includes/Title.php

   1 <?php
   2 /**
   3  * Representation of a title within %MediaWiki.
   4  *
   5  * See title.txt
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License along
  18  * with this program; if not, write to the Free Software Foundation, Inc.,
  19  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  20  * http://www.gnu.org/copyleft/gpl.html
  21  *
  22  * @file
  23  */
  24
  25 use Wikimedia\Rdbms\Database;
  26 use Wikimedia\Rdbms\IDatabase;
  27 use MediaWiki\Linker\LinkTarget;
  28 use MediaWiki\Interwiki\InterwikiLookup;
  29 use MediaWiki\MediaWikiServices;
  30
  31 /**
  32  * Represents a title within MediaWiki.
  33  * Optionally may contain an interwiki designation or namespace.
  34  * @note This class can fetch various kinds of data from the database;
  35  *       however, it does so inefficiently.
  36  * @note Consider using a TitleValue object instead. TitleValue is more lightweight
  37  *       and does not rely on global state or the database.
  38  */
  39 class Title implements LinkTarget {
  40         /** @var HashBagOStuff */
  41         static private $titleCache = null;
  42
  43         /**
  44          * Title::newFromText maintains a cache to avoid expensive re-normalization of
  45          * commonly used titles. On a batch operation this can become a memory leak
  46          * if not bounded. After hitting this many titles reset the cache.
  47          */
  48         const CACHE_MAX = 1000;
  49
  50         /**
  51          * Used to be GAID_FOR_UPDATE define. Used with getArticleID() and friends
  52          * to use the master DB
  53          */
  54         const GAID_FOR_UPDATE = 1;
  55
  56         /**
  57          * @name Private member variables
  58          * Please use the accessor functions instead.
  59          * @private
  60          */
  61         // @{
  62
  63         /** @var string Text form (spaces not underscores) of the main part */
  64         public $mTextform = '';
  65
  66         /** @var string URL-encoded form of the main part */
  67         public $mUrlform = '';
  68
  69         /** @var string Main part with underscores */
  70         public $mDbkeyform = '';
  71
  72         /** @var string Database key with the initial letter in the case specified by the user */
  73         protected $mUserCaseDBKey;
  74
  75         /** @var int Namespace index, i.e. one of the NS_xxxx constants */
  76         public $mNamespace = NS_MAIN;
  77
  78         /** @var string Interwiki prefix */
  79         public $mInterwiki = '';
  80
  81         /** @var bool Was this Title created from a string with a local interwiki prefix? */
  82         private $mLocalInterwiki = false;
  83
  84         /** @var string Title fragment (i.e. the bit after the #) */
  85         public $mFragment = '';
  86
  87         /** @var int Article ID, fetched from the link cache on demand */
  88         public $mArticleID = -1;
  89
  90         /** @var bool|int ID of most recent revision */
  91         protected $mLatestID = false;
  92
  93         /**
  94          * @var bool|string ID of the page's content model, i.e. one of the
  95          *   CONTENT_MODEL_XXX constants
  96          */
  97         private $mContentModel = false;
  98
  99         /**
 100          * @var bool If a content model was forced via setContentModel()
 101          *   this will be true to avoid having other code paths reset it
 102          */
 103         private $mForcedContentModel = false;
 104
 105         /** @var int Estimated number of revisions; null of not loaded */
 106         private $mEstimateRevisions;
 107
 108         /** @var array Array of groups allowed to edit this article */
 109         public $mRestrictions = [];
 110
 111         /** @var string|bool */
 112         protected $mOldRestrictions = false;
 113
 114         /** @var bool Cascade restrictions on this page to included templates and images? */
 115         public $mCascadeRestriction;
 116
 117         /** Caching the results of getCascadeProtectionSources */
 118         public $mCascadingRestrictions;
 119
 120         /** @var array When do the restrictions on this page expire? */
 121         protected $mRestrictionsExpiry = [];
 122
 123         /** @var bool Are cascading restrictions in effect on this page? */
 124         protected $mHasCascadingRestrictions;
 125
 126         /** @var array Where are the cascading restrictions coming from on this page? */
 127         public $mCascadeSources;
 128
 129         /** @var bool Boolean for initialisation on demand */
 130         public $mRestrictionsLoaded = false;
 131
 132         /** @var string Text form including namespace/interwiki, initialised on demand */
 133         protected $mPrefixedText = null;
 134
 135         /** @var mixed Cached value for getTitleProtection (create protection) */
 136         public $mTitleProtection;
 137
 138         /**
 139          * @var int Namespace index when there is no namespace. Don't change the
 140          *   following default, NS_MAIN is hardcoded in several places. See T2696.
 141          *   Zero except in {{transclusion}} tags.
 142          */
 143         public $mDefaultNamespace = NS_MAIN;
 144
 145         /** @var int The page length, 0 for special pages */
 146         protected $mLength = -1;
 147
 148         /** @var null Is the article at this title a redirect? */
 149         public $mRedirect = null;
 150
 151         /** @var array Associative array of user ID -> timestamp/false */
 152         private $mNotificationTimestamp = [];
 153
 154         /** @var bool Whether a page has any subpages */
 155         private $mHasSubpages;
 156
 157         /** @var bool The (string) language code of the page's language and content code. */
 158         private $mPageLanguage = false;
 159
 160         /** @var string|bool|null The page language code from the database, null if not saved in
 161          * the database or false if not loaded, yet. */
 162         private $mDbPageLanguage = false;
 163
 164         /** @var TitleValue A corresponding TitleValue object */
 165         private $mTitleValue = null;
 166
 167         /** @var bool Would deleting this page be a big deletion? */
 168         private $mIsBigDeletion = null;
 169         // @}
 170
 171         /**
 172          * B/C kludge: provide a TitleParser for use by Title.
 173          * Ideally, Title would have no methods that need this.
 174          * Avoid usage of this singleton by using TitleValue
 175          * and the associated services when possible.
 176          *
 177          * @return TitleFormatter
 178          */
 179         private static function getTitleFormatter() {
 180                 return MediaWikiServices::getInstance()->getTitleFormatter();
 181         }
 182
 183         /**
 184          * B/C kludge: provide an InterwikiLookup for use by Title.
 185          * Ideally, Title would have no methods that need this.
 186          * Avoid usage of this singleton by using TitleValue
 187          * and the associated services when possible.
 188          *
 189          * @return InterwikiLookup
 190          */
 191         private static function getInterwikiLookup() {
 192                 return MediaWikiServices::getInstance()->getInterwikiLookup();
 193         }
 194
 195         /**
 196          * @access protected
 197          */
 198         function __construct() {
 199         }
 200
 201         /**
 202          * Create a new Title from a prefixed DB key
 203          *
 204          * @param string $key The database key, which has underscores
 205          *      instead of spaces, possibly including namespace and
 206          *      interwiki prefixes
 207          * @return Title|null Title, or null on an error
 208          */
 209         public static function newFromDBkey( $key ) {
 210                 $t = new Title();
 211                 $t->mDbkeyform = $key;
 212
 213                 try {
 214                         $t->secureAndSplit();
 215                         return $t;
 216                 } catch ( MalformedTitleException $ex ) {
 217                         return null;
 218                 }
 219         }
 220
 221         /**
 222          * Create a new Title from a TitleValue
 223          *
 224          * @param TitleValue $titleValue Assumed to be safe.
 225          *
 226          * @return Title
 227          */
 228         public static function newFromTitleValue( TitleValue $titleValue ) {
 229                 return self::newFromLinkTarget( $titleValue );
 230         }
 231
 232         /**
 233          * Create a new Title from a LinkTarget
 234          *
 235          * @param LinkTarget $linkTarget Assumed to be safe.
 236          *
 237          * @return Title
 238          */
 239         public static function newFromLinkTarget( LinkTarget $linkTarget ) {
 240                 if ( $linkTarget instanceof Title ) {
 241                         // Special case if it's already a Title object
 242                         return $linkTarget;
 243                 }
 244                 return self::makeTitle(
 245                         $linkTarget->getNamespace(),
 246                         $linkTarget->getText(),
 247                         $linkTarget->getFragment(),
 248                         $linkTarget->getInterwiki()
 249                 );
 250         }
 251
 252         /**
 253          * Create a new Title from text, such as what one would find in a link. De-
 254          * codes any HTML entities in the text.
 255          *
 256          * @param string|int|null $text The link text; spaces, prefixes, and an
 257          *   initial ':' indicating the main namespace are accepted.
 258          * @param int $defaultNamespace The namespace to use if none is specified
 259          *   by a prefix.  If you want to force a specific namespace even if
 260          *   $text might begin with a namespace prefix, use makeTitle() or
 261          *   makeTitleSafe().
 262          * @throws InvalidArgumentException
 263          * @return Title|null Title or null on an error.
 264          */
 265         public static function newFromText( $text, $defaultNamespace = NS_MAIN ) {
 266                 // DWIM: Integers can be passed in here when page titles are used as array keys.
 267                 if ( $text !== null && !is_string( $text ) && !is_int( $text ) ) {
 268                         throw new InvalidArgumentException( '$text must be a string.' );
 269                 }
 270                 if ( $text === null ) {
 271                         return null;
 272                 }
 273
 274                 try {
 275                         return self::newFromTextThrow( strval( $text ), $defaultNamespace );
 276                 } catch ( MalformedTitleException $ex ) {
 277                         return null;
 278                 }
 279         }
 280
 281         /**
 282          * Like Title::newFromText(), but throws MalformedTitleException when the title is invalid,
 283          * rather than returning null.
 284          *
 285          * The exception subclasses encode detailed information about why the title is invalid.
 286          *
 287          * @see Title::newFromText
 288          *
 289          * @since 1.25
 290          * @param string $text Title text to check
 291          * @param int $defaultNamespace
 292          * @throws MalformedTitleException If the title is invalid
 293          * @return Title
 294          */
 295         public static function newFromTextThrow( $text, $defaultNamespace = NS_MAIN ) {
 296                 if ( is_object( $text ) ) {
 297                         throw new MWException( '$text must be a string, given an object' );
 298                 }
 299
 300                 $titleCache = self::getTitleCache();
 301
 302                 // Wiki pages often contain multiple links to the same page.
 303                 // Title normalization and parsing can become expensive on pages with many
 304                 // links, so we can save a little time by caching them.
 305                 // In theory these are value objects and won't get changed...
 306                 if ( $defaultNamespace == NS_MAIN ) {
 307                         $t = $titleCache->get( $text );
 308                         if ( $t ) {
 309                                 return $t;
 310                         }
 311                 }
 312
 313                 // Convert things like &eacute; &#257; or &#x3017; into normalized (T16952) text
 314                 $filteredText = Sanitizer::decodeCharReferencesAndNormalize( $text );
 315
 316                 $t = new Title();
 317                 $t->mDbkeyform = strtr( $filteredText, ' ', '_' );
 318                 $t->mDefaultNamespace = intval( $defaultNamespace );
 319
 320                 $t->secureAndSplit();
 321                 if ( $defaultNamespace == NS_MAIN ) {
 322                         $titleCache->set( $text, $t );
 323                 }
 324                 return $t;
 325         }
 326
 327         /**
 328          * THIS IS NOT THE FUNCTION YOU WANT. Use Title::newFromText().
 329          *
 330          * Example of wrong and broken code:
 331          * $title = Title::newFromURL( $wgRequest->getVal( 'title' ) );
 332          *
 333          * Example of right code:
 334          * $title = Title::newFromText( $wgRequest->getVal( 'title' ) );
 335          *
 336          * Create a new Title from URL-encoded text. Ensures that
 337          * the given title's length does not exceed the maximum.
 338          *
 339          * @param string $url The title, as might be taken from a URL
 340          * @return Title|null The new object, or null on an error
 341          */
 342         public static function newFromURL( $url ) {
 343                 $t = new Title();
 344
 345                 # For compatibility with old buggy URLs. "+" is usually not valid in titles,
 346                 # but some URLs used it as a space replacement and they still come
 347                 # from some external search tools.
 348                 if ( strpos( self::legalChars(), '+' ) === false ) {
 349                         $url = strtr( $url, '+', ' ' );
 350                 }
 351
 352                 $t->mDbkeyform = strtr( $url, ' ', '_' );
 353
 354                 try {
 355                         $t->secureAndSplit();
 356                         return $t;
 357                 } catch ( MalformedTitleException $ex ) {
 358                         return null;
 359                 }
 360         }
 361
 362         /**
 363          * @return HashBagOStuff
 364          */
 365         private static function getTitleCache() {
 366                 if ( self::$titleCache == null ) {
 367                         self::$titleCache = new HashBagOStuff( [ 'maxKeys' => self::CACHE_MAX ] );
 368                 }
 369                 return self::$titleCache;
 370         }
 371
 372         /**
 373          * Returns a list of fields that are to be selected for initializing Title
 374          * objects or LinkCache entries. Uses $wgContentHandlerUseDB to determine
 375          * whether to include page_content_model.
 376          *
 377          * @return array
 378          */
 379         protected static function getSelectFields() {
 380                 global $wgContentHandlerUseDB, $wgPageLanguageUseDB;
 381
 382                 $fields = [
 383                         'page_namespace', 'page_title', 'page_id',
 384                         'page_len', 'page_is_redirect', 'page_latest',
 385                 ];
 386
 387                 if ( $wgContentHandlerUseDB ) {
 388                         $fields[] = 'page_content_model';
 389                 }
 390
 391                 if ( $wgPageLanguageUseDB ) {
 392                         $fields[] = 'page_lang';
 393                 }
 394
 395                 return $fields;
 396         }
 397
 398         /**
 399          * Create a new Title from an article ID
 400          *
 401          * @param int $id The page_id corresponding to the Title to create
 402          * @param int $flags Use Title::GAID_FOR_UPDATE to use master
 403          * @return Title|null The new object, or null on an error
 404          */
 405         public static function newFromID( $id, $flags = 0 ) {
 406                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_REPLICA );
 407                 $row = $db->selectRow(
 408                         'page',
 409                         self::getSelectFields(),
 410                         [ 'page_id' => $id ],
 411                         __METHOD__
 412                 );
 413                 if ( $row !== false ) {
 414                         $title = self::newFromRow( $row );
 415                 } else {
 416                         $title = null;
 417                 }
 418                 return $title;
 419         }
 420
 421         /**
 422          * Make an array of titles from an array of IDs
 423          *
 424          * @param int[] $ids Array of IDs
 425          * @return Title[] Array of Titles
 426          */
 427         public static function newFromIDs( $ids ) {
 428                 if ( !count( $ids ) ) {
 429                         return [];
 430                 }
 431                 $dbr = wfGetDB( DB_REPLICA );
 432
 433                 $res = $dbr->select(
 434                         'page',
 435                         self::getSelectFields(),
 436                         [ 'page_id' => $ids ],
 437                         __METHOD__
 438                 );
 439
 440                 $titles = [];
 441                 foreach ( $res as $row ) {
 442                         $titles[] = self::newFromRow( $row );
 443                 }
 444                 return $titles;
 445         }
 446
 447         /**
 448          * Make a Title object from a DB row
 449          *
 450          * @param stdClass $row Object database row (needs at least page_title,page_namespace)
 451          * @return Title Corresponding Title
 452          */
 453         public static function newFromRow( $row ) {
 454                 $t = self::makeTitle( $row->page_namespace, $row->page_title );
 455                 $t->loadFromRow( $row );
 456                 return $t;
 457         }
 458
 459         /**
 460          * Load Title object fields from a DB row.
 461          * If false is given, the title will be treated as non-existing.
 462          *
 463          * @param stdClass|bool $row Database row
 464          */
 465         public function loadFromRow( $row ) {
 466                 if ( $row ) { // page found
 467                         if ( isset( $row->page_id ) ) {
 468                                 $this->mArticleID = (int)$row->page_id;
 469                         }
 470                         if ( isset( $row->page_len ) ) {
 471                                 $this->mLength = (int)$row->page_len;
 472                         }
 473                         if ( isset( $row->page_is_redirect ) ) {
 474                                 $this->mRedirect = (bool)$row->page_is_redirect;
 475                         }
 476                         if ( isset( $row->page_latest ) ) {
 477                                 $this->mLatestID = (int)$row->page_latest;
 478                         }
 479                         if ( !$this->mForcedContentModel && isset( $row->page_content_model ) ) {
 480                                 $this->mContentModel = strval( $row->page_content_model );
 481                         } elseif ( !$this->mForcedContentModel ) {
 482                                 $this->mContentModel = false; # initialized lazily in getContentModel()
 483                         }
 484                         if ( isset( $row->page_lang ) ) {
 485                                 $this->mDbPageLanguage = (string)$row->page_lang;
 486                         }
 487                         if ( isset( $row->page_restrictions ) ) {
 488                                 $this->mOldRestrictions = $row->page_restrictions;
 489                         }
 490                 } else { // page not found
 491                         $this->mArticleID = 0;
 492                         $this->mLength = 0;
 493                         $this->mRedirect = false;
 494                         $this->mLatestID = 0;
 495                         if ( !$this->mForcedContentModel ) {
 496                                 $this->mContentModel = false; # initialized lazily in getContentModel()
 497                         }
 498                 }
 499         }
 500
 501         /**
 502          * Create a new Title from a namespace index and a DB key.
 503          * It's assumed that $ns and $title are *valid*, for instance when
 504          * they came directly from the database or a special page name.
 505          * For convenience, spaces are converted to underscores so that
 506          * eg user_text fields can be used directly.
 507          *
 508          * @param int $ns The namespace of the article
 509          * @param string $title The unprefixed database key form
 510          * @param string $fragment The link fragment (after the "#")
 511          * @param string $interwiki The interwiki prefix
 512          * @return Title The new object
 513          */
 514         public static function makeTitle( $ns, $title, $fragment = '', $interwiki = '' ) {
 515                 $t = new Title();
 516                 $t->mInterwiki = $interwiki;
 517                 $t->mFragment = $fragment;
 518                 $t->mNamespace = $ns = intval( $ns );
 519                 $t->mDbkeyform = strtr( $title, ' ', '_' );
 520                 $t->mArticleID = ( $ns >= 0 ) ? -1 : 0;
 521                 $t->mUrlform = wfUrlencode( $t->mDbkeyform );
 522                 $t->mTextform = strtr( $title, '_', ' ' );
 523                 $t->mContentModel = false; # initialized lazily in getContentModel()
 524                 return $t;
 525         }
 526
 527         /**
 528          * Create a new Title from a namespace index and a DB key.
 529          * The parameters will be checked for validity, which is a bit slower
 530          * than makeTitle() but safer for user-provided data.
 531          *
 532          * @param int $ns The namespace of the article
 533          * @param string $title Database key form
 534          * @param string $fragment The link fragment (after the "#")
 535          * @param string $interwiki Interwiki prefix
 536          * @return Title|null The new object, or null on an error
 537          */
 538         public static function makeTitleSafe( $ns, $title, $fragment = '', $interwiki = '' ) {
 539                 if ( !MWNamespace::exists( $ns ) ) {
 540                         return null;
 541                 }
 542
 543                 $t = new Title();
 544                 $t->mDbkeyform = self::makeName( $ns, $title, $fragment, $interwiki, true );
 545
 546                 try {
 547                         $t->secureAndSplit();
 548                         return $t;
 549                 } catch ( MalformedTitleException $ex ) {
 550                         return null;
 551                 }
 552         }
 553
 554         /**
 555          * Create a new Title for the Main Page
 556          *
 557          * @return Title The new object
 558          */
 559         public static function newMainPage() {
 560                 $title = self::newFromText( wfMessage( 'mainpage' )->inContentLanguage()->text() );
 561                 // Don't give fatal errors if the message is broken
 562                 if ( !$title ) {
 563                         $title = self::newFromText( 'Main Page' );
 564                 }
 565                 return $title;
 566         }
 567
 568         /**
 569          * Get the prefixed DB key associated with an ID
 570          *
 571          * @param int $id The page_id of the article
 572          * @return Title|null An object representing the article, or null if no such article was found
 573          */
 574         public static function nameOf( $id ) {
 575                 $dbr = wfGetDB( DB_REPLICA );
 576
 577                 $s = $dbr->selectRow(
 578                         'page',
 579                         [ 'page_namespace', 'page_title' ],
 580                         [ 'page_id' => $id ],
 581                         __METHOD__
 582                 );
 583                 if ( $s === false ) {
 584                         return null;
 585                 }
 586
 587                 $n = self::makeName( $s->page_namespace, $s->page_title );
 588                 return $n;
 589         }
 590
 591         /**
 592          * Get a regex character class describing the legal characters in a link
 593          *
 594          * @return string The list of characters, not delimited
 595          */
 596         public static function legalChars() {
 597                 global $wgLegalTitleChars;
 598                 return $wgLegalTitleChars;
 599         }
 600
 601         /**
 602          * Returns a simple regex that will match on characters and sequences invalid in titles.
 603          * Note that this doesn't pick up many things that could be wrong with titles, but that
 604          * replacing this regex with something valid will make many titles valid.
 605          *
 606          * @deprecated since 1.25, use MediaWikiTitleCodec::getTitleInvalidRegex() instead
 607          *
 608          * @return string Regex string
 609          */
 610         static function getTitleInvalidRegex() {
 611                 wfDeprecated( __METHOD__, '1.25' );
 612                 return MediaWikiTitleCodec::getTitleInvalidRegex();
 613         }
 614
 615         /**
 616          * Utility method for converting a character sequence from bytes to Unicode.
 617          *
 618          * Primary usecase being converting $wgLegalTitleChars to a sequence usable in
 619          * javascript, as PHP uses UTF-8 bytes where javascript uses Unicode code units.
