XHTMLCompiler/FilterManager.php

   1 <?php
   2
   3 /**
   4  * Manages various filters in a document, and performs text processing
   5  */
   6 class XHTMLCompiler_FilterManager
   7 {
   8
   9     protected $preTextFilters = array();
  10     protected $postTextFilters = array();
  11     protected $DOMFilters = array();
  12     protected $Markup = array('xhtml' => true);
  13     protected $xcAttr = array();
  14
  15     protected $errors = array();
  16     protected $deps = array();
  17
  18     /**
  19      * Adds a pre-processing text filter to the queue.
  20      * @note Filters added here are run before the document is
  21      *       parsed into a DOM. Suggested use is for transforming
  22      *       non-XML style specialized markup.
  23      * @param $filter XHTMLCompiler_TextFilter
  24      */
  25     public function addPreTextFilter($filter) {
  26         $filter = $this->loadFilter($filter, 'TextFilter');
  27         $n = $filter->getName();
  28         if (isset($this->preTextFilters[$n])) {
  29             throw new Exception('Cannot overload pre text filter ' .
  30                 $filter->getName());
  31         }
  32         return $this->preTextFilters[$n] = $filter;
  33     }
  34
  35     /**
  36      * Adds a post-processing text filter to the queue.
  37      * @note Filters added here are run after the document has been
  38      *       parsed into a DOM and then serialized back. Suggested use
  39      *       is for fixing cosmetic issues with the source.
  40      * @warning Anything done on this step will not have its
  41      *          well-formedness corrected, so be careful.
  42      * @param $filter XHTMLCompiler_TextFilter
  43      */
  44     public function addPostTextFilter($filter) {
  45         $filter = $this->loadFilter($filter, 'TextFilter');
  46         $n = $filter->getName();
  47         if (isset($this->postTextFilters[$n])) {
  48             throw new Exception('Cannot overload post text filter ' .
  49                 $filter->getName());
  50         }
  51         return $this->postTextFilters[$n] = $filter;
  52     }
  53
  54     /**
  55      * Adds a DOM-processing filter to the queue
  56      * @param $filter XHTMLCompiler_DOMFilter
  57      */
  58     public function addDOMFilter($filter) {
  59         $filter = $this->loadFilter($filter, 'DOMFilter');
  60         $n = $filter->getName();
  61         if (isset($this->DOMFilters[$n])) {
  62             throw new Exception('Cannot overload DOM filter ' .
  63                 $filter->getName());
  64         }
  65         $attributes = $filter->getXCAttributesDefined();
  66         foreach ($attributes as $attribute) {
  67             if (isset($this->xcAttr[$attribute])) {
  68                 throw new Exception('Duplicate attribute definition for '.
  69                     'xc:' . $attribute);
  70             }
  71             $this->xcAttr[$attribute] = true;
  72         }
  73         return $this->DOMFilters[$n] = $filter;
  74     }
  75
  76     public function addMarkup($ext, $filter) {
  77         $filter = $this->loadFilter($filter, 'Markup');
  78         if (isset($this->Markup[$ext])) {
  79             throw new Exception('Cannot overload extension ' . $ext);
  80         }
  81         return $this->Markup[$ext] = $filter;
  82     }
  83
  84     public function getMarkup() {
  85         return $this->Markup;
  86     }
  87
  88     /**
  89      * If filter is string, load the filter based on a few guesses
  90      * @param $filter String or object filter
  91      */
  92     protected function loadFilter($filter, $subclass) {
  93         if (is_string($filter)) {
  94             $class = "XHTMLCompiler_{$subclass}_$filter";
  95             if (class_exists($class)) {
  96                 $filter = new $class;
  97             } elseif (class_exists($filter)) {
  98                 $filter = new $filter;
  99             } else {
 100                 require "$subclass/$filter.php";
 101                 $filter = new $class;
 102             }
 103         }
 104         return $filter;
 105     }
 106
 107     /** Returns the dependency array accumulated from the filter run */
 108     public function getDeps() {return $this->deps;}
 109
 110     /** Adds a file to the dependency list */
 111     public function addDependency($filename) {
 112         $this->deps[$filename] = filemtime($filename);
 113     }
 114
 115     /**
 116      * Accepts a page's text and turns it into its DOM representation.
