includes/Title.php

   1 <?php
   2 /**
   3  * Representation of a title within %MediaWiki.
   4  *
   5  * See title.txt
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License along
  18  * with this program; if not, write to the Free Software Foundation, Inc.,
  19  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  20  * http://www.gnu.org/copyleft/gpl.html
  21  *
  22  * @file
  23  */
  24
  25 use Wikimedia\Rdbms\Database;
  26 use Wikimedia\Rdbms\IDatabase;
  27 use MediaWiki\Linker\LinkTarget;
  28 use MediaWiki\Interwiki\InterwikiLookup;
  29 use MediaWiki\MediaWikiServices;
  30
  31 /**
  32  * Represents a title within MediaWiki.
  33  * Optionally may contain an interwiki designation or namespace.
  34  * @note This class can fetch various kinds of data from the database;
  35  *       however, it does so inefficiently.
  36  * @note Consider using a TitleValue object instead. TitleValue is more lightweight
  37  *       and does not rely on global state or the database.
  38  */
  39 class Title implements LinkTarget {
  40         /** @var HashBagOStuff */
  41         static private $titleCache = null;
  42
  43         /**
  44          * Title::newFromText maintains a cache to avoid expensive re-normalization of
  45          * commonly used titles. On a batch operation this can become a memory leak
  46          * if not bounded. After hitting this many titles reset the cache.
  47          */
  48         const CACHE_MAX = 1000;
  49
  50         /**
  51          * Used to be GAID_FOR_UPDATE define. Used with getArticleID() and friends
  52          * to use the master DB
  53          */
  54         const GAID_FOR_UPDATE = 1;
  55
  56         /**
  57          * @name Private member variables
  58          * Please use the accessor functions instead.
  59          * @private
  60          */
  61         // @{
  62
  63         /** @var string Text form (spaces not underscores) of the main part */
  64         public $mTextform = '';
  65
  66         /** @var string URL-encoded form of the main part */
  67         public $mUrlform = '';
  68
  69         /** @var string Main part with underscores */
  70         public $mDbkeyform = '';
  71
  72         /** @var string Database key with the initial letter in the case specified by the user */
  73         protected $mUserCaseDBKey;
  74
  75         /** @var int Namespace index, i.e. one of the NS_xxxx constants */
  76         public $mNamespace = NS_MAIN;
  77
  78         /** @var string Interwiki prefix */
  79         public $mInterwiki = '';
  80
  81         /** @var bool Was this Title created from a string with a local interwiki prefix? */
  82         private $mLocalInterwiki = false;
  83
  84         /** @var string Title fragment (i.e. the bit after the #) */
  85         public $mFragment = '';
  86
  87         /** @var int Article ID, fetched from the link cache on demand */
  88         public $mArticleID = -1;
  89
  90         /** @var bool|int ID of most recent revision */
  91         protected $mLatestID = false;
  92
  93         /**
  94          * @var bool|string ID of the page's content model, i.e. one of the
  95          *   CONTENT_MODEL_XXX constants
  96          */
  97         private $mContentModel = false;
  98
  99         /**
 100          * @var bool If a content model was forced via setContentModel()
 101          *   this will be true to avoid having other code paths reset it
 102          */
 103         private $mForcedContentModel = false;
 104
 105         /** @var int Estimated number of revisions; null of not loaded */
 106         private $mEstimateRevisions;
 107
 108         /** @var array Array of groups allowed to edit this article */
 109         public $mRestrictions = [];
 110
 111         /** @var string|bool */
 112         protected $mOldRestrictions = false;
 113
 114         /** @var bool Cascade restrictions on this page to included templates and images? */
 115         public $mCascadeRestriction;
 116
 117         /** Caching the results of getCascadeProtectionSources */
 118         public $mCascadingRestrictions;
 119
 120         /** @var array When do the restrictions on this page expire? */
 121         protected $mRestrictionsExpiry = [];
 122
 123         /** @var bool Are cascading restrictions in effect on this page? */
 124         protected $mHasCascadingRestrictions;
 125
 126         /** @var array Where are the cascading restrictions coming from on this page? */
 127         public $mCascadeSources;
 128
 129         /** @var bool Boolean for initialisation on demand */
 130         public $mRestrictionsLoaded = false;
 131
 132         /** @var string Text form including namespace/interwiki, initialised on demand */
 133         protected $mPrefixedText = null;
 134
 135         /** @var mixed Cached value for getTitleProtection (create protection) */
 136         public $mTitleProtection;
 137
 138         /**
 139          * @var int Namespace index when there is no namespace. Don't change the
 140          *   following default, NS_MAIN is hardcoded in several places. See T2696.
 141          *   Zero except in {{transclusion}} tags.
 142          */
 143         public $mDefaultNamespace = NS_MAIN;
 144
 145         /** @var int The page length, 0 for special pages */
 146         protected $mLength = -1;
 147
 148         /** @var null Is the article at this title a redirect? */
 149         public $mRedirect = null;
 150
 151         /** @var array Associative array of user ID -> timestamp/false */
 152         private $mNotificationTimestamp = [];
 153
 154         /** @var bool Whether a page has any subpages */
 155         private $mHasSubpages;
 156
 157         /** @var bool The (string) language code of the page's language and content code. */
 158         private $mPageLanguage = false;
 159
 160         /** @var string|bool|null The page language code from the database, null if not saved in
 161          * the database or false if not loaded, yet. */
 162         private $mDbPageLanguage = false;
 163
 164         /** @var TitleValue A corresponding TitleValue object */
 165         private $mTitleValue = null;
 166
 167         /** @var bool Would deleting this page be a big deletion? */
 168         private $mIsBigDeletion = null;
 169         // @}
 170
 171         /**
 172          * B/C kludge: provide a TitleParser for use by Title.
 173          * Ideally, Title would have no methods that need this.
 174          * Avoid usage of this singleton by using TitleValue
 175          * and the associated services when possible.
 176          *
 177          * @return TitleFormatter
 178          */
 179         private static function getTitleFormatter() {
 180                 return MediaWikiServices::getInstance()->getTitleFormatter();
 181         }
 182
 183         /**
 184          * B/C kludge: provide an InterwikiLookup for use by Title.
 185          * Ideally, Title would have no methods that need this.
 186          * Avoid usage of this singleton by using TitleValue
 187          * and the associated services when possible.
 188          *
 189          * @return InterwikiLookup
 190          */
 191         private static function getInterwikiLookup() {
 192                 return MediaWikiServices::getInstance()->getInterwikiLookup();
 193         }
 194
 195         /**
 196          * @access protected
 197          */
 198         function __construct() {
 199         }
 200
 201         /**
 202          * Create a new Title from a prefixed DB key
 203          *
 204          * @param string $key The database key, which has underscores
 205          *      instead of spaces, possibly including namespace and
 206          *      interwiki prefixes
 207          * @return Title|null Title, or null on an error
 208          */
 209         public static function newFromDBkey( $key ) {
 210                 $t = new Title();
 211                 $t->mDbkeyform = $key;
 212
 213                 try {
 214                         $t->secureAndSplit();
 215                         return $t;
 216                 } catch ( MalformedTitleException $ex ) {
 217                         return null;
 218                 }
 219         }
 220
 221         /**
 222          * Create a new Title from a TitleValue
 223          *
 224          * @param TitleValue $titleValue Assumed to be safe.
 225          *
 226          * @return Title
 227          */
 228         public static function newFromTitleValue( TitleValue $titleValue ) {
 229                 return self::newFromLinkTarget( $titleValue );
 230         }
 231
 232         /**
 233          * Create a new Title from a LinkTarget
 234          *
 235          * @param LinkTarget $linkTarget Assumed to be safe.
 236          *
 237          * @return Title
 238          */
 239         public static function newFromLinkTarget( LinkTarget $linkTarget ) {
 240                 if ( $linkTarget instanceof Title ) {
 241                         // Special case if it's already a Title object
 242                         return $linkTarget;
 243                 }
 244                 return self::makeTitle(
 245                         $linkTarget->getNamespace(),
 246                         $linkTarget->getText(),
 247                         $linkTarget->getFragment(),
 248                         $linkTarget->getInterwiki()
 249                 );
 250         }
 251
 252         /**
 253          * Create a new Title from text, such as what one would find in a link. De-
 254          * codes any HTML entities in the text.
 255          *
 256          * Title objects returned by this method are guaranteed to be valid, and
 257          * thus return true from the isValid() method.
 258          *
 259          * @param string|int|null $text The link text; spaces, prefixes, and an
 260          *   initial ':' indicating the main namespace are accepted.
 261          * @param int $defaultNamespace The namespace to use if none is specified
 262          *   by a prefix.  If you want to force a specific namespace even if
 263          *   $text might begin with a namespace prefix, use makeTitle() or
 264          *   makeTitleSafe().
 265          * @throws InvalidArgumentException
 266          * @return Title|null Title or null on an error.
 267          */
 268         public static function newFromText( $text, $defaultNamespace = NS_MAIN ) {
 269                 // DWIM: Integers can be passed in here when page titles are used as array keys.
 270                 if ( $text !== null && !is_string( $text ) && !is_int( $text ) ) {
 271                         throw new InvalidArgumentException( '$text must be a string.' );
 272                 }
 273                 if ( $text === null ) {
 274                         return null;
 275                 }
 276
 277                 try {
 278                         return self::newFromTextThrow( strval( $text ), $defaultNamespace );
 279                 } catch ( MalformedTitleException $ex ) {
 280                         return null;
 281                 }
 282         }
 283
 284         /**
 285          * Like Title::newFromText(), but throws MalformedTitleException when the title is invalid,
 286          * rather than returning null.
 287          *
 288          * The exception subclasses encode detailed information about why the title is invalid.
 289          *
 290          * Title objects returned by this method are guaranteed to be valid, and
 291          * thus return true from the isValid() method.
 292          *
 293          * @see Title::newFromText
 294          *
 295          * @since 1.25
 296          * @param string $text Title text to check
 297          * @param int $defaultNamespace
 298          * @throws MalformedTitleException If the title is invalid
 299          * @return Title
 300          */
 301         public static function newFromTextThrow( $text, $defaultNamespace = NS_MAIN ) {
 302                 if ( is_object( $text ) ) {
 303                         throw new MWException( '$text must be a string, given an object' );
 304                 }
 305
 306                 $titleCache = self::getTitleCache();
 307
 308                 // Wiki pages often contain multiple links to the same page.
 309                 // Title normalization and parsing can become expensive on pages with many
 310                 // links, so we can save a little time by caching them.
 311                 // In theory these are value objects and won't get changed...
 312                 if ( $defaultNamespace == NS_MAIN ) {
 313                         $t = $titleCache->get( $text );
 314                         if ( $t ) {
 315                                 return $t;
 316                         }
 317                 }
 318
 319                 // Convert things like &eacute; &#257; or &#x3017; into normalized (T16952) text
 320                 $filteredText = Sanitizer::decodeCharReferencesAndNormalize( $text );
 321
 322                 $t = new Title();
 323                 $t->mDbkeyform = strtr( $filteredText, ' ', '_' );
 324                 $t->mDefaultNamespace = intval( $defaultNamespace );
 325
 326                 $t->secureAndSplit();
 327                 if ( $defaultNamespace == NS_MAIN ) {
 328                         $titleCache->set( $text, $t );
 329                 }
 330                 return $t;
 331         }
 332
 333         /**
 334          * THIS IS NOT THE FUNCTION YOU WANT. Use Title::newFromText().
 335          *
 336          * Example of wrong and broken code:
 337          * $title = Title::newFromURL( $wgRequest->getVal( 'title' ) );
 338          *
 339          * Example of right code:
 340          * $title = Title::newFromText( $wgRequest->getVal( 'title' ) );
 341          *
 342          * Create a new Title from URL-encoded text. Ensures that
 343          * the given title's length does not exceed the maximum.
 344          *
 345          * @param string $url The title, as might be taken from a URL
 346          * @return Title|null The new object, or null on an error
 347          */
 348         public static function newFromURL( $url ) {
 349                 $t = new Title();
 350
 351                 # For compatibility with old buggy URLs. "+" is usually not valid in titles,
 352                 # but some URLs used it as a space replacement and they still come
 353                 # from some external search tools.
 354                 if ( strpos( self::legalChars(), '+' ) === false ) {
 355                         $url = strtr( $url, '+', ' ' );
 356                 }
 357
 358                 $t->mDbkeyform = strtr( $url, ' ', '_' );
 359
 360                 try {
 361                         $t->secureAndSplit();
 362                         return $t;
 363                 } catch ( MalformedTitleException $ex ) {
 364                         return null;
 365                 }
 366         }
 367
 368         /**
 369          * @return HashBagOStuff
 370          */
 371         private static function getTitleCache() {
 372                 if ( self::$titleCache == null ) {
 373                         self::$titleCache = new HashBagOStuff( [ 'maxKeys' => self::CACHE_MAX ] );
 374                 }
 375                 return self::$titleCache;
 376         }
 377
 378         /**
 379          * Returns a list of fields that are to be selected for initializing Title
 380          * objects or LinkCache entries. Uses $wgContentHandlerUseDB to determine
 381          * whether to include page_content_model.
 382          *
 383          * @return array
 384          */
 385         protected static function getSelectFields() {
 386                 global $wgContentHandlerUseDB, $wgPageLanguageUseDB;
 387
 388                 $fields = [
 389                         'page_namespace', 'page_title', 'page_id',
 390                         'page_len', 'page_is_redirect', 'page_latest',
 391                 ];
 392
 393                 if ( $wgContentHandlerUseDB ) {
 394                         $fields[] = 'page_content_model';
 395                 }
 396
 397                 if ( $wgPageLanguageUseDB ) {
 398                         $fields[] = 'page_lang';
 399                 }
 400
 401                 return $fields;
 402         }
 403
 404         /**
 405          * Create a new Title from an article ID
 406          *
 407          * @param int $id The page_id corresponding to the Title to create
 408          * @param int $flags Use Title::GAID_FOR_UPDATE to use master
 409          * @return Title|null The new object, or null on an error
 410          */
 411         public static function newFromID( $id, $flags = 0 ) {
 412                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_REPLICA );
 413                 $row = $db->selectRow(
 414                         'page',
 415                         self::getSelectFields(),
 416                         [ 'page_id' => $id ],
 417                         __METHOD__
 418                 );
 419                 if ( $row !== false ) {
 420                         $title = self::newFromRow( $row );
 421                 } else {
 422                         $title = null;
 423                 }
 424                 return $title;
 425         }
 426
 427         /**
 428          * Make an array of titles from an array of IDs
 429          *
 430          * @param int[] $ids Array of IDs
 431          * @return Title[] Array of Titles
 432          */
 433         public static function newFromIDs( $ids ) {
 434                 if ( !count( $ids ) ) {
 435                         return [];
 436                 }
 437                 $dbr = wfGetDB( DB_REPLICA );
 438
 439                 $res = $dbr->select(
 440                         'page',
 441                         self::getSelectFields(),
 442                         [ 'page_id' => $ids ],
 443                         __METHOD__
 444                 );
 445
 446                 $titles = [];
 447                 foreach ( $res as $row ) {
 448                         $titles[] = self::newFromRow( $row );
 449                 }
 450                 return $titles;
 451         }
 452
 453         /**
 454          * Make a Title object from a DB row
 455          *
 456          * @param stdClass $row Object database row (needs at least page_title,page_namespace)
 457          * @return Title Corresponding Title
 458          */
 459         public static function newFromRow( $row ) {
 460                 $t = self::makeTitle( $row->page_namespace, $row->page_title );
 461                 $t->loadFromRow( $row );
 462                 return $t;
 463         }
 464
 465         /**
 466          * Load Title object fields from a DB row.
 467          * If false is given, the title will be treated as non-existing.
 468          *
 469          * @param stdClass|bool $row Database row
 470          */
 471         public function loadFromRow( $row ) {
 472                 if ( $row ) { // page found
 473                         if ( isset( $row->page_id ) ) {
 474                                 $this->mArticleID = (int)$row->page_id;
 475                         }
 476                         if ( isset( $row->page_len ) ) {
 477                                 $this->mLength = (int)$row->page_len;
 478                         }
 479                         if ( isset( $row->page_is_redirect ) ) {
 480                                 $this->mRedirect = (bool)$row->page_is_redirect;
 481                         }
 482                         if ( isset( $row->page_latest ) ) {
 483                                 $this->mLatestID = (int)$row->page_latest;
 484                         }
 485                         if ( !$this->mForcedContentModel && isset( $row->page_content_model ) ) {
 486                                 $this->mContentModel = strval( $row->page_content_model );
 487                         } elseif ( !$this->mForcedContentModel ) {
 488                                 $this->mContentModel = false; # initialized lazily in getContentModel()
 489                         }
 490                         if ( isset( $row->page_lang ) ) {
 491                                 $this->mDbPageLanguage = (string)$row->page_lang;
 492                         }
 493                         if ( isset( $row->page_restrictions ) ) {
 494                                 $this->mOldRestrictions = $row->page_restrictions;
 495                         }
 496                 } else { // page not found
 497                         $this->mArticleID = 0;
 498                         $this->mLength = 0;
 499                         $this->mRedirect = false;
 500                         $this->mLatestID = 0;
 501                         if ( !$this->mForcedContentModel ) {
 502                                 $this->mContentModel = false; # initialized lazily in getContentModel()
 503                         }
 504                 }
 505         }
 506
 507         /**
 508          * Create a new Title from a namespace index and a DB key.
 509          *
 510          * It's assumed that $ns and $title are safe, for instance when
 511          * they came directly from the database or a special page name,
 512          * not from user input.
 513          *
 514          * No validation is applied. For convenience, spaces are normalized
 515          * to underscores, so that e.g. user_text fields can be used directly.
 516          *
 517          * @note This method may return Title objects that are "invalid"
 518          * according to the isValid() method. This is usually caused by
 519          * configuration changes: e.g. a namespace that was once defined is
 520          * no longer configured, or a character that was once allowed in
 521          * titles is now forbidden.
 522          *
 523          * @param int $ns The namespace of the article
 524          * @param string $title The unprefixed database key form
 525          * @param string $fragment The link fragment (after the "#")
 526          * @param string $interwiki The interwiki prefix
 527          * @return Title The new object
 528          */
 529         public static function makeTitle( $ns, $title, $fragment = '', $interwiki = '' ) {
 530                 $t = new Title();
 531                 $t->mInterwiki = $interwiki;
 532                 $t->mFragment = $fragment;
 533                 $t->mNamespace = $ns = intval( $ns );
 534                 $t->mDbkeyform = strtr( $title, ' ', '_' );
 535                 $t->mArticleID = ( $ns >= 0 ) ? -1 : 0;
 536                 $t->mUrlform = wfUrlencode( $t->mDbkeyform );
 537                 $t->mTextform = strtr( $title, '_', ' ' );
 538                 $t->mContentModel = false; # initialized lazily in getContentModel()
 539                 return $t;
 540         }
 541
 542         /**
 543          * Create a new Title from a namespace index and a DB key.
 544          * The parameters will be checked for validity, which is a bit slower
 545          * than makeTitle() but safer for user-provided data.
 546          *
 547          * Title objects returned by makeTitleSafe() are guaranteed to be valid,
 548          * that is, they return true from the isValid() method. If no valid Title
 549          * can be constructed from the input, this method returns null.
 550          *
 551          * @param int $ns The namespace of the article
 552          * @param string $title Database key form
 553          * @param string $fragment The link fragment (after the "#")
 554          * @param string $interwiki Interwiki prefix
 555          * @return Title|null The new object, or null on an error
 556          */
 557         public static function makeTitleSafe( $ns, $title, $fragment = '', $interwiki = '' ) {
 558                 // NOTE: ideally, this would just call makeTitle() and then isValid(),
 559                 // but presently, that means more overhead on a potential performance hotspot.
 560
 561                 if ( !MWNamespace::exists( $ns ) ) {
 562                         return null;
 563                 }
 564
 565                 $t = new Title();
 566                 $t->mDbkeyform = self::makeName( $ns, $title, $fragment, $interwiki, true );
 567
 568                 try {
 569                         $t->secureAndSplit();
 570                         return $t;
 571                 } catch ( MalformedTitleException $ex ) {
 572                         return null;
 573                 }
 574         }
 575
 576         /**
 577          * Create a new Title for the Main Page
 578          *
 579          * @return Title The new object
 580          */
 581         public static function newMainPage() {
 582                 $title = self::newFromText( wfMessage( 'mainpage' )->inContentLanguage()->text() );
 583                 // Don't give fatal errors if the message is broken
 584                 if ( !$title ) {
 585                         $title = self::newFromText( 'Main Page' );
 586                 }
 587                 return $title;
 588         }
 589
 590         /**
 591          * Get the prefixed DB key associated with an ID
 592          *
 593          * @param int $id The page_id of the article
 594          * @return Title|null An object representing the article, or null if no such article was found
 595          */
 596         public static function nameOf( $id ) {
 597                 $dbr = wfGetDB( DB_REPLICA );
 598
 599                 $s = $dbr->selectRow(
 600                         'page',
 601                         [ 'page_namespace', 'page_title' ],
 602                         [ 'page_id' => $id ],
 603                         __METHOD__
 604                 );
 605                 if ( $s === false ) {
 606                         return null;
 607                 }
 608
 609                 $n = self::makeName( $s->page_namespace, $s->page_title );
 610                 return $n;
 611         }
 612
 613         /**
 614          * Get a regex character class describing the legal characters in a link
 615          *
 616          * @return string The list of characters, not delimited
 617          */
 618         public static function legalChars() {
 619                 global $wgLegalTitleChars;
 620                 return $wgLegalTitleChars;
 621         }
 622
 623         /**
 624          * Returns a simple regex that will match on characters and sequences invalid in titles.
 625          * Note that this doesn't pick up many things that could be wrong with titles, but that
 626          * replacing this regex with something valid will make many titles valid.
 627          *
 628          * @deprecated since 1.25, use MediaWikiTitleCodec::getTitleInvalidRegex() instead
 629          *
 630          * @return string Regex string
 631          */
 632         static function getTitleInvalidRegex() {
 633                 wfDeprecated( __METHOD__, '1.25' );
 634                 return MediaWikiTitleCodec::getTitleInvalidRegex();
 635         }
 636
 637         /**
 638          * Utility method for converting a character sequence from bytes to Unicode.
 639          *
 640          * Primary usecase being converting $wgLegalTitleChars to a sequence usable in
 641          * javascript, as PHP uses UTF-8 bytes where javascript uses Unicode code units.
