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 use MediaWiki\Linker\LinkTarget;
  25 use MediaWiki\Interwiki\InterwikiLookup;
  26 use MediaWiki\MediaWikiServices;
  27
  28 /**
  29  * Represents a title within MediaWiki.
  30  * Optionally may contain an interwiki designation or namespace.
  31  * @note This class can fetch various kinds of data from the database;
  32  *       however, it does so inefficiently.
  33  * @note Consider using a TitleValue object instead. TitleValue is more lightweight
  34  *       and does not rely on global state or the database.
  35  */
  36 class Title implements LinkTarget {
  37         /** @var HashBagOStuff */
  38         static private $titleCache = null;
  39
  40         /**
  41          * Title::newFromText maintains a cache to avoid expensive re-normalization of
  42          * commonly used titles. On a batch operation this can become a memory leak
  43          * if not bounded. After hitting this many titles reset the cache.
  44          */
  45         const CACHE_MAX = 1000;
  46
  47         /**
  48          * Used to be GAID_FOR_UPDATE define. Used with getArticleID() and friends
  49          * to use the master DB
  50          */
  51         const GAID_FOR_UPDATE = 1;
  52
  53         /**
  54          * @name Private member variables
  55          * Please use the accessor functions instead.
  56          * @private
  57          */
  58         // @{
  59
  60         /** @var string Text form (spaces not underscores) of the main part */
  61         public $mTextform = '';
  62
  63         /** @var string URL-encoded form of the main part */
  64         public $mUrlform = '';
  65
  66         /** @var string Main part with underscores */
  67         public $mDbkeyform = '';
  68
  69         /** @var string Database key with the initial letter in the case specified by the user */
  70         protected $mUserCaseDBKey;
  71
  72         /** @var int Namespace index, i.e. one of the NS_xxxx constants */
  73         public $mNamespace = NS_MAIN;
  74
  75         /** @var string Interwiki prefix */
  76         public $mInterwiki = '';
  77
  78         /** @var bool Was this Title created from a string with a local interwiki prefix? */
  79         private $mLocalInterwiki = false;
  80
  81         /** @var string Title fragment (i.e. the bit after the #) */
  82         public $mFragment = '';
  83
  84         /** @var int Article ID, fetched from the link cache on demand */
  85         public $mArticleID = -1;
  86
  87         /** @var bool|int ID of most recent revision */
  88         protected $mLatestID = false;
  89
  90         /**
  91          * @var bool|string ID of the page's content model, i.e. one of the
  92          *   CONTENT_MODEL_XXX constants
  93          */
  94         private $mContentModel = false;
  95
  96         /**
  97          * @var bool If a content model was forced via setContentModel()
  98          *   this will be true to avoid having other code paths reset it
  99          */
 100         private $mForcedContentModel = false;
 101
 102         /** @var int Estimated number of revisions; null of not loaded */
 103         private $mEstimateRevisions;
 104
 105         /** @var array Array of groups allowed to edit this article */
 106         public $mRestrictions = [];
 107
 108         /** @var string|bool */
 109         protected $mOldRestrictions = false;
 110
 111         /** @var bool Cascade restrictions on this page to included templates and images? */
 112         public $mCascadeRestriction;
 113
 114         /** Caching the results of getCascadeProtectionSources */
 115         public $mCascadingRestrictions;
 116
 117         /** @var array When do the restrictions on this page expire? */
 118         protected $mRestrictionsExpiry = [];
 119
 120         /** @var bool Are cascading restrictions in effect on this page? */
 121         protected $mHasCascadingRestrictions;
 122
 123         /** @var array Where are the cascading restrictions coming from on this page? */
 124         public $mCascadeSources;
 125
 126         /** @var bool Boolean for initialisation on demand */
 127         public $mRestrictionsLoaded = false;
 128
 129         /** @var string Text form including namespace/interwiki, initialised on demand */
 130         protected $mPrefixedText = null;
 131
 132         /** @var mixed Cached value for getTitleProtection (create protection) */
 133         public $mTitleProtection;
 134
 135         /**
 136          * @var int Namespace index when there is no namespace. Don't change the
 137          *   following default, NS_MAIN is hardcoded in several places. See T2696.
 138          *   Zero except in {{transclusion}} tags.
 139          */
 140         public $mDefaultNamespace = NS_MAIN;
 141
 142         /** @var int The page length, 0 for special pages */
 143         protected $mLength = -1;
 144
 145         /** @var null Is the article at this title a redirect? */
 146         public $mRedirect = null;
 147
 148         /** @var array Associative array of user ID -> timestamp/false */
 149         private $mNotificationTimestamp = [];
 150
 151         /** @var bool Whether a page has any subpages */
 152         private $mHasSubpages;
 153
 154         /** @var bool The (string) language code of the page's language and content code. */
 155         private $mPageLanguage = false;
 156
 157         /** @var string|bool|null The page language code from the database, null if not saved in
 158          * the database or false if not loaded, yet. */
 159         private $mDbPageLanguage = false;
 160
 161         /** @var TitleValue A corresponding TitleValue object */
 162         private $mTitleValue = null;
 163
 164         /** @var bool Would deleting this page be a big deletion? */
 165         private $mIsBigDeletion = null;
 166         // @}
 167
 168         /**
 169          * B/C kludge: provide a TitleParser for use by Title.
 170          * Ideally, Title would have no methods that need this.
 171          * Avoid usage of this singleton by using TitleValue
 172          * and the associated services when possible.
 173          *
 174          * @return TitleFormatter
 175          */
 176         private static function getTitleFormatter() {
 177                 return MediaWikiServices::getInstance()->getTitleFormatter();
 178         }
 179
 180         /**
 181          * B/C kludge: provide an InterwikiLookup for use by Title.
 182          * Ideally, Title would have no methods that need this.
 183          * Avoid usage of this singleton by using TitleValue
 184          * and the associated services when possible.
 185          *
 186          * @return InterwikiLookup
 187          */
 188         private static function getInterwikiLookup() {
 189                 return MediaWikiServices::getInstance()->getInterwikiLookup();
 190         }
 191
 192         /**
 193          * @access protected
 194          */
 195         function __construct() {
 196         }
 197
 198         /**
 199          * Create a new Title from a prefixed DB key
 200          *
 201          * @param string $key The database key, which has underscores
 202          *      instead of spaces, possibly including namespace and
 203          *      interwiki prefixes
 204          * @return Title|null Title, or null on an error
 205          */
 206         public static function newFromDBkey( $key ) {
 207                 $t = new Title();
 208                 $t->mDbkeyform = $key;
 209
 210                 try {
 211                         $t->secureAndSplit();
 212                         return $t;
 213                 } catch ( MalformedTitleException $ex ) {
 214                         return null;
 215                 }
 216         }
 217
 218         /**
 219          * Create a new Title from a TitleValue
 220          *
 221          * @param TitleValue $titleValue Assumed to be safe.
 222          *
 223          * @return Title
 224          */
 225         public static function newFromTitleValue( TitleValue $titleValue ) {
 226                 return self::newFromLinkTarget( $titleValue );
 227         }
 228
 229         /**
 230          * Create a new Title from a LinkTarget
 231          *
 232          * @param LinkTarget $linkTarget Assumed to be safe.
 233          *
 234          * @return Title
 235          */
 236         public static function newFromLinkTarget( LinkTarget $linkTarget ) {
 237                 if ( $linkTarget instanceof Title ) {
 238                         // Special case if it's already a Title object
 239                         return $linkTarget;
 240                 }
 241                 return self::makeTitle(
 242                         $linkTarget->getNamespace(),
 243                         $linkTarget->getText(),
 244                         $linkTarget->getFragment(),
 245                         $linkTarget->getInterwiki()
 246                 );
 247         }
 248
 249         /**
 250          * Create a new Title from text, such as what one would find in a link. De-
 251          * codes any HTML entities in the text.
 252          *
 253          * @param string|int|null $text The link text; spaces, prefixes, and an
 254          *   initial ':' indicating the main namespace are accepted.
 255          * @param int $defaultNamespace The namespace to use if none is specified
 256          *   by a prefix.  If you want to force a specific namespace even if
 257          *   $text might begin with a namespace prefix, use makeTitle() or
 258          *   makeTitleSafe().
 259          * @throws InvalidArgumentException
 260          * @return Title|null Title or null on an error.
 261          */
 262         public static function newFromText( $text, $defaultNamespace = NS_MAIN ) {
 263                 // DWIM: Integers can be passed in here when page titles are used as array keys.
 264                 if ( $text !== null && !is_string( $text ) && !is_int( $text ) ) {
 265                         throw new InvalidArgumentException( '$text must be a string.' );
 266                 }
 267                 if ( $text === null ) {
 268                         return null;
 269                 }
 270
 271                 try {
 272                         return Title::newFromTextThrow( strval( $text ), $defaultNamespace );
 273                 } catch ( MalformedTitleException $ex ) {
 274                         return null;
 275                 }
 276         }
 277
 278         /**
 279          * Like Title::newFromText(), but throws MalformedTitleException when the title is invalid,
 280          * rather than returning null.
 281          *
 282          * The exception subclasses encode detailed information about why the title is invalid.
 283          *
 284          * @see Title::newFromText
 285          *
 286          * @since 1.25
 287          * @param string $text Title text to check
 288          * @param int $defaultNamespace
 289          * @throws MalformedTitleException If the title is invalid
 290          * @return Title
 291          */
 292         public static function newFromTextThrow( $text, $defaultNamespace = NS_MAIN ) {
 293                 if ( is_object( $text ) ) {
 294                         throw new MWException( '$text must be a string, given an object' );
 295                 }
 296
 297                 $titleCache = self::getTitleCache();
 298
 299                 // Wiki pages often contain multiple links to the same page.
 300                 // Title normalization and parsing can become expensive on pages with many
 301                 // links, so we can save a little time by caching them.
 302                 // In theory these are value objects and won't get changed...
 303                 if ( $defaultNamespace == NS_MAIN ) {
 304                         $t = $titleCache->get( $text );
 305                         if ( $t ) {
 306                                 return $t;
 307                         }
 308                 }
 309
 310                 // Convert things like &eacute; &#257; or &#x3017; into normalized (T16952) text
 311                 $filteredText = Sanitizer::decodeCharReferencesAndNormalize( $text );
 312
 313                 $t = new Title();
 314                 $t->mDbkeyform = strtr( $filteredText, ' ', '_' );
 315                 $t->mDefaultNamespace = intval( $defaultNamespace );
 316
 317                 $t->secureAndSplit();
 318                 if ( $defaultNamespace == NS_MAIN ) {
 319                         $titleCache->set( $text, $t );
 320                 }
 321                 return $t;
 322         }
 323
 324         /**
 325          * THIS IS NOT THE FUNCTION YOU WANT. Use Title::newFromText().
 326          *
 327          * Example of wrong and broken code:
 328          * $title = Title::newFromURL( $wgRequest->getVal( 'title' ) );
 329          *
 330          * Example of right code:
 331          * $title = Title::newFromText( $wgRequest->getVal( 'title' ) );
 332          *
 333          * Create a new Title from URL-encoded text. Ensures that
 334          * the given title's length does not exceed the maximum.
 335          *
 336          * @param string $url The title, as might be taken from a URL
 337          * @return Title|null The new object, or null on an error
 338          */
 339         public static function newFromURL( $url ) {
 340                 $t = new Title();
 341
 342                 # For compatibility with old buggy URLs. "+" is usually not valid in titles,
 343                 # but some URLs used it as a space replacement and they still come
 344                 # from some external search tools.
 345                 if ( strpos( self::legalChars(), '+' ) === false ) {
 346                         $url = strtr( $url, '+', ' ' );
 347                 }
 348
 349                 $t->mDbkeyform = strtr( $url, ' ', '_' );
 350
 351                 try {
 352                         $t->secureAndSplit();
 353                         return $t;
 354                 } catch ( MalformedTitleException $ex ) {
 355                         return null;
 356                 }
 357         }
 358
 359         /**
 360          * @return HashBagOStuff
 361          */
 362         private static function getTitleCache() {
 363                 if ( self::$titleCache == null ) {
 364                         self::$titleCache = new HashBagOStuff( [ 'maxKeys' => self::CACHE_MAX ] );
 365                 }
 366                 return self::$titleCache;
 367         }
 368
 369         /**
 370          * Returns a list of fields that are to be selected for initializing Title
 371          * objects or LinkCache entries. Uses $wgContentHandlerUseDB to determine
 372          * whether to include page_content_model.
 373          *
 374          * @return array
 375          */
 376         protected static function getSelectFields() {
 377                 global $wgContentHandlerUseDB, $wgPageLanguageUseDB;
 378
 379                 $fields = [
 380                         'page_namespace', 'page_title', 'page_id',
 381                         'page_len', 'page_is_redirect', 'page_latest',
 382                 ];
 383
 384                 if ( $wgContentHandlerUseDB ) {
 385                         $fields[] = 'page_content_model';
 386                 }
 387
 388                 if ( $wgPageLanguageUseDB ) {
 389                         $fields[] = 'page_lang';
 390                 }
 391
 392                 return $fields;
 393         }
 394
 395         /**
 396          * Create a new Title from an article ID
 397          *
 398          * @param int $id The page_id corresponding to the Title to create
 399          * @param int $flags Use Title::GAID_FOR_UPDATE to use master
 400          * @return Title|null The new object, or null on an error
 401          */
 402         public static function newFromID( $id, $flags = 0 ) {
 403                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_REPLICA );
 404                 $row = $db->selectRow(
 405                         'page',
 406                         self::getSelectFields(),
 407                         [ 'page_id' => $id ],
 408                         __METHOD__
 409                 );
 410                 if ( $row !== false ) {
 411                         $title = Title::newFromRow( $row );
 412                 } else {
 413                         $title = null;
 414                 }
 415                 return $title;
 416         }
 417
 418         /**
 419          * Make an array of titles from an array of IDs
 420          *
 421          * @param int[] $ids Array of IDs
 422          * @return Title[] Array of Titles
 423          */
 424         public static function newFromIDs( $ids ) {
 425                 if ( !count( $ids ) ) {
 426                         return [];
 427                 }
 428                 $dbr = wfGetDB( DB_REPLICA );
 429
 430                 $res = $dbr->select(
 431                         'page',
 432                         self::getSelectFields(),
 433                         [ 'page_id' => $ids ],
 434                         __METHOD__
 435                 );
 436
 437                 $titles = [];
 438                 foreach ( $res as $row ) {
 439                         $titles[] = Title::newFromRow( $row );
 440                 }
 441                 return $titles;
 442         }
 443
 444         /**
 445          * Make a Title object from a DB row
 446          *
 447          * @param stdClass $row Object database row (needs at least page_title,page_namespace)
 448          * @return Title Corresponding Title
 449          */
 450         public static function newFromRow( $row ) {
 451                 $t = self::makeTitle( $row->page_namespace, $row->page_title );
 452                 $t->loadFromRow( $row );
 453                 return $t;
 454         }
 455
 456         /**
 457          * Load Title object fields from a DB row.
 458          * If false is given, the title will be treated as non-existing.
 459          *
 460          * @param stdClass|bool $row Database row
 461          */
 462         public function loadFromRow( $row ) {
 463                 if ( $row ) { // page found
 464                         if ( isset( $row->page_id ) ) {
 465                                 $this->mArticleID = (int)$row->page_id;
 466                         }
 467                         if ( isset( $row->page_len ) ) {
 468                                 $this->mLength = (int)$row->page_len;
 469                         }
 470                         if ( isset( $row->page_is_redirect ) ) {
 471                                 $this->mRedirect = (bool)$row->page_is_redirect;
 472                         }
 473                         if ( isset( $row->page_latest ) ) {
 474                                 $this->mLatestID = (int)$row->page_latest;
 475                         }
 476                         if ( !$this->mForcedContentModel && isset( $row->page_content_model ) ) {
 477                                 $this->mContentModel = strval( $row->page_content_model );
 478                         } elseif ( !$this->mForcedContentModel ) {
 479                                 $this->mContentModel = false; # initialized lazily in getContentModel()
 480                         }
 481                         if ( isset( $row->page_lang ) ) {
 482                                 $this->mDbPageLanguage = (string)$row->page_lang;
 483                         }
 484                         if ( isset( $row->page_restrictions ) ) {
 485                                 $this->mOldRestrictions = $row->page_restrictions;
 486                         }
 487                 } else { // page not found
 488                         $this->mArticleID = 0;
 489                         $this->mLength = 0;
 490                         $this->mRedirect = false;
 491                         $this->mLatestID = 0;
 492                         if ( !$this->mForcedContentModel ) {
 493                                 $this->mContentModel = false; # initialized lazily in getContentModel()
 494                         }
 495                 }
 496         }
 497
 498         /**
 499          * Create a new Title from a namespace index and a DB key.
 500          * It's assumed that $ns and $title are *valid*, for instance when
 501          * they came directly from the database or a special page name.
 502          * For convenience, spaces are converted to underscores so that
 503          * eg user_text fields can be used directly.
 504          *
 505          * @param int $ns The namespace of the article
 506          * @param string $title The unprefixed database key form
 507          * @param string $fragment The link fragment (after the "#")
 508          * @param string $interwiki The interwiki prefix
 509          * @return Title The new object
 510          */
 511         public static function makeTitle( $ns, $title, $fragment = '', $interwiki = '' ) {
 512                 $t = new Title();
 513                 $t->mInterwiki = $interwiki;
 514                 $t->mFragment = $fragment;
 515                 $t->mNamespace = $ns = intval( $ns );
 516                 $t->mDbkeyform = strtr( $title, ' ', '_' );
 517                 $t->mArticleID = ( $ns >= 0 ) ? -1 : 0;
 518                 $t->mUrlform = wfUrlencode( $t->mDbkeyform );
 519                 $t->mTextform = strtr( $title, '_', ' ' );
 520                 $t->mContentModel = false; # initialized lazily in getContentModel()
 521                 return $t;
 522         }
 523
 524         /**
 525          * Create a new Title from a namespace index and a DB key.
 526          * The parameters will be checked for validity, which is a bit slower
 527          * than makeTitle() but safer for user-provided data.
 528          *
 529          * @param int $ns The namespace of the article
 530          * @param string $title Database key form
 531          * @param string $fragment The link fragment (after the "#")
 532          * @param string $interwiki Interwiki prefix
 533          * @return Title|null The new object, or null on an error
 534          */
 535         public static function makeTitleSafe( $ns, $title, $fragment = '', $interwiki = '' ) {
 536                 if ( !MWNamespace::exists( $ns ) ) {
 537                         return null;
 538                 }
 539
 540                 $t = new Title();
 541                 $t->mDbkeyform = Title::makeName( $ns, $title, $fragment, $interwiki, true );
 542
 543                 try {
 544                         $t->secureAndSplit();
 545                         return $t;
 546                 } catch ( MalformedTitleException $ex ) {
 547                         return null;
 548                 }
 549         }
 550
 551         /**
 552          * Create a new Title for the Main Page
 553          *
 554          * @return Title The new object
 555          */
 556         public static function newMainPage() {
 557                 $title = Title::newFromText( wfMessage( 'mainpage' )->inContentLanguage()->text() );
 558                 // Don't give fatal errors if the message is broken
 559                 if ( !$title ) {
 560                         $title = Title::newFromText( 'Main Page' );
 561                 }
 562                 return $title;
 563         }
 564
 565         /**
 566          * Get the prefixed DB key associated with an ID
 567          *
 568          * @param int $id The page_id of the article
 569          * @return Title|null An object representing the article, or null if no such article was found
 570          */
 571         public static function nameOf( $id ) {
 572                 $dbr = wfGetDB( DB_REPLICA );
 573
 574                 $s = $dbr->selectRow(
 575                         'page',
 576                         [ 'page_namespace', 'page_title' ],
 577                         [ 'page_id' => $id ],
 578                         __METHOD__
 579                 );
 580                 if ( $s === false ) {
 581                         return null;
 582                 }
 583
 584                 $n = self::makeName( $s->page_namespace, $s->page_title );
 585                 return $n;
 586         }
 587
 588         /**
 589          * Get a regex character class describing the legal characters in a link
 590          *
 591          * @return string The list of characters, not delimited
 592          */
 593         public static function legalChars() {
 594                 global $wgLegalTitleChars;
 595                 return $wgLegalTitleChars;
 596         }
 597
 598         /**
 599          * Returns a simple regex that will match on characters and sequences invalid in titles.
 600          * Note that this doesn't pick up many things that could be wrong with titles, but that
 601          * replacing this regex with something valid will make many titles valid.
 602          *
 603          * @deprecated since 1.25, use MediaWikiTitleCodec::getTitleInvalidRegex() instead
 604          *
 605          * @return string Regex string
 606          */
 607         static function getTitleInvalidRegex() {
 608                 wfDeprecated( __METHOD__, '1.25' );
 609                 return MediaWikiTitleCodec::getTitleInvalidRegex();
 610         }
 611
 612         /**
 613          * Utility method for converting a character sequence from bytes to Unicode.
 614          *
 615          * Primary usecase being converting $wgLegalTitleChars to a sequence usable in
 616          * javascript, as PHP uses UTF-8 bytes where javascript uses Unicode code units.
