includes/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 page.
  12  * Content is stored in the database in a serialized form (using a serialization format aka mime type)
  13  * and is be unserialized into it's native PHP representation (the content model), which is wrapped in
  14  * an instance of the appropriate subclass of Content.
  15  *
  16  * ContentHandler instances are stateless singletons that serve, among other things, as a factory for
  17  * Content objects. Generally, there is one subclass of ContentHandler and one subclass of Content
  18  * for every type of content model.
  19  *
  20  * Some content types have a flat model, that is, their native representation is the
  21  * same as their serialized form. Examples would be JavaScript and CSS code. As of now,
  22  * this also applies to wikitext (mediawiki's default content type), but wikitext
  23  * content may be represented by a DOM or AST structure in the future.
  24  *
  25  * @since 1.WD
  26  */
  27 abstract class ContentHandler {
  28
  29         /**
  30          * Convenience function for getting flat text from a Content object. This should only
  31          * be used in the context of backwards compatibility with code that is not yet able
  32          * to handle Content objects!
  33          *
  34          * If $content is null, this method returns the empty string.
  35          *
  36          * If $content is an instance of TextContent, this method returns the flat text as returned by $content->getNativeData().
  37          *
  38          * If $content is not a TextContent object, the behavior of this method depends on the global $wgContentHandlerTextFallback:
  39          * * If $wgContentHandlerTextFallback is 'fail' and $content is not a TextContent object, an MWException is thrown.
  40          * * If $wgContentHandlerTextFallback is 'serialize' and $content is not a TextContent object, $content->serialize()
  41          * is called to get a string form of the content.
  42          * * If $wgContentHandlerTextFallback is 'ignore' and $content is not a TextContent object, this method returns null.
  43          * * otherwise, the behaviour is undefined.
  44          *
  45          * @since WD.1
  46          *
  47          * @static
  48          * @param Content|null $content
  49          * @return null|string the textual form of $content, if available
  50          * @throws MWException if $content is not an instance of TextContent and $wgContentHandlerTextFallback was set to 'fail'.
  51          */
  52         public static function getContentText( Content $content = null ) {
  53                 global $wgContentHandlerTextFallback;
  54
  55                 if ( is_null( $content ) ) {
  56                         return '';
  57                 }
  58
  59                 if ( $content instanceof TextContent ) {
  60                         return $content->getNativeData();
  61                 }
  62
  63                 if ( $wgContentHandlerTextFallback == 'fail' ) {
  64                         throw new MWException( "Attempt to get text from Content with model " . $content->getModel() );
  65                 }
  66
  67                 if ( $wgContentHandlerTextFallback == 'serialize' ) {
  68                         return $content->serialize();
  69                 }
  70
  71                 return null;
  72         }
  73
  74         /**
  75          * Convenience function for creating a Content object from a given textual representation.
  76          *
  77          * $text will be deserialized into a Content object of the model specified by $modelId (or,
  78          * if that is not given, $title->getContentModel()) using the given format.
  79          *
  80          * @since WD.1
  81          *
  82          * @static
  83          * @param string $text the textual representation, will be unserialized to create the Content object
  84          * @param Title $title the title of the page this text belongs to, required as a context for deserialization
  85          * @param null|String $modelId the model to deserialize to. If not provided, $title->getContentModel() is used.
  86          * @param null|String $format the format to use for deserialization. If not given, the model's default format is used.
  87          *
  88          * @return Content a Content object representing $text
  89          * @throw MWException if $model or $format is not supported or if $text can not be unserialized using $format.
  90          */
  91         public static function makeContent( $text, Title $title, $modelId = null, $format = null ) {
  92
  93                 if ( is_null( $modelId ) ) {
  94                         $modelId = $title->getContentModel();
  95                 }
  96
  97                 $handler = ContentHandler::getForModelID( $modelId );
  98                 return $handler->unserializeContent( $text, $format );
  99         }
 100
 101         /**
 102          * Returns the name of the default content model to be used for the page with the given title.
 103          *
 104          * Note: There should rarely be need to call this method directly.
 105          * To determine the actual content model for a given page, use Title::getContentModel().
