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() ), $this->getDBkey() );
1319         }
1320
1321         /**
1322          * Get a Title object associated with the talk page of this article,
1323          * if such a talk page can exist.
1324          *
1325          * @since 1.30
1326          *
1327          * @return Title The object for the talk page,
1328          *         or null if no associated talk page can exist, according to canHaveTalkPage().
1329          */
1330         public function getTalkPageIfDefined() {
1331                 if ( !$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
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                         return $this->getTalkPage();
1369                 }
1370         }
1371
1372         /**
1373          * Get the default namespace index, for when there is no namespace
1374          *
1375          * @return int Default namespace index
1376          */
1377         public function getDefaultNamespace() {
1378                 return $this->mDefaultNamespace;
1379         }
1380
1381         /**
1382          * Get the Title fragment (i.e.\ the bit after the #) in text form
1383          *
1384          * Use Title::hasFragment to check for a fragment
1385          *
1386          * @return string Title fragment
1387          */
1388         public function getFragment() {
1389                 return $this->mFragment;
1390         }
1391
1392         /**
1393          * Check if a Title fragment is set
1394          *
1395          * @return bool
1396          * @since 1.23
1397          */
1398         public function hasFragment() {
1399                 return $this->mFragment !== '';
1400         }
1401
1402         /**
1403          * Get the fragment in URL form, including the "#" character if there is one
1404          *
1405          * @return string Fragment in URL form
1406          */
1407         public function getFragmentForURL() {
1408                 if ( !$this->hasFragment() ) {
1409                         return '';
1410                 } elseif ( $this->isExternal() && !$this->getTransWikiID() ) {
1411                         return '#' . Sanitizer::escapeIdForExternalInterwiki( $this->getFragment() );
1412                 }
1413                 return '#' . Sanitizer::escapeIdForLink( $this->getFragment() );
1414         }
1415
1416         /**
1417          * Set the fragment for this title. Removes the first character from the
1418          * specified fragment before setting, so it assumes you're passing it with
1419          * an initial "#".
1420          *
1421          * Deprecated for public use, use Title::makeTitle() with fragment parameter,
1422          * or Title::createFragmentTarget().
1423          * Still in active use privately.
1424          *
1425          * @private
1426          * @param string $fragment Text
1427          */
1428         public function setFragment( $fragment ) {
1429                 $this->mFragment = strtr( substr( $fragment, 1 ), '_', ' ' );
1430         }
1431
1432         /**
1433          * Creates a new Title for a different fragment of the same page.
1434          *
1435          * @since 1.27
1436          * @param string $fragment
1437          * @return Title
1438          */
1439         public function createFragmentTarget( $fragment ) {
1440                 return self::makeTitle(
1441                         $this->getNamespace(),
1442                         $this->getText(),
1443                         $fragment,
1444                         $this->getInterwiki()
1445                 );
1446         }
1447
1448         /**
1449          * Prefix some arbitrary text with the namespace or interwiki prefix
1450          * of this object
1451          *
1452          * @param string $name The text
1453          * @return string The prefixed text
1454          */
1455         private function prefix( $name ) {
1456                 global $wgContLang;
1457
1458                 $p = '';
1459                 if ( $this->isExternal() ) {
1460                         $p = $this->mInterwiki . ':';
1461                 }
1462
1463                 if ( 0 != $this->mNamespace ) {
1464                         $nsText = $this->getNsText();
1465
1466                         if ( $nsText === false ) {
1467                                 // See T165149. Awkward, but better than erroneously linking to the main namespace.
1468                                 $nsText = $wgContLang->getNsText( NS_SPECIAL ) . ":Badtitle/NS{$this->mNamespace}";
1469                         }
1470
1471                         $p .= $nsText . ':';
1472                 }
1473                 return $p . $name;
1474         }
1475
1476         /**
1477          * Get the prefixed database key form
1478          *
1479          * @return string The prefixed title, with underscores and
1480          *  any interwiki and namespace prefixes
1481          */
1482         public function getPrefixedDBkey() {
1483                 $s = $this->prefix( $this->mDbkeyform );
1484                 $s = strtr( $s, ' ', '_' );
1485                 return $s;
1486         }
1487
1488         /**
1489          * Get the prefixed title with spaces.
1490          * This is the form usually used for display
1491          *
1492          * @return string The prefixed title, with spaces
1493          */
1494         public function getPrefixedText() {
1495                 if ( $this->mPrefixedText === null ) {
1496                         $s = $this->prefix( $this->mTextform );
1497                         $s = strtr( $s, '_', ' ' );
1498                         $this->mPrefixedText = $s;
1499                 }
1500                 return $this->mPrefixedText;
1501         }
1502
1503         /**
1504          * Return a string representation of this title
1505          *
1506          * @return string Representation of this title
1507          */
1508         public function __toString() {
1509                 return $this->getPrefixedText();
1510         }
1511
1512         /**
1513          * Get the prefixed title with spaces, plus any fragment
1514          * (part beginning with '#')
1515          *
1516          * @return string The prefixed title, with spaces and the fragment, including '#'
1517          */
1518         public function getFullText() {
1519                 $text = $this->getPrefixedText();
1520                 if ( $this->hasFragment() ) {
1521                         $text .= '#' . $this->getFragment();
1522                 }
1523                 return $text;
1524         }
1525
1526         /**
1527          * Get the root page name text without a namespace, i.e. the leftmost part before any slashes
1528          *
1529          * @par Example:
1530          * @code
1531          * Title::newFromText('User:Foo/Bar/Baz')->getRootText();
1532          * # returns: 'Foo'
1533          * @endcode
1534          *
1535          * @return string Root name
1536          * @since 1.20
1537          */
1538         public function getRootText() {
1539                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1540                         return $this->getText();
1541                 }
1542
1543                 return strtok( $this->getText(), '/' );
1544         }
1545
1546         /**
1547          * Get the root page name title, i.e. the leftmost part before any slashes
1548          *
1549          * @par Example:
1550          * @code
1551          * Title::newFromText('User:Foo/Bar/Baz')->getRootTitle();
1552          * # returns: Title{User:Foo}
1553          * @endcode
1554          *
1555          * @return Title Root title
1556          * @since 1.20
1557          */
1558         public function getRootTitle() {
1559                 return self::makeTitle( $this->getNamespace(), $this->getRootText() );
1560         }
1561
1562         /**
1563          * Get the base page name without a namespace, i.e. the part before the subpage name
1564          *
1565          * @par Example:
1566          * @code
1567          * Title::newFromText('User:Foo/Bar/Baz')->getBaseText();
1568          * # returns: 'Foo/Bar'
1569          * @endcode
1570          *
1571          * @return string Base name
1572          */
1573         public function getBaseText() {
1574                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1575                         return $this->getText();
1576                 }
1577
1578                 $parts = explode( '/', $this->getText() );
1579                 # Don't discard the real title if there's no subpage involved
1580                 if ( count( $parts ) > 1 ) {
1581                         unset( $parts[count( $parts ) - 1] );
1582                 }
1583                 return implode( '/', $parts );
1584         }
1585
1586         /**
1587          * Get the base page name title, i.e. the part before the subpage name
1588          *
1589          * @par Example:
1590          * @code
1591          * Title::newFromText('User:Foo/Bar/Baz')->getBaseTitle();
1592          * # returns: Title{User:Foo/Bar}
1593          * @endcode
1594          *
1595          * @return Title Base title
1596          * @since 1.20
1597          */
1598         public function getBaseTitle() {
1599                 return self::makeTitle( $this->getNamespace(), $this->getBaseText() );
1600         }
1601
1602         /**
1603          * Get the lowest-level subpage name, i.e. the rightmost part after any slashes
1604          *
1605          * @par Example:
1606          * @code
1607          * Title::newFromText('User:Foo/Bar/Baz')->getSubpageText();
1608          * # returns: "Baz"
1609          * @endcode
1610          *
1611          * @return string Subpage name
1612          */
1613         public function getSubpageText() {
1614                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1615                         return $this->mTextform;
1616                 }
1617                 $parts = explode( '/', $this->mTextform );
1618                 return $parts[count( $parts ) - 1];
1619         }
1620
1621         /**
1622          * Get the title for a subpage of the current page
1623          *
1624          * @par Example:
1625          * @code
1626          * Title::newFromText('User:Foo/Bar/Baz')->getSubpage("Asdf");
1627          * # returns: Title{User:Foo/Bar/Baz/Asdf}
1628          * @endcode
1629          *
1630          * @param string $text The subpage name to add to the title
1631          * @return Title Subpage title
1632          * @since 1.20
1633          */
1634         public function getSubpage( $text ) {
1635                 return self::makeTitleSafe( $this->getNamespace(), $this->getText() . '/' . $text );
1636         }
1637
1638         /**
1639          * Get a URL-encoded form of the subpage text
1640          *
1641          * @return string URL-encoded subpage name
1642          */
1643         public function getSubpageUrlForm() {
1644                 $text = $this->getSubpageText();
1645                 $text = wfUrlencode( strtr( $text, ' ', '_' ) );
1646                 return $text;
1647         }
1648
1649         /**
1650          * Get a URL-encoded title (not an actual URL) including interwiki
1651          *
1652          * @return string The URL-encoded form
1653          */
1654         public function getPrefixedURL() {
1655                 $s = $this->prefix( $this->mDbkeyform );
1656                 $s = wfUrlencode( strtr( $s, ' ', '_' ) );
1657                 return $s;
1658         }
1659
1660         /**
1661          * Helper to fix up the get{Canonical,Full,Link,Local,Internal}URL args
1662          * get{Canonical,Full,Link,Local,Internal}URL methods accepted an optional
1663          * second argument named variant. This was deprecated in favor
1664          * of passing an array of option with a "variant" key
1665          * Once $query2 is removed for good, this helper can be dropped
1666          * and the wfArrayToCgi moved to getLocalURL();
1667          *
1668          * @since 1.19 (r105919)
1669          * @param array|string $query
1670          * @param string|string[]|bool $query2
1671          * @return string
1672          */
1673         private static function fixUrlQueryArgs( $query, $query2 = false ) {
1674                 if ( $query2 !== false ) {
1675                         wfDeprecated( "Title::get{Canonical,Full,Link,Local,Internal}URL " .
1676                                 "method called with a second parameter is deprecated. Add your " .
1677                                 "parameter to an array passed as the first parameter.", "1.19" );
1678                 }
1679                 if ( is_array( $query ) ) {
1680                         $query = wfArrayToCgi( $query );
1681                 }
1682                 if ( $query2 ) {
1683                         if ( is_string( $query2 ) ) {
1684                                 // $query2 is a string, we will consider this to be
1685                                 // a deprecated $variant argument and add it to the query
1686                                 $query2 = wfArrayToCgi( [ 'variant' => $query2 ] );
1687                         } else {
1688                                 $query2 = wfArrayToCgi( $query2 );
1689                         }
1690                         // If we have $query content add a & to it first
1691                         if ( $query ) {
1692                                 $query .= '&';
1693                         }
1694                         // Now append the queries together
1695                         $query .= $query2;
1696                 }
1697                 return $query;
1698         }
1699
1700         /**
1701          * Get a real URL referring to this title, with interwiki link and
1702          * fragment
1703          *
1704          * @see self::getLocalURL for the arguments.
1705          * @see wfExpandUrl
1706          * @param string|string[] $query
1707          * @param string|string[]|bool $query2
1708          * @param string $proto Protocol type to use in URL
1709          * @return string The URL
1710          */
1711         public function getFullURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1712                 $query = self::fixUrlQueryArgs( $query, $query2 );
1713
1714                 # Hand off all the decisions on urls to getLocalURL
1715                 $url = $this->getLocalURL( $query );
1716
1717                 # Expand the url to make it a full url. Note that getLocalURL has the
1718                 # potential to output full urls for a variety of reasons, so we use
1719                 # wfExpandUrl instead of simply prepending $wgServer
1720                 $url = wfExpandUrl( $url, $proto );
1721
1722                 # Finally, add the fragment.
1723                 $url .= $this->getFragmentForURL();
1724                 // Avoid PHP 7.1 warning from passing $this by reference
1725                 $titleRef = $this;
1726                 Hooks::run( 'GetFullURL', [ &$titleRef, &$url, $query ] );
1727                 return $url;
1728         }
1729
1730         /**
1731          * Get a url appropriate for making redirects based on an untrusted url arg
1732          *
1733          * This is basically the same as getFullUrl(), but in the case of external
1734          * interwikis, we send the user to a landing page, to prevent possible
1735          * phishing attacks and the like.
1736          *
1737          * @note Uses current protocol by default, since technically relative urls
1738          *   aren't allowed in redirects per HTTP spec, so this is not suitable for
1739          *   places where the url gets cached, as might pollute between
1740          *   https and non-https users.
1741          * @see self::getLocalURL for the arguments.
1742          * @param array|string $query
1743          * @param string $proto Protocol type to use in URL
1744          * @return String. A url suitable to use in an HTTP location header.
1745          */
1746         public function getFullUrlForRedirect( $query = '', $proto = PROTO_CURRENT ) {
1747                 $target = $this;
1748                 if ( $this->isExternal() ) {
1749                         $target = SpecialPage::getTitleFor(
1750                                 'GoToInterwiki',
1751                                 $this->getPrefixedDBKey()
1752                         );
1753                 }
1754                 return $target->getFullUrl( $query, false, $proto );
1755         }
1756
1757         /**
1758          * Get a URL with no fragment or server name (relative URL) from a Title object.
1759          * If this page is generated with action=render, however,
1760          * $wgServer is prepended to make an absolute URL.
1761          *
1762          * @see self::getFullURL to always get an absolute URL.
1763          * @see self::getLinkURL to always get a URL that's the simplest URL that will be
1764          *  valid to link, locally, to the current Title.
1765          * @see self::newFromText to produce a Title object.
1766          *
1767          * @param string|string[] $query An optional query string,
1768          *   not used for interwiki links. Can be specified as an associative array as well,
1769          *   e.g., array( 'action' => 'edit' ) (keys and values will be URL-escaped).
1770          *   Some query patterns will trigger various shorturl path replacements.
1771          * @param string|string[]|bool $query2 An optional secondary query array. This one MUST
1772          *   be an array. If a string is passed it will be interpreted as a deprecated
1773          *   variant argument and urlencoded into a variant= argument.
1774          *   This second query argument will be added to the $query
1775          *   The second parameter is deprecated since 1.19. Pass it as a key,value
1776          *   pair in the first parameter array instead.
1777          *
1778          * @return string String of the URL.
1779          */
1780         public function getLocalURL( $query = '', $query2 = false ) {
1781                 global $wgArticlePath, $wgScript, $wgServer, $wgRequest;
1782
1783                 $query = self::fixUrlQueryArgs( $query, $query2 );
1784
1785                 $interwiki = self::getInterwikiLookup()->fetch( $this->mInterwiki );
1786                 if ( $interwiki ) {
1787                         $namespace = $this->getNsText();
1788                         if ( $namespace != '' ) {
1789                                 # Can this actually happen? Interwikis shouldn't be parsed.
1790                                 # Yes! It can in interwiki transclusion. But... it probably shouldn't.
1791                                 $namespace .= ':';
1792                         }
1793                         $url = $interwiki->getURL( $namespace . $this->getDBkey() );
1794                         $url = wfAppendQuery( $url, $query );
1795                 } else {
1796                         $dbkey = wfUrlencode( $this->getPrefixedDBkey() );
1797                         if ( $query == '' ) {
1798                                 $url = str_replace( '$1', $dbkey, $wgArticlePath );
1799                                 // Avoid PHP 7.1 warning from passing $this by reference
1800                                 $titleRef = $this;
1801                                 Hooks::run( 'GetLocalURL::Article', [ &$titleRef, &$url ] );
1802                         } else {
1803                                 global $wgVariantArticlePath, $wgActionPaths, $wgContLang;
1804                                 $url = false;
1805                                 $matches = [];
1806
1807                                 if ( !empty( $wgActionPaths )
1808                                         && preg_match( '/^(.*&|)action=([^&]*)(&(.*)|)$/', $query, $matches )
1809                                 ) {
1810                                         $action = urldecode( $matches[2] );
1811                                         if ( isset( $wgActionPaths[$action] ) ) {
1812                                                 $query = $matches[1];
1813                                                 if ( isset( $matches[4] ) ) {
1814                                                         $query .= $matches[4];
1815                                                 }
1816                                                 $url = str_replace( '$1', $dbkey, $wgActionPaths[$action] );
1817                                                 if ( $query != '' ) {
1818                                                         $url = wfAppendQuery( $url, $query );
1819                                                 }
1820                                         }
1821                                 }
1822
1823                                 if ( $url === false
1824                                         && $wgVariantArticlePath
1825                                         && preg_match( '/^variant=([^&]*)$/', $query, $matches )
1826                                         && $this->getPageLanguage()->equals( $wgContLang )
1827                                         && $this->getPageLanguage()->hasVariants()
1828                                 ) {
1829                                         $variant = urldecode( $matches[1] );
1830                                         if ( $this->getPageLanguage()->hasVariant( $variant ) ) {
1831                                                 // Only do the variant replacement if the given variant is a valid
1832                                                 // variant for the page's language.
