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 and inject it into link cache.
  56          * @deprecated since 1.34, use Title::READ_LATEST instead.
  57          */
  58         const GAID_FOR_UPDATE = 512;
  59
  60         /**
  61          * Flag for use with factory methods like newFromLinkTarget() that have
  62          * a $forceClone parameter. If set, the method must return a new instance.
  63          * Without this flag, some factory methods may return existing instances.
  64          *
  65          * @since 1.33
  66          */
  67         const NEW_CLONE = 'clone';
  68
  69         /**
  70          * @name Private member variables
  71          * Please use the accessor functions instead.
  72          * @private
  73          */
  74         // @{
  75
  76         /** @var string Text form (spaces not underscores) of the main part */
  77         public $mTextform = '';
  78         /** @var string URL-encoded form of the main part */
  79         public $mUrlform = '';
  80         /** @var string Main part with underscores */
  81         public $mDbkeyform = '';
  82         /** @var string Database key with the initial letter in the case specified by the user */
  83         protected $mUserCaseDBKey;
  84         /** @var int Namespace index, i.e. one of the NS_xxxx constants */
  85         public $mNamespace = NS_MAIN;
  86         /** @var string Interwiki prefix */
  87         public $mInterwiki = '';
  88         /** @var bool Was this Title created from a string with a local interwiki prefix? */
  89         private $mLocalInterwiki = false;
  90         /** @var string Title fragment (i.e. the bit after the #) */
  91         public $mFragment = '';
  92
  93         /** @var int Article ID, fetched from the link cache on demand */
  94         public $mArticleID = -1;
  95
  96         /** @var bool|int ID of most recent revision */
  97         protected $mLatestID = false;
  98
  99         /**
 100          * @var bool|string ID of the page's content model, i.e. one of the
 101          *   CONTENT_MODEL_XXX constants
 102          */
 103         private $mContentModel = false;
 104
 105         /**
 106          * @var bool If a content model was forced via setContentModel()
 107          *   this will be true to avoid having other code paths reset it
 108          */
 109         private $mForcedContentModel = false;
 110
 111         /** @var int Estimated number of revisions; null of not loaded */
 112         private $mEstimateRevisions;
 113
 114         /** @var array Array of groups allowed to edit this article */
 115         public $mRestrictions = [];
 116
 117         /**
 118          * @var string|bool Comma-separated set of permission keys
 119          * indicating who can move or edit the page from the page table, (pre 1.10) rows.
 120          * Edit and move sections are separated by a colon
 121          * Example: "edit=autoconfirmed,sysop:move=sysop"
 122          */
 123         protected $mOldRestrictions = false;
 124
 125         /** @var bool Cascade restrictions on this page to included templates and images? */
 126         public $mCascadeRestriction;
 127
 128         /** Caching the results of getCascadeProtectionSources */
 129         public $mCascadingRestrictions;
 130
 131         /** @var array When do the restrictions on this page expire? */
 132         protected $mRestrictionsExpiry = [];
 133
 134         /** @var bool Are cascading restrictions in effect on this page? */
 135         protected $mHasCascadingRestrictions;
 136
 137         /** @var array Where are the cascading restrictions coming from on this page? */
 138         public $mCascadeSources;
 139
 140         /** @var bool Boolean for initialisation on demand */
 141         public $mRestrictionsLoaded = false;
 142
 143         /**
 144          * Text form including namespace/interwiki, initialised on demand
 145          *
 146          * Only public to share cache with TitleFormatter
 147          *
 148          * @private
 149          * @var string|null
 150          */
 151         public $prefixedText = null;
 152
 153         /** @var mixed Cached value for getTitleProtection (create protection) */
 154         public $mTitleProtection;
 155
 156         /**
 157          * @var int Namespace index when there is no namespace. Don't change the
 158          *   following default, NS_MAIN is hardcoded in several places. See T2696.
 159          *   Zero except in {{transclusion}} tags.
 160          */
 161         public $mDefaultNamespace = NS_MAIN;
 162
 163         /** @var int The page length, 0 for special pages */
 164         protected $mLength = -1;
 165
 166         /** @var null Is the article at this title a redirect? */
 167         public $mRedirect = null;
 168
 169         /** @var array Associative array of user ID -> timestamp/false */
 170         private $mNotificationTimestamp = [];
 171
 172         /** @var bool Whether a page has any subpages */
 173         private $mHasSubpages;
 174
 175         /** @var array|null The (string) language code of the page's language and content code. */
 176         private $mPageLanguage;
 177
 178         /** @var string|bool|null The page language code from the database, null if not saved in
 179          * the database or false if not loaded, yet.
 180          */
 181         private $mDbPageLanguage = false;
 182
 183         /** @var TitleValue|null A corresponding TitleValue object */
 184         private $mTitleValue = null;
 185
 186         /** @var bool|null Would deleting this page be a big deletion? */
 187         private $mIsBigDeletion = null;
 188         // @}
 189
 190         /**
 191          * B/C kludge: provide a TitleParser for use by Title.
 192          * Ideally, Title would have no methods that need this.
 193          * Avoid usage of this singleton by using TitleValue
 194          * and the associated services when possible.
 195          *
 196          * @return TitleFormatter
 197          */
 198         private static function getTitleFormatter() {
 199                 return MediaWikiServices::getInstance()->getTitleFormatter();
 200         }
 201
 202         /**
 203          * B/C kludge: provide an InterwikiLookup for use by Title.
 204          * Ideally, Title would have no methods that need this.
 205          * Avoid usage of this singleton by using TitleValue
 206          * and the associated services when possible.
 207          *
 208          * @return InterwikiLookup
 209          */
 210         private static function getInterwikiLookup() {
 211                 return MediaWikiServices::getInstance()->getInterwikiLookup();
 212         }
 213
 214         /**
 215          * @protected
 216          */
 217         function __construct() {
 218         }
 219
 220         /**
 221          * Create a new Title from a prefixed DB key
 222          *
 223          * @param string $key The database key, which has underscores
 224          *      instead of spaces, possibly including namespace and
 225          *      interwiki prefixes
 226          * @return Title|null Title, or null on an error
 227          */
 228         public static function newFromDBkey( $key ) {
 229                 $t = new self();
 230                 $t->mDbkeyform = $key;
 231
 232                 try {
 233                         $t->secureAndSplit();
 234                         return $t;
 235                 } catch ( MalformedTitleException $ex ) {
 236                         return null;
 237                 }
 238         }
 239
 240         /**
 241          * Returns a Title given a TitleValue.
 242          * If the given TitleValue is already a Title instance, that instance is returned,
 243          * unless $forceClone is "clone". If $forceClone is "clone" and the given TitleValue
 244          * is already a Title instance, that instance is copied using the clone operator.
 245          *
 246          * @deprecated since 1.34, use newFromLinkTarget or castFromLinkTarget
 247          *
 248          * @param TitleValue $titleValue Assumed to be safe.
 249          * @param string $forceClone set to NEW_CLONE to ensure a fresh instance is returned.
 250          *
 251          * @return Title
 252          */
 253         public static function newFromTitleValue( TitleValue $titleValue, $forceClone = '' ) {
 254                 return self::newFromLinkTarget( $titleValue, $forceClone );
 255         }
 256
 257         /**
 258          * Returns a Title given a LinkTarget.
 259          * If the given LinkTarget is already a Title instance, that instance is returned,
 260          * unless $forceClone is "clone". If $forceClone is "clone" and the given LinkTarget
 261          * is already a Title instance, that instance is copied using the clone operator.
 262          *
 263          * @param LinkTarget $linkTarget Assumed to be safe.
 264          * @param string $forceClone set to NEW_CLONE to ensure a fresh instance is returned.
 265          *
 266          * @return Title
 267          */
 268         public static function newFromLinkTarget( LinkTarget $linkTarget, $forceClone = '' ) {
 269                 if ( $linkTarget instanceof Title ) {
 270                         // Special case if it's already a Title object
 271                         if ( $forceClone === self::NEW_CLONE ) {
 272                                 return clone $linkTarget;
 273                         } else {
 274                                 return $linkTarget;
 275                         }
 276                 }
 277                 return self::makeTitle(
 278                         $linkTarget->getNamespace(),
 279                         $linkTarget->getText(),
 280                         $linkTarget->getFragment(),
 281                         $linkTarget->getInterwiki()
 282                 );
 283         }
 284
 285         /**
 286          * Same as newFromLinkTarget, but if passed null, returns null.
 287          *
 288          * @param LinkTarget|null $linkTarget Assumed to be safe (if not null).
 289          *
 290          * @return Title|null
 291          */
 292         public static function castFromLinkTarget( $linkTarget ) {
 293                 return $linkTarget ? self::newFromLinkTarget( $linkTarget ) : null;
 294         }
 295
 296         /**
 297          * Create a new Title from text, such as what one would find in a link. De-
 298          * codes any HTML entities in the text.
 299          *
 300          * Title objects returned by this method are guaranteed to be valid, and
 301          * thus return true from the isValid() method.
 302          *
 303          * @note The Title instance returned by this method is not guaranteed to be a fresh instance.
 304          * It may instead be a cached instance created previously, with references to it remaining
 305          * elsewhere.
 306          *
 307          * @param string|int|null $text The link text; spaces, prefixes, and an
 308          *   initial ':' indicating the main namespace are accepted.
 309          * @param int $defaultNamespace The namespace to use if none is specified
 310          *   by a prefix.  If you want to force a specific namespace even if
 311          *   $text might begin with a namespace prefix, use makeTitle() or
 312          *   makeTitleSafe().
 313          * @throws InvalidArgumentException
 314          * @return Title|null Title or null on an error.
 315          */
 316         public static function newFromText( $text, $defaultNamespace = NS_MAIN ) {
 317                 // DWIM: Integers can be passed in here when page titles are used as array keys.
 318                 if ( $text !== null && !is_string( $text ) && !is_int( $text ) ) {
 319                         throw new InvalidArgumentException( '$text must be a string.' );
 320                 }
 321                 if ( $text === null ) {
 322                         return null;
 323                 }
 324
 325                 try {
 326                         return self::newFromTextThrow( (string)$text, $defaultNamespace );
 327                 } catch ( MalformedTitleException $ex ) {
 328                         return null;
 329                 }
 330         }
 331
 332         /**
 333          * Like Title::newFromText(), but throws MalformedTitleException when the title is invalid,
 334          * rather than returning null.
 335          *
 336          * The exception subclasses encode detailed information about why the title is invalid.
 337          *
 338          * Title objects returned by this method are guaranteed to be valid, and
 339          * thus return true from the isValid() method.
 340          *
 341          * @note The Title instance returned by this method is not guaranteed to be a fresh instance.
 342          * It may instead be a cached instance created previously, with references to it remaining
 343          * elsewhere.
 344          *
 345          * @see Title::newFromText
 346          *
 347          * @since 1.25
 348          * @param string $text Title text to check
 349          * @param int $defaultNamespace
 350          * @throws MalformedTitleException If the title is invalid
 351          * @return Title
 352          */
 353         public static function newFromTextThrow( $text, $defaultNamespace = NS_MAIN ) {
 354                 if ( is_object( $text ) ) {
 355                         throw new MWException( '$text must be a string, given an object' );
 356                 } elseif ( $text === null ) {
 357                         // Legacy code relies on MalformedTitleException being thrown in this case
 358                         // (happens when URL with no title in it is parsed). TODO fix
 359                         throw new MalformedTitleException( 'title-invalid-empty' );
 360                 }
 361
 362                 $titleCache = self::getTitleCache();
 363
 364                 // Wiki pages often contain multiple links to the same page.
 365                 // Title normalization and parsing can become expensive on pages with many
 366                 // links, so we can save a little time by caching them.
 367                 // In theory these are value objects and won't get changed...
 368                 if ( $defaultNamespace == NS_MAIN ) {
 369                         $t = $titleCache->get( $text );
 370                         if ( $t ) {
 371                                 return $t;
 372                         }
 373                 }
 374
 375                 // Convert things like &eacute; &#257; or &#x3017; into normalized (T16952) text
 376                 $filteredText = Sanitizer::decodeCharReferencesAndNormalize( $text );
 377
 378                 $t = new Title();
 379                 $t->mDbkeyform = strtr( $filteredText, ' ', '_' );
 380                 $t->mDefaultNamespace = (int)$defaultNamespace;
 381
 382                 $t->secureAndSplit();
 383                 if ( $defaultNamespace == NS_MAIN ) {
 384                         $titleCache->set( $text, $t );
 385                 }
 386                 return $t;
 387         }
 388
 389         /**
 390          * THIS IS NOT THE FUNCTION YOU WANT. Use Title::newFromText().
 391          *
 392          * Example of wrong and broken code:
 393          * $title = Title::newFromURL( $wgRequest->getVal( 'title' ) );
 394          *
 395          * Example of right code:
 396          * $title = Title::newFromText( $wgRequest->getVal( 'title' ) );
 397          *
 398          * Create a new Title from URL-encoded text. Ensures that
 399          * the given title's length does not exceed the maximum.
 400          *
 401          * @param string $url The title, as might be taken from a URL
 402          * @return Title|null The new object, or null on an error
 403          */
 404         public static function newFromURL( $url ) {
 405                 $t = new Title();
 406
 407                 # For compatibility with old buggy URLs. "+" is usually not valid in titles,
 408                 # but some URLs used it as a space replacement and they still come
 409                 # from some external search tools.
 410                 if ( strpos( self::legalChars(), '+' ) === false ) {
 411                         $url = strtr( $url, '+', ' ' );
 412                 }
 413
 414                 $t->mDbkeyform = strtr( $url, ' ', '_' );
 415
 416                 try {
 417                         $t->secureAndSplit();
 418                         return $t;
 419                 } catch ( MalformedTitleException $ex ) {
 420                         return null;
 421                 }
 422         }
 423
 424         /**
 425          * @return MapCacheLRU
 426          */
 427         private static function getTitleCache() {
 428                 if ( self::$titleCache === null ) {
 429                         self::$titleCache = new MapCacheLRU( self::CACHE_MAX );
 430                 }
 431                 return self::$titleCache;
 432         }
 433
 434         /**
 435          * Returns a list of fields that are to be selected for initializing Title
 436          * objects or LinkCache entries. Uses $wgContentHandlerUseDB to determine
 437          * whether to include page_content_model.
 438          *
 439          * @return array
 440          */
 441         protected static function getSelectFields() {
 442                 global $wgContentHandlerUseDB, $wgPageLanguageUseDB;
 443
 444                 $fields = [
 445                         'page_namespace', 'page_title', 'page_id',
 446                         'page_len', 'page_is_redirect', 'page_latest',
 447                 ];
 448
 449                 if ( $wgContentHandlerUseDB ) {
 450                         $fields[] = 'page_content_model';
 451                 }
 452
 453                 if ( $wgPageLanguageUseDB ) {
 454                         $fields[] = 'page_lang';
 455                 }
 456
 457                 return $fields;
 458         }
 459
 460         /**
 461          * Create a new Title from an article ID
 462          *
 463          * @param int $id The page_id corresponding to the Title to create
 464          * @param int $flags Bitfield of class READ_* constants
 465          * @return Title|null The new object, or null on an error
 466          */
 467         public static function newFromID( $id, $flags = 0 ) {
 468                 $flags |= ( $flags & self::GAID_FOR_UPDATE ) ? self::READ_LATEST : 0; // b/c
 469                 list( $index, $options ) = DBAccessObjectUtils::getDBOptions( $flags );
 470                 $row = wfGetDB( $index )->selectRow(
 471                         'page',
 472                         self::getSelectFields(),
 473                         [ 'page_id' => $id ],
 474                         __METHOD__,
 475                         $options
 476                 );
 477                 if ( $row !== false ) {
 478                         $title = self::newFromRow( $row );
 479                 } else {
 480                         $title = null;
 481                 }
 482
 483                 return $title;
 484         }
 485
 486         /**
 487          * Make an array of titles from an array of IDs
 488          *
 489          * @param int[] $ids Array of IDs
 490          * @return Title[] Array of Titles
 491          */
 492         public static function newFromIDs( $ids ) {
 493                 if ( !count( $ids ) ) {
 494                         return [];
 495                 }
 496                 $dbr = wfGetDB( DB_REPLICA );
 497
 498                 $res = $dbr->select(
 499                         'page',
 500                         self::getSelectFields(),
 501                         [ 'page_id' => $ids ],
 502                         __METHOD__
 503                 );
 504
 505                 $titles = [];
 506                 foreach ( $res as $row ) {
 507                         $titles[] = self::newFromRow( $row );
 508                 }
 509                 return $titles;
 510         }
 511
 512         /**
 513          * Make a Title object from a DB row
 514          *
 515          * @param stdClass $row Object database row (needs at least page_title,page_namespace)
 516          * @return Title Corresponding Title
 517          */
 518         public static function newFromRow( $row ) {
 519                 $t = self::makeTitle( $row->page_namespace, $row->page_title );
 520                 $t->loadFromRow( $row );
 521                 return $t;
 522         }
 523
 524         /**
 525          * Load Title object fields from a DB row.
 526          * If false is given, the title will be treated as non-existing.
 527          *
 528          * @param stdClass|bool $row Database row
 529          */
 530         public function loadFromRow( $row ) {
 531                 if ( $row ) { // page found
 532                         if ( isset( $row->page_id ) ) {
 533                                 $this->mArticleID = (int)$row->page_id;
 534                         }
 535                         if ( isset( $row->page_len ) ) {
 536                                 $this->mLength = (int)$row->page_len;
 537                         }
 538                         if ( isset( $row->page_is_redirect ) ) {
 539                                 $this->mRedirect = (bool)$row->page_is_redirect;
 540                         }
 541                         if ( isset( $row->page_latest ) ) {
 542                                 $this->mLatestID = (int)$row->page_latest;
 543                         }
 544                         if ( isset( $row->page_content_model ) ) {
 545                                 $this->lazyFillContentModel( $row->page_content_model );
 546                         } else {
 547                                 $this->lazyFillContentModel( false ); // lazily-load getContentModel()
 548                         }
 549                         if ( isset( $row->page_lang ) ) {
 550                                 $this->mDbPageLanguage = (string)$row->page_lang;
 551                         }
 552                         if ( isset( $row->page_restrictions ) ) {
 553                                 $this->mOldRestrictions = $row->page_restrictions;
 554                         }
 555                 } else { // page not found
 556                         $this->mArticleID = 0;
 557                         $this->mLength = 0;
 558                         $this->mRedirect = false;
 559                         $this->mLatestID = 0;
 560                         $this->lazyFillContentModel( false ); // lazily-load getContentModel()
 561                 }
 562         }
 563
 564         /**
 565          * Create a new Title from a namespace index and a DB key.
 566          *
 567          * It's assumed that $ns and $title are safe, for instance when
 568          * they came directly from the database or a special page name,
 569          * not from user input.
 570          *
 571          * No validation is applied. For convenience, spaces are normalized
 572          * to underscores, so that e.g. user_text fields can be used directly.
 573          *
 574          * @note This method may return Title objects that are "invalid"
 575          * according to the isValid() method. This is usually caused by
 576          * configuration changes: e.g. a namespace that was once defined is
 577          * no longer configured, or a character that was once allowed in
 578          * titles is now forbidden.
 579          *
 580          * @param int $ns The namespace of the article
 581          * @param string $title The unprefixed database key form
 582          * @param string $fragment The link fragment (after the "#")
 583          * @param string $interwiki The interwiki prefix
 584          * @return Title The new object
 585          */
 586         public static function makeTitle( $ns, $title, $fragment = '', $interwiki = '' ) {
 587                 $t = new Title();
 588                 $t->mInterwiki = $interwiki;
 589                 $t->mFragment = $fragment;
 590                 $t->mNamespace = $ns = (int)$ns;
 591                 $t->mDbkeyform = strtr( $title, ' ', '_' );
 592                 $t->mArticleID = ( $ns >= 0 ) ? -1 : 0;
 593                 $t->mUrlform = wfUrlencode( $t->mDbkeyform );
 594                 $t->mTextform = strtr( $title, '_', ' ' );
 595                 return $t;
 596         }
 597
 598         /**
 599          * Create a new Title from a namespace index and a DB key.
 600          * The parameters will be checked for validity, which is a bit slower
 601          * than makeTitle() but safer for user-provided data.
 602          *
 603          * Title objects returned by makeTitleSafe() are guaranteed to be valid,
 604          * that is, they return true from the isValid() method. If no valid Title
 605          * can be constructed from the input, this method returns null.
 606          *
 607          * @param int $ns The namespace of the article
 608          * @param string $title Database key form
 609          * @param string $fragment The link fragment (after the "#")
 610          * @param string $interwiki Interwiki prefix
 611          * @return Title|null The new object, or null on an error
 612          */
 613         public static function makeTitleSafe( $ns, $title, $fragment = '', $interwiki = '' ) {
 614                 // NOTE: ideally, this would just call makeTitle() and then isValid(),
 615                 // but presently, that means more overhead on a potential performance hotspot.
 616
 617                 if ( !MediaWikiServices::getInstance()->getNamespaceInfo()->exists( $ns ) ) {
 618                         return null;
 619                 }
 620
 621                 $t = new Title();
 622                 $t->mDbkeyform = self::makeName( $ns, $title, $fragment, $interwiki, true );
 623
 624                 try {
 625                         $t->secureAndSplit();
 626                         return $t;
 627                 } catch ( MalformedTitleException $ex ) {
 628                         return null;
 629                 }
 630         }
 631
 632         /**
 633          * Create a new Title for the Main Page
 634          *
 635          * This uses the 'mainpage' interface message, which could be specified in
 636          * `$wgForceUIMsgAsContentMsg`. If that is the case, then calling this method
 637          * will use the user language, which would involve initialising the session
 638          * via `RequestContext::getMain()->getLanguage()`. For session-less endpoints,
 639          * be sure to pass in a MessageLocalizer (such as your own RequestContext,
 640          * or ResourceloaderContext) to prevent an error.
 641          *
 642          * @note The Title instance returned by this method is not guaranteed to be a fresh instance.
 643          * It may instead be a cached instance created previously, with references to it remaining
 644          * elsewhere.
