config: allow reading INI from string, file, default and current config

This (slightly more complicated implementation) allows us,
once a configuration menu has been implemented,
to store the current/new configuration to a INI file.

The definitions of the parameters in rwgame/GameConfig.cpp
is limited to one location.

rwgame/GameBase.cpp

@@ -13,6 +13,10 @@ GameBase::GameBase(Logger &inlog, int argc, char *argv[]) : log(inlog) {
     log.info("Game", "Build: " + kBuildStr);
 
     if (!config.isValid()) {
+        log.error("Config", "Invalid INI file at \""
+            + config.getConfigFile() + "\".\n"
+            + "Adapt the following default INI to your configuration.\n"
+            + config.getDefaultINIString());
         throw std::runtime_error("Invalid configuration file at: " +
                                  config.getConfigFile());
     }

rwgame/GameConfig.cpp

@@ -22,14 +22,15 @@ GameConfig::GameConfig(const std::string& configName,
     // Look up the path to use
     auto configFile = getConfigFile();
 
-    m_valid = readConfig(configFile);
+    std::string dummy;
+    m_valid = parseConfig(ParseType::FILE, configFile, ParseType::CONFIG, dummy);
 }
 
-std::string GameConfig::getConfigFile() {
+std::string GameConfig::getConfigFile() const {
     return m_configPath + "/" + m_configName;
 }
 
-bool GameConfig::isValid() {
+bool GameConfig::isValid() const {
     return m_valid;
 }
 
@@ -60,8 +61,7 @@ std::string GameConfig::getDefaultConfigPath() {
     return ".";
 }
 
-std::string stripComments(const std::string &str)
+std::string stripComments(const std::string &str) {
-{
     auto s = std::string(str, 0, str.find_first_of(";#"));
     return s.erase(s.find_last_not_of(" \n\r\t")+1);
 }
@@ -88,50 +88,139 @@ struct BoolTranslator {
     }
 };
 
-bool GameConfig::readConfig(const std::string &path) {
+struct IntTranslator {
-    pt::ptree config, defaultConfig;
+    typedef std::string internal_type;
+    typedef int         external_type;
+    boost::optional<external_type> get_value(const internal_type &str) {
+        return boost::optional<external_type>(std::stoi(stripComments(str)));
+    }
+    boost::optional<internal_type> put_value(const external_type &i) {
+        return boost::optional<internal_type>(std::to_string(i));
+    }
+};
+
+std::string GameConfig::getDefaultINIString() {
+    std::string result;
+    parseConfig(ParseType::DEFAULT, "", ParseType::STRING, result);
+    return result;
+}
+
+bool GameConfig::parseConfig(
+    GameConfig::ParseType srcType, const std::string &source,
+    ParseType destType, std::string &destination)
+{
     bool success = true;
+    pt::ptree srcTree;
+
+    if ((srcType == ParseType::STRING) || (srcType == ParseType::FILE)) {
+        std::istream *istream = nullptr;
+        switch (srcType) {
+            case ParseType::STRING:
+                istream = new std::istringstream(source);
+                break;
+            case ParseType::FILE:
+                istream = new std::ifstream(source);
+                break;
+            default:
+                //Cannot reach here
+                success = false;
+                break;
+        }
+        if (istream != nullptr) {
+            try {
+                pt::read_ini(*istream, srcTree);
+            } catch (pt::ini_parser_error &e) {
+                success = false;
+                RW_MESSAGE(e.what());
+            }
+        } else {
+            success = false;
+            RW_MESSAGE("Unable to create stream from source.");
+        }
+        delete istream;
+    }
 
     auto read_config = [&](const std::string &key, auto &target,
                           const auto &defaultValue, auto &translator,
                           bool optional=true) {
-        typedef typename std::remove_reference<decltype(target)>::type targetType;
+        typedef typename std::remove_reference<decltype(target)>::type config_t;
-        defaultConfig.put(key, defaultValue, translator);
+
+        config_t sourceValue;
+
+        switch (srcType) {
+            case ParseType::DEFAULT:
+                sourceValue = defaultValue;
+                break;
+            case ParseType::CONFIG:
+                sourceValue = target;
+                break;
+            case ParseType::FILE:
+            case ParseType::STRING:
                 try {
-            target = config.get<targetType>(key, translator);
+                    sourceValue = srcTree.get<config_t>(key, translator);
                 } catch (pt::ptree_bad_path &e) {
                     if (optional) {
-              target = defaultValue;
+                        sourceValue = defaultValue;
                     } else {
                       success = false;
                       RW_MESSAGE(e.what());
                     }
                 }
-    };
+                break;
-
-    try {
-        pt::read_ini(path, config);
-    } catch (pt::ini_parser_error &e) {
-        success = false;
-        RW_MESSAGE(e.what());
         }
+        srcTree.put(key, sourceValue, translator);
+
+        switch (destType) {
+            case ParseType::DEFAULT:
+                RW_ERROR("Target cannot be DEFAULT.");
+                success = false;
+                break;
+            case ParseType::CONFIG:
+                //Don't care if success == false
+                target = sourceValue;
+                break;
+            case ParseType::FILE:
+            case ParseType::STRING:
+                break;
+        }
+    };
 
