Rough OffHand implementation

this doesn't do stuff like taking arrows from offhand yet.

src/entity/Entity.php

@@ -1599,6 +1599,7 @@ abstract class Entity{
 		$properties->setLong(EntityMetadataProperties::TARGET_EID, $this->targetId ?? 0);
 		$properties->setString(EntityMetadataProperties::NAMETAG, $this->nameTag);
 		$properties->setString(EntityMetadataProperties::SCORE_TAG, $this->scoreTag);
+		$properties->setByte(EntityMetadataProperties::COLOR, 0);
 
 		$properties->setGenericFlag(EntityMetadataFlags::AFFECTED_BY_GRAVITY, true);
 		$properties->setGenericFlag(EntityMetadataFlags::CAN_CLIMB, $this->canClimb);

src/entity/ExperienceManager.php

@@ -239,6 +239,7 @@ class ExperienceManager{
 
 	public function onPickupXp(int $xpValue) : void{
 		static $mainHandIndex = -1;
+		static $offHandIndex = -2;
 
 		//TODO: replace this with a more generic equipment getting/setting interface
 		/** @var Durable[] $equipment */
@@ -247,7 +248,9 @@ class ExperienceManager{
 		if(($item = $this->entity->getInventory()->getItemInHand()) instanceof Durable and $item->hasEnchantment(VanillaEnchantments::MENDING())){
 			$equipment[$mainHandIndex] = $item;
 		}
-		//TODO: check offhand
+		if(($item = $this->entity->getOffHandInventory()->getItem(0)) instanceof Durable and $item->hasEnchantment(VanillaEnchantments::MENDING())){
+			$equipment[$offHandIndex] = $item;
+		}
 		foreach($this->entity->getArmorInventory()->getContents() as $k => $armorItem){
 			if($armorItem instanceof Durable and $armorItem->hasEnchantment(VanillaEnchantments::MENDING())){
 				$equipment[$k] = $armorItem;
@@ -263,6 +266,8 @@ class ExperienceManager{
 
 				if($k === $mainHandIndex){
 					$this->entity->getInventory()->setItemInHand($repairItem);
+				}elseif($k === $offHandIndex){
+					$this->entity->getOffHandInventory()->setItem(0, $repairItem);
 				}else{
 					$this->entity->getArmorInventory()->setItem($k, $repairItem);
 				}

src/entity/Human.php

@@ -34,6 +34,7 @@ use pocketmine\inventory\Inventory;
 use pocketmine\inventory\InventoryHolder;
 use pocketmine\inventory\PlayerEnderInventory;
 use pocketmine\inventory\PlayerInventory;
+use pocketmine\inventory\PlayerOffHandInventory;
 use pocketmine\item\enchantment\VanillaEnchantments;
 use pocketmine\item\Item;
 use pocketmine\item\Totem;
@@ -73,6 +74,9 @@ class Human extends Living implements ProjectileSource, InventoryHolder{
 	/** @var PlayerInventory */
 	protected $inventory;
 
+	/** @var PlayerOffHandInventory */
+	protected $offHandInventory;
+
 	/** @var PlayerEnderInventory */
 	protected $enderInventory;
 
@@ -193,6 +197,8 @@ class Human extends Living implements ProjectileSource, InventoryHolder{
 		return $this->inventory;
 	}
 
+	public function getOffHandInventory() : PlayerOffHandInventory{ return $this->offHandInventory; }
+
 	public function getEnderInventory() : PlayerEnderInventory{
 		return $this->enderInventory;
 	}
@@ -218,7 +224,7 @@ class Human extends Living implements ProjectileSource, InventoryHolder{
 		$this->inventory = new PlayerInventory($this);
 		$syncHeldItem = function() : void{
 			foreach($this->getViewers() as $viewer){
-				$viewer->getNetworkSession()->onMobEquipmentChange($this);
+				$viewer->getNetworkSession()->onMobMainHandItemChange($this);
 			}
 		};
 		$this->inventory->getListeners()->add(new CallbackInventoryListener(
@@ -233,6 +239,7 @@ class Human extends Living implements ProjectileSource, InventoryHolder{
 				}
 			}
 		));
+		$this->offHandInventory = new PlayerOffHandInventory($this);
 		$this->enderInventory = new PlayerEnderInventory($this);
 		$this->initHumanData($nbt);
 
@@ -258,6 +265,15 @@ class Human extends Living implements ProjectileSource, InventoryHolder{
 			$this->armorInventory->getListeners()->add(...$armorListeners);
 			$this->inventory->getListeners()->add(...$inventoryListeners);
 		}
+		$offHand = $nbt->getCompoundTag("OffHandItem");
+		if($offHand !== null){
+			$this->offHandInventory->setItem(0, Item::nbtDeserialize($offHand));
+		}
+		$this->offHandInventory->getListeners()->add(CallbackInventoryListener::onAnyChange(function() : void{
+			foreach($this->getViewers() as $viewer){
+				$viewer->getNetworkSession()->onMobOffHandItemChange($this);
+			}
+		}));
 
