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<?php
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class Twig_NodeVisitor_SafeAnalysis implements Twig_NodeVisitorInterface
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{
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protected $data = array();
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protected $safeVars = array();
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public function setSafeVars($safeVars)
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{
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$this->safeVars = $safeVars;
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}
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public function getSafe(Twig_NodeInterface $node)
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{
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$hash = spl_object_hash($node);
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if (isset($this->data[$hash])) {
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foreach ($this->data[$hash] as $bucket) {
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if ($bucket['key'] === $node) {
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return $bucket['value'];
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}
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}
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}
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return null;
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}
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protected function setSafe(Twig_NodeInterface $node, array $safe)
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{
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$hash = spl_object_hash($node);
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if (isset($this->data[$hash])) {
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foreach ($this->data[$hash] as &$bucket) {
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if ($bucket['key'] === $node) {
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$bucket['value'] = $safe;
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return;
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}
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}
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}
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$this->data[$hash][] = array(
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'key' => $node,
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'value' => $safe,
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);
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}
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public function enterNode(Twig_NodeInterface $node, Twig_Environment $env)
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{
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return $node;
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}
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public function leaveNode(Twig_NodeInterface $node, Twig_Environment $env)
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{
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if ($node instanceof Twig_Node_Expression_Constant) {
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// constants are marked safe for all
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$this->setSafe($node, array('all'));
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} elseif ($node instanceof Twig_Node_Expression_BlockReference) {
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// blocks are safe by definition
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$this->setSafe($node, array('all'));
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} elseif ($node instanceof Twig_Node_Expression_Parent) {
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// parent block is safe by definition
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$this->setSafe($node, array('all'));
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} elseif ($node instanceof Twig_Node_Expression_Conditional) {
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// intersect safeness of both operands
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$safe = $this->intersectSafe($this->getSafe($node->getNode('expr2')), $this->getSafe($node->getNode('expr3')));
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$this->setSafe($node, $safe);
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} elseif ($node instanceof Twig_Node_Expression_Filter) {
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// filter expression is safe when the filter is safe
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$name = $node->getNode('filter')->getAttribute('value');
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$args = $node->getNode('arguments');
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if (false !== $filter = $env->getFilter($name)) {
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$safe = $filter->getSafe($args);
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if (null === $safe) {
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$safe = $this->intersectSafe($this->getSafe($node->getNode('node')), $filter->getPreservesSafety());
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}
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$this->setSafe($node, $safe);
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} else {
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$this->setSafe($node, array());
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}
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} elseif ($node instanceof Twig_Node_Expression_Function) {
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// function expression is safe when the function is safe
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$name = $node->getAttribute('name');
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$args = $node->getNode('arguments');
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$function = $env->getFunction($name);
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if (false !== $function) {
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$this->setSafe($node, $function->getSafe($args));
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} else {
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$this->setSafe($node, array());
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}
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} elseif ($node instanceof Twig_Node_Expression_MethodCall) {
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if ($node->getAttribute('safe')) {
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$this->setSafe($node, array('all'));
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} else {
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$this->setSafe($node, array());
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}
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} elseif ($node instanceof Twig_Node_Expression_GetAttr && $node->getNode('node') instanceof Twig_Node_Expression_Name) {
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$name = $node->getNode('node')->getAttribute('name');
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// attributes on template instances are safe
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if ('_self' == $name || in_array($name, $this->safeVars)) {
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$this->setSafe($node, array('all'));
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} else {
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$this->setSafe($node, array());
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}
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} else {
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$this->setSafe($node, array());
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}
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return $node;
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}
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protected function intersectSafe(array $a = null, array $b = null)
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{
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if (null === $a || null === $b) {
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return array();
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}
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if (in_array('all', $a)) {
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return $b;
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}
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if (in_array('all', $b)) {
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return $a;
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}
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return array_intersect($a, $b);
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}
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/**
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* {@inheritdoc}
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*/
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public function getPriority()
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{
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return 0;
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}
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}
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