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          * @param string $query
1900          * @param string|bool $query2
1901          * @return string The URL
1902          */
1903         public function getInternalURL( $query = '', $query2 = false ) {
1904                 global $wgInternalServer, $wgServer;
1905                 $query = self::fixUrlQueryArgs( $query, $query2 );
1906                 $server = $wgInternalServer !== false ? $wgInternalServer : $wgServer;
1907                 $url = wfExpandUrl( $server . $this->getLocalURL( $query ), PROTO_HTTP );
1908                 // Avoid PHP 7.1 warning from passing $this by reference
1909                 $titleRef = $this;
1910                 Hooks::run( 'GetInternalURL', [ &$titleRef, &$url, $query ] );
1911                 return $url;
1912         }
1913
1914         /**
1915          * Get the URL for a canonical link, for use in things like IRC and
1916          * e-mail notifications. Uses $wgCanonicalServer and the
1917          * GetCanonicalURL hook.
1918          *
1919          * NOTE: Unlike getInternalURL(), the canonical URL includes the fragment
1920          *
1921          * @see self::getLocalURL for the arguments.
1922          * @return string The URL
1923          * @since 1.18
1924          */
1925         public function getCanonicalURL( $query = '', $query2 = false ) {
1926                 $query = self::fixUrlQueryArgs( $query, $query2 );
1927                 $url = wfExpandUrl( $this->getLocalURL( $query ) . $this->getFragmentForURL(), PROTO_CANONICAL );
1928                 // Avoid PHP 7.1 warning from passing $this by reference
1929                 $titleRef = $this;
1930                 Hooks::run( 'GetCanonicalURL', [ &$titleRef, &$url, $query ] );
1931                 return $url;
1932         }
1933
1934         /**
1935          * Get the edit URL for this Title
1936          *
1937          * @return string The URL, or a null string if this is an interwiki link
1938          */
1939         public function getEditURL() {
1940                 if ( $this->isExternal() ) {
1941                         return '';
1942                 }
1943                 $s = $this->getLocalURL( 'action=edit' );
1944
1945                 return $s;
1946         }
1947
1948         /**
1949          * Can $user perform $action on this page?
1950          * This skips potentially expensive cascading permission checks
1951          * as well as avoids expensive error formatting
1952          *
1953          * Suitable for use for nonessential UI controls in common cases, but
1954          * _not_ for functional access control.
1955          *
1956          * May provide false positives, but should never provide a false negative.
1957          *
1958          * @param string $action Action that permission needs to be checked for
1959          * @param User $user User to check (since 1.19); $wgUser will be used if not provided.
1960          * @return bool
1961          */
1962         public function quickUserCan( $action, $user = null ) {
1963                 return $this->userCan( $action, $user, false );
1964         }
1965
1966         /**
1967          * Can $user perform $action on this page?
1968          *
1969          * @param string $action Action that permission needs to be checked for
1970          * @param User $user User to check (since 1.19); $wgUser will be used if not
1971          *   provided.
1972          * @param string $rigor Same format as Title::getUserPermissionsErrors()
1973          * @return bool
1974          */
1975         public function userCan( $action, $user = null, $rigor = 'secure' ) {
1976                 if ( !$user instanceof User ) {
1977                         global $wgUser;
1978                         $user = $wgUser;
1979                 }
1980
1981                 return !count( $this->getUserPermissionsErrorsInternal( $action, $user, $rigor, true ) );
1982         }
1983
1984         /**
1985          * Can $user perform $action on this page?
1986          *
1987          * @todo FIXME: This *does not* check throttles (User::pingLimiter()).
1988          *
1989          * @param string $action Action that permission needs to be checked for
1990          * @param User $user User to check
1991          * @param string $rigor One of (quick,full,secure)
1992          *   - quick  : does cheap permission checks from replica DBs (usable for GUI creation)
1993          *   - full   : does cheap and expensive checks possibly from a replica DB
1994          *   - secure : does cheap and expensive checks, using the master as needed
1995          * @param array $ignoreErrors Array of Strings Set this to a list of message keys
1996          *   whose corresponding errors may be ignored.
1997          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
1998          */
1999         public function getUserPermissionsErrors(
2000                 $action, $user, $rigor = 'secure', $ignoreErrors = []
2001         ) {
2002                 $errors = $this->getUserPermissionsErrorsInternal( $action, $user, $rigor );
2003
2004                 // Remove the errors being ignored.
2005                 foreach ( $errors as $index => $error ) {
2006                         $errKey = is_array( $error ) ? $error[0] : $error;
2007
2008                         if ( in_array( $errKey, $ignoreErrors ) ) {
2009                                 unset( $errors[$index] );
2010                         }
2011                         if ( $errKey instanceof MessageSpecifier && in_array( $errKey->getKey(), $ignoreErrors ) ) {
2012                                 unset( $errors[$index] );
2013                         }
2014                 }
2015
2016                 return $errors;
2017         }
2018
2019         /**
2020          * Permissions checks that fail most often, and which are easiest to test.
2021          *
2022          * @param string $action The action to check
2023          * @param User $user User to check
2024          * @param array $errors List of current errors
2025          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2026          * @param bool $short Short circuit on first error
2027          *
2028          * @return array List of errors
2029          */
2030         private function checkQuickPermissions( $action, $user, $errors, $rigor, $short ) {
2031                 if ( !Hooks::run( 'TitleQuickPermissions',
2032                         [ $this, $user, $action, &$errors, ( $rigor !== 'quick' ), $short ] )
2033                 ) {
2034                         return $errors;
2035                 }
2036
2037                 if ( $action == 'create' ) {
2038                         if (
2039                                 ( $this->isTalkPage() && !$user->isAllowed( 'createtalk' ) ) ||
2040                                 ( !$this->isTalkPage() && !$user->isAllowed( 'createpage' ) )
2041                         ) {
2042                                 $errors[] = $user->isAnon() ? [ 'nocreatetext' ] : [ 'nocreate-loggedin' ];
2043                         }
2044                 } elseif ( $action == 'move' ) {
2045                         if ( !$user->isAllowed( 'move-rootuserpages' )
2046                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
2047                                 // Show user page-specific message only if the user can move other pages
2048                                 $errors[] = [ 'cant-move-user-page' ];
2049                         }
2050
2051                         // Check if user is allowed to move files if it's a file
2052                         if ( $this->mNamespace == NS_FILE && !$user->isAllowed( 'movefile' ) ) {
2053                                 $errors[] = [ 'movenotallowedfile' ];
2054                         }
2055
2056                         // Check if user is allowed to move category pages if it's a category page
2057                         if ( $this->mNamespace == NS_CATEGORY && !$user->isAllowed( 'move-categorypages' ) ) {
2058                                 $errors[] = [ 'cant-move-category-page' ];
2059                         }
2060
2061                         if ( !$user->isAllowed( 'move' ) ) {
2062                                 // User can't move anything
2063                                 $userCanMove = User::groupHasPermission( 'user', 'move' );
2064                                 $autoconfirmedCanMove = User::groupHasPermission( 'autoconfirmed', 'move' );
2065                                 if ( $user->isAnon() && ( $userCanMove || $autoconfirmedCanMove ) ) {
2066                                         // custom message if logged-in users without any special rights can move
2067                                         $errors[] = [ 'movenologintext' ];
2068                                 } else {
2069                                         $errors[] = [ 'movenotallowed' ];
2070                                 }
2071                         }
2072                 } elseif ( $action == 'move-target' ) {
2073                         if ( !$user->isAllowed( 'move' ) ) {
2074                                 // User can't move anything
2075                                 $errors[] = [ 'movenotallowed' ];
2076                         } elseif ( !$user->isAllowed( 'move-rootuserpages' )
2077                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
2078                                 // Show user page-specific message only if the user can move other pages
2079                                 $errors[] = [ 'cant-move-to-user-page' ];
2080                         } elseif ( !$user->isAllowed( 'move-categorypages' )
2081                                         && $this->mNamespace == NS_CATEGORY ) {
2082                                 // Show category page-specific message only if the user can move other pages
2083                                 $errors[] = [ 'cant-move-to-category-page' ];
2084                         }
2085                 } elseif ( !$user->isAllowed( $action ) ) {
2086                         $errors[] = $this->missingPermissionError( $action, $short );
2087                 }
2088
2089                 return $errors;
2090         }
2091
2092         /**
2093          * Add the resulting error code to the errors array
2094          *
2095          * @param array $errors List of current errors
2096          * @param array $result Result of errors
2097          *
2098          * @return array List of errors
2099          */
2100         private function resultToError( $errors, $result ) {
2101                 if ( is_array( $result ) && count( $result ) && !is_array( $result[0] ) ) {
2102                         // A single array representing an error
2103                         $errors[] = $result;
2104                 } elseif ( is_array( $result ) && is_array( $result[0] ) ) {
2105                         // A nested array representing multiple errors
2106                         $errors = array_merge( $errors, $result );
2107                 } elseif ( $result !== '' && is_string( $result ) ) {
2108                         // A string representing a message-id
2109                         $errors[] = [ $result ];
2110                 } elseif ( $result instanceof MessageSpecifier ) {
2111                         // A message specifier representing an error
2112                         $errors[] = [ $result ];
2113                 } elseif ( $result === false ) {
2114                         // a generic "We don't want them to do that"
2115                         $errors[] = [ 'badaccess-group0' ];
2116                 }
2117                 return $errors;
2118         }
2119
2120         /**
2121          * Check various permission hooks
2122          *
2123          * @param string $action The action to check
2124          * @param User $user User to check
2125          * @param array $errors List of current errors
2126          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2127          * @param bool $short Short circuit on first error
2128          *
2129          * @return array List of errors
2130          */
2131         private function checkPermissionHooks( $action, $user, $errors, $rigor, $short ) {
2132                 // Use getUserPermissionsErrors instead
2133                 $result = '';
2134                 // Avoid PHP 7.1 warning from passing $this by reference
2135                 $titleRef = $this;
2136                 if ( !Hooks::run( 'userCan', [ &$titleRef, &$user, $action, &$result ] ) ) {
2137                         return $result ? [] : [ [ 'badaccess-group0' ] ];
2138                 }
2139                 // Check getUserPermissionsErrors hook
2140                 // Avoid PHP 7.1 warning from passing $this by reference
2141                 $titleRef = $this;
2142                 if ( !Hooks::run( 'getUserPermissionsErrors', [ &$titleRef, &$user, $action, &$result ] ) ) {
2143                         $errors = $this->resultToError( $errors, $result );
2144                 }
2145                 // Check getUserPermissionsErrorsExpensive hook
2146                 if (
2147                         $rigor !== 'quick'
2148                         && !( $short && count( $errors ) > 0 )
2149                         && !Hooks::run( 'getUserPermissionsErrorsExpensive', [ &$titleRef, &$user, $action, &$result ] )
2150                 ) {
2151                         $errors = $this->resultToError( $errors, $result );
2152                 }
2153
2154                 return $errors;
2155         }
2156
2157         /**
2158          * Check permissions on special pages & namespaces
2159          *
2160          * @param string $action The action to check
2161          * @param User $user User to check
2162          * @param array $errors List of current errors
2163          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2164          * @param bool $short Short circuit on first error
2165          *
2166          * @return array List of errors
2167          */
2168         private function checkSpecialsAndNSPermissions( $action, $user, $errors, $rigor, $short ) {
2169                 # Only 'createaccount' can be performed on special pages,
2170                 # which don't actually exist in the DB.
2171                 if ( $this->isSpecialPage() && $action !== 'createaccount' ) {
2172                         $errors[] = [ 'ns-specialprotected' ];
2173                 }
2174
2175                 # Check $wgNamespaceProtection for restricted namespaces
2176                 if ( $this->isNamespaceProtected( $user ) ) {
2177                         $ns = $this->mNamespace == NS_MAIN ?
2178                                 wfMessage( 'nstab-main' )->text() : $this->getNsText();
2179                         $errors[] = $this->mNamespace == NS_MEDIAWIKI ?
2180                                 [ 'protectedinterface', $action ] : [ 'namespaceprotected', $ns, $action ];
2181                 }
2182
2183                 return $errors;
2184         }
2185
2186         /**
2187          * Check CSS/JS sub-page permissions
2188          *
2189          * @param string $action The action to check
2190          * @param User $user User to check
2191          * @param array $errors List of current errors
2192          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2193          * @param bool $short Short circuit on first error
2194          *
2195          * @return array List of errors
2196          */
2197         private function checkCSSandJSPermissions( $action, $user, $errors, $rigor, $short ) {
2198                 # Protect css/js subpages of user pages
2199                 # XXX: this might be better using restrictions
2200                 if ( $action != 'patrol' ) {
2201                         if ( preg_match( '/^' . preg_quote( $user->getName(), '/' ) . '\//', $this->mTextform ) ) {
2202                                 if ( $this->isCssSubpage() && !$user->isAllowedAny( 'editmyusercss', 'editusercss' ) ) {
2203                                         $errors[] = [ 'mycustomcssprotected', $action ];
2204                                 } elseif ( $this->isJsSubpage() && !$user->isAllowedAny( 'editmyuserjs', 'edituserjs' ) ) {
2205                                         $errors[] = [ 'mycustomjsprotected', $action ];
2206                                 }
2207                         } else {
2208                                 if ( $this->isCssSubpage() && !$user->isAllowed( 'editusercss' ) ) {
2209                                         $errors[] = [ 'customcssprotected', $action ];
2210                                 } elseif ( $this->isJsSubpage() && !$user->isAllowed( 'edituserjs' ) ) {
2211                                         $errors[] = [ 'customjsprotected', $action ];
2212                                 }
2213                         }
2214                 }
2215
2216                 return $errors;
2217         }
2218
2219         /**
2220          * Check against page_restrictions table requirements on this
2221          * page. The user must possess all required rights for this
2222          * action.
2223          *
2224          * @param string $action The action to check
2225          * @param User $user User to check
2226          * @param array $errors List of current errors
2227          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2228          * @param bool $short Short circuit on first error
2229          *
2230          * @return array List of errors
2231          */
2232         private function checkPageRestrictions( $action, $user, $errors, $rigor, $short ) {
2233                 foreach ( $this->getRestrictions( $action ) as $right ) {
2234                         // Backwards compatibility, rewrite sysop -> editprotected
2235                         if ( $right == 'sysop' ) {
2236                                 $right = 'editprotected';
2237                         }
2238                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2239                         if ( $right == 'autoconfirmed' ) {
2240                                 $right = 'editsemiprotected';
2241                         }
2242                         if ( $right == '' ) {
2243                                 continue;
2244                         }
2245                         if ( !$user->isAllowed( $right ) ) {
2246                                 $errors[] = [ 'protectedpagetext', $right, $action ];
2247                         } elseif ( $this->mCascadeRestriction && !$user->isAllowed( 'protect' ) ) {
2248                                 $errors[] = [ 'protectedpagetext', 'protect', $action ];
2249                         }
2250                 }
2251
2252                 return $errors;
2253         }
2254
2255         /**
2256          * Check restrictions on cascading pages.
