    # File lib/supplemental/facets/atomicfile.rb, line 23
      def self.write(file_name, temp_dir=nil)

        temp_dir  = temp_dir || Dir.tmpdir
        temp_file = Tempfile.new(basename(file_name), temp_dir)

        yield temp_file
        temp_file.close

        begin
          ## Get original file permissions
          old_stat = stat(file_name)
        rescue Errno::ENOENT
          ## No old permissions, write a temp file to determine the defaults
          check_name = join(dirname(file_name), ".permissions_check.#{Thread.current.object_id}.#{Process.pid}.#{rand(1000000)}")
          open(check_name, "w") { }
          old_stat = stat(check_name)
          unlink(check_name)
        end

        ## Overwrite original file with temp file
        FileUtils.mv(temp_file.path, file_name)

        ## Set correct permissions on new file
        chown(old_stat.uid, old_stat.gid, file_name)
        chmod(old_stat.mode, file_name)
      end