Added StructureGrowEvent (#4354)

This event is currently fired for tree and bamboo growth. Its intended use is for any plant growth that affects multiple blocks at once.

TODO: We could explore using this for cacti and sugarcane?

src/block/Bamboo.php

@@ -24,6 +24,7 @@ declare(strict_types=1);
 namespace pocketmine\block;
 
 use pocketmine\block\utils\BlockDataSerializer;
+use pocketmine\event\block\StructureGrowEvent;
 use pocketmine\item\Bamboo as ItemBamboo;
 use pocketmine\item\Fertilizer;
 use pocketmine\item\Item;
@@ -210,6 +211,13 @@ class Bamboo extends Transparent{
 		foreach($newBlocks as $idx => $newBlock){
 			$tx->addBlock($this->position->subtract(0, $idx - $growAmount, 0), $newBlock);
 		}
+
+		$ev = new StructureGrowEvent($this, $tx);
+		$ev->call();
+		if($ev->isCancelled()){
+			return false;
+		}
+
 		return $tx->apply();
 	}
 

src/block/BambooSapling.php

@@ -23,6 +23,7 @@ declare(strict_types=1);
 
 namespace pocketmine\block;
 
+use pocketmine\event\block\StructureGrowEvent;
 use pocketmine\item\Bamboo as ItemBamboo;
 use pocketmine\item\Fertilizer;
 use pocketmine\item\Item;
@@ -96,6 +97,13 @@ final class BambooSapling extends Flowable{
 		$bamboo = VanillaBlocks::BAMBOO();
 		$tx->addBlock($this->position, $bamboo)
 			->addBlock($this->position->up(), (clone $bamboo)->setLeafSize(Bamboo::SMALL_LEAVES));
+
+		$ev = new StructureGrowEvent($this, $tx);
+		$ev->call();
+		if($ev->isCancelled()){
+			return false;
+		}
+
 		return $tx->apply();
 	}
 

src/block/Sapling.php

@@ -76,7 +76,7 @@ class Sapling extends Flowable{
 
 	public function onInteract(Item $item, int $face, Vector3 $clickVector, ?Player $player = null) : bool{
 		if($item instanceof Fertilizer){
-			Tree::growTree($this->position->getWorld(), $this->position->x, $this->position->y, $this->position->z, new Random(mt_rand()), $this->treeType);
+			Tree::growTree($this->position->getWorld(), $this->position->x, $this->position->y, $this->position->z, new Random(mt_rand()), $this->treeType, true);
 
 			$item->pop();
 
@@ -99,7 +99,7 @@ class Sapling extends Flowable{
 	public function onRandomTick() : void{
 		if($this->position->getWorld()->getFullLightAt($this->position->x, $this->position->y, $this->position->z) >= 8 and mt_rand(1, 7) === 1){
 			if($this->ready){
-				Tree::growTree($this->position->getWorld(), $this->position->x, $this->position->y, $this->position->z, new Random(mt_rand()), $this->treeType);
+				Tree::growTree($this->position->getWorld(), $this->position->x, $this->position->y, $this->position->z, new Random(mt_rand()), $this->treeType, true);
 			}else{
 				$this->ready = true;
 				$this->position->getWorld()->setBlock($this->position, $this);

src/event/block/StructureGrowEvent.php

@@ -0,0 +1,29 @@
+<?php
+
+declare(strict_types=1);
+
+namespace pocketmine\event\block;
+
+use pocketmine\block\Block;
+use pocketmine\event\Cancellable;
+use pocketmine\event\CancellableTrait;
+use pocketmine\world\BlockTransaction;
+
+/**
+ * Called when structures such as Saplings or Bamboo grow.
+ * These types of plants tend to change multiple blocks at once upon growing.
+ */
+class StructureGrowEvent extends BlockEvent implements Cancellable{
+	use CancellableTrait;
+
+	private BlockTransaction $transaction;
+
+	public function __construct(Block $block, BlockTransaction $transaction){
+		parent::__construct($block);
+		$this->transaction = $transaction;
+	}
+
+	public function getTransaction() : BlockTransaction{
+		return $this->transaction;
+	}
+}

src/world/generator/object/BirchTree.php

@@ -36,11 +36,11 @@ class BirchTree extends Tree{
 		$this->superBirch = $superBirch;
 	}
 