 642          *
 643          * @param string $byteClass
 644          * @return string
 645          */
 646         public static function convertByteClassToUnicodeClass( $byteClass ) {
 647                 $length = strlen( $byteClass );
 648                 // Input token queue
 649                 $x0 = $x1 = $x2 = '';
 650                 // Decoded queue
 651                 $d0 = $d1 = $d2 = '';
 652                 // Decoded integer codepoints
 653                 $ord0 = $ord1 = $ord2 = 0;
 654                 // Re-encoded queue
 655                 $r0 = $r1 = $r2 = '';
 656                 // Output
 657                 $out = '';
 658                 // Flags
 659                 $allowUnicode = false;
 660                 for ( $pos = 0; $pos < $length; $pos++ ) {
 661                         // Shift the queues down
 662                         $x2 = $x1;
 663                         $x1 = $x0;
 664                         $d2 = $d1;
 665                         $d1 = $d0;
 666                         $ord2 = $ord1;
 667                         $ord1 = $ord0;
 668                         $r2 = $r1;
 669                         $r1 = $r0;
 670                         // Load the current input token and decoded values
 671                         $inChar = $byteClass[$pos];
 672                         if ( $inChar == '\\' ) {
 673                                 if ( preg_match( '/x([0-9a-fA-F]{2})/A', $byteClass, $m, 0, $pos + 1 ) ) {
 674                                         $x0 = $inChar . $m[0];
 675                                         $d0 = chr( hexdec( $m[1] ) );
 676                                         $pos += strlen( $m[0] );
 677                                 } elseif ( preg_match( '/[0-7]{3}/A', $byteClass, $m, 0, $pos + 1 ) ) {
 678                                         $x0 = $inChar . $m[0];
 679                                         $d0 = chr( octdec( $m[0] ) );
 680                                         $pos += strlen( $m[0] );
 681                                 } elseif ( $pos + 1 >= $length ) {
 682                                         $x0 = $d0 = '\\';
 683                                 } else {
 684                                         $d0 = $byteClass[$pos + 1];
 685                                         $x0 = $inChar . $d0;
 686                                         $pos += 1;
 687                                 }
 688                         } else {
 689                                 $x0 = $d0 = $inChar;
 690                         }
 691                         $ord0 = ord( $d0 );
 692                         // Load the current re-encoded value
 693                         if ( $ord0 < 32 || $ord0 == 0x7f ) {
 694                                 $r0 = sprintf( '\x%02x', $ord0 );
 695                         } elseif ( $ord0 >= 0x80 ) {
 696                                 // Allow unicode if a single high-bit character appears
 697                                 $r0 = sprintf( '\x%02x', $ord0 );
 698                                 $allowUnicode = true;
 699                         } elseif ( strpos( '-\\[]^', $d0 ) !== false ) {
 700                                 $r0 = '\\' . $d0;
 701                         } else {
 702                                 $r0 = $d0;
 703                         }
 704                         // Do the output
 705                         if ( $x0 !== '' && $x1 === '-' && $x2 !== '' ) {
 706                                 // Range
 707                                 if ( $ord2 > $ord0 ) {
 708                                         // Empty range
 709                                 } elseif ( $ord0 >= 0x80 ) {
 710                                         // Unicode range
 711                                         $allowUnicode = true;
 712                                         if ( $ord2 < 0x80 ) {
 713                                                 // Keep the non-unicode section of the range
 714                                                 $out .= "$r2-\\x7F";
 715                                         }
 716                                 } else {
 717                                         // Normal range
 718                                         $out .= "$r2-$r0";
 719                                 }
 720                                 // Reset state to the initial value
 721                                 $x0 = $x1 = $d0 = $d1 = $r0 = $r1 = '';
 722                         } elseif ( $ord2 < 0x80 ) {
 723                                 // ASCII character
 724                                 $out .= $r2;
 725                         }
 726                 }
 727                 if ( $ord1 < 0x80 ) {
 728                         $out .= $r1;
 729                 }
 730                 if ( $ord0 < 0x80 ) {
 731                         $out .= $r0;
 732                 }
 733                 if ( $allowUnicode ) {
 734                         $out .= '\u0080-\uFFFF';
 735                 }
 736                 return $out;
 737         }
 738
 739         /**
 740          * Make a prefixed DB key from a DB key and a namespace index
 741          *
 742          * @param int $ns Numerical representation of the namespace
 743          * @param string $title The DB key form the title
 744          * @param string $fragment The link fragment (after the "#")
 745          * @param string $interwiki The interwiki prefix
 746          * @param bool $canonicalNamespace If true, use the canonical name for
 747          *   $ns instead of the localized version.
 748          * @return string The prefixed form of the title
 749          */
 750         public static function makeName( $ns, $title, $fragment = '', $interwiki = '',
 751                 $canonicalNamespace = false
 752         ) {
 753                 global $wgContLang;
 754
 755                 if ( $canonicalNamespace ) {
 756                         $namespace = MWNamespace::getCanonicalName( $ns );
 757                 } else {
 758                         $namespace = $wgContLang->getNsText( $ns );
 759                 }
 760                 $name = $namespace == '' ? $title : "$namespace:$title";
 761                 if ( strval( $interwiki ) != '' ) {
 762                         $name = "$interwiki:$name";
 763                 }
 764                 if ( strval( $fragment ) != '' ) {
 765                         $name .= '#' . $fragment;
 766                 }
 767                 return $name;
 768         }
 769
 770         /**
 771          * Escape a text fragment, say from a link, for a URL
 772          *
 773          * @deprecated since 1.30, use Sanitizer::escapeIdForLink() or escapeIdForExternalInterwiki()
 774          *
 775          * @param string $fragment Containing a URL or link fragment (after the "#")
 776          * @return string Escaped string
 777          */
 778         static function escapeFragmentForURL( $fragment ) {
 779                 # Note that we don't urlencode the fragment.  urlencoded Unicode
 780                 # fragments appear not to work in IE (at least up to 7) or in at least
 781                 # one version of Opera 9.x.  The W3C validator, for one, doesn't seem
 782                 # to care if they aren't encoded.
 783                 return Sanitizer::escapeId( $fragment, 'noninitial' );
 784         }
 785
 786         /**
 787          * Callback for usort() to do title sorts by (namespace, title)
 788          *
 789          * @param LinkTarget $a
 790          * @param LinkTarget $b
 791          *
 792          * @return int Result of string comparison, or namespace comparison
 793          */
 794         public static function compare( LinkTarget $a, LinkTarget $b ) {
 795                 if ( $a->getNamespace() == $b->getNamespace() ) {
 796                         return strcmp( $a->getText(), $b->getText() );
 797                 } else {
 798                         return $a->getNamespace() - $b->getNamespace();
 799                 }
 800         }
 801
 802         /**
 803          * Returns true if the title is valid, false if it is invalid.
 804          *
 805          * Valid titles can be round-tripped via makeTitleSafe() and newFromText().
 806          * Invalid titles may get returned from makeTitle(), and it may be useful to
 807          * allow them to exist, e.g. in order to process log entries about pages in
 808          * namespaces that belong to extensions that are no longer installed.
 809          *
 810          * @note This method is relatively expensive. When constructing Title
 811          * objects that need to be valid, use an instantiator method that is guaranteed
 812          * to return valid titles, such as makeTitleSafe() or newFromText().
 813          *
 814          * @return bool
 815          */
 816         public function isValid() {
 817                 $ns = $this->getNamespace();
 818
 819                 if ( !MWNamespace::exists( $ns ) ) {
 820                         return false;
 821                 }
 822
 823                 try {
 824                         $parser = MediaWikiServices::getInstance()->getTitleParser();
 825                         $parser->parseTitle( $this->getDBkey(), $ns );
 826                         return true;
 827                 } catch ( MalformedTitleException $ex ) {
 828                         return false;
 829                 }
 830         }
 831
 832         /**
 833          * Determine whether the object refers to a page within
 834          * this project (either this wiki or a wiki with a local
 835          * interwiki, see https://www.mediawiki.org/wiki/Manual:Interwiki_table#iw_local )
 836          *
 837          * @return bool True if this is an in-project interwiki link or a wikilink, false otherwise
 838          */
 839         public function isLocal() {
 840                 if ( $this->isExternal() ) {
 841                         $iw = self::getInterwikiLookup()->fetch( $this->mInterwiki );
 842                         if ( $iw ) {
 843                                 return $iw->isLocal();
 844                         }
 845                 }
 846                 return true;
 847         }
 848
 849         /**
 850          * Is this Title interwiki?
 851          *
 852          * @return bool
 853          */
 854         public function isExternal() {
 855                 return $this->mInterwiki !== '';
 856         }
 857
 858         /**
 859          * Get the interwiki prefix
 860          *
 861          * Use Title::isExternal to check if a interwiki is set
 862          *
 863          * @return string Interwiki prefix
 864          */
 865         public function getInterwiki() {
 866                 return $this->mInterwiki;
 867         }
 868
 869         /**
 870          * Was this a local interwiki link?
 871          *
 872          * @return bool
 873          */
 874         public function wasLocalInterwiki() {
 875                 return $this->mLocalInterwiki;
 876         }
 877
 878         /**
 879          * Determine whether the object refers to a page within
 880          * this project and is transcludable.
 881          *
 882          * @return bool True if this is transcludable
 883          */
 884         public function isTrans() {
 885                 if ( !$this->isExternal() ) {
 886                         return false;
 887                 }
 888
 889                 return self::getInterwikiLookup()->fetch( $this->mInterwiki )->isTranscludable();
 890         }
 891
 892         /**
 893          * Returns the DB name of the distant wiki which owns the object.
 894          *
 895          * @return string|false The DB name
 896          */
 897         public function getTransWikiID() {
 898                 if ( !$this->isExternal() ) {
 899                         return false;
 900                 }
 901
 902                 return self::getInterwikiLookup()->fetch( $this->mInterwiki )->getWikiID();
 903         }
 904
 905         /**
 906          * Get a TitleValue object representing this Title.
 907          *
 908          * @note Not all valid Titles have a corresponding valid TitleValue
 909          * (e.g. TitleValues cannot represent page-local links that have a
 910          * fragment but no title text).
 911          *
 912          * @return TitleValue|null
 913          */
 914         public function getTitleValue() {
 915                 if ( $this->mTitleValue === null ) {
 916                         try {
 917                                 $this->mTitleValue = new TitleValue(
 918                                         $this->getNamespace(),
 919                                         $this->getDBkey(),
 920                                         $this->getFragment(),
 921                                         $this->getInterwiki()
 922                                 );
 923                         } catch ( InvalidArgumentException $ex ) {
 924                                 wfDebug( __METHOD__ . ': Can\'t create a TitleValue for [[' .
 925                                         $this->getPrefixedText() . ']]: ' . $ex->getMessage() . "\n" );
 926                         }
 927                 }
 928
 929                 return $this->mTitleValue;
 930         }
 931
 932         /**
 933          * Get the text form (spaces not underscores) of the main part
 934          *
 935          * @return string Main part of the title
 936          */
 937         public function getText() {
 938                 return $this->mTextform;
 939         }
 940
 941         /**
 942          * Get the URL-encoded form of the main part
 943          *
 944          * @return string Main part of the title, URL-encoded
 945          */
 946         public function getPartialURL() {
 947                 return $this->mUrlform;
 948         }
 949
 950         /**
 951          * Get the main part with underscores
 952          *
 953          * @return string Main part of the title, with underscores
 954          */
 955         public function getDBkey() {
 956                 return $this->mDbkeyform;
 957         }
 958
 959         /**
 960          * Get the DB key with the initial letter case as specified by the user
 961          *
 962          * @return string DB key
 963          */
 964         function getUserCaseDBKey() {
 965                 if ( !is_null( $this->mUserCaseDBKey ) ) {
 966                         return $this->mUserCaseDBKey;
 967                 } else {
 968                         // If created via makeTitle(), $this->mUserCaseDBKey is not set.
 969                         return $this->mDbkeyform;
 970                 }
 971         }
 972
 973         /**
 974          * Get the namespace index, i.e. one of the NS_xxxx constants.
 975          *
 976          * @return int Namespace index
 977          */
 978         public function getNamespace() {
 979                 return $this->mNamespace;
 980         }
 981
 982         /**
 983          * Get the page's content model id, see the CONTENT_MODEL_XXX constants.
 984          *
 985          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
 986          * @return string Content model id
 987          */
 988         public function getContentModel( $flags = 0 ) {
 989                 if ( !$this->mForcedContentModel
 990                         && ( !$this->mContentModel || $flags === self::GAID_FOR_UPDATE )
 991                         && $this->getArticleID( $flags )
 992                 ) {
 993                         $linkCache = LinkCache::singleton();
 994                         $linkCache->addLinkObj( $this ); # in case we already had an article ID
 995                         $this->mContentModel = $linkCache->getGoodLinkFieldObj( $this, 'model' );
 996                 }
 997
 998                 if ( !$this->mContentModel ) {
 999                         $this->mContentModel = ContentHandler::getDefaultModelFor( $this );
1000                 }
1001
1002                 return $this->mContentModel;
1003         }
1004
1005         /**
1006          * Convenience method for checking a title's content model name
1007          *
1008          * @param string $id The content model ID (use the CONTENT_MODEL_XXX constants).
1009          * @return bool True if $this->getContentModel() == $id
1010          */
1011         public function hasContentModel( $id ) {
1012                 return $this->getContentModel() == $id;
1013         }
1014
1015         /**
1016          * Set a proposed content model for the page for permissions
1017          * checking. This does not actually change the content model
1018          * of a title!
1019          *
1020          * Additionally, you should make sure you've checked
1021          * ContentHandler::canBeUsedOn() first.
1022          *
1023          * @since 1.28
1024          * @param string $model CONTENT_MODEL_XXX constant
1025          */
1026         public function setContentModel( $model ) {
1027                 $this->mContentModel = $model;
1028                 $this->mForcedContentModel = true;
1029         }
1030
1031         /**
1032          * Get the namespace text
1033          *
1034          * @return string|false Namespace text
1035          */
1036         public function getNsText() {
1037                 if ( $this->isExternal() ) {
1038                         // This probably shouldn't even happen,
1039                         // but for interwiki transclusion it sometimes does.
1040                         // Use the canonical namespaces if possible to try to
1041                         // resolve a foreign namespace.
1042                         if ( MWNamespace::exists( $this->mNamespace ) ) {
1043                                 return MWNamespace::getCanonicalName( $this->mNamespace );
1044                         }
1045                 }
1046
1047                 try {
1048                         $formatter = self::getTitleFormatter();
1049                         return $formatter->getNamespaceName( $this->mNamespace, $this->mDbkeyform );
1050                 } catch ( InvalidArgumentException $ex ) {
1051                         wfDebug( __METHOD__ . ': ' . $ex->getMessage() . "\n" );
1052                         return false;
1053                 }
1054         }
1055
1056         /**
1057          * Get the namespace text of the subject (rather than talk) page
1058          *
1059          * @return string Namespace text
1060          */
1061         public function getSubjectNsText() {
1062                 global $wgContLang;
1063                 return $wgContLang->getNsText( MWNamespace::getSubject( $this->mNamespace ) );
1064         }
1065
1066         /**
1067          * Get the namespace text of the talk page
1068          *
1069          * @return string Namespace text
1070          */
1071         public function getTalkNsText() {
1072                 global $wgContLang;
1073                 return $wgContLang->getNsText( MWNamespace::getTalk( $this->mNamespace ) );
1074         }
1075
1076         /**
1077          * Can this title have a corresponding talk page?
1078          *
1079          * @deprecated since 1.30, use canHaveTalkPage() instead.
1080          *
1081          * @return bool True if this title either is a talk page or can have a talk page associated.
1082          */
1083         public function canTalk() {
1084                 return $this->canHaveTalkPage();
1085         }
1086
1087         /**
1088          * Can this title have a corresponding talk page?
1089          *
1090          * @see MWNamespace::hasTalkNamespace
1091          * @since 1.30
1092          *
1093          * @return bool True if this title either is a talk page or can have a talk page associated.
1094          */
1095         public function canHaveTalkPage() {
1096                 return MWNamespace::hasTalkNamespace( $this->mNamespace );
1097         }
1098
1099         /**
1100          * Is this in a namespace that allows actual pages?
1101          *
1102          * @return bool
1103          */
1104         public function canExist() {
1105                 return $this->mNamespace >= NS_MAIN;
1106         }
1107
1108         /**
1109          * Can this title be added to a user's watchlist?
1110          *
1111          * @return bool
1112          */
1113         public function isWatchable() {
1114                 return !$this->isExternal() && MWNamespace::isWatchable( $this->getNamespace() );
1115         }
1116
1117         /**
1118          * Returns true if this is a special page.
1119          *
1120          * @return bool
1121          */
1122         public function isSpecialPage() {
1123                 return $this->getNamespace() == NS_SPECIAL;
1124         }
1125
1126         /**
1127          * Returns true if this title resolves to the named special page
1128          *
1129          * @param string $name The special page name
1130          * @return bool
1131          */
1132         public function isSpecial( $name ) {
1133                 if ( $this->isSpecialPage() ) {
1134                         list( $thisName, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $this->getDBkey() );
1135                         if ( $name == $thisName ) {
1136                                 return true;
1137                         }
1138                 }
1139                 return false;
1140         }
1141
1142         /**
1143          * If the Title refers to a special page alias which is not the local default, resolve
1144          * the alias, and localise the name as necessary.  Otherwise, return $this
1145          *
1146          * @return Title
1147          */
1148         public function fixSpecialName() {
1149                 if ( $this->isSpecialPage() ) {
1150                         list( $canonicalName, $par ) = SpecialPageFactory::resolveAlias( $this->mDbkeyform );
1151                         if ( $canonicalName ) {
1152                                 $localName = SpecialPageFactory::getLocalNameFor( $canonicalName, $par );
1153                                 if ( $localName != $this->mDbkeyform ) {
1154                                         return self::makeTitle( NS_SPECIAL, $localName );
1155                                 }
1156                         }
1157                 }
1158                 return $this;
1159         }
1160
1161         /**
1162          * Returns true if the title is inside the specified namespace.
1163          *
1164          * Please make use of this instead of comparing to getNamespace()
1165          * This function is much more resistant to changes we may make
1166          * to namespaces than code that makes direct comparisons.
1167          * @param int $ns The namespace
1168          * @return bool
1169          * @since 1.19
1170          */
1171         public function inNamespace( $ns ) {
1172                 return MWNamespace::equals( $this->getNamespace(), $ns );
1173         }
1174
1175         /**
1176          * Returns true if the title is inside one of the specified namespaces.
1177          *
1178          * @param int|int[] $namespaces,... The namespaces to check for
1179          * @return bool
1180          * @since 1.19
1181          */
1182         public function inNamespaces( /* ... */ ) {
1183                 $namespaces = func_get_args();
1184                 if ( count( $namespaces ) > 0 && is_array( $namespaces[0] ) ) {
1185                         $namespaces = $namespaces[0];
1186                 }
1187
1188                 foreach ( $namespaces as $ns ) {
1189                         if ( $this->inNamespace( $ns ) ) {
1190                                 return true;
1191                         }
1192                 }
1193
1194                 return false;
1195         }
1196
1197         /**
1198          * Returns true if the title has the same subject namespace as the
1199          * namespace specified.
1200          * For example this method will take NS_USER and return true if namespace
1201          * is either NS_USER or NS_USER_TALK since both of them have NS_USER
1202          * as their subject namespace.
1203          *
1204          * This is MUCH simpler than individually testing for equivalence
1205          * against both NS_USER and NS_USER_TALK, and is also forward compatible.
1206          * @since 1.19
1207          * @param int $ns
1208          * @return bool
1209          */
1210         public function hasSubjectNamespace( $ns ) {
1211                 return MWNamespace::subjectEquals( $this->getNamespace(), $ns );
1212         }
1213
1214         /**
1215          * Is this Title in a namespace which contains content?
1216          * In other words, is this a content page, for the purposes of calculating
1217          * statistics, etc?
1218          *
1219          * @return bool
1220          */
1221         public function isContentPage() {
1222                 return MWNamespace::isContent( $this->getNamespace() );
1223         }
1224
1225         /**
1226          * Would anybody with sufficient privileges be able to move this page?
1227          * Some pages just aren't movable.
1228          *
1229          * @return bool
1230          */
1231         public function isMovable() {
1232                 if ( !MWNamespace::isMovable( $this->getNamespace() ) || $this->isExternal() ) {
1233                         // Interwiki title or immovable namespace. Hooks don't get to override here
1234                         return false;
1235                 }
1236
1237                 $result = true;
1238                 Hooks::run( 'TitleIsMovable', [ $this, &$result ] );
1239                 return $result;
1240         }
1241
1242         /**
1243          * Is this the mainpage?
1244          * @note Title::newFromText seems to be sufficiently optimized by the title
1245          * cache that we don't need to over-optimize by doing direct comparisons and
1246          * accidentally creating new bugs where $title->equals( Title::newFromText() )
1247          * ends up reporting something differently than $title->isMainPage();
1248          *
1249          * @since 1.18
1250          * @return bool
1251          */
1252         public function isMainPage() {
1253                 return $this->equals( self::newMainPage() );
1254         }
1255
1256         /**
1257          * Is this a subpage?
1258          *
1259          * @return bool
1260          */
1261         public function isSubpage() {
1262                 return MWNamespace::hasSubpages( $this->mNamespace )
1263                         ? strpos( $this->getText(), '/' ) !== false
1264                         : false;
1265         }
1266
1267         /**
1268          * Is this a conversion table for the LanguageConverter?
1269          *
1270          * @return bool
1271          */
1272         public function isConversionTable() {
1273                 // @todo ConversionTable should become a separate content model.
1274
1275                 return $this->getNamespace() == NS_MEDIAWIKI &&
1276                         strpos( $this->getText(), 'Conversiontable/' ) === 0;
1277         }
1278
1279         /**
1280          * Does that page contain wikitext, or it is JS, CSS or whatever?
1281          *
1282          * @return bool
1283          */
1284         public function isWikitextPage() {
1285                 return $this->hasContentModel( CONTENT_MODEL_WIKITEXT );
1286         }
1287
1288         /**
1289          * Could this page contain custom CSS or JavaScript for the global UI.
1290          * This is generally true for pages in the MediaWiki namespace having CONTENT_MODEL_CSS
1291          * or CONTENT_MODEL_JAVASCRIPT.
1292          *
1293          * This method does *not* return true for per-user JS/CSS. Use isCssJsSubpage()
1294          * for that!
1295          *
1296          * Note that this method should not return true for pages that contain and
1297          * show "inactive" CSS or JS.
1298          *
1299          * @return bool
1300          * @todo FIXME: Rename to isSiteConfigPage() and remove deprecated hook
1301          */
1302         public function isCssOrJsPage() {
1303                 $isCssOrJsPage = NS_MEDIAWIKI == $this->mNamespace
1304                         && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1305                                 || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1306
1307                 return $isCssOrJsPage;
1308         }
1309
1310         /**
1311          * Is this a .css or .js subpage of a user page?
1312          * @return bool
1313          * @todo FIXME: Rename to isUserConfigPage()
1314          */
1315         public function isCssJsSubpage() {
1316                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1317                                 && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1318                                         || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) ) );
1319         }
1320
1321         /**
1322          * Trim down a .css or .js subpage title to get the corresponding skin name
1323          *
1324          * @return string Containing skin name from .css or .js subpage title
1325          */
1326         public function getSkinFromCssJsSubpage() {
1327                 $subpage = explode( '/', $this->mTextform );
1328                 $subpage = $subpage[count( $subpage ) - 1];
1329                 $lastdot = strrpos( $subpage, '.' );
1330                 if ( $lastdot === false ) {
1331                         return $subpage; # Never happens: only called for names ending in '.css' or '.js'
1332                 }
1333                 return substr( $subpage, 0, $lastdot );
1334         }
1335
1336         /**
1337          * Is this a .css subpage of a user page?
1338          *
1339          * @return bool
1340          */
1341         public function isCssSubpage() {
1342                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1343                         && $this->hasContentModel( CONTENT_MODEL_CSS ) );
1344         }
1345
1346         /**
1347          * Is this a .js subpage of a user page?
1348          *
1349          * @return bool
1350          */
1351         public function isJsSubpage() {
1352                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1353                         && $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1354         }
1355
1356         /**
1357          * Is this a talk page of some sort?