 620          *
 621          * @param string $byteClass
 622          * @return string
 623          */
 624         public static function convertByteClassToUnicodeClass( $byteClass ) {
 625                 $length = strlen( $byteClass );
 626                 // Input token queue
 627                 $x0 = $x1 = $x2 = '';
 628                 // Decoded queue
 629                 $d0 = $d1 = $d2 = '';
 630                 // Decoded integer codepoints
 631                 $ord0 = $ord1 = $ord2 = 0;
 632                 // Re-encoded queue
 633                 $r0 = $r1 = $r2 = '';
 634                 // Output
 635                 $out = '';
 636                 // Flags
 637                 $allowUnicode = false;
 638                 for ( $pos = 0; $pos < $length; $pos++ ) {
 639                         // Shift the queues down
 640                         $x2 = $x1;
 641                         $x1 = $x0;
 642                         $d2 = $d1;
 643                         $d1 = $d0;
 644                         $ord2 = $ord1;
 645                         $ord1 = $ord0;
 646                         $r2 = $r1;
 647                         $r1 = $r0;
 648                         // Load the current input token and decoded values
 649                         $inChar = $byteClass[$pos];
 650                         if ( $inChar == '\\' ) {
 651                                 if ( preg_match( '/x([0-9a-fA-F]{2})/A', $byteClass, $m, 0, $pos + 1 ) ) {
 652                                         $x0 = $inChar . $m[0];
 653                                         $d0 = chr( hexdec( $m[1] ) );
 654                                         $pos += strlen( $m[0] );
 655                                 } elseif ( preg_match( '/[0-7]{3}/A', $byteClass, $m, 0, $pos + 1 ) ) {
 656                                         $x0 = $inChar . $m[0];
 657                                         $d0 = chr( octdec( $m[0] ) );
 658                                         $pos += strlen( $m[0] );
 659                                 } elseif ( $pos + 1 >= $length ) {
 660                                         $x0 = $d0 = '\\';
 661                                 } else {
 662                                         $d0 = $byteClass[$pos + 1];
 663                                         $x0 = $inChar . $d0;
 664                                         $pos += 1;
 665                                 }
 666                         } else {
 667                                 $x0 = $d0 = $inChar;
 668                         }
 669                         $ord0 = ord( $d0 );
 670                         // Load the current re-encoded value
 671                         if ( $ord0 < 32 || $ord0 == 0x7f ) {
 672                                 $r0 = sprintf( '\x%02x', $ord0 );
 673                         } elseif ( $ord0 >= 0x80 ) {
 674                                 // Allow unicode if a single high-bit character appears
 675                                 $r0 = sprintf( '\x%02x', $ord0 );
 676                                 $allowUnicode = true;
 677                         } elseif ( strpos( '-\\[]^', $d0 ) !== false ) {
 678                                 $r0 = '\\' . $d0;
 679                         } else {
 680                                 $r0 = $d0;
 681                         }
 682                         // Do the output
 683                         if ( $x0 !== '' && $x1 === '-' && $x2 !== '' ) {
 684                                 // Range
 685                                 if ( $ord2 > $ord0 ) {
 686                                         // Empty range
 687                                 } elseif ( $ord0 >= 0x80 ) {
 688                                         // Unicode range
 689                                         $allowUnicode = true;
 690                                         if ( $ord2 < 0x80 ) {
 691                                                 // Keep the non-unicode section of the range
 692                                                 $out .= "$r2-\\x7F";
 693                                         }
 694                                 } else {
 695                                         // Normal range
 696                                         $out .= "$r2-$r0";
 697                                 }
 698                                 // Reset state to the initial value
 699                                 $x0 = $x1 = $d0 = $d1 = $r0 = $r1 = '';
 700                         } elseif ( $ord2 < 0x80 ) {
 701                                 // ASCII character
 702                                 $out .= $r2;
 703                         }
 704                 }
 705                 if ( $ord1 < 0x80 ) {
 706                         $out .= $r1;
 707                 }
 708                 if ( $ord0 < 0x80 ) {
 709                         $out .= $r0;
 710                 }
 711                 if ( $allowUnicode ) {
 712                         $out .= '\u0080-\uFFFF';
 713                 }
 714                 return $out;
 715         }
 716
 717         /**
 718          * Make a prefixed DB key from a DB key and a namespace index
 719          *
 720          * @param int $ns Numerical representation of the namespace
 721          * @param string $title The DB key form the title
 722          * @param string $fragment The link fragment (after the "#")
 723          * @param string $interwiki The interwiki prefix
 724          * @param bool $canonicalNamespace If true, use the canonical name for
 725          *   $ns instead of the localized version.
 726          * @return string The prefixed form of the title
 727          */
 728         public static function makeName( $ns, $title, $fragment = '', $interwiki = '',
 729                 $canonicalNamespace = false
 730         ) {
 731                 global $wgContLang;
 732
 733                 if ( $canonicalNamespace ) {
 734                         $namespace = MWNamespace::getCanonicalName( $ns );
 735                 } else {
 736                         $namespace = $wgContLang->getNsText( $ns );
 737                 }
 738                 $name = $namespace == '' ? $title : "$namespace:$title";
 739                 if ( strval( $interwiki ) != '' ) {
 740                         $name = "$interwiki:$name";
 741                 }
 742                 if ( strval( $fragment ) != '' ) {
 743                         $name .= '#' . $fragment;
 744                 }
 745                 return $name;
 746         }
 747
 748         /**
 749          * Escape a text fragment, say from a link, for a URL
 750          *
 751          * @deprecated since 1.30, use Sanitizer::escapeIdForLink() or escapeIdForExternalInterwiki()
 752          *
 753          * @param string $fragment Containing a URL or link fragment (after the "#")
 754          * @return string Escaped string
 755          */
 756         static function escapeFragmentForURL( $fragment ) {
 757                 # Note that we don't urlencode the fragment.  urlencoded Unicode
 758                 # fragments appear not to work in IE (at least up to 7) or in at least
 759                 # one version of Opera 9.x.  The W3C validator, for one, doesn't seem
 760                 # to care if they aren't encoded.
 761                 return Sanitizer::escapeId( $fragment, 'noninitial' );
 762         }
 763
 764         /**
 765          * Callback for usort() to do title sorts by (namespace, title)
 766          *
 767          * @param LinkTarget $a
 768          * @param LinkTarget $b
 769          *
 770          * @return int Result of string comparison, or namespace comparison
 771          */
 772         public static function compare( LinkTarget $a, LinkTarget $b ) {
 773                 if ( $a->getNamespace() == $b->getNamespace() ) {
 774                         return strcmp( $a->getText(), $b->getText() );
 775                 } else {
 776                         return $a->getNamespace() - $b->getNamespace();
 777                 }
 778         }
 779
 780         /**
 781          * Determine whether the object refers to a page within
 782          * this project (either this wiki or a wiki with a local
 783          * interwiki, see https://www.mediawiki.org/wiki/Manual:Interwiki_table#iw_local )
 784          *
 785          * @return bool True if this is an in-project interwiki link or a wikilink, false otherwise
 786          */
 787         public function isLocal() {
 788                 if ( $this->isExternal() ) {
 789                         $iw = self::getInterwikiLookup()->fetch( $this->mInterwiki );
 790                         if ( $iw ) {
 791                                 return $iw->isLocal();
 792                         }
 793                 }
 794                 return true;
 795         }
 796
 797         /**
 798          * Is this Title interwiki?
 799          *
 800          * @return bool
 801          */
 802         public function isExternal() {
 803                 return $this->mInterwiki !== '';
 804         }
 805
 806         /**
 807          * Get the interwiki prefix
 808          *
 809          * Use Title::isExternal to check if a interwiki is set
 810          *
 811          * @return string Interwiki prefix
 812          */
 813         public function getInterwiki() {
 814                 return $this->mInterwiki;
 815         }
 816
 817         /**
 818          * Was this a local interwiki link?
 819          *
 820          * @return bool
 821          */
 822         public function wasLocalInterwiki() {
 823                 return $this->mLocalInterwiki;
 824         }
 825
 826         /**
 827          * Determine whether the object refers to a page within
 828          * this project and is transcludable.
 829          *
 830          * @return bool True if this is transcludable
 831          */
 832         public function isTrans() {
 833                 if ( !$this->isExternal() ) {
 834                         return false;
 835                 }
 836
 837                 return self::getInterwikiLookup()->fetch( $this->mInterwiki )->isTranscludable();
 838         }
 839
 840         /**
 841          * Returns the DB name of the distant wiki which owns the object.
 842          *
 843          * @return string|false The DB name
 844          */
 845         public function getTransWikiID() {
 846                 if ( !$this->isExternal() ) {
 847                         return false;
 848                 }
 849
 850                 return self::getInterwikiLookup()->fetch( $this->mInterwiki )->getWikiID();
 851         }
 852
 853         /**
 854          * Get a TitleValue object representing this Title.
 855          *
 856          * @note Not all valid Titles have a corresponding valid TitleValue
 857          * (e.g. TitleValues cannot represent page-local links that have a
 858          * fragment but no title text).
 859          *
 860          * @return TitleValue|null
 861          */
 862         public function getTitleValue() {
 863                 if ( $this->mTitleValue === null ) {
 864                         try {
 865                                 $this->mTitleValue = new TitleValue(
 866                                         $this->getNamespace(),
 867                                         $this->getDBkey(),
 868                                         $this->getFragment(),
 869                                         $this->getInterwiki()
 870                                 );
 871                         } catch ( InvalidArgumentException $ex ) {
 872                                 wfDebug( __METHOD__ . ': Can\'t create a TitleValue for [[' .
 873                                         $this->getPrefixedText() . ']]: ' . $ex->getMessage() . "\n" );
 874                         }
 875                 }
 876
 877                 return $this->mTitleValue;
 878         }
 879
 880         /**
 881          * Get the text form (spaces not underscores) of the main part
 882          *
 883          * @return string Main part of the title
 884          */
 885         public function getText() {
 886                 return $this->mTextform;
 887         }
 888
 889         /**
 890          * Get the URL-encoded form of the main part
 891          *
 892          * @return string Main part of the title, URL-encoded
 893          */
 894         public function getPartialURL() {
 895                 return $this->mUrlform;
 896         }
 897
 898         /**
 899          * Get the main part with underscores
 900          *
 901          * @return string Main part of the title, with underscores
 902          */
 903         public function getDBkey() {
 904                 return $this->mDbkeyform;
 905         }
 906
 907         /**
 908          * Get the DB key with the initial letter case as specified by the user
 909          *
 910          * @return string DB key
 911          */
 912         function getUserCaseDBKey() {
 913                 if ( !is_null( $this->mUserCaseDBKey ) ) {
 914                         return $this->mUserCaseDBKey;
 915                 } else {
 916                         // If created via makeTitle(), $this->mUserCaseDBKey is not set.
 917                         return $this->mDbkeyform;
 918                 }
 919         }
 920
 921         /**
 922          * Get the namespace index, i.e. one of the NS_xxxx constants.
 923          *
 924          * @return int Namespace index
 925          */
 926         public function getNamespace() {
 927                 return $this->mNamespace;
 928         }
 929
 930         /**
 931          * Get the page's content model id, see the CONTENT_MODEL_XXX constants.
 932          *
 933          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
 934          * @return string Content model id
 935          */
 936         public function getContentModel( $flags = 0 ) {
 937                 if ( !$this->mForcedContentModel
 938                         && ( !$this->mContentModel || $flags === self::GAID_FOR_UPDATE )
 939                         && $this->getArticleID( $flags )
 940                 ) {
 941                         $linkCache = LinkCache::singleton();
 942                         $linkCache->addLinkObj( $this ); # in case we already had an article ID
 943                         $this->mContentModel = $linkCache->getGoodLinkFieldObj( $this, 'model' );
 944                 }
 945
 946                 if ( !$this->mContentModel ) {
 947                         $this->mContentModel = ContentHandler::getDefaultModelFor( $this );
 948                 }
 949
 950                 return $this->mContentModel;
 951         }
 952
 953         /**
 954          * Convenience method for checking a title's content model name
 955          *
 956          * @param string $id The content model ID (use the CONTENT_MODEL_XXX constants).
 957          * @return bool True if $this->getContentModel() == $id
 958          */
 959         public function hasContentModel( $id ) {
 960                 return $this->getContentModel() == $id;
 961         }
 962
 963         /**
 964          * Set a proposed content model for the page for permissions
 965          * checking. This does not actually change the content model
 966          * of a title!
 967          *
 968          * Additionally, you should make sure you've checked
 969          * ContentHandler::canBeUsedOn() first.
 970          *
 971          * @since 1.28
 972          * @param string $model CONTENT_MODEL_XXX constant
 973          */
 974         public function setContentModel( $model ) {
 975                 $this->mContentModel = $model;
 976                 $this->mForcedContentModel = true;
 977         }
 978
 979         /**
 980          * Get the namespace text
 981          *
 982          * @return string|false Namespace text
 983          */
 984         public function getNsText() {
 985                 if ( $this->isExternal() ) {
 986                         // This probably shouldn't even happen,
 987                         // but for interwiki transclusion it sometimes does.
 988                         // Use the canonical namespaces if possible to try to
 989                         // resolve a foreign namespace.
 990                         if ( MWNamespace::exists( $this->mNamespace ) ) {
 991                                 return MWNamespace::getCanonicalName( $this->mNamespace );
 992                         }
 993                 }
 994
 995                 try {
 996                         $formatter = self::getTitleFormatter();
 997                         return $formatter->getNamespaceName( $this->mNamespace, $this->mDbkeyform );
 998                 } catch ( InvalidArgumentException $ex ) {
 999                         wfDebug( __METHOD__ . ': ' . $ex->getMessage() . "\n" );
1000                         return false;
1001                 }
1002         }
1003
1004         /**
1005          * Get the namespace text of the subject (rather than talk) page
1006          *
1007          * @return string Namespace text
1008          */
1009         public function getSubjectNsText() {
1010                 global $wgContLang;
1011                 return $wgContLang->getNsText( MWNamespace::getSubject( $this->mNamespace ) );
1012         }
1013
1014         /**
1015          * Get the namespace text of the talk page
1016          *
1017          * @return string Namespace text
1018          */
1019         public function getTalkNsText() {
1020                 global $wgContLang;
1021                 return $wgContLang->getNsText( MWNamespace::getTalk( $this->mNamespace ) );
1022         }
1023
1024         /**
1025          * Can this title have a corresponding talk page?
1026          *
1027          * @deprecated since 1.30, use canHaveTalkPage() instead.
1028          *
1029          * @return bool True if this title either is a talk page or can have a talk page associated.
1030          */
1031         public function canTalk() {
1032                 return $this->canHaveTalkPage();
1033         }
1034
1035         /**
1036          * Can this title have a corresponding talk page?
1037          *
1038          * @see MWNamespace::hasTalkNamespace
1039          *
1040          * @return bool True if this title either is a talk page or can have a talk page associated.
1041          */
1042         public function canHaveTalkPage() {
1043                 return MWNamespace::hasTalkNamespace( $this->mNamespace );
1044         }
1045
1046         /**
1047          * Is this in a namespace that allows actual pages?
1048          *
1049          * @return bool
1050          */
1051         public function canExist() {
1052                 return $this->mNamespace >= NS_MAIN;
1053         }
1054
1055         /**
1056          * Can this title be added to a user's watchlist?
1057          *
1058          * @return bool
1059          */
1060         public function isWatchable() {
1061                 return !$this->isExternal() && MWNamespace::isWatchable( $this->getNamespace() );
1062         }
1063
1064         /**
1065          * Returns true if this is a special page.
1066          *
1067          * @return bool
1068          */
1069         public function isSpecialPage() {
1070                 return $this->getNamespace() == NS_SPECIAL;
1071         }
1072
1073         /**
1074          * Returns true if this title resolves to the named special page
1075          *
1076          * @param string $name The special page name
1077          * @return bool
1078          */
1079         public function isSpecial( $name ) {
1080                 if ( $this->isSpecialPage() ) {
1081                         list( $thisName, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $this->getDBkey() );
1082                         if ( $name == $thisName ) {
1083                                 return true;
1084                         }
1085                 }
1086                 return false;
1087         }
1088
1089         /**
1090          * If the Title refers to a special page alias which is not the local default, resolve
1091          * the alias, and localise the name as necessary.  Otherwise, return $this
1092          *
1093          * @return Title
1094          */
1095         public function fixSpecialName() {
1096                 if ( $this->isSpecialPage() ) {
1097                         list( $canonicalName, $par ) = SpecialPageFactory::resolveAlias( $this->mDbkeyform );
1098                         if ( $canonicalName ) {
1099                                 $localName = SpecialPageFactory::getLocalNameFor( $canonicalName, $par );
1100                                 if ( $localName != $this->mDbkeyform ) {
1101                                         return self::makeTitle( NS_SPECIAL, $localName );
1102                                 }
1103                         }
1104                 }
1105                 return $this;
1106         }
1107
1108         /**
1109          * Returns true if the title is inside the specified namespace.
1110          *
1111          * Please make use of this instead of comparing to getNamespace()
1112          * This function is much more resistant to changes we may make
1113          * to namespaces than code that makes direct comparisons.
1114          * @param int $ns The namespace
1115          * @return bool
1116          * @since 1.19
1117          */
1118         public function inNamespace( $ns ) {
1119                 return MWNamespace::equals( $this->getNamespace(), $ns );
1120         }
1121
1122         /**
1123          * Returns true if the title is inside one of the specified namespaces.
1124          *
1125          * @param int|int[] $namespaces,... The namespaces to check for
1126          * @return bool
1127          * @since 1.19
1128          */
1129         public function inNamespaces( /* ... */ ) {
1130                 $namespaces = func_get_args();
1131                 if ( count( $namespaces ) > 0 && is_array( $namespaces[0] ) ) {
1132                         $namespaces = $namespaces[0];
1133                 }
1134
1135                 foreach ( $namespaces as $ns ) {
1136                         if ( $this->inNamespace( $ns ) ) {
1137                                 return true;
1138                         }
1139                 }
1140
1141                 return false;
1142         }
1143
1144         /**
1145          * Returns true if the title has the same subject namespace as the
1146          * namespace specified.
1147          * For example this method will take NS_USER and return true if namespace
1148          * is either NS_USER or NS_USER_TALK since both of them have NS_USER
1149          * as their subject namespace.
1150          *
1151          * This is MUCH simpler than individually testing for equivalence
1152          * against both NS_USER and NS_USER_TALK, and is also forward compatible.
1153          * @since 1.19
1154          * @param int $ns
1155          * @return bool
1156          */
1157         public function hasSubjectNamespace( $ns ) {
1158                 return MWNamespace::subjectEquals( $this->getNamespace(), $ns );
1159         }
1160
1161         /**
1162          * Is this Title in a namespace which contains content?
1163          * In other words, is this a content page, for the purposes of calculating
1164          * statistics, etc?
1165          *
1166          * @return bool
1167          */
1168         public function isContentPage() {
1169                 return MWNamespace::isContent( $this->getNamespace() );
1170         }
1171
1172         /**
1173          * Would anybody with sufficient privileges be able to move this page?
1174          * Some pages just aren't movable.
1175          *
1176          * @return bool
1177          */
1178         public function isMovable() {
1179                 if ( !MWNamespace::isMovable( $this->getNamespace() ) || $this->isExternal() ) {
1180                         // Interwiki title or immovable namespace. Hooks don't get to override here
1181                         return false;
1182                 }
1183
1184                 $result = true;
1185                 Hooks::run( 'TitleIsMovable', [ $this, &$result ] );
1186                 return $result;
1187         }
1188
1189         /**
1190          * Is this the mainpage?
1191          * @note Title::newFromText seems to be sufficiently optimized by the title
1192          * cache that we don't need to over-optimize by doing direct comparisons and
1193          * accidentally creating new bugs where $title->equals( Title::newFromText() )
1194          * ends up reporting something differently than $title->isMainPage();
1195          *
1196          * @since 1.18
1197          * @return bool
1198          */
1199         public function isMainPage() {
1200                 return $this->equals( self::newMainPage() );
1201         }
1202
1203         /**
1204          * Is this a subpage?
1205          *
1206          * @return bool
1207          */
1208         public function isSubpage() {
1209                 return MWNamespace::hasSubpages( $this->mNamespace )
1210                         ? strpos( $this->getText(), '/' ) !== false
1211                         : false;
1212         }
1213
1214         /**
1215          * Is this a conversion table for the LanguageConverter?
1216          *
1217          * @return bool
1218          */
1219         public function isConversionTable() {
1220                 // @todo ConversionTable should become a separate content model.
1221
1222                 return $this->getNamespace() == NS_MEDIAWIKI &&
1223                         strpos( $this->getText(), 'Conversiontable/' ) === 0;
1224         }
1225
1226         /**
1227          * Does that page contain wikitext, or it is JS, CSS or whatever?
1228          *
1229          * @return bool
1230          */
1231         public function isWikitextPage() {
1232                 return $this->hasContentModel( CONTENT_MODEL_WIKITEXT );
1233         }
1234
1235         /**
1236          * Could this page contain custom CSS or JavaScript for the global UI.
1237          * This is generally true for pages in the MediaWiki namespace having CONTENT_MODEL_CSS
1238          * or CONTENT_MODEL_JAVASCRIPT.
1239          *
1240          * This method does *not* return true for per-user JS/CSS. Use isCssJsSubpage()
1241          * for that!
1242          *
1243          * Note that this method should not return true for pages that contain and
1244          * show "inactive" CSS or JS.
1245          *
1246          * @return bool
1247          * @todo FIXME: Rename to isSiteConfigPage() and remove deprecated hook
1248          */
1249         public function isCssOrJsPage() {
1250                 $isCssOrJsPage = NS_MEDIAWIKI == $this->mNamespace
1251                         && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1252                                 || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1253
1254                 return $isCssOrJsPage;
1255         }
1256
1257         /**
1258          * Is this a .css or .js subpage of a user page?
1259          * @return bool
1260          * @todo FIXME: Rename to isUserConfigPage()
1261          */
1262         public function isCssJsSubpage() {
1263                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1264                                 && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1265                                         || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) ) );
1266         }
1267
1268         /**
1269          * Trim down a .css or .js subpage title to get the corresponding skin name
1270          *
1271          * @return string Containing skin name from .css or .js subpage title
1272          */
1273         public function getSkinFromCssJsSubpage() {
1274                 $subpage = explode( '/', $this->mTextform );
1275                 $subpage = $subpage[count( $subpage ) - 1];
1276                 $lastdot = strrpos( $subpage, '.' );
1277                 if ( $lastdot === false ) {
1278                         return $subpage; # Never happens: only called for names ending in '.css' or '.js'
1279                 }
1280                 return substr( $subpage, 0, $lastdot );
1281         }
1282
1283         /**
1284          * Is this a .css subpage of a user page?
1285          *
1286          * @return bool
1287          */
1288         public function isCssSubpage() {
1289                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1290                         && $this->hasContentModel( CONTENT_MODEL_CSS ) );
1291         }
1292
1293         /**
1294          * Is this a .js subpage of a user page?
1295          *
1296          * @return bool
1297          */
1298         public function isJsSubpage() {
1299                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1300                         && $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1301         }
1302
1303         /**
1304          * Is this a talk page of some sort?
1305          *
1306          * @return bool
1307          */
1308         public function isTalkPage() {
1309                 return MWNamespace::isTalk( $this->getNamespace() );
1310         }
1311
1312         /**
1313          * Get a Title object associated with the talk page of this article
1314          *
1315          * @return Title The object for the talk page
1316          */
1317         public function getTalkPage() {
1318                 return self::makeTitle( MWNamespace::getTalk( $this->getNamespace() ), $this->getDBkey() );
1319         }
1320
1321         /**
1322          * Get a Title object associated with the talk page of this article,
1323          * if such a talk page can exist.
1324          *
1325          * @since 1.30
1326          *
1327          * @return Title|null The object for the talk page,
1328          *         or null if no associated talk page can exist, according to canHaveTalkPage().
1329          */
1330         public function getTalkPageIfDefined() {
1331                 if ( !$this->canHaveTalkPage() ) {
1332                         return null;
1333                 }
1334
1335                 return $this->getTalkPage();
1336         }
1337
1338         /**
1339          * Get a title object associated with the subject page of this
1340          * talk page
1341          *
1342          * @return Title The object for the subject page
1343          */
1344         public function getSubjectPage() {
1345                 // Is this the same title?
