Grindstone Events (#8934)

One to modify the output, and one to modify the input.

patches/minecraft/net/minecraft/world/inventory/GrindstoneMenu.java.patch

@@ -1,5 +1,53 @@
 --- a/net/minecraft/world/inventory/GrindstoneMenu.java
 +++ b/net/minecraft/world/inventory/GrindstoneMenu.java
+@@ -34,6 +_,7 @@
+       }
+    };
+    private final ContainerLevelAccess f_39561_;
++   private int xp = -1;
+ 
+    public GrindstoneMenu(int p_39563_, Inventory p_39564_) {
+       this(p_39563_, p_39564_, ContainerLevelAccess.f_39287_);
+@@ -44,12 +_,12 @@
+       this.f_39561_ = p_39568_;
+       this.m_38897_(new Slot(this.f_39560_, 0, 49, 19) {
+          public boolean m_5857_(ItemStack p_39607_) {
+-            return p_39607_.m_41763_() || p_39607_.m_150930_(Items.f_42690_) || p_39607_.m_41793_();
++            return true; //Allow all items in the slot, not just repairable
+          }
+       });
+       this.m_38897_(new Slot(this.f_39560_, 1, 49, 40) {
+          public boolean m_5857_(ItemStack p_39616_) {
+-            return p_39616_.m_41763_() || p_39616_.m_150930_(Items.f_42690_) || p_39616_.m_41793_();
++            return true; //Allow all items in the slot, not just repairable
+          }
+       });
+       this.m_38897_(new Slot(this.f_39559_, 2, 129, 34) {
+@@ -58,6 +_,7 @@
+          }
+ 
+          public void m_142406_(Player p_150574_, ItemStack p_150575_) {
++            if (net.minecraftforge.common.ForgeHooks.onGrindstoneTake(GrindstoneMenu.this.f_39560_, p_39568_, this::m_39631_)) return;
+             p_39568_.m_39292_((p_39634_, p_39635_) -> {
+                if (p_39634_ instanceof ServerLevel) {
+                   ExperienceOrb.m_147082_((ServerLevel)p_39634_, Vec3.m_82512_(p_39635_), this.m_39631_(p_39634_));
+@@ -70,6 +_,7 @@
+          }
+ 
+          private int m_39631_(Level p_39632_) {
++            if (xp > -1) return xp;
+             int l = 0;
+             l += this.m_39636_(GrindstoneMenu.this.f_39560_.m_8020_(0));
+             l += this.m_39636_(GrindstoneMenu.this.f_39560_.m_8020_(1));
+@@ -122,6 +_,8 @@
+       ItemStack itemstack1 = this.f_39560_.m_8020_(1);
+       boolean flag = !itemstack.m_41619_() || !itemstack1.m_41619_();
+       boolean flag1 = !itemstack.m_41619_() && !itemstack1.m_41619_();
++      this.xp = net.minecraftforge.common.ForgeHooks.onGrindstoneChange(itemstack, itemstack1, this.f_39559_, this.xp);
++      if (this.xp != Integer.MIN_VALUE) return;
+       if (!flag) {
+          this.f_39559_.m_6836_(0, ItemStack.f_41583_);
+       } else {
 @@ -143,12 +_,13 @@
              }
  