 645          *
 646          * @param MessageLocalizer|null $localizer An optional context to use (since 1.34)
 647          * @return Title
 648          */
 649         public static function newMainPage( MessageLocalizer $localizer = null ) {
 650                 if ( $localizer ) {
 651                         $msg = $localizer->msg( 'mainpage' );
 652                 } else {
 653                         $msg = wfMessage( 'mainpage' );
 654                 }
 655
 656                 $title = self::newFromText( $msg->inContentLanguage()->text() );
 657
 658                 // Every page renders at least one link to the Main Page (e.g. sidebar).
 659                 // If the localised value is invalid, don't produce fatal errors that
 660                 // would make the wiki inaccessible (and hard to fix the invalid message).
 661                 // Gracefully fallback...
 662                 if ( !$title ) {
 663                         $title = self::newFromText( 'Main Page' );
 664                 }
 665                 return $title;
 666         }
 667
 668         /**
 669          * Get the prefixed DB key associated with an ID
 670          *
 671          * @param int $id The page_id of the article
 672          * @return string|null An object representing the article, or null if no such article was found
 673          */
 674         public static function nameOf( $id ) {
 675                 $dbr = wfGetDB( DB_REPLICA );
 676
 677                 $s = $dbr->selectRow(
 678                         'page',
 679                         [ 'page_namespace', 'page_title' ],
 680                         [ 'page_id' => $id ],
 681                         __METHOD__
 682                 );
 683                 if ( $s === false ) {
 684                         return null;
 685                 }
 686
 687                 return self::makeName( $s->page_namespace, $s->page_title );
 688         }
 689
 690         /**
 691          * Get a regex character class describing the legal characters in a link
 692          *
 693          * @return string The list of characters, not delimited
 694          */
 695         public static function legalChars() {
 696                 global $wgLegalTitleChars;
 697                 return $wgLegalTitleChars;
 698         }
 699
 700         /**
 701          * Utility method for converting a character sequence from bytes to Unicode.
 702          *
 703          * Primary usecase being converting $wgLegalTitleChars to a sequence usable in
 704          * javascript, as PHP uses UTF-8 bytes where javascript uses Unicode code units.
 705          *
 706          * @param string $byteClass
 707          * @return string
 708          */
 709         public static function convertByteClassToUnicodeClass( $byteClass ) {
 710                 $length = strlen( $byteClass );
 711                 // Input token queue
 712                 $x0 = $x1 = $x2 = '';
 713                 // Decoded queue
 714                 $d0 = $d1 = $d2 = '';
 715                 // Decoded integer codepoints
 716                 $ord0 = $ord1 = $ord2 = 0;
 717                 // Re-encoded queue
 718                 $r0 = $r1 = $r2 = '';
 719                 // Output
 720                 $out = '';
 721                 // Flags
 722                 $allowUnicode = false;
 723                 for ( $pos = 0; $pos < $length; $pos++ ) {
 724                         // Shift the queues down
 725                         $x2 = $x1;
 726                         $x1 = $x0;
 727                         $d2 = $d1;
 728                         $d1 = $d0;
 729                         $ord2 = $ord1;
 730                         $ord1 = $ord0;
 731                         $r2 = $r1;
 732                         $r1 = $r0;
 733                         // Load the current input token and decoded values
 734                         $inChar = $byteClass[$pos];
 735                         if ( $inChar == '\\' ) {
 736                                 if ( preg_match( '/x([0-9a-fA-F]{2})/A', $byteClass, $m, 0, $pos + 1 ) ) {
 737                                         $x0 = $inChar . $m[0];
 738                                         $d0 = chr( hexdec( $m[1] ) );
 739                                         $pos += strlen( $m[0] );
 740                                 } elseif ( preg_match( '/[0-7]{3}/A', $byteClass, $m, 0, $pos + 1 ) ) {
 741                                         $x0 = $inChar . $m[0];
 742                                         $d0 = chr( octdec( $m[0] ) );
 743                                         $pos += strlen( $m[0] );
 744                                 } elseif ( $pos + 1 >= $length ) {
 745                                         $x0 = $d0 = '\\';
 746                                 } else {
 747                                         $d0 = $byteClass[$pos + 1];
 748                                         $x0 = $inChar . $d0;
 749                                         $pos += 1;
 750                                 }
 751                         } else {
 752                                 $x0 = $d0 = $inChar;
 753                         }
 754                         $ord0 = ord( $d0 );
 755                         // Load the current re-encoded value
 756                         if ( $ord0 < 32 || $ord0 == 0x7f ) {
 757                                 $r0 = sprintf( '\x%02x', $ord0 );
 758                         } elseif ( $ord0 >= 0x80 ) {
 759                                 // Allow unicode if a single high-bit character appears
 760                                 $r0 = sprintf( '\x%02x', $ord0 );
 761                                 $allowUnicode = true;
 762                                 // @phan-suppress-next-line PhanParamSuspiciousOrder false positive
 763                         } elseif ( strpos( '-\\[]^', $d0 ) !== false ) {
 764                                 $r0 = '\\' . $d0;
 765                         } else {
 766                                 $r0 = $d0;
 767                         }
 768                         // Do the output
 769                         if ( $x0 !== '' && $x1 === '-' && $x2 !== '' ) {
 770                                 // Range
 771                                 if ( $ord2 > $ord0 ) {
 772                                         // Empty range
 773                                 } elseif ( $ord0 >= 0x80 ) {
 774                                         // Unicode range
 775                                         $allowUnicode = true;
 776                                         if ( $ord2 < 0x80 ) {
 777                                                 // Keep the non-unicode section of the range
 778                                                 $out .= "$r2-\\x7F";
 779                                         }
 780                                 } else {
 781                                         // Normal range
 782                                         $out .= "$r2-$r0";
 783                                 }
 784                                 // Reset state to the initial value
 785                                 $x0 = $x1 = $d0 = $d1 = $r0 = $r1 = '';
 786                         } elseif ( $ord2 < 0x80 ) {
 787                                 // ASCII character
 788                                 $out .= $r2;
 789                         }
 790                 }
 791                 if ( $ord1 < 0x80 ) {
 792                         $out .= $r1;
 793                 }
 794                 if ( $ord0 < 0x80 ) {
 795                         $out .= $r0;
 796                 }
 797                 if ( $allowUnicode ) {
 798                         $out .= '\u0080-\uFFFF';
 799                 }
 800                 return $out;
 801         }
 802
 803         /**
 804          * Make a prefixed DB key from a DB key and a namespace index
 805          *
 806          * @param int $ns Numerical representation of the namespace
 807          * @param string $title The DB key form the title
 808          * @param string $fragment The link fragment (after the "#")
 809          * @param string $interwiki The interwiki prefix
 810          * @param bool $canonicalNamespace If true, use the canonical name for
 811          *   $ns instead of the localized version.
 812          * @return string The prefixed form of the title
 813          */
 814         public static function makeName( $ns, $title, $fragment = '', $interwiki = '',
 815                 $canonicalNamespace = false
 816         ) {
 817                 if ( $canonicalNamespace ) {
 818                         $namespace = MediaWikiServices::getInstance()->getNamespaceInfo()->
 819                                 getCanonicalName( $ns );
 820                 } else {
 821                         $namespace = MediaWikiServices::getInstance()->getContentLanguage()->getNsText( $ns );
 822                 }
 823                 $name = $namespace == '' ? $title : "$namespace:$title";
 824                 if ( strval( $interwiki ) != '' ) {
 825                         $name = "$interwiki:$name";
 826                 }
 827                 if ( strval( $fragment ) != '' ) {
 828                         $name .= '#' . $fragment;
 829                 }
 830                 return $name;
 831         }
 832
 833         /**
 834          * Callback for usort() to do title sorts by (namespace, title)
 835          *
 836          * @param LinkTarget $a
 837          * @param LinkTarget $b
 838          *
 839          * @return int Result of string comparison, or namespace comparison
 840          */
 841         public static function compare( LinkTarget $a, LinkTarget $b ) {
 842                 return $a->getNamespace() <=> $b->getNamespace()
 843                         ?: strcmp( $a->getText(), $b->getText() );
 844         }
 845
 846         /**
 847          * Returns true if the title is valid, false if it is invalid.
 848          *
 849          * Valid titles can be round-tripped via makeTitle() and newFromText().
 850          * Their DB key can be used in the database, though it may not have the correct
 851          * capitalization.
 852          *
 853          * Invalid titles may get returned from makeTitle(), and it may be useful to
 854          * allow them to exist, e.g. in order to process log entries about pages in
 855          * namespaces that belong to extensions that are no longer installed.
 856          *
 857          * @note This method is relatively expensive. When constructing Title
 858          * objects that need to be valid, use an instantiator method that is guaranteed
 859          * to return valid titles, such as makeTitleSafe() or newFromText().
 860          *
 861          * @return bool
 862          */
 863         public function isValid() {
 864                 $services = MediaWikiServices::getInstance();
 865                 if ( !$services->getNamespaceInfo()->exists( $this->mNamespace ) ) {
 866                         return false;
 867                 }
 868
 869                 try {
 870                         $services->getTitleParser()->parseTitle( $this->mDbkeyform, $this->mNamespace );
 871                 } catch ( MalformedTitleException $ex ) {
 872                         return false;
 873                 }
 874
 875                 try {
 876                         // Title value applies basic syntax checks. Should perhaps be moved elsewhere.
 877                         new TitleValue(
 878                                 $this->mNamespace,
 879                                 $this->mDbkeyform,
 880                                 $this->mFragment,
 881                                 $this->mInterwiki
 882                         );
 883                 } catch ( InvalidArgumentException $ex ) {
 884                         return false;
 885                 }
 886
 887                 return true;
 888         }
 889
 890         /**
 891          * Determine whether the object refers to a page within
 892          * this project (either this wiki or a wiki with a local
 893          * interwiki, see https://www.mediawiki.org/wiki/Manual:Interwiki_table#iw_local )
 894          *
 895          * @return bool True if this is an in-project interwiki link or a wikilink, false otherwise
 896          */
 897         public function isLocal() {
 898                 if ( $this->isExternal() ) {
 899                         $iw = self::getInterwikiLookup()->fetch( $this->mInterwiki );
 900                         if ( $iw ) {
 901                                 return $iw->isLocal();
 902                         }
 903                 }
 904                 return true;
 905         }
 906
 907         /**
 908          * Is this Title interwiki?
 909          *
 910          * @return bool
 911          */
 912         public function isExternal() {
 913                 return $this->mInterwiki !== '';
 914         }
 915
 916         /**
 917          * Get the interwiki prefix
 918          *
 919          * Use Title::isExternal to check if a interwiki is set
 920          *
 921          * @return string Interwiki prefix
 922          */
 923         public function getInterwiki() {
 924                 return $this->mInterwiki;
 925         }
 926
 927         /**
 928          * Was this a local interwiki link?
 929          *
 930          * @return bool
 931          */
 932         public function wasLocalInterwiki() {
 933                 return $this->mLocalInterwiki;
 934         }
 935
 936         /**
 937          * Determine whether the object refers to a page within
 938          * this project and is transcludable.
 939          *
 940          * @return bool True if this is transcludable
 941          */
 942         public function isTrans() {
 943                 if ( !$this->isExternal() ) {
 944                         return false;
 945                 }
 946
 947                 return self::getInterwikiLookup()->fetch( $this->mInterwiki )->isTranscludable();
 948         }
 949
 950         /**
 951          * Returns the DB name of the distant wiki which owns the object.
 952          *
 953          * @return string|false The DB name
 954          */
 955         public function getTransWikiID() {
 956                 if ( !$this->isExternal() ) {
 957                         return false;
 958                 }
 959
 960                 return self::getInterwikiLookup()->fetch( $this->mInterwiki )->getWikiID();
 961         }
 962
 963         /**
 964          * Get a TitleValue object representing this Title.
 965          *
 966          * @note Not all valid Titles have a corresponding valid TitleValue
 967          * (e.g. TitleValues cannot represent page-local links that have a
 968          * fragment but no title text).
 969          *
 970          * @return TitleValue|null
 971          */
 972         public function getTitleValue() {
 973                 if ( $this->mTitleValue === null ) {
 974                         try {
 975                                 $this->mTitleValue = new TitleValue(
 976                                         $this->mNamespace,
 977                                         $this->mDbkeyform,
 978                                         $this->mFragment,
 979                                         $this->mInterwiki
 980                                 );
 981                         } catch ( InvalidArgumentException $ex ) {
 982                                 wfDebug( __METHOD__ . ': Can\'t create a TitleValue for [[' .
 983                                         $this->getPrefixedText() . ']]: ' . $ex->getMessage() . "\n" );
 984                         }
 985                 }
 986
 987                 return $this->mTitleValue;
 988         }
 989
 990         /**
 991          * Get the text form (spaces not underscores) of the main part
 992          *
 993          * @return string Main part of the title
 994          */
 995         public function getText() {
 996                 return $this->mTextform;
 997         }
 998
 999         /**
1000          * Get the URL-encoded form of the main part
1001          *
1002          * @return string Main part of the title, URL-encoded
1003          */
1004         public function getPartialURL() {
1005                 return $this->mUrlform;
1006         }
1007
1008         /**
1009          * Get the main part with underscores
1010          *
1011          * @return string Main part of the title, with underscores
1012          */
1013         public function getDBkey() {
1014                 return $this->mDbkeyform;
1015         }
1016
1017         /**
1018          * Get the DB key with the initial letter case as specified by the user
1019          * @deprecated since 1.33; please use Title::getDBKey() instead
1020          *
1021          * @return string DB key
1022          */
1023         function getUserCaseDBKey() {
1024                 if ( !is_null( $this->mUserCaseDBKey ) ) {
1025                         return $this->mUserCaseDBKey;
1026                 } else {
1027                         // If created via makeTitle(), $this->mUserCaseDBKey is not set.
1028                         return $this->mDbkeyform;
1029                 }
1030         }
1031
1032         /**
1033          * Get the namespace index, i.e. one of the NS_xxxx constants.
1034          *
1035          * @return int Namespace index
1036          */
1037         public function getNamespace() {
1038                 return $this->mNamespace;
1039         }
1040
1041         /**
1042          * Get the page's content model id, see the CONTENT_MODEL_XXX constants.
1043          *
1044          * @todo Deprecate this in favor of SlotRecord::getModel()
1045          *
1046          * @param int $flags Either a bitfield of class READ_* constants or GAID_FOR_UPDATE
1047          * @return string Content model id
1048          */
1049         public function getContentModel( $flags = 0 ) {
1050                 if ( $this->mForcedContentModel ) {
1051                         if ( !$this->mContentModel ) {
1052                                 throw new RuntimeException( 'Got out of sync; an empty model is being forced' );
1053                         }
1054                         // Content model is locked to the currently loaded one
1055                         return $this->mContentModel;
1056                 }
1057
1058                 if ( DBAccessObjectUtils::hasFlags( $flags, self::READ_LATEST ) ) {
1059                         $this->lazyFillContentModel( $this->loadFieldFromDB( 'page_content_model', $flags ) );
1060                 } elseif (
1061                         ( !$this->mContentModel || $flags & self::GAID_FOR_UPDATE ) &&
1062                         $this->getArticleId( $flags )
1063                 ) {
1064                         $linkCache = MediaWikiServices::getInstance()->getLinkCache();
1065                         $linkCache->addLinkObj( $this ); # in case we already had an article ID
1066                         $this->lazyFillContentModel( $linkCache->getGoodLinkFieldObj( $this, 'model' ) );
1067                 }
1068
1069                 if ( !$this->mContentModel ) {
1070                         $this->lazyFillContentModel( ContentHandler::getDefaultModelFor( $this ) );
1071                 }
1072
1073                 return $this->mContentModel;
1074         }
1075
1076         /**
1077          * Convenience method for checking a title's content model name
1078          *
1079          * @param string $id The content model ID (use the CONTENT_MODEL_XXX constants).
1080          * @return bool True if $this->getContentModel() == $id
1081          */
1082         public function hasContentModel( $id ) {
1083                 return $this->getContentModel() == $id;
1084         }
1085
1086         /**
1087          * Set a proposed content model for the page for permissions checking
1088          *
1089          * This does not actually change the content model of a title in the DB.
1090          * It only affects this particular Title instance. The content model is
1091          * forced to remain this value until another setContentModel() call.
1092          *
1093          * ContentHandler::canBeUsedOn() should be checked before calling this
1094          * if there is any doubt regarding the applicability of the content model
1095          *
1096          * @since 1.28
1097          * @param string $model CONTENT_MODEL_XXX constant
1098          */
1099         public function setContentModel( $model ) {
1100                 if ( (string)$model === '' ) {
1101                         throw new InvalidArgumentException( "Missing CONTENT_MODEL_* constant" );
1102                 }
1103
1104                 $this->mContentModel = $model;
1105                 $this->mForcedContentModel = true;
1106         }
1107
1108         /**
1109          * If the content model field is not frozen then update it with a retreived value
1110          *
1111          * @param string|bool $model CONTENT_MODEL_XXX constant or false
1112          */
1113         private function lazyFillContentModel( $model ) {
1114                 if ( !$this->mForcedContentModel ) {
1115                         $this->mContentModel = ( $model === false ) ? false : (string)$model;
1116                 }
1117         }
1118
1119         /**
1120          * Get the namespace text
1121          *
1122          * @return string|false Namespace text
1123          */
1124         public function getNsText() {
1125                 if ( $this->isExternal() ) {
1126                         // This probably shouldn't even happen, except for interwiki transclusion.
1127                         // If possible, use the canonical name for the foreign namespace.
1128                         $nsText = MediaWikiServices::getInstance()->getNamespaceInfo()->
1129                                 getCanonicalName( $this->mNamespace );
1130                         if ( $nsText !== false ) {
1131                                 return $nsText;
1132                         }
1133                 }
1134
1135                 try {
1136                         $formatter = self::getTitleFormatter();
1137                         return $formatter->getNamespaceName( $this->mNamespace, $this->mDbkeyform );
1138                 } catch ( InvalidArgumentException $ex ) {
1139                         wfDebug( __METHOD__ . ': ' . $ex->getMessage() . "\n" );
1140                         return false;
1141                 }
1142         }
1143
1144         /**
1145          * Get the namespace text of the subject (rather than talk) page
1146          *
1147          * @return string Namespace text
1148          */
1149         public function getSubjectNsText() {
1150                 $services = MediaWikiServices::getInstance();
1151                 return $services->getContentLanguage()->
1152                         getNsText( $services->getNamespaceInfo()->getSubject( $this->mNamespace ) );
1153         }
1154
1155         /**
1156          * Get the namespace text of the talk page
1157          *
1158          * @return string Namespace text
1159          */
1160         public function getTalkNsText() {
1161                 $services = MediaWikiServices::getInstance();
1162                 return $services->getContentLanguage()->
1163                         getNsText( $services->getNamespaceInfo()->getTalk( $this->mNamespace ) );
1164         }
1165
1166         /**
1167          * Can this title have a corresponding talk page?
1168          *
1169          * False for relative section links (with getText() === ''),
1170          * interwiki links (with getInterwiki() !== ''), and pages in NS_SPECIAL.
1171          *
1172          * @see NamespaceInfo::canHaveTalkPage
1173          * @since 1.30
1174          *
1175          * @return bool True if this title either is a talk page or can have a talk page associated.
1176          */
1177         public function canHaveTalkPage() {
1178                 return MediaWikiServices::getInstance()->getNamespaceInfo()->canHaveTalkPage( $this );
1179         }
1180
1181         /**
1182          * Is this in a namespace that allows actual pages?
1183          *
1184          * @return bool
1185          */
1186         public function canExist() {
1187                 return $this->mNamespace >= NS_MAIN;
1188         }
1189
1190         /**
1191          * Can this title be added to a user's watchlist?
1192          *
1193          * False for relative section links (with getText() === ''),
1194          * interwiki links (with getInterwiki() !== ''), and pages in NS_SPECIAL.
1195          *
1196          * @return bool
1197          */
1198         public function isWatchable() {
1199                 $nsInfo = MediaWikiServices::getInstance()->getNamespaceInfo();
1200                 return $this->getText() !== '' && !$this->isExternal() &&
1201                         $nsInfo->isWatchable( $this->mNamespace );
1202         }
1203
1204         /**
1205          * Returns true if this is a special page.
1206          *
1207          * @return bool
1208          */
1209         public function isSpecialPage() {
1210                 return $this->mNamespace == NS_SPECIAL;
1211         }
1212
1213         /**
1214          * Returns true if this title resolves to the named special page
1215          *
1216          * @param string $name The special page name
1217          * @return bool
1218          */
1219         public function isSpecial( $name ) {
1220                 if ( $this->isSpecialPage() ) {
1221                         list( $thisName, /* $subpage */ ) =
1222                                 MediaWikiServices::getInstance()->getSpecialPageFactory()->
1223                                         resolveAlias( $this->mDbkeyform );
1224                         if ( $name == $thisName ) {
1225                                 return true;
1226                         }
1227                 }
1228                 return false;
1229         }
1230
1231         /**
1232          * If the Title refers to a special page alias which is not the local default, resolve
1233          * the alias, and localise the name as necessary.  Otherwise, return $this
1234          *
1235          * @return Title
1236          */
1237         public function fixSpecialName() {
1238                 if ( $this->isSpecialPage() ) {
1239                         $spFactory = MediaWikiServices::getInstance()->getSpecialPageFactory();
1240                         list( $canonicalName, $par ) = $spFactory->resolveAlias( $this->mDbkeyform );
1241                         if ( $canonicalName ) {
1242                                 $localName = $spFactory->getLocalNameFor( $canonicalName, $par );
1243                                 if ( $localName != $this->mDbkeyform ) {
1244                                         return self::makeTitle( NS_SPECIAL, $localName );
1245                                 }
1246                         }
1247                 }
1248                 return $this;
1249         }
1250
1251         /**
1252          * Returns true if the title is inside the specified namespace.
1253          *
1254          * Please make use of this instead of comparing to getNamespace()
1255          * This function is much more resistant to changes we may make
1256          * to namespaces than code that makes direct comparisons.
