toFile method

Future<File> toFile(File file, { FileMode? mode, bool? overwriteExistingFile, })

This method uses a different approach in writing to a file. It uses a temp file to store the data and then renames it to the correct name. If overwriteExisting file is true, and a file with the same name exists, it is overwitten, otherwise a suffix like "(n)" is appended to the file name, where n is a progressive number not yet assigned to any existing file in the system

Implementation

Future<File> toFile(File file,
    {FileMode? mode, bool? overwriteExistingFile}) async {
  overwriteExistingFile ??= false;
  mode ??= FileMode.writeOnly;
  if (mode == FileMode.read) {
    throw ArgumentError('Read file mode not valid for method "toFile()"');
  }
  File tempFile;
  String tempFilePath = '${p.dirname(file.path)}${Platform.pathSeparator}'
      '${p.basenameWithoutExtension(file.path)}_${Uuid().v4()}'
      '${p.extension(file.path)}';
  if (mode == FileMode.append || mode == FileMode.writeOnlyAppend) {
    tempFile = await file.copy(tempFilePath);
  } else {
    tempFile = File(tempFilePath);
  }
  Future<void> addToFile(Map<String, dynamic> chunk) async {
    final bytes = chunk['data'] as BsonBinary;
    await tempFile.writeAsBytes(bytes.byteList,
        mode: FileMode.writeOnlyAppend, flush: true);
  }

  var chunkList =
      await fs.chunks.find(where.eq('files_id', id).sortBy('n')).toList();
  for (var chunk in chunkList) {
    await addToFile(chunk);
  }
  if (overwriteExistingFile) {
    return tempFile.changeFileNameOnly(file.name);
  }
  return tempFile.changeFileNameOnlySafe(file.name);
}