includes/Title.php

   1 <?php
   2 /**
   3  * Representation of a title within %MediaWiki.
   4  *
   5  * See title.txt
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License along
  18  * with this program; if not, write to the Free Software Foundation, Inc.,
  19  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  20  * http://www.gnu.org/copyleft/gpl.html
  21  *
  22  * @file
  23  */
  24
  25 use MediaWiki\Permissions\PermissionManager;
  26 use MediaWiki\Storage\RevisionRecord;
  27 use Wikimedia\Assert\Assert;
  28 use Wikimedia\Rdbms\Database;
  29 use Wikimedia\Rdbms\IDatabase;
  30 use MediaWiki\Linker\LinkTarget;
  31 use MediaWiki\Interwiki\InterwikiLookup;
  32 use MediaWiki\MediaWikiServices;
  33
  34 /**
  35  * Represents a title within MediaWiki.
  36  * Optionally may contain an interwiki designation or namespace.
  37  * @note This class can fetch various kinds of data from the database;
  38  *       however, it does so inefficiently.
  39  * @note Consider using a TitleValue object instead. TitleValue is more lightweight
  40  *       and does not rely on global state or the database.
  41  */
  42 class Title implements LinkTarget, IDBAccessObject {
  43         /** @var MapCacheLRU|null */
  44         private static $titleCache = null;
  45
  46         /**
  47          * Title::newFromText maintains a cache to avoid expensive re-normalization of
  48          * commonly used titles. On a batch operation this can become a memory leak
  49          * if not bounded. After hitting this many titles reset the cache.
  50          */
  51         const CACHE_MAX = 1000;
  52
  53         /**
  54          * Used to be GAID_FOR_UPDATE define. Used with getArticleID() and friends
  55          * to use the master DB
  56          */
  57         const GAID_FOR_UPDATE = 1;
  58
  59         /**
  60          * Flag for use with factory methods like newFromLinkTarget() that have
  61          * a $forceClone parameter. If set, the method must return a new instance.
  62          * Without this flag, some factory methods may return existing instances.
  63          *
  64          * @since 1.33
  65          */
  66         const NEW_CLONE = 'clone';
  67
  68         /**
  69          * @name Private member variables
  70          * Please use the accessor functions instead.
  71          * @private
  72          */
  73         // @{
  74
  75         /** @var string Text form (spaces not underscores) of the main part */
  76         public $mTextform = '';
  77
  78         /** @var string URL-encoded form of the main part */
  79         public $mUrlform = '';
  80
  81         /** @var string Main part with underscores */
  82         public $mDbkeyform = '';
  83
  84         /** @var string Database key with the initial letter in the case specified by the user */
  85         protected $mUserCaseDBKey;
  86
  87         /** @var int Namespace index, i.e. one of the NS_xxxx constants */
  88         public $mNamespace = NS_MAIN;
  89
  90         /** @var string Interwiki prefix */
  91         public $mInterwiki = '';
  92
  93         /** @var bool Was this Title created from a string with a local interwiki prefix? */
  94         private $mLocalInterwiki = false;
  95
  96         /** @var string Title fragment (i.e. the bit after the #) */
  97         public $mFragment = '';
  98
  99         /** @var int Article ID, fetched from the link cache on demand */
 100         public $mArticleID = -1;
 101
 102         /** @var bool|int ID of most recent revision */
 103         protected $mLatestID = false;
 104
 105         /**
 106          * @var bool|string ID of the page's content model, i.e. one of the
 107          *   CONTENT_MODEL_XXX constants
 108          */
 109         private $mContentModel = false;
 110
 111         /**
 112          * @var bool If a content model was forced via setContentModel()
 113          *   this will be true to avoid having other code paths reset it
 114          */
 115         private $mForcedContentModel = false;
 116
 117         /** @var int Estimated number of revisions; null of not loaded */
 118         private $mEstimateRevisions;
 119
 120         /** @var array Array of groups allowed to edit this article */
 121         public $mRestrictions = [];
 122
 123         /**
 124          * @var string|bool Comma-separated set of permission keys
 125          * indicating who can move or edit the page from the page table, (pre 1.10) rows.
 126          * Edit and move sections are separated by a colon
 127          * Example: "edit=autoconfirmed,sysop:move=sysop"
 128          */
 129         protected $mOldRestrictions = false;
 130
 131         /** @var bool Cascade restrictions on this page to included templates and images? */
 132         public $mCascadeRestriction;
 133
 134         /** Caching the results of getCascadeProtectionSources */
 135         public $mCascadingRestrictions;
 136
 137         /** @var array When do the restrictions on this page expire? */
 138         protected $mRestrictionsExpiry = [];
 139
 140         /** @var bool Are cascading restrictions in effect on this page? */
 141         protected $mHasCascadingRestrictions;
 142
 143         /** @var array Where are the cascading restrictions coming from on this page? */
 144         public $mCascadeSources;
 145
 146         /** @var bool Boolean for initialisation on demand */
 147         public $mRestrictionsLoaded = false;
 148
 149         /**
 150          * Text form including namespace/interwiki, initialised on demand
 151          *
 152          * Only public to share cache with TitleFormatter
 153          *
 154          * @private
 155          * @var string|null
 156          */
 157         public $prefixedText = null;
 158
 159         /** @var mixed Cached value for getTitleProtection (create protection) */
 160         public $mTitleProtection;
 161
 162         /**
 163          * @var int Namespace index when there is no namespace. Don't change the
 164          *   following default, NS_MAIN is hardcoded in several places. See T2696.
 165          *   Zero except in {{transclusion}} tags.
 166          */
 167         public $mDefaultNamespace = NS_MAIN;
 168
 169         /** @var int The page length, 0 for special pages */
 170         protected $mLength = -1;
 171
 172         /** @var null Is the article at this title a redirect? */
 173         public $mRedirect = null;
 174
 175         /** @var array Associative array of user ID -> timestamp/false */
 176         private $mNotificationTimestamp = [];
 177
 178         /** @var bool Whether a page has any subpages */
 179         private $mHasSubpages;
 180
 181         /** @var bool The (string) language code of the page's language and content code. */
 182         private $mPageLanguage = false;
 183
 184         /** @var string|bool|null The page language code from the database, null if not saved in
 185          * the database or false if not loaded, yet.
 186          */
 187         private $mDbPageLanguage = false;
 188
 189         /** @var TitleValue|null A corresponding TitleValue object */
 190         private $mTitleValue = null;
 191
 192         /** @var bool|null Would deleting this page be a big deletion? */
 193         private $mIsBigDeletion = null;
 194         // @}
 195
 196         /**
 197          * B/C kludge: provide a TitleParser for use by Title.
 198          * Ideally, Title would have no methods that need this.
 199          * Avoid usage of this singleton by using TitleValue
 200          * and the associated services when possible.
 201          *
 202          * @return TitleFormatter
 203          */
 204         private static function getTitleFormatter() {
 205                 return MediaWikiServices::getInstance()->getTitleFormatter();
 206         }
 207
 208         /**
 209          * B/C kludge: provide an InterwikiLookup for use by Title.
 210          * Ideally, Title would have no methods that need this.
 211          * Avoid usage of this singleton by using TitleValue
 212          * and the associated services when possible.
 213          *
 214          * @return InterwikiLookup
 215          */
 216         private static function getInterwikiLookup() {
 217                 return MediaWikiServices::getInstance()->getInterwikiLookup();
 218         }
 219
 220         /**
 221          * @protected
 222          */
 223         function __construct() {
 224         }
 225
 226         /**
 227          * Create a new Title from a prefixed DB key
 228          *
 229          * @param string $key The database key, which has underscores
 230          *      instead of spaces, possibly including namespace and
 231          *      interwiki prefixes
 232          * @return Title|null Title, or null on an error
 233          */
 234         public static function newFromDBkey( $key ) {
 235                 $t = new self();
 236                 $t->mDbkeyform = $key;
 237
 238                 try {
 239                         $t->secureAndSplit();
 240                         return $t;
 241                 } catch ( MalformedTitleException $ex ) {
 242                         return null;
 243                 }
 244         }
 245
 246         /**
 247          * Returns a Title given a TitleValue.
 248          * If the given TitleValue is already a Title instance, that instance is returned,
 249          * unless $forceClone is "clone". If $forceClone is "clone" and the given TitleValue
 250          * is already a Title instance, that instance is copied using the clone operator.
 251          *
 252          * @deprecated since 1.34, use newFromLinkTarget or castFromLinkTarget
 253          *
 254          * @param TitleValue $titleValue Assumed to be safe.
 255          * @param string $forceClone set to NEW_CLONE to ensure a fresh instance is returned.
 256          *
 257          * @return Title
 258          */
 259         public static function newFromTitleValue( TitleValue $titleValue, $forceClone = '' ) {
 260                 return self::newFromLinkTarget( $titleValue, $forceClone );
 261         }
 262
 263         /**
 264          * Returns a Title given a LinkTarget.
 265          * If the given LinkTarget is already a Title instance, that instance is returned,
 266          * unless $forceClone is "clone". If $forceClone is "clone" and the given LinkTarget
 267          * is already a Title instance, that instance is copied using the clone operator.
 268          *
 269          * @param LinkTarget $linkTarget Assumed to be safe.
 270          * @param string $forceClone set to NEW_CLONE to ensure a fresh instance is returned.
 271          *
 272          * @return Title
 273          */
 274         public static function newFromLinkTarget( LinkTarget $linkTarget, $forceClone = '' ) {
 275                 if ( $linkTarget instanceof Title ) {
 276                         // Special case if it's already a Title object
 277                         if ( $forceClone === self::NEW_CLONE ) {
 278                                 return clone $linkTarget;
 279                         } else {
 280                                 return $linkTarget;
 281                         }
 282                 }
 283                 return self::makeTitle(
 284                         $linkTarget->getNamespace(),
 285                         $linkTarget->getText(),
 286                         $linkTarget->getFragment(),
 287                         $linkTarget->getInterwiki()
 288                 );
 289         }
 290
 291         /**
 292          * Same as newFromLinkTarget, but if passed null, returns null.
 293          *
 294          * @param LinkTarget|null $linkTarget Assumed to be safe (if not null).
 295          *
 296          * @return Title|null
 297          */
 298         public static function castFromLinkTarget( $linkTarget ) {
 299                 return $linkTarget ? self::newFromLinkTarget( $linkTarget ) : null;
 300         }
 301
 302         /**
 303          * Create a new Title from text, such as what one would find in a link. De-
 304          * codes any HTML entities in the text.
 305          *
 306          * Title objects returned by this method are guaranteed to be valid, and
 307          * thus return true from the isValid() method.
 308          *
 309          * @note The Title instance returned by this method is not guaranteed to be a fresh instance.
 310          * It may instead be a cached instance created previously, with references to it remaining
 311          * elsewhere.
 312          *
 313          * @param string|int|null $text The link text; spaces, prefixes, and an
 314          *   initial ':' indicating the main namespace are accepted.
 315          * @param int $defaultNamespace The namespace to use if none is specified
 316          *   by a prefix.  If you want to force a specific namespace even if
 317          *   $text might begin with a namespace prefix, use makeTitle() or
 318          *   makeTitleSafe().
 319          * @throws InvalidArgumentException
 320          * @return Title|null Title or null on an error.
 321          */
 322         public static function newFromText( $text, $defaultNamespace = NS_MAIN ) {
 323                 // DWIM: Integers can be passed in here when page titles are used as array keys.
 324                 if ( $text !== null && !is_string( $text ) && !is_int( $text ) ) {
 325                         throw new InvalidArgumentException( '$text must be a string.' );
 326                 }
 327                 if ( $text === null ) {
 328                         return null;
 329                 }
 330
 331                 try {
 332                         return self::newFromTextThrow( (string)$text, $defaultNamespace );
 333                 } catch ( MalformedTitleException $ex ) {
 334                         return null;
 335                 }
 336         }
 337
 338         /**
 339          * Like Title::newFromText(), but throws MalformedTitleException when the title is invalid,
 340          * rather than returning null.
 341          *
 342          * The exception subclasses encode detailed information about why the title is invalid.
 343          *
 344          * Title objects returned by this method are guaranteed to be valid, and
 345          * thus return true from the isValid() method.
 346          *
 347          * @note The Title instance returned by this method is not guaranteed to be a fresh instance.
 348          * It may instead be a cached instance created previously, with references to it remaining
 349          * elsewhere.
 350          *
 351          * @see Title::newFromText
 352          *
 353          * @since 1.25
 354          * @param string $text Title text to check
 355          * @param int $defaultNamespace
 356          * @throws MalformedTitleException If the title is invalid
 357          * @return Title
 358          */
 359         public static function newFromTextThrow( $text, $defaultNamespace = NS_MAIN ) {
 360                 if ( is_object( $text ) ) {
 361                         throw new MWException( '$text must be a string, given an object' );
 362                 } elseif ( $text === null ) {
 363                         // Legacy code relies on MalformedTitleException being thrown in this case
 364                         // (happens when URL with no title in it is parsed). TODO fix
 365                         throw new MalformedTitleException( 'title-invalid-empty' );
 366                 }
 367
 368                 $titleCache = self::getTitleCache();
 369
 370                 // Wiki pages often contain multiple links to the same page.
 371                 // Title normalization and parsing can become expensive on pages with many
 372                 // links, so we can save a little time by caching them.
 373                 // In theory these are value objects and won't get changed...
 374                 if ( $defaultNamespace == NS_MAIN ) {
 375                         $t = $titleCache->get( $text );
 376                         if ( $t ) {
 377                                 return $t;
 378                         }
 379                 }
 380
 381                 // Convert things like &eacute; &#257; or &#x3017; into normalized (T16952) text
 382                 $filteredText = Sanitizer::decodeCharReferencesAndNormalize( $text );
 383
 384                 $t = new Title();
 385                 $t->mDbkeyform = strtr( $filteredText, ' ', '_' );
 386                 $t->mDefaultNamespace = (int)$defaultNamespace;
 387
 388                 $t->secureAndSplit();
 389                 if ( $defaultNamespace == NS_MAIN ) {
 390                         $titleCache->set( $text, $t );
 391                 }
 392                 return $t;
 393         }
 394
 395         /**
 396          * THIS IS NOT THE FUNCTION YOU WANT. Use Title::newFromText().
 397          *
 398          * Example of wrong and broken code:
 399          * $title = Title::newFromURL( $wgRequest->getVal( 'title' ) );
 400          *
 401          * Example of right code:
 402          * $title = Title::newFromText( $wgRequest->getVal( 'title' ) );
 403          *
 404          * Create a new Title from URL-encoded text. Ensures that
 405          * the given title's length does not exceed the maximum.
 406          *
 407          * @param string $url The title, as might be taken from a URL
 408          * @return Title|null The new object, or null on an error
 409          */
 410         public static function newFromURL( $url ) {
 411                 $t = new Title();
 412
 413                 # For compatibility with old buggy URLs. "+" is usually not valid in titles,
 414                 # but some URLs used it as a space replacement and they still come
 415                 # from some external search tools.
 416                 if ( strpos( self::legalChars(), '+' ) === false ) {
 417                         $url = strtr( $url, '+', ' ' );
 418                 }
 419
 420                 $t->mDbkeyform = strtr( $url, ' ', '_' );
 421
 422                 try {
 423                         $t->secureAndSplit();
 424                         return $t;
 425                 } catch ( MalformedTitleException $ex ) {
 426                         return null;
 427                 }
 428         }
 429
 430         /**
 431          * @return MapCacheLRU
 432          */
 433         private static function getTitleCache() {
 434                 if ( self::$titleCache === null ) {
 435                         self::$titleCache = new MapCacheLRU( self::CACHE_MAX );
 436                 }
 437                 return self::$titleCache;
 438         }
 439
 440         /**
 441          * Returns a list of fields that are to be selected for initializing Title
 442          * objects or LinkCache entries. Uses $wgContentHandlerUseDB to determine
 443          * whether to include page_content_model.
 444          *
 445          * @return array
 446          */
 447         protected static function getSelectFields() {
 448                 global $wgContentHandlerUseDB, $wgPageLanguageUseDB;
 449
 450                 $fields = [
 451                         'page_namespace', 'page_title', 'page_id',
 452                         'page_len', 'page_is_redirect', 'page_latest',
 453                 ];
 454
 455                 if ( $wgContentHandlerUseDB ) {
 456                         $fields[] = 'page_content_model';
 457                 }
 458
 459                 if ( $wgPageLanguageUseDB ) {
 460                         $fields[] = 'page_lang';
 461                 }
 462
 463                 return $fields;
 464         }
 465
 466         /**
 467          * Create a new Title from an article ID
 468          *
 469          * @param int $id The page_id corresponding to the Title to create
 470          * @param int $flags Use Title::GAID_FOR_UPDATE to use master
 471          * @return Title|null The new object, or null on an error
 472          */
 473         public static function newFromID( $id, $flags = 0 ) {
 474                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_REPLICA );
 475                 $row = $db->selectRow(
 476                         'page',
 477                         self::getSelectFields(),
 478                         [ 'page_id' => $id ],
 479                         __METHOD__
 480                 );
 481                 if ( $row !== false ) {
 482                         $title = self::newFromRow( $row );
 483                 } else {
 484                         $title = null;
 485                 }
 486
 487                 return $title;
 488         }
 489
 490         /**
 491          * Make an array of titles from an array of IDs
 492          *
 493          * @param int[] $ids Array of IDs
 494          * @return Title[] Array of Titles
 495          */
 496         public static function newFromIDs( $ids ) {
 497                 if ( !count( $ids ) ) {
 498                         return [];
 499                 }
 500                 $dbr = wfGetDB( DB_REPLICA );
 501
 502                 $res = $dbr->select(
 503                         'page',
 504                         self::getSelectFields(),
 505                         [ 'page_id' => $ids ],
 506                         __METHOD__
 507                 );
 508
 509                 $titles = [];
 510                 foreach ( $res as $row ) {
 511                         $titles[] = self::newFromRow( $row );
 512                 }
 513                 return $titles;
 514         }
 515
 516         /**
 517          * Make a Title object from a DB row
 518          *
 519          * @param stdClass $row Object database row (needs at least page_title,page_namespace)
 520          * @return Title Corresponding Title
 521          */
 522         public static function newFromRow( $row ) {
 523                 $t = self::makeTitle( $row->page_namespace, $row->page_title );
 524                 $t->loadFromRow( $row );
 525                 return $t;
 526         }
 527
 528         /**
 529          * Load Title object fields from a DB row.
 530          * If false is given, the title will be treated as non-existing.
 531          *
 532          * @param stdClass|bool $row Database row
 533          */
 534         public function loadFromRow( $row ) {
 535                 if ( $row ) { // page found
 536                         if ( isset( $row->page_id ) ) {
 537                                 $this->mArticleID = (int)$row->page_id;
 538                         }
 539                         if ( isset( $row->page_len ) ) {
 540                                 $this->mLength = (int)$row->page_len;
 541                         }
 542                         if ( isset( $row->page_is_redirect ) ) {
 543                                 $this->mRedirect = (bool)$row->page_is_redirect;
 544                         }
 545                         if ( isset( $row->page_latest ) ) {
 546                                 $this->mLatestID = (int)$row->page_latest;
 547                         }
 548                         if ( !$this->mForcedContentModel && isset( $row->page_content_model ) ) {
 549                                 $this->mContentModel = (string)$row->page_content_model;
 550                         } elseif ( !$this->mForcedContentModel ) {
 551                                 $this->mContentModel = false; # initialized lazily in getContentModel()
 552                         }
 553                         if ( isset( $row->page_lang ) ) {
 554                                 $this->mDbPageLanguage = (string)$row->page_lang;
 555                         }
 556                         if ( isset( $row->page_restrictions ) ) {
 557                                 $this->mOldRestrictions = $row->page_restrictions;
 558                         }
 559                 } else { // page not found
 560                         $this->mArticleID = 0;
 561                         $this->mLength = 0;
 562                         $this->mRedirect = false;
 563                         $this->mLatestID = 0;
 564                         if ( !$this->mForcedContentModel ) {
 565                                 $this->mContentModel = false; # initialized lazily in getContentModel()
 566                         }
 567                 }
 568         }
 569
 570         /**
 571          * Create a new Title from a namespace index and a DB key.
 572          *
 573          * It's assumed that $ns and $title are safe, for instance when
 574          * they came directly from the database or a special page name,
 575          * not from user input.
 576          *
 577          * No validation is applied. For convenience, spaces are normalized
 578          * to underscores, so that e.g. user_text fields can be used directly.
 579          *
 580          * @note This method may return Title objects that are "invalid"
 581          * according to the isValid() method. This is usually caused by
 582          * configuration changes: e.g. a namespace that was once defined is
 583          * no longer configured, or a character that was once allowed in
 584          * titles is now forbidden.
 585          *
 586          * @param int $ns The namespace of the article
 587          * @param string $title The unprefixed database key form
 588          * @param string $fragment The link fragment (after the "#")
 589          * @param string $interwiki The interwiki prefix
 590          * @return Title The new object
 591          */
 592         public static function makeTitle( $ns, $title, $fragment = '', $interwiki = '' ) {
 593                 $t = new Title();
 594                 $t->mInterwiki = $interwiki;
 595                 $t->mFragment = $fragment;
 596                 $t->mNamespace = $ns = (int)$ns;
 597                 $t->mDbkeyform = strtr( $title, ' ', '_' );
 598                 $t->mArticleID = ( $ns >= 0 ) ? -1 : 0;
 599                 $t->mUrlform = wfUrlencode( $t->mDbkeyform );
 600                 $t->mTextform = strtr( $title, '_', ' ' );
 601                 $t->mContentModel = false; # initialized lazily in getContentModel()
 602                 return $t;
 603         }
 604
 605         /**
 606          * Create a new Title from a namespace index and a DB key.
 607          * The parameters will be checked for validity, which is a bit slower
 608          * than makeTitle() but safer for user-provided data.
 609          *
 610          * Title objects returned by makeTitleSafe() are guaranteed to be valid,
 611          * that is, they return true from the isValid() method. If no valid Title
 612          * can be constructed from the input, this method returns null.
