]> git.lizzy.rs Git - minetest.git/blobdiff - src/map.cpp
Allow an optional readonly base database (#7544)
[minetest.git] / src / map.cpp
index 48585a17039456bae65fd2425e734903cf45b582..0114867e09e23478748f53e6da3cda0d69cbc7cf 100644 (file)
@@ -20,9 +20,9 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "map.h"
 #include "mapsector.h"
 #include "mapblock.h"
-#include "main.h"
 #include "filesys.h"
 #include "voxel.h"
+#include "voxelalgorithms.h"
 #include "porting.h"
 #include "serialization.h"
 #include "nodemetadata.h"
@@ -32,42 +32,31 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "nodedef.h"
 #include "gamedef.h"
 #include "util/directiontables.h"
-#include "util/mathconstants.h"
+#include "util/basic_macros.h"
 #include "rollback_interface.h"
 #include "environment.h"
+#include "reflowscan.h"
 #include "emerge.h"
-#include "mapgen_v6.h"
-#include "mg_biome.h"
+#include "mapgen/mapgen_v6.h"
+#include "mapgen/mg_biome.h"
 #include "config.h"
 #include "server.h"
-#include "database.h"
-#include "database-dummy.h"
-#include "database-sqlite3.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-leveldb.h"
+#include "database/database-leveldb.h"
 #endif
 #if USE_REDIS
-#include "database-redis.h"
+#include "database/database-redis.h"
+#endif
+#if USE_POSTGRESQL
+#include "database/database-postgresql.h"
 #endif
 
-#define PP(x) "("<<(x).X<<","<<(x).Y<<","<<(x).Z<<")"
-
-/*
-       SQLite format specification:
-       - Initially only replaces sectors/ and sectors2/
-
-       If map.sqlite does not exist in the save dir
-       or the block was not found in the database
-       the map will try to load from sectors folder.
-       In either case, map.sqlite will be created
-       and all future saves will save there.
-
-       Structure of map.sqlite:
-       Tables:
-               blocks
-                       (PK) INT pos
-                       BLOB data
-*/
 
 /*
        Map
@@ -76,11 +65,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 Map::Map(std::ostream &dout, IGameDef *gamedef):
        m_dout(dout),
        m_gamedef(gamedef),
-       m_sector_cache(NULL),
-       m_transforming_liquid_loop_count_multiplier(1.0f),
-       m_unprocessed_count(0),
-       m_inc_trending_up_start_time(0),
-       m_queue_size_timer_started(false)
+       m_nodedef(gamedef->ndef())
 {
 }
 
@@ -89,10 +74,8 @@ Map::~Map()
        /*
                Free all MapSectors
        */
-       for(std::map<v2s16, MapSector*>::iterator i = m_sectors.begin();
-               i != m_sectors.end(); ++i)
-       {
-               delete i->second;
+       for (auto &sector : m_sectors) {
+               delete sector.second;
        }
 }
 
@@ -108,11 +91,8 @@ void Map::removeEventReceiver(MapEventReceiver *event_receiver)
 
 void Map::dispatchEvent(MapEditEvent *event)
 {
-       for(std::set<MapEventReceiver*>::iterator
-                       i = m_event_receivers.begin();
-                       i != m_event_receivers.end(); ++i)
-       {
-               (*i)->onMapEditEvent(event);
+       for (MapEventReceiver *event_receiver : m_event_receivers) {
+               event_receiver->onMapEditEvent(event);
        }
 }
 
@@ -125,7 +105,7 @@ MapSector * Map::getSectorNoGenerateNoExNoLock(v2s16 p)
 
        std::map<v2s16, MapSector*>::iterator n = m_sectors.find(p);
 
-       if(n == m_sectors.end())
+       if (n == m_sectors.end())
                return NULL;
 
        MapSector *sector = n->second;
@@ -185,7 +165,7 @@ bool Map::isNodeUnderground(v3s16 p)
 bool Map::isValidPosition(v3s16 p)
 {
        v3s16 blockpos = getNodeBlockPos(p);
-       MapBlock *block = getBlockNoCreate(blockpos);
+       MapBlock *block = getBlockNoCreateNoEx(blockpos);
        return (block != NULL);
 }
 
@@ -197,7 +177,7 @@ MapNode Map::getNodeNoEx(v3s16 p, bool *is_valid_position)
        if (block == NULL) {
                if (is_valid_position != NULL)
                        *is_valid_position = false;
-               return MapNode(CONTENT_IGNORE);
+               return {CONTENT_IGNORE};
        }
 
        v3s16 relpos = p - blockpos*MAP_BLOCKSIZE;
@@ -238,1039 +218,44 @@ void Map::setNode(v3s16 p, MapNode & n)
                bool temp_bool;
                errorstream<<"Map::setNode(): Not allowing to place CONTENT_IGNORE"
                                <<" while trying to replace \""
-                               <<m_gamedef->ndef()->get(block->getNodeNoCheck(relpos, &temp_bool)).name
+                               <<m_nodedef->get(block->getNodeNoCheck(relpos, &temp_bool)).name
                                <<"\" at "<<PP(p)<<" (block "<<PP(blockpos)<<")"<<std::endl;
-               debug_stacks_print_to(infostream);
                return;
        }
        block->setNodeNoCheck(relpos, n);
 }
 
