includes/content/ContentHandler.php

   1 <?php
   2
   3 /**
   4  * Exception representing a failure to serialize or unserialize a content object.
   5  */
   6 class MWContentSerializationException extends MWException {
   7
   8 }
   9
  10 /**
  11  * A content handler knows how do deal with a specific type of content on a wiki
  12  * page. Content is stored in the database in a serialized form (using a
  13  * serialization format a.k.a. MIME type) and is unserialized into its native
  14  * PHP representation (the content model), which is wrapped in an instance of
  15  * the appropriate subclass of Content.
  16  *
  17  * ContentHandler instances are stateless singletons that serve, among other
  18  * things, as a factory for Content objects. Generally, there is one subclass
  19  * of ContentHandler and one subclass of Content for every type of content model.
  20  *
  21  * Some content types have a flat model, that is, their native representation
  22  * is the same as their serialized form. Examples would be JavaScript and CSS
  23  * code. As of now, this also applies to wikitext (MediaWiki's default content
  24  * type), but wikitext content may be represented by a DOM or AST structure in
  25  * the future.
  26  *
  27  * @since 1.21
  28  */
  29 abstract class ContentHandler {
  30
  31         /**
  32          * Convenience function for getting flat text from a Content object. This
  33          * should only be used in the context of backwards compatibility with code
  34          * that is not yet able to handle Content objects!
  35          *
  36          * If $content is null, this method returns the empty string.
  37          *
  38          * If $content is an instance of TextContent, this method returns the flat
  39          * text as returned by $content->getNativeData().
  40          *
  41          * If $content is not a TextContent object, the behavior of this method
  42          * depends on the global $wgContentHandlerTextFallback:
  43          * - If $wgContentHandlerTextFallback is 'fail' and $content is not a
  44          *   TextContent object, an MWException is thrown.
  45          * - If $wgContentHandlerTextFallback is 'serialize' and $content is not a
  46          *   TextContent object, $content->serialize() is called to get a string
  47          *   form of the content.
  48          * - If $wgContentHandlerTextFallback is 'ignore' and $content is not a
  49          *   TextContent object, this method returns null.
  50          * - otherwise, the behaviour is undefined.
  51          *
  52          * @since 1.21
  53          * @deprecated since 1.21. Always try to use the content object.
  54          *
  55          * @static
  56          * @param $content Content|null
  57          * @return null|string the textual form of $content, if available
  58          * @throws MWException if $content is not an instance of TextContent and
  59          *   $wgContentHandlerTextFallback was set to 'fail'.
  60          */
  61         public static function getContentText( Content $content = null ) {
  62                 global $wgContentHandlerTextFallback;
  63
  64                 if ( is_null( $content ) ) {
  65                         return '';
  66                 }
  67
  68                 if ( $content instanceof TextContent ) {
  69                         return $content->getNativeData();
  70                 }
  71
  72                 if ( $wgContentHandlerTextFallback == 'fail' ) {
  73                         throw new MWException(
  74                                 "Attempt to get text from Content with model " .
  75                                 $content->getModel()
  76                         );
  77                 }
  78
  79                 if ( $wgContentHandlerTextFallback == 'serialize' ) {
  80                         return $content->serialize();
  81                 }
  82
  83                 return null;
  84         }
  85
  86         /**
  87          * Convenience function for creating a Content object from a given textual
  88          * representation.
  89          *
  90          * $text will be deserialized into a Content object of the model specified
  91          * by $modelId (or, if that is not given, $title->getContentModel()) using
  92          * the given format.
  93          *
  94          * @since 1.21
  95          *
  96          * @static
  97          *
  98          * @param $text string the textual representation, will be
  99          *    unserialized to create the Content object
 100          * @param $title null|Title the title of the page this text belongs to.
 101          *    Required if $modelId is not provided.
 102          * @param $modelId null|string the model to deserialize to. If not provided,
 103          *    $title->getContentModel() is used.
 104          * @param $format null|string the format to use for deserialization. If not
 105          *    given, the model's default format is used.
 106          *
 107          * @return Content a Content object representing $text
 108          *
 109          * @throw MWException if $model or $format is not supported or if $text can
 110          *    not be unserialized using $format.
 111          */
 112         public static function makeContent( $text, Title $title = null,
 113                 $modelId = null, $format = null )
 114         {
 115                 if ( is_null( $modelId ) ) {
 116                         if ( is_null( $title ) ) {
 117                                 throw new MWException( "Must provide a Title object or a content model ID." );
 118                         }
 119
 120                         $modelId = $title->getContentModel();
 121                 }
 122
 123                 $handler = ContentHandler::getForModelID( $modelId );
 124                 return $handler->unserializeContent( $text, $format );
 125         }
 126
 127         /**
 128          * Returns the name of the default content model to be used for the page
 129          * with the given title.
 130          *
 131          * Note: There should rarely be need to call this method directly.
 132          * To determine the actual content model for a given page, use
 133          * Title::getContentModel().
 134          *
 135          * Which model is to be used by default for the page is determined based
 136          * on several factors:
 137          * - The global setting $wgNamespaceContentModels specifies a content model
 138          *   per namespace.
 139          * - The hook ContentHandlerDefaultModelFor may be used to override the page's default
 140          *   model.
 141          * - Pages in NS_MEDIAWIKI and NS_USER default to the CSS or JavaScript
 142          *   model if they end in .js or .css, respectively.
