From 48287459a0aa6136e711eb7bc07df187338a7876 Mon Sep 17 00:00:00 2001
From: Dean Herbert <pe@ppy.sh>
Date: Thu, 5 Dec 2019 01:52:22 +0900
Subject: [PATCH] Optimise filters to avoid property retrieval

Also reduces number of instantiations of SearchableTerms array in the case of multiple criteria terms.
---
 .../Select/Carousel/CarouselBeatmap.cs        | 32 ++++++++++---------
 osu.Game/Screens/Select/FilterCriteria.cs     |  6 +++-
 2 files changed, 22 insertions(+), 16 deletions(-)

diff --git a/osu.Game/Screens/Select/Carousel/CarouselBeatmap.cs b/osu.Game/Screens/Select/Carousel/CarouselBeatmap.cs
index afd6211dec..68a6ad8845 100644
--- a/osu.Game/Screens/Select/Carousel/CarouselBeatmap.cs
+++ b/osu.Game/Screens/Select/Carousel/CarouselBeatmap.cs
@@ -2,6 +2,7 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using System;
+using System.Collections.Generic;
 using System.Linq;
 using osu.Game.Beatmaps;
 using osu.Game.Screens.Select.Filter;
@@ -29,28 +30,29 @@ public override void Filter(FilterCriteria criteria)
                 Beatmap.RulesetID == criteria.Ruleset.ID ||
                 (Beatmap.RulesetID == 0 && criteria.Ruleset.ID > 0 && criteria.AllowConvertedBeatmaps);
 
-            match &= criteria.StarDifficulty.IsInRange(Beatmap.StarDifficulty);
-            match &= criteria.ApproachRate.IsInRange(Beatmap.BaseDifficulty.ApproachRate);
-            match &= criteria.DrainRate.IsInRange(Beatmap.BaseDifficulty.DrainRate);
-            match &= criteria.CircleSize.IsInRange(Beatmap.BaseDifficulty.CircleSize);
-            match &= criteria.Length.IsInRange(Beatmap.Length);
-            match &= criteria.BPM.IsInRange(Beatmap.BPM);
+            match &= !criteria.StarDifficulty.HasFilter || criteria.StarDifficulty.IsInRange(Beatmap.StarDifficulty);
+            match &= !criteria.ApproachRate.HasFilter || criteria.ApproachRate.IsInRange(Beatmap.BaseDifficulty.ApproachRate);
+            match &= !criteria.DrainRate.HasFilter || criteria.DrainRate.IsInRange(Beatmap.BaseDifficulty.DrainRate);
+            match &= !criteria.CircleSize.HasFilter || criteria.CircleSize.IsInRange(Beatmap.BaseDifficulty.CircleSize);
+            match &= !criteria.Length.HasFilter || criteria.Length.IsInRange(Beatmap.Length);
+            match &= !criteria.BPM.HasFilter || criteria.BPM.IsInRange(Beatmap.BPM);
 
-            match &= criteria.BeatDivisor.IsInRange(Beatmap.BeatDivisor);
-            match &= criteria.OnlineStatus.IsInRange(Beatmap.Status);
+            match &= !criteria.BeatDivisor.HasFilter || criteria.BeatDivisor.IsInRange(Beatmap.BeatDivisor);
+            match &= !criteria.OnlineStatus.HasFilter || criteria.OnlineStatus.IsInRange(Beatmap.Status);
 
-            match &= criteria.Creator.Matches(Beatmap.Metadata.AuthorString);
-            match &= criteria.Artist.Matches(Beatmap.Metadata.Artist) ||
+            match &= !criteria.Creator.HasFilter || criteria.Creator.Matches(Beatmap.Metadata.AuthorString);
+            match &= !criteria.Artist.HasFilter || criteria.Artist.Matches(Beatmap.Metadata.Artist) ||
                      criteria.Artist.Matches(Beatmap.Metadata.ArtistUnicode);
 
             if (match)
             {
+                var terms = new List<string>();
+
+                terms.AddRange(Beatmap.Metadata.SearchableTerms);
+                terms.Add(Beatmap.Version);
+
                 foreach (var criteriaTerm in criteria.SearchTerms)
-                {
-                    match &=
-                        Beatmap.Metadata.SearchableTerms.Any(term => term.IndexOf(criteriaTerm, StringComparison.InvariantCultureIgnoreCase) >= 0) ||
-                        Beatmap.Version.IndexOf(criteriaTerm, StringComparison.InvariantCultureIgnoreCase) >= 0;
-                }
+                    match &= terms.Any(term => term.IndexOf(criteriaTerm, StringComparison.InvariantCultureIgnoreCase) >= 0);
             }
 
             Filtered.Value = !match;
diff --git a/osu.Game/Screens/Select/FilterCriteria.cs b/osu.Game/Screens/Select/FilterCriteria.cs
index 7971506fa3..abcb1f2171 100644
--- a/osu.Game/Screens/Select/FilterCriteria.cs
+++ b/osu.Game/Screens/Select/FilterCriteria.cs
@@ -46,6 +46,8 @@ public string SearchText
         public struct OptionalRange<T> : IEquatable<OptionalRange<T>>
             where T : struct, IComparable
         {
+            public bool HasFilter => Max != null || Min != null;
+
             public bool IsInRange(T value)
             {
                 if (Min != null)
@@ -87,9 +89,11 @@ public bool Equals(OptionalRange<T> other)
 
         public struct OptionalTextFilter : IEquatable<OptionalTextFilter>
         {
+            public bool HasFilter => !string.IsNullOrEmpty(SearchTerm);
+
             public bool Matches(string value)
             {
-                if (string.IsNullOrEmpty(SearchTerm))
+                if (!HasFilter)
                     return true;
 
                 // search term is guaranteed to be non-empty, so if the string we're comparing is empty, it's not matching