2257          *
2258          * @param string $action The action to check
2259          * @param User $user User to check
2260          * @param array $errors List of current errors
2261          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2262          * @param bool $short Short circuit on first error
2263          *
2264          * @return array List of errors
2265          */
2266         private function checkCascadingSourcesRestrictions( $action, $user, $errors, $rigor, $short ) {
2267                 if ( $rigor !== 'quick' && !$this->isCssJsSubpage() ) {
2268                         # We /could/ use the protection level on the source page, but it's
2269                         # fairly ugly as we have to establish a precedence hierarchy for pages
2270                         # included by multiple cascade-protected pages. So just restrict
2271                         # it to people with 'protect' permission, as they could remove the
2272                         # protection anyway.
2273                         list( $cascadingSources, $restrictions ) = $this->getCascadeProtectionSources();
2274                         # Cascading protection depends on more than this page...
2275                         # Several cascading protected pages may include this page...
2276                         # Check each cascading level
2277                         # This is only for protection restrictions, not for all actions
2278                         if ( isset( $restrictions[$action] ) ) {
2279                                 foreach ( $restrictions[$action] as $right ) {
2280                                         // Backwards compatibility, rewrite sysop -> editprotected
2281                                         if ( $right == 'sysop' ) {
2282                                                 $right = 'editprotected';
2283                                         }
2284                                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2285                                         if ( $right == 'autoconfirmed' ) {
2286                                                 $right = 'editsemiprotected';
2287                                         }
2288                                         if ( $right != '' && !$user->isAllowedAll( 'protect', $right ) ) {
2289                                                 $pages = '';
2290                                                 foreach ( $cascadingSources as $page ) {
2291                                                         $pages .= '* [[:' . $page->getPrefixedText() . "]]\n";
2292                                                 }
2293                                                 $errors[] = [ 'cascadeprotected', count( $cascadingSources ), $pages, $action ];
2294                                         }
2295                                 }
2296                         }
2297                 }
2298
2299                 return $errors;
2300         }
2301
2302         /**
2303          * Check action permissions not already checked in checkQuickPermissions
2304          *
2305          * @param string $action The action to check
2306          * @param User $user User to check
2307          * @param array $errors List of current errors
2308          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2309          * @param bool $short Short circuit on first error
2310          *
2311          * @return array List of errors
2312          */
2313         private function checkActionPermissions( $action, $user, $errors, $rigor, $short ) {
2314                 global $wgDeleteRevisionsLimit, $wgLang;
2315
2316                 if ( $action == 'protect' ) {
2317                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit', $user, $rigor, true ) ) ) {
2318                                 // If they can't edit, they shouldn't protect.
2319                                 $errors[] = [ 'protect-cantedit' ];
2320                         }
2321                 } elseif ( $action == 'create' ) {
2322                         $title_protection = $this->getTitleProtection();
2323                         if ( $title_protection ) {
2324                                 if ( $title_protection['permission'] == ''
2325                                         || !$user->isAllowed( $title_protection['permission'] )
2326                                 ) {
2327                                         $errors[] = [
2328                                                 'titleprotected',
2329                                                 User::whoIs( $title_protection['user'] ),
2330                                                 $title_protection['reason']
2331                                         ];
2332                                 }
2333                         }
2334                 } elseif ( $action == 'move' ) {
2335                         // Check for immobile pages
2336                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2337                                 // Specific message for this case
2338                                 $errors[] = [ 'immobile-source-namespace', $this->getNsText() ];
2339                         } elseif ( !$this->isMovable() ) {
2340                                 // Less specific message for rarer cases
2341                                 $errors[] = [ 'immobile-source-page' ];
2342                         }
2343                 } elseif ( $action == 'move-target' ) {
2344                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2345                                 $errors[] = [ 'immobile-target-namespace', $this->getNsText() ];
2346                         } elseif ( !$this->isMovable() ) {
2347                                 $errors[] = [ 'immobile-target-page' ];
2348                         }
2349                 } elseif ( $action == 'delete' ) {
2350                         $tempErrors = $this->checkPageRestrictions( 'edit', $user, [], $rigor, true );
2351                         if ( !$tempErrors ) {
2352                                 $tempErrors = $this->checkCascadingSourcesRestrictions( 'edit',
2353                                         $user, $tempErrors, $rigor, true );
2354                         }
2355                         if ( $tempErrors ) {
2356                                 // If protection keeps them from editing, they shouldn't be able to delete.
2357                                 $errors[] = [ 'deleteprotected' ];
2358                         }
2359                         if ( $rigor !== 'quick' && $wgDeleteRevisionsLimit
2360                                 && !$this->userCan( 'bigdelete', $user ) && $this->isBigDeletion()
2361                         ) {
2362                                 $errors[] = [ 'delete-toobig', $wgLang->formatNum( $wgDeleteRevisionsLimit ) ];
2363                         }
2364                 } elseif ( $action === 'undelete' ) {
2365                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit', $user, $rigor, true ) ) ) {
2366                                 // Undeleting implies editing
2367                                 $errors[] = [ 'undelete-cantedit' ];
2368                         }
2369                         if ( !$this->exists()
2370                                 && count( $this->getUserPermissionsErrorsInternal( 'create', $user, $rigor, true ) )
2371                         ) {
2372                                 // Undeleting where nothing currently exists implies creating
2373                                 $errors[] = [ 'undelete-cantcreate' ];
2374                         }
2375                 }
2376                 return $errors;
2377         }
2378
2379         /**
2380          * Check that the user isn't blocked from editing.
2381          *
2382          * @param string $action The action to check
2383          * @param User $user User to check
2384          * @param array $errors List of current errors
2385          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2386          * @param bool $short Short circuit on first error
2387          *
2388          * @return array List of errors
2389          */
2390         private function checkUserBlock( $action, $user, $errors, $rigor, $short ) {
2391                 global $wgEmailConfirmToEdit, $wgBlockDisablesLogin;
2392                 // Account creation blocks handled at userlogin.
2393                 // Unblocking handled in SpecialUnblock
2394                 if ( $rigor === 'quick' || in_array( $action, [ 'createaccount', 'unblock' ] ) ) {
2395                         return $errors;
2396                 }
2397
2398                 // Optimize for a very common case
2399                 if ( $action === 'read' && !$wgBlockDisablesLogin ) {
2400                         return $errors;
2401                 }
2402
2403                 if ( $wgEmailConfirmToEdit && !$user->isEmailConfirmed() ) {
2404                         $errors[] = [ 'confirmedittext' ];
2405                 }
2406
2407                 $useSlave = ( $rigor !== 'secure' );
2408                 if ( ( $action == 'edit' || $action == 'create' )
2409                         && !$user->isBlockedFrom( $this, $useSlave )
2410                 ) {
2411                         // Don't block the user from editing their own talk page unless they've been
2412                         // explicitly blocked from that too.
2413                 } elseif ( $user->isBlocked() && $user->getBlock()->prevents( $action ) !== false ) {
2414                         // @todo FIXME: Pass the relevant context into this function.
2415                         $errors[] = $user->getBlock()->getPermissionsError( RequestContext::getMain() );
2416                 }
2417
2418                 return $errors;
2419         }
2420
2421         /**
2422          * Check that the user is allowed to read this page.
2423          *
2424          * @param string $action The action to check
2425          * @param User $user User to check
2426          * @param array $errors List of current errors
2427          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2428          * @param bool $short Short circuit on first error
2429          *
2430          * @return array List of errors
2431          */
2432         private function checkReadPermissions( $action, $user, $errors, $rigor, $short ) {
2433                 global $wgWhitelistRead, $wgWhitelistReadRegexp;
2434
2435                 $whitelisted = false;
2436                 if ( User::isEveryoneAllowed( 'read' ) ) {
2437                         # Shortcut for public wikis, allows skipping quite a bit of code
2438                         $whitelisted = true;
2439                 } elseif ( $user->isAllowed( 'read' ) ) {
2440                         # If the user is allowed to read pages, he is allowed to read all pages
2441                         $whitelisted = true;
2442                 } elseif ( $this->isSpecial( 'Userlogin' )
2443                         || $this->isSpecial( 'PasswordReset' )
2444                         || $this->isSpecial( 'Userlogout' )
2445                 ) {
2446                         # Always grant access to the login page.
2447                         # Even anons need to be able to log in.
2448                         $whitelisted = true;
2449                 } elseif ( is_array( $wgWhitelistRead ) && count( $wgWhitelistRead ) ) {
2450                         # Time to check the whitelist
2451                         # Only do these checks is there's something to check against
2452                         $name = $this->getPrefixedText();
2453                         $dbName = $this->getPrefixedDBkey();
2454
2455                         // Check for explicit whitelisting with and without underscores
2456                         if ( in_array( $name, $wgWhitelistRead, true ) || in_array( $dbName, $wgWhitelistRead, true ) ) {
2457                                 $whitelisted = true;
2458                         } elseif ( $this->getNamespace() == NS_MAIN ) {
2459                                 # Old settings might have the title prefixed with
2460                                 # a colon for main-namespace pages
2461                                 if ( in_array( ':' . $name, $wgWhitelistRead ) ) {
2462                                         $whitelisted = true;
2463                                 }
2464                         } elseif ( $this->isSpecialPage() ) {
2465                                 # If it's a special page, ditch the subpage bit and check again
2466                                 $name = $this->getDBkey();
2467                                 list( $name, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $name );
2468                                 if ( $name ) {
2469                                         $pure = SpecialPage::getTitleFor( $name )->getPrefixedText();
2470                                         if ( in_array( $pure, $wgWhitelistRead, true ) ) {
2471                                                 $whitelisted = true;
2472                                         }
2473                                 }
2474                         }
2475                 }
2476
2477                 if ( !$whitelisted && is_array( $wgWhitelistReadRegexp ) && !empty( $wgWhitelistReadRegexp ) ) {
2478                         $name = $this->getPrefixedText();
2479                         // Check for regex whitelisting
2480                         foreach ( $wgWhitelistReadRegexp as $listItem ) {
2481                                 if ( preg_match( $listItem, $name ) ) {
2482                                         $whitelisted = true;
2483                                         break;
2484                                 }
2485                         }
2486                 }
2487
2488                 if ( !$whitelisted ) {
2489                         # If the title is not whitelisted, give extensions a chance to do so...
2490                         Hooks::run( 'TitleReadWhitelist', [ $this, $user, &$whitelisted ] );
2491                         if ( !$whitelisted ) {
2492                                 $errors[] = $this->missingPermissionError( $action, $short );
2493                         }
2494                 }
2495
2496                 return $errors;
2497         }
2498
2499         /**
2500          * Get a description array when the user doesn't have the right to perform
2501          * $action (i.e. when User::isAllowed() returns false)
2502          *
2503          * @param string $action The action to check
2504          * @param bool $short Short circuit on first error
2505          * @return array Array containing an error message key and any parameters
2506          */
2507         private function missingPermissionError( $action, $short ) {
2508                 // We avoid expensive display logic for quickUserCan's and such
2509                 if ( $short ) {
2510                         return [ 'badaccess-group0' ];
2511                 }
2512
2513                 return User::newFatalPermissionDeniedStatus( $action )->getErrorsArray()[0];
2514         }
2515
2516         /**
2517          * Can $user perform $action on this page? This is an internal function,
2518          * with multiple levels of checks depending on performance needs; see $rigor below.
2519          * It does not check wfReadOnly().
2520          *
2521          * @param string $action Action that permission needs to be checked for
2522          * @param User $user User to check
2523          * @param string $rigor One of (quick,full,secure)
2524          *   - quick  : does cheap permission checks from replica DBs (usable for GUI creation)
2525          *   - full   : does cheap and expensive checks possibly from a replica DB
2526          *   - secure : does cheap and expensive checks, using the master as needed
2527          * @param bool $short Set this to true to stop after the first permission error.
2528          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
2529          */
2530         protected function getUserPermissionsErrorsInternal(
2531                 $action, $user, $rigor = 'secure', $short = false
2532         ) {
2533                 if ( $rigor === true ) {
2534                         $rigor = 'secure'; // b/c
2535                 } elseif ( $rigor === false ) {
2536                         $rigor = 'quick'; // b/c
2537                 } elseif ( !in_array( $rigor, [ 'quick', 'full', 'secure' ] ) ) {
2538                         throw new Exception( "Invalid rigor parameter '$rigor'." );
2539                 }
2540
2541                 # Read has special handling
2542                 if ( $action == 'read' ) {
2543                         $checks = [
2544                                 'checkPermissionHooks',
2545                                 'checkReadPermissions',
2546                                 'checkUserBlock', // for wgBlockDisablesLogin
2547                         ];
2548                 # Don't call checkSpecialsAndNSPermissions or checkCSSandJSPermissions
2549                 # here as it will lead to duplicate error messages. This is okay to do
2550                 # since anywhere that checks for create will also check for edit, and
2551                 # those checks are called for edit.
2552                 } elseif ( $action == 'create' ) {
2553                         $checks = [
2554                                 'checkQuickPermissions',
2555                                 'checkPermissionHooks',
2556                                 'checkPageRestrictions',
2557                                 'checkCascadingSourcesRestrictions',
2558                                 'checkActionPermissions',
2559                                 'checkUserBlock'
2560                         ];
2561                 } else {
2562                         $checks = [
2563                                 'checkQuickPermissions',
2564                                 'checkPermissionHooks',
2565                                 'checkSpecialsAndNSPermissions',
2566                                 'checkCSSandJSPermissions',
2567                                 'checkPageRestrictions',
2568                                 'checkCascadingSourcesRestrictions',
2569                                 'checkActionPermissions',
2570                                 'checkUserBlock'
2571                         ];
2572                 }
2573
2574                 $errors = [];
2575                 while ( count( $checks ) > 0 &&
2576                                 !( $short && count( $errors ) > 0 ) ) {
2577                         $method = array_shift( $checks );
2578                         $errors = $this->$method( $action, $user, $errors, $rigor, $short );
2579                 }
2580
2581                 return $errors;
2582         }
2583
2584         /**
2585          * Get a filtered list of all restriction types supported by this wiki.
2586          * @param bool $exists True to get all restriction types that apply to
2587          * titles that do exist, False for all restriction types that apply to
2588          * titles that do not exist
2589          * @return array
2590          */
2591         public static function getFilteredRestrictionTypes( $exists = true ) {
2592                 global $wgRestrictionTypes;
2593                 $types = $wgRestrictionTypes;
2594                 if ( $exists ) {
2595                         # Remove the create restriction for existing titles
2596                         $types = array_diff( $types, [ 'create' ] );
2597                 } else {
2598                         # Only the create and upload restrictions apply to non-existing titles
2599                         $types = array_intersect( $types, [ 'create', 'upload' ] );
2600                 }
2601                 return $types;
2602         }
2603
2604         /**
2605          * Returns restriction types for the current Title
2606          *
2607          * @return array Applicable restriction types
2608          */
2609         public function getRestrictionTypes() {
2610                 if ( $this->isSpecialPage() ) {
2611                         return [];
2612                 }
2613
2614                 $types = self::getFilteredRestrictionTypes( $this->exists() );
2615
2616                 if ( $this->getNamespace() != NS_FILE ) {
2617                         # Remove the upload restriction for non-file titles
2618                         $types = array_diff( $types, [ 'upload' ] );
2619                 }
2620
2621                 Hooks::run( 'TitleGetRestrictionTypes', [ $this, &$types ] );
2622
2623                 wfDebug( __METHOD__ . ': applicable restrictions to [[' .
