Merge pull request #12754 from peppy/skin-instantiation-info

Add `SkinInfo.InstantiationInfo` to allow creating different skin types

osu.Game.Rulesets.Osu.Tests/TestSceneHitCircleArea.cs

@@ -32,7 +32,7 @@ namespace osu.Game.Rulesets.Osu.Tests
 
             hitCircle.ApplyDefaults(new ControlPointInfo(), new BeatmapDifficulty());
 
-            Child = new SkinProvidingContainer(new DefaultSkin())
+            Child = new SkinProvidingContainer(new DefaultSkin(null))
             {
                 RelativeSizeAxes = Axes.Both,
                 Child = drawableHitCircle = new DrawableHitCircle(hitCircle)

osu.Game/Beatmaps/WorkingBeatmap.cs

@@ -324,7 +324,7 @@ namespace osu.Game.Beatmaps
         public bool SkinLoaded => skin.IsResultAvailable;
         public ISkin Skin => skin.Value;
 
-        protected virtual ISkin GetSkin() => new DefaultSkin();
+        protected virtual ISkin GetSkin() => new DefaultSkin(null);
         private readonly RecyclableLazy<ISkin> skin;
 
         public abstract Stream GetStream(string storagePath);

osu.Game/Extensions/TypeExtensions.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;
+using System.Linq;
+
+namespace osu.Game.Extensions
+{
+    internal static class TypeExtensions
+    {
+        /// <summary>
+        /// Returns <paramref name="type"/>'s <see cref="Type.AssemblyQualifiedName"/>
+        /// with the assembly version, culture and public key token values removed.
+        /// </summary>
+        /// <remarks>
+        /// This method is usually used in extensibility scenarios (i.e. for custom rulesets or skins)
+        /// when a version-agnostic identifier associated with a C# class - potentially originating from
+        /// an external assembly - is needed.
+        /// Leaving only the type and assembly names in such a scenario allows to preserve compatibility
+        /// across assembly versions.
+        /// </remarks>
+        internal static string GetInvariantInstantiationInfo(this Type type)
+        {
+            string assemblyQualifiedName = type.AssemblyQualifiedName;
+            if (assemblyQualifiedName == null)
+                throw new ArgumentException($"{type}'s assembly-qualified name is null. Ensure that it is a concrete type and not a generic type parameter.", nameof(type));
+
+            return string.Join(',', assemblyQualifiedName.Split(',').Take(2));
+        }
+    }
+}

