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.WD
  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 WD.1
  53          * @deprecated since WD.1. 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 WD.1
  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 WD.1
 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 WD.1
 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 WD.1
 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 WD.1
 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                 if ( wfEmptyMsg( $key ) ) return $name;
 333                 else return wfMsg( $key );
 334         }
 335
 336         public static function getContentModels() {
 337                 global $wgContentHandlers;
 338
 339                 return array_keys( $wgContentHandlers );
 340         }
 341
 342         public static function getAllContentFormats() {
 343                 global $wgContentHandlers;
 344
 345                 $formats = array();
 346
 347                 foreach ( $wgContentHandlers as $model => $class ) {
 348                         $handler = ContentHandler::getForModelID( $model );
 349                         $formats = array_merge( $formats, $handler->getSupportedFormats() );
 350                 }
 351
 352                 $formats = array_unique( $formats );
 353                 return $formats;
 354         }
 355
 356         // ------------------------------------------------------------------------
 357
 358         protected $mModelID;
 359         protected $mSupportedFormats;
 360
 361         /**
 362          * Constructor, initializing the ContentHandler instance with its model ID
 363          * and a list of supported formats. Values for the parameters are typically
 364          * provided as literals by subclass's constructors.
 365          *
 366          * @param $modelId String (use CONTENT_MODEL_XXX constants).
 367          * @param $formats array List for supported serialization formats
 368          *    (typically as MIME types)
 369          */
 370         public function __construct( $modelId, $formats ) {
 371                 $this->mModelID = $modelId;
 372                 $this->mSupportedFormats = $formats;
 373
 374                 $this->mModelName = preg_replace( '/(Content)?Handler$/', '', get_class( $this ) );
 375                 $this->mModelName = preg_replace( '/[_\\\\]/', '', $this->mModelName );
 376                 $this->mModelName = strtolower( $this->mModelName );
 377         }
 378
 379         /**
 380          * Serializes a Content object of the type supported by this ContentHandler.
 381          *
 382          * @since WD.1
 383          *
 384          * @abstract
 385          * @param $content Content The Content object to serialize
 386          * @param $format null|String The desired serialization format
 387          * @return string Serialized form of the content
 388          */
 389         public abstract function serializeContent( Content $content, $format = null );
 390
 391         /**
 392          * Unserializes a Content object of the type supported by this ContentHandler.
 393          *
 394          * @since WD.1
 395          *
 396          * @abstract
 397          * @param $blob string serialized form of the content
 398          * @param $format null|String the format used for serialization
 399          * @return Content the Content object created by deserializing $blob
 400          */
 401         public abstract function unserializeContent( $blob, $format = null );
 402
 403         /**
 404          * Creates an empty Content object of the type supported by this
 405          * ContentHandler.
 406          *
 407          * @since WD.1
 408          *
 409          * @return Content
 410          */
 411         public abstract function makeEmptyContent();
 412
 413         /**
 414          * Returns the model id that identifies the content model this
 415          * ContentHandler can handle. Use with the CONTENT_MODEL_XXX constants.
 416          *
 417          * @since WD.1
 418          *
 419          * @return String The model ID
 420          */
 421         public function getModelID() {
 422                 return $this->mModelID;
 423         }
 424
 425         /**
 426          * Throws an MWException if $model_id is not the ID of the content model
 427          * supported by this ContentHandler.
 428          *
 429          * @since WD.1
 430          *
 431          * @param String $model_id The model to check
 432          *
 433          * @throws MWException
 434          */
 435         protected function checkModelID( $model_id ) {
 436                 if ( $model_id !== $this->mModelID ) {
 437                         throw new MWException( "Bad content model: " .
 438                                 "expected {$this->mModelID} " .
 439                                 "but got $model_id." );
 440                 }
 441         }
 442
 443         /**
 444          * Returns a list of serialization formats supported by the
 445          * serializeContent() and unserializeContent() methods of this
 446          * ContentHandler.
 447          *
 448          * @since WD.1
 449          *
 450          * @return array of serialization formats as MIME type like strings
 451          */
 452         public function getSupportedFormats() {
 453                 return $this->mSupportedFormats;
 454         }
 455
 456         /**
 457          * The format used for serialization/deserialization by default by this
 458          * ContentHandler.