2624                         $this->getPrefixedText() . ']] are {' . implode( ',', $types ) . "}\n" );
2625
2626                 return $types;
2627         }
2628
2629         /**
2630          * Is this title subject to title protection?
2631          * Title protection is the one applied against creation of such title.
2632          *
2633          * @return array|bool An associative array representing any existent title
2634          *   protection, or false if there's none.
2635          */
2636         public function getTitleProtection() {
2637                 $protection = $this->getTitleProtectionInternal();
2638                 if ( $protection ) {
2639                         if ( $protection['permission'] == 'sysop' ) {
2640                                 $protection['permission'] = 'editprotected'; // B/C
2641                         }
2642                         if ( $protection['permission'] == 'autoconfirmed' ) {
2643                                 $protection['permission'] = 'editsemiprotected'; // B/C
2644                         }
2645                 }
2646                 return $protection;
2647         }
2648
2649         /**
2650          * Fetch title protection settings
2651          *
2652          * To work correctly, $this->loadRestrictions() needs to have access to the
2653          * actual protections in the database without munging 'sysop' =>
2654          * 'editprotected' and 'autoconfirmed' => 'editsemiprotected'. Other
2655          * callers probably want $this->getTitleProtection() instead.
2656          *
2657          * @return array|bool
2658          */
2659         protected function getTitleProtectionInternal() {
2660                 // Can't protect pages in special namespaces
2661                 if ( $this->getNamespace() < 0 ) {
2662                         return false;
2663                 }
2664
2665                 // Can't protect pages that exist.
2666                 if ( $this->exists() ) {
2667                         return false;
2668                 }
2669
2670                 if ( $this->mTitleProtection === null ) {
2671                         $dbr = wfGetDB( DB_REPLICA );
2672                         $res = $dbr->select(
2673                                 'protected_titles',
2674                                 [
2675                                         'user' => 'pt_user',
2676                                         'reason' => 'pt_reason',
2677                                         'expiry' => 'pt_expiry',
2678                                         'permission' => 'pt_create_perm'
2679                                 ],
2680                                 [ 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ],
2681                                 __METHOD__
2682                         );
2683
2684                         // fetchRow returns false if there are no rows.
2685                         $row = $dbr->fetchRow( $res );
2686                         if ( $row ) {
2687                                 $row['expiry'] = $dbr->decodeExpiry( $row['expiry'] );
2688                         }
2689                         $this->mTitleProtection = $row;
2690                 }
2691                 return $this->mTitleProtection;
2692         }
2693
2694         /**
2695          * Remove any title protection due to page existing
2696          */
2697         public function deleteTitleProtection() {
2698                 $dbw = wfGetDB( DB_MASTER );
2699
2700                 $dbw->delete(
2701                         'protected_titles',
2702                         [ 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ],
2703                         __METHOD__
2704                 );
2705                 $this->mTitleProtection = false;
2706         }
2707
2708         /**
2709          * Is this page "semi-protected" - the *only* protection levels are listed
2710          * in $wgSemiprotectedRestrictionLevels?
2711          *
2712          * @param string $action Action to check (default: edit)
2713          * @return bool
2714          */
2715         public function isSemiProtected( $action = 'edit' ) {
2716                 global $wgSemiprotectedRestrictionLevels;
2717
2718                 $restrictions = $this->getRestrictions( $action );
2719                 $semi = $wgSemiprotectedRestrictionLevels;
2720                 if ( !$restrictions || !$semi ) {
2721                         // Not protected, or all protection is full protection
2722                         return false;
2723                 }
2724
2725                 // Remap autoconfirmed to editsemiprotected for BC
2726                 foreach ( array_keys( $semi, 'autoconfirmed' ) as $key ) {
2727                         $semi[$key] = 'editsemiprotected';
2728                 }
2729                 foreach ( array_keys( $restrictions, 'autoconfirmed' ) as $key ) {
2730                         $restrictions[$key] = 'editsemiprotected';
2731                 }
2732
2733                 return !array_diff( $restrictions, $semi );
2734         }
2735
2736         /**
2737          * Does the title correspond to a protected article?
2738          *
2739          * @param string $action The action the page is protected from,
2740          * by default checks all actions.
2741          * @return bool
2742          */
2743         public function isProtected( $action = '' ) {
2744                 global $wgRestrictionLevels;
2745
2746                 $restrictionTypes = $this->getRestrictionTypes();
2747
2748                 # Special pages have inherent protection
2749                 if ( $this->isSpecialPage() ) {
2750                         return true;
2751                 }
2752
2753                 # Check regular protection levels
2754                 foreach ( $restrictionTypes as $type ) {
2755                         if ( $action == $type || $action == '' ) {
2756                                 $r = $this->getRestrictions( $type );
2757                                 foreach ( $wgRestrictionLevels as $level ) {
2758                                         if ( in_array( $level, $r ) && $level != '' ) {
2759                                                 return true;
2760                                         }
2761                                 }
2762                         }
2763                 }
2764
2765                 return false;
2766         }
2767
2768         /**
2769          * Determines if $user is unable to edit this page because it has been protected
2770          * by $wgNamespaceProtection.
2771          *
2772          * @param User $user User object to check permissions
2773          * @return bool
2774          */
2775         public function isNamespaceProtected( User $user ) {
2776                 global $wgNamespaceProtection;
2777
2778                 if ( isset( $wgNamespaceProtection[$this->mNamespace] ) ) {
2779                         foreach ( (array)$wgNamespaceProtection[$this->mNamespace] as $right ) {
2780                                 if ( $right != '' && !$user->isAllowed( $right ) ) {
2781                                         return true;
2782                                 }
2783                         }
2784                 }
2785                 return false;
2786         }
2787
2788         /**
2789          * Cascading protection: Return true if cascading restrictions apply to this page, false if not.
2790          *
2791          * @return bool If the page is subject to cascading restrictions.
2792          */
2793         public function isCascadeProtected() {
2794                 list( $sources, /* $restrictions */ ) = $this->getCascadeProtectionSources( false );
2795                 return ( $sources > 0 );
2796         }
2797
2798         /**
2799          * Determines whether cascading protection sources have already been loaded from
2800          * the database.
2801          *
2802          * @param bool $getPages True to check if the pages are loaded, or false to check
2803          * if the status is loaded.
2804          * @return bool Whether or not the specified information has been loaded
2805          * @since 1.23
2806          */
2807         public function areCascadeProtectionSourcesLoaded( $getPages = true ) {
2808                 return $getPages ? $this->mCascadeSources !== null : $this->mHasCascadingRestrictions !== null;
2809         }
2810
2811         /**
2812          * Cascading protection: Get the source of any cascading restrictions on this page.
2813          *
2814          * @param bool $getPages Whether or not to retrieve the actual pages
2815          *        that the restrictions have come from and the actual restrictions
2816          *        themselves.
2817          * @return array Two elements: First is an array of Title objects of the
2818          *        pages from which cascading restrictions have come, false for
2819          *        none, or true if such restrictions exist but $getPages was not
2820          *        set. Second is an array like that returned by
2821          *        Title::getAllRestrictions(), or an empty array if $getPages is
2822          *        false.
2823          */
2824         public function getCascadeProtectionSources( $getPages = true ) {
2825                 $pagerestrictions = [];
2826
2827                 if ( $this->mCascadeSources !== null && $getPages ) {
2828                         return [ $this->mCascadeSources, $this->mCascadingRestrictions ];
2829                 } elseif ( $this->mHasCascadingRestrictions !== null && !$getPages ) {
2830                         return [ $this->mHasCascadingRestrictions, $pagerestrictions ];
2831                 }
2832
2833                 $dbr = wfGetDB( DB_REPLICA );
2834
2835                 if ( $this->getNamespace() == NS_FILE ) {
2836                         $tables = [ 'imagelinks', 'page_restrictions' ];
2837                         $where_clauses = [
2838                                 'il_to' => $this->getDBkey(),
2839                                 'il_from=pr_page',
2840                                 'pr_cascade' => 1
2841                         ];
2842                 } else {
2843                         $tables = [ 'templatelinks', 'page_restrictions' ];
2844                         $where_clauses = [
2845                                 'tl_namespace' => $this->getNamespace(),
2846                                 'tl_title' => $this->getDBkey(),
2847                                 'tl_from=pr_page',
2848                                 'pr_cascade' => 1
2849                         ];
2850                 }
2851
2852                 if ( $getPages ) {
2853                         $cols = [ 'pr_page', 'page_namespace', 'page_title',
2854                                 'pr_expiry', 'pr_type', 'pr_level' ];
2855                         $where_clauses[] = 'page_id=pr_page';
2856                         $tables[] = 'page';
2857                 } else {
2858                         $cols = [ 'pr_expiry' ];
2859                 }
2860
2861                 $res = $dbr->select( $tables, $cols, $where_clauses, __METHOD__ );
2862
2863                 $sources = $getPages ? [] : false;
2864                 $now = wfTimestampNow();
2865
2866                 foreach ( $res as $row ) {
2867                         $expiry = $dbr->decodeExpiry( $row->pr_expiry );
2868                         if ( $expiry > $now ) {
2869                                 if ( $getPages ) {
2870                                         $page_id = $row->pr_page;
2871                                         $page_ns = $row->page_namespace;
2872                                         $page_title = $row->page_title;
2873                                         $sources[$page_id] = self::makeTitle( $page_ns, $page_title );
2874                                         # Add groups needed for each restriction type if its not already there
2875                                         # Make sure this restriction type still exists
2876
2877                                         if ( !isset( $pagerestrictions[$row->pr_type] ) ) {
2878                                                 $pagerestrictions[$row->pr_type] = [];
2879                                         }
2880
2881                                         if (
2882                                                 isset( $pagerestrictions[$row->pr_type] )
2883                                                 && !in_array( $row->pr_level, $pagerestrictions[$row->pr_type] )
2884                                         ) {
2885                                                 $pagerestrictions[$row->pr_type][] = $row->pr_level;
2886                                         }
2887                                 } else {
2888                                         $sources = true;
2889                                 }
2890                         }
2891                 }
2892
2893                 if ( $getPages ) {
2894                         $this->mCascadeSources = $sources;
2895                         $this->mCascadingRestrictions = $pagerestrictions;
2896                 } else {
2897                         $this->mHasCascadingRestrictions = $sources;
2898                 }
2899
2900                 return [ $sources, $pagerestrictions ];
2901         }
2902
2903         /**
2904          * Accessor for mRestrictionsLoaded
2905          *
2906          * @return bool Whether or not the page's restrictions have already been
2907          * loaded from the database
2908          * @since 1.23
2909          */
2910         public function areRestrictionsLoaded() {
2911                 return $this->mRestrictionsLoaded;
2912         }
2913
2914         /**
2915          * Accessor/initialisation for mRestrictions
2916          *
2917          * @param string $action Action that permission needs to be checked for
2918          * @return array Restriction levels needed to take the action. All levels are
2919          *     required. Note that restriction levels are normally user rights, but 'sysop'
2920          *     and 'autoconfirmed' are also allowed for backwards compatibility. These should
2921          *     be mapped to 'editprotected' and 'editsemiprotected' respectively.
2922          */
2923         public function getRestrictions( $action ) {
2924                 if ( !$this->mRestrictionsLoaded ) {
2925                         $this->loadRestrictions();
2926                 }
2927                 return isset( $this->mRestrictions[$action] )
2928                                 ? $this->mRestrictions[$action]
2929                                 : [];
2930         }
2931
2932         /**
2933          * Accessor/initialisation for mRestrictions
2934          *
2935          * @return array Keys are actions, values are arrays as returned by
2936          *     Title::getRestrictions()
2937          * @since 1.23
2938          */
2939         public function getAllRestrictions() {
2940                 if ( !$this->mRestrictionsLoaded ) {
2941                         $this->loadRestrictions();
2942                 }
2943                 return $this->mRestrictions;
2944         }
2945
2946         /**
2947          * Get the expiry time for the restriction against a given action
2948          *
2949          * @param string $action
2950          * @return string|bool 14-char timestamp, or 'infinity' if the page is protected forever
2951          *     or not protected at all, or false if the action is not recognised.
2952          */
2953         public function getRestrictionExpiry( $action ) {
2954                 if ( !$this->mRestrictionsLoaded ) {
2955                         $this->loadRestrictions();
2956                 }
2957                 return isset( $this->mRestrictionsExpiry[$action] ) ? $this->mRestrictionsExpiry[$action] : false;
2958         }
2959
2960         /**
2961          * Returns cascading restrictions for the current article
2962          *
2963          * @return bool
2964          */
2965         function areRestrictionsCascading() {
2966                 if ( !$this->mRestrictionsLoaded ) {
2967                         $this->loadRestrictions();
2968                 }
2969
2970                 return $this->mCascadeRestriction;
2971         }
2972
2973         /**
2974          * Compiles list of active page restrictions from both page table (pre 1.10)
2975          * and page_restrictions table for this existing page.
2976          * Public for usage by LiquidThreads.
2977          *
2978          * @param array $rows Array of db result objects
2979          * @param string $oldFashionedRestrictions Comma-separated list of page
2980          *   restrictions from page table (pre 1.10)
2981          */
2982         public function loadRestrictionsFromRows( $rows, $oldFashionedRestrictions = null ) {
2983                 $dbr = wfGetDB( DB_REPLICA );
2984
2985                 $restrictionTypes = $this->getRestrictionTypes();
2986
2987                 foreach ( $restrictionTypes as $type ) {
2988                         $this->mRestrictions[$type] = [];
2989                         $this->mRestrictionsExpiry[$type] = 'infinity';
2990                 }
2991
2992                 $this->mCascadeRestriction = false;
2993
2994                 # Backwards-compatibility: also load the restrictions from the page record (old format).