1257          * @param int $ns The namespace
1258          * @return bool
1259          * @since 1.19
1260          */
1261         public function inNamespace( $ns ) {
1262                 return MediaWikiServices::getInstance()->getNamespaceInfo()->
1263                         equals( $this->mNamespace, $ns );
1264         }
1265
1266         /**
1267          * Returns true if the title is inside one of the specified namespaces.
1268          *
1269          * @param int|int[] $namespaces,... The namespaces to check for
1270          * @return bool
1271          * @since 1.19
1272          * @suppress PhanCommentParamOnEmptyParamList Cannot make variadic due to HHVM bug, T191668#5263929
1273          */
1274         public function inNamespaces( /* ... */ ) {
1275                 $namespaces = func_get_args();
1276                 if ( count( $namespaces ) > 0 && is_array( $namespaces[0] ) ) {
1277                         $namespaces = $namespaces[0];
1278                 }
1279
1280                 foreach ( $namespaces as $ns ) {
1281                         if ( $this->inNamespace( $ns ) ) {
1282                                 return true;
1283                         }
1284                 }
1285
1286                 return false;
1287         }
1288
1289         /**
1290          * Returns true if the title has the same subject namespace as the
1291          * namespace specified.
1292          * For example this method will take NS_USER and return true if namespace
1293          * is either NS_USER or NS_USER_TALK since both of them have NS_USER
1294          * as their subject namespace.
1295          *
1296          * This is MUCH simpler than individually testing for equivalence
1297          * against both NS_USER and NS_USER_TALK, and is also forward compatible.
1298          * @since 1.19
1299          * @param int $ns
1300          * @return bool
1301          */
1302         public function hasSubjectNamespace( $ns ) {
1303                 return MediaWikiServices::getInstance()->getNamespaceInfo()->
1304                         subjectEquals( $this->mNamespace, $ns );
1305         }
1306
1307         /**
1308          * Is this Title in a namespace which contains content?
1309          * In other words, is this a content page, for the purposes of calculating
1310          * statistics, etc?
1311          *
1312          * @return bool
1313          */
1314         public function isContentPage() {
1315                 return MediaWikiServices::getInstance()->getNamespaceInfo()->
1316                         isContent( $this->mNamespace );
1317         }
1318
1319         /**
1320          * Would anybody with sufficient privileges be able to move this page?
1321          * Some pages just aren't movable.
1322          *
1323          * @return bool
1324          */
1325         public function isMovable() {
1326                 if (
1327                         !MediaWikiServices::getInstance()->getNamespaceInfo()->
1328                                 isMovable( $this->mNamespace ) || $this->isExternal()
1329                 ) {
1330                         // Interwiki title or immovable namespace. Hooks don't get to override here
1331                         return false;
1332                 }
1333
1334                 $result = true;
1335                 Hooks::run( 'TitleIsMovable', [ $this, &$result ] );
1336                 return $result;
1337         }
1338
1339         /**
1340          * Is this the mainpage?
1341          * @note Title::newFromText seems to be sufficiently optimized by the title
1342          * cache that we don't need to over-optimize by doing direct comparisons and
1343          * accidentally creating new bugs where $title->equals( Title::newFromText() )
1344          * ends up reporting something differently than $title->isMainPage();
1345          *
1346          * @since 1.18
1347          * @return bool
1348          */
1349         public function isMainPage() {
1350                 return $this->equals( self::newMainPage() );
1351         }
1352
1353         /**
1354          * Is this a subpage?
1355          *
1356          * @return bool
1357          */
1358         public function isSubpage() {
1359                 return MediaWikiServices::getInstance()->getNamespaceInfo()->
1360                         hasSubpages( $this->mNamespace )
1361                         ? strpos( $this->getText(), '/' ) !== false
1362                         : false;
1363         }
1364
1365         /**
1366          * Is this a conversion table for the LanguageConverter?
1367          *
1368          * @return bool
1369          */
1370         public function isConversionTable() {
1371                 // @todo ConversionTable should become a separate content model.
1372
1373                 return $this->mNamespace == NS_MEDIAWIKI &&
1374                         strpos( $this->getText(), 'Conversiontable/' ) === 0;
1375         }
1376
1377         /**
1378          * Does that page contain wikitext, or it is JS, CSS or whatever?
1379          *
1380          * @return bool
1381          */
1382         public function isWikitextPage() {
1383                 return $this->hasContentModel( CONTENT_MODEL_WIKITEXT );
1384         }
1385
1386         /**
1387          * Could this MediaWiki namespace page contain custom CSS, JSON, or JavaScript for the
1388          * global UI. This is generally true for pages in the MediaWiki namespace having
1389          * CONTENT_MODEL_CSS, CONTENT_MODEL_JSON, or CONTENT_MODEL_JAVASCRIPT.
1390          *
1391          * This method does *not* return true for per-user JS/JSON/CSS. Use isUserConfigPage()
1392          * for that!
1393          *
1394          * Note that this method should not return true for pages that contain and show
1395          * "inactive" CSS, JSON, or JS.
1396          *
1397          * @return bool
1398          * @since 1.31
1399          */
1400         public function isSiteConfigPage() {
1401                 return (
1402                         $this->isSiteCssConfigPage()
1403                         || $this->isSiteJsonConfigPage()
1404                         || $this->isSiteJsConfigPage()
1405                 );
1406         }
1407
1408         /**
1409          * Is this a "config" (.css, .json, or .js) sub-page of a user page?
1410          *
1411          * @return bool
1412          * @since 1.31
1413          */
1414         public function isUserConfigPage() {
1415                 return (
1416                         $this->isUserCssConfigPage()
1417                         || $this->isUserJsonConfigPage()
1418                         || $this->isUserJsConfigPage()
1419                 );
1420         }
1421
1422         /**
1423          * Trim down a .css, .json, or .js subpage title to get the corresponding skin name
1424          *
1425          * @return string Containing skin name from .css, .json, or .js subpage title
1426          * @since 1.31
1427          */
1428         public function getSkinFromConfigSubpage() {
1429                 $subpage = explode( '/', $this->mTextform );
1430                 $subpage = $subpage[count( $subpage ) - 1];
1431                 $lastdot = strrpos( $subpage, '.' );
1432                 if ( $lastdot === false ) {
1433                         return $subpage; # Never happens: only called for names ending in '.css'/'.json'/'.js'
1434                 }
1435                 return substr( $subpage, 0, $lastdot );
1436         }
1437
1438         /**
1439          * Is this a CSS "config" sub-page of a user page?
1440          *
1441          * @return bool
1442          * @since 1.31
1443          */
1444         public function isUserCssConfigPage() {
1445                 return (
1446                         NS_USER == $this->mNamespace
1447                         && $this->isSubpage()
1448                         && $this->hasContentModel( CONTENT_MODEL_CSS )
1449                 );
1450         }
1451
1452         /**
1453          * Is this a JSON "config" sub-page of a user page?
1454          *
1455          * @return bool
1456          * @since 1.31
1457          */
1458         public function isUserJsonConfigPage() {
1459                 return (
1460                         NS_USER == $this->mNamespace
1461                         && $this->isSubpage()
1462                         && $this->hasContentModel( CONTENT_MODEL_JSON )
1463                 );
1464         }
1465
1466         /**
1467          * Is this a JS "config" sub-page of a user page?
1468          *
1469          * @return bool
1470          * @since 1.31
1471          */
1472         public function isUserJsConfigPage() {
1473                 return (
1474                         NS_USER == $this->mNamespace
1475                         && $this->isSubpage()
1476                         && $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT )
1477                 );
1478         }
1479
1480         /**
1481          * Is this a sitewide CSS "config" page?
1482          *
1483          * @return bool
1484          * @since 1.32
1485          */
1486         public function isSiteCssConfigPage() {
1487                 return (
1488                         NS_MEDIAWIKI == $this->mNamespace
1489                         && (
1490                                 $this->hasContentModel( CONTENT_MODEL_CSS )
1491                                 // paranoia - a MediaWiki: namespace page with mismatching extension and content
1492                                 // model is probably by mistake and might get handled incorrectly (see e.g. T112937)
1493                                 || substr( $this->mDbkeyform, -4 ) === '.css'
1494                         )
1495                 );
1496         }
1497
1498         /**
1499          * Is this a sitewide JSON "config" page?
1500          *
1501          * @return bool
1502          * @since 1.32
1503          */
1504         public function isSiteJsonConfigPage() {
1505                 return (
1506                         NS_MEDIAWIKI == $this->mNamespace
1507                         && (
1508                                 $this->hasContentModel( CONTENT_MODEL_JSON )
1509                                 // paranoia - a MediaWiki: namespace page with mismatching extension and content
1510                                 // model is probably by mistake and might get handled incorrectly (see e.g. T112937)
1511                                 || substr( $this->mDbkeyform, -5 ) === '.json'
1512                         )
1513                 );
1514         }
1515
1516         /**
1517          * Is this a sitewide JS "config" page?
1518          *
1519          * @return bool
1520          * @since 1.31
1521          */
1522         public function isSiteJsConfigPage() {
1523                 return (
1524                         NS_MEDIAWIKI == $this->mNamespace
1525                         && (
1526                                 $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT )
1527                                 // paranoia - a MediaWiki: namespace page with mismatching extension and content
1528                                 // model is probably by mistake and might get handled incorrectly (see e.g. T112937)
1529                                 || substr( $this->mDbkeyform, -3 ) === '.js'
1530                         )
1531                 );
1532         }
1533
1534         /**
1535          * Is this a message which can contain raw HTML?
1536          *
1537          * @return bool
1538          * @since 1.32
1539          */
1540         public function isRawHtmlMessage() {
1541                 global $wgRawHtmlMessages;
1542
1543                 if ( !$this->inNamespace( NS_MEDIAWIKI ) ) {
1544                         return false;
1545                 }
1546                 $message = lcfirst( $this->getRootTitle()->getDBkey() );
1547                 return in_array( $message, $wgRawHtmlMessages, true );
1548         }
1549
1550         /**
1551          * Is this a talk page of some sort?
1552          *
1553          * @return bool
1554          */
1555         public function isTalkPage() {
1556                 return MediaWikiServices::getInstance()->getNamespaceInfo()->
1557                         isTalk( $this->mNamespace );
1558         }
1559
1560         /**
1561          * Get a Title object associated with the talk page of this article
1562          *
1563          * @deprecated since 1.34, use getTalkPageIfDefined() or NamespaceInfo::getTalkPage()
1564          *             with NamespaceInfo::canHaveTalkPage().
1565          * @return Title The object for the talk page
1566          * @throws MWException if $target doesn't have talk pages, e.g. because it's in NS_SPECIAL
1567          *         or because it's a relative link, or an interwiki link.
1568          */
1569         public function getTalkPage() {
1570                 return self::castFromLinkTarget(
1571                         MediaWikiServices::getInstance()->getNamespaceInfo()->getTalkPage( $this ) );
1572         }
1573
1574         /**
1575          * Get a Title object associated with the talk page of this article,
1576          * if such a talk page can exist.
1577          *
1578          * @since 1.30
1579          *
1580          * @return Title|null The object for the talk page,
1581          *         or null if no associated talk page can exist, according to canHaveTalkPage().
1582          */
1583         public function getTalkPageIfDefined() {
1584                 if ( !$this->canHaveTalkPage() ) {
1585                         return null;
1586                 }
1587
1588                 return $this->getTalkPage();
1589         }
1590
1591         /**
1592          * Get a title object associated with the subject page of this
1593          * talk page
1594          *
1595          * @deprecated since 1.34, use NamespaceInfo::getSubjectPage
1596          * @return Title The object for the subject page
1597          */
1598         public function getSubjectPage() {
1599                 return self::castFromLinkTarget(
1600                         MediaWikiServices::getInstance()->getNamespaceInfo()->getSubjectPage( $this ) );
1601         }
1602
1603         /**
1604          * Get the other title for this page, if this is a subject page
1605          * get the talk page, if it is a subject page get the talk page
1606          *
1607          * @deprecated since 1.34, use NamespaceInfo::getAssociatedPage
1608          * @since 1.25
1609          * @throws MWException If the page doesn't have an other page
1610          * @return Title
1611          */
1612         public function getOtherPage() {
1613                 return self::castFromLinkTarget(
1614                         MediaWikiServices::getInstance()->getNamespaceInfo()->getAssociatedPage( $this ) );
1615         }
1616
1617         /**
1618          * Get the default namespace index, for when there is no namespace
1619          *
1620          * @return int Default namespace index
1621          */
1622         public function getDefaultNamespace() {
1623                 return $this->mDefaultNamespace;
1624         }
1625
1626         /**
1627          * Get the Title fragment (i.e.\ the bit after the #) in text form
1628          *
1629          * Use Title::hasFragment to check for a fragment
1630          *
1631          * @return string Title fragment
1632          */
1633         public function getFragment() {
1634                 return $this->mFragment;
1635         }
1636
1637         /**
1638          * Check if a Title fragment is set
1639          *
1640          * @return bool
1641          * @since 1.23
1642          */
1643         public function hasFragment() {
1644                 return $this->mFragment !== '';
1645         }
1646
1647         /**
1648          * Get the fragment in URL form, including the "#" character if there is one
1649          *
1650          * @return string Fragment in URL form
1651          */
1652         public function getFragmentForURL() {
1653                 if ( !$this->hasFragment() ) {
1654                         return '';
1655                 } elseif ( $this->isExternal() ) {
1656                         // Note: If the interwiki is unknown, it's treated as a namespace on the local wiki,
1657                         // so we treat it like a local interwiki.
1658                         $interwiki = self::getInterwikiLookup()->fetch( $this->mInterwiki );
1659                         if ( $interwiki && !$interwiki->isLocal() ) {
1660                                 return '#' . Sanitizer::escapeIdForExternalInterwiki( $this->mFragment );
1661                         }
1662                 }
1663
1664                 return '#' . Sanitizer::escapeIdForLink( $this->mFragment );
1665         }
1666
1667         /**
1668          * Set the fragment for this title. Removes the first character from the
1669          * specified fragment before setting, so it assumes you're passing it with
1670          * an initial "#".
1671          *
1672          * Deprecated for public use, use Title::makeTitle() with fragment parameter,
1673          * or Title::createFragmentTarget().
1674          * Still in active use privately.
1675          *
1676          * @private
1677          * @param string $fragment Text
1678          */
1679         public function setFragment( $fragment ) {
1680                 $this->mFragment = strtr( substr( $fragment, 1 ), '_', ' ' );
1681         }
1682
1683         /**
1684          * Creates a new Title for a different fragment of the same page.
1685          *
1686          * @since 1.27
1687          * @param string $fragment
1688          * @return Title
1689          */
1690         public function createFragmentTarget( $fragment ) {
1691                 return self::makeTitle(
1692                         $this->mNamespace,
1693                         $this->getText(),
1694                         $fragment,
1695                         $this->mInterwiki
1696                 );
1697         }
1698
1699         /**
1700          * Prefix some arbitrary text with the namespace or interwiki prefix
1701          * of this object
1702          *
1703          * @param string $name The text
1704          * @return string The prefixed text
1705          */
1706         private function prefix( $name ) {
1707                 $p = '';
1708                 if ( $this->isExternal() ) {
1709                         $p = $this->mInterwiki . ':';
1710                 }
1711
1712                 if ( $this->mNamespace != 0 ) {
1713                         $nsText = $this->getNsText();
1714
1715                         if ( $nsText === false ) {
1716                                 // See T165149. Awkward, but better than erroneously linking to the main namespace.
1717                                 $nsText = MediaWikiServices::getInstance()->getContentLanguage()->
1718                                         getNsText( NS_SPECIAL ) . ":Badtitle/NS{$this->mNamespace}";
1719                         }
1720
1721                         $p .= $nsText . ':';
1722                 }
1723                 return $p . $name;
1724         }
1725
1726         /**
1727          * Get the prefixed database key form
1728          *
1729          * @return string The prefixed title, with underscores and
1730          *  any interwiki and namespace prefixes
1731          */
1732         public function getPrefixedDBkey() {
1733                 $s = $this->prefix( $this->mDbkeyform );
1734                 $s = strtr( $s, ' ', '_' );
1735                 return $s;
1736         }
1737
1738         /**
1739          * Get the prefixed title with spaces.
1740          * This is the form usually used for display
1741          *
1742          * @return string The prefixed title, with spaces
1743          */
1744         public function getPrefixedText() {
1745                 if ( $this->prefixedText === null ) {
1746                         $s = $this->prefix( $this->mTextform );
1747                         $s = strtr( $s, '_', ' ' );
1748                         $this->prefixedText = $s;
1749                 }
1750                 return $this->prefixedText;
1751         }
1752
1753         /**
1754          * Return a string representation of this title
1755          *
1756          * @return string Representation of this title
1757          */
1758         public function __toString() {
1759                 return $this->getPrefixedText();
1760         }
1761
1762         /**
1763          * Get the prefixed title with spaces, plus any fragment
1764          * (part beginning with '#')
1765          *
1766          * @return string The prefixed title, with spaces and the fragment, including '#'
1767          */
1768         public function getFullText() {
1769                 $text = $this->getPrefixedText();
1770                 if ( $this->hasFragment() ) {
1771                         $text .= '#' . $this->mFragment;
1772                 }
1773                 return $text;
1774         }
1775
1776         /**
1777          * Get the root page name text without a namespace, i.e. the leftmost part before any slashes
1778          *
1779          * @note the return value may contain trailing whitespace and is thus
1780          * not safe for use with makeTitle or TitleValue.
1781          *
1782          * @par Example:
1783          * @code
1784          * Title::newFromText('User:Foo/Bar/Baz')->getRootText();
1785          * # returns: 'Foo'
1786          * @endcode
1787          *
1788          * @return string Root name
1789          * @since 1.20
1790          */
1791         public function getRootText() {
1792                 if (
1793                         !MediaWikiServices::getInstance()->getNamespaceInfo()->
1794                                 hasSubpages( $this->mNamespace )
1795                         || strtok( $this->getText(), '/' ) === false
1796                 ) {
1797                         return $this->getText();
1798                 }
1799
1800                 return strtok( $this->getText(), '/' );
1801         }
1802
1803         /**
1804          * Get the root page name title, i.e. the leftmost part before any slashes
1805          *
1806          * @par Example:
1807          * @code
1808          * Title::newFromText('User:Foo/Bar/Baz')->getRootTitle();
1809          * # returns: Title{User:Foo}
1810          * @endcode
1811          *
1812          * @return Title Root title
1813          * @since 1.20
1814          */
1815         public function getRootTitle() {
1816                 $title = self::makeTitleSafe( $this->mNamespace, $this->getRootText() );
1817                 Assert::postcondition(
1818                         $title !== null,
1819                         'makeTitleSafe() should always return a Title for the text returned by getRootText().'
1820                 );
1821                 return $title;
1822         }
1823
1824         /**
1825          * Get the base page name without a namespace, i.e. the part before the subpage name
1826          *
1827          * @note the return value may contain trailing whitespace and is thus
1828          * not safe for use with makeTitle or TitleValue.
1829          *
1830          * @par Example:
1831          * @code
1832          * Title::newFromText('User:Foo/Bar/Baz')->getBaseText();
1833          * # returns: 'Foo/Bar'
1834          * @endcode
1835          *
1836          * @return string Base name
1837          */
1838         public function getBaseText() {
1839                 $text = $this->getText();
1840                 if (
1841                         !MediaWikiServices::getInstance()->getNamespaceInfo()->
1842                                 hasSubpages( $this->mNamespace )
1843                 ) {
1844                         return $text;
1845                 }
1846
1847                 $lastSlashPos = strrpos( $text, '/' );
1848                 // Don't discard the real title if there's no subpage involved
1849                 if ( $lastSlashPos === false ) {
1850                         return $text;
1851                 }
1852
1853                 return substr( $text, 0, $lastSlashPos );
1854         }
1855
1856         /**
1857          * Get the base page name title, i.e. the part before the subpage name.
1858          *
1859          * @par Example:
1860          * @code
1861          * Title::newFromText('User:Foo/Bar/Baz')->getBaseTitle();
1862          * # returns: Title{User:Foo/Bar}
1863          * @endcode
1864          *
1865          * @return Title Base title
1866          * @since 1.20
1867          */
1868         public function getBaseTitle() {
1869                 $title = self::makeTitleSafe( $this->mNamespace, $this->getBaseText() );
1870                 Assert::postcondition(
1871                         $title !== null,
1872                         'makeTitleSafe() should always return a Title for the text returned by getBaseText().'
1873                 );
1874                 return $title;
1875         }
1876
1877         /**
1878          * Get the lowest-level subpage name, i.e. the rightmost part after any slashes
1879          *
1880          * @par Example:
1881          * @code
1882          * Title::newFromText('User:Foo/Bar/Baz')->getSubpageText();
1883          * # returns: "Baz"
1884          * @endcode
1885          *
1886          * @return string Subpage name
1887          */
1888         public function getSubpageText() {
1889                 if (
1890                         !MediaWikiServices::getInstance()->getNamespaceInfo()->
1891                                 hasSubpages( $this->mNamespace )
1892                 ) {
1893                         return $this->mTextform;
1894                 }
1895                 $parts = explode( '/', $this->mTextform );
1896                 return $parts[count( $parts ) - 1];
1897         }
1898
1899         /**
1900          * Get the title for a subpage of the current page
1901          *
1902          * @par Example:
1903          * @code
1904          * Title::newFromText('User:Foo/Bar/Baz')->getSubpage("Asdf");
1905          * # returns: Title{User:Foo/Bar/Baz/Asdf}
1906          * @endcode
1907          *
1908          * @param string $text The subpage name to add to the title
1909          * @return Title|null Subpage title, or null on an error
1910          * @since 1.20
1911          */
1912         public function getSubpage( $text ) {
1913                 return self::makeTitleSafe(
1914                         $this->mNamespace,
1915                         $this->getText() . '/' . $text,
1916                         '',
1917                         $this->mInterwiki
1918                 );
1919         }
1920
1921         /**
1922          * Get a URL-encoded form of the subpage text
1923          *
1924          * @return string URL-encoded subpage name
1925          */
1926         public function getSubpageUrlForm() {
1927                 $text = $this->getSubpageText();
1928                 $text = wfUrlencode( strtr( $text, ' ', '_' ) );
1929                 return $text;
1930         }
1931
1932         /**
1933          * Get a URL-encoded title (not an actual URL) including interwiki
1934          *
1935          * @return string The URL-encoded form
1936          */
1937         public function getPrefixedURL() {
1938                 $s = $this->prefix( $this->mDbkeyform );
1939                 $s = wfUrlencode( strtr( $s, ' ', '_' ) );
1940                 return $s;
1941         }
1942
1943         /**
1944          * Helper to fix up the get{Canonical,Full,Link,Local,Internal}URL args
1945          * get{Canonical,Full,Link,Local,Internal}URL methods accepted an optional
1946          * second argument named variant. This was deprecated in favor
1947          * of passing an array of option with a "variant" key
1948          * Once $query2 is removed for good, this helper can be dropped
1949          * and the wfArrayToCgi moved to getLocalURL();
1950          *
1951          * @since 1.19 (r105919)
1952          * @param array|string $query
1953          * @param string|string[]|bool $query2
1954          * @return string
1955          */
1956         private static function fixUrlQueryArgs( $query, $query2 = false ) {
1957                 if ( $query2 !== false ) {
1958                         wfDeprecated( "Title::get{Canonical,Full,Link,Local,Internal}URL " .
