Merge pull request #28800 from peppy/file-mounting-v3

Add ability to edit beatmap content externally

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

@@ -1,6 +1,7 @@
 // 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 System.Linq;
 using NUnit.Framework;
 using osu.Framework.Extensions;
@@ -13,6 +14,7 @@ using osu.Framework.Testing;
 using osu.Game.Beatmaps;
 using osu.Game.Configuration;
 using osu.Game.Database;
+using osu.Game.Graphics.UserInterface;
 using osu.Game.Overlays;
 using osu.Game.Rulesets.Mania;
 using osu.Game.Rulesets.Osu;
@@ -29,30 +31,80 @@ namespace osu.Game.Tests.Visual.Navigation
 {
     public partial class TestSceneBeatmapEditorNavigation : OsuGameTestScene
     {
+        private BeatmapSetInfo beatmapSet = null!;
+
+        [Test]
+        public void TestExternalEditingNoChange()
+        {
+            string difficultyName = null!;
+
+            prepareBeatmap();
+            openEditor();
+
+            AddStep("store difficulty name", () => difficultyName = getEditor().Beatmap.Value.BeatmapInfo.DifficultyName);
+
+            AddStep("open file menu", () => getEditor().ChildrenOfType<Menu.DrawableMenuItem>().Single(m => m.Item.Text.Value.ToString() == "File").TriggerClick());
+            AddStep("click external edit", () => getEditor().ChildrenOfType<Menu.DrawableMenuItem>().Single(m => m.Item.Text.Value.ToString() == "Edit externally").TriggerClick());
+
+            AddUntilStep("wait for external edit screen", () => Game.ScreenStack.CurrentScreen is ExternalEditScreen externalEditScreen && externalEditScreen.IsLoaded);
+
+            AddUntilStep("wait for button ready", () => ((ExternalEditScreen)Game.ScreenStack.CurrentScreen).ChildrenOfType<DangerousRoundedButton>().FirstOrDefault()?.Enabled.Value == true);
+
+            AddStep("finish external edit", () => ((ExternalEditScreen)Game.ScreenStack.CurrentScreen).ChildrenOfType<DangerousRoundedButton>().First().TriggerClick());
+
+            AddUntilStep("wait for editor", () => Game.ScreenStack.CurrentScreen is Editor editor && editor.ReadyForUse);
+
+            AddAssert("beatmapset didn't change", () => getEditor().Beatmap.Value.BeatmapSetInfo, () => Is.EqualTo(beatmapSet));
+            AddAssert("difficulty didn't change", () => getEditor().Beatmap.Value.BeatmapInfo.DifficultyName, () => Is.EqualTo(difficultyName));
+            AddAssert("old beatmapset not deleted", () => Game.BeatmapManager.QueryBeatmapSet(s => s.ID == beatmapSet.ID), () => Is.Not.Null);
+        }
+
+        [Test]
+        public void TestExternalEditingWithChange()
+        {
+            string difficultyName = null!;
+
+            prepareBeatmap();
+            openEditor();
+
+            AddStep("store difficulty name", () => difficultyName = getEditor().Beatmap.Value.BeatmapInfo.DifficultyName);
+
+            AddStep("open file menu", () => getEditor().ChildrenOfType<Menu.DrawableMenuItem>().Single(m => m.Item.Text.Value.ToString() == "File").TriggerClick());
+            AddStep("click external edit", () => getEditor().ChildrenOfType<Menu.DrawableMenuItem>().Single(m => m.Item.Text.Value.ToString() == "Edit externally").TriggerClick());
+
+            AddUntilStep("wait for external edit screen", () => Game.ScreenStack.CurrentScreen is ExternalEditScreen externalEditScreen && externalEditScreen.IsLoaded);
+
+            AddUntilStep("wait for button ready", () => ((ExternalEditScreen)Game.ScreenStack.CurrentScreen).ChildrenOfType<DangerousRoundedButton>().FirstOrDefault()?.Enabled.Value == true);
+
+            AddStep("add file externally", () =>
+            {
+                var op = ((ExternalEditScreen)Game.ScreenStack.CurrentScreen).EditOperation!;
+                File.WriteAllText(Path.Combine(op.MountedPath, "test.txt"), "test");
+            });
+
+            AddStep("finish external edit", () => ((ExternalEditScreen)Game.ScreenStack.CurrentScreen).ChildrenOfType<DangerousRoundedButton>().First().TriggerClick());
+
+            AddUntilStep("wait for editor", () => Game.ScreenStack.CurrentScreen is Editor editor && editor.ReadyForUse);
+
+            AddAssert("beatmapset changed", () => getEditor().Beatmap.Value.BeatmapSetInfo, () => Is.Not.EqualTo(beatmapSet));
+            AddAssert("beatmapset is locally modified", () => getEditor().Beatmap.Value.BeatmapSetInfo.Status, () => Is.EqualTo(BeatmapOnlineStatus.LocallyModified));
+            AddAssert("all difficulties are locally modified", () => getEditor().Beatmap.Value.BeatmapSetInfo.Beatmaps.All(b => b.Status == BeatmapOnlineStatus.LocallyModified));
+            AddAssert("difficulty didn't change", () => getEditor().Beatmap.Value.BeatmapInfo.DifficultyName, () => Is.EqualTo(difficultyName));
+            AddAssert("old beatmapset deleted", () => Game.BeatmapManager.QueryBeatmapSet(s => s.ID == beatmapSet.ID), () => Is.Null);
+        }
+
         [Test]
         public void TestSaveThenDeleteActuallyDeletesAtSongSelect()
         {
-            BeatmapSetInfo beatmapSet = null!;
+            prepareBeatmap();
-
+            openEditor();
-            AddStep("import test beatmap", () => Game.BeatmapManager.Import(TestResources.GetTestBeatmapForImport()).WaitSafely());
-            AddStep("retrieve beatmap", () => beatmapSet = Game.BeatmapManager.QueryBeatmapSet(set => !set.Protected).AsNonNull().Value.Detach());
-
-            AddStep("present beatmap", () => Game.PresentBeatmap(beatmapSet));
-            AddUntilStep("wait for song select",
-                () => Game.Beatmap.Value.BeatmapSetInfo.Equals(beatmapSet)
-                      && Game.ScreenStack.CurrentScreen is PlaySongSelect songSelect
-                      && songSelect.IsLoaded);
-
-            AddStep("open editor", () => ((PlaySongSelect)Game.ScreenStack.CurrentScreen).Edit(beatmapSet.Beatmaps.First(beatmap => beatmap.Ruleset.OnlineID == 0)));
-            AddUntilStep("wait for editor open", () => Game.ScreenStack.CurrentScreen is Editor editor && editor.ReadyForUse);
-
             makeMetadataChange();
 
