From 8c5df03e14d7c6e6d031cf02b6d5ddd2c4fe4f6d Mon Sep 17 00:00:00 2001
From: Matt Joiner <anacrolix@gmail.com>
Date: Thu, 9 Dec 2021 21:49:29 +1100
Subject: [PATCH] Minimize allocations due to heap escapes

---
 request-strategy/order.go               |  2 +-
 request-strategy/piece-request-order.go | 21 ++++++++++++---------
 2 files changed, 13 insertions(+), 10 deletions(-)

diff --git a/request-strategy/order.go b/request-strategy/order.go
index f414226d..4068ed4d 100644
--- a/request-strategy/order.go
+++ b/request-strategy/order.go
@@ -81,7 +81,7 @@ func GetRequestablePieces(input Input, pro *PieceRequestOrder, f func(ih metainf
 	}
 	var allTorrentsUnverifiedBytes int64
 	pro.tree.Ascend(func(i btree.Item) bool {
-		_i := i.(pieceRequestOrderItem)
+		_i := i.(*pieceRequestOrderItem)
 		ih := _i.key.InfoHash
 		var t Torrent = input.Torrent(ih)
 		var piece Piece = t.Piece(_i.key.Index)
diff --git a/request-strategy/piece-request-order.go b/request-strategy/piece-request-order.go
index e0af7487..0b1d6b4e 100644
--- a/request-strategy/piece-request-order.go
+++ b/request-strategy/piece-request-order.go
@@ -35,8 +35,8 @@ type pieceRequestOrderItem struct {
 	state PieceRequestOrderState
 }
 
-func (me pieceRequestOrderItem) Less(other btree.Item) bool {
-	otherConcrete := other.(pieceRequestOrderItem)
+func (me *pieceRequestOrderItem) Less(other btree.Item) bool {
+	otherConcrete := other.(*pieceRequestOrderItem)
 	return pieceOrderLess(
 		pieceOrderInput{
 			PieceRequestOrderState: me.state,
@@ -53,7 +53,7 @@ func (me *PieceRequestOrder) Add(key PieceRequestOrderKey, state PieceRequestOrd
 	if _, ok := me.keys[key]; ok {
 		panic(key)
 	}
-	if me.tree.ReplaceOrInsert(pieceRequestOrderItem{
+	if me.tree.ReplaceOrInsert(&pieceRequestOrderItem{
 		key:   key,
 		state: state,
 	}) != nil {
@@ -63,13 +63,15 @@ func (me *PieceRequestOrder) Add(key PieceRequestOrderKey, state PieceRequestOrd
 }
 
 func (me *PieceRequestOrder) Update(key PieceRequestOrderKey, state PieceRequestOrderState) {
-	if me.tree.Delete(me.existingItemForKey(key)) == nil {
+	item := me.existingItemForKey(key)
+	if item.state == state {
+		return
+	}
+	if me.tree.Delete(&item) == nil {
 		panic(fmt.Sprintf("%#v", key))
 	}
-	if me.tree.ReplaceOrInsert(pieceRequestOrderItem{
-		key:   key,
-		state: state,
-	}) != nil {
+	item.state = state
+	if me.tree.ReplaceOrInsert(&item) != nil {
 		panic(key)
 	}
 	me.keys[key] = state
@@ -83,7 +85,8 @@ func (me *PieceRequestOrder) existingItemForKey(key PieceRequestOrderKey) pieceR
 }
 
 func (me *PieceRequestOrder) Delete(key PieceRequestOrderKey) {
-	if me.tree.Delete(me.existingItemForKey(key)) == nil {
+	item := me.existingItemForKey(key)
+	if me.tree.Delete(&item) == nil {
 		panic(key)
 	}
 	delete(me.keys, key)