Initial push for better decoders

osu.Game.Tests/Beatmaps/Formats/LegacyBeatmapDecoderTest.cs

@@ -24,7 +24,7 @@ namespace osu.Game.Tests.Beatmaps.Formats
             using (var resStream = Resource.OpenResource("Soleily - Renatus (Gamu) [Insane].osu"))
             using (var stream = new StreamReader(resStream))
             {
-                var beatmap = decoder.DecodeBeatmap(stream);
+                var beatmap = decoder.Decode(stream);
                 var beatmapInfo = beatmap.BeatmapInfo;
                 var metadata = beatmap.Metadata;
 
@@ -47,7 +47,7 @@ namespace osu.Game.Tests.Beatmaps.Formats
             using (var resStream = Resource.OpenResource("Soleily - Renatus (Gamu) [Insane].osu"))
             using (var stream = new StreamReader(resStream))
             {
-                var beatmapInfo = decoder.DecodeBeatmap(stream).BeatmapInfo;
+                var beatmapInfo = decoder.Decode(stream).BeatmapInfo;
 
                 int[] expectedBookmarks =
                 {
@@ -72,7 +72,7 @@ namespace osu.Game.Tests.Beatmaps.Formats
             using (var resStream = Resource.OpenResource("Soleily - Renatus (Gamu) [Insane].osu"))
             using (var stream = new StreamReader(resStream))
             {
-                var beatmap = decoder.DecodeBeatmap(stream);
+                var beatmap = decoder.Decode(stream);
                 var beatmapInfo = beatmap.BeatmapInfo;
                 var metadata = beatmap.Metadata;
 
@@ -96,7 +96,7 @@ namespace osu.Game.Tests.Beatmaps.Formats
             using (var resStream = Resource.OpenResource("Soleily - Renatus (Gamu) [Insane].osu"))
             using (var stream = new StreamReader(resStream))
             {
-                var difficulty = decoder.DecodeBeatmap(stream).BeatmapInfo.BaseDifficulty;
+                var difficulty = decoder.Decode(stream).BeatmapInfo.BaseDifficulty;
 
                 Assert.AreEqual(6.5f, difficulty.DrainRate);
                 Assert.AreEqual(4, difficulty.CircleSize);
@@ -114,7 +114,7 @@ namespace osu.Game.Tests.Beatmaps.Formats
             using (var resStream = Resource.OpenResource("Soleily - Renatus (Gamu) [Insane].osu"))
             using (var stream = new StreamReader(resStream))
             {
-                var beatmap = decoder.DecodeBeatmap(stream);
+                var beatmap = decoder.Decode(stream);
                 var metadata = beatmap.Metadata;
                 var breakPoint = beatmap.Breaks[0];
 
@@ -132,7 +132,7 @@ namespace osu.Game.Tests.Beatmaps.Formats
             using (var resStream = Resource.OpenResource("Soleily - Renatus (Gamu) [Insane].osu"))
             using (var stream = new StreamReader(resStream))
             {
-                var beatmap = decoder.DecodeBeatmap(stream);
+                var beatmap = decoder.Decode(stream);
                 var controlPoints = beatmap.ControlPointInfo;
 
                 Assert.AreEqual(4, controlPoints.TimingPoints.Count);
@@ -167,7 +167,7 @@ namespace osu.Game.Tests.Beatmaps.Formats
             using (var resStream = Resource.OpenResource("Soleily - Renatus (Gamu) [Insane].osu"))
             using (var stream = new StreamReader(resStream))
             {
-                var comboColors = decoder.DecodeBeatmap(stream).ComboColors;
+                var comboColors = decoder.Decode(stream).ComboColors;
 
