includes/Title.php

   1 <?php
   2 /**
   3  * Representation of a title within %MediaWiki.
   4  *
   5  * See title.txt
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License along
  18  * with this program; if not, write to the Free Software Foundation, Inc.,
  19  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  20  * http://www.gnu.org/copyleft/gpl.html
  21  *
  22  * @file
  23  */
  24
  25 use Wikimedia\Rdbms\Database;
  26 use Wikimedia\Rdbms\IDatabase;
  27 use MediaWiki\Linker\LinkTarget;
  28 use MediaWiki\Interwiki\InterwikiLookup;
  29 use MediaWiki\MediaWikiServices;
  30
  31 /**
  32  * Represents a title within MediaWiki.
  33  * Optionally may contain an interwiki designation or namespace.
  34  * @note This class can fetch various kinds of data from the database;
  35  *       however, it does so inefficiently.
  36  * @note Consider using a TitleValue object instead. TitleValue is more lightweight
  37  *       and does not rely on global state or the database.
  38  */
  39 class Title implements LinkTarget {
  40         /** @var HashBagOStuff */
  41         static private $titleCache = null;
  42
  43         /**
  44          * Title::newFromText maintains a cache to avoid expensive re-normalization of
  45          * commonly used titles. On a batch operation this can become a memory leak
  46          * if not bounded. After hitting this many titles reset the cache.
  47          */
  48         const CACHE_MAX = 1000;
  49
  50         /**
  51          * Used to be GAID_FOR_UPDATE define. Used with getArticleID() and friends
  52          * to use the master DB
  53          */
  54         const GAID_FOR_UPDATE = 1;
  55
  56         /**
  57          * @name Private member variables
  58          * Please use the accessor functions instead.
  59          * @private
  60          */
  61         // @{
  62
  63         /** @var string Text form (spaces not underscores) of the main part */
  64         public $mTextform = '';
  65
  66         /** @var string URL-encoded form of the main part */
  67         public $mUrlform = '';
  68
  69         /** @var string Main part with underscores */
  70         public $mDbkeyform = '';
  71
  72         /** @var string Database key with the initial letter in the case specified by the user */
  73         protected $mUserCaseDBKey;
  74
  75         /** @var int Namespace index, i.e. one of the NS_xxxx constants */
  76         public $mNamespace = NS_MAIN;
  77
  78         /** @var string Interwiki prefix */
  79         public $mInterwiki = '';
  80
  81         /** @var bool Was this Title created from a string with a local interwiki prefix? */
  82         private $mLocalInterwiki = false;
  83
  84         /** @var string Title fragment (i.e. the bit after the #) */
  85         public $mFragment = '';
  86
  87         /** @var int Article ID, fetched from the link cache on demand */
  88         public $mArticleID = -1;
  89
  90         /** @var bool|int ID of most recent revision */
  91         protected $mLatestID = false;
  92
  93         /**
  94          * @var bool|string ID of the page's content model, i.e. one of the
  95          *   CONTENT_MODEL_XXX constants
  96          */
  97         private $mContentModel = false;
  98
  99         /**
 100          * @var bool If a content model was forced via setContentModel()
 101          *   this will be true to avoid having other code paths reset it
 102          */
 103         private $mForcedContentModel = false;
 104
 105         /** @var int Estimated number of revisions; null of not loaded */
 106         private $mEstimateRevisions;
 107
 108         /** @var array Array of groups allowed to edit this article */
 109         public $mRestrictions = [];
 110
 111         /** @var string|bool */
 112         protected $mOldRestrictions = false;
 113
 114         /** @var bool Cascade restrictions on this page to included templates and images? */
 115         public $mCascadeRestriction;
 116
 117         /** Caching the results of getCascadeProtectionSources */
 118         public $mCascadingRestrictions;
 119
 120         /** @var array When do the restrictions on this page expire? */
 121         protected $mRestrictionsExpiry = [];
 122
 123         /** @var bool Are cascading restrictions in effect on this page? */
 124         protected $mHasCascadingRestrictions;
 125
 126         /** @var array Where are the cascading restrictions coming from on this page? */
 127         public $mCascadeSources;
 128
 129         /** @var bool Boolean for initialisation on demand */
 130         public $mRestrictionsLoaded = false;
 131
 132         /** @var string Text form including namespace/interwiki, initialised on demand */
 133         protected $mPrefixedText = null;
 134
 135         /** @var mixed Cached value for getTitleProtection (create protection) */
 136         public $mTitleProtection;
 137
 138         /**
 139          * @var int Namespace index when there is no namespace. Don't change the
 140          *   following default, NS_MAIN is hardcoded in several places. See T2696.
 141          *   Zero except in {{transclusion}} tags.
 142          */
 143         public $mDefaultNamespace = NS_MAIN;
 144
 145         /** @var int The page length, 0 for special pages */
 146         protected $mLength = -1;
 147
 148         /** @var null Is the article at this title a redirect? */
 149         public $mRedirect = null;
 150
 151         /** @var array Associative array of user ID -> timestamp/false */
 152         private $mNotificationTimestamp = [];
 153
 154         /** @var bool Whether a page has any subpages */
 155         private $mHasSubpages;
 156
 157         /** @var bool The (string) language code of the page's language and content code. */
 158         private $mPageLanguage = false;
 159
 160         /** @var string|bool|null The page language code from the database, null if not saved in
 161          * the database or false if not loaded, yet. */
 162         private $mDbPageLanguage = false;
 163
 164         /** @var TitleValue A corresponding TitleValue object */
 165         private $mTitleValue = null;
 166
 167         /** @var bool Would deleting this page be a big deletion? */
 168         private $mIsBigDeletion = null;
 169         // @}
 170
 171         /**
 172          * B/C kludge: provide a TitleParser for use by Title.
 173          * Ideally, Title would have no methods that need this.
 174          * Avoid usage of this singleton by using TitleValue
 175          * and the associated services when possible.
 176          *
 177          * @return TitleFormatter
 178          */
 179         private static function getTitleFormatter() {
 180                 return MediaWikiServices::getInstance()->getTitleFormatter();
 181         }
 182
 183         /**
 184          * B/C kludge: provide an InterwikiLookup for use by Title.
 185          * Ideally, Title would have no methods that need this.
 186          * Avoid usage of this singleton by using TitleValue
 187          * and the associated services when possible.
 188          *
 189          * @return InterwikiLookup
 190          */
 191         private static function getInterwikiLookup() {
 192                 return MediaWikiServices::getInstance()->getInterwikiLookup();
 193         }
 194
 195         /**
 196          * @access protected
 197          */
 198         function __construct() {
 199         }
 200
 201         /**
 202          * Create a new Title from a prefixed DB key
 203          *
 204          * @param string $key The database key, which has underscores
 205          *      instead of spaces, possibly including namespace and
 206          *      interwiki prefixes
 207          * @return Title|null Title, or null on an error
 208          */
 209         public static function newFromDBkey( $key ) {
 210                 $t = new Title();
 211                 $t->mDbkeyform = $key;
 212
 213                 try {
 214                         $t->secureAndSplit();
 215                         return $t;
 216                 } catch ( MalformedTitleException $ex ) {
 217                         return null;
 218                 }
 219         }
 220
 221         /**
 222          * Create a new Title from a TitleValue
 223          *
 224          * @param TitleValue $titleValue Assumed to be safe.
 225          *
 226          * @return Title
 227          */
 228         public static function newFromTitleValue( TitleValue $titleValue ) {
 229                 return self::newFromLinkTarget( $titleValue );
 230         }
 231
 232         /**
 233          * Create a new Title from a LinkTarget
 234          *
 235          * @param LinkTarget $linkTarget Assumed to be safe.
 236          *
 237          * @return Title
 238          */
 239         public static function newFromLinkTarget( LinkTarget $linkTarget ) {
 240                 if ( $linkTarget instanceof Title ) {
 241                         // Special case if it's already a Title object
 242                         return $linkTarget;
 243                 }
 244                 return self::makeTitle(
 245                         $linkTarget->getNamespace(),
 246                         $linkTarget->getText(),
 247                         $linkTarget->getFragment(),
 248                         $linkTarget->getInterwiki()
 249                 );
 250         }
 251
 252         /**
 253          * Create a new Title from text, such as what one would find in a link. De-
 254          * codes any HTML entities in the text.
 255          *
 256          * @param string|int|null $text The link text; spaces, prefixes, and an
 257          *   initial ':' indicating the main namespace are accepted.
 258          * @param int $defaultNamespace The namespace to use if none is specified
 259          *   by a prefix.  If you want to force a specific namespace even if
 260          *   $text might begin with a namespace prefix, use makeTitle() or
 261          *   makeTitleSafe().
 262          * @throws InvalidArgumentException
 263          * @return Title|null Title or null on an error.
 264          */
 265         public static function newFromText( $text, $defaultNamespace = NS_MAIN ) {
 266                 // DWIM: Integers can be passed in here when page titles are used as array keys.
 267                 if ( $text !== null && !is_string( $text ) && !is_int( $text ) ) {
 268                         throw new InvalidArgumentException( '$text must be a string.' );
 269                 }
 270                 if ( $text === null ) {
 271                         return null;
 272                 }
 273
 274                 try {
 275                         return Title::newFromTextThrow( strval( $text ), $defaultNamespace );
 276                 } catch ( MalformedTitleException $ex ) {
 277                         return null;
 278                 }
 279         }
 280
 281         /**
 282          * Like Title::newFromText(), but throws MalformedTitleException when the title is invalid,
 283          * rather than returning null.
 284          *
 285          * The exception subclasses encode detailed information about why the title is invalid.
 286          *
 287          * @see Title::newFromText
 288          *
 289          * @since 1.25
 290          * @param string $text Title text to check
 291          * @param int $defaultNamespace
 292          * @throws MalformedTitleException If the title is invalid
 293          * @return Title
 294          */
 295         public static function newFromTextThrow( $text, $defaultNamespace = NS_MAIN ) {
 296                 if ( is_object( $text ) ) {
 297                         throw new MWException( '$text must be a string, given an object' );
 298                 }
 299
 300                 $titleCache = self::getTitleCache();
 301
 302                 // Wiki pages often contain multiple links to the same page.
 303                 // Title normalization and parsing can become expensive on pages with many
 304                 // links, so we can save a little time by caching them.
 305                 // In theory these are value objects and won't get changed...
 306                 if ( $defaultNamespace == NS_MAIN ) {
 307                         $t = $titleCache->get( $text );
 308                         if ( $t ) {
 309                                 return $t;
 310                         }
 311                 }
 312
 313                 // Convert things like &eacute; &#257; or &#x3017; into normalized (T16952) text
 314                 $filteredText = Sanitizer::decodeCharReferencesAndNormalize( $text );
 315
 316                 $t = new Title();
 317                 $t->mDbkeyform = strtr( $filteredText, ' ', '_' );
 318                 $t->mDefaultNamespace = intval( $defaultNamespace );
 319
 320                 $t->secureAndSplit();
 321                 if ( $defaultNamespace == NS_MAIN ) {
 322                         $titleCache->set( $text, $t );
 323                 }
 324                 return $t;
 325         }
 326
 327         /**
 328          * THIS IS NOT THE FUNCTION YOU WANT. Use Title::newFromText().
 329          *
 330          * Example of wrong and broken code:
 331          * $title = Title::newFromURL( $wgRequest->getVal( 'title' ) );
 332          *
 333          * Example of right code:
 334          * $title = Title::newFromText( $wgRequest->getVal( 'title' ) );
 335          *
 336          * Create a new Title from URL-encoded text. Ensures that
 337          * the given title's length does not exceed the maximum.
 338          *
 339          * @param string $url The title, as might be taken from a URL
 340          * @return Title|null The new object, or null on an error
 341          */
 342         public static function newFromURL( $url ) {
 343                 $t = new Title();
 344
 345                 # For compatibility with old buggy URLs. "+" is usually not valid in titles,
 346                 # but some URLs used it as a space replacement and they still come
 347                 # from some external search tools.
 348                 if ( strpos( self::legalChars(), '+' ) === false ) {
 349                         $url = strtr( $url, '+', ' ' );
 350                 }
 351
 352                 $t->mDbkeyform = strtr( $url, ' ', '_' );
 353
 354                 try {
 355                         $t->secureAndSplit();
 356                         return $t;
 357                 } catch ( MalformedTitleException $ex ) {
 358                         return null;
 359                 }
 360         }
 361
 362         /**
 363          * @return HashBagOStuff
 364          */
 365         private static function getTitleCache() {
 366                 if ( self::$titleCache == null ) {
 367                         self::$titleCache = new HashBagOStuff( [ 'maxKeys' => self::CACHE_MAX ] );
 368                 }
 369                 return self::$titleCache;
 370         }
 371
 372         /**
 373          * Returns a list of fields that are to be selected for initializing Title
 374          * objects or LinkCache entries. Uses $wgContentHandlerUseDB to determine
 375          * whether to include page_content_model.
 376          *
 377          * @return array
 378          */
 379         protected static function getSelectFields() {
 380                 global $wgContentHandlerUseDB, $wgPageLanguageUseDB;
 381
 382                 $fields = [
 383                         'page_namespace', 'page_title', 'page_id',
 384                         'page_len', 'page_is_redirect', 'page_latest',
 385                 ];
 386
 387                 if ( $wgContentHandlerUseDB ) {
 388                         $fields[] = 'page_content_model';
 389                 }
 390
 391                 if ( $wgPageLanguageUseDB ) {
 392                         $fields[] = 'page_lang';
 393                 }
 394
 395                 return $fields;
 396         }
 397
 398         /**
 399          * Create a new Title from an article ID
 400          *
 401          * @param int $id The page_id corresponding to the Title to create
 402          * @param int $flags Use Title::GAID_FOR_UPDATE to use master
 403          * @return Title|null The new object, or null on an error
 404          */
 405         public static function newFromID( $id, $flags = 0 ) {
 406                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_REPLICA );
 407                 $row = $db->selectRow(
 408                         'page',
 409                         self::getSelectFields(),
 410                         [ 'page_id' => $id ],
 411                         __METHOD__
 412                 );
 413                 if ( $row !== false ) {
 414                         $title = Title::newFromRow( $row );
 415                 } else {
 416                         $title = null;
 417                 }
 418                 return $title;
 419         }
 420
 421         /**
 422          * Make an array of titles from an array of IDs
 423          *
 424          * @param int[] $ids Array of IDs
 425          * @return Title[] Array of Titles
 426          */
 427         public static function newFromIDs( $ids ) {
 428                 if ( !count( $ids ) ) {
 429                         return [];
 430                 }
 431                 $dbr = wfGetDB( DB_REPLICA );
 432
 433                 $res = $dbr->select(
 434                         'page',
 435                         self::getSelectFields(),
 436                         [ 'page_id' => $ids ],
 437                         __METHOD__
 438                 );
 439
 440                 $titles = [];
 441                 foreach ( $res as $row ) {
 442                         $titles[] = Title::newFromRow( $row );
 443                 }
 444                 return $titles;
 445         }
 446
 447         /**
 448          * Make a Title object from a DB row
 449          *
 450          * @param stdClass $row Object database row (needs at least page_title,page_namespace)
 451          * @return Title Corresponding Title
 452          */
 453         public static function newFromRow( $row ) {
 454                 $t = self::makeTitle( $row->page_namespace, $row->page_title );
 455                 $t->loadFromRow( $row );
 456                 return $t;
 457         }
 458
 459         /**
 460          * Load Title object fields from a DB row.
