From: Matt Joiner <anacrolix@gmail.com>
Date: Fri, 12 Jan 2018 01:24:37 +0000 (+1100)
Subject: Make Torrent.pendingPieces a priority bitmap in preparation for #220
X-Git-Tag: v1.0.0~278
X-Git-Url: http://www.git.stargrave.org/?a=commitdiff_plain;h=ed7e3f6ec03a84803f983e2851f761da162f8b94;p=btrtrc.git

Make Torrent.pendingPieces a priority bitmap in preparation for #220
---

diff --git a/connection.go b/connection.go
index f4bef805..794f5986 100644
--- a/connection.go
+++ b/connection.go
@@ -541,7 +541,19 @@ func (cn *connection) unbiasedPieceRequestOrder() iter.Func {
 	skip.Union(cn.t.completedPieces)
 	// Return an iterator over the different priority classes, minus the skip
 	// pieces.
-	return iterBitmapsDistinct(skip, now, readahead, cn.t.pendingPieces)
+	return iter.Chain(
+		iterBitmapsDistinct(skip, now, readahead),
+		func(cb iter.Callback) {
+			cn.t.pendingPieces.IterTyped(func(piece int) bool {
+				if skip.Contains(piece) {
+					return true
+				}
+				more := cb(piece)
+				skip.Add(piece)
+				return more
+			})
+		},
+	)
 }
 
 // The connection should download highest priority pieces first, without any
diff --git a/connection_test.go b/connection_test.go
index 3f6dfd93..f22d26b9 100644
--- a/connection_test.go
+++ b/connection_test.go
@@ -97,7 +97,7 @@ func BenchmarkConnectionMainReadLoop(b *testing.B) {
 	}
 	t.setChunkSize(defaultChunkSize)
 	t.makePieces()
-	t.pendingPieces.Add(0)
+	t.pendingPieces.Set(0, PiecePriorityNormal.BitmapPriority())
 	r, w := io.Pipe()
 	cn := &connection{
 		t: t,
diff --git a/piece.go b/piece.go
index d5130d7b..71c60417 100644
--- a/piece.go
+++ b/piece.go
@@ -21,13 +21,20 @@ func (pp *piecePriority) Raise(maybe piecePriority) {
 	}
 }
 
+// Priority for use in PriorityBitmap
+func (me piecePriority) BitmapPriority() int {
+	return -int(me)
+}
+
 const (
 	PiecePriorityNone      piecePriority = iota // Not wanted.
 	PiecePriorityNormal                         // Wanted.
+	PiecePriorityHigh                           // Wanted a lot.
 	PiecePriorityReadahead                      // May be required soon.
-	// Succeeds a piece where a read occurred. Currently the same as Now, apparently due to issues with caching.
+	// Succeeds a piece where a read occurred. Currently the same as Now,
+	// apparently due to issues with caching.
 	PiecePriorityNext
-	PiecePriorityNow // A Reader is reading in this piece.
+	PiecePriorityNow // A Reader is reading in this piece. Highest urgency.
 )
 
 type Piece struct {
diff --git a/torrent.go b/torrent.go
index 301e2d6d..32f66b4e 100644
--- a/torrent.go
+++ b/torrent.go
@@ -16,6 +16,8 @@ import (
 	"text/tabwriter"
 	"time"
 
+	"github.com/anacrolix/missinggo/prioritybitmap"
+
 	"github.com/anacrolix/dht"
 	"github.com/anacrolix/missinggo"
 	"github.com/anacrolix/missinggo/bitmap"
@@ -113,7 +115,7 @@ type Torrent struct {
 
 	// The indexes of pieces we want with normal priority, that aren't
 	// currently available.
-	pendingPieces bitmap.Bitmap
+	pendingPieces prioritybitmap.PriorityBitmap
 	// A cache of completed piece indices.
 	completedPieces bitmap.Bitmap
 	// Pieces that need to be hashed.
@@ -965,13 +967,13 @@ func (t *Torrent) pendPiece(piece int) {
 	if t.havePiece(piece) {
 		return
 	}
-	t.pendingPieces.Add(piece)
+	t.pendingPieces.Set(piece, PiecePriorityNormal.BitmapPriority())
 	t.updatePiecePriority(piece)
 }
 
 func (t *Torrent) unpendPieces(unpend bitmap.Bitmap) {
-	t.pendingPieces.Sub(unpend)
-	unpend.IterTyped(func(piece int) (again bool) {
+	unpend.IterTyped(func(piece int) (more bool) {
+		t.pendingPieces.Remove(piece)
 		t.updatePiecePriority(piece)
 		return true
 	})