                 Color4[] expectedColors =
                 {
@@ -191,7 +191,7 @@ namespace osu.Game.Tests.Beatmaps.Formats
             using (var resStream = Resource.OpenResource("Soleily - Renatus (Gamu) [Insane].osu"))
             using (var stream = new StreamReader(resStream))
             {
-                var hitObjects = decoder.DecodeBeatmap(stream).HitObjects;
+                var hitObjects = decoder.Decode(stream).HitObjects;
 
                 var curveData = hitObjects[0] as IHasCurve;
                 var positionData = hitObjects[0] as IHasPosition;

osu.Game.Tests/Beatmaps/Formats/LegacyStoryboardDecoderTest.cs

@@ -18,11 +18,11 @@ namespace osu.Game.Tests.Beatmaps.Formats
         [Test]
         public void TestDecodeStoryboardEvents()
         {
-            var decoder = new LegacyBeatmapDecoder();
+            var decoder = new LegacyStoryboardDecoder();
             using (var resStream = Resource.OpenResource("Himeringo - Yotsuya-san ni Yoroshiku (RLC) [Winber1's Extreme].osu"))
             using (var stream = new StreamReader(resStream))
             {
-                var storyboard = decoder.GetStoryboardDecoder().DecodeStoryboard(stream);
+                var storyboard = decoder.Decode(stream);
 
                 Assert.IsTrue(storyboard.HasDrawable);
                 Assert.AreEqual(4, storyboard.Layers.Count());

osu.Game.Tests/Beatmaps/Formats/OsuJsonDecoderTest.cs

@@ -159,7 +159,7 @@ namespace osu.Game.Tests.Beatmaps.Formats
             using (var sr = new StreamReader(stream))
             {
 
-                var legacyDecoded = new LegacyBeatmapDecoder { ApplyOffsets = false }.DecodeBeatmap(sr);
+                var legacyDecoded = new LegacyBeatmapDecoder { ApplyOffsets = false }.Decode(sr);
                 using (var ms = new MemoryStream())
                 using (var sw = new StreamWriter(ms))
                 using (var sr2 = new StreamReader(ms))
@@ -168,7 +168,7 @@ namespace osu.Game.Tests.Beatmaps.Formats
                     sw.Flush();
 
                     ms.Position = 0;
-                    return (legacyDecoded, new JsonBeatmapDecoder().DecodeBeatmap(sr2));
+                    return (legacyDecoded, new JsonBeatmapDecoder().Decode(sr2));
                 }
             }
         }

osu.Game.Tests/Beatmaps/IO/OszArchiveReaderTest.cs

@@ -50,7 +50,7 @@ namespace osu.Game.Tests.Beatmaps.IO
 
                 BeatmapMetadata meta;
                 using (var stream = new StreamReader(reader.GetStream("Soleily - Renatus (Deif) [Platter].osu")))
-                    meta = Decoder.GetDecoder(stream).DecodeBeatmap(stream).Metadata;
+                    meta = Decoder.GetDecoder<Beatmap>(stream).Decode(stream).Metadata;
 
                 Assert.AreEqual(241526, meta.OnlineBeatmapSetID);
                 Assert.AreEqual("Soleily", meta.Artist);

osu.Game/Beatmaps/Beatmap.cs

@@ -22,6 +22,7 @@ namespace osu.Game.Beatmaps
         public BeatmapInfo BeatmapInfo = new BeatmapInfo();
         public ControlPointInfo ControlPointInfo = new ControlPointInfo();
         public List<BreakPeriod> Breaks = new List<BreakPeriod>();
+
         public List<Color4> ComboColors = new List<Color4>
         {
             new Color4(17, 136, 170, 255),
@@ -85,9 +86,13 @@ namespace osu.Game.Beatmaps
         /// Constructs a new beatmap.
         /// </summary>
         /// <param name="original">The original beatmap to use the parameters of.</param>
-        public Beatmap(Beatmap original = null)
+        public Beatmap(Beatmap original)
             : base(original)
         {
         }
+
+        public Beatmap()
+        {
+        }
     }
 }

osu.Game/Beatmaps/BeatmapManager.cs

@@ -301,7 +301,7 @@ namespace osu.Game.Beatmaps
 
             BeatmapMetadata metadata;
             using (var stream = new StreamReader(reader.GetStream(mapName)))
-                metadata = Decoder.GetDecoder(stream).DecodeBeatmap(stream).Metadata;
+                metadata = Decoder.GetDecoder<Beatmap>(stream).Decode(stream).Metadata;
 
             return new BeatmapSetInfo
             {
@@ -328,8 +328,8 @@ namespace osu.Game.Beatmaps
                     raw.CopyTo(ms);
                     ms.Position = 0;
 
