Set priorities ahead of the current read position

client.go

@@ -264,22 +264,36 @@ func (cl *Client) torrentReadAt(t *torrent, off int64, p []byte) (n int, err err
 		err = io.EOF
 		return
 	}
+	cl.readRaisePiecePriorities(t, off, int64(len(p)))
 	if len(p) > pieceLeft {
 		p = p[:pieceLeft]
 	}
 	if len(p) == 0 {
 		panic(len(p))
 	}
-	cl.prioritizePiece(t, index, piecePriorityHigh)
-	for i := index + 1; i < index+7 && i < t.NumPieces(); i++ {
-		cl.prioritizePiece(t, i, piecePriorityNormal)
-	}
 	for !piece.Complete() {
 		piece.Event.Wait()
 	}
 	return t.Data.ReadAt(p, off)
 }
 
+func (cl *Client) readRaisePiecePriorities(t *torrent, off, _len int64) {
+	index := int(off / int64(t.UsualPieceSize()))
+	cl.raisePiecePriority(t, index, piecePriorityNow)
+	index++
+	if index >= t.NumPieces() {
+		return
+	}
+	cl.raisePiecePriority(t, index, piecePriorityNext)
+	for i := 0; i < 5; i++ {
+		index++
+		if index >= t.NumPieces() {
+			break
+		}
+		cl.raisePiecePriority(t, index, piecePriorityReadahead)
+	}
+}
+
 func (cl *Client) configDir() string {
 	return filepath.Join(os.Getenv("HOME"), ".config/torrent")
 }
@@ -292,6 +306,12 @@ func (t *torrent) connPendPiece(c *connection, piece int) {
 	c.pendPiece(piece, t.Pieces[piece].Priority)
 }
 
+func (cl *Client) raisePiecePriority(t *torrent, piece int, priority piecePriority) {
+	if t.Pieces[piece].Priority < priority {
+		cl.prioritizePiece(t, piece, priority)
+	}
+}
+
 func (cl *Client) prioritizePiece(t *torrent, piece int, priority piecePriority) {
 	if t.havePiece(piece) {
 		return
@@ -1595,8 +1615,10 @@ func (t Torrent) DownloadAll() {
 		// TODO: Leave higher priorities as they were?
 		t.cl.prioritizePiece(t.torrent, i, piecePriorityNormal)
 	}
-	t.cl.prioritizePiece(t.torrent, 0, piecePriorityHigh)
-	t.cl.prioritizePiece(t.torrent, t.NumPieces()-1, piecePriorityHigh)
+	// Nice to have the first and last pieces soon for various interactive
+	// purposes.
+	t.cl.prioritizePiece(t.torrent, 0, piecePriorityReadahead)
+	t.cl.prioritizePiece(t.torrent, t.NumPieces()-1, piecePriorityReadahead)
 	t.cl.mu.Unlock()
 }
 

connection.go

@@ -8,7 +8,6 @@ import (
 	"expvar"
 	"fmt"
 	"io"
-	"log"
 	"net"
 	"sync"
 	"time"
@@ -94,11 +93,15 @@ func (cn *connection) pendPiece(piece int, priority piecePriority) {
 		return
 	}
 	key := cn.piecePriorities[piece]
-	if priority == piecePriorityHigh {
-		key = -key
-	}
-	if piece == 0 {
-		log.Print(key)
+	// TODO: Have some kind of overlap here, so there's some probabilistic
+	// favouring of higher priority pieces.
+	switch priority {
+	case piecePriorityReadahead:
+		key -= len(cn.piecePriorities)
+	case piecePriorityNext:
+		key -= 2 * len(cn.piecePriorities)
+	case piecePriorityNow:
+		key -= 3 * len(cn.piecePriorities)
 	}
 	cn.pieceRequestOrder.SetPiece(piece, key)
 }

misc.go

@@ -43,7 +43,9 @@ type piecePriority byte
 const (
 	piecePriorityNone piecePriority = iota
 	piecePriorityNormal
-	piecePriorityHigh
+	piecePriorityReadahead
+	piecePriorityNext
+	piecePriorityNow
 )
 
 type piece struct {

torrent.go

@@ -281,12 +281,26 @@ func (t *torrent) pieceStatusChar(index int) byte {
 		return 'H'
 	case !p.EverHashed:
 		return '?'
-	case p.Priority == piecePriorityHigh:
-		return '!'
 	case t.PiecePartiallyDownloaded(index):
-		return 'P'
+		switch p.Priority {
+		case piecePriorityNone:
+			return 'F' // Forgotten
+		default:
+			return 'P'
+		}
 	default:
-		return '.'
+		switch p.Priority {
+		case piecePriorityNone:
+			return 'z'
+		case piecePriorityNow:
+			return '!'
+		case piecePriorityReadahead:
+			return 'R'
+		case piecePriorityNext:
+			return 'N'
+		default:
+			return '.'
+		}
 	}
 }