PaperMC/paper-server/patches/features/0036-Optimize-Hoppers.patch

From 0000000000000000000000000000000000000000 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 by tracking changes to the event via an internal event implementation.
* Don't check for Entities with Inventories if the block above us is also occluding (not just Inventoried)
* Remove Streams from Item Suck In and restore restore 1.12 AABB checks which is simpler and no voxel allocations (was doing TWO Item Suck ins)

diff --git a/io/papermc/paper/event/inventory/PaperInventoryMoveItemEvent.java b/io/papermc/paper/event/inventory/PaperInventoryMoveItemEvent.java
new file mode 100644
index 0000000000000000000000000000000000000000..24a2090e068ad3c0d08705050944abdfe19136a2
--- /dev/null
+++ b/io/papermc/paper/event/inventory/PaperInventoryMoveItemEvent.java
@@ -0,0 +1,29 @@
+package io.papermc.paper.event.inventory;
+
+import org.bukkit.event.inventory.InventoryMoveItemEvent;
+import org.bukkit.inventory.Inventory;
+import org.bukkit.inventory.ItemStack;
+import org.jspecify.annotations.NullMarked;
+
+@NullMarked
+public class PaperInventoryMoveItemEvent extends InventoryMoveItemEvent {
+
+    public boolean calledSetItem;
+    public boolean calledGetItem;
+
+    public PaperInventoryMoveItemEvent(final Inventory sourceInventory, final ItemStack itemStack, final Inventory destinationInventory, final boolean didSourceInitiate) {
+        super(sourceInventory, itemStack, destinationInventory, didSourceInitiate);
+    }
+
+    @Override
+    public ItemStack getItem() {
+        this.calledGetItem = true;
+        return super.getItem();
+    }
+
+    @Override
+    public void setItem(final ItemStack itemStack) {
+        super.setItem(itemStack);
+        this.calledSetItem = true;
+    }
+}
diff --git a/net/minecraft/server/MinecraftServer.java b/net/minecraft/server/MinecraftServer.java
index 75efd8f11a42696319c0908b7cf911cf976a31b6..b7bb1b6b2c3c892712c44b4e006d9ceebbd8491a 100644
--- a/net/minecraft/server/MinecraftServer.java
+++ b/net/minecraft/server/MinecraftServer.java
@@ -1704,6 +1704,7 @@ public abstract class MinecraftServer extends ReentrantBlockableEventLoop<TickTa
             serverLevel.hasPhysicsEvent = org.bukkit.event.block.BlockPhysicsEvent.getHandlerList().getRegisteredListeners().length > 0; // Paper - BlockPhysicsEvent
             serverLevel.hasEntityMoveEvent = io.papermc.paper.event.entity.EntityMoveEvent.getHandlerList().getRegisteredListeners().length > 0; // Paper - Add EntityMoveEvent
             serverLevel.updateLagCompensationTick(); // Paper - lag compensation
+            net.minecraft.world.level.block.entity.HopperBlockEntity.skipHopperEvents = serverLevel.paperConfig().hopper.disableMoveEvent || org.bukkit.event.inventory.InventoryMoveItemEvent.getHandlerList().getRegisteredListeners().length == 0; // Paper - Perf: Optimize Hoppers
             profilerFiller.push(() -> serverLevel + " " + serverLevel.dimension().location());
             /* Drop global time updates
             if (this.tickCount % 20 == 0) {
diff --git a/net/minecraft/world/item/ItemStack.java b/net/minecraft/world/item/ItemStack.java
index c255e11cb0981bd7e0456d4fd401beb5257be597..d6361863d6a1e364de262d6199373cbd68d1c699 100644
--- a/net/minecraft/world/item/ItemStack.java
+++ b/net/minecraft/world/item/ItemStack.java
@@ -808,10 +808,16 @@ public final class ItemStack implements DataComponentHolder {
     }
 
