includes/Title.php

   1 <?php
   2 /**
   3  * Representation of a title within %MediaWiki.
   4  *
   5  * See title.txt
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License along
  18  * with this program; if not, write to the Free Software Foundation, Inc.,
  19  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  20  * http://www.gnu.org/copyleft/gpl.html
  21  *
  22  * @file
  23  */
  24 use MediaWiki\Linker\LinkTarget;
  25 use MediaWiki\Interwiki\InterwikiLookup;
  26 use MediaWiki\MediaWikiServices;
  27
  28 /**
  29  * Represents a title within MediaWiki.
  30  * Optionally may contain an interwiki designation or namespace.
  31  * @note This class can fetch various kinds of data from the database;
  32  *       however, it does so inefficiently.
  33  * @note Consider using a TitleValue object instead. TitleValue is more lightweight
  34  *       and does not rely on global state or the database.
  35  */
  36 class Title implements LinkTarget {
  37         /** @var HashBagOStuff */
  38         static private $titleCache = null;
  39
  40         /**
  41          * Title::newFromText maintains a cache to avoid expensive re-normalization of
  42          * commonly used titles. On a batch operation this can become a memory leak
  43          * if not bounded. After hitting this many titles reset the cache.
  44          */
  45         const CACHE_MAX = 1000;
  46
  47         /**
  48          * Used to be GAID_FOR_UPDATE define. Used with getArticleID() and friends
  49          * to use the master DB
  50          */
  51         const GAID_FOR_UPDATE = 1;
  52
  53         /**
  54          * @name Private member variables
  55          * Please use the accessor functions instead.
  56          * @private
  57          */
  58         // @{
  59
  60         /** @var string Text form (spaces not underscores) of the main part */
  61         public $mTextform = '';
  62
  63         /** @var string URL-encoded form of the main part */
  64         public $mUrlform = '';
  65
  66         /** @var string Main part with underscores */
  67         public $mDbkeyform = '';
  68
  69         /** @var string Database key with the initial letter in the case specified by the user */
  70         protected $mUserCaseDBKey;
  71
  72         /** @var int Namespace index, i.e. one of the NS_xxxx constants */
  73         public $mNamespace = NS_MAIN;
  74
  75         /** @var string Interwiki prefix */
  76         public $mInterwiki = '';
  77
  78         /** @var bool Was this Title created from a string with a local interwiki prefix? */
  79         private $mLocalInterwiki = false;
  80
  81         /** @var string Title fragment (i.e. the bit after the #) */
  82         public $mFragment = '';
  83
  84         /** @var int Article ID, fetched from the link cache on demand */
  85         public $mArticleID = -1;
  86
  87         /** @var bool|int ID of most recent revision */
  88         protected $mLatestID = false;
  89
  90         /**
  91          * @var bool|string ID of the page's content model, i.e. one of the
  92          *   CONTENT_MODEL_XXX constants
  93          */
  94         private $mContentModel = false;
  95
  96         /**
  97          * @var bool If a content model was forced via setContentModel()
  98          *   this will be true to avoid having other code paths reset it
  99          */
 100         private $mForcedContentModel = false;
 101
 102         /** @var int Estimated number of revisions; null of not loaded */
 103         private $mEstimateRevisions;
 104
 105         /** @var array Array of groups allowed to edit this article */
 106         public $mRestrictions = [];
 107
 108         /** @var string|bool */
 109         protected $mOldRestrictions = false;
 110
 111         /** @var bool Cascade restrictions on this page to included templates and images? */
 112         public $mCascadeRestriction;
 113
 114         /** Caching the results of getCascadeProtectionSources */
 115         public $mCascadingRestrictions;
 116
 117         /** @var array When do the restrictions on this page expire? */
 118         protected $mRestrictionsExpiry = [];
 119
 120         /** @var bool Are cascading restrictions in effect on this page? */
 121         protected $mHasCascadingRestrictions;
 122
 123         /** @var array Where are the cascading restrictions coming from on this page? */
 124         public $mCascadeSources;
 125
 126         /** @var bool Boolean for initialisation on demand */
 127         public $mRestrictionsLoaded = false;
 128
 129         /** @var string Text form including namespace/interwiki, initialised on demand */
 130         protected $mPrefixedText = null;
 131
 132         /** @var mixed Cached value for getTitleProtection (create protection) */
 133         public $mTitleProtection;
 134
 135         /**
 136          * @var int Namespace index when there is no namespace. Don't change the
 137          *   following default, NS_MAIN is hardcoded in several places. See bug 696.
 138          *   Zero except in {{transclusion}} tags.
 139          */
 140         public $mDefaultNamespace = NS_MAIN;
 141
 142         /** @var int The page length, 0 for special pages */
 143         protected $mLength = -1;
 144
 145         /** @var null Is the article at this title a redirect? */
 146         public $mRedirect = null;
 147
 148         /** @var array Associative array of user ID -> timestamp/false */
 149         private $mNotificationTimestamp = [];
 150
 151         /** @var bool Whether a page has any subpages */
 152         private $mHasSubpages;
 153
 154         /** @var bool The (string) language code of the page's language and content code. */
 155         private $mPageLanguage = false;
 156
 157         /** @var string|bool|null The page language code from the database, null if not saved in
 158          * the database or false if not loaded, yet. */
 159         private $mDbPageLanguage = false;
 160
 161         /** @var TitleValue A corresponding TitleValue object */
 162         private $mTitleValue = null;
 163
 164         /** @var bool Would deleting this page be a big deletion? */
 165         private $mIsBigDeletion = null;
 166         // @}
 167
 168         /**
 169          * B/C kludge: provide a TitleParser for use by Title.
 170          * Ideally, Title would have no methods that need this.
 171          * Avoid usage of this singleton by using TitleValue
 172          * and the associated services when possible.
 173          *
 174          * @return TitleFormatter
 175          */
 176         private static function getTitleFormatter() {
 177                 return MediaWikiServices::getInstance()->getTitleFormatter();
 178         }
 179
 180         /**
 181          * B/C kludge: provide an InterwikiLookup for use by Title.
 182          * Ideally, Title would have no methods that need this.
 183          * Avoid usage of this singleton by using TitleValue
 184          * and the associated services when possible.
 185          *
 186          * @return InterwikiLookup
 187          */
 188         private static function getInterwikiLookup() {
 189                 return MediaWikiServices::getInstance()->getInterwikiLookup();
 190         }
 191
 192         /**
 193          * @access protected
 194          */
 195         function __construct() {
 196         }
 197
 198         /**
 199          * Create a new Title from a prefixed DB key
 200          *
 201          * @param string $key The database key, which has underscores
 202          *      instead of spaces, possibly including namespace and
 203          *      interwiki prefixes
 204          * @return Title|null Title, or null on an error
 205          */
 206         public static function newFromDBkey( $key ) {
 207                 $t = new Title();
 208                 $t->mDbkeyform = $key;
 209
 210                 try {
 211                         $t->secureAndSplit();
 212                         return $t;
 213                 } catch ( MalformedTitleException $ex ) {
 214                         return null;
 215                 }
 216         }
 217
 218         /**
 219          * Create a new Title from a TitleValue
 220          *
 221          * @param TitleValue $titleValue Assumed to be safe.
 222          *
 223          * @return Title
 224          */
 225         public static function newFromTitleValue( TitleValue $titleValue ) {
 226                 return self::newFromLinkTarget( $titleValue );
 227         }
 228
 229         /**
 230          * Create a new Title from a LinkTarget
 231          *
 232          * @param LinkTarget $linkTarget Assumed to be safe.
 233          *
 234          * @return Title
 235          */
 236         public static function newFromLinkTarget( LinkTarget $linkTarget ) {
 237                 if ( $linkTarget instanceof Title ) {
 238                         // Special case if it's already a Title object
 239                         return $linkTarget;
 240                 }
 241                 return self::makeTitle(
 242                         $linkTarget->getNamespace(),
 243                         $linkTarget->getText(),
 244                         $linkTarget->getFragment(),
 245                         $linkTarget->getInterwiki()
 246                 );
 247         }
 248
 249         /**
 250          * Create a new Title from text, such as what one would find in a link. De-
 251          * codes any HTML entities in the text.
 252          *
 253          * @param string|int|null $text The link text; spaces, prefixes, and an
 254          *   initial ':' indicating the main namespace are accepted.
 255          * @param int $defaultNamespace The namespace to use if none is specified
 256          *   by a prefix.  If you want to force a specific namespace even if
 257          *   $text might begin with a namespace prefix, use makeTitle() or
 258          *   makeTitleSafe().
 259          * @throws InvalidArgumentException
 260          * @return Title|null Title or null on an error.
 261          */
 262         public static function newFromText( $text, $defaultNamespace = NS_MAIN ) {
 263                 // DWIM: Integers can be passed in here when page titles are used as array keys.
 264                 if ( $text !== null && !is_string( $text ) && !is_int( $text ) ) {
 265                         throw new InvalidArgumentException( '$text must be a string.' );
 266                 }
 267                 if ( $text === null ) {
 268                         return null;
 269                 }
 270
 271                 try {
 272                         return Title::newFromTextThrow( strval( $text ), $defaultNamespace );
 273                 } catch ( MalformedTitleException $ex ) {
 274                         return null;
 275                 }
 276         }
 277
 278         /**
 279          * Like Title::newFromText(), but throws MalformedTitleException when the title is invalid,
 280          * rather than returning null.
 281          *
 282          * The exception subclasses encode detailed information about why the title is invalid.
 283          *
 284          * @see Title::newFromText
 285          *
 286          * @since 1.25
 287          * @param string $text Title text to check
 288          * @param int $defaultNamespace
 289          * @throws MalformedTitleException If the title is invalid
 290          * @return Title
 291          */
 292         public static function newFromTextThrow( $text, $defaultNamespace = NS_MAIN ) {
 293                 if ( is_object( $text ) ) {
 294                         throw new MWException( '$text must be a string, given an object' );
 295                 }
 296
 297                 $titleCache = self::getTitleCache();
 298
 299                 // Wiki pages often contain multiple links to the same page.
 300                 // Title normalization and parsing can become expensive on pages with many
 301                 // links, so we can save a little time by caching them.
 302                 // In theory these are value objects and won't get changed...
 303                 if ( $defaultNamespace == NS_MAIN ) {
 304                         $t = $titleCache->get( $text );
 305                         if ( $t ) {
 306                                 return $t;
 307                         }
 308                 }
 309
 310                 // Convert things like &eacute; &#257; or &#x3017; into normalized (bug 14952) text
 311                 $filteredText = Sanitizer::decodeCharReferencesAndNormalize( $text );
 312
 313                 $t = new Title();
 314                 $t->mDbkeyform = strtr( $filteredText, ' ', '_' );
 315                 $t->mDefaultNamespace = intval( $defaultNamespace );
 316
 317                 $t->secureAndSplit();
 318                 if ( $defaultNamespace == NS_MAIN ) {
 319                         $titleCache->set( $text, $t );
 320                 }
 321                 return $t;
 322         }
 323
 324         /**
 325          * THIS IS NOT THE FUNCTION YOU WANT. Use Title::newFromText().
 326          *
 327          * Example of wrong and broken code:
 328          * $title = Title::newFromURL( $wgRequest->getVal( 'title' ) );
 329          *
 330          * Example of right code:
 331          * $title = Title::newFromText( $wgRequest->getVal( 'title' ) );
 332          *
 333          * Create a new Title from URL-encoded text. Ensures that
 334          * the given title's length does not exceed the maximum.
 335          *
 336          * @param string $url The title, as might be taken from a URL
 337          * @return Title|null The new object, or null on an error
 338          */
 339         public static function newFromURL( $url ) {
 340                 $t = new Title();
 341
 342                 # For compatibility with old buggy URLs. "+" is usually not valid in titles,
 343                 # but some URLs used it as a space replacement and they still come
 344                 # from some external search tools.
 345                 if ( strpos( self::legalChars(), '+' ) === false ) {
 346                         $url = strtr( $url, '+', ' ' );
 347                 }
 348
 349                 $t->mDbkeyform = strtr( $url, ' ', '_' );
 350
 351                 try {
 352                         $t->secureAndSplit();
 353                         return $t;
 354                 } catch ( MalformedTitleException $ex ) {
 355                         return null;
 356                 }
 357         }
 358
 359         /**
 360          * @return HashBagOStuff
 361          */
 362         private static function getTitleCache() {
 363                 if ( self::$titleCache == null ) {
 364                         self::$titleCache = new HashBagOStuff( [ 'maxKeys' => self::CACHE_MAX ] );
 365                 }
 366                 return self::$titleCache;
 367         }
 368
 369         /**
 370          * Returns a list of fields that are to be selected for initializing Title
 371          * objects or LinkCache entries. Uses $wgContentHandlerUseDB to determine
 372          * whether to include page_content_model.
 373          *
 374          * @return array
 375          */
 376         protected static function getSelectFields() {
 377                 global $wgContentHandlerUseDB, $wgPageLanguageUseDB;
 378
 379                 $fields = [
 380                         'page_namespace', 'page_title', 'page_id',
 381                         'page_len', 'page_is_redirect', 'page_latest',
 382                 ];
 383
 384                 if ( $wgContentHandlerUseDB ) {
 385                         $fields[] = 'page_content_model';
 386                 }
 387
 388                 if ( $wgPageLanguageUseDB ) {
 389                         $fields[] = 'page_lang';
 390                 }
 391
 392                 return $fields;
 393         }
 394
 395         /**
 396          * Create a new Title from an article ID
 397          *
 398          * @param int $id The page_id corresponding to the Title to create
 399          * @param int $flags Use Title::GAID_FOR_UPDATE to use master
 400          * @return Title|null The new object, or null on an error
 401          */
 402         public static function newFromID( $id, $flags = 0 ) {
 403                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_REPLICA );
 404                 $row = $db->selectRow(
 405                         'page',
 406                         self::getSelectFields(),
 407                         [ 'page_id' => $id ],
 408                         __METHOD__
 409                 );
 410                 if ( $row !== false ) {
 411                         $title = Title::newFromRow( $row );
 412                 } else {
 413                         $title = null;
 414                 }
 415                 return $title;
 416         }
 417
 418         /**
 419          * Make an array of titles from an array of IDs
 420          *
 421          * @param int[] $ids Array of IDs
 422          * @return Title[] Array of Titles
 423          */
 424         public static function newFromIDs( $ids ) {
 425                 if ( !count( $ids ) ) {
 426                         return [];
 427                 }
 428                 $dbr = wfGetDB( DB_REPLICA );
 429
 430                 $res = $dbr->select(
 431                         'page',
 432                         self::getSelectFields(),
 433                         [ 'page_id' => $ids ],
 434                         __METHOD__
 435                 );
 436
 437                 $titles = [];
 438                 foreach ( $res as $row ) {
 439                         $titles[] = Title::newFromRow( $row );
 440                 }
 441                 return $titles;
 442         }
 443
 444         /**
 445          * Make a Title object from a DB row
 446          *
 447          * @param stdClass $row Object database row (needs at least page_title,page_namespace)
 448          * @return Title Corresponding Title
 449          */
 450         public static function newFromRow( $row ) {
 451                 $t = self::makeTitle( $row->page_namespace, $row->page_title );
 452                 $t->loadFromRow( $row );
 453                 return $t;
 454         }
 455
 456         /**
 457          * Load Title object fields from a DB row.
 458          * If false is given, the title will be treated as non-existing.
 459          *
 460          * @param stdClass|bool $row Database row
 461          */
 462         public function loadFromRow( $row ) {
 463                 if ( $row ) { // page found
 464                         if ( isset( $row->page_id ) ) {
 465                                 $this->mArticleID = (int)$row->page_id;
 466                         }
 467                         if ( isset( $row->page_len ) ) {
 468                                 $this->mLength = (int)$row->page_len;
 469                         }
 470                         if ( isset( $row->page_is_redirect ) ) {
 471                                 $this->mRedirect = (bool)$row->page_is_redirect;
 472                         }
 473                         if ( isset( $row->page_latest ) ) {
 474                                 $this->mLatestID = (int)$row->page_latest;
 475                         }
 476                         if ( !$this->mForcedContentModel && isset( $row->page_content_model ) ) {
 477                                 $this->mContentModel = strval( $row->page_content_model );
 478                         } elseif ( !$this->mForcedContentModel ) {
 479                                 $this->mContentModel = false; # initialized lazily in getContentModel()
 480                         }
 481                         if ( isset( $row->page_lang ) ) {
 482                                 $this->mDbPageLanguage = (string)$row->page_lang;
 483                         }
 484                         if ( isset( $row->page_restrictions ) ) {
 485                                 $this->mOldRestrictions = $row->page_restrictions;
 486                         }
 487                 } else { // page not found
 488                         $this->mArticleID = 0;
 489                         $this->mLength = 0;
 490                         $this->mRedirect = false;
 491                         $this->mLatestID = 0;
 492                         if ( !$this->mForcedContentModel ) {
 493                                 $this->mContentModel = false; # initialized lazily in getContentModel()
 494                         }
 495                 }
 496         }
 497
 498         /**
 499          * Create a new Title from a namespace index and a DB key.
 500          * It's assumed that $ns and $title are *valid*, for instance when
 501          * they came directly from the database or a special page name.
 502          * For convenience, spaces are converted to underscores so that
 503          * eg user_text fields can be used directly.
 504          *
 505          * @param int $ns The namespace of the article
 506          * @param string $title The unprefixed database key form
 507          * @param string $fragment The link fragment (after the "#")
 508          * @param string $interwiki The interwiki prefix
 509          * @return Title The new object
 510          */
 511         public static function makeTitle( $ns, $title, $fragment = '', $interwiki = '' ) {
 512                 $t = new Title();
 513                 $t->mInterwiki = $interwiki;
 514                 $t->mFragment = $fragment;
 515                 $t->mNamespace = $ns = intval( $ns );
 516                 $t->mDbkeyform = strtr( $title, ' ', '_' );
 517                 $t->mArticleID = ( $ns >= 0 ) ? -1 : 0;
 518                 $t->mUrlform = wfUrlencode( $t->mDbkeyform );
 519                 $t->mTextform = strtr( $title, '_', ' ' );
 520                 $t->mContentModel = false; # initialized lazily in getContentModel()
 521                 return $t;
 522         }
 523
 524         /**
 525          * Create a new Title from a namespace index and a DB key.
 526          * The parameters will be checked for validity, which is a bit slower
 527          * than makeTitle() but safer for user-provided data.
 528          *
 529          * @param int $ns The namespace of the article
 530          * @param string $title Database key form
 531          * @param string $fragment The link fragment (after the "#")
 532          * @param string $interwiki Interwiki prefix
 533          * @return Title|null The new object, or null on an error
 534          */
 535         public static function makeTitleSafe( $ns, $title, $fragment = '', $interwiki = '' ) {
 536                 if ( !MWNamespace::exists( $ns ) ) {
 537                         return null;
 538                 }
 539
 540                 $t = new Title();
 541                 $t->mDbkeyform = Title::makeName( $ns, $title, $fragment, $interwiki, true );
 542
 543                 try {
 544                         $t->secureAndSplit();
 545                         return $t;
 546                 } catch ( MalformedTitleException $ex ) {
 547                         return null;
 548                 }
 549         }
 550
 551         /**
 552          * Create a new Title for the Main Page
 553          *
 554          * @return Title The new object
 555          */
 556         public static function newMainPage() {
 557                 $title = Title::newFromText( wfMessage( 'mainpage' )->inContentLanguage()->text() );
 558                 // Don't give fatal errors if the message is broken
 559                 if ( !$title ) {
 560                         $title = Title::newFromText( 'Main Page' );
 561                 }
 562                 return $title;
 563         }
 564
 565         /**
 566          * Get the prefixed DB key associated with an ID
 567          *
 568          * @param int $id The page_id of the article
 569          * @return Title|null An object representing the article, or null if no such article was found
 570          */
 571         public static function nameOf( $id ) {
 572                 $dbr = wfGetDB( DB_REPLICA );
 573
 574                 $s = $dbr->selectRow(
 575                         'page',
 576                         [ 'page_namespace', 'page_title' ],
 577                         [ 'page_id' => $id ],
 578                         __METHOD__
 579                 );
 580                 if ( $s === false ) {
 581                         return null;
 582                 }
 583
 584                 $n = self::makeName( $s->page_namespace, $s->page_title );
 585                 return $n;
 586         }
 587
 588         /**
 589          * Get a regex character class describing the legal characters in a link
 590          *
 591          * @return string The list of characters, not delimited
 592          */
 593         public static function legalChars() {
 594                 global $wgLegalTitleChars;
 595                 return $wgLegalTitleChars;
 596         }
 597
 598         /**
 599          * Returns a simple regex that will match on characters and sequences invalid in titles.
 600          * Note that this doesn't pick up many things that could be wrong with titles, but that
 601          * replacing this regex with something valid will make many titles valid.
 602          *
 603          * @deprecated since 1.25, use MediaWikiTitleCodec::getTitleInvalidRegex() instead
 604          *
 605          * @return string Regex string
 606          */
 607         static function getTitleInvalidRegex() {
 608                 wfDeprecated( __METHOD__, '1.25' );
 609                 return MediaWikiTitleCodec::getTitleInvalidRegex();
 610         }
 611
 612         /**
 613          * Utility method for converting a character sequence from bytes to Unicode.
 614          *
 615          * Primary usecase being converting $wgLegalTitleChars to a sequence usable in
 616          * javascript, as PHP uses UTF-8 bytes where javascript uses Unicode code units.