 617          *
 618          * @param string $byteClass
 619          * @return string
 620          */
 621         public static function convertByteClassToUnicodeClass( $byteClass ) {
 622                 $length = strlen( $byteClass );
 623                 // Input token queue
 624                 $x0 = $x1 = $x2 = '';
 625                 // Decoded queue
 626                 $d0 = $d1 = $d2 = '';
 627                 // Decoded integer codepoints
 628                 $ord0 = $ord1 = $ord2 = 0;
 629                 // Re-encoded queue
 630                 $r0 = $r1 = $r2 = '';
 631                 // Output
 632                 $out = '';
 633                 // Flags
 634                 $allowUnicode = false;
 635                 for ( $pos = 0; $pos < $length; $pos++ ) {
 636                         // Shift the queues down
 637                         $x2 = $x1;
 638                         $x1 = $x0;
 639                         $d2 = $d1;
 640                         $d1 = $d0;
 641                         $ord2 = $ord1;
 642                         $ord1 = $ord0;
 643                         $r2 = $r1;
 644                         $r1 = $r0;
 645                         // Load the current input token and decoded values
 646                         $inChar = $byteClass[$pos];
 647                         if ( $inChar == '\\' ) {
 648                                 if ( preg_match( '/x([0-9a-fA-F]{2})/A', $byteClass, $m, 0, $pos + 1 ) ) {
 649                                         $x0 = $inChar . $m[0];
 650                                         $d0 = chr( hexdec( $m[1] ) );
 651                                         $pos += strlen( $m[0] );
 652                                 } elseif ( preg_match( '/[0-7]{3}/A', $byteClass, $m, 0, $pos + 1 ) ) {
 653                                         $x0 = $inChar . $m[0];
 654                                         $d0 = chr( octdec( $m[0] ) );
 655                                         $pos += strlen( $m[0] );
 656                                 } elseif ( $pos + 1 >= $length ) {
 657                                         $x0 = $d0 = '\\';
 658                                 } else {
 659                                         $d0 = $byteClass[$pos + 1];
 660                                         $x0 = $inChar . $d0;
 661                                         $pos += 1;
 662                                 }
 663                         } else {
 664                                 $x0 = $d0 = $inChar;
 665                         }
 666                         $ord0 = ord( $d0 );
 667                         // Load the current re-encoded value
 668                         if ( $ord0 < 32 || $ord0 == 0x7f ) {
 669                                 $r0 = sprintf( '\x%02x', $ord0 );
 670                         } elseif ( $ord0 >= 0x80 ) {
 671                                 // Allow unicode if a single high-bit character appears
 672                                 $r0 = sprintf( '\x%02x', $ord0 );
 673                                 $allowUnicode = true;
 674                         } elseif ( strpos( '-\\[]^', $d0 ) !== false ) {
 675                                 $r0 = '\\' . $d0;
 676                         } else {
 677                                 $r0 = $d0;
 678                         }
 679                         // Do the output
 680                         if ( $x0 !== '' && $x1 === '-' && $x2 !== '' ) {
 681                                 // Range
 682                                 if ( $ord2 > $ord0 ) {
 683                                         // Empty range
 684                                 } elseif ( $ord0 >= 0x80 ) {
 685                                         // Unicode range
 686                                         $allowUnicode = true;
 687                                         if ( $ord2 < 0x80 ) {
 688                                                 // Keep the non-unicode section of the range
 689                                                 $out .= "$r2-\\x7F";
 690                                         }
 691                                 } else {
 692                                         // Normal range
 693                                         $out .= "$r2-$r0";
 694                                 }
 695                                 // Reset state to the initial value
 696                                 $x0 = $x1 = $d0 = $d1 = $r0 = $r1 = '';
 697                         } elseif ( $ord2 < 0x80 ) {
 698                                 // ASCII character
 699                                 $out .= $r2;
 700                         }
 701                 }
 702                 if ( $ord1 < 0x80 ) {
 703                         $out .= $r1;
 704                 }
 705                 if ( $ord0 < 0x80 ) {
 706                         $out .= $r0;
 707                 }
 708                 if ( $allowUnicode ) {
 709                         $out .= '\u0080-\uFFFF';
 710                 }
 711                 return $out;
 712         }
 713
 714         /**
 715          * Make a prefixed DB key from a DB key and a namespace index
 716          *
 717          * @param int $ns Numerical representation of the namespace
 718          * @param string $title The DB key form the title
 719          * @param string $fragment The link fragment (after the "#")
 720          * @param string $interwiki The interwiki prefix
 721          * @param bool $canonicalNamespace If true, use the canonical name for
 722          *   $ns instead of the localized version.
 723          * @return string The prefixed form of the title
 724          */
 725         public static function makeName( $ns, $title, $fragment = '', $interwiki = '',
 726                 $canonicalNamespace = false
 727         ) {
 728                 global $wgContLang;
 729
 730                 if ( $canonicalNamespace ) {
 731                         $namespace = MWNamespace::getCanonicalName( $ns );
 732                 } else {
 733                         $namespace = $wgContLang->getNsText( $ns );
 734                 }
 735                 $name = $namespace == '' ? $title : "$namespace:$title";
 736                 if ( strval( $interwiki ) != '' ) {
 737                         $name = "$interwiki:$name";
 738                 }
 739                 if ( strval( $fragment ) != '' ) {
 740                         $name .= '#' . $fragment;
 741                 }
 742                 return $name;
 743         }
 744
 745         /**
 746          * Escape a text fragment, say from a link, for a URL
 747          *
 748          * @param string $fragment Containing a URL or link fragment (after the "#")
 749          * @return string Escaped string
 750          */
 751         static function escapeFragmentForURL( $fragment ) {
 752                 # Note that we don't urlencode the fragment.  urlencoded Unicode
 753                 # fragments appear not to work in IE (at least up to 7) or in at least
 754                 # one version of Opera 9.x.  The W3C validator, for one, doesn't seem
 755                 # to care if they aren't encoded.
 756                 return Sanitizer::escapeId( $fragment, 'noninitial' );
 757         }
 758
 759         /**
 760          * Callback for usort() to do title sorts by (namespace, title)
 761          *
 762          * @param LinkTarget $a
 763          * @param LinkTarget $b
 764          *
 765          * @return int Result of string comparison, or namespace comparison
 766          */
 767         public static function compare( LinkTarget $a, LinkTarget $b ) {
 768                 if ( $a->getNamespace() == $b->getNamespace() ) {
 769                         return strcmp( $a->getText(), $b->getText() );
 770                 } else {
 771                         return $a->getNamespace() - $b->getNamespace();
 772                 }
 773         }
 774
 775         /**
 776          * Determine whether the object refers to a page within
 777          * this project (either this wiki or a wiki with a local
 778          * interwiki, see https://www.mediawiki.org/wiki/Manual:Interwiki_table#iw_local )
 779          *
 780          * @return bool True if this is an in-project interwiki link or a wikilink, false otherwise
 781          */
 782         public function isLocal() {
 783                 if ( $this->isExternal() ) {
 784                         $iw = self::getInterwikiLookup()->fetch( $this->mInterwiki );
 785                         if ( $iw ) {
 786                                 return $iw->isLocal();
 787                         }
 788                 }
 789                 return true;
 790         }
 791
 792         /**
 793          * Is this Title interwiki?
 794          *
 795          * @return bool
 796          */
 797         public function isExternal() {
 798                 return $this->mInterwiki !== '';
 799         }
 800
 801         /**
 802          * Get the interwiki prefix
 803          *
 804          * Use Title::isExternal to check if a interwiki is set
 805          *
 806          * @return string Interwiki prefix
 807          */
 808         public function getInterwiki() {
 809                 return $this->mInterwiki;
 810         }
 811
 812         /**
 813          * Was this a local interwiki link?
 814          *
 815          * @return bool
 816          */
 817         public function wasLocalInterwiki() {
 818                 return $this->mLocalInterwiki;
 819         }
 820
 821         /**
 822          * Determine whether the object refers to a page within
 823          * this project and is transcludable.
 824          *
 825          * @return bool True if this is transcludable
 826          */
 827         public function isTrans() {
 828                 if ( !$this->isExternal() ) {
 829                         return false;
 830                 }
 831
 832                 return self::getInterwikiLookup()->fetch( $this->mInterwiki )->isTranscludable();
 833         }
 834
 835         /**
 836          * Returns the DB name of the distant wiki which owns the object.
 837          *
 838          * @return string|false The DB name
 839          */
 840         public function getTransWikiID() {
 841                 if ( !$this->isExternal() ) {
 842                         return false;
 843                 }
 844
 845                 return self::getInterwikiLookup()->fetch( $this->mInterwiki )->getWikiID();
 846         }
 847
 848         /**
 849          * Get a TitleValue object representing this Title.
 850          *
 851          * @note Not all valid Titles have a corresponding valid TitleValue
 852          * (e.g. TitleValues cannot represent page-local links that have a
 853          * fragment but no title text).
 854          *
 855          * @return TitleValue|null
 856          */
 857         public function getTitleValue() {
 858                 if ( $this->mTitleValue === null ) {
 859                         try {
 860                                 $this->mTitleValue = new TitleValue(
 861                                         $this->getNamespace(),
 862                                         $this->getDBkey(),
 863                                         $this->getFragment(),
 864                                         $this->getInterwiki()
 865                                 );
 866                         } catch ( InvalidArgumentException $ex ) {
 867                                 wfDebug( __METHOD__ . ': Can\'t create a TitleValue for [[' .
 868                                         $this->getPrefixedText() . ']]: ' . $ex->getMessage() . "\n" );
 869                         }
 870                 }
 871
 872                 return $this->mTitleValue;
 873         }
 874
 875         /**
 876          * Get the text form (spaces not underscores) of the main part
 877          *
 878          * @return string Main part of the title
 879          */
 880         public function getText() {
 881                 return $this->mTextform;
 882         }
 883
 884         /**
 885          * Get the URL-encoded form of the main part
 886          *
 887          * @return string Main part of the title, URL-encoded
 888          */
 889         public function getPartialURL() {
 890                 return $this->mUrlform;
 891         }
 892
 893         /**
 894          * Get the main part with underscores
 895          *
 896          * @return string Main part of the title, with underscores
 897          */
 898         public function getDBkey() {
 899                 return $this->mDbkeyform;
 900         }
 901
 902         /**
 903          * Get the DB key with the initial letter case as specified by the user
 904          *
 905          * @return string DB key
 906          */
 907         function getUserCaseDBKey() {
 908                 if ( !is_null( $this->mUserCaseDBKey ) ) {
 909                         return $this->mUserCaseDBKey;
 910                 } else {
 911                         // If created via makeTitle(), $this->mUserCaseDBKey is not set.
 912                         return $this->mDbkeyform;
 913                 }
 914         }
 915
 916         /**
 917          * Get the namespace index, i.e. one of the NS_xxxx constants.
 918          *
 919          * @return int Namespace index
 920          */
 921         public function getNamespace() {
 922                 return $this->mNamespace;
 923         }
 924
 925         /**
 926          * Get the page's content model id, see the CONTENT_MODEL_XXX constants.
 927          *
 928          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
 929          * @return string Content model id
 930          */
 931         public function getContentModel( $flags = 0 ) {
 932                 if ( !$this->mForcedContentModel
 933                         && ( !$this->mContentModel || $flags === Title::GAID_FOR_UPDATE )
 934                         && $this->getArticleID( $flags )
 935                 ) {
 936                         $linkCache = LinkCache::singleton();
 937                         $linkCache->addLinkObj( $this ); # in case we already had an article ID
 938                         $this->mContentModel = $linkCache->getGoodLinkFieldObj( $this, 'model' );
 939                 }
 940
 941                 if ( !$this->mContentModel ) {
 942                         $this->mContentModel = ContentHandler::getDefaultModelFor( $this );
 943                 }
 944
 945                 return $this->mContentModel;
 946         }
 947
 948         /**
 949          * Convenience method for checking a title's content model name
 950          *
 951          * @param string $id The content model ID (use the CONTENT_MODEL_XXX constants).
 952          * @return bool True if $this->getContentModel() == $id
 953          */
 954         public function hasContentModel( $id ) {
 955                 return $this->getContentModel() == $id;
 956         }
 957
 958         /**
 959          * Set a proposed content model for the page for permissions
 960          * checking. This does not actually change the content model
 961          * of a title!
 962          *
 963          * Additionally, you should make sure you've checked
 964          * ContentHandler::canBeUsedOn() first.
 965          *
 966          * @since 1.28
 967          * @param string $model CONTENT_MODEL_XXX constant
 968          */
 969         public function setContentModel( $model ) {
 970                 $this->mContentModel = $model;
 971                 $this->mForcedContentModel = true;
 972         }
 973
 974         /**
 975          * Get the namespace text
 976          *
 977          * @return string|false Namespace text
 978          */
 979         public function getNsText() {
 980                 if ( $this->isExternal() ) {
 981                         // This probably shouldn't even happen,
 982                         // but for interwiki transclusion it sometimes does.
 983                         // Use the canonical namespaces if possible to try to
 984                         // resolve a foreign namespace.
 985                         if ( MWNamespace::exists( $this->mNamespace ) ) {
 986                                 return MWNamespace::getCanonicalName( $this->mNamespace );
 987                         }
 988                 }
 989
 990                 try {
 991                         $formatter = self::getTitleFormatter();
 992                         return $formatter->getNamespaceName( $this->mNamespace, $this->mDbkeyform );
 993                 } catch ( InvalidArgumentException $ex ) {
 994                         wfDebug( __METHOD__ . ': ' . $ex->getMessage() . "\n" );
 995                         return false;
 996                 }
 997         }
 998
 999         /**
1000          * Get the namespace text of the subject (rather than talk) page
1001          *
1002          * @return string Namespace text
1003          */
1004         public function getSubjectNsText() {
1005                 global $wgContLang;
1006                 return $wgContLang->getNsText( MWNamespace::getSubject( $this->mNamespace ) );
1007         }
1008
1009         /**
1010          * Get the namespace text of the talk page
1011          *
1012          * @return string Namespace text
1013          */
1014         public function getTalkNsText() {
1015                 global $wgContLang;
1016                 return $wgContLang->getNsText( MWNamespace::getTalk( $this->mNamespace ) );
1017         }
1018
1019         /**
1020          * Could this title have a corresponding talk page?
1021          *
1022          * @return bool
1023          */
1024         public function canTalk() {
1025                 return MWNamespace::canTalk( $this->mNamespace );
1026         }
1027
1028         /**
1029          * Is this in a namespace that allows actual pages?
1030          *
1031          * @return bool
1032          */
1033         public function canExist() {
1034                 return $this->mNamespace >= NS_MAIN;
1035         }
1036
1037         /**
1038          * Can this title be added to a user's watchlist?
1039          *
1040          * @return bool
1041          */
1042         public function isWatchable() {
1043                 return !$this->isExternal() && MWNamespace::isWatchable( $this->getNamespace() );
1044         }
1045
1046         /**
1047          * Returns true if this is a special page.
1048          *
1049          * @return bool
1050          */
1051         public function isSpecialPage() {
1052                 return $this->getNamespace() == NS_SPECIAL;
1053         }
1054
1055         /**
1056          * Returns true if this title resolves to the named special page
1057          *
1058          * @param string $name The special page name
1059          * @return bool
1060          */
1061         public function isSpecial( $name ) {
1062                 if ( $this->isSpecialPage() ) {
1063                         list( $thisName, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $this->getDBkey() );
1064                         if ( $name == $thisName ) {
1065                                 return true;
1066                         }
1067                 }
1068                 return false;
1069         }
1070
1071         /**
1072          * If the Title refers to a special page alias which is not the local default, resolve
1073          * the alias, and localise the name as necessary.  Otherwise, return $this
1074          *
1075          * @return Title
1076          */
1077         public function fixSpecialName() {
1078                 if ( $this->isSpecialPage() ) {
1079                         list( $canonicalName, $par ) = SpecialPageFactory::resolveAlias( $this->mDbkeyform );
1080                         if ( $canonicalName ) {
1081                                 $localName = SpecialPageFactory::getLocalNameFor( $canonicalName, $par );
1082                                 if ( $localName != $this->mDbkeyform ) {
1083                                         return Title::makeTitle( NS_SPECIAL, $localName );
1084                                 }
1085                         }
1086                 }
1087                 return $this;
1088         }
1089
1090         /**
1091          * Returns true if the title is inside the specified namespace.
1092          *
1093          * Please make use of this instead of comparing to getNamespace()
1094          * This function is much more resistant to changes we may make
1095          * to namespaces than code that makes direct comparisons.
1096          * @param int $ns The namespace
1097          * @return bool
1098          * @since 1.19
1099          */
1100         public function inNamespace( $ns ) {
1101                 return MWNamespace::equals( $this->getNamespace(), $ns );
1102         }
1103
1104         /**
1105          * Returns true if the title is inside one of the specified namespaces.
1106          *
1107          * @param int|int[] $namespaces,... The namespaces to check for
1108          * @return bool
1109          * @since 1.19
1110          */
1111         public function inNamespaces( /* ... */ ) {
1112                 $namespaces = func_get_args();
1113                 if ( count( $namespaces ) > 0 && is_array( $namespaces[0] ) ) {
1114                         $namespaces = $namespaces[0];
1115                 }
1116
1117                 foreach ( $namespaces as $ns ) {
1118                         if ( $this->inNamespace( $ns ) ) {
1119                                 return true;
1120                         }
1121                 }
1122
1123                 return false;
1124         }
1125
1126         /**
1127          * Returns true if the title has the same subject namespace as the
1128          * namespace specified.
1129          * For example this method will take NS_USER and return true if namespace
1130          * is either NS_USER or NS_USER_TALK since both of them have NS_USER
1131          * as their subject namespace.
1132          *
1133          * This is MUCH simpler than individually testing for equivalence
1134          * against both NS_USER and NS_USER_TALK, and is also forward compatible.
1135          * @since 1.19
1136          * @param int $ns
1137          * @return bool
1138          */
1139         public function hasSubjectNamespace( $ns ) {
1140                 return MWNamespace::subjectEquals( $this->getNamespace(), $ns );
1141         }
1142
1143         /**
1144          * Is this Title in a namespace which contains content?
1145          * In other words, is this a content page, for the purposes of calculating
1146          * statistics, etc?
1147          *
1148          * @return bool
1149          */
1150         public function isContentPage() {
1151                 return MWNamespace::isContent( $this->getNamespace() );
1152         }
1153
1154         /**
1155          * Would anybody with sufficient privileges be able to move this page?
1156          * Some pages just aren't movable.
1157          *
1158          * @return bool
1159          */
1160         public function isMovable() {
1161                 if ( !MWNamespace::isMovable( $this->getNamespace() ) || $this->isExternal() ) {
1162                         // Interwiki title or immovable namespace. Hooks don't get to override here
1163                         return false;
1164                 }
1165
1166                 $result = true;
1167                 Hooks::run( 'TitleIsMovable', [ $this, &$result ] );
1168                 return $result;
1169         }
1170
1171         /**
1172          * Is this the mainpage?
1173          * @note Title::newFromText seems to be sufficiently optimized by the title
1174          * cache that we don't need to over-optimize by doing direct comparisons and
1175          * accidentally creating new bugs where $title->equals( Title::newFromText() )
1176          * ends up reporting something differently than $title->isMainPage();
1177          *
1178          * @since 1.18
1179          * @return bool
1180          */
1181         public function isMainPage() {
1182                 return $this->equals( Title::newMainPage() );
1183         }
1184
1185         /**
1186          * Is this a subpage?
1187          *
1188          * @return bool
1189          */
1190         public function isSubpage() {
1191                 return MWNamespace::hasSubpages( $this->mNamespace )
1192                         ? strpos( $this->getText(), '/' ) !== false
1193                         : false;
1194         }
1195
1196         /**
1197          * Is this a conversion table for the LanguageConverter?
1198          *
1199          * @return bool
1200          */
1201         public function isConversionTable() {
1202                 // @todo ConversionTable should become a separate content model.
1203
1204                 return $this->getNamespace() == NS_MEDIAWIKI &&
1205                         strpos( $this->getText(), 'Conversiontable/' ) === 0;
1206         }
1207
1208         /**
1209          * Does that page contain wikitext, or it is JS, CSS or whatever?
1210          *
1211          * @return bool
1212          */
1213         public function isWikitextPage() {
1214                 return $this->hasContentModel( CONTENT_MODEL_WIKITEXT );
1215         }
1216
1217         /**
1218          * Could this page contain custom CSS or JavaScript for the global UI.
1219          * This is generally true for pages in the MediaWiki namespace having CONTENT_MODEL_CSS
1220          * or CONTENT_MODEL_JAVASCRIPT.
1221          *
1222          * This method does *not* return true for per-user JS/CSS. Use isCssJsSubpage()
1223          * for that!
1224          *
1225          * Note that this method should not return true for pages that contain and
1226          * show "inactive" CSS or JS.
1227          *
1228          * @return bool
1229          * @todo FIXME: Rename to isSiteConfigPage() and remove deprecated hook
1230          */
1231         public function isCssOrJsPage() {
1232                 $isCssOrJsPage = NS_MEDIAWIKI == $this->mNamespace
1233                         && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1234                                 || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1235
1236                 return $isCssOrJsPage;
1237         }
1238
1239         /**
1240          * Is this a .css or .js subpage of a user page?
1241          * @return bool
1242          * @todo FIXME: Rename to isUserConfigPage()
1243          */
1244         public function isCssJsSubpage() {
1245                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1246                                 && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1247                                         || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) ) );
1248         }
1249
1250         /**
1251          * Trim down a .css or .js subpage title to get the corresponding skin name
1252          *
1253          * @return string Containing skin name from .css or .js subpage title
1254          */
1255         public function getSkinFromCssJsSubpage() {
1256                 $subpage = explode( '/', $this->mTextform );
1257                 $subpage = $subpage[count( $subpage ) - 1];
1258                 $lastdot = strrpos( $subpage, '.' );
1259                 if ( $lastdot === false ) {
1260                         return $subpage; # Never happens: only called for names ending in '.css' or '.js'
1261                 }
1262                 return substr( $subpage, 0, $lastdot );
1263         }
1264
1265         /**
1266          * Is this a .css subpage of a user page?
1267          *
1268          * @return bool
1269          */
1270         public function isCssSubpage() {
1271                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1272                         && $this->hasContentModel( CONTENT_MODEL_CSS ) );
1273         }
1274
1275         /**
1276          * Is this a .js subpage of a user page?
1277          *
1278          * @return bool
1279          */
1280         public function isJsSubpage() {
1281                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1282                         && $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1283         }
1284
1285         /**
1286          * Is this a talk page of some sort?
1287          *
1288          * @return bool
1289          */
1290         public function isTalkPage() {
1291                 return MWNamespace::isTalk( $this->getNamespace() );
1292         }
1293
1294         /**
1295          * Get a Title object associated with the talk page of this article
1296          *
1297          * @return Title The object for the talk page
1298          */
1299         public function getTalkPage() {
1300                 return Title::makeTitle( MWNamespace::getTalk( $this->getNamespace() ), $this->getDBkey() );
1301         }
1302
1303         /**
1304          * Get a title object associated with the subject page of this
1305          * talk page
1306          *
1307          * @return Title The object for the subject page
1308          */
1309         public function getSubjectPage() {
1310                 // Is this the same title?
