class Twig_Extension_Escaper

class Twig_Extension_Escaper extends Twig_Extension {
  protected $defaultStrategy;
  public function __construct($defaultStrategy = 'html') {
    $this
      ->setDefaultStrategy($defaultStrategy);
  }

  /**
   * Returns the token parser instances to add to the existing list.
   *
   * @return array An array of Twig_TokenParserInterface or Twig_TokenParserBrokerInterface instances
   */
  public function getTokenParsers() {
    return array(
      new Twig_TokenParser_AutoEscape(),
    );
  }

  /**
   * Returns the node visitor instances to add to the existing list.
   *
   * @return array An array of Twig_NodeVisitorInterface instances
   */
  public function getNodeVisitors() {
    return array(
      new Twig_NodeVisitor_Escaper(),
    );
  }

  /**
   * Returns a list of filters to add to the existing list.
   *
   * @return array An array of filters
   */
  public function getFilters() {
    return array(
      'raw' => new Twig_Filter_Function('twig_raw_filter', array(
        'is_safe' => array(
          'all',
        ),
      )),
    );
  }

  /**
   * Sets the default strategy to use when not defined by the user.
   *
   * The strategy can be a valid PHP callback that takes the template
   * "filename" as an argument and returns the strategy to use.
   *
   * @param mixed $defaultStrategy An escaping strategy
   */
  public function setDefaultStrategy($defaultStrategy) {

    // for BC
    if (true === $defaultStrategy) {
      $defaultStrategy = 'html';
    }
    $this->defaultStrategy = $defaultStrategy;
  }

  /**
   * Gets the default strategy to use when not defined by the user.
   *
   * @param string $filename The template "filename"
   *
   * @return string The default strategy to use for the template
   */
  public function getDefaultStrategy($filename) {

    // disable string callables to avoid calling a function named html or js,
    // or any other upcoming escaping strategy
    if (!is_string($this->defaultStrategy) && is_callable($this->defaultStrategy)) {
      return call_user_func($this->defaultStrategy, $filename);
    }
    return $this->defaultStrategy;
  }

  /**
   * Returns the name of the extension.
   *
   * @return string The extension name
   */
  public function getName() {
    return 'escaper';
  }

}