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  * This program is free software; you can redistribute it and/or modify
  28  * it under the terms of the GNU General Public License as published by
  29  * the Free Software Foundation; either version 2 of the License, or
  30  * (at your option) any later version.
  31  *
  32  * This program is distributed in the hope that it will be useful,
  33  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  34  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  35  * GNU General Public License for more details.
  36  *
  37  * You should have received a copy of the GNU General Public License along
  38  * with this program; if not, write to the Free Software Foundation, Inc.,
  39  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  40  * http://www.gnu.org/copyleft/gpl.html
  41  *
  42  * @since 1.21
  43  *
  44  * @file
  45  * @ingroup Content
  46  *
  47  * @author Daniel Kinzler
  48  */
  49 abstract class ContentHandler {
  50
  51         /**
  52          * Switch for enabling deprecation warnings. Used by ContentHandler::deprecated()
  53          * and ContentHandler::runLegacyHooks().
  54          *
  55          * Once the ContentHandler code has settled in a bit, this should be set to true to
  56          * make extensions etc. show warnings when using deprecated functions and hooks.
  57          */
  58         protected static $enableDeprecationWarnings = false;
  59
  60         /**
  61          * Convenience function for getting flat text from a Content object. This
  62          * should only be used in the context of backwards compatibility with code
  63          * that is not yet able to handle Content objects!
  64          *
  65          * If $content is null, this method returns the empty string.
  66          *
  67          * If $content is an instance of TextContent, this method returns the flat
  68          * text as returned by $content->getNativeData().
  69          *
  70          * If $content is not a TextContent object, the behavior of this method
  71          * depends on the global $wgContentHandlerTextFallback:
  72          * - If $wgContentHandlerTextFallback is 'fail' and $content is not a
  73          *   TextContent object, an MWException is thrown.
  74          * - If $wgContentHandlerTextFallback is 'serialize' and $content is not a
  75          *   TextContent object, $content->serialize() is called to get a string
  76          *   form of the content.
  77          * - If $wgContentHandlerTextFallback is 'ignore' and $content is not a
  78          *   TextContent object, this method returns null.
  79          * - otherwise, the behaviour is undefined.
  80          *
  81          * @since 1.21
  82          *
  83          * @param $content Content|null
  84          * @return null|string the textual form of $content, if available
  85          * @throws MWException if $content is not an instance of TextContent and
  86          *   $wgContentHandlerTextFallback was set to 'fail'.
  87          */
  88         public static function getContentText( Content $content = null ) {
  89                 global $wgContentHandlerTextFallback;
  90
  91                 if ( is_null( $content ) ) {
  92                         return '';
  93                 }
  94
  95                 if ( $content instanceof TextContent ) {
  96                         return $content->getNativeData();
  97                 }
  98
  99                 wfDebugLog( 'ContentHandler', 'Accessing ' . $content->getModel() . ' content as text!' );
 100
 101                 if ( $wgContentHandlerTextFallback == 'fail' ) {
 102                         throw new MWException(
 103                                 "Attempt to get text from Content with model " .
 104                                 $content->getModel()
 105                         );
 106                 }
 107
 108                 if ( $wgContentHandlerTextFallback == 'serialize' ) {
 109                         return $content->serialize();
 110                 }
 111
 112                 return null;
 113         }
 114
 115         /**
 116          * Convenience function for creating a Content object from a given textual
 117          * representation.
 118          *
 119          * $text will be deserialized into a Content object of the model specified
 120          * by $modelId (or, if that is not given, $title->getContentModel()) using
 121          * the given format.
 122          *
 123          * @since 1.21
 124          *
 125          * @param $text string the textual representation, will be
 126          *    unserialized to create the Content object
 127          * @param $title null|Title the title of the page this text belongs to.
 128          *    Required if $modelId is not provided.
 129          * @param $modelId null|string the model to deserialize to. If not provided,
 130          *    $title->getContentModel() is used.
 131          * @param $format null|string the format to use for deserialization. If not
 132          *    given, the model's default format is used.
 133          *
 134          * @throws MWException
 135          * @return Content a Content object representing $text
 136          *
 137          * @throw MWException if $model or $format is not supported or if $text can
 138          *    not be unserialized using $format.
 139          */
 140         public static function makeContent( $text, Title $title = null,
 141                 $modelId = null, $format = null )
 142         {
 143                 if ( is_null( $modelId ) ) {
 144                         if ( is_null( $title ) ) {
 145                                 throw new MWException( "Must provide a Title object or a content model ID." );
 146                         }
 147
 148                         $modelId = $title->getContentModel();
 149                 }
 150
 151                 $handler = ContentHandler::getForModelID( $modelId );
 152                 return $handler->unserializeContent( $text, $format );
 153         }
 154
 155         /**
 156          * Returns the name of the default content model to be used for the page
 157          * with the given title.
 158          *
 159          * Note: There should rarely be need to call this method directly.