osu.Game/Migrations/20210511060743_AddSkinInstantiationInfo.Designer.cs

@@ -0,0 +1,508 @@
+// <auto-generated />
+using System;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Migrations;
+using Microsoft.EntityFrameworkCore.Storage.ValueConversion;
+using osu.Game.Database;
+
+namespace osu.Game.Migrations
+{
+    [DbContext(typeof(OsuDbContext))]
+    [Migration("20210511060743_AddSkinInstantiationInfo")]
+    partial class AddSkinInstantiationInfo
+    {
+        protected override void BuildTargetModel(ModelBuilder modelBuilder)
+        {
+#pragma warning disable 612, 618
+            modelBuilder
+                .HasAnnotation("ProductVersion", "2.2.6-servicing-10079");
+
+            modelBuilder.Entity("osu.Game.Beatmaps.BeatmapDifficulty", b =>
+                {
+                    b.Property<int>("ID")
+                        .ValueGeneratedOnAdd();
+
+                    b.Property<float>("ApproachRate");
+
+                    b.Property<float>("CircleSize");
+
+                    b.Property<float>("DrainRate");
+
+                    b.Property<float>("OverallDifficulty");
+
+                    b.Property<double>("SliderMultiplier");
+
+                    b.Property<double>("SliderTickRate");
+
+                    b.HasKey("ID");
+
+                    b.ToTable("BeatmapDifficulty");
+                });
+
+            modelBuilder.Entity("osu.Game.Beatmaps.BeatmapInfo", b =>
+                {
+                    b.Property<int>("ID")
+                        .ValueGeneratedOnAdd();
+
+                    b.Property<double>("AudioLeadIn");
+
+                    b.Property<double>("BPM");
+
+                    b.Property<int>("BaseDifficultyID");
+
+                    b.Property<int>("BeatDivisor");
+
+                    b.Property<int>("BeatmapSetInfoID");
+
+                    b.Property<bool>("Countdown");
+
+                    b.Property<double>("DistanceSpacing");
+
+                    b.Property<bool>("EpilepsyWarning");
+
+                    b.Property<int>("GridSize");
+
+                    b.Property<string>("Hash");
+
+                    b.Property<bool>("Hidden");
+
+                    b.Property<double>("Length");
+
+                    b.Property<bool>("LetterboxInBreaks");
+
+                    b.Property<string>("MD5Hash");
+
+                    b.Property<int?>("MetadataID");
+
+                    b.Property<int?>("OnlineBeatmapID");
+
+                    b.Property<string>("Path");
+
+                    b.Property<int>("RulesetID");
+
+                    b.Property<bool>("SpecialStyle");
+
+                    b.Property<float>("StackLeniency");
+
+                    b.Property<double>("StarDifficulty");
+
+                    b.Property<int>("Status");
+
+                    b.Property<string>("StoredBookmarks");
+
+                    b.Property<double>("TimelineZoom");
+
+                    b.Property<string>("Version");
+
+                    b.Property<bool>("WidescreenStoryboard");
+
+                    b.HasKey("ID");
+
+                    b.HasIndex("BaseDifficultyID");
+
+                    b.HasIndex("BeatmapSetInfoID");
+
+                    b.HasIndex("Hash");
+
+                    b.HasIndex("MD5Hash");
+
+                    b.HasIndex("MetadataID");
+
+                    b.HasIndex("OnlineBeatmapID")
+                        .IsUnique();
+
+                    b.HasIndex("RulesetID");
+
+                    b.ToTable("BeatmapInfo");
+                });
+
+            modelBuilder.Entity("osu.Game.Beatmaps.BeatmapMetadata", b =>
+                {
+                    b.Property<int>("ID")
+                        .ValueGeneratedOnAdd();
+
+                    b.Property<string>("Artist");
+
+                    b.Property<string>("ArtistUnicode");
+
+                    b.Property<string>("AudioFile");
+
+                    b.Property<string>("AuthorString")
+                        .HasColumnName("Author");
+
+                    b.Property<string>("BackgroundFile");
+
+                    b.Property<int>("PreviewTime");
+
+                    b.Property<string>("Source");
+
+                    b.Property<string>("Tags");
+
+                    b.Property<string>("Title");
+
+                    b.Property<string>("TitleUnicode");
+
+                    b.HasKey("ID");
+
+                    b.ToTable("BeatmapMetadata");
+                });
+
+            modelBuilder.Entity("osu.Game.Beatmaps.BeatmapSetFileInfo", b =>
+                {
+                    b.Property<int>("ID")
+                        .ValueGeneratedOnAdd();
+
+                    b.Property<int>("BeatmapSetInfoID");
+
+                    b.Property<int>("FileInfoID");
+
+                    b.Property<string>("Filename")
+                        .IsRequired();
+
+                    b.HasKey("ID");
+
+                    b.HasIndex("BeatmapSetInfoID");
+
+                    b.HasIndex("FileInfoID");
+
+                    b.ToTable("BeatmapSetFileInfo");
+                });
+
+            modelBuilder.Entity("osu.Game.Beatmaps.BeatmapSetInfo", b =>
+                {
+                    b.Property<int>("ID")
+                        .ValueGeneratedOnAdd();
+
+                    b.Property<DateTimeOffset>("DateAdded");
+
+                    b.Property<bool>("DeletePending");
