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 use MediaWiki\Linker\LinkTarget;
  25
  26 use MediaWiki\MediaWikiServices;
  27
  28 /**
  29  * Represents a title within MediaWiki.
  30  * Optionally may contain an interwiki designation or namespace.
  31  * @note This class can fetch various kinds of data from the database;
  32  *       however, it does so inefficiently.
  33  * @note Consider using a TitleValue object instead. TitleValue is more lightweight
  34  *       and does not rely on global state or the database.
  35  */
  36 class Title implements LinkTarget {
  37         /** @var HashBagOStuff */
  38         static private $titleCache = null;
  39
  40         /**
  41          * Title::newFromText maintains a cache to avoid expensive re-normalization of
  42          * commonly used titles. On a batch operation this can become a memory leak
  43          * if not bounded. After hitting this many titles reset the cache.
  44          */
  45         const CACHE_MAX = 1000;
  46
  47         /**
  48          * Used to be GAID_FOR_UPDATE define. Used with getArticleID() and friends
  49          * to use the master DB
  50          */
  51         const GAID_FOR_UPDATE = 1;
  52
  53         /**
  54          * @name Private member variables
  55          * Please use the accessor functions instead.
  56          * @private
  57          */
  58         // @{
  59
  60         /** @var string Text form (spaces not underscores) of the main part */
  61         public $mTextform = '';
  62
  63         /** @var string URL-encoded form of the main part */
  64         public $mUrlform = '';
  65
  66         /** @var string Main part with underscores */
  67         public $mDbkeyform = '';
  68
  69         /** @var string Database key with the initial letter in the case specified by the user */
  70         protected $mUserCaseDBKey;
  71
  72         /** @var int Namespace index, i.e. one of the NS_xxxx constants */
  73         public $mNamespace = NS_MAIN;
  74
  75         /** @var string Interwiki prefix */
  76         public $mInterwiki = '';
  77
  78         /** @var bool Was this Title created from a string with a local interwiki prefix? */
  79         private $mLocalInterwiki = false;
  80
  81         /** @var string Title fragment (i.e. the bit after the #) */
  82         public $mFragment = '';
  83
  84         /** @var int Article ID, fetched from the link cache on demand */
  85         public $mArticleID = -1;
  86
  87         /** @var bool|int ID of most recent revision */
  88         protected $mLatestID = false;
  89
  90         /**
  91          * @var bool|string ID of the page's content model, i.e. one of the
  92          *   CONTENT_MODEL_XXX constants
  93          */
  94         public $mContentModel = false;
  95
  96         /** @var int Estimated number of revisions; null of not loaded */
  97         private $mEstimateRevisions;
  98
  99         /** @var array Array of groups allowed to edit this article */
 100         public $mRestrictions = [];
 101
 102         /** @var string|bool */
 103         protected $mOldRestrictions = false;
 104
 105         /** @var bool Cascade restrictions on this page to included templates and images? */
 106         public $mCascadeRestriction;
 107
 108         /** Caching the results of getCascadeProtectionSources */
 109         public $mCascadingRestrictions;
 110
 111         /** @var array When do the restrictions on this page expire? */
 112         protected $mRestrictionsExpiry = [];
 113
 114         /** @var bool Are cascading restrictions in effect on this page? */
 115         protected $mHasCascadingRestrictions;
 116
 117         /** @var array Where are the cascading restrictions coming from on this page? */
 118         public $mCascadeSources;
 119
 120         /** @var bool Boolean for initialisation on demand */
 121         public $mRestrictionsLoaded = false;
 122
 123         /** @var string Text form including namespace/interwiki, initialised on demand */
 124         protected $mPrefixedText = null;
 125
 126         /** @var mixed Cached value for getTitleProtection (create protection) */
 127         public $mTitleProtection;
 128
 129         /**
 130          * @var int Namespace index when there is no namespace. Don't change the
 131          *   following default, NS_MAIN is hardcoded in several places. See bug 696.
 132          *   Zero except in {{transclusion}} tags.
 133          */
 134         public $mDefaultNamespace = NS_MAIN;
 135
 136         /** @var int The page length, 0 for special pages */
 137         protected $mLength = -1;
 138
 139         /** @var null Is the article at this title a redirect? */
 140         public $mRedirect = null;
 141
 142         /** @var array Associative array of user ID -> timestamp/false */
 143         private $mNotificationTimestamp = [];
 144
 145         /** @var bool Whether a page has any subpages */
 146         private $mHasSubpages;
 147
 148         /** @var bool The (string) language code of the page's language and content code. */
 149         private $mPageLanguage = false;
 150
 151         /** @var string|bool|null The page language code from the database, null if not saved in
 152          * the database or false if not loaded, yet. */
 153         private $mDbPageLanguage = false;
 154
 155         /** @var TitleValue A corresponding TitleValue object */
 156         private $mTitleValue = null;
 157
 158         /** @var bool Would deleting this page be a big deletion? */
 159         private $mIsBigDeletion = null;
 160         // @}
 161
 162         /**
 163          * B/C kludge: provide a TitleParser for use by Title.
 164          * Ideally, Title would have no methods that need this.
 165          * Avoid usage of this singleton by using TitleValue
 166          * and the associated services when possible.
 167          *
 168          * @return MediaWikiTitleCodec
 169          */
 170         private static function getMediaWikiTitleCodec() {
 171                 global $wgContLang, $wgLocalInterwikis;
 172
 173                 static $titleCodec = null;
 174                 static $titleCodecFingerprint = null;
 175
 176                 // $wgContLang and $wgLocalInterwikis may change (especially while testing),
 177                 // make sure we are using the right one. To detect changes over the course
 178                 // of a request, we remember a fingerprint of the config used to create the
 179                 // codec singleton, and re-create it if the fingerprint doesn't match.
 180                 $fingerprint = spl_object_hash( $wgContLang ) . '|' . implode( '+', $wgLocalInterwikis );
 181
 182                 if ( $fingerprint !== $titleCodecFingerprint ) {
 183                         $titleCodec = null;
 184                 }
 185
 186                 if ( !$titleCodec ) {
 187                         $titleCodec = new MediaWikiTitleCodec(
 188                                 $wgContLang,
 189                                 GenderCache::singleton(),
 190                                 $wgLocalInterwikis
 191                         );
 192                         $titleCodecFingerprint = $fingerprint;
 193                 }
 194
 195                 return $titleCodec;
 196         }
 197
 198         /**
 199          * B/C kludge: provide a TitleParser for use by Title.
 200          * Ideally, Title would have no methods that need this.
 201          * Avoid usage of this singleton by using TitleValue
 202          * and the associated services when possible.
 203          *
 204          * @return TitleFormatter
 205          */
 206         private static function getTitleFormatter() {
 207                 // NOTE: we know that getMediaWikiTitleCodec() returns a MediaWikiTitleCodec,
 208                 //      which implements TitleFormatter.
 209                 return self::getMediaWikiTitleCodec();
 210         }
 211
 212         function __construct() {
 213         }
 214
 215         /**
 216          * Create a new Title from a prefixed DB key
 217          *
 218          * @param string $key The database key, which has underscores
 219          *      instead of spaces, possibly including namespace and
 220          *      interwiki prefixes
 221          * @return Title|null Title, or null on an error
 222          */
 223         public static function newFromDBkey( $key ) {
 224                 $t = new Title();
 225                 $t->mDbkeyform = $key;
 226
 227                 try {
 228                         $t->secureAndSplit();
 229                         return $t;
 230                 } catch ( MalformedTitleException $ex ) {
 231                         return null;
 232                 }
 233         }
 234
 235         /**
 236          * Create a new Title from a TitleValue
 237          *
 238          * @param TitleValue $titleValue Assumed to be safe.
 239          *
 240          * @return Title
 241          */
 242         public static function newFromTitleValue( TitleValue $titleValue ) {
 243                 return self::newFromLinkTarget( $titleValue );
 244         }
 245
 246         /**
 247          * Create a new Title from a LinkTarget
 248          *
 249          * @param LinkTarget $linkTarget Assumed to be safe.
 250          *
 251          * @return Title
 252          */
 253         public static function newFromLinkTarget( LinkTarget $linkTarget ) {
 254                 if ( $linkTarget instanceof Title ) {
 255                         // Special case if it's already a Title object
 256                         return $linkTarget;
 257                 }
 258                 return self::makeTitle(
 259                         $linkTarget->getNamespace(),
 260                         $linkTarget->getText(),
 261                         $linkTarget->getFragment(),
 262                         $linkTarget->getInterwiki()
 263                 );
 264         }
 265
 266         /**
 267          * Create a new Title from text, such as what one would find in a link. De-
 268          * codes any HTML entities in the text.
 269          *
 270          * @param string|int|null $text The link text; spaces, prefixes, and an
 271          *   initial ':' indicating the main namespace are accepted.
 272          * @param int $defaultNamespace The namespace to use if none is specified
 273          *   by a prefix.  If you want to force a specific namespace even if
 274          *   $text might begin with a namespace prefix, use makeTitle() or
 275          *   makeTitleSafe().
 276          * @throws InvalidArgumentException
 277          * @return Title|null Title or null on an error.
 278          */
 279         public static function newFromText( $text, $defaultNamespace = NS_MAIN ) {
 280                 // DWIM: Integers can be passed in here when page titles are used as array keys.
 281                 if ( $text !== null && !is_string( $text ) && !is_int( $text ) ) {
 282                         throw new InvalidArgumentException( '$text must be a string.' );
 283                 }
 284                 if ( $text === null ) {
 285                         return null;
 286                 }
 287
 288                 try {
 289                         return Title::newFromTextThrow( strval( $text ), $defaultNamespace );
 290                 } catch ( MalformedTitleException $ex ) {
 291                         return null;
 292                 }
 293         }
 294
 295         /**
 296          * Like Title::newFromText(), but throws MalformedTitleException when the title is invalid,
 297          * rather than returning null.
 298          *
 299          * The exception subclasses encode detailed information about why the title is invalid.
 300          *
 301          * @see Title::newFromText
 302          *
 303          * @since 1.25
 304          * @param string $text Title text to check
 305          * @param int $defaultNamespace
 306          * @throws MalformedTitleException If the title is invalid
 307          * @return Title
 308          */
 309         public static function newFromTextThrow( $text, $defaultNamespace = NS_MAIN ) {
 310                 if ( is_object( $text ) ) {
 311                         throw new MWException( '$text must be a string, given an object' );
 312                 }
 313
 314                 $titleCache = self::getTitleCache();
 315
 316                 // Wiki pages often contain multiple links to the same page.
 317                 // Title normalization and parsing can become expensive on pages with many
 318                 // links, so we can save a little time by caching them.
 319                 // In theory these are value objects and won't get changed...
 320                 if ( $defaultNamespace == NS_MAIN ) {
 321                         $t = $titleCache->get( $text );
 322                         if ( $t ) {
 323                                 return $t;
 324                         }
 325                 }
 326
 327                 // Convert things like &eacute; &#257; or &#x3017; into normalized (bug 14952) text
 328                 $filteredText = Sanitizer::decodeCharReferencesAndNormalize( $text );
 329
 330                 $t = new Title();
 331                 $t->mDbkeyform = strtr( $filteredText, ' ', '_' );
 332                 $t->mDefaultNamespace = intval( $defaultNamespace );
 333
 334                 $t->secureAndSplit();
 335                 if ( $defaultNamespace == NS_MAIN ) {
 336                         $titleCache->set( $text, $t );
 337                 }
 338                 return $t;
 339         }
 340
 341         /**
 342          * THIS IS NOT THE FUNCTION YOU WANT. Use Title::newFromText().
 343          *
 344          * Example of wrong and broken code:
 345          * $title = Title::newFromURL( $wgRequest->getVal( 'title' ) );
 346          *
 347          * Example of right code:
 348          * $title = Title::newFromText( $wgRequest->getVal( 'title' ) );
 349          *
 350          * Create a new Title from URL-encoded text. Ensures that
 351          * the given title's length does not exceed the maximum.
 352          *
 353          * @param string $url The title, as might be taken from a URL
 354          * @return Title|null The new object, or null on an error
 355          */
 356         public static function newFromURL( $url ) {
 357                 $t = new Title();
 358
 359                 # For compatibility with old buggy URLs. "+" is usually not valid in titles,
 360                 # but some URLs used it as a space replacement and they still come
 361                 # from some external search tools.
 362                 if ( strpos( self::legalChars(), '+' ) === false ) {
 363                         $url = strtr( $url, '+', ' ' );
 364                 }
 365
 366                 $t->mDbkeyform = strtr( $url, ' ', '_' );
 367
 368                 try {
 369                         $t->secureAndSplit();
 370                         return $t;
 371                 } catch ( MalformedTitleException $ex ) {
 372                         return null;
 373                 }
 374         }
 375
 376         /**
 377          * @return HashBagOStuff
 378          */
 379         private static function getTitleCache() {
 380                 if ( self::$titleCache == null ) {
 381                         self::$titleCache = new HashBagOStuff( [ 'maxKeys' => self::CACHE_MAX ] );
 382                 }
 383                 return self::$titleCache;
 384         }
 385
 386         /**
 387          * Returns a list of fields that are to be selected for initializing Title
 388          * objects or LinkCache entries. Uses $wgContentHandlerUseDB to determine
 389          * whether to include page_content_model.
 390          *
 391          * @return array
 392          */
 393         protected static function getSelectFields() {
 394                 global $wgContentHandlerUseDB, $wgPageLanguageUseDB;
 395
 396                 $fields = [
 397                         'page_namespace', 'page_title', 'page_id',
 398                         'page_len', 'page_is_redirect', 'page_latest',
 399                 ];
 400
 401                 if ( $wgContentHandlerUseDB ) {
 402                         $fields[] = 'page_content_model';
 403                 }
 404
 405                 if ( $wgPageLanguageUseDB ) {
 406                         $fields[] = 'page_lang';
 407                 }
 408
 409                 return $fields;
 410         }
 411
 412         /**
 413          * Create a new Title from an article ID
 414          *
 415          * @param int $id The page_id corresponding to the Title to create
 416          * @param int $flags Use Title::GAID_FOR_UPDATE to use master
 417          * @return Title|null The new object, or null on an error
 418          */
 419         public static function newFromID( $id, $flags = 0 ) {
 420                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
 421                 $row = $db->selectRow(
 422                         'page',
 423                         self::getSelectFields(),
 424                         [ 'page_id' => $id ],
 425                         __METHOD__
 426                 );
 427                 if ( $row !== false ) {
 428                         $title = Title::newFromRow( $row );
 429                 } else {
 430                         $title = null;
 431                 }
 432                 return $title;
 433         }
 434
 435         /**
 436          * Make an array of titles from an array of IDs
 437          *
 438          * @param int[] $ids Array of IDs
 439          * @return Title[] Array of Titles
 440          */
 441         public static function newFromIDs( $ids ) {
 442                 if ( !count( $ids ) ) {
 443                         return [];
 444                 }
 445                 $dbr = wfGetDB( DB_SLAVE );
 446
 447                 $res = $dbr->select(
 448                         'page',
 449                         self::getSelectFields(),
 450                         [ 'page_id' => $ids ],
 451                         __METHOD__
 452                 );
 453
 454                 $titles = [];
 455                 foreach ( $res as $row ) {
 456                         $titles[] = Title::newFromRow( $row );
 457                 }
 458                 return $titles;
 459         }
 460
 461         /**
 462          * Make a Title object from a DB row
 463          *
 464          * @param stdClass $row Object database row (needs at least page_title,page_namespace)
 465          * @return Title Corresponding Title
 466          */
 467         public static function newFromRow( $row ) {
 468                 $t = self::makeTitle( $row->page_namespace, $row->page_title );
 469                 $t->loadFromRow( $row );
 470                 return $t;
 471         }
 472
 473         /**
 474          * Load Title object fields from a DB row.
 475          * If false is given, the title will be treated as non-existing.
 476          *
 477          * @param stdClass|bool $row Database row
 478          */
 479         public function loadFromRow( $row ) {
 480                 if ( $row ) { // page found
 481                         if ( isset( $row->page_id ) ) {
 482                                 $this->mArticleID = (int)$row->page_id;
 483                         }
 484                         if ( isset( $row->page_len ) ) {
 485                                 $this->mLength = (int)$row->page_len;
 486                         }
 487                         if ( isset( $row->page_is_redirect ) ) {
 488                                 $this->mRedirect = (bool)$row->page_is_redirect;
 489                         }
 490                         if ( isset( $row->page_latest ) ) {
 491                                 $this->mLatestID = (int)$row->page_latest;
 492                         }
 493                         if ( isset( $row->page_content_model ) ) {
 494                                 $this->mContentModel = strval( $row->page_content_model );
 495                         } else {
 496                                 $this->mContentModel = false; # initialized lazily in getContentModel()
 497                         }
 498                         if ( isset( $row->page_lang ) ) {
 499                                 $this->mDbPageLanguage = (string)$row->page_lang;
 500                         }
 501                         if ( isset( $row->page_restrictions ) ) {
 502                                 $this->mOldRestrictions = $row->page_restrictions;
 503                         }
 504                 } else { // page not found
 505                         $this->mArticleID = 0;
 506                         $this->mLength = 0;
 507                         $this->mRedirect = false;
 508                         $this->mLatestID = 0;
 509                         $this->mContentModel = false; # initialized lazily in getContentModel()
 510                 }
 511         }
 512
 513         /**
 514          * Create a new Title from a namespace index and a DB key.
 515          * It's assumed that $ns and $title are *valid*, for instance when
 516          * they came directly from the database or a special page name.
 517          * For convenience, spaces are converted to underscores so that
 518          * eg user_text fields can be used directly.
 519          *
 520          * @param int $ns The namespace of the article
 521          * @param string $title The unprefixed database key form
 522          * @param string $fragment The link fragment (after the "#")
 523          * @param string $interwiki The interwiki prefix
 524          * @return Title The new object
 525          */
 526         public static function &makeTitle( $ns, $title, $fragment = '', $interwiki = '' ) {
 527                 $t = new Title();
 528                 $t->mInterwiki = $interwiki;
 529                 $t->mFragment = $fragment;
 530                 $t->mNamespace = $ns = intval( $ns );
 531                 $t->mDbkeyform = strtr( $title, ' ', '_' );
 532                 $t->mArticleID = ( $ns >= 0 ) ? -1 : 0;
 533                 $t->mUrlform = wfUrlencode( $t->mDbkeyform );
 534                 $t->mTextform = strtr( $title, '_', ' ' );
 535                 $t->mContentModel = false; # initialized lazily in getContentModel()
 536                 return $t;
 537         }
 538
 539         /**
 540          * Create a new Title from a namespace index and a DB key.
 541          * The parameters will be checked for validity, which is a bit slower
 542          * than makeTitle() but safer for user-provided data.
 543          *
 544          * @param int $ns The namespace of the article
 545          * @param string $title Database key form
 546          * @param string $fragment The link fragment (after the "#")
 547          * @param string $interwiki Interwiki prefix
 548          * @return Title|null The new object, or null on an error
 549          */
 550         public static function makeTitleSafe( $ns, $title, $fragment = '', $interwiki = '' ) {
 551                 if ( !MWNamespace::exists( $ns ) ) {
 552                         return null;
 553                 }
 554
 555                 $t = new Title();
 556                 $t->mDbkeyform = Title::makeName( $ns, $title, $fragment, $interwiki, true );
 557
 558                 try {
 559                         $t->secureAndSplit();
 560                         return $t;
 561                 } catch ( MalformedTitleException $ex ) {
 562                         return null;
 563                 }
 564         }
 565
 566         /**
 567          * Create a new Title for the Main Page
 568          *
 569          * @return Title The new object
 570          */
 571         public static function newMainPage() {
 572                 $title = Title::newFromText( wfMessage( 'mainpage' )->inContentLanguage()->text() );
 573                 // Don't give fatal errors if the message is broken
 574                 if ( !$title ) {
 575                         $title = Title::newFromText( 'Main Page' );
 576                 }
 577                 return $title;
 578         }
 579
 580         /**
 581          * Get the prefixed DB key associated with an ID
 582          *
 583          * @param int $id The page_id of the article
 584          * @return Title|null An object representing the article, or null if no such article was found
 585          */
 586         public static function nameOf( $id ) {
 587                 $dbr = wfGetDB( DB_SLAVE );
 588
 589                 $s = $dbr->selectRow(
 590                         'page',
 591                         [ 'page_namespace', 'page_title' ],
 592                         [ 'page_id' => $id ],
 593                         __METHOD__
 594                 );
 595                 if ( $s === false ) {
 596                         return null;
 597                 }
 598
 599                 $n = self::makeName( $s->page_namespace, $s->page_title );
 600                 return $n;
 601         }
 602
 603         /**
 604          * Get a regex character class describing the legal characters in a link
 605          *
 606          * @return string The list of characters, not delimited
 607          */
 608         public static function legalChars() {
 609                 global $wgLegalTitleChars;
 610                 return $wgLegalTitleChars;
 611         }
 612
 613         /**
 614          * Returns a simple regex that will match on characters and sequences invalid in titles.
 615          * Note that this doesn't pick up many things that could be wrong with titles, but that
 616          * replacing this regex with something valid will make many titles valid.
 617          *
 618          * @deprecated since 1.25, use MediaWikiTitleCodec::getTitleInvalidRegex() instead
 619          *
 620          * @return string Regex string
 621          */
 622         static function getTitleInvalidRegex() {
 623                 wfDeprecated( __METHOD__, '1.25' );
 624                 return MediaWikiTitleCodec::getTitleInvalidRegex();
 625         }
 626
 627         /**
 628          * Utility method for converting a character sequence from bytes to Unicode.
 629          *
 630          * Primary usecase being converting $wgLegalTitleChars to a sequence usable in
 631          * javascript, as PHP uses UTF-8 bytes where javascript uses Unicode code units.
