includes/Title.php

   1 <?php
   2 /**
   3  * Representation of a title within %MediaWiki.
   4  *
   5  * See title.txt
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License along
  18  * with this program; if not, write to the Free Software Foundation, Inc.,
  19  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  20  * http://www.gnu.org/copyleft/gpl.html
  21  *
  22  * @file
  23  */
  24
  25 use Wikimedia\Rdbms\Database;
  26 use Wikimedia\Rdbms\IDatabase;
  27 use MediaWiki\Linker\LinkTarget;
  28 use MediaWiki\Interwiki\InterwikiLookup;
  29 use MediaWiki\MediaWikiServices;
  30
  31 /**
  32  * Represents a title within MediaWiki.
  33  * Optionally may contain an interwiki designation or namespace.
  34  * @note This class can fetch various kinds of data from the database;
  35  *       however, it does so inefficiently.
  36  * @note Consider using a TitleValue object instead. TitleValue is more lightweight
  37  *       and does not rely on global state or the database.
  38  */
  39 class Title implements LinkTarget {
  40         /** @var HashBagOStuff */
  41         static private $titleCache = null;
  42
  43         /**
  44          * Title::newFromText maintains a cache to avoid expensive re-normalization of
  45          * commonly used titles. On a batch operation this can become a memory leak
  46          * if not bounded. After hitting this many titles reset the cache.
  47          */
  48         const CACHE_MAX = 1000;
  49
  50         /**
  51          * Used to be GAID_FOR_UPDATE define. Used with getArticleID() and friends
  52          * to use the master DB
  53          */
  54         const GAID_FOR_UPDATE = 1;
  55
  56         /**
  57          * @name Private member variables
  58          * Please use the accessor functions instead.
  59          * @private
  60          */
  61         // @{
  62
  63         /** @var string Text form (spaces not underscores) of the main part */
  64         public $mTextform = '';
  65
  66         /** @var string URL-encoded form of the main part */
  67         public $mUrlform = '';
  68
  69         /** @var string Main part with underscores */
  70         public $mDbkeyform = '';
  71
  72         /** @var string Database key with the initial letter in the case specified by the user */
  73         protected $mUserCaseDBKey;
  74
  75         /** @var int Namespace index, i.e. one of the NS_xxxx constants */
  76         public $mNamespace = NS_MAIN;
  77
  78         /** @var string Interwiki prefix */
  79         public $mInterwiki = '';
  80
  81         /** @var bool Was this Title created from a string with a local interwiki prefix? */
  82         private $mLocalInterwiki = false;
  83
  84         /** @var string Title fragment (i.e. the bit after the #) */
  85         public $mFragment = '';
  86
  87         /** @var int Article ID, fetched from the link cache on demand */
  88         public $mArticleID = -1;
  89
  90         /** @var bool|int ID of most recent revision */
  91         protected $mLatestID = false;
  92
  93         /**
  94          * @var bool|string ID of the page's content model, i.e. one of the
  95          *   CONTENT_MODEL_XXX constants
  96          */
  97         private $mContentModel = false;
  98
  99         /**
 100          * @var bool If a content model was forced via setContentModel()
 101          *   this will be true to avoid having other code paths reset it
 102          */
 103         private $mForcedContentModel = false;
 104
 105         /** @var int Estimated number of revisions; null of not loaded */
 106         private $mEstimateRevisions;
 107
 108         /** @var array Array of groups allowed to edit this article */
 109         public $mRestrictions = [];
 110
 111         /** @var string|bool */
 112         protected $mOldRestrictions = false;
 113
 114         /** @var bool Cascade restrictions on this page to included templates and images? */
 115         public $mCascadeRestriction;
 116
 117         /** Caching the results of getCascadeProtectionSources */
 118         public $mCascadingRestrictions;
 119
 120         /** @var array When do the restrictions on this page expire? */
 121         protected $mRestrictionsExpiry = [];
 122
 123         /** @var bool Are cascading restrictions in effect on this page? */
 124         protected $mHasCascadingRestrictions;
 125
 126         /** @var array Where are the cascading restrictions coming from on this page? */
 127         public $mCascadeSources;
 128
 129         /** @var bool Boolean for initialisation on demand */
 130         public $mRestrictionsLoaded = false;
 131
 132         /** @var string Text form including namespace/interwiki, initialised on demand */
 133         protected $mPrefixedText = null;
 134
 135         /** @var mixed Cached value for getTitleProtection (create protection) */
 136         public $mTitleProtection;
 137
 138         /**
 139          * @var int Namespace index when there is no namespace. Don't change the
 140          *   following default, NS_MAIN is hardcoded in several places. See T2696.
 141          *   Zero except in {{transclusion}} tags.
 142          */
 143         public $mDefaultNamespace = NS_MAIN;
 144
 145         /** @var int The page length, 0 for special pages */
 146         protected $mLength = -1;
 147
 148         /** @var null Is the article at this title a redirect? */
 149         public $mRedirect = null;
 150
 151         /** @var array Associative array of user ID -> timestamp/false */
 152         private $mNotificationTimestamp = [];
 153
 154         /** @var bool Whether a page has any subpages */
 155         private $mHasSubpages;
 156
 157         /** @var bool The (string) language code of the page's language and content code. */
 158         private $mPageLanguage = false;
 159
 160         /** @var string|bool|null The page language code from the database, null if not saved in
 161          * the database or false if not loaded, yet. */
 162         private $mDbPageLanguage = false;
 163
 164         /** @var TitleValue A corresponding TitleValue object */
 165         private $mTitleValue = null;
 166
 167         /** @var bool Would deleting this page be a big deletion? */
 168         private $mIsBigDeletion = null;
 169         // @}
 170
 171         /**
 172          * B/C kludge: provide a TitleParser for use by Title.
 173          * Ideally, Title would have no methods that need this.
 174          * Avoid usage of this singleton by using TitleValue
 175          * and the associated services when possible.
 176          *
 177          * @return TitleFormatter
 178          */
 179         private static function getTitleFormatter() {
 180                 return MediaWikiServices::getInstance()->getTitleFormatter();
 181         }
 182
 183         /**
 184          * B/C kludge: provide an InterwikiLookup for use by Title.
 185          * Ideally, Title would have no methods that need this.
 186          * Avoid usage of this singleton by using TitleValue
 187          * and the associated services when possible.
 188          *
 189          * @return InterwikiLookup
 190          */
 191         private static function getInterwikiLookup() {
 192                 return MediaWikiServices::getInstance()->getInterwikiLookup();
 193         }
 194
 195         /**
 196          * @access protected
 197          */
 198         function __construct() {
 199         }
 200
 201         /**
 202          * Create a new Title from a prefixed DB key
 203          *
 204          * @param string $key The database key, which has underscores
 205          *      instead of spaces, possibly including namespace and
 206          *      interwiki prefixes
 207          * @return Title|null Title, or null on an error
 208          */
 209         public static function newFromDBkey( $key ) {
 210                 $t = new Title();
 211                 $t->mDbkeyform = $key;
 212
 213                 try {
 214                         $t->secureAndSplit();
 215                         return $t;
 216                 } catch ( MalformedTitleException $ex ) {
 217                         return null;
 218                 }
 219         }
 220
 221         /**
 222          * Create a new Title from a TitleValue
 223          *
 224          * @param TitleValue $titleValue Assumed to be safe.
 225          *
 226          * @return Title
 227          */
 228         public static function newFromTitleValue( TitleValue $titleValue ) {
 229                 return self::newFromLinkTarget( $titleValue );
 230         }
 231
 232         /**
 233          * Create a new Title from a LinkTarget
 234          *
 235          * @param LinkTarget $linkTarget Assumed to be safe.
 236          *
 237          * @return Title
 238          */
 239         public static function newFromLinkTarget( LinkTarget $linkTarget ) {
 240                 if ( $linkTarget instanceof Title ) {
 241                         // Special case if it's already a Title object
 242                         return $linkTarget;
 243                 }
 244                 return self::makeTitle(
 245                         $linkTarget->getNamespace(),
 246                         $linkTarget->getText(),
 247                         $linkTarget->getFragment(),
 248                         $linkTarget->getInterwiki()
 249                 );
 250         }
 251
 252         /**
 253          * Create a new Title from text, such as what one would find in a link. De-
 254          * codes any HTML entities in the text.
 255          *
 256          * @param string|int|null $text The link text; spaces, prefixes, and an
 257          *   initial ':' indicating the main namespace are accepted.
 258          * @param int $defaultNamespace The namespace to use if none is specified
 259          *   by a prefix.  If you want to force a specific namespace even if
 260          *   $text might begin with a namespace prefix, use makeTitle() or
 261          *   makeTitleSafe().
 262          * @throws InvalidArgumentException
 263          * @return Title|null Title or null on an error.
 264          */
 265         public static function newFromText( $text, $defaultNamespace = NS_MAIN ) {
 266                 // DWIM: Integers can be passed in here when page titles are used as array keys.
 267                 if ( $text !== null && !is_string( $text ) && !is_int( $text ) ) {
 268                         throw new InvalidArgumentException( '$text must be a string.' );
 269                 }
 270                 if ( $text === null ) {
 271                         return null;
 272                 }
 273
 274                 try {
 275                         return self::newFromTextThrow( strval( $text ), $defaultNamespace );
 276                 } catch ( MalformedTitleException $ex ) {
 277                         return null;
 278                 }
 279         }
 280
 281         /**
 282          * Like Title::newFromText(), but throws MalformedTitleException when the title is invalid,
 283          * rather than returning null.
 284          *
 285          * The exception subclasses encode detailed information about why the title is invalid.
 286          *
 287          * @see Title::newFromText
 288          *
 289          * @since 1.25
 290          * @param string $text Title text to check
 291          * @param int $defaultNamespace
 292          * @throws MalformedTitleException If the title is invalid
 293          * @return Title
 294          */
 295         public static function newFromTextThrow( $text, $defaultNamespace = NS_MAIN ) {
 296                 if ( is_object( $text ) ) {
 297                         throw new MWException( '$text must be a string, given an object' );
 298                 }
 299
 300                 $titleCache = self::getTitleCache();
 301
 302                 // Wiki pages often contain multiple links to the same page.
 303                 // Title normalization and parsing can become expensive on pages with many
 304                 // links, so we can save a little time by caching them.
 305                 // In theory these are value objects and won't get changed...
 306                 if ( $defaultNamespace == NS_MAIN ) {
 307                         $t = $titleCache->get( $text );
 308                         if ( $t ) {
 309                                 return $t;
 310                         }
 311                 }
 312
 313                 // Convert things like &eacute; &#257; or &#x3017; into normalized (T16952) text
 314                 $filteredText = Sanitizer::decodeCharReferencesAndNormalize( $text );
 315
 316                 $t = new Title();
 317                 $t->mDbkeyform = strtr( $filteredText, ' ', '_' );
 318                 $t->mDefaultNamespace = intval( $defaultNamespace );
 319
 320                 $t->secureAndSplit();
 321                 if ( $defaultNamespace == NS_MAIN ) {
 322                         $titleCache->set( $text, $t );
 323                 }
 324                 return $t;
 325         }
 326
 327         /**
 328          * THIS IS NOT THE FUNCTION YOU WANT. Use Title::newFromText().
 329          *
 330          * Example of wrong and broken code:
 331          * $title = Title::newFromURL( $wgRequest->getVal( 'title' ) );
 332          *
 333          * Example of right code:
 334          * $title = Title::newFromText( $wgRequest->getVal( 'title' ) );
 335          *
 336          * Create a new Title from URL-encoded text. Ensures that
 337          * the given title's length does not exceed the maximum.
 338          *
 339          * @param string $url The title, as might be taken from a URL
 340          * @return Title|null The new object, or null on an error
 341          */
 342         public static function newFromURL( $url ) {
 343                 $t = new Title();
 344
 345                 # For compatibility with old buggy URLs. "+" is usually not valid in titles,
 346                 # but some URLs used it as a space replacement and they still come
 347                 # from some external search tools.
 348                 if ( strpos( self::legalChars(), '+' ) === false ) {
 349                         $url = strtr( $url, '+', ' ' );
 350                 }
 351
 352                 $t->mDbkeyform = strtr( $url, ' ', '_' );
 353
 354                 try {
 355                         $t->secureAndSplit();
 356                         return $t;
 357                 } catch ( MalformedTitleException $ex ) {
 358                         return null;
 359                 }
 360         }
 361
 362         /**
 363          * @return HashBagOStuff
 364          */
 365         private static function getTitleCache() {
 366                 if ( self::$titleCache == null ) {
 367                         self::$titleCache = new HashBagOStuff( [ 'maxKeys' => self::CACHE_MAX ] );
 368                 }
 369                 return self::$titleCache;
 370         }
 371
 372         /**
 373          * Returns a list of fields that are to be selected for initializing Title
 374          * objects or LinkCache entries. Uses $wgContentHandlerUseDB to determine
 375          * whether to include page_content_model.
 376          *
 377          * @return array
 378          */
 379         protected static function getSelectFields() {
 380                 global $wgContentHandlerUseDB, $wgPageLanguageUseDB;
 381
 382                 $fields = [
 383                         'page_namespace', 'page_title', 'page_id',
 384                         'page_len', 'page_is_redirect', 'page_latest',
 385                 ];
 386
 387                 if ( $wgContentHandlerUseDB ) {
 388                         $fields[] = 'page_content_model';
 389                 }
 390
 391                 if ( $wgPageLanguageUseDB ) {
 392                         $fields[] = 'page_lang';
 393                 }
 394
 395                 return $fields;
 396         }
 397
 398         /**
 399          * Create a new Title from an article ID
 400          *
 401          * @param int $id The page_id corresponding to the Title to create
 402          * @param int $flags Use Title::GAID_FOR_UPDATE to use master
 403          * @return Title|null The new object, or null on an error
 404          */
 405         public static function newFromID( $id, $flags = 0 ) {
 406                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_REPLICA );
 407                 $row = $db->selectRow(
 408                         'page',
 409                         self::getSelectFields(),
 410                         [ 'page_id' => $id ],
 411                         __METHOD__
 412                 );
 413                 if ( $row !== false ) {
 414                         $title = self::newFromRow( $row );
 415                 } else {
 416                         $title = null;
 417                 }
 418                 return $title;
 419         }
 420
 421         /**
 422          * Make an array of titles from an array of IDs
 423          *
 424          * @param int[] $ids Array of IDs
 425          * @return Title[] Array of Titles
 426          */
 427         public static function newFromIDs( $ids ) {
 428                 if ( !count( $ids ) ) {
 429                         return [];
 430                 }
 431                 $dbr = wfGetDB( DB_REPLICA );
 432
 433                 $res = $dbr->select(
 434                         'page',
 435                         self::getSelectFields(),
 436                         [ 'page_id' => $ids ],
 437                         __METHOD__
 438                 );
 439
 440                 $titles = [];
 441                 foreach ( $res as $row ) {
 442                         $titles[] = self::newFromRow( $row );
 443                 }
 444                 return $titles;
 445         }
 446
 447         /**
 448          * Make a Title object from a DB row
 449          *
 450          * @param stdClass $row Object database row (needs at least page_title,page_namespace)
 451          * @return Title Corresponding Title
 452          */
 453         public static function newFromRow( $row ) {
 454                 $t = self::makeTitle( $row->page_namespace, $row->page_title );
 455                 $t->loadFromRow( $row );
 456                 return $t;
 457         }
 458
 459         /**
 460          * Load Title object fields from a DB row.
 461          * If false is given, the title will be treated as non-existing.
 462          *
 463          * @param stdClass|bool $row Database row
 464          */
 465         public function loadFromRow( $row ) {
 466                 if ( $row ) { // page found
 467                         if ( isset( $row->page_id ) ) {
 468                                 $this->mArticleID = (int)$row->page_id;
 469                         }
 470                         if ( isset( $row->page_len ) ) {
 471                                 $this->mLength = (int)$row->page_len;
 472                         }
 473                         if ( isset( $row->page_is_redirect ) ) {
 474                                 $this->mRedirect = (bool)$row->page_is_redirect;
 475                         }
 476                         if ( isset( $row->page_latest ) ) {
 477                                 $this->mLatestID = (int)$row->page_latest;
 478                         }
 479                         if ( !$this->mForcedContentModel && isset( $row->page_content_model ) ) {
 480                                 $this->mContentModel = strval( $row->page_content_model );
 481                         } elseif ( !$this->mForcedContentModel ) {
 482                                 $this->mContentModel = false; # initialized lazily in getContentModel()
 483                         }
 484                         if ( isset( $row->page_lang ) ) {
 485                                 $this->mDbPageLanguage = (string)$row->page_lang;
 486                         }
 487                         if ( isset( $row->page_restrictions ) ) {
 488                                 $this->mOldRestrictions = $row->page_restrictions;
 489                         }
 490                 } else { // page not found
 491                         $this->mArticleID = 0;
 492                         $this->mLength = 0;
 493                         $this->mRedirect = false;
 494                         $this->mLatestID = 0;
 495                         if ( !$this->mForcedContentModel ) {
 496                                 $this->mContentModel = false; # initialized lazily in getContentModel()
 497                         }
 498                 }
 499         }
 500
 501         /**
 502          * Create a new Title from a namespace index and a DB key.
 503          * It's assumed that $ns and $title are *valid*, for instance when
 504          * they came directly from the database or a special page name.
 505          * For convenience, spaces are converted to underscores so that
 506          * eg user_text fields can be used directly.
 507          *
 508          * @param int $ns The namespace of the article
 509          * @param string $title The unprefixed database key form
 510          * @param string $fragment The link fragment (after the "#")
 511          * @param string $interwiki The interwiki prefix
 512          * @return Title The new object
 513          */
 514         public static function makeTitle( $ns, $title, $fragment = '', $interwiki = '' ) {
 515                 $t = new Title();
 516                 $t->mInterwiki = $interwiki;
 517                 $t->mFragment = $fragment;
 518                 $t->mNamespace = $ns = intval( $ns );
 519                 $t->mDbkeyform = strtr( $title, ' ', '_' );
 520                 $t->mArticleID = ( $ns >= 0 ) ? -1 : 0;
 521                 $t->mUrlform = wfUrlencode( $t->mDbkeyform );
 522                 $t->mTextform = strtr( $title, '_', ' ' );
 523                 $t->mContentModel = false; # initialized lazily in getContentModel()
 524                 return $t;
 525         }
 526
 527         /**
 528          * Create a new Title from a namespace index and a DB key.
 529          * The parameters will be checked for validity, which is a bit slower
 530          * than makeTitle() but safer for user-provided data.
 531          *
 532          * @param int $ns The namespace of the article
 533          * @param string $title Database key form
 534          * @param string $fragment The link fragment (after the "#")
 535          * @param string $interwiki Interwiki prefix
 536          * @return Title|null The new object, or null on an error
 537          */
 538         public static function makeTitleSafe( $ns, $title, $fragment = '', $interwiki = '' ) {
 539                 if ( !MWNamespace::exists( $ns ) ) {
 540                         return null;
 541                 }
 542
 543                 $t = new Title();
 544                 $t->mDbkeyform = self::makeName( $ns, $title, $fragment, $interwiki, true );
 545
 546                 try {
 547                         $t->secureAndSplit();
 548                         return $t;
 549                 } catch ( MalformedTitleException $ex ) {
 550                         return null;
 551                 }
 552         }
 553
 554         /**
 555          * Create a new Title for the Main Page
 556          *
 557          * @return Title The new object
 558          */
 559         public static function newMainPage() {
 560                 $title = self::newFromText( wfMessage( 'mainpage' )->inContentLanguage()->text() );
 561                 // Don't give fatal errors if the message is broken
 562                 if ( !$title ) {
 563                         $title = self::newFromText( 'Main Page' );
 564                 }
 565                 return $title;
 566         }
 567
 568         /**
 569          * Get the prefixed DB key associated with an ID
 570          *
 571          * @param int $id The page_id of the article
 572          * @return Title|null An object representing the article, or null if no such article was found
 573          */
 574         public static function nameOf( $id ) {
 575                 $dbr = wfGetDB( DB_REPLICA );
 576
 577                 $s = $dbr->selectRow(
 578                         'page',
 579                         [ 'page_namespace', 'page_title' ],
 580                         [ 'page_id' => $id ],
 581                         __METHOD__
 582                 );
 583                 if ( $s === false ) {
 584                         return null;
 585                 }
 586
 587                 $n = self::makeName( $s->page_namespace, $s->page_title );
 588                 return $n;
 589         }
 590
 591         /**
 592          * Get a regex character class describing the legal characters in a link
 593          *
 594          * @return string The list of characters, not delimited
 595          */
 596         public static function legalChars() {
 597                 global $wgLegalTitleChars;
 598                 return $wgLegalTitleChars;
 599         }
 600
 601         /**
 602          * Returns a simple regex that will match on characters and sequences invalid in titles.
 603          * Note that this doesn't pick up many things that could be wrong with titles, but that
 604          * replacing this regex with something valid will make many titles valid.
 605          *
 606          * @deprecated since 1.25, use MediaWikiTitleCodec::getTitleInvalidRegex() instead
 607          *
 608          * @return string Regex string
 609          */
 610         static function getTitleInvalidRegex() {
 611                 wfDeprecated( __METHOD__, '1.25' );
 612                 return MediaWikiTitleCodec::getTitleInvalidRegex();
 613         }
 614
 615         /**
 616          * Utility method for converting a character sequence from bytes to Unicode.
 617          *
 618          * Primary usecase being converting $wgLegalTitleChars to a sequence usable in
 619          * javascript, as PHP uses UTF-8 bytes where javascript uses Unicode code units.
