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         /**
 112          * @var string|bool Comma-separated set of permission keys
 113          * indicating who can move or edit the page from the page table, (pre 1.10) rows.
 114          * Edit and move sections are separated by a colon
 115          * Example: "edit=autoconfirmed,sysop:move=sysop"
 116          */
 117         protected $mOldRestrictions = false;
 118
 119         /** @var bool Cascade restrictions on this page to included templates and images? */
 120         public $mCascadeRestriction;
 121
 122         /** Caching the results of getCascadeProtectionSources */
 123         public $mCascadingRestrictions;
 124
 125         /** @var array When do the restrictions on this page expire? */
 126         protected $mRestrictionsExpiry = [];
 127
 128         /** @var bool Are cascading restrictions in effect on this page? */
 129         protected $mHasCascadingRestrictions;
 130
 131         /** @var array Where are the cascading restrictions coming from on this page? */
 132         public $mCascadeSources;
 133
 134         /** @var bool Boolean for initialisation on demand */
 135         public $mRestrictionsLoaded = false;
 136
 137         /** @var string Text form including namespace/interwiki, initialised on demand */
 138         protected $mPrefixedText = null;
 139
 140         /** @var mixed Cached value for getTitleProtection (create protection) */
 141         public $mTitleProtection;
 142
 143         /**
 144          * @var int Namespace index when there is no namespace. Don't change the
 145          *   following default, NS_MAIN is hardcoded in several places. See T2696.
 146          *   Zero except in {{transclusion}} tags.
 147          */
 148         public $mDefaultNamespace = NS_MAIN;
 149
 150         /** @var int The page length, 0 for special pages */
 151         protected $mLength = -1;
 152
 153         /** @var null Is the article at this title a redirect? */
 154         public $mRedirect = null;
 155
 156         /** @var array Associative array of user ID -> timestamp/false */
 157         private $mNotificationTimestamp = [];
 158
 159         /** @var bool Whether a page has any subpages */
 160         private $mHasSubpages;
 161
 162         /** @var bool The (string) language code of the page's language and content code. */
 163         private $mPageLanguage = false;
 164
 165         /** @var string|bool|null The page language code from the database, null if not saved in
 166          * the database or false if not loaded, yet. */
 167         private $mDbPageLanguage = false;
 168
 169         /** @var TitleValue A corresponding TitleValue object */
 170         private $mTitleValue = null;
 171
 172         /** @var bool Would deleting this page be a big deletion? */
 173         private $mIsBigDeletion = null;
 174         // @}
 175
 176         /**
 177          * B/C kludge: provide a TitleParser for use by Title.
 178          * Ideally, Title would have no methods that need this.
 179          * Avoid usage of this singleton by using TitleValue
 180          * and the associated services when possible.
 181          *
 182          * @return TitleFormatter
 183          */
 184         private static function getTitleFormatter() {
 185                 return MediaWikiServices::getInstance()->getTitleFormatter();
 186         }
 187
 188         /**
 189          * B/C kludge: provide an InterwikiLookup for use by Title.
 190          * Ideally, Title would have no methods that need this.
 191          * Avoid usage of this singleton by using TitleValue
 192          * and the associated services when possible.
 193          *
 194          * @return InterwikiLookup
 195          */
 196         private static function getInterwikiLookup() {
 197                 return MediaWikiServices::getInstance()->getInterwikiLookup();
 198         }
 199
 200         /**
 201          * @access protected
 202          */
 203         function __construct() {
 204         }
 205
 206         /**
 207          * Create a new Title from a prefixed DB key
 208          *
 209          * @param string $key The database key, which has underscores
 210          *      instead of spaces, possibly including namespace and
 211          *      interwiki prefixes
 212          * @return Title|null Title, or null on an error
 213          */
 214         public static function newFromDBkey( $key ) {
 215                 $t = new Title();
 216                 $t->mDbkeyform = $key;
 217
 218                 try {
 219                         $t->secureAndSplit();
 220                         return $t;
 221                 } catch ( MalformedTitleException $ex ) {
 222                         return null;
 223                 }
 224         }
 225
 226         /**
 227          * Create a new Title from a TitleValue
 228          *
 229          * @param TitleValue $titleValue Assumed to be safe.
 230          *
 231          * @return Title
 232          */
 233         public static function newFromTitleValue( TitleValue $titleValue ) {
 234                 return self::newFromLinkTarget( $titleValue );
 235         }
 236
 237         /**
 238          * Create a new Title from a LinkTarget
 239          *
 240          * @param LinkTarget $linkTarget Assumed to be safe.
 241          *
 242          * @return Title
 243          */
 244         public static function newFromLinkTarget( LinkTarget $linkTarget ) {
 245                 if ( $linkTarget instanceof Title ) {
 246                         // Special case if it's already a Title object
 247                         return $linkTarget;
 248                 }
 249                 return self::makeTitle(
 250                         $linkTarget->getNamespace(),
 251                         $linkTarget->getText(),
 252                         $linkTarget->getFragment(),
 253                         $linkTarget->getInterwiki()
 254                 );
 255         }
 256
 257         /**
 258          * Create a new Title from text, such as what one would find in a link. De-
 259          * codes any HTML entities in the text.
 260          *
 261          * Title objects returned by this method are guaranteed to be valid, and
 262          * thus return true from the isValid() method.
 263          *
 264          * @param string|int|null $text The link text; spaces, prefixes, and an
 265          *   initial ':' indicating the main namespace are accepted.
 266          * @param int $defaultNamespace The namespace to use if none is specified
 267          *   by a prefix.  If you want to force a specific namespace even if
 268          *   $text might begin with a namespace prefix, use makeTitle() or
 269          *   makeTitleSafe().
 270          * @throws InvalidArgumentException
 271          * @return Title|null Title or null on an error.
 272          */
 273         public static function newFromText( $text, $defaultNamespace = NS_MAIN ) {
 274                 // DWIM: Integers can be passed in here when page titles are used as array keys.
 275                 if ( $text !== null && !is_string( $text ) && !is_int( $text ) ) {
 276                         throw new InvalidArgumentException( '$text must be a string.' );
 277                 }
 278                 if ( $text === null ) {
 279                         return null;
 280                 }
 281
 282                 try {
 283                         return self::newFromTextThrow( strval( $text ), $defaultNamespace );
 284                 } catch ( MalformedTitleException $ex ) {
 285                         return null;
 286                 }
 287         }
 288
 289         /**
 290          * Like Title::newFromText(), but throws MalformedTitleException when the title is invalid,
 291          * rather than returning null.
 292          *
 293          * The exception subclasses encode detailed information about why the title is invalid.
 294          *
 295          * Title objects returned by this method are guaranteed to be valid, and
 296          * thus return true from the isValid() method.
 297          *
 298          * @see Title::newFromText
 299          *
 300          * @since 1.25
 301          * @param string $text Title text to check
 302          * @param int $defaultNamespace
 303          * @throws MalformedTitleException If the title is invalid
 304          * @return Title
 305          */
 306         public static function newFromTextThrow( $text, $defaultNamespace = NS_MAIN ) {
 307                 if ( is_object( $text ) ) {
 308                         throw new MWException( '$text must be a string, given an object' );
 309                 }
 310
 311                 $titleCache = self::getTitleCache();
 312
 313                 // Wiki pages often contain multiple links to the same page.
 314                 // Title normalization and parsing can become expensive on pages with many
 315                 // links, so we can save a little time by caching them.
 316                 // In theory these are value objects and won't get changed...
 317                 if ( $defaultNamespace == NS_MAIN ) {
 318                         $t = $titleCache->get( $text );
 319                         if ( $t ) {
 320                                 return $t;
 321                         }
 322                 }
 323
 324                 // Convert things like &eacute; &#257; or &#x3017; into normalized (T16952) text
 325                 $filteredText = Sanitizer::decodeCharReferencesAndNormalize( $text );
 326
 327                 $t = new Title();
 328                 $t->mDbkeyform = strtr( $filteredText, ' ', '_' );
 329                 $t->mDefaultNamespace = intval( $defaultNamespace );
 330
 331                 $t->secureAndSplit();
 332                 if ( $defaultNamespace == NS_MAIN ) {
 333                         $titleCache->set( $text, $t );
 334                 }
 335                 return $t;
 336         }
 337
 338         /**
 339          * THIS IS NOT THE FUNCTION YOU WANT. Use Title::newFromText().
 340          *
 341          * Example of wrong and broken code:
 342          * $title = Title::newFromURL( $wgRequest->getVal( 'title' ) );
 343          *
 344          * Example of right code:
 345          * $title = Title::newFromText( $wgRequest->getVal( 'title' ) );
 346          *
 347          * Create a new Title from URL-encoded text. Ensures that
 348          * the given title's length does not exceed the maximum.
 349          *
 350          * @param string $url The title, as might be taken from a URL
 351          * @return Title|null The new object, or null on an error
 352          */
 353         public static function newFromURL( $url ) {
 354                 $t = new Title();
 355
 356                 # For compatibility with old buggy URLs. "+" is usually not valid in titles,
 357                 # but some URLs used it as a space replacement and they still come
 358                 # from some external search tools.
 359                 if ( strpos( self::legalChars(), '+' ) === false ) {
 360                         $url = strtr( $url, '+', ' ' );
 361                 }
 362
 363                 $t->mDbkeyform = strtr( $url, ' ', '_' );
 364
 365                 try {
 366                         $t->secureAndSplit();
 367                         return $t;
 368                 } catch ( MalformedTitleException $ex ) {
 369                         return null;
 370                 }
 371         }
 372
 373         /**
 374          * @return HashBagOStuff
 375          */
 376         private static function getTitleCache() {
 377                 if ( self::$titleCache == null ) {
 378                         self::$titleCache = new HashBagOStuff( [ 'maxKeys' => self::CACHE_MAX ] );
 379                 }
 380                 return self::$titleCache;
 381         }
 382
 383         /**
 384          * Returns a list of fields that are to be selected for initializing Title
 385          * objects or LinkCache entries. Uses $wgContentHandlerUseDB to determine
 386          * whether to include page_content_model.
 387          *
 388          * @return array
 389          */
 390         protected static function getSelectFields() {
 391                 global $wgContentHandlerUseDB, $wgPageLanguageUseDB;
 392
 393                 $fields = [
 394                         'page_namespace', 'page_title', 'page_id',
 395                         'page_len', 'page_is_redirect', 'page_latest',
 396                 ];
 397
 398                 if ( $wgContentHandlerUseDB ) {
 399                         $fields[] = 'page_content_model';
 400                 }
 401
 402                 if ( $wgPageLanguageUseDB ) {
 403                         $fields[] = 'page_lang';
 404                 }
 405
 406                 return $fields;
 407         }
 408
 409         /**
 410          * Create a new Title from an article ID
 411          *
 412          * @param int $id The page_id corresponding to the Title to create
 413          * @param int $flags Use Title::GAID_FOR_UPDATE to use master
 414          * @return Title|null The new object, or null on an error
 415          */
 416         public static function newFromID( $id, $flags = 0 ) {
 417                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_REPLICA );
 418                 $row = $db->selectRow(
 419                         'page',
 420                         self::getSelectFields(),
 421                         [ 'page_id' => $id ],
 422                         __METHOD__
 423                 );
 424                 if ( $row !== false ) {
 425                         $title = self::newFromRow( $row );
 426                 } else {
 427                         $title = null;
 428                 }
 429                 return $title;
 430         }
 431
 432         /**
 433          * Make an array of titles from an array of IDs
 434          *
 435          * @param int[] $ids Array of IDs
 436          * @return Title[] Array of Titles
 437          */
 438         public static function newFromIDs( $ids ) {
 439                 if ( !count( $ids ) ) {
 440                         return [];
 441                 }
 442                 $dbr = wfGetDB( DB_REPLICA );
 443
 444                 $res = $dbr->select(
 445                         'page',
 446                         self::getSelectFields(),
 447                         [ 'page_id' => $ids ],
 448                         __METHOD__
 449                 );
 450
 451                 $titles = [];
 452                 foreach ( $res as $row ) {
 453                         $titles[] = self::newFromRow( $row );
 454                 }
 455                 return $titles;
 456         }
 457
 458         /**
 459          * Make a Title object from a DB row
 460          *
 461          * @param stdClass $row Object database row (needs at least page_title,page_namespace)
 462          * @return Title Corresponding Title
 463          */
 464         public static function newFromRow( $row ) {
 465                 $t = self::makeTitle( $row->page_namespace, $row->page_title );
 466                 $t->loadFromRow( $row );
 467                 return $t;
 468         }
 469
 470         /**
 471          * Load Title object fields from a DB row.
 472          * If false is given, the title will be treated as non-existing.
 473          *
 474          * @param stdClass|bool $row Database row
 475          */
 476         public function loadFromRow( $row ) {
 477                 if ( $row ) { // page found
 478                         if ( isset( $row->page_id ) ) {
 479                                 $this->mArticleID = (int)$row->page_id;
 480                         }
 481                         if ( isset( $row->page_len ) ) {
 482                                 $this->mLength = (int)$row->page_len;
 483                         }
 484                         if ( isset( $row->page_is_redirect ) ) {
 485                                 $this->mRedirect = (bool)$row->page_is_redirect;
 486                         }
 487                         if ( isset( $row->page_latest ) ) {
 488                                 $this->mLatestID = (int)$row->page_latest;
 489                         }
 490                         if ( !$this->mForcedContentModel && isset( $row->page_content_model ) ) {
 491                                 $this->mContentModel = strval( $row->page_content_model );
 492                         } elseif ( !$this->mForcedContentModel ) {
 493                                 $this->mContentModel = false; # initialized lazily in getContentModel()
 494                         }
 495                         if ( isset( $row->page_lang ) ) {
 496                                 $this->mDbPageLanguage = (string)$row->page_lang;
 497                         }
 498                         if ( isset( $row->page_restrictions ) ) {
 499                                 $this->mOldRestrictions = $row->page_restrictions;
 500                         }
 501                 } else { // page not found
 502                         $this->mArticleID = 0;
 503                         $this->mLength = 0;
 504                         $this->mRedirect = false;
 505                         $this->mLatestID = 0;
 506                         if ( !$this->mForcedContentModel ) {
 507                                 $this->mContentModel = false; # initialized lazily in getContentModel()
 508                         }
 509                 }
 510         }
 511
 512         /**
 513          * Create a new Title from a namespace index and a DB key.
 514          *
 515          * It's assumed that $ns and $title are safe, for instance when
 516          * they came directly from the database or a special page name,
 517          * not from user input.
 518          *
 519          * No validation is applied. For convenience, spaces are normalized
 520          * to underscores, so that e.g. user_text fields can be used directly.
 521          *
 522          * @note This method may return Title objects that are "invalid"
 523          * according to the isValid() method. This is usually caused by
 524          * configuration changes: e.g. a namespace that was once defined is
 525          * no longer configured, or a character that was once allowed in
 526          * titles is now forbidden.
 527          *
 528          * @param int $ns The namespace of the article
 529          * @param string $title The unprefixed database key form
 530          * @param string $fragment The link fragment (after the "#")
 531          * @param string $interwiki The interwiki prefix
 532          * @return Title The new object
 533          */
 534         public static function makeTitle( $ns, $title, $fragment = '', $interwiki = '' ) {
 535                 $t = new Title();
 536                 $t->mInterwiki = $interwiki;
 537                 $t->mFragment = $fragment;
 538                 $t->mNamespace = $ns = intval( $ns );
 539                 $t->mDbkeyform = strtr( $title, ' ', '_' );
 540                 $t->mArticleID = ( $ns >= 0 ) ? -1 : 0;
 541                 $t->mUrlform = wfUrlencode( $t->mDbkeyform );
 542                 $t->mTextform = strtr( $title, '_', ' ' );
 543                 $t->mContentModel = false; # initialized lazily in getContentModel()
 544                 return $t;
 545         }
 546
 547         /**
 548          * Create a new Title from a namespace index and a DB key.
 549          * The parameters will be checked for validity, which is a bit slower
 550          * than makeTitle() but safer for user-provided data.
 551          *
 552          * Title objects returned by makeTitleSafe() are guaranteed to be valid,
 553          * that is, they return true from the isValid() method. If no valid Title
 554          * can be constructed from the input, this method returns null.
 555          *
 556          * @param int $ns The namespace of the article
 557          * @param string $title Database key form
 558          * @param string $fragment The link fragment (after the "#")
 559          * @param string $interwiki Interwiki prefix
 560          * @return Title|null The new object, or null on an error
 561          */
 562         public static function makeTitleSafe( $ns, $title, $fragment = '', $interwiki = '' ) {
 563                 // NOTE: ideally, this would just call makeTitle() and then isValid(),
 564                 // but presently, that means more overhead on a potential performance hotspot.
 565
 566                 if ( !MWNamespace::exists( $ns ) ) {
 567                         return null;
 568                 }
 569
 570                 $t = new Title();
 571                 $t->mDbkeyform = self::makeName( $ns, $title, $fragment, $interwiki, true );
 572
 573                 try {
 574                         $t->secureAndSplit();
 575                         return $t;
 576                 } catch ( MalformedTitleException $ex ) {
 577                         return null;
 578                 }
 579         }
 580
 581         /**
 582          * Create a new Title for the Main Page
 583          *
 584          * @return Title The new object
 585          */
 586         public static function newMainPage() {
 587                 $title = self::newFromText( wfMessage( 'mainpage' )->inContentLanguage()->text() );
 588                 // Don't give fatal errors if the message is broken
 589                 if ( !$title ) {
 590                         $title = self::newFromText( 'Main Page' );
 591                 }
 592                 return $title;
 593         }
 594
 595         /**
 596          * Get the prefixed DB key associated with an ID
 597          *
 598          * @param int $id The page_id of the article
 599          * @return Title|null An object representing the article, or null if no such article was found
 600          */
 601         public static function nameOf( $id ) {
 602                 $dbr = wfGetDB( DB_REPLICA );
 603
 604                 $s = $dbr->selectRow(
 605                         'page',
 606                         [ 'page_namespace', 'page_title' ],
 607                         [ 'page_id' => $id ],
 608                         __METHOD__
 609                 );
 610                 if ( $s === false ) {
 611                         return null;
 612                 }
 613
 614                 $n = self::makeName( $s->page_namespace, $s->page_title );
 615                 return $n;
 616         }
 617
 618         /**
 619          * Get a regex character class describing the legal characters in a link
 620          *
 621          * @return string The list of characters, not delimited
 622          */
 623         public static function legalChars() {
 624                 global $wgLegalTitleChars;
 625                 return $wgLegalTitleChars;
 626         }
 627
 628         /**
 629          * Utility method for converting a character sequence from bytes to Unicode.
 630          *
 631          * Primary usecase being converting $wgLegalTitleChars to a sequence usable in
 632          * javascript, as PHP uses UTF-8 bytes where javascript uses Unicode code units.
 633          *
 634          * @param string $byteClass
 635          * @return string
 636          */
 637         public static function convertByteClassToUnicodeClass( $byteClass ) {
 638                 $length = strlen( $byteClass );
 639                 // Input token queue
 640                 $x0 = $x1 = $x2 = '';
 641                 // Decoded queue
 642                 $d0 = $d1 = $d2 = '';
 643                 // Decoded integer codepoints
 644                 $ord0 = $ord1 = $ord2 = 0;
 645                 // Re-encoded queue
 646                 $r0 = $r1 = $r2 = '';
 647                 // Output
 648                 $out = '';
 649                 // Flags
 650                 $allowUnicode = false;
 651                 for ( $pos = 0; $pos < $length; $pos++ ) {
 652                         // Shift the queues down
 653                         $x2 = $x1;
 654                         $x1 = $x0;
 655                         $d2 = $d1;
 656                         $d1 = $d0;
 657                         $ord2 = $ord1;
 658                         $ord1 = $ord0;
 659                         $r2 = $r1;
 660                         $r1 = $r0;
 661                         // Load the current input token and decoded values
 662                         $inChar = $byteClass[$pos];
 663                         if ( $inChar == '\\' ) {
 664                                 if ( preg_match( '/x([0-9a-fA-F]{2})/A', $byteClass, $m, 0, $pos + 1 ) ) {
 665                                         $x0 = $inChar . $m[0];
 666                                         $d0 = chr( hexdec( $m[1] ) );
 667                                         $pos += strlen( $m[0] );
 668                                 } elseif ( preg_match( '/[0-7]{3}/A', $byteClass, $m, 0, $pos + 1 ) ) {
 669                                         $x0 = $inChar . $m[0];
 670                                         $d0 = chr( octdec( $m[0] ) );
 671                                         $pos += strlen( $m[0] );
 672                                 } elseif ( $pos + 1 >= $length ) {
 673                                         $x0 = $d0 = '\\';
 674                                 } else {
 675                                         $d0 = $byteClass[$pos + 1];
 676                                         $x0 = $inChar . $d0;
 677                                         $pos += 1;
 678                                 }
 679                         } else {
 680                                 $x0 = $d0 = $inChar;
 681                         }
 682                         $ord0 = ord( $d0 );
 683                         // Load the current re-encoded value
 684                         if ( $ord0 < 32 || $ord0 == 0x7f ) {
 685                                 $r0 = sprintf( '\x%02x', $ord0 );
 686                         } elseif ( $ord0 >= 0x80 ) {
 687                                 // Allow unicode if a single high-bit character appears
 688                                 $r0 = sprintf( '\x%02x', $ord0 );
 689                                 $allowUnicode = true;
 690                         } elseif ( strpos( '-\\[]^', $d0 ) !== false ) {
 691                                 $r0 = '\\' . $d0;
 692                         } else {
 693                                 $r0 = $d0;
 694                         }
 695                         // Do the output
 696                         if ( $x0 !== '' && $x1 === '-' && $x2 !== '' ) {
 697                                 // Range
 698                                 if ( $ord2 > $ord0 ) {
 699                                         // Empty range
 700                                 } elseif ( $ord0 >= 0x80 ) {
 701                                         // Unicode range
 702                                         $allowUnicode = true;
 703                                         if ( $ord2 < 0x80 ) {
 704                                                 // Keep the non-unicode section of the range
 705                                                 $out .= "$r2-\\x7F";
 706                                         }
 707                                 } else {
 708                                         // Normal range
 709                                         $out .= "$r2-$r0";
 710                                 }
 711                                 // Reset state to the initial value
 712                                 $x0 = $x1 = $d0 = $d1 = $r0 = $r1 = '';
 713                         } elseif ( $ord2 < 0x80 ) {
 714                                 // ASCII character
 715                                 $out .= $r2;
 716                         }
 717                 }
 718                 if ( $ord1 < 0x80 ) {
 719                         $out .= $r1;
 720                 }
 721                 if ( $ord0 < 0x80 ) {
 722                         $out .= $r0;
 723                 }
 724                 if ( $allowUnicode ) {
 725                         $out .= '\u0080-\uFFFF';
 726                 }
 727                 return $out;
 728         }
 729
 730         /**
 731          * Make a prefixed DB key from a DB key and a namespace index
 732          *
 733          * @param int $ns Numerical representation of the namespace
 734          * @param string $title The DB key form the title
 735          * @param string $fragment The link fragment (after the "#")
 736          * @param string $interwiki The interwiki prefix
 737          * @param bool $canonicalNamespace If true, use the canonical name for
 738          *   $ns instead of the localized version.
