void EmergeManager::initMapgens()
{
	if (m_mapgens.size())
		return;

	MapgenFactory *mgfactory = getMapgenFactory(params.mg_name);
	if (!mgfactory) {
		errorstream << "EmergeManager: mapgen " << params.mg_name <<
			" not registered; falling back to " << DEFAULT_MAPGEN << std::endl;

		params.mg_name = DEFAULT_MAPGEN;

		mgfactory = getMapgenFactory(params.mg_name);
		FATAL_ERROR_IF(mgfactory == NULL, "Couldn't use any mapgen!");
	}

	if (!params.sparams) {
		params.sparams = mgfactory->createMapgenParams();
		params.sparams->readParams(g_settings);
	}

	for (u32 i = 0; i != m_threads.size(); i++) {
		Mapgen *mg = mgfactory->createMapgen(i, &params, this);
		m_mapgens.push_back(mg);
	}
}

void CNodeDefManager::serialize(std::ostream &os, u16 protocol_version) const
{
	writeU8(os, 1); // version
	u16 count = 0;
	std::ostringstream os2(std::ios::binary);
	for (u32 i = 0; i < m_content_features.size(); i++) {
		if (i == CONTENT_IGNORE || i == CONTENT_AIR
				|| i == CONTENT_UNKNOWN)
			continue;
		const ContentFeatures *f = &m_content_features[i];
		if (f->name == "")
			continue;
		writeU16(os2, i);
		// Wrap it in a string to allow different lengths without
		// strict version incompatibilities
		std::ostringstream wrapper_os(std::ios::binary);
		f->serialize(wrapper_os, protocol_version);
		os2<<serializeString(wrapper_os.str());

		// must not overflow
		u16 next = count + 1;
		FATAL_ERROR_IF(next < count, "Overflow");
		count++;
	}
	writeU16(os, count);
	os << serializeLongString(os2.str());
}

bool GUIEngine::setTexture(texture_layer layer, std::string texturepath,
		bool tile_image, unsigned int minsize)
{
	video::IVideoDriver* driver = m_device->getVideoDriver();
	FATAL_ERROR_IF(driver == 0, "Could not get video driver");

	if (m_textures[layer].texture != NULL)
	{
		driver->removeTexture(m_textures[layer].texture);
		m_textures[layer].texture = NULL;
	}

	if ((texturepath == "") || !fs::PathExists(texturepath))
	{
		return false;
	}

	m_textures[layer].texture = driver->getTexture(texturepath.c_str());
	m_textures[layer].tile    = tile_image;
	m_textures[layer].minsize = minsize;

	if (m_textures[layer].texture == NULL)
	{
		return false;
	}

	return true;
}

scene::IAnimatedMesh* Client::getMesh(const std::string &filename)
{
	StringMap::const_iterator it = m_mesh_data.find(filename);
	if (it == m_mesh_data.end()) {
		errorstream << "Client::getMesh(): Mesh not found: \"" << filename
			<< "\"" << std::endl;
		return NULL;
	}
	const std::string &data    = it->second;
	scene::ISceneManager *smgr = m_device->getSceneManager();

	// Create the mesh, remove it from cache and return it
	// This allows unique vertex colors and other properties for each instance
	Buffer<char> data_rw(data.c_str(), data.size()); // Const-incorrect Irrlicht
	io::IFileSystem *irrfs = m_device->getFileSystem();
	io::IReadFile *rfile   = irrfs->createMemoryReadFile(
			*data_rw, data_rw.getSize(), filename.c_str());
	FATAL_ERROR_IF(!rfile, "Could not create/open RAM file");

	scene::IAnimatedMesh *mesh = smgr->getMesh(rfile);
	rfile->drop();
	// NOTE: By playing with Irrlicht refcounts, maybe we could cache a bunch
	// of uniquely named instances and re-use them
	mesh->grab();
	smgr->getMeshCache()->removeMesh(mesh);
	return mesh;
}

// Push the list of callbacks (a lua table).
// Then push nargs arguments.
// Then call this function, which
// - runs the callbacks
// - replaces the table and arguments with the return value,
//     computed depending on mode
void ScriptApiBase::runCallbacksRaw(int nargs,
		RunCallbacksMode mode, const char *fxn)
{
	lua_State *L = getStack();
	FATAL_ERROR_IF(lua_gettop(L) < nargs + 1, "Not enough arguments");

