From 61f3fd78a43d60270a91c422793b910112f56c47 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Wed, 27 Apr 2016 22:09:52 -0400
Subject: [PATCH] Optimize Hoppers

* Removes unnecessary extra calls to .update() that are very expensive
* Lots of itemstack cloning removed. Only clone if the item is actually moved
* Return true when a plugin cancels inventory move item event instead of false, as false causes pulls to cycle through all items.
  However, pushes do not exhibit the same behavior, so this is not something plugins could of been relying on.
* Add option (Default on) to cooldown hoppers when they fail to move an item due to full inventory
* Skip subsequent InventoryMoveItemEvents if a plugin does not use the item after first event fire for an iteration

diff --git a/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java b/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
index a5b4f99901..2b5402b009 100644
--- a/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
+++ b/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
@@ -360,6 +360,15 @@ public class PaperWorldConfig {
         squidMaxSpawnHeight = getDouble("squid-spawn-height.maximum", 0.0D);
     }
 
+    public boolean cooldownHopperWhenFull = true;
+    public boolean disableHopperMoveEvents = false;
+    private void hopperOptimizations() {
+        cooldownHopperWhenFull = getBoolean("hopper.cooldown-when-full", cooldownHopperWhenFull);
+        log("Cooldown Hoppers when Full: " + (cooldownHopperWhenFull ? "enabled" : "disabled"));
+        disableHopperMoveEvents = getBoolean("hopper.disable-move-event", disableHopperMoveEvents);
+        log("Hopper Move Item Events: " + (disableHopperMoveEvents ? "disabled" : "enabled"));
+    }
+
     public boolean disableSprintInterruptionOnAttack;
     private void disableSprintInterruptionOnAttack() {
         disableSprintInterruptionOnAttack = getBoolean("game-mechanics.disable-sprint-interruption-on-attack", false);
diff --git a/src/main/java/net/minecraft/server/ItemStack.java b/src/main/java/net/minecraft/server/ItemStack.java
index ca1bd02995..2d83c9e79c 100644
--- a/src/main/java/net/minecraft/server/ItemStack.java
+++ b/src/main/java/net/minecraft/server/ItemStack.java
@@ -482,8 +482,9 @@ public final class ItemStack {
         return this.getItem().a(this, entityhuman, entityliving, enumhand);
     }
 
-    public ItemStack cloneItemStack() {
-        ItemStack itemstack = new ItemStack(this.getItem(), this.count);
+    public ItemStack cloneItemStack() { return cloneItemStack(false); } // Paper
+    public ItemStack cloneItemStack(boolean origItem) { // Paper
+        ItemStack itemstack = new ItemStack(origItem ? this.item : this.getItem(), this.count); // Paper
 
         itemstack.d(this.C());
         if (this.tag != null) {
diff --git a/src/main/java/net/minecraft/server/MinecraftServer.java b/src/main/java/net/minecraft/server/MinecraftServer.java
index 3f2a3dd178..e5c148c481 100644
--- a/src/main/java/net/minecraft/server/MinecraftServer.java
+++ b/src/main/java/net/minecraft/server/MinecraftServer.java
@@ -1126,6 +1126,7 @@ public abstract class MinecraftServer extends IAsyncTaskHandlerReentrant<TickTas
         for (Iterator iterator = this.getWorlds().iterator(); iterator.hasNext();) {
             WorldServer worldserver = (WorldServer) iterator.next();
             worldserver.hasPhysicsEvent =  org.bukkit.event.block.BlockPhysicsEvent.getHandlerList().getRegisteredListeners().length > 0; // Paper
+            TileEntityHopper.skipHopperEvents = worldserver.paperConfig.disableHopperMoveEvents || org.bukkit.event.inventory.InventoryMoveItemEvent.getHandlerList().getRegisteredListeners().length == 0; // Paper
             i = SystemUtils.getMonotonicNanos();
             if (true || worldserver.worldProvider.getDimensionManager() == DimensionManager.OVERWORLD || this.getAllowNether()) { // CraftBukkit
                 this.methodProfiler.a(() -> {
diff --git a/src/main/java/net/minecraft/server/TileEntity.java b/src/main/java/net/minecraft/server/TileEntity.java
index acce1788db..5188689fbb 100644
--- a/src/main/java/net/minecraft/server/TileEntity.java
+++ b/src/main/java/net/minecraft/server/TileEntity.java
@@ -62,6 +62,7 @@ public abstract class TileEntity implements KeyedObject { // Paper
     public void setCurrentChunk(Chunk chunk) {
         this.currentChunk = chunk != null ? new java.lang.ref.WeakReference<>(chunk) : null;
     }
+    static boolean IGNORE_TILE_UPDATES = false;
     // Paper end
 
