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|null */
  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|null
 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|null A corresponding TitleValue object */
 177         private $mTitleValue = null;
 178
 179         /** @var bool|null 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 self();
 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 ( $text === null ) {
 286                         return null;
 287                 }
 288
 289                 try {
 290                         return self::newFromTextThrow( (string)$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                 $t->mDefaultNamespace = (int)$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
 441                 return $title;
 442         }
 443
 444         /**
 445          * Make an array of titles from an array of IDs
 446          *
 447          * @param int[] $ids Array of IDs
 448          * @return Title[] Array of Titles
 449          */
 450         public static function newFromIDs( $ids ) {
 451                 if ( !count( $ids ) ) {
 452                         return [];
 453                 }
 454                 $dbr = wfGetDB( DB_REPLICA );
 455
 456                 $res = $dbr->select(
 457                         'page',
 458                         self::getSelectFields(),
 459                         [ 'page_id' => $ids ],
 460                         __METHOD__
 461                 );
 462
 463                 $titles = [];
 464                 foreach ( $res as $row ) {
 465                         $titles[] = self::newFromRow( $row );
 466                 }
 467                 return $titles;
 468         }
 469
 470         /**
 471          * Make a Title object from a DB row
 472          *
 473          * @param stdClass $row Object database row (needs at least page_title,page_namespace)
 474          * @return Title Corresponding Title
 475          */
 476         public static function newFromRow( $row ) {
 477                 $t = self::makeTitle( $row->page_namespace, $row->page_title );
 478                 $t->loadFromRow( $row );
 479                 return $t;
 480         }
 481
 482         /**
 483          * Load Title object fields from a DB row.
 484          * If false is given, the title will be treated as non-existing.
 485          *
 486          * @param stdClass|bool $row Database row
 487          */
 488         public function loadFromRow( $row ) {
 489                 if ( $row ) { // page found
 490                         if ( isset( $row->page_id ) ) {
 491                                 $this->mArticleID = (int)$row->page_id;
 492                         }
 493                         if ( isset( $row->page_len ) ) {
 494                                 $this->mLength = (int)$row->page_len;
 495                         }
 496                         if ( isset( $row->page_is_redirect ) ) {
 497                                 $this->mRedirect = (bool)$row->page_is_redirect;
 498                         }
 499                         if ( isset( $row->page_latest ) ) {
 500                                 $this->mLatestID = (int)$row->page_latest;
 501                         }
 502                         if ( !$this->mForcedContentModel && isset( $row->page_content_model ) ) {
 503                                 $this->mContentModel = (string)$row->page_content_model;
 504                         } elseif ( !$this->mForcedContentModel ) {
 505                                 $this->mContentModel = false; # initialized lazily in getContentModel()
 506                         }
 507                         if ( isset( $row->page_lang ) ) {
 508                                 $this->mDbPageLanguage = (string)$row->page_lang;
 509                         }
 510                         if ( isset( $row->page_restrictions ) ) {
 511                                 $this->mOldRestrictions = $row->page_restrictions;
 512                         }
 513                 } else { // page not found
 514                         $this->mArticleID = 0;
 515                         $this->mLength = 0;
 516                         $this->mRedirect = false;
 517                         $this->mLatestID = 0;
 518                         if ( !$this->mForcedContentModel ) {
 519                                 $this->mContentModel = false; # initialized lazily in getContentModel()
 520                         }
 521                 }
 522         }
 523
 524         /**
 525          * Create a new Title from a namespace index and a DB key.
 526          *
 527          * It's assumed that $ns and $title are safe, for instance when
 528          * they came directly from the database or a special page name,
 529          * not from user input.
 530          *
 531          * No validation is applied. For convenience, spaces are normalized
 532          * to underscores, so that e.g. user_text fields can be used directly.
 533          *
 534          * @note This method may return Title objects that are "invalid"
 535          * according to the isValid() method. This is usually caused by
 536          * configuration changes: e.g. a namespace that was once defined is
 537          * no longer configured, or a character that was once allowed in
 538          * titles is now forbidden.
 539          *
 540          * @param int $ns The namespace of the article
 541          * @param string $title The unprefixed database key form
 542          * @param string $fragment The link fragment (after the "#")
 543          * @param string $interwiki The interwiki prefix
 544          * @return Title The new object
 545          */
 546         public static function makeTitle( $ns, $title, $fragment = '', $interwiki = '' ) {
 547                 $t = new Title();
 548                 $t->mInterwiki = $interwiki;
 549                 $t->mFragment = $fragment;
 550                 $t->mNamespace = $ns = (int)$ns;
 551                 $t->mDbkeyform = strtr( $title, ' ', '_' );
 552                 $t->mArticleID = ( $ns >= 0 ) ? -1 : 0;
 553                 $t->mUrlform = wfUrlencode( $t->mDbkeyform );
 554                 $t->mTextform = strtr( $title, '_', ' ' );
 555                 $t->mContentModel = false; # initialized lazily in getContentModel()
 556                 return $t;
 557         }
 558
 559         /**
 560          * Create a new Title from a namespace index and a DB key.
 561          * The parameters will be checked for validity, which is a bit slower
 562          * than makeTitle() but safer for user-provided data.
 563          *
 564          * Title objects returned by makeTitleSafe() are guaranteed to be valid,
 565          * that is, they return true from the isValid() method. If no valid Title
 566          * can be constructed from the input, this method returns null.
 567          *
 568          * @param int $ns The namespace of the article
 569          * @param string $title Database key form
 570          * @param string $fragment The link fragment (after the "#")
 571          * @param string $interwiki Interwiki prefix
 572          * @return Title|null The new object, or null on an error
 573          */
 574         public static function makeTitleSafe( $ns, $title, $fragment = '', $interwiki = '' ) {
 575                 // NOTE: ideally, this would just call makeTitle() and then isValid(),
 576                 // but presently, that means more overhead on a potential performance hotspot.
 577
 578                 if ( !MWNamespace::exists( $ns ) ) {
 579                         return null;
 580                 }
 581
 582                 $t = new Title();
 583                 $t->mDbkeyform = self::makeName( $ns, $title, $fragment, $interwiki, true );
 584
 585                 try {
 586                         $t->secureAndSplit();
 587                         return $t;
 588                 } catch ( MalformedTitleException $ex ) {
 589                         return null;
 590                 }
 591         }
 592
 593         /**
 594          * Create a new Title for the Main Page
 595          *
 596          * @return Title The new object
 597          */
 598         public static function newMainPage() {
 599                 $title = self::newFromText( wfMessage( 'mainpage' )->inContentLanguage()->text() );
 600                 // Don't give fatal errors if the message is broken
 601                 if ( !$title ) {
 602                         $title = self::newFromText( 'Main Page' );
 603                 }
 604                 return $title;
 605         }
 606
 607         /**
 608          * Get the prefixed DB key associated with an ID
 609          *
 610          * @param int $id The page_id of the article
 611          * @return Title|null An object representing the article, or null if no such article was found
 612          */
 613         public static function nameOf( $id ) {
 614                 $dbr = wfGetDB( DB_REPLICA );
 615
 616                 $s = $dbr->selectRow(
 617                         'page',
 618                         [ 'page_namespace', 'page_title' ],
 619                         [ 'page_id' => $id ],
 620                         __METHOD__
 621                 );
 622                 if ( $s === false ) {
 623                         return null;
 624                 }
 625
 626                 $n = self::makeName( $s->page_namespace, $s->page_title );
 627                 return $n;
 628         }
 629
 630         /**
 631          * Get a regex character class describing the legal characters in a link
 632          *
 633          * @return string The list of characters, not delimited
 634          */
 635         public static function legalChars() {
 636                 global $wgLegalTitleChars;
 637                 return $wgLegalTitleChars;
 638         }
 639
 640         /**
 641          * Utility method for converting a character sequence from bytes to Unicode.
 642          *
 643          * Primary usecase being converting $wgLegalTitleChars to a sequence usable in
 644          * javascript, as PHP uses UTF-8 bytes where javascript uses Unicode code units.
 645          *
 646          * @param string $byteClass
 647          * @return string
 648          */
 649         public static function convertByteClassToUnicodeClass( $byteClass ) {
 650                 $length = strlen( $byteClass );
 651                 // Input token queue
 652                 $x0 = $x1 = $x2 = '';
 653                 // Decoded queue
 654                 $d0 = $d1 = $d2 = '';
 655                 // Decoded integer codepoints
 656                 $ord0 = $ord1 = $ord2 = 0;
 657                 // Re-encoded queue
 658                 $r0 = $r1 = $r2 = '';
 659                 // Output
 660                 $out = '';
 661                 // Flags
 662                 $allowUnicode = false;
 663                 for ( $pos = 0; $pos < $length; $pos++ ) {
 664                         // Shift the queues down
 665                         $x2 = $x1;
 666                         $x1 = $x0;
 667                         $d2 = $d1;
 668                         $d1 = $d0;
 669                         $ord2 = $ord1;
 670                         $ord1 = $ord0;
 671                         $r2 = $r1;
 672                         $r1 = $r0;
 673                         // Load the current input token and decoded values
 674                         $inChar = $byteClass[$pos];
 675                         if ( $inChar == '\\' ) {
 676                                 if ( preg_match( '/x([0-9a-fA-F]{2})/A', $byteClass, $m, 0, $pos + 1 ) ) {
 677                                         $x0 = $inChar . $m[0];
 678                                         $d0 = chr( hexdec( $m[1] ) );
 679                                         $pos += strlen( $m[0] );
 680                                 } elseif ( preg_match( '/[0-7]{3}/A', $byteClass, $m, 0, $pos + 1 ) ) {
 681                                         $x0 = $inChar . $m[0];
 682                                         $d0 = chr( octdec( $m[0] ) );
 683                                         $pos += strlen( $m[0] );
 684                                 } elseif ( $pos + 1 >= $length ) {
 685                                         $x0 = $d0 = '\\';
 686                                 } else {
 687                                         $d0 = $byteClass[$pos + 1];
 688                                         $x0 = $inChar . $d0;
 689                                         $pos += 1;
 690                                 }
 691                         } else {
 692                                 $x0 = $d0 = $inChar;
 693                         }
 694                         $ord0 = ord( $d0 );
 695                         // Load the current re-encoded value
 696                         if ( $ord0 < 32 || $ord0 == 0x7f ) {
 697                                 $r0 = sprintf( '\x%02x', $ord0 );
 698                         } elseif ( $ord0 >= 0x80 ) {
 699                                 // Allow unicode if a single high-bit character appears
 700                                 $r0 = sprintf( '\x%02x', $ord0 );
 701                                 $allowUnicode = true;
 702                         } elseif ( strpos( '-\\[]^', $d0 ) !== false ) {
 703                                 $r0 = '\\' . $d0;
 704                         } else {
 705                                 $r0 = $d0;
 706                         }
 707                         // Do the output
 708                         if ( $x0 !== '' && $x1 === '-' && $x2 !== '' ) {
 709                                 // Range
 710                                 if ( $ord2 > $ord0 ) {
 711                                         // Empty range
 712                                 } elseif ( $ord0 >= 0x80 ) {
 713                                         // Unicode range
 714                                         $allowUnicode = true;
 715                                         if ( $ord2 < 0x80 ) {
 716                                                 // Keep the non-unicode section of the range
 717                                                 $out .= "$r2-\\x7F";
 718                                         }
 719                                 } else {
 720                                         // Normal range
 721                                         $out .= "$r2-$r0";
 722                                 }
 723                                 // Reset state to the initial value
 724                                 $x0 = $x1 = $d0 = $d1 = $r0 = $r1 = '';
 725                         } elseif ( $ord2 < 0x80 ) {
 726                                 // ASCII character
 727                                 $out .= $r2;
 728                         }
 729                 }
 730                 if ( $ord1 < 0x80 ) {
 731                         $out .= $r1;
 732                 }
 733                 if ( $ord0 < 0x80 ) {
 734                         $out .= $r0;
 735                 }
 736                 if ( $allowUnicode ) {
 737                         $out .= '\u0080-\uFFFF';
 738                 }
 739                 return $out;
 740         }
 741
 742         /**
 743          * Make a prefixed DB key from a DB key and a namespace index
 744          *
 745          * @param int $ns Numerical representation of the namespace
 746          * @param string $title The DB key form the title
 747          * @param string $fragment The link fragment (after the "#")
 748          * @param string $interwiki The interwiki prefix
 749          * @param bool $canonicalNamespace If true, use the canonical name for
 750          *   $ns instead of the localized version.
 751          * @return string The prefixed form of the title
 752          */
 753         public static function makeName( $ns, $title, $fragment = '', $interwiki = '',
 754                 $canonicalNamespace = false
 755         ) {
 756                 if ( $canonicalNamespace ) {
 757                         $namespace = MWNamespace::getCanonicalName( $ns );
 758                 } else {
 759                         $namespace = MediaWikiServices::getInstance()->getContentLanguage()->getNsText( $ns );
 760                 }
 761                 $name = $namespace == '' ? $title : "$namespace:$title";
 762                 if ( strval( $interwiki ) != '' ) {
 763                         $name = "$interwiki:$name";
 764                 }
 765                 if ( strval( $fragment ) != '' ) {
 766                         $name .= '#' . $fragment;
 767                 }
 768                 return $name;
 769         }
 770
 771         /**
 772          * Callback for usort() to do title sorts by (namespace, title)
 773          *
 774          * @param LinkTarget $a
 775          * @param LinkTarget $b
 776          *
 777          * @return int Result of string comparison, or namespace comparison
 778          */
 779         public static function compare( LinkTarget $a, LinkTarget $b ) {
 780                 return $a->getNamespace() <=> $b->getNamespace()
 781                         ?: strcmp( $a->getText(), $b->getText() );
 782         }
 783
 784         /**
 785          * Returns true if the title is valid, false if it is invalid.
 786          *
 787          * Valid titles can be round-tripped via makeTitleSafe() and newFromText().
 788          * Invalid titles may get returned from makeTitle(), and it may be useful to
 789          * allow them to exist, e.g. in order to process log entries about pages in
 790          * namespaces that belong to extensions that are no longer installed.
 791          *
 792          * @note This method is relatively expensive. When constructing Title
 793          * objects that need to be valid, use an instantiator method that is guaranteed
 794          * to return valid titles, such as makeTitleSafe() or newFromText().
 795          *
 796          * @return bool
 797          */
 798         public function isValid() {
 799                 if ( !MWNamespace::exists( $this->mNamespace ) ) {
 800                         return false;
 801                 }
 802
 803                 try {
 804                         $parser = MediaWikiServices::getInstance()->getTitleParser();
 805                         $parser->parseTitle( $this->mDbkeyform, $this->mNamespace );
 806                         return true;
 807                 } catch ( MalformedTitleException $ex ) {
 808                         return false;
 809                 }
 810         }
 811
 812         /**
 813          * Determine whether the object refers to a page within
 814          * this project (either this wiki or a wiki with a local
 815          * interwiki, see https://www.mediawiki.org/wiki/Manual:Interwiki_table#iw_local )
 816          *
 817          * @return bool True if this is an in-project interwiki link or a wikilink, false otherwise
 818          */
 819         public function isLocal() {
 820                 if ( $this->isExternal() ) {
 821                         $iw = self::getInterwikiLookup()->fetch( $this->mInterwiki );
 822                         if ( $iw ) {
 823                                 return $iw->isLocal();
 824                         }
 825                 }
 826                 return true;
 827         }
 828
 829         /**
 830          * Is this Title interwiki?
 831          *
 832          * @return bool
 833          */
 834         public function isExternal() {
 835                 return $this->mInterwiki !== '';
 836         }
 837
 838         /**
 839          * Get the interwiki prefix
 840          *
 841          * Use Title::isExternal to check if a interwiki is set
 842          *
 843          * @return string Interwiki prefix
 844          */
 845         public function getInterwiki() {
 846                 return $this->mInterwiki;
 847         }
 848
 849         /**
 850          * Was this a local interwiki link?
 851          *
 852          * @return bool
 853          */
 854         public function wasLocalInterwiki() {
 855                 return $this->mLocalInterwiki;
 856         }
 857
 858         /**
 859          * Determine whether the object refers to a page within
 860          * this project and is transcludable.
 861          *
 862          * @return bool True if this is transcludable
 863          */
 864         public function isTrans() {
 865                 if ( !$this->isExternal() ) {
 866                         return false;
 867                 }
 868
 869                 return self::getInterwikiLookup()->fetch( $this->mInterwiki )->isTranscludable();
 870         }
 871
 872         /**
 873          * Returns the DB name of the distant wiki which owns the object.
 874          *
 875          * @return string|false The DB name
 876          */
 877         public function getTransWikiID() {
 878                 if ( !$this->isExternal() ) {
 879                         return false;
 880                 }
 881
 882                 return self::getInterwikiLookup()->fetch( $this->mInterwiki )->getWikiID();
 883         }
 884
 885         /**
 886          * Get a TitleValue object representing this Title.
 887          *
 888          * @note Not all valid Titles have a corresponding valid TitleValue
 889          * (e.g. TitleValues cannot represent page-local links that have a
 890          * fragment but no title text).
 891          *
 892          * @return TitleValue|null
 893          */
 894         public function getTitleValue() {
 895                 if ( $this->mTitleValue === null ) {
 896                         try {
 897                                 $this->mTitleValue = new TitleValue(
 898                                         $this->mNamespace,
 899                                         $this->mDbkeyform,
 900                                         $this->mFragment,
 901                                         $this->mInterwiki
 902                                 );
 903                         } catch ( InvalidArgumentException $ex ) {
 904                                 wfDebug( __METHOD__ . ': Can\'t create a TitleValue for [[' .
 905                                         $this->getPrefixedText() . ']]: ' . $ex->getMessage() . "\n" );
 906                         }
 907                 }
 908
 909                 return $this->mTitleValue;
 910         }
 911
 912         /**
 913          * Get the text form (spaces not underscores) of the main part
 914          *
 915          * @return string Main part of the title
 916          */
 917         public function getText() {
 918                 return $this->mTextform;
 919         }
 920
 921         /**
 922          * Get the URL-encoded form of the main part
 923          *
 924          * @return string Main part of the title, URL-encoded
 925          */
 926         public function getPartialURL() {
 927                 return $this->mUrlform;
 928         }
 929
 930         /**
 931          * Get the main part with underscores
 932          *
 933          * @return string Main part of the title, with underscores
 934          */
 935         public function getDBkey() {
 936                 return $this->mDbkeyform;
 937         }
 938
 939         /**
 940          * Get the DB key with the initial letter case as specified by the user
 941          * @deprecated since 1.33; please use Title::getDBKey() instead
 942          *
 943          * @return string DB key
 944          */
 945         function getUserCaseDBKey() {
 946                 if ( !is_null( $this->mUserCaseDBKey ) ) {
 947                         return $this->mUserCaseDBKey;
 948                 } else {
 949                         // If created via makeTitle(), $this->mUserCaseDBKey is not set.
 950                         return $this->mDbkeyform;
 951                 }
 952         }
 953
 954         /**
 955          * Get the namespace index, i.e. one of the NS_xxxx constants.
 956          *
 957          * @return int Namespace index
 958          */
 959         public function getNamespace() {
 960                 return $this->mNamespace;
 961         }
 962
 963         /**
 964          * Get the page's content model id, see the CONTENT_MODEL_XXX constants.
 965          *
 966          * @todo Deprecate this in favor of SlotRecord::getModel()
 967          *
 968          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
 969          * @return string Content model id
 970          */
 971         public function getContentModel( $flags = 0 ) {
 972                 if ( !$this->mForcedContentModel
 973                         && ( !$this->mContentModel || $flags === self::GAID_FOR_UPDATE )
 974                         && $this->getArticleID( $flags )
 975                 ) {
 976                         $linkCache = MediaWikiServices::getInstance()->getLinkCache();
 977                         $linkCache->addLinkObj( $this ); # in case we already had an article ID
 978                         $this->mContentModel = $linkCache->getGoodLinkFieldObj( $this, 'model' );
 979                 }
 980
 981                 if ( !$this->mContentModel ) {
 982                         $this->mContentModel = ContentHandler::getDefaultModelFor( $this );
 983                 }
 984
 985                 return $this->mContentModel;
 986         }
 987
 988         /**
 989          * Convenience method for checking a title's content model name
 990          *
 991          * @param string $id The content model ID (use the CONTENT_MODEL_XXX constants).
 992          * @return bool True if $this->getContentModel() == $id
 993          */
 994         public function hasContentModel( $id ) {
 995                 return $this->getContentModel() == $id;
 996         }
 997
 998         /**
 999          * Set a proposed content model for the page for permissions
1000          * checking. This does not actually change the content model
1001          * of a title!
1002          *
1003          * Additionally, you should make sure you've checked
1004          * ContentHandler::canBeUsedOn() first.
1005          *
1006          * @since 1.28
1007          * @param string $model CONTENT_MODEL_XXX constant
1008          */
1009         public function setContentModel( $model ) {
1010                 $this->mContentModel = $model;
1011                 $this->mForcedContentModel = true;
1012         }
1013
1014         /**
1015          * Get the namespace text
1016          *
1017          * @return string|false Namespace text
1018          */
1019         public function getNsText() {
1020                 if ( $this->isExternal() ) {
1021                         // This probably shouldn't even happen, except for interwiki transclusion.
1022                         // If possible, use the canonical name for the foreign namespace.
1023                         $nsText = MWNamespace::getCanonicalName( $this->mNamespace );
1024                         if ( $nsText !== false ) {
1025                                 return $nsText;
1026                         }
1027                 }
1028
1029                 try {
1030                         $formatter = self::getTitleFormatter();
1031                         return $formatter->getNamespaceName( $this->mNamespace, $this->mDbkeyform );
1032                 } catch ( InvalidArgumentException $ex ) {
1033                         wfDebug( __METHOD__ . ': ' . $ex->getMessage() . "\n" );
1034                         return false;
1035                 }
1036         }
1037
1038         /**
1039          * Get the namespace text of the subject (rather than talk) page
1040          *
1041          * @return string Namespace text
1042          */
1043         public function getSubjectNsText() {
1044                 return MediaWikiServices::getInstance()->getContentLanguage()->
1045                         getNsText( MWNamespace::getSubject( $this->mNamespace ) );
1046         }
1047
1048         /**
1049          * Get the namespace text of the talk page
1050          *
1051          * @return string Namespace text
1052          */
1053         public function getTalkNsText() {
1054                 return MediaWikiServices::getInstance()->getContentLanguage()->
1055                         getNsText( MWNamespace::getTalk( $this->mNamespace ) );
1056         }
1057
1058         /**
1059          * Can this title have a corresponding talk page?
1060          *
1061          * @see MWNamespace::hasTalkNamespace
1062          * @since 1.30
1063          *
1064          * @return bool True if this title either is a talk page or can have a talk page associated.
1065          */
1066         public function canHaveTalkPage() {
1067                 return MWNamespace::hasTalkNamespace( $this->mNamespace );
1068         }
1069
1070         /**
1071          * Is this in a namespace that allows actual pages?
