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 Wikimedia\Rdbms\Database;
  26 use Wikimedia\Rdbms\IDatabase;
  27 use MediaWiki\Linker\LinkTarget;
  28 use MediaWiki\Interwiki\InterwikiLookup;
  29 use MediaWiki\MediaWikiServices;
  30
  31 /**
  32  * Represents a title within MediaWiki.
  33  * Optionally may contain an interwiki designation or namespace.
  34  * @note This class can fetch various kinds of data from the database;
  35  *       however, it does so inefficiently.
  36  * @note Consider using a TitleValue object instead. TitleValue is more lightweight
  37  *       and does not rely on global state or the database.
  38  */
  39 class Title implements LinkTarget {
  40         /** @var HashBagOStuff */
  41         static private $titleCache = null;
  42
  43         /**
  44          * Title::newFromText maintains a cache to avoid expensive re-normalization of
  45          * commonly used titles. On a batch operation this can become a memory leak
  46          * if not bounded. After hitting this many titles reset the cache.
  47          */
  48         const CACHE_MAX = 1000;
  49
  50         /**
  51          * Used to be GAID_FOR_UPDATE define. Used with getArticleID() and friends
  52          * to use the master DB
  53          */
  54         const GAID_FOR_UPDATE = 1;
  55
  56         /**
  57          * @name Private member variables
  58          * Please use the accessor functions instead.
  59          * @private
  60          */
  61         // @{
  62
  63         /** @var string Text form (spaces not underscores) of the main part */
  64         public $mTextform = '';
  65
  66         /** @var string URL-encoded form of the main part */
  67         public $mUrlform = '';
  68
  69         /** @var string Main part with underscores */
  70         public $mDbkeyform = '';
  71
  72         /** @var string Database key with the initial letter in the case specified by the user */
  73         protected $mUserCaseDBKey;
  74
  75         /** @var int Namespace index, i.e. one of the NS_xxxx constants */
  76         public $mNamespace = NS_MAIN;
  77
  78         /** @var string Interwiki prefix */
  79         public $mInterwiki = '';
  80
  81         /** @var bool Was this Title created from a string with a local interwiki prefix? */
  82         private $mLocalInterwiki = false;
  83
  84         /** @var string Title fragment (i.e. the bit after the #) */
  85         public $mFragment = '';
  86
  87         /** @var int Article ID, fetched from the link cache on demand */
  88         public $mArticleID = -1;
  89
  90         /** @var bool|int ID of most recent revision */
  91         protected $mLatestID = false;
  92
  93         /**
  94          * @var bool|string ID of the page's content model, i.e. one of the
  95          *   CONTENT_MODEL_XXX constants
  96          */
  97         private $mContentModel = false;
  98
  99         /**
 100          * @var bool If a content model was forced via setContentModel()
 101          *   this will be true to avoid having other code paths reset it
 102          */
 103         private $mForcedContentModel = false;
 104
 105         /** @var int Estimated number of revisions; null of not loaded */
 106         private $mEstimateRevisions;
 107
 108         /** @var array Array of groups allowed to edit this article */
 109         public $mRestrictions = [];
 110
 111         /** @var string|bool */
 112         protected $mOldRestrictions = false;
 113
 114         /** @var bool Cascade restrictions on this page to included templates and images? */
 115         public $mCascadeRestriction;
 116
 117         /** Caching the results of getCascadeProtectionSources */
 118         public $mCascadingRestrictions;
 119
 120         /** @var array When do the restrictions on this page expire? */
 121         protected $mRestrictionsExpiry = [];
 122
 123         /** @var bool Are cascading restrictions in effect on this page? */
 124         protected $mHasCascadingRestrictions;
 125
 126         /** @var array Where are the cascading restrictions coming from on this page? */
 127         public $mCascadeSources;
 128
 129         /** @var bool Boolean for initialisation on demand */
 130         public $mRestrictionsLoaded = false;
 131
 132         /** @var string Text form including namespace/interwiki, initialised on demand */
 133         protected $mPrefixedText = null;
 134
 135         /** @var mixed Cached value for getTitleProtection (create protection) */
 136         public $mTitleProtection;
 137
 138         /**
 139          * @var int Namespace index when there is no namespace. Don't change the
 140          *   following default, NS_MAIN is hardcoded in several places. See T2696.
 141          *   Zero except in {{transclusion}} tags.
 142          */
 143         public $mDefaultNamespace = NS_MAIN;
 144
 145         /** @var int The page length, 0 for special pages */
 146         protected $mLength = -1;
 147
 148         /** @var null Is the article at this title a redirect? */
 149         public $mRedirect = null;
 150
 151         /** @var array Associative array of user ID -> timestamp/false */
 152         private $mNotificationTimestamp = [];
 153
 154         /** @var bool Whether a page has any subpages */
 155         private $mHasSubpages;
 156
 157         /** @var bool The (string) language code of the page's language and content code. */
 158         private $mPageLanguage = false;
 159
 160         /** @var string|bool|null The page language code from the database, null if not saved in
 161          * the database or false if not loaded, yet. */
 162         private $mDbPageLanguage = false;
 163
 164         /** @var TitleValue A corresponding TitleValue object */
 165         private $mTitleValue = null;
 166
 167         /** @var bool Would deleting this page be a big deletion? */
 168         private $mIsBigDeletion = null;
 169         // @}
 170
 171         /**
 172          * B/C kludge: provide a TitleParser for use by Title.
 173          * Ideally, Title would have no methods that need this.
 174          * Avoid usage of this singleton by using TitleValue
 175          * and the associated services when possible.
 176          *
 177          * @return TitleFormatter
 178          */
 179         private static function getTitleFormatter() {
 180                 return MediaWikiServices::getInstance()->getTitleFormatter();
 181         }
 182
 183         /**
 184          * B/C kludge: provide an InterwikiLookup for use by Title.
 185          * Ideally, Title would have no methods that need this.
 186          * Avoid usage of this singleton by using TitleValue
 187          * and the associated services when possible.
 188          *
 189          * @return InterwikiLookup
 190          */
 191         private static function getInterwikiLookup() {
 192                 return MediaWikiServices::getInstance()->getInterwikiLookup();
 193         }
 194
 195         /**
 196          * @access protected
 197          */
 198         function __construct() {
 199         }
 200
 201         /**
 202          * Create a new Title from a prefixed DB key
 203          *
 204          * @param string $key The database key, which has underscores
 205          *      instead of spaces, possibly including namespace and
 206          *      interwiki prefixes
 207          * @return Title|null Title, or null on an error
 208          */
 209         public static function newFromDBkey( $key ) {
 210                 $t = new Title();
 211                 $t->mDbkeyform = $key;
 212
 213                 try {
 214                         $t->secureAndSplit();
 215                         return $t;
 216                 } catch ( MalformedTitleException $ex ) {
 217                         return null;
 218                 }
 219         }
 220
 221         /**
 222          * Create a new Title from a TitleValue
 223          *
 224          * @param TitleValue $titleValue Assumed to be safe.
 225          *
 226          * @return Title
 227          */
 228         public static function newFromTitleValue( TitleValue $titleValue ) {
 229                 return self::newFromLinkTarget( $titleValue );
 230         }
 231
 232         /**
 233          * Create a new Title from a LinkTarget
 234          *
 235          * @param LinkTarget $linkTarget Assumed to be safe.
 236          *
 237          * @return Title
 238          */
 239         public static function newFromLinkTarget( LinkTarget $linkTarget ) {
 240                 if ( $linkTarget instanceof Title ) {
 241                         // Special case if it's already a Title object
 242                         return $linkTarget;
 243                 }
 244                 return self::makeTitle(
 245                         $linkTarget->getNamespace(),
 246                         $linkTarget->getText(),
 247                         $linkTarget->getFragment(),
 248                         $linkTarget->getInterwiki()
 249                 );
 250         }
 251
 252         /**
 253          * Create a new Title from text, such as what one would find in a link. De-
 254          * codes any HTML entities in the text.
 255          *
 256          * Title objects returned by this method are guaranteed to be valid, and
 257          * thus return true from the isValid() method.
 258          *
 259          * @param string|int|null $text The link text; spaces, prefixes, and an
 260          *   initial ':' indicating the main namespace are accepted.
 261          * @param int $defaultNamespace The namespace to use if none is specified
 262          *   by a prefix.  If you want to force a specific namespace even if
 263          *   $text might begin with a namespace prefix, use makeTitle() or
 264          *   makeTitleSafe().
 265          * @throws InvalidArgumentException
 266          * @return Title|null Title or null on an error.
 267          */
 268         public static function newFromText( $text, $defaultNamespace = NS_MAIN ) {
 269                 // DWIM: Integers can be passed in here when page titles are used as array keys.
 270                 if ( $text !== null && !is_string( $text ) && !is_int( $text ) ) {
 271                         throw new InvalidArgumentException( '$text must be a string.' );
 272                 }
 273                 if ( $text === null ) {
 274                         return null;
 275                 }
 276
 277                 try {
 278                         return self::newFromTextThrow( strval( $text ), $defaultNamespace );
 279                 } catch ( MalformedTitleException $ex ) {
 280                         return null;
 281                 }
 282         }
 283
 284         /**
 285          * Like Title::newFromText(), but throws MalformedTitleException when the title is invalid,
 286          * rather than returning null.
 287          *
 288          * The exception subclasses encode detailed information about why the title is invalid.
 289          *
 290          * Title objects returned by this method are guaranteed to be valid, and
 291          * thus return true from the isValid() method.
 292          *
 293          * @see Title::newFromText
 294          *
 295          * @since 1.25
 296          * @param string $text Title text to check
 297          * @param int $defaultNamespace
 298          * @throws MalformedTitleException If the title is invalid
 299          * @return Title
 300          */
 301         public static function newFromTextThrow( $text, $defaultNamespace = NS_MAIN ) {
 302                 if ( is_object( $text ) ) {
 303                         throw new MWException( '$text must be a string, given an object' );
 304                 }
 305
 306                 $titleCache = self::getTitleCache();
 307
 308                 // Wiki pages often contain multiple links to the same page.
 309                 // Title normalization and parsing can become expensive on pages with many
 310                 // links, so we can save a little time by caching them.
 311                 // In theory these are value objects and won't get changed...
 312                 if ( $defaultNamespace == NS_MAIN ) {
 313                         $t = $titleCache->get( $text );
 314                         if ( $t ) {
 315                                 return $t;
 316                         }
 317                 }
 318
 319                 // Convert things like &eacute; &#257; or &#x3017; into normalized (T16952) text
 320                 $filteredText = Sanitizer::decodeCharReferencesAndNormalize( $text );
 321
 322                 $t = new Title();
 323                 $t->mDbkeyform = strtr( $filteredText, ' ', '_' );
 324                 $t->mDefaultNamespace = intval( $defaultNamespace );
 325
 326                 $t->secureAndSplit();
 327                 if ( $defaultNamespace == NS_MAIN ) {
 328                         $titleCache->set( $text, $t );
 329                 }
 330                 return $t;
 331         }
 332
 333         /**
 334          * THIS IS NOT THE FUNCTION YOU WANT. Use Title::newFromText().
 335          *
 336          * Example of wrong and broken code:
 337          * $title = Title::newFromURL( $wgRequest->getVal( 'title' ) );
 338          *
 339          * Example of right code:
 340          * $title = Title::newFromText( $wgRequest->getVal( 'title' ) );
 341          *
 342          * Create a new Title from URL-encoded text. Ensures that
 343          * the given title's length does not exceed the maximum.
 344          *
 345          * @param string $url The title, as might be taken from a URL
 346          * @return Title|null The new object, or null on an error
 347          */
 348         public static function newFromURL( $url ) {
 349                 $t = new Title();
 350
 351                 # For compatibility with old buggy URLs. "+" is usually not valid in titles,
 352                 # but some URLs used it as a space replacement and they still come
 353                 # from some external search tools.
 354                 if ( strpos( self::legalChars(), '+' ) === false ) {
 355                         $url = strtr( $url, '+', ' ' );
 356                 }
 357
 358                 $t->mDbkeyform = strtr( $url, ' ', '_' );
 359
 360                 try {
 361                         $t->secureAndSplit();
 362                         return $t;
 363                 } catch ( MalformedTitleException $ex ) {
 364                         return null;
 365                 }
 366         }
 367
 368         /**
 369          * @return HashBagOStuff
 370          */
 371         private static function getTitleCache() {
 372                 if ( self::$titleCache == null ) {
 373                         self::$titleCache = new HashBagOStuff( [ 'maxKeys' => self::CACHE_MAX ] );
 374                 }
 375                 return self::$titleCache;
 376         }
 377
 378         /**
 379          * Returns a list of fields that are to be selected for initializing Title
 380          * objects or LinkCache entries. Uses $wgContentHandlerUseDB to determine
 381          * whether to include page_content_model.
 382          *
 383          * @return array
 384          */
 385         protected static function getSelectFields() {
 386                 global $wgContentHandlerUseDB, $wgPageLanguageUseDB;
 387
 388                 $fields = [
 389                         'page_namespace', 'page_title', 'page_id',
 390                         'page_len', 'page_is_redirect', 'page_latest',
 391                 ];
 392
 393                 if ( $wgContentHandlerUseDB ) {
 394                         $fields[] = 'page_content_model';
 395                 }
 396
 397                 if ( $wgPageLanguageUseDB ) {
 398                         $fields[] = 'page_lang';
 399                 }
 400
 401                 return $fields;
 402         }
 403
 404         /**
 405          * Create a new Title from an article ID
 406          *
 407          * @param int $id The page_id corresponding to the Title to create
 408          * @param int $flags Use Title::GAID_FOR_UPDATE to use master
 409          * @return Title|null The new object, or null on an error
 410          */
 411         public static function newFromID( $id, $flags = 0 ) {
 412                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_REPLICA );
 413                 $row = $db->selectRow(
 414                         'page',
 415                         self::getSelectFields(),
 416                         [ 'page_id' => $id ],
 417                         __METHOD__
 418                 );
 419                 if ( $row !== false ) {
 420                         $title = self::newFromRow( $row );
 421                 } else {
 422                         $title = null;
 423                 }
 424                 return $title;
 425         }
 426
 427         /**
 428          * Make an array of titles from an array of IDs
 429          *
 430          * @param int[] $ids Array of IDs
 431          * @return Title[] Array of Titles
 432          */
 433         public static function newFromIDs( $ids ) {
 434                 if ( !count( $ids ) ) {
 435                         return [];
 436                 }
 437                 $dbr = wfGetDB( DB_REPLICA );
 438
 439                 $res = $dbr->select(
 440                         'page',
 441                         self::getSelectFields(),
 442                         [ 'page_id' => $ids ],
 443                         __METHOD__
 444                 );
 445
 446                 $titles = [];
 447                 foreach ( $res as $row ) {
 448                         $titles[] = self::newFromRow( $row );
 449                 }
 450                 return $titles;
 451         }
 452
 453         /**
 454          * Make a Title object from a DB row
 455          *
 456          * @param stdClass $row Object database row (needs at least page_title,page_namespace)
 457          * @return Title Corresponding Title
 458          */
 459         public static function newFromRow( $row ) {
 460                 $t = self::makeTitle( $row->page_namespace, $row->page_title );
 461                 $t->loadFromRow( $row );
 462                 return $t;
 463         }
 464
 465         /**
 466          * Load Title object fields from a DB row.
 467          * If false is given, the title will be treated as non-existing.
 468          *
 469          * @param stdClass|bool $row Database row
 470          */
 471         public function loadFromRow( $row ) {
 472                 if ( $row ) { // page found
 473                         if ( isset( $row->page_id ) ) {
 474                                 $this->mArticleID = (int)$row->page_id;
 475                         }
 476                         if ( isset( $row->page_len ) ) {
 477                                 $this->mLength = (int)$row->page_len;
 478                         }
 479                         if ( isset( $row->page_is_redirect ) ) {
 480                                 $this->mRedirect = (bool)$row->page_is_redirect;
 481                         }
 482                         if ( isset( $row->page_latest ) ) {
 483                                 $this->mLatestID = (int)$row->page_latest;
 484                         }
 485                         if ( !$this->mForcedContentModel && isset( $row->page_content_model ) ) {
 486                                 $this->mContentModel = strval( $row->page_content_model );
 487                         } elseif ( !$this->mForcedContentModel ) {
 488                                 $this->mContentModel = false; # initialized lazily in getContentModel()
 489                         }
 490                         if ( isset( $row->page_lang ) ) {
 491                                 $this->mDbPageLanguage = (string)$row->page_lang;
 492                         }
 493                         if ( isset( $row->page_restrictions ) ) {
 494                                 $this->mOldRestrictions = $row->page_restrictions;
 495                         }
 496                 } else { // page not found
 497                         $this->mArticleID = 0;
 498                         $this->mLength = 0;
 499                         $this->mRedirect = false;
 500                         $this->mLatestID = 0;
 501                         if ( !$this->mForcedContentModel ) {
 502                                 $this->mContentModel = false; # initialized lazily in getContentModel()
 503                         }
 504                 }
 505         }
 506
 507         /**
 508          * Create a new Title from a namespace index and a DB key.
 509          *
 510          * It's assumed that $ns and $title are safe, for instance when
 511          * they came directly from the database or a special page name,
 512          * not from user input.
 513          *
 514          * No validation is applied. For convenience, spaces are normalized
 515          * to underscores, so that e.g. user_text fields can be used directly.
 516          *
 517          * @note This method may return Title objects that are "invalid"
 518          * according to the isValid() method. This is usually caused by
 519          * configuration changes: e.g. a namespace that was once defined is
 520          * no longer configured, or a character that was once allowed in
 521          * titles is now forbidden.
 522          *
 523          * @param int $ns The namespace of the article
 524          * @param string $title The unprefixed database key form
 525          * @param string $fragment The link fragment (after the "#")
 526          * @param string $interwiki The interwiki prefix
 527          * @return Title The new object
 528          */
 529         public static function makeTitle( $ns, $title, $fragment = '', $interwiki = '' ) {
 530                 $t = new Title();
 531                 $t->mInterwiki = $interwiki;
 532                 $t->mFragment = $fragment;
 533                 $t->mNamespace = $ns = intval( $ns );
 534                 $t->mDbkeyform = strtr( $title, ' ', '_' );
 535                 $t->mArticleID = ( $ns >= 0 ) ? -1 : 0;
 536                 $t->mUrlform = wfUrlencode( $t->mDbkeyform );
 537                 $t->mTextform = strtr( $title, '_', ' ' );
 538                 $t->mContentModel = false; # initialized lazily in getContentModel()
 539                 return $t;
 540         }
 541
 542         /**
 543          * Create a new Title from a namespace index and a DB key.
 544          * The parameters will be checked for validity, which is a bit slower
 545          * than makeTitle() but safer for user-provided data.
 546          *
 547          * Title objects returned by makeTitleSafe() are guaranteed to be valid,
 548          * that is, they return true from the isValid() method. If no valid Title
 549          * can be constructed from the input, this method returns null.
 550          *
 551          * @param int $ns The namespace of the article
 552          * @param string $title Database key form
 553          * @param string $fragment The link fragment (after the "#")
 554          * @param string $interwiki Interwiki prefix
 555          * @return Title|null The new object, or null on an error
 556          */
 557         public static function makeTitleSafe( $ns, $title, $fragment = '', $interwiki = '' ) {
 558                 // NOTE: ideally, this would just call makeTitle() and then isValid(),
 559                 // but presently, that means more overhead on a potential performance hotspot.
 560
 561                 if ( !MWNamespace::exists( $ns ) ) {
 562                         return null;
 563                 }
 564
 565                 $t = new Title();
 566                 $t->mDbkeyform = self::makeName( $ns, $title, $fragment, $interwiki, true );
 567
 568                 try {
 569                         $t->secureAndSplit();
 570                         return $t;
 571                 } catch ( MalformedTitleException $ex ) {
 572                         return null;
 573                 }
 574         }
 575
 576         /**
 577          * Create a new Title for the Main Page
 578          *
 579          * @return Title The new object
 580          */
 581         public static function newMainPage() {
 582                 $title = self::newFromText( wfMessage( 'mainpage' )->inContentLanguage()->text() );
 583                 // Don't give fatal errors if the message is broken
 584                 if ( !$title ) {
 585                         $title = self::newFromText( 'Main Page' );
 586                 }
 587                 return $title;
 588         }
 589
 590         /**
 591          * Get the prefixed DB key associated with an ID
 592          *
 593          * @param int $id The page_id of the article
 594          * @return Title|null An object representing the article, or null if no such article was found
 595          */
 596         public static function nameOf( $id ) {
 597                 $dbr = wfGetDB( DB_REPLICA );
 598
 599                 $s = $dbr->selectRow(
 600                         'page',
 601                         [ 'page_namespace', 'page_title' ],
 602                         [ 'page_id' => $id ],
 603                         __METHOD__
 604                 );
 605                 if ( $s === false ) {
 606                         return null;
 607                 }
 608
 609                 $n = self::makeName( $s->page_namespace, $s->page_title );
 610                 return $n;
 611         }
 612
 613         /**
 614          * Get a regex character class describing the legal characters in a link
 615          *
 616          * @return string The list of characters, not delimited
 617          */
 618         public static function legalChars() {
 619                 global $wgLegalTitleChars;
 620                 return $wgLegalTitleChars;
 621         }
 622
 623         /**
 624          * Returns a simple regex that will match on characters and sequences invalid in titles.
 625          * Note that this doesn't pick up many things that could be wrong with titles, but that
 626          * replacing this regex with something valid will make many titles valid.
 627          *
 628          * @deprecated since 1.25, use MediaWikiTitleCodec::getTitleInvalidRegex() instead
 629          *
 630          * @return string Regex string
 631          */
 632         static function getTitleInvalidRegex() {
 633                 wfDeprecated( __METHOD__, '1.25' );
 634                 return MediaWikiTitleCodec::getTitleInvalidRegex();
 635         }
 636
 637         /**
 638          * Utility method for converting a character sequence from bytes to Unicode.
 639          *
 640          * Primary usecase being converting $wgLegalTitleChars to a sequence usable in
 641          * javascript, as PHP uses UTF-8 bytes where javascript uses Unicode code units.