 143          * - Pages in NS_MEDIAWIKI default to the wikitext model otherwise.
 144          * - The hook TitleIsCssOrJsPage may be used to force a page to use the CSS
 145          *   or JavaScript model. This is a compatibility feature. The ContentHandlerDefaultModelFor
 146          *   hook should be used instead if possible.
 147          * - The hook TitleIsWikitextPage may be used to force a page to use the
 148          *   wikitext model. This is a compatibility feature. The ContentHandlerDefaultModelFor
 149          *   hook should be used instead if possible.
 150          *
 151          * If none of the above applies, the wikitext model is used.
 152          *
 153          * Note: this is used by, and may thus not use, Title::getContentModel()
 154          *
 155          * @since 1.21
 156          *
 157          * @static
 158          * @param $title Title
 159          * @return null|string default model name for the page given by $title
 160          */
 161         public static function getDefaultModelFor( Title $title ) {
 162                 global $wgNamespaceContentModels;
 163
 164                 // NOTE: this method must not rely on $title->getContentModel() directly or indirectly,
 165                 //       because it is used to initialize the mContentModel member.
 166
 167                 $ns = $title->getNamespace();
 168
 169                 $ext = false;
 170                 $m = null;
 171                 $model = null;
 172
 173                 if ( !empty( $wgNamespaceContentModels[ $ns ] ) ) {
 174                         $model = $wgNamespaceContentModels[ $ns ];
 175                 }
 176
 177                 // Hook can determine default model
 178                 if ( !wfRunHooks( 'ContentHandlerDefaultModelFor', array( $title, &$model ) ) ) {
 179                         if ( !is_null( $model ) ) {
 180                                 return $model;
 181                         }
 182                 }
 183
 184                 // Could this page contain custom CSS or JavaScript, based on the title?
 185                 $isCssOrJsPage = NS_MEDIAWIKI == $ns && preg_match( '!\.(css|js)$!u', $title->getText(), $m );
 186                 if ( $isCssOrJsPage ) {
 187                         $ext = $m[1];
 188                 }
 189
 190                 // Hook can force JS/CSS
 191                 wfRunHooks( 'TitleIsCssOrJsPage', array( $title, &$isCssOrJsPage ) );
 192
 193                 // Is this a .css subpage of a user page?
 194                 $isJsCssSubpage = NS_USER == $ns
 195                         && !$isCssOrJsPage
 196                         && preg_match( "/\\/.*\\.(js|css)$/", $title->getText(), $m );
 197                 if ( $isJsCssSubpage ) {
 198                         $ext = $m[1];
 199                 }
 200
 201                 // Is this wikitext, according to $wgNamespaceContentModels or the DefaultModelFor hook?
 202                 $isWikitext = is_null( $model ) || $model == CONTENT_MODEL_WIKITEXT;
 203                 $isWikitext = $isWikitext && !$isCssOrJsPage && !$isJsCssSubpage;
 204
 205                 // Hook can override $isWikitext
 206                 wfRunHooks( 'TitleIsWikitextPage', array( $title, &$isWikitext ) );
 207
 208                 if ( !$isWikitext ) {
 209                         switch ( $ext ) {
 210                                 case 'js':
 211                                         return CONTENT_MODEL_JAVASCRIPT;
 212                                 case 'css':
 213                                         return CONTENT_MODEL_CSS;
 214                                 default:
 215                                         return is_null( $model ) ? CONTENT_MODEL_TEXT : $model;
 216                         }
 217                 }
 218
 219                 // We established that it must be wikitext
 220
 221                 return CONTENT_MODEL_WIKITEXT;
 222         }
 223
 224         /**
 225          * Returns the appropriate ContentHandler singleton for the given title.
 226          *
 227          * @since 1.21
 228          *
 229          * @static
 230          * @param $title Title
 231          * @return ContentHandler
 232          */
 233         public static function getForTitle( Title $title ) {
 234                 $modelId = $title->getContentModel();
 235                 return ContentHandler::getForModelID( $modelId );
 236         }
 237
 238         /**
 239          * Returns the appropriate ContentHandler singleton for the given Content
 240          * object.
 241          *
 242          * @since 1.21
 243          *
 244          * @static
 245          * @param $content Content
 246          * @return ContentHandler
 247          */
 248         public static function getForContent( Content $content ) {
 249                 $modelId = $content->getModel();
 250                 return ContentHandler::getForModelID( $modelId );
 251         }
 252
 253         /**
 254          * @var Array A Cache of ContentHandler instances by model id
 255          */
 256         static $handlers;
 257
 258         /**
 259          * Returns the ContentHandler singleton for the given model ID. Use the
 260          * CONTENT_MODEL_XXX constants to identify the desired content model.
 261          *
 262          * ContentHandler singletons are taken from the global $wgContentHandlers
 263          * array. Keys in that array are model names, the values are either
 264          * ContentHandler singleton objects, or strings specifying the appropriate
 265          * subclass of ContentHandler.
 266          *
 267          * If a class name is encountered when looking up the singleton for a given
 268          * model name, the class is instantiated and the class name is replaced by
 269          * the resulting singleton in $wgContentHandlers.
 270          *
 271          * If no ContentHandler is defined for the desired $modelId, the
 272          * ContentHandler may be provided by the ContentHandlerForModelID hook.
 273          * If no ContentHandler can be determined, an MWException is raised.
