Add documentation comments and nodiscard attributes

include/Pomdog/Utility/FileSystem.hpp

@@ -8,33 +8,47 @@
 namespace Pomdog {
 
 struct POMDOG_EXPORT FileSystem final {
-    static bool CreateDirectory(const std::string& path);
+    /// Create a new directory with the specified path.
+    [[nodiscard]] static bool
+    CreateDirectory(const std::string& path);
 
-    static bool CreateDirectories(const std::string& path);
+    /// Create a new directory with the specified path.
+    [[nodiscard]] static bool
+    CreateDirectories(const std::string& path);
 
-    static bool Exists(const std::string& path);
+    /// Returns true if the file exists, false otherwise.
+    [[nodiscard]] static bool
+    Exists(const std::string& path);
 
-    static bool IsDirectory(const std::string& path);
+    /// Returns true if the file is directory, false otherwise.
+    [[nodiscard]] static bool
+    IsDirectory(const std::string& path);
 
     // Windows:
     // - "<user name>\Local Settings\Applicaiton Data\Pomdog"
     // - "C:\Users\<user name>\AppData\Local\Pomdog"
-    static std::string GetLocalAppDataDirectoryPath();
+    [[nodiscard]] static std::string
+    GetLocalAppDataDirectoryPath();
 
     // Windows:
     // - "<user name>\Application Data\Pomdog"
     // - "C:\Users\<user name>\AppData\Roaming\Pomdog"
-    static std::string GetAppDataDirectoryPath();
+    [[nodiscard]] static std::string
+    GetAppDataDirectoryPath();
 
     // Windows:
     // - "<current directory>"
-    static std::string GetResourceDirectoryPath();
+    [[nodiscard]] static std::string
+    GetResourceDirectoryPath();
 
     // Windows:
     // - "C:\Users\<user name>\AppData\Local\Temp"
-    static std::string GetTempDirectoryPath();
+    [[nodiscard]] static std::string
+    GetTempDirectoryPath();
 
-    static std::string GetCurrentWorkingDirectory();
+    /// Gets the current working directory.
+    [[nodiscard]] static std::string
+    GetCurrentWorkingDirectory();
 };
 
 } // namespace Pomdog