     public ItemStack copy() {
-        if (this.isEmpty()) {
+        // Paper start - Perf: Optimize Hoppers
+        return this.copy(false);
+    }
+
+    public ItemStack copy(final boolean originalItem) {
+        if (!originalItem && this.isEmpty()) {
+            // Paper end - Perf: Optimize Hoppers
             return EMPTY;
         } else {
-            ItemStack itemStack = new ItemStack(this.getItem(), this.count, this.components.copy());
+            ItemStack itemStack = new ItemStack(originalItem ? this.item : this.getItem(), this.count, this.components.copy()); // Paper - Perf: Optimize Hoppers
             itemStack.setPopTime(this.getPopTime());
             return itemStack;
         }
diff --git a/net/minecraft/world/level/block/entity/BlockEntity.java b/net/minecraft/world/level/block/entity/BlockEntity.java
index 2ebdf1ad323bb53dfe9eed319e25856b35a1443c..77618757c0e678532dbab814aceed83f7f1cd892 100644
--- a/net/minecraft/world/level/block/entity/BlockEntity.java
+++ b/net/minecraft/world/level/block/entity/BlockEntity.java
@@ -26,6 +26,7 @@ import net.minecraft.world.level.block.state.BlockState;
 import org.slf4j.Logger;
 
 public abstract class BlockEntity {
+    static boolean ignoreBlockEntityUpdates; // Paper - Perf: Optimize Hoppers
     // CraftBukkit start - data containers
     private static final org.bukkit.craftbukkit.persistence.CraftPersistentDataTypeRegistry DATA_TYPE_REGISTRY = new org.bukkit.craftbukkit.persistence.CraftPersistentDataTypeRegistry();
     public org.bukkit.craftbukkit.persistence.CraftPersistentDataContainer persistentDataContainer;
@@ -196,6 +197,7 @@ public abstract class BlockEntity {
 
     public void setChanged() {
         if (this.level != null) {
+            if (ignoreBlockEntityUpdates) return; // Paper - Perf: Optimize Hoppers
             setChanged(this.level, this.worldPosition, this.blockState);
         }
     }
diff --git a/net/minecraft/world/level/block/entity/HopperBlockEntity.java b/net/minecraft/world/level/block/entity/HopperBlockEntity.java
index e58a32593e8b42bfc534d13457240860293dd3f4..5cd1326ad5d046c88b2b3449d610a78fa880b4cd 100644
--- a/net/minecraft/world/level/block/entity/HopperBlockEntity.java
+++ b/net/minecraft/world/level/block/entity/HopperBlockEntity.java
@@ -139,18 +139,56 @@ public class HopperBlockEntity extends RandomizableContainerBlockEntity implemen
         }
     }
 
+    // Paper start - Perf: Optimize Hoppers
+    private static final int HOPPER_EMPTY = 0;
+    private static final int HOPPER_HAS_ITEMS = 1;
+    private static final int HOPPER_IS_FULL = 2;
+
+    private static int getFullState(final HopperBlockEntity hopper) {
+        hopper.unpackLootTable(null);
+
+        final List<ItemStack> hopperItems = hopper.items;
+
+        boolean empty = true;
+        boolean full = true;
+
+        for (int i = 0, len = hopperItems.size(); i < len; ++i) {
+            final ItemStack stack = hopperItems.get(i);
+            if (stack.isEmpty()) {
+                full = false;
+                continue;
+            }
+
+            if (!full) {
+                // can't be full
+                return HOPPER_HAS_ITEMS;
+            }
+
+            empty = false;
+
+            if (stack.getCount() != stack.getMaxStackSize()) {
+                // can't be full or empty
+                return HOPPER_HAS_ITEMS;
+            }
+        }
+
+        return empty ? HOPPER_EMPTY : (full ? HOPPER_IS_FULL : HOPPER_HAS_ITEMS);
+    }
+    // Paper end - Perf: Optimize Hoppers
+
     private static boolean tryMoveItems(Level level, BlockPos pos, BlockState state, HopperBlockEntity blockEntity, BooleanSupplier validator) {
         if (level.isClientSide) {
             return false;
         } else {
             if (!blockEntity.isOnCooldown() && state.getValue(HopperBlock.ENABLED)) {
                 boolean flag = false;
-                if (!blockEntity.isEmpty()) {
+                final int fullState = getFullState(blockEntity); // Paper - Perf: Optimize Hoppers
+                if (fullState != HOPPER_EMPTY) { // Paper - Perf: Optimize Hoppers
                     flag = ejectItems(level, pos, blockEntity);
                 }
 