 632          *
 633          * @param string $byteClass
 634          * @return string
 635          */
 636         public static function convertByteClassToUnicodeClass( $byteClass ) {
 637                 $length = strlen( $byteClass );
 638                 // Input token queue
 639                 $x0 = $x1 = $x2 = '';
 640                 // Decoded queue
 641                 $d0 = $d1 = $d2 = '';
 642                 // Decoded integer codepoints
 643                 $ord0 = $ord1 = $ord2 = 0;
 644                 // Re-encoded queue
 645                 $r0 = $r1 = $r2 = '';
 646                 // Output
 647                 $out = '';
 648                 // Flags
 649                 $allowUnicode = false;
 650                 for ( $pos = 0; $pos < $length; $pos++ ) {
 651                         // Shift the queues down
 652                         $x2 = $x1;
 653                         $x1 = $x0;
 654                         $d2 = $d1;
 655                         $d1 = $d0;
 656                         $ord2 = $ord1;
 657                         $ord1 = $ord0;
 658                         $r2 = $r1;
 659                         $r1 = $r0;
 660                         // Load the current input token and decoded values
 661                         $inChar = $byteClass[$pos];
 662                         if ( $inChar == '\\' ) {
 663                                 if ( preg_match( '/x([0-9a-fA-F]{2})/A', $byteClass, $m, 0, $pos + 1 ) ) {
 664                                         $x0 = $inChar . $m[0];
 665                                         $d0 = chr( hexdec( $m[1] ) );
 666                                         $pos += strlen( $m[0] );
 667                                 } elseif ( preg_match( '/[0-7]{3}/A', $byteClass, $m, 0, $pos + 1 ) ) {
 668                                         $x0 = $inChar . $m[0];
 669                                         $d0 = chr( octdec( $m[0] ) );
 670                                         $pos += strlen( $m[0] );
 671                                 } elseif ( $pos + 1 >= $length ) {
 672                                         $x0 = $d0 = '\\';
 673                                 } else {
 674                                         $d0 = $byteClass[$pos + 1];
 675                                         $x0 = $inChar . $d0;
 676                                         $pos += 1;
 677                                 }
 678                         } else {
 679                                 $x0 = $d0 = $inChar;
 680                         }
 681                         $ord0 = ord( $d0 );
 682                         // Load the current re-encoded value
 683                         if ( $ord0 < 32 || $ord0 == 0x7f ) {
 684                                 $r0 = sprintf( '\x%02x', $ord0 );
 685                         } elseif ( $ord0 >= 0x80 ) {
 686                                 // Allow unicode if a single high-bit character appears
 687                                 $r0 = sprintf( '\x%02x', $ord0 );
 688                                 $allowUnicode = true;
 689                         } elseif ( strpos( '-\\[]^', $d0 ) !== false ) {
 690                                 $r0 = '\\' . $d0;
 691                         } else {
 692                                 $r0 = $d0;
 693                         }
 694                         // Do the output
 695                         if ( $x0 !== '' && $x1 === '-' && $x2 !== '' ) {
 696                                 // Range
 697                                 if ( $ord2 > $ord0 ) {
 698                                         // Empty range
 699                                 } elseif ( $ord0 >= 0x80 ) {
 700                                         // Unicode range
 701                                         $allowUnicode = true;
 702                                         if ( $ord2 < 0x80 ) {
 703                                                 // Keep the non-unicode section of the range
 704                                                 $out .= "$r2-\\x7F";
 705                                         }
 706                                 } else {
 707                                         // Normal range
 708                                         $out .= "$r2-$r0";
 709                                 }
 710                                 // Reset state to the initial value
 711                                 $x0 = $x1 = $d0 = $d1 = $r0 = $r1 = '';
 712                         } elseif ( $ord2 < 0x80 ) {
 713                                 // ASCII character
 714                                 $out .= $r2;
 715                         }
 716                 }
 717                 if ( $ord1 < 0x80 ) {
 718                         $out .= $r1;
 719                 }
 720                 if ( $ord0 < 0x80 ) {
 721                         $out .= $r0;
 722                 }
 723                 if ( $allowUnicode ) {
 724                         $out .= '\u0080-\uFFFF';
 725                 }
 726                 return $out;
 727         }
 728
 729         /**
 730          * Make a prefixed DB key from a DB key and a namespace index
 731          *
 732          * @param int $ns Numerical representation of the namespace
 733          * @param string $title The DB key form the title
 734          * @param string $fragment The link fragment (after the "#")
 735          * @param string $interwiki The interwiki prefix
 736          * @param bool $canonicalNamespace If true, use the canonical name for
 737          *   $ns instead of the localized version.
 738          * @return string The prefixed form of the title
 739          */
 740         public static function makeName( $ns, $title, $fragment = '', $interwiki = '',
 741                 $canonicalNamespace = false
 742         ) {
 743                 global $wgContLang;
 744
 745                 if ( $canonicalNamespace ) {
 746                         $namespace = MWNamespace::getCanonicalName( $ns );
 747                 } else {
 748                         $namespace = $wgContLang->getNsText( $ns );
 749                 }
 750                 $name = $namespace == '' ? $title : "$namespace:$title";
 751                 if ( strval( $interwiki ) != '' ) {
 752                         $name = "$interwiki:$name";
 753                 }
 754                 if ( strval( $fragment ) != '' ) {
 755                         $name .= '#' . $fragment;
 756                 }
 757                 return $name;
 758         }
 759
 760         /**
 761          * Escape a text fragment, say from a link, for a URL
 762          *
 763          * @param string $fragment Containing a URL or link fragment (after the "#")
 764          * @return string Escaped string
 765          */
 766         static function escapeFragmentForURL( $fragment ) {
 767                 # Note that we don't urlencode the fragment.  urlencoded Unicode
 768                 # fragments appear not to work in IE (at least up to 7) or in at least
 769                 # one version of Opera 9.x.  The W3C validator, for one, doesn't seem
 770                 # to care if they aren't encoded.
 771                 return Sanitizer::escapeId( $fragment, 'noninitial' );
 772         }
 773
 774         /**
 775          * Callback for usort() to do title sorts by (namespace, title)
 776          *
 777          * @param Title $a
 778          * @param Title $b
 779          *
 780          * @return int Result of string comparison, or namespace comparison
 781          */
 782         public static function compare( $a, $b ) {
 783                 if ( $a->getNamespace() == $b->getNamespace() ) {
 784                         return strcmp( $a->getText(), $b->getText() );
 785                 } else {
 786                         return $a->getNamespace() - $b->getNamespace();
 787                 }
 788         }
 789
 790         /**
 791          * Determine whether the object refers to a page within
 792          * this project (either this wiki or a wiki with a local
 793          * interwiki, see https://www.mediawiki.org/wiki/Manual:Interwiki_table#iw_local )
 794          *
 795          * @return bool True if this is an in-project interwiki link or a wikilink, false otherwise
 796          */
 797         public function isLocal() {
 798                 if ( $this->isExternal() ) {
 799                         $iw = Interwiki::fetch( $this->mInterwiki );
 800                         if ( $iw ) {
 801                                 return $iw->isLocal();
 802                         }
 803                 }
 804                 return true;
 805         }
 806
 807         /**
 808          * Is this Title interwiki?
 809          *
 810          * @return bool
 811          */
 812         public function isExternal() {
 813                 return $this->mInterwiki !== '';
 814         }
 815
 816         /**
 817          * Get the interwiki prefix
 818          *
 819          * Use Title::isExternal to check if a interwiki is set
 820          *
 821          * @return string Interwiki prefix
 822          */
 823         public function getInterwiki() {
 824                 return $this->mInterwiki;
 825         }
 826
 827         /**
 828          * Was this a local interwiki link?
 829          *
 830          * @return bool
 831          */
 832         public function wasLocalInterwiki() {
 833                 return $this->mLocalInterwiki;
 834         }
 835
 836         /**
 837          * Determine whether the object refers to a page within
 838          * this project and is transcludable.
 839          *
 840          * @return bool True if this is transcludable
 841          */
 842         public function isTrans() {
 843                 if ( !$this->isExternal() ) {
 844                         return false;
 845                 }
 846
 847                 return Interwiki::fetch( $this->mInterwiki )->isTranscludable();
 848         }
 849
 850         /**
 851          * Returns the DB name of the distant wiki which owns the object.
 852          *
 853          * @return string The DB name
 854          */
 855         public function getTransWikiID() {
 856                 if ( !$this->isExternal() ) {
 857                         return false;
 858                 }
 859
 860                 return Interwiki::fetch( $this->mInterwiki )->getWikiID();
 861         }
 862
 863         /**
 864          * Get a TitleValue object representing this Title.
 865          *
 866          * @note Not all valid Titles have a corresponding valid TitleValue
 867          * (e.g. TitleValues cannot represent page-local links that have a
 868          * fragment but no title text).
 869          *
 870          * @return TitleValue|null
 871          */
 872         public function getTitleValue() {
 873                 if ( $this->mTitleValue === null ) {
 874                         try {
 875                                 $this->mTitleValue = new TitleValue(
 876                                         $this->getNamespace(),
 877                                         $this->getDBkey(),
 878                                         $this->getFragment(),
 879                                         $this->getInterwiki()
 880                                 );
 881                         } catch ( InvalidArgumentException $ex ) {
 882                                 wfDebug( __METHOD__ . ': Can\'t create a TitleValue for [[' .
 883                                         $this->getPrefixedText() . ']]: ' . $ex->getMessage() . "\n" );
 884                         }
 885                 }
 886
 887                 return $this->mTitleValue;
 888         }
 889
 890         /**
 891          * Get the text form (spaces not underscores) of the main part
 892          *
 893          * @return string Main part of the title
 894          */
 895         public function getText() {
 896                 return $this->mTextform;
 897         }
 898
 899         /**
 900          * Get the URL-encoded form of the main part
 901          *
 902          * @return string Main part of the title, URL-encoded
 903          */
 904         public function getPartialURL() {
 905                 return $this->mUrlform;
 906         }
 907
 908         /**
 909          * Get the main part with underscores
 910          *
 911          * @return string Main part of the title, with underscores
 912          */
 913         public function getDBkey() {
 914                 return $this->mDbkeyform;
 915         }
 916
 917         /**
 918          * Get the DB key with the initial letter case as specified by the user
 919          *
 920          * @return string DB key
 921          */
 922         function getUserCaseDBKey() {
 923                 if ( !is_null( $this->mUserCaseDBKey ) ) {
 924                         return $this->mUserCaseDBKey;
 925                 } else {
 926                         // If created via makeTitle(), $this->mUserCaseDBKey is not set.
 927                         return $this->mDbkeyform;
 928                 }
 929         }
 930
 931         /**
 932          * Get the namespace index, i.e. one of the NS_xxxx constants.
 933          *
 934          * @return int Namespace index
 935          */
 936         public function getNamespace() {
 937                 return $this->mNamespace;
 938         }
 939
 940         /**
 941          * Get the page's content model id, see the CONTENT_MODEL_XXX constants.
 942          *
 943          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
 944          * @return string Content model id
 945          */
 946         public function getContentModel( $flags = 0 ) {
 947                 if ( !$this->mContentModel && $this->getArticleID( $flags ) ) {
 948                         $linkCache = LinkCache::singleton();
 949                         $linkCache->addLinkObj( $this ); # in case we already had an article ID
 950                         $this->mContentModel = $linkCache->getGoodLinkFieldObj( $this, 'model' );
 951                 }
 952
 953                 if ( !$this->mContentModel ) {
 954                         $this->mContentModel = ContentHandler::getDefaultModelFor( $this );
 955                 }
 956
 957                 return $this->mContentModel;
 958         }
 959
 960         /**
 961          * Convenience method for checking a title's content model name
 962          *
 963          * @param string $id The content model ID (use the CONTENT_MODEL_XXX constants).
 964          * @return bool True if $this->getContentModel() == $id
 965          */
 966         public function hasContentModel( $id ) {
 967                 return $this->getContentModel() == $id;
 968         }
 969
 970         /**
 971          * Get the namespace text
 972          *
 973          * @return string Namespace text
 974          */
 975         public function getNsText() {
 976                 if ( $this->isExternal() ) {
 977                         // This probably shouldn't even happen,
 978                         // but for interwiki transclusion it sometimes does.
 979                         // Use the canonical namespaces if possible to try to
 980                         // resolve a foreign namespace.
 981                         if ( MWNamespace::exists( $this->mNamespace ) ) {
 982                                 return MWNamespace::getCanonicalName( $this->mNamespace );
 983                         }
 984                 }
 985
 986                 try {
 987                         $formatter = self::getTitleFormatter();
 988                         return $formatter->getNamespaceName( $this->mNamespace, $this->mDbkeyform );
 989                 } catch ( InvalidArgumentException $ex ) {
 990                         wfDebug( __METHOD__ . ': ' . $ex->getMessage() . "\n" );
 991                         return false;
 992                 }
 993         }
 994
 995         /**
 996          * Get the namespace text of the subject (rather than talk) page
 997          *
 998          * @return string Namespace text
 999          */
1000         public function getSubjectNsText() {
1001                 global $wgContLang;
1002                 return $wgContLang->getNsText( MWNamespace::getSubject( $this->mNamespace ) );
1003         }
1004
1005         /**
1006          * Get the namespace text of the talk page
1007          *
1008          * @return string Namespace text
1009          */
1010         public function getTalkNsText() {
1011                 global $wgContLang;
1012                 return $wgContLang->getNsText( MWNamespace::getTalk( $this->mNamespace ) );
1013         }
1014
1015         /**
1016          * Could this title have a corresponding talk page?
1017          *
1018          * @return bool
1019          */
1020         public function canTalk() {
1021                 return MWNamespace::canTalk( $this->mNamespace );
1022         }
1023
1024         /**
1025          * Is this in a namespace that allows actual pages?
1026          *
1027          * @return bool
1028          */
1029         public function canExist() {
1030                 return $this->mNamespace >= NS_MAIN;
1031         }
1032
1033         /**
1034          * Can this title be added to a user's watchlist?
1035          *
1036          * @return bool
1037          */
1038         public function isWatchable() {
1039                 return !$this->isExternal() && MWNamespace::isWatchable( $this->getNamespace() );
1040         }
1041
1042         /**
1043          * Returns true if this is a special page.
1044          *
1045          * @return bool
1046          */
1047         public function isSpecialPage() {
1048                 return $this->getNamespace() == NS_SPECIAL;
1049         }
1050
1051         /**
1052          * Returns true if this title resolves to the named special page
1053          *
1054          * @param string $name The special page name
1055          * @return bool
1056          */
1057         public function isSpecial( $name ) {
1058                 if ( $this->isSpecialPage() ) {
1059                         list( $thisName, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $this->getDBkey() );
1060                         if ( $name == $thisName ) {
1061                                 return true;
1062                         }
1063                 }
1064                 return false;
1065         }
1066
1067         /**
1068          * If the Title refers to a special page alias which is not the local default, resolve
1069          * the alias, and localise the name as necessary.  Otherwise, return $this
1070          *
1071          * @return Title
1072          */
1073         public function fixSpecialName() {
1074                 if ( $this->isSpecialPage() ) {
1075                         list( $canonicalName, $par ) = SpecialPageFactory::resolveAlias( $this->mDbkeyform );
1076                         if ( $canonicalName ) {
1077                                 $localName = SpecialPageFactory::getLocalNameFor( $canonicalName, $par );
1078                                 if ( $localName != $this->mDbkeyform ) {
1079                                         return Title::makeTitle( NS_SPECIAL, $localName );
1080                                 }
1081                         }
1082                 }
1083                 return $this;
1084         }
1085
1086         /**
1087          * Returns true if the title is inside the specified namespace.
1088          *
1089          * Please make use of this instead of comparing to getNamespace()
1090          * This function is much more resistant to changes we may make
1091          * to namespaces than code that makes direct comparisons.
1092          * @param int $ns The namespace
1093          * @return bool
1094          * @since 1.19
1095          */
1096         public function inNamespace( $ns ) {
1097                 return MWNamespace::equals( $this->getNamespace(), $ns );
1098         }
1099
1100         /**
1101          * Returns true if the title is inside one of the specified namespaces.
1102          *
1103          * @param int $namespaces,... The namespaces to check for
1104          * @return bool
1105          * @since 1.19
1106          */
1107         public function inNamespaces( /* ... */ ) {
1108                 $namespaces = func_get_args();
1109                 if ( count( $namespaces ) > 0 && is_array( $namespaces[0] ) ) {
1110                         $namespaces = $namespaces[0];
1111                 }
1112
1113                 foreach ( $namespaces as $ns ) {
1114                         if ( $this->inNamespace( $ns ) ) {
1115                                 return true;
1116                         }
1117                 }
1118
1119                 return false;
1120         }
1121
1122         /**
1123          * Returns true if the title has the same subject namespace as the
1124          * namespace specified.
1125          * For example this method will take NS_USER and return true if namespace
1126          * is either NS_USER or NS_USER_TALK since both of them have NS_USER
1127          * as their subject namespace.
1128          *
1129          * This is MUCH simpler than individually testing for equivalence
1130          * against both NS_USER and NS_USER_TALK, and is also forward compatible.
1131          * @since 1.19
1132          * @param int $ns
1133          * @return bool
1134          */
1135         public function hasSubjectNamespace( $ns ) {
1136                 return MWNamespace::subjectEquals( $this->getNamespace(), $ns );
1137         }
1138
1139         /**
1140          * Is this Title in a namespace which contains content?
1141          * In other words, is this a content page, for the purposes of calculating
1142          * statistics, etc?
1143          *
1144          * @return bool
1145          */
1146         public function isContentPage() {
1147                 return MWNamespace::isContent( $this->getNamespace() );
1148         }
1149
1150         /**
1151          * Would anybody with sufficient privileges be able to move this page?
1152          * Some pages just aren't movable.
1153          *
1154          * @return bool
1155          */
1156         public function isMovable() {
1157                 if ( !MWNamespace::isMovable( $this->getNamespace() ) || $this->isExternal() ) {
1158                         // Interwiki title or immovable namespace. Hooks don't get to override here
1159                         return false;
1160                 }
1161
1162                 $result = true;
1163                 Hooks::run( 'TitleIsMovable', [ $this, &$result ] );
1164                 return $result;
1165         }
1166
1167         /**
1168          * Is this the mainpage?
1169          * @note Title::newFromText seems to be sufficiently optimized by the title
1170          * cache that we don't need to over-optimize by doing direct comparisons and
1171          * accidentally creating new bugs where $title->equals( Title::newFromText() )
1172          * ends up reporting something differently than $title->isMainPage();
1173          *
1174          * @since 1.18
1175          * @return bool
1176          */
1177         public function isMainPage() {
1178                 return $this->equals( Title::newMainPage() );
1179         }
1180
1181         /**
1182          * Is this a subpage?
1183          *
1184          * @return bool
1185          */
1186         public function isSubpage() {
1187                 return MWNamespace::hasSubpages( $this->mNamespace )
1188                         ? strpos( $this->getText(), '/' ) !== false
1189                         : false;
1190         }
1191
1192         /**
1193          * Is this a conversion table for the LanguageConverter?
1194          *
1195          * @return bool
1196          */
1197         public function isConversionTable() {
1198                 // @todo ConversionTable should become a separate content model.
1199
1200                 return $this->getNamespace() == NS_MEDIAWIKI &&
1201                         strpos( $this->getText(), 'Conversiontable/' ) === 0;
1202         }
1203
1204         /**
1205          * Does that page contain wikitext, or it is JS, CSS or whatever?
1206          *
1207          * @return bool
1208          */
1209         public function isWikitextPage() {
1210                 return $this->hasContentModel( CONTENT_MODEL_WIKITEXT );
1211         }
1212
1213         /**
1214          * Could this page contain custom CSS or JavaScript for the global UI.
1215          * This is generally true for pages in the MediaWiki namespace having CONTENT_MODEL_CSS
1216          * or CONTENT_MODEL_JAVASCRIPT.
1217          *
1218          * This method does *not* return true for per-user JS/CSS. Use isCssJsSubpage()
1219          * for that!
1220          *
1221          * Note that this method should not return true for pages that contain and
1222          * show "inactive" CSS or JS.
1223          *
1224          * @return bool
1225          * @todo FIXME: Rename to isSiteConfigPage() and remove deprecated hook
1226          */
1227         public function isCssOrJsPage() {
1228                 $isCssOrJsPage = NS_MEDIAWIKI == $this->mNamespace
1229                         && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1230                                 || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1231
1232                 # @note This hook is also called in ContentHandler::getDefaultModel.
1233                 #   It's called here again to make sure hook functions can force this
1234                 #   method to return true even outside the MediaWiki namespace.
1235
1236                 Hooks::run( 'TitleIsCssOrJsPage', [ $this, &$isCssOrJsPage ], '1.25' );
1237
1238                 return $isCssOrJsPage;
1239         }
1240
1241         /**
1242          * Is this a .css or .js subpage of a user page?
1243          * @return bool
1244          * @todo FIXME: Rename to isUserConfigPage()
1245          */
1246         public function isCssJsSubpage() {
1247                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1248                                 && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1249                                         || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) ) );
1250         }
1251
1252         /**
1253          * Trim down a .css or .js subpage title to get the corresponding skin name
1254          *
1255          * @return string Containing skin name from .css or .js subpage title
1256          */
1257         public function getSkinFromCssJsSubpage() {
1258                 $subpage = explode( '/', $this->mTextform );
1259                 $subpage = $subpage[count( $subpage ) - 1];
1260                 $lastdot = strrpos( $subpage, '.' );
1261                 if ( $lastdot === false ) {
1262                         return $subpage; # Never happens: only called for names ending in '.css' or '.js'
1263                 }
1264                 return substr( $subpage, 0, $lastdot );
1265         }
1266
1267         /**
1268          * Is this a .css subpage of a user page?
1269          *
1270          * @return bool
1271          */
1272         public function isCssSubpage() {
1273                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1274                         && $this->hasContentModel( CONTENT_MODEL_CSS ) );
1275         }
1276
1277         /**
1278          * Is this a .js subpage of a user page?
1279          *
1280          * @return bool
1281          */
1282         public function isJsSubpage() {
1283                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1284                         && $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1285         }
1286
1287         /**
1288          * Is this a talk page of some sort?
