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                 return $a->getNamespace() <=> $b->getNamespace()
 788                         ?: strcmp( $a->getText(), $b->getText() );
 789         }
 790
 791         /**
 792          * Returns true if the title is valid, false if it is invalid.
 793          *
 794          * Valid titles can be round-tripped via makeTitleSafe() and newFromText().
 795          * Invalid titles may get returned from makeTitle(), and it may be useful to
 796          * allow them to exist, e.g. in order to process log entries about pages in
 797          * namespaces that belong to extensions that are no longer installed.
 798          *
 799          * @note This method is relatively expensive. When constructing Title
 800          * objects that need to be valid, use an instantiator method that is guaranteed
 801          * to return valid titles, such as makeTitleSafe() or newFromText().
 802          *
 803          * @return bool
 804          */
 805         public function isValid() {
 806                 $ns = $this->getNamespace();
 807
 808                 if ( !MWNamespace::exists( $ns ) ) {
 809                         return false;
 810                 }
 811
 812                 try {
 813                         $parser = MediaWikiServices::getInstance()->getTitleParser();
 814                         $parser->parseTitle( $this->getDBkey(), $ns );
 815                         return true;
 816                 } catch ( MalformedTitleException $ex ) {
 817                         return false;
 818                 }
 819         }
 820
 821         /**
 822          * Determine whether the object refers to a page within
 823          * this project (either this wiki or a wiki with a local
 824          * interwiki, see https://www.mediawiki.org/wiki/Manual:Interwiki_table#iw_local )
 825          *
 826          * @return bool True if this is an in-project interwiki link or a wikilink, false otherwise
 827          */
 828         public function isLocal() {
 829                 if ( $this->isExternal() ) {
 830                         $iw = self::getInterwikiLookup()->fetch( $this->mInterwiki );
 831                         if ( $iw ) {
 832                                 return $iw->isLocal();
 833                         }
 834                 }
 835                 return true;
 836         }
 837
 838         /**
 839          * Is this Title interwiki?
 840          *
 841          * @return bool
 842          */
 843         public function isExternal() {
 844                 return $this->mInterwiki !== '';
 845         }
 846
 847         /**
 848          * Get the interwiki prefix
 849          *
 850          * Use Title::isExternal to check if a interwiki is set
 851          *
 852          * @return string Interwiki prefix
 853          */
 854         public function getInterwiki() {
 855                 return $this->mInterwiki;
 856         }
 857
 858         /**
 859          * Was this a local interwiki link?
 860          *
 861          * @return bool
 862          */
 863         public function wasLocalInterwiki() {
 864                 return $this->mLocalInterwiki;
 865         }
 866
 867         /**
 868          * Determine whether the object refers to a page within
 869          * this project and is transcludable.
 870          *
 871          * @return bool True if this is transcludable
 872          */
 873         public function isTrans() {
 874                 if ( !$this->isExternal() ) {
 875                         return false;
 876                 }
 877
 878                 return self::getInterwikiLookup()->fetch( $this->mInterwiki )->isTranscludable();
 879         }
 880
 881         /**
 882          * Returns the DB name of the distant wiki which owns the object.
 883          *
 884          * @return string|false The DB name
 885          */
 886         public function getTransWikiID() {
 887                 if ( !$this->isExternal() ) {
 888                         return false;
 889                 }
 890
 891                 return self::getInterwikiLookup()->fetch( $this->mInterwiki )->getWikiID();
 892         }
 893
 894         /**
 895          * Get a TitleValue object representing this Title.
 896          *
 897          * @note Not all valid Titles have a corresponding valid TitleValue
 898          * (e.g. TitleValues cannot represent page-local links that have a
 899          * fragment but no title text).
 900          *
 901          * @return TitleValue|null
 902          */
 903         public function getTitleValue() {
 904                 if ( $this->mTitleValue === null ) {
 905                         try {
 906                                 $this->mTitleValue = new TitleValue(
 907                                         $this->getNamespace(),
 908                                         $this->getDBkey(),
 909                                         $this->getFragment(),
 910                                         $this->getInterwiki()
 911                                 );
 912                         } catch ( InvalidArgumentException $ex ) {
 913                                 wfDebug( __METHOD__ . ': Can\'t create a TitleValue for [[' .
 914                                         $this->getPrefixedText() . ']]: ' . $ex->getMessage() . "\n" );
 915                         }
 916                 }
 917
 918                 return $this->mTitleValue;
 919         }
 920
 921         /**
 922          * Get the text form (spaces not underscores) of the main part
 923          *
 924          * @return string Main part of the title
 925          */
 926         public function getText() {
 927                 return $this->mTextform;
 928         }
 929
 930         /**
 931          * Get the URL-encoded form of the main part
 932          *
 933          * @return string Main part of the title, URL-encoded
 934          */
 935         public function getPartialURL() {
 936                 return $this->mUrlform;
 937         }
 938
 939         /**
 940          * Get the main part with underscores
 941          *
 942          * @return string Main part of the title, with underscores
 943          */
 944         public function getDBkey() {
 945                 return $this->mDbkeyform;
 946         }
 947
 948         /**
 949          * Get the DB key with the initial letter case as specified by the user
 950          *
 951          * @return string DB key
 952          */
 953         function getUserCaseDBKey() {
 954                 if ( !is_null( $this->mUserCaseDBKey ) ) {
 955                         return $this->mUserCaseDBKey;
 956                 } else {
 957                         // If created via makeTitle(), $this->mUserCaseDBKey is not set.
 958                         return $this->mDbkeyform;
 959                 }
 960         }
 961
 962         /**
 963          * Get the namespace index, i.e. one of the NS_xxxx constants.
 964          *
 965          * @return int Namespace index
 966          */
 967         public function getNamespace() {
 968                 return $this->mNamespace;
 969         }
 970
 971         /**
 972          * Get the page's content model id, see the CONTENT_MODEL_XXX constants.
 973          *
 974          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
 975          * @return string Content model id
 976          */
 977         public function getContentModel( $flags = 0 ) {
 978                 if ( !$this->mForcedContentModel
 979                         && ( !$this->mContentModel || $flags === self::GAID_FOR_UPDATE )
 980                         && $this->getArticleID( $flags )
 981                 ) {
 982                         $linkCache = MediaWikiServices::getInstance()->getLinkCache();
 983                         $linkCache->addLinkObj( $this ); # in case we already had an article ID
 984                         $this->mContentModel = $linkCache->getGoodLinkFieldObj( $this, 'model' );
 985                 }
 986
 987                 if ( !$this->mContentModel ) {
 988                         $this->mContentModel = ContentHandler::getDefaultModelFor( $this );
 989                 }
 990
 991                 return $this->mContentModel;
 992         }
 993
 994         /**
 995          * Convenience method for checking a title's content model name
 996          *
 997          * @param string $id The content model ID (use the CONTENT_MODEL_XXX constants).
 998          * @return bool True if $this->getContentModel() == $id
 999          */
1000         public function hasContentModel( $id ) {
1001                 return $this->getContentModel() == $id;
1002         }
1003
1004         /**
1005          * Set a proposed content model for the page for permissions
1006          * checking. This does not actually change the content model
1007          * of a title!
1008          *
1009          * Additionally, you should make sure you've checked
1010          * ContentHandler::canBeUsedOn() first.
1011          *
1012          * @since 1.28
1013          * @param string $model CONTENT_MODEL_XXX constant
1014          */
1015         public function setContentModel( $model ) {
1016                 $this->mContentModel = $model;
1017                 $this->mForcedContentModel = true;
1018         }
1019
1020         /**
1021          * Get the namespace text
1022          *
1023          * @return string|false Namespace text
1024          */
1025         public function getNsText() {
1026                 if ( $this->isExternal() ) {
1027                         // This probably shouldn't even happen, except for interwiki transclusion.
1028                         // If possible, use the canonical name for the foreign namespace.
1029                         $nsText = MWNamespace::getCanonicalName( $this->mNamespace );
1030                         if ( $nsText !== false ) {
1031                                 return $nsText;
1032                         }
1033                 }
1034
1035                 try {
1036                         $formatter = self::getTitleFormatter();
1037                         return $formatter->getNamespaceName( $this->mNamespace, $this->mDbkeyform );
1038                 } catch ( InvalidArgumentException $ex ) {
1039                         wfDebug( __METHOD__ . ': ' . $ex->getMessage() . "\n" );
1040                         return false;
1041                 }
1042         }
1043
1044         /**
1045          * Get the namespace text of the subject (rather than talk) page
1046          *
1047          * @return string Namespace text
1048          */
1049         public function getSubjectNsText() {
1050                 global $wgContLang;
1051                 return $wgContLang->getNsText( MWNamespace::getSubject( $this->mNamespace ) );
1052         }
1053
1054         /**
1055          * Get the namespace text of the talk page
1056          *
1057          * @return string Namespace text
1058          */
1059         public function getTalkNsText() {
1060                 global $wgContLang;
1061                 return $wgContLang->getNsText( MWNamespace::getTalk( $this->mNamespace ) );
1062         }
1063
1064         /**
1065          * Can this title have a corresponding talk page?
1066          *
1067          * @deprecated since 1.30, use canHaveTalkPage() instead.
1068          *
1069          * @return bool True if this title either is a talk page or can have a talk page associated.
1070          */
1071         public function canTalk() {
1072                 return $this->canHaveTalkPage();
1073         }
1074
1075         /**
1076          * Can this title have a corresponding talk page?
1077          *
1078          * @see MWNamespace::hasTalkNamespace
1079          * @since 1.30
1080          *
1081          * @return bool True if this title either is a talk page or can have a talk page associated.
1082          */
1083         public function canHaveTalkPage() {
1084                 return MWNamespace::hasTalkNamespace( $this->mNamespace );
1085         }
1086
1087         /**
1088          * Is this in a namespace that allows actual pages?
1089          *
1090          * @return bool
1091          */
1092         public function canExist() {
1093                 return $this->mNamespace >= NS_MAIN;
1094         }
1095
1096         /**
1097          * Can this title be added to a user's watchlist?
1098          *
1099          * @return bool
1100          */
1101         public function isWatchable() {
1102                 return !$this->isExternal() && MWNamespace::isWatchable( $this->getNamespace() );
1103         }
1104
1105         /**
1106          * Returns true if this is a special page.
1107          *
1108          * @return bool
1109          */
1110         public function isSpecialPage() {
1111                 return $this->getNamespace() == NS_SPECIAL;
1112         }
1113
1114         /**
1115          * Returns true if this title resolves to the named special page
1116          *
1117          * @param string $name The special page name
1118          * @return bool
1119          */
1120         public function isSpecial( $name ) {
1121                 if ( $this->isSpecialPage() ) {
1122                         list( $thisName, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $this->getDBkey() );
1123                         if ( $name == $thisName ) {
1124                                 return true;
1125                         }
1126                 }
1127                 return false;
1128         }
1129
1130         /**
1131          * If the Title refers to a special page alias which is not the local default, resolve
1132          * the alias, and localise the name as necessary.  Otherwise, return $this
1133          *
1134          * @return Title
1135          */
1136         public function fixSpecialName() {
1137                 if ( $this->isSpecialPage() ) {
1138                         list( $canonicalName, $par ) = SpecialPageFactory::resolveAlias( $this->mDbkeyform );
1139                         if ( $canonicalName ) {
1140                                 $localName = SpecialPageFactory::getLocalNameFor( $canonicalName, $par );
1141                                 if ( $localName != $this->mDbkeyform ) {
1142                                         return self::makeTitle( NS_SPECIAL, $localName );
1143                                 }
1144                         }
1145                 }
1146                 return $this;
1147         }
1148
1149         /**
1150          * Returns true if the title is inside the specified namespace.
1151          *
1152          * Please make use of this instead of comparing to getNamespace()
1153          * This function is much more resistant to changes we may make
1154          * to namespaces than code that makes direct comparisons.
1155          * @param int $ns The namespace
1156          * @return bool
1157          * @since 1.19
1158          */
1159         public function inNamespace( $ns ) {
1160                 return MWNamespace::equals( $this->getNamespace(), $ns );
1161         }
1162
1163         /**
1164          * Returns true if the title is inside one of the specified namespaces.
1165          *
1166          * @param int|int[] $namespaces,... The namespaces to check for
1167          * @return bool
1168          * @since 1.19
1169          */
1170         public function inNamespaces( /* ... */ ) {
1171                 $namespaces = func_get_args();
1172                 if ( count( $namespaces ) > 0 && is_array( $namespaces[0] ) ) {
1173                         $namespaces = $namespaces[0];
1174                 }
1175
1176                 foreach ( $namespaces as $ns ) {
1177                         if ( $this->inNamespace( $ns ) ) {
1178                                 return true;
1179                         }
1180                 }
1181
1182                 return false;
1183         }
1184
1185         /**
1186          * Returns true if the title has the same subject namespace as the
1187          * namespace specified.
1188          * For example this method will take NS_USER and return true if namespace
1189          * is either NS_USER or NS_USER_TALK since both of them have NS_USER
1190          * as their subject namespace.
1191          *
1192          * This is MUCH simpler than individually testing for equivalence
1193          * against both NS_USER and NS_USER_TALK, and is also forward compatible.
1194          * @since 1.19
1195          * @param int $ns
1196          * @return bool
1197          */
1198         public function hasSubjectNamespace( $ns ) {
1199                 return MWNamespace::subjectEquals( $this->getNamespace(), $ns );
1200         }
1201
1202         /**
1203          * Is this Title in a namespace which contains content?
1204          * In other words, is this a content page, for the purposes of calculating
1205          * statistics, etc?
1206          *
1207          * @return bool
1208          */
1209         public function isContentPage() {
1210                 return MWNamespace::isContent( $this->getNamespace() );
1211         }
1212
1213         /**
1214          * Would anybody with sufficient privileges be able to move this page?
1215          * Some pages just aren't movable.
1216          *
1217          * @return bool
1218          */
1219         public function isMovable() {
1220                 if ( !MWNamespace::isMovable( $this->getNamespace() ) || $this->isExternal() ) {
1221                         // Interwiki title or immovable namespace. Hooks don't get to override here
1222                         return false;
1223                 }
1224
1225                 $result = true;
1226                 Hooks::run( 'TitleIsMovable', [ $this, &$result ] );
1227                 return $result;
1228         }
1229
1230         /**
1231          * Is this the mainpage?
1232          * @note Title::newFromText seems to be sufficiently optimized by the title
1233          * cache that we don't need to over-optimize by doing direct comparisons and
1234          * accidentally creating new bugs where $title->equals( Title::newFromText() )
1235          * ends up reporting something differently than $title->isMainPage();
1236          *
1237          * @since 1.18
1238          * @return bool
1239          */
1240         public function isMainPage() {
1241                 return $this->equals( self::newMainPage() );
1242         }
1243
1244         /**
1245          * Is this a subpage?
1246          *
1247          * @return bool
1248          */
1249         public function isSubpage() {
1250                 return MWNamespace::hasSubpages( $this->mNamespace )
1251                         ? strpos( $this->getText(), '/' ) !== false
1252                         : false;
1253         }
1254
1255         /**
1256          * Is this a conversion table for the LanguageConverter?
1257          *
1258          * @return bool
1259          */
1260         public function isConversionTable() {
1261                 // @todo ConversionTable should become a separate content model.
1262
1263                 return $this->getNamespace() == NS_MEDIAWIKI &&
1264                         strpos( $this->getText(), 'Conversiontable/' ) === 0;
1265         }
1266
1267         /**
1268          * Does that page contain wikitext, or it is JS, CSS or whatever?
1269          *
1270          * @return bool
1271          */
1272         public function isWikitextPage() {
1273                 return $this->hasContentModel( CONTENT_MODEL_WIKITEXT );
1274         }
1275
1276         /**
1277          * Could this MediaWiki namespace page contain custom CSS, JSON, or JavaScript for the
1278          * global UI. This is generally true for pages in the MediaWiki namespace having
1279          * CONTENT_MODEL_CSS, CONTENT_MODEL_JSON, or CONTENT_MODEL_JAVASCRIPT.
1280          *
1281          * This method does *not* return true for per-user JS/JSON/CSS. Use isUserConfigPage()
1282          * for that!
1283          *
1284          * Note that this method should not return true for pages that contain and show
1285          * "inactive" CSS, JSON, or JS.
1286          *
1287          * @return bool
1288          * @since 1.31
1289          */
1290         public function isSiteConfigPage() {
1291                 return (
1292                         NS_MEDIAWIKI == $this->mNamespace
1293                         && (
1294                                 $this->hasContentModel( CONTENT_MODEL_CSS )
1295                                 || $this->hasContentModel( CONTENT_MODEL_JSON )
1296                                 || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT )
1297                         )
1298                 );
1299         }
1300
1301         /**
1302          * @return bool
1303          * @deprecated Since 1.31; use ::isSiteConfigPage() instead (which also checks for JSON pages)
1304          */
1305         public function isCssOrJsPage() {
1306                 wfDeprecated( __METHOD__, '1.31' );
1307                 return ( NS_MEDIAWIKI == $this->mNamespace
1308                                 && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1309                                         || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) ) );
1310         }
1311
1312         /**
1313          * Is this a "config" (.css, .json, or .js) sub-page of a user page?