-                if (!blockEntity.inventoryFull()) {
-                    flag |= validator.getAsBoolean();
+                if (fullState != HOPPER_IS_FULL || flag) { // Paper - Perf: Optimize Hoppers
+                    flag |= validator.getAsBoolean(); // Paper - note: this is not a validator, it's what adds/sucks in items
                 }
 
                 if (flag) {
@@ -174,6 +212,206 @@ public class HopperBlockEntity extends RandomizableContainerBlockEntity implemen
         return true;
     }
 
+    // Paper start - Perf: Optimize Hoppers
+    public static boolean skipHopperEvents;
+    private static boolean skipPullModeEventFire;
+    private static boolean skipPushModeEventFire;
+
+    private static boolean hopperPush(final Level level, final Container destination, final Direction direction, final HopperBlockEntity hopper) {
+        skipPushModeEventFire = skipHopperEvents;
+        boolean foundItem = false;
+        for (int i = 0; i < hopper.getContainerSize(); ++i) {
+            final ItemStack item = hopper.getItem(i);
+            if (!item.isEmpty()) {
+                foundItem = true;
+                ItemStack origItemStack = item;
+                ItemStack movedItem = origItemStack;
+
+                final int originalItemCount = origItemStack.getCount();
+                final int movedItemCount = Math.min(level.spigotConfig.hopperAmount, originalItemCount);
+                origItemStack.setCount(movedItemCount);
+
+                // 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) {
+                    movedItem = callPushMoveEvent(destination, movedItem, hopper);
+                    if (movedItem == null) { // cancelled
+                        origItemStack.setCount(originalItemCount);
+                        return false;
+                    }
+                }
+
+                final ItemStack remainingItem = addItem(hopper, destination, movedItem, direction);
+                final int remainingItemCount = remainingItem.getCount();
+                if (remainingItemCount != movedItemCount) {
+                    origItemStack = origItemStack.copy(true);
+                    origItemStack.setCount(originalItemCount);
+                    if (!origItemStack.isEmpty()) {
+                        origItemStack.setCount(originalItemCount - movedItemCount + remainingItemCount);
+                    }
+                    hopper.setItem(i, origItemStack);
+                    destination.setChanged();
+                    return true;
+                }
+                origItemStack.setCount(originalItemCount);
+            }
+        }
+        if (foundItem && level.paperConfig().hopper.cooldownWhenFull) { // Inventory was full - cooldown
+            hopper.setCooldown(level.spigotConfig.hopperTransfer);
+        }
+        return false;
+    }
+
+    private static boolean hopperPull(final Level level, final Hopper hopper, final Container container, ItemStack origItemStack, final int i) {
+        ItemStack movedItem = origItemStack;
+        final int originalItemCount = origItemStack.getCount();
+        final int movedItemCount = Math.min(level.spigotConfig.hopperAmount, originalItemCount);
+        container.setChanged(); // original logic always marks source inv as changed even if no move happens.
+        movedItem.setCount(movedItemCount);
+
+        if (!skipPullModeEventFire) {
+            movedItem = callPullMoveEvent(hopper, container, movedItem);
+            if (movedItem == null) { // cancelled
+                origItemStack.setCount(originalItemCount);
+                // Drastically improve performance by returning true.
+                // No plugin could have relied on the behavior of false as the other call
+                // site for IMIE did not exhibit the same behavior
+                return true;
+            }
+        }
+
+        final ItemStack remainingItem = addItem(container, hopper, movedItem, null);
+        final int remainingItemCount = remainingItem.getCount();
+        if (remainingItemCount != movedItemCount) {
+            origItemStack = origItemStack.copy(true);
+            origItemStack.setCount(originalItemCount);
+            if (!origItemStack.isEmpty()) {
+                origItemStack.setCount(originalItemCount - movedItemCount + remainingItemCount);
+            }
+
+            ignoreBlockEntityUpdates = true;
+            container.setItem(i, origItemStack);
+            ignoreBlockEntityUpdates = false;
+            container.setChanged();
+            return true;
+        }
+        origItemStack.setCount(originalItemCount);
+
+        if (level.paperConfig().hopper.cooldownWhenFull) {
+            applyCooldown(hopper);
+        }
+
+        return false;
+    }
+
+    @Nullable
+    private static ItemStack callPushMoveEvent(Container destination, ItemStack itemStack, HopperBlockEntity hopper) {
+        final org.bukkit.inventory.Inventory destinationInventory = getInventory(destination);
+        final io.papermc.paper.event.inventory.PaperInventoryMoveItemEvent event = new io.papermc.paper.event.inventory.PaperInventoryMoveItemEvent(
+            hopper.getOwner(false).getInventory(),
+            org.bukkit.craftbukkit.inventory.CraftItemStack.asCraftMirror(itemStack),
+            destinationInventory,
+            true
+        );
+        final boolean result = event.callEvent();
+        if (!event.calledGetItem && !event.calledSetItem) {
+            skipPushModeEventFire = true;
+        }
+        if (!result) {
+            applyCooldown(hopper);
+            return null;
+        }
+
+        if (event.calledSetItem) {