 459          *
 460          * This default implementation will return the first element of the array
 461          * of formats that was passed to the constructor.
 462          *
 463          * @since WD.1
 464          *
 465          * @return string the name of the default serialization format as a MIME type
 466          */
 467         public function getDefaultFormat() {
 468                 return $this->mSupportedFormats[0];
 469         }
 470
 471         /**
 472          * Returns true if $format is a serialization format supported by this
 473          * ContentHandler, and false otherwise.
 474          *
 475          * Note that if $format is null, this method always returns true, because
 476          * null means "use the default format".
 477          *
 478          * @since WD.1
 479          *
 480          * @param $format string the serialization format to check
 481          * @return bool
 482          */
 483         public function isSupportedFormat( $format ) {
 484
 485                 if ( !$format ) {
 486                         return true; // this means "use the default"
 487                 }
 488
 489                 return in_array( $format, $this->mSupportedFormats );
 490         }
 491
 492         /**
 493          * Throws an MWException if isSupportedFormat( $format ) is not true.
 494          * Convenient for checking whether a format provided as a parameter is
 495          * actually supported.
 496          *
 497          * @param $format string the serialization format to check
 498          *
 499          * @throws MWException
 500          */
 501         protected function checkFormat( $format ) {
 502                 if ( !$this->isSupportedFormat( $format ) ) {
 503                         throw new MWException(
 504                                 "Format $format is not supported for content model "
 505                                 . $this->getModelID()
 506                         );
 507                 }
 508         }
 509
 510         /**
 511          * Returns overrides for action handlers.
 512          * Classes listed here will be used instead of the default one when
 513          * (and only when) $wgActions[$action] === true. This allows subclasses
 514          * to override the default action handlers.
 515          *
 516          * @since WD.1
 517          *
 518          * @return Array
 519          */
 520         public function getActionOverrides() {
 521                 return array();
 522         }
 523
 524         /**
 525          * Factory for creating an appropriate DifferenceEngine for this content model.
 526          *
 527          * @since WD.1
 528          *
 529          * @param $context IContextSource context to use, anything else will be
 530          *    ignored
 531          * @param $old Integer Old ID we want to show and diff with.
 532          * @param $new int|string String either 'prev' or 'next'.
 533          * @param $rcid Integer ??? FIXME (default 0)
 534          * @param $refreshCache boolean If set, refreshes the diff cache
 535          * @param $unhide boolean If set, allow viewing deleted revs
 536          *
 537          * @return DifferenceEngine
 538          */
 539         public function createDifferenceEngine( IContextSource $context,
 540                 $old = 0, $new = 0,
 541                 $rcid = 0, # FIXME: use everywhere!
 542                 $refreshCache = false, $unhide = false
 543         ) {
 544                 $this->checkModelID( $context->getTitle()->getContentModel() );
 545
 546                 $diffEngineClass = $this->getDiffEngineClass();
 547
 548                 return new $diffEngineClass( $context, $old, $new, $rcid, $refreshCache, $unhide );
 549         }
 550
 551         /**
 552          * Get the language in which the content of the given page is written.
 553          *
 554          * This default implementation just returns $wgContLang (except for pages in the MediaWiki namespace)
 555          *
 556          * Note that the pages language is not cacheable, since it may in some cases depend on user settings.
 557          *
 558          * Also note that the page language may or may not depend on the actual content of the page,
 559          * that is, this method may load the content in order to determine the language.
 560          *
 561          * @since 1.WD
 562          *
 563          * @param Title        $title the page to determine the language for.
 564          * @param Content|null $content the page's content, if you have it handy, to avoid reloading it.
 565          *
 566          * @return Language the page's language
 567          */
 568         public function getPageLanguage( Title $title, Content $content = null ) {
 569                 global $wgContLang;
 570
 571                 if ( $title->getNamespace() == NS_MEDIAWIKI ) {
 572                         // Parse mediawiki messages with correct target language
 573                         list( /* $unused */, $lang ) = MessageCache::singleton()->figureMessage( $title->getText() );
 574                         return wfGetLangObj( $lang );
 575                 }
 576
 577                 return $wgContLang;
 578         }
 579
 580         /**
 581          * Get the language in which the content of this page is written when
 582          * viewed by user. Defaults to $this->getPageLanguage(), but if the user
 583          * specified a preferred variant, the variant will be used.
