check_registry

# File lib/uri/generic.rb, line 435
    def check_registry(v)
      return v unless v

      # raise if both server and registry are not nil, because:
      # authority     = server | reg_name
      # server        = [ [ userinfo "@" ] hostport ]
      if @host || @port || @user # userinfo = @user + ':' + @password
        raise InvalidURIError, 
          "can not set registry with host, port, or userinfo"
      elsif v && REGISTRY !~ v
        raise InvalidComponentError,
          "bad component(expected registry component): #{v}"
      end

      return true
    end