1072          *
1073          * @return bool
1074          */
1075         public function canExist() {
1076                 return $this->mNamespace >= NS_MAIN;
1077         }
1078
1079         /**
1080          * Can this title be added to a user's watchlist?
1081          *
1082          * @return bool
1083          */
1084         public function isWatchable() {
1085                 return !$this->isExternal() && MWNamespace::isWatchable( $this->mNamespace );
1086         }
1087
1088         /**
1089          * Returns true if this is a special page.
1090          *
1091          * @return bool
1092          */
1093         public function isSpecialPage() {
1094                 return $this->mNamespace == NS_SPECIAL;
1095         }
1096
1097         /**
1098          * Returns true if this title resolves to the named special page
1099          *
1100          * @param string $name The special page name
1101          * @return bool
1102          */
1103         public function isSpecial( $name ) {
1104                 if ( $this->isSpecialPage() ) {
1105                         list( $thisName, /* $subpage */ ) =
1106                                 MediaWikiServices::getInstance()->getSpecialPageFactory()->
1107                                         resolveAlias( $this->mDbkeyform );
1108                         if ( $name == $thisName ) {
1109                                 return true;
1110                         }
1111                 }
1112                 return false;
1113         }
1114
1115         /**
1116          * If the Title refers to a special page alias which is not the local default, resolve
1117          * the alias, and localise the name as necessary.  Otherwise, return $this
1118          *
1119          * @return Title
1120          */
1121         public function fixSpecialName() {
1122                 if ( $this->isSpecialPage() ) {
1123                         $spFactory = MediaWikiServices::getInstance()->getSpecialPageFactory();
1124                         list( $canonicalName, $par ) = $spFactory->resolveAlias( $this->mDbkeyform );
1125                         if ( $canonicalName ) {
1126                                 $localName = $spFactory->getLocalNameFor( $canonicalName, $par );
1127                                 if ( $localName != $this->mDbkeyform ) {
1128                                         return self::makeTitle( NS_SPECIAL, $localName );
1129                                 }
1130                         }
1131                 }
1132                 return $this;
1133         }
1134
1135         /**
1136          * Returns true if the title is inside the specified namespace.
1137          *
1138          * Please make use of this instead of comparing to getNamespace()
1139          * This function is much more resistant to changes we may make
1140          * to namespaces than code that makes direct comparisons.
1141          * @param int $ns The namespace
1142          * @return bool
1143          * @since 1.19
1144          */
1145         public function inNamespace( $ns ) {
1146                 return MWNamespace::equals( $this->mNamespace, $ns );
1147         }
1148
1149         /**
1150          * Returns true if the title is inside one of the specified namespaces.
1151          *
1152          * @param int|int[] $namespaces,... The namespaces to check for
1153          * @return bool
1154          * @since 1.19
1155          */
1156         public function inNamespaces( /* ... */ ) {
1157                 $namespaces = func_get_args();
1158                 if ( count( $namespaces ) > 0 && is_array( $namespaces[0] ) ) {
1159                         $namespaces = $namespaces[0];
1160                 }
1161
1162                 foreach ( $namespaces as $ns ) {
1163                         if ( $this->inNamespace( $ns ) ) {
1164                                 return true;
1165                         }
1166                 }
1167
1168                 return false;
1169         }
1170
1171         /**
1172          * Returns true if the title has the same subject namespace as the
1173          * namespace specified.
1174          * For example this method will take NS_USER and return true if namespace
1175          * is either NS_USER or NS_USER_TALK since both of them have NS_USER
1176          * as their subject namespace.
1177          *
1178          * This is MUCH simpler than individually testing for equivalence
1179          * against both NS_USER and NS_USER_TALK, and is also forward compatible.
1180          * @since 1.19
1181          * @param int $ns
1182          * @return bool
1183          */
1184         public function hasSubjectNamespace( $ns ) {
1185                 return MWNamespace::subjectEquals( $this->mNamespace, $ns );
1186         }
1187
1188         /**
1189          * Is this Title in a namespace which contains content?
1190          * In other words, is this a content page, for the purposes of calculating
1191          * statistics, etc?
1192          *
1193          * @return bool
1194          */
1195         public function isContentPage() {
1196                 return MWNamespace::isContent( $this->mNamespace );
1197         }
1198
1199         /**
1200          * Would anybody with sufficient privileges be able to move this page?
1201          * Some pages just aren't movable.
1202          *
1203          * @return bool
1204          */
1205         public function isMovable() {
1206                 if ( !MWNamespace::isMovable( $this->mNamespace ) || $this->isExternal() ) {
1207                         // Interwiki title or immovable namespace. Hooks don't get to override here
1208                         return false;
1209                 }
1210
1211                 $result = true;
1212                 Hooks::run( 'TitleIsMovable', [ $this, &$result ] );
1213                 return $result;
1214         }
1215
1216         /**
1217          * Is this the mainpage?
1218          * @note Title::newFromText seems to be sufficiently optimized by the title
1219          * cache that we don't need to over-optimize by doing direct comparisons and
1220          * accidentally creating new bugs where $title->equals( Title::newFromText() )
1221          * ends up reporting something differently than $title->isMainPage();
1222          *
1223          * @since 1.18
1224          * @return bool
1225          */
1226         public function isMainPage() {
1227                 return $this->equals( self::newMainPage() );
1228         }
1229
1230         /**
1231          * Is this a subpage?
1232          *
1233          * @return bool
1234          */
1235         public function isSubpage() {
1236                 return MWNamespace::hasSubpages( $this->mNamespace )
1237                         ? strpos( $this->getText(), '/' ) !== false
1238                         : false;
1239         }
1240
1241         /**
1242          * Is this a conversion table for the LanguageConverter?
1243          *
1244          * @return bool
1245          */
1246         public function isConversionTable() {
1247                 // @todo ConversionTable should become a separate content model.
1248
1249                 return $this->mNamespace == NS_MEDIAWIKI &&
1250                         strpos( $this->getText(), 'Conversiontable/' ) === 0;
1251         }
1252
1253         /**
1254          * Does that page contain wikitext, or it is JS, CSS or whatever?
1255          *
1256          * @return bool
1257          */
1258         public function isWikitextPage() {
1259                 return $this->hasContentModel( CONTENT_MODEL_WIKITEXT );
1260         }
1261
1262         /**
1263          * Could this MediaWiki namespace page contain custom CSS, JSON, or JavaScript for the
1264          * global UI. This is generally true for pages in the MediaWiki namespace having
1265          * CONTENT_MODEL_CSS, CONTENT_MODEL_JSON, or CONTENT_MODEL_JAVASCRIPT.
1266          *
1267          * This method does *not* return true for per-user JS/JSON/CSS. Use isUserConfigPage()
1268          * for that!
1269          *
1270          * Note that this method should not return true for pages that contain and show
1271          * "inactive" CSS, JSON, or JS.
1272          *
1273          * @return bool
1274          * @since 1.31
1275          */
1276         public function isSiteConfigPage() {
1277                 return (
1278                         $this->isSiteCssConfigPage()
1279                         || $this->isSiteJsonConfigPage()
1280                         || $this->isSiteJsConfigPage()
1281                 );
1282         }
1283
1284         /**
1285          * Is this a "config" (.css, .json, or .js) sub-page of a user page?
1286          *
1287          * @return bool
1288          * @since 1.31
1289          */
1290         public function isUserConfigPage() {
1291                 return (
1292                         $this->isUserCssConfigPage()
1293                         || $this->isUserJsonConfigPage()
1294                         || $this->isUserJsConfigPage()
1295                 );
1296         }
1297
1298         /**
1299          * Trim down a .css, .json, or .js subpage title to get the corresponding skin name
1300          *
1301          * @return string Containing skin name from .css, .json, or .js subpage title
1302          * @since 1.31
1303          */
1304         public function getSkinFromConfigSubpage() {
1305                 $subpage = explode( '/', $this->mTextform );
1306                 $subpage = $subpage[count( $subpage ) - 1];
1307                 $lastdot = strrpos( $subpage, '.' );
1308                 if ( $lastdot === false ) {
1309                         return $subpage; # Never happens: only called for names ending in '.css'/'.json'/'.js'
1310                 }
1311                 return substr( $subpage, 0, $lastdot );
1312         }
1313
1314         /**
1315          * Is this a CSS "config" sub-page of a user page?
1316          *
1317          * @return bool
1318          * @since 1.31
1319          */
1320         public function isUserCssConfigPage() {
1321                 return (
1322                         NS_USER == $this->mNamespace
1323                         && $this->isSubpage()
1324                         && $this->hasContentModel( CONTENT_MODEL_CSS )
1325                 );
1326         }
1327
1328         /**
1329          * Is this a JSON "config" sub-page of a user page?
1330          *
1331          * @return bool
1332          * @since 1.31
1333          */
1334         public function isUserJsonConfigPage() {
1335                 return (
1336                         NS_USER == $this->mNamespace
1337                         && $this->isSubpage()
1338                         && $this->hasContentModel( CONTENT_MODEL_JSON )
1339                 );
1340         }
1341
1342         /**
1343          * Is this a JS "config" sub-page of a user page?
1344          *
1345          * @return bool
1346          * @since 1.31
1347          */
1348         public function isUserJsConfigPage() {
1349                 return (
1350                         NS_USER == $this->mNamespace
1351                         && $this->isSubpage()
1352                         && $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT )
1353                 );
1354         }
1355
1356         /**
1357          * Is this a sitewide CSS "config" page?
1358          *
1359          * @return bool
1360          * @since 1.32
1361          */
1362         public function isSiteCssConfigPage() {
1363                 return (
1364                         NS_MEDIAWIKI == $this->mNamespace
1365                         && (
1366                                 $this->hasContentModel( CONTENT_MODEL_CSS )
1367                                 // paranoia - a MediaWiki: namespace page with mismatching extension and content
1368                                 // model is probably by mistake and might get handled incorrectly (see e.g. T112937)
1369                                 || substr( $this->mDbkeyform, -4 ) === '.css'
1370                         )
1371                 );
1372         }
1373
1374         /**
1375          * Is this a sitewide JSON "config" page?
1376          *
1377          * @return bool
1378          * @since 1.32
1379          */
1380         public function isSiteJsonConfigPage() {
1381                 return (
1382                         NS_MEDIAWIKI == $this->mNamespace
1383                         && (
1384                                 $this->hasContentModel( CONTENT_MODEL_JSON )
1385                                 // paranoia - a MediaWiki: namespace page with mismatching extension and content
1386                                 // model is probably by mistake and might get handled incorrectly (see e.g. T112937)
1387                                 || substr( $this->mDbkeyform, -5 ) === '.json'
1388                         )
1389                 );
1390         }
1391
1392         /**
1393          * Is this a sitewide JS "config" page?
1394          *
1395          * @return bool
1396          * @since 1.31
1397          */
1398         public function isSiteJsConfigPage() {
1399                 return (
1400                         NS_MEDIAWIKI == $this->mNamespace
1401                         && (
1402                                 $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT )
1403                                 // paranoia - a MediaWiki: namespace page with mismatching extension and content
1404                                 // model is probably by mistake and might get handled incorrectly (see e.g. T112937)
1405                                 || substr( $this->mDbkeyform, -3 ) === '.js'
1406                         )
1407                 );
1408         }
1409
1410         /**
1411          * Is this a message which can contain raw HTML?
1412          *
1413          * @return bool
1414          * @since 1.32
1415          */
1416         public function isRawHtmlMessage() {
1417                 global $wgRawHtmlMessages;
1418
1419                 if ( !$this->inNamespace( NS_MEDIAWIKI ) ) {
1420                         return false;
1421                 }
1422                 $message = lcfirst( $this->getRootTitle()->getDBkey() );
1423                 return in_array( $message, $wgRawHtmlMessages, true );
1424         }
1425
1426         /**
1427          * Is this a talk page of some sort?
1428          *
1429          * @return bool
1430          */
1431         public function isTalkPage() {
1432                 return MWNamespace::isTalk( $this->mNamespace );
1433         }
1434
1435         /**
1436          * Get a Title object associated with the talk page of this article
1437          *
1438          * @return Title The object for the talk page
1439          */
1440         public function getTalkPage() {
1441                 return self::makeTitle( MWNamespace::getTalk( $this->mNamespace ), $this->mDbkeyform );
1442         }
1443
1444         /**
1445          * Get a Title object associated with the talk page of this article,
1446          * if such a talk page can exist.
1447          *
1448          * @since 1.30
1449          *
1450          * @return Title|null The object for the talk page,
1451          *         or null if no associated talk page can exist, according to canHaveTalkPage().
1452          */
1453         public function getTalkPageIfDefined() {
1454                 if ( !$this->canHaveTalkPage() ) {
1455                         return null;
1456                 }
1457
1458                 return $this->getTalkPage();
1459         }
1460
1461         /**
1462          * Get a title object associated with the subject page of this
1463          * talk page
1464          *
1465          * @return Title The object for the subject page
1466          */
1467         public function getSubjectPage() {
1468                 // Is this the same title?
1469                 $subjectNS = MWNamespace::getSubject( $this->mNamespace );
1470                 if ( $this->mNamespace == $subjectNS ) {
1471                         return $this;
1472                 }
1473                 return self::makeTitle( $subjectNS, $this->mDbkeyform );
1474         }
1475
1476         /**
1477          * Get the other title for this page, if this is a subject page
1478          * get the talk page, if it is a subject page get the talk page
1479          *
1480          * @since 1.25
1481          * @throws MWException If the page doesn't have an other page
1482          * @return Title
1483          */
1484         public function getOtherPage() {
1485                 if ( $this->isSpecialPage() ) {
1486                         throw new MWException( 'Special pages cannot have other pages' );
1487                 }
1488                 if ( $this->isTalkPage() ) {
1489                         return $this->getSubjectPage();
1490                 } else {
1491                         if ( !$this->canHaveTalkPage() ) {
1492                                 throw new MWException( "{$this->getPrefixedText()} does not have an other page" );
1493                         }
1494                         return $this->getTalkPage();
1495                 }
1496         }
1497
1498         /**
1499          * Get the default namespace index, for when there is no namespace
1500          *
1501          * @return int Default namespace index
1502          */
1503         public function getDefaultNamespace() {
1504                 return $this->mDefaultNamespace;
1505         }
1506
1507         /**
1508          * Get the Title fragment (i.e.\ the bit after the #) in text form
1509          *
1510          * Use Title::hasFragment to check for a fragment
1511          *
1512          * @return string Title fragment
1513          */
1514         public function getFragment() {
1515                 return $this->mFragment;
1516         }
1517
1518         /**
1519          * Check if a Title fragment is set
1520          *
1521          * @return bool
1522          * @since 1.23
1523          */
1524         public function hasFragment() {
1525                 return $this->mFragment !== '';
1526         }
1527
1528         /**
1529          * Get the fragment in URL form, including the "#" character if there is one
1530          *
1531          * @return string Fragment in URL form
1532          */
1533         public function getFragmentForURL() {
1534                 if ( !$this->hasFragment() ) {
1535                         return '';
1536                 } elseif ( $this->isExternal() ) {
1537                         // Note: If the interwiki is unknown, it's treated as a namespace on the local wiki,
1538                         // so we treat it like a local interwiki.
1539                         $interwiki = self::getInterwikiLookup()->fetch( $this->mInterwiki );
1540                         if ( $interwiki && !$interwiki->isLocal() ) {
1541                                 return '#' . Sanitizer::escapeIdForExternalInterwiki( $this->mFragment );
1542                         }
1543                 }
1544
1545                 return '#' . Sanitizer::escapeIdForLink( $this->mFragment );
1546         }
1547
1548         /**
1549          * Set the fragment for this title. Removes the first character from the
1550          * specified fragment before setting, so it assumes you're passing it with
1551          * an initial "#".
1552          *
1553          * Deprecated for public use, use Title::makeTitle() with fragment parameter,
1554          * or Title::createFragmentTarget().
1555          * Still in active use privately.
1556          *
1557          * @private
1558          * @param string $fragment Text
1559          */
1560         public function setFragment( $fragment ) {
1561                 $this->mFragment = strtr( substr( $fragment, 1 ), '_', ' ' );
1562         }
1563
1564         /**
1565          * Creates a new Title for a different fragment of the same page.
1566          *
1567          * @since 1.27
1568          * @param string $fragment
1569          * @return Title
1570          */
1571         public function createFragmentTarget( $fragment ) {
1572                 return self::makeTitle(
1573                         $this->mNamespace,
1574                         $this->getText(),
1575                         $fragment,
1576                         $this->mInterwiki
1577                 );
1578         }
1579
1580         /**
1581          * Prefix some arbitrary text with the namespace or interwiki prefix
1582          * of this object
1583          *
1584          * @param string $name The text
1585          * @return string The prefixed text
1586          */
1587         private function prefix( $name ) {
1588                 $p = '';
1589                 if ( $this->isExternal() ) {
1590                         $p = $this->mInterwiki . ':';
1591                 }
1592
1593                 if ( $this->mNamespace != 0 ) {
1594                         $nsText = $this->getNsText();
1595
1596                         if ( $nsText === false ) {
1597                                 // See T165149. Awkward, but better than erroneously linking to the main namespace.
1598                                 $nsText = MediaWikiServices::getInstance()->getContentLanguage()->
1599                                         getNsText( NS_SPECIAL ) . ":Badtitle/NS{$this->mNamespace}";
1600                         }
1601
1602                         $p .= $nsText . ':';
1603                 }
1604                 return $p . $name;
1605         }
1606
1607         /**
1608          * Get the prefixed database key form
1609          *
1610          * @return string The prefixed title, with underscores and
1611          *  any interwiki and namespace prefixes
1612          */
1613         public function getPrefixedDBkey() {
1614                 $s = $this->prefix( $this->mDbkeyform );
1615                 $s = strtr( $s, ' ', '_' );
1616                 return $s;
1617         }
1618
1619         /**
1620          * Get the prefixed title with spaces.
1621          * This is the form usually used for display
1622          *
1623          * @return string The prefixed title, with spaces
1624          */
1625         public function getPrefixedText() {
1626                 if ( $this->prefixedText === null ) {
1627                         $s = $this->prefix( $this->mTextform );
1628                         $s = strtr( $s, '_', ' ' );
1629                         $this->prefixedText = $s;
1630                 }
1631                 return $this->prefixedText;
1632         }
1633
1634         /**
1635          * Return a string representation of this title
1636          *
1637          * @return string Representation of this title
1638          */
1639         public function __toString() {
1640                 return $this->getPrefixedText();
1641         }
1642
1643         /**
1644          * Get the prefixed title with spaces, plus any fragment
1645          * (part beginning with '#')
1646          *
1647          * @return string The prefixed title, with spaces and the fragment, including '#'
1648          */
1649         public function getFullText() {
1650                 $text = $this->getPrefixedText();
1651                 if ( $this->hasFragment() ) {
1652                         $text .= '#' . $this->mFragment;
1653                 }
1654                 return $text;
1655         }
1656
1657         /**
1658          * Get the root page name text without a namespace, i.e. the leftmost part before any slashes
1659          *
1660          * @par Example:
1661          * @code
1662          * Title::newFromText('User:Foo/Bar/Baz')->getRootText();
1663          * # returns: 'Foo'
1664          * @endcode
1665          *
1666          * @return string Root name
1667          * @since 1.20
1668          */
1669         public function getRootText() {
1670                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1671                         return $this->getText();
1672                 }
1673
1674                 return strtok( $this->getText(), '/' );
1675         }
1676
1677         /**
1678          * Get the root page name title, i.e. the leftmost part before any slashes
1679          *
1680          * @par Example:
1681          * @code
1682          * Title::newFromText('User:Foo/Bar/Baz')->getRootTitle();
1683          * # returns: Title{User:Foo}
1684          * @endcode
1685          *
1686          * @return Title Root title
1687          * @since 1.20
1688          */
1689         public function getRootTitle() {
1690                 return self::makeTitle( $this->mNamespace, $this->getRootText() );
1691         }
1692
1693         /**
1694          * Get the base page name without a namespace, i.e. the part before the subpage name
1695          *
1696          * @par Example:
1697          * @code
1698          * Title::newFromText('User:Foo/Bar/Baz')->getBaseText();
1699          * # returns: 'Foo/Bar'
1700          * @endcode
1701          *
1702          * @return string Base name
1703          */
1704         public function getBaseText() {
1705                 $text = $this->getText();
1706                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1707                         return $text;
1708                 }
1709
1710                 $lastSlashPos = strrpos( $text, '/' );
1711                 // Don't discard the real title if there's no subpage involved
1712                 if ( $lastSlashPos === false ) {
1713                         return $text;
1714                 }
1715
1716                 return substr( $text, 0, $lastSlashPos );
1717         }
1718
1719         /**
1720          * Get the base page name title, i.e. the part before the subpage name
1721          *
1722          * @par Example:
1723          * @code
1724          * Title::newFromText('User:Foo/Bar/Baz')->getBaseTitle();
1725          * # returns: Title{User:Foo/Bar}
1726          * @endcode
1727          *
1728          * @return Title Base title
1729          * @since 1.20
1730          */
1731         public function getBaseTitle() {
1732                 return self::makeTitle( $this->mNamespace, $this->getBaseText() );
1733         }
1734
1735         /**
1736          * Get the lowest-level subpage name, i.e. the rightmost part after any slashes
1737          *
1738          * @par Example:
1739          * @code
1740          * Title::newFromText('User:Foo/Bar/Baz')->getSubpageText();
1741          * # returns: "Baz"
1742          * @endcode
1743          *
1744          * @return string Subpage name
1745          */
1746         public function getSubpageText() {
1747                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1748                         return $this->mTextform;
1749                 }
1750                 $parts = explode( '/', $this->mTextform );
1751                 return $parts[count( $parts ) - 1];
1752         }
1753
1754         /**
1755          * Get the title for a subpage of the current page
1756          *
1757          * @par Example:
1758          * @code
1759          * Title::newFromText('User:Foo/Bar/Baz')->getSubpage("Asdf");
1760          * # returns: Title{User:Foo/Bar/Baz/Asdf}
1761          * @endcode
1762          *
1763          * @param string $text The subpage name to add to the title
1764          * @return Title|null Subpage title, or null on an error
1765          * @since 1.20
1766          */
1767         public function getSubpage( $text ) {
1768                 return self::makeTitleSafe( $this->mNamespace, $this->getText() . '/' . $text );
1769         }
1770
1771         /**
1772          * Get a URL-encoded form of the subpage text
1773          *
1774          * @return string URL-encoded subpage name
1775          */
1776         public function getSubpageUrlForm() {
1777                 $text = $this->getSubpageText();
1778                 $text = wfUrlencode( strtr( $text, ' ', '_' ) );
1779                 return $text;
1780         }
1781
1782         /**
1783          * Get a URL-encoded title (not an actual URL) including interwiki
1784          *
1785          * @return string The URL-encoded form
1786          */
1787         public function getPrefixedURL() {
1788                 $s = $this->prefix( $this->mDbkeyform );
1789                 $s = wfUrlencode( strtr( $s, ' ', '_' ) );
1790                 return $s;
1791         }
1792
1793         /**
1794          * Helper to fix up the get{Canonical,Full,Link,Local,Internal}URL args
1795          * get{Canonical,Full,Link,Local,Internal}URL methods accepted an optional
1796          * second argument named variant. This was deprecated in favor
1797          * of passing an array of option with a "variant" key
1798          * Once $query2 is removed for good, this helper can be dropped
1799          * and the wfArrayToCgi moved to getLocalURL();
1800          *
1801          * @since 1.19 (r105919)
1802          * @param array|string $query
1803          * @param string|string[]|bool $query2
1804          * @return string
1805          */
1806         private static function fixUrlQueryArgs( $query, $query2 = false ) {
1807                 if ( $query2 !== false ) {
1808                         wfDeprecated( "Title::get{Canonical,Full,Link,Local,Internal}URL " .
