Complex classes like Twig_NodeVisitor_Optimizer often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes. You can also have a look at the cohesion graph to spot any un-connected, or weakly-connected components.
Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.
While breaking up the class, it is a good idea to analyze how other classes use Twig_NodeVisitor_Optimizer, and based on these observations, apply Extract Interface, too.
| 1 | <?php |
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| 22 | class Twig_NodeVisitor_Optimizer implements Twig_NodeVisitorInterface |
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| 23 | { |
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| 24 | const OPTIMIZE_ALL = -1; |
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| 25 | const OPTIMIZE_NONE = 0; |
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| 26 | const OPTIMIZE_FOR = 2; |
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| 27 | const OPTIMIZE_RAW_FILTER = 4; |
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| 28 | const OPTIMIZE_VAR_ACCESS = 8; |
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| 29 | |||
| 30 | protected $loops = array(); |
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| 31 | protected $loopsTargets = array(); |
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| 32 | protected $optimizers; |
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| 33 | protected $prependedNodes = array(); |
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| 34 | protected $inABody = false; |
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| 35 | |||
| 36 | /** |
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| 37 | * Constructor. |
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| 38 | * |
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| 39 | * @param int $optimizers The optimizer mode |
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| 40 | */ |
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| 41 | public function __construct($optimizers = -1) |
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| 42 | { |
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| 43 | if (!is_int($optimizers) || $optimizers > (self::OPTIMIZE_FOR | self::OPTIMIZE_RAW_FILTER | self::OPTIMIZE_VAR_ACCESS)) { |
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| 44 | throw new InvalidArgumentException(sprintf('Optimizer mode "%s" is not valid.', $optimizers)); |
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| 45 | } |
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| 46 | |||
| 47 | $this->optimizers = $optimizers; |
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| 48 | } |
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| 49 | |||
| 50 | /** |
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| 51 | * {@inheritdoc} |
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| 52 | */ |
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| 53 | public function enterNode(Twig_NodeInterface $node, Twig_Environment $env) |
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| 54 | { |
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| 55 | if (self::OPTIMIZE_FOR === (self::OPTIMIZE_FOR & $this->optimizers)) { |
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| 56 | $this->enterOptimizeFor($node, $env); |
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| 57 | } |
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| 58 | |||
| 59 | if (!version_compare(phpversion(), '5.4.0RC1', '>=') && self::OPTIMIZE_VAR_ACCESS === (self::OPTIMIZE_VAR_ACCESS & $this->optimizers) && !$env->isStrictVariables() && !$env->hasExtension('sandbox')) { |
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| 60 | if ($this->inABody) { |
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| 61 | if (!$node instanceof Twig_Node_Expression) { |
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| 62 | if (get_class($node) !== 'Twig_Node') { |
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| 63 | array_unshift($this->prependedNodes, array()); |
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| 64 | } |
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| 65 | } else { |
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| 66 | $node = $this->optimizeVariables($node, $env); |
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| 67 | } |
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| 68 | } elseif ($node instanceof Twig_Node_Body) { |
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| 69 | $this->inABody = true; |
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| 70 | } |
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| 71 | } |
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| 72 | |||
| 73 | return $node; |
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| 74 | } |
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| 75 | |||
| 76 | /** |
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| 77 | * {@inheritdoc} |
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| 78 | */ |
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| 79 | public function leaveNode(Twig_NodeInterface $node, Twig_Environment $env) |
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| 80 | { |
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| 81 | $expression = $node instanceof Twig_Node_Expression; |
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| 82 | |||
| 83 | if (self::OPTIMIZE_FOR === (self::OPTIMIZE_FOR & $this->optimizers)) { |
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| 84 | $this->leaveOptimizeFor($node, $env); |
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| 85 | } |
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| 86 | |||
| 87 | if (self::OPTIMIZE_RAW_FILTER === (self::OPTIMIZE_RAW_FILTER & $this->optimizers)) { |
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| 88 | $node = $this->optimizeRawFilter($node, $env); |
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| 89 | } |
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| 90 | |||
| 91 | $node = $this->optimizePrintNode($node, $env); |
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| 92 | |||
| 93 | if (self::OPTIMIZE_VAR_ACCESS === (self::OPTIMIZE_VAR_ACCESS & $this->optimizers) && !$env->isStrictVariables() && !$env->hasExtension('sandbox')) { |
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| 94 | if ($node instanceof Twig_Node_Body) { |
