includes/Title.php

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