probe_stat_in

# File activesupport/lib/active_support/core_ext/file/atomic.rb, line 49
  def self.probe_stat_in(dir) #:nodoc:
    basename = [
      '.permissions_check',
      Thread.current.object_id,
      Process.pid,
      rand(1000000)
    ].join('.')

    file_name = join(dir, basename)
    FileUtils.touch(file_name)
    stat(file_name)
  ensure
    FileUtils.rm_f(file_name) if file_name
  end