 160          * To determine the actual content model for a given page, use
 161          * Title::getContentModel().
 162          *
 163          * Which model is to be used by default for the page is determined based
 164          * on several factors:
 165          * - The global setting $wgNamespaceContentModels specifies a content model
 166          *   per namespace.
 167          * - The hook ContentHandlerDefaultModelFor may be used to override the page's default
 168          *   model.
 169          * - Pages in NS_MEDIAWIKI and NS_USER default to the CSS or JavaScript
 170          *   model if they end in .js or .css, respectively.
 171          * - Pages in NS_MEDIAWIKI default to the wikitext model otherwise.
 172          * - The hook TitleIsCssOrJsPage may be used to force a page to use the CSS
 173          *   or JavaScript model. This is a compatibility feature. The ContentHandlerDefaultModelFor
 174          *   hook should be used instead if possible.
 175          * - The hook TitleIsWikitextPage may be used to force a page to use the
 176          *   wikitext model. This is a compatibility feature. The ContentHandlerDefaultModelFor
 177          *   hook should be used instead if possible.
 178          *
 179          * If none of the above applies, the wikitext model is used.
 180          *
 181          * Note: this is used by, and may thus not use, Title::getContentModel()
 182          *
 183          * @since 1.21
 184          *
 185          * @param $title Title
 186          * @return null|string default model name for the page given by $title
 187          */
 188         public static function getDefaultModelFor( Title $title ) {
 189                 // NOTE: this method must not rely on $title->getContentModel() directly or indirectly,
 190                 //       because it is used to initialize the mContentModel member.
 191
 192                 $ns = $title->getNamespace();
 193
 194                 $ext = false;
 195                 $m = null;
 196                 $model = MWNamespace::getNamespaceContentModel( $ns );
 197
 198                 // Hook can determine default model
 199                 if ( !wfRunHooks( 'ContentHandlerDefaultModelFor', array( $title, &$model ) ) ) {
 200                         if ( !is_null( $model ) ) {
 201                                 return $model;
 202                         }
 203                 }
 204
 205                 // Could this page contain custom CSS or JavaScript, based on the title?
 206                 $isCssOrJsPage = NS_MEDIAWIKI == $ns && preg_match( '!\.(css|js)$!u', $title->getText(), $m );
 207                 if ( $isCssOrJsPage ) {
 208                         $ext = $m[1];
 209                 }
 210
 211                 // Hook can force JS/CSS
 212                 wfRunHooks( 'TitleIsCssOrJsPage', array( $title, &$isCssOrJsPage ) );
 213
 214                 // Is this a .css subpage of a user page?
 215                 $isJsCssSubpage = NS_USER == $ns
 216                         && !$isCssOrJsPage
 217                         && preg_match( "/\\/.*\\.(js|css)$/", $title->getText(), $m );
 218                 if ( $isJsCssSubpage ) {
 219                         $ext = $m[1];
 220                 }
 221
 222                 // Is this wikitext, according to $wgNamespaceContentModels or the DefaultModelFor hook?
 223                 $isWikitext = is_null( $model ) || $model == CONTENT_MODEL_WIKITEXT;
 224                 $isWikitext = $isWikitext && !$isCssOrJsPage && !$isJsCssSubpage;
 225
 226                 // Hook can override $isWikitext
 227                 wfRunHooks( 'TitleIsWikitextPage', array( $title, &$isWikitext ) );
 228
 229                 if ( !$isWikitext ) {
 230                         switch ( $ext ) {
 231                                 case 'js':
 232                                         return CONTENT_MODEL_JAVASCRIPT;
 233                                 case 'css':
 234                                         return CONTENT_MODEL_CSS;
 235                                 default:
 236                                         return is_null( $model ) ? CONTENT_MODEL_TEXT : $model;
 237                         }
 238                 }
 239
 240                 // We established that it must be wikitext
 241
 242                 return CONTENT_MODEL_WIKITEXT;
 243         }
 244
 245         /**
 246          * Returns the appropriate ContentHandler singleton for the given title.
 247          *
 248          * @since 1.21
 249          *
 250          * @param $title Title
 251          * @return ContentHandler
 252          */
 253         public static function getForTitle( Title $title ) {
 254                 $modelId = $title->getContentModel();
 255                 return ContentHandler::getForModelID( $modelId );
 256         }
 257
 258         /**
 259          * Returns the appropriate ContentHandler singleton for the given Content
 260          * object.
 261          *
 262          * @since 1.21
 263          *
 264          * @param $content Content
 265          * @return ContentHandler
 266          */
 267         public static function getForContent( Content $content ) {
 268                 $modelId = $content->getModel();
 269                 return ContentHandler::getForModelID( $modelId );
 270         }
 271
 272         /**
 273          * @var Array A Cache of ContentHandler instances by model id
 274          */
 275         static $handlers;
 276
 277         /**
 278          * Returns the ContentHandler singleton for the given model ID. Use the
 279          * CONTENT_MODEL_XXX constants to identify the desired content model.