 617          *
 618          * @param string $byteClass
 619          * @return string
 620          */
 621         public static function convertByteClassToUnicodeClass( $byteClass ) {
 622                 $length = strlen( $byteClass );
 623                 // Input token queue
 624                 $x0 = $x1 = $x2 = '';
 625                 // Decoded queue
 626                 $d0 = $d1 = $d2 = '';
 627                 // Decoded integer codepoints
 628                 $ord0 = $ord1 = $ord2 = 0;
 629                 // Re-encoded queue
 630                 $r0 = $r1 = $r2 = '';
 631                 // Output
 632                 $out = '';
 633                 // Flags
 634                 $allowUnicode = false;
 635                 for ( $pos = 0; $pos < $length; $pos++ ) {
 636                         // Shift the queues down
 637                         $x2 = $x1;
 638                         $x1 = $x0;
 639                         $d2 = $d1;
 640                         $d1 = $d0;
 641                         $ord2 = $ord1;
 642                         $ord1 = $ord0;
 643                         $r2 = $r1;
 644                         $r1 = $r0;
 645                         // Load the current input token and decoded values
 646                         $inChar = $byteClass[$pos];
 647                         if ( $inChar == '\\' ) {
 648                                 if ( preg_match( '/x([0-9a-fA-F]{2})/A', $byteClass, $m, 0, $pos + 1 ) ) {
 649                                         $x0 = $inChar . $m[0];
 650                                         $d0 = chr( hexdec( $m[1] ) );
 651                                         $pos += strlen( $m[0] );
 652                                 } elseif ( preg_match( '/[0-7]{3}/A', $byteClass, $m, 0, $pos + 1 ) ) {
 653                                         $x0 = $inChar . $m[0];
 654                                         $d0 = chr( octdec( $m[0] ) );
 655                                         $pos += strlen( $m[0] );
 656                                 } elseif ( $pos + 1 >= $length ) {
 657                                         $x0 = $d0 = '\\';
 658                                 } else {
 659                                         $d0 = $byteClass[$pos + 1];
 660                                         $x0 = $inChar . $d0;
 661                                         $pos += 1;
 662                                 }
 663                         } else {
 664                                 $x0 = $d0 = $inChar;
 665                         }
 666                         $ord0 = ord( $d0 );
 667                         // Load the current re-encoded value
 668                         if ( $ord0 < 32 || $ord0 == 0x7f ) {
 669                                 $r0 = sprintf( '\x%02x', $ord0 );
 670                         } elseif ( $ord0 >= 0x80 ) {
 671                                 // Allow unicode if a single high-bit character appears
 672                                 $r0 = sprintf( '\x%02x', $ord0 );
 673                                 $allowUnicode = true;
 674                         } elseif ( strpos( '-\\[]^', $d0 ) !== false ) {
 675                                 $r0 = '\\' . $d0;
 676                         } else {
 677                                 $r0 = $d0;
 678                         }
 679                         // Do the output
 680                         if ( $x0 !== '' && $x1 === '-' && $x2 !== '' ) {
 681                                 // Range
 682                                 if ( $ord2 > $ord0 ) {
 683                                         // Empty range
 684                                 } elseif ( $ord0 >= 0x80 ) {
 685                                         // Unicode range
 686                                         $allowUnicode = true;
 687                                         if ( $ord2 < 0x80 ) {
 688                                                 // Keep the non-unicode section of the range
 689                                                 $out .= "$r2-\\x7F";
 690                                         }
 691                                 } else {
 692                                         // Normal range
 693                                         $out .= "$r2-$r0";
 694                                 }
 695                                 // Reset state to the initial value
 696                                 $x0 = $x1 = $d0 = $d1 = $r0 = $r1 = '';
 697                         } elseif ( $ord2 < 0x80 ) {
 698                                 // ASCII character
 699                                 $out .= $r2;
 700                         }
 701                 }
 702                 if ( $ord1 < 0x80 ) {
 703                         $out .= $r1;
 704                 }
 705                 if ( $ord0 < 0x80 ) {
 706                         $out .= $r0;
 707                 }
 708                 if ( $allowUnicode ) {
 709                         $out .= '\u0080-\uFFFF';
 710                 }
 711                 return $out;
 712         }
 713
 714         /**
 715          * Make a prefixed DB key from a DB key and a namespace index
 716          *
 717          * @param int $ns Numerical representation of the namespace
 718          * @param string $title The DB key form the title
 719          * @param string $fragment The link fragment (after the "#")
 720          * @param string $interwiki The interwiki prefix
 721          * @param bool $canonicalNamespace If true, use the canonical name for
 722          *   $ns instead of the localized version.
 723          * @return string The prefixed form of the title
 724          */
 725         public static function makeName( $ns, $title, $fragment = '', $interwiki = '',
 726                 $canonicalNamespace = false
 727         ) {
 728                 global $wgContLang;
 729
 730                 if ( $canonicalNamespace ) {
 731                         $namespace = MWNamespace::getCanonicalName( $ns );
 732                 } else {
 733                         $namespace = $wgContLang->getNsText( $ns );
 734                 }
 735                 $name = $namespace == '' ? $title : "$namespace:$title";
 736                 if ( strval( $interwiki ) != '' ) {
 737                         $name = "$interwiki:$name";
 738                 }
 739                 if ( strval( $fragment ) != '' ) {
 740                         $name .= '#' . $fragment;
 741                 }
 742                 return $name;
 743         }
 744
 745         /**
 746          * Escape a text fragment, say from a link, for a URL
 747          *
 748          * @param string $fragment Containing a URL or link fragment (after the "#")
 749          * @return string Escaped string
 750          */
 751         static function escapeFragmentForURL( $fragment ) {
 752                 # Note that we don't urlencode the fragment.  urlencoded Unicode
 753                 # fragments appear not to work in IE (at least up to 7) or in at least
 754                 # one version of Opera 9.x.  The W3C validator, for one, doesn't seem
 755                 # to care if they aren't encoded.
 756                 return Sanitizer::escapeId( $fragment, 'noninitial' );
 757         }
 758
 759         /**
 760          * Callback for usort() to do title sorts by (namespace, title)
 761          *
 762          * @param LinkTarget $a
 763          * @param LinkTarget $b
 764          *
 765          * @return int Result of string comparison, or namespace comparison
 766          */
 767         public static function compare( LinkTarget $a, LinkTarget $b ) {
 768                 if ( $a->getNamespace() == $b->getNamespace() ) {
 769                         return strcmp( $a->getText(), $b->getText() );
 770                 } else {
 771                         return $a->getNamespace() - $b->getNamespace();
 772                 }
 773         }
 774
 775         /**
 776          * Determine whether the object refers to a page within
 777          * this project (either this wiki or a wiki with a local
 778          * interwiki, see https://www.mediawiki.org/wiki/Manual:Interwiki_table#iw_local )
 779          *
 780          * @return bool True if this is an in-project interwiki link or a wikilink, false otherwise
 781          */
 782         public function isLocal() {
 783                 if ( $this->isExternal() ) {
 784                         $iw = self::getInterwikiLookup()->fetch( $this->mInterwiki );
 785                         if ( $iw ) {
 786                                 return $iw->isLocal();
 787                         }
 788                 }
 789                 return true;
 790         }
 791
 792         /**
 793          * Is this Title interwiki?
 794          *
 795          * @return bool
 796          */
 797         public function isExternal() {
 798                 return $this->mInterwiki !== '';
 799         }
 800
 801         /**
 802          * Get the interwiki prefix
 803          *
 804          * Use Title::isExternal to check if a interwiki is set
 805          *
 806          * @return string Interwiki prefix
 807          */
 808         public function getInterwiki() {
 809                 return $this->mInterwiki;
 810         }
 811
 812         /**
 813          * Was this a local interwiki link?
 814          *
 815          * @return bool
 816          */
 817         public function wasLocalInterwiki() {
 818                 return $this->mLocalInterwiki;
 819         }
 820
 821         /**
 822          * Determine whether the object refers to a page within
 823          * this project and is transcludable.
 824          *
 825          * @return bool True if this is transcludable
 826          */
 827         public function isTrans() {
 828                 if ( !$this->isExternal() ) {
 829                         return false;
 830                 }
 831
 832                 return self::getInterwikiLookup()->fetch( $this->mInterwiki )->isTranscludable();
 833         }
 834
 835         /**
 836          * Returns the DB name of the distant wiki which owns the object.
 837          *
 838          * @return string The DB name
 839          */
 840         public function getTransWikiID() {
 841                 if ( !$this->isExternal() ) {
 842                         return false;
 843                 }
 844
 845                 return self::getInterwikiLookup()->fetch( $this->mInterwiki )->getWikiID();
 846         }
 847
 848         /**
 849          * Get a TitleValue object representing this Title.
 850          *
 851          * @note Not all valid Titles have a corresponding valid TitleValue
 852          * (e.g. TitleValues cannot represent page-local links that have a
 853          * fragment but no title text).
 854          *
 855          * @return TitleValue|null
 856          */
 857         public function getTitleValue() {
 858                 if ( $this->mTitleValue === null ) {
 859                         try {
 860                                 $this->mTitleValue = new TitleValue(
 861                                         $this->getNamespace(),
 862                                         $this->getDBkey(),
 863                                         $this->getFragment(),
 864                                         $this->getInterwiki()
 865                                 );
 866                         } catch ( InvalidArgumentException $ex ) {
 867                                 wfDebug( __METHOD__ . ': Can\'t create a TitleValue for [[' .
 868                                         $this->getPrefixedText() . ']]: ' . $ex->getMessage() . "\n" );
 869                         }
 870                 }
 871
 872                 return $this->mTitleValue;
 873         }
 874
 875         /**
 876          * Get the text form (spaces not underscores) of the main part
 877          *
 878          * @return string Main part of the title
 879          */
 880         public function getText() {
 881                 return $this->mTextform;
 882         }
 883
 884         /**
 885          * Get the URL-encoded form of the main part
 886          *
 887          * @return string Main part of the title, URL-encoded
 888          */
 889         public function getPartialURL() {
 890                 return $this->mUrlform;
 891         }
 892
 893         /**
 894          * Get the main part with underscores
 895          *
 896          * @return string Main part of the title, with underscores
 897          */
 898         public function getDBkey() {
 899                 return $this->mDbkeyform;
 900         }
 901
 902         /**
 903          * Get the DB key with the initial letter case as specified by the user
 904          *
 905          * @return string DB key
 906          */
 907         function getUserCaseDBKey() {
 908                 if ( !is_null( $this->mUserCaseDBKey ) ) {
 909                         return $this->mUserCaseDBKey;
 910                 } else {
 911                         // If created via makeTitle(), $this->mUserCaseDBKey is not set.
 912                         return $this->mDbkeyform;
 913                 }
 914         }
 915
 916         /**
 917          * Get the namespace index, i.e. one of the NS_xxxx constants.
 918          *
 919          * @return int Namespace index
 920          */
 921         public function getNamespace() {
 922                 return $this->mNamespace;
 923         }
 924
 925         /**
 926          * Get the page's content model id, see the CONTENT_MODEL_XXX constants.
 927          *
 928          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
 929          * @return string Content model id
 930          */
 931         public function getContentModel( $flags = 0 ) {
 932                 if ( !$this->mForcedContentModel
 933                         && ( !$this->mContentModel || $flags === Title::GAID_FOR_UPDATE )
 934                         && $this->getArticleID( $flags )
 935                 ) {
 936                         $linkCache = LinkCache::singleton();
 937                         $linkCache->addLinkObj( $this ); # in case we already had an article ID
 938                         $this->mContentModel = $linkCache->getGoodLinkFieldObj( $this, 'model' );
 939                 }
 940
 941                 if ( !$this->mContentModel ) {
 942                         $this->mContentModel = ContentHandler::getDefaultModelFor( $this );
 943                 }
 944
 945                 return $this->mContentModel;
 946         }
 947
 948         /**
 949          * Convenience method for checking a title's content model name
 950          *
 951          * @param string $id The content model ID (use the CONTENT_MODEL_XXX constants).
 952          * @return bool True if $this->getContentModel() == $id
 953          */
 954         public function hasContentModel( $id ) {
 955                 return $this->getContentModel() == $id;
 956         }
 957
 958         /**
 959          * Set a proposed content model for the page for permissions
 960          * checking. This does not actually change the content model
 961          * of a title!
 962          *
 963          * Additionally, you should make sure you've checked
 964          * ContentHandler::canBeUsedOn() first.
 965          *
 966          * @since 1.28
 967          * @param string $model CONTENT_MODEL_XXX constant
 968          */
 969         public function setContentModel( $model ) {
 970                 $this->mContentModel = $model;
 971                 $this->mForcedContentModel = true;
 972         }
 973
 974         /**
 975          * Get the namespace text
 976          *
 977          * @return string Namespace text
 978          */
 979         public function getNsText() {
 980                 if ( $this->isExternal() ) {
 981                         // This probably shouldn't even happen,
 982                         // but for interwiki transclusion it sometimes does.
 983                         // Use the canonical namespaces if possible to try to
 984                         // resolve a foreign namespace.
 985                         if ( MWNamespace::exists( $this->mNamespace ) ) {
 986                                 return MWNamespace::getCanonicalName( $this->mNamespace );
 987                         }
 988                 }
 989
 990                 try {
 991                         $formatter = self::getTitleFormatter();
 992                         return $formatter->getNamespaceName( $this->mNamespace, $this->mDbkeyform );
 993                 } catch ( InvalidArgumentException $ex ) {
 994                         wfDebug( __METHOD__ . ': ' . $ex->getMessage() . "\n" );
 995                         return false;
 996                 }
 997         }
 998
 999         /**
1000          * Get the namespace text of the subject (rather than talk) page
1001          *
1002          * @return string Namespace text
1003          */
1004         public function getSubjectNsText() {
1005                 global $wgContLang;
1006                 return $wgContLang->getNsText( MWNamespace::getSubject( $this->mNamespace ) );
1007         }
1008
1009         /**
1010          * Get the namespace text of the talk page
1011          *
1012          * @return string Namespace text
1013          */
1014         public function getTalkNsText() {
1015                 global $wgContLang;
1016                 return $wgContLang->getNsText( MWNamespace::getTalk( $this->mNamespace ) );
1017         }
1018
1019         /**
1020          * Could this title have a corresponding talk page?
1021          *
1022          * @return bool
1023          */
1024         public function canTalk() {
1025                 return MWNamespace::canTalk( $this->mNamespace );
1026         }
1027
1028         /**
1029          * Is this in a namespace that allows actual pages?
1030          *
1031          * @return bool
1032          */
1033         public function canExist() {
1034                 return $this->mNamespace >= NS_MAIN;
1035         }
1036
1037         /**
1038          * Can this title be added to a user's watchlist?
1039          *
1040          * @return bool
1041          */
1042         public function isWatchable() {
1043                 return !$this->isExternal() && MWNamespace::isWatchable( $this->getNamespace() );
1044         }
1045
1046         /**
1047          * Returns true if this is a special page.
1048          *
1049          * @return bool
1050          */
1051         public function isSpecialPage() {
1052                 return $this->getNamespace() == NS_SPECIAL;
1053         }
1054
1055         /**
1056          * Returns true if this title resolves to the named special page
1057          *
1058          * @param string $name The special page name
1059          * @return bool
1060          */
1061         public function isSpecial( $name ) {
1062                 if ( $this->isSpecialPage() ) {
1063                         list( $thisName, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $this->getDBkey() );
1064                         if ( $name == $thisName ) {
1065                                 return true;
1066                         }
1067                 }
1068                 return false;
1069         }
1070
1071         /**
1072          * If the Title refers to a special page alias which is not the local default, resolve
1073          * the alias, and localise the name as necessary.  Otherwise, return $this
1074          *
1075          * @return Title
1076          */
1077         public function fixSpecialName() {
1078                 if ( $this->isSpecialPage() ) {
1079                         list( $canonicalName, $par ) = SpecialPageFactory::resolveAlias( $this->mDbkeyform );
1080                         if ( $canonicalName ) {
1081                                 $localName = SpecialPageFactory::getLocalNameFor( $canonicalName, $par );
1082                                 if ( $localName != $this->mDbkeyform ) {
1083                                         return Title::makeTitle( NS_SPECIAL, $localName );
1084                                 }
1085                         }
1086                 }
1087                 return $this;
1088         }
1089
1090         /**
1091          * Returns true if the title is inside the specified namespace.
1092          *
1093          * Please make use of this instead of comparing to getNamespace()
1094          * This function is much more resistant to changes we may make
1095          * to namespaces than code that makes direct comparisons.
1096          * @param int $ns The namespace
1097          * @return bool
1098          * @since 1.19
1099          */
1100         public function inNamespace( $ns ) {
1101                 return MWNamespace::equals( $this->getNamespace(), $ns );
1102         }
1103
1104         /**
1105          * Returns true if the title is inside one of the specified namespaces.
1106          *
1107          * @param int|int[] $namespaces,... The namespaces to check for
1108          * @return bool
1109          * @since 1.19
1110          */
1111         public function inNamespaces( /* ... */ ) {
1112                 $namespaces = func_get_args();
1113                 if ( count( $namespaces ) > 0 && is_array( $namespaces[0] ) ) {
1114                         $namespaces = $namespaces[0];
1115                 }
1116
1117                 foreach ( $namespaces as $ns ) {
1118                         if ( $this->inNamespace( $ns ) ) {
1119                                 return true;
1120                         }
1121                 }
1122
1123                 return false;
1124         }
1125
1126         /**
1127          * Returns true if the title has the same subject namespace as the
1128          * namespace specified.
1129          * For example this method will take NS_USER and return true if namespace
1130          * is either NS_USER or NS_USER_TALK since both of them have NS_USER
1131          * as their subject namespace.
1132          *
1133          * This is MUCH simpler than individually testing for equivalence
1134          * against both NS_USER and NS_USER_TALK, and is also forward compatible.
1135          * @since 1.19
1136          * @param int $ns
1137          * @return bool
1138          */
1139         public function hasSubjectNamespace( $ns ) {
1140                 return MWNamespace::subjectEquals( $this->getNamespace(), $ns );
1141         }
1142
1143         /**
1144          * Is this Title in a namespace which contains content?
1145          * In other words, is this a content page, for the purposes of calculating
1146          * statistics, etc?
1147          *
1148          * @return bool
1149          */
1150         public function isContentPage() {
1151                 return MWNamespace::isContent( $this->getNamespace() );
1152         }
1153
1154         /**
1155          * Would anybody with sufficient privileges be able to move this page?
1156          * Some pages just aren't movable.
1157          *
1158          * @return bool
1159          */
1160         public function isMovable() {
1161                 if ( !MWNamespace::isMovable( $this->getNamespace() ) || $this->isExternal() ) {
1162                         // Interwiki title or immovable namespace. Hooks don't get to override here
1163                         return false;
1164                 }
1165
1166                 $result = true;
1167                 Hooks::run( 'TitleIsMovable', [ $this, &$result ] );
1168                 return $result;
1169         }
1170
1171         /**
1172          * Is this the mainpage?
1173          * @note Title::newFromText seems to be sufficiently optimized by the title
1174          * cache that we don't need to over-optimize by doing direct comparisons and
1175          * accidentally creating new bugs where $title->equals( Title::newFromText() )
1176          * ends up reporting something differently than $title->isMainPage();
1177          *
1178          * @since 1.18
1179          * @return bool
1180          */
1181         public function isMainPage() {
1182                 return $this->equals( Title::newMainPage() );
1183         }
1184
1185         /**
1186          * Is this a subpage?
1187          *
1188          * @return bool
1189          */
1190         public function isSubpage() {
1191                 return MWNamespace::hasSubpages( $this->mNamespace )
1192                         ? strpos( $this->getText(), '/' ) !== false
1193                         : false;
1194         }
1195
1196         /**
1197          * Is this a conversion table for the LanguageConverter?
1198          *
1199          * @return bool
1200          */
1201         public function isConversionTable() {
1202                 // @todo ConversionTable should become a separate content model.
1203
1204                 return $this->getNamespace() == NS_MEDIAWIKI &&
1205                         strpos( $this->getText(), 'Conversiontable/' ) === 0;
1206         }
1207
1208         /**
1209          * Does that page contain wikitext, or it is JS, CSS or whatever?
1210          *
1211          * @return bool
1212          */
1213         public function isWikitextPage() {
1214                 return $this->hasContentModel( CONTENT_MODEL_WIKITEXT );
1215         }
1216
1217         /**
1218          * Could this page contain custom CSS or JavaScript for the global UI.
1219          * This is generally true for pages in the MediaWiki namespace having CONTENT_MODEL_CSS
1220          * or CONTENT_MODEL_JAVASCRIPT.
1221          *
1222          * This method does *not* return true for per-user JS/CSS. Use isCssJsSubpage()
1223          * for that!
1224          *
1225          * Note that this method should not return true for pages that contain and
1226          * show "inactive" CSS or JS.
1227          *
1228          * @return bool
1229          * @todo FIXME: Rename to isSiteConfigPage() and remove deprecated hook
1230          */
1231         public function isCssOrJsPage() {
1232                 $isCssOrJsPage = NS_MEDIAWIKI == $this->mNamespace
1233                         && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1234                                 || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1235
1236                 # @note This hook is also called in ContentHandler::getDefaultModel.
1237                 #   It's called here again to make sure hook functions can force this
1238                 #   method to return true even outside the MediaWiki namespace.
1239
1240                 Hooks::run( 'TitleIsCssOrJsPage', [ $this, &$isCssOrJsPage ], '1.25' );
1241
1242                 return $isCssOrJsPage;
1243         }
1244
1245         /**
1246          * Is this a .css or .js subpage of a user page?
1247          * @return bool
1248          * @todo FIXME: Rename to isUserConfigPage()
1249          */
1250         public function isCssJsSubpage() {
1251                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1252                                 && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1253                                         || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) ) );
1254         }
1255
1256         /**
1257          * Trim down a .css or .js subpage title to get the corresponding skin name
1258          *
1259          * @return string Containing skin name from .css or .js subpage title
1260          */
1261         public function getSkinFromCssJsSubpage() {
1262                 $subpage = explode( '/', $this->mTextform );
1263                 $subpage = $subpage[count( $subpage ) - 1];
1264                 $lastdot = strrpos( $subpage, '.' );
1265                 if ( $lastdot === false ) {
1266                         return $subpage; # Never happens: only called for names ending in '.css' or '.js'
1267                 }
1268                 return substr( $subpage, 0, $lastdot );
1269         }
1270
1271         /**
1272          * Is this a .css subpage of a user page?
1273          *
1274          * @return bool
1275          */
1276         public function isCssSubpage() {
1277                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1278                         && $this->hasContentModel( CONTENT_MODEL_CSS ) );
1279         }
1280
1281         /**
1282          * Is this a .js subpage of a user page?
1283          *
1284          * @return bool
1285          */
1286         public function isJsSubpage() {
1287                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1288                         && $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1289         }
1290
1291         /**
1292          * Is this a talk page of some sort?
