includes/content/Content.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 interface for content objects.
  31  *
  32  * @ingroup Content
  33  */
  34 interface Content {
  35
  36         /**
  37          * @since 1.21
  38          *
  39          * @return string A string representing the content in a way useful for
  40          *   building a full text search index. If no useful representation exists,
  41          *   this method returns an empty string.
  42          *
  43          * @todo Test that this actually works
  44          * @todo Make sure this also works with LuceneSearch / WikiSearch
  45          */
  46         public function getTextForSearchIndex();
  47
  48         /**
  49          * @since 1.21
  50          *
  51          * @return string|bool The wikitext to include when another page includes this
  52          * content, or false if the content is not includable in a wikitext page.
  53          *
  54          * @todo Allow native handling, bypassing wikitext representation, like
  55          *  for includable special pages.
  56          * @todo Allow transclusion into other content models than Wikitext!
  57          * @todo Used in WikiPage and MessageCache to get message text. Not so
  58          *  nice. What should we use instead?!
  59          */
  60         public function getWikitextForTransclusion();
  61
  62         /**
  63          * Returns a textual representation of the content suitable for use in edit
  64          * summaries and log messages.
  65          *
  66          * @since 1.21
  67          *
  68          * @param int $maxLength Maximum length of the summary text.
  69          *
  70          * @return string The summary text.
  71          */
  72         public function getTextForSummary( $maxLength = 250 );
  73
  74         /**
  75          * Returns native representation of the data. Interpretation depends on
  76          * the data model used, as given by getDataModel().
  77          *
  78          * @since 1.21
  79          *
  80          * @deprecated since 1.33 use getText() for TextContent instances.
  81          *             For other content models, use specialized getters.
  82          *
  83          * @return mixed The native representation of the content. Could be a
  84          *    string, a nested array structure, an object, a binary blob...
  85          *    anything, really.
  86          *
  87          * @note Caller must be aware of content model!
  88          */
  89         public function getNativeData();
  90
  91         /**
  92          * Returns the content's nominal size in "bogo-bytes".
  93          *
  94          * @return int
  95          */
  96         public function getSize();
  97
  98         /**
  99          * Returns the ID of the content model used by this Content object.
 100          * Corresponds to the CONTENT_MODEL_XXX constants.
 101          *
 102          * @since 1.21
 103          *
 104          * @return string The model id
 105          */
 106         public function getModel();
 107
 108         /**
 109          * Convenience method that returns the ContentHandler singleton for handling
 110          * the content model that this Content object uses.
 111          *
 112          * Shorthand for ContentHandler::getForContent( $this )
 113          *
 114          * @since 1.21
 115          *
 116          * @return ContentHandler
 117          */
 118         public function getContentHandler();
 119
 120         /**
 121          * Convenience method that returns the default serialization format for the
 122          * content model that this Content object uses.
 123          *
 124          * Shorthand for $this->getContentHandler()->getDefaultFormat()
 125          *
 126          * @since 1.21
 127          *
 128          * @return string
 129          */
 130         public function getDefaultFormat();
 131
 132         /**
 133          * Convenience method that returns the list of serialization formats
 134          * supported for the content model that this Content object uses.
 135          *
 136          * Shorthand for $this->getContentHandler()->getSupportedFormats()
 137          *
 138          * @since 1.21
 139          *
 140          * @return string[] List of supported serialization formats
 141          */
 142         public function getSupportedFormats();
 143
 144         /**
 145          * Returns true if $format is a supported serialization format for this
 146          * Content object, false if it isn't.
 147          *
 148          * Note that this should always return true if $format is null, because null
 149          * stands for the default serialization.
 150          *
 151          * Shorthand for $this->getContentHandler()->isSupportedFormat( $format )
 152          *
 153          * @since 1.21
 154          *
 155          * @param string $format The serialization format to check.
 156          *
 157          * @return bool Whether the format is supported
 158          */
 159         public function isSupportedFormat( $format );
 160
 161         /**
 162          * Convenience method for serializing this Content object.
 163          *
 164          * Shorthand for $this->getContentHandler()->serializeContent( $this, $format )
 165          *
 166          * @since 1.21
 167          *
 168          * @param string|null $format The desired serialization format, or null for the default format.
 169          *
 170          * @return string Serialized form of this Content object.