 739          * @return string The prefixed form of the title
 740          */
 741         public static function makeName( $ns, $title, $fragment = '', $interwiki = '',
 742                 $canonicalNamespace = false
 743         ) {
 744                 global $wgContLang;
 745
 746                 if ( $canonicalNamespace ) {
 747                         $namespace = MWNamespace::getCanonicalName( $ns );
 748                 } else {
 749                         $namespace = $wgContLang->getNsText( $ns );
 750                 }
 751                 $name = $namespace == '' ? $title : "$namespace:$title";
 752                 if ( strval( $interwiki ) != '' ) {
 753                         $name = "$interwiki:$name";
 754                 }
 755                 if ( strval( $fragment ) != '' ) {
 756                         $name .= '#' . $fragment;
 757                 }
 758                 return $name;
 759         }
 760
 761         /**
 762          * Escape a text fragment, say from a link, for a URL
 763          *
 764          * @deprecated since 1.30, use Sanitizer::escapeIdForLink() or escapeIdForExternalInterwiki()
 765          *
 766          * @param string $fragment Containing a URL or link fragment (after the "#")
 767          * @return string Escaped string
 768          */
 769         static function escapeFragmentForURL( $fragment ) {
 770                 wfDeprecated( __METHOD__, '1.30' );
 771                 # Note that we don't urlencode the fragment.  urlencoded Unicode
 772                 # fragments appear not to work in IE (at least up to 7) or in at least
 773                 # one version of Opera 9.x.  The W3C validator, for one, doesn't seem
 774                 # to care if they aren't encoded.
 775                 return Sanitizer::escapeId( $fragment, 'noninitial' );
 776         }
 777
 778         /**
 779          * Callback for usort() to do title sorts by (namespace, title)
 780          *
 781          * @param LinkTarget $a
 782          * @param LinkTarget $b
 783          *
 784          * @return int Result of string comparison, or namespace comparison
 785          */
 786         public static function compare( LinkTarget $a, LinkTarget $b ) {
 787                 if ( $a->getNamespace() == $b->getNamespace() ) {
 788                         return strcmp( $a->getText(), $b->getText() );
 789                 } else {
 790                         return $a->getNamespace() - $b->getNamespace();
 791                 }
 792         }
 793
 794         /**
 795          * Returns true if the title is valid, false if it is invalid.
 796          *
 797          * Valid titles can be round-tripped via makeTitleSafe() and newFromText().
 798          * Invalid titles may get returned from makeTitle(), and it may be useful to
 799          * allow them to exist, e.g. in order to process log entries about pages in
 800          * namespaces that belong to extensions that are no longer installed.
 801          *
 802          * @note This method is relatively expensive. When constructing Title
 803          * objects that need to be valid, use an instantiator method that is guaranteed
 804          * to return valid titles, such as makeTitleSafe() or newFromText().
 805          *
 806          * @return bool
 807          */
 808         public function isValid() {
 809                 $ns = $this->getNamespace();
 810
 811                 if ( !MWNamespace::exists( $ns ) ) {
 812                         return false;
 813                 }
 814
 815                 try {
 816                         $parser = MediaWikiServices::getInstance()->getTitleParser();
 817                         $parser->parseTitle( $this->getDBkey(), $ns );
 818                         return true;
 819                 } catch ( MalformedTitleException $ex ) {
 820                         return false;
 821                 }
 822         }
 823
 824         /**
 825          * Determine whether the object refers to a page within
 826          * this project (either this wiki or a wiki with a local
 827          * interwiki, see https://www.mediawiki.org/wiki/Manual:Interwiki_table#iw_local )
 828          *
 829          * @return bool True if this is an in-project interwiki link or a wikilink, false otherwise
 830          */
 831         public function isLocal() {
 832                 if ( $this->isExternal() ) {
 833                         $iw = self::getInterwikiLookup()->fetch( $this->mInterwiki );
 834                         if ( $iw ) {
 835                                 return $iw->isLocal();
 836                         }
 837                 }
 838                 return true;
 839         }
 840
 841         /**
 842          * Is this Title interwiki?
 843          *
 844          * @return bool
 845          */
 846         public function isExternal() {
 847                 return $this->mInterwiki !== '';
 848         }
 849
 850         /**
 851          * Get the interwiki prefix
 852          *
 853          * Use Title::isExternal to check if a interwiki is set
 854          *
 855          * @return string Interwiki prefix
 856          */
 857         public function getInterwiki() {
 858                 return $this->mInterwiki;
 859         }
 860
 861         /**
 862          * Was this a local interwiki link?
 863          *
 864          * @return bool
 865          */
 866         public function wasLocalInterwiki() {
 867                 return $this->mLocalInterwiki;
 868         }
 869
 870         /**
 871          * Determine whether the object refers to a page within
 872          * this project and is transcludable.
 873          *
 874          * @return bool True if this is transcludable
 875          */
 876         public function isTrans() {
 877                 if ( !$this->isExternal() ) {
 878                         return false;
 879                 }
 880
 881                 return self::getInterwikiLookup()->fetch( $this->mInterwiki )->isTranscludable();
 882         }
 883
 884         /**
 885          * Returns the DB name of the distant wiki which owns the object.
 886          *
 887          * @return string|false The DB name
 888          */
 889         public function getTransWikiID() {
 890                 if ( !$this->isExternal() ) {
 891                         return false;
 892                 }
 893
 894                 return self::getInterwikiLookup()->fetch( $this->mInterwiki )->getWikiID();
 895         }
 896
 897         /**
 898          * Get a TitleValue object representing this Title.
 899          *
 900          * @note Not all valid Titles have a corresponding valid TitleValue
 901          * (e.g. TitleValues cannot represent page-local links that have a
 902          * fragment but no title text).
 903          *
 904          * @return TitleValue|null
 905          */
 906         public function getTitleValue() {
 907                 if ( $this->mTitleValue === null ) {
 908                         try {
 909                                 $this->mTitleValue = new TitleValue(
 910                                         $this->getNamespace(),
 911                                         $this->getDBkey(),
 912                                         $this->getFragment(),
 913                                         $this->getInterwiki()
 914                                 );
 915                         } catch ( InvalidArgumentException $ex ) {
 916                                 wfDebug( __METHOD__ . ': Can\'t create a TitleValue for [[' .
 917                                         $this->getPrefixedText() . ']]: ' . $ex->getMessage() . "\n" );
 918                         }
 919                 }
 920
 921                 return $this->mTitleValue;
 922         }
 923
 924         /**
 925          * Get the text form (spaces not underscores) of the main part
 926          *
 927          * @return string Main part of the title
 928          */
 929         public function getText() {
 930                 return $this->mTextform;
 931         }
 932
 933         /**
 934          * Get the URL-encoded form of the main part
 935          *
 936          * @return string Main part of the title, URL-encoded
 937          */
 938         public function getPartialURL() {
 939                 return $this->mUrlform;
 940         }
 941
 942         /**
 943          * Get the main part with underscores
 944          *
 945          * @return string Main part of the title, with underscores
 946          */
 947         public function getDBkey() {
 948                 return $this->mDbkeyform;
 949         }
 950
 951         /**
 952          * Get the DB key with the initial letter case as specified by the user
 953          *
 954          * @return string DB key
 955          */
 956         function getUserCaseDBKey() {
 957                 if ( !is_null( $this->mUserCaseDBKey ) ) {
 958                         return $this->mUserCaseDBKey;
 959                 } else {
 960                         // If created via makeTitle(), $this->mUserCaseDBKey is not set.
 961                         return $this->mDbkeyform;
 962                 }
 963         }
 964
 965         /**
 966          * Get the namespace index, i.e. one of the NS_xxxx constants.
 967          *
 968          * @return int Namespace index
 969          */
 970         public function getNamespace() {
 971                 return $this->mNamespace;
 972         }
 973
 974         /**
 975          * Get the page's content model id, see the CONTENT_MODEL_XXX constants.
 976          *
 977          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
 978          * @return string Content model id
 979          */
 980         public function getContentModel( $flags = 0 ) {
 981                 if ( !$this->mForcedContentModel
 982                         && ( !$this->mContentModel || $flags === self::GAID_FOR_UPDATE )
 983                         && $this->getArticleID( $flags )
 984                 ) {
 985                         $linkCache = LinkCache::singleton();
 986                         $linkCache->addLinkObj( $this ); # in case we already had an article ID
 987                         $this->mContentModel = $linkCache->getGoodLinkFieldObj( $this, 'model' );
 988                 }
 989
 990                 if ( !$this->mContentModel ) {
 991                         $this->mContentModel = ContentHandler::getDefaultModelFor( $this );
 992                 }
 993
 994                 return $this->mContentModel;
 995         }
 996
 997         /**
 998          * Convenience method for checking a title's content model name
 999          *
1000          * @param string $id The content model ID (use the CONTENT_MODEL_XXX constants).
1001          * @return bool True if $this->getContentModel() == $id
1002          */
1003         public function hasContentModel( $id ) {
1004                 return $this->getContentModel() == $id;
1005         }
1006
1007         /**
1008          * Set a proposed content model for the page for permissions
1009          * checking. This does not actually change the content model
1010          * of a title!
1011          *
1012          * Additionally, you should make sure you've checked
1013          * ContentHandler::canBeUsedOn() first.
1014          *
1015          * @since 1.28
1016          * @param string $model CONTENT_MODEL_XXX constant
1017          */
1018         public function setContentModel( $model ) {
1019                 $this->mContentModel = $model;
1020                 $this->mForcedContentModel = true;
1021         }
1022
1023         /**
1024          * Get the namespace text
1025          *
1026          * @return string|false Namespace text
1027          */
1028         public function getNsText() {
1029                 if ( $this->isExternal() ) {
1030                         // This probably shouldn't even happen, except for interwiki transclusion.
1031                         // If possible, use the canonical name for the foreign namespace.
1032                         $nsText = MWNamespace::getCanonicalName( $this->mNamespace );
1033                         if ( $nsText !== false ) {
1034                                 return $nsText;
1035                         }
1036                 }
1037
1038                 try {
1039                         $formatter = self::getTitleFormatter();
1040                         return $formatter->getNamespaceName( $this->mNamespace, $this->mDbkeyform );
1041                 } catch ( InvalidArgumentException $ex ) {
1042                         wfDebug( __METHOD__ . ': ' . $ex->getMessage() . "\n" );
1043                         return false;
1044                 }
1045         }
1046
1047         /**
1048          * Get the namespace text of the subject (rather than talk) page
1049          *
1050          * @return string Namespace text
1051          */
1052         public function getSubjectNsText() {
1053                 global $wgContLang;
1054                 return $wgContLang->getNsText( MWNamespace::getSubject( $this->mNamespace ) );
1055         }
1056
1057         /**
1058          * Get the namespace text of the talk page
1059          *
1060          * @return string Namespace text
1061          */
1062         public function getTalkNsText() {
1063                 global $wgContLang;
1064                 return $wgContLang->getNsText( MWNamespace::getTalk( $this->mNamespace ) );
1065         }
1066
1067         /**
1068          * Can this title have a corresponding talk page?
1069          *
1070          * @deprecated since 1.30, use canHaveTalkPage() instead.
1071          *
1072          * @return bool True if this title either is a talk page or can have a talk page associated.
1073          */
1074         public function canTalk() {
1075                 return $this->canHaveTalkPage();
1076         }
1077
1078         /**
1079          * Can this title have a corresponding talk page?
1080          *
1081          * @see MWNamespace::hasTalkNamespace
1082          * @since 1.30
1083          *
1084          * @return bool True if this title either is a talk page or can have a talk page associated.
1085          */
1086         public function canHaveTalkPage() {
1087                 return MWNamespace::hasTalkNamespace( $this->mNamespace );
1088         }
1089
1090         /**
1091          * Is this in a namespace that allows actual pages?
1092          *
1093          * @return bool
1094          */
1095         public function canExist() {
1096                 return $this->mNamespace >= NS_MAIN;
1097         }
1098
1099         /**
1100          * Can this title be added to a user's watchlist?
1101          *
1102          * @return bool
1103          */
1104         public function isWatchable() {
1105                 return !$this->isExternal() && MWNamespace::isWatchable( $this->getNamespace() );
1106         }
1107
1108         /**
1109          * Returns true if this is a special page.
1110          *
1111          * @return bool
1112          */
1113         public function isSpecialPage() {
1114                 return $this->getNamespace() == NS_SPECIAL;
1115         }
1116
1117         /**
1118          * Returns true if this title resolves to the named special page
1119          *
1120          * @param string $name The special page name
1121          * @return bool
1122          */
1123         public function isSpecial( $name ) {
1124                 if ( $this->isSpecialPage() ) {
1125                         list( $thisName, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $this->getDBkey() );
1126                         if ( $name == $thisName ) {
1127                                 return true;
1128                         }
1129                 }
1130                 return false;
1131         }
1132
1133         /**
1134          * If the Title refers to a special page alias which is not the local default, resolve
1135          * the alias, and localise the name as necessary.  Otherwise, return $this
1136          *
1137          * @return Title
1138          */
1139         public function fixSpecialName() {
1140                 if ( $this->isSpecialPage() ) {
1141                         list( $canonicalName, $par ) = SpecialPageFactory::resolveAlias( $this->mDbkeyform );
1142                         if ( $canonicalName ) {
1143                                 $localName = SpecialPageFactory::getLocalNameFor( $canonicalName, $par );
1144                                 if ( $localName != $this->mDbkeyform ) {
1145                                         return self::makeTitle( NS_SPECIAL, $localName );
1146                                 }
1147                         }
1148                 }
1149                 return $this;
1150         }
1151
1152         /**
1153          * Returns true if the title is inside the specified namespace.
1154          *
1155          * Please make use of this instead of comparing to getNamespace()
1156          * This function is much more resistant to changes we may make
1157          * to namespaces than code that makes direct comparisons.
1158          * @param int $ns The namespace
1159          * @return bool
1160          * @since 1.19
1161          */
1162         public function inNamespace( $ns ) {
1163                 return MWNamespace::equals( $this->getNamespace(), $ns );
1164         }
1165
1166         /**
1167          * Returns true if the title is inside one of the specified namespaces.
1168          *
1169          * @param int|int[] $namespaces,... The namespaces to check for
1170          * @return bool
1171          * @since 1.19
1172          */
1173         public function inNamespaces( /* ... */ ) {
1174                 $namespaces = func_get_args();
1175                 if ( count( $namespaces ) > 0 && is_array( $namespaces[0] ) ) {
1176                         $namespaces = $namespaces[0];
1177                 }
1178
1179                 foreach ( $namespaces as $ns ) {
1180                         if ( $this->inNamespace( $ns ) ) {
1181                                 return true;
1182                         }
1183                 }
1184
1185                 return false;
1186         }
1187
1188         /**
1189          * Returns true if the title has the same subject namespace as the
1190          * namespace specified.
1191          * For example this method will take NS_USER and return true if namespace
1192          * is either NS_USER or NS_USER_TALK since both of them have NS_USER
1193          * as their subject namespace.
1194          *
1195          * This is MUCH simpler than individually testing for equivalence
1196          * against both NS_USER and NS_USER_TALK, and is also forward compatible.
1197          * @since 1.19
1198          * @param int $ns
1199          * @return bool
1200          */
1201         public function hasSubjectNamespace( $ns ) {
1202                 return MWNamespace::subjectEquals( $this->getNamespace(), $ns );
1203         }
1204
1205         /**
1206          * Is this Title in a namespace which contains content?
1207          * In other words, is this a content page, for the purposes of calculating
1208          * statistics, etc?
1209          *
1210          * @return bool
1211          */
1212         public function isContentPage() {
1213                 return MWNamespace::isContent( $this->getNamespace() );
1214         }
1215
1216         /**
1217          * Would anybody with sufficient privileges be able to move this page?
1218          * Some pages just aren't movable.
1219          *
1220          * @return bool
1221          */
1222         public function isMovable() {
1223                 if ( !MWNamespace::isMovable( $this->getNamespace() ) || $this->isExternal() ) {
1224                         // Interwiki title or immovable namespace. Hooks don't get to override here
1225                         return false;
1226                 }
1227
1228                 $result = true;
1229                 Hooks::run( 'TitleIsMovable', [ $this, &$result ] );
1230                 return $result;
1231         }
1232
1233         /**
1234          * Is this the mainpage?
1235          * @note Title::newFromText seems to be sufficiently optimized by the title
1236          * cache that we don't need to over-optimize by doing direct comparisons and
1237          * accidentally creating new bugs where $title->equals( Title::newFromText() )
1238          * ends up reporting something differently than $title->isMainPage();
1239          *
1240          * @since 1.18
1241          * @return bool
1242          */
1243         public function isMainPage() {
1244                 return $this->equals( self::newMainPage() );
1245         }
1246
1247         /**
1248          * Is this a subpage?
1249          *
1250          * @return bool
1251          */
1252         public function isSubpage() {
1253                 return MWNamespace::hasSubpages( $this->mNamespace )
1254                         ? strpos( $this->getText(), '/' ) !== false
1255                         : false;
1256         }
1257
1258         /**
1259          * Is this a conversion table for the LanguageConverter?
1260          *
1261          * @return bool
1262          */
1263         public function isConversionTable() {
1264                 // @todo ConversionTable should become a separate content model.
1265
1266                 return $this->getNamespace() == NS_MEDIAWIKI &&
1267                         strpos( $this->getText(), 'Conversiontable/' ) === 0;
1268         }
1269
1270         /**
1271          * Does that page contain wikitext, or it is JS, CSS or whatever?
1272          *
1273          * @return bool
1274          */
1275         public function isWikitextPage() {
1276                 return $this->hasContentModel( CONTENT_MODEL_WIKITEXT );
1277         }
1278
1279         /**
1280          * Could this MediaWiki namespace page contain custom CSS, JSON, or JavaScript for the
1281          * global UI. This is generally true for pages in the MediaWiki namespace having
1282          * CONTENT_MODEL_CSS, CONTENT_MODEL_JSON, or CONTENT_MODEL_JAVASCRIPT.
1283          *
1284          * This method does *not* return true for per-user JS/JSON/CSS. Use isUserConfigPage()
1285          * for that!
1286          *
1287          * Note that this method should not return true for pages that contain and show
1288          * "inactive" CSS, JSON, or JS.
1289          *
1290          * @return bool
1291          * @since 1.31
1292          */
1293         public function isSiteConfigPage() {
1294                 return (
1295                         NS_MEDIAWIKI == $this->mNamespace
1296                         && (
1297                                 $this->hasContentModel( CONTENT_MODEL_CSS )
1298                                 || $this->hasContentModel( CONTENT_MODEL_JSON )
1299                                 || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT )
1300                         )
1301                 );
1302         }
1303
1304         /**
1305          * @return bool
1306          * @deprecated Since 1.31; use ::isSiteConfigPage() instead (which also checks for JSON pages)
1307          */
1308         public function isCssOrJsPage() {
1309                 wfDeprecated( __METHOD__, '1.31' );
1310                 return ( NS_MEDIAWIKI == $this->mNamespace
1311                                 && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1312                                         || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) ) );
1313         }
1314
1315         /**
1316          * Is this a "config" (.css, .json, or .js) sub-page of a user page?
1317          *
1318          * @return bool
1319          * @since 1.31
1320          */
1321         public function isUserConfigPage() {
1322                 return (
1323                         NS_USER == $this->mNamespace
1324                         && $this->isSubpage()
1325                         && (
1326                                 $this->hasContentModel( CONTENT_MODEL_CSS )
1327                                 || $this->hasContentModel( CONTENT_MODEL_JSON )
1328                                 || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT )
1329                         )
1330                 );
1331         }
1332
1333         /**
1334          * @return bool
1335          * @deprecated Since 1.31; use ::isUserConfigPage() instead (which also checks for JSON pages)
1336          */
1337         public function isCssJsSubpage() {
1338                 wfDeprecated( __METHOD__, '1.31' );
1339                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1340                                 && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1341                                         || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) ) );
1342         }
1343
1344         /**
1345          * Trim down a .css, .json, or .js subpage title to get the corresponding skin name
1346          *
1347          * @return string Containing skin name from .css, .json, or .js subpage title
1348          * @since 1.31
1349          */
1350         public function getSkinFromConfigSubpage() {
1351                 $subpage = explode( '/', $this->mTextform );
1352                 $subpage = $subpage[count( $subpage ) - 1];
1353                 $lastdot = strrpos( $subpage, '.' );
1354                 if ( $lastdot === false ) {
1355                         return $subpage; # Never happens: only called for names ending in '.css'/'.json'/'.js'
1356                 }
1357                 return substr( $subpage, 0, $lastdot );
1358         }
1359
1360         /**
1361          * @deprecated Since 1.31; use ::getSkinFromConfigSubpage() instead
1362          * @return string Containing skin name from .css, .json, or .js subpage title
1363          */
1364         public function getSkinFromCssJsSubpage() {
1365                 wfDeprecated( __METHOD__, '1.31' );
1366                 return $this->getSkinFromConfigSubpage();
1367         }
1368
1369         /**
1370          * Is this a CSS "config" sub-page of a user page?
1371          *
1372          * @return bool
1373          * @since 1.31
1374          */
1375         public function isUserCssConfigPage() {
1376                 return (
1377                         NS_USER == $this->mNamespace
1378                         && $this->isSubpage()
1379                         && $this->hasContentModel( CONTENT_MODEL_CSS )
1380                 );
1381         }
1382
1383         /**
1384          * @deprecated Since 1.31; use ::isUserCssConfigPage()
1385          * @return bool
1386          */
1387         public function isCssSubpage() {
1388                 wfDeprecated( __METHOD__, '1.31' );
1389                 return $this->isUserCssConfigPage();
1390         }
1391
1392         /**
1393          * Is this a JSON "config" sub-page of a user page?
1394          *
1395          * @return bool
1396          * @since 1.31
1397          */
1398         public function isUserJsonConfigPage() {
1399                 return (
1400                         NS_USER == $this->mNamespace
1401                         && $this->isSubpage()
1402                         && $this->hasContentModel( CONTENT_MODEL_JSON )
1403                 );
1404         }
1405
1406         /**
1407          * Is this a JS "config" sub-page of a user page?
1408          *
1409          * @return bool
1410          * @since 1.31
1411          */
1412         public function isUserJsConfigPage() {
1413                 return (
1414                         NS_USER == $this->mNamespace
1415                         && $this->isSubpage()
1416                         && $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT )
1417                 );
1418         }
1419
1420         /**
1421          * @deprecated Since 1.31; use ::isUserJsConfigPage()
1422          * @return bool
1423          */
1424         public function isJsSubpage() {
1425                 wfDeprecated( __METHOD__, '1.31' );
1426                 return $this->isUserJsConfigPage();
1427         }
1428
1429         /**
1430          * Is this a talk page of some sort?
1431          *
1432          * @return bool
1433          */
1434         public function isTalkPage() {
1435                 return MWNamespace::isTalk( $this->getNamespace() );
1436         }
1437
1438         /**
1439          * Get a Title object associated with the talk page of this article
1440          *
1441          * @return Title The object for the talk page
1442          */
1443         public function getTalkPage() {
1444                 return self::makeTitle( MWNamespace::getTalk( $this->getNamespace() ), $this->getDBkey() );
1445         }
1446
1447         /**
1448          * Get a Title object associated with the talk page of this article,
1449          * if such a talk page can exist.
1450          *
1451          * @since 1.30
1452          *
1453          * @return Title|null The object for the talk page,
1454          *         or null if no associated talk page can exist, according to canHaveTalkPage().
1455          */
1456         public function getTalkPageIfDefined() {
1457                 if ( !$this->canHaveTalkPage() ) {
1458                         return null;
1459                 }
1460
1461                 return $this->getTalkPage();
1462         }
1463
1464         /**
1465          * Get a title object associated with the subject page of this
1466          * talk page
1467          *
1468          * @return Title The object for the subject page
1469          */
1470         public function getSubjectPage() {
1471                 // Is this the same title?
