Initial commit

src/content/CMakeLists.txt

@@ -0,0 +1,7 @@
+set(content_SRCS
+	${CMAKE_CURRENT_SOURCE_DIR}/content.cpp
+	${CMAKE_CURRENT_SOURCE_DIR}/mod_configuration.cpp
+	${CMAKE_CURRENT_SOURCE_DIR}/mods.cpp
+	${CMAKE_CURRENT_SOURCE_DIR}/subgames.cpp
+	PARENT_SCOPE
+)

src/content/content.cpp

@@ -0,0 +1,122 @@
+/*
+Minetest
+Copyright (C) 2018 rubenwardy <rw@rubenwardy.com>
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation; either version 2.1 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License along
+with this program; if not, write to the Free Software Foundation, Inc.,
+51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+
+#include <fstream>
+#include "content/content.h"
+#include "content/subgames.h"
+#include "content/mods.h"
+#include "filesys.h"
+#include "settings.h"
+
+enum ContentType
+{
+	ECT_UNKNOWN,
+	ECT_MOD,
+	ECT_MODPACK,
+	ECT_GAME,
+	ECT_TXP
+};
+
+ContentType getContentType(const ContentSpec &spec)
+{
+	std::ifstream modpack_is((spec.path + DIR_DELIM + "modpack.txt").c_str());
+	if (modpack_is.good()) {
+		modpack_is.close();
+		return ECT_MODPACK;
+	}
+
+	std::ifstream modpack2_is((spec.path + DIR_DELIM + "modpack.conf").c_str());
+	if (modpack2_is.good()) {
+		modpack2_is.close();
+		return ECT_MODPACK;
+	}
+
+	std::ifstream init_is((spec.path + DIR_DELIM + "init.lua").c_str());
+	if (init_is.good()) {
+		init_is.close();
+		return ECT_MOD;
+	}
+
+	std::ifstream game_is((spec.path + DIR_DELIM + "game.conf").c_str());
+	if (game_is.good()) {
+		game_is.close();
+		return ECT_GAME;
+	}
+
+	std::ifstream txp_is((spec.path + DIR_DELIM + "texture_pack.conf").c_str());
+	if (txp_is.good()) {
+		txp_is.close();
+		return ECT_TXP;
+	}
+
+	return ECT_UNKNOWN;
+}
+
+void parseContentInfo(ContentSpec &spec)
+{
+	std::string conf_path;
+
+	switch (getContentType(spec)) {
+	case ECT_MOD:
+		spec.type = "mod";
+		conf_path = spec.path + DIR_DELIM + "mod.conf";
+		break;
+	case ECT_MODPACK:
+		spec.type = "modpack";
+		conf_path = spec.path + DIR_DELIM + "modpack.conf";
+		break;
+	case ECT_GAME:
+		spec.type = "game";
+		conf_path = spec.path + DIR_DELIM + "game.conf";
+		break;
+	case ECT_TXP:
+		spec.type = "txp";
+		conf_path = spec.path + DIR_DELIM + "texture_pack.conf";
+		break;
+	default:
+		spec.type = "unknown";
+		break;
+	}
+
+	Settings conf;
+	if (!conf_path.empty() && conf.readConfigFile(conf_path.c_str())) {
+		if (conf.exists("title"))
+			spec.title = conf.get("title");
+		else if (spec.type == "game" && conf.exists("name"))
+			spec.title = conf.get("name");
+
+		if (spec.type != "game" && conf.exists("name"))
+			spec.name = conf.get("name");
+
+		if (conf.exists("description"))
+			spec.desc = conf.get("description");
+
+		if (conf.exists("author"))
+			spec.author = conf.get("author");
+
+		if (conf.exists("release"))
+			spec.release = conf.getS32("release");
+	}
+
+	if (spec.desc.empty()) {
+		std::ifstream is((spec.path + DIR_DELIM + "description.txt").c_str());
+		spec.desc = std::string((std::istreambuf_iterator<char>(is)),
+				std::istreambuf_iterator<char>());
+	}
+}

src/content/content.h

@@ -0,0 +1,42 @@
+/*
+Minetest
+Copyright (C) 2018 rubenwardy <rw@rubenwardy.com>
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation; either version 2.1 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License along
+with this program; if not, write to the Free Software Foundation, Inc.,
+51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+
+#pragma once
+#include "config.h"
+#include "convert_json.h"
+#include "irrlichttypes.h"
+
+struct ContentSpec
+{
+	std::string type;
+	std::string author;
+	u32 release = 0;
+
+	/// Technical name / Id
+	std::string name;
+
+	/// Human-readable title
+	std::string title;
+
+	/// Short description
+	std::string desc;
+	std::string path;
+};
+
+void parseContentInfo(ContentSpec &spec);