1833                                                 $url = str_replace( '$2', urlencode( $variant ), $wgVariantArticlePath );
1834                                                 $url = str_replace( '$1', $dbkey, $url );
1835                                         }
1836                                 }
1837
1838                                 if ( $url === false ) {
1839                                         if ( $query == '-' ) {
1840                                                 $query = '';
1841                                         }
1842                                         $url = "{$wgScript}?title={$dbkey}&{$query}";
1843                                 }
1844                         }
1845                         // Avoid PHP 7.1 warning from passing $this by reference
1846                         $titleRef = $this;
1847                         Hooks::run( 'GetLocalURL::Internal', [ &$titleRef, &$url, $query ] );
1848
1849                         // @todo FIXME: This causes breakage in various places when we
1850                         // actually expected a local URL and end up with dupe prefixes.
1851                         if ( $wgRequest->getVal( 'action' ) == 'render' ) {
1852                                 $url = $wgServer . $url;
1853                         }
1854                 }
1855                 // Avoid PHP 7.1 warning from passing $this by reference
1856                 $titleRef = $this;
1857                 Hooks::run( 'GetLocalURL', [ &$titleRef, &$url, $query ] );
1858                 return $url;
1859         }
1860
1861         /**
1862          * Get a URL that's the simplest URL that will be valid to link, locally,
1863          * to the current Title.  It includes the fragment, but does not include
1864          * the server unless action=render is used (or the link is external).  If
1865          * there's a fragment but the prefixed text is empty, we just return a link
1866          * to the fragment.
1867          *
1868          * The result obviously should not be URL-escaped, but does need to be
1869          * HTML-escaped if it's being output in HTML.
1870          *
1871          * @param string|string[] $query
1872          * @param bool $query2
1873          * @param string|int|bool $proto A PROTO_* constant on how the URL should be expanded,
1874          *                               or false (default) for no expansion
1875          * @see self::getLocalURL for the arguments.
1876          * @return string The URL
1877          */
1878         public function getLinkURL( $query = '', $query2 = false, $proto = false ) {
1879                 if ( $this->isExternal() || $proto !== false ) {
1880                         $ret = $this->getFullURL( $query, $query2, $proto );
1881                 } elseif ( $this->getPrefixedText() === '' && $this->hasFragment() ) {
1882                         $ret = $this->getFragmentForURL();
1883                 } else {
1884                         $ret = $this->getLocalURL( $query, $query2 ) . $this->getFragmentForURL();
1885                 }
1886                 return $ret;
1887         }
1888
1889         /**
1890          * Get the URL form for an internal link.
1891          * - Used in various CDN-related code, in case we have a different
1892          * internal hostname for the server from the exposed one.
1893          *
1894          * This uses $wgInternalServer to qualify the path, or $wgServer
1895          * if $wgInternalServer is not set. If the server variable used is
1896          * protocol-relative, the URL will be expanded to http://
1897          *
1898          * @see self::getLocalURL for the arguments.
1899          * @return string The URL
1900          */
1901         public function getInternalURL( $query = '', $query2 = false ) {
1902                 global $wgInternalServer, $wgServer;
1903                 $query = self::fixUrlQueryArgs( $query, $query2 );
1904                 $server = $wgInternalServer !== false ? $wgInternalServer : $wgServer;
1905                 $url = wfExpandUrl( $server . $this->getLocalURL( $query ), PROTO_HTTP );
1906                 // Avoid PHP 7.1 warning from passing $this by reference
1907                 $titleRef = $this;
1908                 Hooks::run( 'GetInternalURL', [ &$titleRef, &$url, $query ] );
1909                 return $url;
1910         }
1911
1912         /**
1913          * Get the URL for a canonical link, for use in things like IRC and
1914          * e-mail notifications. Uses $wgCanonicalServer and the
1915          * GetCanonicalURL hook.
1916          *
1917          * NOTE: Unlike getInternalURL(), the canonical URL includes the fragment
1918          *
1919          * @see self::getLocalURL for the arguments.
1920          * @return string The URL
1921          * @since 1.18
1922          */
1923         public function getCanonicalURL( $query = '', $query2 = false ) {
1924                 $query = self::fixUrlQueryArgs( $query, $query2 );
1925                 $url = wfExpandUrl( $this->getLocalURL( $query ) . $this->getFragmentForURL(), PROTO_CANONICAL );
1926                 // Avoid PHP 7.1 warning from passing $this by reference
1927                 $titleRef = $this;
1928                 Hooks::run( 'GetCanonicalURL', [ &$titleRef, &$url, $query ] );
1929                 return $url;
1930         }
1931
1932         /**
1933          * Get the edit URL for this Title
1934          *
1935          * @return string The URL, or a null string if this is an interwiki link
1936          */
1937         public function getEditURL() {
1938                 if ( $this->isExternal() ) {
1939                         return '';
1940                 }
1941                 $s = $this->getLocalURL( 'action=edit' );
1942
1943                 return $s;
1944         }
1945
1946         /**
1947          * Can $user perform $action on this page?
1948          * This skips potentially expensive cascading permission checks
1949          * as well as avoids expensive error formatting
1950          *
1951          * Suitable for use for nonessential UI controls in common cases, but
1952          * _not_ for functional access control.
1953          *
1954          * May provide false positives, but should never provide a false negative.
1955          *
1956          * @param string $action Action that permission needs to be checked for
1957          * @param User $user User to check (since 1.19); $wgUser will be used if not provided.
1958          * @return bool
1959          */
1960         public function quickUserCan( $action, $user = null ) {
1961                 return $this->userCan( $action, $user, false );
1962         }
1963
1964         /**
1965          * Can $user perform $action on this page?
1966          *
1967          * @param string $action Action that permission needs to be checked for
1968          * @param User $user User to check (since 1.19); $wgUser will be used if not
1969          *   provided.
1970          * @param string $rigor Same format as Title::getUserPermissionsErrors()
1971          * @return bool
1972          */
1973         public function userCan( $action, $user = null, $rigor = 'secure' ) {
1974                 if ( !$user instanceof User ) {
1975                         global $wgUser;
1976                         $user = $wgUser;
1977                 }
1978
1979                 return !count( $this->getUserPermissionsErrorsInternal( $action, $user, $rigor, true ) );
1980         }
1981
1982         /**
1983          * Can $user perform $action on this page?
1984          *
1985          * @todo FIXME: This *does not* check throttles (User::pingLimiter()).
1986          *
1987          * @param string $action Action that permission needs to be checked for
1988          * @param User $user User to check
1989          * @param string $rigor One of (quick,full,secure)
1990          *   - quick  : does cheap permission checks from replica DBs (usable for GUI creation)
1991          *   - full   : does cheap and expensive checks possibly from a replica DB
1992          *   - secure : does cheap and expensive checks, using the master as needed
1993          * @param array $ignoreErrors Array of Strings Set this to a list of message keys
1994          *   whose corresponding errors may be ignored.
1995          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
1996          */
1997         public function getUserPermissionsErrors(
1998                 $action, $user, $rigor = 'secure', $ignoreErrors = []
1999         ) {
2000                 $errors = $this->getUserPermissionsErrorsInternal( $action, $user, $rigor );
2001
2002                 // Remove the errors being ignored.
2003                 foreach ( $errors as $index => $error ) {
2004                         $errKey = is_array( $error ) ? $error[0] : $error;
2005
2006                         if ( in_array( $errKey, $ignoreErrors ) ) {
2007                                 unset( $errors[$index] );
2008                         }
2009                         if ( $errKey instanceof MessageSpecifier && in_array( $errKey->getKey(), $ignoreErrors ) ) {
2010                                 unset( $errors[$index] );
2011                         }
2012                 }
2013
2014                 return $errors;
2015         }
2016
2017         /**
2018          * Permissions checks that fail most often, and which are easiest to test.
2019          *
2020          * @param string $action The action to check
2021          * @param User $user User to check
2022          * @param array $errors List of current errors
2023          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2024          * @param bool $short Short circuit on first error
2025          *
2026          * @return array List of errors
2027          */
2028         private function checkQuickPermissions( $action, $user, $errors, $rigor, $short ) {
2029                 if ( !Hooks::run( 'TitleQuickPermissions',
2030                         [ $this, $user, $action, &$errors, ( $rigor !== 'quick' ), $short ] )
2031                 ) {
2032                         return $errors;
2033                 }
2034
2035                 if ( $action == 'create' ) {
2036                         if (
2037                                 ( $this->isTalkPage() && !$user->isAllowed( 'createtalk' ) ) ||
2038                                 ( !$this->isTalkPage() && !$user->isAllowed( 'createpage' ) )
2039                         ) {
2040                                 $errors[] = $user->isAnon() ? [ 'nocreatetext' ] : [ 'nocreate-loggedin' ];
2041                         }
2042                 } elseif ( $action == 'move' ) {
2043                         if ( !$user->isAllowed( 'move-rootuserpages' )
2044                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
2045                                 // Show user page-specific message only if the user can move other pages
2046                                 $errors[] = [ 'cant-move-user-page' ];
2047                         }
2048
2049                         // Check if user is allowed to move files if it's a file
2050                         if ( $this->mNamespace == NS_FILE && !$user->isAllowed( 'movefile' ) ) {
2051                                 $errors[] = [ 'movenotallowedfile' ];
2052                         }
2053
2054                         // Check if user is allowed to move category pages if it's a category page
2055                         if ( $this->mNamespace == NS_CATEGORY && !$user->isAllowed( 'move-categorypages' ) ) {
2056                                 $errors[] = [ 'cant-move-category-page' ];
2057                         }
2058
2059                         if ( !$user->isAllowed( 'move' ) ) {
2060                                 // User can't move anything
2061                                 $userCanMove = User::groupHasPermission( 'user', 'move' );
2062                                 $autoconfirmedCanMove = User::groupHasPermission( 'autoconfirmed', 'move' );
2063                                 if ( $user->isAnon() && ( $userCanMove || $autoconfirmedCanMove ) ) {
2064                                         // custom message if logged-in users without any special rights can move
2065                                         $errors[] = [ 'movenologintext' ];
2066                                 } else {
2067                                         $errors[] = [ 'movenotallowed' ];
2068                                 }
2069                         }
2070                 } elseif ( $action == 'move-target' ) {
2071                         if ( !$user->isAllowed( 'move' ) ) {
2072                                 // User can't move anything
2073                                 $errors[] = [ 'movenotallowed' ];
2074                         } elseif ( !$user->isAllowed( 'move-rootuserpages' )
2075                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
2076                                 // Show user page-specific message only if the user can move other pages
2077                                 $errors[] = [ 'cant-move-to-user-page' ];
2078                         } elseif ( !$user->isAllowed( 'move-categorypages' )
2079                                         && $this->mNamespace == NS_CATEGORY ) {
2080                                 // Show category page-specific message only if the user can move other pages
2081                                 $errors[] = [ 'cant-move-to-category-page' ];
2082                         }
2083                 } elseif ( !$user->isAllowed( $action ) ) {
2084                         $errors[] = $this->missingPermissionError( $action, $short );
2085                 }
2086
2087                 return $errors;
2088         }
2089
2090         /**
2091          * Add the resulting error code to the errors array
2092          *
2093          * @param array $errors List of current errors
2094          * @param array $result Result of errors
2095          *
2096          * @return array List of errors
2097          */
2098         private function resultToError( $errors, $result ) {
2099                 if ( is_array( $result ) && count( $result ) && !is_array( $result[0] ) ) {
2100                         // A single array representing an error
2101                         $errors[] = $result;
2102                 } elseif ( is_array( $result ) && is_array( $result[0] ) ) {
2103                         // A nested array representing multiple errors
2104                         $errors = array_merge( $errors, $result );
2105                 } elseif ( $result !== '' && is_string( $result ) ) {
2106                         // A string representing a message-id
2107                         $errors[] = [ $result ];
2108                 } elseif ( $result instanceof MessageSpecifier ) {
2109                         // A message specifier representing an error
2110                         $errors[] = [ $result ];
2111                 } elseif ( $result === false ) {
2112                         // a generic "We don't want them to do that"
2113                         $errors[] = [ 'badaccess-group0' ];
2114                 }
2115                 return $errors;
2116         }
2117
2118         /**
2119          * Check various permission hooks
2120          *
2121          * @param string $action The action to check
2122          * @param User $user User to check
2123          * @param array $errors List of current errors
2124          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2125          * @param bool $short Short circuit on first error
2126          *
2127          * @return array List of errors
2128          */
2129         private function checkPermissionHooks( $action, $user, $errors, $rigor, $short ) {
2130                 // Use getUserPermissionsErrors instead
2131                 $result = '';
2132                 // Avoid PHP 7.1 warning from passing $this by reference
2133                 $titleRef = $this;
2134                 if ( !Hooks::run( 'userCan', [ &$titleRef, &$user, $action, &$result ] ) ) {
2135                         return $result ? [] : [ [ 'badaccess-group0' ] ];
2136                 }
2137                 // Check getUserPermissionsErrors hook
2138                 // Avoid PHP 7.1 warning from passing $this by reference
2139                 $titleRef = $this;
2140                 if ( !Hooks::run( 'getUserPermissionsErrors', [ &$titleRef, &$user, $action, &$result ] ) ) {
2141                         $errors = $this->resultToError( $errors, $result );
2142                 }
2143                 // Check getUserPermissionsErrorsExpensive hook
2144                 if (
2145                         $rigor !== 'quick'
2146                         && !( $short && count( $errors ) > 0 )
2147                         && !Hooks::run( 'getUserPermissionsErrorsExpensive', [ &$titleRef, &$user, $action, &$result ] )
2148                 ) {
2149                         $errors = $this->resultToError( $errors, $result );
2150                 }
2151
2152                 return $errors;
2153         }
2154
2155         /**
2156          * Check permissions on special pages & namespaces
2157          *
2158          * @param string $action The action to check
2159          * @param User $user User to check
2160          * @param array $errors List of current errors
2161          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2162          * @param bool $short Short circuit on first error
2163          *
2164          * @return array List of errors
2165          */
2166         private function checkSpecialsAndNSPermissions( $action, $user, $errors, $rigor, $short ) {
2167                 # Only 'createaccount' can be performed on special pages,
2168                 # which don't actually exist in the DB.
2169                 if ( $this->isSpecialPage() && $action !== 'createaccount' ) {
2170                         $errors[] = [ 'ns-specialprotected' ];
2171                 }
2172
2173                 # Check $wgNamespaceProtection for restricted namespaces
2174                 if ( $this->isNamespaceProtected( $user ) ) {
2175                         $ns = $this->mNamespace == NS_MAIN ?
2176                                 wfMessage( 'nstab-main' )->text() : $this->getNsText();
2177                         $errors[] = $this->mNamespace == NS_MEDIAWIKI ?
2178                                 [ 'protectedinterface', $action ] : [ 'namespaceprotected', $ns, $action ];
2179                 }
2180
2181                 return $errors;
2182         }
2183
2184         /**
2185          * Check CSS/JS sub-page permissions
2186          *
2187          * @param string $action The action to check
2188          * @param User $user User to check
2189          * @param array $errors List of current errors
2190          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2191          * @param bool $short Short circuit on first error
2192          *
2193          * @return array List of errors
2194          */
2195         private function checkCSSandJSPermissions( $action, $user, $errors, $rigor, $short ) {
2196                 # Protect css/js subpages of user pages
2197                 # XXX: this might be better using restrictions
2198                 if ( $action != 'patrol' ) {
2199                         if ( preg_match( '/^' . preg_quote( $user->getName(), '/' ) . '\//', $this->mTextform ) ) {
2200                                 if ( $this->isCssSubpage() && !$user->isAllowedAny( 'editmyusercss', 'editusercss' ) ) {
2201                                         $errors[] = [ 'mycustomcssprotected', $action ];
2202                                 } elseif ( $this->isJsSubpage() && !$user->isAllowedAny( 'editmyuserjs', 'edituserjs' ) ) {
2203                                         $errors[] = [ 'mycustomjsprotected', $action ];
2204                                 }
2205                         } else {
2206                                 if ( $this->isCssSubpage() && !$user->isAllowed( 'editusercss' ) ) {
2207                                         $errors[] = [ 'customcssprotected', $action ];
2208                                 } elseif ( $this->isJsSubpage() && !$user->isAllowed( 'edituserjs' ) ) {
2209                                         $errors[] = [ 'customjsprotected', $action ];
2210                                 }
2211                         }
2212                 }
2213
2214                 return $errors;
2215         }
2216
2217         /**
2218          * Check against page_restrictions table requirements on this
2219          * page. The user must possess all required rights for this
2220          * action.
2221          *
2222          * @param string $action The action to check
2223          * @param User $user User to check
2224          * @param array $errors List of current errors
2225          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2226          * @param bool $short Short circuit on first error
2227          *
2228          * @return array List of errors
2229          */
2230         private function checkPageRestrictions( $action, $user, $errors, $rigor, $short ) {
2231                 foreach ( $this->getRestrictions( $action ) as $right ) {
2232                         // Backwards compatibility, rewrite sysop -> editprotected
2233                         if ( $right == 'sysop' ) {
2234                                 $right = 'editprotected';
2235                         }
2236                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2237                         if ( $right == 'autoconfirmed' ) {
2238                                 $right = 'editsemiprotected';
2239                         }
2240                         if ( $right == '' ) {
2241                                 continue;
2242                         }
2243                         if ( !$user->isAllowed( $right ) ) {
2244                                 $errors[] = [ 'protectedpagetext', $right, $action ];
2245                         } elseif ( $this->mCascadeRestriction && !$user->isAllowed( 'protect' ) ) {
2246                                 $errors[] = [ 'protectedpagetext', 'protect', $action ];
2247                         }
2248                 }
2249
2250                 return $errors;
2251         }
2252
2253         /**
2254          * Check restrictions on cascading pages.