1472                 $subjectNS = MWNamespace::getSubject( $this->getNamespace() );
1473                 if ( $this->getNamespace() == $subjectNS ) {
1474                         return $this;
1475                 }
1476                 return self::makeTitle( $subjectNS, $this->getDBkey() );
1477         }
1478
1479         /**
1480          * Get the other title for this page, if this is a subject page
1481          * get the talk page, if it is a subject page get the talk page
1482          *
1483          * @since 1.25
1484          * @throws MWException If the page doesn't have an other page
1485          * @return Title
1486          */
1487         public function getOtherPage() {
1488                 if ( $this->isSpecialPage() ) {
1489                         throw new MWException( 'Special pages cannot have other pages' );
1490                 }
1491                 if ( $this->isTalkPage() ) {
1492                         return $this->getSubjectPage();
1493                 } else {
1494                         if ( !$this->canHaveTalkPage() ) {
1495                                 throw new MWException( "{$this->getPrefixedText()} does not have an other page" );
1496                         }
1497                         return $this->getTalkPage();
1498                 }
1499         }
1500
1501         /**
1502          * Get the default namespace index, for when there is no namespace
1503          *
1504          * @return int Default namespace index
1505          */
1506         public function getDefaultNamespace() {
1507                 return $this->mDefaultNamespace;
1508         }
1509
1510         /**
1511          * Get the Title fragment (i.e.\ the bit after the #) in text form
1512          *
1513          * Use Title::hasFragment to check for a fragment
1514          *
1515          * @return string Title fragment
1516          */
1517         public function getFragment() {
1518                 return $this->mFragment;
1519         }
1520
1521         /**
1522          * Check if a Title fragment is set
1523          *
1524          * @return bool
1525          * @since 1.23
1526          */
1527         public function hasFragment() {
1528                 return $this->mFragment !== '';
1529         }
1530
1531         /**
1532          * Get the fragment in URL form, including the "#" character if there is one
1533          *
1534          * @return string Fragment in URL form
1535          */
1536         public function getFragmentForURL() {
1537                 if ( !$this->hasFragment() ) {
1538                         return '';
1539                 } elseif ( $this->isExternal()
1540                         && !self::getInterwikiLookup()->fetch( $this->mInterwiki )->isLocal()
1541                 ) {
1542                         return '#' . Sanitizer::escapeIdForExternalInterwiki( $this->getFragment() );
1543                 }
1544                 return '#' . Sanitizer::escapeIdForLink( $this->getFragment() );
1545         }
1546
1547         /**
1548          * Set the fragment for this title. Removes the first character from the
1549          * specified fragment before setting, so it assumes you're passing it with
1550          * an initial "#".
1551          *
1552          * Deprecated for public use, use Title::makeTitle() with fragment parameter,
1553          * or Title::createFragmentTarget().
1554          * Still in active use privately.
1555          *
1556          * @private
1557          * @param string $fragment Text
1558          */
1559         public function setFragment( $fragment ) {
1560                 $this->mFragment = strtr( substr( $fragment, 1 ), '_', ' ' );
1561         }
1562
1563         /**
1564          * Creates a new Title for a different fragment of the same page.
1565          *
1566          * @since 1.27
1567          * @param string $fragment
1568          * @return Title
1569          */
1570         public function createFragmentTarget( $fragment ) {
1571                 return self::makeTitle(
1572                         $this->getNamespace(),
1573                         $this->getText(),
1574                         $fragment,
1575                         $this->getInterwiki()
1576                 );
1577         }
1578
1579         /**
1580          * Prefix some arbitrary text with the namespace or interwiki prefix
1581          * of this object
1582          *
1583          * @param string $name The text
1584          * @return string The prefixed text
1585          */
1586         private function prefix( $name ) {
1587                 global $wgContLang;
1588
1589                 $p = '';
1590                 if ( $this->isExternal() ) {
1591                         $p = $this->mInterwiki . ':';
1592                 }
1593
1594                 if ( 0 != $this->mNamespace ) {
1595                         $nsText = $this->getNsText();
1596
1597                         if ( $nsText === false ) {
1598                                 // See T165149. Awkward, but better than erroneously linking to the main namespace.
1599                                 $nsText = $wgContLang->getNsText( NS_SPECIAL ) . ":Badtitle/NS{$this->mNamespace}";
1600                         }
1601
1602                         $p .= $nsText . ':';
1603                 }
1604                 return $p . $name;
1605         }
1606
1607         /**
1608          * Get the prefixed database key form
1609          *
1610          * @return string The prefixed title, with underscores and
1611          *  any interwiki and namespace prefixes
1612          */
1613         public function getPrefixedDBkey() {
1614                 $s = $this->prefix( $this->mDbkeyform );
1615                 $s = strtr( $s, ' ', '_' );
1616                 return $s;
1617         }
1618
1619         /**
1620          * Get the prefixed title with spaces.
1621          * This is the form usually used for display
1622          *
1623          * @return string The prefixed title, with spaces
1624          */
1625         public function getPrefixedText() {
1626                 if ( $this->mPrefixedText === null ) {
1627                         $s = $this->prefix( $this->mTextform );
1628                         $s = strtr( $s, '_', ' ' );
1629                         $this->mPrefixedText = $s;
1630                 }
1631                 return $this->mPrefixedText;
1632         }
1633
1634         /**
1635          * Return a string representation of this title
1636          *
1637          * @return string Representation of this title
1638          */
1639         public function __toString() {
1640                 return $this->getPrefixedText();
1641         }
1642
1643         /**
1644          * Get the prefixed title with spaces, plus any fragment
1645          * (part beginning with '#')
1646          *
1647          * @return string The prefixed title, with spaces and the fragment, including '#'
1648          */
1649         public function getFullText() {
1650                 $text = $this->getPrefixedText();
1651                 if ( $this->hasFragment() ) {
1652                         $text .= '#' . $this->getFragment();
1653                 }
1654                 return $text;
1655         }
1656
1657         /**
1658          * Get the root page name text without a namespace, i.e. the leftmost part before any slashes
1659          *
1660          * @par Example:
1661          * @code
1662          * Title::newFromText('User:Foo/Bar/Baz')->getRootText();
1663          * # returns: 'Foo'
1664          * @endcode
1665          *
1666          * @return string Root name
1667          * @since 1.20
1668          */
1669         public function getRootText() {
1670                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1671                         return $this->getText();
1672                 }
1673
1674                 return strtok( $this->getText(), '/' );
1675         }
1676
1677         /**
1678          * Get the root page name title, i.e. the leftmost part before any slashes
1679          *
1680          * @par Example:
1681          * @code
1682          * Title::newFromText('User:Foo/Bar/Baz')->getRootTitle();
1683          * # returns: Title{User:Foo}
1684          * @endcode
1685          *
1686          * @return Title Root title
1687          * @since 1.20
1688          */
1689         public function getRootTitle() {
1690                 return self::makeTitle( $this->getNamespace(), $this->getRootText() );
1691         }
1692
1693         /**
1694          * Get the base page name without a namespace, i.e. the part before the subpage name
1695          *
1696          * @par Example:
1697          * @code
1698          * Title::newFromText('User:Foo/Bar/Baz')->getBaseText();
1699          * # returns: 'Foo/Bar'
1700          * @endcode
1701          *
1702          * @return string Base name
1703          */
1704         public function getBaseText() {
1705                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1706                         return $this->getText();
1707                 }
1708
1709                 $parts = explode( '/', $this->getText() );
1710                 # Don't discard the real title if there's no subpage involved
1711                 if ( count( $parts ) > 1 ) {
1712                         unset( $parts[count( $parts ) - 1] );
1713                 }
1714                 return implode( '/', $parts );
1715         }
1716
1717         /**
1718          * Get the base page name title, i.e. the part before the subpage name
1719          *
1720          * @par Example:
1721          * @code
1722          * Title::newFromText('User:Foo/Bar/Baz')->getBaseTitle();
1723          * # returns: Title{User:Foo/Bar}
1724          * @endcode
1725          *
1726          * @return Title Base title
1727          * @since 1.20
1728          */
1729         public function getBaseTitle() {
1730                 return self::makeTitle( $this->getNamespace(), $this->getBaseText() );
1731         }
1732
1733         /**
1734          * Get the lowest-level subpage name, i.e. the rightmost part after any slashes
1735          *
1736          * @par Example:
1737          * @code
1738          * Title::newFromText('User:Foo/Bar/Baz')->getSubpageText();
1739          * # returns: "Baz"
1740          * @endcode
1741          *
1742          * @return string Subpage name
1743          */
1744         public function getSubpageText() {
1745                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1746                         return $this->mTextform;
1747                 }
1748                 $parts = explode( '/', $this->mTextform );
1749                 return $parts[count( $parts ) - 1];
1750         }
1751
1752         /**
1753          * Get the title for a subpage of the current page
1754          *
1755          * @par Example:
1756          * @code
1757          * Title::newFromText('User:Foo/Bar/Baz')->getSubpage("Asdf");
1758          * # returns: Title{User:Foo/Bar/Baz/Asdf}
1759          * @endcode
1760          *
1761          * @param string $text The subpage name to add to the title
1762          * @return Title Subpage title
1763          * @since 1.20
1764          */
1765         public function getSubpage( $text ) {
1766                 return self::makeTitleSafe( $this->getNamespace(), $this->getText() . '/' . $text );
1767         }
1768
1769         /**
1770          * Get a URL-encoded form of the subpage text
1771          *
1772          * @return string URL-encoded subpage name
1773          */
1774         public function getSubpageUrlForm() {
1775                 $text = $this->getSubpageText();
1776                 $text = wfUrlencode( strtr( $text, ' ', '_' ) );
1777                 return $text;
1778         }
1779
1780         /**
1781          * Get a URL-encoded title (not an actual URL) including interwiki
1782          *
1783          * @return string The URL-encoded form
1784          */
1785         public function getPrefixedURL() {
1786                 $s = $this->prefix( $this->mDbkeyform );
1787                 $s = wfUrlencode( strtr( $s, ' ', '_' ) );
1788                 return $s;
1789         }
1790
1791         /**
1792          * Helper to fix up the get{Canonical,Full,Link,Local,Internal}URL args
1793          * get{Canonical,Full,Link,Local,Internal}URL methods accepted an optional
1794          * second argument named variant. This was deprecated in favor
1795          * of passing an array of option with a "variant" key
1796          * Once $query2 is removed for good, this helper can be dropped
1797          * and the wfArrayToCgi moved to getLocalURL();
1798          *
1799          * @since 1.19 (r105919)
1800          * @param array|string $query
1801          * @param string|string[]|bool $query2
1802          * @return string
1803          */
1804         private static function fixUrlQueryArgs( $query, $query2 = false ) {
1805                 if ( $query2 !== false ) {
1806                         wfDeprecated( "Title::get{Canonical,Full,Link,Local,Internal}URL " .
1807                                 "method called with a second parameter is deprecated. Add your " .
1808                                 "parameter to an array passed as the first parameter.", "1.19" );
1809                 }
1810                 if ( is_array( $query ) ) {
1811                         $query = wfArrayToCgi( $query );
1812                 }
1813                 if ( $query2 ) {
1814                         if ( is_string( $query2 ) ) {
1815                                 // $query2 is a string, we will consider this to be
1816                                 // a deprecated $variant argument and add it to the query
1817                                 $query2 = wfArrayToCgi( [ 'variant' => $query2 ] );
1818                         } else {
1819                                 $query2 = wfArrayToCgi( $query2 );
1820                         }
1821                         // If we have $query content add a & to it first
1822                         if ( $query ) {
1823                                 $query .= '&';
1824                         }
1825                         // Now append the queries together
1826                         $query .= $query2;
1827                 }
1828                 return $query;
1829         }
1830
1831         /**
1832          * Get a real URL referring to this title, with interwiki link and
1833          * fragment
1834          *
1835          * @see self::getLocalURL for the arguments.
1836          * @see wfExpandUrl
1837          * @param string|string[] $query
1838          * @param string|string[]|bool $query2
1839          * @param string|int|null $proto Protocol type to use in URL
1840          * @return string The URL
1841          */
1842         public function getFullURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1843                 $query = self::fixUrlQueryArgs( $query, $query2 );
1844
1845                 # Hand off all the decisions on urls to getLocalURL
1846                 $url = $this->getLocalURL( $query );
1847
1848                 # Expand the url to make it a full url. Note that getLocalURL has the
1849                 # potential to output full urls for a variety of reasons, so we use
1850                 # wfExpandUrl instead of simply prepending $wgServer
1851                 $url = wfExpandUrl( $url, $proto );
1852
1853                 # Finally, add the fragment.
1854                 $url .= $this->getFragmentForURL();
1855                 // Avoid PHP 7.1 warning from passing $this by reference
1856                 $titleRef = $this;
1857                 Hooks::run( 'GetFullURL', [ &$titleRef, &$url, $query ] );
1858                 return $url;
1859         }
1860
1861         /**
1862          * Get a url appropriate for making redirects based on an untrusted url arg
1863          *
1864          * This is basically the same as getFullUrl(), but in the case of external
1865          * interwikis, we send the user to a landing page, to prevent possible
1866          * phishing attacks and the like.
1867          *
1868          * @note Uses current protocol by default, since technically relative urls
1869          *   aren't allowed in redirects per HTTP spec, so this is not suitable for
1870          *   places where the url gets cached, as might pollute between
1871          *   https and non-https users.
1872          * @see self::getLocalURL for the arguments.
1873          * @param array|string $query
1874          * @param string $proto Protocol type to use in URL
1875          * @return string A url suitable to use in an HTTP location header.
1876          */
1877         public function getFullUrlForRedirect( $query = '', $proto = PROTO_CURRENT ) {
1878                 $target = $this;
1879                 if ( $this->isExternal() ) {
1880                         $target = SpecialPage::getTitleFor(
1881                                 'GoToInterwiki',
1882                                 $this->getPrefixedDBkey()
1883                         );
1884                 }
1885                 return $target->getFullURL( $query, false, $proto );
1886         }
1887
1888         /**
1889          * Get a URL with no fragment or server name (relative URL) from a Title object.
1890          * If this page is generated with action=render, however,
1891          * $wgServer is prepended to make an absolute URL.
1892          *
1893          * @see self::getFullURL to always get an absolute URL.
1894          * @see self::getLinkURL to always get a URL that's the simplest URL that will be
1895          *  valid to link, locally, to the current Title.
1896          * @see self::newFromText to produce a Title object.
1897          *
1898          * @param string|string[] $query An optional query string,
1899          *   not used for interwiki links. Can be specified as an associative array as well,
1900          *   e.g., array( 'action' => 'edit' ) (keys and values will be URL-escaped).
1901          *   Some query patterns will trigger various shorturl path replacements.
1902          * @param string|string[]|bool $query2 An optional secondary query array. This one MUST
1903          *   be an array. If a string is passed it will be interpreted as a deprecated
1904          *   variant argument and urlencoded into a variant= argument.
1905          *   This second query argument will be added to the $query
1906          *   The second parameter is deprecated since 1.19. Pass it as a key,value
1907          *   pair in the first parameter array instead.
1908          *
1909          * @return string String of the URL.
1910          */
1911         public function getLocalURL( $query = '', $query2 = false ) {
1912                 global $wgArticlePath, $wgScript, $wgServer, $wgRequest;
1913
1914                 $query = self::fixUrlQueryArgs( $query, $query2 );
1915
1916                 $interwiki = self::getInterwikiLookup()->fetch( $this->mInterwiki );
1917                 if ( $interwiki ) {
1918                         $namespace = $this->getNsText();
1919                         if ( $namespace != '' ) {
1920                                 # Can this actually happen? Interwikis shouldn't be parsed.
1921                                 # Yes! It can in interwiki transclusion. But... it probably shouldn't.
1922                                 $namespace .= ':';
1923                         }
1924                         $url = $interwiki->getURL( $namespace . $this->getDBkey() );
1925                         $url = wfAppendQuery( $url, $query );
1926                 } else {
1927                         $dbkey = wfUrlencode( $this->getPrefixedDBkey() );
1928                         if ( $query == '' ) {
1929                                 $url = str_replace( '$1', $dbkey, $wgArticlePath );
1930                                 // Avoid PHP 7.1 warning from passing $this by reference
1931                                 $titleRef = $this;
1932                                 Hooks::run( 'GetLocalURL::Article', [ &$titleRef, &$url ] );
1933                         } else {
1934                                 global $wgVariantArticlePath, $wgActionPaths, $wgContLang;
1935                                 $url = false;
1936                                 $matches = [];
1937
1938                                 if ( !empty( $wgActionPaths )
1939                                         && preg_match( '/^(.*&|)action=([^&]*)(&(.*)|)$/', $query, $matches )
1940                                 ) {
1941                                         $action = urldecode( $matches[2] );
1942                                         if ( isset( $wgActionPaths[$action] ) ) {
1943                                                 $query = $matches[1];
1944                                                 if ( isset( $matches[4] ) ) {
1945                                                         $query .= $matches[4];
1946                                                 }
1947                                                 $url = str_replace( '$1', $dbkey, $wgActionPaths[$action] );
1948                                                 if ( $query != '' ) {
1949                                                         $url = wfAppendQuery( $url, $query );
1950                                                 }
1951                                         }
1952                                 }
1953
1954                                 if ( $url === false
1955                                         && $wgVariantArticlePath
1956                                         && preg_match( '/^variant=([^&]*)$/', $query, $matches )
1957                                         && $this->getPageLanguage()->equals( $wgContLang )
1958                                         && $this->getPageLanguage()->hasVariants()
1959                                 ) {
1960                                         $variant = urldecode( $matches[1] );
1961                                         if ( $this->getPageLanguage()->hasVariant( $variant ) ) {
1962                                                 // Only do the variant replacement if the given variant is a valid
1963                                                 // variant for the page's language.
1964                                                 $url = str_replace( '$2', urlencode( $variant ), $wgVariantArticlePath );
1965                                                 $url = str_replace( '$1', $dbkey, $url );
1966                                         }
1967                                 }
1968
1969                                 if ( $url === false ) {
1970                                         if ( $query == '-' ) {
1971                                                 $query = '';
1972                                         }
1973                                         $url = "{$wgScript}?title={$dbkey}&{$query}";
1974                                 }
1975                         }
1976                         // Avoid PHP 7.1 warning from passing $this by reference
1977                         $titleRef = $this;
1978                         Hooks::run( 'GetLocalURL::Internal', [ &$titleRef, &$url, $query ] );
1979
1980                         // @todo FIXME: This causes breakage in various places when we
1981                         // actually expected a local URL and end up with dupe prefixes.
1982                         if ( $wgRequest->getVal( 'action' ) == 'render' ) {
1983                                 $url = $wgServer . $url;
1984                         }
1985                 }
1986                 // Avoid PHP 7.1 warning from passing $this by reference
1987                 $titleRef = $this;
1988                 Hooks::run( 'GetLocalURL', [ &$titleRef, &$url, $query ] );
1989                 return $url;
1990         }
1991
1992         /**
1993          * Get a URL that's the simplest URL that will be valid to link, locally,
1994          * to the current Title.  It includes the fragment, but does not include
1995          * the server unless action=render is used (or the link is external).  If
1996          * there's a fragment but the prefixed text is empty, we just return a link
1997          * to the fragment.
1998          *
1999          * The result obviously should not be URL-escaped, but does need to be
2000          * HTML-escaped if it's being output in HTML.
2001          *
2002          * @param string|string[] $query
2003          * @param bool $query2
2004          * @param string|int|bool $proto A PROTO_* constant on how the URL should be expanded,
2005          *                               or false (default) for no expansion
2006          * @see self::getLocalURL for the arguments.
2007          * @return string The URL
2008          */
2009         public function getLinkURL( $query = '', $query2 = false, $proto = false ) {
2010                 if ( $this->isExternal() || $proto !== false ) {
2011                         $ret = $this->getFullURL( $query, $query2, $proto );
2012                 } elseif ( $this->getPrefixedText() === '' && $this->hasFragment() ) {
2013                         $ret = $this->getFragmentForURL();
2014                 } else {
2015                         $ret = $this->getLocalURL( $query, $query2 ) . $this->getFragmentForURL();
2016                 }
2017                 return $ret;
2018         }
2019
2020         /**
2021          * Get the URL form for an internal link.
2022          * - Used in various CDN-related code, in case we have a different
2023          * internal hostname for the server from the exposed one.
2024          *
2025          * This uses $wgInternalServer to qualify the path, or $wgServer
2026          * if $wgInternalServer is not set. If the server variable used is
2027          * protocol-relative, the URL will be expanded to http://
2028          *
2029          * @see self::getLocalURL for the arguments.
2030          * @param string $query
2031          * @param string|bool $query2
2032          * @return string The URL
2033          */
2034         public function getInternalURL( $query = '', $query2 = false ) {
2035                 global $wgInternalServer, $wgServer;
2036                 $query = self::fixUrlQueryArgs( $query, $query2 );
2037                 $server = $wgInternalServer !== false ? $wgInternalServer : $wgServer;
2038                 $url = wfExpandUrl( $server . $this->getLocalURL( $query ), PROTO_HTTP );
2039                 // Avoid PHP 7.1 warning from passing $this by reference
2040                 $titleRef = $this;
2041                 Hooks::run( 'GetInternalURL', [ &$titleRef, &$url, $query ] );
2042                 return $url;
2043         }
2044
2045         /**
2046          * Get the URL for a canonical link, for use in things like IRC and
2047          * e-mail notifications. Uses $wgCanonicalServer and the
2048          * GetCanonicalURL hook.
2049          *
2050          * NOTE: Unlike getInternalURL(), the canonical URL includes the fragment
2051          *
2052          * @see self::getLocalURL for the arguments.
2053          * @param string $query
2054          * @param string|bool $query2
2055          * @return string The URL
2056          * @since 1.18
2057          */
2058         public function getCanonicalURL( $query = '', $query2 = false ) {
2059                 $query = self::fixUrlQueryArgs( $query, $query2 );
2060                 $url = wfExpandUrl( $this->getLocalURL( $query ) . $this->getFragmentForURL(), PROTO_CANONICAL );
2061                 // Avoid PHP 7.1 warning from passing $this by reference
2062                 $titleRef = $this;
2063                 Hooks::run( 'GetCanonicalURL', [ &$titleRef, &$url, $query ] );
2064                 return $url;
2065         }
2066
2067         /**
2068          * Get the edit URL for this Title
2069          *
2070          * @return string The URL, or a null string if this is an interwiki link
2071          */
2072         public function getEditURL() {
2073                 if ( $this->isExternal() ) {
2074                         return '';
2075                 }
2076                 $s = $this->getLocalURL( 'action=edit' );
2077
2078                 return $s;
2079         }
2080
2081         /**
2082          * Can $user perform $action on this page?
2083          * This skips potentially expensive cascading permission checks
2084          * as well as avoids expensive error formatting
2085          *
2086          * Suitable for use for nonessential UI controls in common cases, but
2087          * _not_ for functional access control.
2088          *
2089          * May provide false positives, but should never provide a false negative.
2090          *
2091          * @param string $action Action that permission needs to be checked for
2092          * @param User $user User to check (since 1.19); $wgUser will be used if not provided.
2093          * @return bool
2094          */
2095         public function quickUserCan( $action, $user = null ) {
2096                 return $this->userCan( $action, $user, false );
2097         }
2098
2099         /**
2100          * Can $user perform $action on this page?