1293          *
1294          * @return bool
1295          */
1296         public function isTalkPage() {
1297                 return MWNamespace::isTalk( $this->getNamespace() );
1298         }
1299
1300         /**
1301          * Get a Title object associated with the talk page of this article
1302          *
1303          * @return Title The object for the talk page
1304          */
1305         public function getTalkPage() {
1306                 return Title::makeTitle( MWNamespace::getTalk( $this->getNamespace() ), $this->getDBkey() );
1307         }
1308
1309         /**
1310          * Get a title object associated with the subject page of this
1311          * talk page
1312          *
1313          * @return Title The object for the subject page
1314          */
1315         public function getSubjectPage() {
1316                 // Is this the same title?
1317                 $subjectNS = MWNamespace::getSubject( $this->getNamespace() );
1318                 if ( $this->getNamespace() == $subjectNS ) {
1319                         return $this;
1320                 }
1321                 return Title::makeTitle( $subjectNS, $this->getDBkey() );
1322         }
1323
1324         /**
1325          * Get the other title for this page, if this is a subject page
1326          * get the talk page, if it is a subject page get the talk page
1327          *
1328          * @since 1.25
1329          * @throws MWException
1330          * @return Title
1331          */
1332         public function getOtherPage() {
1333                 if ( $this->isSpecialPage() ) {
1334                         throw new MWException( 'Special pages cannot have other pages' );
1335                 }
1336                 if ( $this->isTalkPage() ) {
1337                         return $this->getSubjectPage();
1338                 } else {
1339                         return $this->getTalkPage();
1340                 }
1341         }
1342
1343         /**
1344          * Get the default namespace index, for when there is no namespace
1345          *
1346          * @return int Default namespace index
1347          */
1348         public function getDefaultNamespace() {
1349                 return $this->mDefaultNamespace;
1350         }
1351
1352         /**
1353          * Get the Title fragment (i.e.\ the bit after the #) in text form
1354          *
1355          * Use Title::hasFragment to check for a fragment
1356          *
1357          * @return string Title fragment
1358          */
1359         public function getFragment() {
1360                 return $this->mFragment;
1361         }
1362
1363         /**
1364          * Check if a Title fragment is set
1365          *
1366          * @return bool
1367          * @since 1.23
1368          */
1369         public function hasFragment() {
1370                 return $this->mFragment !== '';
1371         }
1372
1373         /**
1374          * Get the fragment in URL form, including the "#" character if there is one
1375          * @return string Fragment in URL form
1376          */
1377         public function getFragmentForURL() {
1378                 if ( !$this->hasFragment() ) {
1379                         return '';
1380                 } else {
1381                         return '#' . Title::escapeFragmentForURL( $this->getFragment() );
1382                 }
1383         }
1384
1385         /**
1386          * Set the fragment for this title. Removes the first character from the
1387          * specified fragment before setting, so it assumes you're passing it with
1388          * an initial "#".
1389          *
1390          * Deprecated for public use, use Title::makeTitle() with fragment parameter,
1391          * or Title::createFragmentTarget().
1392          * Still in active use privately.
1393          *
1394          * @private
1395          * @param string $fragment Text
1396          */
1397         public function setFragment( $fragment ) {
1398                 $this->mFragment = strtr( substr( $fragment, 1 ), '_', ' ' );
1399         }
1400
1401         /**
1402          * Creates a new Title for a different fragment of the same page.
1403          *
1404          * @since 1.27
1405          * @param string $fragment
1406          * @return Title
1407          */
1408         public function createFragmentTarget( $fragment ) {
1409                 return self::makeTitle(
1410                         $this->getNamespace(),
1411                         $this->getText(),
1412                         $fragment,
1413                         $this->getInterwiki()
1414                 );
1415
1416         }
1417
1418         /**
1419          * Prefix some arbitrary text with the namespace or interwiki prefix
1420          * of this object
1421          *
1422          * @param string $name The text
1423          * @return string The prefixed text
1424          */
1425         private function prefix( $name ) {
1426                 $p = '';
1427                 if ( $this->isExternal() ) {
1428                         $p = $this->mInterwiki . ':';
1429                 }
1430
1431                 if ( 0 != $this->mNamespace ) {
1432                         $p .= $this->getNsText() . ':';
1433                 }
1434                 return $p . $name;
1435         }
1436
1437         /**
1438          * Get the prefixed database key form
1439          *
1440          * @return string The prefixed title, with underscores and
1441          *  any interwiki and namespace prefixes
1442          */
1443         public function getPrefixedDBkey() {
1444                 $s = $this->prefix( $this->mDbkeyform );
1445                 $s = strtr( $s, ' ', '_' );
1446                 return $s;
1447         }
1448
1449         /**
1450          * Get the prefixed title with spaces.
1451          * This is the form usually used for display
1452          *
1453          * @return string The prefixed title, with spaces
1454          */
1455         public function getPrefixedText() {
1456                 if ( $this->mPrefixedText === null ) {
1457                         $s = $this->prefix( $this->mTextform );
1458                         $s = strtr( $s, '_', ' ' );
1459                         $this->mPrefixedText = $s;
1460                 }
1461                 return $this->mPrefixedText;
1462         }
1463
1464         /**
1465          * Return a string representation of this title
1466          *
1467          * @return string Representation of this title
1468          */
1469         public function __toString() {
1470                 return $this->getPrefixedText();
1471         }
1472
1473         /**
1474          * Get the prefixed title with spaces, plus any fragment
1475          * (part beginning with '#')
1476          *
1477          * @return string The prefixed title, with spaces and the fragment, including '#'
1478          */
1479         public function getFullText() {
1480                 $text = $this->getPrefixedText();
1481                 if ( $this->hasFragment() ) {
1482                         $text .= '#' . $this->getFragment();
1483                 }
1484                 return $text;
1485         }
1486
1487         /**
1488          * Get the root page name text without a namespace, i.e. the leftmost part before any slashes
1489          *
1490          * @par Example:
1491          * @code
1492          * Title::newFromText('User:Foo/Bar/Baz')->getRootText();
1493          * # returns: 'Foo'
1494          * @endcode
1495          *
1496          * @return string Root name
1497          * @since 1.20
1498          */
1499         public function getRootText() {
1500                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1501                         return $this->getText();
1502                 }
1503
1504                 return strtok( $this->getText(), '/' );
1505         }
1506
1507         /**
1508          * Get the root page name title, i.e. the leftmost part before any slashes
1509          *
1510          * @par Example:
1511          * @code
1512          * Title::newFromText('User:Foo/Bar/Baz')->getRootTitle();
1513          * # returns: Title{User:Foo}
1514          * @endcode
1515          *
1516          * @return Title Root title
1517          * @since 1.20
1518          */
1519         public function getRootTitle() {
1520                 return Title::makeTitle( $this->getNamespace(), $this->getRootText() );
1521         }
1522
1523         /**
1524          * Get the base page name without a namespace, i.e. the part before the subpage name
1525          *
1526          * @par Example:
1527          * @code
1528          * Title::newFromText('User:Foo/Bar/Baz')->getBaseText();
1529          * # returns: 'Foo/Bar'
1530          * @endcode
1531          *
1532          * @return string Base name
1533          */
1534         public function getBaseText() {
1535                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1536                         return $this->getText();
1537                 }
1538
1539                 $parts = explode( '/', $this->getText() );
1540                 # Don't discard the real title if there's no subpage involved
1541                 if ( count( $parts ) > 1 ) {
1542                         unset( $parts[count( $parts ) - 1] );
1543                 }
1544                 return implode( '/', $parts );
1545         }
1546
1547         /**
1548          * Get the base page name title, i.e. the part before the subpage name
1549          *
1550          * @par Example:
1551          * @code
1552          * Title::newFromText('User:Foo/Bar/Baz')->getBaseTitle();
1553          * # returns: Title{User:Foo/Bar}
1554          * @endcode
1555          *
1556          * @return Title Base title
1557          * @since 1.20
1558          */
1559         public function getBaseTitle() {
1560                 return Title::makeTitle( $this->getNamespace(), $this->getBaseText() );
1561         }
1562
1563         /**
1564          * Get the lowest-level subpage name, i.e. the rightmost part after any slashes
1565          *
1566          * @par Example:
1567          * @code
1568          * Title::newFromText('User:Foo/Bar/Baz')->getSubpageText();
1569          * # returns: "Baz"
1570          * @endcode
1571          *
1572          * @return string Subpage name
1573          */
1574         public function getSubpageText() {
1575                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1576                         return $this->mTextform;
1577                 }
1578                 $parts = explode( '/', $this->mTextform );
1579                 return $parts[count( $parts ) - 1];
1580         }
1581
1582         /**
1583          * Get the title for a subpage of the current page
1584          *
1585          * @par Example:
1586          * @code
1587          * Title::newFromText('User:Foo/Bar/Baz')->getSubpage("Asdf");
1588          * # returns: Title{User:Foo/Bar/Baz/Asdf}
1589          * @endcode
1590          *
1591          * @param string $text The subpage name to add to the title
1592          * @return Title Subpage title
1593          * @since 1.20
1594          */
1595         public function getSubpage( $text ) {
1596                 return Title::makeTitleSafe( $this->getNamespace(), $this->getText() . '/' . $text );
1597         }
1598
1599         /**
1600          * Get a URL-encoded form of the subpage text
1601          *
1602          * @return string URL-encoded subpage name
1603          */
1604         public function getSubpageUrlForm() {
1605                 $text = $this->getSubpageText();
1606                 $text = wfUrlencode( strtr( $text, ' ', '_' ) );
1607                 return $text;
1608         }
1609
1610         /**
1611          * Get a URL-encoded title (not an actual URL) including interwiki
1612          *
1613          * @return string The URL-encoded form
1614          */
1615         public function getPrefixedURL() {
1616                 $s = $this->prefix( $this->mDbkeyform );
1617                 $s = wfUrlencode( strtr( $s, ' ', '_' ) );
1618                 return $s;
1619         }
1620
1621         /**
1622          * Helper to fix up the get{Canonical,Full,Link,Local,Internal}URL args
1623          * get{Canonical,Full,Link,Local,Internal}URL methods accepted an optional
1624          * second argument named variant. This was deprecated in favor
1625          * of passing an array of option with a "variant" key
1626          * Once $query2 is removed for good, this helper can be dropped
1627          * and the wfArrayToCgi moved to getLocalURL();
1628          *
1629          * @since 1.19 (r105919)
1630          * @param array|string $query
1631          * @param bool $query2
1632          * @return string
1633          */
1634         private static function fixUrlQueryArgs( $query, $query2 = false ) {
1635                 if ( $query2 !== false ) {
1636                         wfDeprecated( "Title::get{Canonical,Full,Link,Local,Internal}URL " .
1637                                 "method called with a second parameter is deprecated. Add your " .
1638                                 "parameter to an array passed as the first parameter.", "1.19" );
1639                 }
1640                 if ( is_array( $query ) ) {
1641                         $query = wfArrayToCgi( $query );
1642                 }
1643                 if ( $query2 ) {
1644                         if ( is_string( $query2 ) ) {
1645                                 // $query2 is a string, we will consider this to be
1646                                 // a deprecated $variant argument and add it to the query
1647                                 $query2 = wfArrayToCgi( [ 'variant' => $query2 ] );
1648                         } else {
1649                                 $query2 = wfArrayToCgi( $query2 );
1650                         }
1651                         // If we have $query content add a & to it first
1652                         if ( $query ) {
1653                                 $query .= '&';
1654                         }
1655                         // Now append the queries together
1656                         $query .= $query2;
1657                 }
1658                 return $query;
1659         }
1660
1661         /**
1662          * Get a real URL referring to this title, with interwiki link and
1663          * fragment
1664          *
1665          * @see self::getLocalURL for the arguments.
1666          * @see wfExpandUrl
1667          * @param array|string $query
1668          * @param bool $query2
1669          * @param string $proto Protocol type to use in URL
1670          * @return string The URL
1671          */
1672         public function getFullURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1673                 $query = self::fixUrlQueryArgs( $query, $query2 );
1674
1675                 # Hand off all the decisions on urls to getLocalURL
1676                 $url = $this->getLocalURL( $query );
1677
1678                 # Expand the url to make it a full url. Note that getLocalURL has the
1679                 # potential to output full urls for a variety of reasons, so we use
1680                 # wfExpandUrl instead of simply prepending $wgServer
1681                 $url = wfExpandUrl( $url, $proto );
1682
1683                 # Finally, add the fragment.
1684                 $url .= $this->getFragmentForURL();
1685
1686                 Hooks::run( 'GetFullURL', [ &$this, &$url, $query ] );
1687                 return $url;
1688         }
1689
1690         /**
1691          * Get a URL with no fragment or server name (relative URL) from a Title object.
1692          * If this page is generated with action=render, however,
1693          * $wgServer is prepended to make an absolute URL.
1694          *
1695          * @see self::getFullURL to always get an absolute URL.
1696          * @see self::getLinkURL to always get a URL that's the simplest URL that will be
1697          *  valid to link, locally, to the current Title.
1698          * @see self::newFromText to produce a Title object.
1699          *
1700          * @param string|array $query An optional query string,
1701          *   not used for interwiki links. Can be specified as an associative array as well,
1702          *   e.g., array( 'action' => 'edit' ) (keys and values will be URL-escaped).
1703          *   Some query patterns will trigger various shorturl path replacements.
1704          * @param array $query2 An optional secondary query array. This one MUST
1705          *   be an array. If a string is passed it will be interpreted as a deprecated
1706          *   variant argument and urlencoded into a variant= argument.
1707          *   This second query argument will be added to the $query
1708          *   The second parameter is deprecated since 1.19. Pass it as a key,value
1709          *   pair in the first parameter array instead.
1710          *
1711          * @return string String of the URL.
1712          */
1713         public function getLocalURL( $query = '', $query2 = false ) {
1714                 global $wgArticlePath, $wgScript, $wgServer, $wgRequest;
1715
1716                 $query = self::fixUrlQueryArgs( $query, $query2 );
1717
1718                 $interwiki = self::getInterwikiLookup()->fetch( $this->mInterwiki );
1719                 if ( $interwiki ) {
1720                         $namespace = $this->getNsText();
1721                         if ( $namespace != '' ) {
1722                                 # Can this actually happen? Interwikis shouldn't be parsed.
1723                                 # Yes! It can in interwiki transclusion. But... it probably shouldn't.
1724                                 $namespace .= ':';
1725                         }
1726                         $url = $interwiki->getURL( $namespace . $this->getDBkey() );
1727                         $url = wfAppendQuery( $url, $query );
1728                 } else {
1729                         $dbkey = wfUrlencode( $this->getPrefixedDBkey() );
1730                         if ( $query == '' ) {
1731                                 $url = str_replace( '$1', $dbkey, $wgArticlePath );
1732                                 Hooks::run( 'GetLocalURL::Article', [ &$this, &$url ] );
1733                         } else {
1734                                 global $wgVariantArticlePath, $wgActionPaths, $wgContLang;
1735                                 $url = false;
1736                                 $matches = [];
1737
1738                                 if ( !empty( $wgActionPaths )
1739                                         && preg_match( '/^(.*&|)action=([^&]*)(&(.*)|)$/', $query, $matches )
1740                                 ) {
1741                                         $action = urldecode( $matches[2] );
1742                                         if ( isset( $wgActionPaths[$action] ) ) {
1743                                                 $query = $matches[1];
1744                                                 if ( isset( $matches[4] ) ) {
1745                                                         $query .= $matches[4];
1746                                                 }
1747                                                 $url = str_replace( '$1', $dbkey, $wgActionPaths[$action] );
1748                                                 if ( $query != '' ) {
1749                                                         $url = wfAppendQuery( $url, $query );
1750                                                 }
1751                                         }
1752                                 }
1753
1754                                 if ( $url === false
1755                                         && $wgVariantArticlePath
1756                                         && preg_match( '/^variant=([^&]*)$/', $query, $matches )
1757                                         && $this->getPageLanguage()->equals( $wgContLang )
1758                                         && $this->getPageLanguage()->hasVariants()
1759                                 ) {
1760                                         $variant = urldecode( $matches[1] );
1761                                         if ( $this->getPageLanguage()->hasVariant( $variant ) ) {
1762                                                 // Only do the variant replacement if the given variant is a valid
1763                                                 // variant for the page's language.
1764                                                 $url = str_replace( '$2', urlencode( $variant ), $wgVariantArticlePath );
1765                                                 $url = str_replace( '$1', $dbkey, $url );
1766                                         }
1767                                 }
1768
1769                                 if ( $url === false ) {
1770                                         if ( $query == '-' ) {
1771                                                 $query = '';
1772                                         }
1773                                         $url = "{$wgScript}?title={$dbkey}&{$query}";
1774                                 }
1775                         }
1776
1777                         Hooks::run( 'GetLocalURL::Internal', [ &$this, &$url, $query ] );
1778
1779                         // @todo FIXME: This causes breakage in various places when we
1780                         // actually expected a local URL and end up with dupe prefixes.
1781                         if ( $wgRequest->getVal( 'action' ) == 'render' ) {
1782                                 $url = $wgServer . $url;
1783                         }
1784                 }
1785                 Hooks::run( 'GetLocalURL', [ &$this, &$url, $query ] );
1786                 return $url;
1787         }
1788
1789         /**
1790          * Get a URL that's the simplest URL that will be valid to link, locally,
1791          * to the current Title.  It includes the fragment, but does not include
1792          * the server unless action=render is used (or the link is external).  If
1793          * there's a fragment but the prefixed text is empty, we just return a link
1794          * to the fragment.
1795          *
1796          * The result obviously should not be URL-escaped, but does need to be
1797          * HTML-escaped if it's being output in HTML.
1798          *
1799          * @param array $query
1800          * @param bool $query2
1801          * @param string|int|bool $proto A PROTO_* constant on how the URL should be expanded,
1802          *                               or false (default) for no expansion
1803          * @see self::getLocalURL for the arguments.
1804          * @return string The URL
1805          */
1806         public function getLinkURL( $query = '', $query2 = false, $proto = false ) {
1807                 if ( $this->isExternal() || $proto !== false ) {
1808                         $ret = $this->getFullURL( $query, $query2, $proto );
1809                 } elseif ( $this->getPrefixedText() === '' && $this->hasFragment() ) {
1810                         $ret = $this->getFragmentForURL();
1811                 } else {
1812                         $ret = $this->getLocalURL( $query, $query2 ) . $this->getFragmentForURL();
1813                 }
1814                 return $ret;
1815         }
1816
1817         /**
1818          * Get the URL form for an internal link.
1819          * - Used in various CDN-related code, in case we have a different
1820          * internal hostname for the server from the exposed one.
1821          *
1822          * This uses $wgInternalServer to qualify the path, or $wgServer
1823          * if $wgInternalServer is not set. If the server variable used is
1824          * protocol-relative, the URL will be expanded to http://
1825          *
1826          * @see self::getLocalURL for the arguments.
1827          * @return string The URL
1828          */
1829         public function getInternalURL( $query = '', $query2 = false ) {
1830                 global $wgInternalServer, $wgServer;
1831                 $query = self::fixUrlQueryArgs( $query, $query2 );
1832                 $server = $wgInternalServer !== false ? $wgInternalServer : $wgServer;
1833                 $url = wfExpandUrl( $server . $this->getLocalURL( $query ), PROTO_HTTP );
1834                 Hooks::run( 'GetInternalURL', [ &$this, &$url, $query ] );
1835                 return $url;
1836         }
1837
1838         /**
1839          * Get the URL for a canonical link, for use in things like IRC and
1840          * e-mail notifications. Uses $wgCanonicalServer and the
1841          * GetCanonicalURL hook.
1842          *
1843          * NOTE: Unlike getInternalURL(), the canonical URL includes the fragment
1844          *
1845          * @see self::getLocalURL for the arguments.
1846          * @return string The URL
1847          * @since 1.18
1848          */
1849         public function getCanonicalURL( $query = '', $query2 = false ) {
1850                 $query = self::fixUrlQueryArgs( $query, $query2 );
1851                 $url = wfExpandUrl( $this->getLocalURL( $query ) . $this->getFragmentForURL(), PROTO_CANONICAL );
1852                 Hooks::run( 'GetCanonicalURL', [ &$this, &$url, $query ] );
1853                 return $url;
1854         }
1855
1856         /**
1857          * Get the edit URL for this Title
1858          *
1859          * @return string The URL, or a null string if this is an interwiki link
1860          */
1861         public function getEditURL() {
1862                 if ( $this->isExternal() ) {
1863                         return '';
1864                 }
1865                 $s = $this->getLocalURL( 'action=edit' );
1866
1867                 return $s;
1868         }
1869
1870         /**
1871          * Can $user perform $action on this page?
1872          * This skips potentially expensive cascading permission checks
1873          * as well as avoids expensive error formatting
1874          *
1875          * Suitable for use for nonessential UI controls in common cases, but
1876          * _not_ for functional access control.
1877          *
1878          * May provide false positives, but should never provide a false negative.
1879          *
1880          * @param string $action Action that permission needs to be checked for
1881          * @param User $user User to check (since 1.19); $wgUser will be used if not provided.
1882          * @return bool
1883          */
1884         public function quickUserCan( $action, $user = null ) {
1885                 return $this->userCan( $action, $user, false );
1886         }
1887
1888         /**
1889          * Can $user perform $action on this page?
1890          *
1891          * @param string $action Action that permission needs to be checked for
1892          * @param User $user User to check (since 1.19); $wgUser will be used if not
1893          *   provided.
1894          * @param string $rigor Same format as Title::getUserPermissionsErrors()
1895          * @return bool
1896          */
1897         public function userCan( $action, $user = null, $rigor = 'secure' ) {
1898                 if ( !$user instanceof User ) {
1899                         global $wgUser;
1900                         $user = $wgUser;
1901                 }
1902
1903                 return !count( $this->getUserPermissionsErrorsInternal( $action, $user, $rigor, true ) );
1904         }
1905
1906         /**
1907          * Can $user perform $action on this page?
1908          *
1909          * @todo FIXME: This *does not* check throttles (User::pingLimiter()).
1910          *
1911          * @param string $action Action that permission needs to be checked for
1912          * @param User $user User to check
1913          * @param string $rigor One of (quick,full,secure)
1914          *   - quick  : does cheap permission checks from replica DBs (usable for GUI creation)
1915          *   - full   : does cheap and expensive checks possibly from a replica DB
1916          *   - secure : does cheap and expensive checks, using the master as needed
1917          * @param array $ignoreErrors Array of Strings Set this to a list of message keys
1918          *   whose corresponding errors may be ignored.
1919          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
1920          */
1921         public function getUserPermissionsErrors(
1922                 $action, $user, $rigor = 'secure', $ignoreErrors = []
1923         ) {
1924                 $errors = $this->getUserPermissionsErrorsInternal( $action, $user, $rigor );
1925
1926                 // Remove the errors being ignored.
