PaperMC/nms-patches/TileEntityFurnace.patch

--- a/net/minecraft/server/TileEntityFurnace.java
+++ b/net/minecraft/server/TileEntityFurnace.java
@@ -1,6 +1,15 @@
 package net.minecraft.server;
 
 import javax.annotation.Nullable;
+// CraftBukkit start
+import java.util.List;
+
+import org.bukkit.craftbukkit.inventory.CraftItemStack;
+import org.bukkit.entity.HumanEntity;
+import org.bukkit.event.inventory.FurnaceBurnEvent;
+import org.bukkit.event.inventory.FurnaceSmeltEvent;
+import org.bukkit.craftbukkit.entity.CraftHumanEntity;
+// CraftBukkit end
 
 public class TileEntityFurnace extends TileEntityContainer implements ITickable, IWorldInventory {
 
@@ -14,6 +23,32 @@
     private int cookTimeTotal;
     private String m;
 
+    // CraftBukkit start - add fields and methods
+    private int lastTick = MinecraftServer.currentTick;
+    private int maxStack = MAX_STACK;
+    public List<HumanEntity> transaction = new java.util.ArrayList<HumanEntity>();
+
+    public ItemStack[] getContents() {
+        return this.items;
+    }
+
+    public void onOpen(CraftHumanEntity who) {
+        transaction.add(who);
+    }
+
+    public void onClose(CraftHumanEntity who) {
+        transaction.remove(who);
+    }
+
+    public List<HumanEntity> getViewers() {
+        return transaction;
+    }
+
+    public void setMaxStackSize(int size) {
+        maxStack = size;
+    }
+    // CraftBukkit end
+
     public TileEntityFurnace() {}
 
     public int getSize() {
@@ -126,11 +161,29 @@
     }
 
     public void E_() {
-        boolean flag = this.isBurning();
+        boolean flag = (this.getBlock() == Blocks.LIT_FURNACE); // CraftBukkit - SPIGOT-844 - Check if furnace block is lit using the block instead of burn time
         boolean flag1 = false;
 
+        // CraftBukkit start - Use wall time instead of ticks for cooking
+        int elapsedTicks = MinecraftServer.currentTick - this.lastTick;
+        this.lastTick = MinecraftServer.currentTick;
+
+        // CraftBukkit - moved from below
+        if (this.isBurning() && this.canBurn()) {
+            this.cookTime += elapsedTicks;
+            if (this.cookTime >= this.cookTimeTotal) {
+                this.cookTime = 0;
+                this.cookTimeTotal = this.a(this.items[0]);
+                this.burn();
+                flag1 = true;
+            }
+        } else {
+            this.cookTime = 0;
+        }
+        // CraftBukkit end
+
         if (this.isBurning()) {
-            --this.burnTime;
+            this.burnTime -= elapsedTicks; // CraftBukkit - use elapsedTicks in place of constant
         }
 
         if (!this.world.isClientSide) {
@@ -139,10 +192,21 @@
                     this.cookTime = MathHelper.clamp(this.cookTime - 2, 0, this.cookTimeTotal);
                 }
             } else {
-                if (!this.isBurning() && this.canBurn()) {
-                    this.burnTime = fuelTime(this.items[1]);
-                    this.ticksForCurrentFuel = this.burnTime;
-                    if (this.isBurning()) {
+                // CraftBukkit start - Handle multiple elapsed ticks
+                if (this.burnTime <= 0 && this.canBurn()) { // CraftBukkit - == to <=
+                    CraftItemStack fuel = CraftItemStack.asCraftMirror(this.items[1]);
+
+                    FurnaceBurnEvent furnaceBurnEvent = new FurnaceBurnEvent(this.world.getWorld().getBlockAt(position.getX(), position.getY(), position.getZ()), fuel, fuelTime(this.items[1]));
+                    this.world.getServer().getPluginManager().callEvent(furnaceBurnEvent);
+
+                    if (furnaceBurnEvent.isCancelled()) {
+                        return;
+                    }
+
+                    this.ticksForCurrentFuel = furnaceBurnEvent.getBurnTime();
+                    this.burnTime += this.ticksForCurrentFuel;
+                    if (this.burnTime > 0 && furnaceBurnEvent.isBurning()) {
+                        // CraftBukkit end
                         flag1 = true;
                         if (this.items[1] != null) {
                             --this.items[1].count;
@@ -155,6 +219,7 @@
                     }
                 }
 
+                /* CraftBukkit start - Moved up
                 if (this.isBurning() && this.canBurn()) {
                     ++this.cookTime;
                     if (this.cookTime == this.cookTimeTotal) {
@@ -166,11 +231,13 @@
                 } else {
                     this.cookTime = 0;
                 }
+                */
             }
 
             if (flag != this.isBurning()) {
                 flag1 = true;
                 BlockFurnace.a(this.isBurning(), this.world, this.position);
+                this.invalidateBlockCache(); // CraftBukkit - Invalidate tile entity's cached block type 
             }
         }
 
@@ -190,7 +257,8 @@
         } else {
             ItemStack itemstack = RecipesFurnace.getInstance().getResult(this.items[0]);
 
-            return itemstack == null ? false : (this.items[2] == null ? true : (!this.items[2].doMaterialsMatch(itemstack) ? false : (this.items[2].count < this.getMaxStackSize() && this.items[2].count < this.items[2].getMaxStackSize() ? true : this.items[2].count < itemstack.getMaxStackSize())));
+            // CraftBukkit - consider resultant count instead of current count
+            return itemstack == null ? false : (this.items[2] == null ? true : (!this.items[2].doMaterialsMatch(itemstack) ? false : (this.items[2].count + itemstack.count <= this.getMaxStackSize() && this.items[2].count < this.items[2].getMaxStackSize() ? true : this.items[2].count + itemstack.count <= itemstack.getMaxStackSize())));
         }
     }
 
@@ -198,11 +266,38 @@
         if (this.canBurn()) {
             ItemStack itemstack = RecipesFurnace.getInstance().getResult(this.items[0]);
 
+            // CraftBukkit start - fire FurnaceSmeltEvent
+            CraftItemStack source = CraftItemStack.asCraftMirror(this.items[0]);
+            org.bukkit.inventory.ItemStack result = CraftItemStack.asBukkitCopy(itemstack);
+
+            FurnaceSmeltEvent furnaceSmeltEvent = new FurnaceSmeltEvent(this.world.getWorld().getBlockAt(position.getX(), position.getY(), position.getZ()), source, result);
+            this.world.getServer().getPluginManager().callEvent(furnaceSmeltEvent);
+
+            if (furnaceSmeltEvent.isCancelled()) {
+                return;
+            }
+
+            result = furnaceSmeltEvent.getResult();
+            itemstack = CraftItemStack.asNMSCopy(result);
+
+            if (itemstack != null) {
+                if (this.items[2] == null) {
+                    this.items[2] = itemstack;
+                } else if (CraftItemStack.asCraftMirror(this.items[2]).isSimilar(result)) {
+                    this.items[2].count += itemstack.count;
+                } else {
+                    return;
+                }
+            }
+
+            /*
             if (this.items[2] == null) {
                 this.items[2] = itemstack.cloneItemStack();
             } else if (this.items[2].getItem() == itemstack.getItem()) {
                 ++this.items[2].count;
             }
+            */
+            // CraftBukkit end
 
             if (this.items[0].getItem() == Item.getItemOf(Blocks.SPONGE) && this.items[0].getData() == 1 && this.items[1] != null && this.items[1].getItem() == Items.BUCKET) {
                 this.items[1] = new ItemStack(Items.WATER_BUCKET);