PocketMine-MP/src/data/bedrock/block/convert/BlockObjectToStateSerializer.php

<?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\data\bedrock\block\convert;

use pocketmine\block\Block;
use pocketmine\block\RuntimeBlockStateRegistry;
use pocketmine\block\Slab;
use pocketmine\block\Stair;
use pocketmine\block\Wood;
use pocketmine\data\bedrock\block\BlockStateData;
use pocketmine\data\bedrock\block\BlockStateSerializeException;
use pocketmine\data\bedrock\block\BlockStateSerializer;
use pocketmine\data\bedrock\block\BlockTypeNames as Ids;
use pocketmine\data\bedrock\block\convert\BlockStateSerializerHelper as Helper;
use pocketmine\data\bedrock\block\convert\BlockStateWriter as Writer;
use function get_class;

final class BlockObjectToStateSerializer implements BlockStateSerializer{
	/**
	 * These callables actually accept Block, but for the sake of type completeness, it has to be never, since we can't
	 * describe the bottom type of a type hierarchy only containing Block.
	 *
	 * @var (\Closure|BlockStateData)[]
	 * @phpstan-var array<int, \Closure(never) : (Writer|BlockStateData)|BlockStateData>
	 */
	private array $serializers = [];

	/**
	 * @var BlockStateData[]
	 * @phpstan-var array<int, BlockStateData>
	 */
	private array $cache = [];

	public function serialize(int $stateId) : BlockStateData{
		//TODO: singleton usage not ideal
		//TODO: we may want to deduplicate cache entries to avoid wasting memory
		return $this->cache[$stateId] ??= $this->serializeBlock(RuntimeBlockStateRegistry::getInstance()->fromStateId($stateId));
	}

	public function isRegistered(Block $block) : bool{
		return isset($this->serializers[$block->getTypeId()]);
	}

	/**
	 * @phpstan-template TBlockType of Block
	 * @phpstan-param TBlockType $block
	 * @phpstan-param \Closure(TBlockType) : (Writer|BlockStateData)|Writer|BlockStateData $serializer
	 */
	public function map(Block $block, \Closure|Writer|BlockStateData $serializer) : void{
		if(isset($this->serializers[$block->getTypeId()])){
			throw new \InvalidArgumentException("Block type ID " . $block->getTypeId() . " (" . $block->getName() . ") already has a serializer registered");
		}
		//writer accepted for convenience only
		$this->serializers[$block->getTypeId()] = $serializer instanceof Writer ? $serializer->getBlockStateData() : $serializer;
	}

	/**
	 * @deprecated
	 */
	public function mapSimple(Block $block, string $id) : void{
		$this->map($block, BlockStateData::current($id, []));
	}

	/**
	 * @deprecated
	 */
	public function mapSlab(Slab $block, string $singleId, string $doubleId) : void{
		$this->map($block, fn(Slab $block) => Helper::encodeSlab($block, $singleId, $doubleId));
	}

	/**
	 * @deprecated
	 */
	public function mapStairs(Stair $block, string $id) : void{
		$this->map($block, fn(Stair $block) => Helper::encodeStairs($block, Writer::create($id)));
	}

	/**
	 * @deprecated
	 */
	public function mapLog(Wood $block, string $unstrippedId, string $strippedId) : void{
		$this->map($block, fn(Wood $block) => Helper::encodeLog($block, $unstrippedId, $strippedId));
	}

	/**
	 * @phpstan-template TBlockType of Block
	 * @phpstan-param TBlockType $blockState
	 *
	 * @throws BlockStateSerializeException
	 */
	public function serializeBlock(Block $blockState) : BlockStateData{
		$typeId = $blockState->getTypeId();

		$locatedSerializer = $this->serializers[$typeId] ?? null;
		if($locatedSerializer === null){
			throw new BlockStateSerializeException("No serializer registered for " . get_class($blockState) . " with type ID $typeId");
		}

		if($locatedSerializer instanceof BlockStateData){ //static data, not dependent on state
			return $locatedSerializer;
		}

		/**
		 * TODO: there is no guarantee that this type actually matches that of $blockState - a plugin may have stolen
		 * the type ID of the block (which never makes sense, even in a world where overriding block types is a thing).
		 * In the future we'll need some way to guarantee that type IDs are never reused (perhaps spl_object_id()?)
		 *
		 * @var \Closure $locatedSerializer
		 * @phpstan-var \Closure(TBlockType) : (Writer|BlockStateData) $locatedSerializer
		 */
		$result = $locatedSerializer($blockState);

		return $result instanceof Writer ? $result->getBlockStateData() : $result;
	}
}