File indexing completed on 2024-12-22 05:36:22

 <?php
 
 /**
  * Registry for retrieving specific URI scheme validator objects.
  */
 class HTMLPurifier_URISchemeRegistry
 {
 
     /**
      * Retrieve sole instance of the registry.
      * @param HTMLPurifier_URISchemeRegistry $prototype Optional prototype to overload sole instance with,
      *                   or bool true to reset to default registry.
      * @return HTMLPurifier_URISchemeRegistry
      * @note Pass a registry object $prototype with a compatible interface and
      *       the function will copy it and return it all further times.
      */
     public static function instance($prototype = null)
     {
         static $instance = null;
         if ($prototype !== null) {
             $instance = $prototype;
         } elseif ($instance === null || $prototype == true) {
             $instance = new HTMLPurifier_URISchemeRegistry();
         }
         return $instance;
     }
 
     /**
      * Cache of retrieved schemes.
      * @type HTMLPurifier_URIScheme[]
      */
     protected $schemes = array();
 
     /**
      * Retrieves a scheme validator object
      * @param string $scheme String scheme name like http or mailto
      * @param HTMLPurifier_Config $config
      * @param HTMLPurifier_Context $context
      * @return HTMLPurifier_URIScheme
      */
     public function getScheme($scheme, $config, $context)
     {
         if (!$config) {
             $config = HTMLPurifier_Config::createDefault();
         }
 
         // important, otherwise attacker could include arbitrary file
         $allowed_schemes = $config->get('URI.AllowedSchemes');
         if (!$config->get('URI.OverrideAllowedSchemes') &&
             !isset($allowed_schemes[$scheme])
         ) {
             return;
         }
 
         if (isset($this->schemes[$scheme])) {
             return $this->schemes[$scheme];
         }
         if (!isset($allowed_schemes[$scheme])) {
             return;
         }
 
         $class = 'HTMLPurifier_URIScheme_' . $scheme;
         if (!class_exists($class)) {
             return;
         }
         $this->schemes[$scheme] = new $class();
         return $this->schemes[$scheme];
     }
 
     /**
      * Registers a custom scheme to the cache, bypassing reflection.
      * @param string $scheme Scheme name
      * @param HTMLPurifier_URIScheme $scheme_obj
      */
     public function register($scheme, $scheme_obj)
     {
         $this->schemes[$scheme] = $scheme_obj;
     }
 }
 
 // vim: et sw=4 sts=4