Add online content repository

Replaces mods and texture pack tabs with a single content tab

9 files changed, 1318 insertions, 0 deletions

diff --git a/src/content/CMakeLists.txt b/src/content/CMakeLists.txt
new file mode 100644
index 000000000..5adcf6b1e
--- /dev/null
+++ b/src/content/CMakeLists.txt
@@ -0,0 +1,7 @@
+set(content_SRCS
+	${CMAKE_CURRENT_SOURCE_DIR}/content.cpp
+	${CMAKE_CURRENT_SOURCE_DIR}/packages.cpp
+	${CMAKE_CURRENT_SOURCE_DIR}/mods.cpp
+	${CMAKE_CURRENT_SOURCE_DIR}/subgames.cpp
+	PARENT_SCOPE
+)
diff --git a/src/content/content.cpp b/src/content/content.cpp
new file mode 100644
index 000000000..d45c5feab
--- /dev/null
+++ b/src/content/content.cpp
@@ -0,0 +1,108 @@
+/*
+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 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 + "mod.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("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 (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>());
+	}
+}
diff --git a/src/content/content.h b/src/content/content.h
new file mode 100644
index 000000000..782a4fd7a
--- /dev/null
+++ b/src/content/content.h
@@ -0,0 +1,33 @@
+/*
+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"
+
+struct ContentSpec
+{
+	std::string type;
+	std::string author;
+	std::string name;
+	std::string desc;
+	std::string path;
+};
+
+void parseContentInfo(ContentSpec &spec);
diff --git a/src/content/mods.cpp b/src/content/mods.cpp
new file mode 100644
index 000000000..694bbcca8
--- /dev/null
+++ b/src/content/mods.cpp
@@ -0,0 +1,469 @@
+/*
+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 "filesys.h"
+#include "log.h"
+#include "content/subgames.h"
+#include "settings.h"
+#include "porting.h"
+#include "convert_json.h"
+
+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();
+}
+
+void parseModContents(ModSpec &spec)
+{
+	// NOTE: this function works in mutual recursion with getModsInPath
+	Settings info;
+	info.readConfigFile((spec.path + DIR_DELIM + "mod.conf").c_str());
+
+	if (info.exists("name"))
+		spec.name = info.get("name");
+
+	if (info.exists("author"))
+		spec.author = info.get("author");
+
+	spec.depends.clear();
+	spec.optdepends.clear();
+	spec.is_modpack = false;
+	spec.modpack_content.clear();
+
+	// Handle modpacks (defined by containing modpack.txt)
+	std::ifstream modpack_is((spec.path + DIR_DELIM + "modpack.txt").c_str());
+	if (modpack_is.good()) {    // a modpack, recursively get the mods in it
+		modpack_is.close(); // We don't actually need the file
+		spec.is_modpack = true;
+		spec.modpack_content = getModsInPath(spec.path, true);
+		// modpacks have no dependencies; they are defined and
+		// tracked separately for each mod in the modpack
+
+	} else {
+		// 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());
+			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 {
+			std::ifstream is((spec.path + DIR_DELIM + "description.txt")
+							 .c_str());
+			spec.desc = std::string((std::istreambuf_iterator<char>(is)),
+					std::istreambuf_iterator<char>());
+		}
+	}
+}
+
+std::map<std::string, ModSpec> getModsInPath(
+		const std::string &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 modpath;
+
+	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;
+
+		modpath.clear();
+		modpath.append(path).append(DIR_DELIM).append(modname);
+
+		ModSpec spec(modname, modpath, part_of_modpack);
+		parseModContents(spec);
+		result.insert(std::make_pair(modname, spec));
+	}
+	return result;
+}
+
+std::vector<ModSpec> flattenMods(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;
+}
+
+ModConfiguration::ModConfiguration(const std::string &worldpath)
