PaperMC/nms-patches/InventoryCrafting.patch

--- a/net/minecraft/server/InventoryCrafting.java
+++ b/net/minecraft/server/InventoryCrafting.java
@@ -2,6 +2,14 @@
 
 import java.util.Iterator;
 import javax.annotation.Nullable;
+// CraftBukkit start
+import java.util.List;
+import org.bukkit.Location;
+
+import org.bukkit.craftbukkit.entity.CraftHumanEntity;
+import org.bukkit.entity.HumanEntity;
+import org.bukkit.event.inventory.InventoryType;
+// CraftBukkit end
 
 public class InventoryCrafting implements IInventory, AutoRecipeOutput {
 
@@ -10,6 +18,63 @@
     private final int c;
     public final Container container;
 
+    // CraftBukkit start - add fields
+    public List<HumanEntity> transaction = new java.util.ArrayList<HumanEntity>();
+    private IRecipe currentRecipe;
+    public IInventory resultInventory;
+    private EntityHuman owner;
+    private int maxStack = MAX_STACK;
+
+    public List<ItemStack> getContents() {
+        return this.items;
+    }
+
+    public void onOpen(CraftHumanEntity who) {
+        transaction.add(who);
+    }
+
+    public InventoryType getInvType() {
+        return items.size() == 4 ? InventoryType.CRAFTING : InventoryType.WORKBENCH;
+    }
+
+    public void onClose(CraftHumanEntity who) {
+        transaction.remove(who);
+    }
+
+    public List<HumanEntity> getViewers() {
+        return transaction;
+    }
+
+    public org.bukkit.inventory.InventoryHolder getOwner() {
+        return (owner == null) ? null : owner.getBukkitEntity();
+    }
+
+    public void setMaxStackSize(int size) {
+        maxStack = size;
+        resultInventory.setMaxStackSize(size);
+    }
+
+    @Override
+    public Location getLocation() {
+        return owner.getBukkitEntity().getLocation();
+    }
+
+    @Override
+    public IRecipe getCurrentRecipe() {
+        return currentRecipe;
+    }
+
+    @Override
+    public void setCurrentRecipe(IRecipe currentRecipe) {
+        this.currentRecipe = currentRecipe;
+    }
+
+    public InventoryCrafting(Container container, int i, int j, EntityHuman player) {
+        this(container, i, j);
+        this.owner = player;
+    }
+    // CraftBukkit end
+
     public InventoryCrafting(Container container, int i, int j) {
         this.items = NonNullList.a(i * j, ItemStack.a);
         this.container = container;