 613          *
 614          * @param int $ns The namespace of the article
 615          * @param string $title Database key form
 616          * @param string $fragment The link fragment (after the "#")
 617          * @param string $interwiki Interwiki prefix
 618          * @return Title|null The new object, or null on an error
 619          */
 620         public static function makeTitleSafe( $ns, $title, $fragment = '', $interwiki = '' ) {
 621                 // NOTE: ideally, this would just call makeTitle() and then isValid(),
 622                 // but presently, that means more overhead on a potential performance hotspot.
 623
 624                 if ( !MediaWikiServices::getInstance()->getNamespaceInfo()->exists( $ns ) ) {
 625                         return null;
 626                 }
 627
 628                 $t = new Title();
 629                 $t->mDbkeyform = self::makeName( $ns, $title, $fragment, $interwiki, true );
 630
 631                 try {
 632                         $t->secureAndSplit();
 633                         return $t;
 634                 } catch ( MalformedTitleException $ex ) {
 635                         return null;
 636                 }
 637         }
 638
 639         /**
 640          * Create a new Title for the Main Page
 641          *
 642          * This uses the 'mainpage' interface message, which could be specified in
 643          * `$wgForceUIMsgAsContentMsg`. If that is the case, then calling this method
 644          * will use the user language, which would involve initialising the session
 645          * via `RequestContext::getMain()->getLanguage()`. For session-less endpoints,
 646          * be sure to pass in a MessageLocalizer (such as your own RequestContext,
 647          * or ResourceloaderContext) to prevent an error.
 648          *
 649          * @note The Title instance returned by this method is not guaranteed to be a fresh instance.
 650          * It may instead be a cached instance created previously, with references to it remaining
 651          * elsewhere.
 652          *
 653          * @param MessageLocalizer|null $localizer An optional context to use (since 1.34)
 654          * @return Title
 655          */
 656         public static function newMainPage( MessageLocalizer $localizer = null ) {
 657                 if ( $localizer ) {
 658                         $msg = $localizer->msg( 'mainpage' );
 659                 } else {
 660                         $msg = wfMessage( 'mainpage' );
 661                 }
 662
 663                 $title = self::newFromText( $msg->inContentLanguage()->text() );
 664
 665                 // Every page renders at least one link to the Main Page (e.g. sidebar).
 666                 // If the localised value is invalid, don't produce fatal errors that
 667                 // would make the wiki inaccessible (and hard to fix the invalid message).
 668                 // Gracefully fallback...
 669                 if ( !$title ) {
 670                         $title = self::newFromText( 'Main Page' );
 671                 }
 672                 return $title;
 673         }
 674
 675         /**
 676          * Get the prefixed DB key associated with an ID
 677          *
 678          * @param int $id The page_id of the article
 679          * @return Title|null An object representing the article, or null if no such article was found
 680          */
 681         public static function nameOf( $id ) {
 682                 $dbr = wfGetDB( DB_REPLICA );
 683
 684                 $s = $dbr->selectRow(
 685                         'page',
 686                         [ 'page_namespace', 'page_title' ],
 687                         [ 'page_id' => $id ],
 688                         __METHOD__
 689                 );
 690                 if ( $s === false ) {
 691                         return null;
 692                 }
 693
 694                 $n = self::makeName( $s->page_namespace, $s->page_title );
 695                 return $n;
 696         }
 697
 698         /**
 699          * Get a regex character class describing the legal characters in a link
 700          *
 701          * @return string The list of characters, not delimited
 702          */
 703         public static function legalChars() {
 704                 global $wgLegalTitleChars;
 705                 return $wgLegalTitleChars;
 706         }
 707
 708         /**
 709          * Utility method for converting a character sequence from bytes to Unicode.
 710          *
 711          * Primary usecase being converting $wgLegalTitleChars to a sequence usable in
 712          * javascript, as PHP uses UTF-8 bytes where javascript uses Unicode code units.
 713          *
 714          * @param string $byteClass
 715          * @return string
 716          */
 717         public static function convertByteClassToUnicodeClass( $byteClass ) {
 718                 $length = strlen( $byteClass );
 719                 // Input token queue
 720                 $x0 = $x1 = $x2 = '';
 721                 // Decoded queue
 722                 $d0 = $d1 = $d2 = '';
 723                 // Decoded integer codepoints
 724                 $ord0 = $ord1 = $ord2 = 0;
 725                 // Re-encoded queue
 726                 $r0 = $r1 = $r2 = '';
 727                 // Output
 728                 $out = '';
 729                 // Flags
 730                 $allowUnicode = false;
 731                 for ( $pos = 0; $pos < $length; $pos++ ) {
 732                         // Shift the queues down
 733                         $x2 = $x1;
 734                         $x1 = $x0;
 735                         $d2 = $d1;
 736                         $d1 = $d0;
 737                         $ord2 = $ord1;
 738                         $ord1 = $ord0;
 739                         $r2 = $r1;
 740                         $r1 = $r0;
 741                         // Load the current input token and decoded values
 742                         $inChar = $byteClass[$pos];
 743                         if ( $inChar == '\\' ) {
 744                                 if ( preg_match( '/x([0-9a-fA-F]{2})/A', $byteClass, $m, 0, $pos + 1 ) ) {
 745                                         $x0 = $inChar . $m[0];
 746                                         $d0 = chr( hexdec( $m[1] ) );
 747                                         $pos += strlen( $m[0] );
 748                                 } elseif ( preg_match( '/[0-7]{3}/A', $byteClass, $m, 0, $pos + 1 ) ) {
 749                                         $x0 = $inChar . $m[0];
 750                                         $d0 = chr( octdec( $m[0] ) );
 751                                         $pos += strlen( $m[0] );
 752                                 } elseif ( $pos + 1 >= $length ) {
 753                                         $x0 = $d0 = '\\';
 754                                 } else {
 755                                         $d0 = $byteClass[$pos + 1];
 756                                         $x0 = $inChar . $d0;
 757                                         $pos += 1;
 758                                 }
 759                         } else {
 760                                 $x0 = $d0 = $inChar;
 761                         }
 762                         $ord0 = ord( $d0 );
 763                         // Load the current re-encoded value
 764                         if ( $ord0 < 32 || $ord0 == 0x7f ) {
 765                                 $r0 = sprintf( '\x%02x', $ord0 );
 766                         } elseif ( $ord0 >= 0x80 ) {
 767                                 // Allow unicode if a single high-bit character appears
 768                                 $r0 = sprintf( '\x%02x', $ord0 );
 769                                 $allowUnicode = true;
 770                                 // @phan-suppress-next-line PhanParamSuspiciousOrder false positive
 771                         } elseif ( strpos( '-\\[]^', $d0 ) !== false ) {
 772                                 $r0 = '\\' . $d0;
 773                         } else {
 774                                 $r0 = $d0;
 775                         }
 776                         // Do the output
 777                         if ( $x0 !== '' && $x1 === '-' && $x2 !== '' ) {
 778                                 // Range
 779                                 if ( $ord2 > $ord0 ) {
 780                                         // Empty range
 781                                 } elseif ( $ord0 >= 0x80 ) {
 782                                         // Unicode range
 783                                         $allowUnicode = true;
 784                                         if ( $ord2 < 0x80 ) {
 785                                                 // Keep the non-unicode section of the range
 786                                                 $out .= "$r2-\\x7F";
 787                                         }
 788                                 } else {
 789                                         // Normal range
 790                                         $out .= "$r2-$r0";
 791                                 }
 792                                 // Reset state to the initial value
 793                                 $x0 = $x1 = $d0 = $d1 = $r0 = $r1 = '';
 794                         } elseif ( $ord2 < 0x80 ) {
 795                                 // ASCII character
 796                                 $out .= $r2;
 797                         }
 798                 }
 799                 if ( $ord1 < 0x80 ) {
 800                         $out .= $r1;
 801                 }
 802                 if ( $ord0 < 0x80 ) {
 803                         $out .= $r0;
 804                 }
 805                 if ( $allowUnicode ) {
 806                         $out .= '\u0080-\uFFFF';
 807                 }
 808                 return $out;
 809         }
 810
 811         /**
 812          * Make a prefixed DB key from a DB key and a namespace index
 813          *
 814          * @param int $ns Numerical representation of the namespace
 815          * @param string $title The DB key form the title
 816          * @param string $fragment The link fragment (after the "#")
 817          * @param string $interwiki The interwiki prefix
 818          * @param bool $canonicalNamespace If true, use the canonical name for
 819          *   $ns instead of the localized version.
 820          * @return string The prefixed form of the title
 821          */
 822         public static function makeName( $ns, $title, $fragment = '', $interwiki = '',
 823                 $canonicalNamespace = false
 824         ) {
 825                 if ( $canonicalNamespace ) {
 826                         $namespace = MediaWikiServices::getInstance()->getNamespaceInfo()->
 827                                 getCanonicalName( $ns );
 828                 } else {
 829                         $namespace = MediaWikiServices::getInstance()->getContentLanguage()->getNsText( $ns );
 830                 }
 831                 $name = $namespace == '' ? $title : "$namespace:$title";
 832                 if ( strval( $interwiki ) != '' ) {
 833                         $name = "$interwiki:$name";
 834                 }
 835                 if ( strval( $fragment ) != '' ) {
 836                         $name .= '#' . $fragment;
 837                 }
 838                 return $name;
 839         }
 840
 841         /**
 842          * Callback for usort() to do title sorts by (namespace, title)
 843          *
 844          * @param LinkTarget $a
 845          * @param LinkTarget $b
 846          *
 847          * @return int Result of string comparison, or namespace comparison
 848          */
 849         public static function compare( LinkTarget $a, LinkTarget $b ) {
 850                 return $a->getNamespace() <=> $b->getNamespace()
 851                         ?: strcmp( $a->getText(), $b->getText() );
 852         }
 853
 854         /**
 855          * Returns true if the title is valid, false if it is invalid.
 856          *
 857          * Valid titles can be round-tripped via makeTitle() and newFromText().
 858          * Their DB key can be used in the database, though it may not have the correct
 859          * capitalization.
 860          *
 861          * Invalid titles may get returned from makeTitle(), and it may be useful to
 862          * allow them to exist, e.g. in order to process log entries about pages in
 863          * namespaces that belong to extensions that are no longer installed.
 864          *
 865          * @note This method is relatively expensive. When constructing Title
 866          * objects that need to be valid, use an instantiator method that is guaranteed
 867          * to return valid titles, such as makeTitleSafe() or newFromText().
 868          *
 869          * @return bool
 870          */
 871         public function isValid() {
 872                 $services = MediaWikiServices::getInstance();
 873                 if ( !$services->getNamespaceInfo()->exists( $this->mNamespace ) ) {
 874                         return false;
 875                 }
 876
 877                 try {
 878                         $services->getTitleParser()->parseTitle( $this->mDbkeyform, $this->mNamespace );
 879                 } catch ( MalformedTitleException $ex ) {
 880                         return false;
 881                 }
 882
 883                 try {
 884                         // Title value applies basic syntax checks. Should perhaps be moved elsewhere.
 885                         new TitleValue(
 886                                 $this->mNamespace,
 887                                 $this->mDbkeyform,
 888                                 $this->mFragment,
 889                                 $this->mInterwiki
 890                         );
 891                 } catch ( InvalidArgumentException $ex ) {
 892                         return false;
 893                 }
 894
 895                 return true;
 896         }
 897
 898         /**
 899          * Determine whether the object refers to a page within
 900          * this project (either this wiki or a wiki with a local
 901          * interwiki, see https://www.mediawiki.org/wiki/Manual:Interwiki_table#iw_local )
 902          *
 903          * @return bool True if this is an in-project interwiki link or a wikilink, false otherwise
 904          */
 905         public function isLocal() {
 906                 if ( $this->isExternal() ) {
 907                         $iw = self::getInterwikiLookup()->fetch( $this->mInterwiki );
 908                         if ( $iw ) {
 909                                 return $iw->isLocal();
 910                         }
 911                 }
 912                 return true;
 913         }
 914
 915         /**
 916          * Is this Title interwiki?
 917          *
 918          * @return bool
 919          */
 920         public function isExternal() {
 921                 return $this->mInterwiki !== '';
 922         }
 923
 924         /**
 925          * Get the interwiki prefix
 926          *
 927          * Use Title::isExternal to check if a interwiki is set
 928          *
 929          * @return string Interwiki prefix
 930          */
 931         public function getInterwiki() {
 932                 return $this->mInterwiki;
 933         }
 934
 935         /**
 936          * Was this a local interwiki link?
 937          *
 938          * @return bool
 939          */
 940         public function wasLocalInterwiki() {
 941                 return $this->mLocalInterwiki;
 942         }
 943
 944         /**
 945          * Determine whether the object refers to a page within
 946          * this project and is transcludable.
 947          *
 948          * @return bool True if this is transcludable
 949          */
 950         public function isTrans() {
 951                 if ( !$this->isExternal() ) {
 952                         return false;
 953                 }
 954
 955                 return self::getInterwikiLookup()->fetch( $this->mInterwiki )->isTranscludable();
 956         }
 957
 958         /**
 959          * Returns the DB name of the distant wiki which owns the object.
 960          *
 961          * @return string|false The DB name
 962          */
 963         public function getTransWikiID() {
 964                 if ( !$this->isExternal() ) {
 965                         return false;
 966                 }
 967
 968                 return self::getInterwikiLookup()->fetch( $this->mInterwiki )->getWikiID();
 969         }
 970
 971         /**
 972          * Get a TitleValue object representing this Title.
 973          *
 974          * @note Not all valid Titles have a corresponding valid TitleValue
 975          * (e.g. TitleValues cannot represent page-local links that have a
 976          * fragment but no title text).
 977          *
 978          * @return TitleValue|null
 979          */
 980         public function getTitleValue() {
 981                 if ( $this->mTitleValue === null ) {
 982                         try {
 983                                 $this->mTitleValue = new TitleValue(
 984                                         $this->mNamespace,
 985                                         $this->mDbkeyform,
 986                                         $this->mFragment,
 987                                         $this->mInterwiki
 988                                 );
 989                         } catch ( InvalidArgumentException $ex ) {
 990                                 wfDebug( __METHOD__ . ': Can\'t create a TitleValue for [[' .
 991                                         $this->getPrefixedText() . ']]: ' . $ex->getMessage() . "\n" );
 992                         }
 993                 }
 994
 995                 return $this->mTitleValue;
 996         }
 997
 998         /**
 999          * Get the text form (spaces not underscores) of the main part
1000          *
1001          * @return string Main part of the title
1002          */
1003         public function getText() {
1004                 return $this->mTextform;
1005         }
1006
1007         /**
1008          * Get the URL-encoded form of the main part
1009          *
1010          * @return string Main part of the title, URL-encoded
1011          */
1012         public function getPartialURL() {
1013                 return $this->mUrlform;
1014         }
1015
1016         /**
1017          * Get the main part with underscores
1018          *
1019          * @return string Main part of the title, with underscores
1020          */
1021         public function getDBkey() {
1022                 return $this->mDbkeyform;
1023         }
1024
1025         /**
1026          * Get the DB key with the initial letter case as specified by the user
1027          * @deprecated since 1.33; please use Title::getDBKey() instead
1028          *
1029          * @return string DB key
1030          */
1031         function getUserCaseDBKey() {
1032                 if ( !is_null( $this->mUserCaseDBKey ) ) {
1033                         return $this->mUserCaseDBKey;
1034                 } else {
1035                         // If created via makeTitle(), $this->mUserCaseDBKey is not set.
1036                         return $this->mDbkeyform;
1037                 }
1038         }
1039
1040         /**
1041          * Get the namespace index, i.e. one of the NS_xxxx constants.
1042          *
1043          * @return int Namespace index
1044          */
1045         public function getNamespace() {
1046                 return $this->mNamespace;
1047         }
1048
1049         /**
1050          * Get the page's content model id, see the CONTENT_MODEL_XXX constants.
1051          *
1052          * @todo Deprecate this in favor of SlotRecord::getModel()
1053          *
1054          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
1055          * @return string Content model id
1056          */
1057         public function getContentModel( $flags = 0 ) {
1058                 if ( !$this->mForcedContentModel
1059                         && ( !$this->mContentModel || $flags === self::GAID_FOR_UPDATE )
1060                         && $this->getArticleID( $flags )
1061                 ) {
1062                         $linkCache = MediaWikiServices::getInstance()->getLinkCache();
1063                         $linkCache->addLinkObj( $this ); # in case we already had an article ID
1064                         $this->mContentModel = $linkCache->getGoodLinkFieldObj( $this, 'model' );
1065                 }
1066
1067                 if ( !$this->mContentModel ) {
1068                         $this->mContentModel = ContentHandler::getDefaultModelFor( $this );
1069                 }
1070
1071                 return $this->mContentModel;
1072         }
1073
1074         /**
1075          * Convenience method for checking a title's content model name
1076          *
1077          * @param string $id The content model ID (use the CONTENT_MODEL_XXX constants).
1078          * @return bool True if $this->getContentModel() == $id
1079          */
1080         public function hasContentModel( $id ) {
1081                 return $this->getContentModel() == $id;
1082         }
1083
1084         /**
1085          * Set a proposed content model for the page for permissions
1086          * checking. This does not actually change the content model
1087          * of a title!
1088          *
1089          * Additionally, you should make sure you've checked
1090          * ContentHandler::canBeUsedOn() first.
1091          *
1092          * @since 1.28
1093          * @param string $model CONTENT_MODEL_XXX constant
1094          */
1095         public function setContentModel( $model ) {
1096                 $this->mContentModel = $model;
1097                 $this->mForcedContentModel = true;
1098         }
1099
1100         /**
1101          * Get the namespace text
1102          *
1103          * @return string|false Namespace text
1104          */
1105         public function getNsText() {
1106                 if ( $this->isExternal() ) {
1107                         // This probably shouldn't even happen, except for interwiki transclusion.
1108                         // If possible, use the canonical name for the foreign namespace.
1109                         $nsText = MediaWikiServices::getInstance()->getNamespaceInfo()->
1110                                 getCanonicalName( $this->mNamespace );
1111                         if ( $nsText !== false ) {
1112                                 return $nsText;
1113                         }
1114                 }
1115
1116                 try {
1117                         $formatter = self::getTitleFormatter();
1118                         return $formatter->getNamespaceName( $this->mNamespace, $this->mDbkeyform );
1119                 } catch ( InvalidArgumentException $ex ) {
1120                         wfDebug( __METHOD__ . ': ' . $ex->getMessage() . "\n" );
1121                         return false;
1122                 }
1123         }
1124
1125         /**
1126          * Get the namespace text of the subject (rather than talk) page
1127          *
1128          * @return string Namespace text
1129          */
1130         public function getSubjectNsText() {
1131                 $services = MediaWikiServices::getInstance();
1132                 return $services->getContentLanguage()->
1133                         getNsText( $services->getNamespaceInfo()->getSubject( $this->mNamespace ) );
1134         }
1135
1136         /**
1137          * Get the namespace text of the talk page
1138          *
1139          * @return string Namespace text
1140          */
1141         public function getTalkNsText() {
1142                 $services = MediaWikiServices::getInstance();
1143                 return $services->getContentLanguage()->
1144                         getNsText( $services->getNamespaceInfo()->getTalk( $this->mNamespace ) );
1145         }
1146
1147         /**
1148          * Can this title have a corresponding talk page?
1149          *
1150          * False for relative section links (with getText() === ''),
1151          * interwiki links (with getInterwiki() !== ''), and pages in NS_SPECIAL.
1152          *
1153          * @see NamespaceInfo::canHaveTalkPage
1154          * @since 1.30
1155          *
1156          * @return bool True if this title either is a talk page or can have a talk page associated.
1157          */
1158         public function canHaveTalkPage() {
1159                 return MediaWikiServices::getInstance()->getNamespaceInfo()->canHaveTalkPage( $this );
1160         }
1161
1162         /**
1163          * Is this in a namespace that allows actual pages?
1164          *
1165          * @return bool
1166          */
1167         public function canExist() {
1168                 return $this->mNamespace >= NS_MAIN;
1169         }
1170
1171         /**
1172          * Can this title be added to a user's watchlist?
1173          *
1174          * False for relative section links (with getText() === ''),
1175          * interwiki links (with getInterwiki() !== ''), and pages in NS_SPECIAL.
1176          *
1177          * @return bool
1178          */
1179         public function isWatchable() {
1180                 $nsInfo = MediaWikiServices::getInstance()->getNamespaceInfo();
1181                 return $this->getText() !== '' && !$this->isExternal() &&
1182                         $nsInfo->isWatchable( $this->mNamespace );
1183         }
1184
1185         /**
1186          * Returns true if this is a special page.
1187          *
1188          * @return bool
1189          */
1190         public function isSpecialPage() {
1191                 return $this->mNamespace == NS_SPECIAL;
1192         }
1193
1194         /**
1195          * Returns true if this title resolves to the named special page
1196          *
1197          * @param string $name The special page name
1198          * @return bool
1199          */
1200         public function isSpecial( $name ) {
1201                 if ( $this->isSpecialPage() ) {
1202                         list( $thisName, /* $subpage */ ) =
1203                                 MediaWikiServices::getInstance()->getSpecialPageFactory()->
1204                                         resolveAlias( $this->mDbkeyform );
1205                         if ( $name == $thisName ) {
1206                                 return true;
1207                         }
1208                 }
1209                 return false;
1210         }
1211
1212         /**
1213          * If the Title refers to a special page alias which is not the local default, resolve
1214          * the alias, and localise the name as necessary.  Otherwise, return $this
1215          *
1216          * @return Title
1217          */
1218         public function fixSpecialName() {
1219                 if ( $this->isSpecialPage() ) {
1220                         $spFactory = MediaWikiServices::getInstance()->getSpecialPageFactory();
1221                         list( $canonicalName, $par ) = $spFactory->resolveAlias( $this->mDbkeyform );
1222                         if ( $canonicalName ) {
1223                                 $localName = $spFactory->getLocalNameFor( $canonicalName, $par );
1224                                 if ( $localName != $this->mDbkeyform ) {
1225                                         return self::makeTitle( NS_SPECIAL, $localName );
1226                                 }
1227                         }
1228                 }
1229                 return $this;
1230         }
1231
1232         /**
1233          * Returns true if the title is inside the specified namespace.
1234          *
1235          * Please make use of this instead of comparing to getNamespace()
1236          * This function is much more resistant to changes we may make
1237          * to namespaces than code that makes direct comparisons.
