text: /*
  Minetest
  Copyright (C) 2010-2013 celeron55, Perttu Ahola <celeron55@gmail.com>
  Copyright (C) 2010-2013 kwolekr, Ryan Kwolek <kwolekr@minetest.net>
  
  This program is free software; you can redistribute it and/or modify
  it under the terms of the GNU Lesser General Public License as published by
  the Free Software Foundation; either version 2.1 of the License, or
  (at your option) any later version.
  
  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU Lesser General Public License for more details.
  
  You should have received a copy of the GNU Lesser General Public License along
  with this program; if not, write to the Free Software Foundation, Inc.,
  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
  
  
  #include "emerge.h"
  
  #include <iostream>
  #include <queue>
  
  #include "util/container.h"
  #include "util/thread.h"
  #include "threading/event.h"
  
  #include "config.h"
  #include "constants.h"
  #include "environment.h"
  #include "log.h"
  #include "map.h"
  #include "mapblock.h"
  #include "mg_biome.h"
  #include "mg_ore.h"
  #include "mg_decoration.h"
  #include "mg_schematic.h"
  #include "nodedef.h"
  #include "profiler.h"
  #include "scripting_server.h"
  #include "server.h"
  #include "serverobject.h"
  #include "settings.h"
  #include "voxel.h"
  
  class EmergeThread : public Thread {
  public:
  	bool enable_mapgen_debug_info;
  	int id;
  
  	EmergeThread(Server *server, int ethreadid);
  	~EmergeThread();
  
  	void *run();
  	void signal();
  
  	// Requires queue mutex held
  	bool pushBlock(v3s16 pos);
  
  	void cancelPendingItems();
  
  	static void runCompletionCallbacks(
  		v3s16 pos, EmergeAction action,
  		const EmergeCallbackList &callbacks);
  
  private:
  	Server *m_server;
  	ServerMap *m_map;
  	EmergeManager *m_emerge;
  	Mapgen *m_mapgen;
  
  	Event m_queue_event;
  	std::queue<v3s16> m_block_queue;
  
  	bool popBlockEmerge(v3s16 *pos, BlockEmergeData *bedata);
  
  	EmergeAction getBlockOrStartGen(
  		v3s16 pos, bool allow_gen, MapBlock **block, BlockMakeData *data);
  	MapBlock *finishGen(v3s16 pos, BlockMakeData *bmdata,
  		std::map<v3s16, MapBlock *> *modified_blocks);
  
  	friend class EmergeManager;
  };
  
  ////
  //// EmergeManager
  ////
  
  EmergeManager::EmergeManager(Server *server)
  {
  	this->ndef      = server->getNodeDefManager();
  	this->biomemgr  = new BiomeManager(server);
  	this->oremgr    = new OreManager(server);
  	this->decomgr   = new DecorationManager(server);
  	this->schemmgr  = new SchematicManager(server);
  	this->gen_notify_on = 0;
  
  	// Note that accesses to this variable are not synchronized.
  	// This is because the *only* thread ever starting or stopping
  	// EmergeThreads should be the ServerThread.
  	this->m_threads_active = false;
  
  	enable_mapgen_debug_info = g_settings->getBool("enable_mapgen_debug_info");
  
  	// If unspecified, leave a proc for the main thread and one for
  	// some other misc thread
  	s16 nthreads = 0;
  	if (!g_settings->getS16NoEx("num_emerge_threads", nthreads))
  		nthreads = Thread::getNumberOfProcessors() - 2;
  	if (nthreads < 1)
  		nthreads = 1;
  
  	m_qlimit_total = g_settings->getU16("emergequeue_limit_total");
  	if (!g_settings->getU16NoEx("emergequeue_limit_diskonly", m_qlimit_diskonly))
  		m_qlimit_diskonly = nthreads * 5 + 1;
  	if (!g_settings->getU16NoEx("emergequeue_limit_generate", m_qlimit_generate))
  		m_qlimit_generate = nthreads + 1;
  