1311                 $subjectNS = MWNamespace::getSubject( $this->getNamespace() );
1312                 if ( $this->getNamespace() == $subjectNS ) {
1313                         return $this;
1314                 }
1315                 return Title::makeTitle( $subjectNS, $this->getDBkey() );
1316         }
1317
1318         /**
1319          * Get the other title for this page, if this is a subject page
1320          * get the talk page, if it is a subject page get the talk page
1321          *
1322          * @since 1.25
1323          * @throws MWException
1324          * @return Title
1325          */
1326         public function getOtherPage() {
1327                 if ( $this->isSpecialPage() ) {
1328                         throw new MWException( 'Special pages cannot have other pages' );
1329                 }
1330                 if ( $this->isTalkPage() ) {
1331                         return $this->getSubjectPage();
1332                 } else {
1333                         return $this->getTalkPage();
1334                 }
1335         }
1336
1337         /**
1338          * Get the default namespace index, for when there is no namespace
1339          *
1340          * @return int Default namespace index
1341          */
1342         public function getDefaultNamespace() {
1343                 return $this->mDefaultNamespace;
1344         }
1345
1346         /**
1347          * Get the Title fragment (i.e.\ the bit after the #) in text form
1348          *
1349          * Use Title::hasFragment to check for a fragment
1350          *
1351          * @return string Title fragment
1352          */
1353         public function getFragment() {
1354                 return $this->mFragment;
1355         }
1356
1357         /**
1358          * Check if a Title fragment is set
1359          *
1360          * @return bool
1361          * @since 1.23
1362          */
1363         public function hasFragment() {
1364                 return $this->mFragment !== '';
1365         }
1366
1367         /**
1368          * Get the fragment in URL form, including the "#" character if there is one
1369          * @return string Fragment in URL form
1370          */
1371         public function getFragmentForURL() {
1372                 if ( !$this->hasFragment() ) {
1373                         return '';
1374                 } else {
1375                         return '#' . Title::escapeFragmentForURL( $this->getFragment() );
1376                 }
1377         }
1378
1379         /**
1380          * Set the fragment for this title. Removes the first character from the
1381          * specified fragment before setting, so it assumes you're passing it with
1382          * an initial "#".
1383          *
1384          * Deprecated for public use, use Title::makeTitle() with fragment parameter,
1385          * or Title::createFragmentTarget().
1386          * Still in active use privately.
1387          *
1388          * @private
1389          * @param string $fragment Text
1390          */
1391         public function setFragment( $fragment ) {
1392                 $this->mFragment = strtr( substr( $fragment, 1 ), '_', ' ' );
1393         }
1394
1395         /**
1396          * Creates a new Title for a different fragment of the same page.
1397          *
1398          * @since 1.27
1399          * @param string $fragment
1400          * @return Title
1401          */
1402         public function createFragmentTarget( $fragment ) {
1403                 return self::makeTitle(
1404                         $this->getNamespace(),
1405                         $this->getText(),
1406                         $fragment,
1407                         $this->getInterwiki()
1408                 );
1409         }
1410
1411         /**
1412          * Prefix some arbitrary text with the namespace or interwiki prefix
1413          * of this object
1414          *
1415          * @param string $name The text
1416          * @return string The prefixed text
1417          */
1418         private function prefix( $name ) {
1419                 $p = '';
1420                 if ( $this->isExternal() ) {
1421                         $p = $this->mInterwiki . ':';
1422                 }
1423
1424                 if ( 0 != $this->mNamespace ) {
1425                         $p .= $this->getNsText() . ':';
1426                 }
1427                 return $p . $name;
1428         }
1429
1430         /**
1431          * Get the prefixed database key form
1432          *
1433          * @return string The prefixed title, with underscores and
1434          *  any interwiki and namespace prefixes
1435          */
1436         public function getPrefixedDBkey() {
1437                 $s = $this->prefix( $this->mDbkeyform );
1438                 $s = strtr( $s, ' ', '_' );
1439                 return $s;
1440         }
1441
1442         /**
1443          * Get the prefixed title with spaces.
1444          * This is the form usually used for display
1445          *
1446          * @return string The prefixed title, with spaces
1447          */
1448         public function getPrefixedText() {
1449                 if ( $this->mPrefixedText === null ) {
1450                         $s = $this->prefix( $this->mTextform );
1451                         $s = strtr( $s, '_', ' ' );
1452                         $this->mPrefixedText = $s;
1453                 }
1454                 return $this->mPrefixedText;
1455         }
1456
1457         /**
1458          * Return a string representation of this title
1459          *
1460          * @return string Representation of this title
1461          */
1462         public function __toString() {
1463                 return $this->getPrefixedText();
1464         }
1465
1466         /**
1467          * Get the prefixed title with spaces, plus any fragment
1468          * (part beginning with '#')
1469          *
1470          * @return string The prefixed title, with spaces and the fragment, including '#'
1471          */
1472         public function getFullText() {
1473                 $text = $this->getPrefixedText();
1474                 if ( $this->hasFragment() ) {
1475                         $text .= '#' . $this->getFragment();
1476                 }
1477                 return $text;
1478         }
1479
1480         /**
1481          * Get the root page name text without a namespace, i.e. the leftmost part before any slashes
1482          *
1483          * @par Example:
1484          * @code
1485          * Title::newFromText('User:Foo/Bar/Baz')->getRootText();
1486          * # returns: 'Foo'
1487          * @endcode
1488          *
1489          * @return string Root name
1490          * @since 1.20
1491          */
1492         public function getRootText() {
1493                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1494                         return $this->getText();
1495                 }
1496
1497                 return strtok( $this->getText(), '/' );
1498         }
1499
1500         /**
1501          * Get the root page name title, i.e. the leftmost part before any slashes
1502          *
1503          * @par Example:
1504          * @code
1505          * Title::newFromText('User:Foo/Bar/Baz')->getRootTitle();
1506          * # returns: Title{User:Foo}
1507          * @endcode
1508          *
1509          * @return Title Root title
1510          * @since 1.20
1511          */
1512         public function getRootTitle() {
1513                 return Title::makeTitle( $this->getNamespace(), $this->getRootText() );
1514         }
1515
1516         /**
1517          * Get the base page name without a namespace, i.e. the part before the subpage name
1518          *
1519          * @par Example:
1520          * @code
1521          * Title::newFromText('User:Foo/Bar/Baz')->getBaseText();
1522          * # returns: 'Foo/Bar'
1523          * @endcode
1524          *
1525          * @return string Base name
1526          */
1527         public function getBaseText() {
1528                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1529                         return $this->getText();
1530                 }
1531
1532                 $parts = explode( '/', $this->getText() );
1533                 # Don't discard the real title if there's no subpage involved
1534                 if ( count( $parts ) > 1 ) {
1535                         unset( $parts[count( $parts ) - 1] );
1536                 }
1537                 return implode( '/', $parts );
1538         }
1539
1540         /**
1541          * Get the base page name title, i.e. the part before the subpage name
1542          *
1543          * @par Example:
1544          * @code
1545          * Title::newFromText('User:Foo/Bar/Baz')->getBaseTitle();
1546          * # returns: Title{User:Foo/Bar}
1547          * @endcode
1548          *
1549          * @return Title Base title
1550          * @since 1.20
1551          */
1552         public function getBaseTitle() {
1553                 return Title::makeTitle( $this->getNamespace(), $this->getBaseText() );
1554         }
1555
1556         /**
1557          * Get the lowest-level subpage name, i.e. the rightmost part after any slashes
1558          *
1559          * @par Example:
1560          * @code
1561          * Title::newFromText('User:Foo/Bar/Baz')->getSubpageText();
1562          * # returns: "Baz"
1563          * @endcode
1564          *
1565          * @return string Subpage name
1566          */
1567         public function getSubpageText() {
1568                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1569                         return $this->mTextform;
1570                 }
1571                 $parts = explode( '/', $this->mTextform );
1572                 return $parts[count( $parts ) - 1];
1573         }
1574
1575         /**
1576          * Get the title for a subpage of the current page
1577          *
1578          * @par Example:
1579          * @code
1580          * Title::newFromText('User:Foo/Bar/Baz')->getSubpage("Asdf");
1581          * # returns: Title{User:Foo/Bar/Baz/Asdf}
1582          * @endcode
1583          *
1584          * @param string $text The subpage name to add to the title
1585          * @return Title Subpage title
1586          * @since 1.20
1587          */
1588         public function getSubpage( $text ) {
1589                 return Title::makeTitleSafe( $this->getNamespace(), $this->getText() . '/' . $text );
1590         }
1591
1592         /**
1593          * Get a URL-encoded form of the subpage text
1594          *
1595          * @return string URL-encoded subpage name
1596          */
1597         public function getSubpageUrlForm() {
1598                 $text = $this->getSubpageText();
1599                 $text = wfUrlencode( strtr( $text, ' ', '_' ) );
1600                 return $text;
1601         }
1602
1603         /**
1604          * Get a URL-encoded title (not an actual URL) including interwiki
1605          *
1606          * @return string The URL-encoded form
1607          */
1608         public function getPrefixedURL() {
1609                 $s = $this->prefix( $this->mDbkeyform );
1610                 $s = wfUrlencode( strtr( $s, ' ', '_' ) );
1611                 return $s;
1612         }
1613
1614         /**
1615          * Helper to fix up the get{Canonical,Full,Link,Local,Internal}URL args
1616          * get{Canonical,Full,Link,Local,Internal}URL methods accepted an optional
1617          * second argument named variant. This was deprecated in favor
1618          * of passing an array of option with a "variant" key
1619          * Once $query2 is removed for good, this helper can be dropped
1620          * and the wfArrayToCgi moved to getLocalURL();
1621          *
1622          * @since 1.19 (r105919)
1623          * @param array|string $query
1624          * @param string|string[]|bool $query2
1625          * @return string
1626          */
1627         private static function fixUrlQueryArgs( $query, $query2 = false ) {
1628                 if ( $query2 !== false ) {
1629                         wfDeprecated( "Title::get{Canonical,Full,Link,Local,Internal}URL " .
1630                                 "method called with a second parameter is deprecated. Add your " .
1631                                 "parameter to an array passed as the first parameter.", "1.19" );
1632                 }
1633                 if ( is_array( $query ) ) {
1634                         $query = wfArrayToCgi( $query );
1635                 }
1636                 if ( $query2 ) {
1637                         if ( is_string( $query2 ) ) {
1638                                 // $query2 is a string, we will consider this to be
1639                                 // a deprecated $variant argument and add it to the query
1640                                 $query2 = wfArrayToCgi( [ 'variant' => $query2 ] );
1641                         } else {
1642                                 $query2 = wfArrayToCgi( $query2 );
1643                         }
1644                         // If we have $query content add a & to it first
1645                         if ( $query ) {
1646                                 $query .= '&';
1647                         }
1648                         // Now append the queries together
1649                         $query .= $query2;
1650                 }
1651                 return $query;
1652         }
1653
1654         /**
1655          * Get a real URL referring to this title, with interwiki link and
1656          * fragment
1657          *
1658          * @see self::getLocalURL for the arguments.
1659          * @see wfExpandUrl
1660          * @param string|string[] $query
1661          * @param string|string[]|bool $query2
1662          * @param string $proto Protocol type to use in URL
1663          * @return string The URL
1664          */
1665         public function getFullURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1666                 $query = self::fixUrlQueryArgs( $query, $query2 );
1667
1668                 # Hand off all the decisions on urls to getLocalURL
1669                 $url = $this->getLocalURL( $query );
1670
1671                 # Expand the url to make it a full url. Note that getLocalURL has the
1672                 # potential to output full urls for a variety of reasons, so we use
1673                 # wfExpandUrl instead of simply prepending $wgServer
1674                 $url = wfExpandUrl( $url, $proto );
1675
1676                 # Finally, add the fragment.
1677                 $url .= $this->getFragmentForURL();
1678                 // Avoid PHP 7.1 warning from passing $this by reference
1679                 $titleRef = $this;
1680                 Hooks::run( 'GetFullURL', [ &$titleRef, &$url, $query ] );
1681                 return $url;
1682         }
1683
1684         /**
1685          * Get a URL with no fragment or server name (relative URL) from a Title object.
1686          * If this page is generated with action=render, however,
1687          * $wgServer is prepended to make an absolute URL.
1688          *
1689          * @see self::getFullURL to always get an absolute URL.
1690          * @see self::getLinkURL to always get a URL that's the simplest URL that will be
1691          *  valid to link, locally, to the current Title.
1692          * @see self::newFromText to produce a Title object.
1693          *
1694          * @param string|string[] $query An optional query string,
1695          *   not used for interwiki links. Can be specified as an associative array as well,
1696          *   e.g., array( 'action' => 'edit' ) (keys and values will be URL-escaped).
1697          *   Some query patterns will trigger various shorturl path replacements.
1698          * @param string|string[]|bool $query2 An optional secondary query array. This one MUST
1699          *   be an array. If a string is passed it will be interpreted as a deprecated
1700          *   variant argument and urlencoded into a variant= argument.
1701          *   This second query argument will be added to the $query
1702          *   The second parameter is deprecated since 1.19. Pass it as a key,value
1703          *   pair in the first parameter array instead.
1704          *
1705          * @return string String of the URL.
1706          */
1707         public function getLocalURL( $query = '', $query2 = false ) {
1708                 global $wgArticlePath, $wgScript, $wgServer, $wgRequest;
1709
1710                 $query = self::fixUrlQueryArgs( $query, $query2 );
1711
1712                 $interwiki = self::getInterwikiLookup()->fetch( $this->mInterwiki );
1713                 if ( $interwiki ) {
1714                         $namespace = $this->getNsText();
1715                         if ( $namespace != '' ) {
1716                                 # Can this actually happen? Interwikis shouldn't be parsed.
1717                                 # Yes! It can in interwiki transclusion. But... it probably shouldn't.
1718                                 $namespace .= ':';
1719                         }
1720                         $url = $interwiki->getURL( $namespace . $this->getDBkey() );
1721                         $url = wfAppendQuery( $url, $query );
1722                 } else {
1723                         $dbkey = wfUrlencode( $this->getPrefixedDBkey() );
1724                         if ( $query == '' ) {
1725                                 $url = str_replace( '$1', $dbkey, $wgArticlePath );
1726                                 // Avoid PHP 7.1 warning from passing $this by reference
1727                                 $titleRef = $this;
1728                                 Hooks::run( 'GetLocalURL::Article', [ &$titleRef, &$url ] );
1729                         } else {
1730                                 global $wgVariantArticlePath, $wgActionPaths, $wgContLang;
1731                                 $url = false;
1732                                 $matches = [];
1733
1734                                 if ( !empty( $wgActionPaths )
1735                                         && preg_match( '/^(.*&|)action=([^&]*)(&(.*)|)$/', $query, $matches )
1736                                 ) {
1737                                         $action = urldecode( $matches[2] );
1738                                         if ( isset( $wgActionPaths[$action] ) ) {
1739                                                 $query = $matches[1];
1740                                                 if ( isset( $matches[4] ) ) {
1741                                                         $query .= $matches[4];
1742                                                 }
1743                                                 $url = str_replace( '$1', $dbkey, $wgActionPaths[$action] );
1744                                                 if ( $query != '' ) {
1745                                                         $url = wfAppendQuery( $url, $query );
1746                                                 }
1747                                         }
1748                                 }
1749
1750                                 if ( $url === false
1751                                         && $wgVariantArticlePath
1752                                         && preg_match( '/^variant=([^&]*)$/', $query, $matches )
1753                                         && $this->getPageLanguage()->equals( $wgContLang )
1754                                         && $this->getPageLanguage()->hasVariants()
1755                                 ) {
1756                                         $variant = urldecode( $matches[1] );
1757                                         if ( $this->getPageLanguage()->hasVariant( $variant ) ) {
1758                                                 // Only do the variant replacement if the given variant is a valid
1759                                                 // variant for the page's language.
1760                                                 $url = str_replace( '$2', urlencode( $variant ), $wgVariantArticlePath );
1761                                                 $url = str_replace( '$1', $dbkey, $url );
1762                                         }
1763                                 }
1764
1765                                 if ( $url === false ) {
1766                                         if ( $query == '-' ) {
1767                                                 $query = '';
1768                                         }
1769                                         $url = "{$wgScript}?title={$dbkey}&{$query}";
1770                                 }
1771                         }
1772                         // Avoid PHP 7.1 warning from passing $this by reference
1773                         $titleRef = $this;
1774                         Hooks::run( 'GetLocalURL::Internal', [ &$titleRef, &$url, $query ] );
1775
1776                         // @todo FIXME: This causes breakage in various places when we
1777                         // actually expected a local URL and end up with dupe prefixes.
1778                         if ( $wgRequest->getVal( 'action' ) == 'render' ) {
1779                                 $url = $wgServer . $url;
1780                         }
1781                 }
1782                 // Avoid PHP 7.1 warning from passing $this by reference
1783                 $titleRef = $this;
1784                 Hooks::run( 'GetLocalURL', [ &$titleRef, &$url, $query ] );
1785                 return $url;
1786         }
1787
1788         /**
1789          * Get a URL that's the simplest URL that will be valid to link, locally,
1790          * to the current Title.  It includes the fragment, but does not include
1791          * the server unless action=render is used (or the link is external).  If
1792          * there's a fragment but the prefixed text is empty, we just return a link
1793          * to the fragment.
1794          *
1795          * The result obviously should not be URL-escaped, but does need to be
1796          * HTML-escaped if it's being output in HTML.
1797          *
1798          * @param string|string[] $query
1799          * @param bool $query2
1800          * @param string|int|bool $proto A PROTO_* constant on how the URL should be expanded,
1801          *                               or false (default) for no expansion
1802          * @see self::getLocalURL for the arguments.
1803          * @return string The URL
1804          */
1805         public function getLinkURL( $query = '', $query2 = false, $proto = false ) {
1806                 if ( $this->isExternal() || $proto !== false ) {
1807                         $ret = $this->getFullURL( $query, $query2, $proto );
1808                 } elseif ( $this->getPrefixedText() === '' && $this->hasFragment() ) {
1809                         $ret = $this->getFragmentForURL();
1810                 } else {
1811                         $ret = $this->getLocalURL( $query, $query2 ) . $this->getFragmentForURL();
1812                 }
1813                 return $ret;
1814         }
1815
1816         /**
1817          * Get the URL form for an internal link.
1818          * - Used in various CDN-related code, in case we have a different
1819          * internal hostname for the server from the exposed one.
1820          *
1821          * This uses $wgInternalServer to qualify the path, or $wgServer
1822          * if $wgInternalServer is not set. If the server variable used is
1823          * protocol-relative, the URL will be expanded to http://
1824          *
1825          * @see self::getLocalURL for the arguments.
1826          * @return string The URL
1827          */
1828         public function getInternalURL( $query = '', $query2 = false ) {
1829                 global $wgInternalServer, $wgServer;
1830                 $query = self::fixUrlQueryArgs( $query, $query2 );
1831                 $server = $wgInternalServer !== false ? $wgInternalServer : $wgServer;
1832                 $url = wfExpandUrl( $server . $this->getLocalURL( $query ), PROTO_HTTP );
1833                 // Avoid PHP 7.1 warning from passing $this by reference
1834                 $titleRef = $this;
1835                 Hooks::run( 'GetInternalURL', [ &$titleRef, &$url, $query ] );
1836                 return $url;
1837         }
1838
1839         /**
1840          * Get the URL for a canonical link, for use in things like IRC and
1841          * e-mail notifications. Uses $wgCanonicalServer and the
1842          * GetCanonicalURL hook.
1843          *
1844          * NOTE: Unlike getInternalURL(), the canonical URL includes the fragment
1845          *
1846          * @see self::getLocalURL for the arguments.
1847          * @return string The URL
1848          * @since 1.18
1849          */
1850         public function getCanonicalURL( $query = '', $query2 = false ) {
1851                 $query = self::fixUrlQueryArgs( $query, $query2 );
1852                 $url = wfExpandUrl( $this->getLocalURL( $query ) . $this->getFragmentForURL(), PROTO_CANONICAL );
1853                 // Avoid PHP 7.1 warning from passing $this by reference
1854                 $titleRef = $this;
1855                 Hooks::run( 'GetCanonicalURL', [ &$titleRef, &$url, $query ] );
1856                 return $url;
1857         }
1858
1859         /**
1860          * Get the edit URL for this Title
1861          *
1862          * @return string The URL, or a null string if this is an interwiki link
1863          */
1864         public function getEditURL() {
1865                 if ( $this->isExternal() ) {
1866                         return '';
1867                 }
1868                 $s = $this->getLocalURL( 'action=edit' );
1869
1870                 return $s;
1871         }
1872
1873         /**
1874          * Can $user perform $action on this page?
1875          * This skips potentially expensive cascading permission checks
1876          * as well as avoids expensive error formatting
1877          *
1878          * Suitable for use for nonessential UI controls in common cases, but
1879          * _not_ for functional access control.
1880          *
1881          * May provide false positives, but should never provide a false negative.
1882          *
1883          * @param string $action Action that permission needs to be checked for
1884          * @param User $user User to check (since 1.19); $wgUser will be used if not provided.
1885          * @return bool
1886          */
1887         public function quickUserCan( $action, $user = null ) {
1888                 return $this->userCan( $action, $user, false );
1889         }
1890
1891         /**
1892          * Can $user perform $action on this page?
1893          *
1894          * @param string $action Action that permission needs to be checked for
1895          * @param User $user User to check (since 1.19); $wgUser will be used if not
1896          *   provided.
1897          * @param string $rigor Same format as Title::getUserPermissionsErrors()
1898          * @return bool
1899          */
1900         public function userCan( $action, $user = null, $rigor = 'secure' ) {
1901                 if ( !$user instanceof User ) {
1902                         global $wgUser;
1903                         $user = $wgUser;
1904                 }
1905
1906                 return !count( $this->getUserPermissionsErrorsInternal( $action, $user, $rigor, true ) );
1907         }
1908
1909         /**
1910          * Can $user perform $action on this page?
1911          *
1912          * @todo FIXME: This *does not* check throttles (User::pingLimiter()).
1913          *
1914          * @param string $action Action that permission needs to be checked for
1915          * @param User $user User to check
1916          * @param string $rigor One of (quick,full,secure)
1917          *   - quick  : does cheap permission checks from replica DBs (usable for GUI creation)
1918          *   - full   : does cheap and expensive checks possibly from a replica DB
1919          *   - secure : does cheap and expensive checks, using the master as needed
1920          * @param array $ignoreErrors Array of Strings Set this to a list of message keys
1921          *   whose corresponding errors may be ignored.
1922          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
1923          */
1924         public function getUserPermissionsErrors(
1925                 $action, $user, $rigor = 'secure', $ignoreErrors = []
1926         ) {
1927                 $errors = $this->getUserPermissionsErrorsInternal( $action, $user, $rigor );
1928
1929                 // Remove the errors being ignored.