+
+                    b.Property<string>("Hash");
+
+                    b.Property<int?>("MetadataID");
+
+                    b.Property<int?>("OnlineBeatmapSetID");
+
+                    b.Property<bool>("Protected");
+
+                    b.Property<int>("Status");
+
+                    b.HasKey("ID");
+
+                    b.HasIndex("DeletePending");
+
+                    b.HasIndex("Hash")
+                        .IsUnique();
+
+                    b.HasIndex("MetadataID");
+
+                    b.HasIndex("OnlineBeatmapSetID")
+                        .IsUnique();
+
+                    b.ToTable("BeatmapSetInfo");
+                });
+
+            modelBuilder.Entity("osu.Game.Configuration.DatabasedSetting", b =>
+                {
+                    b.Property<int>("ID")
+                        .ValueGeneratedOnAdd();
+
+                    b.Property<string>("Key")
+                        .HasColumnName("Key");
+
+                    b.Property<int?>("RulesetID");
+
+                    b.Property<int?>("SkinInfoID");
+
+                    b.Property<string>("StringValue")
+                        .HasColumnName("Value");
+
+                    b.Property<int?>("Variant");
+
+                    b.HasKey("ID");
+
+                    b.HasIndex("SkinInfoID");
+
+                    b.HasIndex("RulesetID", "Variant");
+
+                    b.ToTable("Settings");
+                });
+
+            modelBuilder.Entity("osu.Game.IO.FileInfo", b =>
+                {
+                    b.Property<int>("ID")
+                        .ValueGeneratedOnAdd();
+
+                    b.Property<string>("Hash");
+
+                    b.Property<int>("ReferenceCount");
+
+                    b.HasKey("ID");
+
+                    b.HasIndex("Hash")
+                        .IsUnique();
+
+                    b.HasIndex("ReferenceCount");
+
+                    b.ToTable("FileInfo");
+                });
+
+            modelBuilder.Entity("osu.Game.Input.Bindings.DatabasedKeyBinding", b =>
+                {
+                    b.Property<int>("ID")
+                        .ValueGeneratedOnAdd();
+
+                    b.Property<int>("IntAction")
+                        .HasColumnName("Action");
+
+                    b.Property<string>("KeysString")
+                        .HasColumnName("Keys");
+
+                    b.Property<int?>("RulesetID");
+
+                    b.Property<int?>("Variant");
+
+                    b.HasKey("ID");
+
+                    b.HasIndex("IntAction");
+
+                    b.HasIndex("RulesetID", "Variant");
+
+                    b.ToTable("KeyBinding");
+                });
+
+            modelBuilder.Entity("osu.Game.Rulesets.RulesetInfo", b =>
+                {
+                    b.Property<int?>("ID")
+                        .ValueGeneratedOnAdd();
+
+                    b.Property<bool>("Available");
+
+                    b.Property<string>("InstantiationInfo");
+
+                    b.Property<string>("Name");
+
+                    b.Property<string>("ShortName");
+
+                    b.HasKey("ID");
+
+                    b.HasIndex("Available");
+
+                    b.HasIndex("ShortName")
+                        .IsUnique();
+
+                    b.ToTable("RulesetInfo");
+                });
+
+            modelBuilder.Entity("osu.Game.Scoring.ScoreFileInfo", b =>
+                {
+                    b.Property<int>("ID")
+                        .ValueGeneratedOnAdd();
+
+                    b.Property<int>("FileInfoID");
+
+                    b.Property<string>("Filename")
+                        .IsRequired();
+
+                    b.Property<int?>("ScoreInfoID");
+
+                    b.HasKey("ID");
+
+                    b.HasIndex("FileInfoID");
+
+                    b.HasIndex("ScoreInfoID");
+
+                    b.ToTable("ScoreFileInfo");
+                });
+
+            modelBuilder.Entity("osu.Game.Scoring.ScoreInfo", b =>
+                {
+                    b.Property<int>("ID")
+                        .ValueGeneratedOnAdd();
+
+                    b.Property<double>("Accuracy")
+                        .HasColumnType("DECIMAL(1,4)");
+
+                    b.Property<int>("BeatmapInfoID");
+
+                    b.Property<int>("Combo");
+
+                    b.Property<DateTimeOffset>("Date");
+
+                    b.Property<bool>("DeletePending");
+
+                    b.Property<string>("Hash");
+
+                    b.Property<int>("MaxCombo");
+
+                    b.Property<string>("ModsJson")
+                        .HasColumnName("Mods");
+
+                    b.Property<long?>("OnlineScoreID");
+
+                    b.Property<double?>("PP");
+
+                    b.Property<int>("Rank");
+
+                    b.Property<int>("RulesetID");
+
+                    b.Property<string>("StatisticsJson")
+                        .HasColumnName("Statistics");
+
+                    b.Property<long>("TotalScore");
+
+                    b.Property<int?>("UserID")
+                        .HasColumnName("UserID");
+
+                    b.Property<string>("UserString")
+                        .HasColumnName("User");
+
+                    b.HasKey("ID");
+
+                    b.HasIndex("BeatmapInfoID");
+