1959                                 "method called with a second parameter is deprecated. Add your " .
1960                                 "parameter to an array passed as the first parameter.", "1.19" );
1961                 }
1962                 if ( is_array( $query ) ) {
1963                         $query = wfArrayToCgi( $query );
1964                 }
1965                 if ( $query2 ) {
1966                         if ( is_string( $query2 ) ) {
1967                                 // $query2 is a string, we will consider this to be
1968                                 // a deprecated $variant argument and add it to the query
1969                                 $query2 = wfArrayToCgi( [ 'variant' => $query2 ] );
1970                         } else {
1971                                 $query2 = wfArrayToCgi( $query2 );
1972                         }
1973                         // If we have $query content add a & to it first
1974                         if ( $query ) {
1975                                 $query .= '&';
1976                         }
1977                         // Now append the queries together
1978                         $query .= $query2;
1979                 }
1980                 return $query;
1981         }
1982
1983         /**
1984          * Get a real URL referring to this title, with interwiki link and
1985          * fragment
1986          *
1987          * @see self::getLocalURL for the arguments.
1988          * @see wfExpandUrl
1989          * @param string|string[] $query
1990          * @param string|string[]|bool $query2
1991          * @param string|int|null $proto Protocol type to use in URL
1992          * @return string The URL
1993          */
1994         public function getFullURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1995                 $query = self::fixUrlQueryArgs( $query, $query2 );
1996
1997                 # Hand off all the decisions on urls to getLocalURL
1998                 $url = $this->getLocalURL( $query );
1999
2000                 # Expand the url to make it a full url. Note that getLocalURL has the
2001                 # potential to output full urls for a variety of reasons, so we use
2002                 # wfExpandUrl instead of simply prepending $wgServer
2003                 $url = wfExpandUrl( $url, $proto );
2004
2005                 # Finally, add the fragment.
2006                 $url .= $this->getFragmentForURL();
2007                 // Avoid PHP 7.1 warning from passing $this by reference
2008                 $titleRef = $this;
2009                 Hooks::run( 'GetFullURL', [ &$titleRef, &$url, $query ] );
2010                 return $url;
2011         }
2012
2013         /**
2014          * Get a url appropriate for making redirects based on an untrusted url arg
2015          *
2016          * This is basically the same as getFullUrl(), but in the case of external
2017          * interwikis, we send the user to a landing page, to prevent possible
2018          * phishing attacks and the like.
2019          *
2020          * @note Uses current protocol by default, since technically relative urls
2021          *   aren't allowed in redirects per HTTP spec, so this is not suitable for
2022          *   places where the url gets cached, as might pollute between
2023          *   https and non-https users.
2024          * @see self::getLocalURL for the arguments.
2025          * @param array|string $query
2026          * @param string $proto Protocol type to use in URL
2027          * @return string A url suitable to use in an HTTP location header.
2028          */
2029         public function getFullUrlForRedirect( $query = '', $proto = PROTO_CURRENT ) {
2030                 $target = $this;
2031                 if ( $this->isExternal() ) {
2032                         $target = SpecialPage::getTitleFor(
2033                                 'GoToInterwiki',
2034                                 $this->getPrefixedDBkey()
2035                         );
2036                 }
2037                 return $target->getFullURL( $query, false, $proto );
2038         }
2039
2040         /**
2041          * Get a URL with no fragment or server name (relative URL) from a Title object.
2042          * If this page is generated with action=render, however,
2043          * $wgServer is prepended to make an absolute URL.
2044          *
2045          * @see self::getFullURL to always get an absolute URL.
2046          * @see self::getLinkURL to always get a URL that's the simplest URL that will be
2047          *  valid to link, locally, to the current Title.
2048          * @see self::newFromText to produce a Title object.
2049          *
2050          * @param string|string[] $query An optional query string,
2051          *   not used for interwiki links. Can be specified as an associative array as well,
2052          *   e.g., [ 'action' => 'edit' ] (keys and values will be URL-escaped).
2053          *   Some query patterns will trigger various shorturl path replacements.
2054          * @param string|string[]|bool $query2 An optional secondary query array. This one MUST
2055          *   be an array. If a string is passed it will be interpreted as a deprecated
2056          *   variant argument and urlencoded into a variant= argument.
2057          *   This second query argument will be added to the $query
2058          *   The second parameter is deprecated since 1.19. Pass it as a key,value
2059          *   pair in the first parameter array instead.
2060          *
2061          * @return string String of the URL.
2062          */
2063         public function getLocalURL( $query = '', $query2 = false ) {
2064                 global $wgArticlePath, $wgScript, $wgServer, $wgRequest;
2065
2066                 $query = self::fixUrlQueryArgs( $query, $query2 );
2067
2068                 $interwiki = self::getInterwikiLookup()->fetch( $this->mInterwiki );
2069                 if ( $interwiki ) {
2070                         $namespace = $this->getNsText();
2071                         if ( $namespace != '' ) {
2072                                 # Can this actually happen? Interwikis shouldn't be parsed.
2073                                 # Yes! It can in interwiki transclusion. But... it probably shouldn't.
2074                                 $namespace .= ':';
2075                         }
2076                         $url = $interwiki->getURL( $namespace . $this->mDbkeyform );
2077                         $url = wfAppendQuery( $url, $query );
2078                 } else {
2079                         $dbkey = wfUrlencode( $this->getPrefixedDBkey() );
2080                         if ( $query == '' ) {
2081                                 $url = str_replace( '$1', $dbkey, $wgArticlePath );
2082                                 // Avoid PHP 7.1 warning from passing $this by reference
2083                                 $titleRef = $this;
2084                                 Hooks::run( 'GetLocalURL::Article', [ &$titleRef, &$url ] );
2085                         } else {
2086                                 global $wgVariantArticlePath, $wgActionPaths;
2087                                 $url = false;
2088                                 $matches = [];
2089
2090                                 $articlePaths = PathRouter::getActionPaths( $wgActionPaths, $wgArticlePath );
2091
2092                                 if ( $articlePaths
2093                                         && preg_match( '/^(.*&|)action=([^&]*)(&(.*)|)$/', $query, $matches )
2094                                 ) {
2095                                         $action = urldecode( $matches[2] );
2096                                         if ( isset( $articlePaths[$action] ) ) {
2097                                                 $query = $matches[1];
2098                                                 if ( isset( $matches[4] ) ) {
2099                                                         $query .= $matches[4];
2100                                                 }
2101                                                 $url = str_replace( '$1', $dbkey, $articlePaths[$action] );
2102                                                 if ( $query != '' ) {
2103                                                         $url = wfAppendQuery( $url, $query );
2104                                                 }
2105                                         }
2106                                 }
2107
2108                                 if ( $url === false
2109                                         && $wgVariantArticlePath
2110                                         && preg_match( '/^variant=([^&]*)$/', $query, $matches )
2111                                         && $this->getPageLanguage()->equals(
2112                                                 MediaWikiServices::getInstance()->getContentLanguage() )
2113                                         && $this->getPageLanguage()->hasVariants()
2114                                 ) {
2115                                         $variant = urldecode( $matches[1] );
2116                                         if ( $this->getPageLanguage()->hasVariant( $variant ) ) {
2117                                                 // Only do the variant replacement if the given variant is a valid
2118                                                 // variant for the page's language.
2119                                                 $url = str_replace( '$2', urlencode( $variant ), $wgVariantArticlePath );
2120                                                 $url = str_replace( '$1', $dbkey, $url );
2121                                         }
2122                                 }
2123
2124                                 if ( $url === false ) {
2125                                         if ( $query == '-' ) {
2126                                                 $query = '';
2127                                         }
2128                                         $url = "{$wgScript}?title={$dbkey}&{$query}";
2129                                 }
2130                         }
2131                         // Avoid PHP 7.1 warning from passing $this by reference
2132                         $titleRef = $this;
2133                         Hooks::run( 'GetLocalURL::Internal', [ &$titleRef, &$url, $query ] );
2134
2135                         // @todo FIXME: This causes breakage in various places when we
2136                         // actually expected a local URL and end up with dupe prefixes.
2137                         if ( $wgRequest->getVal( 'action' ) == 'render' ) {
2138                                 $url = $wgServer . $url;
2139                         }
2140                 }
2141                 // Avoid PHP 7.1 warning from passing $this by reference
2142                 $titleRef = $this;
2143                 Hooks::run( 'GetLocalURL', [ &$titleRef, &$url, $query ] );
2144                 return $url;
2145         }
2146
2147         /**
2148          * Get a URL that's the simplest URL that will be valid to link, locally,
2149          * to the current Title.  It includes the fragment, but does not include
2150          * the server unless action=render is used (or the link is external).  If
2151          * there's a fragment but the prefixed text is empty, we just return a link
2152          * to the fragment.
2153          *
2154          * The result obviously should not be URL-escaped, but does need to be
2155          * HTML-escaped if it's being output in HTML.
2156          *
2157          * @param string|string[] $query
2158          * @param bool $query2
2159          * @param string|int|bool $proto A PROTO_* constant on how the URL should be expanded,
2160          *                               or false (default) for no expansion
2161          * @see self::getLocalURL for the arguments.
2162          * @return string The URL
2163          */
2164         public function getLinkURL( $query = '', $query2 = false, $proto = false ) {
2165                 if ( $this->isExternal() || $proto !== false ) {
2166                         $ret = $this->getFullURL( $query, $query2, $proto );
2167                 } elseif ( $this->getPrefixedText() === '' && $this->hasFragment() ) {
2168                         $ret = $this->getFragmentForURL();
2169                 } else {
2170                         $ret = $this->getLocalURL( $query, $query2 ) . $this->getFragmentForURL();
2171                 }
2172                 return $ret;
2173         }
2174
2175         /**
2176          * Get the URL form for an internal link.
2177          * - Used in various CDN-related code, in case we have a different
2178          * internal hostname for the server from the exposed one.
2179          *
2180          * This uses $wgInternalServer to qualify the path, or $wgServer
2181          * if $wgInternalServer is not set. If the server variable used is
2182          * protocol-relative, the URL will be expanded to http://
2183          *
2184          * @see self::getLocalURL for the arguments.
2185          * @param string|string[] $query
2186          * @param string|bool $query2 Deprecated
2187          * @return string The URL
2188          */
2189         public function getInternalURL( $query = '', $query2 = false ) {
2190                 global $wgInternalServer, $wgServer;
2191                 $query = self::fixUrlQueryArgs( $query, $query2 );
2192                 $server = $wgInternalServer !== false ? $wgInternalServer : $wgServer;
2193                 $url = wfExpandUrl( $server . $this->getLocalURL( $query ), PROTO_HTTP );
2194                 // Avoid PHP 7.1 warning from passing $this by reference
2195                 $titleRef = $this;
2196                 Hooks::run( 'GetInternalURL', [ &$titleRef, &$url, $query ] );
2197                 return $url;
2198         }
2199
2200         /**
2201          * Get the URL for a canonical link, for use in things like IRC and
2202          * e-mail notifications. Uses $wgCanonicalServer and the
2203          * GetCanonicalURL hook.
2204          *
2205          * NOTE: Unlike getInternalURL(), the canonical URL includes the fragment
2206          *
2207          * @see self::getLocalURL for the arguments.
2208          * @param string|string[] $query
2209          * @param string|bool $query2 Deprecated
2210          * @return string The URL
2211          * @since 1.18
2212          */
2213         public function getCanonicalURL( $query = '', $query2 = false ) {
2214                 $query = self::fixUrlQueryArgs( $query, $query2 );
2215                 $url = wfExpandUrl( $this->getLocalURL( $query ) . $this->getFragmentForURL(), PROTO_CANONICAL );
2216                 // Avoid PHP 7.1 warning from passing $this by reference
2217                 $titleRef = $this;
2218                 Hooks::run( 'GetCanonicalURL', [ &$titleRef, &$url, $query ] );
2219                 return $url;
2220         }
2221
2222         /**
2223          * Get the edit URL for this Title
2224          *
2225          * @return string The URL, or a null string if this is an interwiki link
2226          */
2227         public function getEditURL() {
2228                 if ( $this->isExternal() ) {
2229                         return '';
2230                 }
2231                 $s = $this->getLocalURL( 'action=edit' );
2232
2233                 return $s;
2234         }
2235
2236         /**
2237          * Can $user perform $action on this page?
2238          * This skips potentially expensive cascading permission checks
2239          * as well as avoids expensive error formatting
2240          *
2241          * Suitable for use for nonessential UI controls in common cases, but
2242          * _not_ for functional access control.
2243          *
2244          * May provide false positives, but should never provide a false negative.
2245          *
2246          * @param string $action Action that permission needs to be checked for
2247          * @param User|null $user User to check (since 1.19); $wgUser will be used if not provided.
2248          *
2249          * @return bool
2250          * @throws Exception
2251          *
2252          * @deprecated since 1.33,
2253          * use MediaWikiServices::getInstance()->getPermissionManager()->quickUserCan(..) instead
2254          *
2255          */
2256         public function quickUserCan( $action, $user = null ) {
2257                 return $this->userCan( $action, $user, false );
2258         }
2259
2260         /**
2261          * Can $user perform $action on this page?
2262          *
2263          * @param string $action Action that permission needs to be checked for
2264          * @param User|null $user User to check (since 1.19); $wgUser will be used if not
2265          *   provided.
2266          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2267          *
2268          * @return bool
2269          * @throws Exception
2270          *
2271          * @deprecated since 1.33,
2272          * use MediaWikiServices::getInstance()->getPermissionManager()->userCan(..) instead
2273          *
2274          */
2275         public function userCan( $action, $user = null, $rigor = PermissionManager::RIGOR_SECURE ) {
2276                 if ( !$user instanceof User ) {
2277                         global $wgUser;
2278                         $user = $wgUser;
2279                 }
2280
2281                 // TODO: this is for b/c, eventually will be removed
2282                 if ( $rigor === true ) {
2283                         $rigor = PermissionManager::RIGOR_SECURE; // b/c
2284                 } elseif ( $rigor === false ) {
2285                         $rigor = PermissionManager::RIGOR_QUICK; // b/c
2286                 }
2287
2288                 return MediaWikiServices::getInstance()->getPermissionManager()
2289                         ->userCan( $action, $user, $this, $rigor );
2290         }
2291
2292         /**
2293          * Can $user perform $action on this page?
2294          *
2295          * @todo FIXME: This *does not* check throttles (User::pingLimiter()).
2296          *
2297          * @param string $action Action that permission needs to be checked for
2298          * @param User $user User to check
2299          * @param string $rigor One of (quick,full,secure)
2300          *   - quick  : does cheap permission checks from replica DBs (usable for GUI creation)
2301          *   - full   : does cheap and expensive checks possibly from a replica DB
2302          *   - secure : does cheap and expensive checks, using the master as needed
2303          * @param array $ignoreErrors Array of Strings Set this to a list of message keys
2304          *   whose corresponding errors may be ignored.
2305          *
2306          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
2307          * @throws Exception
2308          *
2309          * @deprecated since 1.33,
2310          * use MediaWikiServices::getInstance()->getPermissionManager()->getPermissionErrors()
2311          *
2312          */
2313         public function getUserPermissionsErrors(
2314                 $action, $user, $rigor = PermissionManager::RIGOR_SECURE, $ignoreErrors = []
2315         ) {
2316                 // TODO: this is for b/c, eventually will be removed
2317                 if ( $rigor === true ) {
2318                         $rigor = PermissionManager::RIGOR_SECURE; // b/c
2319                 } elseif ( $rigor === false ) {
2320                         $rigor = PermissionManager::RIGOR_QUICK; // b/c
2321                 }
2322
2323                 return MediaWikiServices::getInstance()->getPermissionManager()
2324                         ->getPermissionErrors( $action, $user, $this, $rigor, $ignoreErrors );
2325         }
2326
2327         /**
2328          * Get a filtered list of all restriction types supported by this wiki.
2329          * @param bool $exists True to get all restriction types that apply to
2330          * titles that do exist, False for all restriction types that apply to
2331          * titles that do not exist
2332          * @return array
2333          */
2334         public static function getFilteredRestrictionTypes( $exists = true ) {
2335                 global $wgRestrictionTypes;
2336                 $types = $wgRestrictionTypes;
2337                 if ( $exists ) {
2338                         # Remove the create restriction for existing titles
2339                         $types = array_diff( $types, [ 'create' ] );
2340                 } else {
2341                         # Only the create and upload restrictions apply to non-existing titles
2342                         $types = array_intersect( $types, [ 'create', 'upload' ] );
2343                 }
2344                 return $types;
2345         }
2346
2347         /**
2348          * Returns restriction types for the current Title
2349          *
2350          * @return array Applicable restriction types
2351          */
2352         public function getRestrictionTypes() {
2353                 if ( $this->isSpecialPage() ) {
2354                         return [];
2355                 }
2356
2357                 $types = self::getFilteredRestrictionTypes( $this->exists() );
2358
2359                 if ( $this->mNamespace != NS_FILE ) {
2360                         # Remove the upload restriction for non-file titles
2361                         $types = array_diff( $types, [ 'upload' ] );
2362                 }
2363
2364                 Hooks::run( 'TitleGetRestrictionTypes', [ $this, &$types ] );
2365
2366                 wfDebug( __METHOD__ . ': applicable restrictions to [[' .
2367                         $this->getPrefixedText() . ']] are {' . implode( ',', $types ) . "}\n" );
2368
2369                 return $types;
2370         }
2371
2372         /**
2373          * Is this title subject to title protection?
2374          * Title protection is the one applied against creation of such title.
2375          *
2376          * @return array|bool An associative array representing any existent title
2377          *   protection, or false if there's none.
2378          */
2379         public function getTitleProtection() {
2380                 $protection = $this->getTitleProtectionInternal();
2381                 if ( $protection ) {
2382                         if ( $protection['permission'] == 'sysop' ) {
2383                                 $protection['permission'] = 'editprotected'; // B/C
2384                         }
2385                         if ( $protection['permission'] == 'autoconfirmed' ) {
2386                                 $protection['permission'] = 'editsemiprotected'; // B/C
2387                         }
2388                 }
2389                 return $protection;
2390         }
2391
2392         /**
2393          * Fetch title protection settings
2394          *
2395          * To work correctly, $this->loadRestrictions() needs to have access to the
2396          * actual protections in the database without munging 'sysop' =>
2397          * 'editprotected' and 'autoconfirmed' => 'editsemiprotected'. Other
2398          * callers probably want $this->getTitleProtection() instead.
2399          *
2400          * @return array|bool
2401          */
2402         protected function getTitleProtectionInternal() {
2403                 // Can't protect pages in special namespaces
2404                 if ( $this->mNamespace < 0 ) {
2405                         return false;
2406                 }
2407
2408                 // Can't protect pages that exist.
2409                 if ( $this->exists() ) {
2410                         return false;
2411                 }
2412
2413                 if ( $this->mTitleProtection === null ) {
2414                         $dbr = wfGetDB( DB_REPLICA );
2415                         $commentStore = CommentStore::getStore();
2416                         $commentQuery = $commentStore->getJoin( 'pt_reason' );
2417                         $res = $dbr->select(
2418                                 [ 'protected_titles' ] + $commentQuery['tables'],
2419                                 [
2420                                         'user' => 'pt_user',
2421                                         'expiry' => 'pt_expiry',
2422                                         'permission' => 'pt_create_perm'
2423                                 ] + $commentQuery['fields'],
2424                                 [ 'pt_namespace' => $this->mNamespace, 'pt_title' => $this->mDbkeyform ],
2425                                 __METHOD__,
2426                                 [],
2427                                 $commentQuery['joins']
2428                         );
2429
2430                         // fetchRow returns false if there are no rows.
2431                         $row = $dbr->fetchRow( $res );
2432                         if ( $row ) {
2433                                 $this->mTitleProtection = [
2434                                         'user' => $row['user'],
2435                                         'expiry' => $dbr->decodeExpiry( $row['expiry'] ),
2436                                         'permission' => $row['permission'],
2437                                         'reason' => $commentStore->getComment( 'pt_reason', $row )->text,
2438                                 ];
2439                         } else {
2440                                 $this->mTitleProtection = false;
2441                         }
2442                 }
2443                 return $this->mTitleProtection;
2444         }
2445
2446         /**
2447          * Remove any title protection due to page existing
2448          */
2449         public function deleteTitleProtection() {
2450                 $dbw = wfGetDB( DB_MASTER );
2451
2452                 $dbw->delete(
2453                         'protected_titles',
2454                         [ 'pt_namespace' => $this->mNamespace, 'pt_title' => $this->mDbkeyform ],
2455                         __METHOD__
2456                 );
2457                 $this->mTitleProtection = false;
2458         }
2459
2460         /**
2461          * Is this page "semi-protected" - the *only* protection levels are listed
2462          * in $wgSemiprotectedRestrictionLevels?
