includes/Title.php

   1 <?php
   2 /**
   3  * Representation of a title within %MediaWiki.
   4  *
   5  * See title.txt
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License along
  18  * with this program; if not, write to the Free Software Foundation, Inc.,
  19  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  20  * http://www.gnu.org/copyleft/gpl.html
  21  *
  22  * @file
  23  */
  24
  25 use Wikimedia\Rdbms\Database;
  26 use Wikimedia\Rdbms\IDatabase;
  27 use MediaWiki\Linker\LinkTarget;
  28 use MediaWiki\Interwiki\InterwikiLookup;
  29 use MediaWiki\MediaWikiServices;
  30
  31 /**
  32  * Represents a title within MediaWiki.
  33  * Optionally may contain an interwiki designation or namespace.
  34  * @note This class can fetch various kinds of data from the database;
  35  *       however, it does so inefficiently.
  36  * @note Consider using a TitleValue object instead. TitleValue is more lightweight
  37  *       and does not rely on global state or the database.
  38  */
  39 class Title implements LinkTarget {
  40         /** @var HashBagOStuff */
  41         static private $titleCache = null;
  42
  43         /**
  44          * Title::newFromText maintains a cache to avoid expensive re-normalization of
  45          * commonly used titles. On a batch operation this can become a memory leak
  46          * if not bounded. After hitting this many titles reset the cache.
  47          */
  48         const CACHE_MAX = 1000;
  49
  50         /**
  51          * Used to be GAID_FOR_UPDATE define. Used with getArticleID() and friends
  52          * to use the master DB
  53          */
  54         const GAID_FOR_UPDATE = 1;
  55
  56         /**
  57          * @name Private member variables
  58          * Please use the accessor functions instead.
  59          * @private
  60          */
  61         // @{
  62
  63         /** @var string Text form (spaces not underscores) of the main part */
  64         public $mTextform = '';
  65
  66         /** @var string URL-encoded form of the main part */
  67         public $mUrlform = '';
  68
  69         /** @var string Main part with underscores */
  70         public $mDbkeyform = '';
  71
  72         /** @var string Database key with the initial letter in the case specified by the user */
  73         protected $mUserCaseDBKey;
  74
  75         /** @var int Namespace index, i.e. one of the NS_xxxx constants */
  76         public $mNamespace = NS_MAIN;
  77
  78         /** @var string Interwiki prefix */
  79         public $mInterwiki = '';
  80
  81         /** @var bool Was this Title created from a string with a local interwiki prefix? */
  82         private $mLocalInterwiki = false;
  83
  84         /** @var string Title fragment (i.e. the bit after the #) */
  85         public $mFragment = '';
  86
  87         /** @var int Article ID, fetched from the link cache on demand */
  88         public $mArticleID = -1;
  89
  90         /** @var bool|int ID of most recent revision */
  91         protected $mLatestID = false;
  92
  93         /**
  94          * @var bool|string ID of the page's content model, i.e. one of the
  95          *   CONTENT_MODEL_XXX constants
  96          */
  97         private $mContentModel = false;
  98
  99         /**
 100          * @var bool If a content model was forced via setContentModel()
 101          *   this will be true to avoid having other code paths reset it
 102          */
 103         private $mForcedContentModel = false;
 104
 105         /** @var int Estimated number of revisions; null of not loaded */
 106         private $mEstimateRevisions;
 107
 108         /** @var array Array of groups allowed to edit this article */
 109         public $mRestrictions = [];
 110
 111         /**
 112          * @var string|bool Comma-separated set of permission keys
 113          * indicating who can move or edit the page from the page table, (pre 1.10) rows.
 114          * Edit and move sections are separated by a colon
 115          * Example: "edit=autoconfirmed,sysop:move=sysop"
 116          */
 117         protected $mOldRestrictions = false;
 118
 119         /** @var bool Cascade restrictions on this page to included templates and images? */
 120         public $mCascadeRestriction;
 121
 122         /** Caching the results of getCascadeProtectionSources */
 123         public $mCascadingRestrictions;
 124
 125         /** @var array When do the restrictions on this page expire? */
 126         protected $mRestrictionsExpiry = [];
 127
 128         /** @var bool Are cascading restrictions in effect on this page? */
 129         protected $mHasCascadingRestrictions;
 130
 131         /** @var array Where are the cascading restrictions coming from on this page? */
 132         public $mCascadeSources;
 133
 134         /** @var bool Boolean for initialisation on demand */
 135         public $mRestrictionsLoaded = false;
 136
 137         /** @var string Text form including namespace/interwiki, initialised on demand */
 138         protected $mPrefixedText = null;
 139
 140         /** @var mixed Cached value for getTitleProtection (create protection) */
 141         public $mTitleProtection;
 142
 143         /**
 144          * @var int Namespace index when there is no namespace. Don't change the
 145          *   following default, NS_MAIN is hardcoded in several places. See T2696.
 146          *   Zero except in {{transclusion}} tags.
 147          */
 148         public $mDefaultNamespace = NS_MAIN;
 149
 150         /** @var int The page length, 0 for special pages */
 151         protected $mLength = -1;
 152
 153         /** @var null Is the article at this title a redirect? */
 154         public $mRedirect = null;
 155
 156         /** @var array Associative array of user ID -> timestamp/false */
 157         private $mNotificationTimestamp = [];
 158
 159         /** @var bool Whether a page has any subpages */
 160         private $mHasSubpages;
 161
 162         /** @var bool The (string) language code of the page's language and content code. */
 163         private $mPageLanguage = false;
 164
 165         /** @var string|bool|null The page language code from the database, null if not saved in
 166          * the database or false if not loaded, yet. */
 167         private $mDbPageLanguage = false;
 168
 169         /** @var TitleValue A corresponding TitleValue object */
 170         private $mTitleValue = null;
 171
 172         /** @var bool Would deleting this page be a big deletion? */
 173         private $mIsBigDeletion = null;
 174         // @}
 175
 176         /**
 177          * B/C kludge: provide a TitleParser for use by Title.
 178          * Ideally, Title would have no methods that need this.
 179          * Avoid usage of this singleton by using TitleValue
 180          * and the associated services when possible.
 181          *
 182          * @return TitleFormatter
 183          */
 184         private static function getTitleFormatter() {
 185                 return MediaWikiServices::getInstance()->getTitleFormatter();
 186         }
 187
 188         /**
 189          * B/C kludge: provide an InterwikiLookup for use by Title.
 190          * Ideally, Title would have no methods that need this.
 191          * Avoid usage of this singleton by using TitleValue
 192          * and the associated services when possible.