1346                 $subjectNS = MWNamespace::getSubject( $this->getNamespace() );
1347                 if ( $this->getNamespace() == $subjectNS ) {
1348                         return $this;
1349                 }
1350                 return self::makeTitle( $subjectNS, $this->getDBkey() );
1351         }
1352
1353         /**
1354          * Get the other title for this page, if this is a subject page
1355          * get the talk page, if it is a subject page get the talk page
1356          *
1357          * @since 1.25
1358          * @throws MWException If the page doesn't have an other page
1359          * @return Title
1360          */
1361         public function getOtherPage() {
1362                 if ( $this->isSpecialPage() ) {
1363                         throw new MWException( 'Special pages cannot have other pages' );
1364                 }
1365                 if ( $this->isTalkPage() ) {
1366                         return $this->getSubjectPage();
1367                 } else {
1368                         if ( !$this->canHaveTalkPage() ) {
1369                                 throw new MWException( "{$this->getPrefixedText()} does not have an other page" );
1370                         }
1371                         return $this->getTalkPage();
1372                 }
1373         }
1374
1375         /**
1376          * Get the default namespace index, for when there is no namespace
1377          *
1378          * @return int Default namespace index
1379          */
1380         public function getDefaultNamespace() {
1381                 return $this->mDefaultNamespace;
1382         }
1383
1384         /**
1385          * Get the Title fragment (i.e.\ the bit after the #) in text form
1386          *
1387          * Use Title::hasFragment to check for a fragment
1388          *
1389          * @return string Title fragment
1390          */
1391         public function getFragment() {
1392                 return $this->mFragment;
1393         }
1394
1395         /**
1396          * Check if a Title fragment is set
1397          *
1398          * @return bool
1399          * @since 1.23
1400          */
1401         public function hasFragment() {
1402                 return $this->mFragment !== '';
1403         }
1404
1405         /**
1406          * Get the fragment in URL form, including the "#" character if there is one
1407          *
1408          * @return string Fragment in URL form
1409          */
1410         public function getFragmentForURL() {
1411                 if ( !$this->hasFragment() ) {
1412                         return '';
1413                 } elseif ( $this->isExternal() && !$this->getTransWikiID() ) {
1414                         return '#' . Sanitizer::escapeIdForExternalInterwiki( $this->getFragment() );
1415                 }
1416                 return '#' . Sanitizer::escapeIdForLink( $this->getFragment() );
1417         }
1418
1419         /**
1420          * Set the fragment for this title. Removes the first character from the
1421          * specified fragment before setting, so it assumes you're passing it with
1422          * an initial "#".
1423          *
1424          * Deprecated for public use, use Title::makeTitle() with fragment parameter,
1425          * or Title::createFragmentTarget().
1426          * Still in active use privately.
1427          *
1428          * @private
1429          * @param string $fragment Text
1430          */
1431         public function setFragment( $fragment ) {
1432                 $this->mFragment = strtr( substr( $fragment, 1 ), '_', ' ' );
1433         }
1434
1435         /**
1436          * Creates a new Title for a different fragment of the same page.
1437          *
1438          * @since 1.27
1439          * @param string $fragment
1440          * @return Title
1441          */
1442         public function createFragmentTarget( $fragment ) {
1443                 return self::makeTitle(
1444                         $this->getNamespace(),
1445                         $this->getText(),
1446                         $fragment,
1447                         $this->getInterwiki()
1448                 );
1449         }
1450
1451         /**
1452          * Prefix some arbitrary text with the namespace or interwiki prefix
1453          * of this object
1454          *
1455          * @param string $name The text
1456          * @return string The prefixed text
1457          */
1458         private function prefix( $name ) {
1459                 global $wgContLang;
1460
1461                 $p = '';
1462                 if ( $this->isExternal() ) {
1463                         $p = $this->mInterwiki . ':';
1464                 }
1465
1466                 if ( 0 != $this->mNamespace ) {
1467                         $nsText = $this->getNsText();
1468
1469                         if ( $nsText === false ) {
1470                                 // See T165149. Awkward, but better than erroneously linking to the main namespace.
1471                                 $nsText = $wgContLang->getNsText( NS_SPECIAL ) . ":Badtitle/NS{$this->mNamespace}";
1472                         }
1473
1474                         $p .= $nsText . ':';
1475                 }
1476                 return $p . $name;
1477         }
1478
1479         /**
1480          * Get the prefixed database key form
1481          *
1482          * @return string The prefixed title, with underscores and
1483          *  any interwiki and namespace prefixes
1484          */
1485         public function getPrefixedDBkey() {
1486                 $s = $this->prefix( $this->mDbkeyform );
1487                 $s = strtr( $s, ' ', '_' );
1488                 return $s;
1489         }
1490
1491         /**
1492          * Get the prefixed title with spaces.
1493          * This is the form usually used for display
1494          *
1495          * @return string The prefixed title, with spaces
1496          */
1497         public function getPrefixedText() {
1498                 if ( $this->mPrefixedText === null ) {
1499                         $s = $this->prefix( $this->mTextform );
1500                         $s = strtr( $s, '_', ' ' );
1501                         $this->mPrefixedText = $s;
1502                 }
1503                 return $this->mPrefixedText;
1504         }
1505
1506         /**
1507          * Return a string representation of this title
1508          *
1509          * @return string Representation of this title
1510          */
1511         public function __toString() {
1512                 return $this->getPrefixedText();
1513         }
1514
1515         /**
1516          * Get the prefixed title with spaces, plus any fragment
1517          * (part beginning with '#')
1518          *
1519          * @return string The prefixed title, with spaces and the fragment, including '#'
1520          */
1521         public function getFullText() {
1522                 $text = $this->getPrefixedText();
1523                 if ( $this->hasFragment() ) {
1524                         $text .= '#' . $this->getFragment();
1525                 }
1526                 return $text;
1527         }
1528
1529         /**
1530          * Get the root page name text without a namespace, i.e. the leftmost part before any slashes
1531          *
1532          * @par Example:
1533          * @code
1534          * Title::newFromText('User:Foo/Bar/Baz')->getRootText();
1535          * # returns: 'Foo'
1536          * @endcode
1537          *
1538          * @return string Root name
1539          * @since 1.20
1540          */
1541         public function getRootText() {
1542                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1543                         return $this->getText();
1544                 }
1545
1546                 return strtok( $this->getText(), '/' );
1547         }
1548
1549         /**
1550          * Get the root page name title, i.e. the leftmost part before any slashes
1551          *
1552          * @par Example:
1553          * @code
1554          * Title::newFromText('User:Foo/Bar/Baz')->getRootTitle();
1555          * # returns: Title{User:Foo}
1556          * @endcode
1557          *
1558          * @return Title Root title
1559          * @since 1.20
1560          */
1561         public function getRootTitle() {
1562                 return self::makeTitle( $this->getNamespace(), $this->getRootText() );
1563         }
1564
1565         /**
1566          * Get the base page name without a namespace, i.e. the part before the subpage name
1567          *
1568          * @par Example:
1569          * @code
1570          * Title::newFromText('User:Foo/Bar/Baz')->getBaseText();
1571          * # returns: 'Foo/Bar'
1572          * @endcode
1573          *
1574          * @return string Base name
1575          */
1576         public function getBaseText() {
1577                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1578                         return $this->getText();
1579                 }
1580
1581                 $parts = explode( '/', $this->getText() );
1582                 # Don't discard the real title if there's no subpage involved
1583                 if ( count( $parts ) > 1 ) {
1584                         unset( $parts[count( $parts ) - 1] );
1585                 }
1586                 return implode( '/', $parts );
1587         }
1588
1589         /**
1590          * Get the base page name title, i.e. the part before the subpage name
1591          *
1592          * @par Example:
1593          * @code
1594          * Title::newFromText('User:Foo/Bar/Baz')->getBaseTitle();
1595          * # returns: Title{User:Foo/Bar}
1596          * @endcode
1597          *
1598          * @return Title Base title
1599          * @since 1.20
1600          */
1601         public function getBaseTitle() {
1602                 return self::makeTitle( $this->getNamespace(), $this->getBaseText() );
1603         }
1604
1605         /**
1606          * Get the lowest-level subpage name, i.e. the rightmost part after any slashes
1607          *
1608          * @par Example:
1609          * @code
1610          * Title::newFromText('User:Foo/Bar/Baz')->getSubpageText();
1611          * # returns: "Baz"
1612          * @endcode
1613          *
1614          * @return string Subpage name
1615          */
1616         public function getSubpageText() {
1617                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1618                         return $this->mTextform;
1619                 }
1620                 $parts = explode( '/', $this->mTextform );
1621                 return $parts[count( $parts ) - 1];
1622         }
1623
1624         /**
1625          * Get the title for a subpage of the current page
1626          *
1627          * @par Example:
1628          * @code
1629          * Title::newFromText('User:Foo/Bar/Baz')->getSubpage("Asdf");
1630          * # returns: Title{User:Foo/Bar/Baz/Asdf}
1631          * @endcode
1632          *
1633          * @param string $text The subpage name to add to the title
1634          * @return Title Subpage title
1635          * @since 1.20
1636          */
1637         public function getSubpage( $text ) {
1638                 return self::makeTitleSafe( $this->getNamespace(), $this->getText() . '/' . $text );
1639         }
1640
1641         /**
1642          * Get a URL-encoded form of the subpage text
1643          *
1644          * @return string URL-encoded subpage name
1645          */
1646         public function getSubpageUrlForm() {
1647                 $text = $this->getSubpageText();
1648                 $text = wfUrlencode( strtr( $text, ' ', '_' ) );
1649                 return $text;
1650         }
1651
1652         /**
1653          * Get a URL-encoded title (not an actual URL) including interwiki
1654          *
1655          * @return string The URL-encoded form
1656          */
1657         public function getPrefixedURL() {
1658                 $s = $this->prefix( $this->mDbkeyform );
1659                 $s = wfUrlencode( strtr( $s, ' ', '_' ) );
1660                 return $s;
1661         }
1662
1663         /**
1664          * Helper to fix up the get{Canonical,Full,Link,Local,Internal}URL args
1665          * get{Canonical,Full,Link,Local,Internal}URL methods accepted an optional
1666          * second argument named variant. This was deprecated in favor
1667          * of passing an array of option with a "variant" key
1668          * Once $query2 is removed for good, this helper can be dropped
1669          * and the wfArrayToCgi moved to getLocalURL();
1670          *
1671          * @since 1.19 (r105919)
1672          * @param array|string $query
1673          * @param string|string[]|bool $query2
1674          * @return string
1675          */
1676         private static function fixUrlQueryArgs( $query, $query2 = false ) {
1677                 if ( $query2 !== false ) {
1678                         wfDeprecated( "Title::get{Canonical,Full,Link,Local,Internal}URL " .
1679                                 "method called with a second parameter is deprecated. Add your " .
1680                                 "parameter to an array passed as the first parameter.", "1.19" );
1681                 }
1682                 if ( is_array( $query ) ) {
1683                         $query = wfArrayToCgi( $query );
1684                 }
1685                 if ( $query2 ) {
1686                         if ( is_string( $query2 ) ) {
1687                                 // $query2 is a string, we will consider this to be
1688                                 // a deprecated $variant argument and add it to the query
1689                                 $query2 = wfArrayToCgi( [ 'variant' => $query2 ] );
1690                         } else {
1691                                 $query2 = wfArrayToCgi( $query2 );
1692                         }
1693                         // If we have $query content add a & to it first
1694                         if ( $query ) {
1695                                 $query .= '&';
1696                         }
1697                         // Now append the queries together
1698                         $query .= $query2;
1699                 }
1700                 return $query;
1701         }
1702
1703         /**
1704          * Get a real URL referring to this title, with interwiki link and
1705          * fragment
1706          *
1707          * @see self::getLocalURL for the arguments.
1708          * @see wfExpandUrl
1709          * @param string|string[] $query
1710          * @param string|string[]|bool $query2
1711          * @param string $proto Protocol type to use in URL
1712          * @return string The URL
1713          */
1714         public function getFullURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1715                 $query = self::fixUrlQueryArgs( $query, $query2 );
1716
1717                 # Hand off all the decisions on urls to getLocalURL
1718                 $url = $this->getLocalURL( $query );
1719
1720                 # Expand the url to make it a full url. Note that getLocalURL has the
1721                 # potential to output full urls for a variety of reasons, so we use
1722                 # wfExpandUrl instead of simply prepending $wgServer
1723                 $url = wfExpandUrl( $url, $proto );
1724
1725                 # Finally, add the fragment.
1726                 $url .= $this->getFragmentForURL();
1727                 // Avoid PHP 7.1 warning from passing $this by reference
1728                 $titleRef = $this;
1729                 Hooks::run( 'GetFullURL', [ &$titleRef, &$url, $query ] );
1730                 return $url;
1731         }
1732
1733         /**
1734          * Get a url appropriate for making redirects based on an untrusted url arg
1735          *
1736          * This is basically the same as getFullUrl(), but in the case of external
1737          * interwikis, we send the user to a landing page, to prevent possible
1738          * phishing attacks and the like.
1739          *
1740          * @note Uses current protocol by default, since technically relative urls
1741          *   aren't allowed in redirects per HTTP spec, so this is not suitable for
1742          *   places where the url gets cached, as might pollute between
1743          *   https and non-https users.
1744          * @see self::getLocalURL for the arguments.
1745          * @param array|string $query
1746          * @param string $proto Protocol type to use in URL
1747          * @return String. A url suitable to use in an HTTP location header.
1748          */
1749         public function getFullUrlForRedirect( $query = '', $proto = PROTO_CURRENT ) {
1750                 $target = $this;
1751                 if ( $this->isExternal() ) {
1752                         $target = SpecialPage::getTitleFor(
1753                                 'GoToInterwiki',
1754                                 $this->getPrefixedDBKey()
1755                         );
1756                 }
1757                 return $target->getFullUrl( $query, false, $proto );
1758         }
1759
1760         /**
1761          * Get a URL with no fragment or server name (relative URL) from a Title object.
1762          * If this page is generated with action=render, however,
1763          * $wgServer is prepended to make an absolute URL.
1764          *
1765          * @see self::getFullURL to always get an absolute URL.
1766          * @see self::getLinkURL to always get a URL that's the simplest URL that will be
1767          *  valid to link, locally, to the current Title.
1768          * @see self::newFromText to produce a Title object.
1769          *
1770          * @param string|string[] $query An optional query string,
1771          *   not used for interwiki links. Can be specified as an associative array as well,
1772          *   e.g., array( 'action' => 'edit' ) (keys and values will be URL-escaped).
1773          *   Some query patterns will trigger various shorturl path replacements.
1774          * @param string|string[]|bool $query2 An optional secondary query array. This one MUST
1775          *   be an array. If a string is passed it will be interpreted as a deprecated
1776          *   variant argument and urlencoded into a variant= argument.
1777          *   This second query argument will be added to the $query
1778          *   The second parameter is deprecated since 1.19. Pass it as a key,value
1779          *   pair in the first parameter array instead.
1780          *
1781          * @return string String of the URL.
1782          */
1783         public function getLocalURL( $query = '', $query2 = false ) {
1784                 global $wgArticlePath, $wgScript, $wgServer, $wgRequest;
1785
1786                 $query = self::fixUrlQueryArgs( $query, $query2 );
1787
1788                 $interwiki = self::getInterwikiLookup()->fetch( $this->mInterwiki );
1789                 if ( $interwiki ) {
1790                         $namespace = $this->getNsText();
1791                         if ( $namespace != '' ) {
1792                                 # Can this actually happen? Interwikis shouldn't be parsed.
1793                                 # Yes! It can in interwiki transclusion. But... it probably shouldn't.
1794                                 $namespace .= ':';
1795                         }
1796                         $url = $interwiki->getURL( $namespace . $this->getDBkey() );
1797                         $url = wfAppendQuery( $url, $query );
1798                 } else {
1799                         $dbkey = wfUrlencode( $this->getPrefixedDBkey() );
1800                         if ( $query == '' ) {
1801                                 $url = str_replace( '$1', $dbkey, $wgArticlePath );
1802                                 // Avoid PHP 7.1 warning from passing $this by reference
1803                                 $titleRef = $this;
1804                                 Hooks::run( 'GetLocalURL::Article', [ &$titleRef, &$url ] );
1805                         } else {
1806                                 global $wgVariantArticlePath, $wgActionPaths, $wgContLang;
1807                                 $url = false;
1808                                 $matches = [];
1809
1810                                 if ( !empty( $wgActionPaths )
1811                                         && preg_match( '/^(.*&|)action=([^&]*)(&(.*)|)$/', $query, $matches )
1812                                 ) {
1813                                         $action = urldecode( $matches[2] );
1814                                         if ( isset( $wgActionPaths[$action] ) ) {
1815                                                 $query = $matches[1];
1816                                                 if ( isset( $matches[4] ) ) {
1817                                                         $query .= $matches[4];
1818                                                 }
1819                                                 $url = str_replace( '$1', $dbkey, $wgActionPaths[$action] );
1820                                                 if ( $query != '' ) {
1821                                                         $url = wfAppendQuery( $url, $query );
1822                                                 }
1823                                         }
1824                                 }
1825
1826                                 if ( $url === false
1827                                         && $wgVariantArticlePath
1828                                         && preg_match( '/^variant=([^&]*)$/', $query, $matches )
1829                                         && $this->getPageLanguage()->equals( $wgContLang )
1830                                         && $this->getPageLanguage()->hasVariants()
1831                                 ) {
1832                                         $variant = urldecode( $matches[1] );
1833                                         if ( $this->getPageLanguage()->hasVariant( $variant ) ) {
1834                                                 // Only do the variant replacement if the given variant is a valid
1835                                                 // variant for the page's language.
1836                                                 $url = str_replace( '$2', urlencode( $variant ), $wgVariantArticlePath );
1837                                                 $url = str_replace( '$1', $dbkey, $url );
1838                                         }
1839                                 }
1840
1841                                 if ( $url === false ) {
1842                                         if ( $query == '-' ) {
1843                                                 $query = '';
1844                                         }
1845                                         $url = "{$wgScript}?title={$dbkey}&{$query}";
1846                                 }
1847                         }
1848                         // Avoid PHP 7.1 warning from passing $this by reference
1849                         $titleRef = $this;
1850                         Hooks::run( 'GetLocalURL::Internal', [ &$titleRef, &$url, $query ] );
1851
1852                         // @todo FIXME: This causes breakage in various places when we
1853                         // actually expected a local URL and end up with dupe prefixes.
1854                         if ( $wgRequest->getVal( 'action' ) == 'render' ) {
1855                                 $url = $wgServer . $url;
1856                         }
1857                 }
1858                 // Avoid PHP 7.1 warning from passing $this by reference
1859                 $titleRef = $this;
1860                 Hooks::run( 'GetLocalURL', [ &$titleRef, &$url, $query ] );
1861                 return $url;
1862         }
1863
1864         /**
1865          * Get a URL that's the simplest URL that will be valid to link, locally,
1866          * to the current Title.  It includes the fragment, but does not include
1867          * the server unless action=render is used (or the link is external).  If
1868          * there's a fragment but the prefixed text is empty, we just return a link
1869          * to the fragment.
1870          *
1871          * The result obviously should not be URL-escaped, but does need to be
1872          * HTML-escaped if it's being output in HTML.
1873          *
1874          * @param string|string[] $query
1875          * @param bool $query2
1876          * @param string|int|bool $proto A PROTO_* constant on how the URL should be expanded,
1877          *                               or false (default) for no expansion
1878          * @see self::getLocalURL for the arguments.
1879          * @return string The URL
1880          */
1881         public function getLinkURL( $query = '', $query2 = false, $proto = false ) {
1882                 if ( $this->isExternal() || $proto !== false ) {
1883                         $ret = $this->getFullURL( $query, $query2, $proto );
1884                 } elseif ( $this->getPrefixedText() === '' && $this->hasFragment() ) {
1885                         $ret = $this->getFragmentForURL();
1886                 } else {
1887                         $ret = $this->getLocalURL( $query, $query2 ) . $this->getFragmentForURL();
1888                 }
1889                 return $ret;
1890         }
1891
1892         /**
1893          * Get the URL form for an internal link.
1894          * - Used in various CDN-related code, in case we have a different
1895          * internal hostname for the server from the exposed one.
1896          *
1897          * This uses $wgInternalServer to qualify the path, or $wgServer
1898          * if $wgInternalServer is not set. If the server variable used is
1899          * protocol-relative, the URL will be expanded to http://
1900          *
1901          * @see self::getLocalURL for the arguments.
1902          * @param string $query
1903          * @param string|bool $query2
1904          * @return string The URL
1905          */
1906         public function getInternalURL( $query = '', $query2 = false ) {
1907                 global $wgInternalServer, $wgServer;
1908                 $query = self::fixUrlQueryArgs( $query, $query2 );
1909                 $server = $wgInternalServer !== false ? $wgInternalServer : $wgServer;
1910                 $url = wfExpandUrl( $server . $this->getLocalURL( $query ), PROTO_HTTP );
1911                 // Avoid PHP 7.1 warning from passing $this by reference
1912                 $titleRef = $this;
1913                 Hooks::run( 'GetInternalURL', [ &$titleRef, &$url, $query ] );
1914                 return $url;
1915         }
1916
1917         /**
1918          * Get the URL for a canonical link, for use in things like IRC and
1919          * e-mail notifications. Uses $wgCanonicalServer and the
1920          * GetCanonicalURL hook.
1921          *
1922          * NOTE: Unlike getInternalURL(), the canonical URL includes the fragment
1923          *
1924          * @see self::getLocalURL for the arguments.
1925          * @return string The URL
1926          * @since 1.18
1927          */
1928         public function getCanonicalURL( $query = '', $query2 = false ) {
1929                 $query = self::fixUrlQueryArgs( $query, $query2 );
1930                 $url = wfExpandUrl( $this->getLocalURL( $query ) . $this->getFragmentForURL(), PROTO_CANONICAL );
1931                 // Avoid PHP 7.1 warning from passing $this by reference
1932                 $titleRef = $this;
1933                 Hooks::run( 'GetCanonicalURL', [ &$titleRef, &$url, $query ] );
1934                 return $url;
1935         }
1936
1937         /**
1938          * Get the edit URL for this Title
1939          *
1940          * @return string The URL, or a null string if this is an interwiki link
1941          */
1942         public function getEditURL() {
1943                 if ( $this->isExternal() ) {
1944                         return '';
1945                 }
1946                 $s = $this->getLocalURL( 'action=edit' );
1947
1948                 return $s;
1949         }
1950
1951         /**
1952          * Can $user perform $action on this page?
1953          * This skips potentially expensive cascading permission checks
1954          * as well as avoids expensive error formatting
1955          *
1956          * Suitable for use for nonessential UI controls in common cases, but
1957          * _not_ for functional access control.
1958          *
1959          * May provide false positives, but should never provide a false negative.
1960          *
1961          * @param string $action Action that permission needs to be checked for
1962          * @param User $user User to check (since 1.19); $wgUser will be used if not provided.
1963          * @return bool
1964          */
1965         public function quickUserCan( $action, $user = null ) {
1966                 return $this->userCan( $action, $user, false );
1967         }
1968
1969         /**
1970          * Can $user perform $action on this page?
1971          *
1972          * @param string $action Action that permission needs to be checked for
1973          * @param User $user User to check (since 1.19); $wgUser will be used if not
1974          *   provided.
