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                 $p = '';
1423                 if ( $this->isExternal() ) {
1424                         $p = $this->mInterwiki . ':';
1425                 }
1426
1427                 if ( 0 != $this->mNamespace ) {
1428                         $p .= $this->getNsText() . ':';
1429                 }
1430                 return $p . $name;
1431         }
1432
1433         /**
1434          * Get the prefixed database key form
1435          *
1436          * @return string The prefixed title, with underscores and
1437          *  any interwiki and namespace prefixes
1438          */
1439         public function getPrefixedDBkey() {
1440                 $s = $this->prefix( $this->mDbkeyform );
1441                 $s = strtr( $s, ' ', '_' );
1442                 return $s;
1443         }
1444
1445         /**
1446          * Get the prefixed title with spaces.
1447          * This is the form usually used for display
1448          *
1449          * @return string The prefixed title, with spaces
1450          */
1451         public function getPrefixedText() {
1452                 if ( $this->mPrefixedText === null ) {
1453                         $s = $this->prefix( $this->mTextform );
1454                         $s = strtr( $s, '_', ' ' );
1455                         $this->mPrefixedText = $s;
1456                 }
1457                 return $this->mPrefixedText;
1458         }
1459
1460         /**
1461          * Return a string representation of this title
1462          *
1463          * @return string Representation of this title
1464          */
1465         public function __toString() {
1466                 return $this->getPrefixedText();
1467         }
1468
1469         /**
1470          * Get the prefixed title with spaces, plus any fragment
1471          * (part beginning with '#')
1472          *
1473          * @return string The prefixed title, with spaces and the fragment, including '#'
1474          */
1475         public function getFullText() {
1476                 $text = $this->getPrefixedText();
1477                 if ( $this->hasFragment() ) {
1478                         $text .= '#' . $this->getFragment();
1479                 }
1480                 return $text;
1481         }
1482
1483         /**
1484          * Get the root page name text without a namespace, i.e. the leftmost part before any slashes
1485          *
1486          * @par Example:
1487          * @code
1488          * Title::newFromText('User:Foo/Bar/Baz')->getRootText();
1489          * # returns: 'Foo'
1490          * @endcode
1491          *
1492          * @return string Root name
1493          * @since 1.20
1494          */
1495         public function getRootText() {
1496                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1497                         return $this->getText();
1498                 }
1499
1500                 return strtok( $this->getText(), '/' );
1501         }
1502
1503         /**
1504          * Get the root page name title, i.e. the leftmost part before any slashes
1505          *
1506          * @par Example:
1507          * @code
1508          * Title::newFromText('User:Foo/Bar/Baz')->getRootTitle();
1509          * # returns: Title{User:Foo}
1510          * @endcode
1511          *
1512          * @return Title Root title
1513          * @since 1.20
1514          */
1515         public function getRootTitle() {
1516                 return Title::makeTitle( $this->getNamespace(), $this->getRootText() );
1517         }
1518
1519         /**
1520          * Get the base page name without a namespace, i.e. the part before the subpage name
1521          *
1522          * @par Example:
1523          * @code
1524          * Title::newFromText('User:Foo/Bar/Baz')->getBaseText();
1525          * # returns: 'Foo/Bar'
1526          * @endcode
1527          *
1528          * @return string Base name
1529          */
1530         public function getBaseText() {
1531                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1532                         return $this->getText();
1533                 }
1534
1535                 $parts = explode( '/', $this->getText() );
1536                 # Don't discard the real title if there's no subpage involved
1537                 if ( count( $parts ) > 1 ) {
1538                         unset( $parts[count( $parts ) - 1] );
1539                 }
1540                 return implode( '/', $parts );
1541         }
1542
1543         /**
1544          * Get the base page name title, i.e. the part before the subpage name
1545          *
1546          * @par Example:
1547          * @code
1548          * Title::newFromText('User:Foo/Bar/Baz')->getBaseTitle();
1549          * # returns: Title{User:Foo/Bar}
1550          * @endcode
1551          *
1552          * @return Title Base title
1553          * @since 1.20
1554          */
1555         public function getBaseTitle() {
1556                 return Title::makeTitle( $this->getNamespace(), $this->getBaseText() );
1557         }
1558
1559         /**
1560          * Get the lowest-level subpage name, i.e. the rightmost part after any slashes
1561          *
1562          * @par Example:
1563          * @code
1564          * Title::newFromText('User:Foo/Bar/Baz')->getSubpageText();
1565          * # returns: "Baz"
1566          * @endcode
1567          *
1568          * @return string Subpage name
1569          */
1570         public function getSubpageText() {
1571                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1572                         return $this->mTextform;
1573                 }
1574                 $parts = explode( '/', $this->mTextform );
1575                 return $parts[count( $parts ) - 1];
1576         }
1577
1578         /**
1579          * Get the title for a subpage of the current page
1580          *
1581          * @par Example:
1582          * @code
1583          * Title::newFromText('User:Foo/Bar/Baz')->getSubpage("Asdf");
1584          * # returns: Title{User:Foo/Bar/Baz/Asdf}
1585          * @endcode
1586          *
1587          * @param string $text The subpage name to add to the title
1588          * @return Title Subpage title
1589          * @since 1.20
1590          */
1591         public function getSubpage( $text ) {
1592                 return Title::makeTitleSafe( $this->getNamespace(), $this->getText() . '/' . $text );
1593         }
1594
1595         /**
1596          * Get a URL-encoded form of the subpage text
1597          *
1598          * @return string URL-encoded subpage name
1599          */
1600         public function getSubpageUrlForm() {
1601                 $text = $this->getSubpageText();
1602                 $text = wfUrlencode( strtr( $text, ' ', '_' ) );
1603                 return $text;
1604         }
1605
1606         /**
1607          * Get a URL-encoded title (not an actual URL) including interwiki
1608          *
1609          * @return string The URL-encoded form
1610          */
1611         public function getPrefixedURL() {
1612                 $s = $this->prefix( $this->mDbkeyform );
1613                 $s = wfUrlencode( strtr( $s, ' ', '_' ) );
1614                 return $s;
1615         }
1616
1617         /**
1618          * Helper to fix up the get{Canonical,Full,Link,Local,Internal}URL args
1619          * get{Canonical,Full,Link,Local,Internal}URL methods accepted an optional
1620          * second argument named variant. This was deprecated in favor
1621          * of passing an array of option with a "variant" key
1622          * Once $query2 is removed for good, this helper can be dropped
1623          * and the wfArrayToCgi moved to getLocalURL();
1624          *
1625          * @since 1.19 (r105919)
1626          * @param array|string $query
1627          * @param string|string[]|bool $query2
1628          * @return string
1629          */
1630         private static function fixUrlQueryArgs( $query, $query2 = false ) {
1631                 if ( $query2 !== false ) {
1632                         wfDeprecated( "Title::get{Canonical,Full,Link,Local,Internal}URL " .
1633                                 "method called with a second parameter is deprecated. Add your " .
1634                                 "parameter to an array passed as the first parameter.", "1.19" );
1635                 }
1636                 if ( is_array( $query ) ) {
1637                         $query = wfArrayToCgi( $query );
1638                 }
1639                 if ( $query2 ) {
1640                         if ( is_string( $query2 ) ) {
1641                                 // $query2 is a string, we will consider this to be
1642                                 // a deprecated $variant argument and add it to the query
1643                                 $query2 = wfArrayToCgi( [ 'variant' => $query2 ] );
1644                         } else {
1645                                 $query2 = wfArrayToCgi( $query2 );
1646                         }
1647                         // If we have $query content add a & to it first
1648                         if ( $query ) {
1649                                 $query .= '&';
1650                         }
1651                         // Now append the queries together
1652                         $query .= $query2;
1653                 }
1654                 return $query;
1655         }
1656
1657         /**
1658          * Get a real URL referring to this title, with interwiki link and
1659          * fragment
1660          *
1661          * @see self::getLocalURL for the arguments.
1662          * @see wfExpandUrl
1663          * @param string|string[] $query
1664          * @param string|string[]|bool $query2
1665          * @param string $proto Protocol type to use in URL
1666          * @return string The URL
1667          */
1668         public function getFullURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1669                 $query = self::fixUrlQueryArgs( $query, $query2 );
1670
1671                 # Hand off all the decisions on urls to getLocalURL
1672                 $url = $this->getLocalURL( $query );
1673
1674                 # Expand the url to make it a full url. Note that getLocalURL has the
1675                 # potential to output full urls for a variety of reasons, so we use
1676                 # wfExpandUrl instead of simply prepending $wgServer
1677                 $url = wfExpandUrl( $url, $proto );
1678
1679                 # Finally, add the fragment.
1680                 $url .= $this->getFragmentForURL();
1681                 // Avoid PHP 7.1 warning from passing $this by reference
1682                 $titleRef = $this;
1683                 Hooks::run( 'GetFullURL', [ &$titleRef, &$url, $query ] );
1684                 return $url;
1685         }
1686
1687         /**
1688          * Get a url appropriate for making redirects based on an untrusted url arg
1689          *
1690          * This is basically the same as getFullUrl(), but in the case of external
1691          * interwikis, we send the user to a landing page, to prevent possible
1692          * phishing attacks and the like.
1693          *
1694          * @note Uses current protocol by default, since technically relative urls
1695          *   aren't allowed in redirects per HTTP spec, so this is not suitable for
1696          *   places where the url gets cached, as might pollute between
1697          *   https and non-https users.
1698          * @see self::getLocalURL for the arguments.
1699          * @param array|string $query
1700          * @param string $proto Protocol type to use in URL
1701          * @return String. A url suitable to use in an HTTP location header.
1702          */
1703         public function getFullUrlForRedirect( $query = '', $proto = PROTO_CURRENT ) {
1704                 $target = $this;
1705                 if ( $this->isExternal() ) {
1706                         $target = SpecialPage::getTitleFor(
1707                                 'GoToInterwiki',
1708                                 $this->getPrefixedDBKey()
1709                         );
1710                 }
1711                 return $target->getFullUrl( $query, false, $proto );
1712         }
1713
1714         /**
1715          * Get a URL with no fragment or server name (relative URL) from a Title object.
1716          * If this page is generated with action=render, however,
1717          * $wgServer is prepended to make an absolute URL.
1718          *
1719          * @see self::getFullURL to always get an absolute URL.
1720          * @see self::getLinkURL to always get a URL that's the simplest URL that will be
1721          *  valid to link, locally, to the current Title.
1722          * @see self::newFromText to produce a Title object.
1723          *
1724          * @param string|string[] $query An optional query string,
1725          *   not used for interwiki links. Can be specified as an associative array as well,
1726          *   e.g., array( 'action' => 'edit' ) (keys and values will be URL-escaped).
1727          *   Some query patterns will trigger various shorturl path replacements.
1728          * @param string|string[]|bool $query2 An optional secondary query array. This one MUST
1729          *   be an array. If a string is passed it will be interpreted as a deprecated
1730          *   variant argument and urlencoded into a variant= argument.
1731          *   This second query argument will be added to the $query
1732          *   The second parameter is deprecated since 1.19. Pass it as a key,value
1733          *   pair in the first parameter array instead.
1734          *
1735          * @return string String of the URL.
1736          */
1737         public function getLocalURL( $query = '', $query2 = false ) {
1738                 global $wgArticlePath, $wgScript, $wgServer, $wgRequest;
1739
1740                 $query = self::fixUrlQueryArgs( $query, $query2 );
1741
1742                 $interwiki = self::getInterwikiLookup()->fetch( $this->mInterwiki );
1743                 if ( $interwiki ) {
1744                         $namespace = $this->getNsText();
1745                         if ( $namespace != '' ) {
1746                                 # Can this actually happen? Interwikis shouldn't be parsed.
1747                                 # Yes! It can in interwiki transclusion. But... it probably shouldn't.
1748                                 $namespace .= ':';
1749                         }
1750                         $url = $interwiki->getURL( $namespace . $this->getDBkey() );
1751                         $url = wfAppendQuery( $url, $query );
1752                 } else {
1753                         $dbkey = wfUrlencode( $this->getPrefixedDBkey() );
1754                         if ( $query == '' ) {
1755                                 $url = str_replace( '$1', $dbkey, $wgArticlePath );
1756                                 // Avoid PHP 7.1 warning from passing $this by reference
1757                                 $titleRef = $this;
1758                                 Hooks::run( 'GetLocalURL::Article', [ &$titleRef, &$url ] );
1759                         } else {
1760                                 global $wgVariantArticlePath, $wgActionPaths, $wgContLang;
1761                                 $url = false;
1762                                 $matches = [];
1763
1764                                 if ( !empty( $wgActionPaths )
1765                                         && preg_match( '/^(.*&|)action=([^&]*)(&(.*)|)$/', $query, $matches )
1766                                 ) {
1767                                         $action = urldecode( $matches[2] );
1768                                         if ( isset( $wgActionPaths[$action] ) ) {
1769                                                 $query = $matches[1];
1770                                                 if ( isset( $matches[4] ) ) {
1771                                                         $query .= $matches[4];
1772                                                 }
1773                                                 $url = str_replace( '$1', $dbkey, $wgActionPaths[$action] );
1774                                                 if ( $query != '' ) {
1775                                                         $url = wfAppendQuery( $url, $query );
1776                                                 }
1777                                         }
1778                                 }
1779
1780                                 if ( $url === false
1781                                         && $wgVariantArticlePath
1782                                         && preg_match( '/^variant=([^&]*)$/', $query, $matches )
1783                                         && $this->getPageLanguage()->equals( $wgContLang )
1784                                         && $this->getPageLanguage()->hasVariants()
1785                                 ) {
1786                                         $variant = urldecode( $matches[1] );
1787                                         if ( $this->getPageLanguage()->hasVariant( $variant ) ) {
1788                                                 // Only do the variant replacement if the given variant is a valid
1789                                                 // variant for the page's language.
1790                                                 $url = str_replace( '$2', urlencode( $variant ), $wgVariantArticlePath );
1791                                                 $url = str_replace( '$1', $dbkey, $url );
1792                                         }
1793                                 }
1794
1795                                 if ( $url === false ) {
1796                                         if ( $query == '-' ) {
1797                                                 $query = '';
1798                                         }
1799                                         $url = "{$wgScript}?title={$dbkey}&{$query}";
1800                                 }
1801                         }
1802                         // Avoid PHP 7.1 warning from passing $this by reference
1803                         $titleRef = $this;
1804                         Hooks::run( 'GetLocalURL::Internal', [ &$titleRef, &$url, $query ] );
1805
1806                         // @todo FIXME: This causes breakage in various places when we
1807                         // actually expected a local URL and end up with dupe prefixes.
1808                         if ( $wgRequest->getVal( 'action' ) == 'render' ) {
1809                                 $url = $wgServer . $url;
1810                         }
1811                 }
1812                 // Avoid PHP 7.1 warning from passing $this by reference
1813                 $titleRef = $this;
1814                 Hooks::run( 'GetLocalURL', [ &$titleRef, &$url, $query ] );
1815                 return $url;
1816         }
1817
1818         /**
1819          * Get a URL that's the simplest URL that will be valid to link, locally,
1820          * to the current Title.  It includes the fragment, but does not include
1821          * the server unless action=render is used (or the link is external).  If
1822          * there's a fragment but the prefixed text is empty, we just return a link
1823          * to the fragment.
1824          *
1825          * The result obviously should not be URL-escaped, but does need to be
1826          * HTML-escaped if it's being output in HTML.
1827          *
1828          * @param string|string[] $query
1829          * @param bool $query2
1830          * @param string|int|bool $proto A PROTO_* constant on how the URL should be expanded,
1831          *                               or false (default) for no expansion
1832          * @see self::getLocalURL for the arguments.
1833          * @return string The URL
1834          */
1835         public function getLinkURL( $query = '', $query2 = false, $proto = false ) {
1836                 if ( $this->isExternal() || $proto !== false ) {
1837                         $ret = $this->getFullURL( $query, $query2, $proto );
1838                 } elseif ( $this->getPrefixedText() === '' && $this->hasFragment() ) {
1839                         $ret = $this->getFragmentForURL();
1840                 } else {
1841                         $ret = $this->getLocalURL( $query, $query2 ) . $this->getFragmentForURL();
1842                 }
1843                 return $ret;
1844         }
1845
1846         /**
1847          * Get the URL form for an internal link.
1848          * - Used in various CDN-related code, in case we have a different
1849          * internal hostname for the server from the exposed one.
1850          *
1851          * This uses $wgInternalServer to qualify the path, or $wgServer
1852          * if $wgInternalServer is not set. If the server variable used is
1853          * protocol-relative, the URL will be expanded to http://
1854          *
1855          * @see self::getLocalURL for the arguments.
