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proactor_events.py31.4 KB · 870 lines
"""Event loop using a proactor and related classes. A proactor is a "notify-on-completion" multiplexer.  Currently aproactor is only implemented on Windows with IOCP.""" __all__ = 'BaseProactorEventLoop', import ioimport osimport socketimport warningsimport signalimport threadingimport collections from . import base_eventsfrom . import constantsfrom . import futuresfrom . import exceptionsfrom . import protocolsfrom . import sslprotofrom . import transportsfrom . import trsockfrom .log import logger  def _set_socket_extra(transport, sock):    transport._extra['socket'] = trsock.TransportSocket(sock)     try:        transport._extra['sockname'] = sock.getsockname()    except socket.error:        if transport._loop.get_debug():            logger.warning(                "getsockname() failed on %r", sock, exc_info=True)     if 'peername' not in transport._extra:        try:            transport._extra['peername'] = sock.getpeername()        except socket.error:            # UDP sockets may not have a peer name            transport._extra['peername'] = None  class _ProactorBasePipeTransport(transports._FlowControlMixin,                                 transports.BaseTransport):    """Base class for pipe and socket transports."""     def __init__(self, loop, sock, protocol, waiter=None,                 extra=None, server=None):        super().__init__(extra, loop)        self._set_extra(sock)        self._sock = sock        self.set_protocol(protocol)        self._server = server        self._buffer = None  # None or bytearray.        self._read_fut = None        self._write_fut = None        self._pending_write = 0        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._loop.call_soon(self._protocol.connection_made, self)        if waiter is not None:            # only wake up the waiter when connection_made() has been called            self._loop.call_soon(futures._set_result_unless_cancelled,                                 waiter, None)     def __repr__(self):        info = [self.__class__.__name__]        if self._sock is None:            info.append('closed')        elif self._closing:            info.append('closing')        if self._sock is not None:            info.append(f'fd={self._sock.fileno()}')        if self._read_fut is not None:            info.append(f'read={self._read_fut!r}')        if self._write_fut is not None:            info.append(f'write={self._write_fut!r}')        if self._buffer:            info.append(f'write_bufsize={len(self._buffer)}')        if self._eof_written:            info.append('EOF written')        return '<{}>'.format(' '.join(info))     def _set_extra(self, sock):        self._extra['pipe'] = sock     def set_protocol(self, protocol):        self._protocol = protocol     def get_protocol(self):        return self._protocol     def is_closing(self):        return self._closing     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()            self._read_fut = None     def __del__(self, _warn=warnings.warn):        if self._sock is not None:            _warn(f"unclosed transport {self!r}", ResourceWarning, source=self)            self.close()     def _fatal_error(self, exc, message='Fatal error on pipe transport'):        try:            if isinstance(exc, OSError):                if self._loop.get_debug():                    logger.debug("%r: %s", self, message, exc_info=True)            else:                self._loop.call_exception_handler({                    'message': message,                    'exception': exc,                    'transport': self,                    'protocol': self._protocol,                })        finally:            self._force_close(exc)     def _force_close(self, exc):        if self._empty_waiter is not None and not self._empty_waiter.done():            if exc is None:                self._empty_waiter.set_result(None)            else:                self._empty_waiter.set_exception(exc)        if self._closing:            return        self._closing = True        self._conn_lost += 1        if self._write_fut:            self._write_fut.cancel()            self._write_fut = None        if self._read_fut:            self._read_fut.cancel()            self._read_fut = None        self._pending_write = 0        self._buffer = None        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') and self._sock.fileno() != -1:                self._sock.shutdown(socket.SHUT_RDWR)            self._sock.close()            self._sock = None            server = self._server            if server is not None:                server._detach()                self._server = None     def get_write_buffer_size(self):        size = self._pending_write        if self._buffer is not None:            size += len(self._buffer)        return size  class _ProactorReadPipeTransport(_ProactorBasePipeTransport,                                 transports.ReadTransport):    """Transport for read pipes."""     def __init__(self, loop, sock, protocol, waiter=None,                 extra=None, server=None):        self._pending_data = None        self._paused = True        super().__init__(loop, sock, protocol, waiter, extra, server)         self._loop.call_soon(self._loop_reading)        self._paused = False     def is_reading(self):        return not self._paused and not self._closing     def pause_reading(self):        if self._closing or self._paused:            return        self._paused = True         # bpo-33694: Don't cancel self._read_fut because cancelling an        # overlapped WSASend() loss silently data with the current proactor        # implementation.        #        # If CancelIoEx() fails with ERROR_NOT_FOUND, it means that WSASend()        # completed (even if HasOverlappedIoCompleted() returns 0), but        # Overlapped.cancel() currently silently ignores the ERROR_NOT_FOUND        # error. Once the overlapped is ignored, the IOCP loop will ignores the        # completion I/O event and so not read the result of the overlapped        # WSARecv().         if self._loop.get_debug():            logger.debug("%r pauses reading", self)     def resume_reading(self):        if self._closing or not self._paused:            return         self._paused = False        if self._read_fut is None:            self._loop.call_soon(self._loop_reading, None)         data = self._pending_data        self._pending_data = None        if data is not None:            # Call the protocol methode after calling _loop_reading(),            # since the protocol can decide to pause reading again.            self._loop.call_soon(self._data_received, data)         if self._loop.get_debug():            logger.debug("%r resumes reading", self)     def _eof_received(self):        if self._loop.get_debug():            logger.debug("%r received EOF", self)         try:            keep_open = self._protocol.eof_received()        except (SystemExit, KeyboardInterrupt):            raise        except BaseException as exc:            self._fatal_error(                exc, 'Fatal error: protocol.eof_received() call failed.')            return         if not keep_open:            self.close()     def _data_received(self, data):        if self._paused:            # Don't call any protocol method while reading is paused.            # The protocol will be called on resume_reading().            assert self._pending_data is None            self._pending_data = data            return         if not data:            self._eof_received()            return         if isinstance(self._protocol, protocols.BufferedProtocol):            try:                protocols._feed_data_to_buffered_proto(self._protocol, data)            except (SystemExit, KeyboardInterrupt):                raise            except BaseException as exc:                self._fatal_error(exc,                                  'Fatal error: protocol.buffer_updated() '                                  'call failed.')                return        else:            self._protocol.data_received(data)     def _loop_reading(self, fut=None):        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                if fut.done():                    # deliver data later in "finally" clause                    data = fut.result()                else:                    # the future will be replaced by next proactor.recv call                    fut.cancel()             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             # bpo-33694: buffer_updated() has currently no fast path because of            # a data loss issue caused by overlapped WSASend() cancellation.             if not self._paused:                # reschedule a new read                self._read_fut = self._loop._proactor.recv(self._sock, 32768)        except ConnectionAbortedError as exc:            if not self._closing:                self._fatal_error(exc, 'Fatal read error on pipe transport')            elif self._loop.get_debug():                logger.debug("Read error on pipe transport while closing",                             exc_info=True)        except ConnectionResetError as exc:            self._force_close(exc)        except OSError as exc:            self._fatal_error(exc, 'Fatal read error on pipe transport')        except exceptions.CancelledError:            if not self._closing:                raise        else:            if not self._paused:                self._read_fut.add_done_callback(self._loop_reading)        finally:            if data is not None:                self._data_received(data)  class _ProactorBaseWritePipeTransport(_ProactorBasePipeTransport,                                      transports.WriteTransport):    """Transport for write pipes."""     _start_tls_compatible = True     def __init__(self, *args, **kw):        super().__init__(*args, **kw)        self._empty_waiter = None     def write(self, data):        if not isinstance(data, (bytes, bytearray, memoryview)):            raise TypeError(                f"data argument must be a bytes-like object, "                f"not {type(data).__name__}")        if self._eof_written:            raise RuntimeError('write_eof() already called')        if self._empty_waiter is not None:            raise RuntimeError('unable to write; sendfile is in progress')         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         # Observable states:        # 1. IDLE: _write_fut and _buffer both None        # 2. WRITING: _write_fut set; _buffer None        # 3. BACKED UP: _write_fut set; _buffer a bytearray        # We always copy the data, so the caller can't modify it        # while we're still waiting for the I/O to happen.        if self._write_fut is None:  # IDLE -> WRITING            assert self._buffer is None            # Pass a copy, except if it's already immutable.            self._loop_writing(data=bytes(data))        elif not self._buffer:  # WRITING -> BACKED UP            # Make a mutable copy which we can extend.            self._buffer = bytearray(data)            self._maybe_pause_protocol()        else:  # BACKED UP            # Append to buffer (also copies).            