  	// don't trust user input for something very important like this
  	if (m_qlimit_total < 1)
  		m_qlimit_total = 1;
  	if (m_qlimit_diskonly < 1)
  		m_qlimit_diskonly = 1;
  	if (m_qlimit_generate < 1)
  		m_qlimit_generate = 1;
  
  	for (s16 i = 0; i < nthreads; i++)
  		m_threads.push_back(new EmergeThread(server, i));
  
  	infostream << "EmergeManager: using " << nthreads << " threads" << std::endl;
  }
  
  
  EmergeManager::~EmergeManager()
  {
  	for (u32 i = 0; i != m_threads.size(); i++) {
  		EmergeThread *thread = m_threads[i];
  
  		if (m_threads_active) {
  			thread->stop();
  			thread->signal();
  			thread->wait();
  		}
  
  		delete thread;
  		delete m_mapgens[i];
  	}
  
  	delete biomemgr;
  	delete oremgr;
  	delete decomgr;
  	delete schemmgr;
  }
  
  
  bool EmergeManager::initMapgens(MapgenParams *params)
  {
  	if (m_mapgens.size())
  		return false;
  
  	this->mgparams = params;
  
  	for (u32 i = 0; i != m_threads.size(); i++) {
  		Mapgen *mg = Mapgen::createMapgen(params->mgtype, i, params, this);
  		m_mapgens.push_back(mg);
  	}
  
  	return true;
  }
  
  
  Mapgen *EmergeManager::getCurrentMapgen()
  {
  	if (!m_threads_active)
  		return NULL;
  
  	for (u32 i = 0; i != m_threads.size(); i++) {
  		if (m_threads[i]->isCurrentThread())
  			return m_threads[i]->m_mapgen;
  	}
  
  	return NULL;
  }
  
  
  void EmergeManager::startThreads()
  {
  	if (m_threads_active)
  		return;
  
  	for (u32 i = 0; i != m_threads.size(); i++)
  		m_threads[i]->start();
  
  	m_threads_active = true;
  }
  
  
  void EmergeManager::stopThreads()
  {
  	if (!m_threads_active)
  		return;
  
  	// Request thread stop in parallel
  	for (u32 i = 0; i != m_threads.size(); i++) {
  		m_threads[i]->stop();
  		m_threads[i]->signal();
  	}
  
  	// Then do the waiting for each
  	for (u32 i = 0; i != m_threads.size(); i++)
  		m_threads[i]->wait();
  
  	m_threads_active = false;
  }
  
  
  bool EmergeManager::isRunning()
  {
  	return m_threads_active;
  }
  
  
  bool EmergeManager::enqueueBlockEmerge(
  	u16 peer_id,
  	v3s16 blockpos,
  	bool allow_generate,
  	bool ignore_queue_limits)
  {
  	u16 flags = 0;
  	if (allow_generate)
  		flags |= BLOCK_EMERGE_ALLOW_GEN;
  	if (ignore_queue_limits)
  		flags |= BLOCK_EMERGE_FORCE_QUEUE;
  
  	return enqueueBlockEmergeEx(blockpos, peer_id, flags, NULL, NULL);
  }
  
  
  bool EmergeManager::enqueueBlockEmergeEx(
  	v3s16 blockpos,
  	u16 peer_id,
  	u16 flags,
  	EmergeCompletionCallback callback,
  	void *callback_param)
  {
  	EmergeThread *thread = NULL;
  	bool entry_already_exists = false;
  
  	{
  		MutexAutoLock queuelock(m_queue_mutex);
  
  		if (!pushBlockEmergeData(blockpos, peer_id, flags,
  				callback, callback_param, &entry_already_exists))
  			return false;
  
  		if (entry_already_exists)
  			return true;
  
  		thread = getOptimalThread();
  		thread->pushBlock(blockpos);
  	}
  
  	thread->signal();
  
  	return true;
  }
  
  
  //
  // Mapgen-related helper functions
  //
  
  
  // TODO(hmmmm): Move this to ServerMap
  v3s16 EmergeManager::getContainingChunk(v3s16 blockpos)
  {
  	return getContainingChunk(blockpos, mgparams->chunksize);
  }
  