1289          *
1290          * @return bool
1291          */
1292         public function isTalkPage() {
1293                 return MWNamespace::isTalk( $this->getNamespace() );
1294         }
1295
1296         /**
1297          * Get a Title object associated with the talk page of this article
1298          *
1299          * @return Title The object for the talk page
1300          */
1301         public function getTalkPage() {
1302                 return Title::makeTitle( MWNamespace::getTalk( $this->getNamespace() ), $this->getDBkey() );
1303         }
1304
1305         /**
1306          * Get a title object associated with the subject page of this
1307          * talk page
1308          *
1309          * @return Title The object for the subject page
1310          */
1311         public function getSubjectPage() {
1312                 // Is this the same title?
1313                 $subjectNS = MWNamespace::getSubject( $this->getNamespace() );
1314                 if ( $this->getNamespace() == $subjectNS ) {
1315                         return $this;
1316                 }
1317                 return Title::makeTitle( $subjectNS, $this->getDBkey() );
1318         }
1319
1320         /**
1321          * Get the other title for this page, if this is a subject page
1322          * get the talk page, if it is a subject page get the talk page
1323          *
1324          * @since 1.25
1325          * @throws MWException
1326          * @return Title
1327          */
1328         public function getOtherPage() {
1329                 if ( $this->isSpecialPage() ) {
1330                         throw new MWException( 'Special pages cannot have other pages' );
1331                 }
1332                 if ( $this->isTalkPage() ) {
1333                         return $this->getSubjectPage();
1334                 } else {
1335                         return $this->getTalkPage();
1336                 }
1337         }
1338
1339         /**
1340          * Get the default namespace index, for when there is no namespace
1341          *
1342          * @return int Default namespace index
1343          */
1344         public function getDefaultNamespace() {
1345                 return $this->mDefaultNamespace;
1346         }
1347
1348         /**
1349          * Get the Title fragment (i.e.\ the bit after the #) in text form
1350          *
1351          * Use Title::hasFragment to check for a fragment
1352          *
1353          * @return string Title fragment
1354          */
1355         public function getFragment() {
1356                 return $this->mFragment;
1357         }
1358
1359         /**
1360          * Check if a Title fragment is set
1361          *
1362          * @return bool
1363          * @since 1.23
1364          */
1365         public function hasFragment() {
1366                 return $this->mFragment !== '';
1367         }
1368
1369         /**
1370          * Get the fragment in URL form, including the "#" character if there is one
1371          * @return string Fragment in URL form
1372          */
1373         public function getFragmentForURL() {
1374                 if ( !$this->hasFragment() ) {
1375                         return '';
1376                 } else {
1377                         return '#' . Title::escapeFragmentForURL( $this->getFragment() );
1378                 }
1379         }
1380
1381         /**
1382          * Set the fragment for this title. Removes the first character from the
1383          * specified fragment before setting, so it assumes you're passing it with
1384          * an initial "#".
1385          *
1386          * Deprecated for public use, use Title::makeTitle() with fragment parameter,
1387          * or Title::createFragmentTarget().
1388          * Still in active use privately.
1389          *
1390          * @private
1391          * @param string $fragment Text
1392          */
1393         public function setFragment( $fragment ) {
1394                 $this->mFragment = strtr( substr( $fragment, 1 ), '_', ' ' );
1395         }
1396
1397         /**
1398          * Creates a new Title for a different fragment of the same page.
1399          *
1400          * @since 1.27
1401          * @param string $fragment
1402          * @return Title
1403          */
1404         public function createFragmentTarget( $fragment ) {
1405                 return self::makeTitle(
1406                         $this->getNamespace(),
1407                         $this->getText(),
1408                         $fragment,
1409                         $this->getInterwiki()
1410                 );
1411
1412         }
1413
1414         /**
1415          * Prefix some arbitrary text with the namespace or interwiki prefix
1416          * of this object
1417          *
1418          * @param string $name The text
1419          * @return string The prefixed text
1420          */
1421         private function prefix( $name ) {
1422                 $p = '';
1423                 if ( $this->isExternal() ) {
1424                         $p = $this->mInterwiki . ':';
1425                 }
1426
1427                 if ( 0 != $this->mNamespace ) {
1428                         $p .= $this->getNsText() . ':';
1429                 }
1430                 return $p . $name;
1431         }
1432
1433         /**
1434          * Get the prefixed database key form
1435          *
1436          * @return string The prefixed title, with underscores and
1437          *  any interwiki and namespace prefixes
1438          */
1439         public function getPrefixedDBkey() {
1440                 $s = $this->prefix( $this->mDbkeyform );
1441                 $s = strtr( $s, ' ', '_' );
1442                 return $s;
1443         }
1444
1445         /**
1446          * Get the prefixed title with spaces.
1447          * This is the form usually used for display
1448          *
1449          * @return string The prefixed title, with spaces
1450          */
1451         public function getPrefixedText() {
1452                 if ( $this->mPrefixedText === null ) {
1453                         $s = $this->prefix( $this->mTextform );
1454                         $s = strtr( $s, '_', ' ' );
1455                         $this->mPrefixedText = $s;
1456                 }
1457                 return $this->mPrefixedText;
1458         }
1459
1460         /**
1461          * Return a string representation of this title
1462          *
1463          * @return string Representation of this title
1464          */
1465         public function __toString() {
1466                 return $this->getPrefixedText();
1467         }
1468
1469         /**
1470          * Get the prefixed title with spaces, plus any fragment
1471          * (part beginning with '#')
1472          *
1473          * @return string The prefixed title, with spaces and the fragment, including '#'
1474          */
1475         public function getFullText() {
1476                 $text = $this->getPrefixedText();
1477                 if ( $this->hasFragment() ) {
1478                         $text .= '#' . $this->getFragment();
1479                 }
1480                 return $text;
1481         }
1482
1483         /**
1484          * Get the root page name text without a namespace, i.e. the leftmost part before any slashes
1485          *
1486          * @par Example:
1487          * @code
1488          * Title::newFromText('User:Foo/Bar/Baz')->getRootText();
1489          * # returns: 'Foo'
1490          * @endcode
1491          *
1492          * @return string Root name
1493          * @since 1.20
1494          */
1495         public function getRootText() {
1496                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1497                         return $this->getText();
1498                 }
1499
1500                 return strtok( $this->getText(), '/' );
1501         }
1502
1503         /**
1504          * Get the root page name title, i.e. the leftmost part before any slashes
1505          *
1506          * @par Example:
1507          * @code
1508          * Title::newFromText('User:Foo/Bar/Baz')->getRootTitle();
1509          * # returns: Title{User:Foo}
1510          * @endcode
1511          *
1512          * @return Title Root title
1513          * @since 1.20
1514          */
1515         public function getRootTitle() {
1516                 return Title::makeTitle( $this->getNamespace(), $this->getRootText() );
1517         }
1518
1519         /**
1520          * Get the base page name without a namespace, i.e. the part before the subpage name
1521          *
1522          * @par Example:
1523          * @code
1524          * Title::newFromText('User:Foo/Bar/Baz')->getBaseText();
1525          * # returns: 'Foo/Bar'
1526          * @endcode
1527          *
1528          * @return string Base name
1529          */
1530         public function getBaseText() {
1531                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1532                         return $this->getText();
1533                 }
1534
1535                 $parts = explode( '/', $this->getText() );
1536                 # Don't discard the real title if there's no subpage involved
1537                 if ( count( $parts ) > 1 ) {
1538                         unset( $parts[count( $parts ) - 1] );
1539                 }
1540                 return implode( '/', $parts );
1541         }
1542
1543         /**
1544          * Get the base page name title, i.e. the part before the subpage name
1545          *
1546          * @par Example:
1547          * @code
1548          * Title::newFromText('User:Foo/Bar/Baz')->getBaseTitle();
1549          * # returns: Title{User:Foo/Bar}
1550          * @endcode
1551          *
1552          * @return Title Base title
1553          * @since 1.20
1554          */
1555         public function getBaseTitle() {
1556                 return Title::makeTitle( $this->getNamespace(), $this->getBaseText() );
1557         }
1558
1559         /**
1560          * Get the lowest-level subpage name, i.e. the rightmost part after any slashes
1561          *
1562          * @par Example:
1563          * @code
1564          * Title::newFromText('User:Foo/Bar/Baz')->getSubpageText();
1565          * # returns: "Baz"
1566          * @endcode
1567          *
1568          * @return string Subpage name
1569          */
1570         public function getSubpageText() {
1571                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1572                         return $this->mTextform;
1573                 }
1574                 $parts = explode( '/', $this->mTextform );
1575                 return $parts[count( $parts ) - 1];
1576         }
1577
1578         /**
1579          * Get the title for a subpage of the current page
1580          *
1581          * @par Example:
1582          * @code
1583          * Title::newFromText('User:Foo/Bar/Baz')->getSubpage("Asdf");
1584          * # returns: Title{User:Foo/Bar/Baz/Asdf}
1585          * @endcode
1586          *
1587          * @param string $text The subpage name to add to the title
1588          * @return Title Subpage title
1589          * @since 1.20
1590          */
1591         public function getSubpage( $text ) {
1592                 return Title::makeTitleSafe( $this->getNamespace(), $this->getText() . '/' . $text );
1593         }
1594
1595         /**
1596          * Get a URL-encoded form of the subpage text
1597          *
1598          * @return string URL-encoded subpage name
1599          */
1600         public function getSubpageUrlForm() {
1601                 $text = $this->getSubpageText();
1602                 $text = wfUrlencode( strtr( $text, ' ', '_' ) );
1603                 return $text;
1604         }
1605
1606         /**
1607          * Get a URL-encoded title (not an actual URL) including interwiki
1608          *
1609          * @return string The URL-encoded form
1610          */
1611         public function getPrefixedURL() {
1612                 $s = $this->prefix( $this->mDbkeyform );
1613                 $s = wfUrlencode( strtr( $s, ' ', '_' ) );
1614                 return $s;
1615         }
1616
1617         /**
1618          * Helper to fix up the get{Canonical,Full,Link,Local,Internal}URL args
1619          * get{Canonical,Full,Link,Local,Internal}URL methods accepted an optional
1620          * second argument named variant. This was deprecated in favor
1621          * of passing an array of option with a "variant" key
1622          * Once $query2 is removed for good, this helper can be dropped
1623          * and the wfArrayToCgi moved to getLocalURL();
1624          *
1625          * @since 1.19 (r105919)
1626          * @param array|string $query
1627          * @param bool $query2
1628          * @return string
1629          */
1630         private static function fixUrlQueryArgs( $query, $query2 = false ) {
1631                 if ( $query2 !== false ) {
1632                         wfDeprecated( "Title::get{Canonical,Full,Link,Local,Internal}URL " .
1633                                 "method called with a second parameter is deprecated. Add your " .
1634                                 "parameter to an array passed as the first parameter.", "1.19" );
1635                 }
1636                 if ( is_array( $query ) ) {
1637                         $query = wfArrayToCgi( $query );
1638                 }
1639                 if ( $query2 ) {
1640                         if ( is_string( $query2 ) ) {
1641                                 // $query2 is a string, we will consider this to be
1642                                 // a deprecated $variant argument and add it to the query
1643                                 $query2 = wfArrayToCgi( [ 'variant' => $query2 ] );
1644                         } else {
1645                                 $query2 = wfArrayToCgi( $query2 );
1646                         }
1647                         // If we have $query content add a & to it first
1648                         if ( $query ) {
1649                                 $query .= '&';
1650                         }
1651                         // Now append the queries together
1652                         $query .= $query2;
1653                 }
1654                 return $query;
1655         }
1656
1657         /**
1658          * Get a real URL referring to this title, with interwiki link and
1659          * fragment
1660          *
1661          * @see self::getLocalURL for the arguments.
1662          * @see wfExpandUrl
1663          * @param array|string $query
1664          * @param bool $query2
1665          * @param string $proto Protocol type to use in URL
1666          * @return string The URL
1667          */
1668         public function getFullURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1669                 $query = self::fixUrlQueryArgs( $query, $query2 );
1670
1671                 # Hand off all the decisions on urls to getLocalURL
1672                 $url = $this->getLocalURL( $query );
1673
1674                 # Expand the url to make it a full url. Note that getLocalURL has the
1675                 # potential to output full urls for a variety of reasons, so we use
1676                 # wfExpandUrl instead of simply prepending $wgServer
1677                 $url = wfExpandUrl( $url, $proto );
1678
1679                 # Finally, add the fragment.
1680                 $url .= $this->getFragmentForURL();
1681
1682                 Hooks::run( 'GetFullURL', [ &$this, &$url, $query ] );
1683                 return $url;
1684         }
1685
1686         /**
1687          * Get a URL with no fragment or server name (relative URL) from a Title object.
1688          * If this page is generated with action=render, however,
1689          * $wgServer is prepended to make an absolute URL.
1690          *
1691          * @see self::getFullURL to always get an absolute URL.
1692          * @see self::getLinkURL to always get a URL that's the simplest URL that will be
1693          *  valid to link, locally, to the current Title.
1694          * @see self::newFromText to produce a Title object.
1695          *
1696          * @param string|array $query An optional query string,
1697          *   not used for interwiki links. Can be specified as an associative array as well,
1698          *   e.g., array( 'action' => 'edit' ) (keys and values will be URL-escaped).
1699          *   Some query patterns will trigger various shorturl path replacements.
1700          * @param array $query2 An optional secondary query array. This one MUST
1701          *   be an array. If a string is passed it will be interpreted as a deprecated
1702          *   variant argument and urlencoded into a variant= argument.
1703          *   This second query argument will be added to the $query
1704          *   The second parameter is deprecated since 1.19. Pass it as a key,value
1705          *   pair in the first parameter array instead.
1706          *
1707          * @return string String of the URL.
1708          */
1709         public function getLocalURL( $query = '', $query2 = false ) {
1710                 global $wgArticlePath, $wgScript, $wgServer, $wgRequest;
1711
1712                 $query = self::fixUrlQueryArgs( $query, $query2 );
1713
1714                 $interwiki = Interwiki::fetch( $this->mInterwiki );
1715                 if ( $interwiki ) {
1716                         $namespace = $this->getNsText();
1717                         if ( $namespace != '' ) {
1718                                 # Can this actually happen? Interwikis shouldn't be parsed.
1719                                 # Yes! It can in interwiki transclusion. But... it probably shouldn't.
1720                                 $namespace .= ':';
1721                         }
1722                         $url = $interwiki->getURL( $namespace . $this->getDBkey() );
1723                         $url = wfAppendQuery( $url, $query );
1724                 } else {
1725                         $dbkey = wfUrlencode( $this->getPrefixedDBkey() );
1726                         if ( $query == '' ) {
1727                                 $url = str_replace( '$1', $dbkey, $wgArticlePath );
1728                                 Hooks::run( 'GetLocalURL::Article', [ &$this, &$url ] );
1729                         } else {
1730                                 global $wgVariantArticlePath, $wgActionPaths, $wgContLang;
1731                                 $url = false;
1732                                 $matches = [];
1733
1734                                 if ( !empty( $wgActionPaths )
1735                                         && preg_match( '/^(.*&|)action=([^&]*)(&(.*)|)$/', $query, $matches )
1736                                 ) {
1737                                         $action = urldecode( $matches[2] );
1738                                         if ( isset( $wgActionPaths[$action] ) ) {
1739                                                 $query = $matches[1];
1740                                                 if ( isset( $matches[4] ) ) {
1741                                                         $query .= $matches[4];
1742                                                 }
1743                                                 $url = str_replace( '$1', $dbkey, $wgActionPaths[$action] );
1744                                                 if ( $query != '' ) {
1745                                                         $url = wfAppendQuery( $url, $query );
1746                                                 }
1747                                         }
1748                                 }
1749
1750                                 if ( $url === false
1751                                         && $wgVariantArticlePath
1752                                         && $wgContLang->getCode() === $this->getPageLanguage()->getCode()
1753                                         && $this->getPageLanguage()->hasVariants()
1754                                         && preg_match( '/^variant=([^&]*)$/', $query, $matches )
1755                                 ) {
1756                                         $variant = urldecode( $matches[1] );
1757                                         if ( $this->getPageLanguage()->hasVariant( $variant ) ) {
1758                                                 // Only do the variant replacement if the given variant is a valid
1759                                                 // variant for the page's language.
1760                                                 $url = str_replace( '$2', urlencode( $variant ), $wgVariantArticlePath );
1761                                                 $url = str_replace( '$1', $dbkey, $url );
1762                                         }
1763                                 }
1764
1765                                 if ( $url === false ) {
1766                                         if ( $query == '-' ) {
1767                                                 $query = '';
1768                                         }
1769                                         $url = "{$wgScript}?title={$dbkey}&{$query}";
1770                                 }
1771                         }
1772
1773                         Hooks::run( 'GetLocalURL::Internal', [ &$this, &$url, $query ] );
1774
1775                         // @todo FIXME: This causes breakage in various places when we
1776                         // actually expected a local URL and end up with dupe prefixes.
1777                         if ( $wgRequest->getVal( 'action' ) == 'render' ) {
1778                                 $url = $wgServer . $url;
1779                         }
1780                 }
1781                 Hooks::run( 'GetLocalURL', [ &$this, &$url, $query ] );
1782                 return $url;
1783         }
1784
1785         /**
1786          * Get a URL that's the simplest URL that will be valid to link, locally,
1787          * to the current Title.  It includes the fragment, but does not include
1788          * the server unless action=render is used (or the link is external).  If
1789          * there's a fragment but the prefixed text is empty, we just return a link
1790          * to the fragment.
1791          *
1792          * The result obviously should not be URL-escaped, but does need to be
1793          * HTML-escaped if it's being output in HTML.
1794          *
1795          * @param array $query
1796          * @param bool $query2
1797          * @param string $proto Protocol to use; setting this will cause a full URL to be used
1798          * @see self::getLocalURL for the arguments.
1799          * @return string The URL
1800          */
1801         public function getLinkURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1802                 if ( $this->isExternal() || $proto !== PROTO_RELATIVE ) {
1803                         $ret = $this->getFullURL( $query, $query2, $proto );
1804                 } elseif ( $this->getPrefixedText() === '' && $this->hasFragment() ) {
1805                         $ret = $this->getFragmentForURL();
1806                 } else {
1807                         $ret = $this->getLocalURL( $query, $query2 ) . $this->getFragmentForURL();
1808                 }
1809                 return $ret;
1810         }
1811
1812         /**
1813          * Get the URL form for an internal link.
1814          * - Used in various CDN-related code, in case we have a different
1815          * internal hostname for the server from the exposed one.
1816          *
1817          * This uses $wgInternalServer to qualify the path, or $wgServer
1818          * if $wgInternalServer is not set. If the server variable used is
1819          * protocol-relative, the URL will be expanded to http://
1820          *
1821          * @see self::getLocalURL for the arguments.
1822          * @return string The URL
1823          */
1824         public function getInternalURL( $query = '', $query2 = false ) {
1825                 global $wgInternalServer, $wgServer;
1826                 $query = self::fixUrlQueryArgs( $query, $query2 );
1827                 $server = $wgInternalServer !== false ? $wgInternalServer : $wgServer;
1828                 $url = wfExpandUrl( $server . $this->getLocalURL( $query ), PROTO_HTTP );
1829                 Hooks::run( 'GetInternalURL', [ &$this, &$url, $query ] );
1830                 return $url;
1831         }
1832
1833         /**
1834          * Get the URL for a canonical link, for use in things like IRC and
1835          * e-mail notifications. Uses $wgCanonicalServer and the
1836          * GetCanonicalURL hook.
1837          *
1838          * NOTE: Unlike getInternalURL(), the canonical URL includes the fragment
1839          *
1840          * @see self::getLocalURL for the arguments.
1841          * @return string The URL
1842          * @since 1.18
1843          */
1844         public function getCanonicalURL( $query = '', $query2 = false ) {
1845                 $query = self::fixUrlQueryArgs( $query, $query2 );
1846                 $url = wfExpandUrl( $this->getLocalURL( $query ) . $this->getFragmentForURL(), PROTO_CANONICAL );
1847                 Hooks::run( 'GetCanonicalURL', [ &$this, &$url, $query ] );
1848                 return $url;
1849         }
1850
1851         /**
1852          * Get the edit URL for this Title
1853          *
1854          * @return string The URL, or a null string if this is an interwiki link
1855          */
1856         public function getEditURL() {
1857                 if ( $this->isExternal() ) {
1858                         return '';
1859                 }
1860                 $s = $this->getLocalURL( 'action=edit' );
1861
1862                 return $s;
1863         }
1864
1865         /**
1866          * Can $user perform $action on this page?
1867          * This skips potentially expensive cascading permission checks
1868          * as well as avoids expensive error formatting
1869          *
1870          * Suitable for use for nonessential UI controls in common cases, but
1871          * _not_ for functional access control.
1872          *
1873          * May provide false positives, but should never provide a false negative.
1874          *
1875          * @param string $action Action that permission needs to be checked for
1876          * @param User $user User to check (since 1.19); $wgUser will be used if not provided.
1877          * @return bool
1878          */
1879         public function quickUserCan( $action, $user = null ) {
1880                 return $this->userCan( $action, $user, false );
1881         }
1882
1883         /**
1884          * Can $user perform $action on this page?
1885          *
1886          * @param string $action Action that permission needs to be checked for
1887          * @param User $user User to check (since 1.19); $wgUser will be used if not
1888          *   provided.
1889          * @param string $rigor Same format as Title::getUserPermissionsErrors()
1890          * @return bool
1891          */
1892         public function userCan( $action, $user = null, $rigor = 'secure' ) {
1893                 if ( !$user instanceof User ) {
1894                         global $wgUser;
1895                         $user = $wgUser;
1896                 }
1897
1898                 return !count( $this->getUserPermissionsErrorsInternal( $action, $user, $rigor, true ) );
1899         }
1900
1901         /**
1902          * Can $user perform $action on this page?
1903          *
1904          * @todo FIXME: This *does not* check throttles (User::pingLimiter()).
1905          *
1906          * @param string $action Action that permission needs to be checked for
1907          * @param User $user User to check
1908          * @param string $rigor One of (quick,full,secure)
1909          *   - quick  : does cheap permission checks from slaves (usable for GUI creation)
1910          *   - full   : does cheap and expensive checks possibly from a slave
1911          *   - secure : does cheap and expensive checks, using the master as needed
1912          * @param array $ignoreErrors Array of Strings Set this to a list of message keys
1913          *   whose corresponding errors may be ignored.