self._buffer.extend(data)            self._maybe_pause_protocol()     def _loop_writing(self, f=None, data=None):        try:            if f is not None and self._write_fut is None and self._closing:                # XXX most likely self._force_close() has been called, and                # it has set self._write_fut to None.                return            assert f is self._write_fut            self._write_fut = None            self._pending_write = 0            if f:                f.result()            if data is None:                data = self._buffer                self._buffer = None            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)                # Now that we've reduced the buffer size, tell the                # protocol to resume writing if it was paused.  Note that                # we do this last since the callback is called immediately                # and it may add more data to the buffer (even causing the                # protocol to be paused again).                self._maybe_resume_protocol()            else:                self._write_fut = self._loop._proactor.send(self._sock, data)                if not self._write_fut.done():                    assert self._pending_write == 0                    self._pending_write = len(data)                    self._write_fut.add_done_callback(self._loop_writing)                    self._maybe_pause_protocol()                else:                    self._write_fut.add_done_callback(self._loop_writing)            if self._empty_waiter is not None and self._write_fut is None:                self._empty_waiter.set_result(None)        except ConnectionResetError as exc:            self._force_close(exc)        except OSError as exc:            self._fatal_error(exc, 'Fatal write error on pipe transport')     def can_write_eof(self):        return True     def write_eof(self):        self.close()     def abort(self):        self._force_close(None)     def _make_empty_waiter(self):        if self._empty_waiter is not None:            raise RuntimeError("Empty waiter is already set")        self._empty_waiter = self._loop.create_future()        if self._write_fut is None:            self._empty_waiter.set_result(None)        return self._empty_waiter     def _reset_empty_waiter(self):        self._empty_waiter = None  class _ProactorWritePipeTransport(_ProactorBaseWritePipeTransport):    def __init__(self, *args, **kw):        super().__init__(*args, **kw)        self._read_fut = self._loop._proactor.recv(self._sock, 16)        self._read_fut.add_done_callback(self._pipe_closed)     def _pipe_closed(self, fut):        if fut.cancelled():            # the transport has been closed            return        assert fut.result() == b''        if self._closing:            assert self._read_fut is None            return        assert fut is self._read_fut, (fut, self._read_fut)        self._read_fut = None        if self._write_fut is not None:            self._force_close(BrokenPipeError())        else:            self.close()  class _ProactorDatagramTransport(_ProactorBasePipeTransport,                                 transports.DatagramTransport):    max_size = 256 * 1024    def __init__(self, loop, sock, protocol, address=None,                 waiter=None, extra=None):        self._address = address        self._empty_waiter = None        # We don't need to call _protocol.connection_made() since our base        # constructor does it for us.        super().__init__(loop, sock, protocol, waiter=waiter, extra=extra)         # The base constructor sets _buffer = None, so we set it here        self._buffer = collections.deque()        self._loop.call_soon(self._loop_reading)     def _set_extra(self, sock):        _set_socket_extra(self, sock)     def get_write_buffer_size(self):        return sum(len(data) for data, _ in self._buffer)     def abort(self):        self._force_close(None)     def sendto(self, data, addr=None):        if not isinstance(data, (bytes, bytearray, memoryview)):            raise TypeError('data argument must be bytes-like object (%r)',                            type(data))         if not data:            return         if self._address is not None and addr not in (None, self._address):            raise ValueError(                f'Invalid address: must be None or {self._address}')         if self._conn_lost and self._address:            if self._conn_lost >= constants.LOG_THRESHOLD_FOR_CONNLOST_WRITES:                logger.warning('socket.sendto() raised exception.')            self._conn_lost += 1            return         # Ensure that what we buffer is immutable.        self._buffer.append((bytes(data), addr))         if self._write_fut is None:            # No current write operations are active, kick one off            self._loop_writing()        # else: A write operation is already kicked off         self._maybe_pause_protocol()     def _loop_writing(self, fut=None):        try:            if self._conn_lost:                return             assert fut is self._write_fut            self._write_fut = None            if fut:                # We are in a _loop_writing() done callback, get the result                fut.result()             if not self._buffer or (self._conn_lost and self._address):                # The connection has been closed                if self._closing:                    self._loop.call_soon(self._call_connection_lost, None)                return             data, addr = self._buffer.popleft()            if self._address is not None:                self._write_fut = self._loop._proactor.send(self._sock,                                                            data)            else:                self._write_fut = self._loop._proactor.sendto(self._sock,                                                              