1238          * @param int $ns The namespace
1239          * @return bool
1240          * @since 1.19
1241          */
1242         public function inNamespace( $ns ) {
1243                 return MediaWikiServices::getInstance()->getNamespaceInfo()->
1244                         equals( $this->mNamespace, $ns );
1245         }
1246
1247         /**
1248          * Returns true if the title is inside one of the specified namespaces.
1249          *
1250          * @param int|int[] $namespaces,... The namespaces to check for
1251          * @return bool
1252          * @since 1.19
1253          */
1254         public function inNamespaces( /* ... */ ) {
1255                 $namespaces = func_get_args();
1256                 if ( count( $namespaces ) > 0 && is_array( $namespaces[0] ) ) {
1257                         $namespaces = $namespaces[0];
1258                 }
1259
1260                 foreach ( $namespaces as $ns ) {
1261                         if ( $this->inNamespace( $ns ) ) {
1262                                 return true;
1263                         }
1264                 }
1265
1266                 return false;
1267         }
1268
1269         /**
1270          * Returns true if the title has the same subject namespace as the
1271          * namespace specified.
1272          * For example this method will take NS_USER and return true if namespace
1273          * is either NS_USER or NS_USER_TALK since both of them have NS_USER
1274          * as their subject namespace.
1275          *
1276          * This is MUCH simpler than individually testing for equivalence
1277          * against both NS_USER and NS_USER_TALK, and is also forward compatible.
1278          * @since 1.19
1279          * @param int $ns
1280          * @return bool
1281          */
1282         public function hasSubjectNamespace( $ns ) {
1283                 return MediaWikiServices::getInstance()->getNamespaceInfo()->
1284                         subjectEquals( $this->mNamespace, $ns );
1285         }
1286
1287         /**
1288          * Is this Title in a namespace which contains content?
1289          * In other words, is this a content page, for the purposes of calculating
1290          * statistics, etc?
1291          *
1292          * @return bool
1293          */
1294         public function isContentPage() {
1295                 return MediaWikiServices::getInstance()->getNamespaceInfo()->
1296                         isContent( $this->mNamespace );
1297         }
1298
1299         /**
1300          * Would anybody with sufficient privileges be able to move this page?
1301          * Some pages just aren't movable.
1302          *
1303          * @return bool
1304          */
1305         public function isMovable() {
1306                 if (
1307                         !MediaWikiServices::getInstance()->getNamespaceInfo()->
1308                                 isMovable( $this->mNamespace ) || $this->isExternal()
1309                 ) {
1310                         // Interwiki title or immovable namespace. Hooks don't get to override here
1311                         return false;
1312                 }
1313
1314                 $result = true;
1315                 Hooks::run( 'TitleIsMovable', [ $this, &$result ] );
1316                 return $result;
1317         }
1318
1319         /**
1320          * Is this the mainpage?
1321          * @note Title::newFromText seems to be sufficiently optimized by the title
1322          * cache that we don't need to over-optimize by doing direct comparisons and
1323          * accidentally creating new bugs where $title->equals( Title::newFromText() )
1324          * ends up reporting something differently than $title->isMainPage();
1325          *
1326          * @since 1.18
1327          * @return bool
1328          */
1329         public function isMainPage() {
1330                 return $this->equals( self::newMainPage() );
1331         }
1332
1333         /**
1334          * Is this a subpage?
1335          *
1336          * @return bool
1337          */
1338         public function isSubpage() {
1339                 return MediaWikiServices::getInstance()->getNamespaceInfo()->
1340                         hasSubpages( $this->mNamespace )
1341                         ? strpos( $this->getText(), '/' ) !== false
1342                         : false;
1343         }
1344
1345         /**
1346          * Is this a conversion table for the LanguageConverter?
1347          *
1348          * @return bool
1349          */
1350         public function isConversionTable() {
1351                 // @todo ConversionTable should become a separate content model.
1352
1353                 return $this->mNamespace == NS_MEDIAWIKI &&
1354                         strpos( $this->getText(), 'Conversiontable/' ) === 0;
1355         }
1356
1357         /**
1358          * Does that page contain wikitext, or it is JS, CSS or whatever?
1359          *
1360          * @return bool
1361          */
1362         public function isWikitextPage() {
1363                 return $this->hasContentModel( CONTENT_MODEL_WIKITEXT );
1364         }
1365
1366         /**
1367          * Could this MediaWiki namespace page contain custom CSS, JSON, or JavaScript for the
1368          * global UI. This is generally true for pages in the MediaWiki namespace having
1369          * CONTENT_MODEL_CSS, CONTENT_MODEL_JSON, or CONTENT_MODEL_JAVASCRIPT.
1370          *
1371          * This method does *not* return true for per-user JS/JSON/CSS. Use isUserConfigPage()
1372          * for that!
1373          *
1374          * Note that this method should not return true for pages that contain and show
1375          * "inactive" CSS, JSON, or JS.
1376          *
1377          * @return bool
1378          * @since 1.31
1379          */
1380         public function isSiteConfigPage() {
1381                 return (
1382                         $this->isSiteCssConfigPage()
1383                         || $this->isSiteJsonConfigPage()
1384                         || $this->isSiteJsConfigPage()
1385                 );
1386         }
1387
1388         /**
1389          * Is this a "config" (.css, .json, or .js) sub-page of a user page?
1390          *
1391          * @return bool
1392          * @since 1.31
1393          */
1394         public function isUserConfigPage() {
1395                 return (
1396                         $this->isUserCssConfigPage()
1397                         || $this->isUserJsonConfigPage()
1398                         || $this->isUserJsConfigPage()
1399                 );
1400         }
1401
1402         /**
1403          * Trim down a .css, .json, or .js subpage title to get the corresponding skin name
1404          *
1405          * @return string Containing skin name from .css, .json, or .js subpage title
1406          * @since 1.31
1407          */
1408         public function getSkinFromConfigSubpage() {
1409                 $subpage = explode( '/', $this->mTextform );
1410                 $subpage = $subpage[count( $subpage ) - 1];
1411                 $lastdot = strrpos( $subpage, '.' );
1412                 if ( $lastdot === false ) {
1413                         return $subpage; # Never happens: only called for names ending in '.css'/'.json'/'.js'
1414                 }
1415                 return substr( $subpage, 0, $lastdot );
1416         }
1417
1418         /**
1419          * Is this a CSS "config" sub-page of a user page?
1420          *
1421          * @return bool
1422          * @since 1.31
1423          */
1424         public function isUserCssConfigPage() {
1425                 return (
1426                         NS_USER == $this->mNamespace
1427                         && $this->isSubpage()
1428                         && $this->hasContentModel( CONTENT_MODEL_CSS )
1429                 );
1430         }
1431
1432         /**
1433          * Is this a JSON "config" sub-page of a user page?
1434          *
1435          * @return bool
1436          * @since 1.31
1437          */
1438         public function isUserJsonConfigPage() {
1439                 return (
1440                         NS_USER == $this->mNamespace
1441                         && $this->isSubpage()
1442                         && $this->hasContentModel( CONTENT_MODEL_JSON )
1443                 );
1444         }
1445
1446         /**
1447          * Is this a JS "config" sub-page of a user page?
1448          *
1449          * @return bool
1450          * @since 1.31
1451          */
1452         public function isUserJsConfigPage() {
1453                 return (
1454                         NS_USER == $this->mNamespace
1455                         && $this->isSubpage()
1456                         && $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT )
1457                 );
1458         }
1459
1460         /**
1461          * Is this a sitewide CSS "config" page?
1462          *
1463          * @return bool
1464          * @since 1.32
1465          */
1466         public function isSiteCssConfigPage() {
1467                 return (
1468                         NS_MEDIAWIKI == $this->mNamespace
1469                         && (
1470                                 $this->hasContentModel( CONTENT_MODEL_CSS )
1471                                 // paranoia - a MediaWiki: namespace page with mismatching extension and content
1472                                 // model is probably by mistake and might get handled incorrectly (see e.g. T112937)
1473                                 || substr( $this->mDbkeyform, -4 ) === '.css'
1474                         )
1475                 );
1476         }
1477
1478         /**
1479          * Is this a sitewide JSON "config" page?
1480          *
1481          * @return bool
1482          * @since 1.32
1483          */
1484         public function isSiteJsonConfigPage() {
1485                 return (
1486                         NS_MEDIAWIKI == $this->mNamespace
1487                         && (
1488                                 $this->hasContentModel( CONTENT_MODEL_JSON )
1489                                 // paranoia - a MediaWiki: namespace page with mismatching extension and content
1490                                 // model is probably by mistake and might get handled incorrectly (see e.g. T112937)
1491                                 || substr( $this->mDbkeyform, -5 ) === '.json'
1492                         )
1493                 );
1494         }
1495
1496         /**
1497          * Is this a sitewide JS "config" page?
1498          *
1499          * @return bool
1500          * @since 1.31
1501          */
1502         public function isSiteJsConfigPage() {
1503                 return (
1504                         NS_MEDIAWIKI == $this->mNamespace
1505                         && (
1506                                 $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT )
1507                                 // paranoia - a MediaWiki: namespace page with mismatching extension and content
1508                                 // model is probably by mistake and might get handled incorrectly (see e.g. T112937)
1509                                 || substr( $this->mDbkeyform, -3 ) === '.js'
1510                         )
1511                 );
1512         }
1513
1514         /**
1515          * Is this a message which can contain raw HTML?
1516          *
1517          * @return bool
1518          * @since 1.32
1519          */
1520         public function isRawHtmlMessage() {
1521                 global $wgRawHtmlMessages;
1522
1523                 if ( !$this->inNamespace( NS_MEDIAWIKI ) ) {
1524                         return false;
1525                 }
1526                 $message = lcfirst( $this->getRootTitle()->getDBkey() );
1527                 return in_array( $message, $wgRawHtmlMessages, true );
1528         }
1529
1530         /**
1531          * Is this a talk page of some sort?
1532          *
1533          * @return bool
1534          */
1535         public function isTalkPage() {
1536                 return MediaWikiServices::getInstance()->getNamespaceInfo()->
1537                         isTalk( $this->mNamespace );
1538         }
1539
1540         /**
1541          * Get a Title object associated with the talk page of this article
1542          *
1543          * @deprecated since 1.34, use getTalkPageIfDefined() or NamespaceInfo::getTalkPage()
1544          *             with NamespaceInfo::canHaveTalkPage(). Note that the new method will
1545          *             throw if asked for the talk page of a section-only link, or of an interwiki
1546          *             link.
1547          * @return Title The object for the talk page
1548          * @throws MWException if $target doesn't have talk pages, e.g. because it's in NS_SPECIAL
1549          *         or because it's a relative link, or an interwiki link.
1550          */
1551         public function getTalkPage() {
1552                 // NOTE: The equivalent code in NamespaceInfo is less lenient about producing invalid titles.
1553                 //       Instead of failing on invalid titles, let's just log the issue for now.
1554                 //       See the discussion on T227817.
1555
1556                 // Is this the same title?
1557                 $talkNS = MediaWikiServices::getInstance()->getNamespaceInfo()->getTalk( $this->mNamespace );
1558                 if ( $this->mNamespace == $talkNS ) {
1559                         return $this;
1560                 }
1561
1562                 $title = self::makeTitle( $talkNS, $this->mDbkeyform );
1563
1564                 $this->warnIfPageCannotExist( $title, __METHOD__ );
1565
1566                 return $title;
1567                 // TODO: replace the above with the code below:
1568                 // return self::castFromLinkTarget(
1569                 // MediaWikiServices::getInstance()->getNamespaceInfo()->getTalkPage( $this ) );
1570         }
1571
1572         /**
1573          * Get a Title object associated with the talk page of this article,
1574          * if such a talk page can exist.
1575          *
1576          * @since 1.30
1577          *
1578          * @return Title|null The object for the talk page,
1579          *         or null if no associated talk page can exist, according to canHaveTalkPage().
1580          */
1581         public function getTalkPageIfDefined() {
1582                 if ( !$this->canHaveTalkPage() ) {
1583                         return null;
1584                 }
1585
1586                 return $this->getTalkPage();
1587         }
1588
1589         /**
1590          * Get a title object associated with the subject page of this
1591          * talk page
1592          *
1593          * @deprecated since 1.34, use NamespaceInfo::getSubjectPage
1594          * @return Title The object for the subject page
1595          */
1596         public function getSubjectPage() {
1597                 // Is this the same title?
1598                 $subjectNS = MediaWikiServices::getInstance()->getNamespaceInfo()
1599                         ->getSubject( $this->mNamespace );
1600                 if ( $this->mNamespace == $subjectNS ) {
1601                         return $this;
1602                 }
1603                 // NOTE: The equivalent code in NamespaceInfo is less lenient about producing invalid titles.
1604                 //       Instead of failing on invalid titles, let's just log the issue for now.
1605                 //       See the discussion on T227817.
1606                 $title = self::makeTitle( $subjectNS, $this->mDbkeyform );
1607
1608                 $this->warnIfPageCannotExist( $title, __METHOD__ );
1609
1610                 return $title;
1611                 // TODO: replace the above with the code below:
1612                 // return self::castFromLinkTarget(
1613                 // MediaWikiServices::getInstance()->getNamespaceInfo()->getSubjectPage( $this ) );
1614         }
1615
1616         /**
1617          * @param Title $title
1618          * @param string $method
1619          *
1620          * @return bool whether a warning was issued
1621          */
1622         private function warnIfPageCannotExist( Title $title, $method ) {
1623                 if ( $this->getText() == '' ) {
1624                         wfLogWarning(
1625                                 $method . ': called on empty title ' . $this->getFullText() . ', returning '
1626                                 . $title->getFullText()
1627                         );
1628
1629                         return true;
1630                 }
1631
1632                 if ( $this->getInterwiki() !== '' ) {
1633                         wfLogWarning(
1634                                 $method . ': called on interwiki title ' . $this->getFullText() . ', returning '
1635                                 . $title->getFullText()
1636                         );
1637
1638                         return true;
1639                 }
1640
1641                 return false;
1642         }
1643
1644         /**
1645          * Get the other title for this page, if this is a subject page
1646          * get the talk page, if it is a subject page get the talk page
1647          *
1648          * @deprecated since 1.34, use NamespaceInfo::getAssociatedPage
1649          * @since 1.25
1650          * @throws MWException If the page doesn't have an other page
1651          * @return Title
1652          */
1653         public function getOtherPage() {
1654                 // NOTE: Depend on the methods in this class instead of their equivalent in NamespaceInfo,
1655                 //       until their semantics has become exactly the same.
1656                 //       See the discussion on T227817.
1657                 if ( $this->isSpecialPage() ) {
1658                         throw new MWException( 'Special pages cannot have other pages' );
1659                 }
1660                 if ( $this->isTalkPage() ) {
1661                         return $this->getSubjectPage();
1662                 } else {
1663                         if ( !$this->canHaveTalkPage() ) {
1664                                 throw new MWException( "{$this->getPrefixedText()} does not have an other page" );
1665                         }
1666                         return $this->getTalkPage();
1667                 }
1668                 // TODO: replace the above with the code below:
1669                 // return self::castFromLinkTarget(
1670                 // MediaWikiServices::getInstance()->getNamespaceInfo()->getAssociatedPage( $this ) );
1671         }
1672
1673         /**
1674          * Get the default namespace index, for when there is no namespace
1675          *
1676          * @return int Default namespace index
1677          */
1678         public function getDefaultNamespace() {
1679                 return $this->mDefaultNamespace;
1680         }
1681
1682         /**
1683          * Get the Title fragment (i.e.\ the bit after the #) in text form
1684          *
1685          * Use Title::hasFragment to check for a fragment
1686          *
1687          * @return string Title fragment
1688          */
1689         public function getFragment() {
1690                 return $this->mFragment;
1691         }
1692
1693         /**
1694          * Check if a Title fragment is set
1695          *
1696          * @return bool
1697          * @since 1.23
1698          */
1699         public function hasFragment() {
1700                 return $this->mFragment !== '';
1701         }
1702
1703         /**
1704          * Get the fragment in URL form, including the "#" character if there is one
1705          *
1706          * @return string Fragment in URL form
1707          */
1708         public function getFragmentForURL() {
1709                 if ( !$this->hasFragment() ) {
1710                         return '';
1711                 } elseif ( $this->isExternal() ) {
1712                         // Note: If the interwiki is unknown, it's treated as a namespace on the local wiki,
1713                         // so we treat it like a local interwiki.
1714                         $interwiki = self::getInterwikiLookup()->fetch( $this->mInterwiki );
1715                         if ( $interwiki && !$interwiki->isLocal() ) {
1716                                 return '#' . Sanitizer::escapeIdForExternalInterwiki( $this->mFragment );
1717                         }
1718                 }
1719
1720                 return '#' . Sanitizer::escapeIdForLink( $this->mFragment );
1721         }
1722
1723         /**
1724          * Set the fragment for this title. Removes the first character from the
1725          * specified fragment before setting, so it assumes you're passing it with
1726          * an initial "#".
1727          *
1728          * Deprecated for public use, use Title::makeTitle() with fragment parameter,
1729          * or Title::createFragmentTarget().
1730          * Still in active use privately.
1731          *
1732          * @private
1733          * @param string $fragment Text
1734          */
1735         public function setFragment( $fragment ) {
1736                 $this->mFragment = strtr( substr( $fragment, 1 ), '_', ' ' );
1737         }
1738
1739         /**
1740          * Creates a new Title for a different fragment of the same page.
1741          *
1742          * @since 1.27
1743          * @param string $fragment
1744          * @return Title
1745          */
1746         public function createFragmentTarget( $fragment ) {
1747                 return self::makeTitle(
1748                         $this->mNamespace,
1749                         $this->getText(),
1750                         $fragment,
1751                         $this->mInterwiki
1752                 );
1753         }
1754
1755         /**
1756          * Prefix some arbitrary text with the namespace or interwiki prefix
1757          * of this object
1758          *
1759          * @param string $name The text
1760          * @return string The prefixed text
1761          */
1762         private function prefix( $name ) {
1763                 $p = '';
1764                 if ( $this->isExternal() ) {
1765                         $p = $this->mInterwiki . ':';
1766                 }
1767
1768                 if ( $this->mNamespace != 0 ) {
1769                         $nsText = $this->getNsText();
1770
1771                         if ( $nsText === false ) {
1772                                 // See T165149. Awkward, but better than erroneously linking to the main namespace.
1773                                 $nsText = MediaWikiServices::getInstance()->getContentLanguage()->
1774                                         getNsText( NS_SPECIAL ) . ":Badtitle/NS{$this->mNamespace}";
1775                         }
1776
1777                         $p .= $nsText . ':';
1778                 }
1779                 return $p . $name;
1780         }
1781
1782         /**
1783          * Get the prefixed database key form
1784          *
1785          * @return string The prefixed title, with underscores and
1786          *  any interwiki and namespace prefixes
1787          */
1788         public function getPrefixedDBkey() {
1789                 $s = $this->prefix( $this->mDbkeyform );
1790                 $s = strtr( $s, ' ', '_' );
1791                 return $s;
1792         }
1793
1794         /**
1795          * Get the prefixed title with spaces.
1796          * This is the form usually used for display
1797          *
1798          * @return string The prefixed title, with spaces
1799          */
1800         public function getPrefixedText() {
1801                 if ( $this->prefixedText === null ) {
1802                         $s = $this->prefix( $this->mTextform );
1803                         $s = strtr( $s, '_', ' ' );
1804                         $this->prefixedText = $s;
1805                 }
1806                 return $this->prefixedText;
1807         }
1808
1809         /**
1810          * Return a string representation of this title
1811          *
1812          * @return string Representation of this title
1813          */
1814         public function __toString() {
1815                 return $this->getPrefixedText();
1816         }
1817
1818         /**
1819          * Get the prefixed title with spaces, plus any fragment
1820          * (part beginning with '#')
1821          *
1822          * @return string The prefixed title, with spaces and the fragment, including '#'
1823          */
1824         public function getFullText() {
1825                 $text = $this->getPrefixedText();
1826                 if ( $this->hasFragment() ) {
1827                         $text .= '#' . $this->mFragment;
1828                 }
1829                 return $text;
1830         }
1831
1832         /**
1833          * Get the root page name text without a namespace, i.e. the leftmost part before any slashes
1834          *
1835          * @note the return value may contain trailing whitespace and is thus
1836          * not safe for use with makeTitle or TitleValue.
1837          *
1838          * @par Example:
1839          * @code
1840          * Title::newFromText('User:Foo/Bar/Baz')->getRootText();
1841          * # returns: 'Foo'
1842          * @endcode
1843          *
1844          * @return string Root name
1845          * @since 1.20
1846          */
1847         public function getRootText() {
1848                 if (
1849                         !MediaWikiServices::getInstance()->getNamespaceInfo()->
1850                                 hasSubpages( $this->mNamespace )
1851                         || strtok( $this->getText(), '/' ) === false
1852                 ) {
1853                         return $this->getText();
1854                 }
1855
1856                 return strtok( $this->getText(), '/' );
1857         }
1858
1859         /**
1860          * Get the root page name title, i.e. the leftmost part before any slashes
1861          *
1862          * @par Example:
1863          * @code
1864          * Title::newFromText('User:Foo/Bar/Baz')->getRootTitle();
1865          * # returns: Title{User:Foo}
1866          * @endcode
1867          *
1868          * @return Title Root title
1869          * @since 1.20
1870          */
1871         public function getRootTitle() {
1872                 $title = self::makeTitleSafe( $this->mNamespace, $this->getRootText() );
1873                 Assert::postcondition(
1874                         $title !== null,
1875                         'makeTitleSafe() should always return a Title for the text returned by getRootText().'
1876                 );
1877                 return $title;
1878         }
1879
1880         /**
1881          * Get the base page name without a namespace, i.e. the part before the subpage name
1882          *
1883          * @note the return value may contain trailing whitespace and is thus
1884          * not safe for use with makeTitle or TitleValue.
