includes/ContentHandler.php

   1 <?php
   2
   3 class MWContentSerializationException extends MWException {
   4
   5 }
   6
   7
   8 /**
   9  * A content handler knows how do deal with a specific type of content on a wiki page.
  10  * Content is stored in the database in a serialized form (using a serialization format aka mime type)
  11  * and is be unserialized into it's native PHP represenation (the content model), which is wrappe in
  12  * an instance of the appropriate subclass of Content.
  13  *
  14  * ContentHandler instances are stateless singletons that serve, among other things, as a factory for
  15  * Content objects. Generally, there is one subclass of ContentHandler and one subclass of Content
  16  * for every type of content model.
  17  *
  18  * Some content types have a flat model, that is, their native represenation is the
  19  * same as their serialized form. Examples would be JavaScript and CSS code. As of now,
  20  * this also applies to wikitext (mediawiki's default content type), but wikitext
  21  * content may be represented by a DOM or AST structure in the future.
  22  *
  23  * @since 1.WD
  24  */
  25 abstract class ContentHandler {
  26
  27         /**
  28          * Conveniance function for getting flat text from a Content object. This should only
  29          * be used in the context of backwards compatibility with code that is not yet able
  30          * to handle Content objects!
  31          *
  32          * If $content is null, this method returns the empty string.
  33          *
  34          * If $content is an instance of TextContent, this method returns the flat text as returned by $content->getNativeData().
  35          *
  36          * If $content is not a TextContent object, the bahaviour of this method depends on the global $wgContentHandlerTextFallback:
  37          * * If $wgContentHandlerTextFallback is 'fail' and $content is not a TextContent object, an MWException is thrown.
  38          * * If $wgContentHandlerTextFallback is 'serialize' and $content is not a TextContent object, $content->serialize()
  39          * is called to get a string form of the content.
  40          * * If $wgContentHandlerTextFallback is 'ignore' and $content is not a TextContent object, this method returns null.
  41          * * otherwise, the behaviour is undefined.
  42          *
  43          * @since WD.1
  44          *
  45          * @static
  46          * @param Content|null $content
  47          * @return null|string the textual form of $content, if available
  48          * @throws MWException if $content is not an instance of TextContent and $wgContentHandlerTextFallback was set to 'fail'.
  49          */
  50         public static function getContentText( Content $content = null ) {
  51                 global $wgContentHandlerTextFallback;
  52
  53                 if ( is_null( $content ) ) {
  54                         return '';
  55                 }
  56
  57                 if ( $content instanceof TextContent ) {
  58                         return $content->getNativeData();
  59                 }
  60
  61                 if ( $wgContentHandlerTextFallback == 'fail' ) {
  62                         throw new MWException( "Attempt to get text from Content with model " . $content->getModelName() );
  63                 }
  64
  65                 if ( $wgContentHandlerTextFallback == 'serialize' ) {
  66                         return $content->serialize();
  67                 }
  68
  69                 return null;
  70         }
  71
  72         /**
  73          * Conveniance function for creating a Content object from a given textual representation.
  74          *
  75          * $text will be deserialized into a Content object of the model specified by $modelName (or,
  76          * if that is not given, $title->getContentModelName()) using the given format.
  77          *
  78          * @since WD.1
  79          *
  80          * @static
  81          * @param string $text the textual represenation, will be unserialized to create the Content object
  82          * @param Title $title the title of the page this text belongs to, required as a context for deserialization
  83          * @param null|String $modelName the model to deserialize to. If not provided, $title->getContentModelName() is used.
  84          * @param null|String $format the format to use for deserialization. If not given, the model's default format is used.
  85          *
  86          * @return Content a Content object representing $text
  87          * @throw MWException if $model or $format is not supported or if $text can not be unserialized using $format.