2255          *
2256          * @param string $action The action to check
2257          * @param User $user User to check
2258          * @param array $errors List of current errors
2259          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2260          * @param bool $short Short circuit on first error
2261          *
2262          * @return array List of errors
2263          */
2264         private function checkCascadingSourcesRestrictions( $action, $user, $errors, $rigor, $short ) {
2265                 if ( $rigor !== 'quick' && !$this->isCssJsSubpage() ) {
2266                         # We /could/ use the protection level on the source page, but it's
2267                         # fairly ugly as we have to establish a precedence hierarchy for pages
2268                         # included by multiple cascade-protected pages. So just restrict
2269                         # it to people with 'protect' permission, as they could remove the
2270                         # protection anyway.
2271                         list( $cascadingSources, $restrictions ) = $this->getCascadeProtectionSources();
2272                         # Cascading protection depends on more than this page...
2273                         # Several cascading protected pages may include this page...
2274                         # Check each cascading level
2275                         # This is only for protection restrictions, not for all actions
2276                         if ( isset( $restrictions[$action] ) ) {
2277                                 foreach ( $restrictions[$action] as $right ) {
2278                                         // Backwards compatibility, rewrite sysop -> editprotected
2279                                         if ( $right == 'sysop' ) {
2280                                                 $right = 'editprotected';
2281                                         }
2282                                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2283                                         if ( $right == 'autoconfirmed' ) {
2284                                                 $right = 'editsemiprotected';
2285                                         }
2286                                         if ( $right != '' && !$user->isAllowedAll( 'protect', $right ) ) {
2287                                                 $pages = '';
2288                                                 foreach ( $cascadingSources as $page ) {
2289                                                         $pages .= '* [[:' . $page->getPrefixedText() . "]]\n";
2290                                                 }
2291                                                 $errors[] = [ 'cascadeprotected', count( $cascadingSources ), $pages, $action ];
2292                                         }
2293                                 }
2294                         }
2295                 }
2296
2297                 return $errors;
2298         }
2299
2300         /**
2301          * Check action permissions not already checked in checkQuickPermissions
2302          *
2303          * @param string $action The action to check
2304          * @param User $user User to check
2305          * @param array $errors List of current errors
2306          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2307          * @param bool $short Short circuit on first error
2308          *
2309          * @return array List of errors
2310          */
2311         private function checkActionPermissions( $action, $user, $errors, $rigor, $short ) {
2312                 global $wgDeleteRevisionsLimit, $wgLang;
2313
2314                 if ( $action == 'protect' ) {
2315                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit', $user, $rigor, true ) ) ) {
2316                                 // If they can't edit, they shouldn't protect.
2317                                 $errors[] = [ 'protect-cantedit' ];
2318                         }
2319                 } elseif ( $action == 'create' ) {
2320                         $title_protection = $this->getTitleProtection();
2321                         if ( $title_protection ) {
2322                                 if ( $title_protection['permission'] == ''
2323                                         || !$user->isAllowed( $title_protection['permission'] )
2324                                 ) {
2325                                         $errors[] = [
2326                                                 'titleprotected',
2327                                                 User::whoIs( $title_protection['user'] ),
2328                                                 $title_protection['reason']
2329                                         ];
2330                                 }
2331                         }
2332                 } elseif ( $action == 'move' ) {
2333                         // Check for immobile pages
2334                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2335                                 // Specific message for this case
2336                                 $errors[] = [ 'immobile-source-namespace', $this->getNsText() ];
2337                         } elseif ( !$this->isMovable() ) {
2338                                 // Less specific message for rarer cases
2339                                 $errors[] = [ 'immobile-source-page' ];
2340                         }
2341                 } elseif ( $action == 'move-target' ) {
2342                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2343                                 $errors[] = [ 'immobile-target-namespace', $this->getNsText() ];
2344                         } elseif ( !$this->isMovable() ) {
2345                                 $errors[] = [ 'immobile-target-page' ];
2346                         }
2347                 } elseif ( $action == 'delete' ) {
2348                         $tempErrors = $this->checkPageRestrictions( 'edit', $user, [], $rigor, true );
2349                         if ( !$tempErrors ) {
2350                                 $tempErrors = $this->checkCascadingSourcesRestrictions( 'edit',
2351                                         $user, $tempErrors, $rigor, true );
2352                         }
2353                         if ( $tempErrors ) {
2354                                 // If protection keeps them from editing, they shouldn't be able to delete.
2355                                 $errors[] = [ 'deleteprotected' ];
2356                         }
2357                         if ( $rigor !== 'quick' && $wgDeleteRevisionsLimit
2358                                 && !$this->userCan( 'bigdelete', $user ) && $this->isBigDeletion()
2359                         ) {
2360                                 $errors[] = [ 'delete-toobig', $wgLang->formatNum( $wgDeleteRevisionsLimit ) ];
2361                         }
2362                 } elseif ( $action === 'undelete' ) {
2363                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit', $user, $rigor, true ) ) ) {
2364                                 // Undeleting implies editing
2365                                 $errors[] = [ 'undelete-cantedit' ];
2366                         }
2367                         if ( !$this->exists()
2368                                 && count( $this->getUserPermissionsErrorsInternal( 'create', $user, $rigor, true ) )
2369                         ) {
2370                                 // Undeleting where nothing currently exists implies creating
2371                                 $errors[] = [ 'undelete-cantcreate' ];
2372                         }
2373                 }
2374                 return $errors;
2375         }
2376
2377         /**
2378          * Check that the user isn't blocked from editing.
2379          *
2380          * @param string $action The action to check
2381          * @param User $user User to check
2382          * @param array $errors List of current errors
2383          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2384          * @param bool $short Short circuit on first error
2385          *
2386          * @return array List of errors
2387          */
2388         private function checkUserBlock( $action, $user, $errors, $rigor, $short ) {
2389                 global $wgEmailConfirmToEdit, $wgBlockDisablesLogin;
2390                 // Account creation blocks handled at userlogin.
2391                 // Unblocking handled in SpecialUnblock
2392                 if ( $rigor === 'quick' || in_array( $action, [ 'createaccount', 'unblock' ] ) ) {
2393                         return $errors;
2394                 }
2395
2396                 // Optimize for a very common case
2397                 if ( $action === 'read' && !$wgBlockDisablesLogin ) {
2398                         return $errors;
2399                 }
2400
2401                 if ( $wgEmailConfirmToEdit && !$user->isEmailConfirmed() ) {
2402                         $errors[] = [ 'confirmedittext' ];
2403                 }
2404
2405                 $useSlave = ( $rigor !== 'secure' );
2406                 if ( ( $action == 'edit' || $action == 'create' )
2407                         && !$user->isBlockedFrom( $this, $useSlave )
2408                 ) {
2409                         // Don't block the user from editing their own talk page unless they've been
2410                         // explicitly blocked from that too.
2411                 } elseif ( $user->isBlocked() && $user->getBlock()->prevents( $action ) !== false ) {
2412                         // @todo FIXME: Pass the relevant context into this function.
2413                         $errors[] = $user->getBlock()->getPermissionsError( RequestContext::getMain() );
2414                 }
2415
2416                 return $errors;
2417         }
2418
2419         /**
2420          * Check that the user is allowed to read this page.
2421          *
2422          * @param string $action The action to check
2423          * @param User $user User to check
2424          * @param array $errors List of current errors
2425          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2426          * @param bool $short Short circuit on first error
2427          *
2428          * @return array List of errors
2429          */
2430         private function checkReadPermissions( $action, $user, $errors, $rigor, $short ) {
2431                 global $wgWhitelistRead, $wgWhitelistReadRegexp;
2432
2433                 $whitelisted = false;
2434                 if ( User::isEveryoneAllowed( 'read' ) ) {
2435                         # Shortcut for public wikis, allows skipping quite a bit of code
2436                         $whitelisted = true;
2437                 } elseif ( $user->isAllowed( 'read' ) ) {
2438                         # If the user is allowed to read pages, he is allowed to read all pages
2439                         $whitelisted = true;
2440                 } elseif ( $this->isSpecial( 'Userlogin' )
2441                         || $this->isSpecial( 'PasswordReset' )
2442                         || $this->isSpecial( 'Userlogout' )
2443                 ) {
2444                         # Always grant access to the login page.
2445                         # Even anons need to be able to log in.
2446                         $whitelisted = true;
2447                 } elseif ( is_array( $wgWhitelistRead ) && count( $wgWhitelistRead ) ) {
2448                         # Time to check the whitelist
2449                         # Only do these checks is there's something to check against
2450                         $name = $this->getPrefixedText();
2451                         $dbName = $this->getPrefixedDBkey();
2452
2453                         // Check for explicit whitelisting with and without underscores
2454                         if ( in_array( $name, $wgWhitelistRead, true ) || in_array( $dbName, $wgWhitelistRead, true ) ) {
2455                                 $whitelisted = true;
2456                         } elseif ( $this->getNamespace() == NS_MAIN ) {
2457                                 # Old settings might have the title prefixed with
2458                                 # a colon for main-namespace pages
2459                                 if ( in_array( ':' . $name, $wgWhitelistRead ) ) {
2460                                         $whitelisted = true;
2461                                 }
2462                         } elseif ( $this->isSpecialPage() ) {
2463                                 # If it's a special page, ditch the subpage bit and check again
2464                                 $name = $this->getDBkey();
2465                                 list( $name, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $name );
2466                                 if ( $name ) {
2467                                         $pure = SpecialPage::getTitleFor( $name )->getPrefixedText();
2468                                         if ( in_array( $pure, $wgWhitelistRead, true ) ) {
2469                                                 $whitelisted = true;
2470                                         }
2471                                 }
2472                         }
2473                 }
2474
2475                 if ( !$whitelisted && is_array( $wgWhitelistReadRegexp ) && !empty( $wgWhitelistReadRegexp ) ) {
2476                         $name = $this->getPrefixedText();
2477                         // Check for regex whitelisting
2478                         foreach ( $wgWhitelistReadRegexp as $listItem ) {
2479                                 if ( preg_match( $listItem, $name ) ) {
2480                                         $whitelisted = true;
2481                                         break;
2482                                 }
2483                         }
2484                 }
2485
2486                 if ( !$whitelisted ) {
2487                         # If the title is not whitelisted, give extensions a chance to do so...
2488                         Hooks::run( 'TitleReadWhitelist', [ $this, $user, &$whitelisted ] );
2489                         if ( !$whitelisted ) {
2490                                 $errors[] = $this->missingPermissionError( $action, $short );
2491                         }
2492                 }
2493
2494                 return $errors;
2495         }
2496
2497         /**
2498          * Get a description array when the user doesn't have the right to perform
2499          * $action (i.e. when User::isAllowed() returns false)
2500          *
2501          * @param string $action The action to check
2502          * @param bool $short Short circuit on first error
2503          * @return array Array containing an error message key and any parameters
2504          */
2505         private function missingPermissionError( $action, $short ) {
2506                 // We avoid expensive display logic for quickUserCan's and such
2507                 if ( $short ) {
2508                         return [ 'badaccess-group0' ];
2509                 }
2510
2511                 return User::newFatalPermissionDeniedStatus( $action )->getErrorsArray()[0];
2512         }
2513
2514         /**
2515          * Can $user perform $action on this page? This is an internal function,
2516          * with multiple levels of checks depending on performance needs; see $rigor below.
2517          * It does not check wfReadOnly().
2518          *
2519          * @param string $action Action that permission needs to be checked for
2520          * @param User $user User to check
2521          * @param string $rigor One of (quick,full,secure)
2522          *   - quick  : does cheap permission checks from replica DBs (usable for GUI creation)
2523          *   - full   : does cheap and expensive checks possibly from a replica DB
2524          *   - secure : does cheap and expensive checks, using the master as needed
2525          * @param bool $short Set this to true to stop after the first permission error.
2526          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
2527          */
2528         protected function getUserPermissionsErrorsInternal(
2529                 $action, $user, $rigor = 'secure', $short = false
2530         ) {
2531                 if ( $rigor === true ) {
2532                         $rigor = 'secure'; // b/c
2533                 } elseif ( $rigor === false ) {
2534                         $rigor = 'quick'; // b/c
2535                 } elseif ( !in_array( $rigor, [ 'quick', 'full', 'secure' ] ) ) {
2536                         throw new Exception( "Invalid rigor parameter '$rigor'." );
2537                 }
2538
2539                 # Read has special handling
2540                 if ( $action == 'read' ) {
2541                         $checks = [
2542                                 'checkPermissionHooks',
2543                                 'checkReadPermissions',
2544                                 'checkUserBlock', // for wgBlockDisablesLogin
2545                         ];
2546                 # Don't call checkSpecialsAndNSPermissions or checkCSSandJSPermissions
2547                 # here as it will lead to duplicate error messages. This is okay to do
2548                 # since anywhere that checks for create will also check for edit, and
2549                 # those checks are called for edit.
2550                 } elseif ( $action == 'create' ) {
2551                         $checks = [
2552                                 'checkQuickPermissions',
2553                                 'checkPermissionHooks',
2554                                 'checkPageRestrictions',
2555                                 'checkCascadingSourcesRestrictions',
2556                                 'checkActionPermissions',
2557                                 'checkUserBlock'
2558                         ];
2559                 } else {
2560                         $checks = [
2561                                 'checkQuickPermissions',
2562                                 'checkPermissionHooks',
2563                                 'checkSpecialsAndNSPermissions',
2564                                 'checkCSSandJSPermissions',
2565                                 'checkPageRestrictions',
2566                                 'checkCascadingSourcesRestrictions',
2567                                 'checkActionPermissions',
2568                                 'checkUserBlock'
2569                         ];
2570                 }
2571
2572                 $errors = [];
2573                 while ( count( $checks ) > 0 &&
2574                                 !( $short && count( $errors ) > 0 ) ) {
2575                         $method = array_shift( $checks );
2576                         $errors = $this->$method( $action, $user, $errors, $rigor, $short );
2577                 }
2578
2579                 return $errors;
2580         }
2581
2582         /**
2583          * Get a filtered list of all restriction types supported by this wiki.
2584          * @param bool $exists True to get all restriction types that apply to
2585          * titles that do exist, False for all restriction types that apply to
2586          * titles that do not exist
2587          * @return array
2588          */
2589         public static function getFilteredRestrictionTypes( $exists = true ) {
2590                 global $wgRestrictionTypes;
2591                 $types = $wgRestrictionTypes;
2592                 if ( $exists ) {
2593                         # Remove the create restriction for existing titles
2594                         $types = array_diff( $types, [ 'create' ] );
2595                 } else {
2596                         # Only the create and upload restrictions apply to non-existing titles
2597                         $types = array_intersect( $types, [ 'create', 'upload' ] );
2598                 }
2599                 return $types;
2600         }
2601
2602         /**
2603          * Returns restriction types for the current Title
2604          *
2605          * @return array Applicable restriction types
2606          */
2607         public function getRestrictionTypes() {
2608                 if ( $this->isSpecialPage() ) {
2609                         return [];
2610                 }
2611
2612                 $types = self::getFilteredRestrictionTypes( $this->exists() );
2613
2614                 if ( $this->getNamespace() != NS_FILE ) {
2615                         # Remove the upload restriction for non-file titles
2616                         $types = array_diff( $types, [ 'upload' ] );
2617                 }
2618
2619                 Hooks::run( 'TitleGetRestrictionTypes', [ $this, &$types ] );
2620
2621                 wfDebug( __METHOD__ . ': applicable restrictions to [[' .
2622                         $this->getPrefixedText() . ']] are {' . implode( ',', $types ) . "}\n" );
2623
2624                 return $types;
2625         }
2626
2627         /**
2628          * Is this title subject to title protection?
2629          * Title protection is the one applied against creation of such title.
2630          *
2631          * @return array|bool An associative array representing any existent title
2632          *   protection, or false if there's none.
2633          */
2634         public function getTitleProtection() {
2635                 $protection = $this->getTitleProtectionInternal();
2636                 if ( $protection ) {
2637                         if ( $protection['permission'] == 'sysop' ) {
2638                                 $protection['permission'] = 'editprotected'; // B/C
2639                         }
2640                         if ( $protection['permission'] == 'autoconfirmed' ) {
2641                                 $protection['permission'] = 'editsemiprotected'; // B/C
2642                         }
2643                 }
2644                 return $protection;
2645         }
2646
2647         /**
2648          * Fetch title protection settings
2649          *
2650          * To work correctly, $this->loadRestrictions() needs to have access to the
2651          * actual protections in the database without munging 'sysop' =>
2652          * 'editprotected' and 'autoconfirmed' => 'editsemiprotected'. Other
2653          * callers probably want $this->getTitleProtection() instead.
2654          *
2655          * @return array|bool
2656          */
2657         protected function getTitleProtectionInternal() {
2658                 // Can't protect pages in special namespaces
2659                 if ( $this->getNamespace() < 0 ) {
2660                         return false;
2661                 }
2662
2663                 // Can't protect pages that exist.