-
-/*
-       Goes recursively through the neighbours of the node.
-
-       Alters only transparent nodes.
-
-       If the lighting of the neighbour is lower than the lighting of
-       the node was (before changing it to 0 at the step before), the
-       lighting of the neighbour is set to 0 and then the same stuff
-       repeats for the neighbour.
-
-       The ending nodes of the routine are stored in light_sources.
-       This is useful when a light is removed. In such case, this
-       routine can be called for the light node and then again for
-       light_sources to re-light the area without the removed light.
-
-       values of from_nodes are lighting values.
-*/
-void Map::unspreadLight(enum LightBank bank,
-               std::map<v3s16, u8> & from_nodes,
-               std::set<v3s16> & light_sources,
-               std::map<v3s16, MapBlock*>  & modified_blocks)
-{
-       INodeDefManager *nodemgr = m_gamedef->ndef();
-
-       v3s16 dirs[6] = {
-               v3s16(0,0,1), // back
-               v3s16(0,1,0), // top
-               v3s16(1,0,0), // right
-               v3s16(0,0,-1), // front
-               v3s16(0,-1,0), // bottom
-               v3s16(-1,0,0), // left
-       };
-
-       if(from_nodes.empty())
-               return;
-
-       u32 blockchangecount = 0;
-
-       std::map<v3s16, u8> unlighted_nodes;
-
-       /*
-               Initialize block cache
-       */
-       v3s16 blockpos_last;
-       MapBlock *block = NULL;
-       // Cache this a bit, too
-       bool block_checked_in_modified = false;
-
-       for(std::map<v3s16, u8>::iterator j = from_nodes.begin();
-               j != from_nodes.end(); ++j)
-       {
-               v3s16 pos = j->first;
-               v3s16 blockpos = getNodeBlockPos(pos);
-
-               // Only fetch a new block if the block position has changed
-               try{
-                       if(block == NULL || blockpos != blockpos_last){
-                               block = getBlockNoCreate(blockpos);
-                               blockpos_last = blockpos;
-
-                               block_checked_in_modified = false;
-                               blockchangecount++;
-                       }
-               }
-               catch(InvalidPositionException &e)
-               {
-                       continue;
-               }
-
-               if(block->isDummy())
-                       continue;
-
-               // Calculate relative position in block
-               //v3s16 relpos = pos - blockpos_last * MAP_BLOCKSIZE;
-
-               // Get node straight from the block
-               //MapNode n = block->getNode(relpos);
-
-               u8 oldlight = j->second;
-
-               // Loop through 6 neighbors
-               for(u16 i=0; i<6; i++)
-               {
-                       // Get the position of the neighbor node
-                       v3s16 n2pos = pos + dirs[i];
-
-                       // Get the block where the node is located
-                       v3s16 blockpos = getNodeBlockPos(n2pos);
-
-                       // Only fetch a new block if the block position has changed
-                       try {
-                               if(block == NULL || blockpos != blockpos_last){
-                                       block = getBlockNoCreate(blockpos);
-                                       blockpos_last = blockpos;
-
-                                       block_checked_in_modified = false;
-                                       blockchangecount++;
-                               }
-                       }
-                       catch(InvalidPositionException &e) {
-                               continue;
-                       }
-
-                       // Calculate relative position in block
-                       v3s16 relpos = n2pos - blockpos * MAP_BLOCKSIZE;
-                       // Get node straight from the block
-                       bool is_valid_position;
-                       MapNode n2 = block->getNode(relpos, &is_valid_position);
-                       if (!is_valid_position)
-                               continue;
-
-                       bool changed = false;
-
-                       //TODO: Optimize output by optimizing light_sources?
-
-                       /*
-                               If the neighbor is dimmer than what was specified
-                               as oldlight (the light of the previous node)
-                       */
-                       if(n2.getLight(bank, nodemgr) < oldlight)
-                       {
-                               /*
-                                       And the neighbor is transparent and it has some light
-                               */
-                               if(nodemgr->get(n2).light_propagates
-                                               && n2.getLight(bank, nodemgr) != 0)
-                               {
-                                       /*
-                                               Set light to 0 and add to queue
-                                       */
-
-                                       u8 current_light = n2.getLight(bank, nodemgr);
-                                       n2.setLight(bank, 0, nodemgr);
-                                       block->setNode(relpos, n2);
-
-                                       unlighted_nodes[n2pos] = current_light;
-                                       changed = true;
-
-                                       /*
-                                               Remove from light_sources if it is there
-                                               NOTE: This doesn't happen nearly at all
-                                       */
-                                       /*if(light_sources.find(n2pos))
-                                       {
-                                               infostream<<"Removed from light_sources"<<std::endl;
-                                               light_sources.remove(n2pos);
-                                       }*/
-                               }
-
-                               /*// DEBUG
-                               if(light_sources.find(n2pos) != NULL)
-                                       light_sources.remove(n2pos);*/
-                       }
-                       else{
-                               light_sources.insert(n2pos);
-                       }
-
-                       // Add to modified_blocks
-                       if(changed == true && block_checked_in_modified == false)
-                       {
-                               // If the block is not found in modified_blocks, add.
-                               if(modified_blocks.find(blockpos) == modified_blocks.end())
-                               {
-                                       modified_blocks[blockpos] = block;
-                               }
-                               block_checked_in_modified = true;
-                       }
-               }
-       }
-
-       /*infostream<<"unspreadLight(): Changed block "
-                       <<blockchangecount<<" times"
-                       <<" for "<<from_nodes.size()<<" nodes"
-                       <<std::endl;*/
-
-       if(!unlighted_nodes.empty())
-               unspreadLight(bank, unlighted_nodes, light_sources, modified_blocks);
-}
-
-/*
-       A single-node wrapper of the above
-*/
-void Map::unLightNeighbors(enum LightBank bank,
-               v3s16 pos, u8 lightwas,
-               std::set<v3s16> & light_sources,
-               std::map<v3s16, MapBlock*>  & modified_blocks)
-{
-       std::map<v3s16, u8> from_nodes;
-       from_nodes[pos] = lightwas;
-
-       unspreadLight(bank, from_nodes, light_sources, modified_blocks);
-}
-
-/*
-       Lights neighbors of from_nodes, collects all them and then
-       goes on recursively.
-*/
-void Map::spreadLight(enum LightBank bank,
-               std::set<v3s16> & from_nodes,
-               std::map<v3s16, MapBlock*> & modified_blocks)
-{
-       INodeDefManager *nodemgr = m_gamedef->ndef();
-
-       const v3s16 dirs[6] = {
-               v3s16(0,0,1), // back
-               v3s16(0,1,0), // top
-               v3s16(1,0,0), // right
-               v3s16(0,0,-1), // front
-               v3s16(0,-1,0), // bottom
-               v3s16(-1,0,0), // left
-       };
-
-       if(from_nodes.empty())
-               return;
-
-       u32 blockchangecount = 0;
-
-       std::set<v3s16> lighted_nodes;
-
-       /*
-               Initialize block cache
-       */
-       v3s16 blockpos_last;
-       MapBlock *block = NULL;
-       // Cache this a bit, too
-       bool block_checked_in_modified = false;
-
-       for(std::set<v3s16>::iterator j = from_nodes.begin();
-               j != from_nodes.end(); ++j)
-       {
-               v3s16 pos = *j;
-               v3s16 blockpos = getNodeBlockPos(pos);
-
-               // Only fetch a new block if the block position has changed
-               try {
-                       if(block == NULL || blockpos != blockpos_last){
-                               block = getBlockNoCreate(blockpos);
-                               blockpos_last = blockpos;
-
-                               block_checked_in_modified = false;
-                               blockchangecount++;
-                       }
-               }
-               catch(InvalidPositionException &e) {
-                       continue;
-               }
-
-               if(block->isDummy())
-                       continue;
-
-               // Calculate relative position in block
-               v3s16 relpos = pos - blockpos_last * MAP_BLOCKSIZE;
-
-               // Get node straight from the block
-               bool is_valid_position;
-               MapNode n = block->getNode(relpos, &is_valid_position);
-
-               u8 oldlight = is_valid_position ? n.getLight(bank, nodemgr) : 0;
-               u8 newlight = diminish_light(oldlight);
-
-               // Loop through 6 neighbors
-               for(u16 i=0; i<6; i++){
-                       // Get the position of the neighbor node
-                       v3s16 n2pos = pos + dirs[i];
-
-                       // Get the block where the node is located
-                       v3s16 blockpos = getNodeBlockPos(n2pos);
-
-                       // Only fetch a new block if the block position has changed
-                       try {
-                               if(block == NULL || blockpos != blockpos_last){
-                                       block = getBlockNoCreate(blockpos);
-                                       blockpos_last = blockpos;
-
-                                       block_checked_in_modified = false;
-                                       blockchangecount++;
-                               }
-                       }
-                       catch(InvalidPositionException &e) {
-                               continue;
-                       }
-
-                       // Calculate relative position in block
-                       v3s16 relpos = n2pos - blockpos * MAP_BLOCKSIZE;
-                       // Get node straight from the block
-                       MapNode n2 = block->getNode(relpos, &is_valid_position);
-                       if (!is_valid_position)
-                               continue;
-
-                       bool changed = false;
-                       /*
-                               If the neighbor is brighter than the current node,
-                               add to list (it will light up this node on its turn)
-                       */
-                       if(n2.getLight(bank, nodemgr) > undiminish_light(oldlight))
-                       {
-                               lighted_nodes.insert(n2pos);
-                               changed = true;
-                       }
-                       /*
-                               If the neighbor is dimmer than how much light this node
-                               would spread on it, add to list
-                       */
-                       if(n2.getLight(bank, nodemgr) < newlight)
-                       {
-                               if(nodemgr->get(n2).light_propagates)
-                               {
-                                       n2.setLight(bank, newlight, nodemgr);
-                                       block->setNode(relpos, n2);
-                                       lighted_nodes.insert(n2pos);
-                                       changed = true;
-                               }
-                       }
-
-                       // Add to modified_blocks
-                       if(changed == true && block_checked_in_modified == false)
-                       {
-                               // If the block is not found in modified_blocks, add.
-                               if(modified_blocks.find(blockpos) == modified_blocks.end())
-                               {
-                                       modified_blocks[blockpos] = block;
-                               }
-                               block_checked_in_modified = true;
-                       }
-               }
-       }
-
-       /*infostream<<"spreadLight(): Changed block "
-                       <<blockchangecount<<" times"
-                       <<" for "<<from_nodes.size()<<" nodes"
-                       <<std::endl;*/
-
-       if(!lighted_nodes.empty())
-               spreadLight(bank, lighted_nodes, modified_blocks);
-}
-
-/*
-       A single-node source variation of the above.
-*/
-void Map::lightNeighbors(enum LightBank bank,
-               v3s16 pos,
-               std::map<v3s16, MapBlock*> & modified_blocks)
-{
-       std::set<v3s16> from_nodes;
-       from_nodes.insert(pos);
-       spreadLight(bank, from_nodes, modified_blocks);
-}
-
-v3s16 Map::getBrightestNeighbour(enum LightBank bank, v3s16 p)
-{
-       INodeDefManager *nodemgr = m_gamedef->ndef();
-
-       v3s16 dirs[6] = {
-               v3s16(0,0,1), // back
-               v3s16(0,1,0), // top
-               v3s16(1,0,0), // right
-               v3s16(0,0,-1), // front
-               v3s16(0,-1,0), // bottom
-               v3s16(-1,0,0), // left
-       };
-
-       u8 brightest_light = 0;
-       v3s16 brightest_pos(0,0,0);
-       bool found_something = false;
-
-       // Loop through 6 neighbors
-       for(u16 i=0; i<6; i++){
-               // Get the position of the neighbor node
-               v3s16 n2pos = p + dirs[i];
-               MapNode n2;
-               bool is_valid_position;
-               n2 = getNodeNoEx(n2pos, &is_valid_position);
-               if (!is_valid_position)
-                       continue;
-
-               if(n2.getLight(bank, nodemgr) > brightest_light || found_something == false){
-                       brightest_light = n2.getLight(bank, nodemgr);
-                       brightest_pos = n2pos;
-                       found_something = true;
-               }
-       }
-
-       if(found_something == false)
-               throw InvalidPositionException();
-
-       return brightest_pos;
-}
-
-/*
-       Propagates sunlight down from a node.
-       Starting point gets sunlight.
-
-       Returns the lowest y value of where the sunlight went.
-
-       Mud is turned into grass in where the sunlight stops.
-*/
-s16 Map::propagateSunlight(v3s16 start,
-               std::map<v3s16, MapBlock*> & modified_blocks)
-{
-       INodeDefManager *nodemgr = m_gamedef->ndef();
-
-       s16 y = start.Y;
-       for(; ; y--)
-       {
-               v3s16 pos(start.X, y, start.Z);
-
-               v3s16 blockpos = getNodeBlockPos(pos);
-               MapBlock *block;
-               try{
-                       block = getBlockNoCreate(blockpos);
-               }
-               catch(InvalidPositionException &e)
-               {
-                       break;
-               }
-
-               v3s16 relpos = pos - blockpos*MAP_BLOCKSIZE;
-               bool is_valid_position;
-               MapNode n = block->getNode(relpos, &is_valid_position);
-               if (!is_valid_position)
-                       break;
-
-               if(nodemgr->get(n).sunlight_propagates)
-               {
-                       n.setLight(LIGHTBANK_DAY, LIGHT_SUN, nodemgr);
-                       block->setNode(relpos, n);
-
-                       modified_blocks[blockpos] = block;
-               }
-               else
-               {
-                       // Sunlight goes no further
-                       break;
-               }
-       }
-       return y + 1;
-}
-
-void Map::updateLighting(enum LightBank bank,
-               std::map<v3s16, MapBlock*> & a_blocks,
-               std::map<v3s16, MapBlock*> & modified_blocks)
-{
-       INodeDefManager *nodemgr = m_gamedef->ndef();
-
-       /*m_dout<<DTIME<<"Map::updateLighting(): "
-                       <<a_blocks.size()<<" blocks."<<std::endl;*/
-
-       //TimeTaker timer("updateLighting");
-
-       // For debugging
-       //bool debug=true;
-       //u32 count_was = modified_blocks.size();
-
-       std::map<v3s16, MapBlock*> blocks_to_update;
-
-       std::set<v3s16> light_sources;
-
-       std::map<v3s16, u8> unlight_from;
-
-       int num_bottom_invalid = 0;
-
-       {
-       //TimeTaker t("first stuff");
-
-       for(std::map<v3s16, MapBlock*>::iterator i = a_blocks.begin();
-               i != a_blocks.end(); ++i)
-       {
-               MapBlock *block = i->second;
-
-               for(;;)
-               {
-                       // Don't bother with dummy blocks.
-                       if(block->isDummy())
-                               break;
-
-                       v3s16 pos = block->getPos();
-                       v3s16 posnodes = block->getPosRelative();
-                       modified_blocks[pos] = block;
-                       blocks_to_update[pos] = block;
-
-                       /*
-                               Clear all light from block
-                       */
-                       for(s16 z=0; z<MAP_BLOCKSIZE; z++)
-                       for(s16 x=0; x<MAP_BLOCKSIZE; x++)
-                       for(s16 y=0; y<MAP_BLOCKSIZE; y++)
-                       {
-                               v3s16 p(x,y,z);
-                               bool is_valid_position;
-                               MapNode n = block->getNode(p, &is_valid_position);
-                               if (!is_valid_position) {
-                                       /* This would happen when dealing with a
-                                          dummy block.
-                                       */
-                                       infostream<<"updateLighting(): InvalidPositionException"
-                                                       <<std::endl;
-                                       continue;
-                               }
-                               u8 oldlight = n.getLight(bank, nodemgr);
-                               n.setLight(bank, 0, nodemgr);
-                               block->setNode(p, n);
-
-                               // If node sources light, add to list
-                               u8 source = nodemgr->get(n).light_source;
-                               if(source != 0)
-                                       light_sources.insert(p + posnodes);
-
-                               // Collect borders for unlighting
-                               if((x==0 || x == MAP_BLOCKSIZE-1
-                                               || y==0 || y == MAP_BLOCKSIZE-1
-                                               || z==0 || z == MAP_BLOCKSIZE-1)
-                                               && oldlight != 0)
-                               {
-                                       v3s16 p_map = p + posnodes;
-                                       unlight_from[p_map] = oldlight;
-                               }
-
-
-                       }
-
-                       if(bank == LIGHTBANK_DAY)
-                       {
-                               bool bottom_valid = block->propagateSunlight(light_sources);
-
-                               if(!bottom_valid)
-                                       num_bottom_invalid++;
-
-                               // If bottom is valid, we're done.
-                               if(bottom_valid)
-                                       break;
-                       }
-                       else if(bank == LIGHTBANK_NIGHT)
-                       {
-                               // For night lighting, sunlight is not propagated
-                               break;
-                       }
-                       else
-                       {
-                               // Invalid lighting bank
-                               assert(0);
-                       }
-
-                       /*infostream<<"Bottom for sunlight-propagated block ("
-                                       <<pos.X<<","<<pos.Y<<","<<pos.Z<<") not valid"
-                                       <<std::endl;*/
-
-                       // Bottom sunlight is not valid; get the block and loop to it
-
-                       pos.Y--;
-                       try{
-                               block = getBlockNoCreate(pos);
-                       }
-                       catch(InvalidPositionException &e)
-                       {
-                               assert(0);
-                       }
-
-               }
-       }
-
-       }
-
-       /*
-               Enable this to disable proper lighting for speeding up map
-               generation for testing or whatever
-       */
-#if 0
-       //if(g_settings->get(""))
-       {
-               core::map<v3s16, MapBlock*>::Iterator i;
-               i = blocks_to_update.getIterator();
-               for(; i.atEnd() == false; i++)
-               {
-                       MapBlock *block = i.getNode()->getValue();
-                       v3s16 p = block->getPos();
-                       block->setLightingExpired(false);
-               }
-               return;
-       }
-#endif
-
-#if 1
-       {
-               //TimeTaker timer("unspreadLight");
-               unspreadLight(bank, unlight_from, light_sources, modified_blocks);
-       }
-
-       /*if(debug)
-       {
-               u32 diff = modified_blocks.size() - count_was;
-               count_was = modified_blocks.size();
-               infostream<<"unspreadLight modified "<<diff<<std::endl;
-       }*/
-
-       {
-               //TimeTaker timer("spreadLight");
-               spreadLight(bank, light_sources, modified_blocks);
-       }
-
-       /*if(debug)
-       {
-               u32 diff = modified_blocks.size() - count_was;
-               count_was = modified_blocks.size();
-               infostream<<"spreadLight modified "<<diff<<std::endl;
-       }*/
-#endif
-
-#if 0
-       {
-               //MapVoxelManipulator vmanip(this);
-
-               // Make a manual voxel manipulator and load all the blocks
-               // that touch the requested blocks
-               ManualMapVoxelManipulator vmanip(this);
-
-               {
-               //TimeTaker timer("initialEmerge");
-
-               core::map<v3s16, MapBlock*>::Iterator i;
-               i = blocks_to_update.getIterator();
-               for(; i.atEnd() == false; i++)
-               {
-                       MapBlock *block = i.getNode()->getValue();
-                       v3s16 p = block->getPos();
-
-                       // Add all surrounding blocks
-                       vmanip.initialEmerge(p - v3s16(1,1,1), p + v3s16(1,1,1));
-
-                       /*
-                               Add all surrounding blocks that have up-to-date lighting
-                               NOTE: This doesn't quite do the job (not everything
-                                         appropriate is lighted)
-                       */
-                       /*for(s16 z=-1; z<=1; z++)
-                       for(s16 y=-1; y<=1; y++)
-                       for(s16 x=-1; x<=1; x++)
-                       {
-                               v3s16 p2 = p + v3s16(x,y,z);
-                               MapBlock *block = getBlockNoCreateNoEx(p2);
-                               if(block == NULL)
-                                       continue;
-                               if(block->isDummy())
-                                       continue;
-                               if(block->getLightingExpired())
-                                       continue;
-                               vmanip.initialEmerge(p2, p2);
-                       }*/
-
-                       // Lighting of block will be updated completely
-                       block->setLightingExpired(false);
-               }
-               }
-
-               {
-                       //TimeTaker timer("unSpreadLight");
-                       vmanip.unspreadLight(bank, unlight_from, light_sources, nodemgr);
-               }
-               {
-                       //TimeTaker timer("spreadLight");
-                       vmanip.spreadLight(bank, light_sources, nodemgr);
-               }
-               {
-                       //TimeTaker timer("blitBack");
-                       vmanip.blitBack(modified_blocks);
-               }
-               /*infostream<<"emerge_time="<<emerge_time<<std::endl;
-               emerge_time = 0;*/
-       }
-#endif
-
-       //m_dout<<"Done ("<<getTimestamp()<<")"<<std::endl;
-}
-
-void Map::updateLighting(std::map<v3s16, MapBlock*> & a_blocks,
-               std::map<v3s16, MapBlock*> & modified_blocks)
-{
-       updateLighting(LIGHTBANK_DAY, a_blocks, modified_blocks);
-       updateLighting(LIGHTBANK_NIGHT, a_blocks, modified_blocks);
-
-       /*
-               Update information about whether day and night light differ
-       */
-       for(std::map<v3s16, MapBlock*>::iterator
-                       i = modified_blocks.begin();
-                       i != modified_blocks.end(); ++i)
-       {
-               MapBlock *block = i->second;
-               block->expireDayNightDiff();
-       }
-}
-
-/*
-*/
 void Map::addNodeAndUpdate(v3s16 p, MapNode n,
                std::map<v3s16, MapBlock*> &modified_blocks,
                bool remove_metadata)
 {
-       INodeDefManager *ndef = m_gamedef->ndef();
-
-       /*PrintInfo(m_dout);
-       m_dout<<DTIME<<"Map::addNodeAndUpdate(): p=("
-                       <<p.X<<","<<p.Y<<","<<p.Z<<")"<<std::endl;*/
-
-       /*
-               From this node to nodes underneath:
-               If lighting is sunlight (1.0), unlight neighbours and
-               set lighting to 0.
-               Else discontinue.
-       */
-
-       v3s16 toppos = p + v3s16(0,1,0);
-       //v3s16 bottompos = p + v3s16(0,-1,0);
-
-       bool node_under_sunlight = true;
-       std::set<v3s16> light_sources;
-
-       /*
-               Collect old node for rollback
-       */
+       // Collect old node for rollback
        RollbackNode rollback_oldnode(this, p, m_gamedef);
 