1930                 foreach ( $errors as $index => $error ) {
1931                         $errKey = is_array( $error ) ? $error[0] : $error;
1932
1933                         if ( in_array( $errKey, $ignoreErrors ) ) {
1934                                 unset( $errors[$index] );
1935                         }
1936                         if ( $errKey instanceof MessageSpecifier && in_array( $errKey->getKey(), $ignoreErrors ) ) {
1937                                 unset( $errors[$index] );
1938                         }
1939                 }
1940
1941                 return $errors;
1942         }
1943
1944         /**
1945          * Permissions checks that fail most often, and which are easiest to test.
1946          *
1947          * @param string $action The action to check
1948          * @param User $user User to check
1949          * @param array $errors List of current errors
1950          * @param string $rigor Same format as Title::getUserPermissionsErrors()
1951          * @param bool $short Short circuit on first error
1952          *
1953          * @return array List of errors
1954          */
1955         private function checkQuickPermissions( $action, $user, $errors, $rigor, $short ) {
1956                 if ( !Hooks::run( 'TitleQuickPermissions',
1957                         [ $this, $user, $action, &$errors, ( $rigor !== 'quick' ), $short ] )
1958                 ) {
1959                         return $errors;
1960                 }
1961
1962                 if ( $action == 'create' ) {
1963                         if (
1964                                 ( $this->isTalkPage() && !$user->isAllowed( 'createtalk' ) ) ||
1965                                 ( !$this->isTalkPage() && !$user->isAllowed( 'createpage' ) )
1966                         ) {
1967                                 $errors[] = $user->isAnon() ? [ 'nocreatetext' ] : [ 'nocreate-loggedin' ];
1968                         }
1969                 } elseif ( $action == 'move' ) {
1970                         if ( !$user->isAllowed( 'move-rootuserpages' )
1971                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
1972                                 // Show user page-specific message only if the user can move other pages
1973                                 $errors[] = [ 'cant-move-user-page' ];
1974                         }
1975
1976                         // Check if user is allowed to move files if it's a file
1977                         if ( $this->mNamespace == NS_FILE && !$user->isAllowed( 'movefile' ) ) {
1978                                 $errors[] = [ 'movenotallowedfile' ];
1979                         }
1980
1981                         // Check if user is allowed to move category pages if it's a category page
1982                         if ( $this->mNamespace == NS_CATEGORY && !$user->isAllowed( 'move-categorypages' ) ) {
1983                                 $errors[] = [ 'cant-move-category-page' ];
1984                         }
1985
1986                         if ( !$user->isAllowed( 'move' ) ) {
1987                                 // User can't move anything
1988                                 $userCanMove = User::groupHasPermission( 'user', 'move' );
1989                                 $autoconfirmedCanMove = User::groupHasPermission( 'autoconfirmed', 'move' );
1990                                 if ( $user->isAnon() && ( $userCanMove || $autoconfirmedCanMove ) ) {
1991                                         // custom message if logged-in users without any special rights can move
1992                                         $errors[] = [ 'movenologintext' ];
1993                                 } else {
1994                                         $errors[] = [ 'movenotallowed' ];
1995                                 }
1996                         }
1997                 } elseif ( $action == 'move-target' ) {
1998                         if ( !$user->isAllowed( 'move' ) ) {
1999                                 // User can't move anything
2000                                 $errors[] = [ 'movenotallowed' ];
2001                         } elseif ( !$user->isAllowed( 'move-rootuserpages' )
2002                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
2003                                 // Show user page-specific message only if the user can move other pages
2004                                 $errors[] = [ 'cant-move-to-user-page' ];
2005                         } elseif ( !$user->isAllowed( 'move-categorypages' )
2006                                         && $this->mNamespace == NS_CATEGORY ) {
2007                                 // Show category page-specific message only if the user can move other pages
2008                                 $errors[] = [ 'cant-move-to-category-page' ];
2009                         }
2010                 } elseif ( !$user->isAllowed( $action ) ) {
2011                         $errors[] = $this->missingPermissionError( $action, $short );
2012                 }
2013
2014                 return $errors;
2015         }
2016
2017         /**
2018          * Add the resulting error code to the errors array
2019          *
2020          * @param array $errors List of current errors
2021          * @param array $result Result of errors
2022          *
2023          * @return array List of errors
2024          */
2025         private function resultToError( $errors, $result ) {
2026                 if ( is_array( $result ) && count( $result ) && !is_array( $result[0] ) ) {
2027                         // A single array representing an error
2028                         $errors[] = $result;
2029                 } elseif ( is_array( $result ) && is_array( $result[0] ) ) {
2030                         // A nested array representing multiple errors
2031                         $errors = array_merge( $errors, $result );
2032                 } elseif ( $result !== '' && is_string( $result ) ) {
2033                         // A string representing a message-id
2034                         $errors[] = [ $result ];
2035                 } elseif ( $result instanceof MessageSpecifier ) {
2036                         // A message specifier representing an error
2037                         $errors[] = [ $result ];
2038                 } elseif ( $result === false ) {
2039                         // a generic "We don't want them to do that"
2040                         $errors[] = [ 'badaccess-group0' ];
2041                 }
2042                 return $errors;
2043         }
2044
2045         /**
2046          * Check various permission hooks
2047          *
2048          * @param string $action The action to check
2049          * @param User $user User to check
2050          * @param array $errors List of current errors
2051          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2052          * @param bool $short Short circuit on first error
2053          *
2054          * @return array List of errors
2055          */
2056         private function checkPermissionHooks( $action, $user, $errors, $rigor, $short ) {
2057                 // Use getUserPermissionsErrors instead
2058                 $result = '';
2059                 // Avoid PHP 7.1 warning from passing $this by reference
2060                 $titleRef = $this;
2061                 if ( !Hooks::run( 'userCan', [ &$titleRef, &$user, $action, &$result ] ) ) {
2062                         return $result ? [] : [ [ 'badaccess-group0' ] ];
2063                 }
2064                 // Check getUserPermissionsErrors hook
2065                 // Avoid PHP 7.1 warning from passing $this by reference
2066                 $titleRef = $this;
2067                 if ( !Hooks::run( 'getUserPermissionsErrors', [ &$titleRef, &$user, $action, &$result ] ) ) {
2068                         $errors = $this->resultToError( $errors, $result );
2069                 }
2070                 // Check getUserPermissionsErrorsExpensive hook
2071                 if (
2072                         $rigor !== 'quick'
2073                         && !( $short && count( $errors ) > 0 )
2074                         && !Hooks::run( 'getUserPermissionsErrorsExpensive', [ &$titleRef, &$user, $action, &$result ] )
2075                 ) {
2076                         $errors = $this->resultToError( $errors, $result );
2077                 }
2078
2079                 return $errors;
2080         }
2081
2082         /**
2083          * Check permissions on special pages & namespaces
2084          *
2085          * @param string $action The action to check
2086          * @param User $user User to check
2087          * @param array $errors List of current errors
2088          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2089          * @param bool $short Short circuit on first error
2090          *
2091          * @return array List of errors
2092          */
2093         private function checkSpecialsAndNSPermissions( $action, $user, $errors, $rigor, $short ) {
2094                 # Only 'createaccount' can be performed on special pages,
2095                 # which don't actually exist in the DB.
2096                 if ( NS_SPECIAL == $this->mNamespace && $action !== 'createaccount' ) {
2097                         $errors[] = [ 'ns-specialprotected' ];
2098                 }
2099
2100                 # Check $wgNamespaceProtection for restricted namespaces
2101                 if ( $this->isNamespaceProtected( $user ) ) {
2102                         $ns = $this->mNamespace == NS_MAIN ?
2103                                 wfMessage( 'nstab-main' )->text() : $this->getNsText();
2104                         $errors[] = $this->mNamespace == NS_MEDIAWIKI ?
2105                                 [ 'protectedinterface', $action ] : [ 'namespaceprotected', $ns, $action ];
2106                 }
2107
2108                 return $errors;
2109         }
2110
2111         /**
2112          * Check CSS/JS sub-page permissions
2113          *
2114          * @param string $action The action to check
2115          * @param User $user User to check
2116          * @param array $errors List of current errors
2117          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2118          * @param bool $short Short circuit on first error
2119          *
2120          * @return array List of errors
2121          */
2122         private function checkCSSandJSPermissions( $action, $user, $errors, $rigor, $short ) {
2123                 # Protect css/js subpages of user pages
2124                 # XXX: this might be better using restrictions
2125                 # XXX: right 'editusercssjs' is deprecated, for backward compatibility only
2126                 if ( $action != 'patrol' && !$user->isAllowed( 'editusercssjs' ) ) {
2127                         if ( preg_match( '/^' . preg_quote( $user->getName(), '/' ) . '\//', $this->mTextform ) ) {
2128                                 if ( $this->isCssSubpage() && !$user->isAllowedAny( 'editmyusercss', 'editusercss' ) ) {
2129                                         $errors[] = [ 'mycustomcssprotected', $action ];
2130                                 } elseif ( $this->isJsSubpage() && !$user->isAllowedAny( 'editmyuserjs', 'edituserjs' ) ) {
2131                                         $errors[] = [ 'mycustomjsprotected', $action ];
2132                                 }
2133                         } else {
2134                                 if ( $this->isCssSubpage() && !$user->isAllowed( 'editusercss' ) ) {
2135                                         $errors[] = [ 'customcssprotected', $action ];
2136                                 } elseif ( $this->isJsSubpage() && !$user->isAllowed( 'edituserjs' ) ) {
2137                                         $errors[] = [ 'customjsprotected', $action ];
2138                                 }
2139                         }
2140                 }
2141
2142                 return $errors;
2143         }
2144
2145         /**
2146          * Check against page_restrictions table requirements on this
2147          * page. The user must possess all required rights for this
2148          * action.
2149          *
2150          * @param string $action The action to check
2151          * @param User $user User to check
2152          * @param array $errors List of current errors
2153          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2154          * @param bool $short Short circuit on first error
2155          *
2156          * @return array List of errors
2157          */
2158         private function checkPageRestrictions( $action, $user, $errors, $rigor, $short ) {
2159                 foreach ( $this->getRestrictions( $action ) as $right ) {
2160                         // Backwards compatibility, rewrite sysop -> editprotected
2161                         if ( $right == 'sysop' ) {
2162                                 $right = 'editprotected';
2163                         }
2164                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2165                         if ( $right == 'autoconfirmed' ) {
2166                                 $right = 'editsemiprotected';
2167                         }
2168                         if ( $right == '' ) {
2169                                 continue;
2170                         }
2171                         if ( !$user->isAllowed( $right ) ) {
2172                                 $errors[] = [ 'protectedpagetext', $right, $action ];
2173                         } elseif ( $this->mCascadeRestriction && !$user->isAllowed( 'protect' ) ) {
2174                                 $errors[] = [ 'protectedpagetext', 'protect', $action ];
2175                         }
2176                 }
2177
2178                 return $errors;
2179         }
2180
2181         /**
2182          * Check restrictions on cascading pages.
2183          *
2184          * @param string $action The action to check
2185          * @param User $user User to check
2186          * @param array $errors List of current errors
2187          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2188          * @param bool $short Short circuit on first error
2189          *
2190          * @return array List of errors
2191          */
2192         private function checkCascadingSourcesRestrictions( $action, $user, $errors, $rigor, $short ) {
2193                 if ( $rigor !== 'quick' && !$this->isCssJsSubpage() ) {
2194                         # We /could/ use the protection level on the source page, but it's
2195                         # fairly ugly as we have to establish a precedence hierarchy for pages
2196                         # included by multiple cascade-protected pages. So just restrict
2197                         # it to people with 'protect' permission, as they could remove the
2198                         # protection anyway.
2199                         list( $cascadingSources, $restrictions ) = $this->getCascadeProtectionSources();
2200                         # Cascading protection depends on more than this page...
2201                         # Several cascading protected pages may include this page...
2202                         # Check each cascading level
2203                         # This is only for protection restrictions, not for all actions
2204                         if ( isset( $restrictions[$action] ) ) {
2205                                 foreach ( $restrictions[$action] as $right ) {
2206                                         // Backwards compatibility, rewrite sysop -> editprotected
2207                                         if ( $right == 'sysop' ) {
2208                                                 $right = 'editprotected';
2209                                         }
2210                                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2211                                         if ( $right == 'autoconfirmed' ) {
2212                                                 $right = 'editsemiprotected';
2213                                         }
2214                                         if ( $right != '' && !$user->isAllowedAll( 'protect', $right ) ) {
2215                                                 $pages = '';
2216                                                 foreach ( $cascadingSources as $page ) {
2217                                                         $pages .= '* [[:' . $page->getPrefixedText() . "]]\n";
2218                                                 }
2219                                                 $errors[] = [ 'cascadeprotected', count( $cascadingSources ), $pages, $action ];
2220                                         }
2221                                 }
2222                         }
2223                 }
2224
2225                 return $errors;
2226         }
2227
2228         /**
2229          * Check action permissions not already checked in checkQuickPermissions
2230          *
2231          * @param string $action The action to check
2232          * @param User $user User to check
2233          * @param array $errors List of current errors
2234          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2235          * @param bool $short Short circuit on first error
2236          *
2237          * @return array List of errors
2238          */
2239         private function checkActionPermissions( $action, $user, $errors, $rigor, $short ) {
2240                 global $wgDeleteRevisionsLimit, $wgLang;
2241
2242                 if ( $action == 'protect' ) {
2243                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit', $user, $rigor, true ) ) ) {
2244                                 // If they can't edit, they shouldn't protect.
2245                                 $errors[] = [ 'protect-cantedit' ];
2246                         }
2247                 } elseif ( $action == 'create' ) {
2248                         $title_protection = $this->getTitleProtection();
2249                         if ( $title_protection ) {
2250                                 if ( $title_protection['permission'] == ''
2251                                         || !$user->isAllowed( $title_protection['permission'] )
2252                                 ) {
2253                                         $errors[] = [
2254                                                 'titleprotected',
2255                                                 User::whoIs( $title_protection['user'] ),
2256                                                 $title_protection['reason']
2257                                         ];
2258                                 }
2259                         }
2260                 } elseif ( $action == 'move' ) {
2261                         // Check for immobile pages
2262                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2263                                 // Specific message for this case
2264                                 $errors[] = [ 'immobile-source-namespace', $this->getNsText() ];
2265                         } elseif ( !$this->isMovable() ) {
2266                                 // Less specific message for rarer cases
2267                                 $errors[] = [ 'immobile-source-page' ];
2268                         }
2269                 } elseif ( $action == 'move-target' ) {
2270                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2271                                 $errors[] = [ 'immobile-target-namespace', $this->getNsText() ];
2272                         } elseif ( !$this->isMovable() ) {
2273                                 $errors[] = [ 'immobile-target-page' ];
2274                         }
2275                 } elseif ( $action == 'delete' ) {
2276                         $tempErrors = $this->checkPageRestrictions( 'edit', $user, [], $rigor, true );
2277                         if ( !$tempErrors ) {
2278                                 $tempErrors = $this->checkCascadingSourcesRestrictions( 'edit',
2279                                         $user, $tempErrors, $rigor, true );
2280                         }
2281                         if ( $tempErrors ) {
2282                                 // If protection keeps them from editing, they shouldn't be able to delete.
2283                                 $errors[] = [ 'deleteprotected' ];
2284                         }
2285                         if ( $rigor !== 'quick' && $wgDeleteRevisionsLimit
2286                                 && !$this->userCan( 'bigdelete', $user ) && $this->isBigDeletion()
2287                         ) {
2288                                 $errors[] = [ 'delete-toobig', $wgLang->formatNum( $wgDeleteRevisionsLimit ) ];
2289                         }
2290                 }
2291                 return $errors;
2292         }
2293
2294         /**
2295          * Check that the user isn't blocked from editing.
2296          *
2297          * @param string $action The action to check
2298          * @param User $user User to check
2299          * @param array $errors List of current errors
2300          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2301          * @param bool $short Short circuit on first error
2302          *
2303          * @return array List of errors
2304          */
2305         private function checkUserBlock( $action, $user, $errors, $rigor, $short ) {
2306                 global $wgEmailConfirmToEdit, $wgBlockDisablesLogin;
2307                 // Account creation blocks handled at userlogin.
2308                 // Unblocking handled in SpecialUnblock
2309                 if ( $rigor === 'quick' || in_array( $action, [ 'createaccount', 'unblock' ] ) ) {
2310                         return $errors;
2311                 }
2312
2313                 // Optimize for a very common case
2314                 if ( $action === 'read' && !$wgBlockDisablesLogin ) {
2315                         return $errors;
2316                 }
2317
2318                 if ( $wgEmailConfirmToEdit && !$user->isEmailConfirmed() ) {
2319                         $errors[] = [ 'confirmedittext' ];
2320                 }
2321
2322                 $useSlave = ( $rigor !== 'secure' );
2323                 if ( ( $action == 'edit' || $action == 'create' )
2324                         && !$user->isBlockedFrom( $this, $useSlave )
2325                 ) {
2326                         // Don't block the user from editing their own talk page unless they've been
2327                         // explicitly blocked from that too.
2328                 } elseif ( $user->isBlocked() && $user->getBlock()->prevents( $action ) !== false ) {
2329                         // @todo FIXME: Pass the relevant context into this function.
2330                         $errors[] = $user->getBlock()->getPermissionsError( RequestContext::getMain() );
2331                 }
2332
2333                 return $errors;
2334         }
2335
2336         /**
2337          * Check that the user is allowed to read this page.
2338          *
2339          * @param string $action The action to check
2340          * @param User $user User to check
2341          * @param array $errors List of current errors
2342          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2343          * @param bool $short Short circuit on first error
2344          *
2345          * @return array List of errors
2346          */
2347         private function checkReadPermissions( $action, $user, $errors, $rigor, $short ) {
2348                 global $wgWhitelistRead, $wgWhitelistReadRegexp;
2349
2350                 $whitelisted = false;
2351                 if ( User::isEveryoneAllowed( 'read' ) ) {
2352                         # Shortcut for public wikis, allows skipping quite a bit of code
2353                         $whitelisted = true;
2354                 } elseif ( $user->isAllowed( 'read' ) ) {
2355                         # If the user is allowed to read pages, he is allowed to read all pages
2356                         $whitelisted = true;
2357                 } elseif ( $this->isSpecial( 'Userlogin' )
2358                         || $this->isSpecial( 'PasswordReset' )
2359                         || $this->isSpecial( 'Userlogout' )
2360                 ) {
2361                         # Always grant access to the login page.
2362                         # Even anons need to be able to log in.
2363                         $whitelisted = true;
2364                 } elseif ( is_array( $wgWhitelistRead ) && count( $wgWhitelistRead ) ) {
2365                         # Time to check the whitelist
2366                         # Only do these checks is there's something to check against
2367                         $name = $this->getPrefixedText();
2368                         $dbName = $this->getPrefixedDBkey();
2369
2370                         // Check for explicit whitelisting with and without underscores
2371                         if ( in_array( $name, $wgWhitelistRead, true ) || in_array( $dbName, $wgWhitelistRead, true ) ) {
2372                                 $whitelisted = true;
2373                         } elseif ( $this->getNamespace() == NS_MAIN ) {
2374                                 # Old settings might have the title prefixed with
2375                                 # a colon for main-namespace pages
2376                                 if ( in_array( ':' . $name, $wgWhitelistRead ) ) {
2377                                         $whitelisted = true;
2378                                 }
2379                         } elseif ( $this->isSpecialPage() ) {
2380                                 # If it's a special page, ditch the subpage bit and check again
2381                                 $name = $this->getDBkey();
2382                                 list( $name, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $name );
2383                                 if ( $name ) {
2384                                         $pure = SpecialPage::getTitleFor( $name )->getPrefixedText();
2385                                         if ( in_array( $pure, $wgWhitelistRead, true ) ) {
2386                                                 $whitelisted = true;
2387                                         }
2388                                 }
2389                         }
2390                 }
2391
2392                 if ( !$whitelisted && is_array( $wgWhitelistReadRegexp ) && !empty( $wgWhitelistReadRegexp ) ) {
2393                         $name = $this->getPrefixedText();
2394                         // Check for regex whitelisting
2395                         foreach ( $wgWhitelistReadRegexp as $listItem ) {
2396                                 if ( preg_match( $listItem, $name ) ) {
2397                                         $whitelisted = true;
2398                                         break;
2399                                 }
2400                         }
2401                 }
2402
2403                 if ( !$whitelisted ) {
2404                         # If the title is not whitelisted, give extensions a chance to do so...
2405                         Hooks::run( 'TitleReadWhitelist', [ $this, $user, &$whitelisted ] );
2406                         if ( !$whitelisted ) {
2407                                 $errors[] = $this->missingPermissionError( $action, $short );
2408                         }
2409                 }
2410
2411                 return $errors;
2412         }
2413
2414         /**
2415          * Get a description array when the user doesn't have the right to perform
2416          * $action (i.e. when User::isAllowed() returns false)
2417          *
2418          * @param string $action The action to check
2419          * @param bool $short Short circuit on first error
2420          * @return array Array containing an error message key and any parameters
2421          */
2422         private function missingPermissionError( $action, $short ) {
2423                 // We avoid expensive display logic for quickUserCan's and such
2424                 if ( $short ) {
2425                         return [ 'badaccess-group0' ];
2426                 }
2427
2428                 return User::newFatalPermissionDeniedStatus( $action )->getErrorsArray()[0];
2429         }
2430
2431         /**
2432          * Can $user perform $action on this page? This is an internal function,
2433          * with multiple levels of checks depending on performance needs; see $rigor below.
2434          * It does not check wfReadOnly().
2435          *
2436          * @param string $action Action that permission needs to be checked for
2437          * @param User $user User to check
2438          * @param string $rigor One of (quick,full,secure)
2439          *   - quick  : does cheap permission checks from replica DBs (usable for GUI creation)
2440          *   - full   : does cheap and expensive checks possibly from a replica DB
2441          *   - secure : does cheap and expensive checks, using the master as needed
2442          * @param bool $short Set this to true to stop after the first permission error.