2664                 if ( $this->exists() ) {
2665                         return false;
2666                 }
2667
2668                 if ( $this->mTitleProtection === null ) {
2669                         $dbr = wfGetDB( DB_REPLICA );
2670                         $res = $dbr->select(
2671                                 'protected_titles',
2672                                 [
2673                                         'user' => 'pt_user',
2674                                         'reason' => 'pt_reason',
2675                                         'expiry' => 'pt_expiry',
2676                                         'permission' => 'pt_create_perm'
2677                                 ],
2678                                 [ 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ],
2679                                 __METHOD__
2680                         );
2681
2682                         // fetchRow returns false if there are no rows.
2683                         $row = $dbr->fetchRow( $res );
2684                         if ( $row ) {
2685                                 $row['expiry'] = $dbr->decodeExpiry( $row['expiry'] );
2686                         }
2687                         $this->mTitleProtection = $row;
2688                 }
2689                 return $this->mTitleProtection;
2690         }
2691
2692         /**
2693          * Remove any title protection due to page existing
2694          */
2695         public function deleteTitleProtection() {
2696                 $dbw = wfGetDB( DB_MASTER );
2697
2698                 $dbw->delete(
2699                         'protected_titles',
2700                         [ 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ],
2701                         __METHOD__
2702                 );
2703                 $this->mTitleProtection = false;
2704         }
2705
2706         /**
2707          * Is this page "semi-protected" - the *only* protection levels are listed
2708          * in $wgSemiprotectedRestrictionLevels?
2709          *
2710          * @param string $action Action to check (default: edit)
2711          * @return bool
2712          */
2713         public function isSemiProtected( $action = 'edit' ) {
2714                 global $wgSemiprotectedRestrictionLevels;
2715
2716                 $restrictions = $this->getRestrictions( $action );
2717                 $semi = $wgSemiprotectedRestrictionLevels;
2718                 if ( !$restrictions || !$semi ) {
2719                         // Not protected, or all protection is full protection
2720                         return false;
2721                 }
2722
2723                 // Remap autoconfirmed to editsemiprotected for BC
2724                 foreach ( array_keys( $semi, 'autoconfirmed' ) as $key ) {
2725                         $semi[$key] = 'editsemiprotected';
2726                 }
2727                 foreach ( array_keys( $restrictions, 'autoconfirmed' ) as $key ) {
2728                         $restrictions[$key] = 'editsemiprotected';
2729                 }
2730
2731                 return !array_diff( $restrictions, $semi );
2732         }
2733
2734         /**
2735          * Does the title correspond to a protected article?
2736          *
2737          * @param string $action The action the page is protected from,
2738          * by default checks all actions.
2739          * @return bool
2740          */
2741         public function isProtected( $action = '' ) {
2742                 global $wgRestrictionLevels;
2743
2744                 $restrictionTypes = $this->getRestrictionTypes();
2745
2746                 # Special pages have inherent protection
2747                 if ( $this->isSpecialPage() ) {
2748                         return true;
2749                 }
2750
2751                 # Check regular protection levels
2752                 foreach ( $restrictionTypes as $type ) {
2753                         if ( $action == $type || $action == '' ) {
2754                                 $r = $this->getRestrictions( $type );
2755                                 foreach ( $wgRestrictionLevels as $level ) {
2756                                         if ( in_array( $level, $r ) && $level != '' ) {
2757                                                 return true;
2758                                         }
2759                                 }
2760                         }
2761                 }
2762
2763                 return false;
2764         }
2765
2766         /**
2767          * Determines if $user is unable to edit this page because it has been protected
2768          * by $wgNamespaceProtection.
2769          *
2770          * @param User $user User object to check permissions
2771          * @return bool
2772          */
2773         public function isNamespaceProtected( User $user ) {
2774                 global $wgNamespaceProtection;
2775
2776                 if ( isset( $wgNamespaceProtection[$this->mNamespace] ) ) {
2777                         foreach ( (array)$wgNamespaceProtection[$this->mNamespace] as $right ) {
2778                                 if ( $right != '' && !$user->isAllowed( $right ) ) {
2779                                         return true;
2780                                 }
2781                         }
2782                 }
2783                 return false;
2784         }
2785
2786         /**
2787          * Cascading protection: Return true if cascading restrictions apply to this page, false if not.
2788          *
2789          * @return bool If the page is subject to cascading restrictions.
2790          */
2791         public function isCascadeProtected() {
2792                 list( $sources, /* $restrictions */ ) = $this->getCascadeProtectionSources( false );
2793                 return ( $sources > 0 );
2794         }
2795
2796         /**
2797          * Determines whether cascading protection sources have already been loaded from
2798          * the database.
2799          *
2800          * @param bool $getPages True to check if the pages are loaded, or false to check
2801          * if the status is loaded.
2802          * @return bool Whether or not the specified information has been loaded
2803          * @since 1.23
2804          */
2805         public function areCascadeProtectionSourcesLoaded( $getPages = true ) {
2806                 return $getPages ? $this->mCascadeSources !== null : $this->mHasCascadingRestrictions !== null;
2807         }
2808
2809         /**
2810          * Cascading protection: Get the source of any cascading restrictions on this page.
2811          *
2812          * @param bool $getPages Whether or not to retrieve the actual pages
2813          *        that the restrictions have come from and the actual restrictions
2814          *        themselves.
2815          * @return array Two elements: First is an array of Title objects of the
2816          *        pages from which cascading restrictions have come, false for
2817          *        none, or true if such restrictions exist but $getPages was not
2818          *        set. Second is an array like that returned by
2819          *        Title::getAllRestrictions(), or an empty array if $getPages is
2820          *        false.
2821          */
2822         public function getCascadeProtectionSources( $getPages = true ) {
2823                 $pagerestrictions = [];
2824
2825                 if ( $this->mCascadeSources !== null && $getPages ) {
2826                         return [ $this->mCascadeSources, $this->mCascadingRestrictions ];
2827                 } elseif ( $this->mHasCascadingRestrictions !== null && !$getPages ) {
2828                         return [ $this->mHasCascadingRestrictions, $pagerestrictions ];
2829                 }
2830
2831                 $dbr = wfGetDB( DB_REPLICA );
2832
2833                 if ( $this->getNamespace() == NS_FILE ) {
2834                         $tables = [ 'imagelinks', 'page_restrictions' ];
2835                         $where_clauses = [
2836                                 'il_to' => $this->getDBkey(),
2837                                 'il_from=pr_page',
2838                                 'pr_cascade' => 1
2839                         ];
2840                 } else {
2841                         $tables = [ 'templatelinks', 'page_restrictions' ];
2842                         $where_clauses = [
2843                                 'tl_namespace' => $this->getNamespace(),
2844                                 'tl_title' => $this->getDBkey(),
2845                                 'tl_from=pr_page',
2846                                 'pr_cascade' => 1
2847                         ];
2848                 }
2849
2850                 if ( $getPages ) {
2851                         $cols = [ 'pr_page', 'page_namespace', 'page_title',
2852                                 'pr_expiry', 'pr_type', 'pr_level' ];
2853                         $where_clauses[] = 'page_id=pr_page';
2854                         $tables[] = 'page';
2855                 } else {
2856                         $cols = [ 'pr_expiry' ];
2857                 }
2858
2859                 $res = $dbr->select( $tables, $cols, $where_clauses, __METHOD__ );
2860
2861                 $sources = $getPages ? [] : false;
2862                 $now = wfTimestampNow();
2863
2864                 foreach ( $res as $row ) {
2865                         $expiry = $dbr->decodeExpiry( $row->pr_expiry );
2866                         if ( $expiry > $now ) {
2867                                 if ( $getPages ) {
2868                                         $page_id = $row->pr_page;
2869                                         $page_ns = $row->page_namespace;
2870                                         $page_title = $row->page_title;
2871                                         $sources[$page_id] = self::makeTitle( $page_ns, $page_title );
2872                                         # Add groups needed for each restriction type if its not already there
2873                                         # Make sure this restriction type still exists
2874
2875                                         if ( !isset( $pagerestrictions[$row->pr_type] ) ) {
2876                                                 $pagerestrictions[$row->pr_type] = [];
2877                                         }
2878
2879                                         if (
2880                                                 isset( $pagerestrictions[$row->pr_type] )
2881                                                 && !in_array( $row->pr_level, $pagerestrictions[$row->pr_type] )
2882                                         ) {
2883                                                 $pagerestrictions[$row->pr_type][] = $row->pr_level;
2884                                         }
2885                                 } else {
2886                                         $sources = true;
2887                                 }
2888                         }
2889                 }
2890
2891                 if ( $getPages ) {
2892                         $this->mCascadeSources = $sources;
2893                         $this->mCascadingRestrictions = $pagerestrictions;
2894                 } else {
2895                         $this->mHasCascadingRestrictions = $sources;
2896                 }
2897
2898                 return [ $sources, $pagerestrictions ];
2899         }
2900
2901         /**
2902          * Accessor for mRestrictionsLoaded
2903          *
2904          * @return bool Whether or not the page's restrictions have already been
2905          * loaded from the database
2906          * @since 1.23
2907          */
2908         public function areRestrictionsLoaded() {
2909                 return $this->mRestrictionsLoaded;
2910         }
2911
2912         /**
2913          * Accessor/initialisation for mRestrictions
2914          *
2915          * @param string $action Action that permission needs to be checked for
2916          * @return array Restriction levels needed to take the action. All levels are
2917          *     required. Note that restriction levels are normally user rights, but 'sysop'
2918          *     and 'autoconfirmed' are also allowed for backwards compatibility. These should
2919          *     be mapped to 'editprotected' and 'editsemiprotected' respectively.
2920          */
2921         public function getRestrictions( $action ) {
2922                 if ( !$this->mRestrictionsLoaded ) {
2923                         $this->loadRestrictions();
2924                 }
2925                 return isset( $this->mRestrictions[$action] )
2926                                 ? $this->mRestrictions[$action]
2927                                 : [];
2928         }
2929
2930         /**
2931          * Accessor/initialisation for mRestrictions
2932          *
2933          * @return array Keys are actions, values are arrays as returned by
2934          *     Title::getRestrictions()
2935          * @since 1.23
2936          */
2937         public function getAllRestrictions() {
2938                 if ( !$this->mRestrictionsLoaded ) {
2939                         $this->loadRestrictions();
2940                 }
2941                 return $this->mRestrictions;
2942         }
2943
2944         /**
2945          * Get the expiry time for the restriction against a given action
2946          *
2947          * @param string $action
2948          * @return string|bool 14-char timestamp, or 'infinity' if the page is protected forever
2949          *     or not protected at all, or false if the action is not recognised.
2950          */
2951         public function getRestrictionExpiry( $action ) {
2952                 if ( !$this->mRestrictionsLoaded ) {
2953                         $this->loadRestrictions();
2954                 }
2955                 return isset( $this->mRestrictionsExpiry[$action] ) ? $this->mRestrictionsExpiry[$action] : false;
2956         }
2957
2958         /**
2959          * Returns cascading restrictions for the current article
2960          *
2961          * @return bool
2962          */
2963         function areRestrictionsCascading() {
2964                 if ( !$this->mRestrictionsLoaded ) {
2965                         $this->loadRestrictions();
2966                 }
2967
2968                 return $this->mCascadeRestriction;
2969         }
2970
2971         /**
2972          * Compiles list of active page restrictions from both page table (pre 1.10)
2973          * and page_restrictions table for this existing page.
2974          * Public for usage by LiquidThreads.
2975          *
2976          * @param array $rows Array of db result objects
2977          * @param string $oldFashionedRestrictions Comma-separated list of page
2978          *   restrictions from page table (pre 1.10)
2979          */
2980         public function loadRestrictionsFromRows( $rows, $oldFashionedRestrictions = null ) {
2981                 $dbr = wfGetDB( DB_REPLICA );
2982
2983                 $restrictionTypes = $this->getRestrictionTypes();
2984
2985                 foreach ( $restrictionTypes as $type ) {
2986                         $this->mRestrictions[$type] = [];
2987                         $this->mRestrictionsExpiry[$type] = 'infinity';
2988                 }
2989
2990                 $this->mCascadeRestriction = false;
2991
2992                 # Backwards-compatibility: also load the restrictions from the page record (old format).
2993                 if ( $oldFashionedRestrictions !== null ) {
2994                         $this->mOldRestrictions = $oldFashionedRestrictions;
2995                 }
2996
2997                 if ( $this->mOldRestrictions === false ) {
2998                         $this->mOldRestrictions = $dbr->selectField( 'page', 'page_restrictions',
2999                                 [ 'page_id' => $this->getArticleID() ], __METHOD__ );
3000                 }
3001
3002                 if ( $this->mOldRestrictions != '' ) {
3003                         foreach ( explode( ':', trim( $this->mOldRestrictions ) ) as $restrict ) {
3004                                 $temp = explode( '=', trim( $restrict ) );
3005                                 if ( count( $temp ) == 1 ) {
3006                                         // old old format should be treated as edit/move restriction
3007                                         $this->mRestrictions['edit'] = explode( ',', trim( $temp[0] ) );
3008                                         $this->mRestrictions['move'] = explode( ',', trim( $temp[0] ) );
3009                                 } else {
3010                                         $restriction = trim( $temp[1] );
3011                                         if ( $restriction != '' ) { // some old entries are empty
3012                                                 $this->mRestrictions[$temp[0]] = explode( ',', $restriction );
3013                                         }
3014                                 }
3015                         }
3016                 }
3017
3018                 if ( count( $rows ) ) {
3019                         # Current system - load second to make them override.
3020                         $now = wfTimestampNow();
3021
3022                         # Cycle through all the restrictions.
3023                         foreach ( $rows as $row ) {
3024                                 // Don't take care of restrictions types that aren't allowed
3025                                 if ( !in_array( $row->pr_type, $restrictionTypes ) ) {
3026                                         continue;
3027                                 }
3028
3029                                 $expiry = $dbr->decodeExpiry( $row->pr_expiry );
3030
3031                                 // Only apply the restrictions if they haven't expired!
3032                                 if ( !$expiry || $expiry > $now ) {
3033                                         $this->mRestrictionsExpiry[$row->pr_type] = $expiry;
3034                                         $this->mRestrictions[$row->pr_type] = explode( ',', trim( $row->pr_level ) );
3035
3036                                         $this->mCascadeRestriction |= $row->pr_cascade;
3037                                 }
3038                         }
3039                 }
3040
3041                 $this->mRestrictionsLoaded = true;
3042         }
3043
3044         /**
3045          * Load restrictions from the page_restrictions table
3046          *
3047          * @param string $oldFashionedRestrictions Comma-separated list of page
3048          *   restrictions from page table (pre 1.10)
3049          */
3050         public function loadRestrictions( $oldFashionedRestrictions = null ) {
3051                 if ( $this->mRestrictionsLoaded ) {
3052                         return;
3053                 }
3054
3055                 $id = $this->getArticleID();
3056                 if ( $id ) {
3057                         $cache = ObjectCache::getMainWANInstance();
3058                         $rows = $cache->getWithSetCallback(
3059                                 // Page protections always leave a new null revision
3060                                 $cache->makeKey( 'page-restrictions', $id, $this->getLatestRevID() ),
3061                                 $cache::TTL_DAY,
3062                                 function ( $curValue, &$ttl, array &$setOpts ) {
3063                                         $dbr = wfGetDB( DB_REPLICA );
3064
3065                                         $setOpts += Database::getCacheSetOptions( $dbr );
3066
3067                                         return iterator_to_array(
3068                                                 $dbr->select(
3069                                                         'page_restrictions',
3070                                                         [ 'pr_type', 'pr_expiry', 'pr_level', 'pr_cascade' ],
3071                                                         [ 'pr_page' => $this->getArticleID() ],
3072                                                         __METHOD__
3073                                                 )
3074                                         );
3075                                 }
3076                         );
3077
3078                         $this->loadRestrictionsFromRows( $rows, $oldFashionedRestrictions );
3079                 } else {
3080                         $title_protection = $this->getTitleProtectionInternal();
3081
3082                         if ( $title_protection ) {
3083                                 $now = wfTimestampNow();
3084                                 $expiry = wfGetDB( DB_REPLICA )->decodeExpiry( $title_protection['expiry'] );
3085
3086                                 if ( !$expiry || $expiry > $now ) {
3087                                         // Apply the restrictions
3088                                         $this->mRestrictionsExpiry['create'] = $expiry;
3089                                         $this->mRestrictions['create'] =
3090                                                 explode( ',', trim( $title_protection['permission'] ) );
3091                                 } else { // Get rid of the old restrictions
3092                                         $this->mTitleProtection = false;
3093                                 }
3094                         } else {
3095                                 $this->mRestrictionsExpiry['create'] = 'infinity';
3096                         }
3097                         $this->mRestrictionsLoaded = true;
3098                 }
3099         }
3100
3101         /**
3102          * Flush the protection cache in this object and force reload from the database.
3103          * This is used when updating protection from WikiPage::doUpdateRestrictions().
