includes/Title.php

   1 <?php
   2 /**
   3  * Representation of a title within %MediaWiki.
   4  *
   5  * See title.txt
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License along
  18  * with this program; if not, write to the Free Software Foundation, Inc.,
  19  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  20  * http://www.gnu.org/copyleft/gpl.html
  21  *
  22  * @file
  23  */
  24
  25 use Wikimedia\Rdbms\IDatabase;
  26 use MediaWiki\Linker\LinkTarget;
  27 use MediaWiki\Interwiki\InterwikiLookup;
  28 use MediaWiki\MediaWikiServices;
  29
  30 /**
  31  * Represents a title within MediaWiki.
  32  * Optionally may contain an interwiki designation or namespace.
  33  * @note This class can fetch various kinds of data from the database;
  34  *       however, it does so inefficiently.
  35  * @note Consider using a TitleValue object instead. TitleValue is more lightweight
  36  *       and does not rely on global state or the database.
  37  */
  38 class Title implements LinkTarget {
  39         /** @var HashBagOStuff */
  40         static private $titleCache = null;
  41
  42         /**
  43          * Title::newFromText maintains a cache to avoid expensive re-normalization of
  44          * commonly used titles. On a batch operation this can become a memory leak
  45          * if not bounded. After hitting this many titles reset the cache.
  46          */
  47         const CACHE_MAX = 1000;
  48
  49         /**
  50          * Used to be GAID_FOR_UPDATE define. Used with getArticleID() and friends
  51          * to use the master DB
  52          */
  53         const GAID_FOR_UPDATE = 1;
  54
  55         /**
  56          * @name Private member variables
  57          * Please use the accessor functions instead.
  58          * @private
  59          */
  60         // @{
  61
  62         /** @var string Text form (spaces not underscores) of the main part */
  63         public $mTextform = '';
  64
  65         /** @var string URL-encoded form of the main part */
  66         public $mUrlform = '';
  67
  68         /** @var string Main part with underscores */
  69         public $mDbkeyform = '';
  70
  71         /** @var string Database key with the initial letter in the case specified by the user */
  72         protected $mUserCaseDBKey;
  73
  74         /** @var int Namespace index, i.e. one of the NS_xxxx constants */
  75         public $mNamespace = NS_MAIN;
  76
  77         /** @var string Interwiki prefix */
  78         public $mInterwiki = '';
  79
  80         /** @var bool Was this Title created from a string with a local interwiki prefix? */
  81         private $mLocalInterwiki = false;
  82
  83         /** @var string Title fragment (i.e. the bit after the #) */
  84         public $mFragment = '';
  85
  86         /** @var int Article ID, fetched from the link cache on demand */
  87         public $mArticleID = -1;
  88
  89         /** @var bool|int ID of most recent revision */
  90         protected $mLatestID = false;
  91
  92         /**
  93          * @var bool|string ID of the page's content model, i.e. one of the
  94          *   CONTENT_MODEL_XXX constants
  95          */
  96         private $mContentModel = false;
  97
  98         /**
  99          * @var bool If a content model was forced via setContentModel()
 100          *   this will be true to avoid having other code paths reset it
 101          */
 102         private $mForcedContentModel = false;
 103
 104         /** @var int Estimated number of revisions; null of not loaded */
 105         private $mEstimateRevisions;
 106
 107         /** @var array Array of groups allowed to edit this article */
 108         public $mRestrictions = [];
 109
 110         /** @var string|bool */
 111         protected $mOldRestrictions = false;
 112
 113         /** @var bool Cascade restrictions on this page to included templates and images? */
 114         public $mCascadeRestriction;
 115
 116         /** Caching the results of getCascadeProtectionSources */
 117         public $mCascadingRestrictions;
 118
 119         /** @var array When do the restrictions on this page expire? */
 120         protected $mRestrictionsExpiry = [];
 121
 122         /** @var bool Are cascading restrictions in effect on this page? */
 123         protected $mHasCascadingRestrictions;
 124
 125         /** @var array Where are the cascading restrictions coming from on this page? */
 126         public $mCascadeSources;
 127
 128         /** @var bool Boolean for initialisation on demand */
 129         public $mRestrictionsLoaded = false;
 130
 131         /** @var string Text form including namespace/interwiki, initialised on demand */
 132         protected $mPrefixedText = null;
 133
 134         /** @var mixed Cached value for getTitleProtection (create protection) */
 135         public $mTitleProtection;
 136
 137         /**
 138          * @var int Namespace index when there is no namespace. Don't change the
 139          *   following default, NS_MAIN is hardcoded in several places. See T2696.
 140          *   Zero except in {{transclusion}} tags.
 141          */
 142         public $mDefaultNamespace = NS_MAIN;
 143
 144         /** @var int The page length, 0 for special pages */
 145         protected $mLength = -1;
 146
 147         /** @var null Is the article at this title a redirect? */
 148         public $mRedirect = null;
 149
 150         /** @var array Associative array of user ID -> timestamp/false */
 151         private $mNotificationTimestamp = [];
 152
 153         /** @var bool Whether a page has any subpages */
 154         private $mHasSubpages;
 155
 156         /** @var bool The (string) language code of the page's language and content code. */
 157         private $mPageLanguage = false;
 158
 159         /** @var string|bool|null The page language code from the database, null if not saved in
 160          * the database or false if not loaded, yet. */
 161         private $mDbPageLanguage = false;
 162
 163         /** @var TitleValue A corresponding TitleValue object */
 164         private $mTitleValue = null;
 165
 166         /** @var bool Would deleting this page be a big deletion? */
 167         private $mIsBigDeletion = null;
 168         // @}
 169
 170         /**
 171          * B/C kludge: provide a TitleParser for use by Title.
 172          * Ideally, Title would have no methods that need this.
 173          * Avoid usage of this singleton by using TitleValue
 174          * and the associated services when possible.
 175          *
 176          * @return TitleFormatter
 177          */
 178         private static function getTitleFormatter() {
 179                 return MediaWikiServices::getInstance()->getTitleFormatter();
 180         }
 181
 182         /**
 183          * B/C kludge: provide an InterwikiLookup for use by Title.
 184          * Ideally, Title would have no methods that need this.
 185          * Avoid usage of this singleton by using TitleValue
 186          * and the associated services when possible.
 187          *
 188          * @return InterwikiLookup
 189          */
 190         private static function getInterwikiLookup() {
 191                 return MediaWikiServices::getInstance()->getInterwikiLookup();
 192         }
 193
 194         /**
 195          * @access protected
 196          */
 197         function __construct() {
 198         }
 199
 200         /**
 201          * Create a new Title from a prefixed DB key
 202          *
 203          * @param string $key The database key, which has underscores
 204          *      instead of spaces, possibly including namespace and
 205          *      interwiki prefixes
 206          * @return Title|null Title, or null on an error
 207          */
 208         public static function newFromDBkey( $key ) {
 209                 $t = new Title();
 210                 $t->mDbkeyform = $key;
 211
 212                 try {
 213                         $t->secureAndSplit();
 214                         return $t;
 215                 } catch ( MalformedTitleException $ex ) {
 216                         return null;
 217                 }
 218         }
 219
 220         /**
 221          * Create a new Title from a TitleValue
 222          *
 223          * @param TitleValue $titleValue Assumed to be safe.
 224          *
 225          * @return Title
 226          */
 227         public static function newFromTitleValue( TitleValue $titleValue ) {
 228                 return self::newFromLinkTarget( $titleValue );
 229         }
 230
 231         /**
 232          * Create a new Title from a LinkTarget
 233          *
 234          * @param LinkTarget $linkTarget Assumed to be safe.
 235          *
 236          * @return Title
 237          */
 238         public static function newFromLinkTarget( LinkTarget $linkTarget ) {
 239                 if ( $linkTarget instanceof Title ) {
 240                         // Special case if it's already a Title object
 241                         return $linkTarget;
 242                 }
 243                 return self::makeTitle(
 244                         $linkTarget->getNamespace(),
 245                         $linkTarget->getText(),
 246                         $linkTarget->getFragment(),
 247                         $linkTarget->getInterwiki()
 248                 );
 249         }
 250
 251         /**
 252          * Create a new Title from text, such as what one would find in a link. De-
 253          * codes any HTML entities in the text.
 254          *
 255          * @param string|int|null $text The link text; spaces, prefixes, and an
 256          *   initial ':' indicating the main namespace are accepted.
 257          * @param int $defaultNamespace The namespace to use if none is specified
 258          *   by a prefix.  If you want to force a specific namespace even if
 259          *   $text might begin with a namespace prefix, use makeTitle() or
 260          *   makeTitleSafe().
 261          * @throws InvalidArgumentException
 262          * @return Title|null Title or null on an error.
 263          */
 264         public static function newFromText( $text, $defaultNamespace = NS_MAIN ) {
 265                 // DWIM: Integers can be passed in here when page titles are used as array keys.
 266                 if ( $text !== null && !is_string( $text ) && !is_int( $text ) ) {
 267                         throw new InvalidArgumentException( '$text must be a string.' );
 268                 }
 269                 if ( $text === null ) {
 270                         return null;
 271                 }
 272
 273                 try {
 274                         return Title::newFromTextThrow( strval( $text ), $defaultNamespace );
 275                 } catch ( MalformedTitleException $ex ) {
 276                         return null;
 277                 }
 278         }
 279
 280         /**
 281          * Like Title::newFromText(), but throws MalformedTitleException when the title is invalid,
 282          * rather than returning null.
 283          *
 284          * The exception subclasses encode detailed information about why the title is invalid.
 285          *
 286          * @see Title::newFromText
 287          *
 288          * @since 1.25
 289          * @param string $text Title text to check
 290          * @param int $defaultNamespace
 291          * @throws MalformedTitleException If the title is invalid
 292          * @return Title
 293          */
 294         public static function newFromTextThrow( $text, $defaultNamespace = NS_MAIN ) {
 295                 if ( is_object( $text ) ) {
 296                         throw new MWException( '$text must be a string, given an object' );
 297                 }
 298
 299                 $titleCache = self::getTitleCache();
 300
 301                 // Wiki pages often contain multiple links to the same page.
 302                 // Title normalization and parsing can become expensive on pages with many
 303                 // links, so we can save a little time by caching them.
 304                 // In theory these are value objects and won't get changed...
 305                 if ( $defaultNamespace == NS_MAIN ) {
 306                         $t = $titleCache->get( $text );
 307                         if ( $t ) {
 308                                 return $t;
 309                         }
 310                 }
 311
 312                 // Convert things like &eacute; &#257; or &#x3017; into normalized (T16952) text
 313                 $filteredText = Sanitizer::decodeCharReferencesAndNormalize( $text );
 314
 315                 $t = new Title();
 316                 $t->mDbkeyform = strtr( $filteredText, ' ', '_' );
 317                 $t->mDefaultNamespace = intval( $defaultNamespace );
 318
 319                 $t->secureAndSplit();
 320                 if ( $defaultNamespace == NS_MAIN ) {
 321                         $titleCache->set( $text, $t );
 322                 }
 323                 return $t;
 324         }
 325
 326         /**
 327          * THIS IS NOT THE FUNCTION YOU WANT. Use Title::newFromText().
 328          *
 329          * Example of wrong and broken code:
 330          * $title = Title::newFromURL( $wgRequest->getVal( 'title' ) );
 331          *
 332          * Example of right code:
 333          * $title = Title::newFromText( $wgRequest->getVal( 'title' ) );
 334          *
 335          * Create a new Title from URL-encoded text. Ensures that
 336          * the given title's length does not exceed the maximum.
 337          *
 338          * @param string $url The title, as might be taken from a URL
 339          * @return Title|null The new object, or null on an error
 340          */
 341         public static function newFromURL( $url ) {
 342                 $t = new Title();
 343
 344                 # For compatibility with old buggy URLs. "+" is usually not valid in titles,
 345                 # but some URLs used it as a space replacement and they still come
 346                 # from some external search tools.
 347                 if ( strpos( self::legalChars(), '+' ) === false ) {
 348                         $url = strtr( $url, '+', ' ' );
 349                 }
 350
 351                 $t->mDbkeyform = strtr( $url, ' ', '_' );
 352
 353                 try {
 354                         $t->secureAndSplit();
 355                         return $t;
 356                 } catch ( MalformedTitleException $ex ) {
 357                         return null;
 358                 }
 359         }
 360
 361         /**
 362          * @return HashBagOStuff
 363          */
 364         private static function getTitleCache() {
 365                 if ( self::$titleCache == null ) {
 366                         self::$titleCache = new HashBagOStuff( [ 'maxKeys' => self::CACHE_MAX ] );
 367                 }
 368                 return self::$titleCache;
 369         }
 370
 371         /**
 372          * Returns a list of fields that are to be selected for initializing Title
 373          * objects or LinkCache entries. Uses $wgContentHandlerUseDB to determine
 374          * whether to include page_content_model.
 375          *
 376          * @return array
 377          */
 378         protected static function getSelectFields() {
 379                 global $wgContentHandlerUseDB, $wgPageLanguageUseDB;
 380
 381                 $fields = [
 382                         'page_namespace', 'page_title', 'page_id',
 383                         'page_len', 'page_is_redirect', 'page_latest',
 384                 ];
 385
 386                 if ( $wgContentHandlerUseDB ) {
 387                         $fields[] = 'page_content_model';
 388                 }
 389
 390                 if ( $wgPageLanguageUseDB ) {
 391                         $fields[] = 'page_lang';
 392                 }
 393
 394                 return $fields;
 395         }
 396
 397         /**
 398          * Create a new Title from an article ID
 399          *
 400          * @param int $id The page_id corresponding to the Title to create
 401          * @param int $flags Use Title::GAID_FOR_UPDATE to use master
 402          * @return Title|null The new object, or null on an error
 403          */
 404         public static function newFromID( $id, $flags = 0 ) {
 405                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_REPLICA );
 406                 $row = $db->selectRow(
 407                         'page',
 408                         self::getSelectFields(),
 409                         [ 'page_id' => $id ],
 410                         __METHOD__
 411                 );
 412                 if ( $row !== false ) {
 413                         $title = Title::newFromRow( $row );
 414                 } else {
 415                         $title = null;
 416                 }
 417                 return $title;
 418         }
 419
 420         /**
 421          * Make an array of titles from an array of IDs
 422          *
 423          * @param int[] $ids Array of IDs
 424          * @return Title[] Array of Titles
 425          */
 426         public static function newFromIDs( $ids ) {
 427                 if ( !count( $ids ) ) {
 428                         return [];
 429                 }
 430                 $dbr = wfGetDB( DB_REPLICA );
 431
 432                 $res = $dbr->select(
 433                         'page',
 434                         self::getSelectFields(),
 435                         [ 'page_id' => $ids ],
 436                         __METHOD__
 437                 );
 438
 439                 $titles = [];
 440                 foreach ( $res as $row ) {
 441                         $titles[] = Title::newFromRow( $row );
 442                 }
 443                 return $titles;
 444         }
 445
 446         /**
 447          * Make a Title object from a DB row
 448          *
 449          * @param stdClass $row Object database row (needs at least page_title,page_namespace)
 450          * @return Title Corresponding Title
 451          */
 452         public static function newFromRow( $row ) {
 453                 $t = self::makeTitle( $row->page_namespace, $row->page_title );
 454                 $t->loadFromRow( $row );
 455                 return $t;
 456         }
 457
 458         /**
 459          * Load Title object fields from a DB row.
 460          * If false is given, the title will be treated as non-existing.
 461          *
 462          * @param stdClass|bool $row Database row
 463          */
 464         public function loadFromRow( $row ) {
 465                 if ( $row ) { // page found
 466                         if ( isset( $row->page_id ) ) {
 467                                 $this->mArticleID = (int)$row->page_id;
 468                         }
 469                         if ( isset( $row->page_len ) ) {
 470                                 $this->mLength = (int)$row->page_len;
 471                         }
 472                         if ( isset( $row->page_is_redirect ) ) {
 473                                 $this->mRedirect = (bool)$row->page_is_redirect;
 474                         }
 475                         if ( isset( $row->page_latest ) ) {
 476                                 $this->mLatestID = (int)$row->page_latest;
 477                         }
 478                         if ( !$this->mForcedContentModel && isset( $row->page_content_model ) ) {
 479                                 $this->mContentModel = strval( $row->page_content_model );
 480                         } elseif ( !$this->mForcedContentModel ) {
 481                                 $this->mContentModel = false; # initialized lazily in getContentModel()
 482                         }
 483                         if ( isset( $row->page_lang ) ) {
 484                                 $this->mDbPageLanguage = (string)$row->page_lang;
 485                         }
 486                         if ( isset( $row->page_restrictions ) ) {
 487                                 $this->mOldRestrictions = $row->page_restrictions;
 488                         }
 489                 } else { // page not found
 490                         $this->mArticleID = 0;
 491                         $this->mLength = 0;
 492                         $this->mRedirect = false;
 493                         $this->mLatestID = 0;
 494                         if ( !$this->mForcedContentModel ) {
 495                                 $this->mContentModel = false; # initialized lazily in getContentModel()
 496                         }
 497                 }
 498         }
 499
 500         /**
 501          * Create a new Title from a namespace index and a DB key.
 502          * It's assumed that $ns and $title are *valid*, for instance when
 503          * they came directly from the database or a special page name.
 504          * For convenience, spaces are converted to underscores so that
 505          * eg user_text fields can be used directly.
 506          *
 507          * @param int $ns The namespace of the article
 508          * @param string $title The unprefixed database key form
 509          * @param string $fragment The link fragment (after the "#")
 510          * @param string $interwiki The interwiki prefix
 511          * @return Title The new object
 512          */
 513         public static function makeTitle( $ns, $title, $fragment = '', $interwiki = '' ) {
 514                 $t = new Title();
 515                 $t->mInterwiki = $interwiki;
 516                 $t->mFragment = $fragment;
 517                 $t->mNamespace = $ns = intval( $ns );
 518                 $t->mDbkeyform = strtr( $title, ' ', '_' );
 519                 $t->mArticleID = ( $ns >= 0 ) ? -1 : 0;
 520                 $t->mUrlform = wfUrlencode( $t->mDbkeyform );
 521                 $t->mTextform = strtr( $title, '_', ' ' );
 522                 $t->mContentModel = false; # initialized lazily in getContentModel()
 523                 return $t;
 524         }
 525
 526         /**
 527          * Create a new Title from a namespace index and a DB key.
 528          * The parameters will be checked for validity, which is a bit slower
 529          * than makeTitle() but safer for user-provided data.
 530          *
 531          * @param int $ns The namespace of the article
 532          * @param string $title Database key form
 533          * @param string $fragment The link fragment (after the "#")
 534          * @param string $interwiki Interwiki prefix
 535          * @return Title|null The new object, or null on an error
 536          */
 537         public static function makeTitleSafe( $ns, $title, $fragment = '', $interwiki = '' ) {
 538                 if ( !MWNamespace::exists( $ns ) ) {
 539                         return null;
 540                 }
 541
 542                 $t = new Title();
 543                 $t->mDbkeyform = Title::makeName( $ns, $title, $fragment, $interwiki, true );
 544
 545                 try {
 546                         $t->secureAndSplit();
 547                         return $t;
 548                 } catch ( MalformedTitleException $ex ) {
 549                         return null;
 550                 }
 551         }
 552
 553         /**
 554          * Create a new Title for the Main Page
 555          *
 556          * @return Title The new object
 557          */
 558         public static function newMainPage() {
 559                 $title = Title::newFromText( wfMessage( 'mainpage' )->inContentLanguage()->text() );
 560                 // Don't give fatal errors if the message is broken
 561                 if ( !$title ) {
 562                         $title = Title::newFromText( 'Main Page' );
 563                 }
 564                 return $title;
 565         }
 566
 567         /**
 568          * Get the prefixed DB key associated with an ID
 569          *
 570          * @param int $id The page_id of the article
 571          * @return Title|null An object representing the article, or null if no such article was found
 572          */
 573         public static function nameOf( $id ) {
 574                 $dbr = wfGetDB( DB_REPLICA );
 575
 576                 $s = $dbr->selectRow(
 577                         'page',
 578                         [ 'page_namespace', 'page_title' ],
 579                         [ 'page_id' => $id ],
 580                         __METHOD__
 581                 );
 582                 if ( $s === false ) {
 583                         return null;
 584                 }
 585
 586                 $n = self::makeName( $s->page_namespace, $s->page_title );
 587                 return $n;
 588         }
 589
 590         /**
 591          * Get a regex character class describing the legal characters in a link
 592          *
 593          * @return string The list of characters, not delimited
 594          */
 595         public static function legalChars() {
 596                 global $wgLegalTitleChars;
 597                 return $wgLegalTitleChars;
 598         }
 599
 600         /**
 601          * Returns a simple regex that will match on characters and sequences invalid in titles.
 602          * Note that this doesn't pick up many things that could be wrong with titles, but that
 603          * replacing this regex with something valid will make many titles valid.
 604          *
 605          * @deprecated since 1.25, use MediaWikiTitleCodec::getTitleInvalidRegex() instead
 606          *
 607          * @return string Regex string
 608          */
 609         static function getTitleInvalidRegex() {
 610                 wfDeprecated( __METHOD__, '1.25' );
 611                 return MediaWikiTitleCodec::getTitleInvalidRegex();
 612         }
 613
 614         /**
 615          * Utility method for converting a character sequence from bytes to Unicode.
 616          *
 617          * Primary usecase being converting $wgLegalTitleChars to a sequence usable in
 618          * javascript, as PHP uses UTF-8 bytes where javascript uses Unicode code units.
