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, IDBAccessObject {
  40         /** @var MapCacheLRU */
  41         private static $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         /**
 138          * Text form including namespace/interwiki, initialised on demand
 139          *
 140          * Only public to share cache with TitleFormatter
 141          *
 142          * @private
 143          * @var string
 144          */
 145         public $prefixedText = null;
 146
 147         /** @var mixed Cached value for getTitleProtection (create protection) */
 148         public $mTitleProtection;
 149
 150         /**
 151          * @var int Namespace index when there is no namespace. Don't change the
 152          *   following default, NS_MAIN is hardcoded in several places. See T2696.
 153          *   Zero except in {{transclusion}} tags.
 154          */
 155         public $mDefaultNamespace = NS_MAIN;
 156
 157         /** @var int The page length, 0 for special pages */
 158         protected $mLength = -1;
 159
 160         /** @var null Is the article at this title a redirect? */
 161         public $mRedirect = null;
 162
 163         /** @var array Associative array of user ID -> timestamp/false */
 164         private $mNotificationTimestamp = [];
 165
 166         /** @var bool Whether a page has any subpages */
 167         private $mHasSubpages;
 168
 169         /** @var bool The (string) language code of the page's language and content code. */
 170         private $mPageLanguage = false;
 171
 172         /** @var string|bool|null The page language code from the database, null if not saved in
 173          * the database or false if not loaded, yet. */
 174         private $mDbPageLanguage = false;
 175
 176         /** @var TitleValue A corresponding TitleValue object */
 177         private $mTitleValue = null;
 178
 179         /** @var bool Would deleting this page be a big deletion? */
 180         private $mIsBigDeletion = null;
 181         // @}
 182
 183         /**
 184          * B/C kludge: provide a TitleParser for use by Title.
 185          * Ideally, Title would have no methods that need this.
 186          * Avoid usage of this singleton by using TitleValue
 187          * and the associated services when possible.
 188          *
 189          * @return TitleFormatter
 190          */
 191         private static function getTitleFormatter() {
 192                 return MediaWikiServices::getInstance()->getTitleFormatter();
 193         }
 194
 195         /**
 196          * B/C kludge: provide an InterwikiLookup for use by Title.
 197          * Ideally, Title would have no methods that need this.
 198          * Avoid usage of this singleton by using TitleValue
 199          * and the associated services when possible.
 200          *
 201          * @return InterwikiLookup
 202          */
 203         private static function getInterwikiLookup() {
 204                 return MediaWikiServices::getInstance()->getInterwikiLookup();
 205         }
 206
 207         /**
 208          * @protected
 209          */
 210         function __construct() {
 211         }
 212
 213         /**
 214          * Create a new Title from a prefixed DB key
 215          *
 216          * @param string $key The database key, which has underscores
 217          *      instead of spaces, possibly including namespace and
 218          *      interwiki prefixes
 219          * @return Title|null Title, or null on an error
 220          */
 221         public static function newFromDBkey( $key ) {
 222                 $t = new Title();
 223                 $t->mDbkeyform = $key;
 224
 225                 try {
 226                         $t->secureAndSplit();
 227                         return $t;
 228                 } catch ( MalformedTitleException $ex ) {
 229                         return null;
 230                 }
 231         }
 232
 233         /**
 234          * Create a new Title from a TitleValue
 235          *
 236          * @param TitleValue $titleValue Assumed to be safe.
 237          *
 238          * @return Title
 239          */
 240         public static function newFromTitleValue( TitleValue $titleValue ) {
 241                 return self::newFromLinkTarget( $titleValue );
 242         }
 243
 244         /**
 245          * Create a new Title from a LinkTarget
 246          *
 247          * @param LinkTarget $linkTarget Assumed to be safe.
 248          *
 249          * @return Title
 250          */
 251         public static function newFromLinkTarget( LinkTarget $linkTarget ) {
 252                 if ( $linkTarget instanceof Title ) {
 253                         // Special case if it's already a Title object
 254                         return $linkTarget;
 255                 }
 256                 return self::makeTitle(
 257                         $linkTarget->getNamespace(),
 258                         $linkTarget->getText(),
 259                         $linkTarget->getFragment(),
 260                         $linkTarget->getInterwiki()
 261                 );
 262         }
 263
 264         /**
 265          * Create a new Title from text, such as what one would find in a link. De-
 266          * codes any HTML entities in the text.
 267          *
 268          * Title objects returned by this method are guaranteed to be valid, and
 269          * thus return true from the isValid() method.
 270          *
 271          * @param string|int|null $text The link text; spaces, prefixes, and an
 272          *   initial ':' indicating the main namespace are accepted.
 273          * @param int $defaultNamespace The namespace to use if none is specified
 274          *   by a prefix.  If you want to force a specific namespace even if
 275          *   $text might begin with a namespace prefix, use makeTitle() or
 276          *   makeTitleSafe().
 277          * @throws InvalidArgumentException
 278          * @return Title|null Title or null on an error.
 279          */
 280         public static function newFromText( $text, $defaultNamespace = NS_MAIN ) {
 281                 // DWIM: Integers can be passed in here when page titles are used as array keys.
 282                 if ( $text !== null && !is_string( $text ) && !is_int( $text ) ) {
 283                         throw new InvalidArgumentException( '$text must be a string.' );
 284                 }
 285                 if ( $text === null ) {
 286                         return null;
 287                 }
 288
 289                 try {
 290                         return self::newFromTextThrow( strval( $text ), $defaultNamespace );
 291                 } catch ( MalformedTitleException $ex ) {
 292                         return null;
 293                 }
 294         }
 295
 296         /**
 297          * Like Title::newFromText(), but throws MalformedTitleException when the title is invalid,
 298          * rather than returning null.
 299          *
 300          * The exception subclasses encode detailed information about why the title is invalid.
 301          *
 302          * Title objects returned by this method are guaranteed to be valid, and
 303          * thus return true from the isValid() method.
 304          *
 305          * @see Title::newFromText
 306          *
 307          * @since 1.25
 308          * @param string $text Title text to check
 309          * @param int $defaultNamespace
 310          * @throws MalformedTitleException If the title is invalid
 311          * @return Title
 312          */
 313         public static function newFromTextThrow( $text, $defaultNamespace = NS_MAIN ) {
 314                 if ( is_object( $text ) ) {
 315                         throw new MWException( '$text must be a string, given an object' );
 316                 } elseif ( $text === null ) {
 317                         // Legacy code relies on MalformedTitleException being thrown in this case
 318                         // (happens when URL with no title in it is parsed). TODO fix
 319                         throw new MalformedTitleException( 'title-invalid-empty' );
 320                 }
 321
 322                 $titleCache = self::getTitleCache();
 323
 324                 // Wiki pages often contain multiple links to the same page.
 325                 // Title normalization and parsing can become expensive on pages with many
 326                 // links, so we can save a little time by caching them.
 327                 // In theory these are value objects and won't get changed...
 328                 if ( $defaultNamespace == NS_MAIN ) {
 329                         $t = $titleCache->get( $text );
 330                         if ( $t ) {
 331                                 return $t;
 332                         }
 333                 }
 334
 335                 // Convert things like &eacute; &#257; or &#x3017; into normalized (T16952) text
 336                 $filteredText = Sanitizer::decodeCharReferencesAndNormalize( $text );
 337
 338                 $t = new Title();
 339                 $t->mDbkeyform = strtr( $filteredText, ' ', '_' );
 340                 $t->mDefaultNamespace = intval( $defaultNamespace );
 341
 342                 $t->secureAndSplit();
 343                 if ( $defaultNamespace == NS_MAIN ) {
 344                         $titleCache->set( $text, $t );
 345                 }
 346                 return $t;
 347         }
 348
 349         /**
 350          * THIS IS NOT THE FUNCTION YOU WANT. Use Title::newFromText().
 351          *
 352          * Example of wrong and broken code:
 353          * $title = Title::newFromURL( $wgRequest->getVal( 'title' ) );
 354          *
 355          * Example of right code:
 356          * $title = Title::newFromText( $wgRequest->getVal( 'title' ) );
 357          *
 358          * Create a new Title from URL-encoded text. Ensures that
 359          * the given title's length does not exceed the maximum.
 360          *
 361          * @param string $url The title, as might be taken from a URL
 362          * @return Title|null The new object, or null on an error
 363          */
 364         public static function newFromURL( $url ) {
 365                 $t = new Title();
 366
 367                 # For compatibility with old buggy URLs. "+" is usually not valid in titles,
 368                 # but some URLs used it as a space replacement and they still come
 369                 # from some external search tools.
 370                 if ( strpos( self::legalChars(), '+' ) === false ) {
 371                         $url = strtr( $url, '+', ' ' );
 372                 }
 373
 374                 $t->mDbkeyform = strtr( $url, ' ', '_' );
 375
 376                 try {
 377                         $t->secureAndSplit();
 378                         return $t;
 379                 } catch ( MalformedTitleException $ex ) {
 380                         return null;
 381                 }
 382         }
 383
 384         /**
 385          * @return MapCacheLRU
 386          */
 387         private static function getTitleCache() {
 388                 if ( self::$titleCache == null ) {
 389                         self::$titleCache = new MapCacheLRU( self::CACHE_MAX );
 390                 }
 391                 return self::$titleCache;
 392         }
 393
 394         /**
 395          * Returns a list of fields that are to be selected for initializing Title
 396          * objects or LinkCache entries. Uses $wgContentHandlerUseDB to determine
 397          * whether to include page_content_model.
 398          *
 399          * @return array
 400          */
 401         protected static function getSelectFields() {
 402                 global $wgContentHandlerUseDB, $wgPageLanguageUseDB;
 403
 404                 $fields = [
 405                         'page_namespace', 'page_title', 'page_id',
 406                         'page_len', 'page_is_redirect', 'page_latest',
 407                 ];
 408
 409                 if ( $wgContentHandlerUseDB ) {
 410                         $fields[] = 'page_content_model';
 411                 }
 412
 413                 if ( $wgPageLanguageUseDB ) {
 414                         $fields[] = 'page_lang';
 415                 }
 416
 417                 return $fields;
 418         }
 419
 420         /**
 421          * Create a new Title from an article ID
 422          *
 423          * @param int $id The page_id corresponding to the Title to create
 424          * @param int $flags Use Title::GAID_FOR_UPDATE to use master
 425          * @return Title|null The new object, or null on an error
 426          */
 427         public static function newFromID( $id, $flags = 0 ) {
 428                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_REPLICA );
 429                 $row = $db->selectRow(
 430                         'page',
 431                         self::getSelectFields(),
 432                         [ 'page_id' => $id ],
 433                         __METHOD__
 434                 );
 435                 if ( $row !== false ) {
 436                         $title = self::newFromRow( $row );
 437                 } else {
 438                         $title = null;
 439                 }
 440                 return $title;
 441         }
 442
 443         /**
 444          * Make an array of titles from an array of IDs
 445          *
 446          * @param int[] $ids Array of IDs
 447          * @return Title[] Array of Titles
 448          */
 449         public static function newFromIDs( $ids ) {
 450                 if ( !count( $ids ) ) {
 451                         return [];
 452                 }
 453                 $dbr = wfGetDB( DB_REPLICA );
 454
 455                 $res = $dbr->select(
 456                         'page',
 457                         self::getSelectFields(),
 458                         [ 'page_id' => $ids ],
 459                         __METHOD__
 460                 );
 461
 462                 $titles = [];
 463                 foreach ( $res as $row ) {
 464                         $titles[] = self::newFromRow( $row );
 465                 }
 466                 return $titles;
 467         }
 468
 469         /**
 470          * Make a Title object from a DB row
 471          *
 472          * @param stdClass $row Object database row (needs at least page_title,page_namespace)
 473          * @return Title Corresponding Title
 474          */
 475         public static function newFromRow( $row ) {
 476                 $t = self::makeTitle( $row->page_namespace, $row->page_title );
 477                 $t->loadFromRow( $row );
 478                 return $t;
 479         }
 480
 481         /**
 482          * Load Title object fields from a DB row.
 483          * If false is given, the title will be treated as non-existing.
 484          *
 485          * @param stdClass|bool $row Database row
 486          */
 487         public function loadFromRow( $row ) {
 488                 if ( $row ) { // page found
 489                         if ( isset( $row->page_id ) ) {
 490                                 $this->mArticleID = (int)$row->page_id;
 491                         }
 492                         if ( isset( $row->page_len ) ) {
 493                                 $this->mLength = (int)$row->page_len;
 494                         }
 495                         if ( isset( $row->page_is_redirect ) ) {
 496                                 $this->mRedirect = (bool)$row->page_is_redirect;
 497                         }
 498                         if ( isset( $row->page_latest ) ) {
 499                                 $this->mLatestID = (int)$row->page_latest;
 500                         }
 501                         if ( !$this->mForcedContentModel && isset( $row->page_content_model ) ) {
 502                                 $this->mContentModel = strval( $row->page_content_model );
 503                         } elseif ( !$this->mForcedContentModel ) {
 504                                 $this->mContentModel = false; # initialized lazily in getContentModel()
 505                         }
 506                         if ( isset( $row->page_lang ) ) {
 507                                 $this->mDbPageLanguage = (string)$row->page_lang;
 508                         }
 509                         if ( isset( $row->page_restrictions ) ) {
 510                                 $this->mOldRestrictions = $row->page_restrictions;
 511                         }
 512                 } else { // page not found
 513                         $this->mArticleID = 0;
 514                         $this->mLength = 0;
 515                         $this->mRedirect = false;
 516                         $this->mLatestID = 0;
 517                         if ( !$this->mForcedContentModel ) {
 518                                 $this->mContentModel = false; # initialized lazily in getContentModel()
 519                         }
 520                 }
 521         }
 522
 523         /**
 524          * Create a new Title from a namespace index and a DB key.
 525          *
 526          * It's assumed that $ns and $title are safe, for instance when
 527          * they came directly from the database or a special page name,
 528          * not from user input.
 529          *
 530          * No validation is applied. For convenience, spaces are normalized
 531          * to underscores, so that e.g. user_text fields can be used directly.
 532          *
 533          * @note This method may return Title objects that are "invalid"
 534          * according to the isValid() method. This is usually caused by
 535          * configuration changes: e.g. a namespace that was once defined is
 536          * no longer configured, or a character that was once allowed in
 537          * titles is now forbidden.
 538          *
 539          * @param int $ns The namespace of the article
 540          * @param string $title The unprefixed database key form
 541          * @param string $fragment The link fragment (after the "#")
 542          * @param string $interwiki The interwiki prefix
 543          * @return Title The new object
 544          */
 545         public static function makeTitle( $ns, $title, $fragment = '', $interwiki = '' ) {
 546                 $t = new Title();
 547                 $t->mInterwiki = $interwiki;
 548                 $t->mFragment = $fragment;
 549                 $t->mNamespace = $ns = intval( $ns );
 550                 $t->mDbkeyform = strtr( $title, ' ', '_' );
 551                 $t->mArticleID = ( $ns >= 0 ) ? -1 : 0;
 552                 $t->mUrlform = wfUrlencode( $t->mDbkeyform );
 553                 $t->mTextform = strtr( $title, '_', ' ' );
 554                 $t->mContentModel = false; # initialized lazily in getContentModel()
 555                 return $t;
 556         }
 557
 558         /**
 559          * Create a new Title from a namespace index and a DB key.
 560          * The parameters will be checked for validity, which is a bit slower
 561          * than makeTitle() but safer for user-provided data.
 562          *
 563          * Title objects returned by makeTitleSafe() are guaranteed to be valid,
 564          * that is, they return true from the isValid() method. If no valid Title
 565          * can be constructed from the input, this method returns null.
 566          *
 567          * @param int $ns The namespace of the article
 568          * @param string $title Database key form
 569          * @param string $fragment The link fragment (after the "#")
 570          * @param string $interwiki Interwiki prefix
 571          * @return Title|null The new object, or null on an error
 572          */
 573         public static function makeTitleSafe( $ns, $title, $fragment = '', $interwiki = '' ) {
 574                 // NOTE: ideally, this would just call makeTitle() and then isValid(),
 575                 // but presently, that means more overhead on a potential performance hotspot.
 576
 577                 if ( !MWNamespace::exists( $ns ) ) {
 578                         return null;
 579                 }
 580
 581                 $t = new Title();
 582                 $t->mDbkeyform = self::makeName( $ns, $title, $fragment, $interwiki, true );
 583
 584                 try {
 585                         $t->secureAndSplit();
 586                         return $t;
 587                 } catch ( MalformedTitleException $ex ) {
 588                         return null;
 589                 }
 590         }
 591
 592         /**
 593          * Create a new Title for the Main Page
 594          *
 595          * @return Title The new object
 596          */
 597         public static function newMainPage() {
 598                 $title = self::newFromText( wfMessage( 'mainpage' )->inContentLanguage()->text() );
 599                 // Don't give fatal errors if the message is broken
 600                 if ( !$title ) {
 601                         $title = self::newFromText( 'Main Page' );
 602                 }
 603                 return $title;
 604         }
 605
 606         /**
 607          * Get the prefixed DB key associated with an ID
 608          *
 609          * @param int $id The page_id of the article
 610          * @return Title|null An object representing the article, or null if no such article was found
 611          */
 612         public static function nameOf( $id ) {
 613                 $dbr = wfGetDB( DB_REPLICA );
 614
 615                 $s = $dbr->selectRow(
 616                         'page',
 617                         [ 'page_namespace', 'page_title' ],
 618                         [ 'page_id' => $id ],
 619                         __METHOD__
 620                 );
 621                 if ( $s === false ) {
 622                         return null;
 623                 }
 624
 625                 $n = self::makeName( $s->page_namespace, $s->page_title );
 626                 return $n;
 627         }
 628
 629         /**
 630          * Get a regex character class describing the legal characters in a link
 631          *
 632          * @return string The list of characters, not delimited
 633          */
 634         public static function legalChars() {
 635                 global $wgLegalTitleChars;
 636                 return $wgLegalTitleChars;
 637         }
 638
 639         /**
 640          * Utility method for converting a character sequence from bytes to Unicode.
 641          *
 642          * Primary usecase being converting $wgLegalTitleChars to a sequence usable in
 643          * javascript, as PHP uses UTF-8 bytes where javascript uses Unicode code units.
 644          *
 645          * @param string $byteClass
 646          * @return string
 647          */
 648         public static function convertByteClassToUnicodeClass( $byteClass ) {
 649                 $length = strlen( $byteClass );
 650                 // Input token queue
 651                 $x0 = $x1 = $x2 = '';
 652                 // Decoded queue
 653                 $d0 = $d1 = $d2 = '';
 654                 // Decoded integer codepoints
 655                 $ord0 = $ord1 = $ord2 = 0;
 656                 // Re-encoded queue
 657                 $r0 = $r1 = $r2 = '';
 658                 // Output
 659                 $out = '';
 660                 // Flags
 661                 $allowUnicode = false;
 662                 for ( $pos = 0; $pos < $length; $pos++ ) {
 663                         // Shift the queues down
 664                         $x2 = $x1;
 665                         $x1 = $x0;
 666                         $d2 = $d1;
 667                         $d1 = $d0;
 668                         $ord2 = $ord1;
 669                         $ord1 = $ord0;
 670                         $r2 = $r1;
 671                         $r1 = $r0;
 672                         // Load the current input token and decoded values
 673                         $inChar = $byteClass[$pos];
 674                         if ( $inChar == '\\' ) {
 675                                 if ( preg_match( '/x([0-9a-fA-F]{2})/A', $byteClass, $m, 0, $pos + 1 ) ) {
 676                                         $x0 = $inChar . $m[0];
 677                                         $d0 = chr( hexdec( $m[1] ) );
 678                                         $pos += strlen( $m[0] );
 679                                 } elseif ( preg_match( '/[0-7]{3}/A', $byteClass, $m, 0, $pos + 1 ) ) {
 680                                         $x0 = $inChar . $m[0];
 681                                         $d0 = chr( octdec( $m[0] ) );
 682                                         $pos += strlen( $m[0] );
 683                                 } elseif ( $pos + 1 >= $length ) {
 684                                         $x0 = $d0 = '\\';
 685                                 } else {
 686                                         $d0 = $byteClass[$pos + 1];
 687                                         $x0 = $inChar . $d0;
 688                                         $pos += 1;
 689                                 }
 690                         } else {
 691                                 $x0 = $d0 = $inChar;
 692                         }
 693                         $ord0 = ord( $d0 );
 694                         // Load the current re-encoded value
 695                         if ( $ord0 < 32 || $ord0 == 0x7f ) {
 696                                 $r0 = sprintf( '\x%02x', $ord0 );
 697                         } elseif ( $ord0 >= 0x80 ) {
 698                                 // Allow unicode if a single high-bit character appears
 699                                 $r0 = sprintf( '\x%02x', $ord0 );
 700                                 $allowUnicode = true;
 701                         } elseif ( strpos( '-\\[]^', $d0 ) !== false ) {
 702                                 $r0 = '\\' . $d0;
 703                         } else {
 704                                 $r0 = $d0;
 705                         }
 706                         // Do the output
 707                         if ( $x0 !== '' && $x1 === '-' && $x2 !== '' ) {
 708                                 // Range
 709                                 if ( $ord2 > $ord0 ) {
 710                                         // Empty range
 711                                 } elseif ( $ord0 >= 0x80 ) {
 712                                         // Unicode range
 713                                         $allowUnicode = true;
 714                                         if ( $ord2 < 0x80 ) {
 715                                                 // Keep the non-unicode section of the range
 716                                                 $out .= "$r2-\\x7F";
 717                                         }
 718                                 } else {
 719                                         // Normal range
 720                                         $out .= "$r2-$r0";
 721                                 }
 722                                 // Reset state to the initial value
 723                                 $x0 = $x1 = $d0 = $d1 = $r0 = $r1 = '';
 724                         } elseif ( $ord2 < 0x80 ) {
 725                                 // ASCII character
 726                                 $out .= $r2;
 727                         }
 728                 }
 729                 if ( $ord1 < 0x80 ) {
 730                         $out .= $r1;
 731                 }
 732                 if ( $ord0 < 0x80 ) {
 733                         $out .= $r0;
 734                 }
 735                 if ( $allowUnicode ) {
 736                         $out .= '\u0080-\uFFFF';
 737                 }
 738                 return $out;
 739         }
 740
 741         /**
 742          * Make a prefixed DB key from a DB key and a namespace index
 743          *
 744          * @param int $ns Numerical representation of the namespace
 745          * @param string $title The DB key form the title
 746          * @param string $fragment The link fragment (after the "#")
 747          * @param string $interwiki The interwiki prefix
 748          * @param bool $canonicalNamespace If true, use the canonical name for
 749          *   $ns instead of the localized version.
 750          * @return string The prefixed form of the title
 751          */
 752         public static function makeName( $ns, $title, $fragment = '', $interwiki = '',
 753                 $canonicalNamespace = false
 754         ) {
 755                 if ( $canonicalNamespace ) {
 756                         $namespace = MWNamespace::getCanonicalName( $ns );
 757                 } else {
 758                         $namespace = MediaWikiServices::getInstance()->getContentLanguage()->getNsText( $ns );
 759                 }
 760                 $name = $namespace == '' ? $title : "$namespace:$title";
 761                 if ( strval( $interwiki ) != '' ) {
 762                         $name = "$interwiki:$name";
 763                 }
 764                 if ( strval( $fragment ) != '' ) {
 765                         $name .= '#' . $fragment;
 766                 }
 767                 return $name;
 768         }
 769
 770         /**
 771          * Callback for usort() to do title sorts by (namespace, title)
 772          *
 773          * @param LinkTarget $a
 774          * @param LinkTarget $b
 775          *
 776          * @return int Result of string comparison, or namespace comparison
 777          */
 778         public static function compare( LinkTarget $a, LinkTarget $b ) {
 779                 return $a->getNamespace() <=> $b->getNamespace()
 780                         ?: strcmp( $a->getText(), $b->getText() );
 781         }
 782
 783         /**
 784          * Returns true if the title is valid, false if it is invalid.
 785          *
 786          * Valid titles can be round-tripped via makeTitleSafe() and newFromText().
 787          * Invalid titles may get returned from makeTitle(), and it may be useful to
 788          * allow them to exist, e.g. in order to process log entries about pages in
 789          * namespaces that belong to extensions that are no longer installed.
