From 1201ccc53bd04118b361c20a7ece4d597aedb4bc Mon Sep 17 00:00:00 2001
From: Matt Joiner <anacrolix@gmail.com>
Date: Mon, 18 Oct 2021 18:40:33 +1100
Subject: [PATCH] Refresh requests after a second of no updates

---
 client.go     | 11 +++++++++++
 peerconn.go   |  4 ++++
 requesting.go | 12 +++++++++---
 3 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/client.go b/client.go
index 3afe64a2..af18b6d0 100644
--- a/client.go
+++ b/client.go
@@ -9,6 +9,7 @@ import (
 	"expvar"
 	"fmt"
 	"io"
+	"math"
 	"net"
 	"net/http"
 	"sort"
@@ -956,6 +957,16 @@ func (cl *Client) runHandshookConn(c *PeerConn, t *Torrent) error {
 	defer t.dropConnection(c)
 	c.startWriter()
 	cl.sendInitialMessages(c, t)
+	c.updateRequestsTimer = time.AfterFunc(math.MaxInt64, func() {
+		if c.needRequestUpdate != "" {
+			return
+		}
+		if c.actualRequestState.Requests.IsEmpty() {
+			panic("updateRequestsTimer should have been stopped")
+		}
+		c.updateRequests("updateRequestsTimer")
+	})
+	c.updateRequestsTimer.Stop()
 	err := c.mainReadLoop()
 	if err != nil {
 		return fmt.Errorf("main read loop: %w", err)
diff --git a/peerconn.go b/peerconn.go
index eebfc029..545e29f1 100644
--- a/peerconn.go
+++ b/peerconn.go
@@ -84,6 +84,7 @@ type Peer struct {
 	// Stuff controlled by the local peer.
 	needRequestUpdate    string
 	actualRequestState   requestState
+	updateRequestsTimer  *time.Timer
 	cancelledRequests    roaring.Bitmap
 	lastBecameInterested time.Time
 	priorInterest        time.Duration
@@ -414,6 +415,9 @@ func (cn *PeerConn) onClose() {
 	if cn.pex.IsEnabled() {
 		cn.pex.Close()
 	}
+	if cn.updateRequestsTimer != nil {
+		cn.updateRequestsTimer.Stop()
+	}
 	cn.tickleWriter()
 	if cn.conn != nil {
 		cn.conn.Close()
diff --git a/requesting.go b/requesting.go
index 1da22900..7d0c8f2f 100644
--- a/requesting.go
+++ b/requesting.go
@@ -253,7 +253,7 @@ func (p *Peer) applyNextRequestState() bool {
 }
 
 func (p *Peer) applyRequestState(next requestState) bool {
-	current := p.actualRequestState
+	current := &p.actualRequestState
 	if !p.setInterested(next.Interested) {
 		return false
 	}
@@ -268,8 +268,9 @@ func (p *Peer) applyRequestState(next requestState) bool {
 	}
 	next.Requests.Iterate(func(req uint32) bool {
 		if p.cancelledRequests.Contains(req) {
-			log.Printf("waiting for cancelled request %v", req)
-			return false
+			// Waiting for a reject or piece message, which will suitably trigger us to update our
+			// requests, so we can skip this one with no additional consideration.
+			return true
 		}
 		if maxRequests(current.Requests.GetCardinality()) >= p.nominalMaxRequests() {
 			log.Printf("not assigning all requests [desired=%v, cancelled=%v, max=%v]",
@@ -288,6 +289,11 @@ func (p *Peer) applyRequestState(next requestState) bool {
 	})
 	if more {
 		p.needRequestUpdate = ""
+		if current.Requests.IsEmpty() {
+			p.updateRequestsTimer.Stop()
+		} else {
+			p.updateRequestsTimer.Reset(time.Second)
+		}
 	}
 	return more
 }
-- 
2.48.1