feat: perform prefetch synchronously with main loop

Fixes #79

Author: devgianlu

cmd/daemon/controls.go

@@ -20,8 +20,10 @@ import (
 	"google.golang.org/protobuf/proto"
 )
 
-func (p *AppPlayer) prefetchNext() {
-	ctx := context.TODO()
+func (p *AppPlayer) prefetchNext(ctx context.Context) {
+	// Limit ourselves to 30 seconds for prefetching
+	ctx, cancel := context.WithTimeout(ctx, 30*time.Second)
+	defer cancel()
 
 	next := p.state.tracks.PeekNext(ctx)
 	if next == nil {
@@ -61,16 +63,15 @@ func (p *AppPlayer) prefetchNext() {
 
 func (p *AppPlayer) schedulePrefetchNext() {
 	if p.state.player.IsPaused || p.primaryStream == nil {
-		p.prefetchTimer.Reset(time.Duration(math.MaxInt64))
+		p.prefetchTimer.Stop()
 		return
 	}
 
 	untilTrackEnd := time.Duration(p.primaryStream.Media.Duration()-int32(p.player.PositionMs())) * time.Millisecond
 	untilTrackEnd -= 30 * time.Second
 	if untilTrackEnd < 10*time.Second {
-		p.prefetchTimer.Reset(time.Duration(math.MaxInt64))
-
-		go p.prefetchNext()
+		p.prefetchTimer.Reset(0)
+		p.app.log.Tracef("prefetch as soon as possible")
 	} else {
 		p.prefetchTimer.Reset(untilTrackEnd)
 		p.app.log.Tracef("scheduling prefetch in %.0fs", untilTrackEnd.Seconds())

cmd/daemon/main.go

@@ -122,8 +122,8 @@ func (app *App) newAppPlayer(ctx context.Context, creds any) (_ *AppPlayer, err
 		volumeUpdate: make(chan float32, 1),
 	}
 
-	// start a dummy timer for prefetching next media
-	appPlayer.prefetchTimer = time.AfterFunc(time.Duration(math.MaxInt64), appPlayer.prefetchNext)
+	appPlayer.prefetchTimer = time.NewTimer(math.MaxInt64)
+	appPlayer.prefetchTimer.Stop()
 
 	if appPlayer.sess, err = session.NewSessionFromOptions(ctx, &session.Options{
 		Log:         app.log,

cmd/daemon/player.go

@@ -718,6 +718,8 @@ func (p *AppPlayer) Run(ctx context.Context, apiRecv <-chan ApiRequest, mprisRec
 			}
 
 			p.handlePlayerEvent(ctx, &ev)
+		case <-p.prefetchTimer.C:
+			p.prefetchNext(ctx)
 		case volume := <-p.volumeUpdate:
 			// Received a new volume: from Spotify Connect, from the REST API,
 			// or from the system volume mixer.