 106          *
 107          * Which model is to be used per default for the page is determined based on several factors:
 108          * * The global setting $wgNamespaceContentModels specifies a content model per namespace.
 109          * * The hook DefaultModelFor may be used to override the page's default model.
 110          * * Pages in NS_MEDIAWIKI and NS_USER default to the CSS or JavaScript model if they end in .js or .css, respectively.
 111          * * Pages in NS_MEDIAWIKI default to the wikitext model otherwise.
 112          * * The hook TitleIsCssOrJsPage may be used to force a page to use the CSS or JavaScript model if they end in .js or .css, respectively.
 113          * * The hook TitleIsWikitextPage may be used to force a page to use the wikitext model.
 114          *
 115          * If none of the above applies, the wikitext model is used.
 116          *
 117          * Note: this is used by, and may thus not use, Title::getContentModel()
 118          *
 119          * @since WD.1
 120          *
 121          * @static
 122          * @param Title $title
 123          * @return null|string default model name for the page given by $title
 124          */
 125         public static function getDefaultModelFor( Title $title ) {
 126                 global $wgNamespaceContentModels;
 127
 128                 // NOTE: this method must not rely on $title->getContentModel() directly or indirectly,
 129                 //       because it is used to initialized the mContentModel member.
 130
 131                 $ns = $title->getNamespace();
 132
 133                 $ext = false;
 134                 $m = null;
 135                 $model = null;
 136
 137                 if ( !empty( $wgNamespaceContentModels[ $ns ] ) ) {
 138                         $model = $wgNamespaceContentModels[ $ns ];
 139                 }
 140
 141                 // hook can determin default model
 142                 if ( !wfRunHooks( 'ContentHandlerDefaultModelFor', array( $title, &$model ) ) ) {
 143                         if ( !is_null( $model ) ) {
 144                                 return $model;
 145                         }
 146                 }
 147
 148                 // Could this page contain custom CSS or JavaScript, based on the title?
 149                 $isCssOrJsPage = NS_MEDIAWIKI == $ns && preg_match( '!\.(css|js)$!u', $title->getText(), $m );
 150                 if ( $isCssOrJsPage ) {
 151                         $ext = $m[1];
 152                 }
 153
 154                 // hook can force js/css
 155                 wfRunHooks( 'TitleIsCssOrJsPage', array( $title, &$isCssOrJsPage ) );
 156
 157                 // Is this a .css subpage of a user page?
 158                 $isJsCssSubpage = NS_USER == $ns && !$isCssOrJsPage && preg_match( "/\\/.*\\.(js|css)$/", $title->getText(), $m );
 159                 if ( $isJsCssSubpage ) {
 160                         $ext = $m[1];
 161                 }
 162
 163                 // is this wikitext, according to $wgNamespaceContentModels or the DefaultModelFor hook?
 164                 $isWikitext = is_null( $model ) || $model == CONTENT_MODEL_WIKITEXT;
 165                 $isWikitext = $isWikitext && !$isCssOrJsPage && !$isJsCssSubpage;
 166
 167                 // hook can override $isWikitext
 168                 wfRunHooks( 'TitleIsWikitextPage', array( $title, &$isWikitext ) );
 169
 170                 if ( !$isWikitext ) {
 171                         switch ( $ext ) {
 172                                 case 'js':
 173                                         return CONTENT_MODEL_JAVASCRIPT;
 174                                 case 'css':
 175                                         return CONTENT_MODEL_CSS;
 176                                 default:
 177                                         return is_null( $model ) ? CONTENT_MODEL_TEXT : $model;
 178                         }
 179                 }
 180
 181                 // we established that is must be wikitext
 182
 183                 return CONTENT_MODEL_WIKITEXT;
 184         }
 185
 186         /**
 187          * returns the appropriate ContentHandler singleton for the given title
 188          *
 189          * @since WD.1
 190          *
 191          * @static
 192          * @param Title $title
 193          * @return ContentHandler
 194          */
 195         public static function getForTitle( Title $title ) {
 196                 $modelId = $title->getContentModel();
 197                 return ContentHandler::getForModelID( $modelId );
 198         }
 199
 200         /**
 201          * returns the appropriate ContentHandler singleton for the given Content object
 202          *
 203          * @since WD.1
 204          *
 205          * @static
 206          * @param Content $content
 207          * @return ContentHandler
 208          */
 209         public static function getForContent( Content $content ) {
 210                 $modelId = $content->getModel();
 211                 return ContentHandler::getForModelID( $modelId );
 212         }
 213
 214         /**
 215          * returns the ContentHandler singleton for the given model id. Use the CONTENT_MODEL_XXX constants to
 216          * identify the desired content model.