  // TODO(hmmmm): Move this to ServerMap
  v3s16 EmergeManager::getContainingChunk(v3s16 blockpos, s16 chunksize)
  {
  	s16 coff = -chunksize / 2;
  	v3s16 chunk_offset(coff, coff, coff);
  
  	return getContainerPos(blockpos - chunk_offset, chunksize)
  		* chunksize + chunk_offset;
  }
  
  
  int EmergeManager::getSpawnLevelAtPoint(v2s16 p)
  {
  	if (m_mapgens.size() == 0 || !m_mapgens[0]) {
  		errorstream << "EmergeManager: getSpawnLevelAtPoint() called"
  			" before mapgen init" << std::endl;
  		return 0;
  	}
  
  	return m_mapgens[0]->getSpawnLevelAtPoint(p);
  }
  
  
  int EmergeManager::getGroundLevelAtPoint(v2s16 p)
  {
  	if (m_mapgens.size() == 0 || !m_mapgens[0]) {
  		errorstream << "EmergeManager: getGroundLevelAtPoint() called"
  			" before mapgen init" << std::endl;
  		return 0;
  	}
  
  	return m_mapgens[0]->getGroundLevelAtPoint(p);
  }
  
  // TODO(hmmmm): Move this to ServerMap
  bool EmergeManager::isBlockUnderground(v3s16 blockpos)
  {
  #if 0
  	v2s16 p = v2s16((blockpos.X * MAP_BLOCKSIZE) + MAP_BLOCKSIZE / 2,
  					(blockpos.Y * MAP_BLOCKSIZE) + MAP_BLOCKSIZE / 2);
  	int ground_level = getGroundLevelAtPoint(p);
  	return blockpos.Y * (MAP_BLOCKSIZE + 1) <= min(water_level, ground_level);
  #endif
  
  	// Use a simple heuristic; the above method is wildly inaccurate anyway.
  	return blockpos.Y * (MAP_BLOCKSIZE + 1) <= mgparams->water_level;
  }
  
  bool EmergeManager::pushBlockEmergeData(
  	v3s16 pos,
  	u16 peer_requested,
  	u16 flags,
  	EmergeCompletionCallback callback,
  	void *callback_param,
  	bool *entry_already_exists)
  {
  	u16 &count_peer = m_peer_queue_count[peer_requested];
  
  	if ((flags & BLOCK_EMERGE_FORCE_QUEUE) == 0) {
  		if (m_blocks_enqueued.size() >= m_qlimit_total)
  			return false;
  
  		if (peer_requested != PEER_ID_INEXISTENT) {
  			u16 qlimit_peer = (flags & BLOCK_EMERGE_ALLOW_GEN) ?
  				m_qlimit_generate : m_qlimit_diskonly;
  			if (count_peer >= qlimit_peer)
  				return false;
  		}
  	}
  
  	std::pair<std::map<v3s16, BlockEmergeData>::iterator, bool> findres;
  	findres = m_blocks_enqueued.insert(std::make_pair(pos, BlockEmergeData()));
  
  	BlockEmergeData &bedata = findres.first->second;
  	*entry_already_exists   = !findres.second;
  
  	if (callback)
  		bedata.callbacks.push_back(std::make_pair(callback, callback_param));
  
  	if (*entry_already_exists) {
  		bedata.flags |= flags;
  	} else {
  		bedata.flags = flags;
  		bedata.peer_requested = peer_requested;
  
  		count_peer++;
  	}
  
  	return true;
  }
  
  
  bool EmergeManager::popBlockEmergeData(v3s16 pos, BlockEmergeData *bedata)
  {
  	std::map<v3s16, BlockEmergeData>::iterator it;
  	UNORDERED_MAP<u16, u16>::iterator it2;
  
  	it = m_blocks_enqueued.find(pos);
  	if (it == m_blocks_enqueued.end())
  		return false;
  
  	*bedata = it->second;
  
  	it2 = m_peer_queue_count.find(bedata->peer_requested);
  	if (it2 == m_peer_queue_count.end())
  		return false;
  
  	u16 &count_peer = it2->second;
  	assert(count_peer != 0);
  	count_peer--;
  
  	m_blocks_enqueued.erase(it);
  
  	return true;
  }
  
  
  EmergeThread *EmergeManager::getOptimalThread()
  {
  	size_t nthreads = m_threads.size();
  
