refactor: migrate windows specific content.

- move com, dialog and winfct function into new place.
- add testbench for com and winfct.
- dialog now still not working.

src/yycc/windows/winfct.hpp

@@ -0,0 +1,116 @@
+#pragma once
+#include "../macro/os_detector.hpp"
+#include "../macro/stl_detector.hpp"
+#if defined(YYCC_OS_WINDOWS)
+
+#include <string>
+#include <string_view>
+#include <expected>
+
+#include "import_guard_head.hpp"
+#include <Windows.h>
+#include "import_guard_tail.hpp"
+
+namespace yycc::windows::winfct {
+
+    /// @brief All errors occur in this module.
+    enum class WinFctError {
+        Backend,  ///< Error occurs when calling Win32 functions.
+        Encoding, ///< Can not perform encoding convertion.
+        NoCom,    ///< No COM environment.
+    };
+
+    /// @brief The result type used in this module.
+    template<typename T>
+    using WinFctResult = std::expected<T, WinFctError>;
+
+    /**
+	 * @brief Get Windows used HANDLE for current module.
+	 * @details
+	 * If your target is EXE, the current module simply is your program self.
+	 * However, if your target is DLL, the current module is your DLL, not the EXE loading your DLL.
+	 * 
+	 * This function is frequently used by DLL.
+	 * Because some design need the HANDLE of current module, not the host EXE loading your DLL.
+	 * For example, you may want to get the path of your built DLL, or fetch resources from your DLL at runtime,
+	 * then you should pass current module HANDLE, not NULL or the HANDLE of EXE.
+	 * @return A Windows HANDLE pointing to current module, or error occurs.
+	*/
+    WinFctResult<HMODULE> get_current_module();
+
+    /**
+	 * @brief Get path to Windows temporary directory.
+	 * @details Windows temporary directory usually is the target of \%TEMP\%.
+	 * @return Fetched UTF8 encoded path to Windows temporary directory, or error occurs.
+	*/
+    WinFctResult<std::u8string> get_temp_directory();
+
+    /**
+	 * @brief Get the file name of given module HANDLE
+	 * @param[in] hModule 
+	 * The HANDLE to the module where you want to get file name.
+	 * It is same as the HANDLE parameter of Win32 \c GetModuleFileName.
+	 * @param[out] ret The variable receiving UTF8 encoded file name of given module.
+	 * @return Fetched UTF8 encoded file name of given module, or error occurs.
+	*/
+    WinFctResult<std::u8string> get_module_file_name(HINSTANCE hModule);
+
+    /**
+	 * @brief Check whether given code page number is a valid one.
+	 * @param[in] code_page The code page number.
+	 * @return True if it is valid, otherwise false.
+	*/
+    bool is_valid_code_page(UINT code_page);
+
+    /**
+	 * @brief Copies an existing file to a new file.
+	 * @param[in] lpExistingFileName The name of an existing file.
+	 * @param[in] lpNewFileName The name of the new file.
+	 * @param[in] bFailIfExists 
+	 * If this parameter is TRUE and the new file specified by \c lpNewFileName already exists, the function fails.
+	 * If this parameter is FALSE and the new file already exists, the function overwrites the existing file and succeeds.
+	 * @return Nothing or error occurs. If function failed with backend error, caller can call \c GetLastError for more details.
+	 * @remarks Same as Windows \c CopyFile: https://learn.microsoft.com/en-us/windows/win32/api/winbase/nf-winbase-copyfilew
+	*/
+    WinFctResult<void> copy_file(const std::u8string_view& lpExistingFileName, const std::u8string_view& lpNewFileName, BOOL bFailIfExists);
+
+    /**
+	 * @brief Moves an existing file or a directory, including its children.
+	 * @param[in] lpExistingFileName The current name of the file or directory on the local computer.
+	 * @param[in] lpNewFileName 
+	 * The new name for the file or directory. The new name must not already exist.
+	 * A new file may be on a different file system or drive. A new directory must be on the same drive.
+	 * @return Nothing or error occurs. If function failed with backend error, caller can call \c GetLastError for more details.
+	 * @remarks Same as Windows \c MoveFile: https://learn.microsoft.com/en-us/windows/win32/api/winbase/nf-winbase-movefilew
+	*/
+    WinFctResult<void> move_file(const std::u8string_view& lpExistingFileName, const std::u8string_view& lpNewFileName);
+
+    /**
+	 * @brief Deletes an existing file.
+	 * @param[in] lpFileName The name of the file to be deleted.
+	 * @return Nothing or error occurs. If function failed with backend error, caller can call \c GetLastError for more details.
+	 * @remarks Same as Windows \c DeleteFile: https://learn.microsoft.com/e-us/windows/win32/api/winbase/nf-winbase-deletefile
+	*/
+    WinFctResult<void> delete_file(const std::u8string_view& lpFileName);
+
+#if defined(YYCC_STL_MSSTL)
+
+    /// @brief The known directory type in Windows.
+    enum class KnownDirectory {
+        LocalAppData, ///< The path \%LOCALAPPDATA\% pointed.
+        AppData, ///< The path \%APPDATA\% pointed.
+    };
+
+    /**
+     * @brief Get the path to \%LOCALAPPDATA\%.
+     * @details \%LOCALAPPDATA\% usually was used as putting local app data files
+     * @param[out] ret The variable receiving UTF8 encoded path to LOCALAPPDATA.
+     * @return True if success, otherwise false.
+    */
+    WinFctResult<std::u8string> get_known_path(KnownDirectory path_type);
+
+#endif
+
+}
+
+#endif