-       /*
-               If there is a node at top and it doesn't have sunlight,
-               there has not been any sunlight going down.
-
-               Otherwise there probably is.
-       */
+       // This is needed for updating the lighting
+       MapNode oldnode = getNodeNoEx(p);
 
-       bool is_valid_position;
-       MapNode topnode = getNodeNoEx(toppos, &is_valid_position);
-
-       if(is_valid_position && topnode.getLight(LIGHTBANK_DAY, ndef) != LIGHT_SUN)
-               node_under_sunlight = false;
-
-       /*
-               Remove all light that has come out of this node
-       */
-
-       enum LightBank banks[] =
-       {
-               LIGHTBANK_DAY,
-               LIGHTBANK_NIGHT
-       };
-       for(s32 i=0; i<2; i++)
-       {
-               enum LightBank bank = banks[i];
-
-               u8 lightwas = getNodeNoEx(p).getLight(bank, ndef);
-
-               // Add the block of the added node to modified_blocks
-               v3s16 blockpos = getNodeBlockPos(p);
-               MapBlock * block = getBlockNoCreate(blockpos);
-               assert(block != NULL);
-               modified_blocks[blockpos] = block;
-
-               assert(isValidPosition(p));
-
-               // Unlight neighbours of node.
-               // This means setting light of all consequent dimmer nodes
-               // to 0.
-               // This also collects the nodes at the border which will spread
-               // light again into this.
-               unLightNeighbors(bank, p, lightwas, light_sources, modified_blocks);
-
-               n.setLight(bank, 0, ndef);
-       }
-
-       /*
-               If node lets sunlight through and is under sunlight, it has
-               sunlight too.
-       */
-       if(node_under_sunlight && ndef->get(n).sunlight_propagates)
-       {
-               n.setLight(LIGHTBANK_DAY, LIGHT_SUN, ndef);
-       }
-
-       /*
-               Remove node metadata
-       */
+       // Remove node metadata
        if (remove_metadata) {
                removeNodeMetadata(p);
        }
 
-       /*
-               Set the node on the map
-       */
-
-       setNode(p, n);
-
-       /*
-               If node is under sunlight and doesn't let sunlight through,
-               take all sunlighted nodes under it and clear light from them
-               and from where the light has been spread.
-               TODO: This could be optimized by mass-unlighting instead
-                         of looping
-       */
-       if(node_under_sunlight && !ndef->get(n).sunlight_propagates)
-       {
-               s16 y = p.Y - 1;
-               for(;; y--){
-                       //m_dout<<DTIME<<"y="<<y<<std::endl;
-                       v3s16 n2pos(p.X, y, p.Z);
-
-                       MapNode n2;
-
-                       n2 = getNodeNoEx(n2pos, &is_valid_position);
-                       if (!is_valid_position)
-                               break;
-
-                       if(n2.getLight(LIGHTBANK_DAY, ndef) == LIGHT_SUN)
-                       {
-                               unLightNeighbors(LIGHTBANK_DAY,
-                                               n2pos, n2.getLight(LIGHTBANK_DAY, ndef),
-                                               light_sources, modified_blocks);
-                               n2.setLight(LIGHTBANK_DAY, 0, ndef);
-                               setNode(n2pos, n2);
-                       }
-                       else
-                               break;
-               }
-       }
-
-       for(s32 i=0; i<2; i++)
-       {
-               enum LightBank bank = banks[i];
-
-               /*
-                       Spread light from all nodes that might be capable of doing so
-               */
-               spreadLight(bank, light_sources, modified_blocks);
-       }
-
-       /*
-               Update information about whether day and night light differ
-       */
-       for(std::map<v3s16, MapBlock*>::iterator
-                       i = modified_blocks.begin();
-                       i != modified_blocks.end(); ++i)
-       {
-               i->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 the node itself if it is
-               liquid (=water node was added) to transform queue.
-       */
-       v3s16 dirs[7] = {
-               v3s16(0,0,0), // self
-               v3s16(0,0,1), // back
-               v3s16(0,1,0), // top
-               v3s16(1,0,0), // right
-               v3s16(0,0,-1), // front
-               v3s16(0,-1,0), // bottom
-               v3s16(-1,0,0), // left
-       };
-       for(u16 i=0; i<7; i++)
-       {
-               v3s16 p2 = p + dirs[i];
-
-               MapNode n2 = getNodeNoEx(p2, &is_valid_position);
-               if(is_valid_position
-                               && (ndef->get(n2).isLiquid() || n2.getContent() == CONTENT_AIR))
-               {
-                       m_transforming_liquid.push_back(p2);
-               }
-       }
-}
-
-/*
-*/
-void Map::removeNodeAndUpdate(v3s16 p,
-               std::map<v3s16, MapBlock*> &modified_blocks)
-{
-       INodeDefManager *ndef = m_gamedef->ndef();
-
-       /*PrintInfo(m_dout);
-       m_dout<<DTIME<<"Map::removeNodeAndUpdate(): p=("
-                       <<p.X<<","<<p.Y<<","<<p.Z<<")"<<std::endl;*/
-
-       bool node_under_sunlight = true;
-
-       v3s16 toppos = p + v3s16(0,1,0);
-
-       // Node will be replaced with this
-       content_t replace_material = CONTENT_AIR;
-
-       /*
-               Collect old node for rollback
-       */
-       RollbackNode rollback_oldnode(this, p, m_gamedef);
-
-       /*
-               If there is a node at top and it doesn't have sunlight,
-               there will be no sunlight going down.
-       */
-       bool is_valid_position;
-       MapNode topnode = getNodeNoEx(toppos, &is_valid_position);
-
-       if(is_valid_position && topnode.getLight(LIGHTBANK_DAY, ndef) != LIGHT_SUN)
-               node_under_sunlight = false;
-
-       std::set<v3s16> light_sources;
-
-       enum LightBank banks[] =
-       {
-               LIGHTBANK_DAY,
-               LIGHTBANK_NIGHT
-       };
-       for(s32 i=0; i<2; i++)
-       {
-               enum LightBank bank = banks[i];
-
-               /*
-                       Unlight neighbors (in case the node is a light source)
-               */
-               unLightNeighbors(bank, p,
-                               getNodeNoEx(p).getLight(bank, ndef),
-                               light_sources, modified_blocks);
-       }
-
-       /*
-               Remove node metadata
-       */
-
-       removeNodeMetadata(p);
-
-       /*
-               Remove the node.
-               This also clears the lighting.
-       */
-
-       MapNode n;
-       n.setContent(replace_material);
-       setNode(p, n);
-
-       for(s32 i=0; i<2; i++)
-       {
-               enum LightBank bank = banks[i];
-
-               /*
-                       Recalculate lighting
-               */
-               spreadLight(bank, light_sources, modified_blocks);
-       }
-
-       // Add the block of the removed node to modified_blocks
-       v3s16 blockpos = getNodeBlockPos(p);
-       MapBlock * block = getBlockNoCreate(blockpos);
-       assert(block != NULL);
-       modified_blocks[blockpos] = block;
-
-       /*
-               If the removed node was under sunlight, propagate the
-               sunlight down from it and then light all neighbors
-               of the propagated blocks.
-       */
-       if(node_under_sunlight)
-       {
-               s16 ybottom = propagateSunlight(p, modified_blocks);
-               /*m_dout<<DTIME<<"Node was under sunlight. "
-                               "Propagating sunlight";
-               m_dout<<DTIME<<" -> ybottom="<<ybottom<<std::endl;*/
-               s16 y = p.Y;
-               for(; y >= ybottom; y--)
-               {
-                       v3s16 p2(p.X, y, p.Z);
-                       /*m_dout<<DTIME<<"lighting neighbors of node ("
-                                       <<p2.X<<","<<p2.Y<<","<<p2.Z<<")"
-                                       <<std::endl;*/
-                       lightNeighbors(LIGHTBANK_DAY, p2, modified_blocks);
-               }
-       }
-       else
-       {
-               // Set the lighting of this node to 0
-               // TODO: Is this needed? Lighting is cleared up there already.
-               MapNode n = getNodeNoEx(p, &is_valid_position);
-               if (is_valid_position) {
-                       n.setLight(LIGHTBANK_DAY, 0, ndef);
-                       setNode(p, n);
-               } else {
-                       assert(0);
-               }
-       }
-
-       for(s32 i=0; i<2; i++)
-       {
-               enum LightBank bank = banks[i];
-
-               // Get the brightest neighbour node and propagate light from it
-               v3s16 n2p = getBrightestNeighbour(bank, p);
-               try{
-                       //MapNode n2 = getNode(n2p);
-                       lightNeighbors(bank, n2p, modified_blocks);
-               }
-               catch(InvalidPositionException &e)
-               {
-               }
-       }
+       // 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 information about whether day and night light differ
-       */
-       for(std::map<v3s16, MapBlock*>::iterator
-                       i = modified_blocks.begin();
-                       i != modified_blocks.end(); ++i)
-       {
-               i->second->expireDayNightDiff();
+       // 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
-       */
+       // Report for rollback
        if(m_gamedef->rollback())
        {
                RollbackNode rollback_newnode(this, p, m_gamedef);
@@ -1281,31 +266,27 @@ void Map::removeNodeAndUpdate(v3s16 p,
 
        /*
                Add neighboring liquid nodes and this node to transform queue.
-               (it's vital for the node itself to get updated last.)
-       */
-       v3s16 dirs[7] = {
-               v3s16(0,0,1), // back
-               v3s16(0,1,0), // top
-               v3s16(1,0,0), // right
-               v3s16(0,0,-1), // front
-               v3s16(0,-1,0), // bottom
-               v3s16(-1,0,0), // left
-               v3s16(0,0,0), // self
-       };
-       for(u16 i=0; i<7; i++)
-       {
-               v3s16 p2 = p + dirs[i];
+               (it's vital for the node itself to get updated last, if it was removed.)
+        */
 
-               bool is_position_valid;
-               MapNode n2 = getNodeNoEx(p2, &is_position_valid);
-               if (is_position_valid
-                               && (ndef->get(n2).isLiquid() || n2.getContent() == CONTENT_AIR))
-               {
+       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;
@@ -1319,11 +300,8 @@ bool Map::addNodeWithEvent(v3s16 p, MapNode n, bool remove_metadata)
                addNodeAndUpdate(p, n, modified_blocks, remove_metadata);
 
                // Copy modified_blocks to event
-               for(std::map<v3s16, MapBlock*>::iterator
-                               i = modified_blocks.begin();
-                               i != modified_blocks.end(); ++i)
-               {
-                       event.modified_blocks.insert(i->first);
+               for (auto &modified_block : modified_blocks) {
+                       event.modified_blocks.insert(modified_block.first);
                }
        }
        catch(InvalidPositionException &e){
@@ -1347,11 +325,8 @@ bool Map::removeNodeWithEvent(v3s16 p)
                removeNodeAndUpdate(p, modified_blocks);
 
