prepare p2p mod

p2p/p2p.go

@@ -0,0 +1,71 @@
+package p2p
+
+import (
+	"magnetflow/client"
+	"magnetflow/message"
+	"magnetflow/peers"
+)
+
+const MaxBloackSize = 1 << 14
+
+const MaxBackLog = 5
+
+type Torrent struct {
+	Peers       []peers.Peer
+	PeerID      [20]byte
+	InfoHash    [20]byte
+	PieceHashes [][20]byte
+	PieceLength int
+	Length      int
+	Name        string
+}
+
+type pieceWork struct {
+	index  int
+	hash   [20]byte
+	length int
+}
+
+type pieceResult struct {
+	index int
+	buf   []byte
+}
+
+type pieceProgress struct {
+	index      int
+	client     *client.Client
+	buf        []byte
+	downloaded int
+	requested  int
+	backlog    int
+}
+
+func (state *pieceProgress) readMessage() error {
+	msg, err := state.client.Read()
+	if err != nil {
+		return err
+	}
+	if msg == nil {
+		return nil
+	}
+	switch msg.ID {
+	case message.MsgUnchoke:
+		state.client.Choked = false
+	case message.MsgChoke:
+		state.client.Choked = true
+	case message.MsgHave:
+		index, err := message.ParseHave(msg)
+		if err != nil {
+			return err
+		}
+		state.client.Bitfield.SetPiece(index)
+	case message.MsgPiece:
+		n, err := message.ParsePiece(state.index, state.buf, msg)
+		if err != nil {
+			return err
+		}
+		state.downloaded += n
+		state.backlog--
+	}
+	return nil
+}