单个peer的文件下载实现

down/bt/peer/message/message.go

@@ -29,14 +29,14 @@ type Message struct {
 	ID     ID
 }
 
-func (msg Message) Encode() []byte {
+func (msg *Message) Encode() []byte {
 	buf := make([]byte, 5)
 	binary.BigEndian.PutUint32(buf, msg.Length)
 	buf[4] = byte(msg.ID)
 	return buf
 }
 
-func (msg Message) Decode(buf []byte) {
+func (msg *Message) Decode(buf []byte) {
 	msg.Length = binary.BigEndian.Uint32(buf)
 	msg.ID = ID(buf[4])
 }

down/bt/peer/message/msg_bitfield.go

@@ -2,13 +2,13 @@ package message
 
 // bitfield: <len=0001+X><id=5><bitfield>
 type Bitfield struct {
-	Message
+	*Message
 	payload []byte
 }
 
 func NewBitfield(payload []byte) *Bitfield {
 	return &Bitfield{
-		Message: Message{
+		Message: &Message{
 			Length: uint32(len(payload) + 1),
 			ID:     IdBitfield,
 		},
@@ -21,8 +21,9 @@ func (b *Bitfield) Encode() []byte {
 }
 
 func (b *Bitfield) Decode(buf []byte) Serialize {
+	b.Message = &Message{}
 	b.Message.Decode(buf)
-	copy(b.payload, buf[5:])
+	b.payload = buf[5:]
 	return b
 }
 

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
+}

down/bt/peer/message/msg_request.go

@@ -26,9 +26,9 @@ func NewRequest(index uint32, begin uint32, length uint32) *Request {
 
 func (r *Request) Encode() []byte {
 	buf := make([]byte, 12)
-	binary.BigEndian.PutUint32(buf[:4], r.Index)
+	binary.BigEndian.PutUint32(buf[0:4], r.Index)
 	binary.BigEndian.PutUint32(buf[4:8], r.Begin)
-	binary.BigEndian.PutUint32(buf[8:], r.Length)
+	binary.BigEndian.PutUint32(buf[8:12], r.Length)
 	return append(r.Message.Encode(), buf...)
 }