1856          * @return string The URL
1857          */
1858         public function getInternalURL( $query = '', $query2 = false ) {
1859                 global $wgInternalServer, $wgServer;
1860                 $query = self::fixUrlQueryArgs( $query, $query2 );
1861                 $server = $wgInternalServer !== false ? $wgInternalServer : $wgServer;
1862                 $url = wfExpandUrl( $server . $this->getLocalURL( $query ), PROTO_HTTP );
1863                 // Avoid PHP 7.1 warning from passing $this by reference
1864                 $titleRef = $this;
1865                 Hooks::run( 'GetInternalURL', [ &$titleRef, &$url, $query ] );
1866                 return $url;
1867         }
1868
1869         /**
1870          * Get the URL for a canonical link, for use in things like IRC and
1871          * e-mail notifications. Uses $wgCanonicalServer and the
1872          * GetCanonicalURL hook.
1873          *
1874          * NOTE: Unlike getInternalURL(), the canonical URL includes the fragment
1875          *
1876          * @see self::getLocalURL for the arguments.
1877          * @return string The URL
1878          * @since 1.18
1879          */
1880         public function getCanonicalURL( $query = '', $query2 = false ) {
1881                 $query = self::fixUrlQueryArgs( $query, $query2 );
1882                 $url = wfExpandUrl( $this->getLocalURL( $query ) . $this->getFragmentForURL(), PROTO_CANONICAL );
1883                 // Avoid PHP 7.1 warning from passing $this by reference
1884                 $titleRef = $this;
1885                 Hooks::run( 'GetCanonicalURL', [ &$titleRef, &$url, $query ] );
1886                 return $url;
1887         }
1888
1889         /**
1890          * Get the edit URL for this Title
1891          *
1892          * @return string The URL, or a null string if this is an interwiki link
1893          */
1894         public function getEditURL() {
1895                 if ( $this->isExternal() ) {
1896                         return '';
1897                 }
1898                 $s = $this->getLocalURL( 'action=edit' );
1899
1900                 return $s;
1901         }
1902
1903         /**
1904          * Can $user perform $action on this page?
1905          * This skips potentially expensive cascading permission checks
1906          * as well as avoids expensive error formatting
1907          *
1908          * Suitable for use for nonessential UI controls in common cases, but
1909          * _not_ for functional access control.
1910          *
1911          * May provide false positives, but should never provide a false negative.
1912          *
1913          * @param string $action Action that permission needs to be checked for
1914          * @param User $user User to check (since 1.19); $wgUser will be used if not provided.
1915          * @return bool
1916          */
1917         public function quickUserCan( $action, $user = null ) {
1918                 return $this->userCan( $action, $user, false );
1919         }
1920
1921         /**
1922          * Can $user perform $action on this page?
1923          *
1924          * @param string $action Action that permission needs to be checked for
1925          * @param User $user User to check (since 1.19); $wgUser will be used if not
1926          *   provided.
1927          * @param string $rigor Same format as Title::getUserPermissionsErrors()
1928          * @return bool
1929          */
1930         public function userCan( $action, $user = null, $rigor = 'secure' ) {
1931                 if ( !$user instanceof User ) {
1932                         global $wgUser;
1933                         $user = $wgUser;
1934                 }
1935
1936                 return !count( $this->getUserPermissionsErrorsInternal( $action, $user, $rigor, true ) );
1937         }
1938
1939         /**
1940          * Can $user perform $action on this page?
1941          *
1942          * @todo FIXME: This *does not* check throttles (User::pingLimiter()).
1943          *
1944          * @param string $action Action that permission needs to be checked for
1945          * @param User $user User to check
1946          * @param string $rigor One of (quick,full,secure)
1947          *   - quick  : does cheap permission checks from replica DBs (usable for GUI creation)
1948          *   - full   : does cheap and expensive checks possibly from a replica DB
1949          *   - secure : does cheap and expensive checks, using the master as needed
1950          * @param array $ignoreErrors Array of Strings Set this to a list of message keys
1951          *   whose corresponding errors may be ignored.
1952          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
1953          */
1954         public function getUserPermissionsErrors(
1955                 $action, $user, $rigor = 'secure', $ignoreErrors = []
1956         ) {
1957                 $errors = $this->getUserPermissionsErrorsInternal( $action, $user, $rigor );
1958
1959                 // Remove the errors being ignored.
1960                 foreach ( $errors as $index => $error ) {
1961                         $errKey = is_array( $error ) ? $error[0] : $error;
1962
1963                         if ( in_array( $errKey, $ignoreErrors ) ) {
1964                                 unset( $errors[$index] );
1965                         }
1966                         if ( $errKey instanceof MessageSpecifier && in_array( $errKey->getKey(), $ignoreErrors ) ) {
1967                                 unset( $errors[$index] );
1968                         }
1969                 }
1970
1971                 return $errors;
1972         }
1973
1974         /**
1975          * Permissions checks that fail most often, and which are easiest to test.
1976          *
1977          * @param string $action The action to check
1978          * @param User $user User to check
1979          * @param array $errors List of current errors
1980          * @param string $rigor Same format as Title::getUserPermissionsErrors()
1981          * @param bool $short Short circuit on first error
1982          *
1983          * @return array List of errors
1984          */
1985         private function checkQuickPermissions( $action, $user, $errors, $rigor, $short ) {
1986                 if ( !Hooks::run( 'TitleQuickPermissions',
1987                         [ $this, $user, $action, &$errors, ( $rigor !== 'quick' ), $short ] )
1988                 ) {
1989                         return $errors;
1990                 }
1991
1992                 if ( $action == 'create' ) {
1993                         if (
1994                                 ( $this->isTalkPage() && !$user->isAllowed( 'createtalk' ) ) ||
1995                                 ( !$this->isTalkPage() && !$user->isAllowed( 'createpage' ) )
1996                         ) {
1997                                 $errors[] = $user->isAnon() ? [ 'nocreatetext' ] : [ 'nocreate-loggedin' ];
1998                         }
1999                 } elseif ( $action == 'move' ) {
2000                         if ( !$user->isAllowed( 'move-rootuserpages' )
2001                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
2002                                 // Show user page-specific message only if the user can move other pages
2003                                 $errors[] = [ 'cant-move-user-page' ];
2004                         }
2005
2006                         // Check if user is allowed to move files if it's a file
2007                         if ( $this->mNamespace == NS_FILE && !$user->isAllowed( 'movefile' ) ) {
2008                                 $errors[] = [ 'movenotallowedfile' ];
2009                         }
2010
2011                         // Check if user is allowed to move category pages if it's a category page
2012                         if ( $this->mNamespace == NS_CATEGORY && !$user->isAllowed( 'move-categorypages' ) ) {
2013                                 $errors[] = [ 'cant-move-category-page' ];
2014                         }
2015
2016                         if ( !$user->isAllowed( 'move' ) ) {
2017                                 // User can't move anything
2018                                 $userCanMove = User::groupHasPermission( 'user', 'move' );
2019                                 $autoconfirmedCanMove = User::groupHasPermission( 'autoconfirmed', 'move' );
2020                                 if ( $user->isAnon() && ( $userCanMove || $autoconfirmedCanMove ) ) {
2021                                         // custom message if logged-in users without any special rights can move
2022                                         $errors[] = [ 'movenologintext' ];
2023                                 } else {
2024                                         $errors[] = [ 'movenotallowed' ];
2025                                 }
2026                         }
2027                 } elseif ( $action == 'move-target' ) {
2028                         if ( !$user->isAllowed( 'move' ) ) {
2029                                 // User can't move anything
2030                                 $errors[] = [ 'movenotallowed' ];
2031                         } elseif ( !$user->isAllowed( 'move-rootuserpages' )
2032                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
2033                                 // Show user page-specific message only if the user can move other pages
2034                                 $errors[] = [ 'cant-move-to-user-page' ];
2035                         } elseif ( !$user->isAllowed( 'move-categorypages' )
2036                                         && $this->mNamespace == NS_CATEGORY ) {
2037                                 // Show category page-specific message only if the user can move other pages
2038                                 $errors[] = [ 'cant-move-to-category-page' ];
2039                         }
2040                 } elseif ( !$user->isAllowed( $action ) ) {
2041                         $errors[] = $this->missingPermissionError( $action, $short );
2042                 }
2043
2044                 return $errors;
2045         }
2046
2047         /**
2048          * Add the resulting error code to the errors array
2049          *
2050          * @param array $errors List of current errors
2051          * @param array $result Result of errors
2052          *
2053          * @return array List of errors
2054          */
2055         private function resultToError( $errors, $result ) {
2056                 if ( is_array( $result ) && count( $result ) && !is_array( $result[0] ) ) {
2057                         // A single array representing an error
2058                         $errors[] = $result;
2059                 } elseif ( is_array( $result ) && is_array( $result[0] ) ) {
2060                         // A nested array representing multiple errors
2061                         $errors = array_merge( $errors, $result );
2062                 } elseif ( $result !== '' && is_string( $result ) ) {
2063                         // A string representing a message-id
2064                         $errors[] = [ $result ];
2065                 } elseif ( $result instanceof MessageSpecifier ) {
2066                         // A message specifier representing an error
2067                         $errors[] = [ $result ];
2068                 } elseif ( $result === false ) {
2069                         // a generic "We don't want them to do that"
2070                         $errors[] = [ 'badaccess-group0' ];
2071                 }
2072                 return $errors;
2073         }
2074
2075         /**
2076          * Check various permission hooks
2077          *
2078          * @param string $action The action to check
2079          * @param User $user User to check
2080          * @param array $errors List of current errors
2081          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2082          * @param bool $short Short circuit on first error
2083          *
2084          * @return array List of errors
2085          */
2086         private function checkPermissionHooks( $action, $user, $errors, $rigor, $short ) {
2087                 // Use getUserPermissionsErrors instead
2088                 $result = '';
2089                 // Avoid PHP 7.1 warning from passing $this by reference
2090                 $titleRef = $this;
2091                 if ( !Hooks::run( 'userCan', [ &$titleRef, &$user, $action, &$result ] ) ) {
2092                         return $result ? [] : [ [ 'badaccess-group0' ] ];
2093                 }
2094                 // Check getUserPermissionsErrors hook
2095                 // Avoid PHP 7.1 warning from passing $this by reference
2096                 $titleRef = $this;
2097                 if ( !Hooks::run( 'getUserPermissionsErrors', [ &$titleRef, &$user, $action, &$result ] ) ) {
2098                         $errors = $this->resultToError( $errors, $result );
2099                 }
2100                 // Check getUserPermissionsErrorsExpensive hook
2101                 if (
2102                         $rigor !== 'quick'
2103                         && !( $short && count( $errors ) > 0 )
2104                         && !Hooks::run( 'getUserPermissionsErrorsExpensive', [ &$titleRef, &$user, $action, &$result ] )
2105                 ) {
2106                         $errors = $this->resultToError( $errors, $result );
2107                 }
2108
2109                 return $errors;
2110         }
2111
2112         /**
2113          * Check permissions on special pages & namespaces
2114          *
2115          * @param string $action The action to check
2116          * @param User $user User to check
2117          * @param array $errors List of current errors
2118          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2119          * @param bool $short Short circuit on first error
2120          *
2121          * @return array List of errors
2122          */
2123         private function checkSpecialsAndNSPermissions( $action, $user, $errors, $rigor, $short ) {
2124                 # Only 'createaccount' can be performed on special pages,
2125                 # which don't actually exist in the DB.
2126                 if ( NS_SPECIAL == $this->mNamespace && $action !== 'createaccount' ) {
2127                         $errors[] = [ 'ns-specialprotected' ];
2128                 }
2129
2130                 # Check $wgNamespaceProtection for restricted namespaces
2131                 if ( $this->isNamespaceProtected( $user ) ) {
2132                         $ns = $this->mNamespace == NS_MAIN ?
2133                                 wfMessage( 'nstab-main' )->text() : $this->getNsText();
2134                         $errors[] = $this->mNamespace == NS_MEDIAWIKI ?
2135                                 [ 'protectedinterface', $action ] : [ 'namespaceprotected', $ns, $action ];
2136                 }
2137
2138                 return $errors;
2139         }
2140
2141         /**
2142          * Check CSS/JS sub-page permissions
2143          *
2144          * @param string $action The action to check
2145          * @param User $user User to check
2146          * @param array $errors List of current errors
2147          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2148          * @param bool $short Short circuit on first error
2149          *
2150          * @return array List of errors
2151          */
2152         private function checkCSSandJSPermissions( $action, $user, $errors, $rigor, $short ) {
2153                 # Protect css/js subpages of user pages
2154                 # XXX: this might be better using restrictions
2155                 # XXX: right 'editusercssjs' is deprecated, for backward compatibility only
2156                 if ( $action != 'patrol' && !$user->isAllowed( 'editusercssjs' ) ) {
2157                         if ( preg_match( '/^' . preg_quote( $user->getName(), '/' ) . '\//', $this->mTextform ) ) {
2158                                 if ( $this->isCssSubpage() && !$user->isAllowedAny( 'editmyusercss', 'editusercss' ) ) {
2159                                         $errors[] = [ 'mycustomcssprotected', $action ];
2160                                 } elseif ( $this->isJsSubpage() && !$user->isAllowedAny( 'editmyuserjs', 'edituserjs' ) ) {
2161                                         $errors[] = [ 'mycustomjsprotected', $action ];
2162                                 }
2163                         } else {
2164                                 if ( $this->isCssSubpage() && !$user->isAllowed( 'editusercss' ) ) {
2165                                         $errors[] = [ 'customcssprotected', $action ];
2166                                 } elseif ( $this->isJsSubpage() && !$user->isAllowed( 'edituserjs' ) ) {
2167                                         $errors[] = [ 'customjsprotected', $action ];
2168                                 }
2169                         }
2170                 }
2171
2172                 return $errors;
2173         }
2174
2175         /**
2176          * Check against page_restrictions table requirements on this
2177          * page. The user must possess all required rights for this
2178          * action.
2179          *
2180          * @param string $action The action to check
2181          * @param User $user User to check
2182          * @param array $errors List of current errors
2183          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2184          * @param bool $short Short circuit on first error
2185          *
2186          * @return array List of errors
2187          */
2188         private function checkPageRestrictions( $action, $user, $errors, $rigor, $short ) {
2189                 foreach ( $this->getRestrictions( $action ) as $right ) {
2190                         // Backwards compatibility, rewrite sysop -> editprotected
2191                         if ( $right == 'sysop' ) {
2192                                 $right = 'editprotected';
2193                         }
2194                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2195                         if ( $right == 'autoconfirmed' ) {
2196                                 $right = 'editsemiprotected';
2197                         }
2198                         if ( $right == '' ) {
2199                                 continue;
2200                         }
2201                         if ( !$user->isAllowed( $right ) ) {
2202                                 $errors[] = [ 'protectedpagetext', $right, $action ];
2203                         } elseif ( $this->mCascadeRestriction && !$user->isAllowed( 'protect' ) ) {
2204                                 $errors[] = [ 'protectedpagetext', 'protect', $action ];
2205                         }
2206                 }
2207
2208                 return $errors;
2209         }
2210
2211         /**
2212          * Check restrictions on cascading pages.
2213          *
2214          * @param string $action The action to check
2215          * @param User $user User to check
2216          * @param array $errors List of current errors
2217          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2218          * @param bool $short Short circuit on first error
2219          *
2220          * @return array List of errors
2221          */
2222         private function checkCascadingSourcesRestrictions( $action, $user, $errors, $rigor, $short ) {
2223                 if ( $rigor !== 'quick' && !$this->isCssJsSubpage() ) {
2224                         # We /could/ use the protection level on the source page, but it's
2225                         # fairly ugly as we have to establish a precedence hierarchy for pages
2226                         # included by multiple cascade-protected pages. So just restrict
2227                         # it to people with 'protect' permission, as they could remove the
2228                         # protection anyway.
2229                         list( $cascadingSources, $restrictions ) = $this->getCascadeProtectionSources();
2230                         # Cascading protection depends on more than this page...
2231                         # Several cascading protected pages may include this page...
2232                         # Check each cascading level
2233                         # This is only for protection restrictions, not for all actions
2234                         if ( isset( $restrictions[$action] ) ) {
2235                                 foreach ( $restrictions[$action] as $right ) {
2236                                         // Backwards compatibility, rewrite sysop -> editprotected
2237                                         if ( $right == 'sysop' ) {
2238                                                 $right = 'editprotected';
2239                                         }
2240                                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2241                                         if ( $right == 'autoconfirmed' ) {
2242                                                 $right = 'editsemiprotected';
2243                                         }
2244                                         if ( $right != '' && !$user->isAllowedAll( 'protect', $right ) ) {
2245                                                 $pages = '';
2246                                                 foreach ( $cascadingSources as $page ) {
2247                                                         $pages .= '* [[:' . $page->getPrefixedText() . "]]\n";
2248                                                 }
2249                                                 $errors[] = [ 'cascadeprotected', count( $cascadingSources ), $pages, $action ];
2250                                         }
2251                                 }
2252                         }
2253                 }
2254
2255                 return $errors;
2256         }
2257
2258         /**
2259          * Check action permissions not already checked in checkQuickPermissions
2260          *
2261          * @param string $action The action to check
2262          * @param User $user User to check
2263          * @param array $errors List of current errors
2264          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2265          * @param bool $short Short circuit on first error
2266          *
2267          * @return array List of errors
2268          */
2269         private function checkActionPermissions( $action, $user, $errors, $rigor, $short ) {
2270                 global $wgDeleteRevisionsLimit, $wgLang;
2271
2272                 if ( $action == 'protect' ) {
2273                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit', $user, $rigor, true ) ) ) {
2274                                 // If they can't edit, they shouldn't protect.
