You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: filehandler.rb
    path of file: ./repos/jruby/test/tool/lib/webrick/httpservlet
    
    the code of the file until where you have to start completion: # frozen_string_literal: false
#
# filehandler.rb -- FileHandler Module
#
# Author: IPR -- Internet Programming with Ruby -- writers
# Copy
    
      def shift_path_info(req, res, path_info, base=nil)
        tmp = path_info.shift
        base = base || set_filesystem_encoding(tmp)
        req.path_info = path_info.join
        req.script_name << base
        res.filename = File.expand_path(res.filename + base)
        check_filename(req, res, File.basename(res.filename))
      end