Allow items to control the rate of repair from mending (#5102)

patches/minecraft/net/minecraft/entity/item/EntityXPOrb.java.patch

@@ -18,7 +18,7 @@
        if (this.func_180431_b(p_70097_1_)) {
           return false;
        } else {
-@@ -178,6 +180,7 @@
+@@ -178,12 +180,14 @@
     public void func_70100_b_(EntityPlayer p_70100_1_) {
        if (!this.field_70170_p.field_72995_K) {
           if (this.field_70532_c == 0 && p_70100_1_.field_71090_bL == 0) {
@@ -26,3 +26,22 @@
              p_70100_1_.field_71090_bL = 2;
              p_70100_1_.func_71001_a(this, 1);
              ItemStack itemstack = EnchantmentHelper.func_92099_a(Enchantments.field_185296_A, p_70100_1_);
+             if (!itemstack.func_190926_b() && itemstack.func_77951_h()) {
+-               int i = Math.min(this.func_184514_c(this.field_70530_e), itemstack.func_77952_i());
+-               this.field_70530_e -= this.func_184515_b(i);
++               float ratio = itemstack.func_77973_b().getXpRepairRatio(itemstack);
++               int i = Math.min(roundAverage(this.field_70530_e * ratio), itemstack.func_77952_i());
++               this.field_70530_e -= roundAverage(i / ratio);
+                itemstack.func_196085_b(itemstack.func_77952_i() - i);
+             }
+ 
+@@ -261,4 +265,9 @@
+    public boolean func_70075_an() {
+       return false;
+    }
++   
++   private static int roundAverage(float value) {
++      double floor = Math.floor(value);
++      return (int) floor + (Math.random() < value - floor ? 1 : 0);
++   }
+ }

src/main/java/net/minecraftforge/common/extensions/IForgeItem.java

@@ -113,6 +113,15 @@ public interface IForgeItem
      * @return True if reparable
      */
     boolean isRepairable();
+    
+    /**
+    * Determines the amount of durability the mending enchantment
+    * will repair, on average, per point of experience.
+    */
+    default float getXpRepairRatio(ItemStack stack)
+    {
+        return 2f;
+    }
 
     /**
      * Override this method to change the NBT data being sent to the client. You

src/test/java/net/minecraftforge/debug/item/MendingRepairTest.java

@@ -0,0 +1,95 @@
+/*
+ * Minecraft Forge
+ * Copyright (c) 2016-2018.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation version 2.1
+ * of the License.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+package net.minecraftforge.debug.item;
+
+import net.minecraft.client.renderer.block.model.ModelResourceLocation;
+import net.minecraft.creativetab.CreativeTabs;
+import net.minecraft.init.Enchantments;
+import net.minecraft.item.Item;
+import net.minecraft.item.ItemStack;
+import net.minecraft.util.NonNullList;
+import net.minecraftforge.client.event.ModelRegistryEvent;
+import net.minecraftforge.client.model.ModelLoader;
+import net.minecraftforge.event.RegistryEvent;
+import net.minecraftforge.fml.common.Mod;
+import net.minecraftforge.fml.common.eventhandler.SubscribeEvent;
+import net.minecraftforge.fml.common.registry.GameRegistry;
+import net.minecraftforge.fml.relauncher.Side;
+
+@Mod.EventBusSubscriber
+@Mod(modid = MendingRepairTest.MOD_ID, name = "Mending repair amount test mod", version = "1.0")
+public class MendingRepairTest
+{
+    static final boolean ENABLED = true;
+    static final String MOD_ID = "mending_repair_test";
+
+    @GameRegistry.ObjectHolder(MOD_ID + ":test_item")
+    public static final Item TEST_ITEM = null;
+
+    @SubscribeEvent
+    public static void registerItems(RegistryEvent.Register<Item> event)
+    {
+        if (!ENABLED) return;
+        event.getRegistry().register(
+                new TestItem()
+                        .setRegistryName(MOD_ID, "test_item")
+                        .setUnlocalizedName(MOD_ID + ".test_item")
+        );
+    }
+
+    @Mod.EventBusSubscriber(modid = MOD_ID, value = Side.CLIENT)
+    public static final class ClientEventHandler
+    {
+        @SubscribeEvent
+        public static void registerModels(ModelRegistryEvent event)
+        {
+            if (!ENABLED) return;
+            ModelLoader.setCustomModelResourceLocation(TEST_ITEM, 0, new ModelResourceLocation("minecraft:blaze_rod", "inventory"));
+        }
+    }
+
+    private static final class TestItem extends Item
+    {
+        TestItem()
+        {
+            maxStackSize = 1;
+            setMaxDamage(10);
+            setCreativeTab(CreativeTabs.TOOLS);
+        }
+
+        @Override
+        public void getSubItems(CreativeTabs tab, NonNullList<ItemStack> items)
+        {
+            if (this.isInCreativeTab(tab))
+            {
+                ItemStack stack = new ItemStack(this);
+                stack.addEnchantment(Enchantments.MENDING, 1);
+                stack.setItemDamage(stack.getMaxDamage());
+                items.add(stack);
+            }
+        }
+
+        @Override
+        public float getXpRepairRatio(ItemStack stack)
+        {
+            return 0.1f;
+        }
+    }
+}