src/content/mod_configuration.cpp

@@ -0,0 +1,255 @@
+/*
+Minetest
+Copyright (C) 2013-22 celeron55, Perttu Ahola <celeron55@gmail.com>
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation; either version 2.1 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License along
+with this program; if not, write to the Free Software Foundation, Inc.,
+51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+
+#include "mod_configuration.h"
+#include "log.h"
+#include "settings.h"
+#include "filesys.h"
+
+void ModConfiguration::printUnsatisfiedModsError() const
+{
+	for (const ModSpec &mod : m_unsatisfied_mods) {
+		errorstream << "mod \"" << mod.name
+					<< "\" has unsatisfied dependencies: ";
+		for (const std::string &unsatisfied_depend : mod.unsatisfied_depends)
+			errorstream << " \"" << unsatisfied_depend << "\"";
+		errorstream << std::endl;
+	}
+}
+
+void ModConfiguration::addModsInPath(const std::string &path, const std::string &virtual_path)
+{
+	addMods(flattenMods(getModsInPath(path, virtual_path)));
+}
+
+void ModConfiguration::addMods(const std::vector<ModSpec> &new_mods)
+{
+	// Maintain a map of all existing m_unsatisfied_mods.
+	// Keys are mod names and values are indices into m_unsatisfied_mods.
+	std::map<std::string, u32> existing_mods;
+	for (u32 i = 0; i < m_unsatisfied_mods.size(); ++i) {
+		existing_mods[m_unsatisfied_mods[i].name] = i;
+	}
+
+	// Add new mods
+	for (int want_from_modpack = 1; want_from_modpack >= 0; --want_from_modpack) {
+		// First iteration:
+		// Add all the mods that come from modpacks
+		// Second iteration:
+		// Add all the mods that didn't come from modpacks
+
+		std::set<std::string> seen_this_iteration;
+
+		for (const ModSpec &mod : new_mods) {
+			if (mod.part_of_modpack != (bool)want_from_modpack)
+				continue;
+
+			if (existing_mods.count(mod.name) == 0) {
+				// GOOD CASE: completely new mod.
+				m_unsatisfied_mods.push_back(mod);
+				existing_mods[mod.name] = m_unsatisfied_mods.size() - 1;
+			} else if (seen_this_iteration.count(mod.name) == 0) {
+				// BAD CASE: name conflict in different levels.
+				u32 oldindex = existing_mods[mod.name];
+				const ModSpec &oldmod = m_unsatisfied_mods[oldindex];
+				warningstream << "Mod name conflict detected: \""
+						<< mod.name << "\"" << std::endl
+						<< "Will not load: " << oldmod.path
+						<< std::endl
+						<< "Overridden by: " << mod.path
+						<< std::endl;
+				m_unsatisfied_mods[oldindex] = mod;
+
+				// If there was a "VERY BAD CASE" name conflict
+				// in an earlier level, ignore it.
+				m_name_conflicts.erase(mod.name);
+			} else {
+				// VERY BAD CASE: name conflict in the same level.
+				u32 oldindex = existing_mods[mod.name];
+				const ModSpec &oldmod = m_unsatisfied_mods[oldindex];
+				warningstream << "Mod name conflict detected: \""
+						<< mod.name << "\"" << std::endl
+						<< "Will not load: " << oldmod.path
+						<< std::endl
+						<< "Will not load: " << mod.path
+						<< std::endl;
+				m_unsatisfied_mods[oldindex] = mod;
+				m_name_conflicts.insert(mod.name);
+			}
+
+			seen_this_iteration.insert(mod.name);
+		}
+	}
+}
+
+void ModConfiguration::addGameMods(const SubgameSpec &gamespec)
+{
+	std::string game_virtual_path;
+	game_virtual_path.append("games/").append(gamespec.id).append("/mods");
+	addModsInPath(gamespec.gamemods_path, game_virtual_path);
+}
+
+void ModConfiguration::addModsFromConfig(
+		const std::string &settings_path,
+		const std::unordered_map<std::string, std::string> &modPaths)
+{
+	Settings conf;
+	std::unordered_map<std::string, std::string> load_mod_names;
+
+	conf.readConfigFile(settings_path.c_str());
+	std::vector<std::string> names = conf.getNames();
+	for (const std::string &name : names) {
+		const auto &value = conf.get(name);
+		if (name.compare(0, 9, "load_mod_") == 0 && value != "false" &&
+				value != "nil")
+			load_mod_names[name.substr(9)] = value;
+	}
+
+	// List of enabled non-game non-world mods
+	std::vector<ModSpec> addon_mods;
+
+	// Map of modname to a list candidate mod paths. Used to list
+	// alternatives if a particular mod cannot be found.
+	std::unordered_map<std::string, std::vector<std::string>> candidates;
+
+	/*
+	 * Iterate through all installed mods except game mods and world mods
+	 *
+	 * If the mod is enabled, add it to `addon_mods`. *
+	 *
+	 * Alternative candidates for a modname are stored in `candidates`,
+	 * and used in an error message later.
+	 *
+	 * If not enabled, add `load_mod_modname = false` to world.mt
+	 */
+	for (const auto &modPath : modPaths) {
+		std::vector<ModSpec> addon_mods_in_path = flattenMods(getModsInPath(modPath.second, modPath.first));
+		for (const auto &mod : addon_mods_in_path) {
+			const auto &pair = load_mod_names.find(mod.name);
+			if (pair != load_mod_names.end()) {
+				if (is_yes(pair->second) || pair->second == mod.virtual_path) {
+					addon_mods.push_back(mod);
+				} else {
+					candidates[pair->first].emplace_back(mod.virtual_path);
+				}
+			} else {
+				conf.setBool("load_mod_" + mod.name, false);
+			}
+		}
+	}
+	conf.updateConfigFile(settings_path.c_str());
+
+	addMods(addon_mods);
+
+	// Remove all loaded mods from `load_mod_names`
+	// NB: as deps have not yet been resolved, `m_unsatisfied_mods` will contain all mods.
+	for (const ModSpec &mod : m_unsatisfied_mods)
+		load_mod_names.erase(mod.name);
+
+	// Complain about mods declared to be loaded, but not found
+	if (!load_mod_names.empty()) {
+		errorstream << "The following mods could not be found:";
+		for (const auto &pair : load_mod_names)
+			errorstream << " \"" << pair.first << "\"";
+		errorstream << std::endl;
+
+		for (const auto &pair : load_mod_names) {
+			const auto &candidate = candidates.find(pair.first);
+			if (candidate != candidates.end()) {
+				errorstream << "Unable to load " << pair.first << " as the specified path "
+							<< pair.second << " could not be found. "
+							<< "However, it is available in the following locations:"
+							<< std::endl;
+				for (const auto &path : candidate->second) {
+					errorstream << " - " << path << std::endl;
+				}
+			}
+		}
+	}
+}
+
+void ModConfiguration::checkConflictsAndDeps()
+{
+	// report on name conflicts
+	if (!m_name_conflicts.empty()) {
+		std::string s = "Unresolved name conflicts for mods ";
+
+		bool add_comma = false;
+		for (const auto& it : m_name_conflicts) {
+			if (add_comma)
+				s.append(", ");
+			s.append("\"").append(it).append("\"");
+			add_comma = true;
+		}
+		s.append(".");
+
+		throw ModError(s);
+	}
+
+	// get the mods in order
+	resolveDependencies();
+}
+
+void ModConfiguration::resolveDependencies()
+{
+	// Step 1: Compile a list of the mod names we're working with
+	std::set<std::string> modnames;
+	for (const ModSpec &mod : m_unsatisfied_mods) {
+		modnames.insert(mod.name);
+	}
+
+	// Step 2: get dependencies (including optional dependencies)
+	// of each mod, split mods into satisfied and unsatisfied
+	std::list<ModSpec> satisfied;
+	std::list<ModSpec> unsatisfied;
+	for (ModSpec mod : m_unsatisfied_mods) {
+		mod.unsatisfied_depends = mod.depends;
+		// check which optional dependencies actually exist
+		for (const std::string &optdep : mod.optdepends) {
+			if (modnames.count(optdep) != 0)
+				mod.unsatisfied_depends.insert(optdep);
+		}
+		// if a mod has no depends it is initially satisfied
+		if (mod.unsatisfied_depends.empty())
+			satisfied.push_back(mod);
+		else
+			unsatisfied.push_back(mod);
+	}
+
+	// Step 3: mods without unmet dependencies can be appended to
+	// the sorted list.
+	while (!satisfied.empty()) {
+		ModSpec mod = satisfied.back();
+		m_sorted_mods.push_back(mod);
+		satisfied.pop_back();
+		for (auto it = unsatisfied.begin(); it != unsatisfied.end();) {
+			ModSpec &mod2 = *it;
+			mod2.unsatisfied_depends.erase(mod.name);
+			if (mod2.unsatisfied_depends.empty()) {
+				satisfied.push_back(mod2);
+				it = unsatisfied.erase(it);
+			} else {
+				++it;
+			}
+		}
+	}
+
+	// Step 4: write back list of unsatisfied mods
+	m_unsatisfied_mods.assign(unsatisfied.begin(), unsatisfied.end());
+}