2275                                 $errors[] = [ 'protect-cantedit' ];
2276                         }
2277                 } elseif ( $action == 'create' ) {
2278                         $title_protection = $this->getTitleProtection();
2279                         if ( $title_protection ) {
2280                                 if ( $title_protection['permission'] == ''
2281                                         || !$user->isAllowed( $title_protection['permission'] )
2282                                 ) {
2283                                         $errors[] = [
2284                                                 'titleprotected',
2285                                                 User::whoIs( $title_protection['user'] ),
2286                                                 $title_protection['reason']
2287                                         ];
2288                                 }
2289                         }
2290                 } elseif ( $action == 'move' ) {
2291                         // Check for immobile pages
2292                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2293                                 // Specific message for this case
2294                                 $errors[] = [ 'immobile-source-namespace', $this->getNsText() ];
2295                         } elseif ( !$this->isMovable() ) {
2296                                 // Less specific message for rarer cases
2297                                 $errors[] = [ 'immobile-source-page' ];
2298                         }
2299                 } elseif ( $action == 'move-target' ) {
2300                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2301                                 $errors[] = [ 'immobile-target-namespace', $this->getNsText() ];
2302                         } elseif ( !$this->isMovable() ) {
2303                                 $errors[] = [ 'immobile-target-page' ];
2304                         }
2305                 } elseif ( $action == 'delete' ) {
2306                         $tempErrors = $this->checkPageRestrictions( 'edit', $user, [], $rigor, true );
2307                         if ( !$tempErrors ) {
2308                                 $tempErrors = $this->checkCascadingSourcesRestrictions( 'edit',
2309                                         $user, $tempErrors, $rigor, true );
2310                         }
2311                         if ( $tempErrors ) {
2312                                 // If protection keeps them from editing, they shouldn't be able to delete.
2313                                 $errors[] = [ 'deleteprotected' ];
2314                         }
2315                         if ( $rigor !== 'quick' && $wgDeleteRevisionsLimit
2316                                 && !$this->userCan( 'bigdelete', $user ) && $this->isBigDeletion()
2317                         ) {
2318                                 $errors[] = [ 'delete-toobig', $wgLang->formatNum( $wgDeleteRevisionsLimit ) ];
2319                         }
2320                 } elseif ( $action === 'undelete' ) {
2321                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit', $user, $rigor, true ) ) ) {
2322                                 // Undeleting implies editing
2323                                 $errors[] = [ 'undelete-cantedit' ];
2324                         }
2325                         if ( !$this->exists()
2326                                 && count( $this->getUserPermissionsErrorsInternal( 'create', $user, $rigor, true ) )
2327                         ) {
2328                                 // Undeleting where nothing currently exists implies creating
2329                                 $errors[] = [ 'undelete-cantcreate' ];
2330                         }
2331                 }
2332                 return $errors;
2333         }
2334
2335         /**
2336          * Check that the user isn't blocked from editing.
2337          *
2338          * @param string $action The action to check
2339          * @param User $user User to check
2340          * @param array $errors List of current errors
2341          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2342          * @param bool $short Short circuit on first error
2343          *
2344          * @return array List of errors
2345          */
2346         private function checkUserBlock( $action, $user, $errors, $rigor, $short ) {
2347                 global $wgEmailConfirmToEdit, $wgBlockDisablesLogin;
2348                 // Account creation blocks handled at userlogin.
2349                 // Unblocking handled in SpecialUnblock
2350                 if ( $rigor === 'quick' || in_array( $action, [ 'createaccount', 'unblock' ] ) ) {
2351                         return $errors;
2352                 }
2353
2354                 // Optimize for a very common case
2355                 if ( $action === 'read' && !$wgBlockDisablesLogin ) {
2356                         return $errors;
2357                 }
2358
2359                 if ( $wgEmailConfirmToEdit && !$user->isEmailConfirmed() ) {
2360                         $errors[] = [ 'confirmedittext' ];
2361                 }
2362
2363                 $useSlave = ( $rigor !== 'secure' );
2364                 if ( ( $action == 'edit' || $action == 'create' )
2365                         && !$user->isBlockedFrom( $this, $useSlave )
2366                 ) {
2367                         // Don't block the user from editing their own talk page unless they've been
2368                         // explicitly blocked from that too.
2369                 } elseif ( $user->isBlocked() && $user->getBlock()->prevents( $action ) !== false ) {
2370                         // @todo FIXME: Pass the relevant context into this function.
2371                         $errors[] = $user->getBlock()->getPermissionsError( RequestContext::getMain() );
2372                 }
2373
2374                 return $errors;
2375         }
2376
2377         /**
2378          * Check that the user is allowed to read this page.
2379          *
2380          * @param string $action The action to check
2381          * @param User $user User to check
2382          * @param array $errors List of current errors
2383          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2384          * @param bool $short Short circuit on first error
2385          *
2386          * @return array List of errors
2387          */
2388         private function checkReadPermissions( $action, $user, $errors, $rigor, $short ) {
2389                 global $wgWhitelistRead, $wgWhitelistReadRegexp;
2390
2391                 $whitelisted = false;
2392                 if ( User::isEveryoneAllowed( 'read' ) ) {
2393                         # Shortcut for public wikis, allows skipping quite a bit of code
2394                         $whitelisted = true;
2395                 } elseif ( $user->isAllowed( 'read' ) ) {
2396                         # If the user is allowed to read pages, he is allowed to read all pages
2397                         $whitelisted = true;
2398                 } elseif ( $this->isSpecial( 'Userlogin' )
2399                         || $this->isSpecial( 'PasswordReset' )
2400                         || $this->isSpecial( 'Userlogout' )
2401                 ) {
2402                         # Always grant access to the login page.
2403                         # Even anons need to be able to log in.
2404                         $whitelisted = true;
2405                 } elseif ( is_array( $wgWhitelistRead ) && count( $wgWhitelistRead ) ) {
2406                         # Time to check the whitelist
2407                         # Only do these checks is there's something to check against
2408                         $name = $this->getPrefixedText();
2409                         $dbName = $this->getPrefixedDBkey();
2410
2411                         // Check for explicit whitelisting with and without underscores
2412                         if ( in_array( $name, $wgWhitelistRead, true ) || in_array( $dbName, $wgWhitelistRead, true ) ) {
2413                                 $whitelisted = true;
2414                         } elseif ( $this->getNamespace() == NS_MAIN ) {
2415                                 # Old settings might have the title prefixed with
2416                                 # a colon for main-namespace pages
2417                                 if ( in_array( ':' . $name, $wgWhitelistRead ) ) {
2418                                         $whitelisted = true;
2419                                 }
2420                         } elseif ( $this->isSpecialPage() ) {
2421                                 # If it's a special page, ditch the subpage bit and check again
2422                                 $name = $this->getDBkey();
2423                                 list( $name, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $name );
2424                                 if ( $name ) {
2425                                         $pure = SpecialPage::getTitleFor( $name )->getPrefixedText();
2426                                         if ( in_array( $pure, $wgWhitelistRead, true ) ) {
2427                                                 $whitelisted = true;
2428                                         }
2429                                 }
2430                         }
2431                 }
2432
2433                 if ( !$whitelisted && is_array( $wgWhitelistReadRegexp ) && !empty( $wgWhitelistReadRegexp ) ) {
2434                         $name = $this->getPrefixedText();
2435                         // Check for regex whitelisting
2436                         foreach ( $wgWhitelistReadRegexp as $listItem ) {
2437                                 if ( preg_match( $listItem, $name ) ) {
2438                                         $whitelisted = true;
2439                                         break;
2440                                 }
2441                         }
2442                 }
2443
2444                 if ( !$whitelisted ) {
2445                         # If the title is not whitelisted, give extensions a chance to do so...
2446                         Hooks::run( 'TitleReadWhitelist', [ $this, $user, &$whitelisted ] );
2447                         if ( !$whitelisted ) {
2448                                 $errors[] = $this->missingPermissionError( $action, $short );
2449                         }
2450                 }
2451
2452                 return $errors;
2453         }
2454
2455         /**
2456          * Get a description array when the user doesn't have the right to perform
2457          * $action (i.e. when User::isAllowed() returns false)
2458          *
2459          * @param string $action The action to check
2460          * @param bool $short Short circuit on first error
2461          * @return array Array containing an error message key and any parameters
2462          */
2463         private function missingPermissionError( $action, $short ) {
2464                 // We avoid expensive display logic for quickUserCan's and such
2465                 if ( $short ) {
2466                         return [ 'badaccess-group0' ];
2467                 }
2468
2469                 return User::newFatalPermissionDeniedStatus( $action )->getErrorsArray()[0];
2470         }
2471
2472         /**
2473          * Can $user perform $action on this page? This is an internal function,
2474          * with multiple levels of checks depending on performance needs; see $rigor below.
2475          * It does not check wfReadOnly().
2476          *
2477          * @param string $action Action that permission needs to be checked for
2478          * @param User $user User to check
2479          * @param string $rigor One of (quick,full,secure)
2480          *   - quick  : does cheap permission checks from replica DBs (usable for GUI creation)
2481          *   - full   : does cheap and expensive checks possibly from a replica DB
2482          *   - secure : does cheap and expensive checks, using the master as needed
2483          * @param bool $short Set this to true to stop after the first permission error.
2484          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
2485          */
2486         protected function getUserPermissionsErrorsInternal(
2487                 $action, $user, $rigor = 'secure', $short = false
2488         ) {
2489                 if ( $rigor === true ) {
2490                         $rigor = 'secure'; // b/c
2491                 } elseif ( $rigor === false ) {
2492                         $rigor = 'quick'; // b/c
2493                 } elseif ( !in_array( $rigor, [ 'quick', 'full', 'secure' ] ) ) {
2494                         throw new Exception( "Invalid rigor parameter '$rigor'." );
2495                 }
2496
2497                 # Read has special handling
2498                 if ( $action == 'read' ) {
2499                         $checks = [
2500                                 'checkPermissionHooks',
2501                                 'checkReadPermissions',
2502                                 'checkUserBlock', // for wgBlockDisablesLogin
2503                         ];
2504                 # Don't call checkSpecialsAndNSPermissions or checkCSSandJSPermissions
2505                 # here as it will lead to duplicate error messages. This is okay to do
2506                 # since anywhere that checks for create will also check for edit, and
2507                 # those checks are called for edit.
2508                 } elseif ( $action == 'create' ) {
2509                         $checks = [
2510                                 'checkQuickPermissions',
2511                                 'checkPermissionHooks',
2512                                 'checkPageRestrictions',
2513                                 'checkCascadingSourcesRestrictions',
2514                                 'checkActionPermissions',
2515                                 'checkUserBlock'
2516                         ];
2517                 } else {
2518                         $checks = [
2519                                 'checkQuickPermissions',
2520                                 'checkPermissionHooks',
2521                                 'checkSpecialsAndNSPermissions',
2522                                 'checkCSSandJSPermissions',
2523                                 'checkPageRestrictions',
2524                                 'checkCascadingSourcesRestrictions',
2525                                 'checkActionPermissions',
2526                                 'checkUserBlock'
2527                         ];
2528                 }
2529
2530                 $errors = [];
2531                 while ( count( $checks ) > 0 &&
2532                                 !( $short && count( $errors ) > 0 ) ) {
2533                         $method = array_shift( $checks );
2534                         $errors = $this->$method( $action, $user, $errors, $rigor, $short );
2535                 }
2536
2537                 return $errors;
2538         }
2539
2540         /**
2541          * Get a filtered list of all restriction types supported by this wiki.
2542          * @param bool $exists True to get all restriction types that apply to
2543          * titles that do exist, False for all restriction types that apply to
2544          * titles that do not exist
2545          * @return array
2546          */
2547         public static function getFilteredRestrictionTypes( $exists = true ) {
2548                 global $wgRestrictionTypes;
2549                 $types = $wgRestrictionTypes;
2550                 if ( $exists ) {
2551                         # Remove the create restriction for existing titles
2552                         $types = array_diff( $types, [ 'create' ] );
2553                 } else {
2554                         # Only the create and upload restrictions apply to non-existing titles
2555                         $types = array_intersect( $types, [ 'create', 'upload' ] );
2556                 }
2557                 return $types;
2558         }
2559
2560         /**
2561          * Returns restriction types for the current Title
2562          *
2563          * @return array Applicable restriction types
2564          */
2565         public function getRestrictionTypes() {
2566                 if ( $this->isSpecialPage() ) {
2567                         return [];
2568                 }
2569
2570                 $types = self::getFilteredRestrictionTypes( $this->exists() );
2571
2572                 if ( $this->getNamespace() != NS_FILE ) {
2573                         # Remove the upload restriction for non-file titles
2574                         $types = array_diff( $types, [ 'upload' ] );
2575                 }
2576
2577                 Hooks::run( 'TitleGetRestrictionTypes', [ $this, &$types ] );
2578
2579                 wfDebug( __METHOD__ . ': applicable restrictions to [[' .
2580                         $this->getPrefixedText() . ']] are {' . implode( ',', $types ) . "}\n" );
2581
2582                 return $types;
2583         }
2584
2585         /**
2586          * Is this title subject to title protection?
2587          * Title protection is the one applied against creation of such title.
2588          *
2589          * @return array|bool An associative array representing any existent title
2590          *   protection, or false if there's none.
2591          */
2592         public function getTitleProtection() {
2593                 $protection = $this->getTitleProtectionInternal();
2594                 if ( $protection ) {
2595                         if ( $protection['permission'] == 'sysop' ) {
2596                                 $protection['permission'] = 'editprotected'; // B/C
2597                         }
2598                         if ( $protection['permission'] == 'autoconfirmed' ) {
2599                                 $protection['permission'] = 'editsemiprotected'; // B/C
2600                         }
2601                 }
2602                 return $protection;
2603         }
2604
2605         /**
2606          * Fetch title protection settings
2607          *
2608          * To work correctly, $this->loadRestrictions() needs to have access to the
2609          * actual protections in the database without munging 'sysop' =>
2610          * 'editprotected' and 'autoconfirmed' => 'editsemiprotected'. Other
2611          * callers probably want $this->getTitleProtection() instead.
2612          *
2613          * @return array|bool
2614          */
2615         protected function getTitleProtectionInternal() {
2616                 // Can't protect pages in special namespaces
2617                 if ( $this->getNamespace() < 0 ) {
2618                         return false;
2619                 }
2620
2621                 // Can't protect pages that exist.
2622                 if ( $this->exists() ) {
2623                         return false;
2624                 }
2625
2626                 if ( $this->mTitleProtection === null ) {
2627                         $dbr = wfGetDB( DB_REPLICA );
2628                         $res = $dbr->select(
2629                                 'protected_titles',
2630                                 [
2631                                         'user' => 'pt_user',
2632                                         'reason' => 'pt_reason',
2633                                         'expiry' => 'pt_expiry',
2634                                         'permission' => 'pt_create_perm'
2635                                 ],
2636                                 [ 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ],
2637                                 __METHOD__
2638                         );
2639
2640                         // fetchRow returns false if there are no rows.
2641                         $row = $dbr->fetchRow( $res );
2642                         if ( $row ) {
2643                                 $row['expiry'] = $dbr->decodeExpiry( $row['expiry'] );
2644                         }
2645                         $this->mTitleProtection = $row;
2646                 }
2647                 return $this->mTitleProtection;
2648         }
2649
2650         /**
2651          * Remove any title protection due to page existing
2652          */
2653         public function deleteTitleProtection() {
2654                 $dbw = wfGetDB( DB_MASTER );
2655
2656                 $dbw->delete(
2657                         'protected_titles',
2658                         [ 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ],
2659                         __METHOD__
2660                 );
2661                 $this->mTitleProtection = false;
2662         }
2663
2664         /**
2665          * Is this page "semi-protected" - the *only* protection levels are listed
2666          * in $wgSemiprotectedRestrictionLevels?