1809                                 "method called with a second parameter is deprecated. Add your " .
1810                                 "parameter to an array passed as the first parameter.", "1.19" );
1811                 }
1812                 if ( is_array( $query ) ) {
1813                         $query = wfArrayToCgi( $query );
1814                 }
1815                 if ( $query2 ) {
1816                         if ( is_string( $query2 ) ) {
1817                                 // $query2 is a string, we will consider this to be
1818                                 // a deprecated $variant argument and add it to the query
1819                                 $query2 = wfArrayToCgi( [ 'variant' => $query2 ] );
1820                         } else {
1821                                 $query2 = wfArrayToCgi( $query2 );
1822                         }
1823                         // If we have $query content add a & to it first
1824                         if ( $query ) {
1825                                 $query .= '&';
1826                         }
1827                         // Now append the queries together
1828                         $query .= $query2;
1829                 }
1830                 return $query;
1831         }
1832
1833         /**
1834          * Get a real URL referring to this title, with interwiki link and
1835          * fragment
1836          *
1837          * @see self::getLocalURL for the arguments.
1838          * @see wfExpandUrl
1839          * @param string|string[] $query
1840          * @param string|string[]|bool $query2
1841          * @param string|int|null $proto Protocol type to use in URL
1842          * @return string The URL
1843          */
1844         public function getFullURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1845                 $query = self::fixUrlQueryArgs( $query, $query2 );
1846
1847                 # Hand off all the decisions on urls to getLocalURL
1848                 $url = $this->getLocalURL( $query );
1849
1850                 # Expand the url to make it a full url. Note that getLocalURL has the
1851                 # potential to output full urls for a variety of reasons, so we use
1852                 # wfExpandUrl instead of simply prepending $wgServer
1853                 $url = wfExpandUrl( $url, $proto );
1854
1855                 # Finally, add the fragment.
1856                 $url .= $this->getFragmentForURL();
1857                 // Avoid PHP 7.1 warning from passing $this by reference
1858                 $titleRef = $this;
1859                 Hooks::run( 'GetFullURL', [ &$titleRef, &$url, $query ] );
1860                 return $url;
1861         }
1862
1863         /**
1864          * Get a url appropriate for making redirects based on an untrusted url arg
1865          *
1866          * This is basically the same as getFullUrl(), but in the case of external
1867          * interwikis, we send the user to a landing page, to prevent possible
1868          * phishing attacks and the like.
1869          *
1870          * @note Uses current protocol by default, since technically relative urls
1871          *   aren't allowed in redirects per HTTP spec, so this is not suitable for
1872          *   places where the url gets cached, as might pollute between
1873          *   https and non-https users.
1874          * @see self::getLocalURL for the arguments.
1875          * @param array|string $query
1876          * @param string $proto Protocol type to use in URL
1877          * @return string A url suitable to use in an HTTP location header.
1878          */
1879         public function getFullUrlForRedirect( $query = '', $proto = PROTO_CURRENT ) {
1880                 $target = $this;
1881                 if ( $this->isExternal() ) {
1882                         $target = SpecialPage::getTitleFor(
1883                                 'GoToInterwiki',
1884                                 $this->getPrefixedDBkey()
1885                         );
1886                 }
1887                 return $target->getFullURL( $query, false, $proto );
1888         }
1889
1890         /**
1891          * Get a URL with no fragment or server name (relative URL) from a Title object.
1892          * If this page is generated with action=render, however,
1893          * $wgServer is prepended to make an absolute URL.
1894          *
1895          * @see self::getFullURL to always get an absolute URL.
1896          * @see self::getLinkURL to always get a URL that's the simplest URL that will be
1897          *  valid to link, locally, to the current Title.
1898          * @see self::newFromText to produce a Title object.
1899          *
1900          * @param string|string[] $query An optional query string,
1901          *   not used for interwiki links. Can be specified as an associative array as well,
1902          *   e.g., array( 'action' => 'edit' ) (keys and values will be URL-escaped).
1903          *   Some query patterns will trigger various shorturl path replacements.
1904          * @param string|string[]|bool $query2 An optional secondary query array. This one MUST
1905          *   be an array. If a string is passed it will be interpreted as a deprecated
1906          *   variant argument and urlencoded into a variant= argument.
1907          *   This second query argument will be added to the $query
1908          *   The second parameter is deprecated since 1.19. Pass it as a key,value
1909          *   pair in the first parameter array instead.
1910          *
1911          * @return string String of the URL.
1912          */
1913         public function getLocalURL( $query = '', $query2 = false ) {
1914                 global $wgArticlePath, $wgScript, $wgServer, $wgRequest;
1915
1916                 $query = self::fixUrlQueryArgs( $query, $query2 );
1917
1918                 $interwiki = self::getInterwikiLookup()->fetch( $this->mInterwiki );
1919                 if ( $interwiki ) {
1920                         $namespace = $this->getNsText();
1921                         if ( $namespace != '' ) {
1922                                 # Can this actually happen? Interwikis shouldn't be parsed.
1923                                 # Yes! It can in interwiki transclusion. But... it probably shouldn't.
1924                                 $namespace .= ':';
1925                         }
1926                         $url = $interwiki->getURL( $namespace . $this->mDbkeyform );
1927                         $url = wfAppendQuery( $url, $query );
1928                 } else {
1929                         $dbkey = wfUrlencode( $this->getPrefixedDBkey() );
1930                         if ( $query == '' ) {
1931                                 $url = str_replace( '$1', $dbkey, $wgArticlePath );
1932                                 // Avoid PHP 7.1 warning from passing $this by reference
1933                                 $titleRef = $this;
1934                                 Hooks::run( 'GetLocalURL::Article', [ &$titleRef, &$url ] );
1935                         } else {
1936                                 global $wgVariantArticlePath, $wgActionPaths;
1937                                 $url = false;
1938                                 $matches = [];
1939
1940                                 if ( !empty( $wgActionPaths )
1941                                         && preg_match( '/^(.*&|)action=([^&]*)(&(.*)|)$/', $query, $matches )
1942                                 ) {
1943                                         $action = urldecode( $matches[2] );
1944                                         if ( isset( $wgActionPaths[$action] ) ) {
1945                                                 $query = $matches[1];
1946                                                 if ( isset( $matches[4] ) ) {
1947                                                         $query .= $matches[4];
1948                                                 }
1949                                                 $url = str_replace( '$1', $dbkey, $wgActionPaths[$action] );
1950                                                 if ( $query != '' ) {
1951                                                         $url = wfAppendQuery( $url, $query );
1952                                                 }
1953                                         }
1954                                 }
1955
1956                                 if ( $url === false
1957                                         && $wgVariantArticlePath
1958                                         && preg_match( '/^variant=([^&]*)$/', $query, $matches )
1959                                         && $this->getPageLanguage()->equals(
1960                                                 MediaWikiServices::getInstance()->getContentLanguage() )
1961                                         && $this->getPageLanguage()->hasVariants()
1962                                 ) {
1963                                         $variant = urldecode( $matches[1] );
1964                                         if ( $this->getPageLanguage()->hasVariant( $variant ) ) {
1965                                                 // Only do the variant replacement if the given variant is a valid
1966                                                 // variant for the page's language.
1967                                                 $url = str_replace( '$2', urlencode( $variant ), $wgVariantArticlePath );
1968                                                 $url = str_replace( '$1', $dbkey, $url );
1969                                         }
1970                                 }
1971
1972                                 if ( $url === false ) {
1973                                         if ( $query == '-' ) {
1974                                                 $query = '';
1975                                         }
1976                                         $url = "{$wgScript}?title={$dbkey}&{$query}";
1977                                 }
1978                         }
1979                         // Avoid PHP 7.1 warning from passing $this by reference
1980                         $titleRef = $this;
1981                         Hooks::run( 'GetLocalURL::Internal', [ &$titleRef, &$url, $query ] );
1982
1983                         // @todo FIXME: This causes breakage in various places when we
1984                         // actually expected a local URL and end up with dupe prefixes.
1985                         if ( $wgRequest->getVal( 'action' ) == 'render' ) {
1986                                 $url = $wgServer . $url;
1987                         }
1988                 }
1989                 // Avoid PHP 7.1 warning from passing $this by reference
1990                 $titleRef = $this;
1991                 Hooks::run( 'GetLocalURL', [ &$titleRef, &$url, $query ] );
1992                 return $url;
1993         }
1994
1995         /**
1996          * Get a URL that's the simplest URL that will be valid to link, locally,
1997          * to the current Title.  It includes the fragment, but does not include
1998          * the server unless action=render is used (or the link is external).  If
1999          * there's a fragment but the prefixed text is empty, we just return a link
2000          * to the fragment.
2001          *
2002          * The result obviously should not be URL-escaped, but does need to be
2003          * HTML-escaped if it's being output in HTML.
2004          *
2005          * @param string|string[] $query
2006          * @param bool $query2
2007          * @param string|int|bool $proto A PROTO_* constant on how the URL should be expanded,
2008          *                               or false (default) for no expansion
2009          * @see self::getLocalURL for the arguments.
2010          * @return string The URL
2011          */
2012         public function getLinkURL( $query = '', $query2 = false, $proto = false ) {
2013                 if ( $this->isExternal() || $proto !== false ) {
2014                         $ret = $this->getFullURL( $query, $query2, $proto );
2015                 } elseif ( $this->getPrefixedText() === '' && $this->hasFragment() ) {
2016                         $ret = $this->getFragmentForURL();
2017                 } else {
2018                         $ret = $this->getLocalURL( $query, $query2 ) . $this->getFragmentForURL();
2019                 }
2020                 return $ret;
2021         }
2022
2023         /**
2024          * Get the URL form for an internal link.
2025          * - Used in various CDN-related code, in case we have a different
2026          * internal hostname for the server from the exposed one.
2027          *
2028          * This uses $wgInternalServer to qualify the path, or $wgServer
2029          * if $wgInternalServer is not set. If the server variable used is
2030          * protocol-relative, the URL will be expanded to http://
2031          *
2032          * @see self::getLocalURL for the arguments.
2033          * @param string $query
2034          * @param string|bool $query2
2035          * @return string The URL
2036          */
2037         public function getInternalURL( $query = '', $query2 = false ) {
2038                 global $wgInternalServer, $wgServer;
2039                 $query = self::fixUrlQueryArgs( $query, $query2 );
2040                 $server = $wgInternalServer !== false ? $wgInternalServer : $wgServer;
2041                 $url = wfExpandUrl( $server . $this->getLocalURL( $query ), PROTO_HTTP );
2042                 // Avoid PHP 7.1 warning from passing $this by reference
2043                 $titleRef = $this;
2044                 Hooks::run( 'GetInternalURL', [ &$titleRef, &$url, $query ] );
2045                 return $url;
2046         }
2047
2048         /**
2049          * Get the URL for a canonical link, for use in things like IRC and
2050          * e-mail notifications. Uses $wgCanonicalServer and the
2051          * GetCanonicalURL hook.
2052          *
2053          * NOTE: Unlike getInternalURL(), the canonical URL includes the fragment
2054          *
2055          * @see self::getLocalURL for the arguments.
2056          * @param string $query
2057          * @param string|bool $query2
2058          * @return string The URL
2059          * @since 1.18
2060          */
2061         public function getCanonicalURL( $query = '', $query2 = false ) {
2062                 $query = self::fixUrlQueryArgs( $query, $query2 );
2063                 $url = wfExpandUrl( $this->getLocalURL( $query ) . $this->getFragmentForURL(), PROTO_CANONICAL );
2064                 // Avoid PHP 7.1 warning from passing $this by reference
2065                 $titleRef = $this;
2066                 Hooks::run( 'GetCanonicalURL', [ &$titleRef, &$url, $query ] );
2067                 return $url;
2068         }
2069
2070         /**
2071          * Get the edit URL for this Title
2072          *
2073          * @return string The URL, or a null string if this is an interwiki link
2074          */
2075         public function getEditURL() {
2076                 if ( $this->isExternal() ) {
2077                         return '';
2078                 }
2079                 $s = $this->getLocalURL( 'action=edit' );
2080
2081                 return $s;
2082         }
2083
2084         /**
2085          * Can $user perform $action on this page?
2086          * This skips potentially expensive cascading permission checks
2087          * as well as avoids expensive error formatting
2088          *
2089          * Suitable for use for nonessential UI controls in common cases, but
2090          * _not_ for functional access control.
2091          *
2092          * May provide false positives, but should never provide a false negative.
2093          *
2094          * @param string $action Action that permission needs to be checked for
2095          * @param User|null $user User to check (since 1.19); $wgUser will be used if not provided.
2096          * @return bool
2097          */
2098         public function quickUserCan( $action, $user = null ) {
2099                 return $this->userCan( $action, $user, false );
2100         }
2101
2102         /**
2103          * Can $user perform $action on this page?
2104          *
2105          * @param string $action Action that permission needs to be checked for
2106          * @param User|null $user User to check (since 1.19); $wgUser will be used if not
2107          *   provided.
2108          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2109          * @return bool
2110          */
2111         public function userCan( $action, $user = null, $rigor = 'secure' ) {
2112                 if ( !$user instanceof User ) {
2113                         global $wgUser;
2114                         $user = $wgUser;
2115                 }
2116
2117                 return !count( $this->getUserPermissionsErrorsInternal( $action, $user, $rigor, true ) );
2118         }
2119
2120         /**
2121          * Can $user perform $action on this page?
2122          *
2123          * @todo FIXME: This *does not* check throttles (User::pingLimiter()).
2124          *
2125          * @param string $action Action that permission needs to be checked for
2126          * @param User $user User to check
2127          * @param string $rigor One of (quick,full,secure)
2128          *   - quick  : does cheap permission checks from replica DBs (usable for GUI creation)
2129          *   - full   : does cheap and expensive checks possibly from a replica DB
2130          *   - secure : does cheap and expensive checks, using the master as needed
2131          * @param array $ignoreErrors Array of Strings Set this to a list of message keys
2132          *   whose corresponding errors may be ignored.
2133          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
2134          */
2135         public function getUserPermissionsErrors(
2136                 $action, $user, $rigor = 'secure', $ignoreErrors = []
2137         ) {
2138                 $errors = $this->getUserPermissionsErrorsInternal( $action, $user, $rigor );
2139
2140                 // Remove the errors being ignored.
2141                 foreach ( $errors as $index => $error ) {
2142                         $errKey = is_array( $error ) ? $error[0] : $error;
2143
2144                         if ( in_array( $errKey, $ignoreErrors ) ) {
2145                                 unset( $errors[$index] );
2146                         }
2147                         if ( $errKey instanceof MessageSpecifier && in_array( $errKey->getKey(), $ignoreErrors ) ) {
2148                                 unset( $errors[$index] );
2149                         }
2150                 }
2151
2152                 return $errors;
2153         }
2154
2155         /**
2156          * Permissions checks that fail most often, and which are easiest to test.
2157          *
2158          * @param string $action The action to check
2159          * @param User $user User to check
2160          * @param array $errors List of current errors
2161          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2162          * @param bool $short Short circuit on first error
2163          *
2164          * @return array List of errors
2165          */
2166         private function checkQuickPermissions( $action, $user, $errors, $rigor, $short ) {
2167                 if ( !Hooks::run( 'TitleQuickPermissions',
2168                         [ $this, $user, $action, &$errors, ( $rigor !== 'quick' ), $short ] )
2169                 ) {
2170                         return $errors;
2171                 }
2172
2173                 if ( $action == 'create' ) {
2174                         if (
2175                                 ( $this->isTalkPage() && !$user->isAllowed( 'createtalk' ) ) ||
2176                                 ( !$this->isTalkPage() && !$user->isAllowed( 'createpage' ) )
2177                         ) {
2178                                 $errors[] = $user->isAnon() ? [ 'nocreatetext' ] : [ 'nocreate-loggedin' ];
2179                         }
2180                 } elseif ( $action == 'move' ) {
2181                         if ( !$user->isAllowed( 'move-rootuserpages' )
2182                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
2183                                 // Show user page-specific message only if the user can move other pages
2184                                 $errors[] = [ 'cant-move-user-page' ];
2185                         }
2186
2187                         // Check if user is allowed to move files if it's a file
2188                         if ( $this->mNamespace == NS_FILE && !$user->isAllowed( 'movefile' ) ) {
2189                                 $errors[] = [ 'movenotallowedfile' ];
2190                         }
2191
2192                         // Check if user is allowed to move category pages if it's a category page
2193                         if ( $this->mNamespace == NS_CATEGORY && !$user->isAllowed( 'move-categorypages' ) ) {
2194                                 $errors[] = [ 'cant-move-category-page' ];
2195                         }
2196
2197                         if ( !$user->isAllowed( 'move' ) ) {
2198                                 // User can't move anything
2199                                 $userCanMove = User::groupHasPermission( 'user', 'move' );
2200                                 $autoconfirmedCanMove = User::groupHasPermission( 'autoconfirmed', 'move' );
2201                                 if ( $user->isAnon() && ( $userCanMove || $autoconfirmedCanMove ) ) {
2202                                         // custom message if logged-in users without any special rights can move
2203                                         $errors[] = [ 'movenologintext' ];
2204                                 } else {
2205                                         $errors[] = [ 'movenotallowed' ];
2206                                 }
2207                         }
2208                 } elseif ( $action == 'move-target' ) {
2209                         if ( !$user->isAllowed( 'move' ) ) {
2210                                 // User can't move anything
2211                                 $errors[] = [ 'movenotallowed' ];
2212                         } elseif ( !$user->isAllowed( 'move-rootuserpages' )
2213                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
2214                                 // Show user page-specific message only if the user can move other pages
2215                                 $errors[] = [ 'cant-move-to-user-page' ];
2216                         } elseif ( !$user->isAllowed( 'move-categorypages' )
2217                                         && $this->mNamespace == NS_CATEGORY ) {
2218                                 // Show category page-specific message only if the user can move other pages
2219                                 $errors[] = [ 'cant-move-to-category-page' ];
2220                         }
2221                 } elseif ( !$user->isAllowed( $action ) ) {
2222                         $errors[] = $this->missingPermissionError( $action, $short );
2223                 }
2224
2225                 return $errors;
2226         }
2227
2228         /**
2229          * Add the resulting error code to the errors array
2230          *
2231          * @param array $errors List of current errors
2232          * @param array $result Result of errors
2233          *
2234          * @return array List of errors
2235          */
2236         private function resultToError( $errors, $result ) {
2237                 if ( is_array( $result ) && count( $result ) && !is_array( $result[0] ) ) {
2238                         // A single array representing an error
2239                         $errors[] = $result;
2240                 } elseif ( is_array( $result ) && is_array( $result[0] ) ) {
2241                         // A nested array representing multiple errors
2242                         $errors = array_merge( $errors, $result );
2243                 } elseif ( $result !== '' && is_string( $result ) ) {
2244                         // A string representing a message-id
2245                         $errors[] = [ $result ];
2246                 } elseif ( $result instanceof MessageSpecifier ) {
2247                         // A message specifier representing an error
2248                         $errors[] = [ $result ];
2249                 } elseif ( $result === false ) {
2250                         // a generic "We don't want them to do that"
2251                         $errors[] = [ 'badaccess-group0' ];
2252                 }
2253                 return $errors;
2254         }
2255
2256         /**
2257          * Check various permission hooks
2258          *
2259          * @param string $action The action to check
2260          * @param User $user User to check
2261          * @param array $errors List of current errors
2262          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2263          * @param bool $short Short circuit on first error
2264          *
2265          * @return array List of errors
2266          */
2267         private function checkPermissionHooks( $action, $user, $errors, $rigor, $short ) {
2268                 // Use getUserPermissionsErrors instead
2269                 $result = '';
2270                 // Avoid PHP 7.1 warning from passing $this by reference
2271                 $titleRef = $this;
2272                 if ( !Hooks::run( 'userCan', [ &$titleRef, &$user, $action, &$result ] ) ) {
2273                         return $result ? [] : [ [ 'badaccess-group0' ] ];
2274                 }
2275                 // Check getUserPermissionsErrors hook
2276                 // Avoid PHP 7.1 warning from passing $this by reference
2277                 $titleRef = $this;
2278                 if ( !Hooks::run( 'getUserPermissionsErrors', [ &$titleRef, &$user, $action, &$result ] ) ) {
2279                         $errors = $this->resultToError( $errors, $result );
2280                 }
2281                 // Check getUserPermissionsErrorsExpensive hook
2282                 if (
2283                         $rigor !== 'quick'
2284                         && !( $short && count( $errors ) > 0 )
2285                         && !Hooks::run( 'getUserPermissionsErrorsExpensive', [ &$titleRef, &$user, $action, &$result ] )
2286                 ) {
2287                         $errors = $this->resultToError( $errors, $result );
2288                 }
2289
2290                 return $errors;
2291         }
2292
2293         /**
2294          * Check permissions on special pages & namespaces
2295          *
2296          * @param string $action The action to check
2297          * @param User $user User to check
2298          * @param array $errors List of current errors
2299          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2300          * @param bool $short Short circuit on first error
2301          *
2302          * @return array List of errors
2303          */
2304         private function checkSpecialsAndNSPermissions( $action, $user, $errors, $rigor, $short ) {
2305                 # Only 'createaccount' can be performed on special pages,
2306                 # which don't actually exist in the DB.
2307                 if ( $this->isSpecialPage() && $action !== 'createaccount' ) {
2308                         $errors[] = [ 'ns-specialprotected' ];
2309                 }
2310
2311                 # Check $wgNamespaceProtection for restricted namespaces
2312                 if ( $this->isNamespaceProtected( $user ) ) {
2313                         $ns = $this->mNamespace == NS_MAIN ?
2314                                 wfMessage( 'nstab-main' )->text() : $this->getNsText();
2315                         $errors[] = $this->mNamespace == NS_MEDIAWIKI ?
2316                                 [ 'protectedinterface', $action ] : [ 'namespaceprotected', $ns, $action ];
2317                 }
2318
2319                 return $errors;
2320         }
2321
2322         /**
2323          * Check sitewide CSS/JSON/JS permissions
2324          *
2325          * @param string $action The action to check
2326          * @param User $user User to check
2327          * @param array $errors List of current errors
2328          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2329          * @param bool $short Short circuit on first error
2330          *
2331          * @return array List of errors
2332          */
2333         private function checkSiteConfigPermissions( $action, $user, $errors, $rigor, $short ) {
2334                 if ( $action != 'patrol' ) {
2335                         $error = null;
2336                         // Sitewide CSS/JSON/JS changes, like all NS_MEDIAWIKI changes, also require the
2337                         // editinterface right. That's implemented as a restriction so no check needed here.