 790          *
 791          * @note This method is relatively expensive. When constructing Title
 792          * objects that need to be valid, use an instantiator method that is guaranteed
 793          * to return valid titles, such as makeTitleSafe() or newFromText().
 794          *
 795          * @return bool
 796          */
 797         public function isValid() {
 798                 if ( !MWNamespace::exists( $this->mNamespace ) ) {
 799                         return false;
 800                 }
 801
 802                 try {
 803                         $parser = MediaWikiServices::getInstance()->getTitleParser();
 804                         $parser->parseTitle( $this->mDbkeyform, $this->mNamespace );
 805                         return true;
 806                 } catch ( MalformedTitleException $ex ) {
 807                         return false;
 808                 }
 809         }
 810
 811         /**
 812          * Determine whether the object refers to a page within
 813          * this project (either this wiki or a wiki with a local
 814          * interwiki, see https://www.mediawiki.org/wiki/Manual:Interwiki_table#iw_local )
 815          *
 816          * @return bool True if this is an in-project interwiki link or a wikilink, false otherwise
 817          */
 818         public function isLocal() {
 819                 if ( $this->isExternal() ) {
 820                         $iw = self::getInterwikiLookup()->fetch( $this->mInterwiki );
 821                         if ( $iw ) {
 822                                 return $iw->isLocal();
 823                         }
 824                 }
 825                 return true;
 826         }
 827
 828         /**
 829          * Is this Title interwiki?
 830          *
 831          * @return bool
 832          */
 833         public function isExternal() {
 834                 return $this->mInterwiki !== '';
 835         }
 836
 837         /**
 838          * Get the interwiki prefix
 839          *
 840          * Use Title::isExternal to check if a interwiki is set
 841          *
 842          * @return string Interwiki prefix
 843          */
 844         public function getInterwiki() {
 845                 return $this->mInterwiki;
 846         }
 847
 848         /**
 849          * Was this a local interwiki link?
 850          *
 851          * @return bool
 852          */
 853         public function wasLocalInterwiki() {
 854                 return $this->mLocalInterwiki;
 855         }
 856
 857         /**
 858          * Determine whether the object refers to a page within
 859          * this project and is transcludable.
 860          *
 861          * @return bool True if this is transcludable
 862          */
 863         public function isTrans() {
 864                 if ( !$this->isExternal() ) {
 865                         return false;
 866                 }
 867
 868                 return self::getInterwikiLookup()->fetch( $this->mInterwiki )->isTranscludable();
 869         }
 870
 871         /**
 872          * Returns the DB name of the distant wiki which owns the object.
 873          *
 874          * @return string|false The DB name
 875          */
 876         public function getTransWikiID() {
 877                 if ( !$this->isExternal() ) {
 878                         return false;
 879                 }
 880
 881                 return self::getInterwikiLookup()->fetch( $this->mInterwiki )->getWikiID();
 882         }
 883
 884         /**
 885          * Get a TitleValue object representing this Title.
 886          *
 887          * @note Not all valid Titles have a corresponding valid TitleValue
 888          * (e.g. TitleValues cannot represent page-local links that have a
 889          * fragment but no title text).
 890          *
 891          * @return TitleValue|null
 892          */
 893         public function getTitleValue() {
 894                 if ( $this->mTitleValue === null ) {
 895                         try {
 896                                 $this->mTitleValue = new TitleValue(
 897                                         $this->mNamespace,
 898                                         $this->mDbkeyform,
 899                                         $this->mFragment,
 900                                         $this->mInterwiki
 901                                 );
 902                         } catch ( InvalidArgumentException $ex ) {
 903                                 wfDebug( __METHOD__ . ': Can\'t create a TitleValue for [[' .
 904                                         $this->getPrefixedText() . ']]: ' . $ex->getMessage() . "\n" );
 905                         }
 906                 }
 907
 908                 return $this->mTitleValue;
 909         }
 910
 911         /**
 912          * Get the text form (spaces not underscores) of the main part
 913          *
 914          * @return string Main part of the title
 915          */
 916         public function getText() {
 917                 return $this->mTextform;
 918         }
 919
 920         /**
 921          * Get the URL-encoded form of the main part
 922          *
 923          * @return string Main part of the title, URL-encoded
 924          */
 925         public function getPartialURL() {
 926                 return $this->mUrlform;
 927         }
 928
 929         /**
 930          * Get the main part with underscores
 931          *
 932          * @return string Main part of the title, with underscores
 933          */
 934         public function getDBkey() {
 935                 return $this->mDbkeyform;
 936         }
 937
 938         /**
 939          * Get the DB key with the initial letter case as specified by the user
 940          * @deprecated since 1.33; please use Title::getDBKey() instead
 941          *
 942          * @return string DB key
 943          */
 944         function getUserCaseDBKey() {
 945                 if ( !is_null( $this->mUserCaseDBKey ) ) {
 946                         return $this->mUserCaseDBKey;
 947                 } else {
 948                         // If created via makeTitle(), $this->mUserCaseDBKey is not set.
 949                         return $this->mDbkeyform;
 950                 }
 951         }
 952
 953         /**
 954          * Get the namespace index, i.e. one of the NS_xxxx constants.
 955          *
 956          * @return int Namespace index
 957          */
 958         public function getNamespace() {
 959                 return $this->mNamespace;
 960         }
 961
 962         /**
 963          * Get the page's content model id, see the CONTENT_MODEL_XXX constants.
 964          *
 965          * @todo Deprecate this in favor of SlotRecord::getModel()
 966          *
 967          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
 968          * @return string Content model id
 969          */
 970         public function getContentModel( $flags = 0 ) {
 971                 if ( !$this->mForcedContentModel
 972                         && ( !$this->mContentModel || $flags === self::GAID_FOR_UPDATE )
 973                         && $this->getArticleID( $flags )
 974                 ) {
 975                         $linkCache = MediaWikiServices::getInstance()->getLinkCache();
 976                         $linkCache->addLinkObj( $this ); # in case we already had an article ID
 977                         $this->mContentModel = $linkCache->getGoodLinkFieldObj( $this, 'model' );
 978                 }
 979
 980                 if ( !$this->mContentModel ) {
 981                         $this->mContentModel = ContentHandler::getDefaultModelFor( $this );
 982                 }
 983
 984                 return $this->mContentModel;
 985         }
 986
 987         /**
 988          * Convenience method for checking a title's content model name
 989          *
 990          * @param string $id The content model ID (use the CONTENT_MODEL_XXX constants).
 991          * @return bool True if $this->getContentModel() == $id
 992          */
 993         public function hasContentModel( $id ) {
 994                 return $this->getContentModel() == $id;
 995         }
 996
 997         /**
 998          * Set a proposed content model for the page for permissions
 999          * checking. This does not actually change the content model
1000          * of a title!
1001          *
1002          * Additionally, you should make sure you've checked
1003          * ContentHandler::canBeUsedOn() first.
1004          *
1005          * @since 1.28
1006          * @param string $model CONTENT_MODEL_XXX constant
1007          */
1008         public function setContentModel( $model ) {
1009                 $this->mContentModel = $model;
1010                 $this->mForcedContentModel = true;
1011         }
1012
1013         /**
1014          * Get the namespace text
1015          *
1016          * @return string|false Namespace text
1017          */
1018         public function getNsText() {
1019                 if ( $this->isExternal() ) {
1020                         // This probably shouldn't even happen, except for interwiki transclusion.
1021                         // If possible, use the canonical name for the foreign namespace.
1022                         $nsText = MWNamespace::getCanonicalName( $this->mNamespace );
1023                         if ( $nsText !== false ) {
1024                                 return $nsText;
1025                         }
1026                 }
1027
1028                 try {
1029                         $formatter = self::getTitleFormatter();
1030                         return $formatter->getNamespaceName( $this->mNamespace, $this->mDbkeyform );
1031                 } catch ( InvalidArgumentException $ex ) {
1032                         wfDebug( __METHOD__ . ': ' . $ex->getMessage() . "\n" );
1033                         return false;
1034                 }
1035         }
1036
1037         /**
1038          * Get the namespace text of the subject (rather than talk) page
1039          *
1040          * @return string Namespace text
1041          */
1042         public function getSubjectNsText() {
1043                 return MediaWikiServices::getInstance()->getContentLanguage()->
1044                         getNsText( MWNamespace::getSubject( $this->mNamespace ) );
1045         }
1046
1047         /**
1048          * Get the namespace text of the talk page
1049          *
1050          * @return string Namespace text
1051          */
1052         public function getTalkNsText() {
1053                 return MediaWikiServices::getInstance()->getContentLanguage()->
1054                         getNsText( MWNamespace::getTalk( $this->mNamespace ) );
1055         }
1056
1057         /**
1058          * Can this title have a corresponding talk page?
1059          *
1060          * @see MWNamespace::hasTalkNamespace
1061          * @since 1.30
1062          *
1063          * @return bool True if this title either is a talk page or can have a talk page associated.
1064          */
1065         public function canHaveTalkPage() {
1066                 return MWNamespace::hasTalkNamespace( $this->mNamespace );
1067         }
1068
1069         /**
1070          * Is this in a namespace that allows actual pages?
1071          *
1072          * @return bool
1073          */
1074         public function canExist() {
1075                 return $this->mNamespace >= NS_MAIN;
1076         }
1077
1078         /**
1079          * Can this title be added to a user's watchlist?
1080          *
1081          * @return bool
1082          */
1083         public function isWatchable() {
1084                 return !$this->isExternal() && MWNamespace::isWatchable( $this->mNamespace );
1085         }
1086
1087         /**
1088          * Returns true if this is a special page.
1089          *
1090          * @return bool
1091          */
1092         public function isSpecialPage() {
1093                 return $this->mNamespace == NS_SPECIAL;
1094         }
1095
1096         /**
1097          * Returns true if this title resolves to the named special page
1098          *
1099          * @param string $name The special page name
1100          * @return bool
1101          */
1102         public function isSpecial( $name ) {
1103                 if ( $this->isSpecialPage() ) {
1104                         list( $thisName, /* $subpage */ ) =
1105                                 MediaWikiServices::getInstance()->getSpecialPageFactory()->
1106                                         resolveAlias( $this->mDbkeyform );
1107                         if ( $name == $thisName ) {
1108                                 return true;
1109                         }
1110                 }
1111                 return false;
1112         }
1113
1114         /**
1115          * If the Title refers to a special page alias which is not the local default, resolve
1116          * the alias, and localise the name as necessary.  Otherwise, return $this
1117          *
1118          * @return Title
1119          */
1120         public function fixSpecialName() {
1121                 if ( $this->isSpecialPage() ) {
1122                         $spFactory = MediaWikiServices::getInstance()->getSpecialPageFactory();
1123                         list( $canonicalName, $par ) = $spFactory->resolveAlias( $this->mDbkeyform );
1124                         if ( $canonicalName ) {
1125                                 $localName = $spFactory->getLocalNameFor( $canonicalName, $par );
1126                                 if ( $localName != $this->mDbkeyform ) {
1127                                         return self::makeTitle( NS_SPECIAL, $localName );
1128                                 }
1129                         }
1130                 }
1131                 return $this;
1132         }
1133
1134         /**
1135          * Returns true if the title is inside the specified namespace.
1136          *
1137          * Please make use of this instead of comparing to getNamespace()
1138          * This function is much more resistant to changes we may make
1139          * to namespaces than code that makes direct comparisons.
1140          * @param int $ns The namespace
1141          * @return bool
1142          * @since 1.19
1143          */
1144         public function inNamespace( $ns ) {
1145                 return MWNamespace::equals( $this->mNamespace, $ns );
1146         }
1147
1148         /**
1149          * Returns true if the title is inside one of the specified namespaces.
1150          *
1151          * @param int|int[] $namespaces,... The namespaces to check for
1152          * @return bool
1153          * @since 1.19
1154          */
1155         public function inNamespaces( /* ... */ ) {
1156                 $namespaces = func_get_args();
1157                 if ( count( $namespaces ) > 0 && is_array( $namespaces[0] ) ) {
1158                         $namespaces = $namespaces[0];
1159                 }
1160
1161                 foreach ( $namespaces as $ns ) {
1162                         if ( $this->inNamespace( $ns ) ) {
1163                                 return true;
1164                         }
1165                 }
1166
1167                 return false;
1168         }
1169
1170         /**
1171          * Returns true if the title has the same subject namespace as the
1172          * namespace specified.
1173          * For example this method will take NS_USER and return true if namespace
1174          * is either NS_USER or NS_USER_TALK since both of them have NS_USER
1175          * as their subject namespace.
1176          *
1177          * This is MUCH simpler than individually testing for equivalence
1178          * against both NS_USER and NS_USER_TALK, and is also forward compatible.
1179          * @since 1.19
1180          * @param int $ns
1181          * @return bool
1182          */
1183         public function hasSubjectNamespace( $ns ) {
1184                 return MWNamespace::subjectEquals( $this->mNamespace, $ns );
1185         }
1186
1187         /**
1188          * Is this Title in a namespace which contains content?
1189          * In other words, is this a content page, for the purposes of calculating
1190          * statistics, etc?
1191          *
1192          * @return bool
1193          */
1194         public function isContentPage() {
1195                 return MWNamespace::isContent( $this->mNamespace );
1196         }
1197
1198         /**
1199          * Would anybody with sufficient privileges be able to move this page?
1200          * Some pages just aren't movable.
1201          *
1202          * @return bool
1203          */
1204         public function isMovable() {
1205                 if ( !MWNamespace::isMovable( $this->mNamespace ) || $this->isExternal() ) {
1206                         // Interwiki title or immovable namespace. Hooks don't get to override here
1207                         return false;
1208                 }
1209
1210                 $result = true;
1211                 Hooks::run( 'TitleIsMovable', [ $this, &$result ] );
1212                 return $result;
1213         }
1214
1215         /**
1216          * Is this the mainpage?
1217          * @note Title::newFromText seems to be sufficiently optimized by the title
1218          * cache that we don't need to over-optimize by doing direct comparisons and
1219          * accidentally creating new bugs where $title->equals( Title::newFromText() )
1220          * ends up reporting something differently than $title->isMainPage();
1221          *
1222          * @since 1.18
1223          * @return bool
1224          */
1225         public function isMainPage() {
1226                 return $this->equals( self::newMainPage() );
1227         }
1228
1229         /**
1230          * Is this a subpage?
1231          *
1232          * @return bool
1233          */
1234         public function isSubpage() {
1235                 return MWNamespace::hasSubpages( $this->mNamespace )
1236                         ? strpos( $this->getText(), '/' ) !== false
1237                         : false;
1238         }
1239
1240         /**
1241          * Is this a conversion table for the LanguageConverter?
1242          *
1243          * @return bool
1244          */
1245         public function isConversionTable() {
1246                 // @todo ConversionTable should become a separate content model.
1247
1248                 return $this->mNamespace == NS_MEDIAWIKI &&
1249                         strpos( $this->getText(), 'Conversiontable/' ) === 0;
1250         }
1251
1252         /**
1253          * Does that page contain wikitext, or it is JS, CSS or whatever?
1254          *
1255          * @return bool
1256          */
1257         public function isWikitextPage() {
1258                 return $this->hasContentModel( CONTENT_MODEL_WIKITEXT );
1259         }
1260
1261         /**
1262          * Could this MediaWiki namespace page contain custom CSS, JSON, or JavaScript for the
1263          * global UI. This is generally true for pages in the MediaWiki namespace having
1264          * CONTENT_MODEL_CSS, CONTENT_MODEL_JSON, or CONTENT_MODEL_JAVASCRIPT.
1265          *
1266          * This method does *not* return true for per-user JS/JSON/CSS. Use isUserConfigPage()
1267          * for that!
1268          *
1269          * Note that this method should not return true for pages that contain and show
1270          * "inactive" CSS, JSON, or JS.
1271          *
1272          * @return bool
1273          * @since 1.31
1274          */
1275         public function isSiteConfigPage() {
1276                 return (
1277                         $this->isSiteCssConfigPage()
1278                         || $this->isSiteJsonConfigPage()
1279                         || $this->isSiteJsConfigPage()
1280                 );
1281         }
1282
1283         /**
1284          * Is this a "config" (.css, .json, or .js) sub-page of a user page?
1285          *
1286          * @return bool
1287          * @since 1.31
1288          */
1289         public function isUserConfigPage() {
1290                 return (
1291                         $this->isUserCssConfigPage()
1292                         || $this->isUserJsonConfigPage()
1293                         || $this->isUserJsConfigPage()
1294                 );
1295         }
1296
1297         /**
1298          * Trim down a .css, .json, or .js subpage title to get the corresponding skin name
1299          *
1300          * @return string Containing skin name from .css, .json, or .js subpage title
1301          * @since 1.31
1302          */
1303         public function getSkinFromConfigSubpage() {
1304                 $subpage = explode( '/', $this->mTextform );
1305                 $subpage = $subpage[count( $subpage ) - 1];
1306                 $lastdot = strrpos( $subpage, '.' );
1307                 if ( $lastdot === false ) {
1308                         return $subpage; # Never happens: only called for names ending in '.css'/'.json'/'.js'
1309                 }
1310                 return substr( $subpage, 0, $lastdot );
1311         }
1312
1313         /**
1314          * Is this a CSS "config" sub-page of a user page?
1315          *
1316          * @return bool
1317          * @since 1.31
1318          */
1319         public function isUserCssConfigPage() {
1320                 return (
1321                         NS_USER == $this->mNamespace
1322                         && $this->isSubpage()
1323                         && $this->hasContentModel( CONTENT_MODEL_CSS )
1324                 );
1325         }
1326
1327         /**
1328          * Is this a JSON "config" sub-page of a user page?
1329          *
1330          * @return bool
1331          * @since 1.31
1332          */
1333         public function isUserJsonConfigPage() {
1334                 return (
1335                         NS_USER == $this->mNamespace
1336                         && $this->isSubpage()
1337                         && $this->hasContentModel( CONTENT_MODEL_JSON )
1338                 );
1339         }
1340
1341         /**
1342          * Is this a JS "config" sub-page of a user page?
1343          *
1344          * @return bool
1345          * @since 1.31
1346          */
1347         public function isUserJsConfigPage() {
1348                 return (
1349                         NS_USER == $this->mNamespace
1350                         && $this->isSubpage()
1351                         && $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT )
1352                 );
1353         }
1354
1355         /**
1356          * Is this a sitewide CSS "config" page?
1357          *
1358          * @return bool
1359          * @since 1.32
1360          */
1361         public function isSiteCssConfigPage() {
1362                 return (
1363                         NS_MEDIAWIKI == $this->mNamespace
1364                         && (
1365                                 $this->hasContentModel( CONTENT_MODEL_CSS )
1366                                 // paranoia - a MediaWiki: namespace page with mismatching extension and content
1367                                 // model is probably by mistake and might get handled incorrectly (see e.g. T112937)
1368                                 || substr( $this->mDbkeyform, -4 ) === '.css'
1369                         )
1370                 );
1371         }
1372
1373         /**
1374          * Is this a sitewide JSON "config" page?
1375          *
1376          * @return bool
1377          * @since 1.32
1378          */
1379         public function isSiteJsonConfigPage() {
1380                 return (
1381                         NS_MEDIAWIKI == $this->mNamespace
1382                         && (
1383                                 $this->hasContentModel( CONTENT_MODEL_JSON )
1384                                 // paranoia - a MediaWiki: namespace page with mismatching extension and content
1385                                 // model is probably by mistake and might get handled incorrectly (see e.g. T112937)
1386                                 || substr( $this->mDbkeyform, -5 ) === '.json'
1387                         )
1388                 );
1389         }
1390
1391         /**
1392          * Is this a sitewide JS "config" page?
1393          *
1394          * @return bool
1395          * @since 1.31
1396          */
1397         public function isSiteJsConfigPage() {
1398                 return (
1399                         NS_MEDIAWIKI == $this->mNamespace
1400                         && (
1401                                 $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT )
1402                                 // paranoia - a MediaWiki: namespace page with mismatching extension and content
1403                                 // model is probably by mistake and might get handled incorrectly (see e.g. T112937)
1404                                 || substr( $this->mDbkeyform, -3 ) === '.js'
1405                         )
1406                 );
1407         }
1408
1409         /**
1410          * Is this a message which can contain raw HTML?
1411          *
1412          * @return bool
1413          * @since 1.32
1414          */
1415         public function isRawHtmlMessage() {
1416                 global $wgRawHtmlMessages;
1417
1418                 if ( !$this->inNamespace( NS_MEDIAWIKI ) ) {
1419                         return false;
1420                 }
1421                 $message = lcfirst( $this->getRootTitle()->getDBkey() );
1422                 return in_array( $message, $wgRawHtmlMessages, true );
1423         }
1424
1425         /**
1426          * Is this a talk page of some sort?
1427          *
1428          * @return bool
1429          */
1430         public function isTalkPage() {
1431                 return MWNamespace::isTalk( $this->mNamespace );
1432         }
1433
1434         /**
1435          * Get a Title object associated with the talk page of this article
1436          *
1437          * @return Title The object for the talk page
1438          */
1439         public function getTalkPage() {
1440                 return self::makeTitle( MWNamespace::getTalk( $this->mNamespace ), $this->mDbkeyform );
1441         }
1442
1443         /**
1444          * Get a Title object associated with the talk page of this article,
1445          * if such a talk page can exist.
1446          *
1447          * @since 1.30
1448          *
1449          * @return Title|null The object for the talk page,
1450          *         or null if no associated talk page can exist, according to canHaveTalkPage().
1451          */
1452         public function getTalkPageIfDefined() {
1453                 if ( !$this->canHaveTalkPage() ) {
1454                         return null;
1455                 }
1456
1457                 return $this->getTalkPage();
1458         }
1459
1460         /**
1461          * Get a title object associated with the subject page of this
1462          * talk page
1463          *
1464          * @return Title The object for the subject page
1465          */
1466         public function getSubjectPage() {
1467                 // Is this the same title?
1468                 $subjectNS = MWNamespace::getSubject( $this->mNamespace );
1469                 if ( $this->mNamespace == $subjectNS ) {
1470                         return $this;
1471                 }
1472                 return self::makeTitle( $subjectNS, $this->mDbkeyform );
1473         }
1474
1475         /**
1476          * Get the other title for this page, if this is a subject page
1477          * get the talk page, if it is a subject page get the talk page
1478          *
1479          * @since 1.25
1480          * @throws MWException If the page doesn't have an other page
1481          * @return Title
1482          */
1483         public function getOtherPage() {
1484                 if ( $this->isSpecialPage() ) {
1485                         throw new MWException( 'Special pages cannot have other pages' );
1486                 }
1487                 if ( $this->isTalkPage() ) {
1488                         return $this->getSubjectPage();
1489                 } else {
1490                         if ( !$this->canHaveTalkPage() ) {
1491                                 throw new MWException( "{$this->getPrefixedText()} does not have an other page" );
1492                         }
1493                         return $this->getTalkPage();
1494                 }
1495         }
1496
1497         /**
1498          * Get the default namespace index, for when there is no namespace
1499          *
1500          * @return int Default namespace index
1501          */
1502         public function getDefaultNamespace() {
1503                 return $this->mDefaultNamespace;
1504         }
1505
1506         /**
1507          * Get the Title fragment (i.e.\ the bit after the #) in text form
1508          *
1509          * Use Title::hasFragment to check for a fragment
1510          *
1511          * @return string Title fragment
1512          */
1513         public function getFragment() {
1514                 return $this->mFragment;
1515         }
1516
1517         /**
1518          * Check if a Title fragment is set
1519          *
1520          * @return bool
1521          * @since 1.23
1522          */
1523         public function hasFragment() {
1524                 return $this->mFragment !== '';
1525         }
1526
1527         /**
1528          * Get the fragment in URL form, including the "#" character if there is one
1529          *
1530          * @return string Fragment in URL form
1531          */
1532         public function getFragmentForURL() {
1533                 if ( !$this->hasFragment() ) {
1534                         return '';
1535                 } elseif ( $this->isExternal() ) {
1536                         // Note: If the interwiki is unknown, it's treated as a namespace on the local wiki,
1537                         // so we treat it like a local interwiki.