1914          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
1915          */
1916         public function getUserPermissionsErrors(
1917                 $action, $user, $rigor = 'secure', $ignoreErrors = []
1918         ) {
1919                 $errors = $this->getUserPermissionsErrorsInternal( $action, $user, $rigor );
1920
1921                 // Remove the errors being ignored.
1922                 foreach ( $errors as $index => $error ) {
1923                         $errKey = is_array( $error ) ? $error[0] : $error;
1924
1925                         if ( in_array( $errKey, $ignoreErrors ) ) {
1926                                 unset( $errors[$index] );
1927                         }
1928                         if ( $errKey instanceof MessageSpecifier && in_array( $errKey->getKey(), $ignoreErrors ) ) {
1929                                 unset( $errors[$index] );
1930                         }
1931                 }
1932
1933                 return $errors;
1934         }
1935
1936         /**
1937          * Permissions checks that fail most often, and which are easiest to test.
1938          *
1939          * @param string $action The action to check
1940          * @param User $user User to check
1941          * @param array $errors List of current errors
1942          * @param string $rigor Same format as Title::getUserPermissionsErrors()
1943          * @param bool $short Short circuit on first error
1944          *
1945          * @return array List of errors
1946          */
1947         private function checkQuickPermissions( $action, $user, $errors, $rigor, $short ) {
1948                 if ( !Hooks::run( 'TitleQuickPermissions',
1949                         [ $this, $user, $action, &$errors, ( $rigor !== 'quick' ), $short ] )
1950                 ) {
1951                         return $errors;
1952                 }
1953
1954                 if ( $action == 'create' ) {
1955                         if (
1956                                 ( $this->isTalkPage() && !$user->isAllowed( 'createtalk' ) ) ||
1957                                 ( !$this->isTalkPage() && !$user->isAllowed( 'createpage' ) )
1958                         ) {
1959                                 $errors[] = $user->isAnon() ? [ 'nocreatetext' ] : [ 'nocreate-loggedin' ];
1960                         }
1961                 } elseif ( $action == 'move' ) {
1962                         if ( !$user->isAllowed( 'move-rootuserpages' )
1963                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
1964                                 // Show user page-specific message only if the user can move other pages
1965                                 $errors[] = [ 'cant-move-user-page' ];
1966                         }
1967
1968                         // Check if user is allowed to move files if it's a file
1969                         if ( $this->mNamespace == NS_FILE && !$user->isAllowed( 'movefile' ) ) {
1970                                 $errors[] = [ 'movenotallowedfile' ];
1971                         }
1972
1973                         // Check if user is allowed to move category pages if it's a category page
1974                         if ( $this->mNamespace == NS_CATEGORY && !$user->isAllowed( 'move-categorypages' ) ) {
1975                                 $errors[] = [ 'cant-move-category-page' ];
1976                         }
1977
1978                         if ( !$user->isAllowed( 'move' ) ) {
1979                                 // User can't move anything
1980                                 $userCanMove = User::groupHasPermission( 'user', 'move' );
1981                                 $autoconfirmedCanMove = User::groupHasPermission( 'autoconfirmed', 'move' );
1982                                 if ( $user->isAnon() && ( $userCanMove || $autoconfirmedCanMove ) ) {
1983                                         // custom message if logged-in users without any special rights can move
1984                                         $errors[] = [ 'movenologintext' ];
1985                                 } else {
1986                                         $errors[] = [ 'movenotallowed' ];
1987                                 }
1988                         }
1989                 } elseif ( $action == 'move-target' ) {
1990                         if ( !$user->isAllowed( 'move' ) ) {
1991                                 // User can't move anything
1992                                 $errors[] = [ 'movenotallowed' ];
1993                         } elseif ( !$user->isAllowed( 'move-rootuserpages' )
1994                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
1995                                 // Show user page-specific message only if the user can move other pages
1996                                 $errors[] = [ 'cant-move-to-user-page' ];
1997                         } elseif ( !$user->isAllowed( 'move-categorypages' )
1998                                         && $this->mNamespace == NS_CATEGORY ) {
1999                                 // Show category page-specific message only if the user can move other pages
2000                                 $errors[] = [ 'cant-move-to-category-page' ];
2001                         }
2002                 } elseif ( !$user->isAllowed( $action ) ) {
2003                         $errors[] = $this->missingPermissionError( $action, $short );
2004                 }
2005
2006                 return $errors;
2007         }
2008
2009         /**
2010          * Add the resulting error code to the errors array
2011          *
2012          * @param array $errors List of current errors
2013          * @param array $result Result of errors
2014          *
2015          * @return array List of errors
2016          */
2017         private function resultToError( $errors, $result ) {
2018                 if ( is_array( $result ) && count( $result ) && !is_array( $result[0] ) ) {
2019                         // A single array representing an error
2020                         $errors[] = $result;
2021                 } elseif ( is_array( $result ) && is_array( $result[0] ) ) {
2022                         // A nested array representing multiple errors
2023                         $errors = array_merge( $errors, $result );
2024                 } elseif ( $result !== '' && is_string( $result ) ) {
2025                         // A string representing a message-id
2026                         $errors[] = [ $result ];
2027                 } elseif ( $result instanceof MessageSpecifier ) {
2028                         // A message specifier representing an error
2029                         $errors[] = [ $result ];
2030                 } elseif ( $result === false ) {
2031                         // a generic "We don't want them to do that"
2032                         $errors[] = [ 'badaccess-group0' ];
2033                 }
2034                 return $errors;
2035         }
2036
2037         /**
2038          * Check various permission hooks
2039          *
2040          * @param string $action The action to check
2041          * @param User $user User to check
2042          * @param array $errors List of current errors
2043          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2044          * @param bool $short Short circuit on first error
2045          *
2046          * @return array List of errors
2047          */
2048         private function checkPermissionHooks( $action, $user, $errors, $rigor, $short ) {
2049                 // Use getUserPermissionsErrors instead
2050                 $result = '';
2051                 if ( !Hooks::run( 'userCan', [ &$this, &$user, $action, &$result ] ) ) {
2052                         return $result ? [] : [ [ 'badaccess-group0' ] ];
2053                 }
2054                 // Check getUserPermissionsErrors hook
2055                 if ( !Hooks::run( 'getUserPermissionsErrors', [ &$this, &$user, $action, &$result ] ) ) {
2056                         $errors = $this->resultToError( $errors, $result );
2057                 }
2058                 // Check getUserPermissionsErrorsExpensive hook
2059                 if (
2060                         $rigor !== 'quick'
2061                         && !( $short && count( $errors ) > 0 )
2062                         && !Hooks::run( 'getUserPermissionsErrorsExpensive', [ &$this, &$user, $action, &$result ] )
2063                 ) {
2064                         $errors = $this->resultToError( $errors, $result );
2065                 }
2066
2067                 return $errors;
2068         }
2069
2070         /**
2071          * Check permissions on special pages & namespaces
2072          *
2073          * @param string $action The action to check
2074          * @param User $user User to check
2075          * @param array $errors List of current errors
2076          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2077          * @param bool $short Short circuit on first error
2078          *
2079          * @return array List of errors
2080          */
2081         private function checkSpecialsAndNSPermissions( $action, $user, $errors, $rigor, $short ) {
2082                 # Only 'createaccount' can be performed on special pages,
2083                 # which don't actually exist in the DB.
2084                 if ( NS_SPECIAL == $this->mNamespace && $action !== 'createaccount' ) {
2085                         $errors[] = [ 'ns-specialprotected' ];
2086                 }
2087
2088                 # Check $wgNamespaceProtection for restricted namespaces
2089                 if ( $this->isNamespaceProtected( $user ) ) {
2090                         $ns = $this->mNamespace == NS_MAIN ?
2091                                 wfMessage( 'nstab-main' )->text() : $this->getNsText();
2092                         $errors[] = $this->mNamespace == NS_MEDIAWIKI ?
2093                                 [ 'protectedinterface', $action ] : [ 'namespaceprotected', $ns, $action ];
2094                 }
2095
2096                 return $errors;
2097         }
2098
2099         /**
2100          * Check CSS/JS sub-page permissions
2101          *
2102          * @param string $action The action to check
2103          * @param User $user User to check
2104          * @param array $errors List of current errors
2105          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2106          * @param bool $short Short circuit on first error
2107          *
2108          * @return array List of errors
2109          */
2110         private function checkCSSandJSPermissions( $action, $user, $errors, $rigor, $short ) {
2111                 # Protect css/js subpages of user pages
2112                 # XXX: this might be better using restrictions
2113                 # XXX: right 'editusercssjs' is deprecated, for backward compatibility only
2114                 if ( $action != 'patrol' && !$user->isAllowed( 'editusercssjs' ) ) {
2115                         if ( preg_match( '/^' . preg_quote( $user->getName(), '/' ) . '\//', $this->mTextform ) ) {
2116                                 if ( $this->isCssSubpage() && !$user->isAllowedAny( 'editmyusercss', 'editusercss' ) ) {
2117                                         $errors[] = [ 'mycustomcssprotected', $action ];
2118                                 } elseif ( $this->isJsSubpage() && !$user->isAllowedAny( 'editmyuserjs', 'edituserjs' ) ) {
2119                                         $errors[] = [ 'mycustomjsprotected', $action ];
2120                                 }
2121                         } else {
2122                                 if ( $this->isCssSubpage() && !$user->isAllowed( 'editusercss' ) ) {
2123                                         $errors[] = [ 'customcssprotected', $action ];
2124                                 } elseif ( $this->isJsSubpage() && !$user->isAllowed( 'edituserjs' ) ) {
2125                                         $errors[] = [ 'customjsprotected', $action ];
2126                                 }
2127                         }
2128                 }
2129
2130                 return $errors;
2131         }
2132
2133         /**
2134          * Check against page_restrictions table requirements on this
2135          * page. The user must possess all required rights for this
2136          * action.
2137          *
2138          * @param string $action The action to check
2139          * @param User $user User to check
2140          * @param array $errors List of current errors
2141          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2142          * @param bool $short Short circuit on first error
2143          *
2144          * @return array List of errors
2145          */
2146         private function checkPageRestrictions( $action, $user, $errors, $rigor, $short ) {
2147                 foreach ( $this->getRestrictions( $action ) as $right ) {
2148                         // Backwards compatibility, rewrite sysop -> editprotected
2149                         if ( $right == 'sysop' ) {
2150                                 $right = 'editprotected';
2151                         }
2152                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2153                         if ( $right == 'autoconfirmed' ) {
2154                                 $right = 'editsemiprotected';
2155                         }
2156                         if ( $right == '' ) {
2157                                 continue;
2158                         }
2159                         if ( !$user->isAllowed( $right ) ) {
2160                                 $errors[] = [ 'protectedpagetext', $right, $action ];
2161                         } elseif ( $this->mCascadeRestriction && !$user->isAllowed( 'protect' ) ) {
2162                                 $errors[] = [ 'protectedpagetext', 'protect', $action ];
2163                         }
2164                 }
2165
2166                 return $errors;
2167         }
2168
2169         /**
2170          * Check restrictions on cascading pages.
2171          *
2172          * @param string $action The action to check
2173          * @param User $user User to check
2174          * @param array $errors List of current errors
2175          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2176          * @param bool $short Short circuit on first error
2177          *
2178          * @return array List of errors
2179          */
2180         private function checkCascadingSourcesRestrictions( $action, $user, $errors, $rigor, $short ) {
2181                 if ( $rigor !== 'quick' && !$this->isCssJsSubpage() ) {
2182                         # We /could/ use the protection level on the source page, but it's
2183                         # fairly ugly as we have to establish a precedence hierarchy for pages
2184                         # included by multiple cascade-protected pages. So just restrict
2185                         # it to people with 'protect' permission, as they could remove the
2186                         # protection anyway.
2187                         list( $cascadingSources, $restrictions ) = $this->getCascadeProtectionSources();
2188                         # Cascading protection depends on more than this page...
2189                         # Several cascading protected pages may include this page...
2190                         # Check each cascading level
2191                         # This is only for protection restrictions, not for all actions
2192                         if ( isset( $restrictions[$action] ) ) {
2193                                 foreach ( $restrictions[$action] as $right ) {
2194                                         // Backwards compatibility, rewrite sysop -> editprotected
2195                                         if ( $right == 'sysop' ) {
2196                                                 $right = 'editprotected';
2197                                         }
2198                                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2199                                         if ( $right == 'autoconfirmed' ) {
2200                                                 $right = 'editsemiprotected';
2201                                         }
2202                                         if ( $right != '' && !$user->isAllowedAll( 'protect', $right ) ) {
2203                                                 $pages = '';
2204                                                 foreach ( $cascadingSources as $page ) {
2205                                                         $pages .= '* [[:' . $page->getPrefixedText() . "]]\n";
2206                                                 }
2207                                                 $errors[] = [ 'cascadeprotected', count( $cascadingSources ), $pages, $action ];
2208                                         }
2209                                 }
2210                         }
2211                 }
2212
2213                 return $errors;
2214         }
2215
2216         /**
2217          * Check action permissions not already checked in checkQuickPermissions
2218          *
2219          * @param string $action The action to check
2220          * @param User $user User to check
2221          * @param array $errors List of current errors
2222          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2223          * @param bool $short Short circuit on first error
2224          *
2225          * @return array List of errors
2226          */
2227         private function checkActionPermissions( $action, $user, $errors, $rigor, $short ) {
2228                 global $wgDeleteRevisionsLimit, $wgLang;
2229
2230                 if ( $action == 'protect' ) {
2231                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit', $user, $rigor, true ) ) ) {
2232                                 // If they can't edit, they shouldn't protect.
2233                                 $errors[] = [ 'protect-cantedit' ];
2234                         }
2235                 } elseif ( $action == 'create' ) {
2236                         $title_protection = $this->getTitleProtection();
2237                         if ( $title_protection ) {
2238                                 if ( $title_protection['permission'] == ''
2239                                         || !$user->isAllowed( $title_protection['permission'] )
2240                                 ) {
2241                                         $errors[] = [
2242                                                 'titleprotected',
2243                                                 User::whoIs( $title_protection['user'] ),
2244                                                 $title_protection['reason']
2245                                         ];
2246                                 }
2247                         }
2248                 } elseif ( $action == 'move' ) {
2249                         // Check for immobile pages
2250                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2251                                 // Specific message for this case
2252                                 $errors[] = [ 'immobile-source-namespace', $this->getNsText() ];
2253                         } elseif ( !$this->isMovable() ) {
2254                                 // Less specific message for rarer cases
2255                                 $errors[] = [ 'immobile-source-page' ];
2256                         }
2257                 } elseif ( $action == 'move-target' ) {
2258                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2259                                 $errors[] = [ 'immobile-target-namespace', $this->getNsText() ];
2260                         } elseif ( !$this->isMovable() ) {
2261                                 $errors[] = [ 'immobile-target-page' ];
2262                         }
2263                 } elseif ( $action == 'delete' ) {
2264                         $tempErrors = $this->checkPageRestrictions( 'edit', $user, [], $rigor, true );
2265                         if ( !$tempErrors ) {
2266                                 $tempErrors = $this->checkCascadingSourcesRestrictions( 'edit',
2267                                         $user, $tempErrors, $rigor, true );
2268                         }
2269                         if ( $tempErrors ) {
2270                                 // If protection keeps them from editing, they shouldn't be able to delete.
2271                                 $errors[] = [ 'deleteprotected' ];
2272                         }
2273                         if ( $rigor !== 'quick' && $wgDeleteRevisionsLimit
2274                                 && !$this->userCan( 'bigdelete', $user ) && $this->isBigDeletion()
2275                         ) {
2276                                 $errors[] = [ 'delete-toobig', $wgLang->formatNum( $wgDeleteRevisionsLimit ) ];
2277                         }
2278                 }
2279                 return $errors;
2280         }
2281
2282         /**
2283          * Check that the user isn't blocked from editing.
2284          *
2285          * @param string $action The action to check
2286          * @param User $user User to check
2287          * @param array $errors List of current errors
2288          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2289          * @param bool $short Short circuit on first error
2290          *
2291          * @return array List of errors
2292          */
2293         private function checkUserBlock( $action, $user, $errors, $rigor, $short ) {
2294                 // Account creation blocks handled at userlogin.
2295                 // Unblocking handled in SpecialUnblock
2296                 if ( $rigor === 'quick' || in_array( $action, [ 'createaccount', 'unblock' ] ) ) {
2297                         return $errors;
2298                 }
2299
2300                 global $wgEmailConfirmToEdit;
2301
2302                 if ( $wgEmailConfirmToEdit && !$user->isEmailConfirmed() ) {
2303                         $errors[] = [ 'confirmedittext' ];
2304                 }
2305
2306                 $useSlave = ( $rigor !== 'secure' );
2307                 if ( ( $action == 'edit' || $action == 'create' )
2308                         && !$user->isBlockedFrom( $this, $useSlave )
2309                 ) {
2310                         // Don't block the user from editing their own talk page unless they've been
2311                         // explicitly blocked from that too.
2312                 } elseif ( $user->isBlocked() && $user->getBlock()->prevents( $action ) !== false ) {
2313                         // @todo FIXME: Pass the relevant context into this function.
2314                         $errors[] = $user->getBlock()->getPermissionsError( RequestContext::getMain() );
2315                 }
2316
2317                 return $errors;
2318         }
2319
2320         /**
2321          * Check that the user is allowed to read this page.
2322          *
2323          * @param string $action The action to check
2324          * @param User $user User to check
2325          * @param array $errors List of current errors
2326          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2327          * @param bool $short Short circuit on first error
2328          *
2329          * @return array List of errors
2330          */
2331         private function checkReadPermissions( $action, $user, $errors, $rigor, $short ) {
2332                 global $wgWhitelistRead, $wgWhitelistReadRegexp;
2333
2334                 $whitelisted = false;
2335                 if ( User::isEveryoneAllowed( 'read' ) ) {
2336                         # Shortcut for public wikis, allows skipping quite a bit of code
2337                         $whitelisted = true;
2338                 } elseif ( $user->isAllowed( 'read' ) ) {
2339                         # If the user is allowed to read pages, he is allowed to read all pages
2340                         $whitelisted = true;
2341                 } elseif ( $this->isSpecial( 'Userlogin' )
2342                         || $this->isSpecial( 'ChangePassword' )
2343                         || $this->isSpecial( 'PasswordReset' )
2344                 ) {
2345                         # Always grant access to the login page.
2346                         # Even anons need to be able to log in.
2347                         $whitelisted = true;
2348                 } elseif ( is_array( $wgWhitelistRead ) && count( $wgWhitelistRead ) ) {
2349                         # Time to check the whitelist
2350                         # Only do these checks is there's something to check against
2351                         $name = $this->getPrefixedText();
2352                         $dbName = $this->getPrefixedDBkey();
2353
2354                         // Check for explicit whitelisting with and without underscores
2355                         if ( in_array( $name, $wgWhitelistRead, true ) || in_array( $dbName, $wgWhitelistRead, true ) ) {
2356                                 $whitelisted = true;
2357                         } elseif ( $this->getNamespace() == NS_MAIN ) {
2358                                 # Old settings might have the title prefixed with
2359                                 # a colon for main-namespace pages
2360                                 if ( in_array( ':' . $name, $wgWhitelistRead ) ) {
2361                                         $whitelisted = true;
2362                                 }
2363                         } elseif ( $this->isSpecialPage() ) {
2364                                 # If it's a special page, ditch the subpage bit and check again
2365                                 $name = $this->getDBkey();
2366                                 list( $name, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $name );
2367                                 if ( $name ) {
2368                                         $pure = SpecialPage::getTitleFor( $name )->getPrefixedText();
2369                                         if ( in_array( $pure, $wgWhitelistRead, true ) ) {
2370                                                 $whitelisted = true;
2371                                         }
2372                                 }
2373                         }
2374                 }
2375
2376                 if ( !$whitelisted && is_array( $wgWhitelistReadRegexp ) && !empty( $wgWhitelistReadRegexp ) ) {
2377                         $name = $this->getPrefixedText();
2378                         // Check for regex whitelisting
2379                         foreach ( $wgWhitelistReadRegexp as $listItem ) {
2380                                 if ( preg_match( $listItem, $name ) ) {
2381                                         $whitelisted = true;
2382                                         break;
2383                                 }
2384                         }
2385                 }
2386
2387                 if ( !$whitelisted ) {
2388                         # If the title is not whitelisted, give extensions a chance to do so...
2389                         Hooks::run( 'TitleReadWhitelist', [ $this, $user, &$whitelisted ] );
2390                         if ( !$whitelisted ) {
2391                                 $errors[] = $this->missingPermissionError( $action, $short );
2392                         }
2393                 }
2394
2395                 return $errors;
2396         }
2397
2398         /**
2399          * Get a description array when the user doesn't have the right to perform
2400          * $action (i.e. when User::isAllowed() returns false)
2401          *
2402          * @param string $action The action to check
2403          * @param bool $short Short circuit on first error
2404          * @return array List of errors
2405          */
2406         private function missingPermissionError( $action, $short ) {
2407                 // We avoid expensive display logic for quickUserCan's and such
2408                 if ( $short ) {
2409                         return [ 'badaccess-group0' ];
2410                 }
2411
2412                 $groups = array_map( [ 'User', 'makeGroupLinkWiki' ],
2413                         User::getGroupsWithPermission( $action ) );
2414
2415                 if ( count( $groups ) ) {
2416                         global $wgLang;
2417                         return [
2418                                 'badaccess-groups',
2419                                 $wgLang->commaList( $groups ),
2420                                 count( $groups )
2421                         ];
2422                 } else {
2423                         return [ 'badaccess-group0' ];
2424                 }
2425         }
2426
2427         /**
2428          * Can $user perform $action on this page? This is an internal function,
2429          * with multiple levels of checks depending on performance needs; see $rigor below.
2430          * It does not check wfReadOnly().