1314          *
1315          * @return bool
1316          * @since 1.31
1317          */
1318         public function isUserConfigPage() {
1319                 return (
1320                         NS_USER == $this->mNamespace
1321                         && $this->isSubpage()
1322                         && (
1323                                 $this->hasContentModel( CONTENT_MODEL_CSS )
1324                                 || $this->hasContentModel( CONTENT_MODEL_JSON )
1325                                 || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT )
1326                         )
1327                 );
1328         }
1329
1330         /**
1331          * @return bool
1332          * @deprecated Since 1.31; use ::isUserConfigPage() instead (which also checks for JSON pages)
1333          */
1334         public function isCssJsSubpage() {
1335                 wfDeprecated( __METHOD__, '1.31' );
1336                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1337                                 && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1338                                         || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) ) );
1339         }
1340
1341         /**
1342          * Trim down a .css, .json, or .js subpage title to get the corresponding skin name
1343          *
1344          * @return string Containing skin name from .css, .json, or .js subpage title
1345          * @since 1.31
1346          */
1347         public function getSkinFromConfigSubpage() {
1348                 $subpage = explode( '/', $this->mTextform );
1349                 $subpage = $subpage[count( $subpage ) - 1];
1350                 $lastdot = strrpos( $subpage, '.' );
1351                 if ( $lastdot === false ) {
1352                         return $subpage; # Never happens: only called for names ending in '.css'/'.json'/'.js'
1353                 }
1354                 return substr( $subpage, 0, $lastdot );
1355         }
1356
1357         /**
1358          * @deprecated Since 1.31; use ::getSkinFromConfigSubpage() instead
1359          * @return string Containing skin name from .css, .json, or .js subpage title
1360          */
1361         public function getSkinFromCssJsSubpage() {
1362                 wfDeprecated( __METHOD__, '1.31' );
1363                 return $this->getSkinFromConfigSubpage();
1364         }
1365
1366         /**
1367          * Is this a CSS "config" sub-page of a user page?
1368          *
1369          * @return bool
1370          * @since 1.31
1371          */
1372         public function isUserCssConfigPage() {
1373                 return (
1374                         NS_USER == $this->mNamespace
1375                         && $this->isSubpage()
1376                         && $this->hasContentModel( CONTENT_MODEL_CSS )
1377                 );
1378         }
1379
1380         /**
1381          * @deprecated Since 1.31; use ::isUserCssConfigPage()
1382          * @return bool
1383          */
1384         public function isCssSubpage() {
1385                 wfDeprecated( __METHOD__, '1.31' );
1386                 return $this->isUserCssConfigPage();
1387         }
1388
1389         /**
1390          * Is this a JSON "config" sub-page of a user page?
1391          *
1392          * @return bool
1393          * @since 1.31
1394          */
1395         public function isUserJsonConfigPage() {
1396                 return (
1397                         NS_USER == $this->mNamespace
1398                         && $this->isSubpage()
1399                         && $this->hasContentModel( CONTENT_MODEL_JSON )
1400                 );
1401         }
1402
1403         /**
1404          * Is this a JS "config" sub-page of a user page?
1405          *
1406          * @return bool
1407          * @since 1.31
1408          */
1409         public function isUserJsConfigPage() {
1410                 return (
1411                         NS_USER == $this->mNamespace
1412                         && $this->isSubpage()
1413                         && $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT )
1414                 );
1415         }
1416
1417         /**
1418          * @deprecated Since 1.31; use ::isUserJsConfigPage()
1419          * @return bool
1420          */
1421         public function isJsSubpage() {
1422                 wfDeprecated( __METHOD__, '1.31' );
1423                 return $this->isUserJsConfigPage();
1424         }
1425
1426         /**
1427          * Is this a talk page of some sort?
1428          *
1429          * @return bool
1430          */
1431         public function isTalkPage() {
1432                 return MWNamespace::isTalk( $this->getNamespace() );
1433         }
1434
1435         /**
1436          * Get a Title object associated with the talk page of this article
1437          *
1438          * @return Title The object for the talk page
1439          */
1440         public function getTalkPage() {
1441                 return self::makeTitle( MWNamespace::getTalk( $this->getNamespace() ), $this->getDBkey() );
1442         }
1443
1444         /**
1445          * Get a Title object associated with the talk page of this article,
1446          * if such a talk page can exist.
1447          *
1448          * @since 1.30
1449          *
1450          * @return Title|null The object for the talk page,
1451          *         or null if no associated talk page can exist, according to canHaveTalkPage().
1452          */
1453         public function getTalkPageIfDefined() {
1454                 if ( !$this->canHaveTalkPage() ) {
1455                         return null;
1456                 }
1457
1458                 return $this->getTalkPage();
1459         }
1460
1461         /**
1462          * Get a title object associated with the subject page of this
1463          * talk page
1464          *
1465          * @return Title The object for the subject page
1466          */
1467         public function getSubjectPage() {
1468                 // Is this the same title?
1469                 $subjectNS = MWNamespace::getSubject( $this->getNamespace() );
1470                 if ( $this->getNamespace() == $subjectNS ) {
1471                         return $this;
1472                 }
1473                 return self::makeTitle( $subjectNS, $this->getDBkey() );
1474         }
1475
1476         /**
1477          * Get the other title for this page, if this is a subject page
1478          * get the talk page, if it is a subject page get the talk page
1479          *
1480          * @since 1.25
1481          * @throws MWException If the page doesn't have an other page
1482          * @return Title
1483          */
1484         public function getOtherPage() {
1485                 if ( $this->isSpecialPage() ) {
1486                         throw new MWException( 'Special pages cannot have other pages' );
1487                 }
1488                 if ( $this->isTalkPage() ) {
1489                         return $this->getSubjectPage();
1490                 } else {
1491                         if ( !$this->canHaveTalkPage() ) {
1492                                 throw new MWException( "{$this->getPrefixedText()} does not have an other page" );
1493                         }
1494                         return $this->getTalkPage();
1495                 }
1496         }
1497
1498         /**
1499          * Get the default namespace index, for when there is no namespace
1500          *
1501          * @return int Default namespace index
1502          */
1503         public function getDefaultNamespace() {
1504                 return $this->mDefaultNamespace;
1505         }
1506
1507         /**
1508          * Get the Title fragment (i.e.\ the bit after the #) in text form
1509          *
1510          * Use Title::hasFragment to check for a fragment
1511          *
1512          * @return string Title fragment
1513          */
1514         public function getFragment() {
1515                 return $this->mFragment;
1516         }
1517
1518         /**
1519          * Check if a Title fragment is set
1520          *
1521          * @return bool
1522          * @since 1.23
1523          */
1524         public function hasFragment() {
1525                 return $this->mFragment !== '';
1526         }
1527
1528         /**
1529          * Get the fragment in URL form, including the "#" character if there is one
1530          *
1531          * @return string Fragment in URL form
1532          */
1533         public function getFragmentForURL() {
1534                 if ( !$this->hasFragment() ) {
1535                         return '';
1536                 } elseif ( $this->isExternal()
1537                         && !self::getInterwikiLookup()->fetch( $this->mInterwiki )->isLocal()
1538                 ) {
1539                         return '#' . Sanitizer::escapeIdForExternalInterwiki( $this->getFragment() );
1540                 }
1541                 return '#' . Sanitizer::escapeIdForLink( $this->getFragment() );
1542         }
1543
1544         /**
1545          * Set the fragment for this title. Removes the first character from the
1546          * specified fragment before setting, so it assumes you're passing it with
1547          * an initial "#".
1548          *
1549          * Deprecated for public use, use Title::makeTitle() with fragment parameter,
1550          * or Title::createFragmentTarget().
1551          * Still in active use privately.
1552          *
1553          * @private
1554          * @param string $fragment Text
1555          */
1556         public function setFragment( $fragment ) {
1557                 $this->mFragment = strtr( substr( $fragment, 1 ), '_', ' ' );
1558         }
1559
1560         /**
1561          * Creates a new Title for a different fragment of the same page.
1562          *
1563          * @since 1.27
1564          * @param string $fragment
1565          * @return Title
1566          */
1567         public function createFragmentTarget( $fragment ) {
1568                 return self::makeTitle(
1569                         $this->getNamespace(),
1570                         $this->getText(),
1571                         $fragment,
1572                         $this->getInterwiki()
1573                 );
1574         }
1575
1576         /**
1577          * Prefix some arbitrary text with the namespace or interwiki prefix
1578          * of this object
1579          *
1580          * @param string $name The text
1581          * @return string The prefixed text
1582          */
1583         private function prefix( $name ) {
1584                 global $wgContLang;
1585
1586                 $p = '';
1587                 if ( $this->isExternal() ) {
1588                         $p = $this->mInterwiki . ':';
1589                 }
1590
1591                 if ( 0 != $this->mNamespace ) {
1592                         $nsText = $this->getNsText();
1593
1594                         if ( $nsText === false ) {
1595                                 // See T165149. Awkward, but better than erroneously linking to the main namespace.
1596                                 $nsText = $wgContLang->getNsText( NS_SPECIAL ) . ":Badtitle/NS{$this->mNamespace}";
1597                         }
1598
1599                         $p .= $nsText . ':';
1600                 }
1601                 return $p . $name;
1602         }
1603
1604         /**
1605          * Get the prefixed database key form
1606          *
1607          * @return string The prefixed title, with underscores and
1608          *  any interwiki and namespace prefixes
1609          */
1610         public function getPrefixedDBkey() {
1611                 $s = $this->prefix( $this->mDbkeyform );
1612                 $s = strtr( $s, ' ', '_' );
1613                 return $s;
1614         }
1615
1616         /**
1617          * Get the prefixed title with spaces.
1618          * This is the form usually used for display
1619          *
1620          * @return string The prefixed title, with spaces
1621          */
1622         public function getPrefixedText() {
1623                 if ( $this->mPrefixedText === null ) {
1624                         $s = $this->prefix( $this->mTextform );
1625                         $s = strtr( $s, '_', ' ' );
1626                         $this->mPrefixedText = $s;
1627                 }
1628                 return $this->mPrefixedText;
1629         }
1630
1631         /**
1632          * Return a string representation of this title
1633          *
1634          * @return string Representation of this title
1635          */
1636         public function __toString() {
1637                 return $this->getPrefixedText();
1638         }
1639
1640         /**
1641          * Get the prefixed title with spaces, plus any fragment
1642          * (part beginning with '#')
1643          *
1644          * @return string The prefixed title, with spaces and the fragment, including '#'
1645          */
1646         public function getFullText() {
1647                 $text = $this->getPrefixedText();
1648                 if ( $this->hasFragment() ) {
1649                         $text .= '#' . $this->getFragment();
1650                 }
1651                 return $text;
1652         }
1653
1654         /**
1655          * Get the root page name text without a namespace, i.e. the leftmost part before any slashes
1656          *
1657          * @par Example:
1658          * @code
1659          * Title::newFromText('User:Foo/Bar/Baz')->getRootText();
1660          * # returns: 'Foo'
1661          * @endcode
1662          *
1663          * @return string Root name
1664          * @since 1.20
1665          */
1666         public function getRootText() {
1667                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1668                         return $this->getText();
1669                 }
1670
1671                 return strtok( $this->getText(), '/' );
1672         }
1673
1674         /**
1675          * Get the root page name title, i.e. the leftmost part before any slashes
1676          *
1677          * @par Example:
1678          * @code
1679          * Title::newFromText('User:Foo/Bar/Baz')->getRootTitle();
1680          * # returns: Title{User:Foo}
1681          * @endcode
1682          *
1683          * @return Title Root title
1684          * @since 1.20
1685          */
1686         public function getRootTitle() {
1687                 return self::makeTitle( $this->getNamespace(), $this->getRootText() );
1688         }
1689
1690         /**
1691          * Get the base page name without a namespace, i.e. the part before the subpage name
1692          *
1693          * @par Example:
1694          * @code
1695          * Title::newFromText('User:Foo/Bar/Baz')->getBaseText();
1696          * # returns: 'Foo/Bar'
1697          * @endcode
1698          *
1699          * @return string Base name
1700          */
1701         public function getBaseText() {
1702                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1703                         return $this->getText();
1704                 }
1705
1706                 $parts = explode( '/', $this->getText() );
1707                 # Don't discard the real title if there's no subpage involved
1708                 if ( count( $parts ) > 1 ) {
1709                         unset( $parts[count( $parts ) - 1] );
1710                 }
1711                 return implode( '/', $parts );
1712         }
1713
1714         /**
1715          * Get the base page name title, i.e. the part before the subpage name
1716          *
1717          * @par Example:
1718          * @code
1719          * Title::newFromText('User:Foo/Bar/Baz')->getBaseTitle();
1720          * # returns: Title{User:Foo/Bar}
1721          * @endcode
1722          *
1723          * @return Title Base title
1724          * @since 1.20
1725          */
1726         public function getBaseTitle() {
1727                 return self::makeTitle( $this->getNamespace(), $this->getBaseText() );
1728         }
1729
1730         /**
1731          * Get the lowest-level subpage name, i.e. the rightmost part after any slashes
1732          *
1733          * @par Example:
1734          * @code
1735          * Title::newFromText('User:Foo/Bar/Baz')->getSubpageText();
1736          * # returns: "Baz"
1737          * @endcode
1738          *
1739          * @return string Subpage name
1740          */
1741         public function getSubpageText() {
1742                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1743                         return $this->mTextform;
1744                 }
1745                 $parts = explode( '/', $this->mTextform );
1746                 return $parts[count( $parts ) - 1];
1747         }
1748
1749         /**
1750          * Get the title for a subpage of the current page
1751          *
1752          * @par Example:
1753          * @code
1754          * Title::newFromText('User:Foo/Bar/Baz')->getSubpage("Asdf");
1755          * # returns: Title{User:Foo/Bar/Baz/Asdf}
1756          * @endcode
1757          *
1758          * @param string $text The subpage name to add to the title
1759          * @return Title Subpage title
1760          * @since 1.20
1761          */
1762         public function getSubpage( $text ) {
1763                 return self::makeTitleSafe( $this->getNamespace(), $this->getText() . '/' . $text );
1764         }
1765
1766         /**
1767          * Get a URL-encoded form of the subpage text
1768          *
1769          * @return string URL-encoded subpage name
1770          */
1771         public function getSubpageUrlForm() {
1772                 $text = $this->getSubpageText();
1773                 $text = wfUrlencode( strtr( $text, ' ', '_' ) );
1774                 return $text;
1775         }
1776
1777         /**
1778          * Get a URL-encoded title (not an actual URL) including interwiki
1779          *
1780          * @return string The URL-encoded form
1781          */
1782         public function getPrefixedURL() {
1783                 $s = $this->prefix( $this->mDbkeyform );
1784                 $s = wfUrlencode( strtr( $s, ' ', '_' ) );
1785                 return $s;
1786         }
1787
1788         /**
1789          * Helper to fix up the get{Canonical,Full,Link,Local,Internal}URL args
1790          * get{Canonical,Full,Link,Local,Internal}URL methods accepted an optional
1791          * second argument named variant. This was deprecated in favor
1792          * of passing an array of option with a "variant" key
1793          * Once $query2 is removed for good, this helper can be dropped
1794          * and the wfArrayToCgi moved to getLocalURL();
1795          *
1796          * @since 1.19 (r105919)
1797          * @param array|string $query
1798          * @param string|string[]|bool $query2
1799          * @return string
1800          */
1801         private static function fixUrlQueryArgs( $query, $query2 = false ) {
1802                 if ( $query2 !== false ) {
1803                         wfDeprecated( "Title::get{Canonical,Full,Link,Local,Internal}URL " .
1804                                 "method called with a second parameter is deprecated. Add your " .
1805                                 "parameter to an array passed as the first parameter.", "1.19" );
1806                 }
1807                 if ( is_array( $query ) ) {
1808                         $query = wfArrayToCgi( $query );
1809                 }
1810                 if ( $query2 ) {
1811                         if ( is_string( $query2 ) ) {
1812                                 // $query2 is a string, we will consider this to be
1813                                 // a deprecated $variant argument and add it to the query
1814                                 $query2 = wfArrayToCgi( [ 'variant' => $query2 ] );
1815                         } else {
1816                                 $query2 = wfArrayToCgi( $query2 );
1817                         }
1818                         // If we have $query content add a & to it first
1819                         if ( $query ) {
1820                                 $query .= '&';
1821                         }
1822                         // Now append the queries together
1823                         $query .= $query2;
1824                 }
1825                 return $query;
1826         }
1827
1828         /**
1829          * Get a real URL referring to this title, with interwiki link and
1830          * fragment
1831          *
1832          * @see self::getLocalURL for the arguments.
1833          * @see wfExpandUrl
1834          * @param string|string[] $query
1835          * @param string|string[]|bool $query2
1836          * @param string|int|null $proto Protocol type to use in URL
1837          * @return string The URL
1838          */
1839         public function getFullURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1840                 $query = self::fixUrlQueryArgs( $query, $query2 );
1841
1842                 # Hand off all the decisions on urls to getLocalURL
1843                 $url = $this->getLocalURL( $query );
1844
1845                 # Expand the url to make it a full url. Note that getLocalURL has the
1846                 # potential to output full urls for a variety of reasons, so we use
1847                 # wfExpandUrl instead of simply prepending $wgServer
1848                 $url = wfExpandUrl( $url, $proto );
1849
1850                 # Finally, add the fragment.
1851                 $url .= $this->getFragmentForURL();
1852                 // Avoid PHP 7.1 warning from passing $this by reference
1853                 $titleRef = $this;
1854                 Hooks::run( 'GetFullURL', [ &$titleRef, &$url, $query ] );
1855                 return $url;
1856         }
1857
1858         /**
1859          * Get a url appropriate for making redirects based on an untrusted url arg
1860          *
1861          * This is basically the same as getFullUrl(), but in the case of external
1862          * interwikis, we send the user to a landing page, to prevent possible
1863          * phishing attacks and the like.
1864          *
1865          * @note Uses current protocol by default, since technically relative urls
1866          *   aren't allowed in redirects per HTTP spec, so this is not suitable for
1867          *   places where the url gets cached, as might pollute between
1868          *   https and non-https users.
1869          * @see self::getLocalURL for the arguments.
1870          * @param array|string $query
1871          * @param string $proto Protocol type to use in URL
1872          * @return string A url suitable to use in an HTTP location header.