 619          *
 620          * @param string $byteClass
 621          * @return string
 622          */
 623         public static function convertByteClassToUnicodeClass( $byteClass ) {
 624                 $length = strlen( $byteClass );
 625                 // Input token queue
 626                 $x0 = $x1 = $x2 = '';
 627                 // Decoded queue
 628                 $d0 = $d1 = $d2 = '';
 629                 // Decoded integer codepoints
 630                 $ord0 = $ord1 = $ord2 = 0;
 631                 // Re-encoded queue
 632                 $r0 = $r1 = $r2 = '';
 633                 // Output
 634                 $out = '';
 635                 // Flags
 636                 $allowUnicode = false;
 637                 for ( $pos = 0; $pos < $length; $pos++ ) {
 638                         // Shift the queues down
 639                         $x2 = $x1;
 640                         $x1 = $x0;
 641                         $d2 = $d1;
 642                         $d1 = $d0;
 643                         $ord2 = $ord1;
 644                         $ord1 = $ord0;
 645                         $r2 = $r1;
 646                         $r1 = $r0;
 647                         // Load the current input token and decoded values
 648                         $inChar = $byteClass[$pos];
 649                         if ( $inChar == '\\' ) {
 650                                 if ( preg_match( '/x([0-9a-fA-F]{2})/A', $byteClass, $m, 0, $pos + 1 ) ) {
 651                                         $x0 = $inChar . $m[0];
 652                                         $d0 = chr( hexdec( $m[1] ) );
 653                                         $pos += strlen( $m[0] );
 654                                 } elseif ( preg_match( '/[0-7]{3}/A', $byteClass, $m, 0, $pos + 1 ) ) {
 655                                         $x0 = $inChar . $m[0];
 656                                         $d0 = chr( octdec( $m[0] ) );
 657                                         $pos += strlen( $m[0] );
 658                                 } elseif ( $pos + 1 >= $length ) {
 659                                         $x0 = $d0 = '\\';
 660                                 } else {
 661                                         $d0 = $byteClass[$pos + 1];
 662                                         $x0 = $inChar . $d0;
 663                                         $pos += 1;
 664                                 }
 665                         } else {
 666                                 $x0 = $d0 = $inChar;
 667                         }
 668                         $ord0 = ord( $d0 );
 669                         // Load the current re-encoded value
 670                         if ( $ord0 < 32 || $ord0 == 0x7f ) {
 671                                 $r0 = sprintf( '\x%02x', $ord0 );
 672                         } elseif ( $ord0 >= 0x80 ) {
 673                                 // Allow unicode if a single high-bit character appears
 674                                 $r0 = sprintf( '\x%02x', $ord0 );
 675                                 $allowUnicode = true;
 676                         } elseif ( strpos( '-\\[]^', $d0 ) !== false ) {
 677                                 $r0 = '\\' . $d0;
 678                         } else {
 679                                 $r0 = $d0;
 680                         }
 681                         // Do the output
 682                         if ( $x0 !== '' && $x1 === '-' && $x2 !== '' ) {
 683                                 // Range
 684                                 if ( $ord2 > $ord0 ) {
 685                                         // Empty range
 686                                 } elseif ( $ord0 >= 0x80 ) {
 687                                         // Unicode range
 688                                         $allowUnicode = true;
 689                                         if ( $ord2 < 0x80 ) {
 690                                                 // Keep the non-unicode section of the range
 691                                                 $out .= "$r2-\\x7F";
 692                                         }
 693                                 } else {
 694                                         // Normal range
 695                                         $out .= "$r2-$r0";
 696                                 }
 697                                 // Reset state to the initial value
 698                                 $x0 = $x1 = $d0 = $d1 = $r0 = $r1 = '';
 699                         } elseif ( $ord2 < 0x80 ) {
 700                                 // ASCII character
 701                                 $out .= $r2;
 702                         }
 703                 }
 704                 if ( $ord1 < 0x80 ) {
 705                         $out .= $r1;
 706                 }
 707                 if ( $ord0 < 0x80 ) {
 708                         $out .= $r0;
 709                 }
 710                 if ( $allowUnicode ) {
 711                         $out .= '\u0080-\uFFFF';
 712                 }
 713                 return $out;
 714         }
 715
 716         /**
 717          * Make a prefixed DB key from a DB key and a namespace index
 718          *
 719          * @param int $ns Numerical representation of the namespace
 720          * @param string $title The DB key form the title
 721          * @param string $fragment The link fragment (after the "#")
 722          * @param string $interwiki The interwiki prefix
 723          * @param bool $canonicalNamespace If true, use the canonical name for
 724          *   $ns instead of the localized version.
 725          * @return string The prefixed form of the title
 726          */
 727         public static function makeName( $ns, $title, $fragment = '', $interwiki = '',
 728                 $canonicalNamespace = false
 729         ) {
 730                 global $wgContLang;
 731
 732                 if ( $canonicalNamespace ) {
 733                         $namespace = MWNamespace::getCanonicalName( $ns );
 734                 } else {
 735                         $namespace = $wgContLang->getNsText( $ns );
 736                 }
 737                 $name = $namespace == '' ? $title : "$namespace:$title";
 738                 if ( strval( $interwiki ) != '' ) {
 739                         $name = "$interwiki:$name";
 740                 }
 741                 if ( strval( $fragment ) != '' ) {
 742                         $name .= '#' . $fragment;
 743                 }
 744                 return $name;
 745         }
 746
 747         /**
 748          * Escape a text fragment, say from a link, for a URL
 749          *
 750          * @param string $fragment Containing a URL or link fragment (after the "#")
 751          * @return string Escaped string
 752          */
 753         static function escapeFragmentForURL( $fragment ) {
 754                 # Note that we don't urlencode the fragment.  urlencoded Unicode
 755                 # fragments appear not to work in IE (at least up to 7) or in at least
 756                 # one version of Opera 9.x.  The W3C validator, for one, doesn't seem
 757                 # to care if they aren't encoded.
 758                 return Sanitizer::escapeId( $fragment, 'noninitial' );
 759         }
 760
 761         /**
 762          * Callback for usort() to do title sorts by (namespace, title)
 763          *
 764          * @param LinkTarget $a
 765          * @param LinkTarget $b
 766          *
 767          * @return int Result of string comparison, or namespace comparison
 768          */
 769         public static function compare( LinkTarget $a, LinkTarget $b ) {
 770                 if ( $a->getNamespace() == $b->getNamespace() ) {
 771                         return strcmp( $a->getText(), $b->getText() );
 772                 } else {
 773                         return $a->getNamespace() - $b->getNamespace();
 774                 }
 775         }
 776
 777         /**
 778          * Determine whether the object refers to a page within
 779          * this project (either this wiki or a wiki with a local
 780          * interwiki, see https://www.mediawiki.org/wiki/Manual:Interwiki_table#iw_local )
 781          *
 782          * @return bool True if this is an in-project interwiki link or a wikilink, false otherwise
 783          */
 784         public function isLocal() {
 785                 if ( $this->isExternal() ) {
 786                         $iw = self::getInterwikiLookup()->fetch( $this->mInterwiki );
 787                         if ( $iw ) {
 788                                 return $iw->isLocal();
 789                         }
 790                 }
 791                 return true;
 792         }
 793
 794         /**
 795          * Is this Title interwiki?
 796          *
 797          * @return bool
 798          */
 799         public function isExternal() {
 800                 return $this->mInterwiki !== '';
 801         }
 802
 803         /**
 804          * Get the interwiki prefix
 805          *
 806          * Use Title::isExternal to check if a interwiki is set
 807          *
 808          * @return string Interwiki prefix
 809          */
 810         public function getInterwiki() {
 811                 return $this->mInterwiki;
 812         }
 813
 814         /**
 815          * Was this a local interwiki link?
 816          *
 817          * @return bool
 818          */
 819         public function wasLocalInterwiki() {
 820                 return $this->mLocalInterwiki;
 821         }
 822
 823         /**
 824          * Determine whether the object refers to a page within
 825          * this project and is transcludable.
 826          *
 827          * @return bool True if this is transcludable
 828          */
 829         public function isTrans() {
 830                 if ( !$this->isExternal() ) {
 831                         return false;
 832                 }
 833
 834                 return self::getInterwikiLookup()->fetch( $this->mInterwiki )->isTranscludable();
 835         }
 836
 837         /**
 838          * Returns the DB name of the distant wiki which owns the object.
 839          *
 840          * @return string|false The DB name
 841          */
 842         public function getTransWikiID() {
 843                 if ( !$this->isExternal() ) {
 844                         return false;
 845                 }
 846
 847                 return self::getInterwikiLookup()->fetch( $this->mInterwiki )->getWikiID();
 848         }
 849
 850         /**
 851          * Get a TitleValue object representing this Title.
 852          *
 853          * @note Not all valid Titles have a corresponding valid TitleValue
 854          * (e.g. TitleValues cannot represent page-local links that have a
 855          * fragment but no title text).
 856          *
 857          * @return TitleValue|null
 858          */
 859         public function getTitleValue() {
 860                 if ( $this->mTitleValue === null ) {
 861                         try {
 862                                 $this->mTitleValue = new TitleValue(
 863                                         $this->getNamespace(),
 864                                         $this->getDBkey(),
 865                                         $this->getFragment(),
 866                                         $this->getInterwiki()
 867                                 );
 868                         } catch ( InvalidArgumentException $ex ) {
 869                                 wfDebug( __METHOD__ . ': Can\'t create a TitleValue for [[' .
 870                                         $this->getPrefixedText() . ']]: ' . $ex->getMessage() . "\n" );
 871                         }
 872                 }
 873
 874                 return $this->mTitleValue;
 875         }
 876
 877         /**
 878          * Get the text form (spaces not underscores) of the main part
 879          *
 880          * @return string Main part of the title
 881          */
 882         public function getText() {
 883                 return $this->mTextform;
 884         }
 885
 886         /**
 887          * Get the URL-encoded form of the main part
 888          *
 889          * @return string Main part of the title, URL-encoded
 890          */
 891         public function getPartialURL() {
 892                 return $this->mUrlform;
 893         }
 894
 895         /**
 896          * Get the main part with underscores
 897          *
 898          * @return string Main part of the title, with underscores
 899          */
 900         public function getDBkey() {
 901                 return $this->mDbkeyform;
 902         }
 903
 904         /**
 905          * Get the DB key with the initial letter case as specified by the user
 906          *
 907          * @return string DB key
 908          */
 909         function getUserCaseDBKey() {
 910                 if ( !is_null( $this->mUserCaseDBKey ) ) {
 911                         return $this->mUserCaseDBKey;
 912                 } else {
 913                         // If created via makeTitle(), $this->mUserCaseDBKey is not set.
 914                         return $this->mDbkeyform;
 915                 }
 916         }
 917
 918         /**
 919          * Get the namespace index, i.e. one of the NS_xxxx constants.
 920          *
 921          * @return int Namespace index
 922          */
 923         public function getNamespace() {
 924                 return $this->mNamespace;
 925         }
 926
 927         /**
 928          * Get the page's content model id, see the CONTENT_MODEL_XXX constants.
 929          *
 930          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
 931          * @return string Content model id
 932          */
 933         public function getContentModel( $flags = 0 ) {
 934                 if ( !$this->mForcedContentModel
 935                         && ( !$this->mContentModel || $flags === Title::GAID_FOR_UPDATE )
 936                         && $this->getArticleID( $flags )
 937                 ) {
 938                         $linkCache = LinkCache::singleton();
 939                         $linkCache->addLinkObj( $this ); # in case we already had an article ID
 940                         $this->mContentModel = $linkCache->getGoodLinkFieldObj( $this, 'model' );
 941                 }
 942
 943                 if ( !$this->mContentModel ) {
 944                         $this->mContentModel = ContentHandler::getDefaultModelFor( $this );
 945                 }
 946
 947                 return $this->mContentModel;
 948         }
 949
 950         /**
 951          * Convenience method for checking a title's content model name
 952          *
 953          * @param string $id The content model ID (use the CONTENT_MODEL_XXX constants).
 954          * @return bool True if $this->getContentModel() == $id
 955          */
 956         public function hasContentModel( $id ) {
 957                 return $this->getContentModel() == $id;
 958         }
 959
 960         /**
 961          * Set a proposed content model for the page for permissions
 962          * checking. This does not actually change the content model
 963          * of a title!
 964          *
 965          * Additionally, you should make sure you've checked
 966          * ContentHandler::canBeUsedOn() first.
 967          *
 968          * @since 1.28
 969          * @param string $model CONTENT_MODEL_XXX constant
 970          */
 971         public function setContentModel( $model ) {
 972                 $this->mContentModel = $model;
 973                 $this->mForcedContentModel = true;
 974         }
 975
 976         /**
 977          * Get the namespace text
 978          *
 979          * @return string|false Namespace text
 980          */
 981         public function getNsText() {
 982                 if ( $this->isExternal() ) {
 983                         // This probably shouldn't even happen,
 984                         // but for interwiki transclusion it sometimes does.
 985                         // Use the canonical namespaces if possible to try to
 986                         // resolve a foreign namespace.
 987                         if ( MWNamespace::exists( $this->mNamespace ) ) {
 988                                 return MWNamespace::getCanonicalName( $this->mNamespace );
 989                         }
 990                 }
 991
 992                 try {
 993                         $formatter = self::getTitleFormatter();
 994                         return $formatter->getNamespaceName( $this->mNamespace, $this->mDbkeyform );
 995                 } catch ( InvalidArgumentException $ex ) {
 996                         wfDebug( __METHOD__ . ': ' . $ex->getMessage() . "\n" );
 997                         return false;
 998                 }
 999         }
1000
1001         /**
1002          * Get the namespace text of the subject (rather than talk) page
1003          *
1004          * @return string Namespace text
1005          */
1006         public function getSubjectNsText() {
1007                 global $wgContLang;
1008                 return $wgContLang->getNsText( MWNamespace::getSubject( $this->mNamespace ) );
1009         }
1010
1011         /**
1012          * Get the namespace text of the talk page
1013          *
1014          * @return string Namespace text
1015          */
1016         public function getTalkNsText() {
1017                 global $wgContLang;
1018                 return $wgContLang->getNsText( MWNamespace::getTalk( $this->mNamespace ) );
1019         }
1020
1021         /**
1022          * Could this title have a corresponding talk page?
1023          *
1024          * @return bool
1025          */
1026         public function canTalk() {
1027                 return MWNamespace::canTalk( $this->mNamespace );
1028         }
1029
1030         /**
1031          * Is this in a namespace that allows actual pages?
1032          *
1033          * @return bool
1034          */
1035         public function canExist() {
1036                 return $this->mNamespace >= NS_MAIN;
1037         }
1038
1039         /**
1040          * Can this title be added to a user's watchlist?
1041          *
1042          * @return bool
1043          */
1044         public function isWatchable() {
1045                 return !$this->isExternal() && MWNamespace::isWatchable( $this->getNamespace() );
1046         }
1047
1048         /**
1049          * Returns true if this is a special page.
1050          *
1051          * @return bool
1052          */
1053         public function isSpecialPage() {
1054                 return $this->getNamespace() == NS_SPECIAL;
1055         }
1056
1057         /**
1058          * Returns true if this title resolves to the named special page
1059          *
1060          * @param string $name The special page name
1061          * @return bool
1062          */
1063         public function isSpecial( $name ) {
1064                 if ( $this->isSpecialPage() ) {
1065                         list( $thisName, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $this->getDBkey() );
1066                         if ( $name == $thisName ) {
1067                                 return true;
1068                         }
1069                 }
1070                 return false;
1071         }
1072
1073         /**
1074          * If the Title refers to a special page alias which is not the local default, resolve
1075          * the alias, and localise the name as necessary.  Otherwise, return $this
1076          *
1077          * @return Title
1078          */
1079         public function fixSpecialName() {
1080                 if ( $this->isSpecialPage() ) {
1081                         list( $canonicalName, $par ) = SpecialPageFactory::resolveAlias( $this->mDbkeyform );
1082                         if ( $canonicalName ) {
1083                                 $localName = SpecialPageFactory::getLocalNameFor( $canonicalName, $par );
1084                                 if ( $localName != $this->mDbkeyform ) {
1085                                         return Title::makeTitle( NS_SPECIAL, $localName );
1086                                 }
1087                         }
1088                 }
1089                 return $this;
1090         }
1091
1092         /**
1093          * Returns true if the title is inside the specified namespace.
1094          *
1095          * Please make use of this instead of comparing to getNamespace()
1096          * This function is much more resistant to changes we may make
1097          * to namespaces than code that makes direct comparisons.
1098          * @param int $ns The namespace
1099          * @return bool
1100          * @since 1.19
1101          */
1102         public function inNamespace( $ns ) {
1103                 return MWNamespace::equals( $this->getNamespace(), $ns );
1104         }
1105
1106         /**
1107          * Returns true if the title is inside one of the specified namespaces.
1108          *
1109          * @param int|int[] $namespaces,... The namespaces to check for
1110          * @return bool
1111          * @since 1.19
1112          */
1113         public function inNamespaces( /* ... */ ) {
1114                 $namespaces = func_get_args();
1115                 if ( count( $namespaces ) > 0 && is_array( $namespaces[0] ) ) {
1116                         $namespaces = $namespaces[0];
1117                 }
1118
1119                 foreach ( $namespaces as $ns ) {
1120                         if ( $this->inNamespace( $ns ) ) {
1121                                 return true;
1122                         }
1123                 }
1124
1125                 return false;
1126         }
1127
1128         /**
1129          * Returns true if the title has the same subject namespace as the
1130          * namespace specified.
1131          * For example this method will take NS_USER and return true if namespace
1132          * is either NS_USER or NS_USER_TALK since both of them have NS_USER
1133          * as their subject namespace.
1134          *
1135          * This is MUCH simpler than individually testing for equivalence
1136          * against both NS_USER and NS_USER_TALK, and is also forward compatible.
1137          * @since 1.19
1138          * @param int $ns
1139          * @return bool
1140          */
1141         public function hasSubjectNamespace( $ns ) {
1142                 return MWNamespace::subjectEquals( $this->getNamespace(), $ns );
1143         }
1144
1145         /**
1146          * Is this Title in a namespace which contains content?
1147          * In other words, is this a content page, for the purposes of calculating
1148          * statistics, etc?
1149          *
1150          * @return bool
1151          */
1152         public function isContentPage() {
1153                 return MWNamespace::isContent( $this->getNamespace() );
1154         }
1155
1156         /**
1157          * Would anybody with sufficient privileges be able to move this page?
1158          * Some pages just aren't movable.
1159          *
1160          * @return bool
1161          */
1162         public function isMovable() {
1163                 if ( !MWNamespace::isMovable( $this->getNamespace() ) || $this->isExternal() ) {
1164                         // Interwiki title or immovable namespace. Hooks don't get to override here
1165                         return false;
1166                 }
1167
1168                 $result = true;
1169                 Hooks::run( 'TitleIsMovable', [ $this, &$result ] );
1170                 return $result;
1171         }
1172
1173         /**
1174          * Is this the mainpage?
1175          * @note Title::newFromText seems to be sufficiently optimized by the title
1176          * cache that we don't need to over-optimize by doing direct comparisons and
1177          * accidentally creating new bugs where $title->equals( Title::newFromText() )
1178          * ends up reporting something differently than $title->isMainPage();
1179          *
1180          * @since 1.18
1181          * @return bool
1182          */
1183         public function isMainPage() {
1184                 return $this->equals( Title::newMainPage() );
1185         }
1186
1187         /**
1188          * Is this a subpage?
1189          *
1190          * @return bool
1191          */
1192         public function isSubpage() {
1193                 return MWNamespace::hasSubpages( $this->mNamespace )
1194                         ? strpos( $this->getText(), '/' ) !== false
1195                         : false;
1196         }
1197
1198         /**
1199          * Is this a conversion table for the LanguageConverter?
1200          *
1201          * @return bool
1202          */
1203         public function isConversionTable() {
1204                 // @todo ConversionTable should become a separate content model.
1205
1206                 return $this->getNamespace() == NS_MEDIAWIKI &&
1207                         strpos( $this->getText(), 'Conversiontable/' ) === 0;
1208         }
1209
1210         /**
1211          * Does that page contain wikitext, or it is JS, CSS or whatever?
1212          *
1213          * @return bool
1214          */
1215         public function isWikitextPage() {
1216                 return $this->hasContentModel( CONTENT_MODEL_WIKITEXT );
1217         }
1218
1219         /**
1220          * Could this page contain custom CSS or JavaScript for the global UI.
1221          * This is generally true for pages in the MediaWiki namespace having CONTENT_MODEL_CSS
1222          * or CONTENT_MODEL_JAVASCRIPT.
1223          *
1224          * This method does *not* return true for per-user JS/CSS. Use isCssJsSubpage()
1225          * for that!
1226          *
1227          * Note that this method should not return true for pages that contain and
1228          * show "inactive" CSS or JS.
1229          *
1230          * @return bool
1231          * @todo FIXME: Rename to isSiteConfigPage() and remove deprecated hook
1232          */
1233         public function isCssOrJsPage() {
1234                 $isCssOrJsPage = NS_MEDIAWIKI == $this->mNamespace
1235                         && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1236                                 || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1237
1238                 return $isCssOrJsPage;
1239         }
1240
1241         /**
1242          * Is this a .css or .js subpage of a user page?
1243          * @return bool
1244          * @todo FIXME: Rename to isUserConfigPage()
1245          */
1246         public function isCssJsSubpage() {
1247                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1248                                 && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1249                                         || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) ) );
1250         }
1251
1252         /**
1253          * Trim down a .css or .js subpage title to get the corresponding skin name
1254          *
1255          * @return string Containing skin name from .css or .js subpage title
1256          */
1257         public function getSkinFromCssJsSubpage() {
1258                 $subpage = explode( '/', $this->mTextform );
1259                 $subpage = $subpage[count( $subpage ) - 1];
1260                 $lastdot = strrpos( $subpage, '.' );
1261                 if ( $lastdot === false ) {
1262                         return $subpage; # Never happens: only called for names ending in '.css' or '.js'
1263                 }
1264                 return substr( $subpage, 0, $lastdot );
1265         }
1266
1267         /**
1268          * Is this a .css subpage of a user page?
1269          *
1270          * @return bool
1271          */
1272         public function isCssSubpage() {
1273                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1274                         && $this->hasContentModel( CONTENT_MODEL_CSS ) );
1275         }
1276
1277         /**
1278          * Is this a .js subpage of a user page?
1279          *
1280          * @return bool
1281          */
1282         public function isJsSubpage() {
1283                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1284                         && $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1285         }
1286
1287         /**
1288          * Is this a talk page of some sort?
1289          *
1290          * @return bool
1291          */
1292         public function isTalkPage() {
1293                 return MWNamespace::isTalk( $this->getNamespace() );
1294         }
1295
1296         /**
1297          * Get a Title object associated with the talk page of this article
1298          *
1299          * @return Title The object for the talk page
1300          */
1301         public function getTalkPage() {
1302                 return Title::makeTitle( MWNamespace::getTalk( $this->getNamespace() ), $this->getDBkey() );
1303         }
1304
1305         /**
1306          * Get a title object associated with the subject page of this
1307          * talk page
1308          *
1309          * @return Title The object for the subject page
1310          */
1311         public function getSubjectPage() {
1312                 // Is this the same title?