 171          */
 172         public function serialize( $format = null );
 173
 174         /**
 175          * Returns true if this Content object represents empty content.
 176          *
 177          * @since 1.21
 178          *
 179          * @return bool Whether this Content object is empty
 180          */
 181         public function isEmpty();
 182
 183         /**
 184          * Returns whether the content is valid. This is intended for local validity
 185          * checks, not considering global consistency.
 186          *
 187          * Content needs to be valid before it can be saved.
 188          *
 189          * This default implementation always returns true.
 190          *
 191          * @since 1.21
 192          *
 193          * @return bool
 194          */
 195         public function isValid();
 196
 197         /**
 198          * Returns true if this Content objects is conceptually equivalent to the
 199          * given Content object.
 200          *
 201          * Contract:
 202          *
 203          * - Will return false if $that is null.
 204          * - Will return true if $that === $this.
 205          * - Will return false if $that->getModel() !== $this->getModel().
 206          * - Will return false if get_class( $that ) !== get_class( $this )
 207          * - Should return false if $that->getModel() == $this->getModel() and
 208          *     $that is not semantically equivalent to $this, according to
 209          *     the data model defined by $this->getModel().
 210          *
 211          * Implementations should be careful to make equals() transitive and reflexive:
 212          *
 213          * - $a->equals( $b ) <=> $b->equals( $a )
 214          * - $a->equals( $b ) &&  $b->equals( $c ) ==> $a->equals( $c )
 215          *
 216          * @since 1.21
 217          *
 218          * @param Content|null $that The Content object to compare to.
 219          *
 220          * @return bool True if this Content object is equal to $that, false otherwise.
 221          */
 222         public function equals( Content $that = null );
 223
 224         /**
 225          * Return a copy of this Content object. The following must be true for the
 226          * object returned:
 227          *
 228          * if $copy = $original->copy()
 229          *
 230          * - get_class($original) === get_class($copy)
 231          * - $original->getModel() === $copy->getModel()
 232          * - $original->equals( $copy )
 233          *
 234          * If and only if the Content object is immutable, the copy() method can and
 235          * should return $this. That is, $copy === $original may be true, but only
 236          * for immutable content objects.
 237          *
 238          * @since 1.21
 239          *
 240          * @return Content A copy of this object
 241          */
 242         public function copy();
 243
 244         /**
 245          * Returns true if this content is countable as a "real" wiki page, provided
 246          * that it's also in a countable location (e.g. a current revision in the
 247          * main namespace).
 248          *
 249          * @see SlotRoleHandler::supportsArticleCount
 250          *
 251          * @since 1.21
 252          *
 253          * @param bool|null $hasLinks If it is known whether this content contains
 254          *    links, provide this information here, to avoid redundant parsing to
 255          *    find out.
 256          *
 257          * @return bool
 258          */
 259         public function isCountable( $hasLinks = null );
 260
 261         /**
 262          * Parse the Content object and generate a ParserOutput from the result.
 263          * $result->getText() can be used to obtain the generated HTML. If no HTML
 264          * is needed, $generateHtml can be set to false; in that case,
 265          * $result->getText() may return null.
 266          *
 267          * @note To control which options are used in the cache key for the
 268          *       generated parser output, implementations of this method
 269          *       may call ParserOutput::recordOption() on the output object.
 270          *
 271          * @param Title $title The page title to use as a context for rendering.
 272          * @param int|null $revId ID of the revision being rendered.
 273          *  See Parser::parse() for the ramifications. (default: null)
 274          * @param ParserOptions|null $options Any parser options.
 275          * @param bool $generateHtml Whether to generate HTML (default: true). If false,
 276          *        the result of calling getText() on the ParserOutput object returned by
 277          *        this method is undefined.
 278          *
 279          * @since 1.21
 280          *
 281          * @return ParserOutput
 282          */
 283         public function getParserOutput( Title $title, $revId = null,
 284                 ParserOptions $options = null, $generateHtml = true );
 285
 286         // TODO: make RenderOutput and RenderOptions base classes
 287
 288         /**
 289          * Returns a list of DataUpdate objects for recording information about this
 290          * Content in some secondary data store. If the optional second argument,
 291          * $old, is given, the updates may model only the changes that need to be
 292          * made to replace information about the old content with information about
 293          * the new content.
 294          *
 295          * @deprecated since 1.32, call and override
 296          *   ContentHandler::getSecondaryDataUpdates instead.