                // Copy modified_blocks to event
-               for(std::map<v3s16, MapBlock*>::iterator
-                               i = modified_blocks.begin();
-                               i != modified_blocks.end(); ++i)
-               {
-                       event.modified_blocks.insert(i->first);
+               for (auto &modified_block : modified_blocks) {
+                       event.modified_blocks.insert(modified_block.first);
                }
        }
        catch(InvalidPositionException &e){
@@ -1363,128 +338,131 @@ bool Map::removeNodeWithEvent(v3s16 p)
        return succeeded;
 }
 
-bool Map::getDayNightDiff(v3s16 blockpos)
-{
-       try{
-               v3s16 p = blockpos + v3s16(0,0,0);
-               MapBlock *b = getBlockNoCreate(p);
-               if(b->getDayNightDiff())
-                       return true;
-       }
-       catch(InvalidPositionException &e){}
-       // Leading edges
-       try{
-               v3s16 p = blockpos + v3s16(-1,0,0);
-               MapBlock *b = getBlockNoCreate(p);
-               if(b->getDayNightDiff())
-                       return true;
-       }
-       catch(InvalidPositionException &e){}
-       try{
-               v3s16 p = blockpos + v3s16(0,-1,0);
-               MapBlock *b = getBlockNoCreate(p);
-               if(b->getDayNightDiff())
-                       return true;
-       }
-       catch(InvalidPositionException &e){}
-       try{
-               v3s16 p = blockpos + v3s16(0,0,-1);
-               MapBlock *b = getBlockNoCreate(p);
-               if(b->getDayNightDiff())
-                       return true;
-       }
-       catch(InvalidPositionException &e){}
-       // Trailing edges
-       try{
-               v3s16 p = blockpos + v3s16(1,0,0);
-               MapBlock *b = getBlockNoCreate(p);
-               if(b->getDayNightDiff())
-                       return true;
-       }
-       catch(InvalidPositionException &e){}
-       try{
-               v3s16 p = blockpos + v3s16(0,1,0);
-               MapBlock *b = getBlockNoCreate(p);
-               if(b->getDayNightDiff())
-                       return true;
-       }
-       catch(InvalidPositionException &e){}
-       try{
-               v3s16 p = blockpos + v3s16(0,0,1);
-               MapBlock *b = getBlockNoCreate(p);
-               if(b->getDayNightDiff())
-                       return true;
-       }
-       catch(InvalidPositionException &e){}
+struct TimeOrderedMapBlock {
+       MapSector *sect;
+       MapBlock *block;
 
-       return false;
-}
+       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,
-               std::list<v3s16> *unloaded_blocks)
+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::list<v2s16> sector_deletion_queue;
+       std::vector<v2s16> sector_deletion_queue;
        u32 deleted_blocks_count = 0;
        u32 saved_blocks_count = 0;
        u32 block_count_all = 0;
 
        beginSave();
-       for(std::map<v2s16, MapSector*>::iterator si = m_sectors.begin();
-               si != m_sectors.end(); ++si)
-       {
-               MapSector *sector = si->second;
 
-               bool all_blocks_deleted = true;
+       // 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;
 
-               std::list<MapBlock*> blocks;
-               sector->getBlocks(blocks);
+                       bool all_blocks_deleted = true;
 
-               for(std::list<MapBlock*>::iterator i = blocks.begin();
-                               i != blocks.end(); ++i)
-               {
-                       MapBlock *block = (*i);
+                       MapBlockVect blocks;
+                       sector->getBlocks(blocks);
 
-                       block->incrementUsageTimer(dtime);
+                       for (MapBlock *block : blocks) {
+                               block->incrementUsageTimer(dtime);
 
-                       if(block->refGet() == 0 && block->getUsageTimer() > unload_timeout)
-                       {
-                               v3s16 p = block->getPos();
+                               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->getModifiedReason(), 1);
-                                       if (!saveBlock(block))
-                                               continue;
-                                       saved_blocks_count++;
-                               }
+                                       // 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);
 
-                               // Delete from memory
-                               sector->deleteBlock(block);
+                                       if (unloaded_blocks)
+                                               unloaded_blocks->push_back(p);
 
-                               if(unloaded_blocks)
-                                       unloaded_blocks->push_back(p);
+                                       deleted_blocks_count++;
+                               } else {
+                                       all_blocks_deleted = false;
+                                       block_count_all++;
+                               }
+                       }
 
-                               deleted_blocks_count++;
+                       if (all_blocks_deleted) {
+                               sector_deletion_queue.push_back(sector_it.first);
                        }
-                       else
-                       {
-                               all_blocks_deleted = false;
-                               block_count_all++;
+               }
+       } 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();
 
-               if(all_blocks_deleted)
-               {
-                       sector_deletion_queue.push_back(si->first);
+                       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();
@@ -1509,83 +487,24 @@ void Map::timerUpdate(float dtime, float unload_timeout,
        }
 }
 
-void Map::unloadUnreferencedBlocks(std::list<v3s16> *unloaded_blocks)
+void Map::unloadUnreferencedBlocks(std::vector<v3s16> *unloaded_blocks)
 {
-       timerUpdate(0.0, -1.0, unloaded_blocks);
+       timerUpdate(0.0, -1.0, 0, unloaded_blocks);
 }
 
-void Map::deleteSectors(std::list<v2s16> &list)
+void Map::deleteSectors(std::vector<v2s16> &sectorList)
 {
-       for(std::list<v2s16>::iterator j = list.begin();
-               j != list.end(); ++j)
-       {
-               MapSector *sector = m_sectors[*j];
+       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);
+               m_sectors.erase(j);
                delete sector;
        }
 }
 
-#if 0
-void Map::unloadUnusedData(float timeout,
-               core::list<v3s16> *deleted_blocks)
-{
-       core::list<v2s16> sector_deletion_queue;
-       u32 deleted_blocks_count = 0;
-       u32 saved_blocks_count = 0;
-
-       core::map<v2s16, MapSector*>::Iterator si = m_sectors.getIterator();
-       for(; si.atEnd() == false; si++)
-       {
-               MapSector *sector = si.getNode()->getValue();
-
-               bool all_blocks_deleted = true;
-
-               core::list<MapBlock*> blocks;
-               sector->getBlocks(blocks);
-               for(core::list<MapBlock*>::Iterator i = blocks.begin();
-                               i != blocks.end(); i++)
-               {
-                       MapBlock *block = (*i);
-
-                       if(block->getUsageTimer() > timeout)
-                       {
-                               // Save if modified
-                               if(block->getModified() != MOD_STATE_CLEAN)
-                               {
-                                       saveBlock(block);
-                                       saved_blocks_count++;
-                               }
-                               // Delete from memory
-                               sector->deleteBlock(block);
-                               deleted_blocks_count++;
-                       }
-                       else
-                       {
-                               all_blocks_deleted = false;
-                       }
-               }
-
-               if(all_blocks_deleted)
-               {
-                       sector_deletion_queue.push_back(si.getNode()->getKey());
-               }
-       }
-
-       deleteSectors(sector_deletion_queue);
-
-       infostream<<"Map: Unloaded "<<deleted_blocks_count<<" blocks from memory"
-                       <<", of which "<<saved_blocks_count<<" were wr."
-                       <<std::endl;
-
-       //return sector_deletion_queue.getSize();
-       //return deleted_blocks_count;
-}
-#endif
-
 void Map::PrintInfo(std::ostream &out)
 {
        out<<"Map: ";
@@ -1593,34 +512,35 @@ void Map::PrintInfo(std::ostream &out)
 
 #define WATER_DROP_BOOST 4
 
-enum NeighborType {
+enum NeighborType : u8 {
        NEIGHBOR_UPPER,
        NEIGHBOR_SAME_LEVEL,
        NEIGHBOR_LOWER
 };
+
 struct NodeNeighbor {
        MapNode n;
        NeighborType t;
        v3s16 p;
-       bool l; //can liquid
+
+       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);
 }
 
-s32 Map::transforming_liquid_size() {
-        return m_transforming_liquid.size();
-}
-
-void Map::transformLiquids(std::map<v3s16, MapBlock*> & modified_blocks)
+void Map::transformLiquids(std::map<v3s16, MapBlock*> &modified_blocks,
+               ServerEnvironment *env)
 {
-
-       INodeDefManager *nodemgr = m_gamedef->ndef();
-
-       DSTACK(__FUNCTION_NAME);
-       //TimeTaker timer("transformLiquids()");
-
        u32 loopcount = 0;
        u32 initial_size = m_transforming_liquid.size();
 
@@ -1628,10 +548,9 @@ void Map::transformLiquids(std::map<v3s16, MapBlock*> & modified_blocks)
                infostream<<"transformLiquids(): initial_size="<<initial_size<<std::endl;*/
 
        // list of nodes that due to viscosity have not reached their max level height
-       UniqueQueue<v3s16> must_reflow;
+       std::deque<v3s16> must_reflow;
 
-       // List of MapBlocks that will require a lighting update (due to lava)
-       std::map<v3s16, MapBlock*> lighting_modified_blocks;
+       std::vector<std::pair<v3s16, MapNode> > changed_nodes;
 
        u32 liquid_loop_max = g_settings->getS32("liquid_loop_max");
        u32 loop_max = liquid_loop_max;
@@ -1653,10 +572,10 @@ void Map::transformLiquids(std::map<v3s16, MapBlock*> & modified_blocks)
        loop_max *= m_transforming_liquid_loop_count_multiplier;
 #endif
 
-       while(m_transforming_liquid.size() != 0)
+       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)
+               if (loopcount >= initial_size || loopcount >= loop_max)
                        break;
                loopcount++;
 
@@ -1672,22 +591,29 @@ void Map::transformLiquids(std::map<v3s16, MapBlock*> & modified_blocks)
                        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;
-               LiquidType liquid_type = nodemgr->get(n0).liquid_type;
+               // 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 = nodemgr->getId(nodemgr->get(n0).liquid_alternative_flowing);
+                               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 is an air node, it *could* be transformed into a liquid. otherwise,
-                               // continue with the next node.
-                               if (n0.getContent() != CONTENT_AIR)
+                               // 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;
                }
@@ -1705,6 +631,7 @@ void Map::transformLiquids(std::map<v3s16, MapBlock*> & modified_blocks)
                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) {
@@ -1714,12 +641,15 @@ void Map::transformLiquids(std::map<v3s16, MapBlock*> & modified_blocks)
                                case 4:
                                        nt = NEIGHBOR_LOWER;
                                        break;
+                               default:
+                                       break;
                        }
                        v3s16 npos = p0 + dirs[i];
-                       NodeNeighbor nb = {getNodeNoEx(npos), nt, npos};
-                       switch (nodemgr->get(nb.n.getContent()).liquid_type) {
+                       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 (nb.n.getContent() == CONTENT_AIR) {
+                                       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
@@ -1727,18 +657,26 @@ void Map::transformLiquids(std::map<v3s16, MapBlock*> & modified_blocks)
                                                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) {
+                                               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 = nodemgr->getId(nodemgr->get(nb.n).liquid_alternative_flowing);
-                                       if (nodemgr->getId(nodemgr->get(nb.n).liquid_alternative_flowing) != liquid_kind) {
+                                               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
@@ -1749,8 +687,8 @@ void Map::transformLiquids(std::map<v3s16, MapBlock*> & modified_blocks)
                                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 = nodemgr->getId(nodemgr->get(nb.n).liquid_alternative_flowing);
-                                       if (nodemgr->getId(nodemgr->get(nb.n).liquid_alternative_flowing) != liquid_kind) {
+                                               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;
@@ -1768,21 +706,27 @@ void Map::transformLiquids(std::map<v3s16, MapBlock*> & modified_blocks)
                s8 new_node_level = -1;
                s8 max_node_level = -1;
 
-               u8 range = nodemgr->get(liquid_kind).liquid_range;
-               if (range > LIQUID_LEVEL_MAX+1)
-                       range = LIQUID_LEVEL_MAX+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 && nodemgr->get(liquid_kind).liquid_renewable) || liquid_type == LIQUID_SOURCE) {
+               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 = nodemgr->getId(nodemgr->get(liquid_kind).liquid_alternative_source);
+                       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
-                       new_node_content = liquid_kind;
                        max_node_level = new_node_level = LIQUID_LEVEL_MAX;
-                       if (new_node_level < (LIQUID_LEVEL_MAX+1-range))
-                               new_node_content = CONTENT_AIR;
+                       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++) {
@@ -1793,21 +737,21 @@ void Map::transformLiquids(std::map<v3s16, MapBlock*> & modified_blocks)
                                                        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)
+                                               } 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) {
+                                                               nb_liquid_level > 0 && nb_liquid_level - 1 > max_node_level)
                                                        max_node_level = nb_liquid_level - 1;
-                                               }
                                                break;
                                }
                        }
 
-                       u8 viscosity = nodemgr->get(liquid_kind).liquid_viscosity;
+                       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
@@ -1820,23 +764,25 @@ void Map::transformLiquids(std::map<v3s16, MapBlock*> & modified_blocks)
                                        new_node_level = liquid_level + 1;
                                if (new_node_level != max_node_level)
                                        must_reflow.push_back(p0);
-                       } else
+                       } else {
                                new_node_level = max_node_level;
+                       }
 