 274          *
 275          * @since 1.21
 276          *
 277          * @static
 278          * @param $modelId String The ID of the content model for which to get a
 279          *    handler. Use CONTENT_MODEL_XXX constants.
 280          * @return ContentHandler The ContentHandler singleton for handling the
 281          *    model given by $modelId
 282          * @throws MWException if no handler is known for $modelId.
 283          */
 284         public static function getForModelID( $modelId ) {
 285                 global $wgContentHandlers;
 286
 287                 if ( isset( ContentHandler::$handlers[$modelId] ) ) {
 288                         return ContentHandler::$handlers[$modelId];
 289                 }
 290
 291                 if ( empty( $wgContentHandlers[$modelId] ) ) {
 292                         $handler = null;
 293
 294                         wfRunHooks( 'ContentHandlerForModelID', array( $modelId, &$handler ) );
 295
 296                         if ( $handler === null ) {
 297                                 throw new MWException( "No handler for model #$modelId registered in \$wgContentHandlers" );
 298                         }
 299
 300                         if ( !( $handler instanceof ContentHandler ) ) {
 301                                 throw new MWException( "ContentHandlerForModelID must supply a ContentHandler instance" );
 302                         }
 303                 } else {
 304                         $class = $wgContentHandlers[$modelId];
 305                         $handler = new $class( $modelId );
 306
 307                         if ( !( $handler instanceof ContentHandler ) ) {
 308                                 throw new MWException( "$class from \$wgContentHandlers is not compatible with ContentHandler" );
 309                         }
 310                 }
 311
 312                 ContentHandler::$handlers[$modelId] = $handler;
 313                 return ContentHandler::$handlers[$modelId];
 314         }
 315
 316         /**
 317          * Returns the localized name for a given content model.
 318          *
 319          * Model names are localized using system messages. Message keys
 320          * have the form content-model-$name, where $name is getContentModelName( $id ).
 321          *
 322          * @static
 323          * @param $name String The content model ID, as given by a CONTENT_MODEL_XXX
 324          *    constant or returned by Revision::getContentModel().
 325          *
 326          * @return string The content format's localized name.
 327          * @throws MWException if the model id isn't known.
 328          */
 329         public static function getLocalizedName( $name ) {
 330                 $key = "content-model-$name";
 331
 332                 $msg = wfMessage( $key );
 333
 334                 return $msg->exists() ? $msg->plain() : $name;
 335         }
 336
 337         public static function getContentModels() {
 338                 global $wgContentHandlers;
 339
 340                 return array_keys( $wgContentHandlers );
 341         }
 342
 343         public static function getAllContentFormats() {
 344                 global $wgContentHandlers;
 345
 346                 $formats = array();
 347
 348                 foreach ( $wgContentHandlers as $model => $class ) {
 349                         $handler = ContentHandler::getForModelID( $model );
 350                         $formats = array_merge( $formats, $handler->getSupportedFormats() );
 351                 }
 352
 353                 $formats = array_unique( $formats );
 354                 return $formats;
 355         }
 356
 357         // ------------------------------------------------------------------------
 358
 359         protected $mModelID;
 360         protected $mSupportedFormats;
 361
 362         /**
 363          * Constructor, initializing the ContentHandler instance with its model ID
 364          * and a list of supported formats. Values for the parameters are typically
 365          * provided as literals by subclass's constructors.
 366          *
 367          * @param $modelId String (use CONTENT_MODEL_XXX constants).
 368          * @param $formats array List for supported serialization formats
 369          *    (typically as MIME types)
 370          */
 371         public function __construct( $modelId, $formats ) {
 372                 $this->mModelID = $modelId;
 373                 $this->mSupportedFormats = $formats;
 374
 375                 $this->mModelName = preg_replace( '/(Content)?Handler$/', '', get_class( $this ) );
 376                 $this->mModelName = preg_replace( '/[_\\\\]/', '', $this->mModelName );
 377                 $this->mModelName = strtolower( $this->mModelName );
 378         }
 379
 380         /**
 381          * Serializes a Content object of the type supported by this ContentHandler.
 382          *
 383          * @since 1.21
 384          *
 385          * @abstract
 386          * @param $content Content The Content object to serialize
 387          * @param $format null|String The desired serialization format
 388          * @return string Serialized form of the content
 389          */
 390         public abstract function serializeContent( Content $content, $format = null );
 391
 392         /**
 393          * Unserializes a Content object of the type supported by this ContentHandler.
 394          *
 395          * @since 1.21
 396          *
 397          * @abstract
 398          * @param $blob string serialized form of the content
 399          * @param $format null|String the format used for serialization
 400          * @return Content the Content object created by deserializing $blob
 401          */
 402         public abstract function unserializeContent( $blob, $format = null );
 403
 404         /**
 405          * Creates an empty Content object of the type supported by this
 406          * ContentHandler.
 407          *
 408          * @since 1.21
 409          *
 410          * @return Content
 411          */
 412         public abstract function makeEmptyContent();
 413
 414         /**
 415          * Creates a new Content object that acts as a redirect to the given page,
 416          * or null of redirects are not supported by this content model.
 417          *
 418          * This default implementation always returns null. Subclasses supporting redirects
 419          * must override this method.
 420          *
 421          * @since 1.21
 422          *
 423          * @param Title $destination the page to redirect to.
 424          *
 425          * @return Content
 426          */
 427         public function makeRedirectContent( Title $destination ) {
 428                 return null;
 429         }
 430
 431         /**
 432          * Returns the model id that identifies the content model this
 433          * ContentHandler can handle. Use with the CONTENT_MODEL_XXX constants.