+                    b.HasIndex("OnlineScoreID")
+                        .IsUnique();
+
+                    b.HasIndex("RulesetID");
+
+                    b.ToTable("ScoreInfo");
+                });
+
+            modelBuilder.Entity("osu.Game.Skinning.SkinFileInfo", b =>
+                {
+                    b.Property<int>("ID")
+                        .ValueGeneratedOnAdd();
+
+                    b.Property<int>("FileInfoID");
+
+                    b.Property<string>("Filename")
+                        .IsRequired();
+
+                    b.Property<int>("SkinInfoID");
+
+                    b.HasKey("ID");
+
+                    b.HasIndex("FileInfoID");
+
+                    b.HasIndex("SkinInfoID");
+
+                    b.ToTable("SkinFileInfo");
+                });
+
+            modelBuilder.Entity("osu.Game.Skinning.SkinInfo", b =>
+                {
+                    b.Property<int>("ID")
+                        .ValueGeneratedOnAdd();
+
+                    b.Property<string>("Creator");
+
+                    b.Property<bool>("DeletePending");
+
+                    b.Property<string>("Hash");
+
+                    b.Property<string>("InstantiationInfo");
+
+                    b.Property<string>("Name");
+
+                    b.HasKey("ID");
+
+                    b.HasIndex("DeletePending");
+
+                    b.HasIndex("Hash")
+                        .IsUnique();
+
+                    b.ToTable("SkinInfo");
+                });
+
+            modelBuilder.Entity("osu.Game.Beatmaps.BeatmapInfo", b =>
+                {
+                    b.HasOne("osu.Game.Beatmaps.BeatmapDifficulty", "BaseDifficulty")
+                        .WithMany()
+                        .HasForeignKey("BaseDifficultyID")
+                        .OnDelete(DeleteBehavior.Cascade);
+
+                    b.HasOne("osu.Game.Beatmaps.BeatmapSetInfo", "BeatmapSet")
+                        .WithMany("Beatmaps")
+                        .HasForeignKey("BeatmapSetInfoID")
+                        .OnDelete(DeleteBehavior.Cascade);
+
+                    b.HasOne("osu.Game.Beatmaps.BeatmapMetadata", "Metadata")
+                        .WithMany("Beatmaps")
+                        .HasForeignKey("MetadataID");
+
+                    b.HasOne("osu.Game.Rulesets.RulesetInfo", "Ruleset")
+                        .WithMany()
+                        .HasForeignKey("RulesetID")
+                        .OnDelete(DeleteBehavior.Cascade);
+                });
+
+            modelBuilder.Entity("osu.Game.Beatmaps.BeatmapSetFileInfo", b =>
+                {
+                    b.HasOne("osu.Game.Beatmaps.BeatmapSetInfo")
+                        .WithMany("Files")
+                        .HasForeignKey("BeatmapSetInfoID")
+                        .OnDelete(DeleteBehavior.Cascade);
+
+                    b.HasOne("osu.Game.IO.FileInfo", "FileInfo")
+                        .WithMany()
+                        .HasForeignKey("FileInfoID")
+                        .OnDelete(DeleteBehavior.Cascade);
+                });
+
+            modelBuilder.Entity("osu.Game.Beatmaps.BeatmapSetInfo", b =>
+                {
+                    b.HasOne("osu.Game.Beatmaps.BeatmapMetadata", "Metadata")
+                        .WithMany("BeatmapSets")
+                        .HasForeignKey("MetadataID");
+                });
+
+            modelBuilder.Entity("osu.Game.Configuration.DatabasedSetting", b =>
+                {
+                    b.HasOne("osu.Game.Skinning.SkinInfo")
+                        .WithMany("Settings")
+                        .HasForeignKey("SkinInfoID");
+                });
+
+            modelBuilder.Entity("osu.Game.Scoring.ScoreFileInfo", b =>
+                {
+                    b.HasOne("osu.Game.IO.FileInfo", "FileInfo")
+                        .WithMany()
+                        .HasForeignKey("FileInfoID")
+                        .OnDelete(DeleteBehavior.Cascade);
+
+                    b.HasOne("osu.Game.Scoring.ScoreInfo")
+                        .WithMany("Files")
+                        .HasForeignKey("ScoreInfoID");
+                });
+
+            modelBuilder.Entity("osu.Game.Scoring.ScoreInfo", b =>
+                {
+                    b.HasOne("osu.Game.Beatmaps.BeatmapInfo", "Beatmap")
+                        .WithMany("Scores")
+                        .HasForeignKey("BeatmapInfoID")
+                        .OnDelete(DeleteBehavior.Cascade);
+
+                    b.HasOne("osu.Game.Rulesets.RulesetInfo", "Ruleset")
+                        .WithMany()
+                        .HasForeignKey("RulesetID")
+                        .OnDelete(DeleteBehavior.Cascade);
+                });
+
+            modelBuilder.Entity("osu.Game.Skinning.SkinFileInfo", b =>
+                {
+                    b.HasOne("osu.Game.IO.FileInfo", "FileInfo")
+                        .WithMany()
+                        .HasForeignKey("FileInfoID")
+                        .OnDelete(DeleteBehavior.Cascade);
+
+                    b.HasOne("osu.Game.Skinning.SkinInfo")
+                        .WithMany("Files")
+                        .HasForeignKey("SkinInfoID")
+                        .OnDelete(DeleteBehavior.Cascade);
+                });
+#pragma warning restore 612, 618
+        }
+    }
+}