 620          *
 621          * @param string $byteClass
 622          * @return string
 623          */
 624         public static function convertByteClassToUnicodeClass( $byteClass ) {
 625                 $length = strlen( $byteClass );
 626                 // Input token queue
 627                 $x0 = $x1 = $x2 = '';
 628                 // Decoded queue
 629                 $d0 = $d1 = $d2 = '';
 630                 // Decoded integer codepoints
 631                 $ord0 = $ord1 = $ord2 = 0;
 632                 // Re-encoded queue
 633                 $r0 = $r1 = $r2 = '';
 634                 // Output
 635                 $out = '';
 636                 // Flags
 637                 $allowUnicode = false;
 638                 for ( $pos = 0; $pos < $length; $pos++ ) {
 639                         // Shift the queues down
 640                         $x2 = $x1;
 641                         $x1 = $x0;
 642                         $d2 = $d1;
 643                         $d1 = $d0;
 644                         $ord2 = $ord1;
 645                         $ord1 = $ord0;
 646                         $r2 = $r1;
 647                         $r1 = $r0;
 648                         // Load the current input token and decoded values
 649                         $inChar = $byteClass[$pos];
 650                         if ( $inChar == '\\' ) {
 651                                 if ( preg_match( '/x([0-9a-fA-F]{2})/A', $byteClass, $m, 0, $pos + 1 ) ) {
 652                                         $x0 = $inChar . $m[0];
 653                                         $d0 = chr( hexdec( $m[1] ) );
 654                                         $pos += strlen( $m[0] );
 655                                 } elseif ( preg_match( '/[0-7]{3}/A', $byteClass, $m, 0, $pos + 1 ) ) {
 656                                         $x0 = $inChar . $m[0];
 657                                         $d0 = chr( octdec( $m[0] ) );
 658                                         $pos += strlen( $m[0] );
 659                                 } elseif ( $pos + 1 >= $length ) {
 660                                         $x0 = $d0 = '\\';
 661                                 } else {
 662                                         $d0 = $byteClass[$pos + 1];
 663                                         $x0 = $inChar . $d0;
 664                                         $pos += 1;
 665                                 }
 666                         } else {
 667                                 $x0 = $d0 = $inChar;
 668                         }
 669                         $ord0 = ord( $d0 );
 670                         // Load the current re-encoded value
 671                         if ( $ord0 < 32 || $ord0 == 0x7f ) {
 672                                 $r0 = sprintf( '\x%02x', $ord0 );
 673                         } elseif ( $ord0 >= 0x80 ) {
 674                                 // Allow unicode if a single high-bit character appears
 675                                 $r0 = sprintf( '\x%02x', $ord0 );
 676                                 $allowUnicode = true;
 677                         } elseif ( strpos( '-\\[]^', $d0 ) !== false ) {
 678                                 $r0 = '\\' . $d0;
 679                         } else {
 680                                 $r0 = $d0;
 681                         }
 682                         // Do the output
 683                         if ( $x0 !== '' && $x1 === '-' && $x2 !== '' ) {
 684                                 // Range
 685                                 if ( $ord2 > $ord0 ) {
 686                                         // Empty range
 687                                 } elseif ( $ord0 >= 0x80 ) {
 688                                         // Unicode range
 689                                         $allowUnicode = true;
 690                                         if ( $ord2 < 0x80 ) {
 691                                                 // Keep the non-unicode section of the range
 692                                                 $out .= "$r2-\\x7F";
 693                                         }
 694                                 } else {
 695                                         // Normal range
 696                                         $out .= "$r2-$r0";
 697                                 }
 698                                 // Reset state to the initial value
 699                                 $x0 = $x1 = $d0 = $d1 = $r0 = $r1 = '';
 700                         } elseif ( $ord2 < 0x80 ) {
 701                                 // ASCII character
 702                                 $out .= $r2;
 703                         }
 704                 }
 705                 if ( $ord1 < 0x80 ) {
 706                         $out .= $r1;
 707                 }
 708                 if ( $ord0 < 0x80 ) {
 709                         $out .= $r0;
 710                 }
 711                 if ( $allowUnicode ) {
 712                         $out .= '\u0080-\uFFFF';
 713                 }
 714                 return $out;
 715         }
 716
 717         /**
 718          * Make a prefixed DB key from a DB key and a namespace index
 719          *
 720          * @param int $ns Numerical representation of the namespace
 721          * @param string $title The DB key form the title
 722          * @param string $fragment The link fragment (after the "#")
 723          * @param string $interwiki The interwiki prefix
 724          * @param bool $canonicalNamespace If true, use the canonical name for
 725          *   $ns instead of the localized version.
 726          * @return string The prefixed form of the title
 727          */
 728         public static function makeName( $ns, $title, $fragment = '', $interwiki = '',
 729                 $canonicalNamespace = false
 730         ) {
 731                 global $wgContLang;
 732
 733                 if ( $canonicalNamespace ) {
 734                         $namespace = MWNamespace::getCanonicalName( $ns );
 735                 } else {
 736                         $namespace = $wgContLang->getNsText( $ns );
 737                 }
 738                 $name = $namespace == '' ? $title : "$namespace:$title";
 739                 if ( strval( $interwiki ) != '' ) {
 740                         $name = "$interwiki:$name";
 741                 }
 742                 if ( strval( $fragment ) != '' ) {
 743                         $name .= '#' . $fragment;
 744                 }
 745                 return $name;
 746         }
 747
 748         /**
 749          * Escape a text fragment, say from a link, for a URL
 750          *
 751          * @param string $fragment Containing a URL or link fragment (after the "#")
 752          * @return string Escaped string
 753          */
 754         static function escapeFragmentForURL( $fragment ) {
 755                 # Note that we don't urlencode the fragment.  urlencoded Unicode
 756                 # fragments appear not to work in IE (at least up to 7) or in at least
 757                 # one version of Opera 9.x.  The W3C validator, for one, doesn't seem
 758                 # to care if they aren't encoded.
 759                 return Sanitizer::escapeId( $fragment, 'noninitial' );
 760         }
 761
 762         /**
 763          * Callback for usort() to do title sorts by (namespace, title)
 764          *
 765          * @param LinkTarget $a
 766          * @param LinkTarget $b
 767          *
 768          * @return int Result of string comparison, or namespace comparison
 769          */
 770         public static function compare( LinkTarget $a, LinkTarget $b ) {
 771                 if ( $a->getNamespace() == $b->getNamespace() ) {
 772                         return strcmp( $a->getText(), $b->getText() );
 773                 } else {
 774                         return $a->getNamespace() - $b->getNamespace();
 775                 }
 776         }
 777
 778         /**
 779          * Determine whether the object refers to a page within
 780          * this project (either this wiki or a wiki with a local
 781          * interwiki, see https://www.mediawiki.org/wiki/Manual:Interwiki_table#iw_local )
 782          *
 783          * @return bool True if this is an in-project interwiki link or a wikilink, false otherwise
 784          */
 785         public function isLocal() {
 786                 if ( $this->isExternal() ) {
 787                         $iw = self::getInterwikiLookup()->fetch( $this->mInterwiki );
 788                         if ( $iw ) {
 789                                 return $iw->isLocal();
 790                         }
 791                 }
 792                 return true;
 793         }
 794
 795         /**
 796          * Is this Title interwiki?
 797          *
 798          * @return bool
 799          */
 800         public function isExternal() {
 801                 return $this->mInterwiki !== '';
 802         }
 803
 804         /**
 805          * Get the interwiki prefix
 806          *
 807          * Use Title::isExternal to check if a interwiki is set
 808          *
 809          * @return string Interwiki prefix
 810          */
 811         public function getInterwiki() {
 812                 return $this->mInterwiki;
 813         }
 814
 815         /**
 816          * Was this a local interwiki link?
 817          *
 818          * @return bool
 819          */
 820         public function wasLocalInterwiki() {
 821                 return $this->mLocalInterwiki;
 822         }
 823
 824         /**
 825          * Determine whether the object refers to a page within
 826          * this project and is transcludable.
 827          *
 828          * @return bool True if this is transcludable
 829          */
 830         public function isTrans() {
 831                 if ( !$this->isExternal() ) {
 832                         return false;
 833                 }
 834
 835                 return self::getInterwikiLookup()->fetch( $this->mInterwiki )->isTranscludable();
 836         }
 837
 838         /**
 839          * Returns the DB name of the distant wiki which owns the object.
 840          *
 841          * @return string|false The DB name
 842          */
 843         public function getTransWikiID() {
 844                 if ( !$this->isExternal() ) {
 845                         return false;
 846                 }
 847
 848                 return self::getInterwikiLookup()->fetch( $this->mInterwiki )->getWikiID();
 849         }
 850
 851         /**
 852          * Get a TitleValue object representing this Title.
 853          *
 854          * @note Not all valid Titles have a corresponding valid TitleValue
 855          * (e.g. TitleValues cannot represent page-local links that have a
 856          * fragment but no title text).
 857          *
 858          * @return TitleValue|null
 859          */
 860         public function getTitleValue() {
 861                 if ( $this->mTitleValue === null ) {
 862                         try {
 863                                 $this->mTitleValue = new TitleValue(
 864                                         $this->getNamespace(),
 865                                         $this->getDBkey(),
 866                                         $this->getFragment(),
 867                                         $this->getInterwiki()
 868                                 );
 869                         } catch ( InvalidArgumentException $ex ) {
 870                                 wfDebug( __METHOD__ . ': Can\'t create a TitleValue for [[' .
 871                                         $this->getPrefixedText() . ']]: ' . $ex->getMessage() . "\n" );
 872                         }
 873                 }
 874
 875                 return $this->mTitleValue;
 876         }
 877
 878         /**
 879          * Get the text form (spaces not underscores) of the main part
 880          *
 881          * @return string Main part of the title
 882          */
 883         public function getText() {
 884                 return $this->mTextform;
 885         }
 886
 887         /**
 888          * Get the URL-encoded form of the main part
 889          *
 890          * @return string Main part of the title, URL-encoded
 891          */
 892         public function getPartialURL() {
 893                 return $this->mUrlform;
 894         }
 895
 896         /**
 897          * Get the main part with underscores
 898          *
 899          * @return string Main part of the title, with underscores
 900          */
 901         public function getDBkey() {
 902                 return $this->mDbkeyform;
 903         }
 904
 905         /**
 906          * Get the DB key with the initial letter case as specified by the user
 907          *
 908          * @return string DB key
 909          */
 910         function getUserCaseDBKey() {
 911                 if ( !is_null( $this->mUserCaseDBKey ) ) {
 912                         return $this->mUserCaseDBKey;
 913                 } else {
 914                         // If created via makeTitle(), $this->mUserCaseDBKey is not set.
 915                         return $this->mDbkeyform;
 916                 }
 917         }
 918
 919         /**
 920          * Get the namespace index, i.e. one of the NS_xxxx constants.
 921          *
 922          * @return int Namespace index
 923          */
 924         public function getNamespace() {
 925                 return $this->mNamespace;
 926         }
 927
 928         /**
 929          * Get the page's content model id, see the CONTENT_MODEL_XXX constants.
 930          *
 931          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
 932          * @return string Content model id
 933          */
 934         public function getContentModel( $flags = 0 ) {
 935                 if ( !$this->mForcedContentModel
 936                         && ( !$this->mContentModel || $flags === self::GAID_FOR_UPDATE )
 937                         && $this->getArticleID( $flags )
 938                 ) {
 939                         $linkCache = LinkCache::singleton();
 940                         $linkCache->addLinkObj( $this ); # in case we already had an article ID
 941                         $this->mContentModel = $linkCache->getGoodLinkFieldObj( $this, 'model' );
 942                 }
 943
 944                 if ( !$this->mContentModel ) {
 945                         $this->mContentModel = ContentHandler::getDefaultModelFor( $this );
 946                 }
 947
 948                 return $this->mContentModel;
 949         }
 950
 951         /**
 952          * Convenience method for checking a title's content model name
 953          *
 954          * @param string $id The content model ID (use the CONTENT_MODEL_XXX constants).
 955          * @return bool True if $this->getContentModel() == $id
 956          */
 957         public function hasContentModel( $id ) {
 958                 return $this->getContentModel() == $id;
 959         }
 960
 961         /**
 962          * Set a proposed content model for the page for permissions
 963          * checking. This does not actually change the content model
 964          * of a title!
 965          *
 966          * Additionally, you should make sure you've checked
 967          * ContentHandler::canBeUsedOn() first.
 968          *
 969          * @since 1.28
 970          * @param string $model CONTENT_MODEL_XXX constant
 971          */
 972         public function setContentModel( $model ) {
 973                 $this->mContentModel = $model;
 974                 $this->mForcedContentModel = true;
 975         }
 976
 977         /**
 978          * Get the namespace text
 979          *
 980          * @return string|false Namespace text
 981          */
 982         public function getNsText() {
 983                 if ( $this->isExternal() ) {
 984                         // This probably shouldn't even happen,
 985                         // but for interwiki transclusion it sometimes does.
 986                         // Use the canonical namespaces if possible to try to
 987                         // resolve a foreign namespace.
 988                         if ( MWNamespace::exists( $this->mNamespace ) ) {
 989                                 return MWNamespace::getCanonicalName( $this->mNamespace );
 990                         }
 991                 }
 992
 993                 try {
 994                         $formatter = self::getTitleFormatter();
 995                         return $formatter->getNamespaceName( $this->mNamespace, $this->mDbkeyform );
 996                 } catch ( InvalidArgumentException $ex ) {
 997                         wfDebug( __METHOD__ . ': ' . $ex->getMessage() . "\n" );
 998                         return false;
 999                 }
1000         }
1001
1002         /**
1003          * Get the namespace text of the subject (rather than talk) page
1004          *
1005          * @return string Namespace text
1006          */
1007         public function getSubjectNsText() {
1008                 global $wgContLang;
1009                 return $wgContLang->getNsText( MWNamespace::getSubject( $this->mNamespace ) );
1010         }
1011
1012         /**
1013          * Get the namespace text of the talk page
1014          *
1015          * @return string Namespace text
1016          */
1017         public function getTalkNsText() {
1018                 global $wgContLang;
1019                 return $wgContLang->getNsText( MWNamespace::getTalk( $this->mNamespace ) );
1020         }
1021
1022         /**
1023          * Can this title have a corresponding talk page?
1024          *
1025          * @deprecated since 1.30, use canHaveTalkPage() instead.
1026          *
1027          * @return bool True if this title either is a talk page or can have a talk page associated.
1028          */
1029         public function canTalk() {
1030                 return $this->canHaveTalkPage();
1031         }
1032
1033         /**
1034          * Can this title have a corresponding talk page?
1035          *
1036          * @see MWNamespace::hasTalkNamespace
1037          *
1038          * @return bool True if this title either is a talk page or can have a talk page associated.
1039          */
1040         public function canHaveTalkPage() {
1041                 return MWNamespace::hasTalkNamespace( $this->mNamespace );
1042         }
1043
1044         /**
1045          * Is this in a namespace that allows actual pages?
1046          *
1047          * @return bool
1048          */
1049         public function canExist() {
1050                 return $this->mNamespace >= NS_MAIN;
1051         }
1052
1053         /**
1054          * Can this title be added to a user's watchlist?
1055          *
1056          * @return bool
1057          */
1058         public function isWatchable() {
1059                 return !$this->isExternal() && MWNamespace::isWatchable( $this->getNamespace() );
1060         }
1061
1062         /**
1063          * Returns true if this is a special page.
1064          *
1065          * @return bool
1066          */
1067         public function isSpecialPage() {
1068                 return $this->getNamespace() == NS_SPECIAL;
1069         }
1070
1071         /**
1072          * Returns true if this title resolves to the named special page
1073          *
1074          * @param string $name The special page name
1075          * @return bool
1076          */
1077         public function isSpecial( $name ) {
1078                 if ( $this->isSpecialPage() ) {
1079                         list( $thisName, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $this->getDBkey() );
1080                         if ( $name == $thisName ) {
1081                                 return true;
1082                         }
1083                 }
1084                 return false;
1085         }
1086
1087         /**
1088          * If the Title refers to a special page alias which is not the local default, resolve
1089          * the alias, and localise the name as necessary.  Otherwise, return $this
1090          *
1091          * @return Title
1092          */
1093         public function fixSpecialName() {
1094                 if ( $this->isSpecialPage() ) {
1095                         list( $canonicalName, $par ) = SpecialPageFactory::resolveAlias( $this->mDbkeyform );
1096                         if ( $canonicalName ) {
1097                                 $localName = SpecialPageFactory::getLocalNameFor( $canonicalName, $par );
1098                                 if ( $localName != $this->mDbkeyform ) {
1099                                         return self::makeTitle( NS_SPECIAL, $localName );
1100                                 }
1101                         }
1102                 }
1103                 return $this;
1104         }
1105
1106         /**
1107          * Returns true if the title is inside the specified namespace.
1108          *
1109          * Please make use of this instead of comparing to getNamespace()
1110          * This function is much more resistant to changes we may make
1111          * to namespaces than code that makes direct comparisons.
1112          * @param int $ns The namespace
1113          * @return bool
1114          * @since 1.19
1115          */
1116         public function inNamespace( $ns ) {
1117                 return MWNamespace::equals( $this->getNamespace(), $ns );
1118         }
1119
1120         /**
1121          * Returns true if the title is inside one of the specified namespaces.
1122          *
1123          * @param int|int[] $namespaces,... The namespaces to check for
1124          * @return bool
1125          * @since 1.19
1126          */
1127         public function inNamespaces( /* ... */ ) {
1128                 $namespaces = func_get_args();
1129                 if ( count( $namespaces ) > 0 && is_array( $namespaces[0] ) ) {
1130                         $namespaces = $namespaces[0];
1131                 }
1132
1133                 foreach ( $namespaces as $ns ) {
1134                         if ( $this->inNamespace( $ns ) ) {
1135                                 return true;
1136                         }
1137                 }
1138
1139                 return false;
1140         }
1141
1142         /**
1143          * Returns true if the title has the same subject namespace as the
1144          * namespace specified.
1145          * For example this method will take NS_USER and return true if namespace
1146          * is either NS_USER or NS_USER_TALK since both of them have NS_USER
1147          * as their subject namespace.
1148          *
1149          * This is MUCH simpler than individually testing for equivalence
1150          * against both NS_USER and NS_USER_TALK, and is also forward compatible.
1151          * @since 1.19
1152          * @param int $ns
1153          * @return bool
1154          */
1155         public function hasSubjectNamespace( $ns ) {
1156                 return MWNamespace::subjectEquals( $this->getNamespace(), $ns );
1157         }
1158
1159         /**
1160          * Is this Title in a namespace which contains content?
1161          * In other words, is this a content page, for the purposes of calculating
1162          * statistics, etc?
1163          *
1164          * @return bool
1165          */
1166         public function isContentPage() {
1167                 return MWNamespace::isContent( $this->getNamespace() );
1168         }
1169
1170         /**
1171          * Would anybody with sufficient privileges be able to move this page?
1172          * Some pages just aren't movable.
1173          *
1174          * @return bool
1175          */
1176         public function isMovable() {
1177                 if ( !MWNamespace::isMovable( $this->getNamespace() ) || $this->isExternal() ) {
1178                         // Interwiki title or immovable namespace. Hooks don't get to override here
1179                         return false;
1180                 }
1181
1182                 $result = true;
1183                 Hooks::run( 'TitleIsMovable', [ $this, &$result ] );
1184                 return $result;
1185         }
1186
1187         /**
1188          * Is this the mainpage?
1189          * @note Title::newFromText seems to be sufficiently optimized by the title
1190          * cache that we don't need to over-optimize by doing direct comparisons and
1191          * accidentally creating new bugs where $title->equals( Title::newFromText() )
1192          * ends up reporting something differently than $title->isMainPage();
1193          *
1194          * @since 1.18
1195          * @return bool
1196          */
1197         public function isMainPage() {
1198                 return $this->equals( self::newMainPage() );
1199         }
1200
1201         /**
1202          * Is this a subpage?
1203          *
1204          * @return bool
1205          */
1206         public function isSubpage() {
1207                 return MWNamespace::hasSubpages( $this->mNamespace )
1208                         ? strpos( $this->getText(), '/' ) !== false
1209                         : false;
1210         }
1211
1212         /**
1213          * Is this a conversion table for the LanguageConverter?
1214          *
1215          * @return bool
1216          */
1217         public function isConversionTable() {
1218                 // @todo ConversionTable should become a separate content model.
1219
1220                 return $this->getNamespace() == NS_MEDIAWIKI &&
1221                         strpos( $this->getText(), 'Conversiontable/' ) === 0;
1222         }
1223
1224         /**
1225          * Does that page contain wikitext, or it is JS, CSS or whatever?
1226          *
1227          * @return bool
1228          */
1229         public function isWikitextPage() {
1230                 return $this->hasContentModel( CONTENT_MODEL_WIKITEXT );
1231         }
1232
1233         /**
1234          * Could this page contain custom CSS or JavaScript for the global UI.
1235          * This is generally true for pages in the MediaWiki namespace having CONTENT_MODEL_CSS
1236          * or CONTENT_MODEL_JAVASCRIPT.
1237          *
1238          * This method does *not* return true for per-user JS/CSS. Use isCssJsSubpage()
1239          * for that!
1240          *
1241          * Note that this method should not return true for pages that contain and
1242          * show "inactive" CSS or JS.
1243          *
1244          * @return bool
1245          * @todo FIXME: Rename to isSiteConfigPage() and remove deprecated hook
1246          */
1247         public function isCssOrJsPage() {
1248                 $isCssOrJsPage = NS_MEDIAWIKI == $this->mNamespace
1249                         && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1250                                 || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1251
1252                 return $isCssOrJsPage;
1253         }
1254
1255         /**
1256          * Is this a .css or .js subpage of a user page?
1257          * @return bool
1258          * @todo FIXME: Rename to isUserConfigPage()
1259          */
1260         public function isCssJsSubpage() {
1261                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1262                                 && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1263                                         || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) ) );
1264         }
1265
1266         /**
1267          * Trim down a .css or .js subpage title to get the corresponding skin name
1268          *
1269          * @return string Containing skin name from .css or .js subpage title
1270          */
1271         public function getSkinFromCssJsSubpage() {
1272                 $subpage = explode( '/', $this->mTextform );
1273                 $subpage = $subpage[count( $subpage ) - 1];
1274                 $lastdot = strrpos( $subpage, '.' );
1275                 if ( $lastdot === false ) {
1276                         return $subpage; # Never happens: only called for names ending in '.css' or '.js'
1277                 }
1278                 return substr( $subpage, 0, $lastdot );
1279         }
1280
1281         /**
1282          * Is this a .css subpage of a user page?
1283          *
1284          * @return bool
1285          */
1286         public function isCssSubpage() {
1287                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1288                         && $this->hasContentModel( CONTENT_MODEL_CSS ) );
1289         }
1290
1291         /**
1292          * Is this a .js subpage of a user page?
1293          *
1294          * @return bool
1295          */
1296         public function isJsSubpage() {
1297                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1298                         && $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1299         }
1300
1301         /**
1302          * Is this a talk page of some sort?
1303          *
1304          * @return bool
1305          */
1306         public function isTalkPage() {
1307                 return MWNamespace::isTalk( $this->getNamespace() );
1308         }
1309
1310         /**
1311          * Get a Title object associated with the talk page of this article
1312          *
1313          * @return Title The object for the talk page
1314          */
1315         public function getTalkPage() {
1316                 return self::makeTitle( MWNamespace::getTalk( $this->getNamespace() ), $this->getDBkey() );
1317         }
1318
1319         /**
1320          * Get a Title object associated with the talk page of this article,
1321          * if such a talk page can exist.
1322          *
1323          * @return Title The object for the talk page,
1324          *         or null if no associated talk page can exist, according to canHaveTalkPage().
1325          */
1326         public function getTalkPageIfDefined() {
1327                 if ( !$this->canHaveTalkPage() ) {
1328                         return null;
1329                 }
1330
1331                 return $this->getTalkPage();
1332         }
1333
1334         /**
1335          * Get a title object associated with the subject page of this
1336          * talk page
1337          *
1338          * @return Title The object for the subject page
1339          */
1340         public function getSubjectPage() {
1341                 // Is this the same title?