 584          *
 585          * This default implementation just returns $this->getPageLanguage( $title, $content ) unless
 586          * the user specified a preferred variant.
 587          *
 588          * Note that the pages view language is not cacheable, since it depends on user settings.
 589          *
 590          * Also note that the page language may or may not depend on the actual content of the page,
 591          * that is, this method may load the content in order to determine the language.
 592          *
 593          * @since 1.WD
 594          *
 595          * @param Title        $title the page to determine the language for.
 596          * @param Content|null $content the page's content, if you have it handy, to avoid reloading it.
 597          *
 598          * @return Language the page's language for viewing
 599          */
 600         public function getPageViewLanguage( Title $title, Content $content = null ) {
 601                 $pageLang = $this->getPageLanguage( $title, $content );
 602
 603                 if ( $title->getNamespace() !== NS_MEDIAWIKI ) {
 604                         // If the user chooses a variant, the content is actually
 605                         // in a language whose code is the variant code.
 606                         $variant = $pageLang->getPreferredVariant();
 607                         if ( $pageLang->getCode() !== $variant ) {
 608                                 $pageLang = Language::factory( $variant );
 609                         }
 610                 }
 611
 612                 return $pageLang;
 613         }
 614
 615         /**
 616          * Determines whether the content type handled by this ContentHandler
 617          * can be used on the given page.
 618          *
 619          * This default implementation always returns true.
 620          * Subclasses may override this to restrict the use of this content model to specific locations,
 621          * typically based on the namespace or some other aspect of the title, such as a special suffix
 622          * (e.g. ".svg" for SVG content).
 623          *
 624          * @param Title $title the page's title.
 625          *
 626          * @return bool true if content of this kind can be used on the given page, false otherwise.
 627          */
 628         public function canBeUsedOn( Title $title ) {
 629                 return true;
 630         }
 631
 632         /**
 633          * Returns the name of the diff engine to use.
 634          *
 635          * @since WD.1
 636          *
 637          * @return string
 638          */
 639         protected function getDiffEngineClass() {
 640                 return 'DifferenceEngine';
 641         }
 642
 643         /**
 644          * Attempts to merge differences between three versions.
 645          * Returns a new Content object for a clean merge and false for failure or
 646          * a conflict.
 647          *
 648          * This default implementation always returns false.
 649          *
 650          * @since WD.1
 651          *
 652          * @param $oldContent Content|string  String
 653          * @param $myContent Content|string   String
 654          * @param $yourContent Content|string String
 655          *
 656          * @return Content|Bool
 657          */
 658         public function merge3( Content $oldContent, Content $myContent, Content $yourContent ) {
 659                 return false;
 660         }
 661
 662         /**
 663          * Return an applicable auto-summary if one exists for the given edit.
 664          *
 665          * @since WD.1
 666          *
 667          * @param $oldContent Content|null: the previous text of the page.
 668          * @param $newContent Content|null: The submitted text of the page.
 669          * @param $flags int Bit mask: a bit mask of flags submitted for the edit.
 670          *
 671          * @return string An appropriate auto-summary, or an empty string.
 672          */
 673         public function getAutosummary( Content $oldContent = null, Content $newContent = null, $flags ) {
 674                 global $wgContLang;
 675
 676                 // Decide what kind of auto-summary is needed.
 677
 678                 // Redirect auto-summaries
 679
 680                 /**
 681                  * @var $ot Title
 682                  * @var $rt Title
 683                  */
 684
 685                 $ot = !is_null( $oldContent ) ? $oldContent->getRedirectTarget() : null;
 686                 $rt = !is_null( $newContent ) ? $newContent->getRedirectTarget() : null;
 687
 688                 if ( is_object( $rt ) ) {
 689                         if ( !is_object( $ot )
 690                                 || !$rt->equals( $ot )
 691                                 || $ot->getFragment() != $rt->getFragment() )
 692                         {
 693                                 $truncatedtext = $newContent->getTextForSummary(
 694                                         250
 695                                                 - strlen( wfMessage( 'autoredircomment' )->inContentLanguage()->text() )
 696                                                 - strlen( $rt->getFullText() ) );
 697
 698                                 return wfMessage( 'autoredircomment', $rt->getFullText() )
 699                                                 ->rawParams( $truncatedtext )->inContentLanguage()->text();
 700                         }
 701                 }
 702
 703                 // New page auto-summaries
 704                 if ( $flags & EDIT_NEW && $newContent->getSize() > 0 ) {
 705                         // If they're making a new article, give its text, truncated, in
 706                         // the summary.