2338                         if ( $this->isSiteCssConfigPage() && !$user->isAllowed( 'editsitecss' ) ) {
2339                                 $error = [ 'sitecssprotected', $action ];
2340                         } elseif ( $this->isSiteJsonConfigPage() && !$user->isAllowed( 'editsitejson' ) ) {
2341                                 $error = [ 'sitejsonprotected', $action ];
2342                         } elseif ( $this->isSiteJsConfigPage() && !$user->isAllowed( 'editsitejs' ) ) {
2343                                 $error = [ 'sitejsprotected', $action ];
2344                         } elseif ( $this->isRawHtmlMessage() ) {
2345                                 // Raw HTML can be used to deploy CSS or JS so require rights for both.
2346                                 if ( !$user->isAllowed( 'editsitejs' ) ) {
2347                                         $error = [ 'sitejsprotected', $action ];
2348                                 } elseif ( !$user->isAllowed( 'editsitecss' ) ) {
2349                                         $error = [ 'sitecssprotected', $action ];
2350                                 }
2351                         }
2352
2353                         if ( $error ) {
2354                                 if ( $user->isAllowed( 'editinterface' ) ) {
2355                                         // Most users / site admins will probably find out about the new, more restrictive
2356                                         // permissions by failing to edit something. Give them more info.
2357                                         // TODO remove this a few release cycles after 1.32
2358                                         $error = [ 'interfaceadmin-info', wfMessage( $error[0], $error[1] ) ];
2359                                 }
2360                                 $errors[] = $error;
2361                         }
2362                 }
2363
2364                 return $errors;
2365         }
2366
2367         /**
2368          * Check CSS/JSON/JS sub-page permissions
2369          *
2370          * @param string $action The action to check
2371          * @param User $user User to check
2372          * @param array $errors List of current errors
2373          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2374          * @param bool $short Short circuit on first error
2375          *
2376          * @return array List of errors
2377          */
2378         private function checkUserConfigPermissions( $action, $user, $errors, $rigor, $short ) {
2379                 # Protect css/json/js subpages of user pages
2380                 # XXX: this might be better using restrictions
2381
2382                 if ( $action === 'patrol' ) {
2383                         return $errors;
2384                 }
2385
2386                 if ( preg_match( '/^' . preg_quote( $user->getName(), '/' ) . '\//', $this->mTextform ) ) {
2387                         // Users need editmyuser* to edit their own CSS/JSON/JS subpages.
2388                         if (
2389                                 $this->isUserCssConfigPage()
2390                                 && !$user->isAllowedAny( 'editmyusercss', 'editusercss' )
2391                         ) {
2392                                 $errors[] = [ 'mycustomcssprotected', $action ];
2393                         } elseif (
2394                                 $this->isUserJsonConfigPage()
2395                                 && !$user->isAllowedAny( 'editmyuserjson', 'edituserjson' )
2396                         ) {
2397                                 $errors[] = [ 'mycustomjsonprotected', $action ];
2398                         } elseif (
2399                                 $this->isUserJsConfigPage()
2400                                 && !$user->isAllowedAny( 'editmyuserjs', 'edituserjs' )
2401                         ) {
2402                                 $errors[] = [ 'mycustomjsprotected', $action ];
2403                         }
2404                 } else {
2405                         // Users need editmyuser* to edit their own CSS/JSON/JS subpages, except for
2406                         // deletion/suppression which cannot be used for attacks and we want to avoid the
2407                         // situation where an unprivileged user can post abusive content on their subpages
2408                         // and only very highly privileged users could remove it.
2409                         if ( !in_array( $action, [ 'delete', 'deleterevision', 'suppressrevision' ], true ) ) {
2410                                 if (
2411                                         $this->isUserCssConfigPage()
2412                                         && !$user->isAllowed( 'editusercss' )
2413                                 ) {
2414                                         $errors[] = [ 'customcssprotected', $action ];
2415                                 } elseif (
2416                                         $this->isUserJsonConfigPage()
2417                                         && !$user->isAllowed( 'edituserjson' )
2418                                 ) {
2419                                         $errors[] = [ 'customjsonprotected', $action ];
2420                                 } elseif (
2421                                         $this->isUserJsConfigPage()
2422                                         && !$user->isAllowed( 'edituserjs' )
2423                                 ) {
2424                                         $errors[] = [ 'customjsprotected', $action ];
2425                                 }
2426                         }
2427                 }
2428
2429                 return $errors;
2430         }
2431
2432         /**
2433          * Check against page_restrictions table requirements on this
2434          * page. The user must possess all required rights for this
2435          * action.
2436          *
2437          * @param string $action The action to check
2438          * @param User $user User to check
2439          * @param array $errors List of current errors
2440          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2441          * @param bool $short Short circuit on first error
2442          *
2443          * @return array List of errors
2444          */
2445         private function checkPageRestrictions( $action, $user, $errors, $rigor, $short ) {
2446                 foreach ( $this->getRestrictions( $action ) as $right ) {
2447                         // Backwards compatibility, rewrite sysop -> editprotected
2448                         if ( $right == 'sysop' ) {
2449                                 $right = 'editprotected';
2450                         }
2451                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2452                         if ( $right == 'autoconfirmed' ) {
2453                                 $right = 'editsemiprotected';
2454                         }
2455                         if ( $right == '' ) {
2456                                 continue;
2457                         }
2458                         if ( !$user->isAllowed( $right ) ) {
2459                                 $errors[] = [ 'protectedpagetext', $right, $action ];
2460                         } elseif ( $this->mCascadeRestriction && !$user->isAllowed( 'protect' ) ) {
2461                                 $errors[] = [ 'protectedpagetext', 'protect', $action ];
2462                         }
2463                 }
2464
2465                 return $errors;
2466         }
2467
2468         /**
2469          * Check restrictions on cascading pages.
2470          *
2471          * @param string $action The action to check
2472          * @param User $user User to check
2473          * @param array $errors List of current errors
2474          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2475          * @param bool $short Short circuit on first error
2476          *
2477          * @return array List of errors
2478          */
2479         private function checkCascadingSourcesRestrictions( $action, $user, $errors, $rigor, $short ) {
2480                 if ( $rigor !== 'quick' && !$this->isUserConfigPage() ) {
2481                         # We /could/ use the protection level on the source page, but it's
2482                         # fairly ugly as we have to establish a precedence hierarchy for pages
2483                         # included by multiple cascade-protected pages. So just restrict
2484                         # it to people with 'protect' permission, as they could remove the
2485                         # protection anyway.
2486                         list( $cascadingSources, $restrictions ) = $this->getCascadeProtectionSources();
2487                         # Cascading protection depends on more than this page...
2488                         # Several cascading protected pages may include this page...
2489                         # Check each cascading level
2490                         # This is only for protection restrictions, not for all actions
2491                         if ( isset( $restrictions[$action] ) ) {
2492                                 foreach ( $restrictions[$action] as $right ) {
2493                                         // Backwards compatibility, rewrite sysop -> editprotected
2494                                         if ( $right == 'sysop' ) {
2495                                                 $right = 'editprotected';
2496                                         }
2497                                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2498                                         if ( $right == 'autoconfirmed' ) {
2499                                                 $right = 'editsemiprotected';
2500                                         }
2501                                         if ( $right != '' && !$user->isAllowedAll( 'protect', $right ) ) {
2502                                                 $pages = '';
2503                                                 foreach ( $cascadingSources as $page ) {
2504                                                         $pages .= '* [[:' . $page->getPrefixedText() . "]]\n";
2505                                                 }
2506                                                 $errors[] = [ 'cascadeprotected', count( $cascadingSources ), $pages, $action ];
2507                                         }
2508                                 }
2509                         }
2510                 }
2511
2512                 return $errors;
2513         }
2514
2515         /**
2516          * Check action permissions not already checked in checkQuickPermissions
2517          *
2518          * @param string $action The action to check
2519          * @param User $user User to check
2520          * @param array $errors List of current errors
2521          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2522          * @param bool $short Short circuit on first error
2523          *
2524          * @return array List of errors
2525          */
2526         private function checkActionPermissions( $action, $user, $errors, $rigor, $short ) {
2527                 global $wgDeleteRevisionsLimit, $wgLang;
2528
2529                 if ( $action == 'protect' ) {
2530                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit', $user, $rigor, true ) ) ) {
2531                                 // If they can't edit, they shouldn't protect.
2532                                 $errors[] = [ 'protect-cantedit' ];
2533                         }
2534                 } elseif ( $action == 'create' ) {
2535                         $title_protection = $this->getTitleProtection();
2536                         if ( $title_protection ) {
2537                                 if ( $title_protection['permission'] == ''
2538                                         || !$user->isAllowed( $title_protection['permission'] )
2539                                 ) {
2540                                         $errors[] = [
2541                                                 'titleprotected',
2542                                                 User::whoIs( $title_protection['user'] ),
2543                                                 $title_protection['reason']
2544                                         ];
2545                                 }
2546                         }
2547                 } elseif ( $action == 'move' ) {
2548                         // Check for immobile pages
2549                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2550                                 // Specific message for this case
2551                                 $errors[] = [ 'immobile-source-namespace', $this->getNsText() ];
2552                         } elseif ( !$this->isMovable() ) {
2553                                 // Less specific message for rarer cases
2554                                 $errors[] = [ 'immobile-source-page' ];
2555                         }
2556                 } elseif ( $action == 'move-target' ) {
2557                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2558                                 $errors[] = [ 'immobile-target-namespace', $this->getNsText() ];
2559                         } elseif ( !$this->isMovable() ) {
2560                                 $errors[] = [ 'immobile-target-page' ];
2561                         }
2562                 } elseif ( $action == 'delete' ) {
2563                         $tempErrors = $this->checkPageRestrictions( 'edit', $user, [], $rigor, true );
2564                         if ( !$tempErrors ) {
2565                                 $tempErrors = $this->checkCascadingSourcesRestrictions( 'edit',
2566                                         $user, $tempErrors, $rigor, true );
2567                         }
2568                         if ( $tempErrors ) {
2569                                 // If protection keeps them from editing, they shouldn't be able to delete.
2570                                 $errors[] = [ 'deleteprotected' ];
2571                         }
2572                         if ( $rigor !== 'quick' && $wgDeleteRevisionsLimit
2573                                 && !$this->userCan( 'bigdelete', $user ) && $this->isBigDeletion()
2574                         ) {
2575                                 $errors[] = [ 'delete-toobig', $wgLang->formatNum( $wgDeleteRevisionsLimit ) ];
2576                         }
2577                 } elseif ( $action === 'undelete' ) {
2578                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit', $user, $rigor, true ) ) ) {
2579                                 // Undeleting implies editing
2580                                 $errors[] = [ 'undelete-cantedit' ];
2581                         }
2582                         if ( !$this->exists()
2583                                 && count( $this->getUserPermissionsErrorsInternal( 'create', $user, $rigor, true ) )
2584                         ) {
2585                                 // Undeleting where nothing currently exists implies creating
2586                                 $errors[] = [ 'undelete-cantcreate' ];
2587                         }
2588                 }
2589                 return $errors;
2590         }
2591
2592         /**
2593          * Check that the user isn't blocked from editing.
2594          *
2595          * @param string $action The action to check
2596          * @param User $user User to check
2597          * @param array $errors List of current errors
2598          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2599          * @param bool $short Short circuit on first error
2600          *
2601          * @return array List of errors
2602          */
2603         private function checkUserBlock( $action, $user, $errors, $rigor, $short ) {
2604                 global $wgEmailConfirmToEdit, $wgBlockDisablesLogin;
2605                 // Account creation blocks handled at userlogin.
2606                 // Unblocking handled in SpecialUnblock
2607                 if ( $rigor === 'quick' || in_array( $action, [ 'createaccount', 'unblock' ] ) ) {
2608                         return $errors;
2609                 }
2610
2611                 // Optimize for a very common case
2612                 if ( $action === 'read' && !$wgBlockDisablesLogin ) {
2613                         return $errors;
2614                 }
2615
2616                 if ( $wgEmailConfirmToEdit
2617                         && !$user->isEmailConfirmed()
2618                         && $action === 'edit'
2619                 ) {
2620                         $errors[] = [ 'confirmedittext' ];
2621                 }
2622
2623                 $useReplica = ( $rigor !== 'secure' );
2624                 $block = $user->getBlock( $useReplica );
2625
2626                 // If the user does not have a block, or the block they do have explicitly
2627                 // allows the action (like "read" or "upload").
2628                 if ( !$block || $block->appliesToRight( $action ) === false ) {
2629                         return $errors;
2630                 }
2631
2632                 // Determine if the user is blocked from this action on this page.
2633                 // What gets passed into this method is a user right, not an action name.
2634                 // There is no way to instantiate an action by restriction. However, this
2635                 // will get the action where the restriction is the same. This may result
2636                 // in actions being blocked that shouldn't be.
2637                 $actionObj = null;
2638                 if ( Action::exists( $action ) ) {
2639                         // Clone the title to prevent mutations to this object which is done
2640                         // by Title::loadFromRow() in WikiPage::loadFromRow().
2641                         $page = WikiPage::factory( clone $this );
2642                         // Creating an action will perform several database queries to ensure that
2643                         // the action has not been overridden by the content type.
2644                         // @todo FIXME: Pass the relevant context into this function.
2645                         $actionObj = Action::factory( $action, $page, RequestContext::getMain() );
2646                         // Ensure that the retrieved action matches the restriction.
2647                         if ( $actionObj && $actionObj->getRestriction() !== $action ) {
2648                                 $actionObj = null;
2649                         }
2650                 }
2651
2652                 // If no action object is returned, assume that the action requires unblock
2653                 // which is the default.
2654                 if ( !$actionObj || $actionObj->requiresUnblock() ) {
2655                         if ( $user->isBlockedFrom( $this, $useReplica ) ) {
2656                                 // @todo FIXME: Pass the relevant context into this function.
2657                                 $errors[] = $block->getPermissionsError( RequestContext::getMain() );
2658                         }
2659                 }
2660
2661                 return $errors;
2662         }
2663
2664         /**
2665          * Check that the user is allowed to read this page.
2666          *
2667          * @param string $action The action to check
2668          * @param User $user User to check
2669          * @param array $errors List of current errors
2670          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2671          * @param bool $short Short circuit on first error
2672          *
2673          * @return array List of errors
2674          */
2675         private function checkReadPermissions( $action, $user, $errors, $rigor, $short ) {
2676                 global $wgWhitelistRead, $wgWhitelistReadRegexp;
2677
2678                 $whitelisted = false;
2679                 if ( User::isEveryoneAllowed( 'read' ) ) {
2680                         # Shortcut for public wikis, allows skipping quite a bit of code
2681                         $whitelisted = true;
2682                 } elseif ( $user->isAllowed( 'read' ) ) {
2683                         # If the user is allowed to read pages, he is allowed to read all pages
2684                         $whitelisted = true;
2685                 } elseif ( $this->isSpecial( 'Userlogin' )
2686                         || $this->isSpecial( 'PasswordReset' )
2687                         || $this->isSpecial( 'Userlogout' )
2688                 ) {
2689                         # Always grant access to the login page.
2690                         # Even anons need to be able to log in.
2691                         $whitelisted = true;
2692                 } elseif ( is_array( $wgWhitelistRead ) && count( $wgWhitelistRead ) ) {
2693                         # Time to check the whitelist
2694                         # Only do these checks is there's something to check against
2695                         $name = $this->getPrefixedText();
2696                         $dbName = $this->getPrefixedDBkey();
2697
2698                         // Check for explicit whitelisting with and without underscores
2699                         if ( in_array( $name, $wgWhitelistRead, true ) || in_array( $dbName, $wgWhitelistRead, true ) ) {
2700                                 $whitelisted = true;
2701                         } elseif ( $this->mNamespace == NS_MAIN ) {
2702                                 # Old settings might have the title prefixed with
2703                                 # a colon for main-namespace pages
2704                                 if ( in_array( ':' . $name, $wgWhitelistRead ) ) {
2705                                         $whitelisted = true;
2706                                 }
2707                         } elseif ( $this->isSpecialPage() ) {
2708                                 # If it's a special page, ditch the subpage bit and check again
2709                                 $name = $this->mDbkeyform;
2710                                 list( $name, /* $subpage */ ) =
2711                                         MediaWikiServices::getInstance()->getSpecialPageFactory()->
2712                                                 resolveAlias( $name );
2713                                 if ( $name ) {
2714                                         $pure = SpecialPage::getTitleFor( $name )->getPrefixedText();
2715                                         if ( in_array( $pure, $wgWhitelistRead, true ) ) {
2716                                                 $whitelisted = true;
2717                                         }
2718                                 }
2719                         }
2720                 }
2721
2722                 if ( !$whitelisted && is_array( $wgWhitelistReadRegexp ) && !empty( $wgWhitelistReadRegexp ) ) {
2723                         $name = $this->getPrefixedText();
2724                         // Check for regex whitelisting
2725                         foreach ( $wgWhitelistReadRegexp as $listItem ) {
2726                                 if ( preg_match( $listItem, $name ) ) {
2727                                         $whitelisted = true;
2728                                         break;
2729                                 }
2730                         }
2731                 }
2732
2733                 if ( !$whitelisted ) {
2734                         # If the title is not whitelisted, give extensions a chance to do so...
2735                         Hooks::run( 'TitleReadWhitelist', [ $this, $user, &$whitelisted ] );
2736                         if ( !$whitelisted ) {
2737                                 $errors[] = $this->missingPermissionError( $action, $short );
2738                         }
2739                 }
2740
2741                 return $errors;
2742         }
2743
2744         /**
2745          * Get a description array when the user doesn't have the right to perform
2746          * $action (i.e. when User::isAllowed() returns false)
2747          *
2748          * @param string $action The action to check
2749          * @param bool $short Short circuit on first error
2750          * @return array Array containing an error message key and any parameters
2751          */
2752         private function missingPermissionError( $action, $short ) {
2753                 // We avoid expensive display logic for quickUserCan's and such
2754                 if ( $short ) {
2755                         return [ 'badaccess-group0' ];
2756                 }
2757
2758                 return User::newFatalPermissionDeniedStatus( $action )->getErrorsArray()[0];
2759         }
2760
2761         /**
2762          * Can $user perform $action on this page? This is an internal function,
2763          * with multiple levels of checks depending on performance needs; see $rigor below.
2764          * It does not check wfReadOnly().
2765          *
2766          * @param string $action Action that permission needs to be checked for
2767          * @param User $user User to check
2768          * @param string $rigor One of (quick,full,secure)
2769          *   - quick  : does cheap permission checks from replica DBs (usable for GUI creation)
2770          *   - full   : does cheap and expensive checks possibly from a replica DB
2771          *   - secure : does cheap and expensive checks, using the master as needed
2772          * @param bool $short Set this to true to stop after the first permission error.
2773          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
2774          */
2775         protected function getUserPermissionsErrorsInternal(
2776                 $action, $user, $rigor = 'secure', $short = false
2777         ) {
2778                 if ( $rigor === true ) {
2779                         $rigor = 'secure'; // b/c
2780                 } elseif ( $rigor === false ) {
2781                         $rigor = 'quick'; // b/c
2782                 } elseif ( !in_array( $rigor, [ 'quick', 'full', 'secure' ] ) ) {
2783                         throw new Exception( "Invalid rigor parameter '$rigor'." );
2784                 }
2785
2786                 # Read has special handling
2787                 if ( $action == 'read' ) {
2788                         $checks = [
2789                                 'checkPermissionHooks',
2790                                 'checkReadPermissions',
2791                                 'checkUserBlock', // for wgBlockDisablesLogin
2792                         ];
2793                 # Don't call checkSpecialsAndNSPermissions, checkSiteConfigPermissions
2794                 # or checkUserConfigPermissions here as it will lead to duplicate
2795                 # error messages. This is okay to do since anywhere that checks for
2796                 # create will also check for edit, and those checks are called for edit.
2797                 } elseif ( $action == 'create' ) {
2798                         $checks = [
2799                                 'checkQuickPermissions',
2800                                 'checkPermissionHooks',
2801                                 'checkPageRestrictions',
2802                                 'checkCascadingSourcesRestrictions',
2803                                 'checkActionPermissions',
2804                                 'checkUserBlock'
2805                         ];
2806                 } else {
2807                         $checks = [
2808                                 'checkQuickPermissions',
2809                                 'checkPermissionHooks',
2810                                 'checkSpecialsAndNSPermissions',
2811                                 'checkSiteConfigPermissions',
2812                                 'checkUserConfigPermissions',
2813                                 'checkPageRestrictions',
2814                                 'checkCascadingSourcesRestrictions',
2815                                 'checkActionPermissions',
2816                                 'checkUserBlock'
2817                         ];
2818                 }
2819
2820                 $errors = [];
2821                 foreach ( $checks as $method ) {
2822                         $errors = $this->$method( $action, $user, $errors, $rigor, $short );
2823
2824                         if ( $short && $errors !== [] ) {
2825                                 break;
2826                         }
2827                 }
2828
2829                 return $errors;
2830         }
2831
2832         /**
2833          * Get a filtered list of all restriction types supported by this wiki.
2834          * @param bool $exists True to get all restriction types that apply to
2835          * titles that do exist, False for all restriction types that apply to
2836          * titles that do not exist
2837          * @return array
2838          */
2839         public static function getFilteredRestrictionTypes( $exists = true ) {
2840                 global $wgRestrictionTypes;
2841                 $types = $wgRestrictionTypes;
2842                 if ( $exists ) {
2843                         # Remove the create restriction for existing titles
2844                         $types = array_diff( $types, [ 'create' ] );
2845                 } else {
2846                         # Only the create and upload restrictions apply to non-existing titles
2847                         $types = array_intersect( $types, [ 'create', 'upload' ] );
2848                 }
2849                 return $types;
2850         }
2851
2852         /**
2853          * Returns restriction types for the current Title
2854          *
2855          * @return array Applicable restriction types
2856          */
2857         public function getRestrictionTypes() {
2858                 if ( $this->isSpecialPage() ) {
2859                         return [];
2860                 }
2861
2862                 $types = self::getFilteredRestrictionTypes( $this->exists() );
2863
2864                 if ( $this->mNamespace != NS_FILE ) {
2865                         # Remove the upload restriction for non-file titles
2866                         $types = array_diff( $types, [ 'upload' ] );
2867                 }
2868
2869                 Hooks::run( 'TitleGetRestrictionTypes', [ $this, &$types ] );
2870
2871                 wfDebug( __METHOD__ . ': applicable restrictions to [[' .
2872                         $this->getPrefixedText() . ']] are {' . implode( ',', $types ) . "}\n" );
2873
2874                 return $types;
2875         }
2876
2877         /**
2878          * Is this title subject to title protection?
