Migrate the majority of existing file lookups to use new extension methods

osu.Game/Beatmaps/BeatmapInfo.cs

@@ -199,8 +199,8 @@ namespace osu.Game.Beatmaps
             Debug.Assert(x.BeatmapSet != null);
             Debug.Assert(y.BeatmapSet != null);
 
-            string? fileHashX = x.BeatmapSet.Files.FirstOrDefault(f => f.Filename == getFilename(x.Metadata))?.File.Hash;
+            string? fileHashX = x.BeatmapSet.GetFile(getFilename(x.Metadata))?.File.Hash;
-            string? fileHashY = y.BeatmapSet.Files.FirstOrDefault(f => f.Filename == getFilename(y.Metadata))?.File.Hash;
+            string? fileHashY = y.BeatmapSet.GetFile(getFilename(y.Metadata))?.File.Hash;
 
             return fileHashX == fileHashY;
         }

osu.Game/Beatmaps/BeatmapManager.cs

@@ -300,7 +300,7 @@ namespace osu.Game.Beatmaps
                 stream.Seek(0, SeekOrigin.Begin);
 
                 // AddFile generally handles updating/replacing files, but this is a case where the filename may have also changed so let's delete for simplicity.
-                var existingFileInfo = setInfo.Files.SingleOrDefault(f => string.Equals(f.Filename, beatmapInfo.Path, StringComparison.OrdinalIgnoreCase));
+                var existingFileInfo = beatmapInfo.Path != null ? setInfo.GetFile(beatmapInfo.Path) : null;
                 string targetFilename = createBeatmapFilenameFromMetadata(beatmapInfo);
 
                 // ensure that two difficulties from the set don't point at the same beatmap file.

osu.Game/Beatmaps/BeatmapSetInfo.cs

@@ -84,13 +84,6 @@ namespace osu.Game.Beatmaps
         {
         }
 
-        /// <summary>
-        /// Returns the storage path for the file in this beatmapset with the given filename, if any exists, otherwise null.
-        /// The path returned is relative to the user file storage.
-        /// </summary>
-        /// <param name="filename">The name of the file to get the storage path of.</param>
-        public string? GetPathForFile(string filename) => Files.SingleOrDefault(f => string.Equals(f.Filename, filename, StringComparison.OrdinalIgnoreCase))?.File.GetStoragePath();
-
         public bool Equals(BeatmapSetInfo? other)
         {
             if (ReferenceEquals(this, other)) return true;

osu.Game/Database/IHasRealmFiles.cs

@@ -2,6 +2,7 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using System.Collections.Generic;
+using osu.Game.Beatmaps;
 using osu.Game.Models;
 
 namespace osu.Game.Database
@@ -11,8 +12,16 @@ namespace osu.Game.Database
     /// </summary>
     public interface IHasRealmFiles
     {
+        /// <summary>
+        /// Available files in this model, with locally filenames.
+        /// When performing lookups, consider using <see cref="HasRealmFilesExtensions.GetFile"/> or <see cref="HasRealmFilesExtensions.GetPathForFile"/> to do case-insensitive lookups.
+        /// </summary>
         IList<RealmNamedFileUsage> Files { get; }
 
+        /// <summary>
+        /// A combined hash representing the model, based on the files it contains.
+        /// Implementation specific.
+        /// </summary>
         string Hash { get; set; }
     }
 }

osu.Game/Database/ModelManager.cs

@@ -7,6 +7,7 @@ using System.Diagnostics;
 using System.IO;
 using System.Linq;
 using osu.Framework.Platform;
+using osu.Game.Beatmaps;
 using osu.Game.Extensions;
 using osu.Game.Models;
 using osu.Game.Overlays.Notifications;
@@ -79,7 +80,7 @@ namespace osu.Game.Database
         /// </summary>
         public void AddFile(TModel item, Stream contents, string filename, Realm realm)
         {
-            var existing = item.Files.FirstOrDefault(f => string.Equals(f.Filename, filename, StringComparison.OrdinalIgnoreCase));
+            var existing = item.GetFile(filename);
 
             if (existing != null)
             {

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

@@ -5,6 +5,7 @@
 
 using System.Collections.Generic;
 using System.IO;
+using osu.Game.Beatmaps;
 using osu.Game.IO.FileAbstraction;
 using osu.Game.Rulesets.Edit.Checks.Components;
 using osu.Game.Storyboards;