1358          *
1359          * @return bool
1360          */
1361         public function isTalkPage() {
1362                 return MWNamespace::isTalk( $this->getNamespace() );
1363         }
1364
1365         /**
1366          * Get a Title object associated with the talk page of this article
1367          *
1368          * @return Title The object for the talk page
1369          */
1370         public function getTalkPage() {
1371                 return self::makeTitle( MWNamespace::getTalk( $this->getNamespace() ), $this->getDBkey() );
1372         }
1373
1374         /**
1375          * Get a Title object associated with the talk page of this article,
1376          * if such a talk page can exist.
1377          *
1378          * @since 1.30
1379          *
1380          * @return Title|null The object for the talk page,
1381          *         or null if no associated talk page can exist, according to canHaveTalkPage().
1382          */
1383         public function getTalkPageIfDefined() {
1384                 if ( !$this->canHaveTalkPage() ) {
1385                         return null;
1386                 }
1387
1388                 return $this->getTalkPage();
1389         }
1390
1391         /**
1392          * Get a title object associated with the subject page of this
1393          * talk page
1394          *
1395          * @return Title The object for the subject page
1396          */
1397         public function getSubjectPage() {
1398                 // Is this the same title?
1399                 $subjectNS = MWNamespace::getSubject( $this->getNamespace() );
1400                 if ( $this->getNamespace() == $subjectNS ) {
1401                         return $this;
1402                 }
1403                 return self::makeTitle( $subjectNS, $this->getDBkey() );
1404         }
1405
1406         /**
1407          * Get the other title for this page, if this is a subject page
1408          * get the talk page, if it is a subject page get the talk page
1409          *
1410          * @since 1.25
1411          * @throws MWException If the page doesn't have an other page
1412          * @return Title
1413          */
1414         public function getOtherPage() {
1415                 if ( $this->isSpecialPage() ) {
1416                         throw new MWException( 'Special pages cannot have other pages' );
1417                 }
1418                 if ( $this->isTalkPage() ) {
1419                         return $this->getSubjectPage();
1420                 } else {
1421                         if ( !$this->canHaveTalkPage() ) {
1422                                 throw new MWException( "{$this->getPrefixedText()} does not have an other page" );
1423                         }
1424                         return $this->getTalkPage();
1425                 }
1426         }
1427
1428         /**
1429          * Get the default namespace index, for when there is no namespace
1430          *
1431          * @return int Default namespace index
1432          */
1433         public function getDefaultNamespace() {
1434                 return $this->mDefaultNamespace;
1435         }
1436
1437         /**
1438          * Get the Title fragment (i.e.\ the bit after the #) in text form
1439          *
1440          * Use Title::hasFragment to check for a fragment
1441          *
1442          * @return string Title fragment
1443          */
1444         public function getFragment() {
1445                 return $this->mFragment;
1446         }
1447
1448         /**
1449          * Check if a Title fragment is set
1450          *
1451          * @return bool
1452          * @since 1.23
1453          */
1454         public function hasFragment() {
1455                 return $this->mFragment !== '';
1456         }
1457
1458         /**
1459          * Get the fragment in URL form, including the "#" character if there is one
1460          *
1461          * @return string Fragment in URL form
1462          */
1463         public function getFragmentForURL() {
1464                 if ( !$this->hasFragment() ) {
1465                         return '';
1466                 } elseif ( $this->isExternal() && !$this->getTransWikiID() ) {
1467                         return '#' . Sanitizer::escapeIdForExternalInterwiki( $this->getFragment() );
1468                 }
1469                 return '#' . Sanitizer::escapeIdForLink( $this->getFragment() );
1470         }
1471
1472         /**
1473          * Set the fragment for this title. Removes the first character from the
1474          * specified fragment before setting, so it assumes you're passing it with
1475          * an initial "#".
1476          *
1477          * Deprecated for public use, use Title::makeTitle() with fragment parameter,
1478          * or Title::createFragmentTarget().
1479          * Still in active use privately.
1480          *
1481          * @private
1482          * @param string $fragment Text
1483          */
1484         public function setFragment( $fragment ) {
1485                 $this->mFragment = strtr( substr( $fragment, 1 ), '_', ' ' );
1486         }
1487
1488         /**
1489          * Creates a new Title for a different fragment of the same page.
1490          *
1491          * @since 1.27
1492          * @param string $fragment
1493          * @return Title
1494          */
1495         public function createFragmentTarget( $fragment ) {
1496                 return self::makeTitle(
1497                         $this->getNamespace(),
1498                         $this->getText(),
1499                         $fragment,
1500                         $this->getInterwiki()
1501                 );
1502         }
1503
1504         /**
1505          * Prefix some arbitrary text with the namespace or interwiki prefix
1506          * of this object
1507          *
1508          * @param string $name The text
1509          * @return string The prefixed text
1510          */
1511         private function prefix( $name ) {
1512                 global $wgContLang;
1513
1514                 $p = '';
1515                 if ( $this->isExternal() ) {
1516                         $p = $this->mInterwiki . ':';
1517                 }
1518
1519                 if ( 0 != $this->mNamespace ) {
1520                         $nsText = $this->getNsText();
1521
1522                         if ( $nsText === false ) {
1523                                 // See T165149. Awkward, but better than erroneously linking to the main namespace.
1524                                 $nsText = $wgContLang->getNsText( NS_SPECIAL ) . ":Badtitle/NS{$this->mNamespace}";
1525                         }
1526
1527                         $p .= $nsText . ':';
1528                 }
1529                 return $p . $name;
1530         }
1531
1532         /**
1533          * Get the prefixed database key form
1534          *
1535          * @return string The prefixed title, with underscores and
1536          *  any interwiki and namespace prefixes
1537          */
1538         public function getPrefixedDBkey() {
1539                 $s = $this->prefix( $this->mDbkeyform );
1540                 $s = strtr( $s, ' ', '_' );
1541                 return $s;
1542         }
1543
1544         /**
1545          * Get the prefixed title with spaces.
1546          * This is the form usually used for display
1547          *
1548          * @return string The prefixed title, with spaces
1549          */
1550         public function getPrefixedText() {
1551                 if ( $this->mPrefixedText === null ) {
1552                         $s = $this->prefix( $this->mTextform );
1553                         $s = strtr( $s, '_', ' ' );
1554                         $this->mPrefixedText = $s;
1555                 }
1556                 return $this->mPrefixedText;
1557         }
1558
1559         /**
1560          * Return a string representation of this title
1561          *
1562          * @return string Representation of this title
1563          */
1564         public function __toString() {
1565                 return $this->getPrefixedText();
1566         }
1567
1568         /**
1569          * Get the prefixed title with spaces, plus any fragment
1570          * (part beginning with '#')
1571          *
1572          * @return string The prefixed title, with spaces and the fragment, including '#'
1573          */
1574         public function getFullText() {
1575                 $text = $this->getPrefixedText();
1576                 if ( $this->hasFragment() ) {
1577                         $text .= '#' . $this->getFragment();
1578                 }
1579                 return $text;
1580         }
1581
1582         /**
1583          * Get the root page name text without a namespace, i.e. the leftmost part before any slashes
1584          *
1585          * @par Example:
1586          * @code
1587          * Title::newFromText('User:Foo/Bar/Baz')->getRootText();
1588          * # returns: 'Foo'
1589          * @endcode
1590          *
1591          * @return string Root name
1592          * @since 1.20
1593          */
1594         public function getRootText() {
1595                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1596                         return $this->getText();
1597                 }
1598
1599                 return strtok( $this->getText(), '/' );
1600         }
1601
1602         /**
1603          * Get the root page name title, i.e. the leftmost part before any slashes
1604          *
1605          * @par Example:
1606          * @code
1607          * Title::newFromText('User:Foo/Bar/Baz')->getRootTitle();
1608          * # returns: Title{User:Foo}
1609          * @endcode
1610          *
1611          * @return Title Root title
1612          * @since 1.20
1613          */
1614         public function getRootTitle() {
1615                 return self::makeTitle( $this->getNamespace(), $this->getRootText() );
1616         }
1617
1618         /**
1619          * Get the base page name without a namespace, i.e. the part before the subpage name
1620          *
1621          * @par Example:
1622          * @code
1623          * Title::newFromText('User:Foo/Bar/Baz')->getBaseText();
1624          * # returns: 'Foo/Bar'
1625          * @endcode
1626          *
1627          * @return string Base name
1628          */
1629         public function getBaseText() {
1630                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1631                         return $this->getText();
1632                 }
1633
1634                 $parts = explode( '/', $this->getText() );
1635                 # Don't discard the real title if there's no subpage involved
1636                 if ( count( $parts ) > 1 ) {
1637                         unset( $parts[count( $parts ) - 1] );
1638                 }
1639                 return implode( '/', $parts );
1640         }
1641
1642         /**
1643          * Get the base page name title, i.e. the part before the subpage name
1644          *
1645          * @par Example:
1646          * @code
1647          * Title::newFromText('User:Foo/Bar/Baz')->getBaseTitle();
1648          * # returns: Title{User:Foo/Bar}
1649          * @endcode
1650          *
1651          * @return Title Base title
1652          * @since 1.20
1653          */
1654         public function getBaseTitle() {
1655                 return self::makeTitle( $this->getNamespace(), $this->getBaseText() );
1656         }
1657
1658         /**
1659          * Get the lowest-level subpage name, i.e. the rightmost part after any slashes
1660          *
1661          * @par Example:
1662          * @code
1663          * Title::newFromText('User:Foo/Bar/Baz')->getSubpageText();
1664          * # returns: "Baz"
1665          * @endcode
1666          *
1667          * @return string Subpage name
1668          */
1669         public function getSubpageText() {
1670                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1671                         return $this->mTextform;
1672                 }
1673                 $parts = explode( '/', $this->mTextform );
1674                 return $parts[count( $parts ) - 1];
1675         }
1676
1677         /**
1678          * Get the title for a subpage of the current page
1679          *
1680          * @par Example:
1681          * @code
1682          * Title::newFromText('User:Foo/Bar/Baz')->getSubpage("Asdf");
1683          * # returns: Title{User:Foo/Bar/Baz/Asdf}
1684          * @endcode
1685          *
1686          * @param string $text The subpage name to add to the title
1687          * @return Title Subpage title
1688          * @since 1.20
1689          */
1690         public function getSubpage( $text ) {
1691                 return self::makeTitleSafe( $this->getNamespace(), $this->getText() . '/' . $text );
1692         }
1693
1694         /**
1695          * Get a URL-encoded form of the subpage text
1696          *
1697          * @return string URL-encoded subpage name
1698          */
1699         public function getSubpageUrlForm() {
1700                 $text = $this->getSubpageText();
1701                 $text = wfUrlencode( strtr( $text, ' ', '_' ) );
1702                 return $text;
1703         }
1704
1705         /**
1706          * Get a URL-encoded title (not an actual URL) including interwiki
1707          *
1708          * @return string The URL-encoded form
1709          */
1710         public function getPrefixedURL() {
1711                 $s = $this->prefix( $this->mDbkeyform );
1712                 $s = wfUrlencode( strtr( $s, ' ', '_' ) );
1713                 return $s;
1714         }
1715
1716         /**
1717          * Helper to fix up the get{Canonical,Full,Link,Local,Internal}URL args
1718          * get{Canonical,Full,Link,Local,Internal}URL methods accepted an optional
1719          * second argument named variant. This was deprecated in favor
1720          * of passing an array of option with a "variant" key
1721          * Once $query2 is removed for good, this helper can be dropped
1722          * and the wfArrayToCgi moved to getLocalURL();
1723          *
1724          * @since 1.19 (r105919)
1725          * @param array|string $query
1726          * @param string|string[]|bool $query2
1727          * @return string
1728          */
1729         private static function fixUrlQueryArgs( $query, $query2 = false ) {
1730                 if ( $query2 !== false ) {
1731                         wfDeprecated( "Title::get{Canonical,Full,Link,Local,Internal}URL " .
1732                                 "method called with a second parameter is deprecated. Add your " .
1733                                 "parameter to an array passed as the first parameter.", "1.19" );
1734                 }
1735                 if ( is_array( $query ) ) {
1736                         $query = wfArrayToCgi( $query );
1737                 }
1738                 if ( $query2 ) {
1739                         if ( is_string( $query2 ) ) {
1740                                 // $query2 is a string, we will consider this to be
1741                                 // a deprecated $variant argument and add it to the query
1742                                 $query2 = wfArrayToCgi( [ 'variant' => $query2 ] );
1743                         } else {
1744                                 $query2 = wfArrayToCgi( $query2 );
1745                         }
1746                         // If we have $query content add a & to it first
1747                         if ( $query ) {
1748                                 $query .= '&';
1749                         }
1750                         // Now append the queries together
1751                         $query .= $query2;
1752                 }
1753                 return $query;
1754         }
1755
1756         /**
1757          * Get a real URL referring to this title, with interwiki link and
1758          * fragment
1759          *
1760          * @see self::getLocalURL for the arguments.
1761          * @see wfExpandUrl
1762          * @param string|string[] $query
1763          * @param string|string[]|bool $query2
1764          * @param string $proto Protocol type to use in URL
1765          * @return string The URL
1766          */
1767         public function getFullURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1768                 $query = self::fixUrlQueryArgs( $query, $query2 );
1769
1770                 # Hand off all the decisions on urls to getLocalURL
1771                 $url = $this->getLocalURL( $query );
1772
1773                 # Expand the url to make it a full url. Note that getLocalURL has the
1774                 # potential to output full urls for a variety of reasons, so we use
1775                 # wfExpandUrl instead of simply prepending $wgServer
1776                 $url = wfExpandUrl( $url, $proto );
1777
1778                 # Finally, add the fragment.
1779                 $url .= $this->getFragmentForURL();
1780                 // Avoid PHP 7.1 warning from passing $this by reference
1781                 $titleRef = $this;
1782                 Hooks::run( 'GetFullURL', [ &$titleRef, &$url, $query ] );
1783                 return $url;
1784         }
1785
1786         /**
1787          * Get a url appropriate for making redirects based on an untrusted url arg
1788          *
1789          * This is basically the same as getFullUrl(), but in the case of external
1790          * interwikis, we send the user to a landing page, to prevent possible
1791          * phishing attacks and the like.
1792          *
1793          * @note Uses current protocol by default, since technically relative urls
1794          *   aren't allowed in redirects per HTTP spec, so this is not suitable for
1795          *   places where the url gets cached, as might pollute between
1796          *   https and non-https users.
1797          * @see self::getLocalURL for the arguments.
1798          * @param array|string $query
1799          * @param string $proto Protocol type to use in URL
1800          * @return string A url suitable to use in an HTTP location header.
1801          */
1802         public function getFullUrlForRedirect( $query = '', $proto = PROTO_CURRENT ) {
1803                 $target = $this;
1804                 if ( $this->isExternal() ) {
1805                         $target = SpecialPage::getTitleFor(
1806                                 'GoToInterwiki',
1807                                 $this->getPrefixedDBKey()
1808                         );
1809                 }
1810                 return $target->getFullUrl( $query, false, $proto );
1811         }
1812
1813         /**
1814          * Get a URL with no fragment or server name (relative URL) from a Title object.
1815          * If this page is generated with action=render, however,
1816          * $wgServer is prepended to make an absolute URL.
1817          *
1818          * @see self::getFullURL to always get an absolute URL.
1819          * @see self::getLinkURL to always get a URL that's the simplest URL that will be
1820          *  valid to link, locally, to the current Title.
1821          * @see self::newFromText to produce a Title object.
1822          *
1823          * @param string|string[] $query An optional query string,
1824          *   not used for interwiki links. Can be specified as an associative array as well,
1825          *   e.g., array( 'action' => 'edit' ) (keys and values will be URL-escaped).
1826          *   Some query patterns will trigger various shorturl path replacements.
1827          * @param string|string[]|bool $query2 An optional secondary query array. This one MUST
1828          *   be an array. If a string is passed it will be interpreted as a deprecated
1829          *   variant argument and urlencoded into a variant= argument.
1830          *   This second query argument will be added to the $query
1831          *   The second parameter is deprecated since 1.19. Pass it as a key,value
1832          *   pair in the first parameter array instead.
1833          *
1834          * @return string String of the URL.
1835          */
1836         public function getLocalURL( $query = '', $query2 = false ) {
1837                 global $wgArticlePath, $wgScript, $wgServer, $wgRequest;
1838
1839                 $query = self::fixUrlQueryArgs( $query, $query2 );
1840
1841                 $interwiki = self::getInterwikiLookup()->fetch( $this->mInterwiki );
1842                 if ( $interwiki ) {
1843                         $namespace = $this->getNsText();
1844                         if ( $namespace != '' ) {
1845                                 # Can this actually happen? Interwikis shouldn't be parsed.
1846                                 # Yes! It can in interwiki transclusion. But... it probably shouldn't.
1847                                 $namespace .= ':';
1848                         }
1849                         $url = $interwiki->getURL( $namespace . $this->getDBkey() );
1850                         $url = wfAppendQuery( $url, $query );
1851                 } else {
1852                         $dbkey = wfUrlencode( $this->getPrefixedDBkey() );
1853                         if ( $query == '' ) {
1854                                 $url = str_replace( '$1', $dbkey, $wgArticlePath );
1855                                 // Avoid PHP 7.1 warning from passing $this by reference
1856                                 $titleRef = $this;
1857                                 Hooks::run( 'GetLocalURL::Article', [ &$titleRef, &$url ] );
1858                         } else {
1859                                 global $wgVariantArticlePath, $wgActionPaths, $wgContLang;
1860                                 $url = false;
1861                                 $matches = [];
1862
1863                                 if ( !empty( $wgActionPaths )
1864                                         && preg_match( '/^(.*&|)action=([^&]*)(&(.*)|)$/', $query, $matches )
1865                                 ) {
1866                                         $action = urldecode( $matches[2] );
1867                                         if ( isset( $wgActionPaths[$action] ) ) {
1868                                                 $query = $matches[1];
1869                                                 if ( isset( $matches[4] ) ) {
1870                                                         $query .= $matches[4];
1871                                                 }
1872                                                 $url = str_replace( '$1', $dbkey, $wgActionPaths[$action] );
1873                                                 if ( $query != '' ) {
1874                                                         $url = wfAppendQuery( $url, $query );
1875                                                 }
1876                                         }
1877                                 }
1878
1879                                 if ( $url === false
1880                                         && $wgVariantArticlePath
1881                                         && preg_match( '/^variant=([^&]*)$/', $query, $matches )
1882                                         && $this->getPageLanguage()->equals( $wgContLang )
1883                                         && $this->getPageLanguage()->hasVariants()
1884                                 ) {
1885                                         $variant = urldecode( $matches[1] );
1886                                         if ( $this->getPageLanguage()->hasVariant( $variant ) ) {
1887                                                 // Only do the variant replacement if the given variant is a valid
1888                                                 // variant for the page's language.
1889                                                 $url = str_replace( '$2', urlencode( $variant ), $wgVariantArticlePath );
1890                                                 $url = str_replace( '$1', $dbkey, $url );
1891                                         }
1892                                 }
1893
1894                                 if ( $url === false ) {
1895                                         if ( $query == '-' ) {
1896                                                 $query = '';
1897                                         }
1898                                         $url = "{$wgScript}?title={$dbkey}&{$query}";
1899                                 }
1900                         }
1901                         // Avoid PHP 7.1 warning from passing $this by reference
1902                         $titleRef = $this;
1903                         Hooks::run( 'GetLocalURL::Internal', [ &$titleRef, &$url, $query ] );
1904
1905                         // @todo FIXME: This causes breakage in various places when we
1906                         // actually expected a local URL and end up with dupe prefixes.
1907                         if ( $wgRequest->getVal( 'action' ) == 'render' ) {
1908                                 $url = $wgServer . $url;
1909                         }
1910                 }
1911                 // Avoid PHP 7.1 warning from passing $this by reference
1912                 $titleRef = $this;
1913                 Hooks::run( 'GetLocalURL', [ &$titleRef, &$url, $query ] );
1914                 return $url;
1915         }
1916
1917         /**
1918          * Get a URL that's the simplest URL that will be valid to link, locally,
1919          * to the current Title.  It includes the fragment, but does not include
1920          * the server unless action=render is used (or the link is external).  If
1921          * there's a fragment but the prefixed text is empty, we just return a link
1922          * to the fragment.
1923          *
1924          * The result obviously should not be URL-escaped, but does need to be
1925          * HTML-escaped if it's being output in HTML.
1926          *
1927          * @param string|string[] $query
1928          * @param bool $query2
1929          * @param string|int|bool $proto A PROTO_* constant on how the URL should be expanded,
1930          *                               or false (default) for no expansion
1931          * @see self::getLocalURL for the arguments.
1932          * @return string The URL
1933          */
1934         public function getLinkURL( $query = '', $query2 = false, $proto = false ) {
1935                 if ( $this->isExternal() || $proto !== false ) {
1936                         $ret = $this->getFullURL( $query, $query2, $proto );
1937                 } elseif ( $this->getPrefixedText() === '' && $this->hasFragment() ) {
1938                         $ret = $this->getFragmentForURL();
1939                 } else {
1940                         $ret = $this->getLocalURL( $query, $query2 ) . $this->getFragmentForURL();
1941                 }
1942                 return $ret;
1943         }
1944
1945         /**
1946          * Get the URL form for an internal link.
1947          * - Used in various CDN-related code, in case we have a different
1948          * internal hostname for the server from the exposed one.
1949          *
1950          * This uses $wgInternalServer to qualify the path, or $wgServer
1951          * if $wgInternalServer is not set. If the server variable used is
1952          * protocol-relative, the URL will be expanded to http://
1953          *
1954          * @see self::getLocalURL for the arguments.
1955          * @param string $query
1956          * @param string|bool $query2
1957          * @return string The URL
1958          */
1959         public function getInternalURL( $query = '', $query2 = false ) {
1960                 global $wgInternalServer, $wgServer;
1961                 $query = self::fixUrlQueryArgs( $query, $query2 );
1962                 $server = $wgInternalServer !== false ? $wgInternalServer : $wgServer;
1963                 $url = wfExpandUrl( $server . $this->getLocalURL( $query ), PROTO_HTTP );
1964                 // Avoid PHP 7.1 warning from passing $this by reference
1965                 $titleRef = $this;
1966                 Hooks::run( 'GetInternalURL', [ &$titleRef, &$url, $query ] );
1967                 return $url;
1968         }
1969
1970         /**
1971          * Get the URL for a canonical link, for use in things like IRC and
1972          * e-mail notifications. Uses $wgCanonicalServer and the
1973          * GetCanonicalURL hook.
1974          *
1975          * NOTE: Unlike getInternalURL(), the canonical URL includes the fragment
1976          *
1977          * @see self::getLocalURL for the arguments.
1978          * @param string $query
1979          * @param string|bool $query2
1980          * @return string The URL
1981          * @since 1.18
1982          */
1983         public function getCanonicalURL( $query = '', $query2 = false ) {
1984                 $query = self::fixUrlQueryArgs( $query, $query2 );
1985                 $url = wfExpandUrl( $this->getLocalURL( $query ) . $this->getFragmentForURL(), PROTO_CANONICAL );
1986                 // Avoid PHP 7.1 warning from passing $this by reference
1987                 $titleRef = $this;
1988                 Hooks::run( 'GetCanonicalURL', [ &$titleRef, &$url, $query ] );
1989                 return $url;
1990         }
1991
1992         /**
1993          * Get the edit URL for this Title
1994          *
1995          * @return string The URL, or a null string if this is an interwiki link
1996          */
1997         public function getEditURL() {
1998                 if ( $this->isExternal() ) {
1999                         return '';
2000                 }
2001                 $s = $this->getLocalURL( 'action=edit' );
2002
2003                 return $s;
2004         }
2005
2006         /**
2007          * Can $user perform $action on this page?
