RegionWorldProvider.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\world\format\io\region;
 
use pocketmine\nbt\NBT;
use pocketmine\nbt\tag\ByteArrayTag;
use pocketmine\nbt\tag\CompoundTag;
use pocketmine\nbt\tag\ListTag;
use pocketmine\world\format\io\BaseWorldProvider;
use pocketmine\world\format\io\data\JavaWorldData;
use pocketmine\world\format\io\exception\CorruptedChunkException;
use pocketmine\world\format\io\LoadedChunkData;
use pocketmine\world\format\io\WorldData;
use Symfony\Component\Filesystem\Path;
use function file_exists;
use function is_dir;
use function morton2d_encode;
use function rename;
use function scandir;
use function strlen;
use function strrpos;
use function substr;
use function time;
use const SCANDIR_SORT_NONE;
 
abstract class RegionWorldProvider extends BaseWorldProvider{
 
    abstract protected static function getRegionFileExtension() : string;
 
    abstract protected static function getPcWorldFormatVersion() : int;
 
    public static function isValid(string $path) : bool{
        if(file_exists(Path::join($path, "level.dat")) && is_dir($regionPath = Path::join($path, "region"))){
            $files = scandir($regionPath, SCANDIR_SORT_NONE);
            if($files === false){
                //we can't tell the type if we don't have read perms
                return false;
            }
            foreach($files as $file){
                $extPos = strrpos($file, ".");
                if($extPos !== false && substr($file, $extPos + 1) === static::getRegionFileExtension()){
                    //we don't care if other region types exist, we only care if this format is possible
                    return true;
                }
            }
        }
 
        return false;
    }
 
    protected array $regions = [];
 
    protected function loadLevelData() : WorldData{
        return new JavaWorldData(Path::join($this->getPath(), "level.dat"));
    }
 
    public function doGarbageCollection() : void{
        $limit = time() - 300;
        foreach($this->regions as $index => $region){
            if($region->lastUsed <= $limit){
                $region->close();
                unset($this->regions[$index]);
            }
        }
    }
 
    public static function getRegionIndex(int $chunkX, int $chunkZ, &$regionX, &$regionZ) : void{
        $regionX = $chunkX >> 5;
        $regionZ = $chunkZ >> 5;
    }
 
    protected function getRegion(int $regionX, int $regionZ) : ?RegionLoader{
        return $this->regions[morton2d_encode($regionX, $regionZ)] ?? null;
    }
 
    protected function pathToRegion(int $regionX, int $regionZ) : string{
        return Path::join($this->path, "region", "r.$regionX.$regionZ." . static::getRegionFileExtension());
    }
 
    protected function loadRegion(int $regionX, int $regionZ) : RegionLoader{
        if(!isset($this->regions[$index = morton2d_encode($regionX, $regionZ)])){
            $path = $this->pathToRegion($regionX, $regionZ);
 
            try{
                $this->regions[$index] = RegionLoader::loadExisting($path);
            }catch(CorruptedRegionException $e){
                $this->logger->error("Corrupted region file detected: " . $e->getMessage());
 
                $backupPath = $path . ".bak." . time();
                rename($path, $backupPath);
                $this->logger->error("Corrupted region file has been backed up to " . $backupPath);
 
                $this->regions[$index] = RegionLoader::createNew($path);
            }
        }
        return $this->regions[$index];
    }
 
    protected function unloadRegion(int $regionX, int $regionZ) : void{
        if(isset($this->regions[$hash = morton2d_encode($regionX, $regionZ)])){
            $this->regions[$hash]->close();
            unset($this->regions[$hash]);
        }
    }
 
    public function close() : void{
        foreach($this->regions as $index => $region){
            $region->close();
            unset($this->regions[$index]);
        }
    }
 
    abstract protected function deserializeChunk(string $data, \Logger $logger) : ?LoadedChunkData;
 