2995                 if ( $oldFashionedRestrictions !== null ) {
2996                         $this->mOldRestrictions = $oldFashionedRestrictions;
2997                 }
2998
2999                 if ( $this->mOldRestrictions === false ) {
3000                         $this->mOldRestrictions = $dbr->selectField( 'page', 'page_restrictions',
3001                                 [ 'page_id' => $this->getArticleID() ], __METHOD__ );
3002                 }
3003
3004                 if ( $this->mOldRestrictions != '' ) {
3005                         foreach ( explode( ':', trim( $this->mOldRestrictions ) ) as $restrict ) {
3006                                 $temp = explode( '=', trim( $restrict ) );
3007                                 if ( count( $temp ) == 1 ) {
3008                                         // old old format should be treated as edit/move restriction
3009                                         $this->mRestrictions['edit'] = explode( ',', trim( $temp[0] ) );
3010                                         $this->mRestrictions['move'] = explode( ',', trim( $temp[0] ) );
3011                                 } else {
3012                                         $restriction = trim( $temp[1] );
3013                                         if ( $restriction != '' ) { // some old entries are empty
3014                                                 $this->mRestrictions[$temp[0]] = explode( ',', $restriction );
3015                                         }
3016                                 }
3017                         }
3018                 }
3019
3020                 if ( count( $rows ) ) {
3021                         # Current system - load second to make them override.
3022                         $now = wfTimestampNow();
3023
3024                         # Cycle through all the restrictions.
3025                         foreach ( $rows as $row ) {
3026                                 // Don't take care of restrictions types that aren't allowed
3027                                 if ( !in_array( $row->pr_type, $restrictionTypes ) ) {
3028                                         continue;
3029                                 }
3030
3031                                 $expiry = $dbr->decodeExpiry( $row->pr_expiry );
3032
3033                                 // Only apply the restrictions if they haven't expired!
3034                                 if ( !$expiry || $expiry > $now ) {
3035                                         $this->mRestrictionsExpiry[$row->pr_type] = $expiry;
3036                                         $this->mRestrictions[$row->pr_type] = explode( ',', trim( $row->pr_level ) );
3037
3038                                         $this->mCascadeRestriction |= $row->pr_cascade;
3039                                 }
3040                         }
3041                 }
3042
3043                 $this->mRestrictionsLoaded = true;
3044         }
3045
3046         /**
3047          * Load restrictions from the page_restrictions table
3048          *
3049          * @param string $oldFashionedRestrictions Comma-separated list of page
3050          *   restrictions from page table (pre 1.10)
3051          */
3052         public function loadRestrictions( $oldFashionedRestrictions = null ) {
3053                 if ( $this->mRestrictionsLoaded ) {
3054                         return;
3055                 }
3056
3057                 $id = $this->getArticleID();
3058                 if ( $id ) {
3059                         $cache = ObjectCache::getMainWANInstance();
3060                         $rows = $cache->getWithSetCallback(
3061                                 // Page protections always leave a new null revision
3062                                 $cache->makeKey( 'page-restrictions', $id, $this->getLatestRevID() ),
3063                                 $cache::TTL_DAY,
3064                                 function ( $curValue, &$ttl, array &$setOpts ) {
3065                                         $dbr = wfGetDB( DB_REPLICA );
3066
3067                                         $setOpts += Database::getCacheSetOptions( $dbr );
3068
3069                                         return iterator_to_array(
3070                                                 $dbr->select(
3071                                                         'page_restrictions',
3072                                                         [ 'pr_type', 'pr_expiry', 'pr_level', 'pr_cascade' ],
3073                                                         [ 'pr_page' => $this->getArticleID() ],
3074                                                         __METHOD__
3075                                                 )
3076                                         );
3077                                 }
3078                         );
3079
3080                         $this->loadRestrictionsFromRows( $rows, $oldFashionedRestrictions );
3081                 } else {
3082                         $title_protection = $this->getTitleProtectionInternal();
3083
3084                         if ( $title_protection ) {
3085                                 $now = wfTimestampNow();
3086                                 $expiry = wfGetDB( DB_REPLICA )->decodeExpiry( $title_protection['expiry'] );
3087
3088                                 if ( !$expiry || $expiry > $now ) {
3089                                         // Apply the restrictions
3090                                         $this->mRestrictionsExpiry['create'] = $expiry;
3091                                         $this->mRestrictions['create'] =
3092                                                 explode( ',', trim( $title_protection['permission'] ) );
3093                                 } else { // Get rid of the old restrictions
3094                                         $this->mTitleProtection = false;
3095                                 }
3096                         } else {
3097                                 $this->mRestrictionsExpiry['create'] = 'infinity';
3098                         }
3099                         $this->mRestrictionsLoaded = true;
3100                 }
3101         }
3102
3103         /**
3104          * Flush the protection cache in this object and force reload from the database.
3105          * This is used when updating protection from WikiPage::doUpdateRestrictions().
3106          */
3107         public function flushRestrictions() {
3108                 $this->mRestrictionsLoaded = false;
3109                 $this->mTitleProtection = null;
3110         }
3111
3112         /**
3113          * Purge expired restrictions from the page_restrictions table
3114          *
3115          * This will purge no more than $wgUpdateRowsPerQuery page_restrictions rows
3116          */
3117         static function purgeExpiredRestrictions() {
3118                 if ( wfReadOnly() ) {
3119                         return;
3120                 }
3121
3122                 DeferredUpdates::addUpdate( new AtomicSectionUpdate(
3123                         wfGetDB( DB_MASTER ),
3124                         __METHOD__,
3125                         function ( IDatabase $dbw, $fname ) {
3126                                 $config = MediaWikiServices::getInstance()->getMainConfig();
3127                                 $ids = $dbw->selectFieldValues(
3128                                         'page_restrictions',
3129                                         'pr_id',
3130                                         [ 'pr_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ],
3131                                         $fname,
3132                                         [ 'LIMIT' => $config->get( 'UpdateRowsPerQuery' ) ] // T135470
3133                                 );
3134                                 if ( $ids ) {
3135                                         $dbw->delete( 'page_restrictions', [ 'pr_id' => $ids ], $fname );
3136                                 }
3137                         }
3138                 ) );
3139
3140                 DeferredUpdates::addUpdate( new AtomicSectionUpdate(
3141                         wfGetDB( DB_MASTER ),
3142                         __METHOD__,
3143                         function ( IDatabase $dbw, $fname ) {
3144                                 $dbw->delete(
3145                                         'protected_titles',
3146                                         [ 'pt_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ],
3147                                         $fname
3148                                 );
3149                         }
3150                 ) );
3151         }
3152
3153         /**
3154          * Does this have subpages?  (Warning, usually requires an extra DB query.)
3155          *
3156          * @return bool
3157          */
3158         public function hasSubpages() {
3159                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
3160                         # Duh
3161                         return false;
3162                 }
3163
3164                 # We dynamically add a member variable for the purpose of this method
3165                 # alone to cache the result.  There's no point in having it hanging
3166                 # around uninitialized in every Title object; therefore we only add it
3167                 # if needed and don't declare it statically.
3168                 if ( $this->mHasSubpages === null ) {
3169                         $this->mHasSubpages = false;
3170                         $subpages = $this->getSubpages( 1 );
3171                         if ( $subpages instanceof TitleArray ) {
3172                                 $this->mHasSubpages = (bool)$subpages->count();
3173                         }
3174                 }
3175
3176                 return $this->mHasSubpages;
3177         }
3178
3179         /**
3180          * Get all subpages of this page.
3181          *
3182          * @param int $limit Maximum number of subpages to fetch; -1 for no limit
3183          * @return TitleArray|array TitleArray, or empty array if this page's namespace
3184          *  doesn't allow subpages
3185          */
3186         public function getSubpages( $limit = -1 ) {
3187                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3188                         return [];
3189                 }
3190
3191                 $dbr = wfGetDB( DB_REPLICA );
3192                 $conds['page_namespace'] = $this->getNamespace();
3193                 $conds[] = 'page_title ' . $dbr->buildLike( $this->getDBkey() . '/', $dbr->anyString() );
3194                 $options = [];
3195                 if ( $limit > -1 ) {
3196                         $options['LIMIT'] = $limit;
3197                 }
3198                 return TitleArray::newFromResult(
3199                         $dbr->select( 'page',
3200                                 [ 'page_id', 'page_namespace', 'page_title', 'page_is_redirect' ],
3201                                 $conds,
3202                                 __METHOD__,
3203                                 $options
3204                         )
3205                 );
3206         }
3207
3208         /**
3209          * Is there a version of this page in the deletion archive?
3210          *
3211          * @return int The number of archived revisions
3212          */
3213         public function isDeleted() {
3214                 if ( $this->getNamespace() < 0 ) {
3215                         $n = 0;
3216                 } else {
3217                         $dbr = wfGetDB( DB_REPLICA );
3218
3219                         $n = $dbr->selectField( 'archive', 'COUNT(*)',
3220                                 [ 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ],
3221                                 __METHOD__
3222                         );
3223                         if ( $this->getNamespace() == NS_FILE ) {
3224                                 $n += $dbr->selectField( 'filearchive', 'COUNT(*)',
3225                                         [ 'fa_name' => $this->getDBkey() ],
3226                                         __METHOD__
3227                                 );
3228                         }
3229                 }
3230                 return (int)$n;
3231         }
3232
3233         /**
3234          * Is there a version of this page in the deletion archive?
3235          *
3236          * @return bool
3237          */
3238         public function isDeletedQuick() {
3239                 if ( $this->getNamespace() < 0 ) {
3240                         return false;
3241                 }
3242                 $dbr = wfGetDB( DB_REPLICA );
3243                 $deleted = (bool)$dbr->selectField( 'archive', '1',
3244                         [ 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ],
3245                         __METHOD__
3246                 );
3247                 if ( !$deleted && $this->getNamespace() == NS_FILE ) {
3248                         $deleted = (bool)$dbr->selectField( 'filearchive', '1',
3249                                 [ 'fa_name' => $this->getDBkey() ],
3250                                 __METHOD__
3251                         );
3252                 }
3253                 return $deleted;
3254         }
3255
3256         /**
3257          * Get the article ID for this Title from the link cache,
3258          * adding it if necessary
3259          *
3260          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select
3261          *  for update
3262          * @return int The ID
3263          */
3264         public function getArticleID( $flags = 0 ) {
3265                 if ( $this->getNamespace() < 0 ) {
3266                         $this->mArticleID = 0;
3267                         return $this->mArticleID;
3268                 }
3269                 $linkCache = LinkCache::singleton();
3270                 if ( $flags & self::GAID_FOR_UPDATE ) {
3271                         $oldUpdate = $linkCache->forUpdate( true );
3272                         $linkCache->clearLink( $this );
3273                         $this->mArticleID = $linkCache->addLinkObj( $this );
3274                         $linkCache->forUpdate( $oldUpdate );
3275                 } else {
3276                         if ( -1 == $this->mArticleID ) {
3277                                 $this->mArticleID = $linkCache->addLinkObj( $this );
3278                         }
3279                 }
3280                 return $this->mArticleID;
3281         }
3282
3283         /**
3284          * Is this an article that is a redirect page?
3285          * Uses link cache, adding it if necessary
3286          *
3287          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3288          * @return bool
3289          */
3290         public function isRedirect( $flags = 0 ) {
3291                 if ( !is_null( $this->mRedirect ) ) {
3292                         return $this->mRedirect;
3293                 }
3294                 if ( !$this->getArticleID( $flags ) ) {
3295                         $this->mRedirect = false;
3296                         return $this->mRedirect;
3297                 }
3298
3299                 $linkCache = LinkCache::singleton();
3300                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3301                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'redirect' );
3302                 if ( $cached === null ) {
3303                         # Trust LinkCache's state over our own
3304                         # LinkCache is telling us that the page doesn't exist, despite there being cached
3305                         # data relating to an existing page in $this->mArticleID. Updaters should clear
3306                         # LinkCache as appropriate, or use $flags = Title::GAID_FOR_UPDATE. If that flag is
3307                         # set, then LinkCache will definitely be up to date here, since getArticleID() forces
3308                         # LinkCache to refresh its data from the master.
3309                         $this->mRedirect = false;
3310                         return $this->mRedirect;
3311                 }
3312
3313                 $this->mRedirect = (bool)$cached;
3314
3315                 return $this->mRedirect;
3316         }
3317
3318         /**
3319          * What is the length of this page?
3320          * Uses link cache, adding it if necessary
3321          *
3322          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3323          * @return int
3324          */
3325         public function getLength( $flags = 0 ) {
3326                 if ( $this->mLength != -1 ) {
3327                         return $this->mLength;
3328                 }
3329                 if ( !$this->getArticleID( $flags ) ) {
3330                         $this->mLength = 0;
3331                         return $this->mLength;
3332                 }
3333                 $linkCache = LinkCache::singleton();
3334                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3335                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'length' );
3336                 if ( $cached === null ) {
3337                         # Trust LinkCache's state over our own, as for isRedirect()
3338                         $this->mLength = 0;
3339                         return $this->mLength;
3340                 }
3341
3342                 $this->mLength = intval( $cached );
3343
3344                 return $this->mLength;
3345         }
3346
3347         /**
3348          * What is the page_latest field for this page?
3349          *
3350          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3351          * @return int Int or 0 if the page doesn't exist
3352          */
3353         public function getLatestRevID( $flags = 0 ) {
3354                 if ( !( $flags & self::GAID_FOR_UPDATE ) && $this->mLatestID !== false ) {
3355                         return intval( $this->mLatestID );
3356                 }
3357                 if ( !$this->getArticleID( $flags ) ) {
3358                         $this->mLatestID = 0;
3359                         return $this->mLatestID;
3360                 }
3361                 $linkCache = LinkCache::singleton();
3362                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3363                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'revision' );
3364                 if ( $cached === null ) {
3365                         # Trust LinkCache's state over our own, as for isRedirect()
3366                         $this->mLatestID = 0;
3367                         return $this->mLatestID;
3368                 }
3369
3370                 $this->mLatestID = intval( $cached );
3371
3372                 return $this->mLatestID;
3373         }
3374
3375         /**
3376          * This clears some fields in this object, and clears any associated
3377          * keys in the "bad links" section of the link cache.
3378          *
3379          * - This is called from WikiPage::doEditContent() and WikiPage::insertOn() to allow
3380          * loading of the new page_id. It's also called from
3381          * WikiPage::doDeleteArticleReal()
3382          *
3383          * @param int $newid The new Article ID
3384          */
3385         public function resetArticleID( $newid ) {
3386                 $linkCache = LinkCache::singleton();
3387                 $linkCache->clearLink( $this );
3388
3389                 if ( $newid === false ) {
3390                         $this->mArticleID = -1;
3391                 } else {
3392                         $this->mArticleID = intval( $newid );
3393                 }
3394                 $this->mRestrictionsLoaded = false;
3395                 $this->mRestrictions = [];
3396                 $this->mOldRestrictions = false;
3397                 $this->mRedirect = null;
3398                 $this->mLength = -1;
3399                 $this->mLatestID = false;
3400                 $this->mContentModel = false;
3401                 $this->mEstimateRevisions = null;
3402                 $this->mPageLanguage = false;
3403                 $this->mDbPageLanguage = false;
3404                 $this->mIsBigDeletion = null;
3405         }
3406
3407         public static function clearCaches() {
3408                 $linkCache = LinkCache::singleton();
3409                 $linkCache->clear();
3410
3411                 $titleCache = self::getTitleCache();
3412                 $titleCache->clear();
3413         }
3414
3415         /**
3416          * Capitalize a text string for a title if it belongs to a namespace that capitalizes
3417          *
3418          * @param string $text Containing title to capitalize
3419          * @param int $ns Namespace index, defaults to NS_MAIN
3420          * @return string Containing capitalized title
3421          */
3422         public static function capitalize( $text, $ns = NS_MAIN ) {
3423                 global $wgContLang;
3424
3425                 if ( MWNamespace::isCapitalized( $ns ) ) {
3426                         return $wgContLang->ucfirst( $text );
3427                 } else {
3428                         return $text;
3429                 }
3430         }
3431
3432         /**
3433          * Secure and split - main initialisation function for this object
3434          *
3435          * Assumes that mDbkeyform has been set, and is urldecoded
3436          * and uses underscores, but not otherwise munged.  This function
3437          * removes illegal characters, splits off the interwiki and
3438          * namespace prefixes, sets the other forms, and canonicalizes
3439          * everything.