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| 95 | $this->inABody = false; |
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| 96 | } elseif ($this->inABody) { |
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| 97 | if (!$expression && get_class($node) !== 'Twig_Node' && $prependedNodes = array_shift($this->prependedNodes)) { |
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| 98 | $nodes = array(); |
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| 99 | foreach (array_unique($prependedNodes) as $name) { |
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| 100 | $nodes[] = new Twig_Node_SetTemp($name, $node->getLine()); |
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| 101 | } |
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| 102 | |||
| 103 | $nodes[] = $node; |
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| 104 | $node = new Twig_Node($nodes); |
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| 105 | } |
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| 106 | } |
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| 107 | } |
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| 108 | |||
| 109 | return $node; |
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| 110 | } |
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| 111 | |||
| 112 | protected function optimizeVariables(Twig_NodeInterface $node, Twig_Environment $env) |
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| 113 | { |
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| 114 | if ('Twig_Node_Expression_Name' === get_class($node) && $node->isSimple()) { |
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| 115 | $this->prependedNodes[0][] = $node->getAttribute('name'); |
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| 116 | |||
| 117 | return new Twig_Node_Expression_TempName($node->getAttribute('name'), $node->getLine()); |
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| 118 | } |
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| 119 | |||
| 120 | return $node; |
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| 121 | } |
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| 122 | |||
| 123 | /** |
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| 124 | * Optimizes print nodes. |
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| 125 | * |
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| 126 | * It replaces: |
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| 127 | * |
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| 128 | * * "echo $this->render(Parent)Block()" with "$this->display(Parent)Block()" |
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| 129 | * |
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| 130 | * @param Twig_NodeInterface $node A Node |
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| 131 | * @param Twig_Environment $env The current Twig environment |
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| 132 | */ |
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| 133 | protected function optimizePrintNode(Twig_NodeInterface $node, Twig_Environment $env) |
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| 150 | |||
| 151 | /** |
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| 152 | * Removes "raw" filters. |
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| 153 | * |
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| 154 | * @param Twig_NodeInterface $node A Node |
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| 155 | * @param Twig_Environment $env The current Twig environment |
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| 156 | */ |
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| 157 | protected function optimizeRawFilter(Twig_NodeInterface $node, Twig_Environment $env) |
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| 158 | { |
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| 159 | if ($node instanceof Twig_Node_Expression_Filter && 'raw' == $node->getNode('filter')->getAttribute('value')) { |
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| 160 | return $node->getNode('node'); |
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| 161 | } |
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| 162 | |||
| 163 | return $node; |
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| 164 | } |
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| 165 | |||
| 166 | /** |
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| 167 | * Optimizes "for" tag by removing the "loop" variable creation whenever possible. |
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| 168 | * |
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| 169 | * @param Twig_NodeInterface $node A Node |
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| 170 | * @param Twig_Environment $env The current Twig environment |
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| 171 | */ |
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| 172 | protected function enterOptimizeFor(Twig_NodeInterface $node, Twig_Environment $env) |
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| 173 | { |
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| 174 | if ($node instanceof Twig_Node_For) { |
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| 175 | // disable the loop variable by default |
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| 176 | $node->setAttribute('with_loop', false); |
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| 177 | array_unshift($this->loops, $node); |
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| 178 | array_unshift($this->loopsTargets, $node->getNode('value_target')->getAttribute('name')); |
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| 179 | array_unshift($this->loopsTargets, $node->getNode('key_target')->getAttribute('name')); |
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| 180 | } elseif (!$this->loops) { |
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| 181 | // we are outside a loop |
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| 182 | return; |
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| 183 | } |
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| 184 | |||
| 185 | // when do we need to add the loop variable back? |
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| 186 | |||
| 187 | // the loop variable is referenced for the current loop |