1313                 $subjectNS = MWNamespace::getSubject( $this->getNamespace() );
1314                 if ( $this->getNamespace() == $subjectNS ) {
1315                         return $this;
1316                 }
1317                 return Title::makeTitle( $subjectNS, $this->getDBkey() );
1318         }
1319
1320         /**
1321          * Get the other title for this page, if this is a subject page
1322          * get the talk page, if it is a subject page get the talk page
1323          *
1324          * @since 1.25
1325          * @throws MWException
1326          * @return Title
1327          */
1328         public function getOtherPage() {
1329                 if ( $this->isSpecialPage() ) {
1330                         throw new MWException( 'Special pages cannot have other pages' );
1331                 }
1332                 if ( $this->isTalkPage() ) {
1333                         return $this->getSubjectPage();
1334                 } else {
1335                         return $this->getTalkPage();
1336                 }
1337         }
1338
1339         /**
1340          * Get the default namespace index, for when there is no namespace
1341          *
1342          * @return int Default namespace index
1343          */
1344         public function getDefaultNamespace() {
1345                 return $this->mDefaultNamespace;
1346         }
1347
1348         /**
1349          * Get the Title fragment (i.e.\ the bit after the #) in text form
1350          *
1351          * Use Title::hasFragment to check for a fragment
1352          *
1353          * @return string Title fragment
1354          */
1355         public function getFragment() {
1356                 return $this->mFragment;
1357         }
1358
1359         /**
1360          * Check if a Title fragment is set
1361          *
1362          * @return bool
1363          * @since 1.23
1364          */
1365         public function hasFragment() {
1366                 return $this->mFragment !== '';
1367         }
1368
1369         /**
1370          * Get the fragment in URL form, including the "#" character if there is one
1371          * @return string Fragment in URL form
1372          */
1373         public function getFragmentForURL() {
1374                 if ( !$this->hasFragment() ) {
1375                         return '';
1376                 } else {
1377                         return '#' . Title::escapeFragmentForURL( $this->getFragment() );
1378                 }
1379         }
1380
1381         /**
1382          * Set the fragment for this title. Removes the first character from the
1383          * specified fragment before setting, so it assumes you're passing it with
1384          * an initial "#".
1385          *
1386          * Deprecated for public use, use Title::makeTitle() with fragment parameter,
1387          * or Title::createFragmentTarget().
1388          * Still in active use privately.
1389          *
1390          * @private
1391          * @param string $fragment Text
1392          */
1393         public function setFragment( $fragment ) {
1394                 $this->mFragment = strtr( substr( $fragment, 1 ), '_', ' ' );
1395         }
1396
1397         /**
1398          * Creates a new Title for a different fragment of the same page.
1399          *
1400          * @since 1.27
1401          * @param string $fragment
1402          * @return Title
1403          */
1404         public function createFragmentTarget( $fragment ) {
1405                 return self::makeTitle(
1406                         $this->getNamespace(),
1407                         $this->getText(),
1408                         $fragment,
1409                         $this->getInterwiki()
1410                 );
1411         }
1412
1413         /**
1414          * Prefix some arbitrary text with the namespace or interwiki prefix
1415          * of this object
1416          *
1417          * @param string $name The text
1418          * @return string The prefixed text
1419          */
1420         private function prefix( $name ) {
1421                 $p = '';
1422                 if ( $this->isExternal() ) {
1423                         $p = $this->mInterwiki . ':';
1424                 }
1425
1426                 if ( 0 != $this->mNamespace ) {
1427                         $p .= $this->getNsText() . ':';
1428                 }
1429                 return $p . $name;
1430         }
1431
1432         /**
1433          * Get the prefixed database key form
1434          *
1435          * @return string The prefixed title, with underscores and
1436          *  any interwiki and namespace prefixes
1437          */
1438         public function getPrefixedDBkey() {
1439                 $s = $this->prefix( $this->mDbkeyform );
1440                 $s = strtr( $s, ' ', '_' );
1441                 return $s;
1442         }
1443
1444         /**
1445          * Get the prefixed title with spaces.
1446          * This is the form usually used for display
1447          *
1448          * @return string The prefixed title, with spaces
1449          */
1450         public function getPrefixedText() {
1451                 if ( $this->mPrefixedText === null ) {
1452                         $s = $this->prefix( $this->mTextform );
1453                         $s = strtr( $s, '_', ' ' );
1454                         $this->mPrefixedText = $s;
1455                 }
1456                 return $this->mPrefixedText;
1457         }
1458
1459         /**
1460          * Return a string representation of this title
1461          *
1462          * @return string Representation of this title
1463          */
1464         public function __toString() {
1465                 return $this->getPrefixedText();
1466         }
1467
1468         /**
1469          * Get the prefixed title with spaces, plus any fragment
1470          * (part beginning with '#')
1471          *
1472          * @return string The prefixed title, with spaces and the fragment, including '#'
1473          */
1474         public function getFullText() {
1475                 $text = $this->getPrefixedText();
1476                 if ( $this->hasFragment() ) {
1477                         $text .= '#' . $this->getFragment();
1478                 }
1479                 return $text;
1480         }
1481
1482         /**
1483          * Get the root page name text without a namespace, i.e. the leftmost part before any slashes
1484          *
1485          * @par Example:
1486          * @code
1487          * Title::newFromText('User:Foo/Bar/Baz')->getRootText();
1488          * # returns: 'Foo'
1489          * @endcode
1490          *
1491          * @return string Root name
1492          * @since 1.20
1493          */
1494         public function getRootText() {
1495                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1496                         return $this->getText();
1497                 }
1498
1499                 return strtok( $this->getText(), '/' );
1500         }
1501
1502         /**
1503          * Get the root page name title, i.e. the leftmost part before any slashes
1504          *
1505          * @par Example:
1506          * @code
1507          * Title::newFromText('User:Foo/Bar/Baz')->getRootTitle();
1508          * # returns: Title{User:Foo}
1509          * @endcode
1510          *
1511          * @return Title Root title
1512          * @since 1.20
1513          */
1514         public function getRootTitle() {
1515                 return Title::makeTitle( $this->getNamespace(), $this->getRootText() );
1516         }
1517
1518         /**
1519          * Get the base page name without a namespace, i.e. the part before the subpage name
1520          *
1521          * @par Example:
1522          * @code
1523          * Title::newFromText('User:Foo/Bar/Baz')->getBaseText();
1524          * # returns: 'Foo/Bar'
1525          * @endcode
1526          *
1527          * @return string Base name
1528          */
1529         public function getBaseText() {
1530                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1531                         return $this->getText();
1532                 }
1533
1534                 $parts = explode( '/', $this->getText() );
1535                 # Don't discard the real title if there's no subpage involved
1536                 if ( count( $parts ) > 1 ) {
1537                         unset( $parts[count( $parts ) - 1] );
1538                 }
1539                 return implode( '/', $parts );
1540         }
1541
1542         /**
1543          * Get the base page name title, i.e. the part before the subpage name
1544          *
1545          * @par Example:
1546          * @code
1547          * Title::newFromText('User:Foo/Bar/Baz')->getBaseTitle();
1548          * # returns: Title{User:Foo/Bar}
1549          * @endcode
1550          *
1551          * @return Title Base title
1552          * @since 1.20
1553          */
1554         public function getBaseTitle() {
1555                 return Title::makeTitle( $this->getNamespace(), $this->getBaseText() );
1556         }
1557
1558         /**
1559          * Get the lowest-level subpage name, i.e. the rightmost part after any slashes
1560          *
1561          * @par Example:
1562          * @code
1563          * Title::newFromText('User:Foo/Bar/Baz')->getSubpageText();
1564          * # returns: "Baz"
1565          * @endcode
1566          *
1567          * @return string Subpage name
1568          */
1569         public function getSubpageText() {
1570                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1571                         return $this->mTextform;
1572                 }
1573                 $parts = explode( '/', $this->mTextform );
1574                 return $parts[count( $parts ) - 1];
1575         }
1576
1577         /**
1578          * Get the title for a subpage of the current page
1579          *
1580          * @par Example:
1581          * @code
1582          * Title::newFromText('User:Foo/Bar/Baz')->getSubpage("Asdf");
1583          * # returns: Title{User:Foo/Bar/Baz/Asdf}
1584          * @endcode
1585          *
1586          * @param string $text The subpage name to add to the title
1587          * @return Title Subpage title
1588          * @since 1.20
1589          */
1590         public function getSubpage( $text ) {
1591                 return Title::makeTitleSafe( $this->getNamespace(), $this->getText() . '/' . $text );
1592         }
1593
1594         /**
1595          * Get a URL-encoded form of the subpage text
1596          *
1597          * @return string URL-encoded subpage name
1598          */
1599         public function getSubpageUrlForm() {
1600                 $text = $this->getSubpageText();
1601                 $text = wfUrlencode( strtr( $text, ' ', '_' ) );
1602                 return $text;
1603         }
1604
1605         /**
1606          * Get a URL-encoded title (not an actual URL) including interwiki
1607          *
1608          * @return string The URL-encoded form
1609          */
1610         public function getPrefixedURL() {
1611                 $s = $this->prefix( $this->mDbkeyform );
1612                 $s = wfUrlencode( strtr( $s, ' ', '_' ) );
1613                 return $s;
1614         }
1615
1616         /**
1617          * Helper to fix up the get{Canonical,Full,Link,Local,Internal}URL args
1618          * get{Canonical,Full,Link,Local,Internal}URL methods accepted an optional
1619          * second argument named variant. This was deprecated in favor
1620          * of passing an array of option with a "variant" key
1621          * Once $query2 is removed for good, this helper can be dropped
1622          * and the wfArrayToCgi moved to getLocalURL();
1623          *
1624          * @since 1.19 (r105919)
1625          * @param array|string $query
1626          * @param string|string[]|bool $query2
1627          * @return string
1628          */
1629         private static function fixUrlQueryArgs( $query, $query2 = false ) {
1630                 if ( $query2 !== false ) {
1631                         wfDeprecated( "Title::get{Canonical,Full,Link,Local,Internal}URL " .
1632                                 "method called with a second parameter is deprecated. Add your " .
1633                                 "parameter to an array passed as the first parameter.", "1.19" );
1634                 }
1635                 if ( is_array( $query ) ) {
1636                         $query = wfArrayToCgi( $query );
1637                 }
1638                 if ( $query2 ) {
1639                         if ( is_string( $query2 ) ) {
1640                                 // $query2 is a string, we will consider this to be
1641                                 // a deprecated $variant argument and add it to the query
1642                                 $query2 = wfArrayToCgi( [ 'variant' => $query2 ] );
1643                         } else {
1644                                 $query2 = wfArrayToCgi( $query2 );
1645                         }
1646                         // If we have $query content add a & to it first
1647                         if ( $query ) {
1648                                 $query .= '&';
1649                         }
1650                         // Now append the queries together
1651                         $query .= $query2;
1652                 }
1653                 return $query;
1654         }
1655
1656         /**
1657          * Get a real URL referring to this title, with interwiki link and
1658          * fragment
1659          *
1660          * @see self::getLocalURL for the arguments.
1661          * @see wfExpandUrl
1662          * @param string|string[] $query
1663          * @param string|string[]|bool $query2
1664          * @param string $proto Protocol type to use in URL
1665          * @return string The URL
1666          */
1667         public function getFullURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1668                 $query = self::fixUrlQueryArgs( $query, $query2 );
1669
1670                 # Hand off all the decisions on urls to getLocalURL
1671                 $url = $this->getLocalURL( $query );
1672
1673                 # Expand the url to make it a full url. Note that getLocalURL has the
1674                 # potential to output full urls for a variety of reasons, so we use
1675                 # wfExpandUrl instead of simply prepending $wgServer
1676                 $url = wfExpandUrl( $url, $proto );
1677
1678                 # Finally, add the fragment.
1679                 $url .= $this->getFragmentForURL();
1680                 // Avoid PHP 7.1 warning from passing $this by reference
1681                 $titleRef = $this;
1682                 Hooks::run( 'GetFullURL', [ &$titleRef, &$url, $query ] );
1683                 return $url;
1684         }
1685
1686         /**
1687          * Get a url appropriate for making redirects based on an untrusted url arg
1688          *
1689          * This is basically the same as getFullUrl(), but in the case of external
1690          * interwikis, we send the user to a landing page, to prevent possible
1691          * phishing attacks and the like.
1692          *
1693          * @note Uses current protocol by default, since technically relative urls
1694          *   aren't allowed in redirects per HTTP spec, so this is not suitable for
1695          *   places where the url gets cached, as might pollute between
1696          *   https and non-https users.
1697          * @see self::getLocalURL for the arguments.
1698          * @param array|string $query
1699          * @param string $proto Protocol type to use in URL
1700          * @return String. A url suitable to use in an HTTP location header.
1701          */
1702         public function getFullUrlForRedirect( $query = '', $proto = PROTO_CURRENT ) {
1703                 $target = $this;
1704                 if ( $this->isExternal() ) {
1705                         $target = SpecialPage::getTitleFor(
1706                                 'GoToInterwiki',
1707                                 $this->getPrefixedDBKey()
1708                         );
1709                 }
1710                 return $target->getFullUrl( $query, false, $proto );
1711         }
1712
1713         /**
1714          * Get a URL with no fragment or server name (relative URL) from a Title object.
1715          * If this page is generated with action=render, however,
1716          * $wgServer is prepended to make an absolute URL.
1717          *
1718          * @see self::getFullURL to always get an absolute URL.
1719          * @see self::getLinkURL to always get a URL that's the simplest URL that will be
1720          *  valid to link, locally, to the current Title.
1721          * @see self::newFromText to produce a Title object.
1722          *
1723          * @param string|string[] $query An optional query string,
1724          *   not used for interwiki links. Can be specified as an associative array as well,
1725          *   e.g., array( 'action' => 'edit' ) (keys and values will be URL-escaped).
1726          *   Some query patterns will trigger various shorturl path replacements.
1727          * @param string|string[]|bool $query2 An optional secondary query array. This one MUST
1728          *   be an array. If a string is passed it will be interpreted as a deprecated
1729          *   variant argument and urlencoded into a variant= argument.
1730          *   This second query argument will be added to the $query
1731          *   The second parameter is deprecated since 1.19. Pass it as a key,value
1732          *   pair in the first parameter array instead.
1733          *
1734          * @return string String of the URL.
1735          */
1736         public function getLocalURL( $query = '', $query2 = false ) {
1737                 global $wgArticlePath, $wgScript, $wgServer, $wgRequest;
1738
1739                 $query = self::fixUrlQueryArgs( $query, $query2 );
1740
1741                 $interwiki = self::getInterwikiLookup()->fetch( $this->mInterwiki );
1742                 if ( $interwiki ) {
1743                         $namespace = $this->getNsText();
1744                         if ( $namespace != '' ) {
1745                                 # Can this actually happen? Interwikis shouldn't be parsed.
1746                                 # Yes! It can in interwiki transclusion. But... it probably shouldn't.
1747                                 $namespace .= ':';
1748                         }
1749                         $url = $interwiki->getURL( $namespace . $this->getDBkey() );
1750                         $url = wfAppendQuery( $url, $query );
1751                 } else {
1752                         $dbkey = wfUrlencode( $this->getPrefixedDBkey() );
1753                         if ( $query == '' ) {
1754                                 $url = str_replace( '$1', $dbkey, $wgArticlePath );
1755                                 // Avoid PHP 7.1 warning from passing $this by reference
1756                                 $titleRef = $this;
1757                                 Hooks::run( 'GetLocalURL::Article', [ &$titleRef, &$url ] );
1758                         } else {
1759                                 global $wgVariantArticlePath, $wgActionPaths, $wgContLang;
1760                                 $url = false;
1761                                 $matches = [];
1762
1763                                 if ( !empty( $wgActionPaths )
1764                                         && preg_match( '/^(.*&|)action=([^&]*)(&(.*)|)$/', $query, $matches )
1765                                 ) {
1766                                         $action = urldecode( $matches[2] );
1767                                         if ( isset( $wgActionPaths[$action] ) ) {
1768                                                 $query = $matches[1];
1769                                                 if ( isset( $matches[4] ) ) {
1770                                                         $query .= $matches[4];
1771                                                 }
1772                                                 $url = str_replace( '$1', $dbkey, $wgActionPaths[$action] );
1773                                                 if ( $query != '' ) {
1774                                                         $url = wfAppendQuery( $url, $query );
1775                                                 }
1776                                         }
1777                                 }
1778
1779                                 if ( $url === false
1780                                         && $wgVariantArticlePath
1781                                         && preg_match( '/^variant=([^&]*)$/', $query, $matches )
1782                                         && $this->getPageLanguage()->equals( $wgContLang )
1783                                         && $this->getPageLanguage()->hasVariants()
1784                                 ) {
1785                                         $variant = urldecode( $matches[1] );
1786                                         if ( $this->getPageLanguage()->hasVariant( $variant ) ) {
1787                                                 // Only do the variant replacement if the given variant is a valid
1788                                                 // variant for the page's language.
1789                                                 $url = str_replace( '$2', urlencode( $variant ), $wgVariantArticlePath );
1790                                                 $url = str_replace( '$1', $dbkey, $url );
1791                                         }
1792                                 }
1793
1794                                 if ( $url === false ) {
1795                                         if ( $query == '-' ) {
1796                                                 $query = '';
1797                                         }
1798                                         $url = "{$wgScript}?title={$dbkey}&{$query}";
1799                                 }
1800                         }
1801                         // Avoid PHP 7.1 warning from passing $this by reference
1802                         $titleRef = $this;
1803                         Hooks::run( 'GetLocalURL::Internal', [ &$titleRef, &$url, $query ] );
1804
1805                         // @todo FIXME: This causes breakage in various places when we
1806                         // actually expected a local URL and end up with dupe prefixes.
1807                         if ( $wgRequest->getVal( 'action' ) == 'render' ) {
1808                                 $url = $wgServer . $url;
1809                         }
1810                 }
1811                 // Avoid PHP 7.1 warning from passing $this by reference
1812                 $titleRef = $this;
1813                 Hooks::run( 'GetLocalURL', [ &$titleRef, &$url, $query ] );
1814                 return $url;
1815         }
1816
1817         /**
1818          * Get a URL that's the simplest URL that will be valid to link, locally,
1819          * to the current Title.  It includes the fragment, but does not include
1820          * the server unless action=render is used (or the link is external).  If
1821          * there's a fragment but the prefixed text is empty, we just return a link
1822          * to the fragment.
1823          *
1824          * The result obviously should not be URL-escaped, but does need to be
1825          * HTML-escaped if it's being output in HTML.
1826          *
1827          * @param string|string[] $query
1828          * @param bool $query2
1829          * @param string|int|bool $proto A PROTO_* constant on how the URL should be expanded,
1830          *                               or false (default) for no expansion
1831          * @see self::getLocalURL for the arguments.
1832          * @return string The URL
1833          */
1834         public function getLinkURL( $query = '', $query2 = false, $proto = false ) {
1835                 if ( $this->isExternal() || $proto !== false ) {
1836                         $ret = $this->getFullURL( $query, $query2, $proto );
1837                 } elseif ( $this->getPrefixedText() === '' && $this->hasFragment() ) {
1838                         $ret = $this->getFragmentForURL();
1839                 } else {
1840                         $ret = $this->getLocalURL( $query, $query2 ) . $this->getFragmentForURL();
1841                 }
1842                 return $ret;
1843         }
1844
1845         /**
1846          * Get the URL form for an internal link.
1847          * - Used in various CDN-related code, in case we have a different
1848          * internal hostname for the server from the exposed one.
1849          *
1850          * This uses $wgInternalServer to qualify the path, or $wgServer
1851          * if $wgInternalServer is not set. If the server variable used is
1852          * protocol-relative, the URL will be expanded to http://
1853          *
1854          * @see self::getLocalURL for the arguments.
1855          * @return string The URL
1856          */
1857         public function getInternalURL( $query = '', $query2 = false ) {
1858                 global $wgInternalServer, $wgServer;
1859                 $query = self::fixUrlQueryArgs( $query, $query2 );
1860                 $server = $wgInternalServer !== false ? $wgInternalServer : $wgServer;
1861                 $url = wfExpandUrl( $server . $this->getLocalURL( $query ), PROTO_HTTP );
1862                 // Avoid PHP 7.1 warning from passing $this by reference
1863                 $titleRef = $this;
1864                 Hooks::run( 'GetInternalURL', [ &$titleRef, &$url, $query ] );
1865                 return $url;
1866         }
1867
1868         /**
1869          * Get the URL for a canonical link, for use in things like IRC and
1870          * e-mail notifications. Uses $wgCanonicalServer and the
1871          * GetCanonicalURL hook.
1872          *
1873          * NOTE: Unlike getInternalURL(), the canonical URL includes the fragment
1874          *
1875          * @see self::getLocalURL for the arguments.
1876          * @return string The URL
1877          * @since 1.18
1878          */
1879         public function getCanonicalURL( $query = '', $query2 = false ) {
1880                 $query = self::fixUrlQueryArgs( $query, $query2 );
1881                 $url = wfExpandUrl( $this->getLocalURL( $query ) . $this->getFragmentForURL(), PROTO_CANONICAL );
1882                 // Avoid PHP 7.1 warning from passing $this by reference
1883                 $titleRef = $this;
1884                 Hooks::run( 'GetCanonicalURL', [ &$titleRef, &$url, $query ] );
1885                 return $url;
1886         }
1887
1888         /**
1889          * Get the edit URL for this Title
1890          *
1891          * @return string The URL, or a null string if this is an interwiki link
1892          */
1893         public function getEditURL() {
1894                 if ( $this->isExternal() ) {
1895                         return '';
1896                 }
1897                 $s = $this->getLocalURL( 'action=edit' );
1898
1899                 return $s;
1900         }
1901
1902         /**
1903          * Can $user perform $action on this page?
1904          * This skips potentially expensive cascading permission checks
1905          * as well as avoids expensive error formatting
1906          *
1907          * Suitable for use for nonessential UI controls in common cases, but
1908          * _not_ for functional access control.
1909          *
1910          * May provide false positives, but should never provide a false negative.
1911          *
1912          * @param string $action Action that permission needs to be checked for
1913          * @param User $user User to check (since 1.19); $wgUser will be used if not provided.
1914          * @return bool
1915          */
1916         public function quickUserCan( $action, $user = null ) {
1917                 return $this->userCan( $action, $user, false );
1918         }
1919
1920         /**
1921          * Can $user perform $action on this page?
1922          *
1923          * @param string $action Action that permission needs to be checked for
1924          * @param User $user User to check (since 1.19); $wgUser will be used if not
1925          *   provided.
1926          * @param string $rigor Same format as Title::getUserPermissionsErrors()
1927          * @return bool
1928          */
1929         public function userCan( $action, $user = null, $rigor = 'secure' ) {
1930                 if ( !$user instanceof User ) {
1931                         global $wgUser;
1932                         $user = $wgUser;
1933                 }
1934
1935                 return !count( $this->getUserPermissionsErrorsInternal( $action, $user, $rigor, true ) );
1936         }
1937
1938         /**
1939          * Can $user perform $action on this page?
1940          *
1941          * @todo FIXME: This *does not* check throttles (User::pingLimiter()).