2008          * This skips potentially expensive cascading permission checks
2009          * as well as avoids expensive error formatting
2010          *
2011          * Suitable for use for nonessential UI controls in common cases, but
2012          * _not_ for functional access control.
2013          *
2014          * May provide false positives, but should never provide a false negative.
2015          *
2016          * @param string $action Action that permission needs to be checked for
2017          * @param User $user User to check (since 1.19); $wgUser will be used if not provided.
2018          * @return bool
2019          */
2020         public function quickUserCan( $action, $user = null ) {
2021                 return $this->userCan( $action, $user, false );
2022         }
2023
2024         /**
2025          * Can $user perform $action on this page?
2026          *
2027          * @param string $action Action that permission needs to be checked for
2028          * @param User $user User to check (since 1.19); $wgUser will be used if not
2029          *   provided.
2030          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2031          * @return bool
2032          */
2033         public function userCan( $action, $user = null, $rigor = 'secure' ) {
2034                 if ( !$user instanceof User ) {
2035                         global $wgUser;
2036                         $user = $wgUser;
2037                 }
2038
2039                 return !count( $this->getUserPermissionsErrorsInternal( $action, $user, $rigor, true ) );
2040         }
2041
2042         /**
2043          * Can $user perform $action on this page?
2044          *
2045          * @todo FIXME: This *does not* check throttles (User::pingLimiter()).
2046          *
2047          * @param string $action Action that permission needs to be checked for
2048          * @param User $user User to check
2049          * @param string $rigor One of (quick,full,secure)
2050          *   - quick  : does cheap permission checks from replica DBs (usable for GUI creation)
2051          *   - full   : does cheap and expensive checks possibly from a replica DB
2052          *   - secure : does cheap and expensive checks, using the master as needed
2053          * @param array $ignoreErrors Array of Strings Set this to a list of message keys
2054          *   whose corresponding errors may be ignored.
2055          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
2056          */
2057         public function getUserPermissionsErrors(
2058                 $action, $user, $rigor = 'secure', $ignoreErrors = []
2059         ) {
2060                 $errors = $this->getUserPermissionsErrorsInternal( $action, $user, $rigor );
2061
2062                 // Remove the errors being ignored.
2063                 foreach ( $errors as $index => $error ) {
2064                         $errKey = is_array( $error ) ? $error[0] : $error;
2065
2066                         if ( in_array( $errKey, $ignoreErrors ) ) {
2067                                 unset( $errors[$index] );
2068                         }
2069                         if ( $errKey instanceof MessageSpecifier && in_array( $errKey->getKey(), $ignoreErrors ) ) {
2070                                 unset( $errors[$index] );
2071                         }
2072                 }
2073
2074                 return $errors;
2075         }
2076
2077         /**
2078          * Permissions checks that fail most often, and which are easiest to test.
2079          *
2080          * @param string $action The action to check
2081          * @param User $user User to check
2082          * @param array $errors List of current errors
2083          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2084          * @param bool $short Short circuit on first error
2085          *
2086          * @return array List of errors
2087          */
2088         private function checkQuickPermissions( $action, $user, $errors, $rigor, $short ) {
2089                 if ( !Hooks::run( 'TitleQuickPermissions',
2090                         [ $this, $user, $action, &$errors, ( $rigor !== 'quick' ), $short ] )
2091                 ) {
2092                         return $errors;
2093                 }
2094
2095                 if ( $action == 'create' ) {
2096                         if (
2097                                 ( $this->isTalkPage() && !$user->isAllowed( 'createtalk' ) ) ||
2098                                 ( !$this->isTalkPage() && !$user->isAllowed( 'createpage' ) )
2099                         ) {
2100                                 $errors[] = $user->isAnon() ? [ 'nocreatetext' ] : [ 'nocreate-loggedin' ];
2101                         }
2102                 } elseif ( $action == 'move' ) {
2103                         if ( !$user->isAllowed( 'move-rootuserpages' )
2104                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
2105                                 // Show user page-specific message only if the user can move other pages
2106                                 $errors[] = [ 'cant-move-user-page' ];
2107                         }
2108
2109                         // Check if user is allowed to move files if it's a file
2110                         if ( $this->mNamespace == NS_FILE && !$user->isAllowed( 'movefile' ) ) {
2111                                 $errors[] = [ 'movenotallowedfile' ];
2112                         }
2113
2114                         // Check if user is allowed to move category pages if it's a category page
2115                         if ( $this->mNamespace == NS_CATEGORY && !$user->isAllowed( 'move-categorypages' ) ) {
2116                                 $errors[] = [ 'cant-move-category-page' ];
2117                         }
2118
2119                         if ( !$user->isAllowed( 'move' ) ) {
2120                                 // User can't move anything
2121                                 $userCanMove = User::groupHasPermission( 'user', 'move' );
2122                                 $autoconfirmedCanMove = User::groupHasPermission( 'autoconfirmed', 'move' );
2123                                 if ( $user->isAnon() && ( $userCanMove || $autoconfirmedCanMove ) ) {
2124                                         // custom message if logged-in users without any special rights can move
2125                                         $errors[] = [ 'movenologintext' ];
2126                                 } else {
2127                                         $errors[] = [ 'movenotallowed' ];
2128                                 }
2129                         }
2130                 } elseif ( $action == 'move-target' ) {
2131                         if ( !$user->isAllowed( 'move' ) ) {
2132                                 // User can't move anything
2133                                 $errors[] = [ 'movenotallowed' ];
2134                         } elseif ( !$user->isAllowed( 'move-rootuserpages' )
2135                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
2136                                 // Show user page-specific message only if the user can move other pages
2137                                 $errors[] = [ 'cant-move-to-user-page' ];
2138                         } elseif ( !$user->isAllowed( 'move-categorypages' )
2139                                         && $this->mNamespace == NS_CATEGORY ) {
2140                                 // Show category page-specific message only if the user can move other pages
2141                                 $errors[] = [ 'cant-move-to-category-page' ];
2142                         }
2143                 } elseif ( !$user->isAllowed( $action ) ) {
2144                         $errors[] = $this->missingPermissionError( $action, $short );
2145                 }
2146
2147                 return $errors;
2148         }
2149
2150         /**
2151          * Add the resulting error code to the errors array
2152          *
2153          * @param array $errors List of current errors
2154          * @param array $result Result of errors
2155          *
2156          * @return array List of errors
2157          */
2158         private function resultToError( $errors, $result ) {
2159                 if ( is_array( $result ) && count( $result ) && !is_array( $result[0] ) ) {
2160                         // A single array representing an error
2161                         $errors[] = $result;
2162                 } elseif ( is_array( $result ) && is_array( $result[0] ) ) {
2163                         // A nested array representing multiple errors
2164                         $errors = array_merge( $errors, $result );
2165                 } elseif ( $result !== '' && is_string( $result ) ) {
2166                         // A string representing a message-id
2167                         $errors[] = [ $result ];
2168                 } elseif ( $result instanceof MessageSpecifier ) {
2169                         // A message specifier representing an error
2170                         $errors[] = [ $result ];
2171                 } elseif ( $result === false ) {
2172                         // a generic "We don't want them to do that"
2173                         $errors[] = [ 'badaccess-group0' ];
2174                 }
2175                 return $errors;
2176         }
2177
2178         /**
2179          * Check various permission hooks
2180          *
2181          * @param string $action The action to check
2182          * @param User $user User to check
2183          * @param array $errors List of current errors
2184          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2185          * @param bool $short Short circuit on first error
2186          *
2187          * @return array List of errors
2188          */
2189         private function checkPermissionHooks( $action, $user, $errors, $rigor, $short ) {
2190                 // Use getUserPermissionsErrors instead
2191                 $result = '';
2192                 // Avoid PHP 7.1 warning from passing $this by reference
2193                 $titleRef = $this;
2194                 if ( !Hooks::run( 'userCan', [ &$titleRef, &$user, $action, &$result ] ) ) {
2195                         return $result ? [] : [ [ 'badaccess-group0' ] ];
2196                 }
2197                 // Check getUserPermissionsErrors hook
2198                 // Avoid PHP 7.1 warning from passing $this by reference
2199                 $titleRef = $this;
2200                 if ( !Hooks::run( 'getUserPermissionsErrors', [ &$titleRef, &$user, $action, &$result ] ) ) {
2201                         $errors = $this->resultToError( $errors, $result );
2202                 }
2203                 // Check getUserPermissionsErrorsExpensive hook
2204                 if (
2205                         $rigor !== 'quick'
2206                         && !( $short && count( $errors ) > 0 )
2207                         && !Hooks::run( 'getUserPermissionsErrorsExpensive', [ &$titleRef, &$user, $action, &$result ] )
2208                 ) {
2209                         $errors = $this->resultToError( $errors, $result );
2210                 }
2211
2212                 return $errors;
2213         }
2214
2215         /**
2216          * Check permissions on special pages & namespaces
2217          *
2218          * @param string $action The action to check
2219          * @param User $user User to check
2220          * @param array $errors List of current errors
2221          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2222          * @param bool $short Short circuit on first error
2223          *
2224          * @return array List of errors
2225          */
2226         private function checkSpecialsAndNSPermissions( $action, $user, $errors, $rigor, $short ) {
2227                 # Only 'createaccount' can be performed on special pages,
2228                 # which don't actually exist in the DB.
2229                 if ( $this->isSpecialPage() && $action !== 'createaccount' ) {
2230                         $errors[] = [ 'ns-specialprotected' ];
2231                 }
2232
2233                 # Check $wgNamespaceProtection for restricted namespaces
2234                 if ( $this->isNamespaceProtected( $user ) ) {
2235                         $ns = $this->mNamespace == NS_MAIN ?
2236                                 wfMessage( 'nstab-main' )->text() : $this->getNsText();
2237                         $errors[] = $this->mNamespace == NS_MEDIAWIKI ?
2238                                 [ 'protectedinterface', $action ] : [ 'namespaceprotected', $ns, $action ];
2239                 }
2240
2241                 return $errors;
2242         }
2243
2244         /**
2245          * Check CSS/JS sub-page permissions
2246          *
2247          * @param string $action The action to check
2248          * @param User $user User to check
2249          * @param array $errors List of current errors
2250          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2251          * @param bool $short Short circuit on first error
2252          *
2253          * @return array List of errors
2254          */
2255         private function checkCSSandJSPermissions( $action, $user, $errors, $rigor, $short ) {
2256                 # Protect css/js subpages of user pages
2257                 # XXX: this might be better using restrictions
2258                 if ( $action != 'patrol' ) {
2259                         if ( preg_match( '/^' . preg_quote( $user->getName(), '/' ) . '\//', $this->mTextform ) ) {
2260                                 if ( $this->isCssSubpage() && !$user->isAllowedAny( 'editmyusercss', 'editusercss' ) ) {
2261                                         $errors[] = [ 'mycustomcssprotected', $action ];
2262                                 } elseif ( $this->isJsSubpage() && !$user->isAllowedAny( 'editmyuserjs', 'edituserjs' ) ) {
2263                                         $errors[] = [ 'mycustomjsprotected', $action ];
2264                                 }
2265                         } else {
2266                                 if ( $this->isCssSubpage() && !$user->isAllowed( 'editusercss' ) ) {
2267                                         $errors[] = [ 'customcssprotected', $action ];
2268                                 } elseif ( $this->isJsSubpage() && !$user->isAllowed( 'edituserjs' ) ) {
2269                                         $errors[] = [ 'customjsprotected', $action ];
2270                                 }
2271                         }
2272                 }
2273
2274                 return $errors;
2275         }
2276
2277         /**
2278          * Check against page_restrictions table requirements on this
2279          * page. The user must possess all required rights for this
2280          * action.
2281          *
2282          * @param string $action The action to check
2283          * @param User $user User to check
2284          * @param array $errors List of current errors
2285          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2286          * @param bool $short Short circuit on first error
2287          *
2288          * @return array List of errors
2289          */
2290         private function checkPageRestrictions( $action, $user, $errors, $rigor, $short ) {
2291                 foreach ( $this->getRestrictions( $action ) as $right ) {
2292                         // Backwards compatibility, rewrite sysop -> editprotected
2293                         if ( $right == 'sysop' ) {
2294                                 $right = 'editprotected';
2295                         }
2296                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2297                         if ( $right == 'autoconfirmed' ) {
2298                                 $right = 'editsemiprotected';
2299                         }
2300                         if ( $right == '' ) {
2301                                 continue;
2302                         }
2303                         if ( !$user->isAllowed( $right ) ) {
2304                                 $errors[] = [ 'protectedpagetext', $right, $action ];
2305                         } elseif ( $this->mCascadeRestriction && !$user->isAllowed( 'protect' ) ) {
2306                                 $errors[] = [ 'protectedpagetext', 'protect', $action ];
2307                         }
2308                 }
2309
2310                 return $errors;
2311         }
2312
2313         /**
2314          * Check restrictions on cascading pages.
2315          *
2316          * @param string $action The action to check
2317          * @param User $user User to check
2318          * @param array $errors List of current errors
2319          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2320          * @param bool $short Short circuit on first error
2321          *
2322          * @return array List of errors
2323          */
2324         private function checkCascadingSourcesRestrictions( $action, $user, $errors, $rigor, $short ) {
2325                 if ( $rigor !== 'quick' && !$this->isCssJsSubpage() ) {
2326                         # We /could/ use the protection level on the source page, but it's
2327                         # fairly ugly as we have to establish a precedence hierarchy for pages
2328                         # included by multiple cascade-protected pages. So just restrict
2329                         # it to people with 'protect' permission, as they could remove the
2330                         # protection anyway.
2331                         list( $cascadingSources, $restrictions ) = $this->getCascadeProtectionSources();
2332                         # Cascading protection depends on more than this page...
2333                         # Several cascading protected pages may include this page...
2334                         # Check each cascading level
2335                         # This is only for protection restrictions, not for all actions
2336                         if ( isset( $restrictions[$action] ) ) {
2337                                 foreach ( $restrictions[$action] as $right ) {
2338                                         // Backwards compatibility, rewrite sysop -> editprotected
2339                                         if ( $right == 'sysop' ) {
2340                                                 $right = 'editprotected';
2341                                         }
2342                                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2343                                         if ( $right == 'autoconfirmed' ) {
2344                                                 $right = 'editsemiprotected';
2345                                         }
2346                                         if ( $right != '' && !$user->isAllowedAll( 'protect', $right ) ) {
2347                                                 $pages = '';
2348                                                 foreach ( $cascadingSources as $page ) {
2349                                                         $pages .= '* [[:' . $page->getPrefixedText() . "]]\n";
2350                                                 }
2351                                                 $errors[] = [ 'cascadeprotected', count( $cascadingSources ), $pages, $action ];
2352                                         }
2353                                 }
2354                         }
2355                 }
2356
2357                 return $errors;
2358         }
2359
2360         /**
2361          * Check action permissions not already checked in checkQuickPermissions
2362          *
2363          * @param string $action The action to check
2364          * @param User $user User to check
2365          * @param array $errors List of current errors
2366          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2367          * @param bool $short Short circuit on first error
2368          *
2369          * @return array List of errors
2370          */
2371         private function checkActionPermissions( $action, $user, $errors, $rigor, $short ) {
2372                 global $wgDeleteRevisionsLimit, $wgLang;
2373
2374                 if ( $action == 'protect' ) {
2375                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit', $user, $rigor, true ) ) ) {
2376                                 // If they can't edit, they shouldn't protect.
2377                                 $errors[] = [ 'protect-cantedit' ];
2378                         }
2379                 } elseif ( $action == 'create' ) {
2380                         $title_protection = $this->getTitleProtection();
2381                         if ( $title_protection ) {
2382                                 if ( $title_protection['permission'] == ''
2383                                         || !$user->isAllowed( $title_protection['permission'] )
2384                                 ) {
2385                                         $errors[] = [
2386                                                 'titleprotected',
2387                                                 User::whoIs( $title_protection['user'] ),
2388                                                 $title_protection['reason']
2389                                         ];
2390                                 }
2391                         }
2392                 } elseif ( $action == 'move' ) {
2393                         // Check for immobile pages
2394                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2395                                 // Specific message for this case
2396                                 $errors[] = [ 'immobile-source-namespace', $this->getNsText() ];
2397                         } elseif ( !$this->isMovable() ) {
2398                                 // Less specific message for rarer cases
2399                                 $errors[] = [ 'immobile-source-page' ];
2400                         }
2401                 } elseif ( $action == 'move-target' ) {
2402                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2403                                 $errors[] = [ 'immobile-target-namespace', $this->getNsText() ];
2404                         } elseif ( !$this->isMovable() ) {
2405                                 $errors[] = [ 'immobile-target-page' ];
2406                         }
2407                 } elseif ( $action == 'delete' ) {
2408                         $tempErrors = $this->checkPageRestrictions( 'edit', $user, [], $rigor, true );
2409                         if ( !$tempErrors ) {
2410                                 $tempErrors = $this->checkCascadingSourcesRestrictions( 'edit',
2411                                         $user, $tempErrors, $rigor, true );
2412                         }
2413                         if ( $tempErrors ) {
2414                                 // If protection keeps them from editing, they shouldn't be able to delete.
2415                                 $errors[] = [ 'deleteprotected' ];
2416                         }
2417                         if ( $rigor !== 'quick' && $wgDeleteRevisionsLimit
2418                                 && !$this->userCan( 'bigdelete', $user ) && $this->isBigDeletion()
2419                         ) {
2420                                 $errors[] = [ 'delete-toobig', $wgLang->formatNum( $wgDeleteRevisionsLimit ) ];
2421                         }
2422                 } elseif ( $action === 'undelete' ) {
2423                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit', $user, $rigor, true ) ) ) {
2424                                 // Undeleting implies editing
2425                                 $errors[] = [ 'undelete-cantedit' ];
2426                         }
2427                         if ( !$this->exists()
2428                                 && count( $this->getUserPermissionsErrorsInternal( 'create', $user, $rigor, true ) )
2429                         ) {
2430                                 // Undeleting where nothing currently exists implies creating
2431                                 $errors[] = [ 'undelete-cantcreate' ];
2432                         }
2433                 }
2434                 return $errors;
2435         }
2436
2437         /**
2438          * Check that the user isn't blocked from editing.
2439          *
2440          * @param string $action The action to check
2441          * @param User $user User to check
2442          * @param array $errors List of current errors
2443          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2444          * @param bool $short Short circuit on first error
2445          *
2446          * @return array List of errors
2447          */
2448         private function checkUserBlock( $action, $user, $errors, $rigor, $short ) {
2449                 global $wgEmailConfirmToEdit, $wgBlockDisablesLogin;
2450                 // Account creation blocks handled at userlogin.
2451                 // Unblocking handled in SpecialUnblock
2452                 if ( $rigor === 'quick' || in_array( $action, [ 'createaccount', 'unblock' ] ) ) {
2453                         return $errors;
2454                 }
2455
2456                 // Optimize for a very common case
2457                 if ( $action === 'read' && !$wgBlockDisablesLogin ) {
2458                         return $errors;
2459                 }
2460
2461                 if ( $wgEmailConfirmToEdit && !$user->isEmailConfirmed() ) {
2462                         $errors[] = [ 'confirmedittext' ];
2463                 }
2464
2465                 $useSlave = ( $rigor !== 'secure' );
2466                 if ( ( $action == 'edit' || $action == 'create' )
2467                         && !$user->isBlockedFrom( $this, $useSlave )
2468                 ) {
2469                         // Don't block the user from editing their own talk page unless they've been
2470                         // explicitly blocked from that too.
2471                 } elseif ( $user->isBlocked() && $user->getBlock()->prevents( $action ) !== false ) {
2472                         // @todo FIXME: Pass the relevant context into this function.
2473                         $errors[] = $user->getBlock()->getPermissionsError( RequestContext::getMain() );
2474                 }
2475
2476                 return $errors;
2477         }
2478
2479         /**
2480          * Check that the user is allowed to read this page.
2481          *
2482          * @param string $action The action to check
2483          * @param User $user User to check
2484          * @param array $errors List of current errors
2485          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2486          * @param bool $short Short circuit on first error
2487          *
2488          * @return array List of errors
2489          */
2490         private function checkReadPermissions( $action, $user, $errors, $rigor, $short ) {
2491                 global $wgWhitelistRead, $wgWhitelistReadRegexp;
2492
2493                 $whitelisted = false;
2494                 if ( User::isEveryoneAllowed( 'read' ) ) {
2495                         # Shortcut for public wikis, allows skipping quite a bit of code
2496                         $whitelisted = true;
2497                 } elseif ( $user->isAllowed( 'read' ) ) {
2498                         # If the user is allowed to read pages, he is allowed to read all pages
2499                         $whitelisted = true;
2500                 } elseif ( $this->isSpecial( 'Userlogin' )
2501                         || $this->isSpecial( 'PasswordReset' )
2502                         || $this->isSpecial( 'Userlogout' )
2503                 ) {
2504                         # Always grant access to the login page.
2505                         # Even anons need to be able to log in.
2506                         $whitelisted = true;
2507                 } elseif ( is_array( $wgWhitelistRead ) && count( $wgWhitelistRead ) ) {
2508                         # Time to check the whitelist
2509                         # Only do these checks is there's something to check against
2510                         $name = $this->getPrefixedText();
2511                         $dbName = $this->getPrefixedDBkey();
2512
2513                         // Check for explicit whitelisting with and without underscores
2514                         if ( in_array( $name, $wgWhitelistRead, true ) || in_array( $dbName, $wgWhitelistRead, true ) ) {
2515                                 $whitelisted = true;
2516                         } elseif ( $this->getNamespace() == NS_MAIN ) {
2517                                 # Old settings might have the title prefixed with
2518                                 # a colon for main-namespace pages
2519                                 if ( in_array( ':' . $name, $wgWhitelistRead ) ) {
2520                                         $whitelisted = true;
2521                                 }
2522                         } elseif ( $this->isSpecialPage() ) {
2523                                 # If it's a special page, ditch the subpage bit and check again
2524                                 $name = $this->getDBkey();
2525                                 list( $name, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $name );
2526                                 if ( $name ) {
2527                                         $pure = SpecialPage::getTitleFor( $name )->getPrefixedText();
2528                                         if ( in_array( $pure, $wgWhitelistRead, true ) ) {
2529                                                 $whitelisted = true;
2530                                         }
2531                                 }
2532                         }
2533                 }
2534
2535                 if ( !$whitelisted && is_array( $wgWhitelistReadRegexp ) && !empty( $wgWhitelistReadRegexp ) ) {
2536                         $name = $this->getPrefixedText();
2537                         // Check for regex whitelisting
2538                         foreach ( $wgWhitelistReadRegexp as $listItem ) {
2539                                 if ( preg_match( $listItem, $name ) ) {
2540                                         $whitelisted = true;
2541                                         break;
2542                                 }
2543                         }
2544                 }
2545
2546                 if ( !$whitelisted ) {
2547                         # If the title is not whitelisted, give extensions a chance to do so...
