minetest/src/map.cpp

/*
Minetest
Copyright (C) 2010-2013 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 "map.h"
#include "mapsector.h"
#include "mapblock.h"
#include "filesys.h"
#include "voxel.h"
#include "voxelalgorithms.h"
#include "porting.h"
#include "serialization.h"
#include "nodemetadata.h"
#include "settings.h"
#include "log.h"
#include "profiler.h"
#include "nodedef.h"
#include "gamedef.h"
#include "util/directiontables.h"
#include "util/basic_macros.h"
#include "rollback_interface.h"
#include "environment.h"
#include "reflowscan.h"
#include "emerge.h"
#include "mapgen/mapgen_v6.h"
#include "mapgen/mg_biome.h"
#include "config.h"
#include "server.h"
#include "database/database.h"
#include "database/database-dummy.h"
#include "database/database-sqlite3.h"
#include "script/scripting_server.h"
#include <deque>
#include <queue>
#if USE_LEVELDB
#include "database/database-leveldb.h"
#endif
#if USE_REDIS
#include "database/database-redis.h"
#endif
#if USE_POSTGRESQL
#include "database/database-postgresql.h"
#endif


/*
	Map
*/

Map::Map(std::ostream &dout, IGameDef *gamedef):
	m_dout(dout),
	m_gamedef(gamedef),
	m_nodedef(gamedef->ndef())
{
}

Map::~Map()
{
	/*
		Free all MapSectors
	*/
	for (auto &sector : m_sectors) {
		delete sector.second;
	}
}

void Map::addEventReceiver(MapEventReceiver *event_receiver)
{
	m_event_receivers.insert(event_receiver);
}

void Map::removeEventReceiver(MapEventReceiver *event_receiver)
{
	m_event_receivers.erase(event_receiver);
}

void Map::dispatchEvent(MapEditEvent *event)
{
	for (MapEventReceiver *event_receiver : m_event_receivers) {
		event_receiver->onMapEditEvent(event);
	}
}

MapSector * Map::getSectorNoGenerateNoExNoLock(v2s16 p)
{
	if(m_sector_cache != NULL && p == m_sector_cache_p){
		MapSector * sector = m_sector_cache;
		return sector;
	}

	std::map<v2s16, MapSector*>::iterator n = m_sectors.find(p);

	if (n == m_sectors.end())
		return NULL;

	MapSector *sector = n->second;

	// Cache the last result
	m_sector_cache_p = p;
	m_sector_cache = sector;

	return sector;
}

MapSector * Map::getSectorNoGenerateNoEx(v2s16 p)
{
	return getSectorNoGenerateNoExNoLock(p);
}

MapSector * Map::getSectorNoGenerate(v2s16 p)
{
	MapSector *sector = getSectorNoGenerateNoEx(p);
	if(sector == NULL)
		throw InvalidPositionException();

	return sector;
}

MapBlock * Map::getBlockNoCreateNoEx(v3s16 p3d)
{
	v2s16 p2d(p3d.X, p3d.Z);
	MapSector * sector = getSectorNoGenerateNoEx(p2d);
	if(sector == NULL)
		return NULL;
	MapBlock *block = sector->getBlockNoCreateNoEx(p3d.Y);
	return block;
}

MapBlock * Map::getBlockNoCreate(v3s16 p3d)
{
	MapBlock *block = getBlockNoCreateNoEx(p3d);
	if(block == NULL)
		throw InvalidPositionException();
	return block;
}

bool Map::isNodeUnderground(v3s16 p)
{
	v3s16 blockpos = getNodeBlockPos(p);
	try{
		MapBlock * block = getBlockNoCreate(blockpos);
		return block->getIsUnderground();
	}
	catch(InvalidPositionException &e)
	{
		return false;
	}
}

bool Map::isValidPosition(v3s16 p)
{
	v3s16 blockpos = getNodeBlockPos(p);
	MapBlock *block = getBlockNoCreateNoEx(blockpos);
	return (block != NULL);
}

// Returns a CONTENT_IGNORE node if not found
MapNode Map::getNodeNoEx(v3s16 p, bool *is_valid_position)
{
	v3s16 blockpos = getNodeBlockPos(p);
	MapBlock *block = getBlockNoCreateNoEx(blockpos);
	if (block == NULL) {
		if (is_valid_position != NULL)
			*is_valid_position = false;
		return {CONTENT_IGNORE};
	}

	v3s16 relpos = p - blockpos*MAP_BLOCKSIZE;
	bool is_valid_p;
	MapNode node = block->getNodeNoCheck(relpos, &is_valid_p);
	if (is_valid_position != NULL)
		*is_valid_position = is_valid_p;
	return node;
}

#if 0
// Deprecated
// throws InvalidPositionException if not found
// TODO: Now this is deprecated, getNodeNoEx should be renamed
MapNode Map::getNode(v3s16 p)
{
	v3s16 blockpos = getNodeBlockPos(p);
	MapBlock *block = getBlockNoCreateNoEx(blockpos);
	if (block == NULL)
		throw InvalidPositionException();
	v3s16 relpos = p - blockpos*MAP_BLOCKSIZE;
	bool is_valid_position;
	MapNode node = block->getNodeNoCheck(relpos, &is_valid_position);
	if (!is_valid_position)
		throw InvalidPositionException();
	return node;
}
#endif

// throws InvalidPositionException if not found
void Map::setNode(v3s16 p, MapNode & n)
{
	v3s16 blockpos = getNodeBlockPos(p);
	MapBlock *block = getBlockNoCreate(blockpos);
	v3s16 relpos = p - blockpos*MAP_BLOCKSIZE;
	// Never allow placing CONTENT_IGNORE, it fucks up stuff
	if(n.getContent() == CONTENT_IGNORE){
		bool temp_bool;
		errorstream<<"Map::setNode(): Not allowing to place CONTENT_IGNORE"
				<<" while trying to replace \""
				<<m_nodedef->get(block->getNodeNoCheck(relpos, &temp_bool)).name
				<<"\" at "<<PP(p)<<" (block "<<PP(blockpos)<<")"<<std::endl;
		return;
	}
	block->setNodeNoCheck(relpos, n);
}

void Map::addNodeAndUpdate(v3s16 p, MapNode n,
		std::map<v3s16, MapBlock*> &modified_blocks,
		bool remove_metadata)
{
	// Collect old node for rollback
	RollbackNode rollback_oldnode(this, p, m_gamedef);

	// This is needed for updating the lighting
	MapNode oldnode = getNodeNoEx(p);

	// Remove node metadata
	if (remove_metadata) {
		removeNodeMetadata(p);
	}

	// Set the node on the map
	// Ignore light (because calling voxalgo::update_lighting_nodes)
	n.setLight(LIGHTBANK_DAY, 0, m_nodedef);
	n.setLight(LIGHTBANK_NIGHT, 0, m_nodedef);
	setNode(p, n);

	// Update lighting
	std::vector<std::pair<v3s16, MapNode> > oldnodes;
	oldnodes.emplace_back(p, oldnode);
	voxalgo::update_lighting_nodes(this, oldnodes, modified_blocks);

	for (auto &modified_block : modified_blocks) {
		modified_block.second->expireDayNightDiff();
	}

	// Report for rollback
	if(m_gamedef->rollback())
	{
		RollbackNode rollback_newnode(this, p, m_gamedef);
		RollbackAction action;
		action.setSetNode(p, rollback_oldnode, rollback_newnode);
		m_gamedef->rollback()->reportAction(action);
	}

	/*
		Add neighboring liquid nodes and this node to transform queue.
		(it's vital for the node itself to get updated last, if it was removed.)
	 */

	for (const v3s16 &dir : g_7dirs) {
		v3s16 p2 = p + dir;

		bool is_valid_position;
		MapNode n2 = getNodeNoEx(p2, &is_valid_position);
		if(is_valid_position &&
				(m_nodedef->get(n2).isLiquid() ||
				n2.getContent() == CONTENT_AIR))
			m_transforming_liquid.push_back(p2);
	}
}

void Map::removeNodeAndUpdate(v3s16 p,
		std::map<v3s16, MapBlock*> &modified_blocks)
{
	addNodeAndUpdate(p, MapNode(CONTENT_AIR), modified_blocks, true);
}

bool Map::addNodeWithEvent(v3s16 p, MapNode n, bool remove_metadata)
{
	MapEditEvent event;
	event.type = remove_metadata ? MEET_ADDNODE : MEET_SWAPNODE;
	event.p = p;
	event.n = n;

	bool succeeded = true;
	try{
		std::map<v3s16, MapBlock*> modified_blocks;
		addNodeAndUpdate(p, n, modified_blocks, remove_metadata);

		// Copy modified_blocks to event
		for (auto &modified_block : modified_blocks) {
			event.modified_blocks.insert(modified_block.first);
		}
	}
	catch(InvalidPositionException &e){
		succeeded = false;
	}

	dispatchEvent(&event);

	return succeeded;
}

bool Map::removeNodeWithEvent(v3s16 p)
{
	MapEditEvent event;
	event.type = MEET_REMOVENODE;
	event.p = p;

	bool succeeded = true;
	try{
		std::map<v3s16, MapBlock*> modified_blocks;
		removeNodeAndUpdate(p, modified_blocks);