 461          * If false is given, the title will be treated as non-existing.
 462          *
 463          * @param stdClass|bool $row Database row
 464          */
 465         public function loadFromRow( $row ) {
 466                 if ( $row ) { // page found
 467                         if ( isset( $row->page_id ) ) {
 468                                 $this->mArticleID = (int)$row->page_id;
 469                         }
 470                         if ( isset( $row->page_len ) ) {
 471                                 $this->mLength = (int)$row->page_len;
 472                         }
 473                         if ( isset( $row->page_is_redirect ) ) {
 474                                 $this->mRedirect = (bool)$row->page_is_redirect;
 475                         }
 476                         if ( isset( $row->page_latest ) ) {
 477                                 $this->mLatestID = (int)$row->page_latest;
 478                         }
 479                         if ( !$this->mForcedContentModel && isset( $row->page_content_model ) ) {
 480                                 $this->mContentModel = strval( $row->page_content_model );
 481                         } elseif ( !$this->mForcedContentModel ) {
 482                                 $this->mContentModel = false; # initialized lazily in getContentModel()
 483                         }
 484                         if ( isset( $row->page_lang ) ) {
 485                                 $this->mDbPageLanguage = (string)$row->page_lang;
 486                         }
 487                         if ( isset( $row->page_restrictions ) ) {
 488                                 $this->mOldRestrictions = $row->page_restrictions;
 489                         }
 490                 } else { // page not found
 491                         $this->mArticleID = 0;
 492                         $this->mLength = 0;
 493                         $this->mRedirect = false;
 494                         $this->mLatestID = 0;
 495                         if ( !$this->mForcedContentModel ) {
 496                                 $this->mContentModel = false; # initialized lazily in getContentModel()
 497                         }
 498                 }
 499         }
 500
 501         /**
 502          * Create a new Title from a namespace index and a DB key.
 503          * It's assumed that $ns and $title are *valid*, for instance when
 504          * they came directly from the database or a special page name.
 505          * For convenience, spaces are converted to underscores so that
 506          * eg user_text fields can be used directly.
 507          *
 508          * @param int $ns The namespace of the article
 509          * @param string $title The unprefixed database key form
 510          * @param string $fragment The link fragment (after the "#")
 511          * @param string $interwiki The interwiki prefix
 512          * @return Title The new object
 513          */
 514         public static function makeTitle( $ns, $title, $fragment = '', $interwiki = '' ) {
 515                 $t = new Title();
 516                 $t->mInterwiki = $interwiki;
 517                 $t->mFragment = $fragment;
 518                 $t->mNamespace = $ns = intval( $ns );
 519                 $t->mDbkeyform = strtr( $title, ' ', '_' );
 520                 $t->mArticleID = ( $ns >= 0 ) ? -1 : 0;
 521                 $t->mUrlform = wfUrlencode( $t->mDbkeyform );
 522                 $t->mTextform = strtr( $title, '_', ' ' );
 523                 $t->mContentModel = false; # initialized lazily in getContentModel()
 524                 return $t;
 525         }
 526
 527         /**
 528          * Create a new Title from a namespace index and a DB key.
 529          * The parameters will be checked for validity, which is a bit slower
 530          * than makeTitle() but safer for user-provided data.
 531          *
 532          * @param int $ns The namespace of the article
 533          * @param string $title Database key form
 534          * @param string $fragment The link fragment (after the "#")
 535          * @param string $interwiki Interwiki prefix
 536          * @return Title|null The new object, or null on an error
 537          */
 538         public static function makeTitleSafe( $ns, $title, $fragment = '', $interwiki = '' ) {
 539                 if ( !MWNamespace::exists( $ns ) ) {
 540                         return null;
 541                 }
 542
 543                 $t = new Title();
 544                 $t->mDbkeyform = Title::makeName( $ns, $title, $fragment, $interwiki, true );
 545
 546                 try {
 547                         $t->secureAndSplit();
 548                         return $t;
 549                 } catch ( MalformedTitleException $ex ) {
 550                         return null;
 551                 }
 552         }
 553
 554         /**
 555          * Create a new Title for the Main Page
 556          *
 557          * @return Title The new object
 558          */
 559         public static function newMainPage() {
 560                 $title = Title::newFromText( wfMessage( 'mainpage' )->inContentLanguage()->text() );
 561                 // Don't give fatal errors if the message is broken
 562                 if ( !$title ) {
 563                         $title = Title::newFromText( 'Main Page' );
 564                 }
 565                 return $title;
 566         }
 567
 568         /**
 569          * Get the prefixed DB key associated with an ID
 570          *
 571          * @param int $id The page_id of the article
 572          * @return Title|null An object representing the article, or null if no such article was found
 573          */
 574         public static function nameOf( $id ) {
 575                 $dbr = wfGetDB( DB_REPLICA );
 576
 577                 $s = $dbr->selectRow(
 578                         'page',
 579                         [ 'page_namespace', 'page_title' ],
 580                         [ 'page_id' => $id ],
 581                         __METHOD__
 582                 );
 583                 if ( $s === false ) {
 584                         return null;
 585                 }
 586
 587                 $n = self::makeName( $s->page_namespace, $s->page_title );
 588                 return $n;
 589         }
 590
 591         /**
 592          * Get a regex character class describing the legal characters in a link
 593          *
 594          * @return string The list of characters, not delimited
 595          */
 596         public static function legalChars() {
 597                 global $wgLegalTitleChars;
 598                 return $wgLegalTitleChars;
 599         }
 600
 601         /**
 602          * Returns a simple regex that will match on characters and sequences invalid in titles.
 603          * Note that this doesn't pick up many things that could be wrong with titles, but that
 604          * replacing this regex with something valid will make many titles valid.
 605          *
 606          * @deprecated since 1.25, use MediaWikiTitleCodec::getTitleInvalidRegex() instead
 607          *
 608          * @return string Regex string
 609          */
 610         static function getTitleInvalidRegex() {
 611                 wfDeprecated( __METHOD__, '1.25' );
 612                 return MediaWikiTitleCodec::getTitleInvalidRegex();
 613         }
 614
 615         /**
 616          * Utility method for converting a character sequence from bytes to Unicode.
 617          *
 618          * Primary usecase being converting $wgLegalTitleChars to a sequence usable in
 619          * javascript, as PHP uses UTF-8 bytes where javascript uses Unicode code units.
 620          *
 621          * @param string $byteClass
 622          * @return string
 623          */
 624         public static function convertByteClassToUnicodeClass( $byteClass ) {
 625                 $length = strlen( $byteClass );
 626                 // Input token queue
 627                 $x0 = $x1 = $x2 = '';
 628                 // Decoded queue
 629                 $d0 = $d1 = $d2 = '';
 630                 // Decoded integer codepoints
 631                 $ord0 = $ord1 = $ord2 = 0;
 632                 // Re-encoded queue
 633                 $r0 = $r1 = $r2 = '';
 634                 // Output
 635                 $out = '';
 636                 // Flags
 637                 $allowUnicode = false;
 638                 for ( $pos = 0; $pos < $length; $pos++ ) {
 639                         // Shift the queues down
 640                         $x2 = $x1;
 641                         $x1 = $x0;
 642                         $d2 = $d1;
 643                         $d1 = $d0;
 644                         $ord2 = $ord1;
 645                         $ord1 = $ord0;
 646                         $r2 = $r1;
 647                         $r1 = $r0;
 648                         // Load the current input token and decoded values
 649                         $inChar = $byteClass[$pos];
 650                         if ( $inChar == '\\' ) {
 651                                 if ( preg_match( '/x([0-9a-fA-F]{2})/A', $byteClass, $m, 0, $pos + 1 ) ) {
 652                                         $x0 = $inChar . $m[0];
 653                                         $d0 = chr( hexdec( $m[1] ) );
 654                                         $pos += strlen( $m[0] );
 655                                 } elseif ( preg_match( '/[0-7]{3}/A', $byteClass, $m, 0, $pos + 1 ) ) {
 656                                         $x0 = $inChar . $m[0];
 657                                         $d0 = chr( octdec( $m[0] ) );
 658                                         $pos += strlen( $m[0] );
 659                                 } elseif ( $pos + 1 >= $length ) {
 660                                         $x0 = $d0 = '\\';
 661                                 } else {
 662                                         $d0 = $byteClass[$pos + 1];
 663                                         $x0 = $inChar . $d0;
 664                                         $pos += 1;
 665                                 }
 666                         } else {
 667                                 $x0 = $d0 = $inChar;
 668                         }
 669                         $ord0 = ord( $d0 );
 670                         // Load the current re-encoded value
 671                         if ( $ord0 < 32 || $ord0 == 0x7f ) {
 672                                 $r0 = sprintf( '\x%02x', $ord0 );
 673                         } elseif ( $ord0 >= 0x80 ) {
 674                                 // Allow unicode if a single high-bit character appears
 675                                 $r0 = sprintf( '\x%02x', $ord0 );
 676                                 $allowUnicode = true;
 677                         } elseif ( strpos( '-\\[]^', $d0 ) !== false ) {
 678                                 $r0 = '\\' . $d0;
 679                         } else {
 680                                 $r0 = $d0;
 681                         }
 682                         // Do the output
 683                         if ( $x0 !== '' && $x1 === '-' && $x2 !== '' ) {
 684                                 // Range
 685                                 if ( $ord2 > $ord0 ) {
 686                                         // Empty range
 687                                 } elseif ( $ord0 >= 0x80 ) {
 688                                         // Unicode range
 689                                         $allowUnicode = true;
 690                                         if ( $ord2 < 0x80 ) {
 691                                                 // Keep the non-unicode section of the range
 692                                                 $out .= "$r2-\\x7F";
 693                                         }
 694                                 } else {
 695                                         // Normal range
 696                                         $out .= "$r2-$r0";
 697                                 }
 698                                 // Reset state to the initial value
 699                                 $x0 = $x1 = $d0 = $d1 = $r0 = $r1 = '';
 700                         } elseif ( $ord2 < 0x80 ) {
 701                                 // ASCII character
 702                                 $out .= $r2;
 703                         }
 704                 }
 705                 if ( $ord1 < 0x80 ) {
 706                         $out .= $r1;
 707                 }
 708                 if ( $ord0 < 0x80 ) {
 709                         $out .= $r0;
 710                 }
 711                 if ( $allowUnicode ) {
 712                         $out .= '\u0080-\uFFFF';
 713                 }
 714                 return $out;
 715         }
 716
 717         /**
 718          * Make a prefixed DB key from a DB key and a namespace index
 719          *
 720          * @param int $ns Numerical representation of the namespace
 721          * @param string $title The DB key form the title
 722          * @param string $fragment The link fragment (after the "#")
 723          * @param string $interwiki The interwiki prefix
 724          * @param bool $canonicalNamespace If true, use the canonical name for
 725          *   $ns instead of the localized version.
 726          * @return string The prefixed form of the title
 727          */
 728         public static function makeName( $ns, $title, $fragment = '', $interwiki = '',
 729                 $canonicalNamespace = false
 730         ) {
 731                 global $wgContLang;
 732
 733                 if ( $canonicalNamespace ) {
 734                         $namespace = MWNamespace::getCanonicalName( $ns );
 735                 } else {
 736                         $namespace = $wgContLang->getNsText( $ns );
 737                 }
 738                 $name = $namespace == '' ? $title : "$namespace:$title";
 739                 if ( strval( $interwiki ) != '' ) {
 740                         $name = "$interwiki:$name";
 741                 }
 742                 if ( strval( $fragment ) != '' ) {
 743                         $name .= '#' . $fragment;
 744                 }
 745                 return $name;
 746         }
 747
 748         /**
 749          * Escape a text fragment, say from a link, for a URL
 750          *
 751          * @param string $fragment Containing a URL or link fragment (after the "#")
 752          * @return string Escaped string
 753          */
 754         static function escapeFragmentForURL( $fragment ) {
 755                 # Note that we don't urlencode the fragment.  urlencoded Unicode
 756                 # fragments appear not to work in IE (at least up to 7) or in at least
 757                 # one version of Opera 9.x.  The W3C validator, for one, doesn't seem
 758                 # to care if they aren't encoded.
 759                 return Sanitizer::escapeId( $fragment, 'noninitial' );
 760         }
 761
 762         /**
 763          * Callback for usort() to do title sorts by (namespace, title)
 764          *
 765          * @param LinkTarget $a
 766          * @param LinkTarget $b
 767          *
 768          * @return int Result of string comparison, or namespace comparison
 769          */
 770         public static function compare( LinkTarget $a, LinkTarget $b ) {
 771                 if ( $a->getNamespace() == $b->getNamespace() ) {
 772                         return strcmp( $a->getText(), $b->getText() );
 773                 } else {
 774                         return $a->getNamespace() - $b->getNamespace();
 775                 }
 776         }
 777
 778         /**
 779          * Determine whether the object refers to a page within
 780          * this project (either this wiki or a wiki with a local
 781          * interwiki, see https://www.mediawiki.org/wiki/Manual:Interwiki_table#iw_local )
 782          *
 783          * @return bool True if this is an in-project interwiki link or a wikilink, false otherwise
 784          */
 785         public function isLocal() {
 786                 if ( $this->isExternal() ) {
 787                         $iw = self::getInterwikiLookup()->fetch( $this->mInterwiki );
 788                         if ( $iw ) {
 789                                 return $iw->isLocal();
 790                         }
 791                 }
 792                 return true;
 793         }
 794
 795         /**
 796          * Is this Title interwiki?
 797          *
 798          * @return bool
 799          */
 800         public function isExternal() {
 801                 return $this->mInterwiki !== '';
 802         }
 803
 804         /**
 805          * Get the interwiki prefix
 806          *
 807          * Use Title::isExternal to check if a interwiki is set
 808          *
 809          * @return string Interwiki prefix
 810          */
 811         public function getInterwiki() {
 812                 return $this->mInterwiki;
 813         }
 814
 815         /**
 816          * Was this a local interwiki link?
 817          *
 818          * @return bool
 819          */
 820         public function wasLocalInterwiki() {
 821                 return $this->mLocalInterwiki;
 822         }
 823
 824         /**
 825          * Determine whether the object refers to a page within
 826          * this project and is transcludable.
 827          *
 828          * @return bool True if this is transcludable
 829          */
 830         public function isTrans() {
 831                 if ( !$this->isExternal() ) {
 832                         return false;
 833                 }
 834
 835                 return self::getInterwikiLookup()->fetch( $this->mInterwiki )->isTranscludable();
 836         }
 837
 838         /**
 839          * Returns the DB name of the distant wiki which owns the object.
 840          *
 841          * @return string|false The DB name
 842          */
 843         public function getTransWikiID() {
 844                 if ( !$this->isExternal() ) {
 845                         return false;
 846                 }
 847
 848                 return self::getInterwikiLookup()->fetch( $this->mInterwiki )->getWikiID();
 849         }
 850
 851         /**
 852          * Get a TitleValue object representing this Title.
 853          *
 854          * @note Not all valid Titles have a corresponding valid TitleValue
 855          * (e.g. TitleValues cannot represent page-local links that have a
 856          * fragment but no title text).
 857          *
 858          * @return TitleValue|null
 859          */
 860         public function getTitleValue() {
 861                 if ( $this->mTitleValue === null ) {
 862                         try {
 863                                 $this->mTitleValue = new TitleValue(
 864                                         $this->getNamespace(),
 865                                         $this->getDBkey(),
 866                                         $this->getFragment(),
 867                                         $this->getInterwiki()
 868                                 );
 869                         } catch ( InvalidArgumentException $ex ) {
 870                                 wfDebug( __METHOD__ . ': Can\'t create a TitleValue for [[' .
