# File lib/grit/git-ruby.rb, line 106
    def refs(options, prefix)
      refs = []
      already = {}
      Dir.chdir(@git_dir) do
        files = Dir.glob(prefix + '/**/*')
        files.each do |ref|
          next if !File.file?(ref)
          id = File.read(ref).chomp
          name = ref.sub("#{prefix}/", '')
          if !already[name]
            refs << "#{name} #{id}"
            already[name] = true
          end
        end

        if File.file?('packed-refs')
          File.readlines('packed-refs').each do |line|
            if m = /^(\w{40}) (.*?)$/.match(line)
              next if !Regexp.new('^' + prefix).match(m[2])
              name = m[2].sub("#{prefix}/", '')
              if !already[name]
                refs << "#{name} #{m[1]}"
                already[name] = true
              end
            end
          end
        end
      end

      refs.join("\n")
    end