    protected static function getCompoundList(string $context, ListTag $list) : array{
        if($list->count() === 0){ //empty lists might have wrong types, we don't care
            return [];
        }
        if($list->getTagType() !== NBT::TAG_Compound){
            throw new CorruptedChunkException("Expected TAG_List<TAG_Compound> for '$context'");
        }
        $result = [];
        foreach($list as $tag){
            if(!($tag instanceof CompoundTag)){
                //this should never happen, but it's still possible due to lack of native type safety
                throw new CorruptedChunkException("Expected TAG_List<TAG_Compound> for '$context'");
            }
            $result[] = $tag;
        }
        return $result;
    }
 
    protected static function readFixedSizeByteArray(CompoundTag $chunk, string $tagName, int $length) : string{
        $tag = $chunk->getTag($tagName);
        if(!($tag instanceof ByteArrayTag)){
            if($tag === null){
                throw new CorruptedChunkException("'$tagName' key is missing from chunk NBT");
            }
            throw new CorruptedChunkException("Expected TAG_ByteArray for '$tagName'");
        }
        $data = $tag->getValue();
        if(strlen($data) !== $length){
            throw new CorruptedChunkException("Expected '$tagName' payload to have exactly $length bytes, but have " . strlen($data));
        }
        return $data;
    }
 
    public function loadChunk(int $chunkX, int $chunkZ) : ?LoadedChunkData{
        $regionX = $regionZ = null;
        self::getRegionIndex($chunkX, $chunkZ, $regionX, $regionZ);
 
        if(!file_exists($this->pathToRegion($regionX, $regionZ))){
            return null;
        }
 
        $chunkData = $this->loadRegion($regionX, $regionZ)->readChunk($chunkX & 0x1f, $chunkZ & 0x1f);
        if($chunkData !== null){
            return $this->deserializeChunk($chunkData, new \PrefixedLogger($this->logger, "Loading chunk x=$chunkX z=$chunkZ"));
        }
 
        return null;
    }
 
    private function createRegionIterator() : \RegexIterator{
        return new \RegexIterator(
            new \FilesystemIterator(
                Path::join($this->path, 'region'),
                \FilesystemIterator::CURRENT_AS_PATHNAME | \FilesystemIterator::SKIP_DOTS | \FilesystemIterator::UNIX_PATHS
            ),
            '/\/r\.(-?\d+)\.(-?\d+)\.' . static::getRegionFileExtension() . '$/',
            \RegexIterator::GET_MATCH
        );
    }
 
    public function getAllChunks(bool $skipCorrupted = false, ?\Logger $logger = null) : \Generator{
        $iterator = $this->createRegionIterator();
 
        foreach($iterator as $region){
            $regionX = ((int) $region[1]);
            $regionZ = ((int) $region[2]);
            $rX = $regionX << 5;
            $rZ = $regionZ << 5;
 
            for($chunkX = $rX; $chunkX < $rX + 32; ++$chunkX){
                for($chunkZ = $rZ; $chunkZ < $rZ + 32; ++$chunkZ){
                    try{
                        $chunk = $this->loadChunk($chunkX, $chunkZ);
                        if($chunk !== null){
                            yield [$chunkX, $chunkZ] => $chunk;
                        }
                    }catch(CorruptedChunkException $e){
                        if(!$skipCorrupted){
                            throw $e;
                        }
                        if($logger !== null){
                            $logger->error("Skipped corrupted chunk $chunkX $chunkZ (" . $e->getMessage() . ")");
                        }
                    }
                }
            }
 
            $this->unloadRegion($regionX, $regionZ);
        }
    }
 
    public function calculateChunkCount() : int{
        $count = 0;
        foreach($this->createRegionIterator() as $region){
            $regionX = ((int) $region[1]);
            $regionZ = ((int) $region[2]);
            $count += $this->loadRegion($regionX, $regionZ)->calculateChunkCount();
            $this->unloadRegion($regionX, $regionZ);
        }
        return $count;
    }
}