2443          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
2444          */
2445         protected function getUserPermissionsErrorsInternal(
2446                 $action, $user, $rigor = 'secure', $short = false
2447         ) {
2448                 if ( $rigor === true ) {
2449                         $rigor = 'secure'; // b/c
2450                 } elseif ( $rigor === false ) {
2451                         $rigor = 'quick'; // b/c
2452                 } elseif ( !in_array( $rigor, [ 'quick', 'full', 'secure' ] ) ) {
2453                         throw new Exception( "Invalid rigor parameter '$rigor'." );
2454                 }
2455
2456                 # Read has special handling
2457                 if ( $action == 'read' ) {
2458                         $checks = [
2459                                 'checkPermissionHooks',
2460                                 'checkReadPermissions',
2461                                 'checkUserBlock', // for wgBlockDisablesLogin
2462                         ];
2463                 # Don't call checkSpecialsAndNSPermissions or checkCSSandJSPermissions
2464                 # here as it will lead to duplicate error messages. This is okay to do
2465                 # since anywhere that checks for create will also check for edit, and
2466                 # those checks are called for edit.
2467                 } elseif ( $action == 'create' ) {
2468                         $checks = [
2469                                 'checkQuickPermissions',
2470                                 'checkPermissionHooks',
2471                                 'checkPageRestrictions',
2472                                 'checkCascadingSourcesRestrictions',
2473                                 'checkActionPermissions',
2474                                 'checkUserBlock'
2475                         ];
2476                 } else {
2477                         $checks = [
2478                                 'checkQuickPermissions',
2479                                 'checkPermissionHooks',
2480                                 'checkSpecialsAndNSPermissions',
2481                                 'checkCSSandJSPermissions',
2482                                 'checkPageRestrictions',
2483                                 'checkCascadingSourcesRestrictions',
2484                                 'checkActionPermissions',
2485                                 'checkUserBlock'
2486                         ];
2487                 }
2488
2489                 $errors = [];
2490                 while ( count( $checks ) > 0 &&
2491                                 !( $short && count( $errors ) > 0 ) ) {
2492                         $method = array_shift( $checks );
2493                         $errors = $this->$method( $action, $user, $errors, $rigor, $short );
2494                 }
2495
2496                 return $errors;
2497         }
2498
2499         /**
2500          * Get a filtered list of all restriction types supported by this wiki.
2501          * @param bool $exists True to get all restriction types that apply to
2502          * titles that do exist, False for all restriction types that apply to
2503          * titles that do not exist
2504          * @return array
2505          */
2506         public static function getFilteredRestrictionTypes( $exists = true ) {
2507                 global $wgRestrictionTypes;
2508                 $types = $wgRestrictionTypes;
2509                 if ( $exists ) {
2510                         # Remove the create restriction for existing titles
2511                         $types = array_diff( $types, [ 'create' ] );
2512                 } else {
2513                         # Only the create and upload restrictions apply to non-existing titles
2514                         $types = array_intersect( $types, [ 'create', 'upload' ] );
2515                 }
2516                 return $types;
2517         }
2518
2519         /**
2520          * Returns restriction types for the current Title
2521          *
2522          * @return array Applicable restriction types
2523          */
2524         public function getRestrictionTypes() {
2525                 if ( $this->isSpecialPage() ) {
2526                         return [];
2527                 }
2528
2529                 $types = self::getFilteredRestrictionTypes( $this->exists() );
2530
2531                 if ( $this->getNamespace() != NS_FILE ) {
2532                         # Remove the upload restriction for non-file titles
2533                         $types = array_diff( $types, [ 'upload' ] );
2534                 }
2535
2536                 Hooks::run( 'TitleGetRestrictionTypes', [ $this, &$types ] );
2537
2538                 wfDebug( __METHOD__ . ': applicable restrictions to [[' .
2539                         $this->getPrefixedText() . ']] are {' . implode( ',', $types ) . "}\n" );
2540
2541                 return $types;
2542         }
2543
2544         /**
2545          * Is this title subject to title protection?
2546          * Title protection is the one applied against creation of such title.
2547          *
2548          * @return array|bool An associative array representing any existent title
2549          *   protection, or false if there's none.
2550          */
2551         public function getTitleProtection() {
2552                 $protection = $this->getTitleProtectionInternal();
2553                 if ( $protection ) {
2554                         if ( $protection['permission'] == 'sysop' ) {
2555                                 $protection['permission'] = 'editprotected'; // B/C
2556                         }
2557                         if ( $protection['permission'] == 'autoconfirmed' ) {
2558                                 $protection['permission'] = 'editsemiprotected'; // B/C
2559                         }
2560                 }
2561                 return $protection;
2562         }
2563
2564         /**
2565          * Fetch title protection settings
2566          *
2567          * To work correctly, $this->loadRestrictions() needs to have access to the
2568          * actual protections in the database without munging 'sysop' =>
2569          * 'editprotected' and 'autoconfirmed' => 'editsemiprotected'. Other
2570          * callers probably want $this->getTitleProtection() instead.
2571          *
2572          * @return array|bool
2573          */
2574         protected function getTitleProtectionInternal() {
2575                 // Can't protect pages in special namespaces
2576                 if ( $this->getNamespace() < 0 ) {
2577                         return false;
2578                 }
2579
2580                 // Can't protect pages that exist.
2581                 if ( $this->exists() ) {
2582                         return false;
2583                 }
2584
2585                 if ( $this->mTitleProtection === null ) {
2586                         $dbr = wfGetDB( DB_REPLICA );
2587                         $res = $dbr->select(
2588                                 'protected_titles',
2589                                 [
2590                                         'user' => 'pt_user',
2591                                         'reason' => 'pt_reason',
2592                                         'expiry' => 'pt_expiry',
2593                                         'permission' => 'pt_create_perm'
2594                                 ],
2595                                 [ 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ],
2596                                 __METHOD__
2597                         );
2598
2599                         // fetchRow returns false if there are no rows.
2600                         $row = $dbr->fetchRow( $res );
2601                         if ( $row ) {
2602                                 $row['expiry'] = $dbr->decodeExpiry( $row['expiry'] );
2603                         }
2604                         $this->mTitleProtection = $row;
2605                 }
2606                 return $this->mTitleProtection;
2607         }
2608
2609         /**
2610          * Remove any title protection due to page existing
2611          */
2612         public function deleteTitleProtection() {
2613                 $dbw = wfGetDB( DB_MASTER );
2614
2615                 $dbw->delete(
2616                         'protected_titles',
2617                         [ 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ],
2618                         __METHOD__
2619                 );
2620                 $this->mTitleProtection = false;
2621         }
2622
2623         /**
2624          * Is this page "semi-protected" - the *only* protection levels are listed
2625          * in $wgSemiprotectedRestrictionLevels?
2626          *
2627          * @param string $action Action to check (default: edit)
2628          * @return bool
2629          */
2630         public function isSemiProtected( $action = 'edit' ) {
2631                 global $wgSemiprotectedRestrictionLevels;
2632
2633                 $restrictions = $this->getRestrictions( $action );
2634                 $semi = $wgSemiprotectedRestrictionLevels;
2635                 if ( !$restrictions || !$semi ) {
2636                         // Not protected, or all protection is full protection
2637                         return false;
2638                 }
2639
2640                 // Remap autoconfirmed to editsemiprotected for BC
2641                 foreach ( array_keys( $semi, 'autoconfirmed' ) as $key ) {
2642                         $semi[$key] = 'editsemiprotected';
2643                 }
2644                 foreach ( array_keys( $restrictions, 'autoconfirmed' ) as $key ) {
2645                         $restrictions[$key] = 'editsemiprotected';
2646                 }
2647
2648                 return !array_diff( $restrictions, $semi );
2649         }
2650
2651         /**
2652          * Does the title correspond to a protected article?
2653          *
2654          * @param string $action The action the page is protected from,
2655          * by default checks all actions.
2656          * @return bool
2657          */
2658         public function isProtected( $action = '' ) {
2659                 global $wgRestrictionLevels;
2660
2661                 $restrictionTypes = $this->getRestrictionTypes();
2662
2663                 # Special pages have inherent protection
2664                 if ( $this->isSpecialPage() ) {
2665                         return true;
2666                 }
2667
2668                 # Check regular protection levels
2669                 foreach ( $restrictionTypes as $type ) {
2670                         if ( $action == $type || $action == '' ) {
2671                                 $r = $this->getRestrictions( $type );
2672                                 foreach ( $wgRestrictionLevels as $level ) {
2673                                         if ( in_array( $level, $r ) && $level != '' ) {
2674                                                 return true;
2675                                         }
2676                                 }
2677                         }
2678                 }
2679
2680                 return false;
2681         }
2682
2683         /**
2684          * Determines if $user is unable to edit this page because it has been protected
2685          * by $wgNamespaceProtection.
2686          *
2687          * @param User $user User object to check permissions
2688          * @return bool
2689          */
2690         public function isNamespaceProtected( User $user ) {
2691                 global $wgNamespaceProtection;
2692
2693                 if ( isset( $wgNamespaceProtection[$this->mNamespace] ) ) {
2694                         foreach ( (array)$wgNamespaceProtection[$this->mNamespace] as $right ) {
2695                                 if ( $right != '' && !$user->isAllowed( $right ) ) {
2696                                         return true;
2697                                 }
2698                         }
2699                 }
2700                 return false;
2701         }
2702
2703         /**
2704          * Cascading protection: Return true if cascading restrictions apply to this page, false if not.
2705          *
2706          * @return bool If the page is subject to cascading restrictions.
2707          */
2708         public function isCascadeProtected() {
2709                 list( $sources, /* $restrictions */ ) = $this->getCascadeProtectionSources( false );
2710                 return ( $sources > 0 );
2711         }
2712
2713         /**
2714          * Determines whether cascading protection sources have already been loaded from
2715          * the database.
2716          *
2717          * @param bool $getPages True to check if the pages are loaded, or false to check
2718          * if the status is loaded.
2719          * @return bool Whether or not the specified information has been loaded
2720          * @since 1.23
2721          */
2722         public function areCascadeProtectionSourcesLoaded( $getPages = true ) {
2723                 return $getPages ? $this->mCascadeSources !== null : $this->mHasCascadingRestrictions !== null;
2724         }
2725
2726         /**
2727          * Cascading protection: Get the source of any cascading restrictions on this page.
2728          *
2729          * @param bool $getPages Whether or not to retrieve the actual pages
2730          *        that the restrictions have come from and the actual restrictions
2731          *        themselves.
2732          * @return array Two elements: First is an array of Title objects of the
2733          *        pages from which cascading restrictions have come, false for
2734          *        none, or true if such restrictions exist but $getPages was not
2735          *        set. Second is an array like that returned by
2736          *        Title::getAllRestrictions(), or an empty array if $getPages is
2737          *        false.
2738          */
2739         public function getCascadeProtectionSources( $getPages = true ) {
2740                 $pagerestrictions = [];
2741
2742                 if ( $this->mCascadeSources !== null && $getPages ) {
2743                         return [ $this->mCascadeSources, $this->mCascadingRestrictions ];
2744                 } elseif ( $this->mHasCascadingRestrictions !== null && !$getPages ) {
2745                         return [ $this->mHasCascadingRestrictions, $pagerestrictions ];
2746                 }
2747
2748                 $dbr = wfGetDB( DB_REPLICA );
2749
2750                 if ( $this->getNamespace() == NS_FILE ) {
2751                         $tables = [ 'imagelinks', 'page_restrictions' ];
2752                         $where_clauses = [
2753                                 'il_to' => $this->getDBkey(),
2754                                 'il_from=pr_page',
2755                                 'pr_cascade' => 1
2756                         ];
2757                 } else {
2758                         $tables = [ 'templatelinks', 'page_restrictions' ];
2759                         $where_clauses = [
2760                                 'tl_namespace' => $this->getNamespace(),
2761                                 'tl_title' => $this->getDBkey(),
2762                                 'tl_from=pr_page',
2763                                 'pr_cascade' => 1
2764                         ];
2765                 }
2766
2767                 if ( $getPages ) {
2768                         $cols = [ 'pr_page', 'page_namespace', 'page_title',
2769                                 'pr_expiry', 'pr_type', 'pr_level' ];
2770                         $where_clauses[] = 'page_id=pr_page';
2771                         $tables[] = 'page';
2772                 } else {
2773                         $cols = [ 'pr_expiry' ];
2774                 }
2775
2776                 $res = $dbr->select( $tables, $cols, $where_clauses, __METHOD__ );
2777
2778                 $sources = $getPages ? [] : false;
2779                 $now = wfTimestampNow();
2780
2781                 foreach ( $res as $row ) {
2782                         $expiry = $dbr->decodeExpiry( $row->pr_expiry );
2783                         if ( $expiry > $now ) {
2784                                 if ( $getPages ) {
2785                                         $page_id = $row->pr_page;
2786                                         $page_ns = $row->page_namespace;
2787                                         $page_title = $row->page_title;
2788                                         $sources[$page_id] = Title::makeTitle( $page_ns, $page_title );
2789                                         # Add groups needed for each restriction type if its not already there
2790                                         # Make sure this restriction type still exists
2791
2792                                         if ( !isset( $pagerestrictions[$row->pr_type] ) ) {
2793                                                 $pagerestrictions[$row->pr_type] = [];
2794                                         }
2795
2796                                         if (
2797                                                 isset( $pagerestrictions[$row->pr_type] )
2798                                                 && !in_array( $row->pr_level, $pagerestrictions[$row->pr_type] )
2799                                         ) {
2800                                                 $pagerestrictions[$row->pr_type][] = $row->pr_level;
2801                                         }
2802                                 } else {
2803                                         $sources = true;
2804                                 }
2805                         }
2806                 }
2807
2808                 if ( $getPages ) {
2809                         $this->mCascadeSources = $sources;
2810                         $this->mCascadingRestrictions = $pagerestrictions;
2811                 } else {
2812                         $this->mHasCascadingRestrictions = $sources;
2813                 }
2814
2815                 return [ $sources, $pagerestrictions ];
2816         }
2817
2818         /**
2819          * Accessor for mRestrictionsLoaded
2820          *
2821          * @return bool Whether or not the page's restrictions have already been
2822          * loaded from the database
2823          * @since 1.23
2824          */
2825         public function areRestrictionsLoaded() {
2826                 return $this->mRestrictionsLoaded;
2827         }
2828
2829         /**
2830          * Accessor/initialisation for mRestrictions
2831          *
2832          * @param string $action Action that permission needs to be checked for
2833          * @return array Restriction levels needed to take the action. All levels are
2834          *     required. Note that restriction levels are normally user rights, but 'sysop'
2835          *     and 'autoconfirmed' are also allowed for backwards compatibility. These should
2836          *     be mapped to 'editprotected' and 'editsemiprotected' respectively.
2837          */
2838         public function getRestrictions( $action ) {
2839                 if ( !$this->mRestrictionsLoaded ) {
2840                         $this->loadRestrictions();
2841                 }
2842                 return isset( $this->mRestrictions[$action] )
2843                                 ? $this->mRestrictions[$action]
2844                                 : [];
2845         }
2846
2847         /**
2848          * Accessor/initialisation for mRestrictions
2849          *
2850          * @return array Keys are actions, values are arrays as returned by
2851          *     Title::getRestrictions()
2852          * @since 1.23
2853          */
2854         public function getAllRestrictions() {
2855                 if ( !$this->mRestrictionsLoaded ) {
2856                         $this->loadRestrictions();
2857                 }
2858                 return $this->mRestrictions;
2859         }
2860
2861         /**
2862          * Get the expiry time for the restriction against a given action
2863          *
2864          * @param string $action
2865          * @return string|bool 14-char timestamp, or 'infinity' if the page is protected forever
2866          *     or not protected at all, or false if the action is not recognised.
2867          */
2868         public function getRestrictionExpiry( $action ) {
2869                 if ( !$this->mRestrictionsLoaded ) {
2870                         $this->loadRestrictions();
2871                 }
2872                 return isset( $this->mRestrictionsExpiry[$action] ) ? $this->mRestrictionsExpiry[$action] : false;
2873         }
2874
2875         /**
2876          * Returns cascading restrictions for the current article
2877          *
2878          * @return bool
2879          */
2880         function areRestrictionsCascading() {
2881                 if ( !$this->mRestrictionsLoaded ) {
2882                         $this->loadRestrictions();
2883                 }
2884
2885                 return $this->mCascadeRestriction;
2886         }
2887
2888         /**
2889          * Compiles list of active page restrictions from both page table (pre 1.10)
2890          * and page_restrictions table for this existing page.
2891          * Public for usage by LiquidThreads.
2892          *
2893          * @param array $rows Array of db result objects
2894          * @param string $oldFashionedRestrictions Comma-separated list of page
2895          *   restrictions from page table (pre 1.10)
2896          */
2897         public function loadRestrictionsFromRows( $rows, $oldFashionedRestrictions = null ) {
2898                 $dbr = wfGetDB( DB_REPLICA );
2899
2900                 $restrictionTypes = $this->getRestrictionTypes();
2901
2902                 foreach ( $restrictionTypes as $type ) {
2903                         $this->mRestrictions[$type] = [];
2904                         $this->mRestrictionsExpiry[$type] = 'infinity';
2905                 }
2906
2907                 $this->mCascadeRestriction = false;
2908
2909                 # Backwards-compatibility: also load the restrictions from the page record (old format).
2910                 if ( $oldFashionedRestrictions !== null ) {
2911                         $this->mOldRestrictions = $oldFashionedRestrictions;
2912                 }
2913
2914                 if ( $this->mOldRestrictions === false ) {
2915                         $this->mOldRestrictions = $dbr->selectField( 'page', 'page_restrictions',
2916                                 [ 'page_id' => $this->getArticleID() ], __METHOD__ );
2917                 }
2918
2919                 if ( $this->mOldRestrictions != '' ) {
2920                         foreach ( explode( ':', trim( $this->mOldRestrictions ) ) as $restrict ) {
2921                                 $temp = explode( '=', trim( $restrict ) );
2922                                 if ( count( $temp ) == 1 ) {
2923                                         // old old format should be treated as edit/move restriction
2924                                         $this->mRestrictions['edit'] = explode( ',', trim( $temp[0] ) );
2925                                         $this->mRestrictions['move'] = explode( ',', trim( $temp[0] ) );
2926                                 } else {
2927                                         $restriction = trim( $temp[1] );
2928                                         if ( $restriction != '' ) { // some old entries are empty
2929                                                 $this->mRestrictions[$temp[0]] = explode( ',', $restriction );
2930                                         }
2931                                 }
2932                         }
2933                 }
2934
2935                 if ( count( $rows ) ) {
2936                         # Current system - load second to make them override.
2937                         $now = wfTimestampNow();
2938
2939                         # Cycle through all the restrictions.
2940                         foreach ( $rows as $row ) {
2941                                 // Don't take care of restrictions types that aren't allowed
2942                                 if ( !in_array( $row->pr_type, $restrictionTypes ) ) {
2943                                         continue;
2944                                 }
2945
2946                                 $expiry = $dbr->decodeExpiry( $row->pr_expiry );
2947
2948                                 // Only apply the restrictions if they haven't expired!
2949                                 if ( !$expiry || $expiry > $now ) {
2950                                         $this->mRestrictionsExpiry[$row->pr_type] = $expiry;
2951                                         $this->mRestrictions[$row->pr_type] = explode( ',', trim( $row->pr_level ) );
2952
2953                                         $this->mCascadeRestriction |= $row->pr_cascade;
2954                                 }
2955                         }
2956                 }
2957
2958                 $this->mRestrictionsLoaded = true;
2959         }
2960
2961         /**
2962          * Load restrictions from the page_restrictions table
2963          *
2964          * @param string $oldFashionedRestrictions Comma-separated list of page
2965          *   restrictions from page table (pre 1.10)
2966          */
2967         public function loadRestrictions( $oldFashionedRestrictions = null ) {
2968                 if ( $this->mRestrictionsLoaded ) {
2969                         return;
2970                 }
2971
2972                 $id = $this->getArticleID();
2973                 if ( $id ) {
2974                         $cache = ObjectCache::getMainWANInstance();
2975                         $rows = $cache->getWithSetCallback(
2976                                 // Page protections always leave a new null revision
2977                                 $cache->makeKey( 'page-restrictions', $id, $this->getLatestRevID() ),
2978                                 $cache::TTL_DAY,
2979                                 function ( $curValue, &$ttl, array &$setOpts ) {
2980                                         $dbr = wfGetDB( DB_REPLICA );
2981
2982                                         $setOpts += Database::getCacheSetOptions( $dbr );
2983
2984                                         return iterator_to_array(
2985                                                 $dbr->select(
2986                                                         'page_restrictions',
2987                                                         [ 'pr_type', 'pr_expiry', 'pr_level', 'pr_cascade' ],
2988                                                         [ 'pr_page' => $this->getArticleID() ],
2989                                                         __METHOD__
2990                                                 )
2991                                         );
2992                                 }
2993                         );
2994
2995                         $this->loadRestrictionsFromRows( $rows, $oldFashionedRestrictions );
2996                 } else {
2997                         $title_protection = $this->getTitleProtectionInternal();
2998
2999                         if ( $title_protection ) {
3000                                 $now = wfTimestampNow();
3001                                 $expiry = wfGetDB( DB_REPLICA )->decodeExpiry( $title_protection['expiry'] );
3002
3003                                 if ( !$expiry || $expiry > $now ) {
3004                                         // Apply the restrictions
3005                                         $this->mRestrictionsExpiry['create'] = $expiry;
3006                                         $this->mRestrictions['create'] =
3007                                                 explode( ',', trim( $title_protection['permission'] ) );
3008                                 } else { // Get rid of the old restrictions
3009                                         $this->mTitleProtection = false;
3010                                 }
3011                         } else {
3012                                 $this->mRestrictionsExpiry['create'] = 'infinity';
3013                         }
3014                         $this->mRestrictionsLoaded = true;
3015                 }
3016         }
3017
3018         /**
3019          * Flush the protection cache in this object and force reload from the database.
3020          * This is used when updating protection from WikiPage::doUpdateRestrictions().
3021          */
3022         public function flushRestrictions() {
3023                 $this->mRestrictionsLoaded = false;
3024                 $this->mTitleProtection = null;
3025         }
3026
3027         /**
3028          * Purge expired restrictions from the page_restrictions table
3029          *
3030          * This will purge no more than $wgUpdateRowsPerQuery page_restrictions rows
3031          */
3032         static function purgeExpiredRestrictions() {
3033                 if ( wfReadOnly() ) {
3034                         return;
3035                 }
3036
3037                 DeferredUpdates::addUpdate( new AtomicSectionUpdate(
3038                         wfGetDB( DB_MASTER ),
3039                         __METHOD__,
3040                         function ( IDatabase $dbw, $fname ) {
3041                                 $config = MediaWikiServices::getInstance()->getMainConfig();
3042                                 $ids = $dbw->selectFieldValues(
3043                                         'page_restrictions',
3044                                         'pr_id',
3045                                         [ 'pr_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ],
3046                                         $fname,
3047                                         [ 'LIMIT' => $config->get( 'UpdateRowsPerQuery' ) ] // T135470
3048                                 );
3049                                 if ( $ids ) {
3050                                         $dbw->delete( 'page_restrictions', [ 'pr_id' => $ids ], $fname );
3051                                 }
3052                         }
3053                 ) );
3054
3055                 DeferredUpdates::addUpdate( new AtomicSectionUpdate(
3056                         wfGetDB( DB_MASTER ),
3057                         __METHOD__,
3058                         function ( IDatabase $dbw, $fname ) {
3059                                 $dbw->delete(
3060                                         'protected_titles',
3061                                         [ 'pt_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ],
3062                                         $fname
3063                                 );
3064                         }
3065                 ) );
3066         }
3067
3068         /**
3069          * Does this have subpages?  (Warning, usually requires an extra DB query.)