 117      * Text, initial validation and XIncludes will be processed before
 118      * returning. DOM filters will *not* be processed.
 119      * @param $text String text to be processed
 120      * @param
 121      */
 122     public function parse($text, $page) {
 123         $markup = $this->Markup[$page->getSourceExt()];
 124         if (!is_bool($markup)) {
 125             // do markup pre-processing
 126             $text = $markup->process($text, $page, $this);
 127             // Conceivably, if something properly put things into
 128             // DOM form before kicking it out, this wouldn't work;
 129             // such a case is highly unlikely though.
 130         }
 131
 132         // do pre-text processing
 133         foreach ($this->preTextFilters as $filter) {
 134             $text = $filter->process($text, $page, $this);
 135         }
 136
 137         // generate the DOM
 138         $this->setupXMLCatalog();
 139         $dom = $this->createDOM($text);
 140
 141         $this->analyzeInternalSubset($dom);
 142
 143         // validate the document to force the entities to be resolved,
 144         // we don't actually care about the errors
 145         set_error_handler(array($this, 'muteErrorHandler'));
 146         $dom->validate();
 147         restore_error_handler();
 148
 149         $this->analyzeXIncludes($dom);
 150         $dom->xinclude();
 151
 152         return $dom;
 153     }
 154
 155     /**
 156      * Accepts a page's text (usually XHTML) and processes it.
 157      * @param $text String text to be processed
 158      * @param $page XHTMLCompiler_Page representing currently processed page
 159      */
 160     public function process($text, $page) {
 161
 162         $dom = $this->parse($text, $page);
 163
 164         // run DOM filters
 165         foreach ($this->DOMFilters as $filter) {
 166             $filter->setup($dom);
 167             $filter->process($dom, $page, $this);
 168         }
 169
 170         // translate back to text
 171         $text = $dom->saveXML();
 172
 173         // remove all non-default namespace declarations, may change,
 174         // but for now embedded XML namespaces are not cross-browser friendly
 175         $text = preg_replace('/ xmlns:.+?=".+?"/', '', $text);
 176         // scrub out custom DTD additions
 177         $text = preg_replace('/(<!DOCTYPE[^>]*?) ?\[[^\]]+\]/', '\1', $text);
 178         foreach ($this->postTextFilters as $filter) {
 179             $text = $filter->process($text, $page, $this);
 180         }
 181         // replace all CDATA sections
 182         $text = preg_replace_callback(
 183             '/<!\[CDATA\[(.+?)\]\]>/s',
 184             array('XHTMLCompiler_FilterManager', 'cdataCallback'),
 185             $text
 186         );
 187
 188         // replace any redundant xmlns sections, although they are
 189         // valid they interfere with DTD validation
 190         $text = preg_replace(
 191             '#(<(?!html)[^>]+) xmlns="http://www.w3.org/1999/xhtml"#',
 192             '$1',
 193             $text
 194         );
 195
 196         // okay, now finally do validation, and let the errors get
 197         // spit out if there are some collect parse errors
 198         set_error_handler(array($this, 'validationErrorHandler'));
 199         $dom->loadXML($text);
 200         $status = $dom->validate();
 201         restore_error_handler();
 202         if (!$status || !empty($this->errors)) {
 203             $this->buildErrors($dom);
 204             $text = $dom->saveXML();
 205         }
 206
 207         return $text;
 208     }
 209
 210     public static function cdataCallback($matches) {
 211         return htmlspecialchars($matches[1], ENT_NOQUOTES, 'UTF-8');
 212     }
 213
 214     /**
 215      * Temporary error handler to use when validating a document
 216      */
 217     public function validationErrorHandler($n, $text) {
 218         $this->errors[] = $text;
 219     }
 220
 221     /**
 222      * Handler that mutes all errors
 223      */
 224     public function muteErrorHandler($n, $t) {}
 225
 226     /**
 227      * Sets up an XML catalog to speed up entity resolution
 228      */
 229     public function setupXMLCatalog() {
 230         $catalog = XHTMLCOMPILER . '/catalog/catalog.xml';
 231         if ($catalog[1] == ':') $catalog = substr($catalog, 2); // remove drive
 232         putenv('XML_CATALOG_FILES=' . $catalog);
 233     }
 234
 235     /**
 236      * Creates a reasonable well default configured DOM
 237      * @param string $xml XML to load DOM with
 238      */
 239     public function createDOM($text = false) {
 240         $dom = new DOMDocument();
 241         $dom->preserveWhiteSpace = false;
 242         $dom->formatOutput = true;
 243         $dom->resolveExternals = true;
 244
 245         // todo: somehow, collect information on which entity files
 246         // are being added to the document, and add to xc-deps.
