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