1885          *
1886          * @par Example:
1887          * @code
1888          * Title::newFromText('User:Foo/Bar/Baz')->getBaseText();
1889          * # returns: 'Foo/Bar'
1890          * @endcode
1891          *
1892          * @return string Base name
1893          */
1894         public function getBaseText() {
1895                 $text = $this->getText();
1896                 if (
1897                         !MediaWikiServices::getInstance()->getNamespaceInfo()->
1898                                 hasSubpages( $this->mNamespace )
1899                 ) {
1900                         return $text;
1901                 }
1902
1903                 $lastSlashPos = strrpos( $text, '/' );
1904                 // Don't discard the real title if there's no subpage involved
1905                 if ( $lastSlashPos === false ) {
1906                         return $text;
1907                 }
1908
1909                 return substr( $text, 0, $lastSlashPos );
1910         }
1911
1912         /**
1913          * Get the base page name title, i.e. the part before the subpage name.
1914          *
1915          * @par Example:
1916          * @code
1917          * Title::newFromText('User:Foo/Bar/Baz')->getBaseTitle();
1918          * # returns: Title{User:Foo/Bar}
1919          * @endcode
1920          *
1921          * @return Title Base title
1922          * @since 1.20
1923          */
1924         public function getBaseTitle() {
1925                 $title = self::makeTitleSafe( $this->mNamespace, $this->getBaseText() );
1926                 Assert::postcondition(
1927                         $title !== null,
1928                         'makeTitleSafe() should always return a Title for the text returned by getBaseText().'
1929                 );
1930                 return $title;
1931         }
1932
1933         /**
1934          * Get the lowest-level subpage name, i.e. the rightmost part after any slashes
1935          *
1936          * @par Example:
1937          * @code
1938          * Title::newFromText('User:Foo/Bar/Baz')->getSubpageText();
1939          * # returns: "Baz"
1940          * @endcode
1941          *
1942          * @return string Subpage name
1943          */
1944         public function getSubpageText() {
1945                 if (
1946                         !MediaWikiServices::getInstance()->getNamespaceInfo()->
1947                                 hasSubpages( $this->mNamespace )
1948                 ) {
1949                         return $this->mTextform;
1950                 }
1951                 $parts = explode( '/', $this->mTextform );
1952                 return $parts[count( $parts ) - 1];
1953         }
1954
1955         /**
1956          * Get the title for a subpage of the current page
1957          *
1958          * @par Example:
1959          * @code
1960          * Title::newFromText('User:Foo/Bar/Baz')->getSubpage("Asdf");
1961          * # returns: Title{User:Foo/Bar/Baz/Asdf}
1962          * @endcode
1963          *
1964          * @param string $text The subpage name to add to the title
1965          * @return Title|null Subpage title, or null on an error
1966          * @since 1.20
1967          */
1968         public function getSubpage( $text ) {
1969                 return self::makeTitleSafe(
1970                         $this->mNamespace,
1971                         $this->getText() . '/' . $text,
1972                         '',
1973                         $this->mInterwiki
1974                 );
1975         }
1976
1977         /**
1978          * Get a URL-encoded form of the subpage text
1979          *
1980          * @return string URL-encoded subpage name
1981          */
1982         public function getSubpageUrlForm() {
1983                 $text = $this->getSubpageText();
1984                 $text = wfUrlencode( strtr( $text, ' ', '_' ) );
1985                 return $text;
1986         }
1987
1988         /**
1989          * Get a URL-encoded title (not an actual URL) including interwiki
1990          *
1991          * @return string The URL-encoded form
1992          */
1993         public function getPrefixedURL() {
1994                 $s = $this->prefix( $this->mDbkeyform );
1995                 $s = wfUrlencode( strtr( $s, ' ', '_' ) );
1996                 return $s;
1997         }
1998
1999         /**
2000          * Helper to fix up the get{Canonical,Full,Link,Local,Internal}URL args
2001          * get{Canonical,Full,Link,Local,Internal}URL methods accepted an optional
2002          * second argument named variant. This was deprecated in favor
2003          * of passing an array of option with a "variant" key
2004          * Once $query2 is removed for good, this helper can be dropped
2005          * and the wfArrayToCgi moved to getLocalURL();
2006          *
2007          * @since 1.19 (r105919)
2008          * @param array|string $query
2009          * @param string|string[]|bool $query2
2010          * @return string
2011          */
2012         private static function fixUrlQueryArgs( $query, $query2 = false ) {
2013                 if ( $query2 !== false ) {
2014                         wfDeprecated( "Title::get{Canonical,Full,Link,Local,Internal}URL " .
2015                                 "method called with a second parameter is deprecated. Add your " .
2016                                 "parameter to an array passed as the first parameter.", "1.19" );
2017                 }
2018                 if ( is_array( $query ) ) {
2019                         $query = wfArrayToCgi( $query );
2020                 }
2021                 if ( $query2 ) {
2022                         if ( is_string( $query2 ) ) {
2023                                 // $query2 is a string, we will consider this to be
2024                                 // a deprecated $variant argument and add it to the query
2025                                 $query2 = wfArrayToCgi( [ 'variant' => $query2 ] );
2026                         } else {
2027                                 $query2 = wfArrayToCgi( $query2 );
2028                         }
2029                         // If we have $query content add a & to it first
2030                         if ( $query ) {
2031                                 $query .= '&';
2032                         }
2033                         // Now append the queries together
2034                         $query .= $query2;
2035                 }
2036                 return $query;
2037         }
2038
2039         /**
2040          * Get a real URL referring to this title, with interwiki link and
2041          * fragment
2042          *
2043          * @see self::getLocalURL for the arguments.
2044          * @see wfExpandUrl
2045          * @param string|string[] $query
2046          * @param string|string[]|bool $query2
2047          * @param string|int|null $proto Protocol type to use in URL
2048          * @return string The URL
2049          */
2050         public function getFullURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
2051                 $query = self::fixUrlQueryArgs( $query, $query2 );
2052
2053                 # Hand off all the decisions on urls to getLocalURL
2054                 $url = $this->getLocalURL( $query );
2055
2056                 # Expand the url to make it a full url. Note that getLocalURL has the
2057                 # potential to output full urls for a variety of reasons, so we use
2058                 # wfExpandUrl instead of simply prepending $wgServer
2059                 $url = wfExpandUrl( $url, $proto );
2060
2061                 # Finally, add the fragment.
2062                 $url .= $this->getFragmentForURL();
2063                 // Avoid PHP 7.1 warning from passing $this by reference
2064                 $titleRef = $this;
2065                 Hooks::run( 'GetFullURL', [ &$titleRef, &$url, $query ] );
2066                 return $url;
2067         }
2068
2069         /**
2070          * Get a url appropriate for making redirects based on an untrusted url arg
2071          *
2072          * This is basically the same as getFullUrl(), but in the case of external
2073          * interwikis, we send the user to a landing page, to prevent possible
2074          * phishing attacks and the like.
2075          *
2076          * @note Uses current protocol by default, since technically relative urls
2077          *   aren't allowed in redirects per HTTP spec, so this is not suitable for
2078          *   places where the url gets cached, as might pollute between
2079          *   https and non-https users.
2080          * @see self::getLocalURL for the arguments.
2081          * @param array|string $query
2082          * @param string $proto Protocol type to use in URL
2083          * @return string A url suitable to use in an HTTP location header.
2084          */
2085         public function getFullUrlForRedirect( $query = '', $proto = PROTO_CURRENT ) {
2086                 $target = $this;
2087                 if ( $this->isExternal() ) {
2088                         $target = SpecialPage::getTitleFor(
2089                                 'GoToInterwiki',
2090                                 $this->getPrefixedDBkey()
2091                         );
2092                 }
2093                 return $target->getFullURL( $query, false, $proto );
2094         }
2095
2096         /**
2097          * Get a URL with no fragment or server name (relative URL) from a Title object.
2098          * If this page is generated with action=render, however,
2099          * $wgServer is prepended to make an absolute URL.
2100          *
2101          * @see self::getFullURL to always get an absolute URL.
2102          * @see self::getLinkURL to always get a URL that's the simplest URL that will be
2103          *  valid to link, locally, to the current Title.
2104          * @see self::newFromText to produce a Title object.
2105          *
2106          * @param string|string[] $query An optional query string,
2107          *   not used for interwiki links. Can be specified as an associative array as well,
2108          *   e.g., [ 'action' => 'edit' ] (keys and values will be URL-escaped).
2109          *   Some query patterns will trigger various shorturl path replacements.
2110          * @param string|string[]|bool $query2 An optional secondary query array. This one MUST
2111          *   be an array. If a string is passed it will be interpreted as a deprecated
2112          *   variant argument and urlencoded into a variant= argument.
2113          *   This second query argument will be added to the $query
2114          *   The second parameter is deprecated since 1.19. Pass it as a key,value
2115          *   pair in the first parameter array instead.
2116          *
2117          * @return string String of the URL.
2118          */
2119         public function getLocalURL( $query = '', $query2 = false ) {
2120                 global $wgArticlePath, $wgScript, $wgServer, $wgRequest;
2121
2122                 $query = self::fixUrlQueryArgs( $query, $query2 );
2123
2124                 $interwiki = self::getInterwikiLookup()->fetch( $this->mInterwiki );
2125                 if ( $interwiki ) {
2126                         $namespace = $this->getNsText();
2127                         if ( $namespace != '' ) {
2128                                 # Can this actually happen? Interwikis shouldn't be parsed.
2129                                 # Yes! It can in interwiki transclusion. But... it probably shouldn't.
2130                                 $namespace .= ':';
2131                         }
2132                         $url = $interwiki->getURL( $namespace . $this->mDbkeyform );
2133                         $url = wfAppendQuery( $url, $query );
2134                 } else {
2135                         $dbkey = wfUrlencode( $this->getPrefixedDBkey() );
2136                         if ( $query == '' ) {
2137                                 $url = str_replace( '$1', $dbkey, $wgArticlePath );
2138                                 // Avoid PHP 7.1 warning from passing $this by reference
2139                                 $titleRef = $this;
2140                                 Hooks::run( 'GetLocalURL::Article', [ &$titleRef, &$url ] );
2141                         } else {
2142                                 global $wgVariantArticlePath, $wgActionPaths;
2143                                 $url = false;
2144                                 $matches = [];
2145
2146                                 if ( !empty( $wgActionPaths )
2147                                         && preg_match( '/^(.*&|)action=([^&]*)(&(.*)|)$/', $query, $matches )
2148                                 ) {
2149                                         $action = urldecode( $matches[2] );
2150                                         if ( isset( $wgActionPaths[$action] ) ) {
2151                                                 $query = $matches[1];
2152                                                 if ( isset( $matches[4] ) ) {
2153                                                         $query .= $matches[4];
2154                                                 }
2155                                                 $url = str_replace( '$1', $dbkey, $wgActionPaths[$action] );
2156                                                 if ( $query != '' ) {
2157                                                         $url = wfAppendQuery( $url, $query );
2158                                                 }
2159                                         }
2160                                 }
2161
2162                                 if ( $url === false
2163                                         && $wgVariantArticlePath
2164                                         && preg_match( '/^variant=([^&]*)$/', $query, $matches )
2165                                         && $this->getPageLanguage()->equals(
2166                                                 MediaWikiServices::getInstance()->getContentLanguage() )
2167                                         && $this->getPageLanguage()->hasVariants()
2168                                 ) {
2169                                         $variant = urldecode( $matches[1] );
2170                                         if ( $this->getPageLanguage()->hasVariant( $variant ) ) {
2171                                                 // Only do the variant replacement if the given variant is a valid
2172                                                 // variant for the page's language.
2173                                                 $url = str_replace( '$2', urlencode( $variant ), $wgVariantArticlePath );
2174                                                 $url = str_replace( '$1', $dbkey, $url );
2175                                         }
2176                                 }
2177
2178                                 if ( $url === false ) {
2179                                         if ( $query == '-' ) {
2180                                                 $query = '';
2181                                         }
2182                                         $url = "{$wgScript}?title={$dbkey}&{$query}";
2183                                 }
2184                         }
2185                         // Avoid PHP 7.1 warning from passing $this by reference
2186                         $titleRef = $this;
2187                         Hooks::run( 'GetLocalURL::Internal', [ &$titleRef, &$url, $query ] );
2188
2189                         // @todo FIXME: This causes breakage in various places when we
2190                         // actually expected a local URL and end up with dupe prefixes.
2191                         if ( $wgRequest->getVal( 'action' ) == 'render' ) {
2192                                 $url = $wgServer . $url;
2193                         }
2194                 }
2195                 // Avoid PHP 7.1 warning from passing $this by reference
2196                 $titleRef = $this;
2197                 Hooks::run( 'GetLocalURL', [ &$titleRef, &$url, $query ] );
2198                 return $url;
2199         }
2200
2201         /**
2202          * Get a URL that's the simplest URL that will be valid to link, locally,
2203          * to the current Title.  It includes the fragment, but does not include
2204          * the server unless action=render is used (or the link is external).  If
2205          * there's a fragment but the prefixed text is empty, we just return a link
2206          * to the fragment.
2207          *
2208          * The result obviously should not be URL-escaped, but does need to be
2209          * HTML-escaped if it's being output in HTML.
2210          *
2211          * @param string|string[] $query
2212          * @param bool $query2
2213          * @param string|int|bool $proto A PROTO_* constant on how the URL should be expanded,
2214          *                               or false (default) for no expansion
2215          * @see self::getLocalURL for the arguments.
2216          * @return string The URL
2217          */
2218         public function getLinkURL( $query = '', $query2 = false, $proto = false ) {
2219                 if ( $this->isExternal() || $proto !== false ) {
2220                         $ret = $this->getFullURL( $query, $query2, $proto );
2221                 } elseif ( $this->getPrefixedText() === '' && $this->hasFragment() ) {
2222                         $ret = $this->getFragmentForURL();
2223                 } else {
2224                         $ret = $this->getLocalURL( $query, $query2 ) . $this->getFragmentForURL();
2225                 }
2226                 return $ret;
2227         }
2228
2229         /**
2230          * Get the URL form for an internal link.
2231          * - Used in various CDN-related code, in case we have a different
2232          * internal hostname for the server from the exposed one.
2233          *
2234          * This uses $wgInternalServer to qualify the path, or $wgServer
2235          * if $wgInternalServer is not set. If the server variable used is
2236          * protocol-relative, the URL will be expanded to http://
2237          *
2238          * @see self::getLocalURL for the arguments.
2239          * @param string|string[] $query
2240          * @param string|bool $query2 Deprecated
2241          * @return string The URL
2242          */
2243         public function getInternalURL( $query = '', $query2 = false ) {
2244                 global $wgInternalServer, $wgServer;
2245                 $query = self::fixUrlQueryArgs( $query, $query2 );
2246                 $server = $wgInternalServer !== false ? $wgInternalServer : $wgServer;
2247                 $url = wfExpandUrl( $server . $this->getLocalURL( $query ), PROTO_HTTP );
2248                 // Avoid PHP 7.1 warning from passing $this by reference
2249                 $titleRef = $this;
2250                 Hooks::run( 'GetInternalURL', [ &$titleRef, &$url, $query ] );
2251                 return $url;
2252         }
2253
2254         /**
2255          * Get the URL for a canonical link, for use in things like IRC and
2256          * e-mail notifications. Uses $wgCanonicalServer and the
2257          * GetCanonicalURL hook.
2258          *
2259          * NOTE: Unlike getInternalURL(), the canonical URL includes the fragment
2260          *
2261          * @see self::getLocalURL for the arguments.
2262          * @param string|string[] $query
2263          * @param string|bool $query2 Deprecated
2264          * @return string The URL
2265          * @since 1.18
2266          */
2267         public function getCanonicalURL( $query = '', $query2 = false ) {
2268                 $query = self::fixUrlQueryArgs( $query, $query2 );
2269                 $url = wfExpandUrl( $this->getLocalURL( $query ) . $this->getFragmentForURL(), PROTO_CANONICAL );
2270                 // Avoid PHP 7.1 warning from passing $this by reference
2271                 $titleRef = $this;
2272                 Hooks::run( 'GetCanonicalURL', [ &$titleRef, &$url, $query ] );
2273                 return $url;
2274         }
2275
2276         /**
2277          * Get the edit URL for this Title
2278          *
2279          * @return string The URL, or a null string if this is an interwiki link
2280          */
2281         public function getEditURL() {
2282                 if ( $this->isExternal() ) {
2283                         return '';
2284                 }
2285                 $s = $this->getLocalURL( 'action=edit' );
2286
2287                 return $s;
2288         }
2289
2290         /**
2291          * Can $user perform $action on this page?
2292          * This skips potentially expensive cascading permission checks
2293          * as well as avoids expensive error formatting
2294          *
2295          * Suitable for use for nonessential UI controls in common cases, but
2296          * _not_ for functional access control.
2297          *
2298          * May provide false positives, but should never provide a false negative.
2299          *
2300          * @param string $action Action that permission needs to be checked for
2301          * @param User|null $user User to check (since 1.19); $wgUser will be used if not provided.
2302          *
2303          * @return bool
2304          * @throws Exception
2305          *
2306          * @deprecated since 1.33,
2307          * use MediaWikiServices::getInstance()->getPermissionManager()->quickUserCan(..) instead
2308          *
2309          */
2310         public function quickUserCan( $action, $user = null ) {
2311                 return $this->userCan( $action, $user, false );
2312         }
2313
2314         /**
2315          * Can $user perform $action on this page?
2316          *
2317          * @param string $action Action that permission needs to be checked for
2318          * @param User|null $user User to check (since 1.19); $wgUser will be used if not
2319          *   provided.
2320          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2321          *
2322          * @return bool
2323          * @throws Exception
2324          *
2325          * @deprecated since 1.33,
2326          * use MediaWikiServices::getInstance()->getPermissionManager()->userCan(..) instead
2327          *
2328          */
2329         public function userCan( $action, $user = null, $rigor = PermissionManager::RIGOR_SECURE ) {
2330                 if ( !$user instanceof User ) {
2331                         global $wgUser;
2332                         $user = $wgUser;
2333                 }
2334
2335                 // TODO: this is for b/c, eventually will be removed
2336                 if ( $rigor === true ) {
2337                         $rigor = PermissionManager::RIGOR_SECURE; // b/c
2338                 } elseif ( $rigor === false ) {
2339                         $rigor = PermissionManager::RIGOR_QUICK; // b/c
2340                 }
2341
2342                 return MediaWikiServices::getInstance()->getPermissionManager()
2343                         ->userCan( $action, $user, $this, $rigor );
2344         }
2345
2346         /**
2347          * Can $user perform $action on this page?
2348          *
2349          * @todo FIXME: This *does not* check throttles (User::pingLimiter()).
2350          *
2351          * @param string $action Action that permission needs to be checked for
2352          * @param User $user User to check
2353          * @param string $rigor One of (quick,full,secure)
2354          *   - quick  : does cheap permission checks from replica DBs (usable for GUI creation)
2355          *   - full   : does cheap and expensive checks possibly from a replica DB
2356          *   - secure : does cheap and expensive checks, using the master as needed
2357          * @param array $ignoreErrors Array of Strings Set this to a list of message keys
2358          *   whose corresponding errors may be ignored.
2359          *
2360          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
2361          * @throws Exception
2362          *
2363          * @deprecated since 1.33,
2364          * use MediaWikiServices::getInstance()->getPermissionManager()->getPermissionErrors()
2365          *
2366          */
2367         public function getUserPermissionsErrors(
2368                 $action, $user, $rigor = PermissionManager::RIGOR_SECURE, $ignoreErrors = []
2369         ) {
2370                 // TODO: this is for b/c, eventually will be removed
2371                 if ( $rigor === true ) {
2372                         $rigor = PermissionManager::RIGOR_SECURE; // b/c
2373                 } elseif ( $rigor === false ) {
2374                         $rigor = PermissionManager::RIGOR_QUICK; // b/c
2375                 }
2376
2377                 return MediaWikiServices::getInstance()->getPermissionManager()
2378                         ->getPermissionErrors( $action, $user, $this, $rigor, $ignoreErrors );
2379         }
2380
2381         /**
2382          * Get a filtered list of all restriction types supported by this wiki.
2383          * @param bool $exists True to get all restriction types that apply to
2384          * titles that do exist, False for all restriction types that apply to
2385          * titles that do not exist
2386          * @return array
2387          */
2388         public static function getFilteredRestrictionTypes( $exists = true ) {
2389                 global $wgRestrictionTypes;
2390                 $types = $wgRestrictionTypes;
2391                 if ( $exists ) {
2392                         # Remove the create restriction for existing titles
2393                         $types = array_diff( $types, [ 'create' ] );
2394                 } else {
2395                         # Only the create and upload restrictions apply to non-existing titles
2396                         $types = array_intersect( $types, [ 'create', 'upload' ] );
2397                 }
2398                 return $types;
2399         }
2400
2401         /**
2402          * Returns restriction types for the current Title
2403          *
2404          * @return array Applicable restriction types
2405          */
2406         public function getRestrictionTypes() {
2407                 if ( $this->isSpecialPage() ) {
2408                         return [];
2409                 }
2410
2411                 $types = self::getFilteredRestrictionTypes( $this->exists() );
2412
2413                 if ( $this->mNamespace != NS_FILE ) {
2414                         # Remove the upload restriction for non-file titles
2415                         $types = array_diff( $types, [ 'upload' ] );
2416                 }
2417
2418                 Hooks::run( 'TitleGetRestrictionTypes', [ $this, &$types ] );
2419
2420                 wfDebug( __METHOD__ . ': applicable restrictions to [[' .
2421                         $this->getPrefixedText() . ']] are {' . implode( ',', $types ) . "}\n" );
2422
2423                 return $types;
2424         }
2425
2426         /**
2427          * Is this title subject to title protection?
2428          * Title protection is the one applied against creation of such title.
2429          *
2430          * @return array|bool An associative array representing any existent title
2431          *   protection, or false if there's none.
2432          */
2433         public function getTitleProtection() {
2434                 $protection = $this->getTitleProtectionInternal();
2435                 if ( $protection ) {
2436                         if ( $protection['permission'] == 'sysop' ) {
2437                                 $protection['permission'] = 'editprotected'; // B/C
2438                         }
2439                         if ( $protection['permission'] == 'autoconfirmed' ) {
2440                                 $protection['permission'] = 'editsemiprotected'; // B/C
2441                         }
2442                 }
2443                 return $protection;
2444         }
2445
2446         /**
2447          * Fetch title protection settings
2448          *
2449          * To work correctly, $this->loadRestrictions() needs to have access to the
2450          * actual protections in the database without munging 'sysop' =>
2451          * 'editprotected' and 'autoconfirmed' => 'editsemiprotected'. Other
2452          * callers probably want $this->getTitleProtection() instead.
