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|boolean|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 only return the very next target, useful for
 579          * the redirect table and other checks that don't need full recursion
 580          *
 581          * @param string $text Text with possible redirect
 582          * @return Title The corresponding Title
 583          * @deprecated since 1.21, use Content::getRedirectTarget instead.
 584          */
 585         public static function newFromRedirect( $text ) {
 586                 ContentHandler::deprecated( __METHOD__, '1.21' );
 587
 588                 $content = ContentHandler::makeContent( $text, null, CONTENT_MODEL_WIKITEXT );
 589                 return $content->getRedirectTarget();
 590         }
 591
 592         /**
 593          * Extract a redirect destination from a string and return the
 594          * Title, or null if the text doesn't contain a valid redirect
 595          * This will recurse down $wgMaxRedirects times or until a non-redirect target is hit
 596          * in order to provide (hopefully) the Title of the final destination instead of another redirect
 597          *
 598          * @param string $text Text with possible redirect
 599          * @return Title
 600          * @deprecated since 1.21, use Content::getUltimateRedirectTarget instead.
 601          */
 602         public static function newFromRedirectRecurse( $text ) {
 603                 ContentHandler::deprecated( __METHOD__, '1.21' );
 604
 605                 $content = ContentHandler::makeContent( $text, null, CONTENT_MODEL_WIKITEXT );
 606                 return $content->getUltimateRedirectTarget();
 607         }
 608
 609         /**
 610          * Extract a redirect destination from a string and return an
 611          * array of Titles, or null if the text doesn't contain a valid redirect
 612          * The last element in the array is the final destination after all redirects
 613          * have been resolved (up to $wgMaxRedirects times)
 614          *
 615          * @param string $text Text with possible redirect
 616          * @return Title[] Array of Titles, with the destination last
 617          * @deprecated since 1.21, use Content::getRedirectChain instead.
 618          */
 619         public static function newFromRedirectArray( $text ) {
 620                 ContentHandler::deprecated( __METHOD__, '1.21' );
 621
 622                 $content = ContentHandler::makeContent( $text, null, CONTENT_MODEL_WIKITEXT );
 623                 return $content->getRedirectChain();
 624         }
 625
 626         /**
 627          * Get the prefixed DB key associated with an ID
 628          *
 629          * @param int $id The page_id of the article
 630          * @return Title|null An object representing the article, or null if no such article was found
 631          */
 632         public static function nameOf( $id ) {
 633                 $dbr = wfGetDB( DB_SLAVE );
 634
 635                 $s = $dbr->selectRow(
 636                         'page',
 637                         [ 'page_namespace', 'page_title' ],
 638                         [ 'page_id' => $id ],
 639                         __METHOD__
 640                 );
 641                 if ( $s === false ) {
 642                         return null;
 643                 }
 644
 645                 $n = self::makeName( $s->page_namespace, $s->page_title );
 646                 return $n;
 647         }
 648
 649         /**
 650          * Get a regex character class describing the legal characters in a link
 651          *
 652          * @return string The list of characters, not delimited
 653          */
 654         public static function legalChars() {
 655                 global $wgLegalTitleChars;
 656                 return $wgLegalTitleChars;
 657         }
 658
 659         /**
 660          * Returns a simple regex that will match on characters and sequences invalid in titles.
 661          * Note that this doesn't pick up many things that could be wrong with titles, but that
 662          * replacing this regex with something valid will make many titles valid.
 663          *
 664          * @deprecated since 1.25, use MediaWikiTitleCodec::getTitleInvalidRegex() instead
 665          *
 666          * @return string Regex string
 667          */
 668         static function getTitleInvalidRegex() {
 669                 wfDeprecated( __METHOD__, '1.25' );
 670                 return MediaWikiTitleCodec::getTitleInvalidRegex();
 671         }
 672
 673         /**
 674          * Utility method for converting a character sequence from bytes to Unicode.
 675          *
 676          * Primary usecase being converting $wgLegalTitleChars to a sequence usable in
 677          * javascript, as PHP uses UTF-8 bytes where javascript uses Unicode code units.
 678          *
 679          * @param string $byteClass
 680          * @return string
 681          */
 682         public static function convertByteClassToUnicodeClass( $byteClass ) {
 683                 $length = strlen( $byteClass );
 684                 // Input token queue
 685                 $x0 = $x1 = $x2 = '';
 686                 // Decoded queue
 687                 $d0 = $d1 = $d2 = '';
 688                 // Decoded integer codepoints
 689                 $ord0 = $ord1 = $ord2 = 0;
 690                 // Re-encoded queue
 691                 $r0 = $r1 = $r2 = '';
 692                 // Output
 693                 $out = '';
 694                 // Flags
 695                 $allowUnicode = false;
 696                 for ( $pos = 0; $pos < $length; $pos++ ) {
 697                         // Shift the queues down
 698                         $x2 = $x1;
 699                         $x1 = $x0;
 700                         $d2 = $d1;
 701                         $d1 = $d0;
 702                         $ord2 = $ord1;
 703                         $ord1 = $ord0;
 704                         $r2 = $r1;
 705                         $r1 = $r0;
 706                         // Load the current input token and decoded values
 707                         $inChar = $byteClass[$pos];
 708                         if ( $inChar == '\\' ) {
 709                                 if ( preg_match( '/x([0-9a-fA-F]{2})/A', $byteClass, $m, 0, $pos + 1 ) ) {
 710                                         $x0 = $inChar . $m[0];
 711                                         $d0 = chr( hexdec( $m[1] ) );
 712                                         $pos += strlen( $m[0] );
 713                                 } elseif ( preg_match( '/[0-7]{3}/A', $byteClass, $m, 0, $pos + 1 ) ) {
 714                                         $x0 = $inChar . $m[0];
 715                                         $d0 = chr( octdec( $m[0] ) );
 716                                         $pos += strlen( $m[0] );
 717                                 } elseif ( $pos + 1 >= $length ) {
 718                                         $x0 = $d0 = '\\';
 719                                 } else {
 720                                         $d0 = $byteClass[$pos + 1];
 721                                         $x0 = $inChar . $d0;
 722                                         $pos += 1;
 723                                 }
 724                         } else {
 725                                 $x0 = $d0 = $inChar;
 726                         }
 727                         $ord0 = ord( $d0 );
 728                         // Load the current re-encoded value
 729                         if ( $ord0 < 32 || $ord0 == 0x7f ) {
 730                                 $r0 = sprintf( '\x%02x', $ord0 );
 731                         } elseif ( $ord0 >= 0x80 ) {
 732                                 // Allow unicode if a single high-bit character appears
 733                                 $r0 = sprintf( '\x%02x', $ord0 );
 734                                 $allowUnicode = true;
 735                         } elseif ( strpos( '-\\[]^', $d0 ) !== false ) {
 736                                 $r0 = '\\' . $d0;
 737                         } else {
 738                                 $r0 = $d0;
 739                         }
 740                         // Do the output
 741                         if ( $x0 !== '' && $x1 === '-' && $x2 !== '' ) {
 742                                 // Range
 743                                 if ( $ord2 > $ord0 ) {
 744                                         // Empty range
 745                                 } elseif ( $ord0 >= 0x80 ) {
 746                                         // Unicode range
 747                                         $allowUnicode = true;
 748                                         if ( $ord2 < 0x80 ) {
 749                                                 // Keep the non-unicode section of the range
 750                                                 $out .= "$r2-\\x7F";
 751                                         }
 752                                 } else {
 753                                         // Normal range
 754                                         $out .= "$r2-$r0";
 755                                 }
 756                                 // Reset state to the initial value
 757                                 $x0 = $x1 = $d0 = $d1 = $r0 = $r1 = '';
 758                         } elseif ( $ord2 < 0x80 ) {
 759                                 // ASCII character
 760                                 $out .= $r2;
 761                         }
 762                 }
 763                 if ( $ord1 < 0x80 ) {
 764                         $out .= $r1;
 765                 }
 766                 if ( $ord0 < 0x80 ) {
 767                         $out .= $r0;
 768                 }
 769                 if ( $allowUnicode ) {
 770                         $out .= '\u0080-\uFFFF';
 771                 }
 772                 return $out;
 773         }
 774
 775         /**
 776          * Make a prefixed DB key from a DB key and a namespace index
 777          *
 778          * @param int $ns Numerical representation of the namespace
 779          * @param string $title The DB key form the title
 780          * @param string $fragment The link fragment (after the "#")
 781          * @param string $interwiki The interwiki prefix
 782          * @param bool $canonicalNamespace If true, use the canonical name for
 783          *   $ns instead of the localized version.
 784          * @return string The prefixed form of the title
 785          */
 786         public static function makeName( $ns, $title, $fragment = '', $interwiki = '',
 787                 $canonicalNamespace = false
 788         ) {
 789                 global $wgContLang;
 790
 791                 if ( $canonicalNamespace ) {
 792                         $namespace = MWNamespace::getCanonicalName( $ns );
 793                 } else {
 794                         $namespace = $wgContLang->getNsText( $ns );
 795                 }
 796                 $name = $namespace == '' ? $title : "$namespace:$title";
 797                 if ( strval( $interwiki ) != '' ) {
 798                         $name = "$interwiki:$name";
 799                 }
 800                 if ( strval( $fragment ) != '' ) {
 801                         $name .= '#' . $fragment;
 802                 }
 803                 return $name;
 804         }
 805
 806         /**
 807          * Escape a text fragment, say from a link, for a URL
 808          *
 809          * @param string $fragment Containing a URL or link fragment (after the "#")
 810          * @return string Escaped string
 811          */
 812         static function escapeFragmentForURL( $fragment ) {
 813                 # Note that we don't urlencode the fragment.  urlencoded Unicode
 814                 # fragments appear not to work in IE (at least up to 7) or in at least
 815                 # one version of Opera 9.x.  The W3C validator, for one, doesn't seem
 816                 # to care if they aren't encoded.
 817                 return Sanitizer::escapeId( $fragment, 'noninitial' );
 818         }
 819
 820         /**
 821          * Callback for usort() to do title sorts by (namespace, title)
 822          *
 823          * @param Title $a
 824          * @param Title $b
 825          *
 826          * @return int Result of string comparison, or namespace comparison
 827          */
 828         public static function compare( $a, $b ) {
 829                 if ( $a->getNamespace() == $b->getNamespace() ) {
 830                         return strcmp( $a->getText(), $b->getText() );
 831                 } else {
 832                         return $a->getNamespace() - $b->getNamespace();
 833                 }
 834         }
 835
 836         /**
 837          * Determine whether the object refers to a page within
 838          * this project (either this wiki or a wiki with a local
 839          * interwiki, see https://www.mediawiki.org/wiki/Manual:Interwiki_table#iw_local )
 840          *
 841          * @return bool True if this is an in-project interwiki link or a wikilink, false otherwise
 842          */
 843         public function isLocal() {
 844                 if ( $this->isExternal() ) {
 845                         $iw = Interwiki::fetch( $this->mInterwiki );
 846                         if ( $iw ) {
 847                                 return $iw->isLocal();
 848                         }
 849                 }
 850                 return true;
 851         }
 852
 853         /**
 854          * Is this Title interwiki?
 855          *
 856          * @return bool
 857          */
 858         public function isExternal() {
 859                 return $this->mInterwiki !== '';
 860         }
 861
 862         /**
 863          * Get the interwiki prefix
 864          *
 865          * Use Title::isExternal to check if a interwiki is set
 866          *
 867          * @return string Interwiki prefix
 868          */
 869         public function getInterwiki() {
 870                 return $this->mInterwiki;
 871         }
 872
 873         /**
 874          * Was this a local interwiki link?
 875          *
 876          * @return bool
 877          */
 878         public function wasLocalInterwiki() {
 879                 return $this->mLocalInterwiki;
 880         }
 881
 882         /**
 883          * Determine whether the object refers to a page within
 884          * this project and is transcludable.
 885          *
 886          * @return bool True if this is transcludable
 887          */
 888         public function isTrans() {
 889                 if ( !$this->isExternal() ) {
 890                         return false;
 891                 }
 892
 893                 return Interwiki::fetch( $this->mInterwiki )->isTranscludable();
 894         }
 895
 896         /**
 897          * Returns the DB name of the distant wiki which owns the object.
 898          *
 899          * @return string The DB name
 900          */
 901         public function getTransWikiID() {
 902                 if ( !$this->isExternal() ) {
 903                         return false;
 904                 }
 905
 906                 return Interwiki::fetch( $this->mInterwiki )->getWikiID();
 907         }
 908
 909         /**
 910          * Get a TitleValue object representing this Title.
 911          *
 912          * @note Not all valid Titles have a corresponding valid TitleValue
 913          * (e.g. TitleValues cannot represent page-local links that have a
 914          * fragment but no title text).
 915          *
 916          * @return TitleValue|null
 917          */
 918         public function getTitleValue() {
 919                 if ( $this->mTitleValue === null ) {
 920                         try {
 921                                 $this->mTitleValue = new TitleValue(
 922                                         $this->getNamespace(),
 923                                         $this->getDBkey(),
 924                                         $this->getFragment() );
 925                         } catch ( InvalidArgumentException $ex ) {
 926                                 wfDebug( __METHOD__ . ': Can\'t create a TitleValue for [[' .
 927                                         $this->getPrefixedText() . ']]: ' . $ex->getMessage() . "\n" );
 928                         }
 929                 }
 930
 931                 return $this->mTitleValue;
 932         }
 933
 934         /**
 935          * Get the text form (spaces not underscores) of the main part
 936          *
 937          * @return string Main part of the title
 938          */
 939         public function getText() {
 940                 return $this->mTextform;
 941         }
 942
 943         /**
 944          * Get the URL-encoded form of the main part
 945          *
 946          * @return string Main part of the title, URL-encoded
 947          */
 948         public function getPartialURL() {
 949                 return $this->mUrlform;
 950         }
 951
 952         /**
 953          * Get the main part with underscores
 954          *
 955          * @return string Main part of the title, with underscores
 956          */
 957         public function getDBkey() {
 958                 return $this->mDbkeyform;
 959         }
 960
 961         /**
 962          * Get the DB key with the initial letter case as specified by the user
 963          *
 964          * @return string DB key
 965          */
 966         function getUserCaseDBKey() {
 967                 if ( !is_null( $this->mUserCaseDBKey ) ) {
 968                         return $this->mUserCaseDBKey;
 969                 } else {
 970                         // If created via makeTitle(), $this->mUserCaseDBKey is not set.
 971                         return $this->mDbkeyform;
 972                 }
 973         }
 974
 975         /**
 976          * Get the namespace index, i.e. one of the NS_xxxx constants.
 977          *
 978          * @return int Namespace index
 979          */
 980         public function getNamespace() {
 981                 return $this->mNamespace;
 982         }
 983
 984         /**
 985          * Get the page's content model id, see the CONTENT_MODEL_XXX constants.
 986          *
 987          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
 988          * @return string Content model id
 989          */
 990         public function getContentModel( $flags = 0 ) {
 991                 if ( !$this->mContentModel && $this->getArticleID( $flags ) ) {
 992                         $linkCache = LinkCache::singleton();
 993                         $linkCache->addLinkObj( $this ); # in case we already had an article ID
 994                         $this->mContentModel = $linkCache->getGoodLinkFieldObj( $this, 'model' );
 995                 }
 996
 997                 if ( !$this->mContentModel ) {
 998                         $this->mContentModel = ContentHandler::getDefaultModelFor( $this );
 999                 }
1000
1001                 return $this->mContentModel;
1002         }
1003
1004         /**
1005          * Convenience method for checking a title's content model name
1006          *
1007          * @param string $id The content model ID (use the CONTENT_MODEL_XXX constants).
1008          * @return bool True if $this->getContentModel() == $id
1009          */
1010         public function hasContentModel( $id ) {
1011                 return $this->getContentModel() == $id;
1012         }
1013
1014         /**
1015          * Get the namespace text
1016          *
1017          * @return string Namespace text
1018          */
1019         public function getNsText() {
1020                 if ( $this->isExternal() ) {
1021                         // This probably shouldn't even happen,
1022                         // but for interwiki transclusion it sometimes does.
1023                         // Use the canonical namespaces if possible to try to
1024                         // resolve a foreign namespace.
1025                         if ( MWNamespace::exists( $this->mNamespace ) ) {
1026                                 return MWNamespace::getCanonicalName( $this->mNamespace );
1027                         }
1028                 }
1029
1030                 try {
1031                         $formatter = self::getTitleFormatter();
1032                         return $formatter->getNamespaceName( $this->mNamespace, $this->mDbkeyform );
1033                 } catch ( InvalidArgumentException $ex ) {
1034                         wfDebug( __METHOD__ . ': ' . $ex->getMessage() . "\n" );
1035                         return false;
1036                 }
1037         }
1038
1039         /**
1040          * Get the namespace text of the subject (rather than talk) page
1041          *
1042          * @return string Namespace text
1043          */
1044         public function getSubjectNsText() {
1045                 global $wgContLang;
1046                 return $wgContLang->getNsText( MWNamespace::getSubject( $this->mNamespace ) );
1047         }
1048
1049         /**
1050          * Get the namespace text of the talk page
1051          *
1052          * @return string Namespace text
1053          */
1054         public function getTalkNsText() {
1055                 global $wgContLang;
1056                 return $wgContLang->getNsText( MWNamespace::getTalk( $this->mNamespace ) );
1057         }
1058
1059         /**
1060          * Could this title have a corresponding talk page?
1061          *
1062          * @return bool
1063          */
1064         public function canTalk() {
1065                 return MWNamespace::canTalk( $this->mNamespace );
1066         }
1067
1068         /**
1069          * Is this in a namespace that allows actual pages?
1070          *
1071          * @return bool
1072          */
1073         public function canExist() {
1074                 return $this->mNamespace >= NS_MAIN;
1075         }
1076
1077         /**
1078          * Can this title be added to a user's watchlist?
1079          *
1080          * @return bool
1081          */
1082         public function isWatchable() {
1083                 return !$this->isExternal() && MWNamespace::isWatchable( $this->getNamespace() );
1084         }
1085
1086         /**
1087          * Returns true if this is a special page.
1088          *
1089          * @return bool
1090          */
1091         public function isSpecialPage() {
1092                 return $this->getNamespace() == NS_SPECIAL;
1093         }
1094
1095         /**
1096          * Returns true if this title resolves to the named special page
1097          *
1098          * @param string $name The special page name
1099          * @return bool
1100          */
1101         public function isSpecial( $name ) {
1102                 if ( $this->isSpecialPage() ) {
1103                         list( $thisName, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $this->getDBkey() );
1104                         if ( $name == $thisName ) {
1105                                 return true;
1106                         }
1107                 }
1108                 return false;
1109         }
1110
1111         /**
1112          * If the Title refers to a special page alias which is not the local default, resolve
1113          * the alias, and localise the name as necessary.  Otherwise, return $this
1114          *
1115          * @return Title
1116          */
1117         public function fixSpecialName() {
1118                 if ( $this->isSpecialPage() ) {
1119                         list( $canonicalName, $par ) = SpecialPageFactory::resolveAlias( $this->mDbkeyform );
1120                         if ( $canonicalName ) {
1121                                 $localName = SpecialPageFactory::getLocalNameFor( $canonicalName, $par );
1122                                 if ( $localName != $this->mDbkeyform ) {
1123                                         return Title::makeTitle( NS_SPECIAL, $localName );
1124                                 }
1125                         }
1126                 }
1127                 return $this;
1128         }
1129
1130         /**
1131          * Returns true if the title is inside the specified namespace.
1132          *
1133          * Please make use of this instead of comparing to getNamespace()
1134          * This function is much more resistant to changes we may make
1135          * to namespaces than code that makes direct comparisons.
1136          * @param int $ns The namespace
1137          * @return bool
1138          * @since 1.19
1139          */
1140         public function inNamespace( $ns ) {
1141                 return MWNamespace::equals( $this->getNamespace(), $ns );
1142         }
1143
1144         /**
1145          * Returns true if the title is inside one of the specified namespaces.