 642          *
 643          * @param string $byteClass
 644          * @return string
 645          */
 646         public static function convertByteClassToUnicodeClass( $byteClass ) {
 647                 $length = strlen( $byteClass );
 648                 // Input token queue
 649                 $x0 = $x1 = $x2 = '';
 650                 // Decoded queue
 651                 $d0 = $d1 = $d2 = '';
 652                 // Decoded integer codepoints
 653                 $ord0 = $ord1 = $ord2 = 0;
 654                 // Re-encoded queue
 655                 $r0 = $r1 = $r2 = '';
 656                 // Output
 657                 $out = '';
 658                 // Flags
 659                 $allowUnicode = false;
 660                 for ( $pos = 0; $pos < $length; $pos++ ) {
 661                         // Shift the queues down
 662                         $x2 = $x1;
 663                         $x1 = $x0;
 664                         $d2 = $d1;
 665                         $d1 = $d0;
 666                         $ord2 = $ord1;
 667                         $ord1 = $ord0;
 668                         $r2 = $r1;
 669                         $r1 = $r0;
 670                         // Load the current input token and decoded values
 671                         $inChar = $byteClass[$pos];
 672                         if ( $inChar == '\\' ) {
 673                                 if ( preg_match( '/x([0-9a-fA-F]{2})/A', $byteClass, $m, 0, $pos + 1 ) ) {
 674                                         $x0 = $inChar . $m[0];
 675                                         $d0 = chr( hexdec( $m[1] ) );
 676                                         $pos += strlen( $m[0] );
 677                                 } elseif ( preg_match( '/[0-7]{3}/A', $byteClass, $m, 0, $pos + 1 ) ) {
 678                                         $x0 = $inChar . $m[0];
 679                                         $d0 = chr( octdec( $m[0] ) );
 680                                         $pos += strlen( $m[0] );
 681                                 } elseif ( $pos + 1 >= $length ) {
 682                                         $x0 = $d0 = '\\';
 683                                 } else {
 684                                         $d0 = $byteClass[$pos + 1];
 685                                         $x0 = $inChar . $d0;
 686                                         $pos += 1;
 687                                 }
 688                         } else {
 689                                 $x0 = $d0 = $inChar;
 690                         }
 691                         $ord0 = ord( $d0 );
 692                         // Load the current re-encoded value
 693                         if ( $ord0 < 32 || $ord0 == 0x7f ) {
 694                                 $r0 = sprintf( '\x%02x', $ord0 );
 695                         } elseif ( $ord0 >= 0x80 ) {
 696                                 // Allow unicode if a single high-bit character appears
 697                                 $r0 = sprintf( '\x%02x', $ord0 );
 698                                 $allowUnicode = true;
 699                         } elseif ( strpos( '-\\[]^', $d0 ) !== false ) {
 700                                 $r0 = '\\' . $d0;
 701                         } else {
 702                                 $r0 = $d0;
 703                         }
 704                         // Do the output
 705                         if ( $x0 !== '' && $x1 === '-' && $x2 !== '' ) {
 706                                 // Range
 707                                 if ( $ord2 > $ord0 ) {
 708                                         // Empty range
 709                                 } elseif ( $ord0 >= 0x80 ) {
 710                                         // Unicode range
 711                                         $allowUnicode = true;
 712                                         if ( $ord2 < 0x80 ) {
 713                                                 // Keep the non-unicode section of the range
 714                                                 $out .= "$r2-\\x7F";
 715                                         }
 716                                 } else {
 717                                         // Normal range
 718                                         $out .= "$r2-$r0";
 719                                 }
 720                                 // Reset state to the initial value
 721                                 $x0 = $x1 = $d0 = $d1 = $r0 = $r1 = '';
 722                         } elseif ( $ord2 < 0x80 ) {
 723                                 // ASCII character
 724                                 $out .= $r2;
 725                         }
 726                 }
 727                 if ( $ord1 < 0x80 ) {
 728                         $out .= $r1;
 729                 }
 730                 if ( $ord0 < 0x80 ) {
 731                         $out .= $r0;
 732                 }
 733                 if ( $allowUnicode ) {
 734                         $out .= '\u0080-\uFFFF';
 735                 }
 736                 return $out;
 737         }
 738
 739         /**
 740          * Make a prefixed DB key from a DB key and a namespace index
 741          *
 742          * @param int $ns Numerical representation of the namespace
 743          * @param string $title The DB key form the title
 744          * @param string $fragment The link fragment (after the "#")
 745          * @param string $interwiki The interwiki prefix
 746          * @param bool $canonicalNamespace If true, use the canonical name for
 747          *   $ns instead of the localized version.
 748          * @return string The prefixed form of the title
 749          */
 750         public static function makeName( $ns, $title, $fragment = '', $interwiki = '',
 751                 $canonicalNamespace = false
 752         ) {
 753                 global $wgContLang;
 754
 755                 if ( $canonicalNamespace ) {
 756                         $namespace = MWNamespace::getCanonicalName( $ns );
 757                 } else {
 758                         $namespace = $wgContLang->getNsText( $ns );
 759                 }
 760                 $name = $namespace == '' ? $title : "$namespace:$title";
 761                 if ( strval( $interwiki ) != '' ) {
 762                         $name = "$interwiki:$name";
 763                 }
 764                 if ( strval( $fragment ) != '' ) {
 765                         $name .= '#' . $fragment;
 766                 }
 767                 return $name;
 768         }
 769
 770         /**
 771          * Escape a text fragment, say from a link, for a URL
 772          *
 773          * @deprecated since 1.30, use Sanitizer::escapeIdForLink() or escapeIdForExternalInterwiki()
 774          *
 775          * @param string $fragment Containing a URL or link fragment (after the "#")
 776          * @return string Escaped string
 777          */
 778         static function escapeFragmentForURL( $fragment ) {
 779                 # Note that we don't urlencode the fragment.  urlencoded Unicode
 780                 # fragments appear not to work in IE (at least up to 7) or in at least
 781                 # one version of Opera 9.x.  The W3C validator, for one, doesn't seem
 782                 # to care if they aren't encoded.
 783                 return Sanitizer::escapeId( $fragment, 'noninitial' );
 784         }
 785
 786         /**
 787          * Callback for usort() to do title sorts by (namespace, title)
 788          *
 789          * @param LinkTarget $a
 790          * @param LinkTarget $b
 791          *
 792          * @return int Result of string comparison, or namespace comparison
 793          */
 794         public static function compare( LinkTarget $a, LinkTarget $b ) {
 795                 if ( $a->getNamespace() == $b->getNamespace() ) {
 796                         return strcmp( $a->getText(), $b->getText() );
 797                 } else {
 798                         return $a->getNamespace() - $b->getNamespace();
 799                 }
 800         }
 801
 802         /**
 803          * Returns true if the title is valid, false if it is invalid.
 804          *
 805          * Valid titles can be round-tripped via makeTitleSafe() and newFromText().
 806          * Invalid titles may get returned from makeTitle(), and it may be useful to
 807          * allow them to exist, e.g. in order to process log entries about pages in
 808          * namespaces that belong to extensions that are no longer installed.
 809          *
 810          * @note This method is relatively expensive. When constructing Title
 811          * objects that need to be valid, use an instantiator method that is guaranteed
 812          * to return valid titles, such as makeTitleSafe() or newFromText().
 813          *
 814          * @return bool
 815          */
 816         public function isValid() {
 817                 $ns = $this->getNamespace();
 818
 819                 if ( !MWNamespace::exists( $ns ) ) {
 820                         return false;
 821                 }
 822
 823                 try {
 824                         $parser = MediaWikiServices::getInstance()->getTitleParser();
 825                         $parser->parseTitle( $this->getDBkey(), $ns );
 826                         return true;
 827                 } catch ( MalformedTitleException $ex ) {
 828                         return false;
 829                 }
 830         }
 831
 832         /**
 833          * Determine whether the object refers to a page within
 834          * this project (either this wiki or a wiki with a local
 835          * interwiki, see https://www.mediawiki.org/wiki/Manual:Interwiki_table#iw_local )
 836          *
 837          * @return bool True if this is an in-project interwiki link or a wikilink, false otherwise
 838          */
 839         public function isLocal() {
 840                 if ( $this->isExternal() ) {
 841                         $iw = self::getInterwikiLookup()->fetch( $this->mInterwiki );
 842                         if ( $iw ) {
 843                                 return $iw->isLocal();
 844                         }
 845                 }
 846                 return true;
 847         }
 848
 849         /**
 850          * Is this Title interwiki?
 851          *
 852          * @return bool
 853          */
 854         public function isExternal() {
 855                 return $this->mInterwiki !== '';
 856         }
 857
 858         /**
 859          * Get the interwiki prefix
 860          *
 861          * Use Title::isExternal to check if a interwiki is set
 862          *
 863          * @return string Interwiki prefix
 864          */
 865         public function getInterwiki() {
 866                 return $this->mInterwiki;
 867         }
 868
 869         /**
 870          * Was this a local interwiki link?
 871          *
 872          * @return bool
 873          */
 874         public function wasLocalInterwiki() {
 875                 return $this->mLocalInterwiki;
 876         }
 877
 878         /**
 879          * Determine whether the object refers to a page within
 880          * this project and is transcludable.
 881          *
 882          * @return bool True if this is transcludable
 883          */
 884         public function isTrans() {
 885                 if ( !$this->isExternal() ) {
 886                         return false;
 887                 }
 888
 889                 return self::getInterwikiLookup()->fetch( $this->mInterwiki )->isTranscludable();
 890         }
 891
 892         /**
 893          * Returns the DB name of the distant wiki which owns the object.
 894          *
 895          * @return string|false The DB name
 896          */
 897         public function getTransWikiID() {
 898                 if ( !$this->isExternal() ) {
 899                         return false;
 900                 }
 901
 902                 return self::getInterwikiLookup()->fetch( $this->mInterwiki )->getWikiID();
 903         }
 904
 905         /**
 906          * Get a TitleValue object representing this Title.
 907          *
 908          * @note Not all valid Titles have a corresponding valid TitleValue
 909          * (e.g. TitleValues cannot represent page-local links that have a
 910          * fragment but no title text).
 911          *
 912          * @return TitleValue|null
 913          */
 914         public function getTitleValue() {
 915                 if ( $this->mTitleValue === null ) {
 916                         try {
 917                                 $this->mTitleValue = new TitleValue(
 918                                         $this->getNamespace(),
 919                                         $this->getDBkey(),
 920                                         $this->getFragment(),
 921                                         $this->getInterwiki()
 922                                 );
 923                         } catch ( InvalidArgumentException $ex ) {
 924                                 wfDebug( __METHOD__ . ': Can\'t create a TitleValue for [[' .
 925                                         $this->getPrefixedText() . ']]: ' . $ex->getMessage() . "\n" );
 926                         }
 927                 }
 928
 929                 return $this->mTitleValue;
 930         }
 931
 932         /**
 933          * Get the text form (spaces not underscores) of the main part
 934          *
 935          * @return string Main part of the title
 936          */
 937         public function getText() {
 938                 return $this->mTextform;
 939         }
 940
 941         /**
 942          * Get the URL-encoded form of the main part
 943          *
 944          * @return string Main part of the title, URL-encoded
 945          */
 946         public function getPartialURL() {
 947                 return $this->mUrlform;
 948         }
 949
 950         /**
 951          * Get the main part with underscores
 952          *
 953          * @return string Main part of the title, with underscores
 954          */
 955         public function getDBkey() {
 956                 return $this->mDbkeyform;
 957         }
 958
 959         /**
 960          * Get the DB key with the initial letter case as specified by the user
 961          *
 962          * @return string DB key
 963          */
 964         function getUserCaseDBKey() {
 965                 if ( !is_null( $this->mUserCaseDBKey ) ) {
 966                         return $this->mUserCaseDBKey;
 967                 } else {
 968                         // If created via makeTitle(), $this->mUserCaseDBKey is not set.
 969                         return $this->mDbkeyform;
 970                 }
 971         }
 972
 973         /**
 974          * Get the namespace index, i.e. one of the NS_xxxx constants.
 975          *
 976          * @return int Namespace index
 977          */
 978         public function getNamespace() {
 979                 return $this->mNamespace;
 980         }
 981
 982         /**
 983          * Get the page's content model id, see the CONTENT_MODEL_XXX constants.
 984          *
 985          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
 986          * @return string Content model id
 987          */
 988         public function getContentModel( $flags = 0 ) {
 989                 if ( !$this->mForcedContentModel
 990                         && ( !$this->mContentModel || $flags === self::GAID_FOR_UPDATE )
 991                         && $this->getArticleID( $flags )
 992                 ) {
 993                         $linkCache = LinkCache::singleton();
 994                         $linkCache->addLinkObj( $this ); # in case we already had an article ID
 995                         $this->mContentModel = $linkCache->getGoodLinkFieldObj( $this, 'model' );
 996                 }
 997
 998                 if ( !$this->mContentModel ) {
 999                         $this->mContentModel = ContentHandler::getDefaultModelFor( $this );
1000                 }
1001
1002                 return $this->mContentModel;
1003         }
1004
1005         /**
1006          * Convenience method for checking a title's content model name
1007          *
1008          * @param string $id The content model ID (use the CONTENT_MODEL_XXX constants).
1009          * @return bool True if $this->getContentModel() == $id
1010          */
1011         public function hasContentModel( $id ) {
1012                 return $this->getContentModel() == $id;
1013         }
1014
1015         /**
1016          * Set a proposed content model for the page for permissions
1017          * checking. This does not actually change the content model
1018          * of a title!
1019          *
1020          * Additionally, you should make sure you've checked
1021          * ContentHandler::canBeUsedOn() first.
1022          *
1023          * @since 1.28
1024          * @param string $model CONTENT_MODEL_XXX constant
1025          */
1026         public function setContentModel( $model ) {
1027                 $this->mContentModel = $model;
1028                 $this->mForcedContentModel = true;
1029         }
1030
1031         /**
1032          * Get the namespace text
1033          *
1034          * @return string|false Namespace text
1035          */
1036         public function getNsText() {
1037                 if ( $this->isExternal() ) {
1038                         // This probably shouldn't even happen,
1039                         // but for interwiki transclusion it sometimes does.
1040                         // Use the canonical namespaces if possible to try to
1041                         // resolve a foreign namespace.
1042                         if ( MWNamespace::exists( $this->mNamespace ) ) {
1043                                 return MWNamespace::getCanonicalName( $this->mNamespace );
1044                         }
1045                 }
1046
1047                 try {
1048                         $formatter = self::getTitleFormatter();
1049                         return $formatter->getNamespaceName( $this->mNamespace, $this->mDbkeyform );
1050                 } catch ( InvalidArgumentException $ex ) {
1051                         wfDebug( __METHOD__ . ': ' . $ex->getMessage() . "\n" );
1052                         return false;
1053                 }
1054         }
1055
1056         /**
1057          * Get the namespace text of the subject (rather than talk) page
1058          *
1059          * @return string Namespace text
1060          */
1061         public function getSubjectNsText() {
1062                 global $wgContLang;
1063                 return $wgContLang->getNsText( MWNamespace::getSubject( $this->mNamespace ) );
1064         }
1065
1066         /**
1067          * Get the namespace text of the talk page
1068          *
1069          * @return string Namespace text
1070          */
1071         public function getTalkNsText() {
1072                 global $wgContLang;
1073                 return $wgContLang->getNsText( MWNamespace::getTalk( $this->mNamespace ) );
1074         }
1075
1076         /**
1077          * Can this title have a corresponding talk page?
1078          *
1079          * @deprecated since 1.30, use canHaveTalkPage() instead.
1080          *
1081          * @return bool True if this title either is a talk page or can have a talk page associated.
1082          */
1083         public function canTalk() {
1084                 return $this->canHaveTalkPage();
1085         }
1086
1087         /**
1088          * Can this title have a corresponding talk page?
1089          *
1090          * @see MWNamespace::hasTalkNamespace
1091          * @since 1.30
1092          *
1093          * @return bool True if this title either is a talk page or can have a talk page associated.
1094          */
1095         public function canHaveTalkPage() {
1096                 return MWNamespace::hasTalkNamespace( $this->mNamespace );
1097         }
1098
1099         /**
1100          * Is this in a namespace that allows actual pages?
1101          *
1102          * @return bool
1103          */
1104         public function canExist() {
1105                 return $this->mNamespace >= NS_MAIN;
1106         }
1107
1108         /**
1109          * Can this title be added to a user's watchlist?
1110          *
1111          * @return bool
1112          */
1113         public function isWatchable() {
1114                 return !$this->isExternal() && MWNamespace::isWatchable( $this->getNamespace() );
1115         }
1116
1117         /**
1118          * Returns true if this is a special page.
1119          *
1120          * @return bool
1121          */
1122         public function isSpecialPage() {
1123                 return $this->getNamespace() == NS_SPECIAL;
1124         }
1125
1126         /**
1127          * Returns true if this title resolves to the named special page
1128          *
1129          * @param string $name The special page name
1130          * @return bool
1131          */
1132         public function isSpecial( $name ) {
1133                 if ( $this->isSpecialPage() ) {
1134                         list( $thisName, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $this->getDBkey() );
1135                         if ( $name == $thisName ) {
1136                                 return true;
1137                         }
1138                 }
1139                 return false;
1140         }
1141
1142         /**
1143          * If the Title refers to a special page alias which is not the local default, resolve
1144          * the alias, and localise the name as necessary.  Otherwise, return $this
1145          *
1146          * @return Title
1147          */
1148         public function fixSpecialName() {
1149                 if ( $this->isSpecialPage() ) {
1150                         list( $canonicalName, $par ) = SpecialPageFactory::resolveAlias( $this->mDbkeyform );
1151                         if ( $canonicalName ) {
1152                                 $localName = SpecialPageFactory::getLocalNameFor( $canonicalName, $par );
1153                                 if ( $localName != $this->mDbkeyform ) {
1154                                         return self::makeTitle( NS_SPECIAL, $localName );
1155                                 }
1156                         }
1157                 }
1158                 return $this;
1159         }
1160
1161         /**
1162          * Returns true if the title is inside the specified namespace.
1163          *
1164          * Please make use of this instead of comparing to getNamespace()
1165          * This function is much more resistant to changes we may make
1166          * to namespaces than code that makes direct comparisons.
1167          * @param int $ns The namespace
1168          * @return bool
1169          * @since 1.19
1170          */
1171         public function inNamespace( $ns ) {
1172                 return MWNamespace::equals( $this->getNamespace(), $ns );
1173         }
1174
1175         /**
1176          * Returns true if the title is inside one of the specified namespaces.
1177          *
1178          * @param int|int[] $namespaces,... The namespaces to check for
1179          * @return bool
1180          * @since 1.19
1181          */
1182         public function inNamespaces( /* ... */ ) {
1183                 $namespaces = func_get_args();
1184                 if ( count( $namespaces ) > 0 && is_array( $namespaces[0] ) ) {
1185                         $namespaces = $namespaces[0];
1186                 }
1187
1188                 foreach ( $namespaces as $ns ) {
1189                         if ( $this->inNamespace( $ns ) ) {
1190                                 return true;
1191                         }
1192                 }
1193
1194                 return false;
1195         }
1196
1197         /**
1198          * Returns true if the title has the same subject namespace as the
1199          * namespace specified.
1200          * For example this method will take NS_USER and return true if namespace
1201          * is either NS_USER or NS_USER_TALK since both of them have NS_USER
1202          * as their subject namespace.
1203          *
1204          * This is MUCH simpler than individually testing for equivalence
1205          * against both NS_USER and NS_USER_TALK, and is also forward compatible.
1206          * @since 1.19
1207          * @param int $ns
1208          * @return bool
1209          */
1210         public function hasSubjectNamespace( $ns ) {
1211                 return MWNamespace::subjectEquals( $this->getNamespace(), $ns );
1212         }
1213
1214         /**
1215          * Is this Title in a namespace which contains content?
1216          * In other words, is this a content page, for the purposes of calculating
1217          * statistics, etc?
1218          *
1219          * @return bool
1220          */
1221         public function isContentPage() {
1222                 return MWNamespace::isContent( $this->getNamespace() );
1223         }
1224
1225         /**
1226          * Would anybody with sufficient privileges be able to move this page?
1227          * Some pages just aren't movable.
1228          *
1229          * @return bool
1230          */
1231         public function isMovable() {
1232                 if ( !MWNamespace::isMovable( $this->getNamespace() ) || $this->isExternal() ) {
1233                         // Interwiki title or immovable namespace. Hooks don't get to override here
1234                         return false;
1235                 }
1236
1237                 $result = true;
1238                 Hooks::run( 'TitleIsMovable', [ $this, &$result ] );
1239                 return $result;
1240         }
1241
1242         /**
1243          * Is this the mainpage?
1244          * @note Title::newFromText seems to be sufficiently optimized by the title
1245          * cache that we don't need to over-optimize by doing direct comparisons and
1246          * accidentally creating new bugs where $title->equals( Title::newFromText() )
1247          * ends up reporting something differently than $title->isMainPage();
1248          *
1249          * @since 1.18
1250          * @return bool
1251          */
1252         public function isMainPage() {
1253                 return $this->equals( self::newMainPage() );
1254         }
1255
1256         /**
1257          * Is this a subpage?
1258          *
1259          * @return bool
1260          */
1261         public function isSubpage() {
1262                 return MWNamespace::hasSubpages( $this->mNamespace )
1263                         ? strpos( $this->getText(), '/' ) !== false
1264                         : false;
1265         }
1266
1267         /**
1268          * Is this a conversion table for the LanguageConverter?
1269          *
1270          * @return bool
1271          */
1272         public function isConversionTable() {
1273                 // @todo ConversionTable should become a separate content model.
1274
1275                 return $this->getNamespace() == NS_MEDIAWIKI &&
1276                         strpos( $this->getText(), 'Conversiontable/' ) === 0;
1277         }
1278
1279         /**
1280          * Does that page contain wikitext, or it is JS, CSS or whatever?
1281          *
1282          * @return bool
1283          */
1284         public function isWikitextPage() {
1285                 return $this->hasContentModel( CONTENT_MODEL_WIKITEXT );
1286         }
1287
1288         /**
1289          * Could this page contain custom CSS or JavaScript for the global UI.
1290          * This is generally true for pages in the MediaWiki namespace having CONTENT_MODEL_CSS
1291          * or CONTENT_MODEL_JAVASCRIPT.
1292          *
1293          * This method does *not* return true for per-user JS/CSS. Use isCssJsSubpage()
1294          * for that!
1295          *
1296          * Note that this method should not return true for pages that contain and
1297          * show "inactive" CSS or JS.
1298          *
1299          * @return bool
1300          * @todo FIXME: Rename to isSiteConfigPage() and remove deprecated hook
1301          */
1302         public function isCssOrJsPage() {
1303                 $isCssOrJsPage = NS_MEDIAWIKI == $this->mNamespace
1304                         && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1305                                 || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1306
1307                 return $isCssOrJsPage;
1308         }
1309
1310         /**
1311          * Is this a .css or .js subpage of a user page?
1312          * @return bool
1313          * @todo FIXME: Rename to isUserConfigPage()
1314          */
1315         public function isCssJsSubpage() {
1316                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1317                                 && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1318                                         || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) ) );
1319         }
1320
1321         /**
1322          * Trim down a .css or .js subpage title to get the corresponding skin name
1323          *
1324          * @return string Containing skin name from .css or .js subpage title
1325          */
1326         public function getSkinFromCssJsSubpage() {
1327                 $subpage = explode( '/', $this->mTextform );
1328                 $subpage = $subpage[count( $subpage ) - 1];
1329                 $lastdot = strrpos( $subpage, '.' );
1330                 if ( $lastdot === false ) {
1331                         return $subpage; # Never happens: only called for names ending in '.css' or '.js'
1332                 }
1333                 return substr( $subpage, 0, $lastdot );
1334         }
1335
1336         /**
1337          * Is this a .css subpage of a user page?
1338          *
1339          * @return bool
1340          */
1341         public function isCssSubpage() {
1342                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1343                         && $this->hasContentModel( CONTENT_MODEL_CSS ) );
1344         }
1345
1346         /**
1347          * Is this a .js subpage of a user page?
1348          *
1349          * @return bool
1350          */
1351         public function isJsSubpage() {
1352                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1353                         && $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1354         }
1355
1356         /**
1357          * Is this a talk page of some sort?
