From 1ac5811990e4f85d5fabcc14123f646dfec9cb9e Mon Sep 17 00:00:00 2001
From: Matt Joiner <anacrolix@gmail.com>
Date: Thu, 28 Jan 2021 16:36:35 +1100
Subject: [PATCH] Remove requests as soon as chunk data is received

Note that this breaks the backpressure on webseed responses again, and should be fixed shortly.
---
 peerconn.go     | 11 +++++++++--
 torrent.go      |  7 +++++--
 webseed-peer.go |  3 ++-
 3 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/peerconn.go b/peerconn.go
index 1f9a3a53..f9bec8e1 100644
--- a/peerconn.go
+++ b/peerconn.go
@@ -1365,7 +1365,14 @@ func (c *Peer) receiveChunk(msg *pp.Message) error {
 		torrent.Add("chunks received due to allowed fast", 1)
 	}
 
-	defer func() {
+	// TODO: This needs to happen immediately, to prevent cancels occurring asynchronously when have
+	// actually already received the piece, while we have the Client unlocked to write the data out.
+	{
+		if _, ok := c.requests[req]; ok {
+			for _, f := range c.callbacks.ReceivedRequested {
+				f(PeerMessageEvent{c, msg})
+			}
+		}
 		// Request has been satisfied.
 		if c.deleteRequest(req) {
 			if c.expectingChunks() {
@@ -1374,7 +1381,7 @@ func (c *Peer) receiveChunk(msg *pp.Message) error {
 		} else {
 			torrent.Add("chunks received unwanted", 1)
 		}
-	}()
+	}
 
 	// Do we actually want this chunk?
 	if t.haveChunk(req) {
diff --git a/torrent.go b/torrent.go
index 059e5883..0b858162 100644
--- a/torrent.go
+++ b/torrent.go
@@ -2117,10 +2117,13 @@ func (t *Torrent) addWebSeed(url string) {
 			Network:                  "http",
 			reconciledHandshakeStats: true,
 			peerSentHaveAll:          true,
-			PeerMaxRequests:          maxRequests,
-			RemoteAddr:               remoteAddrFromUrl(url),
+			// TODO: Raise this limit, and instead limit concurrent fetches.
+			PeerMaxRequests: maxRequests,
+			RemoteAddr:      remoteAddrFromUrl(url),
 		},
 		client: webseed.Client{
+			// TODO: Investigate a MaxConnsPerHost in the transport for this, possibly in a global
+			// Client.
 			HttpClient: http.DefaultClient,
 			Url:        url,
 		},
diff --git a/webseed-peer.go b/webseed-peer.go
index 1856a4d0..0e4676f5 100644
--- a/webseed-peer.go
+++ b/webseed-peer.go
@@ -13,7 +13,8 @@ import (
 )
 
 type webseedPeer struct {
-	client   webseed.Client
+	client webseed.Client
+	// TODO: Remove finished entries from this.
 	requests map[Request]webseed.Request
 	peer     Peer
 }