1942          *
1943          * @param string $action Action that permission needs to be checked for
1944          * @param User $user User to check
1945          * @param string $rigor One of (quick,full,secure)
1946          *   - quick  : does cheap permission checks from replica DBs (usable for GUI creation)
1947          *   - full   : does cheap and expensive checks possibly from a replica DB
1948          *   - secure : does cheap and expensive checks, using the master as needed
1949          * @param array $ignoreErrors Array of Strings Set this to a list of message keys
1950          *   whose corresponding errors may be ignored.
1951          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
1952          */
1953         public function getUserPermissionsErrors(
1954                 $action, $user, $rigor = 'secure', $ignoreErrors = []
1955         ) {
1956                 $errors = $this->getUserPermissionsErrorsInternal( $action, $user, $rigor );
1957
1958                 // Remove the errors being ignored.
1959                 foreach ( $errors as $index => $error ) {
1960                         $errKey = is_array( $error ) ? $error[0] : $error;
1961
1962                         if ( in_array( $errKey, $ignoreErrors ) ) {
1963                                 unset( $errors[$index] );
1964                         }
1965                         if ( $errKey instanceof MessageSpecifier && in_array( $errKey->getKey(), $ignoreErrors ) ) {
1966                                 unset( $errors[$index] );
1967                         }
1968                 }
1969
1970                 return $errors;
1971         }
1972
1973         /**
1974          * Permissions checks that fail most often, and which are easiest to test.
1975          *
1976          * @param string $action The action to check
1977          * @param User $user User to check
1978          * @param array $errors List of current errors
1979          * @param string $rigor Same format as Title::getUserPermissionsErrors()
1980          * @param bool $short Short circuit on first error
1981          *
1982          * @return array List of errors
1983          */
1984         private function checkQuickPermissions( $action, $user, $errors, $rigor, $short ) {
1985                 if ( !Hooks::run( 'TitleQuickPermissions',
1986                         [ $this, $user, $action, &$errors, ( $rigor !== 'quick' ), $short ] )
1987                 ) {
1988                         return $errors;
1989                 }
1990
1991                 if ( $action == 'create' ) {
1992                         if (
1993                                 ( $this->isTalkPage() && !$user->isAllowed( 'createtalk' ) ) ||
1994                                 ( !$this->isTalkPage() && !$user->isAllowed( 'createpage' ) )
1995                         ) {
1996                                 $errors[] = $user->isAnon() ? [ 'nocreatetext' ] : [ 'nocreate-loggedin' ];
1997                         }
1998                 } elseif ( $action == 'move' ) {
1999                         if ( !$user->isAllowed( 'move-rootuserpages' )
2000                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
2001                                 // Show user page-specific message only if the user can move other pages
2002                                 $errors[] = [ 'cant-move-user-page' ];
2003                         }
2004
2005                         // Check if user is allowed to move files if it's a file
2006                         if ( $this->mNamespace == NS_FILE && !$user->isAllowed( 'movefile' ) ) {
2007                                 $errors[] = [ 'movenotallowedfile' ];
2008                         }
2009
2010                         // Check if user is allowed to move category pages if it's a category page
2011                         if ( $this->mNamespace == NS_CATEGORY && !$user->isAllowed( 'move-categorypages' ) ) {
2012                                 $errors[] = [ 'cant-move-category-page' ];
2013                         }
2014
2015                         if ( !$user->isAllowed( 'move' ) ) {
2016                                 // User can't move anything
2017                                 $userCanMove = User::groupHasPermission( 'user', 'move' );
2018                                 $autoconfirmedCanMove = User::groupHasPermission( 'autoconfirmed', 'move' );
2019                                 if ( $user->isAnon() && ( $userCanMove || $autoconfirmedCanMove ) ) {
2020                                         // custom message if logged-in users without any special rights can move
2021                                         $errors[] = [ 'movenologintext' ];
2022                                 } else {
2023                                         $errors[] = [ 'movenotallowed' ];
2024                                 }
2025                         }
2026                 } elseif ( $action == 'move-target' ) {
2027                         if ( !$user->isAllowed( 'move' ) ) {
2028                                 // User can't move anything
2029                                 $errors[] = [ 'movenotallowed' ];
2030                         } elseif ( !$user->isAllowed( 'move-rootuserpages' )
2031                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
2032                                 // Show user page-specific message only if the user can move other pages
2033                                 $errors[] = [ 'cant-move-to-user-page' ];
2034                         } elseif ( !$user->isAllowed( 'move-categorypages' )
2035                                         && $this->mNamespace == NS_CATEGORY ) {
2036                                 // Show category page-specific message only if the user can move other pages
2037                                 $errors[] = [ 'cant-move-to-category-page' ];
2038                         }
2039                 } elseif ( !$user->isAllowed( $action ) ) {
2040                         $errors[] = $this->missingPermissionError( $action, $short );
2041                 }
2042
2043                 return $errors;
2044         }
2045
2046         /**
2047          * Add the resulting error code to the errors array
2048          *
2049          * @param array $errors List of current errors
2050          * @param array $result Result of errors
2051          *
2052          * @return array List of errors
2053          */
2054         private function resultToError( $errors, $result ) {
2055                 if ( is_array( $result ) && count( $result ) && !is_array( $result[0] ) ) {
2056                         // A single array representing an error
2057                         $errors[] = $result;
2058                 } elseif ( is_array( $result ) && is_array( $result[0] ) ) {
2059                         // A nested array representing multiple errors
2060                         $errors = array_merge( $errors, $result );
2061                 } elseif ( $result !== '' && is_string( $result ) ) {
2062                         // A string representing a message-id
2063                         $errors[] = [ $result ];
2064                 } elseif ( $result instanceof MessageSpecifier ) {
2065                         // A message specifier representing an error
2066                         $errors[] = [ $result ];
2067                 } elseif ( $result === false ) {
2068                         // a generic "We don't want them to do that"
2069                         $errors[] = [ 'badaccess-group0' ];
2070                 }
2071                 return $errors;
2072         }
2073
2074         /**
2075          * Check various permission hooks
2076          *
2077          * @param string $action The action to check
2078          * @param User $user User to check
2079          * @param array $errors List of current errors
2080          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2081          * @param bool $short Short circuit on first error
2082          *
2083          * @return array List of errors
2084          */
2085         private function checkPermissionHooks( $action, $user, $errors, $rigor, $short ) {
2086                 // Use getUserPermissionsErrors instead
2087                 $result = '';
2088                 // Avoid PHP 7.1 warning from passing $this by reference
2089                 $titleRef = $this;
2090                 if ( !Hooks::run( 'userCan', [ &$titleRef, &$user, $action, &$result ] ) ) {
2091                         return $result ? [] : [ [ 'badaccess-group0' ] ];
2092                 }
2093                 // Check getUserPermissionsErrors hook
2094                 // Avoid PHP 7.1 warning from passing $this by reference
2095                 $titleRef = $this;
2096                 if ( !Hooks::run( 'getUserPermissionsErrors', [ &$titleRef, &$user, $action, &$result ] ) ) {
2097                         $errors = $this->resultToError( $errors, $result );
2098                 }
2099                 // Check getUserPermissionsErrorsExpensive hook
2100                 if (
2101                         $rigor !== 'quick'
2102                         && !( $short && count( $errors ) > 0 )
2103                         && !Hooks::run( 'getUserPermissionsErrorsExpensive', [ &$titleRef, &$user, $action, &$result ] )
2104                 ) {
2105                         $errors = $this->resultToError( $errors, $result );
2106                 }
2107
2108                 return $errors;
2109         }
2110
2111         /**
2112          * Check permissions on special pages & namespaces
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 checkSpecialsAndNSPermissions( $action, $user, $errors, $rigor, $short ) {
2123                 # Only 'createaccount' can be performed on special pages,
2124                 # which don't actually exist in the DB.
2125                 if ( NS_SPECIAL == $this->mNamespace && $action !== 'createaccount' ) {
2126                         $errors[] = [ 'ns-specialprotected' ];
2127                 }
2128
2129                 # Check $wgNamespaceProtection for restricted namespaces
2130                 if ( $this->isNamespaceProtected( $user ) ) {
2131                         $ns = $this->mNamespace == NS_MAIN ?
2132                                 wfMessage( 'nstab-main' )->text() : $this->getNsText();
2133                         $errors[] = $this->mNamespace == NS_MEDIAWIKI ?
2134                                 [ 'protectedinterface', $action ] : [ 'namespaceprotected', $ns, $action ];
2135                 }
2136
2137                 return $errors;
2138         }
2139
2140         /**
2141          * Check CSS/JS sub-page permissions
2142          *
2143          * @param string $action The action to check
2144          * @param User $user User to check
2145          * @param array $errors List of current errors
2146          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2147          * @param bool $short Short circuit on first error
2148          *
2149          * @return array List of errors
2150          */
2151         private function checkCSSandJSPermissions( $action, $user, $errors, $rigor, $short ) {
2152                 # Protect css/js subpages of user pages
2153                 # XXX: this might be better using restrictions
2154                 # XXX: right 'editusercssjs' is deprecated, for backward compatibility only
2155                 if ( $action != 'patrol' && !$user->isAllowed( 'editusercssjs' ) ) {
2156                         if ( preg_match( '/^' . preg_quote( $user->getName(), '/' ) . '\//', $this->mTextform ) ) {
2157                                 if ( $this->isCssSubpage() && !$user->isAllowedAny( 'editmyusercss', 'editusercss' ) ) {
2158                                         $errors[] = [ 'mycustomcssprotected', $action ];
2159                                 } elseif ( $this->isJsSubpage() && !$user->isAllowedAny( 'editmyuserjs', 'edituserjs' ) ) {
2160                                         $errors[] = [ 'mycustomjsprotected', $action ];
2161                                 }
2162                         } else {
2163                                 if ( $this->isCssSubpage() && !$user->isAllowed( 'editusercss' ) ) {
2164                                         $errors[] = [ 'customcssprotected', $action ];
2165                                 } elseif ( $this->isJsSubpage() && !$user->isAllowed( 'edituserjs' ) ) {
2166                                         $errors[] = [ 'customjsprotected', $action ];
2167                                 }
2168                         }
2169                 }
2170
2171                 return $errors;
2172         }
2173
2174         /**
2175          * Check against page_restrictions table requirements on this
2176          * page. The user must possess all required rights for this
2177          * action.
2178          *
2179          * @param string $action The action to check
2180          * @param User $user User to check
2181          * @param array $errors List of current errors
2182          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2183          * @param bool $short Short circuit on first error
2184          *
2185          * @return array List of errors
2186          */
2187         private function checkPageRestrictions( $action, $user, $errors, $rigor, $short ) {
2188                 foreach ( $this->getRestrictions( $action ) as $right ) {
2189                         // Backwards compatibility, rewrite sysop -> editprotected
2190                         if ( $right == 'sysop' ) {
2191                                 $right = 'editprotected';
2192                         }
2193                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2194                         if ( $right == 'autoconfirmed' ) {
2195                                 $right = 'editsemiprotected';
2196                         }
2197                         if ( $right == '' ) {
2198                                 continue;
2199                         }
2200                         if ( !$user->isAllowed( $right ) ) {
2201                                 $errors[] = [ 'protectedpagetext', $right, $action ];
2202                         } elseif ( $this->mCascadeRestriction && !$user->isAllowed( 'protect' ) ) {
2203                                 $errors[] = [ 'protectedpagetext', 'protect', $action ];
2204                         }
2205                 }
2206
2207                 return $errors;
2208         }
2209
2210         /**
2211          * Check restrictions on cascading pages.
2212          *
2213          * @param string $action The action to check
2214          * @param User $user User to check
2215          * @param array $errors List of current errors
2216          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2217          * @param bool $short Short circuit on first error
2218          *
2219          * @return array List of errors
2220          */
2221         private function checkCascadingSourcesRestrictions( $action, $user, $errors, $rigor, $short ) {
2222                 if ( $rigor !== 'quick' && !$this->isCssJsSubpage() ) {
2223                         # We /could/ use the protection level on the source page, but it's
2224                         # fairly ugly as we have to establish a precedence hierarchy for pages
2225                         # included by multiple cascade-protected pages. So just restrict
2226                         # it to people with 'protect' permission, as they could remove the
2227                         # protection anyway.
2228                         list( $cascadingSources, $restrictions ) = $this->getCascadeProtectionSources();
2229                         # Cascading protection depends on more than this page...
2230                         # Several cascading protected pages may include this page...
2231                         # Check each cascading level
2232                         # This is only for protection restrictions, not for all actions
2233                         if ( isset( $restrictions[$action] ) ) {
2234                                 foreach ( $restrictions[$action] as $right ) {
2235                                         // Backwards compatibility, rewrite sysop -> editprotected
2236                                         if ( $right == 'sysop' ) {
2237                                                 $right = 'editprotected';
2238                                         }
2239                                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2240                                         if ( $right == 'autoconfirmed' ) {
2241                                                 $right = 'editsemiprotected';
2242                                         }
2243                                         if ( $right != '' && !$user->isAllowedAll( 'protect', $right ) ) {
2244                                                 $pages = '';
2245                                                 foreach ( $cascadingSources as $page ) {
2246                                                         $pages .= '* [[:' . $page->getPrefixedText() . "]]\n";
2247                                                 }
2248                                                 $errors[] = [ 'cascadeprotected', count( $cascadingSources ), $pages, $action ];
2249                                         }
2250                                 }
2251                         }
2252                 }
2253
2254                 return $errors;
2255         }
2256
2257         /**
2258          * Check action permissions not already checked in checkQuickPermissions
2259          *
2260          * @param string $action The action to check
2261          * @param User $user User to check
2262          * @param array $errors List of current errors
2263          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2264          * @param bool $short Short circuit on first error
2265          *
2266          * @return array List of errors
2267          */
2268         private function checkActionPermissions( $action, $user, $errors, $rigor, $short ) {
2269                 global $wgDeleteRevisionsLimit, $wgLang;
2270
2271                 if ( $action == 'protect' ) {
2272                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit', $user, $rigor, true ) ) ) {
2273                                 // If they can't edit, they shouldn't protect.
2274                                 $errors[] = [ 'protect-cantedit' ];
2275                         }
2276                 } elseif ( $action == 'create' ) {
2277                         $title_protection = $this->getTitleProtection();
2278                         if ( $title_protection ) {
2279                                 if ( $title_protection['permission'] == ''
2280                                         || !$user->isAllowed( $title_protection['permission'] )
2281                                 ) {
2282                                         $errors[] = [
2283                                                 'titleprotected',
2284                                                 User::whoIs( $title_protection['user'] ),
2285                                                 $title_protection['reason']
2286                                         ];
2287                                 }
2288                         }
2289                 } elseif ( $action == 'move' ) {
2290                         // Check for immobile pages
2291                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2292                                 // Specific message for this case
2293                                 $errors[] = [ 'immobile-source-namespace', $this->getNsText() ];
2294                         } elseif ( !$this->isMovable() ) {
2295                                 // Less specific message for rarer cases
2296                                 $errors[] = [ 'immobile-source-page' ];
2297                         }
2298                 } elseif ( $action == 'move-target' ) {
2299                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2300                                 $errors[] = [ 'immobile-target-namespace', $this->getNsText() ];
2301                         } elseif ( !$this->isMovable() ) {
2302                                 $errors[] = [ 'immobile-target-page' ];
2303                         }
2304                 } elseif ( $action == 'delete' ) {
2305                         $tempErrors = $this->checkPageRestrictions( 'edit', $user, [], $rigor, true );
2306                         if ( !$tempErrors ) {
2307                                 $tempErrors = $this->checkCascadingSourcesRestrictions( 'edit',
2308                                         $user, $tempErrors, $rigor, true );
2309                         }
2310                         if ( $tempErrors ) {
2311                                 // If protection keeps them from editing, they shouldn't be able to delete.
2312                                 $errors[] = [ 'deleteprotected' ];
2313                         }
2314                         if ( $rigor !== 'quick' && $wgDeleteRevisionsLimit
2315                                 && !$this->userCan( 'bigdelete', $user ) && $this->isBigDeletion()
2316                         ) {
2317                                 $errors[] = [ 'delete-toobig', $wgLang->formatNum( $wgDeleteRevisionsLimit ) ];
2318                         }
2319                 }
2320                 return $errors;
2321         }
2322
2323         /**
2324          * Check that the user isn't blocked from editing.
2325          *
2326          * @param string $action The action to check
2327          * @param User $user User to check
2328          * @param array $errors List of current errors
2329          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2330          * @param bool $short Short circuit on first error
2331          *
2332          * @return array List of errors
2333          */
2334         private function checkUserBlock( $action, $user, $errors, $rigor, $short ) {
2335                 global $wgEmailConfirmToEdit, $wgBlockDisablesLogin;
2336                 // Account creation blocks handled at userlogin.
2337                 // Unblocking handled in SpecialUnblock
2338                 if ( $rigor === 'quick' || in_array( $action, [ 'createaccount', 'unblock' ] ) ) {
2339                         return $errors;
2340                 }
2341
2342                 // Optimize for a very common case
2343                 if ( $action === 'read' && !$wgBlockDisablesLogin ) {
2344                         return $errors;
2345                 }
2346
2347                 if ( $wgEmailConfirmToEdit && !$user->isEmailConfirmed() ) {
2348                         $errors[] = [ 'confirmedittext' ];
2349                 }
2350
2351                 $useSlave = ( $rigor !== 'secure' );
2352                 if ( ( $action == 'edit' || $action == 'create' )
2353                         && !$user->isBlockedFrom( $this, $useSlave )
2354                 ) {
2355                         // Don't block the user from editing their own talk page unless they've been
2356                         // explicitly blocked from that too.
2357                 } elseif ( $user->isBlocked() && $user->getBlock()->prevents( $action ) !== false ) {
2358                         // @todo FIXME: Pass the relevant context into this function.
2359                         $errors[] = $user->getBlock()->getPermissionsError( RequestContext::getMain() );
2360                 }
2361
2362                 return $errors;
2363         }
2364
2365         /**
2366          * Check that the user is allowed to read this page.
2367          *
2368          * @param string $action The action to check
2369          * @param User $user User to check
2370          * @param array $errors List of current errors
2371          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2372          * @param bool $short Short circuit on first error
2373          *
2374          * @return array List of errors
2375          */
2376         private function checkReadPermissions( $action, $user, $errors, $rigor, $short ) {
2377                 global $wgWhitelistRead, $wgWhitelistReadRegexp;
2378
2379                 $whitelisted = false;
2380                 if ( User::isEveryoneAllowed( 'read' ) ) {
2381                         # Shortcut for public wikis, allows skipping quite a bit of code
2382                         $whitelisted = true;
2383                 } elseif ( $user->isAllowed( 'read' ) ) {
2384                         # If the user is allowed to read pages, he is allowed to read all pages
2385                         $whitelisted = true;
2386                 } elseif ( $this->isSpecial( 'Userlogin' )
2387                         || $this->isSpecial( 'PasswordReset' )
2388                         || $this->isSpecial( 'Userlogout' )
2389                 ) {
2390                         # Always grant access to the login page.
2391                         # Even anons need to be able to log in.
2392                         $whitelisted = true;
2393                 } elseif ( is_array( $wgWhitelistRead ) && count( $wgWhitelistRead ) ) {
2394                         # Time to check the whitelist
2395                         # Only do these checks is there's something to check against
2396                         $name = $this->getPrefixedText();
2397                         $dbName = $this->getPrefixedDBkey();
2398
2399                         // Check for explicit whitelisting with and without underscores
2400                         if ( in_array( $name, $wgWhitelistRead, true ) || in_array( $dbName, $wgWhitelistRead, true ) ) {
2401                                 $whitelisted = true;
2402                         } elseif ( $this->getNamespace() == NS_MAIN ) {
2403                                 # Old settings might have the title prefixed with
2404                                 # a colon for main-namespace pages
2405                                 if ( in_array( ':' . $name, $wgWhitelistRead ) ) {
2406                                         $whitelisted = true;
2407                                 }
2408                         } elseif ( $this->isSpecialPage() ) {
2409                                 # If it's a special page, ditch the subpage bit and check again
2410                                 $name = $this->getDBkey();
2411                                 list( $name, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $name );
2412                                 if ( $name ) {
2413                                         $pure = SpecialPage::getTitleFor( $name )->getPrefixedText();
2414                                         if ( in_array( $pure, $wgWhitelistRead, true ) ) {
2415                                                 $whitelisted = true;
2416                                         }
2417                                 }
2418                         }
2419                 }
2420
2421                 if ( !$whitelisted && is_array( $wgWhitelistReadRegexp ) && !empty( $wgWhitelistReadRegexp ) ) {
2422                         $name = $this->getPrefixedText();
2423                         // Check for regex whitelisting
2424                         foreach ( $wgWhitelistReadRegexp as $listItem ) {
2425                                 if ( preg_match( $listItem, $name ) ) {
2426                                         $whitelisted = true;
2427                                         break;
2428                                 }
2429                         }
2430                 }
2431
2432                 if ( !$whitelisted ) {
2433                         # If the title is not whitelisted, give extensions a chance to do so...
2434                         Hooks::run( 'TitleReadWhitelist', [ $this, $user, &$whitelisted ] );
2435                         if ( !$whitelisted ) {
2436                                 $errors[] = $this->missingPermissionError( $action, $short );
2437                         }
2438                 }
2439
2440                 return $errors;
2441         }
2442
2443         /**
2444          * Get a description array when the user doesn't have the right to perform
2445          * $action (i.e. when User::isAllowed() returns false)
2446          *
2447          * @param string $action The action to check
2448          * @param bool $short Short circuit on first error
2449          * @return array Array containing an error message key and any parameters
2450          */
2451         private function missingPermissionError( $action, $short ) {
2452                 // We avoid expensive display logic for quickUserCan's and such
2453                 if ( $short ) {
2454                         return [ 'badaccess-group0' ];
2455                 }
2456
2457                 return User::newFatalPermissionDeniedStatus( $action )->getErrorsArray()[0];
2458         }
2459
2460         /**
2461          * Can $user perform $action on this page? This is an internal function,
2462          * with multiple levels of checks depending on performance needs; see $rigor below.
2463          * It does not check wfReadOnly().
2464          *
2465          * @param string $action Action that permission needs to be checked for
2466          * @param User $user User to check
2467          * @param string $rigor One of (quick,full,secure)
2468          *   - quick  : does cheap permission checks from replica DBs (usable for GUI creation)
2469          *   - full   : does cheap and expensive checks possibly from a replica DB
2470          *   - secure : does cheap and expensive checks, using the master as needed
2471          * @param bool $short Set this to true to stop after the first permission error.
