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 T2696.
 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 (T16952) 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( $this->mInterwiki )->isTranscludable();
 833         }
 834
 835         /**
 836          * Returns the DB name of the distant wiki which owns the object.
 837          *
 838          * @return string|false The DB name
 839          */
 840         public function getTransWikiID() {
 841                 if ( !$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|false 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                 return $isCssOrJsPage;
1237         }
1238
1239         /**
1240          * Is this a .css or .js subpage of a user page?
1241          * @return bool
1242          * @todo FIXME: Rename to isUserConfigPage()
1243          */
1244         public function isCssJsSubpage() {
1245                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1246                                 && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1247                                         || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) ) );
1248         }
1249
1250         /**
1251          * Trim down a .css or .js subpage title to get the corresponding skin name
1252          *
1253          * @return string Containing skin name from .css or .js subpage title
1254          */
1255         public function getSkinFromCssJsSubpage() {
1256                 $subpage = explode( '/', $this->mTextform );
1257                 $subpage = $subpage[count( $subpage ) - 1];
1258                 $lastdot = strrpos( $subpage, '.' );
1259                 if ( $lastdot === false ) {
1260                         return $subpage; # Never happens: only called for names ending in '.css' or '.js'
1261                 }
1262                 return substr( $subpage, 0, $lastdot );
1263         }
1264
1265         /**
1266          * Is this a .css subpage of a user page?
1267          *
1268          * @return bool
1269          */
1270         public function isCssSubpage() {
1271                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1272                         && $this->hasContentModel( CONTENT_MODEL_CSS ) );
1273         }
1274
1275         /**
1276          * Is this a .js subpage of a user page?
1277          *
1278          * @return bool
1279          */
1280         public function isJsSubpage() {
1281                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1282                         && $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1283         }
1284
1285         /**
1286          * Is this a talk page of some sort?
1287          *
1288          * @return bool
1289          */
1290         public function isTalkPage() {
1291                 return MWNamespace::isTalk( $this->getNamespace() );
1292         }
1293
1294         /**
1295          * Get a Title object associated with the talk page of this article
1296          *
1297          * @return Title The object for the talk page
1298          */
1299         public function getTalkPage() {
1300                 return Title::makeTitle( MWNamespace::getTalk( $this->getNamespace() ), $this->getDBkey() );
1301         }
1302
1303         /**
1304          * Get a title object associated with the subject page of this
1305          * talk page
1306          *
1307          * @return Title The object for the subject page
1308          */
1309         public function getSubjectPage() {
1310                 // Is this the same title?
1311                 $subjectNS = MWNamespace::getSubject( $this->getNamespace() );
1312                 if ( $this->getNamespace() == $subjectNS ) {
1313                         return $this;
1314                 }
1315                 return Title::makeTitle( $subjectNS, $this->getDBkey() );
1316         }
1317
1318         /**
1319          * Get the other title for this page, if this is a subject page
1320          * get the talk page, if it is a subject page get the talk page
1321          *
1322          * @since 1.25
1323          * @throws MWException
1324          * @return Title
1325          */
1326         public function getOtherPage() {
1327                 if ( $this->isSpecialPage() ) {
1328                         throw new MWException( 'Special pages cannot have other pages' );
1329                 }
1330                 if ( $this->isTalkPage() ) {
1331                         return $this->getSubjectPage();
1332                 } else {
1333                         return $this->getTalkPage();
1334                 }
1335         }
1336
1337         /**
1338          * Get the default namespace index, for when there is no namespace
1339          *
1340          * @return int Default namespace index
1341          */
1342         public function getDefaultNamespace() {
1343                 return $this->mDefaultNamespace;
1344         }
1345
1346         /**
1347          * Get the Title fragment (i.e.\ the bit after the #) in text form
1348          *
1349          * Use Title::hasFragment to check for a fragment
1350          *
1351          * @return string Title fragment
1352          */
1353         public function getFragment() {
1354                 return $this->mFragment;
1355         }
1356
1357         /**
1358          * Check if a Title fragment is set
1359          *
1360          * @return bool
1361          * @since 1.23
1362          */
1363         public function hasFragment() {
1364                 return $this->mFragment !== '';
1365         }
1366
1367         /**
1368          * Get the fragment in URL form, including the "#" character if there is one
1369          * @return string Fragment in URL form
1370          */
1371         public function getFragmentForURL() {
1372                 if ( !$this->hasFragment() ) {
1373                         return '';
1374                 } else {
1375                         return '#' . Title::escapeFragmentForURL( $this->getFragment() );
1376                 }
1377         }
1378
1379         /**
1380          * Set the fragment for this title. Removes the first character from the
1381          * specified fragment before setting, so it assumes you're passing it with
1382          * an initial "#".
1383          *
1384          * Deprecated for public use, use Title::makeTitle() with fragment parameter,
1385          * or Title::createFragmentTarget().
1386          * Still in active use privately.
1387          *
1388          * @private
1389          * @param string $fragment Text
1390          */
1391         public function setFragment( $fragment ) {
1392                 $this->mFragment = strtr( substr( $fragment, 1 ), '_', ' ' );
1393         }
1394
1395         /**
1396          * Creates a new Title for a different fragment of the same page.
1397          *
1398          * @since 1.27
1399          * @param string $fragment
1400          * @return Title
1401          */
1402         public function createFragmentTarget( $fragment ) {
1403                 return self::makeTitle(
1404                         $this->getNamespace(),
1405                         $this->getText(),
1406                         $fragment,
1407                         $this->getInterwiki()
1408                 );
1409         }
1410
1411         /**
1412          * Prefix some arbitrary text with the namespace or interwiki prefix
1413          * of this object
1414          *
1415          * @param string $name The text
1416          * @return string The prefixed text
1417          */
1418         private function prefix( $name ) {
1419                 $p = '';
1420                 if ( $this->isExternal() ) {
1421                         $p = $this->mInterwiki . ':';
1422                 }
1423
1424                 if ( 0 != $this->mNamespace ) {
1425                         $p .= $this->getNsText() . ':';
1426                 }
1427                 return $p . $name;
1428         }
1429
1430         /**
1431          * Get the prefixed database key form
1432          *
1433          * @return string The prefixed title, with underscores and
1434          *  any interwiki and namespace prefixes
1435          */
1436         public function getPrefixedDBkey() {
1437                 $s = $this->prefix( $this->mDbkeyform );
1438                 $s = strtr( $s, ' ', '_' );
1439                 return $s;
1440         }
1441
1442         /**
1443          * Get the prefixed title with spaces.
1444          * This is the form usually used for display
1445          *
1446          * @return string The prefixed title, with spaces
1447          */
1448         public function getPrefixedText() {
1449                 if ( $this->mPrefixedText === null ) {
1450                         $s = $this->prefix( $this->mTextform );
1451                         $s = strtr( $s, '_', ' ' );
1452                         $this->mPrefixedText = $s;
1453                 }
1454                 return $this->mPrefixedText;
1455         }
1456
1457         /**
1458          * Return a string representation of this title
1459          *
1460          * @return string Representation of this title
1461          */
1462         public function __toString() {
1463                 return $this->getPrefixedText();
1464         }
1465
1466         /**
1467          * Get the prefixed title with spaces, plus any fragment
1468          * (part beginning with '#')
1469          *
1470          * @return string The prefixed title, with spaces and the fragment, including '#'
1471          */
1472         public function getFullText() {
1473                 $text = $this->getPrefixedText();
1474                 if ( $this->hasFragment() ) {
1475                         $text .= '#' . $this->getFragment();
1476                 }
1477                 return $text;
1478         }
1479
1480         /**
1481          * Get the root page name text without a namespace, i.e. the leftmost part before any slashes
1482          *
1483          * @par Example:
1484          * @code
1485          * Title::newFromText('User:Foo/Bar/Baz')->getRootText();
1486          * # returns: 'Foo'
1487          * @endcode
1488          *
1489          * @return string Root name
1490          * @since 1.20
1491          */
1492         public function getRootText() {
1493                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1494                         return $this->getText();
1495                 }
1496
1497                 return strtok( $this->getText(), '/' );
1498         }
1499
1500         /**
1501          * Get the root page name title, i.e. the leftmost part before any slashes
1502          *
1503          * @par Example:
1504          * @code
1505          * Title::newFromText('User:Foo/Bar/Baz')->getRootTitle();
1506          * # returns: Title{User:Foo}
1507          * @endcode
1508          *
1509          * @return Title Root title
1510          * @since 1.20
1511          */
1512         public function getRootTitle() {
1513                 return Title::makeTitle( $this->getNamespace(), $this->getRootText() );
1514         }
1515
1516         /**
1517          * Get the base page name without a namespace, i.e. the part before the subpage name
1518          *
1519          * @par Example:
1520          * @code
1521          * Title::newFromText('User:Foo/Bar/Baz')->getBaseText();
1522          * # returns: 'Foo/Bar'
1523          * @endcode
1524          *
1525          * @return string Base name
1526          */
1527         public function getBaseText() {
1528                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1529                         return $this->getText();
1530                 }
1531
1532                 $parts = explode( '/', $this->getText() );
1533                 # Don't discard the real title if there's no subpage involved
1534                 if ( count( $parts ) > 1 ) {
1535                         unset( $parts[count( $parts ) - 1] );
1536                 }
1537                 return implode( '/', $parts );
1538         }
1539
1540         /**
1541          * Get the base page name title, i.e. the part before the subpage name
1542          *
1543          * @par Example:
1544          * @code
1545          * Title::newFromText('User:Foo/Bar/Baz')->getBaseTitle();
1546          * # returns: Title{User:Foo/Bar}
1547          * @endcode
1548          *
1549          * @return Title Base title
1550          * @since 1.20
1551          */
1552         public function getBaseTitle() {
1553                 return Title::makeTitle( $this->getNamespace(), $this->getBaseText() );
1554         }
1555
1556         /**
1557          * Get the lowest-level subpage name, i.e. the rightmost part after any slashes
1558          *
1559          * @par Example:
1560          * @code
1561          * Title::newFromText('User:Foo/Bar/Baz')->getSubpageText();
1562          * # returns: "Baz"
1563          * @endcode
1564          *
1565          * @return string Subpage name
1566          */
1567         public function getSubpageText() {
1568                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1569                         return $this->mTextform;
1570                 }
1571                 $parts = explode( '/', $this->mTextform );
1572                 return $parts[count( $parts ) - 1];
1573         }
1574
1575         /**
1576          * Get the title for a subpage of the current page
1577          *
1578          * @par Example:
1579          * @code
1580          * Title::newFromText('User:Foo/Bar/Baz')->getSubpage("Asdf");
1581          * # returns: Title{User:Foo/Bar/Baz/Asdf}
1582          * @endcode
1583          *
1584          * @param string $text The subpage name to add to the title
1585          * @return Title Subpage title
1586          * @since 1.20
1587          */
1588         public function getSubpage( $text ) {
1589                 return Title::makeTitleSafe( $this->getNamespace(), $this->getText() . '/' . $text );
1590         }
1591
1592         /**
1593          * Get a URL-encoded form of the subpage text
1594          *
1595          * @return string URL-encoded subpage name
1596          */
1597         public function getSubpageUrlForm() {
1598                 $text = $this->getSubpageText();
1599                 $text = wfUrlencode( strtr( $text, ' ', '_' ) );
1600                 return $text;
1601         }
1602
1603         /**
1604          * Get a URL-encoded title (not an actual URL) including interwiki
1605          *
1606          * @return string The URL-encoded form
1607          */
1608         public function getPrefixedURL() {
1609                 $s = $this->prefix( $this->mDbkeyform );
1610                 $s = wfUrlencode( strtr( $s, ' ', '_' ) );
1611                 return $s;
1612         }
1613
1614         /**
1615          * Helper to fix up the get{Canonical,Full,Link,Local,Internal}URL args
1616          * get{Canonical,Full,Link,Local,Internal}URL methods accepted an optional
1617          * second argument named variant. This was deprecated in favor
1618          * of passing an array of option with a "variant" key
1619          * Once $query2 is removed for good, this helper can be dropped
1620          * and the wfArrayToCgi moved to getLocalURL();
1621          *
1622          * @since 1.19 (r105919)
1623          * @param array|string $query
1624          * @param string|string[]|bool $query2
1625          * @return string
1626          */
1627         private static function fixUrlQueryArgs( $query, $query2 = false ) {
1628                 if ( $query2 !== false ) {
1629                         wfDeprecated( "Title::get{Canonical,Full,Link,Local,Internal}URL " .
1630                                 "method called with a second parameter is deprecated. Add your " .
1631                                 "parameter to an array passed as the first parameter.", "1.19" );
1632                 }
1633                 if ( is_array( $query ) ) {
1634                         $query = wfArrayToCgi( $query );
1635                 }
1636                 if ( $query2 ) {
1637                         if ( is_string( $query2 ) ) {
1638                                 // $query2 is a string, we will consider this to be
1639                                 // a deprecated $variant argument and add it to the query
1640                                 $query2 = wfArrayToCgi( [ 'variant' => $query2 ] );
1641                         } else {
1642                                 $query2 = wfArrayToCgi( $query2 );
1643                         }
1644                         // If we have $query content add a & to it first
1645                         if ( $query ) {
1646                                 $query .= '&';
1647                         }
1648                         // Now append the queries together
1649                         $query .= $query2;
1650                 }
1651                 return $query;
1652         }
1653
1654         /**
1655          * Get a real URL referring to this title, with interwiki link and
1656          * fragment
1657          *
1658          * @see self::getLocalURL for the arguments.
1659          * @see wfExpandUrl
1660          * @param string|string[] $query
1661          * @param string|string[]|bool $query2
1662          * @param string $proto Protocol type to use in URL
1663          * @return string The URL
1664          */
1665         public function getFullURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1666                 $query = self::fixUrlQueryArgs( $query, $query2 );
1667
1668                 # Hand off all the decisions on urls to getLocalURL
1669                 $url = $this->getLocalURL( $query );
1670
1671                 # Expand the url to make it a full url. Note that getLocalURL has the
1672                 # potential to output full urls for a variety of reasons, so we use
1673                 # wfExpandUrl instead of simply prepending $wgServer
1674                 $url = wfExpandUrl( $url, $proto );
1675
1676                 # Finally, add the fragment.
1677                 $url .= $this->getFragmentForURL();
1678                 // Avoid PHP 7.1 warning from passing $this by reference
1679                 $titleRef = $this;
1680                 Hooks::run( 'GetFullURL', [ &$titleRef, &$url, $query ] );
1681                 return $url;
1682         }
1683
1684         /**
1685          * Get a URL with no fragment or server name (relative URL) from a Title object.
1686          * If this page is generated with action=render, however,
1687          * $wgServer is prepended to make an absolute URL.
1688          *
1689          * @see self::getFullURL to always get an absolute URL.
1690          * @see self::getLinkURL to always get a URL that's the simplest URL that will be
1691          *  valid to link, locally, to the current Title.
1692          * @see self::newFromText to produce a Title object.
1693          *
1694          * @param string|string[] $query An optional query string,
1695          *   not used for interwiki links. Can be specified as an associative array as well,
1696          *   e.g., array( 'action' => 'edit' ) (keys and values will be URL-escaped).
1697          *   Some query patterns will trigger various shorturl path replacements.
1698          * @param string|string[]|bool $query2 An optional secondary query array. This one MUST
1699          *   be an array. If a string is passed it will be interpreted as a deprecated
1700          *   variant argument and urlencoded into a variant= argument.
1701          *   This second query argument will be added to the $query
1702          *   The second parameter is deprecated since 1.19. Pass it as a key,value
1703          *   pair in the first parameter array instead.
1704          *
1705          * @return string String of the URL.
1706          */
1707         public function getLocalURL( $query = '', $query2 = false ) {
1708                 global $wgArticlePath, $wgScript, $wgServer, $wgRequest;
1709
1710                 $query = self::fixUrlQueryArgs( $query, $query2 );
1711
1712                 $interwiki = self::getInterwikiLookup()->fetch( $this->mInterwiki );
1713                 if ( $interwiki ) {
1714                         $namespace = $this->getNsText();
1715                         if ( $namespace != '' ) {
1716                                 # Can this actually happen? Interwikis shouldn't be parsed.
1717                                 # Yes! It can in interwiki transclusion. But... it probably shouldn't.