-            AddAssert("save", () => Game.ChildrenOfType<Editor>().Single().Save());
+            AddAssert("save", () => getEditor().Save());
 
             AddStep("delete beatmap", () => Game.BeatmapManager.Delete(beatmapSet));
 
-            AddStep("exit", () => Game.ChildrenOfType<Editor>().Single().Exit());
+            AddStep("exit", () => getEditor().Exit());
 
             AddUntilStep("wait for song select", () => Game.ScreenStack.CurrentScreen is PlaySongSelect songSelect
                                                        && songSelect.Beatmap.Value is DummyWorkingBeatmap);
@@ -61,24 +113,14 @@ namespace osu.Game.Tests.Visual.Navigation
         [Test]
         public void TestChangeMetadataExitWhileTextboxFocusedPromptsSave()
         {
-            BeatmapSetInfo beatmapSet = null!;
-
-            AddStep("import test beatmap", () => Game.BeatmapManager.Import(TestResources.GetTestBeatmapForImport()).WaitSafely());
-            AddStep("retrieve beatmap", () => beatmapSet = Game.BeatmapManager.QueryBeatmapSet(set => !set.Protected).AsNonNull().Value.Detach());
-
-            AddStep("present beatmap", () => Game.PresentBeatmap(beatmapSet));
-            AddUntilStep("wait for song select",
-                () => Game.Beatmap.Value.BeatmapSetInfo.Equals(beatmapSet)
-                      && Game.ScreenStack.CurrentScreen is PlaySongSelect songSelect
-                      && songSelect.IsLoaded);
             AddStep("switch ruleset", () => Game.Ruleset.Value = new ManiaRuleset().RulesetInfo);
 
-            AddStep("open editor", () => ((PlaySongSelect)Game.ScreenStack.CurrentScreen).Edit(beatmapSet.Beatmaps.First(beatmap => beatmap.Ruleset.OnlineID == 0)));
+            prepareBeatmap();
-            AddUntilStep("wait for editor open", () => Game.ScreenStack.CurrentScreen is Editor editor && editor.ReadyForUse);
+            openEditor();
 
             makeMetadataChange(commit: false);
 
-            AddStep("exit", () => Game.ChildrenOfType<Editor>().Single().Exit());
+            AddStep("exit", () => getEditor().Exit());
 
             AddUntilStep("save dialog displayed", () => Game.ChildrenOfType<DialogOverlay>().SingleOrDefault()?.CurrentDialog is PromptForSaveDialog);
         }
@@ -121,16 +163,8 @@ namespace osu.Game.Tests.Visual.Navigation
         [Test]
         public void TestEditorGameplayTestAlwaysUsesOriginalRuleset()
         {
-            BeatmapSetInfo beatmapSet = null!;
+            prepareBeatmap();
 
-            AddStep("import test beatmap", () => Game.BeatmapManager.Import(TestResources.GetTestBeatmapForImport()).WaitSafely());
-            AddStep("retrieve beatmap", () => beatmapSet = Game.BeatmapManager.QueryBeatmapSet(set => !set.Protected).AsNonNull().Value.Detach());
-
-            AddStep("present beatmap", () => Game.PresentBeatmap(beatmapSet));
-            AddUntilStep("wait for song select",
-                () => Game.Beatmap.Value.BeatmapSetInfo.Equals(beatmapSet)
-                      && Game.ScreenStack.CurrentScreen is PlaySongSelect songSelect
-                      && songSelect.IsLoaded);
             AddStep("switch ruleset", () => Game.Ruleset.Value = new ManiaRuleset().RulesetInfo);
 