 217          *
 218          * ContentHandler singletons are take from the global $wgContentHandlers array. Keys in that array are
 219          * model names, the values are either ContentHandler singleton objects, or strings specifying the appropriate
 220          * subclass of ContentHandler.
 221          *
 222          * If a class name in encountered when looking up the singleton for a given model name, the class is
 223          * instantiated and the class name is replaced by te resulting singleton in $wgContentHandlers.
 224          *
 225          * If no ContentHandler is defined for the desired $modelId, the ContentHandler may be provided by the
 226          * a ContentHandlerForModelID hook. if no ContentHandler can be determined, an MWException is raised.
 227          *
 228          * @since WD.1
 229          *
 230          * @static
 231          * @param $modelId int the id of the content model for which to get a handler. Use CONTENT_MODEL_XXX constants.
 232          * @return ContentHandler the ContentHandler singleton for handling the model given by $modelId
 233          * @throws MWException if no handler is known for $modelId.
 234          */
 235         public static function getForModelID( $modelId ) {
 236                 global $wgContentHandlers;
 237
 238                 if ( empty( $wgContentHandlers[$modelId] ) ) {
 239                         $handler = null;
 240
 241                         wfRunHooks( 'ContentHandlerForModelID', array( $modelId, &$handler ) );
 242
 243                         if ( $handler ) { // NOTE: may be a string or an object, either is fine!
 244                                 $wgContentHandlers[$modelId] = $handler;
 245                         } else {
 246                                 throw new MWException( "No handler for model #$modelId registered in \$wgContentHandlers" );
 247                         }
 248                 }
 249
 250                 if ( is_string( $wgContentHandlers[$modelId] ) ) {
 251                         $class = $wgContentHandlers[$modelId];
 252                         $wgContentHandlers[$modelId] = new $class( $modelId );
 253                 }
 254
 255                 return $wgContentHandlers[$modelId];
 256         }
 257
 258         /**
 259          * Returns the appropriate mime type for a given content format,
 260          * or null if no mime type is known for this format.
 261          *
 262          * Mime types can be registered in the global array $wgContentFormatMimeTypes.
 263          *
 264          * @static
 265          * @param int $id the content format id, as given by a CONTENT_FORMAT_XXX constant
 266          *        or returned by Revision::getContentFormat().
 267          *
 268          * @return String|null the content format's mime type.
 269          */
 270         public static function getContentFormatMimeType( $id ) {
 271                 global $wgContentFormatMimeTypes;
 272
 273                 if ( !isset( $wgContentFormatMimeTypes[ $id ] ) ) {
 274                         return null;
 275                 }
 276
 277                 return $wgContentFormatMimeTypes[ $id ];
 278         }
 279
 280         /**
 281          * Returns the content format if for a given mime type,
 282          * or null if no format id if known for this mime type.
 283          *
 284          * Mime types can be registered in the global array $wgContentFormatMimeTypes.
 285          *
 286          * @static
 287          * @param String $mime the mime type
 288          *
 289          * @return int|null the format id, as defined by a CONTENT_FORMAT_XXX constant
 290          */
 291         public static function getContentFormatID( $mime ) {
 292                 global $wgContentFormatMimeTypes;
 293
 294                 static $format_ids = null;
 295
 296                 if ( $format_ids === null ) {
 297                         $format_ids = array_flip( $wgContentFormatMimeTypes );
 298                 }
 299
 300                 if ( !isset( $format_ids[ $mime ] ) ) {
 301                         return null;
 302                 }
 303
 304                 return $format_ids[ $mime ];
 305         }
 306
 307         /**
 308          * Returns the localized name for a given content model,
 309          * or null of no mime type is known.