 		$enderChestInventoryTag = $nbt->getListTag("EnderChestInventory");
 		if($enderChestInventoryTag !== null){
@@ -270,7 +286,7 @@ class Human extends Living implements ProjectileSource, InventoryHolder{
 		$this->inventory->setHeldItemIndex($nbt->getInt("SelectedInventorySlot", 0));
 		$this->inventory->getHeldItemIndexChangeListeners()->add(function(int $oldIndex) : void{
 			foreach($this->getViewers() as $viewer){
-				$viewer->getNetworkSession()->onMobEquipmentChange($this);
+				$viewer->getNetworkSession()->onMobMainHandItemChange($this);
 			}
 		});
 
@@ -309,7 +325,7 @@ class Human extends Living implements ProjectileSource, InventoryHolder{
 
 		$type = $source->getCause();
 		if($type !== EntityDamageEvent::CAUSE_SUICIDE and $type !== EntityDamageEvent::CAUSE_VOID
-			and $this->inventory->getItemInHand() instanceof Totem){ //TODO: check offhand as well (when it's implemented)
+			and ($this->inventory->getItemInHand() instanceof Totem || $this->offHandInventory->getItem(0) instanceof Totem)){
 
 			$compensation = $this->getHealth() - $source->getFinalDamage() - 1;
 			if($compensation < 0){
@@ -335,6 +351,9 @@ class Human extends Living implements ProjectileSource, InventoryHolder{
 			if($hand instanceof Totem){
 				$hand->pop(); //Plugins could alter max stack size
 				$this->inventory->setItemInHand($hand);
+			}elseif(($offHand = $this->offHandInventory->getItem(0)) instanceof Totem){
+				$offHand->pop();
+				$this->offHandInventory->setItem(0, $offHand);
 			}
 		}
 	}
@@ -342,7 +361,8 @@ class Human extends Living implements ProjectileSource, InventoryHolder{
 	public function getDrops() : array{
 		return array_filter(array_merge(
 			$this->inventory !== null ? array_values($this->inventory->getContents()) : [],
-			$this->armorInventory !== null ? array_values($this->armorInventory->getContents()) : []
+			$this->armorInventory !== null ? array_values($this->armorInventory->getContents()) : [],
+			$this->offHandInventory !== null ? array_values($this->offHandInventory->getContents()) : [],
 		), function(Item $item) : bool{ return !$item->hasEnchantment(VanillaEnchantments::VANISHING()); });
 	}
 
@@ -381,6 +401,10 @@ class Human extends Living implements ProjectileSource, InventoryHolder{
 
 			$nbt->setInt("SelectedInventorySlot", $this->inventory->getHeldItemIndex());
 		}
+		$offHandItem = $this->offHandInventory->getItem(0);
+		if(!$offHandItem->isNull()){
+			$nbt->setTag("OffHandItem", $offHandItem->nbtSerialize());
+		}
 
 		if($this->enderInventory !== null){
 			/** @var CompoundTag[] $items */
@@ -437,6 +461,7 @@ class Human extends Living implements ProjectileSource, InventoryHolder{
 		$this->sendData([$player], [EntityMetadataProperties::NAMETAG => new StringMetadataProperty($this->getNameTag())]);
 
 		$player->getNetworkSession()->onMobArmorChange($this);
+		$player->getNetworkSession()->onMobOffHandItemChange($this);
 
 		if(!($this instanceof Player)){
 			$player->getNetworkSession()->sendDataPacket(PlayerListPacket::remove([PlayerListEntry::createRemovalEntry($this->uuid)]));
@@ -466,12 +491,14 @@ class Human extends Living implements ProjectileSource, InventoryHolder{
 	protected function onDispose() : void{
 		$this->inventory->removeAllViewers();
 		$this->inventory->getHeldItemIndexChangeListeners()->clear();
+		$this->offHandInventory->removeAllViewers();
 		$this->enderInventory->removeAllViewers();
 		parent::onDispose();
 	}
 
 	protected function destroyCycles() : void{
 		$this->inventory = null;
+		$this->offHandInventory = null;
 		$this->enderInventory = null;
 		$this->hungerManager = null;
 		$this->xpManager = null;

