348 lines
10 KiB
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\level\format\io\region;
use pocketmine\level\format\ChunkException;
use pocketmine\level\format\io\exception\CorruptedChunkException;
use pocketmine\utils\Binary;
use pocketmine\utils\MainLogger;
use function ceil;
use function chr;
use function fclose;
use function feof;
use function file_exists;
use function filesize;
use function fopen;
use function fread;
use function fseek;
use function ftruncate;
use function fwrite;
use function is_resource;
use function max;
use function ord;
use function pack;
use function str_pad;
use function stream_set_read_buffer;
use function stream_set_write_buffer;
use function strlen;
use function substr;
use function time;
use function touch;
use function unpack;
use const STR_PAD_RIGHT;
class RegionLoader{
public const VERSION = 1;
public const COMPRESSION_GZIP = 1;
public const COMPRESSION_ZLIB = 2;
public const MAX_SECTOR_LENGTH = 255 << 12; //255 sectors (~0.996 MiB)
public const REGION_HEADER_LENGTH = 8192; //4096 location table + 4096 timestamps
public static $COMPRESSION_LEVEL = 7;
/** @var int */
protected $x;
/** @var int */
protected $z;
/** @var string */
protected $filePath;
/** @var resource */
protected $filePointer;
/** @var int */
protected $lastSector;
/** @var RegionLocationTableEntry[] */
protected $locationTable = [];
/** @var int */
public $lastUsed = 0;
public function __construct(string $filePath, int $regionX, int $regionZ){
$this->x = $regionX;
$this->z = $regionZ;
$this->filePath = $filePath;
}
/**
* @throws CorruptedRegionException
*/
public function open(){
$exists = file_exists($this->filePath);
if(!$exists){
touch($this->filePath);
}elseif(filesize($this->filePath) % 4096 !== 0){
throw new CorruptedRegionException("Region file should be padded to a multiple of 4KiB");
}
$this->filePointer = fopen($this->filePath, "r+b");
stream_set_read_buffer($this->filePointer, 1024 * 16); //16KB
stream_set_write_buffer($this->filePointer, 1024 * 16); //16KB
if(!$exists){
$this->createBlank();
}else{
$this->loadLocationTable();
}
$this->lastUsed = time();
}
public function __destruct(){
if(is_resource($this->filePointer)){
$this->writeLocationTable();
fclose($this->filePointer);
}
}
protected function isChunkGenerated(int $index) : bool{
return !$this->locationTable[$index]->isNull();
}
/**
* @param int $x
* @param int $z
*
* @return null|string
* @throws \InvalidArgumentException if invalid coordinates are given
* @throws CorruptedChunkException if chunk corruption is detected
*/
public function readChunk(int $x, int $z) : ?string{
$index = self::getChunkOffset($x, $z);
$this->lastUsed = time();
if(!$this->isChunkGenerated($index)){
return null;
}
fseek($this->filePointer, $this->locationTable[$index]->getFirstSector() << 12);
$prefix = fread($this->filePointer, 4);
if($prefix === false or strlen($prefix) !== 4){
throw new CorruptedChunkException("Corrupted chunk header detected (unexpected end of file reading length prefix)");
}
$length = Binary::readInt($prefix);
if($length <= 0){ //TODO: if we reached here, the locationTable probably needs updating
return null;
}
if($length > self::MAX_SECTOR_LENGTH){ //corrupted
throw new CorruptedChunkException("Length for chunk x=$x,z=$z ($length) is larger than maximum " . self::MAX_SECTOR_LENGTH);
}
if($length > ($this->locationTable[$index]->getSectorCount() << 12)){ //Invalid chunk, bigger than defined number of sectors
MainLogger::getLogger()->error("Chunk x=$x,z=$z length mismatch (expected " . ($this->locationTable[$index]->getSectorCount() << 12) . " sectors, got $length sectors)");
$old = $this->locationTable[$index];
$this->locationTable[$index] = new RegionLocationTableEntry($old->getFirstSector(), $length >> 12, time());
$this->writeLocationIndex($index);
}
$chunkData = fread($this->filePointer, $length);
if($chunkData === false or strlen($chunkData) !== $length){
throw new CorruptedChunkException("Corrupted chunk detected (unexpected end of file reading chunk data)");
}
$compression = ord($chunkData[0]);
if($compression !== self::COMPRESSION_ZLIB and $compression !== self::COMPRESSION_GZIP){
throw new CorruptedChunkException("Invalid compression type (got $compression, expected " . self::COMPRESSION_ZLIB . " or " . self::COMPRESSION_GZIP . ")");
}
return substr($chunkData, 1);
}
/**
* @param int $x
* @param int $z
*
* @return bool
* @throws \InvalidArgumentException
*/
public function chunkExists(int $x, int $z) : bool{
return $this->isChunkGenerated(self::getChunkOffset($x, $z));
}
/**
* @param int $x
* @param int $z
* @param string $chunkData