 193          *
 194          * @return InterwikiLookup
 195          */
 196         private static function getInterwikiLookup() {
 197                 return MediaWikiServices::getInstance()->getInterwikiLookup();
 198         }
 199
 200         /**
 201          * @access protected
 202          */
 203         function __construct() {
 204         }
 205
 206         /**
 207          * Create a new Title from a prefixed DB key
 208          *
 209          * @param string $key The database key, which has underscores
 210          *      instead of spaces, possibly including namespace and
 211          *      interwiki prefixes
 212          * @return Title|null Title, or null on an error
 213          */
 214         public static function newFromDBkey( $key ) {
 215                 $t = new Title();
 216                 $t->mDbkeyform = $key;
 217
 218                 try {
 219                         $t->secureAndSplit();
 220                         return $t;
 221                 } catch ( MalformedTitleException $ex ) {
 222                         return null;
 223                 }
 224         }
 225
 226         /**
 227          * Create a new Title from a TitleValue
 228          *
 229          * @param TitleValue $titleValue Assumed to be safe.
 230          *
 231          * @return Title
 232          */
 233         public static function newFromTitleValue( TitleValue $titleValue ) {
 234                 return self::newFromLinkTarget( $titleValue );
 235         }
 236
 237         /**
 238          * Create a new Title from a LinkTarget
 239          *
 240          * @param LinkTarget $linkTarget Assumed to be safe.
 241          *
 242          * @return Title
 243          */
 244         public static function newFromLinkTarget( LinkTarget $linkTarget ) {
 245                 if ( $linkTarget instanceof Title ) {
 246                         // Special case if it's already a Title object
 247                         return $linkTarget;
 248                 }
 249                 return self::makeTitle(
 250                         $linkTarget->getNamespace(),
 251                         $linkTarget->getText(),
 252                         $linkTarget->getFragment(),
 253                         $linkTarget->getInterwiki()
 254                 );
 255         }
 256
 257         /**
 258          * Create a new Title from text, such as what one would find in a link. De-
 259          * codes any HTML entities in the text.
 260          *
 261          * Title objects returned by this method are guaranteed to be valid, and
 262          * thus return true from the isValid() method.
 263          *
 264          * @param string|int|null $text The link text; spaces, prefixes, and an
 265          *   initial ':' indicating the main namespace are accepted.
 266          * @param int $defaultNamespace The namespace to use if none is specified
 267          *   by a prefix.  If you want to force a specific namespace even if
 268          *   $text might begin with a namespace prefix, use makeTitle() or
 269          *   makeTitleSafe().
 270          * @throws InvalidArgumentException
 271          * @return Title|null Title or null on an error.
 272          */
 273         public static function newFromText( $text, $defaultNamespace = NS_MAIN ) {
 274                 // DWIM: Integers can be passed in here when page titles are used as array keys.
 275                 if ( $text !== null && !is_string( $text ) && !is_int( $text ) ) {
 276                         throw new InvalidArgumentException( '$text must be a string.' );
 277                 }
 278                 if ( $text === null ) {
 279                         return null;
 280                 }
 281
 282                 try {
 283                         return self::newFromTextThrow( strval( $text ), $defaultNamespace );
 284                 } catch ( MalformedTitleException $ex ) {
 285                         return null;
 286                 }
 287         }
 288
 289         /**
 290          * Like Title::newFromText(), but throws MalformedTitleException when the title is invalid,
 291          * rather than returning null.
 292          *
 293          * The exception subclasses encode detailed information about why the title is invalid.
 294          *
 295          * Title objects returned by this method are guaranteed to be valid, and
 296          * thus return true from the isValid() method.
 297          *
 298          * @see Title::newFromText
 299          *
 300          * @since 1.25
 301          * @param string $text Title text to check
 302          * @param int $defaultNamespace
 303          * @throws MalformedTitleException If the title is invalid
 304          * @return Title
 305          */
 306         public static function newFromTextThrow( $text, $defaultNamespace = NS_MAIN ) {
 307                 if ( is_object( $text ) ) {
 308                         throw new MWException( '$text must be a string, given an object' );
 309                 }
 310
 311                 $titleCache = self::getTitleCache();
 312
 313                 // Wiki pages often contain multiple links to the same page.
 314                 // Title normalization and parsing can become expensive on pages with many
 315                 // links, so we can save a little time by caching them.
 316                 // In theory these are value objects and won't get changed...
 317                 if ( $defaultNamespace == NS_MAIN ) {
 318                         $t = $titleCache->get( $text );
 319                         if ( $t ) {
 320                                 return $t;
 321                         }
 322                 }
 323
 324                 // Convert things like &eacute; &#257; or &#x3017; into normalized (T16952) text
 325                 $filteredText = Sanitizer::decodeCharReferencesAndNormalize( $text );
 326
 327                 $t = new Title();
 328                 $t->mDbkeyform = strtr( $filteredText, ' ', '_' );
 329                 $t->mDefaultNamespace = intval( $defaultNamespace );
 330
 331                 $t->secureAndSplit();
 332                 if ( $defaultNamespace == NS_MAIN ) {
 333                         $titleCache->set( $text, $t );
 334                 }
 335                 return $t;
 336         }
 337
 338         /**
 339          * THIS IS NOT THE FUNCTION YOU WANT. Use Title::newFromText().
 340          *
 341          * Example of wrong and broken code:
 342          * $title = Title::newFromURL( $wgRequest->getVal( 'title' ) );
 343          *
 344          * Example of right code:
 345          * $title = Title::newFromText( $wgRequest->getVal( 'title' ) );
 346          *
 347          * Create a new Title from URL-encoded text. Ensures that
 348          * the given title's length does not exceed the maximum.
 349          *
 350          * @param string $url The title, as might be taken from a URL
 351          * @return Title|null The new object, or null on an error
 352          */
 353         public static function newFromURL( $url ) {
 354                 $t = new Title();
 355
 356                 # For compatibility with old buggy URLs. "+" is usually not valid in titles,
 357                 # but some URLs used it as a space replacement and they still come
 358                 # from some external search tools.
 359                 if ( strpos( self::legalChars(), '+' ) === false ) {
 360                         $url = strtr( $url, '+', ' ' );
 361                 }
 362
 363                 $t->mDbkeyform = strtr( $url, ' ', '_' );
 364
 365                 try {
 366                         $t->secureAndSplit();
 367                         return $t;
 368                 } catch ( MalformedTitleException $ex ) {
 369                         return null;
 370                 }
 371         }
 372
 373         /**
 374          * @return HashBagOStuff
 375          */
 376         private static function getTitleCache() {
 377                 if ( self::$titleCache == null ) {
 378                         self::$titleCache = new HashBagOStuff( [ 'maxKeys' => self::CACHE_MAX ] );
 379                 }
 380                 return self::$titleCache;
 381         }
 382
 383         /**
 384          * Returns a list of fields that are to be selected for initializing Title
 385          * objects or LinkCache entries. Uses $wgContentHandlerUseDB to determine
 386          * whether to include page_content_model.