1342                 $subjectNS = MWNamespace::getSubject( $this->getNamespace() );
1343                 if ( $this->getNamespace() == $subjectNS ) {
1344                         return $this;
1345                 }
1346                 return self::makeTitle( $subjectNS, $this->getDBkey() );
1347         }
1348
1349         /**
1350          * Get the other title for this page, if this is a subject page
1351          * get the talk page, if it is a subject page get the talk page
1352          *
1353          * @since 1.25
1354          * @throws MWException
1355          * @return Title
1356          */
1357         public function getOtherPage() {
1358                 if ( $this->isSpecialPage() ) {
1359                         throw new MWException( 'Special pages cannot have other pages' );
1360                 }
1361                 if ( $this->isTalkPage() ) {
1362                         return $this->getSubjectPage();
1363                 } else {
1364                         return $this->getTalkPage();
1365                 }
1366         }
1367
1368         /**
1369          * Get the default namespace index, for when there is no namespace
1370          *
1371          * @return int Default namespace index
1372          */
1373         public function getDefaultNamespace() {
1374                 return $this->mDefaultNamespace;
1375         }
1376
1377         /**
1378          * Get the Title fragment (i.e.\ the bit after the #) in text form
1379          *
1380          * Use Title::hasFragment to check for a fragment
1381          *
1382          * @return string Title fragment
1383          */
1384         public function getFragment() {
1385                 return $this->mFragment;
1386         }
1387
1388         /**
1389          * Check if a Title fragment is set
1390          *
1391          * @return bool
1392          * @since 1.23
1393          */
1394         public function hasFragment() {
1395                 return $this->mFragment !== '';
1396         }
1397
1398         /**
1399          * Get the fragment in URL form, including the "#" character if there is one
1400          * @return string Fragment in URL form
1401          */
1402         public function getFragmentForURL() {
1403                 if ( !$this->hasFragment() ) {
1404                         return '';
1405                 } else {
1406                         return '#' . self::escapeFragmentForURL( $this->getFragment() );
1407                 }
1408         }
1409
1410         /**
1411          * Set the fragment for this title. Removes the first character from the
1412          * specified fragment before setting, so it assumes you're passing it with
1413          * an initial "#".
1414          *
1415          * Deprecated for public use, use Title::makeTitle() with fragment parameter,
1416          * or Title::createFragmentTarget().
1417          * Still in active use privately.
1418          *
1419          * @private
1420          * @param string $fragment Text
1421          */
1422         public function setFragment( $fragment ) {
1423                 $this->mFragment = strtr( substr( $fragment, 1 ), '_', ' ' );
1424         }
1425
1426         /**
1427          * Creates a new Title for a different fragment of the same page.
1428          *
1429          * @since 1.27
1430          * @param string $fragment
1431          * @return Title
1432          */
1433         public function createFragmentTarget( $fragment ) {
1434                 return self::makeTitle(
1435                         $this->getNamespace(),
1436                         $this->getText(),
1437                         $fragment,
1438                         $this->getInterwiki()
1439                 );
1440         }
1441
1442         /**
1443          * Prefix some arbitrary text with the namespace or interwiki prefix
1444          * of this object
1445          *
1446          * @param string $name The text
1447          * @return string The prefixed text
1448          */
1449         private function prefix( $name ) {
1450                 global $wgContLang;
1451
1452                 $p = '';
1453                 if ( $this->isExternal() ) {
1454                         $p = $this->mInterwiki . ':';
1455                 }
1456
1457                 if ( 0 != $this->mNamespace ) {
1458                         $nsText = $this->getNsText();
1459
1460                         if ( $nsText === false ) {
1461                                 // See T165149. Awkward, but better than erroneously linking to the main namespace.
1462                                 $nsText = $wgContLang->getNsText( NS_SPECIAL ) . ":Badtitle/NS{$this->mNamespace}";
1463                         }
1464
1465                         $p .= $nsText . ':';
1466                 }
1467                 return $p . $name;
1468         }
1469
1470         /**
1471          * Get the prefixed database key form
1472          *
1473          * @return string The prefixed title, with underscores and
1474          *  any interwiki and namespace prefixes
1475          */
1476         public function getPrefixedDBkey() {
1477                 $s = $this->prefix( $this->mDbkeyform );
1478                 $s = strtr( $s, ' ', '_' );
1479                 return $s;
1480         }
1481
1482         /**
1483          * Get the prefixed title with spaces.
1484          * This is the form usually used for display
1485          *
1486          * @return string The prefixed title, with spaces
1487          */
1488         public function getPrefixedText() {
1489                 if ( $this->mPrefixedText === null ) {
1490                         $s = $this->prefix( $this->mTextform );
1491                         $s = strtr( $s, '_', ' ' );
1492                         $this->mPrefixedText = $s;
1493                 }
1494                 return $this->mPrefixedText;
1495         }
1496
1497         /**
1498          * Return a string representation of this title
1499          *
1500          * @return string Representation of this title
1501          */
1502         public function __toString() {
1503                 return $this->getPrefixedText();
1504         }
1505
1506         /**
1507          * Get the prefixed title with spaces, plus any fragment
1508          * (part beginning with '#')
1509          *
1510          * @return string The prefixed title, with spaces and the fragment, including '#'
1511          */
1512         public function getFullText() {
1513                 $text = $this->getPrefixedText();
1514                 if ( $this->hasFragment() ) {
1515                         $text .= '#' . $this->getFragment();
1516                 }
1517                 return $text;
1518         }
1519
1520         /**
1521          * Get the root page name text without a namespace, i.e. the leftmost part before any slashes
1522          *
1523          * @par Example:
1524          * @code
1525          * Title::newFromText('User:Foo/Bar/Baz')->getRootText();
1526          * # returns: 'Foo'
1527          * @endcode
1528          *
1529          * @return string Root name
1530          * @since 1.20
1531          */
1532         public function getRootText() {
1533                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1534                         return $this->getText();
1535                 }
1536
1537                 return strtok( $this->getText(), '/' );
1538         }
1539
1540         /**
1541          * Get the root page name title, i.e. the leftmost part before any slashes
1542          *
1543          * @par Example:
1544          * @code
1545          * Title::newFromText('User:Foo/Bar/Baz')->getRootTitle();
1546          * # returns: Title{User:Foo}
1547          * @endcode
1548          *
1549          * @return Title Root title
1550          * @since 1.20
1551          */
1552         public function getRootTitle() {
1553                 return self::makeTitle( $this->getNamespace(), $this->getRootText() );
1554         }
1555
1556         /**
1557          * Get the base page name without a namespace, i.e. the part before the subpage name
1558          *
1559          * @par Example:
1560          * @code
1561          * Title::newFromText('User:Foo/Bar/Baz')->getBaseText();
1562          * # returns: 'Foo/Bar'
1563          * @endcode
1564          *
1565          * @return string Base name
1566          */
1567         public function getBaseText() {
1568                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1569                         return $this->getText();
1570                 }
1571
1572                 $parts = explode( '/', $this->getText() );
1573                 # Don't discard the real title if there's no subpage involved
1574                 if ( count( $parts ) > 1 ) {
1575                         unset( $parts[count( $parts ) - 1] );
1576                 }
1577                 return implode( '/', $parts );
1578         }
1579
1580         /**
1581          * Get the base page name title, i.e. the part before the subpage name
1582          *
1583          * @par Example:
1584          * @code
1585          * Title::newFromText('User:Foo/Bar/Baz')->getBaseTitle();
1586          * # returns: Title{User:Foo/Bar}
1587          * @endcode
1588          *
1589          * @return Title Base title
1590          * @since 1.20
1591          */
1592         public function getBaseTitle() {
1593                 return self::makeTitle( $this->getNamespace(), $this->getBaseText() );
1594         }
1595
1596         /**
1597          * Get the lowest-level subpage name, i.e. the rightmost part after any slashes
1598          *
1599          * @par Example:
1600          * @code
1601          * Title::newFromText('User:Foo/Bar/Baz')->getSubpageText();
1602          * # returns: "Baz"
1603          * @endcode
1604          *
1605          * @return string Subpage name
1606          */
1607         public function getSubpageText() {
1608                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1609                         return $this->mTextform;
1610                 }
1611                 $parts = explode( '/', $this->mTextform );
1612                 return $parts[count( $parts ) - 1];
1613         }
1614
1615         /**
1616          * Get the title for a subpage of the current page
1617          *
1618          * @par Example:
1619          * @code
1620          * Title::newFromText('User:Foo/Bar/Baz')->getSubpage("Asdf");
1621          * # returns: Title{User:Foo/Bar/Baz/Asdf}
1622          * @endcode
1623          *
1624          * @param string $text The subpage name to add to the title
1625          * @return Title Subpage title
1626          * @since 1.20
1627          */
1628         public function getSubpage( $text ) {
1629                 return self::makeTitleSafe( $this->getNamespace(), $this->getText() . '/' . $text );
1630         }
1631
1632         /**
1633          * Get a URL-encoded form of the subpage text
1634          *
1635          * @return string URL-encoded subpage name
1636          */
1637         public function getSubpageUrlForm() {
1638                 $text = $this->getSubpageText();
1639                 $text = wfUrlencode( strtr( $text, ' ', '_' ) );
1640                 return $text;
1641         }
1642
1643         /**
1644          * Get a URL-encoded title (not an actual URL) including interwiki
1645          *
1646          * @return string The URL-encoded form
1647          */
1648         public function getPrefixedURL() {
1649                 $s = $this->prefix( $this->mDbkeyform );
1650                 $s = wfUrlencode( strtr( $s, ' ', '_' ) );
1651                 return $s;
1652         }
1653
1654         /**
1655          * Helper to fix up the get{Canonical,Full,Link,Local,Internal}URL args
1656          * get{Canonical,Full,Link,Local,Internal}URL methods accepted an optional
1657          * second argument named variant. This was deprecated in favor
1658          * of passing an array of option with a "variant" key
1659          * Once $query2 is removed for good, this helper can be dropped
1660          * and the wfArrayToCgi moved to getLocalURL();
1661          *
1662          * @since 1.19 (r105919)
1663          * @param array|string $query
1664          * @param string|string[]|bool $query2
1665          * @return string
1666          */
1667         private static function fixUrlQueryArgs( $query, $query2 = false ) {
1668                 if ( $query2 !== false ) {
1669                         wfDeprecated( "Title::get{Canonical,Full,Link,Local,Internal}URL " .
1670                                 "method called with a second parameter is deprecated. Add your " .
1671                                 "parameter to an array passed as the first parameter.", "1.19" );
1672                 }
1673                 if ( is_array( $query ) ) {
1674                         $query = wfArrayToCgi( $query );
1675                 }
1676                 if ( $query2 ) {
1677                         if ( is_string( $query2 ) ) {
1678                                 // $query2 is a string, we will consider this to be
1679                                 // a deprecated $variant argument and add it to the query
1680                                 $query2 = wfArrayToCgi( [ 'variant' => $query2 ] );
1681                         } else {
1682                                 $query2 = wfArrayToCgi( $query2 );
1683                         }
1684                         // If we have $query content add a & to it first
1685                         if ( $query ) {
1686                                 $query .= '&';
1687                         }
1688                         // Now append the queries together
1689                         $query .= $query2;
1690                 }
1691                 return $query;
1692         }
1693
1694         /**
1695          * Get a real URL referring to this title, with interwiki link and
1696          * fragment
1697          *
1698          * @see self::getLocalURL for the arguments.
1699          * @see wfExpandUrl
1700          * @param string|string[] $query
1701          * @param string|string[]|bool $query2
1702          * @param string $proto Protocol type to use in URL
1703          * @return string The URL
1704          */
1705         public function getFullURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1706                 $query = self::fixUrlQueryArgs( $query, $query2 );
1707
1708                 # Hand off all the decisions on urls to getLocalURL
1709                 $url = $this->getLocalURL( $query );
1710
1711                 # Expand the url to make it a full url. Note that getLocalURL has the
1712                 # potential to output full urls for a variety of reasons, so we use
1713                 # wfExpandUrl instead of simply prepending $wgServer
1714                 $url = wfExpandUrl( $url, $proto );
1715
1716                 # Finally, add the fragment.
1717                 $url .= $this->getFragmentForURL();
1718                 // Avoid PHP 7.1 warning from passing $this by reference
1719                 $titleRef = $this;
1720                 Hooks::run( 'GetFullURL', [ &$titleRef, &$url, $query ] );
1721                 return $url;
1722         }
1723
1724         /**
1725          * Get a url appropriate for making redirects based on an untrusted url arg
1726          *
1727          * This is basically the same as getFullUrl(), but in the case of external
1728          * interwikis, we send the user to a landing page, to prevent possible
1729          * phishing attacks and the like.
1730          *
1731          * @note Uses current protocol by default, since technically relative urls
1732          *   aren't allowed in redirects per HTTP spec, so this is not suitable for
1733          *   places where the url gets cached, as might pollute between
1734          *   https and non-https users.
1735          * @see self::getLocalURL for the arguments.
1736          * @param array|string $query
1737          * @param string $proto Protocol type to use in URL
1738          * @return String. A url suitable to use in an HTTP location header.
1739          */
1740         public function getFullUrlForRedirect( $query = '', $proto = PROTO_CURRENT ) {
1741                 $target = $this;
1742                 if ( $this->isExternal() ) {
1743                         $target = SpecialPage::getTitleFor(
1744                                 'GoToInterwiki',
1745                                 $this->getPrefixedDBKey()
1746                         );
1747                 }
1748                 return $target->getFullUrl( $query, false, $proto );
1749         }
1750
1751         /**
1752          * Get a URL with no fragment or server name (relative URL) from a Title object.
1753          * If this page is generated with action=render, however,
1754          * $wgServer is prepended to make an absolute URL.
1755          *
1756          * @see self::getFullURL to always get an absolute URL.
1757          * @see self::getLinkURL to always get a URL that's the simplest URL that will be
1758          *  valid to link, locally, to the current Title.
1759          * @see self::newFromText to produce a Title object.
1760          *
1761          * @param string|string[] $query An optional query string,
1762          *   not used for interwiki links. Can be specified as an associative array as well,
1763          *   e.g., array( 'action' => 'edit' ) (keys and values will be URL-escaped).
1764          *   Some query patterns will trigger various shorturl path replacements.
1765          * @param string|string[]|bool $query2 An optional secondary query array. This one MUST
1766          *   be an array. If a string is passed it will be interpreted as a deprecated
1767          *   variant argument and urlencoded into a variant= argument.
1768          *   This second query argument will be added to the $query
1769          *   The second parameter is deprecated since 1.19. Pass it as a key,value
1770          *   pair in the first parameter array instead.
1771          *
1772          * @return string String of the URL.
1773          */
1774         public function getLocalURL( $query = '', $query2 = false ) {
1775                 global $wgArticlePath, $wgScript, $wgServer, $wgRequest;
1776
1777                 $query = self::fixUrlQueryArgs( $query, $query2 );
1778
1779                 $interwiki = self::getInterwikiLookup()->fetch( $this->mInterwiki );
1780                 if ( $interwiki ) {
1781                         $namespace = $this->getNsText();
1782                         if ( $namespace != '' ) {
1783                                 # Can this actually happen? Interwikis shouldn't be parsed.
1784                                 # Yes! It can in interwiki transclusion. But... it probably shouldn't.
1785                                 $namespace .= ':';
1786                         }
1787                         $url = $interwiki->getURL( $namespace . $this->getDBkey() );
1788                         $url = wfAppendQuery( $url, $query );
1789                 } else {
1790                         $dbkey = wfUrlencode( $this->getPrefixedDBkey() );
1791                         if ( $query == '' ) {
1792                                 $url = str_replace( '$1', $dbkey, $wgArticlePath );
1793                                 // Avoid PHP 7.1 warning from passing $this by reference
1794                                 $titleRef = $this;
1795                                 Hooks::run( 'GetLocalURL::Article', [ &$titleRef, &$url ] );
1796                         } else {
1797                                 global $wgVariantArticlePath, $wgActionPaths, $wgContLang;
1798                                 $url = false;
1799                                 $matches = [];
1800
1801                                 if ( !empty( $wgActionPaths )
1802                                         && preg_match( '/^(.*&|)action=([^&]*)(&(.*)|)$/', $query, $matches )
1803                                 ) {
1804                                         $action = urldecode( $matches[2] );
1805                                         if ( isset( $wgActionPaths[$action] ) ) {
1806                                                 $query = $matches[1];
1807                                                 if ( isset( $matches[4] ) ) {
1808                                                         $query .= $matches[4];
1809                                                 }
1810                                                 $url = str_replace( '$1', $dbkey, $wgActionPaths[$action] );
1811                                                 if ( $query != '' ) {
1812                                                         $url = wfAppendQuery( $url, $query );
1813                                                 }
1814                                         }
1815                                 }
1816
1817                                 if ( $url === false
1818                                         && $wgVariantArticlePath
1819                                         && preg_match( '/^variant=([^&]*)$/', $query, $matches )
1820                                         && $this->getPageLanguage()->equals( $wgContLang )
1821                                         && $this->getPageLanguage()->hasVariants()
1822                                 ) {
1823                                         $variant = urldecode( $matches[1] );
1824                                         if ( $this->getPageLanguage()->hasVariant( $variant ) ) {
1825                                                 // Only do the variant replacement if the given variant is a valid
1826                                                 // variant for the page's language.
1827                                                 $url = str_replace( '$2', urlencode( $variant ), $wgVariantArticlePath );
1828                                                 $url = str_replace( '$1', $dbkey, $url );
1829                                         }
1830                                 }
1831
1832                                 if ( $url === false ) {
1833                                         if ( $query == '-' ) {
1834                                                 $query = '';
1835                                         }
1836                                         $url = "{$wgScript}?title={$dbkey}&{$query}";
1837                                 }
1838                         }
1839                         // Avoid PHP 7.1 warning from passing $this by reference
1840                         $titleRef = $this;
1841                         Hooks::run( 'GetLocalURL::Internal', [ &$titleRef, &$url, $query ] );
1842
1843                         // @todo FIXME: This causes breakage in various places when we
1844                         // actually expected a local URL and end up with dupe prefixes.
1845                         if ( $wgRequest->getVal( 'action' ) == 'render' ) {
1846                                 $url = $wgServer . $url;
1847                         }
1848                 }
1849                 // Avoid PHP 7.1 warning from passing $this by reference
1850                 $titleRef = $this;
1851                 Hooks::run( 'GetLocalURL', [ &$titleRef, &$url, $query ] );
1852                 return $url;
1853         }
1854
1855         /**
1856          * Get a URL that's the simplest URL that will be valid to link, locally,
1857          * to the current Title.  It includes the fragment, but does not include
1858          * the server unless action=render is used (or the link is external).  If
1859          * there's a fragment but the prefixed text is empty, we just return a link
1860          * to the fragment.
1861          *
1862          * The result obviously should not be URL-escaped, but does need to be
1863          * HTML-escaped if it's being output in HTML.
1864          *
1865          * @param string|string[] $query
1866          * @param bool $query2
1867          * @param string|int|bool $proto A PROTO_* constant on how the URL should be expanded,
1868          *                               or false (default) for no expansion
1869          * @see self::getLocalURL for the arguments.
1870          * @return string The URL
1871          */
1872         public function getLinkURL( $query = '', $query2 = false, $proto = false ) {
1873                 if ( $this->isExternal() || $proto !== false ) {
1874                         $ret = $this->getFullURL( $query, $query2, $proto );
1875                 } elseif ( $this->getPrefixedText() === '' && $this->hasFragment() ) {
1876                         $ret = $this->getFragmentForURL();
1877                 } else {
1878                         $ret = $this->getLocalURL( $query, $query2 ) . $this->getFragmentForURL();
1879                 }
1880                 return $ret;
1881         }
1882
1883         /**
1884          * Get the URL form for an internal link.
1885          * - Used in various CDN-related code, in case we have a different
1886          * internal hostname for the server from the exposed one.
1887          *
1888          * This uses $wgInternalServer to qualify the path, or $wgServer
1889          * if $wgInternalServer is not set. If the server variable used is
1890          * protocol-relative, the URL will be expanded to http://
1891          *
1892          * @see self::getLocalURL for the arguments.
1893          * @return string The URL
1894          */
1895         public function getInternalURL( $query = '', $query2 = false ) {
1896                 global $wgInternalServer, $wgServer;
1897                 $query = self::fixUrlQueryArgs( $query, $query2 );
1898                 $server = $wgInternalServer !== false ? $wgInternalServer : $wgServer;
1899                 $url = wfExpandUrl( $server . $this->getLocalURL( $query ), PROTO_HTTP );
1900                 // Avoid PHP 7.1 warning from passing $this by reference
1901                 $titleRef = $this;
1902                 Hooks::run( 'GetInternalURL', [ &$titleRef, &$url, $query ] );
1903                 return $url;
1904         }
1905
1906         /**
1907          * Get the URL for a canonical link, for use in things like IRC and
1908          * e-mail notifications. Uses $wgCanonicalServer and the
1909          * GetCanonicalURL hook.
1910          *
1911          * NOTE: Unlike getInternalURL(), the canonical URL includes the fragment
1912          *
1913          * @see self::getLocalURL for the arguments.
1914          * @return string The URL
1915          * @since 1.18
1916          */
1917         public function getCanonicalURL( $query = '', $query2 = false ) {
1918                 $query = self::fixUrlQueryArgs( $query, $query2 );
1919                 $url = wfExpandUrl( $this->getLocalURL( $query ) . $this->getFragmentForURL(), PROTO_CANONICAL );
1920                 // Avoid PHP 7.1 warning from passing $this by reference
1921                 $titleRef = $this;
1922                 Hooks::run( 'GetCanonicalURL', [ &$titleRef, &$url, $query ] );
1923                 return $url;
1924         }
1925
1926         /**
1927          * Get the edit URL for this Title
1928          *
1929          * @return string The URL, or a null string if this is an interwiki link
1930          */
1931         public function getEditURL() {
1932                 if ( $this->isExternal() ) {
1933                         return '';
1934                 }
1935                 $s = $this->getLocalURL( 'action=edit' );
1936
1937                 return $s;
1938         }
1939
1940         /**
1941          * Can $user perform $action on this page?
1942          * This skips potentially expensive cascading permission checks
1943          * as well as avoids expensive error formatting
1944          *
1945          * Suitable for use for nonessential UI controls in common cases, but
1946          * _not_ for functional access control.
1947          *
1948          * May provide false positives, but should never provide a false negative.
1949          *
1950          * @param string $action Action that permission needs to be checked for
1951          * @param User $user User to check (since 1.19); $wgUser will be used if not provided.
1952          * @return bool
1953          */
1954         public function quickUserCan( $action, $user = null ) {
1955                 return $this->userCan( $action, $user, false );
1956         }
1957
1958         /**
1959          * Can $user perform $action on this page?
1960          *
1961          * @param string $action Action that permission needs to be checked for
1962          * @param User $user User to check (since 1.19); $wgUser will be used if not
1963          *   provided.
1964          * @param string $rigor Same format as Title::getUserPermissionsErrors()
1965          * @return bool
1966          */
1967         public function userCan( $action, $user = null, $rigor = 'secure' ) {
1968                 if ( !$user instanceof User ) {
1969                         global $wgUser;
1970                         $user = $wgUser;
1971                 }
1972
1973                 return !count( $this->getUserPermissionsErrorsInternal( $action, $user, $rigor, true ) );
1974         }
1975
1976         /**
1977          * Can $user perform $action on this page?
