/
message.go
105 lines (93 loc) · 1.89 KB
/
message.go
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package util
import (
"encoding/binary"
"fmt"
"github.com/golang/snappy"
"io"
"math"
"github.com/vmihailenco/msgpack"
)
const (
MessageEOF = math.MinInt32
BufferSize = 1024 * 512
)
func CopyBuffer(src io.Reader, dst io.Writer) (err error) {
buf := make([]byte, BufferSize)
for {
nr, er := src.Read(buf)
if nr > 0 {
nw, ew := dst.Write(buf[0:nr])
if ew != nil {
err = ew
break
}
if nr != nw {
err = io.ErrShortWrite
break
}
}
if er != nil {
err = er
break
}
}
return err
}
func ReadMessage(reader io.Reader) (res []byte, err error) {
var length int32
err = binary.Read(reader, binary.LittleEndian, &length)
if err == io.EOF || length == MessageEOF {
return nil, io.EOF
}
if err != nil {
return nil, err
}
if length == 0 {
return nil, nil
}
res = make([]byte, length)
var n int
n, err = io.ReadFull(reader, res)
if err == io.EOF {
return nil, fmt.Errorf("unexpected EOF when reading message, expected read %v, only read %v", length, n)
}
if err != nil {
return nil, err
}
buf, err := snappy.Decode(nil, res)
if err != nil {
return nil, err
}
return buf, nil
}
func WriteMessage(writer io.Writer, msg []byte) (err error) {
buf := snappy.Encode(nil, msg)
if err = binary.Write(writer, binary.LittleEndian, int32(len(buf))); err != nil {
return err
}
if _, err = writer.Write(buf); err != nil {
return err
}
return nil
}
func WriteEOFMessage(writer io.Writer) (err error) {
if err = binary.Write(writer, binary.LittleEndian, int32(MessageEOF)); err != nil {
return err
}
return nil
}
func ReadObject(reader io.Reader, obj interface{}) error {
msg, err := ReadMessage(reader)
if err != nil {
return err
}
err = msgpack.Unmarshal(msg, obj)
return err
}
func WriteObject(writer io.Writer, obj interface{}) error {
buf, err := msgpack.Marshal(obj)
if err != nil {
return err
}
return WriteMessage(writer, buf)
}