1718                                 $namespace .= ':';
1719                         }
1720                         $url = $interwiki->getURL( $namespace . $this->getDBkey() );
1721                         $url = wfAppendQuery( $url, $query );
1722                 } else {
1723                         $dbkey = wfUrlencode( $this->getPrefixedDBkey() );
1724                         if ( $query == '' ) {
1725                                 $url = str_replace( '$1', $dbkey, $wgArticlePath );
1726                                 // Avoid PHP 7.1 warning from passing $this by reference
1727                                 $titleRef = $this;
1728                                 Hooks::run( 'GetLocalURL::Article', [ &$titleRef, &$url ] );
1729                         } else {
1730                                 global $wgVariantArticlePath, $wgActionPaths, $wgContLang;
1731                                 $url = false;
1732                                 $matches = [];
1733
1734                                 if ( !empty( $wgActionPaths )
1735                                         && preg_match( '/^(.*&|)action=([^&]*)(&(.*)|)$/', $query, $matches )
1736                                 ) {
1737                                         $action = urldecode( $matches[2] );
1738                                         if ( isset( $wgActionPaths[$action] ) ) {
1739                                                 $query = $matches[1];
1740                                                 if ( isset( $matches[4] ) ) {
1741                                                         $query .= $matches[4];
1742                                                 }
1743                                                 $url = str_replace( '$1', $dbkey, $wgActionPaths[$action] );
1744                                                 if ( $query != '' ) {
1745                                                         $url = wfAppendQuery( $url, $query );
1746                                                 }
1747                                         }
1748                                 }
1749
1750                                 if ( $url === false
1751                                         && $wgVariantArticlePath
1752                                         && preg_match( '/^variant=([^&]*)$/', $query, $matches )
1753                                         && $this->getPageLanguage()->equals( $wgContLang )
1754                                         && $this->getPageLanguage()->hasVariants()
1755                                 ) {
1756                                         $variant = urldecode( $matches[1] );
1757                                         if ( $this->getPageLanguage()->hasVariant( $variant ) ) {
1758                                                 // Only do the variant replacement if the given variant is a valid
1759                                                 // variant for the page's language.
1760                                                 $url = str_replace( '$2', urlencode( $variant ), $wgVariantArticlePath );
1761                                                 $url = str_replace( '$1', $dbkey, $url );
1762                                         }
1763                                 }
1764
1765                                 if ( $url === false ) {
1766                                         if ( $query == '-' ) {
1767                                                 $query = '';
1768                                         }
1769                                         $url = "{$wgScript}?title={$dbkey}&{$query}";
1770                                 }
1771                         }
1772                         // Avoid PHP 7.1 warning from passing $this by reference
1773                         $titleRef = $this;
1774                         Hooks::run( 'GetLocalURL::Internal', [ &$titleRef, &$url, $query ] );
1775
1776                         // @todo FIXME: This causes breakage in various places when we
1777                         // actually expected a local URL and end up with dupe prefixes.
1778                         if ( $wgRequest->getVal( 'action' ) == 'render' ) {
1779                                 $url = $wgServer . $url;
1780                         }
1781                 }
1782                 // Avoid PHP 7.1 warning from passing $this by reference
1783                 $titleRef = $this;
1784                 Hooks::run( 'GetLocalURL', [ &$titleRef, &$url, $query ] );
1785                 return $url;
1786         }
1787
1788         /**
1789          * Get a URL that's the simplest URL that will be valid to link, locally,
1790          * to the current Title.  It includes the fragment, but does not include
1791          * the server unless action=render is used (or the link is external).  If
1792          * there's a fragment but the prefixed text is empty, we just return a link
1793          * to the fragment.
1794          *
1795          * The result obviously should not be URL-escaped, but does need to be
1796          * HTML-escaped if it's being output in HTML.
1797          *
1798          * @param string|string[] $query
1799          * @param bool $query2
1800          * @param string|int|bool $proto A PROTO_* constant on how the URL should be expanded,
1801          *                               or false (default) for no expansion
1802          * @see self::getLocalURL for the arguments.
1803          * @return string The URL
1804          */
1805         public function getLinkURL( $query = '', $query2 = false, $proto = false ) {
1806                 if ( $this->isExternal() || $proto !== false ) {
1807                         $ret = $this->getFullURL( $query, $query2, $proto );
1808                 } elseif ( $this->getPrefixedText() === '' && $this->hasFragment() ) {
1809                         $ret = $this->getFragmentForURL();
1810                 } else {
1811                         $ret = $this->getLocalURL( $query, $query2 ) . $this->getFragmentForURL();
1812                 }
1813                 return $ret;
1814         }
1815
1816         /**
1817          * Get the URL form for an internal link.
1818          * - Used in various CDN-related code, in case we have a different
1819          * internal hostname for the server from the exposed one.
1820          *
1821          * This uses $wgInternalServer to qualify the path, or $wgServer
1822          * if $wgInternalServer is not set. If the server variable used is
1823          * protocol-relative, the URL will be expanded to http://
1824          *
1825          * @see self::getLocalURL for the arguments.
1826          * @return string The URL
1827          */
1828         public function getInternalURL( $query = '', $query2 = false ) {
1829                 global $wgInternalServer, $wgServer;
1830                 $query = self::fixUrlQueryArgs( $query, $query2 );
1831                 $server = $wgInternalServer !== false ? $wgInternalServer : $wgServer;
1832                 $url = wfExpandUrl( $server . $this->getLocalURL( $query ), PROTO_HTTP );
1833                 // Avoid PHP 7.1 warning from passing $this by reference
1834                 $titleRef = $this;
1835                 Hooks::run( 'GetInternalURL', [ &$titleRef, &$url, $query ] );
1836                 return $url;
1837         }
1838
1839         /**
1840          * Get the URL for a canonical link, for use in things like IRC and
1841          * e-mail notifications. Uses $wgCanonicalServer and the
1842          * GetCanonicalURL hook.
1843          *
1844          * NOTE: Unlike getInternalURL(), the canonical URL includes the fragment
1845          *
1846          * @see self::getLocalURL for the arguments.
1847          * @return string The URL
1848          * @since 1.18
1849          */
1850         public function getCanonicalURL( $query = '', $query2 = false ) {
1851                 $query = self::fixUrlQueryArgs( $query, $query2 );
1852                 $url = wfExpandUrl( $this->getLocalURL( $query ) . $this->getFragmentForURL(), PROTO_CANONICAL );
1853                 // Avoid PHP 7.1 warning from passing $this by reference
1854                 $titleRef = $this;
1855                 Hooks::run( 'GetCanonicalURL', [ &$titleRef, &$url, $query ] );
1856                 return $url;
1857         }
1858
1859         /**
1860          * Get the edit URL for this Title
1861          *
1862          * @return string The URL, or a null string if this is an interwiki link
1863          */
1864         public function getEditURL() {
1865                 if ( $this->isExternal() ) {
1866                         return '';
1867                 }
1868                 $s = $this->getLocalURL( 'action=edit' );
1869
1870                 return $s;
1871         }
1872
1873         /**
1874          * Can $user perform $action on this page?
1875          * This skips potentially expensive cascading permission checks
1876          * as well as avoids expensive error formatting
1877          *
1878          * Suitable for use for nonessential UI controls in common cases, but
1879          * _not_ for functional access control.
1880          *
1881          * May provide false positives, but should never provide a false negative.
1882          *
1883          * @param string $action Action that permission needs to be checked for
1884          * @param User $user User to check (since 1.19); $wgUser will be used if not provided.
1885          * @return bool
1886          */
1887         public function quickUserCan( $action, $user = null ) {
1888                 return $this->userCan( $action, $user, false );
1889         }
1890
1891         /**
1892          * Can $user perform $action on this page?
1893          *
1894          * @param string $action Action that permission needs to be checked for
1895          * @param User $user User to check (since 1.19); $wgUser will be used if not
1896          *   provided.
1897          * @param string $rigor Same format as Title::getUserPermissionsErrors()
1898          * @return bool
1899          */
1900         public function userCan( $action, $user = null, $rigor = 'secure' ) {
1901                 if ( !$user instanceof User ) {
1902                         global $wgUser;
1903                         $user = $wgUser;
1904                 }
1905
1906                 return !count( $this->getUserPermissionsErrorsInternal( $action, $user, $rigor, true ) );
1907         }
1908
1909         /**
1910          * Can $user perform $action on this page?
1911          *
1912          * @todo FIXME: This *does not* check throttles (User::pingLimiter()).
1913          *
1914          * @param string $action Action that permission needs to be checked for
1915          * @param User $user User to check
1916          * @param string $rigor One of (quick,full,secure)
1917          *   - quick  : does cheap permission checks from replica DBs (usable for GUI creation)
1918          *   - full   : does cheap and expensive checks possibly from a replica DB
1919          *   - secure : does cheap and expensive checks, using the master as needed
1920          * @param array $ignoreErrors Array of Strings Set this to a list of message keys
1921          *   whose corresponding errors may be ignored.
1922          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
1923          */
1924         public function getUserPermissionsErrors(
1925                 $action, $user, $rigor = 'secure', $ignoreErrors = []
1926         ) {
1927                 $errors = $this->getUserPermissionsErrorsInternal( $action, $user, $rigor );
1928
1929                 // Remove the errors being ignored.
1930                 foreach ( $errors as $index => $error ) {
1931                         $errKey = is_array( $error ) ? $error[0] : $error;
1932
1933                         if ( in_array( $errKey, $ignoreErrors ) ) {
1934                                 unset( $errors[$index] );
1935                         }
1936                         if ( $errKey instanceof MessageSpecifier && in_array( $errKey->getKey(), $ignoreErrors ) ) {
1937                                 unset( $errors[$index] );
1938                         }
1939                 }
1940
1941                 return $errors;
1942         }
1943
1944         /**
1945          * Permissions checks that fail most often, and which are easiest to test.
1946          *
1947          * @param string $action The action to check
1948          * @param User $user User to check
1949          * @param array $errors List of current errors
1950          * @param string $rigor Same format as Title::getUserPermissionsErrors()
1951          * @param bool $short Short circuit on first error
1952          *
1953          * @return array List of errors
1954          */
1955         private function checkQuickPermissions( $action, $user, $errors, $rigor, $short ) {
1956                 if ( !Hooks::run( 'TitleQuickPermissions',
1957                         [ $this, $user, $action, &$errors, ( $rigor !== 'quick' ), $short ] )
1958                 ) {
1959                         return $errors;
1960                 }
1961
1962                 if ( $action == 'create' ) {
1963                         if (
1964                                 ( $this->isTalkPage() && !$user->isAllowed( 'createtalk' ) ) ||
1965                                 ( !$this->isTalkPage() && !$user->isAllowed( 'createpage' ) )
1966                         ) {
1967                                 $errors[] = $user->isAnon() ? [ 'nocreatetext' ] : [ 'nocreate-loggedin' ];
1968                         }
1969                 } elseif ( $action == 'move' ) {
1970                         if ( !$user->isAllowed( 'move-rootuserpages' )
1971                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
1972                                 // Show user page-specific message only if the user can move other pages
1973                                 $errors[] = [ 'cant-move-user-page' ];
1974                         }
1975
1976                         // Check if user is allowed to move files if it's a file
1977                         if ( $this->mNamespace == NS_FILE && !$user->isAllowed( 'movefile' ) ) {
1978                                 $errors[] = [ 'movenotallowedfile' ];
1979                         }
1980
1981                         // Check if user is allowed to move category pages if it's a category page
1982                         if ( $this->mNamespace == NS_CATEGORY && !$user->isAllowed( 'move-categorypages' ) ) {
1983                                 $errors[] = [ 'cant-move-category-page' ];
1984                         }
1985
1986                         if ( !$user->isAllowed( 'move' ) ) {
1987                                 // User can't move anything
1988                                 $userCanMove = User::groupHasPermission( 'user', 'move' );
1989                                 $autoconfirmedCanMove = User::groupHasPermission( 'autoconfirmed', 'move' );
1990                                 if ( $user->isAnon() && ( $userCanMove || $autoconfirmedCanMove ) ) {
1991                                         // custom message if logged-in users without any special rights can move
1992                                         $errors[] = [ 'movenologintext' ];
1993                                 } else {
1994                                         $errors[] = [ 'movenotallowed' ];
1995                                 }
1996                         }
1997                 } elseif ( $action == 'move-target' ) {
1998                         if ( !$user->isAllowed( 'move' ) ) {
1999                                 // User can't move anything
2000                                 $errors[] = [ 'movenotallowed' ];
2001                         } elseif ( !$user->isAllowed( 'move-rootuserpages' )
2002                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
2003                                 // Show user page-specific message only if the user can move other pages
2004                                 $errors[] = [ 'cant-move-to-user-page' ];
2005                         } elseif ( !$user->isAllowed( 'move-categorypages' )
2006                                         && $this->mNamespace == NS_CATEGORY ) {
2007                                 // Show category page-specific message only if the user can move other pages
2008                                 $errors[] = [ 'cant-move-to-category-page' ];
2009                         }
2010                 } elseif ( !$user->isAllowed( $action ) ) {
2011                         $errors[] = $this->missingPermissionError( $action, $short );
2012                 }
2013
2014                 return $errors;
2015         }
2016
2017         /**
2018          * Add the resulting error code to the errors array
2019          *
2020          * @param array $errors List of current errors
2021          * @param array $result Result of errors
2022          *
2023          * @return array List of errors
2024          */
2025         private function resultToError( $errors, $result ) {
2026                 if ( is_array( $result ) && count( $result ) && !is_array( $result[0] ) ) {
2027                         // A single array representing an error
2028                         $errors[] = $result;
2029                 } elseif ( is_array( $result ) && is_array( $result[0] ) ) {
2030                         // A nested array representing multiple errors
2031                         $errors = array_merge( $errors, $result );
2032                 } elseif ( $result !== '' && is_string( $result ) ) {
2033                         // A string representing a message-id
2034                         $errors[] = [ $result ];
2035                 } elseif ( $result instanceof MessageSpecifier ) {
2036                         // A message specifier representing an error
2037                         $errors[] = [ $result ];
2038                 } elseif ( $result === false ) {
2039                         // a generic "We don't want them to do that"
2040                         $errors[] = [ 'badaccess-group0' ];
2041                 }
2042                 return $errors;
2043         }
2044
2045         /**
2046          * Check various permission hooks
2047          *
2048          * @param string $action The action to check
2049          * @param User $user User to check
2050          * @param array $errors List of current errors
2051          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2052          * @param bool $short Short circuit on first error
2053          *
2054          * @return array List of errors
2055          */
2056         private function checkPermissionHooks( $action, $user, $errors, $rigor, $short ) {
2057                 // Use getUserPermissionsErrors instead
2058                 $result = '';
2059                 // Avoid PHP 7.1 warning from passing $this by reference
2060                 $titleRef = $this;
2061                 if ( !Hooks::run( 'userCan', [ &$titleRef, &$user, $action, &$result ] ) ) {
2062                         return $result ? [] : [ [ 'badaccess-group0' ] ];
2063                 }
2064                 // Check getUserPermissionsErrors hook
2065                 // Avoid PHP 7.1 warning from passing $this by reference
2066                 $titleRef = $this;
2067                 if ( !Hooks::run( 'getUserPermissionsErrors', [ &$titleRef, &$user, $action, &$result ] ) ) {
2068                         $errors = $this->resultToError( $errors, $result );
2069                 }
2070                 // Check getUserPermissionsErrorsExpensive hook
2071                 if (
2072                         $rigor !== 'quick'
2073                         && !( $short && count( $errors ) > 0 )
2074                         && !Hooks::run( 'getUserPermissionsErrorsExpensive', [ &$titleRef, &$user, $action, &$result ] )
2075                 ) {
2076                         $errors = $this->resultToError( $errors, $result );
2077                 }
2078
2079                 return $errors;
2080         }
2081
2082         /**
2083          * Check permissions on special pages & namespaces
2084          *
2085          * @param string $action The action to check
2086          * @param User $user User to check
2087          * @param array $errors List of current errors
2088          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2089          * @param bool $short Short circuit on first error
2090          *
2091          * @return array List of errors
2092          */
2093         private function checkSpecialsAndNSPermissions( $action, $user, $errors, $rigor, $short ) {
2094                 # Only 'createaccount' can be performed on special pages,
2095                 # which don't actually exist in the DB.
2096                 if ( NS_SPECIAL == $this->mNamespace && $action !== 'createaccount' ) {
2097                         $errors[] = [ 'ns-specialprotected' ];
2098                 }
2099
2100                 # Check $wgNamespaceProtection for restricted namespaces
2101                 if ( $this->isNamespaceProtected( $user ) ) {
2102                         $ns = $this->mNamespace == NS_MAIN ?
2103                                 wfMessage( 'nstab-main' )->text() : $this->getNsText();
2104                         $errors[] = $this->mNamespace == NS_MEDIAWIKI ?
2105                                 [ 'protectedinterface', $action ] : [ 'namespaceprotected', $ns, $action ];
2106                 }
2107
2108                 return $errors;
2109         }
2110
2111         /**
2112          * Check CSS/JS sub-page permissions
2113          *
2114          * @param string $action The action to check
2115          * @param User $user User to check
2116          * @param array $errors List of current errors
2117          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2118          * @param bool $short Short circuit on first error
2119          *
2120          * @return array List of errors
2121          */
2122         private function checkCSSandJSPermissions( $action, $user, $errors, $rigor, $short ) {
2123                 # Protect css/js subpages of user pages
2124                 # XXX: this might be better using restrictions
2125                 # XXX: right 'editusercssjs' is deprecated, for backward compatibility only
2126                 if ( $action != 'patrol' && !$user->isAllowed( 'editusercssjs' ) ) {
2127                         if ( preg_match( '/^' . preg_quote( $user->getName(), '/' ) . '\//', $this->mTextform ) ) {
2128                                 if ( $this->isCssSubpage() && !$user->isAllowedAny( 'editmyusercss', 'editusercss' ) ) {
2129                                         $errors[] = [ 'mycustomcssprotected', $action ];
2130                                 } elseif ( $this->isJsSubpage() && !$user->isAllowedAny( 'editmyuserjs', 'edituserjs' ) ) {
2131                                         $errors[] = [ 'mycustomjsprotected', $action ];
2132                                 }
2133                         } else {
2134                                 if ( $this->isCssSubpage() && !$user->isAllowed( 'editusercss' ) ) {
2135                                         $errors[] = [ 'customcssprotected', $action ];
2136                                 } elseif ( $this->isJsSubpage() && !$user->isAllowed( 'edituserjs' ) ) {
2137                                         $errors[] = [ 'customjsprotected', $action ];
2138                                 }
2139                         }
2140                 }
2141
2142                 return $errors;
2143         }
2144
2145         /**
2146          * Check against page_restrictions table requirements on this
2147          * page. The user must possess all required rights for this
2148          * action.