1873          */
1874         public function getFullUrlForRedirect( $query = '', $proto = PROTO_CURRENT ) {
1875                 $target = $this;
1876                 if ( $this->isExternal() ) {
1877                         $target = SpecialPage::getTitleFor(
1878                                 'GoToInterwiki',
1879                                 $this->getPrefixedDBkey()
1880                         );
1881                 }
1882                 return $target->getFullURL( $query, false, $proto );
1883         }
1884
1885         /**
1886          * Get a URL with no fragment or server name (relative URL) from a Title object.
1887          * If this page is generated with action=render, however,
1888          * $wgServer is prepended to make an absolute URL.
1889          *
1890          * @see self::getFullURL to always get an absolute URL.
1891          * @see self::getLinkURL to always get a URL that's the simplest URL that will be
1892          *  valid to link, locally, to the current Title.
1893          * @see self::newFromText to produce a Title object.
1894          *
1895          * @param string|string[] $query An optional query string,
1896          *   not used for interwiki links. Can be specified as an associative array as well,
1897          *   e.g., array( 'action' => 'edit' ) (keys and values will be URL-escaped).
1898          *   Some query patterns will trigger various shorturl path replacements.
1899          * @param string|string[]|bool $query2 An optional secondary query array. This one MUST
1900          *   be an array. If a string is passed it will be interpreted as a deprecated
1901          *   variant argument and urlencoded into a variant= argument.
1902          *   This second query argument will be added to the $query
1903          *   The second parameter is deprecated since 1.19. Pass it as a key,value
1904          *   pair in the first parameter array instead.
1905          *
1906          * @return string String of the URL.
1907          */
1908         public function getLocalURL( $query = '', $query2 = false ) {
1909                 global $wgArticlePath, $wgScript, $wgServer, $wgRequest;
1910
1911                 $query = self::fixUrlQueryArgs( $query, $query2 );
1912
1913                 $interwiki = self::getInterwikiLookup()->fetch( $this->mInterwiki );
1914                 if ( $interwiki ) {
1915                         $namespace = $this->getNsText();
1916                         if ( $namespace != '' ) {
1917                                 # Can this actually happen? Interwikis shouldn't be parsed.
1918                                 # Yes! It can in interwiki transclusion. But... it probably shouldn't.
1919                                 $namespace .= ':';
1920                         }
1921                         $url = $interwiki->getURL( $namespace . $this->getDBkey() );
1922                         $url = wfAppendQuery( $url, $query );
1923                 } else {
1924                         $dbkey = wfUrlencode( $this->getPrefixedDBkey() );
1925                         if ( $query == '' ) {
1926                                 $url = str_replace( '$1', $dbkey, $wgArticlePath );
1927                                 // Avoid PHP 7.1 warning from passing $this by reference
1928                                 $titleRef = $this;
1929                                 Hooks::run( 'GetLocalURL::Article', [ &$titleRef, &$url ] );
1930                         } else {
1931                                 global $wgVariantArticlePath, $wgActionPaths, $wgContLang;
1932                                 $url = false;
1933                                 $matches = [];
1934
1935                                 if ( !empty( $wgActionPaths )
1936                                         && preg_match( '/^(.*&|)action=([^&]*)(&(.*)|)$/', $query, $matches )
1937                                 ) {
1938                                         $action = urldecode( $matches[2] );
1939                                         if ( isset( $wgActionPaths[$action] ) ) {
1940                                                 $query = $matches[1];
1941                                                 if ( isset( $matches[4] ) ) {
1942                                                         $query .= $matches[4];
1943                                                 }
1944                                                 $url = str_replace( '$1', $dbkey, $wgActionPaths[$action] );
1945                                                 if ( $query != '' ) {
1946                                                         $url = wfAppendQuery( $url, $query );
1947                                                 }
1948                                         }
1949                                 }
1950
1951                                 if ( $url === false
1952                                         && $wgVariantArticlePath
1953                                         && preg_match( '/^variant=([^&]*)$/', $query, $matches )
1954                                         && $this->getPageLanguage()->equals( $wgContLang )
1955                                         && $this->getPageLanguage()->hasVariants()
1956                                 ) {
1957                                         $variant = urldecode( $matches[1] );
1958                                         if ( $this->getPageLanguage()->hasVariant( $variant ) ) {
1959                                                 // Only do the variant replacement if the given variant is a valid
1960                                                 // variant for the page's language.
1961                                                 $url = str_replace( '$2', urlencode( $variant ), $wgVariantArticlePath );
1962                                                 $url = str_replace( '$1', $dbkey, $url );
1963                                         }
1964                                 }
1965
1966                                 if ( $url === false ) {
1967                                         if ( $query == '-' ) {
1968                                                 $query = '';
1969                                         }
1970                                         $url = "{$wgScript}?title={$dbkey}&{$query}";
1971                                 }
1972                         }
1973                         // Avoid PHP 7.1 warning from passing $this by reference
1974                         $titleRef = $this;
1975                         Hooks::run( 'GetLocalURL::Internal', [ &$titleRef, &$url, $query ] );
1976
1977                         // @todo FIXME: This causes breakage in various places when we
1978                         // actually expected a local URL and end up with dupe prefixes.
1979                         if ( $wgRequest->getVal( 'action' ) == 'render' ) {
1980                                 $url = $wgServer . $url;
1981                         }
1982                 }
1983                 // Avoid PHP 7.1 warning from passing $this by reference
1984                 $titleRef = $this;
1985                 Hooks::run( 'GetLocalURL', [ &$titleRef, &$url, $query ] );
1986                 return $url;
1987         }
1988
1989         /**
1990          * Get a URL that's the simplest URL that will be valid to link, locally,
1991          * to the current Title.  It includes the fragment, but does not include
1992          * the server unless action=render is used (or the link is external).  If
1993          * there's a fragment but the prefixed text is empty, we just return a link
1994          * to the fragment.
1995          *
1996          * The result obviously should not be URL-escaped, but does need to be
1997          * HTML-escaped if it's being output in HTML.
1998          *
1999          * @param string|string[] $query
2000          * @param bool $query2
2001          * @param string|int|bool $proto A PROTO_* constant on how the URL should be expanded,
2002          *                               or false (default) for no expansion
2003          * @see self::getLocalURL for the arguments.
2004          * @return string The URL
2005          */
2006         public function getLinkURL( $query = '', $query2 = false, $proto = false ) {
2007                 if ( $this->isExternal() || $proto !== false ) {
2008                         $ret = $this->getFullURL( $query, $query2, $proto );
2009                 } elseif ( $this->getPrefixedText() === '' && $this->hasFragment() ) {
2010                         $ret = $this->getFragmentForURL();
2011                 } else {
2012                         $ret = $this->getLocalURL( $query, $query2 ) . $this->getFragmentForURL();
2013                 }
2014                 return $ret;
2015         }
2016
2017         /**
2018          * Get the URL form for an internal link.
2019          * - Used in various CDN-related code, in case we have a different
2020          * internal hostname for the server from the exposed one.
2021          *
2022          * This uses $wgInternalServer to qualify the path, or $wgServer
2023          * if $wgInternalServer is not set. If the server variable used is
2024          * protocol-relative, the URL will be expanded to http://
2025          *
2026          * @see self::getLocalURL for the arguments.
2027          * @param string $query
2028          * @param string|bool $query2
2029          * @return string The URL
2030          */
2031         public function getInternalURL( $query = '', $query2 = false ) {
2032                 global $wgInternalServer, $wgServer;
2033                 $query = self::fixUrlQueryArgs( $query, $query2 );
2034                 $server = $wgInternalServer !== false ? $wgInternalServer : $wgServer;
2035                 $url = wfExpandUrl( $server . $this->getLocalURL( $query ), PROTO_HTTP );
2036                 // Avoid PHP 7.1 warning from passing $this by reference
2037                 $titleRef = $this;
2038                 Hooks::run( 'GetInternalURL', [ &$titleRef, &$url, $query ] );
2039                 return $url;
2040         }
2041
2042         /**
2043          * Get the URL for a canonical link, for use in things like IRC and
2044          * e-mail notifications. Uses $wgCanonicalServer and the
2045          * GetCanonicalURL hook.
2046          *
2047          * NOTE: Unlike getInternalURL(), the canonical URL includes the fragment
2048          *
2049          * @see self::getLocalURL for the arguments.
2050          * @param string $query
2051          * @param string|bool $query2
2052          * @return string The URL
2053          * @since 1.18
2054          */
2055         public function getCanonicalURL( $query = '', $query2 = false ) {
2056                 $query = self::fixUrlQueryArgs( $query, $query2 );
2057                 $url = wfExpandUrl( $this->getLocalURL( $query ) . $this->getFragmentForURL(), PROTO_CANONICAL );
2058                 // Avoid PHP 7.1 warning from passing $this by reference
2059                 $titleRef = $this;
2060                 Hooks::run( 'GetCanonicalURL', [ &$titleRef, &$url, $query ] );
2061                 return $url;
2062         }
2063
2064         /**
2065          * Get the edit URL for this Title
2066          *
2067          * @return string The URL, or a null string if this is an interwiki link
2068          */
2069         public function getEditURL() {
2070                 if ( $this->isExternal() ) {
2071                         return '';
2072                 }
2073                 $s = $this->getLocalURL( 'action=edit' );
2074
2075                 return $s;
2076         }
2077
2078         /**
2079          * Can $user perform $action on this page?
2080          * This skips potentially expensive cascading permission checks
2081          * as well as avoids expensive error formatting
2082          *
2083          * Suitable for use for nonessential UI controls in common cases, but
2084          * _not_ for functional access control.
2085          *
2086          * May provide false positives, but should never provide a false negative.
2087          *
2088          * @param string $action Action that permission needs to be checked for
2089          * @param User $user User to check (since 1.19); $wgUser will be used if not provided.
2090          * @return bool
2091          */
2092         public function quickUserCan( $action, $user = null ) {
2093                 return $this->userCan( $action, $user, false );
2094         }
2095
2096         /**
2097          * Can $user perform $action on this page?
2098          *
2099          * @param string $action Action that permission needs to be checked for
2100          * @param User $user User to check (since 1.19); $wgUser will be used if not
2101          *   provided.
2102          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2103          * @return bool
2104          */
2105         public function userCan( $action, $user = null, $rigor = 'secure' ) {
2106                 if ( !$user instanceof User ) {
2107                         global $wgUser;
2108                         $user = $wgUser;
2109                 }
2110
2111                 return !count( $this->getUserPermissionsErrorsInternal( $action, $user, $rigor, true ) );
2112         }
2113
2114         /**
2115          * Can $user perform $action on this page?
2116          *
2117          * @todo FIXME: This *does not* check throttles (User::pingLimiter()).
2118          *
2119          * @param string $action Action that permission needs to be checked for
2120          * @param User $user User to check
2121          * @param string $rigor One of (quick,full,secure)
2122          *   - quick  : does cheap permission checks from replica DBs (usable for GUI creation)
2123          *   - full   : does cheap and expensive checks possibly from a replica DB
2124          *   - secure : does cheap and expensive checks, using the master as needed
2125          * @param array $ignoreErrors Array of Strings Set this to a list of message keys
2126          *   whose corresponding errors may be ignored.
2127          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
2128          */
2129         public function getUserPermissionsErrors(
2130                 $action, $user, $rigor = 'secure', $ignoreErrors = []
2131         ) {
2132                 $errors = $this->getUserPermissionsErrorsInternal( $action, $user, $rigor );
2133
2134                 // Remove the errors being ignored.
2135                 foreach ( $errors as $index => $error ) {
2136                         $errKey = is_array( $error ) ? $error[0] : $error;
2137
2138                         if ( in_array( $errKey, $ignoreErrors ) ) {
2139                                 unset( $errors[$index] );
2140                         }
2141                         if ( $errKey instanceof MessageSpecifier && in_array( $errKey->getKey(), $ignoreErrors ) ) {
2142                                 unset( $errors[$index] );
2143                         }
2144                 }
2145
2146                 return $errors;
2147         }
2148
2149         /**
2150          * Permissions checks that fail most often, and which are easiest to test.
2151          *
2152          * @param string $action The action to check
2153          * @param User $user User to check
2154          * @param array $errors List of current errors
2155          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2156          * @param bool $short Short circuit on first error
2157          *
2158          * @return array List of errors
2159          */
2160         private function checkQuickPermissions( $action, $user, $errors, $rigor, $short ) {
2161                 if ( !Hooks::run( 'TitleQuickPermissions',
2162                         [ $this, $user, $action, &$errors, ( $rigor !== 'quick' ), $short ] )
2163                 ) {
2164                         return $errors;
2165                 }
2166
2167                 if ( $action == 'create' ) {
2168                         if (
2169                                 ( $this->isTalkPage() && !$user->isAllowed( 'createtalk' ) ) ||
2170                                 ( !$this->isTalkPage() && !$user->isAllowed( 'createpage' ) )
2171                         ) {
2172                                 $errors[] = $user->isAnon() ? [ 'nocreatetext' ] : [ 'nocreate-loggedin' ];
2173                         }
2174                 } elseif ( $action == 'move' ) {
2175                         if ( !$user->isAllowed( 'move-rootuserpages' )
2176                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
2177                                 // Show user page-specific message only if the user can move other pages
2178                                 $errors[] = [ 'cant-move-user-page' ];
2179                         }
2180
2181                         // Check if user is allowed to move files if it's a file
2182                         if ( $this->mNamespace == NS_FILE && !$user->isAllowed( 'movefile' ) ) {
2183                                 $errors[] = [ 'movenotallowedfile' ];
2184                         }
2185
2186                         // Check if user is allowed to move category pages if it's a category page
2187                         if ( $this->mNamespace == NS_CATEGORY && !$user->isAllowed( 'move-categorypages' ) ) {
2188                                 $errors[] = [ 'cant-move-category-page' ];
2189                         }
2190
2191                         if ( !$user->isAllowed( 'move' ) ) {
2192                                 // User can't move anything
2193                                 $userCanMove = User::groupHasPermission( 'user', 'move' );
2194                                 $autoconfirmedCanMove = User::groupHasPermission( 'autoconfirmed', 'move' );
2195                                 if ( $user->isAnon() && ( $userCanMove || $autoconfirmedCanMove ) ) {
2196                                         // custom message if logged-in users without any special rights can move
2197                                         $errors[] = [ 'movenologintext' ];
2198                                 } else {
2199                                         $errors[] = [ 'movenotallowed' ];
2200                                 }
2201                         }
2202                 } elseif ( $action == 'move-target' ) {
2203                         if ( !$user->isAllowed( 'move' ) ) {
2204                                 // User can't move anything
2205                                 $errors[] = [ 'movenotallowed' ];
2206                         } elseif ( !$user->isAllowed( 'move-rootuserpages' )
2207                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
2208                                 // Show user page-specific message only if the user can move other pages
2209                                 $errors[] = [ 'cant-move-to-user-page' ];
2210                         } elseif ( !$user->isAllowed( 'move-categorypages' )
2211                                         && $this->mNamespace == NS_CATEGORY ) {
2212                                 // Show category page-specific message only if the user can move other pages
2213                                 $errors[] = [ 'cant-move-to-category-page' ];
2214                         }
2215                 } elseif ( !$user->isAllowed( $action ) ) {
2216                         $errors[] = $this->missingPermissionError( $action, $short );
2217                 }
2218
2219                 return $errors;
2220         }
2221
2222         /**
2223          * Add the resulting error code to the errors array
2224          *
2225          * @param array $errors List of current errors
2226          * @param array $result Result of errors
2227          *
2228          * @return array List of errors
2229          */
2230         private function resultToError( $errors, $result ) {
2231                 if ( is_array( $result ) && count( $result ) && !is_array( $result[0] ) ) {
2232                         // A single array representing an error
2233                         $errors[] = $result;
2234                 } elseif ( is_array( $result ) && is_array( $result[0] ) ) {
2235                         // A nested array representing multiple errors
2236                         $errors = array_merge( $errors, $result );
2237                 } elseif ( $result !== '' && is_string( $result ) ) {
2238                         // A string representing a message-id
2239                         $errors[] = [ $result ];
2240                 } elseif ( $result instanceof MessageSpecifier ) {
2241                         // A message specifier representing an error
2242                         $errors[] = [ $result ];
2243                 } elseif ( $result === false ) {
2244                         // a generic "We don't want them to do that"
2245                         $errors[] = [ 'badaccess-group0' ];
2246                 }
2247                 return $errors;
2248         }
2249
2250         /**
2251          * Check various permission hooks
2252          *
2253          * @param string $action The action to check
2254          * @param User $user User to check
2255          * @param array $errors List of current errors
2256          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2257          * @param bool $short Short circuit on first error
2258          *
2259          * @return array List of errors
2260          */
2261         private function checkPermissionHooks( $action, $user, $errors, $rigor, $short ) {
2262                 // Use getUserPermissionsErrors instead
2263                 $result = '';
2264                 // Avoid PHP 7.1 warning from passing $this by reference
2265                 $titleRef = $this;
2266                 if ( !Hooks::run( 'userCan', [ &$titleRef, &$user, $action, &$result ] ) ) {
2267                         return $result ? [] : [ [ 'badaccess-group0' ] ];
2268                 }
2269                 // Check getUserPermissionsErrors hook
2270                 // Avoid PHP 7.1 warning from passing $this by reference
2271                 $titleRef = $this;
2272                 if ( !Hooks::run( 'getUserPermissionsErrors', [ &$titleRef, &$user, $action, &$result ] ) ) {
2273                         $errors = $this->resultToError( $errors, $result );
2274                 }
2275                 // Check getUserPermissionsErrorsExpensive hook
2276                 if (
2277                         $rigor !== 'quick'
2278                         && !( $short && count( $errors ) > 0 )
2279                         && !Hooks::run( 'getUserPermissionsErrorsExpensive', [ &$titleRef, &$user, $action, &$result ] )
2280                 ) {
2281                         $errors = $this->resultToError( $errors, $result );
2282                 }
2283
2284                 return $errors;
2285         }
2286
2287         /**
2288          * Check permissions on special pages & namespaces
2289          *
2290          * @param string $action The action to check
2291          * @param User $user User to check
2292          * @param array $errors List of current errors
2293          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2294          * @param bool $short Short circuit on first error
2295          *
2296          * @return array List of errors
2297          */
2298         private function checkSpecialsAndNSPermissions( $action, $user, $errors, $rigor, $short ) {
2299                 # Only 'createaccount' can be performed on special pages,
2300                 # which don't actually exist in the DB.