-                    var decoder = Decoder.GetDecoder(sr);
+                    var decoder = Decoder.GetDecoder<Beatmap>(sr);
-                    Beatmap beatmap = decoder.DecodeBeatmap(sr);
+                    Beatmap beatmap = decoder.Decode(sr);
 
                     beatmap.BeatmapInfo.Path = name;
                     beatmap.BeatmapInfo.Hash = ms.ComputeSHA2Hash();

osu.Game/Beatmaps/BeatmapManager_WorkingBeatmap.cs

@@ -7,6 +7,7 @@ using System.Linq;
 using osu.Framework.Audio.Track;
 using osu.Framework.Graphics.Textures;
 using osu.Framework.IO.Stores;
+using osu.Framework.Logging;
 using osu.Game.Beatmaps.Formats;
 using osu.Game.Graphics.Textures;
 using osu.Game.Storyboards;
@@ -30,10 +31,7 @@ namespace osu.Game.Beatmaps
                 try
                 {
                     using (var stream = new StreamReader(store.GetStream(getPathForFile(BeatmapInfo.Path))))
-                    {
+                        return Decoder.GetDecoder<Beatmap>(stream).Decode(stream);
-                        Decoder decoder = Decoder.GetDecoder(stream);
-                        return decoder.DecodeBeatmap(stream);
-                    }
                 }
                 catch
                 {
@@ -78,23 +76,23 @@ namespace osu.Game.Beatmaps
                 Storyboard storyboard;
                 try
                 {
-                    using (var beatmap = new StreamReader(store.GetStream(getPathForFile(BeatmapInfo.Path))))
+                    using (var stream = new StreamReader(store.GetStream(getPathForFile(BeatmapInfo.Path))))
                     {
-                        Decoder decoder = Decoder.GetDecoder(beatmap);
+                        var decoder = Decoder.GetDecoder<Storyboard>(stream);
 
                         // todo: support loading from both set-wide storyboard *and* beatmap specific.
-
                         if (BeatmapSetInfo?.StoryboardFile == null)
-                            storyboard = decoder.GetStoryboardDecoder().DecodeStoryboard(beatmap);
+                            storyboard = decoder.Decode(stream);
                         else
                         {
-                            using (var reader = new StreamReader(store.GetStream(getPathForFile(BeatmapSetInfo.StoryboardFile))))
+                            using (var secondaryStream = new StreamReader(store.GetStream(getPathForFile(BeatmapSetInfo.StoryboardFile))))
-                                storyboard = decoder.GetStoryboardDecoder().DecodeStoryboard(beatmap, reader);
+                                storyboard = decoder.Decode(stream, secondaryStream);
                         }
                     }
                 }
-                catch
+                catch (Exception e)
                 {
+                    Logger.Error(e, "Storyboard failed to load");
                     storyboard = new Storyboard();
                 }
 

osu.Game/Beatmaps/Formats/Decoder.cs

@@ -4,38 +4,64 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
-using osu.Game.Storyboards;
+using System.Linq;
 
 namespace osu.Game.Beatmaps.Formats
 {
+    public abstract class Decoder<TOutput> : Decoder
+        where TOutput : new()
+    {
+        protected virtual TOutput CreateTemplateObject() => new TOutput();
+
+        public TOutput Decode(StreamReader primaryStream, params StreamReader[] otherStreams)
+        {
+            var output = CreateTemplateObject();
+            foreach (StreamReader stream in new[] { primaryStream }.Concat(otherStreams))
+                ParseStreamInto(stream, output);
+            return output;
+        }
+
+        protected abstract void ParseStreamInto(StreamReader stream, TOutput beatmap);
+    }
+
     public abstract class Decoder
     {
-        private static readonly Dictionary<string, Func<string, Decoder>> decoders = new Dictionary<string, Func<string, Decoder>>();
+        private static readonly Dictionary<Type, Dictionary<string, Func<string, Decoder>>> decoders = new Dictionary<Type, Dictionary<string, Func<string, Decoder>>>();
 
         static Decoder()
         {
-            LegacyDecoder.Register();
+            LegacyBeatmapDecoder.Register();
             JsonBeatmapDecoder.Register();
+            LegacyStoryboardDecoder.Register();
         }
 