 871                                         $this->getPrefixedText() . ']]: ' . $ex->getMessage() . "\n" );
 872                         }
 873                 }
 874
 875                 return $this->mTitleValue;
 876         }
 877
 878         /**
 879          * Get the text form (spaces not underscores) of the main part
 880          *
 881          * @return string Main part of the title
 882          */
 883         public function getText() {
 884                 return $this->mTextform;
 885         }
 886
 887         /**
 888          * Get the URL-encoded form of the main part
 889          *
 890          * @return string Main part of the title, URL-encoded
 891          */
 892         public function getPartialURL() {
 893                 return $this->mUrlform;
 894         }
 895
 896         /**
 897          * Get the main part with underscores
 898          *
 899          * @return string Main part of the title, with underscores
 900          */
 901         public function getDBkey() {
 902                 return $this->mDbkeyform;
 903         }
 904
 905         /**
 906          * Get the DB key with the initial letter case as specified by the user
 907          *
 908          * @return string DB key
 909          */
 910         function getUserCaseDBKey() {
 911                 if ( !is_null( $this->mUserCaseDBKey ) ) {
 912                         return $this->mUserCaseDBKey;
 913                 } else {
 914                         // If created via makeTitle(), $this->mUserCaseDBKey is not set.
 915                         return $this->mDbkeyform;
 916                 }
 917         }
 918
 919         /**
 920          * Get the namespace index, i.e. one of the NS_xxxx constants.
 921          *
 922          * @return int Namespace index
 923          */
 924         public function getNamespace() {
 925                 return $this->mNamespace;
 926         }
 927
 928         /**
 929          * Get the page's content model id, see the CONTENT_MODEL_XXX constants.
 930          *
 931          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
 932          * @return string Content model id
 933          */
 934         public function getContentModel( $flags = 0 ) {
 935                 if ( !$this->mForcedContentModel
 936                         && ( !$this->mContentModel || $flags === Title::GAID_FOR_UPDATE )
 937                         && $this->getArticleID( $flags )
 938                 ) {
 939                         $linkCache = LinkCache::singleton();
 940                         $linkCache->addLinkObj( $this ); # in case we already had an article ID
 941                         $this->mContentModel = $linkCache->getGoodLinkFieldObj( $this, 'model' );
 942                 }
 943
 944                 if ( !$this->mContentModel ) {
 945                         $this->mContentModel = ContentHandler::getDefaultModelFor( $this );
 946                 }
 947
 948                 return $this->mContentModel;
 949         }
 950
 951         /**
 952          * Convenience method for checking a title's content model name
 953          *
 954          * @param string $id The content model ID (use the CONTENT_MODEL_XXX constants).
 955          * @return bool True if $this->getContentModel() == $id
 956          */
 957         public function hasContentModel( $id ) {
 958                 return $this->getContentModel() == $id;
 959         }
 960
 961         /**
 962          * Set a proposed content model for the page for permissions
 963          * checking. This does not actually change the content model
 964          * of a title!
 965          *
 966          * Additionally, you should make sure you've checked
 967          * ContentHandler::canBeUsedOn() first.
 968          *
 969          * @since 1.28
 970          * @param string $model CONTENT_MODEL_XXX constant
 971          */
 972         public function setContentModel( $model ) {
 973                 $this->mContentModel = $model;
 974                 $this->mForcedContentModel = true;
 975         }
 976
 977         /**
 978          * Get the namespace text
 979          *
 980          * @return string|false Namespace text
 981          */
 982         public function getNsText() {
 983                 if ( $this->isExternal() ) {
 984                         // This probably shouldn't even happen,
 985                         // but for interwiki transclusion it sometimes does.
 986                         // Use the canonical namespaces if possible to try to
 987                         // resolve a foreign namespace.
 988                         if ( MWNamespace::exists( $this->mNamespace ) ) {
 989                                 return MWNamespace::getCanonicalName( $this->mNamespace );
 990                         }
 991                 }
 992
 993                 try {
 994                         $formatter = self::getTitleFormatter();
 995                         return $formatter->getNamespaceName( $this->mNamespace, $this->mDbkeyform );
 996                 } catch ( InvalidArgumentException $ex ) {
 997                         wfDebug( __METHOD__ . ': ' . $ex->getMessage() . "\n" );
 998                         return false;
 999                 }
1000         }
1001
1002         /**
1003          * Get the namespace text of the subject (rather than talk) page
1004          *
1005          * @return string Namespace text
1006          */
1007         public function getSubjectNsText() {
1008                 global $wgContLang;
1009                 return $wgContLang->getNsText( MWNamespace::getSubject( $this->mNamespace ) );
1010         }
1011
1012         /**
1013          * Get the namespace text of the talk page
1014          *
1015          * @return string Namespace text
1016          */
1017         public function getTalkNsText() {
1018                 global $wgContLang;
1019                 return $wgContLang->getNsText( MWNamespace::getTalk( $this->mNamespace ) );
1020         }
1021
1022         /**
1023          * 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 Title::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( Title::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 Title::makeTitle( MWNamespace::getTalk( $this->getNamespace() ), $this->getDBkey() );
1317         }
1318
1319         /**
1320          * Get a title object associated with the subject page of this
1321          * talk page
1322          *
1323          * @return Title The object for the subject page
1324          */
1325         public function getSubjectPage() {
1326                 // Is this the same title?
1327                 $subjectNS = MWNamespace::getSubject( $this->getNamespace() );
1328                 if ( $this->getNamespace() == $subjectNS ) {
1329                         return $this;
1330                 }
1331                 return Title::makeTitle( $subjectNS, $this->getDBkey() );
1332         }
1333
1334         /**
1335          * Get the other title for this page, if this is a subject page
1336          * get the talk page, if it is a subject page get the talk page
1337          *
1338          * @since 1.25
1339          * @throws MWException
1340          * @return Title
1341          */
1342         public function getOtherPage() {
1343                 if ( $this->isSpecialPage() ) {
1344                         throw new MWException( 'Special pages cannot have other pages' );
1345                 }
1346                 if ( $this->isTalkPage() ) {
1347                         return $this->getSubjectPage();
1348                 } else {
1349                         return $this->getTalkPage();
1350                 }
1351         }
1352
1353         /**
1354          * Get the default namespace index, for when there is no namespace
1355          *
1356          * @return int Default namespace index
1357          */
1358         public function getDefaultNamespace() {
1359                 return $this->mDefaultNamespace;
1360         }
1361
1362         /**
1363          * Get the Title fragment (i.e.\ the bit after the #) in text form
1364          *
1365          * Use Title::hasFragment to check for a fragment
1366          *
1367          * @return string Title fragment
1368          */
1369         public function getFragment() {
1370                 return $this->mFragment;
1371         }
1372
1373         /**
1374          * Check if a Title fragment is set
1375          *
1376          * @return bool
1377          * @since 1.23
1378          */
1379         public function hasFragment() {
1380                 return $this->mFragment !== '';
1381         }
1382
1383         /**
1384          * Get the fragment in URL form, including the "#" character if there is one
1385          * @return string Fragment in URL form
1386          */
1387         public function getFragmentForURL() {
1388                 if ( !$this->hasFragment() ) {
1389                         return '';
1390                 } else {
1391                         return '#' . Title::escapeFragmentForURL( $this->getFragment() );
1392                 }
1393         }
1394
1395         /**
1396          * Set the fragment for this title. Removes the first character from the
1397          * specified fragment before setting, so it assumes you're passing it with
1398          * an initial "#".
1399          *
1400          * Deprecated for public use, use Title::makeTitle() with fragment parameter,
1401          * or Title::createFragmentTarget().
1402          * Still in active use privately.
1403          *
1404          * @private
1405          * @param string $fragment Text
1406          */
1407         public function setFragment( $fragment ) {
1408                 $this->mFragment = strtr( substr( $fragment, 1 ), '_', ' ' );
1409         }
1410
1411         /**
1412          * Creates a new Title for a different fragment of the same page.
1413          *
1414          * @since 1.27
1415          * @param string $fragment
1416          * @return Title
1417          */
1418         public function createFragmentTarget( $fragment ) {
1419                 return self::makeTitle(
1420                         $this->getNamespace(),
1421                         $this->getText(),
1422                         $fragment,
1423                         $this->getInterwiki()
1424                 );
1425         }
1426
1427         /**
1428          * Prefix some arbitrary text with the namespace or interwiki prefix
1429          * of this object
1430          *
1431          * @param string $name The text
1432          * @return string The prefixed text
1433          */
1434         private function prefix( $name ) {
1435                 global $wgContLang;
1436
1437                 $p = '';
1438                 if ( $this->isExternal() ) {
1439                         $p = $this->mInterwiki . ':';
1440                 }
1441
1442                 if ( 0 != $this->mNamespace ) {
1443                         $nsText = $this->getNsText();
1444
1445                         if ( $nsText === false ) {
1446                                 // See T165149. Awkward, but better than erroneously linking to the main namespace.
1447                                 $nsText = $wgContLang->getNsText( NS_SPECIAL ) . ":Badtitle/NS{$this->mNamespace}";
1448                         }
1449
1450                         $p .= $nsText . ':';
1451                 }
1452                 return $p . $name;
1453         }
1454
1455         /**
1456          * Get the prefixed database key form
1457          *
1458          * @return string The prefixed title, with underscores and
1459          *  any interwiki and namespace prefixes
1460          */
1461         public function getPrefixedDBkey() {
1462                 $s = $this->prefix( $this->mDbkeyform );
1463                 $s = strtr( $s, ' ', '_' );
1464                 return $s;
1465         }
1466
1467         /**
1468          * Get the prefixed title with spaces.
1469          * This is the form usually used for display
1470          *
1471          * @return string The prefixed title, with spaces
1472          */
1473         public function getPrefixedText() {
1474                 if ( $this->mPrefixedText === null ) {
1475                         $s = $this->prefix( $this->mTextform );
1476                         $s = strtr( $s, '_', ' ' );
1477                         $this->mPrefixedText = $s;
1478                 }
1479                 return $this->mPrefixedText;
1480         }
1481
1482         /**
1483          * Return a string representation of this title
1484          *
1485          * @return string Representation of this title
1486          */
1487         public function __toString() {
1488                 return $this->getPrefixedText();
1489         }
1490
1491         /**
1492          * Get the prefixed title with spaces, plus any fragment
1493          * (part beginning with '#')
1494          *
1495          * @return string The prefixed title, with spaces and the fragment, including '#'
1496          */
1497         public function getFullText() {
1498                 $text = $this->getPrefixedText();
1499                 if ( $this->hasFragment() ) {
1500                         $text .= '#' . $this->getFragment();
1501                 }
1502                 return $text;
1503         }
1504
1505         /**
1506          * Get the root page name text without a namespace, i.e. the leftmost part before any slashes
1507          *
1508          * @par Example:
1509          * @code
1510          * Title::newFromText('User:Foo/Bar/Baz')->getRootText();
1511          * # returns: 'Foo'
1512          * @endcode
1513          *
1514          * @return string Root name
1515          * @since 1.20
1516          */
1517         public function getRootText() {
1518                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1519                         return $this->getText();
1520                 }
1521
1522                 return strtok( $this->getText(), '/' );
1523         }
1524
1525         /**
1526          * Get the root page name title, i.e. the leftmost part before any slashes
1527          *
1528          * @par Example:
1529          * @code
1530          * Title::newFromText('User:Foo/Bar/Baz')->getRootTitle();
1531          * # returns: Title{User:Foo}
1532          * @endcode
1533          *
1534          * @return Title Root title
1535          * @since 1.20
1536          */
1537         public function getRootTitle() {
1538                 return Title::makeTitle( $this->getNamespace(), $this->getRootText() );
1539         }
1540
1541         /**
1542          * Get the base page name without a namespace, i.e. the part before the subpage name
1543          *
1544          * @par Example:
1545          * @code
1546          * Title::newFromText('User:Foo/Bar/Baz')->getBaseText();
1547          * # returns: 'Foo/Bar'
1548          * @endcode
1549          *
1550          * @return string Base name
1551          */
1552         public function getBaseText() {
1553                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1554                         return $this->getText();
1555                 }
1556
1557                 $parts = explode( '/', $this->getText() );
1558                 # Don't discard the real title if there's no subpage involved
1559                 if ( count( $parts ) > 1 ) {
1560                         unset( $parts[count( $parts ) - 1] );
1561                 }
1562                 return implode( '/', $parts );
1563         }
1564
1565         /**
1566          * Get the base page name title, i.e. the part before the subpage name
1567          *
1568          * @par Example:
1569          * @code
1570          * Title::newFromText('User:Foo/Bar/Baz')->getBaseTitle();
1571          * # returns: Title{User:Foo/Bar}
1572          * @endcode
1573          *
1574          * @return Title Base title
1575          * @since 1.20
1576          */
1577         public function getBaseTitle() {
1578                 return Title::makeTitle( $this->getNamespace(), $this->getBaseText() );
1579         }
1580
1581         /**
1582          * Get the lowest-level subpage name, i.e. the rightmost part after any slashes
1583          *
1584          * @par Example:
1585          * @code
1586          * Title::newFromText('User:Foo/Bar/Baz')->getSubpageText();
1587          * # returns: "Baz"
1588          * @endcode
1589          *
1590          * @return string Subpage name
1591          */
1592         public function getSubpageText() {
1593                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1594                         return $this->mTextform;
1595                 }
1596                 $parts = explode( '/', $this->mTextform );
1597                 return $parts[count( $parts ) - 1];
1598         }
1599
1600         /**
1601          * Get the title for a subpage of the current page
1602          *
1603          * @par Example:
1604          * @code
1605          * Title::newFromText('User:Foo/Bar/Baz')->getSubpage("Asdf");
1606          * # returns: Title{User:Foo/Bar/Baz/Asdf}
1607          * @endcode
1608          *
1609          * @param string $text The subpage name to add to the title
1610          * @return Title Subpage title
1611          * @since 1.20
1612          */
1613         public function getSubpage( $text ) {
1614                 return Title::makeTitleSafe( $this->getNamespace(), $this->getText() . '/' . $text );
1615         }
1616
1617         /**
1618          * Get a URL-encoded form of the subpage text
1619          *
1620          * @return string URL-encoded subpage name
1621          */
1622         public function getSubpageUrlForm() {
1623                 $text = $this->getSubpageText();
1624                 $text = wfUrlencode( strtr( $text, ' ', '_' ) );
1625                 return $text;
1626         }
1627
1628         /**
1629          * Get a URL-encoded title (not an actual URL) including interwiki
1630          *
1631          * @return string The URL-encoded form
1632          */
1633         public function getPrefixedURL() {
1634                 $s = $this->prefix( $this->mDbkeyform );
1635                 $s = wfUrlencode( strtr( $s, ' ', '_' ) );
1636                 return $s;
1637         }
1638
1639         /**
1640          * Helper to fix up the get{Canonical,Full,Link,Local,Internal}URL args
1641          * get{Canonical,Full,Link,Local,Internal}URL methods accepted an optional
1642          * second argument named variant. This was deprecated in favor
1643          * of passing an array of option with a "variant" key
1644          * Once $query2 is removed for good, this helper can be dropped
1645          * and the wfArrayToCgi moved to getLocalURL();
1646          *
1647          * @since 1.19 (r105919)
1648          * @param array|string $query
1649          * @param string|string[]|bool $query2
1650          * @return string
1651          */
1652         private static function fixUrlQueryArgs( $query, $query2 = false ) {
1653                 if ( $query2 !== false ) {
1654                         wfDeprecated( "Title::get{Canonical,Full,Link,Local,Internal}URL " .