 434          *
 435          * @since 1.21
 436          *
 437          * @return String The model ID
 438          */
 439         public function getModelID() {
 440                 return $this->mModelID;
 441         }
 442
 443         /**
 444          * Throws an MWException if $model_id is not the ID of the content model
 445          * supported by this ContentHandler.
 446          *
 447          * @since 1.21
 448          *
 449          * @param String $model_id The model to check
 450          *
 451          * @throws MWException
 452          */
 453         protected function checkModelID( $model_id ) {
 454                 if ( $model_id !== $this->mModelID ) {
 455                         throw new MWException( "Bad content model: " .
 456                                 "expected {$this->mModelID} " .
 457                                 "but got $model_id." );
 458                 }
 459         }
 460
 461         /**
 462          * Returns a list of serialization formats supported by the
 463          * serializeContent() and unserializeContent() methods of this
 464          * ContentHandler.
 465          *
 466          * @since 1.21
 467          *
 468          * @return array of serialization formats as MIME type like strings
 469          */
 470         public function getSupportedFormats() {
 471                 return $this->mSupportedFormats;
 472         }
 473
 474         /**
 475          * The format used for serialization/deserialization by default by this
 476          * ContentHandler.
 477          *
 478          * This default implementation will return the first element of the array
 479          * of formats that was passed to the constructor.
 480          *
 481          * @since 1.21
 482          *
 483          * @return string the name of the default serialization format as a MIME type
 484          */
 485         public function getDefaultFormat() {
 486                 return $this->mSupportedFormats[0];
 487         }
 488
 489         /**
 490          * Returns true if $format is a serialization format supported by this
 491          * ContentHandler, and false otherwise.
 492          *
 493          * Note that if $format is null, this method always returns true, because
 494          * null means "use the default format".
 495          *
 496          * @since 1.21
 497          *
 498          * @param $format string the serialization format to check
 499          * @return bool
 500          */
 501         public function isSupportedFormat( $format ) {
 502
 503                 if ( !$format ) {
 504                         return true; // this means "use the default"
 505                 }
 506
 507                 return in_array( $format, $this->mSupportedFormats );
 508         }
 509
 510         /**
 511          * Throws an MWException if isSupportedFormat( $format ) is not true.
 512          * Convenient for checking whether a format provided as a parameter is
 513          * actually supported.
 514          *
 515          * @param $format string the serialization format to check
 516          *
 517          * @throws MWException
 518          */
 519         protected function checkFormat( $format ) {
 520                 if ( !$this->isSupportedFormat( $format ) ) {
 521                         throw new MWException(
 522                                 "Format $format is not supported for content model "
 523                                 . $this->getModelID()
 524                         );
 525                 }
 526         }
 527
 528         /**
 529          * Returns overrides for action handlers.
 530          * Classes listed here will be used instead of the default one when
 531          * (and only when) $wgActions[$action] === true. This allows subclasses
 532          * to override the default action handlers.
 533          *
 534          * @since 1.21
 535          *
 536          * @return Array
 537          */
 538         public function getActionOverrides() {
 539                 return array();
 540         }
 541
 542         /**
 543          * Factory for creating an appropriate DifferenceEngine for this content model.
 544          *
 545          * @since 1.21
 546          *
 547          * @param $context IContextSource context to use, anything else will be
 548          *    ignored
 549          * @param $old Integer Old ID we want to show and diff with.
 550          * @param $new int|string String either 'prev' or 'next'.
 551          * @param $rcid Integer ??? FIXME (default 0)
 552          * @param $refreshCache boolean If set, refreshes the diff cache
 553          * @param $unhide boolean If set, allow viewing deleted revs
 554          *
 555          * @return DifferenceEngine
 556          */
 557         public function createDifferenceEngine( IContextSource $context,
 558                 $old = 0, $new = 0,
 559                 $rcid = 0, # FIXME: use everywhere!
 560                 $refreshCache = false, $unhide = false
 561         ) {
 562                 $this->checkModelID( $context->getTitle()->getContentModel() );
 563
 564                 $diffEngineClass = $this->getDiffEngineClass();
 565
 566                 return new $diffEngineClass( $context, $old, $new, $rcid, $refreshCache, $unhide );
 567         }
 568
 569         /**
 570          * Get the language in which the content of the given page is written.
 571          *
 572          * This default implementation just returns $wgContLang (except for pages in the MediaWiki namespace)
 573          *
 574          * Note that the pages language is not cacheable, since it may in some cases depend on user settings.
 575          *
 576          * Also note that the page language may or may not depend on the actual content of the page,
 577          * that is, this method may load the content in order to determine the language.
 578          *
 579          * @since 1.21
 580          *
 581          * @param Title        $title the page to determine the language for.
 582          * @param Content|null $content the page's content, if you have it handy, to avoid reloading it.
 583          *
 584          * @return Language the page's language
 585          */
 586         public function getPageLanguage( Title $title, Content $content = null ) {
 587                 global $wgContLang;
 588
 589                 if ( $title->getNamespace() == NS_MEDIAWIKI ) {
 590                         // Parse mediawiki messages with correct target language
 591                         list( /* $unused */, $lang ) = MessageCache::singleton()->figureMessage( $title->getText() );
 592                         return wfGetLangObj( $lang );
 593                 }
 594
 595                 return $wgContLang;
 596         }
 597
 598         /**
 599          * Get the language in which the content of this page is written when
 600          * viewed by user. Defaults to $this->getPageLanguage(), but if the user
 601          * specified a preferred variant, the variant will be used.