1975          * @param string $rigor Same format as Title::getUserPermissionsErrors()
1976          * @return bool
1977          */
1978         public function userCan( $action, $user = null, $rigor = 'secure' ) {
1979                 if ( !$user instanceof User ) {
1980                         global $wgUser;
1981                         $user = $wgUser;
1982                 }
1983
1984                 return !count( $this->getUserPermissionsErrorsInternal( $action, $user, $rigor, true ) );
1985         }
1986
1987         /**
1988          * Can $user perform $action on this page?
1989          *
1990          * @todo FIXME: This *does not* check throttles (User::pingLimiter()).
1991          *
1992          * @param string $action Action that permission needs to be checked for
1993          * @param User $user User to check
1994          * @param string $rigor One of (quick,full,secure)
1995          *   - quick  : does cheap permission checks from replica DBs (usable for GUI creation)
1996          *   - full   : does cheap and expensive checks possibly from a replica DB
1997          *   - secure : does cheap and expensive checks, using the master as needed
1998          * @param array $ignoreErrors Array of Strings Set this to a list of message keys
1999          *   whose corresponding errors may be ignored.
2000          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
2001          */
2002         public function getUserPermissionsErrors(
2003                 $action, $user, $rigor = 'secure', $ignoreErrors = []
2004         ) {
2005                 $errors = $this->getUserPermissionsErrorsInternal( $action, $user, $rigor );
2006
2007                 // Remove the errors being ignored.
2008                 foreach ( $errors as $index => $error ) {
2009                         $errKey = is_array( $error ) ? $error[0] : $error;
2010
2011                         if ( in_array( $errKey, $ignoreErrors ) ) {
2012                                 unset( $errors[$index] );
2013                         }
2014                         if ( $errKey instanceof MessageSpecifier && in_array( $errKey->getKey(), $ignoreErrors ) ) {
2015                                 unset( $errors[$index] );
2016                         }
2017                 }
2018
2019                 return $errors;
2020         }
2021
2022         /**
2023          * Permissions checks that fail most often, and which are easiest to test.
2024          *
2025          * @param string $action The action to check
2026          * @param User $user User to check
2027          * @param array $errors List of current errors
2028          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2029          * @param bool $short Short circuit on first error
2030          *
2031          * @return array List of errors
2032          */
2033         private function checkQuickPermissions( $action, $user, $errors, $rigor, $short ) {
2034                 if ( !Hooks::run( 'TitleQuickPermissions',
2035                         [ $this, $user, $action, &$errors, ( $rigor !== 'quick' ), $short ] )
2036                 ) {
2037                         return $errors;
2038                 }
2039
2040                 if ( $action == 'create' ) {
2041                         if (
2042                                 ( $this->isTalkPage() && !$user->isAllowed( 'createtalk' ) ) ||
2043                                 ( !$this->isTalkPage() && !$user->isAllowed( 'createpage' ) )
2044                         ) {
2045                                 $errors[] = $user->isAnon() ? [ 'nocreatetext' ] : [ 'nocreate-loggedin' ];
2046                         }
2047                 } elseif ( $action == 'move' ) {
2048                         if ( !$user->isAllowed( 'move-rootuserpages' )
2049                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
2050                                 // Show user page-specific message only if the user can move other pages
2051                                 $errors[] = [ 'cant-move-user-page' ];
2052                         }
2053
2054                         // Check if user is allowed to move files if it's a file
2055                         if ( $this->mNamespace == NS_FILE && !$user->isAllowed( 'movefile' ) ) {
2056                                 $errors[] = [ 'movenotallowedfile' ];
2057                         }
2058
2059                         // Check if user is allowed to move category pages if it's a category page
2060                         if ( $this->mNamespace == NS_CATEGORY && !$user->isAllowed( 'move-categorypages' ) ) {
2061                                 $errors[] = [ 'cant-move-category-page' ];
2062                         }
2063
2064                         if ( !$user->isAllowed( 'move' ) ) {
2065                                 // User can't move anything
2066                                 $userCanMove = User::groupHasPermission( 'user', 'move' );
2067                                 $autoconfirmedCanMove = User::groupHasPermission( 'autoconfirmed', 'move' );
2068                                 if ( $user->isAnon() && ( $userCanMove || $autoconfirmedCanMove ) ) {
2069                                         // custom message if logged-in users without any special rights can move
2070                                         $errors[] = [ 'movenologintext' ];
2071                                 } else {
2072                                         $errors[] = [ 'movenotallowed' ];
2073                                 }
2074                         }
2075                 } elseif ( $action == 'move-target' ) {
2076                         if ( !$user->isAllowed( 'move' ) ) {
2077                                 // User can't move anything
2078                                 $errors[] = [ 'movenotallowed' ];
2079                         } elseif ( !$user->isAllowed( 'move-rootuserpages' )
2080                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
2081                                 // Show user page-specific message only if the user can move other pages
2082                                 $errors[] = [ 'cant-move-to-user-page' ];
2083                         } elseif ( !$user->isAllowed( 'move-categorypages' )
2084                                         && $this->mNamespace == NS_CATEGORY ) {
2085                                 // Show category page-specific message only if the user can move other pages
2086                                 $errors[] = [ 'cant-move-to-category-page' ];
2087                         }
2088                 } elseif ( !$user->isAllowed( $action ) ) {
2089                         $errors[] = $this->missingPermissionError( $action, $short );
2090                 }
2091
2092                 return $errors;
2093         }
2094
2095         /**
2096          * Add the resulting error code to the errors array
2097          *
2098          * @param array $errors List of current errors
2099          * @param array $result Result of errors
2100          *
2101          * @return array List of errors
2102          */
2103         private function resultToError( $errors, $result ) {
2104                 if ( is_array( $result ) && count( $result ) && !is_array( $result[0] ) ) {
2105                         // A single array representing an error
2106                         $errors[] = $result;
2107                 } elseif ( is_array( $result ) && is_array( $result[0] ) ) {
2108                         // A nested array representing multiple errors
2109                         $errors = array_merge( $errors, $result );
2110                 } elseif ( $result !== '' && is_string( $result ) ) {
2111                         // A string representing a message-id
2112                         $errors[] = [ $result ];
2113                 } elseif ( $result instanceof MessageSpecifier ) {
2114                         // A message specifier representing an error
2115                         $errors[] = [ $result ];
2116                 } elseif ( $result === false ) {
2117                         // a generic "We don't want them to do that"
2118                         $errors[] = [ 'badaccess-group0' ];
2119                 }
2120                 return $errors;
2121         }
2122
2123         /**
2124          * Check various permission hooks
2125          *
2126          * @param string $action The action to check
2127          * @param User $user User to check
2128          * @param array $errors List of current errors
2129          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2130          * @param bool $short Short circuit on first error
2131          *
2132          * @return array List of errors
2133          */
2134         private function checkPermissionHooks( $action, $user, $errors, $rigor, $short ) {
2135                 // Use getUserPermissionsErrors instead
2136                 $result = '';
2137                 // Avoid PHP 7.1 warning from passing $this by reference
2138                 $titleRef = $this;
2139                 if ( !Hooks::run( 'userCan', [ &$titleRef, &$user, $action, &$result ] ) ) {
2140                         return $result ? [] : [ [ 'badaccess-group0' ] ];
2141                 }
2142                 // Check getUserPermissionsErrors hook
2143                 // Avoid PHP 7.1 warning from passing $this by reference
2144                 $titleRef = $this;
2145                 if ( !Hooks::run( 'getUserPermissionsErrors', [ &$titleRef, &$user, $action, &$result ] ) ) {
2146                         $errors = $this->resultToError( $errors, $result );
2147                 }
2148                 // Check getUserPermissionsErrorsExpensive hook
2149                 if (
2150                         $rigor !== 'quick'
2151                         && !( $short && count( $errors ) > 0 )
2152                         && !Hooks::run( 'getUserPermissionsErrorsExpensive', [ &$titleRef, &$user, $action, &$result ] )
2153                 ) {
2154                         $errors = $this->resultToError( $errors, $result );
2155                 }
2156
2157                 return $errors;
2158         }
2159
2160         /**
2161          * Check permissions on special pages & namespaces
2162          *
2163          * @param string $action The action to check
2164          * @param User $user User to check
2165          * @param array $errors List of current errors
2166          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2167          * @param bool $short Short circuit on first error
2168          *
2169          * @return array List of errors
2170          */
2171         private function checkSpecialsAndNSPermissions( $action, $user, $errors, $rigor, $short ) {
2172                 # Only 'createaccount' can be performed on special pages,
2173                 # which don't actually exist in the DB.
2174                 if ( $this->isSpecialPage() && $action !== 'createaccount' ) {
2175                         $errors[] = [ 'ns-specialprotected' ];
2176                 }
2177
2178                 # Check $wgNamespaceProtection for restricted namespaces
2179                 if ( $this->isNamespaceProtected( $user ) ) {
2180                         $ns = $this->mNamespace == NS_MAIN ?
2181                                 wfMessage( 'nstab-main' )->text() : $this->getNsText();
2182                         $errors[] = $this->mNamespace == NS_MEDIAWIKI ?
2183                                 [ 'protectedinterface', $action ] : [ 'namespaceprotected', $ns, $action ];
2184                 }
2185
2186                 return $errors;
2187         }
2188
2189         /**
2190          * Check CSS/JS sub-page permissions
2191          *
2192          * @param string $action The action to check
2193          * @param User $user User to check
2194          * @param array $errors List of current errors
2195          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2196          * @param bool $short Short circuit on first error
2197          *
2198          * @return array List of errors
2199          */
2200         private function checkCSSandJSPermissions( $action, $user, $errors, $rigor, $short ) {
2201                 # Protect css/js subpages of user pages
2202                 # XXX: this might be better using restrictions
2203                 if ( $action != 'patrol' ) {
2204                         if ( preg_match( '/^' . preg_quote( $user->getName(), '/' ) . '\//', $this->mTextform ) ) {
2205                                 if ( $this->isCssSubpage() && !$user->isAllowedAny( 'editmyusercss', 'editusercss' ) ) {
2206                                         $errors[] = [ 'mycustomcssprotected', $action ];
2207                                 } elseif ( $this->isJsSubpage() && !$user->isAllowedAny( 'editmyuserjs', 'edituserjs' ) ) {
2208                                         $errors[] = [ 'mycustomjsprotected', $action ];
2209                                 }
2210                         } else {
2211                                 if ( $this->isCssSubpage() && !$user->isAllowed( 'editusercss' ) ) {
2212                                         $errors[] = [ 'customcssprotected', $action ];
2213                                 } elseif ( $this->isJsSubpage() && !$user->isAllowed( 'edituserjs' ) ) {
2214                                         $errors[] = [ 'customjsprotected', $action ];
2215                                 }
2216                         }
2217                 }
2218
2219                 return $errors;
2220         }
2221
2222         /**
2223          * Check against page_restrictions table requirements on this
2224          * page. The user must possess all required rights for this
2225          * action.
2226          *
2227          * @param string $action The action to check
2228          * @param User $user User to check
2229          * @param array $errors List of current errors
2230          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2231          * @param bool $short Short circuit on first error
2232          *
2233          * @return array List of errors
2234          */
2235         private function checkPageRestrictions( $action, $user, $errors, $rigor, $short ) {
2236                 foreach ( $this->getRestrictions( $action ) as $right ) {
2237                         // Backwards compatibility, rewrite sysop -> editprotected
2238                         if ( $right == 'sysop' ) {
2239                                 $right = 'editprotected';
2240                         }
2241                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2242                         if ( $right == 'autoconfirmed' ) {
2243                                 $right = 'editsemiprotected';
2244                         }
2245                         if ( $right == '' ) {
2246                                 continue;
2247                         }
2248                         if ( !$user->isAllowed( $right ) ) {
2249                                 $errors[] = [ 'protectedpagetext', $right, $action ];
2250                         } elseif ( $this->mCascadeRestriction && !$user->isAllowed( 'protect' ) ) {
2251                                 $errors[] = [ 'protectedpagetext', 'protect', $action ];
2252                         }
2253                 }
2254
2255                 return $errors;
2256         }
2257
2258         /**
2259          * Check restrictions on cascading pages.
2260          *
2261          * @param string $action The action to check
2262          * @param User $user User to check
2263          * @param array $errors List of current errors
2264          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2265          * @param bool $short Short circuit on first error
2266          *
2267          * @return array List of errors
2268          */
2269         private function checkCascadingSourcesRestrictions( $action, $user, $errors, $rigor, $short ) {
2270                 if ( $rigor !== 'quick' && !$this->isCssJsSubpage() ) {
2271                         # We /could/ use the protection level on the source page, but it's
2272                         # fairly ugly as we have to establish a precedence hierarchy for pages
2273                         # included by multiple cascade-protected pages. So just restrict
2274                         # it to people with 'protect' permission, as they could remove the
2275                         # protection anyway.
2276                         list( $cascadingSources, $restrictions ) = $this->getCascadeProtectionSources();
2277                         # Cascading protection depends on more than this page...
2278                         # Several cascading protected pages may include this page...
2279                         # Check each cascading level
2280                         # This is only for protection restrictions, not for all actions
2281                         if ( isset( $restrictions[$action] ) ) {
2282                                 foreach ( $restrictions[$action] as $right ) {
2283                                         // Backwards compatibility, rewrite sysop -> editprotected
2284                                         if ( $right == 'sysop' ) {
2285                                                 $right = 'editprotected';
2286                                         }
2287                                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2288                                         if ( $right == 'autoconfirmed' ) {
2289                                                 $right = 'editsemiprotected';
2290                                         }
2291                                         if ( $right != '' && !$user->isAllowedAll( 'protect', $right ) ) {
2292                                                 $pages = '';
2293                                                 foreach ( $cascadingSources as $page ) {
2294                                                         $pages .= '* [[:' . $page->getPrefixedText() . "]]\n";
2295                                                 }
2296                                                 $errors[] = [ 'cascadeprotected', count( $cascadingSources ), $pages, $action ];
2297                                         }
2298                                 }
2299                         }
2300                 }
2301
2302                 return $errors;
2303         }
2304
2305         /**
2306          * Check action permissions not already checked in checkQuickPermissions
2307          *
2308          * @param string $action The action to check
2309          * @param User $user User to check
2310          * @param array $errors List of current errors
2311          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2312          * @param bool $short Short circuit on first error
2313          *
2314          * @return array List of errors
2315          */
2316         private function checkActionPermissions( $action, $user, $errors, $rigor, $short ) {
2317                 global $wgDeleteRevisionsLimit, $wgLang;
2318
2319                 if ( $action == 'protect' ) {
2320                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit', $user, $rigor, true ) ) ) {
2321                                 // If they can't edit, they shouldn't protect.
2322                                 $errors[] = [ 'protect-cantedit' ];
2323                         }
2324                 } elseif ( $action == 'create' ) {
2325                         $title_protection = $this->getTitleProtection();
2326                         if ( $title_protection ) {
2327                                 if ( $title_protection['permission'] == ''
2328                                         || !$user->isAllowed( $title_protection['permission'] )
2329                                 ) {
2330                                         $errors[] = [
2331                                                 'titleprotected',
2332                                                 User::whoIs( $title_protection['user'] ),
2333                                                 $title_protection['reason']
2334                                         ];
2335                                 }
2336                         }
2337                 } elseif ( $action == 'move' ) {
2338                         // Check for immobile pages
2339                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2340                                 // Specific message for this case
2341                                 $errors[] = [ 'immobile-source-namespace', $this->getNsText() ];
2342                         } elseif ( !$this->isMovable() ) {
2343                                 // Less specific message for rarer cases
2344                                 $errors[] = [ 'immobile-source-page' ];
2345                         }
2346                 } elseif ( $action == 'move-target' ) {
2347                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2348                                 $errors[] = [ 'immobile-target-namespace', $this->getNsText() ];
2349                         } elseif ( !$this->isMovable() ) {
2350                                 $errors[] = [ 'immobile-target-page' ];
2351                         }
2352                 } elseif ( $action == 'delete' ) {
2353                         $tempErrors = $this->checkPageRestrictions( 'edit', $user, [], $rigor, true );
2354                         if ( !$tempErrors ) {
2355                                 $tempErrors = $this->checkCascadingSourcesRestrictions( 'edit',
2356                                         $user, $tempErrors, $rigor, true );
2357                         }
2358                         if ( $tempErrors ) {
2359                                 // If protection keeps them from editing, they shouldn't be able to delete.
2360                                 $errors[] = [ 'deleteprotected' ];
2361                         }
2362                         if ( $rigor !== 'quick' && $wgDeleteRevisionsLimit
2363                                 && !$this->userCan( 'bigdelete', $user ) && $this->isBigDeletion()
2364                         ) {
2365                                 $errors[] = [ 'delete-toobig', $wgLang->formatNum( $wgDeleteRevisionsLimit ) ];
2366                         }
2367                 } elseif ( $action === 'undelete' ) {
2368                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit', $user, $rigor, true ) ) ) {
2369                                 // Undeleting implies editing
2370                                 $errors[] = [ 'undelete-cantedit' ];
2371                         }
2372                         if ( !$this->exists()
2373                                 && count( $this->getUserPermissionsErrorsInternal( 'create', $user, $rigor, true ) )
2374                         ) {
2375                                 // Undeleting where nothing currently exists implies creating
2376                                 $errors[] = [ 'undelete-cantcreate' ];
2377                         }
2378                 }
2379                 return $errors;
2380         }
2381
2382         /**
2383          * Check that the user isn't blocked from editing.
2384          *
2385          * @param string $action The action to check
2386          * @param User $user User to check
2387          * @param array $errors List of current errors
2388          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2389          * @param bool $short Short circuit on first error
2390          *
2391          * @return array List of errors
2392          */
2393         private function checkUserBlock( $action, $user, $errors, $rigor, $short ) {
2394                 global $wgEmailConfirmToEdit, $wgBlockDisablesLogin;
2395                 // Account creation blocks handled at userlogin.
2396                 // Unblocking handled in SpecialUnblock
2397                 if ( $rigor === 'quick' || in_array( $action, [ 'createaccount', 'unblock' ] ) ) {
2398                         return $errors;
2399                 }
2400
2401                 // Optimize for a very common case
2402                 if ( $action === 'read' && !$wgBlockDisablesLogin ) {
2403                         return $errors;
2404                 }
2405
2406                 if ( $wgEmailConfirmToEdit && !$user->isEmailConfirmed() ) {
2407                         $errors[] = [ 'confirmedittext' ];
2408                 }
2409
2410                 $useSlave = ( $rigor !== 'secure' );
2411                 if ( ( $action == 'edit' || $action == 'create' )
2412                         && !$user->isBlockedFrom( $this, $useSlave )
2413                 ) {
2414                         // Don't block the user from editing their own talk page unless they've been
2415                         // explicitly blocked from that too.
2416                 } elseif ( $user->isBlocked() && $user->getBlock()->prevents( $action ) !== false ) {
2417                         // @todo FIXME: Pass the relevant context into this function.
2418                         $errors[] = $user->getBlock()->getPermissionsError( RequestContext::getMain() );
2419                 }
2420
2421                 return $errors;
2422         }
2423
2424         /**
2425          * Check that the user is allowed to read this page.
2426          *
2427          * @param string $action The action to check
2428          * @param User $user User to check
2429          * @param array $errors List of current errors
2430          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2431          * @param bool $short Short circuit on first error
2432          *
2433          * @return array List of errors
2434          */
2435         private function checkReadPermissions( $action, $user, $errors, $rigor, $short ) {
2436                 global $wgWhitelistRead, $wgWhitelistReadRegexp;
2437
2438                 $whitelisted = false;
2439                 if ( User::isEveryoneAllowed( 'read' ) ) {
2440                         # Shortcut for public wikis, allows skipping quite a bit of code
2441                         $whitelisted = true;
2442                 } elseif ( $user->isAllowed( 'read' ) ) {
2443                         # If the user is allowed to read pages, he is allowed to read all pages
2444                         $whitelisted = true;
2445                 } elseif ( $this->isSpecial( 'Userlogin' )
2446                         || $this->isSpecial( 'PasswordReset' )
2447                         || $this->isSpecial( 'Userlogout' )
2448                 ) {
2449                         # Always grant access to the login page.
2450                         # Even anons need to be able to log in.
2451                         $whitelisted = true;
2452                 } elseif ( is_array( $wgWhitelistRead ) && count( $wgWhitelistRead ) ) {
2453                         # Time to check the whitelist
2454                         # Only do these checks is there's something to check against
2455                         $name = $this->getPrefixedText();
2456                         $dbName = $this->getPrefixedDBkey();
2457
2458                         // Check for explicit whitelisting with and without underscores
2459                         if ( in_array( $name, $wgWhitelistRead, true ) || in_array( $dbName, $wgWhitelistRead, true ) ) {
2460                                 $whitelisted = true;
2461                         } elseif ( $this->getNamespace() == NS_MAIN ) {
2462                                 # Old settings might have the title prefixed with
2463                                 # a colon for main-namespace pages
2464                                 if ( in_array( ':' . $name, $wgWhitelistRead ) ) {
2465                                         $whitelisted = true;
2466                                 }
2467                         } elseif ( $this->isSpecialPage() ) {
2468                                 # If it's a special page, ditch the subpage bit and check again
2469                                 $name = $this->getDBkey();
2470                                 list( $name, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $name );
2471                                 if ( $name ) {
2472                                         $pure = SpecialPage::getTitleFor( $name )->getPrefixedText();
2473                                         if ( in_array( $pure, $wgWhitelistRead, true ) ) {
2474                                                 $whitelisted = true;
2475                                         }
2476                                 }
2477                         }
2478                 }
2479
2480                 if ( !$whitelisted && is_array( $wgWhitelistReadRegexp ) && !empty( $wgWhitelistReadRegexp ) ) {
2481                         $name = $this->getPrefixedText();
2482                         // Check for regex whitelisting
2483                         foreach ( $wgWhitelistReadRegexp as $listItem ) {
2484                                 if ( preg_match( $listItem, $name ) ) {
2485                                         $whitelisted = true;
2486                                         break;
2487                                 }
2488                         }
2489                 }
2490
2491                 if ( !$whitelisted ) {
2492                         # If the title is not whitelisted, give extensions a chance to do so...
2493                         Hooks::run( 'TitleReadWhitelist', [ $this, $user, &$whitelisted ] );
2494                         if ( !$whitelisted ) {
2495                                 $errors[] = $this->missingPermissionError( $action, $short );
2496                         }
2497                 }
2498
2499                 return $errors;
2500         }
2501
2502         /**
2503          * Get a description array when the user doesn't have the right to perform
2504          * $action (i.e. when User::isAllowed() returns false)
2505          *
2506          * @param string $action The action to check
2507          * @param bool $short Short circuit on first error
2508          * @return array Array containing an error message key and any parameters
2509          */
2510         private function missingPermissionError( $action, $short ) {
2511                 // We avoid expensive display logic for quickUserCan's and such
2512                 if ( $short ) {
2513                         return [ 'badaccess-group0' ];
2514                 }
2515
2516                 return User::newFatalPermissionDeniedStatus( $action )->getErrorsArray()[0];
2517         }
2518
2519         /**
2520          * Can $user perform $action on this page? This is an internal function,
2521          * with multiple levels of checks depending on performance needs; see $rigor below.