3440          *
3441          * @throws MalformedTitleException On invalid titles
3442          * @return bool True on success
3443          */
3444         private function secureAndSplit() {
3445                 # Initialisation
3446                 $this->mInterwiki = '';
3447                 $this->mFragment = '';
3448                 $this->mNamespace = $this->mDefaultNamespace; # Usually NS_MAIN
3449
3450                 $dbkey = $this->mDbkeyform;
3451
3452                 // @note: splitTitleString() is a temporary hack to allow MediaWikiTitleCodec to share
3453                 //        the parsing code with Title, while avoiding massive refactoring.
3454                 // @todo: get rid of secureAndSplit, refactor parsing code.
3455                 // @note: getTitleParser() returns a TitleParser implementation which does not have a
3456                 //        splitTitleString method, but the only implementation (MediaWikiTitleCodec) does
3457                 $titleCodec = MediaWikiServices::getInstance()->getTitleParser();
3458                 // MalformedTitleException can be thrown here
3459                 $parts = $titleCodec->splitTitleString( $dbkey, $this->getDefaultNamespace() );
3460
3461                 # Fill fields
3462                 $this->setFragment( '#' . $parts['fragment'] );
3463                 $this->mInterwiki = $parts['interwiki'];
3464                 $this->mLocalInterwiki = $parts['local_interwiki'];
3465                 $this->mNamespace = $parts['namespace'];
3466                 $this->mUserCaseDBKey = $parts['user_case_dbkey'];
3467
3468                 $this->mDbkeyform = $parts['dbkey'];
3469                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
3470                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
3471
3472                 # We already know that some pages won't be in the database!
3473                 if ( $this->isExternal() || $this->isSpecialPage() ) {
3474                         $this->mArticleID = 0;
3475                 }
3476
3477                 return true;
3478         }
3479
3480         /**
3481          * Get an array of Title objects linking to this Title
3482          * Also stores the IDs in the link cache.
3483          *
3484          * WARNING: do not use this function on arbitrary user-supplied titles!
3485          * On heavily-used templates it will max out the memory.
3486          *
3487          * @param array $options May be FOR UPDATE
3488          * @param string $table Table name
3489          * @param string $prefix Fields prefix
3490          * @return Title[] Array of Title objects linking here
3491          */
3492         public function getLinksTo( $options = [], $table = 'pagelinks', $prefix = 'pl' ) {
3493                 if ( count( $options ) > 0 ) {
3494                         $db = wfGetDB( DB_MASTER );
3495                 } else {
3496                         $db = wfGetDB( DB_REPLICA );
3497                 }
3498
3499                 $res = $db->select(
3500                         [ 'page', $table ],
3501                         self::getSelectFields(),
3502                         [
3503                                 "{$prefix}_from=page_id",
3504                                 "{$prefix}_namespace" => $this->getNamespace(),
3505                                 "{$prefix}_title" => $this->getDBkey() ],
3506                         __METHOD__,
3507                         $options
3508                 );
3509
3510                 $retVal = [];
3511                 if ( $res->numRows() ) {
3512                         $linkCache = LinkCache::singleton();
3513                         foreach ( $res as $row ) {
3514                                 $titleObj = self::makeTitle( $row->page_namespace, $row->page_title );
3515                                 if ( $titleObj ) {
3516                                         $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3517                                         $retVal[] = $titleObj;
3518                                 }
3519                         }
3520                 }
3521                 return $retVal;
3522         }
3523
3524         /**
3525          * Get an array of Title objects using this Title as a template
3526          * Also stores the IDs in the link cache.
3527          *
3528          * WARNING: do not use this function on arbitrary user-supplied titles!
3529          * On heavily-used templates it will max out the memory.
3530          *
3531          * @param array $options Query option to Database::select()
3532          * @return Title[] Array of Title the Title objects linking here
3533          */
3534         public function getTemplateLinksTo( $options = [] ) {
3535                 return $this->getLinksTo( $options, 'templatelinks', 'tl' );
3536         }
3537
3538         /**
3539          * Get an array of Title objects linked from this Title
3540          * Also stores the IDs in the link cache.
3541          *
3542          * WARNING: do not use this function on arbitrary user-supplied titles!
3543          * On heavily-used templates it will max out the memory.
3544          *
3545          * @param array $options Query option to Database::select()
3546          * @param string $table Table name
3547          * @param string $prefix Fields prefix
3548          * @return array Array of Title objects linking here
3549          */
3550         public function getLinksFrom( $options = [], $table = 'pagelinks', $prefix = 'pl' ) {
3551                 $id = $this->getArticleID();
3552
3553                 # If the page doesn't exist; there can't be any link from this page
3554                 if ( !$id ) {
3555                         return [];
3556                 }
3557
3558                 $db = wfGetDB( DB_REPLICA );
3559
3560                 $blNamespace = "{$prefix}_namespace";
3561                 $blTitle = "{$prefix}_title";
3562
3563                 $res = $db->select(
3564                         [ $table, 'page' ],
3565                         array_merge(
3566                                 [ $blNamespace, $blTitle ],
3567                                 WikiPage::selectFields()
3568                         ),
3569                         [ "{$prefix}_from" => $id ],
3570                         __METHOD__,
3571                         $options,
3572                         [ 'page' => [
3573                                 'LEFT JOIN',
3574                                 [ "page_namespace=$blNamespace", "page_title=$blTitle" ]
3575                         ] ]
3576                 );
3577
3578                 $retVal = [];
3579                 $linkCache = LinkCache::singleton();
3580                 foreach ( $res as $row ) {
3581                         if ( $row->page_id ) {
3582                                 $titleObj = self::newFromRow( $row );
3583                         } else {
3584                                 $titleObj = self::makeTitle( $row->$blNamespace, $row->$blTitle );
3585                                 $linkCache->addBadLinkObj( $titleObj );
3586                         }
3587                         $retVal[] = $titleObj;
3588                 }
3589
3590                 return $retVal;
3591         }
3592
3593         /**
3594          * Get an array of Title objects used on this Title as a template
3595          * Also stores the IDs in the link cache.
3596          *
3597          * WARNING: do not use this function on arbitrary user-supplied titles!
3598          * On heavily-used templates it will max out the memory.
3599          *
3600          * @param array $options May be FOR UPDATE
3601          * @return Title[] Array of Title the Title objects used here
3602          */
3603         public function getTemplateLinksFrom( $options = [] ) {
3604                 return $this->getLinksFrom( $options, 'templatelinks', 'tl' );
3605         }
3606
3607         /**
3608          * Get an array of Title objects referring to non-existent articles linked
3609          * from this page.
3610          *
3611          * @todo check if needed (used only in SpecialBrokenRedirects.php, and
3612          *   should use redirect table in this case).
3613          * @return Title[] Array of Title the Title objects
3614          */
3615         public function getBrokenLinksFrom() {
3616                 if ( $this->getArticleID() == 0 ) {
3617                         # All links from article ID 0 are false positives
3618                         return [];
3619                 }
3620
3621                 $dbr = wfGetDB( DB_REPLICA );
3622                 $res = $dbr->select(
3623                         [ 'page', 'pagelinks' ],
3624                         [ 'pl_namespace', 'pl_title' ],
3625                         [
3626                                 'pl_from' => $this->getArticleID(),
3627                                 'page_namespace IS NULL'
3628                         ],
3629                         __METHOD__, [],
3630                         [
3631                                 'page' => [
3632                                         'LEFT JOIN',
3633                                         [ 'pl_namespace=page_namespace', 'pl_title=page_title' ]
3634                                 ]
3635                         ]
3636                 );
3637
3638                 $retVal = [];
3639                 foreach ( $res as $row ) {
3640                         $retVal[] = self::makeTitle( $row->pl_namespace, $row->pl_title );
3641                 }
3642                 return $retVal;
3643         }
3644
3645         /**
3646          * Get a list of URLs to purge from the CDN cache when this
3647          * page changes
3648          *
3649          * @return string[] Array of String the URLs
3650          */
3651         public function getCdnUrls() {
3652                 $urls = [
3653                         $this->getInternalURL(),
3654                         $this->getInternalURL( 'action=history' )
3655                 ];
3656
3657                 $pageLang = $this->getPageLanguage();
3658                 if ( $pageLang->hasVariants() ) {
3659                         $variants = $pageLang->getVariants();
3660                         foreach ( $variants as $vCode ) {
3661                                 $urls[] = $this->getInternalURL( $vCode );
3662                         }
3663                 }
3664
3665                 // If we are looking at a css/js user subpage, purge the action=raw.
3666                 if ( $this->isJsSubpage() ) {
3667                         $urls[] = $this->getInternalURL( 'action=raw&ctype=text/javascript' );
3668                 } elseif ( $this->isCssSubpage() ) {
3669                         $urls[] = $this->getInternalURL( 'action=raw&ctype=text/css' );
3670                 }
3671
3672                 Hooks::run( 'TitleSquidURLs', [ $this, &$urls ] );
3673                 return $urls;
3674         }
3675
3676         /**
3677          * @deprecated since 1.27 use getCdnUrls()
3678          */
3679         public function getSquidURLs() {
3680                 return $this->getCdnUrls();
3681         }
3682
3683         /**
3684          * Purge all applicable CDN URLs
3685          */
3686         public function purgeSquid() {
3687                 DeferredUpdates::addUpdate(
3688                         new CdnCacheUpdate( $this->getCdnUrls() ),
3689                         DeferredUpdates::PRESEND
3690                 );
3691         }
3692
3693         /**
3694          * Check whether a given move operation would be valid.
3695          * Returns true if ok, or a getUserPermissionsErrors()-like array otherwise
3696          *
3697          * @deprecated since 1.25, use MovePage's methods instead
3698          * @param Title &$nt The new title
3699          * @param bool $auth Whether to check user permissions (uses $wgUser)
3700          * @param string $reason Is the log summary of the move, used for spam checking
3701          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3702          */
3703         public function isValidMoveOperation( &$nt, $auth = true, $reason = '' ) {
3704                 global $wgUser;
3705
3706                 if ( !( $nt instanceof Title ) ) {
3707                         // Normally we'd add this to $errors, but we'll get
3708                         // lots of syntax errors if $nt is not an object
3709                         return [ [ 'badtitletext' ] ];
3710                 }
3711
3712                 $mp = new MovePage( $this, $nt );
3713                 $errors = $mp->isValidMove()->getErrorsArray();
3714                 if ( $auth ) {
3715                         $errors = wfMergeErrorArrays(
3716                                 $errors,
3717                                 $mp->checkPermissions( $wgUser, $reason )->getErrorsArray()
3718                         );
3719                 }
3720
3721                 return $errors ?: true;
3722         }
3723
3724         /**
3725          * Check if the requested move target is a valid file move target
3726          * @todo move this to MovePage
3727          * @param Title $nt Target title
3728          * @return array List of errors
3729          */
3730         protected function validateFileMoveOperation( $nt ) {
3731                 global $wgUser;
3732
3733                 $errors = [];
3734
3735                 $destFile = wfLocalFile( $nt );
3736                 $destFile->load( File::READ_LATEST );
3737                 if ( !$wgUser->isAllowed( 'reupload-shared' )
3738                         && !$destFile->exists() && wfFindFile( $nt )
3739                 ) {
3740                         $errors[] = [ 'file-exists-sharedrepo' ];
3741                 }
3742
3743                 return $errors;
3744         }
3745
3746         /**
3747          * Move a title to a new location
3748          *
3749          * @deprecated since 1.25, use the MovePage class instead
3750          * @param Title &$nt The new title
3751          * @param bool $auth Indicates whether $wgUser's permissions
3752          *  should be checked
3753          * @param string $reason The reason for the move
3754          * @param bool $createRedirect Whether to create a redirect from the old title to the new title.
3755          *  Ignored if the user doesn't have the suppressredirect right.
3756          * @param array $changeTags Applied to the entry in the move log and redirect page revision
3757          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3758          */
3759         public function moveTo( &$nt, $auth = true, $reason = '', $createRedirect = true,
3760                 array $changeTags = []
3761         ) {
3762                 global $wgUser;
3763                 $err = $this->isValidMoveOperation( $nt, $auth, $reason );
3764                 if ( is_array( $err ) ) {
3765                         // Auto-block user's IP if the account was "hard" blocked
3766                         $wgUser->spreadAnyEditBlock();
3767                         return $err;
3768                 }
3769                 // Check suppressredirect permission
3770                 if ( $auth && !$wgUser->isAllowed( 'suppressredirect' ) ) {
3771                         $createRedirect = true;
3772                 }
3773
3774                 $mp = new MovePage( $this, $nt );
3775                 $status = $mp->move( $wgUser, $reason, $createRedirect, $changeTags );
3776                 if ( $status->isOK() ) {
3777                         return true;
3778                 } else {
3779                         return $status->getErrorsArray();
3780                 }
3781         }
3782
3783         /**
3784          * Move this page's subpages to be subpages of $nt
3785          *
3786          * @param Title $nt Move target
3787          * @param bool $auth Whether $wgUser's permissions should be checked
3788          * @param string $reason The reason for the move
3789          * @param bool $createRedirect Whether to create redirects from the old subpages to
3790          *     the new ones Ignored if the user doesn't have the 'suppressredirect' right
3791          * @param array $changeTags Applied to the entry in the move log and redirect page revision
3792          * @return array Array with old page titles as keys, and strings (new page titles) or
3793          *     getUserPermissionsErrors()-like arrays (errors) as values, or a
3794          *     getUserPermissionsErrors()-like error array with numeric indices if
3795          *     no pages were moved
3796          */
3797         public function moveSubpages( $nt, $auth = true, $reason = '', $createRedirect = true,
3798                 array $changeTags = []
3799         ) {
3800                 global $wgMaximumMovedPages;
3801                 // Check permissions
3802                 if ( !$this->userCan( 'move-subpages' ) ) {
3803                         return [
3804                                 [ 'cant-move-subpages' ],
3805                         ];
3806                 }
3807                 // Do the source and target namespaces support subpages?