-                       if (max_node_level >= (LIQUID_LEVEL_MAX+1-range))
+                       if (max_node_level >= (LIQUID_LEVEL_MAX + 1 - range))
                                new_node_content = liquid_kind;
                        else
-                               new_node_content = CONTENT_AIR;
+                               new_node_content = floodable_node;
 
                }
 
                /*
                        check if anything has changed. if not, just continue with the next node.
                 */
-               if (new_node_content == n0.getContent() && (nodemgr->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)))
+               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;
 
 
@@ -1845,22 +791,33 @@ void Map::transformLiquids(std::map<v3s16, MapBlock*> & modified_blocks)
                 */
                MapNode n00 = n0;
                //bool flow_down_enabled = (flowing_down && ((n0.param2 & LIQUID_FLOW_DOWN_MASK) != LIQUID_FLOW_DOWN_MASK));
-               if (nodemgr->get(new_node_content).liquid_type == LIQUID_FLOWING) {
+               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()){
+               if (m_gamedef->rollback())
                        suspect = m_gamedef->rollback()->getSuspect(p0, 83, 1);
-               }
 
-               if(!suspect.empty()){
+               if (m_gamedef->rollback() && !suspect.empty()) {
                        // Blame suspect
                        RollbackScopeActor rollback_scope(m_gamedef->rollback(), suspect, true);
                        // Get old node for rollback
@@ -1879,18 +836,15 @@ void Map::transformLiquids(std::map<v3s16, MapBlock*> & modified_blocks)
 
                v3s16 blockpos = getNodeBlockPos(p0);
                MapBlock *block = getBlockNoCreateNoEx(blockpos);
-               if(block != NULL) {
+               if (block != NULL) {
                        modified_blocks[blockpos] =  block;
-                       // If new or old node emits light, MapBlock requires lighting update
-                       if(nodemgr->get(n0).light_source != 0 ||
-                                       nodemgr->get(n00).light_source != 0)
-                               lighting_modified_blocks[block->getPos()] = block;
+                       changed_nodes.emplace_back(p0, n00);
                }
 
                /*
                        enqueue neighbors for update if neccessary
                 */
-               switch (nodemgr->get(n0.getContent()).liquid_type) {
+               switch (m_nodedef->get(n0.getContent()).liquid_type) {
                        case LIQUID_SOURCE:
                        case LIQUID_FLOWING:
                                // make sure source flows into all neighboring nodes
@@ -1909,12 +863,11 @@ void Map::transformLiquids(std::map<v3s16, MapBlock*> & modified_blocks)
                }
        }
        //infostream<<"Map::transformLiquids(): loopcount="<<loopcount<<std::endl;
-       while (must_reflow.size() > 0)
-       {
-               m_transforming_liquid.push_back(must_reflow.front());
-               must_reflow.pop_front();
-       }
-       updateLighting(lighting_modified_blocks, modified_blocks);
+
+       for (auto &iter : must_reflow)
+               m_transforming_liquid.push_back(iter);
+
+       voxalgo::update_lighting_nodes(this, changed_nodes, modified_blocks);
 
 
        /* ----------------------------------------------------------------------
@@ -1927,7 +880,7 @@ void Map::transformLiquids(std::map<v3s16, MapBlock*> & modified_blocks)
 
        time_until_purge *= 1000;       // seconds -> milliseconds
 
-       u32 curr_time = getTime(PRECISION_MILLI);
+       u64 curr_time = porting::getTimeMs();
        u32 prev_unprocessed = m_unprocessed_count;
        m_unprocessed_count = m_transforming_liquid.size();
 
@@ -1966,6 +919,47 @@ void Map::transformLiquids(std::map<v3s16, MapBlock*> & modified_blocks)
        }
 }
 
+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);
@@ -1977,7 +971,7 @@ NodeMetadata *Map::getNodeMetadata(v3s16 p)
                block = emergeBlock(blockpos, false);
        }
        if(!block){
-               infostream<<"WARNING: Map::getNodeMetadata(): Block not found"
+               warningstream<<"Map::getNodeMetadata(): Block not found"
                                <<std::endl;
                return NULL;
        }
@@ -1996,7 +990,7 @@ bool Map::setNodeMetadata(v3s16 p, NodeMetadata *meta)
                block = emergeBlock(blockpos, false);
        }
        if(!block){
-               infostream<<"WARNING: Map::setNodeMetadata(): Block not found"
+               warningstream<<"Map::setNodeMetadata(): Block not found"
                                <<std::endl;
                return false;
        }
@@ -2011,7 +1005,7 @@ void Map::removeNodeMetadata(v3s16 p)
        MapBlock *block = getBlockNoCreateNoEx(blockpos);
        if(block == NULL)
        {
-               infostream<<"WARNING: Map::removeNodeMetadata(): Block not found"
+               warningstream<<"Map::removeNodeMetadata(): Block not found"
                                <<std::endl;
                return;
        }
@@ -2029,16 +1023,18 @@ NodeTimer Map::getNodeTimer(v3s16 p)
                block = emergeBlock(blockpos, false);
        }
        if(!block){
-               infostream<<"WARNING: Map::getNodeTimer(): Block not found"
+               warningstream<<"Map::getNodeTimer(): Block not found"
                                <<std::endl;
                return NodeTimer();
        }
        NodeTimer t = block->m_node_timers.get(p_rel);
-       return t;
+       NodeTimer nt(t.timeout, t.elapsed, p);
+       return nt;
 }
 
-void Map::setNodeTimer(v3s16 p, NodeTimer t)
+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);
@@ -2048,11 +1044,12 @@ void Map::setNodeTimer(v3s16 p, NodeTimer t)
                block = emergeBlock(blockpos, false);
        }
        if(!block){
-               infostream<<"WARNING: Map::setNodeTimer(): Block not found"
+               warningstream<<"Map::setNodeTimer(): Block not found"
                                <<std::endl;
                return;
        }
-       block->m_node_timers.set(p_rel, t);
+       NodeTimer nt(t.timeout, t.elapsed, p_rel);
+       block->m_node_timers.set(nt);
 }
 
 void Map::removeNodeTimer(v3s16 p)
@@ -2062,22 +1059,91 @@ void Map::removeNodeTimer(v3s16 p)
        MapBlock *block = getBlockNoCreateNoEx(blockpos);
        if(block == NULL)
        {
-               infostream<<"WARNING: Map::removeNodeTimer(): Block not found"
+               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(std::string savedir, IGameDef *gamedef, EmergeManager *emerge):
+ServerMap::ServerMap(const std::string &savedir, IGameDef *gamedef,
+               EmergeManager *emerge):
        Map(dout_server, gamedef),
-       m_emerge(emerge),
-       m_map_metadata_changed(true)
+       settings_mgr(g_settings, savedir + DIR_DELIM + "map_meta.txt"),
+       m_emerge(emerge)
 {
-       verbosestream<<__FUNCTION_NAME<<std::endl;
+       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.
@@ -2089,63 +1155,40 @@ ServerMap::ServerMap(std::string savedir, IGameDef *gamedef, EmergeManager *emer
        bool succeeded = conf.readConfigFile(conf_path.c_str());
        if (!succeeded || !conf.exists("backend")) {
                // fall back to sqlite3
-               dbase = new Database_SQLite3(this, savedir);
                conf.set("backend", "sqlite3");
-       } else {
-               std::string backend = conf.get("backend");
-               if (backend == "dummy")
-                       dbase = new Database_Dummy(this);
-               else if (backend == "sqlite3")
-                       dbase = new Database_SQLite3(this, savedir);
-               #if USE_LEVELDB
-               else if (backend == "leveldb")
-                       dbase = new Database_LevelDB(this, savedir);
-               #endif
-               #if USE_REDIS
-               else if (backend == "redis")
-                       dbase = new Database_Redis(this, savedir);
-               #endif
-               else
-                       throw BaseException("Unknown map backend");
        }
+       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
-       {
+       try {
                // If directory exists, check contents and load if possible
-               if(fs::PathExists(m_savedir))
-               {
+               if (fs::PathExists(m_savedir)) {
                        // If directory is empty, it is safe to save into it.
-                       if(fs::GetDirListing(m_savedir).size() == 0)
-                       {
+                       if (fs::GetDirListing(m_savedir).empty()) {
                                infostream<<"ServerMap: Empty save directory is valid."
                                                <<std::endl;
                                m_map_saving_enabled = true;
                        }
                        else
                        {
-                               try{
-                                       // Load map metadata (seed, chunksize)
-                                       loadMapMeta();
-                               }
-                               catch(SettingNotFoundException &e){
-                                       infostream<<"ServerMap:  Some metadata not found."
-                                                         <<" Using default settings."<<std::endl;
-                               }
-                               catch(FileNotGoodException &e){
-                                       infostream<<"WARNING: Could not load map metadata"
-                                                       //<<" Disabling chunk-based generator."
-                                                       <<std::endl;
-                                       //m_chunksize = 0;
-                               }
 
-                               infostream<<"ServerMap: Successfully loaded map "
-                                               <<"metadata from "<<savedir
-                                               <<", assuming valid save directory."
-                                               <<" seed="<< m_emerge->params.seed <<"."
-                                               <<std::endl;
+                               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
@@ -2159,36 +1202,25 @@ ServerMap::ServerMap(std::string savedir, IGameDef *gamedef, EmergeManager *emer
        }
        catch(std::exception &e)
        {
-               infostream<<"WARNING: ServerMap: Failed to load map from "<<savedir
+               warningstream<<"ServerMap: Failed to load map from "<<savedir
                                <<", exception: "<<e.what()<<std::endl;
                infostream<<"Please remove the map or fix it."<<std::endl;
-               infostream<<"WARNING: Map saving will be disabled."<<std::endl;
+               warningstream<<"Map saving will be disabled."<<std::endl;
        }
-
-       infostream<<"Initializing new map."<<std::endl;
-
-       // Create zero sector
-       emergeSector(v2s16(0,0));
-
-       // Initially write whole map
-       save(MOD_STATE_CLEAN);
 }
 
 ServerMap::~ServerMap()
 {
-       verbosestream<<__FUNCTION_NAME<<std::endl;
+       verbosestream<<FUNCTION_NAME<<std::endl;
 
        try
        {
-               if(m_map_saving_enabled)
-               {
+               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;
+                       infostream << "ServerMap: Saved map to " << m_savedir << std::endl;
+               } else {
+                       infostream << "ServerMap: Map not saved" << std::endl;
                }
        }
        catch(std::exception &e)
@@ -2201,6 +1233,8 @@ ServerMap::~ServerMap()
                Close database if it was opened
        */
        delete dbase;
+       if (dbase_ro)
+               delete dbase_ro;
 
 #if 0
        /*
@@ -2215,85 +1249,81 @@ ServerMap::~ServerMap()
 #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 m_emerge->params.seed;
+       return getMapgenParams()->seed;
 }
 
 s16 ServerMap::getWaterLevel()
 {
-       return m_emerge->params.water_level;
+       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(BlockMakeData *data, v3s16 blockpos)
+bool ServerMap::initBlockMake(v3s16 blockpos, BlockMakeData *data)
 {
-       bool enable_mapgen_debug_info = m_emerge->mapgen_debug_info;
-       EMERGE_DBG_OUT("initBlockMake(): " PP(blockpos) " - " PP(blockpos));
+       s16 csize = getMapgenParams()->chunksize;
+       v3s16 bpmin = EmergeManager::getContainingChunk(blockpos, csize);
+       v3s16 bpmax = bpmin + v3s16(1, 1, 1) * (csize - 1);
 
-       s16 chunksize = m_emerge->params.chunksize;
-       s16 coffset = -chunksize / 2;
-       v3s16 chunk_offset(coffset, coffset, coffset);
-       v3s16 blockpos_div = getContainerPos(blockpos - chunk_offset, chunksize);
-       v3s16 blockpos_min = blockpos_div * chunksize;
-       v3s16 blockpos_max = blockpos_div * chunksize + v3s16(1,1,1)*(chunksize-1);
-       blockpos_min += chunk_offset;
-       blockpos_max += chunk_offset;
+       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 extra_borders(1, 1, 1);
+       v3s16 full_bpmin = bpmin - extra_borders;
+       v3s16 full_bpmax = bpmax + extra_borders;
 
-       // Do nothing if not inside limits (+-1 because of neighbors)
-       if(blockpos_over_limit(blockpos_min - extra_borders) ||
-               blockpos_over_limit(blockpos_max + 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 = m_emerge->params.seed;
-       data->blockpos_min = blockpos_min;
-       data->blockpos_max = blockpos_max;
+       data->seed = getSeed();
+       data->blockpos_min = bpmin;
+       data->blockpos_max = bpmax;
        data->blockpos_requested = blockpos;
-       data->nodedef = m_gamedef->ndef();
+       data->nodedef = m_nodedef;
 