2101          *
2102          * @param string $action Action that permission needs to be checked for
2103          * @param User $user User to check (since 1.19); $wgUser will be used if not
2104          *   provided.
2105          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2106          * @return bool
2107          */
2108         public function userCan( $action, $user = null, $rigor = 'secure' ) {
2109                 if ( !$user instanceof User ) {
2110                         global $wgUser;
2111                         $user = $wgUser;
2112                 }
2113
2114                 return !count( $this->getUserPermissionsErrorsInternal( $action, $user, $rigor, true ) );
2115         }
2116
2117         /**
2118          * Can $user perform $action on this page?
2119          *
2120          * @todo FIXME: This *does not* check throttles (User::pingLimiter()).
2121          *
2122          * @param string $action Action that permission needs to be checked for
2123          * @param User $user User to check
2124          * @param string $rigor One of (quick,full,secure)
2125          *   - quick  : does cheap permission checks from replica DBs (usable for GUI creation)
2126          *   - full   : does cheap and expensive checks possibly from a replica DB
2127          *   - secure : does cheap and expensive checks, using the master as needed
2128          * @param array $ignoreErrors Array of Strings Set this to a list of message keys
2129          *   whose corresponding errors may be ignored.
2130          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
2131          */
2132         public function getUserPermissionsErrors(
2133                 $action, $user, $rigor = 'secure', $ignoreErrors = []
2134         ) {
2135                 $errors = $this->getUserPermissionsErrorsInternal( $action, $user, $rigor );
2136
2137                 // Remove the errors being ignored.
2138                 foreach ( $errors as $index => $error ) {
2139                         $errKey = is_array( $error ) ? $error[0] : $error;
2140
2141                         if ( in_array( $errKey, $ignoreErrors ) ) {
2142                                 unset( $errors[$index] );
2143                         }
2144                         if ( $errKey instanceof MessageSpecifier && in_array( $errKey->getKey(), $ignoreErrors ) ) {
2145                                 unset( $errors[$index] );
2146                         }
2147                 }
2148
2149                 return $errors;
2150         }
2151
2152         /**
2153          * Permissions checks that fail most often, and which are easiest to test.
2154          *
2155          * @param string $action The action to check
2156          * @param User $user User to check
2157          * @param array $errors List of current errors
2158          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2159          * @param bool $short Short circuit on first error
2160          *
2161          * @return array List of errors
2162          */
2163         private function checkQuickPermissions( $action, $user, $errors, $rigor, $short ) {
2164                 if ( !Hooks::run( 'TitleQuickPermissions',
2165                         [ $this, $user, $action, &$errors, ( $rigor !== 'quick' ), $short ] )
2166                 ) {
2167                         return $errors;
2168                 }
2169
2170                 if ( $action == 'create' ) {
2171                         if (
2172                                 ( $this->isTalkPage() && !$user->isAllowed( 'createtalk' ) ) ||
2173                                 ( !$this->isTalkPage() && !$user->isAllowed( 'createpage' ) )
2174                         ) {
2175                                 $errors[] = $user->isAnon() ? [ 'nocreatetext' ] : [ 'nocreate-loggedin' ];
2176                         }
2177                 } elseif ( $action == 'move' ) {
2178                         if ( !$user->isAllowed( 'move-rootuserpages' )
2179                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
2180                                 // Show user page-specific message only if the user can move other pages
2181                                 $errors[] = [ 'cant-move-user-page' ];
2182                         }
2183
2184                         // Check if user is allowed to move files if it's a file
2185                         if ( $this->mNamespace == NS_FILE && !$user->isAllowed( 'movefile' ) ) {
2186                                 $errors[] = [ 'movenotallowedfile' ];
2187                         }
2188
2189                         // Check if user is allowed to move category pages if it's a category page
2190                         if ( $this->mNamespace == NS_CATEGORY && !$user->isAllowed( 'move-categorypages' ) ) {
2191                                 $errors[] = [ 'cant-move-category-page' ];
2192                         }
2193
2194                         if ( !$user->isAllowed( 'move' ) ) {
2195                                 // User can't move anything
2196                                 $userCanMove = User::groupHasPermission( 'user', 'move' );
2197                                 $autoconfirmedCanMove = User::groupHasPermission( 'autoconfirmed', 'move' );
2198                                 if ( $user->isAnon() && ( $userCanMove || $autoconfirmedCanMove ) ) {
2199                                         // custom message if logged-in users without any special rights can move
2200                                         $errors[] = [ 'movenologintext' ];
2201                                 } else {
2202                                         $errors[] = [ 'movenotallowed' ];
2203                                 }
2204                         }
2205                 } elseif ( $action == 'move-target' ) {
2206                         if ( !$user->isAllowed( 'move' ) ) {
2207                                 // User can't move anything
2208                                 $errors[] = [ 'movenotallowed' ];
2209                         } elseif ( !$user->isAllowed( 'move-rootuserpages' )
2210                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
2211                                 // Show user page-specific message only if the user can move other pages
2212                                 $errors[] = [ 'cant-move-to-user-page' ];
2213                         } elseif ( !$user->isAllowed( 'move-categorypages' )
2214                                         && $this->mNamespace == NS_CATEGORY ) {
2215                                 // Show category page-specific message only if the user can move other pages
2216                                 $errors[] = [ 'cant-move-to-category-page' ];
2217                         }
2218                 } elseif ( !$user->isAllowed( $action ) ) {
2219                         $errors[] = $this->missingPermissionError( $action, $short );
2220                 }
2221
2222                 return $errors;
2223         }
2224
2225         /**
2226          * Add the resulting error code to the errors array
2227          *
2228          * @param array $errors List of current errors
2229          * @param array $result Result of errors
2230          *
2231          * @return array List of errors
2232          */
2233         private function resultToError( $errors, $result ) {
2234                 if ( is_array( $result ) && count( $result ) && !is_array( $result[0] ) ) {
2235                         // A single array representing an error
2236                         $errors[] = $result;
2237                 } elseif ( is_array( $result ) && is_array( $result[0] ) ) {
2238                         // A nested array representing multiple errors
2239                         $errors = array_merge( $errors, $result );
2240                 } elseif ( $result !== '' && is_string( $result ) ) {
2241                         // A string representing a message-id
2242                         $errors[] = [ $result ];
2243                 } elseif ( $result instanceof MessageSpecifier ) {
2244                         // A message specifier representing an error
2245                         $errors[] = [ $result ];
2246                 } elseif ( $result === false ) {
2247                         // a generic "We don't want them to do that"
2248                         $errors[] = [ 'badaccess-group0' ];
2249                 }
2250                 return $errors;
2251         }
2252
2253         /**
2254          * Check various permission hooks
2255          *
2256          * @param string $action The action to check
2257          * @param User $user User to check
2258          * @param array $errors List of current errors
2259          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2260          * @param bool $short Short circuit on first error
2261          *
2262          * @return array List of errors
2263          */
2264         private function checkPermissionHooks( $action, $user, $errors, $rigor, $short ) {
2265                 // Use getUserPermissionsErrors instead
2266                 $result = '';
2267                 // Avoid PHP 7.1 warning from passing $this by reference
2268                 $titleRef = $this;
2269                 if ( !Hooks::run( 'userCan', [ &$titleRef, &$user, $action, &$result ] ) ) {
2270                         return $result ? [] : [ [ 'badaccess-group0' ] ];
2271                 }
2272                 // Check getUserPermissionsErrors hook
2273                 // Avoid PHP 7.1 warning from passing $this by reference
2274                 $titleRef = $this;
2275                 if ( !Hooks::run( 'getUserPermissionsErrors', [ &$titleRef, &$user, $action, &$result ] ) ) {
2276                         $errors = $this->resultToError( $errors, $result );
2277                 }
2278                 // Check getUserPermissionsErrorsExpensive hook
2279                 if (
2280                         $rigor !== 'quick'
2281                         && !( $short && count( $errors ) > 0 )
2282                         && !Hooks::run( 'getUserPermissionsErrorsExpensive', [ &$titleRef, &$user, $action, &$result ] )
2283                 ) {
2284                         $errors = $this->resultToError( $errors, $result );
2285                 }
2286
2287                 return $errors;
2288         }
2289
2290         /**
2291          * Check permissions on special pages & namespaces
2292          *
2293          * @param string $action The action to check
2294          * @param User $user User to check
2295          * @param array $errors List of current errors
2296          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2297          * @param bool $short Short circuit on first error
2298          *
2299          * @return array List of errors
2300          */
2301         private function checkSpecialsAndNSPermissions( $action, $user, $errors, $rigor, $short ) {
2302                 # Only 'createaccount' can be performed on special pages,
2303                 # which don't actually exist in the DB.
2304                 if ( $this->isSpecialPage() && $action !== 'createaccount' ) {
2305                         $errors[] = [ 'ns-specialprotected' ];
2306                 }
2307
2308                 # Check $wgNamespaceProtection for restricted namespaces
2309                 if ( $this->isNamespaceProtected( $user ) ) {
2310                         $ns = $this->mNamespace == NS_MAIN ?
2311                                 wfMessage( 'nstab-main' )->text() : $this->getNsText();
2312                         $errors[] = $this->mNamespace == NS_MEDIAWIKI ?
2313                                 [ 'protectedinterface', $action ] : [ 'namespaceprotected', $ns, $action ];
2314                 }
2315
2316                 return $errors;
2317         }
2318
2319         /**
2320          * Check CSS/JSON/JS sub-page permissions
2321          *
2322          * @param string $action The action to check
2323          * @param User $user User to check
2324          * @param array $errors List of current errors
2325          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2326          * @param bool $short Short circuit on first error
2327          *
2328          * @return array List of errors
2329          */
2330         private function checkUserConfigPermissions( $action, $user, $errors, $rigor, $short ) {
2331                 # Protect css/json/js subpages of user pages
2332                 # XXX: this might be better using restrictions
2333
2334                 if ( $action != 'patrol' ) {
2335                         if ( preg_match( '/^' . preg_quote( $user->getName(), '/' ) . '\//', $this->mTextform ) ) {
2336                                 if (
2337                                         $this->isUserCssConfigPage()
2338                                         && !$user->isAllowedAny( 'editmyusercss', 'editusercss' )
2339                                 ) {
2340                                         $errors[] = [ 'mycustomcssprotected', $action ];
2341                                 } elseif (
2342                                         $this->isUserJsonConfigPage()
2343                                         && !$user->isAllowedAny( 'editmyuserjson', 'edituserjson' )
2344                                 ) {
2345                                         $errors[] = [ 'mycustomjsonprotected', $action ];
2346                                 } elseif (
2347                                         $this->isUserJsConfigPage()
2348                                         && !$user->isAllowedAny( 'editmyuserjs', 'edituserjs' )
2349                                 ) {
2350                                         $errors[] = [ 'mycustomjsprotected', $action ];
2351                                 }
2352                         } else {
2353                                 if (
2354                                         $this->isUserCssConfigPage()
2355                                         && !$user->isAllowed( 'editusercss' )
2356                                 ) {
2357                                         $errors[] = [ 'customcssprotected', $action ];
2358                                 } elseif (
2359                                         $this->isUserJsonConfigPage()
2360                                         && !$user->isAllowed( 'edituserjson' )
2361                                 ) {
2362                                         $errors[] = [ 'customjsonprotected', $action ];
2363                                 } elseif (
2364                                         $this->isUserJsConfigPage()
2365                                         && !$user->isAllowed( 'edituserjs' )
2366                                 ) {
2367                                         $errors[] = [ 'customjsprotected', $action ];
2368                                 }
2369                         }
2370                 }
2371
2372                 return $errors;
2373         }
2374
2375         /**
2376          * Check against page_restrictions table requirements on this
2377          * page. The user must possess all required rights for this
2378          * action.
2379          *
2380          * @param string $action The action to check
2381          * @param User $user User to check
2382          * @param array $errors List of current errors
2383          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2384          * @param bool $short Short circuit on first error
2385          *
2386          * @return array List of errors
2387          */
2388         private function checkPageRestrictions( $action, $user, $errors, $rigor, $short ) {
2389                 foreach ( $this->getRestrictions( $action ) as $right ) {
2390                         // Backwards compatibility, rewrite sysop -> editprotected
2391                         if ( $right == 'sysop' ) {
2392                                 $right = 'editprotected';
2393                         }
2394                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2395                         if ( $right == 'autoconfirmed' ) {
2396                                 $right = 'editsemiprotected';
2397                         }
2398                         if ( $right == '' ) {
2399                                 continue;
2400                         }
2401                         if ( !$user->isAllowed( $right ) ) {
2402                                 $errors[] = [ 'protectedpagetext', $right, $action ];
2403                         } elseif ( $this->mCascadeRestriction && !$user->isAllowed( 'protect' ) ) {
2404                                 $errors[] = [ 'protectedpagetext', 'protect', $action ];
2405                         }
2406                 }
2407
2408                 return $errors;
2409         }
2410
2411         /**
2412          * Check restrictions on cascading pages.
2413          *
2414          * @param string $action The action to check
2415          * @param User $user User to check
2416          * @param array $errors List of current errors
2417          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2418          * @param bool $short Short circuit on first error
2419          *
2420          * @return array List of errors
2421          */
2422         private function checkCascadingSourcesRestrictions( $action, $user, $errors, $rigor, $short ) {
2423                 if ( $rigor !== 'quick' && !$this->isUserConfigPage() ) {
2424                         # We /could/ use the protection level on the source page, but it's
2425                         # fairly ugly as we have to establish a precedence hierarchy for pages
2426                         # included by multiple cascade-protected pages. So just restrict
2427                         # it to people with 'protect' permission, as they could remove the
2428                         # protection anyway.
2429                         list( $cascadingSources, $restrictions ) = $this->getCascadeProtectionSources();
2430                         # Cascading protection depends on more than this page...
2431                         # Several cascading protected pages may include this page...
2432                         # Check each cascading level
2433                         # This is only for protection restrictions, not for all actions
2434                         if ( isset( $restrictions[$action] ) ) {
2435                                 foreach ( $restrictions[$action] as $right ) {
2436                                         // Backwards compatibility, rewrite sysop -> editprotected
2437                                         if ( $right == 'sysop' ) {
2438                                                 $right = 'editprotected';
2439                                         }
2440                                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2441                                         if ( $right == 'autoconfirmed' ) {
2442                                                 $right = 'editsemiprotected';
2443                                         }
2444                                         if ( $right != '' && !$user->isAllowedAll( 'protect', $right ) ) {
2445                                                 $pages = '';
2446                                                 foreach ( $cascadingSources as $page ) {
2447                                                         $pages .= '* [[:' . $page->getPrefixedText() . "]]\n";
2448                                                 }
2449                                                 $errors[] = [ 'cascadeprotected', count( $cascadingSources ), $pages, $action ];
2450                                         }
2451                                 }
2452                         }
2453                 }
2454
2455                 return $errors;
2456         }
2457
2458         /**
2459          * Check action permissions not already checked in checkQuickPermissions
2460          *
2461          * @param string $action The action to check
2462          * @param User $user User to check
2463          * @param array $errors List of current errors
2464          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2465          * @param bool $short Short circuit on first error
2466          *
2467          * @return array List of errors
2468          */
2469         private function checkActionPermissions( $action, $user, $errors, $rigor, $short ) {
2470                 global $wgDeleteRevisionsLimit, $wgLang;
2471
2472                 if ( $action == 'protect' ) {
2473                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit', $user, $rigor, true ) ) ) {
2474                                 // If they can't edit, they shouldn't protect.
2475                                 $errors[] = [ 'protect-cantedit' ];
2476                         }
2477                 } elseif ( $action == 'create' ) {
2478                         $title_protection = $this->getTitleProtection();
2479                         if ( $title_protection ) {
2480                                 if ( $title_protection['permission'] == ''
2481                                         || !$user->isAllowed( $title_protection['permission'] )
2482                                 ) {
2483                                         $errors[] = [
2484                                                 'titleprotected',
2485                                                 User::whoIs( $title_protection['user'] ),
2486                                                 $title_protection['reason']
2487                                         ];
2488                                 }
2489                         }
2490                 } elseif ( $action == 'move' ) {
2491                         // Check for immobile pages
2492                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2493                                 // Specific message for this case
2494                                 $errors[] = [ 'immobile-source-namespace', $this->getNsText() ];
2495                         } elseif ( !$this->isMovable() ) {
2496                                 // Less specific message for rarer cases
2497                                 $errors[] = [ 'immobile-source-page' ];
2498                         }
2499                 } elseif ( $action == 'move-target' ) {
2500                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2501                                 $errors[] = [ 'immobile-target-namespace', $this->getNsText() ];
2502                         } elseif ( !$this->isMovable() ) {
2503                                 $errors[] = [ 'immobile-target-page' ];
2504                         }
2505                 } elseif ( $action == 'delete' ) {
2506                         $tempErrors = $this->checkPageRestrictions( 'edit', $user, [], $rigor, true );
2507                         if ( !$tempErrors ) {
2508                                 $tempErrors = $this->checkCascadingSourcesRestrictions( 'edit',
2509                                         $user, $tempErrors, $rigor, true );
2510                         }
2511                         if ( $tempErrors ) {
2512                                 // If protection keeps them from editing, they shouldn't be able to delete.
2513                                 $errors[] = [ 'deleteprotected' ];
2514                         }
2515                         if ( $rigor !== 'quick' && $wgDeleteRevisionsLimit
2516                                 && !$this->userCan( 'bigdelete', $user ) && $this->isBigDeletion()
2517                         ) {
2518                                 $errors[] = [ 'delete-toobig', $wgLang->formatNum( $wgDeleteRevisionsLimit ) ];
2519                         }
2520                 } elseif ( $action === 'undelete' ) {
2521                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit', $user, $rigor, true ) ) ) {
2522                                 // Undeleting implies editing
2523                                 $errors[] = [ 'undelete-cantedit' ];
2524                         }
2525                         if ( !$this->exists()
2526                                 && count( $this->getUserPermissionsErrorsInternal( 'create', $user, $rigor, true ) )
2527                         ) {
2528                                 // Undeleting where nothing currently exists implies creating
2529                                 $errors[] = [ 'undelete-cantcreate' ];
2530                         }
2531                 }
2532                 return $errors;
2533         }
2534
2535         /**
2536          * Check that the user isn't blocked from editing.
2537          *
2538          * @param string $action The action to check
2539          * @param User $user User to check
2540          * @param array $errors List of current errors
2541          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2542          * @param bool $short Short circuit on first error
2543          *
2544          * @return array List of errors
2545          */
2546         private function checkUserBlock( $action, $user, $errors, $rigor, $short ) {
2547                 global $wgEmailConfirmToEdit, $wgBlockDisablesLogin;
2548                 // Account creation blocks handled at userlogin.
2549                 // Unblocking handled in SpecialUnblock
2550                 if ( $rigor === 'quick' || in_array( $action, [ 'createaccount', 'unblock' ] ) ) {
2551                         return $errors;
2552                 }
2553
2554                 // Optimize for a very common case
2555                 if ( $action === 'read' && !$wgBlockDisablesLogin ) {
2556                         return $errors;
2557                 }
2558
2559                 if ( $wgEmailConfirmToEdit && !$user->isEmailConfirmed() ) {
2560                         $errors[] = [ 'confirmedittext' ];
2561                 }
2562
2563                 $useSlave = ( $rigor !== 'secure' );
2564                 if ( ( $action == 'edit' || $action == 'create' )
2565                         && !$user->isBlockedFrom( $this, $useSlave )
2566                 ) {
2567                         // Don't block the user from editing their own talk page unless they've been
2568                         // explicitly blocked from that too.
2569                 } elseif ( $user->isBlocked() && $user->getBlock()->prevents( $action ) !== false ) {
2570                         // @todo FIXME: Pass the relevant context into this function.
2571                         $errors[] = $user->getBlock()->getPermissionsError( RequestContext::getMain() );
2572                 }
2573
2574                 return $errors;
2575         }
2576
2577         /**
2578          * Check that the user is allowed to read this page.
2579          *
2580          * @param string $action The action to check
2581          * @param User $user User to check
2582          * @param array $errors List of current errors
2583          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2584          * @param bool $short Short circuit on first error
2585          *
2586          * @return array List of errors
2587          */
2588         private function checkReadPermissions( $action, $user, $errors, $rigor, $short ) {
2589                 global $wgWhitelistRead, $wgWhitelistReadRegexp;
2590
2591                 $whitelisted = false;
2592                 if ( User::isEveryoneAllowed( 'read' ) ) {
2593                         # Shortcut for public wikis, allows skipping quite a bit of code
2594                         $whitelisted = true;
2595                 } elseif ( $user->isAllowed( 'read' ) ) {
2596                         # If the user is allowed to read pages, he is allowed to read all pages
2597                         $whitelisted = true;
2598                 } elseif ( $this->isSpecial( 'Userlogin' )
2599                         || $this->isSpecial( 'PasswordReset' )
2600                         || $this->isSpecial( 'Userlogout' )
2601                 ) {
2602                         # Always grant access to the login page.
2603                         # Even anons need to be able to log in.
2604                         $whitelisted = true;
2605                 } elseif ( is_array( $wgWhitelistRead ) && count( $wgWhitelistRead ) ) {
2606                         # Time to check the whitelist
2607                         # Only do these checks is there's something to check against
2608                         $name = $this->getPrefixedText();
2609                         $dbName = $this->getPrefixedDBkey();
2610
2611                         // Check for explicit whitelisting with and without underscores
2612                         if ( in_array( $name, $wgWhitelistRead, true ) || in_array( $dbName, $wgWhitelistRead, true ) ) {
2613                                 $whitelisted = true;
2614                         } elseif ( $this->getNamespace() == NS_MAIN ) {
2615                                 # Old settings might have the title prefixed with
2616                                 # a colon for main-namespace pages
2617                                 if ( in_array( ':' . $name, $wgWhitelistRead ) ) {
2618                                         $whitelisted = true;
2619                                 }
2620                         } elseif ( $this->isSpecialPage() ) {
2621                                 # If it's a special page, ditch the subpage bit and check again
2622                                 $name = $this->getDBkey();
2623                                 list( $name, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $name );
2624                                 if ( $name ) {
2625                                         $pure = SpecialPage::getTitleFor( $name )->getPrefixedText();
2626                                         if ( in_array( $pure, $wgWhitelistRead, true ) ) {
2627                                                 $whitelisted = true;
2628                                         }
2629                                 }
2630                         }
2631                 }
2632
2633                 if ( !$whitelisted && is_array( $wgWhitelistReadRegexp ) && !empty( $wgWhitelistReadRegexp ) ) {
2634                         $name = $this->getPrefixedText();
2635                         // Check for regex whitelisting
2636                         foreach ( $wgWhitelistReadRegexp as $listItem ) {
2637                                 if ( preg_match( $listItem, $name ) ) {
2638                                         $whitelisted = true;
2639                                         break;
2640                                 }
2641                         }
2642                 }
2643
2644                 if ( !$whitelisted ) {
2645                         # If the title is not whitelisted, give extensions a chance to do so...
2646                         Hooks::run( 'TitleReadWhitelist', [ $this, $user, &$whitelisted ] );
2647                         if ( !$whitelisted ) {
2648                                 $errors[] = $this->missingPermissionError( $action, $short );
2649                         }
2650                 }
2651
2652                 return $errors;
2653         }
2654
2655         /**
2656          * Get a description array when the user doesn't have the right to perform
2657          * $action (i.e. when User::isAllowed() returns false)
2658          *
2659          * @param string $action The action to check
2660          * @param bool $short Short circuit on first error
2661          * @return array Array containing an error message key and any parameters
2662          */
2663         private function missingPermissionError( $action, $short ) {
2664                 // We avoid expensive display logic for quickUserCan's and such
2665                 if ( $short ) {
2666                         return [ 'badaccess-group0' ];
2667                 }
2668
2669                 return User::newFatalPermissionDeniedStatus( $action )->getErrorsArray()[0];
2670         }
2671
2672         /**
2673          * Can $user perform $action on this page? This is an internal function,
2674          * with multiple levels of checks depending on performance needs; see $rigor below.
