File indexing completed on 2024-05-12 06:02:04

 <?php
 
 /**
  * Validates the HTML attribute style, otherwise known as CSS.
  * @note We don't implement the whole CSS specification, so it might be
  *       difficult to reuse this component in the context of validating
  *       actual stylesheet declarations.
  * @note If we were really serious about validating the CSS, we would
  *       tokenize the styles and then parse the tokens. Obviously, we
  *       are not doing that. Doing that could seriously harm performance,
  *       but would make these components a lot more viable for a CSS
  *       filtering solution.
  */
 class HTMLPurifier_AttrDef_CSS extends HTMLPurifier_AttrDef
 {
 
     /**
      * @param string $css
      * @param HTMLPurifier_Config $config
      * @param HTMLPurifier_Context $context
      * @return bool|string
      */
     public function validate($css, $config, $context)
     {
         $css = $this->parseCDATA($css);
 
         $definition = $config->getCSSDefinition();
         $allow_duplicates = $config->get("CSS.AllowDuplicates");
 
 
         // According to the CSS2.1 spec, the places where a
         // non-delimiting semicolon can appear are in strings
         // escape sequences.   So here is some dumb hack to
         // handle quotes.
         $len = strlen($css);
         $accum = "";
         $declarations = array();
         $quoted = false;
         for ($i = 0; $i < $len; $i++) {
             $c = strcspn($css, ";'\"", $i);
             $accum .= substr($css, $i, $c);
             $i += $c;
             if ($i == $len) break;
             $d = $css[$i];
             if ($quoted) {
                 $accum .= $d;
                 if ($d == $quoted) {
                     $quoted = false;
                 }
             } else {
                 if ($d == ";") {
                     $declarations[] = $accum;
                     $accum = "";
                 } else {
                     $accum .= $d;
                     $quoted = $d;
                 }
             }
         }
         if ($accum != "") $declarations[] = $accum;
 
         $propvalues = array();
         $new_declarations = '';
 
         /**
          * Name of the current CSS property being validated.
          */
         $property = false;
         $context->register('CurrentCSSProperty', $property);
 
         foreach ($declarations as $declaration) {
             if (!$declaration) {
                 continue;
             }
             if (!strpos($declaration, ':')) {
                 continue;
             }
             list($property, $value) = explode(':', $declaration, 2);
             $property = trim($property);
             $value = trim($value);
             $ok = false;
             do {
                 if (isset($definition->info[$property])) {
                     $ok = true;
                     break;
                 }
                 if (ctype_lower($property)) {
                     break;
                 }
                 $property = strtolower($property);
                 if (isset($definition->info[$property])) {
                     $ok = true;
                     break;
                 }
             } while (0);
             if (!$ok) {
                 continue;
             }
             // inefficient call, since the validator will do this again
             if (strtolower(trim($value)) !== 'inherit') {
                 // inherit works for everything (but only on the base property)
                 $result = $definition->info[$property]->validate(
                     $value,
                     $config,
                     $context
                 );
             } else {
                 $result = 'inherit';
             }
             if ($result === false) {
                 continue;
             }
             if ($allow_duplicates) {
                 $new_declarations .= "$property:$result;";
             } else {
                 $propvalues[$property] = $result;
             }
         }
 
         $context->destroy('CurrentCSSProperty');
 
         // procedure does not write the new CSS simultaneously, so it's
         // slightly inefficient, but it's the only way of getting rid of
         // duplicates. Perhaps config to optimize it, but not now.
 
         foreach ($propvalues as $prop => $value) {
             $new_declarations .= "$prop:$value;";
         }
 
         return $new_declarations ? $new_declarations : false;
 
     }
 
 }
 
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