includes/Title.php

   1 <?php
   2 /**
   3  * Representation of a title within %MediaWiki.
   4  *
   5  * See title.txt
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License along
  18  * with this program; if not, write to the Free Software Foundation, Inc.,
  19  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  20  * http://www.gnu.org/copyleft/gpl.html
  21  *
  22  * @file
  23  */
  24
  25 /**
  26  * Represents a title within MediaWiki.
  27  * Optionally may contain an interwiki designation or namespace.
  28  * @note This class can fetch various kinds of data from the database;
  29  *       however, it does so inefficiently.
  30  * @note Consider using a TitleValue object instead. TitleValue is more lightweight
  31  *       and does not rely on global state or the database.
  32  */
  33 class Title implements LinkTarget {
  34         /** @var HashBagOStuff */
  35         static private $titleCache = null;
  36
  37         /**
  38          * Title::newFromText maintains a cache to avoid expensive re-normalization of
  39          * commonly used titles. On a batch operation this can become a memory leak
  40          * if not bounded. After hitting this many titles reset the cache.
  41          */
  42         const CACHE_MAX = 1000;
  43
  44         /**
  45          * Used to be GAID_FOR_UPDATE define. Used with getArticleID() and friends
  46          * to use the master DB
  47          */
  48         const GAID_FOR_UPDATE = 1;
  49
  50         /**
  51          * @name Private member variables
  52          * Please use the accessor functions instead.
  53          * @private
  54          */
  55         // @{
  56
  57         /** @var string Text form (spaces not underscores) of the main part */
  58         public $mTextform = '';
  59
  60         /** @var string URL-encoded form of the main part */
  61         public $mUrlform = '';
  62
  63         /** @var string Main part with underscores */
  64         public $mDbkeyform = '';
  65
  66         /** @var string Database key with the initial letter in the case specified by the user */
  67         protected $mUserCaseDBKey;
  68
  69         /** @var int Namespace index, i.e. one of the NS_xxxx constants */
  70         public $mNamespace = NS_MAIN;
  71
  72         /** @var string Interwiki prefix */
  73         public $mInterwiki = '';
  74
  75         /** @var bool Was this Title created from a string with a local interwiki prefix? */
  76         private $mLocalInterwiki = false;
  77
  78         /** @var string Title fragment (i.e. the bit after the #) */
  79         public $mFragment = '';
  80
  81         /** @var int Article ID, fetched from the link cache on demand */
  82         public $mArticleID = -1;
  83
  84         /** @var bool|int ID of most recent revision */
  85         protected $mLatestID = false;
  86
  87         /**
  88          * @var bool|string ID of the page's content model, i.e. one of the
  89          *   CONTENT_MODEL_XXX constants
  90          */
  91         public $mContentModel = false;
  92
  93         /** @var int Estimated number of revisions; null of not loaded */
  94         private $mEstimateRevisions;
  95
  96         /** @var array Array of groups allowed to edit this article */
  97         public $mRestrictions = [];
  98
  99         /** @var string|bool */
 100         protected $mOldRestrictions = false;
 101
 102         /** @var bool Cascade restrictions on this page to included templates and images? */
 103         public $mCascadeRestriction;
 104
 105         /** Caching the results of getCascadeProtectionSources */
 106         public $mCascadingRestrictions;
 107
 108         /** @var array When do the restrictions on this page expire? */
 109         protected $mRestrictionsExpiry = [];
 110
 111         /** @var bool Are cascading restrictions in effect on this page? */
 112         protected $mHasCascadingRestrictions;
 113
 114         /** @var array Where are the cascading restrictions coming from on this page? */
 115         public $mCascadeSources;
 116
 117         /** @var bool Boolean for initialisation on demand */
 118         public $mRestrictionsLoaded = false;
 119
 120         /** @var string Text form including namespace/interwiki, initialised on demand */
 121         protected $mPrefixedText = null;
 122
 123         /** @var mixed Cached value for getTitleProtection (create protection) */
 124         public $mTitleProtection;
 125
 126         /**
 127          * @var int Namespace index when there is no namespace. Don't change the
 128          *   following default, NS_MAIN is hardcoded in several places. See bug 696.
 129          *   Zero except in {{transclusion}} tags.
 130          */
 131         public $mDefaultNamespace = NS_MAIN;
 132
 133         /** @var int The page length, 0 for special pages */
 134         protected $mLength = -1;
 135
 136         /** @var null Is the article at this title a redirect? */
 137         public $mRedirect = null;
 138
 139         /** @var array Associative array of user ID -> timestamp/false */
 140         private $mNotificationTimestamp = [];
 141
 142         /** @var bool Whether a page has any subpages */
 143         private $mHasSubpages;
 144
 145         /** @var bool The (string) language code of the page's language and content code. */
 146         private $mPageLanguage = false;
 147
 148         /** @var string|bool|null The page language code from the database, null if not saved in
 149          * the database or false if not loaded, yet. */
 150         private $mDbPageLanguage = false;
 151
 152         /** @var TitleValue A corresponding TitleValue object */
 153         private $mTitleValue = null;
 154
 155         /** @var bool Would deleting this page be a big deletion? */
 156         private $mIsBigDeletion = null;
 157         // @}
 158
 159         /**
 160          * B/C kludge: provide a TitleParser for use by Title.
 161          * Ideally, Title would have no methods that need this.
 162          * Avoid usage of this singleton by using TitleValue
 163          * and the associated services when possible.
 164          *
 165          * @return MediaWikiTitleCodec
 166          */
 167         private static function getMediaWikiTitleCodec() {
 168                 global $wgContLang, $wgLocalInterwikis;
 169
 170                 static $titleCodec = null;
 171                 static $titleCodecFingerprint = null;
 172
 173                 // $wgContLang and $wgLocalInterwikis may change (especially while testing),
 174                 // make sure we are using the right one. To detect changes over the course
 175                 // of a request, we remember a fingerprint of the config used to create the
 176                 // codec singleton, and re-create it if the fingerprint doesn't match.
 177                 $fingerprint = spl_object_hash( $wgContLang ) . '|' . implode( '+', $wgLocalInterwikis );
 178
 179                 if ( $fingerprint !== $titleCodecFingerprint ) {
 180                         $titleCodec = null;
 181                 }
 182
 183                 if ( !$titleCodec ) {
 184                         $titleCodec = new MediaWikiTitleCodec(
 185                                 $wgContLang,
 186                                 GenderCache::singleton(),
 187                                 $wgLocalInterwikis
 188                         );
 189                         $titleCodecFingerprint = $fingerprint;
 190                 }
 191
 192                 return $titleCodec;
 193         }
 194
 195         /**
 196          * B/C kludge: provide a TitleParser for use by Title.
 197          * Ideally, Title would have no methods that need this.
 198          * Avoid usage of this singleton by using TitleValue
 199          * and the associated services when possible.
 200          *
 201          * @return TitleFormatter
 202          */
 203         private static function getTitleFormatter() {
 204                 // NOTE: we know that getMediaWikiTitleCodec() returns a MediaWikiTitleCodec,
 205                 //      which implements TitleFormatter.
 206                 return self::getMediaWikiTitleCodec();
 207         }
 208
 209         function __construct() {
 210         }
 211
 212         /**
 213          * Create a new Title from a prefixed DB key
 214          *
 215          * @param string $key The database key, which has underscores
 216          *      instead of spaces, possibly including namespace and
 217          *      interwiki prefixes
 218          * @return Title|null Title, or null on an error
 219          */
 220         public static function newFromDBkey( $key ) {
 221                 $t = new Title();
 222                 $t->mDbkeyform = $key;
 223
 224                 try {
 225                         $t->secureAndSplit();
 226                         return $t;
 227                 } catch ( MalformedTitleException $ex ) {
 228                         return null;
 229                 }
 230         }
 231
 232         /**
 233          * Create a new Title from a TitleValue
 234          *
 235          * @param TitleValue $titleValue Assumed to be safe.
 236          *
 237          * @return Title
 238          */
 239         public static function newFromTitleValue( TitleValue $titleValue ) {
 240                 return self::newFromLinkTarget( $titleValue );
 241         }
 242
 243         /**
 244          * Create a new Title from a LinkTarget
 245          *
 246          * @param LinkTarget $linkTarget Assumed to be safe.
 247          *
 248          * @return Title
 249          */
 250         public static function newFromLinkTarget( LinkTarget $linkTarget ) {
 251                 return self::makeTitle(
 252                         $linkTarget->getNamespace(),
 253                         $linkTarget->getText(),
 254                         $linkTarget->getFragment() );
 255         }
 256
 257         /**
 258          * Create a new Title from text, such as what one would find in a link. De-
 259          * codes any HTML entities in the text.
 260          *
 261          * @param string|int|null $text The link text; spaces, prefixes, and an
 262          *   initial ':' indicating the main namespace are accepted.
 263          * @param int $defaultNamespace The namespace to use if none is specified
 264          *   by a prefix.  If you want to force a specific namespace even if
 265          *   $text might begin with a namespace prefix, use makeTitle() or
 266          *   makeTitleSafe().
 267          * @throws InvalidArgumentException
 268          * @return Title|null Title or null on an error.
 269          */
 270         public static function newFromText( $text, $defaultNamespace = NS_MAIN ) {
 271                 if ( is_object( $text ) ) {
 272                         throw new InvalidArgumentException( '$text must be a string.' );
 273                 }
 274                 // DWIM: Integers can be passed in here when page titles are used as array keys.
 275                 if ( $text !== null && !is_string( $text ) && !is_int( $text ) ) {
 276                         wfDebugLog( 'T76305', wfGetAllCallers( 5 ) );
 277                         return null;
 278                 }
 279                 if ( $text === null ) {
 280                         return null;
 281                 }
 282
 283                 try {
 284                         return Title::newFromTextThrow( strval( $text ), $defaultNamespace );
 285                 } catch ( MalformedTitleException $ex ) {
 286                         return null;
 287                 }
 288         }
 289
 290         /**
 291          * Like Title::newFromText(), but throws MalformedTitleException when the title is invalid,
 292          * rather than returning null.
 293          *
 294          * The exception subclasses encode detailed information about why the title is invalid.
 295          *
 296          * @see Title::newFromText
 297          *
 298          * @since 1.25
 299          * @param string $text Title text to check
 300          * @param int $defaultNamespace
 301          * @throws MalformedTitleException If the title is invalid
 302          * @return Title
 303          */
 304         public static function newFromTextThrow( $text, $defaultNamespace = NS_MAIN ) {
 305                 if ( is_object( $text ) ) {
 306                         throw new MWException( '$text must be a string, given an object' );
 307                 }
 308
 309                 $titleCache = self::getTitleCache();
 310
 311                 // Wiki pages often contain multiple links to the same page.
 312                 // Title normalization and parsing can become expensive on pages with many
 313                 // links, so we can save a little time by caching them.
 314                 // In theory these are value objects and won't get changed...
 315                 if ( $defaultNamespace == NS_MAIN ) {
 316                         $t = $titleCache->get( $text );
 317                         if ( $t ) {
 318                                 return $t;
 319                         }
 320                 }
 321
 322                 // Convert things like &eacute; &#257; or &#x3017; into normalized (bug 14952) text
 323                 $filteredText = Sanitizer::decodeCharReferencesAndNormalize( $text );
 324
 325                 $t = new Title();
 326                 $t->mDbkeyform = strtr( $filteredText, ' ', '_' );
 327                 $t->mDefaultNamespace = intval( $defaultNamespace );
 328
 329                 $t->secureAndSplit();
 330                 if ( $defaultNamespace == NS_MAIN ) {
 331                         $titleCache->set( $text, $t );
 332                 }
 333                 return $t;
 334         }
 335
 336         /**
 337          * THIS IS NOT THE FUNCTION YOU WANT. Use Title::newFromText().
 338          *
 339          * Example of wrong and broken code:
 340          * $title = Title::newFromURL( $wgRequest->getVal( 'title' ) );
 341          *
 342          * Example of right code:
 343          * $title = Title::newFromText( $wgRequest->getVal( 'title' ) );
 344          *
 345          * Create a new Title from URL-encoded text. Ensures that
 346          * the given title's length does not exceed the maximum.
 347          *
 348          * @param string $url The title, as might be taken from a URL
 349          * @return Title|null The new object, or null on an error
 350          */
 351         public static function newFromURL( $url ) {
 352                 $t = new Title();
 353
 354                 # For compatibility with old buggy URLs. "+" is usually not valid in titles,
 355                 # but some URLs used it as a space replacement and they still come
 356                 # from some external search tools.
 357                 if ( strpos( self::legalChars(), '+' ) === false ) {
 358                         $url = strtr( $url, '+', ' ' );
 359                 }
 360
 361                 $t->mDbkeyform = strtr( $url, ' ', '_' );
 362
 363                 try {
 364                         $t->secureAndSplit();
 365                         return $t;
 366                 } catch ( MalformedTitleException $ex ) {
 367                         return null;
 368                 }
 369         }
 370
 371         /**
 372          * @return HashBagOStuff
 373          */
 374         private static function getTitleCache() {
 375                 if ( self::$titleCache == null ) {
 376                         self::$titleCache = new HashBagOStuff( [ 'maxKeys' => self::CACHE_MAX ] );
 377                 }
 378                 return self::$titleCache;
 379         }
 380
 381         /**
 382          * Returns a list of fields that are to be selected for initializing Title
 383          * objects or LinkCache entries. Uses $wgContentHandlerUseDB to determine
 384          * whether to include page_content_model.
 385          *
 386          * @return array
 387          */
 388         protected static function getSelectFields() {
 389                 global $wgContentHandlerUseDB, $wgPageLanguageUseDB;
 390
 391                 $fields = [
 392                         'page_namespace', 'page_title', 'page_id',
 393                         'page_len', 'page_is_redirect', 'page_latest',
 394                 ];
 395
 396                 if ( $wgContentHandlerUseDB ) {
 397                         $fields[] = 'page_content_model';
 398                 }
 399
 400                 if ( $wgPageLanguageUseDB ) {
 401                         $fields[] = 'page_lang';
 402                 }
 403
 404                 return $fields;
 405         }
 406
 407         /**
 408          * Create a new Title from an article ID
 409          *
 410          * @param int $id The page_id corresponding to the Title to create
 411          * @param int $flags Use Title::GAID_FOR_UPDATE to use master
 412          * @return Title|null The new object, or null on an error
 413          */
 414         public static function newFromID( $id, $flags = 0 ) {
 415                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
 416                 $row = $db->selectRow(
 417                         'page',
 418                         self::getSelectFields(),
 419                         [ 'page_id' => $id ],
 420                         __METHOD__
 421                 );
 422                 if ( $row !== false ) {
 423                         $title = Title::newFromRow( $row );
 424                 } else {
 425                         $title = null;
 426                 }
 427                 return $title;
 428         }
 429
 430         /**
 431          * Make an array of titles from an array of IDs
 432          *
 433          * @param int[] $ids Array of IDs
 434          * @return Title[] Array of Titles
 435          */
 436         public static function newFromIDs( $ids ) {
 437                 if ( !count( $ids ) ) {
 438                         return [];
 439                 }
 440                 $dbr = wfGetDB( DB_SLAVE );
 441
 442                 $res = $dbr->select(
 443                         'page',
 444                         self::getSelectFields(),
 445                         [ 'page_id' => $ids ],
 446                         __METHOD__
 447                 );
 448
 449                 $titles = [];
 450                 foreach ( $res as $row ) {
 451                         $titles[] = Title::newFromRow( $row );
 452                 }
 453                 return $titles;
 454         }
 455
 456         /**
 457          * Make a Title object from a DB row
 458          *
 459          * @param stdClass $row Object database row (needs at least page_title,page_namespace)
 460          * @return Title Corresponding Title
 461          */
 462         public static function newFromRow( $row ) {
 463                 $t = self::makeTitle( $row->page_namespace, $row->page_title );
 464                 $t->loadFromRow( $row );
 465                 return $t;
 466         }
 467
 468         /**
 469          * Load Title object fields from a DB row.
 470          * If false is given, the title will be treated as non-existing.
 471          *
 472          * @param stdClass|bool $row Database row
 473          */
 474         public function loadFromRow( $row ) {
 475                 if ( $row ) { // page found
 476                         if ( isset( $row->page_id ) ) {
 477                                 $this->mArticleID = (int)$row->page_id;
 478                         }
 479                         if ( isset( $row->page_len ) ) {
 480                                 $this->mLength = (int)$row->page_len;
 481                         }
 482                         if ( isset( $row->page_is_redirect ) ) {
 483                                 $this->mRedirect = (bool)$row->page_is_redirect;
 484                         }
 485                         if ( isset( $row->page_latest ) ) {
 486                                 $this->mLatestID = (int)$row->page_latest;
 487                         }
 488                         if ( isset( $row->page_content_model ) ) {
 489                                 $this->mContentModel = strval( $row->page_content_model );
 490                         } else {
 491                                 $this->mContentModel = false; # initialized lazily in getContentModel()
 492                         }
 493                         if ( isset( $row->page_lang ) ) {
 494                                 $this->mDbPageLanguage = (string)$row->page_lang;
 495                         }
 496                         if ( isset( $row->page_restrictions ) ) {
 497                                 $this->mOldRestrictions = $row->page_restrictions;
 498                         }
 499                 } else { // page not found
 500                         $this->mArticleID = 0;
 501                         $this->mLength = 0;
 502                         $this->mRedirect = false;
 503                         $this->mLatestID = 0;
 504                         $this->mContentModel = false; # initialized lazily in getContentModel()
 505                 }
 506         }
 507
 508         /**
 509          * Create a new Title from a namespace index and a DB key.
 510          * It's assumed that $ns and $title are *valid*, for instance when
 511          * they came directly from the database or a special page name.
 512          * For convenience, spaces are converted to underscores so that
 513          * eg user_text fields can be used directly.
 514          *
 515          * @param int $ns The namespace of the article
 516          * @param string $title The unprefixed database key form
 517          * @param string $fragment The link fragment (after the "#")
 518          * @param string $interwiki The interwiki prefix
 519          * @return Title The new object
 520          */
 521         public static function &makeTitle( $ns, $title, $fragment = '', $interwiki = '' ) {
 522                 $t = new Title();
 523                 $t->mInterwiki = $interwiki;
 524                 $t->mFragment = $fragment;
 525                 $t->mNamespace = $ns = intval( $ns );
 526                 $t->mDbkeyform = strtr( $title, ' ', '_' );
 527                 $t->mArticleID = ( $ns >= 0 ) ? -1 : 0;
 528                 $t->mUrlform = wfUrlencode( $t->mDbkeyform );
 529                 $t->mTextform = strtr( $title, '_', ' ' );
 530                 $t->mContentModel = false; # initialized lazily in getContentModel()
 531                 return $t;
 532         }
 533
 534         /**
 535          * Create a new Title from a namespace index and a DB key.
 536          * The parameters will be checked for validity, which is a bit slower
 537          * than makeTitle() but safer for user-provided data.
 538          *
 539          * @param int $ns The namespace of the article
 540          * @param string $title Database key form
 541          * @param string $fragment The link fragment (after the "#")
 542          * @param string $interwiki Interwiki prefix
 543          * @return Title|null The new object, or null on an error
 544          */
 545         public static function makeTitleSafe( $ns, $title, $fragment = '', $interwiki = '' ) {
 546                 if ( !MWNamespace::exists( $ns ) ) {
 547                         return null;
 548                 }
 549
 550                 $t = new Title();
 551                 $t->mDbkeyform = Title::makeName( $ns, $title, $fragment, $interwiki, true );
 552
 553                 try {
 554                         $t->secureAndSplit();
 555                         return $t;
 556                 } catch ( MalformedTitleException $ex ) {
 557                         return null;
 558                 }
 559         }
 560
 561         /**
 562          * Create a new Title for the Main Page
 563          *
 564          * @return Title The new object
 565          */
 566         public static function newMainPage() {
 567                 $title = Title::newFromText( wfMessage( 'mainpage' )->inContentLanguage()->text() );
 568                 // Don't give fatal errors if the message is broken
 569                 if ( !$title ) {
 570                         $title = Title::newFromText( 'Main Page' );
 571                 }
 572                 return $title;
 573         }
 574
 575         /**
 576          * Extract a redirect destination from a string and return the
 577          * Title, or null if the text doesn't contain a valid redirect
 578          * This will recurse down $wgMaxRedirects times or until a non-redirect target is hit
 579          * in order to provide (hopefully) the Title of the final destination instead of another redirect
 580          *
 581          * @param string $text Text with possible redirect
 582          * @return Title
 583          * @deprecated since 1.21, use Content::getUltimateRedirectTarget instead.
 584          */
 585         public static function newFromRedirectRecurse( $text ) {
 586                 ContentHandler::deprecated( __METHOD__, '1.21' );
 587
 588                 $content = ContentHandler::makeContent( $text, null, CONTENT_MODEL_WIKITEXT );
 589                 return $content->getUltimateRedirectTarget();
 590         }
 591
 592         /**
 593          * Extract a redirect destination from a string and return an
 594          * array of Titles, or null if the text doesn't contain a valid redirect
 595          * The last element in the array is the final destination after all redirects
 596          * have been resolved (up to $wgMaxRedirects times)
 597          *
 598          * @param string $text Text with possible redirect
 599          * @return Title[] Array of Titles, with the destination last
 600          * @deprecated since 1.21, use Content::getRedirectChain instead.
 601          */
 602         public static function newFromRedirectArray( $text ) {
 603                 ContentHandler::deprecated( __METHOD__, '1.21' );
 604
 605                 $content = ContentHandler::makeContent( $text, null, CONTENT_MODEL_WIKITEXT );
 606                 return $content->getRedirectChain();
 607         }
 608
 609         /**
 610          * Get the prefixed DB key associated with an ID
 611          *
 612          * @param int $id The page_id of the article
 613          * @return Title|null An object representing the article, or null if no such article was found
 614          */
 615         public static function nameOf( $id ) {
 616                 $dbr = wfGetDB( DB_SLAVE );
 617
 618                 $s = $dbr->selectRow(
 619                         'page',
 620                         [ 'page_namespace', 'page_title' ],
 621                         [ 'page_id' => $id ],
 622                         __METHOD__
 623                 );
 624                 if ( $s === false ) {
 625                         return null;
 626                 }
 627
 628                 $n = self::makeName( $s->page_namespace, $s->page_title );
 629                 return $n;
 630         }
 631
 632         /**
 633          * Get a regex character class describing the legal characters in a link
 634          *
 635          * @return string The list of characters, not delimited
 636          */
 637         public static function legalChars() {
 638                 global $wgLegalTitleChars;
 639                 return $wgLegalTitleChars;
 640         }
 641
 642         /**
 643          * Returns a simple regex that will match on characters and sequences invalid in titles.