2675          * It does not check wfReadOnly().
2676          *
2677          * @param string $action Action that permission needs to be checked for
2678          * @param User $user User to check
2679          * @param string $rigor One of (quick,full,secure)
2680          *   - quick  : does cheap permission checks from replica DBs (usable for GUI creation)
2681          *   - full   : does cheap and expensive checks possibly from a replica DB
2682          *   - secure : does cheap and expensive checks, using the master as needed
2683          * @param bool $short Set this to true to stop after the first permission error.
2684          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
2685          */
2686         protected function getUserPermissionsErrorsInternal(
2687                 $action, $user, $rigor = 'secure', $short = false
2688         ) {
2689                 if ( $rigor === true ) {
2690                         $rigor = 'secure'; // b/c
2691                 } elseif ( $rigor === false ) {
2692                         $rigor = 'quick'; // b/c
2693                 } elseif ( !in_array( $rigor, [ 'quick', 'full', 'secure' ] ) ) {
2694                         throw new Exception( "Invalid rigor parameter '$rigor'." );
2695                 }
2696
2697                 # Read has special handling
2698                 if ( $action == 'read' ) {
2699                         $checks = [
2700                                 'checkPermissionHooks',
2701                                 'checkReadPermissions',
2702                                 'checkUserBlock', // for wgBlockDisablesLogin
2703                         ];
2704                 # Don't call checkSpecialsAndNSPermissions or checkUserConfigPermissions
2705                 # here as it will lead to duplicate error messages. This is okay to do
2706                 # since anywhere that checks for create will also check for edit, and
2707                 # those checks are called for edit.
2708                 } elseif ( $action == 'create' ) {
2709                         $checks = [
2710                                 'checkQuickPermissions',
2711                                 'checkPermissionHooks',
2712                                 'checkPageRestrictions',
2713                                 'checkCascadingSourcesRestrictions',
2714                                 'checkActionPermissions',
2715                                 'checkUserBlock'
2716                         ];
2717                 } else {
2718                         $checks = [
2719                                 'checkQuickPermissions',
2720                                 'checkPermissionHooks',
2721                                 'checkSpecialsAndNSPermissions',
2722                                 'checkUserConfigPermissions',
2723                                 'checkPageRestrictions',
2724                                 'checkCascadingSourcesRestrictions',
2725                                 'checkActionPermissions',
2726                                 'checkUserBlock'
2727                         ];
2728                 }
2729
2730                 $errors = [];
2731                 while ( count( $checks ) > 0 &&
2732                                 !( $short && count( $errors ) > 0 ) ) {
2733                         $method = array_shift( $checks );
2734                         $errors = $this->$method( $action, $user, $errors, $rigor, $short );
2735                 }
2736
2737                 return $errors;
2738         }
2739
2740         /**
2741          * Get a filtered list of all restriction types supported by this wiki.
2742          * @param bool $exists True to get all restriction types that apply to
2743          * titles that do exist, False for all restriction types that apply to
2744          * titles that do not exist
2745          * @return array
2746          */
2747         public static function getFilteredRestrictionTypes( $exists = true ) {
2748                 global $wgRestrictionTypes;
2749                 $types = $wgRestrictionTypes;
2750                 if ( $exists ) {
2751                         # Remove the create restriction for existing titles
2752                         $types = array_diff( $types, [ 'create' ] );
2753                 } else {
2754                         # Only the create and upload restrictions apply to non-existing titles
2755                         $types = array_intersect( $types, [ 'create', 'upload' ] );
2756                 }
2757                 return $types;
2758         }
2759
2760         /**
2761          * Returns restriction types for the current Title
2762          *
2763          * @return array Applicable restriction types
2764          */
2765         public function getRestrictionTypes() {
2766                 if ( $this->isSpecialPage() ) {
2767                         return [];
2768                 }
2769
2770                 $types = self::getFilteredRestrictionTypes( $this->exists() );
2771
2772                 if ( $this->getNamespace() != NS_FILE ) {
2773                         # Remove the upload restriction for non-file titles
2774                         $types = array_diff( $types, [ 'upload' ] );
2775                 }
2776
2777                 Hooks::run( 'TitleGetRestrictionTypes', [ $this, &$types ] );
2778
2779                 wfDebug( __METHOD__ . ': applicable restrictions to [[' .
2780                         $this->getPrefixedText() . ']] are {' . implode( ',', $types ) . "}\n" );
2781
2782                 return $types;
2783         }
2784
2785         /**
2786          * Is this title subject to title protection?
2787          * Title protection is the one applied against creation of such title.
2788          *
2789          * @return array|bool An associative array representing any existent title
2790          *   protection, or false if there's none.
2791          */
2792         public function getTitleProtection() {
2793                 $protection = $this->getTitleProtectionInternal();
2794                 if ( $protection ) {
2795                         if ( $protection['permission'] == 'sysop' ) {
2796                                 $protection['permission'] = 'editprotected'; // B/C
2797                         }
2798                         if ( $protection['permission'] == 'autoconfirmed' ) {
2799                                 $protection['permission'] = 'editsemiprotected'; // B/C
2800                         }
2801                 }
2802                 return $protection;
2803         }
2804
2805         /**
2806          * Fetch title protection settings
2807          *
2808          * To work correctly, $this->loadRestrictions() needs to have access to the
2809          * actual protections in the database without munging 'sysop' =>
2810          * 'editprotected' and 'autoconfirmed' => 'editsemiprotected'. Other
2811          * callers probably want $this->getTitleProtection() instead.
2812          *
2813          * @return array|bool
2814          */
2815         protected function getTitleProtectionInternal() {
2816                 // Can't protect pages in special namespaces
2817                 if ( $this->getNamespace() < 0 ) {
2818                         return false;
2819                 }
2820
2821                 // Can't protect pages that exist.
2822                 if ( $this->exists() ) {
2823                         return false;
2824                 }
2825
2826                 if ( $this->mTitleProtection === null ) {
2827                         $dbr = wfGetDB( DB_REPLICA );
2828                         $commentStore = CommentStore::getStore();
2829                         $commentQuery = $commentStore->getJoin( 'pt_reason' );
2830                         $res = $dbr->select(
2831                                 [ 'protected_titles' ] + $commentQuery['tables'],
2832                                 [
2833                                         'user' => 'pt_user',
2834                                         'expiry' => 'pt_expiry',
2835                                         'permission' => 'pt_create_perm'
2836                                 ] + $commentQuery['fields'],
2837                                 [ 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ],
2838                                 __METHOD__,
2839                                 [],
2840                                 $commentQuery['joins']
2841                         );
2842
2843                         // fetchRow returns false if there are no rows.
2844                         $row = $dbr->fetchRow( $res );
2845                         if ( $row ) {
2846                                 $this->mTitleProtection = [
2847                                         'user' => $row['user'],
2848                                         'expiry' => $dbr->decodeExpiry( $row['expiry'] ),
2849                                         'permission' => $row['permission'],
2850                                         'reason' => $commentStore->getComment( 'pt_reason', $row )->text,
2851                                 ];
2852                         } else {
2853                                 $this->mTitleProtection = false;
2854                         }
2855                 }
2856                 return $this->mTitleProtection;
2857         }
2858
2859         /**
2860          * Remove any title protection due to page existing
2861          */
2862         public function deleteTitleProtection() {
2863                 $dbw = wfGetDB( DB_MASTER );
2864
2865                 $dbw->delete(
2866                         'protected_titles',
2867                         [ 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ],
2868                         __METHOD__
2869                 );
2870                 $this->mTitleProtection = false;
2871         }
2872
2873         /**
2874          * Is this page "semi-protected" - the *only* protection levels are listed
2875          * in $wgSemiprotectedRestrictionLevels?
2876          *
2877          * @param string $action Action to check (default: edit)
2878          * @return bool
2879          */
2880         public function isSemiProtected( $action = 'edit' ) {
2881                 global $wgSemiprotectedRestrictionLevels;
2882
2883                 $restrictions = $this->getRestrictions( $action );
2884                 $semi = $wgSemiprotectedRestrictionLevels;
2885                 if ( !$restrictions || !$semi ) {
2886                         // Not protected, or all protection is full protection
2887                         return false;
2888                 }
2889
2890                 // Remap autoconfirmed to editsemiprotected for BC
2891                 foreach ( array_keys( $semi, 'autoconfirmed' ) as $key ) {
2892                         $semi[$key] = 'editsemiprotected';
2893                 }
2894                 foreach ( array_keys( $restrictions, 'autoconfirmed' ) as $key ) {
2895                         $restrictions[$key] = 'editsemiprotected';
2896                 }
2897
2898                 return !array_diff( $restrictions, $semi );
2899         }
2900
2901         /**
2902          * Does the title correspond to a protected article?
2903          *
2904          * @param string $action The action the page is protected from,
2905          * by default checks all actions.
2906          * @return bool
2907          */
2908         public function isProtected( $action = '' ) {
2909                 global $wgRestrictionLevels;
2910
2911                 $restrictionTypes = $this->getRestrictionTypes();
2912
2913                 # Special pages have inherent protection
2914                 if ( $this->isSpecialPage() ) {
2915                         return true;
2916                 }
2917
2918                 # Check regular protection levels
2919                 foreach ( $restrictionTypes as $type ) {
2920                         if ( $action == $type || $action == '' ) {
2921                                 $r = $this->getRestrictions( $type );
2922                                 foreach ( $wgRestrictionLevels as $level ) {
2923                                         if ( in_array( $level, $r ) && $level != '' ) {
2924                                                 return true;
2925                                         }
2926                                 }
2927                         }
2928                 }
2929
2930                 return false;
2931         }
2932
2933         /**
2934          * Determines if $user is unable to edit this page because it has been protected
2935          * by $wgNamespaceProtection.
2936          *
2937          * @param User $user User object to check permissions
2938          * @return bool
2939          */
2940         public function isNamespaceProtected( User $user ) {
2941                 global $wgNamespaceProtection;
2942
2943                 if ( isset( $wgNamespaceProtection[$this->mNamespace] ) ) {
2944                         foreach ( (array)$wgNamespaceProtection[$this->mNamespace] as $right ) {
2945                                 if ( $right != '' && !$user->isAllowed( $right ) ) {
2946                                         return true;
2947                                 }
2948                         }
2949                 }
2950                 return false;
2951         }
2952
2953         /**
2954          * Cascading protection: Return true if cascading restrictions apply to this page, false if not.
2955          *
2956          * @return bool If the page is subject to cascading restrictions.
2957          */
2958         public function isCascadeProtected() {
2959                 list( $sources, /* $restrictions */ ) = $this->getCascadeProtectionSources( false );
2960                 return ( $sources > 0 );
2961         }
2962
2963         /**
2964          * Determines whether cascading protection sources have already been loaded from
2965          * the database.
2966          *
2967          * @param bool $getPages True to check if the pages are loaded, or false to check
2968          * if the status is loaded.
2969          * @return bool Whether or not the specified information has been loaded
2970          * @since 1.23
2971          */
2972         public function areCascadeProtectionSourcesLoaded( $getPages = true ) {
2973                 return $getPages ? $this->mCascadeSources !== null : $this->mHasCascadingRestrictions !== null;
2974         }
2975
2976         /**
2977          * Cascading protection: Get the source of any cascading restrictions on this page.
2978          *
2979          * @param bool $getPages Whether or not to retrieve the actual pages
2980          *        that the restrictions have come from and the actual restrictions
2981          *        themselves.
2982          * @return array Two elements: First is an array of Title objects of the
2983          *        pages from which cascading restrictions have come, false for
2984          *        none, or true if such restrictions exist but $getPages was not
2985          *        set. Second is an array like that returned by
2986          *        Title::getAllRestrictions(), or an empty array if $getPages is
2987          *        false.
2988          */
2989         public function getCascadeProtectionSources( $getPages = true ) {
2990                 $pagerestrictions = [];
2991
2992                 if ( $this->mCascadeSources !== null && $getPages ) {
2993                         return [ $this->mCascadeSources, $this->mCascadingRestrictions ];
2994                 } elseif ( $this->mHasCascadingRestrictions !== null && !$getPages ) {
2995                         return [ $this->mHasCascadingRestrictions, $pagerestrictions ];
2996                 }
2997
2998                 $dbr = wfGetDB( DB_REPLICA );
2999
3000                 if ( $this->getNamespace() == NS_FILE ) {
3001                         $tables = [ 'imagelinks', 'page_restrictions' ];
3002                         $where_clauses = [
3003                                 'il_to' => $this->getDBkey(),
3004                                 'il_from=pr_page',
3005                                 'pr_cascade' => 1
3006                         ];
3007                 } else {
3008                         $tables = [ 'templatelinks', 'page_restrictions' ];
3009                         $where_clauses = [
3010                                 'tl_namespace' => $this->getNamespace(),
3011                                 'tl_title' => $this->getDBkey(),
3012                                 'tl_from=pr_page',
3013                                 'pr_cascade' => 1
3014                         ];
3015                 }
3016
3017                 if ( $getPages ) {
3018                         $cols = [ 'pr_page', 'page_namespace', 'page_title',
3019                                 'pr_expiry', 'pr_type', 'pr_level' ];
3020                         $where_clauses[] = 'page_id=pr_page';
3021                         $tables[] = 'page';
3022                 } else {
3023                         $cols = [ 'pr_expiry' ];
3024                 }
3025
3026                 $res = $dbr->select( $tables, $cols, $where_clauses, __METHOD__ );
3027
3028                 $sources = $getPages ? [] : false;
3029                 $now = wfTimestampNow();
3030
3031                 foreach ( $res as $row ) {
3032                         $expiry = $dbr->decodeExpiry( $row->pr_expiry );
3033                         if ( $expiry > $now ) {
3034                                 if ( $getPages ) {
3035                                         $page_id = $row->pr_page;
3036                                         $page_ns = $row->page_namespace;
3037                                         $page_title = $row->page_title;
3038                                         $sources[$page_id] = self::makeTitle( $page_ns, $page_title );
3039                                         # Add groups needed for each restriction type if its not already there
3040                                         # Make sure this restriction type still exists
3041
3042                                         if ( !isset( $pagerestrictions[$row->pr_type] ) ) {
3043                                                 $pagerestrictions[$row->pr_type] = [];
3044                                         }
3045
3046                                         if (
3047                                                 isset( $pagerestrictions[$row->pr_type] )
3048                                                 && !in_array( $row->pr_level, $pagerestrictions[$row->pr_type] )
3049                                         ) {
3050                                                 $pagerestrictions[$row->pr_type][] = $row->pr_level;
3051                                         }
3052                                 } else {
3053                                         $sources = true;
3054                                 }
3055                         }
3056                 }
3057
3058                 if ( $getPages ) {
3059                         $this->mCascadeSources = $sources;
3060                         $this->mCascadingRestrictions = $pagerestrictions;
3061                 } else {
3062                         $this->mHasCascadingRestrictions = $sources;
3063                 }
3064
3065                 return [ $sources, $pagerestrictions ];
3066         }
3067
3068         /**
3069          * Accessor for mRestrictionsLoaded
3070          *
3071          * @return bool Whether or not the page's restrictions have already been
3072          * loaded from the database
3073          * @since 1.23
3074          */
3075         public function areRestrictionsLoaded() {
3076                 return $this->mRestrictionsLoaded;
3077         }
3078
3079         /**
3080          * Accessor/initialisation for mRestrictions
3081          *
3082          * @param string $action Action that permission needs to be checked for
3083          * @return array Restriction levels needed to take the action. All levels are
3084          *     required. Note that restriction levels are normally user rights, but 'sysop'
3085          *     and 'autoconfirmed' are also allowed for backwards compatibility. These should
3086          *     be mapped to 'editprotected' and 'editsemiprotected' respectively.
3087          */
3088         public function getRestrictions( $action ) {
3089                 if ( !$this->mRestrictionsLoaded ) {
3090                         $this->loadRestrictions();
3091                 }
3092                 return isset( $this->mRestrictions[$action] )
3093                                 ? $this->mRestrictions[$action]
3094                                 : [];
3095         }
3096
3097         /**
3098          * Accessor/initialisation for mRestrictions
3099          *
3100          * @return array Keys are actions, values are arrays as returned by
3101          *     Title::getRestrictions()
3102          * @since 1.23
3103          */
3104         public function getAllRestrictions() {
3105                 if ( !$this->mRestrictionsLoaded ) {
3106                         $this->loadRestrictions();
3107                 }
3108                 return $this->mRestrictions;
3109         }
3110
3111         /**
3112          * Get the expiry time for the restriction against a given action
3113          *
3114          * @param string $action
3115          * @return string|bool 14-char timestamp, or 'infinity' if the page is protected forever
3116          *     or not protected at all, or false if the action is not recognised.
3117          */
3118         public function getRestrictionExpiry( $action ) {
3119                 if ( !$this->mRestrictionsLoaded ) {
3120                         $this->loadRestrictions();
3121                 }
3122                 return isset( $this->mRestrictionsExpiry[$action] ) ? $this->mRestrictionsExpiry[$action] : false;
3123         }
3124
3125         /**
3126          * Returns cascading restrictions for the current article
3127          *
3128          * @return bool
3129          */
3130         function areRestrictionsCascading() {
3131                 if ( !$this->mRestrictionsLoaded ) {
3132                         $this->loadRestrictions();
3133                 }
3134
3135                 return $this->mCascadeRestriction;
3136         }
3137
3138         /**
3139          * Compiles list of active page restrictions from both page table (pre 1.10)
3140          * and page_restrictions table for this existing page.
3141          * Public for usage by LiquidThreads.
3142          *
3143          * @param array $rows Array of db result objects
3144          * @param string $oldFashionedRestrictions Comma-separated set of permission keys
3145          * indicating who can move or edit the page from the page table, (pre 1.10) rows.
3146          * Edit and move sections are separated by a colon
3147          * Example: "edit=autoconfirmed,sysop:move=sysop"
3148          */
3149         public function loadRestrictionsFromRows( $rows, $oldFashionedRestrictions = null ) {
3150                 $dbr = wfGetDB( DB_REPLICA );
3151
3152                 $restrictionTypes = $this->getRestrictionTypes();
3153
3154                 foreach ( $restrictionTypes as $type ) {
3155                         $this->mRestrictions[$type] = [];
3156                         $this->mRestrictionsExpiry[$type] = 'infinity';
3157                 }
3158
3159                 $this->mCascadeRestriction = false;
3160
3161                 # Backwards-compatibility: also load the restrictions from the page record (old format).
3162                 if ( $oldFashionedRestrictions !== null ) {
3163                         $this->mOldRestrictions = $oldFashionedRestrictions;
3164                 }
3165
3166                 if ( $this->mOldRestrictions === false ) {
3167                         $this->mOldRestrictions = $dbr->selectField( 'page', 'page_restrictions',
3168                                 [ 'page_id' => $this->getArticleID() ], __METHOD__ );
3169                 }
3170
3171                 if ( $this->mOldRestrictions != '' ) {
3172                         foreach ( explode( ':', trim( $this->mOldRestrictions ) ) as $restrict ) {
3173                                 $temp = explode( '=', trim( $restrict ) );
3174                                 if ( count( $temp ) == 1 ) {
3175                                         // old old format should be treated as edit/move restriction
3176                                         $this->mRestrictions['edit'] = explode( ',', trim( $temp[0] ) );
3177                                         $this->mRestrictions['move'] = explode( ',', trim( $temp[0] ) );
3178                                 } else {
3179                                         $restriction = trim( $temp[1] );
3180                                         if ( $restriction != '' ) { // some old entries are empty
3181                                                 $this->mRestrictions[$temp[0]] = explode( ',', $restriction );
3182                                         }
3183                                 }
3184                         }
3185                 }
3186
3187                 if ( count( $rows ) ) {
3188                         # Current system - load second to make them override.
3189                         $now = wfTimestampNow();
3190
3191                         # Cycle through all the restrictions.
3192                         foreach ( $rows as $row ) {
3193                                 // Don't take care of restrictions types that aren't allowed
3194                                 if ( !in_array( $row->pr_type, $restrictionTypes ) ) {
3195                                         continue;
3196                                 }
3197
3198                                 $expiry = $dbr->decodeExpiry( $row->pr_expiry );
3199
3200                                 // Only apply the restrictions if they haven't expired!
3201                                 if ( !$expiry || $expiry > $now ) {
3202                                         $this->mRestrictionsExpiry[$row->pr_type] = $expiry;
3203                                         $this->mRestrictions[$row->pr_type] = explode( ',', trim( $row->pr_level ) );
3204
3205                                         $this->mCascadeRestriction |= $row->pr_cascade;
3206                                 }
3207                         }
3208                 }
3209
3210                 $this->mRestrictionsLoaded = true;
3211         }
3212
3213         /**
3214          * Load restrictions from the page_restrictions table
3215          *
3216          * @param string $oldFashionedRestrictions Comma-separated set of permission keys
3217          * indicating who can move or edit the page from the page table, (pre 1.10) rows.
3218          * Edit and move sections are separated by a colon
3219          * Example: "edit=autoconfirmed,sysop:move=sysop"
3220          */
3221         public function loadRestrictions( $oldFashionedRestrictions = null ) {
3222                 if ( $this->mRestrictionsLoaded ) {
3223                         return;
3224                 }
3225
3226                 $id = $this->getArticleID();
3227                 if ( $id ) {
3228                         $cache = ObjectCache::getMainWANInstance();
3229                         $rows = $cache->getWithSetCallback(
3230                                 // Page protections always leave a new null revision
3231                                 $cache->makeKey( 'page-restrictions', $id, $this->getLatestRevID() ),
3232                                 $cache::TTL_DAY,
3233                                 function ( $curValue, &$ttl, array &$setOpts ) {
3234                                         $dbr = wfGetDB( DB_REPLICA );
3235
3236                                         $setOpts += Database::getCacheSetOptions( $dbr );
3237
3238                                         return iterator_to_array(
3239                                                 $dbr->select(
3240                                                         'page_restrictions',
3241                                                         [ 'pr_type', 'pr_expiry', 'pr_level', 'pr_cascade' ],
3242                                                         [ 'pr_page' => $this->getArticleID() ],
3243                                                         __METHOD__
3244                                                 )
3245                                         );
3246                                 }
3247                         );
3248
3249                         $this->loadRestrictionsFromRows( $rows, $oldFashionedRestrictions );
3250                 } else {
3251                         $title_protection = $this->getTitleProtectionInternal();
3252
3253                         if ( $title_protection ) {
3254                                 $now = wfTimestampNow();
3255                                 $expiry = wfGetDB( DB_REPLICA )->decodeExpiry( $title_protection['expiry'] );
3256
3257                                 if ( !$expiry || $expiry > $now ) {
3258                                         // Apply the restrictions
3259                                         $this->mRestrictionsExpiry['create'] = $expiry;
3260                                         $this->mRestrictions['create'] =
3261                                                 explode( ',', trim( $title_protection['permission'] ) );
3262                                 } else { // Get rid of the old restrictions
3263                                         $this->mTitleProtection = false;
3264                                 }
3265                         } else {
3266                                 $this->mRestrictionsExpiry['create'] = 'infinity';
3267                         }
3268                         $this->mRestrictionsLoaded = true;
3269                 }
3270         }
3271
3272         /**
3273          * Flush the protection cache in this object and force reload from the database.