 310          *
 311          * Model names are localized using system messages. Message keys
 312          * have the form content-model-$id.
 313          *
 314          * @static
 315          * @param int $id the content model id, as given by a CONTENT_MODEL_XXX constant
 316          *        or returned by Revision::getContentModel().
 317          *
 318          * @return String|null the content format's mime type.
 319          */
 320         public static function getContentModelName( $id ) {
 321                 $key = "content-model-$id";
 322
 323                 if ( wfEmptyMsg( $key ) ) return null;
 324                 else return wfMsg( $key );
 325         }
 326
 327         // ----------------------------------------------------------------------------------------------------------
 328
 329         protected $mModelID;
 330         protected $mSupportedFormats;
 331
 332         /**
 333          * Constructor, initializing the ContentHandler instance with it's model id and a list of supported formats.
 334          * Values for the parameters are typically provided as literals by subclasses' constructors.
 335          *
 336          * @param int $modelId (use CONTENT_MODEL_XXX constants).
 337          * @param array $formats list for supported serialization formats (typically as MIME types)
 338          */
 339         public function __construct( $modelId, $formats ) {
 340                 $this->mModelID = $modelId;
 341                 $this->mSupportedFormats = $formats;
 342         }
 343
 344
 345         /**
 346          * Serializes Content object of the type supported by this ContentHandler.
 347          *
 348          * @since WD.1
 349          *
 350          * @abstract
 351          * @param Content $content the Content object to serialize
 352          * @param null $format the desired serialization format
 353          * @return String serialized form of the content
 354          */
 355         public abstract function serializeContent( Content $content, $format = null );
 356
 357         /**
 358          * Unserializes a Content object of the type supported by this ContentHandler.
 359          *
 360          * @since WD.1
 361          *
 362          * @abstract
 363          * @param $blob String serialized form of the content
 364          * @param null $format the format used for serialization
 365          * @return Content the Content object created by deserializing $blob
 366          */
 367         public abstract function unserializeContent( $blob, $format = null );
 368
 369         /**
 370          * Creates an empty Content object of the type supported by this ContentHandler.
 371          *
 372          * @since WD.1
 373          *
 374          * @return Content
 375          */
 376         public abstract function makeEmptyContent();
 377
 378         /**
 379          * Returns the model id that identifies the content model this ContentHandler can handle.
 380          * Use with the CONTENT_MODEL_XXX constants.
 381          *
 382          * @since WD.1
 383          *
 384          * @return int the model id
 385          */
 386         public function getModelID() {
 387                 return $this->mModelID;
 388         }
 389
 390         /**
 391          * Throws an MWException if $model_id is not the id of the content model
 392          * supported by this ContentHandler.
 393          *
 394          * @since WD.1
 395          *
 396          * @param int $model_id the model to check
 397          *
 398          * @throws MWException
 399          */
 400         protected function checkModelID( $model_id ) {
 401                 if ( $model_id !== $this->mModelID ) {
 402                         $model_name = ContentHandler::getContentModelName( $model_id );
 403                         $own_model_name = ContentHandler::getContentModelName( $this->mModelID );
 404
 405                         throw new MWException( "Bad content model: expected {$this->mModelID} ($own_model_name) but got found $model_id ($model_name)." );
 406                 }
 407         }
 408
 409         /**
 410          * Returns a list of serialization formats supported by the serializeContent() and unserializeContent() methods of
 411          * this ContentHandler.
 412          *
 413          * @since WD.1
 414          *
 415          * @return array of serialization formats as MIME type like strings
 416          */
 417         public function getSupportedFormats() {
 418                 return $this->mSupportedFormats;
 419         }
 420
 421         /**
 422          * The format used for serialization/deserialization per default by this ContentHandler.
 423          *
 424          * This default implementation will return the first element of the array of formats
 425          * that was passed to the constructor.
 426          *
 427          * @since WD.1
 428          *
 429          * @return String the name of the default serialization format as a MIME type
 430          */
 431         public function getDefaultFormat() {
 432                 return $this->mSupportedFormats[0];
 433         }
 434
 435         /**
 436          * Returns true if $format is a serialization format supported by this ContentHandler,
 437          * and false otherwise.