 644          * Note that this doesn't pick up many things that could be wrong with titles, but that
 645          * replacing this regex with something valid will make many titles valid.
 646          *
 647          * @deprecated since 1.25, use MediaWikiTitleCodec::getTitleInvalidRegex() instead
 648          *
 649          * @return string Regex string
 650          */
 651         static function getTitleInvalidRegex() {
 652                 wfDeprecated( __METHOD__, '1.25' );
 653                 return MediaWikiTitleCodec::getTitleInvalidRegex();
 654         }
 655
 656         /**
 657          * Utility method for converting a character sequence from bytes to Unicode.
 658          *
 659          * Primary usecase being converting $wgLegalTitleChars to a sequence usable in
 660          * javascript, as PHP uses UTF-8 bytes where javascript uses Unicode code units.
 661          *
 662          * @param string $byteClass
 663          * @return string
 664          */
 665         public static function convertByteClassToUnicodeClass( $byteClass ) {
 666                 $length = strlen( $byteClass );
 667                 // Input token queue
 668                 $x0 = $x1 = $x2 = '';
 669                 // Decoded queue
 670                 $d0 = $d1 = $d2 = '';
 671                 // Decoded integer codepoints
 672                 $ord0 = $ord1 = $ord2 = 0;
 673                 // Re-encoded queue
 674                 $r0 = $r1 = $r2 = '';
 675                 // Output
 676                 $out = '';
 677                 // Flags
 678                 $allowUnicode = false;
 679                 for ( $pos = 0; $pos < $length; $pos++ ) {
 680                         // Shift the queues down
 681                         $x2 = $x1;
 682                         $x1 = $x0;
 683                         $d2 = $d1;
 684                         $d1 = $d0;
 685                         $ord2 = $ord1;
 686                         $ord1 = $ord0;
 687                         $r2 = $r1;
 688                         $r1 = $r0;
 689                         // Load the current input token and decoded values
 690                         $inChar = $byteClass[$pos];
 691                         if ( $inChar == '\\' ) {
 692                                 if ( preg_match( '/x([0-9a-fA-F]{2})/A', $byteClass, $m, 0, $pos + 1 ) ) {
 693                                         $x0 = $inChar . $m[0];
 694                                         $d0 = chr( hexdec( $m[1] ) );
 695                                         $pos += strlen( $m[0] );
 696                                 } elseif ( preg_match( '/[0-7]{3}/A', $byteClass, $m, 0, $pos + 1 ) ) {
 697                                         $x0 = $inChar . $m[0];
 698                                         $d0 = chr( octdec( $m[0] ) );
 699                                         $pos += strlen( $m[0] );
 700                                 } elseif ( $pos + 1 >= $length ) {
 701                                         $x0 = $d0 = '\\';
 702                                 } else {
 703                                         $d0 = $byteClass[$pos + 1];
 704                                         $x0 = $inChar . $d0;
 705                                         $pos += 1;
 706                                 }
 707                         } else {
 708                                 $x0 = $d0 = $inChar;
 709                         }
 710                         $ord0 = ord( $d0 );
 711                         // Load the current re-encoded value
 712                         if ( $ord0 < 32 || $ord0 == 0x7f ) {
 713                                 $r0 = sprintf( '\x%02x', $ord0 );
 714                         } elseif ( $ord0 >= 0x80 ) {
 715                                 // Allow unicode if a single high-bit character appears
 716                                 $r0 = sprintf( '\x%02x', $ord0 );
 717                                 $allowUnicode = true;
 718                         } elseif ( strpos( '-\\[]^', $d0 ) !== false ) {
 719                                 $r0 = '\\' . $d0;
 720                         } else {
 721                                 $r0 = $d0;
 722                         }
 723                         // Do the output
 724                         if ( $x0 !== '' && $x1 === '-' && $x2 !== '' ) {
 725                                 // Range
 726                                 if ( $ord2 > $ord0 ) {
 727                                         // Empty range
 728                                 } elseif ( $ord0 >= 0x80 ) {
 729                                         // Unicode range
 730                                         $allowUnicode = true;
 731                                         if ( $ord2 < 0x80 ) {
 732                                                 // Keep the non-unicode section of the range
 733                                                 $out .= "$r2-\\x7F";
 734                                         }
 735                                 } else {
 736                                         // Normal range
 737                                         $out .= "$r2-$r0";
 738                                 }
 739                                 // Reset state to the initial value
 740                                 $x0 = $x1 = $d0 = $d1 = $r0 = $r1 = '';
 741                         } elseif ( $ord2 < 0x80 ) {
 742                                 // ASCII character
 743                                 $out .= $r2;
 744                         }
 745                 }
 746                 if ( $ord1 < 0x80 ) {
 747                         $out .= $r1;
 748                 }
 749                 if ( $ord0 < 0x80 ) {
 750                         $out .= $r0;
 751                 }
 752                 if ( $allowUnicode ) {
 753                         $out .= '\u0080-\uFFFF';
 754                 }
 755                 return $out;
 756         }
 757
 758         /**
 759          * Make a prefixed DB key from a DB key and a namespace index
 760          *
 761          * @param int $ns Numerical representation of the namespace
 762          * @param string $title The DB key form the title
 763          * @param string $fragment The link fragment (after the "#")
 764          * @param string $interwiki The interwiki prefix
 765          * @param bool $canonicalNamespace If true, use the canonical name for
 766          *   $ns instead of the localized version.
 767          * @return string The prefixed form of the title
 768          */
 769         public static function makeName( $ns, $title, $fragment = '', $interwiki = '',
 770                 $canonicalNamespace = false
 771         ) {
 772                 global $wgContLang;
 773
 774                 if ( $canonicalNamespace ) {
 775                         $namespace = MWNamespace::getCanonicalName( $ns );
 776                 } else {
 777                         $namespace = $wgContLang->getNsText( $ns );
 778                 }
 779                 $name = $namespace == '' ? $title : "$namespace:$title";
 780                 if ( strval( $interwiki ) != '' ) {
 781                         $name = "$interwiki:$name";
 782                 }
 783                 if ( strval( $fragment ) != '' ) {
 784                         $name .= '#' . $fragment;
 785                 }
 786                 return $name;
 787         }
 788
 789         /**
 790          * Escape a text fragment, say from a link, for a URL
 791          *
 792          * @param string $fragment Containing a URL or link fragment (after the "#")
 793          * @return string Escaped string
 794          */
 795         static function escapeFragmentForURL( $fragment ) {
 796                 # Note that we don't urlencode the fragment.  urlencoded Unicode
 797                 # fragments appear not to work in IE (at least up to 7) or in at least
 798                 # one version of Opera 9.x.  The W3C validator, for one, doesn't seem
 799                 # to care if they aren't encoded.
 800                 return Sanitizer::escapeId( $fragment, 'noninitial' );
 801         }
 802
 803         /**
 804          * Callback for usort() to do title sorts by (namespace, title)
 805          *
 806          * @param Title $a
 807          * @param Title $b
 808          *
 809          * @return int Result of string comparison, or namespace comparison
 810          */
 811         public static function compare( $a, $b ) {
 812                 if ( $a->getNamespace() == $b->getNamespace() ) {
 813                         return strcmp( $a->getText(), $b->getText() );
 814                 } else {
 815                         return $a->getNamespace() - $b->getNamespace();
 816                 }
 817         }
 818
 819         /**
 820          * Determine whether the object refers to a page within
 821          * this project (either this wiki or a wiki with a local
 822          * interwiki, see https://www.mediawiki.org/wiki/Manual:Interwiki_table#iw_local )
 823          *
 824          * @return bool True if this is an in-project interwiki link or a wikilink, false otherwise
 825          */
 826         public function isLocal() {
 827                 if ( $this->isExternal() ) {
 828                         $iw = Interwiki::fetch( $this->mInterwiki );
 829                         if ( $iw ) {
 830                                 return $iw->isLocal();
 831                         }
 832                 }
 833                 return true;
 834         }
 835
 836         /**
 837          * Is this Title interwiki?
 838          *
 839          * @return bool
 840          */
 841         public function isExternal() {
 842                 return $this->mInterwiki !== '';
 843         }
 844
 845         /**
 846          * Get the interwiki prefix
 847          *
 848          * Use Title::isExternal to check if a interwiki is set
 849          *
 850          * @return string Interwiki prefix
 851          */
 852         public function getInterwiki() {
 853                 return $this->mInterwiki;
 854         }
 855
 856         /**
 857          * Was this a local interwiki link?
 858          *
 859          * @return bool
 860          */
 861         public function wasLocalInterwiki() {
 862                 return $this->mLocalInterwiki;
 863         }
 864
 865         /**
 866          * Determine whether the object refers to a page within
 867          * this project and is transcludable.
 868          *
 869          * @return bool True if this is transcludable
 870          */
 871         public function isTrans() {
 872                 if ( !$this->isExternal() ) {
 873                         return false;
 874                 }
 875
 876                 return Interwiki::fetch( $this->mInterwiki )->isTranscludable();
 877         }
 878
 879         /**
 880          * Returns the DB name of the distant wiki which owns the object.
 881          *
 882          * @return string The DB name
 883          */
 884         public function getTransWikiID() {
 885                 if ( !$this->isExternal() ) {
 886                         return false;
 887                 }
 888
 889                 return Interwiki::fetch( $this->mInterwiki )->getWikiID();
 890         }
 891
 892         /**
 893          * Get a TitleValue object representing this Title.
 894          *
 895          * @note Not all valid Titles have a corresponding valid TitleValue
 896          * (e.g. TitleValues cannot represent page-local links that have a
 897          * fragment but no title text).
 898          *
 899          * @return TitleValue|null
 900          */
 901         public function getTitleValue() {
 902                 if ( $this->mTitleValue === null ) {
 903                         try {
 904                                 $this->mTitleValue = new TitleValue(
 905                                         $this->getNamespace(),
 906                                         $this->getDBkey(),
 907                                         $this->getFragment() );
 908                         } catch ( InvalidArgumentException $ex ) {
 909                                 wfDebug( __METHOD__ . ': Can\'t create a TitleValue for [[' .
 910                                         $this->getPrefixedText() . ']]: ' . $ex->getMessage() . "\n" );
 911                         }
 912                 }
 913
 914                 return $this->mTitleValue;
 915         }
 916
 917         /**
 918          * Get the text form (spaces not underscores) of the main part
 919          *
 920          * @return string Main part of the title
 921          */
 922         public function getText() {
 923                 return $this->mTextform;
 924         }
 925
 926         /**
 927          * Get the URL-encoded form of the main part
 928          *
 929          * @return string Main part of the title, URL-encoded
 930          */
 931         public function getPartialURL() {
 932                 return $this->mUrlform;
 933         }
 934
 935         /**
 936          * Get the main part with underscores
 937          *
 938          * @return string Main part of the title, with underscores
 939          */
 940         public function getDBkey() {
 941                 return $this->mDbkeyform;
 942         }
 943
 944         /**
 945          * Get the DB key with the initial letter case as specified by the user
 946          *
 947          * @return string DB key
 948          */
 949         function getUserCaseDBKey() {
 950                 if ( !is_null( $this->mUserCaseDBKey ) ) {
 951                         return $this->mUserCaseDBKey;
 952                 } else {
 953                         // If created via makeTitle(), $this->mUserCaseDBKey is not set.
 954                         return $this->mDbkeyform;
 955                 }
 956         }
 957
 958         /**
 959          * Get the namespace index, i.e. one of the NS_xxxx constants.
 960          *
 961          * @return int Namespace index
 962          */
 963         public function getNamespace() {
 964                 return $this->mNamespace;
 965         }
 966
 967         /**
 968          * Get the page's content model id, see the CONTENT_MODEL_XXX constants.
 969          *
 970          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
 971          * @return string Content model id
 972          */
 973         public function getContentModel( $flags = 0 ) {
 974                 if ( !$this->mContentModel && $this->getArticleID( $flags ) ) {
 975                         $linkCache = LinkCache::singleton();
 976                         $linkCache->addLinkObj( $this ); # in case we already had an article ID
 977                         $this->mContentModel = $linkCache->getGoodLinkFieldObj( $this, 'model' );
 978                 }
 979
 980                 if ( !$this->mContentModel ) {
 981                         $this->mContentModel = ContentHandler::getDefaultModelFor( $this );
 982                 }
 983
 984                 return $this->mContentModel;
 985         }
 986
 987         /**
 988          * Convenience method for checking a title's content model name
 989          *
 990          * @param string $id The content model ID (use the CONTENT_MODEL_XXX constants).
 991          * @return bool True if $this->getContentModel() == $id
 992          */
 993         public function hasContentModel( $id ) {
 994                 return $this->getContentModel() == $id;
 995         }
 996
 997         /**
 998          * Get the namespace text
 999          *
1000          * @return string Namespace text
1001          */
1002         public function getNsText() {
1003                 if ( $this->isExternal() ) {
1004                         // This probably shouldn't even happen,
1005                         // but for interwiki transclusion it sometimes does.
1006                         // Use the canonical namespaces if possible to try to
1007                         // resolve a foreign namespace.
1008                         if ( MWNamespace::exists( $this->mNamespace ) ) {
1009                                 return MWNamespace::getCanonicalName( $this->mNamespace );
1010                         }
1011                 }
1012
1013                 try {
1014                         $formatter = self::getTitleFormatter();
1015                         return $formatter->getNamespaceName( $this->mNamespace, $this->mDbkeyform );
1016                 } catch ( InvalidArgumentException $ex ) {
1017                         wfDebug( __METHOD__ . ': ' . $ex->getMessage() . "\n" );
1018                         return false;
1019                 }
1020         }
1021
1022         /**
1023          * Get the namespace text of the subject (rather than talk) page
1024          *
1025          * @return string Namespace text
1026          */
1027         public function getSubjectNsText() {
1028                 global $wgContLang;
1029                 return $wgContLang->getNsText( MWNamespace::getSubject( $this->mNamespace ) );
1030         }
1031
1032         /**
1033          * Get the namespace text of the talk page
1034          *
1035          * @return string Namespace text
1036          */
1037         public function getTalkNsText() {
1038                 global $wgContLang;
1039                 return $wgContLang->getNsText( MWNamespace::getTalk( $this->mNamespace ) );
1040         }
1041
1042         /**
1043          * Could this title have a corresponding talk page?
1044          *
1045          * @return bool
1046          */
1047         public function canTalk() {
1048                 return MWNamespace::canTalk( $this->mNamespace );
1049         }
1050
1051         /**
1052          * Is this in a namespace that allows actual pages?
1053          *
1054          * @return bool
1055          */
1056         public function canExist() {
1057                 return $this->mNamespace >= NS_MAIN;
1058         }
1059
1060         /**
1061          * Can this title be added to a user's watchlist?
1062          *
1063          * @return bool
1064          */
1065         public function isWatchable() {
1066                 return !$this->isExternal() && MWNamespace::isWatchable( $this->getNamespace() );
1067         }
1068
1069         /**
1070          * Returns true if this is a special page.
1071          *
1072          * @return bool
1073          */
1074         public function isSpecialPage() {
1075                 return $this->getNamespace() == NS_SPECIAL;
1076         }
1077
1078         /**
1079          * Returns true if this title resolves to the named special page
1080          *
1081          * @param string $name The special page name
1082          * @return bool
1083          */
1084         public function isSpecial( $name ) {
1085                 if ( $this->isSpecialPage() ) {
1086                         list( $thisName, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $this->getDBkey() );
1087                         if ( $name == $thisName ) {
1088                                 return true;
1089                         }
1090                 }
1091                 return false;
1092         }
1093
1094         /**
1095          * If the Title refers to a special page alias which is not the local default, resolve
1096          * the alias, and localise the name as necessary.  Otherwise, return $this
1097          *
1098          * @return Title
1099          */
1100         public function fixSpecialName() {
1101                 if ( $this->isSpecialPage() ) {
1102                         list( $canonicalName, $par ) = SpecialPageFactory::resolveAlias( $this->mDbkeyform );
1103                         if ( $canonicalName ) {
1104                                 $localName = SpecialPageFactory::getLocalNameFor( $canonicalName, $par );
1105                                 if ( $localName != $this->mDbkeyform ) {
1106                                         return Title::makeTitle( NS_SPECIAL, $localName );
1107                                 }
1108                         }
1109                 }
1110                 return $this;
1111         }
1112
1113         /**
1114          * Returns true if the title is inside the specified namespace.
1115          *
1116          * Please make use of this instead of comparing to getNamespace()
1117          * This function is much more resistant to changes we may make
1118          * to namespaces than code that makes direct comparisons.
1119          * @param int $ns The namespace
1120          * @return bool
1121          * @since 1.19
1122          */
1123         public function inNamespace( $ns ) {
1124                 return MWNamespace::equals( $this->getNamespace(), $ns );
1125         }
1126
1127         /**
1128          * Returns true if the title is inside one of the specified namespaces.
1129          *
1130          * @param int $namespaces,... The namespaces to check for
1131          * @return bool
1132          * @since 1.19
1133          */
1134         public function inNamespaces( /* ... */ ) {
1135                 $namespaces = func_get_args();
1136                 if ( count( $namespaces ) > 0 && is_array( $namespaces[0] ) ) {
1137                         $namespaces = $namespaces[0];
1138                 }
1139
1140                 foreach ( $namespaces as $ns ) {
1141                         if ( $this->inNamespace( $ns ) ) {
1142                                 return true;
1143                         }
1144                 }
1145
1146                 return false;
1147         }
1148
1149         /**
1150          * Returns true if the title has the same subject namespace as the
1151          * namespace specified.
1152          * For example this method will take NS_USER and return true if namespace
1153          * is either NS_USER or NS_USER_TALK since both of them have NS_USER
1154          * as their subject namespace.
1155          *
1156          * This is MUCH simpler than individually testing for equivalence
1157          * against both NS_USER and NS_USER_TALK, and is also forward compatible.
1158          * @since 1.19
1159          * @param int $ns
1160          * @return bool
1161          */
1162         public function hasSubjectNamespace( $ns ) {
1163                 return MWNamespace::subjectEquals( $this->getNamespace(), $ns );
1164         }
1165
1166         /**
1167          * Is this Title in a namespace which contains content?
1168          * In other words, is this a content page, for the purposes of calculating
1169          * statistics, etc?
1170          *
1171          * @return bool
1172          */
1173         public function isContentPage() {
1174                 return MWNamespace::isContent( $this->getNamespace() );
1175         }
1176
1177         /**
1178          * Would anybody with sufficient privileges be able to move this page?
1179          * Some pages just aren't movable.
1180          *
1181          * @return bool
1182          */
1183         public function isMovable() {
1184                 if ( !MWNamespace::isMovable( $this->getNamespace() ) || $this->isExternal() ) {
1185                         // Interwiki title or immovable namespace. Hooks don't get to override here
1186                         return false;
1187                 }
1188
1189                 $result = true;
1190                 Hooks::run( 'TitleIsMovable', [ $this, &$result ] );
1191                 return $result;
1192         }
1193
1194         /**
1195          * Is this the mainpage?
1196          * @note Title::newFromText seems to be sufficiently optimized by the title
1197          * cache that we don't need to over-optimize by doing direct comparisons and
1198          * accidentally creating new bugs where $title->equals( Title::newFromText() )
1199          * ends up reporting something differently than $title->isMainPage();
1200          *
1201          * @since 1.18
1202          * @return bool
1203          */
1204         public function isMainPage() {
1205                 return $this->equals( Title::newMainPage() );
1206         }
1207
1208         /**
1209          * Is this a subpage?
1210          *
1211          * @return bool
1212          */
1213         public function isSubpage() {
1214                 return MWNamespace::hasSubpages( $this->mNamespace )
1215                         ? strpos( $this->getText(), '/' ) !== false
1216                         : false;
1217         }
1218
1219         /**
1220          * Is this a conversion table for the LanguageConverter?
1221          *
1222          * @return bool
1223          */
1224         public function isConversionTable() {
1225                 // @todo ConversionTable should become a separate content model.
1226
1227                 return $this->getNamespace() == NS_MEDIAWIKI &&
1228                         strpos( $this->getText(), 'Conversiontable/' ) === 0;
1229         }
1230
1231         /**
1232          * Does that page contain wikitext, or it is JS, CSS or whatever?
1233          *
1234          * @return bool
1235          */
1236         public function isWikitextPage() {
1237                 return $this->hasContentModel( CONTENT_MODEL_WIKITEXT );
1238         }
1239
1240         /**
1241          * Could this page contain custom CSS or JavaScript for the global UI.
1242          * This is generally true for pages in the MediaWiki namespace having CONTENT_MODEL_CSS
1243          * or CONTENT_MODEL_JAVASCRIPT.
1244          *
1245          * This method does *not* return true for per-user JS/CSS. Use isCssJsSubpage()
1246          * for that!
1247          *
1248          * Note that this method should not return true for pages that contain and
1249          * show "inactive" CSS or JS.
1250          *
1251          * @return bool
1252          * @todo FIXME: Rename to isSiteConfigPage() and remove deprecated hook
1253          */
1254         public function isCssOrJsPage() {
1255                 $isCssOrJsPage = NS_MEDIAWIKI == $this->mNamespace
1256                         && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1257                                 || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1258
1259                 # @note This hook is also called in ContentHandler::getDefaultModel.
1260                 #   It's called here again to make sure hook functions can force this
1261                 #   method to return true even outside the MediaWiki namespace.
1262
1263                 Hooks::run( 'TitleIsCssOrJsPage', [ $this, &$isCssOrJsPage ], '1.25' );
1264
1265                 return $isCssOrJsPage;
1266         }
1267
1268         /**
1269          * Is this a .css or .js subpage of a user page?