2667          *
2668          * @param string $action Action to check (default: edit)
2669          * @return bool
2670          */
2671         public function isSemiProtected( $action = 'edit' ) {
2672                 global $wgSemiprotectedRestrictionLevels;
2673
2674                 $restrictions = $this->getRestrictions( $action );
2675                 $semi = $wgSemiprotectedRestrictionLevels;
2676                 if ( !$restrictions || !$semi ) {
2677                         // Not protected, or all protection is full protection
2678                         return false;
2679                 }
2680
2681                 // Remap autoconfirmed to editsemiprotected for BC
2682                 foreach ( array_keys( $semi, 'autoconfirmed' ) as $key ) {
2683                         $semi[$key] = 'editsemiprotected';
2684                 }
2685                 foreach ( array_keys( $restrictions, 'autoconfirmed' ) as $key ) {
2686                         $restrictions[$key] = 'editsemiprotected';
2687                 }
2688
2689                 return !array_diff( $restrictions, $semi );
2690         }
2691
2692         /**
2693          * Does the title correspond to a protected article?
2694          *
2695          * @param string $action The action the page is protected from,
2696          * by default checks all actions.
2697          * @return bool
2698          */
2699         public function isProtected( $action = '' ) {
2700                 global $wgRestrictionLevels;
2701
2702                 $restrictionTypes = $this->getRestrictionTypes();
2703
2704                 # Special pages have inherent protection
2705                 if ( $this->isSpecialPage() ) {
2706                         return true;
2707                 }
2708
2709                 # Check regular protection levels
2710                 foreach ( $restrictionTypes as $type ) {
2711                         if ( $action == $type || $action == '' ) {
2712                                 $r = $this->getRestrictions( $type );
2713                                 foreach ( $wgRestrictionLevels as $level ) {
2714                                         if ( in_array( $level, $r ) && $level != '' ) {
2715                                                 return true;
2716                                         }
2717                                 }
2718                         }
2719                 }
2720
2721                 return false;
2722         }
2723
2724         /**
2725          * Determines if $user is unable to edit this page because it has been protected
2726          * by $wgNamespaceProtection.
2727          *
2728          * @param User $user User object to check permissions
2729          * @return bool
2730          */
2731         public function isNamespaceProtected( User $user ) {
2732                 global $wgNamespaceProtection;
2733
2734                 if ( isset( $wgNamespaceProtection[$this->mNamespace] ) ) {
2735                         foreach ( (array)$wgNamespaceProtection[$this->mNamespace] as $right ) {
2736                                 if ( $right != '' && !$user->isAllowed( $right ) ) {
2737                                         return true;
2738                                 }
2739                         }
2740                 }
2741                 return false;
2742         }
2743
2744         /**
2745          * Cascading protection: Return true if cascading restrictions apply to this page, false if not.
2746          *
2747          * @return bool If the page is subject to cascading restrictions.
2748          */
2749         public function isCascadeProtected() {
2750                 list( $sources, /* $restrictions */ ) = $this->getCascadeProtectionSources( false );
2751                 return ( $sources > 0 );
2752         }
2753
2754         /**
2755          * Determines whether cascading protection sources have already been loaded from
2756          * the database.
2757          *
2758          * @param bool $getPages True to check if the pages are loaded, or false to check
2759          * if the status is loaded.
2760          * @return bool Whether or not the specified information has been loaded
2761          * @since 1.23
2762          */
2763         public function areCascadeProtectionSourcesLoaded( $getPages = true ) {
2764                 return $getPages ? $this->mCascadeSources !== null : $this->mHasCascadingRestrictions !== null;
2765         }
2766
2767         /**
2768          * Cascading protection: Get the source of any cascading restrictions on this page.
2769          *
2770          * @param bool $getPages Whether or not to retrieve the actual pages
2771          *        that the restrictions have come from and the actual restrictions
2772          *        themselves.
2773          * @return array Two elements: First is an array of Title objects of the
2774          *        pages from which cascading restrictions have come, false for
2775          *        none, or true if such restrictions exist but $getPages was not
2776          *        set. Second is an array like that returned by
2777          *        Title::getAllRestrictions(), or an empty array if $getPages is
2778          *        false.
2779          */
2780         public function getCascadeProtectionSources( $getPages = true ) {
2781                 $pagerestrictions = [];
2782
2783                 if ( $this->mCascadeSources !== null && $getPages ) {
2784                         return [ $this->mCascadeSources, $this->mCascadingRestrictions ];
2785                 } elseif ( $this->mHasCascadingRestrictions !== null && !$getPages ) {
2786                         return [ $this->mHasCascadingRestrictions, $pagerestrictions ];
2787                 }
2788
2789                 $dbr = wfGetDB( DB_REPLICA );
2790
2791                 if ( $this->getNamespace() == NS_FILE ) {
2792                         $tables = [ 'imagelinks', 'page_restrictions' ];
2793                         $where_clauses = [
2794                                 'il_to' => $this->getDBkey(),
2795                                 'il_from=pr_page',
2796                                 'pr_cascade' => 1
2797                         ];
2798                 } else {
2799                         $tables = [ 'templatelinks', 'page_restrictions' ];
2800                         $where_clauses = [
2801                                 'tl_namespace' => $this->getNamespace(),
2802                                 'tl_title' => $this->getDBkey(),
2803                                 'tl_from=pr_page',
2804                                 'pr_cascade' => 1
2805                         ];
2806                 }
2807
2808                 if ( $getPages ) {
2809                         $cols = [ 'pr_page', 'page_namespace', 'page_title',
2810                                 'pr_expiry', 'pr_type', 'pr_level' ];
2811                         $where_clauses[] = 'page_id=pr_page';
2812                         $tables[] = 'page';
2813                 } else {
2814                         $cols = [ 'pr_expiry' ];
2815                 }
2816
2817                 $res = $dbr->select( $tables, $cols, $where_clauses, __METHOD__ );
2818
2819                 $sources = $getPages ? [] : false;
2820                 $now = wfTimestampNow();
2821
2822                 foreach ( $res as $row ) {
2823                         $expiry = $dbr->decodeExpiry( $row->pr_expiry );
2824                         if ( $expiry > $now ) {
2825                                 if ( $getPages ) {
2826                                         $page_id = $row->pr_page;
2827                                         $page_ns = $row->page_namespace;
2828                                         $page_title = $row->page_title;
2829                                         $sources[$page_id] = Title::makeTitle( $page_ns, $page_title );
2830                                         # Add groups needed for each restriction type if its not already there
2831                                         # Make sure this restriction type still exists
2832
2833                                         if ( !isset( $pagerestrictions[$row->pr_type] ) ) {
2834                                                 $pagerestrictions[$row->pr_type] = [];
2835                                         }
2836
2837                                         if (
2838                                                 isset( $pagerestrictions[$row->pr_type] )
2839                                                 && !in_array( $row->pr_level, $pagerestrictions[$row->pr_type] )
2840                                         ) {
2841                                                 $pagerestrictions[$row->pr_type][] = $row->pr_level;
2842                                         }
2843                                 } else {
2844                                         $sources = true;
2845                                 }
2846                         }
2847                 }
2848
2849                 if ( $getPages ) {
2850                         $this->mCascadeSources = $sources;
2851                         $this->mCascadingRestrictions = $pagerestrictions;
2852                 } else {
2853                         $this->mHasCascadingRestrictions = $sources;
2854                 }
2855
2856                 return [ $sources, $pagerestrictions ];
2857         }
2858
2859         /**
2860          * Accessor for mRestrictionsLoaded
2861          *
2862          * @return bool Whether or not the page's restrictions have already been
2863          * loaded from the database
2864          * @since 1.23
2865          */
2866         public function areRestrictionsLoaded() {
2867                 return $this->mRestrictionsLoaded;
2868         }
2869
2870         /**
2871          * Accessor/initialisation for mRestrictions
2872          *
2873          * @param string $action Action that permission needs to be checked for
2874          * @return array Restriction levels needed to take the action. All levels are
2875          *     required. Note that restriction levels are normally user rights, but 'sysop'
2876          *     and 'autoconfirmed' are also allowed for backwards compatibility. These should
2877          *     be mapped to 'editprotected' and 'editsemiprotected' respectively.
2878          */
2879         public function getRestrictions( $action ) {
2880                 if ( !$this->mRestrictionsLoaded ) {
2881                         $this->loadRestrictions();
2882                 }
2883                 return isset( $this->mRestrictions[$action] )
2884                                 ? $this->mRestrictions[$action]
2885                                 : [];
2886         }
2887
2888         /**
2889          * Accessor/initialisation for mRestrictions
2890          *
2891          * @return array Keys are actions, values are arrays as returned by
2892          *     Title::getRestrictions()
2893          * @since 1.23
2894          */
2895         public function getAllRestrictions() {
2896                 if ( !$this->mRestrictionsLoaded ) {
2897                         $this->loadRestrictions();
2898                 }
2899                 return $this->mRestrictions;
2900         }
2901
2902         /**
2903          * Get the expiry time for the restriction against a given action
2904          *
2905          * @param string $action
2906          * @return string|bool 14-char timestamp, or 'infinity' if the page is protected forever
2907          *     or not protected at all, or false if the action is not recognised.
2908          */
2909         public function getRestrictionExpiry( $action ) {
2910                 if ( !$this->mRestrictionsLoaded ) {
2911                         $this->loadRestrictions();
2912                 }
2913                 return isset( $this->mRestrictionsExpiry[$action] ) ? $this->mRestrictionsExpiry[$action] : false;
2914         }
2915
2916         /**
2917          * Returns cascading restrictions for the current article
2918          *
2919          * @return bool
2920          */
2921         function areRestrictionsCascading() {
2922                 if ( !$this->mRestrictionsLoaded ) {
2923                         $this->loadRestrictions();
2924                 }
2925
2926                 return $this->mCascadeRestriction;
2927         }
2928
2929         /**
2930          * Compiles list of active page restrictions from both page table (pre 1.10)
2931          * and page_restrictions table for this existing page.
2932          * Public for usage by LiquidThreads.
2933          *
2934          * @param array $rows Array of db result objects
2935          * @param string $oldFashionedRestrictions Comma-separated list of page
2936          *   restrictions from page table (pre 1.10)
2937          */
2938         public function loadRestrictionsFromRows( $rows, $oldFashionedRestrictions = null ) {
2939                 $dbr = wfGetDB( DB_REPLICA );
2940
2941                 $restrictionTypes = $this->getRestrictionTypes();
2942
2943                 foreach ( $restrictionTypes as $type ) {
2944                         $this->mRestrictions[$type] = [];
2945                         $this->mRestrictionsExpiry[$type] = 'infinity';
2946                 }
2947
2948                 $this->mCascadeRestriction = false;
2949
2950                 # Backwards-compatibility: also load the restrictions from the page record (old format).
2951                 if ( $oldFashionedRestrictions !== null ) {
2952                         $this->mOldRestrictions = $oldFashionedRestrictions;
2953                 }
2954
2955                 if ( $this->mOldRestrictions === false ) {
2956                         $this->mOldRestrictions = $dbr->selectField( 'page', 'page_restrictions',
2957                                 [ 'page_id' => $this->getArticleID() ], __METHOD__ );
2958                 }
2959
2960                 if ( $this->mOldRestrictions != '' ) {
2961                         foreach ( explode( ':', trim( $this->mOldRestrictions ) ) as $restrict ) {
2962                                 $temp = explode( '=', trim( $restrict ) );
2963                                 if ( count( $temp ) == 1 ) {
2964                                         // old old format should be treated as edit/move restriction
2965                                         $this->mRestrictions['edit'] = explode( ',', trim( $temp[0] ) );
2966                                         $this->mRestrictions['move'] = explode( ',', trim( $temp[0] ) );
2967                                 } else {
2968                                         $restriction = trim( $temp[1] );
2969                                         if ( $restriction != '' ) { // some old entries are empty
2970                                                 $this->mRestrictions[$temp[0]] = explode( ',', $restriction );
2971                                         }
2972                                 }
2973                         }
2974                 }
2975
2976                 if ( count( $rows ) ) {
2977                         # Current system - load second to make them override.
2978                         $now = wfTimestampNow();
2979
2980                         # Cycle through all the restrictions.
2981                         foreach ( $rows as $row ) {
2982                                 // Don't take care of restrictions types that aren't allowed
2983                                 if ( !in_array( $row->pr_type, $restrictionTypes ) ) {
2984                                         continue;
2985                                 }
2986
2987                                 $expiry = $dbr->decodeExpiry( $row->pr_expiry );
2988
2989                                 // Only apply the restrictions if they haven't expired!
2990                                 if ( !$expiry || $expiry > $now ) {
2991                                         $this->mRestrictionsExpiry[$row->pr_type] = $expiry;
2992                                         $this->mRestrictions[$row->pr_type] = explode( ',', trim( $row->pr_level ) );
2993
2994                                         $this->mCascadeRestriction |= $row->pr_cascade;
2995                                 }
2996                         }
2997                 }
2998
2999                 $this->mRestrictionsLoaded = true;
3000         }
3001
3002         /**
3003          * Load restrictions from the page_restrictions table
3004          *
3005          * @param string $oldFashionedRestrictions Comma-separated list of page
3006          *   restrictions from page table (pre 1.10)
3007          */
3008         public function loadRestrictions( $oldFashionedRestrictions = null ) {
3009                 if ( $this->mRestrictionsLoaded ) {
3010                         return;
3011                 }
3012
3013                 $id = $this->getArticleID();
3014                 if ( $id ) {
3015                         $cache = ObjectCache::getMainWANInstance();
3016                         $rows = $cache->getWithSetCallback(
3017                                 // Page protections always leave a new null revision
3018                                 $cache->makeKey( 'page-restrictions', $id, $this->getLatestRevID() ),
3019                                 $cache::TTL_DAY,
3020                                 function ( $curValue, &$ttl, array &$setOpts ) {
3021                                         $dbr = wfGetDB( DB_REPLICA );
3022
3023                                         $setOpts += Database::getCacheSetOptions( $dbr );
3024
3025                                         return iterator_to_array(
3026                                                 $dbr->select(
3027                                                         'page_restrictions',
3028                                                         [ 'pr_type', 'pr_expiry', 'pr_level', 'pr_cascade' ],
3029                                                         [ 'pr_page' => $this->getArticleID() ],
3030                                                         __METHOD__
3031                                                 )
3032                                         );
3033                                 }
3034                         );
3035
3036                         $this->loadRestrictionsFromRows( $rows, $oldFashionedRestrictions );
3037                 } else {
3038                         $title_protection = $this->getTitleProtectionInternal();
3039
3040                         if ( $title_protection ) {
3041                                 $now = wfTimestampNow();
3042                                 $expiry = wfGetDB( DB_REPLICA )->decodeExpiry( $title_protection['expiry'] );
3043
3044                                 if ( !$expiry || $expiry > $now ) {
3045                                         // Apply the restrictions
3046                                         $this->mRestrictionsExpiry['create'] = $expiry;
3047                                         $this->mRestrictions['create'] =
3048                                                 explode( ',', trim( $title_protection['permission'] ) );
3049                                 } else { // Get rid of the old restrictions
3050                                         $this->mTitleProtection = false;
3051                                 }
3052                         } else {
3053                                 $this->mRestrictionsExpiry['create'] = 'infinity';
3054                         }
3055                         $this->mRestrictionsLoaded = true;
3056                 }
3057         }
3058
3059         /**
3060          * Flush the protection cache in this object and force reload from the database.
3061          * This is used when updating protection from WikiPage::doUpdateRestrictions().
3062          */
3063         public function flushRestrictions() {
3064                 $this->mRestrictionsLoaded = false;
3065                 $this->mTitleProtection = null;
3066         }
3067
3068         /**
3069          * Purge expired restrictions from the page_restrictions table
3070          *
3071          * This will purge no more than $wgUpdateRowsPerQuery page_restrictions rows
3072          */
3073         static function purgeExpiredRestrictions() {
3074                 if ( wfReadOnly() ) {
3075                         return;
3076                 }
3077
3078                 DeferredUpdates::addUpdate( new AtomicSectionUpdate(
3079                         wfGetDB( DB_MASTER ),
3080                         __METHOD__,
3081                         function ( IDatabase $dbw, $fname ) {
3082                                 $config = MediaWikiServices::getInstance()->getMainConfig();
3083                                 $ids = $dbw->selectFieldValues(
3084                                         'page_restrictions',
3085                                         'pr_id',
3086                                         [ 'pr_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ],
3087                                         $fname,
3088                                         [ 'LIMIT' => $config->get( 'UpdateRowsPerQuery' ) ] // T135470
3089                                 );
3090                                 if ( $ids ) {
3091                                         $dbw->delete( 'page_restrictions', [ 'pr_id' => $ids ], $fname );
3092                                 }
3093                         }
3094                 ) );
3095
3096                 DeferredUpdates::addUpdate( new AtomicSectionUpdate(
3097                         wfGetDB( DB_MASTER ),
3098                         __METHOD__,
3099                         function ( IDatabase $dbw, $fname ) {
3100                                 $dbw->delete(
3101                                         'protected_titles',
3102                                         [ 'pt_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ],
3103                                         $fname
3104                                 );
3105                         }
3106                 ) );
3107         }
3108
3109         /**
3110          * Does this have subpages?  (Warning, usually requires an extra DB query.)