	// Insert error handler
	lua_pushcfunction(L, script_error_handler);
	int errorhandler = lua_gettop(L) - nargs - 1;
	lua_insert(L, errorhandler);

	// Insert run_callbacks between error handler and table
	lua_getglobal(L, "core");
	lua_getfield(L, -1, "run_callbacks");
	lua_remove(L, -2);
	lua_insert(L, errorhandler + 1);

	// Insert mode after table
	lua_pushnumber(L, (int)mode);
	lua_insert(L, errorhandler + 3);

	// Stack now looks like this:
	// ... <error handler> <run_callbacks> <table> <mode> <arg#1> <arg#2> ... <arg#n>

	int result = lua_pcall(L, nargs + 2, 1, errorhandler);
	if (result != 0)
		scriptError(result, fxn);

	lua_remove(L, -2); // Remove error handler
}

int ModApiUtil::l_request_insecure_environment(lua_State *L)
{
	NO_MAP_LOCK_REQUIRED;

	// Just return _G if security is disabled
	if (!ScriptApiSecurity::isSecure(L)) {
		lua_getglobal(L, "_G");
		return 1;
	}

	// We have to make sure that this function is being called directly by
	// a mod, otherwise a malicious mod could override this function and
	// steal its return value.
	lua_Debug info;
	// Make sure there's only one item below this function on the stack...
	if (lua_getstack(L, 2, &info)) {
		return 0;
	}
	FATAL_ERROR_IF(!lua_getstack(L, 1, &info), "lua_getstack() failed");
	FATAL_ERROR_IF(!lua_getinfo(L, "S", &info), "lua_getinfo() failed");
	// ...and that that item is the main file scope.
	if (strcmp(info.what, "main") != 0) {
		return 0;
	}

	// Get mod name
	lua_rawgeti(L, LUA_REGISTRYINDEX, CUSTOM_RIDX_CURRENT_MOD_NAME);
	if (!lua_isstring(L, -1)) {
		return 0;
	}

	// Check secure.trusted_mods
	const char *mod_name = lua_tostring(L, -1);
	std::string trusted_mods = g_settings->get("secure.trusted_mods");
	trusted_mods.erase(std::remove_if(trusted_mods.begin(),
			trusted_mods.end(), static_cast<int(*)(int)>(&std::isspace)),
			trusted_mods.end());
	std::vector<std::string> mod_list = str_split(trusted_mods, ',');
	if (std::find(mod_list.begin(), mod_list.end(), mod_name) ==
			mod_list.end()) {
		return 0;
	}

	// Push insecure environment
	lua_rawgeti(L, LUA_REGISTRYINDEX, CUSTOM_RIDX_GLOBALS_BACKUP);
	return 1;
}

const char *getHomeOrFail()
{
	const char *home = getenv("HOME");
	// In rare cases the HOME environment variable may be unset
	FATAL_ERROR_IF(!home,
		"Required environment variable HOME is not set");
	return home;
}

ClientEvent *Client::getClientEvent()
{
	FATAL_ERROR_IF(m_client_event_queue.empty(),
			"Cannot getClientEvent, queue is empty.");

	ClientEvent *event = m_client_event_queue.front();
	m_client_event_queue.pop();
	return event;
}

bool setSystemPaths()
{
	char buf[BUFSIZ];

	// Find path of executable and set path_share relative to it
	FATAL_ERROR_IF(!getCurrentExecPath(buf, sizeof(buf)),
		"Failed to get current executable path");
	pathRemoveFile(buf, '\\');

	// Use ".\bin\.."
	path_share = std::string(buf) + "\\..";

	// Use "C:\Documents and Settings\user\Application Data\<PROJECT_NAME>"
	DWORD len = GetEnvironmentVariable("APPDATA", buf, sizeof(buf));
	FATAL_ERROR_IF(len == 0 || len > sizeof(buf), "Failed to get APPDATA");

	path_user = std::string(buf) + DIR_DELIM + PROJECT_NAME;
	return true;
}

// Call lower level SRP code to generate a verifier with the
// given pointers. Contains the preparations, call parameters
// and error checking common to all srp verifier generation code.
// See docs of srp_create_salted_verification_key for more info.
static inline void gen_srp_v(const std::string &name,
	const std::string &password, char **salt, size_t *salt_len,
	char **bytes_v, size_t *len_v)
{
	std::string n_name = lowercase(name);
	SRP_Result res = srp_create_salted_verification_key(SRP_SHA256, SRP_NG_2048,
		n_name.c_str(), (const unsigned char *)password.c_str(),
		password.size(), (unsigned char **)salt, salt_len,
		(unsigned char **)bytes_v, len_v, NULL, NULL);
	FATAL_ERROR_IF(res != SRP_OK, "Couldn't create salted SRP verifier");
}