 297          *
 298          * @note Implementations should call the SecondaryDataUpdates hook, like
 299          *   AbstractContent does.
 300          *
 301          * @param Title $title The context for determining the necessary updates
 302          * @param Content|null $old An optional Content object representing the
 303          *    previous content, i.e. the content being replaced by this Content
 304          *    object.
 305          * @param bool $recursive Whether to include recursive updates (default:
 306          *    false).
 307          * @param ParserOutput|null $parserOutput Optional ParserOutput object.
 308          *    Provide if you have one handy, to avoid re-parsing of the content.
 309          *
 310          * @return DataUpdate[] A list of DataUpdate objects for putting information
 311          *    about this content object somewhere.
 312          *
 313          * @since 1.21
 314          */
 315         public function getSecondaryDataUpdates( Title $title, Content $old = null,
 316                 $recursive = true, ParserOutput $parserOutput = null );
 317
 318         /**
 319          * Construct the redirect destination from this content and return an
 320          * array of Titles, or null if this content doesn't represent a redirect.
 321          * The last element in the array is the final destination after all redirects
 322          * have been resolved (up to $wgMaxRedirects times).
 323          *
 324          * @since 1.21
 325          *
 326          * @return Title[]|null List of Titles, with the destination last.
 327          */
 328         public function getRedirectChain();
 329
 330         /**
 331          * Construct the redirect destination from this content and return a Title,
 332          * or null if this content doesn't represent a redirect.
 333          * This will only return the immediate redirect target, useful for
 334          * the redirect table and other checks that don't need full recursion.
 335          *
 336          * @since 1.21
 337          *
 338          * @return Title|null The corresponding Title.
 339          */
 340         public function getRedirectTarget();
 341
 342         /**
 343          * Construct the redirect destination from this content and return the
 344          * Title, or null if this content doesn't represent a redirect.
 345          *
 346          * This will recurse down $wgMaxRedirects times or until a non-redirect
 347          * target is hit in order to provide (hopefully) the Title of the final
 348          * destination instead of another redirect.
 349          *
 350          * There is usually no need to override the default behavior, subclasses that
 351          * want to implement redirects should override getRedirectTarget().
 352          *
 353          * @since 1.21
 354          *
 355          * @return Title|null
 356          */
 357         public function getUltimateRedirectTarget();
 358
 359         /**
 360          * Returns whether this Content represents a redirect.
 361          * Shorthand for getRedirectTarget() !== null.
 362          *
 363          * @see SlotRoleHandler::supportsRedirects
 364          *
 365          * @since 1.21
 366          *
 367          * @return bool
 368          */
 369         public function isRedirect();
 370
 371         /**
 372          * If this Content object is a redirect, this method updates the redirect target.
 373          * Otherwise, it does nothing.
 374          *
 375          * @since 1.21
 376          *
 377          * @param Title $target The new redirect target
 378          *
 379          * @return Content A new Content object with the updated redirect (or $this
 380          *   if this Content object isn't a redirect)
 381          */
 382         public function updateRedirect( Title $target );
 383
 384         /**
 385          * Returns the section with the given ID.
 386          *
 387          * @since 1.21
 388          *
 389          * @param string|int $sectionId Section identifier as a number or string
 390          * (e.g. 0, 1 or 'T-1'). The ID "0" retrieves the section before the first heading, "1" the
 391          * text between the first heading (included) and the second heading (excluded), etc.
 392          *
 393          * @return Content|bool|null The section, or false if no such section
 394          *    exist, or null if sections are not supported.
 395          */
 396         public function getSection( $sectionId );
 397
 398         /**
 399          * Replaces a section of the content and returns a Content object with the
 400          * section replaced.
 401          *
 402          * @since 1.21
 403          *
 404          * @param string|int|null|bool $sectionId Section identifier as a number or string
 405          * (e.g. 0, 1 or 'T-1'), null/false or an empty string for the whole page
 406          * or 'new' for a new section.
 407          * @param Content $with New content of the section
 408          * @param string $sectionTitle New section's subject, only if $section is 'new'
 409          *
 410          * @return string|null Complete article text, or null if error
 411          */
 412         public function replaceSection( $sectionId, Content $with, $sectionTitle = '' );
 413
 414         /**
 415          * Returns a Content object with pre-save transformations applied (or this
 416          * object if no transformations apply).
