes object.
"""
self._check_closed()
self._check_readable()
if maxlength is not None and maxlength < 0:
raise ValueError("negative maxlength")
buf = self._recv_bytes(maxlength)
if buf is None:
self._bad_message_length()
return buf.getvalue()
def recv_bytes_into(self, buf, offset=0):
"""
Receive bytes data into a writeable bytes-like object.
Return the number of bytes read.
"""
self._check_closed()
self._check_readable()
with memoryview(buf) as m:
# Get bytesize of arbitrary buffer
itemsize = m.itemsize
bytesize = itemsize * len(m)
if offset < 0:
raise ValueError("negative offset")
elif offset > bytesize:
raise ValueError("offset too large")
result = self._recv_bytes()
size = result.tell()
if bytesize < offset + size:
raise BufferTooShort(result.getvalue())
# Message can fit in dest
result.seek(0)
result.readinto(m[offset // itemsize :
(offset + size) // itemsize])
return size
def recv(self):
"""Receive a (picklable) object"""
self._check_closed()
self._check_readable()
buf = self._recv_bytes()
return _ForkingPickler.loads(buf.getbuffer())
def poll(self, timeout=0.0):
"""Whether there is any input available to be read"""
self._check_closed()
self._check_readable()
return self._poll(timeout)
def __enter__(self):
return self
def __exit__(self, exc_type, exc_value, exc_tb):
self.close()
if _winapi:
class PipeConnection(_ConnectionBase):
"""
Connection class based on a Windows named pipe.
Overlapped I/O is used, so the handles must have been created
with FILE_FLAG_OVERLAPPED.
"""
_got_empty_message = False
def _close(self, _CloseHandle=_winapi.CloseHandle):
_CloseHandle(self._handle)
def _send_bytes(self, buf):
ov, err = _winapi.WriteFile(self._handle, buf, overlapped=True)
try:
if err == _winapi.ERROR_IO_PENDING:
waitres = _winapi.WaitForMultipleObjects(
[ov.event], False, INFINITE)
assert waitres == WAIT_OBJECT_0
except:
ov.cancel()
raise
finally:
nwritten, err = ov.GetOverlappedResult(True)
assert err == 0
assert nwritten == len(buf)
def _recv_bytes(self, maxsize=None):
if self._got_empty_message:
self._got_empty_message = False
return io.BytesIO()
else:
bsize = 128 if maxsize is None else min(maxsize, 128)
try:
ov, err = _winapi.ReadFile(self._handle, bsize,
overlapped=True)
try:
if err == _winapi.ERROR_IO_PENDING:
waitres = _winapi.WaitForMultipleObjects(
[ov.event], False, INFINITE)
assert waitres == WAIT_OBJECT_0
except:
ov.cancel()
raise
finally:
nread, err = ov.GetOverlappedResult(True)
if err == 0:
f = io.BytesIO()
f.write(ov.getbuffer())
return f
elif err == _winapi.ERROR_MORE_DATA:
return self._get_more_data(ov, maxsize)
except OSError as e:
if e.winerror == _winapi.ERROR_BROKEN_PIPE:
raise EOFError
else:
raise
raise RuntimeError("shouldn't get here; expected KeyboardInterrupt")
def _poll(self, timeout):
if (self._got_empty_message or
_winapi.PeekNamedPipe(self._handle)[0] != 0):
return True
return bool(wait([self], timeout))
def _get_more_data(self, ov, maxsize):
buf = ov.getbuffer()
f = io.BytesIO()
f.write(buf)
left = _winapi.PeekNamedPipe(self._handle)[1]
assert left > 0
if maxsize is not None and len(buf) + left > maxsize:
self._bad_message_length()
ov, err = _winapi.ReadFile(self._handle, left, overlapped=True)
rbytes, err = ov.GetOverlappedResult(True)
assert err == 0
assert rbytes == left
f.write(ov.getbuffer())
return f
class Connection(_ConnectionBase):
"""
Connection class based on an arbitrary file descriptor (Unix only), or
a socket handle (Windows).
