456 lines
16 KiB
Python
456 lines
16 KiB
Python
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"""Event loop using a proactor and related classes.
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A proactor is a "notify-on-completion" multiplexer. Currently a
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proactor is only implemented on Windows with IOCP.
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"""
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__all__ = ['BaseProactorEventLoop']
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import socket
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from . import base_events
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from . import constants
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from . import futures
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from . import transports
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from .log import logger
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class _ProactorBasePipeTransport(transports._FlowControlMixin,
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transports.BaseTransport):
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"""Base class for pipe and socket transports."""
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def __init__(self, loop, sock, protocol, waiter=None,
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extra=None, server=None):
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super().__init__(extra)
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self._set_extra(sock)
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self._loop = loop
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self._sock = sock
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self._protocol = protocol
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self._server = server
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self._buffer = None # None or bytearray.
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self._read_fut = None
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self._write_fut = None
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self._pending_write = 0
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self._conn_lost = 0
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self._closing = False # Set when close() called.
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self._eof_written = False
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if self._server is not None:
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self._server.attach(self)
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self._loop.call_soon(self._protocol.connection_made, self)
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if waiter is not None:
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self._loop.call_soon(waiter.set_result, None)
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def _set_extra(self, sock):
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self._extra['pipe'] = sock
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def close(self):
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if self._closing:
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return
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self._closing = True
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self._conn_lost += 1
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if not self._buffer and self._write_fut is None:
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self._loop.call_soon(self._call_connection_lost, None)
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if self._read_fut is not None:
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self._read_fut.cancel()
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def _fatal_error(self, exc, message='Fatal error on pipe transport'):
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if not isinstance(exc, (BrokenPipeError, ConnectionResetError)):
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self._loop.call_exception_handler({
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'message': message,
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'exception': exc,
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'transport': self,
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'protocol': self._protocol,
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})
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self._force_close(exc)
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def _force_close(self, exc):
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if self._closing:
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return
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self._closing = True
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self._conn_lost += 1
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if self._write_fut:
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self._write_fut.cancel()
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if self._read_fut:
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self._read_fut.cancel()
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self._write_fut = self._read_fut = None
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self._pending_write = 0
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self._buffer = None
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self._loop.call_soon(self._call_connection_lost, exc)
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def _call_connection_lost(self, exc):
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try:
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self._protocol.connection_lost(exc)
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finally:
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# XXX If there is a pending overlapped read on the other
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# end then it may fail with ERROR_NETNAME_DELETED if we
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# just close our end. First calling shutdown() seems to
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# cure it, but maybe using DisconnectEx() would be better.
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if hasattr(self._sock, 'shutdown'):
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self._sock.shutdown(socket.SHUT_RDWR)
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self._sock.close()
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server = self._server
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if server is not None:
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server.detach(self)
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self._server = None
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def get_write_buffer_size(self):
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size = self._pending_write
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if self._buffer is not None:
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size += len(self._buffer)
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return size
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class _ProactorReadPipeTransport(_ProactorBasePipeTransport,
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transports.ReadTransport):
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"""Transport for read pipes."""
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def __init__(self, loop, sock, protocol, waiter=None,
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extra=None, server=None):
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super().__init__(loop, sock, protocol, waiter, extra, server)
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self._read_fut = None
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self._paused = False
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self._loop.call_soon(self._loop_reading)
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def pause_reading(self):
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if self._closing:
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raise RuntimeError('Cannot pause_reading() when closing')
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if self._paused:
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raise RuntimeError('Already paused')
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self._paused = True
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def resume_reading(self):
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if not self._paused:
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raise RuntimeError('Not paused')
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self._paused = False
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if self._closing:
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return
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self._loop.call_soon(self._loop_reading, self._read_fut)
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def _loop_reading(self, fut=None):
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if self._paused:
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return
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data = None
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try:
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if fut is not None:
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assert self._read_fut is fut or (self._read_fut is None and
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self._closing)
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self._read_fut = None
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data = fut.result() # deliver data later in "finally" clause
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if self._closing:
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# since close() has been called we ignore any read data
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data = None
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return
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if data == b'':
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# we got end-of-file so no need to reschedule a new read
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return
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# reschedule a new read
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self._read_fut = self._loop._proactor.recv(self._sock, 4096)
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except ConnectionAbortedError as exc:
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if not self._closing:
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self._fatal_error(exc, 'Fatal read error on pipe transport')
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except ConnectionResetError as exc:
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self._force_close(exc)
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except OSError as exc:
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self._fatal_error(exc, 'Fatal read error on pipe transport')
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except futures.CancelledError:
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if not self._closing:
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raise
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else:
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self._read_fut.add_done_callback(self._loop_reading)
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finally:
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if data:
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self._protocol.data_received(data)
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elif data is not None:
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keep_open = self._protocol.eof_received()
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if not keep_open:
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self.close()
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class _ProactorBaseWritePipeTransport(_ProactorBasePipeTransport,
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transports.WriteTransport):
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"""Transport for write pipes."""
