Add MapSettingsManager and new mapgen setting script API functions

This commit refactors the majority of the Mapgen settings system.
- MapgenParams is now owned by MapSettingsManager, itself a part of ServerMap,
  instead of the EmergeManager.
- New Script API functions added:
    core.get_mapgen_setting
    core.get_mapgen_setting_noiseparams,
    core.set_mapgen_setting, and
    core.set_mapgen_setting_noiseparams.
- minetest.get/set_mapgen_params are deprecated by the above new functions.
- It is now possible to view and modify any arbitrary mapgen setting from a mod,
  rather than the base MapgenParams structure.
- MapgenSpecificParams has been removed.

build/android/jni/Android.mk

@@ -169,6 +169,7 @@ LOCAL_SRC_FILES := \
 		jni/src/log.cpp                           \
 		jni/src/main.cpp                          \
 		jni/src/map.cpp                           \
+		jni/src/map_settings_manager.cpp          \
 		jni/src/mapblock.cpp                      \
 		jni/src/mapblock_mesh.cpp                 \
 		jni/src/mapgen.cpp                        \
@@ -238,6 +239,7 @@ LOCAL_SRC_FILES := \
 		jni/src/unittest/test_connection.cpp      \
 		jni/src/unittest/test_filepath.cpp        \
 		jni/src/unittest/test_inventory.cpp       \
+		jni/src/unittest/test_map_settings_manager.cpp \
 		jni/src/unittest/test_mapnode.cpp         \
 		jni/src/unittest/test_nodedef.cpp         \
 		jni/src/unittest/test_noderesolver.cpp    \

doc/lua_api.txt

@@ -2089,7 +2089,9 @@ and `minetest.auth_reload` call the authetification handler.
       given biome_name string.
 * `minetest.get_mapgen_params()` Returns mapgen parameters, a table containing
   `mgname`, `seed`, `chunksize`, `water_level`, and `flags`.
+  * Deprecated: use minetest.get_mapgen_setting(name) instead
 * `minetest.set_mapgen_params(MapgenParams)`
+    * Deprecated: use minetest.set_mapgen_setting(name, value, override) instead
     * Set map generation parameters
     * Function cannot be called after the registration period; only initialization
       and `on_mapgen_init`
@@ -2099,6 +2101,23 @@ and `minetest.auth_reload` call the authetification handler.
         * `flags` contains a comma-delimited string of flags to set,
           or if the prefix `"no"` is attached, clears instead.
         * `flags` is in the same format and has the same options as `mg_flags` in `minetest.conf`
+* `minetest.get_mapgen_setting(name)`
+    * Gets the *active* mapgen setting (or nil if none exists) in string format with the following
+      order of precedence:
+        1) Settings loaded from map_meta.txt or overrides set during mod execution
+        2) Settings set by mods without a metafile override
+        3) Settings explicitly set in the user config file, minetest.conf
+        4) Settings set as the user config default
+* `minetest.get_mapgen_setting_noiseparams(name)`
+    * Same as above, but returns the value as a NoiseParams table if the setting `name` exists
+      and is a valid NoiseParams
+* `minetest.set_mapgen_setting(name, value, [override_meta=false])`
+   * Sets a mapgen param to `value`, and will take effect if the corresponding mapgen setting
+     is not already present in map_meta.txt.  If the optional boolean override_meta is set to true,
+     this setting will become the active setting regardless of the map metafile contents.
+   * Note: to set the seed, use "seed", not "fixed_map_seed"
+* `minetest.set_mapgen_setting_noiseparams(name, value, [override_meta=false])`
+   * Same as above, except value is a NoiseParams table
 * `minetest.set_noiseparams(name, noiseparams, set_default)`
     * Sets the noiseparams setting of `name` to the noiseparams table specified in `noiseparams`.
     * `set_default` is an optional boolean (default: `true`) that specifies whether the setting

src/CMakeLists.txt

@@ -414,6 +414,7 @@ set(common_SRCS
 	light.cpp
 	log.cpp
 	map.cpp
+	map_settings_manager.cpp
 	mapblock.cpp
 	mapgen.cpp
 	mapgen_flat.cpp

