Implement receiving cancel messages

diff --git a/client.go b/client.go
index 76425ccc2c37eb91866848145f685d256df9c586..f8737600b776514a91533fbcce65ee13c90ea839 100644 (file)
--- a/client.go
+++ b/client.go
@@ -425,6 +425,11 @@ func (me *Client) connectionLoop(torrent *torrent, conn *connection) error {
                                Begin: msg.Begin,
                                Piece: p,
                        })
+               case peer_protocol.Cancel:
+                       req := newRequest(msg.Index, msg.Begin, msg.Length)
+                       if !conn.PeerCancel(req) {
+                               log.Printf("received unexpected cancel: %v", req)
+                       }
                case peer_protocol.Bitfield:
                        if len(msg.Bitfield) < len(torrent.Pieces) {
                                err = errors.New("received invalid bitfield")

diff --git a/connection.go b/connection.go
index ee54f10ccbbc964f256b268b3636a9285696882b..aefe0ba0bb0c26b84e1d6a4bbaf51fd98ae4a0bb 100644 (file)
--- a/connection.go
+++ b/connection.go
@@ -88,6 +88,18 @@ func (c *connection) Request(chunk Request) bool {
        return true
 }
 
+// Returns true if an unsatisfied request was canceled.
+func (c *connection) PeerCancel(r Request) bool {
+       if c.PeerRequests == nil {
+               return false
+       }
+       if _, ok := c.PeerRequests[r]; !ok {
+               return false
+       }
+       delete(c.PeerRequests, r)
+       return true
+}
+
 func (c *connection) Unchoke() {
        if !c.Choked {
                return

diff --git a/misc.go b/misc.go
index ce0997f21f6f122f13a8ef977fb498e4bdd2a93c..b0fb349e04024fe7f0d2d08dff820844edd7255e 100644 (file)
--- a/misc.go
+++ b/misc.go
@@ -65,6 +65,10 @@ type Request struct {
        chunkSpec
 }
 
+func newRequest(index, begin, length peer_protocol.Integer) Request {
+       return Request{index, chunkSpec{begin, length}}
+}
+
 type pieceByBytesPendingSlice struct {
        Pending, Indices []peer_protocol.Integer
 }