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def write(self, data):
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if not isinstance(data, (bytes, bytearray, memoryview)):
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raise TypeError('data argument must be byte-ish (%r)',
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type(data))
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if self._eof_written:
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raise RuntimeError('write_eof() already called')
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if not data:
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return
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if self._conn_lost:
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if self._conn_lost >= constants.LOG_THRESHOLD_FOR_CONNLOST_WRITES:
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logger.warning('socket.send() raised exception.')
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self._conn_lost += 1
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return
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# Observable states:
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# 1. IDLE: _write_fut and _buffer both None
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# 2. WRITING: _write_fut set; _buffer None
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# 3. BACKED UP: _write_fut set; _buffer a bytearray
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# We always copy the data, so the caller can't modify it
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# while we're still waiting for the I/O to happen.
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if self._write_fut is None: # IDLE -> WRITING
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assert self._buffer is None
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# Pass a copy, except if it's already immutable.
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self._loop_writing(data=bytes(data))
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# XXX Should we pause the protocol at this point
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# if len(data) > self._high_water? (That would
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# require keeping track of the number of bytes passed
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# to a send() that hasn't finished yet.)
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elif not self._buffer: # WRITING -> BACKED UP
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# Make a mutable copy which we can extend.
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self._buffer = bytearray(data)
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self._maybe_pause_protocol()
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else: # BACKED UP
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# Append to buffer (also copies).
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self._buffer.extend(data)
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self._maybe_pause_protocol()
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def _loop_writing(self, f=None, data=None):
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try:
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assert f is self._write_fut
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self._write_fut = None
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self._pending_write = 0
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if f:
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f.result()
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if data is None:
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data = self._buffer
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self._buffer = None
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if not data:
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if self._closing:
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self._loop.call_soon(self._call_connection_lost, None)
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if self._eof_written:
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self._sock.shutdown(socket.SHUT_WR)
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# Now that we've reduced the buffer size, tell the
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# protocol to resume writing if it was paused. Note that
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# we do this last since the callback is called immediately
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# and it may add more data to the buffer (even causing the
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# protocol to be paused again).
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self._maybe_resume_protocol()
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else:
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self._write_fut = self._loop._proactor.send(self._sock, data)
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if not self._write_fut.done():
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assert self._pending_write == 0
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self._pending_write = len(data)
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self._write_fut.add_done_callback(self._loop_writing)
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self._maybe_pause_protocol()
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else:
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self._write_fut.add_done_callback(self._loop_writing)
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except ConnectionResetError as exc:
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self._force_close(exc)
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except OSError as exc:
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self._fatal_error(exc, 'Fatal write error on pipe transport')
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def can_write_eof(self):
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return True
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def write_eof(self):
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self.close()
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def abort(self):
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self._force_close(None)
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class _ProactorWritePipeTransport(_ProactorBaseWritePipeTransport):
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def __init__(self, *args, **kw):
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super().__init__(*args, **kw)
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self._read_fut = self._loop._proactor.recv(self._sock, 16)
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self._read_fut.add_done_callback(self._pipe_closed)
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def _pipe_closed(self, fut):
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if fut.cancelled():
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# the transport has been closed
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return
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assert fut.result() == b''
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if self._closing:
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assert self._read_fut is None
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return
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assert fut is self._read_fut, (fut, self._read_fut)
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self._read_fut = None
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if self._write_fut is not None:
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self._force_close(BrokenPipeError())
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else:
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self.close()
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class _ProactorDuplexPipeTransport(_ProactorReadPipeTransport,
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_ProactorBaseWritePipeTransport,
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transports.Transport):
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"""Transport for duplex pipes."""
