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protocol.go
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protocol.go
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package common
import (
"errors"
"io"
"github.com/golang/protobuf/proto"
)
func SendMessage(c io.Writer, ln *LogLines) (err error) {
var data []byte
if data, err = proto.Marshal(ln); err != nil {
return
}
l := uint32(len(data) + 4)
_, err = c.Write([]byte{
byte(l >> 24), // message length
byte(l >> 16),
byte(l >> 8),
byte(l),
0, // message id, currently always equal to zero
0,
0,
0,
})
if err != nil {
return
}
_, err = c.Write(data)
return
}
func ReceiveMessage(c io.Reader) (ln *LogLines, err error) {
var lenbuf = make([]byte, 4)
if _, err = io.ReadFull(c, lenbuf); err != nil {
return
}
l := uint32(uint32(lenbuf[0])<<24 + uint32(lenbuf[1])<<16 + uint32(lenbuf[2])<<8 + uint32(lenbuf[3]))
if l <= 4 {
err = errors.New("Message length must be greater than 4 bytes")
return
}
buf := make([]byte, l)
if _, err = io.ReadFull(c, buf); err != nil {
return
}
// we ignore first 4 bytes as they are message id which is always equal to zero in current implementation
ln = new(LogLines)
err = proto.Unmarshal(buf[4:], ln)
return
}