Introduce PreviewTrack class

osu.Game/Audio/PreviewTrack.cs

@@ -0,0 +1,39 @@
+// Copyright (c) 2007-2018 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using System;
+using osu.Framework.Audio.Track;
+
+namespace osu.Game.Audio
+{
+    public class PreviewTrack
+    {
+        public readonly Track Track;
+        private readonly Action<PreviewTrack> onStart;
+        private readonly Action onStop;
+
+        public event Action Stopped;
+        public event Action Started;
+
+        public PreviewTrack(Track track, Action<PreviewTrack> onStart, Action onStop)
+        {
+            Track = track;
+            this.onStart = onStart;
+            this.onStop = onStop;
+        }
+
+        public void Start()
+        {
+            onStart?.Invoke(this);
+            Track.Restart();
+            Started?.Invoke();
+        }
+
+        public void Stop()
+        {
+            onStop?.Invoke();
+            Track.Stop();
+            Stopped?.Invoke();
+        }
+    }
+}

osu.Game/Audio/PreviewTrackManager.cs

@@ -14,13 +14,13 @@ namespace osu.Game.Audio
 {
     public class PreviewTrackManager : Component
     {
-        public event Action PlaybackStarted;
+        private Action<PreviewTrack> onTrackStart;
-        public event Action PlaybackStopped;
+        private Action onTrackStop;
 
         private TrackManager trackManager;
         private BindableDouble muteBindable;
 
-        public Track CurrentTrack { get; private set; }
+        public PreviewTrack CurrentTrack { get; private set; }
 
         [BackgroundDependencyLoader]
         private void load(AudioManager audio, FrameworkConfigManager config)
@@ -32,35 +32,28 @@ namespace osu.Game.Audio
             audio.AddItem(trackManager);
             config.BindWith(FrameworkSetting.VolumeMusic, trackManager.Volume);
 
-            PlaybackStarted += () => audio.Track.AddAdjustment(AdjustableProperty.Volume, muteBindable);
+            onTrackStart = track =>
-            PlaybackStopped += () => audio.Track.RemoveAdjustment(AdjustableProperty.Volume, muteBindable);
+            {
+                CurrentTrack?.Stop();
+                audio.Track.AddAdjustment(AdjustableProperty.Volume, muteBindable);
+                CurrentTrack = track;
+                CurrentTrack.Stopped += () => CurrentTrack = null;
+            };
+            onTrackStop = () => audio.Track.RemoveAdjustment(AdjustableProperty.Volume, muteBindable);
         }
 
-        public Track Get(BeatmapSetInfo beatmapSetInfo) => trackManager.Get($"https://b.ppy.sh/preview/{beatmapSetInfo.OnlineBeatmapSetID}.mp3");
+        public PreviewTrack Get(BeatmapSetInfo beatmapSetInfo) =>
+            new PreviewTrack(
+                trackManager.Get($"https://b.ppy.sh/preview/{beatmapSetInfo.OnlineBeatmapSetID}.mp3"),
+                onTrackStart,
+                onTrackStop);
 
         protected override void Update()
         {
-            if (CurrentTrack?.HasCompleted ?? false)
+            if (CurrentTrack?.Track.HasCompleted ?? false)
-                PlaybackStopped?.Invoke();
+                CurrentTrack.Stop();
 
             base.Update();
         }
-
-        public void Play(Track track)
-        {
-            Stop();
-            CurrentTrack = track;
-            track.Restart();
-            PlaybackStarted?.Invoke();
-        }
-
-        public void Stop()
-        {
-            if (CurrentTrack?.IsRunning ?? false)
-            {
-                CurrentTrack?.Stop();
-                PlaybackStopped?.Invoke();
-            }
-        }
     }
 }

osu.Game/Overlays/BeatmapSet/Buttons/PreviewButton.cs

@@ -2,13 +2,13 @@
 // Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
 
 using osu.Framework.Allocation;
-using osu.Framework.Audio.Track;
 using osu.Framework.Configuration;
 using osu.Framework.Extensions.Color4Extensions;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Framework.Graphics.Shapes;
 using osu.Framework.Input;
+using osu.Game.Audio;
 using osu.Game.Beatmaps;
 using osu.Game.Graphics;
 using osu.Game.Graphics.Containers;
@@ -25,7 +25,7 @@ namespace osu.Game.Overlays.BeatmapSet.Buttons
         private readonly Box bg, progress;
         private readonly PlayButton playButton;
 