 280          *
 281          * ContentHandler singletons are taken from the global $wgContentHandlers
 282          * array. Keys in that array are model names, the values are either
 283          * ContentHandler singleton objects, or strings specifying the appropriate
 284          * subclass of ContentHandler.
 285          *
 286          * If a class name is encountered when looking up the singleton for a given
 287          * model name, the class is instantiated and the class name is replaced by
 288          * the resulting singleton in $wgContentHandlers.
 289          *
 290          * If no ContentHandler is defined for the desired $modelId, the
 291          * ContentHandler may be provided by the ContentHandlerForModelID hook.
 292          * If no ContentHandler can be determined, an MWException is raised.
 293          *
 294          * @since 1.21
 295          *
 296          * @param $modelId String The ID of the content model for which to get a
 297          *    handler. Use CONTENT_MODEL_XXX constants.
 298          * @return ContentHandler The ContentHandler singleton for handling the
 299          *    model given by $modelId
 300          * @throws MWException if no handler is known for $modelId.
 301          */
 302         public static function getForModelID( $modelId ) {
 303                 global $wgContentHandlers;
 304
 305                 if ( isset( ContentHandler::$handlers[$modelId] ) ) {
 306                         return ContentHandler::$handlers[$modelId];
 307                 }
 308
 309                 if ( empty( $wgContentHandlers[$modelId] ) ) {
 310                         $handler = null;
 311
 312                         wfRunHooks( 'ContentHandlerForModelID', array( $modelId, &$handler ) );
 313
 314                         if ( $handler === null ) {
 315                                 throw new MWException( "No handler for model '$modelId'' registered in \$wgContentHandlers" );
 316                         }
 317
 318                         if ( !( $handler instanceof ContentHandler ) ) {
 319                                 throw new MWException( "ContentHandlerForModelID must supply a ContentHandler instance" );
 320                         }
 321                 } else {
 322                         $class = $wgContentHandlers[$modelId];
 323                         $handler = new $class( $modelId );
 324
 325                         if ( !( $handler instanceof ContentHandler ) ) {
 326                                 throw new MWException( "$class from \$wgContentHandlers is not compatible with ContentHandler" );
 327                         }
 328                 }
 329
 330                 wfDebugLog( 'ContentHandler', 'Created handler for ' . $modelId
 331                                         . ': ' . get_class( $handler ) );
 332
 333                 ContentHandler::$handlers[$modelId] = $handler;
 334                 return ContentHandler::$handlers[$modelId];
 335         }
 336
 337         /**
 338          * Returns the localized name for a given content model.
 339          *
 340          * Model names are localized using system messages. Message keys
 341          * have the form content-model-$name, where $name is getContentModelName( $id ).
 342          *
 343          * @param $name String The content model ID, as given by a CONTENT_MODEL_XXX
 344          *    constant or returned by Revision::getContentModel().
 345          *
 346          * @return string The content format's localized name.
 347          * @throws MWException if the model id isn't known.
 348          */
 349         public static function getLocalizedName( $name ) {
 350                 $key = "content-model-$name";
 351
 352                 $msg = wfMessage( $key );
 353
 354                 return $msg->exists() ? $msg->plain() : $name;
 355         }
 356
 357         public static function getContentModels() {
 358                 global $wgContentHandlers;
 359
 360                 return array_keys( $wgContentHandlers );
 361         }
 362
 363         public static function getAllContentFormats() {
 364                 global $wgContentHandlers;
 365
 366                 $formats = array();
 367
 368                 foreach ( $wgContentHandlers as $model => $class ) {
 369                         $handler = ContentHandler::getForModelID( $model );
 370                         $formats = array_merge( $formats, $handler->getSupportedFormats() );
 371                 }
 372
 373                 $formats = array_unique( $formats );
 374                 return $formats;
 375         }
 376
 377         // ------------------------------------------------------------------------
 378
 379         protected $mModelID;
 380         protected $mSupportedFormats;
 381
 382         /**
 383          * Constructor, initializing the ContentHandler instance with its model ID
 384          * and a list of supported formats. Values for the parameters are typically
 385          * provided as literals by subclass's constructors.
 386          *
 387          * @param $modelId String (use CONTENT_MODEL_XXX constants).
 388          * @param $formats array List for supported serialization formats
 389          *    (typically as MIME types)
 390          */
 391         public function __construct( $modelId, $formats ) {
 392                 $this->mModelID = $modelId;
 393                 $this->mSupportedFormats = $formats;
 394
 395                 $this->mModelName = preg_replace( '/(Content)?Handler$/', '', get_class( $this ) );
 396                 $this->mModelName = preg_replace( '/[_\\\\]/', '', $this->mModelName );
 397                 $this->mModelName = strtolower( $this->mModelName );
 398         }
 399
 400         /**
 401          * Serializes a Content object of the type supported by this ContentHandler.