src/main/java/net/minecraftforge/common/ForgeHooks.java

@@ -9,6 +9,7 @@ import java.net.URI;
 import java.net.URISyntaxException;
 import java.util.*;
 import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.atomic.AtomicInteger;
 import java.util.function.Function;
 import java.util.function.Supplier;
 import java.util.regex.Matcher;
@@ -37,18 +38,29 @@ import net.minecraft.commands.SharedSuggestionProvider;
 import net.minecraft.core.*;
 import net.minecraft.network.chat.*;
 import net.minecraft.network.chat.contents.LiteralContents;
+import net.minecraft.server.level.ServerLevel;
 import net.minecraft.server.packs.PackType;
 import net.minecraft.tags.BlockTags;
 import net.minecraft.tags.TagEntry;
 import net.minecraft.tags.TagKey;
 import net.minecraft.util.datafix.fixes.StructuresBecomeConfiguredFix;
+import net.minecraft.world.Difficulty;
+import net.minecraft.world.InteractionHand;
+import net.minecraft.world.InteractionResult;
 import net.minecraft.world.effect.MobEffect;
+import net.minecraft.world.entity.Entity;
+import net.minecraft.world.entity.EntityType;
+import net.minecraft.world.entity.EquipmentSlot;
+import net.minecraft.world.entity.ExperienceOrb;
+import net.minecraft.world.entity.Mob;
+import net.minecraft.world.entity.MobSpawnType;
+import net.minecraft.world.entity.LivingEntity;
 import net.minecraft.world.entity.ai.attributes.Attribute;
 import net.minecraft.world.entity.ai.attributes.AttributeModifier;
 import net.minecraft.world.entity.ai.attributes.AttributeSupplier;
 import net.minecraft.world.entity.ai.attributes.DefaultAttributes;
-import net.minecraft.world.entity.EquipmentSlot;
 import net.minecraft.world.entity.monster.EnderMan;
+import net.minecraft.world.inventory.ContainerLevelAccess;
 import net.minecraft.world.item.*;
 import net.minecraft.world.item.crafting.Ingredient;
 import net.minecraft.world.item.crafting.RecipeType;
@@ -65,11 +77,6 @@ import net.minecraft.world.level.block.state.BlockState;
 import net.minecraft.client.Minecraft;
 import net.minecraft.client.gui.screens.Screen;
 import net.minecraft.world.item.enchantment.EnchantmentHelper;
-import net.minecraft.world.entity.Entity;
-import net.minecraft.world.entity.EntityType;
-import net.minecraft.world.entity.Mob;
-import net.minecraft.world.entity.MobSpawnType;
-import net.minecraft.world.entity.LivingEntity;
 import net.minecraft.world.entity.item.ItemEntity;
 import net.minecraft.world.entity.player.Player;
 import net.minecraft.server.level.ServerPlayer;
@@ -86,7 +93,6 @@ import net.minecraft.world.item.alchemy.Potion;
 import net.minecraft.world.item.alchemy.PotionUtils;
 import net.minecraft.stats.Stats;
 import net.minecraft.world.phys.Vec3;
-import net.minecraft.world.*;
 import net.minecraft.world.level.BaseSpawner;
 import net.minecraft.world.level.block.entity.FurnaceBlockEntity;
 import net.minecraft.world.level.block.entity.BlockEntity;
@@ -107,6 +113,7 @@ import net.minecraftforge.common.util.MavenVersionStringHelper;
 import net.minecraftforge.event.AnvilUpdateEvent;
 import net.minecraftforge.event.DifficultyChangeEvent;
 import net.minecraftforge.event.ForgeEventFactory;
+import net.minecraftforge.event.GrindstoneEvent;
 import net.minecraftforge.event.ItemAttributeModifierEvent;
 import net.minecraftforge.event.ModMismatchEvent;
 import net.minecraftforge.event.ServerChatEvent;
@@ -734,6 +741,37 @@ public class ForgeHooks
         return e.getBreakChance();
     }
 
+    public static int onGrindstoneChange(@NotNull ItemStack top, @NotNull ItemStack bottom, Container outputSlot, int xp)
+    {
+        GrindstoneEvent.OnplaceItem e = new GrindstoneEvent.OnplaceItem(top, bottom, xp);
+        if (MinecraftForge.EVENT_BUS.post(e)) return e.getXp();
+        if (e.getOutput().isEmpty()) return Integer.MIN_VALUE;
+
+        outputSlot.setItem(0, e.getOutput());
+        return e.getXp();
+    }
+
+    public static boolean onGrindstoneTake(Container inputSlots, ContainerLevelAccess access, Function<Level, Integer> xpFunction)
+    {
+        access.execute((l,p) -> {
+            int xp = xpFunction.apply(l);
+            GrindstoneEvent.OnTakeItem e = new GrindstoneEvent.OnTakeItem(inputSlots.getItem(0), inputSlots.getItem(1), xp);
+            if (MinecraftForge.EVENT_BUS.post(e))
+            {
+                return;
+            }
+            if (l instanceof ServerLevel)
+            {
+                ExperienceOrb.award((ServerLevel)l, Vec3.atCenterOf(p), e.getXp());
+            }
+            l.levelEvent(1042, p, 0);
+            inputSlots.setItem(0, e.getNewTopItem());
+            inputSlots.setItem(1, e.getNewBottomItem());
+            inputSlots.setChanged();
+        });
+        return true;
+    }
+
     private static ThreadLocal<Player> craftingPlayer = new ThreadLocal<Player>();
     public static void setCraftingPlayer(Player player)
     {