2149          *
2150          * @param string $action The action to check
2151          * @param User $user User to check
2152          * @param array $errors List of current errors
2153          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2154          * @param bool $short Short circuit on first error
2155          *
2156          * @return array List of errors
2157          */
2158         private function checkPageRestrictions( $action, $user, $errors, $rigor, $short ) {
2159                 foreach ( $this->getRestrictions( $action ) as $right ) {
2160                         // Backwards compatibility, rewrite sysop -> editprotected
2161                         if ( $right == 'sysop' ) {
2162                                 $right = 'editprotected';
2163                         }
2164                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2165                         if ( $right == 'autoconfirmed' ) {
2166                                 $right = 'editsemiprotected';
2167                         }
2168                         if ( $right == '' ) {
2169                                 continue;
2170                         }
2171                         if ( !$user->isAllowed( $right ) ) {
2172                                 $errors[] = [ 'protectedpagetext', $right, $action ];
2173                         } elseif ( $this->mCascadeRestriction && !$user->isAllowed( 'protect' ) ) {
2174                                 $errors[] = [ 'protectedpagetext', 'protect', $action ];
2175                         }
2176                 }
2177
2178                 return $errors;
2179         }
2180
2181         /**
2182          * Check restrictions on cascading pages.
2183          *
2184          * @param string $action The action to check
2185          * @param User $user User to check
2186          * @param array $errors List of current errors
2187          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2188          * @param bool $short Short circuit on first error
2189          *
2190          * @return array List of errors
2191          */
2192         private function checkCascadingSourcesRestrictions( $action, $user, $errors, $rigor, $short ) {
2193                 if ( $rigor !== 'quick' && !$this->isCssJsSubpage() ) {
2194                         # We /could/ use the protection level on the source page, but it's
2195                         # fairly ugly as we have to establish a precedence hierarchy for pages
2196                         # included by multiple cascade-protected pages. So just restrict
2197                         # it to people with 'protect' permission, as they could remove the
2198                         # protection anyway.
2199                         list( $cascadingSources, $restrictions ) = $this->getCascadeProtectionSources();
2200                         # Cascading protection depends on more than this page...
2201                         # Several cascading protected pages may include this page...
2202                         # Check each cascading level
2203                         # This is only for protection restrictions, not for all actions
2204                         if ( isset( $restrictions[$action] ) ) {
2205                                 foreach ( $restrictions[$action] as $right ) {
2206                                         // Backwards compatibility, rewrite sysop -> editprotected
2207                                         if ( $right == 'sysop' ) {
2208                                                 $right = 'editprotected';
2209                                         }
2210                                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2211                                         if ( $right == 'autoconfirmed' ) {
2212                                                 $right = 'editsemiprotected';
2213                                         }
2214                                         if ( $right != '' && !$user->isAllowedAll( 'protect', $right ) ) {
2215                                                 $pages = '';
2216                                                 foreach ( $cascadingSources as $page ) {
2217                                                         $pages .= '* [[:' . $page->getPrefixedText() . "]]\n";
2218                                                 }
2219                                                 $errors[] = [ 'cascadeprotected', count( $cascadingSources ), $pages, $action ];
2220                                         }
2221                                 }
2222                         }
2223                 }
2224
2225                 return $errors;
2226         }
2227
2228         /**
2229          * Check action permissions not already checked in checkQuickPermissions
2230          *
2231          * @param string $action The action to check
2232          * @param User $user User to check
2233          * @param array $errors List of current errors
2234          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2235          * @param bool $short Short circuit on first error
2236          *
2237          * @return array List of errors
2238          */
2239         private function checkActionPermissions( $action, $user, $errors, $rigor, $short ) {
2240                 global $wgDeleteRevisionsLimit, $wgLang;
2241
2242                 if ( $action == 'protect' ) {
2243                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit', $user, $rigor, true ) ) ) {
2244                                 // If they can't edit, they shouldn't protect.
2245                                 $errors[] = [ 'protect-cantedit' ];
2246                         }
2247                 } elseif ( $action == 'create' ) {
2248                         $title_protection = $this->getTitleProtection();
2249                         if ( $title_protection ) {
2250                                 if ( $title_protection['permission'] == ''
2251                                         || !$user->isAllowed( $title_protection['permission'] )
2252                                 ) {
2253                                         $errors[] = [
2254                                                 'titleprotected',
2255                                                 User::whoIs( $title_protection['user'] ),
2256                                                 $title_protection['reason']
2257                                         ];
2258                                 }
2259                         }
2260                 } elseif ( $action == 'move' ) {
2261                         // Check for immobile pages
2262                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2263                                 // Specific message for this case
2264                                 $errors[] = [ 'immobile-source-namespace', $this->getNsText() ];
2265                         } elseif ( !$this->isMovable() ) {
2266                                 // Less specific message for rarer cases
2267                                 $errors[] = [ 'immobile-source-page' ];
2268                         }
2269                 } elseif ( $action == 'move-target' ) {
2270                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2271                                 $errors[] = [ 'immobile-target-namespace', $this->getNsText() ];
2272                         } elseif ( !$this->isMovable() ) {
2273                                 $errors[] = [ 'immobile-target-page' ];
2274                         }
2275                 } elseif ( $action == 'delete' ) {
2276                         $tempErrors = $this->checkPageRestrictions( 'edit', $user, [], $rigor, true );
2277                         if ( !$tempErrors ) {
2278                                 $tempErrors = $this->checkCascadingSourcesRestrictions( 'edit',
2279                                         $user, $tempErrors, $rigor, true );
2280                         }
2281                         if ( $tempErrors ) {
2282                                 // If protection keeps them from editing, they shouldn't be able to delete.
2283                                 $errors[] = [ 'deleteprotected' ];
2284                         }
2285                         if ( $rigor !== 'quick' && $wgDeleteRevisionsLimit
2286                                 && !$this->userCan( 'bigdelete', $user ) && $this->isBigDeletion()
2287                         ) {
2288                                 $errors[] = [ 'delete-toobig', $wgLang->formatNum( $wgDeleteRevisionsLimit ) ];
2289                         }
2290                 }
2291                 return $errors;
2292         }
2293
2294         /**
2295          * Check that the user isn't blocked from editing.
2296          *
2297          * @param string $action The action to check
2298          * @param User $user User to check
2299          * @param array $errors List of current errors
2300          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2301          * @param bool $short Short circuit on first error
2302          *
2303          * @return array List of errors
2304          */
2305         private function checkUserBlock( $action, $user, $errors, $rigor, $short ) {
2306                 global $wgEmailConfirmToEdit, $wgBlockDisablesLogin;
2307                 // Account creation blocks handled at userlogin.
2308                 // Unblocking handled in SpecialUnblock
2309                 if ( $rigor === 'quick' || in_array( $action, [ 'createaccount', 'unblock' ] ) ) {
2310                         return $errors;
2311                 }
2312
2313                 // Optimize for a very common case
2314                 if ( $action === 'read' && !$wgBlockDisablesLogin ) {
2315                         return $errors;
2316                 }
2317
2318                 if ( $wgEmailConfirmToEdit && !$user->isEmailConfirmed() ) {
2319                         $errors[] = [ 'confirmedittext' ];
2320                 }
2321
2322                 $useSlave = ( $rigor !== 'secure' );
2323                 if ( ( $action == 'edit' || $action == 'create' )
2324                         && !$user->isBlockedFrom( $this, $useSlave )
2325                 ) {
2326                         // Don't block the user from editing their own talk page unless they've been
2327                         // explicitly blocked from that too.
2328                 } elseif ( $user->isBlocked() && $user->getBlock()->prevents( $action ) !== false ) {
2329                         // @todo FIXME: Pass the relevant context into this function.
2330                         $errors[] = $user->getBlock()->getPermissionsError( RequestContext::getMain() );
2331                 }
2332
2333                 return $errors;
2334         }
2335
2336         /**
2337          * Check that the user is allowed to read this page.
2338          *
2339          * @param string $action The action to check
2340          * @param User $user User to check
2341          * @param array $errors List of current errors
2342          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2343          * @param bool $short Short circuit on first error
2344          *
2345          * @return array List of errors
2346          */
2347         private function checkReadPermissions( $action, $user, $errors, $rigor, $short ) {
2348                 global $wgWhitelistRead, $wgWhitelistReadRegexp;
2349
2350                 $whitelisted = false;
2351                 if ( User::isEveryoneAllowed( 'read' ) ) {
2352                         # Shortcut for public wikis, allows skipping quite a bit of code
2353                         $whitelisted = true;
2354                 } elseif ( $user->isAllowed( 'read' ) ) {
2355                         # If the user is allowed to read pages, he is allowed to read all pages
2356                         $whitelisted = true;
2357                 } elseif ( $this->isSpecial( 'Userlogin' )
2358                         || $this->isSpecial( 'PasswordReset' )
2359                         || $this->isSpecial( 'Userlogout' )
2360                 ) {
2361                         # Always grant access to the login page.
2362                         # Even anons need to be able to log in.
2363                         $whitelisted = true;
2364                 } elseif ( is_array( $wgWhitelistRead ) && count( $wgWhitelistRead ) ) {
2365                         # Time to check the whitelist
2366                         # Only do these checks is there's something to check against
2367                         $name = $this->getPrefixedText();
2368                         $dbName = $this->getPrefixedDBkey();
2369
2370                         // Check for explicit whitelisting with and without underscores
2371                         if ( in_array( $name, $wgWhitelistRead, true ) || in_array( $dbName, $wgWhitelistRead, true ) ) {
2372                                 $whitelisted = true;
2373                         } elseif ( $this->getNamespace() == NS_MAIN ) {
2374                                 # Old settings might have the title prefixed with
2375                                 # a colon for main-namespace pages
2376                                 if ( in_array( ':' . $name, $wgWhitelistRead ) ) {
2377                                         $whitelisted = true;
2378                                 }
2379                         } elseif ( $this->isSpecialPage() ) {
2380                                 # If it's a special page, ditch the subpage bit and check again
2381                                 $name = $this->getDBkey();
2382                                 list( $name, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $name );
2383                                 if ( $name ) {
2384                                         $pure = SpecialPage::getTitleFor( $name )->getPrefixedText();
2385                                         if ( in_array( $pure, $wgWhitelistRead, true ) ) {
2386                                                 $whitelisted = true;
2387                                         }
2388                                 }
2389                         }
2390                 }
2391
2392                 if ( !$whitelisted && is_array( $wgWhitelistReadRegexp ) && !empty( $wgWhitelistReadRegexp ) ) {
2393                         $name = $this->getPrefixedText();
2394                         // Check for regex whitelisting
2395                         foreach ( $wgWhitelistReadRegexp as $listItem ) {
2396                                 if ( preg_match( $listItem, $name ) ) {
2397                                         $whitelisted = true;
2398                                         break;
2399                                 }
2400                         }
2401                 }
2402
2403                 if ( !$whitelisted ) {
2404                         # If the title is not whitelisted, give extensions a chance to do so...
2405                         Hooks::run( 'TitleReadWhitelist', [ $this, $user, &$whitelisted ] );
2406                         if ( !$whitelisted ) {
2407                                 $errors[] = $this->missingPermissionError( $action, $short );
2408                         }
2409                 }
2410
2411                 return $errors;
2412         }
2413
2414         /**
2415          * Get a description array when the user doesn't have the right to perform
2416          * $action (i.e. when User::isAllowed() returns false)
2417          *
2418          * @param string $action The action to check
2419          * @param bool $short Short circuit on first error
2420          * @return array Array containing an error message key and any parameters
2421          */
2422         private function missingPermissionError( $action, $short ) {
2423                 // We avoid expensive display logic for quickUserCan's and such
2424                 if ( $short ) {
2425                         return [ 'badaccess-group0' ];
2426                 }
2427
2428                 return User::newFatalPermissionDeniedStatus( $action )->getErrorsArray()[0];
2429         }
2430
2431         /**
2432          * Can $user perform $action on this page? This is an internal function,
2433          * with multiple levels of checks depending on performance needs; see $rigor below.
2434          * It does not check wfReadOnly().
2435          *
2436          * @param string $action Action that permission needs to be checked for
2437          * @param User $user User to check
2438          * @param string $rigor One of (quick,full,secure)
2439          *   - quick  : does cheap permission checks from replica DBs (usable for GUI creation)
2440          *   - full   : does cheap and expensive checks possibly from a replica DB
2441          *   - secure : does cheap and expensive checks, using the master as needed
2442          * @param bool $short Set this to true to stop after the first permission error.
2443          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
2444          */
2445         protected function getUserPermissionsErrorsInternal(
2446                 $action, $user, $rigor = 'secure', $short = false
2447         ) {
2448                 if ( $rigor === true ) {
2449                         $rigor = 'secure'; // b/c
2450                 } elseif ( $rigor === false ) {
2451                         $rigor = 'quick'; // b/c
2452                 } elseif ( !in_array( $rigor, [ 'quick', 'full', 'secure' ] ) ) {
2453                         throw new Exception( "Invalid rigor parameter '$rigor'." );
2454                 }
2455
2456                 # Read has special handling
2457                 if ( $action == 'read' ) {
2458                         $checks = [
2459                                 'checkPermissionHooks',
2460                                 'checkReadPermissions',
2461                                 'checkUserBlock', // for wgBlockDisablesLogin
2462                         ];
2463                 # Don't call checkSpecialsAndNSPermissions or checkCSSandJSPermissions
2464                 # here as it will lead to duplicate error messages. This is okay to do
2465                 # since anywhere that checks for create will also check for edit, and
2466                 # those checks are called for edit.
2467                 } elseif ( $action == 'create' ) {
2468                         $checks = [
2469                                 'checkQuickPermissions',
2470                                 'checkPermissionHooks',
2471                                 'checkPageRestrictions',
2472                                 'checkCascadingSourcesRestrictions',
2473                                 'checkActionPermissions',
2474                                 'checkUserBlock'
2475                         ];
2476                 } else {
2477                         $checks = [
2478                                 'checkQuickPermissions',
2479                                 'checkPermissionHooks',
2480                                 'checkSpecialsAndNSPermissions',
2481                                 'checkCSSandJSPermissions',
2482                                 'checkPageRestrictions',
2483                                 'checkCascadingSourcesRestrictions',
2484                                 'checkActionPermissions',
2485                                 'checkUserBlock'
2486                         ];
2487                 }
2488
2489                 $errors = [];
2490                 while ( count( $checks ) > 0 &&
2491                                 !( $short && count( $errors ) > 0 ) ) {
2492                         $method = array_shift( $checks );
2493                         $errors = $this->$method( $action, $user, $errors, $rigor, $short );
2494                 }
2495
2496                 return $errors;
2497         }
2498
2499         /**
2500          * Get a filtered list of all restriction types supported by this wiki.
2501          * @param bool $exists True to get all restriction types that apply to
2502          * titles that do exist, False for all restriction types that apply to
2503          * titles that do not exist
2504          * @return array
2505          */
2506         public static function getFilteredRestrictionTypes( $exists = true ) {
2507                 global $wgRestrictionTypes;
2508                 $types = $wgRestrictionTypes;
2509                 if ( $exists ) {
2510                         # Remove the create restriction for existing titles
2511                         $types = array_diff( $types, [ 'create' ] );
2512                 } else {
2513                         # Only the create and upload restrictions apply to non-existing titles
2514                         $types = array_intersect( $types, [ 'create', 'upload' ] );
2515                 }
2516                 return $types;
2517         }
2518
2519         /**
2520          * Returns restriction types for the current Title
2521          *
2522          * @return array Applicable restriction types
2523          */
2524         public function getRestrictionTypes() {
2525                 if ( $this->isSpecialPage() ) {
2526                         return [];
2527                 }
2528
2529                 $types = self::getFilteredRestrictionTypes( $this->exists() );
2530
2531                 if ( $this->getNamespace() != NS_FILE ) {
2532                         # Remove the upload restriction for non-file titles
2533                         $types = array_diff( $types, [ 'upload' ] );
2534                 }
2535
2536                 Hooks::run( 'TitleGetRestrictionTypes', [ $this, &$types ] );
2537
2538                 wfDebug( __METHOD__ . ': applicable restrictions to [[' .
2539                         $this->getPrefixedText() . ']] are {' . implode( ',', $types ) . "}\n" );
2540
2541                 return $types;
2542         }
2543
2544         /**
2545          * Is this title subject to title protection?
2546          * Title protection is the one applied against creation of such title.
2547          *
2548          * @return array|bool An associative array representing any existent title
2549          *   protection, or false if there's none.