2431          *
2432          * @param string $action Action that permission needs to be checked for
2433          * @param User $user User to check
2434          * @param string $rigor One of (quick,full,secure)
2435          *   - quick  : does cheap permission checks from slaves (usable for GUI creation)
2436          *   - full   : does cheap and expensive checks possibly from a slave
2437          *   - secure : does cheap and expensive checks, using the master as needed
2438          * @param bool $short Set this to true to stop after the first permission error.
2439          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
2440          */
2441         protected function getUserPermissionsErrorsInternal(
2442                 $action, $user, $rigor = 'secure', $short = false
2443         ) {
2444                 if ( $rigor === true ) {
2445                         $rigor = 'secure'; // b/c
2446                 } elseif ( $rigor === false ) {
2447                         $rigor = 'quick'; // b/c
2448                 } elseif ( !in_array( $rigor, [ 'quick', 'full', 'secure' ] ) ) {
2449                         throw new Exception( "Invalid rigor parameter '$rigor'." );
2450                 }
2451
2452                 # Read has special handling
2453                 if ( $action == 'read' ) {
2454                         $checks = [
2455                                 'checkPermissionHooks',
2456                                 'checkReadPermissions',
2457                         ];
2458                 # Don't call checkSpecialsAndNSPermissions or checkCSSandJSPermissions
2459                 # here as it will lead to duplicate error messages. This is okay to do
2460                 # since anywhere that checks for create will also check for edit, and
2461                 # those checks are called for edit.
2462                 } elseif ( $action == 'create' ) {
2463                         $checks = [
2464                                 'checkQuickPermissions',
2465                                 'checkPermissionHooks',
2466                                 'checkPageRestrictions',
2467                                 'checkCascadingSourcesRestrictions',
2468                                 'checkActionPermissions',
2469                                 'checkUserBlock'
2470                         ];
2471                 } else {
2472                         $checks = [
2473                                 'checkQuickPermissions',
2474                                 'checkPermissionHooks',
2475                                 'checkSpecialsAndNSPermissions',
2476                                 'checkCSSandJSPermissions',
2477                                 'checkPageRestrictions',
2478                                 'checkCascadingSourcesRestrictions',
2479                                 'checkActionPermissions',
2480                                 'checkUserBlock'
2481                         ];
2482                 }
2483
2484                 $errors = [];
2485                 while ( count( $checks ) > 0 &&
2486                                 !( $short && count( $errors ) > 0 ) ) {
2487                         $method = array_shift( $checks );
2488                         $errors = $this->$method( $action, $user, $errors, $rigor, $short );
2489                 }
2490
2491                 return $errors;
2492         }
2493
2494         /**
2495          * Get a filtered list of all restriction types supported by this wiki.
2496          * @param bool $exists True to get all restriction types that apply to
2497          * titles that do exist, False for all restriction types that apply to
2498          * titles that do not exist
2499          * @return array
2500          */
2501         public static function getFilteredRestrictionTypes( $exists = true ) {
2502                 global $wgRestrictionTypes;
2503                 $types = $wgRestrictionTypes;
2504                 if ( $exists ) {
2505                         # Remove the create restriction for existing titles
2506                         $types = array_diff( $types, [ 'create' ] );
2507                 } else {
2508                         # Only the create and upload restrictions apply to non-existing titles
2509                         $types = array_intersect( $types, [ 'create', 'upload' ] );
2510                 }
2511                 return $types;
2512         }
2513
2514         /**
2515          * Returns restriction types for the current Title
2516          *
2517          * @return array Applicable restriction types
2518          */
2519         public function getRestrictionTypes() {
2520                 if ( $this->isSpecialPage() ) {
2521                         return [];
2522                 }
2523
2524                 $types = self::getFilteredRestrictionTypes( $this->exists() );
2525
2526                 if ( $this->getNamespace() != NS_FILE ) {
2527                         # Remove the upload restriction for non-file titles
2528                         $types = array_diff( $types, [ 'upload' ] );
2529                 }
2530
2531                 Hooks::run( 'TitleGetRestrictionTypes', [ $this, &$types ] );
2532
2533                 wfDebug( __METHOD__ . ': applicable restrictions to [[' .
2534                         $this->getPrefixedText() . ']] are {' . implode( ',', $types ) . "}\n" );
2535
2536                 return $types;
2537         }
2538
2539         /**
2540          * Is this title subject to title protection?
2541          * Title protection is the one applied against creation of such title.
2542          *
2543          * @return array|bool An associative array representing any existent title
2544          *   protection, or false if there's none.
2545          */
2546         public function getTitleProtection() {
2547                 // Can't protect pages in special namespaces
2548                 if ( $this->getNamespace() < 0 ) {
2549                         return false;
2550                 }
2551
2552                 // Can't protect pages that exist.
2553                 if ( $this->exists() ) {
2554                         return false;
2555                 }
2556
2557                 if ( $this->mTitleProtection === null ) {
2558                         $dbr = wfGetDB( DB_SLAVE );
2559                         $res = $dbr->select(
2560                                 'protected_titles',
2561                                 [
2562                                         'user' => 'pt_user',
2563                                         'reason' => 'pt_reason',
2564                                         'expiry' => 'pt_expiry',
2565                                         'permission' => 'pt_create_perm'
2566                                 ],
2567                                 [ 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ],
2568                                 __METHOD__
2569                         );
2570
2571                         // fetchRow returns false if there are no rows.
2572                         $row = $dbr->fetchRow( $res );
2573                         if ( $row ) {
2574                                 if ( $row['permission'] == 'sysop' ) {
2575                                         $row['permission'] = 'editprotected'; // B/C
2576                                 }
2577                                 if ( $row['permission'] == 'autoconfirmed' ) {
2578                                         $row['permission'] = 'editsemiprotected'; // B/C
2579                                 }
2580                                 $row['expiry'] = $dbr->decodeExpiry( $row['expiry'] );
2581                         }
2582                         $this->mTitleProtection = $row;
2583                 }
2584                 return $this->mTitleProtection;
2585         }
2586
2587         /**
2588          * Remove any title protection due to page existing
2589          */
2590         public function deleteTitleProtection() {
2591                 $dbw = wfGetDB( DB_MASTER );
2592
2593                 $dbw->delete(
2594                         'protected_titles',
2595                         [ 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ],
2596                         __METHOD__
2597                 );
2598                 $this->mTitleProtection = false;
2599         }
2600
2601         /**
2602          * Is this page "semi-protected" - the *only* protection levels are listed
2603          * in $wgSemiprotectedRestrictionLevels?
2604          *
2605          * @param string $action Action to check (default: edit)
2606          * @return bool
2607          */
2608         public function isSemiProtected( $action = 'edit' ) {
2609                 global $wgSemiprotectedRestrictionLevels;
2610
2611                 $restrictions = $this->getRestrictions( $action );
2612                 $semi = $wgSemiprotectedRestrictionLevels;
2613                 if ( !$restrictions || !$semi ) {
2614                         // Not protected, or all protection is full protection
2615                         return false;
2616                 }
2617
2618                 // Remap autoconfirmed to editsemiprotected for BC
2619                 foreach ( array_keys( $semi, 'autoconfirmed' ) as $key ) {
2620                         $semi[$key] = 'editsemiprotected';
2621                 }
2622                 foreach ( array_keys( $restrictions, 'autoconfirmed' ) as $key ) {
2623                         $restrictions[$key] = 'editsemiprotected';
2624                 }
2625
2626                 return !array_diff( $restrictions, $semi );
2627         }
2628
2629         /**
2630          * Does the title correspond to a protected article?
2631          *
2632          * @param string $action The action the page is protected from,
2633          * by default checks all actions.
2634          * @return bool
2635          */
2636         public function isProtected( $action = '' ) {
2637                 global $wgRestrictionLevels;
2638
2639                 $restrictionTypes = $this->getRestrictionTypes();
2640
2641                 # Special pages have inherent protection
2642                 if ( $this->isSpecialPage() ) {
2643                         return true;
2644                 }
2645
2646                 # Check regular protection levels
2647                 foreach ( $restrictionTypes as $type ) {
2648                         if ( $action == $type || $action == '' ) {
2649                                 $r = $this->getRestrictions( $type );
2650                                 foreach ( $wgRestrictionLevels as $level ) {
2651                                         if ( in_array( $level, $r ) && $level != '' ) {
2652                                                 return true;
2653                                         }
2654                                 }
2655                         }
2656                 }
2657
2658                 return false;
2659         }
2660
2661         /**
2662          * Determines if $user is unable to edit this page because it has been protected
2663          * by $wgNamespaceProtection.
2664          *
2665          * @param User $user User object to check permissions
2666          * @return bool
2667          */
2668         public function isNamespaceProtected( User $user ) {
2669                 global $wgNamespaceProtection;
2670
2671                 if ( isset( $wgNamespaceProtection[$this->mNamespace] ) ) {
2672                         foreach ( (array)$wgNamespaceProtection[$this->mNamespace] as $right ) {
2673                                 if ( $right != '' && !$user->isAllowed( $right ) ) {
2674                                         return true;
2675                                 }
2676                         }
2677                 }
2678                 return false;
2679         }
2680
2681         /**
2682          * Cascading protection: Return true if cascading restrictions apply to this page, false if not.
2683          *
2684          * @return bool If the page is subject to cascading restrictions.
2685          */
2686         public function isCascadeProtected() {
2687                 list( $sources, /* $restrictions */ ) = $this->getCascadeProtectionSources( false );
2688                 return ( $sources > 0 );
2689         }
2690
2691         /**
2692          * Determines whether cascading protection sources have already been loaded from
2693          * the database.
2694          *
2695          * @param bool $getPages True to check if the pages are loaded, or false to check
2696          * if the status is loaded.
2697          * @return bool Whether or not the specified information has been loaded
2698          * @since 1.23
2699          */
2700         public function areCascadeProtectionSourcesLoaded( $getPages = true ) {
2701                 return $getPages ? $this->mCascadeSources !== null : $this->mHasCascadingRestrictions !== null;
2702         }
2703
2704         /**
2705          * Cascading protection: Get the source of any cascading restrictions on this page.
2706          *
2707          * @param bool $getPages Whether or not to retrieve the actual pages
2708          *        that the restrictions have come from and the actual restrictions
2709          *        themselves.
2710          * @return array Two elements: First is an array of Title objects of the
2711          *        pages from which cascading restrictions have come, false for
2712          *        none, or true if such restrictions exist but $getPages was not
2713          *        set. Second is an array like that returned by
2714          *        Title::getAllRestrictions(), or an empty array if $getPages is
2715          *        false.
2716          */
2717         public function getCascadeProtectionSources( $getPages = true ) {
2718                 $pagerestrictions = [];
2719
2720                 if ( $this->mCascadeSources !== null && $getPages ) {
2721                         return [ $this->mCascadeSources, $this->mCascadingRestrictions ];
2722                 } elseif ( $this->mHasCascadingRestrictions !== null && !$getPages ) {
2723                         return [ $this->mHasCascadingRestrictions, $pagerestrictions ];
2724                 }
2725
2726                 $dbr = wfGetDB( DB_SLAVE );
2727
2728                 if ( $this->getNamespace() == NS_FILE ) {
2729                         $tables = [ 'imagelinks', 'page_restrictions' ];
2730                         $where_clauses = [
2731                                 'il_to' => $this->getDBkey(),
2732                                 'il_from=pr_page',
2733                                 'pr_cascade' => 1
2734                         ];
2735                 } else {
2736                         $tables = [ 'templatelinks', 'page_restrictions' ];
2737                         $where_clauses = [
2738                                 'tl_namespace' => $this->getNamespace(),
2739                                 'tl_title' => $this->getDBkey(),
2740                                 'tl_from=pr_page',
2741                                 'pr_cascade' => 1
2742                         ];
2743                 }
2744
2745                 if ( $getPages ) {
2746                         $cols = [ 'pr_page', 'page_namespace', 'page_title',
2747                                 'pr_expiry', 'pr_type', 'pr_level' ];
2748                         $where_clauses[] = 'page_id=pr_page';
2749                         $tables[] = 'page';
2750                 } else {
2751                         $cols = [ 'pr_expiry' ];
2752                 }
2753
2754                 $res = $dbr->select( $tables, $cols, $where_clauses, __METHOD__ );
2755
2756                 $sources = $getPages ? [] : false;
2757                 $now = wfTimestampNow();
2758
2759                 foreach ( $res as $row ) {
2760                         $expiry = $dbr->decodeExpiry( $row->pr_expiry );
2761                         if ( $expiry > $now ) {
2762                                 if ( $getPages ) {
2763                                         $page_id = $row->pr_page;
2764                                         $page_ns = $row->page_namespace;
2765                                         $page_title = $row->page_title;
2766                                         $sources[$page_id] = Title::makeTitle( $page_ns, $page_title );
2767                                         # Add groups needed for each restriction type if its not already there
2768                                         # Make sure this restriction type still exists
2769
2770                                         if ( !isset( $pagerestrictions[$row->pr_type] ) ) {
2771                                                 $pagerestrictions[$row->pr_type] = [];
2772                                         }
2773
2774                                         if (
2775                                                 isset( $pagerestrictions[$row->pr_type] )
2776                                                 && !in_array( $row->pr_level, $pagerestrictions[$row->pr_type] )
2777                                         ) {
2778                                                 $pagerestrictions[$row->pr_type][] = $row->pr_level;
2779                                         }
2780                                 } else {
2781                                         $sources = true;
2782                                 }
2783                         }
2784                 }
2785
2786                 if ( $getPages ) {
2787                         $this->mCascadeSources = $sources;
2788                         $this->mCascadingRestrictions = $pagerestrictions;
2789                 } else {
2790                         $this->mHasCascadingRestrictions = $sources;
2791                 }
2792
2793                 return [ $sources, $pagerestrictions ];
2794         }
2795
2796         /**
2797          * Accessor for mRestrictionsLoaded
2798          *
2799          * @return bool Whether or not the page's restrictions have already been
2800          * loaded from the database
2801          * @since 1.23
2802          */
2803         public function areRestrictionsLoaded() {
2804                 return $this->mRestrictionsLoaded;
2805         }
2806
2807         /**
2808          * Accessor/initialisation for mRestrictions
2809          *
2810          * @param string $action Action that permission needs to be checked for
2811          * @return array Restriction levels needed to take the action. All levels are
2812          *     required. Note that restriction levels are normally user rights, but 'sysop'
2813          *     and 'autoconfirmed' are also allowed for backwards compatibility. These should
2814          *     be mapped to 'editprotected' and 'editsemiprotected' respectively.
2815          */
2816         public function getRestrictions( $action ) {
2817                 if ( !$this->mRestrictionsLoaded ) {
2818                         $this->loadRestrictions();
2819                 }
2820                 return isset( $this->mRestrictions[$action] )
2821                                 ? $this->mRestrictions[$action]
2822                                 : [];
2823         }
2824
2825         /**
2826          * Accessor/initialisation for mRestrictions
2827          *
2828          * @return array Keys are actions, values are arrays as returned by
2829          *     Title::getRestrictions()
2830          * @since 1.23
2831          */
2832         public function getAllRestrictions() {
2833                 if ( !$this->mRestrictionsLoaded ) {
2834                         $this->loadRestrictions();
2835                 }
2836                 return $this->mRestrictions;
2837         }
2838
2839         /**
2840          * Get the expiry time for the restriction against a given action
2841          *
2842          * @param string $action
2843          * @return string|bool 14-char timestamp, or 'infinity' if the page is protected forever
2844          *     or not protected at all, or false if the action is not recognised.
2845          */
2846         public function getRestrictionExpiry( $action ) {
2847                 if ( !$this->mRestrictionsLoaded ) {
2848                         $this->loadRestrictions();
2849                 }
2850                 return isset( $this->mRestrictionsExpiry[$action] ) ? $this->mRestrictionsExpiry[$action] : false;
2851         }
2852
2853         /**
2854          * Returns cascading restrictions for the current article
2855          *
2856          * @return bool
2857          */
2858         function areRestrictionsCascading() {
2859                 if ( !$this->mRestrictionsLoaded ) {
2860                         $this->loadRestrictions();
2861                 }
2862
2863                 return $this->mCascadeRestriction;
2864         }
2865
2866         /**
2867          * Loads a string into mRestrictions array
2868          *
2869          * @param ResultWrapper $res Resource restrictions as an SQL result.
2870          * @param string $oldFashionedRestrictions Comma-separated list of page
2871          *        restrictions from page table (pre 1.10)
2872          */
2873         private function loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions = null ) {
2874                 $rows = [];
2875
2876                 foreach ( $res as $row ) {
2877                         $rows[] = $row;
2878                 }
2879
2880                 $this->loadRestrictionsFromRows( $rows, $oldFashionedRestrictions );
2881         }
2882
2883         /**
2884          * Compiles list of active page restrictions from both page table (pre 1.10)
2885          * and page_restrictions table for this existing page.
2886          * Public for usage by LiquidThreads.
2887          *
2888          * @param array $rows Array of db result objects
2889          * @param string $oldFashionedRestrictions Comma-separated list of page
2890          *   restrictions from page table (pre 1.10)
2891          */
2892         public function loadRestrictionsFromRows( $rows, $oldFashionedRestrictions = null ) {
2893                 $dbr = wfGetDB( DB_SLAVE );
2894
2895                 $restrictionTypes = $this->getRestrictionTypes();
2896
2897                 foreach ( $restrictionTypes as $type ) {
2898                         $this->mRestrictions[$type] = [];
2899                         $this->mRestrictionsExpiry[$type] = 'infinity';
2900                 }
2901
2902                 $this->mCascadeRestriction = false;
2903
2904                 # Backwards-compatibility: also load the restrictions from the page record (old format).
2905                 if ( $oldFashionedRestrictions !== null ) {
2906                         $this->mOldRestrictions = $oldFashionedRestrictions;
2907                 }
2908
2909                 if ( $this->mOldRestrictions === false ) {
2910                         $this->mOldRestrictions = $dbr->selectField( 'page', 'page_restrictions',
2911                                 [ 'page_id' => $this->getArticleID() ], __METHOD__ );
2912                 }
2913
2914                 if ( $this->mOldRestrictions != '' ) {
2915                         foreach ( explode( ':', trim( $this->mOldRestrictions ) ) as $restrict ) {
2916                                 $temp = explode( '=', trim( $restrict ) );
2917                                 if ( count( $temp ) == 1 ) {
2918                                         // old old format should be treated as edit/move restriction
2919                                         $this->mRestrictions['edit'] = explode( ',', trim( $temp[0] ) );
2920                                         $this->mRestrictions['move'] = explode( ',', trim( $temp[0] ) );
2921                                 } else {
2922                                         $restriction = trim( $temp[1] );
2923                                         if ( $restriction != '' ) { // some old entries are empty
2924                                                 $this->mRestrictions[$temp[0]] = explode( ',', $restriction );
2925                                         }
2926                                 }
2927                         }
2928                 }
2929
2930                 if ( count( $rows ) ) {
2931                         # Current system - load second to make them override.
2932                         $now = wfTimestampNow();
2933
2934                         # Cycle through all the restrictions.
2935                         foreach ( $rows as $row ) {
2936
2937                                 // Don't take care of restrictions types that aren't allowed
2938                                 if ( !in_array( $row->pr_type, $restrictionTypes ) ) {
2939                                         continue;
2940                                 }
2941
2942                                 // This code should be refactored, now that it's being used more generally,
2943                                 // But I don't really see any harm in leaving it in Block for now -werdna
2944                                 $expiry = $dbr->decodeExpiry( $row->pr_expiry );
2945
2946                                 // Only apply the restrictions if they haven't expired!
2947                                 if ( !$expiry || $expiry > $now ) {
2948                                         $this->mRestrictionsExpiry[$row->pr_type] = $expiry;
2949                                         $this->mRestrictions[$row->pr_type] = explode( ',', trim( $row->pr_level ) );
2950
2951                                         $this->mCascadeRestriction |= $row->pr_cascade;
2952                                 }
2953                         }
2954                 }
2955
2956                 $this->mRestrictionsLoaded = true;
2957         }
2958
2959         /**
2960          * Load restrictions from the page_restrictions table
2961          *
2962          * @param string $oldFashionedRestrictions Comma-separated list of page
2963          *   restrictions from page table (pre 1.10)
2964          */
2965         public function loadRestrictions( $oldFashionedRestrictions = null ) {
2966                 if ( !$this->mRestrictionsLoaded ) {
2967                         $dbr = wfGetDB( DB_SLAVE );
2968                         if ( $this->exists() ) {
2969                                 $res = $dbr->select(
2970                                         'page_restrictions',
2971                                         [ 'pr_type', 'pr_expiry', 'pr_level', 'pr_cascade' ],
2972                                         [ 'pr_page' => $this->getArticleID() ],
2973                                         __METHOD__
2974                                 );
2975
2976                                 $this->loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions );
2977                         } else {
2978                                 $title_protection = $this->getTitleProtection();
2979
2980                                 if ( $title_protection ) {
2981                                         $now = wfTimestampNow();
2982                                         $expiry = $dbr->decodeExpiry( $title_protection['expiry'] );
2983
2984                                         if ( !$expiry || $expiry > $now ) {
2985                                                 // Apply the restrictions
2986                                                 $this->mRestrictionsExpiry['create'] = $expiry;
2987                                                 $this->mRestrictions['create'] = explode( ',', trim( $title_protection['permission'] ) );
2988                                         } else { // Get rid of the old restrictions
2989                                                 $this->mTitleProtection = false;
2990                                         }
2991                                 } else {
2992                                         $this->mRestrictionsExpiry['create'] = 'infinity';
2993                                 }
2994                                 $this->mRestrictionsLoaded = true;
2995                         }
2996                 }
2997         }
2998
2999         /**
3000          * Flush the protection cache in this object and force reload from the database.
3001          * This is used when updating protection from WikiPage::doUpdateRestrictions().