 707
 708                         $truncatedtext = $newContent->getTextForSummary(
 709                                 200 - strlen( wfMessage( 'autosumm-new' )->inContentLanguage()->text() ) );
 710
 711                         return wfMessage( 'autosumm-new' )->rawParams( $truncatedtext )
 712                                         ->inContentLanguage()->text();
 713                 }
 714
 715                 // Blanking auto-summaries
 716                 if ( !empty( $oldContent ) && $oldContent->getSize() > 0 && $newContent->getSize() == 0 ) {
 717                         return wfMessage( 'autosumm-blank' )->inContentLanguage()->text();
 718                 } elseif ( !empty( $oldContent )
 719                         && $oldContent->getSize() > 10 * $newContent->getSize()
 720                         && $newContent->getSize() < 500 )
 721                 {
 722                         // Removing more than 90% of the article
 723
 724                         $truncatedtext = $newContent->getTextForSummary(
 725                                 200 - strlen( wfMessage( 'autosumm-replace' )->inContentLanguage()->text() ) );
 726
 727                         return wfMessage( 'autosumm-replace' )->rawParams( $truncatedtext )
 728                                         ->inContentLanguage()->text();
 729                 }
 730
 731                 // If we reach this point, there's no applicable auto-summary for our
 732                 // case, so our auto-summary is empty.
 733                 return '';
 734         }
 735
 736         /**
 737          * Auto-generates a deletion reason
 738          *
 739          * @since WD.1
 740          *
 741          * @param $title Title: the page's title
 742          * @param &$hasHistory Boolean: whether the page has a history
 743          * @return mixed String containing deletion reason or empty string, or
 744          *    boolean false if no revision occurred
 745          *
 746          * @XXX &$hasHistory is extremely ugly, it's here because
 747          * WikiPage::getAutoDeleteReason() and Article::getReason()
 748          * have it / want it.
 749          */
 750         public function getAutoDeleteReason( Title $title, &$hasHistory ) {
 751                 $dbw = wfGetDB( DB_MASTER );
 752
 753                 // Get the last revision
 754                 $rev = Revision::newFromTitle( $title );
 755
 756                 if ( is_null( $rev ) ) {
 757                         return false;
 758                 }
 759
 760                 // Get the article's contents
 761                 $content = $rev->getContent();
 762                 $blank = false;
 763
 764                 $this->checkModelID( $content->getModel() );
 765
 766                 // If the page is blank, use the text from the previous revision,
 767                 // which can only be blank if there's a move/import/protect dummy
 768                 // revision involved
 769                 if ( $content->getSize() == 0 ) {
 770                         $prev = $rev->getPrevious();
 771
 772                         if ( $prev )    {
 773                                 $content = $prev->getContent();
 774                                 $blank = true;
 775                         }
 776                 }
 777
 778                 // Find out if there was only one contributor
 779                 // Only scan the last 20 revisions
 780                 $res = $dbw->select( 'revision', 'rev_user_text',
 781                         array(
 782                                 'rev_page' => $title->getArticleID(),
 783                                 $dbw->bitAnd( 'rev_deleted', Revision::DELETED_USER ) . ' = 0'
 784                         ),
 785                         __METHOD__,
 786                         array( 'LIMIT' => 20 )
 787                 );
 788
 789                 if ( $res === false ) {
 790                         // This page has no revisions, which is very weird
 791                         return false;
 792                 }
 793
 794                 $hasHistory = ( $res->numRows() > 1 );
 795                 $row = $dbw->fetchObject( $res );
 796
 797                 if ( $row ) { // $row is false if the only contributor is hidden
 798                         $onlyAuthor = $row->rev_user_text;
 799                         // Try to find a second contributor
 800                         foreach ( $res as $row ) {
 801                                 if ( $row->rev_user_text != $onlyAuthor ) { // Bug 22999
 802                                         $onlyAuthor = false;
 803                                         break;
 804                                 }
 805                         }
 806                 } else {
 807                         $onlyAuthor = false;
 808                 }
 809
 810                 // Generate the summary with a '$1' placeholder
 811                 if ( $blank ) {
 812                         // The current revision is blank and the one before is also