		// Copy modified_blocks to event
		for (auto &modified_block : modified_blocks) {
			event.modified_blocks.insert(modified_block.first);
		}
	}
	catch(InvalidPositionException &e){
		succeeded = false;
	}

	dispatchEvent(&event);

	return succeeded;
}

struct TimeOrderedMapBlock {
	MapSector *sect;
	MapBlock *block;

	TimeOrderedMapBlock(MapSector *sect, MapBlock *block) :
		sect(sect),
		block(block)
	{}

	bool operator<(const TimeOrderedMapBlock &b) const
	{
		return block->getUsageTimer() < b.block->getUsageTimer();
	};
};

/*
	Updates usage timers
*/
void Map::timerUpdate(float dtime, float unload_timeout, u32 max_loaded_blocks,
		std::vector<v3s16> *unloaded_blocks)
{
	bool save_before_unloading = (mapType() == MAPTYPE_SERVER);

	// Profile modified reasons
	Profiler modprofiler;

	std::vector<v2s16> sector_deletion_queue;
	u32 deleted_blocks_count = 0;
	u32 saved_blocks_count = 0;
	u32 block_count_all = 0;

	beginSave();

	// If there is no practical limit, we spare creation of mapblock_queue
	if (max_loaded_blocks == U32_MAX) {
		for (auto &sector_it : m_sectors) {
			MapSector *sector = sector_it.second;

			bool all_blocks_deleted = true;

			MapBlockVect blocks;
			sector->getBlocks(blocks);

			for (MapBlock *block : blocks) {
				block->incrementUsageTimer(dtime);

				if (block->refGet() == 0
						&& block->getUsageTimer() > unload_timeout) {
					v3s16 p = block->getPos();

					// Save if modified
					if (block->getModified() != MOD_STATE_CLEAN
							&& save_before_unloading) {
						modprofiler.add(block->getModifiedReasonString(), 1);
						if (!saveBlock(block))
							continue;
						saved_blocks_count++;
					}

					// Delete from memory
					sector->deleteBlock(block);

					if (unloaded_blocks)
						unloaded_blocks->push_back(p);

					deleted_blocks_count++;
				} else {
					all_blocks_deleted = false;
					block_count_all++;
				}
			}

			if (all_blocks_deleted) {
				sector_deletion_queue.push_back(sector_it.first);
			}
		}
	} else {
		std::priority_queue<TimeOrderedMapBlock> mapblock_queue;
		for (auto &sector_it : m_sectors) {
			MapSector *sector = sector_it.second;

			MapBlockVect blocks;
			sector->getBlocks(blocks);

			for (MapBlock *block : blocks) {
				block->incrementUsageTimer(dtime);
				mapblock_queue.push(TimeOrderedMapBlock(sector, block));
			}
		}
		block_count_all = mapblock_queue.size();
		// Delete old blocks, and blocks over the limit from the memory
		while (!mapblock_queue.empty() && (mapblock_queue.size() > max_loaded_blocks
				|| mapblock_queue.top().block->getUsageTimer() > unload_timeout)) {
			TimeOrderedMapBlock b = mapblock_queue.top();
			mapblock_queue.pop();

			MapBlock *block = b.block;

			if (block->refGet() != 0)
				continue;

			v3s16 p = block->getPos();

			// Save if modified
			if (block->getModified() != MOD_STATE_CLEAN && save_before_unloading) {
				modprofiler.add(block->getModifiedReasonString(), 1);
				if (!saveBlock(block))
					continue;
				saved_blocks_count++;
			}

			// Delete from memory
			b.sect->deleteBlock(block);

			if (unloaded_blocks)
				unloaded_blocks->push_back(p);

			deleted_blocks_count++;
			block_count_all--;
		}
		// Delete empty sectors
		for (auto &sector_it : m_sectors) {
			if (sector_it.second->empty()) {
				sector_deletion_queue.push_back(sector_it.first);
			}
		}
	}
	endSave();

	// Finally delete the empty sectors
	deleteSectors(sector_deletion_queue);

	if(deleted_blocks_count != 0)
	{
		PrintInfo(infostream); // ServerMap/ClientMap:
		infostream<<"Unloaded "<<deleted_blocks_count
				<<" blocks from memory";
		if(save_before_unloading)
			infostream<<", of which "<<saved_blocks_count<<" were written";
		infostream<<", "<<block_count_all<<" blocks in memory";
		infostream<<"."<<std::endl;
		if(saved_blocks_count != 0){
			PrintInfo(infostream); // ServerMap/ClientMap:
			infostream<<"Blocks modified by: "<<std::endl;
			modprofiler.print(infostream);
		}
	}
}

void Map::unloadUnreferencedBlocks(std::vector<v3s16> *unloaded_blocks)
{
	timerUpdate(0.0, -1.0, 0, unloaded_blocks);
}

void Map::deleteSectors(std::vector<v2s16> &sectorList)
{
	for (v2s16 j : sectorList) {
		MapSector *sector = m_sectors[j];
		// If sector is in sector cache, remove it from there
		if(m_sector_cache == sector)
			m_sector_cache = NULL;
		// Remove from map and delete
		m_sectors.erase(j);
		delete sector;
	}
}

void Map::PrintInfo(std::ostream &out)
{
	out<<"Map: ";
}

#define WATER_DROP_BOOST 4

enum NeighborType : u8 {
	NEIGHBOR_UPPER,
	NEIGHBOR_SAME_LEVEL,
	NEIGHBOR_LOWER
};

struct NodeNeighbor {
	MapNode n;
	NeighborType t;
	v3s16 p;

	NodeNeighbor()
		: n(CONTENT_AIR), t(NEIGHBOR_SAME_LEVEL)
	{ }

	NodeNeighbor(const MapNode &node, NeighborType n_type, const v3s16 &pos)
		: n(node),
		  t(n_type),
		  p(pos)
	{ }
};

void Map::transforming_liquid_add(v3s16 p) {
        m_transforming_liquid.push_back(p);
}

void Map::transformLiquids(std::map<v3s16, MapBlock*> &modified_blocks,
		ServerEnvironment *env)
{
	u32 loopcount = 0;
	u32 initial_size = m_transforming_liquid.size();

	/*if(initial_size != 0)
		infostream<<"transformLiquids(): initial_size="<<initial_size<<std::endl;*/

	// list of nodes that due to viscosity have not reached their max level height
	std::deque<v3s16> must_reflow;

	std::vector<std::pair<v3s16, MapNode> > changed_nodes;

	u32 liquid_loop_max = g_settings->getS32("liquid_loop_max");
	u32 loop_max = liquid_loop_max;

#if 0

	/* If liquid_loop_max is not keeping up with the queue size increase
	 * loop_max up to a maximum of liquid_loop_max * dedicated_server_step.
	 */
	if (m_transforming_liquid.size() > loop_max * 2) {
		// "Burst" mode
		float server_step = g_settings->getFloat("dedicated_server_step");
		if (m_transforming_liquid_loop_count_multiplier - 1.0 < server_step)
			m_transforming_liquid_loop_count_multiplier *= 1.0 + server_step / 10;
	} else {
		m_transforming_liquid_loop_count_multiplier = 1.0;
	}

	loop_max *= m_transforming_liquid_loop_count_multiplier;
#endif

	while (m_transforming_liquid.size() != 0)
	{
		// This should be done here so that it is done when continue is used
		if (loopcount >= initial_size || loopcount >= loop_max)
			break;
		loopcount++;

		/*
			Get a queued transforming liquid node
		*/
		v3s16 p0 = m_transforming_liquid.front();
		m_transforming_liquid.pop_front();

		MapNode n0 = getNodeNoEx(p0);

		/*
			Collect information about current node
		 */
		s8 liquid_level = -1;
		// The liquid node which will be placed there if
		// the liquid flows into this node.
		content_t liquid_kind = CONTENT_IGNORE;
		// The node which will be placed there if liquid
		// can't flow into this node.
		content_t floodable_node = CONTENT_AIR;
		const ContentFeatures &cf = m_nodedef->get(n0);
		LiquidType liquid_type = cf.liquid_type;
		switch (liquid_type) {
			case LIQUID_SOURCE:
				liquid_level = LIQUID_LEVEL_SOURCE;
				liquid_kind = m_nodedef->getId(cf.liquid_alternative_flowing);
				break;
			case LIQUID_FLOWING:
				liquid_level = (n0.param2 & LIQUID_LEVEL_MASK);
				liquid_kind = n0.getContent();
				break;
			case LIQUID_NONE:
				// if this node is 'floodable', it *could* be transformed
				// into a liquid, otherwise, continue with the next node.
				if (!cf.floodable)
					continue;
				floodable_node = n0.getContent();
				liquid_kind = CONTENT_AIR;
				break;
		}