        /*
                Create the whole area of this and the neighboring blocks
        */
-       {
-               //TimeTaker timer("initBlockMake() create area");
-
-               for(s16 x=blockpos_min.X-extra_borders.X;
-                               x<=blockpos_max.X+extra_borders.X; x++)
-               for(s16 z=blockpos_min.Z-extra_borders.Z;
-                               z<=blockpos_max.Z+extra_borders.Z; z++)
-               {
-                       v2s16 sectorpos(x, z);
-                       // Sector metadata is loaded from disk if not already loaded.
-                       ServerMapSector *sector = createSector(sectorpos);
-                       assert(sector);
-                       (void) sector;
-
-                       for(s16 y=blockpos_min.Y-extra_borders.Y;
-                                       y<=blockpos_max.Y+extra_borders.Y; y++)
-                       {
-                               v3s16 p(x,y,z);
-                               //MapBlock *block = createBlock(p);
-                               // 1) get from memory, 2) load from disk
-                               MapBlock *block = emergeBlock(p, false);
-                               // 3) create a blank one
-                               if(block == NULL)
-                               {
-                                       block = createBlock(p);
-
-                                       /*
-                                               Block gets sunlight if this is true.
+       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);
 
-                                               Refer to the map generator heuristics.
-                                       */
-                                       bool ug = m_emerge->isBlockUnderground(p);
-                                       block->setIsUnderground(ug);
-                               }
+                       MapBlock *block = emergeBlock(p, false);
+                       if (block == NULL) {
+                               block = createBlock(p);
 
-                               // Lighting will not be valid after make_chunk is called
-                               block->setLightingExpired(true);
-                               // Lighting will be calculated
-                               //block->setLightingExpired(false);
+                               // Block gets sunlight if this is true.
+                               // Refer to the map generator heuristics.
+                               bool ug = m_emerge->isBlockUnderground(p);
+                               block->setIsUnderground(ug);
                        }
                }
        }
@@ -2305,21 +1335,14 @@ bool ServerMap::initBlockMake(BlockMakeData *data, v3s16 blockpos)
                neighboring blocks
        */
 
-       // The area that contains this block and it's neighbors
-       v3s16 bigarea_blocks_min = blockpos_min - extra_borders;
-       v3s16 bigarea_blocks_max = blockpos_max + extra_borders;
-
        data->vmanip = new MMVManip(this);
-       //data->vmanip->setMap(this);
-
-       // Add the area
-       {
-               //TimeTaker timer("initBlockMake() initialEmerge");
-               data->vmanip->initialEmerge(bigarea_blocks_min, bigarea_blocks_max);
-       }
+       data->vmanip->initialEmerge(full_bpmin, full_bpmax);
 
-       // 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++) {
+       // 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;
@@ -2331,124 +1354,43 @@ bool ServerMap::initBlockMake(BlockMakeData *data, v3s16 blockpos)
                                n->setValue(flags);
                        }
                }
-       }*/
+       }
+#endif
 
        // Data is ready now.
        return true;
 }
 
 void ServerMap::finishBlockMake(BlockMakeData *data,
-               std::map<v3s16, MapBlock*> &changed_blocks)
+       std::map<v3s16, MapBlock*> *changed_blocks)
 {
-       v3s16 blockpos_min = data->blockpos_min;
-       v3s16 blockpos_max = data->blockpos_max;
-       v3s16 blockpos_requested = data->blockpos_requested;
-       /*infostream<<"finishBlockMake(): ("<<blockpos_requested.X<<","
-                       <<blockpos_requested.Y<<","
-                       <<blockpos_requested.Z<<")"<<std::endl;*/
+       v3s16 bpmin = data->blockpos_min;
+       v3s16 bpmax = data->blockpos_max;
 
-       v3s16 extra_borders(1,1,1);
+       v3s16 extra_borders(1, 1, 1);
 
-       bool enable_mapgen_debug_info = m_emerge->mapgen_debug_info;
-
-       /*infostream<<"Resulting vmanip:"<<std::endl;
-       data->vmanip.print(infostream);*/
-
-       // Make sure affected blocks are loaded
-       for(s16 x=blockpos_min.X-extra_borders.X;
-                       x<=blockpos_max.X+extra_borders.X; x++)
-       for(s16 z=blockpos_min.Z-extra_borders.Z;
-                       z<=blockpos_max.Z+extra_borders.Z; z++)
-       for(s16 y=blockpos_min.Y-extra_borders.Y;
-                       y<=blockpos_max.Y+extra_borders.Y; y++)
-       {
-               v3s16 p(x, y, z);
-               // Load from disk if not already in memory
-               emergeBlock(p, false);
-       }
+       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
        */
-       {
-               // 70ms @cs=8
-               //TimeTaker timer("finishBlockMake() blitBackAll");
-               data->vmanip->blitBackAll(&changed_blocks);
-       }
+       data->vmanip->blitBackAll(changed_blocks);
 
-       EMERGE_DBG_OUT("finishBlockMake: changed_blocks.size()=" << changed_blocks.size());
+       EMERGE_DBG_OUT("finishBlockMake: changed_blocks.size()="
+               << changed_blocks->size());
 
        /*
                Copy transforming liquid information
        */
-       while(data->transforming_liquid.size() > 0)
-       {
+       while (data->transforming_liquid.size()) {
                m_transforming_liquid.push_back(data->transforming_liquid.front());
                data->transforming_liquid.pop_front();
        }
 
-       /*
-               Do stuff in central blocks
-       */
-
-       /*
-               Update lighting
-       */
-       {
-#if 0
-               TimeTaker t("finishBlockMake lighting update");
-
-               core::map<v3s16, MapBlock*> lighting_update_blocks;
-
-               // Center blocks
-               for(s16 x=blockpos_min.X-extra_borders.X;
-                               x<=blockpos_max.X+extra_borders.X; x++)
-               for(s16 z=blockpos_min.Z-extra_borders.Z;
-                               z<=blockpos_max.Z+extra_borders.Z; z++)
-               for(s16 y=blockpos_min.Y-extra_borders.Y;
-                               y<=blockpos_max.Y+extra_borders.Y; y++)
-               {
-                       v3s16 p(x, y, z);
-                       MapBlock *block = getBlockNoCreateNoEx(p);
-                       assert(block);
-                       lighting_update_blocks.insert(block->getPos(), block);
-               }
-
-               updateLighting(lighting_update_blocks, changed_blocks);
-#endif
-
-               /*
-                       Set lighting to non-expired state in all of them.
-                       This is cheating, but it is not fast enough if all of them
-                       would actually be updated.
-               */
-               for(s16 x=blockpos_min.X-extra_borders.X;
-                               x<=blockpos_max.X+extra_borders.X; x++)
-               for(s16 z=blockpos_min.Z-extra_borders.Z;
-                               z<=blockpos_max.Z+extra_borders.Z; z++)
-               for(s16 y=blockpos_min.Y-extra_borders.Y;
-                               y<=blockpos_max.Y+extra_borders.Y; y++)
-               {
-                       v3s16 p(x, y, z);
-                       MapBlock * block = getBlockNoCreateNoEx(p);
-                       if (block != NULL)
-                               block->setLightingExpired(false);
-               }
-
-#if 0
-               if(enable_mapgen_debug_info == false)
-                       t.stop(true); // Hide output
-#endif
-       }
-
-       /*
-               Go through changed blocks
-       */
-       for(std::map<v3s16, MapBlock*>::iterator i = changed_blocks.begin();
-                       i != changed_blocks.end(); ++i)
-       {
-               MapBlock *block = i->second;
+       for (auto &changed_block : *changed_blocks) {
+               MapBlock *block = changed_block.second;
                if (!block)
                        continue;
                /*
@@ -2459,107 +1401,53 @@ void ServerMap::finishBlockMake(BlockMakeData *data,
                        Set block as modified
                */
                block->raiseModified(MOD_STATE_WRITE_NEEDED,
-                               "finishBlockMake expireDayNightDiff");
+                       MOD_REASON_EXPIRE_DAYNIGHTDIFF);
        }
 
        /*
                Set central blocks as generated
        */
-       for(s16 x=blockpos_min.X; x<=blockpos_max.X; x++)
-       for(s16 z=blockpos_min.Z; z<=blockpos_max.Z; z++)
-       for(s16 y=blockpos_min.Y; y<=blockpos_max.Y; y++)
-       {
-               v3s16 p(x, y, z);
-               MapBlock *block = getBlockNoCreateNoEx(p);
+       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);
-
-       /*infostream<<"finishBlockMake() done for ("<<blockpos_requested.X
-                       <<","<<blockpos_requested.Y<<","
-                       <<blockpos_requested.Z<<")"<<std::endl;*/
-
-
-#if 0
-       if(enable_mapgen_debug_info)
-       {
-               /*
-                       Analyze resulting blocks
-               */
-               /*for(s16 x=blockpos_min.X-1; x<=blockpos_max.X+1; x++)
-               for(s16 z=blockpos_min.Z-1; z<=blockpos_max.Z+1; z++)
-               for(s16 y=blockpos_min.Y-1; y<=blockpos_max.Y+1; y++)*/
-               for(s16 x=blockpos_min.X-0; x<=blockpos_max.X+0; x++)
-               for(s16 z=blockpos_min.Z-0; z<=blockpos_max.Z+0; z++)
-               for(s16 y=blockpos_min.Y-0; y<=blockpos_max.Y+0; y++)
-               {
-                       v3s16 p = v3s16(x,y,z);
-                       MapBlock *block = getBlockNoCreateNoEx(p);
-                       char spos[20];
-                       snprintf(spos, 20, "(%2d,%2d,%2d)", x, y, z);
-                       infostream<<"Generated "<<spos<<": "
-                                       <<analyze_block(block)<<std::endl;
-               }
-       }
-#endif
-
-       getBlockNoCreateNoEx(blockpos_requested);
+               Save changed parts of map
+               NOTE: Will be saved later.
+       */
+       //save(MOD_STATE_WRITE_AT_UNLOAD);
 }
 
-ServerMapSector * ServerMap::createSector(v2s16 p2d)
+MapSector *ServerMap::createSector(v2s16 p2d)
 {
-       DSTACKF("%s: p2d=(%d,%d)",
-                       __FUNCTION_NAME,
-                       p2d.X, p2d.Y);
-
        /*
                Check if it exists already in memory
        */
-       ServerMapSector *sector = (ServerMapSector*)getSectorNoGenerateNoEx(p2d);
-       if(sector != NULL)
+       MapSector *sector = getSectorNoGenerateNoEx(p2d);
+       if (sector)
                return sector;
 
        /*
-               Try to load it from disk (with blocks)
-       */
-       //if(loadSectorFull(p2d) == true)
-
-       /*
-               Try to load metadata from disk
-       */
-#if 0
-       if(loadSectorMeta(p2d) == true)
-       {
-               ServerMapSector *sector = (ServerMapSector*)getSectorNoGenerateNoEx(p2d);
-               if(sector == NULL)
-               {
-                       infostream<<"ServerMap::createSector(): loadSectorFull didn't make a sector"<<std::endl;
-                       throw InvalidPositionException("");
-               }
-               return sector;
-       }
-#endif
-       /*
-               Do not create over-limit
+               Do not create over max mapgen limit
        */
-       if(p2d.X < -MAP_GENERATION_LIMIT / MAP_BLOCKSIZE
-       || p2d.X > MAP_GENERATION_LIMIT / MAP_BLOCKSIZE
-       || p2d.Y < -MAP_GENERATION_LIMIT / MAP_BLOCKSIZE
-       || p2d.Y > MAP_GENERATION_LIMIT / MAP_BLOCKSIZE)
-               throw InvalidPositionException("createSector(): pos. over 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 ServerMapSector(this, p2d, m_gamedef);
+       sector = new MapSector(this, p2d, m_gamedef);
 
        // Sector position on map in nodes
        //v2s16 nodepos2d = p2d * MAP_BLOCKSIZE;
@@ -2581,12 +1469,6 @@ MapBlock * ServerMap::generateBlock(
                std::map<v3s16, MapBlock*> &modified_blocks
 )
 {
-       DSTACKF("%s: p=(%d,%d,%d)", __FUNCTION_NAME, p.X, p.Y, p.Z);
-
-       /*infostream<<"generateBlock(): "
-                       <<"("<<p.X<<","<<p.Y<<","<<p.Z<<")"
-                       <<std::endl;*/
-
        bool enable_mapgen_debug_info = g_settings->getBool("enable_mapgen_debug_info");
 
        TimeTaker timer("generateBlock");
@@ -2601,7 +1483,7 @@ MapBlock * ServerMap::generateBlock(
        */
        if(blockpos_over_limit(p))
        {
-               infostream<<__FUNCTION_NAME<<": Block position over limit"<<std::endl;
+               infostream<<FUNCTION_NAME<<": Block position over limit"<<std::endl;
                throw InvalidPositionException("generateBlock(): pos. over limit");
        }
 
