Merge branch 'master' into fix-gamehost-tests

osu.Android.props

@@ -52,7 +52,7 @@
   </ItemGroup>
   <ItemGroup>
     <PackageReference Include="ppy.osu.Game.Resources" Version="2021.1004.0" />
-    <PackageReference Include="ppy.osu.Framework.Android" Version="2021.1004.0" />
+    <PackageReference Include="ppy.osu.Framework.Android" Version="2021.1012.0" />
   </ItemGroup>
   <ItemGroup Label="Transitive Dependencies">
     <!-- Realm needs to be directly referenced in all Xamarin projects, as it will not pull in its transitive dependencies otherwise. -->

osu.Game.Tests/Database/FileStoreTests.cs

@@ -0,0 +1,114 @@
+// 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.
+
+using System.Diagnostics;
+using System.IO;
+using System.Linq;
+using NUnit.Framework;
+using osu.Framework.Logging;
+using osu.Game.Models;
+using osu.Game.Stores;
+
+#nullable enable
+
+namespace osu.Game.Tests.Database
+{
+    public class FileStoreTests : RealmTest
+    {
+        [Test]
+        public void TestImportFile()
+        {
+            RunTestWithRealm((realmFactory, storage) =>
+            {
+                var realm = realmFactory.Context;
+                var files = new RealmFileStore(realmFactory, storage);
+
+                var testData = new MemoryStream(new byte[] { 0, 1, 2, 3 });
+
+                realm.Write(() => files.Add(testData, realm));
+
+                Assert.True(files.Storage.Exists("0/05/054edec1d0211f624fed0cbca9d4f9400b0e491c43742af2c5b0abebf0c990d8"));
+                Assert.True(files.Storage.Exists(realm.All<RealmFile>().First().StoragePath));
+            });
+        }
+
+        [Test]
+        public void TestImportSameFileTwice()
+        {
+            RunTestWithRealm((realmFactory, storage) =>
+            {
+                var realm = realmFactory.Context;
+                var files = new RealmFileStore(realmFactory, storage);
+
+                var testData = new MemoryStream(new byte[] { 0, 1, 2, 3 });
+
+                realm.Write(() => files.Add(testData, realm));
+                realm.Write(() => files.Add(testData, realm));
+
+                Assert.AreEqual(1, realm.All<RealmFile>().Count());
+            });
+        }
+
+        [Test]
+        public void TestDontPurgeReferenced()
+        {
+            RunTestWithRealm((realmFactory, storage) =>
+            {
+                var realm = realmFactory.Context;
+                var files = new RealmFileStore(realmFactory, storage);
+
+                var file = realm.Write(() => files.Add(new MemoryStream(new byte[] { 0, 1, 2, 3 }), realm));
+
+                var timer = new Stopwatch();
+                timer.Start();
+
+                realm.Write(() =>
+                {
+                    // attach the file to an arbitrary beatmap
+                    var beatmapSet = CreateBeatmapSet(CreateRuleset());
+
+                    beatmapSet.Files.Add(new RealmNamedFileUsage(file, "arbitrary.resource"));
+
+                    realm.Add(beatmapSet);
+                });
+
+                Logger.Log($"Import complete at {timer.ElapsedMilliseconds}");
+
+                string path = file.StoragePath;
+
+                Assert.True(realm.All<RealmFile>().Any());
+                Assert.True(files.Storage.Exists(path));
+
+                files.Cleanup();
+                Logger.Log($"Cleanup complete at {timer.ElapsedMilliseconds}");
+
+                Assert.True(realm.All<RealmFile>().Any());
+                Assert.True(file.IsValid);
+                Assert.True(files.Storage.Exists(path));
+            });
+        }
+
+        [Test]
+        public void TestPurgeUnreferenced()
+        {
+            RunTestWithRealm((realmFactory, storage) =>
+            {
+                var realm = realmFactory.Context;
+                var files = new RealmFileStore(realmFactory, storage);
+
+                var file = realm.Write(() => files.Add(new MemoryStream(new byte[] { 0, 1, 2, 3 }), realm));
+
+                string path = file.StoragePath;
+
+                Assert.True(realm.All<RealmFile>().Any());
+                Assert.True(files.Storage.Exists(path));
+
+                files.Cleanup();
+
+                Assert.False(realm.All<RealmFile>().Any());
+                Assert.False(file.IsValid);
+                Assert.False(files.Storage.Exists(path));
+            });
+        }
+    }
+}

osu.Game.Tests/Database/GeneralUsageTests.cs

@@ -1,3 +1,6 @@
+// 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.
+
 using System;
 using System.Threading;
 using System.Threading.Tasks;

osu.Game.Tests/Database/RealmLiveTests.cs

@@ -0,0 +1,213 @@
+// 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.
+
+using System;
+using System.Diagnostics;
+using System.Linq;
+using System.Threading.Tasks;
+using NUnit.Framework;
+using osu.Game.Beatmaps;
+using osu.Game.Database;
+using osu.Game.Models;
+using Realms;
+
+#nullable enable
+
+namespace osu.Game.Tests.Database
+{
+    public class RealmLiveTests : RealmTest
+    {
+        [Test]
+        public void TestLiveCastability()
+        {
+            RunTestWithRealm((realmFactory, _) =>
+            {
+                RealmLive<RealmBeatmap> beatmap = realmFactory.CreateContext().Write(r => r.Add(new RealmBeatmap(CreateRuleset(), new RealmBeatmapDifficulty(), new RealmBeatmapMetadata()))).ToLive();
+
+                ILive<IBeatmapInfo> iBeatmap = beatmap;
+
+                Assert.AreEqual(0, iBeatmap.Value.Length);
+            });
+        }
+
+        [Test]
+        public void TestValueAccessWithOpenContext()
+        {
+            RunTestWithRealm((realmFactory, _) =>
+            {
+                RealmLive<RealmBeatmap>? liveBeatmap = null;
+                Task.Factory.StartNew(() =>
+                {
+                    using (var threadContext = realmFactory.CreateContext())
+                    {
+                        var beatmap = threadContext.Write(r => r.Add(new RealmBeatmap(CreateRuleset(), new RealmBeatmapDifficulty(), new RealmBeatmapMetadata())));
+
+                        liveBeatmap = beatmap.ToLive();
+                    }
+                }, TaskCreationOptions.LongRunning | TaskCreationOptions.HideScheduler).Wait();
+
+                Debug.Assert(liveBeatmap != null);
+
+                Task.Factory.StartNew(() =>
+                {
+                    Assert.DoesNotThrow(() =>
+                    {
+                        using (realmFactory.CreateContext())
+                        {
+                            var resolved = liveBeatmap.Value;
+
+                            Assert.IsTrue(resolved.Realm.IsClosed);
+                            Assert.IsTrue(resolved.IsValid);
+
+                            // can access properties without a crash.
+                            Assert.IsFalse(resolved.Hidden);
+                        }
+                    });
+                }, TaskCreationOptions.LongRunning | TaskCreationOptions.HideScheduler).Wait();
+            });
+        }
+
+        [Test]
+        public void TestScopedReadWithoutContext()
+        {
+            RunTestWithRealm((realmFactory, _) =>
+            {
+                RealmLive<RealmBeatmap>? liveBeatmap = null;
+                Task.Factory.StartNew(() =>
+                {
+                    using (var threadContext = realmFactory.CreateContext())
+                    {
+                        var beatmap = threadContext.Write(r => r.Add(new RealmBeatmap(CreateRuleset(), new RealmBeatmapDifficulty(), new RealmBeatmapMetadata())));
+
+                        liveBeatmap = beatmap.ToLive();
+                    }
+                }, TaskCreationOptions.LongRunning | TaskCreationOptions.HideScheduler).Wait();
+
+                Debug.Assert(liveBeatmap != null);
+
+                Task.Factory.StartNew(() =>
+                {
+                    liveBeatmap.PerformRead(beatmap =>
+                    {
+                        Assert.IsTrue(beatmap.IsValid);
+                        Assert.IsFalse(beatmap.Hidden);
+                    });
+                }, TaskCreationOptions.LongRunning | TaskCreationOptions.HideScheduler).Wait();
+            });
+        }
+
+        [Test]
+        public void TestScopedWriteWithoutContext()
+        {
+            RunTestWithRealm((realmFactory, _) =>
+            {
+                RealmLive<RealmBeatmap>? liveBeatmap = null;
+                Task.Factory.StartNew(() =>
+                {
+                    using (var threadContext = realmFactory.CreateContext())
+                    {
+                        var beatmap = threadContext.Write(r => r.Add(new RealmBeatmap(CreateRuleset(), new RealmBeatmapDifficulty(), new RealmBeatmapMetadata())));
+
+                        liveBeatmap = beatmap.ToLive();
+                    }
+                }, TaskCreationOptions.LongRunning | TaskCreationOptions.HideScheduler).Wait();
+
+                Debug.Assert(liveBeatmap != null);
+
+                Task.Factory.StartNew(() =>
+                {
+                    liveBeatmap.PerformWrite(beatmap => { beatmap.Hidden = true; });
+                    liveBeatmap.PerformRead(beatmap => { Assert.IsTrue(beatmap.Hidden); });
+                }, TaskCreationOptions.LongRunning | TaskCreationOptions.HideScheduler).Wait();
+            });
+        }
+
+        [Test]
+        public void TestValueAccessWithoutOpenContextFails()
+        {
+            RunTestWithRealm((realmFactory, _) =>
+            {
+                RealmLive<RealmBeatmap>? liveBeatmap = null;
+                Task.Factory.StartNew(() =>
+                {
+                    using (var threadContext = realmFactory.CreateContext())
+                    {
+                        var beatmap = threadContext.Write(r => r.Add(new RealmBeatmap(CreateRuleset(), new RealmBeatmapDifficulty(), new RealmBeatmapMetadata())));
+
+                        liveBeatmap = beatmap.ToLive();
+                    }
+                }, TaskCreationOptions.LongRunning | TaskCreationOptions.HideScheduler).Wait();
+
+                Debug.Assert(liveBeatmap != null);
+
+                Task.Factory.StartNew(() =>
+                {
+                    Assert.Throws<InvalidOperationException>(() =>
+                    {
+                        var unused = liveBeatmap.Value;
+                    });
+                }, TaskCreationOptions.LongRunning | TaskCreationOptions.HideScheduler).Wait();
+            });
+        }
+
+        [Test]
+        public void TestLiveAssumptions()
+        {
+            RunTestWithRealm((realmFactory, _) =>
+            {
+                int changesTriggered = 0;
+
+                using (var updateThreadContext = realmFactory.CreateContext())
+                {
+                    updateThreadContext.All<RealmBeatmap>().SubscribeForNotifications(gotChange);
+                    RealmLive<RealmBeatmap>? liveBeatmap = null;
+
+                    Task.Factory.StartNew(() =>
+                    {
+                        using (var threadContext = realmFactory.CreateContext())
+                        {
+                            var ruleset = CreateRuleset();
+                            var beatmap = threadContext.Write(r => r.Add(new RealmBeatmap(ruleset, new RealmBeatmapDifficulty(), new RealmBeatmapMetadata())));
+
+                            // add a second beatmap to ensure that a full refresh occurs below.
+                            // not just a refresh from the resolved Live.
+                            threadContext.Write(r => r.Add(new RealmBeatmap(ruleset, new RealmBeatmapDifficulty(), new RealmBeatmapMetadata())));
+
+                            liveBeatmap = beatmap.ToLive();
+                        }
+                    }, TaskCreationOptions.LongRunning | TaskCreationOptions.HideScheduler).Wait();
+
+                    Debug.Assert(liveBeatmap != null);
+
+                    // not yet seen by main context
+                    Assert.AreEqual(0, updateThreadContext.All<RealmBeatmap>().Count());
+                    Assert.AreEqual(0, changesTriggered);
+
+                    var resolved = liveBeatmap.Value;
+
+                    // retrieval causes an implicit refresh. even changes that aren't related to the retrieval are fired at this point.
+                    Assert.AreEqual(2, updateThreadContext.All<RealmBeatmap>().Count());
+                    Assert.AreEqual(1, changesTriggered);
+
+                    // even though the realm that this instance was resolved for was closed, it's still valid.
+                    Assert.IsTrue(resolved.Realm.IsClosed);
+                    Assert.IsTrue(resolved.IsValid);
+
+                    // can access properties without a crash.
+                    Assert.IsFalse(resolved.Hidden);
+
+                    updateThreadContext.Write(r =>
+                    {
+                        // can use with the main context.
+                        r.Remove(resolved);
+                    });
+                }
+
+                void gotChange(IRealmCollection<RealmBeatmap> sender, ChangeSet changes, Exception error)
+                {
+                    changesTriggered++;
+                }
+            });
+        }
+    }
+}

osu.Game.Tests/Database/RealmTest.cs

@@ -4,12 +4,13 @@
 using System;
 using System.Runtime.CompilerServices;
 using System.Threading.Tasks;
-using Nito.AsyncEx;
 using NUnit.Framework;
+using osu.Framework.Extensions;
 using osu.Framework.Logging;
 using osu.Framework.Platform;
 using osu.Framework.Testing;
 using osu.Game.Database;
+using osu.Game.Models;
 
 #nullable enable
 
@@ -28,42 +29,109 @@ namespace osu.Game.Tests.Database
 
         protected void RunTestWithRealm(Action<RealmContextFactory, Storage> testAction, [CallerMemberName] string caller = "")
         {
-            AsyncContext.Run(() =>
+            using (HeadlessGameHost host = new CleanRunHeadlessGameHost(caller))
             {
-                var testStorage = storage.GetStorageForDirectory(caller);
-
-                using (var realmFactory = new RealmContextFactory(testStorage, caller))
+                host.Run(new RealmTestGame(() =>
                 {
-                    Logger.Log($"Running test using realm file {testStorage.GetFullPath(realmFactory.Filename)}");
-                    testAction(realmFactory, testStorage);
+                    var testStorage = storage.GetStorageForDirectory(caller);
 