		/*
			Collect information about the environment
		 */
		const v3s16 *dirs = g_6dirs;
		NodeNeighbor sources[6]; // surrounding sources
		int num_sources = 0;
		NodeNeighbor flows[6]; // surrounding flowing liquid nodes
		int num_flows = 0;
		NodeNeighbor airs[6]; // surrounding air
		int num_airs = 0;
		NodeNeighbor neutrals[6]; // nodes that are solid or another kind of liquid
		int num_neutrals = 0;
		bool flowing_down = false;
		bool ignored_sources = false;
		for (u16 i = 0; i < 6; i++) {
			NeighborType nt = NEIGHBOR_SAME_LEVEL;
			switch (i) {
				case 1:
					nt = NEIGHBOR_UPPER;
					break;
				case 4:
					nt = NEIGHBOR_LOWER;
					break;
				default:
					break;
			}
			v3s16 npos = p0 + dirs[i];
			NodeNeighbor nb(getNodeNoEx(npos), nt, npos);
			const ContentFeatures &cfnb = m_nodedef->get(nb.n);
			switch (m_nodedef->get(nb.n.getContent()).liquid_type) {
				case LIQUID_NONE:
					if (cfnb.floodable) {
						airs[num_airs++] = nb;
						// if the current node is a water source the neighbor
						// should be enqueded for transformation regardless of whether the
						// current node changes or not.
						if (nb.t != NEIGHBOR_UPPER && liquid_type != LIQUID_NONE)
							m_transforming_liquid.push_back(npos);
						// if the current node happens to be a flowing node, it will start to flow down here.
						if (nb.t == NEIGHBOR_LOWER)
							flowing_down = true;
					} else {
						neutrals[num_neutrals++] = nb;
						if (nb.n.getContent() == CONTENT_IGNORE) {
							// If node below is ignore prevent water from
							// spreading outwards and otherwise prevent from
							// flowing away as ignore node might be the source
							if (nb.t == NEIGHBOR_LOWER)
								flowing_down = true;
							else
								ignored_sources = true;
						}
					}
					break;
				case LIQUID_SOURCE:
					// if this node is not (yet) of a liquid type, choose the first liquid type we encounter
					if (liquid_kind == CONTENT_AIR)
						liquid_kind = m_nodedef->getId(cfnb.liquid_alternative_flowing);
					if (m_nodedef->getId(cfnb.liquid_alternative_flowing) != liquid_kind) {
						neutrals[num_neutrals++] = nb;
					} else {
						// Do not count bottom source, it will screw things up
						if(dirs[i].Y != -1)
							sources[num_sources++] = nb;
					}
					break;
				case LIQUID_FLOWING:
					// if this node is not (yet) of a liquid type, choose the first liquid type we encounter
					if (liquid_kind == CONTENT_AIR)
						liquid_kind = m_nodedef->getId(cfnb.liquid_alternative_flowing);
					if (m_nodedef->getId(cfnb.liquid_alternative_flowing) != liquid_kind) {
						neutrals[num_neutrals++] = nb;
					} else {
						flows[num_flows++] = nb;
						if (nb.t == NEIGHBOR_LOWER)
							flowing_down = true;
					}
					break;
			}
		}

		/*
			decide on the type (and possibly level) of the current node
		 */
		content_t new_node_content;
		s8 new_node_level = -1;
		s8 max_node_level = -1;

		u8 range = m_nodedef->get(liquid_kind).liquid_range;
		if (range > LIQUID_LEVEL_MAX + 1)
			range = LIQUID_LEVEL_MAX + 1;

		if ((num_sources >= 2 && m_nodedef->get(liquid_kind).liquid_renewable) || liquid_type == LIQUID_SOURCE) {
			// liquid_kind will be set to either the flowing alternative of the node (if it's a liquid)
			// or the flowing alternative of the first of the surrounding sources (if it's air), so
			// it's perfectly safe to use liquid_kind here to determine the new node content.
			new_node_content = m_nodedef->getId(m_nodedef->get(liquid_kind).liquid_alternative_source);
		} else if (num_sources >= 1 && sources[0].t != NEIGHBOR_LOWER) {
			// liquid_kind is set properly, see above
			max_node_level = new_node_level = LIQUID_LEVEL_MAX;
			if (new_node_level >= (LIQUID_LEVEL_MAX + 1 - range))
				new_node_content = liquid_kind;
			else
				new_node_content = floodable_node;
		} else if (ignored_sources && liquid_level >= 0) {
			// Maybe there are neighbouring sources that aren't loaded yet
			// so prevent flowing away.
			new_node_level = liquid_level;
			new_node_content = liquid_kind;
		} else {
			// no surrounding sources, so get the maximum level that can flow into this node
			for (u16 i = 0; i < num_flows; i++) {
				u8 nb_liquid_level = (flows[i].n.param2 & LIQUID_LEVEL_MASK);
				switch (flows[i].t) {
					case NEIGHBOR_UPPER:
						if (nb_liquid_level + WATER_DROP_BOOST > max_node_level) {
							max_node_level = LIQUID_LEVEL_MAX;
							if (nb_liquid_level + WATER_DROP_BOOST < LIQUID_LEVEL_MAX)
								max_node_level = nb_liquid_level + WATER_DROP_BOOST;
						} else if (nb_liquid_level > max_node_level) {
							max_node_level = nb_liquid_level;
						}
						break;
					case NEIGHBOR_LOWER:
						break;
					case NEIGHBOR_SAME_LEVEL:
						if ((flows[i].n.param2 & LIQUID_FLOW_DOWN_MASK) != LIQUID_FLOW_DOWN_MASK &&
								nb_liquid_level > 0 && nb_liquid_level - 1 > max_node_level)
							max_node_level = nb_liquid_level - 1;
						break;
				}
			}

			u8 viscosity = m_nodedef->get(liquid_kind).liquid_viscosity;
			if (viscosity > 1 && max_node_level != liquid_level) {
				// amount to gain, limited by viscosity
				// must be at least 1 in absolute value
				s8 level_inc = max_node_level - liquid_level;
				if (level_inc < -viscosity || level_inc > viscosity)
					new_node_level = liquid_level + level_inc/viscosity;
				else if (level_inc < 0)
					new_node_level = liquid_level - 1;
				else if (level_inc > 0)
					new_node_level = liquid_level + 1;
				if (new_node_level != max_node_level)
					must_reflow.push_back(p0);
			} else {
				new_node_level = max_node_level;
			}

			if (max_node_level >= (LIQUID_LEVEL_MAX + 1 - range))
				new_node_content = liquid_kind;
			else
				new_node_content = floodable_node;

		}

		/*
			check if anything has changed. if not, just continue with the next node.
		 */
		if (new_node_content == n0.getContent() &&
				(m_nodedef->get(n0.getContent()).liquid_type != LIQUID_FLOWING ||
				((n0.param2 & LIQUID_LEVEL_MASK) == (u8)new_node_level &&
				((n0.param2 & LIQUID_FLOW_DOWN_MASK) == LIQUID_FLOW_DOWN_MASK)
				== flowing_down)))
			continue;


		/*
			update the current node
		 */
		MapNode n00 = n0;
		//bool flow_down_enabled = (flowing_down && ((n0.param2 & LIQUID_FLOW_DOWN_MASK) != LIQUID_FLOW_DOWN_MASK));
		if (m_nodedef->get(new_node_content).liquid_type == LIQUID_FLOWING) {
			// set level to last 3 bits, flowing down bit to 4th bit
			n0.param2 = (flowing_down ? LIQUID_FLOW_DOWN_MASK : 0x00) | (new_node_level & LIQUID_LEVEL_MASK);
		} else {
			// set the liquid level and flow bit to 0
			n0.param2 = ~(LIQUID_LEVEL_MASK | LIQUID_FLOW_DOWN_MASK);
		}

		// change the node.
		n0.setContent(new_node_content);

		// on_flood() the node
		if (floodable_node != CONTENT_AIR) {
			if (env->getScriptIface()->node_on_flood(p0, n00, n0))
				continue;
		}

		// Ignore light (because calling voxalgo::update_lighting_nodes)
		n0.setLight(LIGHTBANK_DAY, 0, m_nodedef);
		n0.setLight(LIGHTBANK_NIGHT, 0, m_nodedef);

		// Find out whether there is a suspect for this action
		std::string suspect;
		if (m_gamedef->rollback())
			suspect = m_gamedef->rollback()->getSuspect(p0, 83, 1);

		if (m_gamedef->rollback() && !suspect.empty()) {
			// Blame suspect
			RollbackScopeActor rollback_scope(m_gamedef->rollback(), suspect, true);
			// Get old node for rollback
			RollbackNode rollback_oldnode(this, p0, m_gamedef);
			// Set node
			setNode(p0, n0);
			// Report
			RollbackNode rollback_newnode(this, p0, m_gamedef);
			RollbackAction action;
			action.setSetNode(p0, rollback_oldnode, rollback_newnode);
			m_gamedef->rollback()->reportAction(action);
		} else {
			// Set node
			setNode(p0, n0);
		}

		v3s16 blockpos = getNodeBlockPos(p0);
		MapBlock *block = getBlockNoCreateNoEx(blockpos);
		if (block != NULL) {
			modified_blocks[blockpos] =  block;
			changed_nodes.emplace_back(p0, n00);
		}