 438          *
 439          * Note that if $format is null, this method always returns true, because null
 440          * means "use the default format".
 441          *
 442          * @since WD.1
 443          *
 444          * @param String $format the serialization format to check
 445          * @return bool
 446          */
 447         public function isSupportedFormat( $format ) {
 448
 449                 if ( !$format ) {
 450                         return true; // this means "use the default"
 451                 }
 452
 453                 return in_array( $format, $this->mSupportedFormats );
 454         }
 455
 456         /**
 457          * Throws an MWException if isSupportedFormat( $format ) is not true. Convenient
 458          * for checking whether a format provided as a parameter is actually supported.
 459          *
 460          * @param String $format the serialization format to check
 461          *
 462          * @throws MWException
 463          */
 464         protected function checkFormat( $format ) {
 465                 if ( !$this->isSupportedFormat( $format ) ) {
 466                         throw new MWException( "Format $format is not supported for content model " . $this->getModelID() );
 467                 }
 468         }
 469
 470         /**
 471          * Returns if the content is consistent with the database, that is if saving it to the database would not violate any
 472          * global constraints.
 473          *
 474          * Content needs to be valid using this method before it can be saved.
 475          *
 476          * This default implementation always returns true.
 477          *
 478          * @since WD.1
 479          *
 480          * @param \Content $content
 481          *
 482          * @return boolean
 483          */
 484         public function isConsistentWithDatabase( Content $content ) {
 485                 return true;
 486         }
 487
 488         /**
 489          * Returns overrides for action handlers.
 490          * Classes listed here will be used instead of the default one when
 491          * (and only when) $wgActions[$action] === true. This allows subclasses
 492          * to override the default action handlers.
 493          *
 494          * @since WD.1
 495          *
 496          * @return Array
 497          */
 498         public function getActionOverrides() {
 499                 return array();
 500         }
 501
 502         /**
 503          * Factory creating an appropriate DifferenceEngine for this content model.
 504          *
 505          * @since WD.1
 506          *
 507          * @param            $context      IContextSource context to use, anything else will be ignored
 508          * @param            $old          Integer old ID we want to show and diff with.
 509          * @param int|String $new          String either 'prev' or 'next'.
 510          * @param            $rcid         Integer ??? FIXME (default 0)
 511          * @param            $refreshCache boolean If set, refreshes the diff cache
 512          * @param            $unhide       boolean If set, allow viewing deleted revs
 513          *
 514          * @return DifferenceEngine
 515          */
 516         public function createDifferenceEngine( IContextSource $context, $old = 0, $new = 0, $rcid = 0, #FIMXE: use everywhere!
 517                                                                                  $refreshCache = false, $unhide = false ) {
 518
 519                 $this->checkModelID( $context->getTitle()->getContentModel() );
 520
 521                 $diffEngineClass = $this->getDiffEngineClass();
 522
 523                 return new $diffEngineClass( $context, $old, $new, $rcid, $refreshCache, $unhide );
 524         }
 525
 526         /**
 527          * Returns the name of the diff engine to use.
 528          *
 529          * @since WD.1
 530          *
 531          * @return string
 532          */
 533         protected function getDiffEngineClass() {
 534                 return 'DifferenceEngine';
 535         }
 536
 537         /**
 538          * attempts to merge differences between three versions.
 539          * Returns a new Content object for a clean merge and false for failure or a conflict.
 540          *
 541          * This default implementation always returns false.
 542          *
 543          * @since WD.1
 544          *
 545          * @param Content|String $oldContent  String
 546          * @param Content|String $myContent   String
 547          * @param Content|String $yourContent String
 548          *
 549          * @return Content|Bool
 550          */
 551         public function merge3( Content $oldContent, Content $myContent, Content $yourContent ) {
 552                 return false;
 553         }
 554
 555         /**
 556          * Return an applicable auto-summary if one exists for the given edit.
 557          *
 558          * @since WD.1
 559          *
 560          * @param $oldContent Content|null: the previous text of the page.