1978          *
1979          * @todo FIXME: This *does not* check throttles (User::pingLimiter()).
1980          *
1981          * @param string $action Action that permission needs to be checked for
1982          * @param User $user User to check
1983          * @param string $rigor One of (quick,full,secure)
1984          *   - quick  : does cheap permission checks from replica DBs (usable for GUI creation)
1985          *   - full   : does cheap and expensive checks possibly from a replica DB
1986          *   - secure : does cheap and expensive checks, using the master as needed
1987          * @param array $ignoreErrors Array of Strings Set this to a list of message keys
1988          *   whose corresponding errors may be ignored.
1989          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
1990          */
1991         public function getUserPermissionsErrors(
1992                 $action, $user, $rigor = 'secure', $ignoreErrors = []
1993         ) {
1994                 $errors = $this->getUserPermissionsErrorsInternal( $action, $user, $rigor );
1995
1996                 // Remove the errors being ignored.
1997                 foreach ( $errors as $index => $error ) {
1998                         $errKey = is_array( $error ) ? $error[0] : $error;
1999
2000                         if ( in_array( $errKey, $ignoreErrors ) ) {
2001                                 unset( $errors[$index] );
2002                         }
2003                         if ( $errKey instanceof MessageSpecifier && in_array( $errKey->getKey(), $ignoreErrors ) ) {
2004                                 unset( $errors[$index] );
2005                         }
2006                 }
2007
2008                 return $errors;
2009         }
2010
2011         /**
2012          * Permissions checks that fail most often, and which are easiest to test.
2013          *
2014          * @param string $action The action to check
2015          * @param User $user User to check
2016          * @param array $errors List of current errors
2017          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2018          * @param bool $short Short circuit on first error
2019          *
2020          * @return array List of errors
2021          */
2022         private function checkQuickPermissions( $action, $user, $errors, $rigor, $short ) {
2023                 if ( !Hooks::run( 'TitleQuickPermissions',
2024                         [ $this, $user, $action, &$errors, ( $rigor !== 'quick' ), $short ] )
2025                 ) {
2026                         return $errors;
2027                 }
2028
2029                 if ( $action == 'create' ) {
2030                         if (
2031                                 ( $this->isTalkPage() && !$user->isAllowed( 'createtalk' ) ) ||
2032                                 ( !$this->isTalkPage() && !$user->isAllowed( 'createpage' ) )
2033                         ) {
2034                                 $errors[] = $user->isAnon() ? [ 'nocreatetext' ] : [ 'nocreate-loggedin' ];
2035                         }
2036                 } elseif ( $action == 'move' ) {
2037                         if ( !$user->isAllowed( 'move-rootuserpages' )
2038                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
2039                                 // Show user page-specific message only if the user can move other pages
2040                                 $errors[] = [ 'cant-move-user-page' ];
2041                         }
2042
2043                         // Check if user is allowed to move files if it's a file
2044                         if ( $this->mNamespace == NS_FILE && !$user->isAllowed( 'movefile' ) ) {
2045                                 $errors[] = [ 'movenotallowedfile' ];
2046                         }
2047
2048                         // Check if user is allowed to move category pages if it's a category page
2049                         if ( $this->mNamespace == NS_CATEGORY && !$user->isAllowed( 'move-categorypages' ) ) {
2050                                 $errors[] = [ 'cant-move-category-page' ];
2051                         }
2052
2053                         if ( !$user->isAllowed( 'move' ) ) {
2054                                 // User can't move anything
2055                                 $userCanMove = User::groupHasPermission( 'user', 'move' );
2056                                 $autoconfirmedCanMove = User::groupHasPermission( 'autoconfirmed', 'move' );
2057                                 if ( $user->isAnon() && ( $userCanMove || $autoconfirmedCanMove ) ) {
2058                                         // custom message if logged-in users without any special rights can move
2059                                         $errors[] = [ 'movenologintext' ];
2060                                 } else {
2061                                         $errors[] = [ 'movenotallowed' ];
2062                                 }
2063                         }
2064                 } elseif ( $action == 'move-target' ) {
2065                         if ( !$user->isAllowed( 'move' ) ) {
2066                                 // User can't move anything
2067                                 $errors[] = [ 'movenotallowed' ];
2068                         } elseif ( !$user->isAllowed( 'move-rootuserpages' )
2069                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
2070                                 // Show user page-specific message only if the user can move other pages
2071                                 $errors[] = [ 'cant-move-to-user-page' ];
2072                         } elseif ( !$user->isAllowed( 'move-categorypages' )
2073                                         && $this->mNamespace == NS_CATEGORY ) {
2074                                 // Show category page-specific message only if the user can move other pages
2075                                 $errors[] = [ 'cant-move-to-category-page' ];
2076                         }
2077                 } elseif ( !$user->isAllowed( $action ) ) {
2078                         $errors[] = $this->missingPermissionError( $action, $short );
2079                 }
2080
2081                 return $errors;
2082         }
2083
2084         /**
2085          * Add the resulting error code to the errors array
2086          *
2087          * @param array $errors List of current errors
2088          * @param array $result Result of errors
2089          *
2090          * @return array List of errors
2091          */
2092         private function resultToError( $errors, $result ) {
2093                 if ( is_array( $result ) && count( $result ) && !is_array( $result[0] ) ) {
2094                         // A single array representing an error
2095                         $errors[] = $result;
2096                 } elseif ( is_array( $result ) && is_array( $result[0] ) ) {
2097                         // A nested array representing multiple errors
2098                         $errors = array_merge( $errors, $result );
2099                 } elseif ( $result !== '' && is_string( $result ) ) {
2100                         // A string representing a message-id
2101                         $errors[] = [ $result ];
2102                 } elseif ( $result instanceof MessageSpecifier ) {
2103                         // A message specifier representing an error
2104                         $errors[] = [ $result ];
2105                 } elseif ( $result === false ) {
2106                         // a generic "We don't want them to do that"
2107                         $errors[] = [ 'badaccess-group0' ];
2108                 }
2109                 return $errors;
2110         }
2111
2112         /**
2113          * Check various permission hooks
2114          *
2115          * @param string $action The action to check
2116          * @param User $user User to check
2117          * @param array $errors List of current errors
2118          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2119          * @param bool $short Short circuit on first error
2120          *
2121          * @return array List of errors
2122          */
2123         private function checkPermissionHooks( $action, $user, $errors, $rigor, $short ) {
2124                 // Use getUserPermissionsErrors instead
2125                 $result = '';
2126                 // Avoid PHP 7.1 warning from passing $this by reference
2127                 $titleRef = $this;
2128                 if ( !Hooks::run( 'userCan', [ &$titleRef, &$user, $action, &$result ] ) ) {
2129                         return $result ? [] : [ [ 'badaccess-group0' ] ];
2130                 }
2131                 // Check getUserPermissionsErrors hook
2132                 // Avoid PHP 7.1 warning from passing $this by reference
2133                 $titleRef = $this;
2134                 if ( !Hooks::run( 'getUserPermissionsErrors', [ &$titleRef, &$user, $action, &$result ] ) ) {
2135                         $errors = $this->resultToError( $errors, $result );
2136                 }
2137                 // Check getUserPermissionsErrorsExpensive hook
2138                 if (
2139                         $rigor !== 'quick'
2140                         && !( $short && count( $errors ) > 0 )
2141                         && !Hooks::run( 'getUserPermissionsErrorsExpensive', [ &$titleRef, &$user, $action, &$result ] )
2142                 ) {
2143                         $errors = $this->resultToError( $errors, $result );
2144                 }
2145
2146                 return $errors;
2147         }
2148
2149         /**
2150          * Check permissions on special pages & namespaces
2151          *
2152          * @param string $action The action to check
2153          * @param User $user User to check
2154          * @param array $errors List of current errors
2155          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2156          * @param bool $short Short circuit on first error
2157          *
2158          * @return array List of errors
2159          */
2160         private function checkSpecialsAndNSPermissions( $action, $user, $errors, $rigor, $short ) {
2161                 # Only 'createaccount' can be performed on special pages,
2162                 # which don't actually exist in the DB.
2163                 if ( $this->isSpecialPage() && $action !== 'createaccount' ) {
2164                         $errors[] = [ 'ns-specialprotected' ];
2165                 }
2166
2167                 # Check $wgNamespaceProtection for restricted namespaces
2168                 if ( $this->isNamespaceProtected( $user ) ) {
2169                         $ns = $this->mNamespace == NS_MAIN ?
2170                                 wfMessage( 'nstab-main' )->text() : $this->getNsText();
2171                         $errors[] = $this->mNamespace == NS_MEDIAWIKI ?
2172                                 [ 'protectedinterface', $action ] : [ 'namespaceprotected', $ns, $action ];
2173                 }
2174
2175                 return $errors;
2176         }
2177
2178         /**
2179          * Check CSS/JS sub-page permissions
2180          *
2181          * @param string $action The action to check
2182          * @param User $user User to check
2183          * @param array $errors List of current errors
2184          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2185          * @param bool $short Short circuit on first error
2186          *
2187          * @return array List of errors
2188          */
2189         private function checkCSSandJSPermissions( $action, $user, $errors, $rigor, $short ) {
2190                 # Protect css/js subpages of user pages
2191                 # XXX: this might be better using restrictions
2192                 if ( $action != 'patrol' ) {
2193                         if ( preg_match( '/^' . preg_quote( $user->getName(), '/' ) . '\//', $this->mTextform ) ) {
2194                                 if ( $this->isCssSubpage() && !$user->isAllowedAny( 'editmyusercss', 'editusercss' ) ) {
2195                                         $errors[] = [ 'mycustomcssprotected', $action ];
2196                                 } elseif ( $this->isJsSubpage() && !$user->isAllowedAny( 'editmyuserjs', 'edituserjs' ) ) {
2197                                         $errors[] = [ 'mycustomjsprotected', $action ];
2198                                 }
2199                         } else {
2200                                 if ( $this->isCssSubpage() && !$user->isAllowed( 'editusercss' ) ) {
2201                                         $errors[] = [ 'customcssprotected', $action ];
2202                                 } elseif ( $this->isJsSubpage() && !$user->isAllowed( 'edituserjs' ) ) {
2203                                         $errors[] = [ 'customjsprotected', $action ];
2204                                 }
2205                         }
2206                 }
2207
2208                 return $errors;
2209         }
2210
2211         /**
2212          * Check against page_restrictions table requirements on this
2213          * page. The user must possess all required rights for this
2214          * action.
2215          *
2216          * @param string $action The action to check
2217          * @param User $user User to check
2218          * @param array $errors List of current errors
2219          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2220          * @param bool $short Short circuit on first error
2221          *
2222          * @return array List of errors
2223          */
2224         private function checkPageRestrictions( $action, $user, $errors, $rigor, $short ) {
2225                 foreach ( $this->getRestrictions( $action ) as $right ) {
2226                         // Backwards compatibility, rewrite sysop -> editprotected
2227                         if ( $right == 'sysop' ) {
2228                                 $right = 'editprotected';
2229                         }
2230                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2231                         if ( $right == 'autoconfirmed' ) {
2232                                 $right = 'editsemiprotected';
2233                         }
2234                         if ( $right == '' ) {
2235                                 continue;
2236                         }
2237                         if ( !$user->isAllowed( $right ) ) {
2238                                 $errors[] = [ 'protectedpagetext', $right, $action ];
2239                         } elseif ( $this->mCascadeRestriction && !$user->isAllowed( 'protect' ) ) {
2240                                 $errors[] = [ 'protectedpagetext', 'protect', $action ];
2241                         }
2242                 }
2243
2244                 return $errors;
2245         }
2246
2247         /**
2248          * Check restrictions on cascading pages.
2249          *
2250          * @param string $action The action to check
2251          * @param User $user User to check
2252          * @param array $errors List of current errors
2253          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2254          * @param bool $short Short circuit on first error
2255          *
2256          * @return array List of errors
2257          */
2258         private function checkCascadingSourcesRestrictions( $action, $user, $errors, $rigor, $short ) {
2259                 if ( $rigor !== 'quick' && !$this->isCssJsSubpage() ) {
2260                         # We /could/ use the protection level on the source page, but it's
2261                         # fairly ugly as we have to establish a precedence hierarchy for pages
2262                         # included by multiple cascade-protected pages. So just restrict
2263                         # it to people with 'protect' permission, as they could remove the
2264                         # protection anyway.
2265                         list( $cascadingSources, $restrictions ) = $this->getCascadeProtectionSources();
2266                         # Cascading protection depends on more than this page...
2267                         # Several cascading protected pages may include this page...
2268                         # Check each cascading level
2269                         # This is only for protection restrictions, not for all actions
2270                         if ( isset( $restrictions[$action] ) ) {
2271                                 foreach ( $restrictions[$action] as $right ) {
2272                                         // Backwards compatibility, rewrite sysop -> editprotected
2273                                         if ( $right == 'sysop' ) {
2274                                                 $right = 'editprotected';
2275                                         }
2276                                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2277                                         if ( $right == 'autoconfirmed' ) {
2278                                                 $right = 'editsemiprotected';
2279                                         }
2280                                         if ( $right != '' && !$user->isAllowedAll( 'protect', $right ) ) {
2281                                                 $pages = '';
2282                                                 foreach ( $cascadingSources as $page ) {
2283                                                         $pages .= '* [[:' . $page->getPrefixedText() . "]]\n";
2284                                                 }
2285                                                 $errors[] = [ 'cascadeprotected', count( $cascadingSources ), $pages, $action ];
2286                                         }
2287                                 }
2288                         }
2289                 }
2290
2291                 return $errors;
2292         }
2293
2294         /**
2295          * Check action permissions not already checked in checkQuickPermissions
2296          *
2297          * @param string $action The action to check
2298          * @param User $user User to check
2299          * @param array $errors List of current errors
2300          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2301          * @param bool $short Short circuit on first error
2302          *
2303          * @return array List of errors
2304          */
2305         private function checkActionPermissions( $action, $user, $errors, $rigor, $short ) {
2306                 global $wgDeleteRevisionsLimit, $wgLang;
2307
2308                 if ( $action == 'protect' ) {
2309                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit', $user, $rigor, true ) ) ) {
2310                                 // If they can't edit, they shouldn't protect.
2311                                 $errors[] = [ 'protect-cantedit' ];
2312                         }
2313                 } elseif ( $action == 'create' ) {
2314                         $title_protection = $this->getTitleProtection();
2315                         if ( $title_protection ) {
2316                                 if ( $title_protection['permission'] == ''
2317                                         || !$user->isAllowed( $title_protection['permission'] )
2318                                 ) {
2319                                         $errors[] = [
2320                                                 'titleprotected',
2321                                                 User::whoIs( $title_protection['user'] ),
2322                                                 $title_protection['reason']
2323                                         ];
2324                                 }
2325                         }
2326                 } elseif ( $action == 'move' ) {
2327                         // Check for immobile pages
2328                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2329                                 // Specific message for this case
2330                                 $errors[] = [ 'immobile-source-namespace', $this->getNsText() ];
2331                         } elseif ( !$this->isMovable() ) {
2332                                 // Less specific message for rarer cases
2333                                 $errors[] = [ 'immobile-source-page' ];
2334                         }
2335                 } elseif ( $action == 'move-target' ) {
2336                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2337                                 $errors[] = [ 'immobile-target-namespace', $this->getNsText() ];
2338                         } elseif ( !$this->isMovable() ) {
2339                                 $errors[] = [ 'immobile-target-page' ];
2340                         }
2341                 } elseif ( $action == 'delete' ) {
2342                         $tempErrors = $this->checkPageRestrictions( 'edit', $user, [], $rigor, true );
2343                         if ( !$tempErrors ) {
2344                                 $tempErrors = $this->checkCascadingSourcesRestrictions( 'edit',
2345                                         $user, $tempErrors, $rigor, true );
2346                         }
2347                         if ( $tempErrors ) {
2348                                 // If protection keeps them from editing, they shouldn't be able to delete.
2349                                 $errors[] = [ 'deleteprotected' ];
2350                         }
2351                         if ( $rigor !== 'quick' && $wgDeleteRevisionsLimit
2352                                 && !$this->userCan( 'bigdelete', $user ) && $this->isBigDeletion()
2353                         ) {
2354                                 $errors[] = [ 'delete-toobig', $wgLang->formatNum( $wgDeleteRevisionsLimit ) ];
2355                         }
2356                 } elseif ( $action === 'undelete' ) {
2357                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit', $user, $rigor, true ) ) ) {
2358                                 // Undeleting implies editing
2359                                 $errors[] = [ 'undelete-cantedit' ];
2360                         }
2361                         if ( !$this->exists()
2362                                 && count( $this->getUserPermissionsErrorsInternal( 'create', $user, $rigor, true ) )
2363                         ) {
2364                                 // Undeleting where nothing currently exists implies creating
2365                                 $errors[] = [ 'undelete-cantcreate' ];
2366                         }
2367                 }
2368                 return $errors;
2369         }
2370
2371         /**
2372          * Check that the user isn't blocked from editing.
2373          *
2374          * @param string $action The action to check
2375          * @param User $user User to check
2376          * @param array $errors List of current errors
2377          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2378          * @param bool $short Short circuit on first error
2379          *
2380          * @return array List of errors
2381          */
2382         private function checkUserBlock( $action, $user, $errors, $rigor, $short ) {
2383                 global $wgEmailConfirmToEdit, $wgBlockDisablesLogin;
2384                 // Account creation blocks handled at userlogin.
2385                 // Unblocking handled in SpecialUnblock
2386                 if ( $rigor === 'quick' || in_array( $action, [ 'createaccount', 'unblock' ] ) ) {
2387                         return $errors;
2388                 }
2389
2390                 // Optimize for a very common case
2391                 if ( $action === 'read' && !$wgBlockDisablesLogin ) {
2392                         return $errors;
2393                 }
2394
2395                 if ( $wgEmailConfirmToEdit && !$user->isEmailConfirmed() ) {
2396                         $errors[] = [ 'confirmedittext' ];
2397                 }
2398
2399                 $useSlave = ( $rigor !== 'secure' );
2400                 if ( ( $action == 'edit' || $action == 'create' )
2401                         && !$user->isBlockedFrom( $this, $useSlave )
2402                 ) {
2403                         // Don't block the user from editing their own talk page unless they've been
2404                         // explicitly blocked from that too.
2405                 } elseif ( $user->isBlocked() && $user->getBlock()->prevents( $action ) !== false ) {
2406                         // @todo FIXME: Pass the relevant context into this function.
2407                         $errors[] = $user->getBlock()->getPermissionsError( RequestContext::getMain() );
2408                 }
2409
2410                 return $errors;
2411         }
2412
2413         /**
2414          * Check that the user is allowed to read this page.
2415          *
2416          * @param string $action The action to check
2417          * @param User $user User to check
2418          * @param array $errors List of current errors
2419          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2420          * @param bool $short Short circuit on first error
2421          *
2422          * @return array List of errors
2423          */
2424         private function checkReadPermissions( $action, $user, $errors, $rigor, $short ) {
2425                 global $wgWhitelistRead, $wgWhitelistReadRegexp;
2426
2427                 $whitelisted = false;
2428                 if ( User::isEveryoneAllowed( 'read' ) ) {
2429                         # Shortcut for public wikis, allows skipping quite a bit of code
2430                         $whitelisted = true;
2431                 } elseif ( $user->isAllowed( 'read' ) ) {
2432                         # If the user is allowed to read pages, he is allowed to read all pages
2433                         $whitelisted = true;
2434                 } elseif ( $this->isSpecial( 'Userlogin' )
2435                         || $this->isSpecial( 'PasswordReset' )
2436                         || $this->isSpecial( 'Userlogout' )
2437                 ) {
2438                         # Always grant access to the login page.
2439                         # Even anons need to be able to log in.
2440                         $whitelisted = true;
2441                 } elseif ( is_array( $wgWhitelistRead ) && count( $wgWhitelistRead ) ) {
2442                         # Time to check the whitelist
2443                         # Only do these checks is there's something to check against
2444                         $name = $this->getPrefixedText();
2445                         $dbName = $this->getPrefixedDBkey();
2446
2447                         // Check for explicit whitelisting with and without underscores
2448                         if ( in_array( $name, $wgWhitelistRead, true ) || in_array( $dbName, $wgWhitelistRead, true ) ) {
2449                                 $whitelisted = true;
2450                         } elseif ( $this->getNamespace() == NS_MAIN ) {
2451                                 # Old settings might have the title prefixed with
2452                                 # a colon for main-namespace pages
2453                                 if ( in_array( ':' . $name, $wgWhitelistRead ) ) {
2454                                         $whitelisted = true;
2455                                 }
2456                         } elseif ( $this->isSpecialPage() ) {
2457                                 # If it's a special page, ditch the subpage bit and check again
2458                                 $name = $this->getDBkey();
2459                                 list( $name, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $name );
2460                                 if ( $name ) {
2461                                         $pure = SpecialPage::getTitleFor( $name )->getPrefixedText();
2462                                         if ( in_array( $pure, $wgWhitelistRead, true ) ) {
2463                                                 $whitelisted = true;
2464                                         }
2465                                 }
2466                         }
2467                 }
2468
2469                 if ( !$whitelisted && is_array( $wgWhitelistReadRegexp ) && !empty( $wgWhitelistReadRegexp ) ) {
2470                         $name = $this->getPrefixedText();
2471                         // Check for regex whitelisting
2472                         foreach ( $wgWhitelistReadRegexp as $listItem ) {
2473                                 if ( preg_match( $listItem, $name ) ) {
2474                                         $whitelisted = true;
2475                                         break;
2476                                 }
2477                         }
2478                 }
2479
2480                 if ( !$whitelisted ) {
2481                         # If the title is not whitelisted, give extensions a chance to do so...
2482                         Hooks::run( 'TitleReadWhitelist', [ $this, $user, &$whitelisted ] );
2483                         if ( !$whitelisted ) {
2484                                 $errors[] = $this->missingPermissionError( $action, $short );
2485                         }
2486                 }
2487
2488                 return $errors;
2489         }
2490
2491         /**
2492          * Get a description array when the user doesn't have the right to perform
2493          * $action (i.e. when User::isAllowed() returns false)
2494          *
2495          * @param string $action The action to check
2496          * @param bool $short Short circuit on first error
2497          * @return array Array containing an error message key and any parameters
2498          */
2499         private function missingPermissionError( $action, $short ) {
2500                 // We avoid expensive display logic for quickUserCan's and such
2501                 if ( $short ) {
2502                         return [ 'badaccess-group0' ];
2503                 }
2504
2505                 return User::newFatalPermissionDeniedStatus( $action )->getErrorsArray()[0];
2506         }
2507
2508         /**
2509          * Can $user perform $action on this page? This is an internal function,
2510          * with multiple levels of checks depending on performance needs; see $rigor below.
2511          * It does not check wfReadOnly().