         /// <summary>
         /// Retrieves a <see cref="Decoder"/> to parse a <see cref="Beatmap"/>.
         /// </summary>
         /// <param name="stream">A stream pointing to the <see cref="Beatmap"/>.</param>
-        public static Decoder GetDecoder(StreamReader stream)
+        public static Decoder<T> GetDecoder<T>(StreamReader stream)
+            where T : new()
         {
             if (stream == null)
                 throw new ArgumentNullException(nameof(stream));
 
+            if (!decoders.TryGetValue(typeof(T), out var typedDecoders))
+                throw new IOException(@"Unknown decoder type");
+
             string line;
             do
-            { line = stream.ReadLine()?.Trim(); }
+            {
-            while (line != null && line.Length == 0);
+                line = stream.ReadLine()?.Trim();
+            } while (line != null && line.Length == 0);
 
-            if (line == null || !decoders.ContainsKey(line))
+            if (line == null)
                 throw new IOException(@"Unknown file format");
 
-            return decoders[line](line);
+            var decoder = typedDecoders.Select(d => line.StartsWith(d.Key) ? d.Value : null).FirstOrDefault();
+            if (decoder == null)
+                throw new IOException(@"Unknown file format");
+
+            return (Decoder<T>)decoder.Invoke(line);
         }
 
         /// <summary>
@@ -43,41 +69,12 @@ namespace osu.Game.Beatmaps.Formats
         /// </summary>
         /// <param name="magic">A string in the file which triggers this decoder to be used.</param>
         /// <param name="constructor">A function which constructs the <see cref="Decoder"/> given <paramref name="magic"/>.</param>
-        protected static void AddDecoder(string magic, Func<string, Decoder> constructor)
+        protected static void AddDecoder<T>(string magic, Func<string, Decoder> constructor)
         {
-            decoders[magic] = constructor;
+            if (!decoders.TryGetValue(typeof(T), out var typedDecoders))
+                decoders.Add(typeof(T), typedDecoders = new Dictionary<string, Func<string, Decoder>>());
+
+            typedDecoders[magic] = constructor;
         }
-
-        /// <summary>
-        /// Retrieves a <see cref="Decoder"/> to parse a <see cref="Storyboard"/>
-        /// </summary>
-        public abstract Decoder GetStoryboardDecoder();
-
-        public virtual Beatmap DecodeBeatmap(StreamReader stream)
-        {
-            var beatmap = new Beatmap
-            {
-                BeatmapInfo = new BeatmapInfo
-                {
-                    Metadata = new BeatmapMetadata(),
-                    BaseDifficulty = new BeatmapDifficulty(),
-                },
-            };
-
-            ParseBeatmap(stream, beatmap);
-            return beatmap;
-        }
-
-        protected abstract void ParseBeatmap(StreamReader stream, Beatmap beatmap);
-
-        public virtual Storyboard DecodeStoryboard(params StreamReader[] streams)
-        {
-            var storyboard = new Storyboard();
-            foreach (StreamReader stream in streams)
-                ParseStoryboard(stream, storyboard);
-            return storyboard;
-        }
-
-        protected abstract void ParseStoryboard(StreamReader stream, Storyboard storyboard);
     }
 }

osu.Game/Beatmaps/Formats/JsonBeatmapDecoder.cs

@@ -3,20 +3,17 @@
 
 using System.IO;
 using osu.Game.IO.Serialization;
-using osu.Game.Storyboards;
 
 namespace osu.Game.Beatmaps.Formats
 {
-    public class JsonBeatmapDecoder : Decoder
+    public class JsonBeatmapDecoder : Decoder<Beatmap>
     {
         public static void Register()
         {
-            AddDecoder("{", m => new JsonBeatmapDecoder());
+            AddDecoder<Beatmap>("{", m => new JsonBeatmapDecoder());
         }
 