             AddStep("open editor", () => ((PlaySongSelect)Game.ScreenStack.CurrentScreen).Edit(beatmapSet.Beatmaps.First(beatmap => beatmap.Ruleset.OnlineID == 0)));
@@ -183,19 +217,8 @@ namespace osu.Game.Tests.Visual.Navigation
         [Test]
         public void TestExitEditorWithoutSelection()
         {
-            BeatmapSetInfo beatmapSet = null!;
+            prepareBeatmap();
-
+            openEditor();
-            AddStep("import test beatmap", () => Game.BeatmapManager.Import(TestResources.GetTestBeatmapForImport()).WaitSafely());
-            AddStep("retrieve beatmap", () => beatmapSet = Game.BeatmapManager.QueryBeatmapSet(set => !set.Protected).AsNonNull().Value.Detach());
-
-            AddStep("present beatmap", () => Game.PresentBeatmap(beatmapSet));
-            AddUntilStep("wait for song select",
-                () => Game.Beatmap.Value.BeatmapSetInfo.Equals(beatmapSet)
-                      && Game.ScreenStack.CurrentScreen is PlaySongSelect songSelect
-                      && songSelect.IsLoaded);
-
-            AddStep("open editor", () => ((PlaySongSelect)Game.ScreenStack.CurrentScreen).Edit(beatmapSet.Beatmaps.First(beatmap => beatmap.Ruleset.OnlineID == 0)));
-            AddUntilStep("wait for editor open", () => Game.ScreenStack.CurrentScreen is Editor editor && editor.ReadyForUse);
 
             AddStep("escape once", () => InputManager.Key(Key.Escape));
 
@@ -205,19 +228,8 @@ namespace osu.Game.Tests.Visual.Navigation
         [Test]
         public void TestExitEditorWithSelection()
         {
-            BeatmapSetInfo beatmapSet = null!;
+            prepareBeatmap();
-
+            openEditor();
-            AddStep("import test beatmap", () => Game.BeatmapManager.Import(TestResources.GetTestBeatmapForImport()).WaitSafely());
-            AddStep("retrieve beatmap", () => beatmapSet = Game.BeatmapManager.QueryBeatmapSet(set => !set.Protected).AsNonNull().Value.Detach());
-
-            AddStep("present beatmap", () => Game.PresentBeatmap(beatmapSet));
-            AddUntilStep("wait for song select",
-                () => Game.Beatmap.Value.BeatmapSetInfo.Equals(beatmapSet)
-                      && Game.ScreenStack.CurrentScreen is PlaySongSelect songSelect
-                      && songSelect.IsLoaded);
-
-            AddStep("open editor", () => ((PlaySongSelect)Game.ScreenStack.CurrentScreen).Edit(beatmapSet.Beatmaps.First(beatmap => beatmap.Ruleset.OnlineID == 0)));
-            AddUntilStep("wait for editor open", () => Game.ScreenStack.CurrentScreen is Editor editor && editor.ReadyForUse);
 
             AddStep("make selection", () =>
             {
@@ -239,19 +251,8 @@ namespace osu.Game.Tests.Visual.Navigation
         [Test]
         public void TestLastTimestampRememberedOnExit()
         {
-            BeatmapSetInfo beatmapSet = null!;
+            prepareBeatmap();
-
+            openEditor();
-            AddStep("import test beatmap", () => Game.BeatmapManager.Import(TestResources.GetTestBeatmapForImport()).WaitSafely());
-            AddStep("retrieve beatmap", () => beatmapSet = Game.BeatmapManager.QueryBeatmapSet(set => !set.Protected).AsNonNull().Value.Detach());
-
-            AddStep("present beatmap", () => Game.PresentBeatmap(beatmapSet));
-            AddUntilStep("wait for song select",
-                () => Game.Beatmap.Value.BeatmapSetInfo.Equals(beatmapSet)
-                      && Game.ScreenStack.CurrentScreen is PlaySongSelect songSelect
-                      && songSelect.IsLoaded);
-
-            AddStep("open editor", () => ((PlaySongSelect)Game.ScreenStack.CurrentScreen).Edit(beatmapSet.Beatmaps.First(beatmap => beatmap.Ruleset.OnlineID == 0)));
-            AddUntilStep("wait for editor open", () => Game.ScreenStack.CurrentScreen is Editor editor && editor.ReadyForUse);
 
             AddStep("seek to arbitrary time", () => getEditor().ChildrenOfType<EditorClock>().First().Seek(1234));
             AddUntilStep("time is correct", () => getEditor().ChildrenOfType<EditorClock>().First().CurrentTime, () => Is.EqualTo(1234));
@@ -259,32 +260,21 @@ namespace osu.Game.Tests.Visual.Navigation
             AddStep("exit editor", () => InputManager.Key(Key.Escape));
             AddUntilStep("wait for editor exit", () => Game.ScreenStack.CurrentScreen is not Editor);
 