+            return org.bukkit.craftbukkit.inventory.CraftItemStack.asNMSCopy(event.getItem());
+        } else {
+            return itemStack;
+        }
+    }
+
+    @Nullable
+    private static ItemStack callPullMoveEvent(final Hopper hopper, final Container container, final ItemStack itemstack) {
+        final org.bukkit.inventory.Inventory sourceInventory = getInventory(container);
+        final org.bukkit.inventory.Inventory destination = getInventory(hopper);
+
+        // Mirror is safe as no plugins ever use this item
+        final io.papermc.paper.event.inventory.PaperInventoryMoveItemEvent event = new io.papermc.paper.event.inventory.PaperInventoryMoveItemEvent(sourceInventory, org.bukkit.craftbukkit.inventory.CraftItemStack.asCraftMirror(itemstack), destination, false);
+        final boolean result = event.callEvent();
+        if (!event.calledGetItem && !event.calledSetItem) {
+            skipPullModeEventFire = true;
+        }
+        if (!result) {
+            applyCooldown(hopper);
+            return null;
+        }
+
+        if (event.calledSetItem) {
+            return org.bukkit.craftbukkit.inventory.CraftItemStack.asNMSCopy(event.getItem());
+        } else {
+            return itemstack;
+        }
+    }
+
+    private static org.bukkit.inventory.Inventory getInventory(final Container container) {
+        final org.bukkit.inventory.Inventory sourceInventory;
+        if (container instanceof net.minecraft.world.CompoundContainer compoundContainer) {
+            // Have to special-case large chests as they work oddly
+            sourceInventory = new org.bukkit.craftbukkit.inventory.CraftInventoryDoubleChest(compoundContainer);
+        } else if (container instanceof BlockEntity blockEntity) {
+            sourceInventory = blockEntity.getOwner(false).getInventory();
+        } else if (container.getOwner() != null) {
+            sourceInventory = container.getOwner().getInventory();
+        } else {
+            sourceInventory = new org.bukkit.craftbukkit.inventory.CraftInventory(container);
+        }
+        return sourceInventory;
+    }
+
+    private static void applyCooldown(final Hopper hopper) {
+        if (hopper instanceof HopperBlockEntity blockEntity && blockEntity.getLevel() != null) {
+            blockEntity.setCooldown(blockEntity.getLevel().spigotConfig.hopperTransfer);
+        }
+    }
+
+    private static boolean allMatch(Container container, Direction direction, java.util.function.BiPredicate<ItemStack, Integer> test) {
+        if (container instanceof WorldlyContainer) {
+            for (int slot : ((WorldlyContainer) container).getSlotsForFace(direction)) {
+                if (!test.test(container.getItem(slot), slot)) {
+                    return false;
+                }
+            }
+        } else {
+            int size = container.getContainerSize();
+            for (int slot = 0; slot < size; slot++) {
+                if (!test.test(container.getItem(slot), slot)) {
+                    return false;
+                }
+            }
+        }
+        return true;
+    }
+
+    private static boolean anyMatch(Container container, Direction direction, java.util.function.BiPredicate<ItemStack, Integer> test) {
+        if (container instanceof WorldlyContainer) {
+            for (int slot : ((WorldlyContainer) container).getSlotsForFace(direction)) {
+                if (test.test(container.getItem(slot), slot)) {
+                    return true;
+                }
+            }
+        } else {
+            int size = container.getContainerSize();
+            for (int slot = 0; slot < size; slot++) {
+                if (test.test(container.getItem(slot), slot)) {
+                    return true;
+                }
+            }
+        }
+        return true;
+    }
+    private static final java.util.function.BiPredicate<ItemStack, Integer> STACK_SIZE_TEST = (itemStack, i) -> itemStack.getCount() >= itemStack.getMaxStackSize();
+    private static final java.util.function.BiPredicate<ItemStack, Integer> IS_EMPTY_TEST = (itemStack, i) -> itemStack.isEmpty();
+    // Paper end - Perf: Optimize Hoppers
+
     private static boolean ejectItems(Level level, BlockPos pos, HopperBlockEntity blockEntity) {
         Container attachedContainer = getAttachedContainer(level, pos, blockEntity);
         if (attachedContainer == null) {
@@ -183,57 +421,60 @@ public class HopperBlockEntity extends RandomizableContainerBlockEntity implemen
             if (isFullContainer(attachedContainer, opposite)) {
                 return false;
             } else {
-                for (int i = 0; i < blockEntity.getContainerSize(); i++) {
-                    ItemStack item = blockEntity.getItem(i);
-                    if (!item.isEmpty()) {
-                        int count = item.getCount();
-                        // CraftBukkit start - Call event when pushing items into other inventories
-                        ItemStack original = item.copy();
-                        org.bukkit.craftbukkit.inventory.CraftItemStack oitemstack = org.bukkit.craftbukkit.inventory.CraftItemStack.asCraftMirror(
-                            blockEntity.removeItem(i, level.spigotConfig.hopperAmount)
-                        ); // Spigot
-
-                        org.bukkit.inventory.Inventory destinationInventory;
-                        // Have to special case large chests as they work oddly
-                        if (attachedContainer instanceof final net.minecraft.world.CompoundContainer compoundContainer) {
-                            destinationInventory = new org.bukkit.craftbukkit.inventory.CraftInventoryDoubleChest(compoundContainer);