1538                         $interwiki = self::getInterwikiLookup()->fetch( $this->mInterwiki );
1539                         if ( $interwiki && !$interwiki->isLocal() ) {
1540                                 return '#' . Sanitizer::escapeIdForExternalInterwiki( $this->mFragment );
1541                         }
1542                 }
1543
1544                 return '#' . Sanitizer::escapeIdForLink( $this->mFragment );
1545         }
1546
1547         /**
1548          * Set the fragment for this title. Removes the first character from the
1549          * specified fragment before setting, so it assumes you're passing it with
1550          * an initial "#".
1551          *
1552          * Deprecated for public use, use Title::makeTitle() with fragment parameter,
1553          * or Title::createFragmentTarget().
1554          * Still in active use privately.
1555          *
1556          * @private
1557          * @param string $fragment Text
1558          */
1559         public function setFragment( $fragment ) {
1560                 $this->mFragment = strtr( substr( $fragment, 1 ), '_', ' ' );
1561         }
1562
1563         /**
1564          * Creates a new Title for a different fragment of the same page.
1565          *
1566          * @since 1.27
1567          * @param string $fragment
1568          * @return Title
1569          */
1570         public function createFragmentTarget( $fragment ) {
1571                 return self::makeTitle(
1572                         $this->mNamespace,
1573                         $this->getText(),
1574                         $fragment,
1575                         $this->mInterwiki
1576                 );
1577         }
1578
1579         /**
1580          * Prefix some arbitrary text with the namespace or interwiki prefix
1581          * of this object
1582          *
1583          * @param string $name The text
1584          * @return string The prefixed text
1585          */
1586         private function prefix( $name ) {
1587                 $p = '';
1588                 if ( $this->isExternal() ) {
1589                         $p = $this->mInterwiki . ':';
1590                 }
1591
1592                 if ( $this->mNamespace != 0 ) {
1593                         $nsText = $this->getNsText();
1594
1595                         if ( $nsText === false ) {
1596                                 // See T165149. Awkward, but better than erroneously linking to the main namespace.
1597                                 $nsText = MediaWikiServices::getInstance()->getContentLanguage()->
1598                                         getNsText( NS_SPECIAL ) . ":Badtitle/NS{$this->mNamespace}";
1599                         }
1600
1601                         $p .= $nsText . ':';
1602                 }
1603                 return $p . $name;
1604         }
1605
1606         /**
1607          * Get the prefixed database key form
1608          *
1609          * @return string The prefixed title, with underscores and
1610          *  any interwiki and namespace prefixes
1611          */
1612         public function getPrefixedDBkey() {
1613                 $s = $this->prefix( $this->mDbkeyform );
1614                 $s = strtr( $s, ' ', '_' );
1615                 return $s;
1616         }
1617
1618         /**
1619          * Get the prefixed title with spaces.
1620          * This is the form usually used for display
1621          *
1622          * @return string The prefixed title, with spaces
1623          */
1624         public function getPrefixedText() {
1625                 if ( $this->prefixedText === null ) {
1626                         $s = $this->prefix( $this->mTextform );
1627                         $s = strtr( $s, '_', ' ' );
1628                         $this->prefixedText = $s;
1629                 }
1630                 return $this->prefixedText;
1631         }
1632
1633         /**
1634          * Return a string representation of this title
1635          *
1636          * @return string Representation of this title
1637          */
1638         public function __toString() {
1639                 return $this->getPrefixedText();
1640         }
1641
1642         /**
1643          * Get the prefixed title with spaces, plus any fragment
1644          * (part beginning with '#')
1645          *
1646          * @return string The prefixed title, with spaces and the fragment, including '#'
1647          */
1648         public function getFullText() {
1649                 $text = $this->getPrefixedText();
1650                 if ( $this->hasFragment() ) {
1651                         $text .= '#' . $this->mFragment;
1652                 }
1653                 return $text;
1654         }
1655
1656         /**
1657          * Get the root page name text without a namespace, i.e. the leftmost part before any slashes
1658          *
1659          * @par Example:
1660          * @code
1661          * Title::newFromText('User:Foo/Bar/Baz')->getRootText();
1662          * # returns: 'Foo'
1663          * @endcode
1664          *
1665          * @return string Root name
1666          * @since 1.20
1667          */
1668         public function getRootText() {
1669                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1670                         return $this->getText();
1671                 }
1672
1673                 return strtok( $this->getText(), '/' );
1674         }
1675
1676         /**
1677          * Get the root page name title, i.e. the leftmost part before any slashes
1678          *
1679          * @par Example:
1680          * @code
1681          * Title::newFromText('User:Foo/Bar/Baz')->getRootTitle();
1682          * # returns: Title{User:Foo}
1683          * @endcode
1684          *
1685          * @return Title Root title
1686          * @since 1.20
1687          */
1688         public function getRootTitle() {
1689                 return self::makeTitle( $this->mNamespace, $this->getRootText() );
1690         }
1691
1692         /**
1693          * Get the base page name without a namespace, i.e. the part before the subpage name
1694          *
1695          * @par Example:
1696          * @code
1697          * Title::newFromText('User:Foo/Bar/Baz')->getBaseText();
1698          * # returns: 'Foo/Bar'
1699          * @endcode
1700          *
1701          * @return string Base name
1702          */
1703         public function getBaseText() {
1704                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1705                         return $this->getText();
1706                 }
1707
1708                 $parts = explode( '/', $this->getText() );
1709                 # Don't discard the real title if there's no subpage involved
1710                 if ( count( $parts ) > 1 ) {
1711                         unset( $parts[count( $parts ) - 1] );
1712                 }
1713                 return implode( '/', $parts );
1714         }
1715
1716         /**
1717          * Get the base page name title, i.e. the part before the subpage name
1718          *
1719          * @par Example:
1720          * @code
1721          * Title::newFromText('User:Foo/Bar/Baz')->getBaseTitle();
1722          * # returns: Title{User:Foo/Bar}
1723          * @endcode
1724          *
1725          * @return Title Base title
1726          * @since 1.20
1727          */
1728         public function getBaseTitle() {
1729                 return self::makeTitle( $this->mNamespace, $this->getBaseText() );
1730         }
1731
1732         /**
1733          * Get the lowest-level subpage name, i.e. the rightmost part after any slashes
1734          *
1735          * @par Example:
1736          * @code
1737          * Title::newFromText('User:Foo/Bar/Baz')->getSubpageText();
1738          * # returns: "Baz"
1739          * @endcode
1740          *
1741          * @return string Subpage name
1742          */
1743         public function getSubpageText() {
1744                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1745                         return $this->mTextform;
1746                 }
1747                 $parts = explode( '/', $this->mTextform );
1748                 return $parts[count( $parts ) - 1];
1749         }
1750
1751         /**
1752          * Get the title for a subpage of the current page
1753          *
1754          * @par Example:
1755          * @code
1756          * Title::newFromText('User:Foo/Bar/Baz')->getSubpage("Asdf");
1757          * # returns: Title{User:Foo/Bar/Baz/Asdf}
1758          * @endcode
1759          *
1760          * @param string $text The subpage name to add to the title
1761          * @return Title|null Subpage title, or null on an error
1762          * @since 1.20
1763          */
1764         public function getSubpage( $text ) {
1765                 return self::makeTitleSafe( $this->mNamespace, $this->getText() . '/' . $text );
1766         }
1767
1768         /**
1769          * Get a URL-encoded form of the subpage text
1770          *
1771          * @return string URL-encoded subpage name
1772          */
1773         public function getSubpageUrlForm() {
1774                 $text = $this->getSubpageText();
1775                 $text = wfUrlencode( strtr( $text, ' ', '_' ) );
1776                 return $text;
1777         }
1778
1779         /**
1780          * Get a URL-encoded title (not an actual URL) including interwiki
1781          *
1782          * @return string The URL-encoded form
1783          */
1784         public function getPrefixedURL() {
1785                 $s = $this->prefix( $this->mDbkeyform );
1786                 $s = wfUrlencode( strtr( $s, ' ', '_' ) );
1787                 return $s;
1788         }
1789
1790         /**
1791          * Helper to fix up the get{Canonical,Full,Link,Local,Internal}URL args
1792          * get{Canonical,Full,Link,Local,Internal}URL methods accepted an optional
1793          * second argument named variant. This was deprecated in favor
1794          * of passing an array of option with a "variant" key
1795          * Once $query2 is removed for good, this helper can be dropped
1796          * and the wfArrayToCgi moved to getLocalURL();
1797          *
1798          * @since 1.19 (r105919)
1799          * @param array|string $query
1800          * @param string|string[]|bool $query2
1801          * @return string
1802          */
1803         private static function fixUrlQueryArgs( $query, $query2 = false ) {
1804                 if ( $query2 !== false ) {
1805                         wfDeprecated( "Title::get{Canonical,Full,Link,Local,Internal}URL " .
1806                                 "method called with a second parameter is deprecated. Add your " .
1807                                 "parameter to an array passed as the first parameter.", "1.19" );
1808                 }
1809                 if ( is_array( $query ) ) {
1810                         $query = wfArrayToCgi( $query );
1811                 }
1812                 if ( $query2 ) {
1813                         if ( is_string( $query2 ) ) {
1814                                 // $query2 is a string, we will consider this to be
1815                                 // a deprecated $variant argument and add it to the query
1816                                 $query2 = wfArrayToCgi( [ 'variant' => $query2 ] );
1817                         } else {
1818                                 $query2 = wfArrayToCgi( $query2 );
1819                         }
1820                         // If we have $query content add a & to it first
1821                         if ( $query ) {
1822                                 $query .= '&';
1823                         }
1824                         // Now append the queries together
1825                         $query .= $query2;
1826                 }
1827                 return $query;
1828         }
1829
1830         /**
1831          * Get a real URL referring to this title, with interwiki link and
1832          * fragment
1833          *
1834          * @see self::getLocalURL for the arguments.
1835          * @see wfExpandUrl
1836          * @param string|string[] $query
1837          * @param string|string[]|bool $query2
1838          * @param string|int|null $proto Protocol type to use in URL
1839          * @return string The URL
1840          */
1841         public function getFullURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1842                 $query = self::fixUrlQueryArgs( $query, $query2 );
1843
1844                 # Hand off all the decisions on urls to getLocalURL
1845                 $url = $this->getLocalURL( $query );
1846
1847                 # Expand the url to make it a full url. Note that getLocalURL has the
1848                 # potential to output full urls for a variety of reasons, so we use
1849                 # wfExpandUrl instead of simply prepending $wgServer
1850                 $url = wfExpandUrl( $url, $proto );
1851
1852                 # Finally, add the fragment.
1853                 $url .= $this->getFragmentForURL();
1854                 // Avoid PHP 7.1 warning from passing $this by reference
1855                 $titleRef = $this;
1856                 Hooks::run( 'GetFullURL', [ &$titleRef, &$url, $query ] );
1857                 return $url;
1858         }
1859
1860         /**
1861          * Get a url appropriate for making redirects based on an untrusted url arg
1862          *
1863          * This is basically the same as getFullUrl(), but in the case of external
1864          * interwikis, we send the user to a landing page, to prevent possible
1865          * phishing attacks and the like.
1866          *
1867          * @note Uses current protocol by default, since technically relative urls
1868          *   aren't allowed in redirects per HTTP spec, so this is not suitable for
1869          *   places where the url gets cached, as might pollute between
1870          *   https and non-https users.
1871          * @see self::getLocalURL for the arguments.
1872          * @param array|string $query
1873          * @param string $proto Protocol type to use in URL
1874          * @return string A url suitable to use in an HTTP location header.
1875          */
1876         public function getFullUrlForRedirect( $query = '', $proto = PROTO_CURRENT ) {
1877                 $target = $this;
1878                 if ( $this->isExternal() ) {
1879                         $target = SpecialPage::getTitleFor(
1880                                 'GoToInterwiki',
1881                                 $this->getPrefixedDBkey()
1882                         );
1883                 }
1884                 return $target->getFullURL( $query, false, $proto );
1885         }
1886
1887         /**
1888          * Get a URL with no fragment or server name (relative URL) from a Title object.
1889          * If this page is generated with action=render, however,
1890          * $wgServer is prepended to make an absolute URL.
1891          *
1892          * @see self::getFullURL to always get an absolute URL.
1893          * @see self::getLinkURL to always get a URL that's the simplest URL that will be
1894          *  valid to link, locally, to the current Title.
1895          * @see self::newFromText to produce a Title object.
1896          *
1897          * @param string|string[] $query An optional query string,
1898          *   not used for interwiki links. Can be specified as an associative array as well,
1899          *   e.g., array( 'action' => 'edit' ) (keys and values will be URL-escaped).
1900          *   Some query patterns will trigger various shorturl path replacements.
1901          * @param string|string[]|bool $query2 An optional secondary query array. This one MUST
1902          *   be an array. If a string is passed it will be interpreted as a deprecated
1903          *   variant argument and urlencoded into a variant= argument.
1904          *   This second query argument will be added to the $query
1905          *   The second parameter is deprecated since 1.19. Pass it as a key,value
1906          *   pair in the first parameter array instead.
1907          *
1908          * @return string String of the URL.
1909          */
1910         public function getLocalURL( $query = '', $query2 = false ) {
1911                 global $wgArticlePath, $wgScript, $wgServer, $wgRequest;
1912
1913                 $query = self::fixUrlQueryArgs( $query, $query2 );
1914
1915                 $interwiki = self::getInterwikiLookup()->fetch( $this->mInterwiki );
1916                 if ( $interwiki ) {
1917                         $namespace = $this->getNsText();
1918                         if ( $namespace != '' ) {
1919                                 # Can this actually happen? Interwikis shouldn't be parsed.
1920                                 # Yes! It can in interwiki transclusion. But... it probably shouldn't.
1921                                 $namespace .= ':';
1922                         }
1923                         $url = $interwiki->getURL( $namespace . $this->mDbkeyform );
1924                         $url = wfAppendQuery( $url, $query );
1925                 } else {
1926                         $dbkey = wfUrlencode( $this->getPrefixedDBkey() );
1927                         if ( $query == '' ) {
1928                                 $url = str_replace( '$1', $dbkey, $wgArticlePath );
1929                                 // Avoid PHP 7.1 warning from passing $this by reference
1930                                 $titleRef = $this;
1931                                 Hooks::run( 'GetLocalURL::Article', [ &$titleRef, &$url ] );
1932                         } else {
1933                                 global $wgVariantArticlePath, $wgActionPaths;
1934                                 $url = false;
1935                                 $matches = [];
1936
1937                                 if ( !empty( $wgActionPaths )
1938                                         && preg_match( '/^(.*&|)action=([^&]*)(&(.*)|)$/', $query, $matches )
1939                                 ) {
1940                                         $action = urldecode( $matches[2] );
1941                                         if ( isset( $wgActionPaths[$action] ) ) {
1942                                                 $query = $matches[1];
1943                                                 if ( isset( $matches[4] ) ) {
1944                                                         $query .= $matches[4];
1945                                                 }
1946                                                 $url = str_replace( '$1', $dbkey, $wgActionPaths[$action] );
1947                                                 if ( $query != '' ) {
1948                                                         $url = wfAppendQuery( $url, $query );
1949                                                 }
1950                                         }
1951                                 }
1952
1953                                 if ( $url === false
1954                                         && $wgVariantArticlePath
1955                                         && preg_match( '/^variant=([^&]*)$/', $query, $matches )
1956                                         && $this->getPageLanguage()->equals(
1957                                                 MediaWikiServices::getInstance()->getContentLanguage() )
1958                                         && $this->getPageLanguage()->hasVariants()
1959                                 ) {
1960                                         $variant = urldecode( $matches[1] );
1961                                         if ( $this->getPageLanguage()->hasVariant( $variant ) ) {
1962                                                 // Only do the variant replacement if the given variant is a valid
1963                                                 // variant for the page's language.
1964                                                 $url = str_replace( '$2', urlencode( $variant ), $wgVariantArticlePath );
1965                                                 $url = str_replace( '$1', $dbkey, $url );
1966                                         }
1967                                 }
1968
1969                                 if ( $url === false ) {
1970                                         if ( $query == '-' ) {
1971                                                 $query = '';
1972                                         }
1973                                         $url = "{$wgScript}?title={$dbkey}&{$query}";
1974                                 }
1975                         }
1976                         // Avoid PHP 7.1 warning from passing $this by reference
1977                         $titleRef = $this;
1978                         Hooks::run( 'GetLocalURL::Internal', [ &$titleRef, &$url, $query ] );
1979
1980                         // @todo FIXME: This causes breakage in various places when we
1981                         // actually expected a local URL and end up with dupe prefixes.
1982                         if ( $wgRequest->getVal( 'action' ) == 'render' ) {
1983                                 $url = $wgServer . $url;
1984                         }
1985                 }
1986                 // Avoid PHP 7.1 warning from passing $this by reference
1987                 $titleRef = $this;
1988                 Hooks::run( 'GetLocalURL', [ &$titleRef, &$url, $query ] );
1989                 return $url;
1990         }
1991
1992         /**
1993          * Get a URL that's the simplest URL that will be valid to link, locally,
1994          * to the current Title.  It includes the fragment, but does not include
1995          * the server unless action=render is used (or the link is external).  If
1996          * there's a fragment but the prefixed text is empty, we just return a link
1997          * to the fragment.
1998          *
1999          * The result obviously should not be URL-escaped, but does need to be
2000          * HTML-escaped if it's being output in HTML.
2001          *
2002          * @param string|string[] $query
2003          * @param bool $query2
2004          * @param string|int|bool $proto A PROTO_* constant on how the URL should be expanded,
2005          *                               or false (default) for no expansion
2006          * @see self::getLocalURL for the arguments.
2007          * @return string The URL
2008          */
2009         public function getLinkURL( $query = '', $query2 = false, $proto = false ) {
2010                 if ( $this->isExternal() || $proto !== false ) {
2011                         $ret = $this->getFullURL( $query, $query2, $proto );
2012                 } elseif ( $this->getPrefixedText() === '' && $this->hasFragment() ) {
2013                         $ret = $this->getFragmentForURL();
2014                 } else {
2015                         $ret = $this->getLocalURL( $query, $query2 ) . $this->getFragmentForURL();
2016                 }
2017                 return $ret;
2018         }
2019
2020         /**
2021          * Get the URL form for an internal link.
2022          * - Used in various CDN-related code, in case we have a different
2023          * internal hostname for the server from the exposed one.
2024          *
2025          * This uses $wgInternalServer to qualify the path, or $wgServer
2026          * if $wgInternalServer is not set. If the server variable used is
2027          * protocol-relative, the URL will be expanded to http://
2028          *
2029          * @see self::getLocalURL for the arguments.
2030          * @param string $query
2031          * @param string|bool $query2
2032          * @return string The URL
2033          */
2034         public function getInternalURL( $query = '', $query2 = false ) {
2035                 global $wgInternalServer, $wgServer;
2036                 $query = self::fixUrlQueryArgs( $query, $query2 );
2037                 $server = $wgInternalServer !== false ? $wgInternalServer : $wgServer;
2038                 $url = wfExpandUrl( $server . $this->getLocalURL( $query ), PROTO_HTTP );
2039                 // Avoid PHP 7.1 warning from passing $this by reference
2040                 $titleRef = $this;
2041                 Hooks::run( 'GetInternalURL', [ &$titleRef, &$url, $query ] );
2042                 return $url;
2043         }
2044
2045         /**
2046          * Get the URL for a canonical link, for use in things like IRC and
2047          * e-mail notifications. Uses $wgCanonicalServer and the
2048          * GetCanonicalURL hook.
2049          *
2050          * NOTE: Unlike getInternalURL(), the canonical URL includes the fragment
2051          *
2052          * @see self::getLocalURL for the arguments.
2053          * @param string $query
2054          * @param string|bool $query2
2055          * @return string The URL
2056          * @since 1.18
2057          */
2058         public function getCanonicalURL( $query = '', $query2 = false ) {
2059                 $query = self::fixUrlQueryArgs( $query, $query2 );
2060                 $url = wfExpandUrl( $this->getLocalURL( $query ) . $this->getFragmentForURL(), PROTO_CANONICAL );
2061                 // Avoid PHP 7.1 warning from passing $this by reference
2062                 $titleRef = $this;
2063                 Hooks::run( 'GetCanonicalURL', [ &$titleRef, &$url, $query ] );
2064                 return $url;
2065         }
2066
2067         /**
2068          * Get the edit URL for this Title
2069          *
2070          * @return string The URL, or a null string if this is an interwiki link
2071          */
2072         public function getEditURL() {
2073                 if ( $this->isExternal() ) {
2074                         return '';
2075                 }
2076                 $s = $this->getLocalURL( 'action=edit' );
2077
2078                 return $s;
2079         }
2080
2081         /**
2082          * Can $user perform $action on this page?
2083          * This skips potentially expensive cascading permission checks
2084          * as well as avoids expensive error formatting
2085          *
2086          * Suitable for use for nonessential UI controls in common cases, but
2087          * _not_ for functional access control.
2088          *
2089          * May provide false positives, but should never provide a false negative.
2090          *
2091          * @param string $action Action that permission needs to be checked for
2092          * @param User|null $user User to check (since 1.19); $wgUser will be used if not provided.
2093          * @return bool
2094          */
2095         public function quickUserCan( $action, $user = null ) {
2096                 return $this->userCan( $action, $user, false );
2097         }
2098
2099         /**
2100          * Can $user perform $action on this page?
2101          *
2102          * @param string $action Action that permission needs to be checked for
2103          * @param User|null $user User to check (since 1.19); $wgUser will be used if not
2104          *   provided.
2105          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2106          * @return bool
2107          */
2108         public function userCan( $action, $user = null, $rigor = 'secure' ) {
2109                 if ( !$user instanceof User ) {
2110                         global $wgUser;
2111                         $user = $wgUser;
2112                 }
2113
2114                 return !count( $this->getUserPermissionsErrorsInternal( $action, $user, $rigor, true ) );
2115         }
2116
2117         /**
2118          * Can $user perform $action on this page?
2119          *
2120          * @todo FIXME: This *does not* check throttles (User::pingLimiter()).
2121          *
2122          * @param string $action Action that permission needs to be checked for
2123          * @param User $user User to check
2124          * @param string $rigor One of (quick,full,secure)
2125          *   - quick  : does cheap permission checks from replica DBs (usable for GUI creation)
2126          *   - full   : does cheap and expensive checks possibly from a replica DB
2127          *   - secure : does cheap and expensive checks, using the master as needed
2128          * @param array $ignoreErrors Array of Strings Set this to a list of message keys
2129          *   whose corresponding errors may be ignored.
2130          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
2131          */
2132         public function getUserPermissionsErrors(
2133                 $action, $user, $rigor = 'secure', $ignoreErrors = []
2134         ) {
2135                 $errors = $this->getUserPermissionsErrorsInternal( $action, $user, $rigor );
2136
2137                 // Remove the errors being ignored.
2138                 foreach ( $errors as $index => $error ) {
2139                         $errKey = is_array( $error ) ? $error[0] : $error;
2140
2141                         if ( in_array( $errKey, $ignoreErrors ) ) {
2142                                 unset( $errors[$index] );
2143                         }
2144                         if ( $errKey instanceof MessageSpecifier && in_array( $errKey->getKey(), $ignoreErrors ) ) {
2145                                 unset( $errors[$index] );
2146                         }
2147                 }
2148
2149                 return $errors;
2150         }
2151
2152         /**
2153          * Permissions checks that fail most often, and which are easiest to test.