  88          */
  89         public static function makeContent( $text, Title $title, $modelName = null, $format = null ) {
  90
  91                 if ( is_null( $modelName ) ) {
  92                         $modelName = $title->getContentModelName();
  93                 }
  94
  95                 $handler = ContentHandler::getForModelName( $modelName );
  96                 return $handler->unserializeContent( $text, $format );
  97         }
  98
  99         /**
 100          * Returns the name of the default content model to be used for the page with the given title.
 101          *
 102          * Note: There should rarely be need to call this method directly.
 103          * To determine the actual content model for a given page, use Title::getContentModelName().
 104          *
 105          * Which model is to be used per default for the page is determined based on several factors:
 106          * * The global setting $wgNamespaceContentModels specifies a content model per namespace.
 107          * * The hook DefaultModelFor may be used to override the page's default model.
 108          * * Pages in NS_MEDIAWIKI and NS_USER default to the CSS or JavaScript model if they end in .js or .css, respectively.
 109          * * Pages in NS_MEDIAWIKI default to the wikitext model otherwise.
 110          * * 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.
 111          * * The hook TitleIsWikitextPage may be used to force a page to use the wikitext model.
 112          *
 113          * If none of the above applies, the wikitext model is used.
 114          *
 115          * Note: this is used by, and may thus not use, Title::getContentModelName()
 116          *
 117          * @since WD.1
 118          *
 119          * @static
 120          * @param Title $title
 121          * @return null|string default model name for the page given by $title
 122          */
 123         public static function getDefaultModelFor( Title $title ) {
 124                 global $wgNamespaceContentModels;
 125
 126                 // NOTE: this method must not rely on $title->getContentModelName() directly or indirectly,
 127                 //       because it is used to initialized the mContentModelName memebr.
 128
 129                 $ns = $title->getNamespace();
 130
 131                 $ext = false;
 132                 $m = null;
 133                 $model = null;
 134
 135                 if ( !empty( $wgNamespaceContentModels[ $ns ] ) ) {
 136                         $model = $wgNamespaceContentModels[ $ns ];
 137                 }
 138
 139                 // hook can determin default model
 140                 if ( !wfRunHooks( 'ContentHandlerDefaultModelFor', array( $title, &$model ) ) ) {
 141                         if ( !is_null( $model ) ) {
 142                                 return $model;
 143                         }
 144                 }
 145
 146                 // Could this page contain custom CSS or JavaScript, based on the title?
 147                 $isCssOrJsPage = NS_MEDIAWIKI == $ns && preg_match( '!\.(css|js)$!u', $title->getText(), $m );
 148                 if ( $isCssOrJsPage ) {
 149                         $ext = $m[1];
 150                 }
 151
 152                 // hook can force js/css
 153                 wfRunHooks( 'TitleIsCssOrJsPage', array( $title, &$isCssOrJsPage ) );
 154
 155                 // Is this a .css subpage of a user page?
 156                 $isJsCssSubpage = NS_USER == $ns && !$isCssOrJsPage && preg_match( "/\\/.*\\.(js|css)$/", $title->getText(), $m );
 157                 if ( $isJsCssSubpage ) {
 158                         $ext = $m[1];
 159                 }
 160
 161                 // is this wikitext, according to $wgNamespaceContentModels or the DefaultModelFor hook?