-            AddStep("open editor", () => ((PlaySongSelect)Game.ScreenStack.CurrentScreen).Edit());
+            openEditor();
 
-            AddUntilStep("wait for editor open", () => Game.ScreenStack.CurrentScreen is Editor editor && editor.ReadyForUse);
             AddUntilStep("time is correct", () => getEditor().ChildrenOfType<EditorClock>().First().CurrentTime, () => Is.EqualTo(1234));
         }
 
         [Test]
         public void TestAttemptGlobalMusicOperationFromEditor()
         {
-            BeatmapSetInfo beatmapSet = null!;
+            prepareBeatmap();
-
-            AddStep("import test beatmap", () => Game.BeatmapManager.Import(TestResources.GetTestBeatmapForImport()).WaitSafely());
-            AddStep("retrieve beatmap", () => beatmapSet = Game.BeatmapManager.QueryBeatmapSet(set => !set.Protected).AsNonNull().Value.Detach());
-
-            AddStep("present beatmap", () => Game.PresentBeatmap(beatmapSet));
-            AddUntilStep("wait for song select",
-                () => Game.Beatmap.Value.BeatmapSetInfo.Equals(beatmapSet)
-                      && Game.ScreenStack.CurrentScreen is PlaySongSelect songSelect
-                      && songSelect.IsLoaded);
 
             AddUntilStep("wait for music playing", () => Game.MusicController.IsPlaying);
             AddStep("user request stop", () => Game.MusicController.Stop(requestedByUser: true));
             AddUntilStep("wait for music stopped", () => !Game.MusicController.IsPlaying);
 
-            AddStep("open editor", () => ((PlaySongSelect)Game.ScreenStack.CurrentScreen).Edit(beatmapSet.Beatmaps.First(beatmap => beatmap.Ruleset.OnlineID == 0)));
+            openEditor();
-            AddUntilStep("wait for editor open", () => Game.ScreenStack.CurrentScreen is Editor editor && editor.ReadyForUse);
 
             AddUntilStep("music still stopped", () => !Game.MusicController.IsPlaying);
             AddStep("user request play", () => Game.MusicController.Play(requestedByUser: true));
@@ -302,20 +292,10 @@ namespace osu.Game.Tests.Visual.Navigation
         [TestCase(SortMode.Difficulty)]
         public void TestSelectionRetainedOnExit(SortMode sortMode)
         {
-            BeatmapSetInfo beatmapSet = null!;
-
-            AddStep("import test beatmap", () => Game.BeatmapManager.Import(TestResources.GetTestBeatmapForImport()).WaitSafely());
-            AddStep("retrieve beatmap", () => beatmapSet = Game.BeatmapManager.QueryBeatmapSet(set => !set.Protected).AsNonNull().Value.Detach());
-
             AddStep($"set sort mode to {sortMode}", () => Game.LocalConfig.SetValue(OsuSetting.SongSelectSortingMode, sortMode));
-            AddStep("present beatmap", () => Game.PresentBeatmap(beatmapSet));
-            AddUntilStep("wait for song select",
-                () => Game.Beatmap.Value.BeatmapSetInfo.Equals(beatmapSet)
-                      && Game.ScreenStack.CurrentScreen is PlaySongSelect songSelect
-                      && songSelect.IsLoaded);
 
-            AddStep("open editor", () => ((PlaySongSelect)Game.ScreenStack.CurrentScreen).Edit(beatmapSet.Beatmaps.First(beatmap => beatmap.Ruleset.OnlineID == 0)));
+            prepareBeatmap();
-            AddUntilStep("wait for editor open", () => Game.ScreenStack.CurrentScreen is Editor editor && editor.ReadyForUse);
+            openEditor();
 
             AddStep("exit editor", () => InputManager.Key(Key.Escape));
             AddUntilStep("wait for editor exit", () => Game.ScreenStack.CurrentScreen is not Editor);
@@ -332,6 +312,7 @@ namespace osu.Game.Tests.Visual.Navigation
 
             AddStep("open editor", () => Game.ChildrenOfType<ButtonSystem>().Single().OnEditBeatmap?.Invoke());
             AddUntilStep("wait for editor", () => Game.ScreenStack.CurrentScreen is Editor editor && editor.IsLoaded);
+
             AddStep("click on file", () =>
             {
                 var item = getEditor().ChildrenOfType<Menu.DrawableMenuItem>().Single(i => i.Item.Text.Value.ToString() == "File");
@@ -354,6 +335,24 @@ namespace osu.Game.Tests.Visual.Navigation
             AddAssert("editor beatmap uses catch ruleset", () => getEditorBeatmap().BeatmapInfo.Ruleset.ShortName == "fruits");
         }
 
