timeout

# File lib/timeout.rb, line 52
  def timeout(sec, klass = nil)
    return yield if sec == nil or sec.zero?
    raise ThreadError, "timeout within critical session" if Thread.critical
    exception = klass || Class.new(ExitException)
    begin
      x = Thread.current
      y = Thread.start {
        sleep sec
        x.raise exception, "execution expired" if x.alive?
      }
      yield sec
      #    return true
    rescue exception => e
      rej = /\A#{Regexp.quote(__FILE__)}:#{__LINE__-4}\z/o
      (bt = e.backtrace).reject! {|m| rej =~ m}
      level = -caller(CALLER_OFFSET).size
      while THIS_FILE =~ bt[level]
        bt.delete_at(level)
        level += 1
      end
      raise if klass            # if exception class is specified, it
                                # would be expected outside.
      raise Error, e.message, e.backtrace
    ensure
      y.kill if y and y.alive?
    end
  end