 402          *
 403          * @since 1.21
 404          *
 405          * @param $content Content The Content object to serialize
 406          * @param $format null|String The desired serialization format
 407          * @return string Serialized form of the content
 408          */
 409         public abstract function serializeContent( Content $content, $format = null );
 410
 411         /**
 412          * Unserializes a Content object of the type supported by this ContentHandler.
 413          *
 414          * @since 1.21
 415          *
 416          * @param $blob string serialized form of the content
 417          * @param $format null|String the format used for serialization
 418          * @return Content the Content object created by deserializing $blob
 419          */
 420         public abstract function unserializeContent( $blob, $format = null );
 421
 422         /**
 423          * Creates an empty Content object of the type supported by this
 424          * ContentHandler.
 425          *
 426          * @since 1.21
 427          *
 428          * @return Content
 429          */
 430         public abstract function makeEmptyContent();
 431
 432         /**
 433          * Creates a new Content object that acts as a redirect to the given page,
 434          * or null of redirects are not supported by this content model.
 435          *
 436          * This default implementation always returns null. Subclasses supporting redirects
 437          * must override this method.
 438          *
 439          * @since 1.21
 440          *
 441          * @param Title $destination the page to redirect to.
 442          *
 443          * @return Content
 444          */
 445         public function makeRedirectContent( Title $destination ) {
 446                 return null;
 447         }
 448
 449         /**
 450          * Returns the model id that identifies the content model this
 451          * ContentHandler can handle. Use with the CONTENT_MODEL_XXX constants.
 452          *
 453          * @since 1.21
 454          *
 455          * @return String The model ID
 456          */
 457         public function getModelID() {
 458                 return $this->mModelID;
 459         }
 460
 461         /**
 462          * Throws an MWException if $model_id is not the ID of the content model
 463          * supported by this ContentHandler.
 464          *
 465          * @since 1.21
 466          *
 467          * @param String $model_id The model to check
 468          *
 469          * @throws MWException
 470          */
 471         protected function checkModelID( $model_id ) {
 472                 if ( $model_id !== $this->mModelID ) {
 473                         throw new MWException( "Bad content model: " .
 474                                 "expected {$this->mModelID} " .
 475                                 "but got $model_id." );
 476                 }
 477         }
 478
 479         /**
 480          * Returns a list of serialization formats supported by the
 481          * serializeContent() and unserializeContent() methods of this
 482          * ContentHandler.
 483          *
 484          * @since 1.21
 485          *
 486          * @return array of serialization formats as MIME type like strings
 487          */
 488         public function getSupportedFormats() {
 489                 return $this->mSupportedFormats;
 490         }
 491
 492         /**
 493          * The format used for serialization/deserialization by default by this
 494          * ContentHandler.
 495          *
 496          * This default implementation will return the first element of the array
 497          * of formats that was passed to the constructor.
 498          *
 499          * @since 1.21
 500          *
 501          * @return string the name of the default serialization format as a MIME type
 502          */
 503         public function getDefaultFormat() {
 504                 return $this->mSupportedFormats[0];
 505         }
 506
 507         /**
 508          * Returns true if $format is a serialization format supported by this
 509          * ContentHandler, and false otherwise.
 510          *
 511          * Note that if $format is null, this method always returns true, because
 512          * null means "use the default format".
 513          *
 514          * @since 1.21
 515          *
 516          * @param $format string the serialization format to check
 517          * @return bool
 518          */
 519         public function isSupportedFormat( $format ) {
 520
 521                 if ( !$format ) {
 522                         return true; // this means "use the default"
 523                 }
 524
 525                 return in_array( $format, $this->mSupportedFormats );
 526         }
 527
 528         /**
 529          * Throws an MWException if isSupportedFormat( $format ) is not true.
 530          * Convenient for checking whether a format provided as a parameter is
 531          * actually supported.
 532          *
 533          * @param $format string the serialization format to check
 534          *
 535          * @throws MWException
 536          */
 537         protected function checkFormat( $format ) {
 538                 if ( !$this->isSupportedFormat( $format ) ) {
 539                         throw new MWException(
 540                                 "Format $format is not supported for content model "
 541                                 . $this->getModelID()
 542                         );
 543                 }
 544         }
 545
 546         /**
 547          * Returns overrides for action handlers.
 548          * Classes listed here will be used instead of the default one when
 549          * (and only when) $wgActions[$action] === true. This allows subclasses
 550          * to override the default action handlers.
 551          *
 552          * @since 1.21
 553          *
 554          * @return Array
 555          */
 556         public function getActionOverrides() {
 557                 return array();
 558         }
 559
 560         /**
 561          * Factory for creating an appropriate DifferenceEngine for this content model.
 562          *
 563          * @since 1.21
 564          *
 565          * @param $context IContextSource context to use, anything else will be
 566          *    ignored
 567          * @param $old Integer Old ID we want to show and diff with.