1270          * @return bool
1271          * @todo FIXME: Rename to isUserConfigPage()
1272          */
1273         public function isCssJsSubpage() {
1274                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1275                                 && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1276                                         || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) ) );
1277         }
1278
1279         /**
1280          * Trim down a .css or .js subpage title to get the corresponding skin name
1281          *
1282          * @return string Containing skin name from .css or .js subpage title
1283          */
1284         public function getSkinFromCssJsSubpage() {
1285                 $subpage = explode( '/', $this->mTextform );
1286                 $subpage = $subpage[count( $subpage ) - 1];
1287                 $lastdot = strrpos( $subpage, '.' );
1288                 if ( $lastdot === false ) {
1289                         return $subpage; # Never happens: only called for names ending in '.css' or '.js'
1290                 }
1291                 return substr( $subpage, 0, $lastdot );
1292         }
1293
1294         /**
1295          * Is this a .css subpage of a user page?
1296          *
1297          * @return bool
1298          */
1299         public function isCssSubpage() {
1300                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1301                         && $this->hasContentModel( CONTENT_MODEL_CSS ) );
1302         }
1303
1304         /**
1305          * Is this a .js subpage of a user page?
1306          *
1307          * @return bool
1308          */
1309         public function isJsSubpage() {
1310                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1311                         && $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1312         }
1313
1314         /**
1315          * Is this a talk page of some sort?
1316          *
1317          * @return bool
1318          */
1319         public function isTalkPage() {
1320                 return MWNamespace::isTalk( $this->getNamespace() );
1321         }
1322
1323         /**
1324          * Get a Title object associated with the talk page of this article
1325          *
1326          * @return Title The object for the talk page
1327          */
1328         public function getTalkPage() {
1329                 return Title::makeTitle( MWNamespace::getTalk( $this->getNamespace() ), $this->getDBkey() );
1330         }
1331
1332         /**
1333          * Get a title object associated with the subject page of this
1334          * talk page
1335          *
1336          * @return Title The object for the subject page
1337          */
1338         public function getSubjectPage() {
1339                 // Is this the same title?
1340                 $subjectNS = MWNamespace::getSubject( $this->getNamespace() );
1341                 if ( $this->getNamespace() == $subjectNS ) {
1342                         return $this;
1343                 }
1344                 return Title::makeTitle( $subjectNS, $this->getDBkey() );
1345         }
1346
1347         /**
1348          * Get the other title for this page, if this is a subject page
1349          * get the talk page, if it is a subject page get the talk page
1350          *
1351          * @since 1.25
1352          * @throws MWException
1353          * @return Title
1354          */
1355         public function getOtherPage() {
1356                 if ( $this->isSpecialPage() ) {
1357                         throw new MWException( 'Special pages cannot have other pages' );
1358                 }
1359                 if ( $this->isTalkPage() ) {
1360                         return $this->getSubjectPage();
1361                 } else {
1362                         return $this->getTalkPage();
1363                 }
1364         }
1365
1366         /**
1367          * Get the default namespace index, for when there is no namespace
1368          *
1369          * @return int Default namespace index
1370          */
1371         public function getDefaultNamespace() {
1372                 return $this->mDefaultNamespace;
1373         }
1374
1375         /**
1376          * Get the Title fragment (i.e.\ the bit after the #) in text form
1377          *
1378          * Use Title::hasFragment to check for a fragment
1379          *
1380          * @return string Title fragment
1381          */
1382         public function getFragment() {
1383                 return $this->mFragment;
1384         }
1385
1386         /**
1387          * Check if a Title fragment is set
1388          *
1389          * @return bool
1390          * @since 1.23
1391          */
1392         public function hasFragment() {
1393                 return $this->mFragment !== '';
1394         }
1395
1396         /**
1397          * Get the fragment in URL form, including the "#" character if there is one
1398          * @return string Fragment in URL form
1399          */
1400         public function getFragmentForURL() {
1401                 if ( !$this->hasFragment() ) {
1402                         return '';
1403                 } else {
1404                         return '#' . Title::escapeFragmentForURL( $this->getFragment() );
1405                 }
1406         }
1407
1408         /**
1409          * Set the fragment for this title. Removes the first character from the
1410          * specified fragment before setting, so it assumes you're passing it with
1411          * an initial "#".
1412          *
1413          * Deprecated for public use, use Title::makeTitle() with fragment parameter.
1414          * Still in active use privately.
1415          *
1416          * @private
1417          * @param string $fragment Text
1418          */
1419         public function setFragment( $fragment ) {
1420                 $this->mFragment = strtr( substr( $fragment, 1 ), '_', ' ' );
1421         }
1422
1423         /**
1424          * Prefix some arbitrary text with the namespace or interwiki prefix
1425          * of this object
1426          *
1427          * @param string $name The text
1428          * @return string The prefixed text
1429          */
1430         private function prefix( $name ) {
1431                 $p = '';
1432                 if ( $this->isExternal() ) {
1433                         $p = $this->mInterwiki . ':';
1434                 }
1435
1436                 if ( 0 != $this->mNamespace ) {
1437                         $p .= $this->getNsText() . ':';
1438                 }
1439                 return $p . $name;
1440         }
1441
1442         /**
1443          * Get the prefixed database key form
1444          *
1445          * @return string The prefixed title, with underscores and
1446          *  any interwiki and namespace prefixes
1447          */
1448         public function getPrefixedDBkey() {
1449                 $s = $this->prefix( $this->mDbkeyform );
1450                 $s = strtr( $s, ' ', '_' );
1451                 return $s;
1452         }
1453
1454         /**
1455          * Get the prefixed title with spaces.
1456          * This is the form usually used for display
1457          *
1458          * @return string The prefixed title, with spaces
1459          */
1460         public function getPrefixedText() {
1461                 if ( $this->mPrefixedText === null ) {
1462                         $s = $this->prefix( $this->mTextform );
1463                         $s = strtr( $s, '_', ' ' );
1464                         $this->mPrefixedText = $s;
1465                 }
1466                 return $this->mPrefixedText;
1467         }
1468
1469         /**
1470          * Return a string representation of this title
1471          *
1472          * @return string Representation of this title
1473          */
1474         public function __toString() {
1475                 return $this->getPrefixedText();
1476         }
1477
1478         /**
1479          * Get the prefixed title with spaces, plus any fragment
1480          * (part beginning with '#')
1481          *
1482          * @return string The prefixed title, with spaces and the fragment, including '#'
1483          */
1484         public function getFullText() {
1485                 $text = $this->getPrefixedText();
1486                 if ( $this->hasFragment() ) {
1487                         $text .= '#' . $this->getFragment();
1488                 }
1489                 return $text;
1490         }
1491
1492         /**
1493          * Get the root page name text without a namespace, i.e. the leftmost part before any slashes
1494          *
1495          * @par Example:
1496          * @code
1497          * Title::newFromText('User:Foo/Bar/Baz')->getRootText();
1498          * # returns: 'Foo'
1499          * @endcode
1500          *
1501          * @return string Root name
1502          * @since 1.20
1503          */
1504         public function getRootText() {
1505                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1506                         return $this->getText();
1507                 }
1508
1509                 return strtok( $this->getText(), '/' );
1510         }
1511
1512         /**
1513          * Get the root page name title, i.e. the leftmost part before any slashes
1514          *
1515          * @par Example:
1516          * @code
1517          * Title::newFromText('User:Foo/Bar/Baz')->getRootTitle();
1518          * # returns: Title{User:Foo}
1519          * @endcode
1520          *
1521          * @return Title Root title
1522          * @since 1.20
1523          */
1524         public function getRootTitle() {
1525                 return Title::makeTitle( $this->getNamespace(), $this->getRootText() );
1526         }
1527
1528         /**
1529          * Get the base page name without a namespace, i.e. the part before the subpage name
1530          *
1531          * @par Example:
1532          * @code
1533          * Title::newFromText('User:Foo/Bar/Baz')->getBaseText();
1534          * # returns: 'Foo/Bar'
1535          * @endcode
1536          *
1537          * @return string Base name
1538          */
1539         public function getBaseText() {
1540                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1541                         return $this->getText();
1542                 }
1543
1544                 $parts = explode( '/', $this->getText() );
1545                 # Don't discard the real title if there's no subpage involved
1546                 if ( count( $parts ) > 1 ) {
1547                         unset( $parts[count( $parts ) - 1] );
1548                 }
1549                 return implode( '/', $parts );
1550         }
1551
1552         /**
1553          * Get the base page name title, i.e. the part before the subpage name
1554          *
1555          * @par Example:
1556          * @code
1557          * Title::newFromText('User:Foo/Bar/Baz')->getBaseTitle();
1558          * # returns: Title{User:Foo/Bar}
1559          * @endcode
1560          *
1561          * @return Title Base title
1562          * @since 1.20
1563          */
1564         public function getBaseTitle() {
1565                 return Title::makeTitle( $this->getNamespace(), $this->getBaseText() );
1566         }
1567
1568         /**
1569          * Get the lowest-level subpage name, i.e. the rightmost part after any slashes
1570          *
1571          * @par Example:
1572          * @code
1573          * Title::newFromText('User:Foo/Bar/Baz')->getSubpageText();
1574          * # returns: "Baz"
1575          * @endcode
1576          *
1577          * @return string Subpage name
1578          */
1579         public function getSubpageText() {
1580                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1581                         return $this->mTextform;
1582                 }
1583                 $parts = explode( '/', $this->mTextform );
1584                 return $parts[count( $parts ) - 1];
1585         }
1586
1587         /**
1588          * Get the title for a subpage of the current page
1589          *
1590          * @par Example:
1591          * @code
1592          * Title::newFromText('User:Foo/Bar/Baz')->getSubpage("Asdf");
1593          * # returns: Title{User:Foo/Bar/Baz/Asdf}
1594          * @endcode
1595          *
1596          * @param string $text The subpage name to add to the title
1597          * @return Title Subpage title
1598          * @since 1.20
1599          */
1600         public function getSubpage( $text ) {
1601                 return Title::makeTitleSafe( $this->getNamespace(), $this->getText() . '/' . $text );
1602         }
1603
1604         /**
1605          * Get a URL-encoded form of the subpage text
1606          *
1607          * @return string URL-encoded subpage name
1608          */
1609         public function getSubpageUrlForm() {
1610                 $text = $this->getSubpageText();
1611                 $text = wfUrlencode( strtr( $text, ' ', '_' ) );
1612                 return $text;
1613         }
1614
1615         /**
1616          * Get a URL-encoded title (not an actual URL) including interwiki
1617          *
1618          * @return string The URL-encoded form
1619          */
1620         public function getPrefixedURL() {
1621                 $s = $this->prefix( $this->mDbkeyform );
1622                 $s = wfUrlencode( strtr( $s, ' ', '_' ) );
1623                 return $s;
1624         }
1625
1626         /**
1627          * Helper to fix up the get{Canonical,Full,Link,Local,Internal}URL args
1628          * get{Canonical,Full,Link,Local,Internal}URL methods accepted an optional
1629          * second argument named variant. This was deprecated in favor
1630          * of passing an array of option with a "variant" key
1631          * Once $query2 is removed for good, this helper can be dropped
1632          * and the wfArrayToCgi moved to getLocalURL();
1633          *
1634          * @since 1.19 (r105919)
1635          * @param array|string $query
1636          * @param bool $query2
1637          * @return string
1638          */
1639         private static function fixUrlQueryArgs( $query, $query2 = false ) {
1640                 if ( $query2 !== false ) {
1641                         wfDeprecated( "Title::get{Canonical,Full,Link,Local,Internal}URL " .
1642                                 "method called with a second parameter is deprecated. Add your " .
1643                                 "parameter to an array passed as the first parameter.", "1.19" );
1644                 }
1645                 if ( is_array( $query ) ) {
1646                         $query = wfArrayToCgi( $query );
1647                 }
1648                 if ( $query2 ) {
1649                         if ( is_string( $query2 ) ) {
1650                                 // $query2 is a string, we will consider this to be
1651                                 // a deprecated $variant argument and add it to the query
1652                                 $query2 = wfArrayToCgi( [ 'variant' => $query2 ] );
1653                         } else {
1654                                 $query2 = wfArrayToCgi( $query2 );
1655                         }
1656                         // If we have $query content add a & to it first
1657                         if ( $query ) {
1658                                 $query .= '&';
1659                         }
1660                         // Now append the queries together
1661                         $query .= $query2;
1662                 }
1663                 return $query;
1664         }
1665
1666         /**
1667          * Get a real URL referring to this title, with interwiki link and
1668          * fragment
1669          *
1670          * @see self::getLocalURL for the arguments.
1671          * @see wfExpandUrl
1672          * @param array|string $query
1673          * @param bool $query2
1674          * @param string $proto Protocol type to use in URL
1675          * @return string The URL
1676          */
1677         public function getFullURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1678                 $query = self::fixUrlQueryArgs( $query, $query2 );
1679
1680                 # Hand off all the decisions on urls to getLocalURL
1681                 $url = $this->getLocalURL( $query );
1682
1683                 # Expand the url to make it a full url. Note that getLocalURL has the
1684                 # potential to output full urls for a variety of reasons, so we use
1685                 # wfExpandUrl instead of simply prepending $wgServer
1686                 $url = wfExpandUrl( $url, $proto );
1687
1688                 # Finally, add the fragment.
1689                 $url .= $this->getFragmentForURL();
1690
1691                 Hooks::run( 'GetFullURL', [ &$this, &$url, $query ] );
1692                 return $url;
1693         }
1694
1695         /**
1696          * Get a URL with no fragment or server name (relative URL) from a Title object.
1697          * If this page is generated with action=render, however,
1698          * $wgServer is prepended to make an absolute URL.
1699          *
1700          * @see self::getFullURL to always get an absolute URL.
1701          * @see self::getLinkURL to always get a URL that's the simplest URL that will be
1702          *  valid to link, locally, to the current Title.
1703          * @see self::newFromText to produce a Title object.
1704          *
1705          * @param string|array $query An optional query string,
1706          *   not used for interwiki links. Can be specified as an associative array as well,
1707          *   e.g., array( 'action' => 'edit' ) (keys and values will be URL-escaped).
1708          *   Some query patterns will trigger various shorturl path replacements.
1709          * @param array $query2 An optional secondary query array. This one MUST
1710          *   be an array. If a string is passed it will be interpreted as a deprecated
1711          *   variant argument and urlencoded into a variant= argument.
1712          *   This second query argument will be added to the $query
1713          *   The second parameter is deprecated since 1.19. Pass it as a key,value
1714          *   pair in the first parameter array instead.
1715          *
1716          * @return string String of the URL.
1717          */
1718         public function getLocalURL( $query = '', $query2 = false ) {
1719                 global $wgArticlePath, $wgScript, $wgServer, $wgRequest;
1720
1721                 $query = self::fixUrlQueryArgs( $query, $query2 );
1722
1723                 $interwiki = Interwiki::fetch( $this->mInterwiki );
1724                 if ( $interwiki ) {
1725                         $namespace = $this->getNsText();
1726                         if ( $namespace != '' ) {
1727                                 # Can this actually happen? Interwikis shouldn't be parsed.
1728                                 # Yes! It can in interwiki transclusion. But... it probably shouldn't.
1729                                 $namespace .= ':';
1730                         }
1731                         $url = $interwiki->getURL( $namespace . $this->getDBkey() );
1732                         $url = wfAppendQuery( $url, $query );
1733                 } else {
1734                         $dbkey = wfUrlencode( $this->getPrefixedDBkey() );
1735                         if ( $query == '' ) {
1736                                 $url = str_replace( '$1', $dbkey, $wgArticlePath );
1737                                 Hooks::run( 'GetLocalURL::Article', [ &$this, &$url ] );
1738                         } else {
1739                                 global $wgVariantArticlePath, $wgActionPaths, $wgContLang;
1740                                 $url = false;
1741                                 $matches = [];
1742
1743                                 if ( !empty( $wgActionPaths )
1744                                         && preg_match( '/^(.*&|)action=([^&]*)(&(.*)|)$/', $query, $matches )
1745                                 ) {
1746                                         $action = urldecode( $matches[2] );
1747                                         if ( isset( $wgActionPaths[$action] ) ) {
1748                                                 $query = $matches[1];
1749                                                 if ( isset( $matches[4] ) ) {
1750                                                         $query .= $matches[4];
1751                                                 }
1752                                                 $url = str_replace( '$1', $dbkey, $wgActionPaths[$action] );
1753                                                 if ( $query != '' ) {
1754                                                         $url = wfAppendQuery( $url, $query );
1755                                                 }
1756                                         }
1757                                 }
1758
1759                                 if ( $url === false
1760                                         && $wgVariantArticlePath
1761                                         && $wgContLang->getCode() === $this->getPageLanguage()->getCode()
1762                                         && $this->getPageLanguage()->hasVariants()
1763                                         && preg_match( '/^variant=([^&]*)$/', $query, $matches )
1764                                 ) {
1765                                         $variant = urldecode( $matches[1] );
1766                                         if ( $this->getPageLanguage()->hasVariant( $variant ) ) {
1767                                                 // Only do the variant replacement if the given variant is a valid
1768                                                 // variant for the page's language.
1769                                                 $url = str_replace( '$2', urlencode( $variant ), $wgVariantArticlePath );
1770                                                 $url = str_replace( '$1', $dbkey, $url );
1771                                         }
1772                                 }
1773
1774                                 if ( $url === false ) {
1775                                         if ( $query == '-' ) {
1776                                                 $query = '';
1777                                         }
1778                                         $url = "{$wgScript}?title={$dbkey}&{$query}";
1779                                 }
1780                         }
1781
1782                         Hooks::run( 'GetLocalURL::Internal', [ &$this, &$url, $query ] );
1783
1784                         // @todo FIXME: This causes breakage in various places when we
1785                         // actually expected a local URL and end up with dupe prefixes.
1786                         if ( $wgRequest->getVal( 'action' ) == 'render' ) {
1787                                 $url = $wgServer . $url;
1788                         }
1789                 }
1790                 Hooks::run( 'GetLocalURL', [ &$this, &$url, $query ] );
1791                 return $url;
1792         }
1793
1794         /**
1795          * Get a URL that's the simplest URL that will be valid to link, locally,
1796          * to the current Title.  It includes the fragment, but does not include
1797          * the server unless action=render is used (or the link is external).  If
1798          * there's a fragment but the prefixed text is empty, we just return a link
1799          * to the fragment.
1800          *
1801          * The result obviously should not be URL-escaped, but does need to be
1802          * HTML-escaped if it's being output in HTML.
1803          *
1804          * @param array $query
1805          * @param bool $query2
1806          * @param string $proto Protocol to use; setting this will cause a full URL to be used
1807          * @see self::getLocalURL for the arguments.
1808          * @return string The URL
1809          */
1810         public function getLinkURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1811                 if ( $this->isExternal() || $proto !== PROTO_RELATIVE ) {
1812                         $ret = $this->getFullURL( $query, $query2, $proto );
1813                 } elseif ( $this->getPrefixedText() === '' && $this->hasFragment() ) {
1814                         $ret = $this->getFragmentForURL();
1815                 } else {
1816                         $ret = $this->getLocalURL( $query, $query2 ) . $this->getFragmentForURL();
1817                 }
1818                 return $ret;
1819         }
1820
1821         /**
1822          * Get the URL form for an internal link.
1823          * - Used in various CDN-related code, in case we have a different
1824          * internal hostname for the server from the exposed one.
1825          *
1826          * This uses $wgInternalServer to qualify the path, or $wgServer
1827          * if $wgInternalServer is not set. If the server variable used is
1828          * protocol-relative, the URL will be expanded to http://
1829          *
1830          * @see self::getLocalURL for the arguments.
1831          * @return string The URL
1832          */
1833         public function getInternalURL( $query = '', $query2 = false ) {
1834                 global $wgInternalServer, $wgServer;
1835                 $query = self::fixUrlQueryArgs( $query, $query2 );
1836                 $server = $wgInternalServer !== false ? $wgInternalServer : $wgServer;
1837                 $url = wfExpandUrl( $server . $this->getLocalURL( $query ), PROTO_HTTP );
1838                 Hooks::run( 'GetInternalURL', [ &$this, &$url, $query ] );
1839                 return $url;
1840         }
1841
1842         /**
1843          * Get the URL for a canonical link, for use in things like IRC and
1844          * e-mail notifications. Uses $wgCanonicalServer and the
1845          * GetCanonicalURL hook.
1846          *
1847          * NOTE: Unlike getInternalURL(), the canonical URL includes the fragment
1848          *
1849          * @see self::getLocalURL for the arguments.
1850          * @return string The URL
1851          * @since 1.18
1852          */
1853         public function getCanonicalURL( $query = '', $query2 = false ) {
1854                 $query = self::fixUrlQueryArgs( $query, $query2 );
1855                 $url = wfExpandUrl( $this->getLocalURL( $query ) . $this->getFragmentForURL(), PROTO_CANONICAL );
1856                 Hooks::run( 'GetCanonicalURL', [ &$this, &$url, $query ] );
1857                 return $url;
1858         }
1859
1860         /**
1861          * Get the edit URL for this Title
1862          *
1863          * @return string The URL, or a null string if this is an interwiki link
1864          */
1865         public function getEditURL() {
1866                 if ( $this->isExternal() ) {
1867                         return '';
1868                 }
1869                 $s = $this->getLocalURL( 'action=edit' );
1870
1871                 return $s;
1872         }
1873
1874         /**
1875          * Can $user perform $action on this page?
1876          * This skips potentially expensive cascading permission checks
1877          * as well as avoids expensive error formatting
1878          *
1879          * Suitable for use for nonessential UI controls in common cases, but
1880          * _not_ for functional access control.
1881          *
1882          * May provide false positives, but should never provide a false negative.
1883          *
1884          * @param string $action Action that permission needs to be checked for
1885          * @param User $user User to check (since 1.19); $wgUser will be used if not provided.
1886          * @return bool
1887          */
1888         public function quickUserCan( $action, $user = null ) {
1889                 return $this->userCan( $action, $user, false );
1890         }
1891
1892         /**
1893          * Can $user perform $action on this page?
1894          *
1895          * @param string $action Action that permission needs to be checked for
1896          * @param User $user User to check (since 1.19); $wgUser will be used if not
1897          *   provided.
