Add too short audio files check and tests

osu.Game/Rulesets/Edit/Checks/CheckTooShortAudioFiles.cs

@@ -0,0 +1,83 @@
+// 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.Collections.Generic;
+using System.IO;
+using System.Linq;
+using ManagedBass;
+using osu.Framework.Audio.Callbacks;
+using osu.Game.Rulesets.Edit.Checks.Components;
+
+namespace osu.Game.Rulesets.Edit.Checks
+{
+    public class CheckTooShortAudioFiles : ICheck
+    {
+        private const int ms_threshold = 25;
+        private const int min_bytes_threshold = 100;
+
+        private readonly string[] audioExtensions = { "mp3", "ogg", "wav" };
+
+        public CheckMetadata Metadata => new CheckMetadata(CheckCategory.Audio, "Too short audio files");
+
+        public IEnumerable<IssueTemplate> PossibleTemplates => new IssueTemplate[]
+        {
+            new IssueTemplateTooShort(this),
+            new IssueTemplateBadFormat(this)
+        };
+
+        public IEnumerable<Issue> Run(BeatmapVerifierContext context)
+        {
+            var beatmapSet = context.Beatmap.BeatmapInfo.BeatmapSet;
+
+            foreach (var file in beatmapSet.Files)
+            {
+                Stream data = context.WorkingBeatmap.GetStream(file.FileInfo.StoragePath);
+                if (data == null)
+                    continue;
+
+                var fileCallbacks = new FileCallbacks(new DataStreamFileProcedures(data));
+                int decodeStream = Bass.CreateStream(StreamSystem.NoBuffer, BassFlags.Decode, fileCallbacks.Callbacks, fileCallbacks.Handle);
+
+                if (decodeStream == 0)
+                {
+                    // If the file is not likely to be properly parsed by Bass, we don't produce Error issues about it.
+                    // Image files and audio files devoid of audio data both fail, for example, but neither would be issues in this check.
+                    if (hasAudioExtension(file.Filename) && probablyHasAudioData(data))
+                        yield return new IssueTemplateBadFormat(this).Create(file.Filename);
+
+                    continue;
+                }
+
+                long length = Bass.ChannelGetLength(decodeStream);
+                double ms = Bass.ChannelBytes2Seconds(decodeStream, length) * 1000;
+
+                // Extremely short audio files do not play on some soundcards, resulting in nothing being heard in-game for some users.
+                if (ms > 0 && ms < ms_threshold)
+                    yield return new IssueTemplateTooShort(this).Create(file.Filename, ms);
+            }
+        }
+
+        private bool hasAudioExtension(string filename) => audioExtensions.Any(filename.ToLower().EndsWith);
+        private bool probablyHasAudioData(Stream data) => data.Length > min_bytes_threshold;
+
+        public class IssueTemplateTooShort : IssueTemplate
+        {
+            public IssueTemplateTooShort(ICheck check)
+                : base(check, IssueType.Problem, "\"{0}\" is too short ({1:0f} ms), should be at least {2:0f} ms.")
+            {
+            }
+
+            public Issue Create(string filename, double ms) => new Issue(this, filename, ms, ms_threshold);
+        }
+
+        public class IssueTemplateBadFormat : IssueTemplate
+        {
+            public IssueTemplateBadFormat(ICheck check)
+                : base(check, IssueType.Error, "Could not check whether \"{0}\" is too short (code \"{1}\").")
+            {
+            }
+
+            public Issue Create(string filename) => new Issue(this, filename, Bass.LastError);
+        }
+    }
+}