2463          *
2464          * @param string $action Action to check (default: edit)
2465          * @return bool
2466          */
2467         public function isSemiProtected( $action = 'edit' ) {
2468                 global $wgSemiprotectedRestrictionLevels;
2469
2470                 $restrictions = $this->getRestrictions( $action );
2471                 $semi = $wgSemiprotectedRestrictionLevels;
2472                 if ( !$restrictions || !$semi ) {
2473                         // Not protected, or all protection is full protection
2474                         return false;
2475                 }
2476
2477                 // Remap autoconfirmed to editsemiprotected for BC
2478                 foreach ( array_keys( $semi, 'autoconfirmed' ) as $key ) {
2479                         $semi[$key] = 'editsemiprotected';
2480                 }
2481                 foreach ( array_keys( $restrictions, 'autoconfirmed' ) as $key ) {
2482                         $restrictions[$key] = 'editsemiprotected';
2483                 }
2484
2485                 return !array_diff( $restrictions, $semi );
2486         }
2487
2488         /**
2489          * Does the title correspond to a protected article?
2490          *
2491          * @param string $action The action the page is protected from,
2492          * by default checks all actions.
2493          * @return bool
2494          */
2495         public function isProtected( $action = '' ) {
2496                 global $wgRestrictionLevels;
2497
2498                 $restrictionTypes = $this->getRestrictionTypes();
2499
2500                 # Special pages have inherent protection
2501                 if ( $this->isSpecialPage() ) {
2502                         return true;
2503                 }
2504
2505                 # Check regular protection levels
2506                 foreach ( $restrictionTypes as $type ) {
2507                         if ( $action == $type || $action == '' ) {
2508                                 $r = $this->getRestrictions( $type );
2509                                 foreach ( $wgRestrictionLevels as $level ) {
2510                                         if ( in_array( $level, $r ) && $level != '' ) {
2511                                                 return true;
2512                                         }
2513                                 }
2514                         }
2515                 }
2516
2517                 return false;
2518         }
2519
2520         /**
2521          * Determines if $user is unable to edit this page because it has been protected
2522          * by $wgNamespaceProtection.
2523          *
2524          * @deprecated since 1.34 Don't use this function in new code.
2525          * @param User $user User object to check permissions
2526          * @return bool
2527          */
2528         public function isNamespaceProtected( User $user ) {
2529                 global $wgNamespaceProtection;
2530
2531                 if ( isset( $wgNamespaceProtection[$this->mNamespace] ) ) {
2532                         $permissionManager = MediaWikiServices::getInstance()->getPermissionManager();
2533                         foreach ( (array)$wgNamespaceProtection[$this->mNamespace] as $right ) {
2534                                 if ( !$permissionManager->userHasRight( $user, $right ) ) {
2535                                         return true;
2536                                 }
2537                         }
2538                 }
2539                 return false;
2540         }
2541
2542         /**
2543          * Cascading protection: Return true if cascading restrictions apply to this page, false if not.
2544          *
2545          * @return bool If the page is subject to cascading restrictions.
2546          */
2547         public function isCascadeProtected() {
2548                 list( $sources, /* $restrictions */ ) = $this->getCascadeProtectionSources( false );
2549                 return ( $sources > 0 );
2550         }
2551
2552         /**
2553          * Determines whether cascading protection sources have already been loaded from
2554          * the database.
2555          *
2556          * @param bool $getPages True to check if the pages are loaded, or false to check
2557          * if the status is loaded.
2558          * @return bool Whether or not the specified information has been loaded
2559          * @since 1.23
2560          */
2561         public function areCascadeProtectionSourcesLoaded( $getPages = true ) {
2562                 return $getPages ? $this->mCascadeSources !== null : $this->mHasCascadingRestrictions !== null;
2563         }
2564
2565         /**
2566          * Cascading protection: Get the source of any cascading restrictions on this page.
2567          *
2568          * @param bool $getPages Whether or not to retrieve the actual pages
2569          *        that the restrictions have come from and the actual restrictions
2570          *        themselves.
2571          * @return array Two elements: First is an array of Title objects of the
2572          *        pages from which cascading restrictions have come, false for
2573          *        none, or true if such restrictions exist but $getPages was not
2574          *        set. Second is an array like that returned by
2575          *        Title::getAllRestrictions(), or an empty array if $getPages is
2576          *        false.
2577          */
2578         public function getCascadeProtectionSources( $getPages = true ) {
2579                 $pagerestrictions = [];
2580
2581                 if ( $this->mCascadeSources !== null && $getPages ) {
2582                         return [ $this->mCascadeSources, $this->mCascadingRestrictions ];
2583                 } elseif ( $this->mHasCascadingRestrictions !== null && !$getPages ) {
2584                         return [ $this->mHasCascadingRestrictions, $pagerestrictions ];
2585                 }
2586
2587                 $dbr = wfGetDB( DB_REPLICA );
2588
2589                 if ( $this->mNamespace == NS_FILE ) {
2590                         $tables = [ 'imagelinks', 'page_restrictions' ];
2591                         $where_clauses = [
2592                                 'il_to' => $this->mDbkeyform,
2593                                 'il_from=pr_page',
2594                                 'pr_cascade' => 1
2595                         ];
2596                 } else {
2597                         $tables = [ 'templatelinks', 'page_restrictions' ];
2598                         $where_clauses = [
2599                                 'tl_namespace' => $this->mNamespace,
2600                                 'tl_title' => $this->mDbkeyform,
2601                                 'tl_from=pr_page',
2602                                 'pr_cascade' => 1
2603                         ];
2604                 }
2605
2606                 if ( $getPages ) {
2607                         $cols = [ 'pr_page', 'page_namespace', 'page_title',
2608                                 'pr_expiry', 'pr_type', 'pr_level' ];
2609                         $where_clauses[] = 'page_id=pr_page';
2610                         $tables[] = 'page';
2611                 } else {
2612                         $cols = [ 'pr_expiry' ];
2613                 }
2614
2615                 $res = $dbr->select( $tables, $cols, $where_clauses, __METHOD__ );
2616
2617                 $sources = $getPages ? [] : false;
2618                 $now = wfTimestampNow();
2619
2620                 foreach ( $res as $row ) {
2621                         $expiry = $dbr->decodeExpiry( $row->pr_expiry );
2622                         if ( $expiry > $now ) {
2623                                 if ( $getPages ) {
2624                                         $page_id = $row->pr_page;
2625                                         $page_ns = $row->page_namespace;
2626                                         $page_title = $row->page_title;
2627                                         $sources[$page_id] = self::makeTitle( $page_ns, $page_title );
2628                                         # Add groups needed for each restriction type if its not already there
2629                                         # Make sure this restriction type still exists
2630
2631                                         if ( !isset( $pagerestrictions[$row->pr_type] ) ) {
2632                                                 $pagerestrictions[$row->pr_type] = [];
2633                                         }
2634
2635                                         if (
2636                                                 isset( $pagerestrictions[$row->pr_type] )
2637                                                 && !in_array( $row->pr_level, $pagerestrictions[$row->pr_type] )
2638                                         ) {
2639                                                 $pagerestrictions[$row->pr_type][] = $row->pr_level;
2640                                         }
2641                                 } else {
2642                                         $sources = true;
2643                                 }
2644                         }
2645                 }
2646
2647                 if ( $getPages ) {
2648                         $this->mCascadeSources = $sources;
2649                         $this->mCascadingRestrictions = $pagerestrictions;
2650                 } else {
2651                         $this->mHasCascadingRestrictions = $sources;
2652                 }
2653
2654                 return [ $sources, $pagerestrictions ];
2655         }
2656
2657         /**
2658          * Accessor for mRestrictionsLoaded
2659          *
2660          * @return bool Whether or not the page's restrictions have already been
2661          * loaded from the database
2662          * @since 1.23
2663          */
2664         public function areRestrictionsLoaded() {
2665                 return $this->mRestrictionsLoaded;
2666         }
2667
2668         /**
2669          * Accessor/initialisation for mRestrictions
2670          *
2671          * @param string $action Action that permission needs to be checked for
2672          * @return array Restriction levels needed to take the action. All levels are
2673          *     required. Note that restriction levels are normally user rights, but 'sysop'
2674          *     and 'autoconfirmed' are also allowed for backwards compatibility. These should
2675          *     be mapped to 'editprotected' and 'editsemiprotected' respectively.
2676          */
2677         public function getRestrictions( $action ) {
2678                 if ( !$this->mRestrictionsLoaded ) {
2679                         $this->loadRestrictions();
2680                 }
2681                 return $this->mRestrictions[$action] ?? [];
2682         }
2683
2684         /**
2685          * Accessor/initialisation for mRestrictions
2686          *
2687          * @return array Keys are actions, values are arrays as returned by
2688          *     Title::getRestrictions()
2689          * @since 1.23
2690          */
2691         public function getAllRestrictions() {
2692                 if ( !$this->mRestrictionsLoaded ) {
2693                         $this->loadRestrictions();
2694                 }
2695                 return $this->mRestrictions;
2696         }
2697
2698         /**
2699          * Get the expiry time for the restriction against a given action
2700          *
2701          * @param string $action
2702          * @return string|bool 14-char timestamp, or 'infinity' if the page is protected forever
2703          *     or not protected at all, or false if the action is not recognised.
2704          */
2705         public function getRestrictionExpiry( $action ) {
2706                 if ( !$this->mRestrictionsLoaded ) {
2707                         $this->loadRestrictions();
2708                 }
2709                 return $this->mRestrictionsExpiry[$action] ?? false;
2710         }
2711
2712         /**
2713          * Returns cascading restrictions for the current article
2714          *
2715          * @return bool
2716          */
2717         function areRestrictionsCascading() {
2718                 if ( !$this->mRestrictionsLoaded ) {
2719                         $this->loadRestrictions();
2720                 }
2721
2722                 return $this->mCascadeRestriction;
2723         }
2724
2725         /**
2726          * Compiles list of active page restrictions from both page table (pre 1.10)
2727          * and page_restrictions table for this existing page.
2728          * Public for usage by LiquidThreads.
2729          *
2730          * @param array $rows Array of db result objects
2731          * @param string|null $oldFashionedRestrictions Comma-separated set of permission keys
2732          * indicating who can move or edit the page from the page table, (pre 1.10) rows.
2733          * Edit and move sections are separated by a colon
2734          * Example: "edit=autoconfirmed,sysop:move=sysop"
2735          */
2736         public function loadRestrictionsFromRows( $rows, $oldFashionedRestrictions = null ) {
2737                 // This function will only read rows from a table that we migrated away
2738                 // from before adding READ_LATEST support to loadRestrictions, so we
2739                 // don't need to support reading from DB_MASTER here.
2740                 $dbr = wfGetDB( DB_REPLICA );
2741
2742                 $restrictionTypes = $this->getRestrictionTypes();
2743
2744                 foreach ( $restrictionTypes as $type ) {
2745                         $this->mRestrictions[$type] = [];
2746                         $this->mRestrictionsExpiry[$type] = 'infinity';
2747                 }
2748
2749                 $this->mCascadeRestriction = false;
2750
2751                 # Backwards-compatibility: also load the restrictions from the page record (old format).
2752                 if ( $oldFashionedRestrictions !== null ) {
2753                         $this->mOldRestrictions = $oldFashionedRestrictions;
2754                 }
2755
2756                 if ( $this->mOldRestrictions === false ) {
2757                         $linkCache = MediaWikiServices::getInstance()->getLinkCache();
2758                         $linkCache->addLinkObj( $this ); # in case we already had an article ID
2759                         $this->mOldRestrictions = $linkCache->getGoodLinkFieldObj( $this, 'restrictions' );
2760                 }
2761
2762                 if ( $this->mOldRestrictions != '' ) {
2763                         foreach ( explode( ':', trim( $this->mOldRestrictions ) ) as $restrict ) {
2764                                 $temp = explode( '=', trim( $restrict ) );
2765                                 if ( count( $temp ) == 1 ) {
2766                                         // old old format should be treated as edit/move restriction
2767                                         $this->mRestrictions['edit'] = explode( ',', trim( $temp[0] ) );
2768                                         $this->mRestrictions['move'] = explode( ',', trim( $temp[0] ) );
2769                                 } else {
2770                                         $restriction = trim( $temp[1] );
2771                                         if ( $restriction != '' ) { // some old entries are empty
2772                                                 $this->mRestrictions[$temp[0]] = explode( ',', $restriction );
2773                                         }
2774                                 }
2775                         }
2776                 }
2777
2778                 if ( count( $rows ) ) {
2779                         # Current system - load second to make them override.
2780                         $now = wfTimestampNow();
2781
2782                         # Cycle through all the restrictions.
2783                         foreach ( $rows as $row ) {
2784                                 // Don't take care of restrictions types that aren't allowed
2785                                 if ( !in_array( $row->pr_type, $restrictionTypes ) ) {
2786                                         continue;
2787                                 }
2788
2789                                 $expiry = $dbr->decodeExpiry( $row->pr_expiry );
2790
2791                                 // Only apply the restrictions if they haven't expired!
2792                                 if ( !$expiry || $expiry > $now ) {
2793                                         $this->mRestrictionsExpiry[$row->pr_type] = $expiry;
2794                                         $this->mRestrictions[$row->pr_type] = explode( ',', trim( $row->pr_level ) );
2795
2796                                         $this->mCascadeRestriction |= $row->pr_cascade;
2797                                 }
2798                         }
2799                 }
2800
2801                 $this->mRestrictionsLoaded = true;
2802         }
2803
2804         /**
2805          * Load restrictions from the page_restrictions table
2806          *
2807          * @param string|null $oldFashionedRestrictions Comma-separated set of permission keys
2808          * indicating who can move or edit the page from the page table, (pre 1.10) rows.
2809          * Edit and move sections are separated by a colon
2810          * Example: "edit=autoconfirmed,sysop:move=sysop"
2811          * @param int $flags A bit field. If self::READ_LATEST is set, skip replicas and read
2812          *  from the master DB.
2813          */
2814         public function loadRestrictions( $oldFashionedRestrictions = null, $flags = 0 ) {
2815                 $readLatest = DBAccessObjectUtils::hasFlags( $flags, self::READ_LATEST );
2816                 if ( $this->mRestrictionsLoaded && !$readLatest ) {
2817                         return;
2818                 }
2819
2820                 $id = $this->getArticleID( $flags );
2821                 if ( $id ) {
2822                         $fname = __METHOD__;
2823                         $loadRestrictionsFromDb = function ( IDatabase $dbr ) use ( $fname, $id ) {
2824                                 return iterator_to_array(
2825                                         $dbr->select(
2826                                                 'page_restrictions',
2827                                                 [ 'pr_type', 'pr_expiry', 'pr_level', 'pr_cascade' ],
2828                                                 [ 'pr_page' => $id ],
2829                                                 $fname
2830                                         )
2831                                 );
2832                         };
2833
2834                         if ( $readLatest ) {
2835                                 $dbr = wfGetDB( DB_MASTER );
2836                                 $rows = $loadRestrictionsFromDb( $dbr );
2837                         } else {
2838                                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
2839                                 $rows = $cache->getWithSetCallback(
2840                                         // Page protections always leave a new null revision
2841                                         $cache->makeKey( 'page-restrictions', 'v1', $id, $this->getLatestRevID() ),
2842                                         $cache::TTL_DAY,
2843                                         function ( $curValue, &$ttl, array &$setOpts ) use ( $loadRestrictionsFromDb ) {
2844                                                 $dbr = wfGetDB( DB_REPLICA );
2845
2846                                                 $setOpts += Database::getCacheSetOptions( $dbr );
2847                                                 $lb = MediaWikiServices::getInstance()->getDBLoadBalancer();
2848                                                 if ( $lb->hasOrMadeRecentMasterChanges() ) {
2849                                                         // @TODO: cleanup Title cache and caller assumption mess in general
2850                                                         $ttl = WANObjectCache::TTL_UNCACHEABLE;
2851                                                 }
2852
2853                                                 return $loadRestrictionsFromDb( $dbr );
2854                                         }
2855                                 );
2856                         }
2857
2858                         $this->loadRestrictionsFromRows( $rows, $oldFashionedRestrictions );
2859                 } else {
2860                         $title_protection = $this->getTitleProtectionInternal();
2861
2862                         if ( $title_protection ) {
2863                                 $now = wfTimestampNow();
2864                                 $expiry = wfGetDB( DB_REPLICA )->decodeExpiry( $title_protection['expiry'] );
2865
2866                                 if ( !$expiry || $expiry > $now ) {
2867                                         // Apply the restrictions
2868                                         $this->mRestrictionsExpiry['create'] = $expiry;
2869                                         $this->mRestrictions['create'] =
2870                                                 explode( ',', trim( $title_protection['permission'] ) );
2871                                 } else { // Get rid of the old restrictions
2872                                         $this->mTitleProtection = false;
2873                                 }
2874                         } else {
2875                                 $this->mRestrictionsExpiry['create'] = 'infinity';
2876                         }
2877                         $this->mRestrictionsLoaded = true;
2878                 }
2879         }
2880
2881         /**
2882          * Flush the protection cache in this object and force reload from the database.
2883          * This is used when updating protection from WikiPage::doUpdateRestrictions().
2884          */
2885         public function flushRestrictions() {
2886                 $this->mRestrictionsLoaded = false;
2887                 $this->mTitleProtection = null;
2888         }
2889
2890         /**
2891          * Purge expired restrictions from the page_restrictions table
2892          *
2893          * This will purge no more than $wgUpdateRowsPerQuery page_restrictions rows
2894          */
2895         static function purgeExpiredRestrictions() {
2896                 if ( wfReadOnly() ) {
2897                         return;
2898                 }
2899
2900                 DeferredUpdates::addUpdate( new AtomicSectionUpdate(
2901                         wfGetDB( DB_MASTER ),
2902                         __METHOD__,
2903                         function ( IDatabase $dbw, $fname ) {
2904                                 $config = MediaWikiServices::getInstance()->getMainConfig();
2905                                 $ids = $dbw->selectFieldValues(
2906                                         'page_restrictions',
2907                                         'pr_id',
2908                                         [ 'pr_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ],
2909                                         $fname,
2910                                         [ 'LIMIT' => $config->get( 'UpdateRowsPerQuery' ) ] // T135470
2911                                 );
2912                                 if ( $ids ) {
2913                                         $dbw->delete( 'page_restrictions', [ 'pr_id' => $ids ], $fname );
2914                                 }
2915                         }
2916                 ) );
2917
2918                 DeferredUpdates::addUpdate( new AtomicSectionUpdate(
2919                         wfGetDB( DB_MASTER ),
2920                         __METHOD__,
2921                         function ( IDatabase $dbw, $fname ) {
2922                                 $dbw->delete(
2923                                         'protected_titles',
2924                                         [ 'pt_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ],
2925                                         $fname
2926                                 );
2927                         }
2928                 ) );
2929         }
2930
2931         /**
2932          * Does this have subpages?  (Warning, usually requires an extra DB query.)
2933          *
2934          * @return bool
2935          */
2936         public function hasSubpages() {
2937                 if (
2938                         !MediaWikiServices::getInstance()->getNamespaceInfo()->
2939                                 hasSubpages( $this->mNamespace )
2940                 ) {
2941                         # Duh
2942                         return false;
2943                 }
2944
2945                 # We dynamically add a member variable for the purpose of this method
2946                 # alone to cache the result.  There's no point in having it hanging
2947                 # around uninitialized in every Title object; therefore we only add it
2948                 # if needed and don't declare it statically.
2949                 if ( $this->mHasSubpages === null ) {
2950                         $this->mHasSubpages = false;
2951                         $subpages = $this->getSubpages( 1 );
2952                         if ( $subpages instanceof TitleArray ) {
2953                                 $this->mHasSubpages = (bool)$subpages->current();
2954                         }
2955                 }
2956
2957                 return $this->mHasSubpages;
2958         }
2959
2960         /**
2961          * Get all subpages of this page.
2962          *
2963          * @param int $limit Maximum number of subpages to fetch; -1 for no limit
2964          * @return TitleArray|array TitleArray, or empty array if this page's namespace
2965          *  doesn't allow subpages
2966          */
2967         public function getSubpages( $limit = -1 ) {
2968                 if (
2969                         !MediaWikiServices::getInstance()->getNamespaceInfo()->
2970                                 hasSubpages( $this->mNamespace )
2971                 ) {
2972                         return [];
2973                 }
2974
2975                 $dbr = wfGetDB( DB_REPLICA );
2976                 $conds = [ 'page_namespace' => $this->mNamespace ];
2977                 $conds[] = 'page_title ' . $dbr->buildLike( $this->mDbkeyform . '/', $dbr->anyString() );
2978                 $options = [];
2979                 if ( $limit > -1 ) {
2980                         $options['LIMIT'] = $limit;
2981                 }
2982                 return TitleArray::newFromResult(
2983                         $dbr->select( 'page',
2984                                 [ 'page_id', 'page_namespace', 'page_title', 'page_is_redirect' ],
2985                                 $conds,
2986                                 __METHOD__,
2987                                 $options
2988                         )
2989                 );
2990         }
2991
2992         /**
2993          * Is there a version of this page in the deletion archive?
2994          *
2995          * @return int The number of archived revisions
2996          */
2997         public function isDeleted() {
2998                 if ( $this->mNamespace < 0 ) {
2999                         $n = 0;
3000                 } else {
3001                         $dbr = wfGetDB( DB_REPLICA );
3002
3003                         $n = $dbr->selectField( 'archive', 'COUNT(*)',
3004                                 [ 'ar_namespace' => $this->mNamespace, 'ar_title' => $this->mDbkeyform ],
3005                                 __METHOD__
3006                         );
3007                         if ( $this->mNamespace == NS_FILE ) {
3008                                 $n += $dbr->selectField( 'filearchive', 'COUNT(*)',
3009                                         [ 'fa_name' => $this->mDbkeyform ],
3010                                         __METHOD__
3011                                 );
3012                         }
3013                 }
3014                 return (int)$n;
3015         }
3016
3017         /**
3018          * Is there a version of this page in the deletion archive?