3070          *
3071          * @return bool
3072          */
3073         public function hasSubpages() {
3074                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
3075                         # Duh
3076                         return false;
3077                 }
3078
3079                 # We dynamically add a member variable for the purpose of this method
3080                 # alone to cache the result.  There's no point in having it hanging
3081                 # around uninitialized in every Title object; therefore we only add it
3082                 # if needed and don't declare it statically.
3083                 if ( $this->mHasSubpages === null ) {
3084                         $this->mHasSubpages = false;
3085                         $subpages = $this->getSubpages( 1 );
3086                         if ( $subpages instanceof TitleArray ) {
3087                                 $this->mHasSubpages = (bool)$subpages->count();
3088                         }
3089                 }
3090
3091                 return $this->mHasSubpages;
3092         }
3093
3094         /**
3095          * Get all subpages of this page.
3096          *
3097          * @param int $limit Maximum number of subpages to fetch; -1 for no limit
3098          * @return TitleArray|array TitleArray, or empty array if this page's namespace
3099          *  doesn't allow subpages
3100          */
3101         public function getSubpages( $limit = -1 ) {
3102                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3103                         return [];
3104                 }
3105
3106                 $dbr = wfGetDB( DB_REPLICA );
3107                 $conds['page_namespace'] = $this->getNamespace();
3108                 $conds[] = 'page_title ' . $dbr->buildLike( $this->getDBkey() . '/', $dbr->anyString() );
3109                 $options = [];
3110                 if ( $limit > -1 ) {
3111                         $options['LIMIT'] = $limit;
3112                 }
3113                 $this->mSubpages = TitleArray::newFromResult(
3114                         $dbr->select( 'page',
3115                                 [ 'page_id', 'page_namespace', 'page_title', 'page_is_redirect' ],
3116                                 $conds,
3117                                 __METHOD__,
3118                                 $options
3119                         )
3120                 );
3121                 return $this->mSubpages;
3122         }
3123
3124         /**
3125          * Is there a version of this page in the deletion archive?
3126          *
3127          * @return int The number of archived revisions
3128          */
3129         public function isDeleted() {
3130                 if ( $this->getNamespace() < 0 ) {
3131                         $n = 0;
3132                 } else {
3133                         $dbr = wfGetDB( DB_REPLICA );
3134
3135                         $n = $dbr->selectField( 'archive', 'COUNT(*)',
3136                                 [ 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ],
3137                                 __METHOD__
3138                         );
3139                         if ( $this->getNamespace() == NS_FILE ) {
3140                                 $n += $dbr->selectField( 'filearchive', 'COUNT(*)',
3141                                         [ 'fa_name' => $this->getDBkey() ],
3142                                         __METHOD__
3143                                 );
3144                         }
3145                 }
3146                 return (int)$n;
3147         }
3148
3149         /**
3150          * Is there a version of this page in the deletion archive?
3151          *
3152          * @return bool
3153          */
3154         public function isDeletedQuick() {
3155                 if ( $this->getNamespace() < 0 ) {
3156                         return false;
3157                 }
3158                 $dbr = wfGetDB( DB_REPLICA );
3159                 $deleted = (bool)$dbr->selectField( 'archive', '1',
3160                         [ 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ],
3161                         __METHOD__
3162                 );
3163                 if ( !$deleted && $this->getNamespace() == NS_FILE ) {
3164                         $deleted = (bool)$dbr->selectField( 'filearchive', '1',
3165                                 [ 'fa_name' => $this->getDBkey() ],
3166                                 __METHOD__
3167                         );
3168                 }
3169                 return $deleted;
3170         }
3171
3172         /**
3173          * Get the article ID for this Title from the link cache,
3174          * adding it if necessary
3175          *
3176          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select
3177          *  for update
3178          * @return int The ID
3179          */
3180         public function getArticleID( $flags = 0 ) {
3181                 if ( $this->getNamespace() < 0 ) {
3182                         $this->mArticleID = 0;
3183                         return $this->mArticleID;
3184                 }
3185                 $linkCache = LinkCache::singleton();
3186                 if ( $flags & self::GAID_FOR_UPDATE ) {
3187                         $oldUpdate = $linkCache->forUpdate( true );
3188                         $linkCache->clearLink( $this );
3189                         $this->mArticleID = $linkCache->addLinkObj( $this );
3190                         $linkCache->forUpdate( $oldUpdate );
3191                 } else {
3192                         if ( -1 == $this->mArticleID ) {
3193                                 $this->mArticleID = $linkCache->addLinkObj( $this );
3194                         }
3195                 }
3196                 return $this->mArticleID;
3197         }
3198
3199         /**
3200          * Is this an article that is a redirect page?
3201          * Uses link cache, adding it if necessary
3202          *
3203          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3204          * @return bool
3205          */
3206         public function isRedirect( $flags = 0 ) {
3207                 if ( !is_null( $this->mRedirect ) ) {
3208                         return $this->mRedirect;
3209                 }
3210                 if ( !$this->getArticleID( $flags ) ) {
3211                         $this->mRedirect = false;
3212                         return $this->mRedirect;
3213                 }
3214
3215                 $linkCache = LinkCache::singleton();
3216                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3217                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'redirect' );
3218                 if ( $cached === null ) {
3219                         # Trust LinkCache's state over our own
3220                         # LinkCache is telling us that the page doesn't exist, despite there being cached
3221                         # data relating to an existing page in $this->mArticleID. Updaters should clear
3222                         # LinkCache as appropriate, or use $flags = Title::GAID_FOR_UPDATE. If that flag is
3223                         # set, then LinkCache will definitely be up to date here, since getArticleID() forces
3224                         # LinkCache to refresh its data from the master.
3225                         $this->mRedirect = false;
3226                         return $this->mRedirect;
3227                 }
3228
3229                 $this->mRedirect = (bool)$cached;
3230
3231                 return $this->mRedirect;
3232         }
3233
3234         /**
3235          * What is the length of this page?
3236          * Uses link cache, adding it if necessary
3237          *
3238          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3239          * @return int
3240          */
3241         public function getLength( $flags = 0 ) {
3242                 if ( $this->mLength != -1 ) {
3243                         return $this->mLength;
3244                 }
3245                 if ( !$this->getArticleID( $flags ) ) {
3246                         $this->mLength = 0;
3247                         return $this->mLength;
3248                 }
3249                 $linkCache = LinkCache::singleton();
3250                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3251                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'length' );
3252                 if ( $cached === null ) {
3253                         # Trust LinkCache's state over our own, as for isRedirect()
3254                         $this->mLength = 0;
3255                         return $this->mLength;
3256                 }
3257
3258                 $this->mLength = intval( $cached );
3259
3260                 return $this->mLength;
3261         }
3262
3263         /**
3264          * What is the page_latest field for this page?
3265          *
3266          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3267          * @return int Int or 0 if the page doesn't exist
3268          */
3269         public function getLatestRevID( $flags = 0 ) {
3270                 if ( !( $flags & Title::GAID_FOR_UPDATE ) && $this->mLatestID !== false ) {
3271                         return intval( $this->mLatestID );
3272                 }
3273                 if ( !$this->getArticleID( $flags ) ) {
3274                         $this->mLatestID = 0;
3275                         return $this->mLatestID;
3276                 }
3277                 $linkCache = LinkCache::singleton();
3278                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3279                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'revision' );
3280                 if ( $cached === null ) {
3281                         # Trust LinkCache's state over our own, as for isRedirect()
3282                         $this->mLatestID = 0;
3283                         return $this->mLatestID;
3284                 }
3285
3286                 $this->mLatestID = intval( $cached );
3287
3288                 return $this->mLatestID;
3289         }
3290
3291         /**
3292          * This clears some fields in this object, and clears any associated
3293          * keys in the "bad links" section of the link cache.
3294          *
3295          * - This is called from WikiPage::doEditContent() and WikiPage::insertOn() to allow
3296          * loading of the new page_id. It's also called from
3297          * WikiPage::doDeleteArticleReal()
3298          *
3299          * @param int $newid The new Article ID
3300          */
3301         public function resetArticleID( $newid ) {
3302                 $linkCache = LinkCache::singleton();
3303                 $linkCache->clearLink( $this );
3304
3305                 if ( $newid === false ) {
3306                         $this->mArticleID = -1;
3307                 } else {
3308                         $this->mArticleID = intval( $newid );
3309                 }
3310                 $this->mRestrictionsLoaded = false;
3311                 $this->mRestrictions = [];
3312                 $this->mOldRestrictions = false;
3313                 $this->mRedirect = null;
3314                 $this->mLength = -1;
3315                 $this->mLatestID = false;
3316                 $this->mContentModel = false;
3317                 $this->mEstimateRevisions = null;
3318                 $this->mPageLanguage = false;
3319                 $this->mDbPageLanguage = false;
3320                 $this->mIsBigDeletion = null;
3321         }
3322
3323         public static function clearCaches() {
3324                 $linkCache = LinkCache::singleton();
3325                 $linkCache->clear();
3326
3327                 $titleCache = self::getTitleCache();
3328                 $titleCache->clear();
3329         }
3330
3331         /**
3332          * Capitalize a text string for a title if it belongs to a namespace that capitalizes
3333          *
3334          * @param string $text Containing title to capitalize
3335          * @param int $ns Namespace index, defaults to NS_MAIN
3336          * @return string Containing capitalized title
3337          */
3338         public static function capitalize( $text, $ns = NS_MAIN ) {
3339                 global $wgContLang;
3340
3341                 if ( MWNamespace::isCapitalized( $ns ) ) {
3342                         return $wgContLang->ucfirst( $text );
3343                 } else {
3344                         return $text;
3345                 }
3346         }
3347
3348         /**
3349          * Secure and split - main initialisation function for this object
3350          *
3351          * Assumes that mDbkeyform has been set, and is urldecoded
3352          * and uses underscores, but not otherwise munged.  This function
3353          * removes illegal characters, splits off the interwiki and
3354          * namespace prefixes, sets the other forms, and canonicalizes
3355          * everything.
3356          *
3357          * @throws MalformedTitleException On invalid titles
3358          * @return bool True on success
3359          */
3360         private function secureAndSplit() {
3361                 # Initialisation
3362                 $this->mInterwiki = '';
3363                 $this->mFragment = '';
3364                 $this->mNamespace = $this->mDefaultNamespace; # Usually NS_MAIN
3365
3366                 $dbkey = $this->mDbkeyform;
3367
3368                 // @note: splitTitleString() is a temporary hack to allow MediaWikiTitleCodec to share
3369                 //        the parsing code with Title, while avoiding massive refactoring.
3370                 // @todo: get rid of secureAndSplit, refactor parsing code.
3371                 // @note: getTitleParser() returns a TitleParser implementation which does not have a
3372                 //        splitTitleString method, but the only implementation (MediaWikiTitleCodec) does
3373                 $titleCodec = MediaWikiServices::getInstance()->getTitleParser();
3374                 // MalformedTitleException can be thrown here
3375                 $parts = $titleCodec->splitTitleString( $dbkey, $this->getDefaultNamespace() );
3376
3377                 # Fill fields
3378                 $this->setFragment( '#' . $parts['fragment'] );
3379                 $this->mInterwiki = $parts['interwiki'];
3380                 $this->mLocalInterwiki = $parts['local_interwiki'];
3381                 $this->mNamespace = $parts['namespace'];
3382                 $this->mUserCaseDBKey = $parts['user_case_dbkey'];
3383
3384                 $this->mDbkeyform = $parts['dbkey'];
3385                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
3386                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
3387
3388                 # We already know that some pages won't be in the database!
3389                 if ( $this->isExternal() || $this->mNamespace == NS_SPECIAL ) {
3390                         $this->mArticleID = 0;
3391                 }
3392
3393                 return true;
3394         }
3395
3396         /**
3397          * Get an array of Title objects linking to this Title
3398          * Also stores the IDs in the link cache.
3399          *
3400          * WARNING: do not use this function on arbitrary user-supplied titles!
3401          * On heavily-used templates it will max out the memory.
3402          *
3403          * @param array $options May be FOR UPDATE
3404          * @param string $table Table name
3405          * @param string $prefix Fields prefix
3406          * @return Title[] Array of Title objects linking here
3407          */
3408         public function getLinksTo( $options = [], $table = 'pagelinks', $prefix = 'pl' ) {
3409                 if ( count( $options ) > 0 ) {
3410                         $db = wfGetDB( DB_MASTER );
3411                 } else {
3412                         $db = wfGetDB( DB_REPLICA );
3413                 }
3414
3415                 $res = $db->select(
3416                         [ 'page', $table ],
3417                         self::getSelectFields(),
3418                         [
3419                                 "{$prefix}_from=page_id",
3420                                 "{$prefix}_namespace" => $this->getNamespace(),
3421                                 "{$prefix}_title" => $this->getDBkey() ],
3422                         __METHOD__,
3423                         $options
3424                 );
3425
3426                 $retVal = [];
3427                 if ( $res->numRows() ) {
3428                         $linkCache = LinkCache::singleton();
3429                         foreach ( $res as $row ) {
3430                                 $titleObj = Title::makeTitle( $row->page_namespace, $row->page_title );
3431                                 if ( $titleObj ) {
3432                                         $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3433                                         $retVal[] = $titleObj;
3434                                 }
3435                         }
3436                 }
3437                 return $retVal;
3438         }
3439
3440         /**
3441          * Get an array of Title objects using this Title as a template
3442          * Also stores the IDs in the link cache.
3443          *
3444          * WARNING: do not use this function on arbitrary user-supplied titles!
3445          * On heavily-used templates it will max out the memory.
3446          *
3447          * @param array $options Query option to Database::select()
3448          * @return Title[] Array of Title the Title objects linking here
3449          */
3450         public function getTemplateLinksTo( $options = [] ) {
3451                 return $this->getLinksTo( $options, 'templatelinks', 'tl' );
3452         }
3453
3454         /**
3455          * Get an array of Title objects linked from this Title
3456          * Also stores the IDs in the link cache.
3457          *
3458          * WARNING: do not use this function on arbitrary user-supplied titles!
3459          * On heavily-used templates it will max out the memory.
3460          *
3461          * @param array $options Query option to Database::select()
3462          * @param string $table Table name
3463          * @param string $prefix Fields prefix
3464          * @return array Array of Title objects linking here
3465          */
3466         public function getLinksFrom( $options = [], $table = 'pagelinks', $prefix = 'pl' ) {
3467                 $id = $this->getArticleID();
3468
3469                 # If the page doesn't exist; there can't be any link from this page
3470                 if ( !$id ) {
3471                         return [];
3472                 }
3473
3474                 $db = wfGetDB( DB_REPLICA );
3475
3476                 $blNamespace = "{$prefix}_namespace";
3477                 $blTitle = "{$prefix}_title";
3478
3479                 $res = $db->select(
3480                         [ $table, 'page' ],
3481                         array_merge(
3482                                 [ $blNamespace, $blTitle ],
3483                                 WikiPage::selectFields()
3484                         ),
3485                         [ "{$prefix}_from" => $id ],
3486                         __METHOD__,
3487                         $options,
3488                         [ 'page' => [
3489                                 'LEFT JOIN',
3490                                 [ "page_namespace=$blNamespace", "page_title=$blTitle" ]
3491                         ] ]
3492                 );
3493
3494                 $retVal = [];
3495                 $linkCache = LinkCache::singleton();
3496                 foreach ( $res as $row ) {
3497                         if ( $row->page_id ) {
3498                                 $titleObj = Title::newFromRow( $row );
3499                         } else {
3500                                 $titleObj = Title::makeTitle( $row->$blNamespace, $row->$blTitle );
3501                                 $linkCache->addBadLinkObj( $titleObj );
3502                         }
3503                         $retVal[] = $titleObj;
3504                 }
3505
3506                 return $retVal;
3507         }
3508
3509         /**
3510          * Get an array of Title objects used on this Title as a template
3511          * Also stores the IDs in the link cache.
3512          *
3513          * WARNING: do not use this function on arbitrary user-supplied titles!
3514          * On heavily-used templates it will max out the memory.
3515          *
3516          * @param array $options May be FOR UPDATE
3517          * @return Title[] Array of Title the Title objects used here
3518          */
3519         public function getTemplateLinksFrom( $options = [] ) {
3520                 return $this->getLinksFrom( $options, 'templatelinks', 'tl' );
3521         }
3522
3523         /**
3524          * Get an array of Title objects referring to non-existent articles linked
3525          * from this page.
3526          *
3527          * @todo check if needed (used only in SpecialBrokenRedirects.php, and
3528          *   should use redirect table in this case).
3529          * @return Title[] Array of Title the Title objects
3530          */
3531         public function getBrokenLinksFrom() {
3532                 if ( $this->getArticleID() == 0 ) {
3533                         # All links from article ID 0 are false positives
3534                         return [];
3535                 }
3536
3537                 $dbr = wfGetDB( DB_REPLICA );
3538                 $res = $dbr->select(
3539                         [ 'page', 'pagelinks' ],
3540                         [ 'pl_namespace', 'pl_title' ],
3541                         [
3542                                 'pl_from' => $this->getArticleID(),
3543                                 'page_namespace IS NULL'
3544                         ],
3545                         __METHOD__, [],
3546                         [
3547                                 'page' => [
3548                                         'LEFT JOIN',
3549                                         [ 'pl_namespace=page_namespace', 'pl_title=page_title' ]
3550                                 ]
3551                         ]
3552                 );
3553
3554                 $retVal = [];
3555                 foreach ( $res as $row ) {
3556                         $retVal[] = Title::makeTitle( $row->pl_namespace, $row->pl_title );
3557                 }
3558                 return $retVal;
3559         }
3560
3561         /**
3562          * Get a list of URLs to purge from the CDN cache when this
3563          * page changes
3564          *
3565          * @return string[] Array of String the URLs
3566          */
3567         public function getCdnUrls() {
3568                 $urls = [
3569                         $this->getInternalURL(),
3570                         $this->getInternalURL( 'action=history' )
3571                 ];
3572
3573                 $pageLang = $this->getPageLanguage();
3574                 if ( $pageLang->hasVariants() ) {
3575                         $variants = $pageLang->getVariants();
3576                         foreach ( $variants as $vCode ) {
3577                                 $urls[] = $this->getInternalURL( $vCode );
3578                         }
3579                 }
3580
3581                 // If we are looking at a css/js user subpage, purge the action=raw.
3582                 if ( $this->isJsSubpage() ) {
3583                         $urls[] = $this->getInternalURL( 'action=raw&ctype=text/javascript' );
3584                 } elseif ( $this->isCssSubpage() ) {
3585                         $urls[] = $this->getInternalURL( 'action=raw&ctype=text/css' );
3586                 }
3587
3588                 Hooks::run( 'TitleSquidURLs', [ $this, &$urls ] );
3589                 return $urls;
3590         }
3591
3592         /**
3593          * @deprecated since 1.27 use getCdnUrls()
3594          */
3595         public function getSquidURLs() {
3596                 return $this->getCdnUrls();
3597         }
3598
3599         /**
3600          * Purge all applicable CDN URLs
3601          */
3602         public function purgeSquid() {
3603                 DeferredUpdates::addUpdate(
3604                         new CdnCacheUpdate( $this->getCdnUrls() ),
3605                         DeferredUpdates::PRESEND
3606                 );
3607         }
3608
3609         /**
3610          * Check whether a given move operation would be valid.
3611          * Returns true if ok, or a getUserPermissionsErrors()-like array otherwise
3612          *
3613          * @deprecated since 1.25, use MovePage's methods instead
3614          * @param Title $nt The new title
3615          * @param bool $auth Whether to check user permissions (uses $wgUser)
3616          * @param string $reason Is the log summary of the move, used for spam checking
3617          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3618          */
3619         public function isValidMoveOperation( &$nt, $auth = true, $reason = '' ) {
3620                 global $wgUser;
3621
3622                 if ( !( $nt instanceof Title ) ) {
3623                         // Normally we'd add this to $errors, but we'll get
3624                         // lots of syntax errors if $nt is not an object
3625                         return [ [ 'badtitletext' ] ];
3626                 }
3627
3628                 $mp = new MovePage( $this, $nt );
3629                 $errors = $mp->isValidMove()->getErrorsArray();
3630                 if ( $auth ) {
3631                         $errors = wfMergeErrorArrays(
3632                                 $errors,
3633                                 $mp->checkPermissions( $wgUser, $reason )->getErrorsArray()
3634                         );
3635                 }
3636
3637                 return $errors ?: true;
3638         }
3639
3640         /**
3641          * Check if the requested move target is a valid file move target
3642          * @todo move this to MovePage
3643          * @param Title $nt Target title
3644          * @return array List of errors
3645          */
3646         protected function validateFileMoveOperation( $nt ) {
3647                 global $wgUser;
3648
3649                 $errors = [];
3650
3651                 $destFile = wfLocalFile( $nt );
3652                 $destFile->load( File::READ_LATEST );
3653                 if ( !$wgUser->isAllowed( 'reupload-shared' )
3654                         && !$destFile->exists() && wfFindFile( $nt )
3655                 ) {
3656                         $errors[] = [ 'file-exists-sharedrepo' ];
3657                 }
3658
3659                 return $errors;
3660         }
3661
3662         /**
3663          * Move a title to a new location
3664          *
3665          * @deprecated since 1.25, use the MovePage class instead
3666          * @param Title $nt The new title
3667          * @param bool $auth Indicates whether $wgUser's permissions
3668          *  should be checked
3669          * @param string $reason The reason for the move
3670          * @param bool $createRedirect Whether to create a redirect from the old title to the new title.
3671          *  Ignored if the user doesn't have the suppressredirect right.