void ClientEnvironment::setLocalPlayer(LocalPlayer *player)
{
	DSTACK(FUNCTION_NAME);
	/*
		It is a failure if already is a local player
	*/
	FATAL_ERROR_IF(m_local_player != NULL,
		"Local player already allocated");

	m_local_player = player;
}

unsigned int FontEngine::getTextHeight(unsigned int font_size, FontMode mode)
{
	irr::gui::IGUIFont* font = getFont(font_size, mode);

	// use current skin font as fallback
	if (font == NULL) {
		font = m_env->getSkin()->getFont();
	}
	FATAL_ERROR_IF(font == NULL, "Could not get skin font");

	return font->getDimension(L"Some unimportant example String").Height;
}

void Client::startAuth(AuthMechanism chosen_auth_mechanism)
{
	m_chosen_auth_mech = chosen_auth_mechanism;

	switch (chosen_auth_mechanism) {
		case AUTH_MECHANISM_FIRST_SRP: {
			// send srp verifier to server
			NetworkPacket resp_pkt(TOSERVER_FIRST_SRP, 0);
			char *salt, *bytes_v;
			std::size_t len_salt, len_v;
			salt = NULL;
			getSRPVerifier(getPlayerName(), m_password,
				&salt, &len_salt, &bytes_v, &len_v);
			resp_pkt
				<< std::string((char*)salt, len_salt)
				<< std::string((char*)bytes_v, len_v)
				<< (u8)((m_password == "") ? 1 : 0);
			free(salt);
			free(bytes_v);
			Send(&resp_pkt);
			break;
		}
		case AUTH_MECHANISM_SRP:
		case AUTH_MECHANISM_LEGACY_PASSWORD: {
			u8 based_on = 1;

			if (chosen_auth_mechanism == AUTH_MECHANISM_LEGACY_PASSWORD) {
				m_password = translatePassword(getPlayerName(), m_password);
				based_on = 0;
			}

			std::string playername_u = lowercase(getPlayerName());
			m_auth_data = srp_user_new(SRP_SHA256, SRP_NG_2048,
				getPlayerName().c_str(), playername_u.c_str(),
				(const unsigned char *) m_password.c_str(),
				m_password.length(), NULL, NULL);
			char *bytes_A = 0;
			size_t len_A = 0;
			SRP_Result res = srp_user_start_authentication(
				(struct SRPUser *) m_auth_data, NULL, NULL, 0,
				(unsigned char **) &bytes_A, &len_A);
			FATAL_ERROR_IF(res != SRP_OK, "Creating local SRP user failed.");

			NetworkPacket resp_pkt(TOSERVER_SRP_BYTES_A, 0);
			resp_pkt << std::string(bytes_A, len_A) << based_on;
			Send(&resp_pkt);
			break;
		}
		case AUTH_MECHANISM_NONE:
			break; // not handled in this method
	}
}

KeyPress::KeyPress(const char *name)
{
	if (strlen(name) == 0) {
		Key = irr::KEY_KEY_CODES_COUNT;
		Char = L'\0';
		m_name = "";
		return;
	}

	if (strlen(name) <= 4) {
		// Lookup by resulting character
		int chars_read = mbtowc(&Char, name, 1);
		FATAL_ERROR_IF(chars_read != 1, "Unexpected multibyte character");
		try {
			struct table_key k = lookup_keychar(Char);
			m_name = k.Name;
			Key = k.Key;
			return;
		} catch (UnknownKeycode &e) {};
	} else {
		// Lookup by name
		m_name = name;
		try {
			struct table_key k = lookup_keyname(name);
			Key = k.Key;
			Char = k.Char;
			return;
		} catch (UnknownKeycode &e) {};
	}

	// It's not a known key, complain and try to do something
	Key = irr::KEY_KEY_CODES_COUNT;
	int chars_read = mbtowc(&Char, name, 1);
	FATAL_ERROR_IF(chars_read != 1, "Unexpected multibyte character");
	m_name = "";
	warningstream << "KeyPress: Unknown key '" << name << "', falling back to first char.";
}