-                    realmFactory.Dispose();
+                    using (var realmFactory = new RealmContextFactory(testStorage, caller))
+                    {
+                        Logger.Log($"Running test using realm file {testStorage.GetFullPath(realmFactory.Filename)}");
+                        testAction(realmFactory, testStorage);
 
-                    Logger.Log($"Final database size: {getFileSize(testStorage, realmFactory)}");
-                    realmFactory.Compact();
-                    Logger.Log($"Final database size after compact: {getFileSize(testStorage, realmFactory)}");
-                }
-            });
+                        realmFactory.Dispose();
+
+                        Logger.Log($"Final database size: {getFileSize(testStorage, realmFactory)}");
+                        realmFactory.Compact();
+                        Logger.Log($"Final database size after compact: {getFileSize(testStorage, realmFactory)}");
+                    }
+                }));
+            }
         }
 
         protected void RunTestWithRealmAsync(Func<RealmContextFactory, Storage, Task> testAction, [CallerMemberName] string caller = "")
         {
-            AsyncContext.Run(async () =>
+            using (HeadlessGameHost host = new CleanRunHeadlessGameHost(caller))
             {
-                var testStorage = storage.GetStorageForDirectory(caller);
-
-                using (var realmFactory = new RealmContextFactory(testStorage, caller))
+                host.Run(new RealmTestGame(async () =>
                 {
-                    Logger.Log($"Running test using realm file {testStorage.GetFullPath(realmFactory.Filename)}");
-                    await testAction(realmFactory, testStorage);
+                    var testStorage = storage.GetStorageForDirectory(caller);
 
-                    realmFactory.Dispose();
+                    using (var realmFactory = new RealmContextFactory(testStorage, caller))
+                    {
+                        Logger.Log($"Running test using realm file {testStorage.GetFullPath(realmFactory.Filename)}");
+                        await testAction(realmFactory, testStorage);
 
-                    Logger.Log($"Final database size: {getFileSize(testStorage, realmFactory)}");
-                    realmFactory.Compact();
-                    Logger.Log($"Final database size after compact: {getFileSize(testStorage, realmFactory)}");
+                        realmFactory.Dispose();
+
+                        Logger.Log($"Final database size: {getFileSize(testStorage, realmFactory)}");
+                        realmFactory.Compact();
+                    }
+                }));
+            }
+        }
+
+        protected static RealmBeatmapSet CreateBeatmapSet(RealmRuleset ruleset)
+        {
+            RealmFile createRealmFile() => new RealmFile { Hash = Guid.NewGuid().ToString().ComputeSHA2Hash() };
+
+            var metadata = new RealmBeatmapMetadata
+            {
+                Title = "My Love",
+                Artist = "Kuba Oms"
+            };
+
+            var beatmapSet = new RealmBeatmapSet
+            {
+                Beatmaps =
+                {
+                    new RealmBeatmap(ruleset, new RealmBeatmapDifficulty(), metadata) { DifficultyName = "Easy", },
+                    new RealmBeatmap(ruleset, new RealmBeatmapDifficulty(), metadata) { DifficultyName = "Normal", },
+                    new RealmBeatmap(ruleset, new RealmBeatmapDifficulty(), metadata) { DifficultyName = "Hard", },
+                    new RealmBeatmap(ruleset, new RealmBeatmapDifficulty(), metadata) { DifficultyName = "Insane", }
+                },
+                Files =
+                {
+                    new RealmNamedFileUsage(createRealmFile(), "test [easy].osu"),
+                    new RealmNamedFileUsage(createRealmFile(), "test [normal].osu"),
+                    new RealmNamedFileUsage(createRealmFile(), "test [hard].osu"),
+                    new RealmNamedFileUsage(createRealmFile(), "test [insane].osu"),
                 }
-            });
+            };
+
+            for (int i = 0; i < 8; i++)
+                beatmapSet.Files.Add(new RealmNamedFileUsage(createRealmFile(), $"hitsound{i}.mp3"));
+
+            foreach (var b in beatmapSet.Beatmaps)
+                b.BeatmapSet = beatmapSet;
+
+            return beatmapSet;
+        }
+
+        protected static RealmRuleset CreateRuleset() =>
+            new RealmRuleset(0, "osu!", "osu", true);
+
+        private class RealmTestGame : Framework.Game
+        {
+            public RealmTestGame(Func<Task> work)
+            {
+                // ReSharper disable once AsyncVoidLambda
+                Scheduler.Add(async () =>
+                {
+                    await work().ConfigureAwait(true);
+                    Exit();
+                });
+            }
+
+            public RealmTestGame(Action work)
+            {
+                Scheduler.Add(() =>
+                {
+                    work();
+                    Exit();
+                });
+            }
         }
 
         private static long getFileSize(Storage testStorage, RealmContextFactory realmFactory)

osu.Game.Tests/Skins/TestSceneSkinProvidingContainer.cs

@@ -6,7 +6,6 @@ using System.Linq;
 using NUnit.Framework;
 using osu.Framework.Audio.Sample;
 using osu.Framework.Bindables;
-using osu.Framework.Extensions.IEnumerableExtensions;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.OpenGL.Textures;
 using osu.Framework.Graphics.Textures;
@@ -65,10 +64,9 @@ namespace osu.Game.Tests.Skins
 
             public new void TriggerSourceChanged() => base.TriggerSourceChanged();
 
-            protected override void OnSourceChanged()
+            protected override void RefreshSources()
             {
-                ResetSources();
-                sources.ForEach(AddSource);
+                SetSources(sources);
             }
         }
 

osu.Game.Tests/Visual/Audio/TestSceneAudioFilter.cs

@@ -6,6 +6,7 @@ using NUnit.Framework;
 using osu.Framework.Allocation;
 using osu.Framework.Audio;
 using osu.Framework.Audio.Track;
+using osu.Framework.Bindables;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Framework.Graphics.Sprites;
@@ -18,16 +19,19 @@ namespace osu.Game.Tests.Visual.Audio
 {
     public class TestSceneAudioFilter : OsuTestScene
     {
-        private OsuSpriteText lowpassText;
-        private AudioFilter lowpassFilter;
+        private OsuSpriteText lowPassText;
+        private AudioFilter lowPassFilter;
 
-        private OsuSpriteText highpassText;
-        private AudioFilter highpassFilter;
+        private OsuSpriteText highPassText;
+        private AudioFilter highPassFilter;
 
         private Track track;
 
         private WaveformTestBeatmap beatmap;
 
+        private OsuSliderBar<int> lowPassSlider;
+        private OsuSliderBar<int> highPassSlider;
+
         [BackgroundDependencyLoader]
         private void load(AudioManager audio)
         {
@@ -38,53 +42,89 @@ namespace osu.Game.Tests.Visual.Audio
             {
                 Children = new Drawable[]
                 {
-                    lowpassFilter = new AudioFilter(audio.TrackMixer),
-                    highpassFilter = new AudioFilter(audio.TrackMixer, BQFType.HighPass),
-                    lowpassText = new OsuSpriteText
+                    lowPassFilter = new AudioFilter(audio.TrackMixer),
+                    highPassFilter = new AudioFilter(audio.TrackMixer, BQFType.HighPass),
+                    lowPassText = new OsuSpriteText
                     {
                         Padding = new MarginPadding(20),
-                        Text = $"Low Pass: {lowpassFilter.Cutoff.Value}hz",
+                        Text = $"Low Pass: {lowPassFilter.Cutoff}hz",
                         Font = new FontUsage(size: 40)
                     },
-                    new OsuSliderBar<int>
+                    lowPassSlider = new OsuSliderBar<int>
                     {
                         Width = 500,
                         Height = 50,
                         Padding = new MarginPadding(20),
-                        Current = { BindTarget = lowpassFilter.Cutoff }
+                        Current = new BindableInt
+                        {
+                            MinValue = 0,
+                            MaxValue = AudioFilter.MAX_LOWPASS_CUTOFF,
+                        }
                     },
-                    highpassText = new OsuSpriteText
+                    highPassText = new OsuSpriteText
                     {
                         Padding = new MarginPadding(20),
-                        Text = $"High Pass: {highpassFilter.Cutoff.Value}hz",
+                        Text = $"High Pass: {highPassFilter.Cutoff}hz",
                         Font = new FontUsage(size: 40)
                     },
-                    new OsuSliderBar<int>
+                    highPassSlider = new OsuSliderBar<int>
                     {
                         Width = 500,
                         Height = 50,
                         Padding = new MarginPadding(20),
-                        Current = { BindTarget = highpassFilter.Cutoff }
+                        Current = new BindableInt
+                        {
+                            MinValue = 0,
+                            MaxValue = AudioFilter.MAX_LOWPASS_CUTOFF,
+                        }
                     }
                 }
             });
-            lowpassFilter.Cutoff.ValueChanged += e => lowpassText.Text = $"Low Pass: {e.NewValue}hz";
-            highpassFilter.Cutoff.ValueChanged += e => highpassText.Text = $"High Pass: {e.NewValue}hz";
+
+            lowPassSlider.Current.ValueChanged += e =>
+            {
+                lowPassText.Text = $"Low Pass: {e.NewValue}hz";
+                lowPassFilter.Cutoff = e.NewValue;
+            };
+
+            highPassSlider.Current.ValueChanged += e =>
+            {
+                highPassText.Text = $"High Pass: {e.NewValue}hz";
+                highPassFilter.Cutoff = e.NewValue;
+            };
         }
 
+        #region Overrides of Drawable
+
+        protected override void Update()
+        {
+            base.Update();
+            highPassSlider.Current.Value = highPassFilter.Cutoff;
+            lowPassSlider.Current.Value = lowPassFilter.Cutoff;
+        }
+
+        #endregion
+
         [SetUpSteps]
         public void SetUpSteps()
         {
             AddStep("Play Track", () => track.Start());
+
+            AddStep("Reset filters", () =>
+            {
+                lowPassFilter.Cutoff = AudioFilter.MAX_LOWPASS_CUTOFF;
+                highPassFilter.Cutoff = 0;
+            });
+
             waitTrackPlay();
         }
 
         [Test]
-        public void TestLowPass()
+        public void TestLowPassSweep()
         {
             AddStep("Filter Sweep", () =>
             {
-                lowpassFilter.CutoffTo(AudioFilter.MAX_LOWPASS_CUTOFF).Then()
+                lowPassFilter.CutoffTo(AudioFilter.MAX_LOWPASS_CUTOFF).Then()
                              .CutoffTo(0, 2000, Easing.OutCubic);
             });
 
@@ -92,7 +132,7 @@ namespace osu.Game.Tests.Visual.Audio
 
             AddStep("Filter Sweep (reverse)", () =>
             {
-                lowpassFilter.CutoffTo(0).Then()
+                lowPassFilter.CutoffTo(0).Then()
                              .CutoffTo(AudioFilter.MAX_LOWPASS_CUTOFF, 2000, Easing.InCubic);
             });
 
@@ -101,11 +141,11 @@ namespace osu.Game.Tests.Visual.Audio
         }
 
         [Test]
-        public void TestHighPass()
+        public void TestHighPassSweep()
         {
             AddStep("Filter Sweep", () =>
             {
-                highpassFilter.CutoffTo(0).Then()
+                highPassFilter.CutoffTo(0).Then()
                               .CutoffTo(AudioFilter.MAX_LOWPASS_CUTOFF, 2000, Easing.InCubic);
             });
 
@@ -113,7 +153,7 @@ namespace osu.Game.Tests.Visual.Audio
 
             AddStep("Filter Sweep (reverse)", () =>
             {
-                highpassFilter.CutoffTo(AudioFilter.MAX_LOWPASS_CUTOFF).Then()
+                highPassFilter.CutoffTo(AudioFilter.MAX_LOWPASS_CUTOFF).Then()
                               .CutoffTo(0, 2000, Easing.OutCubic);
             });
 

osu.Game.Tests/Visual/Editing/TestSceneEditorSaving.cs

@@ -32,6 +32,8 @@ namespace osu.Game.Tests.Visual.Editing
 
             AddUntilStep("wait for editor load", () => editor != null);
 
+            AddStep("Set overall difficulty", () => editorBeatmap.Difficulty.OverallDifficulty = 7);
+
             AddStep("Add timing point", () => editorBeatmap.ControlPointInfo.Add(0, new TimingControlPoint()));
 
             AddStep("Enter compose mode", () => InputManager.Key(Key.F1));
@@ -41,11 +43,11 @@ namespace osu.Game.Tests.Visual.Editing
             AddStep("Move to playfield", () => InputManager.MoveMouseTo(Game.ScreenSpaceDrawQuad.Centre));
             AddStep("Place single hitcircle", () => InputManager.Click(MouseButton.Left));
 
-            AddStep("Save and exit", () =>
-            {
-                InputManager.Keys(PlatformAction.Save);
-                InputManager.Key(Key.Escape);
-            });
+            AddAssert("Beatmap contains single hitcircle", () => editorBeatmap.HitObjects.Count == 1);
+
+            AddStep("Save", () => InputManager.Keys(PlatformAction.Save));
+
+            AddStep("Exit", () => InputManager.Key(Key.Escape));
 
             AddUntilStep("Wait for main menu", () => Game.ScreenStack.CurrentScreen is MainMenu);
 