1927                 foreach ( $errors as $index => $error ) {
1928                         $errKey = is_array( $error ) ? $error[0] : $error;
1929
1930                         if ( in_array( $errKey, $ignoreErrors ) ) {
1931                                 unset( $errors[$index] );
1932                         }
1933                         if ( $errKey instanceof MessageSpecifier && in_array( $errKey->getKey(), $ignoreErrors ) ) {
1934                                 unset( $errors[$index] );
1935                         }
1936                 }
1937
1938                 return $errors;
1939         }
1940
1941         /**
1942          * Permissions checks that fail most often, and which are easiest to test.
1943          *
1944          * @param string $action The action to check
1945          * @param User $user User to check
1946          * @param array $errors List of current errors
1947          * @param string $rigor Same format as Title::getUserPermissionsErrors()
1948          * @param bool $short Short circuit on first error
1949          *
1950          * @return array List of errors
1951          */
1952         private function checkQuickPermissions( $action, $user, $errors, $rigor, $short ) {
1953                 if ( !Hooks::run( 'TitleQuickPermissions',
1954                         [ $this, $user, $action, &$errors, ( $rigor !== 'quick' ), $short ] )
1955                 ) {
1956                         return $errors;
1957                 }
1958
1959                 if ( $action == 'create' ) {
1960                         if (
1961                                 ( $this->isTalkPage() && !$user->isAllowed( 'createtalk' ) ) ||
1962                                 ( !$this->isTalkPage() && !$user->isAllowed( 'createpage' ) )
1963                         ) {
1964                                 $errors[] = $user->isAnon() ? [ 'nocreatetext' ] : [ 'nocreate-loggedin' ];
1965                         }
1966                 } elseif ( $action == 'move' ) {
1967                         if ( !$user->isAllowed( 'move-rootuserpages' )
1968                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
1969                                 // Show user page-specific message only if the user can move other pages
1970                                 $errors[] = [ 'cant-move-user-page' ];
1971                         }
1972
1973                         // Check if user is allowed to move files if it's a file
1974                         if ( $this->mNamespace == NS_FILE && !$user->isAllowed( 'movefile' ) ) {
1975                                 $errors[] = [ 'movenotallowedfile' ];
1976                         }
1977
1978                         // Check if user is allowed to move category pages if it's a category page
1979                         if ( $this->mNamespace == NS_CATEGORY && !$user->isAllowed( 'move-categorypages' ) ) {
1980                                 $errors[] = [ 'cant-move-category-page' ];
1981                         }
1982
1983                         if ( !$user->isAllowed( 'move' ) ) {
1984                                 // User can't move anything
1985                                 $userCanMove = User::groupHasPermission( 'user', 'move' );
1986                                 $autoconfirmedCanMove = User::groupHasPermission( 'autoconfirmed', 'move' );
1987                                 if ( $user->isAnon() && ( $userCanMove || $autoconfirmedCanMove ) ) {
1988                                         // custom message if logged-in users without any special rights can move
1989                                         $errors[] = [ 'movenologintext' ];
1990                                 } else {
1991                                         $errors[] = [ 'movenotallowed' ];
1992                                 }
1993                         }
1994                 } elseif ( $action == 'move-target' ) {
1995                         if ( !$user->isAllowed( 'move' ) ) {
1996                                 // User can't move anything
1997                                 $errors[] = [ 'movenotallowed' ];
1998                         } elseif ( !$user->isAllowed( 'move-rootuserpages' )
1999                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
2000                                 // Show user page-specific message only if the user can move other pages
2001                                 $errors[] = [ 'cant-move-to-user-page' ];
2002                         } elseif ( !$user->isAllowed( 'move-categorypages' )
2003                                         && $this->mNamespace == NS_CATEGORY ) {
2004                                 // Show category page-specific message only if the user can move other pages
2005                                 $errors[] = [ 'cant-move-to-category-page' ];
2006                         }
2007                 } elseif ( !$user->isAllowed( $action ) ) {
2008                         $errors[] = $this->missingPermissionError( $action, $short );
2009                 }
2010
2011                 return $errors;
2012         }
2013
2014         /**
2015          * Add the resulting error code to the errors array
2016          *
2017          * @param array $errors List of current errors
2018          * @param array $result Result of errors
2019          *
2020          * @return array List of errors
2021          */
2022         private function resultToError( $errors, $result ) {
2023                 if ( is_array( $result ) && count( $result ) && !is_array( $result[0] ) ) {
2024                         // A single array representing an error
2025                         $errors[] = $result;
2026                 } elseif ( is_array( $result ) && is_array( $result[0] ) ) {
2027                         // A nested array representing multiple errors
2028                         $errors = array_merge( $errors, $result );
2029                 } elseif ( $result !== '' && is_string( $result ) ) {
2030                         // A string representing a message-id
2031                         $errors[] = [ $result ];
2032                 } elseif ( $result instanceof MessageSpecifier ) {
2033                         // A message specifier representing an error
2034                         $errors[] = [ $result ];
2035                 } elseif ( $result === false ) {
2036                         // a generic "We don't want them to do that"
2037                         $errors[] = [ 'badaccess-group0' ];
2038                 }
2039                 return $errors;
2040         }
2041
2042         /**
2043          * Check various permission hooks
2044          *
2045          * @param string $action The action to check
2046          * @param User $user User to check
2047          * @param array $errors List of current errors
2048          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2049          * @param bool $short Short circuit on first error
2050          *
2051          * @return array List of errors
2052          */
2053         private function checkPermissionHooks( $action, $user, $errors, $rigor, $short ) {
2054                 // Use getUserPermissionsErrors instead
2055                 $result = '';
2056                 if ( !Hooks::run( 'userCan', [ &$this, &$user, $action, &$result ] ) ) {
2057                         return $result ? [] : [ [ 'badaccess-group0' ] ];
2058                 }
2059                 // Check getUserPermissionsErrors hook
2060                 if ( !Hooks::run( 'getUserPermissionsErrors', [ &$this, &$user, $action, &$result ] ) ) {
2061                         $errors = $this->resultToError( $errors, $result );
2062                 }
2063                 // Check getUserPermissionsErrorsExpensive hook
2064                 if (
2065                         $rigor !== 'quick'
2066                         && !( $short && count( $errors ) > 0 )
2067                         && !Hooks::run( 'getUserPermissionsErrorsExpensive', [ &$this, &$user, $action, &$result ] )
2068                 ) {
2069                         $errors = $this->resultToError( $errors, $result );
2070                 }
2071
2072                 return $errors;
2073         }
2074
2075         /**
2076          * Check permissions on special pages & namespaces
2077          *
2078          * @param string $action The action to check
2079          * @param User $user User to check
2080          * @param array $errors List of current errors
2081          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2082          * @param bool $short Short circuit on first error
2083          *
2084          * @return array List of errors
2085          */
2086         private function checkSpecialsAndNSPermissions( $action, $user, $errors, $rigor, $short ) {
2087                 # Only 'createaccount' can be performed on special pages,
2088                 # which don't actually exist in the DB.
2089                 if ( NS_SPECIAL == $this->mNamespace && $action !== 'createaccount' ) {
2090                         $errors[] = [ 'ns-specialprotected' ];
2091                 }
2092
2093                 # Check $wgNamespaceProtection for restricted namespaces
2094                 if ( $this->isNamespaceProtected( $user ) ) {
2095                         $ns = $this->mNamespace == NS_MAIN ?
2096                                 wfMessage( 'nstab-main' )->text() : $this->getNsText();
2097                         $errors[] = $this->mNamespace == NS_MEDIAWIKI ?
2098                                 [ 'protectedinterface', $action ] : [ 'namespaceprotected', $ns, $action ];
2099                 }
2100
2101                 return $errors;
2102         }
2103
2104         /**
2105          * Check CSS/JS sub-page permissions
2106          *
2107          * @param string $action The action to check
2108          * @param User $user User to check
2109          * @param array $errors List of current errors
2110          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2111          * @param bool $short Short circuit on first error
2112          *
2113          * @return array List of errors
2114          */
2115         private function checkCSSandJSPermissions( $action, $user, $errors, $rigor, $short ) {
2116                 # Protect css/js subpages of user pages
2117                 # XXX: this might be better using restrictions
2118                 # XXX: right 'editusercssjs' is deprecated, for backward compatibility only
2119                 if ( $action != 'patrol' && !$user->isAllowed( 'editusercssjs' ) ) {
2120                         if ( preg_match( '/^' . preg_quote( $user->getName(), '/' ) . '\//', $this->mTextform ) ) {
2121                                 if ( $this->isCssSubpage() && !$user->isAllowedAny( 'editmyusercss', 'editusercss' ) ) {
2122                                         $errors[] = [ 'mycustomcssprotected', $action ];
2123                                 } elseif ( $this->isJsSubpage() && !$user->isAllowedAny( 'editmyuserjs', 'edituserjs' ) ) {
2124                                         $errors[] = [ 'mycustomjsprotected', $action ];
2125                                 }
2126                         } else {
2127                                 if ( $this->isCssSubpage() && !$user->isAllowed( 'editusercss' ) ) {
2128                                         $errors[] = [ 'customcssprotected', $action ];
2129                                 } elseif ( $this->isJsSubpage() && !$user->isAllowed( 'edituserjs' ) ) {
2130                                         $errors[] = [ 'customjsprotected', $action ];
2131                                 }
2132                         }
2133                 }
2134
2135                 return $errors;
2136         }
2137
2138         /**
2139          * Check against page_restrictions table requirements on this
2140          * page. The user must possess all required rights for this
2141          * action.
2142          *
2143          * @param string $action The action to check
2144          * @param User $user User to check
2145          * @param array $errors List of current errors
2146          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2147          * @param bool $short Short circuit on first error
2148          *
2149          * @return array List of errors
2150          */
2151         private function checkPageRestrictions( $action, $user, $errors, $rigor, $short ) {
2152                 foreach ( $this->getRestrictions( $action ) as $right ) {
2153                         // Backwards compatibility, rewrite sysop -> editprotected
2154                         if ( $right == 'sysop' ) {
2155                                 $right = 'editprotected';
2156                         }
2157                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2158                         if ( $right == 'autoconfirmed' ) {
2159                                 $right = 'editsemiprotected';
2160                         }
2161                         if ( $right == '' ) {
2162                                 continue;
2163                         }
2164                         if ( !$user->isAllowed( $right ) ) {
2165                                 $errors[] = [ 'protectedpagetext', $right, $action ];
2166                         } elseif ( $this->mCascadeRestriction && !$user->isAllowed( 'protect' ) ) {
2167                                 $errors[] = [ 'protectedpagetext', 'protect', $action ];
2168                         }
2169                 }
2170
2171                 return $errors;
2172         }
2173
2174         /**
2175          * Check restrictions on cascading pages.
2176          *
2177          * @param string $action The action to check
2178          * @param User $user User to check
2179          * @param array $errors List of current errors
2180          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2181          * @param bool $short Short circuit on first error
2182          *
2183          * @return array List of errors
2184          */
2185         private function checkCascadingSourcesRestrictions( $action, $user, $errors, $rigor, $short ) {
2186                 if ( $rigor !== 'quick' && !$this->isCssJsSubpage() ) {
2187                         # We /could/ use the protection level on the source page, but it's
2188                         # fairly ugly as we have to establish a precedence hierarchy for pages
2189                         # included by multiple cascade-protected pages. So just restrict
2190                         # it to people with 'protect' permission, as they could remove the
2191                         # protection anyway.
2192                         list( $cascadingSources, $restrictions ) = $this->getCascadeProtectionSources();
2193                         # Cascading protection depends on more than this page...
2194                         # Several cascading protected pages may include this page...
2195                         # Check each cascading level
2196                         # This is only for protection restrictions, not for all actions
2197                         if ( isset( $restrictions[$action] ) ) {
2198                                 foreach ( $restrictions[$action] as $right ) {
2199                                         // Backwards compatibility, rewrite sysop -> editprotected
2200                                         if ( $right == 'sysop' ) {
2201                                                 $right = 'editprotected';
2202                                         }
2203                                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2204                                         if ( $right == 'autoconfirmed' ) {
2205                                                 $right = 'editsemiprotected';
2206                                         }
2207                                         if ( $right != '' && !$user->isAllowedAll( 'protect', $right ) ) {
2208                                                 $pages = '';
2209                                                 foreach ( $cascadingSources as $page ) {
2210                                                         $pages .= '* [[:' . $page->getPrefixedText() . "]]\n";
2211                                                 }
2212                                                 $errors[] = [ 'cascadeprotected', count( $cascadingSources ), $pages, $action ];
2213                                         }
2214                                 }
2215                         }
2216                 }
2217
2218                 return $errors;
2219         }
2220
2221         /**
2222          * Check action permissions not already checked in checkQuickPermissions
2223          *
2224          * @param string $action The action to check
2225          * @param User $user User to check
2226          * @param array $errors List of current errors
2227          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2228          * @param bool $short Short circuit on first error
2229          *
2230          * @return array List of errors
2231          */
2232         private function checkActionPermissions( $action, $user, $errors, $rigor, $short ) {
2233                 global $wgDeleteRevisionsLimit, $wgLang;
2234
2235                 if ( $action == 'protect' ) {
2236                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit', $user, $rigor, true ) ) ) {
2237                                 // If they can't edit, they shouldn't protect.
2238                                 $errors[] = [ 'protect-cantedit' ];
2239                         }
2240                 } elseif ( $action == 'create' ) {
2241                         $title_protection = $this->getTitleProtection();
2242                         if ( $title_protection ) {
2243                                 if ( $title_protection['permission'] == ''
2244                                         || !$user->isAllowed( $title_protection['permission'] )
2245                                 ) {
2246                                         $errors[] = [
2247                                                 'titleprotected',
2248                                                 User::whoIs( $title_protection['user'] ),
2249                                                 $title_protection['reason']
2250                                         ];
2251                                 }
2252                         }
2253                 } elseif ( $action == 'move' ) {
2254                         // Check for immobile pages
2255                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2256                                 // Specific message for this case
2257                                 $errors[] = [ 'immobile-source-namespace', $this->getNsText() ];
2258                         } elseif ( !$this->isMovable() ) {
2259                                 // Less specific message for rarer cases
2260                                 $errors[] = [ 'immobile-source-page' ];
2261                         }
2262                 } elseif ( $action == 'move-target' ) {
2263                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2264                                 $errors[] = [ 'immobile-target-namespace', $this->getNsText() ];
2265                         } elseif ( !$this->isMovable() ) {
2266                                 $errors[] = [ 'immobile-target-page' ];
2267                         }
2268                 } elseif ( $action == 'delete' ) {
2269                         $tempErrors = $this->checkPageRestrictions( 'edit', $user, [], $rigor, true );
2270                         if ( !$tempErrors ) {
2271                                 $tempErrors = $this->checkCascadingSourcesRestrictions( 'edit',
2272                                         $user, $tempErrors, $rigor, true );
2273                         }
2274                         if ( $tempErrors ) {
2275                                 // If protection keeps them from editing, they shouldn't be able to delete.
2276                                 $errors[] = [ 'deleteprotected' ];
2277                         }
2278                         if ( $rigor !== 'quick' && $wgDeleteRevisionsLimit
2279                                 && !$this->userCan( 'bigdelete', $user ) && $this->isBigDeletion()
2280                         ) {
2281                                 $errors[] = [ 'delete-toobig', $wgLang->formatNum( $wgDeleteRevisionsLimit ) ];
2282                         }
2283                 }
2284                 return $errors;
2285         }
2286
2287         /**
2288          * Check that the user isn't blocked from editing.
2289          *
2290          * @param string $action The action to check
2291          * @param User $user User to check
2292          * @param array $errors List of current errors
2293          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2294          * @param bool $short Short circuit on first error
2295          *
2296          * @return array List of errors
2297          */
2298         private function checkUserBlock( $action, $user, $errors, $rigor, $short ) {
2299                 global $wgEmailConfirmToEdit, $wgBlockDisablesLogin;
2300                 // Account creation blocks handled at userlogin.
2301                 // Unblocking handled in SpecialUnblock
2302                 if ( $rigor === 'quick' || in_array( $action, [ 'createaccount', 'unblock' ] ) ) {
2303                         return $errors;
2304                 }
2305
2306                 // Optimize for a very common case
2307                 if ( $action === 'read' && !$wgBlockDisablesLogin ) {
2308                         return $errors;
2309                 }
2310
2311                 if ( $wgEmailConfirmToEdit && !$user->isEmailConfirmed() ) {
2312                         $errors[] = [ 'confirmedittext' ];
2313                 }
2314
2315                 $useSlave = ( $rigor !== 'secure' );
2316                 if ( ( $action == 'edit' || $action == 'create' )
2317                         && !$user->isBlockedFrom( $this, $useSlave )
2318                 ) {
2319                         // Don't block the user from editing their own talk page unless they've been
2320                         // explicitly blocked from that too.
2321                 } elseif ( $user->isBlocked() && $user->getBlock()->prevents( $action ) !== false ) {
2322                         // @todo FIXME: Pass the relevant context into this function.
2323                         $errors[] = $user->getBlock()->getPermissionsError( RequestContext::getMain() );
2324                 }
2325
2326                 return $errors;
2327         }
2328
2329         /**
2330          * Check that the user is allowed to read this page.
2331          *
2332          * @param string $action The action to check
2333          * @param User $user User to check
2334          * @param array $errors List of current errors
2335          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2336          * @param bool $short Short circuit on first error
2337          *
2338          * @return array List of errors
2339          */
2340         private function checkReadPermissions( $action, $user, $errors, $rigor, $short ) {
2341                 global $wgWhitelistRead, $wgWhitelistReadRegexp;
2342
2343                 $whitelisted = false;
2344                 if ( User::isEveryoneAllowed( 'read' ) ) {
2345                         # Shortcut for public wikis, allows skipping quite a bit of code
2346                         $whitelisted = true;
2347                 } elseif ( $user->isAllowed( 'read' ) ) {
2348                         # If the user is allowed to read pages, he is allowed to read all pages
2349                         $whitelisted = true;
2350                 } elseif ( $this->isSpecial( 'Userlogin' )
2351                         || $this->isSpecial( 'PasswordReset' )
2352                         || $this->isSpecial( 'Userlogout' )
2353                 ) {
2354                         # Always grant access to the login page.
2355                         # Even anons need to be able to log in.
2356                         $whitelisted = true;
2357                 } elseif ( is_array( $wgWhitelistRead ) && count( $wgWhitelistRead ) ) {
2358                         # Time to check the whitelist
2359                         # Only do these checks is there's something to check against
2360                         $name = $this->getPrefixedText();
2361                         $dbName = $this->getPrefixedDBkey();
2362
2363                         // Check for explicit whitelisting with and without underscores
2364                         if ( in_array( $name, $wgWhitelistRead, true ) || in_array( $dbName, $wgWhitelistRead, true ) ) {
2365                                 $whitelisted = true;
2366                         } elseif ( $this->getNamespace() == NS_MAIN ) {
2367                                 # Old settings might have the title prefixed with
2368                                 # a colon for main-namespace pages
2369                                 if ( in_array( ':' . $name, $wgWhitelistRead ) ) {
2370                                         $whitelisted = true;
2371                                 }
2372                         } elseif ( $this->isSpecialPage() ) {
2373                                 # If it's a special page, ditch the subpage bit and check again
2374                                 $name = $this->getDBkey();
2375                                 list( $name, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $name );
2376                                 if ( $name ) {
2377                                         $pure = SpecialPage::getTitleFor( $name )->getPrefixedText();
2378                                         if ( in_array( $pure, $wgWhitelistRead, true ) ) {
2379                                                 $whitelisted = true;
2380                                         }
2381                                 }
2382                         }
2383                 }
2384
2385                 if ( !$whitelisted && is_array( $wgWhitelistReadRegexp ) && !empty( $wgWhitelistReadRegexp ) ) {
2386                         $name = $this->getPrefixedText();
2387                         // Check for regex whitelisting
2388                         foreach ( $wgWhitelistReadRegexp as $listItem ) {
2389                                 if ( preg_match( $listItem, $name ) ) {
2390                                         $whitelisted = true;
2391                                         break;
2392                                 }
2393                         }
2394                 }
2395
2396                 if ( !$whitelisted ) {
2397                         # If the title is not whitelisted, give extensions a chance to do so...
2398                         Hooks::run( 'TitleReadWhitelist', [ $this, $user, &$whitelisted ] );
2399                         if ( !$whitelisted ) {
2400                                 $errors[] = $this->missingPermissionError( $action, $short );
2401                         }
2402                 }
2403
2404                 return $errors;
2405         }
2406
2407         /**
2408          * Get a description array when the user doesn't have the right to perform
2409          * $action (i.e. when User::isAllowed() returns false)
2410          *
2411          * @param string $action The action to check
2412          * @param bool $short Short circuit on first error
2413          * @return array List of errors
2414          */
2415         private function missingPermissionError( $action, $short ) {
2416                 // We avoid expensive display logic for quickUserCan's and such
2417                 if ( $short ) {
2418                         return [ 'badaccess-group0' ];
2419                 }
2420
2421                 $groups = array_map( [ 'User', 'makeGroupLinkWiki' ],
2422                         User::getGroupsWithPermission( $action ) );
2423
2424                 if ( count( $groups ) ) {
2425                         global $wgLang;
2426                         return [
2427                                 'badaccess-groups',
2428                                 $wgLang->commaList( $groups ),
2429                                 count( $groups )
2430                         ];
2431                 } else {
2432                         return [ 'badaccess-group0' ];
2433                 }
2434         }
2435
2436         /**
2437          * Can $user perform $action on this page? This is an internal function,
2438          * with multiple levels of checks depending on performance needs; see $rigor below.
2439          * It does not check wfReadOnly().
2440          *
2441          * @param string $action Action that permission needs to be checked for
2442          * @param User $user User to check
2443          * @param string $rigor One of (quick,full,secure)
2444          *   - quick  : does cheap permission checks from replica DBs (usable for GUI creation)
2445          *   - full   : does cheap and expensive checks possibly from a replica DB
2446          *   - secure : does cheap and expensive checks, using the master as needed
2447          * @param bool $short Set this to true to stop after the first permission error.