 561          * @param $newContent Content|null: The submitted text of the page.
 562          * @param $flags Int bit mask: a bit mask of flags submitted for the edit.
 563          *
 564          * @return string An appropriate auto-summary, or an empty string.
 565          */
 566         public function getAutosummary( Content $oldContent = null, Content $newContent = null, $flags ) {
 567                 global $wgContLang;
 568
 569                 // Decide what kind of auto-summary is needed.
 570
 571                 // Redirect auto-summaries
 572
 573                 /**
 574                  * @var $ot Title
 575                  * @var $rt Title
 576                  */
 577
 578                 $ot = !is_null( $oldContent ) ? $oldContent->getRedirectTarget() : null;
 579                 $rt = !is_null( $newContent ) ? $newContent->getRedirectTarget() : null;
 580
 581                 if ( is_object( $rt ) && ( !is_object( $ot ) || !$rt->equals( $ot ) || $ot->getFragment() != $rt->getFragment() ) ) {
 582
 583                         $truncatedtext = $newContent->getTextForSummary(
 584                                 250
 585                                         - strlen( wfMsgForContent( 'autoredircomment' ) )
 586                                         - strlen( $rt->getFullText() ) );
 587
 588                         return wfMsgForContent( 'autoredircomment', $rt->getFullText(), $truncatedtext );
 589                 }
 590
 591                 // New page auto-summaries
 592                 if ( $flags & EDIT_NEW && $newContent->getSize() > 0 ) {
 593                         // If they're making a new article, give its text, truncated, in the summary.
 594
 595                         $truncatedtext = $newContent->getTextForSummary(
 596                                 200 - strlen( wfMsgForContent( 'autosumm-new' ) ) );
 597
 598                         return wfMsgForContent( 'autosumm-new', $truncatedtext );
 599                 }
 600
 601                 // Blanking auto-summaries
 602                 if ( !empty( $oldContent ) && $oldContent->getSize() > 0 && $newContent->getSize() == 0 ) {
 603                         return wfMsgForContent( 'autosumm-blank' );
 604                 } elseif ( !empty( $oldContent ) && $oldContent->getSize() > 10 * $newContent->getSize() && $newContent->getSize() < 500 ) {
 605                         // Removing more than 90% of the article
 606
 607                         $truncatedtext = $newContent->getTextForSummary(
 608                                 200 - strlen( wfMsgForContent( 'autosumm-replace' ) ) );
 609
 610                         return wfMsgForContent( 'autosumm-replace', $truncatedtext );
 611                 }
 612
 613                 // If we reach this point, there's no applicable auto-summary for our case, so our
 614                 // auto-summary is empty.
 615
 616                 return '';
 617         }
 618
 619         /**
 620          * Auto-generates a deletion reason
 621          *
 622          * @since WD.1
 623          *
 624          * @param $title Title: the page's title
 625          * @param &$hasHistory Boolean: whether the page has a history
 626          * @return mixed String containing deletion reason or empty string, or boolean false
 627          *    if no revision occurred
 628          *
 629          * @XXX &$hasHistory is extremely ugly, it's here because WikiPage::getAutoDeleteReason() and Article::getReason() have it / want it.