2522          * It does not check wfReadOnly().
2523          *
2524          * @param string $action Action that permission needs to be checked for
2525          * @param User $user User to check
2526          * @param string $rigor One of (quick,full,secure)
2527          *   - quick  : does cheap permission checks from replica DBs (usable for GUI creation)
2528          *   - full   : does cheap and expensive checks possibly from a replica DB
2529          *   - secure : does cheap and expensive checks, using the master as needed
2530          * @param bool $short Set this to true to stop after the first permission error.
2531          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
2532          */
2533         protected function getUserPermissionsErrorsInternal(
2534                 $action, $user, $rigor = 'secure', $short = false
2535         ) {
2536                 if ( $rigor === true ) {
2537                         $rigor = 'secure'; // b/c
2538                 } elseif ( $rigor === false ) {
2539                         $rigor = 'quick'; // b/c
2540                 } elseif ( !in_array( $rigor, [ 'quick', 'full', 'secure' ] ) ) {
2541                         throw new Exception( "Invalid rigor parameter '$rigor'." );
2542                 }
2543
2544                 # Read has special handling
2545                 if ( $action == 'read' ) {
2546                         $checks = [
2547                                 'checkPermissionHooks',
2548                                 'checkReadPermissions',
2549                                 'checkUserBlock', // for wgBlockDisablesLogin
2550                         ];
2551                 # Don't call checkSpecialsAndNSPermissions or checkCSSandJSPermissions
2552                 # here as it will lead to duplicate error messages. This is okay to do
2553                 # since anywhere that checks for create will also check for edit, and
2554                 # those checks are called for edit.
2555                 } elseif ( $action == 'create' ) {
2556                         $checks = [
2557                                 'checkQuickPermissions',
2558                                 'checkPermissionHooks',
2559                                 'checkPageRestrictions',
2560                                 'checkCascadingSourcesRestrictions',
2561                                 'checkActionPermissions',
2562                                 'checkUserBlock'
2563                         ];
2564                 } else {
2565                         $checks = [
2566                                 'checkQuickPermissions',
2567                                 'checkPermissionHooks',
2568                                 'checkSpecialsAndNSPermissions',
2569                                 'checkCSSandJSPermissions',
2570                                 'checkPageRestrictions',
2571                                 'checkCascadingSourcesRestrictions',
2572                                 'checkActionPermissions',
2573                                 'checkUserBlock'
2574                         ];
2575                 }
2576
2577                 $errors = [];
2578                 while ( count( $checks ) > 0 &&
2579                                 !( $short && count( $errors ) > 0 ) ) {
2580                         $method = array_shift( $checks );
2581                         $errors = $this->$method( $action, $user, $errors, $rigor, $short );
2582                 }
2583
2584                 return $errors;
2585         }
2586
2587         /**
2588          * Get a filtered list of all restriction types supported by this wiki.
2589          * @param bool $exists True to get all restriction types that apply to
2590          * titles that do exist, False for all restriction types that apply to
2591          * titles that do not exist
2592          * @return array
2593          */
2594         public static function getFilteredRestrictionTypes( $exists = true ) {
2595                 global $wgRestrictionTypes;
2596                 $types = $wgRestrictionTypes;
2597                 if ( $exists ) {
2598                         # Remove the create restriction for existing titles
2599                         $types = array_diff( $types, [ 'create' ] );
2600                 } else {
2601                         # Only the create and upload restrictions apply to non-existing titles
2602                         $types = array_intersect( $types, [ 'create', 'upload' ] );
2603                 }
2604                 return $types;
2605         }
2606
2607         /**
2608          * Returns restriction types for the current Title
2609          *
2610          * @return array Applicable restriction types
2611          */
2612         public function getRestrictionTypes() {
2613                 if ( $this->isSpecialPage() ) {
2614                         return [];
2615                 }
2616
2617                 $types = self::getFilteredRestrictionTypes( $this->exists() );
2618
2619                 if ( $this->getNamespace() != NS_FILE ) {
2620                         # Remove the upload restriction for non-file titles
2621                         $types = array_diff( $types, [ 'upload' ] );
2622                 }
2623
2624                 Hooks::run( 'TitleGetRestrictionTypes', [ $this, &$types ] );
2625
2626                 wfDebug( __METHOD__ . ': applicable restrictions to [[' .
2627                         $this->getPrefixedText() . ']] are {' . implode( ',', $types ) . "}\n" );
2628
2629                 return $types;
2630         }
2631
2632         /**
2633          * Is this title subject to title protection?
2634          * Title protection is the one applied against creation of such title.
2635          *
2636          * @return array|bool An associative array representing any existent title
2637          *   protection, or false if there's none.
2638          */
2639         public function getTitleProtection() {
2640                 $protection = $this->getTitleProtectionInternal();
2641                 if ( $protection ) {
2642                         if ( $protection['permission'] == 'sysop' ) {
2643                                 $protection['permission'] = 'editprotected'; // B/C
2644                         }
2645                         if ( $protection['permission'] == 'autoconfirmed' ) {
2646                                 $protection['permission'] = 'editsemiprotected'; // B/C
2647                         }
2648                 }
2649                 return $protection;
2650         }
2651
2652         /**
2653          * Fetch title protection settings
2654          *
2655          * To work correctly, $this->loadRestrictions() needs to have access to the
2656          * actual protections in the database without munging 'sysop' =>
2657          * 'editprotected' and 'autoconfirmed' => 'editsemiprotected'. Other
2658          * callers probably want $this->getTitleProtection() instead.
2659          *
2660          * @return array|bool
2661          */
2662         protected function getTitleProtectionInternal() {
2663                 // Can't protect pages in special namespaces
2664                 if ( $this->getNamespace() < 0 ) {
2665                         return false;
2666                 }
2667
2668                 // Can't protect pages that exist.
2669                 if ( $this->exists() ) {
2670                         return false;
2671                 }
2672
2673                 if ( $this->mTitleProtection === null ) {
2674                         $dbr = wfGetDB( DB_REPLICA );
2675                         $res = $dbr->select(
2676                                 'protected_titles',
2677                                 [
2678                                         'user' => 'pt_user',
2679                                         'reason' => 'pt_reason',
2680                                         'expiry' => 'pt_expiry',
2681                                         'permission' => 'pt_create_perm'
2682                                 ],
2683                                 [ 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ],
2684                                 __METHOD__
2685                         );
2686
2687                         // fetchRow returns false if there are no rows.
2688                         $row = $dbr->fetchRow( $res );
2689                         if ( $row ) {
2690                                 $row['expiry'] = $dbr->decodeExpiry( $row['expiry'] );
2691                         }
2692                         $this->mTitleProtection = $row;
2693                 }
2694                 return $this->mTitleProtection;
2695         }
2696
2697         /**
2698          * Remove any title protection due to page existing
2699          */
2700         public function deleteTitleProtection() {
2701                 $dbw = wfGetDB( DB_MASTER );
2702
2703                 $dbw->delete(
2704                         'protected_titles',
2705                         [ 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ],
2706                         __METHOD__
2707                 );
2708                 $this->mTitleProtection = false;
2709         }
2710
2711         /**
2712          * Is this page "semi-protected" - the *only* protection levels are listed
2713          * in $wgSemiprotectedRestrictionLevels?
2714          *
2715          * @param string $action Action to check (default: edit)
2716          * @return bool
2717          */
2718         public function isSemiProtected( $action = 'edit' ) {
2719                 global $wgSemiprotectedRestrictionLevels;
2720
2721                 $restrictions = $this->getRestrictions( $action );
2722                 $semi = $wgSemiprotectedRestrictionLevels;
2723                 if ( !$restrictions || !$semi ) {
2724                         // Not protected, or all protection is full protection
2725                         return false;
2726                 }
2727
2728                 // Remap autoconfirmed to editsemiprotected for BC
2729                 foreach ( array_keys( $semi, 'autoconfirmed' ) as $key ) {
2730                         $semi[$key] = 'editsemiprotected';
2731                 }
2732                 foreach ( array_keys( $restrictions, 'autoconfirmed' ) as $key ) {
2733                         $restrictions[$key] = 'editsemiprotected';
2734                 }
2735
2736                 return !array_diff( $restrictions, $semi );
2737         }
2738
2739         /**
2740          * Does the title correspond to a protected article?
2741          *
2742          * @param string $action The action the page is protected from,
2743          * by default checks all actions.
2744          * @return bool
2745          */
2746         public function isProtected( $action = '' ) {
2747                 global $wgRestrictionLevels;
2748
2749                 $restrictionTypes = $this->getRestrictionTypes();
2750
2751                 # Special pages have inherent protection
2752                 if ( $this->isSpecialPage() ) {
2753                         return true;
2754                 }
2755
2756                 # Check regular protection levels
2757                 foreach ( $restrictionTypes as $type ) {
2758                         if ( $action == $type || $action == '' ) {
2759                                 $r = $this->getRestrictions( $type );
2760                                 foreach ( $wgRestrictionLevels as $level ) {
2761                                         if ( in_array( $level, $r ) && $level != '' ) {
2762                                                 return true;
2763                                         }
2764                                 }
2765                         }
2766                 }
2767
2768                 return false;
2769         }
2770
2771         /**
2772          * Determines if $user is unable to edit this page because it has been protected
2773          * by $wgNamespaceProtection.
2774          *
2775          * @param User $user User object to check permissions
2776          * @return bool
2777          */
2778         public function isNamespaceProtected( User $user ) {
2779                 global $wgNamespaceProtection;
2780
2781                 if ( isset( $wgNamespaceProtection[$this->mNamespace] ) ) {
2782                         foreach ( (array)$wgNamespaceProtection[$this->mNamespace] as $right ) {
2783                                 if ( $right != '' && !$user->isAllowed( $right ) ) {
2784                                         return true;
2785                                 }
2786                         }
2787                 }
2788                 return false;
2789         }
2790
2791         /**
2792          * Cascading protection: Return true if cascading restrictions apply to this page, false if not.
2793          *
2794          * @return bool If the page is subject to cascading restrictions.
2795          */
2796         public function isCascadeProtected() {
2797                 list( $sources, /* $restrictions */ ) = $this->getCascadeProtectionSources( false );
2798                 return ( $sources > 0 );
2799         }
2800
2801         /**
2802          * Determines whether cascading protection sources have already been loaded from
2803          * the database.
2804          *
2805          * @param bool $getPages True to check if the pages are loaded, or false to check
2806          * if the status is loaded.
2807          * @return bool Whether or not the specified information has been loaded
2808          * @since 1.23
2809          */
2810         public function areCascadeProtectionSourcesLoaded( $getPages = true ) {
2811                 return $getPages ? $this->mCascadeSources !== null : $this->mHasCascadingRestrictions !== null;
2812         }
2813
2814         /**
2815          * Cascading protection: Get the source of any cascading restrictions on this page.
2816          *
2817          * @param bool $getPages Whether or not to retrieve the actual pages
2818          *        that the restrictions have come from and the actual restrictions
2819          *        themselves.
2820          * @return array Two elements: First is an array of Title objects of the
2821          *        pages from which cascading restrictions have come, false for
2822          *        none, or true if such restrictions exist but $getPages was not
2823          *        set. Second is an array like that returned by
2824          *        Title::getAllRestrictions(), or an empty array if $getPages is
2825          *        false.
2826          */
2827         public function getCascadeProtectionSources( $getPages = true ) {
2828                 $pagerestrictions = [];
2829
2830                 if ( $this->mCascadeSources !== null && $getPages ) {
2831                         return [ $this->mCascadeSources, $this->mCascadingRestrictions ];
2832                 } elseif ( $this->mHasCascadingRestrictions !== null && !$getPages ) {
2833                         return [ $this->mHasCascadingRestrictions, $pagerestrictions ];
2834                 }
2835
2836                 $dbr = wfGetDB( DB_REPLICA );
2837
2838                 if ( $this->getNamespace() == NS_FILE ) {
2839                         $tables = [ 'imagelinks', 'page_restrictions' ];
2840                         $where_clauses = [
2841                                 'il_to' => $this->getDBkey(),
2842                                 'il_from=pr_page',
2843                                 'pr_cascade' => 1
2844                         ];
2845                 } else {
2846                         $tables = [ 'templatelinks', 'page_restrictions' ];
2847                         $where_clauses = [
2848                                 'tl_namespace' => $this->getNamespace(),
2849                                 'tl_title' => $this->getDBkey(),
2850                                 'tl_from=pr_page',
2851                                 'pr_cascade' => 1
2852                         ];
2853                 }
2854
2855                 if ( $getPages ) {
2856                         $cols = [ 'pr_page', 'page_namespace', 'page_title',
2857                                 'pr_expiry', 'pr_type', 'pr_level' ];
2858                         $where_clauses[] = 'page_id=pr_page';
2859                         $tables[] = 'page';
2860                 } else {
2861                         $cols = [ 'pr_expiry' ];
2862                 }
2863
2864                 $res = $dbr->select( $tables, $cols, $where_clauses, __METHOD__ );
2865
2866                 $sources = $getPages ? [] : false;
2867                 $now = wfTimestampNow();
2868
2869                 foreach ( $res as $row ) {
2870                         $expiry = $dbr->decodeExpiry( $row->pr_expiry );
2871                         if ( $expiry > $now ) {
2872                                 if ( $getPages ) {
2873                                         $page_id = $row->pr_page;
2874                                         $page_ns = $row->page_namespace;
2875                                         $page_title = $row->page_title;
2876                                         $sources[$page_id] = self::makeTitle( $page_ns, $page_title );
2877                                         # Add groups needed for each restriction type if its not already there
2878                                         # Make sure this restriction type still exists
2879
2880                                         if ( !isset( $pagerestrictions[$row->pr_type] ) ) {
2881                                                 $pagerestrictions[$row->pr_type] = [];
2882                                         }
2883
2884                                         if (
2885                                                 isset( $pagerestrictions[$row->pr_type] )
2886                                                 && !in_array( $row->pr_level, $pagerestrictions[$row->pr_type] )
2887                                         ) {
2888                                                 $pagerestrictions[$row->pr_type][] = $row->pr_level;
2889                                         }
2890                                 } else {
2891                                         $sources = true;
2892                                 }
2893                         }
2894                 }
2895
2896                 if ( $getPages ) {
2897                         $this->mCascadeSources = $sources;
2898                         $this->mCascadingRestrictions = $pagerestrictions;
2899                 } else {
2900                         $this->mHasCascadingRestrictions = $sources;
2901                 }
2902
2903                 return [ $sources, $pagerestrictions ];
2904         }
2905
2906         /**
2907          * Accessor for mRestrictionsLoaded
2908          *
2909          * @return bool Whether or not the page's restrictions have already been
2910          * loaded from the database
2911          * @since 1.23
2912          */
2913         public function areRestrictionsLoaded() {
2914                 return $this->mRestrictionsLoaded;
2915         }
2916
2917         /**
2918          * Accessor/initialisation for mRestrictions
2919          *
2920          * @param string $action Action that permission needs to be checked for
2921          * @return array Restriction levels needed to take the action. All levels are
2922          *     required. Note that restriction levels are normally user rights, but 'sysop'
2923          *     and 'autoconfirmed' are also allowed for backwards compatibility. These should
2924          *     be mapped to 'editprotected' and 'editsemiprotected' respectively.
2925          */
2926         public function getRestrictions( $action ) {
2927                 if ( !$this->mRestrictionsLoaded ) {
2928                         $this->loadRestrictions();
2929                 }
2930                 return isset( $this->mRestrictions[$action] )
2931                                 ? $this->mRestrictions[$action]
2932                                 : [];
2933         }
2934
2935         /**
2936          * Accessor/initialisation for mRestrictions
2937          *
2938          * @return array Keys are actions, values are arrays as returned by
2939          *     Title::getRestrictions()
2940          * @since 1.23
2941          */
2942         public function getAllRestrictions() {
2943                 if ( !$this->mRestrictionsLoaded ) {
2944                         $this->loadRestrictions();
2945                 }
2946                 return $this->mRestrictions;
2947         }
2948
2949         /**
2950          * Get the expiry time for the restriction against a given action
2951          *
2952          * @param string $action
2953          * @return string|bool 14-char timestamp, or 'infinity' if the page is protected forever
2954          *     or not protected at all, or false if the action is not recognised.
2955          */
2956         public function getRestrictionExpiry( $action ) {
2957                 if ( !$this->mRestrictionsLoaded ) {
2958                         $this->loadRestrictions();
2959                 }
2960                 return isset( $this->mRestrictionsExpiry[$action] ) ? $this->mRestrictionsExpiry[$action] : false;
2961         }
2962
2963         /**
2964          * Returns cascading restrictions for the current article
2965          *
2966          * @return bool
2967          */
2968         function areRestrictionsCascading() {
2969                 if ( !$this->mRestrictionsLoaded ) {
2970                         $this->loadRestrictions();
2971                 }
2972
2973                 return $this->mCascadeRestriction;
2974         }
2975
2976         /**
2977          * Compiles list of active page restrictions from both page table (pre 1.10)
2978          * and page_restrictions table for this existing page.
2979          * Public for usage by LiquidThreads.
2980          *
2981          * @param array $rows Array of db result objects
2982          * @param string $oldFashionedRestrictions Comma-separated list of page
2983          *   restrictions from page table (pre 1.10)
2984          */
2985         public function loadRestrictionsFromRows( $rows, $oldFashionedRestrictions = null ) {
2986                 $dbr = wfGetDB( DB_REPLICA );
2987
2988                 $restrictionTypes = $this->getRestrictionTypes();
2989
2990                 foreach ( $restrictionTypes as $type ) {
2991                         $this->mRestrictions[$type] = [];
2992                         $this->mRestrictionsExpiry[$type] = 'infinity';
2993                 }
2994
2995                 $this->mCascadeRestriction = false;
2996
2997                 # Backwards-compatibility: also load the restrictions from the page record (old format).
2998                 if ( $oldFashionedRestrictions !== null ) {
2999                         $this->mOldRestrictions = $oldFashionedRestrictions;
3000                 }
3001
3002                 if ( $this->mOldRestrictions === false ) {
3003                         $this->mOldRestrictions = $dbr->selectField( 'page', 'page_restrictions',
3004                                 [ 'page_id' => $this->getArticleID() ], __METHOD__ );
3005                 }
3006
3007                 if ( $this->mOldRestrictions != '' ) {
3008                         foreach ( explode( ':', trim( $this->mOldRestrictions ) ) as $restrict ) {
3009                                 $temp = explode( '=', trim( $restrict ) );
3010                                 if ( count( $temp ) == 1 ) {
3011                                         // old old format should be treated as edit/move restriction
3012                                         $this->mRestrictions['edit'] = explode( ',', trim( $temp[0] ) );
3013                                         $this->mRestrictions['move'] = explode( ',', trim( $temp[0] ) );
3014                                 } else {
3015                                         $restriction = trim( $temp[1] );
3016                                         if ( $restriction != '' ) { // some old entries are empty
3017                                                 $this->mRestrictions[$temp[0]] = explode( ',', $restriction );
3018                                         }
3019                                 }
3020                         }
3021                 }
3022
3023                 if ( count( $rows ) ) {
3024                         # Current system - load second to make them override.
3025                         $now = wfTimestampNow();
3026
3027                         # Cycle through all the restrictions.
3028                         foreach ( $rows as $row ) {
3029                                 // Don't take care of restrictions types that aren't allowed
3030                                 if ( !in_array( $row->pr_type, $restrictionTypes ) ) {
3031                                         continue;
3032                                 }
3033
3034                                 $expiry = $dbr->decodeExpiry( $row->pr_expiry );
3035
3036                                 // Only apply the restrictions if they haven't expired!
3037                                 if ( !$expiry || $expiry > $now ) {
3038                                         $this->mRestrictionsExpiry[$row->pr_type] = $expiry;
3039                                         $this->mRestrictions[$row->pr_type] = explode( ',', trim( $row->pr_level ) );
3040
3041                                         $this->mCascadeRestriction |= $row->pr_cascade;
3042                                 }
3043                         }
3044                 }
3045
3046                 $this->mRestrictionsLoaded = true;
3047         }
3048
3049         /**
3050          * Load restrictions from the page_restrictions table
3051          *
3052          * @param string $oldFashionedRestrictions Comma-separated list of page
3053          *   restrictions from page table (pre 1.10)
3054          */
3055         public function loadRestrictions( $oldFashionedRestrictions = null ) {
3056                 if ( $this->mRestrictionsLoaded ) {
3057                         return;
3058                 }
3059
3060                 $id = $this->getArticleID();
3061                 if ( $id ) {
3062                         $cache = ObjectCache::getMainWANInstance();
3063                         $rows = $cache->getWithSetCallback(
3064                                 // Page protections always leave a new null revision
3065                                 $cache->makeKey( 'page-restrictions', $id, $this->getLatestRevID() ),
3066                                 $cache::TTL_DAY,
3067                                 function ( $curValue, &$ttl, array &$setOpts ) {
3068                                         $dbr = wfGetDB( DB_REPLICA );
3069
3070                                         $setOpts += Database::getCacheSetOptions( $dbr );
3071
3072                                         return iterator_to_array(
3073                                                 $dbr->select(
3074                                                         'page_restrictions',
3075                                                         [ 'pr_type', 'pr_expiry', 'pr_level', 'pr_cascade' ],
3076                                                         [ 'pr_page' => $this->getArticleID() ],
3077                                                         __METHOD__
3078                                                 )
3079                                         );
3080                                 }
3081                         );
3082
3083                         $this->loadRestrictionsFromRows( $rows, $oldFashionedRestrictions );
3084                 } else {
3085                         $title_protection = $this->getTitleProtectionInternal();
3086
3087                         if ( $title_protection ) {
3088                                 $now = wfTimestampNow();
3089                                 $expiry = wfGetDB( DB_REPLICA )->decodeExpiry( $title_protection['expiry'] );
3090
3091                                 if ( !$expiry || $expiry > $now ) {
3092                                         // Apply the restrictions
3093                                         $this->mRestrictionsExpiry['create'] = $expiry;
3094                                         $this->mRestrictions['create'] =
3095                                                 explode( ',', trim( $title_protection['permission'] ) );
3096                                 } else { // Get rid of the old restrictions
3097                                         $this->mTitleProtection = false;
3098                                 }
3099                         } else {
3100                                 $this->mRestrictionsExpiry['create'] = 'infinity';
3101                         }
3102                         $this->mRestrictionsLoaded = true;
3103                 }
3104         }
3105
3106         /**
3107          * Flush the protection cache in this object and force reload from the database.
3108          * This is used when updating protection from WikiPage::doUpdateRestrictions().