2512          *
2513          * @param string $action Action that permission needs to be checked for
2514          * @param User $user User to check
2515          * @param string $rigor One of (quick,full,secure)
2516          *   - quick  : does cheap permission checks from replica DBs (usable for GUI creation)
2517          *   - full   : does cheap and expensive checks possibly from a replica DB
2518          *   - secure : does cheap and expensive checks, using the master as needed
2519          * @param bool $short Set this to true to stop after the first permission error.
2520          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
2521          */
2522         protected function getUserPermissionsErrorsInternal(
2523                 $action, $user, $rigor = 'secure', $short = false
2524         ) {
2525                 if ( $rigor === true ) {
2526                         $rigor = 'secure'; // b/c
2527                 } elseif ( $rigor === false ) {
2528                         $rigor = 'quick'; // b/c
2529                 } elseif ( !in_array( $rigor, [ 'quick', 'full', 'secure' ] ) ) {
2530                         throw new Exception( "Invalid rigor parameter '$rigor'." );
2531                 }
2532
2533                 # Read has special handling
2534                 if ( $action == 'read' ) {
2535                         $checks = [
2536                                 'checkPermissionHooks',
2537                                 'checkReadPermissions',
2538                                 'checkUserBlock', // for wgBlockDisablesLogin
2539                         ];
2540                 # Don't call checkSpecialsAndNSPermissions or checkCSSandJSPermissions
2541                 # here as it will lead to duplicate error messages. This is okay to do
2542                 # since anywhere that checks for create will also check for edit, and
2543                 # those checks are called for edit.
2544                 } elseif ( $action == 'create' ) {
2545                         $checks = [
2546                                 'checkQuickPermissions',
2547                                 'checkPermissionHooks',
2548                                 'checkPageRestrictions',
2549                                 'checkCascadingSourcesRestrictions',
2550                                 'checkActionPermissions',
2551                                 'checkUserBlock'
2552                         ];
2553                 } else {
2554                         $checks = [
2555                                 'checkQuickPermissions',
2556                                 'checkPermissionHooks',
2557                                 'checkSpecialsAndNSPermissions',
2558                                 'checkCSSandJSPermissions',
2559                                 'checkPageRestrictions',
2560                                 'checkCascadingSourcesRestrictions',
2561                                 'checkActionPermissions',
2562                                 'checkUserBlock'
2563                         ];
2564                 }
2565
2566                 $errors = [];
2567                 while ( count( $checks ) > 0 &&
2568                                 !( $short && count( $errors ) > 0 ) ) {
2569                         $method = array_shift( $checks );
2570                         $errors = $this->$method( $action, $user, $errors, $rigor, $short );
2571                 }
2572
2573                 return $errors;
2574         }
2575
2576         /**
2577          * Get a filtered list of all restriction types supported by this wiki.
2578          * @param bool $exists True to get all restriction types that apply to
2579          * titles that do exist, False for all restriction types that apply to
2580          * titles that do not exist
2581          * @return array
2582          */
2583         public static function getFilteredRestrictionTypes( $exists = true ) {
2584                 global $wgRestrictionTypes;
2585                 $types = $wgRestrictionTypes;
2586                 if ( $exists ) {
2587                         # Remove the create restriction for existing titles
2588                         $types = array_diff( $types, [ 'create' ] );
2589                 } else {
2590                         # Only the create and upload restrictions apply to non-existing titles
2591                         $types = array_intersect( $types, [ 'create', 'upload' ] );
2592                 }
2593                 return $types;
2594         }
2595
2596         /**
2597          * Returns restriction types for the current Title
2598          *
2599          * @return array Applicable restriction types
2600          */
2601         public function getRestrictionTypes() {
2602                 if ( $this->isSpecialPage() ) {
2603                         return [];
2604                 }
2605
2606                 $types = self::getFilteredRestrictionTypes( $this->exists() );
2607
2608                 if ( $this->getNamespace() != NS_FILE ) {
2609                         # Remove the upload restriction for non-file titles
2610                         $types = array_diff( $types, [ 'upload' ] );
2611                 }
2612
2613                 Hooks::run( 'TitleGetRestrictionTypes', [ $this, &$types ] );
2614
2615                 wfDebug( __METHOD__ . ': applicable restrictions to [[' .
2616                         $this->getPrefixedText() . ']] are {' . implode( ',', $types ) . "}\n" );
2617
2618                 return $types;
2619         }
2620
2621         /**
2622          * Is this title subject to title protection?
2623          * Title protection is the one applied against creation of such title.
2624          *
2625          * @return array|bool An associative array representing any existent title
2626          *   protection, or false if there's none.
2627          */
2628         public function getTitleProtection() {
2629                 $protection = $this->getTitleProtectionInternal();
2630                 if ( $protection ) {
2631                         if ( $protection['permission'] == 'sysop' ) {
2632                                 $protection['permission'] = 'editprotected'; // B/C
2633                         }
2634                         if ( $protection['permission'] == 'autoconfirmed' ) {
2635                                 $protection['permission'] = 'editsemiprotected'; // B/C
2636                         }
2637                 }
2638                 return $protection;
2639         }
2640
2641         /**
2642          * Fetch title protection settings
2643          *
2644          * To work correctly, $this->loadRestrictions() needs to have access to the
2645          * actual protections in the database without munging 'sysop' =>
2646          * 'editprotected' and 'autoconfirmed' => 'editsemiprotected'. Other
2647          * callers probably want $this->getTitleProtection() instead.
2648          *
2649          * @return array|bool
2650          */
2651         protected function getTitleProtectionInternal() {
2652                 // Can't protect pages in special namespaces
2653                 if ( $this->getNamespace() < 0 ) {
2654                         return false;
2655                 }
2656
2657                 // Can't protect pages that exist.
2658                 if ( $this->exists() ) {
2659                         return false;
2660                 }
2661
2662                 if ( $this->mTitleProtection === null ) {
2663                         $dbr = wfGetDB( DB_REPLICA );
2664                         $res = $dbr->select(
2665                                 'protected_titles',
2666                                 [
2667                                         'user' => 'pt_user',
2668                                         'reason' => 'pt_reason',
2669                                         'expiry' => 'pt_expiry',
2670                                         'permission' => 'pt_create_perm'
2671                                 ],
2672                                 [ 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ],
2673                                 __METHOD__
2674                         );
2675
2676                         // fetchRow returns false if there are no rows.
2677                         $row = $dbr->fetchRow( $res );
2678                         if ( $row ) {
2679                                 $row['expiry'] = $dbr->decodeExpiry( $row['expiry'] );
2680                         }
2681                         $this->mTitleProtection = $row;
2682                 }
2683                 return $this->mTitleProtection;
2684         }
2685
2686         /**
2687          * Remove any title protection due to page existing
2688          */
2689         public function deleteTitleProtection() {
2690                 $dbw = wfGetDB( DB_MASTER );
2691
2692                 $dbw->delete(
2693                         'protected_titles',
2694                         [ 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ],
2695                         __METHOD__
2696                 );
2697                 $this->mTitleProtection = false;
2698         }
2699
2700         /**
2701          * Is this page "semi-protected" - the *only* protection levels are listed
2702          * in $wgSemiprotectedRestrictionLevels?
2703          *
2704          * @param string $action Action to check (default: edit)
2705          * @return bool
2706          */
2707         public function isSemiProtected( $action = 'edit' ) {
2708                 global $wgSemiprotectedRestrictionLevels;
2709
2710                 $restrictions = $this->getRestrictions( $action );
2711                 $semi = $wgSemiprotectedRestrictionLevels;
2712                 if ( !$restrictions || !$semi ) {
2713                         // Not protected, or all protection is full protection
2714                         return false;
2715                 }
2716
2717                 // Remap autoconfirmed to editsemiprotected for BC
2718                 foreach ( array_keys( $semi, 'autoconfirmed' ) as $key ) {
2719                         $semi[$key] = 'editsemiprotected';
2720                 }
2721                 foreach ( array_keys( $restrictions, 'autoconfirmed' ) as $key ) {
2722                         $restrictions[$key] = 'editsemiprotected';
2723                 }
2724
2725                 return !array_diff( $restrictions, $semi );
2726         }
2727
2728         /**
2729          * Does the title correspond to a protected article?
2730          *
2731          * @param string $action The action the page is protected from,
2732          * by default checks all actions.
2733          * @return bool
2734          */
2735         public function isProtected( $action = '' ) {
2736                 global $wgRestrictionLevels;
2737
2738                 $restrictionTypes = $this->getRestrictionTypes();
2739
2740                 # Special pages have inherent protection
2741                 if ( $this->isSpecialPage() ) {
2742                         return true;
2743                 }
2744
2745                 # Check regular protection levels
2746                 foreach ( $restrictionTypes as $type ) {
2747                         if ( $action == $type || $action == '' ) {
2748                                 $r = $this->getRestrictions( $type );
2749                                 foreach ( $wgRestrictionLevels as $level ) {
2750                                         if ( in_array( $level, $r ) && $level != '' ) {
2751                                                 return true;
2752                                         }
2753                                 }
2754                         }
2755                 }
2756
2757                 return false;
2758         }
2759
2760         /**
2761          * Determines if $user is unable to edit this page because it has been protected
2762          * by $wgNamespaceProtection.
2763          *
2764          * @param User $user User object to check permissions
2765          * @return bool
2766          */
2767         public function isNamespaceProtected( User $user ) {
2768                 global $wgNamespaceProtection;
2769
2770                 if ( isset( $wgNamespaceProtection[$this->mNamespace] ) ) {
2771                         foreach ( (array)$wgNamespaceProtection[$this->mNamespace] as $right ) {
2772                                 if ( $right != '' && !$user->isAllowed( $right ) ) {
2773                                         return true;
2774                                 }
2775                         }
2776                 }
2777                 return false;
2778         }
2779
2780         /**
2781          * Cascading protection: Return true if cascading restrictions apply to this page, false if not.
2782          *
2783          * @return bool If the page is subject to cascading restrictions.
2784          */
2785         public function isCascadeProtected() {
2786                 list( $sources, /* $restrictions */ ) = $this->getCascadeProtectionSources( false );
2787                 return ( $sources > 0 );
2788         }
2789
2790         /**
2791          * Determines whether cascading protection sources have already been loaded from
2792          * the database.
2793          *
2794          * @param bool $getPages True to check if the pages are loaded, or false to check
2795          * if the status is loaded.
2796          * @return bool Whether or not the specified information has been loaded
2797          * @since 1.23
2798          */
2799         public function areCascadeProtectionSourcesLoaded( $getPages = true ) {
2800                 return $getPages ? $this->mCascadeSources !== null : $this->mHasCascadingRestrictions !== null;
2801         }
2802
2803         /**
2804          * Cascading protection: Get the source of any cascading restrictions on this page.
2805          *
2806          * @param bool $getPages Whether or not to retrieve the actual pages
2807          *        that the restrictions have come from and the actual restrictions
2808          *        themselves.
2809          * @return array Two elements: First is an array of Title objects of the
2810          *        pages from which cascading restrictions have come, false for
2811          *        none, or true if such restrictions exist but $getPages was not
2812          *        set. Second is an array like that returned by
2813          *        Title::getAllRestrictions(), or an empty array if $getPages is
2814          *        false.
2815          */
2816         public function getCascadeProtectionSources( $getPages = true ) {
2817                 $pagerestrictions = [];
2818
2819                 if ( $this->mCascadeSources !== null && $getPages ) {
2820                         return [ $this->mCascadeSources, $this->mCascadingRestrictions ];
2821                 } elseif ( $this->mHasCascadingRestrictions !== null && !$getPages ) {
2822                         return [ $this->mHasCascadingRestrictions, $pagerestrictions ];
2823                 }
2824
2825                 $dbr = wfGetDB( DB_REPLICA );
2826
2827                 if ( $this->getNamespace() == NS_FILE ) {
2828                         $tables = [ 'imagelinks', 'page_restrictions' ];
2829                         $where_clauses = [
2830                                 'il_to' => $this->getDBkey(),
2831                                 'il_from=pr_page',
2832                                 'pr_cascade' => 1
2833                         ];
2834                 } else {
2835                         $tables = [ 'templatelinks', 'page_restrictions' ];
2836                         $where_clauses = [
2837                                 'tl_namespace' => $this->getNamespace(),
2838                                 'tl_title' => $this->getDBkey(),
2839                                 'tl_from=pr_page',
2840                                 'pr_cascade' => 1
2841                         ];
2842                 }
2843
2844                 if ( $getPages ) {
2845                         $cols = [ 'pr_page', 'page_namespace', 'page_title',
2846                                 'pr_expiry', 'pr_type', 'pr_level' ];
2847                         $where_clauses[] = 'page_id=pr_page';
2848                         $tables[] = 'page';
2849                 } else {
2850                         $cols = [ 'pr_expiry' ];
2851                 }
2852
2853                 $res = $dbr->select( $tables, $cols, $where_clauses, __METHOD__ );
2854
2855                 $sources = $getPages ? [] : false;
2856                 $now = wfTimestampNow();
2857
2858                 foreach ( $res as $row ) {
2859                         $expiry = $dbr->decodeExpiry( $row->pr_expiry );
2860                         if ( $expiry > $now ) {
2861                                 if ( $getPages ) {
2862                                         $page_id = $row->pr_page;
2863                                         $page_ns = $row->page_namespace;
2864                                         $page_title = $row->page_title;
2865                                         $sources[$page_id] = self::makeTitle( $page_ns, $page_title );
2866                                         # Add groups needed for each restriction type if its not already there
2867                                         # Make sure this restriction type still exists
2868
2869                                         if ( !isset( $pagerestrictions[$row->pr_type] ) ) {
2870                                                 $pagerestrictions[$row->pr_type] = [];
2871                                         }
2872
2873                                         if (
2874                                                 isset( $pagerestrictions[$row->pr_type] )
2875                                                 && !in_array( $row->pr_level, $pagerestrictions[$row->pr_type] )
2876                                         ) {
2877                                                 $pagerestrictions[$row->pr_type][] = $row->pr_level;
2878                                         }
2879                                 } else {
2880                                         $sources = true;
2881                                 }
2882                         }
2883                 }
2884
2885                 if ( $getPages ) {
2886                         $this->mCascadeSources = $sources;
2887                         $this->mCascadingRestrictions = $pagerestrictions;
2888                 } else {
2889                         $this->mHasCascadingRestrictions = $sources;
2890                 }
2891
2892                 return [ $sources, $pagerestrictions ];
2893         }
2894
2895         /**
2896          * Accessor for mRestrictionsLoaded
2897          *
2898          * @return bool Whether or not the page's restrictions have already been
2899          * loaded from the database
2900          * @since 1.23
2901          */
2902         public function areRestrictionsLoaded() {
2903                 return $this->mRestrictionsLoaded;
2904         }
2905
2906         /**
2907          * Accessor/initialisation for mRestrictions
2908          *
2909          * @param string $action Action that permission needs to be checked for
2910          * @return array Restriction levels needed to take the action. All levels are
2911          *     required. Note that restriction levels are normally user rights, but 'sysop'
2912          *     and 'autoconfirmed' are also allowed for backwards compatibility. These should
2913          *     be mapped to 'editprotected' and 'editsemiprotected' respectively.
2914          */
2915         public function getRestrictions( $action ) {
2916                 if ( !$this->mRestrictionsLoaded ) {
2917                         $this->loadRestrictions();
2918                 }
2919                 return isset( $this->mRestrictions[$action] )
2920                                 ? $this->mRestrictions[$action]
2921                                 : [];
2922         }
2923
2924         /**
2925          * Accessor/initialisation for mRestrictions
2926          *
2927          * @return array Keys are actions, values are arrays as returned by
2928          *     Title::getRestrictions()
2929          * @since 1.23
2930          */
2931         public function getAllRestrictions() {
2932                 if ( !$this->mRestrictionsLoaded ) {
2933                         $this->loadRestrictions();
2934                 }
2935                 return $this->mRestrictions;
2936         }
2937
2938         /**
2939          * Get the expiry time for the restriction against a given action
2940          *
2941          * @param string $action
2942          * @return string|bool 14-char timestamp, or 'infinity' if the page is protected forever
2943          *     or not protected at all, or false if the action is not recognised.
2944          */
2945         public function getRestrictionExpiry( $action ) {
2946                 if ( !$this->mRestrictionsLoaded ) {
2947                         $this->loadRestrictions();
2948                 }
2949                 return isset( $this->mRestrictionsExpiry[$action] ) ? $this->mRestrictionsExpiry[$action] : false;
2950         }
2951
2952         /**
2953          * Returns cascading restrictions for the current article
2954          *
2955          * @return bool
2956          */
2957         function areRestrictionsCascading() {
2958                 if ( !$this->mRestrictionsLoaded ) {
2959                         $this->loadRestrictions();
2960                 }
2961
2962                 return $this->mCascadeRestriction;
2963         }
2964
2965         /**
2966          * Compiles list of active page restrictions from both page table (pre 1.10)
2967          * and page_restrictions table for this existing page.
2968          * Public for usage by LiquidThreads.
2969          *
2970          * @param array $rows Array of db result objects
2971          * @param string $oldFashionedRestrictions Comma-separated list of page
2972          *   restrictions from page table (pre 1.10)
2973          */
2974         public function loadRestrictionsFromRows( $rows, $oldFashionedRestrictions = null ) {
2975                 $dbr = wfGetDB( DB_REPLICA );
2976
2977                 $restrictionTypes = $this->getRestrictionTypes();
2978
2979                 foreach ( $restrictionTypes as $type ) {
2980                         $this->mRestrictions[$type] = [];
2981                         $this->mRestrictionsExpiry[$type] = 'infinity';
2982                 }
2983
2984                 $this->mCascadeRestriction = false;
2985
2986                 # Backwards-compatibility: also load the restrictions from the page record (old format).
2987                 if ( $oldFashionedRestrictions !== null ) {
2988                         $this->mOldRestrictions = $oldFashionedRestrictions;
2989                 }
2990
2991                 if ( $this->mOldRestrictions === false ) {
2992                         $this->mOldRestrictions = $dbr->selectField( 'page', 'page_restrictions',
2993                                 [ 'page_id' => $this->getArticleID() ], __METHOD__ );
2994                 }
2995
2996                 if ( $this->mOldRestrictions != '' ) {
2997                         foreach ( explode( ':', trim( $this->mOldRestrictions ) ) as $restrict ) {
2998                                 $temp = explode( '=', trim( $restrict ) );
2999                                 if ( count( $temp ) == 1 ) {
3000                                         // old old format should be treated as edit/move restriction
3001                                         $this->mRestrictions['edit'] = explode( ',', trim( $temp[0] ) );
3002                                         $this->mRestrictions['move'] = explode( ',', trim( $temp[0] ) );
3003                                 } else {
3004                                         $restriction = trim( $temp[1] );
3005                                         if ( $restriction != '' ) { // some old entries are empty
3006                                                 $this->mRestrictions[$temp[0]] = explode( ',', $restriction );
3007                                         }
3008                                 }
3009                         }
3010                 }
3011
3012                 if ( count( $rows ) ) {
3013                         # Current system - load second to make them override.
3014                         $now = wfTimestampNow();
3015
3016                         # Cycle through all the restrictions.
3017                         foreach ( $rows as $row ) {
3018                                 // Don't take care of restrictions types that aren't allowed
3019                                 if ( !in_array( $row->pr_type, $restrictionTypes ) ) {
3020                                         continue;
3021                                 }
3022
3023                                 $expiry = $dbr->decodeExpiry( $row->pr_expiry );
3024
3025                                 // Only apply the restrictions if they haven't expired!
3026                                 if ( !$expiry || $expiry > $now ) {
3027                                         $this->mRestrictionsExpiry[$row->pr_type] = $expiry;
3028                                         $this->mRestrictions[$row->pr_type] = explode( ',', trim( $row->pr_level ) );
3029
3030                                         $this->mCascadeRestriction |= $row->pr_cascade;
3031                                 }
3032                         }
3033                 }
3034
3035                 $this->mRestrictionsLoaded = true;
3036         }
3037
3038         /**
3039          * Load restrictions from the page_restrictions table
3040          *
3041          * @param string $oldFashionedRestrictions Comma-separated list of page
3042          *   restrictions from page table (pre 1.10)
3043          */
3044         public function loadRestrictions( $oldFashionedRestrictions = null ) {
3045                 if ( $this->mRestrictionsLoaded ) {
3046                         return;
3047                 }
3048
3049                 $id = $this->getArticleID();
3050                 if ( $id ) {
3051                         $cache = ObjectCache::getMainWANInstance();
3052                         $rows = $cache->getWithSetCallback(
3053                                 // Page protections always leave a new null revision
3054                                 $cache->makeKey( 'page-restrictions', $id, $this->getLatestRevID() ),
3055                                 $cache::TTL_DAY,
3056                                 function ( $curValue, &$ttl, array &$setOpts ) {
3057                                         $dbr = wfGetDB( DB_REPLICA );
3058
3059                                         $setOpts += Database::getCacheSetOptions( $dbr );
3060
3061                                         return iterator_to_array(
3062                                                 $dbr->select(
3063                                                         'page_restrictions',
3064                                                         [ 'pr_type', 'pr_expiry', 'pr_level', 'pr_cascade' ],
3065                                                         [ 'pr_page' => $this->getArticleID() ],
3066                                                         __METHOD__
3067                                                 )
3068                                         );
3069                                 }
3070                         );
3071
3072                         $this->loadRestrictionsFromRows( $rows, $oldFashionedRestrictions );
3073                 } else {
3074                         $title_protection = $this->getTitleProtectionInternal();
3075
3076                         if ( $title_protection ) {
3077                                 $now = wfTimestampNow();
3078                                 $expiry = wfGetDB( DB_REPLICA )->decodeExpiry( $title_protection['expiry'] );
3079
3080                                 if ( !$expiry || $expiry > $now ) {
3081                                         // Apply the restrictions
3082                                         $this->mRestrictionsExpiry['create'] = $expiry;
3083                                         $this->mRestrictions['create'] =
3084                                                 explode( ',', trim( $title_protection['permission'] ) );
3085                                 } else { // Get rid of the old restrictions
3086                                         $this->mTitleProtection = false;
3087                                 }
3088                         } else {
3089                                 $this->mRestrictionsExpiry['create'] = 'infinity';
3090                         }
3091                         $this->mRestrictionsLoaded = true;
3092                 }
3093         }
3094
3095         /**
3096          * Flush the protection cache in this object and force reload from the database.
3097          * This is used when updating protection from WikiPage::doUpdateRestrictions().
