includes/content/AbstractContent.php

   1 <?php
   2 /**
   3  * A content object represents page content, e.g. the text to show on a page.
   4  * Content objects have no knowledge about how they relate to Wiki pages.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License along
  17  * with this program; if not, write to the Free Software Foundation, Inc.,
  18  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  19  * http://www.gnu.org/copyleft/gpl.html
  20  *
  21  * @since 1.21
  22  *
  23  * @file
  24  * @ingroup Content
  25  *
  26  * @author Daniel Kinzler
  27  */
  28
  29 /**
  30  * Base implementation for content objects.
  31  *
  32  * @ingroup Content
  33  */
  34 abstract class AbstractContent implements Content {
  35
  36         /**
  37          * Name of the content model this Content object represents.
  38          * Use with CONTENT_MODEL_XXX constants
  39          *
  40          * @since 1.21
  41          *
  42          * @var string $model_id
  43          */
  44         protected $model_id;
  45
  46         /**
  47          * @param string|null $modelId
  48          *
  49          * @since 1.21
  50          */
  51         public function __construct( $modelId = null ) {
  52                 $this->model_id = $modelId;
  53         }
  54
  55         /**
  56          * @see Content::getModel
  57          *
  58          * @since 1.21
  59          */
  60         public function getModel() {
  61                 return $this->model_id;
  62         }
  63
  64         /**
  65          * Throws an MWException if $model_id is not the id of the content model
  66          * supported by this Content object.
  67          *
  68          * @since 1.21
  69          *
  70          * @param string $modelId The model to check
  71          *
  72          * @throws MWException
  73          */
  74         protected function checkModelID( $modelId ) {
  75                 if ( $modelId !== $this->model_id ) {
  76                         throw new MWException(
  77                                 "Bad content model: " .
  78                                 "expected {$this->model_id} " .
  79                                 "but got $modelId."
  80                         );
  81                 }
  82         }
  83
  84         /**
  85          * @see Content::getContentHandler
  86          *
  87          * @since 1.21
  88          */
  89         public function getContentHandler() {
  90                 return ContentHandler::getForContent( $this );
  91         }
  92
  93         /**
  94          * @see Content::getDefaultFormat
  95          *
  96          * @since 1.21
  97          */
  98         public function getDefaultFormat() {
  99                 return $this->getContentHandler()->getDefaultFormat();
 100         }
 101
 102         /**
 103          * @see Content::getSupportedFormats
 104          *
 105          * @since 1.21
 106          */
 107         public function getSupportedFormats() {
 108                 return $this->getContentHandler()->getSupportedFormats();
 109         }
 110
 111         /**
 112          * @see Content::isSupportedFormat
 113          *
 114          * @param string $format
 115          *
 116          * @since 1.21
 117          *
 118          * @return boolean
 119          */
 120         public function isSupportedFormat( $format ) {
 121                 if ( !$format ) {
 122                         return true; // this means "use the default"
 123                 }
 124
 125                 return $this->getContentHandler()->isSupportedFormat( $format );
 126         }
 127
 128         /**
 129          * Throws an MWException if $this->isSupportedFormat( $format ) does not
 130          * return true.
 131          *
 132          * @since 1.21
 133          *
 134          * @param string $format
 135          * @throws MWException
 136          */
 137         protected function checkFormat( $format ) {
 138                 if ( !$this->isSupportedFormat( $format ) ) {
 139                         throw new MWException(
 140                                 "Format $format is not supported for content model " .