2472          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
2473          */
2474         protected function getUserPermissionsErrorsInternal(
2475                 $action, $user, $rigor = 'secure', $short = false
2476         ) {
2477                 if ( $rigor === true ) {
2478                         $rigor = 'secure'; // b/c
2479                 } elseif ( $rigor === false ) {
2480                         $rigor = 'quick'; // b/c
2481                 } elseif ( !in_array( $rigor, [ 'quick', 'full', 'secure' ] ) ) {
2482                         throw new Exception( "Invalid rigor parameter '$rigor'." );
2483                 }
2484
2485                 # Read has special handling
2486                 if ( $action == 'read' ) {
2487                         $checks = [
2488                                 'checkPermissionHooks',
2489                                 'checkReadPermissions',
2490                                 'checkUserBlock', // for wgBlockDisablesLogin
2491                         ];
2492                 # Don't call checkSpecialsAndNSPermissions or checkCSSandJSPermissions
2493                 # here as it will lead to duplicate error messages. This is okay to do
2494                 # since anywhere that checks for create will also check for edit, and
2495                 # those checks are called for edit.
2496                 } elseif ( $action == 'create' ) {
2497                         $checks = [
2498                                 'checkQuickPermissions',
2499                                 'checkPermissionHooks',
2500                                 'checkPageRestrictions',
2501                                 'checkCascadingSourcesRestrictions',
2502                                 'checkActionPermissions',
2503                                 'checkUserBlock'
2504                         ];
2505                 } else {
2506                         $checks = [
2507                                 'checkQuickPermissions',
2508                                 'checkPermissionHooks',
2509                                 'checkSpecialsAndNSPermissions',
2510                                 'checkCSSandJSPermissions',
2511                                 'checkPageRestrictions',
2512                                 'checkCascadingSourcesRestrictions',
2513                                 'checkActionPermissions',
2514                                 'checkUserBlock'
2515                         ];
2516                 }
2517
2518                 $errors = [];
2519                 while ( count( $checks ) > 0 &&
2520                                 !( $short && count( $errors ) > 0 ) ) {
2521                         $method = array_shift( $checks );
2522                         $errors = $this->$method( $action, $user, $errors, $rigor, $short );
2523                 }
2524
2525                 return $errors;
2526         }
2527
2528         /**
2529          * Get a filtered list of all restriction types supported by this wiki.
2530          * @param bool $exists True to get all restriction types that apply to
2531          * titles that do exist, False for all restriction types that apply to
2532          * titles that do not exist
2533          * @return array
2534          */
2535         public static function getFilteredRestrictionTypes( $exists = true ) {
2536                 global $wgRestrictionTypes;
2537                 $types = $wgRestrictionTypes;
2538                 if ( $exists ) {
2539                         # Remove the create restriction for existing titles
2540                         $types = array_diff( $types, [ 'create' ] );
2541                 } else {
2542                         # Only the create and upload restrictions apply to non-existing titles
2543                         $types = array_intersect( $types, [ 'create', 'upload' ] );
2544                 }
2545                 return $types;
2546         }
2547
2548         /**
2549          * Returns restriction types for the current Title
2550          *
2551          * @return array Applicable restriction types
2552          */
2553         public function getRestrictionTypes() {
2554                 if ( $this->isSpecialPage() ) {
2555                         return [];
2556                 }
2557
2558                 $types = self::getFilteredRestrictionTypes( $this->exists() );
2559
2560                 if ( $this->getNamespace() != NS_FILE ) {
2561                         # Remove the upload restriction for non-file titles
2562                         $types = array_diff( $types, [ 'upload' ] );
2563                 }
2564
2565                 Hooks::run( 'TitleGetRestrictionTypes', [ $this, &$types ] );
2566
2567                 wfDebug( __METHOD__ . ': applicable restrictions to [[' .
2568                         $this->getPrefixedText() . ']] are {' . implode( ',', $types ) . "}\n" );
2569
2570                 return $types;
2571         }
2572
2573         /**
2574          * Is this title subject to title protection?
2575          * Title protection is the one applied against creation of such title.
2576          *
2577          * @return array|bool An associative array representing any existent title
2578          *   protection, or false if there's none.
2579          */
2580         public function getTitleProtection() {
2581                 $protection = $this->getTitleProtectionInternal();
2582                 if ( $protection ) {
2583                         if ( $protection['permission'] == 'sysop' ) {
2584                                 $protection['permission'] = 'editprotected'; // B/C
2585                         }
2586                         if ( $protection['permission'] == 'autoconfirmed' ) {
2587                                 $protection['permission'] = 'editsemiprotected'; // B/C
2588                         }
2589                 }
2590                 return $protection;
2591         }
2592
2593         /**
2594          * Fetch title protection settings
2595          *
2596          * To work correctly, $this->loadRestrictions() needs to have access to the
2597          * actual protections in the database without munging 'sysop' =>
2598          * 'editprotected' and 'autoconfirmed' => 'editsemiprotected'. Other
2599          * callers probably want $this->getTitleProtection() instead.
2600          *
2601          * @return array|bool
2602          */
2603         protected function getTitleProtectionInternal() {
2604                 // Can't protect pages in special namespaces
2605                 if ( $this->getNamespace() < 0 ) {
2606                         return false;
2607                 }
2608
2609                 // Can't protect pages that exist.
2610                 if ( $this->exists() ) {
2611                         return false;
2612                 }
2613
2614                 if ( $this->mTitleProtection === null ) {
2615                         $dbr = wfGetDB( DB_REPLICA );
2616                         $res = $dbr->select(
2617                                 'protected_titles',
2618                                 [
2619                                         'user' => 'pt_user',
2620                                         'reason' => 'pt_reason',
2621                                         'expiry' => 'pt_expiry',
2622                                         'permission' => 'pt_create_perm'
2623                                 ],
2624                                 [ 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ],
2625                                 __METHOD__
2626                         );
2627
2628                         // fetchRow returns false if there are no rows.
2629                         $row = $dbr->fetchRow( $res );
2630                         if ( $row ) {
2631                                 $row['expiry'] = $dbr->decodeExpiry( $row['expiry'] );
2632                         }
2633                         $this->mTitleProtection = $row;
2634                 }
2635                 return $this->mTitleProtection;
2636         }
2637
2638         /**
2639          * Remove any title protection due to page existing
2640          */
2641         public function deleteTitleProtection() {
2642                 $dbw = wfGetDB( DB_MASTER );
2643
2644                 $dbw->delete(
2645                         'protected_titles',
2646                         [ 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ],
2647                         __METHOD__
2648                 );
2649                 $this->mTitleProtection = false;
2650         }
2651
2652         /**
2653          * Is this page "semi-protected" - the *only* protection levels are listed
2654          * in $wgSemiprotectedRestrictionLevels?
2655          *
2656          * @param string $action Action to check (default: edit)
2657          * @return bool
2658          */
2659         public function isSemiProtected( $action = 'edit' ) {
2660                 global $wgSemiprotectedRestrictionLevels;
2661
2662                 $restrictions = $this->getRestrictions( $action );
2663                 $semi = $wgSemiprotectedRestrictionLevels;
2664                 if ( !$restrictions || !$semi ) {
2665                         // Not protected, or all protection is full protection
2666                         return false;
2667                 }
2668
2669                 // Remap autoconfirmed to editsemiprotected for BC
2670                 foreach ( array_keys( $semi, 'autoconfirmed' ) as $key ) {
2671                         $semi[$key] = 'editsemiprotected';
2672                 }
2673                 foreach ( array_keys( $restrictions, 'autoconfirmed' ) as $key ) {
2674                         $restrictions[$key] = 'editsemiprotected';
2675                 }
2676
2677                 return !array_diff( $restrictions, $semi );
2678         }
2679
2680         /**
2681          * Does the title correspond to a protected article?
2682          *
2683          * @param string $action The action the page is protected from,
2684          * by default checks all actions.
2685          * @return bool
2686          */
2687         public function isProtected( $action = '' ) {
2688                 global $wgRestrictionLevels;
2689
2690                 $restrictionTypes = $this->getRestrictionTypes();
2691
2692                 # Special pages have inherent protection
2693                 if ( $this->isSpecialPage() ) {
2694                         return true;
2695                 }
2696
2697                 # Check regular protection levels
2698                 foreach ( $restrictionTypes as $type ) {
2699                         if ( $action == $type || $action == '' ) {
2700                                 $r = $this->getRestrictions( $type );
2701                                 foreach ( $wgRestrictionLevels as $level ) {
2702                                         if ( in_array( $level, $r ) && $level != '' ) {
2703                                                 return true;
2704                                         }
2705                                 }
2706                         }
2707                 }
2708
2709                 return false;
2710         }
2711
2712         /**
2713          * Determines if $user is unable to edit this page because it has been protected
2714          * by $wgNamespaceProtection.
2715          *
2716          * @param User $user User object to check permissions
2717          * @return bool
2718          */
2719         public function isNamespaceProtected( User $user ) {
2720                 global $wgNamespaceProtection;
2721
2722                 if ( isset( $wgNamespaceProtection[$this->mNamespace] ) ) {
2723                         foreach ( (array)$wgNamespaceProtection[$this->mNamespace] as $right ) {
2724                                 if ( $right != '' && !$user->isAllowed( $right ) ) {
2725                                         return true;
2726                                 }
2727                         }
2728                 }
2729                 return false;
2730         }
2731
2732         /**
2733          * Cascading protection: Return true if cascading restrictions apply to this page, false if not.
2734          *
2735          * @return bool If the page is subject to cascading restrictions.
2736          */
2737         public function isCascadeProtected() {
2738                 list( $sources, /* $restrictions */ ) = $this->getCascadeProtectionSources( false );
2739                 return ( $sources > 0 );
2740         }
2741
2742         /**
2743          * Determines whether cascading protection sources have already been loaded from
2744          * the database.
2745          *
2746          * @param bool $getPages True to check if the pages are loaded, or false to check
2747          * if the status is loaded.
2748          * @return bool Whether or not the specified information has been loaded
2749          * @since 1.23
2750          */
2751         public function areCascadeProtectionSourcesLoaded( $getPages = true ) {
2752                 return $getPages ? $this->mCascadeSources !== null : $this->mHasCascadingRestrictions !== null;
2753         }
2754
2755         /**
2756          * Cascading protection: Get the source of any cascading restrictions on this page.
2757          *
2758          * @param bool $getPages Whether or not to retrieve the actual pages
2759          *        that the restrictions have come from and the actual restrictions
2760          *        themselves.
2761          * @return array Two elements: First is an array of Title objects of the
2762          *        pages from which cascading restrictions have come, false for
2763          *        none, or true if such restrictions exist but $getPages was not
2764          *        set. Second is an array like that returned by
2765          *        Title::getAllRestrictions(), or an empty array if $getPages is
2766          *        false.
2767          */
2768         public function getCascadeProtectionSources( $getPages = true ) {
2769                 $pagerestrictions = [];
2770
2771                 if ( $this->mCascadeSources !== null && $getPages ) {
2772                         return [ $this->mCascadeSources, $this->mCascadingRestrictions ];
2773                 } elseif ( $this->mHasCascadingRestrictions !== null && !$getPages ) {
2774                         return [ $this->mHasCascadingRestrictions, $pagerestrictions ];
2775                 }
2776
2777                 $dbr = wfGetDB( DB_REPLICA );
2778
2779                 if ( $this->getNamespace() == NS_FILE ) {
2780                         $tables = [ 'imagelinks', 'page_restrictions' ];
2781                         $where_clauses = [
2782                                 'il_to' => $this->getDBkey(),
2783                                 'il_from=pr_page',
2784                                 'pr_cascade' => 1
2785                         ];
2786                 } else {
2787                         $tables = [ 'templatelinks', 'page_restrictions' ];
2788                         $where_clauses = [
2789                                 'tl_namespace' => $this->getNamespace(),
2790                                 'tl_title' => $this->getDBkey(),
2791                                 'tl_from=pr_page',
2792                                 'pr_cascade' => 1
2793                         ];
2794                 }
2795
2796                 if ( $getPages ) {
2797                         $cols = [ 'pr_page', 'page_namespace', 'page_title',
2798                                 'pr_expiry', 'pr_type', 'pr_level' ];
2799                         $where_clauses[] = 'page_id=pr_page';
2800                         $tables[] = 'page';
2801                 } else {
2802                         $cols = [ 'pr_expiry' ];
2803                 }
2804
2805                 $res = $dbr->select( $tables, $cols, $where_clauses, __METHOD__ );
2806
2807                 $sources = $getPages ? [] : false;
2808                 $now = wfTimestampNow();
2809
2810                 foreach ( $res as $row ) {
2811                         $expiry = $dbr->decodeExpiry( $row->pr_expiry );
2812                         if ( $expiry > $now ) {
2813                                 if ( $getPages ) {
2814                                         $page_id = $row->pr_page;
2815                                         $page_ns = $row->page_namespace;
2816                                         $page_title = $row->page_title;
2817                                         $sources[$page_id] = Title::makeTitle( $page_ns, $page_title );
2818                                         # Add groups needed for each restriction type if its not already there
2819                                         # Make sure this restriction type still exists
2820
2821                                         if ( !isset( $pagerestrictions[$row->pr_type] ) ) {
2822                                                 $pagerestrictions[$row->pr_type] = [];
2823                                         }
2824
2825                                         if (
2826                                                 isset( $pagerestrictions[$row->pr_type] )
2827                                                 && !in_array( $row->pr_level, $pagerestrictions[$row->pr_type] )
2828                                         ) {
2829                                                 $pagerestrictions[$row->pr_type][] = $row->pr_level;
2830                                         }
2831                                 } else {
2832                                         $sources = true;
2833                                 }
2834                         }
2835                 }
2836
2837                 if ( $getPages ) {
2838                         $this->mCascadeSources = $sources;
2839                         $this->mCascadingRestrictions = $pagerestrictions;
2840                 } else {
2841                         $this->mHasCascadingRestrictions = $sources;
2842                 }
2843
2844                 return [ $sources, $pagerestrictions ];
2845         }
2846
2847         /**
2848          * Accessor for mRestrictionsLoaded
2849          *
2850          * @return bool Whether or not the page's restrictions have already been
2851          * loaded from the database
2852          * @since 1.23
2853          */
2854         public function areRestrictionsLoaded() {
2855                 return $this->mRestrictionsLoaded;
2856         }
2857
2858         /**
2859          * Accessor/initialisation for mRestrictions
2860          *
2861          * @param string $action Action that permission needs to be checked for
2862          * @return array Restriction levels needed to take the action. All levels are
2863          *     required. Note that restriction levels are normally user rights, but 'sysop'
2864          *     and 'autoconfirmed' are also allowed for backwards compatibility. These should
2865          *     be mapped to 'editprotected' and 'editsemiprotected' respectively.
2866          */
2867         public function getRestrictions( $action ) {
2868                 if ( !$this->mRestrictionsLoaded ) {
2869                         $this->loadRestrictions();
2870                 }
2871                 return isset( $this->mRestrictions[$action] )
2872                                 ? $this->mRestrictions[$action]
2873                                 : [];
2874         }
2875
2876         /**
2877          * Accessor/initialisation for mRestrictions
2878          *
2879          * @return array Keys are actions, values are arrays as returned by
2880          *     Title::getRestrictions()
2881          * @since 1.23
2882          */
2883         public function getAllRestrictions() {
2884                 if ( !$this->mRestrictionsLoaded ) {
2885                         $this->loadRestrictions();
2886                 }
2887                 return $this->mRestrictions;
2888         }
2889
2890         /**
2891          * Get the expiry time for the restriction against a given action
2892          *
2893          * @param string $action
2894          * @return string|bool 14-char timestamp, or 'infinity' if the page is protected forever
2895          *     or not protected at all, or false if the action is not recognised.
2896          */
2897         public function getRestrictionExpiry( $action ) {
2898                 if ( !$this->mRestrictionsLoaded ) {
2899                         $this->loadRestrictions();
2900                 }
2901                 return isset( $this->mRestrictionsExpiry[$action] ) ? $this->mRestrictionsExpiry[$action] : false;
2902         }
2903
2904         /**
2905          * Returns cascading restrictions for the current article
2906          *
2907          * @return bool
2908          */
2909         function areRestrictionsCascading() {
2910                 if ( !$this->mRestrictionsLoaded ) {
2911                         $this->loadRestrictions();
2912                 }
2913
2914                 return $this->mCascadeRestriction;
2915         }
2916
2917         /**
2918          * Compiles list of active page restrictions from both page table (pre 1.10)
2919          * and page_restrictions table for this existing page.
2920          * Public for usage by LiquidThreads.
2921          *
2922          * @param array $rows Array of db result objects
2923          * @param string $oldFashionedRestrictions Comma-separated list of page
2924          *   restrictions from page table (pre 1.10)
2925          */
2926         public function loadRestrictionsFromRows( $rows, $oldFashionedRestrictions = null ) {
2927                 $dbr = wfGetDB( DB_REPLICA );
2928
2929                 $restrictionTypes = $this->getRestrictionTypes();
2930
2931                 foreach ( $restrictionTypes as $type ) {
2932                         $this->mRestrictions[$type] = [];
2933                         $this->mRestrictionsExpiry[$type] = 'infinity';
2934                 }
2935
2936                 $this->mCascadeRestriction = false;
2937
2938                 # Backwards-compatibility: also load the restrictions from the page record (old format).
2939                 if ( $oldFashionedRestrictions !== null ) {
2940                         $this->mOldRestrictions = $oldFashionedRestrictions;
2941                 }
2942
2943                 if ( $this->mOldRestrictions === false ) {
2944                         $this->mOldRestrictions = $dbr->selectField( 'page', 'page_restrictions',
2945                                 [ 'page_id' => $this->getArticleID() ], __METHOD__ );
2946                 }
2947
2948                 if ( $this->mOldRestrictions != '' ) {
2949                         foreach ( explode( ':', trim( $this->mOldRestrictions ) ) as $restrict ) {
2950                                 $temp = explode( '=', trim( $restrict ) );
2951                                 if ( count( $temp ) == 1 ) {
2952                                         // old old format should be treated as edit/move restriction
2953                                         $this->mRestrictions['edit'] = explode( ',', trim( $temp[0] ) );
2954                                         $this->mRestrictions['move'] = explode( ',', trim( $temp[0] ) );
2955                                 } else {
2956                                         $restriction = trim( $temp[1] );
2957                                         if ( $restriction != '' ) { // some old entries are empty
2958                                                 $this->mRestrictions[$temp[0]] = explode( ',', $restriction );
2959                                         }
2960                                 }
2961                         }
2962                 }
2963
2964                 if ( count( $rows ) ) {
2965                         # Current system - load second to make them override.
2966                         $now = wfTimestampNow();
2967
2968                         # Cycle through all the restrictions.
2969                         foreach ( $rows as $row ) {
2970                                 // Don't take care of restrictions types that aren't allowed
2971                                 if ( !in_array( $row->pr_type, $restrictionTypes ) ) {
2972                                         continue;
2973                                 }
2974
2975                                 $expiry = $dbr->decodeExpiry( $row->pr_expiry );
2976
2977                                 // Only apply the restrictions if they haven't expired!
2978                                 if ( !$expiry || $expiry > $now ) {
2979                                         $this->mRestrictionsExpiry[$row->pr_type] = $expiry;
2980                                         $this->mRestrictions[$row->pr_type] = explode( ',', trim( $row->pr_level ) );
2981
2982                                         $this->mCascadeRestriction |= $row->pr_cascade;
2983                                 }
2984                         }
2985                 }
2986
2987                 $this->mRestrictionsLoaded = true;
2988         }
2989
2990         /**
2991          * Load restrictions from the page_restrictions table
2992          *
2993          * @param string $oldFashionedRestrictions Comma-separated list of page
2994          *   restrictions from page table (pre 1.10)
2995          */
2996         public function loadRestrictions( $oldFashionedRestrictions = null ) {
2997                 if ( $this->mRestrictionsLoaded ) {
2998                         return;
2999                 }
3000
3001                 $id = $this->getArticleID();
3002                 if ( $id ) {
3003                         $cache = ObjectCache::getMainWANInstance();
3004                         $rows = $cache->getWithSetCallback(
3005                                 // Page protections always leave a new null revision
3006                                 $cache->makeKey( 'page-restrictions', $id, $this->getLatestRevID() ),
3007                                 $cache::TTL_DAY,
3008                                 function ( $curValue, &$ttl, array &$setOpts ) {
3009                                         $dbr = wfGetDB( DB_REPLICA );
3010
3011                                         $setOpts += Database::getCacheSetOptions( $dbr );
3012
3013                                         return iterator_to_array(
3014                                                 $dbr->select(
3015                                                         'page_restrictions',
3016                                                         [ 'pr_type', 'pr_expiry', 'pr_level', 'pr_cascade' ],
3017                                                         [ 'pr_page' => $this->getArticleID() ],
3018                                                         __METHOD__
3019                                                 )
3020                                         );
3021                                 }
3022                         );
3023
3024                         $this->loadRestrictionsFromRows( $rows, $oldFashionedRestrictions );
3025                 } else {
3026                         $title_protection = $this->getTitleProtectionInternal();
3027
3028                         if ( $title_protection ) {
3029                                 $now = wfTimestampNow();
3030                                 $expiry = wfGetDB( DB_REPLICA )->decodeExpiry( $title_protection['expiry'] );
3031
3032                                 if ( !$expiry || $expiry > $now ) {
3033                                         // Apply the restrictions
3034                                         $this->mRestrictionsExpiry['create'] = $expiry;
3035                                         $this->mRestrictions['create'] =
3036                                                 explode( ',', trim( $title_protection['permission'] ) );
3037                                 } else { // Get rid of the old restrictions
3038                                         $this->mTitleProtection = false;
3039                                 }
3040                         } else {
3041                                 $this->mRestrictionsExpiry['create'] = 'infinity';
3042                         }
3043                         $this->mRestrictionsLoaded = true;
3044                 }
3045         }
3046
3047         /**
3048          * Flush the protection cache in this object and force reload from the database.
3049          * This is used when updating protection from WikiPage::doUpdateRestrictions().
3050          */
3051         public function flushRestrictions() {
3052                 $this->mRestrictionsLoaded = false;
3053                 $this->mTitleProtection = null;
3054         }
3055
3056         /**
3057          * Purge expired restrictions from the page_restrictions table
3058          *
3059          * This will purge no more than $wgUpdateRowsPerQuery page_restrictions rows
3060          */
3061         static function purgeExpiredRestrictions() {
3062                 if ( wfReadOnly() ) {
3063                         return;
3064                 }
3065
3066                 DeferredUpdates::addUpdate( new AtomicSectionUpdate(
3067                         wfGetDB( DB_MASTER ),
3068                         __METHOD__,
3069                         function ( IDatabase $dbw, $fname ) {
3070                                 $config = MediaWikiServices::getInstance()->getMainConfig();
3071                                 $ids = $dbw->selectFieldValues(
3072                                         'page_restrictions',
3073                                         'pr_id',
3074                                         [ 'pr_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ],
3075                                         $fname,
3076                                         [ 'LIMIT' => $config->get( 'UpdateRowsPerQuery' ) ] // T135470
3077                                 );
3078                                 if ( $ids ) {
3079                                         $dbw->delete( 'page_restrictions', [ 'pr_id' => $ids ], $fname );
3080                                 }
3081                         }
3082                 ) );
3083
3084                 DeferredUpdates::addUpdate( new AtomicSectionUpdate(
3085                         wfGetDB( DB_MASTER ),
3086                         __METHOD__,
3087                         function ( IDatabase $dbw, $fname ) {
3088                                 $dbw->delete(
3089                                         'protected_titles',
3090                                         [ 'pt_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ],
3091                                         $fname
3092                                 );
3093                         }
3094                 ) );
3095         }
3096
3097         /**
3098          * Does this have subpages?  (Warning, usually requires an extra DB query.)