2453          *
2454          * @return array|bool
2455          */
2456         protected function getTitleProtectionInternal() {
2457                 // Can't protect pages in special namespaces
2458                 if ( $this->mNamespace < 0 ) {
2459                         return false;
2460                 }
2461
2462                 // Can't protect pages that exist.
2463                 if ( $this->exists() ) {
2464                         return false;
2465                 }
2466
2467                 if ( $this->mTitleProtection === null ) {
2468                         $dbr = wfGetDB( DB_REPLICA );
2469                         $commentStore = CommentStore::getStore();
2470                         $commentQuery = $commentStore->getJoin( 'pt_reason' );
2471                         $res = $dbr->select(
2472                                 [ 'protected_titles' ] + $commentQuery['tables'],
2473                                 [
2474                                         'user' => 'pt_user',
2475                                         'expiry' => 'pt_expiry',
2476                                         'permission' => 'pt_create_perm'
2477                                 ] + $commentQuery['fields'],
2478                                 [ 'pt_namespace' => $this->mNamespace, 'pt_title' => $this->mDbkeyform ],
2479                                 __METHOD__,
2480                                 [],
2481                                 $commentQuery['joins']
2482                         );
2483
2484                         // fetchRow returns false if there are no rows.
2485                         $row = $dbr->fetchRow( $res );
2486                         if ( $row ) {
2487                                 $this->mTitleProtection = [
2488                                         'user' => $row['user'],
2489                                         'expiry' => $dbr->decodeExpiry( $row['expiry'] ),
2490                                         'permission' => $row['permission'],
2491                                         'reason' => $commentStore->getComment( 'pt_reason', $row )->text,
2492                                 ];
2493                         } else {
2494                                 $this->mTitleProtection = false;
2495                         }
2496                 }
2497                 return $this->mTitleProtection;
2498         }
2499
2500         /**
2501          * Remove any title protection due to page existing
2502          */
2503         public function deleteTitleProtection() {
2504                 $dbw = wfGetDB( DB_MASTER );
2505
2506                 $dbw->delete(
2507                         'protected_titles',
2508                         [ 'pt_namespace' => $this->mNamespace, 'pt_title' => $this->mDbkeyform ],
2509                         __METHOD__
2510                 );
2511                 $this->mTitleProtection = false;
2512         }
2513
2514         /**
2515          * Is this page "semi-protected" - the *only* protection levels are listed
2516          * in $wgSemiprotectedRestrictionLevels?
2517          *
2518          * @param string $action Action to check (default: edit)
2519          * @return bool
2520          */
2521         public function isSemiProtected( $action = 'edit' ) {
2522                 global $wgSemiprotectedRestrictionLevels;
2523
2524                 $restrictions = $this->getRestrictions( $action );
2525                 $semi = $wgSemiprotectedRestrictionLevels;
2526                 if ( !$restrictions || !$semi ) {
2527                         // Not protected, or all protection is full protection
2528                         return false;
2529                 }
2530
2531                 // Remap autoconfirmed to editsemiprotected for BC
2532                 foreach ( array_keys( $semi, 'autoconfirmed' ) as $key ) {
2533                         $semi[$key] = 'editsemiprotected';
2534                 }
2535                 foreach ( array_keys( $restrictions, 'autoconfirmed' ) as $key ) {
2536                         $restrictions[$key] = 'editsemiprotected';
2537                 }
2538
2539                 return !array_diff( $restrictions, $semi );
2540         }
2541
2542         /**
2543          * Does the title correspond to a protected article?
2544          *
2545          * @param string $action The action the page is protected from,
2546          * by default checks all actions.
2547          * @return bool
2548          */
2549         public function isProtected( $action = '' ) {
2550                 global $wgRestrictionLevels;
2551
2552                 $restrictionTypes = $this->getRestrictionTypes();
2553
2554                 # Special pages have inherent protection
2555                 if ( $this->isSpecialPage() ) {
2556                         return true;
2557                 }
2558
2559                 # Check regular protection levels
2560                 foreach ( $restrictionTypes as $type ) {
2561                         if ( $action == $type || $action == '' ) {
2562                                 $r = $this->getRestrictions( $type );
2563                                 foreach ( $wgRestrictionLevels as $level ) {
2564                                         if ( in_array( $level, $r ) && $level != '' ) {
2565                                                 return true;
2566                                         }
2567                                 }
2568                         }
2569                 }
2570
2571                 return false;
2572         }
2573
2574         /**
2575          * Determines if $user is unable to edit this page because it has been protected
2576          * by $wgNamespaceProtection.
2577          *
2578          * @deprecated since 1.34 Don't use this function in new code.
2579          * @param User $user User object to check permissions
2580          * @return bool
2581          */
2582         public function isNamespaceProtected( User $user ) {
2583                 global $wgNamespaceProtection;
2584
2585                 if ( isset( $wgNamespaceProtection[$this->mNamespace] ) ) {
2586                         $permissionManager = MediaWikiServices::getInstance()->getPermissionManager();
2587                         foreach ( (array)$wgNamespaceProtection[$this->mNamespace] as $right ) {
2588                                 if ( !$permissionManager->userHasRight( $user, $right ) ) {
2589                                         return true;
2590                                 }
2591                         }
2592                 }
2593                 return false;
2594         }
2595
2596         /**
2597          * Cascading protection: Return true if cascading restrictions apply to this page, false if not.
2598          *
2599          * @return bool If the page is subject to cascading restrictions.
2600          */
2601         public function isCascadeProtected() {
2602                 list( $sources, /* $restrictions */ ) = $this->getCascadeProtectionSources( false );
2603                 return ( $sources > 0 );
2604         }
2605
2606         /**
2607          * Determines whether cascading protection sources have already been loaded from
2608          * the database.
2609          *
2610          * @param bool $getPages True to check if the pages are loaded, or false to check
2611          * if the status is loaded.
2612          * @return bool Whether or not the specified information has been loaded
2613          * @since 1.23
2614          */
2615         public function areCascadeProtectionSourcesLoaded( $getPages = true ) {
2616                 return $getPages ? $this->mCascadeSources !== null : $this->mHasCascadingRestrictions !== null;
2617         }
2618
2619         /**
2620          * Cascading protection: Get the source of any cascading restrictions on this page.
2621          *
2622          * @param bool $getPages Whether or not to retrieve the actual pages
2623          *        that the restrictions have come from and the actual restrictions
2624          *        themselves.
2625          * @return array Two elements: First is an array of Title objects of the
2626          *        pages from which cascading restrictions have come, false for
2627          *        none, or true if such restrictions exist but $getPages was not
2628          *        set. Second is an array like that returned by
2629          *        Title::getAllRestrictions(), or an empty array if $getPages is
2630          *        false.
2631          */
2632         public function getCascadeProtectionSources( $getPages = true ) {
2633                 $pagerestrictions = [];
2634
2635                 if ( $this->mCascadeSources !== null && $getPages ) {
2636                         return [ $this->mCascadeSources, $this->mCascadingRestrictions ];
2637                 } elseif ( $this->mHasCascadingRestrictions !== null && !$getPages ) {
2638                         return [ $this->mHasCascadingRestrictions, $pagerestrictions ];
2639                 }
2640
2641                 $dbr = wfGetDB( DB_REPLICA );
2642
2643                 if ( $this->mNamespace == NS_FILE ) {
2644                         $tables = [ 'imagelinks', 'page_restrictions' ];
2645                         $where_clauses = [
2646                                 'il_to' => $this->mDbkeyform,
2647                                 'il_from=pr_page',
2648                                 'pr_cascade' => 1
2649                         ];
2650                 } else {
2651                         $tables = [ 'templatelinks', 'page_restrictions' ];
2652                         $where_clauses = [
2653                                 'tl_namespace' => $this->mNamespace,
2654                                 'tl_title' => $this->mDbkeyform,
2655                                 'tl_from=pr_page',
2656                                 'pr_cascade' => 1
2657                         ];
2658                 }
2659
2660                 if ( $getPages ) {
2661                         $cols = [ 'pr_page', 'page_namespace', 'page_title',
2662                                 'pr_expiry', 'pr_type', 'pr_level' ];
2663                         $where_clauses[] = 'page_id=pr_page';
2664                         $tables[] = 'page';
2665                 } else {
2666                         $cols = [ 'pr_expiry' ];
2667                 }
2668
2669                 $res = $dbr->select( $tables, $cols, $where_clauses, __METHOD__ );
2670
2671                 $sources = $getPages ? [] : false;
2672                 $now = wfTimestampNow();
2673
2674                 foreach ( $res as $row ) {
2675                         $expiry = $dbr->decodeExpiry( $row->pr_expiry );
2676                         if ( $expiry > $now ) {
2677                                 if ( $getPages ) {
2678                                         $page_id = $row->pr_page;
2679                                         $page_ns = $row->page_namespace;
2680                                         $page_title = $row->page_title;
2681                                         $sources[$page_id] = self::makeTitle( $page_ns, $page_title );
2682                                         # Add groups needed for each restriction type if its not already there
2683                                         # Make sure this restriction type still exists
2684
2685                                         if ( !isset( $pagerestrictions[$row->pr_type] ) ) {
2686                                                 $pagerestrictions[$row->pr_type] = [];
2687                                         }
2688
2689                                         if (
2690                                                 isset( $pagerestrictions[$row->pr_type] )
2691                                                 && !in_array( $row->pr_level, $pagerestrictions[$row->pr_type] )
2692                                         ) {
2693                                                 $pagerestrictions[$row->pr_type][] = $row->pr_level;
2694                                         }
2695                                 } else {
2696                                         $sources = true;
2697                                 }
2698                         }
2699                 }
2700
2701                 if ( $getPages ) {
2702                         $this->mCascadeSources = $sources;
2703                         $this->mCascadingRestrictions = $pagerestrictions;
2704                 } else {
2705                         $this->mHasCascadingRestrictions = $sources;
2706                 }
2707
2708                 return [ $sources, $pagerestrictions ];
2709         }
2710
2711         /**
2712          * Accessor for mRestrictionsLoaded
2713          *
2714          * @return bool Whether or not the page's restrictions have already been
2715          * loaded from the database
2716          * @since 1.23
2717          */
2718         public function areRestrictionsLoaded() {
2719                 return $this->mRestrictionsLoaded;
2720         }
2721
2722         /**
2723          * Accessor/initialisation for mRestrictions
2724          *
2725          * @param string $action Action that permission needs to be checked for
2726          * @return array Restriction levels needed to take the action. All levels are
2727          *     required. Note that restriction levels are normally user rights, but 'sysop'
2728          *     and 'autoconfirmed' are also allowed for backwards compatibility. These should
2729          *     be mapped to 'editprotected' and 'editsemiprotected' respectively.
2730          */
2731         public function getRestrictions( $action ) {
2732                 if ( !$this->mRestrictionsLoaded ) {
2733                         $this->loadRestrictions();
2734                 }
2735                 return $this->mRestrictions[$action] ?? [];
2736         }
2737
2738         /**
2739          * Accessor/initialisation for mRestrictions
2740          *
2741          * @return array Keys are actions, values are arrays as returned by
2742          *     Title::getRestrictions()
2743          * @since 1.23
2744          */
2745         public function getAllRestrictions() {
2746                 if ( !$this->mRestrictionsLoaded ) {
2747                         $this->loadRestrictions();
2748                 }
2749                 return $this->mRestrictions;
2750         }
2751
2752         /**
2753          * Get the expiry time for the restriction against a given action
2754          *
2755          * @param string $action
2756          * @return string|bool 14-char timestamp, or 'infinity' if the page is protected forever
2757          *     or not protected at all, or false if the action is not recognised.
2758          */
2759         public function getRestrictionExpiry( $action ) {
2760                 if ( !$this->mRestrictionsLoaded ) {
2761                         $this->loadRestrictions();
2762                 }
2763                 return $this->mRestrictionsExpiry[$action] ?? false;
2764         }
2765
2766         /**
2767          * Returns cascading restrictions for the current article
2768          *
2769          * @return bool
2770          */
2771         function areRestrictionsCascading() {
2772                 if ( !$this->mRestrictionsLoaded ) {
2773                         $this->loadRestrictions();
2774                 }
2775
2776                 return $this->mCascadeRestriction;
2777         }
2778
2779         /**
2780          * Compiles list of active page restrictions from both page table (pre 1.10)
2781          * and page_restrictions table for this existing page.
2782          * Public for usage by LiquidThreads.
2783          *
2784          * @param array $rows Array of db result objects
2785          * @param string|null $oldFashionedRestrictions Comma-separated set of permission keys
2786          * indicating who can move or edit the page from the page table, (pre 1.10) rows.
2787          * Edit and move sections are separated by a colon
2788          * Example: "edit=autoconfirmed,sysop:move=sysop"
2789          */
2790         public function loadRestrictionsFromRows( $rows, $oldFashionedRestrictions = null ) {
2791                 // This function will only read rows from a table that we migrated away
2792                 // from before adding READ_LATEST support to loadRestrictions, so we
2793                 // don't need to support reading from DB_MASTER here.
2794                 $dbr = wfGetDB( DB_REPLICA );
2795
2796                 $restrictionTypes = $this->getRestrictionTypes();
2797
2798                 foreach ( $restrictionTypes as $type ) {
2799                         $this->mRestrictions[$type] = [];
2800                         $this->mRestrictionsExpiry[$type] = 'infinity';
2801                 }
2802
2803                 $this->mCascadeRestriction = false;
2804
2805                 # Backwards-compatibility: also load the restrictions from the page record (old format).
2806                 if ( $oldFashionedRestrictions !== null ) {
2807                         $this->mOldRestrictions = $oldFashionedRestrictions;
2808                 }
2809
2810                 if ( $this->mOldRestrictions === false ) {
2811                         $linkCache = MediaWikiServices::getInstance()->getLinkCache();
2812                         $linkCache->addLinkObj( $this ); # in case we already had an article ID
2813                         $this->mOldRestrictions = $linkCache->getGoodLinkFieldObj( $this, 'restrictions' );
2814                 }
2815
2816                 if ( $this->mOldRestrictions != '' ) {
2817                         foreach ( explode( ':', trim( $this->mOldRestrictions ) ) as $restrict ) {
2818                                 $temp = explode( '=', trim( $restrict ) );
2819                                 if ( count( $temp ) == 1 ) {
2820                                         // old old format should be treated as edit/move restriction
2821                                         $this->mRestrictions['edit'] = explode( ',', trim( $temp[0] ) );
2822                                         $this->mRestrictions['move'] = explode( ',', trim( $temp[0] ) );
2823                                 } else {
2824                                         $restriction = trim( $temp[1] );
2825                                         if ( $restriction != '' ) { // some old entries are empty
2826                                                 $this->mRestrictions[$temp[0]] = explode( ',', $restriction );
2827                                         }
2828                                 }
2829                         }
2830                 }
2831
2832                 if ( count( $rows ) ) {
2833                         # Current system - load second to make them override.
2834                         $now = wfTimestampNow();
2835
2836                         # Cycle through all the restrictions.
2837                         foreach ( $rows as $row ) {
2838                                 // Don't take care of restrictions types that aren't allowed
2839                                 if ( !in_array( $row->pr_type, $restrictionTypes ) ) {
2840                                         continue;
2841                                 }
2842
2843                                 $expiry = $dbr->decodeExpiry( $row->pr_expiry );
2844
2845                                 // Only apply the restrictions if they haven't expired!
2846                                 if ( !$expiry || $expiry > $now ) {
2847                                         $this->mRestrictionsExpiry[$row->pr_type] = $expiry;
2848                                         $this->mRestrictions[$row->pr_type] = explode( ',', trim( $row->pr_level ) );
2849
2850                                         $this->mCascadeRestriction |= $row->pr_cascade;
2851                                 }
2852                         }
2853                 }
2854
2855                 $this->mRestrictionsLoaded = true;
2856         }
2857
2858         /**
2859          * Load restrictions from the page_restrictions table
2860          *
2861          * @param string|null $oldFashionedRestrictions Comma-separated set of permission keys
2862          * indicating who can move or edit the page from the page table, (pre 1.10) rows.
2863          * Edit and move sections are separated by a colon
2864          * Example: "edit=autoconfirmed,sysop:move=sysop"
2865          * @param int $flags A bit field. If self::READ_LATEST is set, skip replicas and read
2866          *  from the master DB.
2867          */
2868         public function loadRestrictions( $oldFashionedRestrictions = null, $flags = 0 ) {
2869                 $readLatest = DBAccessObjectUtils::hasFlags( $flags, self::READ_LATEST );
2870                 if ( $this->mRestrictionsLoaded && !$readLatest ) {
2871                         return;
2872                 }
2873
2874                 // TODO: should probably pass $flags into getArticleID, but it seems hacky
2875                 // to mix READ_LATEST and GAID_FOR_UPDATE, even if they have the same value.
2876                 // Maybe deprecate GAID_FOR_UPDATE now that we implement IDBAccessObject?
2877                 $id = $this->getArticleID();
2878                 if ( $id ) {
2879                         $fname = __METHOD__;
2880                         $loadRestrictionsFromDb = function ( IDatabase $dbr ) use ( $fname, $id ) {
2881                                 return iterator_to_array(
2882                                         $dbr->select(
2883                                                 'page_restrictions',
2884                                                 [ 'pr_type', 'pr_expiry', 'pr_level', 'pr_cascade' ],
2885                                                 [ 'pr_page' => $id ],
2886                                                 $fname
2887                                         )
2888                                 );
2889                         };
2890
2891                         if ( $readLatest ) {
2892                                 $dbr = wfGetDB( DB_MASTER );
2893                                 $rows = $loadRestrictionsFromDb( $dbr );
2894                         } else {
2895                                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
2896                                 $rows = $cache->getWithSetCallback(
2897                                         // Page protections always leave a new null revision
2898                                         $cache->makeKey( 'page-restrictions', 'v1', $id, $this->getLatestRevID() ),
2899                                         $cache::TTL_DAY,
2900                                         function ( $curValue, &$ttl, array &$setOpts ) use ( $loadRestrictionsFromDb ) {
2901                                                 $dbr = wfGetDB( DB_REPLICA );
2902
2903                                                 $setOpts += Database::getCacheSetOptions( $dbr );
2904                                                 $lb = MediaWikiServices::getInstance()->getDBLoadBalancer();
2905                                                 if ( $lb->hasOrMadeRecentMasterChanges() ) {
2906                                                         // @TODO: cleanup Title cache and caller assumption mess in general
2907                                                         $ttl = WANObjectCache::TTL_UNCACHEABLE;
2908                                                 }
2909
2910                                                 return $loadRestrictionsFromDb( $dbr );
2911                                         }
2912                                 );
2913                         }
2914
2915                         $this->loadRestrictionsFromRows( $rows, $oldFashionedRestrictions );
2916                 } else {
2917                         $title_protection = $this->getTitleProtectionInternal();
2918
2919                         if ( $title_protection ) {
2920                                 $now = wfTimestampNow();
2921                                 $expiry = wfGetDB( DB_REPLICA )->decodeExpiry( $title_protection['expiry'] );
2922
2923                                 if ( !$expiry || $expiry > $now ) {
2924                                         // Apply the restrictions
2925                                         $this->mRestrictionsExpiry['create'] = $expiry;
2926                                         $this->mRestrictions['create'] =
2927                                                 explode( ',', trim( $title_protection['permission'] ) );
2928                                 } else { // Get rid of the old restrictions
2929                                         $this->mTitleProtection = false;
2930                                 }
2931                         } else {
2932                                 $this->mRestrictionsExpiry['create'] = 'infinity';
2933                         }
2934                         $this->mRestrictionsLoaded = true;
2935                 }
2936         }
2937
2938         /**
2939          * Flush the protection cache in this object and force reload from the database.
2940          * This is used when updating protection from WikiPage::doUpdateRestrictions().
2941          */
2942         public function flushRestrictions() {
2943                 $this->mRestrictionsLoaded = false;
2944                 $this->mTitleProtection = null;
2945         }
2946
2947         /**
2948          * Purge expired restrictions from the page_restrictions table
2949          *
2950          * This will purge no more than $wgUpdateRowsPerQuery page_restrictions rows
2951          */
2952         static function purgeExpiredRestrictions() {
2953                 if ( wfReadOnly() ) {
2954                         return;
2955                 }
2956
2957                 DeferredUpdates::addUpdate( new AtomicSectionUpdate(
2958                         wfGetDB( DB_MASTER ),
2959                         __METHOD__,
2960                         function ( IDatabase $dbw, $fname ) {
2961                                 $config = MediaWikiServices::getInstance()->getMainConfig();
2962                                 $ids = $dbw->selectFieldValues(
2963                                         'page_restrictions',
2964                                         'pr_id',
2965                                         [ 'pr_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ],
2966                                         $fname,
2967                                         [ 'LIMIT' => $config->get( 'UpdateRowsPerQuery' ) ] // T135470
2968                                 );
2969                                 if ( $ids ) {
2970                                         $dbw->delete( 'page_restrictions', [ 'pr_id' => $ids ], $fname );
2971                                 }
2972                         }
2973                 ) );
2974
2975                 DeferredUpdates::addUpdate( new AtomicSectionUpdate(
2976                         wfGetDB( DB_MASTER ),
2977                         __METHOD__,
2978                         function ( IDatabase $dbw, $fname ) {
2979                                 $dbw->delete(
2980                                         'protected_titles',
2981                                         [ 'pt_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ],
2982                                         $fname
2983                                 );
2984                         }
2985                 ) );
2986         }
2987
2988         /**
2989          * Does this have subpages?  (Warning, usually requires an extra DB query.)
2990          *
2991          * @return bool
2992          */
2993         public function hasSubpages() {
2994                 if (
2995                         !MediaWikiServices::getInstance()->getNamespaceInfo()->
2996                                 hasSubpages( $this->mNamespace )
2997                 ) {
2998                         # Duh
2999                         return false;
3000                 }
3001
3002                 # We dynamically add a member variable for the purpose of this method
3003                 # alone to cache the result.  There's no point in having it hanging
3004                 # around uninitialized in every Title object; therefore we only add it
3005                 # if needed and don't declare it statically.