		/*
			enqueue neighbors for update if neccessary
		 */
		switch (m_nodedef->get(n0.getContent()).liquid_type) {
			case LIQUID_SOURCE:
			case LIQUID_FLOWING:
				// make sure source flows into all neighboring nodes
				for (u16 i = 0; i < num_flows; i++)
					if (flows[i].t != NEIGHBOR_UPPER)
						m_transforming_liquid.push_back(flows[i].p);
				for (u16 i = 0; i < num_airs; i++)
					if (airs[i].t != NEIGHBOR_UPPER)
						m_transforming_liquid.push_back(airs[i].p);
				break;
			case LIQUID_NONE:
				// this flow has turned to air; neighboring flows might need to do the same
				for (u16 i = 0; i < num_flows; i++)
					m_transforming_liquid.push_back(flows[i].p);
				break;
		}
	}
	//infostream<<"Map::transformLiquids(): loopcount="<<loopcount<<std::endl;

	for (auto &iter : must_reflow)
		m_transforming_liquid.push_back(iter);

	voxalgo::update_lighting_nodes(this, changed_nodes, modified_blocks);


	/* ----------------------------------------------------------------------
	 * Manage the queue so that it does not grow indefinately
	 */
	u16 time_until_purge = g_settings->getU16("liquid_queue_purge_time");

	if (time_until_purge == 0)
		return; // Feature disabled

	time_until_purge *= 1000;	// seconds -> milliseconds

	u64 curr_time = porting::getTimeMs();
	u32 prev_unprocessed = m_unprocessed_count;
	m_unprocessed_count = m_transforming_liquid.size();

	// if unprocessed block count is decreasing or stable
	if (m_unprocessed_count <= prev_unprocessed) {
		m_queue_size_timer_started = false;
	} else {
		if (!m_queue_size_timer_started)
			m_inc_trending_up_start_time = curr_time;
		m_queue_size_timer_started = true;
	}

	// Account for curr_time overflowing
	if (m_queue_size_timer_started && m_inc_trending_up_start_time > curr_time)
		m_queue_size_timer_started = false;

	/* If the queue has been growing for more than liquid_queue_purge_time seconds
	 * and the number of unprocessed blocks is still > liquid_loop_max then we
	 * cannot keep up; dump the oldest blocks from the queue so that the queue
	 * has liquid_loop_max items in it
	 */
	if (m_queue_size_timer_started
			&& curr_time - m_inc_trending_up_start_time > time_until_purge
			&& m_unprocessed_count > liquid_loop_max) {

		size_t dump_qty = m_unprocessed_count - liquid_loop_max;

		infostream << "transformLiquids(): DUMPING " << dump_qty
		           << " blocks from the queue" << std::endl;

		while (dump_qty--)
			m_transforming_liquid.pop_front();

		m_queue_size_timer_started = false; // optimistically assume we can keep up now
		m_unprocessed_count = m_transforming_liquid.size();
	}
}

std::vector<v3s16> Map::findNodesWithMetadata(v3s16 p1, v3s16 p2)
{
	std::vector<v3s16> positions_with_meta;

	sortBoxVerticies(p1, p2);
	v3s16 bpmin = getNodeBlockPos(p1);
	v3s16 bpmax = getNodeBlockPos(p2);

	VoxelArea area(p1, p2);

	for (s16 z = bpmin.Z; z <= bpmax.Z; z++)
	for (s16 y = bpmin.Y; y <= bpmax.Y; y++)
	for (s16 x = bpmin.X; x <= bpmax.X; x++) {
		v3s16 blockpos(x, y, z);

		MapBlock *block = getBlockNoCreateNoEx(blockpos);
		if (!block) {
			verbosestream << "Map::getNodeMetadata(): Need to emerge "
				<< PP(blockpos) << std::endl;
			block = emergeBlock(blockpos, false);
		}
		if (!block) {
			infostream << "WARNING: Map::getNodeMetadata(): Block not found"
				<< std::endl;
			continue;
		}

		v3s16 p_base = blockpos * MAP_BLOCKSIZE;
		std::vector<v3s16> keys = block->m_node_metadata.getAllKeys();
		for (size_t i = 0; i != keys.size(); i++) {
			v3s16 p(keys[i] + p_base);
			if (!area.contains(p))
				continue;

			positions_with_meta.push_back(p);
		}
	}

	return positions_with_meta;
}

NodeMetadata *Map::getNodeMetadata(v3s16 p)
{
	v3s16 blockpos = getNodeBlockPos(p);
	v3s16 p_rel = p - blockpos*MAP_BLOCKSIZE;
	MapBlock *block = getBlockNoCreateNoEx(blockpos);
	if(!block){
		infostream<<"Map::getNodeMetadata(): Need to emerge "
				<<PP(blockpos)<<std::endl;
		block = emergeBlock(blockpos, false);
	}
	if(!block){
		warningstream<<"Map::getNodeMetadata(): Block not found"
				<<std::endl;
		return NULL;
	}
	NodeMetadata *meta = block->m_node_metadata.get(p_rel);
	return meta;
}

bool Map::setNodeMetadata(v3s16 p, NodeMetadata *meta)
{
	v3s16 blockpos = getNodeBlockPos(p);
	v3s16 p_rel = p - blockpos*MAP_BLOCKSIZE;
	MapBlock *block = getBlockNoCreateNoEx(blockpos);
	if(!block){
		infostream<<"Map::setNodeMetadata(): Need to emerge "
				<<PP(blockpos)<<std::endl;
		block = emergeBlock(blockpos, false);
	}
	if(!block){
		warningstream<<"Map::setNodeMetadata(): Block not found"
				<<std::endl;
		return false;
	}
	block->m_node_metadata.set(p_rel, meta);
	return true;
}

void Map::removeNodeMetadata(v3s16 p)
{
	v3s16 blockpos = getNodeBlockPos(p);
	v3s16 p_rel = p - blockpos*MAP_BLOCKSIZE;
	MapBlock *block = getBlockNoCreateNoEx(blockpos);
	if(block == NULL)
	{
		warningstream<<"Map::removeNodeMetadata(): Block not found"
				<<std::endl;
		return;
	}
	block->m_node_metadata.remove(p_rel);
}

NodeTimer Map::getNodeTimer(v3s16 p)
{
	v3s16 blockpos = getNodeBlockPos(p);
	v3s16 p_rel = p - blockpos*MAP_BLOCKSIZE;
	MapBlock *block = getBlockNoCreateNoEx(blockpos);
	if(!block){
		infostream<<"Map::getNodeTimer(): Need to emerge "
				<<PP(blockpos)<<std::endl;
		block = emergeBlock(blockpos, false);
	}
	if(!block){
		warningstream<<"Map::getNodeTimer(): Block not found"
				<<std::endl;
		return NodeTimer();
	}
	NodeTimer t = block->m_node_timers.get(p_rel);
	NodeTimer nt(t.timeout, t.elapsed, p);
	return nt;
}

void Map::setNodeTimer(const NodeTimer &t)
{
	v3s16 p = t.position;
	v3s16 blockpos = getNodeBlockPos(p);
	v3s16 p_rel = p - blockpos*MAP_BLOCKSIZE;
	MapBlock *block = getBlockNoCreateNoEx(blockpos);
	if(!block){
		infostream<<"Map::setNodeTimer(): Need to emerge "
				<<PP(blockpos)<<std::endl;
		block = emergeBlock(blockpos, false);
	}
	if(!block){
		warningstream<<"Map::setNodeTimer(): Block not found"
				<<std::endl;
		return;
	}
	NodeTimer nt(t.timeout, t.elapsed, p_rel);
	block->m_node_timers.set(nt);
}

void Map::removeNodeTimer(v3s16 p)
{
	v3s16 blockpos = getNodeBlockPos(p);
	v3s16 p_rel = p - blockpos*MAP_BLOCKSIZE;
	MapBlock *block = getBlockNoCreateNoEx(blockpos);
	if(block == NULL)
	{
		warningstream<<"Map::removeNodeTimer(): Block not found"
				<<std::endl;
		return;
	}
	block->m_node_timers.remove(p_rel);
}

bool Map::isOccluded(v3s16 p0, v3s16 p1, float step, float stepfac,
		float start_off, float end_off, u32 needed_count)
{
	float d0 = (float)BS * p0.getDistanceFrom(p1);
	v3s16 u0 = p1 - p0;
	v3f uf = v3f(u0.X, u0.Y, u0.Z) * BS;
	uf.normalize();
	v3f p0f = v3f(p0.X, p0.Y, p0.Z) * BS;
	u32 count = 0;
	for(float s=start_off; s<d0+end_off; s+=step){
		v3f pf = p0f + uf * s;
		v3s16 p = floatToInt(pf, BS);
		MapNode n = getNodeNoEx(p);
		const ContentFeatures &f = m_nodedef->get(n);
		if(f.drawtype == NDT_NORMAL){
			// not transparent, see ContentFeature::updateTextures
			count++;
			if(count >= needed_count)
				return true;
		}
		step *= stepfac;
	}
	return false;
}

