cpython/Lib/asyncio/proactor_events.py

354 lines
11 KiB
Python

"""Event loop using a proactor and related classes.
A proactor is a "notify-on-completion" multiplexer. Currently a
proactor is only implemented on Windows with IOCP.
"""
import socket
from . import base_events
from . import constants
from . import futures
from . import transports
from .log import logger
class _ProactorBasePipeTransport(transports.BaseTransport):
"""Base class for pipe and socket transports."""
def __init__(self, loop, sock, protocol, waiter=None,
extra=None, server=None):
super().__init__(extra)
self._set_extra(sock)
self._loop = loop
self._sock = sock
self._protocol = protocol
self._server = server
self._buffer = []
self._read_fut = None
self._write_fut = None
self._conn_lost = 0
self._closing = False # Set when close() called.
self._eof_written = False
if self._server is not None:
self._server.attach(self)
self._loop.call_soon(self._protocol.connection_made, self)
if waiter is not None:
self._loop.call_soon(waiter.set_result, None)
def _set_extra(self, sock):
self._extra['pipe'] = sock
def close(self):
if self._closing:
return
self._closing = True
self._conn_lost += 1
if not self._buffer and self._write_fut is None:
self._loop.call_soon(self._call_connection_lost, None)
if self._read_fut is not None:
self._read_fut.cancel()
def _fatal_error(self, exc):
logger.exception('Fatal error for %s', self)
self._force_close(exc)
def _force_close(self, exc):
if self._closing:
return
self._closing = True
self._conn_lost += 1
if self._write_fut:
self._write_fut.cancel()
if self._read_fut:
self._read_fut.cancel()
self._write_fut = self._read_fut = None
self._buffer = []
self._loop.call_soon(self._call_connection_lost, exc)
def _call_connection_lost(self, exc):
try:
self._protocol.connection_lost(exc)
finally:
# XXX If there is a pending overlapped read on the other
# end then it may fail with ERROR_NETNAME_DELETED if we
# just close our end. First calling shutdown() seems to
# cure it, but maybe using DisconnectEx() would be better.
if hasattr(self._sock, 'shutdown'):
self._sock.shutdown(socket.SHUT_RDWR)
self._sock.close()
server = self._server
if server is not None:
server.detach(self)
self._server = None
class _ProactorReadPipeTransport(_ProactorBasePipeTransport,
transports.ReadTransport):
"""Transport for read pipes."""
def __init__(self, loop, sock, protocol, waiter=None,
extra=None, server=None):
super().__init__(loop, sock, protocol, waiter, extra, server)
self._read_fut = None
self._paused = False
self._loop.call_soon(self._loop_reading)
def pause_reading(self):
assert not self._closing, 'Cannot pause_reading() when closing'
assert not self._paused, 'Already paused'
self._paused = True
def resume_reading(self):
assert self._paused, 'Not paused'
self._paused = False
if self._closing:
return
self._loop.call_soon(self._loop_reading, self._read_fut)
def _loop_reading(self, fut=None):
if self._paused:
return
data = None
try:
if fut is not None:
assert self._read_fut is fut or (self._read_fut is None and
self._closing)
self._read_fut = None
data = fut.result() # deliver data later in "finally" clause
if self._closing:
# since close() has been called we ignore any read data
data = None
return
if data == b'':
# we got end-of-file so no need to reschedule a new read
return
# reschedule a new read
self._read_fut = self._loop._proactor.recv(self._sock, 4096)
except ConnectionAbortedError as exc:
if not self._closing:
self._fatal_error(exc)
except ConnectionResetError as exc:
self._force_close(exc)
except OSError as exc:
self._fatal_error(exc)
except futures.CancelledError:
if not self._closing:
raise
else:
self._read_fut.add_done_callback(self._loop_reading)
finally:
if data:
self._protocol.data_received(data)
elif data is not None:
keep_open = self._protocol.eof_received()
if not keep_open:
self.close()
class _ProactorWritePipeTransport(_ProactorBasePipeTransport,
transports.WriteTransport):
"""Transport for write pipes."""
def write(self, data):
assert isinstance(data, bytes), repr(data)
if self._eof_written:
raise IOError('write_eof() already called')
if not data:
return
if self._conn_lost:
if self._conn_lost >= constants.LOG_THRESHOLD_FOR_CONNLOST_WRITES:
logger.warning('socket.send() raised exception.')