src/content/mod_configuration.h

@@ -0,0 +1,111 @@
+/*
+Minetest
+Copyright (C) 2013-22 celeron55, Perttu Ahola <celeron55@gmail.com>
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation; either version 2.1 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License along
+with this program; if not, write to the Free Software Foundation, Inc.,
+51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+
+#pragma once
+
+#include "mods.h"
+
+
+/**
+ * ModConfiguration is a subset of installed mods. This class
+ * is used to resolve dependencies and return a sorted list of mods.
+ *
+ * This class should not be extended from, but instead used as a
+ * component in other classes.
+ */
+class ModConfiguration
+{
+public:
+	/**
+	 * @returns true if all dependencies are fullfilled.
+	 */
+	inline bool isConsistent() const { return m_unsatisfied_mods.empty(); }
+
+	inline const std::vector<ModSpec> &getUnsatisfiedMods() const
+	{
+		return m_unsatisfied_mods;
+	}
+
+	/**
+	 * List of mods sorted such that they can be loaded in the
+	 * given order with all dependencies being fulfilled.
+	 *
+	 * I.e: every mod in this list has only dependencies on mods which
+	 * appear earlier in the vector.
+	 */
+	const std::vector<ModSpec> &getMods() const { return m_sorted_mods; }
+
+	void printUnsatisfiedModsError() const;
+
+	/**
+	 * Adds all mods in the given path. used for games, modpacks
+	 * and world-specific mods (worldmods-folders)
+	 *
+	 * @param path To search, should be absolute
+	 * @param virtual_path Virtual path for this directory, see comment in ModSpec
+	 */
+	void addModsInPath(const std::string &path, const std::string &virtual_path);
+
+	/**
+	 * Adds all mods in `new_mods`
+	 */
+	void addMods(const std::vector<ModSpec> &new_mods);
+
+	/**
+	 * Adds game mods
+	 */
+	void addGameMods(const SubgameSpec &gamespec);
+
+	/**
+	 * Adds mods specifed by a world.mt config
+	 *
+	 * @param settings_path Path to world.mt
+	 * @param modPaths Map from virtual name to mod path
+	 */
+	void addModsFromConfig(const std::string &settings_path,
+			const std::unordered_map<std::string, std::string> &modPaths);
+
+	/**
+	 * Call this function once all mods have been added
+	 */
+	void checkConflictsAndDeps();
+
+private:
+	std::vector<ModSpec> m_sorted_mods;
+
+	/**
+	 * move mods from m_unsatisfied_mods to m_sorted_mods
+	 * in an order that satisfies dependencies
+	 */
+	void resolveDependencies();
+
+	// mods with unmet dependencies. Before dependencies are resolved,
+	// this is where all mods are stored. Afterwards this contains
+	// only the ones with really unsatisfied dependencies.
+	std::vector<ModSpec> m_unsatisfied_mods;
+
+	// set of mod names for which an unresolved name conflict
+	// exists. A name conflict happens when two or more mods
+	// at the same level have the same name but different paths.
+	// Levels (mods in higher levels override mods in lower levels):
+	// 1. game mod in modpack; 2. game mod;
+	// 3. world mod in modpack; 4. world mod;
+	// 5. addon mod in modpack; 6. addon mod.
+	std::unordered_set<std::string> m_name_conflicts;
+};

