getDirectory method

Implementation

Directory? getDirectory() {
  var didUserCancel = false;
  var path = '';

  final dialog = FileOpenDialog.createInstance();

  using((arena) {
    final pfos = arena<Uint32>();
    var hr = dialog.getOptions(pfos);
    if (FAILED(hr)) throw WindowsException(hr);

    var options = pfos.value;
    options |= FILEOPENDIALOGOPTIONS.FOS_PICKFOLDERS;
    if (hidePinnedPlaces) {
      options |= FILEOPENDIALOGOPTIONS.FOS_HIDEPINNEDPLACES;
    }
    if (fileMustExist) options |= FILEOPENDIALOGOPTIONS.FOS_PATHMUSTEXIST;
    if (isDirectoryFixed) options |= FILEOPENDIALOGOPTIONS.FOS_NOCHANGEDIR;
    if (forceFileSystemItems) {
      options |= FILEOPENDIALOGOPTIONS.FOS_FORCEFILESYSTEM;
    }

    hr = dialog.setOptions(options);
    if (FAILED(hr)) throw WindowsException(hr);

    if (title.isNotEmpty) {
      final pTitle = title.toNativeUtf16(allocator: arena);
      final hr = dialog.setTitle(pTitle);
      if (FAILED(hr)) throw WindowsException(hr);
    }

    if (initialDirectory case final initialDirectory?
        when initialDirectory.isNotEmpty) {
      final pszPath = initialDirectory.toNativeUtf16(allocator: arena);
      final riid = convertToIID(IID_IShellItem, allocator: arena);
      final ppv = calloc<Pointer>();
      var hr = SHCreateItemFromParsingName(
        pszPath,
        nullptr,
        riid,
        ppv,
      );
      if (FAILED(hr)) throw WindowsException(hr);

      final shellItem = IShellItem(ppv.cast());
      hr = alwaysShowInitialDirectory
          ? dialog.setFolder(shellItem.ptr.cast<Pointer<COMObject>>().value)
          : dialog.setDefaultFolder(
              shellItem.ptr.cast<Pointer<COMObject>>().value);
      if (FAILED(hr)) throw WindowsException(hr);
    }

    for (final place in customPlaces) {
      final hr = dialog.addPlace(
        place.item.ptr.cast<Pointer<COMObject>>().value,
        place.place == Place.bottom ? FDAP.FDAP_BOTTOM : FDAP.FDAP_TOP,
      );
      if (FAILED(hr)) throw WindowsException(hr);
    }

    hr = dialog.show(hWndOwner);
    if (FAILED(hr)) {
      if (hr == HRESULT_FROM_WIN32(WIN32_ERROR.ERROR_CANCELLED)) {
        didUserCancel = true;
      } else {
        throw WindowsException(hr);
      }
    } else {
      final ppsi = calloc<Pointer<COMObject>>();
      hr = dialog.getResult(ppsi);
      if (FAILED(hr)) throw WindowsException(hr);

      final item = IShellItem(ppsi.cast());
      final ppszName = arena<Pointer<Utf16>>();
      hr = item.getDisplayName(SIGDN.SIGDN_FILESYSPATH, ppszName);
      if (FAILED(hr)) throw WindowsException(hr);
      // MAX_PATH is the normal maximum, but if the process is set to support
      // long file paths and the user selects a path with length > MAX_PATH
      // characters, it could be longer. In this case, the file name will be
      // truncated.
      path = ppszName.value.toDartString();
    }
  });

  return didUserCancel ? null : Directory(path);
}