register static method

bool register(String root, void register(String name, Object? handler(Object?)))

Registers the three bindings, confined to root.

Returns false where there is no filesystem to bind to, leaving the bindings unregistered rather than half-registered.

Implementation

static bool register(
  String root,
  void Function(String name, Object? Function(Object?) handler) register,
) {
  if (_registered) return true;

  final Directory directory = Directory(root);
  try {
    if (!directory.existsSync()) directory.createSync(recursive: true);
  } on FileSystemException {
    return false;
  }
  _root = directory.absolute.path;

  register('files.readBytes', (Object? arguments) {
    final File file = File(_resolve(_pathOf(arguments)));
    if (!file.existsSync()) {
      throw ArgumentError('files.readBytes: "${_pathOf(arguments)}" '
          'does not exist.');
    }
    return file.readAsBytesSync();
  });

  register('files.writeBytes', (Object? arguments) {
    final Map<Object?, Object?> map =
        arguments is Map ? arguments : const <Object?, Object?>{};
    final Object? bytes = map['bytes'];
    if (bytes is! List<int>) {
      // Refused rather than coerced. Writing the string form of a list is a
      // file that looks written and contains the wrong thing.
      throw ArgumentError(
        'files.writeBytes needs a List<int> in "bytes", got '
        '${bytes.runtimeType}.',
      );
    }
    final File file = File(_resolve(_pathOf(arguments)));
    file.parent.createSync(recursive: true);
    file.writeAsBytesSync(Uint8List.fromList(bytes), flush: true);
    // True, not the count. DVFiles.writeBytes asks through require<bool>, so
    // a count threw "returned int, expected bool" and made the binding
    // unusable on every target with a filesystem -- while the file on disk
    // was perfectly correct. files.delete beside it answers bool, and web
    // answers bool, so the count was the outlier as well as the fault.
    return true;
  });

  register('files.delete', (Object? arguments) {
    final File file = File(_resolve(_pathOf(arguments)));
    // Deleting what is not there is the caller's intent either way, and
    // throwing would make every caller wrap it.
    if (!file.existsSync()) return false;
    file.deleteSync();
    return true;
  });

  _registered = true;
  return true;
}