 387          *
 388          * @return array
 389          */
 390         protected static function getSelectFields() {
 391                 global $wgContentHandlerUseDB, $wgPageLanguageUseDB;
 392
 393                 $fields = [
 394                         'page_namespace', 'page_title', 'page_id',
 395                         'page_len', 'page_is_redirect', 'page_latest',
 396                 ];
 397
 398                 if ( $wgContentHandlerUseDB ) {
 399                         $fields[] = 'page_content_model';
 400                 }
 401
 402                 if ( $wgPageLanguageUseDB ) {
 403                         $fields[] = 'page_lang';
 404                 }
 405
 406                 return $fields;
 407         }
 408
 409         /**
 410          * Create a new Title from an article ID
 411          *
 412          * @param int $id The page_id corresponding to the Title to create
 413          * @param int $flags Use Title::GAID_FOR_UPDATE to use master
 414          * @return Title|null The new object, or null on an error
 415          */
 416         public static function newFromID( $id, $flags = 0 ) {
 417                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_REPLICA );
 418                 $row = $db->selectRow(
 419                         'page',
 420                         self::getSelectFields(),
 421                         [ 'page_id' => $id ],
 422                         __METHOD__
 423                 );
 424                 if ( $row !== false ) {
 425                         $title = self::newFromRow( $row );
 426                 } else {
 427                         $title = null;
 428                 }
 429                 return $title;
 430         }
 431
 432         /**
 433          * Make an array of titles from an array of IDs
 434          *
 435          * @param int[] $ids Array of IDs
 436          * @return Title[] Array of Titles
 437          */
 438         public static function newFromIDs( $ids ) {
 439                 if ( !count( $ids ) ) {
 440                         return [];
 441                 }
 442                 $dbr = wfGetDB( DB_REPLICA );
 443
 444                 $res = $dbr->select(
 445                         'page',
 446                         self::getSelectFields(),
 447                         [ 'page_id' => $ids ],
 448                         __METHOD__
 449                 );
 450
 451                 $titles = [];
 452                 foreach ( $res as $row ) {
 453                         $titles[] = self::newFromRow( $row );
 454                 }
 455                 return $titles;
 456         }
 457
 458         /**
 459          * Make a Title object from a DB row
 460          *
 461          * @param stdClass $row Object database row (needs at least page_title,page_namespace)
 462          * @return Title Corresponding Title
 463          */
 464         public static function newFromRow( $row ) {
 465                 $t = self::makeTitle( $row->page_namespace, $row->page_title );
 466                 $t->loadFromRow( $row );
 467                 return $t;
 468         }
 469
 470         /**
 471          * Load Title object fields from a DB row.
 472          * If false is given, the title will be treated as non-existing.
 473          *
 474          * @param stdClass|bool $row Database row
 475          */
 476         public function loadFromRow( $row ) {
 477                 if ( $row ) { // page found
 478                         if ( isset( $row->page_id ) ) {
 479                                 $this->mArticleID = (int)$row->page_id;
 480                         }
 481                         if ( isset( $row->page_len ) ) {
 482                                 $this->mLength = (int)$row->page_len;
 483                         }
 484                         if ( isset( $row->page_is_redirect ) ) {
 485                                 $this->mRedirect = (bool)$row->page_is_redirect;
 486                         }
 487                         if ( isset( $row->page_latest ) ) {
 488                                 $this->mLatestID = (int)$row->page_latest;
 489                         }
 490                         if ( !$this->mForcedContentModel && isset( $row->page_content_model ) ) {
 491                                 $this->mContentModel = strval( $row->page_content_model );
 492                         } elseif ( !$this->mForcedContentModel ) {
 493                                 $this->mContentModel = false; # initialized lazily in getContentModel()
 494                         }
 495                         if ( isset( $row->page_lang ) ) {
 496                                 $this->mDbPageLanguage = (string)$row->page_lang;
 497                         }
 498                         if ( isset( $row->page_restrictions ) ) {
 499                                 $this->mOldRestrictions = $row->page_restrictions;
 500                         }
 501                 } else { // page not found
 502                         $this->mArticleID = 0;
 503                         $this->mLength = 0;
 504                         $this->mRedirect = false;
 505                         $this->mLatestID = 0;
 506                         if ( !$this->mForcedContentModel ) {
 507                                 $this->mContentModel = false; # initialized lazily in getContentModel()
 508                         }
 509                 }
 510         }
 511
 512         /**
 513          * Create a new Title from a namespace index and a DB key.
 514          *
 515          * It's assumed that $ns and $title are safe, for instance when
 516          * they came directly from the database or a special page name,
 517          * not from user input.
 518          *
 519          * No validation is applied. For convenience, spaces are normalized
 520          * to underscores, so that e.g. user_text fields can be used directly.
 521          *
 522          * @note This method may return Title objects that are "invalid"
 523          * according to the isValid() method. This is usually caused by
 524          * configuration changes: e.g. a namespace that was once defined is
 525          * no longer configured, or a character that was once allowed in
 526          * titles is now forbidden.
 527          *
 528          * @param int $ns The namespace of the article
 529          * @param string $title The unprefixed database key form
 530          * @param string $fragment The link fragment (after the "#")
 531          * @param string $interwiki The interwiki prefix
 532          * @return Title The new object
 533          */
 534         public static function makeTitle( $ns, $title, $fragment = '', $interwiki = '' ) {
 535                 $t = new Title();
 536                 $t->mInterwiki = $interwiki;
 537                 $t->mFragment = $fragment;
 538                 $t->mNamespace = $ns = intval( $ns );
 539                 $t->mDbkeyform = strtr( $title, ' ', '_' );
 540                 $t->mArticleID = ( $ns >= 0 ) ? -1 : 0;
 541                 $t->mUrlform = wfUrlencode( $t->mDbkeyform );
 542                 $t->mTextform = strtr( $title, '_', ' ' );
 543                 $t->mContentModel = false; # initialized lazily in getContentModel()
 544                 return $t;
 545         }
 546
 547         /**
 548          * Create a new Title from a namespace index and a DB key.
 549          * The parameters will be checked for validity, which is a bit slower
 550          * than makeTitle() but safer for user-provided data.
 551          *
 552          * Title objects returned by makeTitleSafe() are guaranteed to be valid,
 553          * that is, they return true from the isValid() method. If no valid Title
 554          * can be constructed from the input, this method returns null.
 555          *
 556          * @param int $ns The namespace of the article
 557          * @param string $title Database key form
 558          * @param string $fragment The link fragment (after the "#")
 559          * @param string $interwiki Interwiki prefix
 560          * @return Title|null The new object, or null on an error
 561          */
 562         public static function makeTitleSafe( $ns, $title, $fragment = '', $interwiki = '' ) {
 563                 // NOTE: ideally, this would just call makeTitle() and then isValid(),
 564                 // but presently, that means more overhead on a potential performance hotspot.