1358          *
1359          * @return bool
1360          */
1361         public function isTalkPage() {
1362                 return MWNamespace::isTalk( $this->getNamespace() );
1363         }
1364
1365         /**
1366          * Get a Title object associated with the talk page of this article
1367          *
1368          * @return Title The object for the talk page
1369          */
1370         public function getTalkPage() {
1371                 return self::makeTitle( MWNamespace::getTalk( $this->getNamespace() ), $this->getDBkey() );
1372         }
1373
1374         /**
1375          * Get a Title object associated with the talk page of this article,
1376          * if such a talk page can exist.
1377          *
1378          * @since 1.30
1379          *
1380          * @return Title|null The object for the talk page,
1381          *         or null if no associated talk page can exist, according to canHaveTalkPage().
1382          */
1383         public function getTalkPageIfDefined() {
1384                 if ( !$this->canHaveTalkPage() ) {
1385                         return null;
1386                 }
1387
1388                 return $this->getTalkPage();
1389         }
1390
1391         /**
1392          * Get a title object associated with the subject page of this
1393          * talk page
1394          *
1395          * @return Title The object for the subject page
1396          */
1397         public function getSubjectPage() {
1398                 // Is this the same title?
1399                 $subjectNS = MWNamespace::getSubject( $this->getNamespace() );
1400                 if ( $this->getNamespace() == $subjectNS ) {
1401                         return $this;
1402                 }
1403                 return self::makeTitle( $subjectNS, $this->getDBkey() );
1404         }
1405
1406         /**
1407          * Get the other title for this page, if this is a subject page
1408          * get the talk page, if it is a subject page get the talk page
1409          *
1410          * @since 1.25
1411          * @throws MWException If the page doesn't have an other page
1412          * @return Title
1413          */
1414         public function getOtherPage() {
1415                 if ( $this->isSpecialPage() ) {
1416                         throw new MWException( 'Special pages cannot have other pages' );
1417                 }
1418                 if ( $this->isTalkPage() ) {
1419                         return $this->getSubjectPage();
1420                 } else {
1421                         if ( !$this->canHaveTalkPage() ) {
1422                                 throw new MWException( "{$this->getPrefixedText()} does not have an other page" );
1423                         }
1424                         return $this->getTalkPage();
1425                 }
1426         }
1427
1428         /**
1429          * Get the default namespace index, for when there is no namespace
1430          *
1431          * @return int Default namespace index
1432          */
1433         public function getDefaultNamespace() {
1434                 return $this->mDefaultNamespace;
1435         }
1436
1437         /**
1438          * Get the Title fragment (i.e.\ the bit after the #) in text form
1439          *
1440          * Use Title::hasFragment to check for a fragment
1441          *
1442          * @return string Title fragment
1443          */
1444         public function getFragment() {
1445                 return $this->mFragment;
1446         }
1447
1448         /**
1449          * Check if a Title fragment is set
1450          *
1451          * @return bool
1452          * @since 1.23
1453          */
1454         public function hasFragment() {
1455                 return $this->mFragment !== '';
1456         }
1457
1458         /**
1459          * Get the fragment in URL form, including the "#" character if there is one
1460          *
1461          * @return string Fragment in URL form
1462          */
1463         public function getFragmentForURL() {
1464                 if ( !$this->hasFragment() ) {
1465                         return '';
1466                 } elseif ( $this->isExternal() && !$this->getTransWikiID() ) {
1467                         return '#' . Sanitizer::escapeIdForExternalInterwiki( $this->getFragment() );
1468                 }
1469                 return '#' . Sanitizer::escapeIdForLink( $this->getFragment() );
1470         }
1471
1472         /**
1473          * Set the fragment for this title. Removes the first character from the
1474          * specified fragment before setting, so it assumes you're passing it with
1475          * an initial "#".
1476          *
1477          * Deprecated for public use, use Title::makeTitle() with fragment parameter,
1478          * or Title::createFragmentTarget().
1479          * Still in active use privately.
1480          *
1481          * @private
1482          * @param string $fragment Text
1483          */
1484         public function setFragment( $fragment ) {
1485                 $this->mFragment = strtr( substr( $fragment, 1 ), '_', ' ' );
1486         }
1487
1488         /**
1489          * Creates a new Title for a different fragment of the same page.
1490          *
1491          * @since 1.27
1492          * @param string $fragment
1493          * @return Title
1494          */
1495         public function createFragmentTarget( $fragment ) {
1496                 return self::makeTitle(
1497                         $this->getNamespace(),
1498                         $this->getText(),
1499                         $fragment,
1500                         $this->getInterwiki()
1501                 );
1502         }
1503
1504         /**
1505          * Prefix some arbitrary text with the namespace or interwiki prefix
1506          * of this object
1507          *
1508          * @param string $name The text
1509          * @return string The prefixed text
1510          */
1511         private function prefix( $name ) {
1512                 global $wgContLang;
1513
1514                 $p = '';
1515                 if ( $this->isExternal() ) {
1516                         $p = $this->mInterwiki . ':';
1517                 }
1518
1519                 if ( 0 != $this->mNamespace ) {
1520                         $nsText = $this->getNsText();
1521
1522                         if ( $nsText === false ) {
1523                                 // See T165149. Awkward, but better than erroneously linking to the main namespace.
1524                                 $nsText = $wgContLang->getNsText( NS_SPECIAL ) . ":Badtitle/NS{$this->mNamespace}";
1525                         }
1526
1527                         $p .= $nsText . ':';
1528                 }
1529                 return $p . $name;
1530         }
1531
1532         /**
1533          * Get the prefixed database key form
1534          *
1535          * @return string The prefixed title, with underscores and
1536          *  any interwiki and namespace prefixes
1537          */
1538         public function getPrefixedDBkey() {
1539                 $s = $this->prefix( $this->mDbkeyform );
1540                 $s = strtr( $s, ' ', '_' );
1541                 return $s;
1542         }
1543
1544         /**
1545          * Get the prefixed title with spaces.
1546          * This is the form usually used for display
1547          *
1548          * @return string The prefixed title, with spaces
1549          */
1550         public function getPrefixedText() {
1551                 if ( $this->mPrefixedText === null ) {
1552                         $s = $this->prefix( $this->mTextform );
1553                         $s = strtr( $s, '_', ' ' );
1554                         $this->mPrefixedText = $s;
1555                 }
1556                 return $this->mPrefixedText;
1557         }
1558
1559         /**
1560          * Return a string representation of this title
1561          *
1562          * @return string Representation of this title
1563          */
1564         public function __toString() {
1565                 return $this->getPrefixedText();
1566         }
1567
1568         /**
1569          * Get the prefixed title with spaces, plus any fragment
1570          * (part beginning with '#')
1571          *
1572          * @return string The prefixed title, with spaces and the fragment, including '#'
1573          */
1574         public function getFullText() {
1575                 $text = $this->getPrefixedText();
1576                 if ( $this->hasFragment() ) {
1577                         $text .= '#' . $this->getFragment();
1578                 }
1579                 return $text;
1580         }
1581
1582         /**
1583          * Get the root page name text without a namespace, i.e. the leftmost part before any slashes
1584          *
1585          * @par Example:
1586          * @code
1587          * Title::newFromText('User:Foo/Bar/Baz')->getRootText();
1588          * # returns: 'Foo'
1589          * @endcode
1590          *
1591          * @return string Root name
1592          * @since 1.20
1593          */
1594         public function getRootText() {
1595                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1596                         return $this->getText();
1597                 }
1598
1599                 return strtok( $this->getText(), '/' );
1600         }
1601
1602         /**
1603          * Get the root page name title, i.e. the leftmost part before any slashes
1604          *
1605          * @par Example:
1606          * @code
1607          * Title::newFromText('User:Foo/Bar/Baz')->getRootTitle();
1608          * # returns: Title{User:Foo}
1609          * @endcode
1610          *
1611          * @return Title Root title
1612          * @since 1.20
1613          */
1614         public function getRootTitle() {
1615                 return self::makeTitle( $this->getNamespace(), $this->getRootText() );
1616         }
1617
1618         /**
1619          * Get the base page name without a namespace, i.e. the part before the subpage name
1620          *
1621          * @par Example:
1622          * @code
1623          * Title::newFromText('User:Foo/Bar/Baz')->getBaseText();
1624          * # returns: 'Foo/Bar'
1625          * @endcode
1626          *
1627          * @return string Base name
1628          */
1629         public function getBaseText() {
1630                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1631                         return $this->getText();
1632                 }
1633
1634                 $parts = explode( '/', $this->getText() );
1635                 # Don't discard the real title if there's no subpage involved
1636                 if ( count( $parts ) > 1 ) {
1637                         unset( $parts[count( $parts ) - 1] );
1638                 }
1639                 return implode( '/', $parts );
1640         }
1641
1642         /**
1643          * Get the base page name title, i.e. the part before the subpage name
1644          *
1645          * @par Example:
1646          * @code
1647          * Title::newFromText('User:Foo/Bar/Baz')->getBaseTitle();
1648          * # returns: Title{User:Foo/Bar}
1649          * @endcode
1650          *
1651          * @return Title Base title
1652          * @since 1.20
1653          */
1654         public function getBaseTitle() {
1655                 return self::makeTitle( $this->getNamespace(), $this->getBaseText() );
1656         }
1657
1658         /**
1659          * Get the lowest-level subpage name, i.e. the rightmost part after any slashes
1660          *
1661          * @par Example:
1662          * @code
1663          * Title::newFromText('User:Foo/Bar/Baz')->getSubpageText();
1664          * # returns: "Baz"
1665          * @endcode
1666          *
1667          * @return string Subpage name
1668          */
1669         public function getSubpageText() {
1670                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1671                         return $this->mTextform;
1672                 }
1673                 $parts = explode( '/', $this->mTextform );
1674                 return $parts[count( $parts ) - 1];
1675         }
1676
1677         /**
1678          * Get the title for a subpage of the current page
1679          *
1680          * @par Example:
1681          * @code
1682          * Title::newFromText('User:Foo/Bar/Baz')->getSubpage("Asdf");
1683          * # returns: Title{User:Foo/Bar/Baz/Asdf}
1684          * @endcode
1685          *
1686          * @param string $text The subpage name to add to the title
1687          * @return Title Subpage title
1688          * @since 1.20
1689          */
1690         public function getSubpage( $text ) {
1691                 return self::makeTitleSafe( $this->getNamespace(), $this->getText() . '/' . $text );
1692         }
1693
1694         /**
1695          * Get a URL-encoded form of the subpage text
1696          *
1697          * @return string URL-encoded subpage name
1698          */
1699         public function getSubpageUrlForm() {
1700                 $text = $this->getSubpageText();
1701                 $text = wfUrlencode( strtr( $text, ' ', '_' ) );
1702                 return $text;
1703         }
1704
1705         /**
1706          * Get a URL-encoded title (not an actual URL) including interwiki
1707          *
1708          * @return string The URL-encoded form
1709          */
1710         public function getPrefixedURL() {
1711                 $s = $this->prefix( $this->mDbkeyform );
1712                 $s = wfUrlencode( strtr( $s, ' ', '_' ) );
1713                 return $s;
1714         }
1715
1716         /**
1717          * Helper to fix up the get{Canonical,Full,Link,Local,Internal}URL args
1718          * get{Canonical,Full,Link,Local,Internal}URL methods accepted an optional
1719          * second argument named variant. This was deprecated in favor
1720          * of passing an array of option with a "variant" key
1721          * Once $query2 is removed for good, this helper can be dropped
1722          * and the wfArrayToCgi moved to getLocalURL();
1723          *
1724          * @since 1.19 (r105919)
1725          * @param array|string $query
1726          * @param string|string[]|bool $query2
1727          * @return string
1728          */
1729         private static function fixUrlQueryArgs( $query, $query2 = false ) {
1730                 if ( $query2 !== false ) {
1731                         wfDeprecated( "Title::get{Canonical,Full,Link,Local,Internal}URL " .
1732                                 "method called with a second parameter is deprecated. Add your " .
1733                                 "parameter to an array passed as the first parameter.", "1.19" );
1734                 }
1735                 if ( is_array( $query ) ) {
1736                         $query = wfArrayToCgi( $query );
1737                 }
1738                 if ( $query2 ) {
1739                         if ( is_string( $query2 ) ) {
1740                                 // $query2 is a string, we will consider this to be
1741                                 // a deprecated $variant argument and add it to the query
1742                                 $query2 = wfArrayToCgi( [ 'variant' => $query2 ] );
1743                         } else {
1744                                 $query2 = wfArrayToCgi( $query2 );
1745                         }
1746                         // If we have $query content add a & to it first
1747                         if ( $query ) {
1748                                 $query .= '&';
1749                         }
1750                         // Now append the queries together
1751                         $query .= $query2;
1752                 }
1753                 return $query;
1754         }
1755
1756         /**
1757          * Get a real URL referring to this title, with interwiki link and
1758          * fragment
1759          *
1760          * @see self::getLocalURL for the arguments.
1761          * @see wfExpandUrl
1762          * @param string|string[] $query
1763          * @param string|string[]|bool $query2
1764          * @param string $proto Protocol type to use in URL
1765          * @return string The URL
1766          */
1767         public function getFullURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1768                 $query = self::fixUrlQueryArgs( $query, $query2 );
1769
1770                 # Hand off all the decisions on urls to getLocalURL
1771                 $url = $this->getLocalURL( $query );
1772
1773                 # Expand the url to make it a full url. Note that getLocalURL has the
1774                 # potential to output full urls for a variety of reasons, so we use
1775                 # wfExpandUrl instead of simply prepending $wgServer
1776                 $url = wfExpandUrl( $url, $proto );
1777
1778                 # Finally, add the fragment.
1779                 $url .= $this->getFragmentForURL();
1780                 // Avoid PHP 7.1 warning from passing $this by reference
1781                 $titleRef = $this;
1782                 Hooks::run( 'GetFullURL', [ &$titleRef, &$url, $query ] );
1783                 return $url;
1784         }
1785
1786         /**
1787          * Get a url appropriate for making redirects based on an untrusted url arg
1788          *
1789          * This is basically the same as getFullUrl(), but in the case of external
1790          * interwikis, we send the user to a landing page, to prevent possible
1791          * phishing attacks and the like.
1792          *
1793          * @note Uses current protocol by default, since technically relative urls
1794          *   aren't allowed in redirects per HTTP spec, so this is not suitable for
1795          *   places where the url gets cached, as might pollute between
1796          *   https and non-https users.
1797          * @see self::getLocalURL for the arguments.
1798          * @param array|string $query
1799          * @param string $proto Protocol type to use in URL
1800          * @return String. A url suitable to use in an HTTP location header.
1801          */
1802         public function getFullUrlForRedirect( $query = '', $proto = PROTO_CURRENT ) {
1803                 $target = $this;
1804                 if ( $this->isExternal() ) {
1805                         $target = SpecialPage::getTitleFor(
1806                                 'GoToInterwiki',
1807                                 $this->getPrefixedDBKey()
1808                         );
1809                 }
1810                 return $target->getFullUrl( $query, false, $proto );
1811         }
1812
1813         /**
1814          * Get a URL with no fragment or server name (relative URL) from a Title object.
1815          * If this page is generated with action=render, however,
1816          * $wgServer is prepended to make an absolute URL.
1817          *
1818          * @see self::getFullURL to always get an absolute URL.
1819          * @see self::getLinkURL to always get a URL that's the simplest URL that will be
1820          *  valid to link, locally, to the current Title.
1821          * @see self::newFromText to produce a Title object.
1822          *
1823          * @param string|string[] $query An optional query string,
1824          *   not used for interwiki links. Can be specified as an associative array as well,
1825          *   e.g., array( 'action' => 'edit' ) (keys and values will be URL-escaped).
1826          *   Some query patterns will trigger various shorturl path replacements.
1827          * @param string|string[]|bool $query2 An optional secondary query array. This one MUST
1828          *   be an array. If a string is passed it will be interpreted as a deprecated
1829          *   variant argument and urlencoded into a variant= argument.
1830          *   This second query argument will be added to the $query
1831          *   The second parameter is deprecated since 1.19. Pass it as a key,value
1832          *   pair in the first parameter array instead.
1833          *
1834          * @return string String of the URL.
1835          */
1836         public function getLocalURL( $query = '', $query2 = false ) {
1837                 global $wgArticlePath, $wgScript, $wgServer, $wgRequest;
1838
1839                 $query = self::fixUrlQueryArgs( $query, $query2 );
1840
1841                 $interwiki = self::getInterwikiLookup()->fetch( $this->mInterwiki );
1842                 if ( $interwiki ) {
1843                         $namespace = $this->getNsText();
1844                         if ( $namespace != '' ) {
1845                                 # Can this actually happen? Interwikis shouldn't be parsed.
1846                                 # Yes! It can in interwiki transclusion. But... it probably shouldn't.
1847                                 $namespace .= ':';
1848                         }
1849                         $url = $interwiki->getURL( $namespace . $this->getDBkey() );
1850                         $url = wfAppendQuery( $url, $query );
1851                 } else {
1852                         $dbkey = wfUrlencode( $this->getPrefixedDBkey() );
1853                         if ( $query == '' ) {
1854                                 $url = str_replace( '$1', $dbkey, $wgArticlePath );
1855                                 // Avoid PHP 7.1 warning from passing $this by reference
1856                                 $titleRef = $this;
1857                                 Hooks::run( 'GetLocalURL::Article', [ &$titleRef, &$url ] );
1858                         } else {
1859                                 global $wgVariantArticlePath, $wgActionPaths, $wgContLang;
1860                                 $url = false;
1861                                 $matches = [];
1862
1863                                 if ( !empty( $wgActionPaths )
1864                                         && preg_match( '/^(.*&|)action=([^&]*)(&(.*)|)$/', $query, $matches )
1865                                 ) {
1866                                         $action = urldecode( $matches[2] );
1867                                         if ( isset( $wgActionPaths[$action] ) ) {
1868                                                 $query = $matches[1];
1869                                                 if ( isset( $matches[4] ) ) {
1870                                                         $query .= $matches[4];
1871                                                 }
1872                                                 $url = str_replace( '$1', $dbkey, $wgActionPaths[$action] );
1873                                                 if ( $query != '' ) {
1874                                                         $url = wfAppendQuery( $url, $query );
1875                                                 }
1876                                         }
1877                                 }
1878
1879                                 if ( $url === false
1880                                         && $wgVariantArticlePath
1881                                         && preg_match( '/^variant=([^&]*)$/', $query, $matches )
1882                                         && $this->getPageLanguage()->equals( $wgContLang )
1883                                         && $this->getPageLanguage()->hasVariants()
1884                                 ) {
1885                                         $variant = urldecode( $matches[1] );
1886                                         if ( $this->getPageLanguage()->hasVariant( $variant ) ) {
1887                                                 // Only do the variant replacement if the given variant is a valid
1888                                                 // variant for the page's language.
1889                                                 $url = str_replace( '$2', urlencode( $variant ), $wgVariantArticlePath );
1890                                                 $url = str_replace( '$1', $dbkey, $url );
1891                                         }
1892                                 }
1893
1894                                 if ( $url === false ) {
1895                                         if ( $query == '-' ) {
1896                                                 $query = '';
1897                                         }
1898                                         $url = "{$wgScript}?title={$dbkey}&{$query}";
1899                                 }
1900                         }
1901                         // Avoid PHP 7.1 warning from passing $this by reference
1902                         $titleRef = $this;
1903                         Hooks::run( 'GetLocalURL::Internal', [ &$titleRef, &$url, $query ] );
1904
1905                         // @todo FIXME: This causes breakage in various places when we
1906                         // actually expected a local URL and end up with dupe prefixes.
1907                         if ( $wgRequest->getVal( 'action' ) == 'render' ) {
1908                                 $url = $wgServer . $url;
1909                         }
1910                 }
1911                 // Avoid PHP 7.1 warning from passing $this by reference
1912                 $titleRef = $this;
1913                 Hooks::run( 'GetLocalURL', [ &$titleRef, &$url, $query ] );
1914                 return $url;
1915         }
1916
1917         /**
1918          * Get a URL that's the simplest URL that will be valid to link, locally,
1919          * to the current Title.  It includes the fragment, but does not include
1920          * the server unless action=render is used (or the link is external).  If
1921          * there's a fragment but the prefixed text is empty, we just return a link
1922          * to the fragment.
1923          *
1924          * The result obviously should not be URL-escaped, but does need to be
1925          * HTML-escaped if it's being output in HTML.
1926          *
1927          * @param string|string[] $query
1928          * @param bool $query2
1929          * @param string|int|bool $proto A PROTO_* constant on how the URL should be expanded,
1930          *                               or false (default) for no expansion
1931          * @see self::getLocalURL for the arguments.
1932          * @return string The URL
1933          */
1934         public function getLinkURL( $query = '', $query2 = false, $proto = false ) {
1935                 if ( $this->isExternal() || $proto !== false ) {
1936                         $ret = $this->getFullURL( $query, $query2, $proto );
1937                 } elseif ( $this->getPrefixedText() === '' && $this->hasFragment() ) {
1938                         $ret = $this->getFragmentForURL();
1939                 } else {
1940                         $ret = $this->getLocalURL( $query, $query2 ) . $this->getFragmentForURL();
1941                 }
1942                 return $ret;
1943         }
1944
1945         /**
1946          * Get the URL form for an internal link.
1947          * - Used in various CDN-related code, in case we have a different
1948          * internal hostname for the server from the exposed one.
1949          *
1950          * This uses $wgInternalServer to qualify the path, or $wgServer
1951          * if $wgInternalServer is not set. If the server variable used is
1952          * protocol-relative, the URL will be expanded to http://
1953          *
1954          * @see self::getLocalURL for the arguments.
1955          * @param string $query
1956          * @param string|bool $query2
1957          * @return string The URL
1958          */
1959         public function getInternalURL( $query = '', $query2 = false ) {
1960                 global $wgInternalServer, $wgServer;
1961                 $query = self::fixUrlQueryArgs( $query, $query2 );
1962                 $server = $wgInternalServer !== false ? $wgInternalServer : $wgServer;
1963                 $url = wfExpandUrl( $server . $this->getLocalURL( $query ), PROTO_HTTP );
1964                 // Avoid PHP 7.1 warning from passing $this by reference
1965                 $titleRef = $this;
1966                 Hooks::run( 'GetInternalURL', [ &$titleRef, &$url, $query ] );
1967                 return $url;
1968         }
1969
1970         /**
1971          * Get the URL for a canonical link, for use in things like IRC and
1972          * e-mail notifications. Uses $wgCanonicalServer and the
1973          * GetCanonicalURL hook.
1974          *
1975          * NOTE: Unlike getInternalURL(), the canonical URL includes the fragment
1976          *
1977          * @see self::getLocalURL for the arguments.
1978          * @return string The URL
1979          * @since 1.18
1980          */
1981         public function getCanonicalURL( $query = '', $query2 = false ) {
1982                 $query = self::fixUrlQueryArgs( $query, $query2 );
1983                 $url = wfExpandUrl( $this->getLocalURL( $query ) . $this->getFragmentForURL(), PROTO_CANONICAL );
1984                 // Avoid PHP 7.1 warning from passing $this by reference
1985                 $titleRef = $this;
1986                 Hooks::run( 'GetCanonicalURL', [ &$titleRef, &$url, $query ] );
1987                 return $url;
1988         }
1989
1990         /**
1991          * Get the edit URL for this Title
1992          *
1993          * @return string The URL, or a null string if this is an interwiki link
1994          */
1995         public function getEditURL() {
1996                 if ( $this->isExternal() ) {
1997                         return '';
1998                 }
1999                 $s = $this->getLocalURL( 'action=edit' );
2000
2001                 return $s;
2002         }
2003
2004         /**
2005          * Can $user perform $action on this page?
