cpython/Lib/asyncio/windows_events.py

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"""Selector and proactor event loops for Windows."""
import _winapi
import errno
import math
import socket
import struct
import weakref
from . import events
from . import base_subprocess
from . import futures
from . import proactor_events
from . import selector_events
from . import tasks
from . import windows_utils
from . import _overlapped
from .coroutines import coroutine
from .log import logger
__all__ = ['SelectorEventLoop', 'ProactorEventLoop', 'IocpProactor',
'DefaultEventLoopPolicy',
]
NULL = 0
INFINITE = 0xffffffff
ERROR_CONNECTION_REFUSED = 1225
ERROR_CONNECTION_ABORTED = 1236
class _OverlappedFuture(futures.Future):
"""Subclass of Future which represents an overlapped operation.
Cancelling it will immediately cancel the overlapped operation.
"""
def __init__(self, ov, *, loop=None):
super().__init__(loop=loop)
self.ov = ov
def cancel(self):
try:
self.ov.cancel()
except OSError:
pass
return super().cancel()
class _WaitHandleFuture(futures.Future):
"""Subclass of Future which represents a wait handle."""
def __init__(self, wait_handle, *, loop=None):
super().__init__(loop=loop)
self._wait_handle = wait_handle
def cancel(self):
super().cancel()
try:
_overlapped.UnregisterWait(self._wait_handle)
except OSError as e:
if e.winerror != _overlapped.ERROR_IO_PENDING:
raise
class PipeServer(object):
"""Class representing a pipe server.
This is much like a bound, listening socket.
"""
def __init__(self, address):
self._address = address
self._free_instances = weakref.WeakSet()
self._pipe = self._server_pipe_handle(True)
def _get_unconnected_pipe(self):
# Create new instance and return previous one. This ensures
# that (until the server is closed) there is always at least
# one pipe handle for address. Therefore if a client attempt
# to connect it will not fail with FileNotFoundError.
tmp, self._pipe = self._pipe, self._server_pipe_handle(False)
return tmp
def _server_pipe_handle(self, first):
# Return a wrapper for a new pipe handle.
if self._address is None:
return None
flags = _winapi.PIPE_ACCESS_DUPLEX | _winapi.FILE_FLAG_OVERLAPPED
if first:
flags |= _winapi.FILE_FLAG_FIRST_PIPE_INSTANCE
h = _winapi.CreateNamedPipe(
self._address, flags,
_winapi.PIPE_TYPE_MESSAGE | _winapi.PIPE_READMODE_MESSAGE |
_winapi.PIPE_WAIT,
_winapi.PIPE_UNLIMITED_INSTANCES,
windows_utils.BUFSIZE, windows_utils.BUFSIZE,
_winapi.NMPWAIT_WAIT_FOREVER, _winapi.NULL)
pipe = windows_utils.PipeHandle(h)
self._free_instances.add(pipe)
return pipe
def close(self):
# Close all instances which have not been connected to by a client.
if self._address is not None:
for pipe in self._free_instances:
pipe.close()
self._pipe = None
self._address = None
self._free_instances.clear()
__del__ = close
class _WindowsSelectorEventLoop(selector_events.BaseSelectorEventLoop):
"""Windows version of selector event loop."""
def _socketpair(self):
return windows_utils.socketpair()
class ProactorEventLoop(proactor_events.BaseProactorEventLoop):
"""Windows version of proactor event loop using IOCP."""
def __init__(self, proactor=None):
if proactor is None:
proactor = IocpProactor()
super().__init__(proactor)
def _socketpair(self):
return windows_utils.socketpair()
@coroutine
def create_pipe_connection(self, protocol_factory, address):
f = self._proactor.connect_pipe(address)
pipe = yield from f
protocol = protocol_factory()
trans = self._make_duplex_pipe_transport(pipe, protocol,
extra={'addr': address})
return trans, protocol
@coroutine
def start_serving_pipe(self, protocol_factory, address):
server = PipeServer(address)
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def loop(f=None):
pipe = None
try:
if f:
pipe = f.result()
server._free_instances.discard(pipe)
protocol = protocol_factory()
self._make_duplex_pipe_transport(
pipe, protocol, extra={'addr': address})
pipe = server._get_unconnected_pipe()
if pipe is None:
return
f = self._proactor.accept_pipe(pipe)
except OSError as exc:
if pipe and pipe.fileno() != -1:
self.call_exception_handler({
'message': 'Pipe accept failed',
'exception': exc,
'pipe': pipe,
})
pipe.close()
except futures.CancelledError:
if pipe:
pipe.close()
else:
f.add_done_callback(loop)
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self.call_soon(loop)
return [server]
@coroutine
def _make_subprocess_transport(self, protocol, args, shell,
stdin, stdout, stderr, bufsize,
extra=None, **kwargs):
transp = _WindowsSubprocessTransport(self, protocol, args, shell,
stdin, stdout, stderr, bufsize,
extra=extra, **kwargs)
yield from transp._post_init()
return transp
class IocpProactor:
"""Proactor implementation using IOCP."""
