PaperMC/Spigot-Server-Patches/0380-Optimize-GameRules-to-use-LinkedHashMap.patch

From 6f90cca3b78f2a8b7699572998b0fbbd1dc76ec5 Mon Sep 17 00:00:00 2001
From: Spottedleaf <Spottedleaf@users.noreply.github.com>
Date: Thu, 4 Apr 2019 17:55:05 -0700
Subject: [PATCH] Optimize GameRules to use LinkedHashMap

Previously TreeMap was used which has poor get(K) performance.

diff --git a/src/main/java/net/minecraft/server/GameRules.java b/src/main/java/net/minecraft/server/GameRules.java
index 3de9d264db..c6a8004745 100644
--- a/src/main/java/net/minecraft/server/GameRules.java
+++ b/src/main/java/net/minecraft/server/GameRules.java
@@ -17,7 +17,17 @@ import javax.annotation.Nullable;
 
 public class GameRules {
 
-    private static final TreeMap<String, GameRules.GameRuleDefinition> a = SystemUtils.a(new TreeMap(), (treemap) -> { // Paper - decompile fix
+    // Paper start - Optimize GameRules
+    private static final int RULES_SIZE = 256;
+
+    private static <K, V> java.util.LinkedHashMap<K, V> linkedMapOf(final int capacity, final TreeMap<K, V> map) {
+        final java.util.LinkedHashMap<K, V> ret = new java.util.LinkedHashMap<>(capacity);
+        ret.putAll(map);
+        return ret;
+    }
+
+    private static final java.util.LinkedHashMap<String, GameRuleDefinition> a = GameRules.linkedMapOf(RULES_SIZE, SystemUtils.a(new TreeMap(), (treemap) -> { // Paper - decompile fix
+        // Paper end
         treemap.put("doFireTick", new GameRules.GameRuleDefinition("true", GameRules.EnumGameRuleType.BOOLEAN_VALUE));
         treemap.put("mobGriefing", new GameRules.GameRuleDefinition("true", GameRules.EnumGameRuleType.BOOLEAN_VALUE));
         treemap.put("keepInventory", new GameRules.GameRuleDefinition("false", GameRules.EnumGameRuleType.BOOLEAN_VALUE));
@@ -51,8 +61,8 @@ public class GameRules {
         treemap.put("doLimitedCrafting", new GameRules.GameRuleDefinition("false", GameRules.EnumGameRuleType.BOOLEAN_VALUE));
         treemap.put("maxCommandChainLength", new GameRules.GameRuleDefinition("65536", GameRules.EnumGameRuleType.NUMERICAL_VALUE));
         treemap.put("announceAdvancements", new GameRules.GameRuleDefinition("true", GameRules.EnumGameRuleType.BOOLEAN_VALUE));
-    });
-    private final TreeMap<String, GameRules.GameRuleValue> b = new TreeMap();
+    })); // Paper - Optimize GameRules
+    private final java.util.LinkedHashMap<String, GameRuleValue> b = new java.util.LinkedHashMap<>(RULES_SIZE); // Paper - Optimize GameRules
 
     public GameRules() {
         Iterator iterator = GameRules.a.entrySet().iterator();
@@ -116,7 +126,7 @@ public class GameRules {
         return (GameRules.GameRuleValue) this.b.get(s);
     }
 
-    public static TreeMap<String, GameRules.GameRuleDefinition> getGameRules() {
+    public static java.util.LinkedHashMap<String, GameRuleDefinition> getGameRules() { // Paper - Optimize GameRules
         return GameRules.a;
     }
 
diff --git a/src/test/java/org/bukkit/GameRuleTest.java b/src/test/java/org/bukkit/GameRuleTest.java
index 1ed0f4cf2b..40edb8d668 100644
--- a/src/test/java/org/bukkit/GameRuleTest.java
+++ b/src/test/java/org/bukkit/GameRuleTest.java
@@ -21,7 +21,7 @@ public class GameRuleTest {
 
     @Test
     public void testMinecraftRules() {
-        TreeMap<String, GameRules.GameRuleDefinition> minecraftRules = GameRules.getGameRules();
+        Map<String, GameRules.GameRuleDefinition> minecraftRules = GameRules.getGameRules(); // Paper - Optimize GameRules
 
         for (Map.Entry<String, GameRules.GameRuleDefinition> entry : minecraftRules.entrySet()) {
             GameRule<?> bukkitRule = GameRule.getByName(entry.getKey());
-- 
2.21.0