  	FATAL_ERROR_IF(nthreads == 0, "No emerge threads!");
  
  	size_t index = 0;
  	size_t nitems_lowest = m_threads[0]->m_block_queue.size();
  
  	for (size_t i = 1; i < nthreads; i++) {
  		size_t nitems = m_threads[i]->m_block_queue.size();
  		if (nitems < nitems_lowest) {
  			index = i;
  			nitems_lowest = nitems;
  		}
  	}
  
  	return m_threads[index];
  }
  
  
  ////
  //// EmergeThread
  ////
  
  EmergeThread::EmergeThread(Server *server, int ethreadid) :
  	enable_mapgen_debug_info(false),
  	id(ethreadid),
  	m_server(server),
  	m_map(NULL),
  	m_emerge(NULL),
  	m_mapgen(NULL)
  {
  	m_name = "Emerge-" + itos(ethreadid);
  }
  
  
  EmergeThread::~EmergeThread()
  {
  	//cancelPendingItems();
  }
  
  
  void EmergeThread::signal()
  {
  	m_queue_event.signal();
  }
  
  
  bool EmergeThread::pushBlock(v3s16 pos)
  {
  	m_block_queue.push(pos);
  	return true;
  }
  
  
  void EmergeThread::cancelPendingItems()
  {
  	MutexAutoLock queuelock(m_emerge->m_queue_mutex);
  
  	while (!m_block_queue.empty()) {
  		BlockEmergeData bedata;
  		v3s16 pos;
  
  		pos = m_block_queue.front();
  		m_block_queue.pop();
  
  		m_emerge->popBlockEmergeData(pos, &bedata);
  
  		runCompletionCallbacks(pos, EMERGE_CANCELLED, bedata.callbacks);
  	}
  }
  
  
  void EmergeThread::runCompletionCallbacks(
  	v3s16 pos,
  	EmergeAction action,
  	const EmergeCallbackList &callbacks)
  {
  	for (size_t i = 0; i != callbacks.size(); i++) {
  		EmergeCompletionCallback callback;
  		void *param;
  
  		callback = callbacks[i].first;
  		param    = callbacks[i].second;
  
  		callback(pos, action, param);
  	}
  }
  
  
  bool EmergeThread::popBlockEmerge(v3s16 *pos, BlockEmergeData *bedata)
  {
  	MutexAutoLock queuelock(m_emerge->m_queue_mutex);
  
  	if (m_block_queue.empty())
  		return false;
  
  	*pos = m_block_queue.front();
  	m_block_queue.pop();
  
  	m_emerge->popBlockEmergeData(*pos, bedata);
  
  	return true;
  }
  
  
  EmergeAction EmergeThread::getBlockOrStartGen(
  	v3s16 pos, bool allow_gen, MapBlock **block, BlockMakeData *bmdata)
  {
  	MutexAutoLock envlock(m_server->m_env_mutex);
  
  	// 1). Attempt to fetch block from memory
  	*block = m_map->getBlockNoCreateNoEx(pos);
  	if (*block && !(*block)->isDummy()) {
  		if ((*block)->isGenerated())
  			return EMERGE_FROM_MEMORY;
  	} else {
  		// 2). Attempt to load block from disk if it was not in the memory
  		*block = m_map->loadBlock(pos);
  		if (*block && (*block)->isGenerated())
  			return EMERGE_FROM_DISK;
  	}
  
  	// 3). Attempt to start generation
  	if (allow_gen && m_map->initBlockMake(pos, bmdata))
  		return EMERGE_GENERATED;
  
  	// All attempts failed; cancel this block emerge
  	return EMERGE_CANCELLED;
  }
  
  
  MapBlock *EmergeThread::finishGen(v3s16 pos, BlockMakeData *bmdata,
  	std::map<v3s16, MapBlock *> *modified_blocks)
  {
  	MutexAutoLock envlock(m_server->m_env_mutex);
  	ScopeProfiler sp(g_profiler,
  		"EmergeThread: after Mapgen::makeChunk", SPT_AVG);
  
  	/*
  		Perform post-processing on blocks (invalidate lighting, queue liquid
  		transforms, etc.) to finish block make
  	*/
  	m_map->finishBlockMake(bmdata, modified_blocks);
  