3109          */
3110         public function flushRestrictions() {
3111                 $this->mRestrictionsLoaded = false;
3112                 $this->mTitleProtection = null;
3113         }
3114
3115         /**
3116          * Purge expired restrictions from the page_restrictions table
3117          *
3118          * This will purge no more than $wgUpdateRowsPerQuery page_restrictions rows
3119          */
3120         static function purgeExpiredRestrictions() {
3121                 if ( wfReadOnly() ) {
3122                         return;
3123                 }
3124
3125                 DeferredUpdates::addUpdate( new AtomicSectionUpdate(
3126                         wfGetDB( DB_MASTER ),
3127                         __METHOD__,
3128                         function ( IDatabase $dbw, $fname ) {
3129                                 $config = MediaWikiServices::getInstance()->getMainConfig();
3130                                 $ids = $dbw->selectFieldValues(
3131                                         'page_restrictions',
3132                                         'pr_id',
3133                                         [ 'pr_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ],
3134                                         $fname,
3135                                         [ 'LIMIT' => $config->get( 'UpdateRowsPerQuery' ) ] // T135470
3136                                 );
3137                                 if ( $ids ) {
3138                                         $dbw->delete( 'page_restrictions', [ 'pr_id' => $ids ], $fname );
3139                                 }
3140                         }
3141                 ) );
3142
3143                 DeferredUpdates::addUpdate( new AtomicSectionUpdate(
3144                         wfGetDB( DB_MASTER ),
3145                         __METHOD__,
3146                         function ( IDatabase $dbw, $fname ) {
3147                                 $dbw->delete(
3148                                         'protected_titles',
3149                                         [ 'pt_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ],
3150                                         $fname
3151                                 );
3152                         }
3153                 ) );
3154         }
3155
3156         /**
3157          * Does this have subpages?  (Warning, usually requires an extra DB query.)
3158          *
3159          * @return bool
3160          */
3161         public function hasSubpages() {
3162                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
3163                         # Duh
3164                         return false;
3165                 }
3166
3167                 # We dynamically add a member variable for the purpose of this method
3168                 # alone to cache the result.  There's no point in having it hanging
3169                 # around uninitialized in every Title object; therefore we only add it
3170                 # if needed and don't declare it statically.
3171                 if ( $this->mHasSubpages === null ) {
3172                         $this->mHasSubpages = false;
3173                         $subpages = $this->getSubpages( 1 );
3174                         if ( $subpages instanceof TitleArray ) {
3175                                 $this->mHasSubpages = (bool)$subpages->count();
3176                         }
3177                 }
3178
3179                 return $this->mHasSubpages;
3180         }
3181
3182         /**
3183          * Get all subpages of this page.
3184          *
3185          * @param int $limit Maximum number of subpages to fetch; -1 for no limit
3186          * @return TitleArray|array TitleArray, or empty array if this page's namespace
3187          *  doesn't allow subpages
3188          */
3189         public function getSubpages( $limit = -1 ) {
3190                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3191                         return [];
3192                 }
3193
3194                 $dbr = wfGetDB( DB_REPLICA );
3195                 $conds['page_namespace'] = $this->getNamespace();
3196                 $conds[] = 'page_title ' . $dbr->buildLike( $this->getDBkey() . '/', $dbr->anyString() );
3197                 $options = [];
3198                 if ( $limit > -1 ) {
3199                         $options['LIMIT'] = $limit;
3200                 }
3201                 return TitleArray::newFromResult(
3202                         $dbr->select( 'page',
3203                                 [ 'page_id', 'page_namespace', 'page_title', 'page_is_redirect' ],
3204                                 $conds,
3205                                 __METHOD__,
3206                                 $options
3207                         )
3208                 );
3209         }
3210
3211         /**
3212          * Is there a version of this page in the deletion archive?
3213          *
3214          * @return int The number of archived revisions
3215          */
3216         public function isDeleted() {
3217                 if ( $this->getNamespace() < 0 ) {
3218                         $n = 0;
3219                 } else {
3220                         $dbr = wfGetDB( DB_REPLICA );
3221
3222                         $n = $dbr->selectField( 'archive', 'COUNT(*)',
3223                                 [ 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ],
3224                                 __METHOD__
3225                         );
3226                         if ( $this->getNamespace() == NS_FILE ) {
3227                                 $n += $dbr->selectField( 'filearchive', 'COUNT(*)',
3228                                         [ 'fa_name' => $this->getDBkey() ],
3229                                         __METHOD__
3230                                 );
3231                         }
3232                 }
3233                 return (int)$n;
3234         }
3235
3236         /**
3237          * Is there a version of this page in the deletion archive?
3238          *
3239          * @return bool
3240          */
3241         public function isDeletedQuick() {
3242                 if ( $this->getNamespace() < 0 ) {
3243                         return false;
3244                 }
3245                 $dbr = wfGetDB( DB_REPLICA );
3246                 $deleted = (bool)$dbr->selectField( 'archive', '1',
3247                         [ 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ],
3248                         __METHOD__
3249                 );
3250                 if ( !$deleted && $this->getNamespace() == NS_FILE ) {
3251                         $deleted = (bool)$dbr->selectField( 'filearchive', '1',
3252                                 [ 'fa_name' => $this->getDBkey() ],
3253                                 __METHOD__
3254                         );
3255                 }
3256                 return $deleted;
3257         }
3258
3259         /**
3260          * Get the article ID for this Title from the link cache,
3261          * adding it if necessary
3262          *
3263          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select
3264          *  for update
3265          * @return int The ID
3266          */
3267         public function getArticleID( $flags = 0 ) {
3268                 if ( $this->getNamespace() < 0 ) {
3269                         $this->mArticleID = 0;
3270                         return $this->mArticleID;
3271                 }
3272                 $linkCache = LinkCache::singleton();
3273                 if ( $flags & self::GAID_FOR_UPDATE ) {
3274                         $oldUpdate = $linkCache->forUpdate( true );
3275                         $linkCache->clearLink( $this );
3276                         $this->mArticleID = $linkCache->addLinkObj( $this );
3277                         $linkCache->forUpdate( $oldUpdate );
3278                 } else {
3279                         if ( -1 == $this->mArticleID ) {
3280                                 $this->mArticleID = $linkCache->addLinkObj( $this );
3281                         }
3282                 }
3283                 return $this->mArticleID;
3284         }
3285
3286         /**
3287          * Is this an article that is a redirect page?
3288          * Uses link cache, adding it if necessary
3289          *
3290          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3291          * @return bool
3292          */
3293         public function isRedirect( $flags = 0 ) {
3294                 if ( !is_null( $this->mRedirect ) ) {
3295                         return $this->mRedirect;
3296                 }
3297                 if ( !$this->getArticleID( $flags ) ) {
3298                         $this->mRedirect = false;
3299                         return $this->mRedirect;
3300                 }
3301
3302                 $linkCache = LinkCache::singleton();
3303                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3304                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'redirect' );
3305                 if ( $cached === null ) {
3306                         # Trust LinkCache's state over our own
3307                         # LinkCache is telling us that the page doesn't exist, despite there being cached
3308                         # data relating to an existing page in $this->mArticleID. Updaters should clear
3309                         # LinkCache as appropriate, or use $flags = Title::GAID_FOR_UPDATE. If that flag is
3310                         # set, then LinkCache will definitely be up to date here, since getArticleID() forces
3311                         # LinkCache to refresh its data from the master.
3312                         $this->mRedirect = false;
3313                         return $this->mRedirect;
3314                 }
3315
3316                 $this->mRedirect = (bool)$cached;
3317
3318                 return $this->mRedirect;
3319         }
3320
3321         /**
3322          * What is the length of this page?
3323          * Uses link cache, adding it if necessary
3324          *
3325          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3326          * @return int
3327          */
3328         public function getLength( $flags = 0 ) {
3329                 if ( $this->mLength != -1 ) {
3330                         return $this->mLength;
3331                 }
3332                 if ( !$this->getArticleID( $flags ) ) {
3333                         $this->mLength = 0;
3334                         return $this->mLength;
3335                 }
3336                 $linkCache = LinkCache::singleton();
3337                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3338                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'length' );
3339                 if ( $cached === null ) {
3340                         # Trust LinkCache's state over our own, as for isRedirect()
3341                         $this->mLength = 0;
3342                         return $this->mLength;
3343                 }
3344
3345                 $this->mLength = intval( $cached );
3346
3347                 return $this->mLength;
3348         }
3349
3350         /**
3351          * What is the page_latest field for this page?
3352          *
3353          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3354          * @return int Int or 0 if the page doesn't exist
3355          */
3356         public function getLatestRevID( $flags = 0 ) {
3357                 if ( !( $flags & self::GAID_FOR_UPDATE ) && $this->mLatestID !== false ) {
3358                         return intval( $this->mLatestID );
3359                 }
3360                 if ( !$this->getArticleID( $flags ) ) {
3361                         $this->mLatestID = 0;
3362                         return $this->mLatestID;
3363                 }
3364                 $linkCache = LinkCache::singleton();
3365                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3366                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'revision' );
3367                 if ( $cached === null ) {
3368                         # Trust LinkCache's state over our own, as for isRedirect()
3369                         $this->mLatestID = 0;
3370                         return $this->mLatestID;
3371                 }
3372
3373                 $this->mLatestID = intval( $cached );
3374
3375                 return $this->mLatestID;
3376         }
3377
3378         /**
3379          * This clears some fields in this object, and clears any associated
3380          * keys in the "bad links" section of the link cache.
3381          *
3382          * - This is called from WikiPage::doEditContent() and WikiPage::insertOn() to allow
3383          * loading of the new page_id. It's also called from
3384          * WikiPage::doDeleteArticleReal()
3385          *
3386          * @param int $newid The new Article ID
3387          */
3388         public function resetArticleID( $newid ) {
3389                 $linkCache = LinkCache::singleton();
3390                 $linkCache->clearLink( $this );
3391
3392                 if ( $newid === false ) {
3393                         $this->mArticleID = -1;
3394                 } else {
3395                         $this->mArticleID = intval( $newid );
3396                 }
3397                 $this->mRestrictionsLoaded = false;
3398                 $this->mRestrictions = [];
3399                 $this->mOldRestrictions = false;
3400                 $this->mRedirect = null;
3401                 $this->mLength = -1;
3402                 $this->mLatestID = false;
3403                 $this->mContentModel = false;
3404                 $this->mEstimateRevisions = null;
3405                 $this->mPageLanguage = false;
3406                 $this->mDbPageLanguage = false;
3407                 $this->mIsBigDeletion = null;
3408         }
3409
3410         public static function clearCaches() {
3411                 $linkCache = LinkCache::singleton();
3412                 $linkCache->clear();
3413
3414                 $titleCache = self::getTitleCache();
3415                 $titleCache->clear();
3416         }
3417
3418         /**
3419          * Capitalize a text string for a title if it belongs to a namespace that capitalizes
3420          *
3421          * @param string $text Containing title to capitalize
3422          * @param int $ns Namespace index, defaults to NS_MAIN
3423          * @return string Containing capitalized title
3424          */
3425         public static function capitalize( $text, $ns = NS_MAIN ) {
3426                 global $wgContLang;
3427
3428                 if ( MWNamespace::isCapitalized( $ns ) ) {
3429                         return $wgContLang->ucfirst( $text );
3430                 } else {
3431                         return $text;
3432                 }
3433         }
3434
3435         /**
3436          * Secure and split - main initialisation function for this object
3437          *
3438          * Assumes that mDbkeyform has been set, and is urldecoded
3439          * and uses underscores, but not otherwise munged.  This function
3440          * removes illegal characters, splits off the interwiki and
3441          * namespace prefixes, sets the other forms, and canonicalizes
3442          * everything.
3443          *
3444          * @throws MalformedTitleException On invalid titles
3445          * @return bool True on success
3446          */
3447         private function secureAndSplit() {
3448                 # Initialisation
3449                 $this->mInterwiki = '';
3450                 $this->mFragment = '';
3451                 $this->mNamespace = $this->mDefaultNamespace; # Usually NS_MAIN
3452
3453                 $dbkey = $this->mDbkeyform;
3454
3455                 // @note: splitTitleString() is a temporary hack to allow MediaWikiTitleCodec to share
3456                 //        the parsing code with Title, while avoiding massive refactoring.
3457                 // @todo: get rid of secureAndSplit, refactor parsing code.
3458                 // @note: getTitleParser() returns a TitleParser implementation which does not have a
3459                 //        splitTitleString method, but the only implementation (MediaWikiTitleCodec) does
3460                 $titleCodec = MediaWikiServices::getInstance()->getTitleParser();
3461                 // MalformedTitleException can be thrown here
3462                 $parts = $titleCodec->splitTitleString( $dbkey, $this->getDefaultNamespace() );
3463
3464                 # Fill fields
3465                 $this->setFragment( '#' . $parts['fragment'] );
3466                 $this->mInterwiki = $parts['interwiki'];
3467                 $this->mLocalInterwiki = $parts['local_interwiki'];
3468                 $this->mNamespace = $parts['namespace'];
3469                 $this->mUserCaseDBKey = $parts['user_case_dbkey'];
3470
3471                 $this->mDbkeyform = $parts['dbkey'];
3472                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
3473                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
3474
3475                 # We already know that some pages won't be in the database!
3476                 if ( $this->isExternal() || $this->isSpecialPage() ) {
3477                         $this->mArticleID = 0;
3478                 }
3479
3480                 return true;
3481         }
3482
3483         /**
3484          * Get an array of Title objects linking to this Title
3485          * Also stores the IDs in the link cache.
3486          *
3487          * WARNING: do not use this function on arbitrary user-supplied titles!
3488          * On heavily-used templates it will max out the memory.
3489          *
3490          * @param array $options May be FOR UPDATE
3491          * @param string $table Table name
3492          * @param string $prefix Fields prefix
3493          * @return Title[] Array of Title objects linking here
3494          */
3495         public function getLinksTo( $options = [], $table = 'pagelinks', $prefix = 'pl' ) {
3496                 if ( count( $options ) > 0 ) {
3497                         $db = wfGetDB( DB_MASTER );
3498                 } else {
3499                         $db = wfGetDB( DB_REPLICA );
3500                 }
3501
3502                 $res = $db->select(
3503                         [ 'page', $table ],
3504                         self::getSelectFields(),
3505                         [
3506                                 "{$prefix}_from=page_id",
3507                                 "{$prefix}_namespace" => $this->getNamespace(),
3508                                 "{$prefix}_title" => $this->getDBkey() ],
3509                         __METHOD__,
3510                         $options
3511                 );
3512
3513                 $retVal = [];
3514                 if ( $res->numRows() ) {
3515                         $linkCache = LinkCache::singleton();
3516                         foreach ( $res as $row ) {
3517                                 $titleObj = self::makeTitle( $row->page_namespace, $row->page_title );
3518                                 if ( $titleObj ) {
3519                                         $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3520                                         $retVal[] = $titleObj;
3521                                 }
3522                         }
3523                 }
3524                 return $retVal;
3525         }
3526
3527         /**
3528          * Get an array of Title objects using this Title as a template
3529          * Also stores the IDs in the link cache.
3530          *
3531          * WARNING: do not use this function on arbitrary user-supplied titles!
3532          * On heavily-used templates it will max out the memory.
3533          *
3534          * @param array $options Query option to Database::select()
3535          * @return Title[] Array of Title the Title objects linking here
3536          */
3537         public function getTemplateLinksTo( $options = [] ) {
3538                 return $this->getLinksTo( $options, 'templatelinks', 'tl' );
3539         }
3540
3541         /**
3542          * Get an array of Title objects linked from this Title
3543          * Also stores the IDs in the link cache.
3544          *
3545          * WARNING: do not use this function on arbitrary user-supplied titles!
3546          * On heavily-used templates it will max out the memory.
3547          *
3548          * @param array $options Query option to Database::select()
3549          * @param string $table Table name
3550          * @param string $prefix Fields prefix
3551          * @return array Array of Title objects linking here
3552          */
3553         public function getLinksFrom( $options = [], $table = 'pagelinks', $prefix = 'pl' ) {
3554                 $id = $this->getArticleID();
3555
3556                 # If the page doesn't exist; there can't be any link from this page
3557                 if ( !$id ) {
3558                         return [];
3559                 }
3560
3561                 $db = wfGetDB( DB_REPLICA );
3562
3563                 $blNamespace = "{$prefix}_namespace";
3564                 $blTitle = "{$prefix}_title";
3565
3566                 $res = $db->select(
3567                         [ $table, 'page' ],
3568                         array_merge(
3569                                 [ $blNamespace, $blTitle ],
3570                                 WikiPage::selectFields()
3571                         ),
3572                         [ "{$prefix}_from" => $id ],
3573                         __METHOD__,
3574                         $options,
3575                         [ 'page' => [
3576                                 'LEFT JOIN',
3577                                 [ "page_namespace=$blNamespace", "page_title=$blTitle" ]
3578                         ] ]
3579                 );
3580
3581                 $retVal = [];
3582                 $linkCache = LinkCache::singleton();
3583                 foreach ( $res as $row ) {
3584                         if ( $row->page_id ) {
3585                                 $titleObj = self::newFromRow( $row );
3586                         } else {
3587                                 $titleObj = self::makeTitle( $row->$blNamespace, $row->$blTitle );
3588                                 $linkCache->addBadLinkObj( $titleObj );
3589                         }
3590                         $retVal[] = $titleObj;
3591                 }
3592
3593                 return $retVal;
3594         }
3595
3596         /**
3597          * Get an array of Title objects used on this Title as a template
3598          * Also stores the IDs in the link cache.
3599          *
3600          * WARNING: do not use this function on arbitrary user-supplied titles!
3601          * On heavily-used templates it will max out the memory.
3602          *
3603          * @param array $options May be FOR UPDATE
3604          * @return Title[] Array of Title the Title objects used here
3605          */
3606         public function getTemplateLinksFrom( $options = [] ) {
3607                 return $this->getLinksFrom( $options, 'templatelinks', 'tl' );
3608         }
3609
3610         /**
3611          * Get an array of Title objects referring to non-existent articles linked
3612          * from this page.
3613          *
3614          * @todo check if needed (used only in SpecialBrokenRedirects.php, and
3615          *   should use redirect table in this case).
3616          * @return Title[] Array of Title the Title objects
3617          */
3618         public function getBrokenLinksFrom() {
3619                 if ( $this->getArticleID() == 0 ) {
3620                         # All links from article ID 0 are false positives
3621                         return [];
3622                 }
3623
3624                 $dbr = wfGetDB( DB_REPLICA );
3625                 $res = $dbr->select(
3626                         [ 'page', 'pagelinks' ],
3627                         [ 'pl_namespace', 'pl_title' ],
3628                         [
3629                                 'pl_from' => $this->getArticleID(),
3630                                 'page_namespace IS NULL'
3631                         ],
3632                         __METHOD__, [],
3633                         [
3634                                 'page' => [
3635                                         'LEFT JOIN',
3636                                         [ 'pl_namespace=page_namespace', 'pl_title=page_title' ]
3637                                 ]
3638                         ]
3639                 );
3640
3641                 $retVal = [];
3642                 foreach ( $res as $row ) {
3643                         $retVal[] = self::makeTitle( $row->pl_namespace, $row->pl_title );
3644                 }
3645                 return $retVal;
3646         }
3647
3648         /**
3649          * Get a list of URLs to purge from the CDN cache when this
3650          * page changes
3651          *
3652          * @return string[] Array of String the URLs
3653          */
3654         public function getCdnUrls() {
3655                 $urls = [
3656                         $this->getInternalURL(),
3657                         $this->getInternalURL( 'action=history' )
3658                 ];
3659
3660                 $pageLang = $this->getPageLanguage();
3661                 if ( $pageLang->hasVariants() ) {
3662                         $variants = $pageLang->getVariants();
3663                         foreach ( $variants as $vCode ) {
3664                                 $urls[] = $this->getInternalURL( $vCode );
3665                         }
3666                 }
3667
3668                 // If we are looking at a css/js user subpage, purge the action=raw.
3669                 if ( $this->isJsSubpage() ) {
3670                         $urls[] = $this->getInternalURL( 'action=raw&ctype=text/javascript' );
3671                 } elseif ( $this->isCssSubpage() ) {
3672                         $urls[] = $this->getInternalURL( 'action=raw&ctype=text/css' );
3673                 }
3674
3675                 Hooks::run( 'TitleSquidURLs', [ $this, &$urls ] );
3676                 return $urls;
3677         }
3678
3679         /**
3680          * @deprecated since 1.27 use getCdnUrls()
3681          */
3682         public function getSquidURLs() {
3683                 return $this->getCdnUrls();
3684         }
3685
3686         /**
3687          * Purge all applicable CDN URLs
3688          */
3689         public function purgeSquid() {
3690                 DeferredUpdates::addUpdate(
3691                         new CdnCacheUpdate( $this->getCdnUrls() ),
3692                         DeferredUpdates::PRESEND
3693                 );
3694         }
3695
3696         /**
3697          * Check whether a given move operation would be valid.
3698          * Returns true if ok, or a getUserPermissionsErrors()-like array otherwise
3699          *
3700          * @deprecated since 1.25, use MovePage's methods instead
3701          * @param Title &$nt The new title
3702          * @param bool $auth Whether to check user permissions (uses $wgUser)
3703          * @param string $reason Is the log summary of the move, used for spam checking
3704          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3705          */
3706         public function isValidMoveOperation( &$nt, $auth = true, $reason = '' ) {
3707                 global $wgUser;
3708
3709                 if ( !( $nt instanceof Title ) ) {
3710                         // Normally we'd add this to $errors, but we'll get
3711                         // lots of syntax errors if $nt is not an object
3712                         return [ [ 'badtitletext' ] ];
3713                 }
3714
3715                 $mp = new MovePage( $this, $nt );
3716                 $errors = $mp->isValidMove()->getErrorsArray();
3717                 if ( $auth ) {
3718                         $errors = wfMergeErrorArrays(
3719                                 $errors,
3720                                 $mp->checkPermissions( $wgUser, $reason )->getErrorsArray()
3721                         );
3722                 }
3723
3724                 return $errors ?: true;
3725         }
3726
3727         /**
3728          * Check if the requested move target is a valid file move target
3729          * @todo move this to MovePage
3730          * @param Title $nt Target title
3731          * @return array List of errors
3732          */
3733         protected function validateFileMoveOperation( $nt ) {
3734                 global $wgUser;
3735
3736                 $errors = [];
3737
3738                 $destFile = wfLocalFile( $nt );
3739                 $destFile->load( File::READ_LATEST );
3740                 if ( !$wgUser->isAllowed( 'reupload-shared' )
3741                         && !$destFile->exists() && wfFindFile( $nt )
3742                 ) {
3743                         $errors[] = [ 'file-exists-sharedrepo' ];
3744                 }
3745
3746                 return $errors;
3747         }
3748
3749         /**
3750          * Move a title to a new location
3751          *
3752          * @deprecated since 1.25, use the MovePage class instead
3753          * @param Title &$nt The new title
3754          * @param bool $auth Indicates whether $wgUser's permissions
3755          *  should be checked
3756          * @param string $reason The reason for the move
3757          * @param bool $createRedirect Whether to create a redirect from the old title to the new title.
3758          *  Ignored if the user doesn't have the suppressredirect right.