3111          *
3112          * @return bool
3113          */
3114         public function hasSubpages() {
3115                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
3116                         # Duh
3117                         return false;
3118                 }
3119
3120                 # We dynamically add a member variable for the purpose of this method
3121                 # alone to cache the result.  There's no point in having it hanging
3122                 # around uninitialized in every Title object; therefore we only add it
3123                 # if needed and don't declare it statically.
3124                 if ( $this->mHasSubpages === null ) {
3125                         $this->mHasSubpages = false;
3126                         $subpages = $this->getSubpages( 1 );
3127                         if ( $subpages instanceof TitleArray ) {
3128                                 $this->mHasSubpages = (bool)$subpages->count();
3129                         }
3130                 }
3131
3132                 return $this->mHasSubpages;
3133         }
3134
3135         /**
3136          * Get all subpages of this page.
3137          *
3138          * @param int $limit Maximum number of subpages to fetch; -1 for no limit
3139          * @return TitleArray|array TitleArray, or empty array if this page's namespace
3140          *  doesn't allow subpages
3141          */
3142         public function getSubpages( $limit = -1 ) {
3143                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3144                         return [];
3145                 }
3146
3147                 $dbr = wfGetDB( DB_REPLICA );
3148                 $conds['page_namespace'] = $this->getNamespace();
3149                 $conds[] = 'page_title ' . $dbr->buildLike( $this->getDBkey() . '/', $dbr->anyString() );
3150                 $options = [];
3151                 if ( $limit > -1 ) {
3152                         $options['LIMIT'] = $limit;
3153                 }
3154                 $this->mSubpages = TitleArray::newFromResult(
3155                         $dbr->select( 'page',
3156                                 [ 'page_id', 'page_namespace', 'page_title', 'page_is_redirect' ],
3157                                 $conds,
3158                                 __METHOD__,
3159                                 $options
3160                         )
3161                 );
3162                 return $this->mSubpages;
3163         }
3164
3165         /**
3166          * Is there a version of this page in the deletion archive?
3167          *
3168          * @return int The number of archived revisions
3169          */
3170         public function isDeleted() {
3171                 if ( $this->getNamespace() < 0 ) {
3172                         $n = 0;
3173                 } else {
3174                         $dbr = wfGetDB( DB_REPLICA );
3175
3176                         $n = $dbr->selectField( 'archive', 'COUNT(*)',
3177                                 [ 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ],
3178                                 __METHOD__
3179                         );
3180                         if ( $this->getNamespace() == NS_FILE ) {
3181                                 $n += $dbr->selectField( 'filearchive', 'COUNT(*)',
3182                                         [ 'fa_name' => $this->getDBkey() ],
3183                                         __METHOD__
3184                                 );
3185                         }
3186                 }
3187                 return (int)$n;
3188         }
3189
3190         /**
3191          * Is there a version of this page in the deletion archive?
3192          *
3193          * @return bool
3194          */
3195         public function isDeletedQuick() {
3196                 if ( $this->getNamespace() < 0 ) {
3197                         return false;
3198                 }
3199                 $dbr = wfGetDB( DB_REPLICA );
3200                 $deleted = (bool)$dbr->selectField( 'archive', '1',
3201                         [ 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ],
3202                         __METHOD__
3203                 );
3204                 if ( !$deleted && $this->getNamespace() == NS_FILE ) {
3205                         $deleted = (bool)$dbr->selectField( 'filearchive', '1',
3206                                 [ 'fa_name' => $this->getDBkey() ],
3207                                 __METHOD__
3208                         );
3209                 }
3210                 return $deleted;
3211         }
3212
3213         /**
3214          * Get the article ID for this Title from the link cache,
3215          * adding it if necessary
3216          *
3217          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select
3218          *  for update
3219          * @return int The ID
3220          */
3221         public function getArticleID( $flags = 0 ) {
3222                 if ( $this->getNamespace() < 0 ) {
3223                         $this->mArticleID = 0;
3224                         return $this->mArticleID;
3225                 }
3226                 $linkCache = LinkCache::singleton();
3227                 if ( $flags & self::GAID_FOR_UPDATE ) {
3228                         $oldUpdate = $linkCache->forUpdate( true );
3229                         $linkCache->clearLink( $this );
3230                         $this->mArticleID = $linkCache->addLinkObj( $this );
3231                         $linkCache->forUpdate( $oldUpdate );
3232                 } else {
3233                         if ( -1 == $this->mArticleID ) {
3234                                 $this->mArticleID = $linkCache->addLinkObj( $this );
3235                         }
3236                 }
3237                 return $this->mArticleID;
3238         }
3239
3240         /**
3241          * Is this an article that is a redirect page?
3242          * Uses link cache, adding it if necessary
3243          *
3244          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3245          * @return bool
3246          */
3247         public function isRedirect( $flags = 0 ) {
3248                 if ( !is_null( $this->mRedirect ) ) {
3249                         return $this->mRedirect;
3250                 }
3251                 if ( !$this->getArticleID( $flags ) ) {
3252                         $this->mRedirect = false;
3253                         return $this->mRedirect;
3254                 }
3255
3256                 $linkCache = LinkCache::singleton();
3257                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3258                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'redirect' );
3259                 if ( $cached === null ) {
3260                         # Trust LinkCache's state over our own
3261                         # LinkCache is telling us that the page doesn't exist, despite there being cached
3262                         # data relating to an existing page in $this->mArticleID. Updaters should clear
3263                         # LinkCache as appropriate, or use $flags = Title::GAID_FOR_UPDATE. If that flag is
3264                         # set, then LinkCache will definitely be up to date here, since getArticleID() forces
3265                         # LinkCache to refresh its data from the master.
3266                         $this->mRedirect = false;
3267                         return $this->mRedirect;
3268                 }
3269
3270                 $this->mRedirect = (bool)$cached;
3271
3272                 return $this->mRedirect;
3273         }
3274
3275         /**
3276          * What is the length of this page?
3277          * Uses link cache, adding it if necessary
3278          *
3279          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3280          * @return int
3281          */
3282         public function getLength( $flags = 0 ) {
3283                 if ( $this->mLength != -1 ) {
3284                         return $this->mLength;
3285                 }
3286                 if ( !$this->getArticleID( $flags ) ) {
3287                         $this->mLength = 0;
3288                         return $this->mLength;
3289                 }
3290                 $linkCache = LinkCache::singleton();
3291                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3292                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'length' );
3293                 if ( $cached === null ) {
3294                         # Trust LinkCache's state over our own, as for isRedirect()
3295                         $this->mLength = 0;
3296                         return $this->mLength;
3297                 }
3298
3299                 $this->mLength = intval( $cached );
3300
3301                 return $this->mLength;
3302         }
3303
3304         /**
3305          * What is the page_latest field for this page?
3306          *
3307          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3308          * @return int Int or 0 if the page doesn't exist
3309          */
3310         public function getLatestRevID( $flags = 0 ) {
3311                 if ( !( $flags & Title::GAID_FOR_UPDATE ) && $this->mLatestID !== false ) {
3312                         return intval( $this->mLatestID );
3313                 }
3314                 if ( !$this->getArticleID( $flags ) ) {
3315                         $this->mLatestID = 0;
3316                         return $this->mLatestID;
3317                 }
3318                 $linkCache = LinkCache::singleton();
3319                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3320                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'revision' );
3321                 if ( $cached === null ) {
3322                         # Trust LinkCache's state over our own, as for isRedirect()
3323                         $this->mLatestID = 0;
3324                         return $this->mLatestID;
3325                 }
3326
3327                 $this->mLatestID = intval( $cached );
3328
3329                 return $this->mLatestID;
3330         }
3331
3332         /**
3333          * This clears some fields in this object, and clears any associated
3334          * keys in the "bad links" section of the link cache.
3335          *
3336          * - This is called from WikiPage::doEditContent() and WikiPage::insertOn() to allow
3337          * loading of the new page_id. It's also called from
3338          * WikiPage::doDeleteArticleReal()
3339          *
3340          * @param int $newid The new Article ID
3341          */
3342         public function resetArticleID( $newid ) {
3343                 $linkCache = LinkCache::singleton();
3344                 $linkCache->clearLink( $this );
3345
3346                 if ( $newid === false ) {
3347                         $this->mArticleID = -1;
3348                 } else {
3349                         $this->mArticleID = intval( $newid );
3350                 }
3351                 $this->mRestrictionsLoaded = false;
3352                 $this->mRestrictions = [];
3353                 $this->mOldRestrictions = false;
3354                 $this->mRedirect = null;
3355                 $this->mLength = -1;
3356                 $this->mLatestID = false;
3357                 $this->mContentModel = false;
3358                 $this->mEstimateRevisions = null;
3359                 $this->mPageLanguage = false;
3360                 $this->mDbPageLanguage = false;
3361                 $this->mIsBigDeletion = null;
3362         }
3363
3364         public static function clearCaches() {
3365                 $linkCache = LinkCache::singleton();
3366                 $linkCache->clear();
3367
3368                 $titleCache = self::getTitleCache();
3369                 $titleCache->clear();
3370         }
3371
3372         /**
3373          * Capitalize a text string for a title if it belongs to a namespace that capitalizes
3374          *
3375          * @param string $text Containing title to capitalize
3376          * @param int $ns Namespace index, defaults to NS_MAIN
3377          * @return string Containing capitalized title
3378          */
3379         public static function capitalize( $text, $ns = NS_MAIN ) {
3380                 global $wgContLang;
3381
3382                 if ( MWNamespace::isCapitalized( $ns ) ) {
3383                         return $wgContLang->ucfirst( $text );
3384                 } else {
3385                         return $text;
3386                 }
3387         }
3388
3389         /**
3390          * Secure and split - main initialisation function for this object
3391          *
3392          * Assumes that mDbkeyform has been set, and is urldecoded
3393          * and uses underscores, but not otherwise munged.  This function
3394          * removes illegal characters, splits off the interwiki and
3395          * namespace prefixes, sets the other forms, and canonicalizes
3396          * everything.
3397          *
3398          * @throws MalformedTitleException On invalid titles
3399          * @return bool True on success
3400          */
3401         private function secureAndSplit() {
3402                 # Initialisation
3403                 $this->mInterwiki = '';
3404                 $this->mFragment = '';
3405                 $this->mNamespace = $this->mDefaultNamespace; # Usually NS_MAIN
3406
3407                 $dbkey = $this->mDbkeyform;
3408
3409                 // @note: splitTitleString() is a temporary hack to allow MediaWikiTitleCodec to share
3410                 //        the parsing code with Title, while avoiding massive refactoring.
3411                 // @todo: get rid of secureAndSplit, refactor parsing code.
3412                 // @note: getTitleParser() returns a TitleParser implementation which does not have a
3413                 //        splitTitleString method, but the only implementation (MediaWikiTitleCodec) does
3414                 $titleCodec = MediaWikiServices::getInstance()->getTitleParser();
3415                 // MalformedTitleException can be thrown here
3416                 $parts = $titleCodec->splitTitleString( $dbkey, $this->getDefaultNamespace() );
3417
3418                 # Fill fields
3419                 $this->setFragment( '#' . $parts['fragment'] );
3420                 $this->mInterwiki = $parts['interwiki'];
3421                 $this->mLocalInterwiki = $parts['local_interwiki'];
3422                 $this->mNamespace = $parts['namespace'];
3423                 $this->mUserCaseDBKey = $parts['user_case_dbkey'];
3424
3425                 $this->mDbkeyform = $parts['dbkey'];
3426                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
3427                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
3428
3429                 # We already know that some pages won't be in the database!
3430                 if ( $this->isExternal() || $this->mNamespace == NS_SPECIAL ) {
3431                         $this->mArticleID = 0;
3432                 }
3433
3434                 return true;
3435         }
3436
3437         /**
3438          * Get an array of Title objects linking to this Title
3439          * Also stores the IDs in the link cache.
3440          *
3441          * WARNING: do not use this function on arbitrary user-supplied titles!
3442          * On heavily-used templates it will max out the memory.
3443          *
3444          * @param array $options May be FOR UPDATE
3445          * @param string $table Table name
3446          * @param string $prefix Fields prefix
3447          * @return Title[] Array of Title objects linking here
3448          */
3449         public function getLinksTo( $options = [], $table = 'pagelinks', $prefix = 'pl' ) {
3450                 if ( count( $options ) > 0 ) {
3451                         $db = wfGetDB( DB_MASTER );
3452                 } else {
3453                         $db = wfGetDB( DB_REPLICA );
3454                 }
3455
3456                 $res = $db->select(
3457                         [ 'page', $table ],
3458                         self::getSelectFields(),
3459                         [
3460                                 "{$prefix}_from=page_id",
3461                                 "{$prefix}_namespace" => $this->getNamespace(),
3462                                 "{$prefix}_title" => $this->getDBkey() ],
3463                         __METHOD__,
3464                         $options
3465                 );
3466
3467                 $retVal = [];
3468                 if ( $res->numRows() ) {
3469                         $linkCache = LinkCache::singleton();
3470                         foreach ( $res as $row ) {
3471                                 $titleObj = Title::makeTitle( $row->page_namespace, $row->page_title );
3472                                 if ( $titleObj ) {
3473                                         $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3474                                         $retVal[] = $titleObj;
3475                                 }
3476                         }
3477                 }
3478                 return $retVal;
3479         }
3480
3481         /**
3482          * Get an array of Title objects using this Title as a template
3483          * Also stores the IDs in the link cache.
3484          *
3485          * WARNING: do not use this function on arbitrary user-supplied titles!
3486          * On heavily-used templates it will max out the memory.
3487          *
3488          * @param array $options Query option to Database::select()
3489          * @return Title[] Array of Title the Title objects linking here
3490          */
3491         public function getTemplateLinksTo( $options = [] ) {
3492                 return $this->getLinksTo( $options, 'templatelinks', 'tl' );
3493         }
3494
3495         /**
3496          * Get an array of Title objects linked from this Title
3497          * Also stores the IDs in the link cache.
3498          *
3499          * WARNING: do not use this function on arbitrary user-supplied titles!
3500          * On heavily-used templates it will max out the memory.
3501          *
3502          * @param array $options Query option to Database::select()
3503          * @param string $table Table name
3504          * @param string $prefix Fields prefix
3505          * @return array Array of Title objects linking here
3506          */
3507         public function getLinksFrom( $options = [], $table = 'pagelinks', $prefix = 'pl' ) {
3508                 $id = $this->getArticleID();
3509
3510                 # If the page doesn't exist; there can't be any link from this page
3511                 if ( !$id ) {
3512                         return [];
3513                 }
3514
3515                 $db = wfGetDB( DB_REPLICA );
3516
3517                 $blNamespace = "{$prefix}_namespace";
3518                 $blTitle = "{$prefix}_title";
3519
3520                 $res = $db->select(
3521                         [ $table, 'page' ],
3522                         array_merge(
3523                                 [ $blNamespace, $blTitle ],
3524                                 WikiPage::selectFields()
3525                         ),
3526                         [ "{$prefix}_from" => $id ],
3527                         __METHOD__,
3528                         $options,
3529                         [ 'page' => [
3530                                 'LEFT JOIN',
3531                                 [ "page_namespace=$blNamespace", "page_title=$blTitle" ]
3532                         ] ]
3533                 );
3534
3535                 $retVal = [];
3536                 $linkCache = LinkCache::singleton();
3537                 foreach ( $res as $row ) {
3538                         if ( $row->page_id ) {
3539                                 $titleObj = Title::newFromRow( $row );
3540                         } else {
3541                                 $titleObj = Title::makeTitle( $row->$blNamespace, $row->$blTitle );
3542                                 $linkCache->addBadLinkObj( $titleObj );
3543                         }
3544                         $retVal[] = $titleObj;
3545                 }
3546
3547                 return $retVal;
3548         }
3549
3550         /**
3551          * Get an array of Title objects used on this Title as a template
3552          * Also stores the IDs in the link cache.
3553          *
3554          * WARNING: do not use this function on arbitrary user-supplied titles!
3555          * On heavily-used templates it will max out the memory.
3556          *
3557          * @param array $options May be FOR UPDATE
3558          * @return Title[] Array of Title the Title objects used here
3559          */
3560         public function getTemplateLinksFrom( $options = [] ) {
3561                 return $this->getLinksFrom( $options, 'templatelinks', 'tl' );
3562         }
3563
3564         /**
3565          * Get an array of Title objects referring to non-existent articles linked
3566          * from this page.
3567          *
3568          * @todo check if needed (used only in SpecialBrokenRedirects.php, and
3569          *   should use redirect table in this case).