 602          *
 603          * This default implementation just returns $this->getPageLanguage( $title, $content ) unless
 604          * the user specified a preferred variant.
 605          *
 606          * Note that the pages view language is not cacheable, since it depends on user settings.
 607          *
 608          * Also note that the page language may or may not depend on the actual content of the page,
 609          * that is, this method may load the content in order to determine the language.
 610          *
 611          * @since 1.21
 612          *
 613          * @param Title        $title the page to determine the language for.
 614          * @param Content|null $content the page's content, if you have it handy, to avoid reloading it.
 615          *
 616          * @return Language the page's language for viewing
 617          */
 618         public function getPageViewLanguage( Title $title, Content $content = null ) {
 619                 $pageLang = $this->getPageLanguage( $title, $content );
 620
 621                 if ( $title->getNamespace() !== NS_MEDIAWIKI ) {
 622                         // If the user chooses a variant, the content is actually
 623                         // in a language whose code is the variant code.
 624                         $variant = $pageLang->getPreferredVariant();
 625                         if ( $pageLang->getCode() !== $variant ) {
 626                                 $pageLang = Language::factory( $variant );
 627                         }
 628                 }
 629
 630                 return $pageLang;
 631         }
 632
 633         /**
 634          * Determines whether the content type handled by this ContentHandler
 635          * can be used on the given page.
 636          *
 637          * This default implementation always returns true.
 638          * Subclasses may override this to restrict the use of this content model to specific locations,
 639          * typically based on the namespace or some other aspect of the title, such as a special suffix
 640          * (e.g. ".svg" for SVG content).
 641          *
 642          * @param Title $title the page's title.
 643          *
 644          * @return bool true if content of this kind can be used on the given page, false otherwise.
 645          */
 646         public function canBeUsedOn( Title $title ) {
 647                 return true;
 648         }
 649
 650         /**
 651          * Returns the name of the diff engine to use.
 652          *
 653          * @since 1.21
 654          *
 655          * @return string
 656          */
 657         protected function getDiffEngineClass() {
 658                 return 'DifferenceEngine';
 659         }
 660
 661         /**
 662          * Attempts to merge differences between three versions.
 663          * Returns a new Content object for a clean merge and false for failure or
 664          * a conflict.
 665          *
 666          * This default implementation always returns false.
 667          *
 668          * @since 1.21
 669          *
 670          * @param $oldContent Content|string  String
 671          * @param $myContent Content|string   String
 672          * @param $yourContent Content|string String
 673          *
 674          * @return Content|Bool
 675          */
 676         public function merge3( Content $oldContent, Content $myContent, Content $yourContent ) {
 677                 return false;
 678         }
 679
 680         /**
 681          * Return an applicable auto-summary if one exists for the given edit.
 682          *
 683          * @since 1.21
 684          *
 685          * @param $oldContent Content|null: the previous text of the page.
 686          * @param $newContent Content|null: The submitted text of the page.
 687          * @param $flags int Bit mask: a bit mask of flags submitted for the edit.
 688          *
 689          * @return string An appropriate auto-summary, or an empty string.
 690          */
 691         public function getAutosummary( Content $oldContent = null, Content $newContent = null, $flags ) {
 692                 global $wgContLang;
 693
 694                 // Decide what kind of auto-summary is needed.
 695
 696                 // Redirect auto-summaries
 697
 698                 /**
 699                  * @var $ot Title
 700                  * @var $rt Title
 701                  */
 702
 703                 $ot = !is_null( $oldContent ) ? $oldContent->getRedirectTarget() : null;
 704                 $rt = !is_null( $newContent ) ? $newContent->getRedirectTarget() : null;
 705
 706                 if ( is_object( $rt ) ) {
 707                         if ( !is_object( $ot )
 708                                 || !$rt->equals( $ot )
 709                                 || $ot->getFragment() != $rt->getFragment() )
 710                         {
 711                                 $truncatedtext = $newContent->getTextForSummary(
 712                                         250
 713                                                 - strlen( wfMessage( 'autoredircomment' )->inContentLanguage()->text() )
 714                                                 - strlen( $rt->getFullText() ) );
 715
 716                                 return wfMessage( 'autoredircomment', $rt->getFullText() )
 717                                                 ->rawParams( $truncatedtext )->inContentLanguage()->text();
 718                         }
 719                 }
 720
 721                 // New page auto-summaries
 722                 if ( $flags & EDIT_NEW && $newContent->getSize() > 0 ) {
 723                         // If they're making a new article, give its text, truncated, in
 724                         // the summary.
 725
 726                         $truncatedtext = $newContent->getTextForSummary(
 727                                 200 - strlen( wfMessage( 'autosumm-new' )->inContentLanguage()->text() ) );
 728
 729                         return wfMessage( 'autosumm-new' )->rawParams( $truncatedtext )
 730                                         ->inContentLanguage()->text();
 731                 }
 732
 733                 // Blanking auto-summaries
 734                 if ( !empty( $oldContent ) && $oldContent->getSize() > 0 && $newContent->getSize() == 0 ) {
 735                         return wfMessage( 'autosumm-blank' )->inContentLanguage()->text();
 736                 } elseif ( !empty( $oldContent )
 737                         && $oldContent->getSize() > 10 * $newContent->getSize()
 738                         && $newContent->getSize() < 500 )
 739                 {
 740                         // Removing more than 90% of the article
 741
 742                         $truncatedtext = $newContent->getTextForSummary(
 743                                 200 - strlen( wfMessage( 'autosumm-replace' )->inContentLanguage()->text() ) );
 744
 745                         return wfMessage( 'autosumm-replace' )->rawParams( $truncatedtext )
 746                                         ->inContentLanguage()->text();
 747                 }
 748
 749                 // If we reach this point, there's no applicable auto-summary for our
 750                 // case, so our auto-summary is empty.