2879          * Title protection is the one applied against creation of such title.
2880          *
2881          * @return array|bool An associative array representing any existent title
2882          *   protection, or false if there's none.
2883          */
2884         public function getTitleProtection() {
2885                 $protection = $this->getTitleProtectionInternal();
2886                 if ( $protection ) {
2887                         if ( $protection['permission'] == 'sysop' ) {
2888                                 $protection['permission'] = 'editprotected'; // B/C
2889                         }
2890                         if ( $protection['permission'] == 'autoconfirmed' ) {
2891                                 $protection['permission'] = 'editsemiprotected'; // B/C
2892                         }
2893                 }
2894                 return $protection;
2895         }
2896
2897         /**
2898          * Fetch title protection settings
2899          *
2900          * To work correctly, $this->loadRestrictions() needs to have access to the
2901          * actual protections in the database without munging 'sysop' =>
2902          * 'editprotected' and 'autoconfirmed' => 'editsemiprotected'. Other
2903          * callers probably want $this->getTitleProtection() instead.
2904          *
2905          * @return array|bool
2906          */
2907         protected function getTitleProtectionInternal() {
2908                 // Can't protect pages in special namespaces
2909                 if ( $this->mNamespace < 0 ) {
2910                         return false;
2911                 }
2912
2913                 // Can't protect pages that exist.
2914                 if ( $this->exists() ) {
2915                         return false;
2916                 }
2917
2918                 if ( $this->mTitleProtection === null ) {
2919                         $dbr = wfGetDB( DB_REPLICA );
2920                         $commentStore = CommentStore::getStore();
2921                         $commentQuery = $commentStore->getJoin( 'pt_reason' );
2922                         $res = $dbr->select(
2923                                 [ 'protected_titles' ] + $commentQuery['tables'],
2924                                 [
2925                                         'user' => 'pt_user',
2926                                         'expiry' => 'pt_expiry',
2927                                         'permission' => 'pt_create_perm'
2928                                 ] + $commentQuery['fields'],
2929                                 [ 'pt_namespace' => $this->mNamespace, 'pt_title' => $this->mDbkeyform ],
2930                                 __METHOD__,
2931                                 [],
2932                                 $commentQuery['joins']
2933                         );
2934
2935                         // fetchRow returns false if there are no rows.
2936                         $row = $dbr->fetchRow( $res );
2937                         if ( $row ) {
2938                                 $this->mTitleProtection = [
2939                                         'user' => $row['user'],
2940                                         'expiry' => $dbr->decodeExpiry( $row['expiry'] ),
2941                                         'permission' => $row['permission'],
2942                                         'reason' => $commentStore->getComment( 'pt_reason', $row )->text,
2943                                 ];
2944                         } else {
2945                                 $this->mTitleProtection = false;
2946                         }
2947                 }
2948                 return $this->mTitleProtection;
2949         }
2950
2951         /**
2952          * Remove any title protection due to page existing
2953          */
2954         public function deleteTitleProtection() {
2955                 $dbw = wfGetDB( DB_MASTER );
2956
2957                 $dbw->delete(
2958                         'protected_titles',
2959                         [ 'pt_namespace' => $this->mNamespace, 'pt_title' => $this->mDbkeyform ],
2960                         __METHOD__
2961                 );
2962                 $this->mTitleProtection = false;
2963         }
2964
2965         /**
2966          * Is this page "semi-protected" - the *only* protection levels are listed
2967          * in $wgSemiprotectedRestrictionLevels?
2968          *
2969          * @param string $action Action to check (default: edit)
2970          * @return bool
2971          */
2972         public function isSemiProtected( $action = 'edit' ) {
2973                 global $wgSemiprotectedRestrictionLevels;
2974
2975                 $restrictions = $this->getRestrictions( $action );
2976                 $semi = $wgSemiprotectedRestrictionLevels;
2977                 if ( !$restrictions || !$semi ) {
2978                         // Not protected, or all protection is full protection
2979                         return false;
2980                 }
2981
2982                 // Remap autoconfirmed to editsemiprotected for BC
2983                 foreach ( array_keys( $semi, 'autoconfirmed' ) as $key ) {
2984                         $semi[$key] = 'editsemiprotected';
2985                 }
2986                 foreach ( array_keys( $restrictions, 'autoconfirmed' ) as $key ) {
2987                         $restrictions[$key] = 'editsemiprotected';
2988                 }
2989
2990                 return !array_diff( $restrictions, $semi );
2991         }
2992
2993         /**
2994          * Does the title correspond to a protected article?
2995          *
2996          * @param string $action The action the page is protected from,
2997          * by default checks all actions.
2998          * @return bool
2999          */
3000         public function isProtected( $action = '' ) {
3001                 global $wgRestrictionLevels;
3002
3003                 $restrictionTypes = $this->getRestrictionTypes();
3004
3005                 # Special pages have inherent protection
3006                 if ( $this->isSpecialPage() ) {
3007                         return true;
3008                 }
3009
3010                 # Check regular protection levels
3011                 foreach ( $restrictionTypes as $type ) {
3012                         if ( $action == $type || $action == '' ) {
3013                                 $r = $this->getRestrictions( $type );
3014                                 foreach ( $wgRestrictionLevels as $level ) {
3015                                         if ( in_array( $level, $r ) && $level != '' ) {
3016                                                 return true;
3017                                         }
3018                                 }
3019                         }
3020                 }
3021
3022                 return false;
3023         }
3024
3025         /**
3026          * Determines if $user is unable to edit this page because it has been protected
3027          * by $wgNamespaceProtection.
3028          *
3029          * @param User $user User object to check permissions
3030          * @return bool
3031          */
3032         public function isNamespaceProtected( User $user ) {
3033                 global $wgNamespaceProtection;
3034
3035                 if ( isset( $wgNamespaceProtection[$this->mNamespace] ) ) {
3036                         foreach ( (array)$wgNamespaceProtection[$this->mNamespace] as $right ) {
3037                                 if ( $right != '' && !$user->isAllowed( $right ) ) {
3038                                         return true;
3039                                 }
3040                         }
3041                 }
3042                 return false;
3043         }
3044
3045         /**
3046          * Cascading protection: Return true if cascading restrictions apply to this page, false if not.
3047          *
3048          * @return bool If the page is subject to cascading restrictions.
3049          */
3050         public function isCascadeProtected() {
3051                 list( $sources, /* $restrictions */ ) = $this->getCascadeProtectionSources( false );
3052                 return ( $sources > 0 );
3053         }
3054
3055         /**
3056          * Determines whether cascading protection sources have already been loaded from
3057          * the database.
3058          *
3059          * @param bool $getPages True to check if the pages are loaded, or false to check
3060          * if the status is loaded.
3061          * @return bool Whether or not the specified information has been loaded
3062          * @since 1.23
3063          */
3064         public function areCascadeProtectionSourcesLoaded( $getPages = true ) {
3065                 return $getPages ? $this->mCascadeSources !== null : $this->mHasCascadingRestrictions !== null;
3066         }
3067
3068         /**
3069          * Cascading protection: Get the source of any cascading restrictions on this page.
3070          *
3071          * @param bool $getPages Whether or not to retrieve the actual pages
3072          *        that the restrictions have come from and the actual restrictions
3073          *        themselves.
3074          * @return array Two elements: First is an array of Title objects of the
3075          *        pages from which cascading restrictions have come, false for
3076          *        none, or true if such restrictions exist but $getPages was not
3077          *        set. Second is an array like that returned by
3078          *        Title::getAllRestrictions(), or an empty array if $getPages is
3079          *        false.
3080          */
3081         public function getCascadeProtectionSources( $getPages = true ) {
3082                 $pagerestrictions = [];
3083
3084                 if ( $this->mCascadeSources !== null && $getPages ) {
3085                         return [ $this->mCascadeSources, $this->mCascadingRestrictions ];
3086                 } elseif ( $this->mHasCascadingRestrictions !== null && !$getPages ) {
3087                         return [ $this->mHasCascadingRestrictions, $pagerestrictions ];
3088                 }
3089
3090                 $dbr = wfGetDB( DB_REPLICA );
3091
3092                 if ( $this->mNamespace == NS_FILE ) {
3093                         $tables = [ 'imagelinks', 'page_restrictions' ];
3094                         $where_clauses = [
3095                                 'il_to' => $this->mDbkeyform,
3096                                 'il_from=pr_page',
3097                                 'pr_cascade' => 1
3098                         ];
3099                 } else {
3100                         $tables = [ 'templatelinks', 'page_restrictions' ];
3101                         $where_clauses = [
3102                                 'tl_namespace' => $this->mNamespace,
3103                                 'tl_title' => $this->mDbkeyform,
3104                                 'tl_from=pr_page',
3105                                 'pr_cascade' => 1
3106                         ];
3107                 }
3108
3109                 if ( $getPages ) {
3110                         $cols = [ 'pr_page', 'page_namespace', 'page_title',
3111                                 'pr_expiry', 'pr_type', 'pr_level' ];
3112                         $where_clauses[] = 'page_id=pr_page';
3113                         $tables[] = 'page';
3114                 } else {
3115                         $cols = [ 'pr_expiry' ];
3116                 }
3117
3118                 $res = $dbr->select( $tables, $cols, $where_clauses, __METHOD__ );
3119
3120                 $sources = $getPages ? [] : false;
3121                 $now = wfTimestampNow();
3122
3123                 foreach ( $res as $row ) {
3124                         $expiry = $dbr->decodeExpiry( $row->pr_expiry );
3125                         if ( $expiry > $now ) {
3126                                 if ( $getPages ) {
3127                                         $page_id = $row->pr_page;
3128                                         $page_ns = $row->page_namespace;
3129                                         $page_title = $row->page_title;
3130                                         $sources[$page_id] = self::makeTitle( $page_ns, $page_title );
3131                                         # Add groups needed for each restriction type if its not already there
3132                                         # Make sure this restriction type still exists
3133
3134                                         if ( !isset( $pagerestrictions[$row->pr_type] ) ) {
3135                                                 $pagerestrictions[$row->pr_type] = [];
3136                                         }
3137
3138                                         if (
3139                                                 isset( $pagerestrictions[$row->pr_type] )
3140                                                 && !in_array( $row->pr_level, $pagerestrictions[$row->pr_type] )
3141                                         ) {
3142                                                 $pagerestrictions[$row->pr_type][] = $row->pr_level;
3143                                         }
3144                                 } else {
3145                                         $sources = true;
3146                                 }
3147                         }
3148                 }
3149
3150                 if ( $getPages ) {
3151                         $this->mCascadeSources = $sources;
3152                         $this->mCascadingRestrictions = $pagerestrictions;
3153                 } else {
3154                         $this->mHasCascadingRestrictions = $sources;
3155                 }
3156
3157                 return [ $sources, $pagerestrictions ];
3158         }
3159
3160         /**
3161          * Accessor for mRestrictionsLoaded
3162          *
3163          * @return bool Whether or not the page's restrictions have already been
3164          * loaded from the database
3165          * @since 1.23
3166          */
3167         public function areRestrictionsLoaded() {
3168                 return $this->mRestrictionsLoaded;
3169         }
3170
3171         /**
3172          * Accessor/initialisation for mRestrictions
3173          *
3174          * @param string $action Action that permission needs to be checked for
3175          * @return array Restriction levels needed to take the action. All levels are
3176          *     required. Note that restriction levels are normally user rights, but 'sysop'
3177          *     and 'autoconfirmed' are also allowed for backwards compatibility. These should
3178          *     be mapped to 'editprotected' and 'editsemiprotected' respectively.
3179          */
3180         public function getRestrictions( $action ) {
3181                 if ( !$this->mRestrictionsLoaded ) {
3182                         $this->loadRestrictions();
3183                 }
3184                 return $this->mRestrictions[$action] ?? [];
3185         }
3186
3187         /**
3188          * Accessor/initialisation for mRestrictions
3189          *
3190          * @return array Keys are actions, values are arrays as returned by
3191          *     Title::getRestrictions()
3192          * @since 1.23
3193          */
3194         public function getAllRestrictions() {
3195                 if ( !$this->mRestrictionsLoaded ) {
3196                         $this->loadRestrictions();
3197                 }
3198                 return $this->mRestrictions;
3199         }
3200
3201         /**
3202          * Get the expiry time for the restriction against a given action
3203          *
3204          * @param string $action
3205          * @return string|bool 14-char timestamp, or 'infinity' if the page is protected forever
3206          *     or not protected at all, or false if the action is not recognised.
3207          */
3208         public function getRestrictionExpiry( $action ) {
3209                 if ( !$this->mRestrictionsLoaded ) {
3210                         $this->loadRestrictions();
3211                 }
3212                 return $this->mRestrictionsExpiry[$action] ?? false;
3213         }
3214
3215         /**
3216          * Returns cascading restrictions for the current article
3217          *
3218          * @return bool
3219          */
3220         function areRestrictionsCascading() {
3221                 if ( !$this->mRestrictionsLoaded ) {
3222                         $this->loadRestrictions();
3223                 }
3224
3225                 return $this->mCascadeRestriction;
3226         }
3227
3228         /**
3229          * Compiles list of active page restrictions from both page table (pre 1.10)
3230          * and page_restrictions table for this existing page.
3231          * Public for usage by LiquidThreads.
3232          *
3233          * @param array $rows Array of db result objects
3234          * @param string|null $oldFashionedRestrictions Comma-separated set of permission keys
3235          * indicating who can move or edit the page from the page table, (pre 1.10) rows.
3236          * Edit and move sections are separated by a colon
3237          * Example: "edit=autoconfirmed,sysop:move=sysop"
3238          */
3239         public function loadRestrictionsFromRows( $rows, $oldFashionedRestrictions = null ) {
3240                 // This function will only read rows from a table that we migrated away
3241                 // from before adding READ_LATEST support to loadRestrictions, so we
3242                 // don't need to support reading from DB_MASTER here.
3243                 $dbr = wfGetDB( DB_REPLICA );
3244
3245                 $restrictionTypes = $this->getRestrictionTypes();
3246
3247                 foreach ( $restrictionTypes as $type ) {
3248                         $this->mRestrictions[$type] = [];
3249                         $this->mRestrictionsExpiry[$type] = 'infinity';
3250                 }
3251
3252                 $this->mCascadeRestriction = false;
3253
3254                 # Backwards-compatibility: also load the restrictions from the page record (old format).
3255                 if ( $oldFashionedRestrictions !== null ) {
3256                         $this->mOldRestrictions = $oldFashionedRestrictions;
3257                 }
3258
3259                 if ( $this->mOldRestrictions === false ) {
3260                         $linkCache = MediaWikiServices::getInstance()->getLinkCache();
3261                         $linkCache->addLinkObj( $this ); # in case we already had an article ID
3262                         $this->mOldRestrictions = $linkCache->getGoodLinkFieldObj( $this, 'restrictions' );
3263                 }
3264
3265                 if ( $this->mOldRestrictions != '' ) {
3266                         foreach ( explode( ':', trim( $this->mOldRestrictions ) ) as $restrict ) {
3267                                 $temp = explode( '=', trim( $restrict ) );
3268                                 if ( count( $temp ) == 1 ) {
3269                                         // old old format should be treated as edit/move restriction
3270                                         $this->mRestrictions['edit'] = explode( ',', trim( $temp[0] ) );
3271                                         $this->mRestrictions['move'] = explode( ',', trim( $temp[0] ) );
3272                                 } else {
3273                                         $restriction = trim( $temp[1] );
3274                                         if ( $restriction != '' ) { // some old entries are empty
3275                                                 $this->mRestrictions[$temp[0]] = explode( ',', $restriction );
3276                                         }
3277                                 }
3278                         }
3279                 }
3280
3281                 if ( count( $rows ) ) {
3282                         # Current system - load second to make them override.
3283                         $now = wfTimestampNow();
3284
3285                         # Cycle through all the restrictions.
3286                         foreach ( $rows as $row ) {
3287                                 // Don't take care of restrictions types that aren't allowed
3288                                 if ( !in_array( $row->pr_type, $restrictionTypes ) ) {
3289                                         continue;
3290                                 }
3291
3292                                 $expiry = $dbr->decodeExpiry( $row->pr_expiry );
3293
3294                                 // Only apply the restrictions if they haven't expired!
3295                                 if ( !$expiry || $expiry > $now ) {
3296                                         $this->mRestrictionsExpiry[$row->pr_type] = $expiry;
3297                                         $this->mRestrictions[$row->pr_type] = explode( ',', trim( $row->pr_level ) );
3298
3299                                         $this->mCascadeRestriction |= $row->pr_cascade;
3300                                 }
3301                         }
3302                 }
3303
3304                 $this->mRestrictionsLoaded = true;
3305         }
3306
3307         /**
3308          * Load restrictions from the page_restrictions table
3309          *
3310          * @param string|null $oldFashionedRestrictions Comma-separated set of permission keys
3311          * indicating who can move or edit the page from the page table, (pre 1.10) rows.
3312          * Edit and move sections are separated by a colon
3313          * Example: "edit=autoconfirmed,sysop:move=sysop"
3314          * @param int $flags A bit field. If self::READ_LATEST is set, skip replicas and read
3315          *  from the master DB.
3316          */
3317         public function loadRestrictions( $oldFashionedRestrictions = null, $flags = 0 ) {
3318                 $readLatest = DBAccessObjectUtils::hasFlags( $flags, self::READ_LATEST );
3319                 if ( $this->mRestrictionsLoaded && !$readLatest ) {
3320                         return;
3321                 }
3322
3323                 // TODO: should probably pass $flags into getArticleID, but it seems hacky
3324                 // to mix READ_LATEST and GAID_FOR_UPDATE, even if they have the same value.
3325                 // Maybe deprecate GAID_FOR_UPDATE now that we implement IDBAccessObject?
3326                 $id = $this->getArticleID();
3327                 if ( $id ) {
3328                         $fname = __METHOD__;
3329                         $loadRestrictionsFromDb = function ( Database $dbr ) use ( $fname, $id ) {
3330                                 return iterator_to_array(
3331                                         $dbr->select(
3332                                                 'page_restrictions',
3333                                                 [ 'pr_type', 'pr_expiry', 'pr_level', 'pr_cascade' ],
3334                                                 [ 'pr_page' => $id ],
3335                                                 $fname
3336                                         )
3337                                 );
3338                         };
3339
3340                         if ( $readLatest ) {
3341                                 $dbr = wfGetDB( DB_MASTER );
3342                                 $rows = $loadRestrictionsFromDb( $dbr );
3343                         } else {
3344                                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
3345                                 $rows = $cache->getWithSetCallback(
3346                                         // Page protections always leave a new null revision
3347                                         $cache->makeKey( 'page-restrictions', 'v1', $id, $this->getLatestRevID() ),
3348                                         $cache::TTL_DAY,
3349                                         function ( $curValue, &$ttl, array &$setOpts ) use ( $loadRestrictionsFromDb ) {
3350                                                 $dbr = wfGetDB( DB_REPLICA );
3351
3352                                                 $setOpts += Database::getCacheSetOptions( $dbr );
3353                                                 $lb = MediaWikiServices::getInstance()->getDBLoadBalancer();
3354                                                 if ( $lb->hasOrMadeRecentMasterChanges() ) {
3355                                                         // @TODO: cleanup Title cache and caller assumption mess in general
3356                                                         $ttl = WANObjectCache::TTL_UNCACHEABLE;
3357                                                 }
3358
3359                                                 return $loadRestrictionsFromDb( $dbr );
3360                                         }
3361                                 );
3362                         }
3363
3364                         $this->loadRestrictionsFromRows( $rows, $oldFashionedRestrictions );
3365                 } else {
3366                         $title_protection = $this->getTitleProtectionInternal();
3367
3368                         if ( $title_protection ) {
3369                                 $now = wfTimestampNow();
3370                                 $expiry = wfGetDB( DB_REPLICA )->decodeExpiry( $title_protection['expiry'] );
3371
3372                                 if ( !$expiry || $expiry > $now ) {
3373                                         // Apply the restrictions
3374                                         $this->mRestrictionsExpiry['create'] = $expiry;
3375                                         $this->mRestrictions['create'] =
3376                                                 explode( ',', trim( $title_protection['permission'] ) );
3377                                 } else { // Get rid of the old restrictions
3378                                         $this->mTitleProtection = false;
3379                                 }
3380                         } else {
3381                                 $this->mRestrictionsExpiry['create'] = 'infinity';
3382                         }
3383                         $this->mRestrictionsLoaded = true;
3384                 }
3385         }
3386
3387         /**
3388          * Flush the protection cache in this object and force reload from the database.
3389          * This is used when updating protection from WikiPage::doUpdateRestrictions().
3390          */
3391         public function flushRestrictions() {
3392                 $this->mRestrictionsLoaded = false;
3393                 $this->mTitleProtection = null;
3394         }
3395
3396         /**
3397          * Purge expired restrictions from the page_restrictions table
3398          *
3399          * This will purge no more than $wgUpdateRowsPerQuery page_restrictions rows
3400          */
3401         static function purgeExpiredRestrictions() {
3402                 if ( wfReadOnly() ) {
3403                         return;
3404                 }
3405
3406                 DeferredUpdates::addUpdate( new AtomicSectionUpdate(
3407                         wfGetDB( DB_MASTER ),
3408                         __METHOD__,
3409                         function ( IDatabase $dbw, $fname ) {
3410                                 $config = MediaWikiServices::getInstance()->getMainConfig();
3411                                 $ids = $dbw->selectFieldValues(
3412                                         'page_restrictions',
3413                                         'pr_id',
3414                                         [ 'pr_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ],
3415                                         $fname,
3416                                         [ 'LIMIT' => $config->get( 'UpdateRowsPerQuery' ) ] // T135470
3417                                 );
3418                                 if ( $ids ) {
3419                                         $dbw->delete( 'page_restrictions', [ 'pr_id' => $ids ], $fname );
3420                                 }
3421                         }
3422                 ) );
3423
3424                 DeferredUpdates::addUpdate( new AtomicSectionUpdate(
3425                         wfGetDB( DB_MASTER ),
3426                         __METHOD__,
3427                         function ( IDatabase $dbw, $fname ) {
3428                                 $dbw->delete(
3429                                         'protected_titles',
3430                                         [ 'pt_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ],
3431                                         $fname
3432                                 );
3433                         }
3434                 ) );
3435         }
3436
3437         /**
3438          * Does this have subpages?  (Warning, usually requires an extra DB query.)
3439          *
3440          * @return bool
3441          */
3442         public function hasSubpages() {
3443                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
3444                         # Duh
3445                         return false;
3446                 }
3447
3448                 # We dynamically add a member variable for the purpose of this method
3449                 # alone to cache the result.  There's no point in having it hanging
3450                 # around uninitialized in every Title object; therefore we only add it
3451                 # if needed and don't declare it statically.