@@ -57,6 +59,7 @@ namespace osu.Game.Tests.Visual.Editing
 
             AddUntilStep("Wait for editor load", () => editor != null);
             AddAssert("Beatmap contains single hitcircle", () => editorBeatmap.HitObjects.Count == 1);
+            AddAssert("Beatmap has correct overall difficulty", () => editorBeatmap.Difficulty.OverallDifficulty == 7);
         }
     }
 }

osu.Game.Tests/Visual/Gameplay/TestSceneFrameStabilityContainer.cs

@@ -103,6 +103,30 @@ namespace osu.Game.Tests.Visual.Gameplay
             checkFrameCount(0);
         }
 
+        [Test]
+        public void TestRatePreservedWhenTimeNotProgressing()
+        {
+            AddStep("set manual clock rate", () => manualClock.Rate = 1);
+            seekManualTo(5000);
+            createStabilityContainer();
+            checkRate(1);
+
+            seekManualTo(10000);
+            checkRate(1);
+
+            AddWaitStep("wait some", 3);
+            checkRate(1);
+
+            seekManualTo(5000);
+            checkRate(-1);
+
+            AddWaitStep("wait some", 3);
+            checkRate(-1);
+
+            seekManualTo(10000);
+            checkRate(1);
+        }
+
         private const int max_frames_catchup = 50;
 
         private void createStabilityContainer(double gameplayStartTime = double.MinValue) => AddStep("create container", () =>
@@ -116,6 +140,9 @@ namespace osu.Game.Tests.Visual.Gameplay
         private void checkFrameCount(int frames) =>
             AddAssert($"elapsed frames is {frames}", () => consumer.ElapsedFrames == frames);
 
+        private void checkRate(double rate) =>
+            AddAssert($"clock rate is {rate}", () => consumer.Clock.Rate == rate);
+
         public class ClockConsumingChild : CompositeDrawable
         {
             private readonly OsuSpriteText text;

osu.Game.Tests/Visual/Gameplay/TestSceneStoryboardWithOutro.cs

@@ -90,8 +90,12 @@ namespace osu.Game.Tests.Visual.Gameplay
             CreateTest(() =>
             {
                 AddStep("fail on first judgement", () => currentFailConditions = (_, __) => true);
-                AddStep("set storyboard duration to 1.3s", () => currentStoryboardDuration = 1300);
+
+                // Fail occurs at 164ms with the provided beatmap.
+                // Fail animation runs for 2.5s realtime but the gameplay time change is *variable* due to the frequency transform being applied, so we need a bit of lenience.
+                AddStep("set storyboard duration to 0.6s", () => currentStoryboardDuration = 600);
             });
+
             AddUntilStep("wait for fail", () => Player.HasFailed);
             AddUntilStep("storyboard ends", () => Player.GameplayClockContainer.GameplayClock.CurrentTime >= currentStoryboardDuration);
             AddUntilStep("wait for fail overlay", () => Player.FailOverlay.State.Value == Visibility.Visible);

osu.Game.Tests/Visual/Navigation/TestSceneStartupImport.cs

@@ -0,0 +1,31 @@
+// 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.
+
+using System.Linq;
+using NUnit.Framework;
+using osu.Framework.Testing;
+using osu.Game.Database;
+using osu.Game.Tests.Resources;
+
+namespace osu.Game.Tests.Visual.Navigation
+{
+    public class TestSceneStartupImport : OsuGameTestScene
+    {
+        private string importFilename;
+
+        protected override TestOsuGame CreateTestGame() => new TestOsuGame(LocalStorage, API, new[] { importFilename });
+
+        public override void SetUpSteps()
+        {
+            AddStep("Prepare import beatmap", () => importFilename = TestResources.GetTestBeatmapForImport());
+
+            base.SetUpSteps();
+        }
+
+        [Test]
+        public void TestImportCreatedNotification()
+        {
+            AddUntilStep("Import notification was presented", () => Game.Notifications.ChildrenOfType<ImportProgressNotification>().Count() == 1);
+        }
+    }
+}

osu.Game.Tests/Visual/SongSelect/TestScenePlaySongSelect.cs

@@ -142,6 +142,8 @@ namespace osu.Game.Tests.Visual.SongSelect
 
             AddStep("store selected beatmap", () => selected = Beatmap.Value);
 
+            AddUntilStep("wait for beatmaps to load", () => songSelect.Carousel.ChildrenOfType<DrawableCarouselBeatmap>().Any());
+
             AddStep("select next and enter", () =>
             {
                 InputManager.MoveMouseTo(songSelect.Carousel.ChildrenOfType<DrawableCarouselBeatmap>()
@@ -599,10 +601,10 @@ namespace osu.Game.Tests.Visual.SongSelect
             });
 
             FilterableDifficultyIcon difficultyIcon = null;
-            AddStep("Find an icon", () =>
+            AddUntilStep("Find an icon", () =>
             {
-                difficultyIcon = set.ChildrenOfType<FilterableDifficultyIcon>()
-                                    .First(icon => getDifficultyIconIndex(set, icon) != getCurrentBeatmapIndex());
+                return (difficultyIcon = set.ChildrenOfType<FilterableDifficultyIcon>()
+                                            .FirstOrDefault(icon => getDifficultyIconIndex(set, icon) != getCurrentBeatmapIndex())) != null;
             });
 
             AddStep("Click on a difficulty", () =>
@@ -765,10 +767,10 @@ namespace osu.Game.Tests.Visual.SongSelect
             });
 
             FilterableGroupedDifficultyIcon groupIcon = null;
-            AddStep("Find group icon for different ruleset", () =>
+            AddUntilStep("Find group icon for different ruleset", () =>
             {
-                groupIcon = set.ChildrenOfType<FilterableGroupedDifficultyIcon>()
-                               .First(icon => icon.Items.First().BeatmapInfo.Ruleset.ID == 3);
+                return (groupIcon = set.ChildrenOfType<FilterableGroupedDifficultyIcon>()
+                                       .FirstOrDefault(icon => icon.Items.First().BeatmapInfo.Ruleset.ID == 3)) != null;
             });
 
             AddAssert("Check ruleset is osu!", () => Ruleset.Value.ID == 0);

osu.Game/Audio/Effects/AudioFilter.cs

@@ -4,7 +4,6 @@
 using System.Diagnostics;
 using ManagedBass.Fx;
 using osu.Framework.Audio.Mixing;
-using osu.Framework.Bindables;
 using osu.Framework.Graphics;
 
 namespace osu.Game.Audio.Effects
@@ -21,10 +20,25 @@ namespace osu.Game.Audio.Effects
         private readonly BQFParameters filter;
         private readonly BQFType type;
 
+        private bool isAttached;
+
+        private int cutoff;
+
         /// <summary>
-        /// The current cutoff of this filter.
+        /// The cutoff frequency of this filter.
         /// </summary>
-        public BindableNumber<int> Cutoff { get; }
+        public int Cutoff
+        {
+            get => cutoff;
+            set
+            {
+                if (value == cutoff)
+                    return;
+
+                cutoff = value;
+                updateFilter(cutoff);
+            }
+        }
 
         /// <summary>
         /// A Component that implements a BASS FX BiQuad Filter Effect.
@@ -36,102 +50,96 @@ namespace osu.Game.Audio.Effects
             this.mixer = mixer;
             this.type = type;
 
-            int initialCutoff;
-
-            switch (type)
-            {
-                case BQFType.HighPass:
-                    initialCutoff = 1;
-                    break;
-
-                case BQFType.LowPass:
-                    initialCutoff = MAX_LOWPASS_CUTOFF;
-                    break;
-
-                default:
-                    initialCutoff = 500; // A default that should ensure audio remains audible for other filters.
-                    break;
-            }
-
-            Cutoff = new BindableNumber<int>(initialCutoff)
-            {
-                MinValue = 1,
-                MaxValue = MAX_LOWPASS_CUTOFF
-            };
-
             filter = new BQFParameters
             {
                 lFilter = type,
-                fCenter = initialCutoff,
                 fBandwidth = 0,
-                fQ = 0.7f // This allows fCenter to go up to 22049hz (nyquist - 1hz) without overflowing and causing weird filter behaviour (see: https://www.un4seen.com/forum/?topic=19542.0)
+                // This allows fCenter to go up to 22049hz (nyquist - 1hz) without overflowing and causing weird filter behaviour (see: https://www.un4seen.com/forum/?topic=19542.0)
+                fQ = 0.7f
             };
 
-            // Don't start attached if this is low-pass or high-pass filter (as they have special auto-attach/detach logic)
-            if (type != BQFType.LowPass && type != BQFType.HighPass)
-                attachFilter();
-
-            Cutoff.ValueChanged += updateFilter;
+            Cutoff = getInitialCutoff(type);
         }
 
-        private void attachFilter()
+        private int getInitialCutoff(BQFType type)
         {
-            Debug.Assert(!mixer.Effects.Contains(filter));
-            mixer.Effects.Add(filter);
-        }
-
-        private void detachFilter()
-        {
-            Debug.Assert(mixer.Effects.Contains(filter));
-            mixer.Effects.Remove(filter);
-        }
-
-        private void updateFilter(ValueChangedEvent<int> cutoff)
-        {
-            // Workaround for weird behaviour when rapidly setting fCenter of a low-pass filter to nyquist - 1hz.
-            if (type == BQFType.LowPass)
+            switch (type)
             {
-                if (cutoff.NewValue >= MAX_LOWPASS_CUTOFF)
-                {
-                    detachFilter();
-                    return;
-                }
+                case BQFType.HighPass:
+                    return 1;
 
-                if (cutoff.OldValue >= MAX_LOWPASS_CUTOFF && cutoff.NewValue < MAX_LOWPASS_CUTOFF)
-                    attachFilter();
+                case BQFType.LowPass:
+                    return MAX_LOWPASS_CUTOFF;
+
+                default:
+                    return 500; // A default that should ensure audio remains audible for other filters.
+            }
+        }
+
+        private void updateFilter(int newValue)
+        {
+            switch (type)
+            {
+                case BQFType.LowPass:
+                    // Workaround for weird behaviour when rapidly setting fCenter of a low-pass filter to nyquist - 1hz.
+                    if (newValue >= MAX_LOWPASS_CUTOFF)
+                    {
+                        ensureDetached();
+                        return;
+                    }
+
+                    break;
+
+                // Workaround for weird behaviour when rapidly setting fCenter of a high-pass filter to 1hz.
+                case BQFType.HighPass:
+                    if (newValue <= 1)
+                    {
+                        ensureDetached();
+                        return;
+                    }
+
+                    break;
             }
 
-            // Workaround for weird behaviour when rapidly setting fCenter of a high-pass filter to 1hz.
-            if (type == BQFType.HighPass)
-            {
-                if (cutoff.NewValue <= 1)
-                {
-                    detachFilter();
-                    return;
-                }
-
-                if (cutoff.OldValue <= 1 && cutoff.NewValue > 1)
-                    attachFilter();
-            }
+            ensureAttached();
 
             var filterIndex = mixer.Effects.IndexOf(filter);
+
             if (filterIndex < 0) return;
 
             if (mixer.Effects[filterIndex] is BQFParameters existingFilter)
             {
-                existingFilter.fCenter = cutoff.NewValue;
+                existingFilter.fCenter = newValue;
 
                 // required to update effect with new parameters.
                 mixer.Effects[filterIndex] = existingFilter;
             }
         }
 
+        private void ensureAttached()
+        {
+            if (isAttached)
+                return;
+
+            Debug.Assert(!mixer.Effects.Contains(filter));
+            mixer.Effects.Add(filter);
+            isAttached = true;
+        }
+
+        private void ensureDetached()
+        {
+            if (!isAttached)
+                return;
+
+            Debug.Assert(mixer.Effects.Contains(filter));
+            mixer.Effects.Remove(filter);
+            isAttached = false;
+        }
+
         protected override void Dispose(bool isDisposing)
         {
             base.Dispose(isDisposing);
-
-            if (mixer.Effects.Contains(filter))
-                detachFilter();
+            ensureDetached();
         }
     }
 }

osu.Game/Audio/Effects/ITransformableFilter.cs

@@ -1,7 +1,6 @@
 // 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.
 
