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 use MediaWiki\Linker\LinkTarget;
  25 use MediaWiki\MediaWikiServices;
  26
  27 /**
  28  * Represents a title within MediaWiki.
  29  * Optionally may contain an interwiki designation or namespace.
  30  * @note This class can fetch various kinds of data from the database;
  31  *       however, it does so inefficiently.
  32  * @note Consider using a TitleValue object instead. TitleValue is more lightweight
  33  *       and does not rely on global state or the database.
  34  */
  35 class Title implements LinkTarget {
  36         /** @var HashBagOStuff */
  37         static private $titleCache = null;
  38
  39         /**
  40          * Title::newFromText maintains a cache to avoid expensive re-normalization of
  41          * commonly used titles. On a batch operation this can become a memory leak
  42          * if not bounded. After hitting this many titles reset the cache.
  43          */
  44         const CACHE_MAX = 1000;
  45
  46         /**
  47          * Used to be GAID_FOR_UPDATE define. Used with getArticleID() and friends
  48          * to use the master DB
  49          */
  50         const GAID_FOR_UPDATE = 1;
  51
  52         /**
  53          * @name Private member variables
  54          * Please use the accessor functions instead.
  55          * @private
  56          */
  57         // @{
  58
  59         /** @var string Text form (spaces not underscores) of the main part */
  60         public $mTextform = '';
  61
  62         /** @var string URL-encoded form of the main part */
  63         public $mUrlform = '';
  64
  65         /** @var string Main part with underscores */
  66         public $mDbkeyform = '';
  67
  68         /** @var string Database key with the initial letter in the case specified by the user */
  69         protected $mUserCaseDBKey;
  70
  71         /** @var int Namespace index, i.e. one of the NS_xxxx constants */
  72         public $mNamespace = NS_MAIN;
  73
  74         /** @var string Interwiki prefix */
  75         public $mInterwiki = '';
  76
  77         /** @var bool Was this Title created from a string with a local interwiki prefix? */
  78         private $mLocalInterwiki = false;
  79
  80         /** @var string Title fragment (i.e. the bit after the #) */
  81         public $mFragment = '';
  82
  83         /** @var int Article ID, fetched from the link cache on demand */
  84         public $mArticleID = -1;
  85
  86         /** @var bool|int ID of most recent revision */
  87         protected $mLatestID = false;
  88
  89         /**
  90          * @var bool|string ID of the page's content model, i.e. one of the
  91          *   CONTENT_MODEL_XXX constants
  92          */
  93         public $mContentModel = false;
  94
  95         /** @var int Estimated number of revisions; null of not loaded */
  96         private $mEstimateRevisions;
  97
  98         /** @var array Array of groups allowed to edit this article */
  99         public $mRestrictions = [];
 100
 101         /** @var string|bool */
 102         protected $mOldRestrictions = false;
 103
 104         /** @var bool Cascade restrictions on this page to included templates and images? */
 105         public $mCascadeRestriction;
 106
 107         /** Caching the results of getCascadeProtectionSources */
 108         public $mCascadingRestrictions;
 109
 110         /** @var array When do the restrictions on this page expire? */
 111         protected $mRestrictionsExpiry = [];
 112
 113         /** @var bool Are cascading restrictions in effect on this page? */
 114         protected $mHasCascadingRestrictions;
 115
 116         /** @var array Where are the cascading restrictions coming from on this page? */
 117         public $mCascadeSources;
 118
 119         /** @var bool Boolean for initialisation on demand */
 120         public $mRestrictionsLoaded = false;
 121
 122         /** @var string Text form including namespace/interwiki, initialised on demand */
 123         protected $mPrefixedText = null;
 124
 125         /** @var mixed Cached value for getTitleProtection (create protection) */
 126         public $mTitleProtection;
 127
 128         /**
 129          * @var int Namespace index when there is no namespace. Don't change the
 130          *   following default, NS_MAIN is hardcoded in several places. See bug 696.
 131          *   Zero except in {{transclusion}} tags.
 132          */
 133         public $mDefaultNamespace = NS_MAIN;
 134
 135         /** @var int The page length, 0 for special pages */
 136         protected $mLength = -1;
 137
 138         /** @var null Is the article at this title a redirect? */
 139         public $mRedirect = null;
 140
 141         /** @var array Associative array of user ID -> timestamp/false */
 142         private $mNotificationTimestamp = [];
 143
 144         /** @var bool Whether a page has any subpages */
 145         private $mHasSubpages;
 146
 147         /** @var bool The (string) language code of the page's language and content code. */
 148         private $mPageLanguage = false;
 149
 150         /** @var string|bool|null The page language code from the database, null if not saved in
 151          * the database or false if not loaded, yet. */
 152         private $mDbPageLanguage = false;
 153
 154         /** @var TitleValue A corresponding TitleValue object */
 155         private $mTitleValue = null;
 156
 157         /** @var bool Would deleting this page be a big deletion? */
 158         private $mIsBigDeletion = null;
 159         // @}
 160
 161         /**
 162          * B/C kludge: provide a TitleParser for use by Title.
 163          * Ideally, Title would have no methods that need this.
 164          * Avoid usage of this singleton by using TitleValue
 165          * and the associated services when possible.
 166          *
 167          * @return TitleFormatter
 168          */
 169         private static function getTitleFormatter() {
 170                 return MediaWikiServices::getInstance()->getTitleFormatter();
 171         }
 172
 173         /**
 174          * @access protected
 175          */
 176         function __construct() {
 177         }
 178
 179         /**
 180          * Create a new Title from a prefixed DB key
 181          *
 182          * @param string $key The database key, which has underscores
 183          *      instead of spaces, possibly including namespace and
 184          *      interwiki prefixes
 185          * @return Title|null Title, or null on an error
 186          */
 187         public static function newFromDBkey( $key ) {
 188                 $t = new Title();
 189                 $t->mDbkeyform = $key;
 190
 191                 try {
 192                         $t->secureAndSplit();
 193                         return $t;
 194                 } catch ( MalformedTitleException $ex ) {
 195                         return null;
 196                 }
 197         }
 198
 199         /**
 200          * Create a new Title from a TitleValue
 201          *
 202          * @param TitleValue $titleValue Assumed to be safe.
 203          *
 204          * @return Title
 205          */
 206         public static function newFromTitleValue( TitleValue $titleValue ) {
 207                 return self::newFromLinkTarget( $titleValue );
 208         }
 209
 210         /**
 211          * Create a new Title from a LinkTarget
 212          *
 213          * @param LinkTarget $linkTarget Assumed to be safe.
 214          *
 215          * @return Title
 216          */
 217         public static function newFromLinkTarget( LinkTarget $linkTarget ) {
 218                 if ( $linkTarget instanceof Title ) {
 219                         // Special case if it's already a Title object
 220                         return $linkTarget;
 221                 }
 222                 return self::makeTitle(
 223                         $linkTarget->getNamespace(),
 224                         $linkTarget->getText(),
 225                         $linkTarget->getFragment(),
 226                         $linkTarget->getInterwiki()
 227                 );
 228         }
 229
 230         /**
 231          * Create a new Title from text, such as what one would find in a link. De-
 232          * codes any HTML entities in the text.
 233          *
 234          * @param string|int|null $text The link text; spaces, prefixes, and an
 235          *   initial ':' indicating the main namespace are accepted.
 236          * @param int $defaultNamespace The namespace to use if none is specified
 237          *   by a prefix.  If you want to force a specific namespace even if
 238          *   $text might begin with a namespace prefix, use makeTitle() or
 239          *   makeTitleSafe().
 240          * @throws InvalidArgumentException
 241          * @return Title|null Title or null on an error.
 242          */
 243         public static function newFromText( $text, $defaultNamespace = NS_MAIN ) {
 244                 // DWIM: Integers can be passed in here when page titles are used as array keys.
 245                 if ( $text !== null && !is_string( $text ) && !is_int( $text ) ) {
 246                         throw new InvalidArgumentException( '$text must be a string.' );
 247                 }
 248                 if ( $text === null ) {
 249                         return null;
 250                 }
 251
 252                 try {
 253                         return Title::newFromTextThrow( strval( $text ), $defaultNamespace );
 254                 } catch ( MalformedTitleException $ex ) {
 255                         return null;
 256                 }
 257         }
 258
 259         /**
 260          * Like Title::newFromText(), but throws MalformedTitleException when the title is invalid,
 261          * rather than returning null.
 262          *
 263          * The exception subclasses encode detailed information about why the title is invalid.
 264          *
 265          * @see Title::newFromText
 266          *
 267          * @since 1.25
 268          * @param string $text Title text to check
 269          * @param int $defaultNamespace
 270          * @throws MalformedTitleException If the title is invalid
 271          * @return Title
 272          */
 273         public static function newFromTextThrow( $text, $defaultNamespace = NS_MAIN ) {
 274                 if ( is_object( $text ) ) {
 275                         throw new MWException( '$text must be a string, given an object' );
 276                 }
 277
 278                 $titleCache = self::getTitleCache();
 279
 280                 // Wiki pages often contain multiple links to the same page.
 281                 // Title normalization and parsing can become expensive on pages with many
 282                 // links, so we can save a little time by caching them.
 283                 // In theory these are value objects and won't get changed...
 284                 if ( $defaultNamespace == NS_MAIN ) {
 285                         $t = $titleCache->get( $text );
 286                         if ( $t ) {
 287                                 return $t;
 288                         }
 289                 }
 290
 291                 // Convert things like &eacute; &#257; or &#x3017; into normalized (bug 14952) text
 292                 $filteredText = Sanitizer::decodeCharReferencesAndNormalize( $text );
 293
 294                 $t = new Title();
 295                 $t->mDbkeyform = strtr( $filteredText, ' ', '_' );
 296                 $t->mDefaultNamespace = intval( $defaultNamespace );
 297
 298                 $t->secureAndSplit();
 299                 if ( $defaultNamespace == NS_MAIN ) {
 300                         $titleCache->set( $text, $t );
 301                 }
 302                 return $t;
 303         }
 304
 305         /**
 306          * THIS IS NOT THE FUNCTION YOU WANT. Use Title::newFromText().
 307          *
 308          * Example of wrong and broken code:
 309          * $title = Title::newFromURL( $wgRequest->getVal( 'title' ) );
 310          *
 311          * Example of right code:
 312          * $title = Title::newFromText( $wgRequest->getVal( 'title' ) );
 313          *
 314          * Create a new Title from URL-encoded text. Ensures that
 315          * the given title's length does not exceed the maximum.
 316          *
 317          * @param string $url The title, as might be taken from a URL
 318          * @return Title|null The new object, or null on an error
 319          */
 320         public static function newFromURL( $url ) {
 321                 $t = new Title();
 322
 323                 # For compatibility with old buggy URLs. "+" is usually not valid in titles,
 324                 # but some URLs used it as a space replacement and they still come
 325                 # from some external search tools.
 326                 if ( strpos( self::legalChars(), '+' ) === false ) {
 327                         $url = strtr( $url, '+', ' ' );
 328                 }
 329
 330                 $t->mDbkeyform = strtr( $url, ' ', '_' );
 331
 332                 try {
 333                         $t->secureAndSplit();
 334                         return $t;
 335                 } catch ( MalformedTitleException $ex ) {
 336                         return null;
 337                 }
 338         }
 339
 340         /**
 341          * @return HashBagOStuff
 342          */
 343         private static function getTitleCache() {
 344                 if ( self::$titleCache == null ) {
 345                         self::$titleCache = new HashBagOStuff( [ 'maxKeys' => self::CACHE_MAX ] );
 346                 }
 347                 return self::$titleCache;
 348         }
 349
 350         /**
 351          * Returns a list of fields that are to be selected for initializing Title
 352          * objects or LinkCache entries. Uses $wgContentHandlerUseDB to determine
 353          * whether to include page_content_model.
 354          *
 355          * @return array
 356          */
 357         protected static function getSelectFields() {
 358                 global $wgContentHandlerUseDB, $wgPageLanguageUseDB;
 359
 360                 $fields = [
 361                         'page_namespace', 'page_title', 'page_id',
 362                         'page_len', 'page_is_redirect', 'page_latest',
 363                 ];
 364
 365                 if ( $wgContentHandlerUseDB ) {
 366                         $fields[] = 'page_content_model';
 367                 }
 368
 369                 if ( $wgPageLanguageUseDB ) {
 370                         $fields[] = 'page_lang';
 371                 }
 372
 373                 return $fields;
 374         }
 375
 376         /**
 377          * Create a new Title from an article ID
 378          *
 379          * @param int $id The page_id corresponding to the Title to create
 380          * @param int $flags Use Title::GAID_FOR_UPDATE to use master
 381          * @return Title|null The new object, or null on an error
 382          */
 383         public static function newFromID( $id, $flags = 0 ) {
 384                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
 385                 $row = $db->selectRow(
 386                         'page',
 387                         self::getSelectFields(),
 388                         [ 'page_id' => $id ],
 389                         __METHOD__
 390                 );
 391                 if ( $row !== false ) {
 392                         $title = Title::newFromRow( $row );
 393                 } else {
 394                         $title = null;
 395                 }
 396                 return $title;
 397         }
 398
 399         /**
 400          * Make an array of titles from an array of IDs
 401          *
 402          * @param int[] $ids Array of IDs
 403          * @return Title[] Array of Titles
 404          */
 405         public static function newFromIDs( $ids ) {
 406                 if ( !count( $ids ) ) {
 407                         return [];
 408                 }
 409                 $dbr = wfGetDB( DB_SLAVE );
 410
 411                 $res = $dbr->select(
 412                         'page',
 413                         self::getSelectFields(),
 414                         [ 'page_id' => $ids ],
 415                         __METHOD__
 416                 );
 417
 418                 $titles = [];
 419                 foreach ( $res as $row ) {
 420                         $titles[] = Title::newFromRow( $row );
 421                 }
 422                 return $titles;
 423         }
 424
 425         /**
 426          * Make a Title object from a DB row
 427          *
 428          * @param stdClass $row Object database row (needs at least page_title,page_namespace)
 429          * @return Title Corresponding Title
 430          */
 431         public static function newFromRow( $row ) {
 432                 $t = self::makeTitle( $row->page_namespace, $row->page_title );
 433                 $t->loadFromRow( $row );
 434                 return $t;
 435         }
 436
 437         /**
 438          * Load Title object fields from a DB row.
 439          * If false is given, the title will be treated as non-existing.
 440          *
 441          * @param stdClass|bool $row Database row
 442          */
 443         public function loadFromRow( $row ) {
 444                 if ( $row ) { // page found
 445                         if ( isset( $row->page_id ) ) {
 446                                 $this->mArticleID = (int)$row->page_id;
 447                         }
 448                         if ( isset( $row->page_len ) ) {
 449                                 $this->mLength = (int)$row->page_len;
 450                         }
 451                         if ( isset( $row->page_is_redirect ) ) {
 452                                 $this->mRedirect = (bool)$row->page_is_redirect;
 453                         }
 454                         if ( isset( $row->page_latest ) ) {
 455                                 $this->mLatestID = (int)$row->page_latest;
 456                         }
 457                         if ( isset( $row->page_content_model ) ) {
 458                                 $this->mContentModel = strval( $row->page_content_model );
 459                         } else {
 460                                 $this->mContentModel = false; # initialized lazily in getContentModel()
 461                         }
 462                         if ( isset( $row->page_lang ) ) {
 463                                 $this->mDbPageLanguage = (string)$row->page_lang;
 464                         }
 465                         if ( isset( $row->page_restrictions ) ) {
 466                                 $this->mOldRestrictions = $row->page_restrictions;
 467                         }
 468                 } else { // page not found
 469                         $this->mArticleID = 0;
 470                         $this->mLength = 0;
 471                         $this->mRedirect = false;
 472                         $this->mLatestID = 0;
 473                         $this->mContentModel = false; # initialized lazily in getContentModel()
 474                 }
 475         }
 476
 477         /**
 478          * Create a new Title from a namespace index and a DB key.
 479          * It's assumed that $ns and $title are *valid*, for instance when
 480          * they came directly from the database or a special page name.
 481          * For convenience, spaces are converted to underscores so that
 482          * eg user_text fields can be used directly.
 483          *
 484          * @param int $ns The namespace of the article
 485          * @param string $title The unprefixed database key form
 486          * @param string $fragment The link fragment (after the "#")
 487          * @param string $interwiki The interwiki prefix
 488          * @return Title The new object
 489          */
 490         public static function &makeTitle( $ns, $title, $fragment = '', $interwiki = '' ) {
 491                 $t = new Title();
 492                 $t->mInterwiki = $interwiki;
 493                 $t->mFragment = $fragment;
 494                 $t->mNamespace = $ns = intval( $ns );
 495                 $t->mDbkeyform = strtr( $title, ' ', '_' );
 496                 $t->mArticleID = ( $ns >= 0 ) ? -1 : 0;
 497                 $t->mUrlform = wfUrlencode( $t->mDbkeyform );
 498                 $t->mTextform = strtr( $title, '_', ' ' );
 499                 $t->mContentModel = false; # initialized lazily in getContentModel()
 500                 return $t;
 501         }
 502
 503         /**
 504          * Create a new Title from a namespace index and a DB key.
 505          * The parameters will be checked for validity, which is a bit slower
 506          * than makeTitle() but safer for user-provided data.
 507          *
 508          * @param int $ns The namespace of the article
 509          * @param string $title Database key form
 510          * @param string $fragment The link fragment (after the "#")
 511          * @param string $interwiki Interwiki prefix
 512          * @return Title|null The new object, or null on an error
 513          */
 514         public static function makeTitleSafe( $ns, $title, $fragment = '', $interwiki = '' ) {
 515                 if ( !MWNamespace::exists( $ns ) ) {
 516                         return null;
 517                 }
 518
 519                 $t = new Title();
 520                 $t->mDbkeyform = Title::makeName( $ns, $title, $fragment, $interwiki, true );
 521
 522                 try {
 523                         $t->secureAndSplit();
 524                         return $t;
 525                 } catch ( MalformedTitleException $ex ) {
 526                         return null;
 527                 }
 528         }
 529
 530         /**
 531          * Create a new Title for the Main Page
 532          *
 533          * @return Title The new object
 534          */
 535         public static function newMainPage() {
 536                 $title = Title::newFromText( wfMessage( 'mainpage' )->inContentLanguage()->text() );
 537                 // Don't give fatal errors if the message is broken
 538                 if ( !$title ) {
 539                         $title = Title::newFromText( 'Main Page' );
 540                 }
 541                 return $title;
 542         }
 543
 544         /**
 545          * Get the prefixed DB key associated with an ID
 546          *
 547          * @param int $id The page_id of the article
 548          * @return Title|null An object representing the article, or null if no such article was found
 549          */
 550         public static function nameOf( $id ) {
 551                 $dbr = wfGetDB( DB_SLAVE );
 552
 553                 $s = $dbr->selectRow(
 554                         'page',
 555                         [ 'page_namespace', 'page_title' ],
 556                         [ 'page_id' => $id ],
 557                         __METHOD__
 558                 );
 559                 if ( $s === false ) {
 560                         return null;
 561                 }
 562
 563                 $n = self::makeName( $s->page_namespace, $s->page_title );
 564                 return $n;
 565         }
 566
 567         /**
 568          * Get a regex character class describing the legal characters in a link
 569          *
 570          * @return string The list of characters, not delimited
 571          */
 572         public static function legalChars() {
 573                 global $wgLegalTitleChars;
 574                 return $wgLegalTitleChars;
 575         }
 576
 577         /**
 578          * Returns a simple regex that will match on characters and sequences invalid in titles.
 579          * Note that this doesn't pick up many things that could be wrong with titles, but that
 580          * replacing this regex with something valid will make many titles valid.
 581          *
 582          * @deprecated since 1.25, use MediaWikiTitleCodec::getTitleInvalidRegex() instead
 583          *
 584          * @return string Regex string
 585          */
 586         static function getTitleInvalidRegex() {
 587                 wfDeprecated( __METHOD__, '1.25' );
 588                 return MediaWikiTitleCodec::getTitleInvalidRegex();
 589         }
 590
 591         /**
 592          * Utility method for converting a character sequence from bytes to Unicode.
 593          *
 594          * Primary usecase being converting $wgLegalTitleChars to a sequence usable in
 595          * javascript, as PHP uses UTF-8 bytes where javascript uses Unicode code units.