  	MapBlock *block = m_map->getBlockNoCreateNoEx(pos);
  	if (!block) {
  		errorstream << "EmergeThread::finishGen: Couldn't grab block we "
  			"just generated: " << PP(pos) << std::endl;
  		return NULL;
  	}
  
  	v3s16 minp = bmdata->blockpos_min * MAP_BLOCKSIZE;
  	v3s16 maxp = bmdata->blockpos_max * MAP_BLOCKSIZE +
  				 v3s16(1,1,1) * (MAP_BLOCKSIZE - 1);
  
  	// Ignore map edit events, they will not need to be sent
  	// to anybody because the block hasn't been sent to anybody
  	MapEditEventAreaIgnorer ign(
  		&m_server->m_ignore_map_edit_events_area,
  		VoxelArea(minp, maxp));
  
  	/*
  		Run Lua on_generated callbacks
  	*/
  	try {
  		m_server->getScriptIface()->environment_OnGenerated(
  			minp, maxp, m_mapgen->blockseed);
  	} catch (LuaError &e) {
  		m_server->setAsyncFatalError("Lua: finishGen" + std::string(e.what()));
  	}
  
  	EMERGE_DBG_OUT("ended up with: " << analyze_block(block));
  
  	/*
  		Activate the block
  	*/
  	m_server->m_env->activateBlock(block, 0);
  
  	return block;
  }
  
  
  void *EmergeThread::run()
  {
  	DSTACK(FUNCTION_NAME);
  	BEGIN_DEBUG_EXCEPTION_HANDLER
  
  	v3s16 pos;
  
  	m_map    = (ServerMap *)&(m_server->m_env->getMap());
  	m_emerge = m_server->m_emerge;
  	m_mapgen = m_emerge->m_mapgens[id];
  	enable_mapgen_debug_info = m_emerge->enable_mapgen_debug_info;
  
  	try {
  	while (!stopRequested()) {
  		std::map<v3s16, MapBlock *> modified_blocks;
  		BlockEmergeData bedata;
  		BlockMakeData bmdata;
  		EmergeAction action;
  		MapBlock *block;
  
  		if (!popBlockEmerge(&pos, &bedata)) {
  			m_queue_event.wait();
  			continue;
  		}
  
  		if (blockpos_over_max_limit(pos))
  			continue;
  
  		bool allow_gen = bedata.flags & BLOCK_EMERGE_ALLOW_GEN;
  		EMERGE_DBG_OUT("pos=" PP(pos) " allow_gen=" << allow_gen);
  
  		action = getBlockOrStartGen(pos, allow_gen, &block, &bmdata);
  		if (action == EMERGE_GENERATED) {
  			{
  				ScopeProfiler sp(g_profiler,
  					"EmergeThread: Mapgen::makeChunk", SPT_AVG);
  				TimeTaker t("mapgen::make_block()");
  
  				m_mapgen->makeChunk(&bmdata);
  
  				if (enable_mapgen_debug_info == false)
  					t.stop(true); // Hide output
  			}
  
  			block = finishGen(pos, &bmdata, &modified_blocks);
  		}
  
  		runCompletionCallbacks(pos, action, bedata.callbacks);
  
  		if (block)
  			modified_blocks[pos] = block;
  
  		if (modified_blocks.size() > 0)
  			m_server->SetBlocksNotSent(modified_blocks);
  	}
  	} catch (VersionMismatchException &e) {
  		std::ostringstream err;
  		err << "World data version mismatch in MapBlock " << PP(pos) << std::endl
  			<< "----" << std::endl
  			<< "\"" << e.what() << "\"" << std::endl
  			<< "See debug.txt." << std::endl
  			<< "World probably saved by a newer version of " PROJECT_NAME_C "."
  			<< std::endl;
  		m_server->setAsyncFatalError(err.str());
  	} catch (SerializationError &e) {
  		std::ostringstream err;
  		err << "Invalid data in MapBlock " << PP(pos) << std::endl
  			<< "----" << std::endl
  			<< "\"" << e.what() << "\"" << std::endl
  			<< "See debug.txt." << std::endl
  			<< "You can ignore this using [ignore_world_load_errors = true]."
  			<< std::endl;
  		m_server->setAsyncFatalError(err.str());
  	}
  
  	END_DEBUG_EXCEPTION_HANDLER
  	return NULL;
  }
  