 565
 566                 if ( !MWNamespace::exists( $ns ) ) {
 567                         return null;
 568                 }
 569
 570                 $t = new Title();
 571                 $t->mDbkeyform = self::makeName( $ns, $title, $fragment, $interwiki, true );
 572
 573                 try {
 574                         $t->secureAndSplit();
 575                         return $t;
 576                 } catch ( MalformedTitleException $ex ) {
 577                         return null;
 578                 }
 579         }
 580
 581         /**
 582          * Create a new Title for the Main Page
 583          *
 584          * @return Title The new object
 585          */
 586         public static function newMainPage() {
 587                 $title = self::newFromText( wfMessage( 'mainpage' )->inContentLanguage()->text() );
 588                 // Don't give fatal errors if the message is broken
 589                 if ( !$title ) {
 590                         $title = self::newFromText( 'Main Page' );
 591                 }
 592                 return $title;
 593         }
 594
 595         /**
 596          * Get the prefixed DB key associated with an ID
 597          *
 598          * @param int $id The page_id of the article
 599          * @return Title|null An object representing the article, or null if no such article was found
 600          */
 601         public static function nameOf( $id ) {
 602                 $dbr = wfGetDB( DB_REPLICA );
 603
 604                 $s = $dbr->selectRow(
 605                         'page',
 606                         [ 'page_namespace', 'page_title' ],
 607                         [ 'page_id' => $id ],
 608                         __METHOD__
 609                 );
 610                 if ( $s === false ) {
 611                         return null;
 612                 }
 613
 614                 $n = self::makeName( $s->page_namespace, $s->page_title );
 615                 return $n;
 616         }
 617
 618         /**
 619          * Get a regex character class describing the legal characters in a link
 620          *
 621          * @return string The list of characters, not delimited
 622          */
 623         public static function legalChars() {
 624                 global $wgLegalTitleChars;
 625                 return $wgLegalTitleChars;
 626         }
 627
 628         /**
 629          * Returns a simple regex that will match on characters and sequences invalid in titles.
 630          * Note that this doesn't pick up many things that could be wrong with titles, but that
 631          * replacing this regex with something valid will make many titles valid.
 632          *
 633          * @deprecated since 1.25, use MediaWikiTitleCodec::getTitleInvalidRegex() instead
 634          *
 635          * @return string Regex string
 636          */
 637         static function getTitleInvalidRegex() {
 638                 wfDeprecated( __METHOD__, '1.25' );
 639                 return MediaWikiTitleCodec::getTitleInvalidRegex();
 640         }
 641
 642         /**
 643          * Utility method for converting a character sequence from bytes to Unicode.
 644          *
 645          * Primary usecase being converting $wgLegalTitleChars to a sequence usable in
 646          * javascript, as PHP uses UTF-8 bytes where javascript uses Unicode code units.
 647          *
 648          * @param string $byteClass
 649          * @return string
 650          */
 651         public static function convertByteClassToUnicodeClass( $byteClass ) {
 652                 $length = strlen( $byteClass );
 653                 // Input token queue
 654                 $x0 = $x1 = $x2 = '';
 655                 // Decoded queue
 656                 $d0 = $d1 = $d2 = '';
 657                 // Decoded integer codepoints
 658                 $ord0 = $ord1 = $ord2 = 0;
 659                 // Re-encoded queue
 660                 $r0 = $r1 = $r2 = '';
 661                 // Output
 662                 $out = '';
 663                 // Flags
 664                 $allowUnicode = false;
 665                 for ( $pos = 0; $pos < $length; $pos++ ) {
 666                         // Shift the queues down
 667                         $x2 = $x1;
 668                         $x1 = $x0;
 669                         $d2 = $d1;
 670                         $d1 = $d0;
 671                         $ord2 = $ord1;
 672                         $ord1 = $ord0;
 673                         $r2 = $r1;
 674                         $r1 = $r0;
 675                         // Load the current input token and decoded values
 676                         $inChar = $byteClass[$pos];
 677                         if ( $inChar == '\\' ) {
 678                                 if ( preg_match( '/x([0-9a-fA-F]{2})/A', $byteClass, $m, 0, $pos + 1 ) ) {
 679                                         $x0 = $inChar . $m[0];
 680                                         $d0 = chr( hexdec( $m[1] ) );
 681                                         $pos += strlen( $m[0] );
 682                                 } elseif ( preg_match( '/[0-7]{3}/A', $byteClass, $m, 0, $pos + 1 ) ) {
 683                                         $x0 = $inChar . $m[0];
 684                                         $d0 = chr( octdec( $m[0] ) );
 685                                         $pos += strlen( $m[0] );
 686                                 } elseif ( $pos + 1 >= $length ) {
 687                                         $x0 = $d0 = '\\';
 688                                 } else {
 689                                         $d0 = $byteClass[$pos + 1];
 690                                         $x0 = $inChar . $d0;
 691                                         $pos += 1;
 692                                 }
 693                         } else {
 694                                 $x0 = $d0 = $inChar;
 695                         }
 696                         $ord0 = ord( $d0 );
 697                         // Load the current re-encoded value
 698                         if ( $ord0 < 32 || $ord0 == 0x7f ) {
 699                                 $r0 = sprintf( '\x%02x', $ord0 );
 700                         } elseif ( $ord0 >= 0x80 ) {
 701                                 // Allow unicode if a single high-bit character appears
 702                                 $r0 = sprintf( '\x%02x', $ord0 );
 703                                 $allowUnicode = true;
 704                         } elseif ( strpos( '-\\[]^', $d0 ) !== false ) {
 705                                 $r0 = '\\' . $d0;
 706                         } else {
 707                                 $r0 = $d0;
 708                         }
 709                         // Do the output
 710                         if ( $x0 !== '' && $x1 === '-' && $x2 !== '' ) {
 711                                 // Range
 712                                 if ( $ord2 > $ord0 ) {
 713                                         // Empty range
 714                                 } elseif ( $ord0 >= 0x80 ) {
 715                                         // Unicode range
 716                                         $allowUnicode = true;
 717                                         if ( $ord2 < 0x80 ) {
 718                                                 // Keep the non-unicode section of the range
 719                                                 $out .= "$r2-\\x7F";
 720                                         }
 721                                 } else {
 722                                         // Normal range
 723                                         $out .= "$r2-$r0";
 724                                 }
 725                                 // Reset state to the initial value
 726                                 $x0 = $x1 = $d0 = $d1 = $r0 = $r1 = '';
 727                         } elseif ( $ord2 < 0x80 ) {
 728                                 // ASCII character
 729                                 $out .= $r2;
 730                         }
 731                 }
 732                 if ( $ord1 < 0x80 ) {
 733                         $out .= $r1;
 734                 }
 735                 if ( $ord0 < 0x80 ) {
 736                         $out .= $r0;
 737                 }
 738                 if ( $allowUnicode ) {
 739                         $out .= '\u0080-\uFFFF';
 740                 }
 741                 return $out;
 742         }
 743
 744         /**
 745          * Make a prefixed DB key from a DB key and a namespace index
 746          *
 747          * @param int $ns Numerical representation of the namespace
 748          * @param string $title The DB key form the title
 749          * @param string $fragment The link fragment (after the "#")
 750          * @param string $interwiki The interwiki prefix
 751          * @param bool $canonicalNamespace If true, use the canonical name for
 752          *   $ns instead of the localized version.