3808                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3809                         return [
3810                                 [ 'namespace-nosubpages', MWNamespace::getCanonicalName( $this->getNamespace() ) ],
3811                         ];
3812                 }
3813                 if ( !MWNamespace::hasSubpages( $nt->getNamespace() ) ) {
3814                         return [
3815                                 [ 'namespace-nosubpages', MWNamespace::getCanonicalName( $nt->getNamespace() ) ],
3816                         ];
3817                 }
3818
3819                 $subpages = $this->getSubpages( $wgMaximumMovedPages + 1 );
3820                 $retval = [];
3821                 $count = 0;
3822                 foreach ( $subpages as $oldSubpage ) {
3823                         $count++;
3824                         if ( $count > $wgMaximumMovedPages ) {
3825                                 $retval[$oldSubpage->getPrefixedText()] = [
3826                                         [ 'movepage-max-pages', $wgMaximumMovedPages ],
3827                                 ];
3828                                 break;
3829                         }
3830
3831                         // We don't know whether this function was called before
3832                         // or after moving the root page, so check both
3833                         // $this and $nt
3834                         if ( $oldSubpage->getArticleID() == $this->getArticleID()
3835                                 || $oldSubpage->getArticleID() == $nt->getArticleID()
3836                         ) {
3837                                 // When moving a page to a subpage of itself,
3838                                 // don't move it twice
3839                                 continue;
3840                         }
3841                         $newPageName = preg_replace(
3842                                         '#^' . preg_quote( $this->getDBkey(), '#' ) . '#',
3843                                         StringUtils::escapeRegexReplacement( $nt->getDBkey() ), # T23234
3844                                         $oldSubpage->getDBkey() );
3845                         if ( $oldSubpage->isTalkPage() ) {
3846                                 $newNs = $nt->getTalkPage()->getNamespace();
3847                         } else {
3848                                 $newNs = $nt->getSubjectPage()->getNamespace();
3849                         }
3850                         # T16385: we need makeTitleSafe because the new page names may
3851                         # be longer than 255 characters.
3852                         $newSubpage = self::makeTitleSafe( $newNs, $newPageName );
3853
3854                         $success = $oldSubpage->moveTo( $newSubpage, $auth, $reason, $createRedirect, $changeTags );
3855                         if ( $success === true ) {
3856                                 $retval[$oldSubpage->getPrefixedText()] = $newSubpage->getPrefixedText();
3857                         } else {
3858                                 $retval[$oldSubpage->getPrefixedText()] = $success;
3859                         }
3860                 }
3861                 return $retval;
3862         }
3863
3864         /**
3865          * Checks if this page is just a one-rev redirect.
3866          * Adds lock, so don't use just for light purposes.
3867          *
3868          * @return bool
3869          */
3870         public function isSingleRevRedirect() {
3871                 global $wgContentHandlerUseDB;
3872
3873                 $dbw = wfGetDB( DB_MASTER );
3874
3875                 # Is it a redirect?
3876                 $fields = [ 'page_is_redirect', 'page_latest', 'page_id' ];
3877                 if ( $wgContentHandlerUseDB ) {
3878                         $fields[] = 'page_content_model';
3879                 }
3880
3881                 $row = $dbw->selectRow( 'page',
3882                         $fields,
3883                         $this->pageCond(),
3884                         __METHOD__,
3885                         [ 'FOR UPDATE' ]
3886                 );
3887                 # Cache some fields we may want
3888                 $this->mArticleID = $row ? intval( $row->page_id ) : 0;
3889                 $this->mRedirect = $row ? (bool)$row->page_is_redirect : false;
3890                 $this->mLatestID = $row ? intval( $row->page_latest ) : false;
3891                 $this->mContentModel = $row && isset( $row->page_content_model )
3892                         ? strval( $row->page_content_model )
3893                         : false;
3894
3895                 if ( !$this->mRedirect ) {
3896                         return false;
3897                 }
3898                 # Does the article have a history?
3899                 $row = $dbw->selectField( [ 'page', 'revision' ],
3900                         'rev_id',
3901                         [ 'page_namespace' => $this->getNamespace(),
3902                                 'page_title' => $this->getDBkey(),
3903                                 'page_id=rev_page',
3904                                 'page_latest != rev_id'
3905                         ],
3906                         __METHOD__,
3907                         [ 'FOR UPDATE' ]
3908                 );
3909                 # Return true if there was no history
3910                 return ( $row === false );
3911         }
3912
3913         /**
3914          * Checks if $this can be moved to a given Title
3915          * - Selects for update, so don't call it unless you mean business
3916          *
3917          * @deprecated since 1.25, use MovePage's methods instead
3918          * @param Title $nt The new title to check
3919          * @return bool
3920          */
3921         public function isValidMoveTarget( $nt ) {
3922                 # Is it an existing file?
3923                 if ( $nt->getNamespace() == NS_FILE ) {
3924                         $file = wfLocalFile( $nt );
3925                         $file->load( File::READ_LATEST );
3926                         if ( $file->exists() ) {
3927                                 wfDebug( __METHOD__ . ": file exists\n" );
3928                                 return false;
3929                         }
3930                 }
3931                 # Is it a redirect with no history?
3932                 if ( !$nt->isSingleRevRedirect() ) {
3933                         wfDebug( __METHOD__ . ": not a one-rev redirect\n" );
3934                         return false;
3935                 }
3936                 # Get the article text
3937                 $rev = Revision::newFromTitle( $nt, false, Revision::READ_LATEST );
3938                 if ( !is_object( $rev ) ) {
3939                         return false;
3940                 }
3941                 $content = $rev->getContent();
3942                 # Does the redirect point to the source?
3943                 # Or is it a broken self-redirect, usually caused by namespace collisions?
3944                 $redirTitle = $content ? $content->getRedirectTarget() : null;
3945
3946                 if ( $redirTitle ) {
3947                         if ( $redirTitle->getPrefixedDBkey() != $this->getPrefixedDBkey() &&
3948                                 $redirTitle->getPrefixedDBkey() != $nt->getPrefixedDBkey() ) {
3949                                 wfDebug( __METHOD__ . ": redirect points to other page\n" );
3950                                 return false;
3951                         } else {
3952                                 return true;
3953                         }
3954                 } else {
3955                         # Fail safe (not a redirect after all. strange.)
3956                         wfDebug( __METHOD__ . ": failsafe: database sais " . $nt->getPrefixedDBkey() .
3957                                                 " is a redirect, but it doesn't contain a valid redirect.\n" );
3958                         return false;
3959                 }
3960         }
3961
3962         /**
3963          * Get categories to which this Title belongs and return an array of
3964          * categories' names.
3965          *
3966          * @return array Array of parents in the form:
3967          *     $parent => $currentarticle
3968          */
3969         public function getParentCategories() {
3970                 global $wgContLang;
3971
3972                 $data = [];
3973
3974                 $titleKey = $this->getArticleID();
3975
3976                 if ( $titleKey === 0 ) {
3977                         return $data;
3978                 }
3979
3980                 $dbr = wfGetDB( DB_REPLICA );
3981
3982                 $res = $dbr->select(
3983                         'categorylinks',
3984                         'cl_to',
3985                         [ 'cl_from' => $titleKey ],
3986                         __METHOD__
3987                 );
3988
3989                 if ( $res->numRows() > 0 ) {
3990                         foreach ( $res as $row ) {
3991                                 // $data[] = Title::newFromText($wgContLang->getNsText ( NS_CATEGORY ).':'.$row->cl_to);
3992                                 $data[$wgContLang->getNsText( NS_CATEGORY ) . ':' . $row->cl_to] = $this->getFullText();
3993                         }
3994                 }
3995                 return $data;
3996         }
3997
3998         /**
3999          * Get a tree of parent categories
4000          *
4001          * @param array $children Array with the children in the keys, to check for circular refs
4002          * @return array Tree of parent categories
4003          */
4004         public function getParentCategoryTree( $children = [] ) {
4005                 $stack = [];
4006                 $parents = $this->getParentCategories();
4007
4008                 if ( $parents ) {
4009                         foreach ( $parents as $parent => $current ) {
4010                                 if ( array_key_exists( $parent, $children ) ) {
4011                                         # Circular reference
4012                                         $stack[$parent] = [];
4013                                 } else {
4014                                         $nt = self::newFromText( $parent );
4015                                         if ( $nt ) {
4016                                                 $stack[$parent] = $nt->getParentCategoryTree( $children + [ $parent => 1 ] );
4017                                         }
4018                                 }
4019                         }
4020                 }
4021
4022                 return $stack;
4023         }
4024
4025         /**
4026          * Get an associative array for selecting this title from
4027          * the "page" table
4028          *
4029          * @return array Array suitable for the $where parameter of DB::select()
4030          */
4031         public function pageCond() {
4032                 if ( $this->mArticleID > 0 ) {
4033                         // PK avoids secondary lookups in InnoDB, shouldn't hurt other DBs
4034                         return [ 'page_id' => $this->mArticleID ];
4035                 } else {
4036                         return [ 'page_namespace' => $this->mNamespace, 'page_title' => $this->mDbkeyform ];
4037                 }
4038         }
4039
4040         /**
4041          * Get next/previous revision ID relative to another revision ID
4042          * @param int $revId Revision ID. Get the revision that was before this one.
4043          * @param int $flags Title::GAID_FOR_UPDATE
4044          * @param string $dir 'next' or 'prev'
4045          * @return int|bool New revision ID, or false if none exists
4046          */
4047         private function getRelativeRevisionID( $revId, $flags, $dir ) {
4048                 $revId = (int)$revId;
4049                 if ( $dir === 'next' ) {
4050                         $op = '>';
4051                         $sort = 'ASC';
4052                 } elseif ( $dir === 'prev' ) {
4053                         $op = '<';
4054                         $sort = 'DESC';
4055                 } else {
4056                         throw new InvalidArgumentException( '$dir must be "next" or "prev"' );
4057                 }
4058
4059                 if ( $flags & self::GAID_FOR_UPDATE ) {
4060                         $db = wfGetDB( DB_MASTER );
4061                 } else {
4062                         $db = wfGetDB( DB_REPLICA, 'contributions' );
4063                 }
4064
4065                 // Intentionally not caring if the specified revision belongs to this
4066                 // page. We only care about the timestamp.
4067                 $ts = $db->selectField( 'revision', 'rev_timestamp', [ 'rev_id' => $revId ], __METHOD__ );
4068                 if ( $ts === false ) {
4069                         $ts = $db->selectField( 'archive', 'ar_timestamp', [ 'ar_rev_id' => $revId ], __METHOD__ );
4070                         if ( $ts === false ) {
4071                                 // Or should this throw an InvalidArgumentException or something?
4072                                 return false;
4073                         }
4074                 }
4075                 $ts = $db->addQuotes( $ts );
4076
4077                 $revId = $db->selectField( 'revision', 'rev_id',
4078                         [
4079                                 'rev_page' => $this->getArticleID( $flags ),
4080                                 "rev_timestamp $op $ts OR (rev_timestamp = $ts AND rev_id $op $revId)"
4081                         ],
4082                         __METHOD__,
4083                         [
4084                                 'ORDER BY' => "rev_timestamp $sort, rev_id $sort",
4085                                 'IGNORE INDEX' => 'rev_timestamp', // Probably needed for T159319
4086                         ]
4087                 );
4088
4089                 if ( $revId === false ) {
4090                         return false;
4091                 } else {
4092                         return intval( $revId );
4093                 }
4094         }
4095
4096         /**
4097          * Get the revision ID of the previous revision
4098          *
4099          * @param int $revId Revision ID. Get the revision that was before this one.
4100          * @param int $flags Title::GAID_FOR_UPDATE
4101          * @return int|bool Old revision ID, or false if none exists
4102          */
4103         public function getPreviousRevisionID( $revId, $flags = 0 ) {
4104                 return $this->getRelativeRevisionID( $revId, $flags, 'prev' );
4105         }
4106
4107         /**
4108          * Get the revision ID of the next revision
4109          *
4110          * @param int $revId Revision ID. Get the revision that was after this one.
4111          * @param int $flags Title::GAID_FOR_UPDATE
4112          * @return int|bool Next revision ID, or false if none exists
4113          */
4114         public function getNextRevisionID( $revId, $flags = 0 ) {
4115                 return $this->getRelativeRevisionID( $revId, $flags, 'next' );
4116         }
4117
4118         /**
4119          * Get the first revision of the page
4120          *
4121          * @param int $flags Title::GAID_FOR_UPDATE
4122          * @return Revision|null If page doesn't exist
4123          */
4124         public function getFirstRevision( $flags = 0 ) {
4125                 $pageId = $this->getArticleID( $flags );
4126                 if ( $pageId ) {
4127                         $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_REPLICA );
4128                         $row = $db->selectRow( 'revision', Revision::selectFields(),
4129                                 [ 'rev_page' => $pageId ],
4130                                 __METHOD__,
4131                                 [
4132                                         'ORDER BY' => 'rev_timestamp ASC, rev_id ASC',
4133                                         'IGNORE INDEX' => 'rev_timestamp', // See T159319
4134                                 ]
4135                         );
4136                         if ( $row ) {
4137                                 return new Revision( $row );
4138                         }
4139                 }
4140                 return null;
4141         }
4142
4143         /**
4144          * Get the oldest revision timestamp of this page
4145          *
4146          * @param int $flags Title::GAID_FOR_UPDATE
4147          * @return string MW timestamp
4148          */
4149         public function getEarliestRevTime( $flags = 0 ) {
4150                 $rev = $this->getFirstRevision( $flags );
4151                 return $rev ? $rev->getTimestamp() : null;
4152         }
4153
4154         /**
4155          * Check if this is a new page
4156          *
4157          * @return bool
4158          */
4159         public function isNewPage() {
4160                 $dbr = wfGetDB( DB_REPLICA );
4161                 return (bool)$dbr->selectField( 'page', 'page_is_new', $this->pageCond(), __METHOD__ );
4162         }
4163
4164         /**
4165          * Check whether the number of revisions of this page surpasses $wgDeleteRevisionsLimit
4166          *
4167          * @return bool
4168          */
4169         public function isBigDeletion() {
4170                 global $wgDeleteRevisionsLimit;
4171
4172                 if ( !$wgDeleteRevisionsLimit ) {
4173                         return false;
4174                 }
4175
4176                 if ( $this->mIsBigDeletion === null ) {
4177                         $dbr = wfGetDB( DB_REPLICA );
4178
4179                         $revCount = $dbr->selectRowCount(
4180                                 'revision',
4181                                 '1',
4182                                 [ 'rev_page' => $this->getArticleID() ],
4183                                 __METHOD__,
4184                                 [ 'LIMIT' => $wgDeleteRevisionsLimit + 1 ]
4185                         );
4186
4187                         $this->mIsBigDeletion = $revCount > $wgDeleteRevisionsLimit;
4188                 }
4189
4190                 return $this->mIsBigDeletion;
4191         }
4192
4193         /**
4194          * Get the approximate revision count of this page.