 596          *
 597          * @param string $byteClass
 598          * @return string
 599          */
 600         public static function convertByteClassToUnicodeClass( $byteClass ) {
 601                 $length = strlen( $byteClass );
 602                 // Input token queue
 603                 $x0 = $x1 = $x2 = '';
 604                 // Decoded queue
 605                 $d0 = $d1 = $d2 = '';
 606                 // Decoded integer codepoints
 607                 $ord0 = $ord1 = $ord2 = 0;
 608                 // Re-encoded queue
 609                 $r0 = $r1 = $r2 = '';
 610                 // Output
 611                 $out = '';
 612                 // Flags
 613                 $allowUnicode = false;
 614                 for ( $pos = 0; $pos < $length; $pos++ ) {
 615                         // Shift the queues down
 616                         $x2 = $x1;
 617                         $x1 = $x0;
 618                         $d2 = $d1;
 619                         $d1 = $d0;
 620                         $ord2 = $ord1;
 621                         $ord1 = $ord0;
 622                         $r2 = $r1;
 623                         $r1 = $r0;
 624                         // Load the current input token and decoded values
 625                         $inChar = $byteClass[$pos];
 626                         if ( $inChar == '\\' ) {
 627                                 if ( preg_match( '/x([0-9a-fA-F]{2})/A', $byteClass, $m, 0, $pos + 1 ) ) {
 628                                         $x0 = $inChar . $m[0];
 629                                         $d0 = chr( hexdec( $m[1] ) );
 630                                         $pos += strlen( $m[0] );
 631                                 } elseif ( preg_match( '/[0-7]{3}/A', $byteClass, $m, 0, $pos + 1 ) ) {
 632                                         $x0 = $inChar . $m[0];
 633                                         $d0 = chr( octdec( $m[0] ) );
 634                                         $pos += strlen( $m[0] );
 635                                 } elseif ( $pos + 1 >= $length ) {
 636                                         $x0 = $d0 = '\\';
 637                                 } else {
 638                                         $d0 = $byteClass[$pos + 1];
 639                                         $x0 = $inChar . $d0;
 640                                         $pos += 1;
 641                                 }
 642                         } else {
 643                                 $x0 = $d0 = $inChar;
 644                         }
 645                         $ord0 = ord( $d0 );
 646                         // Load the current re-encoded value
 647                         if ( $ord0 < 32 || $ord0 == 0x7f ) {
 648                                 $r0 = sprintf( '\x%02x', $ord0 );
 649                         } elseif ( $ord0 >= 0x80 ) {
 650                                 // Allow unicode if a single high-bit character appears
 651                                 $r0 = sprintf( '\x%02x', $ord0 );
 652                                 $allowUnicode = true;
 653                         } elseif ( strpos( '-\\[]^', $d0 ) !== false ) {
 654                                 $r0 = '\\' . $d0;
 655                         } else {
 656                                 $r0 = $d0;
 657                         }
 658                         // Do the output
 659                         if ( $x0 !== '' && $x1 === '-' && $x2 !== '' ) {
 660                                 // Range
 661                                 if ( $ord2 > $ord0 ) {
 662                                         // Empty range
 663                                 } elseif ( $ord0 >= 0x80 ) {
 664                                         // Unicode range
 665                                         $allowUnicode = true;
 666                                         if ( $ord2 < 0x80 ) {
 667                                                 // Keep the non-unicode section of the range
 668                                                 $out .= "$r2-\\x7F";
 669                                         }
 670                                 } else {
 671                                         // Normal range
 672                                         $out .= "$r2-$r0";
 673                                 }
 674                                 // Reset state to the initial value
 675                                 $x0 = $x1 = $d0 = $d1 = $r0 = $r1 = '';
 676                         } elseif ( $ord2 < 0x80 ) {
 677                                 // ASCII character
 678                                 $out .= $r2;
 679                         }
 680                 }
 681                 if ( $ord1 < 0x80 ) {
 682                         $out .= $r1;
 683                 }
 684                 if ( $ord0 < 0x80 ) {
 685                         $out .= $r0;
 686                 }
 687                 if ( $allowUnicode ) {
 688                         $out .= '\u0080-\uFFFF';
 689                 }
 690                 return $out;
 691         }
 692
 693         /**
 694          * Make a prefixed DB key from a DB key and a namespace index
 695          *
 696          * @param int $ns Numerical representation of the namespace
 697          * @param string $title The DB key form the title
 698          * @param string $fragment The link fragment (after the "#")
 699          * @param string $interwiki The interwiki prefix
 700          * @param bool $canonicalNamespace If true, use the canonical name for
 701          *   $ns instead of the localized version.
 702          * @return string The prefixed form of the title
 703          */
 704         public static function makeName( $ns, $title, $fragment = '', $interwiki = '',
 705                 $canonicalNamespace = false
 706         ) {
 707                 global $wgContLang;
 708
 709                 if ( $canonicalNamespace ) {
 710                         $namespace = MWNamespace::getCanonicalName( $ns );
 711                 } else {
 712                         $namespace = $wgContLang->getNsText( $ns );
 713                 }
 714                 $name = $namespace == '' ? $title : "$namespace:$title";
 715                 if ( strval( $interwiki ) != '' ) {
 716                         $name = "$interwiki:$name";
 717                 }
 718                 if ( strval( $fragment ) != '' ) {
 719                         $name .= '#' . $fragment;
 720                 }
 721                 return $name;
 722         }
 723
 724         /**
 725          * Escape a text fragment, say from a link, for a URL
 726          *
 727          * @param string $fragment Containing a URL or link fragment (after the "#")
 728          * @return string Escaped string
 729          */
 730         static function escapeFragmentForURL( $fragment ) {
 731                 # Note that we don't urlencode the fragment.  urlencoded Unicode
 732                 # fragments appear not to work in IE (at least up to 7) or in at least
 733                 # one version of Opera 9.x.  The W3C validator, for one, doesn't seem
 734                 # to care if they aren't encoded.
 735                 return Sanitizer::escapeId( $fragment, 'noninitial' );
 736         }
 737
 738         /**
 739          * Callback for usort() to do title sorts by (namespace, title)
 740          *
 741          * @param Title $a
 742          * @param Title $b
 743          *
 744          * @return int Result of string comparison, or namespace comparison
 745          */
 746         public static function compare( $a, $b ) {
 747                 if ( $a->getNamespace() == $b->getNamespace() ) {
 748                         return strcmp( $a->getText(), $b->getText() );
 749                 } else {
 750                         return $a->getNamespace() - $b->getNamespace();
 751                 }
 752         }
 753
 754         /**
 755          * Determine whether the object refers to a page within
 756          * this project (either this wiki or a wiki with a local
 757          * interwiki, see https://www.mediawiki.org/wiki/Manual:Interwiki_table#iw_local )
 758          *
 759          * @return bool True if this is an in-project interwiki link or a wikilink, false otherwise
 760          */
 761         public function isLocal() {
 762                 if ( $this->isExternal() ) {
 763                         $iw = Interwiki::fetch( $this->mInterwiki );
 764                         if ( $iw ) {
 765                                 return $iw->isLocal();
 766                         }
 767                 }
 768                 return true;
 769         }
 770
 771         /**
 772          * Is this Title interwiki?
 773          *
 774          * @return bool
 775          */
 776         public function isExternal() {
 777                 return $this->mInterwiki !== '';
 778         }
 779
 780         /**
 781          * Get the interwiki prefix
 782          *
 783          * Use Title::isExternal to check if a interwiki is set
 784          *
 785          * @return string Interwiki prefix
 786          */
 787         public function getInterwiki() {
 788                 return $this->mInterwiki;
 789         }
 790
 791         /**
 792          * Was this a local interwiki link?
 793          *
 794          * @return bool
 795          */
 796         public function wasLocalInterwiki() {
 797                 return $this->mLocalInterwiki;
 798         }
 799
 800         /**
 801          * Determine whether the object refers to a page within
 802          * this project and is transcludable.
 803          *
 804          * @return bool True if this is transcludable
 805          */
 806         public function isTrans() {
 807                 if ( !$this->isExternal() ) {
 808                         return false;
 809                 }
 810
 811                 return Interwiki::fetch( $this->mInterwiki )->isTranscludable();
 812         }
 813
 814         /**
 815          * Returns the DB name of the distant wiki which owns the object.
 816          *
 817          * @return string The DB name
 818          */
 819         public function getTransWikiID() {
 820                 if ( !$this->isExternal() ) {
 821                         return false;
 822                 }
 823
 824                 return Interwiki::fetch( $this->mInterwiki )->getWikiID();
 825         }
 826
 827         /**
 828          * Get a TitleValue object representing this Title.
 829          *
 830          * @note Not all valid Titles have a corresponding valid TitleValue
 831          * (e.g. TitleValues cannot represent page-local links that have a
 832          * fragment but no title text).
 833          *
 834          * @return TitleValue|null
 835          */
 836         public function getTitleValue() {
 837                 if ( $this->mTitleValue === null ) {
 838                         try {
 839                                 $this->mTitleValue = new TitleValue(
 840                                         $this->getNamespace(),
 841                                         $this->getDBkey(),
 842                                         $this->getFragment(),
 843                                         $this->getInterwiki()
 844                                 );
 845                         } catch ( InvalidArgumentException $ex ) {
 846                                 wfDebug( __METHOD__ . ': Can\'t create a TitleValue for [[' .
 847                                         $this->getPrefixedText() . ']]: ' . $ex->getMessage() . "\n" );
 848                         }
 849                 }
 850
 851                 return $this->mTitleValue;
 852         }
 853
 854         /**
 855          * Get the text form (spaces not underscores) of the main part
 856          *
 857          * @return string Main part of the title
 858          */
 859         public function getText() {
 860                 return $this->mTextform;
 861         }
 862
 863         /**
 864          * Get the URL-encoded form of the main part
 865          *
 866          * @return string Main part of the title, URL-encoded
 867          */
 868         public function getPartialURL() {
 869                 return $this->mUrlform;
 870         }
 871
 872         /**
 873          * Get the main part with underscores
 874          *
 875          * @return string Main part of the title, with underscores
 876          */
 877         public function getDBkey() {
 878                 return $this->mDbkeyform;
 879         }
 880
 881         /**
 882          * Get the DB key with the initial letter case as specified by the user
 883          *
 884          * @return string DB key
 885          */
 886         function getUserCaseDBKey() {
 887                 if ( !is_null( $this->mUserCaseDBKey ) ) {
 888                         return $this->mUserCaseDBKey;
 889                 } else {
 890                         // If created via makeTitle(), $this->mUserCaseDBKey is not set.
 891                         return $this->mDbkeyform;
 892                 }
 893         }
 894
 895         /**
 896          * Get the namespace index, i.e. one of the NS_xxxx constants.
 897          *
 898          * @return int Namespace index
 899          */
 900         public function getNamespace() {
 901                 return $this->mNamespace;
 902         }
 903
 904         /**
 905          * Get the page's content model id, see the CONTENT_MODEL_XXX constants.
 906          *
 907          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
 908          * @return string Content model id
 909          */
 910         public function getContentModel( $flags = 0 ) {
 911                 if ( !$this->mContentModel && $this->getArticleID( $flags ) ) {
 912                         $linkCache = LinkCache::singleton();
 913                         $linkCache->addLinkObj( $this ); # in case we already had an article ID
 914                         $this->mContentModel = $linkCache->getGoodLinkFieldObj( $this, 'model' );
 915                 }
 916
 917                 if ( !$this->mContentModel ) {
 918                         $this->mContentModel = ContentHandler::getDefaultModelFor( $this );
 919                 }
 920
 921                 return $this->mContentModel;
 922         }
 923
 924         /**
 925          * Convenience method for checking a title's content model name
 926          *
 927          * @param string $id The content model ID (use the CONTENT_MODEL_XXX constants).
 928          * @return bool True if $this->getContentModel() == $id
 929          */
 930         public function hasContentModel( $id ) {
 931                 return $this->getContentModel() == $id;
 932         }
 933
 934         /**
 935          * Get the namespace text
 936          *
 937          * @return string Namespace text
 938          */
 939         public function getNsText() {
 940                 if ( $this->isExternal() ) {
 941                         // This probably shouldn't even happen,
 942                         // but for interwiki transclusion it sometimes does.
 943                         // Use the canonical namespaces if possible to try to
 944                         // resolve a foreign namespace.
 945                         if ( MWNamespace::exists( $this->mNamespace ) ) {
 946                                 return MWNamespace::getCanonicalName( $this->mNamespace );
 947                         }
 948                 }
 949
 950                 try {
 951                         $formatter = self::getTitleFormatter();
 952                         return $formatter->getNamespaceName( $this->mNamespace, $this->mDbkeyform );
 953                 } catch ( InvalidArgumentException $ex ) {
 954                         wfDebug( __METHOD__ . ': ' . $ex->getMessage() . "\n" );
 955                         return false;
 956                 }
 957         }
 958
 959         /**
 960          * Get the namespace text of the subject (rather than talk) page
 961          *
 962          * @return string Namespace text
 963          */
 964         public function getSubjectNsText() {
 965                 global $wgContLang;
 966                 return $wgContLang->getNsText( MWNamespace::getSubject( $this->mNamespace ) );
 967         }
 968
 969         /**
 970          * Get the namespace text of the talk page
 971          *
 972          * @return string Namespace text
 973          */
 974         public function getTalkNsText() {
 975                 global $wgContLang;
 976                 return $wgContLang->getNsText( MWNamespace::getTalk( $this->mNamespace ) );
 977         }
 978
 979         /**
 980          * Could this title have a corresponding talk page?
 981          *
 982          * @return bool
 983          */
 984         public function canTalk() {
 985                 return MWNamespace::canTalk( $this->mNamespace );
 986         }
 987
 988         /**
 989          * Is this in a namespace that allows actual pages?
 990          *
 991          * @return bool
 992          */
 993         public function canExist() {
 994                 return $this->mNamespace >= NS_MAIN;
 995         }
 996
 997         /**
 998          * Can this title be added to a user's watchlist?
 999          *
1000          * @return bool
1001          */
1002         public function isWatchable() {
1003                 return !$this->isExternal() && MWNamespace::isWatchable( $this->getNamespace() );
1004         }
1005
1006         /**
1007          * Returns true if this is a special page.
1008          *
1009          * @return bool
1010          */
1011         public function isSpecialPage() {
1012                 return $this->getNamespace() == NS_SPECIAL;
1013         }
1014
1015         /**
1016          * Returns true if this title resolves to the named special page
1017          *
1018          * @param string $name The special page name
1019          * @return bool
1020          */
1021         public function isSpecial( $name ) {
1022                 if ( $this->isSpecialPage() ) {
1023                         list( $thisName, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $this->getDBkey() );
1024                         if ( $name == $thisName ) {
1025                                 return true;
1026                         }
1027                 }
1028                 return false;
1029         }
1030
1031         /**
1032          * If the Title refers to a special page alias which is not the local default, resolve
1033          * the alias, and localise the name as necessary.  Otherwise, return $this
1034          *
1035          * @return Title
1036          */
1037         public function fixSpecialName() {
1038                 if ( $this->isSpecialPage() ) {
1039                         list( $canonicalName, $par ) = SpecialPageFactory::resolveAlias( $this->mDbkeyform );
1040                         if ( $canonicalName ) {
1041                                 $localName = SpecialPageFactory::getLocalNameFor( $canonicalName, $par );
1042                                 if ( $localName != $this->mDbkeyform ) {
1043                                         return Title::makeTitle( NS_SPECIAL, $localName );
1044                                 }
1045                         }
1046                 }
1047                 return $this;
1048         }
1049
1050         /**
1051          * Returns true if the title is inside the specified namespace.
1052          *
1053          * Please make use of this instead of comparing to getNamespace()
1054          * This function is much more resistant to changes we may make
1055          * to namespaces than code that makes direct comparisons.
1056          * @param int $ns The namespace
1057          * @return bool
1058          * @since 1.19
1059          */
1060         public function inNamespace( $ns ) {
1061                 return MWNamespace::equals( $this->getNamespace(), $ns );
1062         }
1063
1064         /**
1065          * Returns true if the title is inside one of the specified namespaces.
1066          *
1067          * @param int $namespaces,... The namespaces to check for
1068          * @return bool
1069          * @since 1.19
1070          */
1071         public function inNamespaces( /* ... */ ) {
1072                 $namespaces = func_get_args();
1073                 if ( count( $namespaces ) > 0 && is_array( $namespaces[0] ) ) {
1074                         $namespaces = $namespaces[0];
1075                 }
1076
1077                 foreach ( $namespaces as $ns ) {
1078                         if ( $this->inNamespace( $ns ) ) {
1079                                 return true;
1080                         }
1081                 }
1082
1083                 return false;
1084         }
1085
1086         /**
1087          * Returns true if the title has the same subject namespace as the
1088          * namespace specified.
1089          * For example this method will take NS_USER and return true if namespace
1090          * is either NS_USER or NS_USER_TALK since both of them have NS_USER
1091          * as their subject namespace.
1092          *
1093          * This is MUCH simpler than individually testing for equivalence
1094          * against both NS_USER and NS_USER_TALK, and is also forward compatible.
1095          * @since 1.19
1096          * @param int $ns
1097          * @return bool
1098          */
1099         public function hasSubjectNamespace( $ns ) {
1100                 return MWNamespace::subjectEquals( $this->getNamespace(), $ns );
1101         }
1102
1103         /**
1104          * Is this Title in a namespace which contains content?
1105          * In other words, is this a content page, for the purposes of calculating
1106          * statistics, etc?
1107          *
1108          * @return bool
1109          */
1110         public function isContentPage() {
1111                 return MWNamespace::isContent( $this->getNamespace() );
1112         }
1113
1114         /**
1115          * Would anybody with sufficient privileges be able to move this page?
1116          * Some pages just aren't movable.
1117          *
1118          * @return bool
1119          */
1120         public function isMovable() {
1121                 if ( !MWNamespace::isMovable( $this->getNamespace() ) || $this->isExternal() ) {
1122                         // Interwiki title or immovable namespace. Hooks don't get to override here
1123                         return false;
1124                 }
1125
1126                 $result = true;
1127                 Hooks::run( 'TitleIsMovable', [ $this, &$result ] );
1128                 return $result;
1129         }
1130
1131         /**
1132          * Is this the mainpage?
1133          * @note Title::newFromText seems to be sufficiently optimized by the title
1134          * cache that we don't need to over-optimize by doing direct comparisons and
1135          * accidentally creating new bugs where $title->equals( Title::newFromText() )
1136          * ends up reporting something differently than $title->isMainPage();
1137          *
1138          * @since 1.18
1139          * @return bool
1140          */
1141         public function isMainPage() {
1142                 return $this->equals( Title::newMainPage() );
1143         }
1144
1145         /**
1146          * Is this a subpage?
1147          *
1148          * @return bool
1149          */
1150         public function isSubpage() {
1151                 return MWNamespace::hasSubpages( $this->mNamespace )
1152                         ? strpos( $this->getText(), '/' ) !== false
1153                         : false;
1154         }
1155
1156         /**
1157          * Is this a conversion table for the LanguageConverter?
1158          *
1159          * @return bool
1160          */
1161         public function isConversionTable() {
1162                 // @todo ConversionTable should become a separate content model.
1163
1164                 return $this->getNamespace() == NS_MEDIAWIKI &&
1165                         strpos( $this->getText(), 'Conversiontable/' ) === 0;
1166         }
1167
1168         /**
1169          * Does that page contain wikitext, or it is JS, CSS or whatever?
1170          *
1171          * @return bool
1172          */
1173         public function isWikitextPage() {
1174                 return $this->hasContentModel( CONTENT_MODEL_WIKITEXT );
1175         }
1176
1177         /**
1178          * Could this page contain custom CSS or JavaScript for the global UI.
1179          * This is generally true for pages in the MediaWiki namespace having CONTENT_MODEL_CSS
1180          * or CONTENT_MODEL_JAVASCRIPT.
1181          *
1182          * This method does *not* return true for per-user JS/CSS. Use isCssJsSubpage()
1183          * for that!
1184          *
1185          * Note that this method should not return true for pages that contain and
1186          * show "inactive" CSS or JS.
1187          *
1188          * @return bool
1189          * @todo FIXME: Rename to isSiteConfigPage() and remove deprecated hook
1190          */
1191         public function isCssOrJsPage() {
1192                 $isCssOrJsPage = NS_MEDIAWIKI == $this->mNamespace
1193                         && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1194                                 || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1195
1196                 # @note This hook is also called in ContentHandler::getDefaultModel.
1197                 #   It's called here again to make sure hook functions can force this
1198                 #   method to return true even outside the MediaWiki namespace.
1199
1200                 Hooks::run( 'TitleIsCssOrJsPage', [ $this, &$isCssOrJsPage ], '1.25' );
1201
1202                 return $isCssOrJsPage;
1203         }
1204
1205         /**
1206          * Is this a .css or .js subpage of a user page?
1207          * @return bool
1208          * @todo FIXME: Rename to isUserConfigPage()
1209          */
1210         public function isCssJsSubpage() {
1211                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1212                                 && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1213                                         || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) ) );
1214         }
1215
1216         /**
1217          * Trim down a .css or .js subpage title to get the corresponding skin name
1218          *
1219          * @return string Containing skin name from .css or .js subpage title
1220          */
1221         public function getSkinFromCssJsSubpage() {
1222                 $subpage = explode( '/', $this->mTextform );
1223                 $subpage = $subpage[count( $subpage ) - 1];
1224                 $lastdot = strrpos( $subpage, '.' );
1225                 if ( $lastdot === false ) {
1226                         return $subpage; # Never happens: only called for names ending in '.css' or '.js'
1227                 }
1228                 return substr( $subpage, 0, $lastdot );
1229         }
1230
1231         /**
1232          * Is this a .css subpage of a user page?
1233          *
1234          * @return bool
1235          */
1236         public function isCssSubpage() {
1237                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1238                         && $this->hasContentModel( CONTENT_MODEL_CSS ) );
1239         }
1240
1241         /**
1242          * Is this a .js subpage of a user page?
1243          *
1244          * @return bool
1245          */
1246         public function isJsSubpage() {
1247                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1248                         && $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1249         }
1250
1251         /**
1252          * Is this a talk page of some sort?
1253          *
1254          * @return bool
1255          */
1256         public function isTalkPage() {
1257                 return MWNamespace::isTalk( $this->getNamespace() );
1258         }
1259
1260         /**
1261          * Get a Title object associated with the talk page of this article
1262          *
1263          * @return Title The object for the talk page
1264          */
1265         public function getTalkPage() {
1266                 return Title::makeTitle( MWNamespace::getTalk( $this->getNamespace() ), $this->getDBkey() );
1267         }
1268
1269         /**
1270          * Get a title object associated with the subject page of this
1271          * talk page
1272          *
1273          * @return Title The object for the subject page
1274          */
1275         public function getSubjectPage() {
1276                 // Is this the same title?