2548                         Hooks::run( 'TitleReadWhitelist', [ $this, $user, &$whitelisted ] );
2549                         if ( !$whitelisted ) {
2550                                 $errors[] = $this->missingPermissionError( $action, $short );
2551                         }
2552                 }
2553
2554                 return $errors;
2555         }
2556
2557         /**
2558          * Get a description array when the user doesn't have the right to perform
2559          * $action (i.e. when User::isAllowed() returns false)
2560          *
2561          * @param string $action The action to check
2562          * @param bool $short Short circuit on first error
2563          * @return array Array containing an error message key and any parameters
2564          */
2565         private function missingPermissionError( $action, $short ) {
2566                 // We avoid expensive display logic for quickUserCan's and such
2567                 if ( $short ) {
2568                         return [ 'badaccess-group0' ];
2569                 }
2570
2571                 return User::newFatalPermissionDeniedStatus( $action )->getErrorsArray()[0];
2572         }
2573
2574         /**
2575          * Can $user perform $action on this page? This is an internal function,
2576          * with multiple levels of checks depending on performance needs; see $rigor below.
2577          * It does not check wfReadOnly().
2578          *
2579          * @param string $action Action that permission needs to be checked for
2580          * @param User $user User to check
2581          * @param string $rigor One of (quick,full,secure)
2582          *   - quick  : does cheap permission checks from replica DBs (usable for GUI creation)
2583          *   - full   : does cheap and expensive checks possibly from a replica DB
2584          *   - secure : does cheap and expensive checks, using the master as needed
2585          * @param bool $short Set this to true to stop after the first permission error.
2586          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
2587          */
2588         protected function getUserPermissionsErrorsInternal(
2589                 $action, $user, $rigor = 'secure', $short = false
2590         ) {
2591                 if ( $rigor === true ) {
2592                         $rigor = 'secure'; // b/c
2593                 } elseif ( $rigor === false ) {
2594                         $rigor = 'quick'; // b/c
2595                 } elseif ( !in_array( $rigor, [ 'quick', 'full', 'secure' ] ) ) {
2596                         throw new Exception( "Invalid rigor parameter '$rigor'." );
2597                 }
2598
2599                 # Read has special handling
2600                 if ( $action == 'read' ) {
2601                         $checks = [
2602                                 'checkPermissionHooks',
2603                                 'checkReadPermissions',
2604                                 'checkUserBlock', // for wgBlockDisablesLogin
2605                         ];
2606                 # Don't call checkSpecialsAndNSPermissions or checkCSSandJSPermissions
2607                 # here as it will lead to duplicate error messages. This is okay to do
2608                 # since anywhere that checks for create will also check for edit, and
2609                 # those checks are called for edit.
2610                 } elseif ( $action == 'create' ) {
2611                         $checks = [
2612                                 'checkQuickPermissions',
2613                                 'checkPermissionHooks',
2614                                 'checkPageRestrictions',
2615                                 'checkCascadingSourcesRestrictions',
2616                                 'checkActionPermissions',
2617                                 'checkUserBlock'
2618                         ];
2619                 } else {
2620                         $checks = [
2621                                 'checkQuickPermissions',
2622                                 'checkPermissionHooks',
2623                                 'checkSpecialsAndNSPermissions',
2624                                 'checkCSSandJSPermissions',
2625                                 'checkPageRestrictions',
2626                                 'checkCascadingSourcesRestrictions',
2627                                 'checkActionPermissions',
2628                                 'checkUserBlock'
2629                         ];
2630                 }
2631
2632                 $errors = [];
2633                 while ( count( $checks ) > 0 &&
2634                                 !( $short && count( $errors ) > 0 ) ) {
2635                         $method = array_shift( $checks );
2636                         $errors = $this->$method( $action, $user, $errors, $rigor, $short );
2637                 }
2638
2639                 return $errors;
2640         }
2641
2642         /**
2643          * Get a filtered list of all restriction types supported by this wiki.
2644          * @param bool $exists True to get all restriction types that apply to
2645          * titles that do exist, False for all restriction types that apply to
2646          * titles that do not exist
2647          * @return array
2648          */
2649         public static function getFilteredRestrictionTypes( $exists = true ) {
2650                 global $wgRestrictionTypes;
2651                 $types = $wgRestrictionTypes;
2652                 if ( $exists ) {
2653                         # Remove the create restriction for existing titles
2654                         $types = array_diff( $types, [ 'create' ] );
2655                 } else {
2656                         # Only the create and upload restrictions apply to non-existing titles
2657                         $types = array_intersect( $types, [ 'create', 'upload' ] );
2658                 }
2659                 return $types;
2660         }
2661
2662         /**
2663          * Returns restriction types for the current Title
2664          *
2665          * @return array Applicable restriction types
2666          */
2667         public function getRestrictionTypes() {
2668                 if ( $this->isSpecialPage() ) {
2669                         return [];
2670                 }
2671
2672                 $types = self::getFilteredRestrictionTypes( $this->exists() );
2673
2674                 if ( $this->getNamespace() != NS_FILE ) {
2675                         # Remove the upload restriction for non-file titles
2676                         $types = array_diff( $types, [ 'upload' ] );
2677                 }
2678
2679                 Hooks::run( 'TitleGetRestrictionTypes', [ $this, &$types ] );
2680
2681                 wfDebug( __METHOD__ . ': applicable restrictions to [[' .
2682                         $this->getPrefixedText() . ']] are {' . implode( ',', $types ) . "}\n" );
2683
2684                 return $types;
2685         }
2686
2687         /**
2688          * Is this title subject to title protection?
2689          * Title protection is the one applied against creation of such title.
2690          *
2691          * @return array|bool An associative array representing any existent title
2692          *   protection, or false if there's none.
2693          */
2694         public function getTitleProtection() {
2695                 $protection = $this->getTitleProtectionInternal();
2696                 if ( $protection ) {
2697                         if ( $protection['permission'] == 'sysop' ) {
2698                                 $protection['permission'] = 'editprotected'; // B/C
2699                         }
2700                         if ( $protection['permission'] == 'autoconfirmed' ) {
2701                                 $protection['permission'] = 'editsemiprotected'; // B/C
2702                         }
2703                 }
2704                 return $protection;
2705         }
2706
2707         /**
2708          * Fetch title protection settings
2709          *
2710          * To work correctly, $this->loadRestrictions() needs to have access to the
2711          * actual protections in the database without munging 'sysop' =>
2712          * 'editprotected' and 'autoconfirmed' => 'editsemiprotected'. Other
2713          * callers probably want $this->getTitleProtection() instead.
2714          *
2715          * @return array|bool
2716          */
2717         protected function getTitleProtectionInternal() {
2718                 // Can't protect pages in special namespaces
2719                 if ( $this->getNamespace() < 0 ) {
2720                         return false;
2721                 }
2722
2723                 // Can't protect pages that exist.
2724                 if ( $this->exists() ) {
2725                         return false;
2726                 }
2727
2728                 if ( $this->mTitleProtection === null ) {
2729                         $dbr = wfGetDB( DB_REPLICA );
2730                         $commentStore = new CommentStore( 'pt_reason' );
2731                         $commentQuery = $commentStore->getJoin();
2732                         $res = $dbr->select(
2733                                 [ 'protected_titles' ] + $commentQuery['tables'],
2734                                 [
2735                                         'user' => 'pt_user',
2736                                         'expiry' => 'pt_expiry',
2737                                         'permission' => 'pt_create_perm'
2738                                 ] + $commentQuery['fields'],
2739                                 [ 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ],
2740                                 __METHOD__,
2741                                 [],
2742                                 $commentQuery['joins']
2743                         );
2744
2745                         // fetchRow returns false if there are no rows.
2746                         $row = $dbr->fetchRow( $res );
2747                         if ( $row ) {
2748                                 $this->mTitleProtection = [
2749                                         'user' => $row['user'],
2750                                         'expiry' => $dbr->decodeExpiry( $row['expiry'] ),
2751                                         'permission' => $row['permission'],
2752                                         'reason' => $commentStore->getComment( $row )->text,
2753                                 ];
2754                         } else {
2755                                 $this->mTitleProtection = false;
2756                         }
2757                 }
2758                 return $this->mTitleProtection;
2759         }
2760
2761         /**
2762          * Remove any title protection due to page existing
2763          */
2764         public function deleteTitleProtection() {
2765                 $dbw = wfGetDB( DB_MASTER );
2766
2767                 $dbw->delete(
2768                         'protected_titles',
2769                         [ 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ],
2770                         __METHOD__
2771                 );
2772                 $this->mTitleProtection = false;
2773         }
2774
2775         /**
2776          * Is this page "semi-protected" - the *only* protection levels are listed
2777          * in $wgSemiprotectedRestrictionLevels?
2778          *
2779          * @param string $action Action to check (default: edit)
2780          * @return bool
2781          */
2782         public function isSemiProtected( $action = 'edit' ) {
2783                 global $wgSemiprotectedRestrictionLevels;
2784
2785                 $restrictions = $this->getRestrictions( $action );
2786                 $semi = $wgSemiprotectedRestrictionLevels;
2787                 if ( !$restrictions || !$semi ) {
2788                         // Not protected, or all protection is full protection
2789                         return false;
2790                 }
2791
2792                 // Remap autoconfirmed to editsemiprotected for BC
2793                 foreach ( array_keys( $semi, 'autoconfirmed' ) as $key ) {
2794                         $semi[$key] = 'editsemiprotected';
2795                 }
2796                 foreach ( array_keys( $restrictions, 'autoconfirmed' ) as $key ) {
2797                         $restrictions[$key] = 'editsemiprotected';
2798                 }
2799
2800                 return !array_diff( $restrictions, $semi );
2801         }
2802
2803         /**
2804          * Does the title correspond to a protected article?
2805          *
2806          * @param string $action The action the page is protected from,
2807          * by default checks all actions.
2808          * @return bool
2809          */
2810         public function isProtected( $action = '' ) {
2811                 global $wgRestrictionLevels;
2812
2813                 $restrictionTypes = $this->getRestrictionTypes();
2814
2815                 # Special pages have inherent protection
2816                 if ( $this->isSpecialPage() ) {
2817                         return true;
2818                 }
2819
2820                 # Check regular protection levels
2821                 foreach ( $restrictionTypes as $type ) {
2822                         if ( $action == $type || $action == '' ) {
2823                                 $r = $this->getRestrictions( $type );
2824                                 foreach ( $wgRestrictionLevels as $level ) {
2825                                         if ( in_array( $level, $r ) && $level != '' ) {
2826                                                 return true;
2827                                         }
2828                                 }
2829                         }
2830                 }
2831
2832                 return false;
2833         }
2834
2835         /**
2836          * Determines if $user is unable to edit this page because it has been protected
2837          * by $wgNamespaceProtection.
2838          *
2839          * @param User $user User object to check permissions
2840          * @return bool
2841          */
2842         public function isNamespaceProtected( User $user ) {
2843                 global $wgNamespaceProtection;
2844
2845                 if ( isset( $wgNamespaceProtection[$this->mNamespace] ) ) {
2846                         foreach ( (array)$wgNamespaceProtection[$this->mNamespace] as $right ) {
2847                                 if ( $right != '' && !$user->isAllowed( $right ) ) {
2848                                         return true;
2849                                 }
2850                         }
2851                 }
2852                 return false;
2853         }
2854
2855         /**
2856          * Cascading protection: Return true if cascading restrictions apply to this page, false if not.
2857          *
2858          * @return bool If the page is subject to cascading restrictions.
2859          */
2860         public function isCascadeProtected() {
2861                 list( $sources, /* $restrictions */ ) = $this->getCascadeProtectionSources( false );
2862                 return ( $sources > 0 );
2863         }
2864
2865         /**
2866          * Determines whether cascading protection sources have already been loaded from
2867          * the database.
2868          *
2869          * @param bool $getPages True to check if the pages are loaded, or false to check
2870          * if the status is loaded.
2871          * @return bool Whether or not the specified information has been loaded
2872          * @since 1.23
2873          */
2874         public function areCascadeProtectionSourcesLoaded( $getPages = true ) {
2875                 return $getPages ? $this->mCascadeSources !== null : $this->mHasCascadingRestrictions !== null;
2876         }
2877
2878         /**
2879          * Cascading protection: Get the source of any cascading restrictions on this page.
2880          *
2881          * @param bool $getPages Whether or not to retrieve the actual pages
2882          *        that the restrictions have come from and the actual restrictions
2883          *        themselves.
2884          * @return array Two elements: First is an array of Title objects of the
2885          *        pages from which cascading restrictions have come, false for
2886          *        none, or true if such restrictions exist but $getPages was not
2887          *        set. Second is an array like that returned by
2888          *        Title::getAllRestrictions(), or an empty array if $getPages is
2889          *        false.
2890          */
2891         public function getCascadeProtectionSources( $getPages = true ) {
2892                 $pagerestrictions = [];
2893
2894                 if ( $this->mCascadeSources !== null && $getPages ) {
2895                         return [ $this->mCascadeSources, $this->mCascadingRestrictions ];
2896                 } elseif ( $this->mHasCascadingRestrictions !== null && !$getPages ) {
2897                         return [ $this->mHasCascadingRestrictions, $pagerestrictions ];
2898                 }
2899
2900                 $dbr = wfGetDB( DB_REPLICA );
2901
2902                 if ( $this->getNamespace() == NS_FILE ) {
2903                         $tables = [ 'imagelinks', 'page_restrictions' ];
2904                         $where_clauses = [
2905                                 'il_to' => $this->getDBkey(),
2906                                 'il_from=pr_page',
2907                                 'pr_cascade' => 1
2908                         ];
2909                 } else {
2910                         $tables = [ 'templatelinks', 'page_restrictions' ];
2911                         $where_clauses = [
2912                                 'tl_namespace' => $this->getNamespace(),
2913                                 'tl_title' => $this->getDBkey(),
2914                                 'tl_from=pr_page',
2915                                 'pr_cascade' => 1
2916                         ];
2917                 }
2918
2919                 if ( $getPages ) {
2920                         $cols = [ 'pr_page', 'page_namespace', 'page_title',
2921                                 'pr_expiry', 'pr_type', 'pr_level' ];
2922                         $where_clauses[] = 'page_id=pr_page';
2923                         $tables[] = 'page';
2924                 } else {
2925                         $cols = [ 'pr_expiry' ];
2926                 }
2927
2928                 $res = $dbr->select( $tables, $cols, $where_clauses, __METHOD__ );
2929
2930                 $sources = $getPages ? [] : false;
2931                 $now = wfTimestampNow();
2932
2933                 foreach ( $res as $row ) {
2934                         $expiry = $dbr->decodeExpiry( $row->pr_expiry );
2935                         if ( $expiry > $now ) {
2936                                 if ( $getPages ) {
2937                                         $page_id = $row->pr_page;
2938                                         $page_ns = $row->page_namespace;
2939                                         $page_title = $row->page_title;
2940                                         $sources[$page_id] = self::makeTitle( $page_ns, $page_title );
2941                                         # Add groups needed for each restriction type if its not already there
2942                                         # Make sure this restriction type still exists
2943
2944                                         if ( !isset( $pagerestrictions[$row->pr_type] ) ) {
2945                                                 $pagerestrictions[$row->pr_type] = [];
2946                                         }
2947
2948                                         if (
2949                                                 isset( $pagerestrictions[$row->pr_type] )
2950                                                 && !in_array( $row->pr_level, $pagerestrictions[$row->pr_type] )
2951                                         ) {
2952                                                 $pagerestrictions[$row->pr_type][] = $row->pr_level;
2953                                         }
2954                                 } else {
2955                                         $sources = true;
2956                                 }
2957                         }
2958                 }
2959
2960                 if ( $getPages ) {
2961                         $this->mCascadeSources = $sources;
2962                         $this->mCascadingRestrictions = $pagerestrictions;
2963                 } else {
2964                         $this->mHasCascadingRestrictions = $sources;
2965                 }
2966
2967                 return [ $sources, $pagerestrictions ];
2968         }
2969
2970         /**
2971          * Accessor for mRestrictionsLoaded
2972          *
2973          * @return bool Whether or not the page's restrictions have already been
2974          * loaded from the database
2975          * @since 1.23
2976          */
2977         public function areRestrictionsLoaded() {
2978                 return $this->mRestrictionsLoaded;
2979         }
2980
2981         /**
2982          * Accessor/initialisation for mRestrictions
2983          *
2984          * @param string $action Action that permission needs to be checked for
2985          * @return array Restriction levels needed to take the action. All levels are
2986          *     required. Note that restriction levels are normally user rights, but 'sysop'
2987          *     and 'autoconfirmed' are also allowed for backwards compatibility. These should
2988          *     be mapped to 'editprotected' and 'editsemiprotected' respectively.
2989          */
2990         public function getRestrictions( $action ) {
2991                 if ( !$this->mRestrictionsLoaded ) {
2992                         $this->loadRestrictions();
2993                 }
2994                 return isset( $this->mRestrictions[$action] )
2995                                 ? $this->mRestrictions[$action]
2996                                 : [];
2997         }
2998
2999         /**
3000          * Accessor/initialisation for mRestrictions
3001          *
3002          * @return array Keys are actions, values are arrays as returned by
3003          *     Title::getRestrictions()
3004          * @since 1.23
3005          */
3006         public function getAllRestrictions() {
3007                 if ( !$this->mRestrictionsLoaded ) {
3008                         $this->loadRestrictions();
3009                 }
3010                 return $this->mRestrictions;
3011         }
3012
3013         /**
3014          * Get the expiry time for the restriction against a given action
3015          *
3016          * @param string $action
3017          * @return string|bool 14-char timestamp, or 'infinity' if the page is protected forever
3018          *     or not protected at all, or false if the action is not recognised.
3019          */
3020         public function getRestrictionExpiry( $action ) {
3021                 if ( !$this->mRestrictionsLoaded ) {
3022                         $this->loadRestrictions();
3023                 }
3024                 return isset( $this->mRestrictionsExpiry[$action] ) ? $this->mRestrictionsExpiry[$action] : false;
3025         }
3026
3027         /**
3028          * Returns cascading restrictions for the current article
3029          *
3030          * @return bool
3031          */
3032         function areRestrictionsCascading() {
3033                 if ( !$this->mRestrictionsLoaded ) {
3034                         $this->loadRestrictions();
3035                 }
3036
3037                 return $this->mCascadeRestriction;
3038         }
3039
3040         /**
3041          * Compiles list of active page restrictions from both page table (pre 1.10)
3042          * and page_restrictions table for this existing page.
3043          * Public for usage by LiquidThreads.
3044          *
3045          * @param array $rows Array of db result objects
3046          * @param string $oldFashionedRestrictions Comma-separated list of page
3047          *   restrictions from page table (pre 1.10)
3048          */
3049         public function loadRestrictionsFromRows( $rows, $oldFashionedRestrictions = null ) {
3050                 $dbr = wfGetDB( DB_REPLICA );
3051
3052                 $restrictionTypes = $this->getRestrictionTypes();
3053
3054                 foreach ( $restrictionTypes as $type ) {
3055                         $this->mRestrictions[$type] = [];
3056                         $this->mRestrictionsExpiry[$type] = 'infinity';
3057                 }
3058
3059                 $this->mCascadeRestriction = false;
3060
3061                 # Backwards-compatibility: also load the restrictions from the page record (old format).
3062                 if ( $oldFashionedRestrictions !== null ) {
3063                         $this->mOldRestrictions = $oldFashionedRestrictions;
3064                 }
3065
3066                 if ( $this->mOldRestrictions === false ) {
3067                         $this->mOldRestrictions = $dbr->selectField( 'page', 'page_restrictions',
3068                                 [ 'page_id' => $this->getArticleID() ], __METHOD__ );
3069                 }
3070
3071                 if ( $this->mOldRestrictions != '' ) {
3072                         foreach ( explode( ':', trim( $this->mOldRestrictions ) ) as $restrict ) {
3073                                 $temp = explode( '=', trim( $restrict ) );
3074                                 if ( count( $temp ) == 1 ) {
3075                                         // old old format should be treated as edit/move restriction
3076                                         $this->mRestrictions['edit'] = explode( ',', trim( $temp[0] ) );
3077                                         $this->mRestrictions['move'] = explode( ',', trim( $temp[0] ) );
3078                                 } else {
3079                                         $restriction = trim( $temp[1] );
3080                                         if ( $restriction != '' ) { // some old entries are empty
3081                                                 $this->mRestrictions[$temp[0]] = explode( ',', $restriction );
3082                                         }
3083                                 }
3084                         }
3085                 }
3086
3087                 if ( count( $rows ) ) {
3088                         # Current system - load second to make them override.
3089                         $now = wfTimestampNow();
3090
3091                         # Cycle through all the restrictions.
3092                         foreach ( $rows as $row ) {
3093                                 // Don't take care of restrictions types that aren't allowed
3094                                 if ( !in_array( $row->pr_type, $restrictionTypes ) ) {
3095                                         continue;
3096                                 }
3097
3098                                 $expiry = $dbr->decodeExpiry( $row->pr_expiry );
3099
3100                                 // Only apply the restrictions if they haven't expired!
3101                                 if ( !$expiry || $expiry > $now ) {
3102                                         $this->mRestrictionsExpiry[$row->pr_type] = $expiry;
3103                                         $this->mRestrictions[$row->pr_type] = explode( ',', trim( $row->pr_level ) );
3104
3105                                         $this->mCascadeRestriction |= $row->pr_cascade;
3106                                 }
3107                         }
3108                 }
3109
3110                 $this->mRestrictionsLoaded = true;
3111         }
3112
3113         /**
3114          * Load restrictions from the page_restrictions table
3115          *
3116          * @param string $oldFashionedRestrictions Comma-separated list of page
3117          *   restrictions from page table (pre 1.10)
3118          */
3119         public function loadRestrictions( $oldFashionedRestrictions = null ) {
3120                 if ( $this->mRestrictionsLoaded ) {
3121                         return;
3122                 }
3123
3124                 $id = $this->getArticleID();
3125                 if ( $id ) {
3126                         $cache = ObjectCache::getMainWANInstance();
3127                         $rows = $cache->getWithSetCallback(
3128                                 // Page protections always leave a new null revision
3129                                 $cache->makeKey( 'page-restrictions', $id, $this->getLatestRevID() ),
3130                                 $cache::TTL_DAY,
3131                                 function ( $curValue, &$ttl, array &$setOpts ) {
3132                                         $dbr = wfGetDB( DB_REPLICA );
3133
3134                                         $setOpts += Database::getCacheSetOptions( $dbr );
3135
3136                                         return iterator_to_array(
3137                                                 $dbr->select(
3138                                                         'page_restrictions',
3139                                                         [ 'pr_type', 'pr_expiry', 'pr_level', 'pr_cascade' ],
3140                                                         [ 'pr_page' => $this->getArticleID() ],
3141                                                         __METHOD__
3142                                                 )
3143                                         );
3144                                 }
3145                         );
3146
3147                         $this->loadRestrictionsFromRows( $rows, $oldFashionedRestrictions );
3148                 } else {
3149                         $title_protection = $this->getTitleProtectionInternal();
3150
3151                         if ( $title_protection ) {
3152                                 $now = wfTimestampNow();
3153                                 $expiry = wfGetDB( DB_REPLICA )->decodeExpiry( $title_protection['expiry'] );
3154
3155                                 if ( !$expiry || $expiry > $now ) {
3156                                         // Apply the restrictions
3157                                         $this->mRestrictionsExpiry['create'] = $expiry;
3158                                         $this->mRestrictions['create'] =
3159                                                 explode( ',', trim( $title_protection['permission'] ) );
3160                                 } else { // Get rid of the old restrictions
3161                                         $this->mTitleProtection = false;
3162                                 }
3163                         } else {
3164                                 $this->mRestrictionsExpiry['create'] = 'infinity';
3165                         }
3166                         $this->mRestrictionsLoaded = true;
3167                 }
3168         }
3169
3170         /**
3171          * Flush the protection cache in this object and force reload from the database.
