    # File install.rb, line 22
    def cvs_files(dir)
      return CVS_FILES[dir] if CVS_FILES.include? dir
      if File.directory? "#{dir}/CVS"
        result = {}
        File.foreach("#{dir}/CVS/Entries") {|line|
          case line
          when %r{\A/([^/]+)/} then result[$1] = true
          when %r{\AD/([^/]+)/} then result[$1] = true
          end
        }
      else
        result = nil
      end
      CVS_FILES[dir] = result
      result
    end