Caching creative inventory entries (#5703)

Due to the high cost of Item::serializeCompoundTag(), it's very costly to rebuild this every time we need it. This is sent during the pre-spawn step, where we need to minimize costs as much as possible.

src/inventory/CreativeInventory.php

@@ -25,7 +25,9 @@ namespace pocketmine\inventory;
 
 use pocketmine\item\Durable;
 use pocketmine\item\Item;
+use pocketmine\utils\DestructorCallbackTrait;
 use pocketmine\utils\Filesystem;
+use pocketmine\utils\ObjectSet;
 use pocketmine\utils\SingletonTrait;
 use pocketmine\utils\Utils;
 use Symfony\Component\Filesystem\Path;
@@ -33,11 +35,17 @@ use function json_decode;
 
 final class CreativeInventory{
 	use SingletonTrait;
+	use DestructorCallbackTrait;
 
 	/** @var Item[] */
 	private array $creative = [];
 
+	/** @phpstan-var ObjectSet<\Closure() : void> */
+	private ObjectSet $contentChangedCallbacks;
+
 	private function __construct(){
+		$this->contentChangedCallbacks = new ObjectSet();
+
 		$creativeItems = json_decode(Filesystem::fileGetContents(Path::join(\pocketmine\RESOURCE_PATH, "legacy_creativeitems.json")), true);
 
 		foreach($creativeItems as $data){
@@ -55,6 +63,7 @@ final class CreativeInventory{
 	 */
 	public function clear() : void{
 		$this->creative = [];
+		$this->onContentChange();
 	}
 
 	/**
@@ -84,6 +93,7 @@ final class CreativeInventory{
 	 */
 	public function add(Item $item) : void{
 		$this->creative[] = clone $item;
+		$this->onContentChange();
 	}
 
 	/**
@@ -94,10 +104,22 @@ final class CreativeInventory{
 		$index = $this->getItemIndex($item);
 		if($index !== -1){
 			unset($this->creative[$index]);
+			$this->onContentChange();
 		}
 	}
 
 	public function contains(Item $item) : bool{
 		return $this->getItemIndex($item) !== -1;
 	}
+
+	/** @phpstan-return ObjectSet<\Closure() : void> */
+	public function getContentChangedCallbacks() : ObjectSet{
+		return $this->contentChangedCallbacks;
+	}
+
+	private function onContentChange() : void{
+		foreach($this->contentChangedCallbacks as $callback){
+			$callback();
+		}
+	}
 }

src/network/mcpe/InventoryManager.php

@@ -37,19 +37,17 @@ use pocketmine\inventory\CreativeInventory;
 use pocketmine\inventory\Inventory;
 use pocketmine\inventory\transaction\action\SlotChangeAction;
 use pocketmine\inventory\transaction\InventoryTransaction;
-use pocketmine\item\Item;
+use pocketmine\network\mcpe\cache\CreativeInventoryCache;
 use pocketmine\network\mcpe\convert\TypeConverter;
 use pocketmine\network\mcpe\protocol\ClientboundPacket;
 use pocketmine\network\mcpe\protocol\ContainerClosePacket;
 use pocketmine\network\mcpe\protocol\ContainerOpenPacket;
 use pocketmine\network\mcpe\protocol\ContainerSetDataPacket;
-use pocketmine\network\mcpe\protocol\CreativeContentPacket;
 use pocketmine\network\mcpe\protocol\InventoryContentPacket;
 use pocketmine\network\mcpe\protocol\InventorySlotPacket;
 use pocketmine\network\mcpe\protocol\MobEquipmentPacket;
 use pocketmine\network\mcpe\protocol\types\BlockPosition;
 use pocketmine\network\mcpe\protocol\types\inventory\ContainerIds;
-use pocketmine\network\mcpe\protocol\types\inventory\CreativeContentEntry;
 use pocketmine\network\mcpe\protocol\types\inventory\ItemStack;
 use pocketmine\network\mcpe\protocol\types\inventory\ItemStackWrapper;
 use pocketmine\network\mcpe\protocol\types\inventory\NetworkInventoryAction;
@@ -599,16 +597,7 @@ class InventoryManager{
 	}
 
 	public function syncCreative() : void{
-		$typeConverter = TypeConverter::getInstance();
-
-		$entries = [];
-		if(!$this->player->isSpectator()){
-			//creative inventory may have holes if items were unregistered - ensure network IDs used are always consistent
-			foreach(CreativeInventory::getInstance()->getAll() as $k => $item){
-				$entries[] = new CreativeContentEntry($k, $typeConverter->coreItemStackToNet($item));
-			}
-		}
-		$this->session->sendDataPacket(CreativeContentPacket::create($entries));
+		$this->session->sendDataPacket(CreativeInventoryCache::getInstance()->getCache(CreativeInventory::getInstance()));
 	}
 
 	private function newItemStackId() : int{

src/network/mcpe/cache/CreativeInventoryCache.php

@@ -0,0 +1,69 @@
+<?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\network\mcpe\cache;
+
+use pocketmine\inventory\CreativeInventory;
+use pocketmine\network\mcpe\convert\TypeConverter;
+use pocketmine\network\mcpe\protocol\CreativeContentPacket;
+use pocketmine\network\mcpe\protocol\types\inventory\CreativeContentEntry;
+use pocketmine\utils\SingletonTrait;
+use function spl_object_id;
+
+final class CreativeInventoryCache{
+	use SingletonTrait;
+
+	/**
+	 * @var CreativeContentPacket[]
+	 * @phpstan-var array<int, CreativeContentPacket>
+	 */
+	private array $caches = [];
+
+	public function getCache(CreativeInventory $inventory) : CreativeContentPacket{
+		$id = spl_object_id($inventory);
+		if(!isset($this->caches[$id])){
+			$inventory->getDestructorCallbacks()->add(function() use ($id) : void{
+				unset($this->caches[$id]);
+			});
+			$inventory->getContentChangedCallbacks()->add(function() use ($id) : void{
+				unset($this->caches[$id]);
+			});
+			$this->caches[$id] = $this->buildCreativeInventoryCache($inventory);
+		}
+		return $this->caches[$id];
+	}
+
+	/**
+	 * Rebuild the cache for the given inventory.
+	 */
+	private function buildCreativeInventoryCache(CreativeInventory $inventory) : CreativeContentPacket{
+		$entries = [];
+		$typeConverter = TypeConverter::getInstance();
+		//creative inventory may have holes if items were unregistered - ensure network IDs used are always consistent
+		foreach($inventory->getAll() as $k => $item){
+			$entries[] = new CreativeContentEntry($k, $typeConverter->coreItemStackToNet($item));
+		}
+
+		return CreativeContentPacket::create($entries);
+	}
+}