2301                 if ( $this->isSpecialPage() && $action !== 'createaccount' ) {
2302                         $errors[] = [ 'ns-specialprotected' ];
2303                 }
2304
2305                 # Check $wgNamespaceProtection for restricted namespaces
2306                 if ( $this->isNamespaceProtected( $user ) ) {
2307                         $ns = $this->mNamespace == NS_MAIN ?
2308                                 wfMessage( 'nstab-main' )->text() : $this->getNsText();
2309                         $errors[] = $this->mNamespace == NS_MEDIAWIKI ?
2310                                 [ 'protectedinterface', $action ] : [ 'namespaceprotected', $ns, $action ];
2311                 }
2312
2313                 return $errors;
2314         }
2315
2316         /**
2317          * Check CSS/JSON/JS sub-page permissions
2318          *
2319          * @param string $action The action to check
2320          * @param User $user User to check
2321          * @param array $errors List of current errors
2322          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2323          * @param bool $short Short circuit on first error
2324          *
2325          * @return array List of errors
2326          */
2327         private function checkUserConfigPermissions( $action, $user, $errors, $rigor, $short ) {
2328                 # Protect css/json/js subpages of user pages
2329                 # XXX: this might be better using restrictions
2330
2331                 if ( $action != 'patrol' ) {
2332                         if ( preg_match( '/^' . preg_quote( $user->getName(), '/' ) . '\//', $this->mTextform ) ) {
2333                                 if (
2334                                         $this->isUserCssConfigPage()
2335                                         && !$user->isAllowedAny( 'editmyusercss', 'editusercss' )
2336                                 ) {
2337                                         $errors[] = [ 'mycustomcssprotected', $action ];
2338                                 } elseif (
2339                                         $this->isUserJsonConfigPage()
2340                                         && !$user->isAllowedAny( 'editmyuserjson', 'edituserjson' )
2341                                 ) {
2342                                         $errors[] = [ 'mycustomjsonprotected', $action ];
2343                                 } elseif (
2344                                         $this->isUserJsConfigPage()
2345                                         && !$user->isAllowedAny( 'editmyuserjs', 'edituserjs' )
2346                                 ) {
2347                                         $errors[] = [ 'mycustomjsprotected', $action ];
2348                                 }
2349                         } else {
2350                                 if (
2351                                         $this->isUserCssConfigPage()
2352                                         && !$user->isAllowed( 'editusercss' )
2353                                 ) {
2354                                         $errors[] = [ 'customcssprotected', $action ];
2355                                 } elseif (
2356                                         $this->isUserJsonConfigPage()
2357                                         && !$user->isAllowed( 'edituserjson' )
2358                                 ) {
2359                                         $errors[] = [ 'customjsonprotected', $action ];
2360                                 } elseif (
2361                                         $this->isUserJsConfigPage()
2362                                         && !$user->isAllowed( 'edituserjs' )
2363                                 ) {
2364                                         $errors[] = [ 'customjsprotected', $action ];
2365                                 }
2366                         }
2367                 }
2368
2369                 return $errors;
2370         }
2371
2372         /**
2373          * Check against page_restrictions table requirements on this
2374          * page. The user must possess all required rights for this
2375          * action.
2376          *
2377          * @param string $action The action to check
2378          * @param User $user User to check
2379          * @param array $errors List of current errors
2380          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2381          * @param bool $short Short circuit on first error
2382          *
2383          * @return array List of errors
2384          */
2385         private function checkPageRestrictions( $action, $user, $errors, $rigor, $short ) {
2386                 foreach ( $this->getRestrictions( $action ) as $right ) {
2387                         // Backwards compatibility, rewrite sysop -> editprotected
2388                         if ( $right == 'sysop' ) {
2389                                 $right = 'editprotected';
2390                         }
2391                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2392                         if ( $right == 'autoconfirmed' ) {
2393                                 $right = 'editsemiprotected';
2394                         }
2395                         if ( $right == '' ) {
2396                                 continue;
2397                         }
2398                         if ( !$user->isAllowed( $right ) ) {
2399                                 $errors[] = [ 'protectedpagetext', $right, $action ];
2400                         } elseif ( $this->mCascadeRestriction && !$user->isAllowed( 'protect' ) ) {
2401                                 $errors[] = [ 'protectedpagetext', 'protect', $action ];
2402                         }
2403                 }
2404
2405                 return $errors;
2406         }
2407
2408         /**
2409          * Check restrictions on cascading pages.
2410          *
2411          * @param string $action The action to check
2412          * @param User $user User to check
2413          * @param array $errors List of current errors
2414          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2415          * @param bool $short Short circuit on first error
2416          *
2417          * @return array List of errors
2418          */
2419         private function checkCascadingSourcesRestrictions( $action, $user, $errors, $rigor, $short ) {
2420                 if ( $rigor !== 'quick' && !$this->isUserConfigPage() ) {
2421                         # We /could/ use the protection level on the source page, but it's
2422                         # fairly ugly as we have to establish a precedence hierarchy for pages
2423                         # included by multiple cascade-protected pages. So just restrict
2424                         # it to people with 'protect' permission, as they could remove the
2425                         # protection anyway.
2426                         list( $cascadingSources, $restrictions ) = $this->getCascadeProtectionSources();
2427                         # Cascading protection depends on more than this page...
2428                         # Several cascading protected pages may include this page...
2429                         # Check each cascading level
2430                         # This is only for protection restrictions, not for all actions
2431                         if ( isset( $restrictions[$action] ) ) {
2432                                 foreach ( $restrictions[$action] as $right ) {
2433                                         // Backwards compatibility, rewrite sysop -> editprotected
2434                                         if ( $right == 'sysop' ) {
2435                                                 $right = 'editprotected';
2436                                         }
2437                                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2438                                         if ( $right == 'autoconfirmed' ) {
2439                                                 $right = 'editsemiprotected';
2440                                         }
2441                                         if ( $right != '' && !$user->isAllowedAll( 'protect', $right ) ) {
2442                                                 $pages = '';
2443                                                 foreach ( $cascadingSources as $page ) {
2444                                                         $pages .= '* [[:' . $page->getPrefixedText() . "]]\n";
2445                                                 }
2446                                                 $errors[] = [ 'cascadeprotected', count( $cascadingSources ), $pages, $action ];
2447                                         }
2448                                 }
2449                         }
2450                 }
2451
2452                 return $errors;
2453         }
2454
2455         /**
2456          * Check action permissions not already checked in checkQuickPermissions
2457          *
2458          * @param string $action The action to check
2459          * @param User $user User to check
2460          * @param array $errors List of current errors
2461          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2462          * @param bool $short Short circuit on first error
2463          *
2464          * @return array List of errors
2465          */
2466         private function checkActionPermissions( $action, $user, $errors, $rigor, $short ) {
2467                 global $wgDeleteRevisionsLimit, $wgLang;
2468
2469                 if ( $action == 'protect' ) {
2470                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit', $user, $rigor, true ) ) ) {
2471                                 // If they can't edit, they shouldn't protect.
2472                                 $errors[] = [ 'protect-cantedit' ];
2473                         }
2474                 } elseif ( $action == 'create' ) {
2475                         $title_protection = $this->getTitleProtection();
2476                         if ( $title_protection ) {
2477                                 if ( $title_protection['permission'] == ''
2478                                         || !$user->isAllowed( $title_protection['permission'] )
2479                                 ) {
2480                                         $errors[] = [
2481                                                 'titleprotected',
2482                                                 User::whoIs( $title_protection['user'] ),
2483                                                 $title_protection['reason']
2484                                         ];
2485                                 }
2486                         }
2487                 } elseif ( $action == 'move' ) {
2488                         // Check for immobile pages
2489                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2490                                 // Specific message for this case
2491                                 $errors[] = [ 'immobile-source-namespace', $this->getNsText() ];
2492                         } elseif ( !$this->isMovable() ) {
2493                                 // Less specific message for rarer cases
2494                                 $errors[] = [ 'immobile-source-page' ];
2495                         }
2496                 } elseif ( $action == 'move-target' ) {
2497                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2498                                 $errors[] = [ 'immobile-target-namespace', $this->getNsText() ];
2499                         } elseif ( !$this->isMovable() ) {
2500                                 $errors[] = [ 'immobile-target-page' ];
2501                         }
2502                 } elseif ( $action == 'delete' ) {
2503                         $tempErrors = $this->checkPageRestrictions( 'edit', $user, [], $rigor, true );
2504                         if ( !$tempErrors ) {
2505                                 $tempErrors = $this->checkCascadingSourcesRestrictions( 'edit',
2506                                         $user, $tempErrors, $rigor, true );
2507                         }
2508                         if ( $tempErrors ) {
2509                                 // If protection keeps them from editing, they shouldn't be able to delete.
2510                                 $errors[] = [ 'deleteprotected' ];
2511                         }
2512                         if ( $rigor !== 'quick' && $wgDeleteRevisionsLimit
2513                                 && !$this->userCan( 'bigdelete', $user ) && $this->isBigDeletion()
2514                         ) {
2515                                 $errors[] = [ 'delete-toobig', $wgLang->formatNum( $wgDeleteRevisionsLimit ) ];
2516                         }
2517                 } elseif ( $action === 'undelete' ) {
2518                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit', $user, $rigor, true ) ) ) {
2519                                 // Undeleting implies editing
2520                                 $errors[] = [ 'undelete-cantedit' ];
2521                         }
2522                         if ( !$this->exists()
2523                                 && count( $this->getUserPermissionsErrorsInternal( 'create', $user, $rigor, true ) )
2524                         ) {
2525                                 // Undeleting where nothing currently exists implies creating
2526                                 $errors[] = [ 'undelete-cantcreate' ];
2527                         }
2528                 }
2529                 return $errors;
2530         }
2531
2532         /**
2533          * Check that the user isn't blocked from editing.
2534          *
2535          * @param string $action The action to check
2536          * @param User $user User to check
2537          * @param array $errors List of current errors
2538          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2539          * @param bool $short Short circuit on first error
2540          *
2541          * @return array List of errors
2542          */
2543         private function checkUserBlock( $action, $user, $errors, $rigor, $short ) {
2544                 global $wgEmailConfirmToEdit, $wgBlockDisablesLogin;
2545                 // Account creation blocks handled at userlogin.
2546                 // Unblocking handled in SpecialUnblock
2547                 if ( $rigor === 'quick' || in_array( $action, [ 'createaccount', 'unblock' ] ) ) {
2548                         return $errors;
2549                 }
2550
2551                 // Optimize for a very common case
2552                 if ( $action === 'read' && !$wgBlockDisablesLogin ) {
2553                         return $errors;
2554                 }
2555
2556                 if ( $wgEmailConfirmToEdit
2557                         && !$user->isEmailConfirmed()
2558                         && $action === 'edit'
2559                 ) {
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 $this->mRestrictions[$action] ?? [];
3093         }
3094
3095         /**
3096          * Accessor/initialisation for mRestrictions
3097          *
3098          * @return array Keys are actions, values are arrays as returned by
3099          *     Title::getRestrictions()
3100          * @since 1.23
3101          */
3102         public function getAllRestrictions() {
3103                 if ( !$this->mRestrictionsLoaded ) {
3104                         $this->loadRestrictions();
3105                 }
3106                 return $this->mRestrictions;
3107         }
3108
3109         /**
3110          * Get the expiry time for the restriction against a given action
3111          *
3112          * @param string $action
3113          * @return string|bool 14-char timestamp, or 'infinity' if the page is protected forever
3114          *     or not protected at all, or false if the action is not recognised.
3115          */
3116         public function getRestrictionExpiry( $action ) {
3117                 if ( !$this->mRestrictionsLoaded ) {
3118                         $this->loadRestrictions();
3119                 }
3120                 return $this->mRestrictionsExpiry[$action] ?? false;
3121         }
3122
3123         /**
3124          * Returns cascading restrictions for the current article
3125          *
3126          * @return bool
3127          */
3128         function areRestrictionsCascading() {
3129                 if ( !$this->mRestrictionsLoaded ) {
3130                         $this->loadRestrictions();
3131                 }
3132
3133                 return $this->mCascadeRestriction;
3134         }
3135
3136         /**
3137          * Compiles list of active page restrictions from both page table (pre 1.10)
3138          * and page_restrictions table for this existing page.
3139          * Public for usage by LiquidThreads.
3140          *
3141          * @param array $rows Array of db result objects
3142          * @param string $oldFashionedRestrictions Comma-separated set of permission keys
3143          * indicating who can move or edit the page from the page table, (pre 1.10) rows.
3144          * Edit and move sections are separated by a colon
3145          * Example: "edit=autoconfirmed,sysop:move=sysop"
3146          */
3147         public function loadRestrictionsFromRows( $rows, $oldFashionedRestrictions = null ) {
3148                 $dbr = wfGetDB( DB_REPLICA );
3149
3150                 $restrictionTypes = $this->getRestrictionTypes();
3151
3152                 foreach ( $restrictionTypes as $type ) {
3153                         $this->mRestrictions[$type] = [];
3154                         $this->mRestrictionsExpiry[$type] = 'infinity';
3155                 }
3156
3157                 $this->mCascadeRestriction = false;
3158
3159                 # Backwards-compatibility: also load the restrictions from the page record (old format).
3160                 if ( $oldFashionedRestrictions !== null ) {
3161                         $this->mOldRestrictions = $oldFashionedRestrictions;
3162                 }
3163
3164                 if ( $this->mOldRestrictions === false ) {
3165                         $this->mOldRestrictions = $dbr->selectField( 'page', 'page_restrictions',
3166                                 [ 'page_id' => $this->getArticleID() ], __METHOD__ );
3167                 }
3168
3169                 if ( $this->mOldRestrictions != '' ) {
3170                         foreach ( explode( ':', trim( $this->mOldRestrictions ) ) as $restrict ) {
3171                                 $temp = explode( '=', trim( $restrict ) );
3172                                 if ( count( $temp ) == 1 ) {
3173                                         // old old format should be treated as edit/move restriction
3174                                         $this->mRestrictions['edit'] = explode( ',', trim( $temp[0] ) );
3175                                         $this->mRestrictions['move'] = explode( ',', trim( $temp[0] ) );
3176                                 } else {
3177                                         $restriction = trim( $temp[1] );
3178                                         if ( $restriction != '' ) { // some old entries are empty
3179                                                 $this->mRestrictions[$temp[0]] = explode( ',', $restriction );
3180                                         }
3181                                 }
3182                         }
3183                 }
3184
3185                 if ( count( $rows ) ) {
3186                         # Current system - load second to make them override.
3187                         $now = wfTimestampNow();
3188
3189                         # Cycle through all the restrictions.
3190                         foreach ( $rows as $row ) {
3191                                 // Don't take care of restrictions types that aren't allowed
3192                                 if ( !in_array( $row->pr_type, $restrictionTypes ) ) {
3193                                         continue;
3194                                 }
3195
3196                                 $expiry = $dbr->decodeExpiry( $row->pr_expiry );
3197
3198                                 // Only apply the restrictions if they haven't expired!
3199                                 if ( !$expiry || $expiry > $now ) {
3200                                         $this->mRestrictionsExpiry[$row->pr_type] = $expiry;
3201                                         $this->mRestrictions[$row->pr_type] = explode( ',', trim( $row->pr_level ) );
3202
3203                                         $this->mCascadeRestriction |= $row->pr_cascade;
3204                                 }
3205                         }
3206                 }
3207
3208                 $this->mRestrictionsLoaded = true;
3209         }
3210
3211         /**
3212          * Load restrictions from the page_restrictions table
3213          *
3214          * @param string $oldFashionedRestrictions Comma-separated set of permission keys
3215          * indicating who can move or edit the page from the page table, (pre 1.10) rows.
3216          * Edit and move sections are separated by a colon
3217          * Example: "edit=autoconfirmed,sysop:move=sysop"
3218          */
3219         public function loadRestrictions( $oldFashionedRestrictions = null ) {
3220                 if ( $this->mRestrictionsLoaded ) {
3221                         return;
3222                 }
3223
3224                 $id = $this->getArticleID();
3225                 if ( $id ) {
3226                         $cache = ObjectCache::getMainWANInstance();
3227                         $rows = $cache->getWithSetCallback(
3228                                 // Page protections always leave a new null revision
3229                                 $cache->makeKey( 'page-restrictions', $id, $this->getLatestRevID() ),
3230                                 $cache::TTL_DAY,
3231                                 function ( $curValue, &$ttl, array &$setOpts ) {
3232                                         $dbr = wfGetDB( DB_REPLICA );
3233
3234                                         $setOpts += Database::getCacheSetOptions( $dbr );
3235
3236                                         return iterator_to_array(
3237                                                 $dbr->select(
3238                                                         'page_restrictions',
3239                                                         [ 'pr_type', 'pr_expiry', 'pr_level', 'pr_cascade' ],
3240                                                         [ 'pr_page' => $this->getArticleID() ],
3241                                                         __METHOD__
3242                                                 )
3243                                         );
3244                                 }
3245                         );
3246
3247                         $this->loadRestrictionsFromRows( $rows, $oldFashionedRestrictions );
3248                 } else {
3249                         $title_protection = $this->getTitleProtectionInternal();
3250
3251                         if ( $title_protection ) {
3252                                 $now = wfTimestampNow();
3253                                 $expiry = wfGetDB( DB_REPLICA )->decodeExpiry( $title_protection['expiry'] );
3254
3255                                 if ( !$expiry || $expiry > $now ) {
3256                                         // Apply the restrictions
3257                                         $this->mRestrictionsExpiry['create'] = $expiry;
3258                                         $this->mRestrictions['create'] =
3259                                                 explode( ',', trim( $title_protection['permission'] ) );
3260                                 } else { // Get rid of the old restrictions
3261                                         $this->mTitleProtection = false;
3262                                 }
3263                         } else {
3264                                 $this->mRestrictionsExpiry['create'] = 'infinity';
3265                         }
3266                         $this->mRestrictionsLoaded = true;
3267                 }
3268         }
3269
3270         /**
3271          * Flush the protection cache in this object and force reload from the database.