"""
if _winapi:
def _close(self, _close=_multiprocessing.closesocket):
_close(self._handle)
_write = _multiprocessing.send
_read = _multiprocessing.recv
else:
def _close(self, _close=os.close):
_close(self._handle)
_write = os.write
_read = os.read
def _send(self, buf, write=_write):
remaining = len(buf)
while True:
n = write(self._handle, buf)
remaining -= n
if remaining == 0:
break
buf = buf[n:]
def _recv(self, size, read=_read):
buf = io.BytesIO()
handle = self._handle
remaining = size
while remaining > 0:
chunk = read(handle, remaining)
n = len(chunk)
if n == 0:
if remaining == size:
raise EOFError
else:
raise OSError("got end of file during message")
buf.write(chunk)
remaining -= n
return buf
def _send_bytes(self, buf):
n = len(buf)
# For wire compatibility with 3.2 and lower
header = struct.pack("!i", n)
if n > 16384:
# The payload is large so Nagle's algorithm won't be triggered
# and we'd better avoid the cost of concatenation.
self._send(header)
self._send(buf)
else:
# Issue #20540: concatenate before sending, to avoid delays due
# to Nagle's algorithm on a TCP socket.
# Also note we want to avoid sending a 0-length buffer separately,
# to avoid "broken pipe" errors if the other end closed the pipe.
self._send(header + buf)
def _recv_bytes(self, maxsize=None):
buf = self._recv(4)
size, = struct.unpack("!i", buf.getvalue())
if maxsize is not None and size > maxsize:
return None
return self._recv(size)
def _poll(self, timeout):
r = wait([self], timeout)
return bool(r)
#
# Public functions
#
class Listener(object):
'''
Returns a listener object.
This is a wrapper for a bound socket which is 'listening' for
connections, or for a Windows named pipe.
'''
def __init__(self, address=None, family=None, backlog=1, authkey=None):
family = family or (address and address_type(address)) \
or default_family
address = address or arbitrary_address(family)
_validate_family(family)
if family == 'AF_PIPE':
self._listener = PipeListener(address, backlog)
else:
self._listener = SocketListener(address, family, backlog)
if authkey is not None and not isinstance(authkey, bytes):
raise TypeError('authkey should be a byte string')
self._authkey = authkey
def accept(self):
'''
Accept a connection on the bound socket or named pipe of `self`.
Returns a `Connection` object.
'''
if self._listener is None:
raise OSError('listener is closed')
c = self._listener.accept()
if self._authkey:
deliver_challenge(c, self._authkey)
answer_challenge(c, self._authkey)
return c
def close(self):
'''
Close the bound socket or named pipe of `self`.
'''
listener = self._listener
if listener is not None:
self._listener = None
listener.close()
@property
def address(self):
return self._listener._address
@property
def last_accepted(self):
return self._listener._last_accepted
def __enter__(self):
return self
def __exit__(self, exc_type, exc_value, exc_tb):
self.close()
def Client(address, family=None, authkey=None):
'''
Returns a connection to the address of a `Listener`
'''
family = family or address_type(address)
_validate_family(family)
if family == 'AF_PIPE':
c = PipeClient(address)
else:
c = SocketClient(address)
if authkey is not None and not isinstance(authkey, bytes):
raise TypeError('authkey should be a byte string')
if authkey is not None:
answer_challenge(c, authkey)
deliver_challenge(c, authkey)
return c
if sys.platform != 'win32':
def Pipe(duplex=True):
'''
Returns pair of connection objects at either end of a pipe
'''
if duplex:
s1, s2 = socket.socketpair()
s1.setblocking(True)
s2.setblocking(True)
c1 = Connection(s1.detach())
c2 = Connection(s2.detach())
else:
fd1, fd2 = os.pipe()
c1 = Connection(fd1, writable=False)
c2 = Connection(fd2, readable=False)
return c1, c2
else:
def Pipe(duplex=True):
'''
Returns pair of connection objects at either end of a pipe
'''
address = arbitrary_address('AF_PIPE')
if duplex:
openmode = _winapi.PIPE_ACCESS_DUPLEX
access = _winapi.GENERIC_READ | _winapi.GENERIC_WRITE
obsize, ibsize = BUFSIZE, BUFSIZE
else:
openmode = _winapi.PIPE_ACCESS_INBOUND
access = _winapi.GENERIC_WRITE
obsize, ibsize = 0, BUFSIZE
h1 = _winapi.CreateNamedPipe(
address, openmode | _winapi.FILE_FLAG_OVERLAPPED |
_winapi.FILE_FLAG_FIRST_PIPE_INSTANCE,
_winapi.PIPE_TYPE_MESSAGE | _winapi.PIPE_READMODE_MESSAGE |
_winapi.PIPE_WAIT,
1, obsize, ibsize, _winapi.NMPWAIT_WAIT_FOREVER,
# default security descriptor: the handle cannot be inherited
_winapi.NULL
)
h2 = _winapi.CreateFile(
address, access, 0, _winapi.NULL, _winapi.OPEN_EXISTING,
_winapi.FILE_FLAG_OVERLAPPED, _winapi.NULL
)
_winapi.SetNamedPipeHandleState(
h2, _winapi.PIPE_READMODE_MESSAGE, None, None
)
overlapped = _winapi.ConnectNamedPipe(h1, overlapped=True)
_, err = overlapped.GetOverlappedResult(True)
assert err == 0
c1 = PipeConnection(h1, writable=duplex)
c2 = PipeConnection(h2, readable=duplex)
return c1, c2
#
# Definitions for connections based on sockets
#
class SocketListener(object):
'''
Representation of a socket which is bound to an address and listening
'''
def __init__(self, address, family, backlog=1):
self._socket = socket.socket(getattr(socket, family))
try:
# SO_REUSEADDR has different semantics on Windows (issue #2550).
if os.name == 'posix':
self._socket.setsockopt(socket.SOL_SOCKET,
socket.SO_REUSEADDR, 1)
self._socket.setblocking(True)
self._socket.bind(address)
self._socket.listen(backlog)
self._address = self._socket.getsockname()
except OSError:
self._socket.close()
raise
self._family = family
self._last_accepted = None
if family == 'AF_UNIX':
self._unlink = util.Finalize(
self, os.unlink, args=(address,), exitpriority=0
)
else:
self._unlink = None
def accept(self):
s, self._last_accepted = self._socket.accept()
s.setblocking(True)
return Connection(s.detach())
def close(self):
try:
self._socket.close()
finally:
unlink = self._unlink
if unlink is not None:
self._unlink = None
unlink()
def SocketClient(address):
'''
Return a connection object connected to the socket given by `address`
'''
family = address_type(address)
with socket.socket( getattr(socket, family) ) as s:
s.setblocking(True)
s.connect(address)
return Connection(s.detach())
#
# Definitions for connections based on named pipes
#
if sys.platform == 'win32':
class PipeListener(object):
'''
Representation of a named pipe
'''
def __init__(self, address, backlog=None):
self._address = address
self._handle_queue = [self._new_handle(first=True)]
self._last_accepted = None
util.sub_debug('listener created with address=%r', self._address)
self.close = util.Finalize(
self, PipeListener._finalize_pipe_listener,
args=(self._handle_queue, self._address), exitpriority=0
)
def _new_handle(self, first=False):
flags = _winapi.PIPE_ACCESS_DUPLEX | _winapi.FILE_FLAG_OVERLAPPED
if first:
flags |= _winapi.FILE_FLAG_FIRST_PIPE_INSTANCE
return _winapi.CreateNamedPipe(
self._address, flags,
_winapi.PIPE_TYPE_MESSAGE | _winapi.PIPE_READMODE_MESSAGE |
_winapi.PIPE_WAIT,
_winapi.PIPE_UNLIMITED_INSTANCES, BUFSIZE, BUFSIZE,
_winapi.NMPWAIT_WAIT_FOREVER, _winapi.NULL
)
def accept(self):
self._handle_queue.append(self._new_handle())
handle = self._handle_queue.pop(0)
try:
ov = _winapi.ConnectNamedPipe(handle, overlapped=True)
except OSError as e:
if e.winerror != _winapi.ERROR_NO_DATA:
raise
# ERROR_NO_DATA can occur if a client has already connected,
# written data and then disconnected -- see Issue 14725.
else:
try:
res = _winapi.WaitForMultipleObjects(
[ov.event], False, INFINITE)
except:
ov.cancel()
_winapi.CloseHandle(handle)
raise
finally:
_, err = ov.GetOverlappedResult(True)
assert err == 0
return PipeConnection(handle)
@staticmethod
def _finalize_pipe_listener(queue, address):
util.sub_debug('closing listener with address=%r', address)
for handle in queue:
_winapi.CloseHandle(handle)
def PipeClient(address):
'''
Return a connection object connected to the pipe given by `address`
'''
t = _init_timeout()
while 1:
try:
_winapi.WaitNamedPipe(address, 1000)
h = _winapi.CreateFile(
address, _winapi.GENERIC_READ | _winapi.GENERIC_WRITE,
0, _winapi.NULL, _winapi.OPEN_EXISTING,
_winapi.FILE_FLAG_OVERLAPPED, _winapi.NULL
)
except OSError as e:
if e.winerror not in (_winapi.ERROR_SEM_TIMEOUT,
_winapi.ERROR_PIPE_BUSY) or _check_timeout(t):
raise
else:
break
else:
raise
_winapi.SetNamedPipeHandleState(
h, _winapi.PIPE_READMODE_MESSAGE, None, None
)
return PipeConnection(h)
#
# Authentication stuff
#
MESSAGE_LENGTH = 20
CHALLENGE = b'#CHALLENGE#'
WELCOME = b'#WELCOME#'
FAILURE = b'#FAILURE#'
def deliver_challenge(connection, authkey):
import hmac
if not isinstance(authkey, bytes):
raise ValueError(
"Authkey must be bytes, not {0!s}".format(type(authkey)))
message = os.urandom(MESSAGE_LENGTH)
connection.send_bytes(CHALLENGE + message)
digest = hmac.new(authkey, message, 'md5').digest()
response = connection.recv_bytes(256) # reject large message
if response == digest:
connection.send_bytes(WELCOME)
else:
connection.send_bytes(FAILURE)
raise AuthenticationError('digest received was wrong')
def answer_challenge(connection, authkey):
import hmac
if not isinstance(authkey, bytes):
raise ValueError(
"Authkey must be bytes, not {0!s}".format(type(authkey)))
message = connection.recv_bytes(256) # reject large message
assert message[:len(CHALLENGE)] == CHALLENGE, 'message = %r' % message
message = message[len(CHALLENGE):]
digest = hmac.new(authkey, message, 'md5').digest()
connection.send_bytes(digest)
response = connection.recv_bytes(256) # reject large message
if response != WELCOME:
raise AuthenticationError('digest sent was rejected')
#
# Support for using xmlrpclib for serialization
#
class ConnectionWrapper(object):
def __init__(self, conn, dumps, loads):
self._conn = conn
self._dumps = dumps
self._loads = loads
for attr in ('fileno', 'close', 'poll', 'recv_bytes', 'send_bytes'):
obj = getattr(conn, attr)
setattr(self, attr, obj)
def send(self, obj):
s = self._dumps(obj)
self._conn.send_bytes(s)
def recv(self):
s = self._conn.recv_bytes()
return self._loads(s)
def _xml_dumps(obj):
return xmlrpclib.dumps((obj,), None, None, None, 1).encode('utf-8')
def _xml_loads(s):
(obj,), method = xmlrpclib.loads(s.decode('utf-8'))
return obj
class XmlListener(Listener):
def accept(self):
global xmlrpclib
import xmlrpc.client as xmlrpclib
obj = Listener.accept(self)
return ConnectionWrapper(obj, _xml_dumps, _xml_loads)
def XmlClient(*args, **kwds):
global xmlrpclib
import xmlrpc.client as xmlrpclib
return ConnectionWrapper(Client(*args, **kwds), _xml_dumps, _xml_loads)
#
# Wait
#
if sys.platform == 'win32':
def _exhaustive_wait(handles, timeout):
# Return ALL handles which are currently signalled. (Only
# returning the first signalled might create starvation issues.)
L = list(handles)
ready = []
while L:
res = _winapi.WaitForMultipleObjects(L, False, timeout)
if res == WAIT_TIMEOUT:
break
elif WAIT_OBJECT_0 <= res < WAIT_OBJECT_0 + len(L):
res -= WAIT_OBJECT_0
elif WAIT_ABANDONED_0 <= res < WAIT_ABANDONED_0 + len(L):
res -= WAIT_ABANDONED_0
else:
raise RuntimeError('Should not get here')
ready.append(L[res])
L = L[res+1:]
timeout = 0
return ready
_ready_errors = {_winapi.ERROR_BROKEN_PIPE, _winapi.ERROR_NETNAME_DELETED}
def wait(object_list, timeout=None):
'''
Wait till an object in object_list is ready/readable.
Returns list of those objects in object_list which are ready/readable.