1146          *
1147          * @param int $namespaces,... The namespaces to check for
1148          * @return bool
1149          * @since 1.19
1150          */
1151         public function inNamespaces( /* ... */ ) {
1152                 $namespaces = func_get_args();
1153                 if ( count( $namespaces ) > 0 && is_array( $namespaces[0] ) ) {
1154                         $namespaces = $namespaces[0];
1155                 }
1156
1157                 foreach ( $namespaces as $ns ) {
1158                         if ( $this->inNamespace( $ns ) ) {
1159                                 return true;
1160                         }
1161                 }
1162
1163                 return false;
1164         }
1165
1166         /**
1167          * Returns true if the title has the same subject namespace as the
1168          * namespace specified.
1169          * For example this method will take NS_USER and return true if namespace
1170          * is either NS_USER or NS_USER_TALK since both of them have NS_USER
1171          * as their subject namespace.
1172          *
1173          * This is MUCH simpler than individually testing for equivalence
1174          * against both NS_USER and NS_USER_TALK, and is also forward compatible.
1175          * @since 1.19
1176          * @param int $ns
1177          * @return bool
1178          */
1179         public function hasSubjectNamespace( $ns ) {
1180                 return MWNamespace::subjectEquals( $this->getNamespace(), $ns );
1181         }
1182
1183         /**
1184          * Is this Title in a namespace which contains content?
1185          * In other words, is this a content page, for the purposes of calculating
1186          * statistics, etc?
1187          *
1188          * @return bool
1189          */
1190         public function isContentPage() {
1191                 return MWNamespace::isContent( $this->getNamespace() );
1192         }
1193
1194         /**
1195          * Would anybody with sufficient privileges be able to move this page?
1196          * Some pages just aren't movable.
1197          *
1198          * @return bool
1199          */
1200         public function isMovable() {
1201                 if ( !MWNamespace::isMovable( $this->getNamespace() ) || $this->isExternal() ) {
1202                         // Interwiki title or immovable namespace. Hooks don't get to override here
1203                         return false;
1204                 }
1205
1206                 $result = true;
1207                 Hooks::run( 'TitleIsMovable', [ $this, &$result ] );
1208                 return $result;
1209         }
1210
1211         /**
1212          * Is this the mainpage?
1213          * @note Title::newFromText seems to be sufficiently optimized by the title
1214          * cache that we don't need to over-optimize by doing direct comparisons and
1215          * accidentally creating new bugs where $title->equals( Title::newFromText() )
1216          * ends up reporting something differently than $title->isMainPage();
1217          *
1218          * @since 1.18
1219          * @return bool
1220          */
1221         public function isMainPage() {
1222                 return $this->equals( Title::newMainPage() );
1223         }
1224
1225         /**
1226          * Is this a subpage?
1227          *
1228          * @return bool
1229          */
1230         public function isSubpage() {
1231                 return MWNamespace::hasSubpages( $this->mNamespace )
1232                         ? strpos( $this->getText(), '/' ) !== false
1233                         : false;
1234         }
1235
1236         /**
1237          * Is this a conversion table for the LanguageConverter?
1238          *
1239          * @return bool
1240          */
1241         public function isConversionTable() {
1242                 // @todo ConversionTable should become a separate content model.
1243
1244                 return $this->getNamespace() == NS_MEDIAWIKI &&
1245                         strpos( $this->getText(), 'Conversiontable/' ) === 0;
1246         }
1247
1248         /**
1249          * Does that page contain wikitext, or it is JS, CSS or whatever?
1250          *
1251          * @return bool
1252          */
1253         public function isWikitextPage() {
1254                 return $this->hasContentModel( CONTENT_MODEL_WIKITEXT );
1255         }
1256
1257         /**
1258          * Could this page contain custom CSS or JavaScript for the global UI.
1259          * This is generally true for pages in the MediaWiki namespace having CONTENT_MODEL_CSS
1260          * or CONTENT_MODEL_JAVASCRIPT.
1261          *
1262          * This method does *not* return true for per-user JS/CSS. Use isCssJsSubpage()
1263          * for that!
1264          *
1265          * Note that this method should not return true for pages that contain and
1266          * show "inactive" CSS or JS.
1267          *
1268          * @return bool
1269          * @todo FIXME: Rename to isSiteConfigPage() and remove deprecated hook
1270          */
1271         public function isCssOrJsPage() {
1272                 $isCssOrJsPage = NS_MEDIAWIKI == $this->mNamespace
1273                         && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1274                                 || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1275
1276                 # @note This hook is also called in ContentHandler::getDefaultModel.
1277                 #   It's called here again to make sure hook functions can force this
1278                 #   method to return true even outside the MediaWiki namespace.
1279
1280                 Hooks::run( 'TitleIsCssOrJsPage', [ $this, &$isCssOrJsPage ], '1.25' );
1281
1282                 return $isCssOrJsPage;
1283         }
1284
1285         /**
1286          * Is this a .css or .js subpage of a user page?
1287          * @return bool
1288          * @todo FIXME: Rename to isUserConfigPage()
1289          */
1290         public function isCssJsSubpage() {
1291                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1292                                 && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1293                                         || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) ) );
1294         }
1295
1296         /**
1297          * Trim down a .css or .js subpage title to get the corresponding skin name
1298          *
1299          * @return string Containing skin name from .css or .js subpage title
1300          */
1301         public function getSkinFromCssJsSubpage() {
1302                 $subpage = explode( '/', $this->mTextform );
1303                 $subpage = $subpage[count( $subpage ) - 1];
1304                 $lastdot = strrpos( $subpage, '.' );
1305                 if ( $lastdot === false ) {
1306                         return $subpage; # Never happens: only called for names ending in '.css' or '.js'
1307                 }
1308                 return substr( $subpage, 0, $lastdot );
1309         }
1310
1311         /**
1312          * Is this a .css subpage of a user page?
1313          *
1314          * @return bool
1315          */
1316         public function isCssSubpage() {
1317                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1318                         && $this->hasContentModel( CONTENT_MODEL_CSS ) );
1319         }
1320
1321         /**
1322          * Is this a .js subpage of a user page?
1323          *
1324          * @return bool
1325          */
1326         public function isJsSubpage() {
1327                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1328                         && $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1329         }
1330
1331         /**
1332          * Is this a talk page of some sort?
1333          *
1334          * @return bool
1335          */
1336         public function isTalkPage() {
1337                 return MWNamespace::isTalk( $this->getNamespace() );
1338         }
1339
1340         /**
1341          * Get a Title object associated with the talk page of this article
1342          *
1343          * @return Title The object for the talk page
1344          */
1345         public function getTalkPage() {
1346                 return Title::makeTitle( MWNamespace::getTalk( $this->getNamespace() ), $this->getDBkey() );
1347         }
1348
1349         /**
1350          * Get a title object associated with the subject page of this
1351          * talk page
1352          *
1353          * @return Title The object for the subject page
1354          */
1355         public function getSubjectPage() {
1356                 // Is this the same title?
1357                 $subjectNS = MWNamespace::getSubject( $this->getNamespace() );
1358                 if ( $this->getNamespace() == $subjectNS ) {
1359                         return $this;
1360                 }
1361                 return Title::makeTitle( $subjectNS, $this->getDBkey() );
1362         }
1363
1364         /**
1365          * Get the other title for this page, if this is a subject page
1366          * get the talk page, if it is a subject page get the talk page
1367          *
1368          * @since 1.25
1369          * @throws MWException
1370          * @return Title
1371          */
1372         public function getOtherPage() {
1373                 if ( $this->isSpecialPage() ) {
1374                         throw new MWException( 'Special pages cannot have other pages' );
1375                 }
1376                 if ( $this->isTalkPage() ) {
1377                         return $this->getSubjectPage();
1378                 } else {
1379                         return $this->getTalkPage();
1380                 }
1381         }
1382
1383         /**
1384          * Get the default namespace index, for when there is no namespace
1385          *
1386          * @return int Default namespace index
1387          */
1388         public function getDefaultNamespace() {
1389                 return $this->mDefaultNamespace;
1390         }
1391
1392         /**
1393          * Get the Title fragment (i.e.\ the bit after the #) in text form
1394          *
1395          * Use Title::hasFragment to check for a fragment
1396          *
1397          * @return string Title fragment
1398          */
1399         public function getFragment() {
1400                 return $this->mFragment;
1401         }
1402
1403         /**
1404          * Check if a Title fragment is set
1405          *
1406          * @return bool
1407          * @since 1.23
1408          */
1409         public function hasFragment() {
1410                 return $this->mFragment !== '';
1411         }
1412
1413         /**
1414          * Get the fragment in URL form, including the "#" character if there is one
1415          * @return string Fragment in URL form
1416          */
1417         public function getFragmentForURL() {
1418                 if ( !$this->hasFragment() ) {
1419                         return '';
1420                 } else {
1421                         return '#' . Title::escapeFragmentForURL( $this->getFragment() );
1422                 }
1423         }
1424
1425         /**
1426          * Set the fragment for this title. Removes the first character from the
1427          * specified fragment before setting, so it assumes you're passing it with
1428          * an initial "#".
1429          *
1430          * Deprecated for public use, use Title::makeTitle() with fragment parameter.
1431          * Still in active use privately.
1432          *
1433          * @private
1434          * @param string $fragment Text
1435          */
1436         public function setFragment( $fragment ) {
1437                 $this->mFragment = strtr( substr( $fragment, 1 ), '_', ' ' );
1438         }
1439
1440         /**
1441          * Prefix some arbitrary text with the namespace or interwiki prefix
1442          * of this object
1443          *
1444          * @param string $name The text
1445          * @return string The prefixed text
1446          */
1447         private function prefix( $name ) {
1448                 $p = '';
1449                 if ( $this->isExternal() ) {
1450                         $p = $this->mInterwiki . ':';
1451                 }
1452
1453                 if ( 0 != $this->mNamespace ) {
1454                         $p .= $this->getNsText() . ':';
1455                 }
1456                 return $p . $name;
1457         }
1458
1459         /**
1460          * Get the prefixed database key form
1461          *
1462          * @return string The prefixed title, with underscores and
1463          *  any interwiki and namespace prefixes
1464          */
1465         public function getPrefixedDBkey() {
1466                 $s = $this->prefix( $this->mDbkeyform );
1467                 $s = strtr( $s, ' ', '_' );
1468                 return $s;
1469         }
1470
1471         /**
1472          * Get the prefixed title with spaces.
1473          * This is the form usually used for display
1474          *
1475          * @return string The prefixed title, with spaces
1476          */
1477         public function getPrefixedText() {
1478                 if ( $this->mPrefixedText === null ) {
1479                         $s = $this->prefix( $this->mTextform );
1480                         $s = strtr( $s, '_', ' ' );
1481                         $this->mPrefixedText = $s;
1482                 }
1483                 return $this->mPrefixedText;
1484         }
1485
1486         /**
1487          * Return a string representation of this title
1488          *
1489          * @return string Representation of this title
1490          */
1491         public function __toString() {
1492                 return $this->getPrefixedText();
1493         }
1494
1495         /**
1496          * Get the prefixed title with spaces, plus any fragment
1497          * (part beginning with '#')
1498          *
1499          * @return string The prefixed title, with spaces and the fragment, including '#'
1500          */
1501         public function getFullText() {
1502                 $text = $this->getPrefixedText();
1503                 if ( $this->hasFragment() ) {
1504                         $text .= '#' . $this->getFragment();
1505                 }
1506                 return $text;
1507         }
1508
1509         /**
1510          * Get the root page name text without a namespace, i.e. the leftmost part before any slashes
1511          *
1512          * @par Example:
1513          * @code
1514          * Title::newFromText('User:Foo/Bar/Baz')->getRootText();
1515          * # returns: 'Foo'
1516          * @endcode
1517          *
1518          * @return string Root name
1519          * @since 1.20
1520          */
1521         public function getRootText() {
1522                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1523                         return $this->getText();
1524                 }
1525
1526                 return strtok( $this->getText(), '/' );
1527         }
1528
1529         /**
1530          * Get the root page name title, i.e. the leftmost part before any slashes
1531          *
1532          * @par Example:
1533          * @code
1534          * Title::newFromText('User:Foo/Bar/Baz')->getRootTitle();
1535          * # returns: Title{User:Foo}
1536          * @endcode
1537          *
1538          * @return Title Root title
1539          * @since 1.20
1540          */
1541         public function getRootTitle() {
1542                 return Title::makeTitle( $this->getNamespace(), $this->getRootText() );
1543         }
1544
1545         /**
1546          * Get the base page name without a namespace, i.e. the part before the subpage name
1547          *
1548          * @par Example:
1549          * @code
1550          * Title::newFromText('User:Foo/Bar/Baz')->getBaseText();
1551          * # returns: 'Foo/Bar'
1552          * @endcode
1553          *
1554          * @return string Base name
1555          */
1556         public function getBaseText() {
1557                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1558                         return $this->getText();
1559                 }
1560
1561                 $parts = explode( '/', $this->getText() );
1562                 # Don't discard the real title if there's no subpage involved
1563                 if ( count( $parts ) > 1 ) {
1564                         unset( $parts[count( $parts ) - 1] );
1565                 }
1566                 return implode( '/', $parts );
1567         }
1568
1569         /**
1570          * Get the base page name title, i.e. the part before the subpage name
1571          *
1572          * @par Example:
1573          * @code
1574          * Title::newFromText('User:Foo/Bar/Baz')->getBaseTitle();
1575          * # returns: Title{User:Foo/Bar}
1576          * @endcode
1577          *
1578          * @return Title Base title
1579          * @since 1.20
1580          */
1581         public function getBaseTitle() {
1582                 return Title::makeTitle( $this->getNamespace(), $this->getBaseText() );
1583         }
1584
1585         /**
1586          * Get the lowest-level subpage name, i.e. the rightmost part after any slashes
1587          *
1588          * @par Example:
1589          * @code
1590          * Title::newFromText('User:Foo/Bar/Baz')->getSubpageText();
1591          * # returns: "Baz"
1592          * @endcode
1593          *
1594          * @return string Subpage name
1595          */
1596         public function getSubpageText() {
1597                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1598                         return $this->mTextform;
1599                 }
1600                 $parts = explode( '/', $this->mTextform );
1601                 return $parts[count( $parts ) - 1];
1602         }
1603
1604         /**
1605          * Get the title for a subpage of the current page
1606          *
1607          * @par Example:
1608          * @code
1609          * Title::newFromText('User:Foo/Bar/Baz')->getSubpage("Asdf");
1610          * # returns: Title{User:Foo/Bar/Baz/Asdf}
1611          * @endcode
1612          *
1613          * @param string $text The subpage name to add to the title
1614          * @return Title Subpage title
1615          * @since 1.20
1616          */
1617         public function getSubpage( $text ) {
1618                 return Title::makeTitleSafe( $this->getNamespace(), $this->getText() . '/' . $text );
1619         }
1620
1621         /**
1622          * Get a URL-encoded form of the subpage text
1623          *
1624          * @return string URL-encoded subpage name
1625          */
1626         public function getSubpageUrlForm() {
1627                 $text = $this->getSubpageText();
1628                 $text = wfUrlencode( strtr( $text, ' ', '_' ) );
1629                 return $text;
1630         }
1631
1632         /**
1633          * Get a URL-encoded title (not an actual URL) including interwiki
1634          *
1635          * @return string The URL-encoded form
1636          */
1637         public function getPrefixedURL() {
1638                 $s = $this->prefix( $this->mDbkeyform );
1639                 $s = wfUrlencode( strtr( $s, ' ', '_' ) );
1640                 return $s;
1641         }
1642
1643         /**
1644          * Helper to fix up the get{Canonical,Full,Link,Local,Internal}URL args
1645          * get{Canonical,Full,Link,Local,Internal}URL methods accepted an optional
1646          * second argument named variant. This was deprecated in favor
1647          * of passing an array of option with a "variant" key
1648          * Once $query2 is removed for good, this helper can be dropped
1649          * and the wfArrayToCgi moved to getLocalURL();
1650          *
1651          * @since 1.19 (r105919)
1652          * @param array|string $query
1653          * @param bool $query2
1654          * @return string
1655          */
1656         private static function fixUrlQueryArgs( $query, $query2 = false ) {
1657                 if ( $query2 !== false ) {
1658                         wfDeprecated( "Title::get{Canonical,Full,Link,Local,Internal}URL " .
1659                                 "method called with a second parameter is deprecated. Add your " .
1660                                 "parameter to an array passed as the first parameter.", "1.19" );
1661                 }
1662                 if ( is_array( $query ) ) {
1663                         $query = wfArrayToCgi( $query );
1664                 }
1665                 if ( $query2 ) {
1666                         if ( is_string( $query2 ) ) {
1667                                 // $query2 is a string, we will consider this to be
1668                                 // a deprecated $variant argument and add it to the query
1669                                 $query2 = wfArrayToCgi( [ 'variant' => $query2 ] );
1670                         } else {
1671                                 $query2 = wfArrayToCgi( $query2 );
1672                         }
1673                         // If we have $query content add a & to it first
1674                         if ( $query ) {
1675                                 $query .= '&';
1676                         }
1677                         // Now append the queries together
1678                         $query .= $query2;
1679                 }
1680                 return $query;
1681         }
1682
1683         /**
1684          * Get a real URL referring to this title, with interwiki link and
1685          * fragment
1686          *
1687          * @see self::getLocalURL for the arguments.
1688          * @see wfExpandUrl
1689          * @param array|string $query
1690          * @param bool $query2
1691          * @param string $proto Protocol type to use in URL
1692          * @return string The URL
1693          */
1694         public function getFullURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1695                 $query = self::fixUrlQueryArgs( $query, $query2 );
1696
1697                 # Hand off all the decisions on urls to getLocalURL
1698                 $url = $this->getLocalURL( $query );
1699
1700                 # Expand the url to make it a full url. Note that getLocalURL has the
1701                 # potential to output full urls for a variety of reasons, so we use
1702                 # wfExpandUrl instead of simply prepending $wgServer
1703                 $url = wfExpandUrl( $url, $proto );
1704
1705                 # Finally, add the fragment.
1706                 $url .= $this->getFragmentForURL();
1707
1708                 Hooks::run( 'GetFullURL', [ &$this, &$url, $query ] );
1709                 return $url;
1710         }
1711
1712         /**
1713          * Get a URL with no fragment or server name (relative URL) from a Title object.
1714          * If this page is generated with action=render, however,
1715          * $wgServer is prepended to make an absolute URL.
1716          *
1717          * @see self::getFullURL to always get an absolute URL.
1718          * @see self::getLinkURL to always get a URL that's the simplest URL that will be
1719          *  valid to link, locally, to the current Title.
1720          * @see self::newFromText to produce a Title object.
1721          *
1722          * @param string|array $query An optional query string,
1723          *   not used for interwiki links. Can be specified as an associative array as well,
1724          *   e.g., array( 'action' => 'edit' ) (keys and values will be URL-escaped).
1725          *   Some query patterns will trigger various shorturl path replacements.
1726          * @param array $query2 An optional secondary query array. This one MUST
1727          *   be an array. If a string is passed it will be interpreted as a deprecated
1728          *   variant argument and urlencoded into a variant= argument.
1729          *   This second query argument will be added to the $query
1730          *   The second parameter is deprecated since 1.19. Pass it as a key,value
1731          *   pair in the first parameter array instead.
1732          *
1733          * @return string String of the URL.
1734          */
1735         public function getLocalURL( $query = '', $query2 = false ) {
1736                 global $wgArticlePath, $wgScript, $wgServer, $wgRequest;
1737
1738                 $query = self::fixUrlQueryArgs( $query, $query2 );
1739
1740                 $interwiki = Interwiki::fetch( $this->mInterwiki );
1741                 if ( $interwiki ) {
1742                         $namespace = $this->getNsText();
1743                         if ( $namespace != '' ) {
1744                                 # Can this actually happen? Interwikis shouldn't be parsed.