     @Nullable
@@ -145,6 +146,7 @@ public abstract class TileEntity implements KeyedObject { // Paper
 
     public void update() {
         if (this.world != null) {
+            if (IGNORE_TILE_UPDATES) return; // Paper
             this.c = this.world.getType(this.position);
             this.world.b(this.position, this);
             if (!this.c.isAir()) {
diff --git a/src/main/java/net/minecraft/server/TileEntityHopper.java b/src/main/java/net/minecraft/server/TileEntityHopper.java
index d2833f8842..72b4b19d7a 100644
--- a/src/main/java/net/minecraft/server/TileEntityHopper.java
+++ b/src/main/java/net/minecraft/server/TileEntityHopper.java
@@ -189,6 +189,154 @@ public class TileEntityHopper extends TileEntityLootable implements IHopper, ITi
         return false;
     }
 
+    // Paper start - Optimize Hoppers
+    private static boolean skipPullModeEventFire = false;
+    private static boolean skipPushModeEventFire = false;
+    static boolean skipHopperEvents = false;
+
+    private boolean hopperPush(IInventory iinventory, EnumDirection enumdirection) {
+        skipPushModeEventFire = skipHopperEvents;
+        boolean foundItem = false;
+        for (int i = 0; i < this.getSize(); ++i) {
+            if (!this.getItem(i).isEmpty()) {
+                foundItem = true;
+                ItemStack origItemStack = this.getItem(i);
+                ItemStack itemstack = origItemStack;
+
+                final int origCount = origItemStack.getCount();
+                final int moved = Math.min(world.spigotConfig.hopperAmount, origCount);
+                origItemStack.setCount(moved);
+
+                // We only need to fire the event once to give protection plugins a chance to cancel this event
+                // Because nothing uses getItem, every event call should end up the same result.
+                if (!skipPushModeEventFire) {
+                    itemstack = callPushMoveEvent(iinventory, itemstack);
+                    if (itemstack == null) { // cancelled
+                        origItemStack.setCount(origCount);
+                        return false;
+                    }
+                }
+                final ItemStack itemstack2 = addItem(this, iinventory, itemstack, enumdirection);
+                final int remaining = itemstack2.getCount();
+                if (remaining != moved) {
+                    origItemStack = origItemStack.cloneItemStack(true);
+                    origItemStack.setCount(origCount - moved + remaining);
+                    this.setItem(i, origItemStack);
+                    iinventory.update();
+                    return true;
+                }
+                origItemStack.setCount(origCount);
+            }
+        }
+        if (foundItem && world.paperConfig.cooldownHopperWhenFull) { // Inventory was full - cooldown
+            this.setCooldown(world.spigotConfig.hopperTransfer);
+        }
+        return false;
+    }
+
+    private static boolean hopperPull(IHopper ihopper, IInventory iinventory, int i) {
+        ItemStack origItemStack = iinventory.getItem(i);
+        ItemStack itemstack = origItemStack;
+        final int origCount = origItemStack.getCount();
+        final World world = ihopper.getWorld();
+        final int moved = Math.min(world.spigotConfig.hopperAmount, origCount);
+        itemstack.setCount(moved);
+
+        if (!skipPullModeEventFire) {
+            itemstack = callPullMoveEvent(ihopper, iinventory, itemstack);
+            if (itemstack == null) { // cancelled
+                origItemStack.setCount(origCount);
+                // Drastically improve performance by returning true.
+                // No plugin could of relied on the behavior of false as the other call
+                // site for IMIE did not exhibit the same behavior
+                return true;
+            }
+        }
+
+        final ItemStack itemstack2 = addItem(iinventory, ihopper, itemstack, null);
+        final int remaining = itemstack2.getCount();
+        if (remaining != moved) {
+            origItemStack = origItemStack.cloneItemStack(true);
+            origItemStack.setCount(origCount - moved + remaining);
+            IGNORE_TILE_UPDATES = true;
+            iinventory.setItem(i, origItemStack);
+            IGNORE_TILE_UPDATES = false;
+            iinventory.update();
+            return true;
+        }
+        origItemStack.setCount(origCount);
+
+        if (world.paperConfig.cooldownHopperWhenFull) {
+            cooldownHopper(ihopper);
+        }
+
+        return false;
+    }
+
+    private ItemStack callPushMoveEvent(IInventory iinventory, ItemStack itemstack) {
+        Inventory destinationInventory = getInventory(iinventory);
+        InventoryMoveItemEvent event = new InventoryMoveItemEvent(this.getOwner(false).getInventory(),
+            CraftItemStack.asCraftMirror(itemstack), destinationInventory, true);
+        boolean result = event.callEvent();
+        if (!event.calledGetItem && !event.calledSetItem) {
+            skipPushModeEventFire = true;
+        }
+        if (!result) {
+            cooldownHopper(this);
+            return null;
+        }
+
+        if (event.calledSetItem) {
+            return CraftItemStack.asNMSCopy(event.getItem());
+        } else {
+            return itemstack;
+        }
+    }
+
+    private static ItemStack callPullMoveEvent(IHopper hopper, IInventory iinventory, ItemStack itemstack) {
+        Inventory sourceInventory = getInventory(iinventory);
+        Inventory destination = getInventory(hopper);
+
+        InventoryMoveItemEvent event = new InventoryMoveItemEvent(sourceInventory,
+            // Mirror is safe as we no plugins ever use this item
+            CraftItemStack.asCraftMirror(itemstack), destination, false);
+        boolean result = event.callEvent();
+        if (!event.calledGetItem && !event.calledSetItem) {
+            skipPullModeEventFire = true;
+        }
+        if (!result) {
+            cooldownHopper(hopper);
+            return null;
+        }
+
+        if (event.calledSetItem) {
+            return CraftItemStack.asNMSCopy(event.getItem());
+        } else {
+            return itemstack;
+        }
+    }
+
+    private static Inventory getInventory(IInventory iinventory) {
+        Inventory sourceInventory;// Have to special case large chests as they work oddly
+        if (iinventory instanceof InventoryLargeChest) {
+            sourceInventory = new org.bukkit.craftbukkit.inventory.CraftInventoryDoubleChest((InventoryLargeChest) iinventory);
+        } else if (iinventory instanceof TileEntity) {
+            sourceInventory = ((TileEntity) iinventory).getOwner(false).getInventory();
+        } else {
+            sourceInventory = iinventory.getOwner().getInventory();
+        }
+        return sourceInventory;
+    }
+
+    private static void cooldownHopper(IHopper hopper) {
+        if (hopper instanceof TileEntityHopper) {
+            ((TileEntityHopper) hopper).setCooldown(hopper.getWorld().spigotConfig.hopperTransfer);
+        } else if (hopper instanceof EntityMinecartHopper) {
+            ((EntityMinecartHopper) hopper).setCooldown(hopper.getWorld().spigotConfig.hopperTransfer / 2);
+        }
+    }
+    // Paper end
+
     private boolean t() {
         IInventory iinventory = this.u();
 