1277                 $subjectNS = MWNamespace::getSubject( $this->getNamespace() );
1278                 if ( $this->getNamespace() == $subjectNS ) {
1279                         return $this;
1280                 }
1281                 return Title::makeTitle( $subjectNS, $this->getDBkey() );
1282         }
1283
1284         /**
1285          * Get the other title for this page, if this is a subject page
1286          * get the talk page, if it is a subject page get the talk page
1287          *
1288          * @since 1.25
1289          * @throws MWException
1290          * @return Title
1291          */
1292         public function getOtherPage() {
1293                 if ( $this->isSpecialPage() ) {
1294                         throw new MWException( 'Special pages cannot have other pages' );
1295                 }
1296                 if ( $this->isTalkPage() ) {
1297                         return $this->getSubjectPage();
1298                 } else {
1299                         return $this->getTalkPage();
1300                 }
1301         }
1302
1303         /**
1304          * Get the default namespace index, for when there is no namespace
1305          *
1306          * @return int Default namespace index
1307          */
1308         public function getDefaultNamespace() {
1309                 return $this->mDefaultNamespace;
1310         }
1311
1312         /**
1313          * Get the Title fragment (i.e.\ the bit after the #) in text form
1314          *
1315          * Use Title::hasFragment to check for a fragment
1316          *
1317          * @return string Title fragment
1318          */
1319         public function getFragment() {
1320                 return $this->mFragment;
1321         }
1322
1323         /**
1324          * Check if a Title fragment is set
1325          *
1326          * @return bool
1327          * @since 1.23
1328          */
1329         public function hasFragment() {
1330                 return $this->mFragment !== '';
1331         }
1332
1333         /**
1334          * Get the fragment in URL form, including the "#" character if there is one
1335          * @return string Fragment in URL form
1336          */
1337         public function getFragmentForURL() {
1338                 if ( !$this->hasFragment() ) {
1339                         return '';
1340                 } else {
1341                         return '#' . Title::escapeFragmentForURL( $this->getFragment() );
1342                 }
1343         }
1344
1345         /**
1346          * Set the fragment for this title. Removes the first character from the
1347          * specified fragment before setting, so it assumes you're passing it with
1348          * an initial "#".
1349          *
1350          * Deprecated for public use, use Title::makeTitle() with fragment parameter,
1351          * or Title::createFragmentTarget().
1352          * Still in active use privately.
1353          *
1354          * @private
1355          * @param string $fragment Text
1356          */
1357         public function setFragment( $fragment ) {
1358                 $this->mFragment = strtr( substr( $fragment, 1 ), '_', ' ' );
1359         }
1360
1361         /**
1362          * Creates a new Title for a different fragment of the same page.
1363          *
1364          * @since 1.27
1365          * @param string $fragment
1366          * @return Title
1367          */
1368         public function createFragmentTarget( $fragment ) {
1369                 return self::makeTitle(
1370                         $this->getNamespace(),
1371                         $this->getText(),
1372                         $fragment,
1373                         $this->getInterwiki()
1374                 );
1375
1376         }
1377
1378         /**
1379          * Prefix some arbitrary text with the namespace or interwiki prefix
1380          * of this object
1381          *
1382          * @param string $name The text
1383          * @return string The prefixed text
1384          */
1385         private function prefix( $name ) {
1386                 $p = '';
1387                 if ( $this->isExternal() ) {
1388                         $p = $this->mInterwiki . ':';
1389                 }
1390
1391                 if ( 0 != $this->mNamespace ) {
1392                         $p .= $this->getNsText() . ':';
1393                 }
1394                 return $p . $name;
1395         }
1396
1397         /**
1398          * Get the prefixed database key form
1399          *
1400          * @return string The prefixed title, with underscores and
1401          *  any interwiki and namespace prefixes
1402          */
1403         public function getPrefixedDBkey() {
1404                 $s = $this->prefix( $this->mDbkeyform );
1405                 $s = strtr( $s, ' ', '_' );
1406                 return $s;
1407         }
1408
1409         /**
1410          * Get the prefixed title with spaces.
1411          * This is the form usually used for display
1412          *
1413          * @return string The prefixed title, with spaces
1414          */
1415         public function getPrefixedText() {
1416                 if ( $this->mPrefixedText === null ) {
1417                         $s = $this->prefix( $this->mTextform );
1418                         $s = strtr( $s, '_', ' ' );
1419                         $this->mPrefixedText = $s;
1420                 }
1421                 return $this->mPrefixedText;
1422         }
1423
1424         /**
1425          * Return a string representation of this title
1426          *
1427          * @return string Representation of this title
1428          */
1429         public function __toString() {
1430                 return $this->getPrefixedText();
1431         }
1432
1433         /**
1434          * Get the prefixed title with spaces, plus any fragment
1435          * (part beginning with '#')
1436          *
1437          * @return string The prefixed title, with spaces and the fragment, including '#'
1438          */
1439         public function getFullText() {
1440                 $text = $this->getPrefixedText();
1441                 if ( $this->hasFragment() ) {
1442                         $text .= '#' . $this->getFragment();
1443                 }
1444                 return $text;
1445         }
1446
1447         /**
1448          * Get the root page name text without a namespace, i.e. the leftmost part before any slashes
1449          *
1450          * @par Example:
1451          * @code
1452          * Title::newFromText('User:Foo/Bar/Baz')->getRootText();
1453          * # returns: 'Foo'
1454          * @endcode
1455          *
1456          * @return string Root name
1457          * @since 1.20
1458          */
1459         public function getRootText() {
1460                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1461                         return $this->getText();
1462                 }
1463
1464                 return strtok( $this->getText(), '/' );
1465         }
1466
1467         /**
1468          * Get the root page name title, i.e. the leftmost part before any slashes
1469          *
1470          * @par Example:
1471          * @code
1472          * Title::newFromText('User:Foo/Bar/Baz')->getRootTitle();
1473          * # returns: Title{User:Foo}
1474          * @endcode
1475          *
1476          * @return Title Root title
1477          * @since 1.20
1478          */
1479         public function getRootTitle() {
1480                 return Title::makeTitle( $this->getNamespace(), $this->getRootText() );
1481         }
1482
1483         /**
1484          * Get the base page name without a namespace, i.e. the part before the subpage name
1485          *
1486          * @par Example:
1487          * @code
1488          * Title::newFromText('User:Foo/Bar/Baz')->getBaseText();
1489          * # returns: 'Foo/Bar'
1490          * @endcode
1491          *
1492          * @return string Base name
1493          */
1494         public function getBaseText() {
1495                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1496                         return $this->getText();
1497                 }
1498
1499                 $parts = explode( '/', $this->getText() );
1500                 # Don't discard the real title if there's no subpage involved
1501                 if ( count( $parts ) > 1 ) {
1502                         unset( $parts[count( $parts ) - 1] );
1503                 }
1504                 return implode( '/', $parts );
1505         }
1506
1507         /**
1508          * Get the base page name title, i.e. the part before the subpage name
1509          *
1510          * @par Example:
1511          * @code
1512          * Title::newFromText('User:Foo/Bar/Baz')->getBaseTitle();
1513          * # returns: Title{User:Foo/Bar}
1514          * @endcode
1515          *
1516          * @return Title Base title
1517          * @since 1.20
1518          */
1519         public function getBaseTitle() {
1520                 return Title::makeTitle( $this->getNamespace(), $this->getBaseText() );
1521         }
1522
1523         /**
1524          * Get the lowest-level subpage name, i.e. the rightmost part after any slashes
1525          *
1526          * @par Example:
1527          * @code
1528          * Title::newFromText('User:Foo/Bar/Baz')->getSubpageText();
1529          * # returns: "Baz"
1530          * @endcode
1531          *
1532          * @return string Subpage name
1533          */
1534         public function getSubpageText() {
1535                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1536                         return $this->mTextform;
1537                 }
1538                 $parts = explode( '/', $this->mTextform );
1539                 return $parts[count( $parts ) - 1];
1540         }
1541
1542         /**
1543          * Get the title for a subpage of the current page
1544          *
1545          * @par Example:
1546          * @code
1547          * Title::newFromText('User:Foo/Bar/Baz')->getSubpage("Asdf");
1548          * # returns: Title{User:Foo/Bar/Baz/Asdf}
1549          * @endcode
1550          *
1551          * @param string $text The subpage name to add to the title
1552          * @return Title Subpage title
1553          * @since 1.20
1554          */
1555         public function getSubpage( $text ) {
1556                 return Title::makeTitleSafe( $this->getNamespace(), $this->getText() . '/' . $text );
1557         }
1558
1559         /**
1560          * Get a URL-encoded form of the subpage text
1561          *
1562          * @return string URL-encoded subpage name
1563          */
1564         public function getSubpageUrlForm() {
1565                 $text = $this->getSubpageText();
1566                 $text = wfUrlencode( strtr( $text, ' ', '_' ) );
1567                 return $text;
1568         }
1569
1570         /**
1571          * Get a URL-encoded title (not an actual URL) including interwiki
1572          *
1573          * @return string The URL-encoded form
1574          */
1575         public function getPrefixedURL() {
1576                 $s = $this->prefix( $this->mDbkeyform );
1577                 $s = wfUrlencode( strtr( $s, ' ', '_' ) );
1578                 return $s;
1579         }
1580
1581         /**
1582          * Helper to fix up the get{Canonical,Full,Link,Local,Internal}URL args
1583          * get{Canonical,Full,Link,Local,Internal}URL methods accepted an optional
1584          * second argument named variant. This was deprecated in favor
1585          * of passing an array of option with a "variant" key
1586          * Once $query2 is removed for good, this helper can be dropped
1587          * and the wfArrayToCgi moved to getLocalURL();
1588          *
1589          * @since 1.19 (r105919)
1590          * @param array|string $query
1591          * @param bool $query2
1592          * @return string
1593          */
1594         private static function fixUrlQueryArgs( $query, $query2 = false ) {
1595                 if ( $query2 !== false ) {
1596                         wfDeprecated( "Title::get{Canonical,Full,Link,Local,Internal}URL " .
1597                                 "method called with a second parameter is deprecated. Add your " .
1598                                 "parameter to an array passed as the first parameter.", "1.19" );
1599                 }
1600                 if ( is_array( $query ) ) {
1601                         $query = wfArrayToCgi( $query );
1602                 }
1603                 if ( $query2 ) {
1604                         if ( is_string( $query2 ) ) {
1605                                 // $query2 is a string, we will consider this to be
1606                                 // a deprecated $variant argument and add it to the query
1607                                 $query2 = wfArrayToCgi( [ 'variant' => $query2 ] );
1608                         } else {
1609                                 $query2 = wfArrayToCgi( $query2 );
1610                         }
1611                         // If we have $query content add a & to it first
1612                         if ( $query ) {
1613                                 $query .= '&';
1614                         }
1615                         // Now append the queries together
1616                         $query .= $query2;
1617                 }
1618                 return $query;
1619         }
1620
1621         /**
1622          * Get a real URL referring to this title, with interwiki link and
1623          * fragment
1624          *
1625          * @see self::getLocalURL for the arguments.
1626          * @see wfExpandUrl
1627          * @param array|string $query
1628          * @param bool $query2
1629          * @param string $proto Protocol type to use in URL
1630          * @return string The URL
1631          */
1632         public function getFullURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1633                 $query = self::fixUrlQueryArgs( $query, $query2 );
1634
1635                 # Hand off all the decisions on urls to getLocalURL
1636                 $url = $this->getLocalURL( $query );
1637
1638                 # Expand the url to make it a full url. Note that getLocalURL has the
1639                 # potential to output full urls for a variety of reasons, so we use
1640                 # wfExpandUrl instead of simply prepending $wgServer
1641                 $url = wfExpandUrl( $url, $proto );
1642
1643                 # Finally, add the fragment.
1644                 $url .= $this->getFragmentForURL();
1645
1646                 Hooks::run( 'GetFullURL', [ &$this, &$url, $query ] );
1647                 return $url;
1648         }
1649
1650         /**
1651          * Get a URL with no fragment or server name (relative URL) from a Title object.
1652          * If this page is generated with action=render, however,
1653          * $wgServer is prepended to make an absolute URL.
1654          *
1655          * @see self::getFullURL to always get an absolute URL.
1656          * @see self::getLinkURL to always get a URL that's the simplest URL that will be
1657          *  valid to link, locally, to the current Title.
1658          * @see self::newFromText to produce a Title object.
1659          *
1660          * @param string|array $query An optional query string,
1661          *   not used for interwiki links. Can be specified as an associative array as well,
1662          *   e.g., array( 'action' => 'edit' ) (keys and values will be URL-escaped).
1663          *   Some query patterns will trigger various shorturl path replacements.
1664          * @param array $query2 An optional secondary query array. This one MUST
1665          *   be an array. If a string is passed it will be interpreted as a deprecated
1666          *   variant argument and urlencoded into a variant= argument.
1667          *   This second query argument will be added to the $query
1668          *   The second parameter is deprecated since 1.19. Pass it as a key,value
1669          *   pair in the first parameter array instead.
1670          *
1671          * @return string String of the URL.
1672          */
1673         public function getLocalURL( $query = '', $query2 = false ) {
1674                 global $wgArticlePath, $wgScript, $wgServer, $wgRequest;
1675
1676                 $query = self::fixUrlQueryArgs( $query, $query2 );
1677
1678                 $interwiki = Interwiki::fetch( $this->mInterwiki );
1679                 if ( $interwiki ) {
1680                         $namespace = $this->getNsText();
1681                         if ( $namespace != '' ) {
1682                                 # Can this actually happen? Interwikis shouldn't be parsed.
1683                                 # Yes! It can in interwiki transclusion. But... it probably shouldn't.
1684                                 $namespace .= ':';
1685                         }
1686                         $url = $interwiki->getURL( $namespace . $this->getDBkey() );
1687                         $url = wfAppendQuery( $url, $query );
1688                 } else {
1689                         $dbkey = wfUrlencode( $this->getPrefixedDBkey() );
1690                         if ( $query == '' ) {
1691                                 $url = str_replace( '$1', $dbkey, $wgArticlePath );
1692                                 Hooks::run( 'GetLocalURL::Article', [ &$this, &$url ] );
1693                         } else {
1694                                 global $wgVariantArticlePath, $wgActionPaths, $wgContLang;
1695                                 $url = false;
1696                                 $matches = [];
1697
1698                                 if ( !empty( $wgActionPaths )
1699                                         && preg_match( '/^(.*&|)action=([^&]*)(&(.*)|)$/', $query, $matches )
1700                                 ) {
1701                                         $action = urldecode( $matches[2] );
1702                                         if ( isset( $wgActionPaths[$action] ) ) {
1703                                                 $query = $matches[1];
1704                                                 if ( isset( $matches[4] ) ) {
1705                                                         $query .= $matches[4];
1706                                                 }
1707                                                 $url = str_replace( '$1', $dbkey, $wgActionPaths[$action] );
1708                                                 if ( $query != '' ) {
1709                                                         $url = wfAppendQuery( $url, $query );
1710                                                 }
1711                                         }
1712                                 }
1713
1714                                 if ( $url === false
1715                                         && $wgVariantArticlePath
1716                                         && $wgContLang->getCode() === $this->getPageLanguage()->getCode()
1717                                         && $this->getPageLanguage()->hasVariants()
1718                                         && preg_match( '/^variant=([^&]*)$/', $query, $matches )
1719                                 ) {
1720                                         $variant = urldecode( $matches[1] );
1721                                         if ( $this->getPageLanguage()->hasVariant( $variant ) ) {
1722                                                 // Only do the variant replacement if the given variant is a valid
1723                                                 // variant for the page's language.
1724                                                 $url = str_replace( '$2', urlencode( $variant ), $wgVariantArticlePath );
1725                                                 $url = str_replace( '$1', $dbkey, $url );
1726                                         }
1727                                 }
1728
1729                                 if ( $url === false ) {
1730                                         if ( $query == '-' ) {
1731                                                 $query = '';
1732                                         }
1733                                         $url = "{$wgScript}?title={$dbkey}&{$query}";
1734                                 }
1735                         }
1736
1737                         Hooks::run( 'GetLocalURL::Internal', [ &$this, &$url, $query ] );
1738
1739                         // @todo FIXME: This causes breakage in various places when we
1740                         // actually expected a local URL and end up with dupe prefixes.
1741                         if ( $wgRequest->getVal( 'action' ) == 'render' ) {
1742                                 $url = $wgServer . $url;
1743                         }
1744                 }
1745                 Hooks::run( 'GetLocalURL', [ &$this, &$url, $query ] );
1746                 return $url;
1747         }
1748
1749         /**
1750          * Get a URL that's the simplest URL that will be valid to link, locally,
1751          * to the current Title.  It includes the fragment, but does not include
1752          * the server unless action=render is used (or the link is external).  If
1753          * there's a fragment but the prefixed text is empty, we just return a link
1754          * to the fragment.
1755          *
1756          * The result obviously should not be URL-escaped, but does need to be
1757          * HTML-escaped if it's being output in HTML.
1758          *
1759          * @param array $query
1760          * @param bool $query2
1761          * @param string $proto Protocol to use; setting this will cause a full URL to be used
1762          * @see self::getLocalURL for the arguments.
1763          * @return string The URL
1764          */
1765         public function getLinkURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1766                 if ( $this->isExternal() || $proto !== PROTO_RELATIVE ) {
1767                         $ret = $this->getFullURL( $query, $query2, $proto );
1768                 } elseif ( $this->getPrefixedText() === '' && $this->hasFragment() ) {
1769                         $ret = $this->getFragmentForURL();
1770                 } else {
1771                         $ret = $this->getLocalURL( $query, $query2 ) . $this->getFragmentForURL();
1772                 }
1773                 return $ret;
1774         }
1775
1776         /**
1777          * Get the URL form for an internal link.
1778          * - Used in various CDN-related code, in case we have a different
1779          * internal hostname for the server from the exposed one.
1780          *
1781          * This uses $wgInternalServer to qualify the path, or $wgServer
1782          * if $wgInternalServer is not set. If the server variable used is
1783          * protocol-relative, the URL will be expanded to http://
1784          *
1785          * @see self::getLocalURL for the arguments.
1786          * @return string The URL
1787          */
1788         public function getInternalURL( $query = '', $query2 = false ) {
1789                 global $wgInternalServer, $wgServer;
1790                 $query = self::fixUrlQueryArgs( $query, $query2 );
1791                 $server = $wgInternalServer !== false ? $wgInternalServer : $wgServer;
1792                 $url = wfExpandUrl( $server . $this->getLocalURL( $query ), PROTO_HTTP );
1793                 Hooks::run( 'GetInternalURL', [ &$this, &$url, $query ] );
1794                 return $url;
1795         }
1796
1797         /**
1798          * Get the URL for a canonical link, for use in things like IRC and
1799          * e-mail notifications. Uses $wgCanonicalServer and the
1800          * GetCanonicalURL hook.
1801          *
1802          * NOTE: Unlike getInternalURL(), the canonical URL includes the fragment
1803          *
1804          * @see self::getLocalURL for the arguments.
1805          * @return string The URL
1806          * @since 1.18
1807          */
1808         public function getCanonicalURL( $query = '', $query2 = false ) {
1809                 $query = self::fixUrlQueryArgs( $query, $query2 );
1810                 $url = wfExpandUrl( $this->getLocalURL( $query ) . $this->getFragmentForURL(), PROTO_CANONICAL );
1811                 Hooks::run( 'GetCanonicalURL', [ &$this, &$url, $query ] );
1812                 return $url;
1813         }
1814
1815         /**
1816          * Get the edit URL for this Title
1817          *
1818          * @return string The URL, or a null string if this is an interwiki link
1819          */
1820         public function getEditURL() {
1821                 if ( $this->isExternal() ) {
1822                         return '';
1823                 }
1824                 $s = $this->getLocalURL( 'action=edit' );
1825
1826                 return $s;
1827         }
1828
1829         /**
1830          * Can $user perform $action on this page?
1831          * This skips potentially expensive cascading permission checks
1832          * as well as avoids expensive error formatting
1833          *
1834          * Suitable for use for nonessential UI controls in common cases, but
1835          * _not_ for functional access control.
1836          *
1837          * May provide false positives, but should never provide a false negative.
1838          *
1839          * @param string $action Action that permission needs to be checked for
1840          * @param User $user User to check (since 1.19); $wgUser will be used if not provided.
1841          * @return bool
1842          */
1843         public function quickUserCan( $action, $user = null ) {
1844                 return $this->userCan( $action, $user, false );
1845         }
1846
1847         /**
1848          * Can $user perform $action on this page?
1849          *
1850          * @param string $action Action that permission needs to be checked for
1851          * @param User $user User to check (since 1.19); $wgUser will be used if not
1852          *   provided.
1853          * @param string $rigor Same format as Title::getUserPermissionsErrors()
1854          * @return bool
1855          */
1856         public function userCan( $action, $user = null, $rigor = 'secure' ) {
1857                 if ( !$user instanceof User ) {
1858                         global $wgUser;
1859                         $user = $wgUser;
1860                 }
1861
1862                 return !count( $this->getUserPermissionsErrorsInternal( $action, $user, $rigor, true ) );
1863         }
1864
1865         /**
1866          * Can $user perform $action on this page?
1867          *
1868          * @todo FIXME: This *does not* check throttles (User::pingLimiter()).
1869          *
1870          * @param string $action Action that permission needs to be checked for
1871          * @param User $user User to check
1872          * @param string $rigor One of (quick,full,secure)
1873          *   - quick  : does cheap permission checks from slaves (usable for GUI creation)
1874          *   - full   : does cheap and expensive checks possibly from a slave
1875          *   - secure : does cheap and expensive checks, using the master as needed
1876          * @param array $ignoreErrors Array of Strings Set this to a list of message keys
1877          *   whose corresponding errors may be ignored.
1878          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
1879          */
1880         public function getUserPermissionsErrors(
1881                 $action, $user, $rigor = 'secure', $ignoreErrors = []
1882         ) {
1883                 $errors = $this->getUserPermissionsErrorsInternal( $action, $user, $rigor );
1884
1885                 // Remove the errors being ignored.
1886                 foreach ( $errors as $index => $error ) {
1887                         $errKey = is_array( $error ) ? $error[0] : $error;
1888
1889                         if ( in_array( $errKey, $ignoreErrors ) ) {
1890                                 unset( $errors[$index] );
1891                         }
1892                         if ( $errKey instanceof MessageSpecifier && in_array( $errKey->getKey(), $ignoreErrors ) ) {
1893                                 unset( $errors[$index] );
1894                         }
1895                 }
1896
1897                 return $errors;
1898         }
1899
1900         /**
1901          * Permissions checks that fail most often, and which are easiest to test.