3172          * This is used when updating protection from WikiPage::doUpdateRestrictions().
3173          */
3174         public function flushRestrictions() {
3175                 $this->mRestrictionsLoaded = false;
3176                 $this->mTitleProtection = null;
3177         }
3178
3179         /**
3180          * Purge expired restrictions from the page_restrictions table
3181          *
3182          * This will purge no more than $wgUpdateRowsPerQuery page_restrictions rows
3183          */
3184         static function purgeExpiredRestrictions() {
3185                 if ( wfReadOnly() ) {
3186                         return;
3187                 }
3188
3189                 DeferredUpdates::addUpdate( new AtomicSectionUpdate(
3190                         wfGetDB( DB_MASTER ),
3191                         __METHOD__,
3192                         function ( IDatabase $dbw, $fname ) {
3193                                 $config = MediaWikiServices::getInstance()->getMainConfig();
3194                                 $ids = $dbw->selectFieldValues(
3195                                         'page_restrictions',
3196                                         'pr_id',
3197                                         [ 'pr_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ],
3198                                         $fname,
3199                                         [ 'LIMIT' => $config->get( 'UpdateRowsPerQuery' ) ] // T135470
3200                                 );
3201                                 if ( $ids ) {
3202                                         $dbw->delete( 'page_restrictions', [ 'pr_id' => $ids ], $fname );
3203                                 }
3204                         }
3205                 ) );
3206
3207                 DeferredUpdates::addUpdate( new AtomicSectionUpdate(
3208                         wfGetDB( DB_MASTER ),
3209                         __METHOD__,
3210                         function ( IDatabase $dbw, $fname ) {
3211                                 $dbw->delete(
3212                                         'protected_titles',
3213                                         [ 'pt_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ],
3214                                         $fname
3215                                 );
3216                         }
3217                 ) );
3218         }
3219
3220         /**
3221          * Does this have subpages?  (Warning, usually requires an extra DB query.)
3222          *
3223          * @return bool
3224          */
3225         public function hasSubpages() {
3226                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
3227                         # Duh
3228                         return false;
3229                 }
3230
3231                 # We dynamically add a member variable for the purpose of this method
3232                 # alone to cache the result.  There's no point in having it hanging
3233                 # around uninitialized in every Title object; therefore we only add it
3234                 # if needed and don't declare it statically.
3235                 if ( $this->mHasSubpages === null ) {
3236                         $this->mHasSubpages = false;
3237                         $subpages = $this->getSubpages( 1 );
3238                         if ( $subpages instanceof TitleArray ) {
3239                                 $this->mHasSubpages = (bool)$subpages->count();
3240                         }
3241                 }
3242
3243                 return $this->mHasSubpages;
3244         }
3245
3246         /**
3247          * Get all subpages of this page.
3248          *
3249          * @param int $limit Maximum number of subpages to fetch; -1 for no limit
3250          * @return TitleArray|array TitleArray, or empty array if this page's namespace
3251          *  doesn't allow subpages
3252          */
3253         public function getSubpages( $limit = -1 ) {
3254                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3255                         return [];
3256                 }
3257
3258                 $dbr = wfGetDB( DB_REPLICA );
3259                 $conds['page_namespace'] = $this->getNamespace();
3260                 $conds[] = 'page_title ' . $dbr->buildLike( $this->getDBkey() . '/', $dbr->anyString() );
3261                 $options = [];
3262                 if ( $limit > -1 ) {
3263                         $options['LIMIT'] = $limit;
3264                 }
3265                 return TitleArray::newFromResult(
3266                         $dbr->select( 'page',
3267                                 [ 'page_id', 'page_namespace', 'page_title', 'page_is_redirect' ],
3268                                 $conds,
3269                                 __METHOD__,
3270                                 $options
3271                         )
3272                 );
3273         }
3274
3275         /**
3276          * Is there a version of this page in the deletion archive?
3277          *
3278          * @return int The number of archived revisions
3279          */
3280         public function isDeleted() {
3281                 if ( $this->getNamespace() < 0 ) {
3282                         $n = 0;
3283                 } else {
3284                         $dbr = wfGetDB( DB_REPLICA );
3285
3286                         $n = $dbr->selectField( 'archive', 'COUNT(*)',
3287                                 [ 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ],
3288                                 __METHOD__
3289                         );
3290                         if ( $this->getNamespace() == NS_FILE ) {
3291                                 $n += $dbr->selectField( 'filearchive', 'COUNT(*)',
3292                                         [ 'fa_name' => $this->getDBkey() ],
3293                                         __METHOD__
3294                                 );
3295                         }
3296                 }
3297                 return (int)$n;
3298         }
3299
3300         /**
3301          * Is there a version of this page in the deletion archive?
3302          *
3303          * @return bool
3304          */
3305         public function isDeletedQuick() {
3306                 if ( $this->getNamespace() < 0 ) {
3307                         return false;
3308                 }
3309                 $dbr = wfGetDB( DB_REPLICA );
3310                 $deleted = (bool)$dbr->selectField( 'archive', '1',
3311                         [ 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ],
3312                         __METHOD__
3313                 );
3314                 if ( !$deleted && $this->getNamespace() == NS_FILE ) {
3315                         $deleted = (bool)$dbr->selectField( 'filearchive', '1',
3316                                 [ 'fa_name' => $this->getDBkey() ],
3317                                 __METHOD__
3318                         );
3319                 }
3320                 return $deleted;
3321         }
3322
3323         /**
3324          * Get the article ID for this Title from the link cache,
3325          * adding it if necessary
3326          *
3327          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select
3328          *  for update
3329          * @return int The ID
3330          */
3331         public function getArticleID( $flags = 0 ) {
3332                 if ( $this->getNamespace() < 0 ) {
3333                         $this->mArticleID = 0;
3334                         return $this->mArticleID;
3335                 }
3336                 $linkCache = LinkCache::singleton();
3337                 if ( $flags & self::GAID_FOR_UPDATE ) {
3338                         $oldUpdate = $linkCache->forUpdate( true );
3339                         $linkCache->clearLink( $this );
3340                         $this->mArticleID = $linkCache->addLinkObj( $this );
3341                         $linkCache->forUpdate( $oldUpdate );
3342                 } else {
3343                         if ( -1 == $this->mArticleID ) {
3344                                 $this->mArticleID = $linkCache->addLinkObj( $this );
3345                         }
3346                 }
3347                 return $this->mArticleID;
3348         }
3349
3350         /**
3351          * Is this an article that is a redirect page?
3352          * Uses link cache, adding it if necessary
3353          *
3354          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3355          * @return bool
3356          */
3357         public function isRedirect( $flags = 0 ) {
3358                 if ( !is_null( $this->mRedirect ) ) {
3359                         return $this->mRedirect;
3360                 }
3361                 if ( !$this->getArticleID( $flags ) ) {
3362                         $this->mRedirect = false;
3363                         return $this->mRedirect;
3364                 }
3365
3366                 $linkCache = LinkCache::singleton();
3367                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3368                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'redirect' );
3369                 if ( $cached === null ) {
3370                         # Trust LinkCache's state over our own
3371                         # LinkCache is telling us that the page doesn't exist, despite there being cached
3372                         # data relating to an existing page in $this->mArticleID. Updaters should clear
3373                         # LinkCache as appropriate, or use $flags = Title::GAID_FOR_UPDATE. If that flag is
3374                         # set, then LinkCache will definitely be up to date here, since getArticleID() forces
3375                         # LinkCache to refresh its data from the master.
3376                         $this->mRedirect = false;
3377                         return $this->mRedirect;
3378                 }
3379
3380                 $this->mRedirect = (bool)$cached;
3381
3382                 return $this->mRedirect;
3383         }
3384
3385         /**
3386          * What is the length of this page?
3387          * Uses link cache, adding it if necessary
3388          *
3389          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3390          * @return int
3391          */
3392         public function getLength( $flags = 0 ) {
3393                 if ( $this->mLength != -1 ) {
3394                         return $this->mLength;
3395                 }
3396                 if ( !$this->getArticleID( $flags ) ) {
3397                         $this->mLength = 0;
3398                         return $this->mLength;
3399                 }
3400                 $linkCache = LinkCache::singleton();
3401                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3402                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'length' );
3403                 if ( $cached === null ) {
3404                         # Trust LinkCache's state over our own, as for isRedirect()
3405                         $this->mLength = 0;
3406                         return $this->mLength;
3407                 }
3408
3409                 $this->mLength = intval( $cached );
3410
3411                 return $this->mLength;
3412         }
3413
3414         /**
3415          * What is the page_latest field for this page?
3416          *
3417          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3418          * @return int Int or 0 if the page doesn't exist
3419          */
3420         public function getLatestRevID( $flags = 0 ) {
3421                 if ( !( $flags & self::GAID_FOR_UPDATE ) && $this->mLatestID !== false ) {
3422                         return intval( $this->mLatestID );
3423                 }
3424                 if ( !$this->getArticleID( $flags ) ) {
3425                         $this->mLatestID = 0;
3426                         return $this->mLatestID;
3427                 }
3428                 $linkCache = LinkCache::singleton();
3429                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3430                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'revision' );
3431                 if ( $cached === null ) {
3432                         # Trust LinkCache's state over our own, as for isRedirect()
3433                         $this->mLatestID = 0;
3434                         return $this->mLatestID;
3435                 }
3436
3437                 $this->mLatestID = intval( $cached );
3438
3439                 return $this->mLatestID;
3440         }
3441
3442         /**
3443          * This clears some fields in this object, and clears any associated
3444          * keys in the "bad links" section of the link cache.
3445          *
3446          * - This is called from WikiPage::doEditContent() and WikiPage::insertOn() to allow
3447          * loading of the new page_id. It's also called from
3448          * WikiPage::doDeleteArticleReal()
3449          *
3450          * @param int $newid The new Article ID
3451          */
3452         public function resetArticleID( $newid ) {
3453                 $linkCache = LinkCache::singleton();
3454                 $linkCache->clearLink( $this );
3455
3456                 if ( $newid === false ) {
3457                         $this->mArticleID = -1;
3458                 } else {
3459                         $this->mArticleID = intval( $newid );
3460                 }
3461                 $this->mRestrictionsLoaded = false;
3462                 $this->mRestrictions = [];
3463                 $this->mOldRestrictions = false;
3464                 $this->mRedirect = null;
3465                 $this->mLength = -1;
3466                 $this->mLatestID = false;
3467                 $this->mContentModel = false;
3468                 $this->mEstimateRevisions = null;
3469                 $this->mPageLanguage = false;
3470                 $this->mDbPageLanguage = false;
3471                 $this->mIsBigDeletion = null;
3472         }
3473
3474         public static function clearCaches() {
3475                 $linkCache = LinkCache::singleton();
3476                 $linkCache->clear();
3477
3478                 $titleCache = self::getTitleCache();
3479                 $titleCache->clear();
3480         }
3481
3482         /**
3483          * Capitalize a text string for a title if it belongs to a namespace that capitalizes
3484          *
3485          * @param string $text Containing title to capitalize
3486          * @param int $ns Namespace index, defaults to NS_MAIN
3487          * @return string Containing capitalized title
3488          */
3489         public static function capitalize( $text, $ns = NS_MAIN ) {
3490                 global $wgContLang;
3491
3492                 if ( MWNamespace::isCapitalized( $ns ) ) {
3493                         return $wgContLang->ucfirst( $text );
3494                 } else {
3495                         return $text;
3496                 }
3497         }
3498
3499         /**
3500          * Secure and split - main initialisation function for this object
3501          *
3502          * Assumes that mDbkeyform has been set, and is urldecoded
3503          * and uses underscores, but not otherwise munged.  This function
3504          * removes illegal characters, splits off the interwiki and
3505          * namespace prefixes, sets the other forms, and canonicalizes
3506          * everything.
3507          *
3508          * @throws MalformedTitleException On invalid titles
3509          * @return bool True on success
3510          */
3511         private function secureAndSplit() {
3512                 # Initialisation
3513                 $this->mInterwiki = '';
3514                 $this->mFragment = '';
3515                 $this->mNamespace = $this->mDefaultNamespace; # Usually NS_MAIN
3516
3517                 $dbkey = $this->mDbkeyform;
3518
3519                 // @note: splitTitleString() is a temporary hack to allow MediaWikiTitleCodec to share
3520                 //        the parsing code with Title, while avoiding massive refactoring.
3521                 // @todo: get rid of secureAndSplit, refactor parsing code.
3522                 // @note: getTitleParser() returns a TitleParser implementation which does not have a
3523                 //        splitTitleString method, but the only implementation (MediaWikiTitleCodec) does
3524                 $titleCodec = MediaWikiServices::getInstance()->getTitleParser();
3525                 // MalformedTitleException can be thrown here
3526                 $parts = $titleCodec->splitTitleString( $dbkey, $this->getDefaultNamespace() );
3527
3528                 # Fill fields
3529                 $this->setFragment( '#' . $parts['fragment'] );
3530                 $this->mInterwiki = $parts['interwiki'];
3531                 $this->mLocalInterwiki = $parts['local_interwiki'];
3532                 $this->mNamespace = $parts['namespace'];
3533                 $this->mUserCaseDBKey = $parts['user_case_dbkey'];
3534
3535                 $this->mDbkeyform = $parts['dbkey'];
3536                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
3537                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
3538
3539                 # We already know that some pages won't be in the database!
3540                 if ( $this->isExternal() || $this->isSpecialPage() ) {
3541                         $this->mArticleID = 0;
3542                 }
3543
3544                 return true;
3545         }
3546
3547         /**
3548          * Get an array of Title objects linking to this Title
3549          * Also stores the IDs in the link cache.
3550          *
3551          * WARNING: do not use this function on arbitrary user-supplied titles!
3552          * On heavily-used templates it will max out the memory.
3553          *
3554          * @param array $options May be FOR UPDATE
3555          * @param string $table Table name
3556          * @param string $prefix Fields prefix
3557          * @return Title[] Array of Title objects linking here
3558          */
3559         public function getLinksTo( $options = [], $table = 'pagelinks', $prefix = 'pl' ) {
3560                 if ( count( $options ) > 0 ) {
3561                         $db = wfGetDB( DB_MASTER );
3562                 } else {
3563                         $db = wfGetDB( DB_REPLICA );
3564                 }
3565
3566                 $res = $db->select(
3567                         [ 'page', $table ],
3568                         self::getSelectFields(),
3569                         [
3570                                 "{$prefix}_from=page_id",
3571                                 "{$prefix}_namespace" => $this->getNamespace(),
3572                                 "{$prefix}_title" => $this->getDBkey() ],
3573                         __METHOD__,
3574                         $options
3575                 );
3576
3577                 $retVal = [];
3578                 if ( $res->numRows() ) {
3579                         $linkCache = LinkCache::singleton();
3580                         foreach ( $res as $row ) {
3581                                 $titleObj = self::makeTitle( $row->page_namespace, $row->page_title );
3582                                 if ( $titleObj ) {
3583                                         $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3584                                         $retVal[] = $titleObj;
3585                                 }
3586                         }
3587                 }
3588                 return $retVal;
3589         }
3590
3591         /**
3592          * Get an array of Title objects using this Title as a template
3593          * Also stores the IDs in the link cache.
3594          *
3595          * WARNING: do not use this function on arbitrary user-supplied titles!
3596          * On heavily-used templates it will max out the memory.
3597          *
3598          * @param array $options Query option to Database::select()
3599          * @return Title[] Array of Title the Title objects linking here
3600          */
3601         public function getTemplateLinksTo( $options = [] ) {
3602                 return $this->getLinksTo( $options, 'templatelinks', 'tl' );
3603         }
3604
3605         /**
3606          * Get an array of Title objects linked from this Title
3607          * Also stores the IDs in the link cache.
3608          *
3609          * WARNING: do not use this function on arbitrary user-supplied titles!
3610          * On heavily-used templates it will max out the memory.
3611          *
3612          * @param array $options Query option to Database::select()
3613          * @param string $table Table name
3614          * @param string $prefix Fields prefix
3615          * @return array Array of Title objects linking here
3616          */
3617         public function getLinksFrom( $options = [], $table = 'pagelinks', $prefix = 'pl' ) {
3618                 $id = $this->getArticleID();
3619
3620                 # If the page doesn't exist; there can't be any link from this page
3621                 if ( !$id ) {
3622                         return [];
3623                 }
3624
3625                 $db = wfGetDB( DB_REPLICA );
3626
3627                 $blNamespace = "{$prefix}_namespace";
3628                 $blTitle = "{$prefix}_title";
3629
3630                 $res = $db->select(
3631                         [ $table, 'page' ],
3632                         array_merge(
3633                                 [ $blNamespace, $blTitle ],
3634                                 WikiPage::selectFields()
3635                         ),
3636                         [ "{$prefix}_from" => $id ],
3637                         __METHOD__,
3638                         $options,
3639                         [ 'page' => [
3640                                 'LEFT JOIN',
3641                                 [ "page_namespace=$blNamespace", "page_title=$blTitle" ]
3642                         ] ]
3643                 );
3644
3645                 $retVal = [];
3646                 $linkCache = LinkCache::singleton();
3647                 foreach ( $res as $row ) {
3648                         if ( $row->page_id ) {
3649                                 $titleObj = self::newFromRow( $row );
3650                         } else {
3651                                 $titleObj = self::makeTitle( $row->$blNamespace, $row->$blTitle );
3652                                 $linkCache->addBadLinkObj( $titleObj );
3653                         }
3654                         $retVal[] = $titleObj;
3655                 }
3656
3657                 return $retVal;
3658         }
3659
3660         /**
3661          * Get an array of Title objects used on this Title as a template
3662          * Also stores the IDs in the link cache.
3663          *
3664          * WARNING: do not use this function on arbitrary user-supplied titles!
3665          * On heavily-used templates it will max out the memory.
3666          *
3667          * @param array $options May be FOR UPDATE
3668          * @return Title[] Array of Title the Title objects used here
3669          */
3670         public function getTemplateLinksFrom( $options = [] ) {
3671                 return $this->getLinksFrom( $options, 'templatelinks', 'tl' );
3672         }
3673
3674         /**
3675          * Get an array of Title objects referring to non-existent articles linked
3676          * from this page.
3677          *
3678          * @todo check if needed (used only in SpecialBrokenRedirects.php, and
3679          *   should use redirect table in this case).
3680          * @return Title[] Array of Title the Title objects
3681          */
3682         public function getBrokenLinksFrom() {
3683                 if ( $this->getArticleID() == 0 ) {
3684                         # All links from article ID 0 are false positives
3685                         return [];
3686                 }
3687
3688                 $dbr = wfGetDB( DB_REPLICA );
3689                 $res = $dbr->select(
3690                         [ 'page', 'pagelinks' ],
3691                         [ 'pl_namespace', 'pl_title' ],
3692                         [
3693                                 'pl_from' => $this->getArticleID(),
3694                                 'page_namespace IS NULL'
3695                         ],
3696                         __METHOD__, [],
3697                         [
3698                                 'page' => [
3699                                         'LEFT JOIN',
3700                                         [ 'pl_namespace=page_namespace', 'pl_title=page_title' ]
3701                                 ]
3702                         ]
3703                 );
3704
3705                 $retVal = [];
3706                 foreach ( $res as $row ) {
3707                         $retVal[] = self::makeTitle( $row->pl_namespace, $row->pl_title );
3708                 }
3709                 return $retVal;
3710         }
3711
3712         /**
3713          * Get a list of URLs to purge from the CDN cache when this
3714          * page changes
3715          *
3716          * @return string[] Array of String the URLs
3717          */
3718         public function getCdnUrls() {
3719                 $urls = [
3720                         $this->getInternalURL(),
3721                         $this->getInternalURL( 'action=history' )
3722                 ];
3723
3724                 $pageLang = $this->getPageLanguage();
3725                 if ( $pageLang->hasVariants() ) {
3726                         $variants = $pageLang->getVariants();
3727                         foreach ( $variants as $vCode ) {
3728                                 $urls[] = $this->getInternalURL( $vCode );
3729                         }
3730                 }
3731
3732                 // If we are looking at a css/js user subpage, purge the action=raw.
3733                 if ( $this->isJsSubpage() ) {
3734                         $urls[] = $this->getInternalURL( 'action=raw&ctype=text/javascript' );
3735                 } elseif ( $this->isCssSubpage() ) {
3736                         $urls[] = $this->getInternalURL( 'action=raw&ctype=text/css' );
3737                 }
3738
3739                 Hooks::run( 'TitleSquidURLs', [ $this, &$urls ] );
3740                 return $urls;
3741         }
3742
3743         /**
3744          * @deprecated since 1.27 use getCdnUrls()
3745          */
3746         public function getSquidURLs() {
3747                 return $this->getCdnUrls();
3748         }
3749
3750         /**
3751          * Purge all applicable CDN URLs
3752          */
3753         public function purgeSquid() {
3754                 DeferredUpdates::addUpdate(
3755                         new CdnCacheUpdate( $this->getCdnUrls() ),
3756                         DeferredUpdates::PRESEND
3757                 );
3758         }
3759
3760         /**
3761          * Check whether a given move operation would be valid.
3762          * Returns true if ok, or a getUserPermissionsErrors()-like array otherwise
3763          *
3764          * @deprecated since 1.25, use MovePage's methods instead
3765          * @param Title &$nt The new title
3766          * @param bool $auth Whether to check user permissions (uses $wgUser)
3767          * @param string $reason Is the log summary of the move, used for spam checking
3768          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3769          */
3770         public function isValidMoveOperation( &$nt, $auth = true, $reason = '' ) {
3771                 global $wgUser;
3772
3773                 if ( !( $nt instanceof Title ) ) {
3774                         // Normally we'd add this to $errors, but we'll get
3775                         // lots of syntax errors if $nt is not an object
3776                         return [ [ 'badtitletext' ] ];
3777                 }
3778
3779                 $mp = new MovePage( $this, $nt );
3780                 $errors = $mp->isValidMove()->getErrorsArray();
3781                 if ( $auth ) {
3782                         $errors = wfMergeErrorArrays(
3783                                 $errors,
3784                                 $mp->checkPermissions( $wgUser, $reason )->getErrorsArray()
3785                         );
3786                 }
3787
3788                 return $errors ?: true;
3789         }
3790
3791         /**
3792          * Check if the requested move target is a valid file move target
3793          * @todo move this to MovePage
3794          * @param Title $nt Target title
3795          * @return array List of errors
3796          */
3797         protected function validateFileMoveOperation( $nt ) {
3798                 global $wgUser;
3799
3800                 $errors = [];
3801
3802                 $destFile = wfLocalFile( $nt );
3803                 $destFile->load( File::READ_LATEST );
3804                 if ( !$wgUser->isAllowed( 'reupload-shared' )
3805                         && !$destFile->exists() && wfFindFile( $nt )
3806                 ) {
3807                         $errors[] = [ 'file-exists-sharedrepo' ];
3808                 }
3809
3810                 return $errors;
3811         }
3812
3813         /**
3814          * Move a title to a new location
3815          *
3816          * @deprecated since 1.25, use the MovePage class instead
3817          * @param Title &$nt The new title
3818          * @param bool $auth Indicates whether $wgUser's permissions
3819          *  should be checked
3820          * @param string $reason The reason for the move
3821          * @param bool $createRedirect Whether to create a redirect from the old title to the new title.
