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 = $this->optimizePrintNode($node, $env);

    73 

    74         return $node;

    75     }

    76 

    77     /**

    78      * Optimizes print nodes.

    79      *

    80      * It replaces:

    81      *

    82      *   * "echo $this->render(Parent)Block()" with "$this->display(Parent)Block()"

    83      *   * "echo $this->getContext('...')" with "if (isset('...')) { echo '...' }"

    84      *

    85      * @param Twig_NodeInterface $node A Node

    86      * @param Twig_Environment   $env  The current Twig environment

    87      */

    88     protected function optimizePrintNode($node, $env)

    89     {

    90         if (!$node instanceof Twig_Node_Print) {

    91             return $node;

    92         }

    93 

    94         if (

    95             $node->getNode('expr') instanceof Twig_Node_Expression_BlockReference ||

    96             $node->getNode('expr') instanceof Twig_Node_Expression_Parent ||

    97             ($node->getNode('expr') instanceof Twig_Node_Expression_Name && !$env->hasExtension('sandbox') && !$env->isStrictVariables())

    98         ) {

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

   100 

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

   102         }

   103 

   104         return $node;

   105     }

   106 

   107     /**

   108      * Removes "raw" filters.

   109      *

   110      * @param Twig_NodeInterface $node A Node

   111      * @param Twig_Environment   $env  The current Twig environment

   112      */

   113     protected function optimizeRawFilter($node, $env)

   114     {

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

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

   117         }

   118 

   119         return $node;

   120     }

   121 

   122     /**

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

   124      *

   125      * @param Twig_NodeInterface $node A Node

   126      * @param Twig_Environment   $env  The current Twig environment

   127      */

   128     protected function enterOptimizeFor($node, $env)

   129     {

   130         if ($node instanceof Twig_Node_For) {

   131             // disable the loop variable by default

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

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

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

   135             // we are outside a loop

   136             return;

   137         }

   138 

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

   140 

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

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

   143             $this->addLoopToCurrent();

   144         }

   145 

   146         // block reference

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

   148             $this->addLoopToCurrent();

   149         }

   150 

   151         // include without the only attribute

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

   153             $this->addLoopToAll();

   154         }

   155 

   156         // the loop variable is referenced via an attribute

   157         elseif ($node instanceof Twig_Node_Expression_GetAttr

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

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

   160                )

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

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

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

   164                    )

   165                )

   166         ) {

   167             $this->addLoopToAll();

   168         }

   169     }

   170 

   171     /**

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

   173      *

   174      * @param Twig_NodeInterface $node A Node

   175      * @param Twig_Environment   $env  The current Twig environment

   176      */

   177     protected function leaveOptimizeFor($node, $env)

   178     {

   179         if ($node instanceof Twig_Node_For) {

   180             array_shift($this->loops);

   181         }

   182     }

   183 

   184     protected function addLoopToCurrent()

   185     {

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

   187     }

   188 

   189     protected function addLoopToAll()

   190     {

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

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

   193         }

   194     }

   195 

   196     /**

   197      * {@inheritdoc}

   198      */

   199     public function getPriority()

   200     {

   201         return 255;

   202     }

   203 }