-                        } else if (attachedContainer.getOwner() != null) {
-                            destinationInventory = attachedContainer.getOwner().getInventory();
-                        } else {
-                            destinationInventory = new org.bukkit.craftbukkit.inventory.CraftInventory(attachedContainer);
-                        }
-
-                        org.bukkit.event.inventory.InventoryMoveItemEvent event = new org.bukkit.event.inventory.InventoryMoveItemEvent(
-                            blockEntity.getOwner().getInventory(),
-                            oitemstack,
-                            destinationInventory,
-                            true
-                        );
-                        if (!event.callEvent()) {
-                            blockEntity.setItem(i, original);
-                            blockEntity.setCooldown(level.spigotConfig.hopperTransfer); // Delay hopper checks // Spigot
-                            return false;
-                        }
-                        int origCount = event.getItem().getAmount(); // Spigot
-                        ItemStack itemStack = HopperBlockEntity.addItem(blockEntity, attachedContainer, org.bukkit.craftbukkit.inventory.CraftItemStack.asNMSCopy(event.getItem()), opposite);
-                        // CraftBukkit end
-
-                        if (itemStack.isEmpty()) {
-                            attachedContainer.setChanged();
-                            return true;
-                        }
-
-                        item.setCount(count);
-                        // Spigot start
-                        item.shrink(origCount - itemStack.getCount());
-                        if (count <= level.spigotConfig.hopperAmount) {
-                            // Spigot end
-                            blockEntity.setItem(i, item);
-                        }
-                    }
-                }
-
-                return false;
+                // Paper start - Perf: Optimize Hoppers
+                return hopperPush(level, attachedContainer, opposite, blockEntity);
+                //for (int i = 0; i < blockEntity.getContainerSize(); i++) {
+                //    ItemStack item = blockEntity.getItem(i);
+                //    if (!item.isEmpty()) {
+                //        int count = item.getCount();
+                //        // CraftBukkit start - Call event when pushing items into other inventories
+                //        ItemStack original = item.copy();
+                //        org.bukkit.craftbukkit.inventory.CraftItemStack oitemstack = org.bukkit.craftbukkit.inventory.CraftItemStack.asCraftMirror(
+                //            blockEntity.removeItem(i, level.spigotConfig.hopperAmount)
+                //        ); // Spigot
+
+                //        org.bukkit.inventory.Inventory destinationInventory;
+                //        // Have to special case large chests as they work oddly
+                //        if (attachedContainer instanceof final net.minecraft.world.CompoundContainer compoundContainer) {
+                //            destinationInventory = new org.bukkit.craftbukkit.inventory.CraftInventoryDoubleChest(compoundContainer);
+                //        } else if (attachedContainer.getOwner() != null) {
+                //            destinationInventory = attachedContainer.getOwner().getInventory();
+                //        } else {
+                //            destinationInventory = new org.bukkit.craftbukkit.inventory.CraftInventory(attachedContainer);
+                //        }
+
+                //        org.bukkit.event.inventory.InventoryMoveItemEvent event = new org.bukkit.event.inventory.InventoryMoveItemEvent(
+                //            blockEntity.getOwner().getInventory(),
+                //            oitemstack,
+                //            destinationInventory,
+                //            true
+                //        );
+                //        if (!event.callEvent()) {
+                //            blockEntity.setItem(i, original);
+                //            blockEntity.setCooldown(level.spigotConfig.hopperTransfer); // Delay hopper checks // Spigot
+                //            return false;
+                //        }
+                //        int origCount = event.getItem().getAmount(); // Spigot
+                //        ItemStack itemStack = HopperBlockEntity.addItem(blockEntity, attachedContainer, org.bukkit.craftbukkit.inventory.CraftItemStack.asNMSCopy(event.getItem()), opposite);
+                //        // CraftBukkit end
+
+                //        if (itemStack.isEmpty()) {
+                //            attachedContainer.setChanged();
+                //            return true;
+                //        }
+
+                //        item.setCount(count);
+                //        // Spigot start
+                //        item.shrink(origCount - itemStack.getCount());
+                //        if (count <= level.spigotConfig.hopperAmount) {
+                //            // Spigot end
+                //            blockEntity.setItem(i, item);
+                //        }
+                //    }
+                //}
+
+                //return false;
+                // Paper end - Perf: Optimize Hoppers
             }
         }
     }
@@ -288,6 +529,7 @@ public class HopperBlockEntity extends RandomizableContainerBlockEntity implemen
         Container sourceContainer = getSourceContainer(level, hopper, blockPos, blockState);
         if (sourceContainer != null) {
             Direction direction = Direction.DOWN;
+            skipPullModeEventFire = skipHopperEvents; // Paper - Perf: Optimize Hoppers
 