-        public override Decoder GetStoryboardDecoder() => this;
+        protected override void ParseStreamInto(StreamReader stream, Beatmap beatmap)
-
-        protected override void ParseBeatmap(StreamReader stream, Beatmap beatmap)
         {
             stream.BaseStream.Position = 0;
             stream.DiscardBufferedData();
@@ -26,10 +23,5 @@ namespace osu.Game.Beatmaps.Formats
             foreach (var hitObject in beatmap.HitObjects)
                 hitObject.ApplyDefaults(beatmap.ControlPointInfo, beatmap.BeatmapInfo.BaseDifficulty);
         }
-
-        protected override void ParseStoryboard(StreamReader stream, Storyboard storyboard)
-        {
-            // throw new System.NotImplementedException();
-        }
     }
 }

osu.Game/Beatmaps/Formats/LegacyBeatmapDecoder.cs

@@ -4,6 +4,7 @@
 using System;
 using System.Globalization;
 using System.IO;
+using System.Linq;
 using OpenTK.Graphics;
 using osu.Game.Beatmaps.Timing;
 using osu.Game.Rulesets.Objects.Legacy;
@@ -12,8 +13,10 @@ using osu.Framework;
 
 namespace osu.Game.Beatmaps.Formats
 {
-    public class LegacyBeatmapDecoder : LegacyDecoder
+    public class LegacyBeatmapDecoder : LegacyDecoder<Beatmap>
     {
+        public const int LATEST_VERSION = 14;
+
         private Beatmap beatmap;
 
         private bool hasCustomColours;
@@ -22,6 +25,11 @@ namespace osu.Game.Beatmaps.Formats
         private LegacySampleBank defaultSampleBank;
         private int defaultSampleVolume = 100;
 
+        public static void Register()
+        {
+            AddDecoder<Beatmap>(@"osu file format v", m => new LegacyBeatmapDecoder(int.Parse(m.Split('v').Last())));
+        }
+
         /// <summary>
         /// lazer's audio timings in general doesn't match stable. this is the result of user testing, albeit limited.
         /// This only seems to be required on windows. We need to eventually figure out why, with a bit of luck.
@@ -35,29 +43,16 @@ namespace osu.Game.Beatmaps.Formats
 
         private readonly int offset = UniversalOffset;
 
-        public LegacyBeatmapDecoder()
+        public LegacyBeatmapDecoder(int version = LATEST_VERSION) : base(version)
         {
-        }
-
-        public LegacyBeatmapDecoder(string header)
-        {
-            BeatmapVersion = int.Parse(header.Substring(17));
-
             // BeatmapVersion 4 and lower had an incorrect offset (stable has this set as 24ms off)
-            offset += BeatmapVersion < 5 ? 24 : 0;
+            offset += FormatVersion < 5 ? 24 : 0;
         }
 
-        protected override void ParseBeatmap(StreamReader stream, Beatmap beatmap)
+        protected override void ParseStreamInto(StreamReader stream, Beatmap beatmap)
         {
-            if (stream == null)
-                throw new ArgumentNullException(nameof(stream));
-            if (beatmap == null)
-                throw new ArgumentNullException(nameof(beatmap));
-
             this.beatmap = beatmap;
-            this.beatmap.BeatmapInfo.BeatmapVersion = BeatmapVersion;
+            base.ParseStreamInto(stream, beatmap);
-
-            ParseContent(stream);
 
             // objects may be out of order *only* if a user has manually edited an .osu file.
             // unfortunately there are ranked maps in this state (example: https://osu.ppy.sh/s/594828).
@@ -67,14 +62,9 @@ namespace osu.Game.Beatmaps.Formats
                 hitObject.ApplyDefaults(this.beatmap.ControlPointInfo, this.beatmap.BeatmapInfo.BaseDifficulty);
         }
 
-        protected override bool ShouldSkipLine(string line)
+        protected override bool ShouldSkipLine(string line) => base.ShouldSkipLine(line) || line.StartsWith(" ") || line.StartsWith("_");
-        {
-            if (base.ShouldSkipLine(line) || line.StartsWith(" ") || line.StartsWith("_"))
-                return true;
-            return false;
-        }
 