3104          */
3105         public function flushRestrictions() {
3106                 $this->mRestrictionsLoaded = false;
3107                 $this->mTitleProtection = null;
3108         }
3109
3110         /**
3111          * Purge expired restrictions from the page_restrictions table
3112          *
3113          * This will purge no more than $wgUpdateRowsPerQuery page_restrictions rows
3114          */
3115         static function purgeExpiredRestrictions() {
3116                 if ( wfReadOnly() ) {
3117                         return;
3118                 }
3119
3120                 DeferredUpdates::addUpdate( new AtomicSectionUpdate(
3121                         wfGetDB( DB_MASTER ),
3122                         __METHOD__,
3123                         function ( IDatabase $dbw, $fname ) {
3124                                 $config = MediaWikiServices::getInstance()->getMainConfig();
3125                                 $ids = $dbw->selectFieldValues(
3126                                         'page_restrictions',
3127                                         'pr_id',
3128                                         [ 'pr_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ],
3129                                         $fname,
3130                                         [ 'LIMIT' => $config->get( 'UpdateRowsPerQuery' ) ] // T135470
3131                                 );
3132                                 if ( $ids ) {
3133                                         $dbw->delete( 'page_restrictions', [ 'pr_id' => $ids ], $fname );
3134                                 }
3135                         }
3136                 ) );
3137
3138                 DeferredUpdates::addUpdate( new AtomicSectionUpdate(
3139                         wfGetDB( DB_MASTER ),
3140                         __METHOD__,
3141                         function ( IDatabase $dbw, $fname ) {
3142                                 $dbw->delete(
3143                                         'protected_titles',
3144                                         [ 'pt_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ],
3145                                         $fname
3146                                 );
3147                         }
3148                 ) );
3149         }
3150
3151         /**
3152          * Does this have subpages?  (Warning, usually requires an extra DB query.)
3153          *
3154          * @return bool
3155          */
3156         public function hasSubpages() {
3157                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
3158                         # Duh
3159                         return false;
3160                 }
3161
3162                 # We dynamically add a member variable for the purpose of this method
3163                 # alone to cache the result.  There's no point in having it hanging
3164                 # around uninitialized in every Title object; therefore we only add it
3165                 # if needed and don't declare it statically.
3166                 if ( $this->mHasSubpages === null ) {
3167                         $this->mHasSubpages = false;
3168                         $subpages = $this->getSubpages( 1 );
3169                         if ( $subpages instanceof TitleArray ) {
3170                                 $this->mHasSubpages = (bool)$subpages->count();
3171                         }
3172                 }
3173
3174                 return $this->mHasSubpages;
3175         }
3176
3177         /**
3178          * Get all subpages of this page.
3179          *
3180          * @param int $limit Maximum number of subpages to fetch; -1 for no limit
3181          * @return TitleArray|array TitleArray, or empty array if this page's namespace
3182          *  doesn't allow subpages
3183          */
3184         public function getSubpages( $limit = -1 ) {
3185                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3186                         return [];
3187                 }
3188
3189                 $dbr = wfGetDB( DB_REPLICA );
3190                 $conds['page_namespace'] = $this->getNamespace();
3191                 $conds[] = 'page_title ' . $dbr->buildLike( $this->getDBkey() . '/', $dbr->anyString() );
3192                 $options = [];
3193                 if ( $limit > -1 ) {
3194                         $options['LIMIT'] = $limit;
3195                 }
3196                 return TitleArray::newFromResult(
3197                         $dbr->select( 'page',
3198                                 [ 'page_id', 'page_namespace', 'page_title', 'page_is_redirect' ],
3199                                 $conds,
3200                                 __METHOD__,
3201                                 $options
3202                         )
3203                 );
3204         }
3205
3206         /**
3207          * Is there a version of this page in the deletion archive?
3208          *
3209          * @return int The number of archived revisions
3210          */
3211         public function isDeleted() {
3212                 if ( $this->getNamespace() < 0 ) {
3213                         $n = 0;
3214                 } else {
3215                         $dbr = wfGetDB( DB_REPLICA );
3216
3217                         $n = $dbr->selectField( 'archive', 'COUNT(*)',
3218                                 [ 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ],
3219                                 __METHOD__
3220                         );
3221                         if ( $this->getNamespace() == NS_FILE ) {
3222                                 $n += $dbr->selectField( 'filearchive', 'COUNT(*)',
3223                                         [ 'fa_name' => $this->getDBkey() ],
3224                                         __METHOD__
3225                                 );
3226                         }
3227                 }
3228                 return (int)$n;
3229         }
3230
3231         /**
3232          * Is there a version of this page in the deletion archive?
3233          *
3234          * @return bool
3235          */
3236         public function isDeletedQuick() {
3237                 if ( $this->getNamespace() < 0 ) {
3238                         return false;
3239                 }
3240                 $dbr = wfGetDB( DB_REPLICA );
3241                 $deleted = (bool)$dbr->selectField( 'archive', '1',
3242                         [ 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ],
3243                         __METHOD__
3244                 );
3245                 if ( !$deleted && $this->getNamespace() == NS_FILE ) {
3246                         $deleted = (bool)$dbr->selectField( 'filearchive', '1',
3247                                 [ 'fa_name' => $this->getDBkey() ],
3248                                 __METHOD__
3249                         );
3250                 }
3251                 return $deleted;
3252         }
3253
3254         /**
3255          * Get the article ID for this Title from the link cache,
3256          * adding it if necessary
3257          *
3258          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select
3259          *  for update
3260          * @return int The ID
3261          */
3262         public function getArticleID( $flags = 0 ) {
3263                 if ( $this->getNamespace() < 0 ) {
3264                         $this->mArticleID = 0;
3265                         return $this->mArticleID;
3266                 }
3267                 $linkCache = LinkCache::singleton();
3268                 if ( $flags & self::GAID_FOR_UPDATE ) {
3269                         $oldUpdate = $linkCache->forUpdate( true );
3270                         $linkCache->clearLink( $this );
3271                         $this->mArticleID = $linkCache->addLinkObj( $this );
3272                         $linkCache->forUpdate( $oldUpdate );
3273                 } else {
3274                         if ( -1 == $this->mArticleID ) {
3275                                 $this->mArticleID = $linkCache->addLinkObj( $this );
3276                         }
3277                 }
3278                 return $this->mArticleID;
3279         }
3280
3281         /**
3282          * Is this an article that is a redirect page?
3283          * Uses link cache, adding it if necessary
3284          *
3285          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3286          * @return bool
3287          */
3288         public function isRedirect( $flags = 0 ) {
3289                 if ( !is_null( $this->mRedirect ) ) {
3290                         return $this->mRedirect;
3291                 }
3292                 if ( !$this->getArticleID( $flags ) ) {
3293                         $this->mRedirect = false;
3294                         return $this->mRedirect;
3295                 }
3296
3297                 $linkCache = LinkCache::singleton();
3298                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3299                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'redirect' );
3300                 if ( $cached === null ) {
3301                         # Trust LinkCache's state over our own
3302                         # LinkCache is telling us that the page doesn't exist, despite there being cached
3303                         # data relating to an existing page in $this->mArticleID. Updaters should clear
3304                         # LinkCache as appropriate, or use $flags = Title::GAID_FOR_UPDATE. If that flag is
3305                         # set, then LinkCache will definitely be up to date here, since getArticleID() forces
3306                         # LinkCache to refresh its data from the master.
3307                         $this->mRedirect = false;
3308                         return $this->mRedirect;
3309                 }
3310
3311                 $this->mRedirect = (bool)$cached;
3312
3313                 return $this->mRedirect;
3314         }
3315
3316         /**
3317          * What is the length of this page?
3318          * Uses link cache, adding it if necessary
3319          *
3320          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3321          * @return int
3322          */
3323         public function getLength( $flags = 0 ) {
3324                 if ( $this->mLength != -1 ) {
3325                         return $this->mLength;
3326                 }
3327                 if ( !$this->getArticleID( $flags ) ) {
3328                         $this->mLength = 0;
3329                         return $this->mLength;
3330                 }
3331                 $linkCache = LinkCache::singleton();
3332                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3333                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'length' );
3334                 if ( $cached === null ) {
3335                         # Trust LinkCache's state over our own, as for isRedirect()
3336                         $this->mLength = 0;
3337                         return $this->mLength;
3338                 }
3339
3340                 $this->mLength = intval( $cached );
3341
3342                 return $this->mLength;
3343         }
3344
3345         /**
3346          * What is the page_latest field for this page?
3347          *
3348          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3349          * @return int Int or 0 if the page doesn't exist
3350          */
3351         public function getLatestRevID( $flags = 0 ) {
3352                 if ( !( $flags & self::GAID_FOR_UPDATE ) && $this->mLatestID !== false ) {
3353                         return intval( $this->mLatestID );
3354                 }
3355                 if ( !$this->getArticleID( $flags ) ) {
3356                         $this->mLatestID = 0;
3357                         return $this->mLatestID;
3358                 }
3359                 $linkCache = LinkCache::singleton();
3360                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3361                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'revision' );
3362                 if ( $cached === null ) {
3363                         # Trust LinkCache's state over our own, as for isRedirect()
3364                         $this->mLatestID = 0;
3365                         return $this->mLatestID;
3366                 }
3367
3368                 $this->mLatestID = intval( $cached );
3369
3370                 return $this->mLatestID;
3371         }
3372
3373         /**
3374          * This clears some fields in this object, and clears any associated
3375          * keys in the "bad links" section of the link cache.
3376          *
3377          * - This is called from WikiPage::doEditContent() and WikiPage::insertOn() to allow
3378          * loading of the new page_id. It's also called from
3379          * WikiPage::doDeleteArticleReal()
3380          *
3381          * @param int $newid The new Article ID
3382          */
3383         public function resetArticleID( $newid ) {
3384                 $linkCache = LinkCache::singleton();
3385                 $linkCache->clearLink( $this );
3386
3387                 if ( $newid === false ) {
3388                         $this->mArticleID = -1;
3389                 } else {
3390                         $this->mArticleID = intval( $newid );
3391                 }
3392                 $this->mRestrictionsLoaded = false;
3393                 $this->mRestrictions = [];
3394                 $this->mOldRestrictions = false;
3395                 $this->mRedirect = null;
3396                 $this->mLength = -1;
3397                 $this->mLatestID = false;
3398                 $this->mContentModel = false;
3399                 $this->mEstimateRevisions = null;
3400                 $this->mPageLanguage = false;
3401                 $this->mDbPageLanguage = false;
3402                 $this->mIsBigDeletion = null;
3403         }
3404
3405         public static function clearCaches() {
3406                 $linkCache = LinkCache::singleton();
3407                 $linkCache->clear();
3408
3409                 $titleCache = self::getTitleCache();
3410                 $titleCache->clear();
3411         }
3412
3413         /**
3414          * Capitalize a text string for a title if it belongs to a namespace that capitalizes
3415          *
3416          * @param string $text Containing title to capitalize
3417          * @param int $ns Namespace index, defaults to NS_MAIN
3418          * @return string Containing capitalized title
3419          */
3420         public static function capitalize( $text, $ns = NS_MAIN ) {
3421                 global $wgContLang;
3422
3423                 if ( MWNamespace::isCapitalized( $ns ) ) {
3424                         return $wgContLang->ucfirst( $text );
3425                 } else {
3426                         return $text;
3427                 }
3428         }
3429
3430         /**
3431          * Secure and split - main initialisation function for this object
3432          *
3433          * Assumes that mDbkeyform has been set, and is urldecoded
3434          * and uses underscores, but not otherwise munged.  This function
3435          * removes illegal characters, splits off the interwiki and
3436          * namespace prefixes, sets the other forms, and canonicalizes
3437          * everything.
3438          *
3439          * @throws MalformedTitleException On invalid titles
3440          * @return bool True on success
3441          */
3442         private function secureAndSplit() {
3443                 # Initialisation
3444                 $this->mInterwiki = '';
3445                 $this->mFragment = '';
3446                 $this->mNamespace = $this->mDefaultNamespace; # Usually NS_MAIN
3447
3448                 $dbkey = $this->mDbkeyform;
3449
3450                 // @note: splitTitleString() is a temporary hack to allow MediaWikiTitleCodec to share
3451                 //        the parsing code with Title, while avoiding massive refactoring.
3452                 // @todo: get rid of secureAndSplit, refactor parsing code.
3453                 // @note: getTitleParser() returns a TitleParser implementation which does not have a
3454                 //        splitTitleString method, but the only implementation (MediaWikiTitleCodec) does
3455                 $titleCodec = MediaWikiServices::getInstance()->getTitleParser();
3456                 // MalformedTitleException can be thrown here
3457                 $parts = $titleCodec->splitTitleString( $dbkey, $this->getDefaultNamespace() );
3458
3459                 # Fill fields
3460                 $this->setFragment( '#' . $parts['fragment'] );
3461                 $this->mInterwiki = $parts['interwiki'];
3462                 $this->mLocalInterwiki = $parts['local_interwiki'];
3463                 $this->mNamespace = $parts['namespace'];
3464                 $this->mUserCaseDBKey = $parts['user_case_dbkey'];
3465
3466                 $this->mDbkeyform = $parts['dbkey'];
3467                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
3468                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
3469
3470                 # We already know that some pages won't be in the database!
3471                 if ( $this->isExternal() || $this->isSpecialPage() ) {
3472                         $this->mArticleID = 0;
3473                 }
3474
3475                 return true;
3476         }
3477
3478         /**
3479          * Get an array of Title objects linking to this Title
3480          * Also stores the IDs in the link cache.
3481          *
3482          * WARNING: do not use this function on arbitrary user-supplied titles!
3483          * On heavily-used templates it will max out the memory.
3484          *
3485          * @param array $options May be FOR UPDATE
3486          * @param string $table Table name
3487          * @param string $prefix Fields prefix
3488          * @return Title[] Array of Title objects linking here
3489          */
3490         public function getLinksTo( $options = [], $table = 'pagelinks', $prefix = 'pl' ) {
3491                 if ( count( $options ) > 0 ) {
3492                         $db = wfGetDB( DB_MASTER );
3493                 } else {
3494                         $db = wfGetDB( DB_REPLICA );
3495                 }
3496
3497                 $res = $db->select(
3498                         [ 'page', $table ],
3499                         self::getSelectFields(),
3500                         [
3501                                 "{$prefix}_from=page_id",
3502                                 "{$prefix}_namespace" => $this->getNamespace(),
3503                                 "{$prefix}_title" => $this->getDBkey() ],
3504                         __METHOD__,
3505                         $options
3506                 );
3507
3508                 $retVal = [];
3509                 if ( $res->numRows() ) {
3510                         $linkCache = LinkCache::singleton();
3511                         foreach ( $res as $row ) {
3512                                 $titleObj = self::makeTitle( $row->page_namespace, $row->page_title );
3513                                 if ( $titleObj ) {
3514                                         $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3515                                         $retVal[] = $titleObj;
3516                                 }
3517                         }
3518                 }
3519                 return $retVal;
3520         }
3521
3522         /**
3523          * Get an array of Title objects using this Title as a template
3524          * Also stores the IDs in the link cache.
3525          *
3526          * WARNING: do not use this function on arbitrary user-supplied titles!
3527          * On heavily-used templates it will max out the memory.
3528          *
3529          * @param array $options Query option to Database::select()
3530          * @return Title[] Array of Title the Title objects linking here
3531          */
3532         public function getTemplateLinksTo( $options = [] ) {
3533                 return $this->getLinksTo( $options, 'templatelinks', 'tl' );
3534         }
3535
3536         /**
3537          * Get an array of Title objects linked from this Title
3538          * Also stores the IDs in the link cache.
3539          *
3540          * WARNING: do not use this function on arbitrary user-supplied titles!
3541          * On heavily-used templates it will max out the memory.
3542          *
3543          * @param array $options Query option to Database::select()
3544          * @param string $table Table name
3545          * @param string $prefix Fields prefix
3546          * @return array Array of Title objects linking here
3547          */
3548         public function getLinksFrom( $options = [], $table = 'pagelinks', $prefix = 'pl' ) {
3549                 $id = $this->getArticleID();
3550
3551                 # If the page doesn't exist; there can't be any link from this page
3552                 if ( !$id ) {
3553                         return [];
3554                 }
3555
3556                 $db = wfGetDB( DB_REPLICA );
3557
3558                 $blNamespace = "{$prefix}_namespace";
3559                 $blTitle = "{$prefix}_title";
3560
3561                 $res = $db->select(
3562                         [ $table, 'page' ],
3563                         array_merge(
3564                                 [ $blNamespace, $blTitle ],
3565                                 WikiPage::selectFields()
3566                         ),
3567                         [ "{$prefix}_from" => $id ],
3568                         __METHOD__,
3569                         $options,
3570                         [ 'page' => [
3571                                 'LEFT JOIN',
3572                                 [ "page_namespace=$blNamespace", "page_title=$blTitle" ]
3573                         ] ]
3574                 );
3575
3576                 $retVal = [];
3577                 $linkCache = LinkCache::singleton();
3578                 foreach ( $res as $row ) {
3579                         if ( $row->page_id ) {
3580                                 $titleObj = self::newFromRow( $row );
3581                         } else {
3582                                 $titleObj = self::makeTitle( $row->$blNamespace, $row->$blTitle );
3583                                 $linkCache->addBadLinkObj( $titleObj );
3584                         }
3585                         $retVal[] = $titleObj;
3586                 }
3587
3588                 return $retVal;
3589         }
3590
3591         /**
3592          * Get an array of Title objects used on this Title as a template
3593          * Also stores the IDs in the link cache.
3594          *
3595          * WARNING: do not use this function on arbitrary user-supplied titles!
3596          * On heavily-used templates it will max out the memory.
3597          *
3598          * @param array $options May be FOR UPDATE
3599          * @return Title[] Array of Title the Title objects used here
3600          */
3601         public function getTemplateLinksFrom( $options = [] ) {
3602                 return $this->getLinksFrom( $options, 'templatelinks', 'tl' );
3603         }
3604
3605         /**
3606          * Get an array of Title objects referring to non-existent articles linked
3607          * from this page.