             for (int i : getSlots(sourceContainer, direction)) {
                 if (tryTakeInItemFromSlot(hopper, sourceContainer, i, direction, level)) { // Spigot
@@ -313,55 +555,58 @@ public class HopperBlockEntity extends RandomizableContainerBlockEntity implemen
     private static boolean tryTakeInItemFromSlot(Hopper hopper, Container container, int slot, Direction direction, Level level) { // Spigot
         ItemStack item = container.getItem(slot);
         if (!item.isEmpty() && canTakeItemFromContainer(hopper, container, item, slot, direction)) {
-            int count = item.getCount();
-            // CraftBukkit start - Call event on collection of items from inventories into the hopper
-            ItemStack original = item.copy();
-            org.bukkit.craftbukkit.inventory.CraftItemStack oitemstack = org.bukkit.craftbukkit.inventory.CraftItemStack.asCraftMirror(
-                container.removeItem(slot, level.spigotConfig.hopperAmount) // Spigot
-            );
-
-            org.bukkit.inventory.Inventory sourceInventory;
-            // Have to special case large chests as they work oddly
-            if (container instanceof final net.minecraft.world.CompoundContainer compoundContainer) {
-                sourceInventory = new org.bukkit.craftbukkit.inventory.CraftInventoryDoubleChest(compoundContainer);
-            } else if (container.getOwner() != null) {
-                sourceInventory = container.getOwner().getInventory();
-            } else {
-                sourceInventory = new org.bukkit.craftbukkit.inventory.CraftInventory(container);
-            }
-
-            org.bukkit.event.inventory.InventoryMoveItemEvent event = new org.bukkit.event.inventory.InventoryMoveItemEvent(
-                sourceInventory,
-                oitemstack,
-                hopper.getOwner().getInventory(),
-                false
-            );
-
-            if (!event.callEvent()) {
-                container.setItem(slot, original);
-
-                if (hopper instanceof final HopperBlockEntity hopperBlockEntity) {
-                    hopperBlockEntity.setCooldown(level.spigotConfig.hopperTransfer); // Spigot
-                }
-
-                return false;
-            }
-            int origCount = event.getItem().getAmount(); // Spigot
-            ItemStack itemStack = HopperBlockEntity.addItem(container, hopper, org.bukkit.craftbukkit.inventory.CraftItemStack.asNMSCopy(event.getItem()), null);
-            // CraftBukkit end
-
-            if (itemStack.isEmpty()) {
-                container.setChanged();
-                return true;
-            }
-
-            item.setCount(count);
-            // Spigot start
-            item.shrink(origCount - itemStack.getCount());
-            if (count <= level.spigotConfig.hopperAmount) {
-                // Spigot end
-                container.setItem(slot, item);
-            }
+            // Paper start - Perf: Optimize Hoppers
+            return hopperPull(level, hopper, container, item, slot);
+            //int count = item.getCount();
+            //// CraftBukkit start - Call event on collection of items from inventories into the hopper
+            //ItemStack original = item.copy();
+            //org.bukkit.craftbukkit.inventory.CraftItemStack oitemstack = org.bukkit.craftbukkit.inventory.CraftItemStack.asCraftMirror(
+            //    container.removeItem(slot, level.spigotConfig.hopperAmount) // Spigot
+            //);
+
+            //org.bukkit.inventory.Inventory sourceInventory;
+            //// Have to special case large chests as they work oddly
+            //if (container instanceof final net.minecraft.world.CompoundContainer compoundContainer) {
+            //    sourceInventory = new org.bukkit.craftbukkit.inventory.CraftInventoryDoubleChest(compoundContainer);
+            //} else if (container.getOwner() != null) {
+            //    sourceInventory = container.getOwner().getInventory();
+            //} else {
+            //    sourceInventory = new org.bukkit.craftbukkit.inventory.CraftInventory(container);
+            //}
+
+            //org.bukkit.event.inventory.InventoryMoveItemEvent event = new org.bukkit.event.inventory.InventoryMoveItemEvent(
+            //    sourceInventory,
+            //    oitemstack,
+            //    hopper.getOwner().getInventory(),
+            //    false
+            //);
+
+            //if (!event.callEvent()) {
+            //    container.setItem(slot, original);
+
+            //    if (hopper instanceof final HopperBlockEntity hopperBlockEntity) {
+            //        hopperBlockEntity.setCooldown(level.spigotConfig.hopperTransfer); // Spigot
+            //    }
+
+            //    return false;
+            //}
+            //int origCount = event.getItem().getAmount(); // Spigot
+            //ItemStack itemStack = HopperBlockEntity.addItem(container, hopper, org.bukkit.craftbukkit.inventory.CraftItemStack.asNMSCopy(event.getItem()), null);
+            //// CraftBukkit end
+
+            //if (itemStack.isEmpty()) {
+            //    container.setChanged();
+            //    return true;
+            //}
+
+            //item.setCount(count);
+            //// Spigot start
+            //item.shrink(origCount - itemStack.getCount());
+            //if (count <= level.spigotConfig.hopperAmount) {
+            //    // Spigot end
+            //    container.setItem(slot, item);
+            //}
+            // Paper end - Perf: Optimize Hoppers
         }
 