+        private void prepareBeatmap()
+        {
+            AddStep("import test beatmap", () => Game.BeatmapManager.Import(TestResources.GetTestBeatmapForImport()).WaitSafely());
+            AddStep("retrieve beatmap", () => beatmapSet = Game.BeatmapManager.QueryBeatmapSet(set => !set.Protected).AsNonNull().Value.Detach());
+
+            AddStep("present beatmap", () => Game.PresentBeatmap(beatmapSet));
+            AddUntilStep("wait for song select",
+                () => Game.Beatmap.Value.BeatmapSetInfo.Equals(beatmapSet)
+                      && Game.ScreenStack.CurrentScreen is PlaySongSelect songSelect
+                      && songSelect.IsLoaded);
+        }
+
+        private void openEditor()
+        {
+            AddStep("open editor", () => ((PlaySongSelect)Game.ScreenStack.CurrentScreen).Edit(beatmapSet.Beatmaps.First(beatmap => beatmap.Ruleset.OnlineID == 0)));
+            AddUntilStep("wait for editor open", () => Game.ScreenStack.CurrentScreen is Editor editor && editor.ReadyForUse);
+        }
+
         private EditorBeatmap getEditorBeatmap() => getEditor().ChildrenOfType<EditorBeatmap>().Single();
 
         private Editor getEditor() => (Editor)Game.ScreenStack.CurrentScreen;

osu.Game/Beatmaps/BeatmapManager.cs

@@ -415,6 +415,9 @@ namespace osu.Game.Beatmaps
         public Task<Live<BeatmapSetInfo>?> ImportAsUpdate(ProgressNotification notification, ImportTask importTask, BeatmapSetInfo original) =>
             beatmapImporter.ImportAsUpdate(notification, importTask, original);
 
+        public Task<ExternalEditOperation<BeatmapSetInfo>> BeginExternalEditing(BeatmapSetInfo model) =>
+            beatmapImporter.BeginExternalEditing(model);
+
         public Task Export(BeatmapSetInfo beatmap) => beatmapExporter.ExportAsync(beatmap.ToLive(Realm));
 
         public Task ExportLegacy(BeatmapSetInfo beatmap) => legacyBeatmapExporter.ExportAsync(beatmap.ToLive(Realm));

osu.Game/Database/ExternalEditOperation.cs

@@ -0,0 +1,65 @@
+// 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 System.Threading.Tasks;
+using osu.Game.Overlays.Notifications;
+
+namespace osu.Game.Database
+{
+    /// <summary>
+    /// Contains information related to an active external edit operation.
+    /// </summary>
+    public class ExternalEditOperation<TModel> where TModel : class, IHasGuidPrimaryKey
+    {
+        /// <summary>
+        /// The temporary path at which the model has been exported to for editing.
+        /// </summary>
+        public readonly string MountedPath;
+
+        /// <summary>
+        /// Whether the model is still mounted at <see cref="MountedPath"/>.
+        /// </summary>
+        public bool IsMounted { get; private set; }
+
+        private readonly IModelImporter<TModel> importer;
+        private readonly TModel original;
+
+        public ExternalEditOperation(IModelImporter<TModel> importer, TModel original, string path)
+        {
+            this.importer = importer;
+            this.original = original;
+
+            MountedPath = path;
+
+            IsMounted = true;
+        }
+
+        /// <summary>
+        /// Finish the external edit operation.
+        /// </summary>
+        /// <remarks>
+        /// This will trigger an asynchronous reimport of the model.
+        /// Subsequent calls will be a no-op.
+        /// </remarks>
+        /// <returns>A task which will eventuate in the newly imported model with changes applied.</returns>
+        public async Task<Live<TModel>?> Finish()
+        {
+            if (!Directory.Exists(MountedPath) || !IsMounted)
+                return null;
+
+            IsMounted = false;
+
+            Live<TModel>? imported = await importer.ImportAsUpdate(new ProgressNotification(), new ImportTask(MountedPath), original)
+                                                   .ConfigureAwait(false);
+
+            try
+            {
+                Directory.Delete(MountedPath, true);
+            }
+            catch { }
+
+            return imported;
+        }
+    }
+}

osu.Game/Database/IModelImporter.cs

@@ -34,6 +34,15 @@ namespace osu.Game.Database
         /// <returns>The imported model.</returns>
         Task<Live<TModel>?> ImportAsUpdate(ProgressNotification notification, ImportTask task, TModel original);
 
+        /// <summary>
+        /// Mount all files for a model to a temporary directory to allow for external editing.
+        /// </summary>
+        /// <remarks>
+        /// When editing is completed, call Finish() on the returned operation class to begin the import-and-update process.
+        /// </remarks>
+        /// <param name="model">The model to mount.</param>
+        public Task<ExternalEditOperation<TModel>> BeginExternalEditing(TModel model);
+
         /// <summary>
         /// A user displayable name for the model type associated with this manager.
         /// </summary>

osu.Game/Database/RealmArchiveModelImporter.cs

@@ -179,6 +179,30 @@ namespace osu.Game.Database
 
         public virtual Task<Live<TModel>?> ImportAsUpdate(ProgressNotification notification, ImportTask task, TModel original) => throw new NotImplementedException();
 
