From 307d6d178fc6502a800380a642460b6cf4f75e94 Mon Sep 17 00:00:00 2001
From: Matt Joiner <anacrolix@gmail.com>
Date: Fri, 14 May 2021 11:50:41 +1000
Subject: [PATCH] Prepare to implement max unverified bytes

---
 request-strategy.go         |  5 ++-
 request-strategy/order.go   | 61 ++++++++++++++++++++++++-------------
 request-strategy/torrent.go | 11 +++++++
 3 files changed, 55 insertions(+), 22 deletions(-)
 create mode 100644 request-strategy/torrent.go

diff --git a/request-strategy.go b/request-strategy.go
index 21596a23..84473b40 100644
--- a/request-strategy.go
+++ b/request-strategy.go
@@ -26,7 +26,10 @@ func (cl *Client) requester() {
 func (cl *Client) doRequests() {
 	ts := make([]*request_strategy.Torrent, 0, len(cl.torrents))
 	for _, t := range cl.torrents {
-		rst := &request_strategy.Torrent{}
+		rst := &request_strategy.Torrent{
+			StableId: uintptr(unsafe.Pointer(t)),
+			//MaxUnverifiedBytes: 1 << 20,
+		}
 		if t.storage != nil {
 			rst.Capacity = t.storage.Capacity
 		}
diff --git a/request-strategy/order.go b/request-strategy/order.go
index 56002594..4742254d 100644
--- a/request-strategy/order.go
+++ b/request-strategy/order.go
@@ -20,8 +20,16 @@ type ClientPieceOrder struct {
 	pieces []pieceRequestOrderPiece
 }
 
+type orderTorrent struct {
+	*Torrent
+	unverifiedBytes int64
+	// Potentially shared with other torrents.
+	storageLeft *int64
+	peers       []*requestsPeer
+}
+
 type pieceRequestOrderPiece struct {
-	t     *Torrent
+	t     *orderTorrent
 	index pieceIndex
 	Piece
 }
@@ -41,7 +49,13 @@ func (me ClientPieceOrder) less(_i, _j int) bool {
 		int(j.Priority), int(i.Priority),
 	).Bool(
 		j.Partial, i.Partial,
-	).Int64(i.Availability, j.Availability).Int(i.index, j.index).Less()
+	).Int64(
+		i.Availability, j.Availability,
+	).Int(
+		i.index, j.index,
+	).Uintptr(
+		i.t.StableId, j.t.StableId,
+	).MustLess()
 }
 
 type requestsPeer struct {
@@ -72,25 +86,24 @@ func (me *peersForPieceRequests) addNextRequest(r Request) {
 	me.requestsInPiece++
 }
 
-type Torrent struct {
-	Pieces   []Piece
-	Capacity *func() *int64
-	Peers    []Peer // not closed.
-}
-
 func (requestOrder *ClientPieceOrder) DoRequests(torrents []*Torrent) map[PeerId]PeerNextRequestState {
 	requestOrder.pieces = requestOrder.pieces[:0]
-	allPeers := make(map[*Torrent][]*requestsPeer)
 	// Storage capacity left for this run, keyed by the storage capacity pointer on the storage
 	// TorrentImpl.
 	storageLeft := make(map[*func() *int64]*int64)
-	for _, t := range torrents {
+	orderTorrents := make([]*orderTorrent, 0, len(torrents))
+	for _, _t := range torrents {
 		// TODO: We could do metainfo requests here.
+		t := &orderTorrent{
+			Torrent:         _t,
+			unverifiedBytes: 0,
+		}
 		key := t.Capacity
 		if key != nil {
 			if _, ok := storageLeft[key]; !ok {
 				storageLeft[key] = (*key)()
 			}
+			t.storageLeft = storageLeft[key]
 		}
 		var peers []*requestsPeer
 		for _, p := range t.Peers {
@@ -107,7 +120,7 @@ func (requestOrder *ClientPieceOrder) DoRequests(torrents []*Torrent) map[PeerId
 				index: i,
 				Piece: tp,
 			})
-			if tp.Request {
+			if tp.Request && tp.NumPendingChunks != 0 {
 				for _, p := range peers {
 					if p.canRequestPiece(i) {
 						p.requestablePiecesRemaining++
@@ -115,25 +128,31 @@ func (requestOrder *ClientPieceOrder) DoRequests(torrents []*Torrent) map[PeerId
 				}
 			}
 		}
-		allPeers[t] = peers
+		t.peers = peers
+		orderTorrents = append(orderTorrents, t)
 	}
 	requestOrder.sort()
-	for _, p := range requestOrder.pieces {
-		torrentPiece := p
-		if left := storageLeft[p.t.Capacity]; left != nil {
-			if *left < int64(torrentPiece.Length) {
+	for _, piece := range requestOrder.pieces {
+		if left := piece.t.storageLeft; left != nil {
+			if *left < int64(piece.Length) {
 				continue
 			}
-			*left -= int64(torrentPiece.Length)
+			*left -= int64(piece.Length)
+		}
+		if !piece.Request || piece.NumPendingChunks == 0 {
+			continue
 		}
-		if !p.Request {
+		if piece.t.MaxUnverifiedBytes != 0 && piece.t.unverifiedBytes+piece.Length > piece.t.MaxUnverifiedBytes {
+			//log.Print("skipping piece")
 			continue
 		}
-		allocatePendingChunks(p, allPeers[p.t])
+		allocatePendingChunks(piece, piece.t.peers)
+		piece.t.unverifiedBytes += piece.Length
+		//log.Print(piece.t.unverifiedBytes)
 	}
 	ret := make(map[PeerId]PeerNextRequestState)
-	for _, peers := range allPeers {
-		for _, rp := range peers {
+	for _, ots := range orderTorrents {
+		for _, rp := range ots.peers {
 			if rp.requestablePiecesRemaining != 0 {
 				panic(rp.requestablePiecesRemaining)
 			}
diff --git a/request-strategy/torrent.go b/request-strategy/torrent.go
new file mode 100644
index 00000000..2090c7a8
--- /dev/null
+++ b/request-strategy/torrent.go
@@ -0,0 +1,11 @@
+package request_strategy
+
+type Torrent struct {
+	Pieces   []Piece
+	Capacity *func() *int64
+	Peers    []Peer // not closed.
+	// Some value that's unique and stable between runs. Could even use the infohash?
+	StableId uintptr
+
+	MaxUnverifiedBytes int64
+}
-- 
2.44.0