3822          *  Ignored if the user doesn't have the suppressredirect right.
3823          * @param array $changeTags Applied to the entry in the move log and redirect page revision
3824          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3825          */
3826         public function moveTo( &$nt, $auth = true, $reason = '', $createRedirect = true,
3827                 array $changeTags = []
3828         ) {
3829                 global $wgUser;
3830                 $err = $this->isValidMoveOperation( $nt, $auth, $reason );
3831                 if ( is_array( $err ) ) {
3832                         // Auto-block user's IP if the account was "hard" blocked
3833                         $wgUser->spreadAnyEditBlock();
3834                         return $err;
3835                 }
3836                 // Check suppressredirect permission
3837                 if ( $auth && !$wgUser->isAllowed( 'suppressredirect' ) ) {
3838                         $createRedirect = true;
3839                 }
3840
3841                 $mp = new MovePage( $this, $nt );
3842                 $status = $mp->move( $wgUser, $reason, $createRedirect, $changeTags );
3843                 if ( $status->isOK() ) {
3844                         return true;
3845                 } else {
3846                         return $status->getErrorsArray();
3847                 }
3848         }
3849
3850         /**
3851          * Move this page's subpages to be subpages of $nt
3852          *
3853          * @param Title $nt Move target
3854          * @param bool $auth Whether $wgUser's permissions should be checked
3855          * @param string $reason The reason for the move
3856          * @param bool $createRedirect Whether to create redirects from the old subpages to
3857          *     the new ones Ignored if the user doesn't have the 'suppressredirect' right
3858          * @param array $changeTags Applied to the entry in the move log and redirect page revision
3859          * @return array Array with old page titles as keys, and strings (new page titles) or
3860          *     getUserPermissionsErrors()-like arrays (errors) as values, or a
3861          *     getUserPermissionsErrors()-like error array with numeric indices if
3862          *     no pages were moved
3863          */
3864         public function moveSubpages( $nt, $auth = true, $reason = '', $createRedirect = true,
3865                 array $changeTags = []
3866         ) {
3867                 global $wgMaximumMovedPages;
3868                 // Check permissions
3869                 if ( !$this->userCan( 'move-subpages' ) ) {
3870                         return [
3871                                 [ 'cant-move-subpages' ],
3872                         ];
3873                 }
3874                 // Do the source and target namespaces support subpages?
3875                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3876                         return [
3877                                 [ 'namespace-nosubpages', MWNamespace::getCanonicalName( $this->getNamespace() ) ],
3878                         ];
3879                 }
3880                 if ( !MWNamespace::hasSubpages( $nt->getNamespace() ) ) {
3881                         return [
3882                                 [ 'namespace-nosubpages', MWNamespace::getCanonicalName( $nt->getNamespace() ) ],
3883                         ];
3884                 }
3885
3886                 $subpages = $this->getSubpages( $wgMaximumMovedPages + 1 );
3887                 $retval = [];
3888                 $count = 0;
3889                 foreach ( $subpages as $oldSubpage ) {
3890                         $count++;
3891                         if ( $count > $wgMaximumMovedPages ) {
3892                                 $retval[$oldSubpage->getPrefixedText()] = [
3893                                         [ 'movepage-max-pages', $wgMaximumMovedPages ],
3894                                 ];
3895                                 break;
3896                         }
3897
3898                         // We don't know whether this function was called before
3899                         // or after moving the root page, so check both
3900                         // $this and $nt
3901                         if ( $oldSubpage->getArticleID() == $this->getArticleID()
3902                                 || $oldSubpage->getArticleID() == $nt->getArticleID()
3903                         ) {
3904                                 // When moving a page to a subpage of itself,
3905                                 // don't move it twice
3906                                 continue;
3907                         }
3908                         $newPageName = preg_replace(
3909                                         '#^' . preg_quote( $this->getDBkey(), '#' ) . '#',
3910                                         StringUtils::escapeRegexReplacement( $nt->getDBkey() ), # T23234
3911                                         $oldSubpage->getDBkey() );
3912                         if ( $oldSubpage->isTalkPage() ) {
3913                                 $newNs = $nt->getTalkPage()->getNamespace();
3914                         } else {
3915                                 $newNs = $nt->getSubjectPage()->getNamespace();
3916                         }
3917                         # T16385: we need makeTitleSafe because the new page names may
3918                         # be longer than 255 characters.
3919                         $newSubpage = self::makeTitleSafe( $newNs, $newPageName );
3920
3921                         $success = $oldSubpage->moveTo( $newSubpage, $auth, $reason, $createRedirect, $changeTags );
3922                         if ( $success === true ) {
3923                                 $retval[$oldSubpage->getPrefixedText()] = $newSubpage->getPrefixedText();
3924                         } else {
3925                                 $retval[$oldSubpage->getPrefixedText()] = $success;
3926                         }
3927                 }
3928                 return $retval;
3929         }
3930
3931         /**
3932          * Checks if this page is just a one-rev redirect.
3933          * Adds lock, so don't use just for light purposes.
3934          *
3935          * @return bool
3936          */
3937         public function isSingleRevRedirect() {
3938                 global $wgContentHandlerUseDB;
3939
3940                 $dbw = wfGetDB( DB_MASTER );
3941
3942                 # Is it a redirect?
3943                 $fields = [ 'page_is_redirect', 'page_latest', 'page_id' ];
3944                 if ( $wgContentHandlerUseDB ) {
3945                         $fields[] = 'page_content_model';
3946                 }
3947
3948                 $row = $dbw->selectRow( 'page',
3949                         $fields,
3950                         $this->pageCond(),
3951                         __METHOD__,
3952                         [ 'FOR UPDATE' ]
3953                 );
3954                 # Cache some fields we may want
3955                 $this->mArticleID = $row ? intval( $row->page_id ) : 0;
3956                 $this->mRedirect = $row ? (bool)$row->page_is_redirect : false;
3957                 $this->mLatestID = $row ? intval( $row->page_latest ) : false;
3958                 $this->mContentModel = $row && isset( $row->page_content_model )
3959                         ? strval( $row->page_content_model )
3960                         : false;
3961
3962                 if ( !$this->mRedirect ) {
3963                         return false;
3964                 }
3965                 # Does the article have a history?
3966                 $row = $dbw->selectField( [ 'page', 'revision' ],
3967                         'rev_id',
3968                         [ 'page_namespace' => $this->getNamespace(),
3969                                 'page_title' => $this->getDBkey(),
3970                                 'page_id=rev_page',
3971                                 'page_latest != rev_id'
3972                         ],
3973                         __METHOD__,
3974                         [ 'FOR UPDATE' ]
3975                 );
3976                 # Return true if there was no history
3977                 return ( $row === false );
3978         }
3979
3980         /**
3981          * Checks if $this can be moved to a given Title
3982          * - Selects for update, so don't call it unless you mean business
3983          *
3984          * @deprecated since 1.25, use MovePage's methods instead
3985          * @param Title $nt The new title to check
3986          * @return bool
3987          */
3988         public function isValidMoveTarget( $nt ) {
3989                 # Is it an existing file?
3990                 if ( $nt->getNamespace() == NS_FILE ) {
3991                         $file = wfLocalFile( $nt );
3992                         $file->load( File::READ_LATEST );
3993                         if ( $file->exists() ) {
3994                                 wfDebug( __METHOD__ . ": file exists\n" );
3995                                 return false;
3996                         }
3997                 }
3998                 # Is it a redirect with no history?
3999                 if ( !$nt->isSingleRevRedirect() ) {
4000                         wfDebug( __METHOD__ . ": not a one-rev redirect\n" );
4001                         return false;
4002                 }
4003                 # Get the article text
4004                 $rev = Revision::newFromTitle( $nt, false, Revision::READ_LATEST );
4005                 if ( !is_object( $rev ) ) {
4006                         return false;
4007                 }
4008                 $content = $rev->getContent();
4009                 # Does the redirect point to the source?
4010                 # Or is it a broken self-redirect, usually caused by namespace collisions?
4011                 $redirTitle = $content ? $content->getRedirectTarget() : null;
4012
4013                 if ( $redirTitle ) {
4014                         if ( $redirTitle->getPrefixedDBkey() != $this->getPrefixedDBkey() &&
4015                                 $redirTitle->getPrefixedDBkey() != $nt->getPrefixedDBkey() ) {
4016                                 wfDebug( __METHOD__ . ": redirect points to other page\n" );
4017                                 return false;
4018                         } else {
4019                                 return true;
4020                         }
4021                 } else {
4022                         # Fail safe (not a redirect after all. strange.)
4023                         wfDebug( __METHOD__ . ": failsafe: database sais " . $nt->getPrefixedDBkey() .
4024                                                 " is a redirect, but it doesn't contain a valid redirect.\n" );
4025                         return false;
4026                 }
4027         }
4028
4029         /**
4030          * Get categories to which this Title belongs and return an array of
4031          * categories' names.
4032          *
4033          * @return array Array of parents in the form:
4034          *     $parent => $currentarticle
4035          */
4036         public function getParentCategories() {
4037                 global $wgContLang;
4038
4039                 $data = [];
4040
4041                 $titleKey = $this->getArticleID();
4042
4043                 if ( $titleKey === 0 ) {
4044                         return $data;
4045                 }
4046
4047                 $dbr = wfGetDB( DB_REPLICA );
4048
4049                 $res = $dbr->select(
4050                         'categorylinks',
4051                         'cl_to',
4052                         [ 'cl_from' => $titleKey ],
4053                         __METHOD__
4054                 );
4055
4056                 if ( $res->numRows() > 0 ) {
4057                         foreach ( $res as $row ) {
4058                                 // $data[] = Title::newFromText($wgContLang->getNsText ( NS_CATEGORY ).':'.$row->cl_to);
4059                                 $data[$wgContLang->getNsText( NS_CATEGORY ) . ':' . $row->cl_to] = $this->getFullText();
4060                         }
4061                 }
4062                 return $data;
4063         }
4064
4065         /**
4066          * Get a tree of parent categories
4067          *
4068          * @param array $children Array with the children in the keys, to check for circular refs
4069          * @return array Tree of parent categories
4070          */
4071         public function getParentCategoryTree( $children = [] ) {
4072                 $stack = [];
4073                 $parents = $this->getParentCategories();
4074
4075                 if ( $parents ) {
4076                         foreach ( $parents as $parent => $current ) {
4077                                 if ( array_key_exists( $parent, $children ) ) {
4078                                         # Circular reference
4079                                         $stack[$parent] = [];
4080                                 } else {
4081                                         $nt = self::newFromText( $parent );
4082                                         if ( $nt ) {
4083                                                 $stack[$parent] = $nt->getParentCategoryTree( $children + [ $parent => 1 ] );
4084                                         }
4085                                 }
4086                         }
4087                 }
4088
4089                 return $stack;
4090         }
4091
4092         /**
4093          * Get an associative array for selecting this title from
4094          * the "page" table
4095          *
4096          * @return array Array suitable for the $where parameter of DB::select()
4097          */
4098         public function pageCond() {
4099                 if ( $this->mArticleID > 0 ) {
4100                         // PK avoids secondary lookups in InnoDB, shouldn't hurt other DBs
4101                         return [ 'page_id' => $this->mArticleID ];
4102                 } else {
4103                         return [ 'page_namespace' => $this->mNamespace, 'page_title' => $this->mDbkeyform ];
4104                 }
4105         }
4106
4107         /**
4108          * Get next/previous revision ID relative to another revision ID
4109          * @param int $revId Revision ID. Get the revision that was before this one.
4110          * @param int $flags Title::GAID_FOR_UPDATE
4111          * @param string $dir 'next' or 'prev'
4112          * @return int|bool New revision ID, or false if none exists
4113          */
4114         private function getRelativeRevisionID( $revId, $flags, $dir ) {
4115                 $revId = (int)$revId;
4116                 if ( $dir === 'next' ) {
4117                         $op = '>';
4118                         $sort = 'ASC';
4119                 } elseif ( $dir === 'prev' ) {
4120                         $op = '<';
4121                         $sort = 'DESC';
4122                 } else {
4123                         throw new InvalidArgumentException( '$dir must be "next" or "prev"' );
4124                 }
4125
4126                 if ( $flags & self::GAID_FOR_UPDATE ) {
4127                         $db = wfGetDB( DB_MASTER );
4128                 } else {
4129                         $db = wfGetDB( DB_REPLICA, 'contributions' );
4130                 }
4131
4132                 // Intentionally not caring if the specified revision belongs to this
4133                 // page. We only care about the timestamp.
4134                 $ts = $db->selectField( 'revision', 'rev_timestamp', [ 'rev_id' => $revId ], __METHOD__ );
4135                 if ( $ts === false ) {
4136                         $ts = $db->selectField( 'archive', 'ar_timestamp', [ 'ar_rev_id' => $revId ], __METHOD__ );
4137                         if ( $ts === false ) {
4138                                 // Or should this throw an InvalidArgumentException or something?
4139                                 return false;
4140                         }
4141                 }
4142                 $ts = $db->addQuotes( $ts );
4143
4144                 $revId = $db->selectField( 'revision', 'rev_id',
4145                         [
4146                                 'rev_page' => $this->getArticleID( $flags ),
4147                                 "rev_timestamp $op $ts OR (rev_timestamp = $ts AND rev_id $op $revId)"
4148                         ],
4149                         __METHOD__,
4150                         [
4151                                 'ORDER BY' => "rev_timestamp $sort, rev_id $sort",
4152                                 'IGNORE INDEX' => 'rev_timestamp', // Probably needed for T159319
4153                         ]
4154                 );
4155
4156                 if ( $revId === false ) {
4157                         return false;
4158                 } else {
4159                         return intval( $revId );
4160                 }
4161         }
4162
4163         /**
4164          * Get the revision ID of the previous revision
4165          *
4166          * @param int $revId Revision ID. Get the revision that was before this one.
4167          * @param int $flags Title::GAID_FOR_UPDATE
4168          * @return int|bool Old revision ID, or false if none exists
4169          */
4170         public function getPreviousRevisionID( $revId, $flags = 0 ) {
4171                 return $this->getRelativeRevisionID( $revId, $flags, 'prev' );
4172         }
4173
4174         /**
4175          * Get the revision ID of the next revision
4176          *
4177          * @param int $revId Revision ID. Get the revision that was after this one.
4178          * @param int $flags Title::GAID_FOR_UPDATE
4179          * @return int|bool Next revision ID, or false if none exists
4180          */
4181         public function getNextRevisionID( $revId, $flags = 0 ) {
4182                 return $this->getRelativeRevisionID( $revId, $flags, 'next' );
4183         }
4184
4185         /**
4186          * Get the first revision of the page
4187          *
4188          * @param int $flags Title::GAID_FOR_UPDATE
4189          * @return Revision|null If page doesn't exist
4190          */
4191         public function getFirstRevision( $flags = 0 ) {
4192                 $pageId = $this->getArticleID( $flags );
4193                 if ( $pageId ) {
4194                         $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_REPLICA );
4195                         $row = $db->selectRow( 'revision', Revision::selectFields(),
4196                                 [ 'rev_page' => $pageId ],
4197                                 __METHOD__,
4198                                 [
4199                                         'ORDER BY' => 'rev_timestamp ASC, rev_id ASC',
4200                                         'IGNORE INDEX' => 'rev_timestamp', // See T159319
4201                                 ]
4202                         );
4203                         if ( $row ) {
4204                                 return new Revision( $row );
4205                         }
4206                 }
4207                 return null;
4208         }
4209
4210         /**
4211          * Get the oldest revision timestamp of this page
4212          *
4213          * @param int $flags Title::GAID_FOR_UPDATE
4214          * @return string MW timestamp
4215          */
4216         public function getEarliestRevTime( $flags = 0 ) {
4217                 $rev = $this->getFirstRevision( $flags );
4218                 return $rev ? $rev->getTimestamp() : null;
4219         }
4220
4221         /**
4222          * Check if this is a new page
4223          *
4224          * @return bool
4225          */
4226         public function isNewPage() {
4227                 $dbr = wfGetDB( DB_REPLICA );
4228                 return (bool)$dbr->selectField( 'page', 'page_is_new', $this->pageCond(), __METHOD__ );
4229         }
4230
4231         /**
4232          * Check whether the number of revisions of this page surpasses $wgDeleteRevisionsLimit
4233          *
4234          * @return bool
4235          */
4236         public function isBigDeletion() {
4237                 global $wgDeleteRevisionsLimit;
4238
4239                 if ( !$wgDeleteRevisionsLimit ) {
4240                         return false;
4241                 }
4242
4243                 if ( $this->mIsBigDeletion === null ) {
4244                         $dbr = wfGetDB( DB_REPLICA );
4245
4246                         $revCount = $dbr->selectRowCount(
4247                                 'revision',
4248                                 '1',
4249                                 [ 'rev_page' => $this->getArticleID() ],
4250                                 __METHOD__,
4251                                 [ 'LIMIT' => $wgDeleteRevisionsLimit + 1 ]
4252                         );
4253
4254                         $this->mIsBigDeletion = $revCount > $wgDeleteRevisionsLimit;
4255                 }
4256
4257                 return $this->mIsBigDeletion;
4258         }
4259
4260         /**
4261          * Get the approximate revision count of this page.
4262          *
4263          * @return int
4264          */
4265         public function estimateRevisionCount() {
4266                 if ( !$this->exists() ) {
4267                         return 0;
4268                 }
4269
4270                 if ( $this->mEstimateRevisions === null ) {
4271                         $dbr = wfGetDB( DB_REPLICA );
4272                         $this->mEstimateRevisions = $dbr->estimateRowCount( 'revision', '*',
4273                                 [ 'rev_page' => $this->getArticleID() ], __METHOD__ );
4274                 }
4275
4276                 return $this->mEstimateRevisions;
4277         }
4278
4279         /**
4280          * Get the number of revisions between the given revision.
4281          * Used for diffs and other things that really need it.
4282          *
4283          * @param int|Revision $old Old revision or rev ID (first before range)
4284          * @param int|Revision $new New revision or rev ID (first after range)
4285          * @param int|null $max Limit of Revisions to count, will be incremented to detect truncations
4286          * @return int Number of revisions between these revisions.
4287          */
4288         public function countRevisionsBetween( $old, $new, $max = null ) {
4289                 if ( !( $old instanceof Revision ) ) {
4290                         $old = Revision::newFromTitle( $this, (int)$old );
4291                 }
4292                 if ( !( $new instanceof Revision ) ) {
4293                         $new = Revision::newFromTitle( $this, (int)$new );
4294                 }
4295                 if ( !$old || !$new ) {
4296                         return 0; // nothing to compare
4297                 }
4298                 $dbr = wfGetDB( DB_REPLICA );
4299                 $conds = [
4300                         'rev_page' => $this->getArticleID(),
4301                         'rev_timestamp > ' . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4302                         'rev_timestamp < ' . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4303                 ];
4304                 if ( $max !== null ) {
4305                         return $dbr->selectRowCount( 'revision', '1',
4306                                 $conds,
4307                                 __METHOD__,
4308                                 [ 'LIMIT' => $max + 1 ] // extra to detect truncation
4309                         );
4310                 } else {
4311                         return (int)$dbr->selectField( 'revision', 'count(*)', $conds, __METHOD__ );
4312                 }
4313         }
4314
4315         /**
4316          * Get the authors between the given revisions or revision IDs.
4317          * Used for diffs and other things that really need it.
4318          *
4319          * @since 1.23
4320          *
4321          * @param int|Revision $old Old revision or rev ID (first before range by default)
4322          * @param int|Revision $new New revision or rev ID (first after range by default)
4323          * @param int $limit Maximum number of authors
4324          * @param string|array $options (Optional): Single option, or an array of options:
4325          *     'include_old' Include $old in the range; $new is excluded.
4326          *     'include_new' Include $new in the range; $old is excluded.
4327          *     'include_both' Include both $old and $new in the range.
4328          *     Unknown option values are ignored.
4329          * @return array|null Names of revision authors in the range; null if not both revisions exist
4330          */
4331         public function getAuthorsBetween( $old, $new, $limit, $options = [] ) {
4332                 if ( !( $old instanceof Revision ) ) {
4333                         $old = Revision::newFromTitle( $this, (int)$old );
4334                 }
4335                 if ( !( $new instanceof Revision ) ) {
4336                         $new = Revision::newFromTitle( $this, (int)$new );
4337                 }
4338                 // XXX: what if Revision objects are passed in, but they don't refer to this title?
4339                 // Add $old->getPage() != $new->getPage() || $old->getPage() != $this->getArticleID()
4340                 // in the sanity check below?
4341                 if ( !$old || !$new ) {
4342                         return null; // nothing to compare
4343                 }
4344                 $authors = [];
4345                 $old_cmp = '>';
4346                 $new_cmp = '<';
4347                 $options = (array)$options;
4348                 if ( in_array( 'include_old', $options ) ) {
4349                         $old_cmp = '>=';
4350                 }
4351                 if ( in_array( 'include_new', $options ) ) {
4352                         $new_cmp = '<=';
4353                 }
4354                 if ( in_array( 'include_both', $options ) ) {
4355                         $old_cmp = '>=';
4356                         $new_cmp = '<=';
4357                 }
4358                 // No DB query needed if $old and $new are the same or successive revisions:
4359                 if ( $old->getId() === $new->getId() ) {
4360                         return ( $old_cmp === '>' && $new_cmp === '<' ) ?
4361                                 [] :
4362                                 [ $old->getUserText( Revision::RAW ) ];
4363                 } elseif ( $old->getId() === $new->getParentId() ) {
4364                         if ( $old_cmp === '>=' && $new_cmp === '<=' ) {
4365                                 $authors[] = $old->getUserText( Revision::RAW );
4366                                 if ( $old->getUserText( Revision::RAW ) != $new->getUserText( Revision::RAW ) ) {
4367                                         $authors[] = $new->getUserText( Revision::RAW );
4368                                 }
4369                         } elseif ( $old_cmp === '>=' ) {
4370                                 $authors[] = $old->getUserText( Revision::RAW );
4371                         } elseif ( $new_cmp === '<=' ) {
4372                                 $authors[] = $new->getUserText( Revision::RAW );
4373                         }
4374                         return $authors;
4375                 }
4376                 $dbr = wfGetDB( DB_REPLICA );
4377                 $res = $dbr->select( 'revision', 'DISTINCT rev_user_text',
4378                         [
4379                                 'rev_page' => $this->getArticleID(),
4380                                 "rev_timestamp $old_cmp " . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4381                                 "rev_timestamp $new_cmp " . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4382                         ], __METHOD__,
4383                         [ 'LIMIT' => $limit + 1 ] // add one so caller knows it was truncated
4384                 );
4385                 foreach ( $res as $row ) {
4386                         $authors[] = $row->rev_user_text;
4387                 }
4388                 return $authors;
4389         }
4390
4391         /**
4392          * Get the number of authors between the given revisions or revision IDs.
4393          * Used for diffs and other things that really need it.
4394          *
4395          * @param int|Revision $old Old revision or rev ID (first before range by default)
4396          * @param int|Revision $new New revision or rev ID (first after range by default)
4397          * @param int $limit Maximum number of authors
4398          * @param string|array $options (Optional): Single option, or an array of options:
4399          *     'include_old' Include $old in the range; $new is excluded.