1902          *
1903          * @param string $action The action to check
1904          * @param User $user User to check
1905          * @param array $errors List of current errors
1906          * @param string $rigor Same format as Title::getUserPermissionsErrors()
1907          * @param bool $short Short circuit on first error
1908          *
1909          * @return array List of errors
1910          */
1911         private function checkQuickPermissions( $action, $user, $errors, $rigor, $short ) {
1912                 if ( !Hooks::run( 'TitleQuickPermissions',
1913                         [ $this, $user, $action, &$errors, ( $rigor !== 'quick' ), $short ] )
1914                 ) {
1915                         return $errors;
1916                 }
1917
1918                 if ( $action == 'create' ) {
1919                         if (
1920                                 ( $this->isTalkPage() && !$user->isAllowed( 'createtalk' ) ) ||
1921                                 ( !$this->isTalkPage() && !$user->isAllowed( 'createpage' ) )
1922                         ) {
1923                                 $errors[] = $user->isAnon() ? [ 'nocreatetext' ] : [ 'nocreate-loggedin' ];
1924                         }
1925                 } elseif ( $action == 'move' ) {
1926                         if ( !$user->isAllowed( 'move-rootuserpages' )
1927                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
1928                                 // Show user page-specific message only if the user can move other pages
1929                                 $errors[] = [ 'cant-move-user-page' ];
1930                         }
1931
1932                         // Check if user is allowed to move files if it's a file
1933                         if ( $this->mNamespace == NS_FILE && !$user->isAllowed( 'movefile' ) ) {
1934                                 $errors[] = [ 'movenotallowedfile' ];
1935                         }
1936
1937                         // Check if user is allowed to move category pages if it's a category page
1938                         if ( $this->mNamespace == NS_CATEGORY && !$user->isAllowed( 'move-categorypages' ) ) {
1939                                 $errors[] = [ 'cant-move-category-page' ];
1940                         }
1941
1942                         if ( !$user->isAllowed( 'move' ) ) {
1943                                 // User can't move anything
1944                                 $userCanMove = User::groupHasPermission( 'user', 'move' );
1945                                 $autoconfirmedCanMove = User::groupHasPermission( 'autoconfirmed', 'move' );
1946                                 if ( $user->isAnon() && ( $userCanMove || $autoconfirmedCanMove ) ) {
1947                                         // custom message if logged-in users without any special rights can move
1948                                         $errors[] = [ 'movenologintext' ];
1949                                 } else {
1950                                         $errors[] = [ 'movenotallowed' ];
1951                                 }
1952                         }
1953                 } elseif ( $action == 'move-target' ) {
1954                         if ( !$user->isAllowed( 'move' ) ) {
1955                                 // User can't move anything
1956                                 $errors[] = [ 'movenotallowed' ];
1957                         } elseif ( !$user->isAllowed( 'move-rootuserpages' )
1958                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
1959                                 // Show user page-specific message only if the user can move other pages
1960                                 $errors[] = [ 'cant-move-to-user-page' ];
1961                         } elseif ( !$user->isAllowed( 'move-categorypages' )
1962                                         && $this->mNamespace == NS_CATEGORY ) {
1963                                 // Show category page-specific message only if the user can move other pages
1964                                 $errors[] = [ 'cant-move-to-category-page' ];
1965                         }
1966                 } elseif ( !$user->isAllowed( $action ) ) {
1967                         $errors[] = $this->missingPermissionError( $action, $short );
1968                 }
1969
1970                 return $errors;
1971         }
1972
1973         /**
1974          * Add the resulting error code to the errors array
1975          *
1976          * @param array $errors List of current errors
1977          * @param array $result Result of errors
1978          *
1979          * @return array List of errors
1980          */
1981         private function resultToError( $errors, $result ) {
1982                 if ( is_array( $result ) && count( $result ) && !is_array( $result[0] ) ) {
1983                         // A single array representing an error
1984                         $errors[] = $result;
1985                 } elseif ( is_array( $result ) && is_array( $result[0] ) ) {
1986                         // A nested array representing multiple errors
1987                         $errors = array_merge( $errors, $result );
1988                 } elseif ( $result !== '' && is_string( $result ) ) {
1989                         // A string representing a message-id
1990                         $errors[] = [ $result ];
1991                 } elseif ( $result instanceof MessageSpecifier ) {
1992                         // A message specifier representing an error
1993                         $errors[] = [ $result ];
1994                 } elseif ( $result === false ) {
1995                         // a generic "We don't want them to do that"
1996                         $errors[] = [ 'badaccess-group0' ];
1997                 }
1998                 return $errors;
1999         }
2000
2001         /**
2002          * Check various permission hooks
2003          *
2004          * @param string $action The action to check
2005          * @param User $user User to check
2006          * @param array $errors List of current errors
2007          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2008          * @param bool $short Short circuit on first error
2009          *
2010          * @return array List of errors
2011          */
2012         private function checkPermissionHooks( $action, $user, $errors, $rigor, $short ) {
2013                 // Use getUserPermissionsErrors instead
2014                 $result = '';
2015                 if ( !Hooks::run( 'userCan', [ &$this, &$user, $action, &$result ] ) ) {
2016                         return $result ? [] : [ [ 'badaccess-group0' ] ];
2017                 }
2018                 // Check getUserPermissionsErrors hook
2019                 if ( !Hooks::run( 'getUserPermissionsErrors', [ &$this, &$user, $action, &$result ] ) ) {
2020                         $errors = $this->resultToError( $errors, $result );
2021                 }
2022                 // Check getUserPermissionsErrorsExpensive hook
2023                 if (
2024                         $rigor !== 'quick'
2025                         && !( $short && count( $errors ) > 0 )
2026                         && !Hooks::run( 'getUserPermissionsErrorsExpensive', [ &$this, &$user, $action, &$result ] )
2027                 ) {
2028                         $errors = $this->resultToError( $errors, $result );
2029                 }
2030
2031                 return $errors;
2032         }
2033
2034         /**
2035          * Check permissions on special pages & namespaces
2036          *
2037          * @param string $action The action to check
2038          * @param User $user User to check
2039          * @param array $errors List of current errors
2040          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2041          * @param bool $short Short circuit on first error
2042          *
2043          * @return array List of errors
2044          */
2045         private function checkSpecialsAndNSPermissions( $action, $user, $errors, $rigor, $short ) {
2046                 # Only 'createaccount' can be performed on special pages,
2047                 # which don't actually exist in the DB.
2048                 if ( NS_SPECIAL == $this->mNamespace && $action !== 'createaccount' ) {
2049                         $errors[] = [ 'ns-specialprotected' ];
2050                 }
2051
2052                 # Check $wgNamespaceProtection for restricted namespaces
2053                 if ( $this->isNamespaceProtected( $user ) ) {
2054                         $ns = $this->mNamespace == NS_MAIN ?
2055                                 wfMessage( 'nstab-main' )->text() : $this->getNsText();
2056                         $errors[] = $this->mNamespace == NS_MEDIAWIKI ?
2057                                 [ 'protectedinterface', $action ] : [ 'namespaceprotected', $ns, $action ];
2058                 }
2059
2060                 return $errors;
2061         }
2062
2063         /**
2064          * Check CSS/JS sub-page permissions
2065          *
2066          * @param string $action The action to check
2067          * @param User $user User to check
2068          * @param array $errors List of current errors
2069          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2070          * @param bool $short Short circuit on first error
2071          *
2072          * @return array List of errors
2073          */
2074         private function checkCSSandJSPermissions( $action, $user, $errors, $rigor, $short ) {
2075                 # Protect css/js subpages of user pages
2076                 # XXX: this might be better using restrictions
2077                 # XXX: right 'editusercssjs' is deprecated, for backward compatibility only
2078                 if ( $action != 'patrol' && !$user->isAllowed( 'editusercssjs' ) ) {
2079                         if ( preg_match( '/^' . preg_quote( $user->getName(), '/' ) . '\//', $this->mTextform ) ) {
2080                                 if ( $this->isCssSubpage() && !$user->isAllowedAny( 'editmyusercss', 'editusercss' ) ) {
2081                                         $errors[] = [ 'mycustomcssprotected', $action ];
2082                                 } elseif ( $this->isJsSubpage() && !$user->isAllowedAny( 'editmyuserjs', 'edituserjs' ) ) {
2083                                         $errors[] = [ 'mycustomjsprotected', $action ];
2084                                 }
2085                         } else {
2086                                 if ( $this->isCssSubpage() && !$user->isAllowed( 'editusercss' ) ) {
2087                                         $errors[] = [ 'customcssprotected', $action ];
2088                                 } elseif ( $this->isJsSubpage() && !$user->isAllowed( 'edituserjs' ) ) {
2089                                         $errors[] = [ 'customjsprotected', $action ];
2090                                 }
2091                         }
2092                 }
2093
2094                 return $errors;
2095         }
2096
2097         /**
2098          * Check against page_restrictions table requirements on this
2099          * page. The user must possess all required rights for this
2100          * action.
2101          *
2102          * @param string $action The action to check
2103          * @param User $user User to check
2104          * @param array $errors List of current errors
2105          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2106          * @param bool $short Short circuit on first error
2107          *
2108          * @return array List of errors
2109          */
2110         private function checkPageRestrictions( $action, $user, $errors, $rigor, $short ) {
2111                 foreach ( $this->getRestrictions( $action ) as $right ) {
2112                         // Backwards compatibility, rewrite sysop -> editprotected
2113                         if ( $right == 'sysop' ) {
2114                                 $right = 'editprotected';
2115                         }
2116                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2117                         if ( $right == 'autoconfirmed' ) {
2118                                 $right = 'editsemiprotected';
2119                         }
2120                         if ( $right == '' ) {
2121                                 continue;
2122                         }
2123                         if ( !$user->isAllowed( $right ) ) {
2124                                 $errors[] = [ 'protectedpagetext', $right, $action ];
2125                         } elseif ( $this->mCascadeRestriction &&
2126                                 !$user->isAllowedAny( 'editcascadeprotected', 'protect' ) )
2127                         {
2128                                 $errors[] = [ 'protectedpagetext', 'protect', $action ];
2129                         }
2130                 }
2131
2132                 return $errors;
2133         }
2134
2135         /**
2136          * Check restrictions on cascading pages.
2137          *
2138          * @param string $action The action to check
2139          * @param User $user User to check
2140          * @param array $errors List of current errors
2141          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2142          * @param bool $short Short circuit on first error
2143          *
2144          * @return array List of errors
2145          */
2146         private function checkCascadingSourcesRestrictions( $action, $user, $errors, $rigor, $short ) {
2147                 if ( $rigor !== 'quick' && !$this->isCssJsSubpage() ) {
2148                         # We /could/ use the protection level on the source page, but it's
2149                         # fairly ugly as we have to establish a precedence hierarchy for pages
2150                         # included by multiple cascade-protected pages. So just restrict
2151                         # it to people with 'protect' permission, as they could remove the
2152                         # protection anyway.
2153                         list( $cascadingSources, $restrictions ) = $this->getCascadeProtectionSources();
2154                         # Cascading protection depends on more than this page...
2155                         # Several cascading protected pages may include this page...
2156                         # Check each cascading level
2157                         # This is only for protection restrictions, not for all actions
2158                         if ( isset( $restrictions[$action] ) ) {
2159                                 foreach ( $restrictions[$action] as $right ) {
2160                                         // Backwards compatibility, rewrite sysop -> editprotected
2161                                         if ( $right == 'sysop' ) {
2162                                                 $right = 'editprotected';
2163                                         }
2164                                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2165                                         if ( $right == 'autoconfirmed' ) {
2166                                                 $right = 'editsemiprotected';
2167                                         }
2168                                         if ( $right != '' && !$user->isAllowed( $right ) &&
2169                                                 !$user->isAllowedAny( 'editcascadeprotected', 'protect' ) )
2170                                         {
2171                                                 $pages = '';
2172                                                 foreach ( $cascadingSources as $page ) {
2173                                                         $pages .= '* [[:' . $page->getPrefixedText() . "]]\n";
2174                                                 }
2175                                                 $errors[] = [ 'cascadeprotected', count( $cascadingSources ), $pages, $action ];
2176                                         }
2177                                 }
2178                         }
2179                 }
2180
2181                 return $errors;
2182         }
2183
2184         /**
2185          * Check action permissions not already checked in checkQuickPermissions
2186          *
2187          * @param string $action The action to check
2188          * @param User $user User to check
2189          * @param array $errors List of current errors
2190          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2191          * @param bool $short Short circuit on first error
2192          *
2193          * @return array List of errors
2194          */
2195         private function checkActionPermissions( $action, $user, $errors, $rigor, $short ) {
2196                 global $wgDeleteRevisionsLimit, $wgLang;
2197
2198                 if ( $action == 'protect' ) {
2199                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit', $user, $rigor, true ) ) ) {
2200                                 // If they can't edit, they shouldn't protect.
2201                                 $errors[] = [ 'protect-cantedit' ];
2202                         }
2203                 } elseif ( $action == 'create' ) {
2204                         $title_protection = $this->getTitleProtection();
2205                         if ( $title_protection ) {
2206                                 if ( $title_protection['permission'] == ''
2207                                         || !$user->isAllowed( $title_protection['permission'] )
2208                                 ) {
2209                                         $errors[] = [
2210                                                 'titleprotected',
2211                                                 User::whoIs( $title_protection['user'] ),
2212                                                 $title_protection['reason']
2213                                         ];
2214                                 }
2215                         }
2216                 } elseif ( $action == 'move' ) {
2217                         // Check for immobile pages
2218                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2219                                 // Specific message for this case
2220                                 $errors[] = [ 'immobile-source-namespace', $this->getNsText() ];
2221                         } elseif ( !$this->isMovable() ) {
2222                                 // Less specific message for rarer cases
2223                                 $errors[] = [ 'immobile-source-page' ];
2224                         }
2225                 } elseif ( $action == 'move-target' ) {
2226                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2227                                 $errors[] = [ 'immobile-target-namespace', $this->getNsText() ];
2228                         } elseif ( !$this->isMovable() ) {
2229                                 $errors[] = [ 'immobile-target-page' ];
2230                         }
2231                 } elseif ( $action == 'delete' ) {
2232                         $tempErrors = $this->checkPageRestrictions( 'edit', $user, [], $rigor, true );
2233                         if ( !$tempErrors ) {
2234                                 $tempErrors = $this->checkCascadingSourcesRestrictions( 'edit',
2235                                         $user, $tempErrors, $rigor, true );
2236                         }
2237                         if ( $tempErrors ) {
2238                                 // If protection keeps them from editing, they shouldn't be able to delete.
2239                                 $errors[] = [ 'deleteprotected' ];
2240                         }
2241                         if ( $rigor !== 'quick' && $wgDeleteRevisionsLimit
2242                                 && !$this->userCan( 'bigdelete', $user ) && $this->isBigDeletion()
2243                         ) {
2244                                 $errors[] = [ 'delete-toobig', $wgLang->formatNum( $wgDeleteRevisionsLimit ) ];
2245                         }
2246                 }
2247                 return $errors;
2248         }
2249
2250         /**
2251          * Check that the user isn't blocked from editing.
2252          *
2253          * @param string $action The action to check
2254          * @param User $user User to check
2255          * @param array $errors List of current errors
2256          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2257          * @param bool $short Short circuit on first error
2258          *
2259          * @return array List of errors
2260          */
2261         private function checkUserBlock( $action, $user, $errors, $rigor, $short ) {
2262                 // Account creation blocks handled at userlogin.
2263                 // Unblocking handled in SpecialUnblock
2264                 if ( $rigor === 'quick' || in_array( $action, [ 'createaccount', 'unblock' ] ) ) {
2265                         return $errors;
2266                 }
2267
2268                 global $wgEmailConfirmToEdit;
2269
2270                 if ( $wgEmailConfirmToEdit && !$user->isEmailConfirmed() ) {
2271                         $errors[] = [ 'confirmedittext' ];
2272                 }
2273
2274                 $useSlave = ( $rigor !== 'secure' );
2275                 if ( ( $action == 'edit' || $action == 'create' )
2276                         && !$user->isBlockedFrom( $this, $useSlave )
2277                 ) {
2278                         // Don't block the user from editing their own talk page unless they've been
2279                         // explicitly blocked from that too.
2280                 } elseif ( $user->isBlocked() && $user->getBlock()->prevents( $action ) !== false ) {
2281                         // @todo FIXME: Pass the relevant context into this function.
2282                         $errors[] = $user->getBlock()->getPermissionsError( RequestContext::getMain() );
2283                 }
2284
2285                 return $errors;
2286         }
2287
2288         /**
2289          * Check that the user is allowed to read this page.
2290          *
2291          * @param string $action The action to check
2292          * @param User $user User to check
2293          * @param array $errors List of current errors
2294          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2295          * @param bool $short Short circuit on first error
2296          *
2297          * @return array List of errors
2298          */
2299         private function checkReadPermissions( $action, $user, $errors, $rigor, $short ) {
2300                 global $wgWhitelistRead, $wgWhitelistReadRegexp;
2301
2302                 $whitelisted = false;
2303                 if ( User::isEveryoneAllowed( 'read' ) ) {
2304                         # Shortcut for public wikis, allows skipping quite a bit of code
2305                         $whitelisted = true;
2306                 } elseif ( $user->isAllowed( 'read' ) ) {
2307                         # If the user is allowed to read pages, he is allowed to read all pages
2308                         $whitelisted = true;
2309                 } elseif ( $this->isSpecial( 'Userlogin' )
2310                         || $this->isSpecial( 'ChangePassword' )
2311                         || $this->isSpecial( 'PasswordReset' )
2312                 ) {
2313                         # Always grant access to the login page.
2314                         # Even anons need to be able to log in.
2315                         $whitelisted = true;
2316                 } elseif ( is_array( $wgWhitelistRead ) && count( $wgWhitelistRead ) ) {
2317                         # Time to check the whitelist
2318                         # Only do these checks is there's something to check against
2319                         $name = $this->getPrefixedText();
2320                         $dbName = $this->getPrefixedDBkey();
2321
2322                         // Check for explicit whitelisting with and without underscores
2323                         if ( in_array( $name, $wgWhitelistRead, true ) || in_array( $dbName, $wgWhitelistRead, true ) ) {
2324                                 $whitelisted = true;
2325                         } elseif ( $this->getNamespace() == NS_MAIN ) {
2326                                 # Old settings might have the title prefixed with
2327                                 # a colon for main-namespace pages
2328                                 if ( in_array( ':' . $name, $wgWhitelistRead ) ) {
2329                                         $whitelisted = true;
2330                                 }
2331                         } elseif ( $this->isSpecialPage() ) {
2332                                 # If it's a special page, ditch the subpage bit and check again
2333                                 $name = $this->getDBkey();
2334                                 list( $name, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $name );
2335                                 if ( $name ) {
2336                                         $pure = SpecialPage::getTitleFor( $name )->getPrefixedText();
2337                                         if ( in_array( $pure, $wgWhitelistRead, true ) ) {
2338                                                 $whitelisted = true;
2339                                         }
2340                                 }
2341                         }
2342                 }
2343
2344                 if ( !$whitelisted && is_array( $wgWhitelistReadRegexp ) && !empty( $wgWhitelistReadRegexp ) ) {
2345                         $name = $this->getPrefixedText();
2346                         // Check for regex whitelisting
2347                         foreach ( $wgWhitelistReadRegexp as $listItem ) {
2348                                 if ( preg_match( $listItem, $name ) ) {
2349                                         $whitelisted = true;
2350                                         break;
2351                                 }
2352                         }
2353                 }
2354
2355                 if ( !$whitelisted ) {
2356                         # If the title is not whitelisted, give extensions a chance to do so...
2357                         Hooks::run( 'TitleReadWhitelist', [ $this, $user, &$whitelisted ] );
2358                         if ( !$whitelisted ) {
2359                                 $errors[] = $this->missingPermissionError( $action, $short );
2360                         }
2361                 }
2362
2363                 return $errors;
2364         }
2365
2366         /**
2367          * Get a description array when the user doesn't have the right to perform
2368          * $action (i.e. when User::isAllowed() returns false)
2369          *
2370          * @param string $action The action to check
2371          * @param bool $short Short circuit on first error
2372          * @return array List of errors
2373          */
2374         private function missingPermissionError( $action, $short ) {
2375                 // We avoid expensive display logic for quickUserCan's and such
2376                 if ( $short ) {
2377                         return [ 'badaccess-group0' ];
2378                 }
2379
2380                 $groups = array_map( [ 'User', 'makeGroupLinkWiki' ],
2381                         User::getGroupsWithPermission( $action ) );
2382
2383                 if ( count( $groups ) ) {
2384                         global $wgLang;
2385                         return [
2386                                 'badaccess-groups',
2387                                 $wgLang->commaList( $groups ),
2388                                 count( $groups )
2389                         ];
2390                 } else {
2391                         return [ 'badaccess-group0' ];
2392                 }
2393         }
2394
2395         /**
2396          * Can $user perform $action on this page? This is an internal function,
2397          * with multiple levels of checks depending on performance needs; see $rigor below.
2398          * It does not check wfReadOnly().
2399          *
2400          * @param string $action Action that permission needs to be checked for
2401          * @param User $user User to check
2402          * @param string $rigor One of (quick,full,secure)
2403          *   - quick  : does cheap permission checks from slaves (usable for GUI creation)
2404          *   - full   : does cheap and expensive checks possibly from a slave
2405          *   - secure : does cheap and expensive checks, using the master as needed
2406          * @param bool $short Set this to true to stop after the first permission error.
2407          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
2408          */
2409         protected function getUserPermissionsErrorsInternal(
2410                 $action, $user, $rigor = 'secure', $short = false
2411         ) {
2412                 if ( $rigor === true ) {
2413                         $rigor = 'secure'; // b/c
2414                 } elseif ( $rigor === false ) {
2415                         $rigor = 'quick'; // b/c
2416                 } elseif ( !in_array( $rigor, [ 'quick', 'full', 'secure' ] ) ) {
2417                         throw new Exception( "Invalid rigor parameter '$rigor'." );
2418                 }
2419
2420                 # Read has special handling
2421                 if ( $action == 'read' ) {
2422                         $checks = [
2423                                 'checkPermissionHooks',
2424                                 'checkReadPermissions',
2425                         ];
2426                 # Don't call checkSpecialsAndNSPermissions or checkCSSandJSPermissions
2427                 # here as it will lead to duplicate error messages. This is okay to do
2428                 # since anywhere that checks for create will also check for edit, and
2429                 # those checks are called for edit.
