Rename BeatmapCollectionManager -> CollectionManager

osu.Game/Collections/CollectionManager.cs

@@ -0,0 +1,325 @@
+// 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;
+using System.Collections.Generic;
+using System.Collections.Specialized;
+using System.IO;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using osu.Framework;
+using osu.Framework.Allocation;
+using osu.Framework.Bindables;
+using osu.Framework.Graphics;
+using osu.Framework.Logging;
+using osu.Framework.Platform;
+using osu.Game.Beatmaps;
+using osu.Game.IO.Legacy;
+using osu.Game.Overlays.Notifications;
+
+namespace osu.Game.Collections
+{
+    /// <summary>
+    /// Handles user-defined collections of beatmaps.
+    /// </summary>
+    /// <remarks>
+    /// This is currently reading and writing from the osu-stable file format. This is a temporary arrangement until we refactor the
+    /// database backing the game. Going forward writing should be done in a similar way to other model stores.
+    /// </remarks>
+    public class CollectionManager : Component
+    {
+        /// <summary>
+        /// Database version in stable-compatible YYYYMMDD format.
+        /// </summary>
+        private const int database_version = 30000000;
+
+        private const string database_name = "collection.db";
+
+        public readonly BindableList<BeatmapCollection> Collections = new BindableList<BeatmapCollection>();
+
+        public bool SupportsImportFromStable => RuntimeInfo.IsDesktop;
+
+        /// <summary>
+        /// Whether the user's database has finished loading.
+        /// </summary>
+        public bool DatabaseLoaded { get; private set; }
+
+        [Resolved]
+        private GameHost host { get; set; }
+
+        [Resolved]
+        private BeatmapManager beatmaps { get; set; }
+
+        private readonly Storage storage;
+
+        public CollectionManager(Storage storage)
+        {
+            this.storage = storage;
+        }
+
+        [BackgroundDependencyLoader]
+        private void load()
+        {
+            Collections.CollectionChanged += collectionsChanged;
+            loadDatabase();
+        }
+
+        private void collectionsChanged(object sender, NotifyCollectionChangedEventArgs e)
+        {
+            switch (e.Action)
+            {
+                case NotifyCollectionChangedAction.Add:
+                    foreach (var c in e.NewItems.Cast<BeatmapCollection>())
+                        c.Changed += backgroundSave;
+                    break;
+
+                case NotifyCollectionChangedAction.Remove:
+                    foreach (var c in e.OldItems.Cast<BeatmapCollection>())
+                        c.Changed -= backgroundSave;
+                    break;
+
+                case NotifyCollectionChangedAction.Replace:
+                    foreach (var c in e.OldItems.Cast<BeatmapCollection>())
+                        c.Changed -= backgroundSave;
+
+                    foreach (var c in e.NewItems.Cast<BeatmapCollection>())
+                        c.Changed += backgroundSave;
+                    break;
+            }
+
+            backgroundSave();
+        }
+
+        private void loadDatabase() => Task.Run(async () =>
+        {
+            if (storage.Exists(database_name))
+            {
+                using (var stream = storage.GetStream(database_name))
+                    await import(stream);
+            }
+
+            DatabaseLoaded = true;
+        });
+
+        /// <summary>
+        /// Set an endpoint for notifications to be posted to.
+        /// </summary>
+        public Action<Notification> PostNotification { protected get; set; }
+
+        /// <summary>
+        /// Set a storage with access to an osu-stable install for import purposes.
+        /// </summary>
+        public Func<Storage> GetStableStorage { private get; set; }
+
+        /// <summary>
+        /// This is a temporary method and will likely be replaced by a full-fledged (and more correctly placed) migration process in the future.
+        /// </summary>
+        public Task ImportFromStableAsync()
+        {
+            var stable = GetStableStorage?.Invoke();
+
+            if (stable == null)
+            {
+                Logger.Log("No osu!stable installation available!", LoggingTarget.Information, LogLevel.Error);
+                return Task.CompletedTask;
+            }
+
+            if (!stable.Exists(database_name))
+            {
+                // This handles situations like when the user does not have a collections.db file
+                Logger.Log($"No {database_name} available in osu!stable installation", LoggingTarget.Information, LogLevel.Error);
+                return Task.CompletedTask;
+            }
+
+            return Task.Run(async () =>
+            {
+                using (var stream = stable.GetStream(database_name))
+                    await Import(stream);
+            });
+        }
+
+        public async Task Import(Stream stream)
+        {
+            var notification = new ProgressNotification
+            {
+                State = ProgressNotificationState.Active,
+                Text = "Collections import is initialising..."