 751                 return '';
 752         }
 753
 754         /**
 755          * Auto-generates a deletion reason
 756          *
 757          * @since 1.21
 758          *
 759          * @param $title Title: the page's title
 760          * @param &$hasHistory Boolean: whether the page has a history
 761          * @return mixed String containing deletion reason or empty string, or
 762          *    boolean false if no revision occurred
 763          *
 764          * @XXX &$hasHistory is extremely ugly, it's here because
 765          * WikiPage::getAutoDeleteReason() and Article::getReason()
 766          * have it / want it.
 767          */
 768         public function getAutoDeleteReason( Title $title, &$hasHistory ) {
 769                 $dbw = wfGetDB( DB_MASTER );
 770
 771                 // Get the last revision
 772                 $rev = Revision::newFromTitle( $title );
 773
 774                 if ( is_null( $rev ) ) {
 775                         return false;
 776                 }
 777
 778                 // Get the article's contents
 779                 $content = $rev->getContent();
 780                 $blank = false;
 781
 782                 $this->checkModelID( $content->getModel() );
 783
 784                 // If the page is blank, use the text from the previous revision,
 785                 // which can only be blank if there's a move/import/protect dummy
 786                 // revision involved
 787                 if ( $content->getSize() == 0 ) {
 788                         $prev = $rev->getPrevious();
 789
 790                         if ( $prev )    {
 791                                 $content = $prev->getContent();
 792                                 $blank = true;
 793                         }
 794                 }
 795
 796                 // Find out if there was only one contributor
 797                 // Only scan the last 20 revisions
 798                 $res = $dbw->select( 'revision', 'rev_user_text',
 799                         array(
 800                                 'rev_page' => $title->getArticleID(),
 801                                 $dbw->bitAnd( 'rev_deleted', Revision::DELETED_USER ) . ' = 0'
 802                         ),
 803                         __METHOD__,
 804                         array( 'LIMIT' => 20 )
 805                 );
 806
 807                 if ( $res === false ) {
 808                         // This page has no revisions, which is very weird
 809                         return false;
 810                 }
 811
 812                 $hasHistory = ( $res->numRows() > 1 );
 813                 $row = $dbw->fetchObject( $res );
 814
 815                 if ( $row ) { // $row is false if the only contributor is hidden
 816                         $onlyAuthor = $row->rev_user_text;
 817                         // Try to find a second contributor
 818                         foreach ( $res as $row ) {
 819                                 if ( $row->rev_user_text != $onlyAuthor ) { // Bug 22999
 820                                         $onlyAuthor = false;
 821                                         break;
 822                                 }
 823                         }
 824                 } else {
 825                         $onlyAuthor = false;
 826                 }
 827
 828                 // Generate the summary with a '$1' placeholder
 829                 if ( $blank ) {
 830                         // The current revision is blank and the one before is also
 831                         // blank. It's just not our lucky day
 832                         $reason = wfMessage( 'exbeforeblank', '$1' )->inContentLanguage()->text();
 833                 } else {
 834                         if ( $onlyAuthor ) {
 835                                 $reason = wfMessage(
 836                                         'excontentauthor',
 837                                         '$1',
 838                                         $onlyAuthor
 839                                 )->inContentLanguage()->text();
 840                         } else {
 841                                 $reason = wfMessage( 'excontent', '$1' )->inContentLanguage()->text();
 842                         }
 843                 }
 844
 845                 if ( $reason == '-' ) {
 846                         // Allow these UI messages to be blanked out cleanly
 847                         return '';
 848                 }
 849
 850                 // Max content length = max comment length - length of the comment (excl. $1)
 851                 $text = $content->getTextForSummary( 255 - ( strlen( $reason ) - 2 ) );
 852
 853                 // Now replace the '$1' placeholder
 854                 $reason = str_replace( '$1', $text, $reason );
 855
 856                 return $reason;
 857         }
 858
 859         /**
 860          * Get the Content object that needs to be saved in order to undo all revisions
 861          * between $undo and $undoafter. Revisions must belong to the same page,
 862          * must exist and must not be deleted.
 863          *
 864          * @since 1.21
 865          *
 866          * @param $current Revision The current text
 867          * @param $undo Revision The revision to undo
 868          * @param $undoafter Revision Must be an earlier revision than $undo
 869          *
 870          * @return mixed String on success, false on failure
 871          */
 872         public function getUndoContent( Revision $current, Revision $undo, Revision $undoafter ) {
 873                 $cur_content = $current->getContent();
 874
 875                 if ( empty( $cur_content ) ) {
 876                         return false; // no page
 877                 }
 878
 879                 $undo_content = $undo->getContent();
 880                 $undoafter_content = $undoafter->getContent();
 881
 882                 $this->checkModelID( $cur_content->getModel() );
 883                 $this->checkModelID( $undo_content->getModel() );
 884                 $this->checkModelID( $undoafter_content->getModel() );
 885
 886                 if ( $cur_content->equals( $undo_content ) ) {
 887                         // No use doing a merge if it's just a straight revert.