2550          */
2551         public function getTitleProtection() {
2552                 // Can't protect pages in special namespaces
2553                 if ( $this->getNamespace() < 0 ) {
2554                         return false;
2555                 }
2556
2557                 // Can't protect pages that exist.
2558                 if ( $this->exists() ) {
2559                         return false;
2560                 }
2561
2562                 if ( $this->mTitleProtection === null ) {
2563                         $dbr = wfGetDB( DB_REPLICA );
2564                         $res = $dbr->select(
2565                                 'protected_titles',
2566                                 [
2567                                         'user' => 'pt_user',
2568                                         'reason' => 'pt_reason',
2569                                         'expiry' => 'pt_expiry',
2570                                         'permission' => 'pt_create_perm'
2571                                 ],
2572                                 [ 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ],
2573                                 __METHOD__
2574                         );
2575
2576                         // fetchRow returns false if there are no rows.
2577                         $row = $dbr->fetchRow( $res );
2578                         if ( $row ) {
2579                                 if ( $row['permission'] == 'sysop' ) {
2580                                         $row['permission'] = 'editprotected'; // B/C
2581                                 }
2582                                 if ( $row['permission'] == 'autoconfirmed' ) {
2583                                         $row['permission'] = 'editsemiprotected'; // B/C
2584                                 }
2585                                 $row['expiry'] = $dbr->decodeExpiry( $row['expiry'] );
2586                         }
2587                         $this->mTitleProtection = $row;
2588                 }
2589                 return $this->mTitleProtection;
2590         }
2591
2592         /**
2593          * Remove any title protection due to page existing
2594          */
2595         public function deleteTitleProtection() {
2596                 $dbw = wfGetDB( DB_MASTER );
2597
2598                 $dbw->delete(
2599                         'protected_titles',
2600                         [ 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ],
2601                         __METHOD__
2602                 );
2603                 $this->mTitleProtection = false;
2604         }
2605
2606         /**
2607          * Is this page "semi-protected" - the *only* protection levels are listed
2608          * in $wgSemiprotectedRestrictionLevels?
2609          *
2610          * @param string $action Action to check (default: edit)
2611          * @return bool
2612          */
2613         public function isSemiProtected( $action = 'edit' ) {
2614                 global $wgSemiprotectedRestrictionLevels;
2615
2616                 $restrictions = $this->getRestrictions( $action );
2617                 $semi = $wgSemiprotectedRestrictionLevels;
2618                 if ( !$restrictions || !$semi ) {
2619                         // Not protected, or all protection is full protection
2620                         return false;
2621                 }
2622
2623                 // Remap autoconfirmed to editsemiprotected for BC
2624                 foreach ( array_keys( $semi, 'autoconfirmed' ) as $key ) {
2625                         $semi[$key] = 'editsemiprotected';
2626                 }
2627                 foreach ( array_keys( $restrictions, 'autoconfirmed' ) as $key ) {
2628                         $restrictions[$key] = 'editsemiprotected';
2629                 }
2630
2631                 return !array_diff( $restrictions, $semi );
2632         }
2633
2634         /**
2635          * Does the title correspond to a protected article?
2636          *
2637          * @param string $action The action the page is protected from,
2638          * by default checks all actions.
2639          * @return bool
2640          */
2641         public function isProtected( $action = '' ) {
2642                 global $wgRestrictionLevels;
2643
2644                 $restrictionTypes = $this->getRestrictionTypes();
2645
2646                 # Special pages have inherent protection
2647                 if ( $this->isSpecialPage() ) {
2648                         return true;
2649                 }
2650
2651                 # Check regular protection levels
2652                 foreach ( $restrictionTypes as $type ) {
2653                         if ( $action == $type || $action == '' ) {
2654                                 $r = $this->getRestrictions( $type );
2655                                 foreach ( $wgRestrictionLevels as $level ) {
2656                                         if ( in_array( $level, $r ) && $level != '' ) {
2657                                                 return true;
2658                                         }
2659                                 }
2660                         }
2661                 }
2662
2663                 return false;
2664         }
2665
2666         /**
2667          * Determines if $user is unable to edit this page because it has been protected
2668          * by $wgNamespaceProtection.
2669          *
2670          * @param User $user User object to check permissions
2671          * @return bool
2672          */
2673         public function isNamespaceProtected( User $user ) {
2674                 global $wgNamespaceProtection;
2675
2676                 if ( isset( $wgNamespaceProtection[$this->mNamespace] ) ) {
2677                         foreach ( (array)$wgNamespaceProtection[$this->mNamespace] as $right ) {
2678                                 if ( $right != '' && !$user->isAllowed( $right ) ) {
2679                                         return true;
2680                                 }
2681                         }
2682                 }
2683                 return false;
2684         }
2685
2686         /**
2687          * Cascading protection: Return true if cascading restrictions apply to this page, false if not.
2688          *
2689          * @return bool If the page is subject to cascading restrictions.
2690          */
2691         public function isCascadeProtected() {
2692                 list( $sources, /* $restrictions */ ) = $this->getCascadeProtectionSources( false );
2693                 return ( $sources > 0 );
2694         }
2695
2696         /**
2697          * Determines whether cascading protection sources have already been loaded from
2698          * the database.
2699          *
2700          * @param bool $getPages True to check if the pages are loaded, or false to check
2701          * if the status is loaded.
2702          * @return bool Whether or not the specified information has been loaded
2703          * @since 1.23
2704          */
2705         public function areCascadeProtectionSourcesLoaded( $getPages = true ) {
2706                 return $getPages ? $this->mCascadeSources !== null : $this->mHasCascadingRestrictions !== null;
2707         }
2708
2709         /**
2710          * Cascading protection: Get the source of any cascading restrictions on this page.
2711          *
2712          * @param bool $getPages Whether or not to retrieve the actual pages
2713          *        that the restrictions have come from and the actual restrictions
2714          *        themselves.
2715          * @return array Two elements: First is an array of Title objects of the
2716          *        pages from which cascading restrictions have come, false for
2717          *        none, or true if such restrictions exist but $getPages was not
2718          *        set. Second is an array like that returned by
2719          *        Title::getAllRestrictions(), or an empty array if $getPages is
2720          *        false.
2721          */
2722         public function getCascadeProtectionSources( $getPages = true ) {
2723                 $pagerestrictions = [];
2724
2725                 if ( $this->mCascadeSources !== null && $getPages ) {
2726                         return [ $this->mCascadeSources, $this->mCascadingRestrictions ];
2727                 } elseif ( $this->mHasCascadingRestrictions !== null && !$getPages ) {
2728                         return [ $this->mHasCascadingRestrictions, $pagerestrictions ];
2729                 }
2730
2731                 $dbr = wfGetDB( DB_REPLICA );
2732
2733                 if ( $this->getNamespace() == NS_FILE ) {
2734                         $tables = [ 'imagelinks', 'page_restrictions' ];
2735                         $where_clauses = [
2736                                 'il_to' => $this->getDBkey(),
2737                                 'il_from=pr_page',
2738                                 'pr_cascade' => 1
2739                         ];
2740                 } else {
2741                         $tables = [ 'templatelinks', 'page_restrictions' ];
2742                         $where_clauses = [
2743                                 'tl_namespace' => $this->getNamespace(),
2744                                 'tl_title' => $this->getDBkey(),
2745                                 'tl_from=pr_page',
2746                                 'pr_cascade' => 1
2747                         ];
2748                 }
2749
2750                 if ( $getPages ) {
2751                         $cols = [ 'pr_page', 'page_namespace', 'page_title',
2752                                 'pr_expiry', 'pr_type', 'pr_level' ];
2753                         $where_clauses[] = 'page_id=pr_page';
2754                         $tables[] = 'page';
2755                 } else {
2756                         $cols = [ 'pr_expiry' ];
2757                 }
2758
2759                 $res = $dbr->select( $tables, $cols, $where_clauses, __METHOD__ );
2760
2761                 $sources = $getPages ? [] : false;
2762                 $now = wfTimestampNow();
2763
2764                 foreach ( $res as $row ) {
2765                         $expiry = $dbr->decodeExpiry( $row->pr_expiry );
2766                         if ( $expiry > $now ) {
2767                                 if ( $getPages ) {
2768                                         $page_id = $row->pr_page;
2769                                         $page_ns = $row->page_namespace;
2770                                         $page_title = $row->page_title;
2771                                         $sources[$page_id] = Title::makeTitle( $page_ns, $page_title );
2772                                         # Add groups needed for each restriction type if its not already there
2773                                         # Make sure this restriction type still exists
2774
2775                                         if ( !isset( $pagerestrictions[$row->pr_type] ) ) {
2776                                                 $pagerestrictions[$row->pr_type] = [];
2777                                         }
2778
2779                                         if (
2780                                                 isset( $pagerestrictions[$row->pr_type] )
2781                                                 && !in_array( $row->pr_level, $pagerestrictions[$row->pr_type] )
2782                                         ) {
2783                                                 $pagerestrictions[$row->pr_type][] = $row->pr_level;
2784                                         }
2785                                 } else {
2786                                         $sources = true;
2787                                 }
2788                         }
2789                 }
2790
2791                 if ( $getPages ) {
2792                         $this->mCascadeSources = $sources;
2793                         $this->mCascadingRestrictions = $pagerestrictions;
2794                 } else {
2795                         $this->mHasCascadingRestrictions = $sources;
2796                 }
2797
2798                 return [ $sources, $pagerestrictions ];
2799         }
2800
2801         /**
2802          * Accessor for mRestrictionsLoaded
2803          *
2804          * @return bool Whether or not the page's restrictions have already been
2805          * loaded from the database
2806          * @since 1.23
2807          */
2808         public function areRestrictionsLoaded() {
2809                 return $this->mRestrictionsLoaded;
2810         }
2811
2812         /**
2813          * Accessor/initialisation for mRestrictions
2814          *
2815          * @param string $action Action that permission needs to be checked for
2816          * @return array Restriction levels needed to take the action. All levels are
2817          *     required. Note that restriction levels are normally user rights, but 'sysop'
2818          *     and 'autoconfirmed' are also allowed for backwards compatibility. These should
2819          *     be mapped to 'editprotected' and 'editsemiprotected' respectively.
2820          */
2821         public function getRestrictions( $action ) {
2822                 if ( !$this->mRestrictionsLoaded ) {
2823                         $this->loadRestrictions();
2824                 }
2825                 return isset( $this->mRestrictions[$action] )
2826                                 ? $this->mRestrictions[$action]
2827                                 : [];
2828         }
2829
2830         /**
2831          * Accessor/initialisation for mRestrictions
2832          *
2833          * @return array Keys are actions, values are arrays as returned by
2834          *     Title::getRestrictions()
2835          * @since 1.23
2836          */
2837         public function getAllRestrictions() {
2838                 if ( !$this->mRestrictionsLoaded ) {
2839                         $this->loadRestrictions();
2840                 }
2841                 return $this->mRestrictions;
2842         }
2843
2844         /**
2845          * Get the expiry time for the restriction against a given action
2846          *
2847          * @param string $action
2848          * @return string|bool 14-char timestamp, or 'infinity' if the page is protected forever
2849          *     or not protected at all, or false if the action is not recognised.
2850          */
2851         public function getRestrictionExpiry( $action ) {
2852                 if ( !$this->mRestrictionsLoaded ) {
2853                         $this->loadRestrictions();
2854                 }
2855                 return isset( $this->mRestrictionsExpiry[$action] ) ? $this->mRestrictionsExpiry[$action] : false;
2856         }
2857
2858         /**
2859          * Returns cascading restrictions for the current article
2860          *
2861          * @return bool
2862          */
2863         function areRestrictionsCascading() {
2864                 if ( !$this->mRestrictionsLoaded ) {
2865                         $this->loadRestrictions();
2866                 }
2867
2868                 return $this->mCascadeRestriction;
2869         }
2870
2871         /**
2872          * Compiles list of active page restrictions from both page table (pre 1.10)
2873          * and page_restrictions table for this existing page.
2874          * Public for usage by LiquidThreads.
2875          *
2876          * @param array $rows Array of db result objects
2877          * @param string $oldFashionedRestrictions Comma-separated list of page
2878          *   restrictions from page table (pre 1.10)
2879          */
2880         public function loadRestrictionsFromRows( $rows, $oldFashionedRestrictions = null ) {
2881                 $dbr = wfGetDB( DB_REPLICA );
2882
2883                 $restrictionTypes = $this->getRestrictionTypes();
2884
2885                 foreach ( $restrictionTypes as $type ) {
2886                         $this->mRestrictions[$type] = [];
2887                         $this->mRestrictionsExpiry[$type] = 'infinity';
2888                 }
2889
2890                 $this->mCascadeRestriction = false;
2891
2892                 # Backwards-compatibility: also load the restrictions from the page record (old format).
2893                 if ( $oldFashionedRestrictions !== null ) {
2894                         $this->mOldRestrictions = $oldFashionedRestrictions;
2895                 }
2896
2897                 if ( $this->mOldRestrictions === false ) {
2898                         $this->mOldRestrictions = $dbr->selectField( 'page', 'page_restrictions',
2899                                 [ 'page_id' => $this->getArticleID() ], __METHOD__ );
2900                 }
2901
2902                 if ( $this->mOldRestrictions != '' ) {
2903                         foreach ( explode( ':', trim( $this->mOldRestrictions ) ) as $restrict ) {
2904                                 $temp = explode( '=', trim( $restrict ) );
2905                                 if ( count( $temp ) == 1 ) {
2906                                         // old old format should be treated as edit/move restriction
2907                                         $this->mRestrictions['edit'] = explode( ',', trim( $temp[0] ) );
2908                                         $this->mRestrictions['move'] = explode( ',', trim( $temp[0] ) );
2909                                 } else {
2910                                         $restriction = trim( $temp[1] );
2911                                         if ( $restriction != '' ) { // some old entries are empty
2912                                                 $this->mRestrictions[$temp[0]] = explode( ',', $restriction );
2913                                         }
2914                                 }
2915                         }
2916                 }
2917
2918                 if ( count( $rows ) ) {
2919                         # Current system - load second to make them override.
2920                         $now = wfTimestampNow();
2921
2922                         # Cycle through all the restrictions.
2923                         foreach ( $rows as $row ) {
2924                                 // Don't take care of restrictions types that aren't allowed
2925                                 if ( !in_array( $row->pr_type, $restrictionTypes ) ) {
2926                                         continue;
2927                                 }
2928
2929                                 // This code should be refactored, now that it's being used more generally,
2930                                 // But I don't really see any harm in leaving it in Block for now -werdna
2931                                 $expiry = $dbr->decodeExpiry( $row->pr_expiry );
2932
2933                                 // Only apply the restrictions if they haven't expired!
2934                                 if ( !$expiry || $expiry > $now ) {
2935                                         $this->mRestrictionsExpiry[$row->pr_type] = $expiry;
2936                                         $this->mRestrictions[$row->pr_type] = explode( ',', trim( $row->pr_level ) );
2937
2938                                         $this->mCascadeRestriction |= $row->pr_cascade;
2939                                 }
2940                         }
2941                 }
2942
2943                 $this->mRestrictionsLoaded = true;
2944         }
2945
2946         /**
2947          * Load restrictions from the page_restrictions table
2948          *
2949          * @param string $oldFashionedRestrictions Comma-separated list of page
2950          *   restrictions from page table (pre 1.10)
2951          */
2952         public function loadRestrictions( $oldFashionedRestrictions = null ) {
2953                 if ( $this->mRestrictionsLoaded ) {
2954                         return;
2955                 }
2956
2957                 $id = $this->getArticleID();
2958                 if ( $id ) {
2959                         $cache = ObjectCache::getMainWANInstance();
2960                         $rows = $cache->getWithSetCallback(
2961                                 // Page protections always leave a new null revision
2962                                 $cache->makeKey( 'page-restrictions', $id, $this->getLatestRevID() ),
2963                                 $cache::TTL_DAY,
2964                                 function ( $curValue, &$ttl, array &$setOpts ) {
2965                                         $dbr = wfGetDB( DB_REPLICA );
2966
2967                                         $setOpts += Database::getCacheSetOptions( $dbr );
2968
2969                                         return iterator_to_array(
2970                                                 $dbr->select(
2971                                                         'page_restrictions',
2972                                                         [ 'pr_type', 'pr_expiry', 'pr_level', 'pr_cascade' ],
2973                                                         [ 'pr_page' => $this->getArticleID() ],
2974                                                         __METHOD__
2975                                                 )
2976                                         );
2977                                 }
2978                         );
2979
2980                         $this->loadRestrictionsFromRows( $rows, $oldFashionedRestrictions );
2981                 } else {
2982                         $title_protection = $this->getTitleProtection();
2983
2984                         if ( $title_protection ) {
2985                                 $now = wfTimestampNow();
2986                                 $expiry = wfGetDB( DB_REPLICA )->decodeExpiry( $title_protection['expiry'] );
2987
2988                                 if ( !$expiry || $expiry > $now ) {
2989                                         // Apply the restrictions
2990                                         $this->mRestrictionsExpiry['create'] = $expiry;
2991                                         $this->mRestrictions['create'] =
2992                                                 explode( ',', trim( $title_protection['permission'] ) );
2993                                 } else { // Get rid of the old restrictions
2994                                         $this->mTitleProtection = false;
2995                                 }
2996                         } else {
2997                                 $this->mRestrictionsExpiry['create'] = 'infinity';
2998                         }
2999                         $this->mRestrictionsLoaded = true;
3000                 }
3001         }
3002
3003         /**
3004          * Flush the protection cache in this object and force reload from the database.