1655                                 "method called with a second parameter is deprecated. Add your " .
1656                                 "parameter to an array passed as the first parameter.", "1.19" );
1657                 }
1658                 if ( is_array( $query ) ) {
1659                         $query = wfArrayToCgi( $query );
1660                 }
1661                 if ( $query2 ) {
1662                         if ( is_string( $query2 ) ) {
1663                                 // $query2 is a string, we will consider this to be
1664                                 // a deprecated $variant argument and add it to the query
1665                                 $query2 = wfArrayToCgi( [ 'variant' => $query2 ] );
1666                         } else {
1667                                 $query2 = wfArrayToCgi( $query2 );
1668                         }
1669                         // If we have $query content add a & to it first
1670                         if ( $query ) {
1671                                 $query .= '&';
1672                         }
1673                         // Now append the queries together
1674                         $query .= $query2;
1675                 }
1676                 return $query;
1677         }
1678
1679         /**
1680          * Get a real URL referring to this title, with interwiki link and
1681          * fragment
1682          *
1683          * @see self::getLocalURL for the arguments.
1684          * @see wfExpandUrl
1685          * @param string|string[] $query
1686          * @param string|string[]|bool $query2
1687          * @param string $proto Protocol type to use in URL
1688          * @return string The URL
1689          */
1690         public function getFullURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1691                 $query = self::fixUrlQueryArgs( $query, $query2 );
1692
1693                 # Hand off all the decisions on urls to getLocalURL
1694                 $url = $this->getLocalURL( $query );
1695
1696                 # Expand the url to make it a full url. Note that getLocalURL has the
1697                 # potential to output full urls for a variety of reasons, so we use
1698                 # wfExpandUrl instead of simply prepending $wgServer
1699                 $url = wfExpandUrl( $url, $proto );
1700
1701                 # Finally, add the fragment.
1702                 $url .= $this->getFragmentForURL();
1703                 // Avoid PHP 7.1 warning from passing $this by reference
1704                 $titleRef = $this;
1705                 Hooks::run( 'GetFullURL', [ &$titleRef, &$url, $query ] );
1706                 return $url;
1707         }
1708
1709         /**
1710          * Get a url appropriate for making redirects based on an untrusted url arg
1711          *
1712          * This is basically the same as getFullUrl(), but in the case of external
1713          * interwikis, we send the user to a landing page, to prevent possible
1714          * phishing attacks and the like.
1715          *
1716          * @note Uses current protocol by default, since technically relative urls
1717          *   aren't allowed in redirects per HTTP spec, so this is not suitable for
1718          *   places where the url gets cached, as might pollute between
1719          *   https and non-https users.
1720          * @see self::getLocalURL for the arguments.
1721          * @param array|string $query
1722          * @param string $proto Protocol type to use in URL
1723          * @return String. A url suitable to use in an HTTP location header.
1724          */
1725         public function getFullUrlForRedirect( $query = '', $proto = PROTO_CURRENT ) {
1726                 $target = $this;
1727                 if ( $this->isExternal() ) {
1728                         $target = SpecialPage::getTitleFor(
1729                                 'GoToInterwiki',
1730                                 $this->getPrefixedDBKey()
1731                         );
1732                 }
1733                 return $target->getFullUrl( $query, false, $proto );
1734         }
1735
1736         /**
1737          * Get a URL with no fragment or server name (relative URL) from a Title object.
1738          * If this page is generated with action=render, however,
1739          * $wgServer is prepended to make an absolute URL.
1740          *
1741          * @see self::getFullURL to always get an absolute URL.
1742          * @see self::getLinkURL to always get a URL that's the simplest URL that will be
1743          *  valid to link, locally, to the current Title.
1744          * @see self::newFromText to produce a Title object.
1745          *
1746          * @param string|string[] $query An optional query string,
1747          *   not used for interwiki links. Can be specified as an associative array as well,
1748          *   e.g., array( 'action' => 'edit' ) (keys and values will be URL-escaped).
1749          *   Some query patterns will trigger various shorturl path replacements.
1750          * @param string|string[]|bool $query2 An optional secondary query array. This one MUST
1751          *   be an array. If a string is passed it will be interpreted as a deprecated
1752          *   variant argument and urlencoded into a variant= argument.
1753          *   This second query argument will be added to the $query
1754          *   The second parameter is deprecated since 1.19. Pass it as a key,value
1755          *   pair in the first parameter array instead.
1756          *
1757          * @return string String of the URL.
1758          */
1759         public function getLocalURL( $query = '', $query2 = false ) {
1760                 global $wgArticlePath, $wgScript, $wgServer, $wgRequest;
1761
1762                 $query = self::fixUrlQueryArgs( $query, $query2 );
1763
1764                 $interwiki = self::getInterwikiLookup()->fetch( $this->mInterwiki );
1765                 if ( $interwiki ) {
1766                         $namespace = $this->getNsText();
1767                         if ( $namespace != '' ) {
1768                                 # Can this actually happen? Interwikis shouldn't be parsed.
1769                                 # Yes! It can in interwiki transclusion. But... it probably shouldn't.
1770                                 $namespace .= ':';
1771                         }
1772                         $url = $interwiki->getURL( $namespace . $this->getDBkey() );
1773                         $url = wfAppendQuery( $url, $query );
1774                 } else {
1775                         $dbkey = wfUrlencode( $this->getPrefixedDBkey() );
1776                         if ( $query == '' ) {
1777                                 $url = str_replace( '$1', $dbkey, $wgArticlePath );
1778                                 // Avoid PHP 7.1 warning from passing $this by reference
1779                                 $titleRef = $this;
1780                                 Hooks::run( 'GetLocalURL::Article', [ &$titleRef, &$url ] );
1781                         } else {
1782                                 global $wgVariantArticlePath, $wgActionPaths, $wgContLang;
1783                                 $url = false;
1784                                 $matches = [];
1785
1786                                 if ( !empty( $wgActionPaths )
1787                                         && preg_match( '/^(.*&|)action=([^&]*)(&(.*)|)$/', $query, $matches )
1788                                 ) {
1789                                         $action = urldecode( $matches[2] );
1790                                         if ( isset( $wgActionPaths[$action] ) ) {
1791                                                 $query = $matches[1];
1792                                                 if ( isset( $matches[4] ) ) {
1793                                                         $query .= $matches[4];
1794                                                 }
1795                                                 $url = str_replace( '$1', $dbkey, $wgActionPaths[$action] );
1796                                                 if ( $query != '' ) {
1797                                                         $url = wfAppendQuery( $url, $query );
1798                                                 }
1799                                         }
1800                                 }
1801
1802                                 if ( $url === false
1803                                         && $wgVariantArticlePath
1804                                         && preg_match( '/^variant=([^&]*)$/', $query, $matches )
1805                                         && $this->getPageLanguage()->equals( $wgContLang )
1806                                         && $this->getPageLanguage()->hasVariants()
1807                                 ) {
1808                                         $variant = urldecode( $matches[1] );
1809                                         if ( $this->getPageLanguage()->hasVariant( $variant ) ) {
1810                                                 // Only do the variant replacement if the given variant is a valid
1811                                                 // variant for the page's language.
1812                                                 $url = str_replace( '$2', urlencode( $variant ), $wgVariantArticlePath );
1813                                                 $url = str_replace( '$1', $dbkey, $url );
1814                                         }
1815                                 }
1816
1817                                 if ( $url === false ) {
1818                                         if ( $query == '-' ) {
1819                                                 $query = '';
1820                                         }
1821                                         $url = "{$wgScript}?title={$dbkey}&{$query}";
1822                                 }
1823                         }
1824                         // Avoid PHP 7.1 warning from passing $this by reference
1825                         $titleRef = $this;
1826                         Hooks::run( 'GetLocalURL::Internal', [ &$titleRef, &$url, $query ] );
1827
1828                         // @todo FIXME: This causes breakage in various places when we
1829                         // actually expected a local URL and end up with dupe prefixes.
1830                         if ( $wgRequest->getVal( 'action' ) == 'render' ) {
1831                                 $url = $wgServer . $url;
1832                         }
1833                 }
1834                 // Avoid PHP 7.1 warning from passing $this by reference
1835                 $titleRef = $this;
1836                 Hooks::run( 'GetLocalURL', [ &$titleRef, &$url, $query ] );
1837                 return $url;
1838         }
1839
1840         /**
1841          * Get a URL that's the simplest URL that will be valid to link, locally,
1842          * to the current Title.  It includes the fragment, but does not include
1843          * the server unless action=render is used (or the link is external).  If
1844          * there's a fragment but the prefixed text is empty, we just return a link
1845          * to the fragment.
1846          *
1847          * The result obviously should not be URL-escaped, but does need to be
1848          * HTML-escaped if it's being output in HTML.
1849          *
1850          * @param string|string[] $query
1851          * @param bool $query2
1852          * @param string|int|bool $proto A PROTO_* constant on how the URL should be expanded,
1853          *                               or false (default) for no expansion
1854          * @see self::getLocalURL for the arguments.
1855          * @return string The URL
1856          */
1857         public function getLinkURL( $query = '', $query2 = false, $proto = false ) {
1858                 if ( $this->isExternal() || $proto !== false ) {
1859                         $ret = $this->getFullURL( $query, $query2, $proto );
1860                 } elseif ( $this->getPrefixedText() === '' && $this->hasFragment() ) {
1861                         $ret = $this->getFragmentForURL();
1862                 } else {
1863                         $ret = $this->getLocalURL( $query, $query2 ) . $this->getFragmentForURL();
1864                 }
1865                 return $ret;
1866         }
1867
1868         /**
1869          * Get the URL form for an internal link.
1870          * - Used in various CDN-related code, in case we have a different
1871          * internal hostname for the server from the exposed one.
1872          *
1873          * This uses $wgInternalServer to qualify the path, or $wgServer
1874          * if $wgInternalServer is not set. If the server variable used is
1875          * protocol-relative, the URL will be expanded to http://
1876          *
1877          * @see self::getLocalURL for the arguments.
1878          * @return string The URL
1879          */
1880         public function getInternalURL( $query = '', $query2 = false ) {
1881                 global $wgInternalServer, $wgServer;
1882                 $query = self::fixUrlQueryArgs( $query, $query2 );
1883                 $server = $wgInternalServer !== false ? $wgInternalServer : $wgServer;
1884                 $url = wfExpandUrl( $server . $this->getLocalURL( $query ), PROTO_HTTP );
1885                 // Avoid PHP 7.1 warning from passing $this by reference
1886                 $titleRef = $this;
1887                 Hooks::run( 'GetInternalURL', [ &$titleRef, &$url, $query ] );
1888                 return $url;
1889         }
1890
1891         /**
1892          * Get the URL for a canonical link, for use in things like IRC and
1893          * e-mail notifications. Uses $wgCanonicalServer and the
1894          * GetCanonicalURL hook.
1895          *
1896          * NOTE: Unlike getInternalURL(), the canonical URL includes the fragment
1897          *
1898          * @see self::getLocalURL for the arguments.
1899          * @return string The URL
1900          * @since 1.18
1901          */
1902         public function getCanonicalURL( $query = '', $query2 = false ) {
1903                 $query = self::fixUrlQueryArgs( $query, $query2 );
1904                 $url = wfExpandUrl( $this->getLocalURL( $query ) . $this->getFragmentForURL(), PROTO_CANONICAL );
1905                 // Avoid PHP 7.1 warning from passing $this by reference
1906                 $titleRef = $this;
1907                 Hooks::run( 'GetCanonicalURL', [ &$titleRef, &$url, $query ] );
1908                 return $url;
1909         }
1910
1911         /**
1912          * Get the edit URL for this Title
1913          *
1914          * @return string The URL, or a null string if this is an interwiki link
1915          */
1916         public function getEditURL() {
1917                 if ( $this->isExternal() ) {
1918                         return '';
1919                 }
1920                 $s = $this->getLocalURL( 'action=edit' );
1921
1922                 return $s;
1923         }
1924
1925         /**
1926          * Can $user perform $action on this page?
1927          * This skips potentially expensive cascading permission checks
1928          * as well as avoids expensive error formatting
1929          *
1930          * Suitable for use for nonessential UI controls in common cases, but
1931          * _not_ for functional access control.
1932          *
1933          * May provide false positives, but should never provide a false negative.
1934          *
1935          * @param string $action Action that permission needs to be checked for
1936          * @param User $user User to check (since 1.19); $wgUser will be used if not provided.
1937          * @return bool
1938          */
1939         public function quickUserCan( $action, $user = null ) {
1940                 return $this->userCan( $action, $user, false );
1941         }
1942
1943         /**
1944          * Can $user perform $action on this page?
1945          *
1946          * @param string $action Action that permission needs to be checked for
1947          * @param User $user User to check (since 1.19); $wgUser will be used if not
1948          *   provided.
1949          * @param string $rigor Same format as Title::getUserPermissionsErrors()
1950          * @return bool
1951          */
1952         public function userCan( $action, $user = null, $rigor = 'secure' ) {
1953                 if ( !$user instanceof User ) {
1954                         global $wgUser;
1955                         $user = $wgUser;
1956                 }
1957
1958                 return !count( $this->getUserPermissionsErrorsInternal( $action, $user, $rigor, true ) );
1959         }
1960
1961         /**
1962          * Can $user perform $action on this page?
1963          *
1964          * @todo FIXME: This *does not* check throttles (User::pingLimiter()).
1965          *
1966          * @param string $action Action that permission needs to be checked for
1967          * @param User $user User to check
1968          * @param string $rigor One of (quick,full,secure)
1969          *   - quick  : does cheap permission checks from replica DBs (usable for GUI creation)
1970          *   - full   : does cheap and expensive checks possibly from a replica DB
1971          *   - secure : does cheap and expensive checks, using the master as needed
1972          * @param array $ignoreErrors Array of Strings Set this to a list of message keys
1973          *   whose corresponding errors may be ignored.
1974          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
1975          */
1976         public function getUserPermissionsErrors(
1977                 $action, $user, $rigor = 'secure', $ignoreErrors = []
1978         ) {
1979                 $errors = $this->getUserPermissionsErrorsInternal( $action, $user, $rigor );
1980
1981                 // Remove the errors being ignored.
1982                 foreach ( $errors as $index => $error ) {
1983                         $errKey = is_array( $error ) ? $error[0] : $error;
1984
1985                         if ( in_array( $errKey, $ignoreErrors ) ) {
1986                                 unset( $errors[$index] );
1987                         }
1988                         if ( $errKey instanceof MessageSpecifier && in_array( $errKey->getKey(), $ignoreErrors ) ) {
1989                                 unset( $errors[$index] );
1990                         }
1991                 }
1992
1993                 return $errors;
1994         }
1995
1996         /**
1997          * Permissions checks that fail most often, and which are easiest to test.