 888                         return $undoafter_content;
 889                 }
 890
 891                 $undone_content = $this->merge3( $undo_content, $undoafter_content, $cur_content );
 892
 893                 return $undone_content;
 894         }
 895
 896         /**
 897          * Get parser options suitable for rendering the primary article wikitext
 898          *
 899          * @param IContextSource|User|string $context One of the following:
 900          *        - IContextSource: Use the User and the Language of the provided
 901          *                                            context
 902          *        - User: Use the provided User object and $wgLang for the language,
 903          *                                            so use an IContextSource object if possible.
 904          *        - 'canonical': Canonical options (anonymous user with default
 905          *                                            preferences and content language).
 906          *
 907          * @param IContextSource|User|string $context
 908          *
 909          * @throws MWException
 910          * @return ParserOptions
 911          */
 912         public function makeParserOptions( $context ) {
 913                 global $wgContLang;
 914
 915                 if ( $context instanceof IContextSource ) {
 916                         $options = ParserOptions::newFromContext( $context );
 917                 } elseif ( $context instanceof User ) { // settings per user (even anons)
 918                         $options = ParserOptions::newFromUser( $context );
 919                 } elseif ( $context === 'canonical' ) { // canonical settings
 920                         $options = ParserOptions::newFromUserAndLang( new User, $wgContLang );
 921                 } else {
 922                         throw new MWException( "Bad context for parser options: $context" );
 923                 }
 924
 925                 $options->enableLimitReport(); // show inclusion/loop reports
 926                 $options->setTidy( true ); // fix bad HTML
 927
 928                 return $options;
 929         }
 930
 931         /**
 932          * Returns true for content models that support caching using the
 933          * ParserCache mechanism. See WikiPage::isParserCacheUser().
 934          *
 935          * @since 1.21
 936          *
 937          * @return bool
 938          */
 939         public function isParserCacheSupported() {
 940                 return true;
 941         }
 942
 943         /**
 944          * Returns true if this content model supports sections.
 945          *
 946          * This default implementation returns false.
 947          *
 948          * @return boolean whether sections are supported.
 949          */
 950         public function supportsSections() {
 951                 return false;
 952         }
 953
 954         /**
 955          * Call a legacy hook that uses text instead of Content objects.
 956          * Will log a warning when a matching hook function is registered.
 957          * If the textual representation of the content is changed by the
 958          * hook function, a new Content object is constructed from the new
 959          * text.
 960          *
 961          * @param $event String: event name
 962          * @param $args Array: parameters passed to hook functions
 963          * @param $warn bool: whether to log a warning (default: true). Should generally be true,
 964          *                    may be set to false for testing.
 965          *
 966          * @return Boolean True if no handler aborted the hook
 967          */
 968         public static function runLegacyHooks( $event, $args = array(), $warn = true ) {
 969                 if ( !Hooks::isRegistered( $event ) ) {
 970                         return true; // nothing to do here
 971                 }
 972
 973                 if ( $warn ) {
 974                         wfWarn( "Using obsolete hook $event" );
 975                 }
 976
 977                 // convert Content objects to text
 978                 $contentObjects = array();
 979                 $contentTexts = array();
 980
 981                 foreach ( $args as $k => $v ) {
 982                         if ( $v instanceof Content ) {
 983                                 /* @var Content $v */
 984
 985                                 $contentObjects[$k] = $v;
 986
 987                                 $v = $v->serialize();
 988                                 $contentTexts[ $k ] = $v;
 989                                 $args[ $k ] = $v;
 990                         }
 991                 }
 992
 993                 // call the hook functions
 994                 $ok = wfRunHooks( $event, $args );
 995
 996                 // see if the hook changed the text
 997                 foreach ( $contentTexts as $k => $orig ) {
 998                         /* @var Content $content */
 999
1000                         $modified = $args[ $k ];
1001                         $content = $contentObjects[$k];
1002
1003                         if ( $modified !== $orig ) {
1004                                 // text was changed, create updated Content object
1005                                 $content = $content->getContentHandler()->unserializeContent( $modified );
1006                         }
1007
1008                         $args[ $k ] = $content;
1009                 }
1010
1011                 return $ok;
1012         }
1013 }
1014
1015 /**
1016  * @since 1.21
1017  */
1018 abstract class TextContentHandler extends ContentHandler {
1019
1020         public function __construct( $modelId, $formats ) {
1021                 parent::__construct( $modelId, $formats );
1022         }
1023
1024         /**
1025          * Returns the content's text as-is.
1026          *
1027          * @param $content Content
1028          * @param $format string|null
1029          * @return mixed
1030          */
1031         public function serializeContent( Content $content, $format = null ) {
1032                 $this->checkFormat( $format );
1033                 return $content->getNativeData();
1034         }
1035
1036         /**
1037          * Attempts to merge differences between three versions. Returns a new
1038          * Content object for a clean merge and false for failure or a conflict.
1039          *
1040          * All three Content objects passed as parameters must have the same
1041          * content model.
1042          *
1043          * This text-based implementation uses wfMerge().
