1 <?php

     2 

     3 /*

     4  * This file is part of Twig.

     5  *

     6  * (c) 2010 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_NodeVisitor_Optimizer tries to optimizes the AST.

    14  *

    15  * This visitor is always the last registered one.

    16  *

    17  * You can configure which optimizations you want to activate via the

    18  * optimizer mode.

    19  *

    20  * @package twig

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

    22  */

    23 class Twig_NodeVisitor_Optimizer implements Twig_NodeVisitorInterface

    24 {

    25     const OPTIMIZE_ALL         = -1;

    26     const OPTIMIZE_NONE        = 0;

    27     const OPTIMIZE_FOR         = 2;

    28     const OPTIMIZE_RAW_FILTER  = 4;

    29 

    30     protected $loops = array();

    31     protected $optimizers;

    32 

    33     /**

    34      * Constructor.

    35      *

    36      * @param integer $optimizers The optimizer mode

    37      */

    38     public function __construct($optimizers = -1)

    39     {

    40         if (!is_int($optimizers) || $optimizers > 2) {

    41             throw new InvalidArgumentException(sprintf('Optimizer mode "%s" is not valid.', $optimizers));

    42         }

    43 

    44         $this->optimizers = $optimizers;

    45     }

    46 

    47     /**

    48      * {@inheritdoc}

    49      */

    50     public function enterNode(Twig_NodeInterface $node, Twig_Environment $env)

    51     {

    52         if (self::OPTIMIZE_FOR === (self::OPTIMIZE_FOR & $this->optimizers)) {

    53             $this->enterOptimizeFor($node, $env);

    54         }

    55 

    56         return $node;

    57     }

    58 

    59     /**

    60      * {@inheritdoc}

    61      */

    62     public function leaveNode(Twig_NodeInterface $node, Twig_Environment $env)

    63     {

    64         if (self::OPTIMIZE_FOR === (self::OPTIMIZE_FOR & $this->optimizers)) {

    65             $this->leaveOptimizeFor($node, $env);

    66         }

    67 

    68         if (self::OPTIMIZE_RAW_FILTER === (self::OPTIMIZE_RAW_FILTER & $this->optimizers)) {

    69             $node = $this->optimizeRawFilter($node, $env);

    70         }

    71 

    72         $node = $this->optimizeRenderBlock($node, $env);

    73 

    74         return $node;

    75     }

    76 

    77     /**

    78      * Replaces "echo $this->renderBlock()" with "$this->displayBlock()".

    79      *

    80      * @param Twig_NodeInterface $node A Node

    81      * @param Twig_Environment   $env  The current Twig environment

    82      */

    83     protected function optimizeRenderBlock($node, $env)

    84     {

    85         if ($node instanceof Twig_Node_Print && $node->getNode('expr') instanceof Twig_Node_Expression_BlockReference) {

    86             $node->getNode('expr')->setAttribute('output', true);

    87 

    88             return $node->getNode('expr');

    89         }

    90 

    91         return $node;

    92     }

    93 

    94     /**

    95      * Removes "raw" filters.

    96      *

    97      * @param Twig_NodeInterface $node A Node

    98      * @param Twig_Environment   $env  The current Twig environment

    99      */

   100     protected function optimizeRawFilter($node, $env)

   101     {

   102         if ($node instanceof Twig_Node_Expression_Filter && 'raw' == $node->getNode('filter')->getAttribute('value')) {

   103             return $node->getNode('node');

   104         }

   105 

   106         return $node;

   107     }

   108 

   109     /**

   110      * Optimizes "for" tag by removing the "loop" variable creation whenever possible.

   111      *

   112      * @param Twig_NodeInterface $node A Node

   113      * @param Twig_Environment   $env  The current Twig environment

   114      */

   115     protected function enterOptimizeFor($node, $env)

   116     {

   117         if ($node instanceof Twig_Node_For) {

   118             // disable the loop variable by default

   119             $node->setAttribute('with_loop', false);

   120             array_unshift($this->loops, $node);

   121         } elseif (!$this->loops) {

   122             // we are outside a loop

   123             return;

   124         }

   125 

   126         // when do we need to add the loop variable back?

   127 

   128         // the loop variable is referenced for the current loop

   129         elseif ($node instanceof Twig_Node_Expression_Name && 'loop' === $node->getAttribute('name')) {

   130             $this->addLoopToCurrent();

   131         }

   132 

   133         // block reference

   134         elseif ($node instanceof Twig_Node_BlockReference || $node instanceof Twig_Node_Expression_BlockReference) {

   135             $this->addLoopToCurrent();

   136         }

   137 

   138         // include without the only attribute

   139         elseif ($node instanceof Twig_Node_Include && !$node->getAttribute('only')) {

   140             $this->addLoopToAll();

   141         }

   142 

   143         // the loop variable is referenced via an attribute

   144         elseif ($node instanceof Twig_Node_Expression_GetAttr

   145             && (!$node->getNode('attribute') instanceof Twig_Node_Expression_Constant

   146                 || 'parent' === $node->getNode('attribute')->getAttribute('value')

   147                )

   148             && (true === $this->loops[0]->getAttribute('with_loop')

   149                 || ($node->getNode('node') instanceof Twig_Node_Expression_Name

   150                     && 'loop' === $node->getNode('node')->getAttribute('name')

   151                    )

   152                )

   153         ) {

   154             $this->addLoopToAll();

   155         }

   156     }

   157 

   158     /**

   159      * Optimizes "for" tag by removing the "loop" variable creation whenever possible.

   160      *

   161      * @param Twig_NodeInterface $node A Node

   162      * @param Twig_Environment   $env  The current Twig environment

   163      */

   164     protected function leaveOptimizeFor($node, $env)

   165     {

   166         if ($node instanceof Twig_Node_For) {

   167             array_shift($this->loops);

   168         }

   169     }

   170 

   171     protected function addLoopToCurrent()

   172     {

   173         $this->loops[0]->setAttribute('with_loop', true);

   174     }

   175 

   176     protected function addLoopToAll()

   177     {

   178         foreach ($this->loops as $loop) {

   179             $loop->setAttribute('with_loop', true);

   180         }

   181     }

   182 

   183     /**

   184      * {@inheritdoc}

   185      */

   186     public function getPriority()

   187     {

   188         return 255;

   189     }

   190 }