3274          * This is used when updating protection from WikiPage::doUpdateRestrictions().
3275          */
3276         public function flushRestrictions() {
3277                 $this->mRestrictionsLoaded = false;
3278                 $this->mTitleProtection = null;
3279         }
3280
3281         /**
3282          * Purge expired restrictions from the page_restrictions table
3283          *
3284          * This will purge no more than $wgUpdateRowsPerQuery page_restrictions rows
3285          */
3286         static function purgeExpiredRestrictions() {
3287                 if ( wfReadOnly() ) {
3288                         return;
3289                 }
3290
3291                 DeferredUpdates::addUpdate( new AtomicSectionUpdate(
3292                         wfGetDB( DB_MASTER ),
3293                         __METHOD__,
3294                         function ( IDatabase $dbw, $fname ) {
3295                                 $config = MediaWikiServices::getInstance()->getMainConfig();
3296                                 $ids = $dbw->selectFieldValues(
3297                                         'page_restrictions',
3298                                         'pr_id',
3299                                         [ 'pr_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ],
3300                                         $fname,
3301                                         [ 'LIMIT' => $config->get( 'UpdateRowsPerQuery' ) ] // T135470
3302                                 );
3303                                 if ( $ids ) {
3304                                         $dbw->delete( 'page_restrictions', [ 'pr_id' => $ids ], $fname );
3305                                 }
3306                         }
3307                 ) );
3308
3309                 DeferredUpdates::addUpdate( new AtomicSectionUpdate(
3310                         wfGetDB( DB_MASTER ),
3311                         __METHOD__,
3312                         function ( IDatabase $dbw, $fname ) {
3313                                 $dbw->delete(
3314                                         'protected_titles',
3315                                         [ 'pt_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ],
3316                                         $fname
3317                                 );
3318                         }
3319                 ) );
3320         }
3321
3322         /**
3323          * Does this have subpages?  (Warning, usually requires an extra DB query.)
3324          *
3325          * @return bool
3326          */
3327         public function hasSubpages() {
3328                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
3329                         # Duh
3330                         return false;
3331                 }
3332
3333                 # We dynamically add a member variable for the purpose of this method
3334                 # alone to cache the result.  There's no point in having it hanging
3335                 # around uninitialized in every Title object; therefore we only add it
3336                 # if needed and don't declare it statically.
3337                 if ( $this->mHasSubpages === null ) {
3338                         $this->mHasSubpages = false;
3339                         $subpages = $this->getSubpages( 1 );
3340                         if ( $subpages instanceof TitleArray ) {
3341                                 $this->mHasSubpages = (bool)$subpages->count();
3342                         }
3343                 }
3344
3345                 return $this->mHasSubpages;
3346         }
3347
3348         /**
3349          * Get all subpages of this page.
3350          *
3351          * @param int $limit Maximum number of subpages to fetch; -1 for no limit
3352          * @return TitleArray|array TitleArray, or empty array if this page's namespace
3353          *  doesn't allow subpages
3354          */
3355         public function getSubpages( $limit = -1 ) {
3356                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3357                         return [];
3358                 }
3359
3360                 $dbr = wfGetDB( DB_REPLICA );
3361                 $conds['page_namespace'] = $this->getNamespace();
3362                 $conds[] = 'page_title ' . $dbr->buildLike( $this->getDBkey() . '/', $dbr->anyString() );
3363                 $options = [];
3364                 if ( $limit > -1 ) {
3365                         $options['LIMIT'] = $limit;
3366                 }
3367                 return TitleArray::newFromResult(
3368                         $dbr->select( 'page',
3369                                 [ 'page_id', 'page_namespace', 'page_title', 'page_is_redirect' ],
3370                                 $conds,
3371                                 __METHOD__,
3372                                 $options
3373                         )
3374                 );
3375         }
3376
3377         /**
3378          * Is there a version of this page in the deletion archive?
3379          *
3380          * @return int The number of archived revisions
3381          */
3382         public function isDeleted() {
3383                 if ( $this->getNamespace() < 0 ) {
3384                         $n = 0;
3385                 } else {
3386                         $dbr = wfGetDB( DB_REPLICA );
3387
3388                         $n = $dbr->selectField( 'archive', 'COUNT(*)',
3389                                 [ 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ],
3390                                 __METHOD__
3391                         );
3392                         if ( $this->getNamespace() == NS_FILE ) {
3393                                 $n += $dbr->selectField( 'filearchive', 'COUNT(*)',
3394                                         [ 'fa_name' => $this->getDBkey() ],
3395                                         __METHOD__
3396                                 );
3397                         }
3398                 }
3399                 return (int)$n;
3400         }
3401
3402         /**
3403          * Is there a version of this page in the deletion archive?
3404          *
3405          * @return bool
3406          */
3407         public function isDeletedQuick() {
3408                 if ( $this->getNamespace() < 0 ) {
3409                         return false;
3410                 }
3411                 $dbr = wfGetDB( DB_REPLICA );
3412                 $deleted = (bool)$dbr->selectField( 'archive', '1',
3413                         [ 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ],
3414                         __METHOD__
3415                 );
3416                 if ( !$deleted && $this->getNamespace() == NS_FILE ) {
3417                         $deleted = (bool)$dbr->selectField( 'filearchive', '1',
3418                                 [ 'fa_name' => $this->getDBkey() ],
3419                                 __METHOD__
3420                         );
3421                 }
3422                 return $deleted;
3423         }
3424
3425         /**
3426          * Get the article ID for this Title from the link cache,
3427          * adding it if necessary
3428          *
3429          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select
3430          *  for update
3431          * @return int The ID
3432          */
3433         public function getArticleID( $flags = 0 ) {
3434                 if ( $this->getNamespace() < 0 ) {
3435                         $this->mArticleID = 0;
3436                         return $this->mArticleID;
3437                 }
3438                 $linkCache = LinkCache::singleton();
3439                 if ( $flags & self::GAID_FOR_UPDATE ) {
3440                         $oldUpdate = $linkCache->forUpdate( true );
3441                         $linkCache->clearLink( $this );
3442                         $this->mArticleID = $linkCache->addLinkObj( $this );
3443                         $linkCache->forUpdate( $oldUpdate );
3444                 } else {
3445                         if ( -1 == $this->mArticleID ) {
3446                                 $this->mArticleID = $linkCache->addLinkObj( $this );
3447                         }
3448                 }
3449                 return $this->mArticleID;
3450         }
3451
3452         /**
3453          * Is this an article that is a redirect page?
3454          * Uses link cache, adding it if necessary
3455          *
3456          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3457          * @return bool
3458          */
3459         public function isRedirect( $flags = 0 ) {
3460                 if ( !is_null( $this->mRedirect ) ) {
3461                         return $this->mRedirect;
3462                 }
3463                 if ( !$this->getArticleID( $flags ) ) {
3464                         $this->mRedirect = false;
3465                         return $this->mRedirect;
3466                 }
3467
3468                 $linkCache = LinkCache::singleton();
3469                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3470                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'redirect' );
3471                 if ( $cached === null ) {
3472                         # Trust LinkCache's state over our own
3473                         # LinkCache is telling us that the page doesn't exist, despite there being cached
3474                         # data relating to an existing page in $this->mArticleID. Updaters should clear
3475                         # LinkCache as appropriate, or use $flags = Title::GAID_FOR_UPDATE. If that flag is
3476                         # set, then LinkCache will definitely be up to date here, since getArticleID() forces
3477                         # LinkCache to refresh its data from the master.
3478                         $this->mRedirect = false;
3479                         return $this->mRedirect;
3480                 }
3481
3482                 $this->mRedirect = (bool)$cached;
3483
3484                 return $this->mRedirect;
3485         }
3486
3487         /**
3488          * What is the length of this page?
3489          * Uses link cache, adding it if necessary
3490          *
3491          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3492          * @return int
3493          */
3494         public function getLength( $flags = 0 ) {
3495                 if ( $this->mLength != -1 ) {
3496                         return $this->mLength;
3497                 }
3498                 if ( !$this->getArticleID( $flags ) ) {
3499                         $this->mLength = 0;
3500                         return $this->mLength;
3501                 }
3502                 $linkCache = LinkCache::singleton();
3503                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3504                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'length' );
3505                 if ( $cached === null ) {
3506                         # Trust LinkCache's state over our own, as for isRedirect()
3507                         $this->mLength = 0;
3508                         return $this->mLength;
3509                 }
3510
3511                 $this->mLength = intval( $cached );
3512
3513                 return $this->mLength;
3514         }
3515
3516         /**
3517          * What is the page_latest field for this page?
3518          *
3519          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3520          * @return int Int or 0 if the page doesn't exist
3521          */
3522         public function getLatestRevID( $flags = 0 ) {
3523                 if ( !( $flags & self::GAID_FOR_UPDATE ) && $this->mLatestID !== false ) {
3524                         return intval( $this->mLatestID );
3525                 }
3526                 if ( !$this->getArticleID( $flags ) ) {
3527                         $this->mLatestID = 0;
3528                         return $this->mLatestID;
3529                 }
3530                 $linkCache = LinkCache::singleton();
3531                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3532                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'revision' );
3533                 if ( $cached === null ) {
3534                         # Trust LinkCache's state over our own, as for isRedirect()
3535                         $this->mLatestID = 0;
3536                         return $this->mLatestID;
3537                 }
3538
3539                 $this->mLatestID = intval( $cached );
3540
3541                 return $this->mLatestID;
3542         }
3543
3544         /**
3545          * This clears some fields in this object, and clears any associated
3546          * keys in the "bad links" section of the link cache.
3547          *
3548          * - This is called from WikiPage::doEditContent() and WikiPage::insertOn() to allow
3549          * loading of the new page_id. It's also called from
3550          * WikiPage::doDeleteArticleReal()
3551          *
3552          * @param int $newid The new Article ID
3553          */
3554         public function resetArticleID( $newid ) {
3555                 $linkCache = LinkCache::singleton();
3556                 $linkCache->clearLink( $this );
3557
3558                 if ( $newid === false ) {
3559                         $this->mArticleID = -1;
3560                 } else {
3561                         $this->mArticleID = intval( $newid );
3562                 }
3563                 $this->mRestrictionsLoaded = false;
3564                 $this->mRestrictions = [];
3565                 $this->mOldRestrictions = false;
3566                 $this->mRedirect = null;
3567                 $this->mLength = -1;
3568                 $this->mLatestID = false;
3569                 $this->mContentModel = false;
3570                 $this->mEstimateRevisions = null;
3571                 $this->mPageLanguage = false;
3572                 $this->mDbPageLanguage = false;
3573                 $this->mIsBigDeletion = null;
3574         }
3575
3576         public static function clearCaches() {
3577                 $linkCache = LinkCache::singleton();
3578                 $linkCache->clear();
3579
3580                 $titleCache = self::getTitleCache();
3581                 $titleCache->clear();
3582         }
3583
3584         /**
3585          * Capitalize a text string for a title if it belongs to a namespace that capitalizes
3586          *
3587          * @param string $text Containing title to capitalize
3588          * @param int $ns Namespace index, defaults to NS_MAIN
3589          * @return string Containing capitalized title
3590          */
3591         public static function capitalize( $text, $ns = NS_MAIN ) {
3592                 global $wgContLang;
3593
3594                 if ( MWNamespace::isCapitalized( $ns ) ) {
3595                         return $wgContLang->ucfirst( $text );
3596                 } else {
3597                         return $text;
3598                 }
3599         }
3600
3601         /**
3602          * Secure and split - main initialisation function for this object
3603          *
3604          * Assumes that mDbkeyform has been set, and is urldecoded
3605          * and uses underscores, but not otherwise munged.  This function
3606          * removes illegal characters, splits off the interwiki and
3607          * namespace prefixes, sets the other forms, and canonicalizes
3608          * everything.
3609          *
3610          * @throws MalformedTitleException On invalid titles
3611          * @return bool True on success
3612          */
3613         private function secureAndSplit() {
3614                 # Initialisation
3615                 $this->mInterwiki = '';
3616                 $this->mFragment = '';
3617                 $this->mNamespace = $this->mDefaultNamespace; # Usually NS_MAIN
3618
3619                 $dbkey = $this->mDbkeyform;
3620
3621                 // @note: splitTitleString() is a temporary hack to allow MediaWikiTitleCodec to share
3622                 //        the parsing code with Title, while avoiding massive refactoring.
3623                 // @todo: get rid of secureAndSplit, refactor parsing code.
3624                 // @note: getTitleParser() returns a TitleParser implementation which does not have a
3625                 //        splitTitleString method, but the only implementation (MediaWikiTitleCodec) does
3626                 $titleCodec = MediaWikiServices::getInstance()->getTitleParser();
3627                 // MalformedTitleException can be thrown here
3628                 $parts = $titleCodec->splitTitleString( $dbkey, $this->getDefaultNamespace() );
3629
3630                 # Fill fields
3631                 $this->setFragment( '#' . $parts['fragment'] );
3632                 $this->mInterwiki = $parts['interwiki'];
3633                 $this->mLocalInterwiki = $parts['local_interwiki'];
3634                 $this->mNamespace = $parts['namespace'];
3635                 $this->mUserCaseDBKey = $parts['user_case_dbkey'];
3636
3637                 $this->mDbkeyform = $parts['dbkey'];
3638                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
3639                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
3640
3641                 # We already know that some pages won't be in the database!
3642                 if ( $this->isExternal() || $this->isSpecialPage() ) {
3643                         $this->mArticleID = 0;
3644                 }
3645
3646                 return true;
3647         }
3648
3649         /**
3650          * Get an array of Title objects linking to this Title
3651          * Also stores the IDs in the link cache.
3652          *
3653          * WARNING: do not use this function on arbitrary user-supplied titles!
3654          * On heavily-used templates it will max out the memory.
3655          *
3656          * @param array $options May be FOR UPDATE
3657          * @param string $table Table name
3658          * @param string $prefix Fields prefix
3659          * @return Title[] Array of Title objects linking here
3660          */
3661         public function getLinksTo( $options = [], $table = 'pagelinks', $prefix = 'pl' ) {
3662                 if ( count( $options ) > 0 ) {
3663                         $db = wfGetDB( DB_MASTER );
3664                 } else {
3665                         $db = wfGetDB( DB_REPLICA );
3666                 }
3667
3668                 $res = $db->select(
3669                         [ 'page', $table ],
3670                         self::getSelectFields(),
3671                         [
3672                                 "{$prefix}_from=page_id",
3673                                 "{$prefix}_namespace" => $this->getNamespace(),
3674                                 "{$prefix}_title" => $this->getDBkey() ],
3675                         __METHOD__,
3676                         $options
3677                 );
3678
3679                 $retVal = [];
3680                 if ( $res->numRows() ) {
3681                         $linkCache = LinkCache::singleton();
3682                         foreach ( $res as $row ) {
3683                                 $titleObj = self::makeTitle( $row->page_namespace, $row->page_title );
3684                                 if ( $titleObj ) {
3685                                         $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3686                                         $retVal[] = $titleObj;
3687                                 }
3688                         }
3689                 }
3690                 return $retVal;
3691         }
3692
3693         /**
3694          * Get an array of Title objects using this Title as a template
3695          * Also stores the IDs in the link cache.
3696          *
3697          * WARNING: do not use this function on arbitrary user-supplied titles!
3698          * On heavily-used templates it will max out the memory.
3699          *
3700          * @param array $options Query option to Database::select()
3701          * @return Title[] Array of Title the Title objects linking here
3702          */
3703         public function getTemplateLinksTo( $options = [] ) {
3704                 return $this->getLinksTo( $options, 'templatelinks', 'tl' );
3705         }
3706
3707         /**
3708          * Get an array of Title objects linked from this Title
3709          * Also stores the IDs in the link cache.
3710          *
3711          * WARNING: do not use this function on arbitrary user-supplied titles!
3712          * On heavily-used templates it will max out the memory.
3713          *
3714          * @param array $options Query option to Database::select()
3715          * @param string $table Table name
3716          * @param string $prefix Fields prefix
3717          * @return array Array of Title objects linking here
3718          */
3719         public function getLinksFrom( $options = [], $table = 'pagelinks', $prefix = 'pl' ) {
3720                 $id = $this->getArticleID();
3721
3722                 # If the page doesn't exist; there can't be any link from this page
3723                 if ( !$id ) {
3724                         return [];
3725                 }
3726
3727                 $db = wfGetDB( DB_REPLICA );
3728
3729                 $blNamespace = "{$prefix}_namespace";
3730                 $blTitle = "{$prefix}_title";
3731
3732                 $pageQuery = WikiPage::getQueryInfo();
3733                 $res = $db->select(
3734                         [ $table, 'nestpage' => $pageQuery['tables'] ],
3735                         array_merge(
3736                                 [ $blNamespace, $blTitle ],
3737                                 $pageQuery['fields']
3738                         ),
3739                         [ "{$prefix}_from" => $id ],
3740                         __METHOD__,
3741                         $options,
3742                         [ 'nestpage' => [
3743                                 'LEFT JOIN',
3744                                 [ "page_namespace=$blNamespace", "page_title=$blTitle" ]
3745                         ] ] + $pageQuery['joins']
3746                 );
3747
3748                 $retVal = [];
3749                 $linkCache = LinkCache::singleton();
3750                 foreach ( $res as $row ) {
3751                         if ( $row->page_id ) {
3752                                 $titleObj = self::newFromRow( $row );
3753                         } else {
3754                                 $titleObj = self::makeTitle( $row->$blNamespace, $row->$blTitle );
3755                                 $linkCache->addBadLinkObj( $titleObj );
3756                         }
3757                         $retVal[] = $titleObj;
3758                 }
3759
3760                 return $retVal;
3761         }
3762
3763         /**
3764          * Get an array of Title objects used on this Title as a template
3765          * Also stores the IDs in the link cache.
3766          *
3767          * WARNING: do not use this function on arbitrary user-supplied titles!
3768          * On heavily-used templates it will max out the memory.
3769          *
3770          * @param array $options May be FOR UPDATE
3771          * @return Title[] Array of Title the Title objects used here
3772          */
3773         public function getTemplateLinksFrom( $options = [] ) {
3774                 return $this->getLinksFrom( $options, 'templatelinks', 'tl' );
3775         }
3776
3777         /**
3778          * Get an array of Title objects referring to non-existent articles linked
3779          * from this page.
3780          *
3781          * @todo check if needed (used only in SpecialBrokenRedirects.php, and
3782          *   should use redirect table in this case).
3783          * @return Title[] Array of Title the Title objects
3784          */
3785         public function getBrokenLinksFrom() {
3786                 if ( $this->getArticleID() == 0 ) {
3787                         # All links from article ID 0 are false positives
3788                         return [];
3789                 }
3790
3791                 $dbr = wfGetDB( DB_REPLICA );
3792                 $res = $dbr->select(
3793                         [ 'page', 'pagelinks' ],
3794                         [ 'pl_namespace', 'pl_title' ],
3795                         [
3796                                 'pl_from' => $this->getArticleID(),
3797                                 'page_namespace IS NULL'
3798                         ],
3799                         __METHOD__, [],
3800                         [
3801                                 'page' => [
3802                                         'LEFT JOIN',
3803                                         [ 'pl_namespace=page_namespace', 'pl_title=page_title' ]
3804                                 ]
3805                         ]
3806                 );
3807
3808                 $retVal = [];
3809                 foreach ( $res as $row ) {
3810                         $retVal[] = self::makeTitle( $row->pl_namespace, $row->pl_title );
3811                 }
3812                 return $retVal;
3813         }
3814
3815         /**
3816          * Get a list of URLs to purge from the CDN cache when this
3817          * page changes
3818          *
3819          * @return string[] Array of String the URLs
3820          */
3821         public function getCdnUrls() {
3822                 $urls = [
3823                         $this->getInternalURL(),
3824                         $this->getInternalURL( 'action=history' )
3825                 ];
3826
3827                 $pageLang = $this->getPageLanguage();
3828                 if ( $pageLang->hasVariants() ) {
3829                         $variants = $pageLang->getVariants();
3830                         foreach ( $variants as $vCode ) {
3831                                 $urls[] = $this->getInternalURL( $vCode );
3832                         }
3833                 }
3834
3835                 // If we are looking at a css/js user subpage, purge the action=raw.
3836                 if ( $this->isUserJsConfigPage() ) {
3837                         $urls[] = $this->getInternalURL( 'action=raw&ctype=text/javascript' );
3838                 } elseif ( $this->isUserJsonConfigPage() ) {
3839                         $urls[] = $this->getInternalURL( 'action=raw&ctype=application/json' );
3840                 } elseif ( $this->isUserCssConfigPage() ) {
3841                         $urls[] = $this->getInternalURL( 'action=raw&ctype=text/css' );
3842                 }
3843
3844                 Hooks::run( 'TitleSquidURLs', [ $this, &$urls ] );
3845                 return $urls;
3846         }
3847
3848         /**
3849          * @deprecated since 1.27 use getCdnUrls()
3850          */
3851         public function getSquidURLs() {
3852                 return $this->getCdnUrls();
3853         }
3854
3855         /**
3856          * Purge all applicable CDN URLs
3857          */
3858         public function purgeSquid() {
3859                 DeferredUpdates::addUpdate(
3860                         new CdnCacheUpdate( $this->getCdnUrls() ),
3861                         DeferredUpdates::PRESEND
3862                 );
3863         }
3864
3865         /**
3866          * Check whether a given move operation would be valid.
3867          * Returns true if ok, or a getUserPermissionsErrors()-like array otherwise
3868          *
3869          * @deprecated since 1.25, use MovePage's methods instead
3870          * @param Title &$nt The new title
3871          * @param bool $auth Whether to check user permissions (uses $wgUser)
3872          * @param string $reason Is the log summary of the move, used for spam checking
3873          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3874          */
3875         public function isValidMoveOperation( &$nt, $auth = true, $reason = '' ) {
3876                 global $wgUser;
3877
3878                 if ( !( $nt instanceof Title ) ) {
3879                         // Normally we'd add this to $errors, but we'll get
3880                         // lots of syntax errors if $nt is not an object
3881                         return [ [ 'badtitletext' ] ];
3882                 }
3883
3884                 $mp = new MovePage( $this, $nt );
3885                 $errors = $mp->isValidMove()->getErrorsArray();
3886                 if ( $auth ) {
3887                         $errors = wfMergeErrorArrays(
3888                                 $errors,
3889                                 $mp->checkPermissions( $wgUser, $reason )->getErrorsArray()
3890                         );
3891                 }
3892
3893                 return $errors ?: true;
3894         }
3895
3896         /**
3897          * Check if the requested move target is a valid file move target
3898          * @todo move this to MovePage
3899          * @param Title $nt Target title
3900          * @return array List of errors
3901          */
3902         protected function validateFileMoveOperation( $nt ) {
3903                 global $wgUser;
3904
3905                 $errors = [];
3906
3907                 $destFile = wfLocalFile( $nt );
3908                 $destFile->load( File::READ_LATEST );
3909                 if ( !$wgUser->isAllowed( 'reupload-shared' )
3910                         && !$destFile->exists() && wfFindFile( $nt )
3911                 ) {
3912                         $errors[] = [ 'file-exists-sharedrepo' ];
3913                 }
3914
3915                 return $errors;
3916         }
3917
3918         /**
3919          * Move a title to a new location
3920          *
3921          * @deprecated since 1.25, use the MovePage class instead
3922          * @param Title &$nt The new title
3923          * @param bool $auth Indicates whether $wgUser's permissions
3924          *  should be checked
3925          * @param string $reason The reason for the move
3926          * @param bool $createRedirect Whether to create a redirect from the old title to the new title.
