normalize_paths

# File actionpack/lib/action_controller/routing.rb, line 264
      def normalize_paths(paths)
        # do the hokey-pokey of path normalization...
        paths = paths.collect do |path|
          path = path.
            gsub("//", "/").           # replace double / chars with a single
            gsub("\\\\", "\\").        # replace double \ chars with a single
            gsub(%r{(.)[\\/]$}, '\1')  # drop final / or \ if path ends with it

          # eliminate .. paths where possible
          re = %r{\w+[/\\]\.\.[/\\]}
          path.gsub!(%r{\w+[/\\]\.\.[/\\]}, "") while path.match(re)
          path
        end

        # start with longest path, first
        paths = paths.uniq.sort_by { |path| - path.length }
      end