bool Map::isBlockOccluded(MapBlock *block, v3s16 cam_pos_nodes) {
	v3s16 cpn = block->getPos() * MAP_BLOCKSIZE;
	cpn += v3s16(MAP_BLOCKSIZE / 2, MAP_BLOCKSIZE / 2, MAP_BLOCKSIZE / 2);
	float step = BS * 1;
	float stepfac = 1.1;
	float startoff = BS * 1;
	// The occlusion search of 'isOccluded()' must stop short of the target
	// point by distance 'endoff' (end offset) to not enter the target mapblock.
	// For the 8 mapblock corners 'endoff' must therefore be the maximum diagonal
	// of a mapblock, because we must consider all view angles.
	// sqrt(1^2 + 1^2 + 1^2) = 1.732
	float endoff = -BS * MAP_BLOCKSIZE * 1.732050807569;
	s16 bs2 = MAP_BLOCKSIZE / 2 + 1;
	// to reduce the likelihood of falsely occluded blocks
	// require at least two solid blocks
	// this is a HACK, we should think of a more precise algorithm
	u32 needed_count = 2;

	return (
		// For the central point of the mapblock 'endoff' can be halved
		isOccluded(cam_pos_nodes, cpn,
			step, stepfac, startoff, endoff / 2.0f, needed_count) &&
		isOccluded(cam_pos_nodes, cpn + v3s16(bs2,bs2,bs2),
			step, stepfac, startoff, endoff, needed_count) &&
		isOccluded(cam_pos_nodes, cpn + v3s16(bs2,bs2,-bs2),
			step, stepfac, startoff, endoff, needed_count) &&
		isOccluded(cam_pos_nodes, cpn + v3s16(bs2,-bs2,bs2),
			step, stepfac, startoff, endoff, needed_count) &&
		isOccluded(cam_pos_nodes, cpn + v3s16(bs2,-bs2,-bs2),
			step, stepfac, startoff, endoff, needed_count) &&
		isOccluded(cam_pos_nodes, cpn + v3s16(-bs2,bs2,bs2),
			step, stepfac, startoff, endoff, needed_count) &&
		isOccluded(cam_pos_nodes, cpn + v3s16(-bs2,bs2,-bs2),
			step, stepfac, startoff, endoff, needed_count) &&
		isOccluded(cam_pos_nodes, cpn + v3s16(-bs2,-bs2,bs2),
			step, stepfac, startoff, endoff, needed_count) &&
		isOccluded(cam_pos_nodes, cpn + v3s16(-bs2,-bs2,-bs2),
			step, stepfac, startoff, endoff, needed_count));
}

/*
	ServerMap
*/
ServerMap::ServerMap(const std::string &savedir, IGameDef *gamedef,
		EmergeManager *emerge):
	Map(dout_server, gamedef),
	settings_mgr(g_settings, savedir + DIR_DELIM + "map_meta.txt"),
	m_emerge(emerge)
{
	verbosestream<<FUNCTION_NAME<<std::endl;

	// Tell the EmergeManager about our MapSettingsManager
	emerge->map_settings_mgr = &settings_mgr;

	/*
		Try to load map; if not found, create a new one.
	*/

	// Determine which database backend to use
	std::string conf_path = savedir + DIR_DELIM + "world.mt";
	Settings conf;
	bool succeeded = conf.readConfigFile(conf_path.c_str());
	if (!succeeded || !conf.exists("backend")) {
		// fall back to sqlite3
		conf.set("backend", "sqlite3");
	}
	std::string backend = conf.get("backend");
	dbase = createDatabase(backend, savedir, conf);
	if (conf.exists("readonly_backend")) {
		std::string readonly_dir = savedir + DIR_DELIM + "readonly";
		dbase_ro = createDatabase(conf.get("readonly_backend"), readonly_dir, conf);
	}
	if (!conf.updateConfigFile(conf_path.c_str()))
		errorstream << "ServerMap::ServerMap(): Failed to update world.mt!" << std::endl;

	m_savedir = savedir;
	m_map_saving_enabled = false;

	try {
		// If directory exists, check contents and load if possible
		if (fs::PathExists(m_savedir)) {
			// If directory is empty, it is safe to save into it.
			if (fs::GetDirListing(m_savedir).empty()) {
				infostream<<"ServerMap: Empty save directory is valid."
						<<std::endl;
				m_map_saving_enabled = true;
			}
			else
			{

				if (settings_mgr.loadMapMeta()) {
					infostream << "ServerMap: Metadata loaded from "
						<< savedir << std::endl;
				} else {
					infostream << "ServerMap: Metadata could not be loaded "
						"from " << savedir << ", assuming valid save "
						"directory." << std::endl;
				}

				m_map_saving_enabled = true;
				// Map loaded, not creating new one
				return;
			}
		}
		// If directory doesn't exist, it is safe to save to it
		else{
			m_map_saving_enabled = true;
		}
	}
	catch(std::exception &e)
	{
		warningstream<<"ServerMap: Failed to load map from "<<savedir
				<<", exception: "<<e.what()<<std::endl;
		infostream<<"Please remove the map or fix it."<<std::endl;
		warningstream<<"Map saving will be disabled."<<std::endl;
	}
}

ServerMap::~ServerMap()
{
	verbosestream<<FUNCTION_NAME<<std::endl;

	try
	{
		if (m_map_saving_enabled) {
			// Save only changed parts
			save(MOD_STATE_WRITE_AT_UNLOAD);
			infostream << "ServerMap: Saved map to " << m_savedir << std::endl;
		} else {
			infostream << "ServerMap: Map not saved" << std::endl;
		}
	}
	catch(std::exception &e)
	{
		infostream<<"ServerMap: Failed to save map to "<<m_savedir
				<<", exception: "<<e.what()<<std::endl;
	}

	/*
		Close database if it was opened
	*/
	delete dbase;
	if (dbase_ro)
		delete dbase_ro;

#if 0
	/*
		Free all MapChunks
	*/
	core::map<v2s16, MapChunk*>::Iterator i = m_chunks.getIterator();
	for(; i.atEnd() == false; i++)
	{
		MapChunk *chunk = i.getNode()->getValue();
		delete chunk;
	}
#endif
}

MapgenParams *ServerMap::getMapgenParams()
{
	// getMapgenParams() should only ever be called after Server is initialized
	assert(settings_mgr.mapgen_params != NULL);
	return settings_mgr.mapgen_params;
}

u64 ServerMap::getSeed()
{
	return getMapgenParams()->seed;
}

s16 ServerMap::getWaterLevel()
{
	return getMapgenParams()->water_level;
}

bool ServerMap::blockpos_over_mapgen_limit(v3s16 p)
{
	const s16 mapgen_limit_bp = rangelim(
		getMapgenParams()->mapgen_limit, 0, MAX_MAP_GENERATION_LIMIT) /
		MAP_BLOCKSIZE;
	return p.X < -mapgen_limit_bp ||
		p.X >  mapgen_limit_bp ||
		p.Y < -mapgen_limit_bp ||
		p.Y >  mapgen_limit_bp ||
		p.Z < -mapgen_limit_bp ||
		p.Z >  mapgen_limit_bp;
}

bool ServerMap::initBlockMake(v3s16 blockpos, BlockMakeData *data)
{
	s16 csize = getMapgenParams()->chunksize;
	v3s16 bpmin = EmergeManager::getContainingChunk(blockpos, csize);
	v3s16 bpmax = bpmin + v3s16(1, 1, 1) * (csize - 1);

	bool enable_mapgen_debug_info = m_emerge->enable_mapgen_debug_info;
	EMERGE_DBG_OUT("initBlockMake(): " PP(bpmin) " - " PP(bpmax));

	v3s16 extra_borders(1, 1, 1);
	v3s16 full_bpmin = bpmin - extra_borders;
	v3s16 full_bpmax = bpmax + extra_borders;

	// Do nothing if not inside mapgen limits (+-1 because of neighbors)
	if (blockpos_over_mapgen_limit(full_bpmin) ||
			blockpos_over_mapgen_limit(full_bpmax))
		return false;

	data->seed = getSeed();
	data->blockpos_min = bpmin;
	data->blockpos_max = bpmax;
	data->blockpos_requested = blockpos;
	data->nodedef = m_nodedef;

	/*
		Create the whole area of this and the neighboring blocks
	*/
	for (s16 x = full_bpmin.X; x <= full_bpmax.X; x++)
	for (s16 z = full_bpmin.Z; z <= full_bpmax.Z; z++) {
		v2s16 sectorpos(x, z);
		// Sector metadata is loaded from disk if not already loaded.
		MapSector *sector = createSector(sectorpos);
		FATAL_ERROR_IF(sector == NULL, "createSector() failed");

		for (s16 y = full_bpmin.Y; y <= full_bpmax.Y; y++) {
			v3s16 p(x, y, z);

			MapBlock *block = emergeBlock(p, false);
			if (block == NULL) {
				block = createBlock(p);

				// Block gets sunlight if this is true.
				// Refer to the map generator heuristics.
				bool ug = m_emerge->isBlockUnderground(p);
				block->setIsUnderground(ug);
			}
		}
	}

	/*
		Now we have a big empty area.