 417          *
 418          * @since 1.21
 419          *
 420          * @param Title $title
 421          * @param User $user
 422          * @param ParserOptions $parserOptions
 423          *
 424          * @return Content
 425          */
 426         public function preSaveTransform( Title $title, User $user, ParserOptions $parserOptions );
 427
 428         /**
 429          * Returns a new WikitextContent object with the given section heading
 430          * prepended, if supported. The default implementation just returns this
 431          * Content object unmodified, ignoring the section header.
 432          *
 433          * @since 1.21
 434          *
 435          * @param string $header
 436          *
 437          * @return Content
 438          */
 439         public function addSectionHeader( $header );
 440
 441         /**
 442          * Returns a Content object with preload transformations applied (or this
 443          * object if no transformations apply).
 444          *
 445          * @since 1.21
 446          *
 447          * @param Title $title
 448          * @param ParserOptions $parserOptions
 449          * @param array $params
 450          *
 451          * @return Content
 452          */
 453         public function preloadTransform( Title $title, ParserOptions $parserOptions, $params = [] );
 454
 455         /**
 456          * Prepare Content for saving. Called before Content is saved by WikiPage::doEditContent() and in
 457          * similar places.
 458          *
 459          * This may be used to check the content's consistency with global state. This function should
 460          * NOT write any information to the database.
 461          *
 462          * Note that this method will usually be called inside the same transaction
 463          * bracket that will be used to save the new revision.
 464          *
 465          * Note that this method is called before any update to the page table is
 466          * performed. This means that $page may not yet know a page ID.
 467          *
 468          * @since 1.21
 469          *
 470          * @param WikiPage $page The page to be saved.
 471          * @param int $flags Bitfield for use with EDIT_XXX constants, see WikiPage::doEditContent()
 472          * @param int $parentRevId The ID of the current revision
 473          * @param User $user
 474          *
 475          * @return Status A status object indicating whether the content was
 476          *   successfully prepared for saving. If the returned status indicates
 477          *   an error, a rollback will be performed and the transaction aborted.
 478          *
 479          * @see WikiPage::doEditContent()
 480          */
 481         public function prepareSave( WikiPage $page, $flags, $parentRevId, User $user );
 482
 483         /**
 484          * Returns a list of updates to perform when this content is deleted.
 485          * The necessary updates may be taken from the Content object, or depend on
 486          * the current state of the database.
 487          *
 488          * @since 1.21
 489          * @deprecated since 1.32, call and override
 490          *   ContentHandler::getDeletionUpdates instead.
 491          *
 492          * @param WikiPage $page The page the content was deleted from.
 493          * @param ParserOutput|null $parserOutput Optional parser output object
 494          *    for efficient access to meta-information about the content object.
 495          *    Provide if you have one handy.
 496          *
 497          * @return DeferrableUpdate[] A list of DeferrableUpdate instances that will clean up the
 498          *    database after deletion.
 499          */
 500         public function getDeletionUpdates( WikiPage $page,
 501                 ParserOutput $parserOutput = null );
 502
 503         /**
 504          * Returns true if this Content object matches the given magic word.
 505          *
 506          * @since 1.21
 507          *
 508          * @param MagicWord $word The magic word to match
 509          *
 510          * @return bool Whether this Content object matches the given magic word.
 511          */
 512         public function matchMagicWord( MagicWord $word );
 513
 514         /**
 515          * Converts this content object into another content object with the given content model,
 516          * if that is possible.
 517          *
 518          * @param string $toModel The desired content model, use the CONTENT_MODEL_XXX flags.
 519          * @param string $lossy Optional flag, set to "lossy" to allow lossy conversion. If lossy
 520          * conversion is not allowed, full round-trip conversion is expected to work without losing
 521          * information.
 522          *
 523          * @return Content|bool A content object with the content model $toModel, or false if
 524          * that conversion is not supported.
 525          */
 526         public function convert( $toModel, $lossy = '' );
 527         // @todo ImagePage and CategoryPage interfere with per-content action handlers
 528         // @todo nice&sane integration of GeSHi syntax highlighting
 529         //   [11:59] <vvv> Hooks are ugly; make CodeHighlighter interface and a
 530         //   config to set the class which handles syntax highlighting
 531         //   [12:00] <vvv> And default it to a DummyHighlighter
 532
 533 }