4400          *     'include_new' Include $new in the range; $old is excluded.
4401          *     'include_both' Include both $old and $new in the range.
4402          *     Unknown option values are ignored.
4403          * @return int Number of revision authors in the range; zero if not both revisions exist
4404          */
4405         public function countAuthorsBetween( $old, $new, $limit, $options = [] ) {
4406                 $authors = $this->getAuthorsBetween( $old, $new, $limit, $options );
4407                 return $authors ? count( $authors ) : 0;
4408         }
4409
4410         /**
4411          * Compare with another title.
4412          *
4413          * @param Title $title
4414          * @return bool
4415          */
4416         public function equals( Title $title ) {
4417                 // Note: === is necessary for proper matching of number-like titles.
4418                 return $this->getInterwiki() === $title->getInterwiki()
4419                         && $this->getNamespace() == $title->getNamespace()
4420                         && $this->getDBkey() === $title->getDBkey();
4421         }
4422
4423         /**
4424          * Check if this title is a subpage of another title
4425          *
4426          * @param Title $title
4427          * @return bool
4428          */
4429         public function isSubpageOf( Title $title ) {
4430                 return $this->getInterwiki() === $title->getInterwiki()
4431                         && $this->getNamespace() == $title->getNamespace()
4432                         && strpos( $this->getDBkey(), $title->getDBkey() . '/' ) === 0;
4433         }
4434
4435         /**
4436          * Check if page exists.  For historical reasons, this function simply
4437          * checks for the existence of the title in the page table, and will
4438          * thus return false for interwiki links, special pages and the like.
4439          * If you want to know if a title can be meaningfully viewed, you should
4440          * probably call the isKnown() method instead.
4441          *
4442          * @param int $flags An optional bit field; may be Title::GAID_FOR_UPDATE to check
4443          *   from master/for update
4444          * @return bool
4445          */
4446         public function exists( $flags = 0 ) {
4447                 $exists = $this->getArticleID( $flags ) != 0;
4448                 Hooks::run( 'TitleExists', [ $this, &$exists ] );
4449                 return $exists;
4450         }
4451
4452         /**
4453          * Should links to this title be shown as potentially viewable (i.e. as
4454          * "bluelinks"), even if there's no record by this title in the page
4455          * table?
4456          *
4457          * This function is semi-deprecated for public use, as well as somewhat
4458          * misleadingly named.  You probably just want to call isKnown(), which
4459          * calls this function internally.
4460          *
4461          * (ISSUE: Most of these checks are cheap, but the file existence check
4462          * can potentially be quite expensive.  Including it here fixes a lot of
4463          * existing code, but we might want to add an optional parameter to skip
4464          * it and any other expensive checks.)
4465          *
4466          * @return bool
4467          */
4468         public function isAlwaysKnown() {
4469                 $isKnown = null;
4470
4471                 /**
4472                  * Allows overriding default behavior for determining if a page exists.
4473                  * If $isKnown is kept as null, regular checks happen. If it's
4474                  * a boolean, this value is returned by the isKnown method.
4475                  *
4476                  * @since 1.20
4477                  *
4478                  * @param Title $title
4479                  * @param bool|null $isKnown
4480                  */
4481                 Hooks::run( 'TitleIsAlwaysKnown', [ $this, &$isKnown ] );
4482
4483                 if ( !is_null( $isKnown ) ) {
4484                         return $isKnown;
4485                 }
4486
4487                 if ( $this->isExternal() ) {
4488                         return true;  // any interwiki link might be viewable, for all we know
4489                 }
4490
4491                 switch ( $this->mNamespace ) {
4492                         case NS_MEDIA:
4493                         case NS_FILE:
4494                                 // file exists, possibly in a foreign repo
4495                                 return (bool)wfFindFile( $this );
4496                         case NS_SPECIAL:
4497                                 // valid special page
4498                                 return SpecialPageFactory::exists( $this->getDBkey() );
4499                         case NS_MAIN:
4500                                 // selflink, possibly with fragment
4501                                 return $this->mDbkeyform == '';
4502                         case NS_MEDIAWIKI:
4503                                 // known system message
4504                                 return $this->hasSourceText() !== false;
4505                         default:
4506                                 return false;
4507                 }
4508         }
4509
4510         /**
4511          * Does this title refer to a page that can (or might) be meaningfully
4512          * viewed?  In particular, this function may be used to determine if
4513          * links to the title should be rendered as "bluelinks" (as opposed to
4514          * "redlinks" to non-existent pages).
4515          * Adding something else to this function will cause inconsistency
4516          * since LinkHolderArray calls isAlwaysKnown() and does its own
4517          * page existence check.
4518          *
4519          * @return bool
4520          */
4521         public function isKnown() {
4522                 return $this->isAlwaysKnown() || $this->exists();
4523         }
4524
4525         /**
4526          * Does this page have source text?
4527          *
4528          * @return bool
4529          */
4530         public function hasSourceText() {
4531                 if ( $this->exists() ) {
4532                         return true;
4533                 }
4534
4535                 if ( $this->mNamespace == NS_MEDIAWIKI ) {
4536                         // If the page doesn't exist but is a known system message, default
4537                         // message content will be displayed, same for language subpages-
4538                         // Use always content language to avoid loading hundreds of languages
4539                         // to get the link color.
4540                         global $wgContLang;
4541                         list( $name, ) = MessageCache::singleton()->figureMessage(
4542                                 $wgContLang->lcfirst( $this->getText() )
4543                         );
4544                         $message = wfMessage( $name )->inLanguage( $wgContLang )->useDatabase( false );
4545                         return $message->exists();
4546                 }
4547
4548                 return false;
4549         }
4550
4551         /**
4552          * Get the default message text or false if the message doesn't exist
4553          *
4554          * @return string|bool
4555          */
4556         public function getDefaultMessageText() {
4557                 global $wgContLang;
4558
4559                 if ( $this->getNamespace() != NS_MEDIAWIKI ) { // Just in case
4560                         return false;
4561                 }
4562
4563                 list( $name, $lang ) = MessageCache::singleton()->figureMessage(
4564                         $wgContLang->lcfirst( $this->getText() )
4565                 );
4566                 $message = wfMessage( $name )->inLanguage( $lang )->useDatabase( false );
4567
4568                 if ( $message->exists() ) {
4569                         return $message->plain();
4570                 } else {
4571                         return false;
4572                 }
4573         }
4574
4575         /**
4576          * Updates page_touched for this page; called from LinksUpdate.php
4577          *
4578          * @param string $purgeTime [optional] TS_MW timestamp
4579          * @return bool True if the update succeeded
4580          */
4581         public function invalidateCache( $purgeTime = null ) {
4582                 if ( wfReadOnly() ) {
4583                         return false;
4584                 } elseif ( $this->mArticleID === 0 ) {
4585                         return true; // avoid gap locking if we know it's not there
4586                 }
4587
4588                 $dbw = wfGetDB( DB_MASTER );
4589                 $dbw->onTransactionPreCommitOrIdle( function () {
4590                         ResourceLoaderWikiModule::invalidateModuleCache( $this, null, null, wfWikiID() );
4591                 } );
4592
4593                 $conds = $this->pageCond();
4594                 DeferredUpdates::addUpdate(
4595                         new AutoCommitUpdate(
4596                                 $dbw,
4597                                 __METHOD__,
4598                                 function ( IDatabase $dbw, $fname ) use ( $conds, $purgeTime ) {
4599                                         $dbTimestamp = $dbw->timestamp( $purgeTime ?: time() );
4600                                         $dbw->update(
4601                                                 'page',
4602                                                 [ 'page_touched' => $dbTimestamp ],
4603                                                 $conds + [ 'page_touched < ' . $dbw->addQuotes( $dbTimestamp ) ],
4604                                                 $fname
4605                                         );
4606                                         MediaWikiServices::getInstance()->getLinkCache()->invalidateTitle( $this );
4607                                 }
4608                         ),
4609                         DeferredUpdates::PRESEND
4610                 );
4611
4612                 return true;
4613         }
4614
4615         /**
4616          * Update page_touched timestamps and send CDN purge messages for
4617          * pages linking to this title. May be sent to the job queue depending
4618          * on the number of links. Typically called on create and delete.
4619          */
4620         public function touchLinks() {
4621                 DeferredUpdates::addUpdate( new HTMLCacheUpdate( $this, 'pagelinks' ) );
4622                 if ( $this->getNamespace() == NS_CATEGORY ) {
4623                         DeferredUpdates::addUpdate( new HTMLCacheUpdate( $this, 'categorylinks' ) );
4624                 }
4625         }
4626
4627         /**
4628          * Get the last touched timestamp
4629          *
4630          * @param IDatabase $db Optional db
4631          * @return string|false Last-touched timestamp
4632          */
4633         public function getTouched( $db = null ) {
4634                 if ( $db === null ) {
4635                         $db = wfGetDB( DB_REPLICA );
4636                 }
4637                 $touched = $db->selectField( 'page', 'page_touched', $this->pageCond(), __METHOD__ );
4638                 return $touched;
4639         }
4640
4641         /**
4642          * Get the timestamp when this page was updated since the user last saw it.
4643          *
4644          * @param User $user
4645          * @return string|null
4646          */
4647         public function getNotificationTimestamp( $user = null ) {
4648                 global $wgUser;
4649
4650                 // Assume current user if none given
4651                 if ( !$user ) {
4652                         $user = $wgUser;
4653                 }
4654                 // Check cache first
4655                 $uid = $user->getId();
4656                 if ( !$uid ) {
4657                         return false;
4658                 }
4659                 // avoid isset here, as it'll return false for null entries
4660                 if ( array_key_exists( $uid, $this->mNotificationTimestamp ) ) {
4661                         return $this->mNotificationTimestamp[$uid];
4662                 }
4663                 // Don't cache too much!
4664                 if ( count( $this->mNotificationTimestamp ) >= self::CACHE_MAX ) {
4665                         $this->mNotificationTimestamp = [];
4666                 }
4667
4668                 $store = MediaWikiServices::getInstance()->getWatchedItemStore();
4669                 $watchedItem = $store->getWatchedItem( $user, $this );
4670                 if ( $watchedItem ) {
4671                         $this->mNotificationTimestamp[$uid] = $watchedItem->getNotificationTimestamp();
4672                 } else {
4673                         $this->mNotificationTimestamp[$uid] = false;
4674                 }
4675
4676                 return $this->mNotificationTimestamp[$uid];
4677         }
4678
4679         /**
4680          * Generate strings used for xml 'id' names in monobook tabs
4681          *
4682          * @param string $prepend Defaults to 'nstab-'
4683          * @return string XML 'id' name
4684          */
4685         public function getNamespaceKey( $prepend = 'nstab-' ) {
4686                 global $wgContLang;
4687                 // Gets the subject namespace if this title
4688                 $namespace = MWNamespace::getSubject( $this->getNamespace() );
4689                 // Checks if canonical namespace name exists for namespace
4690                 if ( MWNamespace::exists( $this->getNamespace() ) ) {
4691                         // Uses canonical namespace name
4692                         $namespaceKey = MWNamespace::getCanonicalName( $namespace );
4693                 } else {
4694                         // Uses text of namespace
4695                         $namespaceKey = $this->getSubjectNsText();
4696                 }
4697                 // Makes namespace key lowercase
4698                 $namespaceKey = $wgContLang->lc( $namespaceKey );
4699                 // Uses main
4700                 if ( $namespaceKey == '' ) {
4701                         $namespaceKey = 'main';
4702                 }
4703                 // Changes file to image for backwards compatibility
4704                 if ( $namespaceKey == 'file' ) {
4705                         $namespaceKey = 'image';
4706                 }
4707                 return $prepend . $namespaceKey;
4708         }
4709
4710         /**
4711          * Get all extant redirects to this Title
4712          *
4713          * @param int|null $ns Single namespace to consider; null to consider all namespaces
4714          * @return Title[] Array of Title redirects to this title
4715          */
4716         public function getRedirectsHere( $ns = null ) {
4717                 $redirs = [];
4718
4719                 $dbr = wfGetDB( DB_REPLICA );
4720                 $where = [
4721                         'rd_namespace' => $this->getNamespace(),
4722                         'rd_title' => $this->getDBkey(),
4723                         'rd_from = page_id'
4724                 ];
4725                 if ( $this->isExternal() ) {
4726                         $where['rd_interwiki'] = $this->getInterwiki();
4727                 } else {
4728                         $where[] = 'rd_interwiki = ' . $dbr->addQuotes( '' ) . ' OR rd_interwiki IS NULL';
4729                 }
4730                 if ( !is_null( $ns ) ) {
4731                         $where['page_namespace'] = $ns;
4732                 }
4733
4734                 $res = $dbr->select(
4735                         [ 'redirect', 'page' ],
4736                         [ 'page_namespace', 'page_title' ],
4737                         $where,
4738                         __METHOD__
4739                 );
4740
4741                 foreach ( $res as $row ) {
4742                         $redirs[] = self::newFromRow( $row );
4743                 }
4744                 return $redirs;
4745         }
4746
4747         /**
4748          * Check if this Title is a valid redirect target
4749          *
4750          * @return bool
4751          */
4752         public function isValidRedirectTarget() {
4753                 global $wgInvalidRedirectTargets;
4754
4755                 if ( $this->isSpecialPage() ) {
4756                         // invalid redirect targets are stored in a global array, but explicitly disallow Userlogout here
4757                         if ( $this->isSpecial( 'Userlogout' ) ) {
4758                                 return false;
4759                         }
4760
4761                         foreach ( $wgInvalidRedirectTargets as $target ) {
4762                                 if ( $this->isSpecial( $target ) ) {
4763                                         return false;
4764                                 }
4765                         }
4766                 }
4767
4768                 return true;
4769         }
4770
4771         /**
4772          * Get a backlink cache object
4773          *
4774          * @return BacklinkCache
4775          */
4776         public function getBacklinkCache() {
4777                 return BacklinkCache::get( $this );
4778         }
4779
4780         /**
4781          * Whether the magic words __INDEX__ and __NOINDEX__ function for this page.
4782          *
4783          * @return bool
4784          */
4785         public function canUseNoindex() {
4786                 global $wgExemptFromUserRobotsControl;
4787
4788                 $bannedNamespaces = is_null( $wgExemptFromUserRobotsControl )
4789                         ? MWNamespace::getContentNamespaces()
4790                         : $wgExemptFromUserRobotsControl;
4791
4792                 return !in_array( $this->mNamespace, $bannedNamespaces );
4793         }
4794
4795         /**
4796          * Returns the raw sort key to be used for categories, with the specified
4797          * prefix.  This will be fed to Collation::getSortKey() to get a
4798          * binary sortkey that can be used for actual sorting.
4799          *
4800          * @param string $prefix The prefix to be used, specified using
4801          *   {{defaultsort:}} or like [[Category:Foo|prefix]].  Empty for no
4802          *   prefix.
4803          * @return string
4804          */
4805         public function getCategorySortkey( $prefix = '' ) {
4806                 $unprefixed = $this->getText();
4807
4808                 // Anything that uses this hook should only depend
4809                 // on the Title object passed in, and should probably
4810                 // tell the users to run updateCollations.php --force
4811                 // in order to re-sort existing category relations.
4812                 Hooks::run( 'GetDefaultSortkey', [ $this, &$unprefixed ] );
4813                 if ( $prefix !== '' ) {
4814                         # Separate with a line feed, so the unprefixed part is only used as
4815                         # a tiebreaker when two pages have the exact same prefix.
4816                         # In UCA, tab is the only character that can sort above LF
4817                         # so we strip both of them from the original prefix.
4818                         $prefix = strtr( $prefix, "\n\t", '  ' );
4819                         return "$prefix\n$unprefixed";
4820                 }
4821                 return $unprefixed;
4822         }
4823
4824         /**
4825          * Returns the page language code saved in the database, if $wgPageLanguageUseDB is set
4826          * to true in LocalSettings.php, otherwise returns false. If there is no language saved in
4827          * the db, it will return NULL.
4828          *
4829          * @return string|null|bool
4830          */
4831         private function getDbPageLanguageCode() {
4832                 global $wgPageLanguageUseDB;
4833
4834                 // check, if the page language could be saved in the database, and if so and
4835                 // the value is not requested already, lookup the page language using LinkCache
4836                 if ( $wgPageLanguageUseDB && $this->mDbPageLanguage === false ) {
4837                         $linkCache = LinkCache::singleton();
4838                         $linkCache->addLinkObj( $this );
4839                         $this->mDbPageLanguage = $linkCache->getGoodLinkFieldObj( $this, 'lang' );
4840                 }
4841
4842                 return $this->mDbPageLanguage;
4843         }
4844
4845         /**
4846          * Get the language in which the content of this page is written in
4847          * wikitext. Defaults to $wgContLang, but in certain cases it can be
4848          * e.g. $wgLang (such as special pages, which are in the user language).
4849          *
4850          * @since 1.18
4851          * @return Language
4852          */
4853         public function getPageLanguage() {
4854                 global $wgLang, $wgLanguageCode;
4855                 if ( $this->isSpecialPage() ) {
4856                         // special pages are in the user language
4857                         return $wgLang;
4858                 }
4859
4860                 // Checking if DB language is set
4861                 $dbPageLanguage = $this->getDbPageLanguageCode();
4862                 if ( $dbPageLanguage ) {
4863                         return wfGetLangObj( $dbPageLanguage );
4864                 }
4865
4866                 if ( !$this->mPageLanguage || $this->mPageLanguage[1] !== $wgLanguageCode ) {
4867                         // Note that this may depend on user settings, so the cache should
4868                         // be only per-request.
4869                         // NOTE: ContentHandler::getPageLanguage() may need to load the
4870                         // content to determine the page language!
4871                         // Checking $wgLanguageCode hasn't changed for the benefit of unit
4872                         // tests.
4873                         $contentHandler = ContentHandler::getForTitle( $this );
4874                         $langObj = $contentHandler->getPageLanguage( $this );
4875                         $this->mPageLanguage = [ $langObj->getCode(), $wgLanguageCode ];
4876                 } else {
4877                         $langObj = wfGetLangObj( $this->mPageLanguage[0] );
4878                 }
4879
4880                 return $langObj;
4881         }
4882
4883         /**
4884          * Get the language in which the content of this page is written when
4885          * viewed by user. Defaults to $wgContLang, but in certain cases it can be
4886          * e.g. $wgLang (such as special pages, which are in the user language).
4887          *
4888          * @since 1.20
4889          * @return Language
4890          */
4891         public function getPageViewLanguage() {
4892                 global $wgLang;
4893
4894                 if ( $this->isSpecialPage() ) {
4895                         // If the user chooses a variant, the content is actually
4896                         // in a language whose code is the variant code.
4897                         $variant = $wgLang->getPreferredVariant();
4898                         if ( $wgLang->getCode() !== $variant ) {
4899                                 return Language::factory( $variant );
4900                         }
4901
4902                         return $wgLang;
4903                 }
4904
4905                 // Checking if DB language is set
4906                 $dbPageLanguage = $this->getDbPageLanguageCode();
4907                 if ( $dbPageLanguage ) {
4908                         $pageLang = wfGetLangObj( $dbPageLanguage );
4909                         $variant = $pageLang->getPreferredVariant();
4910                         if ( $pageLang->getCode() !== $variant ) {
4911                                 $pageLang = Language::factory( $variant );
4912                         }
4913
4914                         return $pageLang;
4915                 }
4916
4917                 // @note Can't be cached persistently, depends on user settings.
4918                 // @note ContentHandler::getPageViewLanguage() may need to load the
4919                 //   content to determine the page language!
4920                 $contentHandler = ContentHandler::getForTitle( $this );
4921                 $pageLang = $contentHandler->getPageViewLanguage( $this );
4922                 return $pageLang;
4923         }
4924
4925         /**
4926          * Get a list of rendered edit notices for this page.
4927          *
4928          * Array is keyed by the original message key, and values are rendered using parseAsBlock, so
4929          * they will already be wrapped in paragraphs.
4930          *
4931          * @since 1.21
4932          * @param int $oldid Revision ID that's being edited
4933          * @return array
4934          */
4935         public function getEditNotices( $oldid = 0 ) {
4936                 $notices = [];
4937
4938                 // Optional notice for the entire namespace
4939                 $editnotice_ns = 'editnotice-' . $this->getNamespace();
4940                 $msg = wfMessage( $editnotice_ns );
4941                 if ( $msg->exists() ) {
4942                         $html = $msg->parseAsBlock();
4943                         // Edit notices may have complex logic, but output nothing (T91715)
4944                         if ( trim( $html ) !== '' ) {
4945                                 $notices[$editnotice_ns] = Html::rawElement(
4946                                         'div',
4947                                         [ 'class' => [
4948                                                 'mw-editnotice',
4949                                                 'mw-editnotice-namespace',
4950                                                 Sanitizer::escapeClass( "mw-$editnotice_ns" )
4951                                         ] ],
4952                                         $html
4953                                 );
4954                         }
4955                 }
4956
4957                 if ( MWNamespace::hasSubpages( $this->getNamespace() ) ) {
4958                         // Optional notice for page itself and any parent page
4959                         $parts = explode( '/', $this->getDBkey() );
4960                         $editnotice_base = $editnotice_ns;
4961                         while ( count( $parts ) > 0 ) {
4962                                 $editnotice_base .= '-' . array_shift( $parts );
4963                                 $msg = wfMessage( $editnotice_base );
4964                                 if ( $msg->exists() ) {
4965                                         $html = $msg->parseAsBlock();
4966                                         if ( trim( $html ) !== '' ) {
4967                                                 $notices[$editnotice_base] = Html::rawElement(
4968                                                         'div',
4969                                                         [ 'class' => [
4970                                                                 'mw-editnotice',
4971                                                                 'mw-editnotice-base',
4972                                                                 Sanitizer::escapeClass( "mw-$editnotice_base" )
4973                                                         ] ],
4974                                                         $html
4975                                                 );
4976                                         }
4977                                 }
4978                         }
4979                 } else {
4980                         // Even if there are no subpages in namespace, we still don't want "/" in MediaWiki message keys
4981                         $editnoticeText = $editnotice_ns . '-' . strtr( $this->getDBkey(), '/', '-' );
4982                         $msg = wfMessage( $editnoticeText );
4983                         if ( $msg->exists() ) {
4984                                 $html = $msg->parseAsBlock();
4985                                 if ( trim( $html ) !== '' ) {
4986                                         $notices[$editnoticeText] = Html::rawElement(
4987                                                 'div',
4988                                                 [ 'class' => [
4989                                                         'mw-editnotice',
4990                                                         'mw-editnotice-page',
4991                                                         Sanitizer::escapeClass( "mw-$editnoticeText" )
4992                                                 ] ],
4993                                                 $html
4994                                         );
4995                                 }
4996                         }
4997                 }
4998
4999                 Hooks::run( 'TitleGetEditNotices', [ $this, $oldid, &$notices ] );
5000                 return $notices;
5001         }
5002
5003         /**
5004          * @return array
5005          */
5006         public function __sleep() {
5007                 return [
5008                         'mNamespace',
5009                         'mDbkeyform',
5010                         'mFragment',
5011                         'mInterwiki',
5012                         'mLocalInterwiki',
5013                         'mUserCaseDBKey',
5014                         'mDefaultNamespace',
5015                 ];
5016         }
5017
5018         public function __wakeup() {
5019                 $this->mArticleID = ( $this->mNamespace >= 0 ) ? -1 : 0;
5020                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
5021                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
5022         }
5023
5024 }