2154          *
2155          * @param string $action The action to check
2156          * @param User $user User to check
2157          * @param array $errors List of current errors
2158          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2159          * @param bool $short Short circuit on first error
2160          *
2161          * @return array List of errors
2162          */
2163         private function checkQuickPermissions( $action, $user, $errors, $rigor, $short ) {
2164                 if ( !Hooks::run( 'TitleQuickPermissions',
2165                         [ $this, $user, $action, &$errors, ( $rigor !== 'quick' ), $short ] )
2166                 ) {
2167                         return $errors;
2168                 }
2169
2170                 if ( $action == 'create' ) {
2171                         if (
2172                                 ( $this->isTalkPage() && !$user->isAllowed( 'createtalk' ) ) ||
2173                                 ( !$this->isTalkPage() && !$user->isAllowed( 'createpage' ) )
2174                         ) {
2175                                 $errors[] = $user->isAnon() ? [ 'nocreatetext' ] : [ 'nocreate-loggedin' ];
2176                         }
2177                 } elseif ( $action == 'move' ) {
2178                         if ( !$user->isAllowed( 'move-rootuserpages' )
2179                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
2180                                 // Show user page-specific message only if the user can move other pages
2181                                 $errors[] = [ 'cant-move-user-page' ];
2182                         }
2183
2184                         // Check if user is allowed to move files if it's a file
2185                         if ( $this->mNamespace == NS_FILE && !$user->isAllowed( 'movefile' ) ) {
2186                                 $errors[] = [ 'movenotallowedfile' ];
2187                         }
2188
2189                         // Check if user is allowed to move category pages if it's a category page
2190                         if ( $this->mNamespace == NS_CATEGORY && !$user->isAllowed( 'move-categorypages' ) ) {
2191                                 $errors[] = [ 'cant-move-category-page' ];
2192                         }
2193
2194                         if ( !$user->isAllowed( 'move' ) ) {
2195                                 // User can't move anything
2196                                 $userCanMove = User::groupHasPermission( 'user', 'move' );
2197                                 $autoconfirmedCanMove = User::groupHasPermission( 'autoconfirmed', 'move' );
2198                                 if ( $user->isAnon() && ( $userCanMove || $autoconfirmedCanMove ) ) {
2199                                         // custom message if logged-in users without any special rights can move
2200                                         $errors[] = [ 'movenologintext' ];
2201                                 } else {
2202                                         $errors[] = [ 'movenotallowed' ];
2203                                 }
2204                         }
2205                 } elseif ( $action == 'move-target' ) {
2206                         if ( !$user->isAllowed( 'move' ) ) {
2207                                 // User can't move anything
2208                                 $errors[] = [ 'movenotallowed' ];
2209                         } elseif ( !$user->isAllowed( 'move-rootuserpages' )
2210                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
2211                                 // Show user page-specific message only if the user can move other pages
2212                                 $errors[] = [ 'cant-move-to-user-page' ];
2213                         } elseif ( !$user->isAllowed( 'move-categorypages' )
2214                                         && $this->mNamespace == NS_CATEGORY ) {
2215                                 // Show category page-specific message only if the user can move other pages
2216                                 $errors[] = [ 'cant-move-to-category-page' ];
2217                         }
2218                 } elseif ( !$user->isAllowed( $action ) ) {
2219                         $errors[] = $this->missingPermissionError( $action, $short );
2220                 }
2221
2222                 return $errors;
2223         }
2224
2225         /**
2226          * Add the resulting error code to the errors array
2227          *
2228          * @param array $errors List of current errors
2229          * @param array $result Result of errors
2230          *
2231          * @return array List of errors
2232          */
2233         private function resultToError( $errors, $result ) {
2234                 if ( is_array( $result ) && count( $result ) && !is_array( $result[0] ) ) {
2235                         // A single array representing an error
2236                         $errors[] = $result;
2237                 } elseif ( is_array( $result ) && is_array( $result[0] ) ) {
2238                         // A nested array representing multiple errors
2239                         $errors = array_merge( $errors, $result );
2240                 } elseif ( $result !== '' && is_string( $result ) ) {
2241                         // A string representing a message-id
2242                         $errors[] = [ $result ];
2243                 } elseif ( $result instanceof MessageSpecifier ) {
2244                         // A message specifier representing an error
2245                         $errors[] = [ $result ];
2246                 } elseif ( $result === false ) {
2247                         // a generic "We don't want them to do that"
2248                         $errors[] = [ 'badaccess-group0' ];
2249                 }
2250                 return $errors;
2251         }
2252
2253         /**
2254          * Check various permission hooks
2255          *
2256          * @param string $action The action to check
2257          * @param User $user User to check
2258          * @param array $errors List of current errors
2259          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2260          * @param bool $short Short circuit on first error
2261          *
2262          * @return array List of errors
2263          */
2264         private function checkPermissionHooks( $action, $user, $errors, $rigor, $short ) {
2265                 // Use getUserPermissionsErrors instead
2266                 $result = '';
2267                 // Avoid PHP 7.1 warning from passing $this by reference
2268                 $titleRef = $this;
2269                 if ( !Hooks::run( 'userCan', [ &$titleRef, &$user, $action, &$result ] ) ) {
2270                         return $result ? [] : [ [ 'badaccess-group0' ] ];
2271                 }
2272                 // Check getUserPermissionsErrors hook
2273                 // Avoid PHP 7.1 warning from passing $this by reference
2274                 $titleRef = $this;
2275                 if ( !Hooks::run( 'getUserPermissionsErrors', [ &$titleRef, &$user, $action, &$result ] ) ) {
2276                         $errors = $this->resultToError( $errors, $result );
2277                 }
2278                 // Check getUserPermissionsErrorsExpensive hook
2279                 if (
2280                         $rigor !== 'quick'
2281                         && !( $short && count( $errors ) > 0 )
2282                         && !Hooks::run( 'getUserPermissionsErrorsExpensive', [ &$titleRef, &$user, $action, &$result ] )
2283                 ) {
2284                         $errors = $this->resultToError( $errors, $result );
2285                 }
2286
2287                 return $errors;
2288         }
2289
2290         /**
2291          * Check permissions on special pages & namespaces
2292          *
2293          * @param string $action The action to check
2294          * @param User $user User to check
2295          * @param array $errors List of current errors
2296          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2297          * @param bool $short Short circuit on first error
2298          *
2299          * @return array List of errors
2300          */
2301         private function checkSpecialsAndNSPermissions( $action, $user, $errors, $rigor, $short ) {
2302                 # Only 'createaccount' can be performed on special pages,
2303                 # which don't actually exist in the DB.
2304                 if ( $this->isSpecialPage() && $action !== 'createaccount' ) {
2305                         $errors[] = [ 'ns-specialprotected' ];
2306                 }
2307
2308                 # Check $wgNamespaceProtection for restricted namespaces
2309                 if ( $this->isNamespaceProtected( $user ) ) {
2310                         $ns = $this->mNamespace == NS_MAIN ?
2311                                 wfMessage( 'nstab-main' )->text() : $this->getNsText();
2312                         $errors[] = $this->mNamespace == NS_MEDIAWIKI ?
2313                                 [ 'protectedinterface', $action ] : [ 'namespaceprotected', $ns, $action ];
2314                 }
2315
2316                 return $errors;
2317         }
2318
2319         /**
2320          * Check sitewide CSS/JSON/JS permissions
2321          *
2322          * @param string $action The action to check
2323          * @param User $user User to check
2324          * @param array $errors List of current errors
2325          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2326          * @param bool $short Short circuit on first error
2327          *
2328          * @return array List of errors
2329          */
2330         private function checkSiteConfigPermissions( $action, $user, $errors, $rigor, $short ) {
2331                 if ( $action != 'patrol' ) {
2332                         $error = null;
2333                         // Sitewide CSS/JSON/JS changes, like all NS_MEDIAWIKI changes, also require the
2334                         // editinterface right. That's implemented as a restriction so no check needed here.
2335                         if ( $this->isSiteCssConfigPage() && !$user->isAllowed( 'editsitecss' ) ) {
2336                                 $error = [ 'sitecssprotected', $action ];
2337                         } elseif ( $this->isSiteJsonConfigPage() && !$user->isAllowed( 'editsitejson' ) ) {
2338                                 $error = [ 'sitejsonprotected', $action ];
2339                         } elseif ( $this->isSiteJsConfigPage() && !$user->isAllowed( 'editsitejs' ) ) {
2340                                 $error = [ 'sitejsprotected', $action ];
2341                         } elseif ( $this->isRawHtmlMessage() ) {
2342                                 // Raw HTML can be used to deploy CSS or JS so require rights for both.
2343                                 if ( !$user->isAllowed( 'editsitejs' ) ) {
2344                                         $error = [ 'sitejsprotected', $action ];
2345                                 } elseif ( !$user->isAllowed( 'editsitecss' ) ) {
2346                                         $error = [ 'sitecssprotected', $action ];
2347                                 }
2348                         }
2349
2350                         if ( $error ) {
2351                                 if ( $user->isAllowed( 'editinterface' ) ) {
2352                                         // Most users / site admins will probably find out about the new, more restrictive
2353                                         // permissions by failing to edit something. Give them more info.
2354                                         // TODO remove this a few release cycles after 1.32
2355                                         $error = [ 'interfaceadmin-info', wfMessage( $error[0], $error[1] ) ];
2356                                 }
2357                                 $errors[] = $error;
2358                         }
2359                 }
2360
2361                 return $errors;
2362         }
2363
2364         /**
2365          * Check CSS/JSON/JS sub-page permissions
2366          *
2367          * @param string $action The action to check
2368          * @param User $user User to check
2369          * @param array $errors List of current errors
2370          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2371          * @param bool $short Short circuit on first error
2372          *
2373          * @return array List of errors
2374          */
2375         private function checkUserConfigPermissions( $action, $user, $errors, $rigor, $short ) {
2376                 # Protect css/json/js subpages of user pages
2377                 # XXX: this might be better using restrictions
2378
2379                 if ( $action === 'patrol' ) {
2380                         return $errors;
2381                 }
2382
2383                 if ( preg_match( '/^' . preg_quote( $user->getName(), '/' ) . '\//', $this->mTextform ) ) {
2384                         // Users need editmyuser* to edit their own CSS/JSON/JS subpages.
2385                         if (
2386                                 $this->isUserCssConfigPage()
2387                                 && !$user->isAllowedAny( 'editmyusercss', 'editusercss' )
2388                         ) {
2389                                 $errors[] = [ 'mycustomcssprotected', $action ];
2390                         } elseif (
2391                                 $this->isUserJsonConfigPage()
2392                                 && !$user->isAllowedAny( 'editmyuserjson', 'edituserjson' )
2393                         ) {
2394                                 $errors[] = [ 'mycustomjsonprotected', $action ];
2395                         } elseif (
2396                                 $this->isUserJsConfigPage()
2397                                 && !$user->isAllowedAny( 'editmyuserjs', 'edituserjs' )
2398                         ) {
2399                                 $errors[] = [ 'mycustomjsprotected', $action ];
2400                         }
2401                 } else {
2402                         // Users need editmyuser* to edit their own CSS/JSON/JS subpages, except for
2403                         // deletion/suppression which cannot be used for attacks and we want to avoid the
2404                         // situation where an unprivileged user can post abusive content on their subpages
2405                         // and only very highly privileged users could remove it.
2406                         if ( !in_array( $action, [ 'delete', 'deleterevision', 'suppressrevision' ], true ) ) {
2407                                 if (
2408                                         $this->isUserCssConfigPage()
2409                                         && !$user->isAllowed( 'editusercss' )
2410                                 ) {
2411                                         $errors[] = [ 'customcssprotected', $action ];
2412                                 } elseif (
2413                                         $this->isUserJsonConfigPage()
2414                                         && !$user->isAllowed( 'edituserjson' )
2415                                 ) {
2416                                         $errors[] = [ 'customjsonprotected', $action ];
2417                                 } elseif (
2418                                         $this->isUserJsConfigPage()
2419                                         && !$user->isAllowed( 'edituserjs' )
2420                                 ) {
2421                                         $errors[] = [ 'customjsprotected', $action ];
2422                                 }
2423                         }
2424                 }
2425
2426                 return $errors;
2427         }
2428
2429         /**
2430          * Check against page_restrictions table requirements on this
2431          * page. The user must possess all required rights for this
2432          * action.
2433          *
2434          * @param string $action The action to check
2435          * @param User $user User to check
2436          * @param array $errors List of current errors
2437          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2438          * @param bool $short Short circuit on first error
2439          *
2440          * @return array List of errors
2441          */
2442         private function checkPageRestrictions( $action, $user, $errors, $rigor, $short ) {
2443                 foreach ( $this->getRestrictions( $action ) as $right ) {
2444                         // Backwards compatibility, rewrite sysop -> editprotected
2445                         if ( $right == 'sysop' ) {
2446                                 $right = 'editprotected';
2447                         }
2448                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2449                         if ( $right == 'autoconfirmed' ) {
2450                                 $right = 'editsemiprotected';
2451                         }
2452                         if ( $right == '' ) {
2453                                 continue;
2454                         }
2455                         if ( !$user->isAllowed( $right ) ) {
2456                                 $errors[] = [ 'protectedpagetext', $right, $action ];
2457                         } elseif ( $this->mCascadeRestriction && !$user->isAllowed( 'protect' ) ) {
2458                                 $errors[] = [ 'protectedpagetext', 'protect', $action ];
2459                         }
2460                 }
2461
2462                 return $errors;
2463         }
2464
2465         /**
2466          * Check restrictions on cascading pages.
2467          *
2468          * @param string $action The action to check
2469          * @param User $user User to check
2470          * @param array $errors List of current errors
2471          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2472          * @param bool $short Short circuit on first error
2473          *
2474          * @return array List of errors
2475          */
2476         private function checkCascadingSourcesRestrictions( $action, $user, $errors, $rigor, $short ) {
2477                 if ( $rigor !== 'quick' && !$this->isUserConfigPage() ) {
2478                         # We /could/ use the protection level on the source page, but it's
2479                         # fairly ugly as we have to establish a precedence hierarchy for pages
2480                         # included by multiple cascade-protected pages. So just restrict
2481                         # it to people with 'protect' permission, as they could remove the
2482                         # protection anyway.
2483                         list( $cascadingSources, $restrictions ) = $this->getCascadeProtectionSources();
2484                         # Cascading protection depends on more than this page...
2485                         # Several cascading protected pages may include this page...
2486                         # Check each cascading level
2487                         # This is only for protection restrictions, not for all actions
2488                         if ( isset( $restrictions[$action] ) ) {
2489                                 foreach ( $restrictions[$action] as $right ) {
2490                                         // Backwards compatibility, rewrite sysop -> editprotected
2491                                         if ( $right == 'sysop' ) {
2492                                                 $right = 'editprotected';
2493                                         }
2494                                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2495                                         if ( $right == 'autoconfirmed' ) {
2496                                                 $right = 'editsemiprotected';
2497                                         }
2498                                         if ( $right != '' && !$user->isAllowedAll( 'protect', $right ) ) {
2499                                                 $pages = '';
2500                                                 foreach ( $cascadingSources as $page ) {
2501                                                         $pages .= '* [[:' . $page->getPrefixedText() . "]]\n";
2502                                                 }
2503                                                 $errors[] = [ 'cascadeprotected', count( $cascadingSources ), $pages, $action ];
2504                                         }
2505                                 }
2506                         }
2507                 }
2508
2509                 return $errors;
2510         }
2511
2512         /**
2513          * Check action permissions not already checked in checkQuickPermissions
2514          *
2515          * @param string $action The action to check
2516          * @param User $user User to check
2517          * @param array $errors List of current errors
2518          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2519          * @param bool $short Short circuit on first error
2520          *
2521          * @return array List of errors
2522          */
2523         private function checkActionPermissions( $action, $user, $errors, $rigor, $short ) {
2524                 global $wgDeleteRevisionsLimit, $wgLang;
2525
2526                 if ( $action == 'protect' ) {
2527                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit', $user, $rigor, true ) ) ) {
2528                                 // If they can't edit, they shouldn't protect.
2529                                 $errors[] = [ 'protect-cantedit' ];
2530                         }
2531                 } elseif ( $action == 'create' ) {
2532                         $title_protection = $this->getTitleProtection();
2533                         if ( $title_protection ) {
2534                                 if ( $title_protection['permission'] == ''
2535                                         || !$user->isAllowed( $title_protection['permission'] )
2536                                 ) {
2537                                         $errors[] = [
2538                                                 'titleprotected',
2539                                                 User::whoIs( $title_protection['user'] ),
2540                                                 $title_protection['reason']
2541                                         ];
2542                                 }
2543                         }
2544                 } elseif ( $action == 'move' ) {
2545                         // Check for immobile pages
2546                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2547                                 // Specific message for this case
2548                                 $errors[] = [ 'immobile-source-namespace', $this->getNsText() ];
2549                         } elseif ( !$this->isMovable() ) {
2550                                 // Less specific message for rarer cases
2551                                 $errors[] = [ 'immobile-source-page' ];
2552                         }
2553                 } elseif ( $action == 'move-target' ) {
2554                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2555                                 $errors[] = [ 'immobile-target-namespace', $this->getNsText() ];
2556                         } elseif ( !$this->isMovable() ) {
2557                                 $errors[] = [ 'immobile-target-page' ];
2558                         }
2559                 } elseif ( $action == 'delete' ) {
2560                         $tempErrors = $this->checkPageRestrictions( 'edit', $user, [], $rigor, true );
2561                         if ( !$tempErrors ) {
2562                                 $tempErrors = $this->checkCascadingSourcesRestrictions( 'edit',
2563                                         $user, $tempErrors, $rigor, true );
2564                         }
2565                         if ( $tempErrors ) {
2566                                 // If protection keeps them from editing, they shouldn't be able to delete.
2567                                 $errors[] = [ 'deleteprotected' ];
2568                         }
2569                         if ( $rigor !== 'quick' && $wgDeleteRevisionsLimit
2570                                 && !$this->userCan( 'bigdelete', $user ) && $this->isBigDeletion()
2571                         ) {
2572                                 $errors[] = [ 'delete-toobig', $wgLang->formatNum( $wgDeleteRevisionsLimit ) ];
2573                         }
2574                 } elseif ( $action === 'undelete' ) {
2575                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit', $user, $rigor, true ) ) ) {
2576                                 // Undeleting implies editing
2577                                 $errors[] = [ 'undelete-cantedit' ];
2578                         }
2579                         if ( !$this->exists()
2580                                 && count( $this->getUserPermissionsErrorsInternal( 'create', $user, $rigor, true ) )
2581                         ) {
2582                                 // Undeleting where nothing currently exists implies creating
2583                                 $errors[] = [ 'undelete-cantcreate' ];
2584                         }
2585                 }
2586                 return $errors;
2587         }
2588
2589         /**
2590          * Check that the user isn't blocked from editing.
2591          *
2592          * @param string $action The action to check
2593          * @param User $user User to check
2594          * @param array $errors List of current errors
2595          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2596          * @param bool $short Short circuit on first error
2597          *
2598          * @return array List of errors
2599          */
2600         private function checkUserBlock( $action, $user, $errors, $rigor, $short ) {
2601                 global $wgEmailConfirmToEdit, $wgBlockDisablesLogin;
2602                 // Account creation blocks handled at userlogin.
2603                 // Unblocking handled in SpecialUnblock
2604                 if ( $rigor === 'quick' || in_array( $action, [ 'createaccount', 'unblock' ] ) ) {
2605                         return $errors;
2606                 }
2607
2608                 // Optimize for a very common case
2609                 if ( $action === 'read' && !$wgBlockDisablesLogin ) {
2610                         return $errors;
2611                 }
2612
2613                 if ( $wgEmailConfirmToEdit
2614                         && !$user->isEmailConfirmed()
2615                         && $action === 'edit'
2616                 ) {
2617                         $errors[] = [ 'confirmedittext' ];
2618                 }
2619
2620                 $useReplica = ( $rigor !== 'secure' );
2621                 $block = $user->getBlock( $useReplica );
2622
2623                 // The block may explicitly allow an action (like "read" or "upload").
2624                 if ( $block && $block->appliesToRight( $action ) === false ) {
2625                         return $errors;
2626                 }
2627
2628                 // Determine if the user is blocked from this action on this page.
2629                 // What gets passed into this method is a user right, not an action name.
2630                 // There is no way to instantiate an action by restriction. However, this
2631                 // will get the action where the restriction is the same. This may result
2632                 // in actions being blocked that shouldn't be.
2633                 $actionObj = null;
2634                 if ( Action::exists( $action ) ) {
2635                         // Clone the title to prevent mutations to this object which is done
2636                         // by Title::loadFromRow() in WikiPage::loadFromRow().
2637                         $page = WikiPage::factory( clone $this );
2638                         // Creating an action will perform several database queries to ensure that
2639                         // the action has not been overridden by the content type.
2640                         // @todo FIXME: Pass the relevant context into this function.
2641                         $actionObj = Action::factory( $action, $page, RequestContext::getMain() );
2642                         // Ensure that the retrieved action matches the restriction.
2643                         if ( $actionObj && $actionObj->getRestriction() !== $action ) {
2644                                 $actionObj = null;
2645                         }
2646                 }
2647
2648                 // If no action object is returned, assume that the action requires unblock
2649                 // which is the default.
2650                 if ( !$actionObj || $actionObj->requiresUnblock() ) {
2651                         if ( $user->isBlockedFrom( $this, $useReplica ) ) {
2652                                 // @todo FIXME: Pass the relevant context into this function.
2653                                 $errors[] = $block
2654                                         ? $block->getPermissionsError( RequestContext::getMain() )
2655                                         : [ 'actionblockedtext' ];
2656                         }
2657                 }
2658
2659                 return $errors;
2660         }
2661
2662         /**
2663          * Check that the user is allowed to read this page.
2664          *
2665          * @param string $action The action to check
2666          * @param User $user User to check
2667          * @param array $errors List of current errors
2668          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2669          * @param bool $short Short circuit on first error
2670          *
2671          * @return array List of errors
2672          */
2673         private function checkReadPermissions( $action, $user, $errors, $rigor, $short ) {
2674                 global $wgWhitelistRead, $wgWhitelistReadRegexp;
2675
2676                 $whitelisted = false;
2677                 if ( User::isEveryoneAllowed( 'read' ) ) {
2678                         # Shortcut for public wikis, allows skipping quite a bit of code
2679                         $whitelisted = true;
2680                 } elseif ( $user->isAllowed( 'read' ) ) {
2681                         # If the user is allowed to read pages, he is allowed to read all pages
2682                         $whitelisted = true;
2683                 } elseif ( $this->isSpecial( 'Userlogin' )
2684                         || $this->isSpecial( 'PasswordReset' )
2685                         || $this->isSpecial( 'Userlogout' )
2686                 ) {
2687                         # Always grant access to the login page.
2688                         # Even anons need to be able to log in.
2689                         $whitelisted = true;
2690                 } elseif ( is_array( $wgWhitelistRead ) && count( $wgWhitelistRead ) ) {
2691                         # Time to check the whitelist
2692                         # Only do these checks is there's something to check against
2693                         $name = $this->getPrefixedText();
2694                         $dbName = $this->getPrefixedDBkey();
2695
2696                         // Check for explicit whitelisting with and without underscores
2697                         if ( in_array( $name, $wgWhitelistRead, true ) || in_array( $dbName, $wgWhitelistRead, true ) ) {
2698                                 $whitelisted = true;
2699                         } elseif ( $this->mNamespace == NS_MAIN ) {
2700                                 # Old settings might have the title prefixed with
2701                                 # a colon for main-namespace pages
2702                                 if ( in_array( ':' . $name, $wgWhitelistRead ) ) {
2703                                         $whitelisted = true;
2704                                 }
2705                         } elseif ( $this->isSpecialPage() ) {
2706                                 # If it's a special page, ditch the subpage bit and check again
2707                                 $name = $this->mDbkeyform;
2708                                 list( $name, /* $subpage */ ) =
2709                                         MediaWikiServices::getInstance()->getSpecialPageFactory()->
2710                                                 resolveAlias( $name );
2711                                 if ( $name ) {
2712                                         $pure = SpecialPage::getTitleFor( $name )->getPrefixedText();
2713                                         if ( in_array( $pure, $wgWhitelistRead, true ) ) {
2714                                                 $whitelisted = true;
2715                                         }
2716                                 }
2717                         }
2718                 }
2719
2720                 if ( !$whitelisted && is_array( $wgWhitelistReadRegexp ) && !empty( $wgWhitelistReadRegexp ) ) {
2721                         $name = $this->getPrefixedText();
2722                         // Check for regex whitelisting
2723                         foreach ( $wgWhitelistReadRegexp as $listItem ) {
2724                                 if ( preg_match( $listItem, $name ) ) {
2725                                         $whitelisted = true;
2726                                         break;
2727                                 }
2728                         }
2729                 }
2730
2731                 if ( !$whitelisted ) {
2732                         # If the title is not whitelisted, give extensions a chance to do so...
