Merge pull request #24418 from peppy/now-playing-async-fix

Fix now playing overlay background occasionally showing incorrect background

osu.Game/Overlays/NowPlayingOverlay.cs

@@ -1,13 +1,12 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
 using System;
-using System.Threading.Tasks;
+using System.Threading;
 using osu.Framework.Allocation;
 using osu.Framework.Bindables;
 using osu.Framework.Extensions.Color4Extensions;
+using osu.Framework.Extensions.ObjectExtensions;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Framework.Graphics.Effects;
@@ -40,33 +39,33 @@ namespace osu.Game.Overlays
         private const float bottom_black_area_height = 55;
         private const float margin = 10;
 
-        private Drawable background;
-        private ProgressBar progressBar;
+        private Drawable background = null!;
+        private ProgressBar progressBar = null!;
 
-        private IconButton prevButton;
-        private IconButton playButton;
-        private IconButton nextButton;
-        private IconButton playlistButton;
+        private IconButton prevButton = null!;
+        private IconButton playButton = null!;
+        private IconButton nextButton = null!;
+        private IconButton playlistButton = null!;
 
-        private SpriteText title, artist;
+        private SpriteText title = null!, artist = null!;
 
-        private PlaylistOverlay playlist;
+        private PlaylistOverlay? playlist;
 
-        private Container dragContainer;
-        private Container playerContainer;
-        private Container playlistContainer;
+        private Container dragContainer = null!;
+        private Container playerContainer = null!;
+        private Container playlistContainer = null!;
 
         protected override string PopInSampleName => "UI/now-playing-pop-in";
         protected override string PopOutSampleName => "UI/now-playing-pop-out";
 
         [Resolved]
-        private MusicController musicController { get; set; }
+        private MusicController musicController { get; set; } = null!;
 
         [Resolved]
-        private Bindable<WorkingBeatmap> beatmap { get; set; }
+        private Bindable<WorkingBeatmap> beatmap { get; set; } = null!;
 
         [Resolved]
-        private OsuColour colours { get; set; }
+        private OsuColour colours { get; set; } = null!;
 
         private Bindable<bool> allowTrackControl;
 
@@ -290,31 +289,34 @@ namespace osu.Game.Overlays
             }
         }
 
-        private Action pendingBeatmapSwitch;
+        private Action? pendingBeatmapSwitch;
+
+        private CancellationTokenSource? backgroundLoadCancellation;
+
+        private WorkingBeatmap? currentBeatmap;
 
         private void trackChanged(WorkingBeatmap beatmap, TrackChangeDirection direction = TrackChangeDirection.None)
         {
+            currentBeatmap = beatmap;
+
             // avoid using scheduler as our scheduler may not be run for a long time, holding references to beatmaps.
             pendingBeatmapSwitch = delegate
             {
-                // todo: this can likely be replaced with WorkingBeatmap.GetBeatmapAsync()
-                Task.Run(() =>
-                {
-                    if (beatmap?.Beatmap == null) // this is not needed if a placeholder exists
-                    {
-                        title.Text = @"Nothing to play";
-                        artist.Text = @"Nothing to play";
-                    }
-                    else
-                    {
-                        BeatmapMetadata metadata = beatmap.Metadata;
-                        title.Text = new RomanisableString(metadata.TitleUnicode, metadata.Title);
-                        artist.Text = new RomanisableString(metadata.ArtistUnicode, metadata.Artist);
-                    }
-                });
+                BeatmapMetadata metadata = beatmap.Metadata;
+
+                title.Text = new RomanisableString(metadata.TitleUnicode, metadata.Title);
+                artist.Text = new RomanisableString(metadata.ArtistUnicode, metadata.Artist);
+
+                backgroundLoadCancellation?.Cancel();
 
                 LoadComponentAsync(new Background(beatmap) { Depth = float.MaxValue }, newBackground =>
                 {
+                    if (beatmap != currentBeatmap)
+                    {
+                        newBackground.Dispose();
+                        return;
+                    }
+
                     switch (direction)
                     {
                         case TrackChangeDirection.Next:
@@ -334,7 +336,7 @@ namespace osu.Game.Overlays
                     background = newBackground;
 
                     playerContainer.Add(newBackground);
-                });
+                }, (backgroundLoadCancellation = new CancellationTokenSource()).Token);
             };
         }
 
@@ -356,7 +358,7 @@ namespace osu.Game.Overlays
         {
             base.Dispose(isDisposing);
 
-            if (musicController != null)
+            if (musicController.IsNotNull())
                 musicController.TrackChanged -= trackChanged;
         }
 
@@ -389,7 +391,7 @@ namespace osu.Game.Overlays
             private readonly Sprite sprite;
             private readonly WorkingBeatmap beatmap;
 
-            public Background(WorkingBeatmap beatmap = null)
+            public Background(WorkingBeatmap beatmap)
                 : base(cachedFrameBuffer: true)
             {
                 this.beatmap = beatmap;
@@ -419,7 +421,7 @@ namespace osu.Game.Overlays
             [BackgroundDependencyLoader]
             private void load(LargeTextureStore textures)
             {
-                sprite.Texture = beatmap?.GetBackground() ?? textures.Get(@"Backgrounds/bg4");
+                sprite.Texture = beatmap.GetBackground() ?? textures.Get(@"Backgrounds/bg4");
             }
         }