-using osu.Framework.Bindables;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Transforms;
 
@@ -12,7 +11,7 @@ namespace osu.Game.Audio.Effects
         /// <summary>
         /// The filter cutoff.
         /// </summary>
-        BindableNumber<int> Cutoff { get; }
+        int Cutoff { get; set; }
     }
 
     public static class FilterableAudioComponentExtensions
@@ -40,7 +39,7 @@ namespace osu.Game.Audio.Effects
         public static TransformSequence<T> CutoffTo<T, TEasing>(this T component, int newCutoff, double duration, TEasing easing)
             where T : class, ITransformableFilter, IDrawable
             where TEasing : IEasingFunction
-            => component.TransformBindableTo(component.Cutoff, newCutoff, duration, easing);
+            => component.TransformTo(nameof(component.Cutoff), newCutoff, duration, easing);
 
         /// <summary>
         /// Smoothly adjusts filter cutoff over time.
@@ -49,6 +48,6 @@ namespace osu.Game.Audio.Effects
         public static TransformSequence<T> CutoffTo<T, TEasing>(this TransformSequence<T> sequence, int newCutoff, double duration, TEasing easing)
             where T : class, ITransformableFilter, IDrawable
             where TEasing : IEasingFunction
-            => sequence.Append(o => o.TransformBindableTo(o.Cutoff, newCutoff, duration, easing));
+            => sequence.Append(o => o.TransformTo(nameof(o.Cutoff), newCutoff, duration, easing));
     }
 }

osu.Game/Beatmaps/BeatmapConverter.cs

@@ -40,7 +40,13 @@ namespace osu.Game.Beatmaps
         public IBeatmap Convert(CancellationToken cancellationToken = default)
         {
             // We always operate on a clone of the original beatmap, to not modify it game-wide
-            return ConvertBeatmap(Beatmap.Clone(), cancellationToken);
+            var original = Beatmap.Clone();
+
+            // Shallow clone isn't enough to ensure we don't mutate beatmap info unexpectedly.
+            // Can potentially be removed after `Beatmap.Difficulty` doesn't save back to `Beatmap.BeatmapInfo`.
+            original.BeatmapInfo = original.BeatmapInfo.Clone();
+
+            return ConvertBeatmap(original, cancellationToken);
         }
 
         /// <summary>

osu.Game/Configuration/RandomSelectAlgorithm.cs

@@ -10,7 +10,7 @@ namespace osu.Game.Configuration
         [Description("Never repeat")]
         RandomPermutation,
 
-        [Description("Random")]
+        [Description("True Random")]
         Random
     }
 }

osu.Game/Database/ArchiveModelManager.cs

@@ -116,7 +116,7 @@ namespace osu.Game.Database
         /// <param name="paths">One or more archive locations on disk.</param>
         public Task Import(params string[] paths)
         {
-            var notification = new ProgressNotification { State = ProgressNotificationState.Active };
+            var notification = new ImportProgressNotification();
 
             PostNotification?.Invoke(notification);
 
@@ -125,7 +125,7 @@ namespace osu.Game.Database
 
         public Task Import(params ImportTask[] tasks)
         {
-            var notification = new ProgressNotification { State = ProgressNotificationState.Active };
+            var notification = new ImportProgressNotification();
 
             PostNotification?.Invoke(notification);
 

osu.Game/Database/IHasRealmFiles.cs

@@ -0,0 +1,20 @@
+// 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.
+
+using System.Collections.Generic;
+using osu.Game.Models;
+
+#nullable enable
+
+namespace osu.Game.Database
+{
+    /// <summary>
+    /// A model that contains a list of files it is responsible for.
+    /// </summary>
+    public interface IHasRealmFiles
+    {
+        IList<RealmNamedFileUsage> Files { get; }
+
+        string Hash { get; set; }
+    }
+}

osu.Game/Database/INamedFile.cs

@@ -0,0 +1,19 @@
+// 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.
+
+using osu.Game.Models;
+
+#nullable enable
+
+namespace osu.Game.Database
+{
+    /// <summary>
+    /// Represents a join model which gives a filename and scope to a <see cref="File"/>.
+    /// </summary>
+    public interface INamedFile
+    {
+        string Filename { get; set; }
+
+        RealmFile File { get; set; }
+    }
+}

osu.Game/Database/ImportProgressNotification.cs

@@ -0,0 +1,15 @@
+// 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.
+
+using osu.Game.Overlays.Notifications;
+
+namespace osu.Game.Database
+{
+    public class ImportProgressNotification : ProgressNotification
+    {
+        public ImportProgressNotification()
+        {
+            State = ProgressNotificationState.Active;
+        }
+    }
+}

osu.Game/Database/RealmContextFactory.cs

@@ -135,9 +135,8 @@ namespace osu.Game.Database
             if (IsDisposed)
                 throw new ObjectDisposedException(nameof(RealmContextFactory));
 
-            // TODO: this can be added for safety once we figure how to bypass in test
-            // if (!ThreadSafety.IsUpdateThread)
-            //     throw new InvalidOperationException($"{nameof(BlockAllOperations)} must be called from the update thread.");
+            if (!ThreadSafety.IsUpdateThread)
+                throw new InvalidOperationException($"{nameof(BlockAllOperations)} must be called from the update thread.");
 
             Logger.Log(@"Blocking realm operations.", LoggingTarget.Database);
 

osu.Game/Database/RealmLive.cs

@@ -0,0 +1,111 @@
+// 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.
+
+using System;
+using System.Threading;
+using Realms;
+
+#nullable enable
+
+namespace osu.Game.Database
+{
+    /// <summary>
+    /// Provides a method of working with realm objects over longer application lifetimes.
+    /// </summary>
+    /// <typeparam name="T">The underlying object type.</typeparam>
+    public class RealmLive<T> : ILive<T> where T : RealmObject, IHasGuidPrimaryKey
+    {
+        public Guid ID { get; }
+
+        private readonly SynchronizationContext? fetchedContext;
+        private readonly int fetchedThreadId;
+
+        /// <summary>
+        /// The original live data used to create this instance.
+        /// </summary>
+        private readonly T data;
+
+        /// <summary>
+        /// Construct a new instance of live realm data.
+        /// </summary>
+        /// <param name="data">The realm data.</param>
+        public RealmLive(T data)
+        {
+            this.data = data;
+
+            fetchedContext = SynchronizationContext.Current;
+            fetchedThreadId = Thread.CurrentThread.ManagedThreadId;
+
+            ID = data.ID;
+        }
+
+        /// <summary>
+        /// Perform a read operation on this live object.
+        /// </summary>
+        /// <param name="perform">The action to perform.</param>
+        public void PerformRead(Action<T> perform)
+        {
+            if (originalDataValid)
+            {
+                perform(data);
+                return;
+            }
+
+            using (var realm = Realm.GetInstance(data.Realm.Config))
+                perform(realm.Find<T>(ID));
+        }
+
+        /// <summary>
+        /// Perform a read operation on this live object.
+        /// </summary>
+        /// <param name="perform">The action to perform.</param>
+        public TReturn PerformRead<TReturn>(Func<T, TReturn> perform)
+        {
+            if (typeof(RealmObjectBase).IsAssignableFrom(typeof(TReturn)))
+                throw new InvalidOperationException($"Realm live objects should not exit the scope of {nameof(PerformRead)}.");
+
+            if (originalDataValid)
+                return perform(data);
+
+            using (var realm = Realm.GetInstance(data.Realm.Config))
+                return perform(realm.Find<T>(ID));
+        }
+
+        /// <summary>
+        /// Perform a write operation on this live object.
+        /// </summary>
+        /// <param name="perform">The action to perform.</param>
+        public void PerformWrite(Action<T> perform) =>
+            PerformRead(t =>
+            {
+                var transaction = t.Realm.BeginWrite();
+                perform(t);
+                transaction.Commit();
+            });
+
+        public T Value
+        {
+            get
+            {
+                if (originalDataValid)
+                    return data;
+
+                T retrieved;
+
+                using (var realm = Realm.GetInstance(data.Realm.Config))
+                    retrieved = realm.Find<T>(ID);
+
+                if (!retrieved.IsValid)
+                    throw new InvalidOperationException("Attempted to access value without an open context");
+
+                return retrieved;
+            }
+        }
+
+        private bool originalDataValid => isCorrectThread && data.IsValid;
+
+        // this matches realm's internal thread validation (see https://github.com/realm/realm-dotnet/blob/903b4d0b304f887e37e2d905384fb572a6496e70/Realm/Realm/Native/SynchronizationContextScheduler.cs#L72)
+        private bool isCorrectThread
+            => (fetchedContext != null && SynchronizationContext.Current == fetchedContext) || fetchedThreadId == Thread.CurrentThread.ManagedThreadId;
+    }
+}

osu.Game/Database/RealmObjectExtensions.cs

@@ -2,6 +2,7 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using System.Collections.Generic;
+using System.Linq;
 using AutoMapper;
 using osu.Game.Input.Bindings;
 using Realms;
@@ -47,5 +48,17 @@ namespace osu.Game.Database
 
             return mapper.Map<T>(item);
         }
+
+        public static List<RealmLive<T>> ToLive<T>(this IEnumerable<T> realmList)
+            where T : RealmObject, IHasGuidPrimaryKey
+        {
+            return realmList.Select(l => new RealmLive<T>(l)).ToList();
+        }
+
+        public static RealmLive<T> ToLive<T>(this T realmObject)
+            where T : RealmObject, IHasGuidPrimaryKey
+        {
+            return new RealmLive<T>(realmObject);
+        }
     }
 }

osu.Game/Localisation/AudioSettingsStrings.cs

@@ -24,6 +24,11 @@ namespace osu.Game.Localisation
         /// </summary>
         public static LocalisableString VolumeHeader => new TranslatableString(getKey(@"volume_header"), @"Volume");
 
+        /// <summary>
+        /// "Output device"
+        /// </summary>
+        public static LocalisableString OutputDevice => new TranslatableString(getKey(@"output_device"), @"Output device");
+
         /// <summary>
         /// "Master"
         /// </summary>

osu.Game/Localisation/GameplaySettingsStrings.cs

@@ -14,11 +14,36 @@ namespace osu.Game.Localisation
         /// </summary>
         public static LocalisableString GameplaySectionHeader => new TranslatableString(getKey(@"gameplay_section_header"), @"Gameplay");
 
+        /// <summary>
+        /// "Beatmap"
+        /// </summary>
+        public static LocalisableString BeatmapHeader => new TranslatableString(getKey(@"beatmap_header"), @"Beatmap");
+
         /// <summary>
         /// "General"
         /// </summary>
         public static LocalisableString GeneralHeader => new TranslatableString(getKey(@"general_header"), @"General");
 
+        /// <summary>
+        /// "Audio"
+        /// </summary>
+        public static LocalisableString AudioHeader => new TranslatableString(getKey(@"audio"), @"Audio");
+
+        /// <summary>
+        /// "HUD"
+        /// </summary>
+        public static LocalisableString HUDHeader => new TranslatableString(getKey(@"h_u_d"), @"HUD");
+
+        /// <summary>
+        /// "Input"
+        /// </summary>
+        public static LocalisableString InputHeader => new TranslatableString(getKey(@"input"), @"Input");
+
+        /// <summary>
+        /// "Background"
+        /// </summary>
+        public static LocalisableString BackgroundHeader => new TranslatableString(getKey(@"background"), @"Background");
+
         /// <summary>
         /// "Background dim"
         /// </summary>

osu.Game/Localisation/GraphicsSettingsStrings.cs

@@ -104,6 +104,11 @@ namespace osu.Game.Localisation
         /// </summary>
         public static LocalisableString HitLighting => new TranslatableString(getKey(@"hit_lighting"), @"Hit lighting");
 
+        /// <summary>
+        /// "Screenshots"
+        /// </summary>
+        public static LocalisableString Screenshots => new TranslatableString(getKey(@"screenshots"), @"Screenshots");
+
         /// <summary>
         /// "Screenshot format"
         /// </summary>

osu.Game/Localisation/RulesetSettingsStrings.cs

@@ -0,0 +1,19 @@
+// 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.
+
+using osu.Framework.Localisation;
+
+namespace osu.Game.Localisation
+{
+    public static class RulesetSettingsStrings
+    {
+        private const string prefix = @"osu.Game.Resources.Localisation.RulesetSettings";
+
+        /// <summary>
+        /// "Rulesets"
+        /// </summary>
+        public static LocalisableString Rulesets => new TranslatableString(getKey(@"rulesets"), @"Rulesets");
+
+        private static string getKey(string key) => $@"{prefix}:{key}";
+    }
+}

osu.Game/Localisation/SkinSettingsStrings.cs

@@ -14,6 +14,11 @@ namespace osu.Game.Localisation
         /// </summary>
         public static LocalisableString SkinSectionHeader => new TranslatableString(getKey(@"skin_section_header"), @"Skin");
 
+        /// <summary>
+        /// "Current skin"
+        /// </summary>
+        public static LocalisableString CurrentSkin => new TranslatableString(getKey(@"current_skin"), @"Current skin");
+
         /// <summary>
         /// "Skin layout editor"
         /// </summary>