3019          *
3020          * @return bool
3021          */
3022         public function isDeletedQuick() {
3023                 if ( $this->mNamespace < 0 ) {
3024                         return false;
3025                 }
3026                 $dbr = wfGetDB( DB_REPLICA );
3027                 $deleted = (bool)$dbr->selectField( 'archive', '1',
3028                         [ 'ar_namespace' => $this->mNamespace, 'ar_title' => $this->mDbkeyform ],
3029                         __METHOD__
3030                 );
3031                 if ( !$deleted && $this->mNamespace == NS_FILE ) {
3032                         $deleted = (bool)$dbr->selectField( 'filearchive', '1',
3033                                 [ 'fa_name' => $this->mDbkeyform ],
3034                                 __METHOD__
3035                         );
3036                 }
3037                 return $deleted;
3038         }
3039
3040         /**
3041          * Get the article ID for this Title from the link cache,
3042          * adding it if necessary
3043          *
3044          * @param int $flags Either a bitfield of class READ_* constants or GAID_FOR_UPDATE
3045          * @return int The ID
3046          */
3047         public function getArticleID( $flags = 0 ) {
3048                 if ( $this->mNamespace < 0 ) {
3049                         $this->mArticleID = 0;
3050
3051                         return $this->mArticleID;
3052                 }
3053
3054                 $linkCache = MediaWikiServices::getInstance()->getLinkCache();
3055                 if ( $flags & self::GAID_FOR_UPDATE ) {
3056                         $oldUpdate = $linkCache->forUpdate( true );
3057                         $linkCache->clearLink( $this );
3058                         $this->mArticleID = $linkCache->addLinkObj( $this );
3059                         $linkCache->forUpdate( $oldUpdate );
3060                 } elseif ( DBAccessObjectUtils::hasFlags( $flags, self::READ_LATEST ) ) {
3061                         $this->mArticleID = (int)$this->loadFieldFromDB( 'page_id', $flags );
3062                 } elseif ( $this->mArticleID == -1 ) {
3063                         $this->mArticleID = $linkCache->addLinkObj( $this );
3064                 }
3065
3066                 return $this->mArticleID;
3067         }
3068
3069         /**
3070          * Is this an article that is a redirect page?
3071          * Uses link cache, adding it if necessary
3072          *
3073          * @param int $flags Either a bitfield of class READ_* constants or GAID_FOR_UPDATE
3074          * @return bool
3075          */
3076         public function isRedirect( $flags = 0 ) {
3077                 if ( DBAccessObjectUtils::hasFlags( $flags, self::READ_LATEST ) ) {
3078                         $this->mRedirect = (bool)$this->loadFieldFromDB( 'page_is_redirect', $flags );
3079                 } else {
3080                         if ( $this->mRedirect !== null ) {
3081                                 return $this->mRedirect;
3082                         } elseif ( !$this->getArticleID( $flags ) ) {
3083                                 $this->mRedirect = false;
3084
3085                                 return $this->mRedirect;
3086                         }
3087
3088                         $linkCache = MediaWikiServices::getInstance()->getLinkCache();
3089                         $linkCache->addLinkObj( $this ); // in case we already had an article ID
3090                         // Note that LinkCache returns null if it thinks the page does not exist;
3091                         // always trust the state of LinkCache over that of this Title instance.
3092                         $this->mRedirect = (bool)$linkCache->getGoodLinkFieldObj( $this, 'redirect' );
3093                 }
3094
3095                 return $this->mRedirect;
3096         }
3097
3098         /**
3099          * What is the length of this page?
3100          * Uses link cache, adding it if necessary
3101          *
3102          * @param int $flags Either a bitfield of class READ_* constants or GAID_FOR_UPDATE
3103          * @return int
3104          */
3105         public function getLength( $flags = 0 ) {
3106                 if ( DBAccessObjectUtils::hasFlags( $flags, self::READ_LATEST ) ) {
3107                         $this->mLength = (int)$this->loadFieldFromDB( 'page_len', $flags );
3108                 } else {
3109                         if ( $this->mLength != -1 ) {
3110                                 return $this->mLength;
3111                         } elseif ( !$this->getArticleID( $flags ) ) {
3112                                 $this->mLength = 0;
3113                                 return $this->mLength;
3114                         }
3115
3116                         $linkCache = MediaWikiServices::getInstance()->getLinkCache();
3117                         $linkCache->addLinkObj( $this ); // in case we already had an article ID
3118                         // Note that LinkCache returns null if it thinks the page does not exist;
3119                         // always trust the state of LinkCache over that of this Title instance.
3120                         $this->mLength = (int)$linkCache->getGoodLinkFieldObj( $this, 'length' );
3121                 }
3122
3123                 return $this->mLength;
3124         }
3125
3126         /**
3127          * What is the page_latest field for this page?
3128          *
3129          * @param int $flags Either a bitfield of class READ_* constants or GAID_FOR_UPDATE
3130          * @return int Int or 0 if the page doesn't exist
3131          */
3132         public function getLatestRevID( $flags = 0 ) {
3133                 if ( DBAccessObjectUtils::hasFlags( $flags, self::READ_LATEST ) ) {
3134                         $this->mLatestID = (int)$this->loadFieldFromDB( 'page_latest', $flags );
3135                 } else {
3136                         if ( $this->mLatestID !== false ) {
3137                                 return (int)$this->mLatestID;
3138                         } elseif ( !$this->getArticleID( $flags ) ) {
3139                                 $this->mLatestID = 0;
3140
3141                                 return $this->mLatestID;
3142                         }
3143
3144                         $linkCache = MediaWikiServices::getInstance()->getLinkCache();
3145                         $linkCache->addLinkObj( $this ); // in case we already had an article ID
3146                         // Note that LinkCache returns null if it thinks the page does not exist;
3147                         // always trust the state of LinkCache over that of this Title instance.
3148                         $this->mLatestID = (int)$linkCache->getGoodLinkFieldObj( $this, 'revision' );
3149                 }
3150
3151                 return $this->mLatestID;
3152         }
3153
3154         /**
3155          * Inject a page ID, reset DB-loaded fields, and clear the link cache for this title
3156          *
3157          * This can be called on page insertion to allow loading of the new page_id without
3158          * having to create a new Title instance. Likewise with deletion.
3159          *
3160          * @note This overrides Title::setContentModel()
3161          *
3162          * @param int|bool $id Page ID, 0 for non-existant, or false for "unknown" (lazy-load)
3163          */
3164         public function resetArticleID( $id ) {
3165                 if ( $id === false ) {
3166                         $this->mArticleID = -1;
3167                 } else {
3168                         $this->mArticleID = (int)$id;
3169                 }
3170                 $this->mRestrictionsLoaded = false;
3171                 $this->mRestrictions = [];
3172                 $this->mOldRestrictions = false;
3173                 $this->mRedirect = null;
3174                 $this->mLength = -1;
3175                 $this->mLatestID = false;
3176                 $this->mContentModel = false;
3177                 $this->mForcedContentModel = false;
3178                 $this->mEstimateRevisions = null;
3179                 $this->mPageLanguage = null;
3180                 $this->mDbPageLanguage = false;
3181                 $this->mIsBigDeletion = null;
3182
3183                 MediaWikiServices::getInstance()->getLinkCache()->clearLink( $this );
3184         }
3185
3186         public static function clearCaches() {
3187                 $linkCache = MediaWikiServices::getInstance()->getLinkCache();
3188                 $linkCache->clear();
3189
3190                 $titleCache = self::getTitleCache();
3191                 $titleCache->clear();
3192         }
3193
3194         /**
3195          * Capitalize a text string for a title if it belongs to a namespace that capitalizes
3196          *
3197          * @param string $text Containing title to capitalize
3198          * @param int $ns Namespace index, defaults to NS_MAIN
3199          * @return string Containing capitalized title
3200          */
3201         public static function capitalize( $text, $ns = NS_MAIN ) {
3202                 $services = MediaWikiServices::getInstance();
3203                 if ( $services->getNamespaceInfo()->isCapitalized( $ns ) ) {
3204                         return $services->getContentLanguage()->ucfirst( $text );
3205                 } else {
3206                         return $text;
3207                 }
3208         }
3209
3210         /**
3211          * Secure and split - main initialisation function for this object
3212          *
3213          * Assumes that mDbkeyform has been set, and is urldecoded
3214          * and uses underscores, but not otherwise munged.  This function
3215          * removes illegal characters, splits off the interwiki and
3216          * namespace prefixes, sets the other forms, and canonicalizes
3217          * everything.
3218          *
3219          * @throws MalformedTitleException On invalid titles
3220          * @return bool True on success
3221          */
3222         private function secureAndSplit() {
3223                 // @note: splitTitleString() is a temporary hack to allow MediaWikiTitleCodec to share
3224                 //        the parsing code with Title, while avoiding massive refactoring.
3225                 // @todo: get rid of secureAndSplit, refactor parsing code.
3226                 // @note: getTitleParser() returns a TitleParser implementation which does not have a
3227                 //        splitTitleString method, but the only implementation (MediaWikiTitleCodec) does
3228                 /** @var MediaWikiTitleCodec $titleCodec */
3229                 $titleCodec = MediaWikiServices::getInstance()->getTitleParser();
3230                 '@phan-var MediaWikiTitleCodec $titleCodec';
3231                 // MalformedTitleException can be thrown here
3232                 $parts = $titleCodec->splitTitleString( $this->mDbkeyform, $this->mDefaultNamespace );
3233
3234                 # Fill fields
3235                 $this->setFragment( '#' . $parts['fragment'] );
3236                 $this->mInterwiki = $parts['interwiki'];
3237                 $this->mLocalInterwiki = $parts['local_interwiki'];
3238                 $this->mNamespace = $parts['namespace'];
3239                 $this->mUserCaseDBKey = $parts['user_case_dbkey'];
3240
3241                 $this->mDbkeyform = $parts['dbkey'];
3242                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
3243                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
3244
3245                 # We already know that some pages won't be in the database!
3246                 if ( $this->isExternal() || $this->isSpecialPage() ) {
3247                         $this->mArticleID = 0;
3248                 }
3249
3250                 return true;
3251         }
3252
3253         /**
3254          * Get an array of Title objects linking to this Title
3255          * Also stores the IDs in the link cache.
3256          *
3257          * WARNING: do not use this function on arbitrary user-supplied titles!
3258          * On heavily-used templates it will max out the memory.
3259          *
3260          * @param array $options May be FOR UPDATE
3261          * @param string $table Table name
3262          * @param string $prefix Fields prefix
3263          * @return Title[] Array of Title objects linking here
3264          */
3265         public function getLinksTo( $options = [], $table = 'pagelinks', $prefix = 'pl' ) {
3266                 if ( count( $options ) > 0 ) {
3267                         $db = wfGetDB( DB_MASTER );
3268                 } else {
3269                         $db = wfGetDB( DB_REPLICA );
3270                 }
3271
3272                 $res = $db->select(
3273                         [ 'page', $table ],
3274                         self::getSelectFields(),
3275                         [
3276                                 "{$prefix}_from=page_id",
3277                                 "{$prefix}_namespace" => $this->mNamespace,
3278                                 "{$prefix}_title" => $this->mDbkeyform ],
3279                         __METHOD__,
3280                         $options
3281                 );
3282
3283                 $retVal = [];
3284                 if ( $res->numRows() ) {
3285                         $linkCache = MediaWikiServices::getInstance()->getLinkCache();
3286                         foreach ( $res as $row ) {
3287                                 $titleObj = self::makeTitle( $row->page_namespace, $row->page_title );
3288                                 if ( $titleObj ) {
3289                                         $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3290                                         $retVal[] = $titleObj;
3291                                 }
3292                         }
3293                 }
3294                 return $retVal;
3295         }
3296
3297         /**
3298          * Get an array of Title objects using this Title as a template
3299          * Also stores the IDs in the link cache.
3300          *
3301          * WARNING: do not use this function on arbitrary user-supplied titles!
3302          * On heavily-used templates it will max out the memory.
3303          *
3304          * @param array $options Query option to Database::select()
3305          * @return Title[] Array of Title the Title objects linking here
3306          */
3307         public function getTemplateLinksTo( $options = [] ) {
3308                 return $this->getLinksTo( $options, 'templatelinks', 'tl' );
3309         }
3310
3311         /**
3312          * Get an array of Title objects linked from this Title
3313          * Also stores the IDs in the link cache.
3314          *
3315          * WARNING: do not use this function on arbitrary user-supplied titles!
3316          * On heavily-used templates it will max out the memory.
3317          *
3318          * @param array $options Query option to Database::select()
3319          * @param string $table Table name
3320          * @param string $prefix Fields prefix
3321          * @return array Array of Title objects linking here
3322          */
3323         public function getLinksFrom( $options = [], $table = 'pagelinks', $prefix = 'pl' ) {
3324                 $id = $this->getArticleID();
3325
3326                 # If the page doesn't exist; there can't be any link from this page
3327                 if ( !$id ) {
3328                         return [];
3329                 }
3330
3331                 $db = wfGetDB( DB_REPLICA );
3332
3333                 $blNamespace = "{$prefix}_namespace";
3334                 $blTitle = "{$prefix}_title";
3335
3336                 $pageQuery = WikiPage::getQueryInfo();
3337                 $res = $db->select(
3338                         [ $table, 'nestpage' => $pageQuery['tables'] ],
3339                         array_merge(
3340                                 [ $blNamespace, $blTitle ],
3341                                 $pageQuery['fields']
3342                         ),
3343                         [ "{$prefix}_from" => $id ],
3344                         __METHOD__,
3345                         $options,
3346                         [ 'nestpage' => [
3347                                 'LEFT JOIN',
3348                                 [ "page_namespace=$blNamespace", "page_title=$blTitle" ]
3349                         ] ] + $pageQuery['joins']
3350                 );
3351
3352                 $retVal = [];
3353                 $linkCache = MediaWikiServices::getInstance()->getLinkCache();
3354                 foreach ( $res as $row ) {
3355                         if ( $row->page_id ) {
3356                                 $titleObj = self::newFromRow( $row );
3357                         } else {
3358                                 $titleObj = self::makeTitle( $row->$blNamespace, $row->$blTitle );
3359                                 $linkCache->addBadLinkObj( $titleObj );
3360                         }
3361                         $retVal[] = $titleObj;
3362                 }
3363
3364                 return $retVal;
3365         }
3366
3367         /**
3368          * Get an array of Title objects used on this Title as a template
3369          * Also stores the IDs in the link cache.
3370          *
3371          * WARNING: do not use this function on arbitrary user-supplied titles!
3372          * On heavily-used templates it will max out the memory.
3373          *
3374          * @param array $options May be FOR UPDATE
3375          * @return Title[] Array of Title the Title objects used here
3376          */
3377         public function getTemplateLinksFrom( $options = [] ) {
3378                 return $this->getLinksFrom( $options, 'templatelinks', 'tl' );
3379         }
3380
3381         /**
3382          * Get an array of Title objects referring to non-existent articles linked
3383          * from this page.
3384          *
3385          * @todo check if needed (used only in SpecialBrokenRedirects.php, and
3386          *   should use redirect table in this case).
3387          * @return Title[] Array of Title the Title objects
3388          */
3389         public function getBrokenLinksFrom() {
3390                 if ( $this->getArticleID() == 0 ) {
3391                         # All links from article ID 0 are false positives
3392                         return [];
3393                 }
3394
3395                 $dbr = wfGetDB( DB_REPLICA );
3396                 $res = $dbr->select(
3397                         [ 'page', 'pagelinks' ],
3398                         [ 'pl_namespace', 'pl_title' ],
3399                         [
3400                                 'pl_from' => $this->getArticleID(),
3401                                 'page_namespace IS NULL'
3402                         ],
3403                         __METHOD__, [],
3404                         [
3405                                 'page' => [
3406                                         'LEFT JOIN',
3407                                         [ 'pl_namespace=page_namespace', 'pl_title=page_title' ]
3408                                 ]
3409                         ]
3410                 );
3411
3412                 $retVal = [];
3413                 foreach ( $res as $row ) {
3414                         $retVal[] = self::makeTitle( $row->pl_namespace, $row->pl_title );
3415                 }
3416                 return $retVal;
3417         }
3418
3419         /**
3420          * Get a list of URLs to purge from the CDN cache when this
3421          * page changes
3422          *
3423          * @return string[] Array of String the URLs
3424          */
3425         public function getCdnUrls() {
3426                 $urls = [
3427                         $this->getInternalURL(),
3428                         $this->getInternalURL( 'action=history' )
3429                 ];
3430
3431                 $pageLang = $this->getPageLanguage();
3432                 if ( $pageLang->hasVariants() ) {
3433                         $variants = $pageLang->getVariants();
3434                         foreach ( $variants as $vCode ) {
3435                                 $urls[] = $this->getInternalURL( $vCode );
3436                         }
3437                 }
3438
3439                 // If we are looking at a css/js user subpage, purge the action=raw.
3440                 if ( $this->isUserJsConfigPage() ) {
3441                         $urls[] = $this->getInternalURL( 'action=raw&ctype=text/javascript' );
3442                 } elseif ( $this->isUserJsonConfigPage() ) {
3443                         $urls[] = $this->getInternalURL( 'action=raw&ctype=application/json' );
3444                 } elseif ( $this->isUserCssConfigPage() ) {
3445                         $urls[] = $this->getInternalURL( 'action=raw&ctype=text/css' );
3446                 }
3447
3448                 Hooks::run( 'TitleSquidURLs', [ $this, &$urls ] );
3449                 return $urls;
3450         }
3451
3452         /**
3453          * Purge all applicable CDN URLs
3454          */
3455         public function purgeSquid() {
3456                 DeferredUpdates::addUpdate(
3457                         new CdnCacheUpdate( $this->getCdnUrls() ),
3458                         DeferredUpdates::PRESEND
3459                 );
3460         }
3461
3462         /**
3463          * Check whether a given move operation would be valid.
3464          * Returns true if ok, or a getUserPermissionsErrors()-like array otherwise
3465          *
3466          * @deprecated since 1.25, use MovePage's methods instead
3467          * @param Title &$nt The new title
3468          * @param bool $auth Whether to check user permissions (uses $wgUser)
3469          * @param string $reason Is the log summary of the move, used for spam checking
3470          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3471          */
3472         public function isValidMoveOperation( &$nt, $auth = true, $reason = '' ) {
3473                 wfDeprecated( __METHOD__, '1.25' );
3474
3475                 global $wgUser;
3476
3477                 if ( !( $nt instanceof Title ) ) {
3478                         // Normally we'd add this to $errors, but we'll get
3479                         // lots of syntax errors if $nt is not an object
3480                         return [ [ 'badtitletext' ] ];
3481                 }
3482
3483                 $mp = MediaWikiServices::getInstance()->getMovePageFactory()->newMovePage( $this, $nt );
3484                 $errors = $mp->isValidMove()->getErrorsArray();
3485                 if ( $auth ) {
3486                         $errors = wfMergeErrorArrays(
3487                                 $errors,
3488                                 $mp->checkPermissions( $wgUser, $reason )->getErrorsArray()
3489                         );
3490                 }
3491
3492                 return $errors ?: true;
3493         }
3494
3495         /**
3496          * Move a title to a new location
3497          *
3498          * @deprecated since 1.25, use the MovePage class instead
3499          * @param Title &$nt The new title
3500          * @param bool $auth Indicates whether $wgUser's permissions
3501          *  should be checked
3502          * @param string $reason The reason for the move
3503          * @param bool $createRedirect Whether to create a redirect from the old title to the new title.
3504          *  Ignored if the user doesn't have the suppressredirect right.
3505          * @param array $changeTags Applied to the entry in the move log and redirect page revision
3506          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3507          */
3508         public function moveTo( &$nt, $auth = true, $reason = '', $createRedirect = true,
3509                 array $changeTags = []
3510         ) {
3511                 wfDeprecated( __METHOD__, '1.25' );
3512
3513                 global $wgUser;
3514
3515                 $mp = MediaWikiServices::getInstance()->getMovePageFactory()->newMovePage( $this, $nt );
3516                 $method = $auth ? 'moveIfAllowed' : 'move';
3517                 /** @var Status $status */
3518                 $status = $mp->$method( $wgUser, $reason, $createRedirect, $changeTags );
3519                 if ( $status->isOK() ) {
3520                         return true;
3521                 } else {
3522                         return $status->getErrorsArray();
3523                 }
3524         }
3525
3526         /**
3527          * Move this page's subpages to be subpages of $nt
3528          *
3529          * @deprecated since 1.34, use MovePage instead
3530          * @param Title $nt Move target
3531          * @param bool $auth Whether $wgUser's permissions should be checked
3532          * @param string $reason The reason for the move
3533          * @param bool $createRedirect Whether to create redirects from the old subpages to
3534          *     the new ones Ignored if the user doesn't have the 'suppressredirect' right
3535          * @param array $changeTags Applied to the entry in the move log and redirect page revision
3536          * @return array Array with old page titles as keys, and strings (new page titles) or
3537          *     getUserPermissionsErrors()-like arrays (errors) as values, or a
3538          *     getUserPermissionsErrors()-like error array with numeric indices if
3539          *     no pages were moved
3540          */
3541         public function moveSubpages( $nt, $auth = true, $reason = '', $createRedirect = true,
3542                 array $changeTags = []
3543         ) {
3544                 wfDeprecated( __METHOD__, '1.34' );
3545
3546                 global $wgUser;
3547
3548                 $mp = new MovePage( $this, $nt );
3549                 $method = $auth ? 'moveSubpagesIfAllowed' : 'moveSubpages';
3550                 /** @var Status $result */
3551                 $result = $mp->$method( $wgUser, $reason, $createRedirect, $changeTags );
3552
3553                 if ( !$result->isOK() ) {
3554                         return $result->getErrorsArray();
3555                 }
3556
3557                 $retval = [];
3558                 foreach ( $result->getValue() as $key => $status ) {
3559                         /** @var Status $status */
3560                         if ( $status->isOK() ) {
3561                                 $retval[$key] = $status->getValue();
3562                         } else {
3563                                 $retval[$key] = $status->getErrorsArray();
3564                         }
3565                 }
3566                 return $retval;
3567         }
3568
3569         /**
3570          * Locks the page row and check if this page is single revision redirect
3571          *
3572          * This updates the cached fields of this instance via Title::loadFromRow()
3573          *
3574          * @return bool
3575          */
3576         public function isSingleRevRedirect() {
3577                 global $wgContentHandlerUseDB;
3578
3579                 $dbw = wfGetDB( DB_MASTER );
3580
3581                 # Is it a redirect?