2733                         Hooks::run( 'TitleReadWhitelist', [ $this, $user, &$whitelisted ] );
2734                         if ( !$whitelisted ) {
2735                                 $errors[] = $this->missingPermissionError( $action, $short );
2736                         }
2737                 }
2738
2739                 return $errors;
2740         }
2741
2742         /**
2743          * Get a description array when the user doesn't have the right to perform
2744          * $action (i.e. when User::isAllowed() returns false)
2745          *
2746          * @param string $action The action to check
2747          * @param bool $short Short circuit on first error
2748          * @return array Array containing an error message key and any parameters
2749          */
2750         private function missingPermissionError( $action, $short ) {
2751                 // We avoid expensive display logic for quickUserCan's and such
2752                 if ( $short ) {
2753                         return [ 'badaccess-group0' ];
2754                 }
2755
2756                 return User::newFatalPermissionDeniedStatus( $action )->getErrorsArray()[0];
2757         }
2758
2759         /**
2760          * Can $user perform $action on this page? This is an internal function,
2761          * with multiple levels of checks depending on performance needs; see $rigor below.
2762          * It does not check wfReadOnly().
2763          *
2764          * @param string $action Action that permission needs to be checked for
2765          * @param User $user User to check
2766          * @param string $rigor One of (quick,full,secure)
2767          *   - quick  : does cheap permission checks from replica DBs (usable for GUI creation)
2768          *   - full   : does cheap and expensive checks possibly from a replica DB
2769          *   - secure : does cheap and expensive checks, using the master as needed
2770          * @param bool $short Set this to true to stop after the first permission error.
2771          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
2772          */
2773         protected function getUserPermissionsErrorsInternal(
2774                 $action, $user, $rigor = 'secure', $short = false
2775         ) {
2776                 if ( $rigor === true ) {
2777                         $rigor = 'secure'; // b/c
2778                 } elseif ( $rigor === false ) {
2779                         $rigor = 'quick'; // b/c
2780                 } elseif ( !in_array( $rigor, [ 'quick', 'full', 'secure' ] ) ) {
2781                         throw new Exception( "Invalid rigor parameter '$rigor'." );
2782                 }
2783
2784                 # Read has special handling
2785                 if ( $action == 'read' ) {
2786                         $checks = [
2787                                 'checkPermissionHooks',
2788                                 'checkReadPermissions',
2789                                 'checkUserBlock', // for wgBlockDisablesLogin
2790                         ];
2791                 # Don't call checkSpecialsAndNSPermissions, checkSiteConfigPermissions
2792                 # or checkUserConfigPermissions here as it will lead to duplicate
2793                 # error messages. This is okay to do since anywhere that checks for
2794                 # create will also check for edit, and those checks are called for edit.
2795                 } elseif ( $action == 'create' ) {
2796                         $checks = [
2797                                 'checkQuickPermissions',
2798                                 'checkPermissionHooks',
2799                                 'checkPageRestrictions',
2800                                 'checkCascadingSourcesRestrictions',
2801                                 'checkActionPermissions',
2802                                 'checkUserBlock'
2803                         ];
2804                 } else {
2805                         $checks = [
2806                                 'checkQuickPermissions',
2807                                 'checkPermissionHooks',
2808                                 'checkSpecialsAndNSPermissions',
2809                                 'checkSiteConfigPermissions',
2810                                 'checkUserConfigPermissions',
2811                                 'checkPageRestrictions',
2812                                 'checkCascadingSourcesRestrictions',
2813                                 'checkActionPermissions',
2814                                 'checkUserBlock'
2815                         ];
2816                 }
2817
2818                 $errors = [];
2819                 foreach ( $checks as $method ) {
2820                         $errors = $this->$method( $action, $user, $errors, $rigor, $short );
2821
2822                         if ( $short && $errors !== [] ) {
2823                                 break;
2824                         }
2825                 }
2826
2827                 return $errors;
2828         }
2829
2830         /**
2831          * Get a filtered list of all restriction types supported by this wiki.
2832          * @param bool $exists True to get all restriction types that apply to
2833          * titles that do exist, False for all restriction types that apply to
2834          * titles that do not exist
2835          * @return array
2836          */
2837         public static function getFilteredRestrictionTypes( $exists = true ) {
2838                 global $wgRestrictionTypes;
2839                 $types = $wgRestrictionTypes;
2840                 if ( $exists ) {
2841                         # Remove the create restriction for existing titles
2842                         $types = array_diff( $types, [ 'create' ] );
2843                 } else {
2844                         # Only the create and upload restrictions apply to non-existing titles
2845                         $types = array_intersect( $types, [ 'create', 'upload' ] );
2846                 }
2847                 return $types;
2848         }
2849
2850         /**
2851          * Returns restriction types for the current Title
2852          *
2853          * @return array Applicable restriction types
2854          */
2855         public function getRestrictionTypes() {
2856                 if ( $this->isSpecialPage() ) {
2857                         return [];
2858                 }
2859
2860                 $types = self::getFilteredRestrictionTypes( $this->exists() );
2861
2862                 if ( $this->mNamespace != NS_FILE ) {
2863                         # Remove the upload restriction for non-file titles
2864                         $types = array_diff( $types, [ 'upload' ] );
2865                 }
2866
2867                 Hooks::run( 'TitleGetRestrictionTypes', [ $this, &$types ] );
2868
2869                 wfDebug( __METHOD__ . ': applicable restrictions to [[' .
2870                         $this->getPrefixedText() . ']] are {' . implode( ',', $types ) . "}\n" );
2871
2872                 return $types;
2873         }
2874
2875         /**
2876          * Is this title subject to title protection?
2877          * Title protection is the one applied against creation of such title.
2878          *
2879          * @return array|bool An associative array representing any existent title
2880          *   protection, or false if there's none.
2881          */
2882         public function getTitleProtection() {
2883                 $protection = $this->getTitleProtectionInternal();
2884                 if ( $protection ) {
2885                         if ( $protection['permission'] == 'sysop' ) {
2886                                 $protection['permission'] = 'editprotected'; // B/C
2887                         }
2888                         if ( $protection['permission'] == 'autoconfirmed' ) {
2889                                 $protection['permission'] = 'editsemiprotected'; // B/C
2890                         }
2891                 }
2892                 return $protection;
2893         }
2894
2895         /**
2896          * Fetch title protection settings
2897          *
2898          * To work correctly, $this->loadRestrictions() needs to have access to the
2899          * actual protections in the database without munging 'sysop' =>
2900          * 'editprotected' and 'autoconfirmed' => 'editsemiprotected'. Other
2901          * callers probably want $this->getTitleProtection() instead.
2902          *
2903          * @return array|bool
2904          */
2905         protected function getTitleProtectionInternal() {
2906                 // Can't protect pages in special namespaces
2907                 if ( $this->mNamespace < 0 ) {
2908                         return false;
2909                 }
2910
2911                 // Can't protect pages that exist.
2912                 if ( $this->exists() ) {
2913                         return false;
2914                 }
2915
2916                 if ( $this->mTitleProtection === null ) {
2917                         $dbr = wfGetDB( DB_REPLICA );
2918                         $commentStore = CommentStore::getStore();
2919                         $commentQuery = $commentStore->getJoin( 'pt_reason' );
2920                         $res = $dbr->select(
2921                                 [ 'protected_titles' ] + $commentQuery['tables'],
2922                                 [
2923                                         'user' => 'pt_user',
2924                                         'expiry' => 'pt_expiry',
2925                                         'permission' => 'pt_create_perm'
2926                                 ] + $commentQuery['fields'],
2927                                 [ 'pt_namespace' => $this->mNamespace, 'pt_title' => $this->mDbkeyform ],
2928                                 __METHOD__,
2929                                 [],
2930                                 $commentQuery['joins']
2931                         );
2932
2933                         // fetchRow returns false if there are no rows.
2934                         $row = $dbr->fetchRow( $res );
2935                         if ( $row ) {
2936                                 $this->mTitleProtection = [
2937                                         'user' => $row['user'],
2938                                         'expiry' => $dbr->decodeExpiry( $row['expiry'] ),
2939                                         'permission' => $row['permission'],
2940                                         'reason' => $commentStore->getComment( 'pt_reason', $row )->text,
2941                                 ];
2942                         } else {
2943                                 $this->mTitleProtection = false;
2944                         }
2945                 }
2946                 return $this->mTitleProtection;
2947         }
2948
2949         /**
2950          * Remove any title protection due to page existing
2951          */
2952         public function deleteTitleProtection() {
2953                 $dbw = wfGetDB( DB_MASTER );
2954
2955                 $dbw->delete(
2956                         'protected_titles',
2957                         [ 'pt_namespace' => $this->mNamespace, 'pt_title' => $this->mDbkeyform ],
2958                         __METHOD__
2959                 );
2960                 $this->mTitleProtection = false;
2961         }
2962
2963         /**
2964          * Is this page "semi-protected" - the *only* protection levels are listed
2965          * in $wgSemiprotectedRestrictionLevels?
2966          *
2967          * @param string $action Action to check (default: edit)
2968          * @return bool
2969          */
2970         public function isSemiProtected( $action = 'edit' ) {
2971                 global $wgSemiprotectedRestrictionLevels;
2972
2973                 $restrictions = $this->getRestrictions( $action );
2974                 $semi = $wgSemiprotectedRestrictionLevels;
2975                 if ( !$restrictions || !$semi ) {
2976                         // Not protected, or all protection is full protection
2977                         return false;
2978                 }
2979
2980                 // Remap autoconfirmed to editsemiprotected for BC
2981                 foreach ( array_keys( $semi, 'autoconfirmed' ) as $key ) {
2982                         $semi[$key] = 'editsemiprotected';
2983                 }
2984                 foreach ( array_keys( $restrictions, 'autoconfirmed' ) as $key ) {
2985                         $restrictions[$key] = 'editsemiprotected';
2986                 }
2987
2988                 return !array_diff( $restrictions, $semi );
2989         }
2990
2991         /**
2992          * Does the title correspond to a protected article?
2993          *
2994          * @param string $action The action the page is protected from,
2995          * by default checks all actions.
2996          * @return bool
2997          */
2998         public function isProtected( $action = '' ) {
2999                 global $wgRestrictionLevels;
3000
3001                 $restrictionTypes = $this->getRestrictionTypes();
3002
3003                 # Special pages have inherent protection
3004                 if ( $this->isSpecialPage() ) {
3005                         return true;
3006                 }
3007
3008                 # Check regular protection levels
3009                 foreach ( $restrictionTypes as $type ) {
3010                         if ( $action == $type || $action == '' ) {
3011                                 $r = $this->getRestrictions( $type );
3012                                 foreach ( $wgRestrictionLevels as $level ) {
3013                                         if ( in_array( $level, $r ) && $level != '' ) {
3014                                                 return true;
3015                                         }
3016                                 }
3017                         }
3018                 }
3019
3020                 return false;
3021         }
3022
3023         /**
3024          * Determines if $user is unable to edit this page because it has been protected
3025          * by $wgNamespaceProtection.
3026          *
3027          * @param User $user User object to check permissions
3028          * @return bool
3029          */
3030         public function isNamespaceProtected( User $user ) {
3031                 global $wgNamespaceProtection;
3032
3033                 if ( isset( $wgNamespaceProtection[$this->mNamespace] ) ) {
3034                         foreach ( (array)$wgNamespaceProtection[$this->mNamespace] as $right ) {
3035                                 if ( $right != '' && !$user->isAllowed( $right ) ) {
3036                                         return true;
3037                                 }
3038                         }
3039                 }
3040                 return false;
3041         }
3042
3043         /**
3044          * Cascading protection: Return true if cascading restrictions apply to this page, false if not.
3045          *
3046          * @return bool If the page is subject to cascading restrictions.
3047          */
3048         public function isCascadeProtected() {
3049                 list( $sources, /* $restrictions */ ) = $this->getCascadeProtectionSources( false );
3050                 return ( $sources > 0 );
3051         }
3052
3053         /**
3054          * Determines whether cascading protection sources have already been loaded from
3055          * the database.
3056          *
3057          * @param bool $getPages True to check if the pages are loaded, or false to check
3058          * if the status is loaded.
3059          * @return bool Whether or not the specified information has been loaded
3060          * @since 1.23
3061          */
3062         public function areCascadeProtectionSourcesLoaded( $getPages = true ) {
3063                 return $getPages ? $this->mCascadeSources !== null : $this->mHasCascadingRestrictions !== null;
3064         }
3065
3066         /**
3067          * Cascading protection: Get the source of any cascading restrictions on this page.
3068          *
3069          * @param bool $getPages Whether or not to retrieve the actual pages
3070          *        that the restrictions have come from and the actual restrictions
3071          *        themselves.
3072          * @return array Two elements: First is an array of Title objects of the
3073          *        pages from which cascading restrictions have come, false for
3074          *        none, or true if such restrictions exist but $getPages was not
3075          *        set. Second is an array like that returned by
3076          *        Title::getAllRestrictions(), or an empty array if $getPages is
3077          *        false.
3078          */
3079         public function getCascadeProtectionSources( $getPages = true ) {
3080                 $pagerestrictions = [];
3081
3082                 if ( $this->mCascadeSources !== null && $getPages ) {
3083                         return [ $this->mCascadeSources, $this->mCascadingRestrictions ];
3084                 } elseif ( $this->mHasCascadingRestrictions !== null && !$getPages ) {
3085                         return [ $this->mHasCascadingRestrictions, $pagerestrictions ];
3086                 }
3087
3088                 $dbr = wfGetDB( DB_REPLICA );
3089
3090                 if ( $this->mNamespace == NS_FILE ) {
3091                         $tables = [ 'imagelinks', 'page_restrictions' ];
3092                         $where_clauses = [
3093                                 'il_to' => $this->mDbkeyform,
3094                                 'il_from=pr_page',
3095                                 'pr_cascade' => 1
3096                         ];
3097                 } else {
3098                         $tables = [ 'templatelinks', 'page_restrictions' ];
3099                         $where_clauses = [
3100                                 'tl_namespace' => $this->mNamespace,
3101                                 'tl_title' => $this->mDbkeyform,
3102                                 'tl_from=pr_page',
3103                                 'pr_cascade' => 1
3104                         ];
3105                 }
3106
3107                 if ( $getPages ) {
3108                         $cols = [ 'pr_page', 'page_namespace', 'page_title',
3109                                 'pr_expiry', 'pr_type', 'pr_level' ];
3110                         $where_clauses[] = 'page_id=pr_page';
3111                         $tables[] = 'page';
3112                 } else {
3113                         $cols = [ 'pr_expiry' ];
3114                 }
3115
3116                 $res = $dbr->select( $tables, $cols, $where_clauses, __METHOD__ );
3117
3118                 $sources = $getPages ? [] : false;
3119                 $now = wfTimestampNow();
3120
3121                 foreach ( $res as $row ) {
3122                         $expiry = $dbr->decodeExpiry( $row->pr_expiry );
3123                         if ( $expiry > $now ) {
3124                                 if ( $getPages ) {
3125                                         $page_id = $row->pr_page;
3126                                         $page_ns = $row->page_namespace;
3127                                         $page_title = $row->page_title;
3128                                         $sources[$page_id] = self::makeTitle( $page_ns, $page_title );
3129                                         # Add groups needed for each restriction type if its not already there
3130                                         # Make sure this restriction type still exists
3131
3132                                         if ( !isset( $pagerestrictions[$row->pr_type] ) ) {
3133                                                 $pagerestrictions[$row->pr_type] = [];
3134                                         }
3135
3136                                         if (
3137                                                 isset( $pagerestrictions[$row->pr_type] )
3138                                                 && !in_array( $row->pr_level, $pagerestrictions[$row->pr_type] )
3139                                         ) {
3140                                                 $pagerestrictions[$row->pr_type][] = $row->pr_level;
3141                                         }
3142                                 } else {
3143                                         $sources = true;
3144                                 }
3145                         }
3146                 }
3147
3148                 if ( $getPages ) {
3149                         $this->mCascadeSources = $sources;
3150                         $this->mCascadingRestrictions = $pagerestrictions;
3151                 } else {
3152                         $this->mHasCascadingRestrictions = $sources;
3153                 }
3154
3155                 return [ $sources, $pagerestrictions ];
3156         }
3157
3158         /**
3159          * Accessor for mRestrictionsLoaded
3160          *
3161          * @return bool Whether or not the page's restrictions have already been
3162          * loaded from the database
3163          * @since 1.23
3164          */
3165         public function areRestrictionsLoaded() {
3166                 return $this->mRestrictionsLoaded;
3167         }
3168
3169         /**
3170          * Accessor/initialisation for mRestrictions
3171          *
3172          * @param string $action Action that permission needs to be checked for
3173          * @return array Restriction levels needed to take the action. All levels are
3174          *     required. Note that restriction levels are normally user rights, but 'sysop'
3175          *     and 'autoconfirmed' are also allowed for backwards compatibility. These should
3176          *     be mapped to 'editprotected' and 'editsemiprotected' respectively.
3177          */
3178         public function getRestrictions( $action ) {
3179                 if ( !$this->mRestrictionsLoaded ) {
3180                         $this->loadRestrictions();
3181                 }
3182                 return $this->mRestrictions[$action] ?? [];
3183         }
3184
3185         /**
3186          * Accessor/initialisation for mRestrictions
3187          *
3188          * @return array Keys are actions, values are arrays as returned by
3189          *     Title::getRestrictions()
3190          * @since 1.23
3191          */
3192         public function getAllRestrictions() {
3193                 if ( !$this->mRestrictionsLoaded ) {
3194                         $this->loadRestrictions();
3195                 }
3196                 return $this->mRestrictions;
3197         }
3198
3199         /**
3200          * Get the expiry time for the restriction against a given action
3201          *
3202          * @param string $action
3203          * @return string|bool 14-char timestamp, or 'infinity' if the page is protected forever
3204          *     or not protected at all, or false if the action is not recognised.
3205          */
3206         public function getRestrictionExpiry( $action ) {
3207                 if ( !$this->mRestrictionsLoaded ) {
3208                         $this->loadRestrictions();
3209                 }
3210                 return $this->mRestrictionsExpiry[$action] ?? false;
3211         }
3212
3213         /**
3214          * Returns cascading restrictions for the current article
3215          *
3216          * @return bool
3217          */
3218         function areRestrictionsCascading() {
3219                 if ( !$this->mRestrictionsLoaded ) {
3220                         $this->loadRestrictions();
3221                 }
3222
3223                 return $this->mCascadeRestriction;
3224         }
3225
3226         /**
3227          * Compiles list of active page restrictions from both page table (pre 1.10)
3228          * and page_restrictions table for this existing page.
3229          * Public for usage by LiquidThreads.
3230          *
3231          * @param array $rows Array of db result objects
3232          * @param string|null $oldFashionedRestrictions Comma-separated set of permission keys
3233          * indicating who can move or edit the page from the page table, (pre 1.10) rows.
3234          * Edit and move sections are separated by a colon
3235          * Example: "edit=autoconfirmed,sysop:move=sysop"
3236          */
3237         public function loadRestrictionsFromRows( $rows, $oldFashionedRestrictions = null ) {
3238                 // This function will only read rows from a table that we migrated away
3239                 // from before adding READ_LATEST support to loadRestrictions, so we
3240                 // don't need to support reading from DB_MASTER here.
3241                 $dbr = wfGetDB( DB_REPLICA );
3242
3243                 $restrictionTypes = $this->getRestrictionTypes();
3244
3245                 foreach ( $restrictionTypes as $type ) {
3246                         $this->mRestrictions[$type] = [];
3247                         $this->mRestrictionsExpiry[$type] = 'infinity';
3248                 }
3249
3250                 $this->mCascadeRestriction = false;
3251
3252                 # Backwards-compatibility: also load the restrictions from the page record (old format).
3253                 if ( $oldFashionedRestrictions !== null ) {
3254                         $this->mOldRestrictions = $oldFashionedRestrictions;
3255                 }
3256
3257                 if ( $this->mOldRestrictions === false ) {
3258                         $this->mOldRestrictions = $dbr->selectField( 'page', 'page_restrictions',
3259                                 [ 'page_id' => $this->getArticleID() ], __METHOD__ );
3260                 }
3261
3262                 if ( $this->mOldRestrictions != '' ) {
3263                         foreach ( explode( ':', trim( $this->mOldRestrictions ) ) as $restrict ) {
3264                                 $temp = explode( '=', trim( $restrict ) );
3265                                 if ( count( $temp ) == 1 ) {
3266                                         // old old format should be treated as edit/move restriction
3267                                         $this->mRestrictions['edit'] = explode( ',', trim( $temp[0] ) );
3268                                         $this->mRestrictions['move'] = explode( ',', trim( $temp[0] ) );
3269                                 } else {
3270                                         $restriction = trim( $temp[1] );
3271                                         if ( $restriction != '' ) { // some old entries are empty
3272                                                 $this->mRestrictions[$temp[0]] = explode( ',', $restriction );
3273                                         }
3274                                 }
3275                         }
3276                 }
3277
3278                 if ( count( $rows ) ) {
3279                         # Current system - load second to make them override.
3280                         $now = wfTimestampNow();
3281
3282                         # Cycle through all the restrictions.
3283                         foreach ( $rows as $row ) {
3284                                 // Don't take care of restrictions types that aren't allowed
3285                                 if ( !in_array( $row->pr_type, $restrictionTypes ) ) {
3286                                         continue;
3287                                 }
3288
3289                                 $expiry = $dbr->decodeExpiry( $row->pr_expiry );
3290
3291                                 // Only apply the restrictions if they haven't expired!
3292                                 if ( !$expiry || $expiry > $now ) {
3293                                         $this->mRestrictionsExpiry[$row->pr_type] = $expiry;
3294                                         $this->mRestrictions[$row->pr_type] = explode( ',', trim( $row->pr_level ) );
3295
3296                                         $this->mCascadeRestriction |= $row->pr_cascade;
3297                                 }
3298                         }
3299                 }
3300
3301                 $this->mRestrictionsLoaded = true;
3302         }
3303
3304         /**
3305          * Load restrictions from the page_restrictions table
3306          *
3307          * @param string|null $oldFashionedRestrictions Comma-separated set of permission keys
3308          * indicating who can move or edit the page from the page table, (pre 1.10) rows.
3309          * Edit and move sections are separated by a colon
3310          * Example: "edit=autoconfirmed,sysop:move=sysop"
3311          * @param int $flags A bit field. If self::READ_LATEST is set, skip replicas and read
3312          *  from the master DB.
3313          */
3314         public function loadRestrictions( $oldFashionedRestrictions = null, $flags = 0 ) {
3315                 $readLatest = DBAccessObjectUtils::hasFlags( $flags, self::READ_LATEST );
3316                 if ( $this->mRestrictionsLoaded && !$readLatest ) {
3317                         return;
3318                 }
3319
3320                 // TODO: should probably pass $flags into getArticleID, but it seems hacky
3321                 // to mix READ_LATEST and GAID_FOR_UPDATE, even if they have the same value.
3322                 // Maybe deprecate GAID_FOR_UPDATE now that we implement IDBAccessObject?
3323                 $id = $this->getArticleID();
3324                 if ( $id ) {
3325                         $fname = __METHOD__;
3326                         $loadRestrictionsFromDb = function ( Database $dbr ) use ( $fname, $id ) {
3327                                 return iterator_to_array(
3328                                         $dbr->select(
3329                                                 'page_restrictions',
3330                                                 [ 'pr_type', 'pr_expiry', 'pr_level', 'pr_cascade' ],
3331                                                 [ 'pr_page' => $id ],
3332                                                 $fname
3333                                         )
3334                                 );
3335                         };
3336
3337                         if ( $readLatest ) {
3338                                 $dbr = wfGetDB( DB_MASTER );
3339                                 $rows = $loadRestrictionsFromDb( $dbr );
3340                         } else {
3341                                 $cache = ObjectCache::getMainWANInstance();
3342                                 $rows = $cache->getWithSetCallback(
3343                                         // Page protections always leave a new null revision
3344                                         $cache->makeKey( 'page-restrictions', $id, $this->getLatestRevID() ),
3345                                         $cache::TTL_DAY,
3346                                         function ( $curValue, &$ttl, array &$setOpts ) use ( $loadRestrictionsFromDb ) {
3347                                                 $dbr = wfGetDB( DB_REPLICA );
3348
3349                                                 $setOpts += Database::getCacheSetOptions( $dbr );
3350
3351                                                 return $loadRestrictionsFromDb( $dbr );
3352                                         }
3353                                 );
3354                         }
3355
3356                         $this->loadRestrictionsFromRows( $rows, $oldFashionedRestrictions );
3357                 } else {
3358                         $title_protection = $this->getTitleProtectionInternal();
3359
3360                         if ( $title_protection ) {
3361                                 $now = wfTimestampNow();
3362                                 $expiry = wfGetDB( DB_REPLICA )->decodeExpiry( $title_protection['expiry'] );
3363
3364                                 if ( !$expiry || $expiry > $now ) {
3365                                         // Apply the restrictions
3366                                         $this->mRestrictionsExpiry['create'] = $expiry;
3367                                         $this->mRestrictions['create'] =
3368                                                 explode( ',', trim( $title_protection['permission'] ) );
3369                                 } else { // Get rid of the old restrictions
3370                                         $this->mTitleProtection = false;
3371                                 }
3372                         } else {
3373                                 $this->mRestrictionsExpiry['create'] = 'infinity';
3374                         }
3375                         $this->mRestrictionsLoaded = true;
3376                 }
3377         }
3378
3379         /**
3380          * Flush the protection cache in this object and force reload from the database.