2006          * This skips potentially expensive cascading permission checks
2007          * as well as avoids expensive error formatting
2008          *
2009          * Suitable for use for nonessential UI controls in common cases, but
2010          * _not_ for functional access control.
2011          *
2012          * May provide false positives, but should never provide a false negative.
2013          *
2014          * @param string $action Action that permission needs to be checked for
2015          * @param User $user User to check (since 1.19); $wgUser will be used if not provided.
2016          * @return bool
2017          */
2018         public function quickUserCan( $action, $user = null ) {
2019                 return $this->userCan( $action, $user, false );
2020         }
2021
2022         /**
2023          * Can $user perform $action on this page?
2024          *
2025          * @param string $action Action that permission needs to be checked for
2026          * @param User $user User to check (since 1.19); $wgUser will be used if not
2027          *   provided.
2028          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2029          * @return bool
2030          */
2031         public function userCan( $action, $user = null, $rigor = 'secure' ) {
2032                 if ( !$user instanceof User ) {
2033                         global $wgUser;
2034                         $user = $wgUser;
2035                 }
2036
2037                 return !count( $this->getUserPermissionsErrorsInternal( $action, $user, $rigor, true ) );
2038         }
2039
2040         /**
2041          * Can $user perform $action on this page?
2042          *
2043          * @todo FIXME: This *does not* check throttles (User::pingLimiter()).
2044          *
2045          * @param string $action Action that permission needs to be checked for
2046          * @param User $user User to check
2047          * @param string $rigor One of (quick,full,secure)
2048          *   - quick  : does cheap permission checks from replica DBs (usable for GUI creation)
2049          *   - full   : does cheap and expensive checks possibly from a replica DB
2050          *   - secure : does cheap and expensive checks, using the master as needed
2051          * @param array $ignoreErrors Array of Strings Set this to a list of message keys
2052          *   whose corresponding errors may be ignored.
2053          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
2054          */
2055         public function getUserPermissionsErrors(
2056                 $action, $user, $rigor = 'secure', $ignoreErrors = []
2057         ) {
2058                 $errors = $this->getUserPermissionsErrorsInternal( $action, $user, $rigor );
2059
2060                 // Remove the errors being ignored.
2061                 foreach ( $errors as $index => $error ) {
2062                         $errKey = is_array( $error ) ? $error[0] : $error;
2063
2064                         if ( in_array( $errKey, $ignoreErrors ) ) {
2065                                 unset( $errors[$index] );
2066                         }
2067                         if ( $errKey instanceof MessageSpecifier && in_array( $errKey->getKey(), $ignoreErrors ) ) {
2068                                 unset( $errors[$index] );
2069                         }
2070                 }
2071
2072                 return $errors;
2073         }
2074
2075         /**
2076          * Permissions checks that fail most often, and which are easiest to test.
2077          *
2078          * @param string $action The action to check
2079          * @param User $user User to check
2080          * @param array $errors List of current errors
2081          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2082          * @param bool $short Short circuit on first error
2083          *
2084          * @return array List of errors
2085          */
2086         private function checkQuickPermissions( $action, $user, $errors, $rigor, $short ) {
2087                 if ( !Hooks::run( 'TitleQuickPermissions',
2088                         [ $this, $user, $action, &$errors, ( $rigor !== 'quick' ), $short ] )
2089                 ) {
2090                         return $errors;
2091                 }
2092
2093                 if ( $action == 'create' ) {
2094                         if (
2095                                 ( $this->isTalkPage() && !$user->isAllowed( 'createtalk' ) ) ||
2096                                 ( !$this->isTalkPage() && !$user->isAllowed( 'createpage' ) )
2097                         ) {
2098                                 $errors[] = $user->isAnon() ? [ 'nocreatetext' ] : [ 'nocreate-loggedin' ];
2099                         }
2100                 } elseif ( $action == 'move' ) {
2101                         if ( !$user->isAllowed( 'move-rootuserpages' )
2102                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
2103                                 // Show user page-specific message only if the user can move other pages
2104                                 $errors[] = [ 'cant-move-user-page' ];
2105                         }
2106
2107                         // Check if user is allowed to move files if it's a file
2108                         if ( $this->mNamespace == NS_FILE && !$user->isAllowed( 'movefile' ) ) {
2109                                 $errors[] = [ 'movenotallowedfile' ];
2110                         }
2111
2112                         // Check if user is allowed to move category pages if it's a category page
2113                         if ( $this->mNamespace == NS_CATEGORY && !$user->isAllowed( 'move-categorypages' ) ) {
2114                                 $errors[] = [ 'cant-move-category-page' ];
2115                         }
2116
2117                         if ( !$user->isAllowed( 'move' ) ) {
2118                                 // User can't move anything
2119                                 $userCanMove = User::groupHasPermission( 'user', 'move' );
2120                                 $autoconfirmedCanMove = User::groupHasPermission( 'autoconfirmed', 'move' );
2121                                 if ( $user->isAnon() && ( $userCanMove || $autoconfirmedCanMove ) ) {
2122                                         // custom message if logged-in users without any special rights can move
2123                                         $errors[] = [ 'movenologintext' ];
2124                                 } else {
2125                                         $errors[] = [ 'movenotallowed' ];
2126                                 }
2127                         }
2128                 } elseif ( $action == 'move-target' ) {
2129                         if ( !$user->isAllowed( 'move' ) ) {
2130                                 // User can't move anything
2131                                 $errors[] = [ 'movenotallowed' ];
2132                         } elseif ( !$user->isAllowed( 'move-rootuserpages' )
2133                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
2134                                 // Show user page-specific message only if the user can move other pages
2135                                 $errors[] = [ 'cant-move-to-user-page' ];
2136                         } elseif ( !$user->isAllowed( 'move-categorypages' )
2137                                         && $this->mNamespace == NS_CATEGORY ) {
2138                                 // Show category page-specific message only if the user can move other pages
2139                                 $errors[] = [ 'cant-move-to-category-page' ];
2140                         }
2141                 } elseif ( !$user->isAllowed( $action ) ) {
2142                         $errors[] = $this->missingPermissionError( $action, $short );
2143                 }
2144
2145                 return $errors;
2146         }
2147
2148         /**
2149          * Add the resulting error code to the errors array
2150          *
2151          * @param array $errors List of current errors
2152          * @param array $result Result of errors
2153          *
2154          * @return array List of errors
2155          */
2156         private function resultToError( $errors, $result ) {
2157                 if ( is_array( $result ) && count( $result ) && !is_array( $result[0] ) ) {
2158                         // A single array representing an error
2159                         $errors[] = $result;
2160                 } elseif ( is_array( $result ) && is_array( $result[0] ) ) {
2161                         // A nested array representing multiple errors
2162                         $errors = array_merge( $errors, $result );
2163                 } elseif ( $result !== '' && is_string( $result ) ) {
2164                         // A string representing a message-id
2165                         $errors[] = [ $result ];
2166                 } elseif ( $result instanceof MessageSpecifier ) {
2167                         // A message specifier representing an error
2168                         $errors[] = [ $result ];
2169                 } elseif ( $result === false ) {
2170                         // a generic "We don't want them to do that"
2171                         $errors[] = [ 'badaccess-group0' ];
2172                 }
2173                 return $errors;
2174         }
2175
2176         /**
2177          * Check various permission hooks
2178          *
2179          * @param string $action The action to check
2180          * @param User $user User to check
2181          * @param array $errors List of current errors
2182          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2183          * @param bool $short Short circuit on first error
2184          *
2185          * @return array List of errors
2186          */
2187         private function checkPermissionHooks( $action, $user, $errors, $rigor, $short ) {
2188                 // Use getUserPermissionsErrors instead
2189                 $result = '';
2190                 // Avoid PHP 7.1 warning from passing $this by reference
2191                 $titleRef = $this;
2192                 if ( !Hooks::run( 'userCan', [ &$titleRef, &$user, $action, &$result ] ) ) {
2193                         return $result ? [] : [ [ 'badaccess-group0' ] ];
2194                 }
2195                 // Check getUserPermissionsErrors hook
2196                 // Avoid PHP 7.1 warning from passing $this by reference
2197                 $titleRef = $this;
2198                 if ( !Hooks::run( 'getUserPermissionsErrors', [ &$titleRef, &$user, $action, &$result ] ) ) {
2199                         $errors = $this->resultToError( $errors, $result );
2200                 }
2201                 // Check getUserPermissionsErrorsExpensive hook
2202                 if (
2203                         $rigor !== 'quick'
2204                         && !( $short && count( $errors ) > 0 )
2205                         && !Hooks::run( 'getUserPermissionsErrorsExpensive', [ &$titleRef, &$user, $action, &$result ] )
2206                 ) {
2207                         $errors = $this->resultToError( $errors, $result );
2208                 }
2209
2210                 return $errors;
2211         }
2212
2213         /**
2214          * Check permissions on special pages & namespaces
2215          *
2216          * @param string $action The action to check
2217          * @param User $user User to check
2218          * @param array $errors List of current errors
2219          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2220          * @param bool $short Short circuit on first error
2221          *
2222          * @return array List of errors
2223          */
2224         private function checkSpecialsAndNSPermissions( $action, $user, $errors, $rigor, $short ) {
2225                 # Only 'createaccount' can be performed on special pages,
2226                 # which don't actually exist in the DB.
2227                 if ( $this->isSpecialPage() && $action !== 'createaccount' ) {
2228                         $errors[] = [ 'ns-specialprotected' ];
2229                 }
2230
2231                 # Check $wgNamespaceProtection for restricted namespaces
2232                 if ( $this->isNamespaceProtected( $user ) ) {
2233                         $ns = $this->mNamespace == NS_MAIN ?
2234                                 wfMessage( 'nstab-main' )->text() : $this->getNsText();
2235                         $errors[] = $this->mNamespace == NS_MEDIAWIKI ?
2236                                 [ 'protectedinterface', $action ] : [ 'namespaceprotected', $ns, $action ];
2237                 }
2238
2239                 return $errors;
2240         }
2241
2242         /**
2243          * Check CSS/JS sub-page permissions
2244          *
2245          * @param string $action The action to check
2246          * @param User $user User to check
2247          * @param array $errors List of current errors
2248          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2249          * @param bool $short Short circuit on first error
2250          *
2251          * @return array List of errors
2252          */
2253         private function checkCSSandJSPermissions( $action, $user, $errors, $rigor, $short ) {
2254                 # Protect css/js subpages of user pages
2255                 # XXX: this might be better using restrictions
2256                 if ( $action != 'patrol' ) {
2257                         if ( preg_match( '/^' . preg_quote( $user->getName(), '/' ) . '\//', $this->mTextform ) ) {
2258                                 if ( $this->isCssSubpage() && !$user->isAllowedAny( 'editmyusercss', 'editusercss' ) ) {
2259                                         $errors[] = [ 'mycustomcssprotected', $action ];
2260                                 } elseif ( $this->isJsSubpage() && !$user->isAllowedAny( 'editmyuserjs', 'edituserjs' ) ) {
2261                                         $errors[] = [ 'mycustomjsprotected', $action ];
2262                                 }
2263                         } else {
2264                                 if ( $this->isCssSubpage() && !$user->isAllowed( 'editusercss' ) ) {
2265                                         $errors[] = [ 'customcssprotected', $action ];
2266                                 } elseif ( $this->isJsSubpage() && !$user->isAllowed( 'edituserjs' ) ) {
2267                                         $errors[] = [ 'customjsprotected', $action ];
2268                                 }
2269                         }
2270                 }
2271
2272                 return $errors;
2273         }
2274
2275         /**
2276          * Check against page_restrictions table requirements on this
2277          * page. The user must possess all required rights for this
2278          * action.
2279          *
2280          * @param string $action The action to check
2281          * @param User $user User to check
2282          * @param array $errors List of current errors
2283          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2284          * @param bool $short Short circuit on first error
2285          *
2286          * @return array List of errors
2287          */
2288         private function checkPageRestrictions( $action, $user, $errors, $rigor, $short ) {
2289                 foreach ( $this->getRestrictions( $action ) as $right ) {
2290                         // Backwards compatibility, rewrite sysop -> editprotected
2291                         if ( $right == 'sysop' ) {
2292                                 $right = 'editprotected';
2293                         }
2294                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2295                         if ( $right == 'autoconfirmed' ) {
2296                                 $right = 'editsemiprotected';
2297                         }
2298                         if ( $right == '' ) {
2299                                 continue;
2300                         }
2301                         if ( !$user->isAllowed( $right ) ) {
2302                                 $errors[] = [ 'protectedpagetext', $right, $action ];
2303                         } elseif ( $this->mCascadeRestriction && !$user->isAllowed( 'protect' ) ) {
2304                                 $errors[] = [ 'protectedpagetext', 'protect', $action ];
2305                         }
2306                 }
2307
2308                 return $errors;
2309         }
2310
2311         /**
2312          * Check restrictions on cascading pages.
2313          *
2314          * @param string $action The action to check
2315          * @param User $user User to check
2316          * @param array $errors List of current errors
2317          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2318          * @param bool $short Short circuit on first error
2319          *
2320          * @return array List of errors
2321          */
2322         private function checkCascadingSourcesRestrictions( $action, $user, $errors, $rigor, $short ) {
2323                 if ( $rigor !== 'quick' && !$this->isCssJsSubpage() ) {
2324                         # We /could/ use the protection level on the source page, but it's
2325                         # fairly ugly as we have to establish a precedence hierarchy for pages
2326                         # included by multiple cascade-protected pages. So just restrict
2327                         # it to people with 'protect' permission, as they could remove the
2328                         # protection anyway.
2329                         list( $cascadingSources, $restrictions ) = $this->getCascadeProtectionSources();
2330                         # Cascading protection depends on more than this page...
2331                         # Several cascading protected pages may include this page...
2332                         # Check each cascading level
2333                         # This is only for protection restrictions, not for all actions
2334                         if ( isset( $restrictions[$action] ) ) {
2335                                 foreach ( $restrictions[$action] as $right ) {
2336                                         // Backwards compatibility, rewrite sysop -> editprotected
2337                                         if ( $right == 'sysop' ) {
2338                                                 $right = 'editprotected';
2339                                         }
2340                                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2341                                         if ( $right == 'autoconfirmed' ) {
2342                                                 $right = 'editsemiprotected';
2343                                         }
2344                                         if ( $right != '' && !$user->isAllowedAll( 'protect', $right ) ) {
2345                                                 $pages = '';
2346                                                 foreach ( $cascadingSources as $page ) {
2347                                                         $pages .= '* [[:' . $page->getPrefixedText() . "]]\n";
2348                                                 }
2349                                                 $errors[] = [ 'cascadeprotected', count( $cascadingSources ), $pages, $action ];
2350                                         }
2351                                 }
2352                         }
2353                 }
2354
2355                 return $errors;
2356         }
2357
2358         /**
2359          * Check action permissions not already checked in checkQuickPermissions
2360          *
2361          * @param string $action The action to check
2362          * @param User $user User to check
2363          * @param array $errors List of current errors
2364          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2365          * @param bool $short Short circuit on first error
2366          *
2367          * @return array List of errors
2368          */
2369         private function checkActionPermissions( $action, $user, $errors, $rigor, $short ) {
2370                 global $wgDeleteRevisionsLimit, $wgLang;
2371
2372                 if ( $action == 'protect' ) {
2373                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit', $user, $rigor, true ) ) ) {
2374                                 // If they can't edit, they shouldn't protect.
2375                                 $errors[] = [ 'protect-cantedit' ];
2376                         }
2377                 } elseif ( $action == 'create' ) {
2378                         $title_protection = $this->getTitleProtection();
2379                         if ( $title_protection ) {
2380                                 if ( $title_protection['permission'] == ''
2381                                         || !$user->isAllowed( $title_protection['permission'] )
2382                                 ) {
2383                                         $errors[] = [
2384                                                 'titleprotected',
2385                                                 User::whoIs( $title_protection['user'] ),
2386                                                 $title_protection['reason']
2387                                         ];
2388                                 }
2389                         }
2390                 } elseif ( $action == 'move' ) {
2391                         // Check for immobile pages
2392                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2393                                 // Specific message for this case
2394                                 $errors[] = [ 'immobile-source-namespace', $this->getNsText() ];
2395                         } elseif ( !$this->isMovable() ) {
2396                                 // Less specific message for rarer cases
2397                                 $errors[] = [ 'immobile-source-page' ];
2398                         }
2399                 } elseif ( $action == 'move-target' ) {
2400                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2401                                 $errors[] = [ 'immobile-target-namespace', $this->getNsText() ];
2402                         } elseif ( !$this->isMovable() ) {
2403                                 $errors[] = [ 'immobile-target-page' ];
2404                         }
2405                 } elseif ( $action == 'delete' ) {
2406                         $tempErrors = $this->checkPageRestrictions( 'edit', $user, [], $rigor, true );
2407                         if ( !$tempErrors ) {
2408                                 $tempErrors = $this->checkCascadingSourcesRestrictions( 'edit',
2409                                         $user, $tempErrors, $rigor, true );
2410                         }
2411                         if ( $tempErrors ) {
2412                                 // If protection keeps them from editing, they shouldn't be able to delete.
2413                                 $errors[] = [ 'deleteprotected' ];
2414                         }
2415                         if ( $rigor !== 'quick' && $wgDeleteRevisionsLimit
2416                                 && !$this->userCan( 'bigdelete', $user ) && $this->isBigDeletion()
2417                         ) {
2418                                 $errors[] = [ 'delete-toobig', $wgLang->formatNum( $wgDeleteRevisionsLimit ) ];
2419                         }
2420                 } elseif ( $action === 'undelete' ) {
2421                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit', $user, $rigor, true ) ) ) {
2422                                 // Undeleting implies editing
2423                                 $errors[] = [ 'undelete-cantedit' ];
2424                         }
2425                         if ( !$this->exists()
2426                                 && count( $this->getUserPermissionsErrorsInternal( 'create', $user, $rigor, true ) )
2427                         ) {
2428                                 // Undeleting where nothing currently exists implies creating
2429                                 $errors[] = [ 'undelete-cantcreate' ];
2430                         }
2431                 }
2432                 return $errors;
2433         }
2434
2435         /**
2436          * Check that the user isn't blocked from editing.
2437          *
2438          * @param string $action The action to check
2439          * @param User $user User to check
2440          * @param array $errors List of current errors
2441          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2442          * @param bool $short Short circuit on first error
2443          *
2444          * @return array List of errors
2445          */
2446         private function checkUserBlock( $action, $user, $errors, $rigor, $short ) {
2447                 global $wgEmailConfirmToEdit, $wgBlockDisablesLogin;
2448                 // Account creation blocks handled at userlogin.
2449                 // Unblocking handled in SpecialUnblock
2450                 if ( $rigor === 'quick' || in_array( $action, [ 'createaccount', 'unblock' ] ) ) {
2451                         return $errors;
2452                 }
2453
2454                 // Optimize for a very common case
2455                 if ( $action === 'read' && !$wgBlockDisablesLogin ) {
2456                         return $errors;
2457                 }
2458
2459                 if ( $wgEmailConfirmToEdit && !$user->isEmailConfirmed() ) {
2460                         $errors[] = [ 'confirmedittext' ];
2461                 }
2462
2463                 $useSlave = ( $rigor !== 'secure' );
2464                 if ( ( $action == 'edit' || $action == 'create' )
2465                         && !$user->isBlockedFrom( $this, $useSlave )
2466                 ) {
2467                         // Don't block the user from editing their own talk page unless they've been
2468                         // explicitly blocked from that too.
2469                 } elseif ( $user->isBlocked() && $user->getBlock()->prevents( $action ) !== false ) {
2470                         // @todo FIXME: Pass the relevant context into this function.
2471                         $errors[] = $user->getBlock()->getPermissionsError( RequestContext::getMain() );
2472                 }
2473
2474                 return $errors;
2475         }
2476
2477         /**
2478          * Check that the user is allowed to read this page.
2479          *
2480          * @param string $action The action to check
2481          * @param User $user User to check
2482          * @param array $errors List of current errors
2483          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2484          * @param bool $short Short circuit on first error
2485          *
2486          * @return array List of errors
2487          */
2488         private function checkReadPermissions( $action, $user, $errors, $rigor, $short ) {
2489                 global $wgWhitelistRead, $wgWhitelistReadRegexp;
2490
2491                 $whitelisted = false;
2492                 if ( User::isEveryoneAllowed( 'read' ) ) {
2493                         # Shortcut for public wikis, allows skipping quite a bit of code
2494                         $whitelisted = true;
2495                 } elseif ( $user->isAllowed( 'read' ) ) {
2496                         # If the user is allowed to read pages, he is allowed to read all pages
2497                         $whitelisted = true;
2498                 } elseif ( $this->isSpecial( 'Userlogin' )
2499                         || $this->isSpecial( 'PasswordReset' )
2500                         || $this->isSpecial( 'Userlogout' )
2501                 ) {
2502                         # Always grant access to the login page.
2503                         # Even anons need to be able to log in.
2504                         $whitelisted = true;
2505                 } elseif ( is_array( $wgWhitelistRead ) && count( $wgWhitelistRead ) ) {
2506                         # Time to check the whitelist
2507                         # Only do these checks is there's something to check against
2508                         $name = $this->getPrefixedText();
2509                         $dbName = $this->getPrefixedDBkey();
2510
2511                         // Check for explicit whitelisting with and without underscores
2512                         if ( in_array( $name, $wgWhitelistRead, true ) || in_array( $dbName, $wgWhitelistRead, true ) ) {
2513                                 $whitelisted = true;
2514                         } elseif ( $this->getNamespace() == NS_MAIN ) {
2515                                 # Old settings might have the title prefixed with
2516                                 # a colon for main-namespace pages
2517                                 if ( in_array( ':' . $name, $wgWhitelistRead ) ) {
2518                                         $whitelisted = true;
2519                                 }
2520                         } elseif ( $this->isSpecialPage() ) {
2521                                 # If it's a special page, ditch the subpage bit and check again
2522                                 $name = $this->getDBkey();
2523                                 list( $name, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $name );
2524                                 if ( $name ) {
2525                                         $pure = SpecialPage::getTitleFor( $name )->getPrefixedText();
2526                                         if ( in_array( $pure, $wgWhitelistRead, true ) ) {
2527                                                 $whitelisted = true;
2528                                         }
2529                                 }
2530                         }
2531                 }
2532
2533                 if ( !$whitelisted && is_array( $wgWhitelistReadRegexp ) && !empty( $wgWhitelistReadRegexp ) ) {
2534                         $name = $this->getPrefixedText();
2535                         // Check for regex whitelisting
2536                         foreach ( $wgWhitelistReadRegexp as $listItem ) {
2537                                 if ( preg_match( $listItem, $name ) ) {
2538                                         $whitelisted = true;
2539                                         break;
2540                                 }
2541                         }
2542                 }
2543
2544                 if ( !$whitelisted ) {
2545                         # If the title is not whitelisted, give extensions a chance to do so...