3452                 if ( $this->mHasSubpages === null ) {
3453                         $this->mHasSubpages = false;
3454                         $subpages = $this->getSubpages( 1 );
3455                         if ( $subpages instanceof TitleArray ) {
3456                                 $this->mHasSubpages = (bool)$subpages->count();
3457                         }
3458                 }
3459
3460                 return $this->mHasSubpages;
3461         }
3462
3463         /**
3464          * Get all subpages of this page.
3465          *
3466          * @param int $limit Maximum number of subpages to fetch; -1 for no limit
3467          * @return TitleArray|array TitleArray, or empty array if this page's namespace
3468          *  doesn't allow subpages
3469          */
3470         public function getSubpages( $limit = -1 ) {
3471                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
3472                         return [];
3473                 }
3474
3475                 $dbr = wfGetDB( DB_REPLICA );
3476                 $conds['page_namespace'] = $this->mNamespace;
3477                 $conds[] = 'page_title ' . $dbr->buildLike( $this->mDbkeyform . '/', $dbr->anyString() );
3478                 $options = [];
3479                 if ( $limit > -1 ) {
3480                         $options['LIMIT'] = $limit;
3481                 }
3482                 return TitleArray::newFromResult(
3483                         $dbr->select( 'page',
3484                                 [ 'page_id', 'page_namespace', 'page_title', 'page_is_redirect' ],
3485                                 $conds,
3486                                 __METHOD__,
3487                                 $options
3488                         )
3489                 );
3490         }
3491
3492         /**
3493          * Is there a version of this page in the deletion archive?
3494          *
3495          * @return int The number of archived revisions
3496          */
3497         public function isDeleted() {
3498                 if ( $this->mNamespace < 0 ) {
3499                         $n = 0;
3500                 } else {
3501                         $dbr = wfGetDB( DB_REPLICA );
3502
3503                         $n = $dbr->selectField( 'archive', 'COUNT(*)',
3504                                 [ 'ar_namespace' => $this->mNamespace, 'ar_title' => $this->mDbkeyform ],
3505                                 __METHOD__
3506                         );
3507                         if ( $this->mNamespace == NS_FILE ) {
3508                                 $n += $dbr->selectField( 'filearchive', 'COUNT(*)',
3509                                         [ 'fa_name' => $this->mDbkeyform ],
3510                                         __METHOD__
3511                                 );
3512                         }
3513                 }
3514                 return (int)$n;
3515         }
3516
3517         /**
3518          * Is there a version of this page in the deletion archive?
3519          *
3520          * @return bool
3521          */
3522         public function isDeletedQuick() {
3523                 if ( $this->mNamespace < 0 ) {
3524                         return false;
3525                 }
3526                 $dbr = wfGetDB( DB_REPLICA );
3527                 $deleted = (bool)$dbr->selectField( 'archive', '1',
3528                         [ 'ar_namespace' => $this->mNamespace, 'ar_title' => $this->mDbkeyform ],
3529                         __METHOD__
3530                 );
3531                 if ( !$deleted && $this->mNamespace == NS_FILE ) {
3532                         $deleted = (bool)$dbr->selectField( 'filearchive', '1',
3533                                 [ 'fa_name' => $this->mDbkeyform ],
3534                                 __METHOD__
3535                         );
3536                 }
3537                 return $deleted;
3538         }
3539
3540         /**
3541          * Get the article ID for this Title from the link cache,
3542          * adding it if necessary
3543          *
3544          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select
3545          *  for update
3546          * @return int The ID
3547          */
3548         public function getArticleID( $flags = 0 ) {
3549                 if ( $this->mNamespace < 0 ) {
3550                         $this->mArticleID = 0;
3551                         return $this->mArticleID;
3552                 }
3553                 $linkCache = MediaWikiServices::getInstance()->getLinkCache();
3554                 if ( $flags & self::GAID_FOR_UPDATE ) {
3555                         $oldUpdate = $linkCache->forUpdate( true );
3556                         $linkCache->clearLink( $this );
3557                         $this->mArticleID = $linkCache->addLinkObj( $this );
3558                         $linkCache->forUpdate( $oldUpdate );
3559                 } else {
3560                         if ( $this->mArticleID == -1 ) {
3561                                 $this->mArticleID = $linkCache->addLinkObj( $this );
3562                         }
3563                 }
3564                 return $this->mArticleID;
3565         }
3566
3567         /**
3568          * Is this an article that is a redirect page?
3569          * Uses link cache, adding it if necessary
3570          *
3571          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3572          * @return bool
3573          */
3574         public function isRedirect( $flags = 0 ) {
3575                 if ( !is_null( $this->mRedirect ) ) {
3576                         return $this->mRedirect;
3577                 }
3578                 if ( !$this->getArticleID( $flags ) ) {
3579                         $this->mRedirect = false;
3580                         return $this->mRedirect;
3581                 }
3582
3583                 $linkCache = MediaWikiServices::getInstance()->getLinkCache();
3584                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3585                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'redirect' );
3586                 if ( $cached === null ) {
3587                         # Trust LinkCache's state over our own
3588                         # LinkCache is telling us that the page doesn't exist, despite there being cached
3589                         # data relating to an existing page in $this->mArticleID. Updaters should clear
3590                         # LinkCache as appropriate, or use $flags = Title::GAID_FOR_UPDATE. If that flag is
3591                         # set, then LinkCache will definitely be up to date here, since getArticleID() forces
3592                         # LinkCache to refresh its data from the master.
3593                         $this->mRedirect = false;
3594                         return $this->mRedirect;
3595                 }
3596
3597                 $this->mRedirect = (bool)$cached;
3598
3599                 return $this->mRedirect;
3600         }
3601
3602         /**
3603          * What is the length of this page?
3604          * Uses link cache, adding it if necessary
3605          *
3606          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3607          * @return int
3608          */
3609         public function getLength( $flags = 0 ) {
3610                 if ( $this->mLength != -1 ) {
3611                         return $this->mLength;
3612                 }
3613                 if ( !$this->getArticleID( $flags ) ) {
3614                         $this->mLength = 0;
3615                         return $this->mLength;
3616                 }
3617                 $linkCache = MediaWikiServices::getInstance()->getLinkCache();
3618                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3619                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'length' );
3620                 if ( $cached === null ) {
3621                         # Trust LinkCache's state over our own, as for isRedirect()
3622                         $this->mLength = 0;
3623                         return $this->mLength;
3624                 }
3625
3626                 $this->mLength = intval( $cached );
3627
3628                 return $this->mLength;
3629         }
3630
3631         /**
3632          * What is the page_latest field for this page?
3633          *
3634          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3635          * @return int Int or 0 if the page doesn't exist
3636          */
3637         public function getLatestRevID( $flags = 0 ) {
3638                 if ( !( $flags & self::GAID_FOR_UPDATE ) && $this->mLatestID !== false ) {
3639                         return intval( $this->mLatestID );
3640                 }
3641                 if ( !$this->getArticleID( $flags ) ) {
3642                         $this->mLatestID = 0;
3643                         return $this->mLatestID;
3644                 }
3645                 $linkCache = MediaWikiServices::getInstance()->getLinkCache();
3646                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3647                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'revision' );
3648                 if ( $cached === null ) {
3649                         # Trust LinkCache's state over our own, as for isRedirect()
3650                         $this->mLatestID = 0;
3651                         return $this->mLatestID;
3652                 }
3653
3654                 $this->mLatestID = intval( $cached );
3655
3656                 return $this->mLatestID;
3657         }
3658
3659         /**
3660          * This clears some fields in this object, and clears any associated
3661          * keys in the "bad links" section of the link cache.
3662          *
3663          * - This is called from WikiPage::doEditContent() and WikiPage::insertOn() to allow
3664          * loading of the new page_id. It's also called from
3665          * WikiPage::doDeleteArticleReal()
3666          *
3667          * @param int $newid The new Article ID
3668          */
3669         public function resetArticleID( $newid ) {
3670                 $linkCache = MediaWikiServices::getInstance()->getLinkCache();
3671                 $linkCache->clearLink( $this );
3672
3673                 if ( $newid === false ) {
3674                         $this->mArticleID = -1;
3675                 } else {
3676                         $this->mArticleID = intval( $newid );
3677                 }
3678                 $this->mRestrictionsLoaded = false;
3679                 $this->mRestrictions = [];
3680                 $this->mOldRestrictions = false;
3681                 $this->mRedirect = null;
3682                 $this->mLength = -1;
3683                 $this->mLatestID = false;
3684                 $this->mContentModel = false;
3685                 $this->mEstimateRevisions = null;
3686                 $this->mPageLanguage = false;
3687                 $this->mDbPageLanguage = false;
3688                 $this->mIsBigDeletion = null;
3689         }
3690
3691         public static function clearCaches() {
3692                 $linkCache = MediaWikiServices::getInstance()->getLinkCache();
3693                 $linkCache->clear();
3694
3695                 $titleCache = self::getTitleCache();
3696                 $titleCache->clear();
3697         }
3698
3699         /**
3700          * Capitalize a text string for a title if it belongs to a namespace that capitalizes
3701          *
3702          * @param string $text Containing title to capitalize
3703          * @param int $ns Namespace index, defaults to NS_MAIN
3704          * @return string Containing capitalized title
3705          */
3706         public static function capitalize( $text, $ns = NS_MAIN ) {
3707                 if ( MWNamespace::isCapitalized( $ns ) ) {
3708                         return MediaWikiServices::getInstance()->getContentLanguage()->ucfirst( $text );
3709                 } else {
3710                         return $text;
3711                 }
3712         }
3713
3714         /**
3715          * Secure and split - main initialisation function for this object
3716          *
3717          * Assumes that mDbkeyform has been set, and is urldecoded
3718          * and uses underscores, but not otherwise munged.  This function
3719          * removes illegal characters, splits off the interwiki and
3720          * namespace prefixes, sets the other forms, and canonicalizes
3721          * everything.
3722          *
3723          * @throws MalformedTitleException On invalid titles
3724          * @return bool True on success
3725          */
3726         private function secureAndSplit() {
3727                 // @note: splitTitleString() is a temporary hack to allow MediaWikiTitleCodec to share
3728                 //        the parsing code with Title, while avoiding massive refactoring.
3729                 // @todo: get rid of secureAndSplit, refactor parsing code.
3730                 // @note: getTitleParser() returns a TitleParser implementation which does not have a
3731                 //        splitTitleString method, but the only implementation (MediaWikiTitleCodec) does
3732                 /** @var MediaWikiTitleCodec $titleCodec */
3733                 $titleCodec = MediaWikiServices::getInstance()->getTitleParser();
3734                 // MalformedTitleException can be thrown here
3735                 $parts = $titleCodec->splitTitleString( $this->mDbkeyform, $this->mDefaultNamespace );
3736
3737                 # Fill fields
3738                 $this->setFragment( '#' . $parts['fragment'] );
3739                 $this->mInterwiki = $parts['interwiki'];
3740                 $this->mLocalInterwiki = $parts['local_interwiki'];
3741                 $this->mNamespace = $parts['namespace'];
3742                 $this->mUserCaseDBKey = $parts['user_case_dbkey'];
3743
3744                 $this->mDbkeyform = $parts['dbkey'];
3745                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
3746                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
3747
3748                 # We already know that some pages won't be in the database!
3749                 if ( $this->isExternal() || $this->isSpecialPage() ) {
3750                         $this->mArticleID = 0;
3751                 }
3752
3753                 return true;
3754         }
3755
3756         /**
3757          * Get an array of Title objects linking to this Title
3758          * Also stores the IDs in the link cache.
3759          *
3760          * WARNING: do not use this function on arbitrary user-supplied titles!
3761          * On heavily-used templates it will max out the memory.
3762          *
3763          * @param array $options May be FOR UPDATE
3764          * @param string $table Table name
3765          * @param string $prefix Fields prefix
3766          * @return Title[] Array of Title objects linking here
3767          */
3768         public function getLinksTo( $options = [], $table = 'pagelinks', $prefix = 'pl' ) {
3769                 if ( count( $options ) > 0 ) {
3770                         $db = wfGetDB( DB_MASTER );
3771                 } else {
3772                         $db = wfGetDB( DB_REPLICA );
3773                 }
3774
3775                 $res = $db->select(
3776                         [ 'page', $table ],
3777                         self::getSelectFields(),
3778                         [
3779                                 "{$prefix}_from=page_id",
3780                                 "{$prefix}_namespace" => $this->mNamespace,
3781                                 "{$prefix}_title" => $this->mDbkeyform ],
3782                         __METHOD__,
3783                         $options
3784                 );
3785
3786                 $retVal = [];
3787                 if ( $res->numRows() ) {
3788                         $linkCache = MediaWikiServices::getInstance()->getLinkCache();
3789                         foreach ( $res as $row ) {
3790                                 $titleObj = self::makeTitle( $row->page_namespace, $row->page_title );
3791                                 if ( $titleObj ) {
3792                                         $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3793                                         $retVal[] = $titleObj;
3794                                 }
3795                         }
3796                 }
3797                 return $retVal;
3798         }
3799
3800         /**
3801          * Get an array of Title objects using this Title as a template
3802          * Also stores the IDs in the link cache.
3803          *
3804          * WARNING: do not use this function on arbitrary user-supplied titles!
3805          * On heavily-used templates it will max out the memory.
3806          *
3807          * @param array $options Query option to Database::select()
3808          * @return Title[] Array of Title the Title objects linking here
3809          */
3810         public function getTemplateLinksTo( $options = [] ) {
3811                 return $this->getLinksTo( $options, 'templatelinks', 'tl' );
3812         }
3813
3814         /**
3815          * Get an array of Title objects linked from this Title
3816          * Also stores the IDs in the link cache.
3817          *
3818          * WARNING: do not use this function on arbitrary user-supplied titles!
3819          * On heavily-used templates it will max out the memory.
3820          *
3821          * @param array $options Query option to Database::select()
3822          * @param string $table Table name
3823          * @param string $prefix Fields prefix
3824          * @return array Array of Title objects linking here
3825          */
3826         public function getLinksFrom( $options = [], $table = 'pagelinks', $prefix = 'pl' ) {
3827                 $id = $this->getArticleID();
3828
3829                 # If the page doesn't exist; there can't be any link from this page
3830                 if ( !$id ) {
3831                         return [];
3832                 }
3833
3834                 $db = wfGetDB( DB_REPLICA );
3835
3836                 $blNamespace = "{$prefix}_namespace";
3837                 $blTitle = "{$prefix}_title";
3838
3839                 $pageQuery = WikiPage::getQueryInfo();
3840                 $res = $db->select(
3841                         [ $table, 'nestpage' => $pageQuery['tables'] ],
3842                         array_merge(
3843                                 [ $blNamespace, $blTitle ],
3844                                 $pageQuery['fields']
3845                         ),
3846                         [ "{$prefix}_from" => $id ],
3847                         __METHOD__,
3848                         $options,
3849                         [ 'nestpage' => [
3850                                 'LEFT JOIN',
3851                                 [ "page_namespace=$blNamespace", "page_title=$blTitle" ]
3852                         ] ] + $pageQuery['joins']
3853                 );
3854
3855                 $retVal = [];
3856                 $linkCache = MediaWikiServices::getInstance()->getLinkCache();
3857                 foreach ( $res as $row ) {
3858                         if ( $row->page_id ) {
3859                                 $titleObj = self::newFromRow( $row );
3860                         } else {
3861                                 $titleObj = self::makeTitle( $row->$blNamespace, $row->$blTitle );
3862                                 $linkCache->addBadLinkObj( $titleObj );
3863                         }
3864                         $retVal[] = $titleObj;
3865                 }
3866
3867                 return $retVal;
3868         }
3869
3870         /**
3871          * Get an array of Title objects used on this Title as a template
3872          * Also stores the IDs in the link cache.
3873          *
3874          * WARNING: do not use this function on arbitrary user-supplied titles!
3875          * On heavily-used templates it will max out the memory.
3876          *
3877          * @param array $options May be FOR UPDATE
3878          * @return Title[] Array of Title the Title objects used here
3879          */
3880         public function getTemplateLinksFrom( $options = [] ) {
3881                 return $this->getLinksFrom( $options, 'templatelinks', 'tl' );
3882         }
3883
3884         /**
3885          * Get an array of Title objects referring to non-existent articles linked
3886          * from this page.
3887          *
3888          * @todo check if needed (used only in SpecialBrokenRedirects.php, and
3889          *   should use redirect table in this case).
3890          * @return Title[] Array of Title the Title objects
3891          */
3892         public function getBrokenLinksFrom() {
3893                 if ( $this->getArticleID() == 0 ) {
3894                         # All links from article ID 0 are false positives
3895                         return [];
3896                 }
3897
3898                 $dbr = wfGetDB( DB_REPLICA );
3899                 $res = $dbr->select(
3900                         [ 'page', 'pagelinks' ],
3901                         [ 'pl_namespace', 'pl_title' ],
3902                         [
3903                                 'pl_from' => $this->getArticleID(),
3904                                 'page_namespace IS NULL'
3905                         ],
3906                         __METHOD__, [],
3907                         [
3908                                 'page' => [
3909                                         'LEFT JOIN',
3910                                         [ 'pl_namespace=page_namespace', 'pl_title=page_title' ]
3911                                 ]
3912                         ]
3913                 );
3914
3915                 $retVal = [];
3916                 foreach ( $res as $row ) {
3917                         $retVal[] = self::makeTitle( $row->pl_namespace, $row->pl_title );
3918                 }
3919                 return $retVal;
3920         }
3921
3922         /**
3923          * Get a list of URLs to purge from the CDN cache when this
3924          * page changes
3925          *
3926          * @return string[] Array of String the URLs
3927          */
3928         public function getCdnUrls() {
3929                 $urls = [
3930                         $this->getInternalURL(),
3931                         $this->getInternalURL( 'action=history' )
3932                 ];
3933
3934                 $pageLang = $this->getPageLanguage();
3935                 if ( $pageLang->hasVariants() ) {
3936                         $variants = $pageLang->getVariants();
3937                         foreach ( $variants as $vCode ) {
3938                                 $urls[] = $this->getInternalURL( $vCode );
3939                         }
3940                 }
3941
3942                 // If we are looking at a css/js user subpage, purge the action=raw.
3943                 if ( $this->isUserJsConfigPage() ) {
3944                         $urls[] = $this->getInternalURL( 'action=raw&ctype=text/javascript' );
3945                 } elseif ( $this->isUserJsonConfigPage() ) {
3946                         $urls[] = $this->getInternalURL( 'action=raw&ctype=application/json' );
3947                 } elseif ( $this->isUserCssConfigPage() ) {
3948                         $urls[] = $this->getInternalURL( 'action=raw&ctype=text/css' );
3949                 }
3950
3951                 Hooks::run( 'TitleSquidURLs', [ $this, &$urls ] );
3952                 return $urls;
3953         }
3954
3955         /**
3956          * Purge all applicable CDN URLs
3957          */
3958         public function purgeSquid() {
3959                 DeferredUpdates::addUpdate(
3960                         new CdnCacheUpdate( $this->getCdnUrls() ),
3961                         DeferredUpdates::PRESEND
3962                 );
3963         }
3964
3965         /**
3966          * Check whether a given move operation would be valid.
3967          * Returns true if ok, or a getUserPermissionsErrors()-like array otherwise
3968          *
3969          * @deprecated since 1.25, use MovePage's methods instead
3970          * @param Title &$nt The new title
3971          * @param bool $auth Whether to check user permissions (uses $wgUser)
3972          * @param string $reason Is the log summary of the move, used for spam checking
3973          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3974          */
3975         public function isValidMoveOperation( &$nt, $auth = true, $reason = '' ) {
3976                 global $wgUser;
3977
3978                 if ( !( $nt instanceof Title ) ) {
3979                         // Normally we'd add this to $errors, but we'll get
3980                         // lots of syntax errors if $nt is not an object
3981                         return [ [ 'badtitletext' ] ];
3982                 }
3983
3984                 $mp = new MovePage( $this, $nt );
3985                 $errors = $mp->isValidMove()->getErrorsArray();
3986                 if ( $auth ) {
3987                         $errors = wfMergeErrorArrays(
3988                                 $errors,
3989                                 $mp->checkPermissions( $wgUser, $reason )->getErrorsArray()
3990                         );
3991                 }
3992
3993                 return $errors ?: true;
3994         }
3995
3996         /**
3997          * Move a title to a new location
3998          *
3999          * @deprecated since 1.25, use the MovePage class instead
4000          * @param Title &$nt The new title
4001          * @param bool $auth Indicates whether $wgUser's permissions
4002          *  should be checked
4003          * @param string $reason The reason for the move
4004          * @param bool $createRedirect Whether to create a redirect from the old title to the new title.
4005          *  Ignored if the user doesn't have the suppressredirect right.
4006          * @param array $changeTags Applied to the entry in the move log and redirect page revision
4007          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
4008          */
4009         public function moveTo( &$nt, $auth = true, $reason = '', $createRedirect = true,
4010                 array $changeTags = []
4011         ) {
4012                 global $wgUser;
4013                 $err = $this->isValidMoveOperation( $nt, $auth, $reason );
4014                 if ( is_array( $err ) ) {
4015                         // Auto-block user's IP if the account was "hard" blocked
4016                         $wgUser->spreadAnyEditBlock();
4017                         return $err;
4018                 }
4019                 // Check suppressredirect permission
4020                 if ( $auth && !$wgUser->isAllowed( 'suppressredirect' ) ) {
4021                         $createRedirect = true;
4022                 }
4023
4024                 $mp = new MovePage( $this, $nt );
4025                 $status = $mp->move( $wgUser, $reason, $createRedirect, $changeTags );
4026                 if ( $status->isOK() ) {
4027                         return true;
4028                 } else {
4029                         return $status->getErrorsArray();
4030                 }
4031         }
4032
4033         /**
4034          * Move this page's subpages to be subpages of $nt
4035          *
4036          * @param Title $nt Move target
4037          * @param bool $auth Whether $wgUser's permissions should be checked
4038          * @param string $reason The reason for the move
4039          * @param bool $createRedirect Whether to create redirects from the old subpages to
4040          *     the new ones Ignored if the user doesn't have the 'suppressredirect' right
4041          * @param array $changeTags Applied to the entry in the move log and redirect page revision
4042          * @return array Array with old page titles as keys, and strings (new page titles) or
4043          *     getUserPermissionsErrors()-like arrays (errors) as values, or a
4044          *     getUserPermissionsErrors()-like error array with numeric indices if
4045          *     no pages were moved
4046          */
4047         public function moveSubpages( $nt, $auth = true, $reason = '', $createRedirect = true,
4048                 array $changeTags = []
4049         ) {
4050                 global $wgMaximumMovedPages;
4051                 // Check permissions
4052                 if ( !$this->userCan( 'move-subpages' ) ) {
4053                         return [
4054                                 [ 'cant-move-subpages' ],
4055                         ];
4056                 }
4057                 // Do the source and target namespaces support subpages?
