Many many changes related to inventory transactions, fixed item dropping, fixed creative menu

src/pocketmine/inventory/transaction/SimpleInventoryTransaction.php

@@ -0,0 +1,173 @@
+<?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\transaction;
+
+use pocketmine\event\inventory\InventoryTransactionEvent;
+use pocketmine\inventory\Inventory;
+use pocketmine\inventory\transaction\InventoryTransaction;
+use pocketmine\inventory\transaction\action\InventoryAction;
+use pocketmine\inventory\transaction\action\SlotChangeAction;
+use pocketmine\item\Item;
+use pocketmine\Player;
+use pocketmine\Server;
+
+/**
+ * This InventoryTransaction only allows doing Transaction between one / two inventories
+ */
+class SimpleInventoryTransaction implements InventoryTransaction{
+	/** @var float */
+	private $creationTime;
+	protected $hasExecuted = false;
+	/** @var Player */
+	protected $source = null;
+
+	/** @var Inventory[] */
+	protected $inventories = [];
+
+	/** @var InventoryAction[] */
+	protected $actions = [];
+
+	/**
+	 * @param Player $source
+	 */
+	public function __construct(Player $source = null){
+		$this->creationTime = microtime(true);
+		$this->source = $source;
+	}
+
+	/**
+	 * @return Player
+	 */
+	public function getSource() : Player{
+		return $this->source;
+	}
+
+	public function getCreationTime() : float{
+		return $this->creationTime;
+	}
+
+	/**
+	 * @return Inventory[]
+	 */
+	public function getInventories() : array{
+		return $this->inventories;
+	}
+
+	/**
+	 * @return InventoryAction[]
+	 */
+	public function getActions() : array{
+		return $this->actions;
+	}
+
+	public function addAction(InventoryAction $action){
+		if(isset($this->actions[spl_object_hash($action)])){
+			return;
+		}
+
+		$this->actions[spl_object_hash($action)] = $action;
+		if($action instanceof SlotChangeAction){
+			$action->setInventoryFrom($this->source);
+			$this->inventories[spl_object_hash($action->getInventory())] = $action->getInventory();
+		}
+	}
+
+	/**
+	 * @param Item[] $needItems
+	 * @param Item[] $haveItems
+	 *
+	 * @return bool
+	 */
+	protected function matchItems(array &$needItems, array &$haveItems) : bool{
+		foreach($this->actions as $key => $action){
+			if($action->getTargetItem()->getId() !== Item::AIR){
+				$needItems[] = $action->getTargetItem();
+			}
+
+			if(!$action->isValid($this->source)){
+				return false;
+			}
+
+			if($action->getSourceItem()->getId() !== Item::AIR){
+				$haveItems[] = $action->getSourceItem();
+			}
+		}
+
+		foreach($needItems as $i => $needItem){
+			foreach($haveItems as $j => $haveItem){
+				if($needItem->equals($haveItem)){
+					$amount = min($needItem->getCount(), $haveItem->getCount());
+					$needItem->setCount($needItem->getCount() - $amount);
+					$haveItem->setCount($haveItem->getCount() - $amount);
+					if($haveItem->getCount() === 0){
+						unset($haveItems[$j]);
+					}
+					if($needItem->getCount() === 0){
+						unset($needItems[$i]);
+						break;
+					}
+				}
+			}
+		}
+
+		return true;
+	}
+
+	public function canExecute() : bool{
+		$haveItems = [];
+		$needItems = [];
+
+		return $this->matchItems($needItems, $haveItems) and count($this->actions) > 0 and count($haveItems) === 0 and count($needItems) === 0;
+	}
+
+	/**
+	 * @return bool
+	 */
+	public function execute() : bool{
+		if($this->hasExecuted() or !$this->canExecute()){
+			return false;
+		}
+
+		Server::getInstance()->getPluginManager()->callEvent($ev = new InventoryTransactionEvent($this));
+		if($ev->isCancelled()){
+			return false;
+		}
+
+		foreach($this->actions as $action){
+			if($action->execute($this->source)){
+				$action->onExecuteSuccess($this->source);
+			}else{
+				$action->onExecuteFail($this->source);
+			}
+		}
+
+		$this->hasExecuted = true;
+
+		return true;
+	}
+
+	public function hasExecuted() : bool{
+		return $this->hasExecuted;
+	}
+}