3672          * @param array $changeTags Applied to the entry in the move log and redirect page revision
3673          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3674          */
3675         public function moveTo( &$nt, $auth = true, $reason = '', $createRedirect = true,
3676                 array $changeTags = [] ) {
3677
3678                 global $wgUser;
3679                 $err = $this->isValidMoveOperation( $nt, $auth, $reason );
3680                 if ( is_array( $err ) ) {
3681                         // Auto-block user's IP if the account was "hard" blocked
3682                         $wgUser->spreadAnyEditBlock();
3683                         return $err;
3684                 }
3685                 // Check suppressredirect permission
3686                 if ( $auth && !$wgUser->isAllowed( 'suppressredirect' ) ) {
3687                         $createRedirect = true;
3688                 }
3689
3690                 $mp = new MovePage( $this, $nt );
3691                 $status = $mp->move( $wgUser, $reason, $createRedirect, $changeTags );
3692                 if ( $status->isOK() ) {
3693                         return true;
3694                 } else {
3695                         return $status->getErrorsArray();
3696                 }
3697         }
3698
3699         /**
3700          * Move this page's subpages to be subpages of $nt
3701          *
3702          * @param Title $nt Move target
3703          * @param bool $auth Whether $wgUser's permissions should be checked
3704          * @param string $reason The reason for the move
3705          * @param bool $createRedirect Whether to create redirects from the old subpages to
3706          *     the new ones Ignored if the user doesn't have the 'suppressredirect' right
3707          * @param array $changeTags Applied to the entry in the move log and redirect page revision
3708          * @return array Array with old page titles as keys, and strings (new page titles) or
3709          *     getUserPermissionsErrors()-like arrays (errors) as values, or a
3710          *     getUserPermissionsErrors()-like error array with numeric indices if
3711          *     no pages were moved
3712          */
3713         public function moveSubpages( $nt, $auth = true, $reason = '', $createRedirect = true,
3714                 array $changeTags = [] ) {
3715
3716                 global $wgMaximumMovedPages;
3717                 // Check permissions
3718                 if ( !$this->userCan( 'move-subpages' ) ) {
3719                         return [
3720                                 [ 'cant-move-subpages' ],
3721                         ];
3722                 }
3723                 // Do the source and target namespaces support subpages?
3724                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3725                         return [
3726                                 [ 'namespace-nosubpages', MWNamespace::getCanonicalName( $this->getNamespace() ) ],
3727                         ];
3728                 }
3729                 if ( !MWNamespace::hasSubpages( $nt->getNamespace() ) ) {
3730                         return [
3731                                 [ 'namespace-nosubpages', MWNamespace::getCanonicalName( $nt->getNamespace() ) ],
3732                         ];
3733                 }
3734
3735                 $subpages = $this->getSubpages( $wgMaximumMovedPages + 1 );
3736                 $retval = [];
3737                 $count = 0;
3738                 foreach ( $subpages as $oldSubpage ) {
3739                         $count++;
3740                         if ( $count > $wgMaximumMovedPages ) {
3741                                 $retval[$oldSubpage->getPrefixedText()] = [
3742                                         [ 'movepage-max-pages', $wgMaximumMovedPages ],
3743                                 ];
3744                                 break;
3745                         }
3746
3747                         // We don't know whether this function was called before
3748                         // or after moving the root page, so check both
3749                         // $this and $nt
3750                         if ( $oldSubpage->getArticleID() == $this->getArticleID()
3751                                 || $oldSubpage->getArticleID() == $nt->getArticleID()
3752                         ) {
3753                                 // When moving a page to a subpage of itself,
3754                                 // don't move it twice
3755                                 continue;
3756                         }
3757                         $newPageName = preg_replace(
3758                                         '#^' . preg_quote( $this->getDBkey(), '#' ) . '#',
3759                                         StringUtils::escapeRegexReplacement( $nt->getDBkey() ), # T23234
3760                                         $oldSubpage->getDBkey() );
3761                         if ( $oldSubpage->isTalkPage() ) {
3762                                 $newNs = $nt->getTalkPage()->getNamespace();
3763                         } else {
3764                                 $newNs = $nt->getSubjectPage()->getNamespace();
3765                         }
3766                         # T16385: we need makeTitleSafe because the new page names may
3767                         # be longer than 255 characters.
3768                         $newSubpage = Title::makeTitleSafe( $newNs, $newPageName );
3769
3770                         $success = $oldSubpage->moveTo( $newSubpage, $auth, $reason, $createRedirect, $changeTags );
3771                         if ( $success === true ) {
3772                                 $retval[$oldSubpage->getPrefixedText()] = $newSubpage->getPrefixedText();
3773                         } else {
3774                                 $retval[$oldSubpage->getPrefixedText()] = $success;
3775                         }
3776                 }
3777                 return $retval;
3778         }
3779
3780         /**
3781          * Checks if this page is just a one-rev redirect.
3782          * Adds lock, so don't use just for light purposes.
3783          *
3784          * @return bool
3785          */
3786         public function isSingleRevRedirect() {
3787                 global $wgContentHandlerUseDB;
3788
3789                 $dbw = wfGetDB( DB_MASTER );
3790
3791                 # Is it a redirect?
3792                 $fields = [ 'page_is_redirect', 'page_latest', 'page_id' ];
3793                 if ( $wgContentHandlerUseDB ) {
3794                         $fields[] = 'page_content_model';
3795                 }
3796
3797                 $row = $dbw->selectRow( 'page',
3798                         $fields,
3799                         $this->pageCond(),
3800                         __METHOD__,
3801                         [ 'FOR UPDATE' ]
3802                 );
3803                 # Cache some fields we may want
3804                 $this->mArticleID = $row ? intval( $row->page_id ) : 0;
3805                 $this->mRedirect = $row ? (bool)$row->page_is_redirect : false;
3806                 $this->mLatestID = $row ? intval( $row->page_latest ) : false;
3807                 $this->mContentModel = $row && isset( $row->page_content_model )
3808                         ? strval( $row->page_content_model )
3809                         : false;
3810
3811                 if ( !$this->mRedirect ) {
3812                         return false;
3813                 }
3814                 # Does the article have a history?
3815                 $row = $dbw->selectField( [ 'page', 'revision' ],
3816                         'rev_id',
3817                         [ 'page_namespace' => $this->getNamespace(),
3818                                 'page_title' => $this->getDBkey(),
3819                                 'page_id=rev_page',
3820                                 'page_latest != rev_id'
3821                         ],
3822                         __METHOD__,
3823                         [ 'FOR UPDATE' ]
3824                 );
3825                 # Return true if there was no history
3826                 return ( $row === false );
3827         }
3828
3829         /**
3830          * Checks if $this can be moved to a given Title
3831          * - Selects for update, so don't call it unless you mean business
3832          *
3833          * @deprecated since 1.25, use MovePage's methods instead
3834          * @param Title $nt The new title to check
3835          * @return bool
3836          */
3837         public function isValidMoveTarget( $nt ) {
3838                 # Is it an existing file?
3839                 if ( $nt->getNamespace() == NS_FILE ) {
3840                         $file = wfLocalFile( $nt );
3841                         $file->load( File::READ_LATEST );
3842                         if ( $file->exists() ) {
3843                                 wfDebug( __METHOD__ . ": file exists\n" );
3844                                 return false;
3845                         }
3846                 }
3847                 # Is it a redirect with no history?
3848                 if ( !$nt->isSingleRevRedirect() ) {
3849                         wfDebug( __METHOD__ . ": not a one-rev redirect\n" );
3850                         return false;
3851                 }
3852                 # Get the article text
3853                 $rev = Revision::newFromTitle( $nt, false, Revision::READ_LATEST );
3854                 if ( !is_object( $rev ) ) {
3855                         return false;
3856                 }
3857                 $content = $rev->getContent();
3858                 # Does the redirect point to the source?
3859                 # Or is it a broken self-redirect, usually caused by namespace collisions?
3860                 $redirTitle = $content ? $content->getRedirectTarget() : null;
3861
3862                 if ( $redirTitle ) {
3863                         if ( $redirTitle->getPrefixedDBkey() != $this->getPrefixedDBkey() &&
3864                                 $redirTitle->getPrefixedDBkey() != $nt->getPrefixedDBkey() ) {
3865                                 wfDebug( __METHOD__ . ": redirect points to other page\n" );
3866                                 return false;
3867                         } else {
3868                                 return true;
3869                         }
3870                 } else {
3871                         # Fail safe (not a redirect after all. strange.)
3872                         wfDebug( __METHOD__ . ": failsafe: database sais " . $nt->getPrefixedDBkey() .
3873                                                 " is a redirect, but it doesn't contain a valid redirect.\n" );
3874                         return false;
3875                 }
3876         }
3877
3878         /**
3879          * Get categories to which this Title belongs and return an array of
3880          * categories' names.
3881          *
3882          * @return array Array of parents in the form:
3883          *     $parent => $currentarticle
3884          */
3885         public function getParentCategories() {
3886                 global $wgContLang;
3887
3888                 $data = [];
3889
3890                 $titleKey = $this->getArticleID();
3891
3892                 if ( $titleKey === 0 ) {
3893                         return $data;
3894                 }
3895
3896                 $dbr = wfGetDB( DB_REPLICA );
3897
3898                 $res = $dbr->select(
3899                         'categorylinks',
3900                         'cl_to',
3901                         [ 'cl_from' => $titleKey ],
3902                         __METHOD__
3903                 );
3904
3905                 if ( $res->numRows() > 0 ) {
3906                         foreach ( $res as $row ) {
3907                                 // $data[] = Title::newFromText($wgContLang->getNsText ( NS_CATEGORY ).':'.$row->cl_to);
3908                                 $data[$wgContLang->getNsText( NS_CATEGORY ) . ':' . $row->cl_to] = $this->getFullText();
3909                         }
3910                 }
3911                 return $data;
3912         }
3913
3914         /**
3915          * Get a tree of parent categories
3916          *
3917          * @param array $children Array with the children in the keys, to check for circular refs
3918          * @return array Tree of parent categories
3919          */
3920         public function getParentCategoryTree( $children = [] ) {
3921                 $stack = [];
3922                 $parents = $this->getParentCategories();
3923
3924                 if ( $parents ) {
3925                         foreach ( $parents as $parent => $current ) {
3926                                 if ( array_key_exists( $parent, $children ) ) {
3927                                         # Circular reference
3928                                         $stack[$parent] = [];
3929                                 } else {
3930                                         $nt = Title::newFromText( $parent );
3931                                         if ( $nt ) {
3932                                                 $stack[$parent] = $nt->getParentCategoryTree( $children + [ $parent => 1 ] );
3933                                         }
3934                                 }
3935                         }
3936                 }
3937
3938                 return $stack;
3939         }
3940
3941         /**
3942          * Get an associative array for selecting this title from
3943          * the "page" table
3944          *
3945          * @return array Array suitable for the $where parameter of DB::select()
3946          */
3947         public function pageCond() {
3948                 if ( $this->mArticleID > 0 ) {
3949                         // PK avoids secondary lookups in InnoDB, shouldn't hurt other DBs
3950                         return [ 'page_id' => $this->mArticleID ];
3951                 } else {
3952                         return [ 'page_namespace' => $this->mNamespace, 'page_title' => $this->mDbkeyform ];
3953                 }
3954         }
3955
3956         /**
3957          * Get the revision ID of the previous revision
3958          *
3959          * @param int $revId Revision ID. Get the revision that was before this one.
3960          * @param int $flags Title::GAID_FOR_UPDATE
3961          * @return int|bool Old revision ID, or false if none exists
3962          */
3963         public function getPreviousRevisionID( $revId, $flags = 0 ) {
3964                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_REPLICA );
3965                 $revId = $db->selectField( 'revision', 'rev_id',
3966                         [
3967                                 'rev_page' => $this->getArticleID( $flags ),
3968                                 'rev_id < ' . intval( $revId )
3969                         ],
3970                         __METHOD__,
3971                         [ 'ORDER BY' => 'rev_id DESC' ]
3972                 );
3973
3974                 if ( $revId === false ) {
3975                         return false;
3976                 } else {
3977                         return intval( $revId );
3978                 }
3979         }
3980
3981         /**
3982          * Get the revision ID of the next revision
3983          *
3984          * @param int $revId Revision ID. Get the revision that was after this one.
3985          * @param int $flags Title::GAID_FOR_UPDATE
3986          * @return int|bool Next revision ID, or false if none exists
3987          */
3988         public function getNextRevisionID( $revId, $flags = 0 ) {
3989                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_REPLICA );
3990                 $revId = $db->selectField( 'revision', 'rev_id',
3991                         [
3992                                 'rev_page' => $this->getArticleID( $flags ),
3993                                 'rev_id > ' . intval( $revId )
3994                         ],
3995                         __METHOD__,
3996                         [ 'ORDER BY' => 'rev_id' ]
3997                 );
3998
3999                 if ( $revId === false ) {
4000                         return false;
4001                 } else {
4002                         return intval( $revId );
4003                 }
4004         }
4005
4006         /**
4007          * Get the first revision of the page
4008          *
4009          * @param int $flags Title::GAID_FOR_UPDATE
4010          * @return Revision|null If page doesn't exist
4011          */
4012         public function getFirstRevision( $flags = 0 ) {
4013                 $pageId = $this->getArticleID( $flags );
4014                 if ( $pageId ) {
4015                         $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_REPLICA );
4016                         $row = $db->selectRow( 'revision', Revision::selectFields(),
4017                                 [ 'rev_page' => $pageId ],
4018                                 __METHOD__,
4019                                 [ 'ORDER BY' => 'rev_timestamp ASC', 'LIMIT' => 1 ]
4020                         );
4021                         if ( $row ) {
4022                                 return new Revision( $row );
4023                         }
4024                 }
4025                 return null;
4026         }
4027
4028         /**
4029          * Get the oldest revision timestamp of this page
4030          *
4031          * @param int $flags Title::GAID_FOR_UPDATE
4032          * @return string MW timestamp
4033          */
4034         public function getEarliestRevTime( $flags = 0 ) {
4035                 $rev = $this->getFirstRevision( $flags );
4036                 return $rev ? $rev->getTimestamp() : null;
4037         }
4038
4039         /**
4040          * Check if this is a new page
4041          *
4042          * @return bool
4043          */
4044         public function isNewPage() {
4045                 $dbr = wfGetDB( DB_REPLICA );
4046                 return (bool)$dbr->selectField( 'page', 'page_is_new', $this->pageCond(), __METHOD__ );
4047         }
4048
4049         /**
4050          * Check whether the number of revisions of this page surpasses $wgDeleteRevisionsLimit
4051          *
4052          * @return bool
4053          */
4054         public function isBigDeletion() {
4055                 global $wgDeleteRevisionsLimit;
4056
4057                 if ( !$wgDeleteRevisionsLimit ) {
4058                         return false;
4059                 }
4060
4061                 if ( $this->mIsBigDeletion === null ) {
4062                         $dbr = wfGetDB( DB_REPLICA );
4063
4064                         $revCount = $dbr->selectRowCount(
4065                                 'revision',
4066                                 '1',
4067                                 [ 'rev_page' => $this->getArticleID() ],
4068                                 __METHOD__,
4069                                 [ 'LIMIT' => $wgDeleteRevisionsLimit + 1 ]
4070                         );
4071
4072                         $this->mIsBigDeletion = $revCount > $wgDeleteRevisionsLimit;
4073                 }
4074
4075                 return $this->mIsBigDeletion;
4076         }
4077
4078         /**
4079          * Get the approximate revision count of this page.
4080          *
4081          * @return int
4082          */
4083         public function estimateRevisionCount() {
4084                 if ( !$this->exists() ) {
4085                         return 0;
4086                 }
4087
4088                 if ( $this->mEstimateRevisions === null ) {
4089                         $dbr = wfGetDB( DB_REPLICA );
4090                         $this->mEstimateRevisions = $dbr->estimateRowCount( 'revision', '*',
4091                                 [ 'rev_page' => $this->getArticleID() ], __METHOD__ );
4092                 }
4093
4094                 return $this->mEstimateRevisions;
4095         }
4096
4097         /**
4098          * Get the number of revisions between the given revision.
4099          * Used for diffs and other things that really need it.
4100          *
4101          * @param int|Revision $old Old revision or rev ID (first before range)
4102          * @param int|Revision $new New revision or rev ID (first after range)
4103          * @param int|null $max Limit of Revisions to count, will be incremented to detect truncations
4104          * @return int Number of revisions between these revisions.
4105          */
4106         public function countRevisionsBetween( $old, $new, $max = null ) {
4107                 if ( !( $old instanceof Revision ) ) {
4108                         $old = Revision::newFromTitle( $this, (int)$old );
4109                 }
4110                 if ( !( $new instanceof Revision ) ) {
4111                         $new = Revision::newFromTitle( $this, (int)$new );
4112                 }
4113                 if ( !$old || !$new ) {
4114                         return 0; // nothing to compare
4115                 }
4116                 $dbr = wfGetDB( DB_REPLICA );
4117                 $conds = [
4118                         'rev_page' => $this->getArticleID(),
4119                         'rev_timestamp > ' . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4120                         'rev_timestamp < ' . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4121                 ];
4122                 if ( $max !== null ) {
4123                         return $dbr->selectRowCount( 'revision', '1',
4124                                 $conds,
4125                                 __METHOD__,
4126                                 [ 'LIMIT' => $max + 1 ] // extra to detect truncation
4127                         );
4128                 } else {
4129                         return (int)$dbr->selectField( 'revision', 'count(*)', $conds, __METHOD__ );
4130                 }
4131         }
4132
4133         /**
4134          * Get the authors between the given revisions or revision IDs.
4135          * Used for diffs and other things that really need it.
4136          *
4137          * @since 1.23
4138          *
4139          * @param int|Revision $old Old revision or rev ID (first before range by default)
4140          * @param int|Revision $new New revision or rev ID (first after range by default)
4141          * @param int $limit Maximum number of authors
4142          * @param string|array $options (Optional): Single option, or an array of options:
4143          *     'include_old' Include $old in the range; $new is excluded.
4144          *     'include_new' Include $new in the range; $old is excluded.
4145          *     'include_both' Include both $old and $new in the range.
4146          *     Unknown option values are ignored.
4147          * @return array|null Names of revision authors in the range; null if not both revisions exist
4148          */
4149         public function getAuthorsBetween( $old, $new, $limit, $options = [] ) {
4150                 if ( !( $old instanceof Revision ) ) {
4151                         $old = Revision::newFromTitle( $this, (int)$old );
4152                 }
4153                 if ( !( $new instanceof Revision ) ) {
4154                         $new = Revision::newFromTitle( $this, (int)$new );
4155                 }
4156                 // XXX: what if Revision objects are passed in, but they don't refer to this title?
4157                 // Add $old->getPage() != $new->getPage() || $old->getPage() != $this->getArticleID()
4158                 // in the sanity check below?
4159                 if ( !$old || !$new ) {
4160                         return null; // nothing to compare
4161                 }
4162                 $authors = [];
4163                 $old_cmp = '>';
4164                 $new_cmp = '<';
4165                 $options = (array)$options;
4166                 if ( in_array( 'include_old', $options ) ) {
4167                         $old_cmp = '>=';
4168                 }
4169                 if ( in_array( 'include_new', $options ) ) {
4170                         $new_cmp = '<=';
4171                 }
4172                 if ( in_array( 'include_both', $options ) ) {
4173                         $old_cmp = '>=';
4174                         $new_cmp = '<=';
4175                 }
4176                 // No DB query needed if $old and $new are the same or successive revisions:
4177                 if ( $old->getId() === $new->getId() ) {
4178                         return ( $old_cmp === '>' && $new_cmp === '<' ) ?
4179                                 [] :
4180                                 [ $old->getUserText( Revision::RAW ) ];
4181                 } elseif ( $old->getId() === $new->getParentId() ) {
4182                         if ( $old_cmp === '>=' && $new_cmp === '<=' ) {
4183                                 $authors[] = $old->getUserText( Revision::RAW );
4184                                 if ( $old->getUserText( Revision::RAW ) != $new->getUserText( Revision::RAW ) ) {
4185                                         $authors[] = $new->getUserText( Revision::RAW );
4186                                 }
4187                         } elseif ( $old_cmp === '>=' ) {
4188                                 $authors[] = $old->getUserText( Revision::RAW );
4189                         } elseif ( $new_cmp === '<=' ) {
4190                                 $authors[] = $new->getUserText( Revision::RAW );
4191                         }
4192                         return $authors;
4193                 }
4194                 $dbr = wfGetDB( DB_REPLICA );
4195                 $res = $dbr->select( 'revision', 'DISTINCT rev_user_text',
4196                         [
4197                                 'rev_page' => $this->getArticleID(),
4198                                 "rev_timestamp $old_cmp " . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4199                                 "rev_timestamp $new_cmp " . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4200                         ], __METHOD__,
4201                         [ 'LIMIT' => $limit + 1 ] // add one so caller knows it was truncated
4202                 );
4203                 foreach ( $res as $row ) {
4204                         $authors[] = $row->rev_user_text;
4205                 }
4206                 return $authors;
4207         }
4208
4209         /**
4210          * Get the number of authors between the given revisions or revision IDs.
4211          * Used for diffs and other things that really need it.
4212          *
4213          * @param int|Revision $old Old revision or rev ID (first before range by default)
4214          * @param int|Revision $new New revision or rev ID (first after range by default)
4215          * @param int $limit Maximum number of authors
4216          * @param string|array $options (Optional): Single option, or an array of options:
4217          *     'include_old' Include $old in the range; $new is excluded.
4218          *     'include_new' Include $new in the range; $old is excluded.
4219          *     'include_both' Include both $old and $new in the range.
4220          *     Unknown option values are ignored.
4221          * @return int Number of revision authors in the range; zero if not both revisions exist
4222          */
4223         public function countAuthorsBetween( $old, $new, $limit, $options = [] ) {
4224                 $authors = $this->getAuthorsBetween( $old, $new, $limit, $options );
4225                 return $authors ? count( $authors ) : 0;
4226         }
4227
4228         /**
4229          * Compare with another title.
4230          *
4231          * @param Title $title
4232          * @return bool
4233          */
4234         public function equals( Title $title ) {
4235                 // Note: === is necessary for proper matching of number-like titles.
