whisper: add MsgReadWriter interface to libp2p net.Stream

whisper/whisperv6/libp2p_glue.go

@@ -0,0 +1,93 @@
+// Copyright 2018 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package whisperv6
+
+import (
+	"bytes"
+	"encoding/binary"
+	"fmt"
+
+	"github.com/ethereum/go-ethereum/p2p"
+	inet "github.com/libp2p/go-libp2p-net"
+)
+
+type LibP2PStream struct {
+	stream inet.Stream
+}
+
+const (
+	codeLength        = 8
+	payloadSizeLength = 4
+)
+
+// ReadMsg implements the MsgReadWriter interface to read messages
+// from lilbp2p streams.
+func (stream *LibP2PStream) ReadMsg() (p2p.Msg, error) {
+	codeBytes := make([]byte, codeLength)
+	nbytes, err := stream.stream.Read(codeBytes)
+	if err != nil {
+		return p2p.Msg{}, err
+	} else if nbytes != len(codeBytes) {
+		return p2p.Msg{}, fmt.Errorf("Invalid message header length: expected %d, got %d", codeLength, nbytes)
+	}
+	code := binary.LittleEndian.Uint64(codeBytes)
+
+	sizeBytes := make([]byte, payloadSizeLength)
+	nbytes, err = stream.stream.Read(sizeBytes)
+	if err != nil {
+		return p2p.Msg{}, err
+	} else if nbytes != len(sizeBytes) {
+		return p2p.Msg{}, fmt.Errorf("Invalid message size length: expected %d, got %d", len(sizeBytes), nbytes)
+	}
+	size := binary.LittleEndian.Uint32(sizeBytes)
+
+	payload := make([]byte, size)
+	nbytes, err = stream.stream.Read(payload)
+	if err != nil {
+		return p2p.Msg{}, err
+	} else if nbytes != int(size) {
+		return p2p.Msg{}, fmt.Errorf("Invalid message payload length: expected %d, got %d", size, nbytes)
+	}
+
+	return p2p.Msg{Code: code, Size: size, Payload: bytes.NewReader(payload)}, nil
+}
+
+// WriteMsg implements the MsgReadWriter interface to write messages
+// to lilbp2p streams.
+func (stream *LibP2PStream) WriteMsg(msg p2p.Msg) error {
+	data := make([]byte, msg.Size+codeLength+payloadSizeLength)
+
+	binary.LittleEndian.PutUint64(data[0:codeLength], msg.Code)
+	binary.LittleEndian.PutUint32(data[codeLength:codeLength+payloadSizeLength], msg.Size)
+
+	nbytes, err := msg.Payload.Read(data[8:])
+	if (nbytes&0xFFFFFFFF) != nbytes || uint32(nbytes) != msg.Size {
+		return fmt.Errorf("Invalid size read in libp2p stream: read %d bytes, was expecting %d bytes", nbytes, msg.Size)
+	}
+
+	nbytes, err = stream.stream.Write(data)
+
+	if err != nil {
+		return err
+	}
+
+	if nbytes != len(data) {
+		return fmt.Errorf("Invalid size written in libp2p stream: wrote %d bytes, was expecting %d bytes", nbytes, msg.Size)
+	}
+
+	return nil
+}