 813                         // blank. It's just not our lucky day
 814                         $reason = wfMessage( 'exbeforeblank', '$1' )->inContentLanguage()->text();
 815                 } else {
 816                         if ( $onlyAuthor ) {
 817                                 $reason = wfMessage(
 818                                         'excontentauthor',
 819                                         '$1',
 820                                         $onlyAuthor
 821                                 )->inContentLanguage()->text();
 822                         } else {
 823                                 $reason = wfMessage( 'excontent', '$1' )->inContentLanguage()->text();
 824                         }
 825                 }
 826
 827                 if ( $reason == '-' ) {
 828                         // Allow these UI messages to be blanked out cleanly
 829                         return '';
 830                 }
 831
 832                 // Max content length = max comment length - length of the comment (excl. $1)
 833                 $text = $content->getTextForSummary( 255 - ( strlen( $reason ) - 2 ) );
 834
 835                 // Now replace the '$1' placeholder
 836                 $reason = str_replace( '$1', $text, $reason );
 837
 838                 return $reason;
 839         }
 840
 841         /**
 842          * Get the Content object that needs to be saved in order to undo all revisions
 843          * between $undo and $undoafter. Revisions must belong to the same page,
 844          * must exist and must not be deleted.
 845          *
 846          * @since WD.1
 847          *
 848          * @param $current Revision The current text
 849          * @param $undo Revision The revision to undo
 850          * @param $undoafter Revision Must be an earlier revision than $undo
 851          *
 852          * @return mixed String on success, false on failure
 853          */
 854         public function getUndoContent( Revision $current, Revision $undo, Revision $undoafter ) {
 855                 $cur_content = $current->getContent();
 856
 857                 if ( empty( $cur_content ) ) {
 858                         return false; // no page
 859                 }
 860
 861                 $undo_content = $undo->getContent();
 862                 $undoafter_content = $undoafter->getContent();
 863
 864                 $this->checkModelID( $cur_content->getModel() );
 865                 $this->checkModelID( $undo_content->getModel() );
 866                 $this->checkModelID( $undoafter_content->getModel() );
 867
 868                 if ( $cur_content->equals( $undo_content ) ) {
 869                         // No use doing a merge if it's just a straight revert.
 870                         return $undoafter_content;
 871                 }
 872
 873                 $undone_content = $this->merge3( $undo_content, $undoafter_content, $cur_content );
 874
 875                 return $undone_content;
 876         }
 877
 878         /**
 879          * Get parser options suitable for rendering the primary article wikitext
 880          *
 881          * @param IContextSource|User|string $context One of the following:
 882          *        - IContextSource: Use the User and the Language of the provided
 883          *                                            context
 884          *        - User: Use the provided User object and $wgLang for the language,
 885          *                                            so use an IContextSource object if possible.
 886          *        - 'canonical': Canonical options (anonymous user with default
 887          *                                            preferences and content language).
 888          *
 889          * @param IContextSource|User|string $context
 890          *
 891          * @throws MWException
 892          * @return ParserOptions
 893          */
 894         public function makeParserOptions( $context ) {
 895                 global $wgContLang;
 896
 897                 if ( $context instanceof IContextSource ) {
 898                         $options = ParserOptions::newFromContext( $context );
 899                 } elseif ( $context instanceof User ) { // settings per user (even anons)
 900                         $options = ParserOptions::newFromUser( $context );
 901                 } elseif ( $context === 'canonical' ) { // canonical settings
 902                         $options = ParserOptions::newFromUserAndLang( new User, $wgContLang );
 903                 } else {
 904                         throw new MWException( "Bad context for parser options: $context" );
 905                 }
 906
 907                 $options->enableLimitReport(); // show inclusion/loop reports
 908                 $options->setTidy( true ); // fix bad HTML
 909
 910                 return $options;
 911         }
 912
 913         /**
 914          * Returns true for content models that support caching using the
 915          * ParserCache mechanism. See WikiPage::isParserCacheUser().