*
* @throws ChunkException
* @throws \InvalidArgumentException
*/
public function writeChunk(int $x, int $z, string $chunkData){
$this->lastUsed = time();
$length = strlen($chunkData) + 1;
if($length + 4 > self::MAX_SECTOR_LENGTH){
throw new ChunkException("Chunk is too big! " . ($length + 4) . " > " . self::MAX_SECTOR_LENGTH);
}
$newSize = (int) ceil(($length + 4) / 4096);
$index = self::getChunkOffset($x, $z);
$offset = $this->locationTable[$index]->getFirstSector();
if($this->locationTable[$index]->getSectorCount() < $newSize){
$offset = $this->lastSector + 1;
}
$this->locationTable[$index] = new RegionLocationTableEntry($offset, $newSize, time());
$this->lastSector = max($this->lastSector, $this->locationTable[$index]->getLastSector());
fseek($this->filePointer, $offset << 12);
fwrite($this->filePointer, str_pad(Binary::writeInt($length) . chr(self::COMPRESSION_ZLIB) . $chunkData, $newSize << 12, "\x00", STR_PAD_RIGHT));
$this->writeLocationIndex($index);
}
/**
* @param int $x
* @param int $z
*
* @throws \InvalidArgumentException
*/
public function removeChunk(int $x, int $z){
$index = self::getChunkOffset($x, $z);
$this->locationTable[$index] = new RegionLocationTableEntry(0, 0, 0);
}
/**
* @param int $x
* @param int $z
*
* @return int
* @throws \InvalidArgumentException
*/
protected static function getChunkOffset(int $x, int $z) : int{
if($x < 0 or $x > 31 or $z < 0 or $z > 31){
throw new \InvalidArgumentException("Invalid chunk position in region, expected x/z in range 0-31, got x=$x, z=$z");
}
return $x | ($z << 5);
}
/**
* @param int $offset
* @param int &$x
* @param int &$z
*/
protected static function getChunkCoords(int $offset, ?int &$x, ?int &$z) : void{
$x = $offset & 0x1f;
$z = ($offset >> 5) & 0x1f;
}
/**
* Writes the region header and closes the file
*
* @param bool $writeHeader
*/
public function close(bool $writeHeader = true){
if(is_resource($this->filePointer)){
if($writeHeader){
$this->writeLocationTable();
}
fclose($this->filePointer);
}
}
/**
* @throws CorruptedRegionException
*/
protected function loadLocationTable(){
fseek($this->filePointer, 0);
$this->lastSector = 1;
$headerRaw = fread($this->filePointer, self::REGION_HEADER_LENGTH);
if(($len = strlen($headerRaw)) !== self::REGION_HEADER_LENGTH){
throw new CorruptedRegionException("Invalid region file header, expected " . self::REGION_HEADER_LENGTH . " bytes, got " . $len . " bytes");
}
$data = unpack("N*", $headerRaw);
/** @var int[] $usedOffsets */
$usedOffsets = [];
for($i = 0; $i < 1024; ++$i){
$index = $data[$i + 1];
$offset = $index >> 8;
$timestamp = $data[$i + 1025];
if($offset !== 0){
self::getChunkCoords($i, $x, $z);
$fileOffset = $offset << 12;
fseek($this->filePointer, $fileOffset);
if(feof($this->filePointer)){
throw new CorruptedRegionException("Region file location offset x=$x,z=$z points to invalid file location $fileOffset");
}elseif(isset($usedOffsets[$offset])){
self::getChunkCoords($usedOffsets[$offset], $existingX, $existingZ);
throw new CorruptedRegionException("Found two chunk offsets (chunk1: x=$existingX,z=$existingZ, chunk2: x=$x,z=$z) pointing to the file location $fileOffset");
}else{
$usedOffsets[$offset] = $i;
}
}
$this->locationTable[$i] = new RegionLocationTableEntry($offset, $index & 0xff, $timestamp);
$this->lastSector = max($this->lastSector, $this->locationTable[$i]->getLastSector());
}
fseek($this->filePointer, 0);
}
private function writeLocationTable(){
$write = [];
for($i = 0; $i < 1024; ++$i){
$write[] = (($this->locationTable[$i]->getFirstSector() << 8) | $this->locationTable[$i]->getSectorCount());
}
for($i = 0; $i < 1024; ++$i){
$write[] = $this->locationTable[$i]->getTimestamp();
}
fseek($this->filePointer, 0);
fwrite($this->filePointer, pack("N*", ...$write), 4096 * 2);
}
protected function writeLocationIndex($index){
fseek($this->filePointer, $index << 2);
fwrite($this->filePointer, Binary::writeInt(($this->locationTable[$index]->getFirstSector() << 8) | $this->locationTable[$index]->getSectorCount()), 4);
fseek($this->filePointer, 4096 + ($index << 2));
fwrite($this->filePointer, Binary::writeInt($this->locationTable[$index]->getTimestamp()), 4);
}
protected function createBlank(){
fseek($this->filePointer, 0);
ftruncate($this->filePointer, 8192); // this fills the file with the null byte
$this->lastSector = 1;
for($i = 0; $i < 1024; ++$i){
$this->locationTable[$i] = new RegionLocationTableEntry(0, 0, 0);
}
}
public function getX() : int{
return $this->x;
}
public function getZ() : int{
return $this->z;
}
public function getFilePath() : string{
return $this->filePath;
}
}