1898          * @param string $rigor Same format as Title::getUserPermissionsErrors()
1899          * @return bool
1900          */
1901         public function userCan( $action, $user = null, $rigor = 'secure' ) {
1902                 if ( !$user instanceof User ) {
1903                         global $wgUser;
1904                         $user = $wgUser;
1905                 }
1906
1907                 return !count( $this->getUserPermissionsErrorsInternal( $action, $user, $rigor, true ) );
1908         }
1909
1910         /**
1911          * Can $user perform $action on this page?
1912          *
1913          * @todo FIXME: This *does not* check throttles (User::pingLimiter()).
1914          *
1915          * @param string $action Action that permission needs to be checked for
1916          * @param User $user User to check
1917          * @param string $rigor One of (quick,full,secure)
1918          *   - quick  : does cheap permission checks from slaves (usable for GUI creation)
1919          *   - full   : does cheap and expensive checks possibly from a slave
1920          *   - secure : does cheap and expensive checks, using the master as needed
1921          * @param array $ignoreErrors Array of Strings Set this to a list of message keys
1922          *   whose corresponding errors may be ignored.
1923          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
1924          */
1925         public function getUserPermissionsErrors(
1926                 $action, $user, $rigor = 'secure', $ignoreErrors = []
1927         ) {
1928                 $errors = $this->getUserPermissionsErrorsInternal( $action, $user, $rigor );
1929
1930                 // Remove the errors being ignored.
1931                 foreach ( $errors as $index => $error ) {
1932                         $errKey = is_array( $error ) ? $error[0] : $error;
1933
1934                         if ( in_array( $errKey, $ignoreErrors ) ) {
1935                                 unset( $errors[$index] );
1936                         }
1937                         if ( $errKey instanceof MessageSpecifier && in_array( $errKey->getKey(), $ignoreErrors ) ) {
1938                                 unset( $errors[$index] );
1939                         }
1940                 }
1941
1942                 return $errors;
1943         }
1944
1945         /**
1946          * Permissions checks that fail most often, and which are easiest to test.
1947          *
1948          * @param string $action The action to check
1949          * @param User $user User to check
1950          * @param array $errors List of current errors
1951          * @param string $rigor Same format as Title::getUserPermissionsErrors()
1952          * @param bool $short Short circuit on first error
1953          *
1954          * @return array List of errors
1955          */
1956         private function checkQuickPermissions( $action, $user, $errors, $rigor, $short ) {
1957                 if ( !Hooks::run( 'TitleQuickPermissions',
1958                         [ $this, $user, $action, &$errors, ( $rigor !== 'quick' ), $short ] )
1959                 ) {
1960                         return $errors;
1961                 }
1962
1963                 if ( $action == 'create' ) {
1964                         if (
1965                                 ( $this->isTalkPage() && !$user->isAllowed( 'createtalk' ) ) ||
1966                                 ( !$this->isTalkPage() && !$user->isAllowed( 'createpage' ) )
1967                         ) {
1968                                 $errors[] = $user->isAnon() ? [ 'nocreatetext' ] : [ 'nocreate-loggedin' ];
1969                         }
1970                 } elseif ( $action == 'move' ) {
1971                         if ( !$user->isAllowed( 'move-rootuserpages' )
1972                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
1973                                 // Show user page-specific message only if the user can move other pages
1974                                 $errors[] = [ 'cant-move-user-page' ];
1975                         }
1976
1977                         // Check if user is allowed to move files if it's a file
1978                         if ( $this->mNamespace == NS_FILE && !$user->isAllowed( 'movefile' ) ) {
1979                                 $errors[] = [ 'movenotallowedfile' ];
1980                         }
1981
1982                         // Check if user is allowed to move category pages if it's a category page
1983                         if ( $this->mNamespace == NS_CATEGORY && !$user->isAllowed( 'move-categorypages' ) ) {
1984                                 $errors[] = [ 'cant-move-category-page' ];
1985                         }
1986
1987                         if ( !$user->isAllowed( 'move' ) ) {
1988                                 // User can't move anything
1989                                 $userCanMove = User::groupHasPermission( 'user', 'move' );
1990                                 $autoconfirmedCanMove = User::groupHasPermission( 'autoconfirmed', 'move' );
1991                                 if ( $user->isAnon() && ( $userCanMove || $autoconfirmedCanMove ) ) {
1992                                         // custom message if logged-in users without any special rights can move
1993                                         $errors[] = [ 'movenologintext' ];
1994                                 } else {
1995                                         $errors[] = [ 'movenotallowed' ];
1996                                 }
1997                         }
1998                 } elseif ( $action == 'move-target' ) {
1999                         if ( !$user->isAllowed( 'move' ) ) {
2000                                 // User can't move anything
2001                                 $errors[] = [ 'movenotallowed' ];
2002                         } elseif ( !$user->isAllowed( 'move-rootuserpages' )
2003                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
2004                                 // Show user page-specific message only if the user can move other pages
2005                                 $errors[] = [ 'cant-move-to-user-page' ];
2006                         } elseif ( !$user->isAllowed( 'move-categorypages' )
2007                                         && $this->mNamespace == NS_CATEGORY ) {
2008                                 // Show category page-specific message only if the user can move other pages
2009                                 $errors[] = [ 'cant-move-to-category-page' ];
2010                         }
2011                 } elseif ( !$user->isAllowed( $action ) ) {
2012                         $errors[] = $this->missingPermissionError( $action, $short );
2013                 }
2014
2015                 return $errors;
2016         }
2017
2018         /**
2019          * Add the resulting error code to the errors array
2020          *
2021          * @param array $errors List of current errors
2022          * @param array $result Result of errors
2023          *
2024          * @return array List of errors
2025          */
2026         private function resultToError( $errors, $result ) {
2027                 if ( is_array( $result ) && count( $result ) && !is_array( $result[0] ) ) {
2028                         // A single array representing an error
2029                         $errors[] = $result;
2030                 } elseif ( is_array( $result ) && is_array( $result[0] ) ) {
2031                         // A nested array representing multiple errors
2032                         $errors = array_merge( $errors, $result );
2033                 } elseif ( $result !== '' && is_string( $result ) ) {
2034                         // A string representing a message-id
2035                         $errors[] = [ $result ];
2036                 } elseif ( $result instanceof MessageSpecifier ) {
2037                         // A message specifier representing an error
2038                         $errors[] = [ $result ];
2039                 } elseif ( $result === false ) {
2040                         // a generic "We don't want them to do that"
2041                         $errors[] = [ 'badaccess-group0' ];
2042                 }
2043                 return $errors;
2044         }
2045
2046         /**
2047          * Check various permission hooks
2048          *
2049          * @param string $action The action to check
2050          * @param User $user User to check
2051          * @param array $errors List of current errors
2052          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2053          * @param bool $short Short circuit on first error
2054          *
2055          * @return array List of errors
2056          */
2057         private function checkPermissionHooks( $action, $user, $errors, $rigor, $short ) {
2058                 // Use getUserPermissionsErrors instead
2059                 $result = '';
2060                 if ( !Hooks::run( 'userCan', [ &$this, &$user, $action, &$result ] ) ) {
2061                         return $result ? [] : [ [ 'badaccess-group0' ] ];
2062                 }
2063                 // Check getUserPermissionsErrors hook
2064                 if ( !Hooks::run( 'getUserPermissionsErrors', [ &$this, &$user, $action, &$result ] ) ) {
2065                         $errors = $this->resultToError( $errors, $result );
2066                 }
2067                 // Check getUserPermissionsErrorsExpensive hook
2068                 if (
2069                         $rigor !== 'quick'
2070                         && !( $short && count( $errors ) > 0 )
2071                         && !Hooks::run( 'getUserPermissionsErrorsExpensive', [ &$this, &$user, $action, &$result ] )
2072                 ) {
2073                         $errors = $this->resultToError( $errors, $result );
2074                 }
2075
2076                 return $errors;
2077         }
2078
2079         /**
2080          * Check permissions on special pages & namespaces
2081          *
2082          * @param string $action The action to check
2083          * @param User $user User to check
2084          * @param array $errors List of current errors
2085          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2086          * @param bool $short Short circuit on first error
2087          *
2088          * @return array List of errors
2089          */
2090         private function checkSpecialsAndNSPermissions( $action, $user, $errors, $rigor, $short ) {
2091                 # Only 'createaccount' can be performed on special pages,
2092                 # which don't actually exist in the DB.
2093                 if ( NS_SPECIAL == $this->mNamespace && $action !== 'createaccount' ) {
2094                         $errors[] = [ 'ns-specialprotected' ];
2095                 }
2096
2097                 # Check $wgNamespaceProtection for restricted namespaces
2098                 if ( $this->isNamespaceProtected( $user ) ) {
2099                         $ns = $this->mNamespace == NS_MAIN ?
2100                                 wfMessage( 'nstab-main' )->text() : $this->getNsText();
2101                         $errors[] = $this->mNamespace == NS_MEDIAWIKI ?
2102                                 [ 'protectedinterface', $action ] : [ 'namespaceprotected', $ns, $action ];
2103                 }
2104
2105                 return $errors;
2106         }
2107
2108         /**
2109          * Check CSS/JS sub-page permissions
2110          *
2111          * @param string $action The action to check
2112          * @param User $user User to check
2113          * @param array $errors List of current errors
2114          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2115          * @param bool $short Short circuit on first error
2116          *
2117          * @return array List of errors
2118          */
2119         private function checkCSSandJSPermissions( $action, $user, $errors, $rigor, $short ) {
2120                 # Protect css/js subpages of user pages
2121                 # XXX: this might be better using restrictions
2122                 # XXX: right 'editusercssjs' is deprecated, for backward compatibility only
2123                 if ( $action != 'patrol' && !$user->isAllowed( 'editusercssjs' ) ) {
2124                         if ( preg_match( '/^' . preg_quote( $user->getName(), '/' ) . '\//', $this->mTextform ) ) {
2125                                 if ( $this->isCssSubpage() && !$user->isAllowedAny( 'editmyusercss', 'editusercss' ) ) {
2126                                         $errors[] = [ 'mycustomcssprotected', $action ];
2127                                 } elseif ( $this->isJsSubpage() && !$user->isAllowedAny( 'editmyuserjs', 'edituserjs' ) ) {
2128                                         $errors[] = [ 'mycustomjsprotected', $action ];
2129                                 }
2130                         } else {
2131                                 if ( $this->isCssSubpage() && !$user->isAllowed( 'editusercss' ) ) {
2132                                         $errors[] = [ 'customcssprotected', $action ];
2133                                 } elseif ( $this->isJsSubpage() && !$user->isAllowed( 'edituserjs' ) ) {
2134                                         $errors[] = [ 'customjsprotected', $action ];
2135                                 }
2136                         }
2137                 }
2138
2139                 return $errors;
2140         }
2141
2142         /**
2143          * Check against page_restrictions table requirements on this
2144          * page. The user must possess all required rights for this
2145          * action.
2146          *
2147          * @param string $action The action to check
2148          * @param User $user User to check
2149          * @param array $errors List of current errors
2150          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2151          * @param bool $short Short circuit on first error
2152          *
2153          * @return array List of errors
2154          */
2155         private function checkPageRestrictions( $action, $user, $errors, $rigor, $short ) {
2156                 foreach ( $this->getRestrictions( $action ) as $right ) {
2157                         // Backwards compatibility, rewrite sysop -> editprotected
2158                         if ( $right == 'sysop' ) {
2159                                 $right = 'editprotected';
2160                         }
2161                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2162                         if ( $right == 'autoconfirmed' ) {
2163                                 $right = 'editsemiprotected';
2164                         }
2165                         if ( $right == '' ) {
2166                                 continue;
2167                         }
2168                         if ( !$user->isAllowed( $right ) ) {
2169                                 $errors[] = [ 'protectedpagetext', $right, $action ];
2170                         } elseif ( $this->mCascadeRestriction && !$user->isAllowed( 'protect' ) ) {
2171                                 $errors[] = [ 'protectedpagetext', 'protect', $action ];
2172                         }
2173                 }
2174
2175                 return $errors;
2176         }
2177
2178         /**
2179          * Check restrictions on cascading pages.
2180          *
2181          * @param string $action The action to check
2182          * @param User $user User to check
2183          * @param array $errors List of current errors
2184          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2185          * @param bool $short Short circuit on first error
2186          *
2187          * @return array List of errors
2188          */
2189         private function checkCascadingSourcesRestrictions( $action, $user, $errors, $rigor, $short ) {
2190                 if ( $rigor !== 'quick' && !$this->isCssJsSubpage() ) {
2191                         # We /could/ use the protection level on the source page, but it's
2192                         # fairly ugly as we have to establish a precedence hierarchy for pages
2193                         # included by multiple cascade-protected pages. So just restrict
2194                         # it to people with 'protect' permission, as they could remove the
2195                         # protection anyway.
2196                         list( $cascadingSources, $restrictions ) = $this->getCascadeProtectionSources();
2197                         # Cascading protection depends on more than this page...
2198                         # Several cascading protected pages may include this page...
2199                         # Check each cascading level
2200                         # This is only for protection restrictions, not for all actions
2201                         if ( isset( $restrictions[$action] ) ) {
2202                                 foreach ( $restrictions[$action] as $right ) {
2203                                         // Backwards compatibility, rewrite sysop -> editprotected
2204                                         if ( $right == 'sysop' ) {
2205                                                 $right = 'editprotected';
2206                                         }
2207                                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2208                                         if ( $right == 'autoconfirmed' ) {
2209                                                 $right = 'editsemiprotected';
2210                                         }
2211                                         if ( $right != '' && !$user->isAllowedAll( 'protect', $right ) ) {
2212                                                 $pages = '';
2213                                                 foreach ( $cascadingSources as $page ) {
2214                                                         $pages .= '* [[:' . $page->getPrefixedText() . "]]\n";
2215                                                 }
2216                                                 $errors[] = [ 'cascadeprotected', count( $cascadingSources ), $pages, $action ];
2217                                         }
2218                                 }
2219                         }
2220                 }
2221
2222                 return $errors;
2223         }
2224
2225         /**
2226          * Check action permissions not already checked in checkQuickPermissions
2227          *
2228          * @param string $action The action to check
2229          * @param User $user User to check
2230          * @param array $errors List of current errors
2231          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2232          * @param bool $short Short circuit on first error
2233          *
2234          * @return array List of errors
2235          */
2236         private function checkActionPermissions( $action, $user, $errors, $rigor, $short ) {
2237                 global $wgDeleteRevisionsLimit, $wgLang;
2238
2239                 if ( $action == 'protect' ) {
2240                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit', $user, $rigor, true ) ) ) {
2241                                 // If they can't edit, they shouldn't protect.
2242                                 $errors[] = [ 'protect-cantedit' ];
2243                         }
2244                 } elseif ( $action == 'create' ) {
2245                         $title_protection = $this->getTitleProtection();
2246                         if ( $title_protection ) {
2247                                 if ( $title_protection['permission'] == ''
2248                                         || !$user->isAllowed( $title_protection['permission'] )
2249                                 ) {
2250                                         $errors[] = [
2251                                                 'titleprotected',
2252                                                 User::whoIs( $title_protection['user'] ),
2253                                                 $title_protection['reason']
2254                                         ];
2255                                 }
2256                         }
2257                 } elseif ( $action == 'move' ) {
2258                         // Check for immobile pages
2259                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2260                                 // Specific message for this case
2261                                 $errors[] = [ 'immobile-source-namespace', $this->getNsText() ];
2262                         } elseif ( !$this->isMovable() ) {
2263                                 // Less specific message for rarer cases
2264                                 $errors[] = [ 'immobile-source-page' ];
2265                         }
2266                 } elseif ( $action == 'move-target' ) {
2267                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2268                                 $errors[] = [ 'immobile-target-namespace', $this->getNsText() ];
2269                         } elseif ( !$this->isMovable() ) {
2270                                 $errors[] = [ 'immobile-target-page' ];
2271                         }
2272                 } elseif ( $action == 'delete' ) {
2273                         $tempErrors = $this->checkPageRestrictions( 'edit', $user, [], $rigor, true );
2274                         if ( !$tempErrors ) {
2275                                 $tempErrors = $this->checkCascadingSourcesRestrictions( 'edit',
2276                                         $user, $tempErrors, $rigor, true );
2277                         }
2278                         if ( $tempErrors ) {
2279                                 // If protection keeps them from editing, they shouldn't be able to delete.
2280                                 $errors[] = [ 'deleteprotected' ];
2281                         }
2282                         if ( $rigor !== 'quick' && $wgDeleteRevisionsLimit
2283                                 && !$this->userCan( 'bigdelete', $user ) && $this->isBigDeletion()
2284                         ) {
2285                                 $errors[] = [ 'delete-toobig', $wgLang->formatNum( $wgDeleteRevisionsLimit ) ];
2286                         }
2287                 }
2288                 return $errors;
2289         }
2290
2291         /**
2292          * Check that the user isn't blocked from editing.
2293          *
2294          * @param string $action The action to check
2295          * @param User $user User to check
2296          * @param array $errors List of current errors
2297          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2298          * @param bool $short Short circuit on first error
2299          *
2300          * @return array List of errors
2301          */
2302         private function checkUserBlock( $action, $user, $errors, $rigor, $short ) {
2303                 // Account creation blocks handled at userlogin.
2304                 // Unblocking handled in SpecialUnblock
2305                 if ( $rigor === 'quick' || in_array( $action, [ 'createaccount', 'unblock' ] ) ) {
2306                         return $errors;
2307                 }
2308
2309                 global $wgEmailConfirmToEdit;
2310
2311                 if ( $wgEmailConfirmToEdit && !$user->isEmailConfirmed() ) {
2312                         $errors[] = [ 'confirmedittext' ];
2313                 }
2314
2315                 $useSlave = ( $rigor !== 'secure' );
2316                 if ( ( $action == 'edit' || $action == 'create' )
2317                         && !$user->isBlockedFrom( $this, $useSlave )
2318                 ) {
2319                         // Don't block the user from editing their own talk page unless they've been
2320                         // explicitly blocked from that too.
2321                 } elseif ( $user->isBlocked() && $user->getBlock()->prevents( $action ) !== false ) {
2322                         // @todo FIXME: Pass the relevant context into this function.
2323                         $errors[] = $user->getBlock()->getPermissionsError( RequestContext::getMain() );
2324                 }
2325
2326                 return $errors;
2327         }
2328
2329         /**
2330          * Check that the user is allowed to read this page.
2331          *
2332          * @param string $action The action to check
2333          * @param User $user User to check
2334          * @param array $errors List of current errors
2335          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2336          * @param bool $short Short circuit on first error
2337          *
2338          * @return array List of errors
2339          */
2340         private function checkReadPermissions( $action, $user, $errors, $rigor, $short ) {
2341                 global $wgWhitelistRead, $wgWhitelistReadRegexp;
2342
2343                 $whitelisted = false;
2344                 if ( User::isEveryoneAllowed( 'read' ) ) {
2345                         # Shortcut for public wikis, allows skipping quite a bit of code
2346                         $whitelisted = true;
2347                 } elseif ( $user->isAllowed( 'read' ) ) {
2348                         # If the user is allowed to read pages, he is allowed to read all pages
2349                         $whitelisted = true;
2350                 } elseif ( $this->isSpecial( 'Userlogin' )
2351                         || $this->isSpecial( 'ChangePassword' )
2352                         || $this->isSpecial( 'PasswordReset' )
2353                 ) {
2354                         # Always grant access to the login page.
2355                         # Even anons need to be able to log in.
2356                         $whitelisted = true;
2357                 } elseif ( is_array( $wgWhitelistRead ) && count( $wgWhitelistRead ) ) {
2358                         # Time to check the whitelist
2359                         # Only do these checks is there's something to check against
2360                         $name = $this->getPrefixedText();
2361                         $dbName = $this->getPrefixedDBkey();
2362
2363                         // Check for explicit whitelisting with and without underscores
2364                         if ( in_array( $name, $wgWhitelistRead, true ) || in_array( $dbName, $wgWhitelistRead, true ) ) {
2365                                 $whitelisted = true;
2366                         } elseif ( $this->getNamespace() == NS_MAIN ) {
2367                                 # Old settings might have the title prefixed with
2368                                 # a colon for main-namespace pages
2369                                 if ( in_array( ':' . $name, $wgWhitelistRead ) ) {
2370                                         $whitelisted = true;
2371                                 }
2372                         } elseif ( $this->isSpecialPage() ) {
2373                                 # If it's a special page, ditch the subpage bit and check again
2374                                 $name = $this->getDBkey();
2375                                 list( $name, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $name );
2376                                 if ( $name ) {
2377                                         $pure = SpecialPage::getTitleFor( $name )->getPrefixedText();
2378                                         if ( in_array( $pure, $wgWhitelistRead, true ) ) {
2379                                                 $whitelisted = true;
2380                                         }
2381                                 }
2382                         }
2383                 }
2384
2385                 if ( !$whitelisted && is_array( $wgWhitelistReadRegexp ) && !empty( $wgWhitelistReadRegexp ) ) {
2386                         $name = $this->getPrefixedText();
2387                         // Check for regex whitelisting
2388                         foreach ( $wgWhitelistReadRegexp as $listItem ) {
2389                                 if ( preg_match( $listItem, $name ) ) {
2390                                         $whitelisted = true;
2391                                         break;
2392                                 }
2393                         }
2394                 }
2395
2396                 if ( !$whitelisted ) {
2397                         # If the title is not whitelisted, give extensions a chance to do so...
2398                         Hooks::run( 'TitleReadWhitelist', [ $this, $user, &$whitelisted ] );
2399                         if ( !$whitelisted ) {
2400                                 $errors[] = $this->missingPermissionError( $action, $short );
2401                         }
2402                 }
2403
2404                 return $errors;
2405         }
2406
2407         /**
2408          * Get a description array when the user doesn't have the right to perform
2409          * $action (i.e. when User::isAllowed() returns false)
2410          *
2411          * @param string $action The action to check
2412          * @param bool $short Short circuit on first error
2413          * @return array List of errors
2414          */
2415         private function missingPermissionError( $action, $short ) {
2416                 // We avoid expensive display logic for quickUserCan's and such
2417                 if ( $short ) {
2418                         return [ 'badaccess-group0' ];
2419                 }
2420
2421                 $groups = array_map( [ 'User', 'makeGroupLinkWiki' ],
2422                         User::getGroupsWithPermission( $action ) );
2423
2424                 if ( count( $groups ) ) {
2425                         global $wgLang;
2426                         return [
2427                                 'badaccess-groups',
2428                                 $wgLang->commaList( $groups ),
2429                                 count( $groups )
2430                         ];
2431                 } else {
2432                         return [ 'badaccess-group0' ];
2433                 }
2434         }
2435
2436         /**
2437          * Can $user perform $action on this page? This is an internal function,
2438          * with multiple levels of checks depending on performance needs; see $rigor below.