3570          * @return Title[] Array of Title the Title objects
3571          */
3572         public function getBrokenLinksFrom() {
3573                 if ( $this->getArticleID() == 0 ) {
3574                         # All links from article ID 0 are false positives
3575                         return [];
3576                 }
3577
3578                 $dbr = wfGetDB( DB_REPLICA );
3579                 $res = $dbr->select(
3580                         [ 'page', 'pagelinks' ],
3581                         [ 'pl_namespace', 'pl_title' ],
3582                         [
3583                                 'pl_from' => $this->getArticleID(),
3584                                 'page_namespace IS NULL'
3585                         ],
3586                         __METHOD__, [],
3587                         [
3588                                 'page' => [
3589                                         'LEFT JOIN',
3590                                         [ 'pl_namespace=page_namespace', 'pl_title=page_title' ]
3591                                 ]
3592                         ]
3593                 );
3594
3595                 $retVal = [];
3596                 foreach ( $res as $row ) {
3597                         $retVal[] = Title::makeTitle( $row->pl_namespace, $row->pl_title );
3598                 }
3599                 return $retVal;
3600         }
3601
3602         /**
3603          * Get a list of URLs to purge from the CDN cache when this
3604          * page changes
3605          *
3606          * @return string[] Array of String the URLs
3607          */
3608         public function getCdnUrls() {
3609                 $urls = [
3610                         $this->getInternalURL(),
3611                         $this->getInternalURL( 'action=history' )
3612                 ];
3613
3614                 $pageLang = $this->getPageLanguage();
3615                 if ( $pageLang->hasVariants() ) {
3616                         $variants = $pageLang->getVariants();
3617                         foreach ( $variants as $vCode ) {
3618                                 $urls[] = $this->getInternalURL( $vCode );
3619                         }
3620                 }
3621
3622                 // If we are looking at a css/js user subpage, purge the action=raw.
3623                 if ( $this->isJsSubpage() ) {
3624                         $urls[] = $this->getInternalURL( 'action=raw&ctype=text/javascript' );
3625                 } elseif ( $this->isCssSubpage() ) {
3626                         $urls[] = $this->getInternalURL( 'action=raw&ctype=text/css' );
3627                 }
3628
3629                 Hooks::run( 'TitleSquidURLs', [ $this, &$urls ] );
3630                 return $urls;
3631         }
3632
3633         /**
3634          * @deprecated since 1.27 use getCdnUrls()
3635          */
3636         public function getSquidURLs() {
3637                 return $this->getCdnUrls();
3638         }
3639
3640         /**
3641          * Purge all applicable CDN URLs
3642          */
3643         public function purgeSquid() {
3644                 DeferredUpdates::addUpdate(
3645                         new CdnCacheUpdate( $this->getCdnUrls() ),
3646                         DeferredUpdates::PRESEND
3647                 );
3648         }
3649
3650         /**
3651          * Check whether a given move operation would be valid.
3652          * Returns true if ok, or a getUserPermissionsErrors()-like array otherwise
3653          *
3654          * @deprecated since 1.25, use MovePage's methods instead
3655          * @param Title $nt The new title
3656          * @param bool $auth Whether to check user permissions (uses $wgUser)
3657          * @param string $reason Is the log summary of the move, used for spam checking
3658          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3659          */
3660         public function isValidMoveOperation( &$nt, $auth = true, $reason = '' ) {
3661                 global $wgUser;
3662
3663                 if ( !( $nt instanceof Title ) ) {
3664                         // Normally we'd add this to $errors, but we'll get
3665                         // lots of syntax errors if $nt is not an object
3666                         return [ [ 'badtitletext' ] ];
3667                 }
3668
3669                 $mp = new MovePage( $this, $nt );
3670                 $errors = $mp->isValidMove()->getErrorsArray();
3671                 if ( $auth ) {
3672                         $errors = wfMergeErrorArrays(
3673                                 $errors,
3674                                 $mp->checkPermissions( $wgUser, $reason )->getErrorsArray()
3675                         );
3676                 }
3677
3678                 return $errors ?: true;
3679         }
3680
3681         /**
3682          * Check if the requested move target is a valid file move target
3683          * @todo move this to MovePage
3684          * @param Title $nt Target title
3685          * @return array List of errors
3686          */
3687         protected function validateFileMoveOperation( $nt ) {
3688                 global $wgUser;
3689
3690                 $errors = [];
3691
3692                 $destFile = wfLocalFile( $nt );
3693                 $destFile->load( File::READ_LATEST );
3694                 if ( !$wgUser->isAllowed( 'reupload-shared' )
3695                         && !$destFile->exists() && wfFindFile( $nt )
3696                 ) {
3697                         $errors[] = [ 'file-exists-sharedrepo' ];
3698                 }
3699
3700                 return $errors;
3701         }
3702
3703         /**
3704          * Move a title to a new location
3705          *
3706          * @deprecated since 1.25, use the MovePage class instead
3707          * @param Title $nt The new title
3708          * @param bool $auth Indicates whether $wgUser's permissions
3709          *  should be checked
3710          * @param string $reason The reason for the move
3711          * @param bool $createRedirect Whether to create a redirect from the old title to the new title.
3712          *  Ignored if the user doesn't have the suppressredirect right.
3713          * @param array $changeTags Applied to the entry in the move log and redirect page revision
3714          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3715          */
3716         public function moveTo( &$nt, $auth = true, $reason = '', $createRedirect = true,
3717                 array $changeTags = [] ) {
3718
3719                 global $wgUser;
3720                 $err = $this->isValidMoveOperation( $nt, $auth, $reason );
3721                 if ( is_array( $err ) ) {
3722                         // Auto-block user's IP if the account was "hard" blocked
3723                         $wgUser->spreadAnyEditBlock();
3724                         return $err;
3725                 }
3726                 // Check suppressredirect permission
3727                 if ( $auth && !$wgUser->isAllowed( 'suppressredirect' ) ) {
3728                         $createRedirect = true;
3729                 }
3730
3731                 $mp = new MovePage( $this, $nt );
3732                 $status = $mp->move( $wgUser, $reason, $createRedirect, $changeTags );
3733                 if ( $status->isOK() ) {
3734                         return true;
3735                 } else {
3736                         return $status->getErrorsArray();
3737                 }
3738         }
3739
3740         /**
3741          * Move this page's subpages to be subpages of $nt
3742          *
3743          * @param Title $nt Move target
3744          * @param bool $auth Whether $wgUser's permissions should be checked
3745          * @param string $reason The reason for the move
3746          * @param bool $createRedirect Whether to create redirects from the old subpages to
3747          *     the new ones Ignored if the user doesn't have the 'suppressredirect' right
3748          * @param array $changeTags Applied to the entry in the move log and redirect page revision
3749          * @return array Array with old page titles as keys, and strings (new page titles) or
3750          *     getUserPermissionsErrors()-like arrays (errors) as values, or a
3751          *     getUserPermissionsErrors()-like error array with numeric indices if
3752          *     no pages were moved
3753          */
3754         public function moveSubpages( $nt, $auth = true, $reason = '', $createRedirect = true,
3755                 array $changeTags = [] ) {
3756
3757                 global $wgMaximumMovedPages;
3758                 // Check permissions
3759                 if ( !$this->userCan( 'move-subpages' ) ) {
3760                         return [
3761                                 [ 'cant-move-subpages' ],
3762                         ];
3763                 }
3764                 // Do the source and target namespaces support subpages?
3765                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3766                         return [
3767                                 [ 'namespace-nosubpages', MWNamespace::getCanonicalName( $this->getNamespace() ) ],
3768                         ];
3769                 }
3770                 if ( !MWNamespace::hasSubpages( $nt->getNamespace() ) ) {
3771                         return [
3772                                 [ 'namespace-nosubpages', MWNamespace::getCanonicalName( $nt->getNamespace() ) ],
3773                         ];
3774                 }
3775
3776                 $subpages = $this->getSubpages( $wgMaximumMovedPages + 1 );
3777                 $retval = [];
3778                 $count = 0;
3779                 foreach ( $subpages as $oldSubpage ) {
3780                         $count++;
3781                         if ( $count > $wgMaximumMovedPages ) {
3782                                 $retval[$oldSubpage->getPrefixedText()] = [
3783                                         [ 'movepage-max-pages', $wgMaximumMovedPages ],
3784                                 ];
3785                                 break;
3786                         }
3787
3788                         // We don't know whether this function was called before
3789                         // or after moving the root page, so check both
3790                         // $this and $nt
3791                         if ( $oldSubpage->getArticleID() == $this->getArticleID()
3792                                 || $oldSubpage->getArticleID() == $nt->getArticleID()
3793                         ) {
3794                                 // When moving a page to a subpage of itself,
3795                                 // don't move it twice
3796                                 continue;
3797                         }
3798                         $newPageName = preg_replace(
3799                                         '#^' . preg_quote( $this->getDBkey(), '#' ) . '#',
3800                                         StringUtils::escapeRegexReplacement( $nt->getDBkey() ), # T23234
3801                                         $oldSubpage->getDBkey() );
3802                         if ( $oldSubpage->isTalkPage() ) {
3803                                 $newNs = $nt->getTalkPage()->getNamespace();
3804                         } else {
3805                                 $newNs = $nt->getSubjectPage()->getNamespace();
3806                         }
3807                         # T16385: we need makeTitleSafe because the new page names may
3808                         # be longer than 255 characters.
3809                         $newSubpage = Title::makeTitleSafe( $newNs, $newPageName );
3810
3811                         $success = $oldSubpage->moveTo( $newSubpage, $auth, $reason, $createRedirect, $changeTags );
3812                         if ( $success === true ) {
3813                                 $retval[$oldSubpage->getPrefixedText()] = $newSubpage->getPrefixedText();
3814                         } else {
3815                                 $retval[$oldSubpage->getPrefixedText()] = $success;
3816                         }
3817                 }
3818                 return $retval;
3819         }
3820
3821         /**
3822          * Checks if this page is just a one-rev redirect.
3823          * Adds lock, so don't use just for light purposes.
3824          *
3825          * @return bool
3826          */
3827         public function isSingleRevRedirect() {
3828                 global $wgContentHandlerUseDB;
3829
3830                 $dbw = wfGetDB( DB_MASTER );
3831
3832                 # Is it a redirect?
3833                 $fields = [ 'page_is_redirect', 'page_latest', 'page_id' ];
3834                 if ( $wgContentHandlerUseDB ) {
3835                         $fields[] = 'page_content_model';
3836                 }
3837
3838                 $row = $dbw->selectRow( 'page',
3839                         $fields,
3840                         $this->pageCond(),
3841                         __METHOD__,
3842                         [ 'FOR UPDATE' ]
3843                 );
3844                 # Cache some fields we may want
3845                 $this->mArticleID = $row ? intval( $row->page_id ) : 0;
3846                 $this->mRedirect = $row ? (bool)$row->page_is_redirect : false;
3847                 $this->mLatestID = $row ? intval( $row->page_latest ) : false;
3848                 $this->mContentModel = $row && isset( $row->page_content_model )
3849                         ? strval( $row->page_content_model )
3850                         : false;
3851
3852                 if ( !$this->mRedirect ) {
3853                         return false;
3854                 }
3855                 # Does the article have a history?
3856                 $row = $dbw->selectField( [ 'page', 'revision' ],
3857                         'rev_id',
3858                         [ 'page_namespace' => $this->getNamespace(),
3859                                 'page_title' => $this->getDBkey(),
3860                                 'page_id=rev_page',
3861                                 'page_latest != rev_id'
3862                         ],
3863                         __METHOD__,
3864                         [ 'FOR UPDATE' ]
3865                 );
3866                 # Return true if there was no history
3867                 return ( $row === false );
3868         }
3869
3870         /**
3871          * Checks if $this can be moved to a given Title
3872          * - Selects for update, so don't call it unless you mean business
3873          *
3874          * @deprecated since 1.25, use MovePage's methods instead
3875          * @param Title $nt The new title to check
3876          * @return bool
3877          */
3878         public function isValidMoveTarget( $nt ) {
3879                 # Is it an existing file?
3880                 if ( $nt->getNamespace() == NS_FILE ) {
3881                         $file = wfLocalFile( $nt );
3882                         $file->load( File::READ_LATEST );
3883                         if ( $file->exists() ) {
3884                                 wfDebug( __METHOD__ . ": file exists\n" );
3885                                 return false;
3886                         }
3887                 }
3888                 # Is it a redirect with no history?
3889                 if ( !$nt->isSingleRevRedirect() ) {
3890                         wfDebug( __METHOD__ . ": not a one-rev redirect\n" );
3891                         return false;
3892                 }
3893                 # Get the article text
3894                 $rev = Revision::newFromTitle( $nt, false, Revision::READ_LATEST );
3895                 if ( !is_object( $rev ) ) {
3896                         return false;
3897                 }
3898                 $content = $rev->getContent();
3899                 # Does the redirect point to the source?
3900                 # Or is it a broken self-redirect, usually caused by namespace collisions?
3901                 $redirTitle = $content ? $content->getRedirectTarget() : null;
3902
3903                 if ( $redirTitle ) {
3904                         if ( $redirTitle->getPrefixedDBkey() != $this->getPrefixedDBkey() &&
3905                                 $redirTitle->getPrefixedDBkey() != $nt->getPrefixedDBkey() ) {
3906                                 wfDebug( __METHOD__ . ": redirect points to other page\n" );
3907                                 return false;
3908                         } else {
3909                                 return true;
3910                         }
3911                 } else {
3912                         # Fail safe (not a redirect after all. strange.)
3913                         wfDebug( __METHOD__ . ": failsafe: database sais " . $nt->getPrefixedDBkey() .
3914                                                 " is a redirect, but it doesn't contain a valid redirect.\n" );
3915                         return false;
3916                 }
3917         }
3918
3919         /**
3920          * Get categories to which this Title belongs and return an array of
3921          * categories' names.
3922          *
3923          * @return array Array of parents in the form:
3924          *     $parent => $currentarticle
3925          */
3926         public function getParentCategories() {
3927                 global $wgContLang;
3928
3929                 $data = [];
3930
3931                 $titleKey = $this->getArticleID();
3932
3933                 if ( $titleKey === 0 ) {
3934                         return $data;
3935                 }
3936
3937                 $dbr = wfGetDB( DB_REPLICA );
3938
3939                 $res = $dbr->select(
3940                         'categorylinks',
3941                         'cl_to',
3942                         [ 'cl_from' => $titleKey ],
3943                         __METHOD__
3944                 );
3945
3946                 if ( $res->numRows() > 0 ) {
3947                         foreach ( $res as $row ) {
3948                                 // $data[] = Title::newFromText($wgContLang->getNsText ( NS_CATEGORY ).':'.$row->cl_to);
3949                                 $data[$wgContLang->getNsText( NS_CATEGORY ) . ':' . $row->cl_to] = $this->getFullText();
3950                         }
3951                 }
3952                 return $data;
3953         }
3954
3955         /**
3956          * Get a tree of parent categories
3957          *
3958          * @param array $children Array with the children in the keys, to check for circular refs
3959          * @return array Tree of parent categories
3960          */
3961         public function getParentCategoryTree( $children = [] ) {
3962                 $stack = [];
3963                 $parents = $this->getParentCategories();
3964
3965                 if ( $parents ) {
3966                         foreach ( $parents as $parent => $current ) {
3967                                 if ( array_key_exists( $parent, $children ) ) {
3968                                         # Circular reference
3969                                         $stack[$parent] = [];
3970                                 } else {
3971                                         $nt = Title::newFromText( $parent );
3972                                         if ( $nt ) {
3973                                                 $stack[$parent] = $nt->getParentCategoryTree( $children + [ $parent => 1 ] );
3974                                         }
3975                                 }
3976                         }
3977                 }
3978
3979                 return $stack;
3980         }
3981
3982         /**
3983          * Get an associative array for selecting this title from
3984          * the "page" table
3985          *
3986          * @return array Array suitable for the $where parameter of DB::select()
3987          */
3988         public function pageCond() {
3989                 if ( $this->mArticleID > 0 ) {
3990                         // PK avoids secondary lookups in InnoDB, shouldn't hurt other DBs
3991                         return [ 'page_id' => $this->mArticleID ];
3992                 } else {
3993                         return [ 'page_namespace' => $this->mNamespace, 'page_title' => $this->mDbkeyform ];
3994                 }
3995         }
3996
3997         /**
3998          * Get the revision ID of the previous revision
3999          *
4000          * @param int $revId Revision ID. Get the revision that was before this one.
4001          * @param int $flags Title::GAID_FOR_UPDATE
4002          * @return int|bool Old revision ID, or false if none exists
4003          */
4004         public function getPreviousRevisionID( $revId, $flags = 0 ) {
4005                 /* This function and getNextRevisionID have bad performance when
4006                    used on a page with many revisions on mysql. An explicit extended
4007                    primary key may help in some cases, if the PRIMARY KEY is banned:
4008                    T159319 */
4009                 if ( $flags & self::GAID_FOR_UPDATE ) {
4010                         $db = wfGetDB( DB_MASTER );
4011                 } else {
4012                         $db = wfGetDB( DB_REPLICA, 'contributions' );
4013                 }
4014                 $revId = $db->selectField( 'revision', 'rev_id',
4015                         [
4016                                 'rev_page' => $this->getArticleID( $flags ),
4017                                 'rev_id < ' . intval( $revId )
4018                         ],
4019                         __METHOD__,
4020                         [ 'ORDER BY' => 'rev_id DESC', 'IGNORE INDEX' => 'PRIMARY' ]
4021                 );
4022
4023                 if ( $revId === false ) {
4024                         return false;
4025                 } else {
4026                         return intval( $revId );
4027                 }
4028         }
4029
4030         /**
4031          * Get the revision ID of the next revision
4032          *
4033          * @param int $revId Revision ID. Get the revision that was after this one.