 162                 $isWikitext = is_null( $model ) || $model == CONTENT_MODEL_WIKITEXT;
 163                 $isWikitext = $isWikitext && !$isCssOrJsPage && !$isJsCssSubpage;
 164
 165                 // hook can override $isWikitext
 166                 wfRunHooks( 'TitleIsWikitextPage', array( $title, &$isWikitext ) );
 167
 168                 if ( !$isWikitext ) {
 169                         switch ( $ext ) {
 170                                 case 'js':
 171                                         return CONTENT_MODEL_JAVASCRIPT;
 172                                 case 'css':
 173                                         return CONTENT_MODEL_CSS;
 174                                 default:
 175                                         return is_null( $model ) ? CONTENT_MODEL_TEXT : $model;
 176                         }
 177                 }
 178
 179                 // we established that is must be wikitext
 180
 181                 return CONTENT_MODEL_WIKITEXT;
 182         }
 183
 184         /**
 185          * returns the appropriate ContentHandler singleton for the given title
 186          *
 187          * @since WD.1
 188          *
 189          * @static
 190          * @param Title $title
 191          * @return ContentHandler
 192          */
 193         public static function getForTitle( Title $title ) {
 194                 $modelName = $title->getContentModelName();
 195                 return ContentHandler::getForModelName( $modelName );
 196         }
 197
 198         /**
 199          * returns the appropriate ContentHandler singleton for the given Content object
 200          *
 201          * @since WD.1
 202          *
 203          * @static
 204          * @param Content $content
 205          * @return ContentHandler
 206          */
 207         public static function getForContent( Content $content ) {
 208                 $modelName = $content->getModelName();
 209                 return ContentHandler::getForModelName( $modelName );
 210         }
 211
 212         /**
 213          * returns the ContentHandler singleton for the given model name. Use the CONTENT_MODEL_XXX constants to
 214          * identify the desired content model.
 215          *
 216          * ContentHandler singletons are take from the global $wgContentHandlers array. Keys in that array are
 217          * model names, the values are either ContentHandler singleton objects, or strings specifying the appropriate
 218          * subclass of ContentHandler.
 219          *
 220          * If a class name in encountered when looking up the singleton for a given model name, the class is
 221          * instantiated and the class name is replaced by te resulting singleton in $wgContentHandlers.
 222          *
 223          * If no ContentHandler is defined for the desired $modelName, the ContentHandler may be provided by the
 224          * a ContentHandlerForModelName hook. if no Contenthandler can be determined, an MWException is raised.
 225          *
 226          * @since WD.1
 227          *
 228          * @static
 229          * @param $modelName String the name of the content model for which to get a handler. Use CONTENT_MODEL_XXX constants.
 230          * @return ContentHandler the ContentHandler singleton for handling the model given by $modelName
 231          * @throws MWException if no handler is known for $modelName.
 232          */
 233         public static function getForModelName( $modelName ) {
 234                 global $wgContentHandlers;
 235
 236                 if ( empty( $wgContentHandlers[$modelName] ) ) {
 237                         $handler = null;
 238
 239                         wfRunHooks( 'ContentHandlerForModelName', array( $modelName, &$handler ) );
 240
 241                         if ( $handler ) { // NOTE: may be a string or an object, either is fine!
 242                                 $wgContentHandlers[$modelName] = $handler;
 243                         } else {
 244                                 throw new MWException( "No handler for model $modelName registered in \$wgContentHandlers" );
 245                         }
 246                 }
 247
 248                 if ( is_string( $wgContentHandlers[$modelName] ) ) {
 249                         $class = $wgContentHandlers[$modelName];
 250                         $wgContentHandlers[$modelName] = new $class( $modelName );
 251                 }
 252
 253                 return $wgContentHandlers[$modelName];
 254         }
 255
 256         // ----------------------------------------------------------------------------------------------------------
 257
 258         /**
 259          * Constructor, initializing the ContentHandler instance with it's model name and a list of supported formats.
 260          * Values for the parameters are typically provided as literals by subclasses' constructors.
 261          *
 262          * @param String $modelName (use CONTENT_MODEL_XXX constants).
 263          * @param array $formats list for supported serialization formats (typically as MIME types)
 264          */
 265         public function __construct( $modelName, $formats ) {
 266                 $this->mModelName = $modelName;
 267                 $this->mSupportedFormats = $formats;
 268         }
 269
 270
 271         /**
 272          * Serializes Content object of the type supported by this ContentHandler.