2439          * It does not check wfReadOnly().
2440          *
2441          * @param string $action Action that permission needs to be checked for
2442          * @param User $user User to check
2443          * @param string $rigor One of (quick,full,secure)
2444          *   - quick  : does cheap permission checks from slaves (usable for GUI creation)
2445          *   - full   : does cheap and expensive checks possibly from a slave
2446          *   - secure : does cheap and expensive checks, using the master as needed
2447          * @param bool $short Set this to true to stop after the first permission error.
2448          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
2449          */
2450         protected function getUserPermissionsErrorsInternal(
2451                 $action, $user, $rigor = 'secure', $short = false
2452         ) {
2453                 if ( $rigor === true ) {
2454                         $rigor = 'secure'; // b/c
2455                 } elseif ( $rigor === false ) {
2456                         $rigor = 'quick'; // b/c
2457                 } elseif ( !in_array( $rigor, [ 'quick', 'full', 'secure' ] ) ) {
2458                         throw new Exception( "Invalid rigor parameter '$rigor'." );
2459                 }
2460
2461                 # Read has special handling
2462                 if ( $action == 'read' ) {
2463                         $checks = [
2464                                 'checkPermissionHooks',
2465                                 'checkReadPermissions',
2466                         ];
2467                 # Don't call checkSpecialsAndNSPermissions or checkCSSandJSPermissions
2468                 # here as it will lead to duplicate error messages. This is okay to do
2469                 # since anywhere that checks for create will also check for edit, and
2470                 # those checks are called for edit.
2471                 } elseif ( $action == 'create' ) {
2472                         $checks = [
2473                                 'checkQuickPermissions',
2474                                 'checkPermissionHooks',
2475                                 'checkPageRestrictions',
2476                                 'checkCascadingSourcesRestrictions',
2477                                 'checkActionPermissions',
2478                                 'checkUserBlock'
2479                         ];
2480                 } else {
2481                         $checks = [
2482                                 'checkQuickPermissions',
2483                                 'checkPermissionHooks',
2484                                 'checkSpecialsAndNSPermissions',
2485                                 'checkCSSandJSPermissions',
2486                                 'checkPageRestrictions',
2487                                 'checkCascadingSourcesRestrictions',
2488                                 'checkActionPermissions',
2489                                 'checkUserBlock'
2490                         ];
2491                 }
2492
2493                 $errors = [];
2494                 while ( count( $checks ) > 0 &&
2495                                 !( $short && count( $errors ) > 0 ) ) {
2496                         $method = array_shift( $checks );
2497                         $errors = $this->$method( $action, $user, $errors, $rigor, $short );
2498                 }
2499
2500                 return $errors;
2501         }
2502
2503         /**
2504          * Get a filtered list of all restriction types supported by this wiki.
2505          * @param bool $exists True to get all restriction types that apply to
2506          * titles that do exist, False for all restriction types that apply to
2507          * titles that do not exist
2508          * @return array
2509          */
2510         public static function getFilteredRestrictionTypes( $exists = true ) {
2511                 global $wgRestrictionTypes;
2512                 $types = $wgRestrictionTypes;
2513                 if ( $exists ) {
2514                         # Remove the create restriction for existing titles
2515                         $types = array_diff( $types, [ 'create' ] );
2516                 } else {
2517                         # Only the create and upload restrictions apply to non-existing titles
2518                         $types = array_intersect( $types, [ 'create', 'upload' ] );
2519                 }
2520                 return $types;
2521         }
2522
2523         /**
2524          * Returns restriction types for the current Title
2525          *
2526          * @return array Applicable restriction types
2527          */
2528         public function getRestrictionTypes() {
2529                 if ( $this->isSpecialPage() ) {
2530                         return [];
2531                 }
2532
2533                 $types = self::getFilteredRestrictionTypes( $this->exists() );
2534
2535                 if ( $this->getNamespace() != NS_FILE ) {
2536                         # Remove the upload restriction for non-file titles
2537                         $types = array_diff( $types, [ 'upload' ] );
2538                 }
2539
2540                 Hooks::run( 'TitleGetRestrictionTypes', [ $this, &$types ] );
2541
2542                 wfDebug( __METHOD__ . ': applicable restrictions to [[' .
2543                         $this->getPrefixedText() . ']] are {' . implode( ',', $types ) . "}\n" );
2544
2545                 return $types;
2546         }
2547
2548         /**
2549          * Is this title subject to title protection?
2550          * Title protection is the one applied against creation of such title.
2551          *
2552          * @return array|bool An associative array representing any existent title
2553          *   protection, or false if there's none.
2554          */
2555         public function getTitleProtection() {
2556                 // Can't protect pages in special namespaces
2557                 if ( $this->getNamespace() < 0 ) {
2558                         return false;
2559                 }
2560
2561                 // Can't protect pages that exist.
2562                 if ( $this->exists() ) {
2563                         return false;
2564                 }
2565
2566                 if ( $this->mTitleProtection === null ) {
2567                         $dbr = wfGetDB( DB_SLAVE );
2568                         $res = $dbr->select(
2569                                 'protected_titles',
2570                                 [
2571                                         'user' => 'pt_user',
2572                                         'reason' => 'pt_reason',
2573                                         'expiry' => 'pt_expiry',
2574                                         'permission' => 'pt_create_perm'
2575                                 ],
2576                                 [ 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ],
2577                                 __METHOD__
2578                         );
2579
2580                         // fetchRow returns false if there are no rows.
2581                         $row = $dbr->fetchRow( $res );
2582                         if ( $row ) {
2583                                 if ( $row['permission'] == 'sysop' ) {
2584                                         $row['permission'] = 'editprotected'; // B/C
2585                                 }
2586                                 if ( $row['permission'] == 'autoconfirmed' ) {
2587                                         $row['permission'] = 'editsemiprotected'; // B/C
2588                                 }
2589                                 $row['expiry'] = $dbr->decodeExpiry( $row['expiry'] );
2590                         }
2591                         $this->mTitleProtection = $row;
2592                 }
2593                 return $this->mTitleProtection;
2594         }
2595
2596         /**
2597          * Remove any title protection due to page existing
2598          */
2599         public function deleteTitleProtection() {
2600                 $dbw = wfGetDB( DB_MASTER );
2601
2602                 $dbw->delete(
2603                         'protected_titles',
2604                         [ 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ],
2605                         __METHOD__
2606                 );
2607                 $this->mTitleProtection = false;
2608         }
2609
2610         /**
2611          * Is this page "semi-protected" - the *only* protection levels are listed
2612          * in $wgSemiprotectedRestrictionLevels?
2613          *
2614          * @param string $action Action to check (default: edit)
2615          * @return bool
2616          */
2617         public function isSemiProtected( $action = 'edit' ) {
2618                 global $wgSemiprotectedRestrictionLevels;
2619
2620                 $restrictions = $this->getRestrictions( $action );
2621                 $semi = $wgSemiprotectedRestrictionLevels;
2622                 if ( !$restrictions || !$semi ) {
2623                         // Not protected, or all protection is full protection
2624                         return false;
2625                 }
2626
2627                 // Remap autoconfirmed to editsemiprotected for BC
2628                 foreach ( array_keys( $semi, 'autoconfirmed' ) as $key ) {
2629                         $semi[$key] = 'editsemiprotected';
2630                 }
2631                 foreach ( array_keys( $restrictions, 'autoconfirmed' ) as $key ) {
2632                         $restrictions[$key] = 'editsemiprotected';
2633                 }
2634
2635                 return !array_diff( $restrictions, $semi );
2636         }
2637
2638         /**
2639          * Does the title correspond to a protected article?
2640          *
2641          * @param string $action The action the page is protected from,
2642          * by default checks all actions.
2643          * @return bool
2644          */
2645         public function isProtected( $action = '' ) {
2646                 global $wgRestrictionLevels;
2647
2648                 $restrictionTypes = $this->getRestrictionTypes();
2649
2650                 # Special pages have inherent protection
2651                 if ( $this->isSpecialPage() ) {
2652                         return true;
2653                 }
2654
2655                 # Check regular protection levels
2656                 foreach ( $restrictionTypes as $type ) {
2657                         if ( $action == $type || $action == '' ) {
2658                                 $r = $this->getRestrictions( $type );
2659                                 foreach ( $wgRestrictionLevels as $level ) {
2660                                         if ( in_array( $level, $r ) && $level != '' ) {
2661                                                 return true;
2662                                         }
2663                                 }
2664                         }
2665                 }
2666
2667                 return false;
2668         }
2669
2670         /**
2671          * Determines if $user is unable to edit this page because it has been protected
2672          * by $wgNamespaceProtection.
2673          *
2674          * @param User $user User object to check permissions
2675          * @return bool
2676          */
2677         public function isNamespaceProtected( User $user ) {
2678                 global $wgNamespaceProtection;
2679
2680                 if ( isset( $wgNamespaceProtection[$this->mNamespace] ) ) {
2681                         foreach ( (array)$wgNamespaceProtection[$this->mNamespace] as $right ) {
2682                                 if ( $right != '' && !$user->isAllowed( $right ) ) {
2683                                         return true;
2684                                 }
2685                         }
2686                 }
2687                 return false;
2688         }
2689
2690         /**
2691          * Cascading protection: Return true if cascading restrictions apply to this page, false if not.
2692          *
2693          * @return bool If the page is subject to cascading restrictions.
2694          */
2695         public function isCascadeProtected() {
2696                 list( $sources, /* $restrictions */ ) = $this->getCascadeProtectionSources( false );
2697                 return ( $sources > 0 );
2698         }
2699
2700         /**
2701          * Determines whether cascading protection sources have already been loaded from
2702          * the database.
2703          *
2704          * @param bool $getPages True to check if the pages are loaded, or false to check
2705          * if the status is loaded.
2706          * @return bool Whether or not the specified information has been loaded
2707          * @since 1.23
2708          */
2709         public function areCascadeProtectionSourcesLoaded( $getPages = true ) {
2710                 return $getPages ? $this->mCascadeSources !== null : $this->mHasCascadingRestrictions !== null;
2711         }
2712
2713         /**
2714          * Cascading protection: Get the source of any cascading restrictions on this page.
2715          *
2716          * @param bool $getPages Whether or not to retrieve the actual pages
2717          *        that the restrictions have come from and the actual restrictions
2718          *        themselves.
2719          * @return array Two elements: First is an array of Title objects of the
2720          *        pages from which cascading restrictions have come, false for
2721          *        none, or true if such restrictions exist but $getPages was not
2722          *        set. Second is an array like that returned by
2723          *        Title::getAllRestrictions(), or an empty array if $getPages is
2724          *        false.
2725          */
2726         public function getCascadeProtectionSources( $getPages = true ) {
2727                 $pagerestrictions = [];
2728
2729                 if ( $this->mCascadeSources !== null && $getPages ) {
2730                         return [ $this->mCascadeSources, $this->mCascadingRestrictions ];
2731                 } elseif ( $this->mHasCascadingRestrictions !== null && !$getPages ) {
2732                         return [ $this->mHasCascadingRestrictions, $pagerestrictions ];
2733                 }
2734
2735                 $dbr = wfGetDB( DB_SLAVE );
2736
2737                 if ( $this->getNamespace() == NS_FILE ) {
2738                         $tables = [ 'imagelinks', 'page_restrictions' ];
2739                         $where_clauses = [
2740                                 'il_to' => $this->getDBkey(),
2741                                 'il_from=pr_page',
2742                                 'pr_cascade' => 1
2743                         ];
2744                 } else {
2745                         $tables = [ 'templatelinks', 'page_restrictions' ];
2746                         $where_clauses = [
2747                                 'tl_namespace' => $this->getNamespace(),
2748                                 'tl_title' => $this->getDBkey(),
2749                                 'tl_from=pr_page',
2750                                 'pr_cascade' => 1
2751                         ];
2752                 }
2753
2754                 if ( $getPages ) {
2755                         $cols = [ 'pr_page', 'page_namespace', 'page_title',
2756                                 'pr_expiry', 'pr_type', 'pr_level' ];
2757                         $where_clauses[] = 'page_id=pr_page';
2758                         $tables[] = 'page';
2759                 } else {
2760                         $cols = [ 'pr_expiry' ];
2761                 }
2762
2763                 $res = $dbr->select( $tables, $cols, $where_clauses, __METHOD__ );
2764
2765                 $sources = $getPages ? [] : false;
2766                 $now = wfTimestampNow();
2767
2768                 foreach ( $res as $row ) {
2769                         $expiry = $dbr->decodeExpiry( $row->pr_expiry );
2770                         if ( $expiry > $now ) {
2771                                 if ( $getPages ) {
2772                                         $page_id = $row->pr_page;
2773                                         $page_ns = $row->page_namespace;
2774                                         $page_title = $row->page_title;
2775                                         $sources[$page_id] = Title::makeTitle( $page_ns, $page_title );
2776                                         # Add groups needed for each restriction type if its not already there
2777                                         # Make sure this restriction type still exists
2778
2779                                         if ( !isset( $pagerestrictions[$row->pr_type] ) ) {
2780                                                 $pagerestrictions[$row->pr_type] = [];
2781                                         }
2782
2783                                         if (
2784                                                 isset( $pagerestrictions[$row->pr_type] )
2785                                                 && !in_array( $row->pr_level, $pagerestrictions[$row->pr_type] )
2786                                         ) {
2787                                                 $pagerestrictions[$row->pr_type][] = $row->pr_level;
2788                                         }
2789                                 } else {
2790                                         $sources = true;
2791                                 }
2792                         }
2793                 }
2794
2795                 if ( $getPages ) {
2796                         $this->mCascadeSources = $sources;
2797                         $this->mCascadingRestrictions = $pagerestrictions;
2798                 } else {
2799                         $this->mHasCascadingRestrictions = $sources;
2800                 }
2801
2802                 return [ $sources, $pagerestrictions ];
2803         }
2804
2805         /**
2806          * Accessor for mRestrictionsLoaded
2807          *
2808          * @return bool Whether or not the page's restrictions have already been
2809          * loaded from the database
2810          * @since 1.23
2811          */
2812         public function areRestrictionsLoaded() {
2813                 return $this->mRestrictionsLoaded;
2814         }
2815
2816         /**
2817          * Accessor/initialisation for mRestrictions
2818          *
2819          * @param string $action Action that permission needs to be checked for
2820          * @return array Restriction levels needed to take the action. All levels are
2821          *     required. Note that restriction levels are normally user rights, but 'sysop'
2822          *     and 'autoconfirmed' are also allowed for backwards compatibility. These should
2823          *     be mapped to 'editprotected' and 'editsemiprotected' respectively.
2824          */
2825         public function getRestrictions( $action ) {
2826                 if ( !$this->mRestrictionsLoaded ) {
2827                         $this->loadRestrictions();
2828                 }
2829                 return isset( $this->mRestrictions[$action] )
2830                                 ? $this->mRestrictions[$action]
2831                                 : [];
2832         }
2833
2834         /**
2835          * Accessor/initialisation for mRestrictions
2836          *
2837          * @return array Keys are actions, values are arrays as returned by
2838          *     Title::getRestrictions()
2839          * @since 1.23
2840          */
2841         public function getAllRestrictions() {
2842                 if ( !$this->mRestrictionsLoaded ) {
2843                         $this->loadRestrictions();
2844                 }
2845                 return $this->mRestrictions;
2846         }
2847
2848         /**
2849          * Get the expiry time for the restriction against a given action
2850          *
2851          * @param string $action
2852          * @return string|bool 14-char timestamp, or 'infinity' if the page is protected forever
2853          *     or not protected at all, or false if the action is not recognised.
2854          */
2855         public function getRestrictionExpiry( $action ) {
2856                 if ( !$this->mRestrictionsLoaded ) {
2857                         $this->loadRestrictions();
2858                 }
2859                 return isset( $this->mRestrictionsExpiry[$action] ) ? $this->mRestrictionsExpiry[$action] : false;
2860         }
2861
2862         /**
2863          * Returns cascading restrictions for the current article
2864          *
2865          * @return bool
2866          */
2867         function areRestrictionsCascading() {
2868                 if ( !$this->mRestrictionsLoaded ) {
2869                         $this->loadRestrictions();
2870                 }
2871
2872                 return $this->mCascadeRestriction;
2873         }
2874
2875         /**
2876          * Loads a string into mRestrictions array
2877          *
2878          * @param ResultWrapper $res Resource restrictions as an SQL result.
2879          * @param string $oldFashionedRestrictions Comma-separated list of page
2880          *        restrictions from page table (pre 1.10)
2881          */
2882         private function loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions = null ) {
2883                 $rows = [];
2884
2885                 foreach ( $res as $row ) {
2886                         $rows[] = $row;
2887                 }
2888
2889                 $this->loadRestrictionsFromRows( $rows, $oldFashionedRestrictions );
2890         }
2891
2892         /**
2893          * Compiles list of active page restrictions from both page table (pre 1.10)
2894          * and page_restrictions table for this existing page.
2895          * Public for usage by LiquidThreads.
2896          *
2897          * @param array $rows Array of db result objects
2898          * @param string $oldFashionedRestrictions Comma-separated list of page
2899          *   restrictions from page table (pre 1.10)
2900          */
2901         public function loadRestrictionsFromRows( $rows, $oldFashionedRestrictions = null ) {
2902                 $dbr = wfGetDB( DB_SLAVE );
2903
2904                 $restrictionTypes = $this->getRestrictionTypes();
2905
2906                 foreach ( $restrictionTypes as $type ) {
2907                         $this->mRestrictions[$type] = [];
2908                         $this->mRestrictionsExpiry[$type] = 'infinity';
2909                 }
2910
2911                 $this->mCascadeRestriction = false;
2912
2913                 # Backwards-compatibility: also load the restrictions from the page record (old format).
2914                 if ( $oldFashionedRestrictions !== null ) {
2915                         $this->mOldRestrictions = $oldFashionedRestrictions;
2916                 }
2917
2918                 if ( $this->mOldRestrictions === false ) {
2919                         $this->mOldRestrictions = $dbr->selectField( 'page', 'page_restrictions',
2920                                 [ 'page_id' => $this->getArticleID() ], __METHOD__ );
2921                 }
2922
2923                 if ( $this->mOldRestrictions != '' ) {
2924                         foreach ( explode( ':', trim( $this->mOldRestrictions ) ) as $restrict ) {
2925                                 $temp = explode( '=', trim( $restrict ) );
2926                                 if ( count( $temp ) == 1 ) {
2927                                         // old old format should be treated as edit/move restriction
2928                                         $this->mRestrictions['edit'] = explode( ',', trim( $temp[0] ) );
2929                                         $this->mRestrictions['move'] = explode( ',', trim( $temp[0] ) );
2930                                 } else {
2931                                         $restriction = trim( $temp[1] );
2932                                         if ( $restriction != '' ) { // some old entries are empty
2933                                                 $this->mRestrictions[$temp[0]] = explode( ',', $restriction );
2934                                         }
2935                                 }
2936                         }
2937                 }
2938
2939                 if ( count( $rows ) ) {
2940                         # Current system - load second to make them override.
2941                         $now = wfTimestampNow();
2942
2943                         # Cycle through all the restrictions.
2944                         foreach ( $rows as $row ) {
2945
2946                                 // Don't take care of restrictions types that aren't allowed
2947                                 if ( !in_array( $row->pr_type, $restrictionTypes ) ) {
2948                                         continue;
2949                                 }
2950
2951                                 // This code should be refactored, now that it's being used more generally,
2952                                 // But I don't really see any harm in leaving it in Block for now -werdna
2953                                 $expiry = $dbr->decodeExpiry( $row->pr_expiry );
2954
2955                                 // Only apply the restrictions if they haven't expired!
2956                                 if ( !$expiry || $expiry > $now ) {
2957                                         $this->mRestrictionsExpiry[$row->pr_type] = $expiry;
2958                                         $this->mRestrictions[$row->pr_type] = explode( ',', trim( $row->pr_level ) );
2959
2960                                         $this->mCascadeRestriction |= $row->pr_cascade;
2961                                 }
2962                         }
2963                 }
2964
2965                 $this->mRestrictionsLoaded = true;
2966         }
2967
2968         /**
2969          * Load restrictions from the page_restrictions table
2970          *
2971          * @param string $oldFashionedRestrictions Comma-separated list of page
2972          *   restrictions from page table (pre 1.10)
2973          */
2974         public function loadRestrictions( $oldFashionedRestrictions = null ) {
2975                 if ( !$this->mRestrictionsLoaded ) {
2976                         $dbr = wfGetDB( DB_SLAVE );
2977                         if ( $this->exists() ) {
2978                                 $res = $dbr->select(
2979                                         'page_restrictions',
2980                                         [ 'pr_type', 'pr_expiry', 'pr_level', 'pr_cascade' ],
2981                                         [ 'pr_page' => $this->getArticleID() ],
2982                                         __METHOD__
2983                                 );
2984
2985                                 $this->loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions );
2986                         } else {
2987                                 $title_protection = $this->getTitleProtection();
2988
2989                                 if ( $title_protection ) {
2990                                         $now = wfTimestampNow();
2991                                         $expiry = $dbr->decodeExpiry( $title_protection['expiry'] );
2992
2993                                         if ( !$expiry || $expiry > $now ) {
2994                                                 // Apply the restrictions
2995                                                 $this->mRestrictionsExpiry['create'] = $expiry;
2996                                                 $this->mRestrictions['create'] = explode( ',', trim( $title_protection['permission'] ) );
2997                                         } else { // Get rid of the old restrictions
2998                                                 $this->mTitleProtection = false;
2999                                         }
3000                                 } else {
3001                                         $this->mRestrictionsExpiry['create'] = 'infinity';
3002                                 }
3003                                 $this->mRestrictionsLoaded = true;
3004                         }
3005                 }
3006         }
3007
3008         /**
3009          * Flush the protection cache in this object and force reload from the database.
3010          * This is used when updating protection from WikiPage::doUpdateRestrictions().