4034          * @param int $flags Title::GAID_FOR_UPDATE
4035          * @return int|bool Next revision ID, or false if none exists
4036          */
4037         public function getNextRevisionID( $revId, $flags = 0 ) {
4038                 if ( $flags & self::GAID_FOR_UPDATE ) {
4039                         $db = wfGetDB( DB_MASTER );
4040                 } else {
4041                         $db = wfGetDB( DB_REPLICA, 'contributions' );
4042                 }
4043                 $revId = $db->selectField( 'revision', 'rev_id',
4044                         [
4045                                 'rev_page' => $this->getArticleID( $flags ),
4046                                 'rev_id > ' . intval( $revId )
4047                         ],
4048                         __METHOD__,
4049                         [ 'ORDER BY' => 'rev_id', 'IGNORE INDEX' => 'PRIMARY' ]
4050                 );
4051
4052                 if ( $revId === false ) {
4053                         return false;
4054                 } else {
4055                         return intval( $revId );
4056                 }
4057         }
4058
4059         /**
4060          * Get the first revision of the page
4061          *
4062          * @param int $flags Title::GAID_FOR_UPDATE
4063          * @return Revision|null If page doesn't exist
4064          */
4065         public function getFirstRevision( $flags = 0 ) {
4066                 $pageId = $this->getArticleID( $flags );
4067                 if ( $pageId ) {
4068                         $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_REPLICA );
4069                         $row = $db->selectRow( 'revision', Revision::selectFields(),
4070                                 [ 'rev_page' => $pageId ],
4071                                 __METHOD__,
4072                                 [
4073                                         'ORDER BY' => 'rev_timestamp ASC',
4074                                         'IGNORE INDEX' => 'rev_timestamp'
4075                                 ]
4076                         );
4077                         if ( $row ) {
4078                                 return new Revision( $row );
4079                         }
4080                 }
4081                 return null;
4082         }
4083
4084         /**
4085          * Get the oldest revision timestamp of this page
4086          *
4087          * @param int $flags Title::GAID_FOR_UPDATE
4088          * @return string MW timestamp
4089          */
4090         public function getEarliestRevTime( $flags = 0 ) {
4091                 $rev = $this->getFirstRevision( $flags );
4092                 return $rev ? $rev->getTimestamp() : null;
4093         }
4094
4095         /**
4096          * Check if this is a new page
4097          *
4098          * @return bool
4099          */
4100         public function isNewPage() {
4101                 $dbr = wfGetDB( DB_REPLICA );
4102                 return (bool)$dbr->selectField( 'page', 'page_is_new', $this->pageCond(), __METHOD__ );
4103         }
4104
4105         /**
4106          * Check whether the number of revisions of this page surpasses $wgDeleteRevisionsLimit
4107          *
4108          * @return bool
4109          */
4110         public function isBigDeletion() {
4111                 global $wgDeleteRevisionsLimit;
4112
4113                 if ( !$wgDeleteRevisionsLimit ) {
4114                         return false;
4115                 }
4116
4117                 if ( $this->mIsBigDeletion === null ) {
4118                         $dbr = wfGetDB( DB_REPLICA );
4119
4120                         $revCount = $dbr->selectRowCount(
4121                                 'revision',
4122                                 '1',
4123                                 [ 'rev_page' => $this->getArticleID() ],
4124                                 __METHOD__,
4125                                 [ 'LIMIT' => $wgDeleteRevisionsLimit + 1 ]
4126                         );
4127
4128                         $this->mIsBigDeletion = $revCount > $wgDeleteRevisionsLimit;
4129                 }
4130
4131                 return $this->mIsBigDeletion;
4132         }
4133
4134         /**
4135          * Get the approximate revision count of this page.
4136          *
4137          * @return int
4138          */
4139         public function estimateRevisionCount() {
4140                 if ( !$this->exists() ) {
4141                         return 0;
4142                 }
4143
4144                 if ( $this->mEstimateRevisions === null ) {
4145                         $dbr = wfGetDB( DB_REPLICA );
4146                         $this->mEstimateRevisions = $dbr->estimateRowCount( 'revision', '*',
4147                                 [ 'rev_page' => $this->getArticleID() ], __METHOD__ );
4148                 }
4149
4150                 return $this->mEstimateRevisions;
4151         }
4152
4153         /**
4154          * Get the number of revisions between the given revision.
4155          * Used for diffs and other things that really need it.
4156          *
4157          * @param int|Revision $old Old revision or rev ID (first before range)
4158          * @param int|Revision $new New revision or rev ID (first after range)
4159          * @param int|null $max Limit of Revisions to count, will be incremented to detect truncations
4160          * @return int Number of revisions between these revisions.
4161          */
4162         public function countRevisionsBetween( $old, $new, $max = null ) {
4163                 if ( !( $old instanceof Revision ) ) {
4164                         $old = Revision::newFromTitle( $this, (int)$old );
4165                 }
4166                 if ( !( $new instanceof Revision ) ) {
4167                         $new = Revision::newFromTitle( $this, (int)$new );
4168                 }
4169                 if ( !$old || !$new ) {
4170                         return 0; // nothing to compare
4171                 }
4172                 $dbr = wfGetDB( DB_REPLICA );
4173                 $conds = [
4174                         'rev_page' => $this->getArticleID(),
4175                         'rev_timestamp > ' . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4176                         'rev_timestamp < ' . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4177                 ];
4178                 if ( $max !== null ) {
4179                         return $dbr->selectRowCount( 'revision', '1',
4180                                 $conds,
4181                                 __METHOD__,
4182                                 [ 'LIMIT' => $max + 1 ] // extra to detect truncation
4183                         );
4184                 } else {
4185                         return (int)$dbr->selectField( 'revision', 'count(*)', $conds, __METHOD__ );
4186                 }
4187         }
4188
4189         /**
4190          * Get the authors between the given revisions or revision IDs.
4191          * Used for diffs and other things that really need it.
4192          *
4193          * @since 1.23
4194          *
4195          * @param int|Revision $old Old revision or rev ID (first before range by default)
4196          * @param int|Revision $new New revision or rev ID (first after range by default)
4197          * @param int $limit Maximum number of authors
4198          * @param string|array $options (Optional): Single option, or an array of options:
4199          *     'include_old' Include $old in the range; $new is excluded.
4200          *     'include_new' Include $new in the range; $old is excluded.
4201          *     'include_both' Include both $old and $new in the range.
4202          *     Unknown option values are ignored.
4203          * @return array|null Names of revision authors in the range; null if not both revisions exist
4204          */
4205         public function getAuthorsBetween( $old, $new, $limit, $options = [] ) {
4206                 if ( !( $old instanceof Revision ) ) {
4207                         $old = Revision::newFromTitle( $this, (int)$old );
4208                 }
4209                 if ( !( $new instanceof Revision ) ) {
4210                         $new = Revision::newFromTitle( $this, (int)$new );
4211                 }
4212                 // XXX: what if Revision objects are passed in, but they don't refer to this title?
4213                 // Add $old->getPage() != $new->getPage() || $old->getPage() != $this->getArticleID()
4214                 // in the sanity check below?
4215                 if ( !$old || !$new ) {
4216                         return null; // nothing to compare
4217                 }
4218                 $authors = [];
4219                 $old_cmp = '>';
4220                 $new_cmp = '<';
4221                 $options = (array)$options;
4222                 if ( in_array( 'include_old', $options ) ) {
4223                         $old_cmp = '>=';
4224                 }
4225                 if ( in_array( 'include_new', $options ) ) {
4226                         $new_cmp = '<=';
4227                 }
4228                 if ( in_array( 'include_both', $options ) ) {
4229                         $old_cmp = '>=';
4230                         $new_cmp = '<=';
4231                 }
4232                 // No DB query needed if $old and $new are the same or successive revisions:
4233                 if ( $old->getId() === $new->getId() ) {
4234                         return ( $old_cmp === '>' && $new_cmp === '<' ) ?
4235                                 [] :
4236                                 [ $old->getUserText( Revision::RAW ) ];
4237                 } elseif ( $old->getId() === $new->getParentId() ) {
4238                         if ( $old_cmp === '>=' && $new_cmp === '<=' ) {
4239                                 $authors[] = $old->getUserText( Revision::RAW );
4240                                 if ( $old->getUserText( Revision::RAW ) != $new->getUserText( Revision::RAW ) ) {
4241                                         $authors[] = $new->getUserText( Revision::RAW );
4242                                 }
4243                         } elseif ( $old_cmp === '>=' ) {
4244                                 $authors[] = $old->getUserText( Revision::RAW );
4245                         } elseif ( $new_cmp === '<=' ) {
4246                                 $authors[] = $new->getUserText( Revision::RAW );
4247                         }
4248                         return $authors;
4249                 }
4250                 $dbr = wfGetDB( DB_REPLICA );
4251                 $res = $dbr->select( 'revision', 'DISTINCT rev_user_text',
4252                         [
4253                                 'rev_page' => $this->getArticleID(),
4254                                 "rev_timestamp $old_cmp " . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4255                                 "rev_timestamp $new_cmp " . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4256                         ], __METHOD__,
4257                         [ 'LIMIT' => $limit + 1 ] // add one so caller knows it was truncated
4258                 );
4259                 foreach ( $res as $row ) {
4260                         $authors[] = $row->rev_user_text;
4261                 }
4262                 return $authors;
4263         }
4264
4265         /**
4266          * Get the number of authors between the given revisions or revision IDs.
4267          * Used for diffs and other things that really need it.
4268          *
4269          * @param int|Revision $old Old revision or rev ID (first before range by default)
4270          * @param int|Revision $new New revision or rev ID (first after range by default)
4271          * @param int $limit Maximum number of authors
4272          * @param string|array $options (Optional): Single option, or an array of options:
4273          *     'include_old' Include $old in the range; $new is excluded.
4274          *     'include_new' Include $new in the range; $old is excluded.
4275          *     'include_both' Include both $old and $new in the range.
4276          *     Unknown option values are ignored.
4277          * @return int Number of revision authors in the range; zero if not both revisions exist
4278          */
4279         public function countAuthorsBetween( $old, $new, $limit, $options = [] ) {
4280                 $authors = $this->getAuthorsBetween( $old, $new, $limit, $options );
4281                 return $authors ? count( $authors ) : 0;
4282         }
4283
4284         /**
4285          * Compare with another title.
4286          *
4287          * @param Title $title
4288          * @return bool
4289          */
4290         public function equals( Title $title ) {
4291                 // Note: === is necessary for proper matching of number-like titles.
4292                 return $this->getInterwiki() === $title->getInterwiki()
4293                         && $this->getNamespace() == $title->getNamespace()
4294                         && $this->getDBkey() === $title->getDBkey();
4295         }
4296
4297         /**
4298          * Check if this title is a subpage of another title
4299          *
4300          * @param Title $title
4301          * @return bool
4302          */
4303         public function isSubpageOf( Title $title ) {
4304                 return $this->getInterwiki() === $title->getInterwiki()
4305                         && $this->getNamespace() == $title->getNamespace()
4306                         && strpos( $this->getDBkey(), $title->getDBkey() . '/' ) === 0;
4307         }
4308
4309         /**
4310          * Check if page exists.  For historical reasons, this function simply
4311          * checks for the existence of the title in the page table, and will
4312          * thus return false for interwiki links, special pages and the like.
4313          * If you want to know if a title can be meaningfully viewed, you should
4314          * probably call the isKnown() method instead.
4315          *
4316          * @param int $flags An optional bit field; may be Title::GAID_FOR_UPDATE to check
4317          *   from master/for update
4318          * @return bool
4319          */
4320         public function exists( $flags = 0 ) {
4321                 $exists = $this->getArticleID( $flags ) != 0;
4322                 Hooks::run( 'TitleExists', [ $this, &$exists ] );
4323                 return $exists;
4324         }
4325
4326         /**
4327          * Should links to this title be shown as potentially viewable (i.e. as
4328          * "bluelinks"), even if there's no record by this title in the page
4329          * table?
4330          *
4331          * This function is semi-deprecated for public use, as well as somewhat
4332          * misleadingly named.  You probably just want to call isKnown(), which
4333          * calls this function internally.
4334          *
4335          * (ISSUE: Most of these checks are cheap, but the file existence check
4336          * can potentially be quite expensive.  Including it here fixes a lot of
4337          * existing code, but we might want to add an optional parameter to skip
4338          * it and any other expensive checks.)
4339          *
4340          * @return bool
4341          */
4342         public function isAlwaysKnown() {
4343                 $isKnown = null;
4344
4345                 /**
4346                  * Allows overriding default behavior for determining if a page exists.
4347                  * If $isKnown is kept as null, regular checks happen. If it's
4348                  * a boolean, this value is returned by the isKnown method.
4349                  *
4350                  * @since 1.20
4351                  *
4352                  * @param Title $title
4353                  * @param bool|null $isKnown
4354                  */
4355                 Hooks::run( 'TitleIsAlwaysKnown', [ $this, &$isKnown ] );
4356
4357                 if ( !is_null( $isKnown ) ) {
4358                         return $isKnown;
4359                 }
4360
4361                 if ( $this->isExternal() ) {
4362                         return true;  // any interwiki link might be viewable, for all we know
4363                 }
4364
4365                 switch ( $this->mNamespace ) {
4366                         case NS_MEDIA:
4367                         case NS_FILE:
4368                                 // file exists, possibly in a foreign repo
4369                                 return (bool)wfFindFile( $this );
4370                         case NS_SPECIAL:
4371                                 // valid special page
4372                                 return SpecialPageFactory::exists( $this->getDBkey() );
4373                         case NS_MAIN:
4374                                 // selflink, possibly with fragment
4375                                 return $this->mDbkeyform == '';
4376                         case NS_MEDIAWIKI:
4377                                 // known system message
4378                                 return $this->hasSourceText() !== false;
4379                         default:
4380                                 return false;
4381                 }
4382         }
4383
4384         /**
4385          * Does this title refer to a page that can (or might) be meaningfully
4386          * viewed?  In particular, this function may be used to determine if
4387          * links to the title should be rendered as "bluelinks" (as opposed to
4388          * "redlinks" to non-existent pages).
4389          * Adding something else to this function will cause inconsistency
4390          * since LinkHolderArray calls isAlwaysKnown() and does its own
4391          * page existence check.
4392          *
4393          * @return bool
4394          */
4395         public function isKnown() {
4396                 return $this->isAlwaysKnown() || $this->exists();
4397         }
4398
4399         /**
4400          * Does this page have source text?
4401          *
4402          * @return bool
4403          */
4404         public function hasSourceText() {
4405                 if ( $this->exists() ) {
4406                         return true;
4407                 }
4408
4409                 if ( $this->mNamespace == NS_MEDIAWIKI ) {
4410                         // If the page doesn't exist but is a known system message, default
4411                         // message content will be displayed, same for language subpages-
4412                         // Use always content language to avoid loading hundreds of languages
4413                         // to get the link color.
4414                         global $wgContLang;
4415                         list( $name, ) = MessageCache::singleton()->figureMessage(
4416                                 $wgContLang->lcfirst( $this->getText() )
4417                         );
4418                         $message = wfMessage( $name )->inLanguage( $wgContLang )->useDatabase( false );
4419                         return $message->exists();
4420                 }
4421
4422                 return false;
4423         }
4424
4425         /**
4426          * Get the default message text or false if the message doesn't exist
4427          *
4428          * @return string|bool
4429          */
4430         public function getDefaultMessageText() {
4431                 global $wgContLang;
4432
4433                 if ( $this->getNamespace() != NS_MEDIAWIKI ) { // Just in case
4434                         return false;
4435                 }
4436
4437                 list( $name, $lang ) = MessageCache::singleton()->figureMessage(
4438                         $wgContLang->lcfirst( $this->getText() )
4439                 );
4440                 $message = wfMessage( $name )->inLanguage( $lang )->useDatabase( false );
4441
4442                 if ( $message->exists() ) {
4443                         return $message->plain();
4444                 } else {
4445                         return false;
4446                 }
4447         }
4448
4449         /**
4450          * Updates page_touched for this page; called from LinksUpdate.php
4451          *
4452          * @param string $purgeTime [optional] TS_MW timestamp
4453          * @return bool True if the update succeeded
4454          */
4455         public function invalidateCache( $purgeTime = null ) {
4456                 if ( wfReadOnly() ) {
4457                         return false;
4458                 } elseif ( $this->mArticleID === 0 ) {
4459                         return true; // avoid gap locking if we know it's not there
4460                 }
4461
4462                 $dbw = wfGetDB( DB_MASTER );
4463                 $dbw->onTransactionPreCommitOrIdle( function () {
4464                         ResourceLoaderWikiModule::invalidateModuleCache( $this, null, null, wfWikiID() );
4465                 } );
4466
4467                 $conds = $this->pageCond();
4468                 DeferredUpdates::addUpdate(
4469                         new AutoCommitUpdate(
4470                                 $dbw,
4471                                 __METHOD__,
4472                                 function ( IDatabase $dbw, $fname ) use ( $conds, $purgeTime ) {
4473                                         $dbTimestamp = $dbw->timestamp( $purgeTime ?: time() );
4474                                         $dbw->update(
4475                                                 'page',
4476                                                 [ 'page_touched' => $dbTimestamp ],
4477                                                 $conds + [ 'page_touched < ' . $dbw->addQuotes( $dbTimestamp ) ],
4478                                                 $fname
4479                                         );
4480                                         MediaWikiServices::getInstance()->getLinkCache()->invalidateTitle( $this );
4481                                 }
4482                         ),
4483                         DeferredUpdates::PRESEND
4484                 );
4485
4486                 return true;
4487         }
4488
4489         /**
4490          * Update page_touched timestamps and send CDN purge messages for
4491          * pages linking to this title. May be sent to the job queue depending
4492          * on the number of links. Typically called on create and delete.