3006                 if ( $this->mHasSubpages === null ) {
3007                         $this->mHasSubpages = false;
3008                         $subpages = $this->getSubpages( 1 );
3009                         if ( $subpages instanceof TitleArray ) {
3010                                 $this->mHasSubpages = (bool)$subpages->current();
3011                         }
3012                 }
3013
3014                 return $this->mHasSubpages;
3015         }
3016
3017         /**
3018          * Get all subpages of this page.
3019          *
3020          * @param int $limit Maximum number of subpages to fetch; -1 for no limit
3021          * @return TitleArray|array TitleArray, or empty array if this page's namespace
3022          *  doesn't allow subpages
3023          */
3024         public function getSubpages( $limit = -1 ) {
3025                 if (
3026                         !MediaWikiServices::getInstance()->getNamespaceInfo()->
3027                                 hasSubpages( $this->mNamespace )
3028                 ) {
3029                         return [];
3030                 }
3031
3032                 $dbr = wfGetDB( DB_REPLICA );
3033                 $conds['page_namespace'] = $this->mNamespace;
3034                 $conds[] = 'page_title ' . $dbr->buildLike( $this->mDbkeyform . '/', $dbr->anyString() );
3035                 $options = [];
3036                 if ( $limit > -1 ) {
3037                         $options['LIMIT'] = $limit;
3038                 }
3039                 return TitleArray::newFromResult(
3040                         $dbr->select( 'page',
3041                                 [ 'page_id', 'page_namespace', 'page_title', 'page_is_redirect' ],
3042                                 $conds,
3043                                 __METHOD__,
3044                                 $options
3045                         )
3046                 );
3047         }
3048
3049         /**
3050          * Is there a version of this page in the deletion archive?
3051          *
3052          * @return int The number of archived revisions
3053          */
3054         public function isDeleted() {
3055                 if ( $this->mNamespace < 0 ) {
3056                         $n = 0;
3057                 } else {
3058                         $dbr = wfGetDB( DB_REPLICA );
3059
3060                         $n = $dbr->selectField( 'archive', 'COUNT(*)',
3061                                 [ 'ar_namespace' => $this->mNamespace, 'ar_title' => $this->mDbkeyform ],
3062                                 __METHOD__
3063                         );
3064                         if ( $this->mNamespace == NS_FILE ) {
3065                                 $n += $dbr->selectField( 'filearchive', 'COUNT(*)',
3066                                         [ 'fa_name' => $this->mDbkeyform ],
3067                                         __METHOD__
3068                                 );
3069                         }
3070                 }
3071                 return (int)$n;
3072         }
3073
3074         /**
3075          * Is there a version of this page in the deletion archive?
3076          *
3077          * @return bool
3078          */
3079         public function isDeletedQuick() {
3080                 if ( $this->mNamespace < 0 ) {
3081                         return false;
3082                 }
3083                 $dbr = wfGetDB( DB_REPLICA );
3084                 $deleted = (bool)$dbr->selectField( 'archive', '1',
3085                         [ 'ar_namespace' => $this->mNamespace, 'ar_title' => $this->mDbkeyform ],
3086                         __METHOD__
3087                 );
3088                 if ( !$deleted && $this->mNamespace == NS_FILE ) {
3089                         $deleted = (bool)$dbr->selectField( 'filearchive', '1',
3090                                 [ 'fa_name' => $this->mDbkeyform ],
3091                                 __METHOD__
3092                         );
3093                 }
3094                 return $deleted;
3095         }
3096
3097         /**
3098          * Get the article ID for this Title from the link cache,
3099          * adding it if necessary
3100          *
3101          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select
3102          *  for update
3103          * @return int The ID
3104          */
3105         public function getArticleID( $flags = 0 ) {
3106                 if ( $this->mNamespace < 0 ) {
3107                         $this->mArticleID = 0;
3108                         return $this->mArticleID;
3109                 }
3110                 $linkCache = MediaWikiServices::getInstance()->getLinkCache();
3111                 if ( $flags & self::GAID_FOR_UPDATE ) {
3112                         $oldUpdate = $linkCache->forUpdate( true );
3113                         $linkCache->clearLink( $this );
3114                         $this->mArticleID = $linkCache->addLinkObj( $this );
3115                         $linkCache->forUpdate( $oldUpdate );
3116                 } elseif ( $this->mArticleID == -1 ) {
3117                         $this->mArticleID = $linkCache->addLinkObj( $this );
3118                 }
3119                 return $this->mArticleID;
3120         }
3121
3122         /**
3123          * Is this an article that is a redirect page?
3124          * Uses link cache, adding it if necessary
3125          *
3126          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3127          * @return bool
3128          */
3129         public function isRedirect( $flags = 0 ) {
3130                 if ( !is_null( $this->mRedirect ) ) {
3131                         return $this->mRedirect;
3132                 }
3133                 if ( !$this->getArticleID( $flags ) ) {
3134                         $this->mRedirect = false;
3135                         return $this->mRedirect;
3136                 }
3137
3138                 $linkCache = MediaWikiServices::getInstance()->getLinkCache();
3139                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3140                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'redirect' );
3141                 if ( $cached === null ) {
3142                         # Trust LinkCache's state over our own
3143                         # LinkCache is telling us that the page doesn't exist, despite there being cached
3144                         # data relating to an existing page in $this->mArticleID. Updaters should clear
3145                         # LinkCache as appropriate, or use $flags = Title::GAID_FOR_UPDATE. If that flag is
3146                         # set, then LinkCache will definitely be up to date here, since getArticleID() forces
3147                         # LinkCache to refresh its data from the master.
3148                         $this->mRedirect = false;
3149                         return $this->mRedirect;
3150                 }
3151
3152                 $this->mRedirect = (bool)$cached;
3153
3154                 return $this->mRedirect;
3155         }
3156
3157         /**
3158          * What is the length of this page?
3159          * Uses link cache, adding it if necessary
3160          *
3161          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3162          * @return int
3163          */
3164         public function getLength( $flags = 0 ) {
3165                 if ( $this->mLength != -1 ) {
3166                         return $this->mLength;
3167                 }
3168                 if ( !$this->getArticleID( $flags ) ) {
3169                         $this->mLength = 0;
3170                         return $this->mLength;
3171                 }
3172                 $linkCache = MediaWikiServices::getInstance()->getLinkCache();
3173                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3174                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'length' );
3175                 if ( $cached === null ) {
3176                         # Trust LinkCache's state over our own, as for isRedirect()
3177                         $this->mLength = 0;
3178                         return $this->mLength;
3179                 }
3180
3181                 $this->mLength = intval( $cached );
3182
3183                 return $this->mLength;
3184         }
3185
3186         /**
3187          * What is the page_latest field for this page?
3188          *
3189          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3190          * @return int Int or 0 if the page doesn't exist
3191          */
3192         public function getLatestRevID( $flags = 0 ) {
3193                 if ( !( $flags & self::GAID_FOR_UPDATE ) && $this->mLatestID !== false ) {
3194                         return intval( $this->mLatestID );
3195                 }
3196                 if ( !$this->getArticleID( $flags ) ) {
3197                         $this->mLatestID = 0;
3198                         return $this->mLatestID;
3199                 }
3200                 $linkCache = MediaWikiServices::getInstance()->getLinkCache();
3201                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3202                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'revision' );
3203                 if ( $cached === null ) {
3204                         # Trust LinkCache's state over our own, as for isRedirect()
3205                         $this->mLatestID = 0;
3206                         return $this->mLatestID;
3207                 }
3208
3209                 $this->mLatestID = intval( $cached );
3210
3211                 return $this->mLatestID;
3212         }
3213
3214         /**
3215          * This clears some fields in this object, and clears any associated
3216          * keys in the "bad links" section of the link cache.
3217          *
3218          * - This is called from WikiPage::doEditContent() and WikiPage::insertOn() to allow
3219          * loading of the new page_id. It's also called from
3220          * WikiPage::doDeleteArticleReal()
3221          *
3222          * @param int $newid The new Article ID
3223          */
3224         public function resetArticleID( $newid ) {
3225                 $linkCache = MediaWikiServices::getInstance()->getLinkCache();
3226                 $linkCache->clearLink( $this );
3227
3228                 if ( $newid === false ) {
3229                         $this->mArticleID = -1;
3230                 } else {
3231                         $this->mArticleID = intval( $newid );
3232                 }
3233                 $this->mRestrictionsLoaded = false;
3234                 $this->mRestrictions = [];
3235                 $this->mOldRestrictions = false;
3236                 $this->mRedirect = null;
3237                 $this->mLength = -1;
3238                 $this->mLatestID = false;
3239                 $this->mContentModel = false;
3240                 $this->mEstimateRevisions = null;
3241                 $this->mPageLanguage = false;
3242                 $this->mDbPageLanguage = false;
3243                 $this->mIsBigDeletion = null;
3244         }
3245
3246         public static function clearCaches() {
3247                 $linkCache = MediaWikiServices::getInstance()->getLinkCache();
3248                 $linkCache->clear();
3249
3250                 $titleCache = self::getTitleCache();
3251                 $titleCache->clear();
3252         }
3253
3254         /**
3255          * Capitalize a text string for a title if it belongs to a namespace that capitalizes
3256          *
3257          * @param string $text Containing title to capitalize
3258          * @param int $ns Namespace index, defaults to NS_MAIN
3259          * @return string Containing capitalized title
3260          */
3261         public static function capitalize( $text, $ns = NS_MAIN ) {
3262                 $services = MediaWikiServices::getInstance();
3263                 if ( $services->getNamespaceInfo()->isCapitalized( $ns ) ) {
3264                         return $services->getContentLanguage()->ucfirst( $text );
3265                 } else {
3266                         return $text;
3267                 }
3268         }
3269
3270         /**
3271          * Secure and split - main initialisation function for this object
3272          *
3273          * Assumes that mDbkeyform has been set, and is urldecoded
3274          * and uses underscores, but not otherwise munged.  This function
3275          * removes illegal characters, splits off the interwiki and
3276          * namespace prefixes, sets the other forms, and canonicalizes
3277          * everything.
3278          *
3279          * @throws MalformedTitleException On invalid titles
3280          * @return bool True on success
3281          */
3282         private function secureAndSplit() {
3283                 // @note: splitTitleString() is a temporary hack to allow MediaWikiTitleCodec to share
3284                 //        the parsing code with Title, while avoiding massive refactoring.
3285                 // @todo: get rid of secureAndSplit, refactor parsing code.
3286                 // @note: getTitleParser() returns a TitleParser implementation which does not have a
3287                 //        splitTitleString method, but the only implementation (MediaWikiTitleCodec) does
3288                 /** @var MediaWikiTitleCodec $titleCodec */
3289                 $titleCodec = MediaWikiServices::getInstance()->getTitleParser();
3290                 // MalformedTitleException can be thrown here
3291                 $parts = $titleCodec->splitTitleString( $this->mDbkeyform, $this->mDefaultNamespace );
3292
3293                 # Fill fields
3294                 $this->setFragment( '#' . $parts['fragment'] );
3295                 $this->mInterwiki = $parts['interwiki'];
3296                 $this->mLocalInterwiki = $parts['local_interwiki'];
3297                 $this->mNamespace = $parts['namespace'];
3298                 $this->mUserCaseDBKey = $parts['user_case_dbkey'];
3299
3300                 $this->mDbkeyform = $parts['dbkey'];
3301                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
3302                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
3303
3304                 # We already know that some pages won't be in the database!
3305                 if ( $this->isExternal() || $this->isSpecialPage() ) {
3306                         $this->mArticleID = 0;
3307                 }
3308
3309                 return true;
3310         }
3311
3312         /**
3313          * Get an array of Title objects linking to this Title
3314          * Also stores the IDs in the link cache.
3315          *
3316          * WARNING: do not use this function on arbitrary user-supplied titles!
3317          * On heavily-used templates it will max out the memory.
3318          *
3319          * @param array $options May be FOR UPDATE
3320          * @param string $table Table name
3321          * @param string $prefix Fields prefix
3322          * @return Title[] Array of Title objects linking here
3323          */
3324         public function getLinksTo( $options = [], $table = 'pagelinks', $prefix = 'pl' ) {
3325                 if ( count( $options ) > 0 ) {
3326                         $db = wfGetDB( DB_MASTER );
3327                 } else {
3328                         $db = wfGetDB( DB_REPLICA );
3329                 }
3330
3331                 $res = $db->select(
3332                         [ 'page', $table ],
3333                         self::getSelectFields(),
3334                         [
3335                                 "{$prefix}_from=page_id",
3336                                 "{$prefix}_namespace" => $this->mNamespace,
3337                                 "{$prefix}_title" => $this->mDbkeyform ],
3338                         __METHOD__,
3339                         $options
3340                 );
3341
3342                 $retVal = [];
3343                 if ( $res->numRows() ) {
3344                         $linkCache = MediaWikiServices::getInstance()->getLinkCache();
3345                         foreach ( $res as $row ) {
3346                                 $titleObj = self::makeTitle( $row->page_namespace, $row->page_title );
3347                                 if ( $titleObj ) {
3348                                         $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3349                                         $retVal[] = $titleObj;
3350                                 }
3351                         }
3352                 }
3353                 return $retVal;
3354         }
3355
3356         /**
3357          * Get an array of Title objects using this Title as a template
3358          * Also stores the IDs in the link cache.
3359          *
3360          * WARNING: do not use this function on arbitrary user-supplied titles!
3361          * On heavily-used templates it will max out the memory.
3362          *
3363          * @param array $options Query option to Database::select()
3364          * @return Title[] Array of Title the Title objects linking here
3365          */
3366         public function getTemplateLinksTo( $options = [] ) {
3367                 return $this->getLinksTo( $options, 'templatelinks', 'tl' );
3368         }
3369
3370         /**
3371          * Get an array of Title objects linked from this Title
3372          * Also stores the IDs in the link cache.
3373          *
3374          * WARNING: do not use this function on arbitrary user-supplied titles!
3375          * On heavily-used templates it will max out the memory.
3376          *
3377          * @param array $options Query option to Database::select()
3378          * @param string $table Table name
3379          * @param string $prefix Fields prefix
3380          * @return array Array of Title objects linking here
3381          */
3382         public function getLinksFrom( $options = [], $table = 'pagelinks', $prefix = 'pl' ) {
3383                 $id = $this->getArticleID();
3384
3385                 # If the page doesn't exist; there can't be any link from this page
3386                 if ( !$id ) {
3387                         return [];
3388                 }
3389
3390                 $db = wfGetDB( DB_REPLICA );
3391
3392                 $blNamespace = "{$prefix}_namespace";
3393                 $blTitle = "{$prefix}_title";
3394
3395                 $pageQuery = WikiPage::getQueryInfo();
3396                 $res = $db->select(
3397                         [ $table, 'nestpage' => $pageQuery['tables'] ],
3398                         array_merge(
3399                                 [ $blNamespace, $blTitle ],
3400                                 $pageQuery['fields']
3401                         ),
3402                         [ "{$prefix}_from" => $id ],
3403                         __METHOD__,
3404                         $options,
3405                         [ 'nestpage' => [
3406                                 'LEFT JOIN',
3407                                 [ "page_namespace=$blNamespace", "page_title=$blTitle" ]
3408                         ] ] + $pageQuery['joins']
3409                 );
3410
3411                 $retVal = [];
3412                 $linkCache = MediaWikiServices::getInstance()->getLinkCache();
3413                 foreach ( $res as $row ) {
3414                         if ( $row->page_id ) {
3415                                 $titleObj = self::newFromRow( $row );
3416                         } else {
3417                                 $titleObj = self::makeTitle( $row->$blNamespace, $row->$blTitle );
3418                                 $linkCache->addBadLinkObj( $titleObj );
3419                         }
3420                         $retVal[] = $titleObj;
3421                 }
3422
3423                 return $retVal;
3424         }
3425
3426         /**
3427          * Get an array of Title objects used on this Title as a template
3428          * Also stores the IDs in the link cache.
3429          *
3430          * WARNING: do not use this function on arbitrary user-supplied titles!
3431          * On heavily-used templates it will max out the memory.
3432          *
3433          * @param array $options May be FOR UPDATE
3434          * @return Title[] Array of Title the Title objects used here
3435          */
3436         public function getTemplateLinksFrom( $options = [] ) {
3437                 return $this->getLinksFrom( $options, 'templatelinks', 'tl' );
3438         }
3439
3440         /**
3441          * Get an array of Title objects referring to non-existent articles linked
3442          * from this page.
3443          *
3444          * @todo check if needed (used only in SpecialBrokenRedirects.php, and
3445          *   should use redirect table in this case).
3446          * @return Title[] Array of Title the Title objects
3447          */
3448         public function getBrokenLinksFrom() {
3449                 if ( $this->getArticleID() == 0 ) {
3450                         # All links from article ID 0 are false positives
3451                         return [];
3452                 }
3453
3454                 $dbr = wfGetDB( DB_REPLICA );
3455                 $res = $dbr->select(
3456                         [ 'page', 'pagelinks' ],
3457                         [ 'pl_namespace', 'pl_title' ],
3458                         [
3459                                 'pl_from' => $this->getArticleID(),
3460                                 'page_namespace IS NULL'
3461                         ],
3462                         __METHOD__, [],
3463                         [
3464                                 'page' => [
3465                                         'LEFT JOIN',
3466                                         [ 'pl_namespace=page_namespace', 'pl_title=page_title' ]
3467                                 ]
3468                         ]
3469                 );
3470
3471                 $retVal = [];
3472                 foreach ( $res as $row ) {
3473                         $retVal[] = self::makeTitle( $row->pl_namespace, $row->pl_title );
3474                 }
3475                 return $retVal;
3476         }
3477
3478         /**
3479          * Get a list of URLs to purge from the CDN cache when this
3480          * page changes
3481          *
3482          * @return string[] Array of String the URLs
3483          */
3484         public function getCdnUrls() {
3485                 $urls = [
3486                         $this->getInternalURL(),
3487                         $this->getInternalURL( 'action=history' )
3488                 ];
3489
3490                 $pageLang = $this->getPageLanguage();
3491                 if ( $pageLang->hasVariants() ) {
3492                         $variants = $pageLang->getVariants();
3493                         foreach ( $variants as $vCode ) {
3494                                 $urls[] = $this->getInternalURL( $vCode );
3495                         }
3496                 }
3497
3498                 // If we are looking at a css/js user subpage, purge the action=raw.
3499                 if ( $this->isUserJsConfigPage() ) {
3500                         $urls[] = $this->getInternalURL( 'action=raw&ctype=text/javascript' );
3501                 } elseif ( $this->isUserJsonConfigPage() ) {
3502                         $urls[] = $this->getInternalURL( 'action=raw&ctype=application/json' );
3503                 } elseif ( $this->isUserCssConfigPage() ) {
3504                         $urls[] = $this->getInternalURL( 'action=raw&ctype=text/css' );
3505                 }
3506
3507                 Hooks::run( 'TitleSquidURLs', [ $this, &$urls ] );
3508                 return $urls;
3509         }
3510
3511         /**
3512          * Purge all applicable CDN URLs
3513          */
3514         public function purgeSquid() {
3515                 DeferredUpdates::addUpdate(
3516                         new CdnCacheUpdate( $this->getCdnUrls() ),
3517                         DeferredUpdates::PRESEND
3518                 );
3519         }
3520
3521         /**
3522          * Check whether a given move operation would be valid.
3523          * Returns true if ok, or a getUserPermissionsErrors()-like array otherwise
3524          *
3525          * @deprecated since 1.25, use MovePage's methods instead
3526          * @param Title &$nt The new title
3527          * @param bool $auth Whether to check user permissions (uses $wgUser)
3528          * @param string $reason Is the log summary of the move, used for spam checking
3529          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3530          */
3531         public function isValidMoveOperation( &$nt, $auth = true, $reason = '' ) {
3532                 wfDeprecated( __METHOD__, '1.25' );
3533
3534                 global $wgUser;
3535
3536                 if ( !( $nt instanceof Title ) ) {
3537                         // Normally we'd add this to $errors, but we'll get
3538                         // lots of syntax errors if $nt is not an object
3539                         return [ [ 'badtitletext' ] ];
3540                 }
3541
3542                 $mp = MediaWikiServices::getInstance()->getMovePageFactory()->newMovePage( $this, $nt );
3543                 $errors = $mp->isValidMove()->getErrorsArray();
3544                 if ( $auth ) {
3545                         $errors = wfMergeErrorArrays(
3546                                 $errors,
3547                                 $mp->checkPermissions( $wgUser, $reason )->getErrorsArray()
3548                         );
3549                 }
3550
3551                 return $errors ?: true;
3552         }
3553
3554         /**
3555          * Move a title to a new location
3556          *
3557          * @deprecated since 1.25, use the MovePage class instead
3558          * @param Title &$nt The new title
3559          * @param bool $auth Indicates whether $wgUser's permissions
3560          *  should be checked
3561          * @param string $reason The reason for the move
3562          * @param bool $createRedirect Whether to create a redirect from the old title to the new title.
3563          *  Ignored if the user doesn't have the suppressredirect right.