osu.Game/Migrations/20210511060743_AddSkinInstantiationInfo.cs

@@ -0,0 +1,22 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+namespace osu.Game.Migrations
+{
+    public partial class AddSkinInstantiationInfo : Migration
+    {
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.AddColumn<string>(
+                name: "InstantiationInfo",
+                table: "SkinInfo",
+                nullable: true);
+        }
+
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropColumn(
+                name: "InstantiationInfo",
+                table: "SkinInfo");
+        }
+    }
+}

osu.Game/Migrations/OsuDbContextModelSnapshot.cs

@@ -141,8 +141,6 @@ namespace osu.Game.Migrations
 
                     b.Property<string>("TitleUnicode");
 
-                    b.Property<string>("VideoFile");
-
                     b.HasKey("ID");
 
                     b.ToTable("BeatmapMetadata");
@@ -352,7 +350,7 @@ namespace osu.Game.Migrations
 
                     b.Property<long>("TotalScore");
 
-                    b.Property<long?>("UserID")
+                    b.Property<int?>("UserID")
                         .HasColumnName("UserID");
 
                     b.Property<string>("UserString")
@@ -402,6 +400,8 @@ namespace osu.Game.Migrations
 
                     b.Property<string>("Hash");
 
+                    b.Property<string>("InstantiationInfo");
+
                     b.Property<string>("Name");
 
                     b.HasKey("ID");

osu.Game/Rulesets/Ruleset.cs

@@ -26,6 +26,7 @@ using JetBrains.Annotations;
 using osu.Framework.Extensions;
 using osu.Framework.Extensions.EnumExtensions;
 using osu.Framework.Testing;
+using osu.Game.Extensions;
 using osu.Game.Rulesets.Filter;
 using osu.Game.Screens.Ranking.Statistics;
 
@@ -135,7 +136,7 @@ namespace osu.Game.Rulesets
                 Name = Description,
                 ShortName = ShortName,
                 ID = (this as ILegacyRuleset)?.LegacyID,
-                InstantiationInfo = GetType().AssemblyQualifiedName,
+                InstantiationInfo = GetType().GetInvariantInstantiationInfo(),
                 Available = true,
             };
         }

osu.Game/Rulesets/RulesetInfo.cs

@@ -3,7 +3,6 @@
 
 using System;
 using System.Diagnostics.CodeAnalysis;
-using System.Linq;
 using Newtonsoft.Json;
 using osu.Framework.Testing;
 
@@ -18,20 +17,7 @@ namespace osu.Game.Rulesets
 
         public string ShortName { get; set; }
 
-        private string instantiationInfo;
-
-        public string InstantiationInfo
-        {
-            get => instantiationInfo;
-            set => instantiationInfo = abbreviateInstantiationInfo(value);
-        }
-
-        private string abbreviateInstantiationInfo(string value)
-        {
-            // exclude version onwards, matching only on namespace and type.
-            // this is mainly to allow for new versions of already loaded rulesets to "upgrade" from old.
-            return string.Join(',', value.Split(',').Take(2));
-        }
+        public string InstantiationInfo { get; set; }
 
