Added mutex for lastPlayedCache.

internal/radio/icecast.go

@@ -7,6 +7,7 @@ import (
 	"net/http"
 	"os/exec"
 	"strings"
+	"sync"
 	"time"
 
 	"github.com/pkg/errors"
@@ -65,19 +66,27 @@ func IcecastGetStatus(icecastURL string) (*IcecastStatus, error) {
 }
 
 func IcecastLastPlayedSongs(lastNSongs int, playlistPath string) ([]Song, error) {
-	if lpcLen := len(lastPlayedCache); lpcLen > 0 {
+	{
-		if lastNSongs > lpcLen {
+		lastPlayedCacheMutex.Lock()
-			lastNSongs = lpcLen
+		defer lastPlayedCacheMutex.Unlock()
+		if lpcLen := len(lastPlayedCache); lpcLen > 0 {
+			if lastNSongs > lpcLen {
+				lastNSongs = lpcLen
+			}
+			return lastPlayedCache[lpcLen-lastNSongs:], nil
 		}
-		return lastPlayedCache[lpcLen-lastNSongs:], nil
 	}
 
 	return lastPlayedSongs(lastNSongs, playlistPath)
 }
 
 func IcecastLastSong(playlistPath string) (Song, error) {
-	if lpcLen := len(lastPlayedCache); lpcLen > 0 {
+	{
-		return lastPlayedCache[lpcLen-1], nil
+		lastPlayedCacheMutex.Lock()
+		defer lastPlayedCacheMutex.Unlock()
+		if lpcLen := len(lastPlayedCache); lpcLen > 0 {
+			return lastPlayedCache[lpcLen-1], nil
+		}
 	}
 
 	songs, err := lastPlayedSongs(1, playlistPath)
@@ -121,6 +130,7 @@ func lastPlayedSongs(lastNSongs int, playlistPath string) ([]Song, error) {
 var playlistWatcher watcher.InotifyWatcher
 var playlistFired chan uint32
 var lastPlayedCache []Song
+var lastPlayedCacheMutex sync.Mutex
 
 func IcecastWatchPlaylist(playlistPath string, lastNSongs int) error {
 	playlistWatcher, err := watcher.NewInotifyWatcher()
@@ -141,6 +151,8 @@ func IcecastWatchPlaylist(playlistPath string, lastNSongs int) error {
 		for {
 			select {
 			case <-playlistFired:
+				lastPlayedCacheMutex.Lock()
+				defer lastPlayedCacheMutex.Unlock()
 				songs, err := lastPlayedSongs(lastNSongs, playlistPath)
 				if err == nil && len(songs) > 0 {
 					lastPlayedCache = songs