 753          * @return string The prefixed form of the title
 754          */
 755         public static function makeName( $ns, $title, $fragment = '', $interwiki = '',
 756                 $canonicalNamespace = false
 757         ) {
 758                 global $wgContLang;
 759
 760                 if ( $canonicalNamespace ) {
 761                         $namespace = MWNamespace::getCanonicalName( $ns );
 762                 } else {
 763                         $namespace = $wgContLang->getNsText( $ns );
 764                 }
 765                 $name = $namespace == '' ? $title : "$namespace:$title";
 766                 if ( strval( $interwiki ) != '' ) {
 767                         $name = "$interwiki:$name";
 768                 }
 769                 if ( strval( $fragment ) != '' ) {
 770                         $name .= '#' . $fragment;
 771                 }
 772                 return $name;
 773         }
 774
 775         /**
 776          * Escape a text fragment, say from a link, for a URL
 777          *
 778          * @deprecated since 1.30, use Sanitizer::escapeIdForLink() or escapeIdForExternalInterwiki()
 779          *
 780          * @param string $fragment Containing a URL or link fragment (after the "#")
 781          * @return string Escaped string
 782          */
 783         static function escapeFragmentForURL( $fragment ) {
 784                 wfDeprecated( __METHOD__, '1.30' );
 785                 # Note that we don't urlencode the fragment.  urlencoded Unicode
 786                 # fragments appear not to work in IE (at least up to 7) or in at least
 787                 # one version of Opera 9.x.  The W3C validator, for one, doesn't seem
 788                 # to care if they aren't encoded.
 789                 return Sanitizer::escapeId( $fragment, 'noninitial' );
 790         }
 791
 792         /**
 793          * Callback for usort() to do title sorts by (namespace, title)
 794          *
 795          * @param LinkTarget $a
 796          * @param LinkTarget $b
 797          *
 798          * @return int Result of string comparison, or namespace comparison
 799          */
 800         public static function compare( LinkTarget $a, LinkTarget $b ) {
 801                 if ( $a->getNamespace() == $b->getNamespace() ) {
 802                         return strcmp( $a->getText(), $b->getText() );
 803                 } else {
 804                         return $a->getNamespace() - $b->getNamespace();
 805                 }
 806         }
 807
 808         /**
 809          * Returns true if the title is valid, false if it is invalid.
 810          *
 811          * Valid titles can be round-tripped via makeTitleSafe() and newFromText().
 812          * Invalid titles may get returned from makeTitle(), and it may be useful to
 813          * allow them to exist, e.g. in order to process log entries about pages in
 814          * namespaces that belong to extensions that are no longer installed.
 815          *
 816          * @note This method is relatively expensive. When constructing Title
 817          * objects that need to be valid, use an instantiator method that is guaranteed
 818          * to return valid titles, such as makeTitleSafe() or newFromText().
 819          *
 820          * @return bool
 821          */
 822         public function isValid() {
 823                 $ns = $this->getNamespace();
 824
 825                 if ( !MWNamespace::exists( $ns ) ) {
 826                         return false;
 827                 }
 828
 829                 try {
 830                         $parser = MediaWikiServices::getInstance()->getTitleParser();
 831                         $parser->parseTitle( $this->getDBkey(), $ns );
 832                         return true;
 833                 } catch ( MalformedTitleException $ex ) {
 834                         return false;
 835                 }
 836         }
 837
 838         /**
 839          * Determine whether the object refers to a page within
 840          * this project (either this wiki or a wiki with a local
 841          * interwiki, see https://www.mediawiki.org/wiki/Manual:Interwiki_table#iw_local )
 842          *
 843          * @return bool True if this is an in-project interwiki link or a wikilink, false otherwise
 844          */
 845         public function isLocal() {
 846                 if ( $this->isExternal() ) {
 847                         $iw = self::getInterwikiLookup()->fetch( $this->mInterwiki );
 848                         if ( $iw ) {
 849                                 return $iw->isLocal();
 850                         }
 851                 }
 852                 return true;
 853         }
 854
 855         /**
 856          * Is this Title interwiki?
 857          *
 858          * @return bool
 859          */
 860         public function isExternal() {
 861                 return $this->mInterwiki !== '';
 862         }
 863
 864         /**
 865          * Get the interwiki prefix
 866          *
 867          * Use Title::isExternal to check if a interwiki is set
 868          *
 869          * @return string Interwiki prefix
 870          */
 871         public function getInterwiki() {
 872                 return $this->mInterwiki;
 873         }
 874
 875         /**
 876          * Was this a local interwiki link?
 877          *
 878          * @return bool
 879          */
 880         public function wasLocalInterwiki() {
 881                 return $this->mLocalInterwiki;
 882         }
 883
 884         /**
 885          * Determine whether the object refers to a page within
 886          * this project and is transcludable.
 887          *
 888          * @return bool True if this is transcludable
 889          */
 890         public function isTrans() {
 891                 if ( !$this->isExternal() ) {
 892                         return false;
 893                 }
 894
 895                 return self::getInterwikiLookup()->fetch( $this->mInterwiki )->isTranscludable();
 896         }
 897
 898         /**
 899          * Returns the DB name of the distant wiki which owns the object.
 900          *
 901          * @return string|false The DB name
 902          */
 903         public function getTransWikiID() {
 904                 if ( !$this->isExternal() ) {
 905                         return false;
 906                 }
 907
 908                 return self::getInterwikiLookup()->fetch( $this->mInterwiki )->getWikiID();
 909         }
 910
 911         /**
 912          * Get a TitleValue object representing this Title.
 913          *
 914          * @note Not all valid Titles have a corresponding valid TitleValue
 915          * (e.g. TitleValues cannot represent page-local links that have a
 916          * fragment but no title text).
 917          *
 918          * @return TitleValue|null
 919          */
 920         public function getTitleValue() {
 921                 if ( $this->mTitleValue === null ) {
 922                         try {
 923                                 $this->mTitleValue = new TitleValue(
 924                                         $this->getNamespace(),
 925                                         $this->getDBkey(),
 926                                         $this->getFragment(),
 927                                         $this->getInterwiki()
 928                                 );
 929                         } catch ( InvalidArgumentException $ex ) {
 930                                 wfDebug( __METHOD__ . ': Can\'t create a TitleValue for [[' .