src/emerge.cpp

@@ -156,37 +156,19 @@ EmergeManager::~EmergeManager()
 }
 
 
-void EmergeManager::loadMapgenParams()
-{
-	params.load(*g_settings);
-}
-
-
-void EmergeManager::initMapgens()
+bool EmergeManager::initMapgens(MapgenParams *params)
 {
 	if (m_mapgens.size())
-		return;
-
-	MapgenType mgtype = Mapgen::getMapgenType(params.mg_name);
-	if (mgtype == MAPGEN_INVALID) {
-		const char *default_mapgen_name = Mapgen::getMapgenName(MAPGEN_DEFAULT);
-		errorstream << "EmergeManager: mapgen " << params.mg_name <<
-			" not registered; falling back to " <<
-			default_mapgen_name << std::endl;
-
-		params.mg_name = default_mapgen_name;
-		mgtype = MAPGEN_DEFAULT;
-	}
+		return false;
 
-	if (!params.sparams) {
-		params.sparams = Mapgen::createMapgenParams(mgtype);
-		params.sparams->readParams(g_settings);
-	}
+	this->mgparams = params;
 
 	for (u32 i = 0; i != m_threads.size(); i++) {
-		Mapgen *mg = Mapgen::createMapgen(mgtype, i, &params, this);
+		Mapgen *mg = Mapgen::createMapgen(params->mgtype, i, params, this);
 		m_mapgens.push_back(mg);
 	}
+
+	return true;
 }
 
 
@@ -288,12 +270,14 @@ bool EmergeManager::enqueueBlockEmergeEx(
 // Mapgen-related helper functions
 //
 
+
+// TODO(hmmmm): Move this to ServerMap
 v3s16 EmergeManager::getContainingChunk(v3s16 blockpos)
 {
-	return getContainingChunk(blockpos, params.chunksize);
+	return getContainingChunk(blockpos, mgparams->chunksize);
 }
 
-
+// TODO(hmmmm): Move this to ServerMap
 v3s16 EmergeManager::getContainingChunk(v3s16 blockpos, s16 chunksize)
 {
 	s16 coff = -chunksize / 2;
@@ -327,7 +311,7 @@ int EmergeManager::getGroundLevelAtPoint(v2s16 p)
 	return m_mapgens[0]->getGroundLevelAtPoint(p);
 }
 
-
+// TODO(hmmmm): Move this to ServerMap
 bool EmergeManager::isBlockUnderground(v3s16 blockpos)
 {
 #if 0
@@ -338,7 +322,7 @@ bool EmergeManager::isBlockUnderground(v3s16 blockpos)
 #endif
 
 	// Use a simple heuristic; the above method is wildly inaccurate anyway.
-	return blockpos.Y * (MAP_BLOCKSIZE + 1) <= params.water_level;
+	return blockpos.Y * (MAP_BLOCKSIZE + 1) <= mgparams->water_level;
 }
 
 bool EmergeManager::pushBlockEmergeData(

src/emerge.h

@@ -97,8 +97,16 @@ class EmergeManager {
 	u32 gen_notify_on;
 	std::set<u32> gen_notify_on_deco_ids;
 
-	// Map generation parameters
-	MapgenParams params;
+	// Parameters passed to mapgens owned by ServerMap
+	// TODO(hmmmm): Remove this after mapgen helper methods using them
+	// are moved to ServerMap
+	MapgenParams *mgparams;
+
+	// Hackish workaround:
+	// For now, EmergeManager must hold onto a ptr to the Map's setting manager
+	// since the Map can only be accessed through the Environment, and the
+	// Environment is not created until after script initialization.
+	MapSettingsManager *map_settings_mgr;
 
 	// Managers of various map generation-related components
 	BiomeManager *biomemgr;
@@ -110,8 +118,7 @@ class EmergeManager {
 	EmergeManager(IGameDef *gamedef);
 	~EmergeManager();
 