		Make a ManualMapVoxelManipulator that contains this and the
		neighboring blocks
	*/

	data->vmanip = new MMVManip(this);
	data->vmanip->initialEmerge(full_bpmin, full_bpmax);

	// Note: we may need this again at some point.
#if 0
	// Ensure none of the blocks to be generated were marked as
	// containing CONTENT_IGNORE
	for (s16 z = blockpos_min.Z; z <= blockpos_max.Z; z++) {
		for (s16 y = blockpos_min.Y; y <= blockpos_max.Y; y++) {
			for (s16 x = blockpos_min.X; x <= blockpos_max.X; x++) {
				core::map<v3s16, u8>::Node *n;
				n = data->vmanip->m_loaded_blocks.find(v3s16(x, y, z));
				if (n == NULL)
					continue;
				u8 flags = n->getValue();
				flags &= ~VMANIP_BLOCK_CONTAINS_CIGNORE;
				n->setValue(flags);
			}
		}
	}
#endif

	// Data is ready now.
	return true;
}

void ServerMap::finishBlockMake(BlockMakeData *data,
	std::map<v3s16, MapBlock*> *changed_blocks)
{
	v3s16 bpmin = data->blockpos_min;
	v3s16 bpmax = data->blockpos_max;

	v3s16 extra_borders(1, 1, 1);

	bool enable_mapgen_debug_info = m_emerge->enable_mapgen_debug_info;
	EMERGE_DBG_OUT("finishBlockMake(): " PP(bpmin) " - " PP(bpmax));

	/*
		Blit generated stuff to map
		NOTE: blitBackAll adds nearly everything to changed_blocks
	*/
	data->vmanip->blitBackAll(changed_blocks);

	EMERGE_DBG_OUT("finishBlockMake: changed_blocks.size()="
		<< changed_blocks->size());

	/*
		Copy transforming liquid information
	*/
	while (data->transforming_liquid.size()) {
		m_transforming_liquid.push_back(data->transforming_liquid.front());
		data->transforming_liquid.pop_front();
	}

	for (auto &changed_block : *changed_blocks) {
		MapBlock *block = changed_block.second;
		if (!block)
			continue;
		/*
			Update day/night difference cache of the MapBlocks
		*/
		block->expireDayNightDiff();
		/*
			Set block as modified
		*/
		block->raiseModified(MOD_STATE_WRITE_NEEDED,
			MOD_REASON_EXPIRE_DAYNIGHTDIFF);
	}

	/*
		Set central blocks as generated
	*/
	for (s16 x = bpmin.X; x <= bpmax.X; x++)
	for (s16 z = bpmin.Z; z <= bpmax.Z; z++)
	for (s16 y = bpmin.Y; y <= bpmax.Y; y++) {
		MapBlock *block = getBlockNoCreateNoEx(v3s16(x, y, z));
		if (!block)
			continue;

		block->setGenerated(true);
	}

	/*
		Save changed parts of map
		NOTE: Will be saved later.
	*/
	//save(MOD_STATE_WRITE_AT_UNLOAD);
}

MapSector *ServerMap::createSector(v2s16 p2d)
{
	/*
		Check if it exists already in memory
	*/
	MapSector *sector = getSectorNoGenerateNoEx(p2d);
	if (sector)
		return sector;

	/*
		Do not create over max mapgen limit
	*/
	const s16 max_limit_bp = MAX_MAP_GENERATION_LIMIT / MAP_BLOCKSIZE;
	if (p2d.X < -max_limit_bp ||
			p2d.X >  max_limit_bp ||
			p2d.Y < -max_limit_bp ||
			p2d.Y >  max_limit_bp)
		throw InvalidPositionException("createSector(): pos. over max mapgen limit");

	/*
		Generate blank sector
	*/

	sector = new MapSector(this, p2d, m_gamedef);

	// Sector position on map in nodes
	//v2s16 nodepos2d = p2d * MAP_BLOCKSIZE;

	/*
		Insert to container
	*/
	m_sectors[p2d] = sector;

	return sector;
}

#if 0
/*
	This is a quick-hand function for calling makeBlock().
*/
MapBlock * ServerMap::generateBlock(
		v3s16 p,
		std::map<v3s16, MapBlock*> &modified_blocks
)
{
	bool enable_mapgen_debug_info = g_settings->getBool("enable_mapgen_debug_info");

	TimeTaker timer("generateBlock");

	//MapBlock *block = original_dummy;

	v2s16 p2d(p.X, p.Z);
	v2s16 p2d_nodes = p2d * MAP_BLOCKSIZE;

	/*
		Do not generate over-limit
	*/
	if(blockpos_over_limit(p))
	{
		infostream<<FUNCTION_NAME<<": Block position over limit"<<std::endl;
		throw InvalidPositionException("generateBlock(): pos. over limit");
	}

	/*
		Create block make data
	*/
	BlockMakeData data;
	initBlockMake(&data, p);

	/*
		Generate block
	*/
	{
		TimeTaker t("mapgen::make_block()");
		mapgen->makeChunk(&data);
		//mapgen::make_block(&data);

		if(enable_mapgen_debug_info == false)
			t.stop(true); // Hide output
	}

	/*
		Blit data back on map, update lighting, add mobs and whatever this does
	*/
	finishBlockMake(&data, modified_blocks);

	/*
		Get central block
	*/
	MapBlock *block = getBlockNoCreateNoEx(p);

#if 0
	/*
		Check result
	*/
	if(block)
	{
		bool erroneus_content = false;
		for(s16 z0=0; z0<MAP_BLOCKSIZE; z0++)
		for(s16 y0=0; y0<MAP_BLOCKSIZE; y0++)
		for(s16 x0=0; x0<MAP_BLOCKSIZE; x0++)
		{
			v3s16 p(x0,y0,z0);
			MapNode n = block->getNode(p);
			if(n.getContent() == CONTENT_IGNORE)
			{
				infostream<<"CONTENT_IGNORE at "
						<<"("<<p.X<<","<<p.Y<<","<<p.Z<<")"
						<<std::endl;
				erroneus_content = true;
				assert(0);
			}
		}
		if(erroneus_content)
		{
			assert(0);
		}
	}
#endif

#if 0
	/*
		Generate a completely empty block
	*/
	if(block)
	{
		for(s16 z0=0; z0<MAP_BLOCKSIZE; z0++)
		for(s16 x0=0; x0<MAP_BLOCKSIZE; x0++)
		{
			for(s16 y0=0; y0<MAP_BLOCKSIZE; y0++)
			{
				MapNode n;
				n.setContent(CONTENT_AIR);
				block->setNode(v3s16(x0,y0,z0), n);
			}
		}
	}
#endif

	if(enable_mapgen_debug_info == false)
		timer.stop(true); // Hide output

	return block;
}
#endif

MapBlock * ServerMap::createBlock(v3s16 p)
{
	/*
		Do not create over max mapgen limit
	*/
	if (blockpos_over_max_limit(p))
		throw InvalidPositionException("createBlock(): pos. over max mapgen limit");

	v2s16 p2d(p.X, p.Z);
	s16 block_y = p.Y;
	/*
		This will create or load a sector if not found in memory.
		If block exists on disk, it will be loaded.

		NOTE: On old save formats, this will be slow, as it generates
		      lighting on blocks for them.
	*/
	MapSector *sector;
	try {
		sector = createSector(p2d);
	} catch (InvalidPositionException &e) {
		infostream<<"createBlock: createSector() failed"<<std::endl;
		throw e;
	}

	/*
		Try to get a block from the sector
	*/

	MapBlock *block = sector->getBlockNoCreateNoEx(block_y);
	if (block) {
		if(block->isDummy())
			block->unDummify();
		return block;
	}
	// Create blank
	block = sector->createBlankBlock(block_y);

	return block;
}

MapBlock * ServerMap::emergeBlock(v3s16 p, bool create_blank)
{
	{
		MapBlock *block = getBlockNoCreateNoEx(p);
		if (block && !block->isDummy())
			return block;
	}

	{
		MapBlock *block = loadBlock(p);
		if(block)
			return block;
	}

	if (create_blank) {
		MapSector *sector = createSector(v2s16(p.X, p.Z));
		MapBlock *block = sector->createBlankBlock(p.Y);

		return block;
	}

	return NULL;
}

MapBlock *ServerMap::getBlockOrEmerge(v3s16 p3d)
{
	MapBlock *block = getBlockNoCreateNoEx(p3d);
	if (block == NULL)
		m_emerge->enqueueBlockEmerge(PEER_ID_INEXISTENT, p3d, false);

	return block;
}

// N.B.  This requires no synchronization, since data will not be modified unless
// the VoxelManipulator being updated belongs to the same thread.
void ServerMap::updateVManip(v3s16 pos)
{
	Mapgen *mg = m_emerge->getCurrentMapgen();
	if (!mg)
		return;