4236                 return $this->getInterwiki() === $title->getInterwiki()
4237                         && $this->getNamespace() == $title->getNamespace()
4238                         && $this->getDBkey() === $title->getDBkey();
4239         }
4240
4241         /**
4242          * Check if this title is a subpage of another title
4243          *
4244          * @param Title $title
4245          * @return bool
4246          */
4247         public function isSubpageOf( Title $title ) {
4248                 return $this->getInterwiki() === $title->getInterwiki()
4249                         && $this->getNamespace() == $title->getNamespace()
4250                         && strpos( $this->getDBkey(), $title->getDBkey() . '/' ) === 0;
4251         }
4252
4253         /**
4254          * Check if page exists.  For historical reasons, this function simply
4255          * checks for the existence of the title in the page table, and will
4256          * thus return false for interwiki links, special pages and the like.
4257          * If you want to know if a title can be meaningfully viewed, you should
4258          * probably call the isKnown() method instead.
4259          *
4260          * @param int $flags An optional bit field; may be Title::GAID_FOR_UPDATE to check
4261          *   from master/for update
4262          * @return bool
4263          */
4264         public function exists( $flags = 0 ) {
4265                 $exists = $this->getArticleID( $flags ) != 0;
4266                 Hooks::run( 'TitleExists', [ $this, &$exists ] );
4267                 return $exists;
4268         }
4269
4270         /**
4271          * Should links to this title be shown as potentially viewable (i.e. as
4272          * "bluelinks"), even if there's no record by this title in the page
4273          * table?
4274          *
4275          * This function is semi-deprecated for public use, as well as somewhat
4276          * misleadingly named.  You probably just want to call isKnown(), which
4277          * calls this function internally.
4278          *
4279          * (ISSUE: Most of these checks are cheap, but the file existence check
4280          * can potentially be quite expensive.  Including it here fixes a lot of
4281          * existing code, but we might want to add an optional parameter to skip
4282          * it and any other expensive checks.)
4283          *
4284          * @return bool
4285          */
4286         public function isAlwaysKnown() {
4287                 $isKnown = null;
4288
4289                 /**
4290                  * Allows overriding default behavior for determining if a page exists.
4291                  * If $isKnown is kept as null, regular checks happen. If it's
4292                  * a boolean, this value is returned by the isKnown method.
4293                  *
4294                  * @since 1.20
4295                  *
4296                  * @param Title $title
4297                  * @param bool|null $isKnown
4298                  */
4299                 Hooks::run( 'TitleIsAlwaysKnown', [ $this, &$isKnown ] );
4300
4301                 if ( !is_null( $isKnown ) ) {
4302                         return $isKnown;
4303                 }
4304
4305                 if ( $this->isExternal() ) {
4306                         return true;  // any interwiki link might be viewable, for all we know
4307                 }
4308
4309                 switch ( $this->mNamespace ) {
4310                         case NS_MEDIA:
4311                         case NS_FILE:
4312                                 // file exists, possibly in a foreign repo
4313                                 return (bool)wfFindFile( $this );
4314                         case NS_SPECIAL:
4315                                 // valid special page
4316                                 return SpecialPageFactory::exists( $this->getDBkey() );
4317                         case NS_MAIN:
4318                                 // selflink, possibly with fragment
4319                                 return $this->mDbkeyform == '';
4320                         case NS_MEDIAWIKI:
4321                                 // known system message
4322                                 return $this->hasSourceText() !== false;
4323                         default:
4324                                 return false;
4325                 }
4326         }
4327
4328         /**
4329          * Does this title refer to a page that can (or might) be meaningfully
4330          * viewed?  In particular, this function may be used to determine if
4331          * links to the title should be rendered as "bluelinks" (as opposed to
4332          * "redlinks" to non-existent pages).
4333          * Adding something else to this function will cause inconsistency
4334          * since LinkHolderArray calls isAlwaysKnown() and does its own
4335          * page existence check.
4336          *
4337          * @return bool
4338          */
4339         public function isKnown() {
4340                 return $this->isAlwaysKnown() || $this->exists();
4341         }
4342
4343         /**
4344          * Does this page have source text?
4345          *
4346          * @return bool
4347          */
4348         public function hasSourceText() {
4349                 if ( $this->exists() ) {
4350                         return true;
4351                 }
4352
4353                 if ( $this->mNamespace == NS_MEDIAWIKI ) {
4354                         // If the page doesn't exist but is a known system message, default
4355                         // message content will be displayed, same for language subpages-
4356                         // Use always content language to avoid loading hundreds of languages
4357                         // to get the link color.
4358                         global $wgContLang;
4359                         list( $name, ) = MessageCache::singleton()->figureMessage(
4360                                 $wgContLang->lcfirst( $this->getText() )
4361                         );
4362                         $message = wfMessage( $name )->inLanguage( $wgContLang )->useDatabase( false );
4363                         return $message->exists();
4364                 }
4365
4366                 return false;
4367         }
4368
4369         /**
4370          * Get the default message text or false if the message doesn't exist
4371          *
4372          * @return string|bool
4373          */
4374         public function getDefaultMessageText() {
4375                 global $wgContLang;
4376
4377                 if ( $this->getNamespace() != NS_MEDIAWIKI ) { // Just in case
4378                         return false;
4379                 }
4380
4381                 list( $name, $lang ) = MessageCache::singleton()->figureMessage(
4382                         $wgContLang->lcfirst( $this->getText() )
4383                 );
4384                 $message = wfMessage( $name )->inLanguage( $lang )->useDatabase( false );
4385
4386                 if ( $message->exists() ) {
4387                         return $message->plain();
4388                 } else {
4389                         return false;
4390                 }
4391         }
4392
4393         /**
4394          * Updates page_touched for this page; called from LinksUpdate.php
4395          *
4396          * @param string $purgeTime [optional] TS_MW timestamp
4397          * @return bool True if the update succeeded
4398          */
4399         public function invalidateCache( $purgeTime = null ) {
4400                 if ( wfReadOnly() ) {
4401                         return false;
4402                 } elseif ( $this->mArticleID === 0 ) {
4403                         return true; // avoid gap locking if we know it's not there
4404                 }
4405
4406                 $dbw = wfGetDB( DB_MASTER );
4407                 $dbw->onTransactionPreCommitOrIdle( function () {
4408                         ResourceLoaderWikiModule::invalidateModuleCache( $this, null, null, wfWikiID() );
4409                 } );
4410
4411                 $conds = $this->pageCond();
4412                 DeferredUpdates::addUpdate(
4413                         new AutoCommitUpdate(
4414                                 $dbw,
4415                                 __METHOD__,
4416                                 function ( IDatabase $dbw, $fname ) use ( $conds, $purgeTime ) {
4417                                         $dbTimestamp = $dbw->timestamp( $purgeTime ?: time() );
4418                                         $dbw->update(
4419                                                 'page',
4420                                                 [ 'page_touched' => $dbTimestamp ],
4421                                                 $conds + [ 'page_touched < ' . $dbw->addQuotes( $dbTimestamp ) ],
4422                                                 $fname
4423                                         );
4424                                         MediaWikiServices::getInstance()->getLinkCache()->invalidateTitle( $this );
4425                                 }
4426                         ),
4427                         DeferredUpdates::PRESEND
4428                 );
4429
4430                 return true;
4431         }
4432
4433         /**
4434          * Update page_touched timestamps and send CDN purge messages for
4435          * pages linking to this title. May be sent to the job queue depending
4436          * on the number of links. Typically called on create and delete.
4437          */
4438         public function touchLinks() {
4439                 DeferredUpdates::addUpdate( new HTMLCacheUpdate( $this, 'pagelinks' ) );
4440                 if ( $this->getNamespace() == NS_CATEGORY ) {
4441                         DeferredUpdates::addUpdate( new HTMLCacheUpdate( $this, 'categorylinks' ) );
4442                 }
4443         }
4444
4445         /**
4446          * Get the last touched timestamp
4447          *
4448          * @param IDatabase $db Optional db
4449          * @return string|false Last-touched timestamp
4450          */
4451         public function getTouched( $db = null ) {
4452                 if ( $db === null ) {
4453                         $db = wfGetDB( DB_REPLICA );
4454                 }
4455                 $touched = $db->selectField( 'page', 'page_touched', $this->pageCond(), __METHOD__ );
4456                 return $touched;
4457         }
4458
4459         /**
4460          * Get the timestamp when this page was updated since the user last saw it.
4461          *
4462          * @param User $user
4463          * @return string|null
4464          */
4465         public function getNotificationTimestamp( $user = null ) {
4466                 global $wgUser;
4467
4468                 // Assume current user if none given
4469                 if ( !$user ) {
4470                         $user = $wgUser;
4471                 }
4472                 // Check cache first
4473                 $uid = $user->getId();
4474                 if ( !$uid ) {
4475                         return false;
4476                 }
4477                 // avoid isset here, as it'll return false for null entries
4478                 if ( array_key_exists( $uid, $this->mNotificationTimestamp ) ) {
4479                         return $this->mNotificationTimestamp[$uid];
4480                 }
4481                 // Don't cache too much!
4482                 if ( count( $this->mNotificationTimestamp ) >= self::CACHE_MAX ) {
4483                         $this->mNotificationTimestamp = [];
4484                 }
4485
4486                 $store = MediaWikiServices::getInstance()->getWatchedItemStore();
4487                 $watchedItem = $store->getWatchedItem( $user, $this );
4488                 if ( $watchedItem ) {
4489                         $this->mNotificationTimestamp[$uid] = $watchedItem->getNotificationTimestamp();
4490                 } else {
4491                         $this->mNotificationTimestamp[$uid] = false;
4492                 }
4493
4494                 return $this->mNotificationTimestamp[$uid];
4495         }
4496
4497         /**
4498          * Generate strings used for xml 'id' names in monobook tabs
4499          *
4500          * @param string $prepend Defaults to 'nstab-'
4501          * @return string XML 'id' name
4502          */
4503         public function getNamespaceKey( $prepend = 'nstab-' ) {
4504                 global $wgContLang;
4505                 // Gets the subject namespace if this title
4506                 $namespace = MWNamespace::getSubject( $this->getNamespace() );
4507                 // Checks if canonical namespace name exists for namespace
4508                 if ( MWNamespace::exists( $this->getNamespace() ) ) {
4509                         // Uses canonical namespace name
4510                         $namespaceKey = MWNamespace::getCanonicalName( $namespace );
4511                 } else {
4512                         // Uses text of namespace
4513                         $namespaceKey = $this->getSubjectNsText();
4514                 }
4515                 // Makes namespace key lowercase
4516                 $namespaceKey = $wgContLang->lc( $namespaceKey );
4517                 // Uses main
4518                 if ( $namespaceKey == '' ) {
4519                         $namespaceKey = 'main';
4520                 }
4521                 // Changes file to image for backwards compatibility
4522                 if ( $namespaceKey == 'file' ) {
4523                         $namespaceKey = 'image';
4524                 }
4525                 return $prepend . $namespaceKey;
4526         }
4527
4528         /**
4529          * Get all extant redirects to this Title
4530          *
4531          * @param int|null $ns Single namespace to consider; null to consider all namespaces
4532          * @return Title[] Array of Title redirects to this title
4533          */
4534         public function getRedirectsHere( $ns = null ) {
4535                 $redirs = [];
4536
4537                 $dbr = wfGetDB( DB_REPLICA );
4538                 $where = [
4539                         'rd_namespace' => $this->getNamespace(),
4540                         'rd_title' => $this->getDBkey(),
4541                         'rd_from = page_id'
4542                 ];
4543                 if ( $this->isExternal() ) {
4544                         $where['rd_interwiki'] = $this->getInterwiki();
4545                 } else {
4546                         $where[] = 'rd_interwiki = ' . $dbr->addQuotes( '' ) . ' OR rd_interwiki IS NULL';
4547                 }
4548                 if ( !is_null( $ns ) ) {
4549                         $where['page_namespace'] = $ns;
4550                 }
4551
4552                 $res = $dbr->select(
4553                         [ 'redirect', 'page' ],
4554                         [ 'page_namespace', 'page_title' ],
4555                         $where,
4556                         __METHOD__
4557                 );
4558
4559                 foreach ( $res as $row ) {
4560                         $redirs[] = self::newFromRow( $row );
4561                 }
4562                 return $redirs;
4563         }
4564
4565         /**
4566          * Check if this Title is a valid redirect target
4567          *
4568          * @return bool
4569          */
4570         public function isValidRedirectTarget() {
4571                 global $wgInvalidRedirectTargets;
4572
4573                 if ( $this->isSpecialPage() ) {
4574                         // invalid redirect targets are stored in a global array, but explicitly disallow Userlogout here
4575                         if ( $this->isSpecial( 'Userlogout' ) ) {
4576                                 return false;
4577                         }
4578
4579                         foreach ( $wgInvalidRedirectTargets as $target ) {
4580                                 if ( $this->isSpecial( $target ) ) {
4581                                         return false;
4582                                 }
4583                         }
4584                 }
4585
4586                 return true;
4587         }
4588
4589         /**
4590          * Get a backlink cache object
4591          *
4592          * @return BacklinkCache
4593          */
4594         public function getBacklinkCache() {
4595                 return BacklinkCache::get( $this );
4596         }
4597
4598         /**
4599          * Whether the magic words __INDEX__ and __NOINDEX__ function for  this page.
4600          *
4601          * @return bool
4602          */
4603         public function canUseNoindex() {
4604                 global $wgExemptFromUserRobotsControl;
4605
4606                 $bannedNamespaces = is_null( $wgExemptFromUserRobotsControl )
4607                         ? MWNamespace::getContentNamespaces()
4608                         : $wgExemptFromUserRobotsControl;
4609
4610                 return !in_array( $this->mNamespace, $bannedNamespaces );
4611         }
4612
4613         /**
4614          * Returns the raw sort key to be used for categories, with the specified
4615          * prefix.  This will be fed to Collation::getSortKey() to get a
4616          * binary sortkey that can be used for actual sorting.
4617          *
4618          * @param string $prefix The prefix to be used, specified using
4619          *   {{defaultsort:}} or like [[Category:Foo|prefix]].  Empty for no
4620          *   prefix.
4621          * @return string
4622          */
4623         public function getCategorySortkey( $prefix = '' ) {
4624                 $unprefixed = $this->getText();
4625
4626                 // Anything that uses this hook should only depend
4627                 // on the Title object passed in, and should probably
4628                 // tell the users to run updateCollations.php --force
4629                 // in order to re-sort existing category relations.
4630                 Hooks::run( 'GetDefaultSortkey', [ $this, &$unprefixed ] );
4631                 if ( $prefix !== '' ) {
4632                         # Separate with a line feed, so the unprefixed part is only used as
4633                         # a tiebreaker when two pages have the exact same prefix.
4634                         # In UCA, tab is the only character that can sort above LF
4635                         # so we strip both of them from the original prefix.
4636                         $prefix = strtr( $prefix, "\n\t", '  ' );
4637                         return "$prefix\n$unprefixed";
4638                 }
4639                 return $unprefixed;
4640         }
4641
4642         /**
4643          * Returns the page language code saved in the database, if $wgPageLanguageUseDB is set
4644          * to true in LocalSettings.php, otherwise returns false. If there is no language saved in
4645          * the db, it will return NULL.
4646          *
4647          * @return string|null|bool
4648          */
4649         private function getDbPageLanguageCode() {
4650                 global $wgPageLanguageUseDB;
4651
4652                 // check, if the page language could be saved in the database, and if so and
4653                 // the value is not requested already, lookup the page language using LinkCache
4654                 if ( $wgPageLanguageUseDB && $this->mDbPageLanguage === false ) {
4655                         $linkCache = LinkCache::singleton();
4656                         $linkCache->addLinkObj( $this );
4657                         $this->mDbPageLanguage = $linkCache->getGoodLinkFieldObj( $this, 'lang' );
4658                 }
4659
4660                 return $this->mDbPageLanguage;
4661         }
4662
4663         /**
4664          * Get the language in which the content of this page is written in
4665          * wikitext. Defaults to $wgContLang, but in certain cases it can be
4666          * e.g. $wgLang (such as special pages, which are in the user language).
4667          *
4668          * @since 1.18
4669          * @return Language
4670          */
4671         public function getPageLanguage() {
4672                 global $wgLang, $wgLanguageCode;
4673                 if ( $this->isSpecialPage() ) {
4674                         // special pages are in the user language
4675                         return $wgLang;
4676                 }
4677
4678                 // Checking if DB language is set
4679                 $dbPageLanguage = $this->getDbPageLanguageCode();
4680                 if ( $dbPageLanguage ) {
4681                         return wfGetLangObj( $dbPageLanguage );
4682                 }
4683
4684                 if ( !$this->mPageLanguage || $this->mPageLanguage[1] !== $wgLanguageCode ) {
4685                         // Note that this may depend on user settings, so the cache should
4686                         // be only per-request.
4687                         // NOTE: ContentHandler::getPageLanguage() may need to load the
4688                         // content to determine the page language!
4689                         // Checking $wgLanguageCode hasn't changed for the benefit of unit
4690                         // tests.
4691                         $contentHandler = ContentHandler::getForTitle( $this );
4692                         $langObj = $contentHandler->getPageLanguage( $this );
4693                         $this->mPageLanguage = [ $langObj->getCode(), $wgLanguageCode ];
4694                 } else {
4695                         $langObj = wfGetLangObj( $this->mPageLanguage[0] );
4696                 }
4697
4698                 return $langObj;
4699         }
4700
4701         /**
4702          * Get the language in which the content of this page is written when
4703          * viewed by user. Defaults to $wgContLang, but in certain cases it can be
4704          * e.g. $wgLang (such as special pages, which are in the user language).
4705          *
4706          * @since 1.20
4707          * @return Language
4708          */
4709         public function getPageViewLanguage() {
4710                 global $wgLang;
4711
4712                 if ( $this->isSpecialPage() ) {
4713                         // If the user chooses a variant, the content is actually
4714                         // in a language whose code is the variant code.
4715                         $variant = $wgLang->getPreferredVariant();
4716                         if ( $wgLang->getCode() !== $variant ) {
4717                                 return Language::factory( $variant );
4718                         }
4719
4720                         return $wgLang;
4721                 }
4722
4723                 // Checking if DB language is set
4724                 $dbPageLanguage = $this->getDbPageLanguageCode();
4725                 if ( $dbPageLanguage ) {
4726                         $pageLang = wfGetLangObj( $dbPageLanguage );
4727                         $variant = $pageLang->getPreferredVariant();
4728                         if ( $pageLang->getCode() !== $variant ) {
4729                                 $pageLang = Language::factory( $variant );
4730                         }
4731
4732                         return $pageLang;
4733                 }
4734
4735                 // @note Can't be cached persistently, depends on user settings.
4736                 // @note ContentHandler::getPageViewLanguage() may need to load the
4737                 //   content to determine the page language!
4738                 $contentHandler = ContentHandler::getForTitle( $this );
4739                 $pageLang = $contentHandler->getPageViewLanguage( $this );
4740                 return $pageLang;
4741         }
4742
4743         /**
4744          * Get a list of rendered edit notices for this page.
4745          *
4746          * Array is keyed by the original message key, and values are rendered using parseAsBlock, so
4747          * they will already be wrapped in paragraphs.
4748          *
4749          * @since 1.21
4750          * @param int $oldid Revision ID that's being edited
4751          * @return array
4752          */
4753         public function getEditNotices( $oldid = 0 ) {
4754                 $notices = [];
4755
4756                 // Optional notice for the entire namespace
4757                 $editnotice_ns = 'editnotice-' . $this->getNamespace();
4758                 $msg = wfMessage( $editnotice_ns );
4759                 if ( $msg->exists() ) {
4760                         $html = $msg->parseAsBlock();
4761                         // Edit notices may have complex logic, but output nothing (T91715)
4762                         if ( trim( $html ) !== '' ) {
4763                                 $notices[$editnotice_ns] = Html::rawElement(
4764                                         'div',
4765                                         [ 'class' => [
4766                                                 'mw-editnotice',
4767                                                 'mw-editnotice-namespace',
4768                                                 Sanitizer::escapeClass( "mw-$editnotice_ns" )
4769                                         ] ],
4770                                         $html
4771                                 );
4772                         }
4773                 }
4774
4775                 if ( MWNamespace::hasSubpages( $this->getNamespace() ) ) {
4776                         // Optional notice for page itself and any parent page
4777                         $parts = explode( '/', $this->getDBkey() );
4778                         $editnotice_base = $editnotice_ns;
4779                         while ( count( $parts ) > 0 ) {
4780                                 $editnotice_base .= '-' . array_shift( $parts );
4781                                 $msg = wfMessage( $editnotice_base );
4782                                 if ( $msg->exists() ) {
4783                                         $html = $msg->parseAsBlock();
4784                                         if ( trim( $html ) !== '' ) {
4785                                                 $notices[$editnotice_base] = Html::rawElement(
4786                                                         'div',
4787                                                         [ 'class' => [
4788                                                                 'mw-editnotice',
4789                                                                 'mw-editnotice-base',
4790                                                                 Sanitizer::escapeClass( "mw-$editnotice_base" )
4791                                                         ] ],
4792                                                         $html
4793                                                 );
4794                                         }
4795                                 }
4796                         }
4797                 } else {
4798                         // Even if there are no subpages in namespace, we still don't want "/" in MediaWiki message keys
4799                         $editnoticeText = $editnotice_ns . '-' . strtr( $this->getDBkey(), '/', '-' );
4800                         $msg = wfMessage( $editnoticeText );
4801                         if ( $msg->exists() ) {
4802                                 $html = $msg->parseAsBlock();
4803                                 if ( trim( $html ) !== '' ) {
4804                                         $notices[$editnoticeText] = Html::rawElement(
4805                                                 'div',
4806                                                 [ 'class' => [
4807                                                         'mw-editnotice',
4808                                                         'mw-editnotice-page',
4809                                                         Sanitizer::escapeClass( "mw-$editnoticeText" )
4810                                                 ] ],
4811                                                 $html
4812                                         );
4813                                 }
4814                         }
4815                 }
4816
4817                 Hooks::run( 'TitleGetEditNotices', [ $this, $oldid, &$notices ] );
4818                 return $notices;
4819         }
4820
4821         /**
4822          * @return array
4823          */
4824         public function __sleep() {
4825                 return [
4826                         'mNamespace',
4827                         'mDbkeyform',
4828                         'mFragment',
4829                         'mInterwiki',
4830                         'mLocalInterwiki',
4831                         'mUserCaseDBKey',
4832                         'mDefaultNamespace',
4833                 ];
4834         }
4835
4836         public function __wakeup() {
4837                 $this->mArticleID = ( $this->mNamespace >= 0 ) ? -1 : 0;
4838                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
4839                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
4840         }
4841
4842 }