-	public function placeObject(ChunkManager $world, int $x, int $y, int $z, Random $random) : void{
+	public function placeObject(ChunkManager $world, int $x, int $y, int $z, Random $random, bool $callEvent = false) : void{
 		$this->treeHeight = $random->nextBoundedInt(3) + 5;
 		if($this->superBirch){
 			$this->treeHeight += 5;
 		}
-		parent::placeObject($world, $x, $y, $z, $random);
+		parent::placeObject($world, $x, $y, $z, $random, $callEvent);
 	}
 }

src/world/generator/object/OakTree.php

@@ -33,8 +33,8 @@ class OakTree extends Tree{
 		parent::__construct(VanillaBlocks::OAK_LOG(), VanillaBlocks::OAK_LEAVES());
 	}
 
-	public function placeObject(ChunkManager $world, int $x, int $y, int $z, Random $random) : void{
+	public function placeObject(ChunkManager $world, int $x, int $y, int $z, Random $random, bool $callEvent = false) : void{
 		$this->treeHeight = $random->nextBoundedInt(3) + 4;
-		parent::placeObject($world, $x, $y, $z, $random);
+		parent::placeObject($world, $x, $y, $z, $random, $callEvent);
 	}
 }

src/world/generator/object/SpruceTree.php

@@ -39,9 +39,9 @@ class SpruceTree extends Tree{
 		return $this->treeHeight - $random->nextBoundedInt(3);
 	}
 
-	public function placeObject(ChunkManager $world, int $x, int $y, int $z, Random $random) : void{
+	public function placeObject(ChunkManager $world, int $x, int $y, int $z, Random $random, bool $callEvent = false) : void{
 		$this->treeHeight = $random->nextBoundedInt(4) + 6;
-		parent::placeObject($world, $x, $y, $z, $random);
+		parent::placeObject($world, $x, $y, $z, $random, $callEvent);
 	}
 
 	protected function placeCanopy(int $x, int $y, int $z, Random $random, BlockTransaction $transaction) : void{

src/world/generator/object/Tree.php

@@ -28,6 +28,7 @@ use pocketmine\block\Leaves;
 use pocketmine\block\Sapling;
 use pocketmine\block\utils\TreeType;
 use pocketmine\block\VanillaBlocks;
+use pocketmine\event\block\StructureGrowEvent;
 use pocketmine\utils\Random;
 use pocketmine\world\BlockTransaction;
 use pocketmine\world\ChunkManager;
@@ -51,10 +52,11 @@ abstract class Tree{
 
 	/**
 	 * @param TreeType|null $type default oak
+	 * @param bool          $callEvent set this parameter to true to allow the calling of the BlockSproutEvent when the tree grows
 	 *
 	 * @throws \InvalidArgumentException
 	 */
-	public static function growTree(ChunkManager $world, int $x, int $y, int $z, Random $random, ?TreeType $type = null) : void{
+	public static function growTree(ChunkManager $world, int $x, int $y, int $z, Random $random, ?TreeType $type = null, bool $callEvent = false) : void{
 		/** @var null|Tree $tree */
 		$tree = null;
 		$type = $type ?? TreeType::OAK();
@@ -78,7 +80,7 @@ abstract class Tree{
 		}
 
 		if($tree !== null and $tree->canPlaceObject($world, $x, $y, $z, $random)){
-			$tree->placeObject($world, $x, $y, $z, $random);
+			$tree->placeObject($world, $x, $y, $z, $random, $callEvent);
 		}
 	}
 
@@ -100,11 +102,19 @@ abstract class Tree{
 		return true;
 	}
 
-	public function placeObject(ChunkManager $world, int $x, int $y, int $z, Random $random) : void{
+	public function placeObject(ChunkManager $world, int $x, int $y, int $z, Random $random, bool $callEvent = false) : void{
 		$transaction = new BlockTransaction($world);
 		$this->placeTrunk($x, $y, $z, $random, $this->generateChunkHeight($random), $transaction);
 		$this->placeCanopy($x, $y, $z, $random, $transaction);
 
+		if($callEvent){
+			$ev = new StructureGrowEvent($world->getBlockAt($x, $y, $z), $transaction);
+			$ev->call();
+			if($ev->isCancelled()){
+				return;
+			}
+		}
+
 		$transaction->apply(); //TODO: handle return value on failure
 	}