         return false;
@@ -370,13 +615,15 @@ public class HopperBlockEntity extends RandomizableContainerBlockEntity implemen
     public static boolean addItem(Container container, ItemEntity item) {
         boolean flag = false;
         // CraftBukkit start
+        if (org.bukkit.event.inventory.InventoryPickupItemEvent.getHandlerList().getRegisteredListeners().length > 0) { // Paper - optimize hoppers
         org.bukkit.event.inventory.InventoryPickupItemEvent event = new org.bukkit.event.inventory.InventoryPickupItemEvent(
-            container.getOwner().getInventory(), (org.bukkit.entity.Item) item.getBukkitEntity()
+            getInventory(container), (org.bukkit.entity.Item) item.getBukkitEntity() // Paper - Perf: Optimize Hoppers; use getInventory() to avoid snapshot creation
         );
         if (!event.callEvent()) {
             return false;
         }
         // CraftBukkit end
+        } // Paper - Perf: Optimize Hoppers
         ItemStack itemStack = item.getItem().copy();
         ItemStack itemStack1 = addItem(null, container, itemStack, null);
         if (itemStack1.isEmpty()) {
@@ -431,7 +678,9 @@ public class HopperBlockEntity extends RandomizableContainerBlockEntity implemen
                     stack = stack.split(destination.getMaxStackSize());
                 }
                 // Spigot end
+                ignoreBlockEntityUpdates = true; // Paper - Perf: Optimize Hoppers
                 destination.setItem(slot, stack);
+                ignoreBlockEntityUpdates = false; // Paper - Perf: Optimize Hoppers
                 stack = leftover; // Paper - Make hoppers respect inventory max stack size
                 flag = true;
             } else if (canMergeItems(item, stack)) {
@@ -519,13 +768,19 @@ public class HopperBlockEntity extends RandomizableContainerBlockEntity implemen
 