3608          *
3609          * @todo check if needed (used only in SpecialBrokenRedirects.php, and
3610          *   should use redirect table in this case).
3611          * @return Title[] Array of Title the Title objects
3612          */
3613         public function getBrokenLinksFrom() {
3614                 if ( $this->getArticleID() == 0 ) {
3615                         # All links from article ID 0 are false positives
3616                         return [];
3617                 }
3618
3619                 $dbr = wfGetDB( DB_REPLICA );
3620                 $res = $dbr->select(
3621                         [ 'page', 'pagelinks' ],
3622                         [ 'pl_namespace', 'pl_title' ],
3623                         [
3624                                 'pl_from' => $this->getArticleID(),
3625                                 'page_namespace IS NULL'
3626                         ],
3627                         __METHOD__, [],
3628                         [
3629                                 'page' => [
3630                                         'LEFT JOIN',
3631                                         [ 'pl_namespace=page_namespace', 'pl_title=page_title' ]
3632                                 ]
3633                         ]
3634                 );
3635
3636                 $retVal = [];
3637                 foreach ( $res as $row ) {
3638                         $retVal[] = self::makeTitle( $row->pl_namespace, $row->pl_title );
3639                 }
3640                 return $retVal;
3641         }
3642
3643         /**
3644          * Get a list of URLs to purge from the CDN cache when this
3645          * page changes
3646          *
3647          * @return string[] Array of String the URLs
3648          */
3649         public function getCdnUrls() {
3650                 $urls = [
3651                         $this->getInternalURL(),
3652                         $this->getInternalURL( 'action=history' )
3653                 ];
3654
3655                 $pageLang = $this->getPageLanguage();
3656                 if ( $pageLang->hasVariants() ) {
3657                         $variants = $pageLang->getVariants();
3658                         foreach ( $variants as $vCode ) {
3659                                 $urls[] = $this->getInternalURL( $vCode );
3660                         }
3661                 }
3662
3663                 // If we are looking at a css/js user subpage, purge the action=raw.
3664                 if ( $this->isJsSubpage() ) {
3665                         $urls[] = $this->getInternalURL( 'action=raw&ctype=text/javascript' );
3666                 } elseif ( $this->isCssSubpage() ) {
3667                         $urls[] = $this->getInternalURL( 'action=raw&ctype=text/css' );
3668                 }
3669
3670                 Hooks::run( 'TitleSquidURLs', [ $this, &$urls ] );
3671                 return $urls;
3672         }
3673
3674         /**
3675          * @deprecated since 1.27 use getCdnUrls()
3676          */
3677         public function getSquidURLs() {
3678                 return $this->getCdnUrls();
3679         }
3680
3681         /**
3682          * Purge all applicable CDN URLs
3683          */
3684         public function purgeSquid() {
3685                 DeferredUpdates::addUpdate(
3686                         new CdnCacheUpdate( $this->getCdnUrls() ),
3687                         DeferredUpdates::PRESEND
3688                 );
3689         }
3690
3691         /**
3692          * Check whether a given move operation would be valid.
3693          * Returns true if ok, or a getUserPermissionsErrors()-like array otherwise
3694          *
3695          * @deprecated since 1.25, use MovePage's methods instead
3696          * @param Title $nt The new title
3697          * @param bool $auth Whether to check user permissions (uses $wgUser)
3698          * @param string $reason Is the log summary of the move, used for spam checking
3699          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3700          */
3701         public function isValidMoveOperation( &$nt, $auth = true, $reason = '' ) {
3702                 global $wgUser;
3703
3704                 if ( !( $nt instanceof Title ) ) {
3705                         // Normally we'd add this to $errors, but we'll get
3706                         // lots of syntax errors if $nt is not an object
3707                         return [ [ 'badtitletext' ] ];
3708                 }
3709
3710                 $mp = new MovePage( $this, $nt );
3711                 $errors = $mp->isValidMove()->getErrorsArray();
3712                 if ( $auth ) {
3713                         $errors = wfMergeErrorArrays(
3714                                 $errors,
3715                                 $mp->checkPermissions( $wgUser, $reason )->getErrorsArray()
3716                         );
3717                 }
3718
3719                 return $errors ?: true;
3720         }
3721
3722         /**
3723          * Check if the requested move target is a valid file move target
3724          * @todo move this to MovePage
3725          * @param Title $nt Target title
3726          * @return array List of errors
3727          */
3728         protected function validateFileMoveOperation( $nt ) {
3729                 global $wgUser;
3730
3731                 $errors = [];
3732
3733                 $destFile = wfLocalFile( $nt );
3734                 $destFile->load( File::READ_LATEST );
3735                 if ( !$wgUser->isAllowed( 'reupload-shared' )
3736                         && !$destFile->exists() && wfFindFile( $nt )
3737                 ) {
3738                         $errors[] = [ 'file-exists-sharedrepo' ];
3739                 }
3740
3741                 return $errors;
3742         }
3743
3744         /**
3745          * Move a title to a new location
3746          *
3747          * @deprecated since 1.25, use the MovePage class instead
3748          * @param Title $nt The new title
3749          * @param bool $auth Indicates whether $wgUser's permissions
3750          *  should be checked
3751          * @param string $reason The reason for the move
3752          * @param bool $createRedirect Whether to create a redirect from the old title to the new title.
3753          *  Ignored if the user doesn't have the suppressredirect right.
3754          * @param array $changeTags Applied to the entry in the move log and redirect page revision
3755          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3756          */
3757         public function moveTo( &$nt, $auth = true, $reason = '', $createRedirect = true,
3758                 array $changeTags = []
3759         ) {
3760                 global $wgUser;
3761                 $err = $this->isValidMoveOperation( $nt, $auth, $reason );
3762                 if ( is_array( $err ) ) {
3763                         // Auto-block user's IP if the account was "hard" blocked
3764                         $wgUser->spreadAnyEditBlock();
3765                         return $err;
3766                 }
3767                 // Check suppressredirect permission
3768                 if ( $auth && !$wgUser->isAllowed( 'suppressredirect' ) ) {
3769                         $createRedirect = true;
3770                 }
3771
3772                 $mp = new MovePage( $this, $nt );
3773                 $status = $mp->move( $wgUser, $reason, $createRedirect, $changeTags );
3774                 if ( $status->isOK() ) {
3775                         return true;
3776                 } else {
3777                         return $status->getErrorsArray();
3778                 }
3779         }
3780
3781         /**
3782          * Move this page's subpages to be subpages of $nt
3783          *
3784          * @param Title $nt Move target
3785          * @param bool $auth Whether $wgUser's permissions should be checked
3786          * @param string $reason The reason for the move
3787          * @param bool $createRedirect Whether to create redirects from the old subpages to
3788          *     the new ones Ignored if the user doesn't have the 'suppressredirect' right
3789          * @param array $changeTags Applied to the entry in the move log and redirect page revision
3790          * @return array Array with old page titles as keys, and strings (new page titles) or
3791          *     getUserPermissionsErrors()-like arrays (errors) as values, or a
3792          *     getUserPermissionsErrors()-like error array with numeric indices if
3793          *     no pages were moved
3794          */
3795         public function moveSubpages( $nt, $auth = true, $reason = '', $createRedirect = true,
3796                 array $changeTags = []
3797         ) {
3798                 global $wgMaximumMovedPages;
3799                 // Check permissions
3800                 if ( !$this->userCan( 'move-subpages' ) ) {
3801                         return [
3802                                 [ 'cant-move-subpages' ],
3803                         ];
3804                 }
3805                 // Do the source and target namespaces support subpages?
3806                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3807                         return [
3808                                 [ 'namespace-nosubpages', MWNamespace::getCanonicalName( $this->getNamespace() ) ],
3809                         ];
3810                 }
3811                 if ( !MWNamespace::hasSubpages( $nt->getNamespace() ) ) {
3812                         return [
3813                                 [ 'namespace-nosubpages', MWNamespace::getCanonicalName( $nt->getNamespace() ) ],
3814                         ];
3815                 }
3816
3817                 $subpages = $this->getSubpages( $wgMaximumMovedPages + 1 );
3818                 $retval = [];
3819                 $count = 0;
3820                 foreach ( $subpages as $oldSubpage ) {
3821                         $count++;
3822                         if ( $count > $wgMaximumMovedPages ) {
3823                                 $retval[$oldSubpage->getPrefixedText()] = [
3824                                         [ 'movepage-max-pages', $wgMaximumMovedPages ],
3825                                 ];
3826                                 break;
3827                         }
3828
3829                         // We don't know whether this function was called before
3830                         // or after moving the root page, so check both
3831                         // $this and $nt
3832                         if ( $oldSubpage->getArticleID() == $this->getArticleID()
3833                                 || $oldSubpage->getArticleID() == $nt->getArticleID()
3834                         ) {
3835                                 // When moving a page to a subpage of itself,
3836                                 // don't move it twice
3837                                 continue;
3838                         }
3839                         $newPageName = preg_replace(
3840                                         '#^' . preg_quote( $this->getDBkey(), '#' ) . '#',
3841                                         StringUtils::escapeRegexReplacement( $nt->getDBkey() ), # T23234
3842                                         $oldSubpage->getDBkey() );
3843                         if ( $oldSubpage->isTalkPage() ) {
3844                                 $newNs = $nt->getTalkPage()->getNamespace();
3845                         } else {
3846                                 $newNs = $nt->getSubjectPage()->getNamespace();
3847                         }
3848                         # T16385: we need makeTitleSafe because the new page names may
3849                         # be longer than 255 characters.
3850                         $newSubpage = self::makeTitleSafe( $newNs, $newPageName );
3851
3852                         $success = $oldSubpage->moveTo( $newSubpage, $auth, $reason, $createRedirect, $changeTags );
3853                         if ( $success === true ) {
3854                                 $retval[$oldSubpage->getPrefixedText()] = $newSubpage->getPrefixedText();
3855                         } else {
3856                                 $retval[$oldSubpage->getPrefixedText()] = $success;
3857                         }
3858                 }
3859                 return $retval;
3860         }
3861
3862         /**
3863          * Checks if this page is just a one-rev redirect.
3864          * Adds lock, so don't use just for light purposes.
3865          *
3866          * @return bool
3867          */
3868         public function isSingleRevRedirect() {
3869                 global $wgContentHandlerUseDB;
3870
3871                 $dbw = wfGetDB( DB_MASTER );
3872
3873                 # Is it a redirect?
3874                 $fields = [ 'page_is_redirect', 'page_latest', 'page_id' ];
3875                 if ( $wgContentHandlerUseDB ) {
3876                         $fields[] = 'page_content_model';
3877                 }
3878
3879                 $row = $dbw->selectRow( 'page',
3880                         $fields,
3881                         $this->pageCond(),
3882                         __METHOD__,
3883                         [ 'FOR UPDATE' ]
3884                 );
3885                 # Cache some fields we may want
3886                 $this->mArticleID = $row ? intval( $row->page_id ) : 0;
3887                 $this->mRedirect = $row ? (bool)$row->page_is_redirect : false;
3888                 $this->mLatestID = $row ? intval( $row->page_latest ) : false;
3889                 $this->mContentModel = $row && isset( $row->page_content_model )
3890                         ? strval( $row->page_content_model )
3891                         : false;
3892
3893                 if ( !$this->mRedirect ) {
3894                         return false;
3895                 }
3896                 # Does the article have a history?
3897                 $row = $dbw->selectField( [ 'page', 'revision' ],
3898                         'rev_id',
3899                         [ 'page_namespace' => $this->getNamespace(),
3900                                 'page_title' => $this->getDBkey(),
3901                                 'page_id=rev_page',
3902                                 'page_latest != rev_id'
3903                         ],
3904                         __METHOD__,
3905                         [ 'FOR UPDATE' ]
3906                 );
3907                 # Return true if there was no history
3908                 return ( $row === false );
3909         }
3910
3911         /**
3912          * Checks if $this can be moved to a given Title
3913          * - Selects for update, so don't call it unless you mean business
3914          *
3915          * @deprecated since 1.25, use MovePage's methods instead
3916          * @param Title $nt The new title to check
3917          * @return bool
3918          */
3919         public function isValidMoveTarget( $nt ) {
3920                 # Is it an existing file?
3921                 if ( $nt->getNamespace() == NS_FILE ) {
3922                         $file = wfLocalFile( $nt );
3923                         $file->load( File::READ_LATEST );
3924                         if ( $file->exists() ) {
3925                                 wfDebug( __METHOD__ . ": file exists\n" );
3926                                 return false;
3927                         }
3928                 }
3929                 # Is it a redirect with no history?
3930                 if ( !$nt->isSingleRevRedirect() ) {
3931                         wfDebug( __METHOD__ . ": not a one-rev redirect\n" );
3932                         return false;
3933                 }
3934                 # Get the article text
3935                 $rev = Revision::newFromTitle( $nt, false, Revision::READ_LATEST );
3936                 if ( !is_object( $rev ) ) {
3937                         return false;
3938                 }
3939                 $content = $rev->getContent();
3940                 # Does the redirect point to the source?
3941                 # Or is it a broken self-redirect, usually caused by namespace collisions?
3942                 $redirTitle = $content ? $content->getRedirectTarget() : null;
3943
3944                 if ( $redirTitle ) {
3945                         if ( $redirTitle->getPrefixedDBkey() != $this->getPrefixedDBkey() &&
3946                                 $redirTitle->getPrefixedDBkey() != $nt->getPrefixedDBkey() ) {
3947                                 wfDebug( __METHOD__ . ": redirect points to other page\n" );
3948                                 return false;
3949                         } else {
3950                                 return true;
3951                         }
3952                 } else {
3953                         # Fail safe (not a redirect after all. strange.)
3954                         wfDebug( __METHOD__ . ": failsafe: database sais " . $nt->getPrefixedDBkey() .
3955                                                 " is a redirect, but it doesn't contain a valid redirect.\n" );
3956                         return false;
3957                 }
3958         }
3959
3960         /**
3961          * Get categories to which this Title belongs and return an array of
3962          * categories' names.
3963          *
3964          * @return array Array of parents in the form:
3965          *     $parent => $currentarticle
3966          */
3967         public function getParentCategories() {
3968                 global $wgContLang;
3969
3970                 $data = [];
3971
3972                 $titleKey = $this->getArticleID();
3973
3974                 if ( $titleKey === 0 ) {
3975                         return $data;
3976                 }
3977
3978                 $dbr = wfGetDB( DB_REPLICA );
3979
3980                 $res = $dbr->select(
3981                         'categorylinks',
3982                         'cl_to',
3983                         [ 'cl_from' => $titleKey ],
3984                         __METHOD__
3985                 );
3986
3987                 if ( $res->numRows() > 0 ) {
3988                         foreach ( $res as $row ) {
3989                                 // $data[] = Title::newFromText($wgContLang->getNsText ( NS_CATEGORY ).':'.$row->cl_to);
3990                                 $data[$wgContLang->getNsText( NS_CATEGORY ) . ':' . $row->cl_to] = $this->getFullText();
3991                         }
3992                 }
3993                 return $data;
3994         }
3995
3996         /**
3997          * Get a tree of parent categories
3998          *
3999          * @param array $children Array with the children in the keys, to check for circular refs
4000          * @return array Tree of parent categories
4001          */
4002         public function getParentCategoryTree( $children = [] ) {
4003                 $stack = [];
4004                 $parents = $this->getParentCategories();
4005
4006                 if ( $parents ) {
4007                         foreach ( $parents as $parent => $current ) {
4008                                 if ( array_key_exists( $parent, $children ) ) {
4009                                         # Circular reference
4010                                         $stack[$parent] = [];
4011                                 } else {
4012                                         $nt = self::newFromText( $parent );
4013                                         if ( $nt ) {
4014                                                 $stack[$parent] = $nt->getParentCategoryTree( $children + [ $parent => 1 ] );
4015                                         }
4016                                 }
4017                         }
4018                 }
4019
4020                 return $stack;
4021         }
4022
4023         /**
4024          * Get an associative array for selecting this title from
4025          * the "page" table
4026          *
4027          * @return array Array suitable for the $where parameter of DB::select()
4028          */
4029         public function pageCond() {
4030                 if ( $this->mArticleID > 0 ) {
4031                         // PK avoids secondary lookups in InnoDB, shouldn't hurt other DBs
4032                         return [ 'page_id' => $this->mArticleID ];
4033                 } else {
4034                         return [ 'page_namespace' => $this->mNamespace, 'page_title' => $this->mDbkeyform ];
4035                 }
4036         }
4037
4038         /**
4039          * Get next/previous revision ID relative to another revision ID
4040          * @param int $revId Revision ID. Get the revision that was before this one.
4041          * @param int $flags Title::GAID_FOR_UPDATE
4042          * @param string $dir 'next' or 'prev'
4043          * @return int|bool New revision ID, or false if none exists
4044          */
4045         private function getRelativeRevisionID( $revId, $flags, $dir ) {
4046                 $revId = (int)$revId;
4047                 if ( $dir === 'next' ) {
4048                         $op = '>';
4049                         $sort = 'ASC';
4050                 } elseif ( $dir === 'prev' ) {
4051                         $op = '<';
4052                         $sort = 'DESC';
4053                 } else {
4054                         throw new InvalidArgumentException( '$dir must be "next" or "prev"' );
4055                 }
4056
4057                 if ( $flags & self::GAID_FOR_UPDATE ) {
4058                         $db = wfGetDB( DB_MASTER );
4059                 } else {
4060                         $db = wfGetDB( DB_REPLICA, 'contributions' );
4061                 }
4062
4063                 // Intentionally not caring if the specified revision belongs to this
4064                 // page. We only care about the timestamp.