 931                                         $this->getPrefixedText() . ']]: ' . $ex->getMessage() . "\n" );
 932                         }
 933                 }
 934
 935                 return $this->mTitleValue;
 936         }
 937
 938         /**
 939          * Get the text form (spaces not underscores) of the main part
 940          *
 941          * @return string Main part of the title
 942          */
 943         public function getText() {
 944                 return $this->mTextform;
 945         }
 946
 947         /**
 948          * Get the URL-encoded form of the main part
 949          *
 950          * @return string Main part of the title, URL-encoded
 951          */
 952         public function getPartialURL() {
 953                 return $this->mUrlform;
 954         }
 955
 956         /**
 957          * Get the main part with underscores
 958          *
 959          * @return string Main part of the title, with underscores
 960          */
 961         public function getDBkey() {
 962                 return $this->mDbkeyform;
 963         }
 964
 965         /**
 966          * Get the DB key with the initial letter case as specified by the user
 967          *
 968          * @return string DB key
 969          */
 970         function getUserCaseDBKey() {
 971                 if ( !is_null( $this->mUserCaseDBKey ) ) {
 972                         return $this->mUserCaseDBKey;
 973                 } else {
 974                         // If created via makeTitle(), $this->mUserCaseDBKey is not set.
 975                         return $this->mDbkeyform;
 976                 }
 977         }
 978
 979         /**
 980          * Get the namespace index, i.e. one of the NS_xxxx constants.
 981          *
 982          * @return int Namespace index
 983          */
 984         public function getNamespace() {
 985                 return $this->mNamespace;
 986         }
 987
 988         /**
 989          * Get the page's content model id, see the CONTENT_MODEL_XXX constants.
 990          *
 991          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
 992          * @return string Content model id
 993          */
 994         public function getContentModel( $flags = 0 ) {
 995                 if ( !$this->mForcedContentModel
 996                         && ( !$this->mContentModel || $flags === self::GAID_FOR_UPDATE )
 997                         && $this->getArticleID( $flags )
 998                 ) {
 999                         $linkCache = LinkCache::singleton();
1000                         $linkCache->addLinkObj( $this ); # in case we already had an article ID
1001                         $this->mContentModel = $linkCache->getGoodLinkFieldObj( $this, 'model' );
1002                 }
1003
1004                 if ( !$this->mContentModel ) {
1005                         $this->mContentModel = ContentHandler::getDefaultModelFor( $this );
1006                 }
1007
1008                 return $this->mContentModel;
1009         }
1010
1011         /**
1012          * Convenience method for checking a title's content model name
1013          *
1014          * @param string $id The content model ID (use the CONTENT_MODEL_XXX constants).
1015          * @return bool True if $this->getContentModel() == $id
1016          */
1017         public function hasContentModel( $id ) {
1018                 return $this->getContentModel() == $id;
1019         }
1020
1021         /**
1022          * Set a proposed content model for the page for permissions
1023          * checking. This does not actually change the content model
1024          * of a title!
1025          *
1026          * Additionally, you should make sure you've checked
1027          * ContentHandler::canBeUsedOn() first.
1028          *
1029          * @since 1.28
1030          * @param string $model CONTENT_MODEL_XXX constant
1031          */
1032         public function setContentModel( $model ) {
1033                 $this->mContentModel = $model;
1034                 $this->mForcedContentModel = true;
1035         }
1036
1037         /**
1038          * Get the namespace text
1039          *
1040          * @return string|false Namespace text
1041          */
1042         public function getNsText() {
1043                 if ( $this->isExternal() ) {
1044                         // This probably shouldn't even happen,
1045                         // but for interwiki transclusion it sometimes does.
1046                         // Use the canonical namespaces if possible to try to
1047                         // resolve a foreign namespace.
1048                         if ( MWNamespace::exists( $this->mNamespace ) ) {
1049                                 return MWNamespace::getCanonicalName( $this->mNamespace );
1050                         }
1051                 }
1052
1053                 try {
1054                         $formatter = self::getTitleFormatter();
1055                         return $formatter->getNamespaceName( $this->mNamespace, $this->mDbkeyform );
1056                 } catch ( InvalidArgumentException $ex ) {
1057                         wfDebug( __METHOD__ . ': ' . $ex->getMessage() . "\n" );
1058                         return false;
1059                 }
1060         }
1061
1062         /**
1063          * Get the namespace text of the subject (rather than talk) page
1064          *
1065          * @return string Namespace text
1066          */
1067         public function getSubjectNsText() {
1068                 global $wgContLang;
1069                 return $wgContLang->getNsText( MWNamespace::getSubject( $this->mNamespace ) );
1070         }
1071
1072         /**
1073          * Get the namespace text of the talk page
1074          *
1075          * @return string Namespace text
1076          */
1077         public function getTalkNsText() {
1078                 global $wgContLang;
1079                 return $wgContLang->getNsText( MWNamespace::getTalk( $this->mNamespace ) );
1080         }
1081
1082         /**
1083          * Can this title have a corresponding talk page?
1084          *
1085          * @deprecated since 1.30, use canHaveTalkPage() instead.
1086          *
1087          * @return bool True if this title either is a talk page or can have a talk page associated.
1088          */
1089         public function canTalk() {
1090                 return $this->canHaveTalkPage();
1091         }
1092
1093         /**
1094          * Can this title have a corresponding talk page?
1095          *
1096          * @see MWNamespace::hasTalkNamespace
1097          * @since 1.30
1098          *
1099          * @return bool True if this title either is a talk page or can have a talk page associated.
1100          */
1101         public function canHaveTalkPage() {
1102                 return MWNamespace::hasTalkNamespace( $this->mNamespace );
1103         }
1104
1105         /**
1106          * Is this in a namespace that allows actual pages?
1107          *
1108          * @return bool
1109          */
1110         public function canExist() {
1111                 return $this->mNamespace >= NS_MAIN;
1112         }
1113
1114         /**
1115          * Can this title be added to a user's watchlist?
1116          *
1117          * @return bool
1118          */
1119         public function isWatchable() {
1120                 return !$this->isExternal() && MWNamespace::isWatchable( $this->getNamespace() );
1121         }
1122
1123         /**
1124          * Returns true if this is a special page.