3272          * This is used when updating protection from WikiPage::doUpdateRestrictions().
3273          */
3274         public function flushRestrictions() {
3275                 $this->mRestrictionsLoaded = false;
3276                 $this->mTitleProtection = null;
3277         }
3278
3279         /**
3280          * Purge expired restrictions from the page_restrictions table
3281          *
3282          * This will purge no more than $wgUpdateRowsPerQuery page_restrictions rows
3283          */
3284         static function purgeExpiredRestrictions() {
3285                 if ( wfReadOnly() ) {
3286                         return;
3287                 }
3288
3289                 DeferredUpdates::addUpdate( new AtomicSectionUpdate(
3290                         wfGetDB( DB_MASTER ),
3291                         __METHOD__,
3292                         function ( IDatabase $dbw, $fname ) {
3293                                 $config = MediaWikiServices::getInstance()->getMainConfig();
3294                                 $ids = $dbw->selectFieldValues(
3295                                         'page_restrictions',
3296                                         'pr_id',
3297                                         [ 'pr_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ],
3298                                         $fname,
3299                                         [ 'LIMIT' => $config->get( 'UpdateRowsPerQuery' ) ] // T135470
3300                                 );
3301                                 if ( $ids ) {
3302                                         $dbw->delete( 'page_restrictions', [ 'pr_id' => $ids ], $fname );
3303                                 }
3304                         }
3305                 ) );
3306
3307                 DeferredUpdates::addUpdate( new AtomicSectionUpdate(
3308                         wfGetDB( DB_MASTER ),
3309                         __METHOD__,
3310                         function ( IDatabase $dbw, $fname ) {
3311                                 $dbw->delete(
3312                                         'protected_titles',
3313                                         [ 'pt_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ],
3314                                         $fname
3315                                 );
3316                         }
3317                 ) );
3318         }
3319
3320         /**
3321          * Does this have subpages?  (Warning, usually requires an extra DB query.)
3322          *
3323          * @return bool
3324          */
3325         public function hasSubpages() {
3326                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
3327                         # Duh
3328                         return false;
3329                 }
3330
3331                 # We dynamically add a member variable for the purpose of this method
3332                 # alone to cache the result.  There's no point in having it hanging
3333                 # around uninitialized in every Title object; therefore we only add it
3334                 # if needed and don't declare it statically.
3335                 if ( $this->mHasSubpages === null ) {
3336                         $this->mHasSubpages = false;
3337                         $subpages = $this->getSubpages( 1 );
3338                         if ( $subpages instanceof TitleArray ) {
3339                                 $this->mHasSubpages = (bool)$subpages->count();
3340                         }
3341                 }
3342
3343                 return $this->mHasSubpages;
3344         }
3345
3346         /**
3347          * Get all subpages of this page.
3348          *
3349          * @param int $limit Maximum number of subpages to fetch; -1 for no limit
3350          * @return TitleArray|array TitleArray, or empty array if this page's namespace
3351          *  doesn't allow subpages
3352          */
3353         public function getSubpages( $limit = -1 ) {
3354                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3355                         return [];
3356                 }
3357
3358                 $dbr = wfGetDB( DB_REPLICA );
3359                 $conds['page_namespace'] = $this->getNamespace();
3360                 $conds[] = 'page_title ' . $dbr->buildLike( $this->getDBkey() . '/', $dbr->anyString() );
3361                 $options = [];
3362                 if ( $limit > -1 ) {
3363                         $options['LIMIT'] = $limit;
3364                 }
3365                 return TitleArray::newFromResult(
3366                         $dbr->select( 'page',
3367                                 [ 'page_id', 'page_namespace', 'page_title', 'page_is_redirect' ],
3368                                 $conds,
3369                                 __METHOD__,
3370                                 $options
3371                         )
3372                 );
3373         }
3374
3375         /**
3376          * Is there a version of this page in the deletion archive?
3377          *
3378          * @return int The number of archived revisions
3379          */
3380         public function isDeleted() {
3381                 if ( $this->getNamespace() < 0 ) {
3382                         $n = 0;
3383                 } else {
3384                         $dbr = wfGetDB( DB_REPLICA );
3385
3386                         $n = $dbr->selectField( 'archive', 'COUNT(*)',
3387                                 [ 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ],
3388                                 __METHOD__
3389                         );
3390                         if ( $this->getNamespace() == NS_FILE ) {
3391                                 $n += $dbr->selectField( 'filearchive', 'COUNT(*)',
3392                                         [ 'fa_name' => $this->getDBkey() ],
3393                                         __METHOD__
3394                                 );
3395                         }
3396                 }
3397                 return (int)$n;
3398         }
3399
3400         /**
3401          * Is there a version of this page in the deletion archive?
3402          *
3403          * @return bool
3404          */
3405         public function isDeletedQuick() {
3406                 if ( $this->getNamespace() < 0 ) {
3407                         return false;
3408                 }
3409                 $dbr = wfGetDB( DB_REPLICA );
3410                 $deleted = (bool)$dbr->selectField( 'archive', '1',
3411                         [ 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ],
3412                         __METHOD__
3413                 );
3414                 if ( !$deleted && $this->getNamespace() == NS_FILE ) {
3415                         $deleted = (bool)$dbr->selectField( 'filearchive', '1',
3416                                 [ 'fa_name' => $this->getDBkey() ],
3417                                 __METHOD__
3418                         );
3419                 }
3420                 return $deleted;
3421         }
3422
3423         /**
3424          * Get the article ID for this Title from the link cache,
3425          * adding it if necessary
3426          *
3427          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select
3428          *  for update
3429          * @return int The ID
3430          */
3431         public function getArticleID( $flags = 0 ) {
3432                 if ( $this->getNamespace() < 0 ) {
3433                         $this->mArticleID = 0;
3434                         return $this->mArticleID;
3435                 }
3436                 $linkCache = MediaWikiServices::getInstance()->getLinkCache();
3437                 if ( $flags & self::GAID_FOR_UPDATE ) {
3438                         $oldUpdate = $linkCache->forUpdate( true );
3439                         $linkCache->clearLink( $this );
3440                         $this->mArticleID = $linkCache->addLinkObj( $this );
3441                         $linkCache->forUpdate( $oldUpdate );
3442                 } else {
3443                         if ( -1 == $this->mArticleID ) {
3444                                 $this->mArticleID = $linkCache->addLinkObj( $this );
3445                         }
3446                 }
3447                 return $this->mArticleID;
3448         }
3449
3450         /**
3451          * Is this an article that is a redirect page?
3452          * Uses link cache, adding it if necessary
3453          *
3454          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3455          * @return bool
3456          */
3457         public function isRedirect( $flags = 0 ) {
3458                 if ( !is_null( $this->mRedirect ) ) {
3459                         return $this->mRedirect;
3460                 }
3461                 if ( !$this->getArticleID( $flags ) ) {
3462                         $this->mRedirect = false;
3463                         return $this->mRedirect;
3464                 }
3465
3466                 $linkCache = MediaWikiServices::getInstance()->getLinkCache();
3467                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3468                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'redirect' );
3469                 if ( $cached === null ) {
3470                         # Trust LinkCache's state over our own
3471                         # LinkCache is telling us that the page doesn't exist, despite there being cached
3472                         # data relating to an existing page in $this->mArticleID. Updaters should clear
3473                         # LinkCache as appropriate, or use $flags = Title::GAID_FOR_UPDATE. If that flag is
3474                         # set, then LinkCache will definitely be up to date here, since getArticleID() forces
3475                         # LinkCache to refresh its data from the master.
3476                         $this->mRedirect = false;
3477                         return $this->mRedirect;
3478                 }
3479
3480                 $this->mRedirect = (bool)$cached;
3481
3482                 return $this->mRedirect;
3483         }
3484
3485         /**
3486          * What is the length of this page?
3487          * Uses link cache, adding it if necessary
3488          *
3489          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3490          * @return int
3491          */
3492         public function getLength( $flags = 0 ) {
3493                 if ( $this->mLength != -1 ) {
3494                         return $this->mLength;
3495                 }
3496                 if ( !$this->getArticleID( $flags ) ) {
3497                         $this->mLength = 0;
3498                         return $this->mLength;
3499                 }
3500                 $linkCache = MediaWikiServices::getInstance()->getLinkCache();
3501                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3502                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'length' );
3503                 if ( $cached === null ) {
3504                         # Trust LinkCache's state over our own, as for isRedirect()
3505                         $this->mLength = 0;
3506                         return $this->mLength;
3507                 }
3508
3509                 $this->mLength = intval( $cached );
3510
3511                 return $this->mLength;
3512         }
3513
3514         /**
3515          * What is the page_latest field for this page?
3516          *
3517          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3518          * @return int Int or 0 if the page doesn't exist
3519          */
3520         public function getLatestRevID( $flags = 0 ) {
3521                 if ( !( $flags & self::GAID_FOR_UPDATE ) && $this->mLatestID !== false ) {
3522                         return intval( $this->mLatestID );
3523                 }
3524                 if ( !$this->getArticleID( $flags ) ) {
3525                         $this->mLatestID = 0;
3526                         return $this->mLatestID;
3527                 }
3528                 $linkCache = MediaWikiServices::getInstance()->getLinkCache();
3529                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3530                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'revision' );
3531                 if ( $cached === null ) {
3532                         # Trust LinkCache's state over our own, as for isRedirect()
3533                         $this->mLatestID = 0;
3534                         return $this->mLatestID;
3535                 }
3536
3537                 $this->mLatestID = intval( $cached );
3538
3539                 return $this->mLatestID;
3540         }
3541
3542         /**
3543          * This clears some fields in this object, and clears any associated
3544          * keys in the "bad links" section of the link cache.
3545          *
3546          * - This is called from WikiPage::doEditContent() and WikiPage::insertOn() to allow
3547          * loading of the new page_id. It's also called from
3548          * WikiPage::doDeleteArticleReal()
3549          *
3550          * @param int $newid The new Article ID
3551          */
3552         public function resetArticleID( $newid ) {
3553                 $linkCache = MediaWikiServices::getInstance()->getLinkCache();
3554                 $linkCache->clearLink( $this );
3555
3556                 if ( $newid === false ) {
3557                         $this->mArticleID = -1;
3558                 } else {
3559                         $this->mArticleID = intval( $newid );
3560                 }
3561                 $this->mRestrictionsLoaded = false;
3562                 $this->mRestrictions = [];
3563                 $this->mOldRestrictions = false;
3564                 $this->mRedirect = null;
3565                 $this->mLength = -1;
3566                 $this->mLatestID = false;
3567                 $this->mContentModel = false;
3568                 $this->mEstimateRevisions = null;
3569                 $this->mPageLanguage = false;
3570                 $this->mDbPageLanguage = false;
3571                 $this->mIsBigDeletion = null;
3572         }
3573
3574         public static function clearCaches() {
3575                 $linkCache = MediaWikiServices::getInstance()->getLinkCache();
3576                 $linkCache->clear();
3577
3578                 $titleCache = self::getTitleCache();
3579                 $titleCache->clear();
3580         }
3581
3582         /**
3583          * Capitalize a text string for a title if it belongs to a namespace that capitalizes
3584          *
3585          * @param string $text Containing title to capitalize
3586          * @param int $ns Namespace index, defaults to NS_MAIN
3587          * @return string Containing capitalized title
3588          */
3589         public static function capitalize( $text, $ns = NS_MAIN ) {
3590                 global $wgContLang;
3591
3592                 if ( MWNamespace::isCapitalized( $ns ) ) {
3593                         return $wgContLang->ucfirst( $text );
3594                 } else {
3595                         return $text;
3596                 }
3597         }
3598
3599         /**
3600          * Secure and split - main initialisation function for this object
3601          *
3602          * Assumes that mDbkeyform has been set, and is urldecoded
3603          * and uses underscores, but not otherwise munged.  This function
3604          * removes illegal characters, splits off the interwiki and
3605          * namespace prefixes, sets the other forms, and canonicalizes
3606          * everything.
3607          *
3608          * @throws MalformedTitleException On invalid titles
3609          * @return bool True on success
3610          */
3611         private function secureAndSplit() {
3612                 # Initialisation
3613                 $this->mInterwiki = '';
3614                 $this->mFragment = '';
3615                 $this->mNamespace = $this->mDefaultNamespace; # Usually NS_MAIN
3616
3617                 $dbkey = $this->mDbkeyform;
3618
3619                 // @note: splitTitleString() is a temporary hack to allow MediaWikiTitleCodec to share
3620                 //        the parsing code with Title, while avoiding massive refactoring.
3621                 // @todo: get rid of secureAndSplit, refactor parsing code.
3622                 // @note: getTitleParser() returns a TitleParser implementation which does not have a
3623                 //        splitTitleString method, but the only implementation (MediaWikiTitleCodec) does
3624                 $titleCodec = MediaWikiServices::getInstance()->getTitleParser();
3625                 // MalformedTitleException can be thrown here
3626                 $parts = $titleCodec->splitTitleString( $dbkey, $this->getDefaultNamespace() );
3627
3628                 # Fill fields
3629                 $this->setFragment( '#' . $parts['fragment'] );
3630                 $this->mInterwiki = $parts['interwiki'];
3631                 $this->mLocalInterwiki = $parts['local_interwiki'];
3632                 $this->mNamespace = $parts['namespace'];
3633                 $this->mUserCaseDBKey = $parts['user_case_dbkey'];
3634
3635                 $this->mDbkeyform = $parts['dbkey'];
3636                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
3637                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
3638
3639                 # We already know that some pages won't be in the database!
3640                 if ( $this->isExternal() || $this->isSpecialPage() ) {
3641                         $this->mArticleID = 0;
3642                 }
3643
3644                 return true;
3645         }
3646
3647         /**
3648          * Get an array of Title objects linking to this Title
3649          * Also stores the IDs in the link cache.
3650          *
3651          * WARNING: do not use this function on arbitrary user-supplied titles!
3652          * On heavily-used templates it will max out the memory.
3653          *
3654          * @param array $options May be FOR UPDATE
3655          * @param string $table Table name
3656          * @param string $prefix Fields prefix
3657          * @return Title[] Array of Title objects linking here
3658          */
3659         public function getLinksTo( $options = [], $table = 'pagelinks', $prefix = 'pl' ) {
3660                 if ( count( $options ) > 0 ) {
3661                         $db = wfGetDB( DB_MASTER );
3662                 } else {
3663                         $db = wfGetDB( DB_REPLICA );
3664                 }
3665
3666                 $res = $db->select(
3667                         [ 'page', $table ],
3668                         self::getSelectFields(),
3669                         [
3670                                 "{$prefix}_from=page_id",
3671                                 "{$prefix}_namespace" => $this->getNamespace(),
3672                                 "{$prefix}_title" => $this->getDBkey() ],
3673                         __METHOD__,
3674                         $options
3675                 );
3676
3677                 $retVal = [];
3678                 if ( $res->numRows() ) {
3679                         $linkCache = MediaWikiServices::getInstance()->getLinkCache();
3680                         foreach ( $res as $row ) {
3681                                 $titleObj = self::makeTitle( $row->page_namespace, $row->page_title );
3682                                 if ( $titleObj ) {
3683                                         $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3684                                         $retVal[] = $titleObj;
3685                                 }
3686                         }
3687                 }
3688                 return $retVal;
3689         }
3690
3691         /**
3692          * Get an array of Title objects using this Title as a template
3693          * Also stores the IDs in the link cache.
3694          *
3695          * WARNING: do not use this function on arbitrary user-supplied titles!
3696          * On heavily-used templates it will max out the memory.
3697          *
3698          * @param array $options Query option to Database::select()
3699          * @return Title[] Array of Title the Title objects linking here
3700          */
3701         public function getTemplateLinksTo( $options = [] ) {
3702                 return $this->getLinksTo( $options, 'templatelinks', 'tl' );
3703         }
3704
3705         /**
3706          * Get an array of Title objects linked from this Title
3707          * Also stores the IDs in the link cache.
3708          *
3709          * WARNING: do not use this function on arbitrary user-supplied titles!
3710          * On heavily-used templates it will max out the memory.
3711          *
3712          * @param array $options Query option to Database::select()
3713          * @param string $table Table name
3714          * @param string $prefix Fields prefix
3715          * @return array Array of Title objects linking here
3716          */
3717         public function getLinksFrom( $options = [], $table = 'pagelinks', $prefix = 'pl' ) {
3718                 $id = $this->getArticleID();
3719
3720                 # If the page doesn't exist; there can't be any link from this page
3721                 if ( !$id ) {
3722                         return [];
3723                 }
3724
3725                 $db = wfGetDB( DB_REPLICA );
3726
3727                 $blNamespace = "{$prefix}_namespace";
3728                 $blTitle = "{$prefix}_title";
3729
3730                 $pageQuery = WikiPage::getQueryInfo();
3731                 $res = $db->select(
3732                         [ $table, 'nestpage' => $pageQuery['tables'] ],
3733                         array_merge(
3734                                 [ $blNamespace, $blTitle ],
3735                                 $pageQuery['fields']
3736                         ),
3737                         [ "{$prefix}_from" => $id ],
3738                         __METHOD__,
3739                         $options,
3740                         [ 'nestpage' => [
3741                                 'LEFT JOIN',
3742                                 [ "page_namespace=$blNamespace", "page_title=$blTitle" ]
3743                         ] ] + $pageQuery['joins']
3744                 );
3745
3746                 $retVal = [];
3747                 $linkCache = MediaWikiServices::getInstance()->getLinkCache();
3748                 foreach ( $res as $row ) {
3749                         if ( $row->page_id ) {
3750                                 $titleObj = self::newFromRow( $row );
3751                         } else {
3752                                 $titleObj = self::makeTitle( $row->$blNamespace, $row->$blTitle );
3753                                 $linkCache->addBadLinkObj( $titleObj );
3754                         }
3755                         $retVal[] = $titleObj;
3756                 }
3757
3758                 return $retVal;
3759         }
3760
3761         /**
3762          * Get an array of Title objects used on this Title as a template
3763          * Also stores the IDs in the link cache.