         [JsonIgnore]
         public bool Available { get; set; }

osu.Game/Skinning/DefaultLegacySkin.cs

@@ -1,7 +1,9 @@
 // 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.IO.Stores;
+using osu.Game.Extensions;
 using osu.Game.IO;
 using osuTK.Graphics;
 
@@ -10,7 +12,13 @@ namespace osu.Game.Skinning
     public class DefaultLegacySkin : LegacySkin
     {
         public DefaultLegacySkin(IResourceStore<byte[]> storage, IStorageResourceProvider resources)
-            : base(Info, storage, resources, string.Empty)
+            : this(Info, storage, resources)
+        {
+        }
+
+        [UsedImplicitly(ImplicitUseKindFlags.InstantiatedWithFixedConstructorSignature)]
+        public DefaultLegacySkin(SkinInfo skin, IResourceStore<byte[]> storage, IStorageResourceProvider resources)
+            : base(skin, storage, resources, string.Empty)
         {
             Configuration.CustomColours["SliderBall"] = new Color4(2, 170, 255, 255);
             Configuration.AddComboColours(
@@ -27,7 +35,8 @@ namespace osu.Game.Skinning
         {
             ID = SkinInfo.CLASSIC_SKIN, // this is temporary until database storage is decided upon.
             Name = "osu!classic",
-            Creator = "team osu!"
+            Creator = "team osu!",
+            InstantiationInfo = typeof(DefaultLegacySkin).GetInvariantInstantiationInfo()
         };
     }
 }

osu.Game/Skinning/DefaultSkin.cs

@@ -2,20 +2,28 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using System.Collections.Generic;
+using JetBrains.Annotations;
 using osu.Framework.Audio.Sample;
 using osu.Framework.Bindables;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.OpenGL.Textures;
 using osu.Framework.Graphics.Textures;
 using osu.Game.Audio;
+using osu.Game.IO;
 using osuTK.Graphics;
 
 namespace osu.Game.Skinning
 {
     public class DefaultSkin : Skin
     {
-        public DefaultSkin()
-            : base(SkinInfo.Default)
+        public DefaultSkin(IStorageResourceProvider resources)
+            : this(SkinInfo.Default, resources)
+        {
+        }
+
+        [UsedImplicitly(ImplicitUseKindFlags.InstantiatedWithFixedConstructorSignature)]
+        public DefaultSkin(SkinInfo skin, IStorageResourceProvider resources)
+            : base(skin)
         {
             Configuration = new DefaultSkinConfiguration();
         }

osu.Game/Skinning/LegacySkin.cs

@@ -52,6 +52,7 @@ namespace osu.Game.Skinning
 
         private readonly Dictionary<int, LegacyManiaSkinConfiguration> maniaConfigurations = new Dictionary<int, LegacyManiaSkinConfiguration>();
 
+        [UsedImplicitly(ImplicitUseKindFlags.InstantiatedWithFixedConstructorSignature)]
         public LegacySkin(SkinInfo skin, IStorageResourceProvider resources)
             : this(skin, new LegacySkinResourceStore<SkinFileInfo>(skin, resources.Files), resources, "skin.ini")
         {

osu.Game/Skinning/SkinInfo.cs

@@ -3,8 +3,11 @@
 
 using System;
 using System.Collections.Generic;
+using osu.Framework.IO.Stores;
 using osu.Game.Configuration;
 using osu.Game.Database;
+using osu.Game.Extensions;
+using osu.Game.IO;
 
 namespace osu.Game.Skinning
 {
@@ -22,7 +25,22 @@ namespace osu.Game.Skinning
 
         public string Creator { get; set; }
 
-        public List<SkinFileInfo> Files { get; set; }
+        public string InstantiationInfo { get; set; }
+
+        public virtual Skin CreateInstance(IResourceStore<byte[]> legacyDefaultResources, IStorageResourceProvider resources)
+        {
+            var type = string.IsNullOrEmpty(InstantiationInfo)
+                // handle the case of skins imported before InstantiationInfo was added.
+                ? typeof(LegacySkin)
+                : Type.GetType(InstantiationInfo);
+
+            if (type == typeof(DefaultLegacySkin))
+                return (Skin)Activator.CreateInstance(type, this, legacyDefaultResources, resources);
+
+            return (Skin)Activator.CreateInstance(type, this, resources);
+        }
+
+        public List<SkinFileInfo> Files { get; set; } = new List<SkinFileInfo>();
 