4493          */
4494         public function touchLinks() {
4495                 DeferredUpdates::addUpdate( new HTMLCacheUpdate( $this, 'pagelinks' ) );
4496                 if ( $this->getNamespace() == NS_CATEGORY ) {
4497                         DeferredUpdates::addUpdate( new HTMLCacheUpdate( $this, 'categorylinks' ) );
4498                 }
4499         }
4500
4501         /**
4502          * Get the last touched timestamp
4503          *
4504          * @param IDatabase $db Optional db
4505          * @return string|false Last-touched timestamp
4506          */
4507         public function getTouched( $db = null ) {
4508                 if ( $db === null ) {
4509                         $db = wfGetDB( DB_REPLICA );
4510                 }
4511                 $touched = $db->selectField( 'page', 'page_touched', $this->pageCond(), __METHOD__ );
4512                 return $touched;
4513         }
4514
4515         /**
4516          * Get the timestamp when this page was updated since the user last saw it.
4517          *
4518          * @param User $user
4519          * @return string|null
4520          */
4521         public function getNotificationTimestamp( $user = null ) {
4522                 global $wgUser;
4523
4524                 // Assume current user if none given
4525                 if ( !$user ) {
4526                         $user = $wgUser;
4527                 }
4528                 // Check cache first
4529                 $uid = $user->getId();
4530                 if ( !$uid ) {
4531                         return false;
4532                 }
4533                 // avoid isset here, as it'll return false for null entries
4534                 if ( array_key_exists( $uid, $this->mNotificationTimestamp ) ) {
4535                         return $this->mNotificationTimestamp[$uid];
4536                 }
4537                 // Don't cache too much!
4538                 if ( count( $this->mNotificationTimestamp ) >= self::CACHE_MAX ) {
4539                         $this->mNotificationTimestamp = [];
4540                 }
4541
4542                 $store = MediaWikiServices::getInstance()->getWatchedItemStore();
4543                 $watchedItem = $store->getWatchedItem( $user, $this );
4544                 if ( $watchedItem ) {
4545                         $this->mNotificationTimestamp[$uid] = $watchedItem->getNotificationTimestamp();
4546                 } else {
4547                         $this->mNotificationTimestamp[$uid] = false;
4548                 }
4549
4550                 return $this->mNotificationTimestamp[$uid];
4551         }
4552
4553         /**
4554          * Generate strings used for xml 'id' names in monobook tabs
4555          *
4556          * @param string $prepend Defaults to 'nstab-'
4557          * @return string XML 'id' name
4558          */
4559         public function getNamespaceKey( $prepend = 'nstab-' ) {
4560                 global $wgContLang;
4561                 // Gets the subject namespace if this title
4562                 $namespace = MWNamespace::getSubject( $this->getNamespace() );
4563                 // Checks if canonical namespace name exists for namespace
4564                 if ( MWNamespace::exists( $this->getNamespace() ) ) {
4565                         // Uses canonical namespace name
4566                         $namespaceKey = MWNamespace::getCanonicalName( $namespace );
4567                 } else {
4568                         // Uses text of namespace
4569                         $namespaceKey = $this->getSubjectNsText();
4570                 }
4571                 // Makes namespace key lowercase
4572                 $namespaceKey = $wgContLang->lc( $namespaceKey );
4573                 // Uses main
4574                 if ( $namespaceKey == '' ) {
4575                         $namespaceKey = 'main';
4576                 }
4577                 // Changes file to image for backwards compatibility
4578                 if ( $namespaceKey == 'file' ) {
4579                         $namespaceKey = 'image';
4580                 }
4581                 return $prepend . $namespaceKey;
4582         }
4583
4584         /**
4585          * Get all extant redirects to this Title
4586          *
4587          * @param int|null $ns Single namespace to consider; null to consider all namespaces
4588          * @return Title[] Array of Title redirects to this title
4589          */
4590         public function getRedirectsHere( $ns = null ) {
4591                 $redirs = [];
4592
4593                 $dbr = wfGetDB( DB_REPLICA );
4594                 $where = [
4595                         'rd_namespace' => $this->getNamespace(),
4596                         'rd_title' => $this->getDBkey(),
4597                         'rd_from = page_id'
4598                 ];
4599                 if ( $this->isExternal() ) {
4600                         $where['rd_interwiki'] = $this->getInterwiki();
4601                 } else {
4602                         $where[] = 'rd_interwiki = ' . $dbr->addQuotes( '' ) . ' OR rd_interwiki IS NULL';
4603                 }
4604                 if ( !is_null( $ns ) ) {
4605                         $where['page_namespace'] = $ns;
4606                 }
4607
4608                 $res = $dbr->select(
4609                         [ 'redirect', 'page' ],
4610                         [ 'page_namespace', 'page_title' ],
4611                         $where,
4612                         __METHOD__
4613                 );
4614
4615                 foreach ( $res as $row ) {
4616                         $redirs[] = self::newFromRow( $row );
4617                 }
4618                 return $redirs;
4619         }
4620
4621         /**
4622          * Check if this Title is a valid redirect target
4623          *
4624          * @return bool
4625          */
4626         public function isValidRedirectTarget() {
4627                 global $wgInvalidRedirectTargets;
4628
4629                 if ( $this->isSpecialPage() ) {
4630                         // invalid redirect targets are stored in a global array, but explicitly disallow Userlogout here
4631                         if ( $this->isSpecial( 'Userlogout' ) ) {
4632                                 return false;
4633                         }
4634
4635                         foreach ( $wgInvalidRedirectTargets as $target ) {
4636                                 if ( $this->isSpecial( $target ) ) {
4637                                         return false;
4638                                 }
4639                         }
4640                 }
4641
4642                 return true;
4643         }
4644
4645         /**
4646          * Get a backlink cache object
4647          *
4648          * @return BacklinkCache
4649          */
4650         public function getBacklinkCache() {
4651                 return BacklinkCache::get( $this );
4652         }
4653
4654         /**
4655          * Whether the magic words __INDEX__ and __NOINDEX__ function for  this page.
4656          *
4657          * @return bool
4658          */
4659         public function canUseNoindex() {
4660                 global $wgExemptFromUserRobotsControl;
4661
4662                 $bannedNamespaces = is_null( $wgExemptFromUserRobotsControl )
4663                         ? MWNamespace::getContentNamespaces()
4664                         : $wgExemptFromUserRobotsControl;
4665
4666                 return !in_array( $this->mNamespace, $bannedNamespaces );
4667         }
4668
4669         /**
4670          * Returns the raw sort key to be used for categories, with the specified
4671          * prefix.  This will be fed to Collation::getSortKey() to get a
4672          * binary sortkey that can be used for actual sorting.
4673          *
4674          * @param string $prefix The prefix to be used, specified using
4675          *   {{defaultsort:}} or like [[Category:Foo|prefix]].  Empty for no
4676          *   prefix.
4677          * @return string
4678          */
4679         public function getCategorySortkey( $prefix = '' ) {
4680                 $unprefixed = $this->getText();
4681
4682                 // Anything that uses this hook should only depend
4683                 // on the Title object passed in, and should probably
4684                 // tell the users to run updateCollations.php --force
4685                 // in order to re-sort existing category relations.
4686                 Hooks::run( 'GetDefaultSortkey', [ $this, &$unprefixed ] );
4687                 if ( $prefix !== '' ) {
4688                         # Separate with a line feed, so the unprefixed part is only used as
4689                         # a tiebreaker when two pages have the exact same prefix.
4690                         # In UCA, tab is the only character that can sort above LF
4691                         # so we strip both of them from the original prefix.
4692                         $prefix = strtr( $prefix, "\n\t", '  ' );
4693                         return "$prefix\n$unprefixed";
4694                 }
4695                 return $unprefixed;
4696         }
4697
4698         /**
4699          * Returns the page language code saved in the database, if $wgPageLanguageUseDB is set
4700          * to true in LocalSettings.php, otherwise returns false. If there is no language saved in
4701          * the db, it will return NULL.
4702          *
4703          * @return string|null|bool
4704          */
4705         private function getDbPageLanguageCode() {
4706                 global $wgPageLanguageUseDB;
4707
4708                 // check, if the page language could be saved in the database, and if so and
4709                 // the value is not requested already, lookup the page language using LinkCache
4710                 if ( $wgPageLanguageUseDB && $this->mDbPageLanguage === false ) {
4711                         $linkCache = LinkCache::singleton();
4712                         $linkCache->addLinkObj( $this );
4713                         $this->mDbPageLanguage = $linkCache->getGoodLinkFieldObj( $this, 'lang' );
4714                 }
4715
4716                 return $this->mDbPageLanguage;
4717         }
4718
4719         /**
4720          * Get the language in which the content of this page is written in
4721          * wikitext. Defaults to $wgContLang, but in certain cases it can be
4722          * e.g. $wgLang (such as special pages, which are in the user language).
4723          *
4724          * @since 1.18
4725          * @return Language
4726          */
4727         public function getPageLanguage() {
4728                 global $wgLang, $wgLanguageCode;
4729                 if ( $this->isSpecialPage() ) {
4730                         // special pages are in the user language
4731                         return $wgLang;
4732                 }
4733
4734                 // Checking if DB language is set
4735                 $dbPageLanguage = $this->getDbPageLanguageCode();
4736                 if ( $dbPageLanguage ) {
4737                         return wfGetLangObj( $dbPageLanguage );
4738                 }
4739
4740                 if ( !$this->mPageLanguage || $this->mPageLanguage[1] !== $wgLanguageCode ) {
4741                         // Note that this may depend on user settings, so the cache should
4742                         // be only per-request.
4743                         // NOTE: ContentHandler::getPageLanguage() may need to load the
4744                         // content to determine the page language!
4745                         // Checking $wgLanguageCode hasn't changed for the benefit of unit
4746                         // tests.
4747                         $contentHandler = ContentHandler::getForTitle( $this );
4748                         $langObj = $contentHandler->getPageLanguage( $this );
4749                         $this->mPageLanguage = [ $langObj->getCode(), $wgLanguageCode ];
4750                 } else {
4751                         $langObj = wfGetLangObj( $this->mPageLanguage[0] );
4752                 }
4753
4754                 return $langObj;
4755         }
4756
4757         /**
4758          * Get the language in which the content of this page is written when
4759          * viewed by user. Defaults to $wgContLang, but in certain cases it can be
4760          * e.g. $wgLang (such as special pages, which are in the user language).
4761          *
4762          * @since 1.20
4763          * @return Language
4764          */
4765         public function getPageViewLanguage() {
4766                 global $wgLang;
4767
4768                 if ( $this->isSpecialPage() ) {
4769                         // If the user chooses a variant, the content is actually
4770                         // in a language whose code is the variant code.
4771                         $variant = $wgLang->getPreferredVariant();
4772                         if ( $wgLang->getCode() !== $variant ) {
4773                                 return Language::factory( $variant );
4774                         }
4775
4776                         return $wgLang;
4777                 }
4778
4779                 // Checking if DB language is set
4780                 $dbPageLanguage = $this->getDbPageLanguageCode();
4781                 if ( $dbPageLanguage ) {
4782                         $pageLang = wfGetLangObj( $dbPageLanguage );
4783                         $variant = $pageLang->getPreferredVariant();
4784                         if ( $pageLang->getCode() !== $variant ) {
4785                                 $pageLang = Language::factory( $variant );
4786                         }
4787
4788                         return $pageLang;
4789                 }
4790
4791                 // @note Can't be cached persistently, depends on user settings.
4792                 // @note ContentHandler::getPageViewLanguage() may need to load the
4793                 //   content to determine the page language!
4794                 $contentHandler = ContentHandler::getForTitle( $this );
4795                 $pageLang = $contentHandler->getPageViewLanguage( $this );
4796                 return $pageLang;
4797         }
4798
4799         /**
4800          * Get a list of rendered edit notices for this page.
4801          *
4802          * Array is keyed by the original message key, and values are rendered using parseAsBlock, so
4803          * they will already be wrapped in paragraphs.
4804          *
4805          * @since 1.21
4806          * @param int $oldid Revision ID that's being edited
4807          * @return array
4808          */
4809         public function getEditNotices( $oldid = 0 ) {
4810                 $notices = [];
4811
4812                 // Optional notice for the entire namespace
4813                 $editnotice_ns = 'editnotice-' . $this->getNamespace();
4814                 $msg = wfMessage( $editnotice_ns );
4815                 if ( $msg->exists() ) {
4816                         $html = $msg->parseAsBlock();
4817                         // Edit notices may have complex logic, but output nothing (T91715)
4818                         if ( trim( $html ) !== '' ) {
4819                                 $notices[$editnotice_ns] = Html::rawElement(
4820                                         'div',
4821                                         [ 'class' => [
4822                                                 'mw-editnotice',
4823                                                 'mw-editnotice-namespace',
4824                                                 Sanitizer::escapeClass( "mw-$editnotice_ns" )
4825                                         ] ],
4826                                         $html
4827                                 );
4828                         }
4829                 }
4830
4831                 if ( MWNamespace::hasSubpages( $this->getNamespace() ) ) {
4832                         // Optional notice for page itself and any parent page
4833                         $parts = explode( '/', $this->getDBkey() );
4834                         $editnotice_base = $editnotice_ns;
4835                         while ( count( $parts ) > 0 ) {
4836                                 $editnotice_base .= '-' . array_shift( $parts );
4837                                 $msg = wfMessage( $editnotice_base );
4838                                 if ( $msg->exists() ) {
4839                                         $html = $msg->parseAsBlock();
4840                                         if ( trim( $html ) !== '' ) {
4841                                                 $notices[$editnotice_base] = Html::rawElement(
4842                                                         'div',
4843                                                         [ 'class' => [
4844                                                                 'mw-editnotice',
4845                                                                 'mw-editnotice-base',
4846                                                                 Sanitizer::escapeClass( "mw-$editnotice_base" )
4847                                                         ] ],
4848                                                         $html
4849                                                 );
4850                                         }
4851                                 }
4852                         }
4853                 } else {
4854                         // Even if there are no subpages in namespace, we still don't want "/" in MediaWiki message keys
4855                         $editnoticeText = $editnotice_ns . '-' . strtr( $this->getDBkey(), '/', '-' );
4856                         $msg = wfMessage( $editnoticeText );
4857                         if ( $msg->exists() ) {
4858                                 $html = $msg->parseAsBlock();
4859                                 if ( trim( $html ) !== '' ) {
4860                                         $notices[$editnoticeText] = Html::rawElement(
4861                                                 'div',
4862                                                 [ 'class' => [
4863                                                         'mw-editnotice',
4864                                                         'mw-editnotice-page',
4865                                                         Sanitizer::escapeClass( "mw-$editnoticeText" )
4866                                                 ] ],
4867                                                 $html
4868                                         );
4869                                 }
4870                         }
4871                 }
4872
4873                 Hooks::run( 'TitleGetEditNotices', [ $this, $oldid, &$notices ] );
4874                 return $notices;
4875         }
4876
4877         /**
4878          * @return array
4879          */
4880         public function __sleep() {
4881                 return [
4882                         'mNamespace',
4883                         'mDbkeyform',
4884                         'mFragment',
4885                         'mInterwiki',
4886                         'mLocalInterwiki',
4887                         'mUserCaseDBKey',
4888                         'mDefaultNamespace',
4889                 ];
4890         }
4891
4892         public function __wakeup() {
4893                 $this->mArticleID = ( $this->mNamespace >= 0 ) ? -1 : 0;
4894                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
4895                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
4896         }
4897
4898 }