+{
+}
+
+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)
+{
+	addMods(flattenMods(getModsInPath(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::addModsFromConfig(
+		const std::string &settings_path, const std::set<std::string> &mods)
+{
+	Settings conf;
+	std::set<std::string> load_mod_names;
+
+	conf.readConfigFile(settings_path.c_str());
+	std::vector<std::string> names = conf.getNames();
+	for (const std::string &name : names) {
+		if (name.compare(0, 9, "load_mod_") == 0 && conf.getBool(name))
+			load_mod_names.insert(name.substr(9));
+	}
+
+	std::vector<ModSpec> addon_mods;
+	for (const std::string &i : mods) {
+		std::vector<ModSpec> addon_mods_in_path = flattenMods(getModsInPath(i));
+		for (std::vector<ModSpec>::const_iterator it = addon_mods_in_path.begin();
+				it != addon_mods_in_path.end(); ++it) {
+			const ModSpec &mod = *it;
+			if (load_mod_names.count(mod.name) != 0)
+				addon_mods.push_back(mod);
+			else
+				conf.setBool("load_mod_" + mod.name, false);
+		}
+	}
+	conf.updateConfigFile(settings_path.c_str());
+
+	addMods(addon_mods);
+	checkConflictsAndDeps();
+
+	// complain about mods declared to be loaded, but not found
+	for (const ModSpec &addon_mod : addon_mods)
+		load_mod_names.erase(addon_mod.name);
+
+	std::vector<ModSpec> unsatisfiedMods = getUnsatisfiedMods();
+
+	for (const ModSpec &unsatisfiedMod : unsatisfiedMods)
+		load_mod_names.erase(unsatisfiedMod.name);
+
+	if (!load_mod_names.empty()) {
+		errorstream << "The following mods could not be found:";
+		for (const std::string &mod : load_mod_names)
+			errorstream << " \"" << mod << "\"";
+		errorstream << std::endl;
+	}
+}
+
+void ModConfiguration::checkConflictsAndDeps()
+{
+	// report on name conflicts
+	if (!m_name_conflicts.empty()) {
+		std::string s = "Unresolved name conflicts for mods ";
+		for (std::unordered_set<std::string>::const_iterator it =
+						m_name_conflicts.begin();
+				it != m_name_conflicts.end(); ++it) {
+			if (it != m_name_conflicts.begin())
+				s += ", ";
+			s += std::string("\"") + (*it) + "\"";
+		}
+		s += ".";
+		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());
+}
+
+#ifndef SERVER
+ClientModConfiguration::ClientModConfiguration(const std::string &path) :
+		ModConfiguration(path)
+{
+	std::set<std::string> paths;
+	std::string path_user = porting::path_user + DIR_DELIM + "clientmods";
+	paths.insert(path);
+	paths.insert(path_user);
+
+	std::string settings_path = path_user + DIR_DELIM + "mods.conf";
+	addModsFromConfig(settings_path, paths);
+}
+#endif
+
+ModMetadata::ModMetadata(const std::string &mod_name) : m_mod_name(mod_name)
+{
+}
+
+void ModMetadata::clear()
+{
+	Metadata::clear();
+	m_modified = true;
+}
+
+bool ModMetadata::save(const std::string &root_path)
+{
+	Json::Value json;
+	for (StringMap::const_iterator it = m_stringvars.begin();
+			it != m_stringvars.end(); ++it) {
+		json[it->first] = it->second;
+	}
+
+	if (!fs::PathExists(root_path)) {
+		if (!fs::CreateAllDirs(root_path)) {
+			errorstream << "ModMetadata[" << m_mod_name
+				    << "]: Unable to save. '" << root_path
+				    << "' tree cannot be created." << std::endl;
+			return false;
+		}
+	} else if (!fs::IsDir(root_path)) {
+		errorstream << "ModMetadata[" << m_mod_name << "]: Unable to save. '"
+			    << root_path << "' is not a directory." << std::endl;
+		return false;
+	}
+
+	bool w_ok = fs::safeWriteToFile(
+			root_path + DIR_DELIM + m_mod_name, fastWriteJson(json));
+
+	if (w_ok) {
+		m_modified = false;
+	} else {
+		errorstream << "ModMetadata[" << m_mod_name << "]: failed write file."