self._conn_lost += 1
return
self._buffer.append(data)
if self._write_fut is None:
self._loop_writing()
def _loop_writing(self, f=None):
try:
assert f is self._write_fut
self._write_fut = None
if f:
f.result()
data = b''.join(self._buffer)
self._buffer = []
if not data:
if self._closing:
self._loop.call_soon(self._call_connection_lost, None)
if self._eof_written:
self._sock.shutdown(socket.SHUT_WR)
return
self._write_fut = self._loop._proactor.send(self._sock, data)
self._write_fut.add_done_callback(self._loop_writing)
except ConnectionResetError as exc:
self._force_close(exc)
except OSError as exc:
self._fatal_error(exc)
def can_write_eof(self):
return True
def write_eof(self):
self.close()
def abort(self):
self._force_close(None)
class _ProactorDuplexPipeTransport(_ProactorReadPipeTransport,
_ProactorWritePipeTransport,
transports.Transport):
"""Transport for duplex pipes."""
def can_write_eof(self):
return False
def write_eof(self):
raise NotImplementedError
class _ProactorSocketTransport(_ProactorReadPipeTransport,
_ProactorWritePipeTransport,
transports.Transport):
"""Transport for connected sockets."""
def _set_extra(self, sock):
self._extra['socket'] = sock
try:
self._extra['sockname'] = sock.getsockname()
except (socket.error, AttributeError):
pass
if 'peername' not in self._extra:
try:
self._extra['peername'] = sock.getpeername()
except (socket.error, AttributeError):
pass
def can_write_eof(self):
return True
def write_eof(self):
if self._closing or self._eof_written:
return
self._eof_written = True
if self._write_fut is None:
self._sock.shutdown(socket.SHUT_WR)
class BaseProactorEventLoop(base_events.BaseEventLoop):
def __init__(self, proactor):
super().__init__()
logger.debug('Using proactor: %s', proactor.__class__.__name__)
self._proactor = proactor
self._selector = proactor # convenient alias
proactor.set_loop(self)
self._make_self_pipe()
def _make_socket_transport(self, sock, protocol, waiter=None,
extra=None, server=None):
return _ProactorSocketTransport(self, sock, protocol, waiter,
extra, server)
def _make_duplex_pipe_transport(self, sock, protocol, waiter=None,
extra=None):
return _ProactorDuplexPipeTransport(self,
sock, protocol, waiter, extra)
def _make_read_pipe_transport(self, sock, protocol, waiter=None,
extra=None):
return _ProactorReadPipeTransport(self, sock, protocol, waiter, extra)
def _make_write_pipe_transport(self, sock, protocol, waiter=None,
extra=None):
return _ProactorWritePipeTransport(self, sock, protocol, waiter, extra)
def close(self):
if self._proactor is not None:
self._close_self_pipe()
self._proactor.close()
self._proactor = None
self._selector = None
super().close()
def sock_recv(self, sock, n):
return self._proactor.recv(sock, n)
def sock_sendall(self, sock, data):
return self._proactor.send(sock, data)
def sock_connect(self, sock, address):
return self._proactor.connect(sock, address)
def sock_accept(self, sock):
return self._proactor.accept(sock)
def _socketpair(self):
raise NotImplementedError
def _close_self_pipe(self):
self._ssock.close()
self._ssock = None
self._csock.close()
self._csock = None
self._internal_fds -= 1
def _make_self_pipe(self):
# A self-socket, really. :-)
self._ssock, self._csock = self._socketpair()
self._ssock.setblocking(False)
self._csock.setblocking(False)
self._internal_fds += 1
self.call_soon(self._loop_self_reading)
def _loop_self_reading(self, f=None):
try:
if f is not None:
f.result() # may raise
f = self._proactor.recv(self._ssock, 4096)
except:
self.close()
raise
else:
f.add_done_callback(self._loop_self_reading)
def _write_to_self(self):
self._csock.send(b'x')
def _start_serving(self, protocol_factory, sock, ssl=None, server=None):
assert not ssl, 'IocpEventLoop is incompatible with SSL.'
def loop(f=None):
try:
if f is not None:
conn, addr = f.result()
protocol = protocol_factory()
self._make_socket_transport(
conn, protocol,
extra={'peername': addr}, server=server)
f = self._proactor.accept(sock)
except OSError:
if sock.fileno() != -1:
logger.exception('Accept failed')
sock.close()
except futures.CancelledError:
sock.close()
else:
f.add_done_callback(loop)
self.call_soon(loop)
def _process_events(self, event_list):
pass # XXX hard work currently done in poll
def _stop_serving(self, sock):
self._proactor._stop_serving(sock)
sock.close()