2430                 } elseif ( $action == 'create' ) {
2431                         $checks = [
2432                                 'checkQuickPermissions',
2433                                 'checkPermissionHooks',
2434                                 'checkPageRestrictions',
2435                                 'checkCascadingSourcesRestrictions',
2436                                 'checkActionPermissions',
2437                                 'checkUserBlock'
2438                         ];
2439                 } else {
2440                         $checks = [
2441                                 'checkQuickPermissions',
2442                                 'checkPermissionHooks',
2443                                 'checkSpecialsAndNSPermissions',
2444                                 'checkCSSandJSPermissions',
2445                                 'checkPageRestrictions',
2446                                 'checkCascadingSourcesRestrictions',
2447                                 'checkActionPermissions',
2448                                 'checkUserBlock'
2449                         ];
2450                 }
2451
2452                 $errors = [];
2453                 while ( count( $checks ) > 0 &&
2454                                 !( $short && count( $errors ) > 0 ) ) {
2455                         $method = array_shift( $checks );
2456                         $errors = $this->$method( $action, $user, $errors, $rigor, $short );
2457                 }
2458
2459                 return $errors;
2460         }
2461
2462         /**
2463          * Get a filtered list of all restriction types supported by this wiki.
2464          * @param bool $exists True to get all restriction types that apply to
2465          * titles that do exist, False for all restriction types that apply to
2466          * titles that do not exist
2467          * @return array
2468          */
2469         public static function getFilteredRestrictionTypes( $exists = true ) {
2470                 global $wgRestrictionTypes;
2471                 $types = $wgRestrictionTypes;
2472                 if ( $exists ) {
2473                         # Remove the create restriction for existing titles
2474                         $types = array_diff( $types, [ 'create' ] );
2475                 } else {
2476                         # Only the create and upload restrictions apply to non-existing titles
2477                         $types = array_intersect( $types, [ 'create', 'upload' ] );
2478                 }
2479                 return $types;
2480         }
2481
2482         /**
2483          * Returns restriction types for the current Title
2484          *
2485          * @return array Applicable restriction types
2486          */
2487         public function getRestrictionTypes() {
2488                 if ( $this->isSpecialPage() ) {
2489                         return [];
2490                 }
2491
2492                 $types = self::getFilteredRestrictionTypes( $this->exists() );
2493
2494                 if ( $this->getNamespace() != NS_FILE ) {
2495                         # Remove the upload restriction for non-file titles
2496                         $types = array_diff( $types, [ 'upload' ] );
2497                 }
2498
2499                 Hooks::run( 'TitleGetRestrictionTypes', [ $this, &$types ] );
2500
2501                 wfDebug( __METHOD__ . ': applicable restrictions to [[' .
2502                         $this->getPrefixedText() . ']] are {' . implode( ',', $types ) . "}\n" );
2503
2504                 return $types;
2505         }
2506
2507         /**
2508          * Is this title subject to title protection?
2509          * Title protection is the one applied against creation of such title.
2510          *
2511          * @return array|bool An associative array representing any existent title
2512          *   protection, or false if there's none.
2513          */
2514         public function getTitleProtection() {
2515                 // Can't protect pages in special namespaces
2516                 if ( $this->getNamespace() < 0 ) {
2517                         return false;
2518                 }
2519
2520                 // Can't protect pages that exist.
2521                 if ( $this->exists() ) {
2522                         return false;
2523                 }
2524
2525                 if ( $this->mTitleProtection === null ) {
2526                         $dbr = wfGetDB( DB_SLAVE );
2527                         $res = $dbr->select(
2528                                 'protected_titles',
2529                                 [
2530                                         'user' => 'pt_user',
2531                                         'reason' => 'pt_reason',
2532                                         'expiry' => 'pt_expiry',
2533                                         'permission' => 'pt_create_perm'
2534                                 ],
2535                                 [ 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ],
2536                                 __METHOD__
2537                         );
2538
2539                         // fetchRow returns false if there are no rows.
2540                         $row = $dbr->fetchRow( $res );
2541                         if ( $row ) {
2542                                 if ( $row['permission'] == 'sysop' ) {
2543                                         $row['permission'] = 'editprotected'; // B/C
2544                                 }
2545                                 if ( $row['permission'] == 'autoconfirmed' ) {
2546                                         $row['permission'] = 'editsemiprotected'; // B/C
2547                                 }
2548                                 $row['expiry'] = $dbr->decodeExpiry( $row['expiry'] );
2549                         }
2550                         $this->mTitleProtection = $row;
2551                 }
2552                 return $this->mTitleProtection;
2553         }
2554
2555         /**
2556          * Remove any title protection due to page existing
2557          */
2558         public function deleteTitleProtection() {
2559                 $dbw = wfGetDB( DB_MASTER );
2560
2561                 $dbw->delete(
2562                         'protected_titles',
2563                         [ 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ],
2564                         __METHOD__
2565                 );
2566                 $this->mTitleProtection = false;
2567         }
2568
2569         /**
2570          * Is this page "semi-protected" - the *only* protection levels are listed
2571          * in $wgSemiprotectedRestrictionLevels?
2572          *
2573          * @param string $action Action to check (default: edit)
2574          * @return bool
2575          */
2576         public function isSemiProtected( $action = 'edit' ) {
2577                 global $wgSemiprotectedRestrictionLevels;
2578
2579                 $restrictions = $this->getRestrictions( $action );
2580                 $semi = $wgSemiprotectedRestrictionLevels;
2581                 if ( !$restrictions || !$semi ) {
2582                         // Not protected, or all protection is full protection
2583                         return false;
2584                 }
2585
2586                 // Remap autoconfirmed to editsemiprotected for BC
2587                 foreach ( array_keys( $semi, 'autoconfirmed' ) as $key ) {
2588                         $semi[$key] = 'editsemiprotected';
2589                 }
2590                 foreach ( array_keys( $restrictions, 'autoconfirmed' ) as $key ) {
2591                         $restrictions[$key] = 'editsemiprotected';
2592                 }
2593
2594                 return !array_diff( $restrictions, $semi );
2595         }
2596
2597         /**
2598          * Does the title correspond to a protected article?
2599          *
2600          * @param string $action The action the page is protected from,
2601          * by default checks all actions.
2602          * @return bool
2603          */
2604         public function isProtected( $action = '' ) {
2605                 global $wgRestrictionLevels;
2606
2607                 $restrictionTypes = $this->getRestrictionTypes();
2608
2609                 # Special pages have inherent protection
2610                 if ( $this->isSpecialPage() ) {
2611                         return true;
2612                 }
2613
2614                 # Check regular protection levels
2615                 foreach ( $restrictionTypes as $type ) {
2616                         if ( $action == $type || $action == '' ) {
2617                                 $r = $this->getRestrictions( $type );
2618                                 foreach ( $wgRestrictionLevels as $level ) {
2619                                         if ( in_array( $level, $r ) && $level != '' ) {
2620                                                 return true;
2621                                         }
2622                                 }
2623                         }
2624                 }
2625
2626                 return false;
2627         }
2628
2629         /**
2630          * Determines if $user is unable to edit this page because it has been protected
2631          * by $wgNamespaceProtection.
2632          *
2633          * @param User $user User object to check permissions
2634          * @return bool
2635          */
2636         public function isNamespaceProtected( User $user ) {
2637                 global $wgNamespaceProtection;
2638
2639                 if ( isset( $wgNamespaceProtection[$this->mNamespace] ) ) {
2640                         foreach ( (array)$wgNamespaceProtection[$this->mNamespace] as $right ) {
2641                                 if ( $right != '' && !$user->isAllowed( $right ) ) {
2642                                         return true;
2643                                 }
2644                         }
2645                 }
2646                 return false;
2647         }
2648
2649         /**
2650          * Cascading protection: Return true if cascading restrictions apply to this page, false if not.
2651          *
2652          * @return bool If the page is subject to cascading restrictions.
2653          */
2654         public function isCascadeProtected() {
2655                 list( $sources, /* $restrictions */ ) = $this->getCascadeProtectionSources( false );
2656                 return ( $sources > 0 );
2657         }
2658
2659         /**
2660          * Determines whether cascading protection sources have already been loaded from
2661          * the database.
2662          *
2663          * @param bool $getPages True to check if the pages are loaded, or false to check
2664          * if the status is loaded.
2665          * @return bool Whether or not the specified information has been loaded
2666          * @since 1.23
2667          */
2668         public function areCascadeProtectionSourcesLoaded( $getPages = true ) {
2669                 return $getPages ? $this->mCascadeSources !== null : $this->mHasCascadingRestrictions !== null;
2670         }
2671
2672         /**
2673          * Cascading protection: Get the source of any cascading restrictions on this page.
2674          *
2675          * @param bool $getPages Whether or not to retrieve the actual pages
2676          *        that the restrictions have come from and the actual restrictions
2677          *        themselves.
2678          * @return array Two elements: First is an array of Title objects of the
2679          *        pages from which cascading restrictions have come, false for
2680          *        none, or true if such restrictions exist but $getPages was not
2681          *        set. Second is an array like that returned by
2682          *        Title::getAllRestrictions(), or an empty array if $getPages is
2683          *        false.
2684          */
2685         public function getCascadeProtectionSources( $getPages = true ) {
2686                 $pagerestrictions = [];
2687
2688                 if ( $this->mCascadeSources !== null && $getPages ) {
2689                         return [ $this->mCascadeSources, $this->mCascadingRestrictions ];
2690                 } elseif ( $this->mHasCascadingRestrictions !== null && !$getPages ) {
2691                         return [ $this->mHasCascadingRestrictions, $pagerestrictions ];
2692                 }
2693
2694                 $dbr = wfGetDB( DB_SLAVE );
2695
2696                 if ( $this->getNamespace() == NS_FILE ) {
2697                         $tables = [ 'imagelinks', 'page_restrictions' ];
2698                         $where_clauses = [
2699                                 'il_to' => $this->getDBkey(),
2700                                 'il_from=pr_page',
2701                                 'pr_cascade' => 1
2702                         ];
2703                 } else {
2704                         $tables = [ 'templatelinks', 'page_restrictions' ];
2705                         $where_clauses = [
2706                                 'tl_namespace' => $this->getNamespace(),
2707                                 'tl_title' => $this->getDBkey(),
2708                                 'tl_from=pr_page',
2709                                 'pr_cascade' => 1
2710                         ];
2711                 }
2712
2713                 if ( $getPages ) {
2714                         $cols = [ 'pr_page', 'page_namespace', 'page_title',
2715                                 'pr_expiry', 'pr_type', 'pr_level' ];
2716                         $where_clauses[] = 'page_id=pr_page';
2717                         $tables[] = 'page';
2718                 } else {
2719                         $cols = [ 'pr_expiry' ];
2720                 }
2721
2722                 $res = $dbr->select( $tables, $cols, $where_clauses, __METHOD__ );
2723
2724                 $sources = $getPages ? [] : false;
2725                 $now = wfTimestampNow();
2726
2727                 foreach ( $res as $row ) {
2728                         $expiry = $dbr->decodeExpiry( $row->pr_expiry );
2729                         if ( $expiry > $now ) {
2730                                 if ( $getPages ) {
2731                                         $page_id = $row->pr_page;
2732                                         $page_ns = $row->page_namespace;
2733                                         $page_title = $row->page_title;
2734                                         $sources[$page_id] = Title::makeTitle( $page_ns, $page_title );
2735                                         # Add groups needed for each restriction type if its not already there
2736                                         # Make sure this restriction type still exists
2737
2738                                         if ( !isset( $pagerestrictions[$row->pr_type] ) ) {
2739                                                 $pagerestrictions[$row->pr_type] = [];
2740                                         }
2741
2742                                         if (
2743                                                 isset( $pagerestrictions[$row->pr_type] )
2744                                                 && !in_array( $row->pr_level, $pagerestrictions[$row->pr_type] )
2745                                         ) {
2746                                                 $pagerestrictions[$row->pr_type][] = $row->pr_level;
2747                                         }
2748                                 } else {
2749                                         $sources = true;
2750                                 }
2751                         }
2752                 }
2753
2754                 if ( $getPages ) {
2755                         $this->mCascadeSources = $sources;
2756                         $this->mCascadingRestrictions = $pagerestrictions;
2757                 } else {
2758                         $this->mHasCascadingRestrictions = $sources;
2759                 }
2760
2761                 return [ $sources, $pagerestrictions ];
2762         }
2763
2764         /**
2765          * Accessor for mRestrictionsLoaded
2766          *
2767          * @return bool Whether or not the page's restrictions have already been
2768          * loaded from the database
2769          * @since 1.23
2770          */
2771         public function areRestrictionsLoaded() {
2772                 return $this->mRestrictionsLoaded;
2773         }
2774
2775         /**
2776          * Accessor/initialisation for mRestrictions
2777          *
2778          * @param string $action Action that permission needs to be checked for
2779          * @return array Restriction levels needed to take the action. All levels are
2780          *     required. Note that restriction levels are normally user rights, but 'sysop'
2781          *     and 'autoconfirmed' are also allowed for backwards compatibility. These should
2782          *     be mapped to 'editprotected' and 'editsemiprotected' respectively.
2783          */
2784         public function getRestrictions( $action ) {
2785                 if ( !$this->mRestrictionsLoaded ) {
2786                         $this->loadRestrictions();
2787                 }
2788                 return isset( $this->mRestrictions[$action] )
2789                                 ? $this->mRestrictions[$action]
2790                                 : [];
2791         }
2792
2793         /**
2794          * Accessor/initialisation for mRestrictions
2795          *
2796          * @return array Keys are actions, values are arrays as returned by
2797          *     Title::getRestrictions()
2798          * @since 1.23
2799          */
2800         public function getAllRestrictions() {
2801                 if ( !$this->mRestrictionsLoaded ) {
2802                         $this->loadRestrictions();
2803                 }
2804                 return $this->mRestrictions;
2805         }
2806
2807         /**
2808          * Get the expiry time for the restriction against a given action
2809          *
2810          * @param string $action
2811          * @return string|bool 14-char timestamp, or 'infinity' if the page is protected forever
2812          *     or not protected at all, or false if the action is not recognised.
2813          */
2814         public function getRestrictionExpiry( $action ) {
2815                 if ( !$this->mRestrictionsLoaded ) {
2816                         $this->loadRestrictions();
2817                 }
2818                 return isset( $this->mRestrictionsExpiry[$action] ) ? $this->mRestrictionsExpiry[$action] : false;
2819         }
2820
2821         /**
2822          * Returns cascading restrictions for the current article
2823          *
2824          * @return bool
2825          */
2826         function areRestrictionsCascading() {
2827                 if ( !$this->mRestrictionsLoaded ) {
2828                         $this->loadRestrictions();
2829                 }
2830
2831                 return $this->mCascadeRestriction;
2832         }
2833
2834         /**
2835          * Loads a string into mRestrictions array
2836          *
2837          * @param ResultWrapper $res Resource restrictions as an SQL result.
2838          * @param string $oldFashionedRestrictions Comma-separated list of page
2839          *        restrictions from page table (pre 1.10)
2840          */
2841         private function loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions = null ) {
2842                 $rows = [];
2843
2844                 foreach ( $res as $row ) {
2845                         $rows[] = $row;
2846                 }
2847
2848                 $this->loadRestrictionsFromRows( $rows, $oldFashionedRestrictions );
2849         }
2850
2851         /**
2852          * Compiles list of active page restrictions from both page table (pre 1.10)
2853          * and page_restrictions table for this existing page.
2854          * Public for usage by LiquidThreads.
2855          *
2856          * @param array $rows Array of db result objects
2857          * @param string $oldFashionedRestrictions Comma-separated list of page
2858          *   restrictions from page table (pre 1.10)
2859          */
2860         public function loadRestrictionsFromRows( $rows, $oldFashionedRestrictions = null ) {
2861                 $dbr = wfGetDB( DB_SLAVE );
2862
2863                 $restrictionTypes = $this->getRestrictionTypes();
2864
2865                 foreach ( $restrictionTypes as $type ) {
2866                         $this->mRestrictions[$type] = [];
2867                         $this->mRestrictionsExpiry[$type] = 'infinity';
2868                 }
2869
2870                 $this->mCascadeRestriction = false;
2871
2872                 # Backwards-compatibility: also load the restrictions from the page record (old format).
2873                 if ( $oldFashionedRestrictions !== null ) {
2874                         $this->mOldRestrictions = $oldFashionedRestrictions;
2875                 }
2876
2877                 if ( $this->mOldRestrictions === false ) {
2878                         $this->mOldRestrictions = $dbr->selectField( 'page', 'page_restrictions',
2879                                 [ 'page_id' => $this->getArticleID() ], __METHOD__ );
2880                 }
2881
2882                 if ( $this->mOldRestrictions != '' ) {
2883                         foreach ( explode( ':', trim( $this->mOldRestrictions ) ) as $restrict ) {
2884                                 $temp = explode( '=', trim( $restrict ) );
2885                                 if ( count( $temp ) == 1 ) {
2886                                         // old old format should be treated as edit/move restriction
2887                                         $this->mRestrictions['edit'] = explode( ',', trim( $temp[0] ) );
2888                                         $this->mRestrictions['move'] = explode( ',', trim( $temp[0] ) );
2889                                 } else {
2890                                         $restriction = trim( $temp[1] );
2891                                         if ( $restriction != '' ) { // some old entries are empty
2892                                                 $this->mRestrictions[$temp[0]] = explode( ',', $restriction );
2893                                         }
2894                                 }
2895                         }
2896                 }
2897
2898                 if ( count( $rows ) ) {
2899                         # Current system - load second to make them override.
2900                         $now = wfTimestampNow();
2901
2902                         # Cycle through all the restrictions.
2903                         foreach ( $rows as $row ) {
2904
2905                                 // Don't take care of restrictions types that aren't allowed
2906                                 if ( !in_array( $row->pr_type, $restrictionTypes ) ) {
2907                                         continue;
2908                                 }
2909
2910                                 // This code should be refactored, now that it's being used more generally,
2911                                 // But I don't really see any harm in leaving it in Block for now -werdna
2912                                 $expiry = $dbr->decodeExpiry( $row->pr_expiry );
2913
2914                                 // Only apply the restrictions if they haven't expired!
2915                                 if ( !$expiry || $expiry > $now ) {
2916                                         $this->mRestrictionsExpiry[$row->pr_type] = $expiry;
2917                                         $this->mRestrictions[$row->pr_type] = explode( ',', trim( $row->pr_level ) );
2918
2919                                         $this->mCascadeRestriction |= $row->pr_cascade;
2920                                 }
2921                         }
2922                 }
2923
2924                 $this->mRestrictionsLoaded = true;
2925         }
2926
2927         /**
2928          * Load restrictions from the page_restrictions table
2929          *
2930          * @param string $oldFashionedRestrictions Comma-separated list of page
2931          *   restrictions from page table (pre 1.10)
2932          */
2933         public function loadRestrictions( $oldFashionedRestrictions = null ) {
2934                 if ( !$this->mRestrictionsLoaded ) {
2935                         $dbr = wfGetDB( DB_SLAVE );
2936                         if ( $this->exists() ) {
2937                                 $res = $dbr->select(
2938                                         'page_restrictions',
2939                                         [ 'pr_type', 'pr_expiry', 'pr_level', 'pr_cascade' ],
2940                                         [ 'pr_page' => $this->getArticleID() ],
2941                                         __METHOD__
2942                                 );
2943
2944                                 $this->loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions );
2945                         } else {
2946                                 $title_protection = $this->getTitleProtection();
2947
2948                                 if ( $title_protection ) {
2949                                         $now = wfTimestampNow();
2950                                         $expiry = $dbr->decodeExpiry( $title_protection['expiry'] );
2951
2952                                         if ( !$expiry || $expiry > $now ) {
2953                                                 // Apply the restrictions
2954                                                 $this->mRestrictionsExpiry['create'] = $expiry;
2955                                                 $this->mRestrictions['create'] = explode( ',', trim( $title_protection['permission'] ) );
2956                                         } else { // Get rid of the old restrictions
2957                                                 $this->mTitleProtection = false;
2958                                         }
2959                                 } else {
2960                                         $this->mRestrictionsExpiry['create'] = 'infinity';
2961                                 }
2962                                 $this->mRestrictionsLoaded = true;
2963                         }
2964                 }
2965         }
2966
2967         /**
2968          * Flush the protection cache in this object and force reload from the database.
2969          * This is used when updating protection from WikiPage::doUpdateRestrictions().
2970          */
2971         public function flushRestrictions() {
2972                 $this->mRestrictionsLoaded = false;
2973                 $this->mTitleProtection = null;
2974         }
2975
2976         /**
2977          * Purge expired restrictions from the page_restrictions table
2978          */
2979         static function purgeExpiredRestrictions() {
2980                 if ( wfReadOnly() ) {
2981                         return;
2982                 }
2983
2984                 DeferredUpdates::addUpdate( new AtomicSectionUpdate(
2985                         wfGetDB( DB_MASTER ),
2986                         __METHOD__,
2987                         function ( IDatabase $dbw, $fname ) {
2988                                 $dbw->delete(
2989                                         'page_restrictions',
2990                                         [ 'pr_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ],
2991                                         $fname
2992                                 );
2993                                 $dbw->delete(
2994                                         'protected_titles',
2995                                         [ 'pt_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ],
2996                                         $fname
2997                                 );
2998                         }
2999                 ) );
3000         }
3001
3002         /**
3003          * Does this have subpages?  (Warning, usually requires an extra DB query.)