3582                 $fields = [ 'page_is_redirect', 'page_latest', 'page_id' ];
3583                 if ( $wgContentHandlerUseDB ) {
3584                         $fields[] = 'page_content_model';
3585                 }
3586
3587                 $row = $dbw->selectRow( 'page',
3588                         $fields,
3589                         $this->pageCond(),
3590                         __METHOD__,
3591                         [ 'FOR UPDATE' ]
3592                 );
3593                 # Cache some fields we may want
3594                 $this->mArticleID = $row ? intval( $row->page_id ) : 0;
3595                 $this->mRedirect = $row ? (bool)$row->page_is_redirect : false;
3596                 $this->mLatestID = $row ? intval( $row->page_latest ) : false;
3597                 $this->mContentModel = $row && isset( $row->page_content_model )
3598                         ? strval( $row->page_content_model )
3599                         : false;
3600
3601                 if ( !$this->mRedirect ) {
3602                         return false;
3603                 }
3604                 # Does the article have a history?
3605                 $row = $dbw->selectField( [ 'page', 'revision' ],
3606                         'rev_id',
3607                         [ 'page_namespace' => $this->mNamespace,
3608                                 'page_title' => $this->mDbkeyform,
3609                                 'page_id=rev_page',
3610                                 'page_latest != rev_id'
3611                         ],
3612                         __METHOD__,
3613                         [ 'FOR UPDATE' ]
3614                 );
3615                 # Return true if there was no history
3616                 return ( $row === false );
3617         }
3618
3619         /**
3620          * Checks if $this can be moved to a given Title
3621          * - Selects for update, so don't call it unless you mean business
3622          *
3623          * @deprecated since 1.25, use MovePage's methods instead
3624          * @param Title $nt The new title to check
3625          * @return bool
3626          */
3627         public function isValidMoveTarget( $nt ) {
3628                 wfDeprecated( __METHOD__, '1.25' );
3629
3630                 # Is it an existing file?
3631                 if ( $nt->getNamespace() == NS_FILE ) {
3632                         $file = MediaWikiServices::getInstance()->getRepoGroup()->getLocalRepo()
3633                                 ->newFile( $nt );
3634                         $file->load( File::READ_LATEST );
3635                         if ( $file->exists() ) {
3636                                 wfDebug( __METHOD__ . ": file exists\n" );
3637                                 return false;
3638                         }
3639                 }
3640                 # Is it a redirect with no history?
3641                 if ( !$nt->isSingleRevRedirect() ) {
3642                         wfDebug( __METHOD__ . ": not a one-rev redirect\n" );
3643                         return false;
3644                 }
3645                 # Get the article text
3646                 $rev = Revision::newFromTitle( $nt, false, Revision::READ_LATEST );
3647                 if ( !is_object( $rev ) ) {
3648                         return false;
3649                 }
3650                 $content = $rev->getContent();
3651                 # Does the redirect point to the source?
3652                 # Or is it a broken self-redirect, usually caused by namespace collisions?
3653                 $redirTitle = $content ? $content->getRedirectTarget() : null;
3654
3655                 if ( $redirTitle ) {
3656                         if ( $redirTitle->getPrefixedDBkey() != $this->getPrefixedDBkey() &&
3657                                 $redirTitle->getPrefixedDBkey() != $nt->getPrefixedDBkey() ) {
3658                                 wfDebug( __METHOD__ . ": redirect points to other page\n" );
3659                                 return false;
3660                         } else {
3661                                 return true;
3662                         }
3663                 } else {
3664                         # Fail safe (not a redirect after all. strange.)
3665                         wfDebug( __METHOD__ . ": failsafe: database sais " . $nt->getPrefixedDBkey() .
3666                                                 " is a redirect, but it doesn't contain a valid redirect.\n" );
3667                         return false;
3668                 }
3669         }
3670
3671         /**
3672          * Get categories to which this Title belongs and return an array of
3673          * categories' names.
3674          *
3675          * @return array Array of parents in the form:
3676          *     $parent => $currentarticle
3677          */
3678         public function getParentCategories() {
3679                 $data = [];
3680
3681                 $titleKey = $this->getArticleID();
3682
3683                 if ( $titleKey === 0 ) {
3684                         return $data;
3685                 }
3686
3687                 $dbr = wfGetDB( DB_REPLICA );
3688
3689                 $res = $dbr->select(
3690                         'categorylinks',
3691                         'cl_to',
3692                         [ 'cl_from' => $titleKey ],
3693                         __METHOD__
3694                 );
3695
3696                 if ( $res->numRows() > 0 ) {
3697                         $contLang = MediaWikiServices::getInstance()->getContentLanguage();
3698                         foreach ( $res as $row ) {
3699                                 // $data[] = Title::newFromText( $contLang->getNsText ( NS_CATEGORY ).':'.$row->cl_to);
3700                                 $data[$contLang->getNsText( NS_CATEGORY ) . ':' . $row->cl_to] =
3701                                         $this->getFullText();
3702                         }
3703                 }
3704                 return $data;
3705         }
3706
3707         /**
3708          * Get a tree of parent categories
3709          *
3710          * @param array $children Array with the children in the keys, to check for circular refs
3711          * @return array Tree of parent categories
3712          */
3713         public function getParentCategoryTree( $children = [] ) {
3714                 $stack = [];
3715                 $parents = $this->getParentCategories();
3716
3717                 if ( $parents ) {
3718                         foreach ( $parents as $parent => $current ) {
3719                                 if ( array_key_exists( $parent, $children ) ) {
3720                                         # Circular reference
3721                                         $stack[$parent] = [];
3722                                 } else {
3723                                         $nt = self::newFromText( $parent );
3724                                         if ( $nt ) {
3725                                                 $stack[$parent] = $nt->getParentCategoryTree( $children + [ $parent => 1 ] );
3726                                         }
3727                                 }
3728                         }
3729                 }
3730
3731                 return $stack;
3732         }
3733
3734         /**
3735          * Get an associative array for selecting this title from
3736          * the "page" table
3737          *
3738          * @return array Array suitable for the $where parameter of DB::select()
3739          */
3740         public function pageCond() {
3741                 if ( $this->mArticleID > 0 ) {
3742                         // PK avoids secondary lookups in InnoDB, shouldn't hurt other DBs
3743                         return [ 'page_id' => $this->mArticleID ];
3744                 } else {
3745                         return [ 'page_namespace' => $this->mNamespace, 'page_title' => $this->mDbkeyform ];
3746                 }
3747         }
3748
3749         /**
3750          * Get next/previous revision ID relative to another revision ID
3751          * @param int $revId Revision ID. Get the revision that was before this one.
3752          * @param int $flags Bitfield of class READ_* constants
3753          * @param string $dir 'next' or 'prev'
3754          * @return int|bool New revision ID, or false if none exists
3755          */
3756         private function getRelativeRevisionID( $revId, $flags, $dir ) {
3757                 $rl = MediaWikiServices::getInstance()->getRevisionLookup();
3758                 $rev = $rl->getRevisionById( $revId, $flags );
3759                 if ( !$rev ) {
3760                         return false;
3761                 }
3762
3763                 $oldRev = ( $dir === 'next' )
3764                         ? $rl->getNextRevision( $rev, $flags )
3765                         : $rl->getPreviousRevision( $rev, $flags );
3766
3767                 return $oldRev ? $oldRev->getId() : false;
3768         }
3769
3770         /**
3771          * Get the revision ID of the previous revision
3772          *
3773          * @deprecated since 1.34, use RevisionLookup::getPreviousRevision
3774          * @param int $revId Revision ID. Get the revision that was before this one.
3775          * @param int $flags Bitfield of class READ_* constants
3776          * @return int|bool Old revision ID, or false if none exists
3777          */
3778         public function getPreviousRevisionID( $revId, $flags = 0 ) {
3779                 return $this->getRelativeRevisionID( $revId, $flags, 'prev' );
3780         }
3781
3782         /**
3783          * Get the revision ID of the next revision
3784          *
3785          * @deprecated since 1.34, use RevisionLookup::getNextRevision
3786          * @param int $revId Revision ID. Get the revision that was after this one.
3787          * @param int $flags Bitfield of class READ_* constants
3788          * @return int|bool Next revision ID, or false if none exists
3789          */
3790         public function getNextRevisionID( $revId, $flags = 0 ) {
3791                 return $this->getRelativeRevisionID( $revId, $flags, 'next' );
3792         }
3793
3794         /**
3795          * Get the first revision of the page
3796          *
3797          * @param int $flags Bitfield of class READ_* constants
3798          * @return Revision|null If page doesn't exist
3799          */
3800         public function getFirstRevision( $flags = 0 ) {
3801                 $pageId = $this->getArticleID( $flags );
3802                 if ( $pageId ) {
3803                         $flags |= ( $flags & self::GAID_FOR_UPDATE ) ? self::READ_LATEST : 0; // b/c
3804                         list( $index, $options ) = DBAccessObjectUtils::getDBOptions( $flags );
3805                         $revQuery = Revision::getQueryInfo();
3806                         $row = wfGetDB( $index )->selectRow(
3807                                 $revQuery['tables'], $revQuery['fields'],
3808                                 [ 'rev_page' => $pageId ],
3809                                 __METHOD__,
3810                                 array_merge(
3811                                         [
3812                                                 'ORDER BY' => 'rev_timestamp ASC, rev_id ASC',
3813                                                 'IGNORE INDEX' => [ 'revision' => 'rev_timestamp' ], // See T159319
3814                                         ],
3815                                         $options
3816                                 ),
3817                                 $revQuery['joins']
3818                         );
3819                         if ( $row ) {
3820                                 return new Revision( $row, 0, $this );
3821                         }
3822                 }
3823                 return null;
3824         }
3825
3826         /**
3827          * Get the oldest revision timestamp of this page
3828          *
3829          * @param int $flags Bitfield of class READ_* constants
3830          * @return string|null MW timestamp
3831          */
3832         public function getEarliestRevTime( $flags = 0 ) {
3833                 $rev = $this->getFirstRevision( $flags );
3834                 return $rev ? $rev->getTimestamp() : null;
3835         }
3836
3837         /**
3838          * Check if this is a new page
3839          *
3840          * @return bool
3841          */
3842         public function isNewPage() {
3843                 $dbr = wfGetDB( DB_REPLICA );
3844                 return (bool)$dbr->selectField( 'page', 'page_is_new', $this->pageCond(), __METHOD__ );
3845         }
3846
3847         /**
3848          * Check whether the number of revisions of this page surpasses $wgDeleteRevisionsLimit
3849          *
3850          * @return bool
3851          */
3852         public function isBigDeletion() {
3853                 global $wgDeleteRevisionsLimit;
3854
3855                 if ( !$wgDeleteRevisionsLimit ) {
3856                         return false;
3857                 }
3858
3859                 if ( $this->mIsBigDeletion === null ) {
3860                         $dbr = wfGetDB( DB_REPLICA );
3861
3862                         $revCount = $dbr->selectRowCount(
3863                                 'revision',
3864                                 '1',
3865                                 [ 'rev_page' => $this->getArticleID() ],
3866                                 __METHOD__,
3867                                 [ 'LIMIT' => $wgDeleteRevisionsLimit + 1 ]
3868                         );
3869
3870                         $this->mIsBigDeletion = $revCount > $wgDeleteRevisionsLimit;
3871                 }
3872
3873                 return $this->mIsBigDeletion;
3874         }
3875
3876         /**
3877          * Get the approximate revision count of this page.
3878          *
3879          * @return int
3880          */
3881         public function estimateRevisionCount() {
3882                 if ( !$this->exists() ) {
3883                         return 0;
3884                 }
3885
3886                 if ( $this->mEstimateRevisions === null ) {
3887                         $dbr = wfGetDB( DB_REPLICA );
3888                         $this->mEstimateRevisions = $dbr->estimateRowCount( 'revision', '*',
3889                                 [ 'rev_page' => $this->getArticleID() ], __METHOD__ );
3890                 }
3891
3892                 return $this->mEstimateRevisions;
3893         }
3894
3895         /**
3896          * Get the number of revisions between the given revision.
3897          * Used for diffs and other things that really need it.
3898          *
3899          * @param int|Revision $old Old revision or rev ID (first before range)
3900          * @param int|Revision $new New revision or rev ID (first after range)
3901          * @param int|null $max Limit of Revisions to count, will be incremented to detect truncations
3902          * @return int Number of revisions between these revisions.
3903          */
3904         public function countRevisionsBetween( $old, $new, $max = null ) {
3905                 if ( !( $old instanceof Revision ) ) {
3906                         $old = Revision::newFromTitle( $this, (int)$old );
3907                 }
3908                 if ( !( $new instanceof Revision ) ) {
3909                         $new = Revision::newFromTitle( $this, (int)$new );
3910                 }
3911                 if ( !$old || !$new ) {
3912                         return 0; // nothing to compare
3913                 }
3914                 $dbr = wfGetDB( DB_REPLICA );
3915                 $conds = [
3916                         'rev_page' => $this->getArticleID(),
3917                         'rev_timestamp > ' . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
3918                         'rev_timestamp < ' . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
3919                 ];
3920                 if ( $max !== null ) {
3921                         return $dbr->selectRowCount( 'revision', '1',
3922                                 $conds,
3923                                 __METHOD__,
3924                                 [ 'LIMIT' => $max + 1 ] // extra to detect truncation
3925                         );
3926                 } else {
3927                         return (int)$dbr->selectField( 'revision', 'count(*)', $conds, __METHOD__ );
3928                 }
3929         }
3930
3931         /**
3932          * Get the authors between the given revisions or revision IDs.
3933          * Used for diffs and other things that really need it.
3934          *
3935          * @since 1.23
3936          *
3937          * @param int|Revision $old Old revision or rev ID (first before range by default)
3938          * @param int|Revision $new New revision or rev ID (first after range by default)
3939          * @param int $limit Maximum number of authors
3940          * @param string|array $options (Optional): Single option, or an array of options:
3941          *     'include_old' Include $old in the range; $new is excluded.
3942          *     'include_new' Include $new in the range; $old is excluded.
3943          *     'include_both' Include both $old and $new in the range.
3944          *     Unknown option values are ignored.
3945          * @return array|null Names of revision authors in the range; null if not both revisions exist
3946          */
3947         public function getAuthorsBetween( $old, $new, $limit, $options = [] ) {
3948                 if ( !( $old instanceof Revision ) ) {
3949                         $old = Revision::newFromTitle( $this, (int)$old );
3950                 }
3951                 if ( !( $new instanceof Revision ) ) {
3952                         $new = Revision::newFromTitle( $this, (int)$new );
3953                 }
3954                 // XXX: what if Revision objects are passed in, but they don't refer to this title?
3955                 // Add $old->getPage() != $new->getPage() || $old->getPage() != $this->getArticleID()
3956                 // in the sanity check below?
3957                 if ( !$old || !$new ) {
3958                         return null; // nothing to compare
3959                 }
3960                 $authors = [];
3961                 $old_cmp = '>';
3962                 $new_cmp = '<';
3963                 $options = (array)$options;
3964                 if ( in_array( 'include_old', $options ) ) {
3965                         $old_cmp = '>=';
3966                 }
3967                 if ( in_array( 'include_new', $options ) ) {
3968                         $new_cmp = '<=';
3969                 }
3970                 if ( in_array( 'include_both', $options ) ) {
3971                         $old_cmp = '>=';
3972                         $new_cmp = '<=';
3973                 }
3974                 // No DB query needed if $old and $new are the same or successive revisions:
3975                 if ( $old->getId() === $new->getId() ) {
3976                         return ( $old_cmp === '>' && $new_cmp === '<' ) ?
3977                                 [] :
3978                                 [ $old->getUserText( RevisionRecord::RAW ) ];
3979                 } elseif ( $old->getId() === $new->getParentId() ) {
3980                         if ( $old_cmp === '>=' && $new_cmp === '<=' ) {
3981                                 $authors[] = $oldUserText = $old->getUserText( RevisionRecord::RAW );
3982                                 $newUserText = $new->getUserText( RevisionRecord::RAW );
3983                                 if ( $oldUserText != $newUserText ) {
3984                                         $authors[] = $newUserText;
3985                                 }
3986                         } elseif ( $old_cmp === '>=' ) {
3987                                 $authors[] = $old->getUserText( RevisionRecord::RAW );
3988                         } elseif ( $new_cmp === '<=' ) {
3989                                 $authors[] = $new->getUserText( RevisionRecord::RAW );
3990                         }
3991                         return $authors;
3992                 }
3993                 $dbr = wfGetDB( DB_REPLICA );
3994                 $revQuery = Revision::getQueryInfo();
3995                 $authors = $dbr->selectFieldValues(
3996                         $revQuery['tables'],
3997                         $revQuery['fields']['rev_user_text'],
3998                         [
3999                                 'rev_page' => $this->getArticleID(),
4000                                 "rev_timestamp $old_cmp " . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4001                                 "rev_timestamp $new_cmp " . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4002                         ], __METHOD__,
4003                         [ 'DISTINCT', 'LIMIT' => $limit + 1 ], // add one so caller knows it was truncated
4004                         $revQuery['joins']
4005                 );
4006                 return $authors;
4007         }
4008
4009         /**
4010          * Get the number of authors between the given revisions or revision IDs.
4011          * Used for diffs and other things that really need it.
4012          *
4013          * @param int|Revision $old Old revision or rev ID (first before range by default)
4014          * @param int|Revision $new New revision or rev ID (first after range by default)
4015          * @param int $limit Maximum number of authors
4016          * @param string|array $options (Optional): Single option, or an array of options:
4017          *     'include_old' Include $old in the range; $new is excluded.
4018          *     'include_new' Include $new in the range; $old is excluded.
4019          *     'include_both' Include both $old and $new in the range.
4020          *     Unknown option values are ignored.
4021          * @return int Number of revision authors in the range; zero if not both revisions exist
4022          */
4023         public function countAuthorsBetween( $old, $new, $limit, $options = [] ) {
4024                 $authors = $this->getAuthorsBetween( $old, $new, $limit, $options );
4025                 return $authors ? count( $authors ) : 0;
4026         }
4027
4028         /**
4029          * Compare with another title.
4030          *
4031          * @param LinkTarget $title
4032          * @return bool
4033          */
4034         public function equals( LinkTarget $title ) {
4035                 // Note: === is necessary for proper matching of number-like titles.
4036                 return $this->mInterwiki === $title->getInterwiki()
4037                         && $this->mNamespace == $title->getNamespace()
4038                         && $this->mDbkeyform === $title->getDBkey();
4039         }
4040
4041         /**
4042          * Check if this title is a subpage of another title
4043          *
4044          * @param Title $title
4045          * @return bool
4046          */
4047         public function isSubpageOf( Title $title ) {
4048                 return $this->mInterwiki === $title->mInterwiki
4049                         && $this->mNamespace == $title->mNamespace
4050                         && strpos( $this->mDbkeyform, $title->mDbkeyform . '/' ) === 0;
4051         }
4052
4053         /**
4054          * Check if page exists.  For historical reasons, this function simply
4055          * checks for the existence of the title in the page table, and will
4056          * thus return false for interwiki links, special pages and the like.
4057          * If you want to know if a title can be meaningfully viewed, you should
4058          * probably call the isKnown() method instead.
4059          *
4060          * @param int $flags Either a bitfield of class READ_* constants or GAID_FOR_UPDATE
4061          * @return bool
4062          */
4063         public function exists( $flags = 0 ) {
4064                 $exists = $this->getArticleID( $flags ) != 0;
4065                 Hooks::run( 'TitleExists', [ $this, &$exists ] );
4066                 return $exists;
4067         }
4068
4069         /**
4070          * Should links to this title be shown as potentially viewable (i.e. as
4071          * "bluelinks"), even if there's no record by this title in the page
4072          * table?
4073          *
4074          * This function is semi-deprecated for public use, as well as somewhat
4075          * misleadingly named.  You probably just want to call isKnown(), which
4076          * calls this function internally.
4077          *
4078          * (ISSUE: Most of these checks are cheap, but the file existence check
4079          * can potentially be quite expensive.  Including it here fixes a lot of
4080          * existing code, but we might want to add an optional parameter to skip
4081          * it and any other expensive checks.)
4082          *
4083          * @return bool
4084          */
4085         public function isAlwaysKnown() {
4086                 $isKnown = null;
4087
4088                 /**
4089                  * Allows overriding default behavior for determining if a page exists.
4090                  * If $isKnown is kept as null, regular checks happen. If it's
4091                  * a boolean, this value is returned by the isKnown method.
4092                  *
4093                  * @since 1.20
4094                  *
4095                  * @param Title $title
4096                  * @param bool|null $isKnown
4097                  */
4098                 Hooks::run( 'TitleIsAlwaysKnown', [ $this, &$isKnown ] );
4099
4100                 if ( !is_null( $isKnown ) ) {
4101                         return $isKnown;
4102                 }
4103
4104                 if ( $this->isExternal() ) {
4105                         return true; // any interwiki link might be viewable, for all we know
4106                 }
4107
4108                 $services = MediaWikiServices::getInstance();
4109                 switch ( $this->mNamespace ) {
4110                         case NS_MEDIA:
4111                         case NS_FILE:
4112                                 // file exists, possibly in a foreign repo
4113                                 return (bool)$services->getRepoGroup()->findFile( $this );
4114                         case NS_SPECIAL:
4115                                 // valid special page
4116                                 return $services->getSpecialPageFactory()->exists( $this->mDbkeyform );
4117                         case NS_MAIN:
4118                                 // selflink, possibly with fragment
4119                                 return $this->mDbkeyform == '';
4120                         case NS_MEDIAWIKI:
4121                                 // known system message
4122                                 return $this->hasSourceText() !== false;
4123                         default:
4124                                 return false;
4125                 }
4126         }
4127
4128         /**
4129          * Does this title refer to a page that can (or might) be meaningfully
4130          * viewed?  In particular, this function may be used to determine if
4131          * links to the title should be rendered as "bluelinks" (as opposed to
4132          * "redlinks" to non-existent pages).
