add_file_digest

# File lib/rubygems/package/tar_writer.rb, line 141
  def add_file_digest(name, mode, digest_algorithms) # :yields: io
    digests = digest_algorithms.map do |digest_algorithm|
      digest = digest_algorithm.new
      digest_name =
        if digest.respond_to? :name
          digest.name
        else
          /::([^:]+)$/ =~ digest_algorithm.name
          $1
        end

      [digest_name, digest]
    end

    digests = Hash[*digests.flatten]

    add_file name, mode do |io|
      Gem::Package::DigestIO.wrap io, digests do |digest_io|
        yield digest_io
      end
    end

    digests
  end