3927          *  Ignored if the user doesn't have the suppressredirect right.
3928          * @param array $changeTags Applied to the entry in the move log and redirect page revision
3929          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3930          */
3931         public function moveTo( &$nt, $auth = true, $reason = '', $createRedirect = true,
3932                 array $changeTags = []
3933         ) {
3934                 global $wgUser;
3935                 $err = $this->isValidMoveOperation( $nt, $auth, $reason );
3936                 if ( is_array( $err ) ) {
3937                         // Auto-block user's IP if the account was "hard" blocked
3938                         $wgUser->spreadAnyEditBlock();
3939                         return $err;
3940                 }
3941                 // Check suppressredirect permission
3942                 if ( $auth && !$wgUser->isAllowed( 'suppressredirect' ) ) {
3943                         $createRedirect = true;
3944                 }
3945
3946                 $mp = new MovePage( $this, $nt );
3947                 $status = $mp->move( $wgUser, $reason, $createRedirect, $changeTags );
3948                 if ( $status->isOK() ) {
3949                         return true;
3950                 } else {
3951                         return $status->getErrorsArray();
3952                 }
3953         }
3954
3955         /**
3956          * Move this page's subpages to be subpages of $nt
3957          *
3958          * @param Title $nt Move target
3959          * @param bool $auth Whether $wgUser's permissions should be checked
3960          * @param string $reason The reason for the move
3961          * @param bool $createRedirect Whether to create redirects from the old subpages to
3962          *     the new ones Ignored if the user doesn't have the 'suppressredirect' right
3963          * @param array $changeTags Applied to the entry in the move log and redirect page revision
3964          * @return array Array with old page titles as keys, and strings (new page titles) or
3965          *     getUserPermissionsErrors()-like arrays (errors) as values, or a
3966          *     getUserPermissionsErrors()-like error array with numeric indices if
3967          *     no pages were moved
3968          */
3969         public function moveSubpages( $nt, $auth = true, $reason = '', $createRedirect = true,
3970                 array $changeTags = []
3971         ) {
3972                 global $wgMaximumMovedPages;
3973                 // Check permissions
3974                 if ( !$this->userCan( 'move-subpages' ) ) {
3975                         return [
3976                                 [ 'cant-move-subpages' ],
3977                         ];
3978                 }
3979                 // Do the source and target namespaces support subpages?
3980                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3981                         return [
3982                                 [ 'namespace-nosubpages', MWNamespace::getCanonicalName( $this->getNamespace() ) ],
3983                         ];
3984                 }
3985                 if ( !MWNamespace::hasSubpages( $nt->getNamespace() ) ) {
3986                         return [
3987                                 [ 'namespace-nosubpages', MWNamespace::getCanonicalName( $nt->getNamespace() ) ],
3988                         ];
3989                 }
3990
3991                 $subpages = $this->getSubpages( $wgMaximumMovedPages + 1 );
3992                 $retval = [];
3993                 $count = 0;
3994                 foreach ( $subpages as $oldSubpage ) {
3995                         $count++;
3996                         if ( $count > $wgMaximumMovedPages ) {
3997                                 $retval[$oldSubpage->getPrefixedText()] = [
3998                                         [ 'movepage-max-pages', $wgMaximumMovedPages ],
3999                                 ];
4000                                 break;
4001                         }
4002
4003                         // We don't know whether this function was called before
4004                         // or after moving the root page, so check both
4005                         // $this and $nt
4006                         if ( $oldSubpage->getArticleID() == $this->getArticleID()
4007                                 || $oldSubpage->getArticleID() == $nt->getArticleID()
4008                         ) {
4009                                 // When moving a page to a subpage of itself,
4010                                 // don't move it twice
4011                                 continue;
4012                         }
4013                         $newPageName = preg_replace(
4014                                         '#^' . preg_quote( $this->getDBkey(), '#' ) . '#',
4015                                         StringUtils::escapeRegexReplacement( $nt->getDBkey() ), # T23234
4016                                         $oldSubpage->getDBkey() );
4017                         if ( $oldSubpage->isTalkPage() ) {
4018                                 $newNs = $nt->getTalkPage()->getNamespace();
4019                         } else {
4020                                 $newNs = $nt->getSubjectPage()->getNamespace();
4021                         }
4022                         # T16385: we need makeTitleSafe because the new page names may
4023                         # be longer than 255 characters.
4024                         $newSubpage = self::makeTitleSafe( $newNs, $newPageName );
4025
4026                         $success = $oldSubpage->moveTo( $newSubpage, $auth, $reason, $createRedirect, $changeTags );
4027                         if ( $success === true ) {
4028                                 $retval[$oldSubpage->getPrefixedText()] = $newSubpage->getPrefixedText();
4029                         } else {
4030                                 $retval[$oldSubpage->getPrefixedText()] = $success;
4031                         }
4032                 }
4033                 return $retval;
4034         }
4035
4036         /**
4037          * Checks if this page is just a one-rev redirect.
4038          * Adds lock, so don't use just for light purposes.
4039          *
4040          * @return bool
4041          */
4042         public function isSingleRevRedirect() {
4043                 global $wgContentHandlerUseDB;
4044
4045                 $dbw = wfGetDB( DB_MASTER );
4046
4047                 # Is it a redirect?
4048                 $fields = [ 'page_is_redirect', 'page_latest', 'page_id' ];
4049                 if ( $wgContentHandlerUseDB ) {
4050                         $fields[] = 'page_content_model';
4051                 }
4052
4053                 $row = $dbw->selectRow( 'page',
4054                         $fields,
4055                         $this->pageCond(),
4056                         __METHOD__,
4057                         [ 'FOR UPDATE' ]
4058                 );
4059                 # Cache some fields we may want
4060                 $this->mArticleID = $row ? intval( $row->page_id ) : 0;
4061                 $this->mRedirect = $row ? (bool)$row->page_is_redirect : false;
4062                 $this->mLatestID = $row ? intval( $row->page_latest ) : false;
4063                 $this->mContentModel = $row && isset( $row->page_content_model )
4064                         ? strval( $row->page_content_model )
4065                         : false;
4066
4067                 if ( !$this->mRedirect ) {
4068                         return false;
4069                 }
4070                 # Does the article have a history?
4071                 $row = $dbw->selectField( [ 'page', 'revision' ],
4072                         'rev_id',
4073                         [ 'page_namespace' => $this->getNamespace(),
4074                                 'page_title' => $this->getDBkey(),
4075                                 'page_id=rev_page',
4076                                 'page_latest != rev_id'
4077                         ],
4078                         __METHOD__,
4079                         [ 'FOR UPDATE' ]
4080                 );
4081                 # Return true if there was no history
4082                 return ( $row === false );
4083         }
4084
4085         /**
4086          * Checks if $this can be moved to a given Title
4087          * - Selects for update, so don't call it unless you mean business
4088          *
4089          * @deprecated since 1.25, use MovePage's methods instead
4090          * @param Title $nt The new title to check
4091          * @return bool
4092          */
4093         public function isValidMoveTarget( $nt ) {
4094                 # Is it an existing file?
4095                 if ( $nt->getNamespace() == NS_FILE ) {
4096                         $file = wfLocalFile( $nt );
4097                         $file->load( File::READ_LATEST );
4098                         if ( $file->exists() ) {
4099                                 wfDebug( __METHOD__ . ": file exists\n" );
4100                                 return false;
4101                         }
4102                 }
4103                 # Is it a redirect with no history?
4104                 if ( !$nt->isSingleRevRedirect() ) {
4105                         wfDebug( __METHOD__ . ": not a one-rev redirect\n" );
4106                         return false;
4107                 }
4108                 # Get the article text
4109                 $rev = Revision::newFromTitle( $nt, false, Revision::READ_LATEST );
4110                 if ( !is_object( $rev ) ) {
4111                         return false;
4112                 }
4113                 $content = $rev->getContent();
4114                 # Does the redirect point to the source?
4115                 # Or is it a broken self-redirect, usually caused by namespace collisions?
4116                 $redirTitle = $content ? $content->getRedirectTarget() : null;
4117
4118                 if ( $redirTitle ) {
4119                         if ( $redirTitle->getPrefixedDBkey() != $this->getPrefixedDBkey() &&
4120                                 $redirTitle->getPrefixedDBkey() != $nt->getPrefixedDBkey() ) {
4121                                 wfDebug( __METHOD__ . ": redirect points to other page\n" );
4122                                 return false;
4123                         } else {
4124                                 return true;
4125                         }
4126                 } else {
4127                         # Fail safe (not a redirect after all. strange.)
4128                         wfDebug( __METHOD__ . ": failsafe: database sais " . $nt->getPrefixedDBkey() .
4129                                                 " is a redirect, but it doesn't contain a valid redirect.\n" );
4130                         return false;
4131                 }
4132         }
4133
4134         /**
4135          * Get categories to which this Title belongs and return an array of
4136          * categories' names.
4137          *
4138          * @return array Array of parents in the form:
4139          *     $parent => $currentarticle
4140          */
4141         public function getParentCategories() {
4142                 global $wgContLang;
4143
4144                 $data = [];
4145
4146                 $titleKey = $this->getArticleID();
4147
4148                 if ( $titleKey === 0 ) {
4149                         return $data;
4150                 }
4151
4152                 $dbr = wfGetDB( DB_REPLICA );
4153
4154                 $res = $dbr->select(
4155                         'categorylinks',
4156                         'cl_to',
4157                         [ 'cl_from' => $titleKey ],
4158                         __METHOD__
4159                 );
4160
4161                 if ( $res->numRows() > 0 ) {
4162                         foreach ( $res as $row ) {
4163                                 // $data[] = Title::newFromText($wgContLang->getNsText ( NS_CATEGORY ).':'.$row->cl_to);
4164                                 $data[$wgContLang->getNsText( NS_CATEGORY ) . ':' . $row->cl_to] = $this->getFullText();
4165                         }
4166                 }
4167                 return $data;
4168         }
4169
4170         /**
4171          * Get a tree of parent categories
4172          *
4173          * @param array $children Array with the children in the keys, to check for circular refs
4174          * @return array Tree of parent categories
4175          */
4176         public function getParentCategoryTree( $children = [] ) {
4177                 $stack = [];
4178                 $parents = $this->getParentCategories();
4179
4180                 if ( $parents ) {
4181                         foreach ( $parents as $parent => $current ) {
4182                                 if ( array_key_exists( $parent, $children ) ) {
4183                                         # Circular reference
4184                                         $stack[$parent] = [];
4185                                 } else {
4186                                         $nt = self::newFromText( $parent );
4187                                         if ( $nt ) {
4188                                                 $stack[$parent] = $nt->getParentCategoryTree( $children + [ $parent => 1 ] );
4189                                         }
4190                                 }
4191                         }
4192                 }
4193
4194                 return $stack;
4195         }
4196
4197         /**
4198          * Get an associative array for selecting this title from
4199          * the "page" table
4200          *
4201          * @return array Array suitable for the $where parameter of DB::select()
4202          */
4203         public function pageCond() {
4204                 if ( $this->mArticleID > 0 ) {
4205                         // PK avoids secondary lookups in InnoDB, shouldn't hurt other DBs
4206                         return [ 'page_id' => $this->mArticleID ];
4207                 } else {
4208                         return [ 'page_namespace' => $this->mNamespace, 'page_title' => $this->mDbkeyform ];
4209                 }
4210         }
4211
4212         /**
4213          * Get next/previous revision ID relative to another revision ID
4214          * @param int $revId Revision ID. Get the revision that was before this one.
4215          * @param int $flags Title::GAID_FOR_UPDATE
4216          * @param string $dir 'next' or 'prev'
4217          * @return int|bool New revision ID, or false if none exists
4218          */
4219         private function getRelativeRevisionID( $revId, $flags, $dir ) {
4220                 $revId = (int)$revId;
4221                 if ( $dir === 'next' ) {
4222                         $op = '>';
4223                         $sort = 'ASC';
4224                 } elseif ( $dir === 'prev' ) {
4225                         $op = '<';
4226                         $sort = 'DESC';
4227                 } else {
4228                         throw new InvalidArgumentException( '$dir must be "next" or "prev"' );
4229                 }
4230
4231                 if ( $flags & self::GAID_FOR_UPDATE ) {
4232                         $db = wfGetDB( DB_MASTER );
4233                 } else {
4234                         $db = wfGetDB( DB_REPLICA, 'contributions' );
4235                 }
4236
4237                 // Intentionally not caring if the specified revision belongs to this
4238                 // page. We only care about the timestamp.
4239                 $ts = $db->selectField( 'revision', 'rev_timestamp', [ 'rev_id' => $revId ], __METHOD__ );
4240                 if ( $ts === false ) {
4241                         $ts = $db->selectField( 'archive', 'ar_timestamp', [ 'ar_rev_id' => $revId ], __METHOD__ );
4242                         if ( $ts === false ) {
4243                                 // Or should this throw an InvalidArgumentException or something?
4244                                 return false;
4245                         }
4246                 }
4247                 $ts = $db->addQuotes( $ts );
4248
4249                 $revId = $db->selectField( 'revision', 'rev_id',
4250                         [
4251                                 'rev_page' => $this->getArticleID( $flags ),
4252                                 "rev_timestamp $op $ts OR (rev_timestamp = $ts AND rev_id $op $revId)"
4253                         ],
4254                         __METHOD__,
4255                         [
4256                                 'ORDER BY' => "rev_timestamp $sort, rev_id $sort",
4257                                 'IGNORE INDEX' => 'rev_timestamp', // Probably needed for T159319
4258                         ]
4259                 );
4260
4261                 if ( $revId === false ) {
4262                         return false;
4263                 } else {
4264                         return intval( $revId );
4265                 }
4266         }
4267
4268         /**
4269          * Get the revision ID of the previous revision
4270          *
4271          * @param int $revId Revision ID. Get the revision that was before this one.
4272          * @param int $flags Title::GAID_FOR_UPDATE
4273          * @return int|bool Old revision ID, or false if none exists
4274          */
4275         public function getPreviousRevisionID( $revId, $flags = 0 ) {
4276                 return $this->getRelativeRevisionID( $revId, $flags, 'prev' );
4277         }
4278
4279         /**
4280          * Get the revision ID of the next revision
4281          *
4282          * @param int $revId Revision ID. Get the revision that was after this one.
4283          * @param int $flags Title::GAID_FOR_UPDATE
4284          * @return int|bool Next revision ID, or false if none exists
4285          */
4286         public function getNextRevisionID( $revId, $flags = 0 ) {
4287                 return $this->getRelativeRevisionID( $revId, $flags, 'next' );
4288         }
4289
4290         /**
4291          * Get the first revision of the page
4292          *
4293          * @param int $flags Title::GAID_FOR_UPDATE
4294          * @return Revision|null If page doesn't exist
4295          */
4296         public function getFirstRevision( $flags = 0 ) {
4297                 $pageId = $this->getArticleID( $flags );
4298                 if ( $pageId ) {
4299                         $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_REPLICA );
4300                         $revQuery = Revision::getQueryInfo();
4301                         $row = $db->selectRow( $revQuery['tables'], $revQuery['fields'],
4302                                 [ 'rev_page' => $pageId ],
4303                                 __METHOD__,
4304                                 [
4305                                         'ORDER BY' => 'rev_timestamp ASC, rev_id ASC',
4306                                         'IGNORE INDEX' => [ 'revision' => 'rev_timestamp' ], // See T159319
4307                                 ],
4308                                 $revQuery['joins']
4309                         );
4310                         if ( $row ) {
4311                                 return new Revision( $row );
4312                         }
4313                 }
4314                 return null;
4315         }
4316
4317         /**
4318          * Get the oldest revision timestamp of this page
4319          *
4320          * @param int $flags Title::GAID_FOR_UPDATE
4321          * @return string MW timestamp
4322          */
4323         public function getEarliestRevTime( $flags = 0 ) {
4324                 $rev = $this->getFirstRevision( $flags );
4325                 return $rev ? $rev->getTimestamp() : null;
4326         }
4327
4328         /**
4329          * Check if this is a new page
4330          *
4331          * @return bool
4332          */
4333         public function isNewPage() {
4334                 $dbr = wfGetDB( DB_REPLICA );
4335                 return (bool)$dbr->selectField( 'page', 'page_is_new', $this->pageCond(), __METHOD__ );
4336         }
4337
4338         /**
4339          * Check whether the number of revisions of this page surpasses $wgDeleteRevisionsLimit
4340          *
4341          * @return bool
4342          */
4343         public function isBigDeletion() {
4344                 global $wgDeleteRevisionsLimit;
4345
4346                 if ( !$wgDeleteRevisionsLimit ) {
4347                         return false;
4348                 }
4349
4350                 if ( $this->mIsBigDeletion === null ) {
4351                         $dbr = wfGetDB( DB_REPLICA );
4352
4353                         $revCount = $dbr->selectRowCount(
4354                                 'revision',
4355                                 '1',
4356                                 [ 'rev_page' => $this->getArticleID() ],
4357                                 __METHOD__,
4358                                 [ 'LIMIT' => $wgDeleteRevisionsLimit + 1 ]
4359                         );
4360
4361                         $this->mIsBigDeletion = $revCount > $wgDeleteRevisionsLimit;
4362                 }
4363
4364                 return $this->mIsBigDeletion;
4365         }
4366
4367         /**
4368          * Get the approximate revision count of this page.
4369          *
4370          * @return int
4371          */
4372         public function estimateRevisionCount() {
4373                 if ( !$this->exists() ) {
4374                         return 0;
4375                 }
4376
4377                 if ( $this->mEstimateRevisions === null ) {
4378                         $dbr = wfGetDB( DB_REPLICA );
4379                         $this->mEstimateRevisions = $dbr->estimateRowCount( 'revision', '*',
4380                                 [ 'rev_page' => $this->getArticleID() ], __METHOD__ );
4381                 }
4382
4383                 return $this->mEstimateRevisions;
4384         }
4385
4386         /**
4387          * Get the number of revisions between the given revision.
4388          * Used for diffs and other things that really need it.
4389          *
4390          * @param int|Revision $old Old revision or rev ID (first before range)
4391          * @param int|Revision $new New revision or rev ID (first after range)
4392          * @param int|null $max Limit of Revisions to count, will be incremented to detect truncations
4393          * @return int Number of revisions between these revisions.
4394          */
4395         public function countRevisionsBetween( $old, $new, $max = null ) {
4396                 if ( !( $old instanceof Revision ) ) {
4397                         $old = Revision::newFromTitle( $this, (int)$old );
4398                 }
4399                 if ( !( $new instanceof Revision ) ) {
4400                         $new = Revision::newFromTitle( $this, (int)$new );
4401                 }
4402                 if ( !$old || !$new ) {
4403                         return 0; // nothing to compare
4404                 }
4405                 $dbr = wfGetDB( DB_REPLICA );
4406                 $conds = [
4407                         'rev_page' => $this->getArticleID(),
4408                         'rev_timestamp > ' . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4409                         'rev_timestamp < ' . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4410                 ];
4411                 if ( $max !== null ) {
4412                         return $dbr->selectRowCount( 'revision', '1',
4413                                 $conds,
4414                                 __METHOD__,
4415                                 [ 'LIMIT' => $max + 1 ] // extra to detect truncation
4416                         );
4417                 } else {
4418                         return (int)$dbr->selectField( 'revision', 'count(*)', $conds, __METHOD__ );
4419                 }
4420         }
4421
4422         /**
4423          * Get the authors between the given revisions or revision IDs.
4424          * Used for diffs and other things that really need it.
4425          *
4426          * @since 1.23
4427          *
4428          * @param int|Revision $old Old revision or rev ID (first before range by default)
4429          * @param int|Revision $new New revision or rev ID (first after range by default)
4430          * @param int $limit Maximum number of authors
4431          * @param string|array $options (Optional): Single option, or an array of options:
4432          *     'include_old' Include $old in the range; $new is excluded.
4433          *     'include_new' Include $new in the range; $old is excluded.
4434          *     'include_both' Include both $old and $new in the range.
4435          *     Unknown option values are ignored.
4436          * @return array|null Names of revision authors in the range; null if not both revisions exist
4437          */
4438         public function getAuthorsBetween( $old, $new, $limit, $options = [] ) {
4439                 if ( !( $old instanceof Revision ) ) {
4440                         $old = Revision::newFromTitle( $this, (int)$old );
4441                 }
4442                 if ( !( $new instanceof Revision ) ) {
4443                         $new = Revision::newFromTitle( $this, (int)$new );
4444                 }
4445                 // XXX: what if Revision objects are passed in, but they don't refer to this title?
4446                 // Add $old->getPage() != $new->getPage() || $old->getPage() != $this->getArticleID()
4447                 // in the sanity check below?
4448                 if ( !$old || !$new ) {
4449                         return null; // nothing to compare
4450                 }
4451                 $authors = [];
4452                 $old_cmp = '>';
4453                 $new_cmp = '<';
4454                 $options = (array)$options;
4455                 if ( in_array( 'include_old', $options ) ) {
4456                         $old_cmp = '>=';
4457                 }
4458                 if ( in_array( 'include_new', $options ) ) {
4459                         $new_cmp = '<=';
4460                 }
4461                 if ( in_array( 'include_both', $options ) ) {
4462                         $old_cmp = '>=';
4463                         $new_cmp = '<=';
4464                 }
4465                 // No DB query needed if $old and $new are the same or successive revisions:
4466                 if ( $old->getId() === $new->getId() ) {
4467                         return ( $old_cmp === '>' && $new_cmp === '<' ) ?
4468                                 [] :
4469                                 [ $old->getUserText( Revision::RAW ) ];
4470                 } elseif ( $old->getId() === $new->getParentId() ) {
4471                         if ( $old_cmp === '>=' && $new_cmp === '<=' ) {
4472                                 $authors[] = $old->getUserText( Revision::RAW );
4473                                 if ( $old->getUserText( Revision::RAW ) != $new->getUserText( Revision::RAW ) ) {
4474                                         $authors[] = $new->getUserText( Revision::RAW );
4475                                 }
4476                         } elseif ( $old_cmp === '>=' ) {
4477                                 $authors[] = $old->getUserText( Revision::RAW );
4478                         } elseif ( $new_cmp === '<=' ) {
4479                                 $authors[] = $new->getUserText( Revision::RAW );
4480                         }
4481                         return $authors;
4482                 }
4483                 $dbr = wfGetDB( DB_REPLICA );
4484                 $revQuery = Revision::getQueryInfo();
4485                 $authors = $dbr->selectFieldValues(
4486                         $revQuery['tables'],
4487                         $revQuery['fields']['rev_user_text'],
4488                         [
4489                                 'rev_page' => $this->getArticleID(),
4490                                 "rev_timestamp $old_cmp " . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4491                                 "rev_timestamp $new_cmp " . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4492                         ], __METHOD__,
4493                         [ 'DISTINCT', 'LIMIT' => $limit + 1 ], // add one so caller knows it was truncated
4494                         $revQuery['joins']
4495                 );
4496                 return $authors;
4497         }
4498
4499         /**
4500          * Get the number of authors between the given revisions or revision IDs.
4501          * Used for diffs and other things that really need it.
4502          *
4503          * @param int|Revision $old Old revision or rev ID (first before range by default)
4504          * @param int|Revision $new New revision or rev ID (first after range by default)
4505          * @param int $limit Maximum number of authors
4506          * @param string|array $options (Optional): Single option, or an array of options:
4507          *     'include_old' Include $old in the range; $new is excluded.
