vendor/twig/twig/lib/Twig/NodeVisitor/Optimizer.php

   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  * @author Fabien Potencier <fabien@symfony.com>
  21  */
  22 class Twig_NodeVisitor_Optimizer implements Twig_NodeVisitorInterface
  23 {
  24     const OPTIMIZE_ALL         = -1;
  25     const OPTIMIZE_NONE        = 0;
  26     const OPTIMIZE_FOR         = 2;
  27     const OPTIMIZE_RAW_FILTER  = 4;
  28     const OPTIMIZE_VAR_ACCESS  = 8;
  29
  30     protected $loops = array();
  31     protected $optimizers;
  32     protected $prependedNodes = array();
  33     protected $inABody = false;
  34
  35     /**
  36      * Constructor.
  37      *
  38      * @param integer $optimizers The optimizer mode
  39      */
  40     public function __construct($optimizers = -1)
  41     {
  42         if (!is_int($optimizers) || $optimizers > 2) {
  43             throw new InvalidArgumentException(sprintf('Optimizer mode "%s" is not valid.', $optimizers));
  44         }
  45
  46         $this->optimizers = $optimizers;
  47     }
  48
  49     /**
  50      * {@inheritdoc}
  51      */
  52     public function enterNode(Twig_NodeInterface $node, Twig_Environment $env)
  53     {
  54         if (self::OPTIMIZE_FOR === (self::OPTIMIZE_FOR & $this->optimizers)) {
  55             $this->enterOptimizeFor($node, $env);
  56         }
  57
  58         if (!version_compare(phpversion(), '5.4.0RC1', '>=') && self::OPTIMIZE_VAR_ACCESS === (self::OPTIMIZE_VAR_ACCESS & $this->optimizers) && !$env->isStrictVariables() && !$env->hasExtension('sandbox')) {
  59             if ($this->inABody) {
  60                 if (!$node instanceof Twig_Node_Expression) {
  61                     if (get_class($node) !== 'Twig_Node') {
  62                         array_unshift($this->prependedNodes, array());
  63                     }
  64                 } else {
  65                     $node = $this->optimizeVariables($node, $env);
  66                 }
  67             } elseif ($node instanceof Twig_Node_Body) {
  68                 $this->inABody = true;
  69             }
  70         }
  71
  72         return $node;
  73     }
  74
  75     /**
  76      * {@inheritdoc}
  77      */
  78     public function leaveNode(Twig_NodeInterface $node, Twig_Environment $env)
  79     {
  80         $expression = $node instanceof Twig_Node_Expression;
  81
  82         if (self::OPTIMIZE_FOR === (self::OPTIMIZE_FOR & $this->optimizers)) {
  83             $this->leaveOptimizeFor($node, $env);
  84         }
  85
  86         if (self::OPTIMIZE_RAW_FILTER === (self::OPTIMIZE_RAW_FILTER & $this->optimizers)) {
  87             $node = $this->optimizeRawFilter($node, $env);
  88         }
  89
  90         $node = $this->optimizePrintNode($node, $env);
  91
  92         if (self::OPTIMIZE_VAR_ACCESS === (self::OPTIMIZE_VAR_ACCESS & $this->optimizers) && !$env->isStrictVariables() && !$env->hasExtension('sandbox')) {
  93             if ($node instanceof Twig_Node_Body) {
  94                 $this->inABody = false;
  95             } elseif ($this->inABody) {
  96                 if (!$expression && get_class($node) !== 'Twig_Node' && $prependedNodes = array_shift($this->prependedNodes)) {
  97                     $nodes = array();
  98                     foreach (array_unique($prependedNodes) as $name) {
  99                         $nodes[] = new Twig_Node_SetTemp($name, $node->getLine());
 100                     }
 101
 102                     $nodes[] = $node;
 103                     $node = new Twig_Node($nodes);
 104                 }
 105             }
 106         }
 107
 108         return $node;
 109     }
 110
 111     protected function optimizeVariables($node, $env)
 112     {
 113         if ('Twig_Node_Expression_Name' === get_class($node) && $node->isSimple()) {
 114             $this->prependedNodes[0][] = $node->getAttribute('name');
 115
 116             return new Twig_Node_Expression_TempName($node->getAttribute('name'), $node->getLine());
 117         }
 118
 119         return $node;
 120     }
 121
 122     /**
 123      * Optimizes print nodes.