1998          *
1999          * @param string $action The action to check
2000          * @param User $user User to check
2001          * @param array $errors List of current errors
2002          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2003          * @param bool $short Short circuit on first error
2004          *
2005          * @return array List of errors
2006          */
2007         private function checkQuickPermissions( $action, $user, $errors, $rigor, $short ) {
2008                 if ( !Hooks::run( 'TitleQuickPermissions',
2009                         [ $this, $user, $action, &$errors, ( $rigor !== 'quick' ), $short ] )
2010                 ) {
2011                         return $errors;
2012                 }
2013
2014                 if ( $action == 'create' ) {
2015                         if (
2016                                 ( $this->isTalkPage() && !$user->isAllowed( 'createtalk' ) ) ||
2017                                 ( !$this->isTalkPage() && !$user->isAllowed( 'createpage' ) )
2018                         ) {
2019                                 $errors[] = $user->isAnon() ? [ 'nocreatetext' ] : [ 'nocreate-loggedin' ];
2020                         }
2021                 } elseif ( $action == 'move' ) {
2022                         if ( !$user->isAllowed( 'move-rootuserpages' )
2023                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
2024                                 // Show user page-specific message only if the user can move other pages
2025                                 $errors[] = [ 'cant-move-user-page' ];
2026                         }
2027
2028                         // Check if user is allowed to move files if it's a file
2029                         if ( $this->mNamespace == NS_FILE && !$user->isAllowed( 'movefile' ) ) {
2030                                 $errors[] = [ 'movenotallowedfile' ];
2031                         }
2032
2033                         // Check if user is allowed to move category pages if it's a category page
2034                         if ( $this->mNamespace == NS_CATEGORY && !$user->isAllowed( 'move-categorypages' ) ) {
2035                                 $errors[] = [ 'cant-move-category-page' ];
2036                         }
2037
2038                         if ( !$user->isAllowed( 'move' ) ) {
2039                                 // User can't move anything
2040                                 $userCanMove = User::groupHasPermission( 'user', 'move' );
2041                                 $autoconfirmedCanMove = User::groupHasPermission( 'autoconfirmed', 'move' );
2042                                 if ( $user->isAnon() && ( $userCanMove || $autoconfirmedCanMove ) ) {
2043                                         // custom message if logged-in users without any special rights can move
2044                                         $errors[] = [ 'movenologintext' ];
2045                                 } else {
2046                                         $errors[] = [ 'movenotallowed' ];
2047                                 }
2048                         }
2049                 } elseif ( $action == 'move-target' ) {
2050                         if ( !$user->isAllowed( 'move' ) ) {
2051                                 // User can't move anything
2052                                 $errors[] = [ 'movenotallowed' ];
2053                         } elseif ( !$user->isAllowed( 'move-rootuserpages' )
2054                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
2055                                 // Show user page-specific message only if the user can move other pages
2056                                 $errors[] = [ 'cant-move-to-user-page' ];
2057                         } elseif ( !$user->isAllowed( 'move-categorypages' )
2058                                         && $this->mNamespace == NS_CATEGORY ) {
2059                                 // Show category page-specific message only if the user can move other pages
2060                                 $errors[] = [ 'cant-move-to-category-page' ];
2061                         }
2062                 } elseif ( !$user->isAllowed( $action ) ) {
2063                         $errors[] = $this->missingPermissionError( $action, $short );
2064                 }
2065
2066                 return $errors;
2067         }
2068
2069         /**
2070          * Add the resulting error code to the errors array
2071          *
2072          * @param array $errors List of current errors
2073          * @param array $result Result of errors
2074          *
2075          * @return array List of errors
2076          */
2077         private function resultToError( $errors, $result ) {
2078                 if ( is_array( $result ) && count( $result ) && !is_array( $result[0] ) ) {
2079                         // A single array representing an error
2080                         $errors[] = $result;
2081                 } elseif ( is_array( $result ) && is_array( $result[0] ) ) {
2082                         // A nested array representing multiple errors
2083                         $errors = array_merge( $errors, $result );
2084                 } elseif ( $result !== '' && is_string( $result ) ) {
2085                         // A string representing a message-id
2086                         $errors[] = [ $result ];
2087                 } elseif ( $result instanceof MessageSpecifier ) {
2088                         // A message specifier representing an error
2089                         $errors[] = [ $result ];
2090                 } elseif ( $result === false ) {
2091                         // a generic "We don't want them to do that"
2092                         $errors[] = [ 'badaccess-group0' ];
2093                 }
2094                 return $errors;
2095         }
2096
2097         /**
2098          * Check various permission hooks
2099          *
2100          * @param string $action The action to check
2101          * @param User $user User to check
2102          * @param array $errors List of current errors
2103          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2104          * @param bool $short Short circuit on first error
2105          *
2106          * @return array List of errors
2107          */
2108         private function checkPermissionHooks( $action, $user, $errors, $rigor, $short ) {
2109                 // Use getUserPermissionsErrors instead
2110                 $result = '';
2111                 // Avoid PHP 7.1 warning from passing $this by reference
2112                 $titleRef = $this;
2113                 if ( !Hooks::run( 'userCan', [ &$titleRef, &$user, $action, &$result ] ) ) {
2114                         return $result ? [] : [ [ 'badaccess-group0' ] ];
2115                 }
2116                 // Check getUserPermissionsErrors hook
2117                 // Avoid PHP 7.1 warning from passing $this by reference
2118                 $titleRef = $this;
2119                 if ( !Hooks::run( 'getUserPermissionsErrors', [ &$titleRef, &$user, $action, &$result ] ) ) {
2120                         $errors = $this->resultToError( $errors, $result );
2121                 }
2122                 // Check getUserPermissionsErrorsExpensive hook
2123                 if (
2124                         $rigor !== 'quick'
2125                         && !( $short && count( $errors ) > 0 )
2126                         && !Hooks::run( 'getUserPermissionsErrorsExpensive', [ &$titleRef, &$user, $action, &$result ] )
2127                 ) {
2128                         $errors = $this->resultToError( $errors, $result );
2129                 }
2130
2131                 return $errors;
2132         }
2133
2134         /**
2135          * Check permissions on special pages & namespaces
2136          *
2137          * @param string $action The action to check
2138          * @param User $user User to check
2139          * @param array $errors List of current errors
2140          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2141          * @param bool $short Short circuit on first error
2142          *
2143          * @return array List of errors
2144          */
2145         private function checkSpecialsAndNSPermissions( $action, $user, $errors, $rigor, $short ) {
2146                 # Only 'createaccount' can be performed on special pages,
2147                 # which don't actually exist in the DB.
2148                 if ( $this->isSpecialPage() && $action !== 'createaccount' ) {
2149                         $errors[] = [ 'ns-specialprotected' ];
2150                 }
2151
2152                 # Check $wgNamespaceProtection for restricted namespaces
2153                 if ( $this->isNamespaceProtected( $user ) ) {
2154                         $ns = $this->mNamespace == NS_MAIN ?
2155                                 wfMessage( 'nstab-main' )->text() : $this->getNsText();
2156                         $errors[] = $this->mNamespace == NS_MEDIAWIKI ?
2157                                 [ 'protectedinterface', $action ] : [ 'namespaceprotected', $ns, $action ];
2158                 }
2159
2160                 return $errors;
2161         }
2162
2163         /**
2164          * Check CSS/JS sub-page permissions
2165          *
2166          * @param string $action The action to check
2167          * @param User $user User to check
2168          * @param array $errors List of current errors
2169          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2170          * @param bool $short Short circuit on first error
2171          *
2172          * @return array List of errors
2173          */
2174         private function checkCSSandJSPermissions( $action, $user, $errors, $rigor, $short ) {
2175                 # Protect css/js subpages of user pages
2176                 # XXX: this might be better using restrictions
2177                 if ( $action != 'patrol' ) {
2178                         if ( preg_match( '/^' . preg_quote( $user->getName(), '/' ) . '\//', $this->mTextform ) ) {
2179                                 if ( $this->isCssSubpage() && !$user->isAllowedAny( 'editmyusercss', 'editusercss' ) ) {
2180                                         $errors[] = [ 'mycustomcssprotected', $action ];
2181                                 } elseif ( $this->isJsSubpage() && !$user->isAllowedAny( 'editmyuserjs', 'edituserjs' ) ) {
2182                                         $errors[] = [ 'mycustomjsprotected', $action ];
2183                                 }
2184                         } else {
2185                                 if ( $this->isCssSubpage() && !$user->isAllowed( 'editusercss' ) ) {
2186                                         $errors[] = [ 'customcssprotected', $action ];
2187                                 } elseif ( $this->isJsSubpage() && !$user->isAllowed( 'edituserjs' ) ) {
2188                                         $errors[] = [ 'customjsprotected', $action ];
2189                                 }
2190                         }
2191                 }
2192
2193                 return $errors;
2194         }
2195
2196         /**
2197          * Check against page_restrictions table requirements on this
2198          * page. The user must possess all required rights for this
2199          * action.
2200          *
2201          * @param string $action The action to check
2202          * @param User $user User to check
2203          * @param array $errors List of current errors
2204          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2205          * @param bool $short Short circuit on first error
2206          *
2207          * @return array List of errors
2208          */
2209         private function checkPageRestrictions( $action, $user, $errors, $rigor, $short ) {
2210                 foreach ( $this->getRestrictions( $action ) as $right ) {
2211                         // Backwards compatibility, rewrite sysop -> editprotected
2212                         if ( $right == 'sysop' ) {
2213                                 $right = 'editprotected';
2214                         }
2215                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2216                         if ( $right == 'autoconfirmed' ) {
2217                                 $right = 'editsemiprotected';
2218                         }
2219                         if ( $right == '' ) {
2220                                 continue;
2221                         }
2222                         if ( !$user->isAllowed( $right ) ) {
2223                                 $errors[] = [ 'protectedpagetext', $right, $action ];
2224                         } elseif ( $this->mCascadeRestriction && !$user->isAllowed( 'protect' ) ) {
2225                                 $errors[] = [ 'protectedpagetext', 'protect', $action ];
2226                         }
2227                 }
2228
2229                 return $errors;
2230         }
2231
2232         /**
2233          * Check restrictions on cascading pages.
2234          *
2235          * @param string $action The action to check
2236          * @param User $user User to check
2237          * @param array $errors List of current errors
2238          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2239          * @param bool $short Short circuit on first error
2240          *
2241          * @return array List of errors
2242          */
2243         private function checkCascadingSourcesRestrictions( $action, $user, $errors, $rigor, $short ) {
2244                 if ( $rigor !== 'quick' && !$this->isCssJsSubpage() ) {
2245                         # We /could/ use the protection level on the source page, but it's
2246                         # fairly ugly as we have to establish a precedence hierarchy for pages
2247                         # included by multiple cascade-protected pages. So just restrict
2248                         # it to people with 'protect' permission, as they could remove the
2249                         # protection anyway.
2250                         list( $cascadingSources, $restrictions ) = $this->getCascadeProtectionSources();
2251                         # Cascading protection depends on more than this page...
2252                         # Several cascading protected pages may include this page...
2253                         # Check each cascading level
2254                         # This is only for protection restrictions, not for all actions
2255                         if ( isset( $restrictions[$action] ) ) {
2256                                 foreach ( $restrictions[$action] as $right ) {
2257                                         // Backwards compatibility, rewrite sysop -> editprotected
2258                                         if ( $right == 'sysop' ) {
2259                                                 $right = 'editprotected';
2260                                         }
2261                                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2262                                         if ( $right == 'autoconfirmed' ) {
2263                                                 $right = 'editsemiprotected';
2264                                         }
2265                                         if ( $right != '' && !$user->isAllowedAll( 'protect', $right ) ) {
2266                                                 $pages = '';
2267                                                 foreach ( $cascadingSources as $page ) {
2268                                                         $pages .= '* [[:' . $page->getPrefixedText() . "]]\n";
2269                                                 }
2270                                                 $errors[] = [ 'cascadeprotected', count( $cascadingSources ), $pages, $action ];
2271                                         }
2272                                 }
2273                         }
2274                 }
2275
2276                 return $errors;
2277         }
2278
2279         /**
2280          * Check action permissions not already checked in checkQuickPermissions
2281          *
2282          * @param string $action The action to check
2283          * @param User $user User to check
2284          * @param array $errors List of current errors
2285          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2286          * @param bool $short Short circuit on first error
2287          *
2288          * @return array List of errors
2289          */
2290         private function checkActionPermissions( $action, $user, $errors, $rigor, $short ) {
2291                 global $wgDeleteRevisionsLimit, $wgLang;
2292
2293                 if ( $action == 'protect' ) {
2294                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit', $user, $rigor, true ) ) ) {
2295                                 // If they can't edit, they shouldn't protect.
2296                                 $errors[] = [ 'protect-cantedit' ];
2297                         }
2298                 } elseif ( $action == 'create' ) {
2299                         $title_protection = $this->getTitleProtection();
2300                         if ( $title_protection ) {
2301                                 if ( $title_protection['permission'] == ''
2302                                         || !$user->isAllowed( $title_protection['permission'] )
2303                                 ) {
2304                                         $errors[] = [
2305                                                 'titleprotected',
2306                                                 User::whoIs( $title_protection['user'] ),
2307                                                 $title_protection['reason']
2308                                         ];
2309                                 }
2310                         }
2311                 } elseif ( $action == 'move' ) {
2312                         // Check for immobile pages
2313                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2314                                 // Specific message for this case
2315                                 $errors[] = [ 'immobile-source-namespace', $this->getNsText() ];
2316                         } elseif ( !$this->isMovable() ) {
2317                                 // Less specific message for rarer cases
2318                                 $errors[] = [ 'immobile-source-page' ];
2319                         }
2320                 } elseif ( $action == 'move-target' ) {
2321                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2322                                 $errors[] = [ 'immobile-target-namespace', $this->getNsText() ];
2323                         } elseif ( !$this->isMovable() ) {
2324                                 $errors[] = [ 'immobile-target-page' ];
2325                         }
2326                 } elseif ( $action == 'delete' ) {
2327                         $tempErrors = $this->checkPageRestrictions( 'edit', $user, [], $rigor, true );
2328                         if ( !$tempErrors ) {
2329                                 $tempErrors = $this->checkCascadingSourcesRestrictions( 'edit',
2330                                         $user, $tempErrors, $rigor, true );
2331                         }
2332                         if ( $tempErrors ) {
2333                                 // If protection keeps them from editing, they shouldn't be able to delete.
2334                                 $errors[] = [ 'deleteprotected' ];
2335                         }
2336                         if ( $rigor !== 'quick' && $wgDeleteRevisionsLimit
2337                                 && !$this->userCan( 'bigdelete', $user ) && $this->isBigDeletion()
2338                         ) {
2339                                 $errors[] = [ 'delete-toobig', $wgLang->formatNum( $wgDeleteRevisionsLimit ) ];
2340                         }
2341                 } elseif ( $action === 'undelete' ) {
2342                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit', $user, $rigor, true ) ) ) {
2343                                 // Undeleting implies editing
2344                                 $errors[] = [ 'undelete-cantedit' ];
2345                         }
2346                         if ( !$this->exists()
2347                                 && count( $this->getUserPermissionsErrorsInternal( 'create', $user, $rigor, true ) )
2348                         ) {
2349                                 // Undeleting where nothing currently exists implies creating
2350                                 $errors[] = [ 'undelete-cantcreate' ];
2351                         }
2352                 }
2353                 return $errors;
2354         }
2355
2356         /**
2357          * Check that the user isn't blocked from editing.