3004          *
3005          * @return bool
3006          */
3007         public function hasSubpages() {
3008                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
3009                         # Duh
3010                         return false;
3011                 }
3012
3013                 # We dynamically add a member variable for the purpose of this method
3014                 # alone to cache the result.  There's no point in having it hanging
3015                 # around uninitialized in every Title object; therefore we only add it
3016                 # if needed and don't declare it statically.
3017                 if ( $this->mHasSubpages === null ) {
3018                         $this->mHasSubpages = false;
3019                         $subpages = $this->getSubpages( 1 );
3020                         if ( $subpages instanceof TitleArray ) {
3021                                 $this->mHasSubpages = (bool)$subpages->count();
3022                         }
3023                 }
3024
3025                 return $this->mHasSubpages;
3026         }
3027
3028         /**
3029          * Get all subpages of this page.
3030          *
3031          * @param int $limit Maximum number of subpages to fetch; -1 for no limit
3032          * @return TitleArray|array TitleArray, or empty array if this page's namespace
3033          *  doesn't allow subpages
3034          */
3035         public function getSubpages( $limit = -1 ) {
3036                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3037                         return [];
3038                 }
3039
3040                 $dbr = wfGetDB( DB_SLAVE );
3041                 $conds['page_namespace'] = $this->getNamespace();
3042                 $conds[] = 'page_title ' . $dbr->buildLike( $this->getDBkey() . '/', $dbr->anyString() );
3043                 $options = [];
3044                 if ( $limit > -1 ) {
3045                         $options['LIMIT'] = $limit;
3046                 }
3047                 $this->mSubpages = TitleArray::newFromResult(
3048                         $dbr->select( 'page',
3049                                 [ 'page_id', 'page_namespace', 'page_title', 'page_is_redirect' ],
3050                                 $conds,
3051                                 __METHOD__,
3052                                 $options
3053                         )
3054                 );
3055                 return $this->mSubpages;
3056         }
3057
3058         /**
3059          * Is there a version of this page in the deletion archive?
3060          *
3061          * @return int The number of archived revisions
3062          */
3063         public function isDeleted() {
3064                 if ( $this->getNamespace() < 0 ) {
3065                         $n = 0;
3066                 } else {
3067                         $dbr = wfGetDB( DB_SLAVE );
3068
3069                         $n = $dbr->selectField( 'archive', 'COUNT(*)',
3070                                 [ 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ],
3071                                 __METHOD__
3072                         );
3073                         if ( $this->getNamespace() == NS_FILE ) {
3074                                 $n += $dbr->selectField( 'filearchive', 'COUNT(*)',
3075                                         [ 'fa_name' => $this->getDBkey() ],
3076                                         __METHOD__
3077                                 );
3078                         }
3079                 }
3080                 return (int)$n;
3081         }
3082
3083         /**
3084          * Is there a version of this page in the deletion archive?
3085          *
3086          * @return bool
3087          */
3088         public function isDeletedQuick() {
3089                 if ( $this->getNamespace() < 0 ) {
3090                         return false;
3091                 }
3092                 $dbr = wfGetDB( DB_SLAVE );
3093                 $deleted = (bool)$dbr->selectField( 'archive', '1',
3094                         [ 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ],
3095                         __METHOD__
3096                 );
3097                 if ( !$deleted && $this->getNamespace() == NS_FILE ) {
3098                         $deleted = (bool)$dbr->selectField( 'filearchive', '1',
3099                                 [ 'fa_name' => $this->getDBkey() ],
3100                                 __METHOD__
3101                         );
3102                 }
3103                 return $deleted;
3104         }
3105
3106         /**
3107          * Get the article ID for this Title from the link cache,
3108          * adding it if necessary
3109          *
3110          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select
3111          *  for update
3112          * @return int The ID
3113          */
3114         public function getArticleID( $flags = 0 ) {
3115                 if ( $this->getNamespace() < 0 ) {
3116                         $this->mArticleID = 0;
3117                         return $this->mArticleID;
3118                 }
3119                 $linkCache = LinkCache::singleton();
3120                 if ( $flags & self::GAID_FOR_UPDATE ) {
3121                         $oldUpdate = $linkCache->forUpdate( true );
3122                         $linkCache->clearLink( $this );
3123                         $this->mArticleID = $linkCache->addLinkObj( $this );
3124                         $linkCache->forUpdate( $oldUpdate );
3125                 } else {
3126                         if ( -1 == $this->mArticleID ) {
3127                                 $this->mArticleID = $linkCache->addLinkObj( $this );
3128                         }
3129                 }
3130                 return $this->mArticleID;
3131         }
3132
3133         /**
3134          * Is this an article that is a redirect page?
3135          * Uses link cache, adding it if necessary
3136          *
3137          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3138          * @return bool
3139          */
3140         public function isRedirect( $flags = 0 ) {
3141                 if ( !is_null( $this->mRedirect ) ) {
3142                         return $this->mRedirect;
3143                 }
3144                 if ( !$this->getArticleID( $flags ) ) {
3145                         $this->mRedirect = false;
3146                         return $this->mRedirect;
3147                 }
3148
3149                 $linkCache = LinkCache::singleton();
3150                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3151                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'redirect' );
3152                 if ( $cached === null ) {
3153                         # Trust LinkCache's state over our own
3154                         # LinkCache is telling us that the page doesn't exist, despite there being cached
3155                         # data relating to an existing page in $this->mArticleID. Updaters should clear
3156                         # LinkCache as appropriate, or use $flags = Title::GAID_FOR_UPDATE. If that flag is
3157                         # set, then LinkCache will definitely be up to date here, since getArticleID() forces
3158                         # LinkCache to refresh its data from the master.
3159                         $this->mRedirect = false;
3160                         return $this->mRedirect;
3161                 }
3162
3163                 $this->mRedirect = (bool)$cached;
3164
3165                 return $this->mRedirect;
3166         }
3167
3168         /**
3169          * What is the length of this page?
3170          * Uses link cache, adding it if necessary
3171          *
3172          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3173          * @return int
3174          */
3175         public function getLength( $flags = 0 ) {
3176                 if ( $this->mLength != -1 ) {
3177                         return $this->mLength;
3178                 }
3179                 if ( !$this->getArticleID( $flags ) ) {
3180                         $this->mLength = 0;
3181                         return $this->mLength;
3182                 }
3183                 $linkCache = LinkCache::singleton();
3184                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3185                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'length' );
3186                 if ( $cached === null ) {
3187                         # Trust LinkCache's state over our own, as for isRedirect()
3188                         $this->mLength = 0;
3189                         return $this->mLength;
3190                 }
3191
3192                 $this->mLength = intval( $cached );
3193
3194                 return $this->mLength;
3195         }
3196
3197         /**
3198          * What is the page_latest field for this page?
3199          *
3200          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3201          * @return int Int or 0 if the page doesn't exist
3202          */
3203         public function getLatestRevID( $flags = 0 ) {
3204                 if ( !( $flags & Title::GAID_FOR_UPDATE ) && $this->mLatestID !== false ) {
3205                         return intval( $this->mLatestID );
3206                 }
3207                 if ( !$this->getArticleID( $flags ) ) {
3208                         $this->mLatestID = 0;
3209                         return $this->mLatestID;
3210                 }
3211                 $linkCache = LinkCache::singleton();
3212                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3213                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'revision' );
3214                 if ( $cached === null ) {
3215                         # Trust LinkCache's state over our own, as for isRedirect()
3216                         $this->mLatestID = 0;
3217                         return $this->mLatestID;
3218                 }
3219
3220                 $this->mLatestID = intval( $cached );
3221
3222                 return $this->mLatestID;
3223         }
3224
3225         /**
3226          * This clears some fields in this object, and clears any associated
3227          * keys in the "bad links" section of the link cache.
3228          *
3229          * - This is called from WikiPage::doEdit() and WikiPage::insertOn() to allow
3230          * loading of the new page_id. It's also called from
3231          * WikiPage::doDeleteArticleReal()
3232          *
3233          * @param int $newid The new Article ID
3234          */
3235         public function resetArticleID( $newid ) {
3236                 $linkCache = LinkCache::singleton();
3237                 $linkCache->clearLink( $this );
3238
3239                 if ( $newid === false ) {
3240                         $this->mArticleID = -1;
3241                 } else {
3242                         $this->mArticleID = intval( $newid );
3243                 }
3244                 $this->mRestrictionsLoaded = false;
3245                 $this->mRestrictions = [];
3246                 $this->mOldRestrictions = false;
3247                 $this->mRedirect = null;
3248                 $this->mLength = -1;
3249                 $this->mLatestID = false;
3250                 $this->mContentModel = false;
3251                 $this->mEstimateRevisions = null;
3252                 $this->mPageLanguage = false;
3253                 $this->mDbPageLanguage = false;
3254                 $this->mIsBigDeletion = null;
3255         }
3256
3257         public static function clearCaches() {
3258                 $linkCache = LinkCache::singleton();
3259                 $linkCache->clear();
3260
3261                 $titleCache = self::getTitleCache();
3262                 $titleCache->clear();
3263         }
3264
3265         /**
3266          * Capitalize a text string for a title if it belongs to a namespace that capitalizes
3267          *
3268          * @param string $text Containing title to capitalize
3269          * @param int $ns Namespace index, defaults to NS_MAIN
3270          * @return string Containing capitalized title
3271          */
3272         public static function capitalize( $text, $ns = NS_MAIN ) {
3273                 global $wgContLang;
3274
3275                 if ( MWNamespace::isCapitalized( $ns ) ) {
3276                         return $wgContLang->ucfirst( $text );
3277                 } else {
3278                         return $text;
3279                 }
3280         }
3281
3282         /**
3283          * Secure and split - main initialisation function for this object
3284          *
3285          * Assumes that mDbkeyform has been set, and is urldecoded
3286          * and uses underscores, but not otherwise munged.  This function
3287          * removes illegal characters, splits off the interwiki and
3288          * namespace prefixes, sets the other forms, and canonicalizes
3289          * everything.
3290          *
3291          * @throws MalformedTitleException On invalid titles
3292          * @return bool True on success
3293          */
3294         private function secureAndSplit() {
3295                 # Initialisation
3296                 $this->mInterwiki = '';
3297                 $this->mFragment = '';
3298                 $this->mNamespace = $this->mDefaultNamespace; # Usually NS_MAIN
3299
3300                 $dbkey = $this->mDbkeyform;
3301
3302                 // @note: splitTitleString() is a temporary hack to allow MediaWikiTitleCodec to share
3303                 //        the parsing code with Title, while avoiding massive refactoring.
3304                 // @todo: get rid of secureAndSplit, refactor parsing code.
3305                 // @note: getTitleParser() returns a TitleParser implementation which does not have a
3306                 //        splitTitleString method, but the only implementation (MediaWikiTitleCodec) does
3307                 $titleCodec = MediaWikiServices::getInstance()->getTitleParser();
3308                 // MalformedTitleException can be thrown here
3309                 $parts = $titleCodec->splitTitleString( $dbkey, $this->getDefaultNamespace() );
3310
3311                 # Fill fields
3312                 $this->setFragment( '#' . $parts['fragment'] );
3313                 $this->mInterwiki = $parts['interwiki'];
3314                 $this->mLocalInterwiki = $parts['local_interwiki'];
3315                 $this->mNamespace = $parts['namespace'];
3316                 $this->mUserCaseDBKey = $parts['user_case_dbkey'];
3317
3318                 $this->mDbkeyform = $parts['dbkey'];
3319                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
3320                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
3321
3322                 # We already know that some pages won't be in the database!
3323                 if ( $this->isExternal() || $this->mNamespace == NS_SPECIAL ) {
3324                         $this->mArticleID = 0;
3325                 }
3326
3327                 return true;
3328         }
3329
3330         /**
3331          * Get an array of Title objects linking to this Title
3332          * Also stores the IDs in the link cache.
3333          *
3334          * WARNING: do not use this function on arbitrary user-supplied titles!
3335          * On heavily-used templates it will max out the memory.
3336          *
3337          * @param array $options May be FOR UPDATE
3338          * @param string $table Table name
3339          * @param string $prefix Fields prefix
3340          * @return Title[] Array of Title objects linking here
3341          */
3342         public function getLinksTo( $options = [], $table = 'pagelinks', $prefix = 'pl' ) {
3343                 if ( count( $options ) > 0 ) {
3344                         $db = wfGetDB( DB_MASTER );
3345                 } else {
3346                         $db = wfGetDB( DB_SLAVE );
3347                 }
3348
3349                 $res = $db->select(
3350                         [ 'page', $table ],
3351                         self::getSelectFields(),
3352                         [
3353                                 "{$prefix}_from=page_id",
3354                                 "{$prefix}_namespace" => $this->getNamespace(),
3355                                 "{$prefix}_title" => $this->getDBkey() ],
3356                         __METHOD__,
3357                         $options
3358                 );
3359
3360                 $retVal = [];
3361                 if ( $res->numRows() ) {
3362                         $linkCache = LinkCache::singleton();
3363                         foreach ( $res as $row ) {
3364                                 $titleObj = Title::makeTitle( $row->page_namespace, $row->page_title );
3365                                 if ( $titleObj ) {
3366                                         $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3367                                         $retVal[] = $titleObj;
3368                                 }
3369                         }
3370                 }
3371                 return $retVal;
3372         }
3373
3374         /**
3375          * Get an array of Title objects using this Title as a template
3376          * Also stores the IDs in the link cache.
3377          *
3378          * WARNING: do not use this function on arbitrary user-supplied titles!
3379          * On heavily-used templates it will max out the memory.
3380          *
3381          * @param array $options Query option to Database::select()
3382          * @return Title[] Array of Title the Title objects linking here
3383          */
3384         public function getTemplateLinksTo( $options = [] ) {
3385                 return $this->getLinksTo( $options, 'templatelinks', 'tl' );
3386         }
3387
3388         /**
3389          * Get an array of Title objects linked from this Title
3390          * Also stores the IDs in the link cache.
3391          *
3392          * WARNING: do not use this function on arbitrary user-supplied titles!
3393          * On heavily-used templates it will max out the memory.
3394          *
3395          * @param array $options Query option to Database::select()
3396          * @param string $table Table name
3397          * @param string $prefix Fields prefix
3398          * @return array Array of Title objects linking here
3399          */
3400         public function getLinksFrom( $options = [], $table = 'pagelinks', $prefix = 'pl' ) {
3401                 $id = $this->getArticleID();
3402
3403                 # If the page doesn't exist; there can't be any link from this page
3404                 if ( !$id ) {
3405                         return [];
3406                 }
3407
3408                 $db = wfGetDB( DB_SLAVE );
3409
3410                 $blNamespace = "{$prefix}_namespace";
3411                 $blTitle = "{$prefix}_title";
3412
3413                 $res = $db->select(
3414                         [ $table, 'page' ],
3415                         array_merge(
3416                                 [ $blNamespace, $blTitle ],
3417                                 WikiPage::selectFields()
3418                         ),
3419                         [ "{$prefix}_from" => $id ],
3420                         __METHOD__,
3421                         $options,
3422                         [ 'page' => [
3423                                 'LEFT JOIN',
3424                                 [ "page_namespace=$blNamespace", "page_title=$blTitle" ]
3425                         ] ]
3426                 );
3427
3428                 $retVal = [];
3429                 $linkCache = LinkCache::singleton();
3430                 foreach ( $res as $row ) {
3431                         if ( $row->page_id ) {
3432                                 $titleObj = Title::newFromRow( $row );
3433                         } else {
3434                                 $titleObj = Title::makeTitle( $row->$blNamespace, $row->$blTitle );
3435                                 $linkCache->addBadLinkObj( $titleObj );
3436                         }
3437                         $retVal[] = $titleObj;
3438                 }
3439
3440                 return $retVal;
3441         }
3442
3443         /**
3444          * Get an array of Title objects used on this Title as a template
3445          * Also stores the IDs in the link cache.
3446          *
3447          * WARNING: do not use this function on arbitrary user-supplied titles!
3448          * On heavily-used templates it will max out the memory.
3449          *
3450          * @param array $options May be FOR UPDATE
3451          * @return Title[] Array of Title the Title objects used here
3452          */
3453         public function getTemplateLinksFrom( $options = [] ) {
3454                 return $this->getLinksFrom( $options, 'templatelinks', 'tl' );
3455         }
3456
3457         /**
3458          * Get an array of Title objects referring to non-existent articles linked
3459          * from this page.
3460          *
3461          * @todo check if needed (used only in SpecialBrokenRedirects.php, and
3462          *   should use redirect table in this case).
3463          * @return Title[] Array of Title the Title objects
3464          */
3465         public function getBrokenLinksFrom() {
3466                 if ( $this->getArticleID() == 0 ) {
3467                         # All links from article ID 0 are false positives
3468                         return [];
3469                 }
3470
3471                 $dbr = wfGetDB( DB_SLAVE );
3472                 $res = $dbr->select(
3473                         [ 'page', 'pagelinks' ],
3474                         [ 'pl_namespace', 'pl_title' ],
3475                         [
3476                                 'pl_from' => $this->getArticleID(),
3477                                 'page_namespace IS NULL'
3478                         ],
3479                         __METHOD__, [],
3480                         [
3481                                 'page' => [
3482                                         'LEFT JOIN',
3483                                         [ 'pl_namespace=page_namespace', 'pl_title=page_title' ]
3484                                 ]
3485                         ]
3486                 );
3487
3488                 $retVal = [];
3489                 foreach ( $res as $row ) {
3490                         $retVal[] = Title::makeTitle( $row->pl_namespace, $row->pl_title );
3491                 }
3492                 return $retVal;
3493         }
3494
3495         /**
3496          * Get a list of URLs to purge from the CDN cache when this
3497          * page changes
3498          *
3499          * @return string[] Array of String the URLs
3500          */
3501         public function getCdnUrls() {
3502                 $urls = [
3503                         $this->getInternalURL(),
3504                         $this->getInternalURL( 'action=history' )
3505                 ];
3506
3507                 $pageLang = $this->getPageLanguage();
3508                 if ( $pageLang->hasVariants() ) {
3509                         $variants = $pageLang->getVariants();
3510                         foreach ( $variants as $vCode ) {
3511                                 $urls[] = $this->getInternalURL( $vCode );
3512                         }
3513                 }
3514
3515                 // If we are looking at a css/js user subpage, purge the action=raw.
3516                 if ( $this->isJsSubpage() ) {
3517                         $urls[] = $this->getInternalURL( 'action=raw&ctype=text/javascript' );
3518                 } elseif ( $this->isCssSubpage() ) {
3519                         $urls[] = $this->getInternalURL( 'action=raw&ctype=text/css' );
3520                 }
3521
3522                 Hooks::run( 'TitleSquidURLs', [ $this, &$urls ] );
3523                 return $urls;
3524         }
3525
3526         /**
3527          * @deprecated since 1.27 use getCdnUrls()
3528          */
3529         public function getSquidURLs() {
3530                 return $this->getCdnUrls();
3531         }
3532
3533         /**
3534          * Purge all applicable CDN URLs
3535          */
3536         public function purgeSquid() {
3537                 DeferredUpdates::addUpdate(
3538                         new CdnCacheUpdate( $this->getCdnUrls() ),
3539                         DeferredUpdates::PRESEND
3540                 );
3541         }
3542
3543         /**
3544          * Move this page without authentication
3545          *
3546          * @deprecated since 1.25 use MovePage class instead
3547          * @param Title $nt The new page Title
3548          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3549          */
3550         public function moveNoAuth( &$nt ) {
3551                 wfDeprecated( __METHOD__, '1.25' );
3552                 return $this->moveTo( $nt, false );
3553         }
3554
3555         /**
3556          * Check whether a given move operation would be valid.
3557          * Returns true if ok, or a getUserPermissionsErrors()-like array otherwise
3558          *
3559          * @deprecated since 1.25, use MovePage's methods instead
3560          * @param Title $nt The new title
3561          * @param bool $auth Whether to check user permissions (uses $wgUser)
3562          * @param string $reason Is the log summary of the move, used for spam checking
3563          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3564          */
3565         public function isValidMoveOperation( &$nt, $auth = true, $reason = '' ) {
3566                 global $wgUser;
3567
3568                 if ( !( $nt instanceof Title ) ) {
3569                         // Normally we'd add this to $errors, but we'll get
3570                         // lots of syntax errors if $nt is not an object
3571                         return [ [ 'badtitletext' ] ];
3572                 }
3573
3574                 $mp = new MovePage( $this, $nt );
3575                 $errors = $mp->isValidMove()->getErrorsArray();
3576                 if ( $auth ) {
3577                         $errors = wfMergeErrorArrays(
3578                                 $errors,
3579                                 $mp->checkPermissions( $wgUser, $reason )->getErrorsArray()
3580                         );
3581                 }
3582
3583                 return $errors ?: true;
3584         }
3585
3586         /**
3587          * Check if the requested move target is a valid file move target
3588          * @todo move this to MovePage
3589          * @param Title $nt Target title
3590          * @return array List of errors
3591          */
3592         protected function validateFileMoveOperation( $nt ) {
3593                 global $wgUser;
3594
3595                 $errors = [];
3596
3597                 $destFile = wfLocalFile( $nt );
3598                 $destFile->load( File::READ_LATEST );
3599                 if ( !$wgUser->isAllowed( 'reupload-shared' )
3600                         && !$destFile->exists() && wfFindFile( $nt )
3601                 ) {
3602                         $errors[] = [ 'file-exists-sharedrepo' ];
3603                 }
3604
3605                 return $errors;
3606         }
3607
3608         /**
3609          * Move a title to a new location
3610          *
3611          * @deprecated since 1.25, use the MovePage class instead
3612          * @param Title $nt The new title
3613          * @param bool $auth Indicates whether $wgUser's permissions
3614          *  should be checked
3615          * @param string $reason The reason for the move
3616          * @param bool $createRedirect Whether to create a redirect from the old title to the new title.
3617          *  Ignored if the user doesn't have the suppressredirect right.