3011          */
3012         public function flushRestrictions() {
3013                 $this->mRestrictionsLoaded = false;
3014                 $this->mTitleProtection = null;
3015         }
3016
3017         /**
3018          * Purge expired restrictions from the page_restrictions table
3019          */
3020         static function purgeExpiredRestrictions() {
3021                 if ( wfReadOnly() ) {
3022                         return;
3023                 }
3024
3025                 DeferredUpdates::addUpdate( new AtomicSectionUpdate(
3026                         wfGetDB( DB_MASTER ),
3027                         __METHOD__,
3028                         function ( IDatabase $dbw, $fname ) {
3029                                 $dbw->delete(
3030                                         'page_restrictions',
3031                                         [ 'pr_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ],
3032                                         $fname
3033                                 );
3034                                 $dbw->delete(
3035                                         'protected_titles',
3036                                         [ 'pt_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ],
3037                                         $fname
3038                                 );
3039                         }
3040                 ) );
3041         }
3042
3043         /**
3044          * Does this have subpages?  (Warning, usually requires an extra DB query.)
3045          *
3046          * @return bool
3047          */
3048         public function hasSubpages() {
3049                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
3050                         # Duh
3051                         return false;
3052                 }
3053
3054                 # We dynamically add a member variable for the purpose of this method
3055                 # alone to cache the result.  There's no point in having it hanging
3056                 # around uninitialized in every Title object; therefore we only add it
3057                 # if needed and don't declare it statically.
3058                 if ( $this->mHasSubpages === null ) {
3059                         $this->mHasSubpages = false;
3060                         $subpages = $this->getSubpages( 1 );
3061                         if ( $subpages instanceof TitleArray ) {
3062                                 $this->mHasSubpages = (bool)$subpages->count();
3063                         }
3064                 }
3065
3066                 return $this->mHasSubpages;
3067         }
3068
3069         /**
3070          * Get all subpages of this page.
3071          *
3072          * @param int $limit Maximum number of subpages to fetch; -1 for no limit
3073          * @return TitleArray|array TitleArray, or empty array if this page's namespace
3074          *  doesn't allow subpages
3075          */
3076         public function getSubpages( $limit = -1 ) {
3077                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3078                         return [];
3079                 }
3080
3081                 $dbr = wfGetDB( DB_SLAVE );
3082                 $conds['page_namespace'] = $this->getNamespace();
3083                 $conds[] = 'page_title ' . $dbr->buildLike( $this->getDBkey() . '/', $dbr->anyString() );
3084                 $options = [];
3085                 if ( $limit > -1 ) {
3086                         $options['LIMIT'] = $limit;
3087                 }
3088                 $this->mSubpages = TitleArray::newFromResult(
3089                         $dbr->select( 'page',
3090                                 [ 'page_id', 'page_namespace', 'page_title', 'page_is_redirect' ],
3091                                 $conds,
3092                                 __METHOD__,
3093                                 $options
3094                         )
3095                 );
3096                 return $this->mSubpages;
3097         }
3098
3099         /**
3100          * Is there a version of this page in the deletion archive?
3101          *
3102          * @return int The number of archived revisions
3103          */
3104         public function isDeleted() {
3105                 if ( $this->getNamespace() < 0 ) {
3106                         $n = 0;
3107                 } else {
3108                         $dbr = wfGetDB( DB_SLAVE );
3109
3110                         $n = $dbr->selectField( 'archive', 'COUNT(*)',
3111                                 [ 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ],
3112                                 __METHOD__
3113                         );
3114                         if ( $this->getNamespace() == NS_FILE ) {
3115                                 $n += $dbr->selectField( 'filearchive', 'COUNT(*)',
3116                                         [ 'fa_name' => $this->getDBkey() ],
3117                                         __METHOD__
3118                                 );
3119                         }
3120                 }
3121                 return (int)$n;
3122         }
3123
3124         /**
3125          * Is there a version of this page in the deletion archive?
3126          *
3127          * @return bool
3128          */
3129         public function isDeletedQuick() {
3130                 if ( $this->getNamespace() < 0 ) {
3131                         return false;
3132                 }
3133                 $dbr = wfGetDB( DB_SLAVE );
3134                 $deleted = (bool)$dbr->selectField( 'archive', '1',
3135                         [ 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ],
3136                         __METHOD__
3137                 );
3138                 if ( !$deleted && $this->getNamespace() == NS_FILE ) {
3139                         $deleted = (bool)$dbr->selectField( 'filearchive', '1',
3140                                 [ 'fa_name' => $this->getDBkey() ],
3141                                 __METHOD__
3142                         );
3143                 }
3144                 return $deleted;
3145         }
3146
3147         /**
3148          * Get the article ID for this Title from the link cache,
3149          * adding it if necessary
3150          *
3151          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select
3152          *  for update
3153          * @return int The ID
3154          */
3155         public function getArticleID( $flags = 0 ) {
3156                 if ( $this->getNamespace() < 0 ) {
3157                         $this->mArticleID = 0;
3158                         return $this->mArticleID;
3159                 }
3160                 $linkCache = LinkCache::singleton();
3161                 if ( $flags & self::GAID_FOR_UPDATE ) {
3162                         $oldUpdate = $linkCache->forUpdate( true );
3163                         $linkCache->clearLink( $this );
3164                         $this->mArticleID = $linkCache->addLinkObj( $this );
3165                         $linkCache->forUpdate( $oldUpdate );
3166                 } else {
3167                         if ( -1 == $this->mArticleID ) {
3168                                 $this->mArticleID = $linkCache->addLinkObj( $this );
3169                         }
3170                 }
3171                 return $this->mArticleID;
3172         }
3173
3174         /**
3175          * Is this an article that is a redirect page?
3176          * Uses link cache, adding it if necessary
3177          *
3178          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3179          * @return bool
3180          */
3181         public function isRedirect( $flags = 0 ) {
3182                 if ( !is_null( $this->mRedirect ) ) {
3183                         return $this->mRedirect;
3184                 }
3185                 if ( !$this->getArticleID( $flags ) ) {
3186                         $this->mRedirect = false;
3187                         return $this->mRedirect;
3188                 }
3189
3190                 $linkCache = LinkCache::singleton();
3191                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3192                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'redirect' );
3193                 if ( $cached === null ) {
3194                         # Trust LinkCache's state over our own
3195                         # LinkCache is telling us that the page doesn't exist, despite there being cached
3196                         # data relating to an existing page in $this->mArticleID. Updaters should clear
3197                         # LinkCache as appropriate, or use $flags = Title::GAID_FOR_UPDATE. If that flag is
3198                         # set, then LinkCache will definitely be up to date here, since getArticleID() forces
3199                         # LinkCache to refresh its data from the master.
3200                         $this->mRedirect = false;
3201                         return $this->mRedirect;
3202                 }
3203
3204                 $this->mRedirect = (bool)$cached;
3205
3206                 return $this->mRedirect;
3207         }
3208
3209         /**
3210          * What is the length of this page?
3211          * Uses link cache, adding it if necessary
3212          *
3213          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3214          * @return int
3215          */
3216         public function getLength( $flags = 0 ) {
3217                 if ( $this->mLength != -1 ) {
3218                         return $this->mLength;
3219                 }
3220                 if ( !$this->getArticleID( $flags ) ) {
3221                         $this->mLength = 0;
3222                         return $this->mLength;
3223                 }
3224                 $linkCache = LinkCache::singleton();
3225                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3226                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'length' );
3227                 if ( $cached === null ) {
3228                         # Trust LinkCache's state over our own, as for isRedirect()
3229                         $this->mLength = 0;
3230                         return $this->mLength;
3231                 }
3232
3233                 $this->mLength = intval( $cached );
3234
3235                 return $this->mLength;
3236         }
3237
3238         /**
3239          * What is the page_latest field for this page?
3240          *
3241          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3242          * @return int Int or 0 if the page doesn't exist
3243          */
3244         public function getLatestRevID( $flags = 0 ) {
3245                 if ( !( $flags & Title::GAID_FOR_UPDATE ) && $this->mLatestID !== false ) {
3246                         return intval( $this->mLatestID );
3247                 }
3248                 if ( !$this->getArticleID( $flags ) ) {
3249                         $this->mLatestID = 0;
3250                         return $this->mLatestID;
3251                 }
3252                 $linkCache = LinkCache::singleton();
3253                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3254                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'revision' );
3255                 if ( $cached === null ) {
3256                         # Trust LinkCache's state over our own, as for isRedirect()
3257                         $this->mLatestID = 0;
3258                         return $this->mLatestID;
3259                 }
3260
3261                 $this->mLatestID = intval( $cached );
3262
3263                 return $this->mLatestID;
3264         }
3265
3266         /**
3267          * This clears some fields in this object, and clears any associated
3268          * keys in the "bad links" section of the link cache.
3269          *
3270          * - This is called from WikiPage::doEdit() and WikiPage::insertOn() to allow
3271          * loading of the new page_id. It's also called from
3272          * WikiPage::doDeleteArticleReal()
3273          *
3274          * @param int $newid The new Article ID
3275          */
3276         public function resetArticleID( $newid ) {
3277                 $linkCache = LinkCache::singleton();
3278                 $linkCache->clearLink( $this );
3279
3280                 if ( $newid === false ) {
3281                         $this->mArticleID = -1;
3282                 } else {
3283                         $this->mArticleID = intval( $newid );
3284                 }
3285                 $this->mRestrictionsLoaded = false;
3286                 $this->mRestrictions = [];
3287                 $this->mOldRestrictions = false;
3288                 $this->mRedirect = null;
3289                 $this->mLength = -1;
3290                 $this->mLatestID = false;
3291                 $this->mContentModel = false;
3292                 $this->mEstimateRevisions = null;
3293                 $this->mPageLanguage = false;
3294                 $this->mDbPageLanguage = false;
3295                 $this->mIsBigDeletion = null;
3296         }
3297
3298         public static function clearCaches() {
3299                 $linkCache = LinkCache::singleton();
3300                 $linkCache->clear();
3301
3302                 $titleCache = self::getTitleCache();
3303                 $titleCache->clear();
3304         }
3305
3306         /**
3307          * Capitalize a text string for a title if it belongs to a namespace that capitalizes
3308          *
3309          * @param string $text Containing title to capitalize
3310          * @param int $ns Namespace index, defaults to NS_MAIN
3311          * @return string Containing capitalized title
3312          */
3313         public static function capitalize( $text, $ns = NS_MAIN ) {
3314                 global $wgContLang;
3315
3316                 if ( MWNamespace::isCapitalized( $ns ) ) {
3317                         return $wgContLang->ucfirst( $text );
3318                 } else {
3319                         return $text;
3320                 }
3321         }
3322
3323         /**
3324          * Secure and split - main initialisation function for this object
3325          *
3326          * Assumes that mDbkeyform has been set, and is urldecoded
3327          * and uses underscores, but not otherwise munged.  This function
3328          * removes illegal characters, splits off the interwiki and
3329          * namespace prefixes, sets the other forms, and canonicalizes
3330          * everything.
3331          *
3332          * @throws MalformedTitleException On invalid titles
3333          * @return bool True on success
3334          */
3335         private function secureAndSplit() {
3336                 # Initialisation
3337                 $this->mInterwiki = '';
3338                 $this->mFragment = '';
3339                 $this->mNamespace = $this->mDefaultNamespace; # Usually NS_MAIN
3340
3341                 $dbkey = $this->mDbkeyform;
3342
3343                 // @note: splitTitleString() is a temporary hack to allow MediaWikiTitleCodec to share
3344                 //        the parsing code with Title, while avoiding massive refactoring.
3345                 // @todo: get rid of secureAndSplit, refactor parsing code.
3346                 $titleParser = self::getMediaWikiTitleCodec();
3347                 // MalformedTitleException can be thrown here
3348                 $parts = $titleParser->splitTitleString( $dbkey, $this->getDefaultNamespace() );
3349
3350                 # Fill fields
3351                 $this->setFragment( '#' . $parts['fragment'] );
3352                 $this->mInterwiki = $parts['interwiki'];
3353                 $this->mLocalInterwiki = $parts['local_interwiki'];
3354                 $this->mNamespace = $parts['namespace'];
3355                 $this->mUserCaseDBKey = $parts['user_case_dbkey'];
3356
3357                 $this->mDbkeyform = $parts['dbkey'];
3358                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
3359                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
3360
3361                 # We already know that some pages won't be in the database!
3362                 if ( $this->isExternal() || $this->mNamespace == NS_SPECIAL ) {
3363                         $this->mArticleID = 0;
3364                 }
3365
3366                 return true;
3367         }
3368
3369         /**
3370          * Get an array of Title objects linking to this Title
3371          * Also stores the IDs in the link cache.
3372          *
3373          * WARNING: do not use this function on arbitrary user-supplied titles!
3374          * On heavily-used templates it will max out the memory.
3375          *
3376          * @param array $options May be FOR UPDATE
3377          * @param string $table Table name
3378          * @param string $prefix Fields prefix
3379          * @return Title[] Array of Title objects linking here
3380          */
3381         public function getLinksTo( $options = [], $table = 'pagelinks', $prefix = 'pl' ) {
3382                 if ( count( $options ) > 0 ) {
3383                         $db = wfGetDB( DB_MASTER );
3384                 } else {
3385                         $db = wfGetDB( DB_SLAVE );
3386                 }
3387
3388                 $res = $db->select(
3389                         [ 'page', $table ],
3390                         self::getSelectFields(),
3391                         [
3392                                 "{$prefix}_from=page_id",
3393                                 "{$prefix}_namespace" => $this->getNamespace(),
3394                                 "{$prefix}_title" => $this->getDBkey() ],
3395                         __METHOD__,
3396                         $options
3397                 );
3398
3399                 $retVal = [];
3400                 if ( $res->numRows() ) {
3401                         $linkCache = LinkCache::singleton();
3402                         foreach ( $res as $row ) {
3403                                 $titleObj = Title::makeTitle( $row->page_namespace, $row->page_title );
3404                                 if ( $titleObj ) {
3405                                         $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3406                                         $retVal[] = $titleObj;
3407                                 }
3408                         }
3409                 }
3410                 return $retVal;
3411         }
3412
3413         /**
3414          * Get an array of Title objects using this Title as a template
3415          * Also stores the IDs in the link cache.
3416          *
3417          * WARNING: do not use this function on arbitrary user-supplied titles!
3418          * On heavily-used templates it will max out the memory.
3419          *
3420          * @param array $options Query option to Database::select()
3421          * @return Title[] Array of Title the Title objects linking here
3422          */
3423         public function getTemplateLinksTo( $options = [] ) {
3424                 return $this->getLinksTo( $options, 'templatelinks', 'tl' );
3425         }
3426
3427         /**
3428          * Get an array of Title objects linked from this Title
3429          * Also stores the IDs in the link cache.
3430          *
3431          * WARNING: do not use this function on arbitrary user-supplied titles!
3432          * On heavily-used templates it will max out the memory.
3433          *
3434          * @param array $options Query option to Database::select()
3435          * @param string $table Table name
3436          * @param string $prefix Fields prefix
3437          * @return array Array of Title objects linking here
3438          */
3439         public function getLinksFrom( $options = [], $table = 'pagelinks', $prefix = 'pl' ) {
3440                 $id = $this->getArticleID();
3441
3442                 # If the page doesn't exist; there can't be any link from this page
3443                 if ( !$id ) {
3444                         return [];
3445                 }
3446
3447                 $db = wfGetDB( DB_SLAVE );
3448
3449                 $blNamespace = "{$prefix}_namespace";
3450                 $blTitle = "{$prefix}_title";
3451
3452                 $res = $db->select(
3453                         [ $table, 'page' ],
3454                         array_merge(
3455                                 [ $blNamespace, $blTitle ],
3456                                 WikiPage::selectFields()
3457                         ),
3458                         [ "{$prefix}_from" => $id ],
3459                         __METHOD__,
3460                         $options,
3461                         [ 'page' => [
3462                                 'LEFT JOIN',
3463                                 [ "page_namespace=$blNamespace", "page_title=$blTitle" ]
3464                         ] ]
3465                 );
3466
3467                 $retVal = [];
3468                 $linkCache = LinkCache::singleton();
3469                 foreach ( $res as $row ) {
3470                         if ( $row->page_id ) {
3471                                 $titleObj = Title::newFromRow( $row );
3472                         } else {
3473                                 $titleObj = Title::makeTitle( $row->$blNamespace, $row->$blTitle );
3474                                 $linkCache->addBadLinkObj( $titleObj );
3475                         }
3476                         $retVal[] = $titleObj;
3477                 }
3478
3479                 return $retVal;
3480         }
3481
3482         /**
3483          * Get an array of Title objects used on this Title as a template
3484          * Also stores the IDs in the link cache.
3485          *
3486          * WARNING: do not use this function on arbitrary user-supplied titles!
3487          * On heavily-used templates it will max out the memory.
3488          *
3489          * @param array $options May be FOR UPDATE
3490          * @return Title[] Array of Title the Title objects used here
3491          */
3492         public function getTemplateLinksFrom( $options = [] ) {
3493                 return $this->getLinksFrom( $options, 'templatelinks', 'tl' );
3494         }
3495
3496         /**
3497          * Get an array of Title objects referring to non-existent articles linked
3498          * from this page.
3499          *
3500          * @todo check if needed (used only in SpecialBrokenRedirects.php, and
3501          *   should use redirect table in this case).
3502          * @return Title[] Array of Title the Title objects
3503          */
3504         public function getBrokenLinksFrom() {
3505                 if ( $this->getArticleID() == 0 ) {
3506                         # All links from article ID 0 are false positives
3507                         return [];
3508                 }
3509
3510                 $dbr = wfGetDB( DB_SLAVE );
3511                 $res = $dbr->select(
3512                         [ 'page', 'pagelinks' ],
3513                         [ 'pl_namespace', 'pl_title' ],
3514                         [
3515                                 'pl_from' => $this->getArticleID(),
3516                                 'page_namespace IS NULL'
3517                         ],
3518                         __METHOD__, [],
3519                         [
3520                                 'page' => [
3521                                         'LEFT JOIN',
3522                                         [ 'pl_namespace=page_namespace', 'pl_title=page_title' ]
3523                                 ]
3524                         ]
3525                 );
3526
3527                 $retVal = [];
3528                 foreach ( $res as $row ) {
3529                         $retVal[] = Title::makeTitle( $row->pl_namespace, $row->pl_title );
3530                 }
3531                 return $retVal;
3532         }
3533
3534         /**
3535          * Get a list of URLs to purge from the CDN cache when this
3536          * page changes
3537          *
3538          * @return string[] Array of String the URLs
3539          */
3540         public function getCdnUrls() {
3541                 $urls = [
3542                         $this->getInternalURL(),
3543                         $this->getInternalURL( 'action=history' )
3544                 ];
3545
3546                 $pageLang = $this->getPageLanguage();
3547                 if ( $pageLang->hasVariants() ) {
3548                         $variants = $pageLang->getVariants();
3549                         foreach ( $variants as $vCode ) {
3550                                 $urls[] = $this->getInternalURL( $vCode );
3551                         }
3552                 }
3553
3554                 // If we are looking at a css/js user subpage, purge the action=raw.
3555                 if ( $this->isJsSubpage() ) {
3556                         $urls[] = $this->getInternalURL( 'action=raw&ctype=text/javascript' );
3557                 } elseif ( $this->isCssSubpage() ) {
3558                         $urls[] = $this->getInternalURL( 'action=raw&ctype=text/css' );
3559                 }
3560
3561                 Hooks::run( 'TitleSquidURLs', [ $this, &$urls ] );
3562                 return $urls;
3563         }
3564
3565         /**
3566          * @deprecated since 1.27 use getCdnUrls()
3567          */
3568         public function getSquidURLs() {
3569                 return $this->getCdnUrls();
3570         }
3571
3572         /**
3573          * Purge all applicable CDN URLs
3574          */
3575         public function purgeSquid() {
3576                 DeferredUpdates::addUpdate(
3577                         new CdnCacheUpdate( $this->getCdnUrls() ),
3578                         DeferredUpdates::PRESEND
3579                 );
3580         }
3581
3582         /**
3583          * Move this page without authentication
3584          *
3585          * @deprecated since 1.25 use MovePage class instead
3586          * @param Title $nt The new page Title
3587          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3588          */
3589         public function moveNoAuth( &$nt ) {
3590                 wfDeprecated( __METHOD__, '1.25' );
3591                 return $this->moveTo( $nt, false );
3592         }
3593
3594         /**
3595          * Check whether a given move operation would be valid.
3596          * Returns true if ok, or a getUserPermissionsErrors()-like array otherwise
3597          *
3598          * @deprecated since 1.25, use MovePage's methods instead
3599          * @param Title $nt The new title
3600          * @param bool $auth Whether to check user permissions (uses $wgUser)
3601          * @param string $reason Is the log summary of the move, used for spam checking
3602          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3603          */
3604         public function isValidMoveOperation( &$nt, $auth = true, $reason = '' ) {
3605                 global $wgUser;
3606
3607                 if ( !( $nt instanceof Title ) ) {
3608                         // Normally we'd add this to $errors, but we'll get
3609                         // lots of syntax errors if $nt is not an object
3610                         return [ [ 'badtitletext' ] ];
3611                 }
3612
3613                 $mp = new MovePage( $this, $nt );
3614                 $errors = $mp->isValidMove()->getErrorsArray();
3615                 if ( $auth ) {
3616                         $errors = wfMergeErrorArrays(
3617                                 $errors,
3618                                 $mp->checkPermissions( $wgUser, $reason )->getErrorsArray()
3619                         );
3620                 }
3621
3622                 return $errors ?: true;
3623         }
3624
3625         /**
3626          * Check if the requested move target is a valid file move target
3627          * @todo move this to MovePage
3628          * @param Title $nt Target title
3629          * @return array List of errors
3630          */
3631         protected function validateFileMoveOperation( $nt ) {
3632                 global $wgUser;
3633
3634                 $errors = [];
3635
3636                 $destFile = wfLocalFile( $nt );
3637                 $destFile->load( File::READ_LATEST );
3638                 if ( !$wgUser->isAllowed( 'reupload-shared' )
3639                         && !$destFile->exists() && wfFindFile( $nt )
3640                 ) {
3641                         $errors[] = [ 'file-exists-sharedrepo' ];
3642                 }
3643
3644                 return $errors;
3645         }
3646
3647         /**
3648          * Move a title to a new location
3649          *
3650          * @deprecated since 1.25, use the MovePage class instead
3651          * @param Title $nt The new title
3652          * @param bool $auth Indicates whether $wgUser's permissions
3653          *  should be checked
3654          * @param string $reason The reason for the move
3655          * @param bool $createRedirect Whether to create a redirect from the old title to the new title.