3764          *
3765          * WARNING: do not use this function on arbitrary user-supplied titles!
3766          * On heavily-used templates it will max out the memory.
3767          *
3768          * @param array $options May be FOR UPDATE
3769          * @return Title[] Array of Title the Title objects used here
3770          */
3771         public function getTemplateLinksFrom( $options = [] ) {
3772                 return $this->getLinksFrom( $options, 'templatelinks', 'tl' );
3773         }
3774
3775         /**
3776          * Get an array of Title objects referring to non-existent articles linked
3777          * from this page.
3778          *
3779          * @todo check if needed (used only in SpecialBrokenRedirects.php, and
3780          *   should use redirect table in this case).
3781          * @return Title[] Array of Title the Title objects
3782          */
3783         public function getBrokenLinksFrom() {
3784                 if ( $this->getArticleID() == 0 ) {
3785                         # All links from article ID 0 are false positives
3786                         return [];
3787                 }
3788
3789                 $dbr = wfGetDB( DB_REPLICA );
3790                 $res = $dbr->select(
3791                         [ 'page', 'pagelinks' ],
3792                         [ 'pl_namespace', 'pl_title' ],
3793                         [
3794                                 'pl_from' => $this->getArticleID(),
3795                                 'page_namespace IS NULL'
3796                         ],
3797                         __METHOD__, [],
3798                         [
3799                                 'page' => [
3800                                         'LEFT JOIN',
3801                                         [ 'pl_namespace=page_namespace', 'pl_title=page_title' ]
3802                                 ]
3803                         ]
3804                 );
3805
3806                 $retVal = [];
3807                 foreach ( $res as $row ) {
3808                         $retVal[] = self::makeTitle( $row->pl_namespace, $row->pl_title );
3809                 }
3810                 return $retVal;
3811         }
3812
3813         /**
3814          * Get a list of URLs to purge from the CDN cache when this
3815          * page changes
3816          *
3817          * @return string[] Array of String the URLs
3818          */
3819         public function getCdnUrls() {
3820                 $urls = [
3821                         $this->getInternalURL(),
3822                         $this->getInternalURL( 'action=history' )
3823                 ];
3824
3825                 $pageLang = $this->getPageLanguage();
3826                 if ( $pageLang->hasVariants() ) {
3827                         $variants = $pageLang->getVariants();
3828                         foreach ( $variants as $vCode ) {
3829                                 $urls[] = $this->getInternalURL( $vCode );
3830                         }
3831                 }
3832
3833                 // If we are looking at a css/js user subpage, purge the action=raw.
3834                 if ( $this->isUserJsConfigPage() ) {
3835                         $urls[] = $this->getInternalURL( 'action=raw&ctype=text/javascript' );
3836                 } elseif ( $this->isUserJsonConfigPage() ) {
3837                         $urls[] = $this->getInternalURL( 'action=raw&ctype=application/json' );
3838                 } elseif ( $this->isUserCssConfigPage() ) {
3839                         $urls[] = $this->getInternalURL( 'action=raw&ctype=text/css' );
3840                 }
3841
3842                 Hooks::run( 'TitleSquidURLs', [ $this, &$urls ] );
3843                 return $urls;
3844         }
3845
3846         /**
3847          * @deprecated since 1.27 use getCdnUrls()
3848          */
3849         public function getSquidURLs() {
3850                 return $this->getCdnUrls();
3851         }
3852
3853         /**
3854          * Purge all applicable CDN URLs
3855          */
3856         public function purgeSquid() {
3857                 DeferredUpdates::addUpdate(
3858                         new CdnCacheUpdate( $this->getCdnUrls() ),
3859                         DeferredUpdates::PRESEND
3860                 );
3861         }
3862
3863         /**
3864          * Check whether a given move operation would be valid.
3865          * Returns true if ok, or a getUserPermissionsErrors()-like array otherwise
3866          *
3867          * @deprecated since 1.25, use MovePage's methods instead
3868          * @param Title &$nt The new title
3869          * @param bool $auth Whether to check user permissions (uses $wgUser)
3870          * @param string $reason Is the log summary of the move, used for spam checking
3871          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3872          */
3873         public function isValidMoveOperation( &$nt, $auth = true, $reason = '' ) {
3874                 global $wgUser;
3875
3876                 if ( !( $nt instanceof Title ) ) {
3877                         // Normally we'd add this to $errors, but we'll get
3878                         // lots of syntax errors if $nt is not an object
3879                         return [ [ 'badtitletext' ] ];
3880                 }
3881
3882                 $mp = new MovePage( $this, $nt );
3883                 $errors = $mp->isValidMove()->getErrorsArray();
3884                 if ( $auth ) {
3885                         $errors = wfMergeErrorArrays(
3886                                 $errors,
3887                                 $mp->checkPermissions( $wgUser, $reason )->getErrorsArray()
3888                         );
3889                 }
3890
3891                 return $errors ?: true;
3892         }
3893
3894         /**
3895          * Check if the requested move target is a valid file move target
3896          * @todo move this to MovePage
3897          * @param Title $nt Target title
3898          * @return array List of errors
3899          */
3900         protected function validateFileMoveOperation( $nt ) {
3901                 global $wgUser;
3902
3903                 $errors = [];
3904
3905                 $destFile = wfLocalFile( $nt );
3906                 $destFile->load( File::READ_LATEST );
3907                 if ( !$wgUser->isAllowed( 'reupload-shared' )
3908                         && !$destFile->exists() && wfFindFile( $nt )
3909                 ) {
3910                         $errors[] = [ 'file-exists-sharedrepo' ];
3911                 }
3912
3913                 return $errors;
3914         }
3915
3916         /**
3917          * Move a title to a new location
3918          *
3919          * @deprecated since 1.25, use the MovePage class instead
3920          * @param Title &$nt The new title
3921          * @param bool $auth Indicates whether $wgUser's permissions
3922          *  should be checked
3923          * @param string $reason The reason for the move
3924          * @param bool $createRedirect Whether to create a redirect from the old title to the new title.
3925          *  Ignored if the user doesn't have the suppressredirect right.
3926          * @param array $changeTags Applied to the entry in the move log and redirect page revision
3927          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3928          */
3929         public function moveTo( &$nt, $auth = true, $reason = '', $createRedirect = true,
3930                 array $changeTags = []
3931         ) {
3932                 global $wgUser;
3933                 $err = $this->isValidMoveOperation( $nt, $auth, $reason );
3934                 if ( is_array( $err ) ) {
3935                         // Auto-block user's IP if the account was "hard" blocked
3936                         $wgUser->spreadAnyEditBlock();
3937                         return $err;
3938                 }
3939                 // Check suppressredirect permission
3940                 if ( $auth && !$wgUser->isAllowed( 'suppressredirect' ) ) {
3941                         $createRedirect = true;
3942                 }
3943
3944                 $mp = new MovePage( $this, $nt );
3945                 $status = $mp->move( $wgUser, $reason, $createRedirect, $changeTags );
3946                 if ( $status->isOK() ) {
3947                         return true;
3948                 } else {
3949                         return $status->getErrorsArray();
3950                 }
3951         }
3952
3953         /**
3954          * Move this page's subpages to be subpages of $nt
3955          *
3956          * @param Title $nt Move target
3957          * @param bool $auth Whether $wgUser's permissions should be checked
3958          * @param string $reason The reason for the move
3959          * @param bool $createRedirect Whether to create redirects from the old subpages to
3960          *     the new ones Ignored if the user doesn't have the 'suppressredirect' right
3961          * @param array $changeTags Applied to the entry in the move log and redirect page revision
3962          * @return array Array with old page titles as keys, and strings (new page titles) or
3963          *     getUserPermissionsErrors()-like arrays (errors) as values, or a
3964          *     getUserPermissionsErrors()-like error array with numeric indices if
3965          *     no pages were moved
3966          */
3967         public function moveSubpages( $nt, $auth = true, $reason = '', $createRedirect = true,
3968                 array $changeTags = []
3969         ) {
3970                 global $wgMaximumMovedPages;
3971                 // Check permissions
3972                 if ( !$this->userCan( 'move-subpages' ) ) {
3973                         return [
3974                                 [ 'cant-move-subpages' ],
3975                         ];
3976                 }
3977                 // Do the source and target namespaces support subpages?
3978                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3979                         return [
3980                                 [ 'namespace-nosubpages', MWNamespace::getCanonicalName( $this->getNamespace() ) ],
3981                         ];
3982                 }
3983                 if ( !MWNamespace::hasSubpages( $nt->getNamespace() ) ) {
3984                         return [
3985                                 [ 'namespace-nosubpages', MWNamespace::getCanonicalName( $nt->getNamespace() ) ],
3986                         ];
3987                 }
3988
3989                 $subpages = $this->getSubpages( $wgMaximumMovedPages + 1 );
3990                 $retval = [];
3991                 $count = 0;
3992                 foreach ( $subpages as $oldSubpage ) {
3993                         $count++;
3994                         if ( $count > $wgMaximumMovedPages ) {
3995                                 $retval[$oldSubpage->getPrefixedText()] = [
3996                                         [ 'movepage-max-pages', $wgMaximumMovedPages ],
3997                                 ];
3998                                 break;
3999                         }
4000
4001                         // We don't know whether this function was called before
4002                         // or after moving the root page, so check both
4003                         // $this and $nt
4004                         if ( $oldSubpage->getArticleID() == $this->getArticleID()
4005                                 || $oldSubpage->getArticleID() == $nt->getArticleID()
4006                         ) {
4007                                 // When moving a page to a subpage of itself,
4008                                 // don't move it twice
4009                                 continue;
4010                         }
4011                         $newPageName = preg_replace(
4012                                         '#^' . preg_quote( $this->getDBkey(), '#' ) . '#',
4013                                         StringUtils::escapeRegexReplacement( $nt->getDBkey() ), # T23234
4014                                         $oldSubpage->getDBkey() );
4015                         if ( $oldSubpage->isTalkPage() ) {
4016                                 $newNs = $nt->getTalkPage()->getNamespace();
4017                         } else {
4018                                 $newNs = $nt->getSubjectPage()->getNamespace();
4019                         }
4020                         # T16385: we need makeTitleSafe because the new page names may
4021                         # be longer than 255 characters.
4022                         $newSubpage = self::makeTitleSafe( $newNs, $newPageName );
4023
4024                         $success = $oldSubpage->moveTo( $newSubpage, $auth, $reason, $createRedirect, $changeTags );
4025                         if ( $success === true ) {
4026                                 $retval[$oldSubpage->getPrefixedText()] = $newSubpage->getPrefixedText();
4027                         } else {
4028                                 $retval[$oldSubpage->getPrefixedText()] = $success;
4029                         }
4030                 }
4031                 return $retval;
4032         }
4033
4034         /**
4035          * Checks if this page is just a one-rev redirect.
4036          * Adds lock, so don't use just for light purposes.
4037          *
4038          * @return bool
4039          */
4040         public function isSingleRevRedirect() {
4041                 global $wgContentHandlerUseDB;
4042
4043                 $dbw = wfGetDB( DB_MASTER );
4044
4045                 # Is it a redirect?
4046                 $fields = [ 'page_is_redirect', 'page_latest', 'page_id' ];
4047                 if ( $wgContentHandlerUseDB ) {
4048                         $fields[] = 'page_content_model';
4049                 }
4050
4051                 $row = $dbw->selectRow( 'page',
4052                         $fields,
4053                         $this->pageCond(),
4054                         __METHOD__,
4055                         [ 'FOR UPDATE' ]
4056                 );
4057                 # Cache some fields we may want
4058                 $this->mArticleID = $row ? intval( $row->page_id ) : 0;
4059                 $this->mRedirect = $row ? (bool)$row->page_is_redirect : false;
4060                 $this->mLatestID = $row ? intval( $row->page_latest ) : false;
4061                 $this->mContentModel = $row && isset( $row->page_content_model )
4062                         ? strval( $row->page_content_model )
4063                         : false;
4064
4065                 if ( !$this->mRedirect ) {
4066                         return false;
4067                 }
4068                 # Does the article have a history?
4069                 $row = $dbw->selectField( [ 'page', 'revision' ],
4070                         'rev_id',
4071                         [ 'page_namespace' => $this->getNamespace(),
4072                                 'page_title' => $this->getDBkey(),
4073                                 'page_id=rev_page',
4074                                 'page_latest != rev_id'
4075                         ],
4076                         __METHOD__,
4077                         [ 'FOR UPDATE' ]
4078                 );
4079                 # Return true if there was no history
4080                 return ( $row === false );
4081         }
4082
4083         /**
4084          * Checks if $this can be moved to a given Title
4085          * - Selects for update, so don't call it unless you mean business
4086          *
4087          * @deprecated since 1.25, use MovePage's methods instead
4088          * @param Title $nt The new title to check
4089          * @return bool
4090          */
4091         public function isValidMoveTarget( $nt ) {
4092                 # Is it an existing file?
4093                 if ( $nt->getNamespace() == NS_FILE ) {
4094                         $file = wfLocalFile( $nt );
4095                         $file->load( File::READ_LATEST );
4096                         if ( $file->exists() ) {
4097                                 wfDebug( __METHOD__ . ": file exists\n" );
4098                                 return false;
4099                         }
4100                 }
4101                 # Is it a redirect with no history?
4102                 if ( !$nt->isSingleRevRedirect() ) {
4103                         wfDebug( __METHOD__ . ": not a one-rev redirect\n" );
4104                         return false;
4105                 }
4106                 # Get the article text
4107                 $rev = Revision::newFromTitle( $nt, false, Revision::READ_LATEST );
4108                 if ( !is_object( $rev ) ) {
4109                         return false;
4110                 }
4111                 $content = $rev->getContent();
4112                 # Does the redirect point to the source?
4113                 # Or is it a broken self-redirect, usually caused by namespace collisions?
4114                 $redirTitle = $content ? $content->getRedirectTarget() : null;
4115
4116                 if ( $redirTitle ) {
4117                         if ( $redirTitle->getPrefixedDBkey() != $this->getPrefixedDBkey() &&
4118                                 $redirTitle->getPrefixedDBkey() != $nt->getPrefixedDBkey() ) {
4119                                 wfDebug( __METHOD__ . ": redirect points to other page\n" );
4120                                 return false;
4121                         } else {
4122                                 return true;
4123                         }
4124                 } else {
4125                         # Fail safe (not a redirect after all. strange.)
4126                         wfDebug( __METHOD__ . ": failsafe: database sais " . $nt->getPrefixedDBkey() .
4127                                                 " is a redirect, but it doesn't contain a valid redirect.\n" );
4128                         return false;
4129                 }
4130         }
4131
4132         /**
4133          * Get categories to which this Title belongs and return an array of
4134          * categories' names.
4135          *
4136          * @return array Array of parents in the form:
4137          *     $parent => $currentarticle
4138          */
4139         public function getParentCategories() {
4140                 global $wgContLang;
4141
4142                 $data = [];
4143
4144                 $titleKey = $this->getArticleID();
4145
4146                 if ( $titleKey === 0 ) {
4147                         return $data;
4148                 }
4149
4150                 $dbr = wfGetDB( DB_REPLICA );
4151
4152                 $res = $dbr->select(
4153                         'categorylinks',
4154                         'cl_to',
4155                         [ 'cl_from' => $titleKey ],
4156                         __METHOD__
4157                 );
4158
4159                 if ( $res->numRows() > 0 ) {
4160                         foreach ( $res as $row ) {
4161                                 // $data[] = Title::newFromText($wgContLang->getNsText ( NS_CATEGORY ).':'.$row->cl_to);
4162                                 $data[$wgContLang->getNsText( NS_CATEGORY ) . ':' . $row->cl_to] = $this->getFullText();
4163                         }
4164                 }
4165                 return $data;
4166         }
4167
4168         /**
4169          * Get a tree of parent categories
4170          *
4171          * @param array $children Array with the children in the keys, to check for circular refs
4172          * @return array Tree of parent categories
4173          */
4174         public function getParentCategoryTree( $children = [] ) {
4175                 $stack = [];
4176                 $parents = $this->getParentCategories();
4177
4178                 if ( $parents ) {
4179                         foreach ( $parents as $parent => $current ) {
4180                                 if ( array_key_exists( $parent, $children ) ) {
4181                                         # Circular reference
4182                                         $stack[$parent] = [];
4183                                 } else {
4184                                         $nt = self::newFromText( $parent );
4185                                         if ( $nt ) {
4186                                                 $stack[$parent] = $nt->getParentCategoryTree( $children + [ $parent => 1 ] );
4187                                         }
4188                                 }
4189                         }
4190                 }
4191
4192                 return $stack;
4193         }
4194
4195         /**
4196          * Get an associative array for selecting this title from
4197          * the "page" table
4198          *
4199          * @return array Array suitable for the $where parameter of DB::select()
4200          */
4201         public function pageCond() {
4202                 if ( $this->mArticleID > 0 ) {
4203                         // PK avoids secondary lookups in InnoDB, shouldn't hurt other DBs
4204                         return [ 'page_id' => $this->mArticleID ];
4205                 } else {
4206                         return [ 'page_namespace' => $this->mNamespace, 'page_title' => $this->mDbkeyform ];
4207                 }
4208         }
4209
4210         /**
4211          * Get next/previous revision ID relative to another revision ID
4212          * @param int $revId Revision ID. Get the revision that was before this one.