	MMVManip *vm = mg->vm;
	if (!vm)
		return;

	if (!vm->m_area.contains(pos))
		return;

	s32 idx = vm->m_area.index(pos);
	vm->m_data[idx] = getNodeNoEx(pos);
	vm->m_flags[idx] &= ~VOXELFLAG_NO_DATA;

	vm->m_is_dirty = true;
}

s16 ServerMap::findGroundLevel(v2s16 p2d)
{
#if 0
	/*
		Uh, just do something random...
	*/
	// Find existing map from top to down
	s16 max=63;
	s16 min=-64;
	v3s16 p(p2d.X, max, p2d.Y);
	for(; p.Y>min; p.Y--)
	{
		MapNode n = getNodeNoEx(p);
		if(n.getContent() != CONTENT_IGNORE)
			break;
	}
	if(p.Y == min)
		goto plan_b;
	// If this node is not air, go to plan b
	if(getNodeNoEx(p).getContent() != CONTENT_AIR)
		goto plan_b;
	// Search existing walkable and return it
	for(; p.Y>min; p.Y--)
	{
		MapNode n = getNodeNoEx(p);
		if(content_walkable(n.d) && n.getContent() != CONTENT_IGNORE)
			return p.Y;
	}

	// Move to plan b
plan_b:
#endif

	/*
		Determine from map generator noise functions
	*/

	s16 level = m_emerge->getGroundLevelAtPoint(p2d);
	return level;

	//double level = base_rock_level_2d(m_seed, p2d) + AVERAGE_MUD_AMOUNT;
	//return (s16)level;
}

bool ServerMap::loadFromFolders() {
	if (!dbase->initialized() &&
			!fs::PathExists(m_savedir + DIR_DELIM + "map.sqlite"))
		return true;
	return false;
}

void ServerMap::createDirs(std::string path)
{
	if (!fs::CreateAllDirs(path)) {
		m_dout<<"ServerMap: Failed to create directory "
				<<"\""<<path<<"\""<<std::endl;
		throw BaseException("ServerMap failed to create directory");
	}
}

std::string ServerMap::getSectorDir(v2s16 pos, int layout)
{
	char cc[9];
	switch(layout)
	{
		case 1:
			porting::mt_snprintf(cc, sizeof(cc), "%.4x%.4x",
				(unsigned int) pos.X & 0xffff,
				(unsigned int) pos.Y & 0xffff);

			return m_savedir + DIR_DELIM + "sectors" + DIR_DELIM + cc;
		case 2:
			porting::mt_snprintf(cc, sizeof(cc), (std::string("%.3x") + DIR_DELIM + "%.3x").c_str(),
				(unsigned int) pos.X & 0xfff,
				(unsigned int) pos.Y & 0xfff);

			return m_savedir + DIR_DELIM + "sectors2" + DIR_DELIM + cc;
		default:
			assert(false);
			return "";
	}
}

v2s16 ServerMap::getSectorPos(const std::string &dirname)
{
	unsigned int x = 0, y = 0;
	int r;
	std::string component;
	fs::RemoveLastPathComponent(dirname, &component, 1);
	if(component.size() == 8)
	{
		// Old layout
		r = sscanf(component.c_str(), "%4x%4x", &x, &y);
	}
	else if(component.size() == 3)
	{
		// New layout
		fs::RemoveLastPathComponent(dirname, &component, 2);
		r = sscanf(component.c_str(), (std::string("%3x") + DIR_DELIM + "%3x").c_str(), &x, &y);
		// Sign-extend the 12 bit values up to 16 bits...
		if(x & 0x800) x |= 0xF000;
		if(y & 0x800) y |= 0xF000;
	}
	else
	{
		r = -1;
	}

	FATAL_ERROR_IF(r != 2, "getSectorPos()");
	v2s16 pos((s16)x, (s16)y);
	return pos;
}

v3s16 ServerMap::getBlockPos(const std::string &sectordir, const std::string &blockfile)
{
	v2s16 p2d = getSectorPos(sectordir);

	if(blockfile.size() != 4){
		throw InvalidFilenameException("Invalid block filename");
	}
	unsigned int y;
	int r = sscanf(blockfile.c_str(), "%4x", &y);
	if(r != 1)
		throw InvalidFilenameException("Invalid block filename");
	return v3s16(p2d.X, y, p2d.Y);
}

std::string ServerMap::getBlockFilename(v3s16 p)
{
	char cc[5];
	porting::mt_snprintf(cc, sizeof(cc), "%.4x", (unsigned int)p.Y&0xffff);
	return cc;
}

void ServerMap::save(ModifiedState save_level)
{
	if (!m_map_saving_enabled) {
		warningstream<<"Not saving map, saving disabled."<<std::endl;
		return;
	}

	if(save_level == MOD_STATE_CLEAN)
		infostream<<"ServerMap: Saving whole map, this can take time."
				<<std::endl;

	if (m_map_metadata_changed || save_level == MOD_STATE_CLEAN) {
		if (settings_mgr.saveMapMeta())
			m_map_metadata_changed = false;
	}

	// Profile modified reasons
	Profiler modprofiler;

	u32 block_count = 0;
	u32 block_count_all = 0; // Number of blocks in memory

	// Don't do anything with sqlite unless something is really saved
	bool save_started = false;

	for (auto &sector_it : m_sectors) {
		MapSector *sector = sector_it.second;

		MapBlockVect blocks;
		sector->getBlocks(blocks);

		for (MapBlock *block : blocks) {
			block_count_all++;

			if(block->getModified() >= (u32)save_level) {
				// Lazy beginSave()
				if(!save_started) {
					beginSave();
					save_started = true;
				}

				modprofiler.add(block->getModifiedReasonString(), 1);

				saveBlock(block);
				block_count++;
			}
		}
	}

	if(save_started)
		endSave();

	/*
		Only print if something happened or saved whole map
	*/
	if(save_level == MOD_STATE_CLEAN
			|| block_count != 0) {
		infostream<<"ServerMap: Written: "
				<<block_count<<" block files"
				<<", "<<block_count_all<<" blocks in memory."
				<<std::endl;
		PrintInfo(infostream); // ServerMap/ClientMap:
		infostream<<"Blocks modified by: "<<std::endl;
		modprofiler.print(infostream);
	}
}

void ServerMap::listAllLoadableBlocks(std::vector<v3s16> &dst)
{
	if (loadFromFolders()) {
		errorstream << "Map::listAllLoadableBlocks(): Result will be missing "
				<< "all blocks that are stored in flat files." << std::endl;
	}
	dbase->listAllLoadableBlocks(dst);
	if (dbase_ro)
		dbase_ro->listAllLoadableBlocks(dst);
}

void ServerMap::listAllLoadedBlocks(std::vector<v3s16> &dst)
{
	for (auto &sector_it : m_sectors) {
		MapSector *sector = sector_it.second;

		MapBlockVect blocks;
		sector->getBlocks(blocks);

		for (MapBlock *block : blocks) {
			v3s16 p = block->getPos();
			dst.push_back(p);
		}
	}
}

MapDatabase *ServerMap::createDatabase(
	const std::string &name,
	const std::string &savedir,
	Settings &conf)
{
	if (name == "sqlite3")
		return new MapDatabaseSQLite3(savedir);
	if (name == "dummy")
		return new Database_Dummy();
	#if USE_LEVELDB
	if (name == "leveldb")
		return new Database_LevelDB(savedir);
	#endif
	#if USE_REDIS
	if (name == "redis")
		return new Database_Redis(conf);
	#endif
	#if USE_POSTGRESQL
	if (name == "postgresql") {
		std::string connect_string;
		conf.getNoEx("pgsql_connection", connect_string);
		return new MapDatabasePostgreSQL(connect_string);
	}
	#endif

	throw BaseException(std::string("Database backend ") + name + " not supported.");
}

void ServerMap::beginSave()
{
	dbase->beginSave();
}

void ServerMap::endSave()
{
	dbase->endSave();
}

bool ServerMap::saveBlock(MapBlock *block)
{
	return saveBlock(block, dbase);
}

bool ServerMap::saveBlock(MapBlock *block, MapDatabase *db)
{
	v3s16 p3d = block->getPos();

	// Dummy blocks are not written
	if (block->isDummy()) {
		warningstream << "saveBlock: Not writing dummy block "
			<< PP(p3d) << std::endl;
		return true;
	}

	// Format used for writing
	u8 version = SER_FMT_VER_HIGHEST_WRITE;

	/*
		[0] u8 serialization version
		[1] data
	*/
	std::ostringstream o(std::ios_base::binary);
	o.write((char*) &version, 1);
	block->serialize(o, version, true);

	bool ret = db->saveBlock(p3d, o.str());
	if (ret) {
		// We just wrote it to the disk so clear modified flag
		block->resetModified();
	}
	return ret;
}

void ServerMap::loadBlock(const std::string &sectordir, const std::string &blockfile,
		MapSector *sector, bool save_after_load)
{
	std::string fullpath = sectordir + DIR_DELIM + blockfile;
	try {
		std::ifstream is(fullpath.c_str(), std::ios_base::binary);
		if (!is.good())
			throw FileNotGoodException("Cannot open block file");

		v3s16 p3d = getBlockPos(sectordir, blockfile);
		v2s16 p2d(p3d.X, p3d.Z);

		assert(sector->getPos() == p2d);

		u8 version = SER_FMT_VER_INVALID;
		is.read((char*)&version, 1);