3618          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3619          */
3620         public function moveTo( &$nt, $auth = true, $reason = '', $createRedirect = true ) {
3621                 global $wgUser;
3622                 $err = $this->isValidMoveOperation( $nt, $auth, $reason );
3623                 if ( is_array( $err ) ) {
3624                         // Auto-block user's IP if the account was "hard" blocked
3625                         $wgUser->spreadAnyEditBlock();
3626                         return $err;
3627                 }
3628                 // Check suppressredirect permission
3629                 if ( $auth && !$wgUser->isAllowed( 'suppressredirect' ) ) {
3630                         $createRedirect = true;
3631                 }
3632
3633                 $mp = new MovePage( $this, $nt );
3634                 $status = $mp->move( $wgUser, $reason, $createRedirect );
3635                 if ( $status->isOK() ) {
3636                         return true;
3637                 } else {
3638                         return $status->getErrorsArray();
3639                 }
3640         }
3641
3642         /**
3643          * Move this page's subpages to be subpages of $nt
3644          *
3645          * @param Title $nt Move target
3646          * @param bool $auth Whether $wgUser's permissions should be checked
3647          * @param string $reason The reason for the move
3648          * @param bool $createRedirect Whether to create redirects from the old subpages to
3649          *     the new ones Ignored if the user doesn't have the 'suppressredirect' right
3650          * @return array Array with old page titles as keys, and strings (new page titles) or
3651          *     arrays (errors) as values, or an error array with numeric indices if no pages
3652          *     were moved
3653          */
3654         public function moveSubpages( $nt, $auth = true, $reason = '', $createRedirect = true ) {
3655                 global $wgMaximumMovedPages;
3656                 // Check permissions
3657                 if ( !$this->userCan( 'move-subpages' ) ) {
3658                         return [ 'cant-move-subpages' ];
3659                 }
3660                 // Do the source and target namespaces support subpages?
3661                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3662                         return [ 'namespace-nosubpages',
3663                                 MWNamespace::getCanonicalName( $this->getNamespace() ) ];
3664                 }
3665                 if ( !MWNamespace::hasSubpages( $nt->getNamespace() ) ) {
3666                         return [ 'namespace-nosubpages',
3667                                 MWNamespace::getCanonicalName( $nt->getNamespace() ) ];
3668                 }
3669
3670                 $subpages = $this->getSubpages( $wgMaximumMovedPages + 1 );
3671                 $retval = [];
3672                 $count = 0;
3673                 foreach ( $subpages as $oldSubpage ) {
3674                         $count++;
3675                         if ( $count > $wgMaximumMovedPages ) {
3676                                 $retval[$oldSubpage->getPrefixedText()] =
3677                                                 [ 'movepage-max-pages',
3678                                                         $wgMaximumMovedPages ];
3679                                 break;
3680                         }
3681
3682                         // We don't know whether this function was called before
3683                         // or after moving the root page, so check both
3684                         // $this and $nt
3685                         if ( $oldSubpage->getArticleID() == $this->getArticleID()
3686                                 || $oldSubpage->getArticleID() == $nt->getArticleID()
3687                         ) {
3688                                 // When moving a page to a subpage of itself,
3689                                 // don't move it twice
3690                                 continue;
3691                         }
3692                         $newPageName = preg_replace(
3693                                         '#^' . preg_quote( $this->getDBkey(), '#' ) . '#',
3694                                         StringUtils::escapeRegexReplacement( $nt->getDBkey() ), # bug 21234
3695                                         $oldSubpage->getDBkey() );
3696                         if ( $oldSubpage->isTalkPage() ) {
3697                                 $newNs = $nt->getTalkPage()->getNamespace();
3698                         } else {
3699                                 $newNs = $nt->getSubjectPage()->getNamespace();
3700                         }
3701                         # Bug 14385: we need makeTitleSafe because the new page names may
3702                         # be longer than 255 characters.
3703                         $newSubpage = Title::makeTitleSafe( $newNs, $newPageName );
3704
3705                         $success = $oldSubpage->moveTo( $newSubpage, $auth, $reason, $createRedirect );
3706                         if ( $success === true ) {
3707                                 $retval[$oldSubpage->getPrefixedText()] = $newSubpage->getPrefixedText();
3708                         } else {
3709                                 $retval[$oldSubpage->getPrefixedText()] = $success;
3710                         }
3711                 }
3712                 return $retval;
3713         }
3714
3715         /**
3716          * Checks if this page is just a one-rev redirect.
3717          * Adds lock, so don't use just for light purposes.
3718          *
3719          * @return bool
3720          */
3721         public function isSingleRevRedirect() {
3722                 global $wgContentHandlerUseDB;
3723
3724                 $dbw = wfGetDB( DB_MASTER );
3725
3726                 # Is it a redirect?
3727                 $fields = [ 'page_is_redirect', 'page_latest', 'page_id' ];
3728                 if ( $wgContentHandlerUseDB ) {
3729                         $fields[] = 'page_content_model';
3730                 }
3731
3732                 $row = $dbw->selectRow( 'page',
3733                         $fields,
3734                         $this->pageCond(),
3735                         __METHOD__,
3736                         [ 'FOR UPDATE' ]
3737                 );
3738                 # Cache some fields we may want
3739                 $this->mArticleID = $row ? intval( $row->page_id ) : 0;
3740                 $this->mRedirect = $row ? (bool)$row->page_is_redirect : false;
3741                 $this->mLatestID = $row ? intval( $row->page_latest ) : false;
3742                 $this->mContentModel = $row && isset( $row->page_content_model )
3743                         ? strval( $row->page_content_model )
3744                         : false;
3745
3746                 if ( !$this->mRedirect ) {
3747                         return false;
3748                 }
3749                 # Does the article have a history?
3750                 $row = $dbw->selectField( [ 'page', 'revision' ],
3751                         'rev_id',
3752                         [ 'page_namespace' => $this->getNamespace(),
3753                                 'page_title' => $this->getDBkey(),
3754                                 'page_id=rev_page',
3755                                 'page_latest != rev_id'
3756                         ],
3757                         __METHOD__,
3758                         [ 'FOR UPDATE' ]
3759                 );
3760                 # Return true if there was no history
3761                 return ( $row === false );
3762         }
3763
3764         /**
3765          * Checks if $this can be moved to a given Title
3766          * - Selects for update, so don't call it unless you mean business
3767          *
3768          * @deprecated since 1.25, use MovePage's methods instead
3769          * @param Title $nt The new title to check
3770          * @return bool
3771          */
3772         public function isValidMoveTarget( $nt ) {
3773                 # Is it an existing file?
3774                 if ( $nt->getNamespace() == NS_FILE ) {
3775                         $file = wfLocalFile( $nt );
3776                         $file->load( File::READ_LATEST );
3777                         if ( $file->exists() ) {
3778                                 wfDebug( __METHOD__ . ": file exists\n" );
3779                                 return false;
3780                         }
3781                 }
3782                 # Is it a redirect with no history?
3783                 if ( !$nt->isSingleRevRedirect() ) {
3784                         wfDebug( __METHOD__ . ": not a one-rev redirect\n" );
3785                         return false;
3786                 }
3787                 # Get the article text
3788                 $rev = Revision::newFromTitle( $nt, false, Revision::READ_LATEST );
3789                 if ( !is_object( $rev ) ) {
3790                         return false;
3791                 }
3792                 $content = $rev->getContent();
3793                 # Does the redirect point to the source?
3794                 # Or is it a broken self-redirect, usually caused by namespace collisions?
3795                 $redirTitle = $content ? $content->getRedirectTarget() : null;
3796
3797                 if ( $redirTitle ) {
3798                         if ( $redirTitle->getPrefixedDBkey() != $this->getPrefixedDBkey() &&
3799                                 $redirTitle->getPrefixedDBkey() != $nt->getPrefixedDBkey() ) {
3800                                 wfDebug( __METHOD__ . ": redirect points to other page\n" );
3801                                 return false;
3802                         } else {
3803                                 return true;
3804                         }
3805                 } else {
3806                         # Fail safe (not a redirect after all. strange.)
3807                         wfDebug( __METHOD__ . ": failsafe: database sais " . $nt->getPrefixedDBkey() .
3808                                                 " is a redirect, but it doesn't contain a valid redirect.\n" );
3809                         return false;
3810                 }
3811         }
3812
3813         /**
3814          * Get categories to which this Title belongs and return an array of
3815          * categories' names.
3816          *
3817          * @return array Array of parents in the form:
3818          *        $parent => $currentarticle
3819          */
3820         public function getParentCategories() {
3821                 global $wgContLang;
3822
3823                 $data = [];
3824
3825                 $titleKey = $this->getArticleID();
3826
3827                 if ( $titleKey === 0 ) {
3828                         return $data;
3829                 }
3830
3831                 $dbr = wfGetDB( DB_SLAVE );
3832
3833                 $res = $dbr->select(
3834                         'categorylinks',
3835                         'cl_to',
3836                         [ 'cl_from' => $titleKey ],
3837                         __METHOD__
3838                 );
3839
3840                 if ( $res->numRows() > 0 ) {
3841                         foreach ( $res as $row ) {
3842                                 // $data[] = Title::newFromText($wgContLang->getNsText ( NS_CATEGORY ).':'.$row->cl_to);
3843                                 $data[$wgContLang->getNsText( NS_CATEGORY ) . ':' . $row->cl_to] = $this->getFullText();
3844                         }
3845                 }
3846                 return $data;
3847         }
3848
3849         /**
3850          * Get a tree of parent categories
3851          *
3852          * @param array $children Array with the children in the keys, to check for circular refs
3853          * @return array Tree of parent categories
3854          */
3855         public function getParentCategoryTree( $children = [] ) {
3856                 $stack = [];
3857                 $parents = $this->getParentCategories();
3858
3859                 if ( $parents ) {
3860                         foreach ( $parents as $parent => $current ) {
3861                                 if ( array_key_exists( $parent, $children ) ) {
3862                                         # Circular reference
3863                                         $stack[$parent] = [];
3864                                 } else {
3865                                         $nt = Title::newFromText( $parent );
3866                                         if ( $nt ) {
3867                                                 $stack[$parent] = $nt->getParentCategoryTree( $children + [ $parent => 1 ] );
3868                                         }
3869                                 }
3870                         }
3871                 }
3872
3873                 return $stack;
3874         }
3875
3876         /**
3877          * Get an associative array for selecting this title from
3878          * the "page" table
3879          *
3880          * @return array Array suitable for the $where parameter of DB::select()
3881          */
3882         public function pageCond() {
3883                 if ( $this->mArticleID > 0 ) {
3884                         // PK avoids secondary lookups in InnoDB, shouldn't hurt other DBs
3885                         return [ 'page_id' => $this->mArticleID ];
3886                 } else {
3887                         return [ 'page_namespace' => $this->mNamespace, 'page_title' => $this->mDbkeyform ];
3888                 }
3889         }
3890
3891         /**
3892          * Get the revision ID of the previous revision
3893          *
3894          * @param int $revId Revision ID. Get the revision that was before this one.
3895          * @param int $flags Title::GAID_FOR_UPDATE
3896          * @return int|bool Old revision ID, or false if none exists
3897          */
3898         public function getPreviousRevisionID( $revId, $flags = 0 ) {
3899                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
3900                 $revId = $db->selectField( 'revision', 'rev_id',
3901                         [
3902                                 'rev_page' => $this->getArticleID( $flags ),
3903                                 'rev_id < ' . intval( $revId )
3904                         ],
3905                         __METHOD__,
3906                         [ 'ORDER BY' => 'rev_id DESC' ]
3907                 );
3908
3909                 if ( $revId === false ) {
3910                         return false;
3911                 } else {
3912                         return intval( $revId );
3913                 }
3914         }
3915
3916         /**
3917          * Get the revision ID of the next revision
3918          *
3919          * @param int $revId Revision ID. Get the revision that was after this one.
3920          * @param int $flags Title::GAID_FOR_UPDATE
3921          * @return int|bool Next revision ID, or false if none exists
3922          */
3923         public function getNextRevisionID( $revId, $flags = 0 ) {
3924                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
3925                 $revId = $db->selectField( 'revision', 'rev_id',
3926                         [
3927                                 'rev_page' => $this->getArticleID( $flags ),
3928                                 'rev_id > ' . intval( $revId )
3929                         ],
3930                         __METHOD__,
3931                         [ 'ORDER BY' => 'rev_id' ]
3932                 );
3933
3934                 if ( $revId === false ) {
3935                         return false;
3936                 } else {
3937                         return intval( $revId );
3938                 }
3939         }
3940
3941         /**
3942          * Get the first revision of the page
3943          *
3944          * @param int $flags Title::GAID_FOR_UPDATE
3945          * @return Revision|null If page doesn't exist
3946          */
3947         public function getFirstRevision( $flags = 0 ) {
3948                 $pageId = $this->getArticleID( $flags );
3949                 if ( $pageId ) {
3950                         $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
3951                         $row = $db->selectRow( 'revision', Revision::selectFields(),
3952                                 [ 'rev_page' => $pageId ],
3953                                 __METHOD__,
3954                                 [ 'ORDER BY' => 'rev_timestamp ASC', 'LIMIT' => 1 ]
3955                         );
3956                         if ( $row ) {
3957                                 return new Revision( $row );
3958                         }
3959                 }
3960                 return null;
3961         }
3962
3963         /**
3964          * Get the oldest revision timestamp of this page
3965          *
3966          * @param int $flags Title::GAID_FOR_UPDATE
3967          * @return string MW timestamp
3968          */
3969         public function getEarliestRevTime( $flags = 0 ) {
3970                 $rev = $this->getFirstRevision( $flags );
3971                 return $rev ? $rev->getTimestamp() : null;
3972         }
3973
3974         /**
3975          * Check if this is a new page
3976          *
3977          * @return bool
3978          */
3979         public function isNewPage() {
3980                 $dbr = wfGetDB( DB_SLAVE );
3981                 return (bool)$dbr->selectField( 'page', 'page_is_new', $this->pageCond(), __METHOD__ );
3982         }
3983
3984         /**
3985          * Check whether the number of revisions of this page surpasses $wgDeleteRevisionsLimit
3986          *
3987          * @return bool
3988          */
3989         public function isBigDeletion() {
3990                 global $wgDeleteRevisionsLimit;
3991
3992                 if ( !$wgDeleteRevisionsLimit ) {
3993                         return false;
3994                 }
3995
3996                 if ( $this->mIsBigDeletion === null ) {
3997                         $dbr = wfGetDB( DB_SLAVE );
3998
3999                         $revCount = $dbr->selectRowCount(
4000                                 'revision',
4001                                 '1',
4002                                 [ 'rev_page' => $this->getArticleID() ],
4003                                 __METHOD__,
4004                                 [ 'LIMIT' => $wgDeleteRevisionsLimit + 1 ]
4005                         );
4006
4007                         $this->mIsBigDeletion = $revCount > $wgDeleteRevisionsLimit;
4008                 }
4009
4010                 return $this->mIsBigDeletion;
4011         }
4012
4013         /**
4014          * Get the approximate revision count of this page.
4015          *
4016          * @return int
4017          */
4018         public function estimateRevisionCount() {
4019                 if ( !$this->exists() ) {
4020                         return 0;
4021                 }
4022
4023                 if ( $this->mEstimateRevisions === null ) {
4024                         $dbr = wfGetDB( DB_SLAVE );
4025                         $this->mEstimateRevisions = $dbr->estimateRowCount( 'revision', '*',
4026                                 [ 'rev_page' => $this->getArticleID() ], __METHOD__ );
4027                 }
4028
4029                 return $this->mEstimateRevisions;
4030         }
4031
4032         /**
4033          * Get the number of revisions between the given revision.
4034          * Used for diffs and other things that really need it.
4035          *
4036          * @param int|Revision $old Old revision or rev ID (first before range)
4037          * @param int|Revision $new New revision or rev ID (first after range)
4038          * @param int|null $max Limit of Revisions to count, will be incremented to detect truncations
4039          * @return int Number of revisions between these revisions.
4040          */
4041         public function countRevisionsBetween( $old, $new, $max = null ) {
4042                 if ( !( $old instanceof Revision ) ) {
4043                         $old = Revision::newFromTitle( $this, (int)$old );
4044                 }
4045                 if ( !( $new instanceof Revision ) ) {
4046                         $new = Revision::newFromTitle( $this, (int)$new );
4047                 }
4048                 if ( !$old || !$new ) {
4049                         return 0; // nothing to compare
4050                 }
4051                 $dbr = wfGetDB( DB_SLAVE );
4052                 $conds = [
4053                         'rev_page' => $this->getArticleID(),
4054                         'rev_timestamp > ' . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4055                         'rev_timestamp < ' . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4056                 ];
4057                 if ( $max !== null ) {
4058                         return $dbr->selectRowCount( 'revision', '1',
4059                                 $conds,
4060                                 __METHOD__,
4061                                 [ 'LIMIT' => $max + 1 ] // extra to detect truncation
4062                         );
4063                 } else {
4064                         return (int)$dbr->selectField( 'revision', 'count(*)', $conds, __METHOD__ );
4065                 }
4066         }
4067
4068         /**
4069          * Get the authors between the given revisions or revision IDs.
4070          * Used for diffs and other things that really need it.
4071          *
4072          * @since 1.23
4073          *
4074          * @param int|Revision $old Old revision or rev ID (first before range by default)
4075          * @param int|Revision $new New revision or rev ID (first after range by default)
4076          * @param int $limit Maximum number of authors
4077          * @param string|array $options (Optional): Single option, or an array of options:
4078          *     'include_old' Include $old in the range; $new is excluded.
4079          *     'include_new' Include $new in the range; $old is excluded.
4080          *     'include_both' Include both $old and $new in the range.
4081          *     Unknown option values are ignored.
4082          * @return array|null Names of revision authors in the range; null if not both revisions exist
4083          */
4084         public function getAuthorsBetween( $old, $new, $limit, $options = [] ) {
4085                 if ( !( $old instanceof Revision ) ) {
4086                         $old = Revision::newFromTitle( $this, (int)$old );
4087                 }
4088                 if ( !( $new instanceof Revision ) ) {
4089                         $new = Revision::newFromTitle( $this, (int)$new );
4090                 }
4091                 // XXX: what if Revision objects are passed in, but they don't refer to this title?
4092                 // Add $old->getPage() != $new->getPage() || $old->getPage() != $this->getArticleID()
4093                 // in the sanity check below?
4094                 if ( !$old || !$new ) {
4095                         return null; // nothing to compare
4096                 }
4097                 $authors = [];
4098                 $old_cmp = '>';
4099                 $new_cmp = '<';
4100                 $options = (array)$options;
4101                 if ( in_array( 'include_old', $options ) ) {
4102                         $old_cmp = '>=';
4103                 }
4104                 if ( in_array( 'include_new', $options ) ) {
4105                         $new_cmp = '<=';
4106                 }
4107                 if ( in_array( 'include_both', $options ) ) {
4108                         $old_cmp = '>=';
4109                         $new_cmp = '<=';
4110                 }
4111                 // No DB query needed if $old and $new are the same or successive revisions:
4112                 if ( $old->getId() === $new->getId() ) {
4113                         return ( $old_cmp === '>' && $new_cmp === '<' ) ?
4114                                 [] :
4115                                 [ $old->getUserText( Revision::RAW ) ];
4116                 } elseif ( $old->getId() === $new->getParentId() ) {
4117                         if ( $old_cmp === '>=' && $new_cmp === '<=' ) {
4118                                 $authors[] = $old->getUserText( Revision::RAW );
4119                                 if ( $old->getUserText( Revision::RAW ) != $new->getUserText( Revision::RAW ) ) {
4120                                         $authors[] = $new->getUserText( Revision::RAW );
4121                                 }
4122                         } elseif ( $old_cmp === '>=' ) {
4123                                 $authors[] = $old->getUserText( Revision::RAW );
4124                         } elseif ( $new_cmp === '<=' ) {
4125                                 $authors[] = $new->getUserText( Revision::RAW );
4126                         }
4127                         return $authors;
4128                 }
4129                 $dbr = wfGetDB( DB_SLAVE );
4130                 $res = $dbr->select( 'revision', 'DISTINCT rev_user_text',
4131                         [
4132                                 'rev_page' => $this->getArticleID(),
4133                                 "rev_timestamp $old_cmp " . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4134                                 "rev_timestamp $new_cmp " . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4135                         ], __METHOD__,
4136                         [ 'LIMIT' => $limit + 1 ] // add one so caller knows it was truncated
4137                 );
4138                 foreach ( $res as $row ) {
4139                         $authors[] = $row->rev_user_text;
4140                 }
4141                 return $authors;
4142         }
4143
4144         /**
4145          * Get the number of authors between the given revisions or revision IDs.
4146          * Used for diffs and other things that really need it.
4147          *
4148          * @param int|Revision $old Old revision or rev ID (first before range by default)
4149          * @param int|Revision $new New revision or rev ID (first after range by default)
4150          * @param int $limit Maximum number of authors
4151          * @param string|array $options (Optional): Single option, or an array of options:
4152          *     'include_old' Include $old in the range; $new is excluded.
4153          *     'include_new' Include $new in the range; $old is excluded.
4154          *     'include_both' Include both $old and $new in the range.
4155          *     Unknown option values are ignored.
4156          * @return int Number of revision authors in the range; zero if not both revisions exist
4157          */
4158         public function countAuthorsBetween( $old, $new, $limit, $options = [] ) {
4159                 $authors = $this->getAuthorsBetween( $old, $new, $limit, $options );
4160                 return $authors ? count( $authors ) : 0;
4161         }
4162
4163         /**
4164          * Compare with another title.
4165          *
4166          * @param Title $title
4167          * @return bool
4168          */
4169         public function equals( Title $title ) {
4170                 // Note: === is necessary for proper matching of number-like titles.