2546                         Hooks::run( 'TitleReadWhitelist', [ $this, $user, &$whitelisted ] );
2547                         if ( !$whitelisted ) {
2548                                 $errors[] = $this->missingPermissionError( $action, $short );
2549                         }
2550                 }
2551
2552                 return $errors;
2553         }
2554
2555         /**
2556          * Get a description array when the user doesn't have the right to perform
2557          * $action (i.e. when User::isAllowed() returns false)
2558          *
2559          * @param string $action The action to check
2560          * @param bool $short Short circuit on first error
2561          * @return array Array containing an error message key and any parameters
2562          */
2563         private function missingPermissionError( $action, $short ) {
2564                 // We avoid expensive display logic for quickUserCan's and such
2565                 if ( $short ) {
2566                         return [ 'badaccess-group0' ];
2567                 }
2568
2569                 return User::newFatalPermissionDeniedStatus( $action )->getErrorsArray()[0];
2570         }
2571
2572         /**
2573          * Can $user perform $action on this page? This is an internal function,
2574          * with multiple levels of checks depending on performance needs; see $rigor below.
2575          * It does not check wfReadOnly().
2576          *
2577          * @param string $action Action that permission needs to be checked for
2578          * @param User $user User to check
2579          * @param string $rigor One of (quick,full,secure)
2580          *   - quick  : does cheap permission checks from replica DBs (usable for GUI creation)
2581          *   - full   : does cheap and expensive checks possibly from a replica DB
2582          *   - secure : does cheap and expensive checks, using the master as needed
2583          * @param bool $short Set this to true to stop after the first permission error.
2584          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
2585          */
2586         protected function getUserPermissionsErrorsInternal(
2587                 $action, $user, $rigor = 'secure', $short = false
2588         ) {
2589                 if ( $rigor === true ) {
2590                         $rigor = 'secure'; // b/c
2591                 } elseif ( $rigor === false ) {
2592                         $rigor = 'quick'; // b/c
2593                 } elseif ( !in_array( $rigor, [ 'quick', 'full', 'secure' ] ) ) {
2594                         throw new Exception( "Invalid rigor parameter '$rigor'." );
2595                 }
2596
2597                 # Read has special handling
2598                 if ( $action == 'read' ) {
2599                         $checks = [
2600                                 'checkPermissionHooks',
2601                                 'checkReadPermissions',
2602                                 'checkUserBlock', // for wgBlockDisablesLogin
2603                         ];
2604                 # Don't call checkSpecialsAndNSPermissions or checkCSSandJSPermissions
2605                 # here as it will lead to duplicate error messages. This is okay to do
2606                 # since anywhere that checks for create will also check for edit, and
2607                 # those checks are called for edit.
2608                 } elseif ( $action == 'create' ) {
2609                         $checks = [
2610                                 'checkQuickPermissions',
2611                                 'checkPermissionHooks',
2612                                 'checkPageRestrictions',
2613                                 'checkCascadingSourcesRestrictions',
2614                                 'checkActionPermissions',
2615                                 'checkUserBlock'
2616                         ];
2617                 } else {
2618                         $checks = [
2619                                 'checkQuickPermissions',
2620                                 'checkPermissionHooks',
2621                                 'checkSpecialsAndNSPermissions',
2622                                 'checkCSSandJSPermissions',
2623                                 'checkPageRestrictions',
2624                                 'checkCascadingSourcesRestrictions',
2625                                 'checkActionPermissions',
2626                                 'checkUserBlock'
2627                         ];
2628                 }
2629
2630                 $errors = [];
2631                 while ( count( $checks ) > 0 &&
2632                                 !( $short && count( $errors ) > 0 ) ) {
2633                         $method = array_shift( $checks );
2634                         $errors = $this->$method( $action, $user, $errors, $rigor, $short );
2635                 }
2636
2637                 return $errors;
2638         }
2639
2640         /**
2641          * Get a filtered list of all restriction types supported by this wiki.
2642          * @param bool $exists True to get all restriction types that apply to
2643          * titles that do exist, False for all restriction types that apply to
2644          * titles that do not exist
2645          * @return array
2646          */
2647         public static function getFilteredRestrictionTypes( $exists = true ) {
2648                 global $wgRestrictionTypes;
2649                 $types = $wgRestrictionTypes;
2650                 if ( $exists ) {
2651                         # Remove the create restriction for existing titles
2652                         $types = array_diff( $types, [ 'create' ] );
2653                 } else {
2654                         # Only the create and upload restrictions apply to non-existing titles
2655                         $types = array_intersect( $types, [ 'create', 'upload' ] );
2656                 }
2657                 return $types;
2658         }
2659
2660         /**
2661          * Returns restriction types for the current Title
2662          *
2663          * @return array Applicable restriction types
2664          */
2665         public function getRestrictionTypes() {
2666                 if ( $this->isSpecialPage() ) {
2667                         return [];
2668                 }
2669
2670                 $types = self::getFilteredRestrictionTypes( $this->exists() );
2671
2672                 if ( $this->getNamespace() != NS_FILE ) {
2673                         # Remove the upload restriction for non-file titles
2674                         $types = array_diff( $types, [ 'upload' ] );
2675                 }
2676
2677                 Hooks::run( 'TitleGetRestrictionTypes', [ $this, &$types ] );
2678
2679                 wfDebug( __METHOD__ . ': applicable restrictions to [[' .
2680                         $this->getPrefixedText() . ']] are {' . implode( ',', $types ) . "}\n" );
2681
2682                 return $types;
2683         }
2684
2685         /**
2686          * Is this title subject to title protection?
2687          * Title protection is the one applied against creation of such title.
2688          *
2689          * @return array|bool An associative array representing any existent title
2690          *   protection, or false if there's none.
2691          */
2692         public function getTitleProtection() {
2693                 $protection = $this->getTitleProtectionInternal();
2694                 if ( $protection ) {
2695                         if ( $protection['permission'] == 'sysop' ) {
2696                                 $protection['permission'] = 'editprotected'; // B/C
2697                         }
2698                         if ( $protection['permission'] == 'autoconfirmed' ) {
2699                                 $protection['permission'] = 'editsemiprotected'; // B/C
2700                         }
2701                 }
2702                 return $protection;
2703         }
2704
2705         /**
2706          * Fetch title protection settings
2707          *
2708          * To work correctly, $this->loadRestrictions() needs to have access to the
2709          * actual protections in the database without munging 'sysop' =>
2710          * 'editprotected' and 'autoconfirmed' => 'editsemiprotected'. Other
2711          * callers probably want $this->getTitleProtection() instead.
2712          *
2713          * @return array|bool
2714          */
2715         protected function getTitleProtectionInternal() {
2716                 // Can't protect pages in special namespaces
2717                 if ( $this->getNamespace() < 0 ) {
2718                         return false;
2719                 }
2720
2721                 // Can't protect pages that exist.
2722                 if ( $this->exists() ) {
2723                         return false;
2724                 }
2725
2726                 if ( $this->mTitleProtection === null ) {
2727                         $dbr = wfGetDB( DB_REPLICA );
2728                         $commentStore = new CommentStore( 'pt_reason' );
2729                         $commentQuery = $commentStore->getJoin();
2730                         $res = $dbr->select(
2731                                 [ 'protected_titles' ] + $commentQuery['tables'],
2732                                 [
2733                                         'user' => 'pt_user',
2734                                         'expiry' => 'pt_expiry',
2735                                         'permission' => 'pt_create_perm'
2736                                 ] + $commentQuery['fields'],
2737                                 [ 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ],
2738                                 __METHOD__,
2739                                 [],
2740                                 $commentQuery['joins']
2741                         );
2742
2743                         // fetchRow returns false if there are no rows.
2744                         $row = $dbr->fetchRow( $res );
2745                         if ( $row ) {
2746                                 $this->mTitleProtection = [
2747                                         'user' => $row['user'],
2748                                         'expiry' => $dbr->decodeExpiry( $row['expiry'] ),
2749                                         'permission' => $row['permission'],
2750                                         'reason' => $commentStore->getComment( $row )->text,
2751                                 ];
2752                         } else {
2753                                 $this->mTitleProtection = false;
2754                         }
2755                 }
2756                 return $this->mTitleProtection;
2757         }
2758
2759         /**
2760          * Remove any title protection due to page existing
2761          */
2762         public function deleteTitleProtection() {
2763                 $dbw = wfGetDB( DB_MASTER );
2764
2765                 $dbw->delete(
2766                         'protected_titles',
2767                         [ 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ],
2768                         __METHOD__
2769                 );
2770                 $this->mTitleProtection = false;
2771         }
2772
2773         /**
2774          * Is this page "semi-protected" - the *only* protection levels are listed
2775          * in $wgSemiprotectedRestrictionLevels?
2776          *
2777          * @param string $action Action to check (default: edit)
2778          * @return bool
2779          */
2780         public function isSemiProtected( $action = 'edit' ) {
2781                 global $wgSemiprotectedRestrictionLevels;
2782
2783                 $restrictions = $this->getRestrictions( $action );
2784                 $semi = $wgSemiprotectedRestrictionLevels;
2785                 if ( !$restrictions || !$semi ) {
2786                         // Not protected, or all protection is full protection
2787                         return false;
2788                 }
2789
2790                 // Remap autoconfirmed to editsemiprotected for BC
2791                 foreach ( array_keys( $semi, 'autoconfirmed' ) as $key ) {
2792                         $semi[$key] = 'editsemiprotected';
2793                 }
2794                 foreach ( array_keys( $restrictions, 'autoconfirmed' ) as $key ) {
2795                         $restrictions[$key] = 'editsemiprotected';
2796                 }
2797
2798                 return !array_diff( $restrictions, $semi );
2799         }
2800
2801         /**
2802          * Does the title correspond to a protected article?
2803          *
2804          * @param string $action The action the page is protected from,
2805          * by default checks all actions.
2806          * @return bool
2807          */
2808         public function isProtected( $action = '' ) {
2809                 global $wgRestrictionLevels;
2810
2811                 $restrictionTypes = $this->getRestrictionTypes();
2812
2813                 # Special pages have inherent protection
2814                 if ( $this->isSpecialPage() ) {
2815                         return true;
2816                 }
2817
2818                 # Check regular protection levels
2819                 foreach ( $restrictionTypes as $type ) {
2820                         if ( $action == $type || $action == '' ) {
2821                                 $r = $this->getRestrictions( $type );
2822                                 foreach ( $wgRestrictionLevels as $level ) {
2823                                         if ( in_array( $level, $r ) && $level != '' ) {
2824                                                 return true;
2825                                         }
2826                                 }
2827                         }
2828                 }
2829
2830                 return false;
2831         }
2832
2833         /**
2834          * Determines if $user is unable to edit this page because it has been protected
2835          * by $wgNamespaceProtection.
2836          *
2837          * @param User $user User object to check permissions
2838          * @return bool
2839          */
2840         public function isNamespaceProtected( User $user ) {
2841                 global $wgNamespaceProtection;
2842
2843                 if ( isset( $wgNamespaceProtection[$this->mNamespace] ) ) {
2844                         foreach ( (array)$wgNamespaceProtection[$this->mNamespace] as $right ) {
2845                                 if ( $right != '' && !$user->isAllowed( $right ) ) {
2846                                         return true;
2847                                 }
2848                         }
2849                 }
2850                 return false;
2851         }
2852
2853         /**
2854          * Cascading protection: Return true if cascading restrictions apply to this page, false if not.
2855          *
2856          * @return bool If the page is subject to cascading restrictions.
2857          */
2858         public function isCascadeProtected() {
2859                 list( $sources, /* $restrictions */ ) = $this->getCascadeProtectionSources( false );
2860                 return ( $sources > 0 );
2861         }
2862
2863         /**
2864          * Determines whether cascading protection sources have already been loaded from
2865          * the database.
2866          *
2867          * @param bool $getPages True to check if the pages are loaded, or false to check
2868          * if the status is loaded.
2869          * @return bool Whether or not the specified information has been loaded
2870          * @since 1.23
2871          */
2872         public function areCascadeProtectionSourcesLoaded( $getPages = true ) {
2873                 return $getPages ? $this->mCascadeSources !== null : $this->mHasCascadingRestrictions !== null;
2874         }
2875
2876         /**
2877          * Cascading protection: Get the source of any cascading restrictions on this page.
2878          *
2879          * @param bool $getPages Whether or not to retrieve the actual pages
2880          *        that the restrictions have come from and the actual restrictions
2881          *        themselves.
2882          * @return array Two elements: First is an array of Title objects of the
2883          *        pages from which cascading restrictions have come, false for
2884          *        none, or true if such restrictions exist but $getPages was not
2885          *        set. Second is an array like that returned by
2886          *        Title::getAllRestrictions(), or an empty array if $getPages is
2887          *        false.
2888          */
2889         public function getCascadeProtectionSources( $getPages = true ) {
2890                 $pagerestrictions = [];
2891
2892                 if ( $this->mCascadeSources !== null && $getPages ) {
2893                         return [ $this->mCascadeSources, $this->mCascadingRestrictions ];
2894                 } elseif ( $this->mHasCascadingRestrictions !== null && !$getPages ) {
2895                         return [ $this->mHasCascadingRestrictions, $pagerestrictions ];
2896                 }
2897
2898                 $dbr = wfGetDB( DB_REPLICA );
2899
2900                 if ( $this->getNamespace() == NS_FILE ) {
2901                         $tables = [ 'imagelinks', 'page_restrictions' ];
2902                         $where_clauses = [
2903                                 'il_to' => $this->getDBkey(),
2904                                 'il_from=pr_page',
2905                                 'pr_cascade' => 1
2906                         ];
2907                 } else {
2908                         $tables = [ 'templatelinks', 'page_restrictions' ];
2909                         $where_clauses = [
2910                                 'tl_namespace' => $this->getNamespace(),
2911                                 'tl_title' => $this->getDBkey(),
2912                                 'tl_from=pr_page',
2913                                 'pr_cascade' => 1
2914                         ];
2915                 }
2916
2917                 if ( $getPages ) {
2918                         $cols = [ 'pr_page', 'page_namespace', 'page_title',
2919                                 'pr_expiry', 'pr_type', 'pr_level' ];
2920                         $where_clauses[] = 'page_id=pr_page';
2921                         $tables[] = 'page';
2922                 } else {
2923                         $cols = [ 'pr_expiry' ];
2924                 }
2925
2926                 $res = $dbr->select( $tables, $cols, $where_clauses, __METHOD__ );
2927
2928                 $sources = $getPages ? [] : false;
2929                 $now = wfTimestampNow();
2930
2931                 foreach ( $res as $row ) {
2932                         $expiry = $dbr->decodeExpiry( $row->pr_expiry );
2933                         if ( $expiry > $now ) {
2934                                 if ( $getPages ) {
2935                                         $page_id = $row->pr_page;
2936                                         $page_ns = $row->page_namespace;
2937                                         $page_title = $row->page_title;
2938                                         $sources[$page_id] = self::makeTitle( $page_ns, $page_title );
2939                                         # Add groups needed for each restriction type if its not already there
2940                                         # Make sure this restriction type still exists
2941
2942                                         if ( !isset( $pagerestrictions[$row->pr_type] ) ) {
2943                                                 $pagerestrictions[$row->pr_type] = [];
2944                                         }
2945
2946                                         if (
2947                                                 isset( $pagerestrictions[$row->pr_type] )
2948                                                 && !in_array( $row->pr_level, $pagerestrictions[$row->pr_type] )
2949                                         ) {
2950                                                 $pagerestrictions[$row->pr_type][] = $row->pr_level;
2951                                         }
2952                                 } else {
2953                                         $sources = true;
2954                                 }
2955                         }
2956                 }
2957
2958                 if ( $getPages ) {
2959                         $this->mCascadeSources = $sources;
2960                         $this->mCascadingRestrictions = $pagerestrictions;
2961                 } else {
2962                         $this->mHasCascadingRestrictions = $sources;
2963                 }
2964
2965                 return [ $sources, $pagerestrictions ];
2966         }
2967
2968         /**
2969          * Accessor for mRestrictionsLoaded
2970          *
2971          * @return bool Whether or not the page's restrictions have already been
2972          * loaded from the database
2973          * @since 1.23
2974          */
2975         public function areRestrictionsLoaded() {
2976                 return $this->mRestrictionsLoaded;
2977         }
2978
2979         /**
2980          * Accessor/initialisation for mRestrictions
2981          *
2982          * @param string $action Action that permission needs to be checked for
2983          * @return array Restriction levels needed to take the action. All levels are
2984          *     required. Note that restriction levels are normally user rights, but 'sysop'
2985          *     and 'autoconfirmed' are also allowed for backwards compatibility. These should
2986          *     be mapped to 'editprotected' and 'editsemiprotected' respectively.
2987          */
2988         public function getRestrictions( $action ) {
2989                 if ( !$this->mRestrictionsLoaded ) {
2990                         $this->loadRestrictions();
2991                 }
2992                 return isset( $this->mRestrictions[$action] )
2993                                 ? $this->mRestrictions[$action]
2994                                 : [];
2995         }
2996
2997         /**
2998          * Accessor/initialisation for mRestrictions
2999          *
3000          * @return array Keys are actions, values are arrays as returned by
3001          *     Title::getRestrictions()
3002          * @since 1.23
3003          */
3004         public function getAllRestrictions() {
3005                 if ( !$this->mRestrictionsLoaded ) {
3006                         $this->loadRestrictions();
3007                 }
3008                 return $this->mRestrictions;
3009         }
3010
3011         /**
3012          * Get the expiry time for the restriction against a given action
3013          *
3014          * @param string $action
3015          * @return string|bool 14-char timestamp, or 'infinity' if the page is protected forever
3016          *     or not protected at all, or false if the action is not recognised.
3017          */
3018         public function getRestrictionExpiry( $action ) {
3019                 if ( !$this->mRestrictionsLoaded ) {
3020                         $this->loadRestrictions();
3021                 }
3022                 return isset( $this->mRestrictionsExpiry[$action] ) ? $this->mRestrictionsExpiry[$action] : false;
3023         }
3024
3025         /**
3026          * Returns cascading restrictions for the current article
3027          *
3028          * @return bool
3029          */
3030         function areRestrictionsCascading() {
3031                 if ( !$this->mRestrictionsLoaded ) {
3032                         $this->loadRestrictions();
3033                 }
3034
3035                 return $this->mCascadeRestriction;
3036         }
3037
3038         /**
3039          * Compiles list of active page restrictions from both page table (pre 1.10)
3040          * and page_restrictions table for this existing page.
3041          * Public for usage by LiquidThreads.
3042          *
3043          * @param array $rows Array of db result objects
3044          * @param string $oldFashionedRestrictions Comma-separated list of page
3045          *   restrictions from page table (pre 1.10)
3046          */
3047         public function loadRestrictionsFromRows( $rows, $oldFashionedRestrictions = null ) {
3048                 $dbr = wfGetDB( DB_REPLICA );
3049
3050                 $restrictionTypes = $this->getRestrictionTypes();
3051
3052                 foreach ( $restrictionTypes as $type ) {
3053                         $this->mRestrictions[$type] = [];
3054                         $this->mRestrictionsExpiry[$type] = 'infinity';
3055                 }
3056
3057                 $this->mCascadeRestriction = false;
3058
3059                 # Backwards-compatibility: also load the restrictions from the page record (old format).
3060                 if ( $oldFashionedRestrictions !== null ) {
3061                         $this->mOldRestrictions = $oldFashionedRestrictions;
3062                 }
3063
3064                 if ( $this->mOldRestrictions === false ) {
3065                         $this->mOldRestrictions = $dbr->selectField( 'page', 'page_restrictions',
3066                                 [ 'page_id' => $this->getArticleID() ], __METHOD__ );
3067                 }
3068
3069                 if ( $this->mOldRestrictions != '' ) {
3070                         foreach ( explode( ':', trim( $this->mOldRestrictions ) ) as $restrict ) {
3071                                 $temp = explode( '=', trim( $restrict ) );
3072                                 if ( count( $temp ) == 1 ) {
3073                                         // old old format should be treated as edit/move restriction
3074                                         $this->mRestrictions['edit'] = explode( ',', trim( $temp[0] ) );
3075                                         $this->mRestrictions['move'] = explode( ',', trim( $temp[0] ) );
3076                                 } else {
3077                                         $restriction = trim( $temp[1] );
3078                                         if ( $restriction != '' ) { // some old entries are empty
3079                                                 $this->mRestrictions[$temp[0]] = explode( ',', $restriction );
3080                                         }
3081                                 }
3082                         }
3083                 }
3084
3085                 if ( count( $rows ) ) {
3086                         # Current system - load second to make them override.
3087                         $now = wfTimestampNow();
3088
3089                         # Cycle through all the restrictions.
3090                         foreach ( $rows as $row ) {
3091                                 // Don't take care of restrictions types that aren't allowed
3092                                 if ( !in_array( $row->pr_type, $restrictionTypes ) ) {
3093                                         continue;
3094                                 }
3095
3096                                 $expiry = $dbr->decodeExpiry( $row->pr_expiry );
3097
3098                                 // Only apply the restrictions if they haven't expired!
3099                                 if ( !$expiry || $expiry > $now ) {
3100                                         $this->mRestrictionsExpiry[$row->pr_type] = $expiry;
3101                                         $this->mRestrictions[$row->pr_type] = explode( ',', trim( $row->pr_level ) );
3102
3103                                         $this->mCascadeRestriction |= $row->pr_cascade;
3104                                 }
3105                         }
3106                 }
3107
3108                 $this->mRestrictionsLoaded = true;
3109         }
3110
3111         /**
3112          * Load restrictions from the page_restrictions table
3113          *
3114          * @param string $oldFashionedRestrictions Comma-separated list of page
3115          *   restrictions from page table (pre 1.10)
3116          */
3117         public function loadRestrictions( $oldFashionedRestrictions = null ) {
3118                 if ( $this->mRestrictionsLoaded ) {
3119                         return;
3120                 }
3121
3122                 $id = $this->getArticleID();
3123                 if ( $id ) {
3124                         $cache = ObjectCache::getMainWANInstance();
3125                         $rows = $cache->getWithSetCallback(
3126                                 // Page protections always leave a new null revision
3127                                 $cache->makeKey( 'page-restrictions', $id, $this->getLatestRevID() ),
3128                                 $cache::TTL_DAY,
3129                                 function ( $curValue, &$ttl, array &$setOpts ) {
3130                                         $dbr = wfGetDB( DB_REPLICA );
3131
3132                                         $setOpts += Database::getCacheSetOptions( $dbr );
3133
3134                                         return iterator_to_array(
3135                                                 $dbr->select(
3136                                                         'page_restrictions',
3137                                                         [ 'pr_type', 'pr_expiry', 'pr_level', 'pr_cascade' ],
3138                                                         [ 'pr_page' => $this->getArticleID() ],
3139                                                         __METHOD__
3140                                                 )
3141                                         );
3142                                 }
3143                         );
3144
3145                         $this->loadRestrictionsFromRows( $rows, $oldFashionedRestrictions );
3146                 } else {
3147                         $title_protection = $this->getTitleProtectionInternal();
3148
3149                         if ( $title_protection ) {
3150                                 $now = wfTimestampNow();
3151                                 $expiry = wfGetDB( DB_REPLICA )->decodeExpiry( $title_protection['expiry'] );
3152
3153                                 if ( !$expiry || $expiry > $now ) {
3154                                         // Apply the restrictions
3155                                         $this->mRestrictionsExpiry['create'] = $expiry;
3156                                         $this->mRestrictions['create'] =
3157                                                 explode( ',', trim( $title_protection['permission'] ) );
3158                                 } else { // Get rid of the old restrictions
3159                                         $this->mTitleProtection = false;
3160                                 }
3161                         } else {
3162                                 $this->mRestrictionsExpiry['create'] = 'infinity';
3163                         }
3164                         $this->mRestrictionsLoaded = true;
3165                 }
3166         }
3167
3168         /**
3169          * Flush the protection cache in this object and force reload from the database.