 273          *
 274          * @since WD.1
 275          *
 276          * @abstract
 277          * @param Content $content the Content object to serialize
 278          * @param null $format the desired serialization format
 279          * @return String serialized form of the content
 280          */
 281         public abstract function serializeContent( Content $content, $format = null );
 282
 283         /**
 284          * Unserializes a Content object of the type supported by this ContentHandler.
 285          *
 286          * @since WD.1
 287          *
 288          * @abstract
 289          * @param $blob String serialized form of the content
 290          * @param null $format the format used for serialization
 291          * @return Content the Content object created by deserializing $blob
 292          */
 293         public abstract function unserializeContent( $blob, $format = null );
 294
 295         /**
 296          * Creates an empty Content object of the type supported by this ContentHandler.
 297          *
 298          * @since WD.1
 299          *
 300          * @return Content
 301          */
 302         public abstract function makeEmptyContent();
 303
 304         /**
 305          * Returns the model name that identifies the content model this ContentHandler can handle.
 306          * Use with the CONTENT_MODEL_XXX constants.
 307          *
 308          * @since WD.1
 309          *
 310          * @return String the model name
 311          */
 312         public function getModelName() {
 313                 return $this->mModelName;
 314         }
 315
 316         /**
 317          * Throws an MWException if $modelName is not the content model handeled by this ContentHandler.
 318          *
 319          * @since WD.1
 320          *
 321          * @param String $modelName the model name to check
 322          */
 323         protected function checkModelName( $modelName ) {
 324                 if ( $modelName !== $this->mModelName ) {
 325                         throw new MWException( "Bad content model: expected " . $this->mModelName . " but got found " . $modelName );
 326                 }
 327         }
 328
 329         /**
 330          * Returns a list of serialization formats supported by the serializeContent() and unserializeContent() methods of
 331          * this ContentHandler.
 332          *
 333          * @since WD.1
 334          *
 335          * @return array of serialization formats as MIME type like strings
 336          */
 337         public function getSupportedFormats() {
 338                 return $this->mSupportedFormats;
 339         }
 340
 341         /**
 342          * The format used for serialization/deserialization per default by this ContentHandler.
 343          *
 344          * This default implementation will return the first element of the array of formats
 345          * that was passed to the constructor.
 346          *
 347          * @since WD.1
 348          *
 349          * @return String the name of the default serialiozation format as a MIME type
 350          */
 351         public function getDefaultFormat() {
 352                 return $this->mSupportedFormats[0];
 353         }
 354
 355         /**
 356          * Returns true if $format is a serialization format supported by this ContentHandler,
 357          * and false otherwise.
 358          *
 359          * Note that if $format is null, this method always returns true, because null
 360          * means "use the default format".
 361          *
 362          * @since WD.1
 363          *
 364          * @param String $format the serialization format to check
 365          * @return bool
 366          */
 367         public function isSupportedFormat( $format ) {
 368
 369                 if ( !$format ) {
 370                         return true; // this means "use the default"
 371                 }
 372
 373                 return in_array( $format, $this->mSupportedFormats );
 374         }
 375
 376         /**
 377          * Throws an MWException if isSupportedFormat( $format ) is not true. Convenient
 378          * for checking whether a format provided as a parameter is actually supported.
 379          *
 380          * @param String $format the serialization format to check
 381          */
 382         protected function checkFormat( $format ) {
 383                 if ( !$this->isSupportedFormat( $format ) ) {
 384                         throw new MWException( "Format $format is not supported for content model " . $this->getModelName() );
 385                 }
 386         }
 387
 388         /**
 389          * Returns overrides for action handlers.
 390          * Classes listed here will be used instead of the default one when
 391          * (and only when) $wgActions[$action] === true. This allows subclasses
 392          * to override the default action handlers.
 393          *
 394          * @since WD.1
 395          *
 396          * @return Array
 397          */
 398         public function getActionOverrides() {
 399                 return array();
 400         }
 401
 402         /**
 403          * Return an Article object suitable for viewing the given object
 404          *
 405          * NOTE: does *not* do special handling for Image and Category pages!