3656          *  Ignored if the user doesn't have the suppressredirect right.
3657          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3658          */
3659         public function moveTo( &$nt, $auth = true, $reason = '', $createRedirect = true ) {
3660                 global $wgUser;
3661                 $err = $this->isValidMoveOperation( $nt, $auth, $reason );
3662                 if ( is_array( $err ) ) {
3663                         // Auto-block user's IP if the account was "hard" blocked
3664                         $wgUser->spreadAnyEditBlock();
3665                         return $err;
3666                 }
3667                 // Check suppressredirect permission
3668                 if ( $auth && !$wgUser->isAllowed( 'suppressredirect' ) ) {
3669                         $createRedirect = true;
3670                 }
3671
3672                 $mp = new MovePage( $this, $nt );
3673                 $status = $mp->move( $wgUser, $reason, $createRedirect );
3674                 if ( $status->isOK() ) {
3675                         return true;
3676                 } else {
3677                         return $status->getErrorsArray();
3678                 }
3679         }
3680
3681         /**
3682          * Move this page's subpages to be subpages of $nt
3683          *
3684          * @param Title $nt Move target
3685          * @param bool $auth Whether $wgUser's permissions should be checked
3686          * @param string $reason The reason for the move
3687          * @param bool $createRedirect Whether to create redirects from the old subpages to
3688          *     the new ones Ignored if the user doesn't have the 'suppressredirect' right
3689          * @return array Array with old page titles as keys, and strings (new page titles) or
3690          *     arrays (errors) as values, or an error array with numeric indices if no pages
3691          *     were moved
3692          */
3693         public function moveSubpages( $nt, $auth = true, $reason = '', $createRedirect = true ) {
3694                 global $wgMaximumMovedPages;
3695                 // Check permissions
3696                 if ( !$this->userCan( 'move-subpages' ) ) {
3697                         return [ 'cant-move-subpages' ];
3698                 }
3699                 // Do the source and target namespaces support subpages?
3700                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3701                         return [ 'namespace-nosubpages',
3702                                 MWNamespace::getCanonicalName( $this->getNamespace() ) ];
3703                 }
3704                 if ( !MWNamespace::hasSubpages( $nt->getNamespace() ) ) {
3705                         return [ 'namespace-nosubpages',
3706                                 MWNamespace::getCanonicalName( $nt->getNamespace() ) ];
3707                 }
3708
3709                 $subpages = $this->getSubpages( $wgMaximumMovedPages + 1 );
3710                 $retval = [];
3711                 $count = 0;
3712                 foreach ( $subpages as $oldSubpage ) {
3713                         $count++;
3714                         if ( $count > $wgMaximumMovedPages ) {
3715                                 $retval[$oldSubpage->getPrefixedText()] =
3716                                                 [ 'movepage-max-pages',
3717                                                         $wgMaximumMovedPages ];
3718                                 break;
3719                         }
3720
3721                         // We don't know whether this function was called before
3722                         // or after moving the root page, so check both
3723                         // $this and $nt
3724                         if ( $oldSubpage->getArticleID() == $this->getArticleID()
3725                                 || $oldSubpage->getArticleID() == $nt->getArticleID()
3726                         ) {
3727                                 // When moving a page to a subpage of itself,
3728                                 // don't move it twice
3729                                 continue;
3730                         }
3731                         $newPageName = preg_replace(
3732                                         '#^' . preg_quote( $this->getDBkey(), '#' ) . '#',
3733                                         StringUtils::escapeRegexReplacement( $nt->getDBkey() ), # bug 21234
3734                                         $oldSubpage->getDBkey() );
3735                         if ( $oldSubpage->isTalkPage() ) {
3736                                 $newNs = $nt->getTalkPage()->getNamespace();
3737                         } else {
3738                                 $newNs = $nt->getSubjectPage()->getNamespace();
3739                         }
3740                         # Bug 14385: we need makeTitleSafe because the new page names may
3741                         # be longer than 255 characters.
3742                         $newSubpage = Title::makeTitleSafe( $newNs, $newPageName );
3743
3744                         $success = $oldSubpage->moveTo( $newSubpage, $auth, $reason, $createRedirect );
3745                         if ( $success === true ) {
3746                                 $retval[$oldSubpage->getPrefixedText()] = $newSubpage->getPrefixedText();
3747                         } else {
3748                                 $retval[$oldSubpage->getPrefixedText()] = $success;
3749                         }
3750                 }
3751                 return $retval;
3752         }
3753
3754         /**
3755          * Checks if this page is just a one-rev redirect.
3756          * Adds lock, so don't use just for light purposes.
3757          *
3758          * @return bool
3759          */
3760         public function isSingleRevRedirect() {
3761                 global $wgContentHandlerUseDB;
3762
3763                 $dbw = wfGetDB( DB_MASTER );
3764
3765                 # Is it a redirect?
3766                 $fields = [ 'page_is_redirect', 'page_latest', 'page_id' ];
3767                 if ( $wgContentHandlerUseDB ) {
3768                         $fields[] = 'page_content_model';
3769                 }
3770
3771                 $row = $dbw->selectRow( 'page',
3772                         $fields,
3773                         $this->pageCond(),
3774                         __METHOD__,
3775                         [ 'FOR UPDATE' ]
3776                 );
3777                 # Cache some fields we may want
3778                 $this->mArticleID = $row ? intval( $row->page_id ) : 0;
3779                 $this->mRedirect = $row ? (bool)$row->page_is_redirect : false;
3780                 $this->mLatestID = $row ? intval( $row->page_latest ) : false;
3781                 $this->mContentModel = $row && isset( $row->page_content_model )
3782                         ? strval( $row->page_content_model )
3783                         : false;
3784
3785                 if ( !$this->mRedirect ) {
3786                         return false;
3787                 }
3788                 # Does the article have a history?
3789                 $row = $dbw->selectField( [ 'page', 'revision' ],
3790                         'rev_id',
3791                         [ 'page_namespace' => $this->getNamespace(),
3792                                 'page_title' => $this->getDBkey(),
3793                                 'page_id=rev_page',
3794                                 'page_latest != rev_id'
3795                         ],
3796                         __METHOD__,
3797                         [ 'FOR UPDATE' ]
3798                 );
3799                 # Return true if there was no history
3800                 return ( $row === false );
3801         }
3802
3803         /**
3804          * Checks if $this can be moved to a given Title
3805          * - Selects for update, so don't call it unless you mean business
3806          *
3807          * @deprecated since 1.25, use MovePage's methods instead
3808          * @param Title $nt The new title to check
3809          * @return bool
3810          */
3811         public function isValidMoveTarget( $nt ) {
3812                 # Is it an existing file?
3813                 if ( $nt->getNamespace() == NS_FILE ) {
3814                         $file = wfLocalFile( $nt );
3815                         $file->load( File::READ_LATEST );
3816                         if ( $file->exists() ) {
3817                                 wfDebug( __METHOD__ . ": file exists\n" );
3818                                 return false;
3819                         }
3820                 }
3821                 # Is it a redirect with no history?
3822                 if ( !$nt->isSingleRevRedirect() ) {
3823                         wfDebug( __METHOD__ . ": not a one-rev redirect\n" );
3824                         return false;
3825                 }
3826                 # Get the article text
3827                 $rev = Revision::newFromTitle( $nt, false, Revision::READ_LATEST );
3828                 if ( !is_object( $rev ) ) {
3829                         return false;
3830                 }
3831                 $content = $rev->getContent();
3832                 # Does the redirect point to the source?
3833                 # Or is it a broken self-redirect, usually caused by namespace collisions?
3834                 $redirTitle = $content ? $content->getRedirectTarget() : null;
3835
3836                 if ( $redirTitle ) {
3837                         if ( $redirTitle->getPrefixedDBkey() != $this->getPrefixedDBkey() &&
3838                                 $redirTitle->getPrefixedDBkey() != $nt->getPrefixedDBkey() ) {
3839                                 wfDebug( __METHOD__ . ": redirect points to other page\n" );
3840                                 return false;
3841                         } else {
3842                                 return true;
3843                         }
3844                 } else {
3845                         # Fail safe (not a redirect after all. strange.)
3846                         wfDebug( __METHOD__ . ": failsafe: database sais " . $nt->getPrefixedDBkey() .
3847                                                 " is a redirect, but it doesn't contain a valid redirect.\n" );
3848                         return false;
3849                 }
3850         }
3851
3852         /**
3853          * Get categories to which this Title belongs and return an array of
3854          * categories' names.
3855          *
3856          * @return array Array of parents in the form:
3857          *        $parent => $currentarticle
3858          */
3859         public function getParentCategories() {
3860                 global $wgContLang;
3861
3862                 $data = [];
3863
3864                 $titleKey = $this->getArticleID();
3865
3866                 if ( $titleKey === 0 ) {
3867                         return $data;
3868                 }
3869
3870                 $dbr = wfGetDB( DB_SLAVE );
3871
3872                 $res = $dbr->select(
3873                         'categorylinks',
3874                         'cl_to',
3875                         [ 'cl_from' => $titleKey ],
3876                         __METHOD__
3877                 );
3878
3879                 if ( $res->numRows() > 0 ) {
3880                         foreach ( $res as $row ) {
3881                                 // $data[] = Title::newFromText($wgContLang->getNsText ( NS_CATEGORY ).':'.$row->cl_to);
3882                                 $data[$wgContLang->getNsText( NS_CATEGORY ) . ':' . $row->cl_to] = $this->getFullText();
3883                         }
3884                 }
3885                 return $data;
3886         }
3887
3888         /**
3889          * Get a tree of parent categories
3890          *
3891          * @param array $children Array with the children in the keys, to check for circular refs
3892          * @return array Tree of parent categories
3893          */
3894         public function getParentCategoryTree( $children = [] ) {
3895                 $stack = [];
3896                 $parents = $this->getParentCategories();
3897
3898                 if ( $parents ) {
3899                         foreach ( $parents as $parent => $current ) {
3900                                 if ( array_key_exists( $parent, $children ) ) {
3901                                         # Circular reference
3902                                         $stack[$parent] = [];
3903                                 } else {
3904                                         $nt = Title::newFromText( $parent );
3905                                         if ( $nt ) {
3906                                                 $stack[$parent] = $nt->getParentCategoryTree( $children + [ $parent => 1 ] );
3907                                         }
3908                                 }
3909                         }
3910                 }
3911
3912                 return $stack;
3913         }
3914
3915         /**
3916          * Get an associative array for selecting this title from
3917          * the "page" table
3918          *
3919          * @return array Array suitable for the $where parameter of DB::select()
3920          */
3921         public function pageCond() {
3922                 if ( $this->mArticleID > 0 ) {
3923                         // PK avoids secondary lookups in InnoDB, shouldn't hurt other DBs
3924                         return [ 'page_id' => $this->mArticleID ];
3925                 } else {
3926                         return [ 'page_namespace' => $this->mNamespace, 'page_title' => $this->mDbkeyform ];
3927                 }
3928         }
3929
3930         /**
3931          * Get the revision ID of the previous revision
3932          *
3933          * @param int $revId Revision ID. Get the revision that was before this one.
3934          * @param int $flags Title::GAID_FOR_UPDATE
3935          * @return int|bool Old revision ID, or false if none exists
3936          */
3937         public function getPreviousRevisionID( $revId, $flags = 0 ) {
3938                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
3939                 $revId = $db->selectField( 'revision', 'rev_id',
3940                         [
3941                                 'rev_page' => $this->getArticleID( $flags ),
3942                                 'rev_id < ' . intval( $revId )
3943                         ],
3944                         __METHOD__,
3945                         [ 'ORDER BY' => 'rev_id DESC' ]
3946                 );
3947
3948                 if ( $revId === false ) {
3949                         return false;
3950                 } else {
3951                         return intval( $revId );
3952                 }
3953         }
3954
3955         /**
3956          * Get the revision ID of the next revision
3957          *
3958          * @param int $revId Revision ID. Get the revision that was after this one.
3959          * @param int $flags Title::GAID_FOR_UPDATE
3960          * @return int|bool Next revision ID, or false if none exists
3961          */
3962         public function getNextRevisionID( $revId, $flags = 0 ) {
3963                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
3964                 $revId = $db->selectField( 'revision', 'rev_id',
3965                         [
3966                                 'rev_page' => $this->getArticleID( $flags ),
3967                                 'rev_id > ' . intval( $revId )
3968                         ],
3969                         __METHOD__,
3970                         [ 'ORDER BY' => 'rev_id' ]
3971                 );
3972
3973                 if ( $revId === false ) {
3974                         return false;
3975                 } else {
3976                         return intval( $revId );
3977                 }
3978         }
3979
3980         /**
3981          * Get the first revision of the page
3982          *
3983          * @param int $flags Title::GAID_FOR_UPDATE
3984          * @return Revision|null If page doesn't exist
3985          */
3986         public function getFirstRevision( $flags = 0 ) {
3987                 $pageId = $this->getArticleID( $flags );
3988                 if ( $pageId ) {
3989                         $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
3990                         $row = $db->selectRow( 'revision', Revision::selectFields(),
3991                                 [ 'rev_page' => $pageId ],
3992                                 __METHOD__,
3993                                 [ 'ORDER BY' => 'rev_timestamp ASC', 'LIMIT' => 1 ]
3994                         );
3995                         if ( $row ) {
3996                                 return new Revision( $row );
3997                         }
3998                 }
3999                 return null;
4000         }
4001
4002         /**
4003          * Get the oldest revision timestamp of this page
4004          *
4005          * @param int $flags Title::GAID_FOR_UPDATE
4006          * @return string MW timestamp
4007          */
4008         public function getEarliestRevTime( $flags = 0 ) {
4009                 $rev = $this->getFirstRevision( $flags );
4010                 return $rev ? $rev->getTimestamp() : null;
4011         }
4012
4013         /**
4014          * Check if this is a new page
4015          *
4016          * @return bool
4017          */
4018         public function isNewPage() {
4019                 $dbr = wfGetDB( DB_SLAVE );
4020                 return (bool)$dbr->selectField( 'page', 'page_is_new', $this->pageCond(), __METHOD__ );
4021         }
4022
4023         /**
4024          * Check whether the number of revisions of this page surpasses $wgDeleteRevisionsLimit
4025          *
4026          * @return bool
4027          */
4028         public function isBigDeletion() {
4029                 global $wgDeleteRevisionsLimit;
4030
4031                 if ( !$wgDeleteRevisionsLimit ) {
4032                         return false;
4033                 }
4034
4035                 if ( $this->mIsBigDeletion === null ) {
4036                         $dbr = wfGetDB( DB_SLAVE );
4037
4038                         $revCount = $dbr->selectRowCount(
4039                                 'revision',
4040                                 '1',
4041                                 [ 'rev_page' => $this->getArticleID() ],
4042                                 __METHOD__,
4043                                 [ 'LIMIT' => $wgDeleteRevisionsLimit + 1 ]
4044                         );
4045
4046                         $this->mIsBigDeletion = $revCount > $wgDeleteRevisionsLimit;
4047                 }
4048
4049                 return $this->mIsBigDeletion;
4050         }
4051
4052         /**
4053          * Get the approximate revision count of this page.
4054          *
4055          * @return int
4056          */
4057         public function estimateRevisionCount() {
4058                 if ( !$this->exists() ) {
4059                         return 0;
4060                 }
4061
4062                 if ( $this->mEstimateRevisions === null ) {
4063                         $dbr = wfGetDB( DB_SLAVE );
4064                         $this->mEstimateRevisions = $dbr->estimateRowCount( 'revision', '*',
4065                                 [ 'rev_page' => $this->getArticleID() ], __METHOD__ );
4066                 }
4067
4068                 return $this->mEstimateRevisions;
4069         }
4070
4071         /**
4072          * Get the number of revisions between the given revision.
4073          * Used for diffs and other things that really need it.
4074          *
4075          * @param int|Revision $old Old revision or rev ID (first before range)
4076          * @param int|Revision $new New revision or rev ID (first after range)
4077          * @param int|null $max Limit of Revisions to count, will be incremented to detect truncations
4078          * @return int Number of revisions between these revisions.
4079          */
4080         public function countRevisionsBetween( $old, $new, $max = null ) {
4081                 if ( !( $old instanceof Revision ) ) {
4082                         $old = Revision::newFromTitle( $this, (int)$old );
4083                 }
4084                 if ( !( $new instanceof Revision ) ) {
4085                         $new = Revision::newFromTitle( $this, (int)$new );
4086                 }
4087                 if ( !$old || !$new ) {
4088                         return 0; // nothing to compare
4089                 }
4090                 $dbr = wfGetDB( DB_SLAVE );
4091                 $conds = [
4092                         'rev_page' => $this->getArticleID(),
4093                         'rev_timestamp > ' . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4094                         'rev_timestamp < ' . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4095                 ];
4096                 if ( $max !== null ) {
4097                         return $dbr->selectRowCount( 'revision', '1',
4098                                 $conds,
4099                                 __METHOD__,
4100                                 [ 'LIMIT' => $max + 1 ] // extra to detect truncation
4101                         );
4102                 } else {
4103                         return (int)$dbr->selectField( 'revision', 'count(*)', $conds, __METHOD__ );
4104                 }
4105         }
4106
4107         /**
4108          * Get the authors between the given revisions or revision IDs.
4109          * Used for diffs and other things that really need it.
4110          *
4111          * @since 1.23
4112          *
4113          * @param int|Revision $old Old revision or rev ID (first before range by default)
4114          * @param int|Revision $new New revision or rev ID (first after range by default)
4115          * @param int $limit Maximum number of authors
4116          * @param string|array $options (Optional): Single option, or an array of options:
4117          *     'include_old' Include $old in the range; $new is excluded.
4118          *     'include_new' Include $new in the range; $old is excluded.
4119          *     'include_both' Include both $old and $new in the range.
4120          *     Unknown option values are ignored.
4121          * @return array|null Names of revision authors in the range; null if not both revisions exist
4122          */
4123         public function getAuthorsBetween( $old, $new, $limit, $options = [] ) {
4124                 if ( !( $old instanceof Revision ) ) {
4125                         $old = Revision::newFromTitle( $this, (int)$old );
4126                 }
4127                 if ( !( $new instanceof Revision ) ) {
4128                         $new = Revision::newFromTitle( $this, (int)$new );
4129                 }
4130                 // XXX: what if Revision objects are passed in, but they don't refer to this title?
4131                 // Add $old->getPage() != $new->getPage() || $old->getPage() != $this->getArticleID()
4132                 // in the sanity check below?
4133                 if ( !$old || !$new ) {
4134                         return null; // nothing to compare
4135                 }
4136                 $authors = [];
4137                 $old_cmp = '>';
4138                 $new_cmp = '<';
4139                 $options = (array)$options;
4140                 if ( in_array( 'include_old', $options ) ) {
4141                         $old_cmp = '>=';
4142                 }
4143                 if ( in_array( 'include_new', $options ) ) {
4144                         $new_cmp = '<=';
4145                 }
4146                 if ( in_array( 'include_both', $options ) ) {
4147                         $old_cmp = '>=';
4148                         $new_cmp = '<=';
4149                 }
4150                 // No DB query needed if $old and $new are the same or successive revisions:
4151                 if ( $old->getId() === $new->getId() ) {
4152                         return ( $old_cmp === '>' && $new_cmp === '<' ) ?
4153                                 [] :
4154                                 [ $old->getUserText( Revision::RAW ) ];
4155                 } elseif ( $old->getId() === $new->getParentId() ) {
4156                         if ( $old_cmp === '>=' && $new_cmp === '<=' ) {
4157                                 $authors[] = $old->getUserText( Revision::RAW );
4158                                 if ( $old->getUserText( Revision::RAW ) != $new->getUserText( Revision::RAW ) ) {
4159                                         $authors[] = $new->getUserText( Revision::RAW );
4160                                 }
4161                         } elseif ( $old_cmp === '>=' ) {
4162                                 $authors[] = $old->getUserText( Revision::RAW );
4163                         } elseif ( $new_cmp === '<=' ) {
4164                                 $authors[] = $new->getUserText( Revision::RAW );
4165                         }
4166                         return $authors;
4167                 }
4168                 $dbr = wfGetDB( DB_SLAVE );
4169                 $res = $dbr->select( 'revision', 'DISTINCT rev_user_text',
4170                         [
4171                                 'rev_page' => $this->getArticleID(),
4172                                 "rev_timestamp $old_cmp " . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4173                                 "rev_timestamp $new_cmp " . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4174                         ], __METHOD__,
4175                         [ 'LIMIT' => $limit + 1 ] // add one so caller knows it was truncated
4176                 );
4177                 foreach ( $res as $row ) {
4178                         $authors[] = $row->rev_user_text;
4179                 }
4180                 return $authors;
4181         }
4182
4183         /**
4184          * Get the number of authors between the given revisions or revision IDs.
4185          * Used for diffs and other things that really need it.
4186          *
4187          * @param int|Revision $old Old revision or rev ID (first before range by default)
4188          * @param int|Revision $new New revision or rev ID (first after range by default)
4189          * @param int $limit Maximum number of authors
4190          * @param string|array $options (Optional): Single option, or an array of options:
4191          *     'include_old' Include $old in the range; $new is excluded.
4192          *     'include_new' Include $new in the range; $old is excluded.
4193          *     'include_both' Include both $old and $new in the range.
4194          *     Unknown option values are ignored.
4195          * @return int Number of revision authors in the range; zero if not both revisions exist
4196          */
4197         public function countAuthorsBetween( $old, $new, $limit, $options = [] ) {
4198                 $authors = $this->getAuthorsBetween( $old, $new, $limit, $options );
4199                 return $authors ? count( $authors ) : 0;
4200         }
4201
4202         /**
4203          * Compare with another title.
4204          *
4205          * @param Title $title
4206          * @return bool
4207          */
4208         public function equals( Title $title ) {
4209                 // Note: === is necessary for proper matching of number-like titles.