+        public async Task<ExternalEditOperation<TModel>> BeginExternalEditing(TModel model)
+        {
+            string mountedPath = Path.Join(Path.GetTempPath(), model.Hash);
+
+            if (Directory.Exists(mountedPath))
+                Directory.Delete(mountedPath, true);
+
+            Directory.CreateDirectory(mountedPath);
+
+            foreach (var realmFile in model.Files)
+            {
+                string sourcePath = Files.Storage.GetFullPath(realmFile.File.GetStoragePath());
+                string destinationPath = Path.Join(mountedPath, realmFile.Filename);
+
+                Directory.CreateDirectory(Path.GetDirectoryName(destinationPath)!);
+
+                using (var inStream = Files.Storage.GetStream(sourcePath))
+                using (var outStream = File.Create(destinationPath))
+                    await inStream.CopyToAsync(outStream).ConfigureAwait(false);
+            }
+
+            return new ExternalEditOperation<TModel>(this, model, mountedPath);
+        }
+
         /// <summary>
         /// Import one <typeparamref name="TModel"/> from the filesystem and delete the file on success.
         /// Note that this bypasses the UI flow and should only be used for special cases or testing.

osu.Game/Scoring/ScoreManager.cs

@@ -15,10 +15,10 @@ using osu.Game.Beatmaps;
 using osu.Game.Configuration;
 using osu.Game.Database;
 using osu.Game.IO.Archives;
+using osu.Game.Online.API;
 using osu.Game.Overlays.Notifications;
 using osu.Game.Rulesets;
 using osu.Game.Rulesets.Scoring;
-using osu.Game.Online.API;
 using osu.Game.Scoring.Legacy;
 
 namespace osu.Game.Scoring
@@ -214,6 +214,7 @@ namespace osu.Game.Scoring
         }
 
         public Task<Live<ScoreInfo>?> ImportAsUpdate(ProgressNotification notification, ImportTask task, ScoreInfo original) => scoreImporter.ImportAsUpdate(notification, task, original);
+        public Task<ExternalEditOperation<ScoreInfo>> BeginExternalEditing(ScoreInfo model) => scoreImporter.BeginExternalEditing(model);
 
         public Live<ScoreInfo>? Import(ScoreInfo item, ArchiveReader? archive = null, ImportParameters parameters = default, CancellationToken cancellationToken = default) =>
             scoreImporter.ImportModel(item, archive, parameters, cancellationToken);

osu.Game/Screens/Edit/Editor.cs

@@ -481,7 +481,7 @@ namespace osu.Game.Screens.Edit
         {
             if (HasUnsavedChanges)
             {
-                dialogOverlay.Push(new SaveRequiredPopupDialog("The beatmap will be saved in order to test it.", () => attemptMutationOperation(() =>
+                dialogOverlay.Push(new SaveRequiredPopupDialog(() => attemptMutationOperation(() =>
                 {
                     if (!Save()) return false;
 
@@ -1112,6 +1112,10 @@ namespace osu.Game.Screens.Edit
                 var export = createExportMenu();
                 saveRelatedMenuItems.AddRange(export.Items);
                 yield return export;
+
+                var externalEdit = new EditorMenuItem("Edit externally", MenuItemType.Standard, editExternally);
+                saveRelatedMenuItems.Add(externalEdit);
+                yield return externalEdit;
             }
 
             yield return new OsuMenuItemSpacer();
@@ -1129,11 +1133,35 @@ namespace osu.Game.Screens.Edit
             return new EditorMenuItem(CommonStrings.Export) { Items = exportItems };
         }
 
+        private void editExternally()
+        {
+            if (HasUnsavedChanges)
+            {
+                dialogOverlay.Push(new SaveRequiredPopupDialog(() => attemptMutationOperation(() =>
+                {
+                    if (!Save())
+                        return false;
+
+                    startEdit();
+                    return true;
+                })));
+            }
+            else
+            {
+                startEdit();
+            }
+
+            void startEdit()
+            {
+                this.Push(new ExternalEditScreen());
+            }
+        }
+
         private void exportBeatmap(bool legacy)
         {
             if (HasUnsavedChanges)
             {
-                dialogOverlay.Push(new SaveRequiredPopupDialog("The beatmap will be saved in order to export it.", () => attemptAsyncMutationOperation(() =>
+                dialogOverlay.Push(new SaveRequiredPopupDialog(() => attemptAsyncMutationOperation(() =>
                 {
                     if (!Save())
                         return Task.CompletedTask;
@@ -1211,17 +1239,14 @@ namespace osu.Game.Screens.Edit
         {
             if (isNewBeatmap)
             {
-                dialogOverlay.Push(new SaveRequiredPopupDialog("This beatmap will be saved in order to create another difficulty.", () =>
+                dialogOverlay.Push(new SaveRequiredPopupDialog(() => attemptMutationOperation(() =>
-                {
-                    attemptMutationOperation(() =>
                 {
                     if (!Save())
                         return false;
 
                     CreateNewDifficulty(rulesetInfo);
                     return true;
-                    });
+                })));
-                }));
 
                 return;
             }
@@ -1260,7 +1285,11 @@ namespace osu.Game.Screens.Edit
             return new EditorMenuItem(EditorStrings.ChangeDifficulty) { Items = difficultyItems };
         }
 