4213          * @param int $flags Title::GAID_FOR_UPDATE
4214          * @param string $dir 'next' or 'prev'
4215          * @return int|bool New revision ID, or false if none exists
4216          */
4217         private function getRelativeRevisionID( $revId, $flags, $dir ) {
4218                 $revId = (int)$revId;
4219                 if ( $dir === 'next' ) {
4220                         $op = '>';
4221                         $sort = 'ASC';
4222                 } elseif ( $dir === 'prev' ) {
4223                         $op = '<';
4224                         $sort = 'DESC';
4225                 } else {
4226                         throw new InvalidArgumentException( '$dir must be "next" or "prev"' );
4227                 }
4228
4229                 if ( $flags & self::GAID_FOR_UPDATE ) {
4230                         $db = wfGetDB( DB_MASTER );
4231                 } else {
4232                         $db = wfGetDB( DB_REPLICA, 'contributions' );
4233                 }
4234
4235                 // Intentionally not caring if the specified revision belongs to this
4236                 // page. We only care about the timestamp.
4237                 $ts = $db->selectField( 'revision', 'rev_timestamp', [ 'rev_id' => $revId ], __METHOD__ );
4238                 if ( $ts === false ) {
4239                         $ts = $db->selectField( 'archive', 'ar_timestamp', [ 'ar_rev_id' => $revId ], __METHOD__ );
4240                         if ( $ts === false ) {
4241                                 // Or should this throw an InvalidArgumentException or something?
4242                                 return false;
4243                         }
4244                 }
4245                 $ts = $db->addQuotes( $ts );
4246
4247                 $revId = $db->selectField( 'revision', 'rev_id',
4248                         [
4249                                 'rev_page' => $this->getArticleID( $flags ),
4250                                 "rev_timestamp $op $ts OR (rev_timestamp = $ts AND rev_id $op $revId)"
4251                         ],
4252                         __METHOD__,
4253                         [
4254                                 'ORDER BY' => "rev_timestamp $sort, rev_id $sort",
4255                                 'IGNORE INDEX' => 'rev_timestamp', // Probably needed for T159319
4256                         ]
4257                 );
4258
4259                 if ( $revId === false ) {
4260                         return false;
4261                 } else {
4262                         return intval( $revId );
4263                 }
4264         }
4265
4266         /**
4267          * Get the revision ID of the previous revision
4268          *
4269          * @param int $revId Revision ID. Get the revision that was before this one.
4270          * @param int $flags Title::GAID_FOR_UPDATE
4271          * @return int|bool Old revision ID, or false if none exists
4272          */
4273         public function getPreviousRevisionID( $revId, $flags = 0 ) {
4274                 return $this->getRelativeRevisionID( $revId, $flags, 'prev' );
4275         }
4276
4277         /**
4278          * Get the revision ID of the next revision
4279          *
4280          * @param int $revId Revision ID. Get the revision that was after this one.
4281          * @param int $flags Title::GAID_FOR_UPDATE
4282          * @return int|bool Next revision ID, or false if none exists
4283          */
4284         public function getNextRevisionID( $revId, $flags = 0 ) {
4285                 return $this->getRelativeRevisionID( $revId, $flags, 'next' );
4286         }
4287
4288         /**
4289          * Get the first revision of the page
4290          *
4291          * @param int $flags Title::GAID_FOR_UPDATE
4292          * @return Revision|null If page doesn't exist
4293          */
4294         public function getFirstRevision( $flags = 0 ) {
4295                 $pageId = $this->getArticleID( $flags );
4296                 if ( $pageId ) {
4297                         $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_REPLICA );
4298                         $revQuery = Revision::getQueryInfo();
4299                         $row = $db->selectRow( $revQuery['tables'], $revQuery['fields'],
4300                                 [ 'rev_page' => $pageId ],
4301                                 __METHOD__,
4302                                 [
4303                                         'ORDER BY' => 'rev_timestamp ASC, rev_id ASC',
4304                                         'IGNORE INDEX' => [ 'revision' => 'rev_timestamp' ], // See T159319
4305                                 ],
4306                                 $revQuery['joins']
4307                         );
4308                         if ( $row ) {
4309                                 return new Revision( $row );
4310                         }
4311                 }
4312                 return null;
4313         }
4314
4315         /**
4316          * Get the oldest revision timestamp of this page
4317          *
4318          * @param int $flags Title::GAID_FOR_UPDATE
4319          * @return string MW timestamp
4320          */
4321         public function getEarliestRevTime( $flags = 0 ) {
4322                 $rev = $this->getFirstRevision( $flags );
4323                 return $rev ? $rev->getTimestamp() : null;
4324         }
4325
4326         /**
4327          * Check if this is a new page
4328          *
4329          * @return bool
4330          */
4331         public function isNewPage() {
4332                 $dbr = wfGetDB( DB_REPLICA );
4333                 return (bool)$dbr->selectField( 'page', 'page_is_new', $this->pageCond(), __METHOD__ );
4334         }
4335
4336         /**
4337          * Check whether the number of revisions of this page surpasses $wgDeleteRevisionsLimit
4338          *
4339          * @return bool
4340          */
4341         public function isBigDeletion() {
4342                 global $wgDeleteRevisionsLimit;
4343
4344                 if ( !$wgDeleteRevisionsLimit ) {
4345                         return false;
4346                 }
4347
4348                 if ( $this->mIsBigDeletion === null ) {
4349                         $dbr = wfGetDB( DB_REPLICA );
4350
4351                         $revCount = $dbr->selectRowCount(
4352                                 'revision',
4353                                 '1',
4354                                 [ 'rev_page' => $this->getArticleID() ],
4355                                 __METHOD__,
4356                                 [ 'LIMIT' => $wgDeleteRevisionsLimit + 1 ]
4357                         );
4358
4359                         $this->mIsBigDeletion = $revCount > $wgDeleteRevisionsLimit;
4360                 }
4361
4362                 return $this->mIsBigDeletion;
4363         }
4364
4365         /**
4366          * Get the approximate revision count of this page.
4367          *
4368          * @return int
4369          */
4370         public function estimateRevisionCount() {
4371                 if ( !$this->exists() ) {
4372                         return 0;
4373                 }
4374
4375                 if ( $this->mEstimateRevisions === null ) {
4376                         $dbr = wfGetDB( DB_REPLICA );
4377                         $this->mEstimateRevisions = $dbr->estimateRowCount( 'revision', '*',
4378                                 [ 'rev_page' => $this->getArticleID() ], __METHOD__ );
4379                 }
4380
4381                 return $this->mEstimateRevisions;
4382         }
4383
4384         /**
4385          * Get the number of revisions between the given revision.
4386          * Used for diffs and other things that really need it.
4387          *
4388          * @param int|Revision $old Old revision or rev ID (first before range)
4389          * @param int|Revision $new New revision or rev ID (first after range)
4390          * @param int|null $max Limit of Revisions to count, will be incremented to detect truncations
4391          * @return int Number of revisions between these revisions.
4392          */
4393         public function countRevisionsBetween( $old, $new, $max = null ) {
4394                 if ( !( $old instanceof Revision ) ) {
4395                         $old = Revision::newFromTitle( $this, (int)$old );
4396                 }
4397                 if ( !( $new instanceof Revision ) ) {
4398                         $new = Revision::newFromTitle( $this, (int)$new );
4399                 }
4400                 if ( !$old || !$new ) {
4401                         return 0; // nothing to compare
4402                 }
4403                 $dbr = wfGetDB( DB_REPLICA );
4404                 $conds = [
4405                         'rev_page' => $this->getArticleID(),
4406                         'rev_timestamp > ' . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4407                         'rev_timestamp < ' . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4408                 ];
4409                 if ( $max !== null ) {
4410                         return $dbr->selectRowCount( 'revision', '1',
4411                                 $conds,
4412                                 __METHOD__,
4413                                 [ 'LIMIT' => $max + 1 ] // extra to detect truncation
4414                         );
4415                 } else {
4416                         return (int)$dbr->selectField( 'revision', 'count(*)', $conds, __METHOD__ );
4417                 }
4418         }
4419
4420         /**
4421          * Get the authors between the given revisions or revision IDs.
4422          * Used for diffs and other things that really need it.
4423          *
4424          * @since 1.23
4425          *
4426          * @param int|Revision $old Old revision or rev ID (first before range by default)
4427          * @param int|Revision $new New revision or rev ID (first after range by default)
4428          * @param int $limit Maximum number of authors
4429          * @param string|array $options (Optional): Single option, or an array of options:
4430          *     'include_old' Include $old in the range; $new is excluded.
4431          *     'include_new' Include $new in the range; $old is excluded.
4432          *     'include_both' Include both $old and $new in the range.
4433          *     Unknown option values are ignored.
4434          * @return array|null Names of revision authors in the range; null if not both revisions exist
4435          */
4436         public function getAuthorsBetween( $old, $new, $limit, $options = [] ) {
4437                 if ( !( $old instanceof Revision ) ) {
4438                         $old = Revision::newFromTitle( $this, (int)$old );
4439                 }
4440                 if ( !( $new instanceof Revision ) ) {
4441                         $new = Revision::newFromTitle( $this, (int)$new );
4442                 }
4443                 // XXX: what if Revision objects are passed in, but they don't refer to this title?
4444                 // Add $old->getPage() != $new->getPage() || $old->getPage() != $this->getArticleID()
4445                 // in the sanity check below?
4446                 if ( !$old || !$new ) {
4447                         return null; // nothing to compare
4448                 }
4449                 $authors = [];
4450                 $old_cmp = '>';
4451                 $new_cmp = '<';
4452                 $options = (array)$options;
4453                 if ( in_array( 'include_old', $options ) ) {
4454                         $old_cmp = '>=';
4455                 }
4456                 if ( in_array( 'include_new', $options ) ) {
4457                         $new_cmp = '<=';
4458                 }
4459                 if ( in_array( 'include_both', $options ) ) {
4460                         $old_cmp = '>=';
4461                         $new_cmp = '<=';
4462                 }
4463                 // No DB query needed if $old and $new are the same or successive revisions:
4464                 if ( $old->getId() === $new->getId() ) {
4465                         return ( $old_cmp === '>' && $new_cmp === '<' ) ?
4466                                 [] :
4467                                 [ $old->getUserText( Revision::RAW ) ];
4468                 } elseif ( $old->getId() === $new->getParentId() ) {
4469                         if ( $old_cmp === '>=' && $new_cmp === '<=' ) {
4470                                 $authors[] = $old->getUserText( Revision::RAW );
4471                                 if ( $old->getUserText( Revision::RAW ) != $new->getUserText( Revision::RAW ) ) {
4472                                         $authors[] = $new->getUserText( Revision::RAW );
4473                                 }
4474                         } elseif ( $old_cmp === '>=' ) {
4475                                 $authors[] = $old->getUserText( Revision::RAW );
4476                         } elseif ( $new_cmp === '<=' ) {
4477                                 $authors[] = $new->getUserText( Revision::RAW );
4478                         }
4479                         return $authors;
4480                 }
4481                 $dbr = wfGetDB( DB_REPLICA );
4482                 $revQuery = Revision::getQueryInfo();
4483                 $authors = $dbr->selectFieldValues(
4484                         $revQuery['tables'],
4485                         $revQuery['fields']['rev_user_text'],
4486                         [
4487                                 'rev_page' => $this->getArticleID(),
4488                                 "rev_timestamp $old_cmp " . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4489                                 "rev_timestamp $new_cmp " . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4490                         ], __METHOD__,
4491                         [ 'DISTINCT', 'LIMIT' => $limit + 1 ], // add one so caller knows it was truncated
4492                         $revQuery['joins']
4493                 );
4494                 return $authors;
4495         }
4496
4497         /**
4498          * Get the number of authors between the given revisions or revision IDs.
4499          * Used for diffs and other things that really need it.
4500          *
4501          * @param int|Revision $old Old revision or rev ID (first before range by default)
4502          * @param int|Revision $new New revision or rev ID (first after range by default)
4503          * @param int $limit Maximum number of authors
4504          * @param string|array $options (Optional): Single option, or an array of options:
4505          *     'include_old' Include $old in the range; $new is excluded.
4506          *     'include_new' Include $new in the range; $old is excluded.
4507          *     'include_both' Include both $old and $new in the range.
4508          *     Unknown option values are ignored.
4509          * @return int Number of revision authors in the range; zero if not both revisions exist
4510          */
4511         public function countAuthorsBetween( $old, $new, $limit, $options = [] ) {
4512                 $authors = $this->getAuthorsBetween( $old, $new, $limit, $options );
4513                 return $authors ? count( $authors ) : 0;
4514         }
4515
4516         /**
4517          * Compare with another title.
4518          *
4519          * @param Title $title
4520          * @return bool
4521          */
4522         public function equals( Title $title ) {
4523                 // Note: === is necessary for proper matching of number-like titles.
4524                 return $this->getInterwiki() === $title->getInterwiki()
4525                         && $this->getNamespace() == $title->getNamespace()
4526                         && $this->getDBkey() === $title->getDBkey();
4527         }
4528
4529         /**
4530          * Check if this title is a subpage of another title
4531          *
4532          * @param Title $title
4533          * @return bool
4534          */
4535         public function isSubpageOf( Title $title ) {
4536                 return $this->getInterwiki() === $title->getInterwiki()
4537                         && $this->getNamespace() == $title->getNamespace()
4538                         && strpos( $this->getDBkey(), $title->getDBkey() . '/' ) === 0;
4539         }
4540
4541         /**
4542          * Check if page exists.  For historical reasons, this function simply
4543          * checks for the existence of the title in the page table, and will
4544          * thus return false for interwiki links, special pages and the like.
4545          * If you want to know if a title can be meaningfully viewed, you should
4546          * probably call the isKnown() method instead.
4547          *
4548          * @param int $flags An optional bit field; may be Title::GAID_FOR_UPDATE to check
4549          *   from master/for update
4550          * @return bool
4551          */
4552         public function exists( $flags = 0 ) {
4553                 $exists = $this->getArticleID( $flags ) != 0;
4554                 Hooks::run( 'TitleExists', [ $this, &$exists ] );
4555                 return $exists;
4556         }
4557
4558         /**
4559          * Should links to this title be shown as potentially viewable (i.e. as
4560          * "bluelinks"), even if there's no record by this title in the page
4561          * table?
4562          *
4563          * This function is semi-deprecated for public use, as well as somewhat
4564          * misleadingly named.  You probably just want to call isKnown(), which
4565          * calls this function internally.
4566          *
4567          * (ISSUE: Most of these checks are cheap, but the file existence check
4568          * can potentially be quite expensive.  Including it here fixes a lot of
4569          * existing code, but we might want to add an optional parameter to skip
4570          * it and any other expensive checks.)
4571          *
4572          * @return bool
4573          */
4574         public function isAlwaysKnown() {
4575                 $isKnown = null;
4576
4577                 /**
4578                  * Allows overriding default behavior for determining if a page exists.
4579                  * If $isKnown is kept as null, regular checks happen. If it's
4580                  * a boolean, this value is returned by the isKnown method.
4581                  *
4582                  * @since 1.20
4583                  *
4584                  * @param Title $title
4585                  * @param bool|null $isKnown
4586                  */
4587                 Hooks::run( 'TitleIsAlwaysKnown', [ $this, &$isKnown ] );
4588
4589                 if ( !is_null( $isKnown ) ) {
4590                         return $isKnown;
4591                 }
4592
4593                 if ( $this->isExternal() ) {
4594                         return true; // any interwiki link might be viewable, for all we know
4595                 }
4596
4597                 switch ( $this->mNamespace ) {
4598                         case NS_MEDIA:
4599                         case NS_FILE:
4600                                 // file exists, possibly in a foreign repo
4601                                 return (bool)wfFindFile( $this );
4602                         case NS_SPECIAL:
4603                                 // valid special page
4604                                 return SpecialPageFactory::exists( $this->getDBkey() );
4605                         case NS_MAIN:
4606                                 // selflink, possibly with fragment
4607                                 return $this->mDbkeyform == '';
4608                         case NS_MEDIAWIKI:
4609                                 // known system message
4610                                 return $this->hasSourceText() !== false;
4611                         default:
4612                                 return false;
4613                 }
4614         }
4615
4616         /**
4617          * Does this title refer to a page that can (or might) be meaningfully
4618          * viewed?  In particular, this function may be used to determine if
4619          * links to the title should be rendered as "bluelinks" (as opposed to
4620          * "redlinks" to non-existent pages).
4621          * Adding something else to this function will cause inconsistency
4622          * since LinkHolderArray calls isAlwaysKnown() and does its own
4623          * page existence check.
4624          *
4625          * @return bool
4626          */
4627         public function isKnown() {
4628                 return $this->isAlwaysKnown() || $this->exists();
4629         }
4630
4631         /**
4632          * Does this page have source text?
4633          *
4634          * @return bool
4635          */
4636         public function hasSourceText() {
4637                 if ( $this->exists() ) {
4638                         return true;
4639                 }
4640
4641                 if ( $this->mNamespace == NS_MEDIAWIKI ) {
4642                         // If the page doesn't exist but is a known system message, default
4643                         // message content will be displayed, same for language subpages-
4644                         // Use always content language to avoid loading hundreds of languages
4645                         // to get the link color.