3381          * This is used when updating protection from WikiPage::doUpdateRestrictions().
3382          */
3383         public function flushRestrictions() {
3384                 $this->mRestrictionsLoaded = false;
3385                 $this->mTitleProtection = null;
3386         }
3387
3388         /**
3389          * Purge expired restrictions from the page_restrictions table
3390          *
3391          * This will purge no more than $wgUpdateRowsPerQuery page_restrictions rows
3392          */
3393         static function purgeExpiredRestrictions() {
3394                 if ( wfReadOnly() ) {
3395                         return;
3396                 }
3397
3398                 DeferredUpdates::addUpdate( new AtomicSectionUpdate(
3399                         wfGetDB( DB_MASTER ),
3400                         __METHOD__,
3401                         function ( IDatabase $dbw, $fname ) {
3402                                 $config = MediaWikiServices::getInstance()->getMainConfig();
3403                                 $ids = $dbw->selectFieldValues(
3404                                         'page_restrictions',
3405                                         'pr_id',
3406                                         [ 'pr_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ],
3407                                         $fname,
3408                                         [ 'LIMIT' => $config->get( 'UpdateRowsPerQuery' ) ] // T135470
3409                                 );
3410                                 if ( $ids ) {
3411                                         $dbw->delete( 'page_restrictions', [ 'pr_id' => $ids ], $fname );
3412                                 }
3413                         }
3414                 ) );
3415
3416                 DeferredUpdates::addUpdate( new AtomicSectionUpdate(
3417                         wfGetDB( DB_MASTER ),
3418                         __METHOD__,
3419                         function ( IDatabase $dbw, $fname ) {
3420                                 $dbw->delete(
3421                                         'protected_titles',
3422                                         [ 'pt_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ],
3423                                         $fname
3424                                 );
3425                         }
3426                 ) );
3427         }
3428
3429         /**
3430          * Does this have subpages?  (Warning, usually requires an extra DB query.)
3431          *
3432          * @return bool
3433          */
3434         public function hasSubpages() {
3435                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
3436                         # Duh
3437                         return false;
3438                 }
3439
3440                 # We dynamically add a member variable for the purpose of this method
3441                 # alone to cache the result.  There's no point in having it hanging
3442                 # around uninitialized in every Title object; therefore we only add it
3443                 # if needed and don't declare it statically.
3444                 if ( $this->mHasSubpages === null ) {
3445                         $this->mHasSubpages = false;
3446                         $subpages = $this->getSubpages( 1 );
3447                         if ( $subpages instanceof TitleArray ) {
3448                                 $this->mHasSubpages = (bool)$subpages->count();
3449                         }
3450                 }
3451
3452                 return $this->mHasSubpages;
3453         }
3454
3455         /**
3456          * Get all subpages of this page.
3457          *
3458          * @param int $limit Maximum number of subpages to fetch; -1 for no limit
3459          * @return TitleArray|array TitleArray, or empty array if this page's namespace
3460          *  doesn't allow subpages
3461          */
3462         public function getSubpages( $limit = -1 ) {
3463                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
3464                         return [];
3465                 }
3466
3467                 $dbr = wfGetDB( DB_REPLICA );
3468                 $conds['page_namespace'] = $this->mNamespace;
3469                 $conds[] = 'page_title ' . $dbr->buildLike( $this->mDbkeyform . '/', $dbr->anyString() );
3470                 $options = [];
3471                 if ( $limit > -1 ) {
3472                         $options['LIMIT'] = $limit;
3473                 }
3474                 return TitleArray::newFromResult(
3475                         $dbr->select( 'page',
3476                                 [ 'page_id', 'page_namespace', 'page_title', 'page_is_redirect' ],
3477                                 $conds,
3478                                 __METHOD__,
3479                                 $options
3480                         )
3481                 );
3482         }
3483
3484         /**
3485          * Is there a version of this page in the deletion archive?
3486          *
3487          * @return int The number of archived revisions
3488          */
3489         public function isDeleted() {
3490                 if ( $this->mNamespace < 0 ) {
3491                         $n = 0;
3492                 } else {
3493                         $dbr = wfGetDB( DB_REPLICA );
3494
3495                         $n = $dbr->selectField( 'archive', 'COUNT(*)',
3496                                 [ 'ar_namespace' => $this->mNamespace, 'ar_title' => $this->mDbkeyform ],
3497                                 __METHOD__
3498                         );
3499                         if ( $this->mNamespace == NS_FILE ) {
3500                                 $n += $dbr->selectField( 'filearchive', 'COUNT(*)',
3501                                         [ 'fa_name' => $this->mDbkeyform ],
3502                                         __METHOD__
3503                                 );
3504                         }
3505                 }
3506                 return (int)$n;
3507         }
3508
3509         /**
3510          * Is there a version of this page in the deletion archive?
3511          *
3512          * @return bool
3513          */
3514         public function isDeletedQuick() {
3515                 if ( $this->mNamespace < 0 ) {
3516                         return false;
3517                 }
3518                 $dbr = wfGetDB( DB_REPLICA );
3519                 $deleted = (bool)$dbr->selectField( 'archive', '1',
3520                         [ 'ar_namespace' => $this->mNamespace, 'ar_title' => $this->mDbkeyform ],
3521                         __METHOD__
3522                 );
3523                 if ( !$deleted && $this->mNamespace == NS_FILE ) {
3524                         $deleted = (bool)$dbr->selectField( 'filearchive', '1',
3525                                 [ 'fa_name' => $this->mDbkeyform ],
3526                                 __METHOD__
3527                         );
3528                 }
3529                 return $deleted;
3530         }
3531
3532         /**
3533          * Get the article ID for this Title from the link cache,
3534          * adding it if necessary
3535          *
3536          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select
3537          *  for update
3538          * @return int The ID
3539          */
3540         public function getArticleID( $flags = 0 ) {
3541                 if ( $this->mNamespace < 0 ) {
3542                         $this->mArticleID = 0;
3543                         return $this->mArticleID;
3544                 }
3545                 $linkCache = MediaWikiServices::getInstance()->getLinkCache();
3546                 if ( $flags & self::GAID_FOR_UPDATE ) {
3547                         $oldUpdate = $linkCache->forUpdate( true );
3548                         $linkCache->clearLink( $this );
3549                         $this->mArticleID = $linkCache->addLinkObj( $this );
3550                         $linkCache->forUpdate( $oldUpdate );
3551                 } else {
3552                         if ( $this->mArticleID == -1 ) {
3553                                 $this->mArticleID = $linkCache->addLinkObj( $this );
3554                         }
3555                 }
3556                 return $this->mArticleID;
3557         }
3558
3559         /**
3560          * Is this an article that is a redirect page?
3561          * Uses link cache, adding it if necessary
3562          *
3563          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3564          * @return bool
3565          */
3566         public function isRedirect( $flags = 0 ) {
3567                 if ( !is_null( $this->mRedirect ) ) {
3568                         return $this->mRedirect;
3569                 }
3570                 if ( !$this->getArticleID( $flags ) ) {
3571                         $this->mRedirect = false;
3572                         return $this->mRedirect;
3573                 }
3574
3575                 $linkCache = MediaWikiServices::getInstance()->getLinkCache();
3576                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3577                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'redirect' );
3578                 if ( $cached === null ) {
3579                         # Trust LinkCache's state over our own
3580                         # LinkCache is telling us that the page doesn't exist, despite there being cached
3581                         # data relating to an existing page in $this->mArticleID. Updaters should clear
3582                         # LinkCache as appropriate, or use $flags = Title::GAID_FOR_UPDATE. If that flag is
3583                         # set, then LinkCache will definitely be up to date here, since getArticleID() forces
3584                         # LinkCache to refresh its data from the master.
3585                         $this->mRedirect = false;
3586                         return $this->mRedirect;
3587                 }
3588
3589                 $this->mRedirect = (bool)$cached;
3590
3591                 return $this->mRedirect;
3592         }
3593
3594         /**
3595          * What is the length of this page?
3596          * Uses link cache, adding it if necessary
3597          *
3598          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3599          * @return int
3600          */
3601         public function getLength( $flags = 0 ) {
3602                 if ( $this->mLength != -1 ) {
3603                         return $this->mLength;
3604                 }
3605                 if ( !$this->getArticleID( $flags ) ) {
3606                         $this->mLength = 0;
3607                         return $this->mLength;
3608                 }
3609                 $linkCache = MediaWikiServices::getInstance()->getLinkCache();
3610                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3611                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'length' );
3612                 if ( $cached === null ) {
3613                         # Trust LinkCache's state over our own, as for isRedirect()
3614                         $this->mLength = 0;
3615                         return $this->mLength;
3616                 }
3617
3618                 $this->mLength = intval( $cached );
3619
3620                 return $this->mLength;
3621         }
3622
3623         /**
3624          * What is the page_latest field for this page?
3625          *
3626          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3627          * @return int Int or 0 if the page doesn't exist
3628          */
3629         public function getLatestRevID( $flags = 0 ) {
3630                 if ( !( $flags & self::GAID_FOR_UPDATE ) && $this->mLatestID !== false ) {
3631                         return intval( $this->mLatestID );
3632                 }
3633                 if ( !$this->getArticleID( $flags ) ) {
3634                         $this->mLatestID = 0;
3635                         return $this->mLatestID;
3636                 }
3637                 $linkCache = MediaWikiServices::getInstance()->getLinkCache();
3638                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3639                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'revision' );
3640                 if ( $cached === null ) {
3641                         # Trust LinkCache's state over our own, as for isRedirect()
3642                         $this->mLatestID = 0;
3643                         return $this->mLatestID;
3644                 }
3645
3646                 $this->mLatestID = intval( $cached );
3647
3648                 return $this->mLatestID;
3649         }
3650
3651         /**
3652          * This clears some fields in this object, and clears any associated
3653          * keys in the "bad links" section of the link cache.
3654          *
3655          * - This is called from WikiPage::doEditContent() and WikiPage::insertOn() to allow
3656          * loading of the new page_id. It's also called from
3657          * WikiPage::doDeleteArticleReal()
3658          *
3659          * @param int $newid The new Article ID
3660          */
3661         public function resetArticleID( $newid ) {
3662                 $linkCache = MediaWikiServices::getInstance()->getLinkCache();
3663                 $linkCache->clearLink( $this );
3664
3665                 if ( $newid === false ) {
3666                         $this->mArticleID = -1;
3667                 } else {
3668                         $this->mArticleID = intval( $newid );
3669                 }
3670                 $this->mRestrictionsLoaded = false;
3671                 $this->mRestrictions = [];
3672                 $this->mOldRestrictions = false;
3673                 $this->mRedirect = null;
3674                 $this->mLength = -1;
3675                 $this->mLatestID = false;
3676                 $this->mContentModel = false;
3677                 $this->mEstimateRevisions = null;
3678                 $this->mPageLanguage = false;
3679                 $this->mDbPageLanguage = false;
3680                 $this->mIsBigDeletion = null;
3681         }
3682
3683         public static function clearCaches() {
3684                 $linkCache = MediaWikiServices::getInstance()->getLinkCache();
3685                 $linkCache->clear();
3686
3687                 $titleCache = self::getTitleCache();
3688                 $titleCache->clear();
3689         }
3690
3691         /**
3692          * Capitalize a text string for a title if it belongs to a namespace that capitalizes
3693          *
3694          * @param string $text Containing title to capitalize
3695          * @param int $ns Namespace index, defaults to NS_MAIN
3696          * @return string Containing capitalized title
3697          */
3698         public static function capitalize( $text, $ns = NS_MAIN ) {
3699                 if ( MWNamespace::isCapitalized( $ns ) ) {
3700                         return MediaWikiServices::getInstance()->getContentLanguage()->ucfirst( $text );
3701                 } else {
3702                         return $text;
3703                 }
3704         }
3705
3706         /**
3707          * Secure and split - main initialisation function for this object
3708          *
3709          * Assumes that mDbkeyform has been set, and is urldecoded
3710          * and uses underscores, but not otherwise munged.  This function
3711          * removes illegal characters, splits off the interwiki and
3712          * namespace prefixes, sets the other forms, and canonicalizes
3713          * everything.
3714          *
3715          * @throws MalformedTitleException On invalid titles
3716          * @return bool True on success
3717          */
3718         private function secureAndSplit() {
3719                 // @note: splitTitleString() is a temporary hack to allow MediaWikiTitleCodec to share
3720                 //        the parsing code with Title, while avoiding massive refactoring.
3721                 // @todo: get rid of secureAndSplit, refactor parsing code.
3722                 // @note: getTitleParser() returns a TitleParser implementation which does not have a
3723                 //        splitTitleString method, but the only implementation (MediaWikiTitleCodec) does
3724                 $titleCodec = MediaWikiServices::getInstance()->getTitleParser();
3725                 // MalformedTitleException can be thrown here
3726                 $parts = $titleCodec->splitTitleString( $this->mDbkeyform, $this->mDefaultNamespace );
3727
3728                 # Fill fields
3729                 $this->setFragment( '#' . $parts['fragment'] );
3730                 $this->mInterwiki = $parts['interwiki'];
3731                 $this->mLocalInterwiki = $parts['local_interwiki'];
3732                 $this->mNamespace = $parts['namespace'];
3733                 $this->mUserCaseDBKey = $parts['user_case_dbkey'];
3734
3735                 $this->mDbkeyform = $parts['dbkey'];
3736                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
3737                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
3738
3739                 # We already know that some pages won't be in the database!
3740                 if ( $this->isExternal() || $this->isSpecialPage() ) {
3741                         $this->mArticleID = 0;
3742                 }
3743
3744                 return true;
3745         }
3746
3747         /**
3748          * Get an array of Title objects linking to this Title
3749          * Also stores the IDs in the link cache.
3750          *
3751          * WARNING: do not use this function on arbitrary user-supplied titles!
3752          * On heavily-used templates it will max out the memory.
3753          *
3754          * @param array $options May be FOR UPDATE
3755          * @param string $table Table name
3756          * @param string $prefix Fields prefix
3757          * @return Title[] Array of Title objects linking here
3758          */
3759         public function getLinksTo( $options = [], $table = 'pagelinks', $prefix = 'pl' ) {
3760                 if ( count( $options ) > 0 ) {
3761                         $db = wfGetDB( DB_MASTER );
3762                 } else {
3763                         $db = wfGetDB( DB_REPLICA );
3764                 }
3765
3766                 $res = $db->select(
3767                         [ 'page', $table ],
3768                         self::getSelectFields(),
3769                         [
3770                                 "{$prefix}_from=page_id",
3771                                 "{$prefix}_namespace" => $this->mNamespace,
3772                                 "{$prefix}_title" => $this->mDbkeyform ],
3773                         __METHOD__,
3774                         $options
3775                 );
3776
3777                 $retVal = [];
3778                 if ( $res->numRows() ) {
3779                         $linkCache = MediaWikiServices::getInstance()->getLinkCache();
3780                         foreach ( $res as $row ) {
3781                                 $titleObj = self::makeTitle( $row->page_namespace, $row->page_title );
3782                                 if ( $titleObj ) {
3783                                         $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3784                                         $retVal[] = $titleObj;
3785                                 }
3786                         }
3787                 }
3788                 return $retVal;
3789         }
3790
3791         /**
3792          * Get an array of Title objects using this Title as a template
3793          * Also stores the IDs in the link cache.
3794          *
3795          * WARNING: do not use this function on arbitrary user-supplied titles!
3796          * On heavily-used templates it will max out the memory.
3797          *
3798          * @param array $options Query option to Database::select()
3799          * @return Title[] Array of Title the Title objects linking here
3800          */
3801         public function getTemplateLinksTo( $options = [] ) {
3802                 return $this->getLinksTo( $options, 'templatelinks', 'tl' );
3803         }
3804
3805         /**
3806          * Get an array of Title objects linked from this Title
3807          * Also stores the IDs in the link cache.
3808          *
3809          * WARNING: do not use this function on arbitrary user-supplied titles!
3810          * On heavily-used templates it will max out the memory.
3811          *
3812          * @param array $options Query option to Database::select()
3813          * @param string $table Table name
3814          * @param string $prefix Fields prefix
3815          * @return array Array of Title objects linking here
3816          */
3817         public function getLinksFrom( $options = [], $table = 'pagelinks', $prefix = 'pl' ) {
3818                 $id = $this->getArticleID();
3819
3820                 # If the page doesn't exist; there can't be any link from this page
3821                 if ( !$id ) {
3822                         return [];
3823                 }
3824
3825                 $db = wfGetDB( DB_REPLICA );
3826
3827                 $blNamespace = "{$prefix}_namespace";
3828                 $blTitle = "{$prefix}_title";
3829
3830                 $pageQuery = WikiPage::getQueryInfo();
3831                 $res = $db->select(
3832                         [ $table, 'nestpage' => $pageQuery['tables'] ],
3833                         array_merge(
3834                                 [ $blNamespace, $blTitle ],
3835                                 $pageQuery['fields']
3836                         ),
3837                         [ "{$prefix}_from" => $id ],
3838                         __METHOD__,
3839                         $options,
3840                         [ 'nestpage' => [
3841                                 'LEFT JOIN',
3842                                 [ "page_namespace=$blNamespace", "page_title=$blTitle" ]
3843                         ] ] + $pageQuery['joins']
3844                 );
3845
3846                 $retVal = [];
3847                 $linkCache = MediaWikiServices::getInstance()->getLinkCache();
3848                 foreach ( $res as $row ) {
3849                         if ( $row->page_id ) {
3850                                 $titleObj = self::newFromRow( $row );
3851                         } else {
3852                                 $titleObj = self::makeTitle( $row->$blNamespace, $row->$blTitle );
3853                                 $linkCache->addBadLinkObj( $titleObj );
3854                         }
3855                         $retVal[] = $titleObj;
3856                 }
3857
3858                 return $retVal;
3859         }
3860
3861         /**
3862          * Get an array of Title objects used on this Title as a template
3863          * Also stores the IDs in the link cache.
3864          *
3865          * WARNING: do not use this function on arbitrary user-supplied titles!
3866          * On heavily-used templates it will max out the memory.
3867          *
3868          * @param array $options May be FOR UPDATE
3869          * @return Title[] Array of Title the Title objects used here
3870          */
3871         public function getTemplateLinksFrom( $options = [] ) {
3872                 return $this->getLinksFrom( $options, 'templatelinks', 'tl' );
3873         }
3874
3875         /**
3876          * Get an array of Title objects referring to non-existent articles linked
3877          * from this page.
3878          *
3879          * @todo check if needed (used only in SpecialBrokenRedirects.php, and
3880          *   should use redirect table in this case).
3881          * @return Title[] Array of Title the Title objects
3882          */
3883         public function getBrokenLinksFrom() {
3884                 if ( $this->getArticleID() == 0 ) {
3885                         # All links from article ID 0 are false positives
3886                         return [];
3887                 }
3888
3889                 $dbr = wfGetDB( DB_REPLICA );
3890                 $res = $dbr->select(
3891                         [ 'page', 'pagelinks' ],
3892                         [ 'pl_namespace', 'pl_title' ],
3893                         [
3894                                 'pl_from' => $this->getArticleID(),
3895                                 'page_namespace IS NULL'
3896                         ],
3897                         __METHOD__, [],
3898                         [
3899                                 'page' => [
3900                                         'LEFT JOIN',
3901                                         [ 'pl_namespace=page_namespace', 'pl_title=page_title' ]
3902                                 ]
3903                         ]
3904                 );
3905
3906                 $retVal = [];
3907                 foreach ( $res as $row ) {
3908                         $retVal[] = self::makeTitle( $row->pl_namespace, $row->pl_title );
3909                 }
3910                 return $retVal;
3911         }
3912
3913         /**
3914          * Get a list of URLs to purge from the CDN cache when this
3915          * page changes
3916          *
3917          * @return string[] Array of String the URLs
3918          */
3919         public function getCdnUrls() {
3920                 $urls = [
3921                         $this->getInternalURL(),
3922                         $this->getInternalURL( 'action=history' )
3923                 ];
3924
3925                 $pageLang = $this->getPageLanguage();
3926                 if ( $pageLang->hasVariants() ) {
3927                         $variants = $pageLang->getVariants();
3928                         foreach ( $variants as $vCode ) {
3929                                 $urls[] = $this->getInternalURL( $vCode );
3930                         }
3931                 }
3932
3933                 // If we are looking at a css/js user subpage, purge the action=raw.
3934                 if ( $this->isUserJsConfigPage() ) {
3935                         $urls[] = $this->getInternalURL( 'action=raw&ctype=text/javascript' );
3936                 } elseif ( $this->isUserJsonConfigPage() ) {
3937                         $urls[] = $this->getInternalURL( 'action=raw&ctype=application/json' );
3938                 } elseif ( $this->isUserCssConfigPage() ) {
3939                         $urls[] = $this->getInternalURL( 'action=raw&ctype=text/css' );
3940                 }
3941
3942                 Hooks::run( 'TitleSquidURLs', [ $this, &$urls ] );
3943                 return $urls;
3944         }
3945
3946         /**
3947          * Purge all applicable CDN URLs
3948          */
3949         public function purgeSquid() {
3950                 DeferredUpdates::addUpdate(
3951                         new CdnCacheUpdate( $this->getCdnUrls() ),
3952                         DeferredUpdates::PRESEND
3953                 );
3954         }
3955
3956         /**
3957          * Check whether a given move operation would be valid.
3958          * Returns true if ok, or a getUserPermissionsErrors()-like array otherwise
3959          *
3960          * @deprecated since 1.25, use MovePage's methods instead
3961          * @param Title &$nt The new title
3962          * @param bool $auth Whether to check user permissions (uses $wgUser)
3963          * @param string $reason Is the log summary of the move, used for spam checking
3964          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3965          */
3966         public function isValidMoveOperation( &$nt, $auth = true, $reason = '' ) {
3967                 global $wgUser;
3968
3969                 if ( !( $nt instanceof Title ) ) {
3970                         // Normally we'd add this to $errors, but we'll get
3971                         // lots of syntax errors if $nt is not an object
3972                         return [ [ 'badtitletext' ] ];
3973                 }
3974
3975                 $mp = new MovePage( $this, $nt );
3976                 $errors = $mp->isValidMove()->getErrorsArray();
3977                 if ( $auth ) {
3978                         $errors = wfMergeErrorArrays(
3979                                 $errors,
3980                                 $mp->checkPermissions( $wgUser, $reason )->getErrorsArray()
3981                         );
3982                 }
3983
3984                 return $errors ?: true;
3985         }
3986
3987         /**
3988          * Check if the requested move target is a valid file move target
3989          * @todo move this to MovePage
3990          * @param Title $nt Target title
3991          * @return array List of errors
3992          */
3993         protected function validateFileMoveOperation( $nt ) {
3994                 global $wgUser;
3995
3996                 $errors = [];
3997
3998                 $destFile = wfLocalFile( $nt );
3999                 $destFile->load( File::READ_LATEST );
4000                 if ( !$wgUser->isAllowed( 'reupload-shared' )
4001                         && !$destFile->exists() && wfFindFile( $nt )
4002                 ) {
4003                         $errors[] = [ 'file-exists-sharedrepo' ];
4004                 }
4005
4006                 return $errors;
4007         }
4008
4009         /**
4010          * Move a title to a new location
4011          *
4012          * @deprecated since 1.25, use the MovePage class instead
4013          * @param Title &$nt The new title
4014          * @param bool $auth Indicates whether $wgUser's permissions
4015          *  should be checked
4016          * @param string $reason The reason for the move
4017          * @param bool $createRedirect Whether to create a redirect from the old title to the new title.