2448          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
2449          */
2450         protected function getUserPermissionsErrorsInternal(
2451                 $action, $user, $rigor = 'secure', $short = false
2452         ) {
2453                 if ( $rigor === true ) {
2454                         $rigor = 'secure'; // b/c
2455                 } elseif ( $rigor === false ) {
2456                         $rigor = 'quick'; // b/c
2457                 } elseif ( !in_array( $rigor, [ 'quick', 'full', 'secure' ] ) ) {
2458                         throw new Exception( "Invalid rigor parameter '$rigor'." );
2459                 }
2460
2461                 # Read has special handling
2462                 if ( $action == 'read' ) {
2463                         $checks = [
2464                                 'checkPermissionHooks',
2465                                 'checkReadPermissions',
2466                                 'checkUserBlock', // for wgBlockDisablesLogin
2467                         ];
2468                 # Don't call checkSpecialsAndNSPermissions or checkCSSandJSPermissions
2469                 # here as it will lead to duplicate error messages. This is okay to do
2470                 # since anywhere that checks for create will also check for edit, and
2471                 # those checks are called for edit.
2472                 } elseif ( $action == 'create' ) {
2473                         $checks = [
2474                                 'checkQuickPermissions',
2475                                 'checkPermissionHooks',
2476                                 'checkPageRestrictions',
2477                                 'checkCascadingSourcesRestrictions',
2478                                 'checkActionPermissions',
2479                                 'checkUserBlock'
2480                         ];
2481                 } else {
2482                         $checks = [
2483                                 'checkQuickPermissions',
2484                                 'checkPermissionHooks',
2485                                 'checkSpecialsAndNSPermissions',
2486                                 'checkCSSandJSPermissions',
2487                                 'checkPageRestrictions',
2488                                 'checkCascadingSourcesRestrictions',
2489                                 'checkActionPermissions',
2490                                 'checkUserBlock'
2491                         ];
2492                 }
2493
2494                 $errors = [];
2495                 while ( count( $checks ) > 0 &&
2496                                 !( $short && count( $errors ) > 0 ) ) {
2497                         $method = array_shift( $checks );
2498                         $errors = $this->$method( $action, $user, $errors, $rigor, $short );
2499                 }
2500
2501                 return $errors;
2502         }
2503
2504         /**
2505          * Get a filtered list of all restriction types supported by this wiki.
2506          * @param bool $exists True to get all restriction types that apply to
2507          * titles that do exist, False for all restriction types that apply to
2508          * titles that do not exist
2509          * @return array
2510          */
2511         public static function getFilteredRestrictionTypes( $exists = true ) {
2512                 global $wgRestrictionTypes;
2513                 $types = $wgRestrictionTypes;
2514                 if ( $exists ) {
2515                         # Remove the create restriction for existing titles
2516                         $types = array_diff( $types, [ 'create' ] );
2517                 } else {
2518                         # Only the create and upload restrictions apply to non-existing titles
2519                         $types = array_intersect( $types, [ 'create', 'upload' ] );
2520                 }
2521                 return $types;
2522         }
2523
2524         /**
2525          * Returns restriction types for the current Title
2526          *
2527          * @return array Applicable restriction types
2528          */
2529         public function getRestrictionTypes() {
2530                 if ( $this->isSpecialPage() ) {
2531                         return [];
2532                 }
2533
2534                 $types = self::getFilteredRestrictionTypes( $this->exists() );
2535
2536                 if ( $this->getNamespace() != NS_FILE ) {
2537                         # Remove the upload restriction for non-file titles
2538                         $types = array_diff( $types, [ 'upload' ] );
2539                 }
2540
2541                 Hooks::run( 'TitleGetRestrictionTypes', [ $this, &$types ] );
2542
2543                 wfDebug( __METHOD__ . ': applicable restrictions to [[' .
2544                         $this->getPrefixedText() . ']] are {' . implode( ',', $types ) . "}\n" );
2545
2546                 return $types;
2547         }
2548
2549         /**
2550          * Is this title subject to title protection?
2551          * Title protection is the one applied against creation of such title.
2552          *
2553          * @return array|bool An associative array representing any existent title
2554          *   protection, or false if there's none.
2555          */
2556         public function getTitleProtection() {
2557                 // Can't protect pages in special namespaces
2558                 if ( $this->getNamespace() < 0 ) {
2559                         return false;
2560                 }
2561
2562                 // Can't protect pages that exist.
2563                 if ( $this->exists() ) {
2564                         return false;
2565                 }
2566
2567                 if ( $this->mTitleProtection === null ) {
2568                         $dbr = wfGetDB( DB_REPLICA );
2569                         $res = $dbr->select(
2570                                 'protected_titles',
2571                                 [
2572                                         'user' => 'pt_user',
2573                                         'reason' => 'pt_reason',
2574                                         'expiry' => 'pt_expiry',
2575                                         'permission' => 'pt_create_perm'
2576                                 ],
2577                                 [ 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ],
2578                                 __METHOD__
2579                         );
2580
2581                         // fetchRow returns false if there are no rows.
2582                         $row = $dbr->fetchRow( $res );
2583                         if ( $row ) {
2584                                 if ( $row['permission'] == 'sysop' ) {
2585                                         $row['permission'] = 'editprotected'; // B/C
2586                                 }
2587                                 if ( $row['permission'] == 'autoconfirmed' ) {
2588                                         $row['permission'] = 'editsemiprotected'; // B/C
2589                                 }
2590                                 $row['expiry'] = $dbr->decodeExpiry( $row['expiry'] );
2591                         }
2592                         $this->mTitleProtection = $row;
2593                 }
2594                 return $this->mTitleProtection;
2595         }
2596
2597         /**
2598          * Remove any title protection due to page existing
2599          */
2600         public function deleteTitleProtection() {
2601                 $dbw = wfGetDB( DB_MASTER );
2602
2603                 $dbw->delete(
2604                         'protected_titles',
2605                         [ 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ],
2606                         __METHOD__
2607                 );
2608                 $this->mTitleProtection = false;
2609         }
2610
2611         /**
2612          * Is this page "semi-protected" - the *only* protection levels are listed
2613          * in $wgSemiprotectedRestrictionLevels?
2614          *
2615          * @param string $action Action to check (default: edit)
2616          * @return bool
2617          */
2618         public function isSemiProtected( $action = 'edit' ) {
2619                 global $wgSemiprotectedRestrictionLevels;
2620
2621                 $restrictions = $this->getRestrictions( $action );
2622                 $semi = $wgSemiprotectedRestrictionLevels;
2623                 if ( !$restrictions || !$semi ) {
2624                         // Not protected, or all protection is full protection
2625                         return false;
2626                 }
2627
2628                 // Remap autoconfirmed to editsemiprotected for BC
2629                 foreach ( array_keys( $semi, 'autoconfirmed' ) as $key ) {
2630                         $semi[$key] = 'editsemiprotected';
2631                 }
2632                 foreach ( array_keys( $restrictions, 'autoconfirmed' ) as $key ) {
2633                         $restrictions[$key] = 'editsemiprotected';
2634                 }
2635
2636                 return !array_diff( $restrictions, $semi );
2637         }
2638
2639         /**
2640          * Does the title correspond to a protected article?
2641          *
2642          * @param string $action The action the page is protected from,
2643          * by default checks all actions.
2644          * @return bool
2645          */
2646         public function isProtected( $action = '' ) {
2647                 global $wgRestrictionLevels;
2648
2649                 $restrictionTypes = $this->getRestrictionTypes();
2650
2651                 # Special pages have inherent protection
2652                 if ( $this->isSpecialPage() ) {
2653                         return true;
2654                 }
2655
2656                 # Check regular protection levels
2657                 foreach ( $restrictionTypes as $type ) {
2658                         if ( $action == $type || $action == '' ) {
2659                                 $r = $this->getRestrictions( $type );
2660                                 foreach ( $wgRestrictionLevels as $level ) {
2661                                         if ( in_array( $level, $r ) && $level != '' ) {
2662                                                 return true;
2663                                         }
2664                                 }
2665                         }
2666                 }
2667
2668                 return false;
2669         }
2670
2671         /**
2672          * Determines if $user is unable to edit this page because it has been protected
2673          * by $wgNamespaceProtection.
2674          *
2675          * @param User $user User object to check permissions
2676          * @return bool
2677          */
2678         public function isNamespaceProtected( User $user ) {
2679                 global $wgNamespaceProtection;
2680
2681                 if ( isset( $wgNamespaceProtection[$this->mNamespace] ) ) {
2682                         foreach ( (array)$wgNamespaceProtection[$this->mNamespace] as $right ) {
2683                                 if ( $right != '' && !$user->isAllowed( $right ) ) {
2684                                         return true;
2685                                 }
2686                         }
2687                 }
2688                 return false;
2689         }
2690
2691         /**
2692          * Cascading protection: Return true if cascading restrictions apply to this page, false if not.
2693          *
2694          * @return bool If the page is subject to cascading restrictions.
2695          */
2696         public function isCascadeProtected() {
2697                 list( $sources, /* $restrictions */ ) = $this->getCascadeProtectionSources( false );
2698                 return ( $sources > 0 );
2699         }
2700
2701         /**
2702          * Determines whether cascading protection sources have already been loaded from
2703          * the database.
2704          *
2705          * @param bool $getPages True to check if the pages are loaded, or false to check
2706          * if the status is loaded.
2707          * @return bool Whether or not the specified information has been loaded
2708          * @since 1.23
2709          */
2710         public function areCascadeProtectionSourcesLoaded( $getPages = true ) {
2711                 return $getPages ? $this->mCascadeSources !== null : $this->mHasCascadingRestrictions !== null;
2712         }
2713
2714         /**
2715          * Cascading protection: Get the source of any cascading restrictions on this page.
2716          *
2717          * @param bool $getPages Whether or not to retrieve the actual pages
2718          *        that the restrictions have come from and the actual restrictions
2719          *        themselves.
2720          * @return array Two elements: First is an array of Title objects of the
2721          *        pages from which cascading restrictions have come, false for
2722          *        none, or true if such restrictions exist but $getPages was not
2723          *        set. Second is an array like that returned by
2724          *        Title::getAllRestrictions(), or an empty array if $getPages is
2725          *        false.
2726          */
2727         public function getCascadeProtectionSources( $getPages = true ) {
2728                 $pagerestrictions = [];
2729
2730                 if ( $this->mCascadeSources !== null && $getPages ) {
2731                         return [ $this->mCascadeSources, $this->mCascadingRestrictions ];
2732                 } elseif ( $this->mHasCascadingRestrictions !== null && !$getPages ) {
2733                         return [ $this->mHasCascadingRestrictions, $pagerestrictions ];
2734                 }
2735
2736                 $dbr = wfGetDB( DB_REPLICA );
2737
2738                 if ( $this->getNamespace() == NS_FILE ) {
2739                         $tables = [ 'imagelinks', 'page_restrictions' ];
2740                         $where_clauses = [
2741                                 'il_to' => $this->getDBkey(),
2742                                 'il_from=pr_page',
2743                                 'pr_cascade' => 1
2744                         ];
2745                 } else {
2746                         $tables = [ 'templatelinks', 'page_restrictions' ];
2747                         $where_clauses = [
2748                                 'tl_namespace' => $this->getNamespace(),
2749                                 'tl_title' => $this->getDBkey(),
2750                                 'tl_from=pr_page',
2751                                 'pr_cascade' => 1
2752                         ];
2753                 }
2754
2755                 if ( $getPages ) {
2756                         $cols = [ 'pr_page', 'page_namespace', 'page_title',
2757                                 'pr_expiry', 'pr_type', 'pr_level' ];
2758                         $where_clauses[] = 'page_id=pr_page';
2759                         $tables[] = 'page';
2760                 } else {
2761                         $cols = [ 'pr_expiry' ];
2762                 }
2763
2764                 $res = $dbr->select( $tables, $cols, $where_clauses, __METHOD__ );
2765
2766                 $sources = $getPages ? [] : false;
2767                 $now = wfTimestampNow();
2768
2769                 foreach ( $res as $row ) {
2770                         $expiry = $dbr->decodeExpiry( $row->pr_expiry );
2771                         if ( $expiry > $now ) {
2772                                 if ( $getPages ) {
2773                                         $page_id = $row->pr_page;
2774                                         $page_ns = $row->page_namespace;
2775                                         $page_title = $row->page_title;
2776                                         $sources[$page_id] = Title::makeTitle( $page_ns, $page_title );
2777                                         # Add groups needed for each restriction type if its not already there
2778                                         # Make sure this restriction type still exists
2779
2780                                         if ( !isset( $pagerestrictions[$row->pr_type] ) ) {
2781                                                 $pagerestrictions[$row->pr_type] = [];
2782                                         }
2783
2784                                         if (
2785                                                 isset( $pagerestrictions[$row->pr_type] )
2786                                                 && !in_array( $row->pr_level, $pagerestrictions[$row->pr_type] )
2787                                         ) {
2788                                                 $pagerestrictions[$row->pr_type][] = $row->pr_level;
2789                                         }
2790                                 } else {
2791                                         $sources = true;
2792                                 }
2793                         }
2794                 }
2795
2796                 if ( $getPages ) {
2797                         $this->mCascadeSources = $sources;
2798                         $this->mCascadingRestrictions = $pagerestrictions;
2799                 } else {
2800                         $this->mHasCascadingRestrictions = $sources;
2801                 }
2802
2803                 return [ $sources, $pagerestrictions ];
2804         }
2805
2806         /**
2807          * Accessor for mRestrictionsLoaded
2808          *
2809          * @return bool Whether or not the page's restrictions have already been
2810          * loaded from the database
2811          * @since 1.23
2812          */
2813         public function areRestrictionsLoaded() {
2814                 return $this->mRestrictionsLoaded;
2815         }
2816
2817         /**
2818          * Accessor/initialisation for mRestrictions
2819          *
2820          * @param string $action Action that permission needs to be checked for
2821          * @return array Restriction levels needed to take the action. All levels are
2822          *     required. Note that restriction levels are normally user rights, but 'sysop'
2823          *     and 'autoconfirmed' are also allowed for backwards compatibility. These should
2824          *     be mapped to 'editprotected' and 'editsemiprotected' respectively.
2825          */
2826         public function getRestrictions( $action ) {
2827                 if ( !$this->mRestrictionsLoaded ) {
2828                         $this->loadRestrictions();
2829                 }
2830                 return isset( $this->mRestrictions[$action] )
2831                                 ? $this->mRestrictions[$action]
2832                                 : [];
2833         }
2834
2835         /**
2836          * Accessor/initialisation for mRestrictions
2837          *
2838          * @return array Keys are actions, values are arrays as returned by
2839          *     Title::getRestrictions()
2840          * @since 1.23
2841          */
2842         public function getAllRestrictions() {
2843                 if ( !$this->mRestrictionsLoaded ) {
2844                         $this->loadRestrictions();
2845                 }
2846                 return $this->mRestrictions;
2847         }
2848
2849         /**
2850          * Get the expiry time for the restriction against a given action
2851          *
2852          * @param string $action
2853          * @return string|bool 14-char timestamp, or 'infinity' if the page is protected forever
2854          *     or not protected at all, or false if the action is not recognised.
2855          */
2856         public function getRestrictionExpiry( $action ) {
2857                 if ( !$this->mRestrictionsLoaded ) {
2858                         $this->loadRestrictions();
2859                 }
2860                 return isset( $this->mRestrictionsExpiry[$action] ) ? $this->mRestrictionsExpiry[$action] : false;
2861         }
2862
2863         /**
2864          * Returns cascading restrictions for the current article
2865          *
2866          * @return bool
2867          */
2868         function areRestrictionsCascading() {
2869                 if ( !$this->mRestrictionsLoaded ) {
2870                         $this->loadRestrictions();
2871                 }
2872
2873                 return $this->mCascadeRestriction;
2874         }
2875
2876         /**
2877          * Compiles list of active page restrictions from both page table (pre 1.10)
2878          * and page_restrictions table for this existing page.
2879          * Public for usage by LiquidThreads.
2880          *
2881          * @param array $rows Array of db result objects
2882          * @param string $oldFashionedRestrictions Comma-separated list of page
2883          *   restrictions from page table (pre 1.10)
2884          */
2885         public function loadRestrictionsFromRows( $rows, $oldFashionedRestrictions = null ) {
2886                 $dbr = wfGetDB( DB_REPLICA );
2887
2888                 $restrictionTypes = $this->getRestrictionTypes();
2889
2890                 foreach ( $restrictionTypes as $type ) {
2891                         $this->mRestrictions[$type] = [];
2892                         $this->mRestrictionsExpiry[$type] = 'infinity';
2893                 }
2894
2895                 $this->mCascadeRestriction = false;
2896
2897                 # Backwards-compatibility: also load the restrictions from the page record (old format).
2898                 if ( $oldFashionedRestrictions !== null ) {
2899                         $this->mOldRestrictions = $oldFashionedRestrictions;
2900                 }
2901
2902                 if ( $this->mOldRestrictions === false ) {
2903                         $this->mOldRestrictions = $dbr->selectField( 'page', 'page_restrictions',
2904                                 [ 'page_id' => $this->getArticleID() ], __METHOD__ );
2905                 }
2906
2907                 if ( $this->mOldRestrictions != '' ) {
2908                         foreach ( explode( ':', trim( $this->mOldRestrictions ) ) as $restrict ) {
2909                                 $temp = explode( '=', trim( $restrict ) );
2910                                 if ( count( $temp ) == 1 ) {
2911                                         // old old format should be treated as edit/move restriction
2912                                         $this->mRestrictions['edit'] = explode( ',', trim( $temp[0] ) );
2913                                         $this->mRestrictions['move'] = explode( ',', trim( $temp[0] ) );
2914                                 } else {
2915                                         $restriction = trim( $temp[1] );
2916                                         if ( $restriction != '' ) { // some old entries are empty
2917                                                 $this->mRestrictions[$temp[0]] = explode( ',', $restriction );
2918                                         }
2919                                 }
2920                         }
2921                 }
2922
2923                 if ( count( $rows ) ) {
2924                         # Current system - load second to make them override.
2925                         $now = wfTimestampNow();
2926
2927                         # Cycle through all the restrictions.
2928                         foreach ( $rows as $row ) {
2929
2930                                 // Don't take care of restrictions types that aren't allowed
2931                                 if ( !in_array( $row->pr_type, $restrictionTypes ) ) {
2932                                         continue;
2933                                 }
2934
2935                                 // This code should be refactored, now that it's being used more generally,
2936                                 // But I don't really see any harm in leaving it in Block for now -werdna
2937                                 $expiry = $dbr->decodeExpiry( $row->pr_expiry );
2938
2939                                 // Only apply the restrictions if they haven't expired!
2940                                 if ( !$expiry || $expiry > $now ) {
2941                                         $this->mRestrictionsExpiry[$row->pr_type] = $expiry;
2942                                         $this->mRestrictions[$row->pr_type] = explode( ',', trim( $row->pr_level ) );
2943
2944                                         $this->mCascadeRestriction |= $row->pr_cascade;
2945                                 }
2946                         }
2947                 }
2948
2949                 $this->mRestrictionsLoaded = true;
2950         }
2951
2952         /**
2953          * Load restrictions from the page_restrictions table
2954          *
2955          * @param string $oldFashionedRestrictions Comma-separated list of page
2956          *   restrictions from page table (pre 1.10)
2957          */
2958         public function loadRestrictions( $oldFashionedRestrictions = null ) {
2959                 if ( $this->mRestrictionsLoaded ) {
2960                         return;
2961                 }
2962
2963                 $id = $this->getArticleID();
2964                 if ( $id ) {
2965                         $cache = ObjectCache::getMainWANInstance();
2966                         $rows = $cache->getWithSetCallback(
2967                                 // Page protections always leave a new null revision
2968                                 $cache->makeKey( 'page-restrictions', $id, $this->getLatestRevID() ),
2969                                 $cache::TTL_DAY,
2970                                 function ( $curValue, &$ttl, array &$setOpts ) {
2971                                         $dbr = wfGetDB( DB_REPLICA );
2972
2973                                         $setOpts += Database::getCacheSetOptions( $dbr );
2974
2975                                         return iterator_to_array(
2976                                                 $dbr->select(
2977                                                         'page_restrictions',
2978                                                         [ 'pr_type', 'pr_expiry', 'pr_level', 'pr_cascade' ],
2979                                                         [ 'pr_page' => $this->getArticleID() ],
2980                                                         __METHOD__
2981                                                 )
2982                                         );
2983                                 }
2984                         );
2985
2986                         $this->loadRestrictionsFromRows( $rows, $oldFashionedRestrictions );
2987                 } else {
2988                         $title_protection = $this->getTitleProtection();
2989
2990                         if ( $title_protection ) {
2991                                 $now = wfTimestampNow();
2992                                 $expiry = wfGetDB( DB_REPLICA )->decodeExpiry( $title_protection['expiry'] );
2993
2994                                 if ( !$expiry || $expiry > $now ) {
2995                                         // Apply the restrictions
2996                                         $this->mRestrictionsExpiry['create'] = $expiry;
2997                                         $this->mRestrictions['create'] =
2998                                                 explode( ',', trim( $title_protection['permission'] ) );
2999                                 } else { // Get rid of the old restrictions
3000                                         $this->mTitleProtection = false;
3001                                 }
3002                         } else {
3003                                 $this->mRestrictionsExpiry['create'] = 'infinity';
3004                         }
3005                         $this->mRestrictionsLoaded = true;
3006                 }
3007         }
3008
3009         /**
3010          * Flush the protection cache in this object and force reload from the database.
3011          * This is used when updating protection from WikiPage::doUpdateRestrictions().
3012          */
3013         public function flushRestrictions() {
3014                 $this->mRestrictionsLoaded = false;
3015                 $this->mTitleProtection = null;
3016         }
3017
3018         /**
3019          * Purge expired restrictions from the page_restrictions table
3020          *
3021          * This will purge no more than $wgUpdateRowsPerQuery page_restrictions rows
3022          */
3023         static function purgeExpiredRestrictions() {
3024                 if ( wfReadOnly() ) {
3025                         return;
3026                 }
3027
3028                 DeferredUpdates::addUpdate( new AtomicSectionUpdate(
3029                         wfGetDB( DB_MASTER ),
3030                         __METHOD__,
3031                         function ( IDatabase $dbw, $fname ) {
3032                                 $config = MediaWikiServices::getInstance()->getMainConfig();
3033                                 $ids = $dbw->selectFieldValues(
3034                                         'page_restrictions',
3035                                         'pr_id',
3036                                         [ 'pr_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ],
3037                                         $fname,
3038                                         [ 'LIMIT' => $config->get( 'UpdateRowsPerQuery' ) ] // T135470
3039                                 );
3040                                 if ( $ids ) {
3041                                         $dbw->delete( 'page_restrictions', [ 'pr_id' => $ids ], $fname );
3042                                 }
3043                         }
3044                 ) );
3045
3046                 DeferredUpdates::addUpdate( new AtomicSectionUpdate(
3047                         wfGetDB( DB_MASTER ),
3048                         __METHOD__,
3049                         function ( IDatabase $dbw, $fname ) {
3050                                 $dbw->delete(
3051                                         'protected_titles',
3052                                         [ 'pt_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ],
3053                                         $fname
3054                                 );
3055                         }
3056                 ) );
3057         }
3058
3059         /**
3060          * Does this have subpages?  (Warning, usually requires an extra DB query.)
