Rewrite waveform invalidation

osu.Game/Beatmaps/WorkingBeatmap.cs

@@ -34,8 +34,6 @@ public abstract class WorkingBeatmap : IWorkingBeatmap
         // TODO: remove once the fallback lookup is not required (and access via `working.BeatmapInfo.Metadata` directly).
         public BeatmapMetadata Metadata => BeatmapInfo.Metadata;
 
-        public Waveform Waveform => waveform.Value;
-
         public Storyboard Storyboard => storyboard.Value;
 
         public Texture Background => GetBackground(); // Texture uses ref counting, so we want to return a new instance every usage.
@@ -48,7 +46,7 @@ public abstract class WorkingBeatmap : IWorkingBeatmap
 
         private readonly object beatmapFetchLock = new object();
 
-        private Lazy<Waveform> waveform;
+        private Waveform waveform;
         private readonly Lazy<Storyboard> storyboard;
         private readonly Lazy<ISkin> skin;
         private Track track; // track is not Lazy as we allow transferring and loading multiple times.
@@ -60,7 +58,6 @@ protected WorkingBeatmap(BeatmapInfo beatmapInfo, AudioManager audioManager)
             BeatmapInfo = beatmapInfo;
             BeatmapSetInfo = beatmapInfo.BeatmapSet ?? new BeatmapSetInfo();
 
-            waveform = new Lazy<Waveform>(GetWaveform);
             storyboard = new Lazy<Storyboard>(GetStoryboard);
             skin = new Lazy<ISkin>(GetSkin);
         }
@@ -171,6 +168,18 @@ protected Track GetVirtualTrack(double emptyLength = 0)
 
         #endregion
 
+        #region Waveform
+
+        public Waveform Waveform => waveform ??= GetWaveform();
+
+        /// <summary>
+        /// Reloads waveform of beatmap's track even if one is already cached.
+        /// </summary>
+        /// <returns>Newly loaded waveform.</returns>
+        public Waveform LoadWaveform() => waveform = GetWaveform();
+
+        #endregion
+
         #region Beatmap
 
         public virtual bool BeatmapLoaded => beatmapLoadTask?.IsCompleted ?? false;
@@ -329,12 +338,6 @@ public virtual IBeatmap GetPlayableBeatmap(IRulesetInfo ruleset, IReadOnlyList<M
 
         #endregion
 
-        public void InvalidateWaveform()
-        {
-            if (waveform.IsValueCreated)
-                waveform = new Lazy<Waveform>(GetWaveform);
-        }
-
         public override string ToString() => BeatmapInfo.ToString();
 
         public abstract Stream GetStream(string storagePath);

osu.Game/Screens/Edit/Setup/ResourcesSection.cs

@@ -118,7 +118,7 @@ public bool ChangeAudioTrack(FileInfo source)
             }
 
             working.Value.Metadata.AudioFile = destination.Name;
-            working.Value.InvalidateWaveform();
+            working.Value.LoadWaveform();
             editorBeatmap.SaveState();
             music.ReloadCurrentTrack();