1745                                 # Yes! It can in interwiki transclusion. But... it probably shouldn't.
1746                                 $namespace .= ':';
1747                         }
1748                         $url = $interwiki->getURL( $namespace . $this->getDBkey() );
1749                         $url = wfAppendQuery( $url, $query );
1750                 } else {
1751                         $dbkey = wfUrlencode( $this->getPrefixedDBkey() );
1752                         if ( $query == '' ) {
1753                                 $url = str_replace( '$1', $dbkey, $wgArticlePath );
1754                                 Hooks::run( 'GetLocalURL::Article', [ &$this, &$url ] );
1755                         } else {
1756                                 global $wgVariantArticlePath, $wgActionPaths, $wgContLang;
1757                                 $url = false;
1758                                 $matches = [];
1759
1760                                 if ( !empty( $wgActionPaths )
1761                                         && preg_match( '/^(.*&|)action=([^&]*)(&(.*)|)$/', $query, $matches )
1762                                 ) {
1763                                         $action = urldecode( $matches[2] );
1764                                         if ( isset( $wgActionPaths[$action] ) ) {
1765                                                 $query = $matches[1];
1766                                                 if ( isset( $matches[4] ) ) {
1767                                                         $query .= $matches[4];
1768                                                 }
1769                                                 $url = str_replace( '$1', $dbkey, $wgActionPaths[$action] );
1770                                                 if ( $query != '' ) {
1771                                                         $url = wfAppendQuery( $url, $query );
1772                                                 }
1773                                         }
1774                                 }
1775
1776                                 if ( $url === false
1777                                         && $wgVariantArticlePath
1778                                         && $wgContLang->getCode() === $this->getPageLanguage()->getCode()
1779                                         && $this->getPageLanguage()->hasVariants()
1780                                         && preg_match( '/^variant=([^&]*)$/', $query, $matches )
1781                                 ) {
1782                                         $variant = urldecode( $matches[1] );
1783                                         if ( $this->getPageLanguage()->hasVariant( $variant ) ) {
1784                                                 // Only do the variant replacement if the given variant is a valid
1785                                                 // variant for the page's language.
1786                                                 $url = str_replace( '$2', urlencode( $variant ), $wgVariantArticlePath );
1787                                                 $url = str_replace( '$1', $dbkey, $url );
1788                                         }
1789                                 }
1790
1791                                 if ( $url === false ) {
1792                                         if ( $query == '-' ) {
1793                                                 $query = '';
1794                                         }
1795                                         $url = "{$wgScript}?title={$dbkey}&{$query}";
1796                                 }
1797                         }
1798
1799                         Hooks::run( 'GetLocalURL::Internal', [ &$this, &$url, $query ] );
1800
1801                         // @todo FIXME: This causes breakage in various places when we
1802                         // actually expected a local URL and end up with dupe prefixes.
1803                         if ( $wgRequest->getVal( 'action' ) == 'render' ) {
1804                                 $url = $wgServer . $url;
1805                         }
1806                 }
1807                 Hooks::run( 'GetLocalURL', [ &$this, &$url, $query ] );
1808                 return $url;
1809         }
1810
1811         /**
1812          * Get a URL that's the simplest URL that will be valid to link, locally,
1813          * to the current Title.  It includes the fragment, but does not include
1814          * the server unless action=render is used (or the link is external).  If
1815          * there's a fragment but the prefixed text is empty, we just return a link
1816          * to the fragment.
1817          *
1818          * The result obviously should not be URL-escaped, but does need to be
1819          * HTML-escaped if it's being output in HTML.
1820          *
1821          * @param array $query
1822          * @param bool $query2
1823          * @param string $proto Protocol to use; setting this will cause a full URL to be used
1824          * @see self::getLocalURL for the arguments.
1825          * @return string The URL
1826          */
1827         public function getLinkURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1828                 if ( $this->isExternal() || $proto !== PROTO_RELATIVE ) {
1829                         $ret = $this->getFullURL( $query, $query2, $proto );
1830                 } elseif ( $this->getPrefixedText() === '' && $this->hasFragment() ) {
1831                         $ret = $this->getFragmentForURL();
1832                 } else {
1833                         $ret = $this->getLocalURL( $query, $query2 ) . $this->getFragmentForURL();
1834                 }
1835                 return $ret;
1836         }
1837
1838         /**
1839          * Get the URL form for an internal link.
1840          * - Used in various CDN-related code, in case we have a different
1841          * internal hostname for the server from the exposed one.
1842          *
1843          * This uses $wgInternalServer to qualify the path, or $wgServer
1844          * if $wgInternalServer is not set. If the server variable used is
1845          * protocol-relative, the URL will be expanded to http://
1846          *
1847          * @see self::getLocalURL for the arguments.
1848          * @return string The URL
1849          */
1850         public function getInternalURL( $query = '', $query2 = false ) {
1851                 global $wgInternalServer, $wgServer;
1852                 $query = self::fixUrlQueryArgs( $query, $query2 );
1853                 $server = $wgInternalServer !== false ? $wgInternalServer : $wgServer;
1854                 $url = wfExpandUrl( $server . $this->getLocalURL( $query ), PROTO_HTTP );
1855                 Hooks::run( 'GetInternalURL', [ &$this, &$url, $query ] );
1856                 return $url;
1857         }
1858
1859         /**
1860          * Get the URL for a canonical link, for use in things like IRC and
1861          * e-mail notifications. Uses $wgCanonicalServer and the
1862          * GetCanonicalURL hook.
1863          *
1864          * NOTE: Unlike getInternalURL(), the canonical URL includes the fragment
1865          *
1866          * @see self::getLocalURL for the arguments.
1867          * @return string The URL
1868          * @since 1.18
1869          */
1870         public function getCanonicalURL( $query = '', $query2 = false ) {
1871                 $query = self::fixUrlQueryArgs( $query, $query2 );
1872                 $url = wfExpandUrl( $this->getLocalURL( $query ) . $this->getFragmentForURL(), PROTO_CANONICAL );
1873                 Hooks::run( 'GetCanonicalURL', [ &$this, &$url, $query ] );
1874                 return $url;
1875         }
1876
1877         /**
1878          * Get the edit URL for this Title
1879          *
1880          * @return string The URL, or a null string if this is an interwiki link
1881          */
1882         public function getEditURL() {
1883                 if ( $this->isExternal() ) {
1884                         return '';
1885                 }
1886                 $s = $this->getLocalURL( 'action=edit' );
1887
1888                 return $s;
1889         }
1890
1891         /**
1892          * Can $user perform $action on this page?
1893          * This skips potentially expensive cascading permission checks
1894          * as well as avoids expensive error formatting
1895          *
1896          * Suitable for use for nonessential UI controls in common cases, but
1897          * _not_ for functional access control.
1898          *
1899          * May provide false positives, but should never provide a false negative.
1900          *
1901          * @param string $action Action that permission needs to be checked for
1902          * @param User $user User to check (since 1.19); $wgUser will be used if not provided.
1903          * @return bool
1904          */
1905         public function quickUserCan( $action, $user = null ) {
1906                 return $this->userCan( $action, $user, false );
1907         }
1908
1909         /**
1910          * Can $user perform $action on this page?
1911          *
1912          * @param string $action Action that permission needs to be checked for
1913          * @param User $user User to check (since 1.19); $wgUser will be used if not
1914          *   provided.
1915          * @param string $rigor Same format as Title::getUserPermissionsErrors()
1916          * @return bool
1917          */
1918         public function userCan( $action, $user = null, $rigor = 'secure' ) {
1919                 if ( !$user instanceof User ) {
1920                         global $wgUser;
1921                         $user = $wgUser;
1922                 }
1923
1924                 return !count( $this->getUserPermissionsErrorsInternal( $action, $user, $rigor, true ) );
1925         }
1926
1927         /**
1928          * Can $user perform $action on this page?
1929          *
1930          * @todo FIXME: This *does not* check throttles (User::pingLimiter()).
1931          *
1932          * @param string $action Action that permission needs to be checked for
1933          * @param User $user User to check
1934          * @param string $rigor One of (quick,full,secure)
1935          *   - quick  : does cheap permission checks from slaves (usable for GUI creation)
1936          *   - full   : does cheap and expensive checks possibly from a slave
1937          *   - secure : does cheap and expensive checks, using the master as needed
1938          * @param array $ignoreErrors Array of Strings Set this to a list of message keys
1939          *   whose corresponding errors may be ignored.
1940          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
1941          */
1942         public function getUserPermissionsErrors(
1943                 $action, $user, $rigor = 'secure', $ignoreErrors = []
1944         ) {
1945                 $errors = $this->getUserPermissionsErrorsInternal( $action, $user, $rigor );
1946
1947                 // Remove the errors being ignored.
1948                 foreach ( $errors as $index => $error ) {
1949                         $errKey = is_array( $error ) ? $error[0] : $error;
1950
1951                         if ( in_array( $errKey, $ignoreErrors ) ) {
1952                                 unset( $errors[$index] );
1953                         }
1954                         if ( $errKey instanceof MessageSpecifier && in_array( $errKey->getKey(), $ignoreErrors ) ) {
1955                                 unset( $errors[$index] );
1956                         }
1957                 }
1958
1959                 return $errors;
1960         }
1961
1962         /**
1963          * Permissions checks that fail most often, and which are easiest to test.
1964          *
1965          * @param string $action The action to check
1966          * @param User $user User to check
1967          * @param array $errors List of current errors
1968          * @param string $rigor Same format as Title::getUserPermissionsErrors()
1969          * @param bool $short Short circuit on first error
1970          *
1971          * @return array List of errors
1972          */
1973         private function checkQuickPermissions( $action, $user, $errors, $rigor, $short ) {
1974                 if ( !Hooks::run( 'TitleQuickPermissions',
1975                         [ $this, $user, $action, &$errors, ( $rigor !== 'quick' ), $short ] )
1976                 ) {
1977                         return $errors;
1978                 }
1979
1980                 if ( $action == 'create' ) {
1981                         if (
1982                                 ( $this->isTalkPage() && !$user->isAllowed( 'createtalk' ) ) ||
1983                                 ( !$this->isTalkPage() && !$user->isAllowed( 'createpage' ) )
1984                         ) {
1985                                 $errors[] = $user->isAnon() ? [ 'nocreatetext' ] : [ 'nocreate-loggedin' ];
1986                         }
1987                 } elseif ( $action == 'move' ) {
1988                         if ( !$user->isAllowed( 'move-rootuserpages' )
1989                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
1990                                 // Show user page-specific message only if the user can move other pages
1991                                 $errors[] = [ 'cant-move-user-page' ];
1992                         }
1993
1994                         // Check if user is allowed to move files if it's a file
1995                         if ( $this->mNamespace == NS_FILE && !$user->isAllowed( 'movefile' ) ) {
1996                                 $errors[] = [ 'movenotallowedfile' ];
1997                         }
1998
1999                         // Check if user is allowed to move category pages if it's a category page
2000                         if ( $this->mNamespace == NS_CATEGORY && !$user->isAllowed( 'move-categorypages' ) ) {
2001                                 $errors[] = [ 'cant-move-category-page' ];
2002                         }
2003
2004                         if ( !$user->isAllowed( 'move' ) ) {
2005                                 // User can't move anything
2006                                 $userCanMove = User::groupHasPermission( 'user', 'move' );
2007                                 $autoconfirmedCanMove = User::groupHasPermission( 'autoconfirmed', 'move' );
2008                                 if ( $user->isAnon() && ( $userCanMove || $autoconfirmedCanMove ) ) {
2009                                         // custom message if logged-in users without any special rights can move
2010                                         $errors[] = [ 'movenologintext' ];
2011                                 } else {
2012                                         $errors[] = [ 'movenotallowed' ];
2013                                 }
2014                         }
2015                 } elseif ( $action == 'move-target' ) {
2016                         if ( !$user->isAllowed( 'move' ) ) {
2017                                 // User can't move anything
2018                                 $errors[] = [ 'movenotallowed' ];
2019                         } elseif ( !$user->isAllowed( 'move-rootuserpages' )
2020                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
2021                                 // Show user page-specific message only if the user can move other pages
2022                                 $errors[] = [ 'cant-move-to-user-page' ];
2023                         } elseif ( !$user->isAllowed( 'move-categorypages' )
2024                                         && $this->mNamespace == NS_CATEGORY ) {
2025                                 // Show category page-specific message only if the user can move other pages
2026                                 $errors[] = [ 'cant-move-to-category-page' ];
2027                         }
2028                 } elseif ( !$user->isAllowed( $action ) ) {
2029                         $errors[] = $this->missingPermissionError( $action, $short );
2030                 }
2031
2032                 return $errors;
2033         }
2034
2035         /**
2036          * Add the resulting error code to the errors array
2037          *
2038          * @param array $errors List of current errors
2039          * @param array $result Result of errors
2040          *
2041          * @return array List of errors
2042          */
2043         private function resultToError( $errors, $result ) {
2044                 if ( is_array( $result ) && count( $result ) && !is_array( $result[0] ) ) {
2045                         // A single array representing an error
2046                         $errors[] = $result;
2047                 } elseif ( is_array( $result ) && is_array( $result[0] ) ) {
2048                         // A nested array representing multiple errors
2049                         $errors = array_merge( $errors, $result );
2050                 } elseif ( $result !== '' && is_string( $result ) ) {
2051                         // A string representing a message-id
2052                         $errors[] = [ $result ];
2053                 } elseif ( $result instanceof MessageSpecifier ) {
2054                         // A message specifier representing an error
2055                         $errors[] = [ $result ];
2056                 } elseif ( $result === false ) {
2057                         // a generic "We don't want them to do that"
2058                         $errors[] = [ 'badaccess-group0' ];
2059                 }
2060                 return $errors;
2061         }
2062
2063         /**
2064          * Check various permission hooks
2065          *
2066          * @param string $action The action to check
2067          * @param User $user User to check
2068          * @param array $errors List of current errors
2069          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2070          * @param bool $short Short circuit on first error
2071          *
2072          * @return array List of errors
2073          */
2074         private function checkPermissionHooks( $action, $user, $errors, $rigor, $short ) {
2075                 // Use getUserPermissionsErrors instead
2076                 $result = '';
2077                 if ( !Hooks::run( 'userCan', [ &$this, &$user, $action, &$result ] ) ) {
2078                         return $result ? [] : [ [ 'badaccess-group0' ] ];
2079                 }
2080                 // Check getUserPermissionsErrors hook
2081                 if ( !Hooks::run( 'getUserPermissionsErrors', [ &$this, &$user, $action, &$result ] ) ) {
2082                         $errors = $this->resultToError( $errors, $result );
2083                 }
2084                 // Check getUserPermissionsErrorsExpensive hook
2085                 if (
2086                         $rigor !== 'quick'
2087                         && !( $short && count( $errors ) > 0 )
2088                         && !Hooks::run( 'getUserPermissionsErrorsExpensive', [ &$this, &$user, $action, &$result ] )
2089                 ) {
2090                         $errors = $this->resultToError( $errors, $result );
2091                 }
2092
2093                 return $errors;
2094         }
2095
2096         /**
2097          * Check permissions on special pages & namespaces
2098          *
2099          * @param string $action The action to check
2100          * @param User $user User to check
2101          * @param array $errors List of current errors
2102          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2103          * @param bool $short Short circuit on first error
2104          *
2105          * @return array List of errors
2106          */
2107         private function checkSpecialsAndNSPermissions( $action, $user, $errors, $rigor, $short ) {
2108                 # Only 'createaccount' can be performed on special pages,
2109                 # which don't actually exist in the DB.
2110                 if ( NS_SPECIAL == $this->mNamespace && $action !== 'createaccount' ) {
2111                         $errors[] = [ 'ns-specialprotected' ];
2112                 }
2113
2114                 # Check $wgNamespaceProtection for restricted namespaces
2115                 if ( $this->isNamespaceProtected( $user ) ) {
2116                         $ns = $this->mNamespace == NS_MAIN ?
2117                                 wfMessage( 'nstab-main' )->text() : $this->getNsText();
2118                         $errors[] = $this->mNamespace == NS_MEDIAWIKI ?
2119                                 [ 'protectedinterface', $action ] : [ 'namespaceprotected', $ns, $action ];
2120                 }
2121
2122                 return $errors;
2123         }
2124
2125         /**
2126          * Check CSS/JS sub-page permissions
2127          *
2128          * @param string $action The action to check
2129          * @param User $user User to check
2130          * @param array $errors List of current errors
2131          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2132          * @param bool $short Short circuit on first error
2133          *
2134          * @return array List of errors
2135          */
2136         private function checkCSSandJSPermissions( $action, $user, $errors, $rigor, $short ) {
2137                 # Protect css/js subpages of user pages
2138                 # XXX: this might be better using restrictions
2139                 # XXX: right 'editusercssjs' is deprecated, for backward compatibility only
2140                 if ( $action != 'patrol' && !$user->isAllowed( 'editusercssjs' ) ) {
2141                         if ( preg_match( '/^' . preg_quote( $user->getName(), '/' ) . '\//', $this->mTextform ) ) {
2142                                 if ( $this->isCssSubpage() && !$user->isAllowedAny( 'editmyusercss', 'editusercss' ) ) {
2143                                         $errors[] = [ 'mycustomcssprotected', $action ];
2144                                 } elseif ( $this->isJsSubpage() && !$user->isAllowedAny( 'editmyuserjs', 'edituserjs' ) ) {
2145                                         $errors[] = [ 'mycustomjsprotected', $action ];
2146                                 }
2147                         } else {
2148                                 if ( $this->isCssSubpage() && !$user->isAllowed( 'editusercss' ) ) {
2149                                         $errors[] = [ 'customcssprotected', $action ];
2150                                 } elseif ( $this->isJsSubpage() && !$user->isAllowed( 'edituserjs' ) ) {
2151                                         $errors[] = [ 'customjsprotected', $action ];
2152                                 }
2153                         }
2154                 }
2155
2156                 return $errors;
2157         }
2158
2159         /**
2160          * Check against page_restrictions table requirements on this
2161          * page. The user must possess all required rights for this
2162          * action.
2163          *
2164          * @param string $action The action to check
2165          * @param User $user User to check
2166          * @param array $errors List of current errors
2167          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2168          * @param bool $short Short circuit on first error
2169          *
2170          * @return array List of errors
2171          */
2172         private function checkPageRestrictions( $action, $user, $errors, $rigor, $short ) {
2173                 foreach ( $this->getRestrictions( $action ) as $right ) {
2174                         // Backwards compatibility, rewrite sysop -> editprotected
2175                         if ( $right == 'sysop' ) {
2176                                 $right = 'editprotected';
2177                         }
2178                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2179                         if ( $right == 'autoconfirmed' ) {
2180                                 $right = 'editsemiprotected';
2181                         }
2182                         if ( $right == '' ) {
2183                                 continue;
2184                         }
2185                         if ( !$user->isAllowed( $right ) ) {
2186                                 $errors[] = [ 'protectedpagetext', $right, $action ];
2187                         } elseif ( $this->mCascadeRestriction && !$user->isAllowed( 'protect' ) ) {
2188                                 $errors[] = [ 'protectedpagetext', 'protect', $action ];
2189                         }
2190                 }
2191
2192                 return $errors;
2193         }
2194
2195         /**
2196          * Check restrictions on cascading pages.
2197          *
2198          * @param string $action The action to check
2199          * @param User $user User to check
2200          * @param array $errors List of current errors
2201          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2202          * @param bool $short Short circuit on first error
2203          *
2204          * @return array List of errors
2205          */
2206         private function checkCascadingSourcesRestrictions( $action, $user, $errors, $rigor, $short ) {
2207                 if ( $rigor !== 'quick' && !$this->isCssJsSubpage() ) {
2208                         # We /could/ use the protection level on the source page, but it's
2209                         # fairly ugly as we have to establish a precedence hierarchy for pages
2210                         # included by multiple cascade-protected pages. So just restrict
2211                         # it to people with 'protect' permission, as they could remove the
2212                         # protection anyway.