-        protected override void ProcessSection(Section section, string line)
+        protected override void ParseLine(Beatmap beatmap, Section section, string line)
         {
             switch (section)
             {

osu.Game/Beatmaps/Formats/LegacyDecoder.cs

@@ -4,47 +4,20 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
-using osu.Game.Beatmaps.Legacy;
-using osu.Game.Storyboards;
 
 namespace osu.Game.Beatmaps.Formats
 {
-    public abstract class LegacyDecoder : Decoder
+    public abstract class LegacyDecoder<T> : Decoder<T>
+        where T : new()
     {
-        public static void Register()
+        protected readonly int FormatVersion;
+
+        protected LegacyDecoder(int version)
         {
-            AddDecoder(@"osu file format v14", m => new LegacyBeatmapDecoder(m));
+            FormatVersion = version;
-            AddDecoder(@"osu file format v13", m => new LegacyBeatmapDecoder(m));
-            AddDecoder(@"osu file format v12", m => new LegacyBeatmapDecoder(m));
-            AddDecoder(@"osu file format v11", m => new LegacyBeatmapDecoder(m));
-            AddDecoder(@"osu file format v10", m => new LegacyBeatmapDecoder(m));
-            AddDecoder(@"osu file format v9", m => new LegacyBeatmapDecoder(m));
-            AddDecoder(@"osu file format v8", m => new LegacyBeatmapDecoder(m));
-            AddDecoder(@"osu file format v7", m => new LegacyBeatmapDecoder(m));
-            AddDecoder(@"osu file format v6", m => new LegacyBeatmapDecoder(m));
-            AddDecoder(@"osu file format v5", m => new LegacyBeatmapDecoder(m));
-            AddDecoder(@"osu file format v4", m => new LegacyBeatmapDecoder(m));
-            AddDecoder(@"osu file format v3", m => new LegacyBeatmapDecoder(m));
-            // TODO: differences between versions
         }
 
-        protected int BeatmapVersion;
+        protected override void ParseStreamInto(StreamReader stream, T beatmap)
-
-        public override Decoder GetStoryboardDecoder() => new LegacyStoryboardDecoder(BeatmapVersion);
-
-        public override Beatmap DecodeBeatmap(StreamReader stream) => new LegacyBeatmap(base.DecodeBeatmap(stream));
-
-        protected override void ParseBeatmap(StreamReader stream, Beatmap beatmap)
-        {
-            throw new NotImplementedException();
-        }
-
-        protected override void ParseStoryboard(StreamReader stream, Storyboard storyboard)
-        {
-            throw new NotImplementedException();
-        }
-
-        protected void ParseContent(StreamReader stream)
         {
             Section section = Section.None;
 
@@ -54,13 +27,6 @@ namespace osu.Game.Beatmaps.Formats
                 if (ShouldSkipLine(line))
                     continue;
 
-                // It's already set in ParseBeatmap... why do it again?
-                //if (line.StartsWith(@"osu file format v"))
-                //{
-                //    Beatmap.BeatmapInfo.BeatmapVersion = int.Parse(line.Substring(17));
-                //    continue;
-                //}
-
                 if (line.StartsWith(@"[") && line.EndsWith(@"]"))
                 {
                     if (!Enum.TryParse(line.Substring(1, line.Length - 2), out section))
@@ -68,18 +34,13 @@ namespace osu.Game.Beatmaps.Formats
                     continue;
                 }
 
-                ProcessSection(section, line);
+                ParseLine(beatmap, section, line);
             }
         }
 
-        protected virtual bool ShouldSkipLine(string line)
+        protected virtual bool ShouldSkipLine(string line) => string.IsNullOrWhiteSpace(line) || line.StartsWith("//");
-        {
-            if (string.IsNullOrWhiteSpace(line) || line.StartsWith("//"))
-                return true;
-            return false;
-        }
 