1125          *
1126          * @return bool
1127          */
1128         public function isSpecialPage() {
1129                 return $this->getNamespace() == NS_SPECIAL;
1130         }
1131
1132         /**
1133          * Returns true if this title resolves to the named special page
1134          *
1135          * @param string $name The special page name
1136          * @return bool
1137          */
1138         public function isSpecial( $name ) {
1139                 if ( $this->isSpecialPage() ) {
1140                         list( $thisName, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $this->getDBkey() );
1141                         if ( $name == $thisName ) {
1142                                 return true;
1143                         }
1144                 }
1145                 return false;
1146         }
1147
1148         /**
1149          * If the Title refers to a special page alias which is not the local default, resolve
1150          * the alias, and localise the name as necessary.  Otherwise, return $this
1151          *
1152          * @return Title
1153          */
1154         public function fixSpecialName() {
1155                 if ( $this->isSpecialPage() ) {
1156                         list( $canonicalName, $par ) = SpecialPageFactory::resolveAlias( $this->mDbkeyform );
1157                         if ( $canonicalName ) {
1158                                 $localName = SpecialPageFactory::getLocalNameFor( $canonicalName, $par );
1159                                 if ( $localName != $this->mDbkeyform ) {
1160                                         return self::makeTitle( NS_SPECIAL, $localName );
1161                                 }
1162                         }
1163                 }
1164                 return $this;
1165         }
1166
1167         /**
1168          * Returns true if the title is inside the specified namespace.
1169          *
1170          * Please make use of this instead of comparing to getNamespace()
1171          * This function is much more resistant to changes we may make
1172          * to namespaces than code that makes direct comparisons.
1173          * @param int $ns The namespace
1174          * @return bool
1175          * @since 1.19
1176          */
1177         public function inNamespace( $ns ) {
1178                 return MWNamespace::equals( $this->getNamespace(), $ns );
1179         }
1180
1181         /**
1182          * Returns true if the title is inside one of the specified namespaces.
1183          *
1184          * @param int|int[] $namespaces,... The namespaces to check for
1185          * @return bool
1186          * @since 1.19
1187          */
1188         public function inNamespaces( /* ... */ ) {
1189                 $namespaces = func_get_args();
1190                 if ( count( $namespaces ) > 0 && is_array( $namespaces[0] ) ) {
1191                         $namespaces = $namespaces[0];
1192                 }
1193
1194                 foreach ( $namespaces as $ns ) {
1195                         if ( $this->inNamespace( $ns ) ) {
1196                                 return true;
1197                         }
1198                 }
1199
1200                 return false;
1201         }
1202
1203         /**
1204          * Returns true if the title has the same subject namespace as the
1205          * namespace specified.
1206          * For example this method will take NS_USER and return true if namespace
1207          * is either NS_USER or NS_USER_TALK since both of them have NS_USER
1208          * as their subject namespace.
1209          *
1210          * This is MUCH simpler than individually testing for equivalence
1211          * against both NS_USER and NS_USER_TALK, and is also forward compatible.
1212          * @since 1.19
1213          * @param int $ns
1214          * @return bool
1215          */
1216         public function hasSubjectNamespace( $ns ) {
1217                 return MWNamespace::subjectEquals( $this->getNamespace(), $ns );
1218         }
1219
1220         /**
1221          * Is this Title in a namespace which contains content?
1222          * In other words, is this a content page, for the purposes of calculating
1223          * statistics, etc?
1224          *
1225          * @return bool
1226          */
1227         public function isContentPage() {
1228                 return MWNamespace::isContent( $this->getNamespace() );
1229         }
1230
1231         /**
1232          * Would anybody with sufficient privileges be able to move this page?
1233          * Some pages just aren't movable.
1234          *
1235          * @return bool
1236          */
1237         public function isMovable() {
1238                 if ( !MWNamespace::isMovable( $this->getNamespace() ) || $this->isExternal() ) {
1239                         // Interwiki title or immovable namespace. Hooks don't get to override here
1240                         return false;
1241                 }
1242
1243                 $result = true;
1244                 Hooks::run( 'TitleIsMovable', [ $this, &$result ] );
1245                 return $result;
1246         }
1247
1248         /**
1249          * Is this the mainpage?
1250          * @note Title::newFromText seems to be sufficiently optimized by the title
1251          * cache that we don't need to over-optimize by doing direct comparisons and
1252          * accidentally creating new bugs where $title->equals( Title::newFromText() )
1253          * ends up reporting something differently than $title->isMainPage();
1254          *
1255          * @since 1.18
1256          * @return bool
1257          */
1258         public function isMainPage() {
1259                 return $this->equals( self::newMainPage() );
1260         }
1261
1262         /**
1263          * Is this a subpage?
1264          *
1265          * @return bool
1266          */
1267         public function isSubpage() {
1268                 return MWNamespace::hasSubpages( $this->mNamespace )
1269                         ? strpos( $this->getText(), '/' ) !== false
1270                         : false;
1271         }
1272
1273         /**
1274          * Is this a conversion table for the LanguageConverter?
1275          *
1276          * @return bool
1277          */
1278         public function isConversionTable() {
1279                 // @todo ConversionTable should become a separate content model.
1280
1281                 return $this->getNamespace() == NS_MEDIAWIKI &&
1282                         strpos( $this->getText(), 'Conversiontable/' ) === 0;
1283         }
1284
1285         /**
1286          * Does that page contain wikitext, or it is JS, CSS or whatever?
1287          *
1288          * @return bool
1289          */
1290         public function isWikitextPage() {
1291                 return $this->hasContentModel( CONTENT_MODEL_WIKITEXT );
1292         }
1293
1294         /**
1295          * Could this page contain custom CSS or JavaScript for the global UI.
1296          * This is generally true for pages in the MediaWiki namespace having CONTENT_MODEL_CSS
1297          * or CONTENT_MODEL_JAVASCRIPT.
1298          *
1299          * This method does *not* return true for per-user JS/CSS. Use isCssJsSubpage()
1300          * for that!
1301          *
1302          * Note that this method should not return true for pages that contain and
1303          * show "inactive" CSS or JS.
1304          *
1305          * @return bool
1306          * @since 1.31
1307          */
1308         public function isSiteConfigPage() {
1309                 return (
1310                         NS_MEDIAWIKI == $this->mNamespace
1311                         && (
1312                                 $this->hasContentModel( CONTENT_MODEL_CSS )
1313                                 || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT )
1314                         )
1315                 );
1316         }
1317
1318         /**
1319          * @return bool
1320          * @deprecated Since 1.31; use ::isSiteConfigPage() instead
1321          */
1322         public function isCssOrJsPage() {
1323                 // wfDeprecated( __METHOD__, '1.31' );
1324                 return ( NS_MEDIAWIKI == $this->mNamespace
1325                                 && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1326                                         || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) ) );
1327         }
1328
1329         /**
1330          * Is this a "config" (.css or .js) sub-page of a user page?