src/main/java/net/minecraftforge/event/GrindstoneEvent.java

@@ -0,0 +1,167 @@
+/*
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+
+package net.minecraftforge.event;
+
+import net.minecraft.world.entity.player.Inventory;
+import net.minecraft.world.inventory.GrindstoneMenu;
+import net.minecraft.world.item.ItemStack;
+import net.minecraftforge.eventbus.api.Cancelable;
+import net.minecraftforge.eventbus.api.Event;
+
+public abstract class GrindstoneEvent extends Event
+{
+    private final ItemStack top;
+    private final ItemStack bottom;
+    private int xp;
+
+    protected GrindstoneEvent(ItemStack top, ItemStack bottom, int xp)
+    {
+        this.top = top;
+        this.bottom = bottom;
+        this.xp = xp;
+    }
+
+    /**
+     * @return The item in the top input grindstone slot. <br>
+     */
+    public ItemStack getTopItem()
+    {
+        return top;
+    }
+
+    /**
+     * @return The item in the bottom input grindstone slot. <br>
+     */
+    public ItemStack getBottomItem()
+    {
+        return bottom;
+    }
+
+    /**
+     * This is the experience amount determined by the event, not the vanilla behavior. <br>
+     * If you are the first receiver of this event, it is guaranteed to be -1. <br>
+     * The value must be set to a positive value to override vanilla behavior. <br>
+     * if the value is equal to -1, the vanilla behavior for calculating experience will run. <br>
+     * @return The experience amount given to the player. <br>
+     */
+    public int getXp()
+    {
+        return xp;
+    }
+
+    /**
+     * Sets the experience amount. <br>
+     * @param xp The experience amount given to the player. <br>
+     */
+    public void setXp(int xp)
+    {
+        this.xp = xp;
+    }
+
+    /**
+     * This event is {@link Cancelable} <br>
+     * {@link OnplaceItem} is fired when the inputs to a grindstone are changed. <br>
+     * It is called from {@link GrindstoneMenu#createResult()}. <br>
+     * If the event is canceled, vanilla behavior will not run, and the output will be set to {@link ItemStack#EMPTY}. <br>
+     * If the event is not canceled, but the output is not empty, it will set the output and not run vanilla behavior. <br>
+     * if the output is empty, and the event is not canceled, vanilla behavior will execute. <br>
+     * if the amount of experience is larger than or equal 0, the vanilla behavior for calculating experience will not run. <br>
+     */
+    @Cancelable
+    public static class OnplaceItem extends GrindstoneEvent
+    {
+        private ItemStack output;
+
+        public OnplaceItem(ItemStack top, ItemStack bottom, int xp)
+        {
+            super(top, bottom, xp);
+            this.output = ItemStack.EMPTY;
+        }
+
+        /**
+         * This is the output as determined by the event, not by the vanilla behavior between these two items. <br>
+         * If you are the first receiver of this event, it is guaranteed to be empty. <br>
+         * It will only be non-empty if changed by an event handler. <br>
+         * If this event is cancelled, this output stack is discarded. <br>
+         * @return The item to set in the output grindstone slot. <br>
+         */
+        public ItemStack getOutput()
+        {
+            return output;
+        }
+
+        /**
+         * Sets the output slot to a specific itemstack.
+         * @param output The stack to change the output to.
+         */
+        public void setOutput(ItemStack output)
+        {
+            this.output = output;
+        }
+    }
+
+    /**
+     * This event is {@link Cancelable} <br>
+     * {@link OnTakeItem} is fired when the output in a grindstone are is taken. <br>
+     * It is called from {@link GrindstoneMenu#GrindstoneMenu(int, Inventory)}. <br>
+     * If the event is canceled, vanilla behavior will not run, and no inputs will be consumed. <br>
+     * if the amount of experience is larger than or equal 0, the vanilla behavior for calculating experience will not run. <br>
+     */
+    @Cancelable
+    public static class OnTakeItem extends GrindstoneEvent
+    {
+        private ItemStack newTop = ItemStack.EMPTY;
+        private ItemStack newBottom = ItemStack.EMPTY;
+
+        public OnTakeItem(ItemStack top, ItemStack bottom, int xp)
+        {
+            super(top, bottom, xp);
+        }
+
+        /**
+         * @return The item in that will be in the top input grindstone slot after the event. <br>
+         */
+        public ItemStack getNewTopItem()
+        {
+            return newTop;
+        }
+
+        /**
+         * @return The item in that will be in the bottom input grindstone slot after the event. <br>
+         */
+        public ItemStack getNewBottomItem()
+        {
+            return newBottom;
+        }
+
+        /**
+         * Sets the itemstack in the top slot. <br>
+         * @param newTop
+         */
+        public void setNewTopItem(ItemStack newTop)
+        {
+            this.newTop = newTop;
+        }
+
+        /**
+         * Sets the itemstack in the bottom slot. <br>
+         * @param newBottom
+         */
+        public void setNewBottomItem(ItemStack newBottom)
+        {
+            this.newBottom = newBottom;
+        }
+
+        /**
+         * This is the experience amount that will be returned by the event. <br>
+         * @return The experience amount given to the player. <br>
+         */
+        public int getXp()
+        {
+            return super.getXp();
+        }
+    }
+}