 124      *
 125      * It replaces:
 126      *
 127      *   * "echo $this->render(Parent)Block()" with "$this->display(Parent)Block()"
 128      *
 129      * @param Twig_NodeInterface $node A Node
 130      * @param Twig_Environment   $env  The current Twig environment
 131      */
 132     protected function optimizePrintNode($node, $env)
 133     {
 134         if (!$node instanceof Twig_Node_Print) {
 135             return $node;
 136         }
 137
 138         if (
 139             $node->getNode('expr') instanceof Twig_Node_Expression_BlockReference ||
 140             $node->getNode('expr') instanceof Twig_Node_Expression_Parent
 141         ) {
 142             $node->getNode('expr')->setAttribute('output', true);
 143
 144             return $node->getNode('expr');
 145         }
 146
 147         return $node;
 148     }
 149
 150     /**
 151      * Removes "raw" filters.
 152      *
 153      * @param Twig_NodeInterface $node A Node
 154      * @param Twig_Environment   $env  The current Twig environment
 155      */
 156     protected function optimizeRawFilter($node, $env)
 157     {
 158         if ($node instanceof Twig_Node_Expression_Filter && 'raw' == $node->getNode('filter')->getAttribute('value')) {
 159             return $node->getNode('node');
 160         }
 161
 162         return $node;
 163     }
 164
 165     /**
 166      * Optimizes "for" tag by removing the "loop" variable creation whenever possible.
 167      *
 168      * @param Twig_NodeInterface $node A Node
 169      * @param Twig_Environment   $env  The current Twig environment
 170      */
 171     protected function enterOptimizeFor($node, $env)
 172     {
 173         if ($node instanceof Twig_Node_For) {
 174             // disable the loop variable by default
 175             $node->setAttribute('with_loop', false);
 176             array_unshift($this->loops, $node);
 177         } elseif (!$this->loops) {
 178             // we are outside a loop
 179             return;
 180         }
 181
 182         // when do we need to add the loop variable back?
 183
 184         // the loop variable is referenced for the current loop
 185         elseif ($node instanceof Twig_Node_Expression_Name && 'loop' === $node->getAttribute('name')) {
 186             $this->addLoopToCurrent();
 187         }
 188
 189         // block reference
 190         elseif ($node instanceof Twig_Node_BlockReference || $node instanceof Twig_Node_Expression_BlockReference) {
 191             $this->addLoopToCurrent();
 192         }
 193
 194         // include without the only attribute
 195         elseif ($node instanceof Twig_Node_Include && !$node->getAttribute('only')) {
 196             $this->addLoopToAll();
 197         }
 198
 199         // the loop variable is referenced via an attribute
 200         elseif ($node instanceof Twig_Node_Expression_GetAttr
 201             && (!$node->getNode('attribute') instanceof Twig_Node_Expression_Constant
 202                 || 'parent' === $node->getNode('attribute')->getAttribute('value')
 203                )
 204             && (true === $this->loops[0]->getAttribute('with_loop')
 205                 || ($node->getNode('node') instanceof Twig_Node_Expression_Name
 206                     && 'loop' === $node->getNode('node')->getAttribute('name')
 207                    )
 208                )
 209         ) {
 210             $this->addLoopToAll();
 211         }
 212     }
 213
 214     /**
 215      * Optimizes "for" tag by removing the "loop" variable creation whenever possible.
 216      *
 217      * @param Twig_NodeInterface $node A Node
 218      * @param Twig_Environment   $env  The current Twig environment
 219      */
 220     protected function leaveOptimizeFor($node, $env)
 221     {
 222         if ($node instanceof Twig_Node_For) {
 223             array_shift($this->loops);
 224         }
 225     }
 226
 227     protected function addLoopToCurrent()
 228     {
 229         $this->loops[0]->setAttribute('with_loop', true);
 230     }
 231
 232     protected function addLoopToAll()
 233     {
 234         foreach ($this->loops as $loop) {
 235             $loop->setAttribute('with_loop', true);
 236         }
 237     }
 238
 239     /**
 240      * {@inheritdoc}
 241      */
 242     public function getPriority()
 243     {
 244         return 255;
 245     }
 246 }