From cf5e31c61911a2a8d1d1a239df56aab00d5de17e Mon Sep 17 00:00:00 2001
From: "Dylan K. Taylor" <odigiman@gmail.com>
Date: Wed, 1 Jul 2020 14:08:28 +0100
Subject: [PATCH] InventoryTransaction::execute() now throws exceptions instead
 of returning true/false

---
 .../transaction/InventoryTransaction.php      | 28 ++++-------------
 .../TransactionCancelledException.php         | 31 +++++++++++++++++++
 .../transaction/TransactionException.php      | 31 +++++++++++++++++++
 .../TransactionValidationException.php        |  5 ++-
 .../mcpe/handler/InGamePacketHandler.php      | 14 +++++++--
 5 files changed, 83 insertions(+), 26 deletions(-)
 create mode 100644 src/inventory/transaction/TransactionCancelledException.php
 create mode 100644 src/inventory/transaction/TransactionException.php

diff --git a/src/inventory/transaction/InventoryTransaction.php b/src/inventory/transaction/InventoryTransaction.php
index d6680c284e..e7b4a6d3fc 100644
--- a/src/inventory/transaction/InventoryTransaction.php
+++ b/src/inventory/transaction/InventoryTransaction.php
@@ -269,12 +269,6 @@ class InventoryTransaction{
 		}
 	}
 
-	protected function sendInventories() : void{
-		foreach($this->inventories as $inventory){
-			$this->source->getNetworkSession()->getInvManager()->syncContents($inventory);
-		}
-	}
-
 	protected function callExecuteEvent() : bool{
 		$ev = new InventoryTransactionEvent($this);
 		$ev->call();
@@ -284,32 +278,24 @@ class InventoryTransaction{
 	/**
 	 * Executes the group of actions, returning whether the transaction executed successfully or not.
 	 *
-	 * @throws TransactionValidationException
+	 * @throws TransactionException
 	 */
-	public function execute() : bool{
+	public function execute() : void{
 		if($this->hasExecuted()){
-			$this->sendInventories();
-			return false;
+			throw new TransactionValidationException("Transaction has already been executed");
 		}
 
 		$this->shuffleActions();
 
-		try{
-			$this->validate();
-		}catch(TransactionValidationException $e){
-			$this->sendInventories();
-			throw $e;
-		}
+		$this->validate();
 
 		if(!$this->callExecuteEvent()){
-			$this->sendInventories();
-			return false;
+			throw new TransactionCancelledException("Transaction event cancelled");
 		}
 
 		foreach($this->actions as $action){
 			if(!$action->onPreExecute($this->source)){
-				$this->sendInventories();
-				return false;
+				throw new TransactionCancelledException("One of the actions in this transaction was cancelled");
 			}
 		}
 
@@ -318,8 +304,6 @@ class InventoryTransaction{
 		}
 
 		$this->hasExecuted = true;
-
-		return true;
 	}
 
 	public function hasExecuted() : bool{
diff --git a/src/inventory/transaction/TransactionCancelledException.php b/src/inventory/transaction/TransactionCancelledException.php
new file mode 100644
index 0000000000..7db33ed3a4
--- /dev/null
+++ b/src/inventory/transaction/TransactionCancelledException.php
@@ -0,0 +1,31 @@
+<?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;
+
+/**
+ * Thrown when an inventory transaction is valid, but can't proceed due to other factors (e.g. a plugin intervened).
+ */
+final class TransactionCancelledException extends TransactionException{
+
+}
diff --git a/src/inventory/transaction/TransactionException.php b/src/inventory/transaction/TransactionException.php
new file mode 100644
index 0000000000..daa173e089
--- /dev/null
+++ b/src/inventory/transaction/TransactionException.php
@@ -0,0 +1,31 @@
+<?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;
+
+/**
+ * Thrown when a transaction fails to execute for any reason.
+ */
+abstract class TransactionException extends \RuntimeException{
+
+}
diff --git a/src/inventory/transaction/TransactionValidationException.php b/src/inventory/transaction/TransactionValidationException.php
index f306075a20..7b72f545fd 100644
--- a/src/inventory/transaction/TransactionValidationException.php
+++ b/src/inventory/transaction/TransactionValidationException.php
@@ -23,6 +23,9 @@ declare(strict_types=1);
 
 namespace pocketmine\inventory\transaction;
 
-class TransactionValidationException extends \RuntimeException{
+/**
+ * Thrown when a transaction cannot proceed due to preconditions not being met (e.g. transaction doesn't balance).
+ */
+class TransactionValidationException extends TransactionException{
 
 }
diff --git a/src/network/mcpe/handler/InGamePacketHandler.php b/src/network/mcpe/handler/InGamePacketHandler.php
index 0906e08a94..6cf3d0ee35 100644
--- a/src/network/mcpe/handler/InGamePacketHandler.php
+++ b/src/network/mcpe/handler/InGamePacketHandler.php
@@ -33,7 +33,7 @@ use pocketmine\event\player\PlayerEditBookEvent;
 use pocketmine\inventory\transaction\action\InventoryAction;
 use pocketmine\inventory\transaction\CraftingTransaction;
 use pocketmine\inventory\transaction\InventoryTransaction;
-use pocketmine\inventory\transaction\TransactionValidationException;
+use pocketmine\inventory\transaction\TransactionException;
 use pocketmine\item\VanillaItems;
 use pocketmine\item\WritableBook;
 use pocketmine\item\WrittenBook;
@@ -247,9 +247,13 @@ class InGamePacketHandler extends PacketHandler{
 				try{
 					$this->session->getInvManager()->onTransactionStart($this->craftingTransaction);
 					$this->craftingTransaction->execute();
-				}catch(TransactionValidationException $e){
+				}catch(TransactionException $e){
 					$this->session->getLogger()->debug("Failed to execute crafting transaction: " . $e->getMessage());
 
+					//TODO: only sync slots that the client tried to change
+					foreach($this->craftingTransaction->getInventories() as $inventory){
+						$this->session->getInvManager()->syncContents($inventory);
+					}
 					/*
 					 * TODO: HACK!
 					 * we can't resend the contents of the crafting window, so we force the client to close it instead.
@@ -280,11 +284,15 @@ class InGamePacketHandler extends PacketHandler{
 			$this->session->getInvManager()->onTransactionStart($transaction);
 			try{
 				$transaction->execute();
-			}catch(TransactionValidationException $e){
+			}catch(TransactionException $e){
 				$logger = $this->session->getLogger();
 				$logger->debug("Failed to execute inventory transaction: " . $e->getMessage());
 				$logger->debug("Actions: " . json_encode($data->getActions()));
 
+				foreach($transaction->getInventories() as $inventory){
+					$this->session->getInvManager()->syncContents($inventory);
+				}
+
 				return false;
 			}
 		}