4065                 $ts = $db->selectField( 'revision', 'rev_timestamp', [ 'rev_id' => $revId ], __METHOD__ );
4066                 if ( $ts === false ) {
4067                         $ts = $db->selectField( 'archive', 'ar_timestamp', [ 'ar_rev_id' => $revId ], __METHOD__ );
4068                         if ( $ts === false ) {
4069                                 // Or should this throw an InvalidArgumentException or something?
4070                                 return false;
4071                         }
4072                 }
4073                 $ts = $db->addQuotes( $ts );
4074
4075                 $revId = $db->selectField( 'revision', 'rev_id',
4076                         [
4077                                 'rev_page' => $this->getArticleID( $flags ),
4078                                 "rev_timestamp $op $ts OR (rev_timestamp = $ts AND rev_id $op $revId)"
4079                         ],
4080                         __METHOD__,
4081                         [
4082                                 'ORDER BY' => "rev_timestamp $sort, rev_id $sort",
4083                                 'IGNORE INDEX' => 'rev_timestamp', // Probably needed for T159319
4084                         ]
4085                 );
4086
4087                 if ( $revId === false ) {
4088                         return false;
4089                 } else {
4090                         return intval( $revId );
4091                 }
4092         }
4093
4094         /**
4095          * Get the revision ID of the previous revision
4096          *
4097          * @param int $revId Revision ID. Get the revision that was before this one.
4098          * @param int $flags Title::GAID_FOR_UPDATE
4099          * @return int|bool Old revision ID, or false if none exists
4100          */
4101         public function getPreviousRevisionID( $revId, $flags = 0 ) {
4102                 return $this->getRelativeRevisionID( $revId, $flags, 'prev' );
4103         }
4104
4105         /**
4106          * Get the revision ID of the next revision
4107          *
4108          * @param int $revId Revision ID. Get the revision that was after this one.
4109          * @param int $flags Title::GAID_FOR_UPDATE
4110          * @return int|bool Next revision ID, or false if none exists
4111          */
4112         public function getNextRevisionID( $revId, $flags = 0 ) {
4113                 return $this->getRelativeRevisionID( $revId, $flags, 'next' );
4114         }
4115
4116         /**
4117          * Get the first revision of the page
4118          *
4119          * @param int $flags Title::GAID_FOR_UPDATE
4120          * @return Revision|null If page doesn't exist
4121          */
4122         public function getFirstRevision( $flags = 0 ) {
4123                 $pageId = $this->getArticleID( $flags );
4124                 if ( $pageId ) {
4125                         $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_REPLICA );
4126                         $row = $db->selectRow( 'revision', Revision::selectFields(),
4127                                 [ 'rev_page' => $pageId ],
4128                                 __METHOD__,
4129                                 [
4130                                         'ORDER BY' => 'rev_timestamp ASC, rev_id ASC',
4131                                         'IGNORE INDEX' => 'rev_timestamp', // See T159319
4132                                 ]
4133                         );
4134                         if ( $row ) {
4135                                 return new Revision( $row );
4136                         }
4137                 }
4138                 return null;
4139         }
4140
4141         /**
4142          * Get the oldest revision timestamp of this page
4143          *
4144          * @param int $flags Title::GAID_FOR_UPDATE
4145          * @return string MW timestamp
4146          */
4147         public function getEarliestRevTime( $flags = 0 ) {
4148                 $rev = $this->getFirstRevision( $flags );
4149                 return $rev ? $rev->getTimestamp() : null;
4150         }
4151
4152         /**
4153          * Check if this is a new page
4154          *
4155          * @return bool
4156          */
4157         public function isNewPage() {
4158                 $dbr = wfGetDB( DB_REPLICA );
4159                 return (bool)$dbr->selectField( 'page', 'page_is_new', $this->pageCond(), __METHOD__ );
4160         }
4161
4162         /**
4163          * Check whether the number of revisions of this page surpasses $wgDeleteRevisionsLimit
4164          *
4165          * @return bool
4166          */
4167         public function isBigDeletion() {
4168                 global $wgDeleteRevisionsLimit;
4169
4170                 if ( !$wgDeleteRevisionsLimit ) {
4171                         return false;
4172                 }
4173
4174                 if ( $this->mIsBigDeletion === null ) {
4175                         $dbr = wfGetDB( DB_REPLICA );
4176
4177                         $revCount = $dbr->selectRowCount(
4178                                 'revision',
4179                                 '1',
4180                                 [ 'rev_page' => $this->getArticleID() ],
4181                                 __METHOD__,
4182                                 [ 'LIMIT' => $wgDeleteRevisionsLimit + 1 ]
4183                         );
4184
4185                         $this->mIsBigDeletion = $revCount > $wgDeleteRevisionsLimit;
4186                 }
4187
4188                 return $this->mIsBigDeletion;
4189         }
4190
4191         /**
4192          * Get the approximate revision count of this page.
4193          *
4194          * @return int
4195          */
4196         public function estimateRevisionCount() {
4197                 if ( !$this->exists() ) {
4198                         return 0;
4199                 }
4200
4201                 if ( $this->mEstimateRevisions === null ) {
4202                         $dbr = wfGetDB( DB_REPLICA );
4203                         $this->mEstimateRevisions = $dbr->estimateRowCount( 'revision', '*',
4204                                 [ 'rev_page' => $this->getArticleID() ], __METHOD__ );
4205                 }
4206
4207                 return $this->mEstimateRevisions;
4208         }
4209
4210         /**
4211          * Get the number of revisions between the given revision.
4212          * Used for diffs and other things that really need it.
4213          *
4214          * @param int|Revision $old Old revision or rev ID (first before range)
4215          * @param int|Revision $new New revision or rev ID (first after range)
4216          * @param int|null $max Limit of Revisions to count, will be incremented to detect truncations
4217          * @return int Number of revisions between these revisions.
4218          */
4219         public function countRevisionsBetween( $old, $new, $max = null ) {
4220                 if ( !( $old instanceof Revision ) ) {
4221                         $old = Revision::newFromTitle( $this, (int)$old );
4222                 }
4223                 if ( !( $new instanceof Revision ) ) {
4224                         $new = Revision::newFromTitle( $this, (int)$new );
4225                 }
4226                 if ( !$old || !$new ) {
4227                         return 0; // nothing to compare
4228                 }
4229                 $dbr = wfGetDB( DB_REPLICA );
4230                 $conds = [
4231                         'rev_page' => $this->getArticleID(),
4232                         'rev_timestamp > ' . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4233                         'rev_timestamp < ' . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4234                 ];
4235                 if ( $max !== null ) {
4236                         return $dbr->selectRowCount( 'revision', '1',
4237                                 $conds,
4238                                 __METHOD__,
4239                                 [ 'LIMIT' => $max + 1 ] // extra to detect truncation
4240                         );
4241                 } else {
4242                         return (int)$dbr->selectField( 'revision', 'count(*)', $conds, __METHOD__ );
4243                 }
4244         }
4245
4246         /**
4247          * Get the authors between the given revisions or revision IDs.
4248          * Used for diffs and other things that really need it.
4249          *
4250          * @since 1.23
4251          *
4252          * @param int|Revision $old Old revision or rev ID (first before range by default)
4253          * @param int|Revision $new New revision or rev ID (first after range by default)
4254          * @param int $limit Maximum number of authors
4255          * @param string|array $options (Optional): Single option, or an array of options:
4256          *     'include_old' Include $old in the range; $new is excluded.
4257          *     'include_new' Include $new in the range; $old is excluded.
4258          *     'include_both' Include both $old and $new in the range.
4259          *     Unknown option values are ignored.
4260          * @return array|null Names of revision authors in the range; null if not both revisions exist
4261          */
4262         public function getAuthorsBetween( $old, $new, $limit, $options = [] ) {
4263                 if ( !( $old instanceof Revision ) ) {
4264                         $old = Revision::newFromTitle( $this, (int)$old );
4265                 }
4266                 if ( !( $new instanceof Revision ) ) {
4267                         $new = Revision::newFromTitle( $this, (int)$new );
4268                 }
4269                 // XXX: what if Revision objects are passed in, but they don't refer to this title?
4270                 // Add $old->getPage() != $new->getPage() || $old->getPage() != $this->getArticleID()
4271                 // in the sanity check below?
4272                 if ( !$old || !$new ) {
4273                         return null; // nothing to compare
4274                 }
4275                 $authors = [];
4276                 $old_cmp = '>';
4277                 $new_cmp = '<';
4278                 $options = (array)$options;
4279                 if ( in_array( 'include_old', $options ) ) {
4280                         $old_cmp = '>=';
4281                 }
4282                 if ( in_array( 'include_new', $options ) ) {
4283                         $new_cmp = '<=';
4284                 }
4285                 if ( in_array( 'include_both', $options ) ) {
4286                         $old_cmp = '>=';
4287                         $new_cmp = '<=';
4288                 }
4289                 // No DB query needed if $old and $new are the same or successive revisions:
4290                 if ( $old->getId() === $new->getId() ) {
4291                         return ( $old_cmp === '>' && $new_cmp === '<' ) ?
4292                                 [] :
4293                                 [ $old->getUserText( Revision::RAW ) ];
4294                 } elseif ( $old->getId() === $new->getParentId() ) {
4295                         if ( $old_cmp === '>=' && $new_cmp === '<=' ) {
4296                                 $authors[] = $old->getUserText( Revision::RAW );
4297                                 if ( $old->getUserText( Revision::RAW ) != $new->getUserText( Revision::RAW ) ) {
4298                                         $authors[] = $new->getUserText( Revision::RAW );
4299                                 }
4300                         } elseif ( $old_cmp === '>=' ) {
4301                                 $authors[] = $old->getUserText( Revision::RAW );
4302                         } elseif ( $new_cmp === '<=' ) {
4303                                 $authors[] = $new->getUserText( Revision::RAW );
4304                         }
4305                         return $authors;
4306                 }
4307                 $dbr = wfGetDB( DB_REPLICA );
4308                 $res = $dbr->select( 'revision', 'DISTINCT rev_user_text',
4309                         [
4310                                 'rev_page' => $this->getArticleID(),
4311                                 "rev_timestamp $old_cmp " . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4312                                 "rev_timestamp $new_cmp " . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4313                         ], __METHOD__,
4314                         [ 'LIMIT' => $limit + 1 ] // add one so caller knows it was truncated
4315                 );
4316                 foreach ( $res as $row ) {
4317                         $authors[] = $row->rev_user_text;
4318                 }
4319                 return $authors;
4320         }
4321
4322         /**
4323          * Get the number of authors between the given revisions or revision IDs.
4324          * Used for diffs and other things that really need it.
4325          *
4326          * @param int|Revision $old Old revision or rev ID (first before range by default)
4327          * @param int|Revision $new New revision or rev ID (first after range by default)
4328          * @param int $limit Maximum number of authors
4329          * @param string|array $options (Optional): Single option, or an array of options:
4330          *     'include_old' Include $old in the range; $new is excluded.
4331          *     'include_new' Include $new in the range; $old is excluded.
4332          *     'include_both' Include both $old and $new in the range.
4333          *     Unknown option values are ignored.
4334          * @return int Number of revision authors in the range; zero if not both revisions exist
4335          */
4336         public function countAuthorsBetween( $old, $new, $limit, $options = [] ) {
4337                 $authors = $this->getAuthorsBetween( $old, $new, $limit, $options );
4338                 return $authors ? count( $authors ) : 0;
4339         }
4340
4341         /**
4342          * Compare with another title.
4343          *
4344          * @param Title $title
4345          * @return bool
4346          */
4347         public function equals( Title $title ) {
4348                 // Note: === is necessary for proper matching of number-like titles.
4349                 return $this->getInterwiki() === $title->getInterwiki()
4350                         && $this->getNamespace() == $title->getNamespace()
4351                         && $this->getDBkey() === $title->getDBkey();
4352         }
4353
4354         /**
4355          * Check if this title is a subpage of another title
4356          *
4357          * @param Title $title
4358          * @return bool
4359          */
4360         public function isSubpageOf( Title $title ) {
4361                 return $this->getInterwiki() === $title->getInterwiki()
4362                         && $this->getNamespace() == $title->getNamespace()
4363                         && strpos( $this->getDBkey(), $title->getDBkey() . '/' ) === 0;
4364         }
4365
4366         /**
4367          * Check if page exists.  For historical reasons, this function simply
4368          * checks for the existence of the title in the page table, and will
4369          * thus return false for interwiki links, special pages and the like.
4370          * If you want to know if a title can be meaningfully viewed, you should
4371          * probably call the isKnown() method instead.
4372          *
4373          * @param int $flags An optional bit field; may be Title::GAID_FOR_UPDATE to check
4374          *   from master/for update
4375          * @return bool
4376          */
4377         public function exists( $flags = 0 ) {
4378                 $exists = $this->getArticleID( $flags ) != 0;
4379                 Hooks::run( 'TitleExists', [ $this, &$exists ] );
4380                 return $exists;
4381         }
4382
4383         /**
4384          * Should links to this title be shown as potentially viewable (i.e. as
4385          * "bluelinks"), even if there's no record by this title in the page
4386          * table?
4387          *
4388          * This function is semi-deprecated for public use, as well as somewhat
4389          * misleadingly named.  You probably just want to call isKnown(), which
4390          * calls this function internally.
4391          *
4392          * (ISSUE: Most of these checks are cheap, but the file existence check
4393          * can potentially be quite expensive.  Including it here fixes a lot of
4394          * existing code, but we might want to add an optional parameter to skip
4395          * it and any other expensive checks.)
4396          *
4397          * @return bool
4398          */
4399         public function isAlwaysKnown() {
4400                 $isKnown = null;
4401
4402                 /**
4403                  * Allows overriding default behavior for determining if a page exists.
4404                  * If $isKnown is kept as null, regular checks happen. If it's
4405                  * a boolean, this value is returned by the isKnown method.
4406                  *
4407                  * @since 1.20
4408                  *
4409                  * @param Title $title
4410                  * @param bool|null $isKnown
4411                  */
4412                 Hooks::run( 'TitleIsAlwaysKnown', [ $this, &$isKnown ] );
4413
4414                 if ( !is_null( $isKnown ) ) {
4415                         return $isKnown;
4416                 }
4417
4418                 if ( $this->isExternal() ) {
4419                         return true;  // any interwiki link might be viewable, for all we know
4420                 }
4421
4422                 switch ( $this->mNamespace ) {
4423                         case NS_MEDIA:
4424                         case NS_FILE:
4425                                 // file exists, possibly in a foreign repo
4426                                 return (bool)wfFindFile( $this );
4427                         case NS_SPECIAL:
4428                                 // valid special page
4429                                 return SpecialPageFactory::exists( $this->getDBkey() );
4430                         case NS_MAIN:
4431                                 // selflink, possibly with fragment
4432                                 return $this->mDbkeyform == '';
4433                         case NS_MEDIAWIKI:
4434                                 // known system message
4435                                 return $this->hasSourceText() !== false;
4436                         default:
4437                                 return false;
4438                 }
4439         }
4440
4441         /**
4442          * Does this title refer to a page that can (or might) be meaningfully
4443          * viewed?  In particular, this function may be used to determine if
4444          * links to the title should be rendered as "bluelinks" (as opposed to
4445          * "redlinks" to non-existent pages).
4446          * Adding something else to this function will cause inconsistency
4447          * since LinkHolderArray calls isAlwaysKnown() and does its own
4448          * page existence check.
4449          *
4450          * @return bool
4451          */
4452         public function isKnown() {
4453                 return $this->isAlwaysKnown() || $this->exists();
4454         }
4455
4456         /**
4457          * Does this page have source text?
4458          *
4459          * @return bool
4460          */
4461         public function hasSourceText() {
4462                 if ( $this->exists() ) {
4463                         return true;
4464                 }
4465
4466                 if ( $this->mNamespace == NS_MEDIAWIKI ) {
4467                         // If the page doesn't exist but is a known system message, default
4468                         // message content will be displayed, same for language subpages-
4469                         // Use always content language to avoid loading hundreds of languages
4470                         // to get the link color.