3170          * This is used when updating protection from WikiPage::doUpdateRestrictions().
3171          */
3172         public function flushRestrictions() {
3173                 $this->mRestrictionsLoaded = false;
3174                 $this->mTitleProtection = null;
3175         }
3176
3177         /**
3178          * Purge expired restrictions from the page_restrictions table
3179          *
3180          * This will purge no more than $wgUpdateRowsPerQuery page_restrictions rows
3181          */
3182         static function purgeExpiredRestrictions() {
3183                 if ( wfReadOnly() ) {
3184                         return;
3185                 }
3186
3187                 DeferredUpdates::addUpdate( new AtomicSectionUpdate(
3188                         wfGetDB( DB_MASTER ),
3189                         __METHOD__,
3190                         function ( IDatabase $dbw, $fname ) {
3191                                 $config = MediaWikiServices::getInstance()->getMainConfig();
3192                                 $ids = $dbw->selectFieldValues(
3193                                         'page_restrictions',
3194                                         'pr_id',
3195                                         [ 'pr_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ],
3196                                         $fname,
3197                                         [ 'LIMIT' => $config->get( 'UpdateRowsPerQuery' ) ] // T135470
3198                                 );
3199                                 if ( $ids ) {
3200                                         $dbw->delete( 'page_restrictions', [ 'pr_id' => $ids ], $fname );
3201                                 }
3202                         }
3203                 ) );
3204
3205                 DeferredUpdates::addUpdate( new AtomicSectionUpdate(
3206                         wfGetDB( DB_MASTER ),
3207                         __METHOD__,
3208                         function ( IDatabase $dbw, $fname ) {
3209                                 $dbw->delete(
3210                                         'protected_titles',
3211                                         [ 'pt_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ],
3212                                         $fname
3213                                 );
3214                         }
3215                 ) );
3216         }
3217
3218         /**
3219          * Does this have subpages?  (Warning, usually requires an extra DB query.)
3220          *
3221          * @return bool
3222          */
3223         public function hasSubpages() {
3224                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
3225                         # Duh
3226                         return false;
3227                 }
3228
3229                 # We dynamically add a member variable for the purpose of this method
3230                 # alone to cache the result.  There's no point in having it hanging
3231                 # around uninitialized in every Title object; therefore we only add it
3232                 # if needed and don't declare it statically.
3233                 if ( $this->mHasSubpages === null ) {
3234                         $this->mHasSubpages = false;
3235                         $subpages = $this->getSubpages( 1 );
3236                         if ( $subpages instanceof TitleArray ) {
3237                                 $this->mHasSubpages = (bool)$subpages->count();
3238                         }
3239                 }
3240
3241                 return $this->mHasSubpages;
3242         }
3243
3244         /**
3245          * Get all subpages of this page.
3246          *
3247          * @param int $limit Maximum number of subpages to fetch; -1 for no limit
3248          * @return TitleArray|array TitleArray, or empty array if this page's namespace
3249          *  doesn't allow subpages
3250          */
3251         public function getSubpages( $limit = -1 ) {
3252                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3253                         return [];
3254                 }
3255
3256                 $dbr = wfGetDB( DB_REPLICA );
3257                 $conds['page_namespace'] = $this->getNamespace();
3258                 $conds[] = 'page_title ' . $dbr->buildLike( $this->getDBkey() . '/', $dbr->anyString() );
3259                 $options = [];
3260                 if ( $limit > -1 ) {
3261                         $options['LIMIT'] = $limit;
3262                 }
3263                 return TitleArray::newFromResult(
3264                         $dbr->select( 'page',
3265                                 [ 'page_id', 'page_namespace', 'page_title', 'page_is_redirect' ],
3266                                 $conds,
3267                                 __METHOD__,
3268                                 $options
3269                         )
3270                 );
3271         }
3272
3273         /**
3274          * Is there a version of this page in the deletion archive?
3275          *
3276          * @return int The number of archived revisions
3277          */
3278         public function isDeleted() {
3279                 if ( $this->getNamespace() < 0 ) {
3280                         $n = 0;
3281                 } else {
3282                         $dbr = wfGetDB( DB_REPLICA );
3283
3284                         $n = $dbr->selectField( 'archive', 'COUNT(*)',
3285                                 [ 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ],
3286                                 __METHOD__
3287                         );
3288                         if ( $this->getNamespace() == NS_FILE ) {
3289                                 $n += $dbr->selectField( 'filearchive', 'COUNT(*)',
3290                                         [ 'fa_name' => $this->getDBkey() ],
3291                                         __METHOD__
3292                                 );
3293                         }
3294                 }
3295                 return (int)$n;
3296         }
3297
3298         /**
3299          * Is there a version of this page in the deletion archive?
3300          *
3301          * @return bool
3302          */
3303         public function isDeletedQuick() {
3304                 if ( $this->getNamespace() < 0 ) {
3305                         return false;
3306                 }
3307                 $dbr = wfGetDB( DB_REPLICA );
3308                 $deleted = (bool)$dbr->selectField( 'archive', '1',
3309                         [ 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ],
3310                         __METHOD__
3311                 );
3312                 if ( !$deleted && $this->getNamespace() == NS_FILE ) {
3313                         $deleted = (bool)$dbr->selectField( 'filearchive', '1',
3314                                 [ 'fa_name' => $this->getDBkey() ],
3315                                 __METHOD__
3316                         );
3317                 }
3318                 return $deleted;
3319         }
3320
3321         /**
3322          * Get the article ID for this Title from the link cache,
3323          * adding it if necessary
3324          *
3325          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select
3326          *  for update
3327          * @return int The ID
3328          */
3329         public function getArticleID( $flags = 0 ) {
3330                 if ( $this->getNamespace() < 0 ) {
3331                         $this->mArticleID = 0;
3332                         return $this->mArticleID;
3333                 }
3334                 $linkCache = LinkCache::singleton();
3335                 if ( $flags & self::GAID_FOR_UPDATE ) {
3336                         $oldUpdate = $linkCache->forUpdate( true );
3337                         $linkCache->clearLink( $this );
3338                         $this->mArticleID = $linkCache->addLinkObj( $this );
3339                         $linkCache->forUpdate( $oldUpdate );
3340                 } else {
3341                         if ( -1 == $this->mArticleID ) {
3342                                 $this->mArticleID = $linkCache->addLinkObj( $this );
3343                         }
3344                 }
3345                 return $this->mArticleID;
3346         }
3347
3348         /**
3349          * Is this an article that is a redirect page?
3350          * Uses link cache, adding it if necessary
3351          *
3352          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3353          * @return bool
3354          */
3355         public function isRedirect( $flags = 0 ) {
3356                 if ( !is_null( $this->mRedirect ) ) {
3357                         return $this->mRedirect;
3358                 }
3359                 if ( !$this->getArticleID( $flags ) ) {
3360                         $this->mRedirect = false;
3361                         return $this->mRedirect;
3362                 }
3363
3364                 $linkCache = LinkCache::singleton();
3365                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3366                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'redirect' );
3367                 if ( $cached === null ) {
3368                         # Trust LinkCache's state over our own
3369                         # LinkCache is telling us that the page doesn't exist, despite there being cached
3370                         # data relating to an existing page in $this->mArticleID. Updaters should clear
3371                         # LinkCache as appropriate, or use $flags = Title::GAID_FOR_UPDATE. If that flag is
3372                         # set, then LinkCache will definitely be up to date here, since getArticleID() forces
3373                         # LinkCache to refresh its data from the master.
3374                         $this->mRedirect = false;
3375                         return $this->mRedirect;
3376                 }
3377
3378                 $this->mRedirect = (bool)$cached;
3379
3380                 return $this->mRedirect;
3381         }
3382
3383         /**
3384          * What is the length of this page?
3385          * Uses link cache, adding it if necessary
3386          *
3387          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3388          * @return int
3389          */
3390         public function getLength( $flags = 0 ) {
3391                 if ( $this->mLength != -1 ) {
3392                         return $this->mLength;
3393                 }
3394                 if ( !$this->getArticleID( $flags ) ) {
3395                         $this->mLength = 0;
3396                         return $this->mLength;
3397                 }
3398                 $linkCache = LinkCache::singleton();
3399                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3400                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'length' );
3401                 if ( $cached === null ) {
3402                         # Trust LinkCache's state over our own, as for isRedirect()
3403                         $this->mLength = 0;
3404                         return $this->mLength;
3405                 }
3406
3407                 $this->mLength = intval( $cached );
3408
3409                 return $this->mLength;
3410         }
3411
3412         /**
3413          * What is the page_latest field for this page?
3414          *
3415          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3416          * @return int Int or 0 if the page doesn't exist
3417          */
3418         public function getLatestRevID( $flags = 0 ) {
3419                 if ( !( $flags & self::GAID_FOR_UPDATE ) && $this->mLatestID !== false ) {
3420                         return intval( $this->mLatestID );
3421                 }
3422                 if ( !$this->getArticleID( $flags ) ) {
3423                         $this->mLatestID = 0;
3424                         return $this->mLatestID;
3425                 }
3426                 $linkCache = LinkCache::singleton();
3427                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3428                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'revision' );
3429                 if ( $cached === null ) {
3430                         # Trust LinkCache's state over our own, as for isRedirect()
3431                         $this->mLatestID = 0;
3432                         return $this->mLatestID;
3433                 }
3434
3435                 $this->mLatestID = intval( $cached );
3436
3437                 return $this->mLatestID;
3438         }
3439
3440         /**
3441          * This clears some fields in this object, and clears any associated
3442          * keys in the "bad links" section of the link cache.
3443          *
3444          * - This is called from WikiPage::doEditContent() and WikiPage::insertOn() to allow
3445          * loading of the new page_id. It's also called from
3446          * WikiPage::doDeleteArticleReal()
3447          *
3448          * @param int $newid The new Article ID
3449          */
3450         public function resetArticleID( $newid ) {
3451                 $linkCache = LinkCache::singleton();
3452                 $linkCache->clearLink( $this );
3453
3454                 if ( $newid === false ) {
3455                         $this->mArticleID = -1;
3456                 } else {
3457                         $this->mArticleID = intval( $newid );
3458                 }
3459                 $this->mRestrictionsLoaded = false;
3460                 $this->mRestrictions = [];
3461                 $this->mOldRestrictions = false;
3462                 $this->mRedirect = null;
3463                 $this->mLength = -1;
3464                 $this->mLatestID = false;
3465                 $this->mContentModel = false;
3466                 $this->mEstimateRevisions = null;
3467                 $this->mPageLanguage = false;
3468                 $this->mDbPageLanguage = false;
3469                 $this->mIsBigDeletion = null;
3470         }
3471
3472         public static function clearCaches() {
3473                 $linkCache = LinkCache::singleton();
3474                 $linkCache->clear();
3475
3476                 $titleCache = self::getTitleCache();
3477                 $titleCache->clear();
3478         }
3479
3480         /**
3481          * Capitalize a text string for a title if it belongs to a namespace that capitalizes
3482          *
3483          * @param string $text Containing title to capitalize
3484          * @param int $ns Namespace index, defaults to NS_MAIN
3485          * @return string Containing capitalized title
3486          */
3487         public static function capitalize( $text, $ns = NS_MAIN ) {
3488                 global $wgContLang;
3489
3490                 if ( MWNamespace::isCapitalized( $ns ) ) {
3491                         return $wgContLang->ucfirst( $text );
3492                 } else {
3493                         return $text;
3494                 }
3495         }
3496
3497         /**
3498          * Secure and split - main initialisation function for this object
3499          *
3500          * Assumes that mDbkeyform has been set, and is urldecoded
3501          * and uses underscores, but not otherwise munged.  This function
3502          * removes illegal characters, splits off the interwiki and
3503          * namespace prefixes, sets the other forms, and canonicalizes
3504          * everything.
3505          *
3506          * @throws MalformedTitleException On invalid titles
3507          * @return bool True on success
3508          */
3509         private function secureAndSplit() {
3510                 # Initialisation
3511                 $this->mInterwiki = '';
3512                 $this->mFragment = '';
3513                 $this->mNamespace = $this->mDefaultNamespace; # Usually NS_MAIN
3514
3515                 $dbkey = $this->mDbkeyform;
3516
3517                 // @note: splitTitleString() is a temporary hack to allow MediaWikiTitleCodec to share
3518                 //        the parsing code with Title, while avoiding massive refactoring.
3519                 // @todo: get rid of secureAndSplit, refactor parsing code.
3520                 // @note: getTitleParser() returns a TitleParser implementation which does not have a
3521                 //        splitTitleString method, but the only implementation (MediaWikiTitleCodec) does
3522                 $titleCodec = MediaWikiServices::getInstance()->getTitleParser();
3523                 // MalformedTitleException can be thrown here
3524                 $parts = $titleCodec->splitTitleString( $dbkey, $this->getDefaultNamespace() );
3525
3526                 # Fill fields
3527                 $this->setFragment( '#' . $parts['fragment'] );
3528                 $this->mInterwiki = $parts['interwiki'];
3529                 $this->mLocalInterwiki = $parts['local_interwiki'];
3530                 $this->mNamespace = $parts['namespace'];
3531                 $this->mUserCaseDBKey = $parts['user_case_dbkey'];
3532
3533                 $this->mDbkeyform = $parts['dbkey'];
3534                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
3535                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
3536
3537                 # We already know that some pages won't be in the database!
3538                 if ( $this->isExternal() || $this->isSpecialPage() ) {
3539                         $this->mArticleID = 0;
3540                 }
3541
3542                 return true;
3543         }
3544
3545         /**
3546          * Get an array of Title objects linking to this Title
3547          * Also stores the IDs in the link cache.
3548          *
3549          * WARNING: do not use this function on arbitrary user-supplied titles!
3550          * On heavily-used templates it will max out the memory.
3551          *
3552          * @param array $options May be FOR UPDATE
3553          * @param string $table Table name
3554          * @param string $prefix Fields prefix
3555          * @return Title[] Array of Title objects linking here
3556          */
3557         public function getLinksTo( $options = [], $table = 'pagelinks', $prefix = 'pl' ) {
3558                 if ( count( $options ) > 0 ) {
3559                         $db = wfGetDB( DB_MASTER );
3560                 } else {
3561                         $db = wfGetDB( DB_REPLICA );
3562                 }
3563
3564                 $res = $db->select(
3565                         [ 'page', $table ],
3566                         self::getSelectFields(),
3567                         [
3568                                 "{$prefix}_from=page_id",
3569                                 "{$prefix}_namespace" => $this->getNamespace(),
3570                                 "{$prefix}_title" => $this->getDBkey() ],
3571                         __METHOD__,
3572                         $options
3573                 );
3574
3575                 $retVal = [];
3576                 if ( $res->numRows() ) {
3577                         $linkCache = LinkCache::singleton();
3578                         foreach ( $res as $row ) {
3579                                 $titleObj = self::makeTitle( $row->page_namespace, $row->page_title );
3580                                 if ( $titleObj ) {
3581                                         $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3582                                         $retVal[] = $titleObj;
3583                                 }
3584                         }
3585                 }
3586                 return $retVal;
3587         }
3588
3589         /**
3590          * Get an array of Title objects using this Title as a template
3591          * Also stores the IDs in the link cache.
3592          *
3593          * WARNING: do not use this function on arbitrary user-supplied titles!
3594          * On heavily-used templates it will max out the memory.
3595          *
3596          * @param array $options Query option to Database::select()
3597          * @return Title[] Array of Title the Title objects linking here
3598          */
3599         public function getTemplateLinksTo( $options = [] ) {
3600                 return $this->getLinksTo( $options, 'templatelinks', 'tl' );
3601         }
3602
3603         /**
3604          * Get an array of Title objects linked from this Title
3605          * Also stores the IDs in the link cache.
3606          *
3607          * WARNING: do not use this function on arbitrary user-supplied titles!
3608          * On heavily-used templates it will max out the memory.
3609          *
3610          * @param array $options Query option to Database::select()
3611          * @param string $table Table name
3612          * @param string $prefix Fields prefix
3613          * @return array Array of Title objects linking here
3614          */
3615         public function getLinksFrom( $options = [], $table = 'pagelinks', $prefix = 'pl' ) {
3616                 $id = $this->getArticleID();
3617
3618                 # If the page doesn't exist; there can't be any link from this page
3619                 if ( !$id ) {
3620                         return [];
3621                 }
3622
3623                 $db = wfGetDB( DB_REPLICA );
3624
3625                 $blNamespace = "{$prefix}_namespace";
3626                 $blTitle = "{$prefix}_title";
3627
3628                 $res = $db->select(
3629                         [ $table, 'page' ],
3630                         array_merge(
3631                                 [ $blNamespace, $blTitle ],
3632                                 WikiPage::selectFields()
3633                         ),
3634                         [ "{$prefix}_from" => $id ],
3635                         __METHOD__,
3636                         $options,
3637                         [ 'page' => [
3638                                 'LEFT JOIN',
3639                                 [ "page_namespace=$blNamespace", "page_title=$blTitle" ]
3640                         ] ]
3641                 );
3642
3643                 $retVal = [];
3644                 $linkCache = LinkCache::singleton();
3645                 foreach ( $res as $row ) {
3646                         if ( $row->page_id ) {
3647                                 $titleObj = self::newFromRow( $row );
3648                         } else {
3649                                 $titleObj = self::makeTitle( $row->$blNamespace, $row->$blTitle );
3650                                 $linkCache->addBadLinkObj( $titleObj );
3651                         }
3652                         $retVal[] = $titleObj;
3653                 }
3654
3655                 return $retVal;
3656         }
3657
3658         /**
3659          * Get an array of Title objects used on this Title as a template
3660          * Also stores the IDs in the link cache.
3661          *
3662          * WARNING: do not use this function on arbitrary user-supplied titles!
3663          * On heavily-used templates it will max out the memory.
3664          *
3665          * @param array $options May be FOR UPDATE
3666          * @return Title[] Array of Title the Title objects used here
3667          */
3668         public function getTemplateLinksFrom( $options = [] ) {
3669                 return $this->getLinksFrom( $options, 'templatelinks', 'tl' );
3670         }
3671
3672         /**
3673          * Get an array of Title objects referring to non-existent articles linked
3674          * from this page.
3675          *
3676          * @todo check if needed (used only in SpecialBrokenRedirects.php, and
3677          *   should use redirect table in this case).
3678          * @return Title[] Array of Title the Title objects
3679          */
3680         public function getBrokenLinksFrom() {
3681                 if ( $this->getArticleID() == 0 ) {
3682                         # All links from article ID 0 are false positives
3683                         return [];
3684                 }
3685
3686                 $dbr = wfGetDB( DB_REPLICA );
3687                 $res = $dbr->select(
3688                         [ 'page', 'pagelinks' ],
3689                         [ 'pl_namespace', 'pl_title' ],
3690                         [
3691                                 'pl_from' => $this->getArticleID(),
3692                                 'page_namespace IS NULL'
3693                         ],
3694                         __METHOD__, [],
3695                         [
3696                                 'page' => [
3697                                         'LEFT JOIN',
3698                                         [ 'pl_namespace=page_namespace', 'pl_title=page_title' ]
3699                                 ]
3700                         ]
3701                 );
3702
3703                 $retVal = [];
3704                 foreach ( $res as $row ) {
3705                         $retVal[] = self::makeTitle( $row->pl_namespace, $row->pl_title );
3706                 }
3707                 return $retVal;
3708         }
3709
3710         /**
3711          * Get a list of URLs to purge from the CDN cache when this
3712          * page changes
3713          *
3714          * @return string[] Array of String the URLs
3715          */
3716         public function getCdnUrls() {
3717                 $urls = [
3718                         $this->getInternalURL(),
3719                         $this->getInternalURL( 'action=history' )
3720                 ];
3721
3722                 $pageLang = $this->getPageLanguage();
3723                 if ( $pageLang->hasVariants() ) {
3724                         $variants = $pageLang->getVariants();
3725                         foreach ( $variants as $vCode ) {
3726                                 $urls[] = $this->getInternalURL( $vCode );
3727                         }
3728                 }
3729
3730                 // If we are looking at a css/js user subpage, purge the action=raw.
3731                 if ( $this->isJsSubpage() ) {
3732                         $urls[] = $this->getInternalURL( 'action=raw&ctype=text/javascript' );
3733                 } elseif ( $this->isCssSubpage() ) {
3734                         $urls[] = $this->getInternalURL( 'action=raw&ctype=text/css' );
3735                 }
3736
3737                 Hooks::run( 'TitleSquidURLs', [ $this, &$urls ] );
3738                 return $urls;
3739         }
3740
3741         /**
3742          * @deprecated since 1.27 use getCdnUrls()
3743          */
3744         public function getSquidURLs() {
3745                 return $this->getCdnUrls();
3746         }
3747
3748         /**
3749          * Purge all applicable CDN URLs
3750          */
3751         public function purgeSquid() {
3752                 DeferredUpdates::addUpdate(
3753                         new CdnCacheUpdate( $this->getCdnUrls() ),
3754                         DeferredUpdates::PRESEND
3755                 );
3756         }
3757
3758         /**
3759          * Check whether a given move operation would be valid.
3760          * Returns true if ok, or a getUserPermissionsErrors()-like array otherwise
3761          *
3762          * @deprecated since 1.25, use MovePage's methods instead
3763          * @param Title &$nt The new title
3764          * @param bool $auth Whether to check user permissions (uses $wgUser)
3765          * @param string $reason Is the log summary of the move, used for spam checking
3766          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3767          */
3768         public function isValidMoveOperation( &$nt, $auth = true, $reason = '' ) {
3769                 global $wgUser;
3770
3771                 if ( !( $nt instanceof Title ) ) {
3772                         // Normally we'd add this to $errors, but we'll get
3773                         // lots of syntax errors if $nt is not an object
3774                         return [ [ 'badtitletext' ] ];
3775                 }
3776
3777                 $mp = new MovePage( $this, $nt );
3778                 $errors = $mp->isValidMove()->getErrorsArray();
3779                 if ( $auth ) {
3780                         $errors = wfMergeErrorArrays(
3781                                 $errors,
3782                                 $mp->checkPermissions( $wgUser, $reason )->getErrorsArray()
3783                         );
3784                 }
3785
3786                 return $errors ?: true;
3787         }
3788
3789         /**
3790          * Check if the requested move target is a valid file move target
3791          * @todo move this to MovePage
3792          * @param Title $nt Target title
3793          * @return array List of errors
3794          */
3795         protected function validateFileMoveOperation( $nt ) {
3796                 global $wgUser;
3797
3798                 $errors = [];
3799
3800                 $destFile = wfLocalFile( $nt );
3801                 $destFile->load( File::READ_LATEST );
3802                 if ( !$wgUser->isAllowed( 'reupload-shared' )
3803                         && !$destFile->exists() && wfFindFile( $nt )
3804                 ) {
3805                         $errors[] = [ 'file-exists-sharedrepo' ];
3806                 }
3807
3808                 return $errors;
3809         }
3810
3811         /**
3812          * Move a title to a new location
3813          *
3814          * @deprecated since 1.25, use the MovePage class instead
3815          * @param Title &$nt The new title
3816          * @param bool $auth Indicates whether $wgUser's permissions
3817          *  should be checked
3818          * @param string $reason The reason for the move
3819          * @param bool $createRedirect Whether to create a redirect from the old title to the new title.