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def can_write_eof(self):
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return False
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def write_eof(self):
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raise NotImplementedError
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class _ProactorSocketTransport(_ProactorReadPipeTransport,
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_ProactorBaseWritePipeTransport,
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transports.Transport):
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"""Transport for connected sockets."""
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def _set_extra(self, sock):
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self._extra['socket'] = sock
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try:
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self._extra['sockname'] = sock.getsockname()
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except (socket.error, AttributeError):
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pass
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if 'peername' not in self._extra:
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try:
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self._extra['peername'] = sock.getpeername()
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except (socket.error, AttributeError):
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pass
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def can_write_eof(self):
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return True
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def write_eof(self):
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if self._closing or self._eof_written:
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return
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self._eof_written = True
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if self._write_fut is None:
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self._sock.shutdown(socket.SHUT_WR)
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class BaseProactorEventLoop(base_events.BaseEventLoop):
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def __init__(self, proactor):
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super().__init__()
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logger.debug('Using proactor: %s', proactor.__class__.__name__)
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self._proactor = proactor
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self._selector = proactor # convenient alias
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self._self_reading_future = None
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self._accept_futures = {} # socket file descriptor => Future
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proactor.set_loop(self)
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self._make_self_pipe()
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def _make_socket_transport(self, sock, protocol, waiter=None,
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extra=None, server=None):
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return _ProactorSocketTransport(self, sock, protocol, waiter,
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extra, server)
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def _make_duplex_pipe_transport(self, sock, protocol, waiter=None,
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extra=None):
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return _ProactorDuplexPipeTransport(self,
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sock, protocol, waiter, extra)
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def _make_read_pipe_transport(self, sock, protocol, waiter=None,
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extra=None):
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return _ProactorReadPipeTransport(self, sock, protocol, waiter, extra)
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def _make_write_pipe_transport(self, sock, protocol, waiter=None,
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extra=None):
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# We want connection_lost() to be called when other end closes
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return _ProactorWritePipeTransport(self,
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sock, protocol, waiter, extra)
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def close(self):
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if self._proactor is not None:
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self._close_self_pipe()
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self._proactor.close()
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self._proactor = None
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self._selector = None
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super().close()
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self._accept_futures.clear()
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def sock_recv(self, sock, n):
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return self._proactor.recv(sock, n)
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def sock_sendall(self, sock, data):
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return self._proactor.send(sock, data)
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def sock_connect(self, sock, address):
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try:
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base_events._check_resolved_address(sock, address)
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except ValueError as err:
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fut = futures.Future(loop=self)
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fut.set_exception(err)
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return fut
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else:
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return self._proactor.connect(sock, address)
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def sock_accept(self, sock):
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return self._proactor.accept(sock)
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def _socketpair(self):
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raise NotImplementedError
|
||
|
|
|
||
|
|
def _close_self_pipe(self):
|
||
|
|
if self._self_reading_future is not None:
|
||
|
|
self._self_reading_future.cancel()
|
||
|
|
self._self_reading_future = None
|
||
|
|
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:
|
||
|
|
self._self_reading_future = f
|
||
|
|
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):
|
||
|
|
if ssl:
|
||
|
|
raise ValueError('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 as exc:
|
||
|
|
if sock.fileno() != -1:
|
||
|
|
self.call_exception_handler({
|
||
|
|
'message': 'Accept failed',
|
||
|
|
'exception': exc,
|
||
|
|
'socket': sock,
|
||
|
|
})
|
||
|
|
sock.close()
|
||
|
|
except futures.CancelledError:
|
||
|
|
sock.close()
|
||
|
|
else:
|
||
|
|
self._accept_futures[sock.fileno()] = f
|
||
|
|
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):
|
||
|
|
for future in self._accept_futures.values():
|
||
|
|
future.cancel()
|
||
|
|
self._proactor._stop_serving(sock)
|
||
|
|
sock.close()
|