Rework decoders to be more flexible

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

@@ -24,7 +24,7 @@ public void TestDecodeBeatmapGeneral()
             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 @@ public void TestDecodeBeatmapEditor()
             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 @@ public void TestDecodeBeatmapMetadata()
             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 @@ public void TestDecodeBeatmapDifficulty()
             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 @@ public void TestDecodeBeatmapEvents()
             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 @@ public void TestDecodeBeatmapTimingPoints()
             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 @@ public void TestDecodeBeatmapColors()
             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 @@ public void TestDecodeBeatmapHitObjects()
             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 @@ public class LegacyStoryboardDecoderTest
         [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 @@ public void TestParity(string beatmap)
             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 @@ public void TestParity(string beatmap)
                     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 @@ public void TestReadMetadata()
 
                 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 @@ public class Beatmap<T> : IJsonSerializable
         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 @@ public class Beatmap : Beatmap<HitObject>
         /// 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 @@ protected override BeatmapSetInfo CreateModel(ArchiveReader reader)
 
             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 @@ private List<BeatmapInfo> createBeatmapDifficulties(ArchiveReader reader)
                     raw.CopyTo(ms);
                     ms.Position = 0;
 
-                    var decoder = Decoder.GetDecoder(sr);
-                    Beatmap beatmap = decoder.DecodeBeatmap(sr);
+                    var decoder = Decoder.GetDecoder<Beatmap>(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 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 @@ protected override Beatmap GetBeatmap()
                 try
                 {
                     using (var stream = new StreamReader(store.GetStream(getPathForFile(BeatmapInfo.Path))))
-                    {
-                        Decoder decoder = Decoder.GetDecoder(stream);
-                        return decoder.DecodeBeatmap(stream);
-                    }
+                        return Decoder.GetDecoder<Beatmap>(stream).Decode(stream);
                 }
                 catch
                 {
@@ -78,23 +76,23 @@ protected override Storyboard GetStoryboard()
                 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))))
-                                storyboard = decoder.GetStoryboardDecoder().DecodeStoryboard(beatmap, reader);
+                            using (var secondaryStream = new StreamReader(store.GetStream(getPathForFile(BeatmapSetInfo.StoryboardFile))))
+                                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

@@ -4,80 +4,77 @@
 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>
         /// Registers an instantiation function for a <see cref="Decoder"/>.
         /// </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>>());
 
-        /// <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;
+            typedDecoders[magic] = constructor;
         }
-
-        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 ParseBeatmap(StreamReader stream, Beatmap beatmap)
+        protected override void ParseStreamInto(StreamReader stream, Beatmap beatmap)
         {
             stream.BaseStream.Position = 0;
             stream.DiscardBufferedData();
@@ -26,10 +23,5 @@ protected override void ParseBeatmap(StreamReader stream, Beatmap beatmap)
             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();
-        }
     }
 }