+            };
+
+            PostNotification?.Invoke(notification);
+
+            await import(stream, notification);
+        }
+
+        private async Task import(Stream stream, ProgressNotification notification = null) => await Task.Run(async () =>
+        {
+            if (notification != null)
+                notification.Progress = 0;
+
+            var collection = readCollections(stream, notification);
+            bool importCompleted = false;
+
+            Schedule(() =>
+            {
+                importCollections(collection);
+                importCompleted = true;
+            });
+
+            while (!IsDisposed && !importCompleted)
+                await Task.Delay(10);
+
+            if (notification != null)
+            {
+                notification.CompletionText = $"Imported {collection.Count} collections";
+                notification.State = ProgressNotificationState.Completed;
+            }
+        });
+
+        private void importCollections(List<BeatmapCollection> newCollections)
+        {
+            foreach (var newCol in newCollections)
+            {
+                var existing = Collections.FirstOrDefault(c => c.Name == newCol.Name);
+                if (existing == null)
+                    Collections.Add(existing = new BeatmapCollection { Name = { Value = newCol.Name.Value } });
+
+                foreach (var newBeatmap in newCol.Beatmaps)
+                {
+                    if (!existing.Beatmaps.Contains(newBeatmap))
+                        existing.Beatmaps.Add(newBeatmap);
+                }
+            }
+        }
+
+        private List<BeatmapCollection> readCollections(Stream stream, ProgressNotification notification = null)
+        {
+            if (notification != null)
+            {
+                notification.Text = "Reading collections...";
+                notification.Progress = 0;
+            }
+
+            var result = new List<BeatmapCollection>();
+
+            try
+            {
+                using (var sr = new SerializationReader(stream))
+                {
+                    sr.ReadInt32(); // Version
+
+                    int collectionCount = sr.ReadInt32();
+                    result.Capacity = collectionCount;
+
+                    for (int i = 0; i < collectionCount; i++)
+                    {
+                        if (notification?.CancellationToken.IsCancellationRequested == true)
+                            return result;
+
+                        var collection = new BeatmapCollection { Name = { Value = sr.ReadString() } };
+                        int mapCount = sr.ReadInt32();
+
+                        for (int j = 0; j < mapCount; j++)
+                        {
+                            if (notification?.CancellationToken.IsCancellationRequested == true)
+                                return result;
+
+                            string checksum = sr.ReadString();
+
+                            var beatmap = beatmaps.QueryBeatmap(b => b.MD5Hash == checksum);
+                            if (beatmap != null)
+                                collection.Beatmaps.Add(beatmap);
+                        }
+
+                        if (notification != null)
+                        {
+                            notification.Text = $"Imported {i + 1} of {collectionCount} collections";
+                            notification.Progress = (float)(i + 1) / collectionCount;
+                        }
+
+                        result.Add(collection);
+                    }
+                }
+            }
+            catch (Exception e)
+            {
+                Logger.Error(e, "Failed to read collection database.");
+            }
+
+            return result;
+        }
+
+        public void DeleteAll()
+        {
+            Collections.Clear();
+            PostNotification?.Invoke(new SimpleNotification { Text = "Deleted all collections!" });
+        }
+
+        private readonly object saveLock = new object();
+        private int lastSave;
+        private int saveFailures;
+
+        /// <summary>
+        /// Perform a save with debounce.
+        /// </summary>
+        private void backgroundSave()
+        {
+            var current = Interlocked.Increment(ref lastSave);
+            Task.Delay(100).ContinueWith(task =>
+            {
+                if (current != lastSave)
+                    return;
+
+                if (!save())
+                    backgroundSave();
+            });
+        }
+
+        private bool save()
+        {
+            lock (saveLock)
+            {
+                Interlocked.Increment(ref lastSave);
+
+                try
+                {
+                    // This is NOT thread-safe!!
+
+                    using (var sw = new SerializationWriter(storage.GetStream(database_name, FileAccess.Write)))
+                    {
+                        sw.Write(database_version);
+                        sw.Write(Collections.Count);
+
+                        foreach (var c in Collections)
+                        {
+                            sw.Write(c.Name.Value);
+                            sw.Write(c.Beatmaps.Count);
+
+                            foreach (var b in c.Beatmaps)
+                                sw.Write(b.MD5Hash);
+                        }
+                    }
+
+                    if (saveFailures < 10)
+                        saveFailures = 0;
+                    return true;
+                }
+                catch (Exception e)
+                {
+                    // Since this code is not thread-safe, we may run into random exceptions (such as collection enumeration or out of range indexing).
+                    // Failures are thus only alerted if they exceed a threshold (once) to indicate "actual" errors having occurred.
+                    if (++saveFailures == 10)
+                        Logger.Error(e, "Failed to save collection database!");
+                }
+
+                return false;
+            }
+        }
+
+        protected override void Dispose(bool isDisposing)
+        {
+            base.Dispose(isDisposing);
+            save();
+        }
+    }
+}