osu.Game/Models/RealmBeatmap.cs

@@ -0,0 +1,117 @@
+// 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.
+
+using System;
+using JetBrains.Annotations;
+using Newtonsoft.Json;
+using osu.Framework.Testing;
+using osu.Game.Beatmaps;
+using osu.Game.Database;
+using osu.Game.Rulesets;
+using Realms;
+
+#nullable enable
+
+namespace osu.Game.Models
+{
+    /// <summary>
+    /// A single beatmap difficulty.
+    /// </summary>
+    [ExcludeFromDynamicCompile]
+    [Serializable]
+    [MapTo("Beatmap")]
+    public class RealmBeatmap : RealmObject, IHasGuidPrimaryKey, IBeatmapInfo
+    {
+        [PrimaryKey]
+        public Guid ID { get; set; } = Guid.NewGuid();
+
+        public string DifficultyName { get; set; } = string.Empty;
+
+        public RealmRuleset Ruleset { get; set; } = null!;
+
+        public RealmBeatmapDifficulty Difficulty { get; set; } = null!;
+
+        public RealmBeatmapMetadata Metadata { get; set; } = null!;
+
+        public RealmBeatmapSet? BeatmapSet { get; set; }
+
+        public BeatmapSetOnlineStatus Status
+        {
+            get => (BeatmapSetOnlineStatus)StatusInt;
+            set => StatusInt = (int)value;
+        }
+
+        [MapTo(nameof(Status))]
+        public int StatusInt { get; set; }
+
+        public int? OnlineID { get; set; }
+
+        public double Length { get; set; }
+
+        public double BPM { get; set; }
+
+        public string Hash { get; set; } = string.Empty;
+
+        public double StarRating { get; set; }
+
+        public string MD5Hash { get; set; } = string.Empty;
+
+        [JsonIgnore]
+        public bool Hidden { get; set; }
+
+        public RealmBeatmap(RealmRuleset ruleset, RealmBeatmapDifficulty difficulty, RealmBeatmapMetadata metadata)
+        {
+            Ruleset = ruleset;
+            Difficulty = difficulty;
+            Metadata = metadata;
+        }
+
+        [UsedImplicitly]
+        private RealmBeatmap()
+        {
+        }
+
+        #region Properties we may not want persisted (but also maybe no harm?)
+
+        public double AudioLeadIn { get; set; }
+
+        public float StackLeniency { get; set; } = 0.7f;
+
+        public bool SpecialStyle { get; set; }
+
+        public bool LetterboxInBreaks { get; set; }
+
+        public bool WidescreenStoryboard { get; set; }
+
+        public bool EpilepsyWarning { get; set; }
+
+        public bool SamplesMatchPlaybackRate { get; set; }
+
+        public double DistanceSpacing { get; set; }
+
+        public int BeatDivisor { get; set; }
+
+        public int GridSize { get; set; }
+
+        public double TimelineZoom { get; set; }
+
+        #endregion
+
+        public bool AudioEquals(RealmBeatmap? other) => other != null
+                                                        && BeatmapSet != null
+                                                        && other.BeatmapSet != null
+                                                        && BeatmapSet.Hash == other.BeatmapSet.Hash
+                                                        && Metadata.AudioFile == other.Metadata.AudioFile;
+
+        public bool BackgroundEquals(RealmBeatmap? other) => other != null
+                                                             && BeatmapSet != null
+                                                             && other.BeatmapSet != null
+                                                             && BeatmapSet.Hash == other.BeatmapSet.Hash
+                                                             && Metadata.BackgroundFile == other.Metadata.BackgroundFile;
+
+        IBeatmapMetadataInfo IBeatmapInfo.Metadata => Metadata;
+        IBeatmapSetInfo? IBeatmapInfo.BeatmapSet => BeatmapSet;
+        IRulesetInfo IBeatmapInfo.Ruleset => Ruleset;
+        IBeatmapDifficultyInfo IBeatmapInfo.Difficulty => Difficulty;
+    }
+}

osu.Game/Models/RealmBeatmapDifficulty.cs

@@ -0,0 +1,45 @@
+// 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.
+
+using osu.Framework.Testing;
+using osu.Game.Beatmaps;
+using Realms;
+
+#nullable enable
+
+namespace osu.Game.Models
+{
+    [ExcludeFromDynamicCompile]
+    [MapTo("BeatmapDifficulty")]
+    public class RealmBeatmapDifficulty : EmbeddedObject, IBeatmapDifficultyInfo
+    {
+        public float DrainRate { get; set; } = IBeatmapDifficultyInfo.DEFAULT_DIFFICULTY;
+        public float CircleSize { get; set; } = IBeatmapDifficultyInfo.DEFAULT_DIFFICULTY;
+        public float OverallDifficulty { get; set; } = IBeatmapDifficultyInfo.DEFAULT_DIFFICULTY;
+        public float ApproachRate { get; set; } = IBeatmapDifficultyInfo.DEFAULT_DIFFICULTY;
+
+        public double SliderMultiplier { get; set; } = 1;
+        public double SliderTickRate { get; set; } = 1;
+
+        /// <summary>
+        /// Returns a shallow-clone of this <see cref="RealmBeatmapDifficulty"/>.
+        /// </summary>
+        public RealmBeatmapDifficulty Clone()
+        {
+            var diff = new RealmBeatmapDifficulty();
+            CopyTo(diff);
+            return diff;
+        }
+
+        public void CopyTo(RealmBeatmapDifficulty difficulty)
+        {
+            difficulty.ApproachRate = ApproachRate;
+            difficulty.DrainRate = DrainRate;
+            difficulty.CircleSize = CircleSize;
+            difficulty.OverallDifficulty = OverallDifficulty;
+
+            difficulty.SliderMultiplier = SliderMultiplier;
+            difficulty.SliderTickRate = SliderTickRate;
+        }
+    }
+}

osu.Game/Models/RealmBeatmapMetadata.cs

@@ -0,0 +1,45 @@
+// 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.
+
+using System;
+using Newtonsoft.Json;
+using osu.Framework.Testing;
+using osu.Game.Beatmaps;
+using Realms;
+
+#nullable enable
+
+namespace osu.Game.Models
+{
+    [ExcludeFromDynamicCompile]
+    [Serializable]
+    [MapTo("BeatmapMetadata")]
+    public class RealmBeatmapMetadata : RealmObject, IBeatmapMetadataInfo
+    {
+        public string Title { get; set; } = string.Empty;
+
+        [JsonProperty("title_unicode")]
+        public string TitleUnicode { get; set; } = string.Empty;
+
+        public string Artist { get; set; } = string.Empty;
+
+        [JsonProperty("artist_unicode")]
+        public string ArtistUnicode { get; set; } = string.Empty;
+
+        public string Author { get; set; } = string.Empty; // eventually should be linked to a persisted User.
+
+        public string Source { get; set; } = string.Empty;
+
+        [JsonProperty(@"tags")]
+        public string Tags { get; set; } = string.Empty;
+
+        /// <summary>
+        /// The time in milliseconds to begin playing the track for preview purposes.
+        /// If -1, the track should begin playing at 40% of its length.
+        /// </summary>
+        public int PreviewTime { get; set; }
+
+        public string AudioFile { get; set; } = string.Empty;
+        public string BackgroundFile { get; set; } = string.Empty;
+    }
+}

osu.Game/Models/RealmBeatmapSet.cs

@@ -0,0 +1,78 @@
+// 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.
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using osu.Framework.Testing;
+using osu.Game.Beatmaps;
+using osu.Game.Database;
+using Realms;
+
+#nullable enable
+
+namespace osu.Game.Models
+{
+    [ExcludeFromDynamicCompile]
+    [MapTo("BeatmapSet")]
+    public class RealmBeatmapSet : RealmObject, IHasGuidPrimaryKey, IHasRealmFiles, ISoftDelete, IEquatable<RealmBeatmapSet>, IBeatmapSetInfo
+    {
+        [PrimaryKey]
+        public Guid ID { get; set; } = Guid.NewGuid();
+
+        public int? OnlineID { get; set; }
+
+        public DateTimeOffset DateAdded { get; set; }
+
+        public IBeatmapMetadataInfo? Metadata => Beatmaps.FirstOrDefault()?.Metadata;
+
+        public IList<RealmBeatmap> Beatmaps { get; } = null!;
+
+        public IList<RealmNamedFileUsage> Files { get; } = null!;
+
+        public bool DeletePending { get; set; }
+
+        public string Hash { get; set; } = string.Empty;
+
+        /// <summary>
+        /// Whether deleting this beatmap set should be prohibited (due to it being a system requirement to be present).
+        /// </summary>
+        public bool Protected { get; set; }
+
+        public double MaxStarDifficulty => Beatmaps.Max(b => b.StarRating);
+
+        public double MaxLength => Beatmaps.Max(b => b.Length);
+
+        public double MaxBPM => Beatmaps.Max(b => b.BPM);
+
+        /// <summary>
+        /// Returns the storage path for the file in this beatmapset with the given filename, if any exists, otherwise null.
+        /// The path returned is relative to the user file storage.
+        /// </summary>
+        /// <param name="filename">The name of the file to get the storage path of.</param>
+        public string? GetPathForFile(string filename) => Files.SingleOrDefault(f => string.Equals(f.Filename, filename, StringComparison.OrdinalIgnoreCase))?.File.StoragePath;
+
+        public override string ToString() => Metadata?.ToString() ?? base.ToString();
+
+        public bool Equals(RealmBeatmapSet? other)
+        {
+            if (other == null)
+                return false;
+
+            if (IsManaged && other.IsManaged)
+                return ID == other.ID;
+
+            if (OnlineID.HasValue && other.OnlineID.HasValue)
+                return OnlineID == other.OnlineID;
+
+            if (!string.IsNullOrEmpty(Hash) && !string.IsNullOrEmpty(other.Hash))
+                return Hash == other.Hash;
+
+            return ReferenceEquals(this, other);
+        }
+
+        IEnumerable<IBeatmapInfo> IBeatmapSetInfo.Beatmaps => Beatmaps;
+
+        IEnumerable<INamedFileUsage> IBeatmapSetInfo.Files => Files;
+    }
+}

osu.Game/Models/RealmFile.cs

@@ -0,0 +1,22 @@
+// 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.
+
+using System.IO;
+using osu.Framework.Testing;
+using osu.Game.IO;
+using Realms;
+
+#nullable enable
+
+namespace osu.Game.Models
+{
+    [ExcludeFromDynamicCompile]
+    [MapTo("File")]
+    public class RealmFile : RealmObject, IFileInfo
+    {
+        [PrimaryKey]
+        public string Hash { get; set; } = string.Empty;
+
+        public string StoragePath => Path.Combine(Hash.Remove(1), Hash.Remove(2), Hash);
+    }
+}

osu.Game/Models/RealmNamedFileUsage.cs

@@ -0,0 +1,34 @@
+// 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.
+
+using JetBrains.Annotations;
+using osu.Framework.Testing;
+using osu.Game.Database;
+using osu.Game.IO;
+using Realms;
+
+#nullable enable
+
+namespace osu.Game.Models
+{
+    [ExcludeFromDynamicCompile]
+    public class RealmNamedFileUsage : EmbeddedObject, INamedFile, INamedFileUsage
+    {
+        public RealmFile File { get; set; } = null!;
+
+        public string Filename { get; set; } = null!;
+
+        public RealmNamedFileUsage(RealmFile file, string filename)
+        {
+            File = file;
+            Filename = filename;
+        }
+
+        [UsedImplicitly]
+        private RealmNamedFileUsage()
+        {
+        }
+
+        IFileInfo INamedFileUsage.File => File;
+    }
+}

osu.Game/Models/RealmRuleset.cs

@@ -0,0 +1,63 @@
+// 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.
+
+using System;
+using JetBrains.Annotations;
+using osu.Framework.Testing;
+using osu.Game.Rulesets;
+using Realms;
+
+#nullable enable
+
+namespace osu.Game.Models
+{
+    [ExcludeFromDynamicCompile]
+    [MapTo("Ruleset")]
+    public class RealmRuleset : RealmObject, IEquatable<RealmRuleset>, IRulesetInfo
+    {
+        [PrimaryKey]
+        public string ShortName { get; set; } = string.Empty;
+
+        public int? OnlineID { get; set; }
+
+        public string Name { get; set; } = string.Empty;
+
+        public string InstantiationInfo { get; set; } = string.Empty;
+
+        public RealmRuleset(string shortName, string name, string instantiationInfo, int? onlineID = null)
+        {
+            ShortName = shortName;
+            Name = name;
+            InstantiationInfo = instantiationInfo;
+            OnlineID = onlineID;
+        }
+
+        [UsedImplicitly]
+        private RealmRuleset()
+        {
+        }
+
+        public RealmRuleset(int? onlineID, string name, string shortName, bool available)
+        {
+            OnlineID = onlineID;
+            Name = name;
+            ShortName = shortName;
+            Available = available;
+        }
+
+        public bool Available { get; set; }
+
+        public bool Equals(RealmRuleset? other) => other != null && OnlineID == other.OnlineID && Available == other.Available && Name == other.Name && InstantiationInfo == other.InstantiationInfo;
+
+        public override string ToString() => Name;
+
+        public RealmRuleset Clone() => new RealmRuleset
+        {
+            OnlineID = OnlineID,
+            Name = Name,
+            ShortName = ShortName,
+            InstantiationInfo = InstantiationInfo,
+            Available = Available
+        };
+    }
+}

osu.Game/OsuGame.cs

@@ -211,13 +211,6 @@ namespace osu.Game
         [BackgroundDependencyLoader]
         private void load()
         {
-            if (args?.Length > 0)
-            {
-                var paths = args.Where(a => !a.StartsWith('-')).ToArray();
-                if (paths.Length > 0)
-                    Task.Run(() => Import(paths));
-            }
-
             dependencies.CacheAs(this);
 
             dependencies.Cache(SentryLogger);
@@ -867,6 +860,19 @@ namespace osu.Game
             {
                 if (mode.NewValue != OverlayActivation.All) CloseAllOverlays();
             };
+
+            // Importantly, this should be run after binding PostNotification to the import handlers so they can present the import after game startup.
+            handleStartupImport();
+        }
+
+        private void handleStartupImport()
+        {
+            if (args?.Length > 0)
+            {
+                var paths = args.Where(a => !a.StartsWith('-')).ToArray();
+                if (paths.Length > 0)
+                    Task.Run(() => Import(paths));
+            }
         }
 
         private void showOverlayAboveOthers(OverlayContainer overlay, OverlayContainer[] otherOverlays)

osu.Game/OsuGameBase.cs

@@ -6,6 +6,7 @@ using System.Collections.Generic;
 using System.IO;
 using System.Linq;
 using System.Reflection;
+using System.Threading;
 using osu.Framework.Allocation;
 using osu.Framework.Audio;
 using osu.Framework.Bindables;
@@ -410,11 +411,28 @@ namespace osu.Game
         {
             Logger.Log($@"Migrating osu! data from ""{Storage.GetFullPath(string.Empty)}"" to ""{path}""...");
 
-            using (realmFactory.BlockAllOperations())
+            IDisposable realmBlocker = null;
+
+            try
             {
-                contextFactory.FlushConnections();
+                ManualResetEventSlim readyToRun = new ManualResetEventSlim();
+
+                Scheduler.Add(() =>
+                {
+                    realmBlocker = realmFactory.BlockAllOperations();
+                    contextFactory.FlushConnections();
+
+                    readyToRun.Set();
+                }, false);
+
+                readyToRun.Wait();
+
                 (Storage as OsuStorage)?.Migrate(Host.GetStorage(path));
             }
+            finally
+            {
+                realmBlocker?.Dispose();
+            }
 
