class Twig_NodeVisitor_Optimizer

class Twig_NodeVisitor_Optimizer implements Twig_NodeVisitorInterface {
  const OPTIMIZE_ALL = -1;
  const OPTIMIZE_NONE = 0;
  const OPTIMIZE_FOR = 2;
  const OPTIMIZE_RAW_FILTER = 4;
  const OPTIMIZE_VAR_ACCESS = 8;
  protected $loops = array();
  protected $optimizers;
  protected $prependedNodes = array();
  protected $inABody = false;

  /**
   * Constructor.
   *
   * @param integer $optimizers The optimizer mode
   */
  public function __construct($optimizers = -1) {
    if (!is_int($optimizers) || $optimizers > 2) {
      throw new InvalidArgumentException(sprintf('Optimizer mode "%s" is not valid.', $optimizers));
    }
    $this->optimizers = $optimizers;
  }

  /**
   * {@inheritdoc}
   */
  public function enterNode(Twig_NodeInterface $node, Twig_Environment $env) {
    if (self::OPTIMIZE_FOR === (self::OPTIMIZE_FOR & $this->optimizers)) {
      $this
        ->enterOptimizeFor($node, $env);
    }
    if (!version_compare(phpversion(), '5.4.0RC1', '>=') && self::OPTIMIZE_VAR_ACCESS === (self::OPTIMIZE_VAR_ACCESS & $this->optimizers) && !$env
      ->isStrictVariables() && !$env
      ->hasExtension('sandbox')) {
      if ($this->inABody) {
        if (!$node instanceof Twig_Node_Expression) {
          if (get_class($node) !== 'Twig_Node') {
            array_unshift($this->prependedNodes, array());
          }
        }
        else {
          $node = $this
            ->optimizeVariables($node, $env);
        }
      }
      elseif ($node instanceof Twig_Node_Body) {
        $this->inABody = true;
      }
    }
    return $node;
  }

  /**
   * {@inheritdoc}
   */
  public function leaveNode(Twig_NodeInterface $node, Twig_Environment $env) {
    $expression = $node instanceof Twig_Node_Expression;
    if (self::OPTIMIZE_FOR === (self::OPTIMIZE_FOR & $this->optimizers)) {
      $this
        ->leaveOptimizeFor($node, $env);
    }
    if (self::OPTIMIZE_RAW_FILTER === (self::OPTIMIZE_RAW_FILTER & $this->optimizers)) {
      $node = $this
        ->optimizeRawFilter($node, $env);
    }
    $node = $this
      ->optimizePrintNode($node, $env);
    if (self::OPTIMIZE_VAR_ACCESS === (self::OPTIMIZE_VAR_ACCESS & $this->optimizers) && !$env
      ->isStrictVariables() && !$env
      ->hasExtension('sandbox')) {
      if ($node instanceof Twig_Node_Body) {
        $this->inABody = false;
      }
      elseif ($this->inABody) {
        if (!$expression && get_class($node) !== 'Twig_Node' && ($prependedNodes = array_shift($this->prependedNodes))) {
          $nodes = array();
          foreach (array_unique($prependedNodes) as $name) {
            $nodes[] = new Twig_Node_SetTemp($name, $node
              ->getLine());
          }
          $nodes[] = $node;
          $node = new Twig_Node($nodes);
        }
      }
    }
    return $node;
  }
  protected function optimizeVariables($node, $env) {
    if ('Twig_Node_Expression_Name' === get_class($node) && $node
      ->isSimple()) {
      $this->prependedNodes[0][] = $node
        ->getAttribute('name');
      return new Twig_Node_Expression_TempName($node
        ->getAttribute('name'), $node
        ->getLine());
    }
    return $node;
  }

  /**
   * Optimizes print nodes.
   *
   * It replaces:
   *
   *   * "echo $this->render(Parent)Block()" with "$this->display(Parent)Block()"
   *
   * @param Twig_NodeInterface $node A Node
   * @param Twig_Environment   $env  The current Twig environment
   */
  protected function optimizePrintNode($node, $env) {
    if (!$node instanceof Twig_Node_Print) {
      return $node;
    }
    if ($node
      ->getNode('expr') instanceof Twig_Node_Expression_BlockReference || $node
      ->getNode('expr') instanceof Twig_Node_Expression_Parent) {
      $node
        ->getNode('expr')
        ->setAttribute('output', true);
      return $node
        ->getNode('expr');
    }
    return $node;
  }

  /**
   * Removes "raw" filters.
   *
   * @param Twig_NodeInterface $node A Node
   * @param Twig_Environment   $env  The current Twig environment
   */
  protected function optimizeRawFilter($node, $env) {
    if ($node instanceof Twig_Node_Expression_Filter && 'raw' == $node
      ->getNode('filter')
      ->getAttribute('value')) {
      return $node
        ->getNode('node');
    }
    return $node;
  }

  /**
   * Optimizes "for" tag by removing the "loop" variable creation whenever possible.
   *
   * @param Twig_NodeInterface $node A Node
   * @param Twig_Environment   $env  The current Twig environment
   */
  protected function enterOptimizeFor($node, $env) {
    if ($node instanceof Twig_Node_For) {

      // disable the loop variable by default
      $node
        ->setAttribute('with_loop', false);
      array_unshift($this->loops, $node);
    }
    elseif (!$this->loops) {

      // we are outside a loop
      return;
    }
    elseif ($node instanceof Twig_Node_Expression_Name && 'loop' === $node
      ->getAttribute('name')) {
      $this
        ->addLoopToCurrent();
    }
    elseif ($node instanceof Twig_Node_BlockReference || $node instanceof Twig_Node_Expression_BlockReference) {
      $this
        ->addLoopToCurrent();
    }
    elseif ($node instanceof Twig_Node_Include && !$node
      ->getAttribute('only')) {
      $this
        ->addLoopToAll();
    }
    elseif ($node instanceof Twig_Node_Expression_GetAttr && (!$node
      ->getNode('attribute') instanceof Twig_Node_Expression_Constant || 'parent' === $node
      ->getNode('attribute')
      ->getAttribute('value')) && (true === $this->loops[0]
      ->getAttribute('with_loop') || $node
      ->getNode('node') instanceof Twig_Node_Expression_Name && 'loop' === $node
      ->getNode('node')
      ->getAttribute('name'))) {
      $this
        ->addLoopToAll();
    }
  }

  /**
   * Optimizes "for" tag by removing the "loop" variable creation whenever possible.
   *
   * @param Twig_NodeInterface $node A Node
   * @param Twig_Environment   $env  The current Twig environment
   */
  protected function leaveOptimizeFor($node, $env) {
    if ($node instanceof Twig_Node_For) {
      array_shift($this->loops);
    }
  }
  protected function addLoopToCurrent() {
    $this->loops[0]
      ->setAttribute('with_loop', true);
  }
  protected function addLoopToAll() {
    foreach ($this->loops as $loop) {
      $loop
        ->setAttribute('with_loop', true);
    }
  }

  /**
   * {@inheritdoc}
   */
  public function getPriority() {
    return 255;
  }

}