         public List<DatabasedSetting> Settings { get; set; }
 
@@ -32,7 +50,8 @@ namespace osu.Game.Skinning
         {
             ID = DEFAULT_SKIN,
             Name = "osu!lazer",
-            Creator = "team osu!"
+            Creator = "team osu!",
+            InstantiationInfo = typeof(DefaultSkin).GetInvariantInstantiationInfo()
         };
 
         public bool Equals(SkinInfo other) => other != null && ID == other.ID;

osu.Game/Skinning/SkinManager.cs

@@ -22,6 +22,7 @@ using osu.Framework.Testing;
 using osu.Framework.Utils;
 using osu.Game.Audio;
 using osu.Game.Database;
+using osu.Game.Extensions;
 using osu.Game.IO;
 using osu.Game.IO.Archives;
 
@@ -36,7 +37,7 @@ namespace osu.Game.Skinning
 
         private readonly IResourceStore<byte[]> legacyDefaultResources;
 
-        public readonly Bindable<Skin> CurrentSkin = new Bindable<Skin>(new DefaultSkin());
+        public readonly Bindable<Skin> CurrentSkin = new Bindable<Skin>(new DefaultSkin(null));
         public readonly Bindable<SkinInfo> CurrentSkinInfo = new Bindable<SkinInfo>(SkinInfo.Default) { Default = SkinInfo.Default };
 
         public override IEnumerable<string> HandledExtensions => new[] { ".osk" };
@@ -105,7 +106,7 @@ namespace osu.Game.Skinning
         {
             // we need to populate early to create a hash based off skin.ini contents
             if (item.Name?.Contains(".osk", StringComparison.OrdinalIgnoreCase) == true)
-                populateMetadata(item);
+                populateMetadata(item, GetSkin(item));
 
             if (item.Creator != null && item.Creator != unknown_creator_string)
             {
@@ -122,18 +123,20 @@ namespace osu.Game.Skinning
         {
             await base.Populate(model, archive, cancellationToken).ConfigureAwait(false);
 
+            var instance = GetSkin(model);
+
+            model.InstantiationInfo ??= instance.GetType().GetInvariantInstantiationInfo();
+
             if (model.Name?.Contains(".osk", StringComparison.OrdinalIgnoreCase) == true)
-                populateMetadata(model);
+                populateMetadata(model, instance);
         }
 
-        private void populateMetadata(SkinInfo item)
+        private void populateMetadata(SkinInfo item, Skin instance)
         {
-            Skin reference = GetSkin(item);
-
-            if (!string.IsNullOrEmpty(reference.Configuration.SkinInfo.Name))
+            if (!string.IsNullOrEmpty(instance.Configuration.SkinInfo.Name))
             {
-                item.Name = reference.Configuration.SkinInfo.Name;
-                item.Creator = reference.Configuration.SkinInfo.Creator;
+                item.Name = instance.Configuration.SkinInfo.Name;
+                item.Creator = instance.Configuration.SkinInfo.Creator;
             }
             else
             {
@@ -147,16 +150,7 @@ namespace osu.Game.Skinning
         /// </summary>
         /// <param name="skinInfo">The skin to lookup.</param>
         /// <returns>A <see cref="Skin"/> instance correlating to the provided <see cref="SkinInfo"/>.</returns>
-        public Skin GetSkin(SkinInfo skinInfo)
-        {
-            if (skinInfo == SkinInfo.Default)
-                return new DefaultSkin();
-
-            if (skinInfo == DefaultLegacySkin.Info)
-                return new DefaultLegacySkin(legacyDefaultResources, this);
-
-            return new LegacySkin(skinInfo, this);
-        }
+        public Skin GetSkin(SkinInfo skinInfo) => skinInfo.CreateInstance(legacyDefaultResources, this);
 
         /// <summary>
         /// Perform a lookup query on available <see cref="SkinInfo"/>s.