3099          *
3100          * @return bool
3101          */
3102         public function hasSubpages() {
3103                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
3104                         # Duh
3105                         return false;
3106                 }
3107
3108                 # We dynamically add a member variable for the purpose of this method
3109                 # alone to cache the result.  There's no point in having it hanging
3110                 # around uninitialized in every Title object; therefore we only add it
3111                 # if needed and don't declare it statically.
3112                 if ( $this->mHasSubpages === null ) {
3113                         $this->mHasSubpages = false;
3114                         $subpages = $this->getSubpages( 1 );
3115                         if ( $subpages instanceof TitleArray ) {
3116                                 $this->mHasSubpages = (bool)$subpages->count();
3117                         }
3118                 }
3119
3120                 return $this->mHasSubpages;
3121         }
3122
3123         /**
3124          * Get all subpages of this page.
3125          *
3126          * @param int $limit Maximum number of subpages to fetch; -1 for no limit
3127          * @return TitleArray|array TitleArray, or empty array if this page's namespace
3128          *  doesn't allow subpages
3129          */
3130         public function getSubpages( $limit = -1 ) {
3131                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3132                         return [];
3133                 }
3134
3135                 $dbr = wfGetDB( DB_REPLICA );
3136                 $conds['page_namespace'] = $this->getNamespace();
3137                 $conds[] = 'page_title ' . $dbr->buildLike( $this->getDBkey() . '/', $dbr->anyString() );
3138                 $options = [];
3139                 if ( $limit > -1 ) {
3140                         $options['LIMIT'] = $limit;
3141                 }
3142                 $this->mSubpages = TitleArray::newFromResult(
3143                         $dbr->select( 'page',
3144                                 [ 'page_id', 'page_namespace', 'page_title', 'page_is_redirect' ],
3145                                 $conds,
3146                                 __METHOD__,
3147                                 $options
3148                         )
3149                 );
3150                 return $this->mSubpages;
3151         }
3152
3153         /**
3154          * Is there a version of this page in the deletion archive?
3155          *
3156          * @return int The number of archived revisions
3157          */
3158         public function isDeleted() {
3159                 if ( $this->getNamespace() < 0 ) {
3160                         $n = 0;
3161                 } else {
3162                         $dbr = wfGetDB( DB_REPLICA );
3163
3164                         $n = $dbr->selectField( 'archive', 'COUNT(*)',
3165                                 [ 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ],
3166                                 __METHOD__
3167                         );
3168                         if ( $this->getNamespace() == NS_FILE ) {
3169                                 $n += $dbr->selectField( 'filearchive', 'COUNT(*)',
3170                                         [ 'fa_name' => $this->getDBkey() ],
3171                                         __METHOD__
3172                                 );
3173                         }
3174                 }
3175                 return (int)$n;
3176         }
3177
3178         /**
3179          * Is there a version of this page in the deletion archive?
3180          *
3181          * @return bool
3182          */
3183         public function isDeletedQuick() {
3184                 if ( $this->getNamespace() < 0 ) {
3185                         return false;
3186                 }
3187                 $dbr = wfGetDB( DB_REPLICA );
3188                 $deleted = (bool)$dbr->selectField( 'archive', '1',
3189                         [ 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ],
3190                         __METHOD__
3191                 );
3192                 if ( !$deleted && $this->getNamespace() == NS_FILE ) {
3193                         $deleted = (bool)$dbr->selectField( 'filearchive', '1',
3194                                 [ 'fa_name' => $this->getDBkey() ],
3195                                 __METHOD__
3196                         );
3197                 }
3198                 return $deleted;
3199         }
3200
3201         /**
3202          * Get the article ID for this Title from the link cache,
3203          * adding it if necessary
3204          *
3205          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select
3206          *  for update
3207          * @return int The ID
3208          */
3209         public function getArticleID( $flags = 0 ) {
3210                 if ( $this->getNamespace() < 0 ) {
3211                         $this->mArticleID = 0;
3212                         return $this->mArticleID;
3213                 }
3214                 $linkCache = LinkCache::singleton();
3215                 if ( $flags & self::GAID_FOR_UPDATE ) {
3216                         $oldUpdate = $linkCache->forUpdate( true );
3217                         $linkCache->clearLink( $this );
3218                         $this->mArticleID = $linkCache->addLinkObj( $this );
3219                         $linkCache->forUpdate( $oldUpdate );
3220                 } else {
3221                         if ( -1 == $this->mArticleID ) {
3222                                 $this->mArticleID = $linkCache->addLinkObj( $this );
3223                         }
3224                 }
3225                 return $this->mArticleID;
3226         }
3227
3228         /**
3229          * Is this an article that is a redirect page?
3230          * Uses link cache, adding it if necessary
3231          *
3232          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3233          * @return bool
3234          */
3235         public function isRedirect( $flags = 0 ) {
3236                 if ( !is_null( $this->mRedirect ) ) {
3237                         return $this->mRedirect;
3238                 }
3239                 if ( !$this->getArticleID( $flags ) ) {
3240                         $this->mRedirect = false;
3241                         return $this->mRedirect;
3242                 }
3243
3244                 $linkCache = LinkCache::singleton();
3245                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3246                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'redirect' );
3247                 if ( $cached === null ) {
3248                         # Trust LinkCache's state over our own
3249                         # LinkCache is telling us that the page doesn't exist, despite there being cached
3250                         # data relating to an existing page in $this->mArticleID. Updaters should clear
3251                         # LinkCache as appropriate, or use $flags = Title::GAID_FOR_UPDATE. If that flag is
3252                         # set, then LinkCache will definitely be up to date here, since getArticleID() forces
3253                         # LinkCache to refresh its data from the master.
3254                         $this->mRedirect = false;
3255                         return $this->mRedirect;
3256                 }
3257
3258                 $this->mRedirect = (bool)$cached;
3259
3260                 return $this->mRedirect;
3261         }
3262
3263         /**
3264          * What is the length of this page?
3265          * Uses link cache, adding it if necessary
3266          *
3267          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3268          * @return int
3269          */
3270         public function getLength( $flags = 0 ) {
3271                 if ( $this->mLength != -1 ) {
3272                         return $this->mLength;
3273                 }
3274                 if ( !$this->getArticleID( $flags ) ) {
3275                         $this->mLength = 0;
3276                         return $this->mLength;
3277                 }
3278                 $linkCache = LinkCache::singleton();
3279                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3280                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'length' );
3281                 if ( $cached === null ) {
3282                         # Trust LinkCache's state over our own, as for isRedirect()
3283                         $this->mLength = 0;
3284                         return $this->mLength;
3285                 }
3286
3287                 $this->mLength = intval( $cached );
3288
3289                 return $this->mLength;
3290         }
3291
3292         /**
3293          * What is the page_latest field for this page?
3294          *
3295          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3296          * @return int Int or 0 if the page doesn't exist
3297          */
3298         public function getLatestRevID( $flags = 0 ) {
3299                 if ( !( $flags & Title::GAID_FOR_UPDATE ) && $this->mLatestID !== false ) {
3300                         return intval( $this->mLatestID );
3301                 }
3302                 if ( !$this->getArticleID( $flags ) ) {
3303                         $this->mLatestID = 0;
3304                         return $this->mLatestID;
3305                 }
3306                 $linkCache = LinkCache::singleton();
3307                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3308                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'revision' );
3309                 if ( $cached === null ) {
3310                         # Trust LinkCache's state over our own, as for isRedirect()
3311                         $this->mLatestID = 0;
3312                         return $this->mLatestID;
3313                 }
3314
3315                 $this->mLatestID = intval( $cached );
3316
3317                 return $this->mLatestID;
3318         }
3319
3320         /**
3321          * This clears some fields in this object, and clears any associated
3322          * keys in the "bad links" section of the link cache.
3323          *
3324          * - This is called from WikiPage::doEditContent() and WikiPage::insertOn() to allow
3325          * loading of the new page_id. It's also called from
3326          * WikiPage::doDeleteArticleReal()
3327          *
3328          * @param int $newid The new Article ID
3329          */
3330         public function resetArticleID( $newid ) {
3331                 $linkCache = LinkCache::singleton();
3332                 $linkCache->clearLink( $this );
3333
3334                 if ( $newid === false ) {
3335                         $this->mArticleID = -1;
3336                 } else {
3337                         $this->mArticleID = intval( $newid );
3338                 }
3339                 $this->mRestrictionsLoaded = false;
3340                 $this->mRestrictions = [];
3341                 $this->mOldRestrictions = false;
3342                 $this->mRedirect = null;
3343                 $this->mLength = -1;
3344                 $this->mLatestID = false;
3345                 $this->mContentModel = false;
3346                 $this->mEstimateRevisions = null;
3347                 $this->mPageLanguage = false;
3348                 $this->mDbPageLanguage = false;
3349                 $this->mIsBigDeletion = null;
3350         }
3351
3352         public static function clearCaches() {
3353                 $linkCache = LinkCache::singleton();
3354                 $linkCache->clear();
3355
3356                 $titleCache = self::getTitleCache();
3357                 $titleCache->clear();
3358         }
3359
3360         /**
3361          * Capitalize a text string for a title if it belongs to a namespace that capitalizes
3362          *
3363          * @param string $text Containing title to capitalize
3364          * @param int $ns Namespace index, defaults to NS_MAIN
3365          * @return string Containing capitalized title
3366          */
3367         public static function capitalize( $text, $ns = NS_MAIN ) {
3368                 global $wgContLang;
3369
3370                 if ( MWNamespace::isCapitalized( $ns ) ) {
3371                         return $wgContLang->ucfirst( $text );
3372                 } else {
3373                         return $text;
3374                 }
3375         }
3376
3377         /**
3378          * Secure and split - main initialisation function for this object
3379          *
3380          * Assumes that mDbkeyform has been set, and is urldecoded
3381          * and uses underscores, but not otherwise munged.  This function
3382          * removes illegal characters, splits off the interwiki and
3383          * namespace prefixes, sets the other forms, and canonicalizes
3384          * everything.
3385          *
3386          * @throws MalformedTitleException On invalid titles
3387          * @return bool True on success
3388          */
3389         private function secureAndSplit() {
3390                 # Initialisation
3391                 $this->mInterwiki = '';
3392                 $this->mFragment = '';
3393                 $this->mNamespace = $this->mDefaultNamespace; # Usually NS_MAIN
3394
3395                 $dbkey = $this->mDbkeyform;
3396
3397                 // @note: splitTitleString() is a temporary hack to allow MediaWikiTitleCodec to share
3398                 //        the parsing code with Title, while avoiding massive refactoring.
3399                 // @todo: get rid of secureAndSplit, refactor parsing code.
3400                 // @note: getTitleParser() returns a TitleParser implementation which does not have a
3401                 //        splitTitleString method, but the only implementation (MediaWikiTitleCodec) does
3402                 $titleCodec = MediaWikiServices::getInstance()->getTitleParser();
3403                 // MalformedTitleException can be thrown here
3404                 $parts = $titleCodec->splitTitleString( $dbkey, $this->getDefaultNamespace() );
3405
3406                 # Fill fields
3407                 $this->setFragment( '#' . $parts['fragment'] );
3408                 $this->mInterwiki = $parts['interwiki'];
3409                 $this->mLocalInterwiki = $parts['local_interwiki'];
3410                 $this->mNamespace = $parts['namespace'];
3411                 $this->mUserCaseDBKey = $parts['user_case_dbkey'];
3412
3413                 $this->mDbkeyform = $parts['dbkey'];
3414                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
3415                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
3416
3417                 # We already know that some pages won't be in the database!
3418                 if ( $this->isExternal() || $this->mNamespace == NS_SPECIAL ) {
3419                         $this->mArticleID = 0;
3420                 }
3421
3422                 return true;
3423         }
3424
3425         /**
3426          * Get an array of Title objects linking to this Title
3427          * Also stores the IDs in the link cache.
3428          *
3429          * WARNING: do not use this function on arbitrary user-supplied titles!
3430          * On heavily-used templates it will max out the memory.
3431          *
3432          * @param array $options May be FOR UPDATE
3433          * @param string $table Table name
3434          * @param string $prefix Fields prefix
3435          * @return Title[] Array of Title objects linking here
3436          */
3437         public function getLinksTo( $options = [], $table = 'pagelinks', $prefix = 'pl' ) {
3438                 if ( count( $options ) > 0 ) {
3439                         $db = wfGetDB( DB_MASTER );
3440                 } else {
3441                         $db = wfGetDB( DB_REPLICA );
3442                 }
3443
3444                 $res = $db->select(
3445                         [ 'page', $table ],
3446                         self::getSelectFields(),
3447                         [
3448                                 "{$prefix}_from=page_id",
3449                                 "{$prefix}_namespace" => $this->getNamespace(),
3450                                 "{$prefix}_title" => $this->getDBkey() ],
3451                         __METHOD__,
3452                         $options
3453                 );
3454
3455                 $retVal = [];
3456                 if ( $res->numRows() ) {
3457                         $linkCache = LinkCache::singleton();
3458                         foreach ( $res as $row ) {
3459                                 $titleObj = Title::makeTitle( $row->page_namespace, $row->page_title );
3460                                 if ( $titleObj ) {
3461                                         $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3462                                         $retVal[] = $titleObj;
3463                                 }
3464                         }
3465                 }
3466                 return $retVal;
3467         }
3468
3469         /**
3470          * Get an array of Title objects using this Title as a template
3471          * Also stores the IDs in the link cache.
3472          *
3473          * WARNING: do not use this function on arbitrary user-supplied titles!
3474          * On heavily-used templates it will max out the memory.
3475          *
3476          * @param array $options Query option to Database::select()
3477          * @return Title[] Array of Title the Title objects linking here
3478          */
3479         public function getTemplateLinksTo( $options = [] ) {
3480                 return $this->getLinksTo( $options, 'templatelinks', 'tl' );
3481         }
3482
3483         /**
3484          * Get an array of Title objects linked from this Title
3485          * Also stores the IDs in the link cache.
3486          *
3487          * WARNING: do not use this function on arbitrary user-supplied titles!
3488          * On heavily-used templates it will max out the memory.
3489          *
3490          * @param array $options Query option to Database::select()
3491          * @param string $table Table name
3492          * @param string $prefix Fields prefix
3493          * @return array Array of Title objects linking here
3494          */
3495         public function getLinksFrom( $options = [], $table = 'pagelinks', $prefix = 'pl' ) {
3496                 $id = $this->getArticleID();
3497
3498                 # If the page doesn't exist; there can't be any link from this page
3499                 if ( !$id ) {
3500                         return [];
3501                 }
3502
3503                 $db = wfGetDB( DB_REPLICA );
3504
3505                 $blNamespace = "{$prefix}_namespace";
3506                 $blTitle = "{$prefix}_title";
3507
3508                 $res = $db->select(
3509                         [ $table, 'page' ],
3510                         array_merge(
3511                                 [ $blNamespace, $blTitle ],
3512                                 WikiPage::selectFields()
3513                         ),
3514                         [ "{$prefix}_from" => $id ],
3515                         __METHOD__,
3516                         $options,
3517                         [ 'page' => [
3518                                 'LEFT JOIN',
3519                                 [ "page_namespace=$blNamespace", "page_title=$blTitle" ]
3520                         ] ]
3521                 );
3522
3523                 $retVal = [];
3524                 $linkCache = LinkCache::singleton();
3525                 foreach ( $res as $row ) {
3526                         if ( $row->page_id ) {
3527                                 $titleObj = Title::newFromRow( $row );
3528                         } else {
3529                                 $titleObj = Title::makeTitle( $row->$blNamespace, $row->$blTitle );
3530                                 $linkCache->addBadLinkObj( $titleObj );
3531                         }
3532                         $retVal[] = $titleObj;
3533                 }
3534
3535                 return $retVal;
3536         }
3537
3538         /**
3539          * Get an array of Title objects used on this Title as a template
3540          * Also stores the IDs in the link cache.
3541          *
3542          * WARNING: do not use this function on arbitrary user-supplied titles!
3543          * On heavily-used templates it will max out the memory.
3544          *
3545          * @param array $options May be FOR UPDATE
3546          * @return Title[] Array of Title the Title objects used here
3547          */
3548         public function getTemplateLinksFrom( $options = [] ) {
3549                 return $this->getLinksFrom( $options, 'templatelinks', 'tl' );
3550         }
3551
3552         /**
3553          * Get an array of Title objects referring to non-existent articles linked
3554          * from this page.
3555          *
3556          * @todo check if needed (used only in SpecialBrokenRedirects.php, and
3557          *   should use redirect table in this case).
3558          * @return Title[] Array of Title the Title objects
3559          */
3560         public function getBrokenLinksFrom() {
3561                 if ( $this->getArticleID() == 0 ) {
3562                         # All links from article ID 0 are false positives
3563                         return [];
3564                 }
3565
3566                 $dbr = wfGetDB( DB_REPLICA );
3567                 $res = $dbr->select(
3568                         [ 'page', 'pagelinks' ],
3569                         [ 'pl_namespace', 'pl_title' ],
3570                         [
3571                                 'pl_from' => $this->getArticleID(),
3572                                 'page_namespace IS NULL'
3573                         ],
3574                         __METHOD__, [],
3575                         [
3576                                 'page' => [
3577                                         'LEFT JOIN',
3578                                         [ 'pl_namespace=page_namespace', 'pl_title=page_title' ]
3579                                 ]
3580                         ]
3581                 );
3582
3583                 $retVal = [];
3584                 foreach ( $res as $row ) {
3585                         $retVal[] = Title::makeTitle( $row->pl_namespace, $row->pl_title );
3586                 }
3587                 return $retVal;
3588         }
3589
3590         /**
3591          * Get a list of URLs to purge from the CDN cache when this
3592          * page changes
3593          *
3594          * @return string[] Array of String the URLs
3595          */
3596         public function getCdnUrls() {
3597                 $urls = [
3598                         $this->getInternalURL(),
3599                         $this->getInternalURL( 'action=history' )
3600                 ];
3601
3602                 $pageLang = $this->getPageLanguage();
3603                 if ( $pageLang->hasVariants() ) {
3604                         $variants = $pageLang->getVariants();
3605                         foreach ( $variants as $vCode ) {
3606                                 $urls[] = $this->getInternalURL( $vCode );
3607                         }
3608                 }
3609
3610                 // If we are looking at a css/js user subpage, purge the action=raw.
3611                 if ( $this->isJsSubpage() ) {
3612                         $urls[] = $this->getInternalURL( 'action=raw&ctype=text/javascript' );
3613                 } elseif ( $this->isCssSubpage() ) {
3614                         $urls[] = $this->getInternalURL( 'action=raw&ctype=text/css' );
3615                 }
3616
3617                 Hooks::run( 'TitleSquidURLs', [ $this, &$urls ] );
3618                 return $urls;
3619         }
3620
3621         /**
3622          * @deprecated since 1.27 use getCdnUrls()
3623          */
3624         public function getSquidURLs() {
3625                 return $this->getCdnUrls();
3626         }
3627
3628         /**
3629          * Purge all applicable CDN URLs
3630          */
3631         public function purgeSquid() {
3632                 DeferredUpdates::addUpdate(
3633                         new CdnCacheUpdate( $this->getCdnUrls() ),
3634                         DeferredUpdates::PRESEND
3635                 );
3636         }
3637
3638         /**
3639          * Check whether a given move operation would be valid.
3640          * Returns true if ok, or a getUserPermissionsErrors()-like array otherwise
3641          *
3642          * @deprecated since 1.25, use MovePage's methods instead
3643          * @param Title $nt The new title
3644          * @param bool $auth Whether to check user permissions (uses $wgUser)
3645          * @param string $reason Is the log summary of the move, used for spam checking
3646          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3647          */
3648         public function isValidMoveOperation( &$nt, $auth = true, $reason = '' ) {
3649                 global $wgUser;
3650
3651                 if ( !( $nt instanceof Title ) ) {
3652                         // Normally we'd add this to $errors, but we'll get
3653                         // lots of syntax errors if $nt is not an object
3654                         return [ [ 'badtitletext' ] ];
3655                 }
3656
3657                 $mp = new MovePage( $this, $nt );
3658                 $errors = $mp->isValidMove()->getErrorsArray();
3659                 if ( $auth ) {
3660                         $errors = wfMergeErrorArrays(
3661                                 $errors,
3662                                 $mp->checkPermissions( $wgUser, $reason )->getErrorsArray()
3663                         );
3664                 }
3665
3666                 return $errors ?: true;
3667         }
3668
3669         /**
3670          * Check if the requested move target is a valid file move target
3671          * @todo move this to MovePage
3672          * @param Title $nt Target title
3673          * @return array List of errors
3674          */
3675         protected function validateFileMoveOperation( $nt ) {
3676                 global $wgUser;
3677
3678                 $errors = [];
3679
3680                 $destFile = wfLocalFile( $nt );
3681                 $destFile->load( File::READ_LATEST );
3682                 if ( !$wgUser->isAllowed( 'reupload-shared' )
3683                         && !$destFile->exists() && wfFindFile( $nt )
3684                 ) {
3685                         $errors[] = [ 'file-exists-sharedrepo' ];
3686                 }
3687
3688                 return $errors;
3689         }
3690
3691         /**
3692          * Move a title to a new location
3693          *
3694          * @deprecated since 1.25, use the MovePage class instead
3695          * @param Title $nt The new title
3696          * @param bool $auth Indicates whether $wgUser's permissions
3697          *  should be checked
3698          * @param string $reason The reason for the move
3699          * @param bool $createRedirect Whether to create a redirect from the old title to the new title.
3700          *  Ignored if the user doesn't have the suppressredirect right.