+			    << std::endl;
+	}
+	return w_ok;
+}
+
+bool ModMetadata::load(const std::string &root_path)
+{
+	m_stringvars.clear();
+
+	std::ifstream is((root_path + DIR_DELIM + m_mod_name).c_str(),
+			std::ios_base::binary);
+	if (!is.good()) {
+		return false;
+	}
+
+	Json::Value root;
+	Json::CharReaderBuilder builder;
+	builder.settings_["collectComments"] = false;
+	std::string errs;
+
+	if (!Json::parseFromStream(builder, is, &root, &errs)) {
+		errorstream << "ModMetadata[" << m_mod_name
+			    << "]: failed read data "
+			       "(Json decoding failure). Message: "
+			    << errs << std::endl;
+		return false;
+	}
+
+	const Json::Value::Members attr_list = root.getMemberNames();
+	for (const auto &it : attr_list) {
+		Json::Value attr_value = root[it];
+		m_stringvars[it] = attr_value.asString();
+	}
+
+	return true;
+}
+
+bool ModMetadata::setString(const std::string &name, const std::string &var)
+{
+	m_modified = Metadata::setString(name, var);
+	return m_modified;
+}
diff --git a/src/content/mods.h b/src/content/mods.h
new file mode 100644
index 000000000..a7cad07cf
--- /dev/null
+++ b/src/content/mods.h
@@ -0,0 +1,162 @@
+/*
+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"
+
+#define MODNAME_ALLOWED_CHARS "abcdefghijklmnopqrstuvwxyz0123456789_"
+
+struct ModSpec
+{
+	std::string name;
+	std::string author;
+	std::string path;
+	std::string desc;
+
+	// 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;
+
+	// if modpack:
+	std::map<std::string, ModSpec> modpack_content;
+	ModSpec(const std::string &name = "", const std::string &path = "") :
+			name(name), path(path)
+	{
+	}
+	ModSpec(const std::string &name, const std::string &path, bool part_of_modpack) :
+			name(name), path(path), part_of_modpack(part_of_modpack)
+	{
+	}
+};
+
+// Retrieves depends, optdepends, is_modpack and modpack_content
+void parseModContents(ModSpec &mod);
+
+std::map<std::string, ModSpec> getModsInPath(
+		const std::string &path, bool part_of_modpack = false);
+
+// replaces modpack Modspecs with their content
+std::vector<ModSpec> flattenMods(std::map<std::string, ModSpec> mods);
+
+// a ModConfiguration is a subset of installed mods, expected to have
+// all dependencies fullfilled, so it can be used as a list of mods to
+// load when the game starts.
+class ModConfiguration
+{
+public:
+	// checks if all dependencies are fullfilled.
+	bool isConsistent() const { return m_unsatisfied_mods.empty(); }
+
+	const std::vector<ModSpec> &getMods() const { return m_sorted_mods; }
+
+	const std::vector<ModSpec> &getUnsatisfiedMods() const
+	{
+		return m_unsatisfied_mods;
+	}
+
+	void printUnsatisfiedModsError() const;
+
+protected:
+	ModConfiguration(const std::string &worldpath);
+	// adds all mods in the given path. used for games, modpacks
+	// and world-specific mods (worldmods-folders)
+	void addModsInPath(const std::string &path);
+
+	// adds all mods in the set.
+	void addMods(const std::vector<ModSpec> &new_mods);
+
+	void addModsFromConfig(const std::string &settings_path,
+			const std::set<std::string> &mods);
+
+	void checkConflictsAndDeps();
+
+protected:
+	// list of mods sorted such that they can be loaded in the
+	// given order with all dependencies being fullfilled. I.e.,
+	// every mod in this list has only dependencies on mods which
+	// appear earlier in the vector.