4508          *     'include_new' Include $new in the range; $old is excluded.
4509          *     'include_both' Include both $old and $new in the range.
4510          *     Unknown option values are ignored.
4511          * @return int Number of revision authors in the range; zero if not both revisions exist
4512          */
4513         public function countAuthorsBetween( $old, $new, $limit, $options = [] ) {
4514                 $authors = $this->getAuthorsBetween( $old, $new, $limit, $options );
4515                 return $authors ? count( $authors ) : 0;
4516         }
4517
4518         /**
4519          * Compare with another title.
4520          *
4521          * @param Title $title
4522          * @return bool
4523          */
4524         public function equals( Title $title ) {
4525                 // Note: === is necessary for proper matching of number-like titles.
4526                 return $this->getInterwiki() === $title->getInterwiki()
4527                         && $this->getNamespace() == $title->getNamespace()
4528                         && $this->getDBkey() === $title->getDBkey();
4529         }
4530
4531         /**
4532          * Check if this title is a subpage of another title
4533          *
4534          * @param Title $title
4535          * @return bool
4536          */
4537         public function isSubpageOf( Title $title ) {
4538                 return $this->getInterwiki() === $title->getInterwiki()
4539                         && $this->getNamespace() == $title->getNamespace()
4540                         && strpos( $this->getDBkey(), $title->getDBkey() . '/' ) === 0;
4541         }
4542
4543         /**
4544          * Check if page exists.  For historical reasons, this function simply
4545          * checks for the existence of the title in the page table, and will
4546          * thus return false for interwiki links, special pages and the like.
4547          * If you want to know if a title can be meaningfully viewed, you should
4548          * probably call the isKnown() method instead.
4549          *
4550          * @param int $flags An optional bit field; may be Title::GAID_FOR_UPDATE to check
4551          *   from master/for update
4552          * @return bool
4553          */
4554         public function exists( $flags = 0 ) {
4555                 $exists = $this->getArticleID( $flags ) != 0;
4556                 Hooks::run( 'TitleExists', [ $this, &$exists ] );
4557                 return $exists;
4558         }
4559
4560         /**
4561          * Should links to this title be shown as potentially viewable (i.e. as
4562          * "bluelinks"), even if there's no record by this title in the page
4563          * table?
4564          *
4565          * This function is semi-deprecated for public use, as well as somewhat
4566          * misleadingly named.  You probably just want to call isKnown(), which
4567          * calls this function internally.
4568          *
4569          * (ISSUE: Most of these checks are cheap, but the file existence check
4570          * can potentially be quite expensive.  Including it here fixes a lot of
4571          * existing code, but we might want to add an optional parameter to skip
4572          * it and any other expensive checks.)
4573          *
4574          * @return bool
4575          */
4576         public function isAlwaysKnown() {
4577                 $isKnown = null;
4578
4579                 /**
4580                  * Allows overriding default behavior for determining if a page exists.
4581                  * If $isKnown is kept as null, regular checks happen. If it's
4582                  * a boolean, this value is returned by the isKnown method.
4583                  *
4584                  * @since 1.20
4585                  *
4586                  * @param Title $title
4587                  * @param bool|null $isKnown
4588                  */
4589                 Hooks::run( 'TitleIsAlwaysKnown', [ $this, &$isKnown ] );
4590
4591                 if ( !is_null( $isKnown ) ) {
4592                         return $isKnown;
4593                 }
4594
4595                 if ( $this->isExternal() ) {
4596                         return true; // any interwiki link might be viewable, for all we know
4597                 }
4598
4599                 switch ( $this->mNamespace ) {
4600                         case NS_MEDIA:
4601                         case NS_FILE:
4602                                 // file exists, possibly in a foreign repo
4603                                 return (bool)wfFindFile( $this );
4604                         case NS_SPECIAL:
4605                                 // valid special page
4606                                 return SpecialPageFactory::exists( $this->getDBkey() );
4607                         case NS_MAIN:
4608                                 // selflink, possibly with fragment
4609                                 return $this->mDbkeyform == '';
4610                         case NS_MEDIAWIKI:
4611                                 // known system message
4612                                 return $this->hasSourceText() !== false;
4613                         default:
4614                                 return false;
4615                 }
4616         }
4617
4618         /**
4619          * Does this title refer to a page that can (or might) be meaningfully
4620          * viewed?  In particular, this function may be used to determine if
4621          * links to the title should be rendered as "bluelinks" (as opposed to
4622          * "redlinks" to non-existent pages).
4623          * Adding something else to this function will cause inconsistency
4624          * since LinkHolderArray calls isAlwaysKnown() and does its own
4625          * page existence check.
4626          *
4627          * @return bool
4628          */
4629         public function isKnown() {
4630                 return $this->isAlwaysKnown() || $this->exists();
4631         }
4632
4633         /**
4634          * Does this page have source text?
4635          *
4636          * @return bool
4637          */
4638         public function hasSourceText() {
4639                 if ( $this->exists() ) {
4640                         return true;
4641                 }
4642
4643                 if ( $this->mNamespace == NS_MEDIAWIKI ) {
4644                         // If the page doesn't exist but is a known system message, default
4645                         // message content will be displayed, same for language subpages-
4646                         // Use always content language to avoid loading hundreds of languages
4647                         // to get the link color.
4648                         global $wgContLang;
4649                         list( $name, ) = MessageCache::singleton()->figureMessage(
4650                                 $wgContLang->lcfirst( $this->getText() )
4651                         );
4652                         $message = wfMessage( $name )->inLanguage( $wgContLang )->useDatabase( false );
4653                         return $message->exists();
4654                 }
4655
4656                 return false;
4657         }
4658
4659         /**
4660          * Get the default message text or false if the message doesn't exist
4661          *
4662          * @return string|bool
4663          */
4664         public function getDefaultMessageText() {
4665                 global $wgContLang;
4666
4667                 if ( $this->getNamespace() != NS_MEDIAWIKI ) { // Just in case
4668                         return false;
4669                 }
4670
4671                 list( $name, $lang ) = MessageCache::singleton()->figureMessage(
4672                         $wgContLang->lcfirst( $this->getText() )
4673                 );
4674                 $message = wfMessage( $name )->inLanguage( $lang )->useDatabase( false );
4675
4676                 if ( $message->exists() ) {
4677                         return $message->plain();
4678                 } else {
4679                         return false;
4680                 }
4681         }
4682
4683         /**
4684          * Updates page_touched for this page; called from LinksUpdate.php
4685          *
4686          * @param string $purgeTime [optional] TS_MW timestamp
4687          * @return bool True if the update succeeded
4688          */
4689         public function invalidateCache( $purgeTime = null ) {
4690                 if ( wfReadOnly() ) {
4691                         return false;
4692                 } elseif ( $this->mArticleID === 0 ) {
4693                         return true; // avoid gap locking if we know it's not there
4694                 }
4695
4696                 $dbw = wfGetDB( DB_MASTER );
4697                 $dbw->onTransactionPreCommitOrIdle( function () {
4698                         ResourceLoaderWikiModule::invalidateModuleCache( $this, null, null, wfWikiID() );
4699                 } );
4700
4701                 $conds = $this->pageCond();
4702                 DeferredUpdates::addUpdate(
4703                         new AutoCommitUpdate(
4704                                 $dbw,
4705                                 __METHOD__,
4706                                 function ( IDatabase $dbw, $fname ) use ( $conds, $purgeTime ) {
4707                                         $dbTimestamp = $dbw->timestamp( $purgeTime ?: time() );
4708                                         $dbw->update(
4709                                                 'page',
4710                                                 [ 'page_touched' => $dbTimestamp ],
4711                                                 $conds + [ 'page_touched < ' . $dbw->addQuotes( $dbTimestamp ) ],
4712                                                 $fname
4713                                         );
4714                                         MediaWikiServices::getInstance()->getLinkCache()->invalidateTitle( $this );
4715                                 }
4716                         ),
4717                         DeferredUpdates::PRESEND
4718                 );
4719
4720                 return true;
4721         }
4722
4723         /**
4724          * Update page_touched timestamps and send CDN purge messages for
4725          * pages linking to this title. May be sent to the job queue depending
4726          * on the number of links. Typically called on create and delete.
4727          */
4728         public function touchLinks() {
4729                 DeferredUpdates::addUpdate( new HTMLCacheUpdate( $this, 'pagelinks', 'page-touch' ) );
4730                 if ( $this->getNamespace() == NS_CATEGORY ) {
4731                         DeferredUpdates::addUpdate(
4732                                 new HTMLCacheUpdate( $this, 'categorylinks', 'category-touch' )
4733                         );
4734                 }
4735         }
4736
4737         /**
4738          * Get the last touched timestamp
4739          *
4740          * @param IDatabase|null $db
4741          * @return string|false Last-touched timestamp
4742          */
4743         public function getTouched( $db = null ) {
4744                 if ( $db === null ) {
4745                         $db = wfGetDB( DB_REPLICA );
4746                 }
4747                 $touched = $db->selectField( 'page', 'page_touched', $this->pageCond(), __METHOD__ );
4748                 return $touched;
4749         }
4750
4751         /**
4752          * Get the timestamp when this page was updated since the user last saw it.
4753          *
4754          * @param User $user
4755          * @return string|null
4756          */
4757         public function getNotificationTimestamp( $user = null ) {
4758                 global $wgUser;
4759
4760                 // Assume current user if none given
4761                 if ( !$user ) {
4762                         $user = $wgUser;
4763                 }
4764                 // Check cache first
4765                 $uid = $user->getId();
4766                 if ( !$uid ) {
4767                         return false;
4768                 }
4769                 // avoid isset here, as it'll return false for null entries
4770                 if ( array_key_exists( $uid, $this->mNotificationTimestamp ) ) {
4771                         return $this->mNotificationTimestamp[$uid];
4772                 }
4773                 // Don't cache too much!
4774                 if ( count( $this->mNotificationTimestamp ) >= self::CACHE_MAX ) {
4775                         $this->mNotificationTimestamp = [];
4776                 }
4777
4778                 $store = MediaWikiServices::getInstance()->getWatchedItemStore();
4779                 $watchedItem = $store->getWatchedItem( $user, $this );
4780                 if ( $watchedItem ) {
4781                         $this->mNotificationTimestamp[$uid] = $watchedItem->getNotificationTimestamp();
4782                 } else {
4783                         $this->mNotificationTimestamp[$uid] = false;
4784                 }
4785
4786                 return $this->mNotificationTimestamp[$uid];
4787         }
4788
4789         /**
4790          * Generate strings used for xml 'id' names in monobook tabs
4791          *
4792          * @param string $prepend Defaults to 'nstab-'
4793          * @return string XML 'id' name
4794          */
4795         public function getNamespaceKey( $prepend = 'nstab-' ) {
4796                 global $wgContLang;
4797                 // Gets the subject namespace of this title
4798                 $subjectNS = MWNamespace::getSubject( $this->getNamespace() );
4799                 // Prefer canonical namespace name for HTML IDs
4800                 $namespaceKey = MWNamespace::getCanonicalName( $subjectNS );
4801                 if ( $namespaceKey === false ) {
4802                         // Fallback to localised text
4803                         $namespaceKey = $this->getSubjectNsText();
4804                 }
4805                 // Makes namespace key lowercase
4806                 $namespaceKey = $wgContLang->lc( $namespaceKey );
4807                 // Uses main
4808                 if ( $namespaceKey == '' ) {
4809                         $namespaceKey = 'main';
4810                 }
4811                 // Changes file to image for backwards compatibility
4812                 if ( $namespaceKey == 'file' ) {
4813                         $namespaceKey = 'image';
4814                 }
4815                 return $prepend . $namespaceKey;
4816         }
4817
4818         /**
4819          * Get all extant redirects to this Title
4820          *
4821          * @param int|null $ns Single namespace to consider; null to consider all namespaces
4822          * @return Title[] Array of Title redirects to this title
4823          */
4824         public function getRedirectsHere( $ns = null ) {
4825                 $redirs = [];
4826
4827                 $dbr = wfGetDB( DB_REPLICA );
4828                 $where = [
4829                         'rd_namespace' => $this->getNamespace(),
4830                         'rd_title' => $this->getDBkey(),
4831                         'rd_from = page_id'
4832                 ];
4833                 if ( $this->isExternal() ) {
4834                         $where['rd_interwiki'] = $this->getInterwiki();
4835                 } else {
4836                         $where[] = 'rd_interwiki = ' . $dbr->addQuotes( '' ) . ' OR rd_interwiki IS NULL';
4837                 }
4838                 if ( !is_null( $ns ) ) {
4839                         $where['page_namespace'] = $ns;
4840                 }
4841
4842                 $res = $dbr->select(
4843                         [ 'redirect', 'page' ],
4844                         [ 'page_namespace', 'page_title' ],
4845                         $where,
4846                         __METHOD__
4847                 );
4848
4849                 foreach ( $res as $row ) {
4850                         $redirs[] = self::newFromRow( $row );
4851                 }
4852                 return $redirs;
4853         }
4854
4855         /**
4856          * Check if this Title is a valid redirect target
4857          *
4858          * @return bool
4859          */
4860         public function isValidRedirectTarget() {
4861                 global $wgInvalidRedirectTargets;
4862
4863                 if ( $this->isSpecialPage() ) {
4864                         // invalid redirect targets are stored in a global array, but explicitly disallow Userlogout here
4865                         if ( $this->isSpecial( 'Userlogout' ) ) {
4866                                 return false;
4867                         }
4868
4869                         foreach ( $wgInvalidRedirectTargets as $target ) {
4870                                 if ( $this->isSpecial( $target ) ) {
4871                                         return false;
4872                                 }
4873                         }
4874                 }
4875
4876                 return true;
4877         }
4878
4879         /**
4880          * Get a backlink cache object
4881          *
4882          * @return BacklinkCache
4883          */
4884         public function getBacklinkCache() {
4885                 return BacklinkCache::get( $this );
4886         }
4887
4888         /**
4889          * Whether the magic words __INDEX__ and __NOINDEX__ function for this page.
4890          *
4891          * @return bool
4892          */
4893         public function canUseNoindex() {
4894                 global $wgExemptFromUserRobotsControl;
4895
4896                 $bannedNamespaces = is_null( $wgExemptFromUserRobotsControl )
4897                         ? MWNamespace::getContentNamespaces()
4898                         : $wgExemptFromUserRobotsControl;
4899
4900                 return !in_array( $this->mNamespace, $bannedNamespaces );
4901         }
4902
4903         /**
4904          * Returns the raw sort key to be used for categories, with the specified
4905          * prefix.  This will be fed to Collation::getSortKey() to get a
4906          * binary sortkey that can be used for actual sorting.
4907          *
4908          * @param string $prefix The prefix to be used, specified using
4909          *   {{defaultsort:}} or like [[Category:Foo|prefix]].  Empty for no
4910          *   prefix.
4911          * @return string
4912          */
4913         public function getCategorySortkey( $prefix = '' ) {
4914                 $unprefixed = $this->getText();
4915
4916                 // Anything that uses this hook should only depend
4917                 // on the Title object passed in, and should probably
4918                 // tell the users to run updateCollations.php --force
4919                 // in order to re-sort existing category relations.
4920                 Hooks::run( 'GetDefaultSortkey', [ $this, &$unprefixed ] );
4921                 if ( $prefix !== '' ) {
4922                         # Separate with a line feed, so the unprefixed part is only used as
4923                         # a tiebreaker when two pages have the exact same prefix.
4924                         # In UCA, tab is the only character that can sort above LF
4925                         # so we strip both of them from the original prefix.
4926                         $prefix = strtr( $prefix, "\n\t", '  ' );
4927                         return "$prefix\n$unprefixed";
4928                 }
4929                 return $unprefixed;
4930         }
4931
4932         /**
4933          * Returns the page language code saved in the database, if $wgPageLanguageUseDB is set
4934          * to true in LocalSettings.php, otherwise returns false. If there is no language saved in
4935          * the db, it will return NULL.
4936          *
4937          * @return string|null|bool
4938          */
4939         private function getDbPageLanguageCode() {
4940                 global $wgPageLanguageUseDB;
4941
4942                 // check, if the page language could be saved in the database, and if so and
4943                 // the value is not requested already, lookup the page language using LinkCache
4944                 if ( $wgPageLanguageUseDB && $this->mDbPageLanguage === false ) {
4945                         $linkCache = LinkCache::singleton();
4946                         $linkCache->addLinkObj( $this );
4947                         $this->mDbPageLanguage = $linkCache->getGoodLinkFieldObj( $this, 'lang' );
4948                 }
4949
4950                 return $this->mDbPageLanguage;
4951         }
4952
4953         /**
4954          * Get the language in which the content of this page is written in
4955          * wikitext. Defaults to $wgContLang, but in certain cases it can be
4956          * e.g. $wgLang (such as special pages, which are in the user language).
4957          *
4958          * @since 1.18
4959          * @return Language
4960          */
4961         public function getPageLanguage() {
4962                 global $wgLang, $wgLanguageCode;
4963                 if ( $this->isSpecialPage() ) {
4964                         // special pages are in the user language
4965                         return $wgLang;
4966                 }
4967
4968                 // Checking if DB language is set
4969                 $dbPageLanguage = $this->getDbPageLanguageCode();
4970                 if ( $dbPageLanguage ) {
4971                         return wfGetLangObj( $dbPageLanguage );
4972                 }
4973
4974                 if ( !$this->mPageLanguage || $this->mPageLanguage[1] !== $wgLanguageCode ) {
4975                         // Note that this may depend on user settings, so the cache should
4976                         // be only per-request.
4977                         // NOTE: ContentHandler::getPageLanguage() may need to load the
4978                         // content to determine the page language!
4979                         // Checking $wgLanguageCode hasn't changed for the benefit of unit
4980                         // tests.
4981                         $contentHandler = ContentHandler::getForTitle( $this );
4982                         $langObj = $contentHandler->getPageLanguage( $this );
4983                         $this->mPageLanguage = [ $langObj->getCode(), $wgLanguageCode ];
4984                 } else {
4985                         $langObj = wfGetLangObj( $this->mPageLanguage[0] );
4986                 }
4987
4988                 return $langObj;
4989         }
4990
4991         /**
4992          * Get the language in which the content of this page is written when
4993          * viewed by user. Defaults to $wgContLang, but in certain cases it can be
4994          * e.g. $wgLang (such as special pages, which are in the user language).
4995          *
4996          * @since 1.20
4997          * @return Language
4998          */
4999         public function getPageViewLanguage() {
5000                 global $wgLang;
5001
5002                 if ( $this->isSpecialPage() ) {
5003                         // If the user chooses a variant, the content is actually
5004                         // in a language whose code is the variant code.
5005                         $variant = $wgLang->getPreferredVariant();
5006                         if ( $wgLang->getCode() !== $variant ) {
5007                                 return Language::factory( $variant );
5008                         }
5009
5010                         return $wgLang;
5011                 }
5012
5013                 // Checking if DB language is set
5014                 $dbPageLanguage = $this->getDbPageLanguageCode();
5015                 if ( $dbPageLanguage ) {
5016                         $pageLang = wfGetLangObj( $dbPageLanguage );
5017                         $variant = $pageLang->getPreferredVariant();
5018                         if ( $pageLang->getCode() !== $variant ) {
5019                                 $pageLang = Language::factory( $variant );
5020                         }
5021
5022                         return $pageLang;
5023                 }
5024
5025                 // @note Can't be cached persistently, depends on user settings.
5026                 // @note ContentHandler::getPageViewLanguage() may need to load the
5027                 //   content to determine the page language!
5028                 $contentHandler = ContentHandler::getForTitle( $this );
5029                 $pageLang = $contentHandler->getPageViewLanguage( $this );
5030                 return $pageLang;
5031         }
5032
5033         /**
5034          * Get a list of rendered edit notices for this page.
5035          *
5036          * Array is keyed by the original message key, and values are rendered using parseAsBlock, so
5037          * they will already be wrapped in paragraphs.
5038          *
5039          * @since 1.21
5040          * @param int $oldid Revision ID that's being edited
5041          * @return array
5042          */
5043         public function getEditNotices( $oldid = 0 ) {
5044                 $notices = [];
5045
5046                 // Optional notice for the entire namespace
5047                 $editnotice_ns = 'editnotice-' . $this->getNamespace();
5048                 $msg = wfMessage( $editnotice_ns );
5049                 if ( $msg->exists() ) {
5050                         $html = $msg->parseAsBlock();
5051                         // Edit notices may have complex logic, but output nothing (T91715)
5052                         if ( trim( $html ) !== '' ) {
5053                                 $notices[$editnotice_ns] = Html::rawElement(
5054                                         'div',
5055                                         [ 'class' => [
5056                                                 'mw-editnotice',
5057                                                 'mw-editnotice-namespace',
5058                                                 Sanitizer::escapeClass( "mw-$editnotice_ns" )
5059                                         ] ],
5060                                         $html
5061                                 );
5062                         }
5063                 }
5064
5065                 if ( MWNamespace::hasSubpages( $this->getNamespace() ) ) {
5066                         // Optional notice for page itself and any parent page
5067                         $parts = explode( '/', $this->getDBkey() );
5068                         $editnotice_base = $editnotice_ns;
5069                         while ( count( $parts ) > 0 ) {
5070                                 $editnotice_base .= '-' . array_shift( $parts );
5071                                 $msg = wfMessage( $editnotice_base );
5072                                 if ( $msg->exists() ) {
5073                                         $html = $msg->parseAsBlock();
5074                                         if ( trim( $html ) !== '' ) {
5075                                                 $notices[$editnotice_base] = Html::rawElement(
5076                                                         'div',
5077                                                         [ 'class' => [
5078                                                                 'mw-editnotice',
5079                                                                 'mw-editnotice-base',
5080                                                                 Sanitizer::escapeClass( "mw-$editnotice_base" )
5081                                                         ] ],
5082                                                         $html
5083                                                 );
5084                                         }
5085                                 }
5086                         }
5087                 } else {
5088                         // Even if there are no subpages in namespace, we still don't want "/" in MediaWiki message keys
5089                         $editnoticeText = $editnotice_ns . '-' . strtr( $this->getDBkey(), '/', '-' );
5090                         $msg = wfMessage( $editnoticeText );
5091                         if ( $msg->exists() ) {
5092                                 $html = $msg->parseAsBlock();
5093                                 if ( trim( $html ) !== '' ) {
5094                                         $notices[$editnoticeText] = Html::rawElement(
5095                                                 'div',
5096                                                 [ 'class' => [
5097                                                         'mw-editnotice',
5098                                                         'mw-editnotice-page',
5099                                                         Sanitizer::escapeClass( "mw-$editnoticeText" )
5100                                                 ] ],
5101                                                 $html
5102                                         );
5103                                 }
5104                         }
5105                 }
5106
5107                 Hooks::run( 'TitleGetEditNotices', [ $this, $oldid, &$notices ] );
5108                 return $notices;
5109         }
5110
5111         /**
5112          * @return array
5113          */
5114         public function __sleep() {
5115                 return [
5116                         'mNamespace',
5117                         'mDbkeyform',
5118                         'mFragment',
5119                         'mInterwiki',
5120                         'mLocalInterwiki',
5121                         'mUserCaseDBKey',
5122                         'mDefaultNamespace',
5123                 ];
5124         }
5125
5126         public function __wakeup() {
5127                 $this->mArticleID = ( $this->mNamespace >= 0 ) ? -1 : 0;
5128                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
5129                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
5130         }
5131
5132 }