diff --git a/osu.Game.Tests/Beatmaps/Formats/LegacyBeatmapDecoderTest.cs b/osu.Game.Tests/Beatmaps/Formats/LegacyBeatmapDecoderTest.cs index 6a77c6ca96..f6c0dbbecf 100644 --- a/osu.Game.Tests/Beatmaps/Formats/LegacyBeatmapDecoderTest.cs +++ b/osu.Game.Tests/Beatmaps/Formats/LegacyBeatmapDecoderTest.cs @@ -2,6 +2,7 @@ // See the LICENCE file in the repository root for full licence text. using System; +using System.IO; using NUnit.Framework; using osuTK; using osuTK.Graphics; @@ -490,5 +491,105 @@ namespace osu.Game.Tests.Beatmaps.Formats Assert.DoesNotThrow(() => decoder.Decode(badStream)); } } + + [Test] + public void TestFallbackDecoderForCorruptedHeader() + { + Decoder decoder = null; + Beatmap beatmap = null; + + using (var resStream = TestResources.OpenResource("corrupted-header.osu")) + using (var stream = new LineBufferedReader(resStream)) + { + Assert.DoesNotThrow(() => decoder = Decoder.GetDecoder(stream)); + Assert.IsInstanceOf(decoder); + Assert.DoesNotThrow(() => beatmap = decoder.Decode(stream)); + Assert.IsNotNull(beatmap); + Assert.AreEqual("Beatmap with corrupted header", beatmap.Metadata.Title); + Assert.AreEqual("Evil Hacker", beatmap.Metadata.AuthorString); + } + } + + [Test] + public void TestFallbackDecoderForMissingHeader() + { + Decoder decoder = null; + Beatmap beatmap = null; + + using (var resStream = TestResources.OpenResource("missing-header.osu")) + using (var stream = new LineBufferedReader(resStream)) + { + Assert.DoesNotThrow(() => decoder = Decoder.GetDecoder(stream)); + Assert.IsInstanceOf(decoder); + Assert.DoesNotThrow(() => beatmap = decoder.Decode(stream)); + Assert.IsNotNull(beatmap); + Assert.AreEqual("Beatmap with no header", beatmap.Metadata.Title); + Assert.AreEqual("Incredibly Evil Hacker", beatmap.Metadata.AuthorString); + } + } + + [Test] + public void TestDecodeFileWithEmptyLinesAtStart() + { + Decoder decoder = null; + Beatmap beatmap = null; + + using (var resStream = TestResources.OpenResource("empty-lines-at-start.osu")) + using (var stream = new LineBufferedReader(resStream)) + { + Assert.DoesNotThrow(() => decoder = Decoder.GetDecoder(stream)); + Assert.IsInstanceOf(decoder); + Assert.DoesNotThrow(() => beatmap = decoder.Decode(stream)); + Assert.IsNotNull(beatmap); + Assert.AreEqual("Empty lines at start", beatmap.Metadata.Title); + Assert.AreEqual("Edge Case Hunter", beatmap.Metadata.AuthorString); + } + } + + [Test] + public void TestDecodeFileWithEmptyLinesAndNoHeader() + { + Decoder decoder = null; + Beatmap beatmap = null; + + using (var resStream = TestResources.OpenResource("empty-line-instead-of-header.osu")) + using (var stream = new LineBufferedReader(resStream)) + { + Assert.DoesNotThrow(() => decoder = Decoder.GetDecoder(stream)); + Assert.IsInstanceOf(decoder); + Assert.DoesNotThrow(() => beatmap = decoder.Decode(stream)); + Assert.IsNotNull(beatmap); + Assert.AreEqual("The dog ate the file header", beatmap.Metadata.Title); + Assert.AreEqual("Why does this keep happening", beatmap.Metadata.AuthorString); + } + } + + [Test] + public void TestDecodeFileWithContentImmediatelyAfterHeader() + { + Decoder decoder = null; + Beatmap beatmap = null; + + using (var resStream = TestResources.OpenResource("no-empty-line-after-header.osu")) + using (var stream = new LineBufferedReader(resStream)) + { + Assert.DoesNotThrow(() => decoder = Decoder.GetDecoder(stream)); + Assert.IsInstanceOf(decoder); + Assert.DoesNotThrow(() => beatmap = decoder.Decode(stream)); + Assert.IsNotNull(beatmap); + Assert.AreEqual("No empty line delimiting header from contents", beatmap.Metadata.Title); + Assert.AreEqual("Edge Case