3564          * @param array $changeTags Applied to the entry in the move log and redirect page revision
3565          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3566          */
3567         public function moveTo( &$nt, $auth = true, $reason = '', $createRedirect = true,
3568                 array $changeTags = []
3569         ) {
3570                 wfDeprecated( __METHOD__, '1.25' );
3571
3572                 global $wgUser;
3573
3574                 $mp = MediaWikiServices::getInstance()->getMovePageFactory()->newMovePage( $this, $nt );
3575                 $method = $auth ? 'moveIfAllowed' : 'move';
3576                 $status = $mp->$method( $wgUser, $reason, $createRedirect, $changeTags );
3577                 if ( $status->isOK() ) {
3578                         return true;
3579                 } else {
3580                         return $status->getErrorsArray();
3581                 }
3582         }
3583
3584         /**
3585          * Move this page's subpages to be subpages of $nt
3586          *
3587          * @deprecated since 1.34, use MovePage instead
3588          * @param Title $nt Move target
3589          * @param bool $auth Whether $wgUser's permissions should be checked
3590          * @param string $reason The reason for the move
3591          * @param bool $createRedirect Whether to create redirects from the old subpages to
3592          *     the new ones Ignored if the user doesn't have the 'suppressredirect' right
3593          * @param array $changeTags Applied to the entry in the move log and redirect page revision
3594          * @return array Array with old page titles as keys, and strings (new page titles) or
3595          *     getUserPermissionsErrors()-like arrays (errors) as values, or a
3596          *     getUserPermissionsErrors()-like error array with numeric indices if
3597          *     no pages were moved
3598          */
3599         public function moveSubpages( $nt, $auth = true, $reason = '', $createRedirect = true,
3600                 array $changeTags = []
3601         ) {
3602                 wfDeprecated( __METHOD__, '1.34' );
3603
3604                 global $wgUser;
3605
3606                 $mp = new MovePage( $this, $nt );
3607                 $method = $auth ? 'moveSubpagesIfAllowed' : 'moveSubpages';
3608                 $result = $mp->$method( $wgUser, $reason, $createRedirect, $changeTags );
3609
3610                 if ( !$result->isOk() ) {
3611                         return $result->getErrorsArray();
3612                 }
3613
3614                 $retval = [];
3615                 foreach ( $result->getValue() as $key => $status ) {
3616                         if ( $status->isOK() ) {
3617                                 $retval[$key] = $status->getValue();
3618                         } else {
3619                                 $retval[$key] = $status->getErrorsArray();
3620                         }
3621                 }
3622                 return $retval;
3623         }
3624
3625         /**
3626          * Checks if this page is just a one-rev redirect.
3627          * Adds lock, so don't use just for light purposes.
3628          *
3629          * @return bool
3630          */
3631         public function isSingleRevRedirect() {
3632                 global $wgContentHandlerUseDB;
3633
3634                 $dbw = wfGetDB( DB_MASTER );
3635
3636                 # Is it a redirect?
3637                 $fields = [ 'page_is_redirect', 'page_latest', 'page_id' ];
3638                 if ( $wgContentHandlerUseDB ) {
3639                         $fields[] = 'page_content_model';
3640                 }
3641
3642                 $row = $dbw->selectRow( 'page',
3643                         $fields,
3644                         $this->pageCond(),
3645                         __METHOD__,
3646                         [ 'FOR UPDATE' ]
3647                 );
3648                 # Cache some fields we may want
3649                 $this->mArticleID = $row ? intval( $row->page_id ) : 0;
3650                 $this->mRedirect = $row ? (bool)$row->page_is_redirect : false;
3651                 $this->mLatestID = $row ? intval( $row->page_latest ) : false;
3652                 $this->mContentModel = $row && isset( $row->page_content_model )
3653                         ? strval( $row->page_content_model )
3654                         : false;
3655
3656                 if ( !$this->mRedirect ) {
3657                         return false;
3658                 }
3659                 # Does the article have a history?
3660                 $row = $dbw->selectField( [ 'page', 'revision' ],
3661                         'rev_id',
3662                         [ 'page_namespace' => $this->mNamespace,
3663                                 'page_title' => $this->mDbkeyform,
3664                                 'page_id=rev_page',
3665                                 'page_latest != rev_id'
3666                         ],
3667                         __METHOD__,
3668                         [ 'FOR UPDATE' ]
3669                 );
3670                 # Return true if there was no history
3671                 return ( $row === false );
3672         }
3673
3674         /**
3675          * Checks if $this can be moved to a given Title
3676          * - Selects for update, so don't call it unless you mean business
3677          *
3678          * @deprecated since 1.25, use MovePage's methods instead
3679          * @param Title $nt The new title to check
3680          * @return bool
3681          */
3682         public function isValidMoveTarget( $nt ) {
3683                 wfDeprecated( __METHOD__, '1.25' );
3684
3685                 # Is it an existing file?
3686                 if ( $nt->getNamespace() == NS_FILE ) {
3687                         $file = MediaWikiServices::getInstance()->getRepoGroup()->getLocalRepo()
3688                                 ->newFile( $nt );
3689                         $file->load( File::READ_LATEST );
3690                         if ( $file->exists() ) {
3691                                 wfDebug( __METHOD__ . ": file exists\n" );
3692                                 return false;
3693                         }
3694                 }
3695                 # Is it a redirect with no history?
3696                 if ( !$nt->isSingleRevRedirect() ) {
3697                         wfDebug( __METHOD__ . ": not a one-rev redirect\n" );
3698                         return false;
3699                 }
3700                 # Get the article text
3701                 $rev = Revision::newFromTitle( $nt, false, Revision::READ_LATEST );
3702                 if ( !is_object( $rev ) ) {
3703                         return false;
3704                 }
3705                 $content = $rev->getContent();
3706                 # Does the redirect point to the source?
3707                 # Or is it a broken self-redirect, usually caused by namespace collisions?
3708                 $redirTitle = $content ? $content->getRedirectTarget() : null;
3709
3710                 if ( $redirTitle ) {
3711                         if ( $redirTitle->getPrefixedDBkey() != $this->getPrefixedDBkey() &&
3712                                 $redirTitle->getPrefixedDBkey() != $nt->getPrefixedDBkey() ) {
3713                                 wfDebug( __METHOD__ . ": redirect points to other page\n" );
3714                                 return false;
3715                         } else {
3716                                 return true;
3717                         }
3718                 } else {
3719                         # Fail safe (not a redirect after all. strange.)
3720                         wfDebug( __METHOD__ . ": failsafe: database sais " . $nt->getPrefixedDBkey() .
3721                                                 " is a redirect, but it doesn't contain a valid redirect.\n" );
3722                         return false;
3723                 }
3724         }
3725
3726         /**
3727          * Get categories to which this Title belongs and return an array of
3728          * categories' names.
3729          *
3730          * @return array Array of parents in the form:
3731          *     $parent => $currentarticle
3732          */
3733         public function getParentCategories() {
3734                 $data = [];
3735
3736                 $titleKey = $this->getArticleID();
3737
3738                 if ( $titleKey === 0 ) {
3739                         return $data;
3740                 }
3741
3742                 $dbr = wfGetDB( DB_REPLICA );
3743
3744                 $res = $dbr->select(
3745                         'categorylinks',
3746                         'cl_to',
3747                         [ 'cl_from' => $titleKey ],
3748                         __METHOD__
3749                 );
3750
3751                 if ( $res->numRows() > 0 ) {
3752                         $contLang = MediaWikiServices::getInstance()->getContentLanguage();
3753                         foreach ( $res as $row ) {
3754                                 // $data[] = Title::newFromText( $contLang->getNsText ( NS_CATEGORY ).':'.$row->cl_to);
3755                                 $data[$contLang->getNsText( NS_CATEGORY ) . ':' . $row->cl_to] =
3756                                         $this->getFullText();
3757                         }
3758                 }
3759                 return $data;
3760         }
3761
3762         /**
3763          * Get a tree of parent categories
3764          *
3765          * @param array $children Array with the children in the keys, to check for circular refs
3766          * @return array Tree of parent categories
3767          */
3768         public function getParentCategoryTree( $children = [] ) {
3769                 $stack = [];
3770                 $parents = $this->getParentCategories();
3771
3772                 if ( $parents ) {
3773                         foreach ( $parents as $parent => $current ) {
3774                                 if ( array_key_exists( $parent, $children ) ) {
3775                                         # Circular reference
3776                                         $stack[$parent] = [];
3777                                 } else {
3778                                         $nt = self::newFromText( $parent );
3779                                         if ( $nt ) {
3780                                                 $stack[$parent] = $nt->getParentCategoryTree( $children + [ $parent => 1 ] );
3781                                         }
3782                                 }
3783                         }
3784                 }
3785
3786                 return $stack;
3787         }
3788
3789         /**
3790          * Get an associative array for selecting this title from
3791          * the "page" table
3792          *
3793          * @return array Array suitable for the $where parameter of DB::select()
3794          */
3795         public function pageCond() {
3796                 if ( $this->mArticleID > 0 ) {
3797                         // PK avoids secondary lookups in InnoDB, shouldn't hurt other DBs
3798                         return [ 'page_id' => $this->mArticleID ];
3799                 } else {
3800                         return [ 'page_namespace' => $this->mNamespace, 'page_title' => $this->mDbkeyform ];
3801                 }
3802         }
3803
3804         /**
3805          * Get next/previous revision ID relative to another revision ID
3806          * @param int $revId Revision ID. Get the revision that was before this one.
3807          * @param int $flags Title::GAID_FOR_UPDATE
3808          * @param string $dir 'next' or 'prev'
3809          * @return int|bool New revision ID, or false if none exists
3810          */
3811         private function getRelativeRevisionID( $revId, $flags, $dir ) {
3812                 $rl = MediaWikiServices::getInstance()->getRevisionLookup();
3813                 $rlFlags = $flags === self::GAID_FOR_UPDATE ? IDBAccessObject::READ_LATEST : 0;
3814                 $rev = $rl->getRevisionById( $revId, $rlFlags );
3815                 if ( !$rev ) {
3816                         return false;
3817                 }
3818                 $oldRev = $dir === 'next'
3819                         ? $rl->getNextRevision( $rev, $rlFlags )
3820                         : $rl->getPreviousRevision( $rev, $rlFlags );
3821                 if ( !$oldRev ) {
3822                         return false;
3823                 }
3824                 return $oldRev->getId();
3825         }
3826
3827         /**
3828          * Get the revision ID of the previous revision
3829          *
3830          * @deprecated since 1.34, use RevisionLookup::getPreviousRevision
3831          * @param int $revId Revision ID. Get the revision that was before this one.
3832          * @param int $flags Title::GAID_FOR_UPDATE
3833          * @return int|bool Old revision ID, or false if none exists
3834          */
3835         public function getPreviousRevisionID( $revId, $flags = 0 ) {
3836                 return $this->getRelativeRevisionID( $revId, $flags, 'prev' );
3837         }
3838
3839         /**
3840          * Get the revision ID of the next revision
3841          *
3842          * @deprecated since 1.34, use RevisionLookup::getNextRevision
3843          * @param int $revId Revision ID. Get the revision that was after this one.
3844          * @param int $flags Title::GAID_FOR_UPDATE
3845          * @return int|bool Next revision ID, or false if none exists
3846          */
3847         public function getNextRevisionID( $revId, $flags = 0 ) {
3848                 return $this->getRelativeRevisionID( $revId, $flags, 'next' );
3849         }
3850
3851         /**
3852          * Get the first revision of the page
3853          *
3854          * @param int $flags Title::GAID_FOR_UPDATE
3855          * @return Revision|null If page doesn't exist
3856          */
3857         public function getFirstRevision( $flags = 0 ) {
3858                 $pageId = $this->getArticleID( $flags );
3859                 if ( $pageId ) {
3860                         $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_REPLICA );
3861                         $revQuery = Revision::getQueryInfo();
3862                         $row = $db->selectRow( $revQuery['tables'], $revQuery['fields'],
3863                                 [ 'rev_page' => $pageId ],
3864                                 __METHOD__,
3865                                 [
3866                                         'ORDER BY' => 'rev_timestamp ASC, rev_id ASC',
3867                                         'IGNORE INDEX' => [ 'revision' => 'rev_timestamp' ], // See T159319
3868                                 ],
3869                                 $revQuery['joins']
3870                         );
3871                         if ( $row ) {
3872                                 return new Revision( $row, 0, $this );
3873                         }
3874                 }
3875                 return null;
3876         }
3877
3878         /**
3879          * Get the oldest revision timestamp of this page
3880          *
3881          * @param int $flags Title::GAID_FOR_UPDATE
3882          * @return string|null MW timestamp
3883          */
3884         public function getEarliestRevTime( $flags = 0 ) {
3885                 $rev = $this->getFirstRevision( $flags );
3886                 return $rev ? $rev->getTimestamp() : null;
3887         }
3888
3889         /**
3890          * Check if this is a new page
3891          *
3892          * @return bool
3893          */
3894         public function isNewPage() {
3895                 $dbr = wfGetDB( DB_REPLICA );
3896                 return (bool)$dbr->selectField( 'page', 'page_is_new', $this->pageCond(), __METHOD__ );
3897         }
3898
3899         /**
3900          * Check whether the number of revisions of this page surpasses $wgDeleteRevisionsLimit
3901          *
3902          * @return bool
3903          */
3904         public function isBigDeletion() {
3905                 global $wgDeleteRevisionsLimit;
3906
3907                 if ( !$wgDeleteRevisionsLimit ) {
3908                         return false;
3909                 }
3910
3911                 if ( $this->mIsBigDeletion === null ) {
3912                         $dbr = wfGetDB( DB_REPLICA );
3913
3914                         $revCount = $dbr->selectRowCount(
3915                                 'revision',
3916                                 '1',
3917                                 [ 'rev_page' => $this->getArticleID() ],
3918                                 __METHOD__,
3919                                 [ 'LIMIT' => $wgDeleteRevisionsLimit + 1 ]
3920                         );
3921
3922                         $this->mIsBigDeletion = $revCount > $wgDeleteRevisionsLimit;
3923                 }
3924
3925                 return $this->mIsBigDeletion;
3926         }
3927
3928         /**
3929          * Get the approximate revision count of this page.
3930          *
3931          * @return int
3932          */
3933         public function estimateRevisionCount() {
3934                 if ( !$this->exists() ) {
3935                         return 0;
3936                 }
3937
3938                 if ( $this->mEstimateRevisions === null ) {
3939                         $dbr = wfGetDB( DB_REPLICA );
3940                         $this->mEstimateRevisions = $dbr->estimateRowCount( 'revision', '*',
3941                                 [ 'rev_page' => $this->getArticleID() ], __METHOD__ );
3942                 }
3943
3944                 return $this->mEstimateRevisions;
3945         }
3946
3947         /**
3948          * Get the number of revisions between the given revision.
3949          * Used for diffs and other things that really need it.
3950          *
3951          * @param int|Revision $old Old revision or rev ID (first before range)
3952          * @param int|Revision $new New revision or rev ID (first after range)
3953          * @param int|null $max Limit of Revisions to count, will be incremented to detect truncations
3954          * @return int Number of revisions between these revisions.
3955          */
3956         public function countRevisionsBetween( $old, $new, $max = null ) {
3957                 if ( !( $old instanceof Revision ) ) {
3958                         $old = Revision::newFromTitle( $this, (int)$old );
3959                 }
3960                 if ( !( $new instanceof Revision ) ) {
3961                         $new = Revision::newFromTitle( $this, (int)$new );
3962                 }
3963                 if ( !$old || !$new ) {
3964                         return 0; // nothing to compare
3965                 }
3966                 $dbr = wfGetDB( DB_REPLICA );
3967                 $conds = [
3968                         'rev_page' => $this->getArticleID(),
3969                         'rev_timestamp > ' . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
3970                         'rev_timestamp < ' . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
3971                 ];
3972                 if ( $max !== null ) {
3973                         return $dbr->selectRowCount( 'revision', '1',
3974                                 $conds,
3975                                 __METHOD__,
3976                                 [ 'LIMIT' => $max + 1 ] // extra to detect truncation
3977                         );
3978                 } else {
3979                         return (int)$dbr->selectField( 'revision', 'count(*)', $conds, __METHOD__ );
3980                 }
3981         }
3982
3983         /**
3984          * Get the authors between the given revisions or revision IDs.
3985          * Used for diffs and other things that really need it.
3986          *
3987          * @since 1.23
3988          *
3989          * @param int|Revision $old Old revision or rev ID (first before range by default)
3990          * @param int|Revision $new New revision or rev ID (first after range by default)
3991          * @param int $limit Maximum number of authors
3992          * @param string|array $options (Optional): Single option, or an array of options:
3993          *     'include_old' Include $old in the range; $new is excluded.
3994          *     'include_new' Include $new in the range; $old is excluded.
3995          *     'include_both' Include both $old and $new in the range.
3996          *     Unknown option values are ignored.
3997          * @return array|null Names of revision authors in the range; null if not both revisions exist
3998          */
3999         public function getAuthorsBetween( $old, $new, $limit, $options = [] ) {
4000                 if ( !( $old instanceof Revision ) ) {
4001                         $old = Revision::newFromTitle( $this, (int)$old );
4002                 }
4003                 if ( !( $new instanceof Revision ) ) {
4004                         $new = Revision::newFromTitle( $this, (int)$new );
4005                 }
4006                 // XXX: what if Revision objects are passed in, but they don't refer to this title?
4007                 // Add $old->getPage() != $new->getPage() || $old->getPage() != $this->getArticleID()
4008                 // in the sanity check below?
4009                 if ( !$old || !$new ) {
4010                         return null; // nothing to compare
4011                 }
4012                 $authors = [];
4013                 $old_cmp = '>';
4014                 $new_cmp = '<';
4015                 $options = (array)$options;
4016                 if ( in_array( 'include_old', $options ) ) {
4017                         $old_cmp = '>=';
4018                 }
4019                 if ( in_array( 'include_new', $options ) ) {
4020                         $new_cmp = '<=';
4021                 }
4022                 if ( in_array( 'include_both', $options ) ) {
4023                         $old_cmp = '>=';
4024                         $new_cmp = '<=';
4025                 }
4026                 // No DB query needed if $old and $new are the same or successive revisions:
4027                 if ( $old->getId() === $new->getId() ) {
4028                         return ( $old_cmp === '>' && $new_cmp === '<' ) ?
4029                                 [] :
4030                                 [ $old->getUserText( RevisionRecord::RAW ) ];
4031                 } elseif ( $old->getId() === $new->getParentId() ) {
4032                         if ( $old_cmp === '>=' && $new_cmp === '<=' ) {
4033                                 $authors[] = $oldUserText = $old->getUserText( RevisionRecord::RAW );
4034                                 $newUserText = $new->getUserText( RevisionRecord::RAW );
4035                                 if ( $oldUserText != $newUserText ) {
4036                                         $authors[] = $newUserText;
4037                                 }
4038                         } elseif ( $old_cmp === '>=' ) {
4039                                 $authors[] = $old->getUserText( RevisionRecord::RAW );
4040                         } elseif ( $new_cmp === '<=' ) {
4041                                 $authors[] = $new->getUserText( RevisionRecord::RAW );
4042                         }
4043                         return $authors;
4044                 }
4045                 $dbr = wfGetDB( DB_REPLICA );
4046                 $revQuery = Revision::getQueryInfo();
4047                 $authors = $dbr->selectFieldValues(
4048                         $revQuery['tables'],
4049                         $revQuery['fields']['rev_user_text'],
4050                         [
4051                                 'rev_page' => $this->getArticleID(),
4052                                 "rev_timestamp $old_cmp " . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4053                                 "rev_timestamp $new_cmp " . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4054                         ], __METHOD__,
4055                         [ 'DISTINCT', 'LIMIT' => $limit + 1 ], // add one so caller knows it was truncated
4056                         $revQuery['joins']
4057                 );
4058                 return $authors;
4059         }
4060
4061         /**
4062          * Get the number of authors between the given revisions or revision IDs.
4063          * Used for diffs and other things that really need it.
4064          *
4065          * @param int|Revision $old Old revision or rev ID (first before range by default)
4066          * @param int|Revision $new New revision or rev ID (first after range by default)
4067          * @param int $limit Maximum number of authors
4068          * @param string|array $options (Optional): Single option, or an array of options:
4069          *     'include_old' Include $old in the range; $new is excluded.
4070          *     'include_new' Include $new in the range; $old is excluded.
4071          *     'include_both' Include both $old and $new in the range.
4072          *     Unknown option values are ignored.
4073          * @return int Number of revision authors in the range; zero if not both revisions exist
4074          */
4075         public function countAuthorsBetween( $old, $new, $limit, $options = [] ) {
4076                 $authors = $this->getAuthorsBetween( $old, $new, $limit, $options );
4077                 return $authors ? count( $authors ) : 0;
4078         }
4079
4080         /**
4081          * Compare with another title.
4082          *
4083          * @param LinkTarget $title
4084          * @return bool
4085          */
4086         public function equals( LinkTarget $title ) {
4087                 // Note: === is necessary for proper matching of number-like titles.
4088                 return $this->mInterwiki === $title->getInterwiki()
4089                         && $this->mNamespace == $title->getNamespace()
4090                         && $this->mDbkeyform === $title->getDBkey();
4091         }
4092
4093         /**
4094          * Check if this title is a subpage of another title
4095          *
4096          * @param Title $title
4097          * @return bool
4098          */
4099         public function isSubpageOf( Title $title ) {
4100                 return $this->mInterwiki === $title->mInterwiki
4101                         && $this->mNamespace == $title->mNamespace
4102                         && strpos( $this->mDbkeyform, $title->mDbkeyform . '/' ) === 0;
4103         }
4104
4105         /**
4106          * Check if page exists.  For historical reasons, this function simply
4107          * checks for the existence of the title in the page table, and will
4108          * thus return false for interwiki links, special pages and the like.
4109          * If you want to know if a title can be meaningfully viewed, you should
4110          * probably call the isKnown() method instead.
4111          *
4112          * @param int $flags An optional bit field; may be Title::GAID_FOR_UPDATE to check
4113          *   from master/for update
4114          * @return bool
4115          */
4116         public function exists( $flags = 0 ) {
4117                 $exists = $this->getArticleID( $flags ) != 0;
4118                 Hooks::run( 'TitleExists', [ $this, &$exists ] );
4119                 return $exists;
4120         }
4121
4122         /**
4123          * Should links to this title be shown as potentially viewable (i.e. as
4124          * "bluelinks"), even if there's no record by this title in the page
4125          * table?
4126          *
4127          * This function is semi-deprecated for public use, as well as somewhat
4128          * misleadingly named.  You probably just want to call isKnown(), which
4129          * calls this function internally.
4130          *
4131          * (ISSUE: Most of these checks are cheap, but the file existence check
4132          * can potentially be quite expensive.  Including it here fixes a lot of
4133          * existing code, but we might want to add an optional parameter to skip
4134          * it and any other expensive checks.)
4135          *
4136          * @return bool
4137          */
4138         public function isAlwaysKnown() {
4139                 $isKnown = null;
4140
4141                 /**
4142                  * Allows overriding default behavior for determining if a page exists.
4143                  * If $isKnown is kept as null, regular checks happen. If it's
4144                  * a boolean, this value is returned by the isKnown method.