3005          * This is used when updating protection from WikiPage::doUpdateRestrictions().
3006          */
3007         public function flushRestrictions() {
3008                 $this->mRestrictionsLoaded = false;
3009                 $this->mTitleProtection = null;
3010         }
3011
3012         /**
3013          * Purge expired restrictions from the page_restrictions table
3014          *
3015          * This will purge no more than $wgUpdateRowsPerQuery page_restrictions rows
3016          */
3017         static function purgeExpiredRestrictions() {
3018                 if ( wfReadOnly() ) {
3019                         return;
3020                 }
3021
3022                 DeferredUpdates::addUpdate( new AtomicSectionUpdate(
3023                         wfGetDB( DB_MASTER ),
3024                         __METHOD__,
3025                         function ( IDatabase $dbw, $fname ) {
3026                                 $config = MediaWikiServices::getInstance()->getMainConfig();
3027                                 $ids = $dbw->selectFieldValues(
3028                                         'page_restrictions',
3029                                         'pr_id',
3030                                         [ 'pr_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ],
3031                                         $fname,
3032                                         [ 'LIMIT' => $config->get( 'UpdateRowsPerQuery' ) ] // T135470
3033                                 );
3034                                 if ( $ids ) {
3035                                         $dbw->delete( 'page_restrictions', [ 'pr_id' => $ids ], $fname );
3036                                 }
3037                         }
3038                 ) );
3039
3040                 DeferredUpdates::addUpdate( new AtomicSectionUpdate(
3041                         wfGetDB( DB_MASTER ),
3042                         __METHOD__,
3043                         function ( IDatabase $dbw, $fname ) {
3044                                 $dbw->delete(
3045                                         'protected_titles',
3046                                         [ 'pt_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ],
3047                                         $fname
3048                                 );
3049                         }
3050                 ) );
3051         }
3052
3053         /**
3054          * Does this have subpages?  (Warning, usually requires an extra DB query.)
3055          *
3056          * @return bool
3057          */
3058         public function hasSubpages() {
3059                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
3060                         # Duh
3061                         return false;
3062                 }
3063
3064                 # We dynamically add a member variable for the purpose of this method
3065                 # alone to cache the result.  There's no point in having it hanging
3066                 # around uninitialized in every Title object; therefore we only add it
3067                 # if needed and don't declare it statically.
3068                 if ( $this->mHasSubpages === null ) {
3069                         $this->mHasSubpages = false;
3070                         $subpages = $this->getSubpages( 1 );
3071                         if ( $subpages instanceof TitleArray ) {
3072                                 $this->mHasSubpages = (bool)$subpages->count();
3073                         }
3074                 }
3075
3076                 return $this->mHasSubpages;
3077         }
3078
3079         /**
3080          * Get all subpages of this page.
3081          *
3082          * @param int $limit Maximum number of subpages to fetch; -1 for no limit
3083          * @return TitleArray|array TitleArray, or empty array if this page's namespace
3084          *  doesn't allow subpages
3085          */
3086         public function getSubpages( $limit = -1 ) {
3087                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3088                         return [];
3089                 }
3090
3091                 $dbr = wfGetDB( DB_REPLICA );
3092                 $conds['page_namespace'] = $this->getNamespace();
3093                 $conds[] = 'page_title ' . $dbr->buildLike( $this->getDBkey() . '/', $dbr->anyString() );
3094                 $options = [];
3095                 if ( $limit > -1 ) {
3096                         $options['LIMIT'] = $limit;
3097                 }
3098                 $this->mSubpages = TitleArray::newFromResult(
3099                         $dbr->select( 'page',
3100                                 [ 'page_id', 'page_namespace', 'page_title', 'page_is_redirect' ],
3101                                 $conds,
3102                                 __METHOD__,
3103                                 $options
3104                         )
3105                 );
3106                 return $this->mSubpages;
3107         }
3108
3109         /**
3110          * Is there a version of this page in the deletion archive?
3111          *
3112          * @return int The number of archived revisions
3113          */
3114         public function isDeleted() {
3115                 if ( $this->getNamespace() < 0 ) {
3116                         $n = 0;
3117                 } else {
3118                         $dbr = wfGetDB( DB_REPLICA );
3119
3120                         $n = $dbr->selectField( 'archive', 'COUNT(*)',
3121                                 [ 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ],
3122                                 __METHOD__
3123                         );
3124                         if ( $this->getNamespace() == NS_FILE ) {
3125                                 $n += $dbr->selectField( 'filearchive', 'COUNT(*)',
3126                                         [ 'fa_name' => $this->getDBkey() ],
3127                                         __METHOD__
3128                                 );
3129                         }
3130                 }
3131                 return (int)$n;
3132         }
3133
3134         /**
3135          * Is there a version of this page in the deletion archive?
3136          *
3137          * @return bool
3138          */
3139         public function isDeletedQuick() {
3140                 if ( $this->getNamespace() < 0 ) {
3141                         return false;
3142                 }
3143                 $dbr = wfGetDB( DB_REPLICA );
3144                 $deleted = (bool)$dbr->selectField( 'archive', '1',
3145                         [ 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ],
3146                         __METHOD__
3147                 );
3148                 if ( !$deleted && $this->getNamespace() == NS_FILE ) {
3149                         $deleted = (bool)$dbr->selectField( 'filearchive', '1',
3150                                 [ 'fa_name' => $this->getDBkey() ],
3151                                 __METHOD__
3152                         );
3153                 }
3154                 return $deleted;
3155         }
3156
3157         /**
3158          * Get the article ID for this Title from the link cache,
3159          * adding it if necessary
3160          *
3161          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select
3162          *  for update
3163          * @return int The ID
3164          */
3165         public function getArticleID( $flags = 0 ) {
3166                 if ( $this->getNamespace() < 0 ) {
3167                         $this->mArticleID = 0;
3168                         return $this->mArticleID;
3169                 }
3170                 $linkCache = LinkCache::singleton();
3171                 if ( $flags & self::GAID_FOR_UPDATE ) {
3172                         $oldUpdate = $linkCache->forUpdate( true );
3173                         $linkCache->clearLink( $this );
3174                         $this->mArticleID = $linkCache->addLinkObj( $this );
3175                         $linkCache->forUpdate( $oldUpdate );
3176                 } else {
3177                         if ( -1 == $this->mArticleID ) {
3178                                 $this->mArticleID = $linkCache->addLinkObj( $this );
3179                         }
3180                 }
3181                 return $this->mArticleID;
3182         }
3183
3184         /**
3185          * Is this an article that is a redirect page?
3186          * Uses link cache, adding it if necessary
3187          *
3188          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3189          * @return bool
3190          */
3191         public function isRedirect( $flags = 0 ) {
3192                 if ( !is_null( $this->mRedirect ) ) {
3193                         return $this->mRedirect;
3194                 }
3195                 if ( !$this->getArticleID( $flags ) ) {
3196                         $this->mRedirect = false;
3197                         return $this->mRedirect;
3198                 }
3199
3200                 $linkCache = LinkCache::singleton();
3201                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3202                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'redirect' );
3203                 if ( $cached === null ) {
3204                         # Trust LinkCache's state over our own
3205                         # LinkCache is telling us that the page doesn't exist, despite there being cached
3206                         # data relating to an existing page in $this->mArticleID. Updaters should clear
3207                         # LinkCache as appropriate, or use $flags = Title::GAID_FOR_UPDATE. If that flag is
3208                         # set, then LinkCache will definitely be up to date here, since getArticleID() forces
3209                         # LinkCache to refresh its data from the master.
3210                         $this->mRedirect = false;
3211                         return $this->mRedirect;
3212                 }
3213
3214                 $this->mRedirect = (bool)$cached;
3215
3216                 return $this->mRedirect;
3217         }
3218
3219         /**
3220          * What is the length of this page?
3221          * Uses link cache, adding it if necessary
3222          *
3223          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3224          * @return int
3225          */
3226         public function getLength( $flags = 0 ) {
3227                 if ( $this->mLength != -1 ) {
3228                         return $this->mLength;
3229                 }
3230                 if ( !$this->getArticleID( $flags ) ) {
3231                         $this->mLength = 0;
3232                         return $this->mLength;
3233                 }
3234                 $linkCache = LinkCache::singleton();
3235                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3236                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'length' );
3237                 if ( $cached === null ) {
3238                         # Trust LinkCache's state over our own, as for isRedirect()
3239                         $this->mLength = 0;
3240                         return $this->mLength;
3241                 }
3242
3243                 $this->mLength = intval( $cached );
3244
3245                 return $this->mLength;
3246         }
3247
3248         /**
3249          * What is the page_latest field for this page?
3250          *
3251          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3252          * @return int Int or 0 if the page doesn't exist
3253          */
3254         public function getLatestRevID( $flags = 0 ) {
3255                 if ( !( $flags & Title::GAID_FOR_UPDATE ) && $this->mLatestID !== false ) {
3256                         return intval( $this->mLatestID );
3257                 }
3258                 if ( !$this->getArticleID( $flags ) ) {
3259                         $this->mLatestID = 0;
3260                         return $this->mLatestID;
3261                 }
3262                 $linkCache = LinkCache::singleton();
3263                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3264                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'revision' );
3265                 if ( $cached === null ) {
3266                         # Trust LinkCache's state over our own, as for isRedirect()
3267                         $this->mLatestID = 0;
3268                         return $this->mLatestID;
3269                 }
3270
3271                 $this->mLatestID = intval( $cached );
3272
3273                 return $this->mLatestID;
3274         }
3275
3276         /**
3277          * This clears some fields in this object, and clears any associated
3278          * keys in the "bad links" section of the link cache.
3279          *
3280          * - This is called from WikiPage::doEditContent() and WikiPage::insertOn() to allow
3281          * loading of the new page_id. It's also called from
3282          * WikiPage::doDeleteArticleReal()
3283          *
3284          * @param int $newid The new Article ID
3285          */
3286         public function resetArticleID( $newid ) {
3287                 $linkCache = LinkCache::singleton();
3288                 $linkCache->clearLink( $this );
3289
3290                 if ( $newid === false ) {
3291                         $this->mArticleID = -1;
3292                 } else {
3293                         $this->mArticleID = intval( $newid );
3294                 }
3295                 $this->mRestrictionsLoaded = false;
3296                 $this->mRestrictions = [];
3297                 $this->mOldRestrictions = false;
3298                 $this->mRedirect = null;
3299                 $this->mLength = -1;
3300                 $this->mLatestID = false;
3301                 $this->mContentModel = false;
3302                 $this->mEstimateRevisions = null;
3303                 $this->mPageLanguage = false;
3304                 $this->mDbPageLanguage = false;
3305                 $this->mIsBigDeletion = null;
3306         }
3307
3308         public static function clearCaches() {
3309                 $linkCache = LinkCache::singleton();
3310                 $linkCache->clear();
3311
3312                 $titleCache = self::getTitleCache();
3313                 $titleCache->clear();
3314         }
3315
3316         /**
3317          * Capitalize a text string for a title if it belongs to a namespace that capitalizes
3318          *
3319          * @param string $text Containing title to capitalize
3320          * @param int $ns Namespace index, defaults to NS_MAIN
3321          * @return string Containing capitalized title
3322          */
3323         public static function capitalize( $text, $ns = NS_MAIN ) {
3324                 global $wgContLang;
3325
3326                 if ( MWNamespace::isCapitalized( $ns ) ) {
3327                         return $wgContLang->ucfirst( $text );
3328                 } else {
3329                         return $text;
3330                 }
3331         }
3332
3333         /**
3334          * Secure and split - main initialisation function for this object
3335          *
3336          * Assumes that mDbkeyform has been set, and is urldecoded
3337          * and uses underscores, but not otherwise munged.  This function
3338          * removes illegal characters, splits off the interwiki and
3339          * namespace prefixes, sets the other forms, and canonicalizes
3340          * everything.
3341          *
3342          * @throws MalformedTitleException On invalid titles
3343          * @return bool True on success
3344          */
3345         private function secureAndSplit() {
3346                 # Initialisation
3347                 $this->mInterwiki = '';
3348                 $this->mFragment = '';
3349                 $this->mNamespace = $this->mDefaultNamespace; # Usually NS_MAIN
3350
3351                 $dbkey = $this->mDbkeyform;
3352
3353                 // @note: splitTitleString() is a temporary hack to allow MediaWikiTitleCodec to share
3354                 //        the parsing code with Title, while avoiding massive refactoring.
3355                 // @todo: get rid of secureAndSplit, refactor parsing code.
3356                 // @note: getTitleParser() returns a TitleParser implementation which does not have a
3357                 //        splitTitleString method, but the only implementation (MediaWikiTitleCodec) does
3358                 $titleCodec = MediaWikiServices::getInstance()->getTitleParser();
3359                 // MalformedTitleException can be thrown here
3360                 $parts = $titleCodec->splitTitleString( $dbkey, $this->getDefaultNamespace() );
3361
3362                 # Fill fields
3363                 $this->setFragment( '#' . $parts['fragment'] );
3364                 $this->mInterwiki = $parts['interwiki'];
3365                 $this->mLocalInterwiki = $parts['local_interwiki'];
3366                 $this->mNamespace = $parts['namespace'];
3367                 $this->mUserCaseDBKey = $parts['user_case_dbkey'];
3368
3369                 $this->mDbkeyform = $parts['dbkey'];
3370                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
3371                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
3372
3373                 # We already know that some pages won't be in the database!
3374                 if ( $this->isExternal() || $this->mNamespace == NS_SPECIAL ) {
3375                         $this->mArticleID = 0;
3376                 }
3377
3378                 return true;
3379         }
3380
3381         /**
3382          * Get an array of Title objects linking to this Title
3383          * Also stores the IDs in the link cache.
3384          *
3385          * WARNING: do not use this function on arbitrary user-supplied titles!
3386          * On heavily-used templates it will max out the memory.
3387          *
3388          * @param array $options May be FOR UPDATE
3389          * @param string $table Table name
3390          * @param string $prefix Fields prefix
3391          * @return Title[] Array of Title objects linking here
3392          */
3393         public function getLinksTo( $options = [], $table = 'pagelinks', $prefix = 'pl' ) {
3394                 if ( count( $options ) > 0 ) {
3395                         $db = wfGetDB( DB_MASTER );
3396                 } else {
3397                         $db = wfGetDB( DB_REPLICA );
3398                 }
3399
3400                 $res = $db->select(
3401                         [ 'page', $table ],
3402                         self::getSelectFields(),
3403                         [
3404                                 "{$prefix}_from=page_id",
3405                                 "{$prefix}_namespace" => $this->getNamespace(),
3406                                 "{$prefix}_title" => $this->getDBkey() ],
3407                         __METHOD__,
3408                         $options
3409                 );
3410
3411                 $retVal = [];
3412                 if ( $res->numRows() ) {
3413                         $linkCache = LinkCache::singleton();
3414                         foreach ( $res as $row ) {
3415                                 $titleObj = Title::makeTitle( $row->page_namespace, $row->page_title );
3416                                 if ( $titleObj ) {
3417                                         $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3418                                         $retVal[] = $titleObj;
3419                                 }
3420                         }
3421                 }
3422                 return $retVal;
3423         }
3424
3425         /**
3426          * Get an array of Title objects using this Title as a template
3427          * Also stores the IDs in the link cache.
3428          *
3429          * WARNING: do not use this function on arbitrary user-supplied titles!
3430          * On heavily-used templates it will max out the memory.
3431          *
3432          * @param array $options Query option to Database::select()
3433          * @return Title[] Array of Title the Title objects linking here
3434          */
3435         public function getTemplateLinksTo( $options = [] ) {
3436                 return $this->getLinksTo( $options, 'templatelinks', 'tl' );
3437         }
3438
3439         /**
3440          * Get an array of Title objects linked from this Title
3441          * Also stores the IDs in the link cache.
3442          *
3443          * WARNING: do not use this function on arbitrary user-supplied titles!
3444          * On heavily-used templates it will max out the memory.
3445          *
3446          * @param array $options Query option to Database::select()
3447          * @param string $table Table name
3448          * @param string $prefix Fields prefix
3449          * @return array Array of Title objects linking here
3450          */
3451         public function getLinksFrom( $options = [], $table = 'pagelinks', $prefix = 'pl' ) {
3452                 $id = $this->getArticleID();
3453
3454                 # If the page doesn't exist; there can't be any link from this page
3455                 if ( !$id ) {
3456                         return [];
3457                 }
3458
3459                 $db = wfGetDB( DB_REPLICA );
3460
3461                 $blNamespace = "{$prefix}_namespace";
3462                 $blTitle = "{$prefix}_title";
3463
3464                 $res = $db->select(
3465                         [ $table, 'page' ],
3466                         array_merge(
3467                                 [ $blNamespace, $blTitle ],
3468                                 WikiPage::selectFields()
3469                         ),
3470                         [ "{$prefix}_from" => $id ],
3471                         __METHOD__,
3472                         $options,
3473                         [ 'page' => [
3474                                 'LEFT JOIN',
3475                                 [ "page_namespace=$blNamespace", "page_title=$blTitle" ]
3476                         ] ]
3477                 );
3478
3479                 $retVal = [];
3480                 $linkCache = LinkCache::singleton();
3481                 foreach ( $res as $row ) {
3482                         if ( $row->page_id ) {
3483                                 $titleObj = Title::newFromRow( $row );
3484                         } else {
3485                                 $titleObj = Title::makeTitle( $row->$blNamespace, $row->$blTitle );
3486                                 $linkCache->addBadLinkObj( $titleObj );
3487                         }
3488                         $retVal[] = $titleObj;
3489                 }
3490
3491                 return $retVal;
3492         }
3493
3494         /**
3495          * Get an array of Title objects used on this Title as a template
3496          * Also stores the IDs in the link cache.
