# File lib/xml/saxdriver.rb, line 184
      def xmlOpen(base, systemId, publicId)
        if base.nil? || base == ""
          file = URL.new(systemId)
        else
          file = URL.new(URL.new(base), systemId)
        end
        if !@entityResolver.nil?
          stream = @entityResolver.resolveEntity(file.to_s, publicId)
          return openInputStream(stream) if stream
        end
        if file.scheme == 'file' && file.login == 'localhost'
          stream = open(file.urlpath)
          is = XML::SAX::InputSource.new(stream)
          is.setSystemId(file.to_s)
          is.setPublicId(publicId)
          return is
        end
      end