@@ -2690,19 +1572,11 @@ MapBlock * ServerMap::generateBlock(
 
 MapBlock * ServerMap::createBlock(v3s16 p)
 {
-       DSTACKF("%s: p=(%d,%d,%d)",
-                       __FUNCTION_NAME, p.X, p.Y, p.Z);
-
        /*
-               Do not create over-limit
+               Do not create over max mapgen limit
        */
-       if(p.X < -MAP_GENERATION_LIMIT / MAP_BLOCKSIZE
-       || p.X > MAP_GENERATION_LIMIT / MAP_BLOCKSIZE
-       || p.Y < -MAP_GENERATION_LIMIT / MAP_BLOCKSIZE
-       || p.Y > MAP_GENERATION_LIMIT / MAP_BLOCKSIZE
-       || p.Z < -MAP_GENERATION_LIMIT / MAP_BLOCKSIZE
-       || p.Z > MAP_GENERATION_LIMIT / MAP_BLOCKSIZE)
-               throw InvalidPositionException("createBlock(): pos. over 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;
@@ -2713,35 +1587,20 @@ MapBlock * ServerMap::createBlock(v3s16 p)
                NOTE: On old save formats, this will be slow, as it generates
                      lighting on blocks for them.
        */
-       ServerMapSector *sector;
-       try{
-               sector = (ServerMapSector*)createSector(p2d);
-               assert(sector->getId() == MAPSECTOR_SERVER);
-       }
-       catch(InvalidPositionException &e)
-       {
+       MapSector *sector;
+       try {
+               sector = createSector(p2d);
+       } catch (InvalidPositionException &e) {
                infostream<<"createBlock: createSector() failed"<<std::endl;
                throw e;
        }
-       /*
-               NOTE: This should not be done, or at least the exception
-               should not be passed on as std::exception, because it
-               won't be catched at all.
-       */
-       /*catch(std::exception &e)
-       {
-               infostream<<"createBlock: createSector() failed: "
-                               <<e.what()<<std::endl;
-               throw e;
-       }*/
 
        /*
                Try to get a block from the sector
        */
 
        MapBlock *block = sector->getBlockNoCreateNoEx(block_y);
-       if(block)
-       {
+       if (block) {
                if(block->isDummy())
                        block->unDummify();
                return block;
@@ -2754,13 +1613,9 @@ MapBlock * ServerMap::createBlock(v3s16 p)
 
 MapBlock * ServerMap::emergeBlock(v3s16 p, bool create_blank)
 {
-       DSTACKF("%s: p=(%d,%d,%d), create_blank=%d",
-                       __FUNCTION_NAME,
-                       p.X, p.Y, p.Z, create_blank);
-
        {
                MapBlock *block = getBlockNoCreateNoEx(p);
-               if(block && block->isDummy() == false)
+               if (block && !block->isDummy())
                        return block;
        }
 
@@ -2771,39 +1626,12 @@ MapBlock * ServerMap::emergeBlock(v3s16 p, bool create_blank)
        }
 
        if (create_blank) {
-               ServerMapSector *sector = createSector(v2s16(p.X, p.Z));
+               MapSector *sector = createSector(v2s16(p.X, p.Z));
                MapBlock *block = sector->createBlankBlock(p.Y);
 
                return block;
        }
 
-#if 0
-       if(allow_generate)
-       {
-               std::map<v3s16, MapBlock*> modified_blocks;
-               MapBlock *block = generateBlock(p, modified_blocks);
-               if(block)
-               {
-                       MapEditEvent event;
-                       event.type = MEET_OTHER;
-                       event.p = p;
-
-                       // Copy modified_blocks to event
-                       for(std::map<v3s16, MapBlock*>::iterator
-                                       i = modified_blocks.begin();
-                                       i != modified_blocks.end(); ++i)
-                       {
-                               event.modified_blocks.insert(i->first);
-                       }
-
-                       // Queue event
-                       dispatchEvent(&event);
-
-                       return block;
-               }
-       }
-#endif
-
        return NULL;
 }
 
@@ -2816,9 +1644,6 @@ MapBlock *ServerMap::getBlockOrEmerge(v3s16 p3d)
        return block;
 }
 
-void ServerMap::prepareBlock(MapBlock *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)
@@ -2886,16 +1711,16 @@ s16 ServerMap::findGroundLevel(v2s16 p2d)
 }
 
 bool ServerMap::loadFromFolders() {
-       if(!dbase->Initialized() && !fs::PathExists(m_savedir + DIR_DELIM + "map.sqlite")) // ?
+       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) == false)
-       {
-               m_dout<<DTIME<<"ServerMap: Failed to create directory "
+       if (!fs::CreateAllDirs(path)) {
+               m_dout<<"ServerMap: Failed to create directory "
                                <<"\""<<path<<"\""<<std::endl;
                throw BaseException("ServerMap failed to create directory");
        }
@@ -2907,15 +1732,15 @@ std::string ServerMap::getSectorDir(v2s16 pos, int layout)
        switch(layout)
        {
                case 1:
-                       snprintf(cc, 9, "%.4x%.4x",
-                               (unsigned int)pos.X&0xffff,
-                               (unsigned int)pos.Y&0xffff);
+                       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:
-                       snprintf(cc, 9, "%.3x" DIR_DELIM "%.3x",
-                               (unsigned int)pos.X&0xfff,
-                               (unsigned int)pos.Y&0xfff);
+                       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:
@@ -2924,7 +1749,7 @@ std::string ServerMap::getSectorDir(v2s16 pos, int layout)
        }
 }
 
-v2s16 ServerMap::getSectorPos(std::string dirname)
+v2s16 ServerMap::getSectorPos(const std::string &dirname)
 {
        unsigned int x = 0, y = 0;
        int r;
@@ -2939,21 +1764,22 @@ v2s16 ServerMap::getSectorPos(std::string dirname)
        {
                // New layout
                fs::RemoveLastPathComponent(dirname, &component, 2);
-               r = sscanf(component.c_str(), "%3x" DIR_DELIM "%3x", &x, &y);
+               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;
+               if(x & 0x800) x |= 0xF000;
+               if(y & 0x800) y |= 0xF000;
        }
        else
        {
-               assert(false);
+               r = -1;
        }
-       assert(r == 2);
+
+       FATAL_ERROR_IF(r != 2, "getSectorPos()");
        v2s16 pos((s16)x, (s16)y);
        return pos;
 }
 
-v3s16 ServerMap::getBlockPos(std::string sectordir, std::string blockfile)
+v3s16 ServerMap::getBlockPos(const std::string &sectordir, const std::string &blockfile)
 {
        v2s16 p2d = getSectorPos(sectordir);
 
@@ -2970,16 +1796,14 @@ v3s16 ServerMap::getBlockPos(std::string sectordir, std::string blockfile)
 std::string ServerMap::getBlockFilename(v3s16 p)
 {
        char cc[5];
-       snprintf(cc, 5, "%.4x", (unsigned int)p.Y&0xffff);
+       porting::mt_snprintf(cc, sizeof(cc), "%.4x", (unsigned int)p.Y&0xffff);
        return cc;
 }
 
 void ServerMap::save(ModifiedState save_level)
 {
-       DSTACK(__FUNCTION_NAME);
-       if(m_map_saving_enabled == false)
-       {
-               infostream<<"WARNING: Not saving map, saving disabled."<<std::endl;
+       if (!m_map_saving_enabled) {
+               warningstream<<"Not saving map, saving disabled."<<std::endl;
                return;
        }
 
@@ -2987,74 +1811,53 @@ void ServerMap::save(ModifiedState save_level)
                infostream<<"ServerMap: Saving whole map, this can take time."
                                <<std::endl;
 
-       if(m_map_metadata_changed || save_level == MOD_STATE_CLEAN)
-       {
-               saveMapMeta();
+       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 sector_meta_count = 0;
        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(std::map<v2s16, MapSector*>::iterator i = m_sectors.begin();
-               i != m_sectors.end(); ++i)
-       {
-               ServerMapSector *sector = (ServerMapSector*)i->second;
-               assert(sector->getId() == MAPSECTOR_SERVER);
+       for (auto &sector_it : m_sectors) {
+               MapSector *sector = sector_it.second;
 
-               if(sector->differs_from_disk || save_level == MOD_STATE_CLEAN)
-               {
-                       saveSectorMeta(sector);
-                       sector_meta_count++;
-               }
-               std::list<MapBlock*> blocks;
+               MapBlockVect blocks;
                sector->getBlocks(blocks);
 
-               for(std::list<MapBlock*>::iterator j = blocks.begin();
-                       j != blocks.end(); ++j)
-               {
-                       MapBlock *block = *j;
-
+               for (MapBlock *block : blocks) {
                        block_count_all++;
 
-                       if(block->getModified() >= (u32)save_level)
-                       {
+                       if(block->getModified() >= (u32)save_level) {
                                // Lazy beginSave()
-                               if(!save_started){
+                               if(!save_started) {
                                        beginSave();
                                        save_started = true;
                                }
 
-                               modprofiler.add(block->getModifiedReason(), 1);
+                               modprofiler.add(block->getModifiedReasonString(), 1);
 
                                saveBlock(block);
                                block_count++;
-
-                               /*infostream<<"ServerMap: Written block ("
-                                               <<block->getPos().X<<","
-                                               <<block->getPos().Y<<","
-                                               <<block->getPos().Z<<")"
-                                               <<std::endl;*/
                        }
                }
        }
+
        if(save_started)
                endSave();
 
        /*
                Only print if something happened or saved whole map
        */
-       if(save_level == MOD_STATE_CLEAN || sector_meta_count != 0
-                       || block_count != 0)
-       {
+       if(save_level == MOD_STATE_CLEAN
+                       || block_count != 0) {
                infostream<<"ServerMap: Written: "
-                               <<sector_meta_count<<" sector metadata files, "
                                <<block_count<<" block files"
                                <<", "<<block_count_all<<" blocks in memory."
                                <<std::endl;
@@ -3064,266 +1867,59 @@ void ServerMap::save(ModifiedState save_level)
        }
 }
 
-void ServerMap::listAllLoadableBlocks(std::list<v3s16> &dst)
+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;
+       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::list<v3s16> &dst)
+void ServerMap::listAllLoadedBlocks(std::vector<v3s16> &dst)
 {
-       for(std::map<v2s16, MapSector*>::iterator si = m_sectors.begin();
-               si != m_sectors.end(); ++si)
-       {
-               MapSector *sector = si->second;
+       for (auto &sector_it : m_sectors) {
+               MapSector *sector = sector_it.second;
 
-               std::list<MapBlock*> blocks;
+               MapBlockVect blocks;
                sector->getBlocks(blocks);
 
-               for(std::list<MapBlock*>::iterator i = blocks.begin();
-                               i != blocks.end(); ++i)
-               {
-                       MapBlock *block = (*i);
+               for (MapBlock *block : blocks) {
                        v3s16 p = block->getPos();
                        dst.push_back(p);
                }
        }
 }
 
