From 61260cf599f07cbaaeaa7a2e03c744b8dcd8e5cf Mon Sep 17 00:00:00 2001
From: naoey <naoey@protonmail.ch>
Date: Thu, 27 Jun 2019 15:14:57 +0530
Subject: [PATCH] Hand off comparison logic for database query to implementors

Equals overrides are not used in EF queries without running the comaprison locally instead of on the database, so to preserve that the comparison logic is instead implemented on a per manager basis.
---
 osu.Game/Beatmaps/BeatmapManager.cs                  |  2 ++
 osu.Game/Database/DownloadableArchiveModelManager.cs | 10 +++++++++-
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/osu.Game/Beatmaps/BeatmapManager.cs b/osu.Game/Beatmaps/BeatmapManager.cs
index d5b19485de..fe8fef3e07 100644
--- a/osu.Game/Beatmaps/BeatmapManager.cs
+++ b/osu.Game/Beatmaps/BeatmapManager.cs
@@ -145,6 +145,8 @@ namespace osu.Game.Beatmaps
             void resetIds() => beatmapSet.Beatmaps.ForEach(b => b.OnlineBeatmapID = null);
         }
 
+        protected override bool CheckLocalAvailability(BeatmapSetInfo model, IQueryable<BeatmapSetInfo> items) => items.Any(b => b.OnlineBeatmapSetID == model.OnlineBeatmapSetID);
+
         /// <summary>
         /// Delete a beatmap difficulty.
         /// </summary>
diff --git a/osu.Game/Database/DownloadableArchiveModelManager.cs b/osu.Game/Database/DownloadableArchiveModelManager.cs
index 2e7d70c941..78c0837ce9 100644
--- a/osu.Game/Database/DownloadableArchiveModelManager.cs
+++ b/osu.Game/Database/DownloadableArchiveModelManager.cs
@@ -110,7 +110,15 @@ namespace osu.Game.Database
             return true;
         }
 
-        public virtual bool IsAvailableLocally(TModel model) => modelStore.ConsumableItems.Any(m => m.Equals(model) && !m.DeletePending);
+        public bool IsAvailableLocally(TModel model) => CheckLocalAvailability(model, modelStore.ConsumableItems.Where(m => !m.DeletePending));
+
+        /// <summary>
+        /// Performs implementation specific comparisons to determine whether a given model is present in the local store.
+        /// </summary>
+        /// <param name="model">The <see cref="TModel"/> whose existence needs to be checked.</param>
+        /// <param name="items">The usable items present in the store.</param>
+        /// <returns>Whether the <see cref="TModel"/> exists.</returns>
+        protected abstract bool CheckLocalAvailability(TModel model, IQueryable<TModel> items);
 
         public ArchiveDownloadRequest<TModel> GetExistingDownload(TModel model) => currentDownloads.Find(r => r.Model.Equals(model));