4145                  *
4146                  * @since 1.20
4147                  *
4148                  * @param Title $title
4149                  * @param bool|null $isKnown
4150                  */
4151                 Hooks::run( 'TitleIsAlwaysKnown', [ $this, &$isKnown ] );
4152
4153                 if ( !is_null( $isKnown ) ) {
4154                         return $isKnown;
4155                 }
4156
4157                 if ( $this->isExternal() ) {
4158                         return true; // any interwiki link might be viewable, for all we know
4159                 }
4160
4161                 $services = MediaWikiServices::getInstance();
4162                 switch ( $this->mNamespace ) {
4163                         case NS_MEDIA:
4164                         case NS_FILE:
4165                                 // file exists, possibly in a foreign repo
4166                                 return (bool)$services->getRepoGroup()->findFile( $this );
4167                         case NS_SPECIAL:
4168                                 // valid special page
4169                                 return $services->getSpecialPageFactory()->exists( $this->mDbkeyform );
4170                         case NS_MAIN:
4171                                 // selflink, possibly with fragment
4172                                 return $this->mDbkeyform == '';
4173                         case NS_MEDIAWIKI:
4174                                 // known system message
4175                                 return $this->hasSourceText() !== false;
4176                         default:
4177                                 return false;
4178                 }
4179         }
4180
4181         /**
4182          * Does this title refer to a page that can (or might) be meaningfully
4183          * viewed?  In particular, this function may be used to determine if
4184          * links to the title should be rendered as "bluelinks" (as opposed to
4185          * "redlinks" to non-existent pages).
4186          * Adding something else to this function will cause inconsistency
4187          * since LinkHolderArray calls isAlwaysKnown() and does its own
4188          * page existence check.
4189          *
4190          * @return bool
4191          */
4192         public function isKnown() {
4193                 return $this->isAlwaysKnown() || $this->exists();
4194         }
4195
4196         /**
4197          * Does this page have source text?
4198          *
4199          * @return bool
4200          */
4201         public function hasSourceText() {
4202                 if ( $this->exists() ) {
4203                         return true;
4204                 }
4205
4206                 if ( $this->mNamespace == NS_MEDIAWIKI ) {
4207                         // If the page doesn't exist but is a known system message, default
4208                         // message content will be displayed, same for language subpages-
4209                         // Use always content language to avoid loading hundreds of languages
4210                         // to get the link color.
4211                         $contLang = MediaWikiServices::getInstance()->getContentLanguage();
4212                         list( $name, ) = MessageCache::singleton()->figureMessage(
4213                                 $contLang->lcfirst( $this->getText() )
4214                         );
4215                         $message = wfMessage( $name )->inLanguage( $contLang )->useDatabase( false );
4216                         return $message->exists();
4217                 }
4218
4219                 return false;
4220         }
4221
4222         /**
4223          * Get the default (plain) message contents for an page that overrides an
4224          * interface message key.
4225          *
4226          * Primary use cases:
4227          *
4228          * - Article:
4229          *    - Show default when viewing the page. The Article::getSubstituteContent
4230          *      method displays the default message content, instead of the
4231          *      'noarticletext' placeholder message normally used.
4232          *
4233          * - EditPage:
4234          *    - Title of edit page. When creating an interface message override,
4235          *      the editor is told they are "Editing the page", instead of
4236          *      "Creating the page". (EditPage::setHeaders)
4237          *    - Edit notice. The 'translateinterface' edit notice is shown when creating
4238          *      or editing a an interface message override. (EditPage::showIntro)
4239          *    - Opening the editor. The contents of the localisation message are used
4240          *      as contents of the editor when creating a new page in the MediaWiki
4241          *      namespace. This simplifies the process for editors when "changing"
4242          *      an interface message by creating an override. (EditPage::getContentObject)
4243          *    - Showing a diff. The left-hand side of a diff when an editor is
4244          *      previewing their changes before saving the creation of a page in the
4245          *      MediaWiki namespace. (EditPage::showDiff)
4246          *    - Disallowing a save. When attempting to create a a MediaWiki-namespace
4247          *      page with the proposed content matching the interface message default,
4248          *      the save is rejected, the same way we disallow blank pages from being
4249          *      created. (EditPage::internalAttemptSave)
4250          *
4251          * - ApiEditPage:
4252          *    - Default content, when using the 'prepend' or 'append' feature.
4253          *
4254          * - SkinTemplate:
4255          *    - Label the create action as "Edit", if the page can be an override.
4256          *
4257          * @return string|bool
4258          */
4259         public function getDefaultMessageText() {
4260                 if ( $this->mNamespace != NS_MEDIAWIKI ) { // Just in case
4261                         return false;
4262                 }
4263
4264                 list( $name, $lang ) = MessageCache::singleton()->figureMessage(
4265                         MediaWikiServices::getInstance()->getContentLanguage()->lcfirst( $this->getText() )
4266                 );
4267                 $message = wfMessage( $name )->inLanguage( $lang )->useDatabase( false );
4268
4269                 if ( $message->exists() ) {
4270                         return $message->plain();
4271                 } else {
4272                         return false;
4273                 }
4274         }
4275
4276         /**
4277          * Updates page_touched for this page; called from LinksUpdate.php
4278          *
4279          * @param string|null $purgeTime [optional] TS_MW timestamp
4280          * @return bool True if the update succeeded
4281          */
4282         public function invalidateCache( $purgeTime = null ) {
4283                 if ( wfReadOnly() ) {
4284                         return false;
4285                 } elseif ( $this->mArticleID === 0 ) {
4286                         return true; // avoid gap locking if we know it's not there
4287                 }
4288
4289                 $dbw = wfGetDB( DB_MASTER );
4290                 $dbw->onTransactionPreCommitOrIdle(
4291                         function () use ( $dbw ) {
4292                                 ResourceLoaderWikiModule::invalidateModuleCache(
4293                                         $this, null, null, $dbw->getDomainID() );
4294                         },
4295                         __METHOD__
4296                 );
4297
4298                 $conds = $this->pageCond();
4299                 DeferredUpdates::addUpdate(
4300                         new AutoCommitUpdate(
4301                                 $dbw,
4302                                 __METHOD__,
4303                                 function ( IDatabase $dbw, $fname ) use ( $conds, $purgeTime ) {
4304                                         $dbTimestamp = $dbw->timestamp( $purgeTime ?: time() );
4305                                         $dbw->update(
4306                                                 'page',
4307                                                 [ 'page_touched' => $dbTimestamp ],
4308                                                 $conds + [ 'page_touched < ' . $dbw->addQuotes( $dbTimestamp ) ],
4309                                                 $fname
4310                                         );
4311                                         MediaWikiServices::getInstance()->getLinkCache()->invalidateTitle( $this );
4312                                 }
4313                         ),
4314                         DeferredUpdates::PRESEND
4315                 );
4316
4317                 return true;
4318         }
4319
4320         /**
4321          * Update page_touched timestamps and send CDN purge messages for
4322          * pages linking to this title. May be sent to the job queue depending
4323          * on the number of links. Typically called on create and delete.
4324          */
4325         public function touchLinks() {
4326                 DeferredUpdates::addUpdate( new HTMLCacheUpdate( $this, 'pagelinks', 'page-touch' ) );
4327                 if ( $this->mNamespace == NS_CATEGORY ) {
4328                         DeferredUpdates::addUpdate(
4329                                 new HTMLCacheUpdate( $this, 'categorylinks', 'category-touch' )
4330                         );
4331                 }
4332         }
4333
4334         /**
4335          * Get the last touched timestamp
4336          *
4337          * @param IDatabase|null $db
4338          * @return string|false Last-touched timestamp
4339          */
4340         public function getTouched( $db = null ) {
4341                 if ( $db === null ) {
4342                         $db = wfGetDB( DB_REPLICA );
4343                 }
4344                 $touched = $db->selectField( 'page', 'page_touched', $this->pageCond(), __METHOD__ );
4345                 return $touched;
4346         }
4347
4348         /**
4349          * Get the timestamp when this page was updated since the user last saw it.
4350          *
4351          * @param User|null $user
4352          * @return string|bool|null String timestamp, false if not watched, null if nothing is unseen
4353          */
4354         public function getNotificationTimestamp( $user = null ) {
4355                 global $wgUser;
4356
4357                 // Assume current user if none given
4358                 if ( !$user ) {
4359                         $user = $wgUser;
4360                 }
4361                 // Check cache first
4362                 $uid = $user->getId();
4363                 if ( !$uid ) {
4364                         return false;
4365                 }
4366                 // avoid isset here, as it'll return false for null entries
4367                 if ( array_key_exists( $uid, $this->mNotificationTimestamp ) ) {
4368                         return $this->mNotificationTimestamp[$uid];
4369                 }
4370                 // Don't cache too much!
4371                 if ( count( $this->mNotificationTimestamp ) >= self::CACHE_MAX ) {
4372                         $this->mNotificationTimestamp = [];
4373                 }
4374
4375                 $store = MediaWikiServices::getInstance()->getWatchedItemStore();
4376                 $watchedItem = $store->getWatchedItem( $user, $this );
4377                 if ( $watchedItem ) {
4378                         $this->mNotificationTimestamp[$uid] = $watchedItem->getNotificationTimestamp();
4379                 } else {
4380                         $this->mNotificationTimestamp[$uid] = false;
4381                 }
4382
4383                 return $this->mNotificationTimestamp[$uid];
4384         }
4385
4386         /**
4387          * Generate strings used for xml 'id' names in monobook tabs
4388          *
4389          * @param string $prepend Defaults to 'nstab-'
4390          * @return string XML 'id' name
4391          */
4392         public function getNamespaceKey( $prepend = 'nstab-' ) {
4393                 // Gets the subject namespace of this title
4394                 $nsInfo = MediaWikiServices::getInstance()->getNamespaceInfo();
4395                 $subjectNS = $nsInfo->getSubject( $this->mNamespace );
4396                 // Prefer canonical namespace name for HTML IDs
4397                 $namespaceKey = $nsInfo->getCanonicalName( $subjectNS );
4398                 if ( $namespaceKey === false ) {
4399                         // Fallback to localised text
4400                         $namespaceKey = $this->getSubjectNsText();
4401                 }
4402                 // Makes namespace key lowercase
4403                 $namespaceKey = MediaWikiServices::getInstance()->getContentLanguage()->lc( $namespaceKey );
4404                 // Uses main
4405                 if ( $namespaceKey == '' ) {
4406                         $namespaceKey = 'main';
4407                 }
4408                 // Changes file to image for backwards compatibility
4409                 if ( $namespaceKey == 'file' ) {
4410                         $namespaceKey = 'image';
4411                 }
4412                 return $prepend . $namespaceKey;
4413         }
4414
4415         /**
4416          * Get all extant redirects to this Title
4417          *
4418          * @param int|null $ns Single namespace to consider; null to consider all namespaces
4419          * @return Title[] Array of Title redirects to this title
4420          */
4421         public function getRedirectsHere( $ns = null ) {
4422                 $redirs = [];
4423
4424                 $dbr = wfGetDB( DB_REPLICA );
4425                 $where = [
4426                         'rd_namespace' => $this->mNamespace,
4427                         'rd_title' => $this->mDbkeyform,
4428                         'rd_from = page_id'
4429                 ];
4430                 if ( $this->isExternal() ) {
4431                         $where['rd_interwiki'] = $this->mInterwiki;
4432                 } else {
4433                         $where[] = 'rd_interwiki = ' . $dbr->addQuotes( '' ) . ' OR rd_interwiki IS NULL';
4434                 }
4435                 if ( !is_null( $ns ) ) {
4436                         $where['page_namespace'] = $ns;
4437                 }
4438
4439                 $res = $dbr->select(
4440                         [ 'redirect', 'page' ],
4441                         [ 'page_namespace', 'page_title' ],
4442                         $where,
4443                         __METHOD__
4444                 );
4445
4446                 foreach ( $res as $row ) {
4447                         $redirs[] = self::newFromRow( $row );
4448                 }
4449                 return $redirs;
4450         }
4451
4452         /**
4453          * Check if this Title is a valid redirect target
4454          *
4455          * @return bool
4456          */
4457         public function isValidRedirectTarget() {
4458                 global $wgInvalidRedirectTargets;
4459
4460                 if ( $this->isSpecialPage() ) {
4461                         // invalid redirect targets are stored in a global array, but explicitly disallow Userlogout here
4462                         if ( $this->isSpecial( 'Userlogout' ) ) {
4463                                 return false;
4464                         }
4465
4466                         foreach ( $wgInvalidRedirectTargets as $target ) {
4467                                 if ( $this->isSpecial( $target ) ) {
4468                                         return false;
4469                                 }
4470                         }
4471                 }
4472
4473                 return true;
4474         }
4475
4476         /**
4477          * Get a backlink cache object
4478          *
4479          * @return BacklinkCache
4480          */
4481         public function getBacklinkCache() {
4482                 return BacklinkCache::get( $this );
4483         }
4484
4485         /**
4486          * Whether the magic words __INDEX__ and __NOINDEX__ function for this page.
4487          *
4488          * @return bool
4489          */
4490         public function canUseNoindex() {
4491                 global $wgExemptFromUserRobotsControl;
4492
4493                 $bannedNamespaces = $wgExemptFromUserRobotsControl ??
4494                         MediaWikiServices::getInstance()->getNamespaceInfo()->getContentNamespaces();
4495
4496                 return !in_array( $this->mNamespace, $bannedNamespaces );
4497         }
4498
4499         /**
4500          * Returns the raw sort key to be used for categories, with the specified
4501          * prefix.  This will be fed to Collation::getSortKey() to get a
4502          * binary sortkey that can be used for actual sorting.
4503          *
4504          * @param string $prefix The prefix to be used, specified using
4505          *   {{defaultsort:}} or like [[Category:Foo|prefix]].  Empty for no
4506          *   prefix.
4507          * @return string
4508          */
4509         public function getCategorySortkey( $prefix = '' ) {
4510                 $unprefixed = $this->getText();
4511
4512                 // Anything that uses this hook should only depend
4513                 // on the Title object passed in, and should probably
4514                 // tell the users to run updateCollations.php --force
4515                 // in order to re-sort existing category relations.
4516                 Hooks::run( 'GetDefaultSortkey', [ $this, &$unprefixed ] );
4517                 if ( $prefix !== '' ) {
4518                         # Separate with a line feed, so the unprefixed part is only used as
4519                         # a tiebreaker when two pages have the exact same prefix.
4520                         # In UCA, tab is the only character that can sort above LF
4521                         # so we strip both of them from the original prefix.
4522                         $prefix = strtr( $prefix, "\n\t", '  ' );
4523                         return "$prefix\n$unprefixed";
4524                 }
4525                 return $unprefixed;
4526         }
4527
4528         /**
4529          * Returns the page language code saved in the database, if $wgPageLanguageUseDB is set
4530          * to true in LocalSettings.php, otherwise returns false. If there is no language saved in
4531          * the db, it will return NULL.
4532          *
4533          * @return string|null|bool
4534          */
4535         private function getDbPageLanguageCode() {
4536                 global $wgPageLanguageUseDB;
4537
4538                 // check, if the page language could be saved in the database, and if so and
4539                 // the value is not requested already, lookup the page language using LinkCache
4540                 if ( $wgPageLanguageUseDB && $this->mDbPageLanguage === false ) {
4541                         $linkCache = MediaWikiServices::getInstance()->getLinkCache();
4542                         $linkCache->addLinkObj( $this );
4543                         $this->mDbPageLanguage = $linkCache->getGoodLinkFieldObj( $this, 'lang' );
4544                 }
4545
4546                 return $this->mDbPageLanguage;
4547         }
4548
4549         /**
4550          * Get the language in which the content of this page is written in
4551          * wikitext. Defaults to content language, but in certain cases it can be
4552          * e.g. $wgLang (such as special pages, which are in the user language).
4553          *
4554          * @since 1.18
4555          * @return Language
4556          */
4557         public function getPageLanguage() {
4558                 global $wgLang, $wgLanguageCode;
4559                 if ( $this->isSpecialPage() ) {
4560                         // special pages are in the user language
4561                         return $wgLang;
4562                 }
4563
4564                 // Checking if DB language is set
4565                 $dbPageLanguage = $this->getDbPageLanguageCode();
4566                 if ( $dbPageLanguage ) {
4567                         return wfGetLangObj( $dbPageLanguage );
4568                 }
4569
4570                 if ( !$this->mPageLanguage || $this->mPageLanguage[1] !== $wgLanguageCode ) {
4571                         // Note that this may depend on user settings, so the cache should
4572                         // be only per-request.
4573                         // NOTE: ContentHandler::getPageLanguage() may need to load the
4574                         // content to determine the page language!
4575                         // Checking $wgLanguageCode hasn't changed for the benefit of unit
4576                         // tests.
4577                         $contentHandler = ContentHandler::getForTitle( $this );
4578                         $langObj = $contentHandler->getPageLanguage( $this );
4579                         $this->mPageLanguage = [ $langObj->getCode(), $wgLanguageCode ];
4580                 } else {
4581                         $langObj = Language::factory( $this->mPageLanguage[0] );
4582                 }
4583
4584                 return $langObj;
4585         }
4586
4587         /**
4588          * Get the language in which the content of this page is written when
4589          * viewed by user. Defaults to content language, but in certain cases it can be
4590          * e.g. $wgLang (such as special pages, which are in the user language).
4591          *
4592          * @since 1.20
4593          * @return Language
4594          */
4595         public function getPageViewLanguage() {
4596                 global $wgLang;
4597
4598                 if ( $this->isSpecialPage() ) {
4599                         // If the user chooses a variant, the content is actually
4600                         // in a language whose code is the variant code.
4601                         $variant = $wgLang->getPreferredVariant();
4602                         if ( $wgLang->getCode() !== $variant ) {
4603                                 return Language::factory( $variant );
4604                         }
4605
4606                         return $wgLang;
4607                 }
4608
4609                 // Checking if DB language is set
4610                 $dbPageLanguage = $this->getDbPageLanguageCode();
4611                 if ( $dbPageLanguage ) {
4612                         $pageLang = wfGetLangObj( $dbPageLanguage );
4613                         $variant = $pageLang->getPreferredVariant();
4614                         if ( $pageLang->getCode() !== $variant ) {
4615                                 $pageLang = Language::factory( $variant );
4616                         }
4617
4618                         return $pageLang;
4619                 }
4620
4621                 // @note Can't be cached persistently, depends on user settings.
4622                 // @note ContentHandler::getPageViewLanguage() may need to load the
4623                 //   content to determine the page language!
4624                 $contentHandler = ContentHandler::getForTitle( $this );
4625                 $pageLang = $contentHandler->getPageViewLanguage( $this );
4626                 return $pageLang;
4627         }
4628
4629         /**
4630          * Get a list of rendered edit notices for this page.
4631          *
4632          * Array is keyed by the original message key, and values are rendered using parseAsBlock, so
4633          * they will already be wrapped in paragraphs.
4634          *
4635          * @since 1.21
4636          * @param int $oldid Revision ID that's being edited
4637          * @return array
4638          */
4639         public function getEditNotices( $oldid = 0 ) {
4640                 $notices = [];
4641
4642                 // Optional notice for the entire namespace
4643                 $editnotice_ns = 'editnotice-' . $this->mNamespace;
4644                 $msg = wfMessage( $editnotice_ns );
4645                 if ( $msg->exists() ) {
4646                         $html = $msg->parseAsBlock();
4647                         // Edit notices may have complex logic, but output nothing (T91715)
4648                         if ( trim( $html ) !== '' ) {
4649                                 $notices[$editnotice_ns] = Html::rawElement(
4650                                         'div',
4651                                         [ 'class' => [
4652                                                 'mw-editnotice',
4653                                                 'mw-editnotice-namespace',
4654                                                 Sanitizer::escapeClass( "mw-$editnotice_ns" )
4655                                         ] ],
4656                                         $html
4657                                 );
4658                         }
4659                 }
4660
4661                 if (
4662                         MediaWikiServices::getInstance()->getNamespaceInfo()->
4663                                 hasSubpages( $this->mNamespace )
4664                 ) {
4665                         // Optional notice for page itself and any parent page
4666                         $editnotice_base = $editnotice_ns;
4667                         foreach ( explode( '/', $this->mDbkeyform ) as $part ) {
4668                                 $editnotice_base .= '-' . $part;
4669                                 $msg = wfMessage( $editnotice_base );
4670                                 if ( $msg->exists() ) {
4671                                         $html = $msg->parseAsBlock();
4672                                         if ( trim( $html ) !== '' ) {
4673                                                 $notices[$editnotice_base] = Html::rawElement(
4674                                                         'div',
4675                                                         [ 'class' => [
4676                                                                 'mw-editnotice',
4677                                                                 'mw-editnotice-base',
4678                                                                 Sanitizer::escapeClass( "mw-$editnotice_base" )
4679                                                         ] ],
4680                                                         $html
4681                                                 );
4682                                         }
4683                                 }
4684                         }
4685                 } else {
4686                         // Even if there are no subpages in namespace, we still don't want "/" in MediaWiki message keys
4687                         $editnoticeText = $editnotice_ns . '-' . strtr( $this->mDbkeyform, '/', '-' );
4688                         $msg = wfMessage( $editnoticeText );
4689                         if ( $msg->exists() ) {
4690                                 $html = $msg->parseAsBlock();
4691                                 if ( trim( $html ) !== '' ) {
4692                                         $notices[$editnoticeText] = Html::rawElement(
4693                                                 'div',
4694                                                 [ 'class' => [
4695                                                         'mw-editnotice',
4696                                                         'mw-editnotice-page',
4697                                                         Sanitizer::escapeClass( "mw-$editnoticeText" )
4698                                                 ] ],
4699                                                 $html
4700                                         );
4701                                 }
4702                         }
4703                 }
4704
4705                 Hooks::run( 'TitleGetEditNotices', [ $this, $oldid, &$notices ] );
4706                 return $notices;
4707         }
4708
4709         /**
4710          * @return array
4711          */
4712         public function __sleep() {
4713                 return [
4714                         'mNamespace',
4715                         'mDbkeyform',
4716                         'mFragment',
4717                         'mInterwiki',
4718                         'mLocalInterwiki',
4719                         'mUserCaseDBKey',
4720                         'mDefaultNamespace',
4721                 ];
4722         }
4723
4724         public function __wakeup() {
4725                 $this->mArticleID = ( $this->mNamespace >= 0 ) ? -1 : 0;
4726                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
4727                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
4728         }
4729
4730 }