peer_tcp_client.py 文件源码

def _handle_requests(self, message_id: MessageType, payload: memoryview):
        piece_index, begin, length = struct.unpack('!3I', cast(bytes, payload))
        request = BlockRequest(piece_index, begin, length)
        self._check_position_range(request)

        if message_id == MessageType.request:
            if length > PeerTCPClient.MAX_REQUEST_LENGTH:
                raise ValueError('Requested {} bytes, but the current policy allows to accept requests '
                                 'of not more than {} bytes'.format(length, PeerTCPClient.MAX_REQUEST_LENGTH))
            if (self._am_choking or not self._peer_interested or
                    not self._download_info.pieces[piece_index].downloaded):
                # If peer isn't interested but requesting, their peer_interested flag wasn't considered
                # when selecting who to unchoke, so we may be not ready to upload to them.
                # If requested piece is not downloaded yet, we shouldn't disconnect because our piece_downloaded flag
                # could be removed because of file corruption.
                return

            await self._send_block(request)
            await self.drain()
        elif message_id == MessageType.cancel:
            # Now we answer to a request immediately or reject and forget it,
            # so there's no need to handle cancel messages
            pass