From aedf2583ccdeafc815223b9edae1e19e7b8d33f3 Mon Sep 17 00:00:00 2001
From: Matt Joiner <anacrolix@gmail.com>
Date: Mon, 11 Jul 2022 15:02:24 +1000
Subject: [PATCH] Remove relevant webtorrent offers when closing Torrent

(cherry picked from commit 73a0b5e4d2fe679aac31d87171537c70f91f46ee)
---
 torrent.go                   | 13 ++++++++-----
 webtorrent/tracker-client.go | 11 +++++++++++
 wstracker.go                 |  3 ++-
 3 files changed, 21 insertions(+), 6 deletions(-)

diff --git a/torrent.go b/torrent.go
index e53b6bef..f18fc252 100644
--- a/torrent.go
+++ b/torrent.go
@@ -61,6 +61,7 @@ type Torrent struct {
 	userOnWriteChunkErr    func(error)
 
 	closed   chansync.SetOnce
+	onClose  []func()
 	infoHash metainfo.Hash
 	pieces   []Piece
 
@@ -865,6 +866,9 @@ func (t *Torrent) close(wg *sync.WaitGroup) (err error) {
 		err = errors.New("already closed")
 		return
 	}
+	for _, f := range t.onClose {
+		f()
+	}
 	if t.storage != nil {
 		wg.Add(1)
 		go func() {
@@ -1614,11 +1618,10 @@ func (t *Torrent) runHandshookConnLoggingErr(pc *PeerConn) {
 }
 
 func (t *Torrent) startWebsocketAnnouncer(u url.URL) torrentTrackerAnnouncer {
-	wtc, release := t.cl.websocketTrackers.Get(u.String())
-	go func() {
-		<-t.closed.Done()
-		release()
-	}()
+	wtc, release := t.cl.websocketTrackers.Get(u.String(), t.infoHash)
+	// This needs to run before the Torrent is dropped from the Client, to prevent a new webtorrent.TrackerClient for
+	// the same info hash before the old one is cleaned up.
+	t.onClose = append(t.onClose, release)
 	wst := websocketTrackerStatus{u, wtc}
 	go func() {
 		err := wtc.Announce(tracker.Started, t.infoHash)
diff --git a/webtorrent/tracker-client.go b/webtorrent/tracker-client.go
index 1ec4b9d9..3b8c6a6b 100644
--- a/webtorrent/tracker-client.go
+++ b/webtorrent/tracker-client.go
@@ -187,6 +187,17 @@ func (tc *TrackerClient) closeUnusedOffers() {
 	tc.outboundOffers = nil
 }
 
+func (tc *TrackerClient) CloseOffersForInfohash(infoHash [20]byte) {
+	tc.mu.Lock()
+	defer tc.mu.Unlock()
+	for key, offer := range tc.outboundOffers {
+		if offer.infoHash == infoHash {
+			offer.peerConnection.Close()
+			delete(tc.outboundOffers, key)
+		}
+	}
+}
+
 func (tc *TrackerClient) Announce(event tracker.AnnounceEvent, infoHash [20]byte) error {
 	metrics.Add("outbound announces", 1)
 	var randOfferId [20]byte
diff --git a/wstracker.go b/wstracker.go
index 5338ceb9..e8bde8c3 100644
--- a/wstracker.go
+++ b/wstracker.go
@@ -42,7 +42,7 @@ type websocketTrackers struct {
 	Proxy              http.ProxyFunc
 }
 
-func (me *websocketTrackers) Get(url string) (*webtorrent.TrackerClient, func()) {
+func (me *websocketTrackers) Get(url string, infoHash [20]byte) (*webtorrent.TrackerClient, func()) {
 	me.mu.Lock()
 	defer me.mu.Unlock()
 	value, ok := me.clients[url]
@@ -74,6 +74,7 @@ func (me *websocketTrackers) Get(url string) (*webtorrent.TrackerClient, func())
 	return &value.TrackerClient, func() {
 		me.mu.Lock()
 		defer me.mu.Unlock()
+		value.TrackerClient.CloseOffersForInfohash(infoHash)
 		value.refCount--
 		if value.refCount == 0 {
 			value.TrackerClient.Close()
-- 
2.44.0