4133          * Adding something else to this function will cause inconsistency
4134          * since LinkHolderArray calls isAlwaysKnown() and does its own
4135          * page existence check.
4136          *
4137          * @return bool
4138          */
4139         public function isKnown() {
4140                 return $this->isAlwaysKnown() || $this->exists();
4141         }
4142
4143         /**
4144          * Does this page have source text?
4145          *
4146          * @return bool
4147          */
4148         public function hasSourceText() {
4149                 if ( $this->exists() ) {
4150                         return true;
4151                 }
4152
4153                 if ( $this->mNamespace == NS_MEDIAWIKI ) {
4154                         // If the page doesn't exist but is a known system message, default
4155                         // message content will be displayed, same for language subpages-
4156                         // Use always content language to avoid loading hundreds of languages
4157                         // to get the link color.
4158                         $contLang = MediaWikiServices::getInstance()->getContentLanguage();
4159                         list( $name, ) = MessageCache::singleton()->figureMessage(
4160                                 $contLang->lcfirst( $this->getText() )
4161                         );
4162                         $message = wfMessage( $name )->inLanguage( $contLang )->useDatabase( false );
4163                         return $message->exists();
4164                 }
4165
4166                 return false;
4167         }
4168
4169         /**
4170          * Get the default (plain) message contents for an page that overrides an
4171          * interface message key.
4172          *
4173          * Primary use cases:
4174          *
4175          * - Article:
4176          *    - Show default when viewing the page. The Article::getSubstituteContent
4177          *      method displays the default message content, instead of the
4178          *      'noarticletext' placeholder message normally used.
4179          *
4180          * - EditPage:
4181          *    - Title of edit page. When creating an interface message override,
4182          *      the editor is told they are "Editing the page", instead of
4183          *      "Creating the page". (EditPage::setHeaders)
4184          *    - Edit notice. The 'translateinterface' edit notice is shown when creating
4185          *      or editing a an interface message override. (EditPage::showIntro)
4186          *    - Opening the editor. The contents of the localisation message are used
4187          *      as contents of the editor when creating a new page in the MediaWiki
4188          *      namespace. This simplifies the process for editors when "changing"
4189          *      an interface message by creating an override. (EditPage::getContentObject)
4190          *    - Showing a diff. The left-hand side of a diff when an editor is
4191          *      previewing their changes before saving the creation of a page in the
4192          *      MediaWiki namespace. (EditPage::showDiff)
4193          *    - Disallowing a save. When attempting to create a a MediaWiki-namespace
4194          *      page with the proposed content matching the interface message default,
4195          *      the save is rejected, the same way we disallow blank pages from being
4196          *      created. (EditPage::internalAttemptSave)
4197          *
4198          * - ApiEditPage:
4199          *    - Default content, when using the 'prepend' or 'append' feature.
4200          *
4201          * - SkinTemplate:
4202          *    - Label the create action as "Edit", if the page can be an override.
4203          *
4204          * @return string|bool
4205          */
4206         public function getDefaultMessageText() {
4207                 if ( $this->mNamespace != NS_MEDIAWIKI ) { // Just in case
4208                         return false;
4209                 }
4210
4211                 list( $name, $lang ) = MessageCache::singleton()->figureMessage(
4212                         MediaWikiServices::getInstance()->getContentLanguage()->lcfirst( $this->getText() )
4213                 );
4214                 $message = wfMessage( $name )->inLanguage( $lang )->useDatabase( false );
4215
4216                 if ( $message->exists() ) {
4217                         return $message->plain();
4218                 } else {
4219                         return false;
4220                 }
4221         }
4222
4223         /**
4224          * Updates page_touched for this page; called from LinksUpdate.php
4225          *
4226          * @param string|null $purgeTime [optional] TS_MW timestamp
4227          * @return bool True if the update succeeded
4228          */
4229         public function invalidateCache( $purgeTime = null ) {
4230                 if ( wfReadOnly() ) {
4231                         return false;
4232                 } elseif ( $this->mArticleID === 0 ) {
4233                         return true; // avoid gap locking if we know it's not there
4234                 }
4235
4236                 $dbw = wfGetDB( DB_MASTER );
4237                 $dbw->onTransactionPreCommitOrIdle(
4238                         function () use ( $dbw ) {
4239                                 ResourceLoaderWikiModule::invalidateModuleCache(
4240                                         $this, null, null, $dbw->getDomainID() );
4241                         },
4242                         __METHOD__
4243                 );
4244
4245                 $conds = $this->pageCond();
4246                 DeferredUpdates::addUpdate(
4247                         new AutoCommitUpdate(
4248                                 $dbw,
4249                                 __METHOD__,
4250                                 function ( IDatabase $dbw, $fname ) use ( $conds, $purgeTime ) {
4251                                         $dbTimestamp = $dbw->timestamp( $purgeTime ?: time() );
4252                                         $dbw->update(
4253                                                 'page',
4254                                                 [ 'page_touched' => $dbTimestamp ],
4255                                                 $conds + [ 'page_touched < ' . $dbw->addQuotes( $dbTimestamp ) ],
4256                                                 $fname
4257                                         );
4258                                         MediaWikiServices::getInstance()->getLinkCache()->invalidateTitle( $this );
4259                                 }
4260                         ),
4261                         DeferredUpdates::PRESEND
4262                 );
4263
4264                 return true;
4265         }
4266
4267         /**
4268          * Update page_touched timestamps and send CDN purge messages for
4269          * pages linking to this title. May be sent to the job queue depending
4270          * on the number of links. Typically called on create and delete.
4271          */
4272         public function touchLinks() {
4273                 DeferredUpdates::addUpdate( new HTMLCacheUpdate( $this, 'pagelinks', 'page-touch' ) );
4274                 if ( $this->mNamespace == NS_CATEGORY ) {
4275                         DeferredUpdates::addUpdate(
4276                                 new HTMLCacheUpdate( $this, 'categorylinks', 'category-touch' )
4277                         );
4278                 }
4279         }
4280
4281         /**
4282          * Get the last touched timestamp
4283          *
4284          * @param IDatabase|null $db
4285          * @return string|false Last-touched timestamp
4286          */
4287         public function getTouched( $db = null ) {
4288                 if ( $db === null ) {
4289                         $db = wfGetDB( DB_REPLICA );
4290                 }
4291                 $touched = $db->selectField( 'page', 'page_touched', $this->pageCond(), __METHOD__ );
4292                 return $touched;
4293         }
4294
4295         /**
4296          * Get the timestamp when this page was updated since the user last saw it.
4297          *
4298          * @param User|null $user
4299          * @return string|bool|null String timestamp, false if not watched, null if nothing is unseen
4300          */
4301         public function getNotificationTimestamp( $user = null ) {
4302                 global $wgUser;
4303
4304                 // Assume current user if none given
4305                 if ( !$user ) {
4306                         $user = $wgUser;
4307                 }
4308                 // Check cache first
4309                 $uid = $user->getId();
4310                 if ( !$uid ) {
4311                         return false;
4312                 }
4313                 // avoid isset here, as it'll return false for null entries
4314                 if ( array_key_exists( $uid, $this->mNotificationTimestamp ) ) {
4315                         return $this->mNotificationTimestamp[$uid];
4316                 }
4317                 // Don't cache too much!
4318                 if ( count( $this->mNotificationTimestamp ) >= self::CACHE_MAX ) {
4319                         $this->mNotificationTimestamp = [];
4320                 }
4321
4322                 $store = MediaWikiServices::getInstance()->getWatchedItemStore();
4323                 $watchedItem = $store->getWatchedItem( $user, $this );
4324                 if ( $watchedItem ) {
4325                         $this->mNotificationTimestamp[$uid] = $watchedItem->getNotificationTimestamp();
4326                 } else {
4327                         $this->mNotificationTimestamp[$uid] = false;
4328                 }
4329
4330                 return $this->mNotificationTimestamp[$uid];
4331         }
4332
4333         /**
4334          * Generate strings used for xml 'id' names in monobook tabs
4335          *
4336          * @param string $prepend Defaults to 'nstab-'
4337          * @return string XML 'id' name
4338          */
4339         public function getNamespaceKey( $prepend = 'nstab-' ) {
4340                 // Gets the subject namespace of this title
4341                 $nsInfo = MediaWikiServices::getInstance()->getNamespaceInfo();
4342                 $subjectNS = $nsInfo->getSubject( $this->mNamespace );
4343                 // Prefer canonical namespace name for HTML IDs
4344                 $namespaceKey = $nsInfo->getCanonicalName( $subjectNS );
4345                 if ( $namespaceKey === false ) {
4346                         // Fallback to localised text
4347                         $namespaceKey = $this->getSubjectNsText();
4348                 }
4349                 // Makes namespace key lowercase
4350                 $namespaceKey = MediaWikiServices::getInstance()->getContentLanguage()->lc( $namespaceKey );
4351                 // Uses main
4352                 if ( $namespaceKey == '' ) {
4353                         $namespaceKey = 'main';
4354                 }
4355                 // Changes file to image for backwards compatibility
4356                 if ( $namespaceKey == 'file' ) {
4357                         $namespaceKey = 'image';
4358                 }
4359                 return $prepend . $namespaceKey;
4360         }
4361
4362         /**
4363          * Get all extant redirects to this Title
4364          *
4365          * @param int|null $ns Single namespace to consider; null to consider all namespaces
4366          * @return Title[] Array of Title redirects to this title
4367          */
4368         public function getRedirectsHere( $ns = null ) {
4369                 $redirs = [];
4370
4371                 $dbr = wfGetDB( DB_REPLICA );
4372                 $where = [
4373                         'rd_namespace' => $this->mNamespace,
4374                         'rd_title' => $this->mDbkeyform,
4375                         'rd_from = page_id'
4376                 ];
4377                 if ( $this->isExternal() ) {
4378                         $where['rd_interwiki'] = $this->mInterwiki;
4379                 } else {
4380                         $where[] = 'rd_interwiki = ' . $dbr->addQuotes( '' ) . ' OR rd_interwiki IS NULL';
4381                 }
4382                 if ( !is_null( $ns ) ) {
4383                         $where['page_namespace'] = $ns;
4384                 }
4385
4386                 $res = $dbr->select(
4387                         [ 'redirect', 'page' ],
4388                         [ 'page_namespace', 'page_title' ],
4389                         $where,
4390                         __METHOD__
4391                 );
4392
4393                 foreach ( $res as $row ) {
4394                         $redirs[] = self::newFromRow( $row );
4395                 }
4396                 return $redirs;
4397         }
4398
4399         /**
4400          * Check if this Title is a valid redirect target
4401          *
4402          * @return bool
4403          */
4404         public function isValidRedirectTarget() {
4405                 global $wgInvalidRedirectTargets;
4406
4407                 if ( $this->isSpecialPage() ) {
4408                         // invalid redirect targets are stored in a global array, but explicitly disallow Userlogout here
4409                         if ( $this->isSpecial( 'Userlogout' ) ) {
4410                                 return false;
4411                         }
4412
4413                         foreach ( $wgInvalidRedirectTargets as $target ) {
4414                                 if ( $this->isSpecial( $target ) ) {
4415                                         return false;
4416                                 }
4417                         }
4418                 }
4419
4420                 return true;
4421         }
4422
4423         /**
4424          * Get a backlink cache object
4425          *
4426          * @return BacklinkCache
4427          */
4428         public function getBacklinkCache() {
4429                 return BacklinkCache::get( $this );
4430         }
4431
4432         /**
4433          * Whether the magic words __INDEX__ and __NOINDEX__ function for this page.
4434          *
4435          * @return bool
4436          */
4437         public function canUseNoindex() {
4438                 global $wgExemptFromUserRobotsControl;
4439
4440                 $bannedNamespaces = $wgExemptFromUserRobotsControl ??
4441                         MediaWikiServices::getInstance()->getNamespaceInfo()->getContentNamespaces();
4442
4443                 return !in_array( $this->mNamespace, $bannedNamespaces );
4444         }
4445
4446         /**
4447          * Returns the raw sort key to be used for categories, with the specified
4448          * prefix.  This will be fed to Collation::getSortKey() to get a
4449          * binary sortkey that can be used for actual sorting.
4450          *
4451          * @param string $prefix The prefix to be used, specified using
4452          *   {{defaultsort:}} or like [[Category:Foo|prefix]].  Empty for no
4453          *   prefix.
4454          * @return string
4455          */
4456         public function getCategorySortkey( $prefix = '' ) {
4457                 $unprefixed = $this->getText();
4458
4459                 // Anything that uses this hook should only depend
4460                 // on the Title object passed in, and should probably
4461                 // tell the users to run updateCollations.php --force
4462                 // in order to re-sort existing category relations.
4463                 Hooks::run( 'GetDefaultSortkey', [ $this, &$unprefixed ] );
4464                 if ( $prefix !== '' ) {
4465                         # Separate with a line feed, so the unprefixed part is only used as
4466                         # a tiebreaker when two pages have the exact same prefix.
4467                         # In UCA, tab is the only character that can sort above LF
4468                         # so we strip both of them from the original prefix.
4469                         $prefix = strtr( $prefix, "\n\t", '  ' );
4470                         return "$prefix\n$unprefixed";
4471                 }
4472                 return $unprefixed;
4473         }
4474
4475         /**
4476          * Returns the page language code saved in the database, if $wgPageLanguageUseDB is set
4477          * to true in LocalSettings.php, otherwise returns false. If there is no language saved in
4478          * the db, it will return NULL.
4479          *
4480          * @return string|null|bool
4481          */
4482         private function getDbPageLanguageCode() {
4483                 global $wgPageLanguageUseDB;
4484
4485                 // check, if the page language could be saved in the database, and if so and
4486                 // the value is not requested already, lookup the page language using LinkCache
4487                 if ( $wgPageLanguageUseDB && $this->mDbPageLanguage === false ) {
4488                         $linkCache = MediaWikiServices::getInstance()->getLinkCache();
4489                         $linkCache->addLinkObj( $this );
4490                         $this->mDbPageLanguage = $linkCache->getGoodLinkFieldObj( $this, 'lang' );
4491                 }
4492
4493                 return $this->mDbPageLanguage;
4494         }
4495
4496         /**
4497          * Get the language in which the content of this page is written in
4498          * wikitext. Defaults to content language, but in certain cases it can be
4499          * e.g. $wgLang (such as special pages, which are in the user language).
4500          *
4501          * @since 1.18
4502          * @return Language
4503          */
4504         public function getPageLanguage() {
4505                 global $wgLang, $wgLanguageCode;
4506                 if ( $this->isSpecialPage() ) {
4507                         // special pages are in the user language
4508                         return $wgLang;
4509                 }
4510
4511                 // Checking if DB language is set
4512                 $dbPageLanguage = $this->getDbPageLanguageCode();
4513                 if ( $dbPageLanguage ) {
4514                         return wfGetLangObj( $dbPageLanguage );
4515                 }
4516
4517                 if ( !$this->mPageLanguage || $this->mPageLanguage[1] !== $wgLanguageCode ) {
4518                         // Note that this may depend on user settings, so the cache should
4519                         // be only per-request.
4520                         // NOTE: ContentHandler::getPageLanguage() may need to load the
4521                         // content to determine the page language!
4522                         // Checking $wgLanguageCode hasn't changed for the benefit of unit
4523                         // tests.
4524                         $contentHandler = ContentHandler::getForTitle( $this );
4525                         $langObj = $contentHandler->getPageLanguage( $this );
4526                         $this->mPageLanguage = [ $langObj->getCode(), $wgLanguageCode ];
4527                 } else {
4528                         $langObj = Language::factory( $this->mPageLanguage[0] );
4529                 }
4530
4531                 return $langObj;
4532         }
4533
4534         /**
4535          * Get the language in which the content of this page is written when
4536          * viewed by user. Defaults to content language, but in certain cases it can be
4537          * e.g. $wgLang (such as special pages, which are in the user language).
4538          *
4539          * @since 1.20
4540          * @return Language
4541          */
4542         public function getPageViewLanguage() {
4543                 global $wgLang;
4544
4545                 if ( $this->isSpecialPage() ) {
4546                         // If the user chooses a variant, the content is actually
4547                         // in a language whose code is the variant code.
4548                         $variant = $wgLang->getPreferredVariant();
4549                         if ( $wgLang->getCode() !== $variant ) {
4550                                 return Language::factory( $variant );
4551                         }
4552
4553                         return $wgLang;
4554                 }
4555
4556                 // Checking if DB language is set
4557                 $dbPageLanguage = $this->getDbPageLanguageCode();
4558                 if ( $dbPageLanguage ) {
4559                         $pageLang = wfGetLangObj( $dbPageLanguage );
4560                         $variant = $pageLang->getPreferredVariant();
4561                         if ( $pageLang->getCode() !== $variant ) {
4562                                 $pageLang = Language::factory( $variant );
4563                         }
4564
4565                         return $pageLang;
4566                 }
4567
4568                 // @note Can't be cached persistently, depends on user settings.
4569                 // @note ContentHandler::getPageViewLanguage() may need to load the
4570                 //   content to determine the page language!
4571                 $contentHandler = ContentHandler::getForTitle( $this );
4572                 $pageLang = $contentHandler->getPageViewLanguage( $this );
4573                 return $pageLang;
4574         }
4575
4576         /**
4577          * Get a list of rendered edit notices for this page.
4578          *
4579          * Array is keyed by the original message key, and values are rendered using parseAsBlock, so
4580          * they will already be wrapped in paragraphs.
4581          *
4582          * @since 1.21
4583          * @param int $oldid Revision ID that's being edited
4584          * @return array
4585          */
4586         public function getEditNotices( $oldid = 0 ) {
4587                 $notices = [];
4588
4589                 // Optional notice for the entire namespace
4590                 $editnotice_ns = 'editnotice-' . $this->mNamespace;
4591                 $msg = wfMessage( $editnotice_ns );
4592                 if ( $msg->exists() ) {
4593                         $html = $msg->parseAsBlock();
4594                         // Edit notices may have complex logic, but output nothing (T91715)
4595                         if ( trim( $html ) !== '' ) {
4596                                 $notices[$editnotice_ns] = Html::rawElement(
4597                                         'div',
4598                                         [ 'class' => [
4599                                                 'mw-editnotice',
4600                                                 'mw-editnotice-namespace',
4601                                                 Sanitizer::escapeClass( "mw-$editnotice_ns" )
4602                                         ] ],
4603                                         $html
4604                                 );
4605                         }
4606                 }
4607
4608                 if (
4609                         MediaWikiServices::getInstance()->getNamespaceInfo()->
4610                                 hasSubpages( $this->mNamespace )
4611                 ) {
4612                         // Optional notice for page itself and any parent page
4613                         $editnotice_base = $editnotice_ns;
4614                         foreach ( explode( '/', $this->mDbkeyform ) as $part ) {
4615                                 $editnotice_base .= '-' . $part;
4616                                 $msg = wfMessage( $editnotice_base );
4617                                 if ( $msg->exists() ) {
4618                                         $html = $msg->parseAsBlock();
4619                                         if ( trim( $html ) !== '' ) {
4620                                                 $notices[$editnotice_base] = Html::rawElement(
4621                                                         'div',
4622                                                         [ 'class' => [
4623                                                                 'mw-editnotice',
4624                                                                 'mw-editnotice-base',
4625                                                                 Sanitizer::escapeClass( "mw-$editnotice_base" )
4626                                                         ] ],
4627                                                         $html
4628                                                 );
4629                                         }
4630                                 }
4631                         }
4632                 } else {
4633                         // Even if there are no subpages in namespace, we still don't want "/" in MediaWiki message keys
4634                         $editnoticeText = $editnotice_ns . '-' . strtr( $this->mDbkeyform, '/', '-' );
4635                         $msg = wfMessage( $editnoticeText );
4636                         if ( $msg->exists() ) {
4637                                 $html = $msg->parseAsBlock();
4638                                 if ( trim( $html ) !== '' ) {
4639                                         $notices[$editnoticeText] = Html::rawElement(
4640                                                 'div',
4641                                                 [ 'class' => [
4642                                                         'mw-editnotice',
4643                                                         'mw-editnotice-page',
4644                                                         Sanitizer::escapeClass( "mw-$editnoticeText" )
4645                                                 ] ],
4646                                                 $html
4647                                         );
4648                                 }
4649                         }
4650                 }
4651
4652                 Hooks::run( 'TitleGetEditNotices', [ $this, $oldid, &$notices ] );
4653                 return $notices;
4654         }
4655
4656         /**
4657          * @param int $flags Bitfield of class READ_* constants
4658          * @return string|bool
4659          */
4660         private function loadFieldFromDB( $field, $flags ) {
4661                 if ( !in_array( $field, self::getSelectFields(), true ) ) {
4662                         return false; // field does not exist
4663                 }
4664
4665                 $flags |= ( $flags & self::GAID_FOR_UPDATE ) ? self::READ_LATEST : 0; // b/c
4666                 list( $index, $options ) = DBAccessObjectUtils::getDBOptions( $flags );
4667
4668                 return wfGetDB( $index )->selectField(
4669                         'page',
4670                         $field,
4671                         $this->pageCond(),
4672                         __METHOD__,
4673                         $options
4674                 );
4675         }
4676
4677         /**
4678          * @return array
4679          */
4680         public function __sleep() {
4681                 return [
4682                         'mNamespace',
4683                         'mDbkeyform',
4684                         'mFragment',
4685                         'mInterwiki',
4686                         'mLocalInterwiki',
4687                         'mUserCaseDBKey',
4688                         'mDefaultNamespace',
4689                 ];
4690         }
4691
4692         public function __wakeup() {
4693                 $this->mArticleID = ( $this->mNamespace >= 0 ) ? -1 : 0;
4694                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
4695                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
4696         }
4697
4698 }