4018          *  Ignored if the user doesn't have the suppressredirect right.
4019          * @param array $changeTags Applied to the entry in the move log and redirect page revision
4020          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
4021          */
4022         public function moveTo( &$nt, $auth = true, $reason = '', $createRedirect = true,
4023                 array $changeTags = []
4024         ) {
4025                 global $wgUser;
4026                 $err = $this->isValidMoveOperation( $nt, $auth, $reason );
4027                 if ( is_array( $err ) ) {
4028                         // Auto-block user's IP if the account was "hard" blocked
4029                         $wgUser->spreadAnyEditBlock();
4030                         return $err;
4031                 }
4032                 // Check suppressredirect permission
4033                 if ( $auth && !$wgUser->isAllowed( 'suppressredirect' ) ) {
4034                         $createRedirect = true;
4035                 }
4036
4037                 $mp = new MovePage( $this, $nt );
4038                 $status = $mp->move( $wgUser, $reason, $createRedirect, $changeTags );
4039                 if ( $status->isOK() ) {
4040                         return true;
4041                 } else {
4042                         return $status->getErrorsArray();
4043                 }
4044         }
4045
4046         /**
4047          * Move this page's subpages to be subpages of $nt
4048          *
4049          * @param Title $nt Move target
4050          * @param bool $auth Whether $wgUser's permissions should be checked
4051          * @param string $reason The reason for the move
4052          * @param bool $createRedirect Whether to create redirects from the old subpages to
4053          *     the new ones Ignored if the user doesn't have the 'suppressredirect' right
4054          * @param array $changeTags Applied to the entry in the move log and redirect page revision
4055          * @return array Array with old page titles as keys, and strings (new page titles) or
4056          *     getUserPermissionsErrors()-like arrays (errors) as values, or a
4057          *     getUserPermissionsErrors()-like error array with numeric indices if
4058          *     no pages were moved
4059          */
4060         public function moveSubpages( $nt, $auth = true, $reason = '', $createRedirect = true,
4061                 array $changeTags = []
4062         ) {
4063                 global $wgMaximumMovedPages;
4064                 // Check permissions
4065                 if ( !$this->userCan( 'move-subpages' ) ) {
4066                         return [
4067                                 [ 'cant-move-subpages' ],
4068                         ];
4069                 }
4070                 // Do the source and target namespaces support subpages?
4071                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
4072                         return [
4073                                 [ 'namespace-nosubpages', MWNamespace::getCanonicalName( $this->mNamespace ) ],
4074                         ];
4075                 }
4076                 if ( !MWNamespace::hasSubpages( $nt->getNamespace() ) ) {
4077                         return [
4078                                 [ 'namespace-nosubpages', MWNamespace::getCanonicalName( $nt->getNamespace() ) ],
4079                         ];
4080                 }
4081
4082                 $subpages = $this->getSubpages( $wgMaximumMovedPages + 1 );
4083                 $retval = [];
4084                 $count = 0;
4085                 foreach ( $subpages as $oldSubpage ) {
4086                         $count++;
4087                         if ( $count > $wgMaximumMovedPages ) {
4088                                 $retval[$oldSubpage->getPrefixedText()] = [
4089                                         [ 'movepage-max-pages', $wgMaximumMovedPages ],
4090                                 ];
4091                                 break;
4092                         }
4093
4094                         // We don't know whether this function was called before
4095                         // or after moving the root page, so check both
4096                         // $this and $nt
4097                         if ( $oldSubpage->getArticleID() == $this->getArticleID()
4098                                 || $oldSubpage->getArticleID() == $nt->getArticleID()
4099                         ) {
4100                                 // When moving a page to a subpage of itself,
4101                                 // don't move it twice
4102                                 continue;
4103                         }
4104                         $newPageName = preg_replace(
4105                                         '#^' . preg_quote( $this->mDbkeyform, '#' ) . '#',
4106                                         StringUtils::escapeRegexReplacement( $nt->getDBkey() ), # T23234
4107                                         $oldSubpage->getDBkey() );
4108                         if ( $oldSubpage->isTalkPage() ) {
4109                                 $newNs = $nt->getTalkPage()->getNamespace();
4110                         } else {
4111                                 $newNs = $nt->getSubjectPage()->getNamespace();
4112                         }
4113                         # T16385: we need makeTitleSafe because the new page names may
4114                         # be longer than 255 characters.
4115                         $newSubpage = self::makeTitleSafe( $newNs, $newPageName );
4116
4117                         $success = $oldSubpage->moveTo( $newSubpage, $auth, $reason, $createRedirect, $changeTags );
4118                         if ( $success === true ) {
4119                                 $retval[$oldSubpage->getPrefixedText()] = $newSubpage->getPrefixedText();
4120                         } else {
4121                                 $retval[$oldSubpage->getPrefixedText()] = $success;
4122                         }
4123                 }
4124                 return $retval;
4125         }
4126
4127         /**
4128          * Checks if this page is just a one-rev redirect.
4129          * Adds lock, so don't use just for light purposes.
4130          *
4131          * @return bool
4132          */
4133         public function isSingleRevRedirect() {
4134                 global $wgContentHandlerUseDB;
4135
4136                 $dbw = wfGetDB( DB_MASTER );
4137
4138                 # Is it a redirect?
4139                 $fields = [ 'page_is_redirect', 'page_latest', 'page_id' ];
4140                 if ( $wgContentHandlerUseDB ) {
4141                         $fields[] = 'page_content_model';
4142                 }
4143
4144                 $row = $dbw->selectRow( 'page',
4145                         $fields,
4146                         $this->pageCond(),
4147                         __METHOD__,
4148                         [ 'FOR UPDATE' ]
4149                 );
4150                 # Cache some fields we may want
4151                 $this->mArticleID = $row ? intval( $row->page_id ) : 0;
4152                 $this->mRedirect = $row ? (bool)$row->page_is_redirect : false;
4153                 $this->mLatestID = $row ? intval( $row->page_latest ) : false;
4154                 $this->mContentModel = $row && isset( $row->page_content_model )
4155                         ? strval( $row->page_content_model )
4156                         : false;
4157
4158                 if ( !$this->mRedirect ) {
4159                         return false;
4160                 }
4161                 # Does the article have a history?
4162                 $row = $dbw->selectField( [ 'page', 'revision' ],
4163                         'rev_id',
4164                         [ 'page_namespace' => $this->mNamespace,
4165                                 'page_title' => $this->mDbkeyform,
4166                                 'page_id=rev_page',
4167                                 'page_latest != rev_id'
4168                         ],
4169                         __METHOD__,
4170                         [ 'FOR UPDATE' ]
4171                 );
4172                 # Return true if there was no history
4173                 return ( $row === false );
4174         }
4175
4176         /**
4177          * Checks if $this can be moved to a given Title
4178          * - Selects for update, so don't call it unless you mean business
4179          *
4180          * @deprecated since 1.25, use MovePage's methods instead
4181          * @param Title $nt The new title to check
4182          * @return bool
4183          */
4184         public function isValidMoveTarget( $nt ) {
4185                 # Is it an existing file?
4186                 if ( $nt->getNamespace() == NS_FILE ) {
4187                         $file = wfLocalFile( $nt );
4188                         $file->load( File::READ_LATEST );
4189                         if ( $file->exists() ) {
4190                                 wfDebug( __METHOD__ . ": file exists\n" );
4191                                 return false;
4192                         }
4193                 }
4194                 # Is it a redirect with no history?
4195                 if ( !$nt->isSingleRevRedirect() ) {
4196                         wfDebug( __METHOD__ . ": not a one-rev redirect\n" );
4197                         return false;
4198                 }
4199                 # Get the article text
4200                 $rev = Revision::newFromTitle( $nt, false, Revision::READ_LATEST );
4201                 if ( !is_object( $rev ) ) {
4202                         return false;
4203                 }
4204                 $content = $rev->getContent();
4205                 # Does the redirect point to the source?
4206                 # Or is it a broken self-redirect, usually caused by namespace collisions?
4207                 $redirTitle = $content ? $content->getRedirectTarget() : null;
4208
4209                 if ( $redirTitle ) {
4210                         if ( $redirTitle->getPrefixedDBkey() != $this->getPrefixedDBkey() &&
4211                                 $redirTitle->getPrefixedDBkey() != $nt->getPrefixedDBkey() ) {
4212                                 wfDebug( __METHOD__ . ": redirect points to other page\n" );
4213                                 return false;
4214                         } else {
4215                                 return true;
4216                         }
4217                 } else {
4218                         # Fail safe (not a redirect after all. strange.)
4219                         wfDebug( __METHOD__ . ": failsafe: database sais " . $nt->getPrefixedDBkey() .
4220                                                 " is a redirect, but it doesn't contain a valid redirect.\n" );
4221                         return false;
4222                 }
4223         }
4224
4225         /**
4226          * Get categories to which this Title belongs and return an array of
4227          * categories' names.
4228          *
4229          * @return array Array of parents in the form:
4230          *     $parent => $currentarticle
4231          */
4232         public function getParentCategories() {
4233                 $data = [];
4234
4235                 $titleKey = $this->getArticleID();
4236
4237                 if ( $titleKey === 0 ) {
4238                         return $data;
4239                 }
4240
4241                 $dbr = wfGetDB( DB_REPLICA );
4242
4243                 $res = $dbr->select(
4244                         'categorylinks',
4245                         'cl_to',
4246                         [ 'cl_from' => $titleKey ],
4247                         __METHOD__
4248                 );
4249
4250                 if ( $res->numRows() > 0 ) {
4251                         $contLang = MediaWikiServices::getInstance()->getContentLanguage();
4252                         foreach ( $res as $row ) {
4253                                 // $data[] = Title::newFromText( $contLang->getNsText ( NS_CATEGORY ).':'.$row->cl_to);
4254                                 $data[$contLang->getNsText( NS_CATEGORY ) . ':' . $row->cl_to] =
4255                                         $this->getFullText();
4256                         }
4257                 }
4258                 return $data;
4259         }
4260
4261         /**
4262          * Get a tree of parent categories
4263          *
4264          * @param array $children Array with the children in the keys, to check for circular refs
4265          * @return array Tree of parent categories
4266          */
4267         public function getParentCategoryTree( $children = [] ) {
4268                 $stack = [];
4269                 $parents = $this->getParentCategories();
4270
4271                 if ( $parents ) {
4272                         foreach ( $parents as $parent => $current ) {
4273                                 if ( array_key_exists( $parent, $children ) ) {
4274                                         # Circular reference
4275                                         $stack[$parent] = [];
4276                                 } else {
4277                                         $nt = self::newFromText( $parent );
4278                                         if ( $nt ) {
4279                                                 $stack[$parent] = $nt->getParentCategoryTree( $children + [ $parent => 1 ] );
4280                                         }
4281                                 }
4282                         }
4283                 }
4284
4285                 return $stack;
4286         }
4287
4288         /**
4289          * Get an associative array for selecting this title from
4290          * the "page" table
4291          *
4292          * @return array Array suitable for the $where parameter of DB::select()
4293          */
4294         public function pageCond() {
4295                 if ( $this->mArticleID > 0 ) {
4296                         // PK avoids secondary lookups in InnoDB, shouldn't hurt other DBs
4297                         return [ 'page_id' => $this->mArticleID ];
4298                 } else {
4299                         return [ 'page_namespace' => $this->mNamespace, 'page_title' => $this->mDbkeyform ];
4300                 }
4301         }
4302
4303         /**
4304          * Get next/previous revision ID relative to another revision ID
4305          * @param int $revId Revision ID. Get the revision that was before this one.
4306          * @param int $flags Title::GAID_FOR_UPDATE
4307          * @param string $dir 'next' or 'prev'
4308          * @return int|bool New revision ID, or false if none exists
4309          */
4310         private function getRelativeRevisionID( $revId, $flags, $dir ) {
4311                 $revId = (int)$revId;
4312                 if ( $dir === 'next' ) {
4313                         $op = '>';
4314                         $sort = 'ASC';
4315                 } elseif ( $dir === 'prev' ) {
4316                         $op = '<';
4317                         $sort = 'DESC';
4318                 } else {
4319                         throw new InvalidArgumentException( '$dir must be "next" or "prev"' );
4320                 }
4321
4322                 if ( $flags & self::GAID_FOR_UPDATE ) {
4323                         $db = wfGetDB( DB_MASTER );
4324                 } else {
4325                         $db = wfGetDB( DB_REPLICA, 'contributions' );
4326                 }
4327
4328                 // Intentionally not caring if the specified revision belongs to this
4329                 // page. We only care about the timestamp.
4330                 $ts = $db->selectField( 'revision', 'rev_timestamp', [ 'rev_id' => $revId ], __METHOD__ );
4331                 if ( $ts === false ) {
4332                         $ts = $db->selectField( 'archive', 'ar_timestamp', [ 'ar_rev_id' => $revId ], __METHOD__ );
4333                         if ( $ts === false ) {
4334                                 // Or should this throw an InvalidArgumentException or something?
4335                                 return false;
4336                         }
4337                 }
4338                 $ts = $db->addQuotes( $ts );
4339
4340                 $revId = $db->selectField( 'revision', 'rev_id',
4341                         [
4342                                 'rev_page' => $this->getArticleID( $flags ),
4343                                 "rev_timestamp $op $ts OR (rev_timestamp = $ts AND rev_id $op $revId)"
4344                         ],
4345                         __METHOD__,
4346                         [
4347                                 'ORDER BY' => "rev_timestamp $sort, rev_id $sort",
4348                                 'IGNORE INDEX' => 'rev_timestamp', // Probably needed for T159319
4349                         ]
4350                 );
4351
4352                 if ( $revId === false ) {
4353                         return false;
4354                 } else {
4355                         return intval( $revId );
4356                 }
4357         }
4358
4359         /**
4360          * Get the revision ID of the previous revision
4361          *
4362          * @param int $revId Revision ID. Get the revision that was before this one.
4363          * @param int $flags Title::GAID_FOR_UPDATE
4364          * @return int|bool Old revision ID, or false if none exists
4365          */
4366         public function getPreviousRevisionID( $revId, $flags = 0 ) {
4367                 return $this->getRelativeRevisionID( $revId, $flags, 'prev' );
4368         }
4369
4370         /**
4371          * Get the revision ID of the next revision
4372          *
4373          * @param int $revId Revision ID. Get the revision that was after this one.
4374          * @param int $flags Title::GAID_FOR_UPDATE
4375          * @return int|bool Next revision ID, or false if none exists
4376          */
4377         public function getNextRevisionID( $revId, $flags = 0 ) {
4378                 return $this->getRelativeRevisionID( $revId, $flags, 'next' );
4379         }
4380
4381         /**
4382          * Get the first revision of the page
4383          *
4384          * @param int $flags Title::GAID_FOR_UPDATE
4385          * @return Revision|null If page doesn't exist
4386          */
4387         public function getFirstRevision( $flags = 0 ) {
4388                 $pageId = $this->getArticleID( $flags );
4389                 if ( $pageId ) {
4390                         $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_REPLICA );
4391                         $revQuery = Revision::getQueryInfo();
4392                         $row = $db->selectRow( $revQuery['tables'], $revQuery['fields'],
4393                                 [ 'rev_page' => $pageId ],
4394                                 __METHOD__,
4395                                 [
4396                                         'ORDER BY' => 'rev_timestamp ASC, rev_id ASC',
4397                                         'IGNORE INDEX' => [ 'revision' => 'rev_timestamp' ], // See T159319
4398                                 ],
4399                                 $revQuery['joins']
4400                         );
4401                         if ( $row ) {
4402                                 return new Revision( $row, 0, $this );
4403                         }
4404                 }
4405                 return null;
4406         }
4407
4408         /**
4409          * Get the oldest revision timestamp of this page
4410          *
4411          * @param int $flags Title::GAID_FOR_UPDATE
4412          * @return string|null MW timestamp
4413          */
4414         public function getEarliestRevTime( $flags = 0 ) {
4415                 $rev = $this->getFirstRevision( $flags );
4416                 return $rev ? $rev->getTimestamp() : null;
4417         }
4418
4419         /**
4420          * Check if this is a new page
4421          *
4422          * @return bool
4423          */
4424         public function isNewPage() {
4425                 $dbr = wfGetDB( DB_REPLICA );
4426                 return (bool)$dbr->selectField( 'page', 'page_is_new', $this->pageCond(), __METHOD__ );
4427         }
4428
4429         /**
4430          * Check whether the number of revisions of this page surpasses $wgDeleteRevisionsLimit
4431          *
4432          * @return bool
4433          */
4434         public function isBigDeletion() {
4435                 global $wgDeleteRevisionsLimit;
4436
4437                 if ( !$wgDeleteRevisionsLimit ) {
4438                         return false;
4439                 }
4440
4441                 if ( $this->mIsBigDeletion === null ) {
4442                         $dbr = wfGetDB( DB_REPLICA );
4443
4444                         $revCount = $dbr->selectRowCount(
4445                                 'revision',
4446                                 '1',
4447                                 [ 'rev_page' => $this->getArticleID() ],
4448                                 __METHOD__,
4449                                 [ 'LIMIT' => $wgDeleteRevisionsLimit + 1 ]
4450                         );
4451
4452                         $this->mIsBigDeletion = $revCount > $wgDeleteRevisionsLimit;
4453                 }
4454
4455                 return $this->mIsBigDeletion;
4456         }
4457
4458         /**
4459          * Get the approximate revision count of this page.
4460          *
4461          * @return int
4462          */
4463         public function estimateRevisionCount() {
4464                 if ( !$this->exists() ) {
4465                         return 0;
4466                 }
4467
4468                 if ( $this->mEstimateRevisions === null ) {
4469                         $dbr = wfGetDB( DB_REPLICA );
4470                         $this->mEstimateRevisions = $dbr->estimateRowCount( 'revision', '*',
4471                                 [ 'rev_page' => $this->getArticleID() ], __METHOD__ );
4472                 }
4473
4474                 return $this->mEstimateRevisions;
4475         }
4476
4477         /**
4478          * Get the number of revisions between the given revision.
4479          * Used for diffs and other things that really need it.
4480          *
4481          * @param int|Revision $old Old revision or rev ID (first before range)
4482          * @param int|Revision $new New revision or rev ID (first after range)
4483          * @param int|null $max Limit of Revisions to count, will be incremented to detect truncations
4484          * @return int Number of revisions between these revisions.
4485          */
4486         public function countRevisionsBetween( $old, $new, $max = null ) {
4487                 if ( !( $old instanceof Revision ) ) {
4488                         $old = Revision::newFromTitle( $this, (int)$old );
4489                 }
4490                 if ( !( $new instanceof Revision ) ) {
4491                         $new = Revision::newFromTitle( $this, (int)$new );
4492                 }
4493                 if ( !$old || !$new ) {
4494                         return 0; // nothing to compare
4495                 }
4496                 $dbr = wfGetDB( DB_REPLICA );
4497                 $conds = [
4498                         'rev_page' => $this->getArticleID(),
4499                         'rev_timestamp > ' . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4500                         'rev_timestamp < ' . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4501                 ];
4502                 if ( $max !== null ) {
4503                         return $dbr->selectRowCount( 'revision', '1',
4504                                 $conds,
4505                                 __METHOD__,
4506                                 [ 'LIMIT' => $max + 1 ] // extra to detect truncation
4507                         );
4508                 } else {
4509                         return (int)$dbr->selectField( 'revision', 'count(*)', $conds, __METHOD__ );
4510                 }
4511         }
4512
4513         /**
4514          * Get the authors between the given revisions or revision IDs.
4515          * Used for diffs and other things that really need it.
4516          *
4517          * @since 1.23
4518          *
4519          * @param int|Revision $old Old revision or rev ID (first before range by default)
4520          * @param int|Revision $new New revision or rev ID (first after range by default)
4521          * @param int $limit Maximum number of authors
4522          * @param string|array $options (Optional): Single option, or an array of options:
4523          *     'include_old' Include $old in the range; $new is excluded.
4524          *     'include_new' Include $new in the range; $old is excluded.
4525          *     'include_both' Include both $old and $new in the range.
4526          *     Unknown option values are ignored.
4527          * @return array|null Names of revision authors in the range; null if not both revisions exist
4528          */
4529         public function getAuthorsBetween( $old, $new, $limit, $options = [] ) {
4530                 if ( !( $old instanceof Revision ) ) {
4531                         $old = Revision::newFromTitle( $this, (int)$old );
4532                 }
4533                 if ( !( $new instanceof Revision ) ) {
4534                         $new = Revision::newFromTitle( $this, (int)$new );
4535                 }
4536                 // XXX: what if Revision objects are passed in, but they don't refer to this title?
4537                 // Add $old->getPage() != $new->getPage() || $old->getPage() != $this->getArticleID()
4538                 // in the sanity check below?
4539                 if ( !$old || !$new ) {
4540                         return null; // nothing to compare
4541                 }
4542                 $authors = [];
4543                 $old_cmp = '>';
4544                 $new_cmp = '<';
4545                 $options = (array)$options;
4546                 if ( in_array( 'include_old', $options ) ) {
4547                         $old_cmp = '>=';
4548                 }
4549                 if ( in_array( 'include_new', $options ) ) {
4550                         $new_cmp = '<=';
4551                 }
4552                 if ( in_array( 'include_both', $options ) ) {
4553                         $old_cmp = '>=';
4554                         $new_cmp = '<=';
4555                 }
4556                 // No DB query needed if $old and $new are the same or successive revisions:
4557                 if ( $old->getId() === $new->getId() ) {
4558                         return ( $old_cmp === '>' && $new_cmp === '<' ) ?
4559                                 [] :
4560                                 [ $old->getUserText( Revision::RAW ) ];
4561                 } elseif ( $old->getId() === $new->getParentId() ) {
4562                         if ( $old_cmp === '>=' && $new_cmp === '<=' ) {
4563                                 $authors[] = $old->getUserText( Revision::RAW );
4564                                 if ( $old->getUserText( Revision::RAW ) != $new->getUserText( Revision::RAW ) ) {
4565                                         $authors[] = $new->getUserText( Revision::RAW );
4566                                 }
4567                         } elseif ( $old_cmp === '>=' ) {
4568                                 $authors[] = $old->getUserText( Revision::RAW );
4569                         } elseif ( $new_cmp === '<=' ) {
4570                                 $authors[] = $new->getUserText( Revision::RAW );
4571                         }
4572                         return $authors;
4573                 }
4574                 $dbr = wfGetDB( DB_REPLICA );
4575                 $revQuery = Revision::getQueryInfo();
4576                 $authors = $dbr->selectFieldValues(
4577                         $revQuery['tables'],
4578                         $revQuery['fields']['rev_user_text'],
4579                         [
4580                                 'rev_page' => $this->getArticleID(),
4581                                 "rev_timestamp $old_cmp " . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4582                                 "rev_timestamp $new_cmp " . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4583                         ], __METHOD__,
4584                         [ 'DISTINCT', 'LIMIT' => $limit + 1 ], // add one so caller knows it was truncated
4585                         $revQuery['joins']
4586                 );
4587                 return $authors;
4588         }
4589
4590         /**
4591          * Get the number of authors between the given revisions or revision IDs.
4592          * Used for diffs and other things that really need it.
4593          *
4594          * @param int|Revision $old Old revision or rev ID (first before range by default)
4595          * @param int|Revision $new New revision or rev ID (first after range by default)
4596          * @param int $limit Maximum number of authors
4597          * @param string|array $options (Optional): Single option, or an array of options:
4598          *     'include_old' Include $old in the range; $new is excluded.
4599          *     'include_new' Include $new in the range; $old is excluded.
4600          *     'include_both' Include both $old and $new in the range.
4601          *     Unknown option values are ignored.
4602          * @return int Number of revision authors in the range; zero if not both revisions exist
4603          */
4604         public function countAuthorsBetween( $old, $new, $limit, $options = [] ) {
4605                 $authors = $this->getAuthorsBetween( $old, $new, $limit, $options );
4606                 return $authors ? count( $authors ) : 0;
4607         }
4608
4609         /**
4610          * Compare with another title.
4611          *
4612          * @param Title $title
4613          * @return bool
4614          */
4615         public function equals( Title $title ) {
4616                 // Note: === is necessary for proper matching of number-like titles.