3002          */
3003         public function flushRestrictions() {
3004                 $this->mRestrictionsLoaded = false;
3005                 $this->mTitleProtection = null;
3006         }
3007
3008         /**
3009          * Purge expired restrictions from the page_restrictions table
3010          */
3011         static function purgeExpiredRestrictions() {
3012                 if ( wfReadOnly() ) {
3013                         return;
3014                 }
3015
3016                 DeferredUpdates::addUpdate( new AtomicSectionUpdate(
3017                         wfGetDB( DB_MASTER ),
3018                         __METHOD__,
3019                         function ( IDatabase $dbw, $fname ) {
3020                                 $dbw->delete(
3021                                         'page_restrictions',
3022                                         [ 'pr_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ],
3023                                         $fname
3024                                 );
3025                                 $dbw->delete(
3026                                         'protected_titles',
3027                                         [ 'pt_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ],
3028                                         $fname
3029                                 );
3030                         }
3031                 ) );
3032         }
3033
3034         /**
3035          * Does this have subpages?  (Warning, usually requires an extra DB query.)
3036          *
3037          * @return bool
3038          */
3039         public function hasSubpages() {
3040                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
3041                         # Duh
3042                         return false;
3043                 }
3044
3045                 # We dynamically add a member variable for the purpose of this method
3046                 # alone to cache the result.  There's no point in having it hanging
3047                 # around uninitialized in every Title object; therefore we only add it
3048                 # if needed and don't declare it statically.
3049                 if ( $this->mHasSubpages === null ) {
3050                         $this->mHasSubpages = false;
3051                         $subpages = $this->getSubpages( 1 );
3052                         if ( $subpages instanceof TitleArray ) {
3053                                 $this->mHasSubpages = (bool)$subpages->count();
3054                         }
3055                 }
3056
3057                 return $this->mHasSubpages;
3058         }
3059
3060         /**
3061          * Get all subpages of this page.
3062          *
3063          * @param int $limit Maximum number of subpages to fetch; -1 for no limit
3064          * @return TitleArray|array TitleArray, or empty array if this page's namespace
3065          *  doesn't allow subpages
3066          */
3067         public function getSubpages( $limit = -1 ) {
3068                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3069                         return [];
3070                 }
3071
3072                 $dbr = wfGetDB( DB_SLAVE );
3073                 $conds['page_namespace'] = $this->getNamespace();
3074                 $conds[] = 'page_title ' . $dbr->buildLike( $this->getDBkey() . '/', $dbr->anyString() );
3075                 $options = [];
3076                 if ( $limit > -1 ) {
3077                         $options['LIMIT'] = $limit;
3078                 }
3079                 $this->mSubpages = TitleArray::newFromResult(
3080                         $dbr->select( 'page',
3081                                 [ 'page_id', 'page_namespace', 'page_title', 'page_is_redirect' ],
3082                                 $conds,
3083                                 __METHOD__,
3084                                 $options
3085                         )
3086                 );
3087                 return $this->mSubpages;
3088         }
3089
3090         /**
3091          * Is there a version of this page in the deletion archive?
3092          *
3093          * @return int The number of archived revisions
3094          */
3095         public function isDeleted() {
3096                 if ( $this->getNamespace() < 0 ) {
3097                         $n = 0;
3098                 } else {
3099                         $dbr = wfGetDB( DB_SLAVE );
3100
3101                         $n = $dbr->selectField( 'archive', 'COUNT(*)',
3102                                 [ 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ],
3103                                 __METHOD__
3104                         );
3105                         if ( $this->getNamespace() == NS_FILE ) {
3106                                 $n += $dbr->selectField( 'filearchive', 'COUNT(*)',
3107                                         [ 'fa_name' => $this->getDBkey() ],
3108                                         __METHOD__
3109                                 );
3110                         }
3111                 }
3112                 return (int)$n;
3113         }
3114
3115         /**
3116          * Is there a version of this page in the deletion archive?
3117          *
3118          * @return bool
3119          */
3120         public function isDeletedQuick() {
3121                 if ( $this->getNamespace() < 0 ) {
3122                         return false;
3123                 }
3124                 $dbr = wfGetDB( DB_SLAVE );
3125                 $deleted = (bool)$dbr->selectField( 'archive', '1',
3126                         [ 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ],
3127                         __METHOD__
3128                 );
3129                 if ( !$deleted && $this->getNamespace() == NS_FILE ) {
3130                         $deleted = (bool)$dbr->selectField( 'filearchive', '1',
3131                                 [ 'fa_name' => $this->getDBkey() ],
3132                                 __METHOD__
3133                         );
3134                 }
3135                 return $deleted;
3136         }
3137
3138         /**
3139          * Get the article ID for this Title from the link cache,
3140          * adding it if necessary
3141          *
3142          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select
3143          *  for update
3144          * @return int The ID
3145          */
3146         public function getArticleID( $flags = 0 ) {
3147                 if ( $this->getNamespace() < 0 ) {
3148                         $this->mArticleID = 0;
3149                         return $this->mArticleID;
3150                 }
3151                 $linkCache = LinkCache::singleton();
3152                 if ( $flags & self::GAID_FOR_UPDATE ) {
3153                         $oldUpdate = $linkCache->forUpdate( true );
3154                         $linkCache->clearLink( $this );
3155                         $this->mArticleID = $linkCache->addLinkObj( $this );
3156                         $linkCache->forUpdate( $oldUpdate );
3157                 } else {
3158                         if ( -1 == $this->mArticleID ) {
3159                                 $this->mArticleID = $linkCache->addLinkObj( $this );
3160                         }
3161                 }
3162                 return $this->mArticleID;
3163         }
3164
3165         /**
3166          * Is this an article that is a redirect page?
3167          * Uses link cache, adding it if necessary
3168          *
3169          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3170          * @return bool
3171          */
3172         public function isRedirect( $flags = 0 ) {
3173                 if ( !is_null( $this->mRedirect ) ) {
3174                         return $this->mRedirect;
3175                 }
3176                 if ( !$this->getArticleID( $flags ) ) {
3177                         $this->mRedirect = false;
3178                         return $this->mRedirect;
3179                 }
3180
3181                 $linkCache = LinkCache::singleton();
3182                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3183                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'redirect' );
3184                 if ( $cached === null ) {
3185                         # Trust LinkCache's state over our own
3186                         # LinkCache is telling us that the page doesn't exist, despite there being cached
3187                         # data relating to an existing page in $this->mArticleID. Updaters should clear
3188                         # LinkCache as appropriate, or use $flags = Title::GAID_FOR_UPDATE. If that flag is
3189                         # set, then LinkCache will definitely be up to date here, since getArticleID() forces
3190                         # LinkCache to refresh its data from the master.
3191                         $this->mRedirect = false;
3192                         return $this->mRedirect;
3193                 }
3194
3195                 $this->mRedirect = (bool)$cached;
3196
3197                 return $this->mRedirect;
3198         }
3199
3200         /**
3201          * What is the length of this page?
3202          * Uses link cache, adding it if necessary
3203          *
3204          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3205          * @return int
3206          */
3207         public function getLength( $flags = 0 ) {
3208                 if ( $this->mLength != -1 ) {
3209                         return $this->mLength;
3210                 }
3211                 if ( !$this->getArticleID( $flags ) ) {
3212                         $this->mLength = 0;
3213                         return $this->mLength;
3214                 }
3215                 $linkCache = LinkCache::singleton();
3216                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3217                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'length' );
3218                 if ( $cached === null ) {
3219                         # Trust LinkCache's state over our own, as for isRedirect()
3220                         $this->mLength = 0;
3221                         return $this->mLength;
3222                 }
3223
3224                 $this->mLength = intval( $cached );
3225
3226                 return $this->mLength;
3227         }
3228
3229         /**
3230          * What is the page_latest field for this page?
3231          *
3232          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3233          * @return int Int or 0 if the page doesn't exist
3234          */
3235         public function getLatestRevID( $flags = 0 ) {
3236                 if ( !( $flags & Title::GAID_FOR_UPDATE ) && $this->mLatestID !== false ) {
3237                         return intval( $this->mLatestID );
3238                 }
3239                 if ( !$this->getArticleID( $flags ) ) {
3240                         $this->mLatestID = 0;
3241                         return $this->mLatestID;
3242                 }
3243                 $linkCache = LinkCache::singleton();
3244                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3245                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'revision' );
3246                 if ( $cached === null ) {
3247                         # Trust LinkCache's state over our own, as for isRedirect()
3248                         $this->mLatestID = 0;
3249                         return $this->mLatestID;
3250                 }
3251
3252                 $this->mLatestID = intval( $cached );
3253
3254                 return $this->mLatestID;
3255         }
3256
3257         /**
3258          * This clears some fields in this object, and clears any associated
3259          * keys in the "bad links" section of the link cache.
3260          *
3261          * - This is called from WikiPage::doEdit() and WikiPage::insertOn() to allow
3262          * loading of the new page_id. It's also called from
3263          * WikiPage::doDeleteArticleReal()
3264          *
3265          * @param int $newid The new Article ID
3266          */
3267         public function resetArticleID( $newid ) {
3268                 $linkCache = LinkCache::singleton();
3269                 $linkCache->clearLink( $this );
3270
3271                 if ( $newid === false ) {
3272                         $this->mArticleID = -1;
3273                 } else {
3274                         $this->mArticleID = intval( $newid );
3275                 }
3276                 $this->mRestrictionsLoaded = false;
3277                 $this->mRestrictions = [];
3278                 $this->mOldRestrictions = false;
3279                 $this->mRedirect = null;
3280                 $this->mLength = -1;
3281                 $this->mLatestID = false;
3282                 $this->mContentModel = false;
3283                 $this->mEstimateRevisions = null;
3284                 $this->mPageLanguage = false;
3285                 $this->mDbPageLanguage = false;
3286                 $this->mIsBigDeletion = null;
3287         }
3288
3289         public static function clearCaches() {
3290                 $linkCache = LinkCache::singleton();
3291                 $linkCache->clear();
3292
3293                 $titleCache = self::getTitleCache();
3294                 $titleCache->clear();
3295         }
3296
3297         /**
3298          * Capitalize a text string for a title if it belongs to a namespace that capitalizes
3299          *
3300          * @param string $text Containing title to capitalize
3301          * @param int $ns Namespace index, defaults to NS_MAIN
3302          * @return string Containing capitalized title
3303          */
3304         public static function capitalize( $text, $ns = NS_MAIN ) {
3305                 global $wgContLang;
3306
3307                 if ( MWNamespace::isCapitalized( $ns ) ) {
3308                         return $wgContLang->ucfirst( $text );
3309                 } else {
3310                         return $text;
3311                 }
3312         }
3313
3314         /**
3315          * Secure and split - main initialisation function for this object
3316          *
3317          * Assumes that mDbkeyform has been set, and is urldecoded
3318          * and uses underscores, but not otherwise munged.  This function
3319          * removes illegal characters, splits off the interwiki and
3320          * namespace prefixes, sets the other forms, and canonicalizes
3321          * everything.
3322          *
3323          * @throws MalformedTitleException On invalid titles
3324          * @return bool True on success
3325          */
3326         private function secureAndSplit() {
3327                 # Initialisation
3328                 $this->mInterwiki = '';
3329                 $this->mFragment = '';
3330                 $this->mNamespace = $this->mDefaultNamespace; # Usually NS_MAIN
3331
3332                 $dbkey = $this->mDbkeyform;
3333
3334                 // @note: splitTitleString() is a temporary hack to allow MediaWikiTitleCodec to share
3335                 //        the parsing code with Title, while avoiding massive refactoring.
3336                 // @todo: get rid of secureAndSplit, refactor parsing code.
3337                 $titleParser = self::getMediaWikiTitleCodec();
3338                 // MalformedTitleException can be thrown here
3339                 $parts = $titleParser->splitTitleString( $dbkey, $this->getDefaultNamespace() );
3340
3341                 # Fill fields
3342                 $this->setFragment( '#' . $parts['fragment'] );
3343                 $this->mInterwiki = $parts['interwiki'];
3344                 $this->mLocalInterwiki = $parts['local_interwiki'];
3345                 $this->mNamespace = $parts['namespace'];
3346                 $this->mUserCaseDBKey = $parts['user_case_dbkey'];
3347
3348                 $this->mDbkeyform = $parts['dbkey'];
3349                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
3350                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
3351
3352                 # We already know that some pages won't be in the database!
3353                 if ( $this->isExternal() || $this->mNamespace == NS_SPECIAL ) {
3354                         $this->mArticleID = 0;
3355                 }
3356
3357                 return true;
3358         }
3359
3360         /**
3361          * Get an array of Title objects linking to this Title
3362          * Also stores the IDs in the link cache.
3363          *
3364          * WARNING: do not use this function on arbitrary user-supplied titles!
3365          * On heavily-used templates it will max out the memory.
3366          *
3367          * @param array $options May be FOR UPDATE
3368          * @param string $table Table name
3369          * @param string $prefix Fields prefix
3370          * @return Title[] Array of Title objects linking here
3371          */
3372         public function getLinksTo( $options = [], $table = 'pagelinks', $prefix = 'pl' ) {
3373                 if ( count( $options ) > 0 ) {
3374                         $db = wfGetDB( DB_MASTER );
3375                 } else {
3376                         $db = wfGetDB( DB_SLAVE );
3377                 }
3378
3379                 $res = $db->select(
3380                         [ 'page', $table ],
3381                         self::getSelectFields(),
3382                         [
3383                                 "{$prefix}_from=page_id",
3384                                 "{$prefix}_namespace" => $this->getNamespace(),
3385                                 "{$prefix}_title" => $this->getDBkey() ],
3386                         __METHOD__,
3387                         $options
3388                 );
3389
3390                 $retVal = [];
3391                 if ( $res->numRows() ) {
3392                         $linkCache = LinkCache::singleton();
3393                         foreach ( $res as $row ) {
3394                                 $titleObj = Title::makeTitle( $row->page_namespace, $row->page_title );
3395                                 if ( $titleObj ) {
3396                                         $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3397                                         $retVal[] = $titleObj;
3398                                 }
3399                         }
3400                 }
3401                 return $retVal;
3402         }
3403
3404         /**
3405          * Get an array of Title objects using this Title as a template
3406          * Also stores the IDs in the link cache.
3407          *
3408          * WARNING: do not use this function on arbitrary user-supplied titles!
3409          * On heavily-used templates it will max out the memory.
3410          *
3411          * @param array $options Query option to Database::select()
3412          * @return Title[] Array of Title the Title objects linking here
3413          */
3414         public function getTemplateLinksTo( $options = [] ) {
3415                 return $this->getLinksTo( $options, 'templatelinks', 'tl' );
3416         }
3417
3418         /**
3419          * Get an array of Title objects linked from this Title
3420          * Also stores the IDs in the link cache.
3421          *
3422          * WARNING: do not use this function on arbitrary user-supplied titles!
3423          * On heavily-used templates it will max out the memory.
3424          *
3425          * @param array $options Query option to Database::select()
3426          * @param string $table Table name
3427          * @param string $prefix Fields prefix
3428          * @return array Array of Title objects linking here
3429          */
3430         public function getLinksFrom( $options = [], $table = 'pagelinks', $prefix = 'pl' ) {
3431                 $id = $this->getArticleID();
3432
3433                 # If the page doesn't exist; there can't be any link from this page
3434                 if ( !$id ) {
3435                         return [];
3436                 }
3437
3438                 $db = wfGetDB( DB_SLAVE );
3439
3440                 $blNamespace = "{$prefix}_namespace";
3441                 $blTitle = "{$prefix}_title";
3442
3443                 $res = $db->select(
3444                         [ $table, 'page' ],
3445                         array_merge(
3446                                 [ $blNamespace, $blTitle ],
3447                                 WikiPage::selectFields()
3448                         ),
3449                         [ "{$prefix}_from" => $id ],
3450                         __METHOD__,
3451                         $options,
3452                         [ 'page' => [
3453                                 'LEFT JOIN',
3454                                 [ "page_namespace=$blNamespace", "page_title=$blTitle" ]
3455                         ] ]
3456                 );
3457
3458                 $retVal = [];
3459                 $linkCache = LinkCache::singleton();
3460                 foreach ( $res as $row ) {
3461                         if ( $row->page_id ) {
3462                                 $titleObj = Title::newFromRow( $row );
3463                         } else {
3464                                 $titleObj = Title::makeTitle( $row->$blNamespace, $row->$blTitle );
3465                                 $linkCache->addBadLinkObj( $titleObj );
3466                         }
3467                         $retVal[] = $titleObj;
3468                 }
3469
3470                 return $retVal;
3471         }
3472
3473         /**
3474          * Get an array of Title objects used on this Title as a template
3475          * Also stores the IDs in the link cache.
3476          *
3477          * WARNING: do not use this function on arbitrary user-supplied titles!
3478          * On heavily-used templates it will max out the memory.
3479          *
3480          * @param array $options May be FOR UPDATE
3481          * @return Title[] Array of Title the Title objects used here
3482          */
3483         public function getTemplateLinksFrom( $options = [] ) {
3484                 return $this->getLinksFrom( $options, 'templatelinks', 'tl' );
3485         }
3486
3487         /**
3488          * Get an array of Title objects referring to non-existent articles linked
3489          * from this page.
3490          *
3491          * @todo check if needed (used only in SpecialBrokenRedirects.php, and
3492          *   should use redirect table in this case).
3493          * @return Title[] Array of Title the Title objects
3494          */
3495         public function getBrokenLinksFrom() {
3496                 if ( $this->getArticleID() == 0 ) {
3497                         # All links from article ID 0 are false positives
3498                         return [];
3499                 }
3500
3501                 $dbr = wfGetDB( DB_SLAVE );
3502                 $res = $dbr->select(
3503                         [ 'page', 'pagelinks' ],
3504                         [ 'pl_namespace', 'pl_title' ],
3505                         [
3506                                 'pl_from' => $this->getArticleID(),
3507                                 'page_namespace IS NULL'
3508                         ],
3509                         __METHOD__, [],
3510                         [
3511                                 'page' => [
3512                                         'LEFT JOIN',
3513                                         [ 'pl_namespace=page_namespace', 'pl_title=page_title' ]
3514                                 ]
3515                         ]
3516                 );
3517
3518                 $retVal = [];
3519                 foreach ( $res as $row ) {
3520                         $retVal[] = Title::makeTitle( $row->pl_namespace, $row->pl_title );
3521                 }
3522                 return $retVal;
3523         }
3524
3525         /**
3526          * Get a list of URLs to purge from the CDN cache when this
3527          * page changes
3528          *
3529          * @return string[] Array of String the URLs
3530          */
3531         public function getCdnUrls() {
3532                 $urls = [
3533                         $this->getInternalURL(),
3534                         $this->getInternalURL( 'action=history' )
3535                 ];
3536
3537                 $pageLang = $this->getPageLanguage();
3538                 if ( $pageLang->hasVariants() ) {
3539                         $variants = $pageLang->getVariants();
3540                         foreach ( $variants as $vCode ) {
3541                                 $urls[] = $this->getInternalURL( $vCode );
3542                         }
3543                 }
3544
3545                 // If we are looking at a css/js user subpage, purge the action=raw.
3546                 if ( $this->isJsSubpage() ) {
3547                         $urls[] = $this->getInternalURL( 'action=raw&ctype=text/javascript' );
3548                 } elseif ( $this->isCssSubpage() ) {
3549                         $urls[] = $this->getInternalURL( 'action=raw&ctype=text/css' );
3550                 }
3551
3552                 Hooks::run( 'TitleSquidURLs', [ $this, &$urls ] );
3553                 return $urls;
3554         }
3555
3556         /**
3557          * @deprecated since 1.27 use getCdnUrls()
3558          */
3559         public function getSquidURLs() {
3560                 return $this->getCdnUrls();
3561         }
3562
3563         /**
3564          * Purge all applicable CDN URLs
3565          */
3566         public function purgeSquid() {
3567                 DeferredUpdates::addUpdate(
3568                         new CdnCacheUpdate( $this->getCdnUrls() ),
3569                         DeferredUpdates::PRESEND
3570                 );
3571         }
3572
3573         /**
3574          * Move this page without authentication
3575          *
3576          * @deprecated since 1.25 use MovePage class instead
3577          * @param Title $nt The new page Title
3578          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3579          */
3580         public function moveNoAuth( &$nt ) {
3581                 wfDeprecated( __METHOD__, '1.25' );
3582                 return $this->moveTo( $nt, false );
3583         }
3584
3585         /**
3586          * Check whether a given move operation would be valid.
3587          * Returns true if ok, or a getUserPermissionsErrors()-like array otherwise
3588          *
3589          * @deprecated since 1.25, use MovePage's methods instead
3590          * @param Title $nt The new title
3591          * @param bool $auth Whether to check user permissions (uses $wgUser)
3592          * @param string $reason Is the log summary of the move, used for spam checking
3593          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3594          */
3595         public function isValidMoveOperation( &$nt, $auth = true, $reason = '' ) {
3596                 global $wgUser;
3597
3598                 if ( !( $nt instanceof Title ) ) {
3599                         // Normally we'd add this to $errors, but we'll get
3600                         // lots of syntax errors if $nt is not an object
3601                         return [ [ 'badtitletext' ] ];
3602                 }
3603
3604                 $mp = new MovePage( $this, $nt );
3605                 $errors = $mp->isValidMove()->getErrorsArray();
3606                 if ( $auth ) {
3607                         $errors = wfMergeErrorArrays(
3608                                 $errors,
3609                                 $mp->checkPermissions( $wgUser, $reason )->getErrorsArray()
3610                         );
3611                 }
3612
3613                 return $errors ?: true;
3614         }
3615
3616         /**
3617          * Check if the requested move target is a valid file move target
3618          * @todo move this to MovePage
3619          * @param Title $nt Target title
3620          * @return array List of errors
3621          */
3622         protected function validateFileMoveOperation( $nt ) {
3623                 global $wgUser;
3624
3625                 $errors = [];
3626
3627                 $destFile = wfLocalFile( $nt );
3628                 $destFile->load( File::READ_LATEST );
3629                 if ( !$wgUser->isAllowed( 'reupload-shared' )
3630                         && !$destFile->exists() && wfFindFile( $nt )
3631                 ) {
3632                         $errors[] = [ 'file-exists-sharedrepo' ];
3633                 }
3634
3635                 return $errors;
3636         }
3637
3638         /**
3639          * Move a title to a new location
3640          *
3641          * @deprecated since 1.25, use the MovePage class instead
3642          * @param Title $nt The new title
3643          * @param bool $auth Indicates whether $wgUser's permissions
3644          *  should be checked
3645          * @param string $reason The reason for the move
3646          * @param bool $createRedirect Whether to create a redirect from the old title to the new title.