src/content/mods.cpp

@@ -0,0 +1,245 @@
+/*
+Minetest
+Copyright (C) 2013 celeron55, Perttu Ahola <celeron55@gmail.com>
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation; either version 2.1 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License along
+with this program; if not, write to the Free Software Foundation, Inc.,
+51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+
+#include <cctype>
+#include <fstream>
+#include <json/json.h>
+#include <algorithm>
+#include "content/mods.h"
+#include "database/database.h"
+#include "filesys.h"
+#include "log.h"
+#include "content/subgames.h"
+#include "settings.h"
+#include "porting.h"
+#include "convert_json.h"
+#include "script/common/c_internal.h"
+
+void ModSpec::checkAndLog() const
+{
+	if (!string_allowed(name, MODNAME_ALLOWED_CHARS)) {
+		throw ModError("Error loading mod \"" + name +
+			"\": Mod name does not follow naming conventions: "
+				"Only characters [a-z0-9_] are allowed.");
+	}
+
+	// Log deprecation messages
+	auto handling_mode = get_deprecated_handling_mode();
+	if (!deprecation_msgs.empty() && handling_mode != DeprecatedHandlingMode::Ignore) {
+		std::ostringstream os;
+		os << "Mod " << name << " at " << path << ":" << std::endl;
+		for (auto msg : deprecation_msgs)
+			os << "\t" << msg << std::endl;
+
+		if (handling_mode == DeprecatedHandlingMode::Error)
+			throw ModError(os.str());
+		else
+			warningstream << os.str();
+	}
+}
+
+bool parseDependsString(std::string &dep, std::unordered_set<char> &symbols)
+{
+	dep = trim(dep);
+	symbols.clear();
+	size_t pos = dep.size();
+	while (pos > 0 &&
+			!string_allowed(dep.substr(pos - 1, 1), MODNAME_ALLOWED_CHARS)) {
+		// last character is a symbol, not part of the modname
+		symbols.insert(dep[pos - 1]);
+		--pos;
+	}
+	dep = trim(dep.substr(0, pos));
+	return !dep.empty();
+}
+
+bool parseModContents(ModSpec &spec)
+{
+	// NOTE: this function works in mutual recursion with getModsInPath
+
+	spec.depends.clear();
+	spec.optdepends.clear();
+	spec.is_modpack = false;
+	spec.modpack_content.clear();
+
+	// Handle modpacks (defined by containing modpack.txt)
+	if (fs::IsFile(spec.path + DIR_DELIM + "modpack.txt") ||
+			fs::IsFile(spec.path + DIR_DELIM + "modpack.conf")) {
+		spec.is_modpack = true;
+		spec.modpack_content = getModsInPath(spec.path, spec.virtual_path, true);
+		return true;
+	} else if (!fs::IsFile(spec.path + DIR_DELIM + "init.lua")) {
+		return false;
+	}
+
+
+	Settings info;
+	info.readConfigFile((spec.path + DIR_DELIM + "mod.conf").c_str());
+
+	if (info.exists("name"))
+		spec.name = info.get("name");
+	else
+		spec.deprecation_msgs.push_back("Mods not having a mod.conf file with the name is deprecated.");
+
+	if (info.exists("author"))
+		spec.author = info.get("author");
+
+	if (info.exists("release"))
+		spec.release = info.getS32("release");
+
+	// Attempt to load dependencies from mod.conf
+	bool mod_conf_has_depends = false;
+	if (info.exists("depends")) {
+		mod_conf_has_depends = true;
+		std::string dep = info.get("depends");
+		// clang-format off
+		dep.erase(std::remove_if(dep.begin(), dep.end(),
+				static_cast<int (*)(int)>(&std::isspace)), dep.end());
+		// clang-format on
+		for (const auto &dependency : str_split(dep, ',')) {
+			spec.depends.insert(dependency);
+		}
+	}
+
+	if (info.exists("optional_depends")) {
+		mod_conf_has_depends = true;
+		std::string dep = info.get("optional_depends");
+		// clang-format off
+		dep.erase(std::remove_if(dep.begin(), dep.end(),
+				static_cast<int (*)(int)>(&std::isspace)), dep.end());
+		// clang-format on
+		for (const auto &dependency : str_split(dep, ',')) {
+			spec.optdepends.insert(dependency);
+		}
+	}
+
+	// Fallback to depends.txt
+	if (!mod_conf_has_depends) {
+		std::vector<std::string> dependencies;
+
+		std::ifstream is((spec.path + DIR_DELIM + "depends.txt").c_str());
+
+		if (is.good())
+			spec.deprecation_msgs.push_back("depends.txt is deprecated, please use mod.conf instead.");
+
+		while (is.good()) {
+			std::string dep;
+			std::getline(is, dep);
+			dependencies.push_back(dep);
+		}
+
+		for (auto &dependency : dependencies) {
+			std::unordered_set<char> symbols;
+			if (parseDependsString(dependency, symbols)) {
+				if (symbols.count('?') != 0) {
+					spec.optdepends.insert(dependency);
+				} else {
+					spec.depends.insert(dependency);
+				}
+			}
+		}
+	}
+
+	if (info.exists("description"))
+		spec.desc = info.get("description");
+	else if (fs::ReadFile(spec.path + DIR_DELIM + "description.txt", spec.desc))
+		spec.deprecation_msgs.push_back("description.txt is deprecated, please use mod.conf instead.");
+
+	return true;
+}
+
+std::map<std::string, ModSpec> getModsInPath(
+		const std::string &path, const std::string &virtual_path, bool part_of_modpack)
+{
+	// NOTE: this function works in mutual recursion with parseModContents
+
+	std::map<std::string, ModSpec> result;
+	std::vector<fs::DirListNode> dirlist = fs::GetDirListing(path);
+	std::string mod_path;
+	std::string mod_virtual_path;
+
+	for (const fs::DirListNode &dln : dirlist) {
+		if (!dln.dir)
+			continue;
+
+		const std::string &modname = dln.name;
+		// Ignore all directories beginning with a ".", especially
+		// VCS directories like ".git" or ".svn"
+		if (modname[0] == '.')
+			continue;
+
+		mod_path.clear();
+		mod_path.append(path).append(DIR_DELIM).append(modname);
+
+		mod_virtual_path.clear();
+		// Intentionally uses / to keep paths same on different platforms
+		mod_virtual_path.append(virtual_path).append("/").append(modname);
+
+		ModSpec spec(modname, mod_path, part_of_modpack, mod_virtual_path);
+		parseModContents(spec);
+		result.insert(std::make_pair(modname, spec));
+	}
+	return result;
+}
+
+std::vector<ModSpec> flattenMods(const std::map<std::string, ModSpec> &mods)
+{
+	std::vector<ModSpec> result;
+	for (const auto &it : mods) {
+		const ModSpec &mod = it.second;
+		if (mod.is_modpack) {
+			std::vector<ModSpec> content = flattenMods(mod.modpack_content);
+			result.reserve(result.size() + content.size());
+			result.insert(result.end(), content.begin(), content.end());
+
+		} else // not a modpack
+		{
+			result.push_back(mod);
+		}
+	}
+	return result;
+}
+
+
+ModMetadata::ModMetadata(const std::string &mod_name, ModMetadataDatabase *database):
+	m_mod_name(mod_name), m_database(database)
+{
+	m_database->getModEntries(m_mod_name, &m_stringvars);
+}
+
+void ModMetadata::clear()
+{
+	for (const auto &pair : m_stringvars) {
+		m_database->removeModEntry(m_mod_name, pair.first);
+	}
+	Metadata::clear();
+}
+
+bool ModMetadata::setString(const std::string &name, const std::string &var)
+{
+	if (Metadata::setString(name, var)) {
+		if (var.empty()) {
+			m_database->removeModEntry(m_mod_name, name);
+		} else {
+			m_database->setModEntry(m_mod_name, name, var);
+		}
+		return true;
+	}
+	return false;
+}