4617                 return $this->mInterwiki === $title->mInterwiki
4618                         && $this->mNamespace == $title->mNamespace
4619                         && $this->mDbkeyform === $title->mDbkeyform;
4620         }
4621
4622         /**
4623          * Check if this title is a subpage of another title
4624          *
4625          * @param Title $title
4626          * @return bool
4627          */
4628         public function isSubpageOf( Title $title ) {
4629                 return $this->mInterwiki === $title->mInterwiki
4630                         && $this->mNamespace == $title->mNamespace
4631                         && strpos( $this->mDbkeyform, $title->mDbkeyform . '/' ) === 0;
4632         }
4633
4634         /**
4635          * Check if page exists.  For historical reasons, this function simply
4636          * checks for the existence of the title in the page table, and will
4637          * thus return false for interwiki links, special pages and the like.
4638          * If you want to know if a title can be meaningfully viewed, you should
4639          * probably call the isKnown() method instead.
4640          *
4641          * @param int $flags An optional bit field; may be Title::GAID_FOR_UPDATE to check
4642          *   from master/for update
4643          * @return bool
4644          */
4645         public function exists( $flags = 0 ) {
4646                 $exists = $this->getArticleID( $flags ) != 0;
4647                 Hooks::run( 'TitleExists', [ $this, &$exists ] );
4648                 return $exists;
4649         }
4650
4651         /**
4652          * Should links to this title be shown as potentially viewable (i.e. as
4653          * "bluelinks"), even if there's no record by this title in the page
4654          * table?
4655          *
4656          * This function is semi-deprecated for public use, as well as somewhat
4657          * misleadingly named.  You probably just want to call isKnown(), which
4658          * calls this function internally.
4659          *
4660          * (ISSUE: Most of these checks are cheap, but the file existence check
4661          * can potentially be quite expensive.  Including it here fixes a lot of
4662          * existing code, but we might want to add an optional parameter to skip
4663          * it and any other expensive checks.)
4664          *
4665          * @return bool
4666          */
4667         public function isAlwaysKnown() {
4668                 $isKnown = null;
4669
4670                 /**
4671                  * Allows overriding default behavior for determining if a page exists.
4672                  * If $isKnown is kept as null, regular checks happen. If it's
4673                  * a boolean, this value is returned by the isKnown method.
4674                  *
4675                  * @since 1.20
4676                  *
4677                  * @param Title $title
4678                  * @param bool|null $isKnown
4679                  */
4680                 Hooks::run( 'TitleIsAlwaysKnown', [ $this, &$isKnown ] );
4681
4682                 if ( !is_null( $isKnown ) ) {
4683                         return $isKnown;
4684                 }
4685
4686                 if ( $this->isExternal() ) {
4687                         return true; // any interwiki link might be viewable, for all we know
4688                 }
4689
4690                 switch ( $this->mNamespace ) {
4691                         case NS_MEDIA:
4692                         case NS_FILE:
4693                                 // file exists, possibly in a foreign repo
4694                                 return (bool)wfFindFile( $this );
4695                         case NS_SPECIAL:
4696                                 // valid special page
4697                                 return MediaWikiServices::getInstance()->getSpecialPageFactory()->
4698                                         exists( $this->mDbkeyform );
4699                         case NS_MAIN:
4700                                 // selflink, possibly with fragment
4701                                 return $this->mDbkeyform == '';
4702                         case NS_MEDIAWIKI:
4703                                 // known system message
4704                                 return $this->hasSourceText() !== false;
4705                         default:
4706                                 return false;
4707                 }
4708         }
4709
4710         /**
4711          * Does this title refer to a page that can (or might) be meaningfully
4712          * viewed?  In particular, this function may be used to determine if
4713          * links to the title should be rendered as "bluelinks" (as opposed to
4714          * "redlinks" to non-existent pages).
4715          * Adding something else to this function will cause inconsistency
4716          * since LinkHolderArray calls isAlwaysKnown() and does its own
4717          * page existence check.
4718          *
4719          * @return bool
4720          */
4721         public function isKnown() {
4722                 return $this->isAlwaysKnown() || $this->exists();
4723         }
4724
4725         /**
4726          * Does this page have source text?
4727          *
4728          * @return bool
4729          */
4730         public function hasSourceText() {
4731                 if ( $this->exists() ) {
4732                         return true;
4733                 }
4734
4735                 if ( $this->mNamespace == NS_MEDIAWIKI ) {
4736                         // If the page doesn't exist but is a known system message, default
4737                         // message content will be displayed, same for language subpages-
4738                         // Use always content language to avoid loading hundreds of languages
4739                         // to get the link color.
4740                         $contLang = MediaWikiServices::getInstance()->getContentLanguage();
4741                         list( $name, ) = MessageCache::singleton()->figureMessage(
4742                                 $contLang->lcfirst( $this->getText() )
4743                         );
4744                         $message = wfMessage( $name )->inLanguage( $contLang )->useDatabase( false );
4745                         return $message->exists();
4746                 }
4747
4748                 return false;
4749         }
4750
4751         /**
4752          * Get the default (plain) message contents for an page that overrides an
4753          * interface message key.
4754          *
4755          * Primary use cases:
4756          *
4757          * - Article:
4758          *    - Show default when viewing the page. The Article::getSubstituteContent
4759          *      method displays the default message content, instead of the
4760          *      'noarticletext' placeholder message normally used.
4761          *
4762          * - EditPage:
4763          *    - Title of edit page. When creating an interface message override,
4764          *      the editor is told they are "Editing the page", instead of
4765          *      "Creating the page". (EditPage::setHeaders)
4766          *    - Edit notice. The 'translateinterface' edit notice is shown when creating
4767          *      or editing a an interface message override. (EditPage::showIntro)
4768          *    - Opening the editor. The contents of the localisation message are used
4769          *      as contents of the editor when creating a new page in the MediaWiki
4770          *      namespace. This simplifies the process for editors when "changing"
4771          *      an interface message by creating an override. (EditPage::getContentObject)
4772          *    - Showing a diff. The left-hand side of a diff when an editor is
4773          *      previewing their changes before saving the creation of a page in the
4774          *      MediaWiki namespace. (EditPage::showDiff)
4775          *    - Disallowing a save. When attempting to create a a MediaWiki-namespace
4776          *      page with the proposed content matching the interface message default,
4777          *      the save is rejected, the same way we disallow blank pages from being
4778          *      created. (EditPage::internalAttemptSave)
4779          *
4780          * - ApiEditPage:
4781          *    - Default content, when using the 'prepend' or 'append' feature.
4782          *
4783          * - SkinTemplate:
4784          *    - Label the create action as "Edit", if the page can be an override.
4785          *
4786          * @return string|bool
4787          */
4788         public function getDefaultMessageText() {
4789                 if ( $this->mNamespace != NS_MEDIAWIKI ) { // Just in case
4790                         return false;
4791                 }
4792
4793                 list( $name, $lang ) = MessageCache::singleton()->figureMessage(
4794                         MediaWikiServices::getInstance()->getContentLanguage()->lcfirst( $this->getText() )
4795                 );
4796                 $message = wfMessage( $name )->inLanguage( $lang )->useDatabase( false );
4797
4798                 if ( $message->exists() ) {
4799                         return $message->plain();
4800                 } else {
4801                         return false;
4802                 }
4803         }
4804
4805         /**
4806          * Updates page_touched for this page; called from LinksUpdate.php
4807          *
4808          * @param string|null $purgeTime [optional] TS_MW timestamp
4809          * @return bool True if the update succeeded
4810          */
4811         public function invalidateCache( $purgeTime = null ) {
4812                 if ( wfReadOnly() ) {
4813                         return false;
4814                 } elseif ( $this->mArticleID === 0 ) {
4815                         return true; // avoid gap locking if we know it's not there
4816                 }
4817
4818                 $dbw = wfGetDB( DB_MASTER );
4819                 $dbw->onTransactionPreCommitOrIdle(
4820                         function () use ( $dbw ) {
4821                                 ResourceLoaderWikiModule::invalidateModuleCache(
4822                                         $this, null, null, $dbw->getDomainId() );
4823                         },
4824                         __METHOD__
4825                 );
4826
4827                 $conds = $this->pageCond();
4828                 DeferredUpdates::addUpdate(
4829                         new AutoCommitUpdate(
4830                                 $dbw,
4831                                 __METHOD__,
4832                                 function ( IDatabase $dbw, $fname ) use ( $conds, $purgeTime ) {
4833                                         $dbTimestamp = $dbw->timestamp( $purgeTime ?: time() );
4834                                         $dbw->update(
4835                                                 'page',
4836                                                 [ 'page_touched' => $dbTimestamp ],
4837                                                 $conds + [ 'page_touched < ' . $dbw->addQuotes( $dbTimestamp ) ],
4838                                                 $fname
4839                                         );
4840                                         MediaWikiServices::getInstance()->getLinkCache()->invalidateTitle( $this );
4841                                 }
4842                         ),
4843                         DeferredUpdates::PRESEND
4844                 );
4845
4846                 return true;
4847         }
4848
4849         /**
4850          * Update page_touched timestamps and send CDN purge messages for
4851          * pages linking to this title. May be sent to the job queue depending
4852          * on the number of links. Typically called on create and delete.
4853          */
4854         public function touchLinks() {
4855                 DeferredUpdates::addUpdate( new HTMLCacheUpdate( $this, 'pagelinks', 'page-touch' ) );
4856                 if ( $this->mNamespace == NS_CATEGORY ) {
4857                         DeferredUpdates::addUpdate(
4858                                 new HTMLCacheUpdate( $this, 'categorylinks', 'category-touch' )
4859                         );
4860                 }
4861         }
4862
4863         /**
4864          * Get the last touched timestamp
4865          *
4866          * @param IDatabase|null $db
4867          * @return string|false Last-touched timestamp
4868          */
4869         public function getTouched( $db = null ) {
4870                 if ( $db === null ) {
4871                         $db = wfGetDB( DB_REPLICA );
4872                 }
4873                 $touched = $db->selectField( 'page', 'page_touched', $this->pageCond(), __METHOD__ );
4874                 return $touched;
4875         }
4876
4877         /**
4878          * Get the timestamp when this page was updated since the user last saw it.
4879          *
4880          * @param User|null $user
4881          * @return string|null
4882          */
4883         public function getNotificationTimestamp( $user = null ) {
4884                 global $wgUser;
4885
4886                 // Assume current user if none given
4887                 if ( !$user ) {
4888                         $user = $wgUser;
4889                 }
4890                 // Check cache first
4891                 $uid = $user->getId();
4892                 if ( !$uid ) {
4893                         return false;
4894                 }
4895                 // avoid isset here, as it'll return false for null entries
4896                 if ( array_key_exists( $uid, $this->mNotificationTimestamp ) ) {
4897                         return $this->mNotificationTimestamp[$uid];
4898                 }
4899                 // Don't cache too much!
4900                 if ( count( $this->mNotificationTimestamp ) >= self::CACHE_MAX ) {
4901                         $this->mNotificationTimestamp = [];
4902                 }
4903
4904                 $store = MediaWikiServices::getInstance()->getWatchedItemStore();
4905                 $watchedItem = $store->getWatchedItem( $user, $this );
4906                 if ( $watchedItem ) {
4907                         $this->mNotificationTimestamp[$uid] = $watchedItem->getNotificationTimestamp();
4908                 } else {
4909                         $this->mNotificationTimestamp[$uid] = false;
4910                 }
4911
4912                 return $this->mNotificationTimestamp[$uid];
4913         }
4914
4915         /**
4916          * Generate strings used for xml 'id' names in monobook tabs
4917          *
4918          * @param string $prepend Defaults to 'nstab-'
4919          * @return string XML 'id' name
4920          */
4921         public function getNamespaceKey( $prepend = 'nstab-' ) {
4922                 // Gets the subject namespace of this title
4923                 $subjectNS = MWNamespace::getSubject( $this->mNamespace );
4924                 // Prefer canonical namespace name for HTML IDs
4925                 $namespaceKey = MWNamespace::getCanonicalName( $subjectNS );
4926                 if ( $namespaceKey === false ) {
4927                         // Fallback to localised text
4928                         $namespaceKey = $this->getSubjectNsText();
4929                 }
4930                 // Makes namespace key lowercase
4931                 $namespaceKey = MediaWikiServices::getInstance()->getContentLanguage()->lc( $namespaceKey );
4932                 // Uses main
4933                 if ( $namespaceKey == '' ) {
4934                         $namespaceKey = 'main';
4935                 }
4936                 // Changes file to image for backwards compatibility
4937                 if ( $namespaceKey == 'file' ) {
4938                         $namespaceKey = 'image';
4939                 }
4940                 return $prepend . $namespaceKey;
4941         }
4942
4943         /**
4944          * Get all extant redirects to this Title
4945          *
4946          * @param int|null $ns Single namespace to consider; null to consider all namespaces
4947          * @return Title[] Array of Title redirects to this title
4948          */
4949         public function getRedirectsHere( $ns = null ) {
4950                 $redirs = [];
4951
4952                 $dbr = wfGetDB( DB_REPLICA );
4953                 $where = [
4954                         'rd_namespace' => $this->mNamespace,
4955                         'rd_title' => $this->mDbkeyform,
4956                         'rd_from = page_id'
4957                 ];
4958                 if ( $this->isExternal() ) {
4959                         $where['rd_interwiki'] = $this->mInterwiki;
4960                 } else {
4961                         $where[] = 'rd_interwiki = ' . $dbr->addQuotes( '' ) . ' OR rd_interwiki IS NULL';
4962                 }
4963                 if ( !is_null( $ns ) ) {
4964                         $where['page_namespace'] = $ns;
4965                 }
4966
4967                 $res = $dbr->select(
4968                         [ 'redirect', 'page' ],
4969                         [ 'page_namespace', 'page_title' ],
4970                         $where,
4971                         __METHOD__
4972                 );
4973
4974                 foreach ( $res as $row ) {
4975                         $redirs[] = self::newFromRow( $row );
4976                 }
4977                 return $redirs;
4978         }
4979
4980         /**
4981          * Check if this Title is a valid redirect target
4982          *
4983          * @return bool
4984          */
4985         public function isValidRedirectTarget() {
4986                 global $wgInvalidRedirectTargets;
4987
4988                 if ( $this->isSpecialPage() ) {
4989                         // invalid redirect targets are stored in a global array, but explicitly disallow Userlogout here
4990                         if ( $this->isSpecial( 'Userlogout' ) ) {
4991                                 return false;
4992                         }
4993
4994                         foreach ( $wgInvalidRedirectTargets as $target ) {
4995                                 if ( $this->isSpecial( $target ) ) {
4996                                         return false;
4997                                 }
4998                         }
4999                 }
5000
5001                 return true;
5002         }
5003
5004         /**
5005          * Get a backlink cache object
5006          *
5007          * @return BacklinkCache
5008          */
5009         public function getBacklinkCache() {
5010                 return BacklinkCache::get( $this );
5011         }
5012
5013         /**
5014          * Whether the magic words __INDEX__ and __NOINDEX__ function for this page.
5015          *
5016          * @return bool
5017          */
5018         public function canUseNoindex() {
5019                 global $wgExemptFromUserRobotsControl;
5020
5021                 $bannedNamespaces = is_null( $wgExemptFromUserRobotsControl )
5022                         ? MWNamespace::getContentNamespaces()
5023                         : $wgExemptFromUserRobotsControl;
5024
5025                 return !in_array( $this->mNamespace, $bannedNamespaces );
5026         }
5027
5028         /**
5029          * Returns the raw sort key to be used for categories, with the specified
5030          * prefix.  This will be fed to Collation::getSortKey() to get a
5031          * binary sortkey that can be used for actual sorting.
5032          *
5033          * @param string $prefix The prefix to be used, specified using
5034          *   {{defaultsort:}} or like [[Category:Foo|prefix]].  Empty for no
5035          *   prefix.
5036          * @return string
5037          */
5038         public function getCategorySortkey( $prefix = '' ) {
5039                 $unprefixed = $this->getText();
5040
5041                 // Anything that uses this hook should only depend
5042                 // on the Title object passed in, and should probably
5043                 // tell the users to run updateCollations.php --force
5044                 // in order to re-sort existing category relations.
5045                 Hooks::run( 'GetDefaultSortkey', [ $this, &$unprefixed ] );
5046                 if ( $prefix !== '' ) {
5047                         # Separate with a line feed, so the unprefixed part is only used as
5048                         # a tiebreaker when two pages have the exact same prefix.
5049                         # In UCA, tab is the only character that can sort above LF
5050                         # so we strip both of them from the original prefix.
5051                         $prefix = strtr( $prefix, "\n\t", '  ' );
5052                         return "$prefix\n$unprefixed";
5053                 }
5054                 return $unprefixed;
5055         }
5056
5057         /**
5058          * Returns the page language code saved in the database, if $wgPageLanguageUseDB is set
5059          * to true in LocalSettings.php, otherwise returns false. If there is no language saved in
5060          * the db, it will return NULL.
5061          *
5062          * @return string|null|bool
5063          */
5064         private function getDbPageLanguageCode() {
5065                 global $wgPageLanguageUseDB;
5066
5067                 // check, if the page language could be saved in the database, and if so and
5068                 // the value is not requested already, lookup the page language using LinkCache
5069                 if ( $wgPageLanguageUseDB && $this->mDbPageLanguage === false ) {
5070                         $linkCache = MediaWikiServices::getInstance()->getLinkCache();
5071                         $linkCache->addLinkObj( $this );
5072                         $this->mDbPageLanguage = $linkCache->getGoodLinkFieldObj( $this, 'lang' );
5073                 }
5074
5075                 return $this->mDbPageLanguage;
5076         }
5077
5078         /**
5079          * Get the language in which the content of this page is written in
5080          * wikitext. Defaults to content language, but in certain cases it can be
5081          * e.g. $wgLang (such as special pages, which are in the user language).
5082          *
5083          * @since 1.18
5084          * @return Language
5085          */
5086         public function getPageLanguage() {
5087                 global $wgLang, $wgLanguageCode;
5088                 if ( $this->isSpecialPage() ) {
5089                         // special pages are in the user language
5090                         return $wgLang;
5091                 }
5092
5093                 // Checking if DB language is set
5094                 $dbPageLanguage = $this->getDbPageLanguageCode();
5095                 if ( $dbPageLanguage ) {
5096                         return wfGetLangObj( $dbPageLanguage );
5097                 }
5098
5099                 if ( !$this->mPageLanguage || $this->mPageLanguage[1] !== $wgLanguageCode ) {
5100                         // Note that this may depend on user settings, so the cache should
5101                         // be only per-request.
5102                         // NOTE: ContentHandler::getPageLanguage() may need to load the
5103                         // content to determine the page language!
5104                         // Checking $wgLanguageCode hasn't changed for the benefit of unit
5105                         // tests.
5106                         $contentHandler = ContentHandler::getForTitle( $this );
5107                         $langObj = $contentHandler->getPageLanguage( $this );
5108                         $this->mPageLanguage = [ $langObj->getCode(), $wgLanguageCode ];
5109                 } else {
5110                         $langObj = Language::factory( $this->mPageLanguage[0] );
5111                 }
5112
5113                 return $langObj;
5114         }
5115
5116         /**
5117          * Get the language in which the content of this page is written when
5118          * viewed by user. Defaults to content language, but in certain cases it can be
5119          * e.g. $wgLang (such as special pages, which are in the user language).
5120          *
5121          * @since 1.20
5122          * @return Language
5123          */
5124         public function getPageViewLanguage() {
5125                 global $wgLang;
5126
5127                 if ( $this->isSpecialPage() ) {
5128                         // If the user chooses a variant, the content is actually
5129                         // in a language whose code is the variant code.
5130                         $variant = $wgLang->getPreferredVariant();
5131                         if ( $wgLang->getCode() !== $variant ) {
5132                                 return Language::factory( $variant );
5133                         }
5134
5135                         return $wgLang;
5136                 }
5137
5138                 // Checking if DB language is set
5139                 $dbPageLanguage = $this->getDbPageLanguageCode();
5140                 if ( $dbPageLanguage ) {
5141                         $pageLang = wfGetLangObj( $dbPageLanguage );
5142                         $variant = $pageLang->getPreferredVariant();
5143                         if ( $pageLang->getCode() !== $variant ) {
5144                                 $pageLang = Language::factory( $variant );
5145                         }
5146
5147                         return $pageLang;
5148                 }
5149
5150                 // @note Can't be cached persistently, depends on user settings.
5151                 // @note ContentHandler::getPageViewLanguage() may need to load the
5152                 //   content to determine the page language!
5153                 $contentHandler = ContentHandler::getForTitle( $this );
5154                 $pageLang = $contentHandler->getPageViewLanguage( $this );
5155                 return $pageLang;
5156         }
5157
5158         /**
5159          * Get a list of rendered edit notices for this page.
5160          *
5161          * Array is keyed by the original message key, and values are rendered using parseAsBlock, so
5162          * they will already be wrapped in paragraphs.
5163          *
5164          * @since 1.21
5165          * @param int $oldid Revision ID that's being edited
5166          * @return array
5167          */
5168         public function getEditNotices( $oldid = 0 ) {
5169                 $notices = [];
5170
5171                 // Optional notice for the entire namespace
5172                 $editnotice_ns = 'editnotice-' . $this->mNamespace;
5173                 $msg = wfMessage( $editnotice_ns );
5174                 if ( $msg->exists() ) {
5175                         $html = $msg->parseAsBlock();
5176                         // Edit notices may have complex logic, but output nothing (T91715)
5177                         if ( trim( $html ) !== '' ) {
5178                                 $notices[$editnotice_ns] = Html::rawElement(
5179                                         'div',
5180                                         [ 'class' => [
5181                                                 'mw-editnotice',
5182                                                 'mw-editnotice-namespace',
5183                                                 Sanitizer::escapeClass( "mw-$editnotice_ns" )
5184                                         ] ],
5185                                         $html
5186                                 );
5187                         }
5188                 }
5189
5190                 if ( MWNamespace::hasSubpages( $this->mNamespace ) ) {
5191                         // Optional notice for page itself and any parent page
5192                         $editnotice_base = $editnotice_ns;
5193                         foreach ( explode( '/', $this->mDbkeyform ) as $part ) {
5194                                 $editnotice_base .= '-' . $part;
5195                                 $msg = wfMessage( $editnotice_base );
5196                                 if ( $msg->exists() ) {
5197                                         $html = $msg->parseAsBlock();
5198                                         if ( trim( $html ) !== '' ) {
5199                                                 $notices[$editnotice_base] = Html::rawElement(
5200                                                         'div',
5201                                                         [ 'class' => [
5202                                                                 'mw-editnotice',
5203                                                                 'mw-editnotice-base',
5204                                                                 Sanitizer::escapeClass( "mw-$editnotice_base" )
5205                                                         ] ],
5206                                                         $html
5207                                                 );
5208                                         }
5209                                 }
5210                         }
5211                 } else {
5212                         // Even if there are no subpages in namespace, we still don't want "/" in MediaWiki message keys
5213                         $editnoticeText = $editnotice_ns . '-' . strtr( $this->mDbkeyform, '/', '-' );
5214                         $msg = wfMessage( $editnoticeText );
5215                         if ( $msg->exists() ) {
5216                                 $html = $msg->parseAsBlock();
5217                                 if ( trim( $html ) !== '' ) {
5218                                         $notices[$editnoticeText] = Html::rawElement(
5219                                                 'div',
5220                                                 [ 'class' => [
5221                                                         'mw-editnotice',
5222                                                         'mw-editnotice-page',
5223                                                         Sanitizer::escapeClass( "mw-$editnoticeText" )
5224                                                 ] ],
5225                                                 $html
5226                                         );
5227                                 }
5228                         }
5229                 }
5230
5231                 Hooks::run( 'TitleGetEditNotices', [ $this, $oldid, &$notices ] );
5232                 return $notices;
5233         }
5234
5235         /**
5236          * @return array
5237          */
5238         public function __sleep() {
5239                 return [
5240                         'mNamespace',
5241                         'mDbkeyform',
5242                         'mFragment',
5243                         'mInterwiki',
5244                         'mLocalInterwiki',
5245                         'mUserCaseDBKey',
5246                         'mDefaultNamespace',
5247                 ];
5248         }
5249
5250         public function __wakeup() {
5251                 $this->mArticleID = ( $this->mNamespace >= 0 ) ? -1 : 0;
5252                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
5253                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
5254         }
5255
5256 }