-        protected void SwitchToDifficulty(BeatmapInfo nextBeatmap) => loader?.ScheduleSwitchToExistingDifficulty(nextBeatmap, GetState(nextBeatmap.Ruleset));
+        public void SwitchToDifficulty(BeatmapInfo nextBeatmap)
+        {
+            switchingDifficulty = true;
+            loader?.ScheduleSwitchToExistingDifficulty(nextBeatmap, GetState(nextBeatmap.Ruleset));
+        }
 
         private void cancelExit()
         {

osu.Game/Screens/Edit/ExternalEditScreen.cs

@@ -0,0 +1,252 @@
+// 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 System.Threading.Tasks;
+using osu.Framework.Allocation;
+using osu.Framework.Extensions;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics.Shapes;
+using osu.Framework.Logging;
+using osu.Framework.Platform;
+using osu.Framework.Screens;
+using osu.Framework.Testing;
+using osu.Game.Beatmaps;
+using osu.Game.Database;
+using osu.Game.Graphics;
+using osu.Game.Graphics.Containers;
+using osu.Game.Graphics.Sprites;
+using osu.Game.Graphics.UserInterface;
+using osu.Game.Graphics.UserInterfaceV2;
+using osu.Game.Online.Multiplayer;
+using osu.Game.Overlays;
+using osu.Game.Screens.OnlinePlay.Match.Components;
+using osuTK;
+
+namespace osu.Game.Screens.Edit
+{
+    internal partial class ExternalEditScreen : OsuScreen
+    {
+        [Resolved]
+        private GameHost gameHost { get; set; } = null!;
+
+        [Resolved]
+        private OverlayColourProvider colourProvider { get; set; } = null!;
+
+        [Resolved]
+        private BeatmapManager beatmapManager { get; set; } = null!;
+
+        [Resolved]
+        private Editor editor { get; set; } = null!;
+
+        [Resolved]
+        private EditorBeatmap editorBeatmap { get; set; } = null!;
+
+        private Task? fileMountOperation;
+
+        public ExternalEditOperation<BeatmapSetInfo>? EditOperation;
+
+        private FillFlowContainer flow = null!;
+
+        [BackgroundDependencyLoader]
+        private void load()
+        {
+            InternalChild = new Container
+            {
+                Masking = true,
+                CornerRadius = 20,
+                AutoSizeAxes = Axes.Both,
+                AutoSizeDuration = 500,
+                AutoSizeEasing = Easing.OutQuint,
+                Anchor = Anchor.Centre,
+                Origin = Anchor.Centre,
+                Children = new Drawable[]
+                {
+                    new Box
+                    {
+                        Colour = colourProvider.Background5,
+                        RelativeSizeAxes = Axes.Both,
+                    },
+                    flow = new FillFlowContainer
+                    {
+                        Margin = new MarginPadding(20),
+                        AutoSizeAxes = Axes.Both,
+                        Direction = FillDirection.Vertical,
+                        Anchor = Anchor.TopCentre,
+                        Origin = Anchor.TopCentre,
+                        Spacing = new Vector2(15),
+                    }
+                }
+            };
+        }
+
+        protected override void LoadComplete()
+        {
+            base.LoadComplete();
+
+            fileMountOperation = begin();
+        }
+
+        public override bool OnExiting(ScreenExitEvent e)
+        {
+            // Don't allow exiting until the file mount operation has completed.
+            // This is mainly to simplify the flow (once the screen is pushed we are guaranteed an attempted mount).
+            if (fileMountOperation?.IsCompleted == false)
+                return true;
+
+            // If the operation completed successfully, ensure that we finish the operation before exiting.
+            // The finish() call will subsequently call Exit() when done.
+            if (EditOperation != null)
+            {
+                finish().FireAndForget();
+                return true;
+            }
+
+            return base.OnExiting(e);
+        }
+
+        private async Task begin()
+        {
+            showSpinner("Exporting for edit...");
+
+            await Task.Delay(500).ConfigureAwait(true);
+
+            try
+            {
+                EditOperation = await beatmapManager.BeginExternalEditing(editorBeatmap.BeatmapInfo.BeatmapSet!).ConfigureAwait(true);
+            }
+            catch (Exception ex)
+            {
+                Logger.Log($@"Failed to initiate external edit operation: {ex}", LoggingTarget.Database);
+                fileMountOperation = null;
+                showSpinner("Export failed!");
+                await Task.Delay(1000).ConfigureAwait(true);
+                this.Exit();
+            }
+
+            flow.Children = new Drawable[]
+            {
+                new OsuSpriteText
+                {
+                    Text = "Beatmap is mounted externally",
+                    Font = OsuFont.Default.With(size: 30),
+                    Anchor = Anchor.TopCentre,
+                    Origin = Anchor.TopCentre,
+                },
+                new OsuTextFlowContainer
+                {
+                    Padding = new MarginPadding(5),
+                    Anchor = Anchor.TopCentre,
+                    Origin = Anchor.TopCentre,
+                    Width = 350,
+                    AutoSizeAxes = Axes.Y,
