Paper/patches/server/0839-Use-array-for-gamerule-storage.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Paul Sauve <paul@technove.co>
Date: Sun, 9 May 2021 16:49:49 -0500
Subject: [PATCH] Use array for gamerule storage


diff --git a/src/main/java/net/minecraft/world/level/GameRules.java b/src/main/java/net/minecraft/world/level/GameRules.java
index 51e560d7856f230c5aa2dc32706c3a4996720aa5..89e327bc3a45879fe68887c7aadb077f31a770eb 100644
--- a/src/main/java/net/minecraft/world/level/GameRules.java
+++ b/src/main/java/net/minecraft/world/level/GameRules.java
@@ -122,6 +122,7 @@ public class GameRules {
         worldserver.setDefaultSpawnPos(worldserver.getSharedSpawnPos(), worldserver.getSharedSpawnAngle());
     }));
     private final Map<GameRules.Key<?>, GameRules.Value<?>> rules;
+    private final GameRules.Value<?>[] gameruleArray; // Paper - Perf: Use array for gamerule storage
 
     private static <T extends GameRules.Value<T>> GameRules.Key<T> register(String name, GameRules.Category category, GameRules.Type<T> type) {
         GameRules.Key<T> gamerules_gamerulekey = new GameRules.Key<>(name, category);
@@ -140,17 +141,30 @@ public class GameRules {
     }
 
     public GameRules() {
-        this.rules = (Map) GameRules.GAME_RULE_TYPES.entrySet().stream().collect(ImmutableMap.toImmutableMap(Entry::getKey, (entry) -> {
+        // Paper start - Perf: Use array for gamerule storage
+        this((Map) GameRules.GAME_RULE_TYPES.entrySet().stream().collect(ImmutableMap.toImmutableMap(Entry::getKey, (entry) -> {
             return ((GameRules.Type) entry.getValue()).createRule();
-        }));
+        })));
+        // Paper end - Perf: Use array for gamerule storage
     }
 
     private GameRules(Map<GameRules.Key<?>, GameRules.Value<?>> rules) {
         this.rules = rules;
+
+        // Paper start - Perf: Use array for gamerule storage
+        int arraySize = rules.keySet().stream().mapToInt(key -> key.gameRuleIndex).max().orElse(-1) + 1;
+        GameRules.Value<?>[] values = new GameRules.Value[arraySize];
+
+        for (Entry<GameRules.Key<?>, GameRules.Value<?>> entry : rules.entrySet()) {
+            values[entry.getKey().gameRuleIndex] = entry.getValue();
+        }
+
+        this.gameruleArray = values;
+        // Paper end - Perf: Use array for gamerule storage
     }
 
     public <T extends GameRules.Value<T>> T getRule(GameRules.Key<T> key) {
-        return (T) this.rules.get(key); // CraftBukkit - decompile error
+        return key == null ? null : (T) this.gameruleArray[key.gameRuleIndex]; // Paper - Perf: Use array for gamerule storage
     }
 
     public CompoundTag createTag() {
@@ -209,6 +223,10 @@ public class GameRules {
     }
 
     public static final class Key<T extends GameRules.Value<T>> {
+        // Paper start - Perf: Use array for gamerule storage
+        private static int lastGameRuleIndex = 0;
+        public final int gameRuleIndex = lastGameRuleIndex++;
+        // Paper end - Perf: Use array for gamerule storage
 
         final String id;
         private final GameRules.Category category;