From 5b9d906ad510137956e6e29c69e5fa2d976714a6 Mon Sep 17 00:00:00 2001
From: Dean Herbert <pe@ppy.sh>
Date: Tue, 12 Sep 2017 16:55:48 +0900
Subject: [PATCH] Improve beatmap track disposal logic

- [ ] Depends on https://github.com/ppy/osu-framework/pull/1035
---
 osu.Game/Beatmaps/WorkingBeatmap.cs | 11 +++++++++--
 osu.Game/OsuGameBase.cs             | 13 +++++++++++--
 2 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/osu.Game/Beatmaps/WorkingBeatmap.cs b/osu.Game/Beatmaps/WorkingBeatmap.cs
index e6a26baa66..df8e7f5e3b 100644
--- a/osu.Game/Beatmaps/WorkingBeatmap.cs
+++ b/osu.Game/Beatmaps/WorkingBeatmap.cs
@@ -109,10 +109,17 @@ public void TransferTo(WorkingBeatmap other)
 
         public virtual void Dispose()
         {
-            track?.Dispose();
-            track = null;
             background?.Dispose();
             background = null;
         }
+
+        public void DisposeTrack()
+        {
+            lock (trackLock)
+            {
+                track?.Dispose();
+                track = null;
+            }
+        }
     }
 }
diff --git a/osu.Game/OsuGameBase.cs b/osu.Game/OsuGameBase.cs
index 76eb7d5101..d81c7cdf73 100644
--- a/osu.Game/OsuGameBase.cs
+++ b/osu.Game/OsuGameBase.cs
@@ -152,10 +152,19 @@ private void load()
 
             Beatmap.ValueChanged += b =>
             {
+                var trackLoaded = lastBeatmap?.TrackLoaded ?? false;
+
                 // compare to last beatmap as sometimes the two may share a track representation (optimisation, see WorkingBeatmap.TransferTo)
-                if (lastBeatmap?.Track != b.Track)
+                if (!trackLoaded || lastBeatmap?.Track != b.Track)
                 {
-                    lastBeatmap?.Track?.Dispose();
+                    if (trackLoaded)
+                    {
+                        Debug.Assert(lastBeatmap != null);
+                        Debug.Assert(lastBeatmap.Track != null);
+
+                        lastBeatmap.DisposeTrack();
+                    }
+
                     Audio.Track.AddItem(b.Track);
                 }