2213                         list( $cascadingSources, $restrictions ) = $this->getCascadeProtectionSources();
2214                         # Cascading protection depends on more than this page...
2215                         # Several cascading protected pages may include this page...
2216                         # Check each cascading level
2217                         # This is only for protection restrictions, not for all actions
2218                         if ( isset( $restrictions[$action] ) ) {
2219                                 foreach ( $restrictions[$action] as $right ) {
2220                                         // Backwards compatibility, rewrite sysop -> editprotected
2221                                         if ( $right == 'sysop' ) {
2222                                                 $right = 'editprotected';
2223                                         }
2224                                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2225                                         if ( $right == 'autoconfirmed' ) {
2226                                                 $right = 'editsemiprotected';
2227                                         }
2228                                         if ( $right != '' && !$user->isAllowedAll( 'protect', $right ) ) {
2229                                                 $pages = '';
2230                                                 foreach ( $cascadingSources as $page ) {
2231                                                         $pages .= '* [[:' . $page->getPrefixedText() . "]]\n";
2232                                                 }
2233                                                 $errors[] = [ 'cascadeprotected', count( $cascadingSources ), $pages, $action ];
2234                                         }
2235                                 }
2236                         }
2237                 }
2238
2239                 return $errors;
2240         }
2241
2242         /**
2243          * Check action permissions not already checked in checkQuickPermissions
2244          *
2245          * @param string $action The action to check
2246          * @param User $user User to check
2247          * @param array $errors List of current errors
2248          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2249          * @param bool $short Short circuit on first error
2250          *
2251          * @return array List of errors
2252          */
2253         private function checkActionPermissions( $action, $user, $errors, $rigor, $short ) {
2254                 global $wgDeleteRevisionsLimit, $wgLang;
2255
2256                 if ( $action == 'protect' ) {
2257                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit', $user, $rigor, true ) ) ) {
2258                                 // If they can't edit, they shouldn't protect.
2259                                 $errors[] = [ 'protect-cantedit' ];
2260                         }
2261                 } elseif ( $action == 'create' ) {
2262                         $title_protection = $this->getTitleProtection();
2263                         if ( $title_protection ) {
2264                                 if ( $title_protection['permission'] == ''
2265                                         || !$user->isAllowed( $title_protection['permission'] )
2266                                 ) {
2267                                         $errors[] = [
2268                                                 'titleprotected',
2269                                                 User::whoIs( $title_protection['user'] ),
2270                                                 $title_protection['reason']
2271                                         ];
2272                                 }
2273                         }
2274                 } elseif ( $action == 'move' ) {
2275                         // Check for immobile pages
2276                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2277                                 // Specific message for this case
2278                                 $errors[] = [ 'immobile-source-namespace', $this->getNsText() ];
2279                         } elseif ( !$this->isMovable() ) {
2280                                 // Less specific message for rarer cases
2281                                 $errors[] = [ 'immobile-source-page' ];
2282                         }
2283                 } elseif ( $action == 'move-target' ) {
2284                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2285                                 $errors[] = [ 'immobile-target-namespace', $this->getNsText() ];
2286                         } elseif ( !$this->isMovable() ) {
2287                                 $errors[] = [ 'immobile-target-page' ];
2288                         }
2289                 } elseif ( $action == 'delete' ) {
2290                         $tempErrors = $this->checkPageRestrictions( 'edit', $user, [], $rigor, true );
2291                         if ( !$tempErrors ) {
2292                                 $tempErrors = $this->checkCascadingSourcesRestrictions( 'edit',
2293                                         $user, $tempErrors, $rigor, true );
2294                         }
2295                         if ( $tempErrors ) {
2296                                 // If protection keeps them from editing, they shouldn't be able to delete.
2297                                 $errors[] = [ 'deleteprotected' ];
2298                         }
2299                         if ( $rigor !== 'quick' && $wgDeleteRevisionsLimit
2300                                 && !$this->userCan( 'bigdelete', $user ) && $this->isBigDeletion()
2301                         ) {
2302                                 $errors[] = [ 'delete-toobig', $wgLang->formatNum( $wgDeleteRevisionsLimit ) ];
2303                         }
2304                 }
2305                 return $errors;
2306         }
2307
2308         /**
2309          * Check that the user isn't blocked from editing.
2310          *
2311          * @param string $action The action to check
2312          * @param User $user User to check
2313          * @param array $errors List of current errors
2314          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2315          * @param bool $short Short circuit on first error
2316          *
2317          * @return array List of errors
2318          */
2319         private function checkUserBlock( $action, $user, $errors, $rigor, $short ) {
2320                 // Account creation blocks handled at userlogin.
2321                 // Unblocking handled in SpecialUnblock
2322                 if ( $rigor === 'quick' || in_array( $action, [ 'createaccount', 'unblock' ] ) ) {
2323                         return $errors;
2324                 }
2325
2326                 global $wgEmailConfirmToEdit;
2327
2328                 if ( $wgEmailConfirmToEdit && !$user->isEmailConfirmed() ) {
2329                         $errors[] = [ 'confirmedittext' ];
2330                 }
2331
2332                 $useSlave = ( $rigor !== 'secure' );
2333                 if ( ( $action == 'edit' || $action == 'create' )
2334                         && !$user->isBlockedFrom( $this, $useSlave )
2335                 ) {
2336                         // Don't block the user from editing their own talk page unless they've been
2337                         // explicitly blocked from that too.
2338                 } elseif ( $user->isBlocked() && $user->getBlock()->prevents( $action ) !== false ) {
2339                         // @todo FIXME: Pass the relevant context into this function.
2340                         $errors[] = $user->getBlock()->getPermissionsError( RequestContext::getMain() );
2341                 }
2342
2343                 return $errors;
2344         }
2345
2346         /**
2347          * Check that the user is allowed to read this page.
2348          *
2349          * @param string $action The action to check
2350          * @param User $user User to check
2351          * @param array $errors List of current errors
2352          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2353          * @param bool $short Short circuit on first error
2354          *
2355          * @return array List of errors
2356          */
2357         private function checkReadPermissions( $action, $user, $errors, $rigor, $short ) {
2358                 global $wgWhitelistRead, $wgWhitelistReadRegexp;
2359
2360                 $whitelisted = false;
2361                 if ( User::isEveryoneAllowed( 'read' ) ) {
2362                         # Shortcut for public wikis, allows skipping quite a bit of code
2363                         $whitelisted = true;
2364                 } elseif ( $user->isAllowed( 'read' ) ) {
2365                         # If the user is allowed to read pages, he is allowed to read all pages
2366                         $whitelisted = true;
2367                 } elseif ( $this->isSpecial( 'Userlogin' )
2368                         || $this->isSpecial( 'ChangePassword' )
2369                         || $this->isSpecial( 'PasswordReset' )
2370                 ) {
2371                         # Always grant access to the login page.
2372                         # Even anons need to be able to log in.
2373                         $whitelisted = true;
2374                 } elseif ( is_array( $wgWhitelistRead ) && count( $wgWhitelistRead ) ) {
2375                         # Time to check the whitelist
2376                         # Only do these checks is there's something to check against
2377                         $name = $this->getPrefixedText();
2378                         $dbName = $this->getPrefixedDBkey();
2379
2380                         // Check for explicit whitelisting with and without underscores
2381                         if ( in_array( $name, $wgWhitelistRead, true ) || in_array( $dbName, $wgWhitelistRead, true ) ) {
2382                                 $whitelisted = true;
2383                         } elseif ( $this->getNamespace() == NS_MAIN ) {
2384                                 # Old settings might have the title prefixed with
2385                                 # a colon for main-namespace pages
2386                                 if ( in_array( ':' . $name, $wgWhitelistRead ) ) {
2387                                         $whitelisted = true;
2388                                 }
2389                         } elseif ( $this->isSpecialPage() ) {
2390                                 # If it's a special page, ditch the subpage bit and check again
2391                                 $name = $this->getDBkey();
2392                                 list( $name, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $name );
2393                                 if ( $name ) {
2394                                         $pure = SpecialPage::getTitleFor( $name )->getPrefixedText();
2395                                         if ( in_array( $pure, $wgWhitelistRead, true ) ) {
2396                                                 $whitelisted = true;
2397                                         }
2398                                 }
2399                         }
2400                 }
2401
2402                 if ( !$whitelisted && is_array( $wgWhitelistReadRegexp ) && !empty( $wgWhitelistReadRegexp ) ) {
2403                         $name = $this->getPrefixedText();
2404                         // Check for regex whitelisting
2405                         foreach ( $wgWhitelistReadRegexp as $listItem ) {
2406                                 if ( preg_match( $listItem, $name ) ) {
2407                                         $whitelisted = true;
2408                                         break;
2409                                 }
2410                         }
2411                 }
2412
2413                 if ( !$whitelisted ) {
2414                         # If the title is not whitelisted, give extensions a chance to do so...
2415                         Hooks::run( 'TitleReadWhitelist', [ $this, $user, &$whitelisted ] );
2416                         if ( !$whitelisted ) {
2417                                 $errors[] = $this->missingPermissionError( $action, $short );
2418                         }
2419                 }
2420
2421                 return $errors;
2422         }
2423
2424         /**
2425          * Get a description array when the user doesn't have the right to perform
2426          * $action (i.e. when User::isAllowed() returns false)
2427          *
2428          * @param string $action The action to check
2429          * @param bool $short Short circuit on first error
2430          * @return array List of errors
2431          */
2432         private function missingPermissionError( $action, $short ) {
2433                 // We avoid expensive display logic for quickUserCan's and such
2434                 if ( $short ) {
2435                         return [ 'badaccess-group0' ];
2436                 }
2437
2438                 $groups = array_map( [ 'User', 'makeGroupLinkWiki' ],
2439                         User::getGroupsWithPermission( $action ) );
2440
2441                 if ( count( $groups ) ) {
2442                         global $wgLang;
2443                         return [
2444                                 'badaccess-groups',
2445                                 $wgLang->commaList( $groups ),
2446                                 count( $groups )
2447                         ];
2448                 } else {
2449                         return [ 'badaccess-group0' ];
2450                 }
2451         }
2452
2453         /**
2454          * Can $user perform $action on this page? This is an internal function,
2455          * with multiple levels of checks depending on performance needs; see $rigor below.
2456          * It does not check wfReadOnly().
2457          *
2458          * @param string $action Action that permission needs to be checked for
2459          * @param User $user User to check
2460          * @param string $rigor One of (quick,full,secure)
2461          *   - quick  : does cheap permission checks from slaves (usable for GUI creation)
2462          *   - full   : does cheap and expensive checks possibly from a slave
2463          *   - secure : does cheap and expensive checks, using the master as needed
2464          * @param bool $short Set this to true to stop after the first permission error.
2465          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
2466          */
2467         protected function getUserPermissionsErrorsInternal(
2468                 $action, $user, $rigor = 'secure', $short = false
2469         ) {
2470                 if ( $rigor === true ) {
2471                         $rigor = 'secure'; // b/c
2472                 } elseif ( $rigor === false ) {
2473                         $rigor = 'quick'; // b/c
2474                 } elseif ( !in_array( $rigor, [ 'quick', 'full', 'secure' ] ) ) {
2475                         throw new Exception( "Invalid rigor parameter '$rigor'." );
2476                 }
2477
2478                 # Read has special handling
2479                 if ( $action == 'read' ) {
2480                         $checks = [
2481                                 'checkPermissionHooks',
2482                                 'checkReadPermissions',
2483                         ];
2484                 # Don't call checkSpecialsAndNSPermissions or checkCSSandJSPermissions
2485                 # here as it will lead to duplicate error messages. This is okay to do
2486                 # since anywhere that checks for create will also check for edit, and
2487                 # those checks are called for edit.
2488                 } elseif ( $action == 'create' ) {
2489                         $checks = [
2490                                 'checkQuickPermissions',
2491                                 'checkPermissionHooks',
2492                                 'checkPageRestrictions',
2493                                 'checkCascadingSourcesRestrictions',
2494                                 'checkActionPermissions',
2495                                 'checkUserBlock'
2496                         ];
2497                 } else {
2498                         $checks = [
2499                                 'checkQuickPermissions',
2500                                 'checkPermissionHooks',
2501                                 'checkSpecialsAndNSPermissions',
2502                                 'checkCSSandJSPermissions',
2503                                 'checkPageRestrictions',
2504                                 'checkCascadingSourcesRestrictions',
2505                                 'checkActionPermissions',
2506                                 'checkUserBlock'
2507                         ];
2508                 }
2509
2510                 $errors = [];
2511                 while ( count( $checks ) > 0 &&
2512                                 !( $short && count( $errors ) > 0 ) ) {
2513                         $method = array_shift( $checks );
2514                         $errors = $this->$method( $action, $user, $errors, $rigor, $short );
2515                 }
2516
2517                 return $errors;
2518         }
2519
2520         /**
2521          * Get a filtered list of all restriction types supported by this wiki.
2522          * @param bool $exists True to get all restriction types that apply to
2523          * titles that do exist, False for all restriction types that apply to
2524          * titles that do not exist
2525          * @return array
2526          */
2527         public static function getFilteredRestrictionTypes( $exists = true ) {
2528                 global $wgRestrictionTypes;
2529                 $types = $wgRestrictionTypes;
2530                 if ( $exists ) {
2531                         # Remove the create restriction for existing titles
2532                         $types = array_diff( $types, [ 'create' ] );
2533                 } else {
2534                         # Only the create and upload restrictions apply to non-existing titles
2535                         $types = array_intersect( $types, [ 'create', 'upload' ] );
2536                 }
2537                 return $types;
2538         }
2539
2540         /**
2541          * Returns restriction types for the current Title
2542          *
2543          * @return array Applicable restriction types
2544          */
2545         public function getRestrictionTypes() {
2546                 if ( $this->isSpecialPage() ) {
2547                         return [];
2548                 }
2549
2550                 $types = self::getFilteredRestrictionTypes( $this->exists() );
2551
2552                 if ( $this->getNamespace() != NS_FILE ) {
2553                         # Remove the upload restriction for non-file titles
2554                         $types = array_diff( $types, [ 'upload' ] );
2555                 }
2556
2557                 Hooks::run( 'TitleGetRestrictionTypes', [ $this, &$types ] );
2558
2559                 wfDebug( __METHOD__ . ': applicable restrictions to [[' .
2560                         $this->getPrefixedText() . ']] are {' . implode( ',', $types ) . "}\n" );
2561
2562                 return $types;
2563         }
2564
2565         /**
2566          * Is this title subject to title protection?
2567          * Title protection is the one applied against creation of such title.
2568          *
2569          * @return array|bool An associative array representing any existent title
2570          *   protection, or false if there's none.
2571          */
2572         public function getTitleProtection() {
2573                 // Can't protect pages in special namespaces
2574                 if ( $this->getNamespace() < 0 ) {
2575                         return false;
2576                 }
2577
2578                 // Can't protect pages that exist.
2579                 if ( $this->exists() ) {
2580                         return false;
2581                 }
2582
2583                 if ( $this->mTitleProtection === null ) {
2584                         $dbr = wfGetDB( DB_SLAVE );
2585                         $res = $dbr->select(
2586                                 'protected_titles',
2587                                 [
2588                                         'user' => 'pt_user',
2589                                         'reason' => 'pt_reason',
2590                                         'expiry' => 'pt_expiry',
2591                                         'permission' => 'pt_create_perm'
2592                                 ],
2593                                 [ 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ],
2594                                 __METHOD__
2595                         );
2596
2597                         // fetchRow returns false if there are no rows.
2598                         $row = $dbr->fetchRow( $res );
2599                         if ( $row ) {
2600                                 if ( $row['permission'] == 'sysop' ) {
2601                                         $row['permission'] = 'editprotected'; // B/C
2602                                 }
2603                                 if ( $row['permission'] == 'autoconfirmed' ) {
2604                                         $row['permission'] = 'editsemiprotected'; // B/C
2605                                 }
2606                                 $row['expiry'] = $dbr->decodeExpiry( $row['expiry'] );
2607                         }
2608                         $this->mTitleProtection = $row;
2609                 }
2610                 return $this->mTitleProtection;
2611         }
2612
2613         /**
2614          * Remove any title protection due to page existing
2615          */
2616         public function deleteTitleProtection() {
2617                 $dbw = wfGetDB( DB_MASTER );
2618
2619                 $dbw->delete(
2620                         'protected_titles',
2621                         [ 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ],
2622                         __METHOD__
2623                 );
2624                 $this->mTitleProtection = false;
2625         }
2626
2627         /**
2628          * Is this page "semi-protected" - the *only* protection levels are listed
2629          * in $wgSemiprotectedRestrictionLevels?
2630          *
2631          * @param string $action Action to check (default: edit)
2632          * @return bool
2633          */
2634         public function isSemiProtected( $action = 'edit' ) {
2635                 global $wgSemiprotectedRestrictionLevels;
2636
2637                 $restrictions = $this->getRestrictions( $action );
2638                 $semi = $wgSemiprotectedRestrictionLevels;
2639                 if ( !$restrictions || !$semi ) {
2640                         // Not protected, or all protection is full protection
2641                         return false;
2642                 }
2643
2644                 // Remap autoconfirmed to editsemiprotected for BC
2645                 foreach ( array_keys( $semi, 'autoconfirmed' ) as $key ) {
2646                         $semi[$key] = 'editsemiprotected';
2647                 }
2648                 foreach ( array_keys( $restrictions, 'autoconfirmed' ) as $key ) {
2649                         $restrictions[$key] = 'editsemiprotected';
2650                 }
2651
2652                 return !array_diff( $restrictions, $semi );
2653         }
2654
2655         /**
2656          * Does the title correspond to a protected article?
2657          *
2658          * @param string $action The action the page is protected from,
2659          * by default checks all actions.
2660          * @return bool
2661          */
2662         public function isProtected( $action = '' ) {
2663                 global $wgRestrictionLevels;
2664
2665                 $restrictionTypes = $this->getRestrictionTypes();
2666
2667                 # Special pages have inherent protection
2668                 if ( $this->isSpecialPage() ) {
2669                         return true;
2670                 }
2671
2672                 # Check regular protection levels
2673                 foreach ( $restrictionTypes as $type ) {
2674                         if ( $action == $type || $action == '' ) {
2675                                 $r = $this->getRestrictions( $type );
2676                                 foreach ( $wgRestrictionLevels as $level ) {
2677                                         if ( in_array( $level, $r ) && $level != '' ) {
2678                                                 return true;
2679                                         }
2680                                 }
2681                         }
2682                 }
2683
2684                 return false;
2685         }
2686
2687         /**
2688          * Determines if $user is unable to edit this page because it has been protected
2689          * by $wgNamespaceProtection.
2690          *
2691          * @param User $user User object to check permissions
2692          * @return bool
2693          */
2694         public function isNamespaceProtected( User $user ) {
2695                 global $wgNamespaceProtection;
2696
2697                 if ( isset( $wgNamespaceProtection[$this->mNamespace] ) ) {
2698                         foreach ( (array)$wgNamespaceProtection[$this->mNamespace] as $right ) {
2699                                 if ( $right != '' && !$user->isAllowed( $right ) ) {
2700                                         return true;
2701                                 }
2702                         }
2703                 }
2704                 return false;
2705         }
2706
2707         /**
2708          * Cascading protection: Return true if cascading restrictions apply to this page, false if not.
2709          *
2710          * @return bool If the page is subject to cascading restrictions.
2711          */
2712         public function isCascadeProtected() {
2713                 list( $sources, /* $restrictions */ ) = $this->getCascadeProtectionSources( false );
2714                 return ( $sources > 0 );
2715         }
2716
2717         /**
2718          * Determines whether cascading protection sources have already been loaded from
2719          * the database.