data,                                                              addr=addr)        except OSError as exc:            self._protocol.error_received(exc)        except Exception as exc:            self._fatal_error(exc, 'Fatal write error on datagram transport')        else:            self._write_fut.add_done_callback(self._loop_writing)            self._maybe_resume_protocol()     def _loop_reading(self, fut=None):        data = None        try:            if self._conn_lost:                return             assert self._read_fut is fut or (self._read_fut is None and                                             self._closing)             self._read_fut = None            if fut is not None:                res = fut.result()                 if self._closing:                    # since close() has been called we ignore any read data                    data = None                    return                 if self._address is not None:                    data, addr = res, self._address                else:                    data, addr = res             if self._conn_lost:                return            if self._address is not None:                self._read_fut = self._loop._proactor.recv(self._sock,                                                           self.max_size)            else:                self._read_fut = self._loop._proactor.recvfrom(self._sock,                                                               self.max_size)        except OSError as exc:            self._protocol.error_received(exc)        except exceptions.CancelledError:            if not self._closing:                raise        else:            if self._read_fut is not None:                self._read_fut.add_done_callback(self._loop_reading)        finally:            if data:                self._protocol.datagram_received(data, addr)  class _ProactorDuplexPipeTransport(_ProactorReadPipeTransport,                                   _ProactorBaseWritePipeTransport,                                   transports.Transport):    """Transport for duplex pipes."""     def can_write_eof(self):        return False     def write_eof(self):        raise NotImplementedError  class _ProactorSocketTransport(_ProactorReadPipeTransport,                               _ProactorBaseWritePipeTransport,                               transports.Transport):    """Transport for connected sockets."""     _sendfile_compatible = constants._SendfileMode.TRY_NATIVE     def __init__(self, loop, sock, protocol, waiter=None,                 extra=None, server=None):        super().__init__(loop, sock, protocol, waiter, extra, server)        base_events._set_nodelay(sock)     def _set_extra(self, sock):        _set_socket_extra(self, sock)     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        self._self_reading_future = None        self._accept_futures = {}   # socket file descriptor => Future        proactor.set_loop(self)        self._make_self_pipe()        if threading.current_thread() is threading.main_thread():            # wakeup fd can only be installed to a file descriptor from the main thread            signal.set_wakeup_fd(self._csock.fileno())     def _make_socket_transport(self, sock, protocol, waiter=None,                               extra=None, server=None):        return _ProactorSocketTransport(self, sock, protocol, waiter,                                        extra, server)     def _make_ssl_transport(            self, rawsock, protocol, sslcontext, waiter=None,            *, server_side=False, server_hostname=None,            extra=None, server=None,            ssl_handshake_timeout=None):        ssl_protocol = sslproto.SSLProtocol(                self, protocol, sslcontext, waiter,                server_side, server_hostname,                ssl_handshake_timeout=ssl_handshake_timeout)        _ProactorSocketTransport(self, rawsock, ssl_protocol,                                 extra=extra, server=server)        return ssl_protocol._app_transport     def _make_datagram_transport(self, sock, protocol,                                 address=None, waiter=None, extra=None):        return _ProactorDatagramTransport(self, sock, protocol, address,                                          waiter, extra)     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):        # We want connection_lost() to be called when other end closes        return _ProactorWritePipeTransport(self,                                           sock, protocol, waiter, extra)     def close(self):        if self.is_running():            raise RuntimeError("Cannot close a running event loop")        if self.is_closed():            return         if threading.current_thread() is threading.main_thread():            signal.set_wakeup_fd(-1)        # Call these methods before closing the event loop (before calling        # BaseEventLoop.close), because they can schedule callbacks with        # call_soon(), which is forbidden when the event loop is closed.        