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