 630          */
 631         public function getAutoDeleteReason( Title $title, &$hasHistory ) {
 632                 $dbw = wfGetDB( DB_MASTER );
 633
 634                 // Get the last revision
 635                 $rev = Revision::newFromTitle( $title );
 636
 637                 if ( is_null( $rev ) ) {
 638                         return false;
 639                 }
 640
 641                 // Get the article's contents
 642                 $content = $rev->getContent();
 643                 $blank = false;
 644
 645                 // If the page is blank, use the text from the previous revision,
 646                 // which can only be blank if there's a move/import/protect dummy revision involved
 647                 if ( $content->getSize() == 0 ) {
 648                         $prev = $rev->getPrevious();
 649
 650                         if ( $prev )    {
 651                                 $content = $rev->getContent();
 652                                 $blank = true;
 653                         }
 654                 }
 655
 656                 // Find out if there was only one contributor
 657                 // Only scan the last 20 revisions
 658                 $res = $dbw->select( 'revision', 'rev_user_text',
 659                         array( 'rev_page' => $title->getArticleID(), $dbw->bitAnd( 'rev_deleted', Revision::DELETED_USER ) . ' = 0' ),
 660                         __METHOD__,
 661                         array( 'LIMIT' => 20 )
 662                 );
 663
 664                 if ( $res === false ) {
 665                         // This page has no revisions, which is very weird
 666                         return false;
 667                 }
 668
 669                 $hasHistory = ( $res->numRows() > 1 );
 670                 $row = $dbw->fetchObject( $res );
 671
 672                 if ( $row ) { // $row is false if the only contributor is hidden
 673                         $onlyAuthor = $row->rev_user_text;
 674                         // Try to find a second contributor
 675                         foreach ( $res as $row ) {
 676                                 if ( $row->rev_user_text != $onlyAuthor ) { // Bug 22999
 677                                         $onlyAuthor = false;
 678                                         break;
 679                                 }
 680                         }
 681                 } else {
 682                         $onlyAuthor = false;
 683                 }
 684
 685                 // Generate the summary with a '$1' placeholder
 686                 if ( $blank ) {
 687                         // The current revision is blank and the one before is also
 688                         // blank. It's just not our lucky day
 689                         $reason = wfMsgForContent( 'exbeforeblank', '$1' );
 690                 } else {
 691                         if ( $onlyAuthor ) {
 692                                 $reason = wfMsgForContent( 'excontentauthor', '$1', $onlyAuthor );
 693                         } else {
 694                                 $reason = wfMsgForContent( 'excontent', '$1' );
 695                         }
 696                 }
 697
 698                 if ( $reason == '-' ) {
 699                         // Allow these UI messages to be blanked out cleanly
 700                         return '';
 701                 }
 702
 703                 // Max content length = max comment length - length of the comment (excl. $1)
 704                 $text = $content->getTextForSummary( 255 - ( strlen( $reason ) - 2 ) );
 705
 706                 // Now replace the '$1' placeholder
 707                 $reason = str_replace( '$1', $text, $reason );
 708
 709                 return $reason;
 710         }
 711
 712         #@TODO: getSecondaryUpdatesForDeletion( Content ) returns an array of DataUpdate objects
 713         #... or do that in the Content class?
 714
 715         /**
 716          * Get the Content object that needs to be saved in order to undo all revisions
 717          * between $undo and $undoafter. Revisions must belong to the same page,
 718          * must exist and must not be deleted
 719          *
 720          * @since WD.1
 721          *
 722          * @param $current Revision the current text
 723          * @param $undo Revision the revision to undo
 724          * @param $undoafter Revision Must be an earlier revision than $undo
 725          *
 726          * @return mixed string on success, false on failure
 727          */
 728         public function getUndoContent( Revision $current, Revision $undo, Revision $undoafter ) {
 729                 $cur_content = $current->getContent();
 730
 731                 if ( empty( $cur_content ) ) {
 732                         return false; // no page
 733                 }
 734
 735                 $undo_content = $undo->getContent();
 736                 $undoafter_content = $undoafter->getContent();
 737
 738                 if ( $cur_content->equals( $undo_content ) ) {
 739                         // No use doing a merge if it's just a straight revert.
 740                         return $undoafter_content;
 741                 }
 742
 743                 $undone_content = $this->merge3( $undo_content, $undoafter_content, $cur_content );
 744
 745                 return $undone_content;
 746         }
 747
 748         /**
 749          * Returns true for content models that support caching using the ParserCache mechanism.
 750          * See WikiPage::isParserCacheUser().
 751          *
 752          * @since WD.1
 753          *
 754          * @return bool
 755          */
 756         public function isParserCacheSupported() {
 757                 return true;
 758         }
 759
 760         /**
 761          * @since WD.1
 762          *
 763          * @param $page WikiPage the page that was deleted (note: $page->getId() must still return the old page ID!)
 764          *
 765          * @return array a list of DataUpdate instances that will clean up the database ofter deletion.
