module ActionController
  class Reloader
    class BodyWrapper
      def initialize(body)
        @body = body
      end

      def close
        @body.close if @body.respond_to?(:close)
      ensure
        Dispatcher.cleanup_application
      end

      def method_missing(*args, &block)
        @body.send(*args, &block)
      end

      def respond_to?(symbol, include_private = false)
        symbol == :close || @body.respond_to?(symbol, include_private)
      end
    end

    def initialize(app)
      @app = app
    end

    def call(env)
      Dispatcher.reload_application
      status, headers, body = @app.call(env)
      # We do not want to call 'cleanup_application' in an ensure block
      # because the returned Rack response body may lazily generate its data. This
      # is for example the case if one calls
      #
      #   render :text => lambda { ... code here which refers to application models ... }
      #
      # in an ActionController.
      #
      # Instead, we will want to cleanup the application code after the request is
      # completely finished. So we wrap the body in a BodyWrapper class so that
      # when the Rack handler calls #close during the end of the request, we get to
      # run our cleanup code.
      [status, headers, BodyWrapper.new(body)]
    end
  end
end