     auto deft = StringTranslator();
     auto boolt = BoolTranslator();
 
-    // @todo Don't allow path seperators and relative directories
+    //Add new configuration parameters here.
+
+    // @todo Don't allow path separators and relative directories
     read_config("game.path", this->m_gamePath, "/opt/games/Grand Theft Auto 3", deft, false);
     read_config("game.language", this->m_gameLanguage, "american", deft);
 
     read_config("input.invert_y", this->m_inputInvertY, false, boolt);
 
-    if (!success) {
+    if ((destType == ParseType::STRING) || (destType == ParseType::FILE)) {
-        std::stringstream strstream;
+        std::ostringstream ostream;
-        pt::write_ini(strstream, defaultConfig);
+        try {
-
+            pt::write_ini(ostream, srcTree);
-        RW_MESSAGE("Failed to parse configuration file (" + path + ").");
+        } catch (pt::ini_parser_error &e) {
-        RW_MESSAGE("Create one looking like this at \"" + path + "\":");
+            success = false;
-        RW_MESSAGE(strstream.str());
+            RW_MESSAGE(e.what());
+        }
+        switch (destType) {
+            case ParseType::STRING:
+                destination = ostream.str();
+                break;
+            case ParseType::FILE:
+            {
+                std::ofstream ofs(destination);
+                ofs << ostream.str();
+                ofs.close();
+                success &= !ofs.fail();
+                break;
+            }
+            default:
+                //Cannot reach here
+                success = false;
+                break;
+        }
     }
 
     return success;

rwgame/GameConfig.hpp

@@ -15,13 +15,19 @@ public:
     /**
      * @brief getFilePath Returns the system file path for the configuration
      */
-    std::string getConfigFile();
+    std::string getConfigFile() const;
 
     /**
      * @brief isValid
      * @return True if the loaded configuration is valid
      */
-    bool isValid();
+    bool isValid() const;
+
+    /**
+     * @brief getConfigString Returns the content of the default INI configuration.
+     * @return INI string
+     */
+    std::string getDefaultINIString();
 
     const std::string& getGameDataPath() const {
         return m_gamePath;
@@ -36,7 +42,27 @@ public:
 private:
     static std::string getDefaultConfigPath();
 
-    bool readConfig(const std::string &path);
+    enum ParseType {
+        DEFAULT,
+        CONFIG,
+        FILE,
+        STRING
+    };
+
+    /**
+     * @brief parseConfig Load data from source and write it to destination.
+     * @param srcType Can be DEFAULT | CONFIG | FILE | STRING
+     * @param source don't care if srcType == (DEFAULT | CONFIG),
+     *               path of INI file if srcType == FILE
+     *               INI string if srcType == STRING
+     * @param destType Can be CONFIG | FILE | STRING (DEFAULT is invalid)
+     * @param destination don't care if srcType == CONFIG
+     *                    path of INI file if destType == FILE
+     *                    INI string if srcType == STRING
+     * @return True if the parsing succeeded
+     */
+    bool parseConfig(ParseType srcType, const std::string &source,
+        ParseType destType, std::string &destination);
 
     /* Config State */
     std::string m_configName;

tests/test_config.cpp

@@ -4,6 +4,7 @@
 
 BOOST_AUTO_TEST_SUITE(ConfigTests)
 
+
 BOOST_AUTO_TEST_CASE(test_loading) {
     // Write out a temporary file
     std::ofstream test_config("/tmp/openrw_test.ini");
@@ -20,6 +21,7 @@ BOOST_AUTO_TEST_CASE(test_loading) {
 
     BOOST_CHECK_EQUAL(config.getGameDataPath(), "/dev/test");
     BOOST_CHECK_EQUAL(config.getGameLanguage(), "american");
+    BOOST_CHECK_EQUAL(config.getInputInvertY(), false);
 }