4210                 return $this->getInterwiki() === $title->getInterwiki()
4211                         && $this->getNamespace() == $title->getNamespace()
4212                         && $this->getDBkey() === $title->getDBkey();
4213         }
4214
4215         /**
4216          * Check if this title is a subpage of another title
4217          *
4218          * @param Title $title
4219          * @return bool
4220          */
4221         public function isSubpageOf( Title $title ) {
4222                 return $this->getInterwiki() === $title->getInterwiki()
4223                         && $this->getNamespace() == $title->getNamespace()
4224                         && strpos( $this->getDBkey(), $title->getDBkey() . '/' ) === 0;
4225         }
4226
4227         /**
4228          * Check if page exists.  For historical reasons, this function simply
4229          * checks for the existence of the title in the page table, and will
4230          * thus return false for interwiki links, special pages and the like.
4231          * If you want to know if a title can be meaningfully viewed, you should
4232          * probably call the isKnown() method instead.
4233          *
4234          * @param int $flags An optional bit field; may be Title::GAID_FOR_UPDATE to check
4235          *   from master/for update
4236          * @return bool
4237          */
4238         public function exists( $flags = 0 ) {
4239                 $exists = $this->getArticleID( $flags ) != 0;
4240                 Hooks::run( 'TitleExists', [ $this, &$exists ] );
4241                 return $exists;
4242         }
4243
4244         /**
4245          * Should links to this title be shown as potentially viewable (i.e. as
4246          * "bluelinks"), even if there's no record by this title in the page
4247          * table?
4248          *
4249          * This function is semi-deprecated for public use, as well as somewhat
4250          * misleadingly named.  You probably just want to call isKnown(), which
4251          * calls this function internally.
4252          *
4253          * (ISSUE: Most of these checks are cheap, but the file existence check
4254          * can potentially be quite expensive.  Including it here fixes a lot of
4255          * existing code, but we might want to add an optional parameter to skip
4256          * it and any other expensive checks.)
4257          *
4258          * @return bool
4259          */
4260         public function isAlwaysKnown() {
4261                 $isKnown = null;
4262
4263                 /**
4264                  * Allows overriding default behavior for determining if a page exists.
4265                  * If $isKnown is kept as null, regular checks happen. If it's
4266                  * a boolean, this value is returned by the isKnown method.
4267                  *
4268                  * @since 1.20
4269                  *
4270                  * @param Title $title
4271                  * @param bool|null $isKnown
4272                  */
4273                 Hooks::run( 'TitleIsAlwaysKnown', [ $this, &$isKnown ] );
4274
4275                 if ( !is_null( $isKnown ) ) {
4276                         return $isKnown;
4277                 }
4278
4279                 if ( $this->isExternal() ) {
4280                         return true;  // any interwiki link might be viewable, for all we know
4281                 }
4282
4283                 switch ( $this->mNamespace ) {
4284                         case NS_MEDIA:
4285                         case NS_FILE:
4286                                 // file exists, possibly in a foreign repo
4287                                 return (bool)wfFindFile( $this );
4288                         case NS_SPECIAL:
4289                                 // valid special page
4290                                 return SpecialPageFactory::exists( $this->getDBkey() );
4291                         case NS_MAIN:
4292                                 // selflink, possibly with fragment
4293                                 return $this->mDbkeyform == '';
4294                         case NS_MEDIAWIKI:
4295                                 // known system message
4296                                 return $this->hasSourceText() !== false;
4297                         default:
4298                                 return false;
4299                 }
4300         }
4301
4302         /**
4303          * Does this title refer to a page that can (or might) be meaningfully
4304          * viewed?  In particular, this function may be used to determine if
4305          * links to the title should be rendered as "bluelinks" (as opposed to
4306          * "redlinks" to non-existent pages).
4307          * Adding something else to this function will cause inconsistency
4308          * since LinkHolderArray calls isAlwaysKnown() and does its own
4309          * page existence check.
4310          *
4311          * @return bool
4312          */
4313         public function isKnown() {
4314                 return $this->isAlwaysKnown() || $this->exists();
4315         }
4316
4317         /**
4318          * Does this page have source text?
4319          *
4320          * @return bool
4321          */
4322         public function hasSourceText() {
4323                 if ( $this->exists() ) {
4324                         return true;
4325                 }
4326
4327                 if ( $this->mNamespace == NS_MEDIAWIKI ) {
4328                         // If the page doesn't exist but is a known system message, default
4329                         // message content will be displayed, same for language subpages-
4330                         // Use always content language to avoid loading hundreds of languages
4331                         // to get the link color.
4332                         global $wgContLang;
4333                         list( $name, ) = MessageCache::singleton()->figureMessage(
4334                                 $wgContLang->lcfirst( $this->getText() )
4335                         );
4336                         $message = wfMessage( $name )->inLanguage( $wgContLang )->useDatabase( false );
4337                         return $message->exists();
4338                 }
4339
4340                 return false;
4341         }
4342
4343         /**
4344          * Get the default message text or false if the message doesn't exist
4345          *
4346          * @return string|bool
4347          */
4348         public function getDefaultMessageText() {
4349                 global $wgContLang;
4350
4351                 if ( $this->getNamespace() != NS_MEDIAWIKI ) { // Just in case
4352                         return false;
4353                 }
4354
4355                 list( $name, $lang ) = MessageCache::singleton()->figureMessage(
4356                         $wgContLang->lcfirst( $this->getText() )
4357                 );
4358                 $message = wfMessage( $name )->inLanguage( $lang )->useDatabase( false );
4359
4360                 if ( $message->exists() ) {
4361                         return $message->plain();
4362                 } else {
4363                         return false;
4364                 }
4365         }
4366
4367         /**
4368          * Updates page_touched for this page; called from LinksUpdate.php
4369          *
4370          * @param string $purgeTime [optional] TS_MW timestamp
4371          * @return bool True if the update succeeded
4372          */
4373         public function invalidateCache( $purgeTime = null ) {
4374                 if ( wfReadOnly() ) {
4375                         return false;
4376                 }
4377
4378                 if ( $this->mArticleID === 0 ) {
4379                         return true; // avoid gap locking if we know it's not there
4380                 }
4381
4382                 $method = __METHOD__;
4383                 $dbw = wfGetDB( DB_MASTER );
4384                 $conds = $this->pageCond();
4385                 $dbw->onTransactionIdle( function () use ( $dbw, $conds, $method, $purgeTime ) {
4386                         $dbTimestamp = $dbw->timestamp( $purgeTime ?: time() );
4387
4388                         $dbw->update(
4389                                 'page',
4390                                 [ 'page_touched' => $dbTimestamp ],
4391                                 $conds + [ 'page_touched < ' . $dbw->addQuotes( $dbTimestamp ) ],
4392                                 $method
4393                         );
4394                 } );
4395
4396                 return true;
4397         }
4398
4399         /**
4400          * Update page_touched timestamps and send CDN purge messages for
4401          * pages linking to this title. May be sent to the job queue depending
4402          * on the number of links. Typically called on create and delete.
4403          */
4404         public function touchLinks() {
4405                 DeferredUpdates::addUpdate( new HTMLCacheUpdate( $this, 'pagelinks' ) );
4406                 if ( $this->getNamespace() == NS_CATEGORY ) {
4407                         DeferredUpdates::addUpdate( new HTMLCacheUpdate( $this, 'categorylinks' ) );
4408                 }
4409         }
4410
4411         /**
4412          * Get the last touched timestamp
4413          *
4414          * @param IDatabase $db Optional db
4415          * @return string Last-touched timestamp
4416          */
4417         public function getTouched( $db = null ) {
4418                 if ( $db === null ) {
4419                         $db = wfGetDB( DB_SLAVE );
4420                 }
4421                 $touched = $db->selectField( 'page', 'page_touched', $this->pageCond(), __METHOD__ );
4422                 return $touched;
4423         }
4424
4425         /**
4426          * Get the timestamp when this page was updated since the user last saw it.
4427          *
4428          * @param User $user
4429          * @return string|null
4430          */
4431         public function getNotificationTimestamp( $user = null ) {
4432                 global $wgUser;
4433
4434                 // Assume current user if none given
4435                 if ( !$user ) {
4436                         $user = $wgUser;
4437                 }
4438                 // Check cache first
4439                 $uid = $user->getId();
4440                 if ( !$uid ) {
4441                         return false;
4442                 }
4443                 // avoid isset here, as it'll return false for null entries
4444                 if ( array_key_exists( $uid, $this->mNotificationTimestamp ) ) {
4445                         return $this->mNotificationTimestamp[$uid];
4446                 }
4447                 // Don't cache too much!
4448                 if ( count( $this->mNotificationTimestamp ) >= self::CACHE_MAX ) {
4449                         $this->mNotificationTimestamp = [];
4450                 }
4451
4452                 $watchedItem = WatchedItemStore::getDefaultInstance()->getWatchedItem( $user, $this );
4453                 if ( $watchedItem ) {
4454                         $this->mNotificationTimestamp[$uid] = $watchedItem->getNotificationTimestamp();
4455                 } else {
4456                         $this->mNotificationTimestamp[$uid] = false;
4457                 }
4458
4459                 return $this->mNotificationTimestamp[$uid];
4460         }
4461
4462         /**
4463          * Generate strings used for xml 'id' names in monobook tabs
4464          *
4465          * @param string $prepend Defaults to 'nstab-'
4466          * @return string XML 'id' name
4467          */
4468         public function getNamespaceKey( $prepend = 'nstab-' ) {
4469                 global $wgContLang;
4470                 // Gets the subject namespace if this title
4471                 $namespace = MWNamespace::getSubject( $this->getNamespace() );
4472                 // Checks if canonical namespace name exists for namespace
4473                 if ( MWNamespace::exists( $this->getNamespace() ) ) {
4474                         // Uses canonical namespace name
4475                         $namespaceKey = MWNamespace::getCanonicalName( $namespace );
4476                 } else {
4477                         // Uses text of namespace
4478                         $namespaceKey = $this->getSubjectNsText();
4479                 }
4480                 // Makes namespace key lowercase
4481                 $namespaceKey = $wgContLang->lc( $namespaceKey );
4482                 // Uses main
4483                 if ( $namespaceKey == '' ) {
4484                         $namespaceKey = 'main';
4485                 }
4486                 // Changes file to image for backwards compatibility
4487                 if ( $namespaceKey == 'file' ) {
4488                         $namespaceKey = 'image';
4489                 }
4490                 return $prepend . $namespaceKey;
4491         }
4492
4493         /**
4494          * Get all extant redirects to this Title
4495          *
4496          * @param int|null $ns Single namespace to consider; null to consider all namespaces
4497          * @return Title[] Array of Title redirects to this title
4498          */
4499         public function getRedirectsHere( $ns = null ) {
4500                 $redirs = [];
4501
4502                 $dbr = wfGetDB( DB_SLAVE );
4503                 $where = [
4504                         'rd_namespace' => $this->getNamespace(),
4505                         'rd_title' => $this->getDBkey(),
4506                         'rd_from = page_id'
4507                 ];
4508                 if ( $this->isExternal() ) {
4509                         $where['rd_interwiki'] = $this->getInterwiki();
4510                 } else {
4511                         $where[] = 'rd_interwiki = ' . $dbr->addQuotes( '' ) . ' OR rd_interwiki IS NULL';
4512                 }
4513                 if ( !is_null( $ns ) ) {
4514                         $where['page_namespace'] = $ns;
4515                 }
4516
4517                 $res = $dbr->select(
4518                         [ 'redirect', 'page' ],
4519                         [ 'page_namespace', 'page_title' ],
4520                         $where,
4521                         __METHOD__
4522                 );
4523
4524                 foreach ( $res as $row ) {
4525                         $redirs[] = self::newFromRow( $row );
4526                 }
4527                 return $redirs;
4528         }
4529
4530         /**
4531          * Check if this Title is a valid redirect target
4532          *
4533          * @return bool
4534          */
4535         public function isValidRedirectTarget() {
4536                 global $wgInvalidRedirectTargets;
4537
4538                 if ( $this->isSpecialPage() ) {
4539                         // invalid redirect targets are stored in a global array, but explicitly disallow Userlogout here
4540                         if ( $this->isSpecial( 'Userlogout' ) ) {
4541                                 return false;
4542                         }
4543
4544                         foreach ( $wgInvalidRedirectTargets as $target ) {
4545                                 if ( $this->isSpecial( $target ) ) {
4546                                         return false;
4547                                 }
4548                         }
4549                 }
4550
4551                 return true;
4552         }
4553
4554         /**
4555          * Get a backlink cache object
4556          *
4557          * @return BacklinkCache
4558          */
4559         public function getBacklinkCache() {
4560                 return BacklinkCache::get( $this );
4561         }
4562
4563         /**
4564          * Whether the magic words __INDEX__ and __NOINDEX__ function for  this page.
4565          *
4566          * @return bool
4567          */
4568         public function canUseNoindex() {
4569                 global $wgContentNamespaces, $wgExemptFromUserRobotsControl;
4570
4571                 $bannedNamespaces = is_null( $wgExemptFromUserRobotsControl )
4572                         ? $wgContentNamespaces
4573                         : $wgExemptFromUserRobotsControl;
4574
4575                 return !in_array( $this->mNamespace, $bannedNamespaces );
4576
4577         }
4578
4579         /**
4580          * Returns the raw sort key to be used for categories, with the specified
4581          * prefix.  This will be fed to Collation::getSortKey() to get a
4582          * binary sortkey that can be used for actual sorting.
4583          *
4584          * @param string $prefix The prefix to be used, specified using
4585          *   {{defaultsort:}} or like [[Category:Foo|prefix]].  Empty for no
4586          *   prefix.
4587          * @return string
4588          */
4589         public function getCategorySortkey( $prefix = '' ) {
4590                 $unprefixed = $this->getText();
4591
4592                 // Anything that uses this hook should only depend
4593                 // on the Title object passed in, and should probably
4594                 // tell the users to run updateCollations.php --force
4595                 // in order to re-sort existing category relations.
4596                 Hooks::run( 'GetDefaultSortkey', [ $this, &$unprefixed ] );
4597                 if ( $prefix !== '' ) {
4598                         # Separate with a line feed, so the unprefixed part is only used as
4599                         # a tiebreaker when two pages have the exact same prefix.
4600                         # In UCA, tab is the only character that can sort above LF
4601                         # so we strip both of them from the original prefix.
4602                         $prefix = strtr( $prefix, "\n\t", '  ' );
4603                         return "$prefix\n$unprefixed";
4604                 }
4605                 return $unprefixed;
4606         }
4607
4608         /**
4609          * Returns the page language code saved in the database, if $wgPageLanguageUseDB is set
4610          * to true in LocalSettings.php, otherwise returns false. If there is no language saved in
4611          * the db, it will return NULL.
4612          *
4613          * @return string|null|bool
4614          */
4615         private function getDbPageLanguageCode() {
4616                 global $wgPageLanguageUseDB;
4617
4618                 // check, if the page language could be saved in the database, and if so and
4619                 // the value is not requested already, lookup the page language using LinkCache
4620                 if ( $wgPageLanguageUseDB && $this->mDbPageLanguage === false ) {
4621                         $linkCache = LinkCache::singleton();
4622                         $linkCache->addLinkObj( $this );
4623                         $this->mDbPageLanguage = $linkCache->getGoodLinkFieldObj( $this, 'lang' );
4624                 }
4625
4626                 return $this->mDbPageLanguage;
4627         }
4628
4629         /**
4630          * Get the language in which the content of this page is written in
4631          * wikitext. Defaults to $wgContLang, but in certain cases it can be
4632          * e.g. $wgLang (such as special pages, which are in the user language).
4633          *
4634          * @since 1.18
4635          * @return Language
4636          */
4637         public function getPageLanguage() {
4638                 global $wgLang, $wgLanguageCode;
4639                 if ( $this->isSpecialPage() ) {
4640                         // special pages are in the user language
4641                         return $wgLang;
4642                 }
4643
4644                 // Checking if DB language is set
4645                 $dbPageLanguage = $this->getDbPageLanguageCode();
4646                 if ( $dbPageLanguage ) {
4647                         return wfGetLangObj( $dbPageLanguage );
4648                 }
4649
4650                 if ( !$this->mPageLanguage || $this->mPageLanguage[1] !== $wgLanguageCode ) {
4651                         // Note that this may depend on user settings, so the cache should
4652                         // be only per-request.
4653                         // NOTE: ContentHandler::getPageLanguage() may need to load the
4654                         // content to determine the page language!
4655                         // Checking $wgLanguageCode hasn't changed for the benefit of unit
4656                         // tests.
4657                         $contentHandler = ContentHandler::getForTitle( $this );
4658                         $langObj = $contentHandler->getPageLanguage( $this );
4659                         $this->mPageLanguage = [ $langObj->getCode(), $wgLanguageCode ];
4660                 } else {
4661                         $langObj = wfGetLangObj( $this->mPageLanguage[0] );
4662                 }
4663
4664                 return $langObj;
4665         }
4666
4667         /**
4668          * Get the language in which the content of this page is written when
4669          * viewed by user. Defaults to $wgContLang, but in certain cases it can be
4670          * e.g. $wgLang (such as special pages, which are in the user language).
4671          *
4672          * @since 1.20
4673          * @return Language
4674          */
4675         public function getPageViewLanguage() {
4676                 global $wgLang;
4677
4678                 if ( $this->isSpecialPage() ) {
4679                         // If the user chooses a variant, the content is actually
4680                         // in a language whose code is the variant code.
4681                         $variant = $wgLang->getPreferredVariant();
4682                         if ( $wgLang->getCode() !== $variant ) {
4683                                 return Language::factory( $variant );
4684                         }
4685
4686                         return $wgLang;
4687                 }
4688
4689                 // Checking if DB language is set
4690                 $dbPageLanguage = $this->getDbPageLanguageCode();
4691                 if ( $dbPageLanguage ) {
4692                         $pageLang = wfGetLangObj( $dbPageLanguage );
4693                         $variant = $pageLang->getPreferredVariant();
4694                         if ( $pageLang->getCode() !== $variant ) {
4695                                 $pageLang = Language::factory( $variant );
4696                         }
4697
4698                         return $pageLang;
4699                 }
4700
4701                 // @note Can't be cached persistently, depends on user settings.
4702                 // @note ContentHandler::getPageViewLanguage() may need to load the
4703                 //   content to determine the page language!
4704                 $contentHandler = ContentHandler::getForTitle( $this );
4705                 $pageLang = $contentHandler->getPageViewLanguage( $this );
4706                 return $pageLang;
4707         }
4708
4709         /**
4710          * Get a list of rendered edit notices for this page.
4711          *
4712          * Array is keyed by the original message key, and values are rendered using parseAsBlock, so
4713          * they will already be wrapped in paragraphs.
4714          *
4715          * @since 1.21
4716          * @param int $oldid Revision ID that's being edited
4717          * @return array
4718          */
4719         public function getEditNotices( $oldid = 0 ) {
4720                 $notices = [];
4721
4722                 // Optional notice for the entire namespace
4723                 $editnotice_ns = 'editnotice-' . $this->getNamespace();
4724                 $msg = wfMessage( $editnotice_ns );
4725                 if ( $msg->exists() ) {
4726                         $html = $msg->parseAsBlock();
4727                         // Edit notices may have complex logic, but output nothing (T91715)
4728                         if ( trim( $html ) !== '' ) {
4729                                 $notices[$editnotice_ns] = Html::rawElement(
4730                                         'div',
4731                                         [ 'class' => [
4732                                                 'mw-editnotice',
4733                                                 'mw-editnotice-namespace',
4734                                                 Sanitizer::escapeClass( "mw-$editnotice_ns" )
4735                                         ] ],
4736                                         $html
4737                                 );
4738                         }
4739                 }
4740
4741                 if ( MWNamespace::hasSubpages( $this->getNamespace() ) ) {
4742                         // Optional notice for page itself and any parent page
4743                         $parts = explode( '/', $this->getDBkey() );
4744                         $editnotice_base = $editnotice_ns;
4745                         while ( count( $parts ) > 0 ) {
4746                                 $editnotice_base .= '-' . array_shift( $parts );
4747                                 $msg = wfMessage( $editnotice_base );
4748                                 if ( $msg->exists() ) {
4749                                         $html = $msg->parseAsBlock();
4750                                         if ( trim( $html ) !== '' ) {
4751                                                 $notices[$editnotice_base] = Html::rawElement(
4752                                                         'div',
4753                                                         [ 'class' => [
4754                                                                 'mw-editnotice',
4755                                                                 'mw-editnotice-base',
4756                                                                 Sanitizer::escapeClass( "mw-$editnotice_base" )
4757                                                         ] ],
4758                                                         $html
4759                                                 );
4760                                         }
4761                                 }
4762                         }
4763                 } else {
4764                         // Even if there are no subpages in namespace, we still don't want "/" in MediaWiki message keys
4765                         $editnoticeText = $editnotice_ns . '-' . strtr( $this->getDBkey(), '/', '-' );
4766                         $msg = wfMessage( $editnoticeText );
4767                         if ( $msg->exists() ) {
4768                                 $html = $msg->parseAsBlock();
4769                                 if ( trim( $html ) !== '' ) {
4770                                         $notices[$editnoticeText] = Html::rawElement(
4771                                                 'div',
4772                                                 [ 'class' => [
4773                                                         'mw-editnotice',
4774                                                         'mw-editnotice-page',
4775                                                         Sanitizer::escapeClass( "mw-$editnoticeText" )
4776                                                 ] ],
4777                                                 $html
4778                                         );
4779                                 }
4780                         }
4781                 }
4782
4783                 Hooks::run( 'TitleGetEditNotices', [ $this, $oldid, &$notices ] );
4784                 return $notices;
4785         }
4786
4787         /**
4788          * @return array
4789          */
4790         public function __sleep() {
4791                 return [
4792                         'mNamespace',
4793                         'mDbkeyform',
4794                         'mFragment',
4795                         'mInterwiki',
4796                         'mLocalInterwiki',
4797                         'mUserCaseDBKey',
4798                         'mDefaultNamespace',
4799                 ];
4800         }
4801
4802         public function __wakeup() {
4803                 $this->mArticleID = ( $this->mNamespace >= 0 ) ? -1 : 0;
4804                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
4805                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
4806         }
4807
4808 }