3701          * @param array $changeTags Applied to the entry in the move log and redirect page revision
3702          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3703          */
3704         public function moveTo( &$nt, $auth = true, $reason = '', $createRedirect = true,
3705                 array $changeTags = [] ) {
3706
3707                 global $wgUser;
3708                 $err = $this->isValidMoveOperation( $nt, $auth, $reason );
3709                 if ( is_array( $err ) ) {
3710                         // Auto-block user's IP if the account was "hard" blocked
3711                         $wgUser->spreadAnyEditBlock();
3712                         return $err;
3713                 }
3714                 // Check suppressredirect permission
3715                 if ( $auth && !$wgUser->isAllowed( 'suppressredirect' ) ) {
3716                         $createRedirect = true;
3717                 }
3718
3719                 $mp = new MovePage( $this, $nt );
3720                 $status = $mp->move( $wgUser, $reason, $createRedirect, $changeTags );
3721                 if ( $status->isOK() ) {
3722                         return true;
3723                 } else {
3724                         return $status->getErrorsArray();
3725                 }
3726         }
3727
3728         /**
3729          * Move this page's subpages to be subpages of $nt
3730          *
3731          * @param Title $nt Move target
3732          * @param bool $auth Whether $wgUser's permissions should be checked
3733          * @param string $reason The reason for the move
3734          * @param bool $createRedirect Whether to create redirects from the old subpages to
3735          *     the new ones Ignored if the user doesn't have the 'suppressredirect' right
3736          * @param array $changeTags Applied to the entry in the move log and redirect page revision
3737          * @return array Array with old page titles as keys, and strings (new page titles) or
3738          *     getUserPermissionsErrors()-like arrays (errors) as values, or a
3739          *     getUserPermissionsErrors()-like error array with numeric indices if
3740          *     no pages were moved
3741          */
3742         public function moveSubpages( $nt, $auth = true, $reason = '', $createRedirect = true,
3743                 array $changeTags = [] ) {
3744
3745                 global $wgMaximumMovedPages;
3746                 // Check permissions
3747                 if ( !$this->userCan( 'move-subpages' ) ) {
3748                         return [
3749                                 [ 'cant-move-subpages' ],
3750                         ];
3751                 }
3752                 // Do the source and target namespaces support subpages?
3753                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3754                         return [
3755                                 [ 'namespace-nosubpages', MWNamespace::getCanonicalName( $this->getNamespace() ) ],
3756                         ];
3757                 }
3758                 if ( !MWNamespace::hasSubpages( $nt->getNamespace() ) ) {
3759                         return [
3760                                 [ 'namespace-nosubpages', MWNamespace::getCanonicalName( $nt->getNamespace() ) ],
3761                         ];
3762                 }
3763
3764                 $subpages = $this->getSubpages( $wgMaximumMovedPages + 1 );
3765                 $retval = [];
3766                 $count = 0;
3767                 foreach ( $subpages as $oldSubpage ) {
3768                         $count++;
3769                         if ( $count > $wgMaximumMovedPages ) {
3770                                 $retval[$oldSubpage->getPrefixedText()] = [
3771                                         [ 'movepage-max-pages', $wgMaximumMovedPages ],
3772                                 ];
3773                                 break;
3774                         }
3775
3776                         // We don't know whether this function was called before
3777                         // or after moving the root page, so check both
3778                         // $this and $nt
3779                         if ( $oldSubpage->getArticleID() == $this->getArticleID()
3780                                 || $oldSubpage->getArticleID() == $nt->getArticleID()
3781                         ) {
3782                                 // When moving a page to a subpage of itself,
3783                                 // don't move it twice
3784                                 continue;
3785                         }
3786                         $newPageName = preg_replace(
3787                                         '#^' . preg_quote( $this->getDBkey(), '#' ) . '#',
3788                                         StringUtils::escapeRegexReplacement( $nt->getDBkey() ), # T23234
3789                                         $oldSubpage->getDBkey() );
3790                         if ( $oldSubpage->isTalkPage() ) {
3791                                 $newNs = $nt->getTalkPage()->getNamespace();
3792                         } else {
3793                                 $newNs = $nt->getSubjectPage()->getNamespace();
3794                         }
3795                         # T16385: we need makeTitleSafe because the new page names may
3796                         # be longer than 255 characters.
3797                         $newSubpage = Title::makeTitleSafe( $newNs, $newPageName );
3798
3799                         $success = $oldSubpage->moveTo( $newSubpage, $auth, $reason, $createRedirect, $changeTags );
3800                         if ( $success === true ) {
3801                                 $retval[$oldSubpage->getPrefixedText()] = $newSubpage->getPrefixedText();
3802                         } else {
3803                                 $retval[$oldSubpage->getPrefixedText()] = $success;
3804                         }
3805                 }
3806                 return $retval;
3807         }
3808
3809         /**
3810          * Checks if this page is just a one-rev redirect.
3811          * Adds lock, so don't use just for light purposes.
3812          *
3813          * @return bool
3814          */
3815         public function isSingleRevRedirect() {
3816                 global $wgContentHandlerUseDB;
3817
3818                 $dbw = wfGetDB( DB_MASTER );
3819
3820                 # Is it a redirect?
3821                 $fields = [ 'page_is_redirect', 'page_latest', 'page_id' ];
3822                 if ( $wgContentHandlerUseDB ) {
3823                         $fields[] = 'page_content_model';
3824                 }
3825
3826                 $row = $dbw->selectRow( 'page',
3827                         $fields,
3828                         $this->pageCond(),
3829                         __METHOD__,
3830                         [ 'FOR UPDATE' ]
3831                 );
3832                 # Cache some fields we may want
3833                 $this->mArticleID = $row ? intval( $row->page_id ) : 0;
3834                 $this->mRedirect = $row ? (bool)$row->page_is_redirect : false;
3835                 $this->mLatestID = $row ? intval( $row->page_latest ) : false;
3836                 $this->mContentModel = $row && isset( $row->page_content_model )
3837                         ? strval( $row->page_content_model )
3838                         : false;
3839
3840                 if ( !$this->mRedirect ) {
3841                         return false;
3842                 }
3843                 # Does the article have a history?
3844                 $row = $dbw->selectField( [ 'page', 'revision' ],
3845                         'rev_id',
3846                         [ 'page_namespace' => $this->getNamespace(),
3847                                 'page_title' => $this->getDBkey(),
3848                                 'page_id=rev_page',
3849                                 'page_latest != rev_id'
3850                         ],
3851                         __METHOD__,
3852                         [ 'FOR UPDATE' ]
3853                 );
3854                 # Return true if there was no history
3855                 return ( $row === false );
3856         }
3857
3858         /**
3859          * Checks if $this can be moved to a given Title
3860          * - Selects for update, so don't call it unless you mean business
3861          *
3862          * @deprecated since 1.25, use MovePage's methods instead
3863          * @param Title $nt The new title to check
3864          * @return bool
3865          */
3866         public function isValidMoveTarget( $nt ) {
3867                 # Is it an existing file?
3868                 if ( $nt->getNamespace() == NS_FILE ) {
3869                         $file = wfLocalFile( $nt );
3870                         $file->load( File::READ_LATEST );
3871                         if ( $file->exists() ) {
3872                                 wfDebug( __METHOD__ . ": file exists\n" );
3873                                 return false;
3874                         }
3875                 }
3876                 # Is it a redirect with no history?
3877                 if ( !$nt->isSingleRevRedirect() ) {
3878                         wfDebug( __METHOD__ . ": not a one-rev redirect\n" );
3879                         return false;
3880                 }
3881                 # Get the article text
3882                 $rev = Revision::newFromTitle( $nt, false, Revision::READ_LATEST );
3883                 if ( !is_object( $rev ) ) {
3884                         return false;
3885                 }
3886                 $content = $rev->getContent();
3887                 # Does the redirect point to the source?
3888                 # Or is it a broken self-redirect, usually caused by namespace collisions?
3889                 $redirTitle = $content ? $content->getRedirectTarget() : null;
3890
3891                 if ( $redirTitle ) {
3892                         if ( $redirTitle->getPrefixedDBkey() != $this->getPrefixedDBkey() &&
3893                                 $redirTitle->getPrefixedDBkey() != $nt->getPrefixedDBkey() ) {
3894                                 wfDebug( __METHOD__ . ": redirect points to other page\n" );
3895                                 return false;
3896                         } else {
3897                                 return true;
3898                         }
3899                 } else {
3900                         # Fail safe (not a redirect after all. strange.)
3901                         wfDebug( __METHOD__ . ": failsafe: database sais " . $nt->getPrefixedDBkey() .
3902                                                 " is a redirect, but it doesn't contain a valid redirect.\n" );
3903                         return false;
3904                 }
3905         }
3906
3907         /**
3908          * Get categories to which this Title belongs and return an array of
3909          * categories' names.
3910          *
3911          * @return array Array of parents in the form:
3912          *     $parent => $currentarticle
3913          */
3914         public function getParentCategories() {
3915                 global $wgContLang;
3916
3917                 $data = [];
3918
3919                 $titleKey = $this->getArticleID();
3920
3921                 if ( $titleKey === 0 ) {
3922                         return $data;
3923                 }
3924
3925                 $dbr = wfGetDB( DB_REPLICA );
3926
3927                 $res = $dbr->select(
3928                         'categorylinks',
3929                         'cl_to',
3930                         [ 'cl_from' => $titleKey ],
3931                         __METHOD__
3932                 );
3933
3934                 if ( $res->numRows() > 0 ) {
3935                         foreach ( $res as $row ) {
3936                                 // $data[] = Title::newFromText($wgContLang->getNsText ( NS_CATEGORY ).':'.$row->cl_to);
3937                                 $data[$wgContLang->getNsText( NS_CATEGORY ) . ':' . $row->cl_to] = $this->getFullText();
3938                         }
3939                 }
3940                 return $data;
3941         }
3942
3943         /**
3944          * Get a tree of parent categories
3945          *
3946          * @param array $children Array with the children in the keys, to check for circular refs
3947          * @return array Tree of parent categories
3948          */
3949         public function getParentCategoryTree( $children = [] ) {
3950                 $stack = [];
3951                 $parents = $this->getParentCategories();
3952
3953                 if ( $parents ) {
3954                         foreach ( $parents as $parent => $current ) {
3955                                 if ( array_key_exists( $parent, $children ) ) {
3956                                         # Circular reference
3957                                         $stack[$parent] = [];
3958                                 } else {
3959                                         $nt = Title::newFromText( $parent );
3960                                         if ( $nt ) {
3961                                                 $stack[$parent] = $nt->getParentCategoryTree( $children + [ $parent => 1 ] );
3962                                         }
3963                                 }
3964                         }
3965                 }
3966
3967                 return $stack;
3968         }
3969
3970         /**
3971          * Get an associative array for selecting this title from
3972          * the "page" table
3973          *
3974          * @return array Array suitable for the $where parameter of DB::select()
3975          */
3976         public function pageCond() {
3977                 if ( $this->mArticleID > 0 ) {
3978                         // PK avoids secondary lookups in InnoDB, shouldn't hurt other DBs
3979                         return [ 'page_id' => $this->mArticleID ];
3980                 } else {
3981                         return [ 'page_namespace' => $this->mNamespace, 'page_title' => $this->mDbkeyform ];
3982                 }
3983         }
3984
3985         /**
3986          * Get the revision ID of the previous revision
3987          *
3988          * @param int $revId Revision ID. Get the revision that was before this one.
3989          * @param int $flags Title::GAID_FOR_UPDATE
3990          * @return int|bool Old revision ID, or false if none exists
3991          */
3992         public function getPreviousRevisionID( $revId, $flags = 0 ) {
3993                 /* This function and getNextRevisionID have bad performance when
3994                    used on a page with many revisions on mysql. An explicit extended
3995                    primary key may help in some cases, if the PRIMARY KEY is banned:
3996                    T159319 */
3997                 if ( $flags & self::GAID_FOR_UPDATE ) {
3998                         $db = wfGetDB( DB_MASTER );
3999                 } else {
4000                         $db = wfGetDB( DB_REPLICA, 'contributions' );
4001                 }
4002                 $revId = $db->selectField( 'revision', 'rev_id',
4003                         [
4004                                 'rev_page' => $this->getArticleID( $flags ),
4005                                 'rev_id < ' . intval( $revId )
4006                         ],
4007                         __METHOD__,
4008                         [ 'ORDER BY' => 'rev_id DESC', 'IGNORE INDEX' => 'PRIMARY' ]
4009                 );
4010
4011                 if ( $revId === false ) {
4012                         return false;
4013                 } else {
4014                         return intval( $revId );
4015                 }
4016         }
4017
4018         /**
4019          * Get the revision ID of the next revision
4020          *
4021          * @param int $revId Revision ID. Get the revision that was after this one.
4022          * @param int $flags Title::GAID_FOR_UPDATE
4023          * @return int|bool Next revision ID, or false if none exists
4024          */
4025         public function getNextRevisionID( $revId, $flags = 0 ) {
4026                 if ( $flags & self::GAID_FOR_UPDATE ) {
4027                         $db = wfGetDB( DB_MASTER );
4028                 } else {
4029                         $db = wfGetDB( DB_REPLICA, 'contributions' );
4030                 }
4031                 $revId = $db->selectField( 'revision', 'rev_id',
4032                         [
4033                                 'rev_page' => $this->getArticleID( $flags ),
4034                                 'rev_id > ' . intval( $revId )
4035                         ],
4036                         __METHOD__,
4037                         [ 'ORDER BY' => 'rev_id', 'IGNORE INDEX' => 'PRIMARY' ]
4038                 );
4039
4040                 if ( $revId === false ) {
4041                         return false;
4042                 } else {
4043                         return intval( $revId );
4044                 }
4045         }
4046
4047         /**
4048          * Get the first revision of the page
4049          *
4050          * @param int $flags Title::GAID_FOR_UPDATE
4051          * @return Revision|null If page doesn't exist
4052          */
4053         public function getFirstRevision( $flags = 0 ) {
4054                 $pageId = $this->getArticleID( $flags );
4055                 if ( $pageId ) {
4056                         $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_REPLICA );
4057                         $row = $db->selectRow( 'revision', Revision::selectFields(),
4058                                 [ 'rev_page' => $pageId ],
4059                                 __METHOD__,
4060                                 [
4061                                         'ORDER BY' => 'rev_timestamp ASC',
4062                                         'IGNORE INDEX' => 'rev_timestamp'
4063                                 ]
4064                         );
4065                         if ( $row ) {
4066                                 return new Revision( $row );
4067                         }
4068                 }
4069                 return null;
4070         }
4071
4072         /**
4073          * Get the oldest revision timestamp of this page
4074          *
4075          * @param int $flags Title::GAID_FOR_UPDATE
4076          * @return string MW timestamp
4077          */
4078         public function getEarliestRevTime( $flags = 0 ) {
4079                 $rev = $this->getFirstRevision( $flags );
4080                 return $rev ? $rev->getTimestamp() : null;
4081         }
4082
4083         /**
4084          * Check if this is a new page
4085          *
4086          * @return bool
4087          */
4088         public function isNewPage() {
4089                 $dbr = wfGetDB( DB_REPLICA );
4090                 return (bool)$dbr->selectField( 'page', 'page_is_new', $this->pageCond(), __METHOD__ );
4091         }
4092
4093         /**
4094          * Check whether the number of revisions of this page surpasses $wgDeleteRevisionsLimit
4095          *
4096          * @return bool
4097          */
4098         public function isBigDeletion() {
4099                 global $wgDeleteRevisionsLimit;
4100
4101                 if ( !$wgDeleteRevisionsLimit ) {
4102                         return false;
4103                 }
4104
4105                 if ( $this->mIsBigDeletion === null ) {
4106                         $dbr = wfGetDB( DB_REPLICA );
4107
4108                         $revCount = $dbr->selectRowCount(
4109                                 'revision',
4110                                 '1',
4111                                 [ 'rev_page' => $this->getArticleID() ],
4112                                 __METHOD__,
4113                                 [ 'LIMIT' => $wgDeleteRevisionsLimit + 1 ]
4114                         );
4115
4116                         $this->mIsBigDeletion = $revCount > $wgDeleteRevisionsLimit;
4117                 }
4118
4119                 return $this->mIsBigDeletion;
4120         }
4121
4122         /**
4123          * Get the approximate revision count of this page.
4124          *
4125          * @return int
4126          */
4127         public function estimateRevisionCount() {
4128                 if ( !$this->exists() ) {
4129                         return 0;
4130                 }
4131
4132                 if ( $this->mEstimateRevisions === null ) {
4133                         $dbr = wfGetDB( DB_REPLICA );
4134                         $this->mEstimateRevisions = $dbr->estimateRowCount( 'revision', '*',
4135                                 [ 'rev_page' => $this->getArticleID() ], __METHOD__ );
4136                 }
4137
4138                 return $this->mEstimateRevisions;
4139         }
4140
4141         /**
4142          * Get the number of revisions between the given revision.
4143          * Used for diffs and other things that really need it.
4144          *
4145          * @param int|Revision $old Old revision or rev ID (first before range)
4146          * @param int|Revision $new New revision or rev ID (first after range)
4147          * @param int|null $max Limit of Revisions to count, will be incremented to detect truncations
4148          * @return int Number of revisions between these revisions.
4149          */
4150         public function countRevisionsBetween( $old, $new, $max = null ) {
4151                 if ( !( $old instanceof Revision ) ) {
4152                         $old = Revision::newFromTitle( $this, (int)$old );
4153                 }
4154                 if ( !( $new instanceof Revision ) ) {
4155                         $new = Revision::newFromTitle( $this, (int)$new );
4156                 }
4157                 if ( !$old || !$new ) {
4158                         return 0; // nothing to compare
4159                 }
4160                 $dbr = wfGetDB( DB_REPLICA );
4161                 $conds = [
4162                         'rev_page' => $this->getArticleID(),
4163                         'rev_timestamp > ' . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4164                         'rev_timestamp < ' . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4165                 ];
4166                 if ( $max !== null ) {
4167                         return $dbr->selectRowCount( 'revision', '1',
4168                                 $conds,
4169                                 __METHOD__,
4170                                 [ 'LIMIT' => $max + 1 ] // extra to detect truncation
4171                         );
4172                 } else {
4173                         return (int)$dbr->selectField( 'revision', 'count(*)', $conds, __METHOD__ );
4174                 }
4175         }
4176
4177         /**
4178          * Get the authors between the given revisions or revision IDs.
4179          * Used for diffs and other things that really need it.
4180          *
4181          * @since 1.23
4182          *
4183          * @param int|Revision $old Old revision or rev ID (first before range by default)
4184          * @param int|Revision $new New revision or rev ID (first after range by default)
4185          * @param int $limit Maximum number of authors
4186          * @param string|array $options (Optional): Single option, or an array of options:
4187          *     'include_old' Include $old in the range; $new is excluded.
4188          *     'include_new' Include $new in the range; $old is excluded.
4189          *     'include_both' Include both $old and $new in the range.
4190          *     Unknown option values are ignored.
4191          * @return array|null Names of revision authors in the range; null if not both revisions exist
4192          */
4193         public function getAuthorsBetween( $old, $new, $limit, $options = [] ) {
4194                 if ( !( $old instanceof Revision ) ) {
4195                         $old = Revision::newFromTitle( $this, (int)$old );
4196                 }
4197                 if ( !( $new instanceof Revision ) ) {
4198                         $new = Revision::newFromTitle( $this, (int)$new );
4199                 }
4200                 // XXX: what if Revision objects are passed in, but they don't refer to this title?
4201                 // Add $old->getPage() != $new->getPage() || $old->getPage() != $this->getArticleID()
4202                 // in the sanity check below?
4203                 if ( !$old || !$new ) {
4204                         return null; // nothing to compare
4205                 }
4206                 $authors = [];
4207                 $old_cmp = '>';
4208                 $new_cmp = '<';
4209                 $options = (array)$options;
4210                 if ( in_array( 'include_old', $options ) ) {
4211                         $old_cmp = '>=';
4212                 }
4213                 if ( in_array( 'include_new', $options ) ) {
4214                         $new_cmp = '<=';
4215                 }
4216                 if ( in_array( 'include_both', $options ) ) {
4217                         $old_cmp = '>=';
4218                         $new_cmp = '<=';
4219                 }
4220                 // No DB query needed if $old and $new are the same or successive revisions:
4221                 if ( $old->getId() === $new->getId() ) {
4222                         return ( $old_cmp === '>' && $new_cmp === '<' ) ?
4223                                 [] :
4224                                 [ $old->getUserText( Revision::RAW ) ];
4225                 } elseif ( $old->getId() === $new->getParentId() ) {
4226                         if ( $old_cmp === '>=' && $new_cmp === '<=' ) {
4227                                 $authors[] = $old->getUserText( Revision::RAW );
4228                                 if ( $old->getUserText( Revision::RAW ) != $new->getUserText( Revision::RAW ) ) {
4229                                         $authors[] = $new->getUserText( Revision::RAW );
4230                                 }
4231                         } elseif ( $old_cmp === '>=' ) {
4232                                 $authors[] = $old->getUserText( Revision::RAW );
4233                         } elseif ( $new_cmp === '<=' ) {
4234                                 $authors[] = $new->getUserText( Revision::RAW );
4235                         }
4236                         return $authors;
4237                 }
4238                 $dbr = wfGetDB( DB_REPLICA );
4239                 $res = $dbr->select( 'revision', 'DISTINCT rev_user_text',
4240                         [
4241                                 'rev_page' => $this->getArticleID(),
4242                                 "rev_timestamp $old_cmp " . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4243                                 "rev_timestamp $new_cmp " . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4244                         ], __METHOD__,
4245                         [ 'LIMIT' => $limit + 1 ] // add one so caller knows it was truncated
4246                 );
4247                 foreach ( $res as $row ) {
4248                         $authors[] = $row->rev_user_text;
4249                 }
4250                 return $authors;
4251         }
4252
4253         /**
4254          * Get the number of authors between the given revisions or revision IDs.
4255          * Used for diffs and other things that really need it.
4256          *
4257          * @param int|Revision $old Old revision or rev ID (first before range by default)
4258          * @param int|Revision $new New revision or rev ID (first after range by default)
4259          * @param int $limit Maximum number of authors
4260          * @param string|array $options (Optional): Single option, or an array of options:
4261          *     'include_old' Include $old in the range; $new is excluded.
4262          *     'include_new' Include $new in the range; $old is excluded.
4263          *     'include_both' Include both $old and $new in the range.
4264          *     Unknown option values are ignored.
4265          * @return int Number of revision authors in the range; zero if not both revisions exist
4266          */
4267         public function countAuthorsBetween( $old, $new, $limit, $options = [] ) {
4268                 $authors = $this->getAuthorsBetween( $old, $new, $limit, $options );
4269                 return $authors ? count( $authors ) : 0;
4270         }
4271
4272         /**
4273          * Compare with another title.
4274          *
4275          * @param Title $title
4276          * @return bool
4277          */
4278         public function equals( Title $title ) {
4279                 // Note: === is necessary for proper matching of number-like titles.