+	std::vector<ModSpec> m_sorted_mods;
+
+private:
+	// 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;
+
+	// Deleted default constructor
+	ModConfiguration() = default;
+};
+
+#ifndef SERVER
+class ClientModConfiguration : public ModConfiguration
+{
+public:
+	ClientModConfiguration(const std::string &path);
+};
+#endif
+
+class ModMetadata : public Metadata
+{
+public:
+	ModMetadata() = delete;
+	ModMetadata(const std::string &mod_name);
+	~ModMetadata() = default;
+
+	virtual void clear();
+
+	bool save(const std::string &root_path);
+	bool load(const std::string &root_path);
+
+	bool isModified() const { return m_modified; }
+	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;
+	bool m_modified = false;
+};
diff --git a/src/content/packages.cpp b/src/content/packages.cpp
new file mode 100644
index 000000000..a769c31af
--- /dev/null
+++ b/src/content/packages.cpp
@@ -0,0 +1,68 @@
+/*
+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 "content/packages.h"
+#include "log.h"
+#include "filesys.h"
+#include "porting.h"
+#include "settings.h"
+#include "content/mods.h"
+#include "content/subgames.h"
+
+#if USE_CURL
+std::vector<Package> getPackagesFromURL(const std::string &url)
+{
+	std::vector<std::string> extra_headers;
+	extra_headers.emplace_back("Accept: application/json");
+
+	Json::Value json = fetchJsonValue(url, &extra_headers);
+	if (!json.isArray()) {
+		errorstream << "Invalid JSON download " << std::endl;
+		return std::vector<Package>();
+	}
+
+	std::vector<Package> packages;
+
+	// Note: `unsigned int` is required to index JSON
+	for (unsigned int i = 0; i < json.size(); ++i) {
+		Package package;
+
+		package.name = json[i]["name"].asString();
+		package.title = json[i]["title"].asString();
+		package.author = json[i]["author"].asString();
+		package.type = json[i]["type"].asString();
+		package.shortDesc = json[i]["shortDesc"].asString();
+		package.url = json[i]["url"].asString();
+
+		Json::Value jScreenshots = json[i]["screenshots"];
+		for (unsigned int j = 0; j < jScreenshots.size(); ++j) {
+			package.screenshots.push_back(jScreenshots[j].asString());
+		}
+
+		if (package.valid()) {
+			packages.push_back(package);
+		} else {
+			errorstream << "Invalid package at " << i << std::endl;
+		}
+	}
+
+	return packages;
+}
+
+#endif
diff --git a/src/content/packages.h b/src/content/packages.h
new file mode 100644
index 000000000..6774678de
--- /dev/null
+++ b/src/content/packages.h
@@ -0,0 +1,49 @@
+/*
+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"
+
+struct Package
+{
+	std::string name; // Technical name
+	std::string title;
+	std::string author;
+	std::string type; // One of "mod", "game", or "txp"
+
+	std::string shortDesc;
+	std::string url; // download URL
+	std::vector<std::string> screenshots;
+
+	bool valid()
+	{
+		return !(name.empty() || title.empty() || author.empty() ||
+				type.empty() || url.empty());
+	}
+};
+
+#if USE_CURL
+std::vector<Package> getPackagesFromURL(const std::string &url);
+#else
+inline std::vector<Package> getPackagesFromURL(const std::string &url)
+{
+	return std::vector<Package>();
+}
+#endif
diff --git a/src/content/subgames.cpp b/src/content/subgames.cpp
new file mode 100644
index 000000000..fd6231a1f
--- /dev/null
+++ b/src/content/subgames.cpp
@@ -0,0 +1,332 @@
+/*
+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 "content/subgames.h"
+#include "porting.h"
+#include "filesys.h"
+#include "settings.h"
+#include "log.h"
+#include "util/strfnd.h"
+#include "defaultsettings.h" // for override_default_settings
+#include "mapgen/mapgen.h"   // for MapgenParams
+#include "util/string.h"
+
+#ifndef SERVER
+#include "client/tile.h" // getImagePath
+#endif
+
+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());
+}
+
+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);
+		find_paths.emplace_back(path + DIR_DELIM + id, false);
+		find_paths.emplace_back(path + DIR_DELIM + id + "_game", false);
+	}
+	find_paths.emplace_back(
+			user + DIR_DELIM + "games" + DIR_DELIM + id + "_game", true);
+	find_paths.emplace_back(user + DIR_DELIM + "games" + DIR_DELIM + id, true);
+	find_paths.emplace_back(
+			share + DIR_DELIM + "games" + DIR_DELIM + id + "_game", false);
+	find_paths.emplace_back(share + DIR_DELIM + "games" + DIR_DELIM + id, 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::set<std::string> mods_paths;
+	if (!user_game)
+		mods_paths.insert(share + DIR_DELIM + "mods");
+	if (user != share || user_game)
+		mods_paths.insert(user + DIR_DELIM + "mods");
+
+	// Get meta
+	std::string conf_path = game_path + DIR_DELIM + "game.conf";
+	Settings conf;
+	conf.readConfigFile(conf_path.c_str());
+
+	std::string game_name;
+	if (conf.exists("name"))
+		game_name = conf.get("name");
+	else
+		game_name = id;
+
+	std::string game_author;
+	if (conf.exists("author"))
+		game_author = conf.get("author");
+
+	std::string menuicon_path;
+#ifndef SERVER
+	menuicon_path = getImagePath(
+			game_path + DIR_DELIM + "menu" + DIR_DELIM + "icon.png");
+#endif
+	return SubgameSpec(id, game_path, gamemod_path, mods_paths, game_name,
+			menuicon_path, game_author);
+}
+
+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("name"))
+			gamespec.name = conf.get("name");
+		else
+			gamespec.name = 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();
+	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"));
+}
+
+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::endl;
+		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 = 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;
+}
+
+bool loadGameConfAndInitWorld(const std::string &path, const SubgameSpec &gamespec)
+{
+	// Override defaults with those provided by the game.