3759          * @param array $changeTags Applied to the entry in the move log and redirect page revision
3760          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3761          */
3762         public function moveTo( &$nt, $auth = true, $reason = '', $createRedirect = true,
3763                 array $changeTags = []
3764         ) {
3765                 global $wgUser;
3766                 $err = $this->isValidMoveOperation( $nt, $auth, $reason );
3767                 if ( is_array( $err ) ) {
3768                         // Auto-block user's IP if the account was "hard" blocked
3769                         $wgUser->spreadAnyEditBlock();
3770                         return $err;
3771                 }
3772                 // Check suppressredirect permission
3773                 if ( $auth && !$wgUser->isAllowed( 'suppressredirect' ) ) {
3774                         $createRedirect = true;
3775                 }
3776
3777                 $mp = new MovePage( $this, $nt );
3778                 $status = $mp->move( $wgUser, $reason, $createRedirect, $changeTags );
3779                 if ( $status->isOK() ) {
3780                         return true;
3781                 } else {
3782                         return $status->getErrorsArray();
3783                 }
3784         }
3785
3786         /**
3787          * Move this page's subpages to be subpages of $nt
3788          *
3789          * @param Title $nt Move target
3790          * @param bool $auth Whether $wgUser's permissions should be checked
3791          * @param string $reason The reason for the move
3792          * @param bool $createRedirect Whether to create redirects from the old subpages to
3793          *     the new ones Ignored if the user doesn't have the 'suppressredirect' right
3794          * @param array $changeTags Applied to the entry in the move log and redirect page revision
3795          * @return array Array with old page titles as keys, and strings (new page titles) or
3796          *     getUserPermissionsErrors()-like arrays (errors) as values, or a
3797          *     getUserPermissionsErrors()-like error array with numeric indices if
3798          *     no pages were moved
3799          */
3800         public function moveSubpages( $nt, $auth = true, $reason = '', $createRedirect = true,
3801                 array $changeTags = []
3802         ) {
3803                 global $wgMaximumMovedPages;
3804                 // Check permissions
3805                 if ( !$this->userCan( 'move-subpages' ) ) {
3806                         return [
3807                                 [ 'cant-move-subpages' ],
3808                         ];
3809                 }
3810                 // Do the source and target namespaces support subpages?
3811                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3812                         return [
3813                                 [ 'namespace-nosubpages', MWNamespace::getCanonicalName( $this->getNamespace() ) ],
3814                         ];
3815                 }
3816                 if ( !MWNamespace::hasSubpages( $nt->getNamespace() ) ) {
3817                         return [
3818                                 [ 'namespace-nosubpages', MWNamespace::getCanonicalName( $nt->getNamespace() ) ],
3819                         ];
3820                 }
3821
3822                 $subpages = $this->getSubpages( $wgMaximumMovedPages + 1 );
3823                 $retval = [];
3824                 $count = 0;
3825                 foreach ( $subpages as $oldSubpage ) {
3826                         $count++;
3827                         if ( $count > $wgMaximumMovedPages ) {
3828                                 $retval[$oldSubpage->getPrefixedText()] = [
3829                                         [ 'movepage-max-pages', $wgMaximumMovedPages ],
3830                                 ];
3831                                 break;
3832                         }
3833
3834                         // We don't know whether this function was called before
3835                         // or after moving the root page, so check both
3836                         // $this and $nt
3837                         if ( $oldSubpage->getArticleID() == $this->getArticleID()
3838                                 || $oldSubpage->getArticleID() == $nt->getArticleID()
3839                         ) {
3840                                 // When moving a page to a subpage of itself,
3841                                 // don't move it twice
3842                                 continue;
3843                         }
3844                         $newPageName = preg_replace(
3845                                         '#^' . preg_quote( $this->getDBkey(), '#' ) . '#',
3846                                         StringUtils::escapeRegexReplacement( $nt->getDBkey() ), # T23234
3847                                         $oldSubpage->getDBkey() );
3848                         if ( $oldSubpage->isTalkPage() ) {
3849                                 $newNs = $nt->getTalkPage()->getNamespace();
3850                         } else {
3851                                 $newNs = $nt->getSubjectPage()->getNamespace();
3852                         }
3853                         # T16385: we need makeTitleSafe because the new page names may
3854                         # be longer than 255 characters.
3855                         $newSubpage = self::makeTitleSafe( $newNs, $newPageName );
3856
3857                         $success = $oldSubpage->moveTo( $newSubpage, $auth, $reason, $createRedirect, $changeTags );
3858                         if ( $success === true ) {
3859                                 $retval[$oldSubpage->getPrefixedText()] = $newSubpage->getPrefixedText();
3860                         } else {
3861                                 $retval[$oldSubpage->getPrefixedText()] = $success;
3862                         }
3863                 }
3864                 return $retval;
3865         }
3866
3867         /**
3868          * Checks if this page is just a one-rev redirect.
3869          * Adds lock, so don't use just for light purposes.
3870          *
3871          * @return bool
3872          */
3873         public function isSingleRevRedirect() {
3874                 global $wgContentHandlerUseDB;
3875
3876                 $dbw = wfGetDB( DB_MASTER );
3877
3878                 # Is it a redirect?
3879                 $fields = [ 'page_is_redirect', 'page_latest', 'page_id' ];
3880                 if ( $wgContentHandlerUseDB ) {
3881                         $fields[] = 'page_content_model';
3882                 }
3883
3884                 $row = $dbw->selectRow( 'page',
3885                         $fields,
3886                         $this->pageCond(),
3887                         __METHOD__,
3888                         [ 'FOR UPDATE' ]
3889                 );
3890                 # Cache some fields we may want
3891                 $this->mArticleID = $row ? intval( $row->page_id ) : 0;
3892                 $this->mRedirect = $row ? (bool)$row->page_is_redirect : false;
3893                 $this->mLatestID = $row ? intval( $row->page_latest ) : false;
3894                 $this->mContentModel = $row && isset( $row->page_content_model )
3895                         ? strval( $row->page_content_model )
3896                         : false;
3897
3898                 if ( !$this->mRedirect ) {
3899                         return false;
3900                 }
3901                 # Does the article have a history?
3902                 $row = $dbw->selectField( [ 'page', 'revision' ],
3903                         'rev_id',
3904                         [ 'page_namespace' => $this->getNamespace(),
3905                                 'page_title' => $this->getDBkey(),
3906                                 'page_id=rev_page',
3907                                 'page_latest != rev_id'
3908                         ],
3909                         __METHOD__,
3910                         [ 'FOR UPDATE' ]
3911                 );
3912                 # Return true if there was no history
3913                 return ( $row === false );
3914         }
3915
3916         /**
3917          * Checks if $this can be moved to a given Title
3918          * - Selects for update, so don't call it unless you mean business
3919          *
3920          * @deprecated since 1.25, use MovePage's methods instead
3921          * @param Title $nt The new title to check
3922          * @return bool
3923          */
3924         public function isValidMoveTarget( $nt ) {
3925                 # Is it an existing file?
3926                 if ( $nt->getNamespace() == NS_FILE ) {
3927                         $file = wfLocalFile( $nt );
3928                         $file->load( File::READ_LATEST );
3929                         if ( $file->exists() ) {
3930                                 wfDebug( __METHOD__ . ": file exists\n" );
3931                                 return false;
3932                         }
3933                 }
3934                 # Is it a redirect with no history?
3935                 if ( !$nt->isSingleRevRedirect() ) {
3936                         wfDebug( __METHOD__ . ": not a one-rev redirect\n" );
3937                         return false;
3938                 }
3939                 # Get the article text
3940                 $rev = Revision::newFromTitle( $nt, false, Revision::READ_LATEST );
3941                 if ( !is_object( $rev ) ) {
3942                         return false;
3943                 }
3944                 $content = $rev->getContent();
3945                 # Does the redirect point to the source?
3946                 # Or is it a broken self-redirect, usually caused by namespace collisions?
3947                 $redirTitle = $content ? $content->getRedirectTarget() : null;
3948
3949                 if ( $redirTitle ) {
3950                         if ( $redirTitle->getPrefixedDBkey() != $this->getPrefixedDBkey() &&
3951                                 $redirTitle->getPrefixedDBkey() != $nt->getPrefixedDBkey() ) {
3952                                 wfDebug( __METHOD__ . ": redirect points to other page\n" );
3953                                 return false;
3954                         } else {
3955                                 return true;
3956                         }
3957                 } else {
3958                         # Fail safe (not a redirect after all. strange.)
3959                         wfDebug( __METHOD__ . ": failsafe: database sais " . $nt->getPrefixedDBkey() .
3960                                                 " is a redirect, but it doesn't contain a valid redirect.\n" );
3961                         return false;
3962                 }
3963         }
3964
3965         /**
3966          * Get categories to which this Title belongs and return an array of
3967          * categories' names.
3968          *
3969          * @return array Array of parents in the form:
3970          *     $parent => $currentarticle
3971          */
3972         public function getParentCategories() {
3973                 global $wgContLang;
3974
3975                 $data = [];
3976
3977                 $titleKey = $this->getArticleID();
3978
3979                 if ( $titleKey === 0 ) {
3980                         return $data;
3981                 }
3982
3983                 $dbr = wfGetDB( DB_REPLICA );
3984
3985                 $res = $dbr->select(
3986                         'categorylinks',
3987                         'cl_to',
3988                         [ 'cl_from' => $titleKey ],
3989                         __METHOD__
3990                 );
3991
3992                 if ( $res->numRows() > 0 ) {
3993                         foreach ( $res as $row ) {
3994                                 // $data[] = Title::newFromText($wgContLang->getNsText ( NS_CATEGORY ).':'.$row->cl_to);
3995                                 $data[$wgContLang->getNsText( NS_CATEGORY ) . ':' . $row->cl_to] = $this->getFullText();
3996                         }
3997                 }
3998                 return $data;
3999         }
4000
4001         /**
4002          * Get a tree of parent categories
4003          *
4004          * @param array $children Array with the children in the keys, to check for circular refs
4005          * @return array Tree of parent categories
4006          */
4007         public function getParentCategoryTree( $children = [] ) {
4008                 $stack = [];
4009                 $parents = $this->getParentCategories();
4010
4011                 if ( $parents ) {
4012                         foreach ( $parents as $parent => $current ) {
4013                                 if ( array_key_exists( $parent, $children ) ) {
4014                                         # Circular reference
4015                                         $stack[$parent] = [];
4016                                 } else {
4017                                         $nt = self::newFromText( $parent );
4018                                         if ( $nt ) {
4019                                                 $stack[$parent] = $nt->getParentCategoryTree( $children + [ $parent => 1 ] );
4020                                         }
4021                                 }
4022                         }
4023                 }
4024
4025                 return $stack;
4026         }
4027
4028         /**
4029          * Get an associative array for selecting this title from
4030          * the "page" table
4031          *
4032          * @return array Array suitable for the $where parameter of DB::select()
4033          */
4034         public function pageCond() {
4035                 if ( $this->mArticleID > 0 ) {
4036                         // PK avoids secondary lookups in InnoDB, shouldn't hurt other DBs
4037                         return [ 'page_id' => $this->mArticleID ];
4038                 } else {
4039                         return [ 'page_namespace' => $this->mNamespace, 'page_title' => $this->mDbkeyform ];
4040                 }
4041         }
4042
4043         /**
4044          * Get next/previous revision ID relative to another revision ID
4045          * @param int $revId Revision ID. Get the revision that was before this one.
4046          * @param int $flags Title::GAID_FOR_UPDATE
4047          * @param string $dir 'next' or 'prev'
4048          * @return int|bool New revision ID, or false if none exists
4049          */
4050         private function getRelativeRevisionID( $revId, $flags, $dir ) {
4051                 $revId = (int)$revId;
4052                 if ( $dir === 'next' ) {
4053                         $op = '>';
4054                         $sort = 'ASC';
4055                 } elseif ( $dir === 'prev' ) {
4056                         $op = '<';
4057                         $sort = 'DESC';
4058                 } else {
4059                         throw new InvalidArgumentException( '$dir must be "next" or "prev"' );
4060                 }
4061
4062                 if ( $flags & self::GAID_FOR_UPDATE ) {
4063                         $db = wfGetDB( DB_MASTER );
4064                 } else {
4065                         $db = wfGetDB( DB_REPLICA, 'contributions' );
4066                 }
4067
4068                 // Intentionally not caring if the specified revision belongs to this
4069                 // page. We only care about the timestamp.
4070                 $ts = $db->selectField( 'revision', 'rev_timestamp', [ 'rev_id' => $revId ], __METHOD__ );
4071                 if ( $ts === false ) {
4072                         $ts = $db->selectField( 'archive', 'ar_timestamp', [ 'ar_rev_id' => $revId ], __METHOD__ );
4073                         if ( $ts === false ) {
4074                                 // Or should this throw an InvalidArgumentException or something?
4075                                 return false;
4076                         }
4077                 }
4078                 $ts = $db->addQuotes( $ts );
4079
4080                 $revId = $db->selectField( 'revision', 'rev_id',
4081                         [
4082                                 'rev_page' => $this->getArticleID( $flags ),
4083                                 "rev_timestamp $op $ts OR (rev_timestamp = $ts AND rev_id $op $revId)"
4084                         ],
4085                         __METHOD__,
4086                         [
4087                                 'ORDER BY' => "rev_timestamp $sort, rev_id $sort",
4088                                 'IGNORE INDEX' => 'rev_timestamp', // Probably needed for T159319
4089                         ]
4090                 );
4091
4092                 if ( $revId === false ) {
4093                         return false;
4094                 } else {
4095                         return intval( $revId );
4096                 }
4097         }
4098
4099         /**
4100          * Get the revision ID of the previous revision
4101          *
4102          * @param int $revId Revision ID. Get the revision that was before this one.
4103          * @param int $flags Title::GAID_FOR_UPDATE
4104          * @return int|bool Old revision ID, or false if none exists
4105          */
4106         public function getPreviousRevisionID( $revId, $flags = 0 ) {
4107                 return $this->getRelativeRevisionID( $revId, $flags, 'prev' );
4108         }
4109
4110         /**
4111          * Get the revision ID of the next revision
4112          *
4113          * @param int $revId Revision ID. Get the revision that was after this one.
4114          * @param int $flags Title::GAID_FOR_UPDATE
4115          * @return int|bool Next revision ID, or false if none exists
4116          */
4117         public function getNextRevisionID( $revId, $flags = 0 ) {
4118                 return $this->getRelativeRevisionID( $revId, $flags, 'next' );
4119         }
4120
4121         /**
4122          * Get the first revision of the page
4123          *
4124          * @param int $flags Title::GAID_FOR_UPDATE
4125          * @return Revision|null If page doesn't exist
4126          */
4127         public function getFirstRevision( $flags = 0 ) {
4128                 $pageId = $this->getArticleID( $flags );
4129                 if ( $pageId ) {
4130                         $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_REPLICA );
4131                         $row = $db->selectRow( 'revision', Revision::selectFields(),
4132                                 [ 'rev_page' => $pageId ],
4133                                 __METHOD__,
4134                                 [
4135                                         'ORDER BY' => 'rev_timestamp ASC, rev_id ASC',
4136                                         'IGNORE INDEX' => 'rev_timestamp', // See T159319
4137                                 ]
4138                         );
4139                         if ( $row ) {
4140                                 return new Revision( $row );
4141                         }
4142                 }
4143                 return null;
4144         }
4145
4146         /**
4147          * Get the oldest revision timestamp of this page
4148          *
4149          * @param int $flags Title::GAID_FOR_UPDATE
4150          * @return string MW timestamp
4151          */
4152         public function getEarliestRevTime( $flags = 0 ) {
4153                 $rev = $this->getFirstRevision( $flags );
4154                 return $rev ? $rev->getTimestamp() : null;
4155         }
4156
4157         /**
4158          * Check if this is a new page
4159          *
4160          * @return bool
4161          */
4162         public function isNewPage() {
4163                 $dbr = wfGetDB( DB_REPLICA );
4164                 return (bool)$dbr->selectField( 'page', 'page_is_new', $this->pageCond(), __METHOD__ );
4165         }
4166
4167         /**
4168          * Check whether the number of revisions of this page surpasses $wgDeleteRevisionsLimit
4169          *
4170          * @return bool
4171          */
4172         public function isBigDeletion() {
4173                 global $wgDeleteRevisionsLimit;
4174
4175                 if ( !$wgDeleteRevisionsLimit ) {
4176                         return false;
4177                 }
4178
4179                 if ( $this->mIsBigDeletion === null ) {
4180                         $dbr = wfGetDB( DB_REPLICA );
4181
4182                         $revCount = $dbr->selectRowCount(
4183                                 'revision',
4184                                 '1',
4185                                 [ 'rev_page' => $this->getArticleID() ],
4186                                 __METHOD__,
4187                                 [ 'LIMIT' => $wgDeleteRevisionsLimit + 1 ]
4188                         );
4189
4190                         $this->mIsBigDeletion = $revCount > $wgDeleteRevisionsLimit;
4191                 }
4192
4193                 return $this->mIsBigDeletion;
4194         }
4195
4196         /**
4197          * Get the approximate revision count of this page.
4198          *
4199          * @return int
4200          */
4201         public function estimateRevisionCount() {
4202                 if ( !$this->exists() ) {
4203                         return 0;
4204                 }
4205
4206                 if ( $this->mEstimateRevisions === null ) {
4207                         $dbr = wfGetDB( DB_REPLICA );
4208                         $this->mEstimateRevisions = $dbr->estimateRowCount( 'revision', '*',
4209                                 [ 'rev_page' => $this->getArticleID() ], __METHOD__ );
4210                 }
4211
4212                 return $this->mEstimateRevisions;
4213         }
4214
4215         /**
4216          * Get the number of revisions between the given revision.
4217          * Used for diffs and other things that really need it.
4218          *
4219          * @param int|Revision $old Old revision or rev ID (first before range)
4220          * @param int|Revision $new New revision or rev ID (first after range)
4221          * @param int|null $max Limit of Revisions to count, will be incremented to detect truncations
4222          * @return int Number of revisions between these revisions.
4223          */
4224         public function countRevisionsBetween( $old, $new, $max = null ) {
4225                 if ( !( $old instanceof Revision ) ) {
4226                         $old = Revision::newFromTitle( $this, (int)$old );
4227                 }
4228                 if ( !( $new instanceof Revision ) ) {
4229                         $new = Revision::newFromTitle( $this, (int)$new );
4230                 }
4231                 if ( !$old || !$new ) {
4232                         return 0; // nothing to compare
4233                 }
4234                 $dbr = wfGetDB( DB_REPLICA );
4235                 $conds = [
4236                         'rev_page' => $this->getArticleID(),
4237                         'rev_timestamp > ' . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4238                         'rev_timestamp < ' . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4239                 ];
4240                 if ( $max !== null ) {
4241                         return $dbr->selectRowCount( 'revision', '1',
4242                                 $conds,
4243                                 __METHOD__,
4244                                 [ 'LIMIT' => $max + 1 ] // extra to detect truncation
4245                         );
4246                 } else {
4247                         return (int)$dbr->selectField( 'revision', 'count(*)', $conds, __METHOD__ );
4248                 }
4249         }
4250
4251         /**
4252          * Get the authors between the given revisions or revision IDs.
4253          * Used for diffs and other things that really need it.
4254          *
4255          * @since 1.23
4256          *
4257          * @param int|Revision $old Old revision or rev ID (first before range by default)
4258          * @param int|Revision $new New revision or rev ID (first after range by default)
4259          * @param int $limit Maximum number of authors
4260          * @param string|array $options (Optional): Single option, or an array of options:
4261          *     'include_old' Include $old in the range; $new is excluded.
4262          *     'include_new' Include $new in the range; $old is excluded.
4263          *     'include_both' Include both $old and $new in the range.
4264          *     Unknown option values are ignored.
4265          * @return array|null Names of revision authors in the range; null if not both revisions exist
4266          */
4267         public function getAuthorsBetween( $old, $new, $limit, $options = [] ) {
4268                 if ( !( $old instanceof Revision ) ) {
4269                         $old = Revision::newFromTitle( $this, (int)$old );
4270                 }
4271                 if ( !( $new instanceof Revision ) ) {
4272                         $new = Revision::newFromTitle( $this, (int)$new );
4273                 }
4274                 // XXX: what if Revision objects are passed in, but they don't refer to this title?
4275                 // Add $old->getPage() != $new->getPage() || $old->getPage() != $this->getArticleID()
4276                 // in the sanity check below?
4277                 if ( !$old || !$new ) {
4278                         return null; // nothing to compare
4279                 }
4280                 $authors = [];
4281                 $old_cmp = '>';
4282                 $new_cmp = '<';
4283                 $options = (array)$options;
4284                 if ( in_array( 'include_old', $options ) ) {
4285                         $old_cmp = '>=';
4286                 }
4287                 if ( in_array( 'include_new', $options ) ) {
4288                         $new_cmp = '<=';
4289                 }
4290                 if ( in_array( 'include_both', $options ) ) {
4291                         $old_cmp = '>=';
4292                         $new_cmp = '<=';
4293                 }
4294                 // No DB query needed if $old and $new are the same or successive revisions:
4295                 if ( $old->getId() === $new->getId() ) {
4296                         return ( $old_cmp === '>' && $new_cmp === '<' ) ?
4297                                 [] :
4298                                 [ $old->getUserText( Revision::RAW ) ];
4299                 } elseif ( $old->getId() === $new->getParentId() ) {
4300                         if ( $old_cmp === '>=' && $new_cmp === '<=' ) {
4301                                 $authors[] = $old->getUserText( Revision::RAW );
4302                                 if ( $old->getUserText( Revision::RAW ) != $new->getUserText( Revision::RAW ) ) {
4303                                         $authors[] = $new->getUserText( Revision::RAW );
4304                                 }
4305                         } elseif ( $old_cmp === '>=' ) {
4306                                 $authors[] = $old->getUserText( Revision::RAW );
4307                         } elseif ( $new_cmp === '<=' ) {
4308                                 $authors[] = $new->getUserText( Revision::RAW );
4309                         }
4310                         return $authors;
4311                 }
4312                 $dbr = wfGetDB( DB_REPLICA );
4313                 $res = $dbr->select( 'revision', 'DISTINCT rev_user_text',
4314                         [
4315                                 'rev_page' => $this->getArticleID(),
4316                                 "rev_timestamp $old_cmp " . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4317                                 "rev_timestamp $new_cmp " . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4318                         ], __METHOD__,
4319                         [ 'LIMIT' => $limit + 1 ] // add one so caller knows it was truncated
4320                 );
4321                 foreach ( $res as $row ) {
4322                         $authors[] = $row->rev_user_text;
4323                 }
4324                 return $authors;
4325         }
4326
4327         /**
4328          * Get the number of authors between the given revisions or revision IDs.
4329          * Used for diffs and other things that really need it.
4330          *
4331          * @param int|Revision $old Old revision or rev ID (first before range by default)
4332          * @param int|Revision $new New revision or rev ID (first after range by default)
4333          * @param int $limit Maximum number of authors
4334          * @param string|array $options (Optional): Single option, or an array of options:
4335          *     'include_old' Include $old in the range; $new is excluded.
4336          *     'include_new' Include $new in the range; $old is excluded.
4337          *     'include_both' Include both $old and $new in the range.
4338          *     Unknown option values are ignored.