4471                         global $wgContLang;
4472                         list( $name, ) = MessageCache::singleton()->figureMessage(
4473                                 $wgContLang->lcfirst( $this->getText() )
4474                         );
4475                         $message = wfMessage( $name )->inLanguage( $wgContLang )->useDatabase( false );
4476                         return $message->exists();
4477                 }
4478
4479                 return false;
4480         }
4481
4482         /**
4483          * Get the default message text or false if the message doesn't exist
4484          *
4485          * @return string|bool
4486          */
4487         public function getDefaultMessageText() {
4488                 global $wgContLang;
4489
4490                 if ( $this->getNamespace() != NS_MEDIAWIKI ) { // Just in case
4491                         return false;
4492                 }
4493
4494                 list( $name, $lang ) = MessageCache::singleton()->figureMessage(
4495                         $wgContLang->lcfirst( $this->getText() )
4496                 );
4497                 $message = wfMessage( $name )->inLanguage( $lang )->useDatabase( false );
4498
4499                 if ( $message->exists() ) {
4500                         return $message->plain();
4501                 } else {
4502                         return false;
4503                 }
4504         }
4505
4506         /**
4507          * Updates page_touched for this page; called from LinksUpdate.php
4508          *
4509          * @param string $purgeTime [optional] TS_MW timestamp
4510          * @return bool True if the update succeeded
4511          */
4512         public function invalidateCache( $purgeTime = null ) {
4513                 if ( wfReadOnly() ) {
4514                         return false;
4515                 } elseif ( $this->mArticleID === 0 ) {
4516                         return true; // avoid gap locking if we know it's not there
4517                 }
4518
4519                 $dbw = wfGetDB( DB_MASTER );
4520                 $dbw->onTransactionPreCommitOrIdle( function () {
4521                         ResourceLoaderWikiModule::invalidateModuleCache( $this, null, null, wfWikiID() );
4522                 } );
4523
4524                 $conds = $this->pageCond();
4525                 DeferredUpdates::addUpdate(
4526                         new AutoCommitUpdate(
4527                                 $dbw,
4528                                 __METHOD__,
4529                                 function ( IDatabase $dbw, $fname ) use ( $conds, $purgeTime ) {
4530                                         $dbTimestamp = $dbw->timestamp( $purgeTime ?: time() );
4531                                         $dbw->update(
4532                                                 'page',
4533                                                 [ 'page_touched' => $dbTimestamp ],
4534                                                 $conds + [ 'page_touched < ' . $dbw->addQuotes( $dbTimestamp ) ],
4535                                                 $fname
4536                                         );
4537                                         MediaWikiServices::getInstance()->getLinkCache()->invalidateTitle( $this );
4538                                 }
4539                         ),
4540                         DeferredUpdates::PRESEND
4541                 );
4542
4543                 return true;
4544         }
4545
4546         /**
4547          * Update page_touched timestamps and send CDN purge messages for
4548          * pages linking to this title. May be sent to the job queue depending
4549          * on the number of links. Typically called on create and delete.
4550          */
4551         public function touchLinks() {
4552                 DeferredUpdates::addUpdate( new HTMLCacheUpdate( $this, 'pagelinks' ) );
4553                 if ( $this->getNamespace() == NS_CATEGORY ) {
4554                         DeferredUpdates::addUpdate( new HTMLCacheUpdate( $this, 'categorylinks' ) );
4555                 }
4556         }
4557
4558         /**
4559          * Get the last touched timestamp
4560          *
4561          * @param IDatabase $db Optional db
4562          * @return string|false Last-touched timestamp
4563          */
4564         public function getTouched( $db = null ) {
4565                 if ( $db === null ) {
4566                         $db = wfGetDB( DB_REPLICA );
4567                 }
4568                 $touched = $db->selectField( 'page', 'page_touched', $this->pageCond(), __METHOD__ );
4569                 return $touched;
4570         }
4571
4572         /**
4573          * Get the timestamp when this page was updated since the user last saw it.
4574          *
4575          * @param User $user
4576          * @return string|null
4577          */
4578         public function getNotificationTimestamp( $user = null ) {
4579                 global $wgUser;
4580
4581                 // Assume current user if none given
4582                 if ( !$user ) {
4583                         $user = $wgUser;
4584                 }
4585                 // Check cache first
4586                 $uid = $user->getId();
4587                 if ( !$uid ) {
4588                         return false;
4589                 }
4590                 // avoid isset here, as it'll return false for null entries
4591                 if ( array_key_exists( $uid, $this->mNotificationTimestamp ) ) {
4592                         return $this->mNotificationTimestamp[$uid];
4593                 }
4594                 // Don't cache too much!
4595                 if ( count( $this->mNotificationTimestamp ) >= self::CACHE_MAX ) {
4596                         $this->mNotificationTimestamp = [];
4597                 }
4598
4599                 $store = MediaWikiServices::getInstance()->getWatchedItemStore();
4600                 $watchedItem = $store->getWatchedItem( $user, $this );
4601                 if ( $watchedItem ) {
4602                         $this->mNotificationTimestamp[$uid] = $watchedItem->getNotificationTimestamp();
4603                 } else {
4604                         $this->mNotificationTimestamp[$uid] = false;
4605                 }
4606
4607                 return $this->mNotificationTimestamp[$uid];
4608         }
4609
4610         /**
4611          * Generate strings used for xml 'id' names in monobook tabs
4612          *
4613          * @param string $prepend Defaults to 'nstab-'
4614          * @return string XML 'id' name
4615          */
4616         public function getNamespaceKey( $prepend = 'nstab-' ) {
4617                 global $wgContLang;
4618                 // Gets the subject namespace if this title
4619                 $namespace = MWNamespace::getSubject( $this->getNamespace() );
4620                 // Checks if canonical namespace name exists for namespace
4621                 if ( MWNamespace::exists( $this->getNamespace() ) ) {
4622                         // Uses canonical namespace name
4623                         $namespaceKey = MWNamespace::getCanonicalName( $namespace );
4624                 } else {
4625                         // Uses text of namespace
4626                         $namespaceKey = $this->getSubjectNsText();
4627                 }
4628                 // Makes namespace key lowercase
4629                 $namespaceKey = $wgContLang->lc( $namespaceKey );
4630                 // Uses main
4631                 if ( $namespaceKey == '' ) {
4632                         $namespaceKey = 'main';
4633                 }
4634                 // Changes file to image for backwards compatibility
4635                 if ( $namespaceKey == 'file' ) {
4636                         $namespaceKey = 'image';
4637                 }
4638                 return $prepend . $namespaceKey;
4639         }
4640
4641         /**
4642          * Get all extant redirects to this Title
4643          *
4644          * @param int|null $ns Single namespace to consider; null to consider all namespaces
4645          * @return Title[] Array of Title redirects to this title
4646          */
4647         public function getRedirectsHere( $ns = null ) {
4648                 $redirs = [];
4649
4650                 $dbr = wfGetDB( DB_REPLICA );
4651                 $where = [
4652                         'rd_namespace' => $this->getNamespace(),
4653                         'rd_title' => $this->getDBkey(),
4654                         'rd_from = page_id'
4655                 ];
4656                 if ( $this->isExternal() ) {
4657                         $where['rd_interwiki'] = $this->getInterwiki();
4658                 } else {
4659                         $where[] = 'rd_interwiki = ' . $dbr->addQuotes( '' ) . ' OR rd_interwiki IS NULL';
4660                 }
4661                 if ( !is_null( $ns ) ) {
4662                         $where['page_namespace'] = $ns;
4663                 }
4664
4665                 $res = $dbr->select(
4666                         [ 'redirect', 'page' ],
4667                         [ 'page_namespace', 'page_title' ],
4668                         $where,
4669                         __METHOD__
4670                 );
4671
4672                 foreach ( $res as $row ) {
4673                         $redirs[] = self::newFromRow( $row );
4674                 }
4675                 return $redirs;
4676         }
4677
4678         /**
4679          * Check if this Title is a valid redirect target
4680          *
4681          * @return bool
4682          */
4683         public function isValidRedirectTarget() {
4684                 global $wgInvalidRedirectTargets;
4685
4686                 if ( $this->isSpecialPage() ) {
4687                         // invalid redirect targets are stored in a global array, but explicitly disallow Userlogout here
4688                         if ( $this->isSpecial( 'Userlogout' ) ) {
4689                                 return false;
4690                         }
4691
4692                         foreach ( $wgInvalidRedirectTargets as $target ) {
4693                                 if ( $this->isSpecial( $target ) ) {
4694                                         return false;
4695                                 }
4696                         }
4697                 }
4698
4699                 return true;
4700         }
4701
4702         /**
4703          * Get a backlink cache object
4704          *
4705          * @return BacklinkCache
4706          */
4707         public function getBacklinkCache() {
4708                 return BacklinkCache::get( $this );
4709         }
4710
4711         /**
4712          * Whether the magic words __INDEX__ and __NOINDEX__ function for this page.
4713          *
4714          * @return bool
4715          */
4716         public function canUseNoindex() {
4717                 global $wgExemptFromUserRobotsControl;
4718
4719                 $bannedNamespaces = is_null( $wgExemptFromUserRobotsControl )
4720                         ? MWNamespace::getContentNamespaces()
4721                         : $wgExemptFromUserRobotsControl;
4722
4723                 return !in_array( $this->mNamespace, $bannedNamespaces );
4724         }
4725
4726         /**
4727          * Returns the raw sort key to be used for categories, with the specified
4728          * prefix.  This will be fed to Collation::getSortKey() to get a
4729          * binary sortkey that can be used for actual sorting.
4730          *
4731          * @param string $prefix The prefix to be used, specified using
4732          *   {{defaultsort:}} or like [[Category:Foo|prefix]].  Empty for no
4733          *   prefix.
4734          * @return string
4735          */
4736         public function getCategorySortkey( $prefix = '' ) {
4737                 $unprefixed = $this->getText();
4738
4739                 // Anything that uses this hook should only depend
4740                 // on the Title object passed in, and should probably
4741                 // tell the users to run updateCollations.php --force
4742                 // in order to re-sort existing category relations.
4743                 Hooks::run( 'GetDefaultSortkey', [ $this, &$unprefixed ] );
4744                 if ( $prefix !== '' ) {
4745                         # Separate with a line feed, so the unprefixed part is only used as
4746                         # a tiebreaker when two pages have the exact same prefix.
4747                         # In UCA, tab is the only character that can sort above LF
4748                         # so we strip both of them from the original prefix.
4749                         $prefix = strtr( $prefix, "\n\t", '  ' );
4750                         return "$prefix\n$unprefixed";
4751                 }
4752                 return $unprefixed;
4753         }
4754
4755         /**
4756          * Returns the page language code saved in the database, if $wgPageLanguageUseDB is set
4757          * to true in LocalSettings.php, otherwise returns false. If there is no language saved in
4758          * the db, it will return NULL.
4759          *
4760          * @return string|null|bool
4761          */
4762         private function getDbPageLanguageCode() {
4763                 global $wgPageLanguageUseDB;
4764
4765                 // check, if the page language could be saved in the database, and if so and
4766                 // the value is not requested already, lookup the page language using LinkCache
4767                 if ( $wgPageLanguageUseDB && $this->mDbPageLanguage === false ) {
4768                         $linkCache = LinkCache::singleton();
4769                         $linkCache->addLinkObj( $this );
4770                         $this->mDbPageLanguage = $linkCache->getGoodLinkFieldObj( $this, 'lang' );
4771                 }
4772
4773                 return $this->mDbPageLanguage;
4774         }
4775
4776         /**
4777          * Get the language in which the content of this page is written in
4778          * wikitext. Defaults to $wgContLang, but in certain cases it can be
4779          * e.g. $wgLang (such as special pages, which are in the user language).
4780          *
4781          * @since 1.18
4782          * @return Language
4783          */
4784         public function getPageLanguage() {
4785                 global $wgLang, $wgLanguageCode;
4786                 if ( $this->isSpecialPage() ) {
4787                         // special pages are in the user language
4788                         return $wgLang;
4789                 }
4790
4791                 // Checking if DB language is set
4792                 $dbPageLanguage = $this->getDbPageLanguageCode();
4793                 if ( $dbPageLanguage ) {
4794                         return wfGetLangObj( $dbPageLanguage );
4795                 }
4796
4797                 if ( !$this->mPageLanguage || $this->mPageLanguage[1] !== $wgLanguageCode ) {
4798                         // Note that this may depend on user settings, so the cache should
4799                         // be only per-request.
4800                         // NOTE: ContentHandler::getPageLanguage() may need to load the
4801                         // content to determine the page language!
4802                         // Checking $wgLanguageCode hasn't changed for the benefit of unit
4803                         // tests.
4804                         $contentHandler = ContentHandler::getForTitle( $this );
4805                         $langObj = $contentHandler->getPageLanguage( $this );
4806                         $this->mPageLanguage = [ $langObj->getCode(), $wgLanguageCode ];
4807                 } else {
4808                         $langObj = wfGetLangObj( $this->mPageLanguage[0] );
4809                 }
4810
4811                 return $langObj;
4812         }
4813
4814         /**
4815          * Get the language in which the content of this page is written when
4816          * viewed by user. Defaults to $wgContLang, but in certain cases it can be
4817          * e.g. $wgLang (such as special pages, which are in the user language).
4818          *
4819          * @since 1.20
4820          * @return Language
4821          */
4822         public function getPageViewLanguage() {
4823                 global $wgLang;
4824
4825                 if ( $this->isSpecialPage() ) {
4826                         // If the user chooses a variant, the content is actually
4827                         // in a language whose code is the variant code.
4828                         $variant = $wgLang->getPreferredVariant();
4829                         if ( $wgLang->getCode() !== $variant ) {
4830                                 return Language::factory( $variant );
4831                         }
4832
4833                         return $wgLang;
4834                 }
4835
4836                 // Checking if DB language is set
4837                 $dbPageLanguage = $this->getDbPageLanguageCode();
4838                 if ( $dbPageLanguage ) {
4839                         $pageLang = wfGetLangObj( $dbPageLanguage );
4840                         $variant = $pageLang->getPreferredVariant();
4841                         if ( $pageLang->getCode() !== $variant ) {
4842                                 $pageLang = Language::factory( $variant );
4843                         }
4844
4845                         return $pageLang;
4846                 }
4847
4848                 // @note Can't be cached persistently, depends on user settings.
4849                 // @note ContentHandler::getPageViewLanguage() may need to load the
4850                 //   content to determine the page language!
4851                 $contentHandler = ContentHandler::getForTitle( $this );
4852                 $pageLang = $contentHandler->getPageViewLanguage( $this );
4853                 return $pageLang;
4854         }
4855
4856         /**
4857          * Get a list of rendered edit notices for this page.
4858          *
4859          * Array is keyed by the original message key, and values are rendered using parseAsBlock, so
4860          * they will already be wrapped in paragraphs.
4861          *
4862          * @since 1.21
4863          * @param int $oldid Revision ID that's being edited
4864          * @return array
4865          */
4866         public function getEditNotices( $oldid = 0 ) {
4867                 $notices = [];
4868
4869                 // Optional notice for the entire namespace
4870                 $editnotice_ns = 'editnotice-' . $this->getNamespace();
4871                 $msg = wfMessage( $editnotice_ns );
4872                 if ( $msg->exists() ) {
4873                         $html = $msg->parseAsBlock();
4874                         // Edit notices may have complex logic, but output nothing (T91715)
4875                         if ( trim( $html ) !== '' ) {
4876                                 $notices[$editnotice_ns] = Html::rawElement(
4877                                         'div',
4878                                         [ 'class' => [
4879                                                 'mw-editnotice',
4880                                                 'mw-editnotice-namespace',
4881                                                 Sanitizer::escapeClass( "mw-$editnotice_ns" )
4882                                         ] ],
4883                                         $html
4884                                 );
4885                         }
4886                 }
4887
4888                 if ( MWNamespace::hasSubpages( $this->getNamespace() ) ) {
4889                         // Optional notice for page itself and any parent page
4890                         $parts = explode( '/', $this->getDBkey() );
4891                         $editnotice_base = $editnotice_ns;
4892                         while ( count( $parts ) > 0 ) {
4893                                 $editnotice_base .= '-' . array_shift( $parts );
4894                                 $msg = wfMessage( $editnotice_base );
4895                                 if ( $msg->exists() ) {
4896                                         $html = $msg->parseAsBlock();
4897                                         if ( trim( $html ) !== '' ) {
4898                                                 $notices[$editnotice_base] = Html::rawElement(
4899                                                         'div',
4900                                                         [ 'class' => [
4901                                                                 'mw-editnotice',
4902                                                                 'mw-editnotice-base',
4903                                                                 Sanitizer::escapeClass( "mw-$editnotice_base" )
4904                                                         ] ],
4905                                                         $html
4906                                                 );
4907                                         }
4908                                 }
4909                         }
4910                 } else {
4911                         // Even if there are no subpages in namespace, we still don't want "/" in MediaWiki message keys
4912                         $editnoticeText = $editnotice_ns . '-' . strtr( $this->getDBkey(), '/', '-' );
4913                         $msg = wfMessage( $editnoticeText );
4914                         if ( $msg->exists() ) {
4915                                 $html = $msg->parseAsBlock();
4916                                 if ( trim( $html ) !== '' ) {
4917                                         $notices[$editnoticeText] = Html::rawElement(
4918                                                 'div',
4919                                                 [ 'class' => [
4920                                                         'mw-editnotice',
4921                                                         'mw-editnotice-page',
4922                                                         Sanitizer::escapeClass( "mw-$editnoticeText" )
4923                                                 ] ],
4924                                                 $html
4925                                         );
4926                                 }
4927                         }
4928                 }
4929
4930                 Hooks::run( 'TitleGetEditNotices', [ $this, $oldid, &$notices ] );
4931                 return $notices;
4932         }
4933
4934         /**
4935          * @return array
4936          */
4937         public function __sleep() {
4938                 return [
4939                         'mNamespace',
4940                         'mDbkeyform',
4941                         'mFragment',
4942                         'mInterwiki',
4943                         'mLocalInterwiki',
4944                         'mUserCaseDBKey',
4945                         'mDefaultNamespace',
4946                 ];
4947         }
4948
4949         public function __wakeup() {
4950                 $this->mArticleID = ( $this->mNamespace >= 0 ) ? -1 : 0;
4951                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
4952                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
4953         }
4954
4955 }