 406          *       Use Article::newFromTitle() for that!
 407          *
 408          * @since WD.1
 409          *
 410          * @param Title $title
 411          * @return Article
 412          * @todo Article is being refactored into an action class, keep track of that
 413          * @todo Article really defines the view of the content... rename this method to createViewPage ?
 414          */
 415         public function createArticle( Title $title ) {
 416                 $this->checkModelName( $title->getContentModelName() );
 417
 418                 $article = new Article($title);
 419                 return $article;
 420         }
 421
 422         /**
 423          * Return an EditPage object suitable for editing the given object
 424          *
 425          * @since WD.1
 426          *
 427          * @param Article $article
 428          * @return EditPage
 429          */
 430         public function createEditPage( Article $article ) {
 431                 $this->checkModelName( $article->getContentModelName() );
 432
 433                 $editPage = new EditPage( $article );
 434                 return $editPage;
 435         }
 436
 437         /**
 438          * Return an ExternalEdit object suitable for editing the given object
 439          *
 440          * @since WD.1
 441          *
 442          * @param IContextSource $context
 443          * @return ExternalEdit
 444          * @todo does anyone or anythign actually use the external edit facility? Can we just deprecate and ignore it?
 445          */
 446         public function createExternalEdit( IContextSource $context ) {
 447                 $this->checkModelName( $context->getTitle()->getContentModelName() );
 448
 449                 $externalEdit = new ExternalEdit( $context );
 450                 return $externalEdit;
 451         }
 452
 453         /**
 454          * Factory
 455          * @since WD.1
 456          *
 457          * @param $context IContextSource context to use, anything else will be ignored
 458          * @param $old Integer old ID we want to show and diff with.
 459          * @param $new String either 'prev' or 'next'.
 460          * @param $rcid Integer ??? FIXME (default 0)
 461          * @param $refreshCache boolean If set, refreshes the diff cache
 462          * @param $unhide boolean If set, allow viewing deleted revs
 463          *
 464          * @return DifferenceEngine
 465          */
 466         public function createDifferenceEngine( IContextSource $context, $old = 0, $new = 0, $rcid = 0, #FIMXE: use everywhere!
 467                                                                                  $refreshCache = false, $unhide = false ) {
 468
 469                 $this->checkModelName( $context->getTitle()->getContentModelName() );
 470
 471                 $diffEngineClass = $this->getDiffEngineClass();
 472
 473                 return new $diffEngineClass( $context, $old, $new, $rcid, $refreshCache, $unhide );
 474         }
 475
 476         /**
 477          * Returns the name of the diff engine to use.
 478          *
 479          * @since WD.1
 480          *
 481          * @return string
 482          */
 483         protected function getDiffEngineClass() {
 484                 return 'DifferenceEngine';
 485         }
 486
 487         /**
 488          * attempts to merge differences between three versions.
 489          * Returns a new Content object for a clean merge and false for failure or a conflict.
 490          *
 491          * This default implementation always returns false.
 492          *
 493          * @since WD.1
 494          *
 495          * @param $oldContent String
 496          * @param $myContent String
 497          * @param $yourContent String
 498          * @return Content|Bool
 499          */
 500         public function merge3( Content $oldContent, Content $myContent, Content $yourContent ) {
 501                 return false;
 502         }
 503
 504         /**
 505          * Return an applicable autosummary if one exists for the given edit.
 506          *
 507          * @since WD.1
 508          *
 509          * @param $oldContent Content|null: the previous text of the page.
 510          * @param $newContent Content|null: The submitted text of the page.
 511          * @param $flags Int bitmask: a bitmask of flags submitted for the edit.
 512          *
 513          * @return string An appropriate autosummary, or an empty string.
 514          */
 515         public function getAutosummary( Content $oldContent = null, Content $newContent = null, $flags ) {
 516                 global $wgContLang;
 517
 518                 // Decide what kind of autosummary is needed.