 141                                 $this->getModel()
 142                         );
 143                 }
 144         }
 145
 146         /**
 147          * @see Content::serialize
 148          *
 149          * @param string|null $format
 150          *
 151          * @since 1.21
 152          *
 153          * @return string
 154          */
 155         public function serialize( $format = null ) {
 156                 return $this->getContentHandler()->serializeContent( $this, $format );
 157         }
 158
 159         /**
 160          * @see Content::isEmpty
 161          *
 162          * @since 1.21
 163          *
 164          * @return boolean
 165          */
 166         public function isEmpty() {
 167                 return $this->getSize() === 0;
 168         }
 169
 170         /**
 171          * @see Content::isValid
 172          *
 173          * @since 1.21
 174          *
 175          * @return boolean
 176          */
 177         public function isValid() {
 178                 return true;
 179         }
 180
 181         /**
 182          * @see Content::equals
 183          *
 184          * @since 1.21
 185          *
 186          * @param Content|null $that
 187          *
 188          * @return boolean
 189          */
 190         public function equals( Content $that = null ) {
 191                 if ( is_null( $that ) ) {
 192                         return false;
 193                 }
 194
 195                 if ( $that === $this ) {
 196                         return true;
 197                 }
 198
 199                 if ( $that->getModel() !== $this->getModel() ) {
 200                         return false;
 201                 }
 202
 203                 return $this->getNativeData() === $that->getNativeData();
 204         }
 205
 206         /**
 207          * Returns a list of DataUpdate objects for recording information about this
 208          * Content in some secondary data store.
 209          *
 210          * This default implementation calls
 211          * $this->getParserOutput( $content, $title, null, null, false ),
 212          * and then calls getSecondaryDataUpdates( $title, $recursive ) on the
 213          * resulting ParserOutput object.
 214          *
 215          * Subclasses may override this to determine the secondary data updates more
 216          * efficiently, preferably without the need to generate a parser output object.
 217          *
 218          * @see Content::getSecondaryDataUpdates()
 219          *
 220          * @param $title Title The context for determining the necessary updates
 221          * @param $old Content|null An optional Content object representing the
 222          *    previous content, i.e. the content being replaced by this Content
 223          *    object.
 224          * @param $recursive boolean Whether to include recursive updates (default:
 225          *    false).
 226          * @param $parserOutput ParserOutput|null Optional ParserOutput object.
 227          *    Provide if you have one handy, to avoid re-parsing of the content.
 228          *
 229          * @return Array. A list of DataUpdate objects for putting information
 230          *    about this content object somewhere.
 231          *
 232          * @since 1.21
 233          */
 234         public function getSecondaryDataUpdates( Title $title,
 235                 Content $old = null,
 236                 $recursive = true, ParserOutput $parserOutput = null
 237         ) {
 238                 if ( $parserOutput === null ) {
 239                         $parserOutput = $this->getParserOutput( $title, null, null, false );
 240                 }
 241
 242                 return $parserOutput->getSecondaryDataUpdates( $title, $recursive );
 243         }
 244
 245         /**
 246          * @see Content::getRedirectChain
 247          *
 248          * @since 1.21
 249          */
 250         public function getRedirectChain() {
 251                 global $wgMaxRedirects;
 252                 $title = $this->getRedirectTarget();
 253                 if ( is_null( $title ) ) {
 254                         return null;
 255                 }
 256                 // recursive check to follow double redirects
 257                 $recurse = $wgMaxRedirects;
 258                 $titles = array( $title );
 259                 while ( --$recurse > 0 ) {
 260                         if ( $title->isRedirect() ) {
 261                                 $page = WikiPage::factory( $title );
 262                                 $newtitle = $page->getRedirectTarget();
 263                         } else {
 264                                 break;
 265                         }
 266                         // Redirects to some special pages are not permitted
 267                         if ( $newtitle instanceOf Title && $newtitle->isValidRedirectTarget() ) {
 268                                 // The new title passes the checks, so make that our current
 269                                 // title so that further recursion can be checked
 270                                 $title = $newtitle;
 271                                 $titles[] = $newtitle;
 272                         } else {
 273                                 break;
 274                         }
 275                 }
 276                 return $titles;
 277         }
 278
 279         /**
 280          * @see Content::getRedirectTarget
 281          *
 282          * @since 1.21
 283          */
 284         public function getRedirectTarget() {
 285                 return null;
 286         }
 287
 288         /**
 289          * @see Content::getUltimateRedirectTarget
 290          * @note: migrated here from Title::newFromRedirectRecurse
 291          *
 292          * @since 1.21
 293          */
 294         public function getUltimateRedirectTarget() {
 295                 $titles = $this->getRedirectChain();
 296                 return $titles ? array_pop( $titles ) : null;
 297         }
 298
 299         /**
 300          * @see Content::isRedirect
 301          *
 302          * @since 1.21
 303          *
 304          * @return bool
 305          */
 306         public function isRedirect() {
 307                 return $this->getRedirectTarget() !== null;
 308         }
 309
 310         /**
 311          * @see Content::updateRedirect
 312          *
 313          * This default implementation always returns $this.
