From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Mykyta Komarn <nkomarn@hotmail.com>
Date: Thu, 1 Oct 2020 06:57:43 -0700
Subject: [PATCH] Heavily optimize recipe lookups in CraftingManager

Recipe lookups are now cached in CraftingManager, which prevent unnecessary ArrayLists being created for every lookup. Additionally, an EMPTY_MAP variable was added to prevent bottlenecks during map creation, since that map is only ever iterated.

GlueList was also used as a replacement for ArrayList as it is substantially faster.

These changes knock off an extra ~10ms of tick duration with a sample of ~7,700 running furnaces on a server.

diff --git a/src/main/java/net/minecraft/server/CraftingManager.java b/src/main/java/net/minecraft/server/CraftingManager.java
index 09b8065156a66a72ad5d09c6e8be0551970ffb56..bd4bc17245d32772aef60e53eae4a572ffc6d1c2 100644
--- a/src/main/java/net/minecraft/server/CraftingManager.java
+++ b/src/main/java/net/minecraft/server/CraftingManager.java
@@ -25,6 +25,10 @@ public class CraftingManager extends ResourceDataJson {
     private static final Logger LOGGER = LogManager.getLogger();
     public Map<Recipes<?>, Object2ObjectLinkedOpenHashMap<MinecraftKey, IRecipe<?>>> recipes = ImmutableMap.of(); // CraftBukkit
     private boolean d;
+    // Yatopia start
+    public static final Object2ObjectLinkedOpenHashMap<MinecraftKey, IRecipe<?>> EMPTY_MAP = new Object2ObjectLinkedOpenHashMap<>();
+    public static final Map<Recipes<?>, List<IRecipe<?>>> CACHE = new Object2ObjectLinkedOpenHashMap<>();
+    // Yatopia end
 
     public CraftingManager() {
         super(CraftingManager.a, "recipes");
@@ -108,12 +112,18 @@ public class CraftingManager extends ResourceDataJson {
     }
 
     public <C extends IInventory, T extends IRecipe<C>> List<T> a(Recipes<T> recipes) {
+        // Yatopia start - replaced Logic
+        return (List) CACHE.computeIfAbsent(recipes, recipes1 -> {
+            return new net.yatopia.server.list.GlueList<>(this.b(recipes).values());
+        });
+        /*
         List<IRecipe<C>> list = new ArrayList<>();
         for (IRecipe<C> irecipe : this.b(recipes).values()) {
             IRecipe<C> ciRecipe = irecipe;
             list.add(ciRecipe);
         }
         return (List) list;
+        */ // Yatopia end
     }
 
     public <C extends IInventory, T extends IRecipe<C>> List<T> b(Recipes<T> recipes, C c0, World world) {
@@ -134,7 +144,7 @@ public class CraftingManager extends ResourceDataJson {
     }
 
     private <C extends IInventory, T extends IRecipe<C>> Map<MinecraftKey, IRecipe<C>> b(Recipes<T> recipes) {
-        return (Map) this.recipes.getOrDefault(recipes, new Object2ObjectLinkedOpenHashMap<>()); // CraftBukkit
+        return (Map) this.recipes.getOrDefault(recipes, EMPTY_MAP); // CraftBukkit // Yatopia
     }
 
     public <C extends IInventory, T extends IRecipe<C>> NonNullList<ItemStack> c(Recipes<T> recipes, C c0, World world) {
diff --git a/src/main/java/net/minecraft/server/RecipeItemStack.java b/src/main/java/net/minecraft/server/RecipeItemStack.java
index 30da7471c3ecc66a61cb9fe1dd58d6d65438c505..27978f7b52c8db02f69fdcb092ffcce4550904d3 100644
--- a/src/main/java/net/minecraft/server/RecipeItemStack.java
+++ b/src/main/java/net/minecraft/server/RecipeItemStack.java
@@ -32,7 +32,7 @@ public final class RecipeItemStack implements Predicate<ItemStack> {
 
     public void buildChoices() {
         if (this.choices == null) {
-            List<ItemStack> list = new ArrayList<>();
+            List<ItemStack> list = new net.yatopia.server.list.GlueList<>(); // Yatopia
             Set<ItemStack> uniqueValues = new HashSet<>();
             for (Provider recipeitemstack_provider : this.b) {
                 for (ItemStack itemStack : recipeitemstack_provider.a()) {