self._stop_accept_futures()        self._close_self_pipe()        self._proactor.close()        self._proactor = None        self._selector = None         # Close the event loop        super().close()     async def sock_recv(self, sock, n):        return await self._proactor.recv(sock, n)     async def sock_recv_into(self, sock, buf):        return await self._proactor.recv_into(sock, buf)     async def sock_sendall(self, sock, data):        return await self._proactor.send(sock, data)     async def sock_connect(self, sock, address):        return await self._proactor.connect(sock, address)     async def sock_accept(self, sock):        return await self._proactor.accept(sock)     async def _sock_sendfile_native(self, sock, file, offset, count):        try:            fileno = file.fileno()        except (AttributeError, io.UnsupportedOperation) as err:            raise exceptions.SendfileNotAvailableError("not a regular file")        try:            fsize = os.fstat(fileno).st_size        except OSError:            raise exceptions.SendfileNotAvailableError("not a regular file")        blocksize = count if count else fsize        if not blocksize:            return 0  # empty file         blocksize = min(blocksize, 0xffff_ffff)        end_pos = min(offset + count, fsize) if count else fsize        offset = min(offset, fsize)        total_sent = 0        try:            while True:                blocksize = min(end_pos - offset, blocksize)                if blocksize <= 0:                    return total_sent                await self._proactor.sendfile(sock, file, offset, blocksize)                offset += blocksize                total_sent += blocksize        finally:            if total_sent > 0:                file.seek(offset)     async def _sendfile_native(self, transp, file, offset, count):        resume_reading = transp.is_reading()        transp.pause_reading()        await transp._make_empty_waiter()        try:            return await self.sock_sendfile(transp._sock, file, offset, count,                                            fallback=False)        finally:            transp._reset_empty_waiter()            if resume_reading:                transp.resume_reading()     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 = socket.socketpair()        self._ssock.setblocking(False)        self._csock.setblocking(False)        self._internal_fds += 1     def _loop_self_reading(self, f=None):        try:            if f is not None:                f.result()  # may raise            if self._self_reading_future is not f:                # When we scheduled this Future, we assigned it to                # _self_reading_future. If it's not there now, something has                # tried to cancel the loop while this callback was still in the                # queue (see windows_events.ProactorEventLoop.run_forever). In                # that case stop here instead of continuing to schedule a new                # iteration.                return            f = self._proactor.recv(self._ssock, 4096)        except exceptions.CancelledError:            # _close_self_pipe() has been called, stop waiting for data            return        except (SystemExit, KeyboardInterrupt):            raise        except BaseException as exc:            self.call_exception_handler({                'message': 'Error on reading from the event loop self pipe',                'exception': exc,                'loop': self,            })        else:            self._self_reading_future = f            f.add_done_callback(self._loop_self_reading)     def _write_to_self(self):        # This may be called from a different thread, possibly after        # _close_self_pipe() has been called or even while it is        # running.  Guard for self._csock being None or closed.  When        # a socket is closed, send() raises OSError (with errno set to        # EBADF, but let's not rely on the exact error code).        csock = self._csock        if csock is None:            return         try:            csock.send(b'\0')        except OSError:            if self._debug:                logger.debug("Fail to write a null byte into the "                             "self-pipe socket",                             exc_info=True)     def _start_serving(self, protocol_factory, sock,                       sslcontext=None, server=None, backlog=100,                       ssl_handshake_timeout=None):         def loop(f=None):            try:                if f is not None:                    conn, addr = f.result()                    if self._debug:                        logger.debug("%r got a new connection from %r: %r",                                     server, addr, conn)                    protocol = protocol_factory()                    if sslcontext is not None:                        self._make_ssl_transport(                            conn, protocol, sslcontext, server_side=True,                            extra={'peername': addr}, server=server,                            ssl_handshake_timeout=ssl_handshake_timeout)                    else:                        self._make_socket_transport(                            conn, protocol,                            extra={'peername': addr}, server=server)                if self.is_closed():                    return                f = self._proactor.accept(sock)            except OSError as exc:                if sock.fileno() != -1:                    self.call_exception_handler({                        'message': 'Accept failed on a socket',                        'exception': exc,                        'socket': trsock.TransportSocket(sock),                    })                    sock.close()                elif self._debug:                    logger.debug("Accept failed on socket %r",                                 sock, exc_info=True)            except exceptions.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):        # Events are processed in the IocpProactor._poll() method        pass     def _stop_accept_futures(self):        for future in self._accept_futures.values():            future.cancel()        self._accept_futures.clear()     def _stop_serving(self, sock):        future = self._accept_futures.pop(sock.fileno(), None)        if future:            future.cancel()        self._proactor._stop_serving(sock)        sock.close()