 568          * @param $new int|string String either 'prev' or 'next'.
 569          * @param $rcid Integer ??? FIXME (default 0)
 570          * @param $refreshCache boolean If set, refreshes the diff cache
 571          * @param $unhide boolean If set, allow viewing deleted revs
 572          *
 573          * @return DifferenceEngine
 574          */
 575         public function createDifferenceEngine( IContextSource $context,
 576                 $old = 0, $new = 0,
 577                 $rcid = 0, # FIXME: use everywhere!
 578                 $refreshCache = false, $unhide = false
 579         ) {
 580                 $diffEngineClass = $this->getDiffEngineClass();
 581
 582                 return new $diffEngineClass( $context, $old, $new, $rcid, $refreshCache, $unhide );
 583         }
 584
 585         /**
 586          * Get the language in which the content of the given page is written.
 587          *
 588          * This default implementation just returns $wgContLang (except for pages in the MediaWiki namespace)
 589          *
 590          * Note that the pages language is not cacheable, since it may in some cases depend on user settings.
 591          *
 592          * Also note that the page language may or may not depend on the actual content of the page,
 593          * that is, this method may load the content in order to determine the language.
 594          *
 595          * @since 1.21
 596          *
 597          * @param Title        $title the page to determine the language for.
 598          * @param Content|null $content the page's content, if you have it handy, to avoid reloading it.
 599          *
 600          * @return Language the page's language
 601          */
 602         public function getPageLanguage( Title $title, Content $content = null ) {
 603                 global $wgContLang, $wgLang;
 604                 $pageLang = $wgContLang;
 605
 606                 if ( $title->getNamespace() == NS_MEDIAWIKI ) {
 607                         // Parse mediawiki messages with correct target language
 608                         list( /* $unused */, $lang ) = MessageCache::singleton()->figureMessage( $title->getText() );
 609                         $pageLang = wfGetLangObj( $lang );
 610                 }
 611
 612                 wfRunHooks( 'PageContentLanguage', array( $title, &$pageLang, $wgLang ) );
 613                 return wfGetLangObj( $pageLang );
 614         }
 615
 616         /**
 617          * Get the language in which the content of this page is written when
 618          * viewed by user. Defaults to $this->getPageLanguage(), but if the user
 619          * specified a preferred variant, the variant will be used.
 620          *
 621          * This default implementation just returns $this->getPageLanguage( $title, $content ) unless
 622          * the user specified a preferred variant.
 623          *
 624          * Note that the pages view language is not cacheable, since it depends on user settings.
 625          *
 626          * Also note that the page language may or may not depend on the actual content of the page,
 627          * that is, this method may load the content in order to determine the language.
 628          *
 629          * @since 1.21
 630          *
 631          * @param Title        $title the page to determine the language for.
 632          * @param Content|null $content the page's content, if you have it handy, to avoid reloading it.
 633          *
 634          * @return Language the page's language for viewing
 635          */
 636         public function getPageViewLanguage( Title $title, Content $content = null ) {
 637                 $pageLang = $this->getPageLanguage( $title, $content );
 638
 639                 if ( $title->getNamespace() !== NS_MEDIAWIKI ) {
 640                         // If the user chooses a variant, the content is actually
 641                         // in a language whose code is the variant code.
 642                         $variant = $pageLang->getPreferredVariant();
 643                         if ( $pageLang->getCode() !== $variant ) {
 644                                 $pageLang = Language::factory( $variant );
 645                         }
 646                 }
 647
 648                 return $pageLang;
 649         }
 650
 651         /**
 652          * Determines whether the content type handled by this ContentHandler
 653          * can be used on the given page.
 654          *
 655          * This default implementation always returns true.
 656          * Subclasses may override this to restrict the use of this content model to specific locations,
 657          * typically based on the namespace or some other aspect of the title, such as a special suffix
 658          * (e.g. ".svg" for SVG content).
 659          *
 660          * @param Title $title the page's title.
 661          *
 662          * @return bool true if content of this kind can be used on the given page, false otherwise.
 663          */
 664         public function canBeUsedOn( Title $title ) {
 665                 return true;
 666         }
 667
 668         /**
 669          * Returns the name of the diff engine to use.
 670          *
 671          * @since 1.21
 672          *
 673          * @return string
 674          */
 675         protected function getDiffEngineClass() {
 676                 return 'DifferenceEngine';
 677         }
 678
 679         /**
 680          * Attempts to merge differences between three versions.
 681          * Returns a new Content object for a clean merge and false for failure or
 682          * a conflict.
 683          *
 684          * This default implementation always returns false.
 685          *
 686          * @since 1.21
 687          *
 688          * @param $oldContent Content|string  String
 689          * @param $myContent Content|string   String
 690          * @param $yourContent Content|string String
 691          *
 692          * @return Content|Bool
 693          */
 694         public function merge3( Content $oldContent, Content $myContent, Content $yourContent ) {
 695                 return false;
 696         }
 697
 698         /**
 699          * Return an applicable auto-summary if one exists for the given edit.