-        protected abstract void ProcessSection(Section section, string line);
+        protected abstract void ParseLine(T output, Section section, string line);
 
         protected KeyValuePair<string, string> SplitKeyVal(string line, char separator)
         {

osu.Game/Beatmaps/Formats/LegacyStoryboardDecoder.cs

@@ -13,37 +13,34 @@ using osu.Game.Storyboards;
 
 namespace osu.Game.Beatmaps.Formats
 {
-    public class LegacyStoryboardDecoder : LegacyDecoder
+    public class LegacyStoryboardDecoder : LegacyDecoder<Storyboard>
     {
-        private Storyboard storyboard;
-
         private StoryboardSprite storyboardSprite;
         private CommandTimelineGroup timelineGroup;
 
+        private Storyboard storyboard;
+
         private readonly Dictionary<string, string> variables = new Dictionary<string, string>();
 
         public LegacyStoryboardDecoder()
+            : base(0)
         {
         }
 
-        public LegacyStoryboardDecoder(int beatmapVersion)
+        public static void Register()
         {
-            BeatmapVersion = beatmapVersion;
+            // note that this isn't completely correct
+            AddDecoder<Storyboard>(@"osu file format v", m => new LegacyStoryboardDecoder());
+            AddDecoder<Storyboard>(@"[Events]", m => new LegacyStoryboardDecoder());
         }
 
-        protected override void ParseStoryboard(StreamReader stream, Storyboard storyboard)
+        protected override void ParseStreamInto(StreamReader stream, Storyboard storyboard)
         {
-            if (stream == null)
-                throw new ArgumentNullException(nameof(stream));
-            if (storyboard == null)
-                throw new ArgumentNullException(nameof(storyboard));
-
             this.storyboard = storyboard;
-
+            base.ParseStreamInto(stream, storyboard);
-            ParseContent(stream);
         }
 
-        protected override void ProcessSection(Section section, string line)
+        protected override void ParseLine(Storyboard storyboard, Section section, string line)
         {
             switch (section)
             {
@@ -269,6 +266,7 @@ namespace osu.Game.Beatmaps.Formats
                 case LegacyOrigins.BottomRight:
                     return Anchor.BottomRight;
             }
+
             throw new InvalidDataException($@"Unknown origin: {value}");
         }
 

osu.Game/Rulesets/Objects/Legacy/ConvertHitObjectParser.cs

@@ -188,8 +188,8 @@ namespace osu.Game.Rulesets.Objects.Legacy
 
             string[] split = str.Split(':');
 
-            var bank = (LegacyDecoder.LegacySampleBank)Convert.ToInt32(split[0]);
+            var bank = (LegacyBeatmapDecoder.LegacySampleBank)Convert.ToInt32(split[0]);
-            var addbank = (LegacyDecoder.LegacySampleBank)Convert.ToInt32(split[1]);
+            var addbank = (LegacyBeatmapDecoder.LegacySampleBank)Convert.ToInt32(split[1]);
 
             // Let's not implement this for now, because this doesn't fit nicely into the bank structure
             //string sampleFile = split2.Length > 4 ? split2[4] : string.Empty;

osu.Game/Tests/Beatmaps/BeatmapConversionTest.cs

@@ -112,9 +112,9 @@ namespace osu.Game.Tests.Beatmaps
             using (var resStream = openResource($"{resource_namespace}.{name}.osu"))
             using (var stream = new StreamReader(resStream))
             {
-                var decoder = Decoder.GetDecoder(stream);
+                var decoder = Decoder.GetDecoder<Beatmap>(stream);
                 ((LegacyBeatmapDecoder)decoder).ApplyOffsets = false;
-                return decoder.DecodeBeatmap(stream);
+                return decoder.Decode(stream);
             }
         }
 

osu.Game/Tests/Visual/TestCasePlayer.cs

@@ -65,7 +65,7 @@ namespace osu.Game.Tests.Visual
 
             using (var stream = new MemoryStream(Encoding.UTF8.GetBytes(test_beatmap_data)))
             using (var reader = new StreamReader(stream))
-                beatmap = Game.Beatmaps.Formats.Decoder.GetDecoder(reader).DecodeBeatmap(reader);
+                beatmap = Game.Beatmaps.Formats.Decoder.GetDecoder<Beatmap>(reader).Decode(reader);
 
             return beatmap;
         }