3061          *
3062          * @return bool
3063          */
3064         public function hasSubpages() {
3065                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
3066                         # Duh
3067                         return false;
3068                 }
3069
3070                 # We dynamically add a member variable for the purpose of this method
3071                 # alone to cache the result.  There's no point in having it hanging
3072                 # around uninitialized in every Title object; therefore we only add it
3073                 # if needed and don't declare it statically.
3074                 if ( $this->mHasSubpages === null ) {
3075                         $this->mHasSubpages = false;
3076                         $subpages = $this->getSubpages( 1 );
3077                         if ( $subpages instanceof TitleArray ) {
3078                                 $this->mHasSubpages = (bool)$subpages->count();
3079                         }
3080                 }
3081
3082                 return $this->mHasSubpages;
3083         }
3084
3085         /**
3086          * Get all subpages of this page.
3087          *
3088          * @param int $limit Maximum number of subpages to fetch; -1 for no limit
3089          * @return TitleArray|array TitleArray, or empty array if this page's namespace
3090          *  doesn't allow subpages
3091          */
3092         public function getSubpages( $limit = -1 ) {
3093                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3094                         return [];
3095                 }
3096
3097                 $dbr = wfGetDB( DB_REPLICA );
3098                 $conds['page_namespace'] = $this->getNamespace();
3099                 $conds[] = 'page_title ' . $dbr->buildLike( $this->getDBkey() . '/', $dbr->anyString() );
3100                 $options = [];
3101                 if ( $limit > -1 ) {
3102                         $options['LIMIT'] = $limit;
3103                 }
3104                 $this->mSubpages = TitleArray::newFromResult(
3105                         $dbr->select( 'page',
3106                                 [ 'page_id', 'page_namespace', 'page_title', 'page_is_redirect' ],
3107                                 $conds,
3108                                 __METHOD__,
3109                                 $options
3110                         )
3111                 );
3112                 return $this->mSubpages;
3113         }
3114
3115         /**
3116          * Is there a version of this page in the deletion archive?
3117          *
3118          * @return int The number of archived revisions
3119          */
3120         public function isDeleted() {
3121                 if ( $this->getNamespace() < 0 ) {
3122                         $n = 0;
3123                 } else {
3124                         $dbr = wfGetDB( DB_REPLICA );
3125
3126                         $n = $dbr->selectField( 'archive', 'COUNT(*)',
3127                                 [ 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ],
3128                                 __METHOD__
3129                         );
3130                         if ( $this->getNamespace() == NS_FILE ) {
3131                                 $n += $dbr->selectField( 'filearchive', 'COUNT(*)',
3132                                         [ 'fa_name' => $this->getDBkey() ],
3133                                         __METHOD__
3134                                 );
3135                         }
3136                 }
3137                 return (int)$n;
3138         }
3139
3140         /**
3141          * Is there a version of this page in the deletion archive?
3142          *
3143          * @return bool
3144          */
3145         public function isDeletedQuick() {
3146                 if ( $this->getNamespace() < 0 ) {
3147                         return false;
3148                 }
3149                 $dbr = wfGetDB( DB_REPLICA );
3150                 $deleted = (bool)$dbr->selectField( 'archive', '1',
3151                         [ 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ],
3152                         __METHOD__
3153                 );
3154                 if ( !$deleted && $this->getNamespace() == NS_FILE ) {
3155                         $deleted = (bool)$dbr->selectField( 'filearchive', '1',
3156                                 [ 'fa_name' => $this->getDBkey() ],
3157                                 __METHOD__
3158                         );
3159                 }
3160                 return $deleted;
3161         }
3162
3163         /**
3164          * Get the article ID for this Title from the link cache,
3165          * adding it if necessary
3166          *
3167          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select
3168          *  for update
3169          * @return int The ID
3170          */
3171         public function getArticleID( $flags = 0 ) {
3172                 if ( $this->getNamespace() < 0 ) {
3173                         $this->mArticleID = 0;
3174                         return $this->mArticleID;
3175                 }
3176                 $linkCache = LinkCache::singleton();
3177                 if ( $flags & self::GAID_FOR_UPDATE ) {
3178                         $oldUpdate = $linkCache->forUpdate( true );
3179                         $linkCache->clearLink( $this );
3180                         $this->mArticleID = $linkCache->addLinkObj( $this );
3181                         $linkCache->forUpdate( $oldUpdate );
3182                 } else {
3183                         if ( -1 == $this->mArticleID ) {
3184                                 $this->mArticleID = $linkCache->addLinkObj( $this );
3185                         }
3186                 }
3187                 return $this->mArticleID;
3188         }
3189
3190         /**
3191          * Is this an article that is a redirect page?
3192          * Uses link cache, adding it if necessary
3193          *
3194          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3195          * @return bool
3196          */
3197         public function isRedirect( $flags = 0 ) {
3198                 if ( !is_null( $this->mRedirect ) ) {
3199                         return $this->mRedirect;
3200                 }
3201                 if ( !$this->getArticleID( $flags ) ) {
3202                         $this->mRedirect = false;
3203                         return $this->mRedirect;
3204                 }
3205
3206                 $linkCache = LinkCache::singleton();
3207                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3208                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'redirect' );
3209                 if ( $cached === null ) {
3210                         # Trust LinkCache's state over our own
3211                         # LinkCache is telling us that the page doesn't exist, despite there being cached
3212                         # data relating to an existing page in $this->mArticleID. Updaters should clear
3213                         # LinkCache as appropriate, or use $flags = Title::GAID_FOR_UPDATE. If that flag is
3214                         # set, then LinkCache will definitely be up to date here, since getArticleID() forces
3215                         # LinkCache to refresh its data from the master.
3216                         $this->mRedirect = false;
3217                         return $this->mRedirect;
3218                 }
3219
3220                 $this->mRedirect = (bool)$cached;
3221
3222                 return $this->mRedirect;
3223         }
3224
3225         /**
3226          * What is the length of this page?
3227          * Uses link cache, adding it if necessary
3228          *
3229          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3230          * @return int
3231          */
3232         public function getLength( $flags = 0 ) {
3233                 if ( $this->mLength != -1 ) {
3234                         return $this->mLength;
3235                 }
3236                 if ( !$this->getArticleID( $flags ) ) {
3237                         $this->mLength = 0;
3238                         return $this->mLength;
3239                 }
3240                 $linkCache = LinkCache::singleton();
3241                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3242                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'length' );
3243                 if ( $cached === null ) {
3244                         # Trust LinkCache's state over our own, as for isRedirect()
3245                         $this->mLength = 0;
3246                         return $this->mLength;
3247                 }
3248
3249                 $this->mLength = intval( $cached );
3250
3251                 return $this->mLength;
3252         }
3253
3254         /**
3255          * What is the page_latest field for this page?
3256          *
3257          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3258          * @return int Int or 0 if the page doesn't exist
3259          */
3260         public function getLatestRevID( $flags = 0 ) {
3261                 if ( !( $flags & Title::GAID_FOR_UPDATE ) && $this->mLatestID !== false ) {
3262                         return intval( $this->mLatestID );
3263                 }
3264                 if ( !$this->getArticleID( $flags ) ) {
3265                         $this->mLatestID = 0;
3266                         return $this->mLatestID;
3267                 }
3268                 $linkCache = LinkCache::singleton();
3269                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3270                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'revision' );
3271                 if ( $cached === null ) {
3272                         # Trust LinkCache's state over our own, as for isRedirect()
3273                         $this->mLatestID = 0;
3274                         return $this->mLatestID;
3275                 }
3276
3277                 $this->mLatestID = intval( $cached );
3278
3279                 return $this->mLatestID;
3280         }
3281
3282         /**
3283          * This clears some fields in this object, and clears any associated
3284          * keys in the "bad links" section of the link cache.
3285          *
3286          * - This is called from WikiPage::doEditContent() and WikiPage::insertOn() to allow
3287          * loading of the new page_id. It's also called from
3288          * WikiPage::doDeleteArticleReal()
3289          *
3290          * @param int $newid The new Article ID
3291          */
3292         public function resetArticleID( $newid ) {
3293                 $linkCache = LinkCache::singleton();
3294                 $linkCache->clearLink( $this );
3295
3296                 if ( $newid === false ) {
3297                         $this->mArticleID = -1;
3298                 } else {
3299                         $this->mArticleID = intval( $newid );
3300                 }
3301                 $this->mRestrictionsLoaded = false;
3302                 $this->mRestrictions = [];
3303                 $this->mOldRestrictions = false;
3304                 $this->mRedirect = null;
3305                 $this->mLength = -1;
3306                 $this->mLatestID = false;
3307                 $this->mContentModel = false;
3308                 $this->mEstimateRevisions = null;
3309                 $this->mPageLanguage = false;
3310                 $this->mDbPageLanguage = false;
3311                 $this->mIsBigDeletion = null;
3312         }
3313
3314         public static function clearCaches() {
3315                 $linkCache = LinkCache::singleton();
3316                 $linkCache->clear();
3317
3318                 $titleCache = self::getTitleCache();
3319                 $titleCache->clear();
3320         }
3321
3322         /**
3323          * Capitalize a text string for a title if it belongs to a namespace that capitalizes
3324          *
3325          * @param string $text Containing title to capitalize
3326          * @param int $ns Namespace index, defaults to NS_MAIN
3327          * @return string Containing capitalized title
3328          */
3329         public static function capitalize( $text, $ns = NS_MAIN ) {
3330                 global $wgContLang;
3331
3332                 if ( MWNamespace::isCapitalized( $ns ) ) {
3333                         return $wgContLang->ucfirst( $text );
3334                 } else {
3335                         return $text;
3336                 }
3337         }
3338
3339         /**
3340          * Secure and split - main initialisation function for this object
3341          *
3342          * Assumes that mDbkeyform has been set, and is urldecoded
3343          * and uses underscores, but not otherwise munged.  This function
3344          * removes illegal characters, splits off the interwiki and
3345          * namespace prefixes, sets the other forms, and canonicalizes
3346          * everything.
3347          *
3348          * @throws MalformedTitleException On invalid titles
3349          * @return bool True on success
3350          */
3351         private function secureAndSplit() {
3352                 # Initialisation
3353                 $this->mInterwiki = '';
3354                 $this->mFragment = '';
3355                 $this->mNamespace = $this->mDefaultNamespace; # Usually NS_MAIN
3356
3357                 $dbkey = $this->mDbkeyform;
3358
3359                 // @note: splitTitleString() is a temporary hack to allow MediaWikiTitleCodec to share
3360                 //        the parsing code with Title, while avoiding massive refactoring.
3361                 // @todo: get rid of secureAndSplit, refactor parsing code.
3362                 // @note: getTitleParser() returns a TitleParser implementation which does not have a
3363                 //        splitTitleString method, but the only implementation (MediaWikiTitleCodec) does
3364                 $titleCodec = MediaWikiServices::getInstance()->getTitleParser();
3365                 // MalformedTitleException can be thrown here
3366                 $parts = $titleCodec->splitTitleString( $dbkey, $this->getDefaultNamespace() );
3367
3368                 # Fill fields
3369                 $this->setFragment( '#' . $parts['fragment'] );
3370                 $this->mInterwiki = $parts['interwiki'];
3371                 $this->mLocalInterwiki = $parts['local_interwiki'];
3372                 $this->mNamespace = $parts['namespace'];
3373                 $this->mUserCaseDBKey = $parts['user_case_dbkey'];
3374
3375                 $this->mDbkeyform = $parts['dbkey'];
3376                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
3377                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
3378
3379                 # We already know that some pages won't be in the database!
3380                 if ( $this->isExternal() || $this->mNamespace == NS_SPECIAL ) {
3381                         $this->mArticleID = 0;
3382                 }
3383
3384                 return true;
3385         }
3386
3387         /**
3388          * Get an array of Title objects linking to this Title
3389          * Also stores the IDs in the link cache.
3390          *
3391          * WARNING: do not use this function on arbitrary user-supplied titles!
3392          * On heavily-used templates it will max out the memory.
3393          *
3394          * @param array $options May be FOR UPDATE
3395          * @param string $table Table name
3396          * @param string $prefix Fields prefix
3397          * @return Title[] Array of Title objects linking here
3398          */
3399         public function getLinksTo( $options = [], $table = 'pagelinks', $prefix = 'pl' ) {
3400                 if ( count( $options ) > 0 ) {
3401                         $db = wfGetDB( DB_MASTER );
3402                 } else {
3403                         $db = wfGetDB( DB_REPLICA );
3404                 }
3405
3406                 $res = $db->select(
3407                         [ 'page', $table ],
3408                         self::getSelectFields(),
3409                         [
3410                                 "{$prefix}_from=page_id",
3411                                 "{$prefix}_namespace" => $this->getNamespace(),
3412                                 "{$prefix}_title" => $this->getDBkey() ],
3413                         __METHOD__,
3414                         $options
3415                 );
3416
3417                 $retVal = [];
3418                 if ( $res->numRows() ) {
3419                         $linkCache = LinkCache::singleton();
3420                         foreach ( $res as $row ) {
3421                                 $titleObj = Title::makeTitle( $row->page_namespace, $row->page_title );
3422                                 if ( $titleObj ) {
3423                                         $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3424                                         $retVal[] = $titleObj;
3425                                 }
3426                         }
3427                 }
3428                 return $retVal;
3429         }
3430
3431         /**
3432          * Get an array of Title objects using this Title as a template
3433          * Also stores the IDs in the link cache.
3434          *
3435          * WARNING: do not use this function on arbitrary user-supplied titles!
3436          * On heavily-used templates it will max out the memory.
3437          *
3438          * @param array $options Query option to Database::select()
3439          * @return Title[] Array of Title the Title objects linking here
3440          */
3441         public function getTemplateLinksTo( $options = [] ) {
3442                 return $this->getLinksTo( $options, 'templatelinks', 'tl' );
3443         }
3444
3445         /**
3446          * Get an array of Title objects linked from this Title
3447          * Also stores the IDs in the link cache.
3448          *
3449          * WARNING: do not use this function on arbitrary user-supplied titles!
3450          * On heavily-used templates it will max out the memory.
3451          *
3452          * @param array $options Query option to Database::select()
3453          * @param string $table Table name
3454          * @param string $prefix Fields prefix
3455          * @return array Array of Title objects linking here
3456          */
3457         public function getLinksFrom( $options = [], $table = 'pagelinks', $prefix = 'pl' ) {
3458                 $id = $this->getArticleID();
3459
3460                 # If the page doesn't exist; there can't be any link from this page
3461                 if ( !$id ) {
3462                         return [];
3463                 }
3464
3465                 $db = wfGetDB( DB_REPLICA );
3466
3467                 $blNamespace = "{$prefix}_namespace";
3468                 $blTitle = "{$prefix}_title";
3469
3470                 $res = $db->select(
3471                         [ $table, 'page' ],
3472                         array_merge(
3473                                 [ $blNamespace, $blTitle ],
3474                                 WikiPage::selectFields()
3475                         ),
3476                         [ "{$prefix}_from" => $id ],
3477                         __METHOD__,
3478                         $options,
3479                         [ 'page' => [
3480                                 'LEFT JOIN',
3481                                 [ "page_namespace=$blNamespace", "page_title=$blTitle" ]
3482                         ] ]
3483                 );
3484
3485                 $retVal = [];
3486                 $linkCache = LinkCache::singleton();
3487                 foreach ( $res as $row ) {
3488                         if ( $row->page_id ) {
3489                                 $titleObj = Title::newFromRow( $row );
3490                         } else {
3491                                 $titleObj = Title::makeTitle( $row->$blNamespace, $row->$blTitle );
3492                                 $linkCache->addBadLinkObj( $titleObj );
3493                         }
3494                         $retVal[] = $titleObj;
3495                 }
3496
3497                 return $retVal;
3498         }
3499
3500         /**
3501          * Get an array of Title objects used on this Title as a template
3502          * Also stores the IDs in the link cache.
3503          *
3504          * WARNING: do not use this function on arbitrary user-supplied titles!
3505          * On heavily-used templates it will max out the memory.
3506          *
3507          * @param array $options May be FOR UPDATE
3508          * @return Title[] Array of Title the Title objects used here
3509          */
3510         public function getTemplateLinksFrom( $options = [] ) {
3511                 return $this->getLinksFrom( $options, 'templatelinks', 'tl' );
3512         }
3513
3514         /**
3515          * Get an array of Title objects referring to non-existent articles linked
3516          * from this page.
3517          *
3518          * @todo check if needed (used only in SpecialBrokenRedirects.php, and
3519          *   should use redirect table in this case).
3520          * @return Title[] Array of Title the Title objects
3521          */
3522         public function getBrokenLinksFrom() {
3523                 if ( $this->getArticleID() == 0 ) {
3524                         # All links from article ID 0 are false positives
3525                         return [];
3526                 }
3527
3528                 $dbr = wfGetDB( DB_REPLICA );
3529                 $res = $dbr->select(
3530                         [ 'page', 'pagelinks' ],
3531                         [ 'pl_namespace', 'pl_title' ],
3532                         [
3533                                 'pl_from' => $this->getArticleID(),
3534                                 'page_namespace IS NULL'
3535                         ],
3536                         __METHOD__, [],
3537                         [
3538                                 'page' => [
3539                                         'LEFT JOIN',
3540                                         [ 'pl_namespace=page_namespace', 'pl_title=page_title' ]
3541                                 ]
3542                         ]
3543                 );
3544
3545                 $retVal = [];
3546                 foreach ( $res as $row ) {
3547                         $retVal[] = Title::makeTitle( $row->pl_namespace, $row->pl_title );
3548                 }
3549                 return $retVal;
3550         }
3551
3552         /**
3553          * Get a list of URLs to purge from the CDN cache when this
3554          * page changes
3555          *
3556          * @return string[] Array of String the URLs
3557          */
3558         public function getCdnUrls() {
3559                 $urls = [
3560                         $this->getInternalURL(),
3561                         $this->getInternalURL( 'action=history' )
3562                 ];
3563
3564                 $pageLang = $this->getPageLanguage();
3565                 if ( $pageLang->hasVariants() ) {
3566                         $variants = $pageLang->getVariants();
3567                         foreach ( $variants as $vCode ) {
3568                                 $urls[] = $this->getInternalURL( $vCode );
3569                         }
3570                 }
3571
3572                 // If we are looking at a css/js user subpage, purge the action=raw.
3573                 if ( $this->isJsSubpage() ) {
3574                         $urls[] = $this->getInternalURL( 'action=raw&ctype=text/javascript' );
3575                 } elseif ( $this->isCssSubpage() ) {
3576                         $urls[] = $this->getInternalURL( 'action=raw&ctype=text/css' );
3577                 }
3578
3579                 Hooks::run( 'TitleSquidURLs', [ $this, &$urls ] );
3580                 return $urls;
3581         }
3582
3583         /**
3584          * @deprecated since 1.27 use getCdnUrls()
3585          */
3586         public function getSquidURLs() {
3587                 return $this->getCdnUrls();
3588         }
3589
3590         /**
3591          * Purge all applicable CDN URLs
3592          */
3593         public function purgeSquid() {
3594                 DeferredUpdates::addUpdate(
3595                         new CdnCacheUpdate( $this->getCdnUrls() ),
3596                         DeferredUpdates::PRESEND
3597                 );
3598         }
3599
3600         /**
3601          * Move this page without authentication
3602          *
3603          * @deprecated since 1.25 use MovePage class instead
3604          * @param Title $nt The new page Title
3605          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3606          */
3607         public function moveNoAuth( &$nt ) {
3608                 wfDeprecated( __METHOD__, '1.25' );
3609                 return $this->moveTo( $nt, false );
3610         }
3611
3612         /**
3613          * Check whether a given move operation would be valid.
3614          * Returns true if ok, or a getUserPermissionsErrors()-like array otherwise
3615          *
3616          * @deprecated since 1.25, use MovePage's methods instead
3617          * @param Title $nt The new title
3618          * @param bool $auth Whether to check user permissions (uses $wgUser)
3619          * @param string $reason Is the log summary of the move, used for spam checking
3620          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3621          */
3622         public function isValidMoveOperation( &$nt, $auth = true, $reason = '' ) {
3623                 global $wgUser;
3624
3625                 if ( !( $nt instanceof Title ) ) {
3626                         // Normally we'd add this to $errors, but we'll get
3627                         // lots of syntax errors if $nt is not an object
3628                         return [ [ 'badtitletext' ] ];
3629                 }
3630
3631                 $mp = new MovePage( $this, $nt );
3632                 $errors = $mp->isValidMove()->getErrorsArray();
3633                 if ( $auth ) {
3634                         $errors = wfMergeErrorArrays(
3635                                 $errors,
3636                                 $mp->checkPermissions( $wgUser, $reason )->getErrorsArray()
3637                         );
3638                 }
3639
3640                 return $errors ?: true;
3641         }
3642
3643         /**
3644          * Check if the requested move target is a valid file move target
3645          * @todo move this to MovePage
3646          * @param Title $nt Target title
3647          * @return array List of errors
3648          */
3649         protected function validateFileMoveOperation( $nt ) {
3650                 global $wgUser;
3651
3652                 $errors = [];
3653
3654                 $destFile = wfLocalFile( $nt );
3655                 $destFile->load( File::READ_LATEST );
3656                 if ( !$wgUser->isAllowed( 'reupload-shared' )
3657                         && !$destFile->exists() && wfFindFile( $nt )
3658                 ) {
3659                         $errors[] = [ 'file-exists-sharedrepo' ];
3660                 }
3661
3662                 return $errors;
3663         }
3664
3665         /**
3666          * Move a title to a new location
3667          *
3668          * @deprecated since 1.25, use the MovePage class instead
3669          * @param Title $nt The new title
3670          * @param bool $auth Indicates whether $wgUser's permissions
3671          *  should be checked
3672          * @param string $reason The reason for the move
3673          * @param bool $createRedirect Whether to create a redirect from the old title to the new title.