4058                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
4059                         return [
4060                                 [ 'namespace-nosubpages', MWNamespace::getCanonicalName( $this->mNamespace ) ],
4061                         ];
4062                 }
4063                 if ( !MWNamespace::hasSubpages( $nt->getNamespace() ) ) {
4064                         return [
4065                                 [ 'namespace-nosubpages', MWNamespace::getCanonicalName( $nt->getNamespace() ) ],
4066                         ];
4067                 }
4068
4069                 $subpages = $this->getSubpages( $wgMaximumMovedPages + 1 );
4070                 $retval = [];
4071                 $count = 0;
4072                 foreach ( $subpages as $oldSubpage ) {
4073                         $count++;
4074                         if ( $count > $wgMaximumMovedPages ) {
4075                                 $retval[$oldSubpage->getPrefixedText()] = [
4076                                         [ 'movepage-max-pages', $wgMaximumMovedPages ],
4077                                 ];
4078                                 break;
4079                         }
4080
4081                         // We don't know whether this function was called before
4082                         // or after moving the root page, so check both
4083                         // $this and $nt
4084                         if ( $oldSubpage->getArticleID() == $this->getArticleID()
4085                                 || $oldSubpage->getArticleID() == $nt->getArticleID()
4086                         ) {
4087                                 // When moving a page to a subpage of itself,
4088                                 // don't move it twice
4089                                 continue;
4090                         }
4091                         $newPageName = preg_replace(
4092                                         '#^' . preg_quote( $this->mDbkeyform, '#' ) . '#',
4093                                         StringUtils::escapeRegexReplacement( $nt->getDBkey() ), # T23234
4094                                         $oldSubpage->getDBkey() );
4095                         if ( $oldSubpage->isTalkPage() ) {
4096                                 $newNs = $nt->getTalkPage()->getNamespace();
4097                         } else {
4098                                 $newNs = $nt->getSubjectPage()->getNamespace();
4099                         }
4100                         # T16385: we need makeTitleSafe because the new page names may
4101                         # be longer than 255 characters.
4102                         $newSubpage = self::makeTitleSafe( $newNs, $newPageName );
4103
4104                         $success = $oldSubpage->moveTo( $newSubpage, $auth, $reason, $createRedirect, $changeTags );
4105                         if ( $success === true ) {
4106                                 $retval[$oldSubpage->getPrefixedText()] = $newSubpage->getPrefixedText();
4107                         } else {
4108                                 $retval[$oldSubpage->getPrefixedText()] = $success;
4109                         }
4110                 }
4111                 return $retval;
4112         }
4113
4114         /**
4115          * Checks if this page is just a one-rev redirect.
4116          * Adds lock, so don't use just for light purposes.
4117          *
4118          * @return bool
4119          */
4120         public function isSingleRevRedirect() {
4121                 global $wgContentHandlerUseDB;
4122
4123                 $dbw = wfGetDB( DB_MASTER );
4124
4125                 # Is it a redirect?
4126                 $fields = [ 'page_is_redirect', 'page_latest', 'page_id' ];
4127                 if ( $wgContentHandlerUseDB ) {
4128                         $fields[] = 'page_content_model';
4129                 }
4130
4131                 $row = $dbw->selectRow( 'page',
4132                         $fields,
4133                         $this->pageCond(),
4134                         __METHOD__,
4135                         [ 'FOR UPDATE' ]
4136                 );
4137                 # Cache some fields we may want
4138                 $this->mArticleID = $row ? intval( $row->page_id ) : 0;
4139                 $this->mRedirect = $row ? (bool)$row->page_is_redirect : false;
4140                 $this->mLatestID = $row ? intval( $row->page_latest ) : false;
4141                 $this->mContentModel = $row && isset( $row->page_content_model )
4142                         ? strval( $row->page_content_model )
4143                         : false;
4144
4145                 if ( !$this->mRedirect ) {
4146                         return false;
4147                 }
4148                 # Does the article have a history?
4149                 $row = $dbw->selectField( [ 'page', 'revision' ],
4150                         'rev_id',
4151                         [ 'page_namespace' => $this->mNamespace,
4152                                 'page_title' => $this->mDbkeyform,
4153                                 'page_id=rev_page',
4154                                 'page_latest != rev_id'
4155                         ],
4156                         __METHOD__,
4157                         [ 'FOR UPDATE' ]
4158                 );
4159                 # Return true if there was no history
4160                 return ( $row === false );
4161         }
4162
4163         /**
4164          * Checks if $this can be moved to a given Title
4165          * - Selects for update, so don't call it unless you mean business
4166          *
4167          * @deprecated since 1.25, use MovePage's methods instead
4168          * @param Title $nt The new title to check
4169          * @return bool
4170          */
4171         public function isValidMoveTarget( $nt ) {
4172                 # Is it an existing file?
4173                 if ( $nt->getNamespace() == NS_FILE ) {
4174                         $file = wfLocalFile( $nt );
4175                         $file->load( File::READ_LATEST );
4176                         if ( $file->exists() ) {
4177                                 wfDebug( __METHOD__ . ": file exists\n" );
4178                                 return false;
4179                         }
4180                 }
4181                 # Is it a redirect with no history?
4182                 if ( !$nt->isSingleRevRedirect() ) {
4183                         wfDebug( __METHOD__ . ": not a one-rev redirect\n" );
4184                         return false;
4185                 }
4186                 # Get the article text
4187                 $rev = Revision::newFromTitle( $nt, false, Revision::READ_LATEST );
4188                 if ( !is_object( $rev ) ) {
4189                         return false;
4190                 }
4191                 $content = $rev->getContent();
4192                 # Does the redirect point to the source?
4193                 # Or is it a broken self-redirect, usually caused by namespace collisions?
4194                 $redirTitle = $content ? $content->getRedirectTarget() : null;
4195
4196                 if ( $redirTitle ) {
4197                         if ( $redirTitle->getPrefixedDBkey() != $this->getPrefixedDBkey() &&
4198                                 $redirTitle->getPrefixedDBkey() != $nt->getPrefixedDBkey() ) {
4199                                 wfDebug( __METHOD__ . ": redirect points to other page\n" );
4200                                 return false;
4201                         } else {
4202                                 return true;
4203                         }
4204                 } else {
4205                         # Fail safe (not a redirect after all. strange.)
4206                         wfDebug( __METHOD__ . ": failsafe: database sais " . $nt->getPrefixedDBkey() .
4207                                                 " is a redirect, but it doesn't contain a valid redirect.\n" );
4208                         return false;
4209                 }
4210         }
4211
4212         /**
4213          * Get categories to which this Title belongs and return an array of
4214          * categories' names.
4215          *
4216          * @return array Array of parents in the form:
4217          *     $parent => $currentarticle
4218          */
4219         public function getParentCategories() {
4220                 $data = [];
4221
4222                 $titleKey = $this->getArticleID();
4223
4224                 if ( $titleKey === 0 ) {
4225                         return $data;
4226                 }
4227
4228                 $dbr = wfGetDB( DB_REPLICA );
4229
4230                 $res = $dbr->select(
4231                         'categorylinks',
4232                         'cl_to',
4233                         [ 'cl_from' => $titleKey ],
4234                         __METHOD__
4235                 );
4236
4237                 if ( $res->numRows() > 0 ) {
4238                         $contLang = MediaWikiServices::getInstance()->getContentLanguage();
4239                         foreach ( $res as $row ) {
4240                                 // $data[] = Title::newFromText( $contLang->getNsText ( NS_CATEGORY ).':'.$row->cl_to);
4241                                 $data[$contLang->getNsText( NS_CATEGORY ) . ':' . $row->cl_to] =
4242                                         $this->getFullText();
4243                         }
4244                 }
4245                 return $data;
4246         }
4247
4248         /**
4249          * Get a tree of parent categories
4250          *
4251          * @param array $children Array with the children in the keys, to check for circular refs
4252          * @return array Tree of parent categories
4253          */
4254         public function getParentCategoryTree( $children = [] ) {
4255                 $stack = [];
4256                 $parents = $this->getParentCategories();
4257
4258                 if ( $parents ) {
4259                         foreach ( $parents as $parent => $current ) {
4260                                 if ( array_key_exists( $parent, $children ) ) {
4261                                         # Circular reference
4262                                         $stack[$parent] = [];
4263                                 } else {
4264                                         $nt = self::newFromText( $parent );
4265                                         if ( $nt ) {
4266                                                 $stack[$parent] = $nt->getParentCategoryTree( $children + [ $parent => 1 ] );
4267                                         }
4268                                 }
4269                         }
4270                 }
4271
4272                 return $stack;
4273         }
4274
4275         /**
4276          * Get an associative array for selecting this title from
4277          * the "page" table
4278          *
4279          * @return array Array suitable for the $where parameter of DB::select()
4280          */
4281         public function pageCond() {
4282                 if ( $this->mArticleID > 0 ) {
4283                         // PK avoids secondary lookups in InnoDB, shouldn't hurt other DBs
4284                         return [ 'page_id' => $this->mArticleID ];
4285                 } else {
4286                         return [ 'page_namespace' => $this->mNamespace, 'page_title' => $this->mDbkeyform ];
4287                 }
4288         }
4289
4290         /**
4291          * Get next/previous revision ID relative to another revision ID
4292          * @param int $revId Revision ID. Get the revision that was before this one.
4293          * @param int $flags Title::GAID_FOR_UPDATE
4294          * @param string $dir 'next' or 'prev'
4295          * @return int|bool New revision ID, or false if none exists
4296          */
4297         private function getRelativeRevisionID( $revId, $flags, $dir ) {
4298                 $revId = (int)$revId;
4299                 if ( $dir === 'next' ) {
4300                         $op = '>';
4301                         $sort = 'ASC';
4302                 } elseif ( $dir === 'prev' ) {
4303                         $op = '<';
4304                         $sort = 'DESC';
4305                 } else {
4306                         throw new InvalidArgumentException( '$dir must be "next" or "prev"' );
4307                 }
4308
4309                 if ( $flags & self::GAID_FOR_UPDATE ) {
4310                         $db = wfGetDB( DB_MASTER );
4311                 } else {
4312                         $db = wfGetDB( DB_REPLICA, 'contributions' );
4313                 }
4314
4315                 // Intentionally not caring if the specified revision belongs to this
4316                 // page. We only care about the timestamp.
4317                 $ts = $db->selectField( 'revision', 'rev_timestamp', [ 'rev_id' => $revId ], __METHOD__ );
4318                 if ( $ts === false ) {
4319                         $ts = $db->selectField( 'archive', 'ar_timestamp', [ 'ar_rev_id' => $revId ], __METHOD__ );
4320                         if ( $ts === false ) {
4321                                 // Or should this throw an InvalidArgumentException or something?
4322                                 return false;
4323                         }
4324                 }
4325                 $ts = $db->addQuotes( $ts );
4326
4327                 $revId = $db->selectField( 'revision', 'rev_id',
4328                         [
4329                                 'rev_page' => $this->getArticleID( $flags ),
4330                                 "rev_timestamp $op $ts OR (rev_timestamp = $ts AND rev_id $op $revId)"
4331                         ],
4332                         __METHOD__,
4333                         [
4334                                 'ORDER BY' => "rev_timestamp $sort, rev_id $sort",
4335                                 'IGNORE INDEX' => 'rev_timestamp', // Probably needed for T159319
4336                         ]
4337                 );
4338
4339                 if ( $revId === false ) {
4340                         return false;
4341                 } else {
4342                         return intval( $revId );
4343                 }
4344         }
4345
4346         /**
4347          * Get the revision ID of the previous revision
4348          *
4349          * @param int $revId Revision ID. Get the revision that was before this one.
4350          * @param int $flags Title::GAID_FOR_UPDATE
4351          * @return int|bool Old revision ID, or false if none exists
4352          */
4353         public function getPreviousRevisionID( $revId, $flags = 0 ) {
4354                 return $this->getRelativeRevisionID( $revId, $flags, 'prev' );
4355         }
4356
4357         /**
4358          * Get the revision ID of the next revision
4359          *
4360          * @param int $revId Revision ID. Get the revision that was after this one.
4361          * @param int $flags Title::GAID_FOR_UPDATE
4362          * @return int|bool Next revision ID, or false if none exists
4363          */
4364         public function getNextRevisionID( $revId, $flags = 0 ) {
4365                 return $this->getRelativeRevisionID( $revId, $flags, 'next' );
4366         }
4367
4368         /**
4369          * Get the first revision of the page
4370          *
4371          * @param int $flags Title::GAID_FOR_UPDATE
4372          * @return Revision|null If page doesn't exist
4373          */
4374         public function getFirstRevision( $flags = 0 ) {
4375                 $pageId = $this->getArticleID( $flags );
4376                 if ( $pageId ) {
4377                         $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_REPLICA );
4378                         $revQuery = Revision::getQueryInfo();
4379                         $row = $db->selectRow( $revQuery['tables'], $revQuery['fields'],
4380                                 [ 'rev_page' => $pageId ],
4381                                 __METHOD__,
4382                                 [
4383                                         'ORDER BY' => 'rev_timestamp ASC, rev_id ASC',
4384                                         'IGNORE INDEX' => [ 'revision' => 'rev_timestamp' ], // See T159319
4385                                 ],
4386                                 $revQuery['joins']
4387                         );
4388                         if ( $row ) {
4389                                 return new Revision( $row, 0, $this );
4390                         }
4391                 }
4392                 return null;
4393         }
4394
4395         /**
4396          * Get the oldest revision timestamp of this page
4397          *
4398          * @param int $flags Title::GAID_FOR_UPDATE
4399          * @return string|null MW timestamp
4400          */
4401         public function getEarliestRevTime( $flags = 0 ) {
4402                 $rev = $this->getFirstRevision( $flags );
4403                 return $rev ? $rev->getTimestamp() : null;
4404         }
4405
4406         /**
4407          * Check if this is a new page
4408          *
4409          * @return bool
4410          */
4411         public function isNewPage() {
4412                 $dbr = wfGetDB( DB_REPLICA );
4413                 return (bool)$dbr->selectField( 'page', 'page_is_new', $this->pageCond(), __METHOD__ );
4414         }
4415
4416         /**
4417          * Check whether the number of revisions of this page surpasses $wgDeleteRevisionsLimit
4418          *
4419          * @return bool
4420          */
4421         public function isBigDeletion() {
4422                 global $wgDeleteRevisionsLimit;
4423
4424                 if ( !$wgDeleteRevisionsLimit ) {
4425                         return false;
4426                 }
4427
4428                 if ( $this->mIsBigDeletion === null ) {
4429                         $dbr = wfGetDB( DB_REPLICA );
4430
4431                         $revCount = $dbr->selectRowCount(
4432                                 'revision',
4433                                 '1',
4434                                 [ 'rev_page' => $this->getArticleID() ],
4435                                 __METHOD__,
4436                                 [ 'LIMIT' => $wgDeleteRevisionsLimit + 1 ]
4437                         );
4438
4439                         $this->mIsBigDeletion = $revCount > $wgDeleteRevisionsLimit;
4440                 }
4441
4442                 return $this->mIsBigDeletion;
4443         }
4444
4445         /**
4446          * Get the approximate revision count of this page.
4447          *
4448          * @return int
4449          */
4450         public function estimateRevisionCount() {
4451                 if ( !$this->exists() ) {
4452                         return 0;
4453                 }
4454
4455                 if ( $this->mEstimateRevisions === null ) {
4456                         $dbr = wfGetDB( DB_REPLICA );
4457                         $this->mEstimateRevisions = $dbr->estimateRowCount( 'revision', '*',
4458                                 [ 'rev_page' => $this->getArticleID() ], __METHOD__ );
4459                 }
4460
4461                 return $this->mEstimateRevisions;
4462         }
4463
4464         /**
4465          * Get the number of revisions between the given revision.
4466          * Used for diffs and other things that really need it.
4467          *
4468          * @param int|Revision $old Old revision or rev ID (first before range)
4469          * @param int|Revision $new New revision or rev ID (first after range)
4470          * @param int|null $max Limit of Revisions to count, will be incremented to detect truncations
4471          * @return int Number of revisions between these revisions.
4472          */
4473         public function countRevisionsBetween( $old, $new, $max = null ) {
4474                 if ( !( $old instanceof Revision ) ) {
4475                         $old = Revision::newFromTitle( $this, (int)$old );
4476                 }
4477                 if ( !( $new instanceof Revision ) ) {
4478                         $new = Revision::newFromTitle( $this, (int)$new );
4479                 }
4480                 if ( !$old || !$new ) {
4481                         return 0; // nothing to compare
4482                 }
4483                 $dbr = wfGetDB( DB_REPLICA );
4484                 $conds = [
4485                         'rev_page' => $this->getArticleID(),
4486                         'rev_timestamp > ' . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4487                         'rev_timestamp < ' . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4488                 ];
4489                 if ( $max !== null ) {
4490                         return $dbr->selectRowCount( 'revision', '1',
4491                                 $conds,
4492                                 __METHOD__,
4493                                 [ 'LIMIT' => $max + 1 ] // extra to detect truncation
4494                         );
4495                 } else {
4496                         return (int)$dbr->selectField( 'revision', 'count(*)', $conds, __METHOD__ );
4497                 }
4498         }
4499
4500         /**
4501          * Get the authors between the given revisions or revision IDs.
4502          * Used for diffs and other things that really need it.
4503          *
4504          * @since 1.23
4505          *
4506          * @param int|Revision $old Old revision or rev ID (first before range by default)
4507          * @param int|Revision $new New revision or rev ID (first after range by default)
4508          * @param int $limit Maximum number of authors
4509          * @param string|array $options (Optional): Single option, or an array of options:
4510          *     'include_old' Include $old in the range; $new is excluded.
4511          *     'include_new' Include $new in the range; $old is excluded.
4512          *     'include_both' Include both $old and $new in the range.
4513          *     Unknown option values are ignored.
4514          * @return array|null Names of revision authors in the range; null if not both revisions exist
4515          */
4516         public function getAuthorsBetween( $old, $new, $limit, $options = [] ) {
4517                 if ( !( $old instanceof Revision ) ) {
4518                         $old = Revision::newFromTitle( $this, (int)$old );
4519                 }
4520                 if ( !( $new instanceof Revision ) ) {
4521                         $new = Revision::newFromTitle( $this, (int)$new );
4522                 }
4523                 // XXX: what if Revision objects are passed in, but they don't refer to this title?
4524                 // Add $old->getPage() != $new->getPage() || $old->getPage() != $this->getArticleID()
4525                 // in the sanity check below?
4526                 if ( !$old || !$new ) {
4527                         return null; // nothing to compare
4528                 }
4529                 $authors = [];
4530                 $old_cmp = '>';
4531                 $new_cmp = '<';
4532                 $options = (array)$options;
4533                 if ( in_array( 'include_old', $options ) ) {
4534                         $old_cmp = '>=';
4535                 }
4536                 if ( in_array( 'include_new', $options ) ) {
4537                         $new_cmp = '<=';
4538                 }
4539                 if ( in_array( 'include_both', $options ) ) {
4540                         $old_cmp = '>=';
4541                         $new_cmp = '<=';
4542                 }
4543                 // No DB query needed if $old and $new are the same or successive revisions:
4544                 if ( $old->getId() === $new->getId() ) {
4545                         return ( $old_cmp === '>' && $new_cmp === '<' ) ?
4546                                 [] :
4547                                 [ $old->getUserText( Revision::RAW ) ];
4548                 } elseif ( $old->getId() === $new->getParentId() ) {
4549                         if ( $old_cmp === '>=' && $new_cmp === '<=' ) {
4550                                 $authors[] = $old->getUserText( Revision::RAW );
4551                                 if ( $old->getUserText( Revision::RAW ) != $new->getUserText( Revision::RAW ) ) {
4552                                         $authors[] = $new->getUserText( Revision::RAW );
4553                                 }
4554                         } elseif ( $old_cmp === '>=' ) {
4555                                 $authors[] = $old->getUserText( Revision::RAW );
4556                         } elseif ( $new_cmp === '<=' ) {
4557                                 $authors[] = $new->getUserText( Revision::RAW );
4558                         }
4559                         return $authors;
4560                 }
4561                 $dbr = wfGetDB( DB_REPLICA );
4562                 $revQuery = Revision::getQueryInfo();
4563                 $authors = $dbr->selectFieldValues(
4564                         $revQuery['tables'],
4565                         $revQuery['fields']['rev_user_text'],
4566                         [
4567                                 'rev_page' => $this->getArticleID(),
4568                                 "rev_timestamp $old_cmp " . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4569                                 "rev_timestamp $new_cmp " . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4570                         ], __METHOD__,
4571                         [ 'DISTINCT', 'LIMIT' => $limit + 1 ], // add one so caller knows it was truncated
4572                         $revQuery['joins']
4573                 );
4574                 return $authors;
4575         }
4576
4577         /**
4578          * Get the number of authors between the given revisions or revision IDs.
4579          * Used for diffs and other things that really need it.
4580          *
4581          * @param int|Revision $old Old revision or rev ID (first before range by default)
4582          * @param int|Revision $new New revision or rev ID (first after range by default)
4583          * @param int $limit Maximum number of authors
4584          * @param string|array $options (Optional): Single option, or an array of options:
4585          *     'include_old' Include $old in the range; $new is excluded.
4586          *     'include_new' Include $new in the range; $old is excluded.
4587          *     'include_both' Include both $old and $new in the range.
4588          *     Unknown option values are ignored.
4589          * @return int Number of revision authors in the range; zero if not both revisions exist
4590          */
4591         public function countAuthorsBetween( $old, $new, $limit, $options = [] ) {
4592                 $authors = $this->getAuthorsBetween( $old, $new, $limit, $options );
4593                 return $authors ? count( $authors ) : 0;
4594         }
4595
4596         /**
4597          * Compare with another title.
4598          *
4599          * @param Title $title
4600          * @return bool
4601          */
4602         public function equals( Title $title ) {
4603                 // Note: === is necessary for proper matching of number-like titles.
4604                 return $this->mInterwiki === $title->mInterwiki
4605                         && $this->mNamespace == $title->mNamespace
4606                         && $this->mDbkeyform === $title->mDbkeyform;
4607         }
4608
4609         /**
4610          * Check if this title is a subpage of another title
4611          *
4612          * @param Title $title
4613          * @return bool
4614          */
4615         public function isSubpageOf( Title $title ) {
4616                 return $this->mInterwiki === $title->mInterwiki
4617                         && $this->mNamespace == $title->mNamespace
4618                         && strpos( $this->mDbkeyform, $title->mDbkeyform . '/' ) === 0;
4619         }
4620
4621         /**
4622          * Check if page exists.  For historical reasons, this function simply
4623          * checks for the existence of the title in the page table, and will
4624          * thus return false for interwiki links, special pages and the like.
4625          * If you want to know if a title can be meaningfully viewed, you should
4626          * probably call the isKnown() method instead.
4627          *
4628          * @param int $flags An optional bit field; may be Title::GAID_FOR_UPDATE to check
4629          *   from master/for update
4630          * @return bool
4631          */
4632         public function exists( $flags = 0 ) {
4633                 $exists = $this->getArticleID( $flags ) != 0;
4634                 Hooks::run( 'TitleExists', [ $this, &$exists ] );
4635                 return $exists;
4636         }
4637
4638         /**
4639          * Should links to this title be shown as potentially viewable (i.e. as
4640          * "bluelinks"), even if there's no record by this title in the page
4641          * table?
