add_file

# File lib/rubygems/package/tar_writer.rb, line 105
  def add_file(name, mode) # :yields: io
    check_closed

    raise Gem::Package::NonSeekableIO unless @io.respond_to? :pos=

    name, prefix = split_name name

    init_pos = @io.pos
    @io.write "\00"" * 512 # placeholder for the header

    yield RestrictedStream.new(@io) if block_given?

    size = @io.pos - init_pos - 512

    remainder = (512 - (size % 512)) % 512
    @io.write "\00"" * remainder

    final_pos = @io.pos
    @io.pos = init_pos

    header = Gem::Package::TarHeader.new :name => name, :mode => mode,
                                         :size => size, :prefix => prefix,
                                         :mtime => Time.now

    @io.write header
    @io.pos = final_pos

    self
  end