3820          *  Ignored if the user doesn't have the suppressredirect right.
3821          * @param array $changeTags Applied to the entry in the move log and redirect page revision
3822          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3823          */
3824         public function moveTo( &$nt, $auth = true, $reason = '', $createRedirect = true,
3825                 array $changeTags = []
3826         ) {
3827                 global $wgUser;
3828                 $err = $this->isValidMoveOperation( $nt, $auth, $reason );
3829                 if ( is_array( $err ) ) {
3830                         // Auto-block user's IP if the account was "hard" blocked
3831                         $wgUser->spreadAnyEditBlock();
3832                         return $err;
3833                 }
3834                 // Check suppressredirect permission
3835                 if ( $auth && !$wgUser->isAllowed( 'suppressredirect' ) ) {
3836                         $createRedirect = true;
3837                 }
3838
3839                 $mp = new MovePage( $this, $nt );
3840                 $status = $mp->move( $wgUser, $reason, $createRedirect, $changeTags );
3841                 if ( $status->isOK() ) {
3842                         return true;
3843                 } else {
3844                         return $status->getErrorsArray();
3845                 }
3846         }
3847
3848         /**
3849          * Move this page's subpages to be subpages of $nt
3850          *
3851          * @param Title $nt Move target
3852          * @param bool $auth Whether $wgUser's permissions should be checked
3853          * @param string $reason The reason for the move
3854          * @param bool $createRedirect Whether to create redirects from the old subpages to
3855          *     the new ones Ignored if the user doesn't have the 'suppressredirect' right
3856          * @param array $changeTags Applied to the entry in the move log and redirect page revision
3857          * @return array Array with old page titles as keys, and strings (new page titles) or
3858          *     getUserPermissionsErrors()-like arrays (errors) as values, or a
3859          *     getUserPermissionsErrors()-like error array with numeric indices if
3860          *     no pages were moved
3861          */
3862         public function moveSubpages( $nt, $auth = true, $reason = '', $createRedirect = true,
3863                 array $changeTags = []
3864         ) {
3865                 global $wgMaximumMovedPages;
3866                 // Check permissions
3867                 if ( !$this->userCan( 'move-subpages' ) ) {
3868                         return [
3869                                 [ 'cant-move-subpages' ],
3870                         ];
3871                 }
3872                 // Do the source and target namespaces support subpages?
3873                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3874                         return [
3875                                 [ 'namespace-nosubpages', MWNamespace::getCanonicalName( $this->getNamespace() ) ],
3876                         ];
3877                 }
3878                 if ( !MWNamespace::hasSubpages( $nt->getNamespace() ) ) {
3879                         return [
3880                                 [ 'namespace-nosubpages', MWNamespace::getCanonicalName( $nt->getNamespace() ) ],
3881                         ];
3882                 }
3883
3884                 $subpages = $this->getSubpages( $wgMaximumMovedPages + 1 );
3885                 $retval = [];
3886                 $count = 0;
3887                 foreach ( $subpages as $oldSubpage ) {
3888                         $count++;
3889                         if ( $count > $wgMaximumMovedPages ) {
3890                                 $retval[$oldSubpage->getPrefixedText()] = [
3891                                         [ 'movepage-max-pages', $wgMaximumMovedPages ],
3892                                 ];
3893                                 break;
3894                         }
3895
3896                         // We don't know whether this function was called before
3897                         // or after moving the root page, so check both
3898                         // $this and $nt
3899                         if ( $oldSubpage->getArticleID() == $this->getArticleID()
3900                                 || $oldSubpage->getArticleID() == $nt->getArticleID()
3901                         ) {
3902                                 // When moving a page to a subpage of itself,
3903                                 // don't move it twice
3904                                 continue;
3905                         }
3906                         $newPageName = preg_replace(
3907                                         '#^' . preg_quote( $this->getDBkey(), '#' ) . '#',
3908                                         StringUtils::escapeRegexReplacement( $nt->getDBkey() ), # T23234
3909                                         $oldSubpage->getDBkey() );
3910                         if ( $oldSubpage->isTalkPage() ) {
3911                                 $newNs = $nt->getTalkPage()->getNamespace();
3912                         } else {
3913                                 $newNs = $nt->getSubjectPage()->getNamespace();
3914                         }
3915                         # T16385: we need makeTitleSafe because the new page names may
3916                         # be longer than 255 characters.
3917                         $newSubpage = self::makeTitleSafe( $newNs, $newPageName );
3918
3919                         $success = $oldSubpage->moveTo( $newSubpage, $auth, $reason, $createRedirect, $changeTags );
3920                         if ( $success === true ) {
3921                                 $retval[$oldSubpage->getPrefixedText()] = $newSubpage->getPrefixedText();
3922                         } else {
3923                                 $retval[$oldSubpage->getPrefixedText()] = $success;
3924                         }
3925                 }
3926                 return $retval;
3927         }
3928
3929         /**
3930          * Checks if this page is just a one-rev redirect.
3931          * Adds lock, so don't use just for light purposes.
3932          *
3933          * @return bool
3934          */
3935         public function isSingleRevRedirect() {
3936                 global $wgContentHandlerUseDB;
3937
3938                 $dbw = wfGetDB( DB_MASTER );
3939
3940                 # Is it a redirect?
3941                 $fields = [ 'page_is_redirect', 'page_latest', 'page_id' ];
3942                 if ( $wgContentHandlerUseDB ) {
3943                         $fields[] = 'page_content_model';
3944                 }
3945
3946                 $row = $dbw->selectRow( 'page',
3947                         $fields,
3948                         $this->pageCond(),
3949                         __METHOD__,
3950                         [ 'FOR UPDATE' ]
3951                 );
3952                 # Cache some fields we may want
3953                 $this->mArticleID = $row ? intval( $row->page_id ) : 0;
3954                 $this->mRedirect = $row ? (bool)$row->page_is_redirect : false;
3955                 $this->mLatestID = $row ? intval( $row->page_latest ) : false;
3956                 $this->mContentModel = $row && isset( $row->page_content_model )
3957                         ? strval( $row->page_content_model )
3958                         : false;
3959
3960                 if ( !$this->mRedirect ) {
3961                         return false;
3962                 }
3963                 # Does the article have a history?
3964                 $row = $dbw->selectField( [ 'page', 'revision' ],
3965                         'rev_id',
3966                         [ 'page_namespace' => $this->getNamespace(),
3967                                 'page_title' => $this->getDBkey(),
3968                                 'page_id=rev_page',
3969                                 'page_latest != rev_id'
3970                         ],
3971                         __METHOD__,
3972                         [ 'FOR UPDATE' ]
3973                 );
3974                 # Return true if there was no history
3975                 return ( $row === false );
3976         }
3977
3978         /**
3979          * Checks if $this can be moved to a given Title
3980          * - Selects for update, so don't call it unless you mean business
3981          *
3982          * @deprecated since 1.25, use MovePage's methods instead
3983          * @param Title $nt The new title to check
3984          * @return bool
3985          */
3986         public function isValidMoveTarget( $nt ) {
3987                 # Is it an existing file?
3988                 if ( $nt->getNamespace() == NS_FILE ) {
3989                         $file = wfLocalFile( $nt );
3990                         $file->load( File::READ_LATEST );
3991                         if ( $file->exists() ) {
3992                                 wfDebug( __METHOD__ . ": file exists\n" );
3993                                 return false;
3994                         }
3995                 }
3996                 # Is it a redirect with no history?
3997                 if ( !$nt->isSingleRevRedirect() ) {
3998                         wfDebug( __METHOD__ . ": not a one-rev redirect\n" );
3999                         return false;
4000                 }
4001                 # Get the article text
4002                 $rev = Revision::newFromTitle( $nt, false, Revision::READ_LATEST );
4003                 if ( !is_object( $rev ) ) {
4004                         return false;
4005                 }
4006                 $content = $rev->getContent();
4007                 # Does the redirect point to the source?
4008                 # Or is it a broken self-redirect, usually caused by namespace collisions?
4009                 $redirTitle = $content ? $content->getRedirectTarget() : null;
4010
4011                 if ( $redirTitle ) {
4012                         if ( $redirTitle->getPrefixedDBkey() != $this->getPrefixedDBkey() &&
4013                                 $redirTitle->getPrefixedDBkey() != $nt->getPrefixedDBkey() ) {
4014                                 wfDebug( __METHOD__ . ": redirect points to other page\n" );
4015                                 return false;
4016                         } else {
4017                                 return true;
4018                         }
4019                 } else {
4020                         # Fail safe (not a redirect after all. strange.)
4021                         wfDebug( __METHOD__ . ": failsafe: database sais " . $nt->getPrefixedDBkey() .
4022                                                 " is a redirect, but it doesn't contain a valid redirect.\n" );
4023                         return false;
4024                 }
4025         }
4026
4027         /**
4028          * Get categories to which this Title belongs and return an array of
4029          * categories' names.
4030          *
4031          * @return array Array of parents in the form:
4032          *     $parent => $currentarticle
4033          */
4034         public function getParentCategories() {
4035                 global $wgContLang;
4036
4037                 $data = [];
4038
4039                 $titleKey = $this->getArticleID();
4040
4041                 if ( $titleKey === 0 ) {
4042                         return $data;
4043                 }
4044
4045                 $dbr = wfGetDB( DB_REPLICA );
4046
4047                 $res = $dbr->select(
4048                         'categorylinks',
4049                         'cl_to',
4050                         [ 'cl_from' => $titleKey ],
4051                         __METHOD__
4052                 );
4053
4054                 if ( $res->numRows() > 0 ) {
4055                         foreach ( $res as $row ) {
4056                                 // $data[] = Title::newFromText($wgContLang->getNsText ( NS_CATEGORY ).':'.$row->cl_to);
4057                                 $data[$wgContLang->getNsText( NS_CATEGORY ) . ':' . $row->cl_to] = $this->getFullText();
4058                         }
4059                 }
4060                 return $data;
4061         }
4062
4063         /**
4064          * Get a tree of parent categories
4065          *
4066          * @param array $children Array with the children in the keys, to check for circular refs
4067          * @return array Tree of parent categories
4068          */
4069         public function getParentCategoryTree( $children = [] ) {
4070                 $stack = [];
4071                 $parents = $this->getParentCategories();
4072
4073                 if ( $parents ) {
4074                         foreach ( $parents as $parent => $current ) {
4075                                 if ( array_key_exists( $parent, $children ) ) {
4076                                         # Circular reference
4077                                         $stack[$parent] = [];
4078                                 } else {
4079                                         $nt = self::newFromText( $parent );
4080                                         if ( $nt ) {
4081                                                 $stack[$parent] = $nt->getParentCategoryTree( $children + [ $parent => 1 ] );
4082                                         }
4083                                 }
4084                         }
4085                 }
4086
4087                 return $stack;
4088         }
4089
4090         /**
4091          * Get an associative array for selecting this title from
4092          * the "page" table
4093          *
4094          * @return array Array suitable for the $where parameter of DB::select()
4095          */
4096         public function pageCond() {
4097                 if ( $this->mArticleID > 0 ) {
4098                         // PK avoids secondary lookups in InnoDB, shouldn't hurt other DBs
4099                         return [ 'page_id' => $this->mArticleID ];
4100                 } else {
4101                         return [ 'page_namespace' => $this->mNamespace, 'page_title' => $this->mDbkeyform ];
4102                 }
4103         }
4104
4105         /**
4106          * Get next/previous revision ID relative to another revision ID
4107          * @param int $revId Revision ID. Get the revision that was before this one.
4108          * @param int $flags Title::GAID_FOR_UPDATE
4109          * @param string $dir 'next' or 'prev'
4110          * @return int|bool New revision ID, or false if none exists
4111          */
4112         private function getRelativeRevisionID( $revId, $flags, $dir ) {
4113                 $revId = (int)$revId;
4114                 if ( $dir === 'next' ) {
4115                         $op = '>';
4116                         $sort = 'ASC';
4117                 } elseif ( $dir === 'prev' ) {
4118                         $op = '<';
4119                         $sort = 'DESC';
4120                 } else {
4121                         throw new InvalidArgumentException( '$dir must be "next" or "prev"' );
4122                 }
4123
4124                 if ( $flags & self::GAID_FOR_UPDATE ) {
4125                         $db = wfGetDB( DB_MASTER );
4126                 } else {
4127                         $db = wfGetDB( DB_REPLICA, 'contributions' );
4128                 }
4129
4130                 // Intentionally not caring if the specified revision belongs to this
4131                 // page. We only care about the timestamp.
4132                 $ts = $db->selectField( 'revision', 'rev_timestamp', [ 'rev_id' => $revId ], __METHOD__ );
4133                 if ( $ts === false ) {
4134                         $ts = $db->selectField( 'archive', 'ar_timestamp', [ 'ar_rev_id' => $revId ], __METHOD__ );
4135                         if ( $ts === false ) {
4136                                 // Or should this throw an InvalidArgumentException or something?
4137                                 return false;
4138                         }
4139                 }
4140                 $ts = $db->addQuotes( $ts );
4141
4142                 $revId = $db->selectField( 'revision', 'rev_id',
4143                         [
4144                                 'rev_page' => $this->getArticleID( $flags ),
4145                                 "rev_timestamp $op $ts OR (rev_timestamp = $ts AND rev_id $op $revId)"
4146                         ],
4147                         __METHOD__,
4148                         [
4149                                 'ORDER BY' => "rev_timestamp $sort, rev_id $sort",
4150                                 'IGNORE INDEX' => 'rev_timestamp', // Probably needed for T159319
4151                         ]
4152                 );
4153
4154                 if ( $revId === false ) {
4155                         return false;
4156                 } else {
4157                         return intval( $revId );
4158                 }
4159         }
4160
4161         /**
4162          * Get the revision ID of the previous revision
4163          *
4164          * @param int $revId Revision ID. Get the revision that was before this one.
4165          * @param int $flags Title::GAID_FOR_UPDATE
4166          * @return int|bool Old revision ID, or false if none exists
4167          */
4168         public function getPreviousRevisionID( $revId, $flags = 0 ) {
4169                 return $this->getRelativeRevisionID( $revId, $flags, 'prev' );
4170         }
4171
4172         /**
4173          * Get the revision ID of the next revision
4174          *
4175          * @param int $revId Revision ID. Get the revision that was after this one.
4176          * @param int $flags Title::GAID_FOR_UPDATE
4177          * @return int|bool Next revision ID, or false if none exists
4178          */
4179         public function getNextRevisionID( $revId, $flags = 0 ) {
4180                 return $this->getRelativeRevisionID( $revId, $flags, 'next' );
4181         }
4182
4183         /**
4184          * Get the first revision of the page
4185          *
4186          * @param int $flags Title::GAID_FOR_UPDATE
4187          * @return Revision|null If page doesn't exist
4188          */
4189         public function getFirstRevision( $flags = 0 ) {
4190                 $pageId = $this->getArticleID( $flags );
4191                 if ( $pageId ) {
4192                         $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_REPLICA );
4193                         $row = $db->selectRow( 'revision', Revision::selectFields(),
4194                                 [ 'rev_page' => $pageId ],
4195                                 __METHOD__,
4196                                 [
4197                                         'ORDER BY' => 'rev_timestamp ASC, rev_id ASC',
4198                                         'IGNORE INDEX' => 'rev_timestamp', // See T159319
4199                                 ]
4200                         );
4201                         if ( $row ) {
4202                                 return new Revision( $row );
4203                         }
4204                 }
4205                 return null;
4206         }
4207
4208         /**
4209          * Get the oldest revision timestamp of this page
4210          *
4211          * @param int $flags Title::GAID_FOR_UPDATE
4212          * @return string MW timestamp
4213          */
4214         public function getEarliestRevTime( $flags = 0 ) {
4215                 $rev = $this->getFirstRevision( $flags );
4216                 return $rev ? $rev->getTimestamp() : null;
4217         }
4218
4219         /**
4220          * Check if this is a new page
4221          *
4222          * @return bool
4223          */
4224         public function isNewPage() {
4225                 $dbr = wfGetDB( DB_REPLICA );
4226                 return (bool)$dbr->selectField( 'page', 'page_is_new', $this->pageCond(), __METHOD__ );
4227         }
4228
4229         /**
4230          * Check whether the number of revisions of this page surpasses $wgDeleteRevisionsLimit
4231          *
4232          * @return bool
4233          */
4234         public function isBigDeletion() {
4235                 global $wgDeleteRevisionsLimit;
4236
4237                 if ( !$wgDeleteRevisionsLimit ) {
4238                         return false;
4239                 }
4240
4241                 if ( $this->mIsBigDeletion === null ) {
4242                         $dbr = wfGetDB( DB_REPLICA );
4243
4244                         $revCount = $dbr->selectRowCount(
4245                                 'revision',
4246                                 '1',
4247                                 [ 'rev_page' => $this->getArticleID() ],
4248                                 __METHOD__,
4249                                 [ 'LIMIT' => $wgDeleteRevisionsLimit + 1 ]
4250                         );
4251
4252                         $this->mIsBigDeletion = $revCount > $wgDeleteRevisionsLimit;
4253                 }
4254
4255                 return $this->mIsBigDeletion;
4256         }
4257
4258         /**
4259          * Get the approximate revision count of this page.
4260          *
4261          * @return int
4262          */
4263         public function estimateRevisionCount() {
4264                 if ( !$this->exists() ) {
4265                         return 0;
4266                 }
4267
4268                 if ( $this->mEstimateRevisions === null ) {
4269                         $dbr = wfGetDB( DB_REPLICA );
4270                         $this->mEstimateRevisions = $dbr->estimateRowCount( 'revision', '*',
4271                                 [ 'rev_page' => $this->getArticleID() ], __METHOD__ );
4272                 }
4273
4274                 return $this->mEstimateRevisions;
4275         }
4276
4277         /**
4278          * Get the number of revisions between the given revision.
4279          * Used for diffs and other things that really need it.
4280          *
4281          * @param int|Revision $old Old revision or rev ID (first before range)
4282          * @param int|Revision $new New revision or rev ID (first after range)
4283          * @param int|null $max Limit of Revisions to count, will be incremented to detect truncations
4284          * @return int Number of revisions between these revisions.
4285          */
4286         public function countRevisionsBetween( $old, $new, $max = null ) {
4287                 if ( !( $old instanceof Revision ) ) {
4288                         $old = Revision::newFromTitle( $this, (int)$old );
4289                 }
4290                 if ( !( $new instanceof Revision ) ) {
4291                         $new = Revision::newFromTitle( $this, (int)$new );
4292                 }
4293                 if ( !$old || !$new ) {
4294                         return 0; // nothing to compare
4295                 }
4296                 $dbr = wfGetDB( DB_REPLICA );
4297                 $conds = [
4298                         'rev_page' => $this->getArticleID(),
4299                         'rev_timestamp > ' . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4300                         'rev_timestamp < ' . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4301                 ];
4302                 if ( $max !== null ) {
4303                         return $dbr->selectRowCount( 'revision', '1',
4304                                 $conds,
4305                                 __METHOD__,
4306                                 [ 'LIMIT' => $max + 1 ] // extra to detect truncation
4307                         );
4308                 } else {
4309                         return (int)$dbr->selectField( 'revision', 'count(*)', $conds, __METHOD__ );
4310                 }
4311         }
4312
4313         /**
4314          * Get the authors between the given revisions or revision IDs.
4315          * Used for diffs and other things that really need it.
4316          *
4317          * @since 1.23
4318          *
4319          * @param int|Revision $old Old revision or rev ID (first before range by default)
4320          * @param int|Revision $new New revision or rev ID (first after range by default)
4321          * @param int $limit Maximum number of authors
4322          * @param string|array $options (Optional): Single option, or an array of options:
4323          *     'include_old' Include $old in the range; $new is excluded.
4324          *     'include_new' Include $new in the range; $old is excluded.
4325          *     'include_both' Include both $old and $new in the range.
4326          *     Unknown option values are ignored.
4327          * @return array|null Names of revision authors in the range; null if not both revisions exist
4328          */
4329         public function getAuthorsBetween( $old, $new, $limit, $options = [] ) {
4330                 if ( !( $old instanceof Revision ) ) {
4331                         $old = Revision::newFromTitle( $this, (int)$old );
4332                 }
4333                 if ( !( $new instanceof Revision ) ) {
4334                         $new = Revision::newFromTitle( $this, (int)$new );
4335                 }
4336                 // XXX: what if Revision objects are passed in, but they don't refer to this title?
4337                 // Add $old->getPage() != $new->getPage() || $old->getPage() != $this->getArticleID()
4338                 // in the sanity check below?
4339                 if ( !$old || !$new ) {
4340                         return null; // nothing to compare
4341                 }
4342                 $authors = [];
4343                 $old_cmp = '>';
4344                 $new_cmp = '<';
4345                 $options = (array)$options;
4346                 if ( in_array( 'include_old', $options ) ) {
4347                         $old_cmp = '>=';
4348                 }
4349                 if ( in_array( 'include_new', $options ) ) {
4350                         $new_cmp = '<=';
4351                 }
4352                 if ( in_array( 'include_both', $options ) ) {
4353                         $old_cmp = '>=';
4354                         $new_cmp = '<=';
4355                 }
4356                 // No DB query needed if $old and $new are the same or successive revisions:
4357                 if ( $old->getId() === $new->getId() ) {
4358                         return ( $old_cmp === '>' && $new_cmp === '<' ) ?
4359                                 [] :
4360                                 [ $old->getUserText( Revision::RAW ) ];
4361                 } elseif ( $old->getId() === $new->getParentId() ) {
4362                         if ( $old_cmp === '>=' && $new_cmp === '<=' ) {
4363                                 $authors[] = $old->getUserText( Revision::RAW );
4364                                 if ( $old->getUserText( Revision::RAW ) != $new->getUserText( Revision::RAW ) ) {
4365                                         $authors[] = $new->getUserText( Revision::RAW );
4366                                 }
4367                         } elseif ( $old_cmp === '>=' ) {
4368                                 $authors[] = $old->getUserText( Revision::RAW );
4369                         } elseif ( $new_cmp === '<=' ) {
4370                                 $authors[] = $new->getUserText( Revision::RAW );
4371                         }
4372                         return $authors;
4373                 }
4374                 $dbr = wfGetDB( DB_REPLICA );
4375                 $res = $dbr->select( 'revision', 'DISTINCT rev_user_text',
4376                         [
4377                                 'rev_page' => $this->getArticleID(),
4378                                 "rev_timestamp $old_cmp " . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4379                                 "rev_timestamp $new_cmp " . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4380                         ], __METHOD__,
4381                         [ 'LIMIT' => $limit + 1 ] // add one so caller knows it was truncated
4382                 );
4383                 foreach ( $res as $row ) {
4384                         $authors[] = $row->rev_user_text;
4385                 }
4386                 return $authors;
4387         }
4388
4389         /**
4390          * Get the number of authors between the given revisions or revision IDs.
4391          * Used for diffs and other things that really need it.
4392          *
4393          * @param int|Revision $old Old revision or rev ID (first before range by default)
4394          * @param int|Revision $new New revision or rev ID (first after range by default)
4395          * @param int $limit Maximum number of authors
4396          * @param string|array $options (Optional): Single option, or an array of options:
4397          *     'include_old' Include $old in the range; $new is excluded.
4398          *     'include_new' Include $new in the range; $old is excluded.
