minetest/src/database-leveldb.cpp

/*
Minetest
Copyright (C) 2013 celeron55, Perttu Ahola <celeron55@gmail.com>

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 2.1 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/

#include "config.h"

#if USE_LEVELDB
/*
LevelDB databases
*/


#include "database-leveldb.h"
#include "leveldb/db.h"

#include "map.h"
#include "mapsector.h"
#include "mapblock.h"
#include "serialization.h"
#include "main.h"
#include "settings.h"
#include "log.h"

Database_LevelDB::Database_LevelDB(ServerMap *map, std::string savedir)
{
	leveldb::Options options;
	options.create_if_missing = true;
	leveldb::Status status = leveldb::DB::Open(options, savedir + DIR_DELIM + "map.db", &m_database);
	assert(status.ok());
	srvmap = map;
}

int Database_LevelDB::Initialized(void)
{
	return 1;
}

void Database_LevelDB::beginSave() {}
void Database_LevelDB::endSave() {}

void Database_LevelDB::saveBlock(MapBlock *block)
{
	DSTACK(__FUNCTION_NAME);
	/*
		Dummy blocks are not written
	*/
	if(block->isDummy())
	{
		return;
	}

	// Format used for writing
	u8 version = SER_FMT_VER_HIGHEST_WRITE;
	// Get destination
	v3s16 p3d = block->getPos();

	/*
		[0] u8 serialization version
		[1] data
	*/

	std::ostringstream o(std::ios_base::binary);
	o.write((char*)&version, 1);
	// Write basic data
	block->serialize(o, version, true);
	// Write block to database
	std::string tmp = o.str();

	m_database->Put(leveldb::WriteOptions(), i64tos(getBlockAsInteger(p3d)), tmp);

	// We just wrote it to the disk so clear modified flag
	block->resetModified();
}

MapBlock* Database_LevelDB::loadBlock(v3s16 blockpos)
{
	v2s16 p2d(blockpos.X, blockpos.Z);

	std::string datastr;
	leveldb::Status s = m_database->Get(leveldb::ReadOptions(), i64tos(getBlockAsInteger(blockpos)), &datastr);

        if(s.ok()) {
                /*
                        Make sure sector is loaded
                */
                MapSector *sector = srvmap->createSector(p2d);

		try {
                	std::istringstream is(datastr, std::ios_base::binary);
                   	u8 version = SER_FMT_VER_INVALID;
                     	is.read((char*)&version, 1);

                     	if(is.fail())
                             	throw SerializationError("ServerMap::loadBlock(): Failed"
                                	             " to read MapBlock version");

                     	MapBlock *block = NULL;
                     	bool created_new = false;
                     	block = sector->getBlockNoCreateNoEx(blockpos.Y);
                     	if(block == NULL)
                     	{
                             	block = sector->createBlankBlockNoInsert(blockpos.Y);
                             	created_new = true;
                     	}
                     	// Read basic data
                     	block->deSerialize(is, version, true);
                     	// If it's a new block, insert it to the map
                     	if(created_new)
                             	sector->insertBlock(block);
                     	/*
                             	Save blocks loaded in old format in new format
                     	*/

                     	//if(version < SER_FMT_VER_HIGHEST || save_after_load)
                     	// Only save if asked to; no need to update version
                     	//if(save_after_load)
                        //     	saveBlock(block);
                     	// We just loaded it from, so it's up-to-date.
                     	block->resetModified();

             	}
             	catch(SerializationError &e)
             	{
                     	errorstream<<"Invalid block data in database"
                                     <<" ("<<blockpos.X<<","<<blockpos.Y<<","<<blockpos.Z<<")"
                                     <<" (SerializationError): "<<e.what()<<std::endl;
                     // TODO: Block should be marked as invalid in memory so that it is
                     // not touched but the game can run

                     	if(g_settings->getBool("ignore_world_load_errors")){
                             errorstream<<"Ignoring block load error. Duck and cover! "
                                             <<"(ignore_world_load_errors)"<<std::endl;
                     	} else {
                             throw SerializationError("Invalid block data in database");
                             //assert(0);
                     	}
             	}

                return srvmap->getBlockNoCreateNoEx(blockpos);  // should not be using this here
        }
	return(NULL);
}

void Database_LevelDB::listAllLoadableBlocks(std::list<v3s16> &dst)
{
	leveldb::Iterator* it = m_database->NewIterator(leveldb::ReadOptions());
	for (it->SeekToFirst(); it->Valid(); it->Next()) {
		dst.push_back(getIntegerAsBlock(stoi64(it->key().ToString())));
	}
	assert(it->status().ok());  // Check for any errors found during the scan
	delete it;
}

Database_LevelDB::~Database_LevelDB()
{
	delete m_database;
}
#endif