src/content/mods.h

@@ -0,0 +1,129 @@
+/*
+Minetest
+Copyright (C) 2013 celeron55, Perttu Ahola <celeron55@gmail.com>
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation; either version 2.1 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License along
+with this program; if not, write to the Free Software Foundation, Inc.,
+51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+
+#pragma once
+
+#include "irrlichttypes.h"
+#include <list>
+#include <set>
+#include <vector>
+#include <string>
+#include <map>
+#include <json/json.h>
+#include <unordered_set>
+#include "util/basic_macros.h"
+#include "config.h"
+#include "metadata.h"
+#include "subgames.h"
+
+class ModMetadataDatabase;
+
+#define MODNAME_ALLOWED_CHARS "abcdefghijklmnopqrstuvwxyz0123456789_"
+
+struct ModSpec
+{
+	std::string name;
+	std::string author;
+	std::string path;
+	std::string desc;
+	int release = 0;
+
+	// if normal mod:
+	std::unordered_set<std::string> depends;
+	std::unordered_set<std::string> optdepends;
+	std::unordered_set<std::string> unsatisfied_depends;
+
+	bool part_of_modpack = false;
+	bool is_modpack = false;
+
+	/**
+	 * A constructed canonical path to represent this mod's location.
+	 * This intended to be used as an identifier for a modpath that tolerates file movement,
+	 * and cannot be used to read the mod files.
+	 *
+	 * Note that `mymod` is the directory name, not the mod name specified in mod.conf.
+	 *
+	 * Ex:
+	 *
+	 * - mods/mymod
+	 * - mods/mymod (1)
+	 *     (^ this would have name=mymod in mod.conf)
+	 * - mods/modpack1/mymod
+	 * - games/mygame/mods/mymod
+	 * - worldmods/mymod
+	 */
+	std::string virtual_path;
+
+	// For logging purposes
+	std::vector<const char *> deprecation_msgs;
+
+	// if modpack:
+	std::map<std::string, ModSpec> modpack_content;
+
+	ModSpec()
+	{
+	}
+
+	ModSpec(const std::string &name, const std::string &path, bool part_of_modpack, const std::string &virtual_path) :
+			name(name), path(path), part_of_modpack(part_of_modpack), virtual_path(virtual_path)
+	{
+	}
+
+	void checkAndLog() const;
+};
+
+/**
+ * Retrieves depends, optdepends, is_modpack and modpack_content
+ *
+ * @returns false if not a mod
+ */
+bool parseModContents(ModSpec &mod);
+
+/**
+ * Gets a list of all mods and modpacks in path
+ *
+ * @param Path to search, should be absolute
+ * @param part_of_modpack Is this searching within a modpack?
+ * @param virtual_path Virtual path for this directory, see comment in ModSpec
+ * @returns map of mods
+ */
+std::map<std::string, ModSpec> getModsInPath(const std::string &path,
+		const std::string &virtual_path, bool part_of_modpack = false);
+
+// replaces modpack Modspecs with their content
+std::vector<ModSpec> flattenMods(const std::map<std::string, ModSpec> &mods);
+
+
+class ModMetadata : public Metadata
+{
+public:
+	ModMetadata() = delete;
+	ModMetadata(const std::string &mod_name, ModMetadataDatabase *database);
+	~ModMetadata() = default;
+
+	virtual void clear();
+
+	const std::string &getModName() const { return m_mod_name; }
+
+	virtual bool setString(const std::string &name, const std::string &var);
+
+private:
+	std::string m_mod_name;
+	ModMetadataDatabase *m_database;
+};

