class ActionDispatch::Static

def call(env)
  path   = env['PATH_INFO'].chomp('/')
  method = env['REQUEST_METHOD']
  if FILE_METHODS.include?(method)
    if file_exist?(path)
      return @file_server.call(env)
    else
      cached_path = directory_exist?(path) ? "#{path}/index" : path
      cached_path += ::ActionController::Base.page_cache_extension
      if file_exist?(cached_path)
        env['PATH_INFO'] = cached_path
        return @file_server.call(env)
      end
    end
  end
  @app.call(env)
end

def directory_exist?(path)
  full_path = File.join(@file_server.root, ::Rack::Utils.unescape(path))
  File.directory?(full_path) && File.readable?(full_path)
end

def file_exist?(path)
  full_path = File.join(@file_server.root, ::Rack::Utils.unescape(path))
  File.file?(full_path) && File.readable?(full_path)
end

def initialize(app, root)
  @app = app
  @file_server = ::Rack::File.new(root)
end