 519
 520                 // Redirect autosummaries
 521
 522                 /**
 523                  * @var $ot Title
 524                  * @var $rt Title
 525                  */
 526
 527                 $ot = !is_null( $oldContent ) ? $oldContent->getRedirectTarget() : null;
 528                 $rt = !is_null( $newContent ) ? $newContent->getRedirectTarget() : null;
 529
 530                 if ( is_object( $rt ) && ( !is_object( $ot ) || !$rt->equals( $ot ) || $ot->getFragment() != $rt->getFragment() ) ) {
 531
 532                         $truncatedtext = $newContent->getTextForSummary(
 533                                 250
 534                                         - strlen( wfMsgForContent( 'autoredircomment' ) )
 535                                         - strlen( $rt->getFullText() ) );
 536
 537                         return wfMsgForContent( 'autoredircomment', $rt->getFullText(), $truncatedtext );
 538                 }
 539
 540                 // New page autosummaries
 541                 if ( $flags & EDIT_NEW && $newContent->getSize() > 0 ) {
 542                         // If they're making a new article, give its text, truncated, in the summary.
 543
 544                         $truncatedtext = $newContent->getTextForSummary(
 545                                 200 - strlen( wfMsgForContent( 'autosumm-new' ) ) );
 546
 547                         return wfMsgForContent( 'autosumm-new', $truncatedtext );
 548                 }
 549
 550                 // Blanking autosummaries
 551                 if ( !empty( $oldContent ) && $oldContent->getSize() > 0 && $newContent->getSize() == 0 ) {
 552                         return wfMsgForContent( 'autosumm-blank' );
 553                 } elseif ( !empty( $oldContent ) && $oldContent->getSize() > 10 * $newContent->getSize() && $newContent->getSize() < 500 ) {
 554                         // Removing more than 90% of the article
 555
 556                         $truncatedtext = $newContent->getTextForSummary(
 557                                 200 - strlen( wfMsgForContent( 'autosumm-replace' ) ) );
 558
 559                         return wfMsgForContent( 'autosumm-replace', $truncatedtext );
 560                 }
 561
 562                 // If we reach this point, there's no applicable autosummary for our case, so our
 563                 // autosummary is empty.
 564
 565                 return '';
 566         }
 567
 568         /**
 569          * Auto-generates a deletion reason
 570          *
 571          * @since WD.1
 572          *
 573          * @param $title Title: the page's title
 574          * @param &$hasHistory Boolean: whether the page has a history
 575          * @return mixed String containing deletion reason or empty string, or boolean false
 576          *    if no revision occurred
 577          *
 578          * @XXX &$hasHistory is extremely ugly, it's here because WikiPage::getAutoDeleteReason() and Article::getReason() have it / want it.
 579          */
 580         public function getAutoDeleteReason( Title $title, &$hasHistory ) {
 581                 $dbw = wfGetDB( DB_MASTER );
 582
 583                 // Get the last revision
 584                 $rev = Revision::newFromTitle( $title );
 585
 586                 if ( is_null( $rev ) ) {
 587                         return false;
 588                 }
 589
 590                 // Get the article's contents
 591                 $content = $rev->getContent();
 592                 $blank = false;
 593
 594                 // If the page is blank, use the text from the previous revision,
 595                 // which can only be blank if there's a move/import/protect dummy revision involved
 596                 if ( $content->getSize() == 0 ) {
 597                         $prev = $rev->getPrevious();
 598
 599                         if ( $prev )    {
 600                                 $content = $rev->getContent();
 601                                 $blank = true;
 602                         }
 603                 }
 604
 605                 // Find out if there was only one contributor
 606                 // Only scan the last 20 revisions
 607                 $res = $dbw->select( 'revision', 'rev_user_text',
 608                         array( 'rev_page' => $title->getArticleID(), $dbw->bitAnd( 'rev_deleted', Revision::DELETED_USER ) . ' = 0' ),
 609                         __METHOD__,
 610                         array( 'LIMIT' => 20 )
 611                 );
 612
 613                 if ( $res === false ) {