4339          * @return int Number of revision authors in the range; zero if not both revisions exist
4340          */
4341         public function countAuthorsBetween( $old, $new, $limit, $options = [] ) {
4342                 $authors = $this->getAuthorsBetween( $old, $new, $limit, $options );
4343                 return $authors ? count( $authors ) : 0;
4344         }
4345
4346         /**
4347          * Compare with another title.
4348          *
4349          * @param Title $title
4350          * @return bool
4351          */
4352         public function equals( Title $title ) {
4353                 // Note: === is necessary for proper matching of number-like titles.
4354                 return $this->getInterwiki() === $title->getInterwiki()
4355                         && $this->getNamespace() == $title->getNamespace()
4356                         && $this->getDBkey() === $title->getDBkey();
4357         }
4358
4359         /**
4360          * Check if this title is a subpage of another title
4361          *
4362          * @param Title $title
4363          * @return bool
4364          */
4365         public function isSubpageOf( Title $title ) {
4366                 return $this->getInterwiki() === $title->getInterwiki()
4367                         && $this->getNamespace() == $title->getNamespace()
4368                         && strpos( $this->getDBkey(), $title->getDBkey() . '/' ) === 0;
4369         }
4370
4371         /**
4372          * Check if page exists.  For historical reasons, this function simply
4373          * checks for the existence of the title in the page table, and will
4374          * thus return false for interwiki links, special pages and the like.
4375          * If you want to know if a title can be meaningfully viewed, you should
4376          * probably call the isKnown() method instead.
4377          *
4378          * @param int $flags An optional bit field; may be Title::GAID_FOR_UPDATE to check
4379          *   from master/for update
4380          * @return bool
4381          */
4382         public function exists( $flags = 0 ) {
4383                 $exists = $this->getArticleID( $flags ) != 0;
4384                 Hooks::run( 'TitleExists', [ $this, &$exists ] );
4385                 return $exists;
4386         }
4387
4388         /**
4389          * Should links to this title be shown as potentially viewable (i.e. as
4390          * "bluelinks"), even if there's no record by this title in the page
4391          * table?
4392          *
4393          * This function is semi-deprecated for public use, as well as somewhat
4394          * misleadingly named.  You probably just want to call isKnown(), which
4395          * calls this function internally.
4396          *
4397          * (ISSUE: Most of these checks are cheap, but the file existence check
4398          * can potentially be quite expensive.  Including it here fixes a lot of
4399          * existing code, but we might want to add an optional parameter to skip
4400          * it and any other expensive checks.)
4401          *
4402          * @return bool
4403          */
4404         public function isAlwaysKnown() {
4405                 $isKnown = null;
4406
4407                 /**
4408                  * Allows overriding default behavior for determining if a page exists.
4409                  * If $isKnown is kept as null, regular checks happen. If it's
4410                  * a boolean, this value is returned by the isKnown method.
4411                  *
4412                  * @since 1.20
4413                  *
4414                  * @param Title $title
4415                  * @param bool|null $isKnown
4416                  */
4417                 Hooks::run( 'TitleIsAlwaysKnown', [ $this, &$isKnown ] );
4418
4419                 if ( !is_null( $isKnown ) ) {
4420                         return $isKnown;
4421                 }
4422
4423                 if ( $this->isExternal() ) {
4424                         return true;  // any interwiki link might be viewable, for all we know
4425                 }
4426
4427                 switch ( $this->mNamespace ) {
4428                         case NS_MEDIA:
4429                         case NS_FILE:
4430                                 // file exists, possibly in a foreign repo
4431                                 return (bool)wfFindFile( $this );
4432                         case NS_SPECIAL:
4433                                 // valid special page
4434                                 return SpecialPageFactory::exists( $this->getDBkey() );
4435                         case NS_MAIN:
4436                                 // selflink, possibly with fragment
4437                                 return $this->mDbkeyform == '';
4438                         case NS_MEDIAWIKI:
4439                                 // known system message
4440                                 return $this->hasSourceText() !== false;
4441                         default:
4442                                 return false;
4443                 }
4444         }
4445
4446         /**
4447          * Does this title refer to a page that can (or might) be meaningfully
4448          * viewed?  In particular, this function may be used to determine if
4449          * links to the title should be rendered as "bluelinks" (as opposed to
4450          * "redlinks" to non-existent pages).
4451          * Adding something else to this function will cause inconsistency
4452          * since LinkHolderArray calls isAlwaysKnown() and does its own
4453          * page existence check.
4454          *
4455          * @return bool
4456          */
4457         public function isKnown() {
4458                 return $this->isAlwaysKnown() || $this->exists();
4459         }
4460
4461         /**
4462          * Does this page have source text?
4463          *
4464          * @return bool
4465          */
4466         public function hasSourceText() {
4467                 if ( $this->exists() ) {
4468                         return true;
4469                 }
4470
4471                 if ( $this->mNamespace == NS_MEDIAWIKI ) {
4472                         // If the page doesn't exist but is a known system message, default
4473                         // message content will be displayed, same for language subpages-
4474                         // Use always content language to avoid loading hundreds of languages
4475                         // to get the link color.
4476                         global $wgContLang;
4477                         list( $name, ) = MessageCache::singleton()->figureMessage(
4478                                 $wgContLang->lcfirst( $this->getText() )
4479                         );
4480                         $message = wfMessage( $name )->inLanguage( $wgContLang )->useDatabase( false );
4481                         return $message->exists();
4482                 }
4483
4484                 return false;
4485         }
4486
4487         /**
4488          * Get the default message text or false if the message doesn't exist
4489          *
4490          * @return string|bool
4491          */
4492         public function getDefaultMessageText() {
4493                 global $wgContLang;
4494
4495                 if ( $this->getNamespace() != NS_MEDIAWIKI ) { // Just in case
4496                         return false;
4497                 }
4498
4499                 list( $name, $lang ) = MessageCache::singleton()->figureMessage(
4500                         $wgContLang->lcfirst( $this->getText() )
4501                 );
4502                 $message = wfMessage( $name )->inLanguage( $lang )->useDatabase( false );
4503
4504                 if ( $message->exists() ) {
4505                         return $message->plain();
4506                 } else {
4507                         return false;
4508                 }
4509         }
4510
4511         /**
4512          * Updates page_touched for this page; called from LinksUpdate.php
4513          *
4514          * @param string $purgeTime [optional] TS_MW timestamp
4515          * @return bool True if the update succeeded
4516          */
4517         public function invalidateCache( $purgeTime = null ) {
4518                 if ( wfReadOnly() ) {
4519                         return false;
4520                 } elseif ( $this->mArticleID === 0 ) {
4521                         return true; // avoid gap locking if we know it's not there
4522                 }
4523
4524                 $dbw = wfGetDB( DB_MASTER );
4525                 $dbw->onTransactionPreCommitOrIdle( function () {
4526                         ResourceLoaderWikiModule::invalidateModuleCache( $this, null, null, wfWikiID() );
4527                 } );
4528
4529                 $conds = $this->pageCond();
4530                 DeferredUpdates::addUpdate(
4531                         new AutoCommitUpdate(
4532                                 $dbw,
4533                                 __METHOD__,
4534                                 function ( IDatabase $dbw, $fname ) use ( $conds, $purgeTime ) {
4535                                         $dbTimestamp = $dbw->timestamp( $purgeTime ?: time() );
4536                                         $dbw->update(
4537                                                 'page',
4538                                                 [ 'page_touched' => $dbTimestamp ],
4539                                                 $conds + [ 'page_touched < ' . $dbw->addQuotes( $dbTimestamp ) ],
4540                                                 $fname
4541                                         );
4542                                         MediaWikiServices::getInstance()->getLinkCache()->invalidateTitle( $this );
4543                                 }
4544                         ),
4545                         DeferredUpdates::PRESEND
4546                 );
4547
4548                 return true;
4549         }
4550
4551         /**
4552          * Update page_touched timestamps and send CDN purge messages for
4553          * pages linking to this title. May be sent to the job queue depending
4554          * on the number of links. Typically called on create and delete.
4555          */
4556         public function touchLinks() {
4557                 DeferredUpdates::addUpdate( new HTMLCacheUpdate( $this, 'pagelinks' ) );
4558                 if ( $this->getNamespace() == NS_CATEGORY ) {
4559                         DeferredUpdates::addUpdate( new HTMLCacheUpdate( $this, 'categorylinks' ) );
4560                 }
4561         }
4562
4563         /**
4564          * Get the last touched timestamp
4565          *
4566          * @param IDatabase $db Optional db
4567          * @return string|false Last-touched timestamp
4568          */
4569         public function getTouched( $db = null ) {
4570                 if ( $db === null ) {
4571                         $db = wfGetDB( DB_REPLICA );
4572                 }
4573                 $touched = $db->selectField( 'page', 'page_touched', $this->pageCond(), __METHOD__ );
4574                 return $touched;
4575         }
4576
4577         /**
4578          * Get the timestamp when this page was updated since the user last saw it.
4579          *
4580          * @param User $user
4581          * @return string|null
4582          */
4583         public function getNotificationTimestamp( $user = null ) {
4584                 global $wgUser;
4585
4586                 // Assume current user if none given
4587                 if ( !$user ) {
4588                         $user = $wgUser;
4589                 }
4590                 // Check cache first
4591                 $uid = $user->getId();
4592                 if ( !$uid ) {
4593                         return false;
4594                 }
4595                 // avoid isset here, as it'll return false for null entries
4596                 if ( array_key_exists( $uid, $this->mNotificationTimestamp ) ) {
4597                         return $this->mNotificationTimestamp[$uid];
4598                 }
4599                 // Don't cache too much!
4600                 if ( count( $this->mNotificationTimestamp ) >= self::CACHE_MAX ) {
4601                         $this->mNotificationTimestamp = [];
4602                 }
4603
4604                 $store = MediaWikiServices::getInstance()->getWatchedItemStore();
4605                 $watchedItem = $store->getWatchedItem( $user, $this );
4606                 if ( $watchedItem ) {
4607                         $this->mNotificationTimestamp[$uid] = $watchedItem->getNotificationTimestamp();
4608                 } else {
4609                         $this->mNotificationTimestamp[$uid] = false;
4610                 }
4611
4612                 return $this->mNotificationTimestamp[$uid];
4613         }
4614
4615         /**
4616          * Generate strings used for xml 'id' names in monobook tabs
4617          *
4618          * @param string $prepend Defaults to 'nstab-'
4619          * @return string XML 'id' name
4620          */
4621         public function getNamespaceKey( $prepend = 'nstab-' ) {
4622                 global $wgContLang;
4623                 // Gets the subject namespace if this title
4624                 $namespace = MWNamespace::getSubject( $this->getNamespace() );
4625                 // Checks if canonical namespace name exists for namespace
4626                 if ( MWNamespace::exists( $this->getNamespace() ) ) {
4627                         // Uses canonical namespace name
4628                         $namespaceKey = MWNamespace::getCanonicalName( $namespace );
4629                 } else {
4630                         // Uses text of namespace
4631                         $namespaceKey = $this->getSubjectNsText();
4632                 }
4633                 // Makes namespace key lowercase
4634                 $namespaceKey = $wgContLang->lc( $namespaceKey );
4635                 // Uses main
4636                 if ( $namespaceKey == '' ) {
4637                         $namespaceKey = 'main';
4638                 }
4639                 // Changes file to image for backwards compatibility
4640                 if ( $namespaceKey == 'file' ) {
4641                         $namespaceKey = 'image';
4642                 }
4643                 return $prepend . $namespaceKey;
4644         }
4645
4646         /**
4647          * Get all extant redirects to this Title
4648          *
4649          * @param int|null $ns Single namespace to consider; null to consider all namespaces
4650          * @return Title[] Array of Title redirects to this title
4651          */
4652         public function getRedirectsHere( $ns = null ) {
4653                 $redirs = [];
4654
4655                 $dbr = wfGetDB( DB_REPLICA );
4656                 $where = [
4657                         'rd_namespace' => $this->getNamespace(),
4658                         'rd_title' => $this->getDBkey(),
4659                         'rd_from = page_id'
4660                 ];
4661                 if ( $this->isExternal() ) {
4662                         $where['rd_interwiki'] = $this->getInterwiki();
4663                 } else {
4664                         $where[] = 'rd_interwiki = ' . $dbr->addQuotes( '' ) . ' OR rd_interwiki IS NULL';
4665                 }
4666                 if ( !is_null( $ns ) ) {
4667                         $where['page_namespace'] = $ns;
4668                 }
4669
4670                 $res = $dbr->select(
4671                         [ 'redirect', 'page' ],
4672                         [ 'page_namespace', 'page_title' ],
4673                         $where,
4674                         __METHOD__
4675                 );
4676
4677                 foreach ( $res as $row ) {
4678                         $redirs[] = self::newFromRow( $row );
4679                 }
4680                 return $redirs;
4681         }
4682
4683         /**
4684          * Check if this Title is a valid redirect target
4685          *
4686          * @return bool
4687          */
4688         public function isValidRedirectTarget() {
4689                 global $wgInvalidRedirectTargets;
4690
4691                 if ( $this->isSpecialPage() ) {
4692                         // invalid redirect targets are stored in a global array, but explicitly disallow Userlogout here
4693                         if ( $this->isSpecial( 'Userlogout' ) ) {
4694                                 return false;
4695                         }
4696
4697                         foreach ( $wgInvalidRedirectTargets as $target ) {
4698                                 if ( $this->isSpecial( $target ) ) {
4699                                         return false;
4700                                 }
4701                         }
4702                 }
4703
4704                 return true;
4705         }
4706
4707         /**
4708          * Get a backlink cache object
4709          *
4710          * @return BacklinkCache
4711          */
4712         public function getBacklinkCache() {
4713                 return BacklinkCache::get( $this );
4714         }
4715
4716         /**
4717          * Whether the magic words __INDEX__ and __NOINDEX__ function for this page.
4718          *
4719          * @return bool
4720          */
4721         public function canUseNoindex() {
4722                 global $wgExemptFromUserRobotsControl;
4723
4724                 $bannedNamespaces = is_null( $wgExemptFromUserRobotsControl )
4725                         ? MWNamespace::getContentNamespaces()
4726                         : $wgExemptFromUserRobotsControl;
4727
4728                 return !in_array( $this->mNamespace, $bannedNamespaces );
4729         }
4730
4731         /**
4732          * Returns the raw sort key to be used for categories, with the specified
4733          * prefix.  This will be fed to Collation::getSortKey() to get a
4734          * binary sortkey that can be used for actual sorting.
4735          *
4736          * @param string $prefix The prefix to be used, specified using
4737          *   {{defaultsort:}} or like [[Category:Foo|prefix]].  Empty for no
4738          *   prefix.
4739          * @return string
4740          */
4741         public function getCategorySortkey( $prefix = '' ) {
4742                 $unprefixed = $this->getText();
4743
4744                 // Anything that uses this hook should only depend
4745                 // on the Title object passed in, and should probably
4746                 // tell the users to run updateCollations.php --force
4747                 // in order to re-sort existing category relations.
4748                 Hooks::run( 'GetDefaultSortkey', [ $this, &$unprefixed ] );
4749                 if ( $prefix !== '' ) {
4750                         # Separate with a line feed, so the unprefixed part is only used as
4751                         # a tiebreaker when two pages have the exact same prefix.
4752                         # In UCA, tab is the only character that can sort above LF
4753                         # so we strip both of them from the original prefix.
4754                         $prefix = strtr( $prefix, "\n\t", '  ' );
4755                         return "$prefix\n$unprefixed";
4756                 }
4757                 return $unprefixed;
4758         }
4759
4760         /**
4761          * Returns the page language code saved in the database, if $wgPageLanguageUseDB is set
4762          * to true in LocalSettings.php, otherwise returns false. If there is no language saved in
4763          * the db, it will return NULL.
4764          *
4765          * @return string|null|bool
4766          */
4767         private function getDbPageLanguageCode() {
4768                 global $wgPageLanguageUseDB;
4769
4770                 // check, if the page language could be saved in the database, and if so and
4771                 // the value is not requested already, lookup the page language using LinkCache
4772                 if ( $wgPageLanguageUseDB && $this->mDbPageLanguage === false ) {
4773                         $linkCache = LinkCache::singleton();
4774                         $linkCache->addLinkObj( $this );
4775                         $this->mDbPageLanguage = $linkCache->getGoodLinkFieldObj( $this, 'lang' );
4776                 }
4777
4778                 return $this->mDbPageLanguage;
4779         }
4780
4781         /**
4782          * Get the language in which the content of this page is written in
4783          * wikitext. Defaults to $wgContLang, but in certain cases it can be
4784          * e.g. $wgLang (such as special pages, which are in the user language).
4785          *
4786          * @since 1.18
4787          * @return Language
4788          */
4789         public function getPageLanguage() {
4790                 global $wgLang, $wgLanguageCode;
4791                 if ( $this->isSpecialPage() ) {
4792                         // special pages are in the user language
4793                         return $wgLang;
4794                 }
4795
4796                 // Checking if DB language is set
4797                 $dbPageLanguage = $this->getDbPageLanguageCode();
4798                 if ( $dbPageLanguage ) {
4799                         return wfGetLangObj( $dbPageLanguage );
4800                 }
4801
4802                 if ( !$this->mPageLanguage || $this->mPageLanguage[1] !== $wgLanguageCode ) {
4803                         // Note that this may depend on user settings, so the cache should
4804                         // be only per-request.
4805                         // NOTE: ContentHandler::getPageLanguage() may need to load the
4806                         // content to determine the page language!
4807                         // Checking $wgLanguageCode hasn't changed for the benefit of unit
4808                         // tests.
4809                         $contentHandler = ContentHandler::getForTitle( $this );
4810                         $langObj = $contentHandler->getPageLanguage( $this );
4811                         $this->mPageLanguage = [ $langObj->getCode(), $wgLanguageCode ];
4812                 } else {
4813                         $langObj = wfGetLangObj( $this->mPageLanguage[0] );
4814                 }
4815
4816                 return $langObj;
4817         }
4818
4819         /**
4820          * Get the language in which the content of this page is written when
4821          * viewed by user. Defaults to $wgContLang, but in certain cases it can be
4822          * e.g. $wgLang (such as special pages, which are in the user language).
4823          *
4824          * @since 1.20
4825          * @return Language
4826          */
4827         public function getPageViewLanguage() {
4828                 global $wgLang;
4829
4830                 if ( $this->isSpecialPage() ) {
4831                         // If the user chooses a variant, the content is actually
4832                         // in a language whose code is the variant code.
4833                         $variant = $wgLang->getPreferredVariant();
4834                         if ( $wgLang->getCode() !== $variant ) {
4835                                 return Language::factory( $variant );
4836                         }
4837
4838                         return $wgLang;
4839                 }
4840
4841                 // Checking if DB language is set
4842                 $dbPageLanguage = $this->getDbPageLanguageCode();
4843                 if ( $dbPageLanguage ) {
4844                         $pageLang = wfGetLangObj( $dbPageLanguage );
4845                         $variant = $pageLang->getPreferredVariant();
4846                         if ( $pageLang->getCode() !== $variant ) {
4847                                 $pageLang = Language::factory( $variant );
4848                         }
4849
4850                         return $pageLang;
4851                 }
4852
4853                 // @note Can't be cached persistently, depends on user settings.
4854                 // @note ContentHandler::getPageViewLanguage() may need to load the
4855                 //   content to determine the page language!
4856                 $contentHandler = ContentHandler::getForTitle( $this );
4857                 $pageLang = $contentHandler->getPageViewLanguage( $this );
4858                 return $pageLang;
4859         }
4860
4861         /**
4862          * Get a list of rendered edit notices for this page.
4863          *
4864          * Array is keyed by the original message key, and values are rendered using parseAsBlock, so
4865          * they will already be wrapped in paragraphs.
4866          *
4867          * @since 1.21
4868          * @param int $oldid Revision ID that's being edited
4869          * @return array
4870          */
4871         public function getEditNotices( $oldid = 0 ) {
4872                 $notices = [];
4873
4874                 // Optional notice for the entire namespace
4875                 $editnotice_ns = 'editnotice-' . $this->getNamespace();
4876                 $msg = wfMessage( $editnotice_ns );
4877                 if ( $msg->exists() ) {
4878                         $html = $msg->parseAsBlock();
4879                         // Edit notices may have complex logic, but output nothing (T91715)
4880                         if ( trim( $html ) !== '' ) {
4881                                 $notices[$editnotice_ns] = Html::rawElement(
4882                                         'div',
4883                                         [ 'class' => [
4884                                                 'mw-editnotice',
4885                                                 'mw-editnotice-namespace',
4886                                                 Sanitizer::escapeClass( "mw-$editnotice_ns" )
4887                                         ] ],
4888                                         $html
4889                                 );
4890                         }
4891                 }
4892
4893                 if ( MWNamespace::hasSubpages( $this->getNamespace() ) ) {
4894                         // Optional notice for page itself and any parent page
4895                         $parts = explode( '/', $this->getDBkey() );
4896                         $editnotice_base = $editnotice_ns;
4897                         while ( count( $parts ) > 0 ) {
4898                                 $editnotice_base .= '-' . array_shift( $parts );
4899                                 $msg = wfMessage( $editnotice_base );
4900                                 if ( $msg->exists() ) {
4901                                         $html = $msg->parseAsBlock();
4902                                         if ( trim( $html ) !== '' ) {
4903                                                 $notices[$editnotice_base] = Html::rawElement(
4904                                                         'div',
4905                                                         [ 'class' => [
4906                                                                 'mw-editnotice',
4907                                                                 'mw-editnotice-base',
4908                                                                 Sanitizer::escapeClass( "mw-$editnotice_base" )
4909                                                         ] ],
4910                                                         $html
4911                                                 );
4912                                         }
4913                                 }
4914                         }
4915                 } else {
4916                         // Even if there are no subpages in namespace, we still don't want "/" in MediaWiki message keys
4917                         $editnoticeText = $editnotice_ns . '-' . strtr( $this->getDBkey(), '/', '-' );
4918                         $msg = wfMessage( $editnoticeText );
4919                         if ( $msg->exists() ) {
4920                                 $html = $msg->parseAsBlock();
4921                                 if ( trim( $html ) !== '' ) {
4922                                         $notices[$editnoticeText] = Html::rawElement(
4923                                                 'div',
4924                                                 [ 'class' => [
4925                                                         'mw-editnotice',
4926                                                         'mw-editnotice-page',
4927                                                         Sanitizer::escapeClass( "mw-$editnoticeText" )
4928                                                 ] ],
4929                                                 $html
4930                                         );
4931                                 }
4932                         }
4933                 }
4934
4935                 Hooks::run( 'TitleGetEditNotices', [ $this, $oldid, &$notices ] );
4936                 return $notices;
4937         }
4938
4939         /**
4940          * @return array
4941          */
4942         public function __sleep() {
4943                 return [
4944                         'mNamespace',
4945                         'mDbkeyform',
4946                         'mFragment',
4947                         'mInterwiki',
4948                         'mLocalInterwiki',
4949                         'mUserCaseDBKey',
4950                         'mDefaultNamespace',
4951                 ];
4952         }
4953
4954         public function __wakeup() {
4955                 $this->mArticleID = ( $this->mNamespace >= 0 ) ? -1 : 0;
4956                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
4957                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
4958         }
4959
4960 }