 247         $dom->substituteEntities = true; // allows for custom entities too!
 248
 249         if ($text !== false) $dom->loadXML($text);
 250
 251         return $dom;
 252     }
 253
 254     /**
 255      * Analyzes the internal subset of a DOM, registering any file
 256      * entity definitions as dependencies
 257      */
 258     public function analyzeInternalSubset($dom) {
 259         if (empty($dom->doctype) || !is_object($dom->doctype)) return;
 260         $internal_subset = $dom->doctype->internalSubset;
 261         if ($internal_subset) {
 262             // there are some entities that need to be registered to
 263             // the dependency list. Match ones that declare SYSTEM
 264             // '<!ENTITY' S '%' S  Name  S  PEDef  S? '>'
 265             preg_match_all(
 266               '/<!ENTITY\s+%\s+[^\s]+\s+(?:PUBLIC.+?)?SYSTEM\s+(?:"([^"]*)"|\'([^\']*)\')\s*>/s',
 267               $internal_subset,
 268               $matches
 269             );
 270             foreach ($matches[1] as $filename) {
 271                 // $filename will always be relative to web root, so
 272                 // no munging necessary
 273                 $this->addDependency($filename);
 274             }
 275         }
 276     }
 277
 278     /**
 279      * Analyzes a documents XIncludes and registers necessary dependencies.
 280      * Make sure you call this before calling $dom->xinclude
 281      * @param DOMDocument $dom to process
 282      * @todo Factor into a DOMFilter
 283      * @todo Handle arbitrary nestings of includes
 284      */
 285     public function analyzeXIncludes($dom) {
 286         $xpath = new DOMXPath($dom);
 287         $xpath->registerNamespace('xi', $ns = 'http://www.w3.org/2001/XInclude');
 288         $nodes = $xpath->query('//xi:include');
 289         foreach ($nodes as $node) {
 290             if (! $node instanceof DOMElement) continue;
 291             if (! $filename = $node->getAttribute('href')) continue;
 292             $this->addDependency($filename);
 293             $sub_dom = new DOMDocument();
 294             $sub_dom->load($filename);
 295             $this->analyzeInternalSubset($sub_dom);
 296         }
 297     }
 298
 299     /**
 300      * Adds validation errors to the output document as a message
 301      */
 302     public function buildErrors($dom) {
 303         // This should output some error to command line utility
 304         $body = $dom->getElementsByTagName('body')->item(0);
 305         if (!$body) {
 306             $dom->appendChild($html = $dom->createElement('html'));
 307             $html->appendChild($body = $dom->createElement('body'));
 308         }
 309         $warning = $dom->createElement('div');
 310         $warning->setAttribute('class', 'warning');
 311         $warning->appendChild($dom->createElement('h2', 'Warning: Errors'));
 312         $warning->appendChild($dom->createElement('p', 'This document has validation errors:'));
 313         $list = $dom->createElement('ul');
 314         foreach ($this->errors as $error) {
 315             // strip-tags removes HTML tags to make the plaintext output
 316             // more friendly, IS NOT for security reasons
 317             $list->appendChild($dom->createElement('li', strip_tags($error)));
 318         }
 319         $warning->appendChild($list);
 320         $body->insertBefore($warning, $body->childNodes->item(0));
 321     }
 322
 323 }