2720          *
2721          * @param bool $getPages True to check if the pages are loaded, or false to check
2722          * if the status is loaded.
2723          * @return bool Whether or not the specified information has been loaded
2724          * @since 1.23
2725          */
2726         public function areCascadeProtectionSourcesLoaded( $getPages = true ) {
2727                 return $getPages ? $this->mCascadeSources !== null : $this->mHasCascadingRestrictions !== null;
2728         }
2729
2730         /**
2731          * Cascading protection: Get the source of any cascading restrictions on this page.
2732          *
2733          * @param bool $getPages Whether or not to retrieve the actual pages
2734          *        that the restrictions have come from and the actual restrictions
2735          *        themselves.
2736          * @return array Two elements: First is an array of Title objects of the
2737          *        pages from which cascading restrictions have come, false for
2738          *        none, or true if such restrictions exist but $getPages was not
2739          *        set. Second is an array like that returned by
2740          *        Title::getAllRestrictions(), or an empty array if $getPages is
2741          *        false.
2742          */
2743         public function getCascadeProtectionSources( $getPages = true ) {
2744                 $pagerestrictions = [];
2745
2746                 if ( $this->mCascadeSources !== null && $getPages ) {
2747                         return [ $this->mCascadeSources, $this->mCascadingRestrictions ];
2748                 } elseif ( $this->mHasCascadingRestrictions !== null && !$getPages ) {
2749                         return [ $this->mHasCascadingRestrictions, $pagerestrictions ];
2750                 }
2751
2752                 $dbr = wfGetDB( DB_SLAVE );
2753
2754                 if ( $this->getNamespace() == NS_FILE ) {
2755                         $tables = [ 'imagelinks', 'page_restrictions' ];
2756                         $where_clauses = [
2757                                 'il_to' => $this->getDBkey(),
2758                                 'il_from=pr_page',
2759                                 'pr_cascade' => 1
2760                         ];
2761                 } else {
2762                         $tables = [ 'templatelinks', 'page_restrictions' ];
2763                         $where_clauses = [
2764                                 'tl_namespace' => $this->getNamespace(),
2765                                 'tl_title' => $this->getDBkey(),
2766                                 'tl_from=pr_page',
2767                                 'pr_cascade' => 1
2768                         ];
2769                 }
2770
2771                 if ( $getPages ) {
2772                         $cols = [ 'pr_page', 'page_namespace', 'page_title',
2773                                 'pr_expiry', 'pr_type', 'pr_level' ];
2774                         $where_clauses[] = 'page_id=pr_page';
2775                         $tables[] = 'page';
2776                 } else {
2777                         $cols = [ 'pr_expiry' ];
2778                 }
2779
2780                 $res = $dbr->select( $tables, $cols, $where_clauses, __METHOD__ );
2781
2782                 $sources = $getPages ? [] : false;
2783                 $now = wfTimestampNow();
2784
2785                 foreach ( $res as $row ) {
2786                         $expiry = $dbr->decodeExpiry( $row->pr_expiry );
2787                         if ( $expiry > $now ) {
2788                                 if ( $getPages ) {
2789                                         $page_id = $row->pr_page;
2790                                         $page_ns = $row->page_namespace;
2791                                         $page_title = $row->page_title;
2792                                         $sources[$page_id] = Title::makeTitle( $page_ns, $page_title );
2793                                         # Add groups needed for each restriction type if its not already there
2794                                         # Make sure this restriction type still exists
2795
2796                                         if ( !isset( $pagerestrictions[$row->pr_type] ) ) {
2797                                                 $pagerestrictions[$row->pr_type] = [];
2798                                         }
2799
2800                                         if (
2801                                                 isset( $pagerestrictions[$row->pr_type] )
2802                                                 && !in_array( $row->pr_level, $pagerestrictions[$row->pr_type] )
2803                                         ) {
2804                                                 $pagerestrictions[$row->pr_type][] = $row->pr_level;
2805                                         }
2806                                 } else {
2807                                         $sources = true;
2808                                 }
2809                         }
2810                 }
2811
2812                 if ( $getPages ) {
2813                         $this->mCascadeSources = $sources;
2814                         $this->mCascadingRestrictions = $pagerestrictions;
2815                 } else {
2816                         $this->mHasCascadingRestrictions = $sources;
2817                 }
2818
2819                 return [ $sources, $pagerestrictions ];
2820         }
2821
2822         /**
2823          * Accessor for mRestrictionsLoaded
2824          *
2825          * @return bool Whether or not the page's restrictions have already been
2826          * loaded from the database
2827          * @since 1.23
2828          */
2829         public function areRestrictionsLoaded() {
2830                 return $this->mRestrictionsLoaded;
2831         }
2832
2833         /**
2834          * Accessor/initialisation for mRestrictions
2835          *
2836          * @param string $action Action that permission needs to be checked for
2837          * @return array Restriction levels needed to take the action. All levels are
2838          *     required. Note that restriction levels are normally user rights, but 'sysop'
2839          *     and 'autoconfirmed' are also allowed for backwards compatibility. These should
2840          *     be mapped to 'editprotected' and 'editsemiprotected' respectively.
2841          */
2842         public function getRestrictions( $action ) {
2843                 if ( !$this->mRestrictionsLoaded ) {
2844                         $this->loadRestrictions();
2845                 }
2846                 return isset( $this->mRestrictions[$action] )
2847                                 ? $this->mRestrictions[$action]
2848                                 : [];
2849         }
2850
2851         /**
2852          * Accessor/initialisation for mRestrictions
2853          *
2854          * @return array Keys are actions, values are arrays as returned by
2855          *     Title::getRestrictions()
2856          * @since 1.23
2857          */
2858         public function getAllRestrictions() {
2859                 if ( !$this->mRestrictionsLoaded ) {
2860                         $this->loadRestrictions();
2861                 }
2862                 return $this->mRestrictions;
2863         }
2864
2865         /**
2866          * Get the expiry time for the restriction against a given action
2867          *
2868          * @param string $action
2869          * @return string|bool 14-char timestamp, or 'infinity' if the page is protected forever
2870          *     or not protected at all, or false if the action is not recognised.
2871          */
2872         public function getRestrictionExpiry( $action ) {
2873                 if ( !$this->mRestrictionsLoaded ) {
2874                         $this->loadRestrictions();
2875                 }
2876                 return isset( $this->mRestrictionsExpiry[$action] ) ? $this->mRestrictionsExpiry[$action] : false;
2877         }
2878
2879         /**
2880          * Returns cascading restrictions for the current article
2881          *
2882          * @return bool
2883          */
2884         function areRestrictionsCascading() {
2885                 if ( !$this->mRestrictionsLoaded ) {
2886                         $this->loadRestrictions();
2887                 }
2888
2889                 return $this->mCascadeRestriction;
2890         }
2891
2892         /**
2893          * Loads a string into mRestrictions array
2894          *
2895          * @param ResultWrapper $res Resource restrictions as an SQL result.
2896          * @param string $oldFashionedRestrictions Comma-separated list of page
2897          *        restrictions from page table (pre 1.10)
2898          */
2899         private function loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions = null ) {
2900                 $rows = [];
2901
2902                 foreach ( $res as $row ) {
2903                         $rows[] = $row;
2904                 }
2905
2906                 $this->loadRestrictionsFromRows( $rows, $oldFashionedRestrictions );
2907         }
2908
2909         /**
2910          * Compiles list of active page restrictions from both page table (pre 1.10)
2911          * and page_restrictions table for this existing page.
2912          * Public for usage by LiquidThreads.
2913          *
2914          * @param array $rows Array of db result objects
2915          * @param string $oldFashionedRestrictions Comma-separated list of page
2916          *   restrictions from page table (pre 1.10)
2917          */
2918         public function loadRestrictionsFromRows( $rows, $oldFashionedRestrictions = null ) {
2919                 $dbr = wfGetDB( DB_SLAVE );
2920
2921                 $restrictionTypes = $this->getRestrictionTypes();
2922
2923                 foreach ( $restrictionTypes as $type ) {
2924                         $this->mRestrictions[$type] = [];
2925                         $this->mRestrictionsExpiry[$type] = 'infinity';
2926                 }
2927
2928                 $this->mCascadeRestriction = false;
2929
2930                 # Backwards-compatibility: also load the restrictions from the page record (old format).
2931                 if ( $oldFashionedRestrictions !== null ) {
2932                         $this->mOldRestrictions = $oldFashionedRestrictions;
2933                 }
2934
2935                 if ( $this->mOldRestrictions === false ) {
2936                         $this->mOldRestrictions = $dbr->selectField( 'page', 'page_restrictions',
2937                                 [ 'page_id' => $this->getArticleID() ], __METHOD__ );
2938                 }
2939
2940                 if ( $this->mOldRestrictions != '' ) {
2941                         foreach ( explode( ':', trim( $this->mOldRestrictions ) ) as $restrict ) {
2942                                 $temp = explode( '=', trim( $restrict ) );
2943                                 if ( count( $temp ) == 1 ) {
2944                                         // old old format should be treated as edit/move restriction
2945                                         $this->mRestrictions['edit'] = explode( ',', trim( $temp[0] ) );
2946                                         $this->mRestrictions['move'] = explode( ',', trim( $temp[0] ) );
2947                                 } else {
2948                                         $restriction = trim( $temp[1] );
2949                                         if ( $restriction != '' ) { // some old entries are empty
2950                                                 $this->mRestrictions[$temp[0]] = explode( ',', $restriction );
2951                                         }
2952                                 }
2953                         }
2954                 }
2955
2956                 if ( count( $rows ) ) {
2957                         # Current system - load second to make them override.
2958                         $now = wfTimestampNow();
2959
2960                         # Cycle through all the restrictions.
2961                         foreach ( $rows as $row ) {
2962
2963                                 // Don't take care of restrictions types that aren't allowed
2964                                 if ( !in_array( $row->pr_type, $restrictionTypes ) ) {
2965                                         continue;
2966                                 }
2967
2968                                 // This code should be refactored, now that it's being used more generally,
2969                                 // But I don't really see any harm in leaving it in Block for now -werdna
2970                                 $expiry = $dbr->decodeExpiry( $row->pr_expiry );
2971
2972                                 // Only apply the restrictions if they haven't expired!
2973                                 if ( !$expiry || $expiry > $now ) {
2974                                         $this->mRestrictionsExpiry[$row->pr_type] = $expiry;
2975                                         $this->mRestrictions[$row->pr_type] = explode( ',', trim( $row->pr_level ) );
2976
2977                                         $this->mCascadeRestriction |= $row->pr_cascade;
2978                                 }
2979                         }
2980                 }
2981
2982                 $this->mRestrictionsLoaded = true;
2983         }
2984
2985         /**
2986          * Load restrictions from the page_restrictions table
2987          *
2988          * @param string $oldFashionedRestrictions Comma-separated list of page
2989          *   restrictions from page table (pre 1.10)
2990          */
2991         public function loadRestrictions( $oldFashionedRestrictions = null ) {
2992                 if ( !$this->mRestrictionsLoaded ) {
2993                         $dbr = wfGetDB( DB_SLAVE );
2994                         if ( $this->exists() ) {
2995                                 $res = $dbr->select(
2996                                         'page_restrictions',
2997                                         [ 'pr_type', 'pr_expiry', 'pr_level', 'pr_cascade' ],
2998                                         [ 'pr_page' => $this->getArticleID() ],
2999                                         __METHOD__
3000                                 );
3001
3002                                 $this->loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions );
3003                         } else {
3004                                 $title_protection = $this->getTitleProtection();
3005
3006                                 if ( $title_protection ) {
3007                                         $now = wfTimestampNow();
3008                                         $expiry = $dbr->decodeExpiry( $title_protection['expiry'] );
3009
3010                                         if ( !$expiry || $expiry > $now ) {
3011                                                 // Apply the restrictions
3012                                                 $this->mRestrictionsExpiry['create'] = $expiry;
3013                                                 $this->mRestrictions['create'] = explode( ',', trim( $title_protection['permission'] ) );
3014                                         } else { // Get rid of the old restrictions
3015                                                 $this->mTitleProtection = false;
3016                                         }
3017                                 } else {
3018                                         $this->mRestrictionsExpiry['create'] = 'infinity';
3019                                 }
3020                                 $this->mRestrictionsLoaded = true;
3021                         }
3022                 }
3023         }
3024
3025         /**
3026          * Flush the protection cache in this object and force reload from the database.
3027          * This is used when updating protection from WikiPage::doUpdateRestrictions().
3028          */
3029         public function flushRestrictions() {
3030                 $this->mRestrictionsLoaded = false;
3031                 $this->mTitleProtection = null;
3032         }
3033
3034         /**
3035          * Purge expired restrictions from the page_restrictions table
3036          */
3037         static function purgeExpiredRestrictions() {
3038                 if ( wfReadOnly() ) {
3039                         return;
3040                 }
3041
3042                 DeferredUpdates::addUpdate( new AtomicSectionUpdate(
3043                         wfGetDB( DB_MASTER ),
3044                         __METHOD__,
3045                         function ( IDatabase $dbw, $fname ) {
3046                                 $dbw->delete(
3047                                         'page_restrictions',
3048                                         [ 'pr_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ],
3049                                         $fname
3050                                 );
3051                                 $dbw->delete(
3052                                         'protected_titles',
3053                                         [ 'pt_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ],
3054                                         $fname
3055                                 );
3056                         }
3057                 ) );
3058         }
3059
3060         /**
3061          * Does this have subpages?  (Warning, usually requires an extra DB query.)
3062          *
3063          * @return bool
3064          */
3065         public function hasSubpages() {
3066                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
3067                         # Duh
3068                         return false;
3069                 }
3070
3071                 # We dynamically add a member variable for the purpose of this method
3072                 # alone to cache the result.  There's no point in having it hanging
3073                 # around uninitialized in every Title object; therefore we only add it
3074                 # if needed and don't declare it statically.
3075                 if ( $this->mHasSubpages === null ) {
3076                         $this->mHasSubpages = false;
3077                         $subpages = $this->getSubpages( 1 );
3078                         if ( $subpages instanceof TitleArray ) {
3079                                 $this->mHasSubpages = (bool)$subpages->count();
3080                         }
3081                 }
3082
3083                 return $this->mHasSubpages;
3084         }
3085
3086         /**
3087          * Get all subpages of this page.
3088          *
3089          * @param int $limit Maximum number of subpages to fetch; -1 for no limit
3090          * @return TitleArray|array TitleArray, or empty array if this page's namespace
3091          *  doesn't allow subpages
3092          */
3093         public function getSubpages( $limit = -1 ) {
3094                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3095                         return [];
3096                 }
3097
3098                 $dbr = wfGetDB( DB_SLAVE );
3099                 $conds['page_namespace'] = $this->getNamespace();
3100                 $conds[] = 'page_title ' . $dbr->buildLike( $this->getDBkey() . '/', $dbr->anyString() );
3101                 $options = [];
3102                 if ( $limit > -1 ) {
3103                         $options['LIMIT'] = $limit;
3104                 }
3105                 $this->mSubpages = TitleArray::newFromResult(
3106                         $dbr->select( 'page',
3107                                 [ 'page_id', 'page_namespace', 'page_title', 'page_is_redirect' ],
3108                                 $conds,
3109                                 __METHOD__,
3110                                 $options
3111                         )
3112                 );
3113                 return $this->mSubpages;
3114         }
3115
3116         /**
3117          * Is there a version of this page in the deletion archive?
3118          *
3119          * @return int The number of archived revisions
3120          */
3121         public function isDeleted() {
3122                 if ( $this->getNamespace() < 0 ) {
3123                         $n = 0;
3124                 } else {
3125                         $dbr = wfGetDB( DB_SLAVE );
3126
3127                         $n = $dbr->selectField( 'archive', 'COUNT(*)',
3128                                 [ 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ],
3129                                 __METHOD__
3130                         );
3131                         if ( $this->getNamespace() == NS_FILE ) {
3132                                 $n += $dbr->selectField( 'filearchive', 'COUNT(*)',
3133                                         [ 'fa_name' => $this->getDBkey() ],
3134                                         __METHOD__
3135                                 );
3136                         }
3137                 }
3138                 return (int)$n;
3139         }
3140
3141         /**
3142          * Is there a version of this page in the deletion archive?
3143          *
3144          * @return bool
3145          */
3146         public function isDeletedQuick() {
3147                 if ( $this->getNamespace() < 0 ) {
3148                         return false;
3149                 }
3150                 $dbr = wfGetDB( DB_SLAVE );
3151                 $deleted = (bool)$dbr->selectField( 'archive', '1',
3152                         [ 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ],
3153                         __METHOD__
3154                 );
3155                 if ( !$deleted && $this->getNamespace() == NS_FILE ) {
3156                         $deleted = (bool)$dbr->selectField( 'filearchive', '1',
3157                                 [ 'fa_name' => $this->getDBkey() ],
3158                                 __METHOD__
3159                         );
3160                 }
3161                 return $deleted;
3162         }
3163
3164         /**
3165          * Get the article ID for this Title from the link cache,
3166          * adding it if necessary
3167          *
3168          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select
3169          *  for update
3170          * @return int The ID
3171          */
3172         public function getArticleID( $flags = 0 ) {
3173                 if ( $this->getNamespace() < 0 ) {
3174                         $this->mArticleID = 0;
3175                         return $this->mArticleID;
3176                 }
3177                 $linkCache = LinkCache::singleton();
3178                 if ( $flags & self::GAID_FOR_UPDATE ) {
3179                         $oldUpdate = $linkCache->forUpdate( true );
3180                         $linkCache->clearLink( $this );
3181                         $this->mArticleID = $linkCache->addLinkObj( $this );
3182                         $linkCache->forUpdate( $oldUpdate );
3183                 } else {
3184                         if ( -1 == $this->mArticleID ) {
3185                                 $this->mArticleID = $linkCache->addLinkObj( $this );
3186                         }
3187                 }
3188                 return $this->mArticleID;
3189         }
3190
3191         /**
3192          * Is this an article that is a redirect page?
3193          * Uses link cache, adding it if necessary
3194          *
3195          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3196          * @return bool
3197          */
3198         public function isRedirect( $flags = 0 ) {
3199                 if ( !is_null( $this->mRedirect ) ) {
3200                         return $this->mRedirect;
3201                 }
3202                 if ( !$this->getArticleID( $flags ) ) {
3203                         $this->mRedirect = false;
3204                         return $this->mRedirect;
3205                 }
3206
3207                 $linkCache = LinkCache::singleton();
3208                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3209                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'redirect' );
3210                 if ( $cached === null ) {
3211                         # Trust LinkCache's state over our own
3212                         # LinkCache is telling us that the page doesn't exist, despite there being cached
3213                         # data relating to an existing page in $this->mArticleID. Updaters should clear
3214                         # LinkCache as appropriate, or use $flags = Title::GAID_FOR_UPDATE. If that flag is
3215                         # set, then LinkCache will definitely be up to date here, since getArticleID() forces
3216                         # LinkCache to refresh its data from the master.
3217                         $this->mRedirect = false;
3218                         return $this->mRedirect;
3219                 }
3220
3221                 $this->mRedirect = (bool)$cached;
3222
3223                 return $this->mRedirect;
3224         }
3225
3226         /**
3227          * What is the length of this page?
3228          * Uses link cache, adding it if necessary
3229          *
3230          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3231          * @return int
3232          */
3233         public function getLength( $flags = 0 ) {
3234                 if ( $this->mLength != -1 ) {
3235                         return $this->mLength;
3236                 }
3237                 if ( !$this->getArticleID( $flags ) ) {
3238                         $this->mLength = 0;
3239                         return $this->mLength;
3240                 }
3241                 $linkCache = LinkCache::singleton();
3242                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3243                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'length' );
3244                 if ( $cached === null ) {
3245                         # Trust LinkCache's state over our own, as for isRedirect()
3246                         $this->mLength = 0;
3247                         return $this->mLength;
3248                 }
3249
3250                 $this->mLength = intval( $cached );
3251
3252                 return $this->mLength;
3253         }
3254
3255         /**
3256          * What is the page_latest field for this page?