src/content/subgames.cpp

@@ -0,0 +1,423 @@
+/*
+Minetest
+Copyright (C) 2013 celeron55, Perttu Ahola <celeron55@gmail.com>
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation; either version 2.1 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License along
+with this program; if not, write to the Free Software Foundation, Inc.,
+51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+
+#include <common/c_internal.h>
+#include "content/subgames.h"
+#include "porting.h"
+#include "filesys.h"
+#include "settings.h"
+#include "log.h"
+#include "util/strfnd.h"
+#include "defaultsettings.h" // for set_default_settings
+#include "map_settings_manager.h"
+#include "util/string.h"
+
+#ifndef SERVER
+#include "client/tile.h" // getImagePath
+#endif
+
+// The maximum number of identical world names allowed
+#define MAX_WORLD_NAMES 100
+
+namespace
+{
+
+bool getGameMinetestConfig(const std::string &game_path, Settings &conf)
+{
+	std::string conf_path = game_path + DIR_DELIM + "minetest.conf";
+	return conf.readConfigFile(conf_path.c_str());
+}
+
+}
+
+
+void SubgameSpec::checkAndLog() const
+{
+	// Log deprecation messages
+	auto handling_mode = get_deprecated_handling_mode();
+	if (!deprecation_msgs.empty() && handling_mode != DeprecatedHandlingMode::Ignore) {
+		std::ostringstream os;
+		os << "Game " << title << " at " << path << ":" << std::endl;
+		for (auto msg : deprecation_msgs)
+			os << "\t" << msg << std::endl;
+
+		if (handling_mode == DeprecatedHandlingMode::Error)
+			throw ModError(os.str());
+		else
+			warningstream << os.str();
+	}
+}
+
+
+struct GameFindPath
+{
+	std::string path;
+	bool user_specific;
+	GameFindPath(const std::string &path, bool user_specific) :
+			path(path), user_specific(user_specific)
+	{
+	}
+};
+
+std::string getSubgamePathEnv()
+{
+	char *subgame_path = getenv("MINETEST_SUBGAME_PATH");
+	return subgame_path ? std::string(subgame_path) : "";
+}
+
+SubgameSpec findSubgame(const std::string &id)
+{
+	if (id.empty())
+		return SubgameSpec();
+	std::string share = porting::path_share;
+	std::string user = porting::path_user;
+
+	// Get games install locations
+	Strfnd search_paths(getSubgamePathEnv());
+
+	// Get all possible paths fo game
+	std::vector<GameFindPath> find_paths;
+	while (!search_paths.at_end()) {
+		std::string path = search_paths.next(PATH_DELIM);
+		path.append(DIR_DELIM).append(id);
+		find_paths.emplace_back(path, false);
+		path.append("_game");
+		find_paths.emplace_back(path, false);
+	}
+
+	std::string game_base = DIR_DELIM;
+	game_base = game_base.append("games").append(DIR_DELIM).append(id);
+	std::string game_suffixed = game_base + "_game";
+	find_paths.emplace_back(user + game_suffixed, true);
+	find_paths.emplace_back(user + game_base, true);
+	find_paths.emplace_back(share + game_suffixed, false);
+	find_paths.emplace_back(share + game_base, false);
+
+	// Find game directory
+	std::string game_path;
+	bool user_game = true; // Game is in user's directory
+	for (const GameFindPath &find_path : find_paths) {
+		const std::string &try_path = find_path.path;
+		if (fs::PathExists(try_path)) {
+			game_path = try_path;
+			user_game = find_path.user_specific;
+			break;
+		}
+	}
+
+	if (game_path.empty())
+		return SubgameSpec();
+
+	std::string gamemod_path = game_path + DIR_DELIM + "mods";
+
+	// Find mod directories
+	std::unordered_map<std::string, std::string> mods_paths;
+	mods_paths["mods"] = user + DIR_DELIM + "mods";
+	if (!user_game && user != share)
+		mods_paths["share"] = share + DIR_DELIM + "mods";
+
+	for (const std::string &mod_path : getEnvModPaths()) {
+		mods_paths[fs::AbsolutePath(mod_path)] = mod_path;
+	}
+
+	// Get meta
+	std::string conf_path = game_path + DIR_DELIM + "game.conf";
+	Settings conf;
+	conf.readConfigFile(conf_path.c_str());
+
+	std::string game_title;
+	if (conf.exists("title"))
+		game_title = conf.get("title");
+	else if (conf.exists("name"))
+		game_title = conf.get("name");
+	else
+		game_title = id;
+
+	std::string game_author;
+	if (conf.exists("author"))
+		game_author = conf.get("author");
+
+	int game_release = 0;
+	if (conf.exists("release"))
+		game_release = conf.getS32("release");
+
+	std::string menuicon_path;
+#ifndef SERVER
+	menuicon_path = getImagePath(
+			game_path + DIR_DELIM + "menu" + DIR_DELIM + "icon.png");
+#endif
+
+	SubgameSpec spec(id, game_path, gamemod_path, mods_paths, game_title,
+			menuicon_path, game_author, game_release);
+
+	if (conf.exists("name") && !conf.exists("title"))
+		spec.deprecation_msgs.push_back("\"name\" setting in game.conf is deprecated, please use \"title\" instead");
+
+	return spec;
+}
+
+SubgameSpec findWorldSubgame(const std::string &world_path)
+{
+	std::string world_gameid = getWorldGameId(world_path, true);
+	// See if world contains an embedded game; if so, use it.
+	std::string world_gamepath = world_path + DIR_DELIM + "game";
+	if (fs::PathExists(world_gamepath)) {
+		SubgameSpec gamespec;
+		gamespec.id = world_gameid;
+		gamespec.path = world_gamepath;
+		gamespec.gamemods_path = world_gamepath + DIR_DELIM + "mods";
+
+		Settings conf;
+		std::string conf_path = world_gamepath + DIR_DELIM + "game.conf";
+		conf.readConfigFile(conf_path.c_str());
+
+		if (conf.exists("title"))
+			gamespec.title = conf.get("title");
+		else if (conf.exists("name"))
+			gamespec.title = conf.get("name");
+		else
+			gamespec.title = world_gameid;
+
+		return gamespec;
+	}
+	return findSubgame(world_gameid);
+}
+
+std::set<std::string> getAvailableGameIds()
+{
+	std::set<std::string> gameids;
+	std::set<std::string> gamespaths;
+	gamespaths.insert(porting::path_share + DIR_DELIM + "games");
+	gamespaths.insert(porting::path_user + DIR_DELIM + "games");
+
+	Strfnd search_paths(getSubgamePathEnv());
+
+	while (!search_paths.at_end())
+		gamespaths.insert(search_paths.next(PATH_DELIM));
+
+	for (const std::string &gamespath : gamespaths) {
+		std::vector<fs::DirListNode> dirlist = fs::GetDirListing(gamespath);
+		for (const fs::DirListNode &dln : dirlist) {
+			if (!dln.dir)
+				continue;
+
+			// If configuration file is not found or broken, ignore game
+			Settings conf;
