Inventory: reduce API duplication by using a Set for viewers

src/block/tile/BrewingStand.php

@@ -54,7 +54,7 @@ class BrewingStand extends Spawnable implements Container, Nameable{
 	public function __construct(World $world, Vector3 $pos){
 		parent::__construct($world, $pos);
 		$this->inventory = new BrewingStandInventory($this->pos);
-		$this->inventory->addListeners(CallbackInventoryListener::onAnyChange(function(Inventory $unused) : void{
+		$this->inventory->getListeners()->add(CallbackInventoryListener::onAnyChange(function(Inventory $unused) : void{
 			$this->pos->getWorldNonNull()->scheduleDelayedBlockUpdate($this->pos, 1);
 		}));
 	}

src/block/tile/ContainerTrait.php

@@ -48,14 +48,14 @@ trait ContainerTrait{
 			$inventoryTag = $tag->getListTag(Container::TAG_ITEMS);
 
 			$inventory = $this->getRealInventory();
-			$listeners = $inventory->getListeners();
+			$listeners = $inventory->getListeners()->toArray();
-			$inventory->removeListeners(...$listeners); //prevent any events being fired by initialization
+			$inventory->getListeners()->remove(...$listeners); //prevent any events being fired by initialization
 			$inventory->clearAll();
 			/** @var CompoundTag $itemNBT */
 			foreach($inventoryTag as $itemNBT){
 				$inventory->setItem($itemNBT->getByte("Slot"), Item::nbtDeserialize($itemNBT));
 			}
-			$inventory->addListeners(...$listeners);
+			$inventory->getListeners()->add(...$listeners);
 		}
 
 		if($tag->hasTag(Container::TAG_LOCK, StringTag::class)){

src/block/tile/Furnace.php

@@ -58,7 +58,7 @@ class Furnace extends Spawnable implements Container, Nameable{
 	public function __construct(World $world, Vector3 $pos){
 		parent::__construct($world, $pos);
 		$this->inventory = new FurnaceInventory($this->pos);
-		$this->inventory->addListeners(CallbackInventoryListener::onAnyChange(
+		$this->inventory->getListeners()->add(CallbackInventoryListener::onAnyChange(
 			function(Inventory $unused) : void{
 				$this->pos->getWorldNonNull()->scheduleDelayedBlockUpdate($this->pos, 1);
 			})

src/entity/Human.php

@@ -221,8 +221,8 @@ class Human extends Living implements ProjectileSource, InventoryHolder{
 
 		$inventoryTag = $nbt->getListTag("Inventory");
 		if($inventoryTag !== null){
-			$armorListeners = $this->armorInventory->getListeners();
+			$armorListeners = $this->armorInventory->getListeners()->toArray();
-			$this->armorInventory->removeListeners(...$armorListeners);
+			$this->armorInventory->getListeners()->clear();
 
 			/** @var CompoundTag $item */
 			foreach($inventoryTag as $i => $item){
@@ -236,7 +236,7 @@ class Human extends Living implements ProjectileSource, InventoryHolder{
 				}
 			}
 
-			$this->armorInventory->addListeners(...$armorListeners);
+			$this->armorInventory->getListeners()->add(...$armorListeners);
 		}
 
 		$enderChestInventoryTag = $nbt->getListTag("EnderChestInventory");

src/entity/Living.php

@@ -110,7 +110,7 @@ abstract class Living extends Entity{
 
 		$this->armorInventory = new ArmorInventory($this);
 		//TODO: load/save armor inventory contents
-		$this->armorInventory->addListeners(CallbackInventoryListener::onAnyChange(
+		$this->armorInventory->getListeners()->add(CallbackInventoryListener::onAnyChange(
 			function(Inventory $unused) : void{
 				foreach($this->getViewers() as $viewer){
 					$viewer->getNetworkSession()->onMobArmorChange($this);

src/inventory/BaseInventory.php

@@ -23,6 +23,7 @@ declare(strict_types=1);
 
 namespace pocketmine\inventory;
 
+use Ds\Set;
 use pocketmine\item\Item;
 use pocketmine\item\ItemFactory;
 use pocketmine\player\Player;
@@ -43,11 +44,15 @@ abstract class BaseInventory implements Inventory{
 	protected $slots;
 	/** @var Player[] */
 	protected $viewers = [];
-	/** @var InventoryListener[] */
+	/**
-	protected $listeners = [];
+	 * @var InventoryListener[]|Set
+	 * @phpstan-var Set<InventoryListener>
+	 */
+	protected $listeners;
 
 	public function __construct(int $size){
 		$this->slots = new \SplFixedArray($size);
+		$this->listeners = new Set();
 	}
 
 	/**
@@ -92,8 +97,8 @@ abstract class BaseInventory implements Inventory{
 
 		$oldContents = $this->slots->toArray();
 
-		$listeners = $this->listeners;
+		$listeners = $this->listeners->toArray();
-		$this->listeners = [];
+		$this->listeners->clear();
 		$viewers = $this->viewers;
 		$this->viewers = [];
 
@@ -105,7 +110,7 @@ abstract class BaseInventory implements Inventory{
 			}
 		}
 
-		$this->addListeners(...$listeners); //don't directly write, in case listeners were added while operation was in progress
+		$this->listeners->add(...$listeners); //don't directly write, in case listeners were added while operation was in progress
 		foreach($viewers as $id => $viewer){
 			$this->viewers[$id] = $viewer;
 		}
@@ -372,23 +377,7 @@ abstract class BaseInventory implements Inventory{
 		return $slot >= 0 and $slot < $this->slots->getSize();
 	}
 
-	public function addListeners(InventoryListener ...$listeners) : void{
+	public function getListeners() : Set{
-		foreach($listeners as $listener){
-			$this->listeners[spl_object_id($listener)] = $listener;
-		}
-	}
-
-	public function removeListeners(InventoryListener ...$listeners) : void{
-		foreach($listeners as $listener){
-			unset($this->listeners[spl_object_id($listener)]);
-		}
-	}
-
-	public function removeAllListeners() : void{
-		$this->listeners = [];
-	}
-
-	public function getListeners() : array{
 		return $this->listeners;
 	}
 }

src/inventory/Inventory.php

@@ -26,6 +26,7 @@ declare(strict_types=1);
  */
 namespace pocketmine\inventory;
 
+use Ds\Set;
 use pocketmine\item\Item;
 use pocketmine\player\Player;
 
@@ -155,19 +156,8 @@ interface Inventory{
 	public function slotExists(int $slot) : bool;
 
 	/**
-	 * @param InventoryListener ...$listeners
+	 * @return InventoryListener[]|Set
+	 * @phpstan-return Set<InventoryListener>
 	 */
-	public function addListeners(InventoryListener ...$listeners) : void;
+	public function getListeners() : Set;
-
-	/**
-	 * @param InventoryListener ...$listeners
-	 */
-	public function removeListeners(InventoryListener ...$listeners) : void;
-
-	public function removeAllListeners() : void;
-
-	/**
-	 * @return InventoryListener[]
-	 */
-	public function getListeners() : array;
 }

src/inventory/InventoryListener.php

@@ -29,8 +29,7 @@ use pocketmine\item\Item;
  * Classes implementing this interface can be injected into inventories to receive notifications when content changes
  * occur.
  * @see CallbackInventoryListener for a closure-based listener
- * @see Inventory::addListeners()
+ * @see Inventory::getListeners()
- * @see Inventory::removeListeners()
  */
 interface InventoryListener{