+                    Text = "Any changes made to the exported folder will be imported to the game, including file additions, modifications and deletions.",
+                },
+                new PurpleRoundedButton
+                {
+                    Text = "Open folder",
+                    Width = 350,
+                    Anchor = Anchor.TopCentre,
+                    Origin = Anchor.TopCentre,
+                    Action = openDirectory,
+                    Enabled = { Value = false }
+                },
+                new DangerousRoundedButton
+                {
+                    Text = "Finish editing and import changes",
+                    Width = 350,
+                    Anchor = Anchor.TopCentre,
+                    Origin = Anchor.TopCentre,
+                    Action = () => finish().FireAndForget(),
+                    Enabled = { Value = false }
+                }
+            };
+
+            Scheduler.AddDelayed(() =>
+            {
+                foreach (var b in flow.ChildrenOfType<RoundedButton>())
+                    b.Enabled.Value = true;
+                openDirectory();
+            }, 1000);
+        }
+
+        private void openDirectory()
+        {
+            if (EditOperation == null)
+                return;
+
+            // Ensure the trailing separator is present in order to show the folder contents.
+            gameHost.OpenFileExternally(EditOperation.MountedPath.TrimDirectorySeparator() + Path.DirectorySeparatorChar);
+        }
+
+        private async Task finish()
+        {
+            string originalDifficulty = editor.Beatmap.Value.Beatmap.BeatmapInfo.DifficultyName;
+
+            showSpinner("Cleaning up...");
+
+            Live<BeatmapSetInfo>? beatmap = null;
+
+            try
+            {
+                beatmap = await EditOperation!.Finish().ConfigureAwait(true);
+            }
+            catch (Exception ex)
+            {
+                Logger.Log($@"Failed to finish external edit operation: {ex}", LoggingTarget.Database);
+                showSpinner("Import failed!");
+                await Task.Delay(1000).ConfigureAwait(true);
+            }
+
+            // Setting to null will allow exit to succeed.
+            EditOperation = null;
+
+            if (beatmap == null)
+                this.Exit();
+            else
+            {
+                // the `ImportAsUpdate()` flow will yield beatmap(sets) with online status of `None` if online lookup fails.
+                // coerce such models to `LocallyModified` state instead to unify behaviour with normal editing flow.
+                beatmap.PerformWrite(s =>
+                {
+                    if (s.Status == BeatmapOnlineStatus.None)
+                        s.Status = BeatmapOnlineStatus.LocallyModified;
+                    foreach (var difficulty in s.Beatmaps.Where(b => b.Status == BeatmapOnlineStatus.None))
+                        difficulty.Status = BeatmapOnlineStatus.LocallyModified;
+                });
+
+                var closestMatchingBeatmap =
+                    beatmap.Value.Beatmaps.FirstOrDefault(b => b.DifficultyName == originalDifficulty)
+                    ?? beatmap.Value.Beatmaps.First();
+
+                editor.SwitchToDifficulty(closestMatchingBeatmap);
+            }
+        }
+
+        private void showSpinner(string text)
+        {
+            foreach (var b in flow.ChildrenOfType<RoundedButton>())
+                b.Enabled.Value = false;
+
+            flow.Children = new Drawable[]
+            {
+                new OsuSpriteText
+                {
+                    Text = text,
+                    Font = OsuFont.Default.With(size: 30),
+                    Anchor = Anchor.TopCentre,
+                    Origin = Anchor.TopCentre,
+                },
+                new LoadingSpinner
+                {
+                    Anchor = Anchor.TopCentre,
+                    Origin = Anchor.TopCentre,
+                    State = { Value = Visibility.Visible }
+                },
+            };
+        }
+    }
+}

osu.Game/Screens/Edit/SaveRequiredPopupDialog.cs

@@ -9,9 +9,9 @@ namespace osu.Game.Screens.Edit
 {
     public partial class SaveRequiredPopupDialog : PopupDialog
     {
-        public SaveRequiredPopupDialog(string headerText, Action saveAndAction)
+        public SaveRequiredPopupDialog(Action saveAndAction)
         {
-            HeaderText = headerText;
+            HeaderText = "The beatmap will be saved to continue with this operation.";
 
             Icon = FontAwesome.Regular.Save;
 

osu.Game/Skinning/SkinManager.cs

@@ -312,6 +312,8 @@ namespace osu.Game.Skinning
         public Task<Live<SkinInfo>> ImportAsUpdate(ProgressNotification notification, ImportTask task, SkinInfo original) =>
             skinImporter.ImportAsUpdate(notification, task, original);
 
+        public Task<ExternalEditOperation<SkinInfo>> BeginExternalEditing(SkinInfo model) => skinImporter.BeginExternalEditing(model);
+
         public Task<Live<SkinInfo>> Import(ImportTask task, ImportParameters parameters = default, CancellationToken cancellationToken = default) =>
             skinImporter.Import(task, parameters, cancellationToken);