ScriptApiBase::ScriptApiBase()
{
	#ifdef SCRIPTAPI_LOCK_DEBUG
	m_locked = false;
	#endif

	m_luastack = luaL_newstate();
	FATAL_ERROR_IF(!m_luastack, "luaL_newstate() failed");

	luaL_openlibs(m_luastack);

	// Add and save an error handler
	lua_pushcfunction(m_luastack, script_error_handler);
	m_errorhandler = lua_gettop(m_luastack);

	// Make the ScriptApiBase* accessible to ModApiBase
	lua_pushlightuserdata(m_luastack, this);
	lua_setfield(m_luastack, LUA_REGISTRYINDEX, "scriptapi");

	// If we are using LuaJIT add a C++ wrapper function to catch
	// exceptions thrown in Lua -> C++ calls
#if USE_LUAJIT
	lua_pushlightuserdata(m_luastack, (void*) script_exception_wrapper);
	luaJIT_setmode(m_luastack, -1, LUAJIT_MODE_WRAPCFUNC | LUAJIT_MODE_ON);
	lua_pop(m_luastack, 1);
#endif

	// Add basic globals
	lua_newtable(m_luastack);
	lua_setglobal(m_luastack, "core");

	lua_pushstring(m_luastack, DIR_DELIM);
	lua_setglobal(m_luastack, "DIR_DELIM");

	lua_pushstring(m_luastack, porting::getPlatformName());
	lua_setglobal(m_luastack, "PLATFORM");

	// m_secure gets set to true inside
	// ScriptApiSecurity::initializeSecurity(), if neccessary.
	// Default to false otherwise
	m_secure = false;

	m_server = NULL;
	m_environment = NULL;
	m_guiengine = NULL;
}

	virtual void registerItem(const ItemDefinition &def)
	{
		verbosestream<<"ItemDefManager: registering \""<<def.name<<"\""<<std::endl;
		// Ensure that the "" item (the hand) always has ToolCapabilities
		if (def.name.empty())
			FATAL_ERROR_IF(!def.tool_capabilities, "Hand does not have ToolCapabilities");

		if(m_item_definitions.count(def.name) == 0)
			m_item_definitions[def.name] = new ItemDefinition(def);
		else
			*(m_item_definitions[def.name]) = def;

		// Remove conflicting alias if it exists
		bool alias_removed = (m_aliases.erase(def.name) != 0);
		if(alias_removed)
			infostream<<"ItemDefManager: erased alias "<<def.name
					<<" because item was defined"<<std::endl;
	}

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];
}

void Client::sendInventoryFields(const std::string &formname,
		const StringMap &fields)
{
	size_t fields_size = fields.size();
	FATAL_ERROR_IF(fields_size > 0xFFFF, "Unsupported number of inventory fields");

	NetworkPacket pkt(TOSERVER_INVENTORY_FIELDS, 0);
	pkt << formname << (u16) (fields_size & 0xFFFF);

	StringMap::const_iterator it;
	for (it = fields.begin(); it != fields.end(); ++it) {
		const std::string &name  = it->first;
		const std::string &value = it->second;
		pkt << name;
		pkt.putLongString(value);
	}

	Send(&pkt);
}

std::string ClientMediaDownloader::serializeRequiredHashSet()
{
	std::ostringstream os(std::ios::binary);

	writeU32(os, MTHASHSET_FILE_SIGNATURE); // signature
	writeU16(os, 1);                        // version

	// Write list of hashes of files that have not been
	// received (found in cache) yet
	for (std::map<std::string, FileStatus*>::iterator
			it = m_files.begin();
			it != m_files.end(); ++it) {
		if (!it->second->received) {
			FATAL_ERROR_IF(it->second->sha1.size() != 20, "Invalid SHA1 size");
			os << it->second->sha1;
		}
	}

	return os.str();
}

void Client::sendNodemetaFields(v3s16 p, const std::string &formname,
		const std::map<std::string, std::string> &fields)
{
	size_t fields_size = fields.size();

	FATAL_ERROR_IF(fields_size > 0xFFFF, "Unsupported number of nodemeta fields");

	NetworkPacket pkt(TOSERVER_NODEMETA_FIELDS, 0);

	pkt << p << formname << (u16) (fields_size & 0xFFFF);

	for(std::map<std::string, std::string>::const_iterator
			i = fields.begin(); i != fields.end(); i++) {
		const std::string &name = i->first;
		const std::string &value = i->second;
		pkt << name;
		pkt.putLongString(value);
	}

	Send(&pkt);
}