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Allow sending more than 2 GB at once on a multiprocessing connection on non-Windows systems. https://stackoverflow.com/questions/47776486/python-struct-error-i-format-requires-2147483648-number-2147483647
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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) | |
if n > 0x7fffffff: | |
pre_header = struct.pack("!i", -1) | |
header = struct.pack("!Q", n) | |
self._send(pre_header) | |
# 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) | |
''' | |
# For wire compatibility with 3.7 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 size == -1: | |
buf = self._recv(8) | |
size, = struct.unpack("!Q", 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) |
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