3674          *  Ignored if the user doesn't have the suppressredirect right.
3675          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3676          */
3677         public function moveTo( &$nt, $auth = true, $reason = '', $createRedirect = true ) {
3678                 global $wgUser;
3679                 $err = $this->isValidMoveOperation( $nt, $auth, $reason );
3680                 if ( is_array( $err ) ) {
3681                         // Auto-block user's IP if the account was "hard" blocked
3682                         $wgUser->spreadAnyEditBlock();
3683                         return $err;
3684                 }
3685                 // Check suppressredirect permission
3686                 if ( $auth && !$wgUser->isAllowed( 'suppressredirect' ) ) {
3687                         $createRedirect = true;
3688                 }
3689
3690                 $mp = new MovePage( $this, $nt );
3691                 $status = $mp->move( $wgUser, $reason, $createRedirect );
3692                 if ( $status->isOK() ) {
3693                         return true;
3694                 } else {
3695                         return $status->getErrorsArray();
3696                 }
3697         }
3698
3699         /**
3700          * Move this page's subpages to be subpages of $nt
3701          *
3702          * @param Title $nt Move target
3703          * @param bool $auth Whether $wgUser's permissions should be checked
3704          * @param string $reason The reason for the move
3705          * @param bool $createRedirect Whether to create redirects from the old subpages to
3706          *     the new ones Ignored if the user doesn't have the 'suppressredirect' right
3707          * @return array Array with old page titles as keys, and strings (new page titles) or
3708          *     arrays (errors) as values, or an error array with numeric indices if no pages
3709          *     were moved
3710          */
3711         public function moveSubpages( $nt, $auth = true, $reason = '', $createRedirect = true ) {
3712                 global $wgMaximumMovedPages;
3713                 // Check permissions
3714                 if ( !$this->userCan( 'move-subpages' ) ) {
3715                         return [ 'cant-move-subpages' ];
3716                 }
3717                 // Do the source and target namespaces support subpages?
3718                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3719                         return [ 'namespace-nosubpages',
3720                                 MWNamespace::getCanonicalName( $this->getNamespace() ) ];
3721                 }
3722                 if ( !MWNamespace::hasSubpages( $nt->getNamespace() ) ) {
3723                         return [ 'namespace-nosubpages',
3724                                 MWNamespace::getCanonicalName( $nt->getNamespace() ) ];
3725                 }
3726
3727                 $subpages = $this->getSubpages( $wgMaximumMovedPages + 1 );
3728                 $retval = [];
3729                 $count = 0;
3730                 foreach ( $subpages as $oldSubpage ) {
3731                         $count++;
3732                         if ( $count > $wgMaximumMovedPages ) {
3733                                 $retval[$oldSubpage->getPrefixedText()] =
3734                                                 [ 'movepage-max-pages',
3735                                                         $wgMaximumMovedPages ];
3736                                 break;
3737                         }
3738
3739                         // We don't know whether this function was called before
3740                         // or after moving the root page, so check both
3741                         // $this and $nt
3742                         if ( $oldSubpage->getArticleID() == $this->getArticleID()
3743                                 || $oldSubpage->getArticleID() == $nt->getArticleID()
3744                         ) {
3745                                 // When moving a page to a subpage of itself,
3746                                 // don't move it twice
3747                                 continue;
3748                         }
3749                         $newPageName = preg_replace(
3750                                         '#^' . preg_quote( $this->getDBkey(), '#' ) . '#',
3751                                         StringUtils::escapeRegexReplacement( $nt->getDBkey() ), # bug 21234
3752                                         $oldSubpage->getDBkey() );
3753                         if ( $oldSubpage->isTalkPage() ) {
3754                                 $newNs = $nt->getTalkPage()->getNamespace();
3755                         } else {
3756                                 $newNs = $nt->getSubjectPage()->getNamespace();
3757                         }
3758                         # Bug 14385: we need makeTitleSafe because the new page names may
3759                         # be longer than 255 characters.
3760                         $newSubpage = Title::makeTitleSafe( $newNs, $newPageName );
3761
3762                         $success = $oldSubpage->moveTo( $newSubpage, $auth, $reason, $createRedirect );
3763                         if ( $success === true ) {
3764                                 $retval[$oldSubpage->getPrefixedText()] = $newSubpage->getPrefixedText();
3765                         } else {
3766                                 $retval[$oldSubpage->getPrefixedText()] = $success;
3767                         }
3768                 }
3769                 return $retval;
3770         }
3771
3772         /**
3773          * Checks if this page is just a one-rev redirect.
3774          * Adds lock, so don't use just for light purposes.
3775          *
3776          * @return bool
3777          */
3778         public function isSingleRevRedirect() {
3779                 global $wgContentHandlerUseDB;
3780
3781                 $dbw = wfGetDB( DB_MASTER );
3782
3783                 # Is it a redirect?
3784                 $fields = [ 'page_is_redirect', 'page_latest', 'page_id' ];
3785                 if ( $wgContentHandlerUseDB ) {
3786                         $fields[] = 'page_content_model';
3787                 }
3788
3789                 $row = $dbw->selectRow( 'page',
3790                         $fields,
3791                         $this->pageCond(),
3792                         __METHOD__,
3793                         [ 'FOR UPDATE' ]
3794                 );
3795                 # Cache some fields we may want
3796                 $this->mArticleID = $row ? intval( $row->page_id ) : 0;
3797                 $this->mRedirect = $row ? (bool)$row->page_is_redirect : false;
3798                 $this->mLatestID = $row ? intval( $row->page_latest ) : false;
3799                 $this->mContentModel = $row && isset( $row->page_content_model )
3800                         ? strval( $row->page_content_model )
3801                         : false;
3802
3803                 if ( !$this->mRedirect ) {
3804                         return false;
3805                 }
3806                 # Does the article have a history?
3807                 $row = $dbw->selectField( [ 'page', 'revision' ],
3808                         'rev_id',
3809                         [ 'page_namespace' => $this->getNamespace(),
3810                                 'page_title' => $this->getDBkey(),
3811                                 'page_id=rev_page',
3812                                 'page_latest != rev_id'
3813                         ],
3814                         __METHOD__,
3815                         [ 'FOR UPDATE' ]
3816                 );
3817                 # Return true if there was no history
3818                 return ( $row === false );
3819         }
3820
3821         /**
3822          * Checks if $this can be moved to a given Title
3823          * - Selects for update, so don't call it unless you mean business
3824          *
3825          * @deprecated since 1.25, use MovePage's methods instead
3826          * @param Title $nt The new title to check
3827          * @return bool
3828          */
3829         public function isValidMoveTarget( $nt ) {
3830                 # Is it an existing file?
3831                 if ( $nt->getNamespace() == NS_FILE ) {
3832                         $file = wfLocalFile( $nt );
3833                         $file->load( File::READ_LATEST );
3834                         if ( $file->exists() ) {
3835                                 wfDebug( __METHOD__ . ": file exists\n" );
3836                                 return false;
3837                         }
3838                 }
3839                 # Is it a redirect with no history?
3840                 if ( !$nt->isSingleRevRedirect() ) {
3841                         wfDebug( __METHOD__ . ": not a one-rev redirect\n" );
3842                         return false;
3843                 }
3844                 # Get the article text
3845                 $rev = Revision::newFromTitle( $nt, false, Revision::READ_LATEST );
3846                 if ( !is_object( $rev ) ) {
3847                         return false;
3848                 }
3849                 $content = $rev->getContent();
3850                 # Does the redirect point to the source?
3851                 # Or is it a broken self-redirect, usually caused by namespace collisions?
3852                 $redirTitle = $content ? $content->getRedirectTarget() : null;
3853
3854                 if ( $redirTitle ) {
3855                         if ( $redirTitle->getPrefixedDBkey() != $this->getPrefixedDBkey() &&
3856                                 $redirTitle->getPrefixedDBkey() != $nt->getPrefixedDBkey() ) {
3857                                 wfDebug( __METHOD__ . ": redirect points to other page\n" );
3858                                 return false;
3859                         } else {
3860                                 return true;
3861                         }
3862                 } else {
3863                         # Fail safe (not a redirect after all. strange.)
3864                         wfDebug( __METHOD__ . ": failsafe: database sais " . $nt->getPrefixedDBkey() .
3865                                                 " is a redirect, but it doesn't contain a valid redirect.\n" );
3866                         return false;
3867                 }
3868         }
3869
3870         /**
3871          * Get categories to which this Title belongs and return an array of
3872          * categories' names.
3873          *
3874          * @return array Array of parents in the form:
3875          *        $parent => $currentarticle
3876          */
3877         public function getParentCategories() {
3878                 global $wgContLang;
3879
3880                 $data = [];
3881
3882                 $titleKey = $this->getArticleID();
3883
3884                 if ( $titleKey === 0 ) {
3885                         return $data;
3886                 }
3887
3888                 $dbr = wfGetDB( DB_REPLICA );
3889
3890                 $res = $dbr->select(
3891                         'categorylinks',
3892                         'cl_to',
3893                         [ 'cl_from' => $titleKey ],
3894                         __METHOD__
3895                 );
3896
3897                 if ( $res->numRows() > 0 ) {
3898                         foreach ( $res as $row ) {
3899                                 // $data[] = Title::newFromText($wgContLang->getNsText ( NS_CATEGORY ).':'.$row->cl_to);
3900                                 $data[$wgContLang->getNsText( NS_CATEGORY ) . ':' . $row->cl_to] = $this->getFullText();
3901                         }
3902                 }
3903                 return $data;
3904         }
3905
3906         /**
3907          * Get a tree of parent categories
3908          *
3909          * @param array $children Array with the children in the keys, to check for circular refs
3910          * @return array Tree of parent categories
3911          */
3912         public function getParentCategoryTree( $children = [] ) {
3913                 $stack = [];
3914                 $parents = $this->getParentCategories();
3915
3916                 if ( $parents ) {
3917                         foreach ( $parents as $parent => $current ) {
3918                                 if ( array_key_exists( $parent, $children ) ) {
3919                                         # Circular reference
3920                                         $stack[$parent] = [];
3921                                 } else {
3922                                         $nt = Title::newFromText( $parent );
3923                                         if ( $nt ) {
3924                                                 $stack[$parent] = $nt->getParentCategoryTree( $children + [ $parent => 1 ] );
3925                                         }
3926                                 }
3927                         }
3928                 }
3929
3930                 return $stack;
3931         }
3932
3933         /**
3934          * Get an associative array for selecting this title from
3935          * the "page" table
3936          *
3937          * @return array Array suitable for the $where parameter of DB::select()
3938          */
3939         public function pageCond() {
3940                 if ( $this->mArticleID > 0 ) {
3941                         // PK avoids secondary lookups in InnoDB, shouldn't hurt other DBs
3942                         return [ 'page_id' => $this->mArticleID ];
3943                 } else {
3944                         return [ 'page_namespace' => $this->mNamespace, 'page_title' => $this->mDbkeyform ];
3945                 }
3946         }
3947
3948         /**
3949          * Get the revision ID of the previous revision
3950          *
3951          * @param int $revId Revision ID. Get the revision that was before this one.
3952          * @param int $flags Title::GAID_FOR_UPDATE
3953          * @return int|bool Old revision ID, or false if none exists
3954          */
3955         public function getPreviousRevisionID( $revId, $flags = 0 ) {
3956                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_REPLICA );
3957                 $revId = $db->selectField( 'revision', 'rev_id',
3958                         [
3959                                 'rev_page' => $this->getArticleID( $flags ),
3960                                 'rev_id < ' . intval( $revId )
3961                         ],
3962                         __METHOD__,
3963                         [ 'ORDER BY' => 'rev_id DESC' ]
3964                 );
3965
3966                 if ( $revId === false ) {
3967                         return false;
3968                 } else {
3969                         return intval( $revId );
3970                 }
3971         }
3972
3973         /**
3974          * Get the revision ID of the next revision
3975          *
3976          * @param int $revId Revision ID. Get the revision that was after this one.
3977          * @param int $flags Title::GAID_FOR_UPDATE
3978          * @return int|bool Next revision ID, or false if none exists
3979          */
3980         public function getNextRevisionID( $revId, $flags = 0 ) {
3981                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_REPLICA );
3982                 $revId = $db->selectField( 'revision', 'rev_id',
3983                         [
3984                                 'rev_page' => $this->getArticleID( $flags ),
3985                                 'rev_id > ' . intval( $revId )
3986                         ],
3987                         __METHOD__,
3988                         [ 'ORDER BY' => 'rev_id' ]
3989                 );
3990
3991                 if ( $revId === false ) {
3992                         return false;
3993                 } else {
3994                         return intval( $revId );
3995                 }
3996         }
3997
3998         /**
3999          * Get the first revision of the page
4000          *
4001          * @param int $flags Title::GAID_FOR_UPDATE
4002          * @return Revision|null If page doesn't exist
4003          */
4004         public function getFirstRevision( $flags = 0 ) {
4005                 $pageId = $this->getArticleID( $flags );
4006                 if ( $pageId ) {
4007                         $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_REPLICA );
4008                         $row = $db->selectRow( 'revision', Revision::selectFields(),
4009                                 [ 'rev_page' => $pageId ],
4010                                 __METHOD__,
4011                                 [ 'ORDER BY' => 'rev_timestamp ASC', 'LIMIT' => 1 ]
4012                         );
4013                         if ( $row ) {
4014                                 return new Revision( $row );
4015                         }
4016                 }
4017                 return null;
4018         }
4019
4020         /**
4021          * Get the oldest revision timestamp of this page
4022          *
4023          * @param int $flags Title::GAID_FOR_UPDATE
4024          * @return string MW timestamp
4025          */
4026         public function getEarliestRevTime( $flags = 0 ) {
4027                 $rev = $this->getFirstRevision( $flags );
4028                 return $rev ? $rev->getTimestamp() : null;
4029         }
4030
4031         /**
4032          * Check if this is a new page
4033          *
4034          * @return bool
4035          */
4036         public function isNewPage() {
4037                 $dbr = wfGetDB( DB_REPLICA );
4038                 return (bool)$dbr->selectField( 'page', 'page_is_new', $this->pageCond(), __METHOD__ );
4039         }
4040
4041         /**
4042          * Check whether the number of revisions of this page surpasses $wgDeleteRevisionsLimit
4043          *
4044          * @return bool
4045          */
4046         public function isBigDeletion() {
4047                 global $wgDeleteRevisionsLimit;
4048
4049                 if ( !$wgDeleteRevisionsLimit ) {
4050                         return false;
4051                 }
4052
4053                 if ( $this->mIsBigDeletion === null ) {
4054                         $dbr = wfGetDB( DB_REPLICA );
4055
4056                         $revCount = $dbr->selectRowCount(
4057                                 'revision',
4058                                 '1',
4059                                 [ 'rev_page' => $this->getArticleID() ],
4060                                 __METHOD__,
4061                                 [ 'LIMIT' => $wgDeleteRevisionsLimit + 1 ]
4062                         );
4063
4064                         $this->mIsBigDeletion = $revCount > $wgDeleteRevisionsLimit;
4065                 }
4066
4067                 return $this->mIsBigDeletion;
4068         }
4069
4070         /**
4071          * Get the approximate revision count of this page.
4072          *
4073          * @return int
4074          */
4075         public function estimateRevisionCount() {
4076                 if ( !$this->exists() ) {
4077                         return 0;
4078                 }
4079
4080                 if ( $this->mEstimateRevisions === null ) {
4081                         $dbr = wfGetDB( DB_REPLICA );
4082                         $this->mEstimateRevisions = $dbr->estimateRowCount( 'revision', '*',
4083                                 [ 'rev_page' => $this->getArticleID() ], __METHOD__ );
4084                 }
4085
4086                 return $this->mEstimateRevisions;
4087         }
4088
4089         /**
4090          * Get the number of revisions between the given revision.
4091          * Used for diffs and other things that really need it.
4092          *
4093          * @param int|Revision $old Old revision or rev ID (first before range)
4094          * @param int|Revision $new New revision or rev ID (first after range)
4095          * @param int|null $max Limit of Revisions to count, will be incremented to detect truncations
4096          * @return int Number of revisions between these revisions.
4097          */
4098         public function countRevisionsBetween( $old, $new, $max = null ) {
4099                 if ( !( $old instanceof Revision ) ) {
4100                         $old = Revision::newFromTitle( $this, (int)$old );
4101                 }
4102                 if ( !( $new instanceof Revision ) ) {
4103                         $new = Revision::newFromTitle( $this, (int)$new );
4104                 }
4105                 if ( !$old || !$new ) {
4106                         return 0; // nothing to compare
4107                 }
4108                 $dbr = wfGetDB( DB_REPLICA );
4109                 $conds = [
4110                         'rev_page' => $this->getArticleID(),
4111                         'rev_timestamp > ' . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4112                         'rev_timestamp < ' . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4113                 ];
4114                 if ( $max !== null ) {
4115                         return $dbr->selectRowCount( 'revision', '1',
4116                                 $conds,
4117                                 __METHOD__,
4118                                 [ 'LIMIT' => $max + 1 ] // extra to detect truncation
4119                         );
4120                 } else {
4121                         return (int)$dbr->selectField( 'revision', 'count(*)', $conds, __METHOD__ );
4122                 }
4123         }
4124
4125         /**
4126          * Get the authors between the given revisions or revision IDs.
4127          * Used for diffs and other things that really need it.
4128          *
4129          * @since 1.23
4130          *
4131          * @param int|Revision $old Old revision or rev ID (first before range by default)
4132          * @param int|Revision $new New revision or rev ID (first after range by default)
4133          * @param int $limit Maximum number of authors
4134          * @param string|array $options (Optional): Single option, or an array of options:
4135          *     'include_old' Include $old in the range; $new is excluded.
4136          *     'include_new' Include $new in the range; $old is excluded.
4137          *     'include_both' Include both $old and $new in the range.
4138          *     Unknown option values are ignored.
4139          * @return array|null Names of revision authors in the range; null if not both revisions exist
4140          */
4141         public function getAuthorsBetween( $old, $new, $limit, $options = [] ) {
4142                 if ( !( $old instanceof Revision ) ) {
4143                         $old = Revision::newFromTitle( $this, (int)$old );
4144                 }
4145                 if ( !( $new instanceof Revision ) ) {
4146                         $new = Revision::newFromTitle( $this, (int)$new );
4147                 }
4148                 // XXX: what if Revision objects are passed in, but they don't refer to this title?
4149                 // Add $old->getPage() != $new->getPage() || $old->getPage() != $this->getArticleID()
4150                 // in the sanity check below?
4151                 if ( !$old || !$new ) {
4152                         return null; // nothing to compare
4153                 }
4154                 $authors = [];
4155                 $old_cmp = '>';
4156                 $new_cmp = '<';
4157                 $options = (array)$options;
4158                 if ( in_array( 'include_old', $options ) ) {
4159                         $old_cmp = '>=';
4160                 }
4161                 if ( in_array( 'include_new', $options ) ) {
4162                         $new_cmp = '<=';
4163                 }
4164                 if ( in_array( 'include_both', $options ) ) {
4165                         $old_cmp = '>=';
4166                         $new_cmp = '<=';
4167                 }
4168                 // No DB query needed if $old and $new are the same or successive revisions:
4169                 if ( $old->getId() === $new->getId() ) {
4170                         return ( $old_cmp === '>' && $new_cmp === '<' ) ?
4171                                 [] :
4172                                 [ $old->getUserText( Revision::RAW ) ];
4173                 } elseif ( $old->getId() === $new->getParentId() ) {
4174                         if ( $old_cmp === '>=' && $new_cmp === '<=' ) {
4175                                 $authors[] = $old->getUserText( Revision::RAW );
4176                                 if ( $old->getUserText( Revision::RAW ) != $new->getUserText( Revision::RAW ) ) {
4177                                         $authors[] = $new->getUserText( Revision::RAW );
4178                                 }
4179                         } elseif ( $old_cmp === '>=' ) {
4180                                 $authors[] = $old->getUserText( Revision::RAW );
4181                         } elseif ( $new_cmp === '<=' ) {
4182                                 $authors[] = $new->getUserText( Revision::RAW );
4183                         }
4184                         return $authors;
4185                 }
4186                 $dbr = wfGetDB( DB_REPLICA );
4187                 $res = $dbr->select( 'revision', 'DISTINCT rev_user_text',
4188                         [
4189                                 'rev_page' => $this->getArticleID(),
4190                                 "rev_timestamp $old_cmp " . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4191                                 "rev_timestamp $new_cmp " . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4192                         ], __METHOD__,
4193                         [ 'LIMIT' => $limit + 1 ] // add one so caller knows it was truncated
4194                 );
4195                 foreach ( $res as $row ) {
4196                         $authors[] = $row->rev_user_text;
4197                 }
4198                 return $authors;
4199         }
4200
4201         /**
4202          * Get the number of authors between the given revisions or revision IDs.
4203          * Used for diffs and other things that really need it.
4204          *
4205          * @param int|Revision $old Old revision or rev ID (first before range by default)
4206          * @param int|Revision $new New revision or rev ID (first after range by default)
4207          * @param int $limit Maximum number of authors
4208          * @param string|array $options (Optional): Single option, or an array of options:
4209          *     'include_old' Include $old in the range; $new is excluded.
4210          *     'include_new' Include $new in the range; $old is excluded.
4211          *     'include_both' Include both $old and $new in the range.
4212          *     Unknown option values are ignored.
4213          * @return int Number of revision authors in the range; zero if not both revisions exist
4214          */
4215         public function countAuthorsBetween( $old, $new, $limit, $options = [] ) {
4216                 $authors = $this->getAuthorsBetween( $old, $new, $limit, $options );
4217                 return $authors ? count( $authors ) : 0;
4218         }
4219
4220         /**
4221          * Compare with another title.
4222          *
4223          * @param Title $title
4224          * @return bool
4225          */
4226         public function equals( Title $title ) {
4227                 // Note: === is necessary for proper matching of number-like titles.