3257          *
3258          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3259          * @return int Int or 0 if the page doesn't exist
3260          */
3261         public function getLatestRevID( $flags = 0 ) {
3262                 if ( !( $flags & Title::GAID_FOR_UPDATE ) && $this->mLatestID !== false ) {
3263                         return intval( $this->mLatestID );
3264                 }
3265                 if ( !$this->getArticleID( $flags ) ) {
3266                         $this->mLatestID = 0;
3267                         return $this->mLatestID;
3268                 }
3269                 $linkCache = LinkCache::singleton();
3270                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3271                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'revision' );
3272                 if ( $cached === null ) {
3273                         # Trust LinkCache's state over our own, as for isRedirect()
3274                         $this->mLatestID = 0;
3275                         return $this->mLatestID;
3276                 }
3277
3278                 $this->mLatestID = intval( $cached );
3279
3280                 return $this->mLatestID;
3281         }
3282
3283         /**
3284          * This clears some fields in this object, and clears any associated
3285          * keys in the "bad links" section of the link cache.
3286          *
3287          * - This is called from WikiPage::doEdit() and WikiPage::insertOn() to allow
3288          * loading of the new page_id. It's also called from
3289          * WikiPage::doDeleteArticleReal()
3290          *
3291          * @param int $newid The new Article ID
3292          */
3293         public function resetArticleID( $newid ) {
3294                 $linkCache = LinkCache::singleton();
3295                 $linkCache->clearLink( $this );
3296
3297                 if ( $newid === false ) {
3298                         $this->mArticleID = -1;
3299                 } else {
3300                         $this->mArticleID = intval( $newid );
3301                 }
3302                 $this->mRestrictionsLoaded = false;
3303                 $this->mRestrictions = [];
3304                 $this->mOldRestrictions = false;
3305                 $this->mRedirect = null;
3306                 $this->mLength = -1;
3307                 $this->mLatestID = false;
3308                 $this->mContentModel = false;
3309                 $this->mEstimateRevisions = null;
3310                 $this->mPageLanguage = false;
3311                 $this->mDbPageLanguage = false;
3312                 $this->mIsBigDeletion = null;
3313         }
3314
3315         public static function clearCaches() {
3316                 $linkCache = LinkCache::singleton();
3317                 $linkCache->clear();
3318
3319                 $titleCache = self::getTitleCache();
3320                 $titleCache->clear();
3321         }
3322
3323         /**
3324          * Capitalize a text string for a title if it belongs to a namespace that capitalizes
3325          *
3326          * @param string $text Containing title to capitalize
3327          * @param int $ns Namespace index, defaults to NS_MAIN
3328          * @return string Containing capitalized title
3329          */
3330         public static function capitalize( $text, $ns = NS_MAIN ) {
3331                 global $wgContLang;
3332
3333                 if ( MWNamespace::isCapitalized( $ns ) ) {
3334                         return $wgContLang->ucfirst( $text );
3335                 } else {
3336                         return $text;
3337                 }
3338         }
3339
3340         /**
3341          * Secure and split - main initialisation function for this object
3342          *
3343          * Assumes that mDbkeyform has been set, and is urldecoded
3344          * and uses underscores, but not otherwise munged.  This function
3345          * removes illegal characters, splits off the interwiki and
3346          * namespace prefixes, sets the other forms, and canonicalizes
3347          * everything.
3348          *
3349          * @throws MalformedTitleException On invalid titles
3350          * @return bool True on success
3351          */
3352         private function secureAndSplit() {
3353                 # Initialisation
3354                 $this->mInterwiki = '';
3355                 $this->mFragment = '';
3356                 $this->mNamespace = $this->mDefaultNamespace; # Usually NS_MAIN
3357
3358                 $dbkey = $this->mDbkeyform;
3359
3360                 // @note: splitTitleString() is a temporary hack to allow MediaWikiTitleCodec to share
3361                 //        the parsing code with Title, while avoiding massive refactoring.
3362                 // @todo: get rid of secureAndSplit, refactor parsing code.
3363                 $titleParser = self::getMediaWikiTitleCodec();
3364                 // MalformedTitleException can be thrown here
3365                 $parts = $titleParser->splitTitleString( $dbkey, $this->getDefaultNamespace() );
3366
3367                 # Fill fields
3368                 $this->setFragment( '#' . $parts['fragment'] );
3369                 $this->mInterwiki = $parts['interwiki'];
3370                 $this->mLocalInterwiki = $parts['local_interwiki'];
3371                 $this->mNamespace = $parts['namespace'];
3372                 $this->mUserCaseDBKey = $parts['user_case_dbkey'];
3373
3374                 $this->mDbkeyform = $parts['dbkey'];
3375                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
3376                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
3377
3378                 # We already know that some pages won't be in the database!
3379                 if ( $this->isExternal() || $this->mNamespace == NS_SPECIAL ) {
3380                         $this->mArticleID = 0;
3381                 }
3382
3383                 return true;
3384         }
3385
3386         /**
3387          * Get an array of Title objects linking to this Title
3388          * Also stores the IDs in the link cache.
3389          *
3390          * WARNING: do not use this function on arbitrary user-supplied titles!
3391          * On heavily-used templates it will max out the memory.
3392          *
3393          * @param array $options May be FOR UPDATE
3394          * @param string $table Table name
3395          * @param string $prefix Fields prefix
3396          * @return Title[] Array of Title objects linking here
3397          */
3398         public function getLinksTo( $options = [], $table = 'pagelinks', $prefix = 'pl' ) {
3399                 if ( count( $options ) > 0 ) {
3400                         $db = wfGetDB( DB_MASTER );
3401                 } else {
3402                         $db = wfGetDB( DB_SLAVE );
3403                 }
3404
3405                 $res = $db->select(
3406                         [ 'page', $table ],
3407                         self::getSelectFields(),
3408                         [
3409                                 "{$prefix}_from=page_id",
3410                                 "{$prefix}_namespace" => $this->getNamespace(),
3411                                 "{$prefix}_title" => $this->getDBkey() ],
3412                         __METHOD__,
3413                         $options
3414                 );
3415
3416                 $retVal = [];
3417                 if ( $res->numRows() ) {
3418                         $linkCache = LinkCache::singleton();
3419                         foreach ( $res as $row ) {
3420                                 $titleObj = Title::makeTitle( $row->page_namespace, $row->page_title );
3421                                 if ( $titleObj ) {
3422                                         $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3423                                         $retVal[] = $titleObj;
3424                                 }
3425                         }
3426                 }
3427                 return $retVal;
3428         }
3429
3430         /**
3431          * Get an array of Title objects using this Title as a template
3432          * Also stores the IDs in the link cache.
3433          *
3434          * WARNING: do not use this function on arbitrary user-supplied titles!
3435          * On heavily-used templates it will max out the memory.
3436          *
3437          * @param array $options Query option to Database::select()
3438          * @return Title[] Array of Title the Title objects linking here
3439          */
3440         public function getTemplateLinksTo( $options = [] ) {
3441                 return $this->getLinksTo( $options, 'templatelinks', 'tl' );
3442         }
3443
3444         /**
3445          * Get an array of Title objects linked from this Title
3446          * Also stores the IDs in the link cache.
3447          *
3448          * WARNING: do not use this function on arbitrary user-supplied titles!
3449          * On heavily-used templates it will max out the memory.
3450          *
3451          * @param array $options Query option to Database::select()
3452          * @param string $table Table name
3453          * @param string $prefix Fields prefix
3454          * @return array Array of Title objects linking here
3455          */
3456         public function getLinksFrom( $options = [], $table = 'pagelinks', $prefix = 'pl' ) {
3457                 $id = $this->getArticleID();
3458
3459                 # If the page doesn't exist; there can't be any link from this page
3460                 if ( !$id ) {
3461                         return [];
3462                 }
3463
3464                 $db = wfGetDB( DB_SLAVE );
3465
3466                 $blNamespace = "{$prefix}_namespace";
3467                 $blTitle = "{$prefix}_title";
3468
3469                 $res = $db->select(
3470                         [ $table, 'page' ],
3471                         array_merge(
3472                                 [ $blNamespace, $blTitle ],
3473                                 WikiPage::selectFields()
3474                         ),
3475                         [ "{$prefix}_from" => $id ],
3476                         __METHOD__,
3477                         $options,
3478                         [ 'page' => [
3479                                 'LEFT JOIN',
3480                                 [ "page_namespace=$blNamespace", "page_title=$blTitle" ]
3481                         ] ]
3482                 );
3483
3484                 $retVal = [];
3485                 $linkCache = LinkCache::singleton();
3486                 foreach ( $res as $row ) {
3487                         if ( $row->page_id ) {
3488                                 $titleObj = Title::newFromRow( $row );
3489                         } else {
3490                                 $titleObj = Title::makeTitle( $row->$blNamespace, $row->$blTitle );
3491                                 $linkCache->addBadLinkObj( $titleObj );
3492                         }
3493                         $retVal[] = $titleObj;
3494                 }
3495
3496                 return $retVal;
3497         }
3498
3499         /**
3500          * Get an array of Title objects used on this Title as a template
3501          * Also stores the IDs in the link cache.
3502          *
3503          * WARNING: do not use this function on arbitrary user-supplied titles!
3504          * On heavily-used templates it will max out the memory.
3505          *
3506          * @param array $options May be FOR UPDATE
3507          * @return Title[] Array of Title the Title objects used here
3508          */
3509         public function getTemplateLinksFrom( $options = [] ) {
3510                 return $this->getLinksFrom( $options, 'templatelinks', 'tl' );
3511         }
3512
3513         /**
3514          * Get an array of Title objects referring to non-existent articles linked
3515          * from this page.
3516          *
3517          * @todo check if needed (used only in SpecialBrokenRedirects.php, and
3518          *   should use redirect table in this case).
3519          * @return Title[] Array of Title the Title objects
3520          */
3521         public function getBrokenLinksFrom() {
3522                 if ( $this->getArticleID() == 0 ) {
3523                         # All links from article ID 0 are false positives
3524                         return [];
3525                 }
3526
3527                 $dbr = wfGetDB( DB_SLAVE );
3528                 $res = $dbr->select(
3529                         [ 'page', 'pagelinks' ],
3530                         [ 'pl_namespace', 'pl_title' ],
3531                         [
3532                                 'pl_from' => $this->getArticleID(),
3533                                 'page_namespace IS NULL'
3534                         ],
3535                         __METHOD__, [],
3536                         [
3537                                 'page' => [
3538                                         'LEFT JOIN',
3539                                         [ 'pl_namespace=page_namespace', 'pl_title=page_title' ]
3540                                 ]
3541                         ]
3542                 );
3543
3544                 $retVal = [];
3545                 foreach ( $res as $row ) {
3546                         $retVal[] = Title::makeTitle( $row->pl_namespace, $row->pl_title );
3547                 }
3548                 return $retVal;
3549         }
3550
3551         /**
3552          * Get a list of URLs to purge from the CDN cache when this
3553          * page changes
3554          *
3555          * @return string[] Array of String the URLs
3556          */
3557         public function getCdnUrls() {
3558                 $urls = [
3559                         $this->getInternalURL(),
3560                         $this->getInternalURL( 'action=history' )
3561                 ];
3562
3563                 $pageLang = $this->getPageLanguage();
3564                 if ( $pageLang->hasVariants() ) {
3565                         $variants = $pageLang->getVariants();
3566                         foreach ( $variants as $vCode ) {
3567                                 $urls[] = $this->getInternalURL( $vCode );
3568                         }
3569                 }
3570
3571                 // If we are looking at a css/js user subpage, purge the action=raw.
3572                 if ( $this->isJsSubpage() ) {
3573                         $urls[] = $this->getInternalURL( 'action=raw&ctype=text/javascript' );
3574                 } elseif ( $this->isCssSubpage() ) {
3575                         $urls[] = $this->getInternalURL( 'action=raw&ctype=text/css' );
3576                 }
3577
3578                 Hooks::run( 'TitleSquidURLs', [ $this, &$urls ] );
3579                 return $urls;
3580         }
3581
3582         /**
3583          * @deprecated since 1.27 use getCdnUrls()
3584          */
3585         public function getSquidURLs() {
3586                 return $this->getCdnUrls();
3587         }
3588
3589         /**
3590          * Purge all applicable CDN URLs
3591          */
3592         public function purgeSquid() {
3593                 DeferredUpdates::addUpdate(
3594                         new CdnCacheUpdate( $this->getCdnUrls() ),
3595                         DeferredUpdates::PRESEND
3596                 );
3597         }
3598
3599         /**
3600          * Move this page without authentication
3601          *
3602          * @deprecated since 1.25 use MovePage class instead
3603          * @param Title $nt The new page Title
3604          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3605          */
3606         public function moveNoAuth( &$nt ) {
3607                 wfDeprecated( __METHOD__, '1.25' );
3608                 return $this->moveTo( $nt, false );
3609         }
3610
3611         /**
3612          * Check whether a given move operation would be valid.
3613          * Returns true if ok, or a getUserPermissionsErrors()-like array otherwise
3614          *
3615          * @deprecated since 1.25, use MovePage's methods instead
3616          * @param Title $nt The new title
3617          * @param bool $auth Whether to check user permissions (uses $wgUser)
3618          * @param string $reason Is the log summary of the move, used for spam checking
3619          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3620          */
3621         public function isValidMoveOperation( &$nt, $auth = true, $reason = '' ) {
3622                 global $wgUser;
3623
3624                 if ( !( $nt instanceof Title ) ) {
3625                         // Normally we'd add this to $errors, but we'll get
3626                         // lots of syntax errors if $nt is not an object
3627                         return [ [ 'badtitletext' ] ];
3628                 }
3629
3630                 $mp = new MovePage( $this, $nt );
3631                 $errors = $mp->isValidMove()->getErrorsArray();
3632                 if ( $auth ) {
3633                         $errors = wfMergeErrorArrays(
3634                                 $errors,
3635                                 $mp->checkPermissions( $wgUser, $reason )->getErrorsArray()
3636                         );
3637                 }
3638
3639                 return $errors ?: true;
3640         }
3641
3642         /**
3643          * Check if the requested move target is a valid file move target
3644          * @todo move this to MovePage
3645          * @param Title $nt Target title
3646          * @return array List of errors
3647          */
3648         protected function validateFileMoveOperation( $nt ) {
3649                 global $wgUser;
3650
3651                 $errors = [];
3652
3653                 $destFile = wfLocalFile( $nt );
3654                 $destFile->load( File::READ_LATEST );
3655                 if ( !$wgUser->isAllowed( 'reupload-shared' )
3656                         && !$destFile->exists() && wfFindFile( $nt )
3657                 ) {
3658                         $errors[] = [ 'file-exists-sharedrepo' ];
3659                 }
3660
3661                 return $errors;
3662         }
3663
3664         /**
3665          * Move a title to a new location
3666          *
3667          * @deprecated since 1.25, use the MovePage class instead
3668          * @param Title $nt The new title
3669          * @param bool $auth Indicates whether $wgUser's permissions
3670          *  should be checked
3671          * @param string $reason The reason for the move
3672          * @param bool $createRedirect Whether to create a redirect from the old title to the new title.
3673          *  Ignored if the user doesn't have the suppressredirect right.
3674          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3675          */
3676         public function moveTo( &$nt, $auth = true, $reason = '', $createRedirect = true ) {
3677                 global $wgUser;
3678                 $err = $this->isValidMoveOperation( $nt, $auth, $reason );
3679                 if ( is_array( $err ) ) {
3680                         // Auto-block user's IP if the account was "hard" blocked
3681                         $wgUser->spreadAnyEditBlock();
3682                         return $err;
3683                 }
3684                 // Check suppressredirect permission
3685                 if ( $auth && !$wgUser->isAllowed( 'suppressredirect' ) ) {
3686                         $createRedirect = true;
3687                 }
3688
3689                 $mp = new MovePage( $this, $nt );
3690                 $status = $mp->move( $wgUser, $reason, $createRedirect );
3691                 if ( $status->isOK() ) {
3692                         return true;
3693                 } else {
3694                         return $status->getErrorsArray();
3695                 }
3696         }
3697
3698         /**
3699          * Move this page's subpages to be subpages of $nt
3700          *
3701          * @param Title $nt Move target
3702          * @param bool $auth Whether $wgUser's permissions should be checked
3703          * @param string $reason The reason for the move
3704          * @param bool $createRedirect Whether to create redirects from the old subpages to
3705          *     the new ones Ignored if the user doesn't have the 'suppressredirect' right
3706          * @return array Array with old page titles as keys, and strings (new page titles) or
3707          *     arrays (errors) as values, or an error array with numeric indices if no pages
3708          *     were moved
3709          */
3710         public function moveSubpages( $nt, $auth = true, $reason = '', $createRedirect = true ) {
3711                 global $wgMaximumMovedPages;
3712                 // Check permissions
3713                 if ( !$this->userCan( 'move-subpages' ) ) {
3714                         return [ 'cant-move-subpages' ];
3715                 }
3716                 // Do the source and target namespaces support subpages?
3717                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3718                         return [ 'namespace-nosubpages',
3719                                 MWNamespace::getCanonicalName( $this->getNamespace() ) ];
3720                 }
3721                 if ( !MWNamespace::hasSubpages( $nt->getNamespace() ) ) {
3722                         return [ 'namespace-nosubpages',
3723                                 MWNamespace::getCanonicalName( $nt->getNamespace() ) ];
3724                 }
3725
3726                 $subpages = $this->getSubpages( $wgMaximumMovedPages + 1 );
3727                 $retval = [];
3728                 $count = 0;
3729                 foreach ( $subpages as $oldSubpage ) {
3730                         $count++;
3731                         if ( $count > $wgMaximumMovedPages ) {
3732                                 $retval[$oldSubpage->getPrefixedText()] =
3733                                                 [ 'movepage-max-pages',
3734                                                         $wgMaximumMovedPages ];
3735                                 break;
3736                         }
3737
3738                         // We don't know whether this function was called before
3739                         // or after moving the root page, so check both
3740                         // $this and $nt
3741                         if ( $oldSubpage->getArticleID() == $this->getArticleID()
3742                                 || $oldSubpage->getArticleID() == $nt->getArticleID()
3743                         ) {
3744                                 // When moving a page to a subpage of itself,
3745                                 // don't move it twice
3746                                 continue;
3747                         }
3748                         $newPageName = preg_replace(
3749                                         '#^' . preg_quote( $this->getDBkey(), '#' ) . '#',
3750                                         StringUtils::escapeRegexReplacement( $nt->getDBkey() ), # bug 21234
3751                                         $oldSubpage->getDBkey() );
3752                         if ( $oldSubpage->isTalkPage() ) {
3753                                 $newNs = $nt->getTalkPage()->getNamespace();
3754                         } else {
3755                                 $newNs = $nt->getSubjectPage()->getNamespace();
3756                         }
3757                         # Bug 14385: we need makeTitleSafe because the new page names may
3758                         # be longer than 255 characters.
3759                         $newSubpage = Title::makeTitleSafe( $newNs, $newPageName );
3760
3761                         $success = $oldSubpage->moveTo( $newSubpage, $auth, $reason, $createRedirect );
3762                         if ( $success === true ) {
3763                                 $retval[$oldSubpage->getPrefixedText()] = $newSubpage->getPrefixedText();
3764                         } else {
3765                                 $retval[$oldSubpage->getPrefixedText()] = $success;
3766                         }
3767                 }
3768                 return $retval;
3769         }
3770
3771         /**
3772          * Checks if this page is just a one-rev redirect.
3773          * Adds lock, so don't use just for light purposes.
