From 0d13293d71e468222dfa4a4f82b1b9d7775cfa5a Mon Sep 17 00:00:00 2001
From: Matt Joiner <anacrolix@gmail.com>
Date: Fri, 15 May 2015 08:39:53 +1000
Subject: [PATCH] Support seeding

---
 client.go           | 27 +++++++++++++++------------
 cmd/torrent/main.go |  3 +--
 config.go           |  5 ++++-
 connection.go       |  8 ++++++--
 4 files changed, 26 insertions(+), 17 deletions(-)

diff --git a/client.go b/client.go
index f5ecac7c..1e8755f1 100644
--- a/client.go
+++ b/client.go
@@ -1167,14 +1167,7 @@ func (me *Client) sendInitialMessages(conn *connection, torrent *torrent) {
 					}(),
 					"v": extendedHandshakeClientVersion,
 					// No upload queue is implemented yet.
-					"reqq": func() int {
-						if me.config.NoUpload {
-							// No need to look strange if it costs us nothing.
-							return 250
-						} else {
-							return 1
-						}
-					}(),
+					"reqq": 64,
 				}
 				if !me.config.DisableEncryption {
 					d["e"] = 1
@@ -1454,13 +1447,13 @@ func (me *Client) connectionLoop(t *torrent, c *connection) error {
 			if me.config.NoUpload {
 				break
 			}
-			if c.PeerRequests == nil {
-				c.PeerRequests = make(map[request]struct{}, maxRequests)
-			}
 			request := newRequest(msg.Index, msg.Begin, msg.Length)
 			// TODO: Requests should be satisfied from a dedicated upload
 			// routine.
 			// c.PeerRequests[request] = struct{}{}
+			// if c.PeerRequests == nil {
+			// 	c.PeerRequests = make(map[request]struct{}, maxRequests)
+			// }
 			p := make([]byte, msg.Length)
 			n, err := dataReadAt(t.data, p, int64(t.pieceLength(0))*int64(msg.Index)+int64(msg.Begin))
 			if err != nil {
@@ -1476,6 +1469,7 @@ func (me *Client) connectionLoop(t *torrent, c *connection) error {
 				Piece: p,
 			})
 			uploadChunksPosted.Add(1)
+			c.chunksSent++
 		case pp.Cancel:
 			req := newRequest(msg.Index, msg.Begin, msg.Length)
 			if !c.PeerCancel(req) {
@@ -2196,9 +2190,13 @@ func (cl *Client) waitWantPeers(t *torrent) bool {
 			return false
 		default:
 		}
-		if len(t.Peers) < torrentPeersLowWater && t.needData() {
+		if len(t.Peers) > torrentPeersLowWater {
+			goto wait
+		}
+		if t.needData() || cl.seeding(t) {
 			return true
 		}
+	wait:
 		cl.mu.Unlock()
 		t.wantPeers.Wait()
 		t.stateMu.Unlock()
@@ -2207,6 +2205,11 @@ func (cl *Client) waitWantPeers(t *torrent) bool {
 	}
 }
 
+// Returns whether the client should make effort to seed the torrent.
+func (cl *Client) seeding(t *torrent) bool {
+	return cl.config.Seed && !cl.config.NoUpload
+}
+
 func (cl *Client) announceTorrentDHT(t *torrent, impliedPort bool) {
 	for cl.waitWantPeers(t) {
 		log.Printf("getting peers for %q from DHT", t)
diff --git a/cmd/torrent/main.go b/cmd/torrent/main.go
index d81d219e..8f8b67ec 100644
--- a/cmd/torrent/main.go
+++ b/cmd/torrent/main.go
@@ -73,7 +73,6 @@ func main() {
 	log.SetFlags(log.LstdFlags | log.Lshortfile)
 	var rootGroup struct {
 		Client    torrent.Config `group:"Client Options"`
-		Seed      bool           `long:"seed" description:"continue seeding torrents after completed"`
 		TestPeers []string       `long:"test-peer" description:"address of peer to inject to every torrent"`
 	}
 	// Don't pass flags.PrintError because it's inconsistent with printing.
@@ -151,7 +150,7 @@ waitDone:
 			os.Stdout.WriteString(progressLine(client))
 		}
 	}
-	if rootGroup.Seed {
+	if rootGroup.Client.Seed {
 		select {}
 	}
 }
diff --git a/config.go b/config.go
index 56081998..b6921182 100644
--- a/config.go
+++ b/config.go
@@ -20,8 +20,11 @@ type Config struct {
 	NoDHT bool `long:"disable-dht"`
 	// Overrides the default DHT configuration.
 	DHTConfig *dht.ServerConfig
-	// Don't send chunks to peers.
+	// Don't ever send chunks to peers.
 	NoUpload bool `long:"no-upload"`
+	// Upload even after there's nothing in it for us. By default uploading is
+	// not altruistic.
+	Seed bool `long:"seed"`
 	// User-provided Client peer ID. If not present, one is generated automatically.
 	PeerID string
 	// For the bittorrent protocol.
diff --git a/connection.go b/connection.go
index 1913298d..ed94626f 100644
--- a/connection.go
+++ b/connection.go
@@ -46,6 +46,7 @@ type connection struct {
 
 	UnwantedChunksReceived int
 	UsefulChunksReceived   int
+	chunksSent             int
 
 	lastMessageReceived     time.Time
 	completedHandshake      time.Time
@@ -237,13 +238,16 @@ func (cn *connection) WriteStatus(w io.Writer, t *torrent) {
 		eventAgeString(cn.lastMessageReceived),
 		eventAgeString(cn.completedHandshake),
 		eventAgeString(cn.lastUsefulChunkReceived))
-	fmt.Fprintf(w, "    %s completed, good chunks: %d/%d reqs: %d-%d, flags: %s\n",
+	fmt.Fprintf(w,
+		"    %s completed, good chunks: %d/%d-%d reqq: %d-%d, flags: %s\n",
 		cn.completedString(t),
 		cn.UsefulChunksReceived,
 		cn.UnwantedChunksReceived+cn.UsefulChunksReceived,
+		cn.chunksSent,
 		len(cn.Requests),
 		len(cn.PeerRequests),
-		cn.statusFlags())
+		cn.statusFlags(),
+	)
 }
 
 func (c *connection) Close() {
-- 
2.48.1