             Logger.Log(@"Migration complete!");
         }

osu.Game/Overlays/OSD/TrackedSettingToast.cs

@@ -29,7 +29,7 @@ namespace osu.Game.Overlays.OSD
         private Sample sampleChange;
 
         public TrackedSettingToast(SettingDescription description)
-            : base(description.Name, description.Value, description.Shortcut)
+            : base(description.Name.ToString(), description.Value.ToString(), description.Shortcut.ToString())
         {
             FillFlowContainer<OptionLight> optionLights;
 

osu.Game/Overlays/Settings/Sections/Audio/AudioDevicesSettings.cs

@@ -28,6 +28,7 @@ namespace osu.Game.Overlays.Settings.Sections.Audio
             {
                 dropdown = new AudioDeviceSettingsDropdown
                 {
+                    LabelText = AudioSettingsStrings.OutputDevice,
                     Keywords = new[] { "speaker", "headphone", "output" }
                 }
             };

osu.Game/Overlays/Settings/Sections/Gameplay/AudioSettings.cs

@@ -0,0 +1,34 @@
+// 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.
+
+using osu.Framework.Allocation;
+using osu.Framework.Graphics;
+using osu.Framework.Localisation;
+using osu.Game.Configuration;
+using osu.Game.Localisation;
+
+namespace osu.Game.Overlays.Settings.Sections.Gameplay
+{
+    public class AudioSettings : SettingsSubsection
+    {
+        protected override LocalisableString Header => GameplaySettingsStrings.AudioHeader;
+
+        [BackgroundDependencyLoader]
+        private void load(OsuConfigManager config)
+        {
+            Children = new Drawable[]
+            {
+                new SettingsCheckbox
+                {
+                    LabelText = GameplaySettingsStrings.PositionalHitsounds,
+                    Current = config.GetBindable<bool>(OsuSetting.PositionalHitSounds)
+                },
+                new SettingsCheckbox
+                {
+                    LabelText = GameplaySettingsStrings.AlwaysPlayFirstComboBreak,
+                    Current = config.GetBindable<bool>(OsuSetting.AlwaysPlayFirstComboBreak)
+                },
+            };
+        }
+    }
+}

osu.Game/Overlays/Settings/Sections/Gameplay/BackgroundSettings.cs

@@ -0,0 +1,48 @@
+// 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.
+
+using osu.Framework.Allocation;
+using osu.Framework.Graphics;
+using osu.Framework.Localisation;
+using osu.Game.Configuration;
+using osu.Game.Localisation;
+
+namespace osu.Game.Overlays.Settings.Sections.Gameplay
+{
+    public class BackgroundSettings : SettingsSubsection
+    {
+        protected override LocalisableString Header => GameplaySettingsStrings.BackgroundHeader;
+
+        [BackgroundDependencyLoader]
+        private void load(OsuConfigManager config)
+        {
+            Children = new Drawable[]
+            {
+                new SettingsSlider<double>
+                {
+                    LabelText = GameplaySettingsStrings.BackgroundDim,
+                    Current = config.GetBindable<double>(OsuSetting.DimLevel),
+                    KeyboardStep = 0.01f,
+                    DisplayAsPercentage = true
+                },
+                new SettingsSlider<double>
+                {
+                    LabelText = GameplaySettingsStrings.BackgroundBlur,
+                    Current = config.GetBindable<double>(OsuSetting.BlurLevel),
+                    KeyboardStep = 0.01f,
+                    DisplayAsPercentage = true
+                },
+                new SettingsCheckbox
+                {
+                    LabelText = GameplaySettingsStrings.LightenDuringBreaks,
+                    Current = config.GetBindable<bool>(OsuSetting.LightenDuringBreaks)
+                },
+                new SettingsCheckbox
+                {
+                    LabelText = GameplaySettingsStrings.FadePlayfieldWhenHealthLow,
+                    Current = config.GetBindable<bool>(OsuSetting.FadePlayfieldWhenHealthLow),
+                },
+            };
+        }
+    }
+}

osu.Game/Overlays/Settings/Sections/Gameplay/BeatmapSettings.cs

@@ -0,0 +1,44 @@
+// 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.
+
+using osu.Framework.Allocation;
+using osu.Framework.Graphics;
+using osu.Framework.Localisation;
+using osu.Game.Configuration;
+using osu.Game.Localisation;
+
+namespace osu.Game.Overlays.Settings.Sections.Gameplay
+{
+    public class BeatmapSettings : SettingsSubsection
+    {
+        protected override LocalisableString Header => GameplaySettingsStrings.BeatmapHeader;
+
+        [BackgroundDependencyLoader]
+        private void load(OsuConfigManager config)
+        {
+            Children = new Drawable[]
+            {
+                new SettingsCheckbox
+                {
+                    LabelText = SkinSettingsStrings.BeatmapSkins,
+                    Current = config.GetBindable<bool>(OsuSetting.BeatmapSkins)
+                },
+                new SettingsCheckbox
+                {
+                    LabelText = SkinSettingsStrings.BeatmapColours,
+                    Current = config.GetBindable<bool>(OsuSetting.BeatmapColours)
+                },
+                new SettingsCheckbox
+                {
+                    LabelText = SkinSettingsStrings.BeatmapHitsounds,
+                    Current = config.GetBindable<bool>(OsuSetting.BeatmapHitsounds)
+                },
+                new SettingsCheckbox
+                {
+                    LabelText = GraphicsSettingsStrings.StoryboardVideo,
+                    Current = config.GetBindable<bool>(OsuSetting.ShowStoryboard)
+                },
+            };
+        }
+    }
+}

osu.Game/Overlays/Settings/Sections/Gameplay/GeneralSettings.cs

@@ -1,7 +1,6 @@
-// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// 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.
 
-using osu.Framework;
 using osu.Framework.Allocation;
 using osu.Framework.Graphics;
 using osu.Framework.Localisation;
@@ -20,77 +19,18 @@ namespace osu.Game.Overlays.Settings.Sections.Gameplay
         {
             Children = new Drawable[]
             {
-                new SettingsSlider<double>
-                {
-                    LabelText = GameplaySettingsStrings.BackgroundDim,
-                    Current = config.GetBindable<double>(OsuSetting.DimLevel),
-                    KeyboardStep = 0.01f,
-                    DisplayAsPercentage = true
-                },
-                new SettingsSlider<double>
-                {
-                    LabelText = GameplaySettingsStrings.BackgroundBlur,
-                    Current = config.GetBindable<double>(OsuSetting.BlurLevel),
-                    KeyboardStep = 0.01f,
-                    DisplayAsPercentage = true
-                },
-                new SettingsCheckbox
-                {
-                    LabelText = GameplaySettingsStrings.LightenDuringBreaks,
-                    Current = config.GetBindable<bool>(OsuSetting.LightenDuringBreaks)
-                },
-                new SettingsEnumDropdown<HUDVisibilityMode>
-                {
-                    LabelText = GameplaySettingsStrings.HUDVisibilityMode,
-                    Current = config.GetBindable<HUDVisibilityMode>(OsuSetting.HUDVisibilityMode)
-                },
-                new SettingsCheckbox
-                {
-                    LabelText = GameplaySettingsStrings.ShowDifficultyGraph,
-                    Current = config.GetBindable<bool>(OsuSetting.ShowProgressGraph)
-                },
-                new SettingsCheckbox
-                {
-                    LabelText = GameplaySettingsStrings.ShowHealthDisplayWhenCantFail,
-                    Current = config.GetBindable<bool>(OsuSetting.ShowHealthDisplayWhenCantFail),
-                    Keywords = new[] { "hp", "bar" }
-                },
-                new SettingsCheckbox
-                {
-                    LabelText = GameplaySettingsStrings.FadePlayfieldWhenHealthLow,
-                    Current = config.GetBindable<bool>(OsuSetting.FadePlayfieldWhenHealthLow),
-                },
-                new SettingsCheckbox
-                {
-                    LabelText = GameplaySettingsStrings.AlwaysShowKeyOverlay,
-                    Current = config.GetBindable<bool>(OsuSetting.KeyOverlay)
-                },
-                new SettingsCheckbox
-                {
-                    LabelText = GameplaySettingsStrings.PositionalHitsounds,
-                    Current = config.GetBindable<bool>(OsuSetting.PositionalHitSounds)
-                },
-                new SettingsCheckbox
-                {
-                    LabelText = GameplaySettingsStrings.AlwaysPlayFirstComboBreak,
-                    Current = config.GetBindable<bool>(OsuSetting.AlwaysPlayFirstComboBreak)
-                },
                 new SettingsEnumDropdown<ScoringMode>
                 {
                     LabelText = GameplaySettingsStrings.ScoreDisplayMode,
                     Current = config.GetBindable<ScoringMode>(OsuSetting.ScoreDisplayMode),
                     Keywords = new[] { "scoring" }
                 },
-            };
-
-            if (RuntimeInfo.OS == RuntimeInfo.Platform.Windows)
-            {
-                Add(new SettingsCheckbox
+                new SettingsCheckbox
                 {
-                    LabelText = GameplaySettingsStrings.DisableWinKey,
-                    Current = config.GetBindable<bool>(OsuSetting.GameplayDisableWinKey)
-                });
-            }
+                    LabelText = GraphicsSettingsStrings.HitLighting,
+                    Current = config.GetBindable<bool>(OsuSetting.HitLighting)
+                },
+            };
         }
     }
 }

osu.Game/Overlays/Settings/Sections/Gameplay/HUDSettings.cs

@@ -0,0 +1,45 @@
+// 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.
+
+using osu.Framework.Allocation;
+using osu.Framework.Graphics;
+using osu.Framework.Localisation;
+using osu.Game.Configuration;
+using osu.Game.Localisation;
+
+namespace osu.Game.Overlays.Settings.Sections.Gameplay
+{
+    public class HUDSettings : SettingsSubsection
+    {
+        protected override LocalisableString Header => GameplaySettingsStrings.HUDHeader;
+
+        [BackgroundDependencyLoader]
+        private void load(OsuConfigManager config)
+        {
+            Children = new Drawable[]
+            {
+                new SettingsEnumDropdown<HUDVisibilityMode>
+                {
+                    LabelText = GameplaySettingsStrings.HUDVisibilityMode,
+                    Current = config.GetBindable<HUDVisibilityMode>(OsuSetting.HUDVisibilityMode)
+                },
+                new SettingsCheckbox
+                {
+                    LabelText = GameplaySettingsStrings.ShowDifficultyGraph,
+                    Current = config.GetBindable<bool>(OsuSetting.ShowProgressGraph)
+                },
+                new SettingsCheckbox
+                {
+                    LabelText = GameplaySettingsStrings.ShowHealthDisplayWhenCantFail,
+                    Current = config.GetBindable<bool>(OsuSetting.ShowHealthDisplayWhenCantFail),
+                    Keywords = new[] { "hp", "bar" }
+                },
+                new SettingsCheckbox
+                {
+                    LabelText = GameplaySettingsStrings.AlwaysShowKeyOverlay,
+                    Current = config.GetBindable<bool>(OsuSetting.KeyOverlay)
+                },
+            };
+        }
+    }
+}

osu.Game/Overlays/Settings/Sections/Gameplay/InputSettings.cs

@@ -0,0 +1,45 @@
+// 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.
+
+using osu.Framework;
+using osu.Framework.Allocation;
+using osu.Framework.Graphics;
+using osu.Framework.Localisation;
+using osu.Game.Configuration;
+using osu.Game.Localisation;
+
+namespace osu.Game.Overlays.Settings.Sections.Gameplay
+{
+    public class InputSettings : SettingsSubsection
+    {
+        protected override LocalisableString Header => GameplaySettingsStrings.InputHeader;
+
+        [BackgroundDependencyLoader]
+        private void load(OsuConfigManager config)
+        {
+            Children = new Drawable[]
+            {
+                new SettingsSlider<float, SizeSlider>
+                {
+                    LabelText = SkinSettingsStrings.GameplayCursorSize,
+                    Current = config.GetBindable<float>(OsuSetting.GameplayCursorSize),
+                    KeyboardStep = 0.01f
+                },
+                new SettingsCheckbox
+                {
+                    LabelText = SkinSettingsStrings.AutoCursorSize,
+                    Current = config.GetBindable<bool>(OsuSetting.AutoCursorSize)
+                },
+            };
+
+            if (RuntimeInfo.OS == RuntimeInfo.Platform.Windows)
+            {
+                Add(new SettingsCheckbox
+                {
+                    LabelText = GameplaySettingsStrings.DisableWinKey,
+                    Current = config.GetBindable<bool>(OsuSetting.GameplayDisableWinKey)
+                });
+            }
+        }
+    }
+}

osu.Game/Overlays/Settings/Sections/GameplaySection.cs

@@ -1,16 +1,11 @@
 // 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.
 