 614                         // This page has no revisions, which is very weird
 615                         return false;
 616                 }
 617
 618                 $hasHistory = ( $res->numRows() > 1 );
 619                 $row = $dbw->fetchObject( $res );
 620
 621                 if ( $row ) { // $row is false if the only contributor is hidden
 622                         $onlyAuthor = $row->rev_user_text;
 623                         // Try to find a second contributor
 624                         foreach ( $res as $row ) {
 625                                 if ( $row->rev_user_text != $onlyAuthor ) { // Bug 22999
 626                                         $onlyAuthor = false;
 627                                         break;
 628                                 }
 629                         }
 630                 } else {
 631                         $onlyAuthor = false;
 632                 }
 633
 634                 // Generate the summary with a '$1' placeholder
 635                 if ( $blank ) {
 636                         // The current revision is blank and the one before is also
 637                         // blank. It's just not our lucky day
 638                         $reason = wfMsgForContent( 'exbeforeblank', '$1' );
 639                 } else {
 640                         if ( $onlyAuthor ) {
 641                                 $reason = wfMsgForContent( 'excontentauthor', '$1', $onlyAuthor );
 642                         } else {
 643                                 $reason = wfMsgForContent( 'excontent', '$1' );
 644                         }
 645                 }
 646
 647                 if ( $reason == '-' ) {
 648                         // Allow these UI messages to be blanked out cleanly
 649                         return '';
 650                 }
 651
 652                 // Max content length = max comment length - length of the comment (excl. $1)
 653                 $text = $content->getTextForSummary( 255 - ( strlen( $reason ) - 2 ) );
 654
 655                 // Now replace the '$1' placeholder
 656                 $reason = str_replace( '$1', $text, $reason );
 657
 658                 return $reason;
 659         }
 660
 661         #@TODO: getSecondaryUpdatesForDeletion( Content ) returns an array of SecondaryDataUpdate objects
 662         #... or do that in the Content class?
 663
 664         /**
 665          * Get the Content object that needs to be saved in order to undo all revisions
 666          * between $undo and $undoafter. Revisions must belong to the same page,
 667          * must exist and must not be deleted
 668          *
 669          * @since WD.1
 670          *
 671          * @param $current Revision the current text
 672          * @param $undo Revision the revision to undo
 673          * @param $undoafter Revision Must be an earlier revision than $undo
 674          *
 675          * @return mixed string on success, false on failure
 676          */
 677         public function getUndoContent( Revision $current, Revision $undo, Revision $undoafter ) {
 678                 $cur_content = $current->getContent();
 679
 680                 if ( empty( $cur_content ) ) {
 681                         return false; // no page
 682                 }
 683
 684                 $undo_content = $undo->getContent();
 685                 $undoafter_content = $undoafter->getContent();
 686
 687                 if ( $cur_content->equals( $undo_content ) ) {
 688                         // No use doing a merge if it's just a straight revert.
 689                         return $undoafter_content;
 690                 }
 691
 692                 $undone_content = $this->merge3( $undo_content, $undoafter_content, $cur_content );
 693
 694                 return $undone_content;
 695         }
 696
 697         /**
 698          * Returns true for content models that support caching using the ParserCache mechanism.
 699          * See WikiPage::isParserCacheUser().
 700          *
 701          * @since WD.1
 702          *
 703          * @return bool
 704          */
 705         public function isParserCacheSupported() {
 706                 return true;
 707         }
 708
 709         /**
 710          * @since WD.1
 711          *
 712          * @param $page WikiPage the page that was deleted (note: $page->getId() must still return the old page ID!)
 713          *
 714          * @return array a list of SecondaryDataUpdate instances that will clean up the database ofter deletion.