 700          *
 701          * @since 1.21
 702          *
 703          * @param $oldContent Content|null: the previous text of the page.
 704          * @param $newContent Content|null: The submitted text of the page.
 705          * @param $flags int Bit mask: a bit mask of flags submitted for the edit.
 706          *
 707          * @return string An appropriate auto-summary, or an empty string.
 708          */
 709         public function getAutosummary( Content $oldContent = null, Content $newContent = null, $flags ) {
 710                 // Decide what kind of auto-summary is needed.
 711
 712                 // Redirect auto-summaries
 713
 714                 /**
 715                  * @var $ot Title
 716                  * @var $rt Title
 717                  */
 718
 719                 $ot = !is_null( $oldContent ) ? $oldContent->getRedirectTarget() : null;
 720                 $rt = !is_null( $newContent ) ? $newContent->getRedirectTarget() : null;
 721
 722                 if ( is_object( $rt ) ) {
 723                         if ( !is_object( $ot )
 724                                 || !$rt->equals( $ot )
 725                                 || $ot->getFragment() != $rt->getFragment() )
 726                         {
 727                                 $truncatedtext = $newContent->getTextForSummary(
 728                                         250
 729                                                 - strlen( wfMessage( 'autoredircomment' )->inContentLanguage()->text() )
 730                                                 - strlen( $rt->getFullText() ) );
 731
 732                                 return wfMessage( 'autoredircomment', $rt->getFullText() )
 733                                                 ->rawParams( $truncatedtext )->inContentLanguage()->text();
 734                         }
 735                 }
 736
 737                 // New page auto-summaries
 738                 if ( $flags & EDIT_NEW && $newContent->getSize() > 0 ) {
 739                         // If they're making a new article, give its text, truncated, in
 740                         // the summary.
 741
 742                         $truncatedtext = $newContent->getTextForSummary(
 743                                 200 - strlen( wfMessage( 'autosumm-new' )->inContentLanguage()->text() ) );
 744
 745                         return wfMessage( 'autosumm-new' )->rawParams( $truncatedtext )
 746                                         ->inContentLanguage()->text();
 747                 }
 748
 749                 // Blanking auto-summaries
 750                 if ( !empty( $oldContent ) && $oldContent->getSize() > 0 && $newContent->getSize() == 0 ) {
 751                         return wfMessage( 'autosumm-blank' )->inContentLanguage()->text();
 752                 } elseif ( !empty( $oldContent )
 753                         && $oldContent->getSize() > 10 * $newContent->getSize()
 754                         && $newContent->getSize() < 500 )
 755                 {
 756                         // Removing more than 90% of the article
 757
 758                         $truncatedtext = $newContent->getTextForSummary(
 759                                 200 - strlen( wfMessage( 'autosumm-replace' )->inContentLanguage()->text() ) );
 760
 761                         return wfMessage( 'autosumm-replace' )->rawParams( $truncatedtext )
 762                                         ->inContentLanguage()->text();
 763                 }
 764
 765                 // If we reach this point, there's no applicable auto-summary for our
 766                 // case, so our auto-summary is empty.
 767                 return '';
 768         }
 769
 770         /**
 771          * Auto-generates a deletion reason
 772          *
 773          * @since 1.21
 774          *
 775          * @param $title Title: the page's title
 776          * @param &$hasHistory Boolean: whether the page has a history
 777          * @return mixed String containing deletion reason or empty string, or
 778          *    boolean false if no revision occurred
 779          *
 780          * @XXX &$hasHistory is extremely ugly, it's here because
 781          * WikiPage::getAutoDeleteReason() and Article::getReason()
 782          * have it / want it.
