Added max queue length config entry

config.go

@@ -15,6 +15,7 @@ type Config struct {
 		BufferLengthInKiB int    `toml:"buffer_len"`
 		BufferSeconds     int    `toml:"buffer_size"`
 		ReplayGain        bool   `toml:"replaygain"`
+		Length            int    `toml:"length"`
 	} `toml:"queue"`
 	Radio struct {
 		Port        int    `toml:"port"`

queue.go

@@ -249,6 +249,10 @@ func (q *Queue) AddTrack(entry *QueueTrackEntry, tail bool) error {
 	q.mutex.Lock()
 	defer q.mutex.Unlock()
 
+	if q.config.Queue.Length > 0 && len(q.queue) >= q.config.Queue.Length {
+		return errors.New("queue too long")
+	}
+
 	source := entry.source
 	if q.config.Queue.ReplayGain {
 		if entry.Metadata.ReplayGain.TrackPeak != 0 {