2358          *
2359          * @param string $action The action to check
2360          * @param User $user User to check
2361          * @param array $errors List of current errors
2362          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2363          * @param bool $short Short circuit on first error
2364          *
2365          * @return array List of errors
2366          */
2367         private function checkUserBlock( $action, $user, $errors, $rigor, $short ) {
2368                 global $wgEmailConfirmToEdit, $wgBlockDisablesLogin;
2369                 // Account creation blocks handled at userlogin.
2370                 // Unblocking handled in SpecialUnblock
2371                 if ( $rigor === 'quick' || in_array( $action, [ 'createaccount', 'unblock' ] ) ) {
2372                         return $errors;
2373                 }
2374
2375                 // Optimize for a very common case
2376                 if ( $action === 'read' && !$wgBlockDisablesLogin ) {
2377                         return $errors;
2378                 }
2379
2380                 if ( $wgEmailConfirmToEdit && !$user->isEmailConfirmed() ) {
2381                         $errors[] = [ 'confirmedittext' ];
2382                 }
2383
2384                 $useSlave = ( $rigor !== 'secure' );
2385                 if ( ( $action == 'edit' || $action == 'create' )
2386                         && !$user->isBlockedFrom( $this, $useSlave )
2387                 ) {
2388                         // Don't block the user from editing their own talk page unless they've been
2389                         // explicitly blocked from that too.
2390                 } elseif ( $user->isBlocked() && $user->getBlock()->prevents( $action ) !== false ) {
2391                         // @todo FIXME: Pass the relevant context into this function.
2392                         $errors[] = $user->getBlock()->getPermissionsError( RequestContext::getMain() );
2393                 }
2394
2395                 return $errors;
2396         }
2397
2398         /**
2399          * Check that the user is allowed to read this page.
2400          *
2401          * @param string $action The action to check
2402          * @param User $user User to check
2403          * @param array $errors List of current errors
2404          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2405          * @param bool $short Short circuit on first error
2406          *
2407          * @return array List of errors
2408          */
2409         private function checkReadPermissions( $action, $user, $errors, $rigor, $short ) {
2410                 global $wgWhitelistRead, $wgWhitelistReadRegexp;
2411
2412                 $whitelisted = false;
2413                 if ( User::isEveryoneAllowed( 'read' ) ) {
2414                         # Shortcut for public wikis, allows skipping quite a bit of code
2415                         $whitelisted = true;
2416                 } elseif ( $user->isAllowed( 'read' ) ) {
2417                         # If the user is allowed to read pages, he is allowed to read all pages
2418                         $whitelisted = true;
2419                 } elseif ( $this->isSpecial( 'Userlogin' )
2420                         || $this->isSpecial( 'PasswordReset' )
2421                         || $this->isSpecial( 'Userlogout' )
2422                 ) {
2423                         # Always grant access to the login page.
2424                         # Even anons need to be able to log in.
2425                         $whitelisted = true;
2426                 } elseif ( is_array( $wgWhitelistRead ) && count( $wgWhitelistRead ) ) {
2427                         # Time to check the whitelist
2428                         # Only do these checks is there's something to check against
2429                         $name = $this->getPrefixedText();
2430                         $dbName = $this->getPrefixedDBkey();
2431
2432                         // Check for explicit whitelisting with and without underscores
2433                         if ( in_array( $name, $wgWhitelistRead, true ) || in_array( $dbName, $wgWhitelistRead, true ) ) {
2434                                 $whitelisted = true;
2435                         } elseif ( $this->getNamespace() == NS_MAIN ) {
2436                                 # Old settings might have the title prefixed with
2437                                 # a colon for main-namespace pages
2438                                 if ( in_array( ':' . $name, $wgWhitelistRead ) ) {
2439                                         $whitelisted = true;
2440                                 }
2441                         } elseif ( $this->isSpecialPage() ) {
2442                                 # If it's a special page, ditch the subpage bit and check again
2443                                 $name = $this->getDBkey();
2444                                 list( $name, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $name );
2445                                 if ( $name ) {
2446                                         $pure = SpecialPage::getTitleFor( $name )->getPrefixedText();
2447                                         if ( in_array( $pure, $wgWhitelistRead, true ) ) {
2448                                                 $whitelisted = true;
2449                                         }
2450                                 }
2451                         }
2452                 }
2453
2454                 if ( !$whitelisted && is_array( $wgWhitelistReadRegexp ) && !empty( $wgWhitelistReadRegexp ) ) {
2455                         $name = $this->getPrefixedText();
2456                         // Check for regex whitelisting
2457                         foreach ( $wgWhitelistReadRegexp as $listItem ) {
2458                                 if ( preg_match( $listItem, $name ) ) {
2459                                         $whitelisted = true;
2460                                         break;
2461                                 }
2462                         }
2463                 }
2464
2465                 if ( !$whitelisted ) {
2466                         # If the title is not whitelisted, give extensions a chance to do so...
2467                         Hooks::run( 'TitleReadWhitelist', [ $this, $user, &$whitelisted ] );
2468                         if ( !$whitelisted ) {
2469                                 $errors[] = $this->missingPermissionError( $action, $short );
2470                         }
2471                 }
2472
2473                 return $errors;
2474         }
2475
2476         /**
2477          * Get a description array when the user doesn't have the right to perform
2478          * $action (i.e. when User::isAllowed() returns false)
2479          *
2480          * @param string $action The action to check
2481          * @param bool $short Short circuit on first error
2482          * @return array Array containing an error message key and any parameters
2483          */
2484         private function missingPermissionError( $action, $short ) {
2485                 // We avoid expensive display logic for quickUserCan's and such
2486                 if ( $short ) {
2487                         return [ 'badaccess-group0' ];
2488                 }
2489
2490                 return User::newFatalPermissionDeniedStatus( $action )->getErrorsArray()[0];
2491         }
2492
2493         /**
2494          * Can $user perform $action on this page? This is an internal function,
2495          * with multiple levels of checks depending on performance needs; see $rigor below.
2496          * It does not check wfReadOnly().
2497          *
2498          * @param string $action Action that permission needs to be checked for
2499          * @param User $user User to check
2500          * @param string $rigor One of (quick,full,secure)
2501          *   - quick  : does cheap permission checks from replica DBs (usable for GUI creation)
2502          *   - full   : does cheap and expensive checks possibly from a replica DB
2503          *   - secure : does cheap and expensive checks, using the master as needed
2504          * @param bool $short Set this to true to stop after the first permission error.
2505          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
2506          */
2507         protected function getUserPermissionsErrorsInternal(
2508                 $action, $user, $rigor = 'secure', $short = false
2509         ) {
2510                 if ( $rigor === true ) {
2511                         $rigor = 'secure'; // b/c
2512                 } elseif ( $rigor === false ) {
2513                         $rigor = 'quick'; // b/c
2514                 } elseif ( !in_array( $rigor, [ 'quick', 'full', 'secure' ] ) ) {
2515                         throw new Exception( "Invalid rigor parameter '$rigor'." );
2516                 }
2517
2518                 # Read has special handling
2519                 if ( $action == 'read' ) {
2520                         $checks = [
2521                                 'checkPermissionHooks',
2522                                 'checkReadPermissions',
2523                                 'checkUserBlock', // for wgBlockDisablesLogin
2524                         ];
2525                 # Don't call checkSpecialsAndNSPermissions or checkCSSandJSPermissions
2526                 # here as it will lead to duplicate error messages. This is okay to do
2527                 # since anywhere that checks for create will also check for edit, and
2528                 # those checks are called for edit.
2529                 } elseif ( $action == 'create' ) {
2530                         $checks = [
2531                                 'checkQuickPermissions',
2532                                 'checkPermissionHooks',
2533                                 'checkPageRestrictions',
2534                                 'checkCascadingSourcesRestrictions',
2535                                 'checkActionPermissions',
2536                                 'checkUserBlock'
2537                         ];
2538                 } else {
2539                         $checks = [
2540                                 'checkQuickPermissions',
2541                                 'checkPermissionHooks',
2542                                 'checkSpecialsAndNSPermissions',
2543                                 'checkCSSandJSPermissions',
2544                                 'checkPageRestrictions',
2545                                 'checkCascadingSourcesRestrictions',
2546                                 'checkActionPermissions',
2547                                 'checkUserBlock'
2548                         ];
2549                 }
2550
2551                 $errors = [];
2552                 while ( count( $checks ) > 0 &&
2553                                 !( $short && count( $errors ) > 0 ) ) {
2554                         $method = array_shift( $checks );
2555                         $errors = $this->$method( $action, $user, $errors, $rigor, $short );
2556                 }
2557
2558                 return $errors;
2559         }
2560
2561         /**
2562          * Get a filtered list of all restriction types supported by this wiki.
2563          * @param bool $exists True to get all restriction types that apply to
2564          * titles that do exist, False for all restriction types that apply to
2565          * titles that do not exist
2566          * @return array
2567          */
2568         public static function getFilteredRestrictionTypes( $exists = true ) {
2569                 global $wgRestrictionTypes;
2570                 $types = $wgRestrictionTypes;
2571                 if ( $exists ) {
2572                         # Remove the create restriction for existing titles
2573                         $types = array_diff( $types, [ 'create' ] );
2574                 } else {
2575                         # Only the create and upload restrictions apply to non-existing titles
2576                         $types = array_intersect( $types, [ 'create', 'upload' ] );
2577                 }
2578                 return $types;
2579         }
2580
2581         /**
2582          * Returns restriction types for the current Title
2583          *
2584          * @return array Applicable restriction types
2585          */
2586         public function getRestrictionTypes() {
2587                 if ( $this->isSpecialPage() ) {
2588                         return [];
2589                 }
2590
2591                 $types = self::getFilteredRestrictionTypes( $this->exists() );
2592
2593                 if ( $this->getNamespace() != NS_FILE ) {
2594                         # Remove the upload restriction for non-file titles
2595                         $types = array_diff( $types, [ 'upload' ] );
2596                 }
2597
2598                 Hooks::run( 'TitleGetRestrictionTypes', [ $this, &$types ] );
2599
2600                 wfDebug( __METHOD__ . ': applicable restrictions to [[' .
2601                         $this->getPrefixedText() . ']] are {' . implode( ',', $types ) . "}\n" );
2602
2603                 return $types;
2604         }
2605
2606         /**
2607          * Is this title subject to title protection?
2608          * Title protection is the one applied against creation of such title.
2609          *
2610          * @return array|bool An associative array representing any existent title
2611          *   protection, or false if there's none.
2612          */
2613         public function getTitleProtection() {
2614                 $protection = $this->getTitleProtectionInternal();
2615                 if ( $protection ) {
2616                         if ( $protection['permission'] == 'sysop' ) {
2617                                 $protection['permission'] = 'editprotected'; // B/C
2618                         }
2619                         if ( $protection['permission'] == 'autoconfirmed' ) {
2620                                 $protection['permission'] = 'editsemiprotected'; // B/C
2621                         }
2622                 }
2623                 return $protection;
2624         }
2625
2626         /**
2627          * Fetch title protection settings
2628          *
2629          * To work correctly, $this->loadRestrictions() needs to have access to the
2630          * actual protections in the database without munging 'sysop' =>
2631          * 'editprotected' and 'autoconfirmed' => 'editsemiprotected'. Other
2632          * callers probably want $this->getTitleProtection() instead.
2633          *
2634          * @return array|bool
2635          */
2636         protected function getTitleProtectionInternal() {
2637                 // Can't protect pages in special namespaces
2638                 if ( $this->getNamespace() < 0 ) {
2639                         return false;
2640                 }
2641
2642                 // Can't protect pages that exist.
2643                 if ( $this->exists() ) {
2644                         return false;
2645                 }
2646
2647                 if ( $this->mTitleProtection === null ) {
2648                         $dbr = wfGetDB( DB_REPLICA );
2649                         $res = $dbr->select(
2650                                 'protected_titles',
2651                                 [
2652                                         'user' => 'pt_user',
2653                                         'reason' => 'pt_reason',
2654                                         'expiry' => 'pt_expiry',
2655                                         'permission' => 'pt_create_perm'
2656                                 ],
2657                                 [ 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ],
2658                                 __METHOD__
2659                         );
2660
2661                         // fetchRow returns false if there are no rows.
2662                         $row = $dbr->fetchRow( $res );
2663                         if ( $row ) {
2664                                 $row['expiry'] = $dbr->decodeExpiry( $row['expiry'] );
2665                         }
2666                         $this->mTitleProtection = $row;
2667                 }
2668                 return $this->mTitleProtection;
2669         }
2670
2671         /**
2672          * Remove any title protection due to page existing
2673          */
2674         public function deleteTitleProtection() {
2675                 $dbw = wfGetDB( DB_MASTER );
2676
2677                 $dbw->delete(
2678                         'protected_titles',
2679                         [ 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ],
2680                         __METHOD__
2681                 );
2682                 $this->mTitleProtection = false;
2683         }
2684
2685         /**
2686          * Is this page "semi-protected" - the *only* protection levels are listed
2687          * in $wgSemiprotectedRestrictionLevels?
2688          *
2689          * @param string $action Action to check (default: edit)
2690          * @return bool
2691          */
2692         public function isSemiProtected( $action = 'edit' ) {
2693                 global $wgSemiprotectedRestrictionLevels;
2694
2695                 $restrictions = $this->getRestrictions( $action );
2696                 $semi = $wgSemiprotectedRestrictionLevels;
2697                 if ( !$restrictions || !$semi ) {
2698                         // Not protected, or all protection is full protection
2699                         return false;
2700                 }
2701
2702                 // Remap autoconfirmed to editsemiprotected for BC
2703                 foreach ( array_keys( $semi, 'autoconfirmed' ) as $key ) {
2704                         $semi[$key] = 'editsemiprotected';
2705                 }
2706                 foreach ( array_keys( $restrictions, 'autoconfirmed' ) as $key ) {
2707                         $restrictions[$key] = 'editsemiprotected';
2708                 }
2709
2710                 return !array_diff( $restrictions, $semi );
2711         }
2712
2713         /**
2714          * Does the title correspond to a protected article?
2715          *
2716          * @param string $action The action the page is protected from,
2717          * by default checks all actions.
2718          * @return bool
2719          */
2720         public function isProtected( $action = '' ) {
2721                 global $wgRestrictionLevels;
2722
2723                 $restrictionTypes = $this->getRestrictionTypes();
2724
2725                 # Special pages have inherent protection
2726                 if ( $this->isSpecialPage() ) {
2727                         return true;
2728                 }
2729
2730                 # Check regular protection levels
2731                 foreach ( $restrictionTypes as $type ) {
2732                         if ( $action == $type || $action == '' ) {
2733                                 $r = $this->getRestrictions( $type );
2734                                 foreach ( $wgRestrictionLevels as $level ) {
2735                                         if ( in_array( $level, $r ) && $level != '' ) {
2736                                                 return true;
2737                                         }
2738                                 }
2739                         }
2740                 }
2741
2742                 return false;
2743         }
2744
2745         /**
2746          * Determines if $user is unable to edit this page because it has been protected
2747          * by $wgNamespaceProtection.
2748          *
2749          * @param User $user User object to check permissions
2750          * @return bool
2751          */
2752         public function isNamespaceProtected( User $user ) {
2753                 global $wgNamespaceProtection;
2754
2755                 if ( isset( $wgNamespaceProtection[$this->mNamespace] ) ) {
2756                         foreach ( (array)$wgNamespaceProtection[$this->mNamespace] as $right ) {
2757                                 if ( $right != '' && !$user->isAllowed( $right ) ) {
2758                                         return true;
2759                                 }
2760                         }
2761                 }
2762                 return false;
2763         }
2764
2765         /**
2766          * Cascading protection: Return true if cascading restrictions apply to this page, false if not.
