Switch pieceIndex back to an int

I suspect that interface conversions using packet iter are causing a lot of allocation. Either way, with the casting this adds, we should be able to change pieceIndex's type alias now with minimal code change.

connection.go

@@ -486,7 +486,7 @@ func (cn *connection) request(r request, mw messageWriter) bool {
 	if _, ok := cn.requests[r]; ok {
 		panic("chunk already requested")
 	}
-	if !cn.PeerHasPiece(r.Index) {
+	if !cn.PeerHasPiece(pieceIndex(r.Index)) {
 		panic("requesting piece peer doesn't have")
 	}
 	if _, ok := cn.t.conns[cn]; !ok {
@@ -803,7 +803,7 @@ func iterUndirtiedChunks(piece pieceIndex, t *Torrent, f func(chunkSpec) bool) b
 	chunkIndices := t.pieces[piece].undirtiedChunkIndices().ToSortedSlice()
 	// TODO: Use "math/rand".Shuffle >= Go 1.10
 	return iter.ForPerm(len(chunkIndices), func(i int) bool {
-		return f(t.chunkIndexSpec(pieceIndex(chunkIndices[i]), piece))
+		return f(t.chunkIndexSpec(pp.Integer(chunkIndices[i]), piece))
 	})
 }
 
@@ -1024,7 +1024,7 @@ func (c *connection) reject(r request) {
 
 func (c *connection) onReadRequest(r request) error {
 	requestedChunkLengths.Add(strconv.FormatUint(r.Length.Uint64(), 10), 1)
-	if r.Begin+r.Length > c.t.pieceLength(r.Index) {
+	if r.Begin+r.Length > c.t.pieceLength(pieceIndex(r.Index)) {
 		torrent.Add("bad requests received", 1)
 		return errors.New("bad request")
 	}
@@ -1048,7 +1048,7 @@ func (c *connection) onReadRequest(r request) error {
 		// BEP 6 says we may close here if we choose.
 		return nil
 	}
-	if !c.t.havePiece(r.Index) {
+	if !c.t.havePiece(pieceIndex(r.Index)) {
 		// This isn't necessarily them screwing up. We can drop pieces
 		// from our storage, and can't communicate this to peers
 		// except by reconnecting.
@@ -1127,7 +1127,7 @@ func (c *connection) mainReadLoop() (err error) {
 			// We'll probably choke them for this, which will clear them if
 			// appropriate, and is clearly specified.
 		case pp.Have:
-			err = c.peerSentHave(msg.Index)
+			err = c.peerSentHave(pieceIndex(msg.Index))
 		case pp.Request:
 			r := newRequestFromMessage(&msg)
 			err = c.onReadRequest(r)
@@ -1340,21 +1340,21 @@ func (c *connection) receiveChunk(msg *pp.Message) error {
 	if err != nil {
 		log.Printf("%s (%s): error writing chunk %v: %s", t, t.infoHash, req, err)
 		t.pendRequest(req)
-		t.updatePieceCompletion(msg.Index)
+		t.updatePieceCompletion(pieceIndex(msg.Index))
 		return nil
 	}
 
 	// It's important that the piece is potentially queued before we check if
 	// the piece is still wanted, because if it is queued, it won't be wanted.
-	if t.pieceAllDirty(req.Index) {
-		t.queuePieceCheck(req.Index)
-		t.pendAllChunkSpecs(req.Index)
+	if t.pieceAllDirty(pieceIndex(req.Index)) {
+		t.queuePieceCheck(pieceIndex(req.Index))
+		t.pendAllChunkSpecs(pieceIndex(req.Index))
 	}
 