3098          */
3099         public function flushRestrictions() {
3100                 $this->mRestrictionsLoaded = false;
3101                 $this->mTitleProtection = null;
3102         }
3103
3104         /**
3105          * Purge expired restrictions from the page_restrictions table
3106          *
3107          * This will purge no more than $wgUpdateRowsPerQuery page_restrictions rows
3108          */
3109         static function purgeExpiredRestrictions() {
3110                 if ( wfReadOnly() ) {
3111                         return;
3112                 }
3113
3114                 DeferredUpdates::addUpdate( new AtomicSectionUpdate(
3115                         wfGetDB( DB_MASTER ),
3116                         __METHOD__,
3117                         function ( IDatabase $dbw, $fname ) {
3118                                 $config = MediaWikiServices::getInstance()->getMainConfig();
3119                                 $ids = $dbw->selectFieldValues(
3120                                         'page_restrictions',
3121                                         'pr_id',
3122                                         [ 'pr_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ],
3123                                         $fname,
3124                                         [ 'LIMIT' => $config->get( 'UpdateRowsPerQuery' ) ] // T135470
3125                                 );
3126                                 if ( $ids ) {
3127                                         $dbw->delete( 'page_restrictions', [ 'pr_id' => $ids ], $fname );
3128                                 }
3129                         }
3130                 ) );
3131
3132                 DeferredUpdates::addUpdate( new AtomicSectionUpdate(
3133                         wfGetDB( DB_MASTER ),
3134                         __METHOD__,
3135                         function ( IDatabase $dbw, $fname ) {
3136                                 $dbw->delete(
3137                                         'protected_titles',
3138                                         [ 'pt_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ],
3139                                         $fname
3140                                 );
3141                         }
3142                 ) );
3143         }
3144
3145         /**
3146          * Does this have subpages?  (Warning, usually requires an extra DB query.)
3147          *
3148          * @return bool
3149          */
3150         public function hasSubpages() {
3151                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
3152                         # Duh
3153                         return false;
3154                 }
3155
3156                 # We dynamically add a member variable for the purpose of this method
3157                 # alone to cache the result.  There's no point in having it hanging
3158                 # around uninitialized in every Title object; therefore we only add it
3159                 # if needed and don't declare it statically.
3160                 if ( $this->mHasSubpages === null ) {
3161                         $this->mHasSubpages = false;
3162                         $subpages = $this->getSubpages( 1 );
3163                         if ( $subpages instanceof TitleArray ) {
3164                                 $this->mHasSubpages = (bool)$subpages->count();
3165                         }
3166                 }
3167
3168                 return $this->mHasSubpages;
3169         }
3170
3171         /**
3172          * Get all subpages of this page.
3173          *
3174          * @param int $limit Maximum number of subpages to fetch; -1 for no limit
3175          * @return TitleArray|array TitleArray, or empty array if this page's namespace
3176          *  doesn't allow subpages
3177          */
3178         public function getSubpages( $limit = -1 ) {
3179                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3180                         return [];
3181                 }
3182
3183                 $dbr = wfGetDB( DB_REPLICA );
3184                 $conds['page_namespace'] = $this->getNamespace();
3185                 $conds[] = 'page_title ' . $dbr->buildLike( $this->getDBkey() . '/', $dbr->anyString() );
3186                 $options = [];
3187                 if ( $limit > -1 ) {
3188                         $options['LIMIT'] = $limit;
3189                 }
3190                 return TitleArray::newFromResult(
3191                         $dbr->select( 'page',
3192                                 [ 'page_id', 'page_namespace', 'page_title', 'page_is_redirect' ],
3193                                 $conds,
3194                                 __METHOD__,
3195                                 $options
3196                         )
3197                 );
3198         }
3199
3200         /**
3201          * Is there a version of this page in the deletion archive?
3202          *
3203          * @return int The number of archived revisions
3204          */
3205         public function isDeleted() {
3206                 if ( $this->getNamespace() < 0 ) {
3207                         $n = 0;
3208                 } else {
3209                         $dbr = wfGetDB( DB_REPLICA );
3210
3211                         $n = $dbr->selectField( 'archive', 'COUNT(*)',
3212                                 [ 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ],
3213                                 __METHOD__
3214                         );
3215                         if ( $this->getNamespace() == NS_FILE ) {
3216                                 $n += $dbr->selectField( 'filearchive', 'COUNT(*)',
3217                                         [ 'fa_name' => $this->getDBkey() ],
3218                                         __METHOD__
3219                                 );
3220                         }
3221                 }
3222                 return (int)$n;
3223         }
3224
3225         /**
3226          * Is there a version of this page in the deletion archive?
3227          *
3228          * @return bool
3229          */
3230         public function isDeletedQuick() {
3231                 if ( $this->getNamespace() < 0 ) {
3232                         return false;
3233                 }
3234                 $dbr = wfGetDB( DB_REPLICA );
3235                 $deleted = (bool)$dbr->selectField( 'archive', '1',
3236                         [ 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ],
3237                         __METHOD__
3238                 );
3239                 if ( !$deleted && $this->getNamespace() == NS_FILE ) {
3240                         $deleted = (bool)$dbr->selectField( 'filearchive', '1',
3241                                 [ 'fa_name' => $this->getDBkey() ],
3242                                 __METHOD__
3243                         );
3244                 }
3245                 return $deleted;
3246         }
3247
3248         /**
3249          * Get the article ID for this Title from the link cache,
3250          * adding it if necessary
3251          *
3252          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select
3253          *  for update
3254          * @return int The ID
3255          */
3256         public function getArticleID( $flags = 0 ) {
3257                 if ( $this->getNamespace() < 0 ) {
3258                         $this->mArticleID = 0;
3259                         return $this->mArticleID;
3260                 }
3261                 $linkCache = LinkCache::singleton();
3262                 if ( $flags & self::GAID_FOR_UPDATE ) {
3263                         $oldUpdate = $linkCache->forUpdate( true );
3264                         $linkCache->clearLink( $this );
3265                         $this->mArticleID = $linkCache->addLinkObj( $this );
3266                         $linkCache->forUpdate( $oldUpdate );
3267                 } else {
3268                         if ( -1 == $this->mArticleID ) {
3269                                 $this->mArticleID = $linkCache->addLinkObj( $this );
3270                         }
3271                 }
3272                 return $this->mArticleID;
3273         }
3274
3275         /**
3276          * Is this an article that is a redirect page?
3277          * Uses link cache, adding it if necessary
3278          *
3279          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3280          * @return bool
3281          */
3282         public function isRedirect( $flags = 0 ) {
3283                 if ( !is_null( $this->mRedirect ) ) {
3284                         return $this->mRedirect;
3285                 }
3286                 if ( !$this->getArticleID( $flags ) ) {
3287                         $this->mRedirect = false;
3288                         return $this->mRedirect;
3289                 }
3290
3291                 $linkCache = LinkCache::singleton();
3292                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3293                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'redirect' );
3294                 if ( $cached === null ) {
3295                         # Trust LinkCache's state over our own
3296                         # LinkCache is telling us that the page doesn't exist, despite there being cached
3297                         # data relating to an existing page in $this->mArticleID. Updaters should clear
3298                         # LinkCache as appropriate, or use $flags = Title::GAID_FOR_UPDATE. If that flag is
3299                         # set, then LinkCache will definitely be up to date here, since getArticleID() forces
3300                         # LinkCache to refresh its data from the master.
3301                         $this->mRedirect = false;
3302                         return $this->mRedirect;
3303                 }
3304
3305                 $this->mRedirect = (bool)$cached;
3306
3307                 return $this->mRedirect;
3308         }
3309
3310         /**
3311          * What is the length of this page?
3312          * Uses link cache, adding it if necessary
3313          *
3314          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3315          * @return int
3316          */
3317         public function getLength( $flags = 0 ) {
3318                 if ( $this->mLength != -1 ) {
3319                         return $this->mLength;
3320                 }
3321                 if ( !$this->getArticleID( $flags ) ) {
3322                         $this->mLength = 0;
3323                         return $this->mLength;
3324                 }
3325                 $linkCache = LinkCache::singleton();
3326                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3327                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'length' );
3328                 if ( $cached === null ) {
3329                         # Trust LinkCache's state over our own, as for isRedirect()
3330                         $this->mLength = 0;
3331                         return $this->mLength;
3332                 }
3333
3334                 $this->mLength = intval( $cached );
3335
3336                 return $this->mLength;
3337         }
3338
3339         /**
3340          * What is the page_latest field for this page?
3341          *
3342          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3343          * @return int Int or 0 if the page doesn't exist
3344          */
3345         public function getLatestRevID( $flags = 0 ) {
3346                 if ( !( $flags & self::GAID_FOR_UPDATE ) && $this->mLatestID !== false ) {
3347                         return intval( $this->mLatestID );
3348                 }
3349                 if ( !$this->getArticleID( $flags ) ) {
3350                         $this->mLatestID = 0;
3351                         return $this->mLatestID;
3352                 }
3353                 $linkCache = LinkCache::singleton();
3354                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3355                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'revision' );
3356                 if ( $cached === null ) {
3357                         # Trust LinkCache's state over our own, as for isRedirect()
3358                         $this->mLatestID = 0;
3359                         return $this->mLatestID;
3360                 }
3361
3362                 $this->mLatestID = intval( $cached );
3363
3364                 return $this->mLatestID;
3365         }
3366
3367         /**
3368          * This clears some fields in this object, and clears any associated
3369          * keys in the "bad links" section of the link cache.
3370          *
3371          * - This is called from WikiPage::doEditContent() and WikiPage::insertOn() to allow
3372          * loading of the new page_id. It's also called from
3373          * WikiPage::doDeleteArticleReal()
3374          *
3375          * @param int $newid The new Article ID
3376          */
3377         public function resetArticleID( $newid ) {
3378                 $linkCache = LinkCache::singleton();
3379                 $linkCache->clearLink( $this );
3380
3381                 if ( $newid === false ) {
3382                         $this->mArticleID = -1;
3383                 } else {
3384                         $this->mArticleID = intval( $newid );
3385                 }
3386                 $this->mRestrictionsLoaded = false;
3387                 $this->mRestrictions = [];
3388                 $this->mOldRestrictions = false;
3389                 $this->mRedirect = null;
3390                 $this->mLength = -1;
3391                 $this->mLatestID = false;
3392                 $this->mContentModel = false;
3393                 $this->mEstimateRevisions = null;
3394                 $this->mPageLanguage = false;
3395                 $this->mDbPageLanguage = false;
3396                 $this->mIsBigDeletion = null;
3397         }
3398
3399         public static function clearCaches() {
3400                 $linkCache = LinkCache::singleton();
3401                 $linkCache->clear();
3402
3403                 $titleCache = self::getTitleCache();
3404                 $titleCache->clear();
3405         }
3406
3407         /**
3408          * Capitalize a text string for a title if it belongs to a namespace that capitalizes
3409          *
3410          * @param string $text Containing title to capitalize
3411          * @param int $ns Namespace index, defaults to NS_MAIN
3412          * @return string Containing capitalized title
3413          */
3414         public static function capitalize( $text, $ns = NS_MAIN ) {
3415                 global $wgContLang;
3416
3417                 if ( MWNamespace::isCapitalized( $ns ) ) {
3418                         return $wgContLang->ucfirst( $text );
3419                 } else {
3420                         return $text;
3421                 }
3422         }
3423
3424         /**
3425          * Secure and split - main initialisation function for this object
3426          *
3427          * Assumes that mDbkeyform has been set, and is urldecoded
3428          * and uses underscores, but not otherwise munged.  This function
3429          * removes illegal characters, splits off the interwiki and
3430          * namespace prefixes, sets the other forms, and canonicalizes
3431          * everything.
3432          *
3433          * @throws MalformedTitleException On invalid titles
3434          * @return bool True on success
3435          */
3436         private function secureAndSplit() {
3437                 # Initialisation
3438                 $this->mInterwiki = '';
3439                 $this->mFragment = '';
3440                 $this->mNamespace = $this->mDefaultNamespace; # Usually NS_MAIN
3441
3442                 $dbkey = $this->mDbkeyform;
3443
3444                 // @note: splitTitleString() is a temporary hack to allow MediaWikiTitleCodec to share
3445                 //        the parsing code with Title, while avoiding massive refactoring.
3446                 // @todo: get rid of secureAndSplit, refactor parsing code.
3447                 // @note: getTitleParser() returns a TitleParser implementation which does not have a
3448                 //        splitTitleString method, but the only implementation (MediaWikiTitleCodec) does
3449                 $titleCodec = MediaWikiServices::getInstance()->getTitleParser();
3450                 // MalformedTitleException can be thrown here
3451                 $parts = $titleCodec->splitTitleString( $dbkey, $this->getDefaultNamespace() );
3452
3453                 # Fill fields
3454                 $this->setFragment( '#' . $parts['fragment'] );
3455                 $this->mInterwiki = $parts['interwiki'];
3456                 $this->mLocalInterwiki = $parts['local_interwiki'];
3457                 $this->mNamespace = $parts['namespace'];
3458                 $this->mUserCaseDBKey = $parts['user_case_dbkey'];
3459
3460                 $this->mDbkeyform = $parts['dbkey'];
3461                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
3462                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
3463
3464                 # We already know that some pages won't be in the database!
3465                 if ( $this->isExternal() || $this->isSpecialPage() ) {
3466                         $this->mArticleID = 0;
3467                 }
3468
3469                 return true;
3470         }
3471
3472         /**
3473          * Get an array of Title objects linking to this Title
3474          * Also stores the IDs in the link cache.
3475          *
3476          * WARNING: do not use this function on arbitrary user-supplied titles!
3477          * On heavily-used templates it will max out the memory.
3478          *
3479          * @param array $options May be FOR UPDATE
3480          * @param string $table Table name
3481          * @param string $prefix Fields prefix
3482          * @return Title[] Array of Title objects linking here
3483          */
3484         public function getLinksTo( $options = [], $table = 'pagelinks', $prefix = 'pl' ) {
3485                 if ( count( $options ) > 0 ) {
3486                         $db = wfGetDB( DB_MASTER );
3487                 } else {
3488                         $db = wfGetDB( DB_REPLICA );
3489                 }
3490
3491                 $res = $db->select(
3492                         [ 'page', $table ],
3493                         self::getSelectFields(),
3494                         [
3495                                 "{$prefix}_from=page_id",
3496                                 "{$prefix}_namespace" => $this->getNamespace(),
3497                                 "{$prefix}_title" => $this->getDBkey() ],
3498                         __METHOD__,
3499                         $options
3500                 );
3501
3502                 $retVal = [];
3503                 if ( $res->numRows() ) {
3504                         $linkCache = LinkCache::singleton();
3505                         foreach ( $res as $row ) {
3506                                 $titleObj = self::makeTitle( $row->page_namespace, $row->page_title );
3507                                 if ( $titleObj ) {
3508                                         $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3509                                         $retVal[] = $titleObj;
3510                                 }
3511                         }
3512                 }
3513                 return $retVal;
3514         }
3515
3516         /**
3517          * Get an array of Title objects using this Title as a template
3518          * Also stores the IDs in the link cache.
3519          *
3520          * WARNING: do not use this function on arbitrary user-supplied titles!
3521          * On heavily-used templates it will max out the memory.
3522          *
3523          * @param array $options Query option to Database::select()
3524          * @return Title[] Array of Title the Title objects linking here
3525          */
3526         public function getTemplateLinksTo( $options = [] ) {
3527                 return $this->getLinksTo( $options, 'templatelinks', 'tl' );
3528         }
3529
3530         /**
3531          * Get an array of Title objects linked from this Title
3532          * Also stores the IDs in the link cache.
3533          *
3534          * WARNING: do not use this function on arbitrary user-supplied titles!
3535          * On heavily-used templates it will max out the memory.
3536          *
3537          * @param array $options Query option to Database::select()
3538          * @param string $table Table name
3539          * @param string $prefix Fields prefix
3540          * @return array Array of Title objects linking here
3541          */
3542         public function getLinksFrom( $options = [], $table = 'pagelinks', $prefix = 'pl' ) {
3543                 $id = $this->getArticleID();
3544
3545                 # If the page doesn't exist; there can't be any link from this page
3546                 if ( !$id ) {
3547                         return [];
3548                 }
3549
3550                 $db = wfGetDB( DB_REPLICA );
3551
3552                 $blNamespace = "{$prefix}_namespace";
3553                 $blTitle = "{$prefix}_title";
3554
3555                 $res = $db->select(
3556                         [ $table, 'page' ],
3557                         array_merge(
3558                                 [ $blNamespace, $blTitle ],
3559                                 WikiPage::selectFields()
3560                         ),
3561                         [ "{$prefix}_from" => $id ],
3562                         __METHOD__,
3563                         $options,
3564                         [ 'page' => [
3565                                 'LEFT JOIN',
3566                                 [ "page_namespace=$blNamespace", "page_title=$blTitle" ]
3567                         ] ]
3568                 );
3569
3570                 $retVal = [];
3571                 $linkCache = LinkCache::singleton();
3572                 foreach ( $res as $row ) {
3573                         if ( $row->page_id ) {
3574                                 $titleObj = self::newFromRow( $row );
3575                         } else {
3576                                 $titleObj = self::makeTitle( $row->$blNamespace, $row->$blTitle );
3577                                 $linkCache->addBadLinkObj( $titleObj );
3578                         }
3579                         $retVal[] = $titleObj;
3580                 }
3581
3582                 return $retVal;
3583         }
3584
3585         /**
3586          * Get an array of Title objects used on this Title as a template
3587          * Also stores the IDs in the link cache.
3588          *
3589          * WARNING: do not use this function on arbitrary user-supplied titles!
3590          * On heavily-used templates it will max out the memory.
3591          *
3592          * @param array $options May be FOR UPDATE
3593          * @return Title[] Array of Title the Title objects used here
3594          */
3595         public function getTemplateLinksFrom( $options = [] ) {
3596                 return $this->getLinksFrom( $options, 'templatelinks', 'tl' );
3597         }
3598
3599         /**
3600          * Get an array of Title objects referring to non-existent articles linked
3601          * from this page.
3602          *
3603          * @todo check if needed (used only in SpecialBrokenRedirects.php, and
3604          *   should use redirect table in this case).
3605          * @return Title[] Array of Title the Title objects
3606          */
3607         public function getBrokenLinksFrom() {
3608                 if ( $this->getArticleID() == 0 ) {
3609                         # All links from article ID 0 are false positives
3610                         return [];
3611                 }
3612
3613                 $dbr = wfGetDB( DB_REPLICA );
3614                 $res = $dbr->select(
3615                         [ 'page', 'pagelinks' ],
3616                         [ 'pl_namespace', 'pl_title' ],
3617                         [
3618                                 'pl_from' => $this->getArticleID(),
3619                                 'page_namespace IS NULL'
3620                         ],
3621                         __METHOD__, [],
3622                         [
3623                                 'page' => [
3624                                         'LEFT JOIN',
3625                                         [ 'pl_namespace=page_namespace', 'pl_title=page_title' ]
3626                                 ]
3627                         ]
3628                 );
3629
3630                 $retVal = [];
3631                 foreach ( $res as $row ) {
3632                         $retVal[] = self::makeTitle( $row->pl_namespace, $row->pl_title );
3633                 }
3634                 return $retVal;
3635         }
3636
3637         /**
3638          * Get a list of URLs to purge from the CDN cache when this
3639          * page changes
3640          *
3641          * @return string[] Array of String the URLs
3642          */
3643         public function getCdnUrls() {
3644                 $urls = [
3645                         $this->getInternalURL(),
3646                         $this->getInternalURL( 'action=history' )
3647                 ];
3648
3649                 $pageLang = $this->getPageLanguage();
3650                 if ( $pageLang->hasVariants() ) {
3651                         $variants = $pageLang->getVariants();
3652                         foreach ( $variants as $vCode ) {
3653                                 $urls[] = $this->getInternalURL( $vCode );
3654                         }
3655                 }
3656
3657                 // If we are looking at a css/js user subpage, purge the action=raw.
3658                 if ( $this->isJsSubpage() ) {
3659                         $urls[] = $this->getInternalURL( 'action=raw&ctype=text/javascript' );
3660                 } elseif ( $this->isCssSubpage() ) {
3661                         $urls[] = $this->getInternalURL( 'action=raw&ctype=text/css' );
3662                 }
3663
3664                 Hooks::run( 'TitleSquidURLs', [ $this, &$urls ] );
3665                 return $urls;
3666         }
3667
3668         /**
3669          * @deprecated since 1.27 use getCdnUrls()
3670          */
3671         public function getSquidURLs() {
3672                 return $this->getCdnUrls();
3673         }
3674
3675         /**
3676          * Purge all applicable CDN URLs
3677          */
3678         public function purgeSquid() {
3679                 DeferredUpdates::addUpdate(
3680                         new CdnCacheUpdate( $this->getCdnUrls() ),
3681                         DeferredUpdates::PRESEND
3682                 );
3683         }
3684
3685         /**
3686          * Check whether a given move operation would be valid.
3687          * Returns true if ok, or a getUserPermissionsErrors()-like array otherwise
3688          *
3689          * @deprecated since 1.25, use MovePage's methods instead
3690          * @param Title $nt The new title
3691          * @param bool $auth Whether to check user permissions (uses $wgUser)
3692          * @param string $reason Is the log summary of the move, used for spam checking
3693          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3694          */
3695         public function isValidMoveOperation( &$nt, $auth = true, $reason = '' ) {
3696                 global $wgUser;
3697
3698                 if ( !( $nt instanceof Title ) ) {
3699                         // Normally we'd add this to $errors, but we'll get
3700                         // lots of syntax errors if $nt is not an object
3701                         return [ [ 'badtitletext' ] ];
3702                 }
3703
3704                 $mp = new MovePage( $this, $nt );
3705                 $errors = $mp->isValidMove()->getErrorsArray();
3706                 if ( $auth ) {
3707                         $errors = wfMergeErrorArrays(
3708                                 $errors,
3709                                 $mp->checkPermissions( $wgUser, $reason )->getErrorsArray()
3710                         );
3711                 }
3712
3713                 return $errors ?: true;
3714         }
3715
3716         /**
3717          * Check if the requested move target is a valid file move target
3718          * @todo move this to MovePage
3719          * @param Title $nt Target title
3720          * @return array List of errors
3721          */
3722         protected function validateFileMoveOperation( $nt ) {
3723                 global $wgUser;
3724
3725                 $errors = [];
3726
3727                 $destFile = wfLocalFile( $nt );
3728                 $destFile->load( File::READ_LATEST );
3729                 if ( !$wgUser->isAllowed( 'reupload-shared' )
3730                         && !$destFile->exists() && wfFindFile( $nt )
3731                 ) {
3732                         $errors[] = [ 'file-exists-sharedrepo' ];
3733                 }
3734
3735                 return $errors;
3736         }
3737
3738         /**
3739          * Move a title to a new location
3740          *
3741          * @deprecated since 1.25, use the MovePage class instead
3742          * @param Title $nt The new title
3743          * @param bool $auth Indicates whether $wgUser's permissions
3744          *  should be checked
3745          * @param string $reason The reason for the move
3746          * @param bool $createRedirect Whether to create a redirect from the old title to the new title.
3747          *  Ignored if the user doesn't have the suppressredirect right.
