From 30b3973c9fcef6a8a1a308376815d5559eea3d65 Mon Sep 17 00:00:00 2001
From: Dean Herbert <pe@ppy.sh>
Date: Fri, 24 Jun 2022 18:39:44 +0900
Subject: [PATCH] Difficulty cache invalidation flow

---
 osu.Game/Beatmaps/BeatmapDifficultyCache.cs |  5 +++++
 osu.Game/Beatmaps/BeatmapUpdater.cs         |  2 ++
 osu.Game/Database/MemoryCachingComponent.cs | 10 ++++++++++
 3 files changed, 17 insertions(+)

diff --git a/osu.Game/Beatmaps/BeatmapDifficultyCache.cs b/osu.Game/Beatmaps/BeatmapDifficultyCache.cs
index ef0fa36b16..493de5bef4 100644
--- a/osu.Game/Beatmaps/BeatmapDifficultyCache.cs
+++ b/osu.Game/Beatmaps/BeatmapDifficultyCache.cs
@@ -81,6 +81,11 @@ namespace osu.Game.Beatmaps
             }, true);
         }
 
+        public void Invalidate(IBeatmapInfo beatmap)
+        {
+            base.Invalidate(lookup => lookup.BeatmapInfo.Equals(beatmap));
+        }
+
         /// <summary>
         /// Retrieves a bindable containing the star difficulty of a <see cref="BeatmapInfo"/> that follows the currently-selected ruleset and mods.
         /// </summary>
diff --git a/osu.Game/Beatmaps/BeatmapUpdater.cs b/osu.Game/Beatmaps/BeatmapUpdater.cs
index a24407a734..e6703dd8d0 100644
--- a/osu.Game/Beatmaps/BeatmapUpdater.cs
+++ b/osu.Game/Beatmaps/BeatmapUpdater.cs
@@ -61,6 +61,8 @@ namespace osu.Game.Beatmaps
                 var working = workingBeatmapCache.GetWorkingBeatmap(beatmap);
                 beatmap.Length = calculateLength(working.Beatmap);
                 beatmap.BPM = 60000 / working.Beatmap.GetMostCommonBeatLength();
+
+                difficultyCache.Invalidate(beatmap);
             }
         }
 
diff --git a/osu.Game/Database/MemoryCachingComponent.cs b/osu.Game/Database/MemoryCachingComponent.cs
index 6e6d928dcc..215050460b 100644
--- a/osu.Game/Database/MemoryCachingComponent.cs
+++ b/osu.Game/Database/MemoryCachingComponent.cs
@@ -3,6 +3,7 @@
 
 #nullable disable
 
+using System;
 using System.Collections.Concurrent;
 using System.Threading;
 using System.Threading.Tasks;
@@ -39,6 +40,15 @@ namespace osu.Game.Database
             return computed;
         }
 
+        protected void Invalidate(Func<TLookup, bool> invalidationFunction)
+        {
+            foreach (var kvp in cache)
+            {
+                if (invalidationFunction(kvp.Key))
+                    cache.TryRemove(kvp.Key, out _);
+            }
+        }
+
         protected bool CheckExists([NotNull] TLookup lookup, out TValue value) =>
             cache.TryGetValue(lookup, out value);