3647          *  Ignored if the user doesn't have the suppressredirect right.
3648          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3649          */
3650         public function moveTo( &$nt, $auth = true, $reason = '', $createRedirect = true ) {
3651                 global $wgUser;
3652                 $err = $this->isValidMoveOperation( $nt, $auth, $reason );
3653                 if ( is_array( $err ) ) {
3654                         // Auto-block user's IP if the account was "hard" blocked
3655                         $wgUser->spreadAnyEditBlock();
3656                         return $err;
3657                 }
3658                 // Check suppressredirect permission
3659                 if ( $auth && !$wgUser->isAllowed( 'suppressredirect' ) ) {
3660                         $createRedirect = true;
3661                 }
3662
3663                 $mp = new MovePage( $this, $nt );
3664                 $status = $mp->move( $wgUser, $reason, $createRedirect );
3665                 if ( $status->isOK() ) {
3666                         return true;
3667                 } else {
3668                         return $status->getErrorsArray();
3669                 }
3670         }
3671
3672         /**
3673          * Move this page's subpages to be subpages of $nt
3674          *
3675          * @param Title $nt Move target
3676          * @param bool $auth Whether $wgUser's permissions should be checked
3677          * @param string $reason The reason for the move
3678          * @param bool $createRedirect Whether to create redirects from the old subpages to
3679          *     the new ones Ignored if the user doesn't have the 'suppressredirect' right
3680          * @return array Array with old page titles as keys, and strings (new page titles) or
3681          *     arrays (errors) as values, or an error array with numeric indices if no pages
3682          *     were moved
3683          */
3684         public function moveSubpages( $nt, $auth = true, $reason = '', $createRedirect = true ) {
3685                 global $wgMaximumMovedPages;
3686                 // Check permissions
3687                 if ( !$this->userCan( 'move-subpages' ) ) {
3688                         return [ 'cant-move-subpages' ];
3689                 }
3690                 // Do the source and target namespaces support subpages?
3691                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3692                         return [ 'namespace-nosubpages',
3693                                 MWNamespace::getCanonicalName( $this->getNamespace() ) ];
3694                 }
3695                 if ( !MWNamespace::hasSubpages( $nt->getNamespace() ) ) {
3696                         return [ 'namespace-nosubpages',
3697                                 MWNamespace::getCanonicalName( $nt->getNamespace() ) ];
3698                 }
3699
3700                 $subpages = $this->getSubpages( $wgMaximumMovedPages + 1 );
3701                 $retval = [];
3702                 $count = 0;
3703                 foreach ( $subpages as $oldSubpage ) {
3704                         $count++;
3705                         if ( $count > $wgMaximumMovedPages ) {
3706                                 $retval[$oldSubpage->getPrefixedText()] =
3707                                                 [ 'movepage-max-pages',
3708                                                         $wgMaximumMovedPages ];
3709                                 break;
3710                         }
3711
3712                         // We don't know whether this function was called before
3713                         // or after moving the root page, so check both
3714                         // $this and $nt
3715                         if ( $oldSubpage->getArticleID() == $this->getArticleID()
3716                                 || $oldSubpage->getArticleID() == $nt->getArticleID()
3717                         ) {
3718                                 // When moving a page to a subpage of itself,
3719                                 // don't move it twice
3720                                 continue;
3721                         }
3722                         $newPageName = preg_replace(
3723                                         '#^' . preg_quote( $this->getDBkey(), '#' ) . '#',
3724                                         StringUtils::escapeRegexReplacement( $nt->getDBkey() ), # bug 21234
3725                                         $oldSubpage->getDBkey() );
3726                         if ( $oldSubpage->isTalkPage() ) {
3727                                 $newNs = $nt->getTalkPage()->getNamespace();
3728                         } else {
3729                                 $newNs = $nt->getSubjectPage()->getNamespace();
3730                         }
3731                         # Bug 14385: we need makeTitleSafe because the new page names may
3732                         # be longer than 255 characters.
3733                         $newSubpage = Title::makeTitleSafe( $newNs, $newPageName );
3734
3735                         $success = $oldSubpage->moveTo( $newSubpage, $auth, $reason, $createRedirect );
3736                         if ( $success === true ) {
3737                                 $retval[$oldSubpage->getPrefixedText()] = $newSubpage->getPrefixedText();
3738                         } else {
3739                                 $retval[$oldSubpage->getPrefixedText()] = $success;
3740                         }
3741                 }
3742                 return $retval;
3743         }
3744
3745         /**
3746          * Checks if this page is just a one-rev redirect.
3747          * Adds lock, so don't use just for light purposes.
3748          *
3749          * @return bool
3750          */
3751         public function isSingleRevRedirect() {
3752                 global $wgContentHandlerUseDB;
3753
3754                 $dbw = wfGetDB( DB_MASTER );
3755
3756                 # Is it a redirect?
3757                 $fields = [ 'page_is_redirect', 'page_latest', 'page_id' ];
3758                 if ( $wgContentHandlerUseDB ) {
3759                         $fields[] = 'page_content_model';
3760                 }
3761
3762                 $row = $dbw->selectRow( 'page',
3763                         $fields,
3764                         $this->pageCond(),
3765                         __METHOD__,
3766                         [ 'FOR UPDATE' ]
3767                 );
3768                 # Cache some fields we may want
3769                 $this->mArticleID = $row ? intval( $row->page_id ) : 0;
3770                 $this->mRedirect = $row ? (bool)$row->page_is_redirect : false;
3771                 $this->mLatestID = $row ? intval( $row->page_latest ) : false;
3772                 $this->mContentModel = $row && isset( $row->page_content_model )
3773                         ? strval( $row->page_content_model )
3774                         : false;
3775
3776                 if ( !$this->mRedirect ) {
3777                         return false;
3778                 }
3779                 # Does the article have a history?
3780                 $row = $dbw->selectField( [ 'page', 'revision' ],
3781                         'rev_id',
3782                         [ 'page_namespace' => $this->getNamespace(),
3783                                 'page_title' => $this->getDBkey(),
3784                                 'page_id=rev_page',
3785                                 'page_latest != rev_id'
3786                         ],
3787                         __METHOD__,
3788                         [ 'FOR UPDATE' ]
3789                 );
3790                 # Return true if there was no history
3791                 return ( $row === false );
3792         }
3793
3794         /**
3795          * Checks if $this can be moved to a given Title
3796          * - Selects for update, so don't call it unless you mean business
3797          *
3798          * @deprecated since 1.25, use MovePage's methods instead
3799          * @param Title $nt The new title to check
3800          * @return bool
3801          */
3802         public function isValidMoveTarget( $nt ) {
3803                 # Is it an existing file?
3804                 if ( $nt->getNamespace() == NS_FILE ) {
3805                         $file = wfLocalFile( $nt );
3806                         $file->load( File::READ_LATEST );
3807                         if ( $file->exists() ) {
3808                                 wfDebug( __METHOD__ . ": file exists\n" );
3809                                 return false;
3810                         }
3811                 }
3812                 # Is it a redirect with no history?
3813                 if ( !$nt->isSingleRevRedirect() ) {
3814                         wfDebug( __METHOD__ . ": not a one-rev redirect\n" );
3815                         return false;
3816                 }
3817                 # Get the article text
3818                 $rev = Revision::newFromTitle( $nt, false, Revision::READ_LATEST );
3819                 if ( !is_object( $rev ) ) {
3820                         return false;
3821                 }
3822                 $content = $rev->getContent();
3823                 # Does the redirect point to the source?
3824                 # Or is it a broken self-redirect, usually caused by namespace collisions?
3825                 $redirTitle = $content ? $content->getRedirectTarget() : null;
3826
3827                 if ( $redirTitle ) {
3828                         if ( $redirTitle->getPrefixedDBkey() != $this->getPrefixedDBkey() &&
3829                                 $redirTitle->getPrefixedDBkey() != $nt->getPrefixedDBkey() ) {
3830                                 wfDebug( __METHOD__ . ": redirect points to other page\n" );
3831                                 return false;
3832                         } else {
3833                                 return true;
3834                         }
3835                 } else {
3836                         # Fail safe (not a redirect after all. strange.)
3837                         wfDebug( __METHOD__ . ": failsafe: database sais " . $nt->getPrefixedDBkey() .
3838                                                 " is a redirect, but it doesn't contain a valid redirect.\n" );
3839                         return false;
3840                 }
3841         }
3842
3843         /**
3844          * Get categories to which this Title belongs and return an array of
3845          * categories' names.
3846          *
3847          * @return array Array of parents in the form:
3848          *        $parent => $currentarticle
3849          */
3850         public function getParentCategories() {
3851                 global $wgContLang;
3852
3853                 $data = [];
3854
3855                 $titleKey = $this->getArticleID();
3856
3857                 if ( $titleKey === 0 ) {
3858                         return $data;
3859                 }
3860
3861                 $dbr = wfGetDB( DB_SLAVE );
3862
3863                 $res = $dbr->select(
3864                         'categorylinks',
3865                         'cl_to',
3866                         [ 'cl_from' => $titleKey ],
3867                         __METHOD__
3868                 );
3869
3870                 if ( $res->numRows() > 0 ) {
3871                         foreach ( $res as $row ) {
3872                                 // $data[] = Title::newFromText($wgContLang->getNsText ( NS_CATEGORY ).':'.$row->cl_to);
3873                                 $data[$wgContLang->getNsText( NS_CATEGORY ) . ':' . $row->cl_to] = $this->getFullText();
3874                         }
3875                 }
3876                 return $data;
3877         }
3878
3879         /**
3880          * Get a tree of parent categories
3881          *
3882          * @param array $children Array with the children in the keys, to check for circular refs
3883          * @return array Tree of parent categories
3884          */
3885         public function getParentCategoryTree( $children = [] ) {
3886                 $stack = [];
3887                 $parents = $this->getParentCategories();
3888
3889                 if ( $parents ) {
3890                         foreach ( $parents as $parent => $current ) {
3891                                 if ( array_key_exists( $parent, $children ) ) {
3892                                         # Circular reference
3893                                         $stack[$parent] = [];
3894                                 } else {
3895                                         $nt = Title::newFromText( $parent );
3896                                         if ( $nt ) {
3897                                                 $stack[$parent] = $nt->getParentCategoryTree( $children + [ $parent => 1 ] );
3898                                         }
3899                                 }
3900                         }
3901                 }
3902
3903                 return $stack;
3904         }
3905
3906         /**
3907          * Get an associative array for selecting this title from
3908          * the "page" table
3909          *
3910          * @return array Array suitable for the $where parameter of DB::select()
3911          */
3912         public function pageCond() {
3913                 if ( $this->mArticleID > 0 ) {
3914                         // PK avoids secondary lookups in InnoDB, shouldn't hurt other DBs
3915                         return [ 'page_id' => $this->mArticleID ];
3916                 } else {
3917                         return [ 'page_namespace' => $this->mNamespace, 'page_title' => $this->mDbkeyform ];
3918                 }
3919         }
3920
3921         /**
3922          * Get the revision ID of the previous revision
3923          *
3924          * @param int $revId Revision ID. Get the revision that was before this one.
3925          * @param int $flags Title::GAID_FOR_UPDATE
3926          * @return int|bool Old revision ID, or false if none exists
3927          */
3928         public function getPreviousRevisionID( $revId, $flags = 0 ) {
3929                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
3930                 $revId = $db->selectField( 'revision', 'rev_id',
3931                         [
3932                                 'rev_page' => $this->getArticleID( $flags ),
3933                                 'rev_id < ' . intval( $revId )
3934                         ],
3935                         __METHOD__,
3936                         [ 'ORDER BY' => 'rev_id DESC' ]
3937                 );
3938
3939                 if ( $revId === false ) {
3940                         return false;
3941                 } else {
3942                         return intval( $revId );
3943                 }
3944         }
3945
3946         /**
3947          * Get the revision ID of the next revision
3948          *
3949          * @param int $revId Revision ID. Get the revision that was after this one.
3950          * @param int $flags Title::GAID_FOR_UPDATE
3951          * @return int|bool Next revision ID, or false if none exists
3952          */
3953         public function getNextRevisionID( $revId, $flags = 0 ) {
3954                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
3955                 $revId = $db->selectField( 'revision', 'rev_id',
3956                         [
3957                                 'rev_page' => $this->getArticleID( $flags ),
3958                                 'rev_id > ' . intval( $revId )
3959                         ],
3960                         __METHOD__,
3961                         [ 'ORDER BY' => 'rev_id' ]
3962                 );
3963
3964                 if ( $revId === false ) {
3965                         return false;
3966                 } else {
3967                         return intval( $revId );
3968                 }
3969         }
3970
3971         /**
3972          * Get the first revision of the page
3973          *
3974          * @param int $flags Title::GAID_FOR_UPDATE
3975          * @return Revision|null If page doesn't exist
3976          */
3977         public function getFirstRevision( $flags = 0 ) {
3978                 $pageId = $this->getArticleID( $flags );
3979                 if ( $pageId ) {
3980                         $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
3981                         $row = $db->selectRow( 'revision', Revision::selectFields(),
3982                                 [ 'rev_page' => $pageId ],
3983                                 __METHOD__,
3984                                 [ 'ORDER BY' => 'rev_timestamp ASC', 'LIMIT' => 1 ]
3985                         );
3986                         if ( $row ) {
3987                                 return new Revision( $row );
3988                         }
3989                 }
3990                 return null;
3991         }
3992
3993         /**
3994          * Get the oldest revision timestamp of this page
3995          *
3996          * @param int $flags Title::GAID_FOR_UPDATE
3997          * @return string MW timestamp
3998          */
3999         public function getEarliestRevTime( $flags = 0 ) {
4000                 $rev = $this->getFirstRevision( $flags );
4001                 return $rev ? $rev->getTimestamp() : null;
4002         }
4003
4004         /**
4005          * Check if this is a new page
4006          *
4007          * @return bool
4008          */
4009         public function isNewPage() {
4010                 $dbr = wfGetDB( DB_SLAVE );
4011                 return (bool)$dbr->selectField( 'page', 'page_is_new', $this->pageCond(), __METHOD__ );
4012         }
4013
4014         /**
4015          * Check whether the number of revisions of this page surpasses $wgDeleteRevisionsLimit
4016          *
4017          * @return bool
4018          */
4019         public function isBigDeletion() {
4020                 global $wgDeleteRevisionsLimit;
4021
4022                 if ( !$wgDeleteRevisionsLimit ) {
4023                         return false;
4024                 }
4025
4026                 if ( $this->mIsBigDeletion === null ) {
4027                         $dbr = wfGetDB( DB_SLAVE );
4028
4029                         $revCount = $dbr->selectRowCount(
4030                                 'revision',
4031                                 '1',
4032                                 [ 'rev_page' => $this->getArticleID() ],
4033                                 __METHOD__,
4034                                 [ 'LIMIT' => $wgDeleteRevisionsLimit + 1 ]
4035                         );
4036
4037                         $this->mIsBigDeletion = $revCount > $wgDeleteRevisionsLimit;
4038                 }
4039
4040                 return $this->mIsBigDeletion;
4041         }
4042
4043         /**
4044          * Get the approximate revision count of this page.
4045          *
4046          * @return int
4047          */
4048         public function estimateRevisionCount() {
4049                 if ( !$this->exists() ) {
4050                         return 0;
4051                 }
4052
4053                 if ( $this->mEstimateRevisions === null ) {
4054                         $dbr = wfGetDB( DB_SLAVE );
4055                         $this->mEstimateRevisions = $dbr->estimateRowCount( 'revision', '*',
4056                                 [ 'rev_page' => $this->getArticleID() ], __METHOD__ );
4057                 }
4058
4059                 return $this->mEstimateRevisions;
4060         }
4061
4062         /**
4063          * Get the number of revisions between the given revision.
4064          * Used for diffs and other things that really need it.
4065          *
4066          * @param int|Revision $old Old revision or rev ID (first before range)
4067          * @param int|Revision $new New revision or rev ID (first after range)
4068          * @param int|null $max Limit of Revisions to count, will be incremented to detect truncations
4069          * @return int Number of revisions between these revisions.
4070          */
4071         public function countRevisionsBetween( $old, $new, $max = null ) {
4072                 if ( !( $old instanceof Revision ) ) {
4073                         $old = Revision::newFromTitle( $this, (int)$old );
4074                 }
4075                 if ( !( $new instanceof Revision ) ) {
4076                         $new = Revision::newFromTitle( $this, (int)$new );
4077                 }
4078                 if ( !$old || !$new ) {
4079                         return 0; // nothing to compare
4080                 }
4081                 $dbr = wfGetDB( DB_SLAVE );
4082                 $conds = [
4083                         'rev_page' => $this->getArticleID(),
4084                         'rev_timestamp > ' . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4085                         'rev_timestamp < ' . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4086                 ];
4087                 if ( $max !== null ) {
4088                         return $dbr->selectRowCount( 'revision', '1',
4089                                 $conds,
4090                                 __METHOD__,
4091                                 [ 'LIMIT' => $max + 1 ] // extra to detect truncation
4092                         );
4093                 } else {
4094                         return (int)$dbr->selectField( 'revision', 'count(*)', $conds, __METHOD__ );
4095                 }
4096         }
4097
4098         /**
4099          * Get the authors between the given revisions or revision IDs.
4100          * Used for diffs and other things that really need it.
4101          *
4102          * @since 1.23
4103          *
4104          * @param int|Revision $old Old revision or rev ID (first before range by default)
4105          * @param int|Revision $new New revision or rev ID (first after range by default)
4106          * @param int $limit Maximum number of authors
4107          * @param string|array $options (Optional): Single option, or an array of options:
4108          *     'include_old' Include $old in the range; $new is excluded.
4109          *     'include_new' Include $new in the range; $old is excluded.
4110          *     'include_both' Include both $old and $new in the range.
4111          *     Unknown option values are ignored.
4112          * @return array|null Names of revision authors in the range; null if not both revisions exist
4113          */
4114         public function getAuthorsBetween( $old, $new, $limit, $options = [] ) {
4115                 if ( !( $old instanceof Revision ) ) {
4116                         $old = Revision::newFromTitle( $this, (int)$old );
4117                 }
4118                 if ( !( $new instanceof Revision ) ) {
4119                         $new = Revision::newFromTitle( $this, (int)$new );
4120                 }
4121                 // XXX: what if Revision objects are passed in, but they don't refer to this title?
4122                 // Add $old->getPage() != $new->getPage() || $old->getPage() != $this->getArticleID()
4123                 // in the sanity check below?
4124                 if ( !$old || !$new ) {
4125                         return null; // nothing to compare
4126                 }
4127                 $authors = [];
4128                 $old_cmp = '>';
4129                 $new_cmp = '<';
4130                 $options = (array)$options;
4131                 if ( in_array( 'include_old', $options ) ) {
4132                         $old_cmp = '>=';
4133                 }
4134                 if ( in_array( 'include_new', $options ) ) {
4135                         $new_cmp = '<=';
4136                 }
4137                 if ( in_array( 'include_both', $options ) ) {
4138                         $old_cmp = '>=';
4139                         $new_cmp = '<=';
4140                 }
4141                 // No DB query needed if $old and $new are the same or successive revisions:
4142                 if ( $old->getId() === $new->getId() ) {
4143                         return ( $old_cmp === '>' && $new_cmp === '<' ) ?
4144                                 [] :
4145                                 [ $old->getUserText( Revision::RAW ) ];
4146                 } elseif ( $old->getId() === $new->getParentId() ) {
4147                         if ( $old_cmp === '>=' && $new_cmp === '<=' ) {
4148                                 $authors[] = $old->getUserText( Revision::RAW );
4149                                 if ( $old->getUserText( Revision::RAW ) != $new->getUserText( Revision::RAW ) ) {
4150                                         $authors[] = $new->getUserText( Revision::RAW );
4151                                 }
4152                         } elseif ( $old_cmp === '>=' ) {
4153                                 $authors[] = $old->getUserText( Revision::RAW );
4154                         } elseif ( $new_cmp === '<=' ) {
4155                                 $authors[] = $new->getUserText( Revision::RAW );
4156                         }
4157                         return $authors;
4158                 }
4159                 $dbr = wfGetDB( DB_SLAVE );
4160                 $res = $dbr->select( 'revision', 'DISTINCT rev_user_text',
4161                         [
4162                                 'rev_page' => $this->getArticleID(),
4163                                 "rev_timestamp $old_cmp " . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4164                                 "rev_timestamp $new_cmp " . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4165                         ], __METHOD__,
4166                         [ 'LIMIT' => $limit + 1 ] // add one so caller knows it was truncated
4167                 );
4168                 foreach ( $res as $row ) {
4169                         $authors[] = $row->rev_user_text;
4170                 }
4171                 return $authors;
4172         }
4173
4174         /**
4175          * Get the number of authors between the given revisions or revision IDs.
4176          * Used for diffs and other things that really need it.
4177          *
4178          * @param int|Revision $old Old revision or rev ID (first before range by default)
4179          * @param int|Revision $new New revision or rev ID (first after range by default)
4180          * @param int $limit Maximum number of authors
4181          * @param string|array $options (Optional): Single option, or an array of options:
4182          *     'include_old' Include $old in the range; $new is excluded.
4183          *     'include_new' Include $new in the range; $old is excluded.
4184          *     'include_both' Include both $old and $new in the range.
4185          *     Unknown option values are ignored.
4186          * @return int Number of revision authors in the range; zero if not both revisions exist
4187          */
4188         public function countAuthorsBetween( $old, $new, $limit, $options = [] ) {
4189                 $authors = $this->getAuthorsBetween( $old, $new, $limit, $options );
4190                 return $authors ? count( $authors ) : 0;
4191         }
4192
4193         /**
4194          * Compare with another title.
4195          *
4196          * @param Title $title
4197          * @return bool
4198          */
4199         public function equals( Title $title ) {
4200                 // Note: === is necessary for proper matching of number-like titles.
