1 <?php

     2 

     3 /*

     4  * This file is part of Twig.

     5  *

     6  * (c) 2009 Fabien Potencier

     7  *

     8  * For the full copyright and license information, please view the LICENSE

     9  * file that was distributed with this source code.

    10  */

    11 

    12 /**

    13  * Twig_NodeTraverser is a node traverser.

    14  *

    15  * It visits all nodes and their children and call the given visitor for each.

    16  *

    17  * @package    twig

    18  * @author     Fabien Potencier <fabien@symfony.com>

    19  */

    20 class Twig_NodeTraverser

    21 {

    22     protected $env;

    23     protected $visitors;

    24 

    25     /**

    26      * Constructor.

    27      *

    28      * @param Twig_Environment $env      A Twig_Environment instance

    29      * @param array            $visitors An array of Twig_NodeVisitorInterface instances

    30      */

    31     public function __construct(Twig_Environment $env, array $visitors = array())

    32     {

    33         $this->env = $env;

    34         $this->visitors = array();

    35         foreach ($visitors as $visitor) {

    36             $this->addVisitor($visitor);

    37         }

    38     }

    39 

    40     /**

    41      * Adds a visitor.

    42      *

    43      * @param Twig_NodeVisitorInterface $visitor A Twig_NodeVisitorInterface instance

    44      */

    45     public function addVisitor(Twig_NodeVisitorInterface $visitor)

    46     {

    47         if (!isset($this->visitors[$visitor->getPriority()])) {

    48             $this->visitors[$visitor->getPriority()] = array();

    49         }

    50 

    51         $this->visitors[$visitor->getPriority()][] = $visitor;

    52     }

    53 

    54     /**

    55      * Traverses a node and calls the registered visitors.

    56      *

    57      * @param Twig_NodeInterface $node A Twig_NodeInterface instance

    58      */

    59     public function traverse(Twig_NodeInterface $node)

    60     {

    61         ksort($this->visitors);

    62         foreach ($this->visitors as $visitors) {

    63             foreach ($visitors as $visitor) {

    64                 $node = $this->traverseForVisitor($visitor, $node);

    65             }

    66         }

    67 

    68         return $node;

    69     }

    70 

    71     protected function traverseForVisitor(Twig_NodeVisitorInterface $visitor, Twig_NodeInterface $node = null)

    72     {

    73         if (null === $node) {

    74             return null;

    75         }

    76 

    77         $node = $visitor->enterNode($node, $this->env);

    78 

    79         foreach ($node as $k => $n) {

    80             if (false !== $n = $this->traverseForVisitor($visitor, $n)) {

    81                 $node->setNode($k, $n);

    82             } else {

    83                 $node->removeNode($k);

    84             }

    85         }

    86 

    87         return $visitor->leaveNode($node, $this->env);

    88     }

    89 }