Use a server impl for hopper event to track get/setItem calls (#9905)

* Use a server impl for hopper event to track getItem/setItem calls

* Rebase

* Comments

patches/api/Optimize-Hoppers.patch

@@ -3,37 +3,17 @@ From: Aikar <aikar@aikar.co>
 Date: Thu, 18 Jan 2018 01:00:27 -0500
 Subject: [PATCH] Optimize Hoppers
 
-Adds data about what Item related methods were used in InventoryMoveItem event
-so that the server can improve the performance of this event.
 
 diff --git a/src/main/java/org/bukkit/event/inventory/InventoryMoveItemEvent.java b/src/main/java/org/bukkit/event/inventory/InventoryMoveItemEvent.java
 index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
 --- a/src/main/java/org/bukkit/event/inventory/InventoryMoveItemEvent.java
 +++ b/src/main/java/org/bukkit/event/inventory/InventoryMoveItemEvent.java
-@@ -0,0 +0,0 @@ public class InventoryMoveItemEvent extends Event implements Cancellable {
-     private final Inventory destinationInventory;
-     private ItemStack itemStack;
-     private final boolean didSourceInitiate;
-+    public boolean calledGetItem; // Paper
-+    public boolean calledSetItem; // Paper
- 
-     public InventoryMoveItemEvent(@NotNull final Inventory sourceInventory, @NotNull final ItemStack itemStack, @NotNull final Inventory destinationInventory, final boolean didSourceInitiate) {
-         Preconditions.checkArgument(itemStack != null, "ItemStack cannot be null");
 @@ -0,0 +0,0 @@ public class InventoryMoveItemEvent extends Event implements Cancellable {
       */
      @NotNull
      public ItemStack getItem() {
 -        return itemStack.clone();
-+        calledGetItem = true; // Paper - record this method was used for auto detection of mode
 +        return itemStack; // Paper - Removed clone, handled better in Server
      }
  
      /**
-@@ -0,0 +0,0 @@ public class InventoryMoveItemEvent extends Event implements Cancellable {
-      */
-     public void setItem(@NotNull ItemStack itemStack) {
-         Preconditions.checkArgument(itemStack != null, "ItemStack cannot be null.  Cancel the event if you want nothing to be transferred.");
-+        calledSetItem = true; // Paper - record this method was used for auto detection of mode
-         this.itemStack = itemStack.clone();
-     }
- 

patches/server/Optimize-Hoppers.patch

@@ -8,10 +8,47 @@ Subject: [PATCH] Optimize Hoppers
 * 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
+* 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/src/main/java/io/papermc/paper/event/inventory/PaperInventoryMoveItemEvent.java b/src/main/java/io/papermc/paper/event/inventory/PaperInventoryMoveItemEvent.java
+new file mode 100644
+index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000
+--- /dev/null
++++ b/src/main/java/io/papermc/paper/event/inventory/PaperInventoryMoveItemEvent.java
+@@ -0,0 +0,0 @@
++package io.papermc.paper.event.inventory;
++
++import org.bukkit.event.inventory.InventoryMoveItemEvent;
++import org.bukkit.inventory.Inventory;
++import org.bukkit.inventory.ItemStack;
++import org.checkerframework.checker.nullness.qual.NonNull;
++import org.checkerframework.framework.qual.DefaultQualifier;
++import org.jetbrains.annotations.NotNull;
++
++@DefaultQualifier(NonNull.class)
++public class PaperInventoryMoveItemEvent extends InventoryMoveItemEvent {
++
++    public boolean calledSetItem;
++    public boolean calledGetItem;
++
++    public PaperInventoryMoveItemEvent(final @NotNull Inventory sourceInventory, final @NotNull ItemStack itemStack, final @NotNull 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/src/main/java/net/minecraft/server/MinecraftServer.java b/src/main/java/net/minecraft/server/MinecraftServer.java
 index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
 --- a/src/main/java/net/minecraft/server/MinecraftServer.java
@@ -230,7 +267,7 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 +    @Nullable
 +    private static ItemStack callPushMoveEvent(Container iinventory, ItemStack itemstack, HopperBlockEntity hopper) {
 +        final Inventory destinationInventory = getInventory(iinventory);
-+        final InventoryMoveItemEvent event = new InventoryMoveItemEvent(hopper.getOwner(false).getInventory(),
++        final io.papermc.paper.event.inventory.PaperInventoryMoveItemEvent event = new io.papermc.paper.event.inventory.PaperInventoryMoveItemEvent(hopper.getOwner(false).getInventory(),
 +            CraftItemStack.asCraftMirror(itemstack), destinationInventory, true);
 +        final boolean result = event.callEvent();
 +        if (!event.calledGetItem && !event.calledSetItem) {
@@ -254,7 +291,7 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 +        final Inventory destination = getInventory(hopper);
 +
 +        // Mirror is safe as no plugins ever use this item
-+        final InventoryMoveItemEvent event = new InventoryMoveItemEvent(sourceInventory, CraftItemStack.asCraftMirror(itemstack), destination, false);
++        final io.papermc.paper.event.inventory.PaperInventoryMoveItemEvent event = new io.papermc.paper.event.inventory.PaperInventoryMoveItemEvent(sourceInventory, CraftItemStack.asCraftMirror(itemstack), destination, false);
 +        final boolean result = event.callEvent();
 +        if (!event.calledGetItem && !event.calledSetItem) {
 +            skipPullModeEventFire = true;