file_exist?

# File actionpack/lib/action_view/helpers/asset_tag_helper.rb, line 401
        def file_exist?(path)
          @@file_exist_cache ||= {}
          if !(@@file_exist_cache[path] ||= File.exist?(path))
            @@file_exist_cache[path] = true
            false
          else
            true
          end
        end