src/inventory/PlayerOffhandInventory.php

@@ -0,0 +1,38 @@
+<?php
+
+/*
+ *
+ *  ____            _        _   __  __ _                  __  __ ____
+ * |  _ \ ___   ___| | _____| |_|  \/  (_)_ __   ___      |  \/  |  _ \
+ * | |_) / _ \ / __| |/ / _ \ __| |\/| | | '_ \ / _ \_____| |\/| | |_) |
+ * |  __/ (_) | (__|   <  __/ |_| |  | | | | | |  __/_____| |  | |  __/
+ * |_|   \___/ \___|_|\_\___|\__|_|  |_|_|_| |_|\___|     |_|  |_|_|
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * @author PocketMine Team
+ * @link http://www.pocketmine.net/
+ *
+ *
+*/
+
+declare(strict_types=1);
+
+namespace pocketmine\inventory;
+
+use pocketmine\entity\Human;
+
+final class PlayerOffHandInventory extends BaseInventory{
+	/** @var Human */
+	private $holder;
+
+	public function __construct(Human $player){
+		$this->holder = $player;
+		parent::__construct(1);
+	}
+
+	public function getHolder() : Human{ return $this->holder; }
+}

src/network/mcpe/InventoryManager.php

@@ -96,6 +96,7 @@ class InventoryManager{
 		$this->containerOpenCallbacks->add(\Closure::fromCallable([self::class, 'createContainerOpen']));
 
 		$this->add(ContainerIds::INVENTORY, $this->player->getInventory());
+		$this->add(ContainerIds::OFFHAND, $this->player->getOffHandInventory());
 		$this->add(ContainerIds::ARMOR, $this->player->getArmorInventory());
 		$this->add(ContainerIds::UI, $this->player->getCursorInventory());
 

src/network/mcpe/NetworkSession.php

@@ -963,14 +963,18 @@ class NetworkSession{
 
 	/**
 	 * TODO: expand this to more than just humans
-	 * TODO: offhand
 	 */
-	public function onMobEquipmentChange(Human $mob) : void{
+	public function onMobMainHandItemChange(Human $mob) : void{
 		//TODO: we could send zero for slot here because remote players don't need to know which slot was selected
 		$inv = $mob->getInventory();
 		$this->sendDataPacket(MobEquipmentPacket::create($mob->getId(), ItemStackWrapper::legacy(TypeConverter::getInstance()->coreItemStackToNet($inv->getItemInHand())), $inv->getHeldItemIndex(), ContainerIds::INVENTORY));
 	}
 
+	public function onMobOffHandItemChange(Human $mob) : void{
+		$inv = $mob->getOffHandInventory();
+		$this->sendDataPacket(MobEquipmentPacket::create($mob->getId(), ItemStackWrapper::legacy(TypeConverter::getInstance()->coreItemStackToNet($inv->getItem(0))), 0, ContainerIds::OFFHAND));
+	}
+
 	public function onMobArmorChange(Living $mob) : void{
 		$inv = $mob->getArmorInventory();
 		$converter = TypeConverter::getInstance();

src/network/mcpe/handler/InGamePacketHandler.php

@@ -463,11 +463,17 @@ class InGamePacketHandler extends PacketHandler{
 	}
 
 	public function handleMobEquipment(MobEquipmentPacket $packet) : bool{
-		$this->session->getInvManager()->onClientSelectHotbarSlot($packet->hotbarSlot);
-		if(!$this->player->selectHotbarSlot($packet->hotbarSlot)){
-			$this->session->getInvManager()->syncSelectedHotbarSlot();
+		if($packet->windowId === ContainerIds::OFFHAND){
+			return true; //this happens when we put an item into the offhand
 		}
-		return true;
+		if($packet->windowId === ContainerIds::INVENTORY){
+			$this->session->getInvManager()->onClientSelectHotbarSlot($packet->hotbarSlot);
+			if(!$this->player->selectHotbarSlot($packet->hotbarSlot)){
+				$this->session->getInvManager()->syncSelectedHotbarSlot();
+			}
+			return true;
+		}
+		return false;
 	}
 
 	public function handleMobArmorEquipment(MobArmorEquipmentPacket $packet) : bool{

src/player/Player.php

@@ -2103,6 +2103,9 @@ class Player extends Human implements CommandSender, ChunkListener, IPlayer{
 			if($this->armorInventory !== null){
 				$this->armorInventory->clearAll();
 			}
+			if($this->offHandInventory !== null){
+				$this->offHandInventory->clearAll();
+			}
 		}
 
 		$this->getWorld()->dropExperience($this->location, $ev->getXpDropAmount());

tests/phpstan/configs/gc-hacks.neon

@@ -50,6 +50,11 @@ parameters:
 			count: 1
 			path: ../../../src/entity/Human.php
 
+		-
+			message: "#^Property pocketmine\\\\entity\\\\Human\\:\\:\\$offHandInventory \\(pocketmine\\\\inventory\\\\PlayerOffHandInventory\\) does not accept null\\.$#"
+			count: 1
+			path: ../../../src/entity/Human.php
+
 		-
 			message: "#^Property pocketmine\\\\entity\\\\Human\\:\\:\\$xpManager \\(pocketmine\\\\entity\\\\ExperienceManager\\) does not accept null\\.$#"
 			count: 1