In Playlist embed a sync.Mutex instead.

internal/radio/playlist.go

@@ -11,7 +11,7 @@ import (
 
 // Playlist holds a list of paths to a song files.
 type Playlist struct {
-	mut      sync.Mutex
+	sync.Mutex
 	filePath string
 	playlist []string
 	cur      int
@@ -30,8 +30,8 @@ func NewPlaylist(filePath string, repeat bool) (*Playlist, error) {
 // Next returns the next song to play. Returns an empty string if repeat is
 // false and the end of a playlist was reached.
 func (p *Playlist) Next() (song string) {
-	p.mut.Lock()
-	defer p.mut.Unlock()
+	p.Lock()
+	defer p.Unlock()
 	if p.cur == len(p.playlist) {
 		// If the end of a playlist was reached and repeat is set to true,
 		// then go back to the head of it, thus repeating it. Return an empty
@@ -53,10 +53,10 @@ func (p *Playlist) load() error {
 	if err != nil {
 		return err
 	}
-	p.mut.Lock()
+	p.Lock()
 	p.playlist = strings.Split(string(data), "\n")
 	p.cur = 0
-	p.mut.Unlock()
+	p.Unlock()
 	return nil
 }