     @Nullable
     public static Container getContainerAt(Level level, BlockPos pos) {
-        return getContainerAt(level, pos, level.getBlockState(pos), pos.getX() + 0.5, pos.getY() + 0.5, pos.getZ() + 0.5);
+        return getContainerAt(level, pos, level.getBlockState(pos), pos.getX() + 0.5, pos.getY() + 0.5, pos.getZ() + 0.5, true); // Paper - Optimize hoppers
     }
 
     @Nullable
     private static Container getContainerAt(Level level, BlockPos pos, BlockState state, double x, double y, double z) {
+        // Paper start - Perf: Optimize Hoppers
+        return HopperBlockEntity.getContainerAt(level, pos, state, x, y, z, false);
+    }
+    @Nullable
+    private static Container getContainerAt(Level level, BlockPos pos, BlockState state, double x, double y, double z, final boolean optimizeEntities) {
+        // Paper end - Perf: Optimize Hoppers
         Container blockContainer = getBlockContainer(level, pos, state);
-        if (blockContainer == null) {
+        if (blockContainer == null && (!optimizeEntities || !level.paperConfig().hopper.ignoreOccludingBlocks || !state.getBukkitMaterial().isOccluding())) { // Paper - Perf: Optimize Hoppers
             blockContainer = getEntityContainer(level, x, y, z);
         }
 
@@ -551,14 +806,14 @@ public class HopperBlockEntity extends RandomizableContainerBlockEntity implemen
 
     @Nullable
     private static Container getEntityContainer(Level level, double x, double y, double z) {
-        List<Entity> entities = level.getEntities(
-            (Entity)null, new AABB(x - 0.5, y - 0.5, z - 0.5, x + 0.5, y + 0.5, z + 0.5), EntitySelector.CONTAINER_ENTITY_SELECTOR
+        List<Entity> entities = level.getEntitiesOfClass(
+            (Class) Container.class, new AABB(x - 0.5, y - 0.5, z - 0.5, x + 0.5, y + 0.5, z + 0.5), EntitySelector.CONTAINER_ENTITY_SELECTOR // Paper - Perf: Optimize hoppers
         );
         return !entities.isEmpty() ? (Container)entities.get(level.random.nextInt(entities.size())) : null;
     }
 
     private static boolean canMergeItems(ItemStack stack1, ItemStack stack2) {
-        return stack1.getCount() <= stack1.getMaxStackSize() && ItemStack.isSameItemSameComponents(stack1, stack2);
+        return stack1.getCount() < stack1.getMaxStackSize() && ItemStack.isSameItemSameComponents(stack1, stack2); // Paper - Perf: Optimize Hoppers; used to return true for full itemstacks?!
     }
 
     @Override
diff --git a/net/minecraft/world/level/block/entity/RandomizableContainerBlockEntity.java b/net/minecraft/world/level/block/entity/RandomizableContainerBlockEntity.java
index 73b3ddb120d6b6f89e478960e78bed415baea205..f9c31da81d84033abfc1179fc643bceffe35da17 100644
--- a/net/minecraft/world/level/block/entity/RandomizableContainerBlockEntity.java
+++ b/net/minecraft/world/level/block/entity/RandomizableContainerBlockEntity.java
@@ -53,7 +53,7 @@ public abstract class RandomizableContainerBlockEntity extends BaseContainerBloc
 
     @Override
     public ItemStack getItem(int index) {
-        this.unpackLootTable(null);
+        if (index == 0) this.unpackLootTable(null); // Paper - Perf: Optimize Hoppers
         return super.getItem(index);
     }