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

@@ -5,6 +5,7 @@
 
 using System.Collections.Generic;
 using System.IO;
+using osu.Game.Beatmaps;
 using osu.Game.Rulesets.Edit.Checks.Components;
 
 namespace osu.Game.Rulesets.Edit.Checks

osu.Game/Screens/Edit/Setup/ResourcesSection.cs

@@ -4,7 +4,6 @@
 #nullable disable
 
 using System.IO;
-using System.Linq;
 using osu.Framework.Allocation;
 using osu.Framework.Bindables;
 using osu.Framework.Graphics;
@@ -78,7 +77,7 @@ namespace osu.Game.Screens.Edit.Setup
 
             // remove the previous background for now.
             // in the future we probably want to check if this is being used elsewhere (other difficulties?)
-            var oldFile = set.Files.FirstOrDefault(f => f.Filename == working.Value.Metadata.BackgroundFile);
+            var oldFile = set.GetFile(working.Value.Metadata.BackgroundFile);
 
             using (var stream = source.OpenRead())
             {
@@ -107,7 +106,7 @@ namespace osu.Game.Screens.Edit.Setup
 
             // remove the previous audio track for now.
             // in the future we probably want to check if this is being used elsewhere (other difficulties?)
-            var oldFile = set.Files.FirstOrDefault(f => f.Filename == working.Value.Metadata.AudioFile);
+            var oldFile = set.GetFile(working.Value.Metadata.AudioFile);
 
             using (var stream = source.OpenRead())
             {

osu.Game/Skinning/SkinImporter.cs

@@ -10,6 +10,7 @@ using System.Threading;
 using Newtonsoft.Json;
 using osu.Framework.Logging;
 using osu.Framework.Platform;
+using osu.Game.Beatmaps;
 using osu.Game.Database;
 using osu.Game.Extensions;
 using osu.Game.IO;
@@ -49,7 +50,7 @@ namespace osu.Game.Skinning
 
         protected override void Populate(SkinInfo model, ArchiveReader? archive, Realm realm, CancellationToken cancellationToken = default)
         {
-            var skinInfoFile = model.Files.SingleOrDefault(f => f.Filename == skin_info_file);
+            var skinInfoFile = model.GetFile(skin_info_file);
 
             if (skinInfoFile != null)
             {
@@ -129,7 +130,7 @@ namespace osu.Game.Skinning
                 authorLine,
             };
 
-            var existingFile = item.Files.SingleOrDefault(f => f.Filename.Equals(@"skin.ini", StringComparison.OrdinalIgnoreCase));
+            var existingFile = item.GetFile(@"skin.ini");
 
             if (existingFile == null)
             {
@@ -163,7 +164,7 @@ namespace osu.Game.Skinning
                     {
                         Logger.Log($"Skin {item}'s skin.ini had issues and has been removed. Please report this and provide the problematic skin.", LoggingTarget.Database, LogLevel.Important);
 
-                        var existingIni = item.Files.SingleOrDefault(f => f.Filename.Equals(@"skin.ini", StringComparison.OrdinalIgnoreCase));
+                        var existingIni = item.GetFile(@"skin.ini");
                         if (existingIni != null)
                             item.Files.Remove(existingIni);
 
@@ -248,7 +249,7 @@ namespace osu.Game.Skinning
                     {
                         string filename = @$"{drawableInfo.Key}.json";
 
-                        var oldFile = s.Files.FirstOrDefault(f => f.Filename == filename);
+                        var oldFile = s.GetFile(filename);
 
                         if (oldFile != null)
                             modelManager.ReplaceFile(oldFile, streamContent, s.Realm);

osu.Game/Storyboards/Drawables/DrawableStoryboardVideo.cs

@@ -1,10 +1,6 @@
 // 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.
 