4171                 return $this->getInterwiki() === $title->getInterwiki()
4172                         && $this->getNamespace() == $title->getNamespace()
4173                         && $this->getDBkey() === $title->getDBkey();
4174         }
4175
4176         /**
4177          * Check if this title is a subpage of another title
4178          *
4179          * @param Title $title
4180          * @return bool
4181          */
4182         public function isSubpageOf( Title $title ) {
4183                 return $this->getInterwiki() === $title->getInterwiki()
4184                         && $this->getNamespace() == $title->getNamespace()
4185                         && strpos( $this->getDBkey(), $title->getDBkey() . '/' ) === 0;
4186         }
4187
4188         /**
4189          * Check if page exists.  For historical reasons, this function simply
4190          * checks for the existence of the title in the page table, and will
4191          * thus return false for interwiki links, special pages and the like.
4192          * If you want to know if a title can be meaningfully viewed, you should
4193          * probably call the isKnown() method instead.
4194          *
4195          * @param int $flags An optional bit field; may be Title::GAID_FOR_UPDATE to check
4196          *   from master/for update
4197          * @return bool
4198          */
4199         public function exists( $flags = 0 ) {
4200                 $exists = $this->getArticleID( $flags ) != 0;
4201                 Hooks::run( 'TitleExists', [ $this, &$exists ] );
4202                 return $exists;
4203         }
4204
4205         /**
4206          * Should links to this title be shown as potentially viewable (i.e. as
4207          * "bluelinks"), even if there's no record by this title in the page
4208          * table?
4209          *
4210          * This function is semi-deprecated for public use, as well as somewhat
4211          * misleadingly named.  You probably just want to call isKnown(), which
4212          * calls this function internally.
4213          *
4214          * (ISSUE: Most of these checks are cheap, but the file existence check
4215          * can potentially be quite expensive.  Including it here fixes a lot of
4216          * existing code, but we might want to add an optional parameter to skip
4217          * it and any other expensive checks.)
4218          *
4219          * @return bool
4220          */
4221         public function isAlwaysKnown() {
4222                 $isKnown = null;
4223
4224                 /**
4225                  * Allows overriding default behavior for determining if a page exists.
4226                  * If $isKnown is kept as null, regular checks happen. If it's
4227                  * a boolean, this value is returned by the isKnown method.
4228                  *
4229                  * @since 1.20
4230                  *
4231                  * @param Title $title
4232                  * @param bool|null $isKnown
4233                  */
4234                 Hooks::run( 'TitleIsAlwaysKnown', [ $this, &$isKnown ] );
4235
4236                 if ( !is_null( $isKnown ) ) {
4237                         return $isKnown;
4238                 }
4239
4240                 if ( $this->isExternal() ) {
4241                         return true;  // any interwiki link might be viewable, for all we know
4242                 }
4243
4244                 switch ( $this->mNamespace ) {
4245                         case NS_MEDIA:
4246                         case NS_FILE:
4247                                 // file exists, possibly in a foreign repo
4248                                 return (bool)wfFindFile( $this );
4249                         case NS_SPECIAL:
4250                                 // valid special page
4251                                 return SpecialPageFactory::exists( $this->getDBkey() );
4252                         case NS_MAIN:
4253                                 // selflink, possibly with fragment
4254                                 return $this->mDbkeyform == '';
4255                         case NS_MEDIAWIKI:
4256                                 // known system message
4257                                 return $this->hasSourceText() !== false;
4258                         default:
4259                                 return false;
4260                 }
4261         }
4262
4263         /**
4264          * Does this title refer to a page that can (or might) be meaningfully
4265          * viewed?  In particular, this function may be used to determine if
4266          * links to the title should be rendered as "bluelinks" (as opposed to
4267          * "redlinks" to non-existent pages).
4268          * Adding something else to this function will cause inconsistency
4269          * since LinkHolderArray calls isAlwaysKnown() and does its own
4270          * page existence check.
4271          *
4272          * @return bool
4273          */
4274         public function isKnown() {
4275                 return $this->isAlwaysKnown() || $this->exists();
4276         }
4277
4278         /**
4279          * Does this page have source text?
4280          *
4281          * @return bool
4282          */
4283         public function hasSourceText() {
4284                 if ( $this->exists() ) {
4285                         return true;
4286                 }
4287
4288                 if ( $this->mNamespace == NS_MEDIAWIKI ) {
4289                         // If the page doesn't exist but is a known system message, default
4290                         // message content will be displayed, same for language subpages-
4291                         // Use always content language to avoid loading hundreds of languages
4292                         // to get the link color.
4293                         global $wgContLang;
4294                         list( $name, ) = MessageCache::singleton()->figureMessage(
4295                                 $wgContLang->lcfirst( $this->getText() )
4296                         );
4297                         $message = wfMessage( $name )->inLanguage( $wgContLang )->useDatabase( false );
4298                         return $message->exists();
4299                 }
4300
4301                 return false;
4302         }
4303
4304         /**
4305          * Get the default message text or false if the message doesn't exist
4306          *
4307          * @return string|bool
4308          */
4309         public function getDefaultMessageText() {
4310                 global $wgContLang;
4311
4312                 if ( $this->getNamespace() != NS_MEDIAWIKI ) { // Just in case
4313                         return false;
4314                 }
4315
4316                 list( $name, $lang ) = MessageCache::singleton()->figureMessage(
4317                         $wgContLang->lcfirst( $this->getText() )
4318                 );
4319                 $message = wfMessage( $name )->inLanguage( $lang )->useDatabase( false );
4320
4321                 if ( $message->exists() ) {
4322                         return $message->plain();
4323                 } else {
4324                         return false;
4325                 }
4326         }
4327
4328         /**
4329          * Updates page_touched for this page; called from LinksUpdate.php
4330          *
4331          * @param string $purgeTime [optional] TS_MW timestamp
4332          * @return bool True if the update succeeded
4333          */
4334         public function invalidateCache( $purgeTime = null ) {
4335                 if ( wfReadOnly() ) {
4336                         return false;
4337                 }
4338
4339                 if ( $this->mArticleID === 0 ) {
4340                         return true; // avoid gap locking if we know it's not there
4341                 }
4342
4343                 $method = __METHOD__;
4344                 $dbw = wfGetDB( DB_MASTER );
4345                 $conds = $this->pageCond();
4346                 $dbw->onTransactionIdle( function () use ( $dbw, $conds, $method, $purgeTime ) {
4347                         $dbTimestamp = $dbw->timestamp( $purgeTime ?: time() );
4348
4349                         $dbw->update(
4350                                 'page',
4351                                 [ 'page_touched' => $dbTimestamp ],
4352                                 $conds + [ 'page_touched < ' . $dbw->addQuotes( $dbTimestamp ) ],
4353                                 $method
4354                         );
4355                 } );
4356
4357                 return true;
4358         }
4359
4360         /**
4361          * Update page_touched timestamps and send CDN purge messages for
4362          * pages linking to this title. May be sent to the job queue depending
4363          * on the number of links. Typically called on create and delete.
4364          */
4365         public function touchLinks() {
4366                 DeferredUpdates::addUpdate( new HTMLCacheUpdate( $this, 'pagelinks' ) );
4367                 if ( $this->getNamespace() == NS_CATEGORY ) {
4368                         DeferredUpdates::addUpdate( new HTMLCacheUpdate( $this, 'categorylinks' ) );
4369                 }
4370         }
4371
4372         /**
4373          * Get the last touched timestamp
4374          *
4375          * @param IDatabase $db Optional db
4376          * @return string Last-touched timestamp
4377          */
4378         public function getTouched( $db = null ) {
4379                 if ( $db === null ) {
4380                         $db = wfGetDB( DB_SLAVE );
4381                 }
4382                 $touched = $db->selectField( 'page', 'page_touched', $this->pageCond(), __METHOD__ );
4383                 return $touched;
4384         }
4385
4386         /**
4387          * Get the timestamp when this page was updated since the user last saw it.
4388          *
4389          * @param User $user
4390          * @return string|null
4391          */
4392         public function getNotificationTimestamp( $user = null ) {
4393                 global $wgUser;
4394
4395                 // Assume current user if none given
4396                 if ( !$user ) {
4397                         $user = $wgUser;
4398                 }
4399                 // Check cache first
4400                 $uid = $user->getId();
4401                 if ( !$uid ) {
4402                         return false;
4403                 }
4404                 // avoid isset here, as it'll return false for null entries
4405                 if ( array_key_exists( $uid, $this->mNotificationTimestamp ) ) {
4406                         return $this->mNotificationTimestamp[$uid];
4407                 }
4408                 // Don't cache too much!
4409                 if ( count( $this->mNotificationTimestamp ) >= self::CACHE_MAX ) {
4410                         $this->mNotificationTimestamp = [];
4411                 }
4412
4413                 $store = MediaWikiServices::getInstance()->getWatchedItemStore();
4414                 $watchedItem = $store->getWatchedItem( $user, $this );
4415                 if ( $watchedItem ) {
4416                         $this->mNotificationTimestamp[$uid] = $watchedItem->getNotificationTimestamp();
4417                 } else {
4418                         $this->mNotificationTimestamp[$uid] = false;
4419                 }
4420
4421                 return $this->mNotificationTimestamp[$uid];
4422         }
4423
4424         /**
4425          * Generate strings used for xml 'id' names in monobook tabs
4426          *
4427          * @param string $prepend Defaults to 'nstab-'
4428          * @return string XML 'id' name
4429          */
4430         public function getNamespaceKey( $prepend = 'nstab-' ) {
4431                 global $wgContLang;
4432                 // Gets the subject namespace if this title
4433                 $namespace = MWNamespace::getSubject( $this->getNamespace() );
4434                 // Checks if canonical namespace name exists for namespace
4435                 if ( MWNamespace::exists( $this->getNamespace() ) ) {
4436                         // Uses canonical namespace name
4437                         $namespaceKey = MWNamespace::getCanonicalName( $namespace );
4438                 } else {
4439                         // Uses text of namespace
4440                         $namespaceKey = $this->getSubjectNsText();
4441                 }
4442                 // Makes namespace key lowercase
4443                 $namespaceKey = $wgContLang->lc( $namespaceKey );
4444                 // Uses main
4445                 if ( $namespaceKey == '' ) {
4446                         $namespaceKey = 'main';
4447                 }
4448                 // Changes file to image for backwards compatibility
4449                 if ( $namespaceKey == 'file' ) {
4450                         $namespaceKey = 'image';
4451                 }
4452                 return $prepend . $namespaceKey;
4453         }
4454
4455         /**
4456          * Get all extant redirects to this Title
4457          *
4458          * @param int|null $ns Single namespace to consider; null to consider all namespaces
4459          * @return Title[] Array of Title redirects to this title
4460          */
4461         public function getRedirectsHere( $ns = null ) {
4462                 $redirs = [];
4463
4464                 $dbr = wfGetDB( DB_SLAVE );
4465                 $where = [
4466                         'rd_namespace' => $this->getNamespace(),
4467                         'rd_title' => $this->getDBkey(),
4468                         'rd_from = page_id'
4469                 ];
4470                 if ( $this->isExternal() ) {
4471                         $where['rd_interwiki'] = $this->getInterwiki();
4472                 } else {
4473                         $where[] = 'rd_interwiki = ' . $dbr->addQuotes( '' ) . ' OR rd_interwiki IS NULL';
4474                 }
4475                 if ( !is_null( $ns ) ) {
4476                         $where['page_namespace'] = $ns;
4477                 }
4478
4479                 $res = $dbr->select(
4480                         [ 'redirect', 'page' ],
4481                         [ 'page_namespace', 'page_title' ],
4482                         $where,
4483                         __METHOD__
4484                 );
4485
4486                 foreach ( $res as $row ) {
4487                         $redirs[] = self::newFromRow( $row );
4488                 }
4489                 return $redirs;
4490         }
4491
4492         /**
4493          * Check if this Title is a valid redirect target
4494          *
4495          * @return bool
4496          */
4497         public function isValidRedirectTarget() {
4498                 global $wgInvalidRedirectTargets;
4499
4500                 if ( $this->isSpecialPage() ) {
4501                         // invalid redirect targets are stored in a global array, but explicitly disallow Userlogout here
4502                         if ( $this->isSpecial( 'Userlogout' ) ) {
4503                                 return false;
4504                         }
4505
4506                         foreach ( $wgInvalidRedirectTargets as $target ) {
4507                                 if ( $this->isSpecial( $target ) ) {
4508                                         return false;
4509                                 }
4510                         }
4511                 }
4512
4513                 return true;
4514         }
4515
4516         /**
4517          * Get a backlink cache object
4518          *
4519          * @return BacklinkCache
4520          */
4521         public function getBacklinkCache() {
4522                 return BacklinkCache::get( $this );
4523         }
4524
4525         /**
4526          * Whether the magic words __INDEX__ and __NOINDEX__ function for  this page.
4527          *
4528          * @return bool
4529          */
4530         public function canUseNoindex() {
4531                 global $wgContentNamespaces, $wgExemptFromUserRobotsControl;
4532
4533                 $bannedNamespaces = is_null( $wgExemptFromUserRobotsControl )
4534                         ? $wgContentNamespaces
4535                         : $wgExemptFromUserRobotsControl;
4536
4537                 return !in_array( $this->mNamespace, $bannedNamespaces );
4538
4539         }
4540
4541         /**
4542          * Returns the raw sort key to be used for categories, with the specified
4543          * prefix.  This will be fed to Collation::getSortKey() to get a
4544          * binary sortkey that can be used for actual sorting.
4545          *
4546          * @param string $prefix The prefix to be used, specified using
4547          *   {{defaultsort:}} or like [[Category:Foo|prefix]].  Empty for no
4548          *   prefix.
4549          * @return string
4550          */
4551         public function getCategorySortkey( $prefix = '' ) {
4552                 $unprefixed = $this->getText();
4553
4554                 // Anything that uses this hook should only depend
4555                 // on the Title object passed in, and should probably
4556                 // tell the users to run updateCollations.php --force
4557                 // in order to re-sort existing category relations.
4558                 Hooks::run( 'GetDefaultSortkey', [ $this, &$unprefixed ] );
4559                 if ( $prefix !== '' ) {
4560                         # Separate with a line feed, so the unprefixed part is only used as
4561                         # a tiebreaker when two pages have the exact same prefix.
4562                         # In UCA, tab is the only character that can sort above LF
4563                         # so we strip both of them from the original prefix.
4564                         $prefix = strtr( $prefix, "\n\t", '  ' );
4565                         return "$prefix\n$unprefixed";
4566                 }
4567                 return $unprefixed;
4568         }
4569
4570         /**
4571          * Returns the page language code saved in the database, if $wgPageLanguageUseDB is set
4572          * to true in LocalSettings.php, otherwise returns false. If there is no language saved in
4573          * the db, it will return NULL.
4574          *
4575          * @return string|null|bool
4576          */
4577         private function getDbPageLanguageCode() {
4578                 global $wgPageLanguageUseDB;
4579
4580                 // check, if the page language could be saved in the database, and if so and
4581                 // the value is not requested already, lookup the page language using LinkCache
4582                 if ( $wgPageLanguageUseDB && $this->mDbPageLanguage === false ) {
4583                         $linkCache = LinkCache::singleton();
4584                         $linkCache->addLinkObj( $this );
4585                         $this->mDbPageLanguage = $linkCache->getGoodLinkFieldObj( $this, 'lang' );
4586                 }
4587
4588                 return $this->mDbPageLanguage;
4589         }
4590
4591         /**
4592          * Get the language in which the content of this page is written in
4593          * wikitext. Defaults to $wgContLang, but in certain cases it can be
4594          * e.g. $wgLang (such as special pages, which are in the user language).
4595          *
4596          * @since 1.18
4597          * @return Language
4598          */
4599         public function getPageLanguage() {
4600                 global $wgLang, $wgLanguageCode;
4601                 if ( $this->isSpecialPage() ) {
4602                         // special pages are in the user language
4603                         return $wgLang;
4604                 }
4605
4606                 // Checking if DB language is set
4607                 $dbPageLanguage = $this->getDbPageLanguageCode();
4608                 if ( $dbPageLanguage ) {
4609                         return wfGetLangObj( $dbPageLanguage );
4610                 }
4611
4612                 if ( !$this->mPageLanguage || $this->mPageLanguage[1] !== $wgLanguageCode ) {
4613                         // Note that this may depend on user settings, so the cache should
4614                         // be only per-request.
4615                         // NOTE: ContentHandler::getPageLanguage() may need to load the
4616                         // content to determine the page language!
4617                         // Checking $wgLanguageCode hasn't changed for the benefit of unit
4618                         // tests.
4619                         $contentHandler = ContentHandler::getForTitle( $this );
4620                         $langObj = $contentHandler->getPageLanguage( $this );
4621                         $this->mPageLanguage = [ $langObj->getCode(), $wgLanguageCode ];
4622                 } else {
4623                         $langObj = wfGetLangObj( $this->mPageLanguage[0] );
4624                 }
4625
4626                 return $langObj;
4627         }
4628
4629         /**
4630          * Get the language in which the content of this page is written when
4631          * viewed by user. Defaults to $wgContLang, but in certain cases it can be
4632          * e.g. $wgLang (such as special pages, which are in the user language).
4633          *
4634          * @since 1.20
4635          * @return Language
4636          */
4637         public function getPageViewLanguage() {
4638                 global $wgLang;
4639
4640                 if ( $this->isSpecialPage() ) {
4641                         // If the user chooses a variant, the content is actually
4642                         // in a language whose code is the variant code.
4643                         $variant = $wgLang->getPreferredVariant();
4644                         if ( $wgLang->getCode() !== $variant ) {
4645                                 return Language::factory( $variant );
4646                         }
4647
4648                         return $wgLang;
4649                 }
4650
4651                 // Checking if DB language is set
4652                 $dbPageLanguage = $this->getDbPageLanguageCode();
4653                 if ( $dbPageLanguage ) {
4654                         $pageLang = wfGetLangObj( $dbPageLanguage );
4655                         $variant = $pageLang->getPreferredVariant();
4656                         if ( $pageLang->getCode() !== $variant ) {
4657                                 $pageLang = Language::factory( $variant );
4658                         }
4659
4660                         return $pageLang;
4661                 }
4662
4663                 // @note Can't be cached persistently, depends on user settings.
4664                 // @note ContentHandler::getPageViewLanguage() may need to load the
4665                 //   content to determine the page language!
4666                 $contentHandler = ContentHandler::getForTitle( $this );
4667                 $pageLang = $contentHandler->getPageViewLanguage( $this );
4668                 return $pageLang;
4669         }
4670
4671         /**
4672          * Get a list of rendered edit notices for this page.
4673          *
4674          * Array is keyed by the original message key, and values are rendered using parseAsBlock, so
4675          * they will already be wrapped in paragraphs.
4676          *
4677          * @since 1.21
4678          * @param int $oldid Revision ID that's being edited
4679          * @return array
4680          */
4681         public function getEditNotices( $oldid = 0 ) {
4682                 $notices = [];
4683
4684                 // Optional notice for the entire namespace
4685                 $editnotice_ns = 'editnotice-' . $this->getNamespace();
4686                 $msg = wfMessage( $editnotice_ns );
4687                 if ( $msg->exists() ) {
4688                         $html = $msg->parseAsBlock();
4689                         // Edit notices may have complex logic, but output nothing (T91715)
4690                         if ( trim( $html ) !== '' ) {
4691                                 $notices[$editnotice_ns] = Html::rawElement(
4692                                         'div',
4693                                         [ 'class' => [
4694                                                 'mw-editnotice',
4695                                                 'mw-editnotice-namespace',
4696                                                 Sanitizer::escapeClass( "mw-$editnotice_ns" )
4697                                         ] ],
4698                                         $html
4699                                 );
4700                         }
4701                 }
4702
4703                 if ( MWNamespace::hasSubpages( $this->getNamespace() ) ) {
4704                         // Optional notice for page itself and any parent page
4705                         $parts = explode( '/', $this->getDBkey() );
4706                         $editnotice_base = $editnotice_ns;
4707                         while ( count( $parts ) > 0 ) {
4708                                 $editnotice_base .= '-' . array_shift( $parts );
4709                                 $msg = wfMessage( $editnotice_base );
4710                                 if ( $msg->exists() ) {
4711                                         $html = $msg->parseAsBlock();
4712                                         if ( trim( $html ) !== '' ) {
4713                                                 $notices[$editnotice_base] = Html::rawElement(
4714                                                         'div',
4715                                                         [ 'class' => [
4716                                                                 'mw-editnotice',
4717                                                                 'mw-editnotice-base',
4718                                                                 Sanitizer::escapeClass( "mw-$editnotice_base" )
4719                                                         ] ],
4720                                                         $html
4721                                                 );
4722                                         }
4723                                 }
4724                         }
4725                 } else {
4726                         // Even if there are no subpages in namespace, we still don't want "/" in MediaWiki message keys
4727                         $editnoticeText = $editnotice_ns . '-' . strtr( $this->getDBkey(), '/', '-' );
4728                         $msg = wfMessage( $editnoticeText );
4729                         if ( $msg->exists() ) {
4730                                 $html = $msg->parseAsBlock();
4731                                 if ( trim( $html ) !== '' ) {
4732                                         $notices[$editnoticeText] = Html::rawElement(
4733                                                 'div',
4734                                                 [ 'class' => [
4735                                                         'mw-editnotice',
4736                                                         'mw-editnotice-page',
4737                                                         Sanitizer::escapeClass( "mw-$editnoticeText" )
4738                                                 ] ],
4739                                                 $html
4740                                         );
4741                                 }
4742                         }
4743                 }
4744
4745                 Hooks::run( 'TitleGetEditNotices', [ $this, $oldid, &$notices ] );
4746                 return $notices;
4747         }
4748
4749         /**
4750          * @return array
4751          */
4752         public function __sleep() {
4753                 return [
4754                         'mNamespace',
4755                         'mDbkeyform',
4756                         'mFragment',
4757                         'mInterwiki',
4758                         'mLocalInterwiki',
4759                         'mUserCaseDBKey',
4760                         'mDefaultNamespace',
4761                 ];
4762         }
4763
4764         public function __wakeup() {
4765                 $this->mArticleID = ( $this->mNamespace >= 0 ) ? -1 : 0;
4766                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
4767                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
4768         }
4769
4770 }