XHTMLCompiler/DOMFilter.php

   1 <?php
   2
   3 /**
   4  * Represents a filter that performs processing on documents. Read-only.
   5  */
   6 abstract class XHTMLCompiler_DOMFilter extends XHTMLCompiler_Filter
   7 {
   8
   9     /**
  10      * If set, DOMFilter will allocate a namespace for the filter
  11      * and assign it to this prefix.
  12      * @warning May not be 'html' or 'xc', because these are already
  13      *          allocated for the core namespaces.
  14      */
  15     protected $prefix;
  16
  17     /**
  18      * Allocated namespace for the filter, or default 'xc' one.
  19      */
  20     protected $ns;
  21
  22     /**
  23      * List of attributes the extension adds to the namespace,
  24      * helps prevent naming conflicts.
  25      */
  26     protected $xcAttr = array();
  27     public function getXCAttributesDefined() {
  28         return $this->xcAttr;
  29     }
  30
  31
  32     /**
  33      * Defines a filter that processes a DOMDocument.
  34      * @note Return is not used as objects are passed "by reference", and
  35      *       thus edits we make will be globally reflected.
  36      * @param $dom DOMDocument to process
  37      * @param $page XHTMLCompiler_Page object representing the context
  38      */
  39     abstract public function process(DOMDocument $dom, $page);
  40
  41     /**
  42      * Performs common initialization of DOM and XPath
  43      */
  44     public function setup($dom) {
  45         $this->dom = $dom;
  46         $this->xpath = new DOMXPath($dom);
  47         // defaults
  48         $ns['html'] = "http://www.w3.org/1999/xhtml";
  49         $this->ns = $ns['xc'] = "urn:xhtml-compiler";
  50         if (isset($this->prefix)) {
  51             if ($this->prefix == 'html' || $this->prefix == 'xc') {
  52                 throw new Exception('Prefix for ' . get_class($this) .
  53                     'may not be the reserved ' . $this->prefix);
  54             }
  55             $this->ns = $ns[$this->prefix] = "urn:xhtml-compiler:" . $this->name;
  56         }
  57         foreach ($ns as $prefix => $uri) {
  58             $this->xpath->registerNamespace($prefix, $uri);
  59         }
  60     }
  61
  62     /**
  63      * XPath object for the current DOM
  64      */
  65     private $xpath;
  66
  67     /**
  68      * Current DOMDocument
  69      */
  70     private $dom;
  71
  72     /**
  73      * Querys a DOM with an XPath expression
  74      * @param $expr XPath expression to evaluate
  75      * @param $context Context node
  76      */
  77     protected function query($expr, $context = false) {
  78         if (!$this->dom) throw new Exception('Filter must be setup before using convenience functions');
  79         if (!$context) return $this->xpath->query($expr);
  80         return $this->xpath->query($expr, $context);
  81     }
  82
  83     /**
  84      * Retrieves a namespaced attribute from an element, and then deletes it.
  85      * @note This is best for proprietary attributes that, once you grab
  86      *       their data, they should be removed from the DOM for validation's
  87      *       sake.
  88      * @param $node Node to remove attribute from
  89      * @param $ns Namespace of attribute
  90      * @param $name Name of attribute
  91      */
  92     protected function confiscateAttr($node, $ns, $name) {
  93         $value = $node->getAttributeNS($ns, $name);
  94         $node->removeAttributeNS($ns, $name);
  95         return $value;
  96     }
  97 }
  98
  99 ?>