4399          *     'include_both' Include both $old and $new in the range.
4400          *     Unknown option values are ignored.
4401          * @return int Number of revision authors in the range; zero if not both revisions exist
4402          */
4403         public function countAuthorsBetween( $old, $new, $limit, $options = [] ) {
4404                 $authors = $this->getAuthorsBetween( $old, $new, $limit, $options );
4405                 return $authors ? count( $authors ) : 0;
4406         }
4407
4408         /**
4409          * Compare with another title.
4410          *
4411          * @param Title $title
4412          * @return bool
4413          */
4414         public function equals( Title $title ) {
4415                 // Note: === is necessary for proper matching of number-like titles.
4416                 return $this->getInterwiki() === $title->getInterwiki()
4417                         && $this->getNamespace() == $title->getNamespace()
4418                         && $this->getDBkey() === $title->getDBkey();
4419         }
4420
4421         /**
4422          * Check if this title is a subpage of another title
4423          *
4424          * @param Title $title
4425          * @return bool
4426          */
4427         public function isSubpageOf( Title $title ) {
4428                 return $this->getInterwiki() === $title->getInterwiki()
4429                         && $this->getNamespace() == $title->getNamespace()
4430                         && strpos( $this->getDBkey(), $title->getDBkey() . '/' ) === 0;
4431         }
4432
4433         /**
4434          * Check if page exists.  For historical reasons, this function simply
4435          * checks for the existence of the title in the page table, and will
4436          * thus return false for interwiki links, special pages and the like.
4437          * If you want to know if a title can be meaningfully viewed, you should
4438          * probably call the isKnown() method instead.
4439          *
4440          * @param int $flags An optional bit field; may be Title::GAID_FOR_UPDATE to check
4441          *   from master/for update
4442          * @return bool
4443          */
4444         public function exists( $flags = 0 ) {
4445                 $exists = $this->getArticleID( $flags ) != 0;
4446                 Hooks::run( 'TitleExists', [ $this, &$exists ] );
4447                 return $exists;
4448         }
4449
4450         /**
4451          * Should links to this title be shown as potentially viewable (i.e. as
4452          * "bluelinks"), even if there's no record by this title in the page
4453          * table?
4454          *
4455          * This function is semi-deprecated for public use, as well as somewhat
4456          * misleadingly named.  You probably just want to call isKnown(), which
4457          * calls this function internally.
4458          *
4459          * (ISSUE: Most of these checks are cheap, but the file existence check
4460          * can potentially be quite expensive.  Including it here fixes a lot of
4461          * existing code, but we might want to add an optional parameter to skip
4462          * it and any other expensive checks.)
4463          *
4464          * @return bool
4465          */
4466         public function isAlwaysKnown() {
4467                 $isKnown = null;
4468
4469                 /**
4470                  * Allows overriding default behavior for determining if a page exists.
4471                  * If $isKnown is kept as null, regular checks happen. If it's
4472                  * a boolean, this value is returned by the isKnown method.
4473                  *
4474                  * @since 1.20
4475                  *
4476                  * @param Title $title
4477                  * @param bool|null $isKnown
4478                  */
4479                 Hooks::run( 'TitleIsAlwaysKnown', [ $this, &$isKnown ] );
4480
4481                 if ( !is_null( $isKnown ) ) {
4482                         return $isKnown;
4483                 }
4484
4485                 if ( $this->isExternal() ) {
4486                         return true;  // any interwiki link might be viewable, for all we know
4487                 }
4488
4489                 switch ( $this->mNamespace ) {
4490                         case NS_MEDIA:
4491                         case NS_FILE:
4492                                 // file exists, possibly in a foreign repo
4493                                 return (bool)wfFindFile( $this );
4494                         case NS_SPECIAL:
4495                                 // valid special page
4496                                 return SpecialPageFactory::exists( $this->getDBkey() );
4497                         case NS_MAIN:
4498                                 // selflink, possibly with fragment
4499                                 return $this->mDbkeyform == '';
4500                         case NS_MEDIAWIKI:
4501                                 // known system message
4502                                 return $this->hasSourceText() !== false;
4503                         default:
4504                                 return false;
4505                 }
4506         }
4507
4508         /**
4509          * Does this title refer to a page that can (or might) be meaningfully
4510          * viewed?  In particular, this function may be used to determine if
4511          * links to the title should be rendered as "bluelinks" (as opposed to
4512          * "redlinks" to non-existent pages).
4513          * Adding something else to this function will cause inconsistency
4514          * since LinkHolderArray calls isAlwaysKnown() and does its own
4515          * page existence check.
4516          *
4517          * @return bool
4518          */
4519         public function isKnown() {
4520                 return $this->isAlwaysKnown() || $this->exists();
4521         }
4522
4523         /**
4524          * Does this page have source text?
4525          *
4526          * @return bool
4527          */
4528         public function hasSourceText() {
4529                 if ( $this->exists() ) {
4530                         return true;
4531                 }
4532
4533                 if ( $this->mNamespace == NS_MEDIAWIKI ) {
4534                         // If the page doesn't exist but is a known system message, default
4535                         // message content will be displayed, same for language subpages-
4536                         // Use always content language to avoid loading hundreds of languages
4537                         // to get the link color.
4538                         global $wgContLang;
4539                         list( $name, ) = MessageCache::singleton()->figureMessage(
4540                                 $wgContLang->lcfirst( $this->getText() )
4541                         );
4542                         $message = wfMessage( $name )->inLanguage( $wgContLang )->useDatabase( false );
4543                         return $message->exists();
4544                 }
4545
4546                 return false;
4547         }
4548
4549         /**
4550          * Get the default message text or false if the message doesn't exist
4551          *
4552          * @return string|bool
4553          */
4554         public function getDefaultMessageText() {
4555                 global $wgContLang;
4556
4557                 if ( $this->getNamespace() != NS_MEDIAWIKI ) { // Just in case
4558                         return false;
4559                 }
4560
4561                 list( $name, $lang ) = MessageCache::singleton()->figureMessage(
4562                         $wgContLang->lcfirst( $this->getText() )
4563                 );
4564                 $message = wfMessage( $name )->inLanguage( $lang )->useDatabase( false );
4565
4566                 if ( $message->exists() ) {
4567                         return $message->plain();
4568                 } else {
4569                         return false;
4570                 }
4571         }
4572
4573         /**
4574          * Updates page_touched for this page; called from LinksUpdate.php
4575          *
4576          * @param string $purgeTime [optional] TS_MW timestamp
4577          * @return bool True if the update succeeded
4578          */
4579         public function invalidateCache( $purgeTime = null ) {
4580                 if ( wfReadOnly() ) {
4581                         return false;
4582                 } elseif ( $this->mArticleID === 0 ) {
4583                         return true; // avoid gap locking if we know it's not there
4584                 }
4585
4586                 $dbw = wfGetDB( DB_MASTER );
4587                 $dbw->onTransactionPreCommitOrIdle( function () {
4588                         ResourceLoaderWikiModule::invalidateModuleCache( $this, null, null, wfWikiID() );
4589                 } );
4590
4591                 $conds = $this->pageCond();
4592                 DeferredUpdates::addUpdate(
4593                         new AutoCommitUpdate(
4594                                 $dbw,
4595                                 __METHOD__,
4596                                 function ( IDatabase $dbw, $fname ) use ( $conds, $purgeTime ) {
4597                                         $dbTimestamp = $dbw->timestamp( $purgeTime ?: time() );
4598                                         $dbw->update(
4599                                                 'page',
4600                                                 [ 'page_touched' => $dbTimestamp ],
4601                                                 $conds + [ 'page_touched < ' . $dbw->addQuotes( $dbTimestamp ) ],
4602                                                 $fname
4603                                         );
4604                                         MediaWikiServices::getInstance()->getLinkCache()->invalidateTitle( $this );
4605                                 }
4606                         ),
4607                         DeferredUpdates::PRESEND
4608                 );
4609
4610                 return true;
4611         }
4612
4613         /**
4614          * Update page_touched timestamps and send CDN purge messages for
4615          * pages linking to this title. May be sent to the job queue depending
4616          * on the number of links. Typically called on create and delete.
4617          */
4618         public function touchLinks() {
4619                 DeferredUpdates::addUpdate( new HTMLCacheUpdate( $this, 'pagelinks' ) );
4620                 if ( $this->getNamespace() == NS_CATEGORY ) {
4621                         DeferredUpdates::addUpdate( new HTMLCacheUpdate( $this, 'categorylinks' ) );
4622                 }
4623         }
4624
4625         /**
4626          * Get the last touched timestamp
4627          *
4628          * @param IDatabase $db Optional db
4629          * @return string|false Last-touched timestamp
4630          */
4631         public function getTouched( $db = null ) {
4632                 if ( $db === null ) {
4633                         $db = wfGetDB( DB_REPLICA );
4634                 }
4635                 $touched = $db->selectField( 'page', 'page_touched', $this->pageCond(), __METHOD__ );
4636                 return $touched;
4637         }
4638
4639         /**
4640          * Get the timestamp when this page was updated since the user last saw it.
4641          *
4642          * @param User $user
4643          * @return string|null
4644          */
4645         public function getNotificationTimestamp( $user = null ) {
4646                 global $wgUser;
4647
4648                 // Assume current user if none given
4649                 if ( !$user ) {
4650                         $user = $wgUser;
4651                 }
4652                 // Check cache first
4653                 $uid = $user->getId();
4654                 if ( !$uid ) {
4655                         return false;
4656                 }
4657                 // avoid isset here, as it'll return false for null entries
4658                 if ( array_key_exists( $uid, $this->mNotificationTimestamp ) ) {
4659                         return $this->mNotificationTimestamp[$uid];
4660                 }
4661                 // Don't cache too much!
4662                 if ( count( $this->mNotificationTimestamp ) >= self::CACHE_MAX ) {
4663                         $this->mNotificationTimestamp = [];
4664                 }
4665
4666                 $store = MediaWikiServices::getInstance()->getWatchedItemStore();
4667                 $watchedItem = $store->getWatchedItem( $user, $this );
4668                 if ( $watchedItem ) {
4669                         $this->mNotificationTimestamp[$uid] = $watchedItem->getNotificationTimestamp();
4670                 } else {
4671                         $this->mNotificationTimestamp[$uid] = false;
4672                 }
4673
4674                 return $this->mNotificationTimestamp[$uid];
4675         }
4676
4677         /**
4678          * Generate strings used for xml 'id' names in monobook tabs
4679          *
4680          * @param string $prepend Defaults to 'nstab-'
4681          * @return string XML 'id' name
4682          */
4683         public function getNamespaceKey( $prepend = 'nstab-' ) {
4684                 global $wgContLang;
4685                 // Gets the subject namespace if this title
4686                 $namespace = MWNamespace::getSubject( $this->getNamespace() );
4687                 // Checks if canonical namespace name exists for namespace
4688                 if ( MWNamespace::exists( $this->getNamespace() ) ) {
4689                         // Uses canonical namespace name
4690                         $namespaceKey = MWNamespace::getCanonicalName( $namespace );
4691                 } else {
4692                         // Uses text of namespace
4693                         $namespaceKey = $this->getSubjectNsText();
4694                 }
4695                 // Makes namespace key lowercase
4696                 $namespaceKey = $wgContLang->lc( $namespaceKey );
4697                 // Uses main
4698                 if ( $namespaceKey == '' ) {
4699                         $namespaceKey = 'main';
4700                 }
4701                 // Changes file to image for backwards compatibility
4702                 if ( $namespaceKey == 'file' ) {
4703                         $namespaceKey = 'image';
4704                 }
4705                 return $prepend . $namespaceKey;
4706         }
4707
4708         /**
4709          * Get all extant redirects to this Title
4710          *
4711          * @param int|null $ns Single namespace to consider; null to consider all namespaces
4712          * @return Title[] Array of Title redirects to this title
4713          */
4714         public function getRedirectsHere( $ns = null ) {
4715                 $redirs = [];
4716
4717                 $dbr = wfGetDB( DB_REPLICA );
4718                 $where = [
4719                         'rd_namespace' => $this->getNamespace(),
4720                         'rd_title' => $this->getDBkey(),
4721                         'rd_from = page_id'
4722                 ];
4723                 if ( $this->isExternal() ) {
4724                         $where['rd_interwiki'] = $this->getInterwiki();
4725                 } else {
4726                         $where[] = 'rd_interwiki = ' . $dbr->addQuotes( '' ) . ' OR rd_interwiki IS NULL';
4727                 }
4728                 if ( !is_null( $ns ) ) {
4729                         $where['page_namespace'] = $ns;
4730                 }
4731
4732                 $res = $dbr->select(
4733                         [ 'redirect', 'page' ],
4734                         [ 'page_namespace', 'page_title' ],
4735                         $where,
4736                         __METHOD__
4737                 );
4738
4739                 foreach ( $res as $row ) {
4740                         $redirs[] = self::newFromRow( $row );
4741                 }
4742                 return $redirs;
4743         }
4744
4745         /**
4746          * Check if this Title is a valid redirect target
4747          *
4748          * @return bool
4749          */
4750         public function isValidRedirectTarget() {
4751                 global $wgInvalidRedirectTargets;
4752
4753                 if ( $this->isSpecialPage() ) {
4754                         // invalid redirect targets are stored in a global array, but explicitly disallow Userlogout here
4755                         if ( $this->isSpecial( 'Userlogout' ) ) {
4756                                 return false;
4757                         }
4758
4759                         foreach ( $wgInvalidRedirectTargets as $target ) {
4760                                 if ( $this->isSpecial( $target ) ) {
4761                                         return false;
4762                                 }
4763                         }
4764                 }
4765
4766                 return true;
4767         }
4768
4769         /**
4770          * Get a backlink cache object
4771          *
4772          * @return BacklinkCache
4773          */
4774         public function getBacklinkCache() {
4775                 return BacklinkCache::get( $this );
4776         }
4777
4778         /**
4779          * Whether the magic words __INDEX__ and __NOINDEX__ function for this page.
4780          *
4781          * @return bool
4782          */
4783         public function canUseNoindex() {
4784                 global $wgExemptFromUserRobotsControl;
4785
4786                 $bannedNamespaces = is_null( $wgExemptFromUserRobotsControl )
4787                         ? MWNamespace::getContentNamespaces()
4788                         : $wgExemptFromUserRobotsControl;
4789
4790                 return !in_array( $this->mNamespace, $bannedNamespaces );
4791         }
4792
4793         /**
4794          * Returns the raw sort key to be used for categories, with the specified
4795          * prefix.  This will be fed to Collation::getSortKey() to get a
4796          * binary sortkey that can be used for actual sorting.
4797          *
4798          * @param string $prefix The prefix to be used, specified using
4799          *   {{defaultsort:}} or like [[Category:Foo|prefix]].  Empty for no
4800          *   prefix.
4801          * @return string
4802          */
4803         public function getCategorySortkey( $prefix = '' ) {
4804                 $unprefixed = $this->getText();
4805
4806                 // Anything that uses this hook should only depend
4807                 // on the Title object passed in, and should probably
4808                 // tell the users to run updateCollations.php --force
4809                 // in order to re-sort existing category relations.
4810                 Hooks::run( 'GetDefaultSortkey', [ $this, &$unprefixed ] );
4811                 if ( $prefix !== '' ) {
4812                         # Separate with a line feed, so the unprefixed part is only used as
4813                         # a tiebreaker when two pages have the exact same prefix.
4814                         # In UCA, tab is the only character that can sort above LF
4815                         # so we strip both of them from the original prefix.
4816                         $prefix = strtr( $prefix, "\n\t", '  ' );
4817                         return "$prefix\n$unprefixed";
4818                 }
4819                 return $unprefixed;
4820         }
4821
4822         /**
4823          * Returns the page language code saved in the database, if $wgPageLanguageUseDB is set
4824          * to true in LocalSettings.php, otherwise returns false. If there is no language saved in
4825          * the db, it will return NULL.
4826          *
4827          * @return string|null|bool
4828          */
4829         private function getDbPageLanguageCode() {
4830                 global $wgPageLanguageUseDB;
4831
4832                 // check, if the page language could be saved in the database, and if so and
4833                 // the value is not requested already, lookup the page language using LinkCache
4834                 if ( $wgPageLanguageUseDB && $this->mDbPageLanguage === false ) {
4835                         $linkCache = LinkCache::singleton();
4836                         $linkCache->addLinkObj( $this );
4837                         $this->mDbPageLanguage = $linkCache->getGoodLinkFieldObj( $this, 'lang' );
4838                 }
4839
4840                 return $this->mDbPageLanguage;
4841         }
4842
4843         /**
4844          * Get the language in which the content of this page is written in
4845          * wikitext. Defaults to $wgContLang, but in certain cases it can be
4846          * e.g. $wgLang (such as special pages, which are in the user language).
4847          *
4848          * @since 1.18
4849          * @return Language
4850          */
4851         public function getPageLanguage() {
4852                 global $wgLang, $wgLanguageCode;
4853                 if ( $this->isSpecialPage() ) {
4854                         // special pages are in the user language
4855                         return $wgLang;
4856                 }
4857
4858                 // Checking if DB language is set
4859                 $dbPageLanguage = $this->getDbPageLanguageCode();
4860                 if ( $dbPageLanguage ) {
4861                         return wfGetLangObj( $dbPageLanguage );
4862                 }
4863
4864                 if ( !$this->mPageLanguage || $this->mPageLanguage[1] !== $wgLanguageCode ) {
4865                         // Note that this may depend on user settings, so the cache should
4866                         // be only per-request.
4867                         // NOTE: ContentHandler::getPageLanguage() may need to load the
4868                         // content to determine the page language!
4869                         // Checking $wgLanguageCode hasn't changed for the benefit of unit
4870                         // tests.
4871                         $contentHandler = ContentHandler::getForTitle( $this );
4872                         $langObj = $contentHandler->getPageLanguage( $this );
4873                         $this->mPageLanguage = [ $langObj->getCode(), $wgLanguageCode ];
4874                 } else {
4875                         $langObj = wfGetLangObj( $this->mPageLanguage[0] );
4876                 }
4877
4878                 return $langObj;
4879         }
4880
4881         /**
4882          * Get the language in which the content of this page is written when
4883          * viewed by user. Defaults to $wgContLang, but in certain cases it can be
4884          * e.g. $wgLang (such as special pages, which are in the user language).
4885          *
4886          * @since 1.20
4887          * @return Language
4888          */
4889         public function getPageViewLanguage() {
4890                 global $wgLang;
4891
4892                 if ( $this->isSpecialPage() ) {
4893                         // If the user chooses a variant, the content is actually
4894                         // in a language whose code is the variant code.
4895                         $variant = $wgLang->getPreferredVariant();
4896                         if ( $wgLang->getCode() !== $variant ) {
4897                                 return Language::factory( $variant );
4898                         }
4899
4900                         return $wgLang;
4901                 }
4902
4903                 // Checking if DB language is set
4904                 $dbPageLanguage = $this->getDbPageLanguageCode();
4905                 if ( $dbPageLanguage ) {
4906                         $pageLang = wfGetLangObj( $dbPageLanguage );
4907                         $variant = $pageLang->getPreferredVariant();
4908                         if ( $pageLang->getCode() !== $variant ) {
4909                                 $pageLang = Language::factory( $variant );
4910                         }
4911
4912                         return $pageLang;
4913                 }
4914
4915                 // @note Can't be cached persistently, depends on user settings.
4916                 // @note ContentHandler::getPageViewLanguage() may need to load the
4917                 //   content to determine the page language!
4918                 $contentHandler = ContentHandler::getForTitle( $this );
4919                 $pageLang = $contentHandler->getPageViewLanguage( $this );
4920                 return $pageLang;
4921         }
4922
4923         /**
4924          * Get a list of rendered edit notices for this page.
4925          *
4926          * Array is keyed by the original message key, and values are rendered using parseAsBlock, so
4927          * they will already be wrapped in paragraphs.
4928          *
4929          * @since 1.21
4930          * @param int $oldid Revision ID that's being edited
4931          * @return array
4932          */
4933         public function getEditNotices( $oldid = 0 ) {
4934                 $notices = [];
4935
4936                 // Optional notice for the entire namespace
4937                 $editnotice_ns = 'editnotice-' . $this->getNamespace();
4938                 $msg = wfMessage( $editnotice_ns );
4939                 if ( $msg->exists() ) {
4940                         $html = $msg->parseAsBlock();
4941                         // Edit notices may have complex logic, but output nothing (T91715)
4942                         if ( trim( $html ) !== '' ) {
4943                                 $notices[$editnotice_ns] = Html::rawElement(
4944                                         'div',
4945                                         [ 'class' => [
4946                                                 'mw-editnotice',
4947                                                 'mw-editnotice-namespace',
4948                                                 Sanitizer::escapeClass( "mw-$editnotice_ns" )
4949                                         ] ],
4950                                         $html
4951                                 );
4952                         }
4953                 }
4954
4955                 if ( MWNamespace::hasSubpages( $this->getNamespace() ) ) {
4956                         // Optional notice for page itself and any parent page
4957                         $parts = explode( '/', $this->getDBkey() );
4958                         $editnotice_base = $editnotice_ns;
4959                         while ( count( $parts ) > 0 ) {
4960                                 $editnotice_base .= '-' . array_shift( $parts );
4961                                 $msg = wfMessage( $editnotice_base );
4962                                 if ( $msg->exists() ) {
4963                                         $html = $msg->parseAsBlock();
4964                                         if ( trim( $html ) !== '' ) {
4965                                                 $notices[$editnotice_base] = Html::rawElement(
4966                                                         'div',
4967                                                         [ 'class' => [
4968                                                                 'mw-editnotice',
4969                                                                 'mw-editnotice-base',
4970                                                                 Sanitizer::escapeClass( "mw-$editnotice_base" )
4971                                                         ] ],
4972                                                         $html
4973                                                 );
4974                                         }
4975                                 }
4976                         }
4977                 } else {
4978                         // Even if there are no subpages in namespace, we still don't want "/" in MediaWiki message keys
4979                         $editnoticeText = $editnotice_ns . '-' . strtr( $this->getDBkey(), '/', '-' );
4980                         $msg = wfMessage( $editnoticeText );
4981                         if ( $msg->exists() ) {
4982                                 $html = $msg->parseAsBlock();
4983                                 if ( trim( $html ) !== '' ) {
4984                                         $notices[$editnoticeText] = Html::rawElement(
4985                                                 'div',
4986                                                 [ 'class' => [
4987                                                         'mw-editnotice',
4988                                                         'mw-editnotice-page',
4989                                                         Sanitizer::escapeClass( "mw-$editnoticeText" )
4990                                                 ] ],
4991                                                 $html
4992                                         );
4993                                 }
4994                         }
4995                 }
4996
4997                 Hooks::run( 'TitleGetEditNotices', [ $this, $oldid, &$notices ] );
4998                 return $notices;
4999         }
5000
5001         /**
5002          * @return array
5003          */
5004         public function __sleep() {
5005                 return [
5006                         'mNamespace',
5007                         'mDbkeyform',
5008                         'mFragment',
5009                         'mInterwiki',
5010                         'mLocalInterwiki',
5011                         'mUserCaseDBKey',
5012                         'mDefaultNamespace',
5013                 ];
5014         }
5015
5016         public function __wakeup() {
5017                 $this->mArticleID = ( $this->mNamespace >= 0 ) ? -1 : 0;
5018                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
5019                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
5020         }
5021
5022 }