4195          *
4196          * @return int
4197          */
4198         public function estimateRevisionCount() {
4199                 if ( !$this->exists() ) {
4200                         return 0;
4201                 }
4202
4203                 if ( $this->mEstimateRevisions === null ) {
4204                         $dbr = wfGetDB( DB_REPLICA );
4205                         $this->mEstimateRevisions = $dbr->estimateRowCount( 'revision', '*',
4206                                 [ 'rev_page' => $this->getArticleID() ], __METHOD__ );
4207                 }
4208
4209                 return $this->mEstimateRevisions;
4210         }
4211
4212         /**
4213          * Get the number of revisions between the given revision.
4214          * Used for diffs and other things that really need it.
4215          *
4216          * @param int|Revision $old Old revision or rev ID (first before range)
4217          * @param int|Revision $new New revision or rev ID (first after range)
4218          * @param int|null $max Limit of Revisions to count, will be incremented to detect truncations
4219          * @return int Number of revisions between these revisions.
4220          */
4221         public function countRevisionsBetween( $old, $new, $max = null ) {
4222                 if ( !( $old instanceof Revision ) ) {
4223                         $old = Revision::newFromTitle( $this, (int)$old );
4224                 }
4225                 if ( !( $new instanceof Revision ) ) {
4226                         $new = Revision::newFromTitle( $this, (int)$new );
4227                 }
4228                 if ( !$old || !$new ) {
4229                         return 0; // nothing to compare
4230                 }
4231                 $dbr = wfGetDB( DB_REPLICA );
4232                 $conds = [
4233                         'rev_page' => $this->getArticleID(),
4234                         'rev_timestamp > ' . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4235                         'rev_timestamp < ' . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4236                 ];
4237                 if ( $max !== null ) {
4238                         return $dbr->selectRowCount( 'revision', '1',
4239                                 $conds,
4240                                 __METHOD__,
4241                                 [ 'LIMIT' => $max + 1 ] // extra to detect truncation
4242                         );
4243                 } else {
4244                         return (int)$dbr->selectField( 'revision', 'count(*)', $conds, __METHOD__ );
4245                 }
4246         }
4247
4248         /**
4249          * Get the authors between the given revisions or revision IDs.
4250          * Used for diffs and other things that really need it.
4251          *
4252          * @since 1.23
4253          *
4254          * @param int|Revision $old Old revision or rev ID (first before range by default)
4255          * @param int|Revision $new New revision or rev ID (first after range by default)
4256          * @param int $limit Maximum number of authors
4257          * @param string|array $options (Optional): Single option, or an array of options:
4258          *     'include_old' Include $old in the range; $new is excluded.
4259          *     'include_new' Include $new in the range; $old is excluded.
4260          *     'include_both' Include both $old and $new in the range.
4261          *     Unknown option values are ignored.
4262          * @return array|null Names of revision authors in the range; null if not both revisions exist
4263          */
4264         public function getAuthorsBetween( $old, $new, $limit, $options = [] ) {
4265                 if ( !( $old instanceof Revision ) ) {
4266                         $old = Revision::newFromTitle( $this, (int)$old );
4267                 }
4268                 if ( !( $new instanceof Revision ) ) {
4269                         $new = Revision::newFromTitle( $this, (int)$new );
4270                 }
4271                 // XXX: what if Revision objects are passed in, but they don't refer to this title?
4272                 // Add $old->getPage() != $new->getPage() || $old->getPage() != $this->getArticleID()
4273                 // in the sanity check below?
4274                 if ( !$old || !$new ) {
4275                         return null; // nothing to compare
4276                 }
4277                 $authors = [];
4278                 $old_cmp = '>';
4279                 $new_cmp = '<';
4280                 $options = (array)$options;
4281                 if ( in_array( 'include_old', $options ) ) {
4282                         $old_cmp = '>=';
4283                 }
4284                 if ( in_array( 'include_new', $options ) ) {
4285                         $new_cmp = '<=';
4286                 }
4287                 if ( in_array( 'include_both', $options ) ) {
4288                         $old_cmp = '>=';
4289                         $new_cmp = '<=';
4290                 }
4291                 // No DB query needed if $old and $new are the same or successive revisions:
4292                 if ( $old->getId() === $new->getId() ) {
4293                         return ( $old_cmp === '>' && $new_cmp === '<' ) ?
4294                                 [] :
4295                                 [ $old->getUserText( Revision::RAW ) ];
4296                 } elseif ( $old->getId() === $new->getParentId() ) {
4297                         if ( $old_cmp === '>=' && $new_cmp === '<=' ) {
4298                                 $authors[] = $old->getUserText( Revision::RAW );
4299                                 if ( $old->getUserText( Revision::RAW ) != $new->getUserText( Revision::RAW ) ) {
4300                                         $authors[] = $new->getUserText( Revision::RAW );
4301                                 }
4302                         } elseif ( $old_cmp === '>=' ) {
4303                                 $authors[] = $old->getUserText( Revision::RAW );
4304                         } elseif ( $new_cmp === '<=' ) {
4305                                 $authors[] = $new->getUserText( Revision::RAW );
4306                         }
4307                         return $authors;
4308                 }
4309                 $dbr = wfGetDB( DB_REPLICA );
4310                 $res = $dbr->select( 'revision', 'DISTINCT rev_user_text',
4311                         [
4312                                 'rev_page' => $this->getArticleID(),
4313                                 "rev_timestamp $old_cmp " . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4314                                 "rev_timestamp $new_cmp " . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4315                         ], __METHOD__,
4316                         [ 'LIMIT' => $limit + 1 ] // add one so caller knows it was truncated
4317                 );
4318                 foreach ( $res as $row ) {
4319                         $authors[] = $row->rev_user_text;
4320                 }
4321                 return $authors;
4322         }
4323
4324         /**
4325          * Get the number of authors between the given revisions or revision IDs.
4326          * Used for diffs and other things that really need it.
4327          *
4328          * @param int|Revision $old Old revision or rev ID (first before range by default)
4329          * @param int|Revision $new New revision or rev ID (first after range by default)
4330          * @param int $limit Maximum number of authors
4331          * @param string|array $options (Optional): Single option, or an array of options:
4332          *     'include_old' Include $old in the range; $new is excluded.
4333          *     'include_new' Include $new in the range; $old is excluded.
4334          *     'include_both' Include both $old and $new in the range.
4335          *     Unknown option values are ignored.
4336          * @return int Number of revision authors in the range; zero if not both revisions exist
4337          */
4338         public function countAuthorsBetween( $old, $new, $limit, $options = [] ) {
4339                 $authors = $this->getAuthorsBetween( $old, $new, $limit, $options );
4340                 return $authors ? count( $authors ) : 0;
4341         }
4342
4343         /**
4344          * Compare with another title.
4345          *
4346          * @param Title $title
4347          * @return bool
4348          */
4349         public function equals( Title $title ) {
4350                 // Note: === is necessary for proper matching of number-like titles.
4351                 return $this->getInterwiki() === $title->getInterwiki()
4352                         && $this->getNamespace() == $title->getNamespace()
4353                         && $this->getDBkey() === $title->getDBkey();
4354         }
4355
4356         /**
4357          * Check if this title is a subpage of another title
4358          *
4359          * @param Title $title
4360          * @return bool
4361          */
4362         public function isSubpageOf( Title $title ) {
4363                 return $this->getInterwiki() === $title->getInterwiki()
4364                         && $this->getNamespace() == $title->getNamespace()
4365                         && strpos( $this->getDBkey(), $title->getDBkey() . '/' ) === 0;
4366         }
4367
4368         /**
4369          * Check if page exists.  For historical reasons, this function simply
4370          * checks for the existence of the title in the page table, and will
4371          * thus return false for interwiki links, special pages and the like.
4372          * If you want to know if a title can be meaningfully viewed, you should
4373          * probably call the isKnown() method instead.
4374          *
4375          * @param int $flags An optional bit field; may be Title::GAID_FOR_UPDATE to check
4376          *   from master/for update
4377          * @return bool
4378          */
4379         public function exists( $flags = 0 ) {
4380                 $exists = $this->getArticleID( $flags ) != 0;
4381                 Hooks::run( 'TitleExists', [ $this, &$exists ] );
4382                 return $exists;
4383         }
4384
4385         /**
4386          * Should links to this title be shown as potentially viewable (i.e. as
4387          * "bluelinks"), even if there's no record by this title in the page
4388          * table?
4389          *
4390          * This function is semi-deprecated for public use, as well as somewhat
4391          * misleadingly named.  You probably just want to call isKnown(), which
4392          * calls this function internally.
4393          *
4394          * (ISSUE: Most of these checks are cheap, but the file existence check
4395          * can potentially be quite expensive.  Including it here fixes a lot of
4396          * existing code, but we might want to add an optional parameter to skip
4397          * it and any other expensive checks.)
4398          *
4399          * @return bool
4400          */
4401         public function isAlwaysKnown() {
4402                 $isKnown = null;
4403
4404                 /**
4405                  * Allows overriding default behavior for determining if a page exists.
4406                  * If $isKnown is kept as null, regular checks happen. If it's
4407                  * a boolean, this value is returned by the isKnown method.
4408                  *
4409                  * @since 1.20
4410                  *
4411                  * @param Title $title
4412                  * @param bool|null $isKnown
4413                  */
4414                 Hooks::run( 'TitleIsAlwaysKnown', [ $this, &$isKnown ] );
4415
4416                 if ( !is_null( $isKnown ) ) {
4417                         return $isKnown;
4418                 }
4419
4420                 if ( $this->isExternal() ) {
4421                         return true;  // any interwiki link might be viewable, for all we know
4422                 }
4423
4424                 switch ( $this->mNamespace ) {
4425                         case NS_MEDIA:
4426                         case NS_FILE:
4427                                 // file exists, possibly in a foreign repo
4428                                 return (bool)wfFindFile( $this );
4429                         case NS_SPECIAL:
4430                                 // valid special page
4431                                 return SpecialPageFactory::exists( $this->getDBkey() );
4432                         case NS_MAIN:
4433                                 // selflink, possibly with fragment
4434                                 return $this->mDbkeyform == '';
4435                         case NS_MEDIAWIKI:
4436                                 // known system message
4437                                 return $this->hasSourceText() !== false;
4438                         default:
4439                                 return false;
4440                 }
4441         }
4442
4443         /**
4444          * Does this title refer to a page that can (or might) be meaningfully
4445          * viewed?  In particular, this function may be used to determine if
4446          * links to the title should be rendered as "bluelinks" (as opposed to
4447          * "redlinks" to non-existent pages).
4448          * Adding something else to this function will cause inconsistency
4449          * since LinkHolderArray calls isAlwaysKnown() and does its own
4450          * page existence check.
4451          *
4452          * @return bool
4453          */
4454         public function isKnown() {
4455                 return $this->isAlwaysKnown() || $this->exists();
4456         }
4457
4458         /**
4459          * Does this page have source text?
4460          *
4461          * @return bool
4462          */
4463         public function hasSourceText() {
4464                 if ( $this->exists() ) {
4465                         return true;
4466                 }
4467
4468                 if ( $this->mNamespace == NS_MEDIAWIKI ) {
4469                         // If the page doesn't exist but is a known system message, default
4470                         // message content will be displayed, same for language subpages-
4471                         // Use always content language to avoid loading hundreds of languages
4472                         // to get the link color.
4473                         global $wgContLang;
4474                         list( $name, ) = MessageCache::singleton()->figureMessage(
4475                                 $wgContLang->lcfirst( $this->getText() )
4476                         );
4477                         $message = wfMessage( $name )->inLanguage( $wgContLang )->useDatabase( false );
4478                         return $message->exists();
4479                 }
4480
4481                 return false;
4482         }
4483
4484         /**
4485          * Get the default message text or false if the message doesn't exist
4486          *
4487          * @return string|bool
4488          */
4489         public function getDefaultMessageText() {
4490                 global $wgContLang;
4491
4492                 if ( $this->getNamespace() != NS_MEDIAWIKI ) { // Just in case
4493                         return false;
4494                 }
4495
4496                 list( $name, $lang ) = MessageCache::singleton()->figureMessage(
4497                         $wgContLang->lcfirst( $this->getText() )
4498                 );
4499                 $message = wfMessage( $name )->inLanguage( $lang )->useDatabase( false );
4500
4501                 if ( $message->exists() ) {
4502                         return $message->plain();
4503                 } else {
4504                         return false;
4505                 }
4506         }
4507
4508         /**
4509          * Updates page_touched for this page; called from LinksUpdate.php
4510          *
4511          * @param string $purgeTime [optional] TS_MW timestamp
4512          * @return bool True if the update succeeded
4513          */
4514         public function invalidateCache( $purgeTime = null ) {
4515                 if ( wfReadOnly() ) {
4516                         return false;
4517                 } elseif ( $this->mArticleID === 0 ) {
4518                         return true; // avoid gap locking if we know it's not there
4519                 }
4520
4521                 $dbw = wfGetDB( DB_MASTER );
4522                 $dbw->onTransactionPreCommitOrIdle( function () {
4523                         ResourceLoaderWikiModule::invalidateModuleCache( $this, null, null, wfWikiID() );
4524                 } );
4525
4526                 $conds = $this->pageCond();
4527                 DeferredUpdates::addUpdate(
4528                         new AutoCommitUpdate(
4529                                 $dbw,
4530                                 __METHOD__,
4531                                 function ( IDatabase $dbw, $fname ) use ( $conds, $purgeTime ) {
4532                                         $dbTimestamp = $dbw->timestamp( $purgeTime ?: time() );
4533                                         $dbw->update(
4534                                                 'page',
4535                                                 [ 'page_touched' => $dbTimestamp ],
4536                                                 $conds + [ 'page_touched < ' . $dbw->addQuotes( $dbTimestamp ) ],
4537                                                 $fname
4538                                         );
4539                                         MediaWikiServices::getInstance()->getLinkCache()->invalidateTitle( $this );
4540                                 }
4541                         ),
4542                         DeferredUpdates::PRESEND
4543                 );
4544
4545                 return true;
4546         }
4547
4548         /**
4549          * Update page_touched timestamps and send CDN purge messages for
4550          * pages linking to this title. May be sent to the job queue depending
4551          * on the number of links. Typically called on create and delete.
4552          */
4553         public function touchLinks() {
4554                 DeferredUpdates::addUpdate( new HTMLCacheUpdate( $this, 'pagelinks' ) );
4555                 if ( $this->getNamespace() == NS_CATEGORY ) {
4556                         DeferredUpdates::addUpdate( new HTMLCacheUpdate( $this, 'categorylinks' ) );
4557                 }
4558         }
4559
4560         /**
4561          * Get the last touched timestamp
4562          *
4563          * @param IDatabase $db Optional db
4564          * @return string|false Last-touched timestamp
4565          */
4566         public function getTouched( $db = null ) {
4567                 if ( $db === null ) {
4568                         $db = wfGetDB( DB_REPLICA );
4569                 }
4570                 $touched = $db->selectField( 'page', 'page_touched', $this->pageCond(), __METHOD__ );
4571                 return $touched;
4572         }
4573
4574         /**
4575          * Get the timestamp when this page was updated since the user last saw it.