1044          *
1045          * @param $oldContent \Content|string  String
1046          * @param $myContent \Content|string   String
1047          * @param $yourContent \Content|string String
1048          *
1049          * @return Content|Bool
1050          */
1051         public function merge3( Content $oldContent, Content $myContent, Content $yourContent ) {
1052                 $this->checkModelID( $oldContent->getModel() );
1053                 $this->checkModelID( $myContent->getModel() );
1054                 $this->checkModelID( $yourContent->getModel() );
1055
1056                 $format = $this->getDefaultFormat();
1057
1058                 $old = $this->serializeContent( $oldContent, $format );
1059                 $mine = $this->serializeContent( $myContent, $format );
1060                 $yours = $this->serializeContent( $yourContent, $format );
1061
1062                 $ok = wfMerge( $old, $mine, $yours, $result );
1063
1064                 if ( !$ok ) {
1065                         return false;
1066                 }
1067
1068                 if ( !$result ) {
1069                         return $this->makeEmptyContent();
1070                 }
1071
1072                 $mergedContent = $this->unserializeContent( $result, $format );
1073                 return $mergedContent;
1074         }
1075
1076 }
1077
1078 /**
1079  * @since 1.21
1080  */
1081 class WikitextContentHandler extends TextContentHandler {
1082
1083         public function __construct( $modelId = CONTENT_MODEL_WIKITEXT ) {
1084                 parent::__construct( $modelId, array( CONTENT_FORMAT_WIKITEXT ) );
1085         }
1086
1087         public function unserializeContent( $text, $format = null ) {
1088                 $this->checkFormat( $format );
1089
1090                 return new WikitextContent( $text );
1091         }
1092
1093         /**
1094          * @see ContentHandler::makeEmptyContent
1095          *
1096          * @return Content
1097          */
1098         public function makeEmptyContent() {
1099                 return new WikitextContent( '' );
1100         }
1101
1102
1103         /**
1104          * Returns a WikitextContent object representing a redirect to the given destination page.
1105          *
1106          * @see ContentHandler::makeRedirectContent
1107          *
1108          * @param Title $destination the page to redirect to.
1109          *
1110          * @return Content
1111          */
1112         public function makeRedirectContent( Title $destination ) {
1113                 $mwRedir = MagicWord::get( 'redirect' );
1114                 $redirectText = $mwRedir->getSynonym( 0 ) . ' [[' . $destination->getPrefixedText() . "]]\n";
1115
1116                 return new WikitextContent( $redirectText );
1117         }
1118
1119         /**
1120          * Returns true because wikitext supports sections.
1121          *
1122          * @return boolean whether sections are supported.
1123          */
1124         public function supportsSections() {
1125                 return true;
1126         }
1127 }
1128
1129 # XXX: make ScriptContentHandler base class, do highlighting stuff there?
1130
1131 /**
1132  * @since 1.21
1133  */
1134 class JavaScriptContentHandler extends TextContentHandler {
1135
1136         public function __construct( $modelId = CONTENT_MODEL_JAVASCRIPT ) {
1137                 parent::__construct( $modelId, array( CONTENT_FORMAT_JAVASCRIPT ) );
1138         }
1139
1140         public function unserializeContent( $text, $format = null ) {
1141                 $this->checkFormat( $format );
1142
1143                 return new JavaScriptContent( $text );
1144         }
1145
1146         public function makeEmptyContent() {
1147                 return new JavaScriptContent( '' );
1148         }
1149
1150         /**
1151          * Returns the english language, because JS is english, and should be handled as such.
1152          *
1153          * @return Language wfGetLangObj( 'en' )
1154          *
1155          * @see ContentHandler::getPageLanguage()
1156          */
1157         public function getPageLanguage( Title $title, Content $content = null ) {
1158                 return wfGetLangObj( 'en' );
1159         }
1160
1161         /**
1162          * Returns the english language, because CSS is english, and should be handled as such.
1163          *
1164          * @return Language wfGetLangObj( 'en' )
1165          *
1166          * @see ContentHandler::getPageViewLanguage()
1167          */
1168         public function getPageViewLanguage( Title $title, Content $content = null ) {
1169                 return wfGetLangObj( 'en' );
1170         }
1171 }
1172
1173 /**
1174  * @since 1.21
1175  */
1176 class CssContentHandler extends TextContentHandler {
1177
1178         public function __construct( $modelId = CONTENT_MODEL_CSS ) {
1179                 parent::__construct( $modelId, array( CONTENT_FORMAT_CSS ) );
1180         }
1181
1182         public function unserializeContent( $text, $format = null ) {
1183                 $this->checkFormat( $format );
1184
1185                 return new CssContent( $text );
1186         }
1187
1188         public function makeEmptyContent() {
1189                 return new CssContent( '' );
1190         }
1191
1192         /**
1193          * Returns the english language, because CSS is english, and should be handled as such.
1194          *
1195          * @return Language wfGetLangObj( 'en' )
1196          *
1197          * @see ContentHandler::getPageLanguage()
1198          */
1199         public function getPageLanguage( Title $title, Content $content = null ) {
1200                 return wfGetLangObj( 'en' );
1201         }
1202
1203         /**
1204          * Returns the english language, because CSS is english, and should be handled as such.
1205          *
1206          * @return Language wfGetLangObj( 'en' )
1207          *
1208          * @see ContentHandler::getPageViewLanguage()
1209          */
1210         public function getPageViewLanguage( Title $title, Content $content = null ) {
1211                 return wfGetLangObj( 'en' );
1212         }
1213 }