单个peer的文件下载实现

down/bt/peer/message/msg_piece.go

@@ -1,23 +1,41 @@
 package message
 
-import "io"
+import "encoding/binary"
 
 // piece: <len=0009+X><id=7><index><begin><block>
 type Piece struct {
-	Message
+	*Message
 	Index uint32
 	Begin uint32
-	Block io.Reader
+	Block []byte
 }
 
-func newPiece(index uint32, begin uint32, reader io.Reader, length uint32) *Piece {
+func NewPiece(index uint32, begin uint32, block []byte) *Piece {
 	return &Piece{
-		Message: Message{
-			Length: 9 + length,
+		Message: &Message{
+			Length: 9 + uint32(len(block)),
 			ID:     IdPiece,
 		},
 		Index: index,
 		Begin: begin,
-		Block: io.LimitReader(reader, int64(length)),
+		// 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 (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
+}