4576          *
4577          * @param User $user
4578          * @return string|null
4579          */
4580         public function getNotificationTimestamp( $user = null ) {
4581                 global $wgUser;
4582
4583                 // Assume current user if none given
4584                 if ( !$user ) {
4585                         $user = $wgUser;
4586                 }
4587                 // Check cache first
4588                 $uid = $user->getId();
4589                 if ( !$uid ) {
4590                         return false;
4591                 }
4592                 // avoid isset here, as it'll return false for null entries
4593                 if ( array_key_exists( $uid, $this->mNotificationTimestamp ) ) {
4594                         return $this->mNotificationTimestamp[$uid];
4595                 }
4596                 // Don't cache too much!
4597                 if ( count( $this->mNotificationTimestamp ) >= self::CACHE_MAX ) {
4598                         $this->mNotificationTimestamp = [];
4599                 }
4600
4601                 $store = MediaWikiServices::getInstance()->getWatchedItemStore();
4602                 $watchedItem = $store->getWatchedItem( $user, $this );
4603                 if ( $watchedItem ) {
4604                         $this->mNotificationTimestamp[$uid] = $watchedItem->getNotificationTimestamp();
4605                 } else {
4606                         $this->mNotificationTimestamp[$uid] = false;
4607                 }
4608
4609                 return $this->mNotificationTimestamp[$uid];
4610         }
4611
4612         /**
4613          * Generate strings used for xml 'id' names in monobook tabs
4614          *
4615          * @param string $prepend Defaults to 'nstab-'
4616          * @return string XML 'id' name
4617          */
4618         public function getNamespaceKey( $prepend = 'nstab-' ) {
4619                 global $wgContLang;
4620                 // Gets the subject namespace if this title
4621                 $namespace = MWNamespace::getSubject( $this->getNamespace() );
4622                 // Checks if canonical namespace name exists for namespace
4623                 if ( MWNamespace::exists( $this->getNamespace() ) ) {
4624                         // Uses canonical namespace name
4625                         $namespaceKey = MWNamespace::getCanonicalName( $namespace );
4626                 } else {
4627                         // Uses text of namespace
4628                         $namespaceKey = $this->getSubjectNsText();
4629                 }
4630                 // Makes namespace key lowercase
4631                 $namespaceKey = $wgContLang->lc( $namespaceKey );
4632                 // Uses main
4633                 if ( $namespaceKey == '' ) {
4634                         $namespaceKey = 'main';
4635                 }
4636                 // Changes file to image for backwards compatibility
4637                 if ( $namespaceKey == 'file' ) {
4638                         $namespaceKey = 'image';
4639                 }
4640                 return $prepend . $namespaceKey;
4641         }
4642
4643         /**
4644          * Get all extant redirects to this Title
4645          *
4646          * @param int|null $ns Single namespace to consider; null to consider all namespaces
4647          * @return Title[] Array of Title redirects to this title
4648          */
4649         public function getRedirectsHere( $ns = null ) {
4650                 $redirs = [];
4651
4652                 $dbr = wfGetDB( DB_REPLICA );
4653                 $where = [
4654                         'rd_namespace' => $this->getNamespace(),
4655                         'rd_title' => $this->getDBkey(),
4656                         'rd_from = page_id'
4657                 ];
4658                 if ( $this->isExternal() ) {
4659                         $where['rd_interwiki'] = $this->getInterwiki();
4660                 } else {
4661                         $where[] = 'rd_interwiki = ' . $dbr->addQuotes( '' ) . ' OR rd_interwiki IS NULL';
4662                 }
4663                 if ( !is_null( $ns ) ) {
4664                         $where['page_namespace'] = $ns;
4665                 }
4666
4667                 $res = $dbr->select(
4668                         [ 'redirect', 'page' ],
4669                         [ 'page_namespace', 'page_title' ],
4670                         $where,
4671                         __METHOD__
4672                 );
4673
4674                 foreach ( $res as $row ) {
4675                         $redirs[] = self::newFromRow( $row );
4676                 }
4677                 return $redirs;
4678         }
4679
4680         /**
4681          * Check if this Title is a valid redirect target
4682          *
4683          * @return bool
4684          */
4685         public function isValidRedirectTarget() {
4686                 global $wgInvalidRedirectTargets;
4687
4688                 if ( $this->isSpecialPage() ) {
4689                         // invalid redirect targets are stored in a global array, but explicitly disallow Userlogout here
4690                         if ( $this->isSpecial( 'Userlogout' ) ) {
4691                                 return false;
4692                         }
4693
4694                         foreach ( $wgInvalidRedirectTargets as $target ) {
4695                                 if ( $this->isSpecial( $target ) ) {
4696                                         return false;
4697                                 }
4698                         }
4699                 }
4700
4701                 return true;
4702         }
4703
4704         /**
4705          * Get a backlink cache object
4706          *
4707          * @return BacklinkCache
4708          */
4709         public function getBacklinkCache() {
4710                 return BacklinkCache::get( $this );
4711         }
4712
4713         /**
4714          * Whether the magic words __INDEX__ and __NOINDEX__ function for this page.
4715          *
4716          * @return bool
4717          */
4718         public function canUseNoindex() {
4719                 global $wgExemptFromUserRobotsControl;
4720
4721                 $bannedNamespaces = is_null( $wgExemptFromUserRobotsControl )
4722                         ? MWNamespace::getContentNamespaces()
4723                         : $wgExemptFromUserRobotsControl;
4724
4725                 return !in_array( $this->mNamespace, $bannedNamespaces );
4726         }
4727
4728         /**
4729          * Returns the raw sort key to be used for categories, with the specified
4730          * prefix.  This will be fed to Collation::getSortKey() to get a
4731          * binary sortkey that can be used for actual sorting.
4732          *
4733          * @param string $prefix The prefix to be used, specified using
4734          *   {{defaultsort:}} or like [[Category:Foo|prefix]].  Empty for no
4735          *   prefix.
4736          * @return string
4737          */
4738         public function getCategorySortkey( $prefix = '' ) {
4739                 $unprefixed = $this->getText();
4740
4741                 // Anything that uses this hook should only depend
4742                 // on the Title object passed in, and should probably
4743                 // tell the users to run updateCollations.php --force
4744                 // in order to re-sort existing category relations.
4745                 Hooks::run( 'GetDefaultSortkey', [ $this, &$unprefixed ] );
4746                 if ( $prefix !== '' ) {
4747                         # Separate with a line feed, so the unprefixed part is only used as
4748                         # a tiebreaker when two pages have the exact same prefix.
4749                         # In UCA, tab is the only character that can sort above LF
4750                         # so we strip both of them from the original prefix.
4751                         $prefix = strtr( $prefix, "\n\t", '  ' );
4752                         return "$prefix\n$unprefixed";
4753                 }
4754                 return $unprefixed;
4755         }
4756
4757         /**
4758          * Returns the page language code saved in the database, if $wgPageLanguageUseDB is set
4759          * to true in LocalSettings.php, otherwise returns false. If there is no language saved in
4760          * the db, it will return NULL.
4761          *
4762          * @return string|null|bool
4763          */
4764         private function getDbPageLanguageCode() {
4765                 global $wgPageLanguageUseDB;
4766
4767                 // check, if the page language could be saved in the database, and if so and
4768                 // the value is not requested already, lookup the page language using LinkCache
4769                 if ( $wgPageLanguageUseDB && $this->mDbPageLanguage === false ) {
4770                         $linkCache = LinkCache::singleton();
4771                         $linkCache->addLinkObj( $this );
4772                         $this->mDbPageLanguage = $linkCache->getGoodLinkFieldObj( $this, 'lang' );
4773                 }
4774
4775                 return $this->mDbPageLanguage;
4776         }
4777
4778         /**
4779          * Get the language in which the content of this page is written in
4780          * wikitext. Defaults to $wgContLang, but in certain cases it can be
4781          * e.g. $wgLang (such as special pages, which are in the user language).
4782          *
4783          * @since 1.18
4784          * @return Language
4785          */
4786         public function getPageLanguage() {
4787                 global $wgLang, $wgLanguageCode;
4788                 if ( $this->isSpecialPage() ) {
4789                         // special pages are in the user language
4790                         return $wgLang;
4791                 }
4792
4793                 // Checking if DB language is set
4794                 $dbPageLanguage = $this->getDbPageLanguageCode();
4795                 if ( $dbPageLanguage ) {
4796                         return wfGetLangObj( $dbPageLanguage );
4797                 }
4798
4799                 if ( !$this->mPageLanguage || $this->mPageLanguage[1] !== $wgLanguageCode ) {
4800                         // Note that this may depend on user settings, so the cache should
4801                         // be only per-request.
4802                         // NOTE: ContentHandler::getPageLanguage() may need to load the
4803                         // content to determine the page language!
4804                         // Checking $wgLanguageCode hasn't changed for the benefit of unit
4805                         // tests.
4806                         $contentHandler = ContentHandler::getForTitle( $this );
4807                         $langObj = $contentHandler->getPageLanguage( $this );
4808                         $this->mPageLanguage = [ $langObj->getCode(), $wgLanguageCode ];
4809                 } else {
4810                         $langObj = wfGetLangObj( $this->mPageLanguage[0] );
4811                 }
4812
4813                 return $langObj;
4814         }
4815
4816         /**
4817          * Get the language in which the content of this page is written when
4818          * viewed by user. Defaults to $wgContLang, but in certain cases it can be
4819          * e.g. $wgLang (such as special pages, which are in the user language).
4820          *
4821          * @since 1.20
4822          * @return Language
4823          */
4824         public function getPageViewLanguage() {
4825                 global $wgLang;
4826
4827                 if ( $this->isSpecialPage() ) {
4828                         // If the user chooses a variant, the content is actually
4829                         // in a language whose code is the variant code.
4830                         $variant = $wgLang->getPreferredVariant();
4831                         if ( $wgLang->getCode() !== $variant ) {
4832                                 return Language::factory( $variant );
4833                         }
4834
4835                         return $wgLang;
4836                 }
4837
4838                 // Checking if DB language is set
4839                 $dbPageLanguage = $this->getDbPageLanguageCode();
4840                 if ( $dbPageLanguage ) {
4841                         $pageLang = wfGetLangObj( $dbPageLanguage );
4842                         $variant = $pageLang->getPreferredVariant();
4843                         if ( $pageLang->getCode() !== $variant ) {
4844                                 $pageLang = Language::factory( $variant );
4845                         }
4846
4847                         return $pageLang;
4848                 }
4849
4850                 // @note Can't be cached persistently, depends on user settings.
4851                 // @note ContentHandler::getPageViewLanguage() may need to load the
4852                 //   content to determine the page language!
4853                 $contentHandler = ContentHandler::getForTitle( $this );
4854                 $pageLang = $contentHandler->getPageViewLanguage( $this );
4855                 return $pageLang;
4856         }
4857
4858         /**
4859          * Get a list of rendered edit notices for this page.
4860          *
4861          * Array is keyed by the original message key, and values are rendered using parseAsBlock, so
4862          * they will already be wrapped in paragraphs.
4863          *
4864          * @since 1.21
4865          * @param int $oldid Revision ID that's being edited
4866          * @return array
4867          */
4868         public function getEditNotices( $oldid = 0 ) {
4869                 $notices = [];
4870
4871                 // Optional notice for the entire namespace
4872                 $editnotice_ns = 'editnotice-' . $this->getNamespace();
4873                 $msg = wfMessage( $editnotice_ns );
4874                 if ( $msg->exists() ) {
4875                         $html = $msg->parseAsBlock();
4876                         // Edit notices may have complex logic, but output nothing (T91715)
4877                         if ( trim( $html ) !== '' ) {
4878                                 $notices[$editnotice_ns] = Html::rawElement(
4879                                         'div',
4880                                         [ 'class' => [
4881                                                 'mw-editnotice',
4882                                                 'mw-editnotice-namespace',
4883                                                 Sanitizer::escapeClass( "mw-$editnotice_ns" )
4884                                         ] ],
4885                                         $html
4886                                 );
4887                         }
4888                 }
4889
4890                 if ( MWNamespace::hasSubpages( $this->getNamespace() ) ) {
4891                         // Optional notice for page itself and any parent page
4892                         $parts = explode( '/', $this->getDBkey() );
4893                         $editnotice_base = $editnotice_ns;
4894                         while ( count( $parts ) > 0 ) {
4895                                 $editnotice_base .= '-' . array_shift( $parts );
4896                                 $msg = wfMessage( $editnotice_base );
4897                                 if ( $msg->exists() ) {
4898                                         $html = $msg->parseAsBlock();
4899                                         if ( trim( $html ) !== '' ) {
4900                                                 $notices[$editnotice_base] = Html::rawElement(
4901                                                         'div',
4902                                                         [ 'class' => [
4903                                                                 'mw-editnotice',
4904                                                                 'mw-editnotice-base',
4905                                                                 Sanitizer::escapeClass( "mw-$editnotice_base" )
4906                                                         ] ],
4907                                                         $html
4908                                                 );
4909                                         }
4910                                 }
4911                         }
4912                 } else {
4913                         // Even if there are no subpages in namespace, we still don't want "/" in MediaWiki message keys
4914                         $editnoticeText = $editnotice_ns . '-' . strtr( $this->getDBkey(), '/', '-' );
4915                         $msg = wfMessage( $editnoticeText );
4916                         if ( $msg->exists() ) {
4917                                 $html = $msg->parseAsBlock();
4918                                 if ( trim( $html ) !== '' ) {
4919                                         $notices[$editnoticeText] = Html::rawElement(
4920                                                 'div',
4921                                                 [ 'class' => [
4922                                                         'mw-editnotice',
4923                                                         'mw-editnotice-page',
4924                                                         Sanitizer::escapeClass( "mw-$editnoticeText" )
4925                                                 ] ],
4926                                                 $html
4927                                         );
4928                                 }
4929                         }
4930                 }
4931
4932                 Hooks::run( 'TitleGetEditNotices', [ $this, $oldid, &$notices ] );
4933                 return $notices;
4934         }
4935
4936         /**
4937          * @return array
4938          */
4939         public function __sleep() {
4940                 return [
4941                         'mNamespace',
4942                         'mDbkeyform',
4943                         'mFragment',
4944                         'mInterwiki',
4945                         'mLocalInterwiki',
4946                         'mUserCaseDBKey',
4947                         'mDefaultNamespace',
4948                 ];
4949         }
4950
4951         public function __wakeup() {
4952                 $this->mArticleID = ( $this->mNamespace >= 0 ) ? -1 : 0;
4953                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
4954                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
4955         }
4956
4957 }