def __init__(self, concurrency=0xffffffff):
self._loop = None
self._results = []
self._iocp = _overlapped.CreateIoCompletionPort(
_overlapped.INVALID_HANDLE_VALUE, NULL, 0, concurrency)
self._cache = {}
self._registered = weakref.WeakSet()
self._stopped_serving = weakref.WeakSet()
def set_loop(self, loop):
self._loop = loop
def select(self, timeout=None):
if not self._results:
self._poll(timeout)
tmp = self._results
self._results = []
return tmp
def recv(self, conn, nbytes, flags=0):
self._register_with_iocp(conn)
ov = _overlapped.Overlapped(NULL)
if isinstance(conn, socket.socket):
ov.WSARecv(conn.fileno(), nbytes, flags)
else:
ov.ReadFile(conn.fileno(), nbytes)
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def finish_recv(trans, key, ov):
try:
return ov.getresult()
except OSError as exc:
if exc.winerror == _overlapped.ERROR_NETNAME_DELETED:
raise ConnectionResetError(*exc.args)
else:
raise
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return self._register(ov, conn, finish_recv)
def send(self, conn, buf, flags=0):
self._register_with_iocp(conn)
ov = _overlapped.Overlapped(NULL)
if isinstance(conn, socket.socket):
ov.WSASend(conn.fileno(), buf, flags)
else:
ov.WriteFile(conn.fileno(), buf)
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def finish_send(trans, key, ov):
try:
return ov.getresult()
except OSError as exc:
if exc.winerror == _overlapped.ERROR_NETNAME_DELETED:
raise ConnectionResetError(*exc.args)
else:
raise
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return self._register(ov, conn, finish_send)
def accept(self, listener):
self._register_with_iocp(listener)
conn = self._get_accept_socket(listener.family)
ov = _overlapped.Overlapped(NULL)
ov.AcceptEx(listener.fileno(), conn.fileno())
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def finish_accept(trans, key, ov):
ov.getresult()
# Use SO_UPDATE_ACCEPT_CONTEXT so getsockname() etc work.
buf = struct.pack('@P', listener.fileno())
conn.setsockopt(socket.SOL_SOCKET,
_overlapped.SO_UPDATE_ACCEPT_CONTEXT, buf)
conn.settimeout(listener.gettimeout())
return conn, conn.getpeername()
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@coroutine
def accept_coro(future, conn):
# Coroutine closing the accept socket if the future is cancelled
try:
yield from future
except futures.CancelledError:
conn.close()
raise
future = self._register(ov, listener, finish_accept)
coro = accept_coro(future, conn)
tasks.async(coro, loop=self._loop)
return future
def connect(self, conn, address):
self._register_with_iocp(conn)
# The socket needs to be locally bound before we call ConnectEx().
try:
_overlapped.BindLocal(conn.fileno(), conn.family)
except OSError as e:
if e.winerror != errno.WSAEINVAL:
raise
# Probably already locally bound; check using getsockname().
if conn.getsockname()[1] == 0:
raise
ov = _overlapped.Overlapped(NULL)
ov.ConnectEx(conn.fileno(), address)
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def finish_connect(trans, key, ov):
ov.getresult()
# Use SO_UPDATE_CONNECT_CONTEXT so getsockname() etc work.
conn.setsockopt(socket.SOL_SOCKET,
_overlapped.SO_UPDATE_CONNECT_CONTEXT, 0)
return conn
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return self._register(ov, conn, finish_connect)
def accept_pipe(self, pipe):
self._register_with_iocp(pipe)
ov = _overlapped.Overlapped(NULL)
ov.ConnectNamedPipe(pipe.fileno())
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def finish_accept_pipe(trans, key, ov):
ov.getresult()
return pipe
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return self._register(ov, pipe, finish_accept_pipe)
def connect_pipe(self, address):
ov = _overlapped.Overlapped(NULL)
ov.WaitNamedPipeAndConnect(address, self._iocp, ov.address)
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def finish_connect_pipe(err, handle, ov):
# err, handle were arguments passed to PostQueuedCompletionStatus()
# in a function run in a thread pool.
if err == _overlapped.ERROR_SEM_TIMEOUT:
# Connection did not succeed within time limit.
msg = _overlapped.FormatMessage(err)
raise ConnectionRefusedError(0, msg, None, err)
elif err != 0:
msg = _overlapped.FormatMessage(err)
raise OSError(0, msg, None, err)
else:
return windows_utils.PipeHandle(handle)
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return self._register(ov, None, finish_connect_pipe, wait_for_post=True)
def wait_for_handle(self, handle, timeout=None):
if timeout is None:
ms = _winapi.INFINITE
else:
# RegisterWaitForSingleObject() has a resolution of 1 millisecond,
# round away from zero to wait *at least* timeout seconds.
ms = math.ceil(timeout * 1e3)
# We only create ov so we can use ov.address as a key for the cache.
ov = _overlapped.Overlapped(NULL)
wh = _overlapped.RegisterWaitWithQueue(
handle, self._iocp, ov.address, ms)
f = _WaitHandleFuture(wh, loop=self._loop)
def finish_wait_for_handle(trans, key, ov):
if not f.cancelled():
try:
_overlapped.UnregisterWait(wh)
except OSError as e:
if e.winerror != _overlapped.ERROR_IO_PENDING:
raise
# Note that this second wait means that we should only use
# this with handles types where a successful wait has no
# effect. So events or processes are all right, but locks
# or semaphores are not. Also note if the handle is
# signalled and then quickly reset, then we may return
# False even though we have not timed out.
return (_winapi.WaitForSingleObject(handle, 0) ==
_winapi.WAIT_OBJECT_0)
self._cache[ov.address] = (f, ov, None, finish_wait_for_handle)
return f
def _register_with_iocp(self, obj):
# To get notifications of finished ops on this objects sent to the
# completion port, were must register the handle.
if obj not in self._registered:
self._registered.add(obj)
_overlapped.CreateIoCompletionPort(obj.fileno(), self._iocp, 0, 0)
# XXX We could also use SetFileCompletionNotificationModes()
# to avoid sending notifications to completion port of ops
# that succeed immediately.
def _register(self, ov, obj, callback, wait_for_post=False):
# Return a future which will be set with the result of the
# operation when it completes. The future's value is actually
# the value returned by callback().
f = _OverlappedFuture(ov, loop=self._loop)
if ov.pending or wait_for_post:
# Register the overlapped operation for later. Note that
# we only store obj to prevent it from being garbage
# collected too early.
self._cache[ov.address] = (f, ov, obj, callback)
else:
# The operation has completed, so no need to postpone the
# work. We cannot take this short cut if we need the
# NumberOfBytes, CompletionKey values returned by
# PostQueuedCompletionStatus().
try:
value = callback(None, None, ov)
except OSError as e:
f.set_exception(e)
else:
f.set_result(value)
return f
def _get_accept_socket(self, family):
s = socket.socket(family)
s.settimeout(0)
return s
def _poll(self, timeout=None):
if timeout is None:
ms = INFINITE
elif timeout < 0:
raise ValueError("negative timeout")
else:
# GetQueuedCompletionStatus() has a resolution of 1 millisecond,
# round away from zero to wait *at least* timeout seconds.
ms = math.ceil(timeout * 1e3)
if ms >= INFINITE:
raise ValueError("timeout too big")
while True:
status = _overlapped.GetQueuedCompletionStatus(self._iocp, ms)
if status is None:
return
err, transferred, key, address = status
try:
f, ov, obj, callback = self._cache.pop(address)
except KeyError:
# key is either zero, or it is used to return a pipe
# handle which should be closed to avoid a leak.
if key not in (0, _overlapped.INVALID_HANDLE_VALUE):
_winapi.CloseHandle(key)
ms = 0
continue
if obj in self._stopped_serving:
f.cancel()
elif not f.cancelled():
try:
value = callback(transferred, key, ov)
except OSError as e:
f.set_exception(e)
self._results.append(f)
else:
f.set_result(value)
self._results.append(f)
ms = 0
def _stop_serving(self, obj):
# obj is a socket or pipe handle. It will be closed in
# BaseProactorEventLoop._stop_serving() which will make any
# pending operations fail quickly.
self._stopped_serving.add(obj)
def close(self):
# Cancel remaining registered operations.
for address, (f, ov, obj, callback) in list(self._cache.items()):
if obj is None:
# The operation was started with connect_pipe() which
# queues a task to Windows' thread pool. This cannot
# be cancelled, so just forget it.
del self._cache[address]
else:
try:
ov.cancel()
except OSError:
pass
while self._cache:
if not self._poll(1):
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logger.debug('taking long time to close proactor')
self._results = []
if self._iocp is not None:
_winapi.CloseHandle(self._iocp)
self._iocp = None
class _WindowsSubprocessTransport(base_subprocess.BaseSubprocessTransport):
def _start(self, args, shell, stdin, stdout, stderr, bufsize, **kwargs):
self._proc = windows_utils.Popen(
args, shell=shell, stdin=stdin, stdout=stdout, stderr=stderr,
bufsize=bufsize, **kwargs)
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def callback(f):
returncode = self._proc.poll()
self._process_exited(returncode)
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f = self._loop._proactor.wait_for_handle(int(self._proc._handle))
f.add_done_callback(callback)
SelectorEventLoop = _WindowsSelectorEventLoop
class _WindowsDefaultEventLoopPolicy(events.BaseDefaultEventLoopPolicy):
_loop_factory = SelectorEventLoop
DefaultEventLoopPolicy = _WindowsDefaultEventLoopPolicy