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

		/*u32 block_size = MapBlock::serializedLength(version);
		SharedBuffer<u8> data(block_size);
		is.read((char*)*data, block_size);*/

		// This will always return a sector because we're the server
		//MapSector *sector = emergeSector(p2d);

		MapBlock *block = NULL;
		bool created_new = false;
		block = sector->getBlockNoCreateNoEx(p3d.Y);
		if(block == NULL)
		{
			block = sector->createBlankBlockNoInsert(p3d.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);
			ReflowScan scanner(this, m_emerge->ndef);
			scanner.scan(block, &m_transforming_liquid);
		}

		/*
			Save blocks loaded in old format in new format
		*/

		if(version < SER_FMT_VER_HIGHEST_WRITE || save_after_load)
		{
			saveBlock(block);

			// Should be in database now, so delete the old file
			fs::RecursiveDelete(fullpath);
		}

		// We just loaded it from the disk, so it's up-to-date.
		block->resetModified();

	}
	catch(SerializationError &e)
	{
		warningstream<<"Invalid block data on disk "
				<<"fullpath="<<fullpath
				<<" (SerializationError). "
				<<"what()="<<e.what()
				<<std::endl;
				// Ignoring. A new one will be generated.
		abort();

		// TODO: Backup file; name is in fullpath.
	}
}

void ServerMap::loadBlock(std::string *blob, v3s16 p3d, MapSector *sector, bool save_after_load)
{
	try {
		std::istringstream is(*blob, 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(p3d.Y);
		if(block == NULL)
		{
			block = sector->createBlankBlockNoInsert(p3d.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);
			ReflowScan scanner(this, m_emerge->ndef);
			scanner.scan(block, &m_transforming_liquid);
		}

		/*
			Save blocks loaded in old format in new format
		*/

		//if(version < SER_FMT_VER_HIGHEST_READ || 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"
				<<" ("<<p3d.X<<","<<p3d.Y<<","<<p3d.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");
		}
	}
}

MapBlock* ServerMap::loadBlock(v3s16 blockpos)
{
	bool created_new = (getBlockNoCreateNoEx(blockpos) == NULL);

	v2s16 p2d(blockpos.X, blockpos.Z);

	std::string ret;
	dbase->loadBlock(blockpos, &ret);
	if (!ret.empty()) {
		loadBlock(&ret, blockpos, createSector(p2d), false);
	} else if (dbase_ro) {
		dbase_ro->loadBlock(blockpos, &ret);
		if (!ret.empty()) {
			loadBlock(&ret, blockpos, createSector(p2d), false);
		}
	} else {
		// Not found in database, try the files

		// The directory layout we're going to load from.
		//  1 - original sectors/xxxxzzzz/
		//  2 - new sectors2/xxx/zzz/
		//  If we load from anything but the latest structure, we will
		//  immediately save to the new one, and remove the old.
		std::string sectordir1 = getSectorDir(p2d, 1);
		std::string sectordir;
		if (fs::PathExists(sectordir1)) {
			sectordir = sectordir1;
		} else {
			sectordir = getSectorDir(p2d, 2);
		}

		/*
		Make sure sector is loaded
		 */

		MapSector *sector = getSectorNoGenerateNoEx(p2d);

		/*
		Make sure file exists
		 */

		std::string blockfilename = getBlockFilename(blockpos);
		if (!fs::PathExists(sectordir + DIR_DELIM + blockfilename))
			return NULL;

		/*
		Load block and save it to the database
		 */
		loadBlock(sectordir, blockfilename, sector, true);
	}

	MapBlock *block = getBlockNoCreateNoEx(blockpos);
	if (created_new && (block != NULL)) {
		std::map<v3s16, MapBlock*> modified_blocks;
		// Fix lighting if necessary
		voxalgo::update_block_border_lighting(this, block, modified_blocks);
		if (!modified_blocks.empty()) {
			//Modified lighting, send event
			MapEditEvent event;
			event.type = MEET_OTHER;
			std::map<v3s16, MapBlock *>::iterator it;
			for (it = modified_blocks.begin();
					it != modified_blocks.end(); ++it)
				event.modified_blocks.insert(it->first);
			dispatchEvent(&event);
		}
	}
	return block;
}

bool ServerMap::deleteBlock(v3s16 blockpos)
{
	if (!dbase->deleteBlock(blockpos))
		return false;

	MapBlock *block = getBlockNoCreateNoEx(blockpos);
	if (block) {
		v2s16 p2d(blockpos.X, blockpos.Z);
		MapSector *sector = getSectorNoGenerateNoEx(p2d);
		if (!sector)
			return false;
		sector->deleteBlock(block);
	}

	return true;
}

void ServerMap::PrintInfo(std::ostream &out)
{
	out<<"ServerMap: ";
}

bool ServerMap::repairBlockLight(v3s16 blockpos,
	std::map<v3s16, MapBlock *> *modified_blocks)
{
	MapBlock *block = emergeBlock(blockpos, false);
	if (!block || !block->isGenerated())
		return false;
	voxalgo::repair_block_light(this, block, modified_blocks);
	return true;
}

MMVManip::MMVManip(Map *map):
		VoxelManipulator(),
		m_map(map)
{
}

void MMVManip::initialEmerge(v3s16 blockpos_min, v3s16 blockpos_max,
	bool load_if_inexistent)
{
	TimeTaker timer1("initialEmerge", &emerge_time);

	// Units of these are MapBlocks
	v3s16 p_min = blockpos_min;
	v3s16 p_max = blockpos_max;

	VoxelArea block_area_nodes
			(p_min*MAP_BLOCKSIZE, (p_max+1)*MAP_BLOCKSIZE-v3s16(1,1,1));

	u32 size_MB = block_area_nodes.getVolume()*4/1000000;
	if(size_MB >= 1)
	{
		infostream<<"initialEmerge: area: ";
		block_area_nodes.print(infostream);
		infostream<<" ("<<size_MB<<"MB)";
		infostream<<std::endl;
	}

	addArea(block_area_nodes);

	for(s32 z=p_min.Z; z<=p_max.Z; z++)
	for(s32 y=p_min.Y; y<=p_max.Y; y++)
	for(s32 x=p_min.X; x<=p_max.X; x++)
	{
		u8 flags = 0;
		MapBlock *block;
		v3s16 p(x,y,z);
		std::map<v3s16, u8>::iterator n;
		n = m_loaded_blocks.find(p);
		if(n != m_loaded_blocks.end())
			continue;

		bool block_data_inexistent = false;
		try
		{
			TimeTaker timer2("emerge load", &emerge_load_time);

			block = m_map->getBlockNoCreate(p);
			if(block->isDummy())
				block_data_inexistent = true;
			else
				block->copyTo(*this);
		}
		catch(InvalidPositionException &e)
		{
			block_data_inexistent = true;
		}

		if(block_data_inexistent)
		{

			if (load_if_inexistent && !blockpos_over_max_limit(p)) {
				ServerMap *svrmap = (ServerMap *)m_map;
				block = svrmap->emergeBlock(p, false);
				if (block == NULL)
					block = svrmap->createBlock(p);
				block->copyTo(*this);
			} else {
				flags |= VMANIP_BLOCK_DATA_INEXIST;

				/*
					Mark area inexistent
				*/
				VoxelArea a(p*MAP_BLOCKSIZE, (p+1)*MAP_BLOCKSIZE-v3s16(1,1,1));
				// Fill with VOXELFLAG_NO_DATA
				for(s32 z=a.MinEdge.Z; z<=a.MaxEdge.Z; z++)
				for(s32 y=a.MinEdge.Y; y<=a.MaxEdge.Y; y++)
				{
					s32 i = m_area.index(a.MinEdge.X,y,z);
					memset(&m_flags[i], VOXELFLAG_NO_DATA, MAP_BLOCKSIZE);
				}
			}
		}
		/*else if (block->getNode(0, 0, 0).getContent() == CONTENT_IGNORE)
		{
			// Mark that block was loaded as blank
			flags |= VMANIP_BLOCK_CONTAINS_CIGNORE;
		}*/

		m_loaded_blocks[p] = flags;
	}

	m_is_dirty = false;
}

void MMVManip::blitBackAll(std::map<v3s16, MapBlock*> *modified_blocks,
	bool overwrite_generated)
{
	if(m_area.getExtent() == v3s16(0,0,0))
		return;

	/*
		Copy data of all blocks
	*/
	for (auto &loaded_block : m_loaded_blocks) {
		v3s16 p = loaded_block.first;
		MapBlock *block = m_map->getBlockNoCreateNoEx(p);
		bool existed = !(loaded_block.second & VMANIP_BLOCK_DATA_INEXIST);
		if (!existed || (block == NULL) ||
			(!overwrite_generated && block->isGenerated()))
			continue;

		block->copyFrom(*this);
		block->raiseModified(MOD_STATE_WRITE_NEEDED, MOD_REASON_VMANIP);

		if(modified_blocks)
			(*modified_blocks)[p] = block;
	}
}

//END