 916          *
 917          * @since WD.1
 918          *
 919          * @return bool
 920          */
 921         public function isParserCacheSupported() {
 922                 return true;
 923         }
 924
 925         /**
 926          * Returns true if this content model supports sections.
 927          *
 928          * This default implementation returns false.
 929          *
 930          * @return boolean whether sections are supported.
 931          */
 932         public function supportsSections() {
 933                 return false;
 934         }
 935
 936         /**
 937          * Call a legacy hook that uses text instead of Content objects.
 938          * Will log a warning when a matching hook function is registered.
 939          * If the textual representation of the content is changed by the
 940          * hook function, a new Content object is constructed from the new
 941          * text.
 942          *
 943          * @param $event String: event name
 944          * @param $args Array: parameters passed to hook functions
 945          * @param $warn bool: whether to log a warning (default: true). Should generally be true,
 946          *                    may be set to false for testing.
 947          *
 948          * @return Boolean True if no handler aborted the hook
 949          */
 950         public static function runLegacyHooks( $event, $args = array(), $warn = true ) {
 951                 if ( !Hooks::isRegistered( $event ) ) {
 952                         return true; // nothing to do here
 953                 }
 954
 955                 if ( $warn ) {
 956                         wfWarn( "Using obsolete hook $event" );
 957                 }
 958
 959                 // convert Content objects to text
 960                 $contentObjects = array();
 961                 $contentTexts = array();
 962
 963                 foreach ( $args as $k => $v ) {
 964                         if ( $v instanceof Content ) {
 965                                 /* @var Content $v */
 966
 967                                 $contentObjects[$k] = $v;
 968
 969                                 $v = $v->serialize();
 970                                 $contentTexts[ $k ] = $v;
 971                                 $args[ $k ] = $v;
 972                         }
 973                 }
 974
 975                 // call the hook functions
 976                 $ok = wfRunHooks( $event, $args );
 977
 978                 // see if the hook changed the text
 979                 foreach ( $contentTexts as $k => $orig ) {
 980                         /* @var Content $content */
 981
 982                         $modified = $args[ $k ];
 983                         $content = $contentObjects[$k];
 984
 985                         if ( $modified !== $orig ) {
 986                                 // text was changed, create updated Content object
 987                                 $content = $content->getContentHandler()->unserializeContent( $modified );
 988                         }
 989
 990                         $args[ $k ] = $content;
 991                 }
 992
 993                 return $ok;
 994         }
 995 }
 996
 997 /**
 998  * @since WD.1
 999  */
1000 abstract class TextContentHandler extends ContentHandler {
1001
1002         public function __construct( $modelId, $formats ) {
1003                 parent::__construct( $modelId, $formats );
1004         }
1005
1006         /**
1007          * Returns the content's text as-is.
1008          *
1009          * @param $content Content
1010          * @param $format string|null
1011          * @return mixed
1012          */
1013         public function serializeContent( Content $content, $format = null ) {
1014                 $this->checkFormat( $format );
1015                 return $content->getNativeData();
1016         }
1017
1018         /**
1019          * Attempts to merge differences between three versions. Returns a new
1020          * Content object for a clean merge and false for failure or a conflict.
1021          *
1022          * All three Content objects passed as parameters must have the same
1023          * content model.
1024          *
1025          * This text-based implementation uses wfMerge().