-void ServerMap::saveMapMeta()
-{
-       DSTACK(__FUNCTION_NAME);
-
-       /*infostream<<"ServerMap::saveMapMeta(): "
-                       <<"seed="<<m_seed
-                       <<std::endl;*/
-
-       createDirs(m_savedir);
-
-       std::string fullpath = m_savedir + DIR_DELIM + "map_meta.txt";
-       std::ostringstream ss(std::ios_base::binary);
-
-       Settings params;
-
-       m_emerge->saveParamsToSettings(&params);
-       params.writeLines(ss);
-
-       ss<<"[end_of_params]\n";
-
-       if(!fs::safeWriteToFile(fullpath, ss.str()))
-       {
-               infostream<<"ERROR: ServerMap::saveMapMeta(): "
-                               <<"could not write "<<fullpath<<std::endl;
-               throw FileNotGoodException("Cannot save chunk metadata");
-       }
-
-       m_map_metadata_changed = false;
-}
-
-void ServerMap::loadMapMeta()
-{
-       DSTACK(__FUNCTION_NAME);
-
-       std::string fullpath = m_savedir + DIR_DELIM "map_meta.txt";
-       std::ifstream is(fullpath.c_str(), std::ios_base::binary);
-       if (!is.good()) {
-               errorstream << "ServerMap::loadMapMeta(): "
-                               << "could not open" << fullpath << std::endl;
-               throw FileNotGoodException("Cannot open map metadata");
-       }
-
-       Settings params;
-
-       if (!params.parseConfigLines(is, "[end_of_params]")) {
-               throw SerializationError("ServerMap::loadMapMeta(): "
-                               "[end_of_params] not found!");
-       }
-
-       m_emerge->loadParamsFromSettings(&params);
-
-       verbosestream << "ServerMap::loadMapMeta(): seed="
-               << m_emerge->params.seed << std::endl;
-}
-
-void ServerMap::saveSectorMeta(ServerMapSector *sector)
-{
-       DSTACK(__FUNCTION_NAME);
-       // Format used for writing
-       u8 version = SER_FMT_VER_HIGHEST_WRITE;
-       // Get destination
-       v2s16 pos = sector->getPos();
-       std::string dir = getSectorDir(pos);
-       createDirs(dir);
-
-       std::string fullpath = dir + DIR_DELIM + "meta";
-       std::ostringstream ss(std::ios_base::binary);
-
-       sector->serialize(ss, version);
-
-       if(!fs::safeWriteToFile(fullpath, ss.str()))
-               throw FileNotGoodException("Cannot write sector metafile");
-
-       sector->differs_from_disk = false;
-}
-
-MapSector* ServerMap::loadSectorMeta(std::string sectordir, bool save_after_load)
-{
-       DSTACK(__FUNCTION_NAME);
-       // Get destination
-       v2s16 p2d = getSectorPos(sectordir);
-
-       ServerMapSector *sector = NULL;
-
-       std::string fullpath = sectordir + DIR_DELIM + "meta";
-       std::ifstream is(fullpath.c_str(), std::ios_base::binary);
-       if(is.good() == false)
-       {
-               // If the directory exists anyway, it probably is in some old
-               // format. Just go ahead and create the sector.
-               if(fs::PathExists(sectordir))
-               {
-                       /*infostream<<"ServerMap::loadSectorMeta(): Sector metafile "
-                                       <<fullpath<<" doesn't exist but directory does."
-                                       <<" Continuing with a sector with no metadata."
-                                       <<std::endl;*/
-                       sector = new ServerMapSector(this, p2d, m_gamedef);
-                       m_sectors[p2d] = sector;
-               }
-               else
-               {
-                       throw FileNotGoodException("Cannot open sector metafile");
-               }
-       }
-       else
-       {
-               sector = ServerMapSector::deSerialize
-                               (is, this, p2d, m_sectors, m_gamedef);
-               if(save_after_load)
-                       saveSectorMeta(sector);
-       }
-
-       sector->differs_from_disk = false;
-
-       return sector;
-}
-
-bool ServerMap::loadSectorMeta(v2s16 p2d)
-{
-       DSTACK(__FUNCTION_NAME);
-
-       MapSector *sector = NULL;
-
-       // 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.
-       int loadlayout = 1;
-       std::string sectordir1 = getSectorDir(p2d, 1);
-       std::string sectordir;
-       if(fs::PathExists(sectordir1))
-       {
-               sectordir = sectordir1;
-       }
-       else
-       {
-               loadlayout = 2;
-               sectordir = getSectorDir(p2d, 2);
-       }
-
-       try{
-               sector = loadSectorMeta(sectordir, loadlayout != 2);
-       }
-       catch(InvalidFilenameException &e)
-       {
-               return false;
-       }
-       catch(FileNotGoodException &e)
-       {
-               return false;
-       }
-       catch(std::exception &e)
-       {
-               return false;
-       }
-
-       return true;
-}
-
-#if 0
-bool ServerMap::loadSectorFull(v2s16 p2d)
+MapDatabase *ServerMap::createDatabase(
+       const std::string &name,
+       const std::string &savedir,
+       Settings &conf)
 {
-       DSTACK(__FUNCTION_NAME);
-
-       MapSector *sector = NULL;
-
-       // 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.
-       int loadlayout = 1;
-       std::string sectordir1 = getSectorDir(p2d, 1);
-       std::string sectordir;
-       if(fs::PathExists(sectordir1))
-       {
-               sectordir = sectordir1;
-       }
-       else
-       {
-               loadlayout = 2;
-               sectordir = getSectorDir(p2d, 2);
-       }
-
-       try{
-               sector = loadSectorMeta(sectordir, loadlayout != 2);
-       }
-       catch(InvalidFilenameException &e)
-       {
-               return false;
-       }
-       catch(FileNotGoodException &e)
-       {
-               return false;
-       }
-       catch(std::exception &e)
-       {
-               return false;
-       }
-
-       /*
-               Load blocks
-       */
-       std::vector<fs::DirListNode> list2 = fs::GetDirListing
-                       (sectordir);
-       std::vector<fs::DirListNode>::iterator i2;
-       for(i2=list2.begin(); i2!=list2.end(); i2++)
-       {
-               // We want files
-               if(i2->dir)
-                       continue;
-               try{
-                       loadBlock(sectordir, i2->name, sector, loadlayout != 2);
-               }
-               catch(InvalidFilenameException &e)
-               {
-                       // This catches unknown crap in directory
-               }
-       }
-
-       if(loadlayout != 2)
-       {
-               infostream<<"Sector converted to new layout - deleting "<<
-                       sectordir1<<std::endl;
-               fs::RecursiveDelete(sectordir1);
+       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
 
-       return true;
+       throw BaseException(std::string("Database backend ") + name + " not supported.");
 }
-#endif
 
 void ServerMap::beginSave()
 {
@@ -3340,13 +1936,13 @@ bool ServerMap::saveBlock(MapBlock *block)
        return saveBlock(block, dbase);
 }
 
-bool ServerMap::saveBlock(MapBlock *block, Database *db)
+bool ServerMap::saveBlock(MapBlock *block, MapDatabase *db)
 {
        v3s16 p3d = block->getPos();
 
        // Dummy blocks are not written
        if (block->isDummy()) {
-               errorstream << "WARNING: saveBlock: Not writing dummy block "
+               warningstream << "saveBlock: Not writing dummy block "
                        << PP(p3d) << std::endl;
                return true;
        }
@@ -3362,25 +1958,21 @@ bool ServerMap::saveBlock(MapBlock *block, Database *db)
        o.write((char*) &version, 1);
        block->serialize(o, version, true);
 
-       std::string data = o.str();
-       bool ret = db->saveBlock(p3d, data);
-       if(ret) {
+       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(std::string sectordir, std::string blockfile,
+void ServerMap::loadBlock(const std::string &sectordir, const std::string &blockfile,
                MapSector *sector, bool save_after_load)
 {
-       DSTACK(__FUNCTION_NAME);
-
-       std::string fullpath = sectordir+DIR_DELIM+blockfile;
+       std::string fullpath = sectordir + DIR_DELIM + blockfile;
        try {
-
                std::ifstream is(fullpath.c_str(), std::ios_base::binary);
-               if(is.good() == false)
+               if (!is.good())
                        throw FileNotGoodException("Cannot open block file");
 
                v3s16 p3d = getBlockPos(sectordir, blockfile);
@@ -3415,8 +2007,11 @@ void ServerMap::loadBlock(std::string sectordir, std::string blockfile,
                block->deSerialize(is, version, true);
 
                // If it's a new block, insert it to the map
-               if(created_new)
+               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
@@ -3436,13 +2031,13 @@ void ServerMap::loadBlock(std::string sectordir, std::string blockfile,
        }
        catch(SerializationError &e)
        {
-               infostream<<"WARNING: Invalid block data on disk "
+               warningstream<<"Invalid block data on disk "
                                <<"fullpath="<<fullpath
                                <<" (SerializationError). "
                                <<"what()="<<e.what()
                                <<std::endl;
                                // Ignoring. A new one will be generated.
-               assert(0);
+               abort();
 
                // TODO: Backup file; name is in fullpath.
        }
@@ -3450,8 +2045,6 @@ void ServerMap::loadBlock(std::string sectordir, std::string blockfile,
 
 void ServerMap::loadBlock(std::string *blob, v3s16 p3d, MapSector *sector, bool save_after_load)
 {
-       DSTACK(__FUNCTION_NAME);
-
        try {
                std::istringstream is(*blob, std::ios_base::binary);
 
@@ -3462,13 +2055,6 @@ void ServerMap::loadBlock(std::string *blob, v3s16 p3d, MapSector *sector, bool
                        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);
@@ -3482,8 +2068,11 @@ void ServerMap::loadBlock(std::string *blob, v3s16 p3d, MapSector *sector, bool
                block->deSerialize(is, version, true);
 
                // If it's a new block, insert it to the map
-               if(created_new)
+               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
@@ -3496,7 +2085,6 @@ void ServerMap::loadBlock(std::string *blob, v3s16 p3d, MapSector *sector, bool
 
                // We just loaded it from, so it's up-to-date.
                block->resetModified();
-
        }
        catch(SerializationError &e)
        {
@@ -3512,80 +2100,95 @@ void ServerMap::loadBlock(std::string *blob, v3s16 p3d, MapSector *sector, bool
                                        <<"(ignore_world_load_errors)"<<std::endl;
                } else {
                        throw SerializationError("Invalid block data in database");
-                       //assert(0);
                }
        }
 }
 
 MapBlock* ServerMap::loadBlock(v3s16 blockpos)
 {
-       DSTACK(__FUNCTION_NAME);
+       bool created_new = (getBlockNoCreateNoEx(blockpos) == NULL);
 
        v2s16 p2d(blockpos.X, blockpos.Z);
 
        std::string ret;
-
-       ret = dbase->loadBlock(blockpos);
-       if (ret != "") {
+       dbase->loadBlock(blockpos, &ret);
+       if (!ret.empty()) {
                loadBlock(&ret, blockpos, createSector(p2d), false);
-               return getBlockNoCreateNoEx(blockpos);
-       }
-       // 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.
-       int loadlayout = 1;
-       std::string sectordir1 = getSectorDir(p2d, 1);
-       std::string sectordir;
-       if(fs::PathExists(sectordir1))
-       {
-               sectordir = sectordir1;
-       }
-       else
-       {
-               loadlayout = 2;
-               sectordir = getSectorDir(p2d, 2);
-       }
-
-       /*
-               Make sure sector is loaded
-       */
-       MapSector *sector = getSectorNoGenerateNoEx(p2d);
-       if(sector == NULL)
-       {
-               try{
-                       sector = loadSectorMeta(sectordir, loadlayout != 2);
+       } else if (dbase_ro) {
+               dbase_ro->loadBlock(blockpos, &ret);
+               if (!ret.empty()) {
+                       loadBlock(&ret, blockpos, createSector(p2d), false);
                }
-               catch(InvalidFilenameException &e)
-               {
-                       return NULL;
-               }
-               catch(FileNotGoodException &e)
-               {
-                       return NULL;
+       } 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);
                }
-               catch(std::exception &e)
-               {
+
+               /*
+               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;
+}
 
-       /*
-               Make sure file exists
-       */
+bool ServerMap::deleteBlock(v3s16 blockpos)
+{
+       if (!dbase->deleteBlock(blockpos))
+               return false;
 
-       std::string blockfilename = getBlockFilename(blockpos);
-       if(fs::PathExists(sectordir+DIR_DELIM+blockfilename) == false)
-               return NULL;
+       MapBlock *block = getBlockNoCreateNoEx(blockpos);
+       if (block) {
+               v2s16 p2d(blockpos.X, blockpos.Z);
+               MapSector *sector = getSectorNoGenerateNoEx(p2d);
+               if (!sector)
+                       return false;
+               sector->deleteBlock(block);
+       }
 
-       /*
-               Load block and save it to the database
-       */
-       loadBlock(sectordir, blockfilename, sector, true);
-       return getBlockNoCreateNoEx(blockpos);
+       return true;
 }
 
 void ServerMap::PrintInfo(std::ostream &out)
@@ -3593,15 +2196,19 @@ void ServerMap::PrintInfo(std::ostream &out)
        out<<"ServerMap: ";
 }
 
-MMVManip::MMVManip(Map *map):
-               VoxelManipulator(),
-               m_is_dirty(false),
-               m_create_area(false),
-               m_map(map)
+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()
+MMVManip::MMVManip(Map *map):
+               VoxelManipulator(),
+               m_map(map)
 {
 }
 
@@ -3643,7 +2250,7 @@ void MMVManip::initialEmerge(v3s16 blockpos_min, v3s16 blockpos_max,
                bool block_data_inexistent = false;
                try
                {
-                       TimeTaker timer1("emerge load", &emerge_load_time);
+                       TimeTaker timer2("emerge load", &emerge_load_time);
 
                        block = m_map->getBlockNoCreate(p);
                        if(block->isDummy())
@@ -3659,7 +2266,7 @@ void MMVManip::initialEmerge(v3s16 blockpos_min, v3s16 blockpos_max,
                if(block_data_inexistent)
                {
 
-                       if (load_if_inexistent) {
+                       if (load_if_inexistent && !blockpos_over_max_limit(p)) {
                                ServerMap *svrmap = (ServerMap *)m_map;
                                block = svrmap->emergeBlock(p, false);
                                if (block == NULL)
@@ -3702,18 +2309,16 @@ void MMVManip::blitBackAll(std::map<v3s16, MapBlock*> *modified_blocks,
        /*
                Copy data of all blocks
        */
-       for(std::map<v3s16, u8>::iterator
-                       i = m_loaded_blocks.begin();
-                       i != m_loaded_blocks.end(); ++i)
-       {
-               v3s16 p = i->first;
+       for (auto &loaded_block : m_loaded_blocks) {
+               v3s16 p = loaded_block.first;
                MapBlock *block = m_map->getBlockNoCreateNoEx(p);
-               bool existed = !(i->second & VMANIP_BLOCK_DATA_INEXIST);
-               if ((existed == false) || (block == NULL) ||
-                       (overwrite_generated == false && block->isGenerated() == true))
+               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;