4228                 return $this->getInterwiki() === $title->getInterwiki()
4229                         && $this->getNamespace() == $title->getNamespace()
4230                         && $this->getDBkey() === $title->getDBkey();
4231         }
4232
4233         /**
4234          * Check if this title is a subpage of another title
4235          *
4236          * @param Title $title
4237          * @return bool
4238          */
4239         public function isSubpageOf( Title $title ) {
4240                 return $this->getInterwiki() === $title->getInterwiki()
4241                         && $this->getNamespace() == $title->getNamespace()
4242                         && strpos( $this->getDBkey(), $title->getDBkey() . '/' ) === 0;
4243         }
4244
4245         /**
4246          * Check if page exists.  For historical reasons, this function simply
4247          * checks for the existence of the title in the page table, and will
4248          * thus return false for interwiki links, special pages and the like.
4249          * If you want to know if a title can be meaningfully viewed, you should
4250          * probably call the isKnown() method instead.
4251          *
4252          * @param int $flags An optional bit field; may be Title::GAID_FOR_UPDATE to check
4253          *   from master/for update
4254          * @return bool
4255          */
4256         public function exists( $flags = 0 ) {
4257                 $exists = $this->getArticleID( $flags ) != 0;
4258                 Hooks::run( 'TitleExists', [ $this, &$exists ] );
4259                 return $exists;
4260         }
4261
4262         /**
4263          * Should links to this title be shown as potentially viewable (i.e. as
4264          * "bluelinks"), even if there's no record by this title in the page
4265          * table?
4266          *
4267          * This function is semi-deprecated for public use, as well as somewhat
4268          * misleadingly named.  You probably just want to call isKnown(), which
4269          * calls this function internally.
4270          *
4271          * (ISSUE: Most of these checks are cheap, but the file existence check
4272          * can potentially be quite expensive.  Including it here fixes a lot of
4273          * existing code, but we might want to add an optional parameter to skip
4274          * it and any other expensive checks.)
4275          *
4276          * @return bool
4277          */
4278         public function isAlwaysKnown() {
4279                 $isKnown = null;
4280
4281                 /**
4282                  * Allows overriding default behavior for determining if a page exists.
4283                  * If $isKnown is kept as null, regular checks happen. If it's
4284                  * a boolean, this value is returned by the isKnown method.
4285                  *
4286                  * @since 1.20
4287                  *
4288                  * @param Title $title
4289                  * @param bool|null $isKnown
4290                  */
4291                 Hooks::run( 'TitleIsAlwaysKnown', [ $this, &$isKnown ] );
4292
4293                 if ( !is_null( $isKnown ) ) {
4294                         return $isKnown;
4295                 }
4296
4297                 if ( $this->isExternal() ) {
4298                         return true;  // any interwiki link might be viewable, for all we know
4299                 }
4300
4301                 switch ( $this->mNamespace ) {
4302                         case NS_MEDIA:
4303                         case NS_FILE:
4304                                 // file exists, possibly in a foreign repo
4305                                 return (bool)wfFindFile( $this );
4306                         case NS_SPECIAL:
4307                                 // valid special page
4308                                 return SpecialPageFactory::exists( $this->getDBkey() );
4309                         case NS_MAIN:
4310                                 // selflink, possibly with fragment
4311                                 return $this->mDbkeyform == '';
4312                         case NS_MEDIAWIKI:
4313                                 // known system message
4314                                 return $this->hasSourceText() !== false;
4315                         default:
4316                                 return false;
4317                 }
4318         }
4319
4320         /**
4321          * Does this title refer to a page that can (or might) be meaningfully
4322          * viewed?  In particular, this function may be used to determine if
4323          * links to the title should be rendered as "bluelinks" (as opposed to
4324          * "redlinks" to non-existent pages).
4325          * Adding something else to this function will cause inconsistency
4326          * since LinkHolderArray calls isAlwaysKnown() and does its own
4327          * page existence check.
4328          *
4329          * @return bool
4330          */
4331         public function isKnown() {
4332                 return $this->isAlwaysKnown() || $this->exists();
4333         }
4334
4335         /**
4336          * Does this page have source text?
4337          *
4338          * @return bool
4339          */
4340         public function hasSourceText() {
4341                 if ( $this->exists() ) {
4342                         return true;
4343                 }
4344
4345                 if ( $this->mNamespace == NS_MEDIAWIKI ) {
4346                         // If the page doesn't exist but is a known system message, default
4347                         // message content will be displayed, same for language subpages-
4348                         // Use always content language to avoid loading hundreds of languages
4349                         // to get the link color.
4350                         global $wgContLang;
4351                         list( $name, ) = MessageCache::singleton()->figureMessage(
4352                                 $wgContLang->lcfirst( $this->getText() )
4353                         );
4354                         $message = wfMessage( $name )->inLanguage( $wgContLang )->useDatabase( false );
4355                         return $message->exists();
4356                 }
4357
4358                 return false;
4359         }
4360
4361         /**
4362          * Get the default message text or false if the message doesn't exist
4363          *
4364          * @return string|bool
4365          */
4366         public function getDefaultMessageText() {
4367                 global $wgContLang;
4368
4369                 if ( $this->getNamespace() != NS_MEDIAWIKI ) { // Just in case
4370                         return false;
4371                 }
4372
4373                 list( $name, $lang ) = MessageCache::singleton()->figureMessage(
4374                         $wgContLang->lcfirst( $this->getText() )
4375                 );
4376                 $message = wfMessage( $name )->inLanguage( $lang )->useDatabase( false );
4377
4378                 if ( $message->exists() ) {
4379                         return $message->plain();
4380                 } else {
4381                         return false;
4382                 }
4383         }
4384
4385         /**
4386          * Updates page_touched for this page; called from LinksUpdate.php
4387          *
4388          * @param string $purgeTime [optional] TS_MW timestamp
4389          * @return bool True if the update succeeded
4390          */
4391         public function invalidateCache( $purgeTime = null ) {
4392                 if ( wfReadOnly() ) {
4393                         return false;
4394                 }
4395
4396                 if ( $this->mArticleID === 0 ) {
4397                         return true; // avoid gap locking if we know it's not there
4398                 }
4399
4400                 $conds = $this->pageCond();
4401                 DeferredUpdates::addUpdate(
4402                         new AutoCommitUpdate(
4403                                 wfGetDB( DB_MASTER ),
4404                                 __METHOD__,
4405                                 function ( IDatabase $dbw, $fname ) use ( $conds, $purgeTime ) {
4406                                         $dbTimestamp = $dbw->timestamp( $purgeTime ?: time() );
4407                                         $dbw->update(
4408                                                 'page',
4409                                                 [ 'page_touched' => $dbTimestamp ],
4410                                                 $conds + [ 'page_touched < ' . $dbw->addQuotes( $dbTimestamp ) ],
4411                                                 $fname
4412                                         );
4413                                         MediaWikiServices::getInstance()->getLinkCache()->invalidateTitle( $this );
4414                                 }
4415                         ),
4416                         DeferredUpdates::PRESEND
4417                 );
4418
4419                 return true;
4420         }
4421
4422         /**
4423          * Update page_touched timestamps and send CDN purge messages for
4424          * pages linking to this title. May be sent to the job queue depending
4425          * on the number of links. Typically called on create and delete.
4426          */
4427         public function touchLinks() {
4428                 DeferredUpdates::addUpdate( new HTMLCacheUpdate( $this, 'pagelinks' ) );
4429                 if ( $this->getNamespace() == NS_CATEGORY ) {
4430                         DeferredUpdates::addUpdate( new HTMLCacheUpdate( $this, 'categorylinks' ) );
4431                 }
4432         }
4433
4434         /**
4435          * Get the last touched timestamp
4436          *
4437          * @param IDatabase $db Optional db
4438          * @return string Last-touched timestamp
4439          */
4440         public function getTouched( $db = null ) {
4441                 if ( $db === null ) {
4442                         $db = wfGetDB( DB_REPLICA );
4443                 }
4444                 $touched = $db->selectField( 'page', 'page_touched', $this->pageCond(), __METHOD__ );
4445                 return $touched;
4446         }
4447
4448         /**
4449          * Get the timestamp when this page was updated since the user last saw it.
4450          *
4451          * @param User $user
4452          * @return string|null
4453          */
4454         public function getNotificationTimestamp( $user = null ) {
4455                 global $wgUser;
4456
4457                 // Assume current user if none given
4458                 if ( !$user ) {
4459                         $user = $wgUser;
4460                 }
4461                 // Check cache first
4462                 $uid = $user->getId();
4463                 if ( !$uid ) {
4464                         return false;
4465                 }
4466                 // avoid isset here, as it'll return false for null entries
4467                 if ( array_key_exists( $uid, $this->mNotificationTimestamp ) ) {
4468                         return $this->mNotificationTimestamp[$uid];
4469                 }
4470                 // Don't cache too much!
4471                 if ( count( $this->mNotificationTimestamp ) >= self::CACHE_MAX ) {
4472                         $this->mNotificationTimestamp = [];
4473                 }
4474
4475                 $store = MediaWikiServices::getInstance()->getWatchedItemStore();
4476                 $watchedItem = $store->getWatchedItem( $user, $this );
4477                 if ( $watchedItem ) {
4478                         $this->mNotificationTimestamp[$uid] = $watchedItem->getNotificationTimestamp();
4479                 } else {
4480                         $this->mNotificationTimestamp[$uid] = false;
4481                 }
4482
4483                 return $this->mNotificationTimestamp[$uid];
4484         }
4485
4486         /**
4487          * Generate strings used for xml 'id' names in monobook tabs
4488          *
4489          * @param string $prepend Defaults to 'nstab-'
4490          * @return string XML 'id' name
4491          */
4492         public function getNamespaceKey( $prepend = 'nstab-' ) {
4493                 global $wgContLang;
4494                 // Gets the subject namespace if this title
4495                 $namespace = MWNamespace::getSubject( $this->getNamespace() );
4496                 // Checks if canonical namespace name exists for namespace
4497                 if ( MWNamespace::exists( $this->getNamespace() ) ) {
4498                         // Uses canonical namespace name
4499                         $namespaceKey = MWNamespace::getCanonicalName( $namespace );
4500                 } else {
4501                         // Uses text of namespace
4502                         $namespaceKey = $this->getSubjectNsText();
4503                 }
4504                 // Makes namespace key lowercase
4505                 $namespaceKey = $wgContLang->lc( $namespaceKey );
4506                 // Uses main
4507                 if ( $namespaceKey == '' ) {
4508                         $namespaceKey = 'main';
4509                 }
4510                 // Changes file to image for backwards compatibility
4511                 if ( $namespaceKey == 'file' ) {
4512                         $namespaceKey = 'image';
4513                 }
4514                 return $prepend . $namespaceKey;
4515         }
4516
4517         /**
4518          * Get all extant redirects to this Title
4519          *
4520          * @param int|null $ns Single namespace to consider; null to consider all namespaces
4521          * @return Title[] Array of Title redirects to this title
4522          */
4523         public function getRedirectsHere( $ns = null ) {
4524                 $redirs = [];
4525
4526                 $dbr = wfGetDB( DB_REPLICA );
4527                 $where = [
4528                         'rd_namespace' => $this->getNamespace(),
4529                         'rd_title' => $this->getDBkey(),
4530                         'rd_from = page_id'
4531                 ];
4532                 if ( $this->isExternal() ) {
4533                         $where['rd_interwiki'] = $this->getInterwiki();
4534                 } else {
4535                         $where[] = 'rd_interwiki = ' . $dbr->addQuotes( '' ) . ' OR rd_interwiki IS NULL';
4536                 }
4537                 if ( !is_null( $ns ) ) {
4538                         $where['page_namespace'] = $ns;
4539                 }
4540
4541                 $res = $dbr->select(
4542                         [ 'redirect', 'page' ],
4543                         [ 'page_namespace', 'page_title' ],
4544                         $where,
4545                         __METHOD__
4546                 );
4547
4548                 foreach ( $res as $row ) {
4549                         $redirs[] = self::newFromRow( $row );
4550                 }
4551                 return $redirs;
4552         }
4553
4554         /**
4555          * Check if this Title is a valid redirect target
4556          *
4557          * @return bool
4558          */
4559         public function isValidRedirectTarget() {
4560                 global $wgInvalidRedirectTargets;
4561
4562                 if ( $this->isSpecialPage() ) {
4563                         // invalid redirect targets are stored in a global array, but explicitly disallow Userlogout here
4564                         if ( $this->isSpecial( 'Userlogout' ) ) {
4565                                 return false;
4566                         }
4567
4568                         foreach ( $wgInvalidRedirectTargets as $target ) {
4569                                 if ( $this->isSpecial( $target ) ) {
4570                                         return false;
4571                                 }
4572                         }
4573                 }
4574
4575                 return true;
4576         }
4577
4578         /**
4579          * Get a backlink cache object
4580          *
4581          * @return BacklinkCache
4582          */
4583         public function getBacklinkCache() {
4584                 return BacklinkCache::get( $this );
4585         }
4586
4587         /**
4588          * Whether the magic words __INDEX__ and __NOINDEX__ function for  this page.
4589          *
4590          * @return bool
4591          */
4592         public function canUseNoindex() {
4593                 global $wgExemptFromUserRobotsControl;
4594
4595                 $bannedNamespaces = is_null( $wgExemptFromUserRobotsControl )
4596                         ? MWNamespace::getContentNamespaces()
4597                         : $wgExemptFromUserRobotsControl;
4598
4599                 return !in_array( $this->mNamespace, $bannedNamespaces );
4600
4601         }
4602
4603         /**
4604          * Returns the raw sort key to be used for categories, with the specified
4605          * prefix.  This will be fed to Collation::getSortKey() to get a
4606          * binary sortkey that can be used for actual sorting.
4607          *
4608          * @param string $prefix The prefix to be used, specified using
4609          *   {{defaultsort:}} or like [[Category:Foo|prefix]].  Empty for no
4610          *   prefix.
4611          * @return string
4612          */
4613         public function getCategorySortkey( $prefix = '' ) {
4614                 $unprefixed = $this->getText();
4615
4616                 // Anything that uses this hook should only depend
4617                 // on the Title object passed in, and should probably
4618                 // tell the users to run updateCollations.php --force
4619                 // in order to re-sort existing category relations.
4620                 Hooks::run( 'GetDefaultSortkey', [ $this, &$unprefixed ] );
4621                 if ( $prefix !== '' ) {
4622                         # Separate with a line feed, so the unprefixed part is only used as
4623                         # a tiebreaker when two pages have the exact same prefix.
4624                         # In UCA, tab is the only character that can sort above LF
4625                         # so we strip both of them from the original prefix.
4626                         $prefix = strtr( $prefix, "\n\t", '  ' );
4627                         return "$prefix\n$unprefixed";
4628                 }
4629                 return $unprefixed;
4630         }
4631
4632         /**
4633          * Returns the page language code saved in the database, if $wgPageLanguageUseDB is set
4634          * to true in LocalSettings.php, otherwise returns false. If there is no language saved in
4635          * the db, it will return NULL.
4636          *
4637          * @return string|null|bool
4638          */
4639         private function getDbPageLanguageCode() {
4640                 global $wgPageLanguageUseDB;
4641
4642                 // check, if the page language could be saved in the database, and if so and
4643                 // the value is not requested already, lookup the page language using LinkCache
4644                 if ( $wgPageLanguageUseDB && $this->mDbPageLanguage === false ) {
4645                         $linkCache = LinkCache::singleton();
4646                         $linkCache->addLinkObj( $this );
4647                         $this->mDbPageLanguage = $linkCache->getGoodLinkFieldObj( $this, 'lang' );
4648                 }
4649
4650                 return $this->mDbPageLanguage;
4651         }
4652
4653         /**
4654          * Get the language in which the content of this page is written in
4655          * wikitext. Defaults to $wgContLang, but in certain cases it can be
4656          * e.g. $wgLang (such as special pages, which are in the user language).
4657          *
4658          * @since 1.18
4659          * @return Language
4660          */
4661         public function getPageLanguage() {
4662                 global $wgLang, $wgLanguageCode;
4663                 if ( $this->isSpecialPage() ) {
4664                         // special pages are in the user language
4665                         return $wgLang;
4666                 }
4667
4668                 // Checking if DB language is set
4669                 $dbPageLanguage = $this->getDbPageLanguageCode();
4670                 if ( $dbPageLanguage ) {
4671                         return wfGetLangObj( $dbPageLanguage );
4672                 }
4673
4674                 if ( !$this->mPageLanguage || $this->mPageLanguage[1] !== $wgLanguageCode ) {
4675                         // Note that this may depend on user settings, so the cache should
4676                         // be only per-request.
4677                         // NOTE: ContentHandler::getPageLanguage() may need to load the
4678                         // content to determine the page language!
4679                         // Checking $wgLanguageCode hasn't changed for the benefit of unit
4680                         // tests.
4681                         $contentHandler = ContentHandler::getForTitle( $this );
4682                         $langObj = $contentHandler->getPageLanguage( $this );
4683                         $this->mPageLanguage = [ $langObj->getCode(), $wgLanguageCode ];
4684                 } else {
4685                         $langObj = wfGetLangObj( $this->mPageLanguage[0] );
4686                 }
4687
4688                 return $langObj;
4689         }
4690
4691         /**
4692          * Get the language in which the content of this page is written when
4693          * viewed by user. Defaults to $wgContLang, but in certain cases it can be
4694          * e.g. $wgLang (such as special pages, which are in the user language).
4695          *
4696          * @since 1.20
4697          * @return Language
4698          */
4699         public function getPageViewLanguage() {
4700                 global $wgLang;
4701
4702                 if ( $this->isSpecialPage() ) {
4703                         // If the user chooses a variant, the content is actually
4704                         // in a language whose code is the variant code.
4705                         $variant = $wgLang->getPreferredVariant();
4706                         if ( $wgLang->getCode() !== $variant ) {
4707                                 return Language::factory( $variant );
4708                         }
4709
4710                         return $wgLang;
4711                 }
4712
4713                 // Checking if DB language is set
4714                 $dbPageLanguage = $this->getDbPageLanguageCode();
4715                 if ( $dbPageLanguage ) {
4716                         $pageLang = wfGetLangObj( $dbPageLanguage );
4717                         $variant = $pageLang->getPreferredVariant();
4718                         if ( $pageLang->getCode() !== $variant ) {
4719                                 $pageLang = Language::factory( $variant );
4720                         }
4721
4722                         return $pageLang;
4723                 }
4724
4725                 // @note Can't be cached persistently, depends on user settings.
4726                 // @note ContentHandler::getPageViewLanguage() may need to load the
4727                 //   content to determine the page language!
4728                 $contentHandler = ContentHandler::getForTitle( $this );
4729                 $pageLang = $contentHandler->getPageViewLanguage( $this );
4730                 return $pageLang;
4731         }
4732
4733         /**
4734          * Get a list of rendered edit notices for this page.
4735          *
4736          * Array is keyed by the original message key, and values are rendered using parseAsBlock, so
4737          * they will already be wrapped in paragraphs.
4738          *
4739          * @since 1.21
4740          * @param int $oldid Revision ID that's being edited
4741          * @return array
4742          */
4743         public function getEditNotices( $oldid = 0 ) {
4744                 $notices = [];
4745
4746                 // Optional notice for the entire namespace
4747                 $editnotice_ns = 'editnotice-' . $this->getNamespace();
4748                 $msg = wfMessage( $editnotice_ns );
4749                 if ( $msg->exists() ) {
4750                         $html = $msg->parseAsBlock();
4751                         // Edit notices may have complex logic, but output nothing (T91715)
4752                         if ( trim( $html ) !== '' ) {
4753                                 $notices[$editnotice_ns] = Html::rawElement(
4754                                         'div',
4755                                         [ 'class' => [
4756                                                 'mw-editnotice',
4757                                                 'mw-editnotice-namespace',
4758                                                 Sanitizer::escapeClass( "mw-$editnotice_ns" )
4759                                         ] ],
4760                                         $html
4761                                 );
4762                         }
4763                 }
4764
4765                 if ( MWNamespace::hasSubpages( $this->getNamespace() ) ) {
4766                         // Optional notice for page itself and any parent page
4767                         $parts = explode( '/', $this->getDBkey() );
4768                         $editnotice_base = $editnotice_ns;
4769                         while ( count( $parts ) > 0 ) {
4770                                 $editnotice_base .= '-' . array_shift( $parts );
4771                                 $msg = wfMessage( $editnotice_base );
4772                                 if ( $msg->exists() ) {
4773                                         $html = $msg->parseAsBlock();
4774                                         if ( trim( $html ) !== '' ) {
4775                                                 $notices[$editnotice_base] = Html::rawElement(
4776                                                         'div',
4777                                                         [ 'class' => [
4778                                                                 'mw-editnotice',
4779                                                                 'mw-editnotice-base',
4780                                                                 Sanitizer::escapeClass( "mw-$editnotice_base" )
4781                                                         ] ],
4782                                                         $html
4783                                                 );
4784                                         }
4785                                 }
4786                         }
4787                 } else {
4788                         // Even if there are no subpages in namespace, we still don't want "/" in MediaWiki message keys
4789                         $editnoticeText = $editnotice_ns . '-' . strtr( $this->getDBkey(), '/', '-' );
4790                         $msg = wfMessage( $editnoticeText );
4791                         if ( $msg->exists() ) {
4792                                 $html = $msg->parseAsBlock();
4793                                 if ( trim( $html ) !== '' ) {
4794                                         $notices[$editnoticeText] = Html::rawElement(
4795                                                 'div',
4796                                                 [ 'class' => [
4797                                                         'mw-editnotice',
4798                                                         'mw-editnotice-page',
4799                                                         Sanitizer::escapeClass( "mw-$editnoticeText" )
4800                                                 ] ],
4801                                                 $html
4802                                         );
4803                                 }
4804                         }
4805                 }
4806
4807                 Hooks::run( 'TitleGetEditNotices', [ $this, $oldid, &$notices ] );
4808                 return $notices;
4809         }
4810
4811         /**
4812          * @return array
4813          */
4814         public function __sleep() {
4815                 return [
4816                         'mNamespace',
4817                         'mDbkeyform',
4818                         'mFragment',
4819                         'mInterwiki',
4820                         'mLocalInterwiki',
4821                         'mUserCaseDBKey',
4822                         'mDefaultNamespace',
4823                 ];
4824         }
4825
4826         public function __wakeup() {
4827                 $this->mArticleID = ( $this->mNamespace >= 0 ) ? -1 : 0;
4828                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
4829                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
4830         }
4831
4832 }