2767          *
2768          * @return bool If the page is subject to cascading restrictions.
2769          */
2770         public function isCascadeProtected() {
2771                 list( $sources, /* $restrictions */ ) = $this->getCascadeProtectionSources( false );
2772                 return ( $sources > 0 );
2773         }
2774
2775         /**
2776          * Determines whether cascading protection sources have already been loaded from
2777          * the database.
2778          *
2779          * @param bool $getPages True to check if the pages are loaded, or false to check
2780          * if the status is loaded.
2781          * @return bool Whether or not the specified information has been loaded
2782          * @since 1.23
2783          */
2784         public function areCascadeProtectionSourcesLoaded( $getPages = true ) {
2785                 return $getPages ? $this->mCascadeSources !== null : $this->mHasCascadingRestrictions !== null;
2786         }
2787
2788         /**
2789          * Cascading protection: Get the source of any cascading restrictions on this page.
2790          *
2791          * @param bool $getPages Whether or not to retrieve the actual pages
2792          *        that the restrictions have come from and the actual restrictions
2793          *        themselves.
2794          * @return array Two elements: First is an array of Title objects of the
2795          *        pages from which cascading restrictions have come, false for
2796          *        none, or true if such restrictions exist but $getPages was not
2797          *        set. Second is an array like that returned by
2798          *        Title::getAllRestrictions(), or an empty array if $getPages is
2799          *        false.
2800          */
2801         public function getCascadeProtectionSources( $getPages = true ) {
2802                 $pagerestrictions = [];
2803
2804                 if ( $this->mCascadeSources !== null && $getPages ) {
2805                         return [ $this->mCascadeSources, $this->mCascadingRestrictions ];
2806                 } elseif ( $this->mHasCascadingRestrictions !== null && !$getPages ) {
2807                         return [ $this->mHasCascadingRestrictions, $pagerestrictions ];
2808                 }
2809
2810                 $dbr = wfGetDB( DB_REPLICA );
2811
2812                 if ( $this->getNamespace() == NS_FILE ) {
2813                         $tables = [ 'imagelinks', 'page_restrictions' ];
2814                         $where_clauses = [
2815                                 'il_to' => $this->getDBkey(),
2816                                 'il_from=pr_page',
2817                                 'pr_cascade' => 1
2818                         ];
2819                 } else {
2820                         $tables = [ 'templatelinks', 'page_restrictions' ];
2821                         $where_clauses = [
2822                                 'tl_namespace' => $this->getNamespace(),
2823                                 'tl_title' => $this->getDBkey(),
2824                                 'tl_from=pr_page',
2825                                 'pr_cascade' => 1
2826                         ];
2827                 }
2828
2829                 if ( $getPages ) {
2830                         $cols = [ 'pr_page', 'page_namespace', 'page_title',
2831                                 'pr_expiry', 'pr_type', 'pr_level' ];
2832                         $where_clauses[] = 'page_id=pr_page';
2833                         $tables[] = 'page';
2834                 } else {
2835                         $cols = [ 'pr_expiry' ];
2836                 }
2837
2838                 $res = $dbr->select( $tables, $cols, $where_clauses, __METHOD__ );
2839
2840                 $sources = $getPages ? [] : false;
2841                 $now = wfTimestampNow();
2842
2843                 foreach ( $res as $row ) {
2844                         $expiry = $dbr->decodeExpiry( $row->pr_expiry );
2845                         if ( $expiry > $now ) {
2846                                 if ( $getPages ) {
2847                                         $page_id = $row->pr_page;
2848                                         $page_ns = $row->page_namespace;
2849                                         $page_title = $row->page_title;
2850                                         $sources[$page_id] = Title::makeTitle( $page_ns, $page_title );
2851                                         # Add groups needed for each restriction type if its not already there
2852                                         # Make sure this restriction type still exists
2853
2854                                         if ( !isset( $pagerestrictions[$row->pr_type] ) ) {
2855                                                 $pagerestrictions[$row->pr_type] = [];
2856                                         }
2857
2858                                         if (
2859                                                 isset( $pagerestrictions[$row->pr_type] )
2860                                                 && !in_array( $row->pr_level, $pagerestrictions[$row->pr_type] )
2861                                         ) {
2862                                                 $pagerestrictions[$row->pr_type][] = $row->pr_level;
2863                                         }
2864                                 } else {
2865                                         $sources = true;
2866                                 }
2867                         }
2868                 }
2869
2870                 if ( $getPages ) {
2871                         $this->mCascadeSources = $sources;
2872                         $this->mCascadingRestrictions = $pagerestrictions;
2873                 } else {
2874                         $this->mHasCascadingRestrictions = $sources;
2875                 }
2876
2877                 return [ $sources, $pagerestrictions ];
2878         }
2879
2880         /**
2881          * Accessor for mRestrictionsLoaded
2882          *
2883          * @return bool Whether or not the page's restrictions have already been
2884          * loaded from the database
2885          * @since 1.23
2886          */
2887         public function areRestrictionsLoaded() {
2888                 return $this->mRestrictionsLoaded;
2889         }
2890
2891         /**
2892          * Accessor/initialisation for mRestrictions
2893          *
2894          * @param string $action Action that permission needs to be checked for
2895          * @return array Restriction levels needed to take the action. All levels are
2896          *     required. Note that restriction levels are normally user rights, but 'sysop'
2897          *     and 'autoconfirmed' are also allowed for backwards compatibility. These should
2898          *     be mapped to 'editprotected' and 'editsemiprotected' respectively.
2899          */
2900         public function getRestrictions( $action ) {
2901                 if ( !$this->mRestrictionsLoaded ) {
2902                         $this->loadRestrictions();
2903                 }
2904                 return isset( $this->mRestrictions[$action] )
2905                                 ? $this->mRestrictions[$action]
2906                                 : [];
2907         }
2908
2909         /**
2910          * Accessor/initialisation for mRestrictions
2911          *
2912          * @return array Keys are actions, values are arrays as returned by
2913          *     Title::getRestrictions()
2914          * @since 1.23
2915          */
2916         public function getAllRestrictions() {
2917                 if ( !$this->mRestrictionsLoaded ) {
2918                         $this->loadRestrictions();
2919                 }
2920                 return $this->mRestrictions;
2921         }
2922
2923         /**
2924          * Get the expiry time for the restriction against a given action
2925          *
2926          * @param string $action
2927          * @return string|bool 14-char timestamp, or 'infinity' if the page is protected forever
2928          *     or not protected at all, or false if the action is not recognised.
2929          */
2930         public function getRestrictionExpiry( $action ) {
2931                 if ( !$this->mRestrictionsLoaded ) {
2932                         $this->loadRestrictions();
2933                 }
2934                 return isset( $this->mRestrictionsExpiry[$action] ) ? $this->mRestrictionsExpiry[$action] : false;
2935         }
2936
2937         /**
2938          * Returns cascading restrictions for the current article
2939          *
2940          * @return bool
2941          */
2942         function areRestrictionsCascading() {
2943                 if ( !$this->mRestrictionsLoaded ) {
2944                         $this->loadRestrictions();
2945                 }
2946
2947                 return $this->mCascadeRestriction;
2948         }
2949
2950         /**
2951          * Compiles list of active page restrictions from both page table (pre 1.10)
2952          * and page_restrictions table for this existing page.
2953          * Public for usage by LiquidThreads.
2954          *
2955          * @param array $rows Array of db result objects
2956          * @param string $oldFashionedRestrictions Comma-separated list of page
2957          *   restrictions from page table (pre 1.10)
2958          */
2959         public function loadRestrictionsFromRows( $rows, $oldFashionedRestrictions = null ) {
2960                 $dbr = wfGetDB( DB_REPLICA );
2961
2962                 $restrictionTypes = $this->getRestrictionTypes();
2963
2964                 foreach ( $restrictionTypes as $type ) {
2965                         $this->mRestrictions[$type] = [];
2966                         $this->mRestrictionsExpiry[$type] = 'infinity';
2967                 }
2968
2969                 $this->mCascadeRestriction = false;
2970
2971                 # Backwards-compatibility: also load the restrictions from the page record (old format).
2972                 if ( $oldFashionedRestrictions !== null ) {
2973                         $this->mOldRestrictions = $oldFashionedRestrictions;
2974                 }
2975
2976                 if ( $this->mOldRestrictions === false ) {
2977                         $this->mOldRestrictions = $dbr->selectField( 'page', 'page_restrictions',
2978                                 [ 'page_id' => $this->getArticleID() ], __METHOD__ );
2979                 }
2980
2981                 if ( $this->mOldRestrictions != '' ) {
2982                         foreach ( explode( ':', trim( $this->mOldRestrictions ) ) as $restrict ) {
2983                                 $temp = explode( '=', trim( $restrict ) );
2984                                 if ( count( $temp ) == 1 ) {
2985                                         // old old format should be treated as edit/move restriction
2986                                         $this->mRestrictions['edit'] = explode( ',', trim( $temp[0] ) );
2987                                         $this->mRestrictions['move'] = explode( ',', trim( $temp[0] ) );
2988                                 } else {
2989                                         $restriction = trim( $temp[1] );
2990                                         if ( $restriction != '' ) { // some old entries are empty
2991                                                 $this->mRestrictions[$temp[0]] = explode( ',', $restriction );
2992                                         }
2993                                 }
2994                         }
2995                 }
2996
2997                 if ( count( $rows ) ) {
2998                         # Current system - load second to make them override.
2999                         $now = wfTimestampNow();
3000
3001                         # Cycle through all the restrictions.
3002                         foreach ( $rows as $row ) {
3003                                 // Don't take care of restrictions types that aren't allowed
3004                                 if ( !in_array( $row->pr_type, $restrictionTypes ) ) {
3005                                         continue;
3006                                 }
3007
3008                                 $expiry = $dbr->decodeExpiry( $row->pr_expiry );
3009
3010                                 // Only apply the restrictions if they haven't expired!
3011                                 if ( !$expiry || $expiry > $now ) {
3012                                         $this->mRestrictionsExpiry[$row->pr_type] = $expiry;
3013                                         $this->mRestrictions[$row->pr_type] = explode( ',', trim( $row->pr_level ) );
3014
3015                                         $this->mCascadeRestriction |= $row->pr_cascade;
3016                                 }
3017                         }
3018                 }
3019
3020                 $this->mRestrictionsLoaded = true;
3021         }
3022
3023         /**
3024          * Load restrictions from the page_restrictions table
3025          *
3026          * @param string $oldFashionedRestrictions Comma-separated list of page
3027          *   restrictions from page table (pre 1.10)
3028          */
3029         public function loadRestrictions( $oldFashionedRestrictions = null ) {
3030                 if ( $this->mRestrictionsLoaded ) {
3031                         return;
3032                 }
3033
3034                 $id = $this->getArticleID();
3035                 if ( $id ) {
3036                         $cache = ObjectCache::getMainWANInstance();
3037                         $rows = $cache->getWithSetCallback(
3038                                 // Page protections always leave a new null revision
3039                                 $cache->makeKey( 'page-restrictions', $id, $this->getLatestRevID() ),
3040                                 $cache::TTL_DAY,
3041                                 function ( $curValue, &$ttl, array &$setOpts ) {
3042                                         $dbr = wfGetDB( DB_REPLICA );
3043
3044                                         $setOpts += Database::getCacheSetOptions( $dbr );
3045
3046                                         return iterator_to_array(
3047                                                 $dbr->select(
3048                                                         'page_restrictions',
3049                                                         [ 'pr_type', 'pr_expiry', 'pr_level', 'pr_cascade' ],
3050                                                         [ 'pr_page' => $this->getArticleID() ],
3051                                                         __METHOD__
3052                                                 )
3053                                         );
3054                                 }
3055                         );
3056
3057                         $this->loadRestrictionsFromRows( $rows, $oldFashionedRestrictions );
3058                 } else {
3059                         $title_protection = $this->getTitleProtectionInternal();
3060
3061                         if ( $title_protection ) {
3062                                 $now = wfTimestampNow();
3063                                 $expiry = wfGetDB( DB_REPLICA )->decodeExpiry( $title_protection['expiry'] );
3064
3065                                 if ( !$expiry || $expiry > $now ) {
3066                                         // Apply the restrictions
3067                                         $this->mRestrictionsExpiry['create'] = $expiry;
3068                                         $this->mRestrictions['create'] =
3069                                                 explode( ',', trim( $title_protection['permission'] ) );
3070                                 } else { // Get rid of the old restrictions
3071                                         $this->mTitleProtection = false;
3072                                 }
3073                         } else {
3074                                 $this->mRestrictionsExpiry['create'] = 'infinity';
3075                         }
3076                         $this->mRestrictionsLoaded = true;
3077                 }
3078         }
3079
3080         /**
3081          * Flush the protection cache in this object and force reload from the database.
3082          * This is used when updating protection from WikiPage::doUpdateRestrictions().
3083          */
3084         public function flushRestrictions() {
3085                 $this->mRestrictionsLoaded = false;
3086                 $this->mTitleProtection = null;
3087         }
3088
3089         /**
3090          * Purge expired restrictions from the page_restrictions table
3091          *
3092          * This will purge no more than $wgUpdateRowsPerQuery page_restrictions rows
3093          */
3094         static function purgeExpiredRestrictions() {
3095                 if ( wfReadOnly() ) {
3096                         return;
3097                 }
3098
3099                 DeferredUpdates::addUpdate( new AtomicSectionUpdate(
3100                         wfGetDB( DB_MASTER ),
3101                         __METHOD__,
3102                         function ( IDatabase $dbw, $fname ) {
3103                                 $config = MediaWikiServices::getInstance()->getMainConfig();
3104                                 $ids = $dbw->selectFieldValues(
3105                                         'page_restrictions',
3106                                         'pr_id',
3107                                         [ 'pr_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ],
3108                                         $fname,
3109                                         [ 'LIMIT' => $config->get( 'UpdateRowsPerQuery' ) ] // T135470
3110                                 );
3111                                 if ( $ids ) {
3112                                         $dbw->delete( 'page_restrictions', [ 'pr_id' => $ids ], $fname );
3113                                 }
3114                         }
3115                 ) );
3116
3117                 DeferredUpdates::addUpdate( new AtomicSectionUpdate(
3118                         wfGetDB( DB_MASTER ),
3119                         __METHOD__,
3120                         function ( IDatabase $dbw, $fname ) {
3121                                 $dbw->delete(
3122                                         'protected_titles',
3123                                         [ 'pt_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ],
3124                                         $fname
3125                                 );
3126                         }
3127                 ) );
3128         }
3129
3130         /**
3131          * Does this have subpages?  (Warning, usually requires an extra DB query.)
3132          *
3133          * @return bool
3134          */
3135         public function hasSubpages() {
3136                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
3137                         # Duh
3138                         return false;
3139                 }
3140
3141                 # We dynamically add a member variable for the purpose of this method
3142                 # alone to cache the result.  There's no point in having it hanging
3143                 # around uninitialized in every Title object; therefore we only add it
3144                 # if needed and don't declare it statically.
3145                 if ( $this->mHasSubpages === null ) {
3146                         $this->mHasSubpages = false;
3147                         $subpages = $this->getSubpages( 1 );
3148                         if ( $subpages instanceof TitleArray ) {
3149                                 $this->mHasSubpages = (bool)$subpages->count();
3150                         }
3151                 }
3152
3153                 return $this->mHasSubpages;
3154         }
3155
3156         /**
3157          * Get all subpages of this page.
