Fix Memory Leaks

OpenUtau.Core/Classic/ClassicSinger.cs

@@ -10,7 +10,7 @@
 using WanaKanaNet;
 
 namespace OpenUtau.Classic {
-    public class ClassicSinger : USinger {
+    public class ClassicSinger : USinger, IDisposable {
         public override string Id => voicebank.Id;
         public override string Name => voicebank.Name;
         public override Dictionary<string, string> LocalizedNames => voicebank.LocalizedNames;
@@ -160,6 +160,11 @@ public override void Save() {
                 otoWatcher.Paused = false;
             }
         }
+
+        public void Dispose() {
+            otoWatcher?.Dispose();
+            otoWatcher = null;
+        }
 
         public override bool TryGetOto(string phoneme, out UOto oto) {
             if (otoMap.TryGetValue(phoneme, out oto)) {

OpenUtau.Core/SingerManager.cs

@@ -29,6 +29,7 @@ public void SearchAllSingers() {
             Log.Information("Searching singers.");
             Directory.CreateDirectory(PathManager.Inst.SingersPath);
             var stopWatch = Stopwatch.StartNew();
+            var oldSingers = Singers.Values.ToList();
             var singers = ClassicSingerLoader.FindAllSingers()
                 .Concat(Vogen.VogenSingerLoader.FindAllSingers())
                 .Distinct();
@@ -38,6 +39,9 @@ public void SearchAllSingers() {
             SingerGroups = singers
                 .GroupBy(s => s.SingerType)
                 .ToDictionary(s => s.Key, s => s.LocalizedOrderBy(singer => singer.LocalizedName).ToList());
+            foreach (var old in oldSingers) {
+                (old as IDisposable)?.Dispose();
+            }
             stopWatch.Stop();
             Log.Information($"Search all singers: {stopWatch.Elapsed}");
         }

OpenUtau/ViewModels/TrackHeaderViewModel.cs

@@ -466,6 +466,7 @@ public void RefreshRenderers() {
 
         public void RefreshAvatar() {
             var singer = track?.Singer;
+            Avatar?.Dispose();
             if (singer == null || singer.AvatarData == null) {
                 Avatar = new RenderTargetBitmap(new PixelSize(1, 1));
                 return;