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| 188 | elseif ($node instanceof Twig_Node_Expression_Name && 'loop' === $node->getAttribute('name')) { |
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| 189 | $node->setAttribute('always_defined', true); |
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| 190 | $this->addLoopToCurrent(); |
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| 191 | } |
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| 192 | |||
| 193 | // optimize access to loop targets |
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| 194 | elseif ($node instanceof Twig_Node_Expression_Name && in_array($node->getAttribute('name'), $this->loopsTargets)) { |
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| 195 | $node->setAttribute('always_defined', true); |
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| 196 | } |
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| 197 | |||
| 198 | // block reference |
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| 199 | elseif ($node instanceof Twig_Node_BlockReference || $node instanceof Twig_Node_Expression_BlockReference) { |
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| 200 | $this->addLoopToCurrent(); |
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| 201 | } |
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| 202 | |||
| 203 | // include without the only attribute |
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| 204 | elseif ($node instanceof Twig_Node_Include && !$node->getAttribute('only')) { |
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| 205 | $this->addLoopToAll(); |
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| 206 | } |
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| 207 | |||
| 208 | // include function without the with_context=false parameter |
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| 209 | elseif ($node instanceof Twig_Node_Expression_Function |
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| 210 | && 'include' === $node->getAttribute('name') |
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| 211 | && (!$node->getNode('arguments')->hasNode('with_context') |
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| 212 | || false !== $node->getNode('arguments')->getNode('with_context')->getAttribute('value') |
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| 213 | ) |
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| 214 | ) { |
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| 215 | $this->addLoopToAll(); |
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| 216 | } |
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| 217 | |||
| 218 | // the loop variable is referenced via an attribute |
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| 219 | elseif ($node instanceof Twig_Node_Expression_GetAttr |
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| 220 | && (!$node->getNode('attribute') instanceof Twig_Node_Expression_Constant |
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| 221 | || 'parent' === $node->getNode('attribute')->getAttribute('value') |
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| 222 | ) |
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| 223 | && (true === $this->loops[0]->getAttribute('with_loop') |
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| 224 | || ($node->getNode('node') instanceof Twig_Node_Expression_Name |
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| 225 | && 'loop' === $node->getNode('node')->getAttribute('name') |
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| 226 | ) |
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| 227 | ) |
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| 228 | ) { |
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| 229 | $this->addLoopToAll(); |
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| 230 | } |
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| 231 | } |
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| 232 | |||
| 233 | /** |
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| 234 | * Optimizes "for" tag by removing the "loop" variable creation whenever possible. |
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| 235 | * |
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| 236 | * @param Twig_NodeInterface $node A Node |
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| 237 | * @param Twig_Environment $env The current Twig environment |
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| 238 | */ |
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| 239 | protected function leaveOptimizeFor(Twig_NodeInterface $node, Twig_Environment $env) |
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| 240 | { |
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| 241 | if ($node instanceof Twig_Node_For) { |
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| 242 | array_shift($this->loops); |
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| 243 | array_shift($this->loopsTargets); |
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| 244 | array_shift($this->loopsTargets); |
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| 245 | } |
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| 246 | } |
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| 247 | |||
| 248 | protected function addLoopToCurrent() |
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| 252 | |||
| 253 | protected function addLoopToAll() |
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| 254 | { |
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| 255 | foreach ($this->loops as $loop) { |
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| 256 | $loop->setAttribute('with_loop', true); |
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| 257 | } |
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| 258 | } |
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| 259 | |||
| 260 | /** |
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| 261 | * {@inheritdoc} |
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| 262 | */ |
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| 263 | public function getPriority() |
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| 267 | } |
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| 268 |
This check looks from parameters that have been defined for a function or method, but which are not used in the method body.