refactor: message entity

protocol/bt/peer/message/msg_piece.go

@@ -4,38 +4,39 @@ import "encoding/binary"
 
 // piece: <len=0009+X><id=7><index><begin><block>
 type Piece struct {
-	*Message
+	*base
 	Index uint32
 	Begin uint32
 	Block []byte
 }
 
-func NewPiece(index uint32, begin uint32, block []byte) *Piece {
+func NewPiece() *Piece {
 	return &Piece{
-		Message: &Message{
-			Length: 9 + uint32(len(block)),
-			ID:     IdPiece,
+		base: &base{
+			id: IdPiece,
 		},
-		Index: index,
-		Begin: begin,
-		// Block: io.LimitReader(reader, int64(length)),
-		Block: block,
 	}
 }
 
-func (p *Piece) Encode() []byte {
-	buf := make([]byte, 8)
-	binary.BigEndian.PutUint32(buf[:4], p.Index)
-	binary.BigEndian.PutUint32(buf[4:8], p.Begin)
-	buf = append(buf, p.Block...)
-	return append(p.Message.Encode(), buf...)
+func BuildPiece(index uint32, begin uint32, block []byte) *Piece {
+	piece := NewPiece()
+	piece.Index = index
+	piece.Begin = begin
+	piece.Block = block
+	return piece
+
 }
 
-func (p *Piece) Decode(buf []byte) Serialize {
-	p.Message = &Message{}
-	p.Message.Decode(buf)
-	p.Index = binary.BigEndian.Uint32(buf[5:9])
-	p.Begin = binary.BigEndian.Uint32(buf[9:13])
-	p.Block = buf[13:]
-	return p
+func (p *Piece) Encode() []byte {
+	buf := make([]byte, 8+len(p.Block))
+	binary.BigEndian.PutUint32(buf[0:4], p.Index)
+	binary.BigEndian.PutUint32(buf[4:8], p.Begin)
+	copy(buf[8:], p.Block)
+	return encode(p.base, buf)
+}
+
+func (p *Piece) Decode(buf []byte) {
+	p.Index = binary.BigEndian.Uint32(buf[0:4])
+	p.Begin = binary.BigEndian.Uint32(buf[4:8])
+	p.Block = buf[8:]
 }