3774          *
3775          * @return bool
3776          */
3777         public function isSingleRevRedirect() {
3778                 global $wgContentHandlerUseDB;
3779
3780                 $dbw = wfGetDB( DB_MASTER );
3781
3782                 # Is it a redirect?
3783                 $fields = [ 'page_is_redirect', 'page_latest', 'page_id' ];
3784                 if ( $wgContentHandlerUseDB ) {
3785                         $fields[] = 'page_content_model';
3786                 }
3787
3788                 $row = $dbw->selectRow( 'page',
3789                         $fields,
3790                         $this->pageCond(),
3791                         __METHOD__,
3792                         [ 'FOR UPDATE' ]
3793                 );
3794                 # Cache some fields we may want
3795                 $this->mArticleID = $row ? intval( $row->page_id ) : 0;
3796                 $this->mRedirect = $row ? (bool)$row->page_is_redirect : false;
3797                 $this->mLatestID = $row ? intval( $row->page_latest ) : false;
3798                 $this->mContentModel = $row && isset( $row->page_content_model )
3799                         ? strval( $row->page_content_model )
3800                         : false;
3801
3802                 if ( !$this->mRedirect ) {
3803                         return false;
3804                 }
3805                 # Does the article have a history?
3806                 $row = $dbw->selectField( [ 'page', 'revision' ],
3807                         'rev_id',
3808                         [ 'page_namespace' => $this->getNamespace(),
3809                                 'page_title' => $this->getDBkey(),
3810                                 'page_id=rev_page',
3811                                 'page_latest != rev_id'
3812                         ],
3813                         __METHOD__,
3814                         [ 'FOR UPDATE' ]
3815                 );
3816                 # Return true if there was no history
3817                 return ( $row === false );
3818         }
3819
3820         /**
3821          * Checks if $this can be moved to a given Title
3822          * - Selects for update, so don't call it unless you mean business
3823          *
3824          * @deprecated since 1.25, use MovePage's methods instead
3825          * @param Title $nt The new title to check
3826          * @return bool
3827          */
3828         public function isValidMoveTarget( $nt ) {
3829                 # Is it an existing file?
3830                 if ( $nt->getNamespace() == NS_FILE ) {
3831                         $file = wfLocalFile( $nt );
3832                         $file->load( File::READ_LATEST );
3833                         if ( $file->exists() ) {
3834                                 wfDebug( __METHOD__ . ": file exists\n" );
3835                                 return false;
3836                         }
3837                 }
3838                 # Is it a redirect with no history?
3839                 if ( !$nt->isSingleRevRedirect() ) {
3840                         wfDebug( __METHOD__ . ": not a one-rev redirect\n" );
3841                         return false;
3842                 }
3843                 # Get the article text
3844                 $rev = Revision::newFromTitle( $nt, false, Revision::READ_LATEST );
3845                 if ( !is_object( $rev ) ) {
3846                         return false;
3847                 }
3848                 $content = $rev->getContent();
3849                 # Does the redirect point to the source?
3850                 # Or is it a broken self-redirect, usually caused by namespace collisions?
3851                 $redirTitle = $content ? $content->getRedirectTarget() : null;
3852
3853                 if ( $redirTitle ) {
3854                         if ( $redirTitle->getPrefixedDBkey() != $this->getPrefixedDBkey() &&
3855                                 $redirTitle->getPrefixedDBkey() != $nt->getPrefixedDBkey() ) {
3856                                 wfDebug( __METHOD__ . ": redirect points to other page\n" );
3857                                 return false;
3858                         } else {
3859                                 return true;
3860                         }
3861                 } else {
3862                         # Fail safe (not a redirect after all. strange.)
3863                         wfDebug( __METHOD__ . ": failsafe: database sais " . $nt->getPrefixedDBkey() .
3864                                                 " is a redirect, but it doesn't contain a valid redirect.\n" );
3865                         return false;
3866                 }
3867         }
3868
3869         /**
3870          * Get categories to which this Title belongs and return an array of
3871          * categories' names.
3872          *
3873          * @return array Array of parents in the form:
3874          *        $parent => $currentarticle
3875          */
3876         public function getParentCategories() {
3877                 global $wgContLang;
3878
3879                 $data = [];
3880
3881                 $titleKey = $this->getArticleID();
3882
3883                 if ( $titleKey === 0 ) {
3884                         return $data;
3885                 }
3886
3887                 $dbr = wfGetDB( DB_SLAVE );
3888
3889                 $res = $dbr->select(
3890                         'categorylinks',
3891                         'cl_to',
3892                         [ 'cl_from' => $titleKey ],
3893                         __METHOD__
3894                 );
3895
3896                 if ( $res->numRows() > 0 ) {
3897                         foreach ( $res as $row ) {
3898                                 // $data[] = Title::newFromText($wgContLang->getNsText ( NS_CATEGORY ).':'.$row->cl_to);
3899                                 $data[$wgContLang->getNsText( NS_CATEGORY ) . ':' . $row->cl_to] = $this->getFullText();
3900                         }
3901                 }
3902                 return $data;
3903         }
3904
3905         /**
3906          * Get a tree of parent categories
3907          *
3908          * @param array $children Array with the children in the keys, to check for circular refs
3909          * @return array Tree of parent categories
3910          */
3911         public function getParentCategoryTree( $children = [] ) {
3912                 $stack = [];
3913                 $parents = $this->getParentCategories();
3914
3915                 if ( $parents ) {
3916                         foreach ( $parents as $parent => $current ) {
3917                                 if ( array_key_exists( $parent, $children ) ) {
3918                                         # Circular reference
3919                                         $stack[$parent] = [];
3920                                 } else {
3921                                         $nt = Title::newFromText( $parent );
3922                                         if ( $nt ) {
3923                                                 $stack[$parent] = $nt->getParentCategoryTree( $children + [ $parent => 1 ] );
3924                                         }
3925                                 }
3926                         }
3927                 }
3928
3929                 return $stack;
3930         }
3931
3932         /**
3933          * Get an associative array for selecting this title from
3934          * the "page" table
3935          *
3936          * @return array Array suitable for the $where parameter of DB::select()
3937          */
3938         public function pageCond() {
3939                 if ( $this->mArticleID > 0 ) {
3940                         // PK avoids secondary lookups in InnoDB, shouldn't hurt other DBs
3941                         return [ 'page_id' => $this->mArticleID ];
3942                 } else {
3943                         return [ 'page_namespace' => $this->mNamespace, 'page_title' => $this->mDbkeyform ];
3944                 }
3945         }
3946
3947         /**
3948          * Get the revision ID of the previous revision
3949          *
3950          * @param int $revId Revision ID. Get the revision that was before this one.
3951          * @param int $flags Title::GAID_FOR_UPDATE
3952          * @return int|bool Old revision ID, or false if none exists
3953          */
3954         public function getPreviousRevisionID( $revId, $flags = 0 ) {
3955                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
3956                 $revId = $db->selectField( 'revision', 'rev_id',
3957                         [
3958                                 'rev_page' => $this->getArticleID( $flags ),
3959                                 'rev_id < ' . intval( $revId )
3960                         ],
3961                         __METHOD__,
3962                         [ 'ORDER BY' => 'rev_id DESC' ]
3963                 );
3964
3965                 if ( $revId === false ) {
3966                         return false;
3967                 } else {
3968                         return intval( $revId );
3969                 }
3970         }
3971
3972         /**
3973          * Get the revision ID of the next revision
3974          *
3975          * @param int $revId Revision ID. Get the revision that was after this one.
3976          * @param int $flags Title::GAID_FOR_UPDATE
3977          * @return int|bool Next revision ID, or false if none exists
3978          */
3979         public function getNextRevisionID( $revId, $flags = 0 ) {
3980                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
3981                 $revId = $db->selectField( 'revision', 'rev_id',
3982                         [
3983                                 'rev_page' => $this->getArticleID( $flags ),
3984                                 'rev_id > ' . intval( $revId )
3985                         ],
3986                         __METHOD__,
3987                         [ 'ORDER BY' => 'rev_id' ]
3988                 );
3989
3990                 if ( $revId === false ) {
3991                         return false;
3992                 } else {
3993                         return intval( $revId );
3994                 }
3995         }
3996
3997         /**
3998          * Get the first revision of the page
3999          *
4000          * @param int $flags Title::GAID_FOR_UPDATE
4001          * @return Revision|null If page doesn't exist
4002          */
4003         public function getFirstRevision( $flags = 0 ) {
4004                 $pageId = $this->getArticleID( $flags );
4005                 if ( $pageId ) {
4006                         $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
4007                         $row = $db->selectRow( 'revision', Revision::selectFields(),
4008                                 [ 'rev_page' => $pageId ],
4009                                 __METHOD__,
4010                                 [ 'ORDER BY' => 'rev_timestamp ASC', 'LIMIT' => 1 ]
4011                         );
4012                         if ( $row ) {
4013                                 return new Revision( $row );
4014                         }
4015                 }
4016                 return null;
4017         }
4018
4019         /**
4020          * Get the oldest revision timestamp of this page
4021          *
4022          * @param int $flags Title::GAID_FOR_UPDATE
4023          * @return string MW timestamp
4024          */
4025         public function getEarliestRevTime( $flags = 0 ) {
4026                 $rev = $this->getFirstRevision( $flags );
4027                 return $rev ? $rev->getTimestamp() : null;
4028         }
4029
4030         /**
4031          * Check if this is a new page
4032          *
4033          * @return bool
4034          */
4035         public function isNewPage() {
4036                 $dbr = wfGetDB( DB_SLAVE );
4037                 return (bool)$dbr->selectField( 'page', 'page_is_new', $this->pageCond(), __METHOD__ );
4038         }
4039
4040         /**
4041          * Check whether the number of revisions of this page surpasses $wgDeleteRevisionsLimit
4042          *
4043          * @return bool
4044          */
4045         public function isBigDeletion() {
4046                 global $wgDeleteRevisionsLimit;
4047
4048                 if ( !$wgDeleteRevisionsLimit ) {
4049                         return false;
4050                 }
4051
4052                 if ( $this->mIsBigDeletion === null ) {
4053                         $dbr = wfGetDB( DB_SLAVE );
4054
4055                         $revCount = $dbr->selectRowCount(
4056                                 'revision',
4057                                 '1',
4058                                 [ 'rev_page' => $this->getArticleID() ],
4059                                 __METHOD__,
4060                                 [ 'LIMIT' => $wgDeleteRevisionsLimit + 1 ]
4061                         );
4062
4063                         $this->mIsBigDeletion = $revCount > $wgDeleteRevisionsLimit;
4064                 }
4065
4066                 return $this->mIsBigDeletion;
4067         }
4068
4069         /**
4070          * Get the approximate revision count of this page.
4071          *
4072          * @return int
4073          */
4074         public function estimateRevisionCount() {
4075                 if ( !$this->exists() ) {
4076                         return 0;
4077                 }
4078
4079                 if ( $this->mEstimateRevisions === null ) {
4080                         $dbr = wfGetDB( DB_SLAVE );
4081                         $this->mEstimateRevisions = $dbr->estimateRowCount( 'revision', '*',
4082                                 [ 'rev_page' => $this->getArticleID() ], __METHOD__ );
4083                 }
4084
4085                 return $this->mEstimateRevisions;
4086         }
4087
4088         /**
4089          * Get the number of revisions between the given revision.
4090          * Used for diffs and other things that really need it.
4091          *
4092          * @param int|Revision $old Old revision or rev ID (first before range)
4093          * @param int|Revision $new New revision or rev ID (first after range)
4094          * @param int|null $max Limit of Revisions to count, will be incremented to detect truncations
4095          * @return int Number of revisions between these revisions.
4096          */
4097         public function countRevisionsBetween( $old, $new, $max = null ) {
4098                 if ( !( $old instanceof Revision ) ) {
4099                         $old = Revision::newFromTitle( $this, (int)$old );
4100                 }
4101                 if ( !( $new instanceof Revision ) ) {
4102                         $new = Revision::newFromTitle( $this, (int)$new );
4103                 }
4104                 if ( !$old || !$new ) {
4105                         return 0; // nothing to compare
4106                 }
4107                 $dbr = wfGetDB( DB_SLAVE );
4108                 $conds = [
4109                         'rev_page' => $this->getArticleID(),
4110                         'rev_timestamp > ' . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4111                         'rev_timestamp < ' . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4112                 ];
4113                 if ( $max !== null ) {
4114                         return $dbr->selectRowCount( 'revision', '1',
4115                                 $conds,
4116                                 __METHOD__,
4117                                 [ 'LIMIT' => $max + 1 ] // extra to detect truncation
4118                         );
4119                 } else {
4120                         return (int)$dbr->selectField( 'revision', 'count(*)', $conds, __METHOD__ );
4121                 }
4122         }
4123
4124         /**
4125          * Get the authors between the given revisions or revision IDs.
4126          * Used for diffs and other things that really need it.
4127          *
4128          * @since 1.23
4129          *
4130          * @param int|Revision $old Old revision or rev ID (first before range by default)
4131          * @param int|Revision $new New revision or rev ID (first after range by default)
4132          * @param int $limit Maximum number of authors
4133          * @param string|array $options (Optional): Single option, or an array of options:
4134          *     'include_old' Include $old in the range; $new is excluded.
4135          *     'include_new' Include $new in the range; $old is excluded.
4136          *     'include_both' Include both $old and $new in the range.
4137          *     Unknown option values are ignored.
4138          * @return array|null Names of revision authors in the range; null if not both revisions exist
4139          */
4140         public function getAuthorsBetween( $old, $new, $limit, $options = [] ) {
4141                 if ( !( $old instanceof Revision ) ) {
4142                         $old = Revision::newFromTitle( $this, (int)$old );
4143                 }
4144                 if ( !( $new instanceof Revision ) ) {
4145                         $new = Revision::newFromTitle( $this, (int)$new );
4146                 }
4147                 // XXX: what if Revision objects are passed in, but they don't refer to this title?
4148                 // Add $old->getPage() != $new->getPage() || $old->getPage() != $this->getArticleID()
4149                 // in the sanity check below?
4150                 if ( !$old || !$new ) {
4151                         return null; // nothing to compare
4152                 }
4153                 $authors = [];
4154                 $old_cmp = '>';
4155                 $new_cmp = '<';
4156                 $options = (array)$options;
4157                 if ( in_array( 'include_old', $options ) ) {
4158                         $old_cmp = '>=';
4159                 }
4160                 if ( in_array( 'include_new', $options ) ) {
4161                         $new_cmp = '<=';
4162                 }
4163                 if ( in_array( 'include_both', $options ) ) {
4164                         $old_cmp = '>=';
4165                         $new_cmp = '<=';
4166                 }
4167                 // No DB query needed if $old and $new are the same or successive revisions:
4168                 if ( $old->getId() === $new->getId() ) {
4169                         return ( $old_cmp === '>' && $new_cmp === '<' ) ?
4170                                 [] :
4171                                 [ $old->getUserText( Revision::RAW ) ];
4172                 } elseif ( $old->getId() === $new->getParentId() ) {
4173                         if ( $old_cmp === '>=' && $new_cmp === '<=' ) {
4174                                 $authors[] = $old->getUserText( Revision::RAW );
4175                                 if ( $old->getUserText( Revision::RAW ) != $new->getUserText( Revision::RAW ) ) {
4176                                         $authors[] = $new->getUserText( Revision::RAW );
4177                                 }
4178                         } elseif ( $old_cmp === '>=' ) {
4179                                 $authors[] = $old->getUserText( Revision::RAW );
4180                         } elseif ( $new_cmp === '<=' ) {
4181                                 $authors[] = $new->getUserText( Revision::RAW );
4182                         }
4183                         return $authors;
4184                 }
4185                 $dbr = wfGetDB( DB_SLAVE );
4186                 $res = $dbr->select( 'revision', 'DISTINCT rev_user_text',
4187                         [
4188                                 'rev_page' => $this->getArticleID(),
4189                                 "rev_timestamp $old_cmp " . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4190                                 "rev_timestamp $new_cmp " . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4191                         ], __METHOD__,
4192                         [ 'LIMIT' => $limit + 1 ] // add one so caller knows it was truncated
4193                 );
4194                 foreach ( $res as $row ) {
4195                         $authors[] = $row->rev_user_text;
4196                 }
4197                 return $authors;
4198         }
4199
4200         /**
4201          * Get the number of authors between the given revisions or revision IDs.
4202          * Used for diffs and other things that really need it.
4203          *
4204          * @param int|Revision $old Old revision or rev ID (first before range by default)
4205          * @param int|Revision $new New revision or rev ID (first after range by default)
4206          * @param int $limit Maximum number of authors
4207          * @param string|array $options (Optional): Single option, or an array of options:
4208          *     'include_old' Include $old in the range; $new is excluded.
4209          *     'include_new' Include $new in the range; $old is excluded.
4210          *     'include_both' Include both $old and $new in the range.
4211          *     Unknown option values are ignored.
4212          * @return int Number of revision authors in the range; zero if not both revisions exist
4213          */
4214         public function countAuthorsBetween( $old, $new, $limit, $options = [] ) {
4215                 $authors = $this->getAuthorsBetween( $old, $new, $limit, $options );
4216                 return $authors ? count( $authors ) : 0;
4217         }
4218
4219         /**
4220          * Compare with another title.
4221          *
4222          * @param Title $title
4223          * @return bool
4224          */
4225         public function equals( Title $title ) {
4226                 // Note: === is necessary for proper matching of number-like titles.
4227                 return $this->getInterwiki() === $title->getInterwiki()
4228                         && $this->getNamespace() == $title->getNamespace()
4229                         && $this->getDBkey() === $title->getDBkey();
4230         }
4231
4232         /**
4233          * Check if this title is a subpage of another title
4234          *
4235          * @param Title $title
4236          * @return bool
4237          */
4238         public function isSubpageOf( Title $title ) {
4239                 return $this->getInterwiki() === $title->getInterwiki()
4240                         && $this->getNamespace() == $title->getNamespace()
4241                         && strpos( $this->getDBkey(), $title->getDBkey() . '/' ) === 0;
4242         }
4243
4244         /**
4245          * Check if page exists.  For historical reasons, this function simply
4246          * checks for the existence of the title in the page table, and will
4247          * thus return false for interwiki links, special pages and the like.
4248          * If you want to know if a title can be meaningfully viewed, you should
4249          * probably call the isKnown() method instead.
4250          *
4251          * @param int $flags An optional bit field; may be Title::GAID_FOR_UPDATE to check
4252          *   from master/for update
4253          * @return bool
4254          */
4255         public function exists( $flags = 0 ) {
4256                 $exists = $this->getArticleID( $flags ) != 0;
4257                 Hooks::run( 'TitleExists', [ $this, &$exists ] );
4258                 return $exists;
4259         }
4260
4261         /**
4262          * Should links to this title be shown as potentially viewable (i.e. as
4263          * "bluelinks"), even if there's no record by this title in the page
4264          * table?
4265          *
4266          * This function is semi-deprecated for public use, as well as somewhat
4267          * misleadingly named.  You probably just want to call isKnown(), which
4268          * calls this function internally.
4269          *
4270          * (ISSUE: Most of these checks are cheap, but the file existence check
4271          * can potentially be quite expensive.  Including it here fixes a lot of
4272          * existing code, but we might want to add an optional parameter to skip
4273          * it and any other expensive checks.)
4274          *
4275          * @return bool
4276          */
4277         public function isAlwaysKnown() {
4278                 $isKnown = null;
4279
4280                 /**
4281                  * Allows overriding default behavior for determining if a page exists.
4282                  * If $isKnown is kept as null, regular checks happen. If it's
4283                  * a boolean, this value is returned by the isKnown method.