-        private Track preview => playButton.Preview;
+        private PreviewTrack preview => playButton.Preview;
         public Bindable<bool> Playing => playButton.Playing;
 
         public BeatmapSetInfo BeatmapSet
@@ -83,7 +83,7 @@ namespace osu.Game.Overlays.BeatmapSet.Buttons
             if (Playing.Value && preview != null)
             {
                 // prevent negative (potential infinite) width if a track without length was loaded
-                progress.Width = preview.Length > 0 ? (float)(preview.CurrentTime / preview.Length) : 0f;
+                progress.Width = preview.Track.Length > 0 ? (float)(preview.Track.CurrentTime / preview.Track.Length) : 0f;
             }
             else
                 progress.Width = 0;

osu.Game/Overlays/Direct/DirectPanel.cs

@@ -4,22 +4,22 @@
 using System.Collections.Generic;
 using System.Linq;
 using osu.Framework.Allocation;
+using osu.Framework.Configuration;
 using osu.Framework.Extensions.Color4Extensions;
-using OpenTK;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Framework.Graphics.Shapes;
 using osu.Framework.Graphics.Sprites;
+using osu.Framework.Input;
+using osu.Game.Audio;
 using osu.Game.Beatmaps;
 using osu.Game.Beatmaps.Drawables;
 using osu.Game.Graphics;
 using osu.Game.Graphics.Sprites;
-using OpenTK.Graphics;
-using osu.Framework.Input;
 using osu.Game.Graphics.UserInterface;
 using osu.Game.Online.API.Requests;
-using osu.Framework.Configuration;
+using OpenTK;
-using osu.Framework.Audio.Track;
+using OpenTK.Graphics;
 
 namespace osu.Game.Overlays.Direct
 {
@@ -37,7 +37,7 @@ namespace osu.Game.Overlays.Direct
         private BeatmapManager beatmaps;
         private BeatmapSetOverlay beatmapSetOverlay;
 
-        public Track Preview => PlayButton.Preview;
+        public PreviewTrack Preview => PlayButton.Preview;
         public Bindable<bool> PreviewPlaying => PlayButton.Playing;
         protected abstract PlayButton PlayButton { get; }
         protected abstract Box PreviewBar { get; }
@@ -121,9 +121,9 @@ namespace osu.Game.Overlays.Direct
         {
             base.Update();
 
-            if (PreviewPlaying && Preview != null && Preview.IsLoaded)
+            if (PreviewPlaying && Preview != null && Preview.Track.IsLoaded)
             {
-                PreviewBar.Width = (float)(Preview.CurrentTime / Preview.Length);
+                PreviewBar.Width = (float)(Preview.Track.CurrentTime / Preview.Track.Length);
             }
         }
 

osu.Game/Overlays/Direct/PlayButton.cs

@@ -3,7 +3,6 @@
 
 using System.Threading.Tasks;
 using osu.Framework.Allocation;
-using osu.Framework.Audio.Track;
 using osu.Framework.Configuration;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
@@ -19,7 +18,7 @@ namespace osu.Game.Overlays.Direct
     public class PlayButton : Container
     {
         public readonly Bindable<bool> Playing = new Bindable<bool>();
-        public Track Preview { get; private set; }
+        public PreviewTrack Preview { get; private set; }
 
         private BeatmapSetInfo beatmapSet;
 
@@ -32,6 +31,8 @@ namespace osu.Game.Overlays.Direct
                 beatmapSet = value;
 
                 Playing.Value = false;
+                if (Preview != null)
+                    Preview.Stopped -= preview_Stopped;
                 Preview = null;
             }
         }
@@ -85,12 +86,6 @@ namespace osu.Game.Overlays.Direct
         {
             hoverColour = colour.Yellow;
             this.previewTrackManager = previewTrackManager;
-
-            previewTrackManager.PlaybackStopped += () =>
-            {
-                if (Preview == previewTrackManager.CurrentTrack)
-                    Playing.Value = false;
-            };
         }
 
         protected override bool OnClick(InputState state)
@@ -134,21 +129,24 @@ namespace osu.Game.Overlays.Direct
                         })
                         .ContinueWith(t =>
                         {
+                            Preview.Stopped += preview_Stopped;
                             playingStateChanged(true);
                             loading = false;
                         });
                     return;
                 }
 
-                previewTrackManager.Play(Preview);
+                Preview.Start();
             }
             else
             {
-                previewTrackManager.Stop();
+                Preview.Stop();
                 loading = false;
             }
         }
 
+        private void preview_Stopped() => Playing.Value = false;
+
         protected override void Dispose(bool isDisposing)
         {
             base.Dispose(isDisposing);