+			std::string conf_path = gamespath + DIR_DELIM + dln.name +
+						DIR_DELIM + "game.conf";
+			if (!conf.readConfigFile(conf_path.c_str()))
+				continue;
+
+			// Add it to result
+			const char *ends[] = {"_game", NULL};
+			std::string shorter = removeStringEnd(dln.name, ends);
+			if (!shorter.empty())
+				gameids.insert(shorter);
+			else
+				gameids.insert(dln.name);
+		}
+	}
+	return gameids;
+}
+
+std::vector<SubgameSpec> getAvailableGames()
+{
+	std::vector<SubgameSpec> specs;
+	std::set<std::string> gameids = getAvailableGameIds();
+	specs.reserve(gameids.size());
+	for (const auto &gameid : gameids)
+		specs.push_back(findSubgame(gameid));
+	return specs;
+}
+
+#define LEGACY_GAMEID "minetest"
+
+bool getWorldExists(const std::string &world_path)
+{
+	return (fs::PathExists(world_path + DIR_DELIM + "map_meta.txt") ||
+			fs::PathExists(world_path + DIR_DELIM + "world.mt"));
+}
+
+//! Try to get the displayed name of a world
+std::string getWorldName(const std::string &world_path, const std::string &default_name)
+{
+	std::string conf_path = world_path + DIR_DELIM + "world.mt";
+	Settings conf;
+	bool succeeded = conf.readConfigFile(conf_path.c_str());
+	if (!succeeded) {
+		return default_name;
+	}
+
+	if (!conf.exists("world_name"))
+		return default_name;
+	return conf.get("world_name");
+}
+
+std::string getWorldGameId(const std::string &world_path, bool can_be_legacy)
+{
+	std::string conf_path = world_path + DIR_DELIM + "world.mt";
+	Settings conf;
+	bool succeeded = conf.readConfigFile(conf_path.c_str());
+	if (!succeeded) {
+		if (can_be_legacy) {
+			// If map_meta.txt exists, it is probably an old minetest world
+			if (fs::PathExists(world_path + DIR_DELIM + "map_meta.txt"))
+				return LEGACY_GAMEID;
+		}
+		return "";
+	}
+	if (!conf.exists("gameid"))
+		return "";
+	// The "mesetint" gameid has been discarded
+	if (conf.get("gameid") == "mesetint")
+		return "minetest";
+	return conf.get("gameid");
+}
+
+std::string getWorldPathEnv()
+{
+	char *world_path = getenv("MINETEST_WORLD_PATH");
+	return world_path ? std::string(world_path) : "";
+}
+
+std::vector<WorldSpec> getAvailableWorlds()
+{
+	std::vector<WorldSpec> worlds;
+	std::set<std::string> worldspaths;
+
+	Strfnd search_paths(getWorldPathEnv());
+
+	while (!search_paths.at_end())
+		worldspaths.insert(search_paths.next(PATH_DELIM));
+
+	worldspaths.insert(porting::path_user + DIR_DELIM + "worlds");
+	infostream << "Searching worlds..." << std::endl;
+	for (const std::string &worldspath : worldspaths) {
+		infostream << "  In " << worldspath << ": ";
+		std::vector<fs::DirListNode> dirvector = fs::GetDirListing(worldspath);
+		for (const fs::DirListNode &dln : dirvector) {
+			if (!dln.dir)
+				continue;
+			std::string fullpath = worldspath + DIR_DELIM + dln.name;
+			std::string name = getWorldName(fullpath, dln.name);
+			// Just allow filling in the gameid always for now
+			bool can_be_legacy = true;
+			std::string gameid = getWorldGameId(fullpath, can_be_legacy);
+			WorldSpec spec(fullpath, name, gameid);
+			if (!spec.isValid()) {
+				infostream << "(invalid: " << name << ") ";
+			} else {
+				infostream << name << " ";
+				worlds.push_back(spec);
+			}
+		}
+		infostream << std::endl;
+	}
+	// Check old world location
+	do {
+		std::string fullpath = porting::path_user + DIR_DELIM + "world";
+		if (!fs::PathExists(fullpath))
+			break;
+		std::string name = "Old World";
+		std::string gameid = getWorldGameId(fullpath, true);
+		WorldSpec spec(fullpath, name, gameid);
+		infostream << "Old world found." << std::endl;
+		worlds.push_back(spec);
+	} while (false);
+	infostream << worlds.size() << " found." << std::endl;
+	return worlds;
+}
+
+void loadGameConfAndInitWorld(const std::string &path, const std::string &name,
+		const SubgameSpec &gamespec, bool create_world)
+{
+	std::string final_path = path;
+
+	// If we're creating a new world, ensure that the path isn't already taken
+	if (create_world) {
+		int counter = 1;
+		while (fs::PathExists(final_path) && counter < MAX_WORLD_NAMES) {
+			final_path = path + "_" + std::to_string(counter);
+			counter++;
+		}
+
+		if (fs::PathExists(final_path)) {
+			throw BaseException("Too many similar filenames");
+		}
+	}
+
+	Settings *game_settings = Settings::getLayer(SL_GAME);
+	const bool new_game_settings = (game_settings == nullptr);
+	if (new_game_settings) {
+		// Called by main-menu without a Server instance running
+		// -> create and free manually
+		game_settings = Settings::createLayer(SL_GAME);
+	}
+
+	getGameMinetestConfig(gamespec.path, *game_settings);
+	game_settings->removeSecureSettings();
+
+	infostream << "Initializing world at " << final_path << std::endl;
+
+	fs::CreateAllDirs(final_path);
+
+	// Create world.mt if does not already exist
+	std::string worldmt_path = final_path + DIR_DELIM "world.mt";
+	if (!fs::PathExists(worldmt_path)) {
+		Settings conf;
+
+		conf.set("world_name", name);
+		conf.set("gameid", gamespec.id);
+		conf.set("backend", "sqlite3");
+		conf.set("player_backend", "sqlite3");
+		conf.set("auth_backend", "sqlite3");
+		conf.set("mod_storage_backend", "sqlite3");
+		conf.setBool("creative_mode", g_settings->getBool("creative_mode"));
+		conf.setBool("enable_damage", g_settings->getBool("enable_damage"));
+
+		if (!conf.updateConfigFile(worldmt_path.c_str())) {
+			throw BaseException("Failed to update the config file");
+		}
+	}
+
+	// Create map_meta.txt if does not already exist
+	std::string map_meta_path = final_path + DIR_DELIM + "map_meta.txt";
+	if (!fs::PathExists(map_meta_path)) {
+		MapSettingsManager mgr(map_meta_path);
+
+		mgr.setMapSetting("seed", g_settings->get("fixed_map_seed"));
+
+		mgr.makeMapgenParams();
+		mgr.saveMapMeta();
+	}
+
+	// The Settings object is no longer needed for created worlds
+	if (new_game_settings)
+		delete game_settings;
+}
+
+std::vector<std::string> getEnvModPaths()
+{
+	const char *c_mod_path = getenv("MINETEST_MOD_PATH");
+	std::vector<std::string> paths;
+	Strfnd search_paths(c_mod_path ? c_mod_path : "");
+	while (!search_paths.at_end())
+		paths.push_back(search_paths.next(PATH_DELIM));
+	return paths;
+}