3748          * @param array $changeTags Applied to the entry in the move log and redirect page revision
3749          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3750          */
3751         public function moveTo( &$nt, $auth = true, $reason = '', $createRedirect = true,
3752                 array $changeTags = []
3753         ) {
3754                 global $wgUser;
3755                 $err = $this->isValidMoveOperation( $nt, $auth, $reason );
3756                 if ( is_array( $err ) ) {
3757                         // Auto-block user's IP if the account was "hard" blocked
3758                         $wgUser->spreadAnyEditBlock();
3759                         return $err;
3760                 }
3761                 // Check suppressredirect permission
3762                 if ( $auth && !$wgUser->isAllowed( 'suppressredirect' ) ) {
3763                         $createRedirect = true;
3764                 }
3765
3766                 $mp = new MovePage( $this, $nt );
3767                 $status = $mp->move( $wgUser, $reason, $createRedirect, $changeTags );
3768                 if ( $status->isOK() ) {
3769                         return true;
3770                 } else {
3771                         return $status->getErrorsArray();
3772                 }
3773         }
3774
3775         /**
3776          * Move this page's subpages to be subpages of $nt
3777          *
3778          * @param Title $nt Move target
3779          * @param bool $auth Whether $wgUser's permissions should be checked
3780          * @param string $reason The reason for the move
3781          * @param bool $createRedirect Whether to create redirects from the old subpages to
3782          *     the new ones Ignored if the user doesn't have the 'suppressredirect' right
3783          * @param array $changeTags Applied to the entry in the move log and redirect page revision
3784          * @return array Array with old page titles as keys, and strings (new page titles) or
3785          *     getUserPermissionsErrors()-like arrays (errors) as values, or a
3786          *     getUserPermissionsErrors()-like error array with numeric indices if
3787          *     no pages were moved
3788          */
3789         public function moveSubpages( $nt, $auth = true, $reason = '', $createRedirect = true,
3790                 array $changeTags = []
3791         ) {
3792                 global $wgMaximumMovedPages;
3793                 // Check permissions
3794                 if ( !$this->userCan( 'move-subpages' ) ) {
3795                         return [
3796                                 [ 'cant-move-subpages' ],
3797                         ];
3798                 }
3799                 // Do the source and target namespaces support subpages?
3800                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3801                         return [
3802                                 [ 'namespace-nosubpages', MWNamespace::getCanonicalName( $this->getNamespace() ) ],
3803                         ];
3804                 }
3805                 if ( !MWNamespace::hasSubpages( $nt->getNamespace() ) ) {
3806                         return [
3807                                 [ 'namespace-nosubpages', MWNamespace::getCanonicalName( $nt->getNamespace() ) ],
3808                         ];
3809                 }
3810
3811                 $subpages = $this->getSubpages( $wgMaximumMovedPages + 1 );
3812                 $retval = [];
3813                 $count = 0;
3814                 foreach ( $subpages as $oldSubpage ) {
3815                         $count++;
3816                         if ( $count > $wgMaximumMovedPages ) {
3817                                 $retval[$oldSubpage->getPrefixedText()] = [
3818                                         [ 'movepage-max-pages', $wgMaximumMovedPages ],
3819                                 ];
3820                                 break;
3821                         }
3822
3823                         // We don't know whether this function was called before
3824                         // or after moving the root page, so check both
3825                         // $this and $nt
3826                         if ( $oldSubpage->getArticleID() == $this->getArticleID()
3827                                 || $oldSubpage->getArticleID() == $nt->getArticleID()
3828                         ) {
3829                                 // When moving a page to a subpage of itself,
3830                                 // don't move it twice
3831                                 continue;
3832                         }
3833                         $newPageName = preg_replace(
3834                                         '#^' . preg_quote( $this->getDBkey(), '#' ) . '#',
3835                                         StringUtils::escapeRegexReplacement( $nt->getDBkey() ), # T23234
3836                                         $oldSubpage->getDBkey() );
3837                         if ( $oldSubpage->isTalkPage() ) {
3838                                 $newNs = $nt->getTalkPage()->getNamespace();
3839                         } else {
3840                                 $newNs = $nt->getSubjectPage()->getNamespace();
3841                         }
3842                         # T16385: we need makeTitleSafe because the new page names may
3843                         # be longer than 255 characters.
3844                         $newSubpage = self::makeTitleSafe( $newNs, $newPageName );
3845
3846                         $success = $oldSubpage->moveTo( $newSubpage, $auth, $reason, $createRedirect, $changeTags );
3847                         if ( $success === true ) {
3848                                 $retval[$oldSubpage->getPrefixedText()] = $newSubpage->getPrefixedText();
3849                         } else {
3850                                 $retval[$oldSubpage->getPrefixedText()] = $success;
3851                         }
3852                 }
3853                 return $retval;
3854         }
3855
3856         /**
3857          * Checks if this page is just a one-rev redirect.
3858          * Adds lock, so don't use just for light purposes.
3859          *
3860          * @return bool
3861          */
3862         public function isSingleRevRedirect() {
3863                 global $wgContentHandlerUseDB;
3864
3865                 $dbw = wfGetDB( DB_MASTER );
3866
3867                 # Is it a redirect?
3868                 $fields = [ 'page_is_redirect', 'page_latest', 'page_id' ];
3869                 if ( $wgContentHandlerUseDB ) {
3870                         $fields[] = 'page_content_model';
3871                 }
3872
3873                 $row = $dbw->selectRow( 'page',
3874                         $fields,
3875                         $this->pageCond(),
3876                         __METHOD__,
3877                         [ 'FOR UPDATE' ]
3878                 );
3879                 # Cache some fields we may want
3880                 $this->mArticleID = $row ? intval( $row->page_id ) : 0;
3881                 $this->mRedirect = $row ? (bool)$row->page_is_redirect : false;
3882                 $this->mLatestID = $row ? intval( $row->page_latest ) : false;
3883                 $this->mContentModel = $row && isset( $row->page_content_model )
3884                         ? strval( $row->page_content_model )
3885                         : false;
3886
3887                 if ( !$this->mRedirect ) {
3888                         return false;
3889                 }
3890                 # Does the article have a history?
3891                 $row = $dbw->selectField( [ 'page', 'revision' ],
3892                         'rev_id',
3893                         [ 'page_namespace' => $this->getNamespace(),
3894                                 'page_title' => $this->getDBkey(),
3895                                 'page_id=rev_page',
3896                                 'page_latest != rev_id'
3897                         ],
3898                         __METHOD__,
3899                         [ 'FOR UPDATE' ]
3900                 );
3901                 # Return true if there was no history
3902                 return ( $row === false );
3903         }
3904
3905         /**
3906          * Checks if $this can be moved to a given Title
3907          * - Selects for update, so don't call it unless you mean business
3908          *
3909          * @deprecated since 1.25, use MovePage's methods instead
3910          * @param Title $nt The new title to check
3911          * @return bool
3912          */
3913         public function isValidMoveTarget( $nt ) {
3914                 # Is it an existing file?
3915                 if ( $nt->getNamespace() == NS_FILE ) {
3916                         $file = wfLocalFile( $nt );
3917                         $file->load( File::READ_LATEST );
3918                         if ( $file->exists() ) {
3919                                 wfDebug( __METHOD__ . ": file exists\n" );
3920                                 return false;
3921                         }
3922                 }
3923                 # Is it a redirect with no history?
3924                 if ( !$nt->isSingleRevRedirect() ) {
3925                         wfDebug( __METHOD__ . ": not a one-rev redirect\n" );
3926                         return false;
3927                 }
3928                 # Get the article text
3929                 $rev = Revision::newFromTitle( $nt, false, Revision::READ_LATEST );
3930                 if ( !is_object( $rev ) ) {
3931                         return false;
3932                 }
3933                 $content = $rev->getContent();
3934                 # Does the redirect point to the source?
3935                 # Or is it a broken self-redirect, usually caused by namespace collisions?
3936                 $redirTitle = $content ? $content->getRedirectTarget() : null;
3937
3938                 if ( $redirTitle ) {
3939                         if ( $redirTitle->getPrefixedDBkey() != $this->getPrefixedDBkey() &&
3940                                 $redirTitle->getPrefixedDBkey() != $nt->getPrefixedDBkey() ) {
3941                                 wfDebug( __METHOD__ . ": redirect points to other page\n" );
3942                                 return false;
3943                         } else {
3944                                 return true;
3945                         }
3946                 } else {
3947                         # Fail safe (not a redirect after all. strange.)
3948                         wfDebug( __METHOD__ . ": failsafe: database sais " . $nt->getPrefixedDBkey() .
3949                                                 " is a redirect, but it doesn't contain a valid redirect.\n" );
3950                         return false;
3951                 }
3952         }
3953
3954         /**
3955          * Get categories to which this Title belongs and return an array of
3956          * categories' names.
3957          *
3958          * @return array Array of parents in the form:
3959          *     $parent => $currentarticle
3960          */
3961         public function getParentCategories() {
3962                 global $wgContLang;
3963
3964                 $data = [];
3965
3966                 $titleKey = $this->getArticleID();
3967
3968                 if ( $titleKey === 0 ) {
3969                         return $data;
3970                 }
3971
3972                 $dbr = wfGetDB( DB_REPLICA );
3973
3974                 $res = $dbr->select(
3975                         'categorylinks',
3976                         'cl_to',
3977                         [ 'cl_from' => $titleKey ],
3978                         __METHOD__
3979                 );
3980
3981                 if ( $res->numRows() > 0 ) {
3982                         foreach ( $res as $row ) {
3983                                 // $data[] = Title::newFromText($wgContLang->getNsText ( NS_CATEGORY ).':'.$row->cl_to);
3984                                 $data[$wgContLang->getNsText( NS_CATEGORY ) . ':' . $row->cl_to] = $this->getFullText();
3985                         }
3986                 }
3987                 return $data;
3988         }
3989
3990         /**
3991          * Get a tree of parent categories
3992          *
3993          * @param array $children Array with the children in the keys, to check for circular refs
3994          * @return array Tree of parent categories
3995          */
3996         public function getParentCategoryTree( $children = [] ) {
3997                 $stack = [];
3998                 $parents = $this->getParentCategories();
3999
4000                 if ( $parents ) {
4001                         foreach ( $parents as $parent => $current ) {
4002                                 if ( array_key_exists( $parent, $children ) ) {
4003                                         # Circular reference
4004                                         $stack[$parent] = [];
4005                                 } else {
4006                                         $nt = self::newFromText( $parent );
4007                                         if ( $nt ) {
4008                                                 $stack[$parent] = $nt->getParentCategoryTree( $children + [ $parent => 1 ] );
4009                                         }
4010                                 }
4011                         }
4012                 }
4013
4014                 return $stack;
4015         }
4016
4017         /**
4018          * Get an associative array for selecting this title from
4019          * the "page" table
4020          *
4021          * @return array Array suitable for the $where parameter of DB::select()
4022          */
4023         public function pageCond() {
4024                 if ( $this->mArticleID > 0 ) {
4025                         // PK avoids secondary lookups in InnoDB, shouldn't hurt other DBs
4026                         return [ 'page_id' => $this->mArticleID ];
4027                 } else {
4028                         return [ 'page_namespace' => $this->mNamespace, 'page_title' => $this->mDbkeyform ];
4029                 }
4030         }
4031
4032         /**
4033          * Get next/previous revision ID relative to another revision ID
4034          * @param int $revId Revision ID. Get the revision that was before this one.
4035          * @param int $flags Title::GAID_FOR_UPDATE
4036          * @param string $dir 'next' or 'prev'
4037          * @return int|bool New revision ID, or false if none exists
4038          */
4039         private function getRelativeRevisionID( $revId, $flags, $dir ) {
4040                 $revId = (int)$revId;
4041                 if ( $dir === 'next' ) {
4042                         $op = '>';
4043                         $sort = 'ASC';
4044                 } elseif ( $dir === 'prev' ) {
4045                         $op = '<';
4046                         $sort = 'DESC';
4047                 } else {
4048                         throw new InvalidArgumentException( '$dir must be "next" or "prev"' );
4049                 }
4050
4051                 if ( $flags & self::GAID_FOR_UPDATE ) {
4052                         $db = wfGetDB( DB_MASTER );
4053                 } else {
4054                         $db = wfGetDB( DB_REPLICA, 'contributions' );
4055                 }
4056
4057                 // Intentionally not caring if the specified revision belongs to this
4058                 // page. We only care about the timestamp.
4059                 $ts = $db->selectField( 'revision', 'rev_timestamp', [ 'rev_id' => $revId ], __METHOD__ );
4060                 if ( $ts === false ) {
4061                         $ts = $db->selectField( 'archive', 'ar_timestamp', [ 'ar_rev_id' => $revId ], __METHOD__ );
4062                         if ( $ts === false ) {
4063                                 // Or should this throw an InvalidArgumentException or something?
4064                                 return false;
4065                         }
4066                 }
4067                 $ts = $db->addQuotes( $ts );
4068
4069                 $revId = $db->selectField( 'revision', 'rev_id',
4070                         [
4071                                 'rev_page' => $this->getArticleID( $flags ),
4072                                 "rev_timestamp $op $ts OR (rev_timestamp = $ts AND rev_id $op $revId)"
4073                         ],
4074                         __METHOD__,
4075                         [
4076                                 'ORDER BY' => "rev_timestamp $sort, rev_id $sort",
4077                                 'IGNORE INDEX' => 'rev_timestamp', // Probably needed for T159319
4078                         ]
4079                 );
4080
4081                 if ( $revId === false ) {
4082                         return false;
4083                 } else {
4084                         return intval( $revId );
4085                 }
4086         }
4087
4088         /**
4089          * Get the revision ID of the previous revision
4090          *
4091          * @param int $revId Revision ID. Get the revision that was before this one.
4092          * @param int $flags Title::GAID_FOR_UPDATE
4093          * @return int|bool Old revision ID, or false if none exists
4094          */
4095         public function getPreviousRevisionID( $revId, $flags = 0 ) {
4096                 return $this->getRelativeRevisionID( $revId, $flags, 'prev' );
4097         }
4098
4099         /**
4100          * Get the revision ID of the next revision
4101          *
4102          * @param int $revId Revision ID. Get the revision that was after this one.
4103          * @param int $flags Title::GAID_FOR_UPDATE
4104          * @return int|bool Next revision ID, or false if none exists
4105          */
4106         public function getNextRevisionID( $revId, $flags = 0 ) {
4107                 return $this->getRelativeRevisionID( $revId, $flags, 'next' );
4108         }
4109
4110         /**
4111          * Get the first revision of the page
4112          *
4113          * @param int $flags Title::GAID_FOR_UPDATE
4114          * @return Revision|null If page doesn't exist
4115          */
4116         public function getFirstRevision( $flags = 0 ) {
4117                 $pageId = $this->getArticleID( $flags );
4118                 if ( $pageId ) {
4119                         $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_REPLICA );
4120                         $row = $db->selectRow( 'revision', Revision::selectFields(),
4121                                 [ 'rev_page' => $pageId ],
4122                                 __METHOD__,
4123                                 [
4124                                         'ORDER BY' => 'rev_timestamp ASC, rev_id ASC',
4125                                         'IGNORE INDEX' => 'rev_timestamp', // See T159319
4126                                 ]
4127                         );
4128                         if ( $row ) {
4129                                 return new Revision( $row );
4130                         }
4131                 }
4132                 return null;
4133         }
4134
4135         /**
4136          * Get the oldest revision timestamp of this page
4137          *
4138          * @param int $flags Title::GAID_FOR_UPDATE
4139          * @return string MW timestamp
4140          */
4141         public function getEarliestRevTime( $flags = 0 ) {
4142                 $rev = $this->getFirstRevision( $flags );
4143                 return $rev ? $rev->getTimestamp() : null;
4144         }
4145
4146         /**
4147          * Check if this is a new page
4148          *
4149          * @return bool
4150          */
4151         public function isNewPage() {
4152                 $dbr = wfGetDB( DB_REPLICA );
4153                 return (bool)$dbr->selectField( 'page', 'page_is_new', $this->pageCond(), __METHOD__ );
4154         }
4155
4156         /**
4157          * Check whether the number of revisions of this page surpasses $wgDeleteRevisionsLimit
4158          *
4159          * @return bool
4160          */
4161         public function isBigDeletion() {
4162                 global $wgDeleteRevisionsLimit;
4163
4164                 if ( !$wgDeleteRevisionsLimit ) {
4165                         return false;
4166                 }
4167
4168                 if ( $this->mIsBigDeletion === null ) {
4169                         $dbr = wfGetDB( DB_REPLICA );
4170
4171                         $revCount = $dbr->selectRowCount(
4172                                 'revision',
4173                                 '1',
4174                                 [ 'rev_page' => $this->getArticleID() ],
4175                                 __METHOD__,
4176                                 [ 'LIMIT' => $wgDeleteRevisionsLimit + 1 ]
4177                         );
4178
4179                         $this->mIsBigDeletion = $revCount > $wgDeleteRevisionsLimit;
4180                 }
4181
4182                 return $this->mIsBigDeletion;
4183         }
4184
4185         /**
4186          * Get the approximate revision count of this page.
4187          *
4188          * @return int
4189          */
4190         public function estimateRevisionCount() {
4191                 if ( !$this->exists() ) {
4192                         return 0;
4193                 }
4194
4195                 if ( $this->mEstimateRevisions === null ) {
4196                         $dbr = wfGetDB( DB_REPLICA );
4197                         $this->mEstimateRevisions = $dbr->estimateRowCount( 'revision', '*',
4198                                 [ 'rev_page' => $this->getArticleID() ], __METHOD__ );
4199                 }
4200
4201                 return $this->mEstimateRevisions;
4202         }
4203
4204         /**
4205          * Get the number of revisions between the given revision.
4206          * Used for diffs and other things that really need it.
4207          *
4208          * @param int|Revision $old Old revision or rev ID (first before range)
4209          * @param int|Revision $new New revision or rev ID (first after range)
4210          * @param int|null $max Limit of Revisions to count, will be incremented to detect truncations
4211          * @return int Number of revisions between these revisions.
4212          */
4213         public function countRevisionsBetween( $old, $new, $max = null ) {
4214                 if ( !( $old instanceof Revision ) ) {
4215                         $old = Revision::newFromTitle( $this, (int)$old );
4216                 }
4217                 if ( !( $new instanceof Revision ) ) {
4218                         $new = Revision::newFromTitle( $this, (int)$new );
4219                 }
4220                 if ( !$old || !$new ) {
4221                         return 0; // nothing to compare
4222                 }
4223                 $dbr = wfGetDB( DB_REPLICA );
4224                 $conds = [
4225                         'rev_page' => $this->getArticleID(),
4226                         'rev_timestamp > ' . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4227                         'rev_timestamp < ' . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4228                 ];
4229                 if ( $max !== null ) {
4230                         return $dbr->selectRowCount( 'revision', '1',
4231                                 $conds,
4232                                 __METHOD__,
4233                                 [ 'LIMIT' => $max + 1 ] // extra to detect truncation
4234                         );
4235                 } else {
4236                         return (int)$dbr->selectField( 'revision', 'count(*)', $conds, __METHOD__ );
4237                 }
4238         }
4239
4240         /**
4241          * Get the authors between the given revisions or revision IDs.
4242          * Used for diffs and other things that really need it.
4243          *
4244          * @since 1.23
4245          *
4246          * @param int|Revision $old Old revision or rev ID (first before range by default)
4247          * @param int|Revision $new New revision or rev ID (first after range by default)
4248          * @param int $limit Maximum number of authors
4249          * @param string|array $options (Optional): Single option, or an array of options:
4250          *     'include_old' Include $old in the range; $new is excluded.
4251          *     'include_new' Include $new in the range; $old is excluded.
4252          *     'include_both' Include both $old and $new in the range.
4253          *     Unknown option values are ignored.
4254          * @return array|null Names of revision authors in the range; null if not both revisions exist
4255          */
4256         public function getAuthorsBetween( $old, $new, $limit, $options = [] ) {
4257                 if ( !( $old instanceof Revision ) ) {
4258                         $old = Revision::newFromTitle( $this, (int)$old );
4259                 }
4260                 if ( !( $new instanceof Revision ) ) {
4261                         $new = Revision::newFromTitle( $this, (int)$new );
4262                 }
4263                 // XXX: what if Revision objects are passed in, but they don't refer to this title?
4264                 // Add $old->getPage() != $new->getPage() || $old->getPage() != $this->getArticleID()
4265                 // in the sanity check below?
4266                 if ( !$old || !$new ) {
4267                         return null; // nothing to compare
4268                 }
4269                 $authors = [];
4270                 $old_cmp = '>';
4271                 $new_cmp = '<';
4272                 $options = (array)$options;
4273                 if ( in_array( 'include_old', $options ) ) {
4274                         $old_cmp = '>=';
4275                 }
4276                 if ( in_array( 'include_new', $options ) ) {
4277                         $new_cmp = '<=';
4278                 }
4279                 if ( in_array( 'include_both', $options ) ) {
4280                         $old_cmp = '>=';
4281                         $new_cmp = '<=';
4282                 }
4283                 // No DB query needed if $old and $new are the same or successive revisions:
4284                 if ( $old->getId() === $new->getId() ) {
4285                         return ( $old_cmp === '>' && $new_cmp === '<' ) ?
4286                                 [] :
4287                                 [ $old->getUserText( Revision::RAW ) ];
4288                 } elseif ( $old->getId() === $new->getParentId() ) {
4289                         if ( $old_cmp === '>=' && $new_cmp === '<=' ) {
4290                                 $authors[] = $old->getUserText( Revision::RAW );
4291                                 if ( $old->getUserText( Revision::RAW ) != $new->getUserText( Revision::RAW ) ) {
4292                                         $authors[] = $new->getUserText( Revision::RAW );
4293                                 }
4294                         } elseif ( $old_cmp === '>=' ) {
4295                                 $authors[] = $old->getUserText( Revision::RAW );
4296                         } elseif ( $new_cmp === '<=' ) {
4297                                 $authors[] = $new->getUserText( Revision::RAW );
4298                         }
4299                         return $authors;
4300                 }
4301                 $dbr = wfGetDB( DB_REPLICA );
4302                 $res = $dbr->select( 'revision', 'DISTINCT rev_user_text',
4303                         [
4304                                 'rev_page' => $this->getArticleID(),
4305                                 "rev_timestamp $old_cmp " . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4306                                 "rev_timestamp $new_cmp " . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4307                         ], __METHOD__,
4308                         [ 'LIMIT' => $limit + 1 ] // add one so caller knows it was truncated
4309                 );
4310                 foreach ( $res as $row ) {
4311                         $authors[] = $row->rev_user_text;
4312                 }
4313                 return $authors;
4314         }
4315
4316         /**
4317          * Get the number of authors between the given revisions or revision IDs.
4318          * Used for diffs and other things that really need it.
4319          *
4320          * @param int|Revision $old Old revision or rev ID (first before range by default)
4321          * @param int|Revision $new New revision or rev ID (first after range by default)
4322          * @param int $limit Maximum number of authors
4323          * @param string|array $options (Optional): Single option, or an array of options:
4324          *     'include_old' Include $old in the range; $new is excluded.
4325          *     'include_new' Include $new in the range; $old is excluded.
4326          *     'include_both' Include both $old and $new in the range.
4327          *     Unknown option values are ignored.
4328          * @return int Number of revision authors in the range; zero if not both revisions exist
4329          */
4330         public function countAuthorsBetween( $old, $new, $limit, $options = [] ) {
4331                 $authors = $this->getAuthorsBetween( $old, $new, $limit, $options );
4332                 return $authors ? count( $authors ) : 0;
4333         }
4334
4335         /**
4336          * Compare with another title.