 783          */
 784         public function getAutoDeleteReason( Title $title, &$hasHistory ) {
 785                 $dbw = wfGetDB( DB_MASTER );
 786
 787                 // Get the last revision
 788                 $rev = Revision::newFromTitle( $title );
 789
 790                 if ( is_null( $rev ) ) {
 791                         return false;
 792                 }
 793
 794                 // Get the article's contents
 795                 $content = $rev->getContent();
 796                 $blank = false;
 797
 798                 // If the page is blank, use the text from the previous revision,
 799                 // which can only be blank if there's a move/import/protect dummy
 800                 // revision involved
 801                 if ( !$content || $content->isEmpty() ) {
 802                         $prev = $rev->getPrevious();
 803
 804                         if ( $prev ) {
 805                                 $rev = $prev;
 806                                 $content = $rev->getContent();
 807                                 $blank = true;
 808                         }
 809                 }
 810
 811                 $this->checkModelID( $rev->getContentModel() );
 812
 813                 // Find out if there was only one contributor
 814                 // Only scan the last 20 revisions
 815                 $res = $dbw->select( 'revision', 'rev_user_text',
 816                         array(
 817                                 'rev_page' => $title->getArticleID(),
 818                                 $dbw->bitAnd( 'rev_deleted', Revision::DELETED_USER ) . ' = 0'
 819                         ),
 820                         __METHOD__,
 821                         array( 'LIMIT' => 20 )
 822                 );
 823
 824                 if ( $res === false ) {
 825                         // This page has no revisions, which is very weird
 826                         return false;
 827                 }
 828
 829                 $hasHistory = ( $res->numRows() > 1 );
 830                 $row = $dbw->fetchObject( $res );
 831
 832                 if ( $row ) { // $row is false if the only contributor is hidden
 833                         $onlyAuthor = $row->rev_user_text;
 834                         // Try to find a second contributor
 835                         foreach ( $res as $row ) {
 836                                 if ( $row->rev_user_text != $onlyAuthor ) { // Bug 22999
 837                                         $onlyAuthor = false;
 838                                         break;
 839                                 }
 840                         }
 841                 } else {
 842                         $onlyAuthor = false;
 843                 }
 844
 845                 // Generate the summary with a '$1' placeholder
 846                 if ( $blank ) {
 847                         // The current revision is blank and the one before is also
 848                         // blank. It's just not our lucky day
 849                         $reason = wfMessage( 'exbeforeblank', '$1' )->inContentLanguage()->text();
 850                 } else {
 851                         if ( $onlyAuthor ) {
 852                                 $reason = wfMessage(
 853                                         'excontentauthor',
 854                                         '$1',
 855                                         $onlyAuthor
 856                                 )->inContentLanguage()->text();
 857                         } else {
 858                                 $reason = wfMessage( 'excontent', '$1' )->inContentLanguage()->text();
 859                         }
 860                 }
 861
 862                 if ( $reason == '-' ) {
 863                         // Allow these UI messages to be blanked out cleanly
 864                         return '';
 865                 }
 866
 867                 // Max content length = max comment length - length of the comment (excl. $1)
 868                 $text = $content ? $content->getTextForSummary( 255 - ( strlen( $reason ) - 2 ) ) : '';
 869
 870                 // Now replace the '$1' placeholder
 871                 $reason = str_replace( '$1', $text, $reason );
 872
 873                 return $reason;
 874         }
 875
 876         /**
 877          * Get the Content object that needs to be saved in order to undo all revisions
 878          * between $undo and $undoafter. Revisions must belong to the same page,
 879          * must exist and must not be deleted.
 880          *
 881          * @since 1.21
 882          *
 883          * @param $current Revision The current text
 884          * @param $undo Revision The revision to undo
 885          * @param $undoafter Revision Must be an earlier revision than $undo
 886          *
 887          * @return mixed String on success, false on failure
 888          */
 889         public function getUndoContent( Revision $current, Revision $undo, Revision $undoafter ) {
 890                 $cur_content = $current->getContent();
 891
 892                 if ( empty( $cur_content ) ) {
 893                         return false; // no page
 894                 }
 895
 896                 $undo_content = $undo->getContent();
 897                 $undoafter_content = $undoafter->getContent();
 898
 899                 $this->checkModelID( $cur_content->getModel() );
 900                 $this->checkModelID( $undo_content->getModel() );
 901                 $this->checkModelID( $undoafter_content->getModel() );
 902
 903                 if ( $cur_content->equals( $undo_content ) ) {
 904                         // No use doing a merge if it's just a straight revert.
 905                         return $undoafter_content;
 906                 }
 907
 908                 $undone_content = $this->merge3( $undo_content, $undoafter_content, $cur_content );
 909
 910                 return $undone_content;
 911         }
 912
 913         /**
 914          * Get parser options suitable for rendering the primary article wikitext
 915          *
 916          * @param IContextSource|User|string $context One of the following:
 917          *        - IContextSource: Use the User and the Language of the provided
 918          *                                            context
 919          *        - User: Use the provided User object and $wgLang for the language,
 920          *                                            so use an IContextSource object if possible.
 921          *        - 'canonical': Canonical options (anonymous user with default
 922          *                                            preferences and content language).
 923          *
 924          * @param IContextSource|User|string $context
 925          *
 926          * @throws MWException
 927          * @return ParserOptions
 928          */
 929         public function makeParserOptions( $context ) {
 930                 global $wgContLang;
 931
 932                 if ( $context instanceof IContextSource ) {
 933                         $options = ParserOptions::newFromContext( $context );
 934                 } elseif ( $context instanceof User ) { // settings per user (even anons)
 935                         $options = ParserOptions::newFromUser( $context );
 936                 } elseif ( $context === 'canonical' ) { // canonical settings
 937                         $options = ParserOptions::newFromUserAndLang( new User, $wgContLang );
 938                 } else {
 939                         throw new MWException( "Bad context for parser options: $context" );
 940                 }
 941
 942                 $options->enableLimitReport(); // show inclusion/loop reports
 943                 $options->setTidy( true ); // fix bad HTML
 944
 945                 return $options;
 946         }
 947
 948         /**
 949          * Returns true for content models that support caching using the
 950          * ParserCache mechanism. See WikiPage::isParserCacheUsed().
