# File lib/sass/importers/filesystem.rb, line 69
      def public_url(name, sourcemap_directory)
        file_pathname = Sass::Util.cleanpath(Sass::Util.absolute_path(name, @root))
        return Sass::Util.file_uri_from_path(file_pathname) if sourcemap_directory.nil?

        sourcemap_pathname = Sass::Util.cleanpath(sourcemap_directory)
        begin
          Sass::Util.file_uri_from_path(
            Sass::Util.relative_path_from(file_pathname, sourcemap_pathname))
        rescue ArgumentError # when a relative path cannot be constructed
          Sass::Util.file_uri_from_path(file_pathname)
        end
      end