Service::CFG/FS: add and refactor out utilities for front-end

src/core/hle/service/cfg/cfg.h

@@ -5,6 +5,7 @@
 #pragma once
 
 #include <array>
+#include <string>
 
 #include "common/common_types.h"
 
@@ -271,11 +272,70 @@ ResultCode UpdateConfigNANDSavegame();
  */
 ResultCode FormatConfig();
 
+/**
+ * Open the config savegame file and load it to the memory buffer
+ * @returns ResultCode indicating the result of the operation, 0 on success
+ */
+ResultCode LoadConfigNANDSaveFile();
+
 /// Initialize the config service
 void Init();
 
 /// Shutdown the config service
 void Shutdown();
 
+// Utilities for frontend to set config data.
+// Note: before calling these functions, LoadConfigNANDSaveFile should be called,
+// and UpdateConfigNANDSavegame should be called after making changes to config data.
+
+/**
+ * Sets the username in config savegame.
+ * @param name the username to set. The maximum size is 10 in char16_t.
+ */
+void SetUsername(const std::u16string& name);
+
+/**
+ * Gets the username from config savegame.
+ * @returns the username
+ */
+std::u16string GetUsername();
+
+/**
+ * Sets the profile birthday in config savegame.
+ * @param month the month of birthday.
+ * @param day the day of the birthday.
+ */
+void SetBirthday(u8 month, u8 day);
+
+/**
+ * Gets the profile birthday from the config savegame.
+ * @returns a tuple of (month, day) of birthday
+ */
+std::tuple<u8, u8> GetBirthday();
+
+/**
+ * Sets the system language in config savegame.
+ * @param language the system language to set.
+ */
+void SetSystemLanguage(SystemLanguage language);
+
+/**
+ * Gets the system language from config savegame.
+ * @returns the system language
+ */
+SystemLanguage GetSystemLanguage();
+
+/**
+ * Sets the sound output mode in config savegame.
+ * @param mode the sound output mode to set
+ */
+void SetSoundOutputMode(SoundOutputMode mode);
+
+/**
+ * Gets the sound output mode from config savegame.
+ * @returns the sound output mode
+ */
+SoundOutputMode GetSoundOutputMode();
+
 } // namespace CFG
 } // namespace Service