@@ -200,6 +348,7 @@ public class TileEntityHopper extends TileEntityLootable implements IHopper, ITi
             if (this.b(iinventory, enumdirection)) {
                 return false;
             } else {
+                return hopperPush(iinventory, enumdirection); /* // Paper - disable rest
                 for (int i = 0; i < this.getSize(); ++i) {
                     if (!this.getItem(i).isEmpty()) {
                         ItemStack itemstack = this.getItem(i).cloneItemStack();
@@ -237,7 +386,7 @@ public class TileEntityHopper extends TileEntityLootable implements IHopper, ITi
                     }
                 }
 
-                return false;
+                return false;*/ // Paper - end commenting out replaced block for Hopper Optimizations
             }
         }
     }
@@ -267,6 +416,7 @@ public class TileEntityHopper extends TileEntityLootable implements IHopper, ITi
             EnumDirection enumdirection = EnumDirection.DOWN;
 
             return c(iinventory, enumdirection) ? false : a(iinventory, enumdirection).anyMatch((i) -> {
+                skipPullModeEventFire = skipHopperEvents; // Paper
                 return a(ihopper, iinventory, i, enumdirection);
             });
         } else {
@@ -290,6 +440,7 @@ public class TileEntityHopper extends TileEntityLootable implements IHopper, ITi
         ItemStack itemstack = iinventory.getItem(i);
 
         if (!itemstack.isEmpty() && b(iinventory, itemstack, i, enumdirection)) {
+            return hopperPull(ihopper, iinventory, i); /* // Paper - disable rest
             ItemStack itemstack1 = itemstack.cloneItemStack();
             // ItemStack itemstack2 = addItem(iinventory, ihopper, iinventory.splitStack(i, 1), (EnumDirection) null);
             // CraftBukkit start - Call event on collection of items from inventories into the hopper
@@ -326,7 +477,7 @@ public class TileEntityHopper extends TileEntityLootable implements IHopper, ITi
             }
 
             itemstack1.subtract(origCount - itemstack2.getCount()); // Spigot
-            iinventory.setItem(i, itemstack1);
+            iinventory.setItem(i, itemstack1);*/ // Paper - end commenting out replaced block for Hopper Optimizations
         }
 
         return false;
@@ -335,7 +486,7 @@ public class TileEntityHopper extends TileEntityLootable implements IHopper, ITi
     public static boolean a(IInventory iinventory, EntityItem entityitem) {
         boolean flag = false;
         // CraftBukkit start
-        InventoryPickupItemEvent event = new InventoryPickupItemEvent(iinventory.getOwner().getInventory(), (org.bukkit.entity.Item) entityitem.getBukkitEntity());
+        InventoryPickupItemEvent event = new InventoryPickupItemEvent(getInventory(iinventory), (org.bukkit.entity.Item) entityitem.getBukkitEntity()); // Paper - use getInventory() to avoid snapshot creation
         entityitem.world.getServer().getPluginManager().callEvent(event);
         if (event.isCancelled()) {
             return false;
@@ -389,7 +540,9 @@ public class TileEntityHopper extends TileEntityLootable implements IHopper, ITi
             boolean flag1 = iinventory1.isNotEmpty();
 
             if (itemstack1.isEmpty()) {
+                IGNORE_TILE_UPDATES = true; // Paper
                 iinventory1.setItem(i, itemstack);
+                IGNORE_TILE_UPDATES = false; // Paper
                 itemstack = ItemStack.a;
                 flag = true;
             } else if (a(itemstack1, itemstack)) {
-- 
2.21.0

