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-rw-r--r--inc/Twig/NodeVisitor/Escaper.php167
1 files changed, 167 insertions, 0 deletions
diff --git a/inc/Twig/NodeVisitor/Escaper.php b/inc/Twig/NodeVisitor/Escaper.php
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1<?php
2
3/*
4 * This file is part of Twig.
5 *
6 * (c) 2009 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_Escaper implements output escaping.
14 *
15 * @author Fabien Potencier <fabien@symfony.com>
16 */
17class Twig_NodeVisitor_Escaper implements Twig_NodeVisitorInterface
18{
19 protected $statusStack = array();
20 protected $blocks = array();
21 protected $safeAnalysis;
22 protected $traverser;
23 protected $defaultStrategy = false;
24 protected $safeVars = array();
25
26 public function __construct()
27 {
28 $this->safeAnalysis = new Twig_NodeVisitor_SafeAnalysis();
29 }
30
31 /**
32 * Called before child nodes are visited.
33 *
34 * @param Twig_NodeInterface $node The node to visit
35 * @param Twig_Environment $env The Twig environment instance
36 *
37 * @return Twig_NodeInterface The modified node
38 */
39 public function enterNode(Twig_NodeInterface $node, Twig_Environment $env)
40 {
41 if ($node instanceof Twig_Node_Module) {
42 if ($env->hasExtension('escaper') && $defaultStrategy = $env->getExtension('escaper')->getDefaultStrategy($node->getAttribute('filename'))) {
43 $this->defaultStrategy = $defaultStrategy;
44 }
45 $this->safeVars = array();
46 } elseif ($node instanceof Twig_Node_AutoEscape) {
47 $this->statusStack[] = $node->getAttribute('value');
48 } elseif ($node instanceof Twig_Node_Block) {
49 $this->statusStack[] = isset($this->blocks[$node->getAttribute('name')]) ? $this->blocks[$node->getAttribute('name')] : $this->needEscaping($env);
50 } elseif ($node instanceof Twig_Node_Import) {
51 $this->safeVars[] = $node->getNode('var')->getAttribute('name');
52 }
53
54 return $node;
55 }
56
57 /**
58 * Called after child nodes are visited.
59 *
60 * @param Twig_NodeInterface $node The node to visit
61 * @param Twig_Environment $env The Twig environment instance
62 *
63 * @return Twig_NodeInterface The modified node
64 */
65 public function leaveNode(Twig_NodeInterface $node, Twig_Environment $env)
66 {
67 if ($node instanceof Twig_Node_Module) {
68 $this->defaultStrategy = false;
69 $this->safeVars = array();
70 } elseif ($node instanceof Twig_Node_Expression_Filter) {
71 return $this->preEscapeFilterNode($node, $env);
72 } elseif ($node instanceof Twig_Node_Print) {
73 return $this->escapePrintNode($node, $env, $this->needEscaping($env));
74 }
75
76 if ($node instanceof Twig_Node_AutoEscape || $node instanceof Twig_Node_Block) {
77 array_pop($this->statusStack);
78 } elseif ($node instanceof Twig_Node_BlockReference) {
79 $this->blocks[$node->getAttribute('name')] = $this->needEscaping($env);
80 }
81
82 return $node;
83 }
84
85 protected function escapePrintNode(Twig_Node_Print $node, Twig_Environment $env, $type)
86 {
87 if (false === $type) {
88 return $node;
89 }
90
91 $expression = $node->getNode('expr');
92
93 if ($this->isSafeFor($type, $expression, $env)) {
94 return $node;
95 }
96
97 $class = get_class($node);
98
99 return new $class(
100 $this->getEscaperFilter($type, $expression),
101 $node->getLine()
102 );
103 }
104
105 protected function preEscapeFilterNode(Twig_Node_Expression_Filter $filter, Twig_Environment $env)
106 {
107 $name = $filter->getNode('filter')->getAttribute('value');
108
109 $type = $env->getFilter($name)->getPreEscape();
110 if (null === $type) {
111 return $filter;
112 }
113
114 $node = $filter->getNode('node');
115 if ($this->isSafeFor($type, $node, $env)) {
116 return $filter;
117 }
118
119 $filter->setNode('node', $this->getEscaperFilter($type, $node));
120
121 return $filter;
122 }
123
124 protected function isSafeFor($type, Twig_NodeInterface $expression, $env)
125 {
126 $safe = $this->safeAnalysis->getSafe($expression);
127
128 if (null === $safe) {
129 if (null === $this->traverser) {
130 $this->traverser = new Twig_NodeTraverser($env, array($this->safeAnalysis));
131 }
132
133 $this->safeAnalysis->setSafeVars($this->safeVars);
134
135 $this->traverser->traverse($expression);
136 $safe = $this->safeAnalysis->getSafe($expression);
137 }
138
139 return in_array($type, $safe) || in_array('all', $safe);
140 }
141
142 protected function needEscaping(Twig_Environment $env)
143 {
144 if (count($this->statusStack)) {
145 return $this->statusStack[count($this->statusStack) - 1];
146 }
147
148 return $this->defaultStrategy ? $this->defaultStrategy : false;
149 }
150
151 protected function getEscaperFilter($type, Twig_NodeInterface $node)
152 {
153 $line = $node->getLine();
154 $name = new Twig_Node_Expression_Constant('escape', $line);
155 $args = new Twig_Node(array(new Twig_Node_Expression_Constant((string) $type, $line), new Twig_Node_Expression_Constant(null, $line), new Twig_Node_Expression_Constant(true, $line)));
156
157 return new Twig_Node_Expression_Filter($node, $name, $args, $line);
158 }
159
160 /**
161 * {@inheritdoc}
162 */
163 public function getPriority()
164 {
165 return 0;
166 }
167}