 715          */
 716         public function getDeletionUpdates( WikiPage $page ) {
 717                 return array(
 718                         new LinksDeletionUpdate( $page ),
 719                 );
 720         }
 721 }
 722
 723 /**
 724  * @since WD.1
 725  */
 726 abstract class TextContentHandler extends ContentHandler {
 727
 728         public function __construct( $modelName, $formats ) {
 729                 parent::__construct( $modelName, $formats );
 730         }
 731
 732         public function serializeContent( Content $content, $format = null ) {
 733                 $this->checkFormat( $format );
 734                 return $content->getNativeData();
 735         }
 736
 737         /**
 738          * attempts to merge differences between three versions.
 739          * Returns a new Content object for a clean merge and false for failure or a conflict.
 740          *
 741          * All three Content objects passed as parameters must have the same content model.
 742          *
 743          * This text-based implementation uses wfMerge().
 744          *
 745          * @param $oldContent String
 746          * @param $myContent String
 747          * @param $yourContent String
 748          * @return Content|Bool
 749          */
 750         public function merge3( Content $oldContent, Content $myContent, Content $yourContent ) {
 751                 $this->checkModelName( $oldContent->getModelName() );
 752                 $this->checkModelName( $myContent->getModelName() );
 753                 $this->checkModelName( $yourContent->getModelName() );
 754
 755                 $format = $this->getDefaultFormat();
 756
 757                 $old = $this->serializeContent( $oldContent, $format );
 758                 $mine = $this->serializeContent( $myContent, $format );
 759                 $yours = $this->serializeContent( $yourContent, $format );
 760
 761                 $ok = wfMerge( $old, $mine, $yours, $result );
 762
 763                 if ( !$ok ) {
 764                         return false;
 765                 }
 766
 767                 if ( !$result ) {
 768                         return $this->makeEmptyContent();
 769                 }
 770
 771                 $mergedContent = $this->unserializeContent( $result, $format );
 772                 return $mergedContent;
 773         }
 774
 775
 776 }
 777
 778 /**
 779  * @since WD.1
 780  */
 781 class WikitextContentHandler extends TextContentHandler {
 782
 783         public function __construct( $modelName = CONTENT_MODEL_WIKITEXT ) {
 784                 parent::__construct( $modelName, array( 'text/x-wiki' ) );
 785         }
 786
 787         public function unserializeContent( $text, $format = null ) {
 788                 $this->checkFormat( $format );
 789
 790                 return new WikitextContent( $text );
 791         }
 792
 793         public function makeEmptyContent() {
 794                 return new WikitextContent( '' );
 795         }
 796
 797
 798 }
 799
 800 #XXX: make ScriptContentHandler base class with plugin interface for syntax highlighting?
 801
 802 /**
 803  * @since WD.1
 804  */
 805 class JavaScriptContentHandler extends TextContentHandler {
 806
 807         public function __construct( $modelName = CONTENT_MODEL_WIKITEXT ) {
 808                 parent::__construct( $modelName, array( 'text/javascript' ) ); #XXX: or use $wgJsMimeType? this is for internal storage, not HTTP...
 809         }
 810
 811         public function unserializeContent( $text, $format = null ) {
 812                 $this->checkFormat( $format );
 813
 814                 return new JavaScriptContent( $text );
 815         }
 816
 817         public function makeEmptyContent() {
 818                 return new JavaScriptContent( '' );
 819         }
 820 }
 821
 822 /**
 823  * @since WD.1
 824  */
 825 class CssContentHandler extends TextContentHandler {
 826
 827         public function __construct( $modelName = CONTENT_MODEL_WIKITEXT ) {
 828                 parent::__construct( $modelName, array( 'text/css' ) );
 829         }
 830
 831         public function unserializeContent( $text, $format = null ) {
 832                 $this->checkFormat( $format );
 833
 834                 return new CssContent( $text );
 835         }
 836
 837         public function makeEmptyContent() {
 838                 return new CssContent( '' );
 839         }
 840
 841 }