 766          */
 767         public function getDeletionUpdates( WikiPage $page ) {
 768                 return array(
 769                         new LinksDeletionUpdate( $page ),
 770                 );
 771         }
 772 }
 773
 774 /**
 775  * @since WD.1
 776  */
 777 abstract class TextContentHandler extends ContentHandler {
 778
 779         public function __construct( $modelId, $formats ) {
 780                 parent::__construct( $modelId, $formats );
 781         }
 782
 783         /**
 784          * Returns the content's text as-is.
 785          *
 786          * @param Content $content
 787          * @param String|null $format
 788          * @return mixed
 789          */
 790         public function serializeContent( Content $content, $format = null ) {
 791                 $this->checkFormat( $format );
 792                 return $content->getNativeData();
 793         }
 794
 795         /**
 796          * attempts to merge differences between three versions.
 797          * Returns a new Content object for a clean merge and false for failure or a conflict.
 798          *
 799          * All three Content objects passed as parameters must have the same content model.
 800          *
 801          * This text-based implementation uses wfMerge().
 802          *
 803          * @param \Content|String $oldContent  String
 804          * @param \Content|String $myContent   String
 805          * @param \Content|String $yourContent String
 806          *
 807          * @return Content|Bool
 808          */
 809         public function merge3( Content $oldContent, Content $myContent, Content $yourContent ) {
 810                 $this->checkModelID( $oldContent->getModel() );
 811                 $this->checkModelID( $myContent->getModel() );
 812                 $this->checkModelID( $yourContent->getModel() );
 813
 814                 $format = $this->getDefaultFormat();
 815
 816                 $old = $this->serializeContent( $oldContent, $format );
 817                 $mine = $this->serializeContent( $myContent, $format );
 818                 $yours = $this->serializeContent( $yourContent, $format );
 819
 820                 $ok = wfMerge( $old, $mine, $yours, $result );
 821
 822                 if ( !$ok ) {
 823                         return false;
 824                 }
 825
 826                 if ( !$result ) {
 827                         return $this->makeEmptyContent();
 828                 }
 829
 830                 $mergedContent = $this->unserializeContent( $result, $format );
 831                 return $mergedContent;
 832         }
 833
 834
 835 }
 836
 837 /**
 838  * @since WD.1
 839  */
 840 class WikitextContentHandler extends TextContentHandler {
 841
 842         public function __construct( $modelId = CONTENT_MODEL_WIKITEXT ) {
 843                 parent::__construct( $modelId, array( CONTENT_FORMAT_WIKITEXT ) );
 844         }
 845
 846         public function unserializeContent( $text, $format = null ) {
 847                 $this->checkFormat( $format );
 848
 849                 return new WikitextContent( $text );
 850         }
 851
 852         public function makeEmptyContent() {
 853                 return new WikitextContent( '' );
 854         }
 855
 856
 857 }
 858
 859 #XXX: make ScriptContentHandler base class with plugin interface for syntax highlighting?
 860
 861 /**
 862  * @since WD.1
 863  */
 864 class JavaScriptContentHandler extends TextContentHandler {
 865
 866         public function __construct( $modelId = CONTENT_MODEL_JAVASCRIPT ) {
 867                 parent::__construct( $modelId, array( CONTENT_FORMAT_JAVASCRIPT ) );
 868         }
 869
 870         public function unserializeContent( $text, $format = null ) {
 871                 $this->checkFormat( $format );
 872
 873                 return new JavaScriptContent( $text );
 874         }
 875
 876         public function makeEmptyContent() {
 877                 return new JavaScriptContent( '' );
 878         }
 879 }
 880
 881 /**
 882  * @since WD.1
 883  */
 884 class CssContentHandler extends TextContentHandler {
 885
 886         public function __construct( $modelId = CONTENT_MODEL_CSS ) {
 887                 parent::__construct( $modelId, array( CONTENT_FORMAT_CSS ) );
 888         }
 889
 890         public function unserializeContent( $text, $format = null ) {
 891                 $this->checkFormat( $format );
 892
 893                 return new CssContent( $text );
 894         }
 895
 896         public function makeEmptyContent() {
 897                 return new CssContent( '' );
 898         }
 899
 900 }