3497          *
3498          * WARNING: do not use this function on arbitrary user-supplied titles!
3499          * On heavily-used templates it will max out the memory.
3500          *
3501          * @param array $options May be FOR UPDATE
3502          * @return Title[] Array of Title the Title objects used here
3503          */
3504         public function getTemplateLinksFrom( $options = [] ) {
3505                 return $this->getLinksFrom( $options, 'templatelinks', 'tl' );
3506         }
3507
3508         /**
3509          * Get an array of Title objects referring to non-existent articles linked
3510          * from this page.
3511          *
3512          * @todo check if needed (used only in SpecialBrokenRedirects.php, and
3513          *   should use redirect table in this case).
3514          * @return Title[] Array of Title the Title objects
3515          */
3516         public function getBrokenLinksFrom() {
3517                 if ( $this->getArticleID() == 0 ) {
3518                         # All links from article ID 0 are false positives
3519                         return [];
3520                 }
3521
3522                 $dbr = wfGetDB( DB_REPLICA );
3523                 $res = $dbr->select(
3524                         [ 'page', 'pagelinks' ],
3525                         [ 'pl_namespace', 'pl_title' ],
3526                         [
3527                                 'pl_from' => $this->getArticleID(),
3528                                 'page_namespace IS NULL'
3529                         ],
3530                         __METHOD__, [],
3531                         [
3532                                 'page' => [
3533                                         'LEFT JOIN',
3534                                         [ 'pl_namespace=page_namespace', 'pl_title=page_title' ]
3535                                 ]
3536                         ]
3537                 );
3538
3539                 $retVal = [];
3540                 foreach ( $res as $row ) {
3541                         $retVal[] = Title::makeTitle( $row->pl_namespace, $row->pl_title );
3542                 }
3543                 return $retVal;
3544         }
3545
3546         /**
3547          * Get a list of URLs to purge from the CDN cache when this
3548          * page changes
3549          *
3550          * @return string[] Array of String the URLs
3551          */
3552         public function getCdnUrls() {
3553                 $urls = [
3554                         $this->getInternalURL(),
3555                         $this->getInternalURL( 'action=history' )
3556                 ];
3557
3558                 $pageLang = $this->getPageLanguage();
3559                 if ( $pageLang->hasVariants() ) {
3560                         $variants = $pageLang->getVariants();
3561                         foreach ( $variants as $vCode ) {
3562                                 $urls[] = $this->getInternalURL( $vCode );
3563                         }
3564                 }
3565
3566                 // If we are looking at a css/js user subpage, purge the action=raw.
3567                 if ( $this->isJsSubpage() ) {
3568                         $urls[] = $this->getInternalURL( 'action=raw&ctype=text/javascript' );
3569                 } elseif ( $this->isCssSubpage() ) {
3570                         $urls[] = $this->getInternalURL( 'action=raw&ctype=text/css' );
3571                 }
3572
3573                 Hooks::run( 'TitleSquidURLs', [ $this, &$urls ] );
3574                 return $urls;
3575         }
3576
3577         /**
3578          * @deprecated since 1.27 use getCdnUrls()
3579          */
3580         public function getSquidURLs() {
3581                 return $this->getCdnUrls();
3582         }
3583
3584         /**
3585          * Purge all applicable CDN URLs
3586          */
3587         public function purgeSquid() {
3588                 DeferredUpdates::addUpdate(
3589                         new CdnCacheUpdate( $this->getCdnUrls() ),
3590                         DeferredUpdates::PRESEND
3591                 );
3592         }
3593
3594         /**
3595          * Check whether a given move operation would be valid.
3596          * Returns true if ok, or a getUserPermissionsErrors()-like array otherwise
3597          *
3598          * @deprecated since 1.25, use MovePage's methods instead
3599          * @param Title $nt The new title
3600          * @param bool $auth Whether to check user permissions (uses $wgUser)
3601          * @param string $reason Is the log summary of the move, used for spam checking
3602          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3603          */
3604         public function isValidMoveOperation( &$nt, $auth = true, $reason = '' ) {
3605                 global $wgUser;
3606
3607                 if ( !( $nt instanceof Title ) ) {
3608                         // Normally we'd add this to $errors, but we'll get
3609                         // lots of syntax errors if $nt is not an object
3610                         return [ [ 'badtitletext' ] ];
3611                 }
3612
3613                 $mp = new MovePage( $this, $nt );
3614                 $errors = $mp->isValidMove()->getErrorsArray();
3615                 if ( $auth ) {
3616                         $errors = wfMergeErrorArrays(
3617                                 $errors,
3618                                 $mp->checkPermissions( $wgUser, $reason )->getErrorsArray()
3619                         );
3620                 }
3621
3622                 return $errors ?: true;
3623         }
3624
3625         /**
3626          * Check if the requested move target is a valid file move target
3627          * @todo move this to MovePage
3628          * @param Title $nt Target title
3629          * @return array List of errors
3630          */
3631         protected function validateFileMoveOperation( $nt ) {
3632                 global $wgUser;
3633
3634                 $errors = [];
3635
3636                 $destFile = wfLocalFile( $nt );
3637                 $destFile->load( File::READ_LATEST );
3638                 if ( !$wgUser->isAllowed( 'reupload-shared' )
3639                         && !$destFile->exists() && wfFindFile( $nt )
3640                 ) {
3641                         $errors[] = [ 'file-exists-sharedrepo' ];
3642                 }
3643
3644                 return $errors;
3645         }
3646
3647         /**
3648          * Move a title to a new location
3649          *
3650          * @deprecated since 1.25, use the MovePage class instead
3651          * @param Title $nt The new title
3652          * @param bool $auth Indicates whether $wgUser's permissions
3653          *  should be checked
3654          * @param string $reason The reason for the move
3655          * @param bool $createRedirect Whether to create a redirect from the old title to the new title.
3656          *  Ignored if the user doesn't have the suppressredirect right.
3657          * @param array $changeTags Applied to the entry in the move log and redirect page revision
3658          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3659          */
3660         public function moveTo( &$nt, $auth = true, $reason = '', $createRedirect = true,
3661                 array $changeTags = [] ) {
3662
3663                 global $wgUser;
3664                 $err = $this->isValidMoveOperation( $nt, $auth, $reason );
3665                 if ( is_array( $err ) ) {
3666                         // Auto-block user's IP if the account was "hard" blocked
3667                         $wgUser->spreadAnyEditBlock();
3668                         return $err;
3669                 }
3670                 // Check suppressredirect permission
3671                 if ( $auth && !$wgUser->isAllowed( 'suppressredirect' ) ) {
3672                         $createRedirect = true;
3673                 }
3674
3675                 $mp = new MovePage( $this, $nt );
3676                 $status = $mp->move( $wgUser, $reason, $createRedirect, $changeTags );
3677                 if ( $status->isOK() ) {
3678                         return true;
3679                 } else {
3680                         return $status->getErrorsArray();
3681                 }
3682         }
3683
3684         /**
3685          * Move this page's subpages to be subpages of $nt
3686          *
3687          * @param Title $nt Move target
3688          * @param bool $auth Whether $wgUser's permissions should be checked
3689          * @param string $reason The reason for the move
3690          * @param bool $createRedirect Whether to create redirects from the old subpages to
3691          *     the new ones Ignored if the user doesn't have the 'suppressredirect' right
3692          * @param array $changeTags Applied to the entry in the move log and redirect page revision
3693          * @return array Array with old page titles as keys, and strings (new page titles) or
3694          *     getUserPermissionsErrors()-like arrays (errors) as values, or a
3695          *     getUserPermissionsErrors()-like error array with numeric indices if
3696          *     no pages were moved
3697          */
3698         public function moveSubpages( $nt, $auth = true, $reason = '', $createRedirect = true,
3699                 array $changeTags = [] ) {
3700
3701                 global $wgMaximumMovedPages;
3702                 // Check permissions
3703                 if ( !$this->userCan( 'move-subpages' ) ) {
3704                         return [
3705                                 [ 'cant-move-subpages' ],
3706                         ];
3707                 }
3708                 // Do the source and target namespaces support subpages?
3709                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3710                         return [
3711                                 [ 'namespace-nosubpages', MWNamespace::getCanonicalName( $this->getNamespace() ) ],
3712                         ];
3713                 }
3714                 if ( !MWNamespace::hasSubpages( $nt->getNamespace() ) ) {
3715                         return [
3716                                 [ 'namespace-nosubpages', MWNamespace::getCanonicalName( $nt->getNamespace() ) ],
3717                         ];
3718                 }
3719
3720                 $subpages = $this->getSubpages( $wgMaximumMovedPages + 1 );
3721                 $retval = [];
3722                 $count = 0;
3723                 foreach ( $subpages as $oldSubpage ) {
3724                         $count++;
3725                         if ( $count > $wgMaximumMovedPages ) {
3726                                 $retval[$oldSubpage->getPrefixedText()] = [
3727                                         [ 'movepage-max-pages', $wgMaximumMovedPages ],
3728                                 ];
3729                                 break;
3730                         }
3731
3732                         // We don't know whether this function was called before
3733                         // or after moving the root page, so check both
3734                         // $this and $nt
3735                         if ( $oldSubpage->getArticleID() == $this->getArticleID()
3736                                 || $oldSubpage->getArticleID() == $nt->getArticleID()
3737                         ) {
3738                                 // When moving a page to a subpage of itself,
3739                                 // don't move it twice
3740                                 continue;
3741                         }
3742                         $newPageName = preg_replace(
3743                                         '#^' . preg_quote( $this->getDBkey(), '#' ) . '#',
3744                                         StringUtils::escapeRegexReplacement( $nt->getDBkey() ), # T23234
3745                                         $oldSubpage->getDBkey() );
3746                         if ( $oldSubpage->isTalkPage() ) {
3747                                 $newNs = $nt->getTalkPage()->getNamespace();
3748                         } else {
3749                                 $newNs = $nt->getSubjectPage()->getNamespace();
3750                         }
3751                         # T16385: we need makeTitleSafe because the new page names may
3752                         # be longer than 255 characters.
3753                         $newSubpage = Title::makeTitleSafe( $newNs, $newPageName );
3754
3755                         $success = $oldSubpage->moveTo( $newSubpage, $auth, $reason, $createRedirect, $changeTags );
3756                         if ( $success === true ) {
3757                                 $retval[$oldSubpage->getPrefixedText()] = $newSubpage->getPrefixedText();
3758                         } else {
3759                                 $retval[$oldSubpage->getPrefixedText()] = $success;
3760                         }
3761                 }
3762                 return $retval;
3763         }
3764
3765         /**
3766          * Checks if this page is just a one-rev redirect.
3767          * Adds lock, so don't use just for light purposes.
3768          *
3769          * @return bool
3770          */
3771         public function isSingleRevRedirect() {
3772                 global $wgContentHandlerUseDB;
3773
3774                 $dbw = wfGetDB( DB_MASTER );
3775
3776                 # Is it a redirect?
3777                 $fields = [ 'page_is_redirect', 'page_latest', 'page_id' ];
3778                 if ( $wgContentHandlerUseDB ) {
3779                         $fields[] = 'page_content_model';
3780                 }
3781
3782                 $row = $dbw->selectRow( 'page',
3783                         $fields,
3784                         $this->pageCond(),
3785                         __METHOD__,
3786                         [ 'FOR UPDATE' ]
3787                 );
3788                 # Cache some fields we may want
3789                 $this->mArticleID = $row ? intval( $row->page_id ) : 0;
3790                 $this->mRedirect = $row ? (bool)$row->page_is_redirect : false;
3791                 $this->mLatestID = $row ? intval( $row->page_latest ) : false;
3792                 $this->mContentModel = $row && isset( $row->page_content_model )
3793                         ? strval( $row->page_content_model )
3794                         : false;
3795
3796                 if ( !$this->mRedirect ) {
3797                         return false;
3798                 }
3799                 # Does the article have a history?
3800                 $row = $dbw->selectField( [ 'page', 'revision' ],
3801                         'rev_id',
3802                         [ 'page_namespace' => $this->getNamespace(),
3803                                 'page_title' => $this->getDBkey(),
3804                                 'page_id=rev_page',
3805                                 'page_latest != rev_id'
3806                         ],
3807                         __METHOD__,
3808                         [ 'FOR UPDATE' ]
3809                 );
3810                 # Return true if there was no history
3811                 return ( $row === false );
3812         }
3813
3814         /**
3815          * Checks if $this can be moved to a given Title
3816          * - Selects for update, so don't call it unless you mean business
3817          *
3818          * @deprecated since 1.25, use MovePage's methods instead
3819          * @param Title $nt The new title to check
3820          * @return bool
3821          */
3822         public function isValidMoveTarget( $nt ) {
3823                 # Is it an existing file?
3824                 if ( $nt->getNamespace() == NS_FILE ) {
3825                         $file = wfLocalFile( $nt );
3826                         $file->load( File::READ_LATEST );
3827                         if ( $file->exists() ) {
3828                                 wfDebug( __METHOD__ . ": file exists\n" );
3829                                 return false;
3830                         }
3831                 }
3832                 # Is it a redirect with no history?
3833                 if ( !$nt->isSingleRevRedirect() ) {
3834                         wfDebug( __METHOD__ . ": not a one-rev redirect\n" );
3835                         return false;
3836                 }
3837                 # Get the article text
3838                 $rev = Revision::newFromTitle( $nt, false, Revision::READ_LATEST );
3839                 if ( !is_object( $rev ) ) {
3840                         return false;
3841                 }
3842                 $content = $rev->getContent();
3843                 # Does the redirect point to the source?
3844                 # Or is it a broken self-redirect, usually caused by namespace collisions?
3845                 $redirTitle = $content ? $content->getRedirectTarget() : null;
3846
3847                 if ( $redirTitle ) {
3848                         if ( $redirTitle->getPrefixedDBkey() != $this->getPrefixedDBkey() &&
3849                                 $redirTitle->getPrefixedDBkey() != $nt->getPrefixedDBkey() ) {
3850                                 wfDebug( __METHOD__ . ": redirect points to other page\n" );
3851                                 return false;
3852                         } else {
3853                                 return true;
3854                         }
3855                 } else {
3856                         # Fail safe (not a redirect after all. strange.)
3857                         wfDebug( __METHOD__ . ": failsafe: database sais " . $nt->getPrefixedDBkey() .
3858                                                 " is a redirect, but it doesn't contain a valid redirect.\n" );
3859                         return false;
3860                 }
3861         }
3862
3863         /**
3864          * Get categories to which this Title belongs and return an array of
3865          * categories' names.
3866          *
3867          * @return array Array of parents in the form:
3868          *        $parent => $currentarticle
3869          */
3870         public function getParentCategories() {
3871                 global $wgContLang;
3872
3873                 $data = [];
3874
3875                 $titleKey = $this->getArticleID();
3876
3877                 if ( $titleKey === 0 ) {
3878                         return $data;
3879                 }
3880
3881                 $dbr = wfGetDB( DB_REPLICA );
3882
3883                 $res = $dbr->select(
3884                         'categorylinks',
3885                         'cl_to',
3886                         [ 'cl_from' => $titleKey ],
3887                         __METHOD__
3888                 );
3889
3890                 if ( $res->numRows() > 0 ) {
3891                         foreach ( $res as $row ) {
3892                                 // $data[] = Title::newFromText($wgContLang->getNsText ( NS_CATEGORY ).':'.$row->cl_to);
3893                                 $data[$wgContLang->getNsText( NS_CATEGORY ) . ':' . $row->cl_to] = $this->getFullText();
3894                         }
3895                 }
3896                 return $data;
3897         }
3898
3899         /**
3900          * Get a tree of parent categories
3901          *
3902          * @param array $children Array with the children in the keys, to check for circular refs
3903          * @return array Tree of parent categories
3904          */
3905         public function getParentCategoryTree( $children = [] ) {
3906                 $stack = [];
3907                 $parents = $this->getParentCategories();
3908
3909                 if ( $parents ) {
3910                         foreach ( $parents as $parent => $current ) {
3911                                 if ( array_key_exists( $parent, $children ) ) {
3912                                         # Circular reference
3913                                         $stack[$parent] = [];
3914                                 } else {
3915                                         $nt = Title::newFromText( $parent );
3916                                         if ( $nt ) {
3917                                                 $stack[$parent] = $nt->getParentCategoryTree( $children + [ $parent => 1 ] );
3918                                         }
3919                                 }
3920                         }
3921                 }
3922
3923                 return $stack;
3924         }
3925
3926         /**
3927          * Get an associative array for selecting this title from
3928          * the "page" table
3929          *
3930          * @return array Array suitable for the $where parameter of DB::select()
3931          */
3932         public function pageCond() {
3933                 if ( $this->mArticleID > 0 ) {
3934                         // PK avoids secondary lookups in InnoDB, shouldn't hurt other DBs
3935                         return [ 'page_id' => $this->mArticleID ];
3936                 } else {
3937                         return [ 'page_namespace' => $this->mNamespace, 'page_title' => $this->mDbkeyform ];
3938                 }
3939         }
3940
3941         /**
3942          * Get the revision ID of the previous revision
3943          *
3944          * @param int $revId Revision ID. Get the revision that was before this one.