src/content/subgames.h

@@ -0,0 +1,101 @@
+/*
+Minetest
+Copyright (C) 2013 celeron55, Perttu Ahola <celeron55@gmail.com>
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation; either version 2.1 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License along
+with this program; if not, write to the Free Software Foundation, Inc.,
+51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+
+#pragma once
+
+#include <string>
+#include <set>
+#include <unordered_map>
+#include <vector>
+
+class Settings;
+
+struct SubgameSpec
+{
+	std::string id;
+	std::string title;
+	std::string author;
+	int release;
+	std::string path;
+	std::string gamemods_path;
+
+	/**
+	 * Map from virtual path to mods path
+	 */
+	std::unordered_map<std::string, std::string> addon_mods_paths;
+	std::string menuicon_path;
+
+	// For logging purposes
+	std::vector<const char *> deprecation_msgs;
+
+	SubgameSpec(const std::string &id = "", const std::string &path = "",
+			const std::string &gamemods_path = "",
+			const std::unordered_map<std::string, std::string> &addon_mods_paths = {},
+			const std::string &title = "",
+			const std::string &menuicon_path = "",
+			const std::string &author = "", int release = 0) :
+			id(id),
+			title(title), author(author), release(release), path(path),
+			gamemods_path(gamemods_path), addon_mods_paths(addon_mods_paths),
+			menuicon_path(menuicon_path)
+	{
+	}
+
+	bool isValid() const { return (!id.empty() && !path.empty()); }
+	void checkAndLog() const;
+};
+
+SubgameSpec findSubgame(const std::string &id);
+SubgameSpec findWorldSubgame(const std::string &world_path);
+
+std::set<std::string> getAvailableGameIds();
+std::vector<SubgameSpec> getAvailableGames();
+// Get the list of paths to mods in the environment variable $MINETEST_MOD_PATH
+std::vector<std::string> getEnvModPaths();
+
+bool getWorldExists(const std::string &world_path);
+//! Try to get the displayed name of a world
+std::string getWorldName(const std::string &world_path, const std::string &default_name);
+std::string getWorldGameId(const std::string &world_path, bool can_be_legacy = false);
+
+struct WorldSpec
+{
+	std::string path;
+	std::string name;
+	std::string gameid;
+
+	WorldSpec(const std::string &path = "", const std::string &name = "",
+			const std::string &gameid = "") :
+			path(path),
+			name(name), gameid(gameid)
+	{
+	}
+
+	bool isValid() const
+	{
+		return (!name.empty() && !path.empty() && !gameid.empty());
+	}
+};
+
+std::vector<WorldSpec> getAvailableWorlds();
+
+// loads the subgame's config and creates world directory
+// and world.mt if they don't exist
+void loadGameConfAndInitWorld(const std::string &path, const std::string &name,
+		const SubgameSpec &gamespec, bool create_world);