-#nullable disable
-
-using System;
-using System.Linq;
 using osu.Framework.Allocation;
 using osu.Framework.Bindables;
 using osu.Framework.Graphics;
@@ -12,14 +8,14 @@ using osu.Framework.Graphics.Containers;
 using osu.Framework.Graphics.Textures;
 using osu.Framework.Graphics.Video;
 using osu.Game.Beatmaps;
-using osu.Game.Extensions;
 
 namespace osu.Game.Storyboards.Drawables
 {
     public class DrawableStoryboardVideo : CompositeDrawable
     {
         public readonly StoryboardVideo Video;
-        private Video video;
+
+        private Video? drawableVideo;
 
         public override bool RemoveWhenNotAlive => false;
 
@@ -33,7 +29,7 @@ namespace osu.Game.Storyboards.Drawables
         [BackgroundDependencyLoader(true)]
         private void load(IBindable<WorkingBeatmap> beatmap, TextureStore textureStore)
         {
-            string path = beatmap.Value.BeatmapSetInfo?.Files.FirstOrDefault(f => f.Filename.Equals(Video.Path, StringComparison.OrdinalIgnoreCase))?.File.GetStoragePath();
+            string? path = beatmap.Value.BeatmapSetInfo?.GetPathForFile(Video.Path);
 
             if (path == null)
                 return;
@@ -43,7 +39,7 @@ namespace osu.Game.Storyboards.Drawables
             if (stream == null)
                 return;
 
-            InternalChild = video = new Video(stream, false)
+            InternalChild = drawableVideo = new Video(stream, false)
             {
                 RelativeSizeAxes = Axes.Both,
                 FillMode = FillMode.Fill,
@@ -57,12 +53,12 @@ namespace osu.Game.Storyboards.Drawables
         {
             base.LoadComplete();
 
-            if (video == null) return;
+            if (drawableVideo == null) return;
 
-            using (video.BeginAbsoluteSequence(Video.StartTime))
+            using (drawableVideo.BeginAbsoluteSequence(Video.StartTime))
             {
-                Schedule(() => video.PlaybackPosition = Time.Current - Video.StartTime);
+                Schedule(() => drawableVideo.PlaybackPosition = Time.Current - Video.StartTime);
-                video.FadeIn(500);
+                drawableVideo.FadeIn(500);
             }
         }
     }

osu.Game/Storyboards/Storyboard.cs

@@ -1,14 +1,10 @@
 // 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.
 
-#nullable disable
-
-using System;
 using System.Collections.Generic;
 using System.Linq;
 using osu.Framework.Graphics.Textures;
 using osu.Game.Beatmaps;
-using osu.Game.Extensions;
 using osu.Game.Rulesets.Mods;
 using osu.Game.Storyboards.Drawables;
 
@@ -90,12 +86,12 @@ namespace osu.Game.Storyboards
             }
         }
 
-        public DrawableStoryboard CreateDrawable(IReadOnlyList<Mod> mods = null) =>
+        public DrawableStoryboard CreateDrawable(IReadOnlyList<Mod>? mods = null) =>
             new DrawableStoryboard(this, mods);
 
-        public Texture GetTextureFromPath(string path, TextureStore textureStore)
+        public Texture? GetTextureFromPath(string path, TextureStore textureStore)
         {
-            string storyboardPath = BeatmapInfo.BeatmapSet?.Files.FirstOrDefault(f => f.Filename.Equals(path, StringComparison.OrdinalIgnoreCase))?.File.GetStoragePath();
+            string? storyboardPath = BeatmapInfo.BeatmapSet?.GetPathForFile(path);
 
             if (!string.IsNullOrEmpty(storyboardPath))
                 return textureStore.Get(storyboardPath);