4337          *
4338          * @param Title $title
4339          * @return bool
4340          */
4341         public function equals( Title $title ) {
4342                 // Note: === is necessary for proper matching of number-like titles.
4343                 return $this->getInterwiki() === $title->getInterwiki()
4344                         && $this->getNamespace() == $title->getNamespace()
4345                         && $this->getDBkey() === $title->getDBkey();
4346         }
4347
4348         /**
4349          * Check if this title is a subpage of another title
4350          *
4351          * @param Title $title
4352          * @return bool
4353          */
4354         public function isSubpageOf( Title $title ) {
4355                 return $this->getInterwiki() === $title->getInterwiki()
4356                         && $this->getNamespace() == $title->getNamespace()
4357                         && strpos( $this->getDBkey(), $title->getDBkey() . '/' ) === 0;
4358         }
4359
4360         /**
4361          * Check if page exists.  For historical reasons, this function simply
4362          * checks for the existence of the title in the page table, and will
4363          * thus return false for interwiki links, special pages and the like.
4364          * If you want to know if a title can be meaningfully viewed, you should
4365          * probably call the isKnown() method instead.
4366          *
4367          * @param int $flags An optional bit field; may be Title::GAID_FOR_UPDATE to check
4368          *   from master/for update
4369          * @return bool
4370          */
4371         public function exists( $flags = 0 ) {
4372                 $exists = $this->getArticleID( $flags ) != 0;
4373                 Hooks::run( 'TitleExists', [ $this, &$exists ] );
4374                 return $exists;
4375         }
4376
4377         /**
4378          * Should links to this title be shown as potentially viewable (i.e. as
4379          * "bluelinks"), even if there's no record by this title in the page
4380          * table?
4381          *
4382          * This function is semi-deprecated for public use, as well as somewhat
4383          * misleadingly named.  You probably just want to call isKnown(), which
4384          * calls this function internally.
4385          *
4386          * (ISSUE: Most of these checks are cheap, but the file existence check
4387          * can potentially be quite expensive.  Including it here fixes a lot of
4388          * existing code, but we might want to add an optional parameter to skip
4389          * it and any other expensive checks.)
4390          *
4391          * @return bool
4392          */
4393         public function isAlwaysKnown() {
4394                 $isKnown = null;
4395
4396                 /**
4397                  * Allows overriding default behavior for determining if a page exists.
4398                  * If $isKnown is kept as null, regular checks happen. If it's
4399                  * a boolean, this value is returned by the isKnown method.
4400                  *
4401                  * @since 1.20
4402                  *
4403                  * @param Title $title
4404                  * @param bool|null $isKnown
4405                  */
4406                 Hooks::run( 'TitleIsAlwaysKnown', [ $this, &$isKnown ] );
4407
4408                 if ( !is_null( $isKnown ) ) {
4409                         return $isKnown;
4410                 }
4411
4412                 if ( $this->isExternal() ) {
4413                         return true;  // any interwiki link might be viewable, for all we know
4414                 }
4415
4416                 switch ( $this->mNamespace ) {
4417                         case NS_MEDIA:
4418                         case NS_FILE:
4419                                 // file exists, possibly in a foreign repo
4420                                 return (bool)wfFindFile( $this );
4421                         case NS_SPECIAL:
4422                                 // valid special page
4423                                 return SpecialPageFactory::exists( $this->getDBkey() );
4424                         case NS_MAIN:
4425                                 // selflink, possibly with fragment
4426                                 return $this->mDbkeyform == '';
4427                         case NS_MEDIAWIKI:
4428                                 // known system message
4429                                 return $this->hasSourceText() !== false;
4430                         default:
4431                                 return false;
4432                 }
4433         }
4434
4435         /**
4436          * Does this title refer to a page that can (or might) be meaningfully
4437          * viewed?  In particular, this function may be used to determine if
4438          * links to the title should be rendered as "bluelinks" (as opposed to
4439          * "redlinks" to non-existent pages).
4440          * Adding something else to this function will cause inconsistency
4441          * since LinkHolderArray calls isAlwaysKnown() and does its own
4442          * page existence check.
4443          *
4444          * @return bool
4445          */
4446         public function isKnown() {
4447                 return $this->isAlwaysKnown() || $this->exists();
4448         }
4449
4450         /**
4451          * Does this page have source text?
4452          *
4453          * @return bool
4454          */
4455         public function hasSourceText() {
4456                 if ( $this->exists() ) {
4457                         return true;
4458                 }
4459
4460                 if ( $this->mNamespace == NS_MEDIAWIKI ) {
4461                         // If the page doesn't exist but is a known system message, default
4462                         // message content will be displayed, same for language subpages-
4463                         // Use always content language to avoid loading hundreds of languages
4464                         // to get the link color.
4465                         global $wgContLang;
4466                         list( $name, ) = MessageCache::singleton()->figureMessage(
4467                                 $wgContLang->lcfirst( $this->getText() )
4468                         );
4469                         $message = wfMessage( $name )->inLanguage( $wgContLang )->useDatabase( false );
4470                         return $message->exists();
4471                 }
4472
4473                 return false;
4474         }
4475
4476         /**
4477          * Get the default message text or false if the message doesn't exist
4478          *
4479          * @return string|bool
4480          */
4481         public function getDefaultMessageText() {
4482                 global $wgContLang;
4483
4484                 if ( $this->getNamespace() != NS_MEDIAWIKI ) { // Just in case
4485                         return false;
4486                 }
4487
4488                 list( $name, $lang ) = MessageCache::singleton()->figureMessage(
4489                         $wgContLang->lcfirst( $this->getText() )
4490                 );
4491                 $message = wfMessage( $name )->inLanguage( $lang )->useDatabase( false );
4492
4493                 if ( $message->exists() ) {
4494                         return $message->plain();
4495                 } else {
4496                         return false;
4497                 }
4498         }
4499
4500         /**
4501          * Updates page_touched for this page; called from LinksUpdate.php
4502          *
4503          * @param string $purgeTime [optional] TS_MW timestamp
4504          * @return bool True if the update succeeded
4505          */
4506         public function invalidateCache( $purgeTime = null ) {
4507                 if ( wfReadOnly() ) {
4508                         return false;
4509                 } elseif ( $this->mArticleID === 0 ) {
4510                         return true; // avoid gap locking if we know it's not there
4511                 }
4512
4513                 $dbw = wfGetDB( DB_MASTER );
4514                 $dbw->onTransactionPreCommitOrIdle( function () {
4515                         ResourceLoaderWikiModule::invalidateModuleCache( $this, null, null, wfWikiID() );
4516                 } );
4517
4518                 $conds = $this->pageCond();
4519                 DeferredUpdates::addUpdate(
4520                         new AutoCommitUpdate(
4521                                 $dbw,
4522                                 __METHOD__,
4523                                 function ( IDatabase $dbw, $fname ) use ( $conds, $purgeTime ) {
4524                                         $dbTimestamp = $dbw->timestamp( $purgeTime ?: time() );
4525                                         $dbw->update(
4526                                                 'page',
4527                                                 [ 'page_touched' => $dbTimestamp ],
4528                                                 $conds + [ 'page_touched < ' . $dbw->addQuotes( $dbTimestamp ) ],
4529                                                 $fname
4530                                         );
4531                                         MediaWikiServices::getInstance()->getLinkCache()->invalidateTitle( $this );
4532                                 }
4533                         ),
4534                         DeferredUpdates::PRESEND
4535                 );
4536
4537                 return true;
4538         }
4539
4540         /**
4541          * Update page_touched timestamps and send CDN purge messages for
4542          * pages linking to this title. May be sent to the job queue depending
4543          * on the number of links. Typically called on create and delete.
4544          */
4545         public function touchLinks() {
4546                 DeferredUpdates::addUpdate( new HTMLCacheUpdate( $this, 'pagelinks' ) );
4547                 if ( $this->getNamespace() == NS_CATEGORY ) {
4548                         DeferredUpdates::addUpdate( new HTMLCacheUpdate( $this, 'categorylinks' ) );
4549                 }
4550         }
4551
4552         /**
4553          * Get the last touched timestamp
4554          *
4555          * @param IDatabase $db Optional db
4556          * @return string|false Last-touched timestamp
4557          */
4558         public function getTouched( $db = null ) {
4559                 if ( $db === null ) {
4560                         $db = wfGetDB( DB_REPLICA );
4561                 }
4562                 $touched = $db->selectField( 'page', 'page_touched', $this->pageCond(), __METHOD__ );
4563                 return $touched;
4564         }
4565
4566         /**
4567          * Get the timestamp when this page was updated since the user last saw it.
4568          *
4569          * @param User $user
4570          * @return string|null
4571          */
4572         public function getNotificationTimestamp( $user = null ) {
4573                 global $wgUser;
4574
4575                 // Assume current user if none given
4576                 if ( !$user ) {
4577                         $user = $wgUser;
4578                 }
4579                 // Check cache first
4580                 $uid = $user->getId();
4581                 if ( !$uid ) {
4582                         return false;
4583                 }
4584                 // avoid isset here, as it'll return false for null entries
4585                 if ( array_key_exists( $uid, $this->mNotificationTimestamp ) ) {
4586                         return $this->mNotificationTimestamp[$uid];
4587                 }
4588                 // Don't cache too much!
4589                 if ( count( $this->mNotificationTimestamp ) >= self::CACHE_MAX ) {
4590                         $this->mNotificationTimestamp = [];
4591                 }
4592
4593                 $store = MediaWikiServices::getInstance()->getWatchedItemStore();
4594                 $watchedItem = $store->getWatchedItem( $user, $this );
4595                 if ( $watchedItem ) {
4596                         $this->mNotificationTimestamp[$uid] = $watchedItem->getNotificationTimestamp();
4597                 } else {
4598                         $this->mNotificationTimestamp[$uid] = false;
4599                 }
4600
4601                 return $this->mNotificationTimestamp[$uid];
4602         }
4603
4604         /**
4605          * Generate strings used for xml 'id' names in monobook tabs
4606          *
4607          * @param string $prepend Defaults to 'nstab-'
4608          * @return string XML 'id' name
4609          */
4610         public function getNamespaceKey( $prepend = 'nstab-' ) {
4611                 global $wgContLang;
4612                 // Gets the subject namespace if this title
4613                 $namespace = MWNamespace::getSubject( $this->getNamespace() );
4614                 // Checks if canonical namespace name exists for namespace
4615                 if ( MWNamespace::exists( $this->getNamespace() ) ) {
4616                         // Uses canonical namespace name
4617                         $namespaceKey = MWNamespace::getCanonicalName( $namespace );
4618                 } else {
4619                         // Uses text of namespace
4620                         $namespaceKey = $this->getSubjectNsText();
4621                 }
4622                 // Makes namespace key lowercase
4623                 $namespaceKey = $wgContLang->lc( $namespaceKey );
4624                 // Uses main
4625                 if ( $namespaceKey == '' ) {
4626                         $namespaceKey = 'main';
4627                 }
4628                 // Changes file to image for backwards compatibility
4629                 if ( $namespaceKey == 'file' ) {
4630                         $namespaceKey = 'image';
4631                 }
4632                 return $prepend . $namespaceKey;
4633         }
4634
4635         /**
4636          * Get all extant redirects to this Title
4637          *
4638          * @param int|null $ns Single namespace to consider; null to consider all namespaces
4639          * @return Title[] Array of Title redirects to this title
4640          */
4641         public function getRedirectsHere( $ns = null ) {
4642                 $redirs = [];
4643
4644                 $dbr = wfGetDB( DB_REPLICA );
4645                 $where = [
4646                         'rd_namespace' => $this->getNamespace(),
4647                         'rd_title' => $this->getDBkey(),
4648                         'rd_from = page_id'
4649                 ];
4650                 if ( $this->isExternal() ) {
4651                         $where['rd_interwiki'] = $this->getInterwiki();
4652                 } else {
4653                         $where[] = 'rd_interwiki = ' . $dbr->addQuotes( '' ) . ' OR rd_interwiki IS NULL';
4654                 }
4655                 if ( !is_null( $ns ) ) {
4656                         $where['page_namespace'] = $ns;
4657                 }
4658
4659                 $res = $dbr->select(
4660                         [ 'redirect', 'page' ],
4661                         [ 'page_namespace', 'page_title' ],
4662                         $where,
4663                         __METHOD__
4664                 );
4665
4666                 foreach ( $res as $row ) {
4667                         $redirs[] = self::newFromRow( $row );
4668                 }
4669                 return $redirs;
4670         }
4671
4672         /**
4673          * Check if this Title is a valid redirect target
4674          *
4675          * @return bool
4676          */
4677         public function isValidRedirectTarget() {
4678                 global $wgInvalidRedirectTargets;
4679
4680                 if ( $this->isSpecialPage() ) {
4681                         // invalid redirect targets are stored in a global array, but explicitly disallow Userlogout here
4682                         if ( $this->isSpecial( 'Userlogout' ) ) {
4683                                 return false;
4684                         }
4685
4686                         foreach ( $wgInvalidRedirectTargets as $target ) {
4687                                 if ( $this->isSpecial( $target ) ) {
4688                                         return false;
4689                                 }
4690                         }
4691                 }
4692
4693                 return true;
4694         }
4695
4696         /**
4697          * Get a backlink cache object
4698          *
4699          * @return BacklinkCache
4700          */
4701         public function getBacklinkCache() {
4702                 return BacklinkCache::get( $this );
4703         }
4704
4705         /**
4706          * Whether the magic words __INDEX__ and __NOINDEX__ function for this page.
4707          *
4708          * @return bool
4709          */
4710         public function canUseNoindex() {
4711                 global $wgExemptFromUserRobotsControl;
4712
4713                 $bannedNamespaces = is_null( $wgExemptFromUserRobotsControl )
4714                         ? MWNamespace::getContentNamespaces()
4715                         : $wgExemptFromUserRobotsControl;
4716
4717                 return !in_array( $this->mNamespace, $bannedNamespaces );
4718         }
4719
4720         /**
4721          * Returns the raw sort key to be used for categories, with the specified
4722          * prefix.  This will be fed to Collation::getSortKey() to get a
4723          * binary sortkey that can be used for actual sorting.
4724          *
4725          * @param string $prefix The prefix to be used, specified using
4726          *   {{defaultsort:}} or like [[Category:Foo|prefix]].  Empty for no
4727          *   prefix.
4728          * @return string
4729          */
4730         public function getCategorySortkey( $prefix = '' ) {
4731                 $unprefixed = $this->getText();
4732
4733                 // Anything that uses this hook should only depend
4734                 // on the Title object passed in, and should probably
4735                 // tell the users to run updateCollations.php --force
4736                 // in order to re-sort existing category relations.
4737                 Hooks::run( 'GetDefaultSortkey', [ $this, &$unprefixed ] );
4738                 if ( $prefix !== '' ) {
4739                         # Separate with a line feed, so the unprefixed part is only used as
4740                         # a tiebreaker when two pages have the exact same prefix.
4741                         # In UCA, tab is the only character that can sort above LF
4742                         # so we strip both of them from the original prefix.
4743                         $prefix = strtr( $prefix, "\n\t", '  ' );
4744                         return "$prefix\n$unprefixed";
4745                 }
4746                 return $unprefixed;
4747         }
4748
4749         /**
4750          * Returns the page language code saved in the database, if $wgPageLanguageUseDB is set
4751          * to true in LocalSettings.php, otherwise returns false. If there is no language saved in
4752          * the db, it will return NULL.
4753          *
4754          * @return string|null|bool
4755          */
4756         private function getDbPageLanguageCode() {
4757                 global $wgPageLanguageUseDB;
4758
4759                 // check, if the page language could be saved in the database, and if so and
4760                 // the value is not requested already, lookup the page language using LinkCache
4761                 if ( $wgPageLanguageUseDB && $this->mDbPageLanguage === false ) {
4762                         $linkCache = LinkCache::singleton();
4763                         $linkCache->addLinkObj( $this );
4764                         $this->mDbPageLanguage = $linkCache->getGoodLinkFieldObj( $this, 'lang' );
4765                 }
4766
4767                 return $this->mDbPageLanguage;
4768         }
4769
4770         /**
4771          * Get the language in which the content of this page is written in
4772          * wikitext. Defaults to $wgContLang, but in certain cases it can be
4773          * e.g. $wgLang (such as special pages, which are in the user language).
4774          *
4775          * @since 1.18
4776          * @return Language
4777          */
4778         public function getPageLanguage() {
4779                 global $wgLang, $wgLanguageCode;
4780                 if ( $this->isSpecialPage() ) {
4781                         // special pages are in the user language
4782                         return $wgLang;
4783                 }
4784
4785                 // Checking if DB language is set
4786                 $dbPageLanguage = $this->getDbPageLanguageCode();
4787                 if ( $dbPageLanguage ) {
4788                         return wfGetLangObj( $dbPageLanguage );
4789                 }
4790
4791                 if ( !$this->mPageLanguage || $this->mPageLanguage[1] !== $wgLanguageCode ) {
4792                         // Note that this may depend on user settings, so the cache should
4793                         // be only per-request.
4794                         // NOTE: ContentHandler::getPageLanguage() may need to load the
4795                         // content to determine the page language!
4796                         // Checking $wgLanguageCode hasn't changed for the benefit of unit
4797                         // tests.
4798                         $contentHandler = ContentHandler::getForTitle( $this );
4799                         $langObj = $contentHandler->getPageLanguage( $this );
4800                         $this->mPageLanguage = [ $langObj->getCode(), $wgLanguageCode ];
4801                 } else {
4802                         $langObj = wfGetLangObj( $this->mPageLanguage[0] );
4803                 }
4804
4805                 return $langObj;
4806         }
4807
4808         /**
4809          * Get the language in which the content of this page is written when
4810          * viewed by user. Defaults to $wgContLang, but in certain cases it can be
4811          * e.g. $wgLang (such as special pages, which are in the user language).
4812          *
4813          * @since 1.20
4814          * @return Language
4815          */
4816         public function getPageViewLanguage() {
4817                 global $wgLang;
4818
4819                 if ( $this->isSpecialPage() ) {
4820                         // If the user chooses a variant, the content is actually
4821                         // in a language whose code is the variant code.
4822                         $variant = $wgLang->getPreferredVariant();
4823                         if ( $wgLang->getCode() !== $variant ) {
4824                                 return Language::factory( $variant );
4825                         }
4826
4827                         return $wgLang;
4828                 }
4829
4830                 // Checking if DB language is set
4831                 $dbPageLanguage = $this->getDbPageLanguageCode();
4832                 if ( $dbPageLanguage ) {
4833                         $pageLang = wfGetLangObj( $dbPageLanguage );
4834                         $variant = $pageLang->getPreferredVariant();
4835                         if ( $pageLang->getCode() !== $variant ) {
4836                                 $pageLang = Language::factory( $variant );
4837                         }
4838
4839                         return $pageLang;
4840                 }
4841
4842                 // @note Can't be cached persistently, depends on user settings.
4843                 // @note ContentHandler::getPageViewLanguage() may need to load the
4844                 //   content to determine the page language!
4845                 $contentHandler = ContentHandler::getForTitle( $this );
4846                 $pageLang = $contentHandler->getPageViewLanguage( $this );
4847                 return $pageLang;
4848         }
4849
4850         /**
4851          * Get a list of rendered edit notices for this page.
4852          *
4853          * Array is keyed by the original message key, and values are rendered using parseAsBlock, so
4854          * they will already be wrapped in paragraphs.
4855          *
4856          * @since 1.21
4857          * @param int $oldid Revision ID that's being edited
4858          * @return array
4859          */
4860         public function getEditNotices( $oldid = 0 ) {
4861                 $notices = [];
4862
4863                 // Optional notice for the entire namespace
4864                 $editnotice_ns = 'editnotice-' . $this->getNamespace();
4865                 $msg = wfMessage( $editnotice_ns );
4866                 if ( $msg->exists() ) {
4867                         $html = $msg->parseAsBlock();
4868                         // Edit notices may have complex logic, but output nothing (T91715)
4869                         if ( trim( $html ) !== '' ) {
4870                                 $notices[$editnotice_ns] = Html::rawElement(
4871                                         'div',
4872                                         [ 'class' => [
4873                                                 'mw-editnotice',
4874                                                 'mw-editnotice-namespace',
4875                                                 Sanitizer::escapeClass( "mw-$editnotice_ns" )
4876                                         ] ],
4877                                         $html
4878                                 );
4879                         }
4880                 }
4881
4882                 if ( MWNamespace::hasSubpages( $this->getNamespace() ) ) {
4883                         // Optional notice for page itself and any parent page
4884                         $parts = explode( '/', $this->getDBkey() );
4885                         $editnotice_base = $editnotice_ns;
4886                         while ( count( $parts ) > 0 ) {
4887                                 $editnotice_base .= '-' . array_shift( $parts );
4888                                 $msg = wfMessage( $editnotice_base );
4889                                 if ( $msg->exists() ) {
4890                                         $html = $msg->parseAsBlock();
4891                                         if ( trim( $html ) !== '' ) {
4892                                                 $notices[$editnotice_base] = Html::rawElement(
4893                                                         'div',
4894                                                         [ 'class' => [
4895                                                                 'mw-editnotice',
4896                                                                 'mw-editnotice-base',
4897                                                                 Sanitizer::escapeClass( "mw-$editnotice_base" )
4898                                                         ] ],
4899                                                         $html
4900                                                 );
4901                                         }
4902                                 }
4903                         }
4904                 } else {
4905                         // Even if there are no subpages in namespace, we still don't want "/" in MediaWiki message keys
4906                         $editnoticeText = $editnotice_ns . '-' . strtr( $this->getDBkey(), '/', '-' );
4907                         $msg = wfMessage( $editnoticeText );
4908                         if ( $msg->exists() ) {
4909                                 $html = $msg->parseAsBlock();
4910                                 if ( trim( $html ) !== '' ) {
4911                                         $notices[$editnoticeText] = Html::rawElement(
4912                                                 'div',
4913                                                 [ 'class' => [
4914                                                         'mw-editnotice',
4915                                                         'mw-editnotice-page',
4916                                                         Sanitizer::escapeClass( "mw-$editnoticeText" )
4917                                                 ] ],
4918                                                 $html
4919                                         );
4920                                 }
4921                         }
4922                 }
4923
4924                 Hooks::run( 'TitleGetEditNotices', [ $this, $oldid, &$notices ] );
4925                 return $notices;
4926         }
4927
4928         /**
4929          * @return array
4930          */
4931         public function __sleep() {
4932                 return [
4933                         'mNamespace',
4934                         'mDbkeyform',
4935                         'mFragment',
4936                         'mInterwiki',
4937                         'mLocalInterwiki',
4938                         'mUserCaseDBKey',
4939                         'mDefaultNamespace',
4940                 ];
4941         }
4942
4943         public function __wakeup() {
4944                 $this->mArticleID = ( $this->mNamespace >= 0 ) ? -1 : 0;
4945                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
4946                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
4947         }
4948
4949 }