3158          *
3159          * @param int $limit Maximum number of subpages to fetch; -1 for no limit
3160          * @return TitleArray|array TitleArray, or empty array if this page's namespace
3161          *  doesn't allow subpages
3162          */
3163         public function getSubpages( $limit = -1 ) {
3164                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3165                         return [];
3166                 }
3167
3168                 $dbr = wfGetDB( DB_REPLICA );
3169                 $conds['page_namespace'] = $this->getNamespace();
3170                 $conds[] = 'page_title ' . $dbr->buildLike( $this->getDBkey() . '/', $dbr->anyString() );
3171                 $options = [];
3172                 if ( $limit > -1 ) {
3173                         $options['LIMIT'] = $limit;
3174                 }
3175                 $this->mSubpages = TitleArray::newFromResult(
3176                         $dbr->select( 'page',
3177                                 [ 'page_id', 'page_namespace', 'page_title', 'page_is_redirect' ],
3178                                 $conds,
3179                                 __METHOD__,
3180                                 $options
3181                         )
3182                 );
3183                 return $this->mSubpages;
3184         }
3185
3186         /**
3187          * Is there a version of this page in the deletion archive?
3188          *
3189          * @return int The number of archived revisions
3190          */
3191         public function isDeleted() {
3192                 if ( $this->getNamespace() < 0 ) {
3193                         $n = 0;
3194                 } else {
3195                         $dbr = wfGetDB( DB_REPLICA );
3196
3197                         $n = $dbr->selectField( 'archive', 'COUNT(*)',
3198                                 [ 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ],
3199                                 __METHOD__
3200                         );
3201                         if ( $this->getNamespace() == NS_FILE ) {
3202                                 $n += $dbr->selectField( 'filearchive', 'COUNT(*)',
3203                                         [ 'fa_name' => $this->getDBkey() ],
3204                                         __METHOD__
3205                                 );
3206                         }
3207                 }
3208                 return (int)$n;
3209         }
3210
3211         /**
3212          * Is there a version of this page in the deletion archive?
3213          *
3214          * @return bool
3215          */
3216         public function isDeletedQuick() {
3217                 if ( $this->getNamespace() < 0 ) {
3218                         return false;
3219                 }
3220                 $dbr = wfGetDB( DB_REPLICA );
3221                 $deleted = (bool)$dbr->selectField( 'archive', '1',
3222                         [ 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ],
3223                         __METHOD__
3224                 );
3225                 if ( !$deleted && $this->getNamespace() == NS_FILE ) {
3226                         $deleted = (bool)$dbr->selectField( 'filearchive', '1',
3227                                 [ 'fa_name' => $this->getDBkey() ],
3228                                 __METHOD__
3229                         );
3230                 }
3231                 return $deleted;
3232         }
3233
3234         /**
3235          * Get the article ID for this Title from the link cache,
3236          * adding it if necessary
3237          *
3238          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select
3239          *  for update
3240          * @return int The ID
3241          */
3242         public function getArticleID( $flags = 0 ) {
3243                 if ( $this->getNamespace() < 0 ) {
3244                         $this->mArticleID = 0;
3245                         return $this->mArticleID;
3246                 }
3247                 $linkCache = LinkCache::singleton();
3248                 if ( $flags & self::GAID_FOR_UPDATE ) {
3249                         $oldUpdate = $linkCache->forUpdate( true );
3250                         $linkCache->clearLink( $this );
3251                         $this->mArticleID = $linkCache->addLinkObj( $this );
3252                         $linkCache->forUpdate( $oldUpdate );
3253                 } else {
3254                         if ( -1 == $this->mArticleID ) {
3255                                 $this->mArticleID = $linkCache->addLinkObj( $this );
3256                         }
3257                 }
3258                 return $this->mArticleID;
3259         }
3260
3261         /**
3262          * Is this an article that is a redirect page?
3263          * Uses link cache, adding it if necessary
3264          *
3265          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3266          * @return bool
3267          */
3268         public function isRedirect( $flags = 0 ) {
3269                 if ( !is_null( $this->mRedirect ) ) {
3270                         return $this->mRedirect;
3271                 }
3272                 if ( !$this->getArticleID( $flags ) ) {
3273                         $this->mRedirect = false;
3274                         return $this->mRedirect;
3275                 }
3276
3277                 $linkCache = LinkCache::singleton();
3278                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3279                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'redirect' );
3280                 if ( $cached === null ) {
3281                         # Trust LinkCache's state over our own
3282                         # LinkCache is telling us that the page doesn't exist, despite there being cached
3283                         # data relating to an existing page in $this->mArticleID. Updaters should clear
3284                         # LinkCache as appropriate, or use $flags = Title::GAID_FOR_UPDATE. If that flag is
3285                         # set, then LinkCache will definitely be up to date here, since getArticleID() forces
3286                         # LinkCache to refresh its data from the master.
3287                         $this->mRedirect = false;
3288                         return $this->mRedirect;
3289                 }
3290
3291                 $this->mRedirect = (bool)$cached;
3292
3293                 return $this->mRedirect;
3294         }
3295
3296         /**
3297          * What is the length of this page?
3298          * Uses link cache, adding it if necessary
3299          *
3300          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3301          * @return int
3302          */
3303         public function getLength( $flags = 0 ) {
3304                 if ( $this->mLength != -1 ) {
3305                         return $this->mLength;
3306                 }
3307                 if ( !$this->getArticleID( $flags ) ) {
3308                         $this->mLength = 0;
3309                         return $this->mLength;
3310                 }
3311                 $linkCache = LinkCache::singleton();
3312                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3313                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'length' );
3314                 if ( $cached === null ) {
3315                         # Trust LinkCache's state over our own, as for isRedirect()
3316                         $this->mLength = 0;
3317                         return $this->mLength;
3318                 }
3319
3320                 $this->mLength = intval( $cached );
3321
3322                 return $this->mLength;
3323         }
3324
3325         /**
3326          * What is the page_latest field for this page?
3327          *
3328          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3329          * @return int Int or 0 if the page doesn't exist
3330          */
3331         public function getLatestRevID( $flags = 0 ) {
3332                 if ( !( $flags & Title::GAID_FOR_UPDATE ) && $this->mLatestID !== false ) {
3333                         return intval( $this->mLatestID );
3334                 }
3335                 if ( !$this->getArticleID( $flags ) ) {
3336                         $this->mLatestID = 0;
3337                         return $this->mLatestID;
3338                 }
3339                 $linkCache = LinkCache::singleton();
3340                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3341                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'revision' );
3342                 if ( $cached === null ) {
3343                         # Trust LinkCache's state over our own, as for isRedirect()
3344                         $this->mLatestID = 0;
3345                         return $this->mLatestID;
3346                 }
3347
3348                 $this->mLatestID = intval( $cached );
3349
3350                 return $this->mLatestID;
3351         }
3352
3353         /**
3354          * This clears some fields in this object, and clears any associated
3355          * keys in the "bad links" section of the link cache.
3356          *
3357          * - This is called from WikiPage::doEditContent() and WikiPage::insertOn() to allow
3358          * loading of the new page_id. It's also called from
3359          * WikiPage::doDeleteArticleReal()
3360          *
3361          * @param int $newid The new Article ID
3362          */
3363         public function resetArticleID( $newid ) {
3364                 $linkCache = LinkCache::singleton();
3365                 $linkCache->clearLink( $this );
3366
3367                 if ( $newid === false ) {
3368                         $this->mArticleID = -1;
3369                 } else {
3370                         $this->mArticleID = intval( $newid );
3371                 }
3372                 $this->mRestrictionsLoaded = false;
3373                 $this->mRestrictions = [];
3374                 $this->mOldRestrictions = false;
3375                 $this->mRedirect = null;
3376                 $this->mLength = -1;
3377                 $this->mLatestID = false;
3378                 $this->mContentModel = false;
3379                 $this->mEstimateRevisions = null;
3380                 $this->mPageLanguage = false;
3381                 $this->mDbPageLanguage = false;
3382                 $this->mIsBigDeletion = null;
3383         }
3384
3385         public static function clearCaches() {
3386                 $linkCache = LinkCache::singleton();
3387                 $linkCache->clear();
3388
3389                 $titleCache = self::getTitleCache();
3390                 $titleCache->clear();
3391         }
3392
3393         /**
3394          * Capitalize a text string for a title if it belongs to a namespace that capitalizes
3395          *
3396          * @param string $text Containing title to capitalize
3397          * @param int $ns Namespace index, defaults to NS_MAIN
3398          * @return string Containing capitalized title
3399          */
3400         public static function capitalize( $text, $ns = NS_MAIN ) {
3401                 global $wgContLang;
3402
3403                 if ( MWNamespace::isCapitalized( $ns ) ) {
3404                         return $wgContLang->ucfirst( $text );
3405                 } else {
3406                         return $text;
3407                 }
3408         }
3409
3410         /**
3411          * Secure and split - main initialisation function for this object
3412          *
3413          * Assumes that mDbkeyform has been set, and is urldecoded
3414          * and uses underscores, but not otherwise munged.  This function
3415          * removes illegal characters, splits off the interwiki and
3416          * namespace prefixes, sets the other forms, and canonicalizes
3417          * everything.
3418          *
3419          * @throws MalformedTitleException On invalid titles
3420          * @return bool True on success
3421          */
3422         private function secureAndSplit() {
3423                 # Initialisation
3424                 $this->mInterwiki = '';
3425                 $this->mFragment = '';
3426                 $this->mNamespace = $this->mDefaultNamespace; # Usually NS_MAIN
3427
3428                 $dbkey = $this->mDbkeyform;
3429
3430                 // @note: splitTitleString() is a temporary hack to allow MediaWikiTitleCodec to share
3431                 //        the parsing code with Title, while avoiding massive refactoring.
3432                 // @todo: get rid of secureAndSplit, refactor parsing code.
3433                 // @note: getTitleParser() returns a TitleParser implementation which does not have a
3434                 //        splitTitleString method, but the only implementation (MediaWikiTitleCodec) does
3435                 $titleCodec = MediaWikiServices::getInstance()->getTitleParser();
3436                 // MalformedTitleException can be thrown here
3437                 $parts = $titleCodec->splitTitleString( $dbkey, $this->getDefaultNamespace() );
3438
3439                 # Fill fields
3440                 $this->setFragment( '#' . $parts['fragment'] );
3441                 $this->mInterwiki = $parts['interwiki'];
3442                 $this->mLocalInterwiki = $parts['local_interwiki'];
3443                 $this->mNamespace = $parts['namespace'];
3444                 $this->mUserCaseDBKey = $parts['user_case_dbkey'];
3445
3446                 $this->mDbkeyform = $parts['dbkey'];
3447                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
3448                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
3449
3450                 # We already know that some pages won't be in the database!
3451                 if ( $this->isExternal() || $this->isSpecialPage() ) {
3452                         $this->mArticleID = 0;
3453                 }
3454
3455                 return true;
3456         }
3457
3458         /**
3459          * Get an array of Title objects linking to this Title
3460          * Also stores the IDs in the link cache.
3461          *
3462          * WARNING: do not use this function on arbitrary user-supplied titles!
3463          * On heavily-used templates it will max out the memory.
3464          *
3465          * @param array $options May be FOR UPDATE
3466          * @param string $table Table name
3467          * @param string $prefix Fields prefix
3468          * @return Title[] Array of Title objects linking here
3469          */
3470         public function getLinksTo( $options = [], $table = 'pagelinks', $prefix = 'pl' ) {
3471                 if ( count( $options ) > 0 ) {
3472                         $db = wfGetDB( DB_MASTER );
3473                 } else {
3474                         $db = wfGetDB( DB_REPLICA );
3475                 }
3476
3477                 $res = $db->select(
3478                         [ 'page', $table ],
3479                         self::getSelectFields(),
3480                         [
3481                                 "{$prefix}_from=page_id",
3482                                 "{$prefix}_namespace" => $this->getNamespace(),
3483                                 "{$prefix}_title" => $this->getDBkey() ],
3484                         __METHOD__,
3485                         $options
3486                 );
3487
3488                 $retVal = [];
3489                 if ( $res->numRows() ) {
3490                         $linkCache = LinkCache::singleton();
3491                         foreach ( $res as $row ) {
3492                                 $titleObj = Title::makeTitle( $row->page_namespace, $row->page_title );
3493                                 if ( $titleObj ) {
3494                                         $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3495                                         $retVal[] = $titleObj;
3496                                 }
3497                         }
3498                 }
3499                 return $retVal;
3500         }
3501
3502         /**
3503          * Get an array of Title objects using this Title as a template
3504          * Also stores the IDs in the link cache.
3505          *
3506          * WARNING: do not use this function on arbitrary user-supplied titles!
3507          * On heavily-used templates it will max out the memory.
3508          *
3509          * @param array $options Query option to Database::select()
3510          * @return Title[] Array of Title the Title objects linking here
3511          */
3512         public function getTemplateLinksTo( $options = [] ) {
3513                 return $this->getLinksTo( $options, 'templatelinks', 'tl' );
3514         }
3515
3516         /**
3517          * Get an array of Title objects linked from this Title
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          * @param string $table Table name
3525          * @param string $prefix Fields prefix
3526          * @return array Array of Title objects linking here
3527          */
3528         public function getLinksFrom( $options = [], $table = 'pagelinks', $prefix = 'pl' ) {
3529                 $id = $this->getArticleID();
3530
3531                 # If the page doesn't exist; there can't be any link from this page
3532                 if ( !$id ) {
3533                         return [];
3534                 }
3535
3536                 $db = wfGetDB( DB_REPLICA );
3537
3538                 $blNamespace = "{$prefix}_namespace";
3539                 $blTitle = "{$prefix}_title";
3540
3541                 $res = $db->select(
3542                         [ $table, 'page' ],
3543                         array_merge(
3544                                 [ $blNamespace, $blTitle ],
3545                                 WikiPage::selectFields()
3546                         ),
3547                         [ "{$prefix}_from" => $id ],
3548                         __METHOD__,
3549                         $options,
3550                         [ 'page' => [
3551                                 'LEFT JOIN',
3552                                 [ "page_namespace=$blNamespace", "page_title=$blTitle" ]
3553                         ] ]
3554                 );
3555
3556                 $retVal = [];
3557                 $linkCache = LinkCache::singleton();
3558                 foreach ( $res as $row ) {
3559                         if ( $row->page_id ) {
3560                                 $titleObj = Title::newFromRow( $row );
3561                         } else {
3562                                 $titleObj = Title::makeTitle( $row->$blNamespace, $row->$blTitle );
3563                                 $linkCache->addBadLinkObj( $titleObj );
3564                         }
3565                         $retVal[] = $titleObj;
3566                 }
3567
3568                 return $retVal;
3569         }
3570
3571         /**
3572          * Get an array of Title objects used on this Title as a template
3573          * Also stores the IDs in the link cache.
3574          *
3575          * WARNING: do not use this function on arbitrary user-supplied titles!
3576          * On heavily-used templates it will max out the memory.
3577          *
3578          * @param array $options May be FOR UPDATE
3579          * @return Title[] Array of Title the Title objects used here
3580          */
3581         public function getTemplateLinksFrom( $options = [] ) {
3582                 return $this->getLinksFrom( $options, 'templatelinks', 'tl' );
3583         }
3584
3585         /**
3586          * Get an array of Title objects referring to non-existent articles linked
3587          * from this page.