4646                         global $wgContLang;
4647                         list( $name, ) = MessageCache::singleton()->figureMessage(
4648                                 $wgContLang->lcfirst( $this->getText() )
4649                         );
4650                         $message = wfMessage( $name )->inLanguage( $wgContLang )->useDatabase( false );
4651                         return $message->exists();
4652                 }
4653
4654                 return false;
4655         }
4656
4657         /**
4658          * Get the default message text or false if the message doesn't exist
4659          *
4660          * @return string|bool
4661          */
4662         public function getDefaultMessageText() {
4663                 global $wgContLang;
4664
4665                 if ( $this->getNamespace() != NS_MEDIAWIKI ) { // Just in case
4666                         return false;
4667                 }
4668
4669                 list( $name, $lang ) = MessageCache::singleton()->figureMessage(
4670                         $wgContLang->lcfirst( $this->getText() )
4671                 );
4672                 $message = wfMessage( $name )->inLanguage( $lang )->useDatabase( false );
4673
4674                 if ( $message->exists() ) {
4675                         return $message->plain();
4676                 } else {
4677                         return false;
4678                 }
4679         }
4680
4681         /**
4682          * Updates page_touched for this page; called from LinksUpdate.php
4683          *
4684          * @param string $purgeTime [optional] TS_MW timestamp
4685          * @return bool True if the update succeeded
4686          */
4687         public function invalidateCache( $purgeTime = null ) {
4688                 if ( wfReadOnly() ) {
4689                         return false;
4690                 } elseif ( $this->mArticleID === 0 ) {
4691                         return true; // avoid gap locking if we know it's not there
4692                 }
4693
4694                 $dbw = wfGetDB( DB_MASTER );
4695                 $dbw->onTransactionPreCommitOrIdle(
4696                         function () {
4697                                 ResourceLoaderWikiModule::invalidateModuleCache( $this, null, null, wfWikiID() );
4698                         },
4699                         __METHOD__
4700                 );
4701
4702                 $conds = $this->pageCond();
4703                 DeferredUpdates::addUpdate(
4704                         new AutoCommitUpdate(
4705                                 $dbw,
4706                                 __METHOD__,
4707                                 function ( IDatabase $dbw, $fname ) use ( $conds, $purgeTime ) {
4708                                         $dbTimestamp = $dbw->timestamp( $purgeTime ?: time() );
4709                                         $dbw->update(
4710                                                 'page',
4711                                                 [ 'page_touched' => $dbTimestamp ],
4712                                                 $conds + [ 'page_touched < ' . $dbw->addQuotes( $dbTimestamp ) ],
4713                                                 $fname
4714                                         );
4715                                         MediaWikiServices::getInstance()->getLinkCache()->invalidateTitle( $this );
4716                                 }
4717                         ),
4718                         DeferredUpdates::PRESEND
4719                 );
4720
4721                 return true;
4722         }
4723
4724         /**
4725          * Update page_touched timestamps and send CDN purge messages for
4726          * pages linking to this title. May be sent to the job queue depending
4727          * on the number of links. Typically called on create and delete.
4728          */
4729         public function touchLinks() {
4730                 DeferredUpdates::addUpdate( new HTMLCacheUpdate( $this, 'pagelinks', 'page-touch' ) );
4731                 if ( $this->getNamespace() == NS_CATEGORY ) {
4732                         DeferredUpdates::addUpdate(
4733                                 new HTMLCacheUpdate( $this, 'categorylinks', 'category-touch' )
4734                         );
4735                 }
4736         }
4737
4738         /**
4739          * Get the last touched timestamp
4740          *
4741          * @param IDatabase|null $db
4742          * @return string|false Last-touched timestamp
4743          */
4744         public function getTouched( $db = null ) {
4745                 if ( $db === null ) {
4746                         $db = wfGetDB( DB_REPLICA );
4747                 }
4748                 $touched = $db->selectField( 'page', 'page_touched', $this->pageCond(), __METHOD__ );
4749                 return $touched;
4750         }
4751
4752         /**
4753          * Get the timestamp when this page was updated since the user last saw it.
4754          *
4755          * @param User $user
4756          * @return string|null
4757          */
4758         public function getNotificationTimestamp( $user = null ) {
4759                 global $wgUser;
4760
4761                 // Assume current user if none given
4762                 if ( !$user ) {
4763                         $user = $wgUser;
4764                 }
4765                 // Check cache first
4766                 $uid = $user->getId();
4767                 if ( !$uid ) {
4768                         return false;
4769                 }
4770                 // avoid isset here, as it'll return false for null entries
4771                 if ( array_key_exists( $uid, $this->mNotificationTimestamp ) ) {
4772                         return $this->mNotificationTimestamp[$uid];
4773                 }
4774                 // Don't cache too much!
4775                 if ( count( $this->mNotificationTimestamp ) >= self::CACHE_MAX ) {
4776                         $this->mNotificationTimestamp = [];
4777                 }
4778
4779                 $store = MediaWikiServices::getInstance()->getWatchedItemStore();
4780                 $watchedItem = $store->getWatchedItem( $user, $this );
4781                 if ( $watchedItem ) {
4782                         $this->mNotificationTimestamp[$uid] = $watchedItem->getNotificationTimestamp();
4783                 } else {
4784                         $this->mNotificationTimestamp[$uid] = false;
4785                 }
4786
4787                 return $this->mNotificationTimestamp[$uid];
4788         }
4789
4790         /**
4791          * Generate strings used for xml 'id' names in monobook tabs
4792          *
4793          * @param string $prepend Defaults to 'nstab-'
4794          * @return string XML 'id' name
4795          */
4796         public function getNamespaceKey( $prepend = 'nstab-' ) {
4797                 global $wgContLang;
4798                 // Gets the subject namespace of this title
4799                 $subjectNS = MWNamespace::getSubject( $this->getNamespace() );
4800                 // Prefer canonical namespace name for HTML IDs
4801                 $namespaceKey = MWNamespace::getCanonicalName( $subjectNS );
4802                 if ( $namespaceKey === false ) {
4803                         // Fallback to localised text
4804                         $namespaceKey = $this->getSubjectNsText();
4805                 }
4806                 // Makes namespace key lowercase
4807                 $namespaceKey = $wgContLang->lc( $namespaceKey );
4808                 // Uses main
4809                 if ( $namespaceKey == '' ) {
4810                         $namespaceKey = 'main';
4811                 }
4812                 // Changes file to image for backwards compatibility
4813                 if ( $namespaceKey == 'file' ) {
4814                         $namespaceKey = 'image';
4815                 }
4816                 return $prepend . $namespaceKey;
4817         }
4818
4819         /**
4820          * Get all extant redirects to this Title
4821          *
4822          * @param int|null $ns Single namespace to consider; null to consider all namespaces
4823          * @return Title[] Array of Title redirects to this title
4824          */
4825         public function getRedirectsHere( $ns = null ) {
4826                 $redirs = [];
4827
4828                 $dbr = wfGetDB( DB_REPLICA );
4829                 $where = [
4830                         'rd_namespace' => $this->getNamespace(),
4831                         'rd_title' => $this->getDBkey(),
4832                         'rd_from = page_id'
4833                 ];
4834                 if ( $this->isExternal() ) {
4835                         $where['rd_interwiki'] = $this->getInterwiki();
4836                 } else {
4837                         $where[] = 'rd_interwiki = ' . $dbr->addQuotes( '' ) . ' OR rd_interwiki IS NULL';
4838                 }
4839                 if ( !is_null( $ns ) ) {
4840                         $where['page_namespace'] = $ns;
4841                 }
4842
4843                 $res = $dbr->select(
4844                         [ 'redirect', 'page' ],
4845                         [ 'page_namespace', 'page_title' ],
4846                         $where,
4847                         __METHOD__
4848                 );
4849
4850                 foreach ( $res as $row ) {
4851                         $redirs[] = self::newFromRow( $row );
4852                 }
4853                 return $redirs;
4854         }
4855
4856         /**
4857          * Check if this Title is a valid redirect target
4858          *
4859          * @return bool
4860          */
4861         public function isValidRedirectTarget() {
4862                 global $wgInvalidRedirectTargets;
4863
4864                 if ( $this->isSpecialPage() ) {
4865                         // invalid redirect targets are stored in a global array, but explicitly disallow Userlogout here
4866                         if ( $this->isSpecial( 'Userlogout' ) ) {
4867                                 return false;
4868                         }
4869
4870                         foreach ( $wgInvalidRedirectTargets as $target ) {
4871                                 if ( $this->isSpecial( $target ) ) {
4872                                         return false;
4873                                 }
4874                         }
4875                 }
4876
4877                 return true;
4878         }
4879
4880         /**
4881          * Get a backlink cache object
4882          *
4883          * @return BacklinkCache
4884          */
4885         public function getBacklinkCache() {
4886                 return BacklinkCache::get( $this );
4887         }
4888
4889         /**
4890          * Whether the magic words __INDEX__ and __NOINDEX__ function for this page.
4891          *
4892          * @return bool
4893          */
4894         public function canUseNoindex() {
4895                 global $wgExemptFromUserRobotsControl;
4896
4897                 $bannedNamespaces = is_null( $wgExemptFromUserRobotsControl )
4898                         ? MWNamespace::getContentNamespaces()
4899                         : $wgExemptFromUserRobotsControl;
4900
4901                 return !in_array( $this->mNamespace, $bannedNamespaces );
4902         }
4903
4904         /**
4905          * Returns the raw sort key to be used for categories, with the specified
4906          * prefix.  This will be fed to Collation::getSortKey() to get a
4907          * binary sortkey that can be used for actual sorting.
4908          *
4909          * @param string $prefix The prefix to be used, specified using
4910          *   {{defaultsort:}} or like [[Category:Foo|prefix]].  Empty for no
4911          *   prefix.
4912          * @return string
4913          */
4914         public function getCategorySortkey( $prefix = '' ) {
4915                 $unprefixed = $this->getText();
4916
4917                 // Anything that uses this hook should only depend
4918                 // on the Title object passed in, and should probably
4919                 // tell the users to run updateCollations.php --force
4920                 // in order to re-sort existing category relations.
4921                 Hooks::run( 'GetDefaultSortkey', [ $this, &$unprefixed ] );
4922                 if ( $prefix !== '' ) {
4923                         # Separate with a line feed, so the unprefixed part is only used as
4924                         # a tiebreaker when two pages have the exact same prefix.
4925                         # In UCA, tab is the only character that can sort above LF
4926                         # so we strip both of them from the original prefix.
4927                         $prefix = strtr( $prefix, "\n\t", '  ' );
4928                         return "$prefix\n$unprefixed";
4929                 }
4930                 return $unprefixed;
4931         }
4932
4933         /**
4934          * Returns the page language code saved in the database, if $wgPageLanguageUseDB is set
4935          * to true in LocalSettings.php, otherwise returns false. If there is no language saved in
4936          * the db, it will return NULL.
4937          *
4938          * @return string|null|bool
4939          */
4940         private function getDbPageLanguageCode() {
4941                 global $wgPageLanguageUseDB;
4942
4943                 // check, if the page language could be saved in the database, and if so and
4944                 // the value is not requested already, lookup the page language using LinkCache
4945                 if ( $wgPageLanguageUseDB && $this->mDbPageLanguage === false ) {
4946                         $linkCache = MediaWikiServices::getInstance()->getLinkCache();
4947                         $linkCache->addLinkObj( $this );
4948                         $this->mDbPageLanguage = $linkCache->getGoodLinkFieldObj( $this, 'lang' );
4949                 }
4950
4951                 return $this->mDbPageLanguage;
4952         }
4953
4954         /**
4955          * Get the language in which the content of this page is written in
4956          * wikitext. Defaults to $wgContLang, but in certain cases it can be
4957          * e.g. $wgLang (such as special pages, which are in the user language).
4958          *
4959          * @since 1.18
4960          * @return Language
4961          */
4962         public function getPageLanguage() {
4963                 global $wgLang, $wgLanguageCode;
4964                 if ( $this->isSpecialPage() ) {
4965                         // special pages are in the user language
4966                         return $wgLang;
4967                 }
4968
4969                 // Checking if DB language is set
4970                 $dbPageLanguage = $this->getDbPageLanguageCode();
4971                 if ( $dbPageLanguage ) {
4972                         return wfGetLangObj( $dbPageLanguage );
4973                 }
4974
4975                 if ( !$this->mPageLanguage || $this->mPageLanguage[1] !== $wgLanguageCode ) {
4976                         // Note that this may depend on user settings, so the cache should
4977                         // be only per-request.
4978                         // NOTE: ContentHandler::getPageLanguage() may need to load the
4979                         // content to determine the page language!
4980                         // Checking $wgLanguageCode hasn't changed for the benefit of unit
4981                         // tests.
4982                         $contentHandler = ContentHandler::getForTitle( $this );
4983                         $langObj = $contentHandler->getPageLanguage( $this );
4984                         $this->mPageLanguage = [ $langObj->getCode(), $wgLanguageCode ];
4985                 } else {
4986                         $langObj = Language::factory( $this->mPageLanguage[0] );
4987                 }
4988
4989                 return $langObj;
4990         }
4991
4992         /**
4993          * Get the language in which the content of this page is written when
4994          * viewed by user. Defaults to $wgContLang, but in certain cases it can be
4995          * e.g. $wgLang (such as special pages, which are in the user language).
4996          *
4997          * @since 1.20
4998          * @return Language
4999          */
5000         public function getPageViewLanguage() {
5001                 global $wgLang;
5002
5003                 if ( $this->isSpecialPage() ) {
5004                         // If the user chooses a variant, the content is actually
5005                         // in a language whose code is the variant code.
5006                         $variant = $wgLang->getPreferredVariant();
5007                         if ( $wgLang->getCode() !== $variant ) {
5008                                 return Language::factory( $variant );
5009                         }
5010
5011                         return $wgLang;
5012                 }
5013
5014                 // Checking if DB language is set
5015                 $dbPageLanguage = $this->getDbPageLanguageCode();
5016                 if ( $dbPageLanguage ) {
5017                         $pageLang = wfGetLangObj( $dbPageLanguage );
5018                         $variant = $pageLang->getPreferredVariant();
5019                         if ( $pageLang->getCode() !== $variant ) {
5020                                 $pageLang = Language::factory( $variant );
5021                         }
5022
5023                         return $pageLang;
5024                 }
5025
5026                 // @note Can't be cached persistently, depends on user settings.
5027                 // @note ContentHandler::getPageViewLanguage() may need to load the
5028                 //   content to determine the page language!
5029                 $contentHandler = ContentHandler::getForTitle( $this );
5030                 $pageLang = $contentHandler->getPageViewLanguage( $this );
5031                 return $pageLang;
5032         }
5033
5034         /**
5035          * Get a list of rendered edit notices for this page.
5036          *
5037          * Array is keyed by the original message key, and values are rendered using parseAsBlock, so
5038          * they will already be wrapped in paragraphs.
5039          *
5040          * @since 1.21
5041          * @param int $oldid Revision ID that's being edited
5042          * @return array
5043          */
5044         public function getEditNotices( $oldid = 0 ) {
5045                 $notices = [];
5046
5047                 // Optional notice for the entire namespace
5048                 $editnotice_ns = 'editnotice-' . $this->getNamespace();
5049                 $msg = wfMessage( $editnotice_ns );
5050                 if ( $msg->exists() ) {
5051                         $html = $msg->parseAsBlock();
5052                         // Edit notices may have complex logic, but output nothing (T91715)
5053                         if ( trim( $html ) !== '' ) {
5054                                 $notices[$editnotice_ns] = Html::rawElement(
5055                                         'div',
5056                                         [ 'class' => [
5057                                                 'mw-editnotice',
5058                                                 'mw-editnotice-namespace',
5059                                                 Sanitizer::escapeClass( "mw-$editnotice_ns" )
5060                                         ] ],
5061                                         $html
5062                                 );
5063                         }
5064                 }
5065
5066                 if ( MWNamespace::hasSubpages( $this->getNamespace() ) ) {
5067                         // Optional notice for page itself and any parent page
5068                         $parts = explode( '/', $this->getDBkey() );
5069                         $editnotice_base = $editnotice_ns;
5070                         while ( count( $parts ) > 0 ) {
5071                                 $editnotice_base .= '-' . array_shift( $parts );
5072                                 $msg = wfMessage( $editnotice_base );
5073                                 if ( $msg->exists() ) {
5074                                         $html = $msg->parseAsBlock();
5075                                         if ( trim( $html ) !== '' ) {
5076                                                 $notices[$editnotice_base] = Html::rawElement(
5077                                                         'div',
5078                                                         [ 'class' => [
5079                                                                 'mw-editnotice',
5080                                                                 'mw-editnotice-base',
5081                                                                 Sanitizer::escapeClass( "mw-$editnotice_base" )
5082                                                         ] ],
5083                                                         $html
5084                                                 );
5085                                         }
5086                                 }
5087                         }
5088                 } else {
5089                         // Even if there are no subpages in namespace, we still don't want "/" in MediaWiki message keys
5090                         $editnoticeText = $editnotice_ns . '-' . strtr( $this->getDBkey(), '/', '-' );
5091                         $msg = wfMessage( $editnoticeText );
5092                         if ( $msg->exists() ) {
5093                                 $html = $msg->parseAsBlock();
5094                                 if ( trim( $html ) !== '' ) {
5095                                         $notices[$editnoticeText] = Html::rawElement(
5096                                                 'div',
5097                                                 [ 'class' => [
5098                                                         'mw-editnotice',
5099                                                         'mw-editnotice-page',
5100                                                         Sanitizer::escapeClass( "mw-$editnoticeText" )
5101                                                 ] ],
5102                                                 $html
5103                                         );
5104                                 }
5105                         }
5106                 }
5107
5108                 Hooks::run( 'TitleGetEditNotices', [ $this, $oldid, &$notices ] );
5109                 return $notices;
5110         }
5111
5112         /**
5113          * @return array
5114          */
5115         public function __sleep() {
5116                 return [
5117                         'mNamespace',
5118                         'mDbkeyform',
5119                         'mFragment',
5120                         'mInterwiki',
5121                         'mLocalInterwiki',
5122                         'mUserCaseDBKey',
5123                         'mDefaultNamespace',
5124                 ];
5125         }
5126
5127         public function __wakeup() {
5128                 $this->mArticleID = ( $this->mNamespace >= 0 ) ? -1 : 0;
5129                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
5130                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
5131         }
5132
5133 }