Hunter", beatmap.Metadata.AuthorString); + } + } + + [Test] + public void TestDecodeEmptyFile() + { + using (var resStream = new MemoryStream()) + using (var stream = new LineBufferedReader(resStream)) + { + Assert.Throws(() => Decoder.GetDecoder(stream)); + } + } } } diff --git a/osu.Game.Tests/Beatmaps/IO/ImportBeatmapTest.cs b/osu.Game.Tests/Beatmaps/IO/ImportBeatmapTest.cs index ad0ed00989..0686073292 100644 --- a/osu.Game.Tests/Beatmaps/IO/ImportBeatmapTest.cs +++ b/osu.Game.Tests/Beatmaps/IO/ImportBeatmapTest.cs @@ -126,7 +126,7 @@ namespace osu.Game.Tests.Beatmaps.IO var breakTemp = TestResources.GetTestBeatmapForImport(); - MemoryStream brokenOsu = new MemoryStream(new byte[] { 1, 3, 3, 7 }); + MemoryStream brokenOsu = new MemoryStream(); MemoryStream brokenOsz = new MemoryStream(File.ReadAllBytes(breakTemp)); File.Delete(breakTemp); diff --git a/osu.Game.Tests/Resources/corrupted-header.osu b/osu.Game.Tests/Resources/corrupted-header.osu new file mode 100644 index 0000000000..92701a4a7d --- /dev/null +++ b/osu.Game.Tests/Resources/corrupted-header.osu @@ -0,0 +1,5 @@ +ow computerosu file format v14 + +[Metadata] +Title: Beatmap with corrupted header +Creator: Evil Hacker diff --git a/osu.Game.Tests/Resources/empty-line-instead-of-header.osu b/osu.Game.Tests/Resources/empty-line-instead-of-header.osu new file mode 100644 index 0000000000..91ecf8d84a --- /dev/null +++ b/osu.Game.Tests/Resources/empty-line-instead-of-header.osu @@ -0,0 +1,5 @@ + + +[Metadata] +Title: The dog ate the file header +Creator: Why does this keep happening \ No newline at end of file diff --git a/osu.Game.Tests/Resources/empty-lines-at-start.osu b/osu.Game.Tests/Resources/empty-lines-at-start.osu new file mode 100644 index 0000000000..cb3b1761a2 --- /dev/null +++ b/osu.Game.Tests/Resources/empty-lines-at-start.osu @@ -0,0 +1,8 @@ + + + +osu file format v14 + +[Metadata] +Title: Empty lines at start +Creator: Edge Case Hunter \ No newline at end of file diff --git a/osu.Game.Tests/Resources/missing-header.osu b/osu.Game.Tests/Resources/missing-header.osu new file mode 100644 index 0000000000..95fac0d79b --- /dev/null +++ b/osu.Game.Tests/Resources/missing-header.osu @@ -0,0 +1,4 @@ +[Metadata] + +Title: Beatmap with no header +Creator: Incredibly Evil Hacker diff --git a/osu.Game.Tests/Resources/no-empty-line-after-header.osu b/osu.Game.Tests/Resources/no-empty-line-after-header.osu new file mode 100644 index 0000000000..9db2b7c01c --- /dev/null +++ b/osu.Game.Tests/Resources/no-empty-line-after-header.osu @@ -0,0 +1,4 @@ +osu file format v14 +[Metadata] +Title: No empty line delimiting header from contents +Creator: Edge Case Hunter \ No newline at end of file diff --git a/osu.Game.Tests/osu.Game.Tests.csproj b/osu.Game.Tests/osu.Game.Tests.csproj index 84f67c9319..9dc3e85e1b 100644 --- a/osu.Game.Tests/osu.Game.Tests.csproj +++ b/osu.Game.Tests/osu.Game.Tests.csproj @@ -1,5 +1,12 @@  + + + + + + + diff --git a/osu.Game/Beatmaps/Formats/Decoder.cs b/osu.Game/Beatmaps/Formats/Decoder.cs index 0f1b617809..4a539cc33f 100644 --- a/osu.Game/Beatmaps/Formats/Decoder.cs +++ b/osu.Game/Beatmaps/Formats/Decoder.cs @@ -28,6 +28,7 @@ namespace osu.Game.Beatmaps.Formats public abstract class Decoder { private static readonly Dictionary>> decoders = new Dictionary>>(); + private static readonly Dictionary> fallback_decoders = new Dictionary>(); static Decoder() { @@ -49,21 +50,31 @@ namespace osu.Game.Beatmaps.Formats if (!decoders.TryGetValue(typeof(T), out var typedDecoders)) throw new IOException(@"Unknown decoder type"); - string line; + // start off with the first line of the file + string line = stream.PeekLine()?.Trim(); - do + while (line != null && line.Length == 0) { - line = stream.ReadLine()?.Trim(); - } while (line != null && line.Length == 0); + // consume the previously peeked empty line and advance to the next one + stream.ReadLine(); + line = stream.PeekLine()?.Trim(); + } if (line == null) - throw new IOException(@"Unknown file format (null)"); + throw new IOException("Unknown file format (null)"); var decoder = typedDecoders.Select(d => line.StartsWith(d.Key, StringComparison.InvariantCulture) ? d.Value : null).FirstOrDefault(); - if (decoder == null) - throw new IOException($@"Unknown file format ({line})"); - return (Decoder)decoder.Invoke(line); + // it's important the magic does NOT get consumed here, since sometimes it's part of the structure + // (see JsonBeatmapDecoder - the magic string is the opening brace) + // decoder implementations should therefore not die on receiving their own magic + if (decoder != null) + return (Decoder)decoder.Invoke(line); + + if (!fallback_decoders.TryGetValue(typeof(T), out var fallbackDecoder)) + throw new IOException($"Unknown file format ({line})"); + + return (Decoder)fallbackDecoder.Invoke(); } /// @@ -78,5 +89,19 @@ namespace osu.Game.Beatmaps.Formats typedDecoders[magic] = constructor; } + + /// + /// Registers a fallback decoder instantiation function. + /// The fallback will be returned if the first line of the decoded stream does not match any known magic. + /// + /// Type of object being decoded. + /// A function that constructs the fallback. + protected static void SetFallbackDecoder(Func constructor) + { + if (fallback_decoders.ContainsKey(typeof(T))) + throw new InvalidOperationException($"A fallback decoder was already added for type {typeof(T)}."); + + fallback_decoders[typeof(T)] = constructor; + } } } diff --git a/osu.Game/Beatmaps/Formats/LegacyBeatmapDecoder.cs b/osu.Game/Beatmaps/Formats/LegacyBeatmapDecoder.cs index 6e34fd8e90..786b7611b5 100644 --- a/osu.Game/Beatmaps/Formats/LegacyBeatmapDecoder.cs +++ b/osu.Game/Beatmaps/Formats/LegacyBeatmapDecoder.cs @@ -26,6 +26,7 @@ namespace osu.Game.Beatmaps.Formats public static void Register() { AddDecoder(@"osu file format v", m => new LegacyBeatmapDecoder(Parsing.ParseInt(m.Split('v').Last()))); + SetFallbackDecoder(() => new LegacyBeatmapDecoder()); } /// diff --git a/osu.Game/Beatmaps/Formats/LegacyStoryboardDecoder.cs b/osu.Game/Beatmaps/Formats/LegacyStoryboardDecoder.cs index a8f8dbf69d..5dbd67d304 100644 --- a/osu.Game/Beatmaps/Formats/LegacyStoryboardDecoder.cs +++ b/osu.Game/Beatmaps/Formats/LegacyStoryboardDecoder.cs @@ -34,6 +34,7 @@ namespace osu.Game.Beatmaps.Formats // note that this isn't completely correct AddDecoder(@"osu file format v", m => new LegacyStoryboardDecoder()); AddDecoder(@"[Events]", m => new LegacyStoryboardDecoder()); + SetFallbackDecoder(() => new LegacyStoryboardDecoder()); } protected override void ParseStreamInto(LineBufferedReader stream, Storyboard storyboard) diff --git a/osu.Game/IO/LineBufferedReader.cs b/osu.Game/IO/LineBufferedReader.cs index 66dee1181f..aab761afd8 100644 --- a/osu.Game/IO/LineBufferedReader.cs +++ b/osu.Game/IO/LineBufferedReader.cs @@ -25,6 +25,7 @@ namespace osu.Game.IO /// /// Reads the next line from the stream without consuming it. + /// Subsequent calls to without a will return the same string. /// public string PeekLine() { @@ -39,6 +40,7 @@ namespace osu.Game.IO /// /// Reads the next line from the stream and consumes it. + /// If a line was peeked, that same line will then be consumed and returned. /// public string ReadLine() => lineBuffer.Count > 0 ? lineBuffer.Dequeue() : streamReader.ReadLine();