3945          * @param int $flags Title::GAID_FOR_UPDATE
3946          * @return int|bool Old revision ID, or false if none exists
3947          */
3948         public function getPreviousRevisionID( $revId, $flags = 0 ) {
3949                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_REPLICA );
3950                 $revId = $db->selectField( 'revision', 'rev_id',
3951                         [
3952                                 'rev_page' => $this->getArticleID( $flags ),
3953                                 'rev_id < ' . intval( $revId )
3954                         ],
3955                         __METHOD__,
3956                         [ 'ORDER BY' => 'rev_id DESC' ]
3957                 );
3958
3959                 if ( $revId === false ) {
3960                         return false;
3961                 } else {
3962                         return intval( $revId );
3963                 }
3964         }
3965
3966         /**
3967          * Get the revision ID of the next revision
3968          *
3969          * @param int $revId Revision ID. Get the revision that was after this one.
3970          * @param int $flags Title::GAID_FOR_UPDATE
3971          * @return int|bool Next revision ID, or false if none exists
3972          */
3973         public function getNextRevisionID( $revId, $flags = 0 ) {
3974                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_REPLICA );
3975                 $revId = $db->selectField( 'revision', 'rev_id',
3976                         [
3977                                 'rev_page' => $this->getArticleID( $flags ),
3978                                 'rev_id > ' . intval( $revId )
3979                         ],
3980                         __METHOD__,
3981                         [ 'ORDER BY' => 'rev_id' ]
3982                 );
3983
3984                 if ( $revId === false ) {
3985                         return false;
3986                 } else {
3987                         return intval( $revId );
3988                 }
3989         }
3990
3991         /**
3992          * Get the first revision of the page
3993          *
3994          * @param int $flags Title::GAID_FOR_UPDATE
3995          * @return Revision|null If page doesn't exist
3996          */
3997         public function getFirstRevision( $flags = 0 ) {
3998                 $pageId = $this->getArticleID( $flags );
3999                 if ( $pageId ) {
4000                         $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_REPLICA );
4001                         $row = $db->selectRow( 'revision', Revision::selectFields(),
4002                                 [ 'rev_page' => $pageId ],
4003                                 __METHOD__,
4004                                 [ 'ORDER BY' => 'rev_timestamp ASC', 'LIMIT' => 1 ]
4005                         );
4006                         if ( $row ) {
4007                                 return new Revision( $row );
4008                         }
4009                 }
4010                 return null;
4011         }
4012
4013         /**
4014          * Get the oldest revision timestamp of this page
4015          *
4016          * @param int $flags Title::GAID_FOR_UPDATE
4017          * @return string MW timestamp
4018          */
4019         public function getEarliestRevTime( $flags = 0 ) {
4020                 $rev = $this->getFirstRevision( $flags );
4021                 return $rev ? $rev->getTimestamp() : null;
4022         }
4023
4024         /**
4025          * Check if this is a new page
4026          *
4027          * @return bool
4028          */
4029         public function isNewPage() {
4030                 $dbr = wfGetDB( DB_REPLICA );
4031                 return (bool)$dbr->selectField( 'page', 'page_is_new', $this->pageCond(), __METHOD__ );
4032         }
4033
4034         /**
4035          * Check whether the number of revisions of this page surpasses $wgDeleteRevisionsLimit
4036          *
4037          * @return bool
4038          */
4039         public function isBigDeletion() {
4040                 global $wgDeleteRevisionsLimit;
4041
4042                 if ( !$wgDeleteRevisionsLimit ) {
4043                         return false;
4044                 }
4045
4046                 if ( $this->mIsBigDeletion === null ) {
4047                         $dbr = wfGetDB( DB_REPLICA );
4048
4049                         $revCount = $dbr->selectRowCount(
4050                                 'revision',
4051                                 '1',
4052                                 [ 'rev_page' => $this->getArticleID() ],
4053                                 __METHOD__,
4054                                 [ 'LIMIT' => $wgDeleteRevisionsLimit + 1 ]
4055                         );
4056
4057                         $this->mIsBigDeletion = $revCount > $wgDeleteRevisionsLimit;
4058                 }
4059
4060                 return $this->mIsBigDeletion;
4061         }
4062
4063         /**
4064          * Get the approximate revision count of this page.
4065          *
4066          * @return int
4067          */
4068         public function estimateRevisionCount() {
4069                 if ( !$this->exists() ) {
4070                         return 0;
4071                 }
4072
4073                 if ( $this->mEstimateRevisions === null ) {
4074                         $dbr = wfGetDB( DB_REPLICA );
4075                         $this->mEstimateRevisions = $dbr->estimateRowCount( 'revision', '*',
4076                                 [ 'rev_page' => $this->getArticleID() ], __METHOD__ );
4077                 }
4078
4079                 return $this->mEstimateRevisions;
4080         }
4081
4082         /**
4083          * Get the number of revisions between the given revision.
4084          * Used for diffs and other things that really need it.
4085          *
4086          * @param int|Revision $old Old revision or rev ID (first before range)
4087          * @param int|Revision $new New revision or rev ID (first after range)
4088          * @param int|null $max Limit of Revisions to count, will be incremented to detect truncations
4089          * @return int Number of revisions between these revisions.
4090          */
4091         public function countRevisionsBetween( $old, $new, $max = null ) {
4092                 if ( !( $old instanceof Revision ) ) {
4093                         $old = Revision::newFromTitle( $this, (int)$old );
4094                 }
4095                 if ( !( $new instanceof Revision ) ) {
4096                         $new = Revision::newFromTitle( $this, (int)$new );
4097                 }
4098                 if ( !$old || !$new ) {
4099                         return 0; // nothing to compare
4100                 }
4101                 $dbr = wfGetDB( DB_REPLICA );
4102                 $conds = [
4103                         'rev_page' => $this->getArticleID(),
4104                         'rev_timestamp > ' . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4105                         'rev_timestamp < ' . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4106                 ];
4107                 if ( $max !== null ) {
4108                         return $dbr->selectRowCount( 'revision', '1',
4109                                 $conds,
4110                                 __METHOD__,
4111                                 [ 'LIMIT' => $max + 1 ] // extra to detect truncation
4112                         );
4113                 } else {
4114                         return (int)$dbr->selectField( 'revision', 'count(*)', $conds, __METHOD__ );
4115                 }
4116         }
4117
4118         /**
4119          * Get the authors between the given revisions or revision IDs.
4120          * Used for diffs and other things that really need it.
4121          *
4122          * @since 1.23
4123          *
4124          * @param int|Revision $old Old revision or rev ID (first before range by default)
4125          * @param int|Revision $new New revision or rev ID (first after range by default)
4126          * @param int $limit Maximum number of authors
4127          * @param string|array $options (Optional): Single option, or an array of options:
4128          *     'include_old' Include $old in the range; $new is excluded.
4129          *     'include_new' Include $new in the range; $old is excluded.
4130          *     'include_both' Include both $old and $new in the range.
4131          *     Unknown option values are ignored.
4132          * @return array|null Names of revision authors in the range; null if not both revisions exist
4133          */
4134         public function getAuthorsBetween( $old, $new, $limit, $options = [] ) {
4135                 if ( !( $old instanceof Revision ) ) {
4136                         $old = Revision::newFromTitle( $this, (int)$old );
4137                 }
4138                 if ( !( $new instanceof Revision ) ) {
4139                         $new = Revision::newFromTitle( $this, (int)$new );
4140                 }
4141                 // XXX: what if Revision objects are passed in, but they don't refer to this title?
4142                 // Add $old->getPage() != $new->getPage() || $old->getPage() != $this->getArticleID()
4143                 // in the sanity check below?
4144                 if ( !$old || !$new ) {
4145                         return null; // nothing to compare
4146                 }
4147                 $authors = [];
4148                 $old_cmp = '>';
4149                 $new_cmp = '<';
4150                 $options = (array)$options;
4151                 if ( in_array( 'include_old', $options ) ) {
4152                         $old_cmp = '>=';
4153                 }
4154                 if ( in_array( 'include_new', $options ) ) {
4155                         $new_cmp = '<=';
4156                 }
4157                 if ( in_array( 'include_both', $options ) ) {
4158                         $old_cmp = '>=';
4159                         $new_cmp = '<=';
4160                 }
4161                 // No DB query needed if $old and $new are the same or successive revisions:
4162                 if ( $old->getId() === $new->getId() ) {
4163                         return ( $old_cmp === '>' && $new_cmp === '<' ) ?
4164                                 [] :
4165                                 [ $old->getUserText( Revision::RAW ) ];
4166                 } elseif ( $old->getId() === $new->getParentId() ) {
4167                         if ( $old_cmp === '>=' && $new_cmp === '<=' ) {
4168                                 $authors[] = $old->getUserText( Revision::RAW );
4169                                 if ( $old->getUserText( Revision::RAW ) != $new->getUserText( Revision::RAW ) ) {
4170                                         $authors[] = $new->getUserText( Revision::RAW );
4171                                 }
4172                         } elseif ( $old_cmp === '>=' ) {
4173                                 $authors[] = $old->getUserText( Revision::RAW );
4174                         } elseif ( $new_cmp === '<=' ) {
4175                                 $authors[] = $new->getUserText( Revision::RAW );
4176                         }
4177                         return $authors;
4178                 }
4179                 $dbr = wfGetDB( DB_REPLICA );
4180                 $res = $dbr->select( 'revision', 'DISTINCT rev_user_text',
4181                         [
4182                                 'rev_page' => $this->getArticleID(),
4183                                 "rev_timestamp $old_cmp " . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4184                                 "rev_timestamp $new_cmp " . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4185                         ], __METHOD__,
4186                         [ 'LIMIT' => $limit + 1 ] // add one so caller knows it was truncated
4187                 );
4188                 foreach ( $res as $row ) {
4189                         $authors[] = $row->rev_user_text;
4190                 }
4191                 return $authors;
4192         }
4193
4194         /**
4195          * Get the number of authors between the given revisions or revision IDs.
4196          * Used for diffs and other things that really need it.
4197          *
4198          * @param int|Revision $old Old revision or rev ID (first before range by default)
4199          * @param int|Revision $new New revision or rev ID (first after range by default)
4200          * @param int $limit Maximum number of authors
4201          * @param string|array $options (Optional): Single option, or an array of options:
4202          *     'include_old' Include $old in the range; $new is excluded.
4203          *     'include_new' Include $new in the range; $old is excluded.
4204          *     'include_both' Include both $old and $new in the range.
4205          *     Unknown option values are ignored.
4206          * @return int Number of revision authors in the range; zero if not both revisions exist
4207          */
4208         public function countAuthorsBetween( $old, $new, $limit, $options = [] ) {
4209                 $authors = $this->getAuthorsBetween( $old, $new, $limit, $options );
4210                 return $authors ? count( $authors ) : 0;
4211         }
4212
4213         /**
4214          * Compare with another title.
4215          *
4216          * @param Title $title
4217          * @return bool
4218          */
4219         public function equals( Title $title ) {
4220                 // Note: === is necessary for proper matching of number-like titles.
4221                 return $this->getInterwiki() === $title->getInterwiki()
4222                         && $this->getNamespace() == $title->getNamespace()
4223                         && $this->getDBkey() === $title->getDBkey();
4224         }
4225
4226         /**
4227          * Check if this title is a subpage of another title
4228          *
4229          * @param Title $title
4230          * @return bool
4231          */
4232         public function isSubpageOf( Title $title ) {
4233                 return $this->getInterwiki() === $title->getInterwiki()
4234                         && $this->getNamespace() == $title->getNamespace()
4235                         && strpos( $this->getDBkey(), $title->getDBkey() . '/' ) === 0;
4236         }
4237
4238         /**
4239          * Check if page exists.  For historical reasons, this function simply
4240          * checks for the existence of the title in the page table, and will
4241          * thus return false for interwiki links, special pages and the like.
4242          * If you want to know if a title can be meaningfully viewed, you should
4243          * probably call the isKnown() method instead.
4244          *
4245          * @param int $flags An optional bit field; may be Title::GAID_FOR_UPDATE to check
4246          *   from master/for update
4247          * @return bool
4248          */
4249         public function exists( $flags = 0 ) {
4250                 $exists = $this->getArticleID( $flags ) != 0;
4251                 Hooks::run( 'TitleExists', [ $this, &$exists ] );
4252                 return $exists;
4253         }
4254
4255         /**
4256          * Should links to this title be shown as potentially viewable (i.e. as
4257          * "bluelinks"), even if there's no record by this title in the page
4258          * table?
4259          *
4260          * This function is semi-deprecated for public use, as well as somewhat
4261          * misleadingly named.  You probably just want to call isKnown(), which
4262          * calls this function internally.
4263          *
4264          * (ISSUE: Most of these checks are cheap, but the file existence check
4265          * can potentially be quite expensive.  Including it here fixes a lot of
4266          * existing code, but we might want to add an optional parameter to skip
4267          * it and any other expensive checks.)
4268          *
4269          * @return bool
4270          */
4271         public function isAlwaysKnown() {
4272                 $isKnown = null;
4273
4274                 /**
4275                  * Allows overriding default behavior for determining if a page exists.
4276                  * If $isKnown is kept as null, regular checks happen. If it's
4277                  * a boolean, this value is returned by the isKnown method.
4278                  *
4279                  * @since 1.20
4280                  *
4281                  * @param Title $title
4282                  * @param bool|null $isKnown
4283                  */
4284                 Hooks::run( 'TitleIsAlwaysKnown', [ $this, &$isKnown ] );
4285
4286                 if ( !is_null( $isKnown ) ) {
4287                         return $isKnown;
4288                 }
4289
4290                 if ( $this->isExternal() ) {
4291                         return true;  // any interwiki link might be viewable, for all we know
4292                 }
4293
4294                 switch ( $this->mNamespace ) {
4295                         case NS_MEDIA:
4296                         case NS_FILE:
4297                                 // file exists, possibly in a foreign repo
4298                                 return (bool)wfFindFile( $this );
4299                         case NS_SPECIAL:
4300                                 // valid special page
4301                                 return SpecialPageFactory::exists( $this->getDBkey() );
4302                         case NS_MAIN:
4303                                 // selflink, possibly with fragment
4304                                 return $this->mDbkeyform == '';
4305                         case NS_MEDIAWIKI:
4306                                 // known system message
4307                                 return $this->hasSourceText() !== false;
4308                         default:
4309                                 return false;
4310                 }
4311         }
4312
4313         /**
4314          * Does this title refer to a page that can (or might) be meaningfully
4315          * viewed?  In particular, this function may be used to determine if
4316          * links to the title should be rendered as "bluelinks" (as opposed to
4317          * "redlinks" to non-existent pages).
4318          * Adding something else to this function will cause inconsistency
4319          * since LinkHolderArray calls isAlwaysKnown() and does its own
4320          * page existence check.
4321          *
4322          * @return bool
4323          */
4324         public function isKnown() {
4325                 return $this->isAlwaysKnown() || $this->exists();
4326         }
4327
4328         /**
4329          * Does this page have source text?
4330          *
4331          * @return bool
4332          */
4333         public function hasSourceText() {
4334                 if ( $this->exists() ) {
4335                         return true;
4336                 }
4337
4338                 if ( $this->mNamespace == NS_MEDIAWIKI ) {
4339                         // If the page doesn't exist but is a known system message, default
4340                         // message content will be displayed, same for language subpages-
4341                         // Use always content language to avoid loading hundreds of languages
4342                         // to get the link color.