-	void loadMapgenParams();
-	void initMapgens();
+	bool initMapgens(MapgenParams *mgparams);
 
 	void startThreads();
 	void stopThreads();

src/map.cpp

@@ -2130,11 +2130,15 @@ void Map::removeNodeTimer(v3s16 p)
 */
 ServerMap::ServerMap(std::string savedir, IGameDef *gamedef, EmergeManager *emerge):
 	Map(dout_server, gamedef),
+	settings_mgr(g_settings, savedir + DIR_DELIM + "map_meta.txt"),
 	m_emerge(emerge),
 	m_map_metadata_changed(true)
 {
 	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.
 	*/
@@ -2170,26 +2174,15 @@ ServerMap::ServerMap(std::string savedir, IGameDef *gamedef, EmergeManager *emer
 			}
 			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){
-					warningstream<<"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
@@ -2259,19 +2252,26 @@ 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::initBlockMake(v3s16 blockpos, BlockMakeData *data)
 {
-	s16 csize = m_emerge->params.chunksize;
+	s16 csize = getMapgenParams()->chunksize;
 	v3s16 bpmin = EmergeManager::getContainingChunk(blockpos, csize);
 	v3s16 bpmax = bpmin + v3s16(1, 1, 1) * (csize - 1);
 
@@ -2287,7 +2287,7 @@ bool ServerMap::initBlockMake(v3s16 blockpos, BlockMakeData *data)
 		blockpos_over_limit(full_bpmax))
 		return false;
 
-	data->seed = m_emerge->params.seed;
+	data->seed = getSeed();
 	data->blockpos_min = bpmin;
 	data->blockpos_max = bpmax;
 	data->blockpos_requested = blockpos;
@@ -2905,8 +2905,9 @@ 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
@@ -3005,55 +3006,6 @@ void ServerMap::listAllLoadedBlocks(std::vector<v3s16> &dst)
 	}
 }
 
-void ServerMap::saveMapMeta()
-{
-	DSTACK(FUNCTION_NAME);
-
-	createDirs(m_savedir);
-
-	std::string fullpath = m_savedir + DIR_DELIM + "map_meta.txt";
-	std::ostringstream oss(std::ios_base::binary);
-	Settings conf;
-
-	m_emerge->params.save(conf);
-	conf.writeLines(oss);
-
-	oss << "[end_of_params]\n";
-
-	if(!fs::safeWriteToFile(fullpath, oss.str())) {
-		errorstream << "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);
-
-	Settings conf;
-	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");
-	}
-
-	if (!conf.parseConfigLines(is, "[end_of_params]")) {
-		throw SerializationError("ServerMap::loadMapMeta(): "
-				"[end_of_params] not found!");
-	}
-
-	m_emerge->params.load(conf);
-
-	verbosestream << "ServerMap::loadMapMeta(): seed="
-		<< m_emerge->params.seed << std::endl;
-}
-
 void ServerMap::saveSectorMeta(ServerMapSector *sector)
 {
 	DSTACK(FUNCTION_NAME);

src/map.h

@@ -33,6 +33,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "modifiedstate.h"
 #include "util/container.h"
 #include "nodetimer.h"
+#include "map_settings_manager.h"
 
 class Settings;
 class Database;
@@ -46,8 +47,6 @@ class IRollbackManager;
 class EmergeManager;
 class ServerEnvironment;
 struct BlockMakeData;
-struct MapgenParams;
-
 
 /*
 	MapEditEvent
@@ -463,9 +462,8 @@ class ServerMap : public Map
 	void save(ModifiedState save_level);
 	void listAllLoadableBlocks(std::vector<v3s16> &dst);
 	void listAllLoadedBlocks(std::vector<v3s16> &dst);
-	// Saves map seed and possibly other stuff
-	void saveMapMeta();
-	void loadMapMeta();
+
+	MapgenParams *getMapgenParams();
 
 	/*void saveChunkMeta();
 	void loadChunkMeta();*/
@@ -506,6 +504,8 @@ class ServerMap : public Map
 	u64 getSeed();
 	s16 getWaterLevel();
 
+	MapSettingsManager settings_mgr;
+
 private:
 	// Emerge manager
 	EmergeManager *m_emerge;