PaperMC/patches/server/1021-Improve-performance-of-mass-crafts.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Jake Potrebic <jake.m.potrebic@gmail.com>
Date: Sun, 13 Aug 2023 15:41:52 -0700
Subject: [PATCH] Improve performance of mass crafts

When the server crafts all available items in CraftingMenu or InventoryMenu the game
checks either 4 or 9 times for each individual craft for a matching recipe for that container.
This check can be expensive if 64 total crafts are being performed with the recipe matching logic
being run 64 * 9 + 64 times. A breakdown of those times is below. This patch caches the last matching
recipe so that it is checked first and only if it doesn't match does the rest of the matching logic run.

Shift-click crafts are processed one at a time, so shift clicking on an item in the result of a iron block craft
where all the 9 inputs are full stacks of iron will run 64 iron block crafts. For each of those crafts, the
'remaining' blocks are calculated. This is due to recipes that have leftover items like buckets. This is done
for each craft, and done once to get the full 9 leftover items which are usually air. Then 1 item is removed
from each of the 9 inputs and each time that happens, logic is triggered to update the result itemstack. So
for each craft, that logic is run 9 times (hence the 64 * 9). The + 64 is from the 64 checks for remaining items.

After this patch, the full iteration over all recipes checking for a match should run once for a full craft to find the
initial recipe match. Then that recipe will be checked first for all future recipe match checks.

diff --git a/src/main/java/net/minecraft/world/inventory/CraftingMenu.java b/src/main/java/net/minecraft/world/inventory/CraftingMenu.java
index 389b8cf74066f9cec90b54d86f5ff7661964b585..948afb5b10d3b515f21810524bd72da2d963f808 100644
--- a/src/main/java/net/minecraft/world/inventory/CraftingMenu.java
+++ b/src/main/java/net/minecraft/world/inventory/CraftingMenu.java
@@ -75,7 +75,8 @@ public class CraftingMenu extends RecipeBookMenu<CraftingContainer> {
         if (!world.isClientSide) {
             ServerPlayer entityplayer = (ServerPlayer) player;
             ItemStack itemstack = ItemStack.EMPTY;
-            Optional<CraftingRecipe> optional = world.getServer().getRecipeManager().getRecipeFor(RecipeType.CRAFTING, craftingInventory, world);
+            final Recipe<?> currentRecipe = craftingInventory.getCurrentRecipe(); // Paper - check last recipe used first
+            Optional<CraftingRecipe> optional = currentRecipe == null ? world.getServer().getRecipeManager().getRecipeFor(RecipeType.CRAFTING, craftingInventory, world) : world.getServer().getRecipeManager().getRecipeFor(RecipeType.CRAFTING, craftingInventory, world, currentRecipe.getId()).map(com.mojang.datafixers.util.Pair::getSecond); // Paper - check last recipe used first
 
             if (optional.isPresent()) {
                 CraftingRecipe recipecrafting = (CraftingRecipe) optional.get();
diff --git a/src/main/java/net/minecraft/world/inventory/ResultSlot.java b/src/main/java/net/minecraft/world/inventory/ResultSlot.java
index ddf87ef1979c4ae4f14cd6aa220f9146d5e20909..46d1f768e4dcc2942ee7af81ee2713df10251731 100644
--- a/src/main/java/net/minecraft/world/inventory/ResultSlot.java
+++ b/src/main/java/net/minecraft/world/inventory/ResultSlot.java
@@ -59,7 +59,7 @@ public class ResultSlot extends Slot {
     @Override
     public void onTake(Player player, ItemStack stack) {
         this.checkTakeAchievements(stack);
-        NonNullList<ItemStack> nonNullList = player.level().getRecipeManager().getRemainingItemsFor(RecipeType.CRAFTING, this.craftSlots, player.level());
+        NonNullList<ItemStack> nonNullList = player.level().getRecipeManager().getRemainingItemsFor(RecipeType.CRAFTING, this.craftSlots, player.level(), this.craftSlots.getCurrentRecipe() != null ? this.craftSlots.getCurrentRecipe().getId() : null); // Paper - check last recipe used first
 
         for(int i = 0; i < nonNullList.size(); ++i) {
             ItemStack itemStack = this.craftSlots.getItem(i);
diff --git a/src/main/java/net/minecraft/world/item/crafting/RecipeManager.java b/src/main/java/net/minecraft/world/item/crafting/RecipeManager.java
index ab6dc3449a1d3b7acf1d7bf5ac1c24224cc252c7..9ffb6999171f602f0b113dac40e0130410cad870 100644
--- a/src/main/java/net/minecraft/world/item/crafting/RecipeManager.java
+++ b/src/main/java/net/minecraft/world/item/crafting/RecipeManager.java
@@ -119,13 +119,16 @@ public class RecipeManager extends SimpleJsonResourceReloadListener {
             T t0 = map.get(id); // CraftBukkit - decompile error
 
             if (t0 != null && t0.matches(inventory, world)) {
+                inventory.setCurrentRecipe(t0); // Paper
                 return Optional.of(Pair.of(id, t0));
             }
         }
 
+        inventory.setCurrentRecipe(null); // Paper - clear before it might be set again
         return map.entrySet().stream().filter((entry) -> {
             return ((Recipe) entry.getValue()).matches(inventory, world);
         }).findFirst().map((entry) -> {
+            inventory.setCurrentRecipe(entry.getValue()); // Paper
             return Pair.of((ResourceLocation) entry.getKey(), entry.getValue()); // CraftBukkit - decompile error
         });
     }
@@ -147,7 +150,12 @@ public class RecipeManager extends SimpleJsonResourceReloadListener {
     }
 
     public <C extends Container, T extends Recipe<C>> NonNullList<ItemStack> getRemainingItemsFor(RecipeType<T> type, C inventory, Level world) {
-        Optional<T> optional = this.getRecipeFor(type, inventory, world);
+        // Paper start - check last recipe used first
+        return this.getRemainingItemsFor(type, inventory, world, null);
+    }
+    public <C extends Container, T extends Recipe<C>> NonNullList<ItemStack> getRemainingItemsFor(RecipeType<T> type, C inventory, Level world, @Nullable ResourceLocation firstToCheck) {
+        Optional<T> optional = firstToCheck == null ? this.getRecipeFor(type, inventory, world) : this.getRecipeFor(type, inventory, world, firstToCheck).map(Pair::getSecond);
+        // Paper end
 
         if (optional.isPresent()) {
             return ((Recipe) optional.get()).getRemainingItems(inventory);