1026          *
1027          * @param $oldContent \Content|string  String
1028          * @param $myContent \Content|string   String
1029          * @param $yourContent \Content|string String
1030          *
1031          * @return Content|Bool
1032          */
1033         public function merge3( Content $oldContent, Content $myContent, Content $yourContent ) {
1034                 $this->checkModelID( $oldContent->getModel() );
1035                 $this->checkModelID( $myContent->getModel() );
1036                 $this->checkModelID( $yourContent->getModel() );
1037
1038                 $format = $this->getDefaultFormat();
1039
1040                 $old = $this->serializeContent( $oldContent, $format );
1041                 $mine = $this->serializeContent( $myContent, $format );
1042                 $yours = $this->serializeContent( $yourContent, $format );
1043
1044                 $ok = wfMerge( $old, $mine, $yours, $result );
1045
1046                 if ( !$ok ) {
1047                         return false;
1048                 }
1049
1050                 if ( !$result ) {
1051                         return $this->makeEmptyContent();
1052                 }
1053
1054                 $mergedContent = $this->unserializeContent( $result, $format );
1055                 return $mergedContent;
1056         }
1057
1058 }
1059
1060 /**
1061  * @since WD.1
1062  */
1063 class WikitextContentHandler extends TextContentHandler {
1064
1065         public function __construct( $modelId = CONTENT_MODEL_WIKITEXT ) {
1066                 parent::__construct( $modelId, array( CONTENT_FORMAT_WIKITEXT ) );
1067         }
1068
1069         public function unserializeContent( $text, $format = null ) {
1070                 $this->checkFormat( $format );
1071
1072                 return new WikitextContent( $text );
1073         }
1074
1075         public function makeEmptyContent() {
1076                 return new WikitextContent( '' );
1077         }
1078
1079         /**
1080          * Returns true because wikitext supports sections.
1081          *
1082          * @return boolean whether sections are supported.
1083          */
1084         public function supportsSections() {
1085                 return true;
1086         }
1087 }
1088
1089 # XXX: make ScriptContentHandler base class, do highlighting stuff there?
1090
1091 /**
1092  * @since WD.1
1093  */
1094 class JavaScriptContentHandler extends TextContentHandler {
1095
1096         public function __construct( $modelId = CONTENT_MODEL_JAVASCRIPT ) {
1097                 parent::__construct( $modelId, array( CONTENT_FORMAT_JAVASCRIPT ) );
1098         }
1099
1100         public function unserializeContent( $text, $format = null ) {
1101                 $this->checkFormat( $format );
1102
1103                 return new JavaScriptContent( $text );
1104         }
1105
1106         public function makeEmptyContent() {
1107                 return new JavaScriptContent( '' );
1108         }
1109
1110         /**
1111          * Returns the english language, because JS is english, and should be handled as such.
1112          *
1113          * @return Language wfGetLangObj( 'en' )
1114          *
1115          * @see ContentHandler::getPageLanguage()
1116          */
1117         public function getPageLanguage( Title $title, Content $content = null ) {
1118                 return wfGetLangObj( 'en' );
1119         }
1120
1121         /**
1122          * Returns the english language, because CSS is english, and should be handled as such.
1123          *
1124          * @return Language wfGetLangObj( 'en' )
1125          *
1126          * @see ContentHandler::getPageViewLanguage()
1127          */
1128         public function getPageViewLanguage( Title $title, Content $content = null ) {
1129                 return wfGetLangObj( 'en' );
1130         }
1131 }
1132
1133 /**
1134  * @since WD.1
1135  */
1136 class CssContentHandler extends TextContentHandler {
1137
1138         public function __construct( $modelId = CONTENT_MODEL_CSS ) {
1139                 parent::__construct( $modelId, array( CONTENT_FORMAT_CSS ) );
1140         }
1141
1142         public function unserializeContent( $text, $format = null ) {
1143                 $this->checkFormat( $format );
1144
1145                 return new CssContent( $text );
1146         }
1147
1148         public function makeEmptyContent() {
1149                 return new CssContent( '' );
1150         }
1151
1152         /**
1153          * Returns the english language, because CSS is english, and should be handled as such.
1154          *
1155          * @return Language wfGetLangObj( 'en' )
1156          *
1157          * @see ContentHandler::getPageLanguage()
1158          */
1159         public function getPageLanguage( Title $title, Content $content = null ) {
1160                 return wfGetLangObj( 'en' );
1161         }
1162
1163         /**
1164          * Returns the english language, because CSS is english, and should be handled as such.
1165          *
1166          * @return Language wfGetLangObj( 'en' )
1167          *
1168          * @see ContentHandler::getPageViewLanguage()
1169          */
1170         public function getPageViewLanguage( Title $title, Content $content = null ) {
1171                 return wfGetLangObj( 'en' );
1172         }
1173 }