-using System;
-using osu.Framework.Allocation;
 using osu.Framework.Graphics;
-using osu.Game.Overlays.Settings.Sections.Gameplay;
-using osu.Game.Rulesets;
-using System.Linq;
 using osu.Framework.Graphics.Sprites;
-using osu.Framework.Logging;
 using osu.Framework.Localisation;
 using osu.Game.Localisation;
+using osu.Game.Overlays.Settings.Sections.Gameplay;
 
 namespace osu.Game.Overlays.Settings.Sections
 {
@@ -20,7 +15,7 @@ namespace osu.Game.Overlays.Settings.Sections
 
         public override Drawable CreateIcon() => new SpriteIcon
         {
-            Icon = FontAwesome.Regular.Circle
+            Icon = FontAwesome.Regular.DotCircle
         };
 
         public GameplaySection()
@@ -28,27 +23,13 @@ namespace osu.Game.Overlays.Settings.Sections
             Children = new Drawable[]
             {
                 new GeneralSettings(),
+                new AudioSettings(),
+                new BeatmapSettings(),
+                new BackgroundSettings(),
+                new HUDSettings(),
+                new InputSettings(),
                 new ModsSettings(),
             };
         }
-
-        [BackgroundDependencyLoader]
-        private void load(RulesetStore rulesets)
-        {
-            foreach (Ruleset ruleset in rulesets.AvailableRulesets.Select(info => info.CreateInstance()))
-            {
-                try
-                {
-                    SettingsSubsection section = ruleset.CreateSettings();
-
-                    if (section != null)
-                        Add(section);
-                }
-                catch (Exception e)
-                {
-                    Logger.Error(e, "Failed to load ruleset settings");
-                }
-            }
-        }
     }
 }

osu.Game/Overlays/Settings/Sections/Graphics/ScreenshotSettings.cs

@@ -9,25 +9,15 @@ using osu.Game.Localisation;
 
 namespace osu.Game.Overlays.Settings.Sections.Graphics
 {
-    public class DetailSettings : SettingsSubsection
+    public class ScreenshotSettings : SettingsSubsection
     {
-        protected override LocalisableString Header => GraphicsSettingsStrings.DetailSettingsHeader;
+        protected override LocalisableString Header => GraphicsSettingsStrings.Screenshots;
 
         [BackgroundDependencyLoader]
         private void load(OsuConfigManager config)
         {
             Children = new Drawable[]
             {
-                new SettingsCheckbox
-                {
-                    LabelText = GraphicsSettingsStrings.StoryboardVideo,
-                    Current = config.GetBindable<bool>(OsuSetting.ShowStoryboard)
-                },
-                new SettingsCheckbox
-                {
-                    LabelText = GraphicsSettingsStrings.HitLighting,
-                    Current = config.GetBindable<bool>(OsuSetting.HitLighting)
-                },
                 new SettingsEnumDropdown<ScreenshotFormat>
                 {
                     LabelText = GraphicsSettingsStrings.ScreenshotFormat,

osu.Game/Overlays/Settings/Sections/GraphicsSection.cs

@@ -22,9 +22,9 @@ namespace osu.Game.Overlays.Settings.Sections
         {
             Children = new Drawable[]
             {
-                new RendererSettings(),
                 new LayoutSettings(),
-                new DetailSettings(),
+                new RendererSettings(),
+                new ScreenshotSettings(),
             };
         }
     }

osu.Game/Overlays/Settings/Sections/RulesetSection.cs

@@ -0,0 +1,44 @@
+// 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.
+
+using System;
+using System.Linq;
+using osu.Framework.Allocation;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Sprites;
+using osu.Framework.Localisation;
+using osu.Framework.Logging;
+using osu.Game.Rulesets;
+using osu.Game.Localisation;
+
+namespace osu.Game.Overlays.Settings.Sections
+{
+    public class RulesetSection : SettingsSection
+    {
+        public override LocalisableString Header => RulesetSettingsStrings.Rulesets;
+
+        public override Drawable CreateIcon() => new SpriteIcon
+        {
+            Icon = FontAwesome.Solid.Chess
+        };
+
+        [BackgroundDependencyLoader]
+        private void load(RulesetStore rulesets)
+        {
+            foreach (Ruleset ruleset in rulesets.AvailableRulesets.Select(info => info.CreateInstance()))
+            {
+                try
+                {
+                    SettingsSubsection section = ruleset.CreateSettings();
+
+                    if (section != null)
+                        Add(section);
+                }
+                catch (Exception e)
+                {
+                    Logger.Error(e, "Failed to load ruleset settings");
+                }
+            }
+        }
+    }
+}

osu.Game/Overlays/Settings/Sections/SkinSection.cs

@@ -64,39 +64,16 @@ namespace osu.Game.Overlays.Settings.Sections
         {
             Children = new Drawable[]
             {
-                skinDropdown = new SkinSettingsDropdown(),
+                skinDropdown = new SkinSettingsDropdown
+                {
+                    LabelText = SkinSettingsStrings.CurrentSkin
+                },
                 new SettingsButton
                 {
                     Text = SkinSettingsStrings.SkinLayoutEditor,
                     Action = () => skinEditor?.Toggle(),
                 },
                 new ExportSkinButton(),
-                new SettingsSlider<float, SizeSlider>
-                {
-                    LabelText = SkinSettingsStrings.GameplayCursorSize,
-                    Current = config.GetBindable<float>(OsuSetting.GameplayCursorSize),
-                    KeyboardStep = 0.01f
-                },
-                new SettingsCheckbox
-                {
-                    LabelText = SkinSettingsStrings.AutoCursorSize,
-                    Current = config.GetBindable<bool>(OsuSetting.AutoCursorSize)
-                },
-                new SettingsCheckbox
-                {
-                    LabelText = SkinSettingsStrings.BeatmapSkins,
-                    Current = config.GetBindable<bool>(OsuSetting.BeatmapSkins)
-                },
-                new SettingsCheckbox
-                {
-                    LabelText = SkinSettingsStrings.BeatmapColours,
-                    Current = config.GetBindable<bool>(OsuSetting.BeatmapColours)
-                },
-                new SettingsCheckbox
-                {
-                    LabelText = SkinSettingsStrings.BeatmapHitsounds,
-                    Current = config.GetBindable<bool>(OsuSetting.BeatmapHitsounds)
-                },
             };
 
             managerUpdated = skins.ItemUpdated.GetBoundCopy();

osu.Game/Overlays/SettingsOverlay.cs

@@ -24,12 +24,13 @@ namespace osu.Game.Overlays
         protected override IEnumerable<SettingsSection> CreateSections() => new SettingsSection[]
         {
             new GeneralSection(),
-            new GraphicsSection(),
-            new AudioSection(),
+            new SkinSection(),
             new InputSection(createSubPanel(new KeyBindingPanel())),
             new UserInterfaceSection(),
             new GameplaySection(),
-            new SkinSection(),
+            new RulesetSection(),
+            new AudioSection(),
+            new GraphicsSection(),
             new OnlineSection(),
             new MaintenanceSection(),
             new DebugSection(),

osu.Game/Rulesets/UI/FrameStabilityContainer.cs

@@ -55,7 +55,10 @@ namespace osu.Game.Rulesets.UI
         /// <summary>
         /// The current direction of playback to be exposed to frame stable children.
         /// </summary>
-        private int direction;
+        /// <remarks>
+        /// Initially it is presumed that playback will proceed in the forward direction.
+        /// </remarks>
+        private int direction = 1;
 
         [BackgroundDependencyLoader(true)]
         private void load(GameplayClock clock, ISamplePlaybackDisabler sampleDisabler)
@@ -139,7 +142,9 @@ namespace osu.Game.Rulesets.UI
                     state = PlaybackState.NotValid;
             }
 
-            if (state == PlaybackState.Valid)
+            // if the proposed time is the same as the current time, assume that the clock will continue progressing in the same direction as previously.
+            // this avoids spurious flips in direction from -1 to 1 during rewinds.
+            if (state == PlaybackState.Valid && proposedTime != manualClock.CurrentTime)
                 direction = proposedTime >= manualClock.CurrentTime ? 1 : -1;
 
             double timeBehind = Math.Abs(proposedTime - parentGameplayClock.CurrentTime);

osu.Game/Screens/Play/FailAnimation.cs

@@ -22,7 +22,7 @@ namespace osu.Game.Screens.Play
 {
     /// <summary>
     /// Manage the animation to be applied when a player fails.
-    /// Single file; automatically disposed after use.
+    /// Single use and automatically disposed after use.
     /// </summary>
     public class FailAnimation : CompositeDrawable
     {

osu.Game/Screens/Play/Player.cs

@@ -947,7 +947,7 @@ namespace osu.Game.Screens.Play
 
         public override void OnSuspending(IScreen next)
         {
-            screenSuspension?.Expire();
+            screenSuspension?.RemoveAndDisposeImmediately();
 
             fadeOut();
             base.OnSuspending(next);
@@ -955,7 +955,8 @@ namespace osu.Game.Screens.Play
 
         public override bool OnExiting(IScreen next)
         {
-            screenSuspension?.Expire();
+            screenSuspension?.RemoveAndDisposeImmediately();
+            failAnimation?.RemoveAndDisposeImmediately();
 
             // if arriving here and the results screen preparation task hasn't run, it's safe to say the user has not completed the beatmap.
             if (prepareScoreForDisplayTask == null)

osu.Game/Screens/Play/PlayerLoader.cs

@@ -35,6 +35,8 @@ namespace osu.Game.Screens.Play
     {
         protected const float BACKGROUND_BLUR = 15;
 
+        private const double content_out_duration = 300;
+
         public override bool HideOverlaysOnEnter => hideOverlays;
 
         public override bool DisallowExternalBeatmapRulesetChanges => true;
@@ -135,36 +137,39 @@ namespace osu.Game.Screens.Play
             muteWarningShownOnce = sessionStatics.GetBindable<bool>(Static.MutedAudioNotificationShownOnce);
             batteryWarningShownOnce = sessionStatics.GetBindable<bool>(Static.LowBatteryNotificationShownOnce);
 
-            InternalChild = (content = new LogoTrackingContainer
+            InternalChildren = new Drawable[]
             {
-                Anchor = Anchor.Centre,
-                Origin = Anchor.Centre,
-                RelativeSizeAxes = Axes.Both,
-            }).WithChildren(new Drawable[]
-            {
-                MetadataInfo = new BeatmapMetadataDisplay(Beatmap.Value, Mods, content.LogoFacade)
+                (content = new LogoTrackingContainer
                 {
-                    Alpha = 0,
                     Anchor = Anchor.Centre,
                     Origin = Anchor.Centre,
-                },
-                PlayerSettings = new FillFlowContainer<PlayerSettingsGroup>
+                    RelativeSizeAxes = Axes.Both,
+                }).WithChildren(new Drawable[]
                 {
-                    Anchor = Anchor.TopRight,
-                    Origin = Anchor.TopRight,
-                    AutoSizeAxes = Axes.Both,
-                    Direction = FillDirection.Vertical,
-                    Spacing = new Vector2(0, 20),
-                    Margin = new MarginPadding(25),
-                    Children = new PlayerSettingsGroup[]
+                    MetadataInfo = new BeatmapMetadataDisplay(Beatmap.Value, Mods, content.LogoFacade)
                     {
-                        VisualSettings = new VisualSettings(),
-                        new InputSettings()
-                    }
-                },
-                idleTracker = new IdleTracker(750),
+                        Alpha = 0,
+                        Anchor = Anchor.Centre,
+                        Origin = Anchor.Centre,
+                    },
+                    PlayerSettings = new FillFlowContainer<PlayerSettingsGroup>
+                    {
+                        Anchor = Anchor.TopRight,
+                        Origin = Anchor.TopRight,
+                        AutoSizeAxes = Axes.Both,
+                        Direction = FillDirection.Vertical,
+                        Spacing = new Vector2(0, 20),
+                        Margin = new MarginPadding(25),
+                        Children = new PlayerSettingsGroup[]
+                        {
+                            VisualSettings = new VisualSettings(),
+                            new InputSettings()
+                        }
+                    },
+                    idleTracker = new IdleTracker(750),
+                }),
                 lowPassFilter = new AudioFilter(audio.TrackMixer)
-            });
+            };
 
             if (Beatmap.Value.BeatmapInfo.EpilepsyWarning)
             {
@@ -195,7 +200,6 @@ namespace osu.Game.Screens.Play
                     epilepsyWarning.DimmableBackground = b;
             });
 
-            lowPassFilter.CutoffTo(500, 100, Easing.OutCubic);
             Beatmap.Value.Track.AddAdjustment(AdjustableProperty.Volume, volumeAdjustment);
 
             content.ScaleTo(0.7f);
@@ -240,15 +244,15 @@ namespace osu.Game.Screens.Play
         public override bool OnExiting(IScreen next)
         {
             cancelLoad();
+            contentOut();
 
-            content.ScaleTo(0.7f, 150, Easing.InQuint);
-            this.FadeOut(150);
+            // Ensure the screen doesn't expire until all the outwards fade operations have completed.
+            this.Delay(content_out_duration).FadeOut();
 
             ApplyToBackground(b => b.IgnoreUserSettings.Value = true);
 
             BackgroundBrightnessReduction = false;
             Beatmap.Value.Track.RemoveAdjustment(AdjustableProperty.Volume, volumeAdjustment);
-            lowPassFilter.CutoffTo(AudioFilter.MAX_LOWPASS_CUTOFF, 100, Easing.InCubic);
 
             return base.OnExiting(next);
         }
@@ -344,6 +348,7 @@ namespace osu.Game.Screens.Play
 
             content.FadeInFromZero(400);
             content.ScaleTo(1, 650, Easing.OutQuint).Then().Schedule(prepareNewPlayer);
+            lowPassFilter.CutoffTo(1000, 650, Easing.OutQuint);
 
             ApplyToBackground(b => b?.FadeColour(Color4.White, 800, Easing.OutQuint));
         }
@@ -353,8 +358,9 @@ namespace osu.Game.Screens.Play
             // Ensure the logo is no longer tracking before we scale the content
             content.StopTracking();
 