 314          *
 315          * @param Title $target
 316          *
 317          * @since 1.21
 318          *
 319          * @return Content $this
 320          */
 321         public function updateRedirect( Title $target ) {
 322                 return $this;
 323         }
 324
 325         /**
 326          * @see Content::getSection
 327          *
 328          * @since 1.21
 329          */
 330         public function getSection( $sectionId ) {
 331                 return null;
 332         }
 333
 334         /**
 335          * @see Content::replaceSection
 336          *
 337          * @since 1.21
 338          */
 339         public function replaceSection( $section, Content $with, $sectionTitle = '' ) {
 340                 return null;
 341         }
 342
 343         /**
 344          * @see Content::preSaveTransform
 345          *
 346          * @since 1.21
 347          */
 348         public function preSaveTransform( Title $title, User $user, ParserOptions $popts ) {
 349                 return $this;
 350         }
 351
 352         /**
 353          * @see Content::addSectionHeader
 354          *
 355          * @since 1.21
 356          */
 357         public function addSectionHeader( $header ) {
 358                 return $this;
 359         }
 360
 361         /**
 362          * @see Content::preloadTransform
 363          *
 364          * @since 1.21
 365          */
 366         public function preloadTransform( Title $title, ParserOptions $popts ) {
 367                 return $this;
 368         }
 369
 370         /**
 371          * @see Content::prepareSave
 372          *
 373          * @since 1.21
 374          */
 375         public function prepareSave( WikiPage $page, $flags, $baseRevId, User $user ) {
 376                 if ( $this->isValid() ) {
 377                         return Status::newGood();
 378                 } else {
 379                         return Status::newFatal( "invalid-content-data" );
 380                 }
 381         }
 382
 383         /**
 384          * @see Content::getDeletionUpdates
 385          *
 386          * @since 1.21
 387          *
 388          * @param $page WikiPage the deleted page
 389          * @param $parserOutput null|ParserOutput optional parser output object
 390          *    for efficient access to meta-information about the content object.
 391          *    Provide if you have one handy.
 392          *
 393          * @return array A list of DataUpdate instances that will clean up the
 394          *    database after deletion.
 395          */
 396         public function getDeletionUpdates( WikiPage $page,
 397                 ParserOutput $parserOutput = null )
 398         {
 399                 return array(
 400                         new LinksDeletionUpdate( $page ),
 401                 );
 402         }
 403
 404         /**
 405          * This default implementation always returns false. Subclasses may override this to supply matching logic.
 406          *
 407          * @see Content::matchMagicWord
 408          *
 409          * @since 1.21
 410          *
 411          * @param MagicWord $word
 412          *
 413          * @return bool
 414          */
 415         public function matchMagicWord( MagicWord $word ) {
 416                 return false;
 417         }
 418
 419         /**
 420          * @see Content::convert()
 421          *
 422          * This base implementation calls the hook ConvertContent to enable custom conversions.
 423          * Subclasses may override this to implement conversion for "their" content model.
 424          *
 425          * @param string  $toModel the desired content model, use the CONTENT_MODEL_XXX flags.
 426          * @param string  $lossy flag, set to "lossy" to allow lossy conversion. If lossy conversion is
 427          * not allowed, full round-trip conversion is expected to work without losing information.
 428          *
 429          * @return Content|bool A content object with the content model $toModel, or false if
 430          * that conversion is not supported.
 431          */
 432         public function convert( $toModel, $lossy = '' ) {
 433                 if ( $this->getModel() === $toModel ) {
 434                         //nothing to do, shorten out.
 435                         return $this;
 436                 }
 437
 438                 $lossy = ( $lossy === 'lossy' ); // string flag, convert to boolean for convenience
 439                 $result = false;
 440
 441                 wfRunHooks( 'ConvertContent', array( $this, $toModel, $lossy, &$result ) );
 442                 return $result;
 443         }
 444 }