Rename class and extract out lookup method

osu.Game/Beatmaps/BeatmapManager_BeatmapOnlineLookupQueue.cs

@@ -0,0 +1,193 @@
+// 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.Diagnostics.CodeAnalysis;
+using System.IO;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using Dapper;
+using Microsoft.Data.Sqlite;
+using osu.Framework.IO.Network;
+using osu.Framework.Logging;
+using osu.Framework.Platform;
+using osu.Framework.Threading;
+using osu.Game.Online.API;
+using osu.Game.Online.API.Requests;
+using SharpCompress.Compressors;
+using SharpCompress.Compressors.BZip2;
+
+namespace osu.Game.Beatmaps
+{
+    public partial class BeatmapManager
+    {
+        private class BeatmapOnlineLookupQueue
+        {
+            private readonly IAPIProvider api;
+            private readonly Storage storage;
+
+            private const int update_queue_request_concurrency = 4;
+
+            private readonly ThreadedTaskScheduler updateScheduler = new ThreadedTaskScheduler(update_queue_request_concurrency, nameof(BeatmapOnlineLookupQueue));
+
+            private FileWebRequest cacheDownloadRequest;
+
+            private const string cache_database_name = "online.db";
+
+            public BeatmapOnlineLookupQueue(IAPIProvider api, Storage storage)
+            {
+                this.api = api;
+                this.storage = storage;
+
+                if (!storage.Exists(cache_database_name))
+                    prepareLocalCache();
+            }
+
+            public Task UpdateAsync(BeatmapSetInfo beatmapSet, CancellationToken cancellationToken)
+            {
+                if (api?.State != APIState.Online)
+                    return Task.CompletedTask;
+
+                LogForModel(beatmapSet, "Performing online lookups...");
+                return Task.WhenAll(beatmapSet.Beatmaps.Select(b => UpdateAsync(beatmapSet, b, cancellationToken)).ToArray());
+            }
+
+            // todo: expose this when we need to do individual difficulty lookups.
+            protected Task UpdateAsync(BeatmapSetInfo beatmapSet, BeatmapInfo beatmap, CancellationToken cancellationToken)
+                => Task.Factory.StartNew(() => lookup(beatmapSet, beatmap), cancellationToken, TaskCreationOptions.HideScheduler, updateScheduler);
+
+            private void lookup(BeatmapSetInfo set, BeatmapInfo beatmap)
+            {
+                if (checkLocalCache(set, beatmap))
+                    return;
+
+                if (api?.State != APIState.Online)
+                    return;
+
+                var req = new GetBeatmapRequest(beatmap);
+
+                req.Failure += fail;
+
+                try
+                {
+                    // intentionally blocking to limit web request concurrency
+                    api.Perform(req);
+
+                    var res = req.Result;
+
+                    if (res != null)
+                    {
+                        beatmap.Status = res.Status;
+                        beatmap.BeatmapSet.Status = res.BeatmapSet.Status;
+                        beatmap.BeatmapSet.OnlineBeatmapSetID = res.OnlineBeatmapSetID;
+                        beatmap.OnlineBeatmapID = res.OnlineBeatmapID;
+
+                        LogForModel(set, $"Online retrieval mapped {beatmap} to {res.OnlineBeatmapSetID} / {res.OnlineBeatmapID}.");
+                    }
+                }
+                catch (Exception e)
+                {
+                    fail(e);
+                }
+
+                void fail(Exception e)
+                {
+                    beatmap.OnlineBeatmapID = null;
+                    LogForModel(set, $"Online retrieval failed for {beatmap} ({e.Message})");
+                }
+            }
+
+            private void prepareLocalCache()
+            {
+                string cacheFilePath = storage.GetFullPath(cache_database_name);
+                string compressedCacheFilePath = $"{cacheFilePath}.bz2";
+
+                cacheDownloadRequest = new FileWebRequest(compressedCacheFilePath, $"https://assets.ppy.sh/client-resources/{cache_database_name}.bz2");
+
+                cacheDownloadRequest.Failed += ex =>
+                {
+                    File.Delete(compressedCacheFilePath);
+                    File.Delete(cacheFilePath);
+
+                    Logger.Log($"{nameof(BeatmapOnlineLookupQueue)}'s online cache download failed: {ex}", LoggingTarget.Database);
+                };
+
+                cacheDownloadRequest.Finished += () =>
+                {
+                    try
+                    {
+                        using (var stream = File.OpenRead(cacheDownloadRequest.Filename))
+                        using (var outStream = File.OpenWrite(cacheFilePath))
+                        using (var bz2 = new BZip2Stream(stream, CompressionMode.Decompress, false))
+                            bz2.CopyTo(outStream);
+
+                        // set to null on completion to allow lookups to begin using the new source
+                        cacheDownloadRequest = null;
+                    }
+                    catch (Exception ex)
+                    {
+                        Logger.Log($"{nameof(BeatmapOnlineLookupQueue)}'s online cache extraction failed: {ex}", LoggingTarget.Database);
+                        File.Delete(cacheFilePath);
+                    }
+                    finally
+                    {
+                        File.Delete(compressedCacheFilePath);
+                    }
+                };
+
+                cacheDownloadRequest.PerformAsync();
+            }
+
+            private bool checkLocalCache(BeatmapSetInfo set, BeatmapInfo beatmap)
+            {
+                // download is in progress (or was, and failed).
+                if (cacheDownloadRequest != null)
+                    return false;
+
+                // database is unavailable.
+                if (!storage.Exists(cache_database_name))
+                    return false;
+
+                try
+                {
+                    using (var db = new SqliteConnection(storage.GetDatabaseConnectionString("online")))
+                    {
+                        var found = db.QuerySingleOrDefault<CachedOnlineBeatmapLookup>(
+                            "SELECT * FROM osu_beatmaps WHERE checksum = @MD5Hash OR beatmap_id = @OnlineBeatmapID OR filename = @Path", beatmap);
+
+                        if (found != null)
+                        {
+                            var status = (BeatmapSetOnlineStatus)found.approved;
+
+                            beatmap.Status = status;
+                            beatmap.BeatmapSet.Status = status;
+                            beatmap.BeatmapSet.OnlineBeatmapSetID = found.beatmapset_id;
+                            beatmap.OnlineBeatmapID = found.beatmap_id;
+
+                            LogForModel(set, $"Cached local retrieval for {beatmap}.");
+                            return true;
+                        }
+                    }
+                }
+                catch (Exception ex)
+                {
+                    LogForModel(set, $"Cached local retrieval for {beatmap} failed with {ex}.");
+                }
+
+                return false;
+            }
+
+            [Serializable]
+            [SuppressMessage("ReSharper", "InconsistentNaming")]
+            private class CachedOnlineBeatmapLookup
+            {
+                public int approved { get; set; }
+
+                public int? beatmapset_id { get; set; }
+
+                public int? beatmap_id { get; set; }
+            }
+        }
+    }
+}