-            content.ScaleTo(0.7f, 300, Easing.InQuint);
-            content.FadeOut(250);
+            content.ScaleTo(0.7f, content_out_duration * 2, Easing.OutQuint);
+            content.FadeOut(content_out_duration, Easing.OutQuint);
+            lowPassFilter.CutoffTo(AudioFilter.MAX_LOWPASS_CUTOFF, content_out_duration);
         }
 
         private void pushWhenLoaded()
@@ -381,7 +387,7 @@ namespace osu.Game.Screens.Play
 
                 contentOut();
 
-                TransformSequence<PlayerLoader> pushSequence = this.Delay(250);
+                TransformSequence<PlayerLoader> pushSequence = this.Delay(content_out_duration);
 
                 // only show if the warning was created (i.e. the beatmap needs it)
                 // and this is not a restart of the map (the warning expires after first load).
@@ -400,6 +406,11 @@ namespace osu.Game.Screens.Play
                         })
                         .Delay(EpilepsyWarning.FADE_DURATION);
                 }
+                else
+                {
+                    // This goes hand-in-hand with the restoration of low pass filter in contentOut().
+                    this.TransformBindableTo(volumeAdjustment, 0, content_out_duration, Easing.OutCubic);
+                }
 
                 pushSequence.Schedule(() =>
                 {

osu.Game/Skinning/ISkinSource.cs

@@ -12,6 +12,9 @@ namespace osu.Game.Skinning
     /// </summary>
     public interface ISkinSource : ISkin
     {
+        /// <summary>
+        /// Fired whenever a source change occurs, signalling that consumers should re-query as required.
+        /// </summary>
         event Action SourceChanged;
 
         /// <summary>

osu.Game/Skinning/RulesetSkinProvidingContainer.cs

@@ -58,10 +58,8 @@ namespace osu.Game.Skinning
             return base.CreateChildDependencies(parent);
         }
 
-        protected override void OnSourceChanged()
+        protected override void RefreshSources()
         {
-            ResetSources();
-
             // Populate a local list first so we can adjust the returned order as we go.
             var sources = new List<ISkin>();
 
@@ -91,8 +89,7 @@ namespace osu.Game.Skinning
             else
                 sources.Add(rulesetResourcesSkin);
 
-            foreach (var skin in sources)
-                AddSource(skin);
+            SetSources(sources);
         }
 
         protected ISkin GetLegacyRulesetTransformedSkin(ISkin legacySkin)

osu.Game/Skinning/SkinProvidingContainer.cs

@@ -3,6 +3,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using JetBrains.Annotations;
 using osu.Framework.Allocation;
 using osu.Framework.Audio.Sample;
@@ -40,10 +41,12 @@ namespace osu.Game.Skinning
 
         protected virtual bool AllowColourLookup => true;
 
+        private readonly object sourceSetLock = new object();
+
         /// <summary>
         /// A dictionary mapping each <see cref="ISkin"/> source to a wrapper which handles lookup allowances.
         /// </summary>
-        private readonly List<(ISkin skin, DisableableSkinSource wrapped)> skinSources = new List<(ISkin, DisableableSkinSource)>();
+        private (ISkin skin, DisableableSkinSource wrapped)[] skinSources = Array.Empty<(ISkin skin, DisableableSkinSource wrapped)>();
 
         /// <summary>
         /// Constructs a new <see cref="SkinProvidingContainer"/> initialised with a single skin source.
@@ -52,7 +55,7 @@ namespace osu.Game.Skinning
             : this()
         {
             if (skin != null)
-                AddSource(skin);
+                SetSources(new[] { skin });
         }
 
         /// <summary>
@@ -168,49 +171,42 @@ namespace osu.Game.Skinning
         }
 
         /// <summary>
-        /// Add a new skin to this provider. Will be added to the end of the lookup order precedence.
+        /// Replace the sources used for lookups in this container.
         /// </summary>
-        /// <param name="skin">The skin to add.</param>
-        protected void AddSource(ISkin skin)
+        /// <remarks>
+        /// This does not implicitly fire a <see cref="SourceChanged"/> event. Consider calling <see cref="TriggerSourceChanged"/> if required.
+        /// </remarks>
+        /// <param name="sources">The new sources.</param>
+        protected void SetSources(IEnumerable<ISkin> sources)
         {
-            skinSources.Add((skin, new DisableableSkinSource(skin, this)));
+            lock (sourceSetLock)
+            {
+                foreach (var skin in skinSources)
+                {
+                    if (skin.skin is ISkinSource source)
+                        source.SourceChanged -= TriggerSourceChanged;
+                }
 
-            if (skin is ISkinSource source)
-                source.SourceChanged += TriggerSourceChanged;
+                skinSources = sources.Select(skin => (skin, new DisableableSkinSource(skin, this))).ToArray();
+
+                foreach (var skin in skinSources)
+                {
+                    if (skin.skin is ISkinSource source)
+                        source.SourceChanged += TriggerSourceChanged;
+                }
+            }
         }
 
         /// <summary>
-        /// Remove a skin from this provider.
-        /// </summary>
-        /// <param name="skin">The skin to remove.</param>
-        protected void RemoveSource(ISkin skin)
-        {
-            if (skinSources.RemoveAll(s => s.skin == skin) == 0)
-                return;
-
-            if (skin is ISkinSource source)
-                source.SourceChanged -= TriggerSourceChanged;
-        }
-
-        /// <summary>
-        /// Clears all skin sources.
-        /// </summary>
-        protected void ResetSources()
-        {
-            foreach (var i in skinSources.ToArray())
-                RemoveSource(i.skin);
-        }
-
-        /// <summary>
-        /// Invoked when any source has changed (either <see cref="ParentSource"/> or a source registered via <see cref="AddSource"/>).
+        /// Invoked after any consumed source change, before the external <see cref="SourceChanged"/> event is fired.
         /// This is also invoked once initially during <see cref="CreateChildDependencies"/> to ensure sources are ready for children consumption.
         /// </summary>
-        protected virtual void OnSourceChanged() { }
+        protected virtual void RefreshSources() { }
 
         protected void TriggerSourceChanged()
         {
             // Expose to implementations, giving them a chance to react before notifying external consumers.
-            OnSourceChanged();
+            RefreshSources();
 
             SourceChanged?.Invoke();
         }

osu.Game/Stores/RealmFileStore.cs

@@ -0,0 +1,116 @@
+// 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.
+
+using System;
+using System.IO;
+using System.Linq;
+using osu.Framework.Extensions;
+using osu.Framework.IO.Stores;
+using osu.Framework.Logging;
+using osu.Framework.Platform;
+using osu.Framework.Testing;
+using osu.Game.Database;
+using osu.Game.Models;
+using Realms;
+
+#nullable enable
+
+namespace osu.Game.Stores
+{
+    /// <summary>
+    /// Handles the storing of files to the file system (and database) backing.
+    /// </summary>
+    [ExcludeFromDynamicCompile]
+    public class RealmFileStore
+    {
+        private readonly RealmContextFactory realmFactory;
+
+        public readonly IResourceStore<byte[]> Store;
+
+        public readonly Storage Storage;
+
+        public RealmFileStore(RealmContextFactory realmFactory, Storage storage)
+        {
+            this.realmFactory = realmFactory;
+
+            Storage = storage.GetStorageForDirectory(@"files");
+            Store = new StorageBackedResourceStore(Storage);
+        }
+
+        /// <summary>
+        /// Add a new file to the game-wide database, copying it to permanent storage if not already present.
+        /// </summary>
+        /// <param name="data">The file data stream.</param>
+        /// <param name="realm">The realm instance to add to. Should already be in a transaction.</param>
+        /// <returns></returns>
+        public RealmFile Add(Stream data, Realm realm)
+        {
+            string hash = data.ComputeSHA2Hash();
+
+            var existing = realm.Find<RealmFile>(hash);
+
+            var file = existing ?? new RealmFile { Hash = hash };
+
+            if (!checkFileExistsAndMatchesHash(file))
+                copyToStore(file, data);
+
+            if (!file.IsManaged)
+                realm.Add(file);
+
+            return file;
+        }
+
+        private void copyToStore(RealmFile file, Stream data)
+        {
+            data.Seek(0, SeekOrigin.Begin);
+
+            using (var output = Storage.GetStream(file.StoragePath, FileAccess.Write))
+                data.CopyTo(output);
+
+            data.Seek(0, SeekOrigin.Begin);
+        }
+
+        private bool checkFileExistsAndMatchesHash(RealmFile file)
+        {
+            string path = file.StoragePath;
+
+            // we may be re-adding a file to fix missing store entries.
+            if (!Storage.Exists(path))
+                return false;
+
+            // even if the file already exists, check the existing checksum for safety.
+            using (var stream = Storage.GetStream(path))
+                return stream.ComputeSHA2Hash() == file.Hash;
+        }
+
+        public void Cleanup()
+        {
+            var realm = realmFactory.Context;
+
+            // can potentially be run asynchronously, although we will need to consider operation order for disk deletion vs realm removal.
+            using (var transaction = realm.BeginWrite())
+            {
+                // TODO: consider using a realm native query to avoid iterating all files (https://github.com/realm/realm-dotnet/issues/2659#issuecomment-927823707)
+                var files = realm.All<RealmFile>().ToList();
+
+                foreach (var file in files)
+                {
+                    if (file.BacklinksCount > 0)
+                        continue;
+
+                    try
+                    {
+                        Storage.Delete(file.StoragePath);
+                        realm.Remove(file);
+                    }
+                    catch (Exception e)
+                    {
+                        Logger.Error(e, $@"Could not delete databased file {file.Hash}");
+                    }
+                }
+
+                transaction.Commit();
+            }
+        }
+    }
+}

osu.Game/Tests/Beatmaps/BeatmapConversionTest.cs

@@ -14,6 +14,7 @@ using osu.Framework.Graphics.Textures;
 using osu.Game.Beatmaps;
 using osu.Game.Beatmaps.Formats;
 using osu.Game.IO;
+using osu.Game.IO.Serialization;
 using osu.Game.Rulesets;
 using osu.Game.Rulesets.Mods;
 using osu.Game.Rulesets.Objects;
@@ -109,6 +110,8 @@ namespace osu.Game.Tests.Beatmaps
         {
             var beatmap = GetBeatmap(name);
 
+            string beforeConversion = beatmap.Serialize();
+
             var converterResult = new Dictionary<HitObject, IEnumerable<HitObject>>();
 
             var working = new ConversionWorkingBeatmap(beatmap)
@@ -122,6 +125,10 @@ namespace osu.Game.Tests.Beatmaps
 
             working.GetPlayableBeatmap(CreateRuleset().RulesetInfo, mods);
 
+            string afterConversion = beatmap.Serialize();
+
+            Assert.AreEqual(beforeConversion, afterConversion, "Conversion altered original beatmap");
+
             return new ConvertResult
             {
                 Mappings = converterResult.Select(r =>

osu.Game/Tests/Visual/OsuGameTestScene.cs

@@ -78,9 +78,11 @@ namespace osu.Game.Tests.Visual
 
         protected void CreateGame()
         {
-            AddGame(Game = new TestOsuGame(LocalStorage, API));
+            AddGame(Game = CreateTestGame());
         }
 
+        protected virtual TestOsuGame CreateTestGame() => new TestOsuGame(LocalStorage, API);
+
         protected void PushAndConfirm(Func<Screen> newScreen)
         {
             Screen screen = null;
@@ -135,7 +137,8 @@ namespace osu.Game.Tests.Visual
 
             public new void PerformFromScreen(Action<IScreen> action, IEnumerable<Type> validScreens = null) => base.PerformFromScreen(action, validScreens);
 
-            public TestOsuGame(Storage storage, IAPIProvider api)
+            public TestOsuGame(Storage storage, IAPIProvider api, string[] args = null)
+                : base(args)
             {
                 Storage = storage;
                 API = api;

osu.Game/osu.Game.csproj

@@ -36,7 +36,7 @@
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageReference>
     <PackageReference Include="Realm" Version="10.6.0" />
-    <PackageReference Include="ppy.osu.Framework" Version="2021.1004.0" />
+    <PackageReference Include="ppy.osu.Framework" Version="2021.1012.0" />
     <PackageReference Include="ppy.osu.Game.Resources" Version="2021.1004.0" />
     <PackageReference Include="Sentry" Version="3.9.4" />
     <PackageReference Include="SharpCompress" Version="0.29.0" />

osu.iOS.props

@@ -70,7 +70,7 @@
     <Reference Include="System.Net.Http" />
   </ItemGroup>
   <ItemGroup Label="Package References">
-    <PackageReference Include="ppy.osu.Framework.iOS" Version="2021.1004.0" />
+    <PackageReference Include="ppy.osu.Framework.iOS" Version="2021.1012.0" />
     <PackageReference Include="ppy.osu.Game.Resources" Version="2021.1004.0" />
   </ItemGroup>
   <!-- See https://github.com/dotnet/runtime/issues/35988 (can be removed after Xamarin uses net5.0 / net6.0) -->
@@ -93,7 +93,7 @@
     <PackageReference Include="Microsoft.EntityFrameworkCore.Sqlite" Version="2.2.6" />
     <PackageReference Include="Microsoft.EntityFrameworkCore.Sqlite.Core" Version="2.2.6" />
     <PackageReference Include="Newtonsoft.Json" Version="13.0.1" />
-    <PackageReference Include="ppy.osu.Framework" Version="2021.1004.0" />
+    <PackageReference Include="ppy.osu.Framework" Version="2021.1012.0" />
     <PackageReference Include="SharpCompress" Version="0.28.3" />
     <PackageReference Include="NUnit" Version="3.13.2" />
     <PackageReference Include="SharpRaven" Version="2.4.0" />