 951          *
 952          * @since 1.21
 953          *
 954          * @return bool
 955          */
 956         public function isParserCacheSupported() {
 957                 return false;
 958         }
 959
 960         /**
 961          * Returns true if this content model supports sections.
 962          *
 963          * This default implementation returns false.
 964          *
 965          * @return boolean whether sections are supported.
 966          */
 967         public function supportsSections() {
 968                 return false;
 969         }
 970
 971         /**
 972          * Logs a deprecation warning, visible if $wgDevelopmentWarnings, but only if
 973          * self::$enableDeprecationWarnings is set to true.
 974          *
 975          * @param String      $func The name of the deprecated function
 976          * @param string      $version The version since the method is deprecated. Usually 1.21
 977          *                    for ContentHandler related stuff.
 978          * @param String|bool $component: Component to which the function belongs.
 979          *                                If false, it is assumed the function is in MediaWiki core.
 980          *
 981          * @see ContentHandler::$enableDeprecationWarnings
 982          * @see wfDeprecated
 983          */
 984         public static function deprecated( $func, $version, $component = false ) {
 985                 if ( self::$enableDeprecationWarnings ) {
 986                         wfDeprecated( $func, $version, $component, 3 );
 987                 }
 988         }
 989
 990         /**
 991          * Call a legacy hook that uses text instead of Content objects.
 992          * Will log a warning when a matching hook function is registered.
 993          * If the textual representation of the content is changed by the
 994          * hook function, a new Content object is constructed from the new
 995          * text.
 996          *
 997          * @param $event String: event name
 998          * @param $args Array: parameters passed to hook functions
 999          * @param $warn bool: whether to log a warning.
1000          *                    Default to self::$enableDeprecationWarnings.
1001          *                    May be set to false for testing.
1002          *
1003          * @return Boolean True if no handler aborted the hook
1004          *
1005          * @see ContentHandler::$enableDeprecationWarnings
1006          */
1007         public static function runLegacyHooks( $event, $args = array(),
1008                         $warn = null ) {
1009
1010                 if ( $warn === null ) {
1011                         $warn = self::$enableDeprecationWarnings;
1012                 }
1013
1014                 if ( !Hooks::isRegistered( $event ) ) {
1015                         return true; // nothing to do here
1016                 }
1017
1018                 if ( $warn ) {
1019                         // Log information about which handlers are registered for the legacy hook,
1020                         // so we can find and fix them.
1021
1022                         $handlers = Hooks::getHandlers( $event );
1023                         $handlerInfo = array();
1024
1025                         wfSuppressWarnings();
1026
1027                         foreach ( $handlers as $handler ) {
1028                                 $info = '';
1029
1030                                 if ( is_array( $handler ) ) {
1031                                         if ( is_object( $handler[0] ) ) {
1032                                                 $info = get_class( $handler[0] );
1033                                         } else {
1034                                                 $info = $handler[0];
1035                                         }
1036
1037                                         if ( isset( $handler[1] ) ) {
1038                                                 $info .= '::' . $handler[1];
1039                                         }
1040                                 } else if ( is_object( $handler ) ) {
1041                                         $info = get_class( $handler[0] );
1042                                         $info .= '::on' . $event;
1043                                 } else {
1044                                         $info = $handler;
1045                                 }
1046
1047                                 $handlerInfo[] = $info;
1048                         }
1049
1050                         wfRestoreWarnings();
1051
1052                         wfWarn( "Using obsolete hook $event via ContentHandler::runLegacyHooks()! Handlers: " . implode(', ', $handlerInfo), 2 );
1053                 }
1054
1055                 // convert Content objects to text
1056                 $contentObjects = array();
1057                 $contentTexts = array();
1058
1059                 foreach ( $args as $k => $v ) {
1060                         if ( $v instanceof Content ) {
1061                                 /* @var Content $v */
1062
1063                                 $contentObjects[$k] = $v;
1064
1065                                 $v = $v->serialize();
1066                                 $contentTexts[ $k ] = $v;
1067                                 $args[ $k ] = $v;
1068                         }
1069                 }
1070
1071                 // call the hook functions
1072                 $ok = wfRunHooks( $event, $args );
1073
1074                 // see if the hook changed the text
1075                 foreach ( $contentTexts as $k => $orig ) {
1076                         /* @var Content $content */
1077
1078                         $modified = $args[ $k ];
1079                         $content = $contentObjects[$k];
1080
1081                         if ( $modified !== $orig ) {
1082                                 // text was changed, create updated Content object
1083                                 $content = $content->getContentHandler()->unserializeContent( $modified );
1084                         }
1085
1086                         $args[ $k ] = $content;
1087                 }
1088
1089                 return $ok;
1090         }
1091 }
1092