From a28e71995d818c500c043fc5b83253d5ae57520f Mon Sep 17 00:00:00 2001
From: Dean Herbert <pe@ppy.sh>
Date: Wed, 30 May 2018 16:15:00 +0900
Subject: [PATCH] Offload database query to task

Allows song select to load a touch faster, in theory.
---
 osu.Game/Beatmaps/BeatmapManager.cs   | 8 +++++++-
 osu.Game/Screens/Select/SongSelect.cs | 9 +--------
 2 files changed, 8 insertions(+), 9 deletions(-)

diff --git a/osu.Game/Beatmaps/BeatmapManager.cs b/osu.Game/Beatmaps/BeatmapManager.cs
index 36fde8a319..83f3fe7a35 100644
--- a/osu.Game/Beatmaps/BeatmapManager.cs
+++ b/osu.Game/Beatmaps/BeatmapManager.cs
@@ -241,7 +241,13 @@ public WorkingBeatmap GetWorkingBeatmap(BeatmapInfo beatmapInfo, WorkingBeatmap
         /// Returns a list of all usable <see cref="BeatmapSetInfo"/>s.
         /// </summary>
         /// <returns>A list of available <see cref="BeatmapSetInfo"/>.</returns>
-        public List<BeatmapSetInfo> GetAllUsableBeatmapSets() => beatmaps.ConsumableItems.Where(s => !s.DeletePending && !s.Protected).ToList();
+        public List<BeatmapSetInfo> GetAllUsableBeatmapSets() => GetAllUsableBeatmapSetsEnumerable().ToList();
+
+        /// <summary>
+        /// Returns a list of all usable <see cref="BeatmapSetInfo"/>s.
+        /// </summary>
+        /// <returns>A list of available <see cref="BeatmapSetInfo"/>.</returns>
+        public IQueryable<BeatmapSetInfo> GetAllUsableBeatmapSetsEnumerable() => beatmaps.ConsumableItems.Where(s => !s.DeletePending && !s.Protected);
 
         /// <summary>
         /// Perform a lookup query on available <see cref="BeatmapSetInfo"/>s.
diff --git a/osu.Game/Screens/Select/SongSelect.cs b/osu.Game/Screens/Select/SongSelect.cs
index 4ffa9e2a90..41aba9a126 100644
--- a/osu.Game/Screens/Select/SongSelect.cs
+++ b/osu.Game/Screens/Select/SongSelect.cs
@@ -2,7 +2,6 @@
 // Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
 
 using System;
-using System.Threading;
 using OpenTK;
 using OpenTK.Input;
 using osu.Framework.Allocation;
@@ -63,8 +62,6 @@ public abstract class SongSelect : OsuScreen
         private SampleChannel sampleChangeDifficulty;
         private SampleChannel sampleChangeBeatmap;
 
-        private CancellationTokenSource initialAddSetsTask;
-
         private DependencyContainer dependencies;
         protected override IReadOnlyDependencyContainer CreateLocalDependencies(IReadOnlyDependencyContainer parent) => dependencies = new DependencyContainer(parent);
 
@@ -207,9 +204,7 @@ private void load(BeatmapManager beatmaps, AudioManager audio, DialogOverlay dia
             sampleChangeDifficulty = audio.Sample.Get(@"SongSelect/select-difficulty");
             sampleChangeBeatmap = audio.Sample.Get(@"SongSelect/select-expand");
 
-            initialAddSetsTask = new CancellationTokenSource();
-
-            Carousel.BeatmapSets = this.beatmaps.GetAllUsableBeatmapSets();
+            Carousel.BeatmapSets = this.beatmaps.GetAllUsableBeatmapSetsEnumerable();
 
             Beatmap.DisabledChanged += disabled => Carousel.AllowSelection = !disabled;
             Beatmap.TriggerChange();
@@ -417,8 +412,6 @@ protected override void Dispose(bool isDisposing)
                 beatmaps.BeatmapHidden -= onBeatmapHidden;
                 beatmaps.BeatmapRestored -= onBeatmapRestored;
             }
-
-            initialAddSetsTask?.Cancel();
         }
 
         /// <summary>