-	c.onDirtiedPiece(req.Index)
+	c.onDirtiedPiece(pieceIndex(req.Index))
 
 	cl.event.Broadcast()
-	t.publishPieceChange(req.Index)
+	t.publishPieceChange(pieceIndex(req.Index))
 
 	return nil
 }
@@ -1420,7 +1420,7 @@ another:
 			}
 			more, err := c.sendChunk(r, msg)
 			if err != nil {
-				i := r.Index
+				i := pieceIndex(r.Index)
 				if c.t.pieceComplete(i) {
 					c.t.updatePieceCompletion(i)
 					if !c.t.pieceComplete(i) {

file.go

@@ -4,7 +4,6 @@ import (
 	"strings"
 
 	"github.com/anacrolix/torrent/metainfo"
-	pwp "github.com/anacrolix/torrent/peer_protocol"
 )
 
 // Provides access to regions of torrent data that correspond to its files.
@@ -131,16 +130,16 @@ func (f *File) Priority() piecePriority {
 	return f.prio
 }
 
-func (f *File) firstPieceIndex() pwp.Integer {
+func (f *File) firstPieceIndex() pieceIndex {
 	if f.t.usualPieceSize() == 0 {
 		return 0
 	}
-	return pwp.Integer(f.offset / int64(f.t.usualPieceSize()))
+	return pieceIndex(f.offset / int64(f.t.usualPieceSize()))
 }
 
-func (f *File) endPieceIndex() pwp.Integer {
+func (f *File) endPieceIndex() pieceIndex {
 	if f.t.usualPieceSize() == 0 {
 		return 0
 	}
-	return pwp.Integer((f.offset+f.length-1)/int64(f.t.usualPieceSize())) + 1
+	return pieceIndex((f.offset+f.length-1)/int64(f.t.usualPieceSize())) + 1
 }

misc.go

@@ -98,7 +98,7 @@ func validateInfo(info *metainfo.Info) error {
 	return nil
 }
 
-func chunkIndexSpec(index pieceIndex, pieceLength, chunkSize pp.Integer) chunkSpec {
+func chunkIndexSpec(index pp.Integer, pieceLength, chunkSize pp.Integer) chunkSpec {
 	ret := chunkSpec{pp.Integer(index) * chunkSize, chunkSize}
 	if ret.Begin+ret.Length > pieceLength {
 		ret.Length = pieceLength - ret.Begin
@@ -154,6 +154,6 @@ func min(as ...int64) int64 {
 var unlimited = rate.NewLimiter(rate.Inf, 0)
 
 type (
-	pieceIndex = pp.Integer
+	pieceIndex = int
 	InfoHash   = metainfo.Hash
 )

reader.go

@@ -85,7 +85,7 @@ func (r *reader) readable(off int64) (ret bool) {
 	if r.responsive {
 		return r.t.haveChunk(req)
 	}
-	return r.t.pieceComplete(req.Index)
+	return r.t.pieceComplete(pieceIndex(req.Index))
 }
 
 // How many bytes are available to read. Max is the most we could require.

torrent.go

@@ -33,7 +33,7 @@ import (
 	"github.com/anacrolix/torrent/tracker"
 )
 
-func (t *Torrent) chunkIndexSpec(chunkIndex, piece pieceIndex) chunkSpec {
+func (t *Torrent) chunkIndexSpec(chunkIndex pp.Integer, piece pieceIndex) chunkSpec {
 	return chunkIndexSpec(chunkIndex, t.pieceLength(piece), t.chunkSize)
 }
 
@@ -795,7 +795,7 @@ func (t *Torrent) haveChunk(r request) (ret bool) {
 	if !t.haveInfo() {
 		return false
 	}
-	if t.pieceComplete(r.Index) {
+	if t.pieceComplete(pieceIndex(r.Index)) {
 		return true
 	}
 	p := &t.pieces[r.Index]
@@ -807,7 +807,7 @@ func chunkIndex(cs chunkSpec, chunkSize pp.Integer) int {
 }
 
 func (t *Torrent) wantPiece(r request) bool {
-	if !t.wantPieceIndex(r.Index) {
+	if !t.wantPieceIndex(pieceIndex(r.Index)) {
 		return false
 	}
 	if t.pieces[r.Index].pendingChunk(r.chunkSpec, t.chunkSize) {