+	// We clear and reload the defaults because the defaults
+	// might have been overridden by other subgame config
+	// files that were loaded before.
+	g_settings->clearDefaults();
+	set_default_settings(g_settings);
+	Settings game_defaults;
+	getGameMinetestConfig(gamespec.path, game_defaults);
+	override_default_settings(g_settings, &game_defaults);
+
+	infostream << "Initializing world at " << path << std::endl;
+
+	fs::CreateAllDirs(path);
+
+	// Create world.mt if does not already exist
+	std::string worldmt_path = path + DIR_DELIM "world.mt";
+	if (!fs::PathExists(worldmt_path)) {
+		Settings conf;
+
+		conf.set("gameid", gamespec.id);
+		conf.set("backend", "sqlite3");
+		conf.set("player_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()))
+			return false;
+	}
+
+	// Create map_meta.txt if does not already exist
+	std::string map_meta_path = path + DIR_DELIM + "map_meta.txt";
+	if (!fs::PathExists(map_meta_path)) {
+		verbosestream << "Creating map_meta.txt (" << map_meta_path << ")"
+			      << std::endl;
+		fs::CreateAllDirs(path);
+		std::ostringstream oss(std::ios_base::binary);
+
+		Settings conf;
+		MapgenParams params;
+
+		params.readParams(g_settings);
+		params.writeParams(&conf);
+		conf.writeLines(oss);
+		oss << "[end_of_params]\n";
+
+		fs::safeWriteToFile(map_meta_path, oss.str());
+	}
+	return true;
+}
diff --git a/src/content/subgames.h b/src/content/subgames.h
new file mode 100644
index 000000000..70a9d2713
--- /dev/null
+++ b/src/content/subgames.h
@@ -0,0 +1,90 @@
+/*
+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 <vector>
+
+class Settings;
+
+struct SubgameSpec
+{
+	std::string id;
+	std::string name;
+	std::string author;
+	std::string path;
+	std::string gamemods_path;
+	std::set<std::string> addon_mods_paths;
+	std::string menuicon_path;
+
+	SubgameSpec(const std::string &id = "", const std::string &path = "",
+			const std::string &gamemods_path = "",
+			const std::set<std::string> &addon_mods_paths =
+					std::set<std::string>(),
+			const std::string &name = "",
+			const std::string &menuicon_path = "",
+			const std::string &author = "") :
+			id(id),
+			name(name), author(author), path(path),
+			gamemods_path(gamemods_path), addon_mods_paths(addon_mods_paths),
+			menuicon_path(menuicon_path)
+	{
+	}
+
+	bool isValid() const { return (!id.empty() && !path.empty()); }
+};
+
+// minetest.conf
+bool getGameMinetestConfig(const std::string &game_path, Settings &conf);
+
+SubgameSpec findSubgame(const std::string &id);
+SubgameSpec findWorldSubgame(const std::string &world_path);
+
+std::set<std::string> getAvailableGameIds();
+std::vector<SubgameSpec> getAvailableGames();
+
+bool getWorldExists(const std::string &world_path);
+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
+bool loadGameConfAndInitWorld(const std::string &path, const SubgameSpec &gamespec);