4201                 return $this->getInterwiki() === $title->getInterwiki()
4202                         && $this->getNamespace() == $title->getNamespace()
4203                         && $this->getDBkey() === $title->getDBkey();
4204         }
4205
4206         /**
4207          * Check if this title is a subpage of another title
4208          *
4209          * @param Title $title
4210          * @return bool
4211          */
4212         public function isSubpageOf( Title $title ) {
4213                 return $this->getInterwiki() === $title->getInterwiki()
4214                         && $this->getNamespace() == $title->getNamespace()
4215                         && strpos( $this->getDBkey(), $title->getDBkey() . '/' ) === 0;
4216         }
4217
4218         /**
4219          * Check if page exists.  For historical reasons, this function simply
4220          * checks for the existence of the title in the page table, and will
4221          * thus return false for interwiki links, special pages and the like.
4222          * If you want to know if a title can be meaningfully viewed, you should
4223          * probably call the isKnown() method instead.
4224          *
4225          * @param int $flags An optional bit field; may be Title::GAID_FOR_UPDATE to check
4226          *   from master/for update
4227          * @return bool
4228          */
4229         public function exists( $flags = 0 ) {
4230                 $exists = $this->getArticleID( $flags ) != 0;
4231                 Hooks::run( 'TitleExists', [ $this, &$exists ] );
4232                 return $exists;
4233         }
4234
4235         /**
4236          * Should links to this title be shown as potentially viewable (i.e. as
4237          * "bluelinks"), even if there's no record by this title in the page
4238          * table?
4239          *
4240          * This function is semi-deprecated for public use, as well as somewhat
4241          * misleadingly named.  You probably just want to call isKnown(), which
4242          * calls this function internally.
4243          *
4244          * (ISSUE: Most of these checks are cheap, but the file existence check
4245          * can potentially be quite expensive.  Including it here fixes a lot of
4246          * existing code, but we might want to add an optional parameter to skip
4247          * it and any other expensive checks.)
4248          *
4249          * @return bool
4250          */
4251         public function isAlwaysKnown() {
4252                 $isKnown = null;
4253
4254                 /**
4255                  * Allows overriding default behavior for determining if a page exists.
4256                  * If $isKnown is kept as null, regular checks happen. If it's
4257                  * a boolean, this value is returned by the isKnown method.
4258                  *
4259                  * @since 1.20
4260                  *
4261                  * @param Title $title
4262                  * @param bool|null $isKnown
4263                  */
4264                 Hooks::run( 'TitleIsAlwaysKnown', [ $this, &$isKnown ] );
4265
4266                 if ( !is_null( $isKnown ) ) {
4267                         return $isKnown;
4268                 }
4269
4270                 if ( $this->isExternal() ) {
4271                         return true;  // any interwiki link might be viewable, for all we know
4272                 }
4273
4274                 switch ( $this->mNamespace ) {
4275                         case NS_MEDIA:
4276                         case NS_FILE:
4277                                 // file exists, possibly in a foreign repo
4278                                 return (bool)wfFindFile( $this );
4279                         case NS_SPECIAL:
4280                                 // valid special page
4281                                 return SpecialPageFactory::exists( $this->getDBkey() );
4282                         case NS_MAIN:
4283                                 // selflink, possibly with fragment
4284                                 return $this->mDbkeyform == '';
4285                         case NS_MEDIAWIKI:
4286                                 // known system message
4287                                 return $this->hasSourceText() !== false;
4288                         default:
4289                                 return false;
4290                 }
4291         }
4292
4293         /**
4294          * Does this title refer to a page that can (or might) be meaningfully
4295          * viewed?  In particular, this function may be used to determine if
4296          * links to the title should be rendered as "bluelinks" (as opposed to
4297          * "redlinks" to non-existent pages).
4298          * Adding something else to this function will cause inconsistency
4299          * since LinkHolderArray calls isAlwaysKnown() and does its own
4300          * page existence check.
4301          *
4302          * @return bool
4303          */
4304         public function isKnown() {
4305                 return $this->isAlwaysKnown() || $this->exists();
4306         }
4307
4308         /**
4309          * Does this page have source text?
4310          *
4311          * @return bool
4312          */
4313         public function hasSourceText() {
4314                 if ( $this->exists() ) {
4315                         return true;
4316                 }
4317
4318                 if ( $this->mNamespace == NS_MEDIAWIKI ) {
4319                         // If the page doesn't exist but is a known system message, default
4320                         // message content will be displayed, same for language subpages-
4321                         // Use always content language to avoid loading hundreds of languages
4322                         // to get the link color.
4323                         global $wgContLang;
4324                         list( $name, ) = MessageCache::singleton()->figureMessage(
4325                                 $wgContLang->lcfirst( $this->getText() )
4326                         );
4327                         $message = wfMessage( $name )->inLanguage( $wgContLang )->useDatabase( false );
4328                         return $message->exists();
4329                 }
4330
4331                 return false;
4332         }
4333
4334         /**
4335          * Get the default message text or false if the message doesn't exist
4336          *
4337          * @return string|bool
4338          */
4339         public function getDefaultMessageText() {
4340                 global $wgContLang;
4341
4342                 if ( $this->getNamespace() != NS_MEDIAWIKI ) { // Just in case
4343                         return false;
4344                 }
4345
4346                 list( $name, $lang ) = MessageCache::singleton()->figureMessage(
4347                         $wgContLang->lcfirst( $this->getText() )
4348                 );
4349                 $message = wfMessage( $name )->inLanguage( $lang )->useDatabase( false );
4350
4351                 if ( $message->exists() ) {
4352                         return $message->plain();
4353                 } else {
4354                         return false;
4355                 }
4356         }
4357
4358         /**
4359          * Updates page_touched for this page; called from LinksUpdate.php
4360          *
4361          * @param string $purgeTime [optional] TS_MW timestamp
4362          * @return bool True if the update succeeded
4363          */
4364         public function invalidateCache( $purgeTime = null ) {
4365                 if ( wfReadOnly() ) {
4366                         return false;
4367                 }
4368
4369                 if ( $this->mArticleID === 0 ) {
4370                         return true; // avoid gap locking if we know it's not there
4371                 }
4372
4373                 $method = __METHOD__;
4374                 $dbw = wfGetDB( DB_MASTER );
4375                 $conds = $this->pageCond();
4376                 $dbw->onTransactionIdle( function () use ( $dbw, $conds, $method, $purgeTime ) {
4377                         $dbTimestamp = $dbw->timestamp( $purgeTime ?: time() );
4378
4379                         $dbw->update(
4380                                 'page',
4381                                 [ 'page_touched' => $dbTimestamp ],
4382                                 $conds + [ 'page_touched < ' . $dbw->addQuotes( $dbTimestamp ) ],
4383                                 $method
4384                         );
4385                 } );
4386
4387                 return true;
4388         }
4389
4390         /**
4391          * Update page_touched timestamps and send CDN purge messages for
4392          * pages linking to this title. May be sent to the job queue depending
4393          * on the number of links. Typically called on create and delete.
4394          */
4395         public function touchLinks() {
4396                 DeferredUpdates::addUpdate( new HTMLCacheUpdate( $this, 'pagelinks' ) );
4397                 if ( $this->getNamespace() == NS_CATEGORY ) {
4398                         DeferredUpdates::addUpdate( new HTMLCacheUpdate( $this, 'categorylinks' ) );
4399                 }
4400         }
4401
4402         /**
4403          * Get the last touched timestamp
4404          *
4405          * @param IDatabase $db Optional db
4406          * @return string Last-touched timestamp
4407          */
4408         public function getTouched( $db = null ) {
4409                 if ( $db === null ) {
4410                         $db = wfGetDB( DB_SLAVE );
4411                 }
4412                 $touched = $db->selectField( 'page', 'page_touched', $this->pageCond(), __METHOD__ );
4413                 return $touched;
4414         }
4415
4416         /**
4417          * Get the timestamp when this page was updated since the user last saw it.
4418          *
4419          * @param User $user
4420          * @return string|null
4421          */
4422         public function getNotificationTimestamp( $user = null ) {
4423                 global $wgUser;
4424
4425                 // Assume current user if none given
4426                 if ( !$user ) {
4427                         $user = $wgUser;
4428                 }
4429                 // Check cache first
4430                 $uid = $user->getId();
4431                 if ( !$uid ) {
4432                         return false;
4433                 }
4434                 // avoid isset here, as it'll return false for null entries
4435                 if ( array_key_exists( $uid, $this->mNotificationTimestamp ) ) {
4436                         return $this->mNotificationTimestamp[$uid];
4437                 }
4438                 // Don't cache too much!
4439                 if ( count( $this->mNotificationTimestamp ) >= self::CACHE_MAX ) {
4440                         $this->mNotificationTimestamp = [];
4441                 }
4442
4443                 $store = MediaWikiServices::getInstance()->getWatchedItemStore();
4444                 $watchedItem = $store->getWatchedItem( $user, $this );
4445                 if ( $watchedItem ) {
4446                         $this->mNotificationTimestamp[$uid] = $watchedItem->getNotificationTimestamp();
4447                 } else {
4448                         $this->mNotificationTimestamp[$uid] = false;
4449                 }
4450
4451                 return $this->mNotificationTimestamp[$uid];
4452         }
4453
4454         /**
4455          * Generate strings used for xml 'id' names in monobook tabs
4456          *
4457          * @param string $prepend Defaults to 'nstab-'
4458          * @return string XML 'id' name
4459          */
4460         public function getNamespaceKey( $prepend = 'nstab-' ) {
4461                 global $wgContLang;
4462                 // Gets the subject namespace if this title
4463                 $namespace = MWNamespace::getSubject( $this->getNamespace() );
4464                 // Checks if canonical namespace name exists for namespace
4465                 if ( MWNamespace::exists( $this->getNamespace() ) ) {
4466                         // Uses canonical namespace name
4467                         $namespaceKey = MWNamespace::getCanonicalName( $namespace );
4468                 } else {
4469                         // Uses text of namespace
4470                         $namespaceKey = $this->getSubjectNsText();
4471                 }
4472                 // Makes namespace key lowercase
4473                 $namespaceKey = $wgContLang->lc( $namespaceKey );
4474                 // Uses main
4475                 if ( $namespaceKey == '' ) {
4476                         $namespaceKey = 'main';
4477                 }
4478                 // Changes file to image for backwards compatibility
4479                 if ( $namespaceKey == 'file' ) {
4480                         $namespaceKey = 'image';
4481                 }
4482                 return $prepend . $namespaceKey;
4483         }
4484
4485         /**
4486          * Get all extant redirects to this Title
4487          *
4488          * @param int|null $ns Single namespace to consider; null to consider all namespaces
4489          * @return Title[] Array of Title redirects to this title
4490          */
4491         public function getRedirectsHere( $ns = null ) {
4492                 $redirs = [];
4493
4494                 $dbr = wfGetDB( DB_SLAVE );
4495                 $where = [
4496                         'rd_namespace' => $this->getNamespace(),
4497                         'rd_title' => $this->getDBkey(),
4498                         'rd_from = page_id'
4499                 ];
4500                 if ( $this->isExternal() ) {
4501                         $where['rd_interwiki'] = $this->getInterwiki();
4502                 } else {
4503                         $where[] = 'rd_interwiki = ' . $dbr->addQuotes( '' ) . ' OR rd_interwiki IS NULL';
4504                 }
4505                 if ( !is_null( $ns ) ) {
4506                         $where['page_namespace'] = $ns;
4507                 }
4508
4509                 $res = $dbr->select(
4510                         [ 'redirect', 'page' ],
4511                         [ 'page_namespace', 'page_title' ],
4512                         $where,
4513                         __METHOD__
4514                 );
4515
4516                 foreach ( $res as $row ) {
4517                         $redirs[] = self::newFromRow( $row );
4518                 }
4519                 return $redirs;
4520         }
4521
4522         /**
4523          * Check if this Title is a valid redirect target
4524          *
4525          * @return bool
4526          */
4527         public function isValidRedirectTarget() {
4528                 global $wgInvalidRedirectTargets;
4529
4530                 if ( $this->isSpecialPage() ) {
4531                         // invalid redirect targets are stored in a global array, but explicitly disallow Userlogout here
4532                         if ( $this->isSpecial( 'Userlogout' ) ) {
4533                                 return false;
4534                         }
4535
4536                         foreach ( $wgInvalidRedirectTargets as $target ) {
4537                                 if ( $this->isSpecial( $target ) ) {
4538                                         return false;
4539                                 }
4540                         }
4541                 }
4542
4543                 return true;
4544         }
4545
4546         /**
4547          * Get a backlink cache object
4548          *
4549          * @return BacklinkCache
4550          */
4551         public function getBacklinkCache() {
4552                 return BacklinkCache::get( $this );
4553         }
4554
4555         /**
4556          * Whether the magic words __INDEX__ and __NOINDEX__ function for  this page.
4557          *
4558          * @return bool
4559          */
4560         public function canUseNoindex() {
4561                 global $wgContentNamespaces, $wgExemptFromUserRobotsControl;
4562
4563                 $bannedNamespaces = is_null( $wgExemptFromUserRobotsControl )
4564                         ? $wgContentNamespaces
4565                         : $wgExemptFromUserRobotsControl;
4566
4567                 return !in_array( $this->mNamespace, $bannedNamespaces );
4568
4569         }
4570
4571         /**
4572          * Returns the raw sort key to be used for categories, with the specified
4573          * prefix.  This will be fed to Collation::getSortKey() to get a
4574          * binary sortkey that can be used for actual sorting.
4575          *
4576          * @param string $prefix The prefix to be used, specified using
4577          *   {{defaultsort:}} or like [[Category:Foo|prefix]].  Empty for no
4578          *   prefix.
4579          * @return string
4580          */
4581         public function getCategorySortkey( $prefix = '' ) {
4582                 $unprefixed = $this->getText();
4583
4584                 // Anything that uses this hook should only depend
4585                 // on the Title object passed in, and should probably
4586                 // tell the users to run updateCollations.php --force
4587                 // in order to re-sort existing category relations.
4588                 Hooks::run( 'GetDefaultSortkey', [ $this, &$unprefixed ] );
4589                 if ( $prefix !== '' ) {
4590                         # Separate with a line feed, so the unprefixed part is only used as
4591                         # a tiebreaker when two pages have the exact same prefix.
4592                         # In UCA, tab is the only character that can sort above LF
4593                         # so we strip both of them from the original prefix.
4594                         $prefix = strtr( $prefix, "\n\t", '  ' );
4595                         return "$prefix\n$unprefixed";
4596                 }
4597                 return $unprefixed;
4598         }
4599
4600         /**
4601          * Returns the page language code saved in the database, if $wgPageLanguageUseDB is set
4602          * to true in LocalSettings.php, otherwise returns false. If there is no language saved in
4603          * the db, it will return NULL.
4604          *
4605          * @return string|null|bool
4606          */
4607         private function getDbPageLanguageCode() {
4608                 global $wgPageLanguageUseDB;
4609
4610                 // check, if the page language could be saved in the database, and if so and
4611                 // the value is not requested already, lookup the page language using LinkCache
4612                 if ( $wgPageLanguageUseDB && $this->mDbPageLanguage === false ) {
4613                         $linkCache = LinkCache::singleton();
4614                         $linkCache->addLinkObj( $this );
4615                         $this->mDbPageLanguage = $linkCache->getGoodLinkFieldObj( $this, 'lang' );
4616                 }
4617
4618                 return $this->mDbPageLanguage;
4619         }
4620
4621         /**
4622          * Get the language in which the content of this page is written in
4623          * wikitext. Defaults to $wgContLang, but in certain cases it can be
4624          * e.g. $wgLang (such as special pages, which are in the user language).
4625          *
4626          * @since 1.18
4627          * @return Language
4628          */
4629         public function getPageLanguage() {
4630                 global $wgLang, $wgLanguageCode;
4631                 if ( $this->isSpecialPage() ) {
4632                         // special pages are in the user language
4633                         return $wgLang;
4634                 }
4635
4636                 // Checking if DB language is set
4637                 $dbPageLanguage = $this->getDbPageLanguageCode();
4638                 if ( $dbPageLanguage ) {
4639                         return wfGetLangObj( $dbPageLanguage );
4640                 }
4641
4642                 if ( !$this->mPageLanguage || $this->mPageLanguage[1] !== $wgLanguageCode ) {
4643                         // Note that this may depend on user settings, so the cache should
4644                         // be only per-request.
4645                         // NOTE: ContentHandler::getPageLanguage() may need to load the
4646                         // content to determine the page language!
4647                         // Checking $wgLanguageCode hasn't changed for the benefit of unit
4648                         // tests.
4649                         $contentHandler = ContentHandler::getForTitle( $this );
4650                         $langObj = $contentHandler->getPageLanguage( $this );
4651                         $this->mPageLanguage = [ $langObj->getCode(), $wgLanguageCode ];
4652                 } else {
4653                         $langObj = wfGetLangObj( $this->mPageLanguage[0] );
4654                 }
4655
4656                 return $langObj;
4657         }
4658
4659         /**
4660          * Get the language in which the content of this page is written when
4661          * viewed by user. Defaults to $wgContLang, but in certain cases it can be
4662          * e.g. $wgLang (such as special pages, which are in the user language).
4663          *
4664          * @since 1.20
4665          * @return Language
4666          */
4667         public function getPageViewLanguage() {
4668                 global $wgLang;
4669
4670                 if ( $this->isSpecialPage() ) {
4671                         // If the user chooses a variant, the content is actually
4672                         // in a language whose code is the variant code.
4673                         $variant = $wgLang->getPreferredVariant();
4674                         if ( $wgLang->getCode() !== $variant ) {
4675                                 return Language::factory( $variant );
4676                         }
4677
4678                         return $wgLang;
4679                 }
4680
4681                 // Checking if DB language is set
4682                 $dbPageLanguage = $this->getDbPageLanguageCode();
4683                 if ( $dbPageLanguage ) {
4684                         $pageLang = wfGetLangObj( $dbPageLanguage );
4685                         $variant = $pageLang->getPreferredVariant();
4686                         if ( $pageLang->getCode() !== $variant ) {
4687                                 $pageLang = Language::factory( $variant );
4688                         }
4689
4690                         return $pageLang;
4691                 }
4692
4693                 // @note Can't be cached persistently, depends on user settings.
4694                 // @note ContentHandler::getPageViewLanguage() may need to load the
4695                 //   content to determine the page language!
4696                 $contentHandler = ContentHandler::getForTitle( $this );
4697                 $pageLang = $contentHandler->getPageViewLanguage( $this );
4698                 return $pageLang;
4699         }
4700
4701         /**
4702          * Get a list of rendered edit notices for this page.
4703          *
4704          * Array is keyed by the original message key, and values are rendered using parseAsBlock, so
4705          * they will already be wrapped in paragraphs.
4706          *
4707          * @since 1.21
4708          * @param int $oldid Revision ID that's being edited
4709          * @return array
4710          */
4711         public function getEditNotices( $oldid = 0 ) {
4712                 $notices = [];
4713
4714                 // Optional notice for the entire namespace
4715                 $editnotice_ns = 'editnotice-' . $this->getNamespace();
4716                 $msg = wfMessage( $editnotice_ns );
4717                 if ( $msg->exists() ) {
4718                         $html = $msg->parseAsBlock();
4719                         // Edit notices may have complex logic, but output nothing (T91715)
4720                         if ( trim( $html ) !== '' ) {
4721                                 $notices[$editnotice_ns] = Html::rawElement(
4722                                         'div',
4723                                         [ 'class' => [
4724                                                 'mw-editnotice',
4725                                                 'mw-editnotice-namespace',
4726                                                 Sanitizer::escapeClass( "mw-$editnotice_ns" )
4727                                         ] ],
4728                                         $html
4729                                 );
4730                         }
4731                 }
4732
4733                 if ( MWNamespace::hasSubpages( $this->getNamespace() ) ) {
4734                         // Optional notice for page itself and any parent page
4735                         $parts = explode( '/', $this->getDBkey() );
4736                         $editnotice_base = $editnotice_ns;
4737                         while ( count( $parts ) > 0 ) {
4738                                 $editnotice_base .= '-' . array_shift( $parts );
4739                                 $msg = wfMessage( $editnotice_base );
4740                                 if ( $msg->exists() ) {
4741                                         $html = $msg->parseAsBlock();
4742                                         if ( trim( $html ) !== '' ) {
4743                                                 $notices[$editnotice_base] = Html::rawElement(
4744                                                         'div',
4745                                                         [ 'class' => [
4746                                                                 'mw-editnotice',
4747                                                                 'mw-editnotice-base',
4748                                                                 Sanitizer::escapeClass( "mw-$editnotice_base" )
4749                                                         ] ],
4750                                                         $html
4751                                                 );
4752                                         }
4753                                 }
4754                         }
4755                 } else {
4756                         // Even if there are no subpages in namespace, we still don't want "/" in MediaWiki message keys
4757                         $editnoticeText = $editnotice_ns . '-' . strtr( $this->getDBkey(), '/', '-' );
4758                         $msg = wfMessage( $editnoticeText );
4759                         if ( $msg->exists() ) {
4760                                 $html = $msg->parseAsBlock();
4761                                 if ( trim( $html ) !== '' ) {
4762                                         $notices[$editnoticeText] = Html::rawElement(
4763                                                 'div',
4764                                                 [ 'class' => [
4765                                                         'mw-editnotice',
4766                                                         'mw-editnotice-page',
4767                                                         Sanitizer::escapeClass( "mw-$editnoticeText" )
4768                                                 ] ],
4769                                                 $html
4770                                         );
4771                                 }
4772                         }
4773                 }
4774
4775                 Hooks::run( 'TitleGetEditNotices', [ $this, $oldid, &$notices ] );
4776                 return $notices;
4777         }
4778
4779         /**
4780          * @return array
4781          */
4782         public function __sleep() {
4783                 return [
4784                         'mNamespace',
4785                         'mDbkeyform',
4786                         'mFragment',
4787                         'mInterwiki',
4788                         'mLocalInterwiki',
4789                         'mUserCaseDBKey',
4790                         'mDefaultNamespace',
4791                 ];
4792         }
4793
4794         public function __wakeup() {
4795                 $this->mArticleID = ( $this->mNamespace >= 0 ) ? -1 : 0;
4796                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
4797                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
4798         }
4799
4800 }