4284                  *
4285                  * @since 1.20
4286                  *
4287                  * @param Title $title
4288                  * @param bool|null $isKnown
4289                  */
4290                 Hooks::run( 'TitleIsAlwaysKnown', [ $this, &$isKnown ] );
4291
4292                 if ( !is_null( $isKnown ) ) {
4293                         return $isKnown;
4294                 }
4295
4296                 if ( $this->isExternal() ) {
4297                         return true;  // any interwiki link might be viewable, for all we know
4298                 }
4299
4300                 switch ( $this->mNamespace ) {
4301                         case NS_MEDIA:
4302                         case NS_FILE:
4303                                 // file exists, possibly in a foreign repo
4304                                 return (bool)wfFindFile( $this );
4305                         case NS_SPECIAL:
4306                                 // valid special page
4307                                 return SpecialPageFactory::exists( $this->getDBkey() );
4308                         case NS_MAIN:
4309                                 // selflink, possibly with fragment
4310                                 return $this->mDbkeyform == '';
4311                         case NS_MEDIAWIKI:
4312                                 // known system message
4313                                 return $this->hasSourceText() !== false;
4314                         default:
4315                                 return false;
4316                 }
4317         }
4318
4319         /**
4320          * Does this title refer to a page that can (or might) be meaningfully
4321          * viewed?  In particular, this function may be used to determine if
4322          * links to the title should be rendered as "bluelinks" (as opposed to
4323          * "redlinks" to non-existent pages).
4324          * Adding something else to this function will cause inconsistency
4325          * since LinkHolderArray calls isAlwaysKnown() and does its own
4326          * page existence check.
4327          *
4328          * @return bool
4329          */
4330         public function isKnown() {
4331                 return $this->isAlwaysKnown() || $this->exists();
4332         }
4333
4334         /**
4335          * Does this page have source text?
4336          *
4337          * @return bool
4338          */
4339         public function hasSourceText() {
4340                 if ( $this->exists() ) {
4341                         return true;
4342                 }
4343
4344                 if ( $this->mNamespace == NS_MEDIAWIKI ) {
4345                         // If the page doesn't exist but is a known system message, default
4346                         // message content will be displayed, same for language subpages-
4347                         // Use always content language to avoid loading hundreds of languages
4348                         // to get the link color.
4349                         global $wgContLang;
4350                         list( $name, ) = MessageCache::singleton()->figureMessage(
4351                                 $wgContLang->lcfirst( $this->getText() )
4352                         );
4353                         $message = wfMessage( $name )->inLanguage( $wgContLang )->useDatabase( false );
4354                         return $message->exists();
4355                 }
4356
4357                 return false;
4358         }
4359
4360         /**
4361          * Get the default message text or false if the message doesn't exist
4362          *
4363          * @return string|bool
4364          */
4365         public function getDefaultMessageText() {
4366                 global $wgContLang;
4367
4368                 if ( $this->getNamespace() != NS_MEDIAWIKI ) { // Just in case
4369                         return false;
4370                 }
4371
4372                 list( $name, $lang ) = MessageCache::singleton()->figureMessage(
4373                         $wgContLang->lcfirst( $this->getText() )
4374                 );
4375                 $message = wfMessage( $name )->inLanguage( $lang )->useDatabase( false );
4376
4377                 if ( $message->exists() ) {
4378                         return $message->plain();
4379                 } else {
4380                         return false;
4381                 }
4382         }
4383
4384         /**
4385          * Updates page_touched for this page; called from LinksUpdate.php
4386          *
4387          * @param string $purgeTime [optional] TS_MW timestamp
4388          * @return bool True if the update succeeded
4389          */
4390         public function invalidateCache( $purgeTime = null ) {
4391                 if ( wfReadOnly() ) {
4392                         return false;
4393                 }
4394
4395                 if ( $this->mArticleID === 0 ) {
4396                         return true; // avoid gap locking if we know it's not there
4397                 }
4398
4399                 $method = __METHOD__;
4400                 $dbw = wfGetDB( DB_MASTER );
4401                 $conds = $this->pageCond();
4402                 $dbw->onTransactionIdle( function () use ( $dbw, $conds, $method, $purgeTime ) {
4403                         $dbTimestamp = $dbw->timestamp( $purgeTime ?: time() );
4404
4405                         $dbw->update(
4406                                 'page',
4407                                 [ 'page_touched' => $dbTimestamp ],
4408                                 $conds + [ 'page_touched < ' . $dbw->addQuotes( $dbTimestamp ) ],
4409                                 $method
4410                         );
4411                 } );
4412
4413                 return true;
4414         }
4415
4416         /**
4417          * Update page_touched timestamps and send CDN purge messages for
4418          * pages linking to this title. May be sent to the job queue depending
4419          * on the number of links. Typically called on create and delete.
4420          */
4421         public function touchLinks() {
4422                 DeferredUpdates::addUpdate( new HTMLCacheUpdate( $this, 'pagelinks' ) );
4423                 if ( $this->getNamespace() == NS_CATEGORY ) {
4424                         DeferredUpdates::addUpdate( new HTMLCacheUpdate( $this, 'categorylinks' ) );
4425                 }
4426         }
4427
4428         /**
4429          * Get the last touched timestamp
4430          *
4431          * @param IDatabase $db Optional db
4432          * @return string Last-touched timestamp
4433          */
4434         public function getTouched( $db = null ) {
4435                 if ( $db === null ) {
4436                         $db = wfGetDB( DB_SLAVE );
4437                 }
4438                 $touched = $db->selectField( 'page', 'page_touched', $this->pageCond(), __METHOD__ );
4439                 return $touched;
4440         }
4441
4442         /**
4443          * Get the timestamp when this page was updated since the user last saw it.
4444          *
4445          * @param User $user
4446          * @return string|null
4447          */
4448         public function getNotificationTimestamp( $user = null ) {
4449                 global $wgUser;
4450
4451                 // Assume current user if none given
4452                 if ( !$user ) {
4453                         $user = $wgUser;
4454                 }
4455                 // Check cache first
4456                 $uid = $user->getId();
4457                 if ( !$uid ) {
4458                         return false;
4459                 }
4460                 // avoid isset here, as it'll return false for null entries
4461                 if ( array_key_exists( $uid, $this->mNotificationTimestamp ) ) {
4462                         return $this->mNotificationTimestamp[$uid];
4463                 }
4464                 // Don't cache too much!
4465                 if ( count( $this->mNotificationTimestamp ) >= self::CACHE_MAX ) {
4466                         $this->mNotificationTimestamp = [];
4467                 }
4468
4469                 $watchedItem = WatchedItemStore::getDefaultInstance()->getWatchedItem( $user, $this );
4470                 if ( $watchedItem ) {
4471                         $this->mNotificationTimestamp[$uid] = $watchedItem->getNotificationTimestamp();
4472                 } else {
4473                         $this->mNotificationTimestamp[$uid] = false;
4474                 }
4475
4476                 return $this->mNotificationTimestamp[$uid];
4477         }
4478
4479         /**
4480          * Generate strings used for xml 'id' names in monobook tabs
4481          *
4482          * @param string $prepend Defaults to 'nstab-'
4483          * @return string XML 'id' name
4484          */
4485         public function getNamespaceKey( $prepend = 'nstab-' ) {
4486                 global $wgContLang;
4487                 // Gets the subject namespace if this title
4488                 $namespace = MWNamespace::getSubject( $this->getNamespace() );
4489                 // Checks if canonical namespace name exists for namespace
4490                 if ( MWNamespace::exists( $this->getNamespace() ) ) {
4491                         // Uses canonical namespace name
4492                         $namespaceKey = MWNamespace::getCanonicalName( $namespace );
4493                 } else {
4494                         // Uses text of namespace
4495                         $namespaceKey = $this->getSubjectNsText();
4496                 }
4497                 // Makes namespace key lowercase
4498                 $namespaceKey = $wgContLang->lc( $namespaceKey );
4499                 // Uses main
4500                 if ( $namespaceKey == '' ) {
4501                         $namespaceKey = 'main';
4502                 }
4503                 // Changes file to image for backwards compatibility
4504                 if ( $namespaceKey == 'file' ) {
4505                         $namespaceKey = 'image';
4506                 }
4507                 return $prepend . $namespaceKey;
4508         }
4509
4510         /**
4511          * Get all extant redirects to this Title
4512          *
4513          * @param int|null $ns Single namespace to consider; null to consider all namespaces
4514          * @return Title[] Array of Title redirects to this title
4515          */
4516         public function getRedirectsHere( $ns = null ) {
4517                 $redirs = [];
4518
4519                 $dbr = wfGetDB( DB_SLAVE );
4520                 $where = [
4521                         'rd_namespace' => $this->getNamespace(),
4522                         'rd_title' => $this->getDBkey(),
4523                         'rd_from = page_id'
4524                 ];
4525                 if ( $this->isExternal() ) {
4526                         $where['rd_interwiki'] = $this->getInterwiki();
4527                 } else {
4528                         $where[] = 'rd_interwiki = ' . $dbr->addQuotes( '' ) . ' OR rd_interwiki IS NULL';
4529                 }
4530                 if ( !is_null( $ns ) ) {
4531                         $where['page_namespace'] = $ns;
4532                 }
4533
4534                 $res = $dbr->select(
4535                         [ 'redirect', 'page' ],
4536                         [ 'page_namespace', 'page_title' ],
4537                         $where,
4538                         __METHOD__
4539                 );
4540
4541                 foreach ( $res as $row ) {
4542                         $redirs[] = self::newFromRow( $row );
4543                 }
4544                 return $redirs;
4545         }
4546
4547         /**
4548          * Check if this Title is a valid redirect target
4549          *
4550          * @return bool
4551          */
4552         public function isValidRedirectTarget() {
4553                 global $wgInvalidRedirectTargets;
4554
4555                 if ( $this->isSpecialPage() ) {
4556                         // invalid redirect targets are stored in a global array, but explicitly disallow Userlogout here
4557                         if ( $this->isSpecial( 'Userlogout' ) ) {
4558                                 return false;
4559                         }
4560
4561                         foreach ( $wgInvalidRedirectTargets as $target ) {
4562                                 if ( $this->isSpecial( $target ) ) {
4563                                         return false;
4564                                 }
4565                         }
4566                 }
4567
4568                 return true;
4569         }
4570
4571         /**
4572          * Get a backlink cache object
4573          *
4574          * @return BacklinkCache
4575          */
4576         public function getBacklinkCache() {
4577                 return BacklinkCache::get( $this );
4578         }
4579
4580         /**
4581          * Whether the magic words __INDEX__ and __NOINDEX__ function for  this page.
4582          *
4583          * @return bool
4584          */
4585         public function canUseNoindex() {
4586                 global $wgContentNamespaces, $wgExemptFromUserRobotsControl;
4587
4588                 $bannedNamespaces = is_null( $wgExemptFromUserRobotsControl )
4589                         ? $wgContentNamespaces
4590                         : $wgExemptFromUserRobotsControl;
4591
4592                 return !in_array( $this->mNamespace, $bannedNamespaces );
4593
4594         }
4595
4596         /**
4597          * Returns the raw sort key to be used for categories, with the specified
4598          * prefix.  This will be fed to Collation::getSortKey() to get a
4599          * binary sortkey that can be used for actual sorting.
4600          *
4601          * @param string $prefix The prefix to be used, specified using
4602          *   {{defaultsort:}} or like [[Category:Foo|prefix]].  Empty for no
4603          *   prefix.
4604          * @return string
4605          */
4606         public function getCategorySortkey( $prefix = '' ) {
4607                 $unprefixed = $this->getText();
4608
4609                 // Anything that uses this hook should only depend
4610                 // on the Title object passed in, and should probably
4611                 // tell the users to run updateCollations.php --force
4612                 // in order to re-sort existing category relations.
4613                 Hooks::run( 'GetDefaultSortkey', [ $this, &$unprefixed ] );
4614                 if ( $prefix !== '' ) {
4615                         # Separate with a line feed, so the unprefixed part is only used as
4616                         # a tiebreaker when two pages have the exact same prefix.
4617                         # In UCA, tab is the only character that can sort above LF
4618                         # so we strip both of them from the original prefix.
4619                         $prefix = strtr( $prefix, "\n\t", '  ' );
4620                         return "$prefix\n$unprefixed";
4621                 }
4622                 return $unprefixed;
4623         }
4624
4625         /**
4626          * Returns the page language code saved in the database, if $wgPageLanguageUseDB is set
4627          * to true in LocalSettings.php, otherwise returns false. If there is no language saved in
4628          * the db, it will return NULL.
4629          *
4630          * @return string|null|boolean
4631          */
4632         private function getDbPageLanguageCode() {
4633                 global $wgPageLanguageUseDB;
4634
4635                 // check, if the page language could be saved in the database, and if so and
4636                 // the value is not requested already, lookup the page language using LinkCache
4637                 if ( $wgPageLanguageUseDB && $this->mDbPageLanguage === false ) {
4638                         $linkCache = LinkCache::singleton();
4639                         $linkCache->addLinkObj( $this );
4640                         $this->mDbPageLanguage = $linkCache->getGoodLinkFieldObj( $this, 'lang' );
4641                 }
4642
4643                 return $this->mDbPageLanguage;
4644         }
4645
4646         /**
4647          * Get the language in which the content of this page is written in
4648          * wikitext. Defaults to $wgContLang, but in certain cases it can be
4649          * e.g. $wgLang (such as special pages, which are in the user language).
4650          *
4651          * @since 1.18
4652          * @return Language
4653          */
4654         public function getPageLanguage() {
4655                 global $wgLang, $wgLanguageCode;
4656                 if ( $this->isSpecialPage() ) {
4657                         // special pages are in the user language
4658                         return $wgLang;
4659                 }
4660
4661                 // Checking if DB language is set
4662                 $dbPageLanguage = $this->getDbPageLanguageCode();
4663                 if ( $dbPageLanguage ) {
4664                         return wfGetLangObj( $dbPageLanguage );
4665                 }
4666
4667                 if ( !$this->mPageLanguage || $this->mPageLanguage[1] !== $wgLanguageCode ) {
4668                         // Note that this may depend on user settings, so the cache should
4669                         // be only per-request.
4670                         // NOTE: ContentHandler::getPageLanguage() may need to load the
4671                         // content to determine the page language!
4672                         // Checking $wgLanguageCode hasn't changed for the benefit of unit
4673                         // tests.
4674                         $contentHandler = ContentHandler::getForTitle( $this );
4675                         $langObj = $contentHandler->getPageLanguage( $this );
4676                         $this->mPageLanguage = [ $langObj->getCode(), $wgLanguageCode ];
4677                 } else {
4678                         $langObj = wfGetLangObj( $this->mPageLanguage[0] );
4679                 }
4680
4681                 return $langObj;
4682         }
4683
4684         /**
4685          * Get the language in which the content of this page is written when
4686          * viewed by user. Defaults to $wgContLang, but in certain cases it can be
4687          * e.g. $wgLang (such as special pages, which are in the user language).
4688          *
4689          * @since 1.20
4690          * @return Language
4691          */
4692         public function getPageViewLanguage() {
4693                 global $wgLang;
4694
4695                 if ( $this->isSpecialPage() ) {
4696                         // If the user chooses a variant, the content is actually
4697                         // in a language whose code is the variant code.
4698                         $variant = $wgLang->getPreferredVariant();
4699                         if ( $wgLang->getCode() !== $variant ) {
4700                                 return Language::factory( $variant );
4701                         }
4702
4703                         return $wgLang;
4704                 }
4705
4706                 // Checking if DB language is set
4707                 $dbPageLanguage = $this->getDbPageLanguageCode();
4708                 if ( $dbPageLanguage ) {
4709                         $pageLang = wfGetLangObj( $dbPageLanguage );
4710                         $variant = $pageLang->getPreferredVariant();
4711                         if ( $pageLang->getCode() !== $variant ) {
4712                                 $pageLang = Language::factory( $variant );
4713                         }
4714
4715                         return $pageLang;
4716                 }
4717
4718                 // @note Can't be cached persistently, depends on user settings.
4719                 // @note ContentHandler::getPageViewLanguage() may need to load the
4720                 //   content to determine the page language!
4721                 $contentHandler = ContentHandler::getForTitle( $this );
4722                 $pageLang = $contentHandler->getPageViewLanguage( $this );
4723                 return $pageLang;
4724         }
4725
4726         /**
4727          * Get a list of rendered edit notices for this page.
4728          *
4729          * Array is keyed by the original message key, and values are rendered using parseAsBlock, so
4730          * they will already be wrapped in paragraphs.
4731          *
4732          * @since 1.21
4733          * @param int $oldid Revision ID that's being edited
4734          * @return array
4735          */
4736         public function getEditNotices( $oldid = 0 ) {
4737                 $notices = [];
4738
4739                 // Optional notice for the entire namespace
4740                 $editnotice_ns = 'editnotice-' . $this->getNamespace();
4741                 $msg = wfMessage( $editnotice_ns );
4742                 if ( $msg->exists() ) {
4743                         $html = $msg->parseAsBlock();
4744                         // Edit notices may have complex logic, but output nothing (T91715)
4745                         if ( trim( $html ) !== '' ) {
4746                                 $notices[$editnotice_ns] = Html::rawElement(
4747                                         'div',
4748                                         [ 'class' => [
4749                                                 'mw-editnotice',
4750                                                 'mw-editnotice-namespace',
4751                                                 Sanitizer::escapeClass( "mw-$editnotice_ns" )
4752                                         ] ],
4753                                         $html
4754                                 );
4755                         }
4756                 }
4757
4758                 if ( MWNamespace::hasSubpages( $this->getNamespace() ) ) {
4759                         // Optional notice for page itself and any parent page
4760                         $parts = explode( '/', $this->getDBkey() );
4761                         $editnotice_base = $editnotice_ns;
4762                         while ( count( $parts ) > 0 ) {
4763                                 $editnotice_base .= '-' . array_shift( $parts );
4764                                 $msg = wfMessage( $editnotice_base );
4765                                 if ( $msg->exists() ) {
4766                                         $html = $msg->parseAsBlock();
4767                                         if ( trim( $html ) !== '' ) {
4768                                                 $notices[$editnotice_base] = Html::rawElement(
4769                                                         'div',
4770                                                         [ 'class' => [
4771                                                                 'mw-editnotice',
4772                                                                 'mw-editnotice-base',
4773                                                                 Sanitizer::escapeClass( "mw-$editnotice_base" )
4774                                                         ] ],
4775                                                         $html
4776                                                 );
4777                                         }
4778                                 }
4779                         }
4780                 } else {
4781                         // Even if there are no subpages in namespace, we still don't want "/" in MediaWiki message keys
4782                         $editnoticeText = $editnotice_ns . '-' . strtr( $this->getDBkey(), '/', '-' );
4783                         $msg = wfMessage( $editnoticeText );
4784                         if ( $msg->exists() ) {
4785                                 $html = $msg->parseAsBlock();
4786                                 if ( trim( $html ) !== '' ) {
4787                                         $notices[$editnoticeText] = Html::rawElement(
4788                                                 'div',
4789                                                 [ 'class' => [
4790                                                         'mw-editnotice',
4791                                                         'mw-editnotice-page',
4792                                                         Sanitizer::escapeClass( "mw-$editnoticeText" )
4793                                                 ] ],
4794                                                 $html
4795                                         );
4796                                 }
4797                         }
4798                 }
4799
4800                 Hooks::run( 'TitleGetEditNotices', [ $this, $oldid, &$notices ] );
4801                 return $notices;
4802         }
4803
4804         /**
4805          * @return array
4806          */
4807         public function __sleep() {
4808                 return [
4809                         'mNamespace',
4810                         'mDbkeyform',
4811                         'mFragment',
4812                         'mInterwiki',
4813                         'mLocalInterwiki',
4814                         'mUserCaseDBKey',
4815                         'mDefaultNamespace',
4816                 ];
4817         }
4818
4819         public function __wakeup() {
4820                 $this->mArticleID = ( $this->mNamespace >= 0 ) ? -1 : 0;
4821                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
4822                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
4823         }
4824
4825 }