'''
if timeout is None:
timeout = INFINITE
elif timeout < 0:
timeout = 0
else:
timeout = int(timeout * 1000 + 0.5)
object_list = list(object_list)
waithandle_to_obj = {}
ov_list = []
ready_objects = set()
ready_handles = set()
try:
for o in object_list:
try:
fileno = getattr(o, 'fileno')
except AttributeError:
waithandle_to_obj[o.__index__()] = o
else:
# start an overlapped read of length zero
try:
ov, err = _winapi.ReadFile(fileno(), 0, True)
except OSError as e:
ov, err = None, e.winerror
if err not in _ready_errors:
raise
if err == _winapi.ERROR_IO_PENDING:
ov_list.append(ov)
waithandle_to_obj[ov.event] = o
else:
# If o.fileno() is an overlapped pipe handle and
# err == 0 then there is a zero length message
# in the pipe, but it HAS NOT been consumed...
if ov and sys.getwindowsversion()[:2] >= (6, 2):
# ... except on Windows 8 and later, where
# the message HAS been consumed.
try:
_, err = ov.GetOverlappedResult(False)
except OSError as e:
err = e.winerror
if not err and hasattr(o, '_got_empty_message'):
o._got_empty_message = True
ready_objects.add(o)
timeout = 0
ready_handles = _exhaustive_wait(waithandle_to_obj.keys(), timeout)
finally:
# request that overlapped reads stop
for ov in ov_list:
ov.cancel()
# wait for all overlapped reads to stop
for ov in ov_list:
try:
_, err = ov.GetOverlappedResult(True)
except OSError as e:
err = e.winerror
if err not in _ready_errors:
raise
if err != _winapi.ERROR_OPERATION_ABORTED:
o = waithandle_to_obj[ov.event]
ready_objects.add(o)
if err == 0:
# If o.fileno() is an overlapped pipe handle then
# a zero length message HAS been consumed.
if hasattr(o, '_got_empty_message'):
o._got_empty_message = True
ready_objects.update(waithandle_to_obj[h] for h in ready_handles)
return [o for o in object_list if o in ready_objects]
else:
import selectors
# poll/select have the advantage of not requiring any extra file
# descriptor, contrarily to epoll/kqueue (also, they require a single
# syscall).
if hasattr(selectors, 'PollSelector'):
_WaitSelector = selectors.PollSelector
else:
_WaitSelector = selectors.SelectSelector
def wait(object_list, timeout=None):
'''
Wait till an object in object_list is ready/readable.
Returns list of those objects in object_list which are ready/readable.
'''
with _WaitSelector() as selector:
for obj in object_list:
selector.register(obj, selectors.EVENT_READ)
if timeout is not None:
deadline = time.monotonic() + timeout
while True:
ready = selector.select(timeout)
if ready:
return [key.fileobj for (key, events) in ready]
else:
if timeout is not None:
timeout = deadline - time.monotonic()
if timeout < 0:
return ready
#
# Make connection and socket objects sharable if possible
#
if sys.platform == 'win32':
def reduce_connection(conn):
handle = conn.fileno()
with socket.fromfd(handle, socket.AF_INET, socket.SOCK_STREAM) as s:
from . import resource_sharer
ds = resource_sharer.DupSocket(s)
return rebuild_connection, (ds, conn.readable, conn.writable)
def rebuild_connection(ds, readable, writable):
sock = ds.detach()
return Connection(sock.detach(), readable, writable)
reduction.register(Connection, reduce_connection)
def reduce_pipe_connection(conn):
access = ((_winapi.FILE_GENERIC_READ if conn.readable else 0) |
(_winapi.FILE_GENERIC_WRITE if conn.writable else 0))
dh = reduction.DupHandle(conn.fileno(), access)
return rebuild_pipe_connection, (dh, conn.readable, conn.writable)
def rebuild_pipe_connection(dh, readable, writable):
handle = dh.detach()
return PipeConnection(handle, readable, writable)
reduction.register(PipeConnection, reduce_pipe_connection)
else:
def reduce_connection(conn):
df = reduction.DupFd(conn.fileno())
return rebuild_connection, (df, conn.readable, conn.writable)
def rebuild_connection(df, readable, writable):
fd = df.detach()
return Connection(fd, readable, writable)
reduction.register(Connection, reduce_connection)