4642          *
4643          * This function is semi-deprecated for public use, as well as somewhat
4644          * misleadingly named.  You probably just want to call isKnown(), which
4645          * calls this function internally.
4646          *
4647          * (ISSUE: Most of these checks are cheap, but the file existence check
4648          * can potentially be quite expensive.  Including it here fixes a lot of
4649          * existing code, but we might want to add an optional parameter to skip
4650          * it and any other expensive checks.)
4651          *
4652          * @return bool
4653          */
4654         public function isAlwaysKnown() {
4655                 $isKnown = null;
4656
4657                 /**
4658                  * Allows overriding default behavior for determining if a page exists.
4659                  * If $isKnown is kept as null, regular checks happen. If it's
4660                  * a boolean, this value is returned by the isKnown method.
4661                  *
4662                  * @since 1.20
4663                  *
4664                  * @param Title $title
4665                  * @param bool|null $isKnown
4666                  */
4667                 Hooks::run( 'TitleIsAlwaysKnown', [ $this, &$isKnown ] );
4668
4669                 if ( !is_null( $isKnown ) ) {
4670                         return $isKnown;
4671                 }
4672
4673                 if ( $this->isExternal() ) {
4674                         return true; // any interwiki link might be viewable, for all we know
4675                 }
4676
4677                 switch ( $this->mNamespace ) {
4678                         case NS_MEDIA:
4679                         case NS_FILE:
4680                                 // file exists, possibly in a foreign repo
4681                                 return (bool)wfFindFile( $this );
4682                         case NS_SPECIAL:
4683                                 // valid special page
4684                                 return MediaWikiServices::getInstance()->getSpecialPageFactory()->
4685                                         exists( $this->mDbkeyform );
4686                         case NS_MAIN:
4687                                 // selflink, possibly with fragment
4688                                 return $this->mDbkeyform == '';
4689                         case NS_MEDIAWIKI:
4690                                 // known system message
4691                                 return $this->hasSourceText() !== false;
4692                         default:
4693                                 return false;
4694                 }
4695         }
4696
4697         /**
4698          * Does this title refer to a page that can (or might) be meaningfully
4699          * viewed?  In particular, this function may be used to determine if
4700          * links to the title should be rendered as "bluelinks" (as opposed to
4701          * "redlinks" to non-existent pages).
4702          * Adding something else to this function will cause inconsistency
4703          * since LinkHolderArray calls isAlwaysKnown() and does its own
4704          * page existence check.
4705          *
4706          * @return bool
4707          */
4708         public function isKnown() {
4709                 return $this->isAlwaysKnown() || $this->exists();
4710         }
4711
4712         /**
4713          * Does this page have source text?
4714          *
4715          * @return bool
4716          */
4717         public function hasSourceText() {
4718                 if ( $this->exists() ) {
4719                         return true;
4720                 }
4721
4722                 if ( $this->mNamespace == NS_MEDIAWIKI ) {
4723                         // If the page doesn't exist but is a known system message, default
4724                         // message content will be displayed, same for language subpages-
4725                         // Use always content language to avoid loading hundreds of languages
4726                         // to get the link color.
4727                         $contLang = MediaWikiServices::getInstance()->getContentLanguage();
4728                         list( $name, ) = MessageCache::singleton()->figureMessage(
4729                                 $contLang->lcfirst( $this->getText() )
4730                         );
4731                         $message = wfMessage( $name )->inLanguage( $contLang )->useDatabase( false );
4732                         return $message->exists();
4733                 }
4734
4735                 return false;
4736         }
4737
4738         /**
4739          * Get the default (plain) message contents for an page that overrides an
4740          * interface message key.
4741          *
4742          * Primary use cases:
4743          *
4744          * - Article:
4745          *    - Show default when viewing the page. The Article::getSubstituteContent
4746          *      method displays the default message content, instead of the
4747          *      'noarticletext' placeholder message normally used.
4748          *
4749          * - EditPage:
4750          *    - Title of edit page. When creating an interface message override,
4751          *      the editor is told they are "Editing the page", instead of
4752          *      "Creating the page". (EditPage::setHeaders)
4753          *    - Edit notice. The 'translateinterface' edit notice is shown when creating
4754          *      or editing a an interface message override. (EditPage::showIntro)
4755          *    - Opening the editor. The contents of the localisation message are used
4756          *      as contents of the editor when creating a new page in the MediaWiki
4757          *      namespace. This simplifies the process for editors when "changing"
4758          *      an interface message by creating an override. (EditPage::getContentObject)
4759          *    - Showing a diff. The left-hand side of a diff when an editor is
4760          *      previewing their changes before saving the creation of a page in the
4761          *      MediaWiki namespace. (EditPage::showDiff)
4762          *    - Disallowing a save. When attempting to create a a MediaWiki-namespace
4763          *      page with the proposed content matching the interface message default,
4764          *      the save is rejected, the same way we disallow blank pages from being
4765          *      created. (EditPage::internalAttemptSave)
4766          *
4767          * - ApiEditPage:
4768          *    - Default content, when using the 'prepend' or 'append' feature.
4769          *
4770          * - SkinTemplate:
4771          *    - Label the create action as "Edit", if the page can be an override.
4772          *
4773          * @return string|bool
4774          */
4775         public function getDefaultMessageText() {
4776                 if ( $this->mNamespace != NS_MEDIAWIKI ) { // Just in case
4777                         return false;
4778                 }
4779
4780                 list( $name, $lang ) = MessageCache::singleton()->figureMessage(
4781                         MediaWikiServices::getInstance()->getContentLanguage()->lcfirst( $this->getText() )
4782                 );
4783                 $message = wfMessage( $name )->inLanguage( $lang )->useDatabase( false );
4784
4785                 if ( $message->exists() ) {
4786                         return $message->plain();
4787                 } else {
4788                         return false;
4789                 }
4790         }
4791
4792         /**
4793          * Updates page_touched for this page; called from LinksUpdate.php
4794          *
4795          * @param string|null $purgeTime [optional] TS_MW timestamp
4796          * @return bool True if the update succeeded
4797          */
4798         public function invalidateCache( $purgeTime = null ) {
4799                 if ( wfReadOnly() ) {
4800                         return false;
4801                 } elseif ( $this->mArticleID === 0 ) {
4802                         return true; // avoid gap locking if we know it's not there
4803                 }
4804
4805                 $dbw = wfGetDB( DB_MASTER );
4806                 $dbw->onTransactionPreCommitOrIdle(
4807                         function () use ( $dbw ) {
4808                                 ResourceLoaderWikiModule::invalidateModuleCache(
4809                                         $this, null, null, $dbw->getDomainId() );
4810                         },
4811                         __METHOD__
4812                 );
4813
4814                 $conds = $this->pageCond();
4815                 DeferredUpdates::addUpdate(
4816                         new AutoCommitUpdate(
4817                                 $dbw,
4818                                 __METHOD__,
4819                                 function ( IDatabase $dbw, $fname ) use ( $conds, $purgeTime ) {
4820                                         $dbTimestamp = $dbw->timestamp( $purgeTime ?: time() );
4821                                         $dbw->update(
4822                                                 'page',
4823                                                 [ 'page_touched' => $dbTimestamp ],
4824                                                 $conds + [ 'page_touched < ' . $dbw->addQuotes( $dbTimestamp ) ],
4825                                                 $fname
4826                                         );
4827                                         MediaWikiServices::getInstance()->getLinkCache()->invalidateTitle( $this );
4828                                 }
4829                         ),
4830                         DeferredUpdates::PRESEND
4831                 );
4832
4833                 return true;
4834         }
4835
4836         /**
4837          * Update page_touched timestamps and send CDN purge messages for
4838          * pages linking to this title. May be sent to the job queue depending
4839          * on the number of links. Typically called on create and delete.
4840          */
4841         public function touchLinks() {
4842                 DeferredUpdates::addUpdate( new HTMLCacheUpdate( $this, 'pagelinks', 'page-touch' ) );
4843                 if ( $this->mNamespace == NS_CATEGORY ) {
4844                         DeferredUpdates::addUpdate(
4845                                 new HTMLCacheUpdate( $this, 'categorylinks', 'category-touch' )
4846                         );
4847                 }
4848         }
4849
4850         /**
4851          * Get the last touched timestamp
4852          *
4853          * @param IDatabase|null $db
4854          * @return string|false Last-touched timestamp
4855          */
4856         public function getTouched( $db = null ) {
4857                 if ( $db === null ) {
4858                         $db = wfGetDB( DB_REPLICA );
4859                 }
4860                 $touched = $db->selectField( 'page', 'page_touched', $this->pageCond(), __METHOD__ );
4861                 return $touched;
4862         }
4863
4864         /**
4865          * Get the timestamp when this page was updated since the user last saw it.
4866          *
4867          * @param User|null $user
4868          * @return string|null
4869          */
4870         public function getNotificationTimestamp( $user = null ) {
4871                 global $wgUser;
4872
4873                 // Assume current user if none given
4874                 if ( !$user ) {
4875                         $user = $wgUser;
4876                 }
4877                 // Check cache first
4878                 $uid = $user->getId();
4879                 if ( !$uid ) {
4880                         return false;
4881                 }
4882                 // avoid isset here, as it'll return false for null entries
4883                 if ( array_key_exists( $uid, $this->mNotificationTimestamp ) ) {
4884                         return $this->mNotificationTimestamp[$uid];
4885                 }
4886                 // Don't cache too much!
4887                 if ( count( $this->mNotificationTimestamp ) >= self::CACHE_MAX ) {
4888                         $this->mNotificationTimestamp = [];
4889                 }
4890
4891                 $store = MediaWikiServices::getInstance()->getWatchedItemStore();
4892                 $watchedItem = $store->getWatchedItem( $user, $this );
4893                 if ( $watchedItem ) {
4894                         $this->mNotificationTimestamp[$uid] = $watchedItem->getNotificationTimestamp();
4895                 } else {
4896                         $this->mNotificationTimestamp[$uid] = false;
4897                 }
4898
4899                 return $this->mNotificationTimestamp[$uid];
4900         }
4901
4902         /**
4903          * Generate strings used for xml 'id' names in monobook tabs
4904          *
4905          * @param string $prepend Defaults to 'nstab-'
4906          * @return string XML 'id' name
4907          */
4908         public function getNamespaceKey( $prepend = 'nstab-' ) {
4909                 // Gets the subject namespace of this title
4910                 $subjectNS = MWNamespace::getSubject( $this->mNamespace );
4911                 // Prefer canonical namespace name for HTML IDs
4912                 $namespaceKey = MWNamespace::getCanonicalName( $subjectNS );
4913                 if ( $namespaceKey === false ) {
4914                         // Fallback to localised text
4915                         $namespaceKey = $this->getSubjectNsText();
4916                 }
4917                 // Makes namespace key lowercase
4918                 $namespaceKey = MediaWikiServices::getInstance()->getContentLanguage()->lc( $namespaceKey );
4919                 // Uses main
4920                 if ( $namespaceKey == '' ) {
4921                         $namespaceKey = 'main';
4922                 }
4923                 // Changes file to image for backwards compatibility
4924                 if ( $namespaceKey == 'file' ) {
4925                         $namespaceKey = 'image';
4926                 }
4927                 return $prepend . $namespaceKey;
4928         }
4929
4930         /**
4931          * Get all extant redirects to this Title
4932          *
4933          * @param int|null $ns Single namespace to consider; null to consider all namespaces
4934          * @return Title[] Array of Title redirects to this title
4935          */
4936         public function getRedirectsHere( $ns = null ) {
4937                 $redirs = [];
4938
4939                 $dbr = wfGetDB( DB_REPLICA );
4940                 $where = [
4941                         'rd_namespace' => $this->mNamespace,
4942                         'rd_title' => $this->mDbkeyform,
4943                         'rd_from = page_id'
4944                 ];
4945                 if ( $this->isExternal() ) {
4946                         $where['rd_interwiki'] = $this->mInterwiki;
4947                 } else {
4948                         $where[] = 'rd_interwiki = ' . $dbr->addQuotes( '' ) . ' OR rd_interwiki IS NULL';
4949                 }
4950                 if ( !is_null( $ns ) ) {
4951                         $where['page_namespace'] = $ns;
4952                 }
4953
4954                 $res = $dbr->select(
4955                         [ 'redirect', 'page' ],
4956                         [ 'page_namespace', 'page_title' ],
4957                         $where,
4958                         __METHOD__
4959                 );
4960
4961                 foreach ( $res as $row ) {
4962                         $redirs[] = self::newFromRow( $row );
4963                 }
4964                 return $redirs;
4965         }
4966
4967         /**
4968          * Check if this Title is a valid redirect target
4969          *
4970          * @return bool
4971          */
4972         public function isValidRedirectTarget() {
4973                 global $wgInvalidRedirectTargets;
4974
4975                 if ( $this->isSpecialPage() ) {
4976                         // invalid redirect targets are stored in a global array, but explicitly disallow Userlogout here
4977                         if ( $this->isSpecial( 'Userlogout' ) ) {
4978                                 return false;
4979                         }
4980
4981                         foreach ( $wgInvalidRedirectTargets as $target ) {
4982                                 if ( $this->isSpecial( $target ) ) {
4983                                         return false;
4984                                 }
4985                         }
4986                 }
4987
4988                 return true;
4989         }
4990
4991         /**
4992          * Get a backlink cache object
4993          *
4994          * @return BacklinkCache
4995          */
4996         public function getBacklinkCache() {
4997                 return BacklinkCache::get( $this );
4998         }
4999
5000         /**
5001          * Whether the magic words __INDEX__ and __NOINDEX__ function for this page.
5002          *
5003          * @return bool
5004          */
5005         public function canUseNoindex() {
5006                 global $wgExemptFromUserRobotsControl;
5007
5008                 $bannedNamespaces = $wgExemptFromUserRobotsControl ?? MWNamespace::getContentNamespaces();
5009
5010                 return !in_array( $this->mNamespace, $bannedNamespaces );
5011         }
5012
5013         /**
5014          * Returns the raw sort key to be used for categories, with the specified
5015          * prefix.  This will be fed to Collation::getSortKey() to get a
5016          * binary sortkey that can be used for actual sorting.
5017          *
5018          * @param string $prefix The prefix to be used, specified using
5019          *   {{defaultsort:}} or like [[Category:Foo|prefix]].  Empty for no
5020          *   prefix.
5021          * @return string
5022          */
5023         public function getCategorySortkey( $prefix = '' ) {
5024                 $unprefixed = $this->getText();
5025
5026                 // Anything that uses this hook should only depend
5027                 // on the Title object passed in, and should probably
5028                 // tell the users to run updateCollations.php --force
5029                 // in order to re-sort existing category relations.
5030                 Hooks::run( 'GetDefaultSortkey', [ $this, &$unprefixed ] );
5031                 if ( $prefix !== '' ) {
5032                         # Separate with a line feed, so the unprefixed part is only used as
5033                         # a tiebreaker when two pages have the exact same prefix.
5034                         # In UCA, tab is the only character that can sort above LF
5035                         # so we strip both of them from the original prefix.
5036                         $prefix = strtr( $prefix, "\n\t", '  ' );
5037                         return "$prefix\n$unprefixed";
5038                 }
5039                 return $unprefixed;
5040         }
5041
5042         /**
5043          * Returns the page language code saved in the database, if $wgPageLanguageUseDB is set
5044          * to true in LocalSettings.php, otherwise returns false. If there is no language saved in
5045          * the db, it will return NULL.
5046          *
5047          * @return string|null|bool
5048          */
5049         private function getDbPageLanguageCode() {
5050                 global $wgPageLanguageUseDB;
5051
5052                 // check, if the page language could be saved in the database, and if so and
5053                 // the value is not requested already, lookup the page language using LinkCache
5054                 if ( $wgPageLanguageUseDB && $this->mDbPageLanguage === false ) {
5055                         $linkCache = MediaWikiServices::getInstance()->getLinkCache();
5056                         $linkCache->addLinkObj( $this );
5057                         $this->mDbPageLanguage = $linkCache->getGoodLinkFieldObj( $this, 'lang' );
5058                 }
5059
5060                 return $this->mDbPageLanguage;
5061         }
5062
5063         /**
5064          * Get the language in which the content of this page is written in
5065          * wikitext. Defaults to content language, but in certain cases it can be
5066          * e.g. $wgLang (such as special pages, which are in the user language).
5067          *
5068          * @since 1.18
5069          * @return Language
5070          */
5071         public function getPageLanguage() {
5072                 global $wgLang, $wgLanguageCode;
5073                 if ( $this->isSpecialPage() ) {
5074                         // special pages are in the user language
5075                         return $wgLang;
5076                 }
5077
5078                 // Checking if DB language is set
5079                 $dbPageLanguage = $this->getDbPageLanguageCode();
5080                 if ( $dbPageLanguage ) {
5081                         return wfGetLangObj( $dbPageLanguage );
5082                 }
5083
5084                 if ( !$this->mPageLanguage || $this->mPageLanguage[1] !== $wgLanguageCode ) {
5085                         // Note that this may depend on user settings, so the cache should
5086                         // be only per-request.
5087                         // NOTE: ContentHandler::getPageLanguage() may need to load the
5088                         // content to determine the page language!
5089                         // Checking $wgLanguageCode hasn't changed for the benefit of unit
5090                         // tests.
5091                         $contentHandler = ContentHandler::getForTitle( $this );
5092                         $langObj = $contentHandler->getPageLanguage( $this );
5093                         $this->mPageLanguage = [ $langObj->getCode(), $wgLanguageCode ];
5094                 } else {
5095                         $langObj = Language::factory( $this->mPageLanguage[0] );
5096                 }
5097
5098                 return $langObj;
5099         }
5100
5101         /**
5102          * Get the language in which the content of this page is written when
5103          * viewed by user. Defaults to content language, but in certain cases it can be
5104          * e.g. $wgLang (such as special pages, which are in the user language).
5105          *
5106          * @since 1.20
5107          * @return Language
5108          */
5109         public function getPageViewLanguage() {
5110                 global $wgLang;
5111
5112                 if ( $this->isSpecialPage() ) {
5113                         // If the user chooses a variant, the content is actually
5114                         // in a language whose code is the variant code.
5115                         $variant = $wgLang->getPreferredVariant();
5116                         if ( $wgLang->getCode() !== $variant ) {
5117                                 return Language::factory( $variant );
5118                         }
5119
5120                         return $wgLang;
5121                 }
5122
5123                 // Checking if DB language is set
5124                 $dbPageLanguage = $this->getDbPageLanguageCode();
5125                 if ( $dbPageLanguage ) {
5126                         $pageLang = wfGetLangObj( $dbPageLanguage );
5127                         $variant = $pageLang->getPreferredVariant();
5128                         if ( $pageLang->getCode() !== $variant ) {
5129                                 $pageLang = Language::factory( $variant );
5130                         }
5131
5132                         return $pageLang;
5133                 }
5134
5135                 // @note Can't be cached persistently, depends on user settings.
5136                 // @note ContentHandler::getPageViewLanguage() may need to load the
5137                 //   content to determine the page language!
5138                 $contentHandler = ContentHandler::getForTitle( $this );
5139                 $pageLang = $contentHandler->getPageViewLanguage( $this );
5140                 return $pageLang;
5141         }
5142
5143         /**
5144          * Get a list of rendered edit notices for this page.
5145          *
5146          * Array is keyed by the original message key, and values are rendered using parseAsBlock, so
5147          * they will already be wrapped in paragraphs.
5148          *
5149          * @since 1.21
5150          * @param int $oldid Revision ID that's being edited
5151          * @return array
5152          */
5153         public function getEditNotices( $oldid = 0 ) {
5154                 $notices = [];
5155
5156                 // Optional notice for the entire namespace
5157                 $editnotice_ns = 'editnotice-' . $this->mNamespace;
5158                 $msg = wfMessage( $editnotice_ns );
5159                 if ( $msg->exists() ) {
5160                         $html = $msg->parseAsBlock();
5161                         // Edit notices may have complex logic, but output nothing (T91715)
5162                         if ( trim( $html ) !== '' ) {
5163                                 $notices[$editnotice_ns] = Html::rawElement(
5164                                         'div',
5165                                         [ 'class' => [
5166                                                 'mw-editnotice',
5167                                                 'mw-editnotice-namespace',
5168                                                 Sanitizer::escapeClass( "mw-$editnotice_ns" )
5169                                         ] ],
5170                                         $html
5171                                 );
5172                         }
5173                 }
5174
5175                 if ( MWNamespace::hasSubpages( $this->mNamespace ) ) {
5176                         // Optional notice for page itself and any parent page
5177                         $editnotice_base = $editnotice_ns;
5178                         foreach ( explode( '/', $this->mDbkeyform ) as $part ) {
5179                                 $editnotice_base .= '-' . $part;
5180                                 $msg = wfMessage( $editnotice_base );
5181                                 if ( $msg->exists() ) {
5182                                         $html = $msg->parseAsBlock();
5183                                         if ( trim( $html ) !== '' ) {
5184                                                 $notices[$editnotice_base] = Html::rawElement(
5185                                                         'div',
5186                                                         [ 'class' => [
5187                                                                 'mw-editnotice',
5188                                                                 'mw-editnotice-base',
5189                                                                 Sanitizer::escapeClass( "mw-$editnotice_base" )
5190                                                         ] ],
5191                                                         $html
5192                                                 );
5193                                         }
5194                                 }
5195                         }
5196                 } else {
5197                         // Even if there are no subpages in namespace, we still don't want "/" in MediaWiki message keys
5198                         $editnoticeText = $editnotice_ns . '-' . strtr( $this->mDbkeyform, '/', '-' );
5199                         $msg = wfMessage( $editnoticeText );
5200                         if ( $msg->exists() ) {
5201                                 $html = $msg->parseAsBlock();
5202                                 if ( trim( $html ) !== '' ) {
5203                                         $notices[$editnoticeText] = Html::rawElement(
5204                                                 'div',
5205                                                 [ 'class' => [
5206                                                         'mw-editnotice',
5207                                                         'mw-editnotice-page',
5208                                                         Sanitizer::escapeClass( "mw-$editnoticeText" )
5209                                                 ] ],
5210                                                 $html
5211                                         );
5212                                 }
5213                         }
5214                 }
5215
5216                 Hooks::run( 'TitleGetEditNotices', [ $this, $oldid, &$notices ] );
5217                 return $notices;
5218         }
5219
5220         /**
5221          * @return array
5222          */
5223         public function __sleep() {
5224                 return [
5225                         'mNamespace',
5226                         'mDbkeyform',
5227                         'mFragment',
5228                         'mInterwiki',
5229                         'mLocalInterwiki',
5230                         'mUserCaseDBKey',
5231                         'mDefaultNamespace',
5232                 ];
5233         }
5234
5235         public function __wakeup() {
5236                 $this->mArticleID = ( $this->mNamespace >= 0 ) ? -1 : 0;
5237                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
5238                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
5239         }
5240
5241 }