Move remaining realm classes out of Stores namespace

osu.Game/Database/RealmFileStore.cs

@@ -0,0 +1,122 @@
+// 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 enable
+
+using System;
+using System.IO;
+using System.Linq;
+using osu.Framework.Extensions;
+using osu.Framework.IO.Stores;
+using osu.Framework.Logging;
+using osu.Framework.Platform;
+using osu.Framework.Testing;
+using osu.Game.Extensions;
+using osu.Game.Models;
+using Realms;
+
+namespace osu.Game.Database
+{
+    /// <summary>
+    /// Handles the storing of files to the file system (and database) backing.
+    /// </summary>
+    [ExcludeFromDynamicCompile]
+    public class RealmFileStore
+    {
+        private readonly RealmAccess realm;
+
+        public readonly IResourceStore<byte[]> Store;
+
+        public readonly Storage Storage;
+
+        public RealmFileStore(RealmAccess realm, Storage storage)
+        {
+            this.realm = realm;
+
+            Storage = storage.GetStorageForDirectory(@"files");
+            Store = new StorageBackedResourceStore(Storage);
+        }
+
+        /// <summary>
+        /// Add a new file to the game-wide database, copying it to permanent storage if not already present.
+        /// </summary>
+        /// <param name="data">The file data stream.</param>
+        /// <param name="realm">The realm instance to add to. Should already be in a transaction.</param>
+        /// <returns></returns>
+        public RealmFile Add(Stream data, Realm realm)
+        {
+            string hash = data.ComputeSHA2Hash();
+
+            var existing = realm.Find<RealmFile>(hash);
+
+            var file = existing ?? new RealmFile { Hash = hash };
+
+            if (!checkFileExistsAndMatchesHash(file))
+                copyToStore(file, data);
+
+            if (!file.IsManaged)
+                realm.Add(file);
+
+            return file;
+        }
+
+        private void copyToStore(RealmFile file, Stream data)
+        {
+            data.Seek(0, SeekOrigin.Begin);
+
+            using (var output = Storage.CreateFileSafely(file.GetStoragePath()))
+                data.CopyTo(output);
+
+            data.Seek(0, SeekOrigin.Begin);
+        }
+
+        private bool checkFileExistsAndMatchesHash(RealmFile file)
+        {
+            string path = file.GetStoragePath();
+
+            // we may be re-adding a file to fix missing store entries.
+            if (!Storage.Exists(path))
+                return false;
+
+            // even if the file already exists, check the existing checksum for safety.
+            using (var stream = Storage.GetStream(path))
+                return stream.ComputeSHA2Hash() == file.Hash;
+        }
+
+        public void Cleanup()
+        {
+            Logger.Log(@"Beginning realm file store cleanup");
+
+            int totalFiles = 0;
+            int removedFiles = 0;
+
+            // can potentially be run asynchronously, although we will need to consider operation order for disk deletion vs realm removal.
+            realm.Write(r =>
+            {
+                // TODO: consider using a realm native query to avoid iterating all files (https://github.com/realm/realm-dotnet/issues/2659#issuecomment-927823707)
+                var files = r.All<RealmFile>().ToList();
+
+                foreach (var file in files)
+                {
+                    totalFiles++;
+
+                    if (file.BacklinksCount > 0)
+                        continue;
+
+                    try
+                    {
+                        removedFiles++;
+                        Storage.Delete(file.GetStoragePath());
+                        r.Remove(file);
+                    }
+                    catch (Exception e)
+                    {
+                        Logger.Error(e, $@"Could not delete databased file {file.Hash}");
+                    }
+                }
+            });
+
+            Logger.Log($@"Finished realm file store cleanup ({removedFiles} of {totalFiles} deleted)");
+        }
+    }
+}