4280                 return $this->getInterwiki() === $title->getInterwiki()
4281                         && $this->getNamespace() == $title->getNamespace()
4282                         && $this->getDBkey() === $title->getDBkey();
4283         }
4284
4285         /**
4286          * Check if this title is a subpage of another title
4287          *
4288          * @param Title $title
4289          * @return bool
4290          */
4291         public function isSubpageOf( Title $title ) {
4292                 return $this->getInterwiki() === $title->getInterwiki()
4293                         && $this->getNamespace() == $title->getNamespace()
4294                         && strpos( $this->getDBkey(), $title->getDBkey() . '/' ) === 0;
4295         }
4296
4297         /**
4298          * Check if page exists.  For historical reasons, this function simply
4299          * checks for the existence of the title in the page table, and will
4300          * thus return false for interwiki links, special pages and the like.
4301          * If you want to know if a title can be meaningfully viewed, you should
4302          * probably call the isKnown() method instead.
4303          *
4304          * @param int $flags An optional bit field; may be Title::GAID_FOR_UPDATE to check
4305          *   from master/for update
4306          * @return bool
4307          */
4308         public function exists( $flags = 0 ) {
4309                 $exists = $this->getArticleID( $flags ) != 0;
4310                 Hooks::run( 'TitleExists', [ $this, &$exists ] );
4311                 return $exists;
4312         }
4313
4314         /**
4315          * Should links to this title be shown as potentially viewable (i.e. as
4316          * "bluelinks"), even if there's no record by this title in the page
4317          * table?
4318          *
4319          * This function is semi-deprecated for public use, as well as somewhat
4320          * misleadingly named.  You probably just want to call isKnown(), which
4321          * calls this function internally.
4322          *
4323          * (ISSUE: Most of these checks are cheap, but the file existence check
4324          * can potentially be quite expensive.  Including it here fixes a lot of
4325          * existing code, but we might want to add an optional parameter to skip
4326          * it and any other expensive checks.)
4327          *
4328          * @return bool
4329          */
4330         public function isAlwaysKnown() {
4331                 $isKnown = null;
4332
4333                 /**
4334                  * Allows overriding default behavior for determining if a page exists.
4335                  * If $isKnown is kept as null, regular checks happen. If it's
4336                  * a boolean, this value is returned by the isKnown method.
4337                  *
4338                  * @since 1.20
4339                  *
4340                  * @param Title $title
4341                  * @param bool|null $isKnown
4342                  */
4343                 Hooks::run( 'TitleIsAlwaysKnown', [ $this, &$isKnown ] );
4344
4345                 if ( !is_null( $isKnown ) ) {
4346                         return $isKnown;
4347                 }
4348
4349                 if ( $this->isExternal() ) {
4350                         return true;  // any interwiki link might be viewable, for all we know
4351                 }
4352
4353                 switch ( $this->mNamespace ) {
4354                         case NS_MEDIA:
4355                         case NS_FILE:
4356                                 // file exists, possibly in a foreign repo
4357                                 return (bool)wfFindFile( $this );
4358                         case NS_SPECIAL:
4359                                 // valid special page
4360                                 return SpecialPageFactory::exists( $this->getDBkey() );
4361                         case NS_MAIN:
4362                                 // selflink, possibly with fragment
4363                                 return $this->mDbkeyform == '';
4364                         case NS_MEDIAWIKI:
4365                                 // known system message
4366                                 return $this->hasSourceText() !== false;
4367                         default:
4368                                 return false;
4369                 }
4370         }
4371
4372         /**
4373          * Does this title refer to a page that can (or might) be meaningfully
4374          * viewed?  In particular, this function may be used to determine if
4375          * links to the title should be rendered as "bluelinks" (as opposed to
4376          * "redlinks" to non-existent pages).
4377          * Adding something else to this function will cause inconsistency
4378          * since LinkHolderArray calls isAlwaysKnown() and does its own
4379          * page existence check.
4380          *
4381          * @return bool
4382          */
4383         public function isKnown() {
4384                 return $this->isAlwaysKnown() || $this->exists();
4385         }
4386
4387         /**
4388          * Does this page have source text?
4389          *
4390          * @return bool
4391          */
4392         public function hasSourceText() {
4393                 if ( $this->exists() ) {
4394                         return true;
4395                 }
4396
4397                 if ( $this->mNamespace == NS_MEDIAWIKI ) {
4398                         // If the page doesn't exist but is a known system message, default
4399                         // message content will be displayed, same for language subpages-
4400                         // Use always content language to avoid loading hundreds of languages
4401                         // to get the link color.
4402                         global $wgContLang;
4403                         list( $name, ) = MessageCache::singleton()->figureMessage(
4404                                 $wgContLang->lcfirst( $this->getText() )
4405                         );
4406                         $message = wfMessage( $name )->inLanguage( $wgContLang )->useDatabase( false );
4407                         return $message->exists();
4408                 }
4409
4410                 return false;
4411         }
4412
4413         /**
4414          * Get the default message text or false if the message doesn't exist
4415          *
4416          * @return string|bool
4417          */
4418         public function getDefaultMessageText() {
4419                 global $wgContLang;
4420
4421                 if ( $this->getNamespace() != NS_MEDIAWIKI ) { // Just in case
4422                         return false;
4423                 }
4424
4425                 list( $name, $lang ) = MessageCache::singleton()->figureMessage(
4426                         $wgContLang->lcfirst( $this->getText() )
4427                 );
4428                 $message = wfMessage( $name )->inLanguage( $lang )->useDatabase( false );
4429
4430                 if ( $message->exists() ) {
4431                         return $message->plain();
4432                 } else {
4433                         return false;
4434                 }
4435         }
4436
4437         /**
4438          * Updates page_touched for this page; called from LinksUpdate.php
4439          *
4440          * @param string $purgeTime [optional] TS_MW timestamp
4441          * @return bool True if the update succeeded
4442          */
4443         public function invalidateCache( $purgeTime = null ) {
4444                 if ( wfReadOnly() ) {
4445                         return false;
4446                 } elseif ( $this->mArticleID === 0 ) {
4447                         return true; // avoid gap locking if we know it's not there
4448                 }
4449
4450                 $dbw = wfGetDB( DB_MASTER );
4451                 $dbw->onTransactionPreCommitOrIdle( function () {
4452                         ResourceLoaderWikiModule::invalidateModuleCache( $this, null, null, wfWikiID() );
4453                 } );
4454
4455                 $conds = $this->pageCond();
4456                 DeferredUpdates::addUpdate(
4457                         new AutoCommitUpdate(
4458                                 $dbw,
4459                                 __METHOD__,
4460                                 function ( IDatabase $dbw, $fname ) use ( $conds, $purgeTime ) {
4461                                         $dbTimestamp = $dbw->timestamp( $purgeTime ?: time() );
4462                                         $dbw->update(
4463                                                 'page',
4464                                                 [ 'page_touched' => $dbTimestamp ],
4465                                                 $conds + [ 'page_touched < ' . $dbw->addQuotes( $dbTimestamp ) ],
4466                                                 $fname
4467                                         );
4468                                         MediaWikiServices::getInstance()->getLinkCache()->invalidateTitle( $this );
4469                                 }
4470                         ),
4471                         DeferredUpdates::PRESEND
4472                 );
4473
4474                 return true;
4475         }
4476
4477         /**
4478          * Update page_touched timestamps and send CDN purge messages for
4479          * pages linking to this title. May be sent to the job queue depending
4480          * on the number of links. Typically called on create and delete.
4481          */
4482         public function touchLinks() {
4483                 DeferredUpdates::addUpdate( new HTMLCacheUpdate( $this, 'pagelinks' ) );
4484                 if ( $this->getNamespace() == NS_CATEGORY ) {
4485                         DeferredUpdates::addUpdate( new HTMLCacheUpdate( $this, 'categorylinks' ) );
4486                 }
4487         }
4488
4489         /**
4490          * Get the last touched timestamp
4491          *
4492          * @param IDatabase $db Optional db
4493          * @return string|false Last-touched timestamp
4494          */
4495         public function getTouched( $db = null ) {
4496                 if ( $db === null ) {
4497                         $db = wfGetDB( DB_REPLICA );
4498                 }
4499                 $touched = $db->selectField( 'page', 'page_touched', $this->pageCond(), __METHOD__ );
4500                 return $touched;
4501         }
4502
4503         /**
4504          * Get the timestamp when this page was updated since the user last saw it.
4505          *
4506          * @param User $user
4507          * @return string|null
4508          */
4509         public function getNotificationTimestamp( $user = null ) {
4510                 global $wgUser;
4511
4512                 // Assume current user if none given
4513                 if ( !$user ) {
4514                         $user = $wgUser;
4515                 }
4516                 // Check cache first
4517                 $uid = $user->getId();
4518                 if ( !$uid ) {
4519                         return false;
4520                 }
4521                 // avoid isset here, as it'll return false for null entries
4522                 if ( array_key_exists( $uid, $this->mNotificationTimestamp ) ) {
4523                         return $this->mNotificationTimestamp[$uid];
4524                 }
4525                 // Don't cache too much!
4526                 if ( count( $this->mNotificationTimestamp ) >= self::CACHE_MAX ) {
4527                         $this->mNotificationTimestamp = [];
4528                 }
4529
4530                 $store = MediaWikiServices::getInstance()->getWatchedItemStore();
4531                 $watchedItem = $store->getWatchedItem( $user, $this );
4532                 if ( $watchedItem ) {
4533                         $this->mNotificationTimestamp[$uid] = $watchedItem->getNotificationTimestamp();
4534                 } else {
4535                         $this->mNotificationTimestamp[$uid] = false;
4536                 }
4537
4538                 return $this->mNotificationTimestamp[$uid];
4539         }
4540
4541         /**
4542          * Generate strings used for xml 'id' names in monobook tabs
4543          *
4544          * @param string $prepend Defaults to 'nstab-'
4545          * @return string XML 'id' name
4546          */
4547         public function getNamespaceKey( $prepend = 'nstab-' ) {
4548                 global $wgContLang;
4549                 // Gets the subject namespace if this title
4550                 $namespace = MWNamespace::getSubject( $this->getNamespace() );
4551                 // Checks if canonical namespace name exists for namespace
4552                 if ( MWNamespace::exists( $this->getNamespace() ) ) {
4553                         // Uses canonical namespace name
4554                         $namespaceKey = MWNamespace::getCanonicalName( $namespace );
4555                 } else {
4556                         // Uses text of namespace
4557                         $namespaceKey = $this->getSubjectNsText();
4558                 }
4559                 // Makes namespace key lowercase
4560                 $namespaceKey = $wgContLang->lc( $namespaceKey );
4561                 // Uses main
4562                 if ( $namespaceKey == '' ) {
4563                         $namespaceKey = 'main';
4564                 }
4565                 // Changes file to image for backwards compatibility
4566                 if ( $namespaceKey == 'file' ) {
4567                         $namespaceKey = 'image';
4568                 }
4569                 return $prepend . $namespaceKey;
4570         }
4571
4572         /**
4573          * Get all extant redirects to this Title
4574          *
4575          * @param int|null $ns Single namespace to consider; null to consider all namespaces
4576          * @return Title[] Array of Title redirects to this title
4577          */
4578         public function getRedirectsHere( $ns = null ) {
4579                 $redirs = [];
4580
4581                 $dbr = wfGetDB( DB_REPLICA );
4582                 $where = [
4583                         'rd_namespace' => $this->getNamespace(),
4584                         'rd_title' => $this->getDBkey(),
4585                         'rd_from = page_id'
4586                 ];
4587                 if ( $this->isExternal() ) {
4588                         $where['rd_interwiki'] = $this->getInterwiki();
4589                 } else {
4590                         $where[] = 'rd_interwiki = ' . $dbr->addQuotes( '' ) . ' OR rd_interwiki IS NULL';
4591                 }
4592                 if ( !is_null( $ns ) ) {
4593                         $where['page_namespace'] = $ns;
4594                 }
4595
4596                 $res = $dbr->select(
4597                         [ 'redirect', 'page' ],
4598                         [ 'page_namespace', 'page_title' ],
4599                         $where,
4600                         __METHOD__
4601                 );
4602
4603                 foreach ( $res as $row ) {
4604                         $redirs[] = self::newFromRow( $row );
4605                 }
4606                 return $redirs;
4607         }
4608
4609         /**
4610          * Check if this Title is a valid redirect target
4611          *
4612          * @return bool
4613          */
4614         public function isValidRedirectTarget() {
4615                 global $wgInvalidRedirectTargets;
4616
4617                 if ( $this->isSpecialPage() ) {
4618                         // invalid redirect targets are stored in a global array, but explicitly disallow Userlogout here
4619                         if ( $this->isSpecial( 'Userlogout' ) ) {
4620                                 return false;
4621                         }
4622
4623                         foreach ( $wgInvalidRedirectTargets as $target ) {
4624                                 if ( $this->isSpecial( $target ) ) {
4625                                         return false;
4626                                 }
4627                         }
4628                 }
4629
4630                 return true;
4631         }
4632
4633         /**
4634          * Get a backlink cache object
4635          *
4636          * @return BacklinkCache
4637          */
4638         public function getBacklinkCache() {
4639                 return BacklinkCache::get( $this );
4640         }
4641
4642         /**
4643          * Whether the magic words __INDEX__ and __NOINDEX__ function for  this page.
4644          *
4645          * @return bool
4646          */
4647         public function canUseNoindex() {
4648                 global $wgExemptFromUserRobotsControl;
4649
4650                 $bannedNamespaces = is_null( $wgExemptFromUserRobotsControl )
4651                         ? MWNamespace::getContentNamespaces()
4652                         : $wgExemptFromUserRobotsControl;
4653
4654                 return !in_array( $this->mNamespace, $bannedNamespaces );
4655         }
4656
4657         /**
4658          * Returns the raw sort key to be used for categories, with the specified
4659          * prefix.  This will be fed to Collation::getSortKey() to get a
4660          * binary sortkey that can be used for actual sorting.
4661          *
4662          * @param string $prefix The prefix to be used, specified using
4663          *   {{defaultsort:}} or like [[Category:Foo|prefix]].  Empty for no
4664          *   prefix.
4665          * @return string
4666          */
4667         public function getCategorySortkey( $prefix = '' ) {
4668                 $unprefixed = $this->getText();
4669
4670                 // Anything that uses this hook should only depend
4671                 // on the Title object passed in, and should probably
4672                 // tell the users to run updateCollations.php --force
4673                 // in order to re-sort existing category relations.
4674                 Hooks::run( 'GetDefaultSortkey', [ $this, &$unprefixed ] );
4675                 if ( $prefix !== '' ) {
4676                         # Separate with a line feed, so the unprefixed part is only used as
4677                         # a tiebreaker when two pages have the exact same prefix.
4678                         # In UCA, tab is the only character that can sort above LF
4679                         # so we strip both of them from the original prefix.
4680                         $prefix = strtr( $prefix, "\n\t", '  ' );
4681                         return "$prefix\n$unprefixed";
4682                 }
4683                 return $unprefixed;
4684         }
4685
4686         /**
4687          * Returns the page language code saved in the database, if $wgPageLanguageUseDB is set
4688          * to true in LocalSettings.php, otherwise returns false. If there is no language saved in
4689          * the db, it will return NULL.
4690          *
4691          * @return string|null|bool
4692          */
4693         private function getDbPageLanguageCode() {
4694                 global $wgPageLanguageUseDB;
4695
4696                 // check, if the page language could be saved in the database, and if so and
4697                 // the value is not requested already, lookup the page language using LinkCache
4698                 if ( $wgPageLanguageUseDB && $this->mDbPageLanguage === false ) {
4699                         $linkCache = LinkCache::singleton();
4700                         $linkCache->addLinkObj( $this );
4701                         $this->mDbPageLanguage = $linkCache->getGoodLinkFieldObj( $this, 'lang' );
4702                 }
4703
4704                 return $this->mDbPageLanguage;
4705         }
4706
4707         /**
4708          * Get the language in which the content of this page is written in
4709          * wikitext. Defaults to $wgContLang, but in certain cases it can be
4710          * e.g. $wgLang (such as special pages, which are in the user language).
4711          *
4712          * @since 1.18
4713          * @return Language
4714          */
4715         public function getPageLanguage() {
4716                 global $wgLang, $wgLanguageCode;
4717                 if ( $this->isSpecialPage() ) {
4718                         // special pages are in the user language
4719                         return $wgLang;
4720                 }
4721
4722                 // Checking if DB language is set
4723                 $dbPageLanguage = $this->getDbPageLanguageCode();
4724                 if ( $dbPageLanguage ) {
4725                         return wfGetLangObj( $dbPageLanguage );
4726                 }
4727
4728                 if ( !$this->mPageLanguage || $this->mPageLanguage[1] !== $wgLanguageCode ) {
4729                         // Note that this may depend on user settings, so the cache should
4730                         // be only per-request.
4731                         // NOTE: ContentHandler::getPageLanguage() may need to load the
4732                         // content to determine the page language!
4733                         // Checking $wgLanguageCode hasn't changed for the benefit of unit
4734                         // tests.
4735                         $contentHandler = ContentHandler::getForTitle( $this );
4736                         $langObj = $contentHandler->getPageLanguage( $this );
4737                         $this->mPageLanguage = [ $langObj->getCode(), $wgLanguageCode ];
4738                 } else {
4739                         $langObj = wfGetLangObj( $this->mPageLanguage[0] );
4740                 }
4741
4742                 return $langObj;
4743         }
4744
4745         /**
4746          * Get the language in which the content of this page is written when
4747          * viewed by user. Defaults to $wgContLang, but in certain cases it can be
4748          * e.g. $wgLang (such as special pages, which are in the user language).
4749          *
4750          * @since 1.20
4751          * @return Language
4752          */
4753         public function getPageViewLanguage() {
4754                 global $wgLang;
4755
4756                 if ( $this->isSpecialPage() ) {
4757                         // If the user chooses a variant, the content is actually
4758                         // in a language whose code is the variant code.
4759                         $variant = $wgLang->getPreferredVariant();
4760                         if ( $wgLang->getCode() !== $variant ) {
4761                                 return Language::factory( $variant );
4762                         }
4763
4764                         return $wgLang;
4765                 }
4766
4767                 // Checking if DB language is set
4768                 $dbPageLanguage = $this->getDbPageLanguageCode();
4769                 if ( $dbPageLanguage ) {
4770                         $pageLang = wfGetLangObj( $dbPageLanguage );
4771                         $variant = $pageLang->getPreferredVariant();
4772                         if ( $pageLang->getCode() !== $variant ) {
4773                                 $pageLang = Language::factory( $variant );
4774                         }
4775
4776                         return $pageLang;
4777                 }
4778
4779                 // @note Can't be cached persistently, depends on user settings.
4780                 // @note ContentHandler::getPageViewLanguage() may need to load the
4781                 //   content to determine the page language!
4782                 $contentHandler = ContentHandler::getForTitle( $this );
4783                 $pageLang = $contentHandler->getPageViewLanguage( $this );
4784                 return $pageLang;
4785         }
4786
4787         /**
4788          * Get a list of rendered edit notices for this page.
4789          *
4790          * Array is keyed by the original message key, and values are rendered using parseAsBlock, so
4791          * they will already be wrapped in paragraphs.
4792          *
4793          * @since 1.21
4794          * @param int $oldid Revision ID that's being edited
4795          * @return array
4796          */
4797         public function getEditNotices( $oldid = 0 ) {
4798                 $notices = [];
4799
4800                 // Optional notice for the entire namespace
4801                 $editnotice_ns = 'editnotice-' . $this->getNamespace();
4802                 $msg = wfMessage( $editnotice_ns );
4803                 if ( $msg->exists() ) {
4804                         $html = $msg->parseAsBlock();
4805                         // Edit notices may have complex logic, but output nothing (T91715)
4806                         if ( trim( $html ) !== '' ) {
4807                                 $notices[$editnotice_ns] = Html::rawElement(
4808                                         'div',
4809                                         [ 'class' => [
4810                                                 'mw-editnotice',
4811                                                 'mw-editnotice-namespace',
4812                                                 Sanitizer::escapeClass( "mw-$editnotice_ns" )
4813                                         ] ],
4814                                         $html
4815                                 );
4816                         }
4817                 }
4818
4819                 if ( MWNamespace::hasSubpages( $this->getNamespace() ) ) {
4820                         // Optional notice for page itself and any parent page
4821                         $parts = explode( '/', $this->getDBkey() );
4822                         $editnotice_base = $editnotice_ns;
4823                         while ( count( $parts ) > 0 ) {
4824                                 $editnotice_base .= '-' . array_shift( $parts );
4825                                 $msg = wfMessage( $editnotice_base );
4826                                 if ( $msg->exists() ) {
4827                                         $html = $msg->parseAsBlock();
4828                                         if ( trim( $html ) !== '' ) {
4829                                                 $notices[$editnotice_base] = Html::rawElement(
4830                                                         'div',
4831                                                         [ 'class' => [
4832                                                                 'mw-editnotice',
4833                                                                 'mw-editnotice-base',
4834                                                                 Sanitizer::escapeClass( "mw-$editnotice_base" )
4835                                                         ] ],
4836                                                         $html
4837                                                 );
4838                                         }
4839                                 }
4840                         }
4841                 } else {
4842                         // Even if there are no subpages in namespace, we still don't want "/" in MediaWiki message keys
4843                         $editnoticeText = $editnotice_ns . '-' . strtr( $this->getDBkey(), '/', '-' );
4844                         $msg = wfMessage( $editnoticeText );
4845                         if ( $msg->exists() ) {
4846                                 $html = $msg->parseAsBlock();
4847                                 if ( trim( $html ) !== '' ) {
4848                                         $notices[$editnoticeText] = Html::rawElement(
4849                                                 'div',
4850                                                 [ 'class' => [
4851                                                         'mw-editnotice',
4852                                                         'mw-editnotice-page',
4853                                                         Sanitizer::escapeClass( "mw-$editnoticeText" )
4854                                                 ] ],
4855                                                 $html
4856                                         );
4857                                 }
4858                         }
4859                 }
4860
4861                 Hooks::run( 'TitleGetEditNotices', [ $this, $oldid, &$notices ] );
4862                 return $notices;
4863         }
4864
4865         /**
4866          * @return array
4867          */
4868         public function __sleep() {
4869                 return [
4870                         'mNamespace',
4871                         'mDbkeyform',
4872                         'mFragment',
4873                         'mInterwiki',
4874                         'mLocalInterwiki',
4875                         'mUserCaseDBKey',
4876                         'mDefaultNamespace',
4877                 ];
4878         }
4879
4880         public function __wakeup() {
4881                 $this->mArticleID = ( $this->mNamespace >= 0 ) ? -1 : 0;
4882                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
4883                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
4884         }
4885
4886 }