Updated codec interface and code. Painful stuff

codec/proto/netstring.go

@@ -0,0 +1,36 @@
+package proto
+
+import (
+	"encoding/binary"
+	"io"
+)
+
+// WriteNetString writes data to a big-endian netstring on a Writer.
+// Size is always a 32-bit unsigned int.
+func WriteNetString(w io.Writer, data []byte) (written int, err error) {
+	size := make([]byte, 4)
+	binary.BigEndian.PutUint32(size, uint32(len(data)))
+	if written, err = w.Write(size); err != nil {
+		return
+	}
+	return w.Write(data)
+}
+
+// ReadNetString reads data from a big-endian netstring.
+func ReadNetString(r io.Reader) (data []byte, err error) {
+	sizeBuf := make([]byte, 4)
+	_, err = r.Read(sizeBuf)
+	if err != nil {
+		return nil, err
+	}
+	size := binary.BigEndian.Uint32(sizeBuf)
+	if size == 0 {
+		return nil, nil
+	}
+	data = make([]byte, size)
+	_, err = r.Read(data)
+	if err != nil {
+		return nil, err
+	}
+	return
+}

codec/proto/proto.go

@@ -0,0 +1,163 @@
+package proto
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"sync"
+
+	"github.com/golang/protobuf/proto"
+	"github.com/micro/go-micro/codec"
+	rpc "github.com/youtube/vitess/go/rpcplus/pbrpc"
+)
+
+type flusher interface {
+	Flush() error
+}
+
+type protoCodec struct {
+	sync.Mutex
+	rwc io.ReadWriteCloser
+	mt  codec.MessageType
+	buf *bytes.Buffer
+}
+
+func (c *protoCodec) Close() error {
+	c.buf.Reset()
+	return c.rwc.Close()
+}
+
+func (c *protoCodec) String() string {
+	return "proto"
+}
+
+func (c *protoCodec) Write(m *codec.Message, b interface{}) error {
+	switch m.Type {
+	case codec.Request:
+		c.Lock()
+		defer c.Unlock()
+		// This is protobuf, of course we copy it.
+		pbr := &rpc.Request{ServiceMethod: &m.Method, Seq: &m.Id}
+		data, err := proto.Marshal(pbr)
+		if err != nil {
+			return err
+		}
+		_, err = WriteNetString(c.rwc, data)
+		if err != nil {
+			return err
+		}
+		// Of course this is a protobuf! Trust me or detonate the program.
+		data, err = proto.Marshal(b.(proto.Message))
+		if err != nil {
+			return err
+		}
+		_, err = WriteNetString(c.rwc, data)
+		if err != nil {
+			return err
+		}
+		if flusher, ok := c.rwc.(flusher); ok {
+			err = flusher.Flush()
+		}
+	case codec.Response:
+		c.Lock()
+		defer c.Unlock()
+		rtmp := &rpc.Response{ServiceMethod: &m.Method, Seq: &m.Id, Error: &m.Error}
+		data, err := proto.Marshal(rtmp)
+		if err != nil {
+			return err
+		}
+		_, err = WriteNetString(c.rwc, data)
+		if err != nil {
+			return err
+		}
+		if pb, ok := b.(proto.Message); ok {
+			data, err = proto.Marshal(pb)
+			if err != nil {
+				return err
+			}
+		} else {
+			data = nil
+		}
+		_, err = WriteNetString(c.rwc, data)
+		if err != nil {
+			return err
+		}
+		if flusher, ok := c.rwc.(flusher); ok {
+			err = flusher.Flush()
+		}
+	case codec.Publication:
+		data, err := proto.Marshal(b.(proto.Message))
+		if err != nil {
+			return err
+		}
+		c.rwc.Write(data)
+	default:
+		return fmt.Errorf("Unrecognised message type: %v", m.Type)
+	}
+	return nil
+}
+
+func (c *protoCodec) ReadHeader(m *codec.Message, mt codec.MessageType) error {
+	c.buf.Reset()
+	c.mt = mt
+
+	switch mt {
+	case codec.Request:
+		data, err := ReadNetString(c.rwc)
+		if err != nil {
+			return err
+		}
+		rtmp := new(rpc.Request)
+		err = proto.Unmarshal(data, rtmp)
+		if err != nil {
+			return err
+		}
+		m.Method = *rtmp.ServiceMethod
+		m.Id = *rtmp.Seq
+	case codec.Response:
+		data, err := ReadNetString(c.rwc)
+		if err != nil {
+			return err
+		}
+		rtmp := new(rpc.Response)
+		err = proto.Unmarshal(data, rtmp)
+		if err != nil {
+			return err
+		}
+		m.Method = *rtmp.ServiceMethod
+		m.Id = *rtmp.Seq
+		m.Error = *rtmp.Error
+	case codec.Publication:
+		io.Copy(c.buf, c.rwc)
+	default:
+		return fmt.Errorf("Unrecognised message type: %v", mt)
+	}
+	return nil
+}
+
+func (c *protoCodec) ReadBody(b interface{}) error {
+	var data []byte
+	switch c.mt {
+	case codec.Request, codec.Response:
+		var err error
+		data, err = ReadNetString(c.rwc)
+		if err != nil {
+			return err
+		}
+	case codec.Publication:
+		data = c.buf.Bytes()
+	default:
+		return fmt.Errorf("Unrecognised message type: %v", c.mt)
+	}
+	if b != nil {
+		return proto.Unmarshal(data, b.(proto.Message))
+	}
+	return nil
+}
+
+func NewCodec(rwc io.ReadWriteCloser) codec.Codec {
+	return &protoCodec{
+		buf: bytes.NewBuffer(nil),
+		rwc: rwc,
+	}
+}