4343                         global $wgContLang;
4344                         list( $name, ) = MessageCache::singleton()->figureMessage(
4345                                 $wgContLang->lcfirst( $this->getText() )
4346                         );
4347                         $message = wfMessage( $name )->inLanguage( $wgContLang )->useDatabase( false );
4348                         return $message->exists();
4349                 }
4350
4351                 return false;
4352         }
4353
4354         /**
4355          * Get the default message text or false if the message doesn't exist
4356          *
4357          * @return string|bool
4358          */
4359         public function getDefaultMessageText() {
4360                 global $wgContLang;
4361
4362                 if ( $this->getNamespace() != NS_MEDIAWIKI ) { // Just in case
4363                         return false;
4364                 }
4365
4366                 list( $name, $lang ) = MessageCache::singleton()->figureMessage(
4367                         $wgContLang->lcfirst( $this->getText() )
4368                 );
4369                 $message = wfMessage( $name )->inLanguage( $lang )->useDatabase( false );
4370
4371                 if ( $message->exists() ) {
4372                         return $message->plain();
4373                 } else {
4374                         return false;
4375                 }
4376         }
4377
4378         /**
4379          * Updates page_touched for this page; called from LinksUpdate.php
4380          *
4381          * @param string $purgeTime [optional] TS_MW timestamp
4382          * @return bool True if the update succeeded
4383          */
4384         public function invalidateCache( $purgeTime = null ) {
4385                 if ( wfReadOnly() ) {
4386                         return false;
4387                 } elseif ( $this->mArticleID === 0 ) {
4388                         return true; // avoid gap locking if we know it's not there
4389                 }
4390
4391                 $dbw = wfGetDB( DB_MASTER );
4392                 $dbw->onTransactionPreCommitOrIdle( function () {
4393                         ResourceLoaderWikiModule::invalidateModuleCache( $this, null, null, wfWikiID() );
4394                 } );
4395
4396                 $conds = $this->pageCond();
4397                 DeferredUpdates::addUpdate(
4398                         new AutoCommitUpdate(
4399                                 $dbw,
4400                                 __METHOD__,
4401                                 function ( IDatabase $dbw, $fname ) use ( $conds, $purgeTime ) {
4402                                         $dbTimestamp = $dbw->timestamp( $purgeTime ?: time() );
4403                                         $dbw->update(
4404                                                 'page',
4405                                                 [ 'page_touched' => $dbTimestamp ],
4406                                                 $conds + [ 'page_touched < ' . $dbw->addQuotes( $dbTimestamp ) ],
4407                                                 $fname
4408                                         );
4409                                         MediaWikiServices::getInstance()->getLinkCache()->invalidateTitle( $this );
4410                                 }
4411                         ),
4412                         DeferredUpdates::PRESEND
4413                 );
4414
4415                 return true;
4416         }
4417
4418         /**
4419          * Update page_touched timestamps and send CDN purge messages for
4420          * pages linking to this title. May be sent to the job queue depending
4421          * on the number of links. Typically called on create and delete.
4422          */
4423         public function touchLinks() {
4424                 DeferredUpdates::addUpdate( new HTMLCacheUpdate( $this, 'pagelinks' ) );
4425                 if ( $this->getNamespace() == NS_CATEGORY ) {
4426                         DeferredUpdates::addUpdate( new HTMLCacheUpdate( $this, 'categorylinks' ) );
4427                 }
4428         }
4429
4430         /**
4431          * Get the last touched timestamp
4432          *
4433          * @param IDatabase $db Optional db
4434          * @return string|false Last-touched timestamp
4435          */
4436         public function getTouched( $db = null ) {
4437                 if ( $db === null ) {
4438                         $db = wfGetDB( DB_REPLICA );
4439                 }
4440                 $touched = $db->selectField( 'page', 'page_touched', $this->pageCond(), __METHOD__ );
4441                 return $touched;
4442         }
4443
4444         /**
4445          * Get the timestamp when this page was updated since the user last saw it.
4446          *
4447          * @param User $user
4448          * @return string|null
4449          */
4450         public function getNotificationTimestamp( $user = null ) {
4451                 global $wgUser;
4452
4453                 // Assume current user if none given
4454                 if ( !$user ) {
4455                         $user = $wgUser;
4456                 }
4457                 // Check cache first
4458                 $uid = $user->getId();
4459                 if ( !$uid ) {
4460                         return false;
4461                 }
4462                 // avoid isset here, as it'll return false for null entries
4463                 if ( array_key_exists( $uid, $this->mNotificationTimestamp ) ) {
4464                         return $this->mNotificationTimestamp[$uid];
4465                 }
4466                 // Don't cache too much!
4467                 if ( count( $this->mNotificationTimestamp ) >= self::CACHE_MAX ) {
4468                         $this->mNotificationTimestamp = [];
4469                 }
4470
4471                 $store = MediaWikiServices::getInstance()->getWatchedItemStore();
4472                 $watchedItem = $store->getWatchedItem( $user, $this );
4473                 if ( $watchedItem ) {
4474                         $this->mNotificationTimestamp[$uid] = $watchedItem->getNotificationTimestamp();
4475                 } else {
4476                         $this->mNotificationTimestamp[$uid] = false;
4477                 }
4478
4479                 return $this->mNotificationTimestamp[$uid];
4480         }
4481
4482         /**
4483          * Generate strings used for xml 'id' names in monobook tabs
4484          *
4485          * @param string $prepend Defaults to 'nstab-'
4486          * @return string XML 'id' name
4487          */
4488         public function getNamespaceKey( $prepend = 'nstab-' ) {
4489                 global $wgContLang;
4490                 // Gets the subject namespace if this title
4491                 $namespace = MWNamespace::getSubject( $this->getNamespace() );
4492                 // Checks if canonical namespace name exists for namespace
4493                 if ( MWNamespace::exists( $this->getNamespace() ) ) {
4494                         // Uses canonical namespace name
4495                         $namespaceKey = MWNamespace::getCanonicalName( $namespace );
4496                 } else {
4497                         // Uses text of namespace
4498                         $namespaceKey = $this->getSubjectNsText();
4499                 }
4500                 // Makes namespace key lowercase
4501                 $namespaceKey = $wgContLang->lc( $namespaceKey );
4502                 // Uses main
4503                 if ( $namespaceKey == '' ) {
4504                         $namespaceKey = 'main';
4505                 }
4506                 // Changes file to image for backwards compatibility
4507                 if ( $namespaceKey == 'file' ) {
4508                         $namespaceKey = 'image';
4509                 }
4510                 return $prepend . $namespaceKey;
4511         }
4512
4513         /**
4514          * Get all extant redirects to this Title
4515          *
4516          * @param int|null $ns Single namespace to consider; null to consider all namespaces
4517          * @return Title[] Array of Title redirects to this title
4518          */
4519         public function getRedirectsHere( $ns = null ) {
4520                 $redirs = [];
4521
4522                 $dbr = wfGetDB( DB_REPLICA );
4523                 $where = [
4524                         'rd_namespace' => $this->getNamespace(),
4525                         'rd_title' => $this->getDBkey(),
4526                         'rd_from = page_id'
4527                 ];
4528                 if ( $this->isExternal() ) {
4529                         $where['rd_interwiki'] = $this->getInterwiki();
4530                 } else {
4531                         $where[] = 'rd_interwiki = ' . $dbr->addQuotes( '' ) . ' OR rd_interwiki IS NULL';
4532                 }
4533                 if ( !is_null( $ns ) ) {
4534                         $where['page_namespace'] = $ns;
4535                 }
4536
4537                 $res = $dbr->select(
4538                         [ 'redirect', 'page' ],
4539                         [ 'page_namespace', 'page_title' ],
4540                         $where,
4541                         __METHOD__
4542                 );
4543
4544                 foreach ( $res as $row ) {
4545                         $redirs[] = self::newFromRow( $row );
4546                 }
4547                 return $redirs;
4548         }
4549
4550         /**
4551          * Check if this Title is a valid redirect target
4552          *
4553          * @return bool
4554          */
4555         public function isValidRedirectTarget() {
4556                 global $wgInvalidRedirectTargets;
4557
4558                 if ( $this->isSpecialPage() ) {
4559                         // invalid redirect targets are stored in a global array, but explicitly disallow Userlogout here
4560                         if ( $this->isSpecial( 'Userlogout' ) ) {
4561                                 return false;
4562                         }
4563
4564                         foreach ( $wgInvalidRedirectTargets as $target ) {
4565                                 if ( $this->isSpecial( $target ) ) {
4566                                         return false;
4567                                 }
4568                         }
4569                 }
4570
4571                 return true;
4572         }
4573
4574         /**
4575          * Get a backlink cache object
4576          *
4577          * @return BacklinkCache
4578          */
4579         public function getBacklinkCache() {
4580                 return BacklinkCache::get( $this );
4581         }
4582
4583         /**
4584          * Whether the magic words __INDEX__ and __NOINDEX__ function for  this page.
4585          *
4586          * @return bool
4587          */
4588         public function canUseNoindex() {
4589                 global $wgExemptFromUserRobotsControl;
4590
4591                 $bannedNamespaces = is_null( $wgExemptFromUserRobotsControl )
4592                         ? MWNamespace::getContentNamespaces()
4593                         : $wgExemptFromUserRobotsControl;
4594
4595                 return !in_array( $this->mNamespace, $bannedNamespaces );
4596         }
4597
4598         /**
4599          * Returns the raw sort key to be used for categories, with the specified
4600          * prefix.  This will be fed to Collation::getSortKey() to get a
4601          * binary sortkey that can be used for actual sorting.
4602          *
4603          * @param string $prefix The prefix to be used, specified using
4604          *   {{defaultsort:}} or like [[Category:Foo|prefix]].  Empty for no
4605          *   prefix.
4606          * @return string
4607          */
4608         public function getCategorySortkey( $prefix = '' ) {
4609                 $unprefixed = $this->getText();
4610
4611                 // Anything that uses this hook should only depend
4612                 // on the Title object passed in, and should probably
4613                 // tell the users to run updateCollations.php --force
4614                 // in order to re-sort existing category relations.
4615                 Hooks::run( 'GetDefaultSortkey', [ $this, &$unprefixed ] );
4616                 if ( $prefix !== '' ) {
4617                         # Separate with a line feed, so the unprefixed part is only used as
4618                         # a tiebreaker when two pages have the exact same prefix.
4619                         # In UCA, tab is the only character that can sort above LF
4620                         # so we strip both of them from the original prefix.
4621                         $prefix = strtr( $prefix, "\n\t", '  ' );
4622                         return "$prefix\n$unprefixed";
4623                 }
4624                 return $unprefixed;
4625         }
4626
4627         /**
4628          * Returns the page language code saved in the database, if $wgPageLanguageUseDB is set
4629          * to true in LocalSettings.php, otherwise returns false. If there is no language saved in
4630          * the db, it will return NULL.
4631          *
4632          * @return string|null|bool
4633          */
4634         private function getDbPageLanguageCode() {
4635                 global $wgPageLanguageUseDB;
4636
4637                 // check, if the page language could be saved in the database, and if so and
4638                 // the value is not requested already, lookup the page language using LinkCache
4639                 if ( $wgPageLanguageUseDB && $this->mDbPageLanguage === false ) {
4640                         $linkCache = LinkCache::singleton();
4641                         $linkCache->addLinkObj( $this );
4642                         $this->mDbPageLanguage = $linkCache->getGoodLinkFieldObj( $this, 'lang' );
4643                 }
4644
4645                 return $this->mDbPageLanguage;
4646         }
4647
4648         /**
4649          * Get the language in which the content of this page is written in
4650          * wikitext. Defaults to $wgContLang, but in certain cases it can be
4651          * e.g. $wgLang (such as special pages, which are in the user language).
4652          *
4653          * @since 1.18
4654          * @return Language
4655          */
4656         public function getPageLanguage() {
4657                 global $wgLang, $wgLanguageCode;
4658                 if ( $this->isSpecialPage() ) {
4659                         // special pages are in the user language
4660                         return $wgLang;
4661                 }
4662
4663                 // Checking if DB language is set
4664                 $dbPageLanguage = $this->getDbPageLanguageCode();
4665                 if ( $dbPageLanguage ) {
4666                         return wfGetLangObj( $dbPageLanguage );
4667                 }
4668
4669                 if ( !$this->mPageLanguage || $this->mPageLanguage[1] !== $wgLanguageCode ) {
4670                         // Note that this may depend on user settings, so the cache should
4671                         // be only per-request.
4672                         // NOTE: ContentHandler::getPageLanguage() may need to load the
4673                         // content to determine the page language!
4674                         // Checking $wgLanguageCode hasn't changed for the benefit of unit
4675                         // tests.
4676                         $contentHandler = ContentHandler::getForTitle( $this );
4677                         $langObj = $contentHandler->getPageLanguage( $this );
4678                         $this->mPageLanguage = [ $langObj->getCode(), $wgLanguageCode ];
4679                 } else {
4680                         $langObj = wfGetLangObj( $this->mPageLanguage[0] );
4681                 }
4682
4683                 return $langObj;
4684         }
4685
4686         /**
4687          * Get the language in which the content of this page is written when
4688          * viewed by user. Defaults to $wgContLang, but in certain cases it can be
4689          * e.g. $wgLang (such as special pages, which are in the user language).
4690          *
4691          * @since 1.20
4692          * @return Language
4693          */
4694         public function getPageViewLanguage() {
4695                 global $wgLang;
4696
4697                 if ( $this->isSpecialPage() ) {
4698                         // If the user chooses a variant, the content is actually
4699                         // in a language whose code is the variant code.
4700                         $variant = $wgLang->getPreferredVariant();
4701                         if ( $wgLang->getCode() !== $variant ) {
4702                                 return Language::factory( $variant );
4703                         }
4704
4705                         return $wgLang;
4706                 }
4707
4708                 // Checking if DB language is set
4709                 $dbPageLanguage = $this->getDbPageLanguageCode();
4710                 if ( $dbPageLanguage ) {
4711                         $pageLang = wfGetLangObj( $dbPageLanguage );
4712                         $variant = $pageLang->getPreferredVariant();
4713                         if ( $pageLang->getCode() !== $variant ) {
4714                                 $pageLang = Language::factory( $variant );
4715                         }
4716
4717                         return $pageLang;
4718                 }
4719
4720                 // @note Can't be cached persistently, depends on user settings.
4721                 // @note ContentHandler::getPageViewLanguage() may need to load the
4722                 //   content to determine the page language!
4723                 $contentHandler = ContentHandler::getForTitle( $this );
4724                 $pageLang = $contentHandler->getPageViewLanguage( $this );
4725                 return $pageLang;
4726         }
4727
4728         /**
4729          * Get a list of rendered edit notices for this page.
4730          *
4731          * Array is keyed by the original message key, and values are rendered using parseAsBlock, so
4732          * they will already be wrapped in paragraphs.
4733          *
4734          * @since 1.21
4735          * @param int $oldid Revision ID that's being edited
4736          * @return array
4737          */
4738         public function getEditNotices( $oldid = 0 ) {
4739                 $notices = [];
4740
4741                 // Optional notice for the entire namespace
4742                 $editnotice_ns = 'editnotice-' . $this->getNamespace();
4743                 $msg = wfMessage( $editnotice_ns );
4744                 if ( $msg->exists() ) {
4745                         $html = $msg->parseAsBlock();
4746                         // Edit notices may have complex logic, but output nothing (T91715)
4747                         if ( trim( $html ) !== '' ) {
4748                                 $notices[$editnotice_ns] = Html::rawElement(
4749                                         'div',
4750                                         [ 'class' => [
4751                                                 'mw-editnotice',
4752                                                 'mw-editnotice-namespace',
4753                                                 Sanitizer::escapeClass( "mw-$editnotice_ns" )
4754                                         ] ],
4755                                         $html
4756                                 );
4757                         }
4758                 }
4759
4760                 if ( MWNamespace::hasSubpages( $this->getNamespace() ) ) {
4761                         // Optional notice for page itself and any parent page
4762                         $parts = explode( '/', $this->getDBkey() );
4763                         $editnotice_base = $editnotice_ns;
4764                         while ( count( $parts ) > 0 ) {
4765                                 $editnotice_base .= '-' . array_shift( $parts );
4766                                 $msg = wfMessage( $editnotice_base );
4767                                 if ( $msg->exists() ) {
4768                                         $html = $msg->parseAsBlock();
4769                                         if ( trim( $html ) !== '' ) {
4770                                                 $notices[$editnotice_base] = Html::rawElement(
4771                                                         'div',
4772                                                         [ 'class' => [
4773                                                                 'mw-editnotice',
4774                                                                 'mw-editnotice-base',
4775                                                                 Sanitizer::escapeClass( "mw-$editnotice_base" )
4776                                                         ] ],
4777                                                         $html
4778                                                 );
4779                                         }
4780                                 }
4781                         }
4782                 } else {
4783                         // Even if there are no subpages in namespace, we still don't want "/" in MediaWiki message keys
4784                         $editnoticeText = $editnotice_ns . '-' . strtr( $this->getDBkey(), '/', '-' );
4785                         $msg = wfMessage( $editnoticeText );
4786                         if ( $msg->exists() ) {
4787                                 $html = $msg->parseAsBlock();
4788                                 if ( trim( $html ) !== '' ) {
4789                                         $notices[$editnoticeText] = Html::rawElement(
4790                                                 'div',
4791                                                 [ 'class' => [
4792                                                         'mw-editnotice',
4793                                                         'mw-editnotice-page',
4794                                                         Sanitizer::escapeClass( "mw-$editnoticeText" )
4795                                                 ] ],
4796                                                 $html
4797                                         );
4798                                 }
4799                         }
4800                 }
4801
4802                 Hooks::run( 'TitleGetEditNotices', [ $this, $oldid, &$notices ] );
4803                 return $notices;
4804         }
4805
4806         /**
4807          * @return array
4808          */
4809         public function __sleep() {
4810                 return [
4811                         'mNamespace',
4812                         'mDbkeyform',
4813                         'mFragment',
4814                         'mInterwiki',
4815                         'mLocalInterwiki',
4816                         'mUserCaseDBKey',
4817                         'mDefaultNamespace',
4818                 ];
4819         }
4820
4821         public function __wakeup() {
4822                 $this->mArticleID = ( $this->mNamespace >= 0 ) ? -1 : 0;
4823                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
4824                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
4825         }
4826
4827 }