1331          *
1332          * @return bool
1333          * @since 1.31
1334          */
1335         public function isUserConfigPage() {
1336                 return (
1337                         NS_USER == $this->mNamespace
1338                         && $this->isSubpage()
1339                         && (
1340                                 $this->hasContentModel( CONTENT_MODEL_CSS )
1341                                 || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT )
1342                         )
1343                 );
1344         }
1345
1346         /**
1347          * @return bool
1348          * @deprecated Since 1.31; use ::isUserConfigPage() instead
1349          */
1350         public function isCssJsSubpage() {
1351                 // wfDeprecated( __METHOD__, '1.31' );
1352                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1353                                 && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1354                                         || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) ) );
1355         }
1356
1357         /**
1358          * Trim down a .css or .js subpage title to get the corresponding skin name
1359          *
1360          * @return string Containing skin name from .css or .js subpage title
1361          * @since 1.31
1362          */
1363         public function getSkinFromConfigSubpage() {
1364                 $subpage = explode( '/', $this->mTextform );
1365                 $subpage = $subpage[count( $subpage ) - 1];
1366                 $lastdot = strrpos( $subpage, '.' );
1367                 if ( $lastdot === false ) {
1368                         return $subpage; # Never happens: only called for names ending in '.css' or '.js'
1369                 }
1370                 return substr( $subpage, 0, $lastdot );
1371         }
1372
1373         /**
1374          * @deprecated Since 1.31; use ::getSkinFromConfigSubpage() instead
1375          * @return string Containing skin name from .css or .js subpage title
1376          */
1377         public function getSkinFromCssJsSubpage() {
1378                 wfDeprecated( __METHOD__, '1.31' );
1379                 return $this->getSkinFromConfigSubpage();
1380         }
1381
1382         /**
1383          * Is this a CSS "config" sub-page of a user page?
1384          *
1385          * @return bool
1386          * @since 1.31
1387          */
1388         public function isUserCssConfigPage() {
1389                 return (
1390                         NS_USER == $this->mNamespace
1391                         && $this->isSubpage()
1392                         && $this->hasContentModel( CONTENT_MODEL_CSS )
1393                 );
1394         }
1395
1396         /**
1397          * @deprecated Since 1.31; use ::isUserCssConfigPage()
1398          * @return bool
1399          */
1400         public function isCssSubpage() {
1401                 // wfDeprecated( __METHOD__, '1.31' );
1402                 return $this->isUserCssConfigPage();
1403         }
1404
1405         /**
1406          * Is this a .js subpage of a user page?
1407          *
1408          * @return bool
1409          * @since 1.31
1410          */
1411         public function isUserJsConfigPage() {
1412                 return (
1413                         NS_USER == $this->mNamespace
1414                         && $this->isSubpage()
1415                         && $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT )
1416                 );
1417         }
1418
1419         /**
1420          * @deprecated Since 1.31; use ::isUserCssConfigPage()
1421          * @return bool
1422          */
1423         public function isJsSubpage() {
1424                 // wfDeprecated( __METHOD__, '1.31' );
1425                 return $this->isUserJsConfigPage();
1426         }
1427
1428         /**
1429          * Is this a talk page of some sort?
1430          *
1431          * @return bool
1432          */
1433         public function isTalkPage() {
1434                 return MWNamespace::isTalk( $this->getNamespace() );
1435         }
1436
1437         /**
1438          * Get a Title object associated with the talk page of this article
1439          *
1440          * @return Title The object for the talk page
1441          */
1442         public function getTalkPage() {
1443                 return self::makeTitle( MWNamespace::getTalk( $this->getNamespace() ), $this->getDBkey() );
1444         }
1445
1446         /**
1447          * Get a Title object associated with the talk page of this article,
1448          * if such a talk page can exist.
1449          *
1450          * @since 1.30
1451          *
1452          * @return Title|null The object for the talk page,
1453          *         or null if no associated talk page can exist, according to canHaveTalkPage().
1454          */
1455         public function getTalkPageIfDefined() {
1456                 if ( !$this->canHaveTalkPage() ) {
1457                         return null;
1458                 }
1459
1460                 return $this->getTalkPage();
1461         }
1462
1463         /**
1464          * Get a title object associated with the subject page of this
1465          * talk page
1466          *
1467          * @return Title The object for the subject page
1468          */
1469         public function getSubjectPage() {
1470                 // Is this the same title?
1471                 $subjectNS = MWNamespace::getSubject( $this->getNamespace() );
1472                 if ( $this->getNamespace() == $subjectNS ) {
1473                         return $this;
1474                 }
1475                 return self::makeTitle( $subjectNS, $this->getDBkey() );
1476         }
1477
1478         /**
1479          * Get the other title for this page, if this is a subject page
1480          * get the talk page, if it is a subject page get the talk page
1481          *
1482          * @since 1.25
1483          * @throws MWException If the page doesn't have an other page
1484          * @return Title
1485          */
1486         public function getOtherPage() {
1487                 if ( $this->isSpecialPage() ) {
1488                         throw new MWException( 'Special pages cannot have other pages' );
1489                 }
1490                 if ( $this->isTalkPage() ) {
1491                         return $this->getSubjectPage();
1492                 } else {
1493                         if ( !$this->canHaveTalkPage() ) {
1494                                 throw new MWException( "{$this->getPrefixedText()} does not have an other page" );
1495                         }
1496                         return $this->getTalkPage();
1497                 }
1498         }
1499
1500         /**
1501          * Get the default namespace index, for when there is no namespace
1502          *
1503          * @return int Default namespace index
1504          */
1505         public function getDefaultNamespace() {
1506                 return $this->mDefaultNamespace;
1507         }
1508
1509         /**
1510          * Get the Title fragment (i.e.\ the bit after the #) in text form
1511          *
1512          * Use Title::hasFragment to check for a fragment
1513          *
1514          * @return string Title fragment
1515          */
1516         public function getFragment() {
1517                 return $this->mFragment;
1518         }
1519
1520         /**
1521          * Check if a Title fragment is set
1522          *
1523          * @return bool
1524          * @since 1.23
1525          */
1526         public function hasFragment() {
1527                 return $this->mFragment !== '';
1528         }
1529
1530         /**
1531          * Get the fragment in URL form, including the "#" character if there is one
1532          *
1533          * @return string Fragment in URL form
1534          */
1535         public function getFragmentForURL() {
1536                 if ( !$this->hasFragment() ) {
1537                         return '';
1538                 } elseif ( $this->isExternal()
1539                         && !self::getInterwikiLookup()->fetch( $this->mInterwiki )->isLocal()
1540                 ) {
1541                         return '#' . Sanitizer::escapeIdForExternalInterwiki( $this->getFragment() );
1542                 }
1543                 return '#' . Sanitizer::escapeIdForLink( $this->getFragment() );
1544         }
1545
1546         /**
1547          * Set the fragment for this title. Removes the first character from the
1548          * specified fragment before setting, so it assumes you're passing it with
1549          * an initial "#".
1550          *
1551          * Deprecated for public use, use Title::makeTitle() with fragment parameter,
1552          * or Title::createFragmentTarget().
1553          * Still in active use privately.
1554          *
1555          * @private
1556          * @param string $fragment Text
1557          */
1558         public function setFragment( $fragment ) {
1559                 $this->mFragment = strtr( substr( $fragment, 1 ), '_', ' ' );
1560         }
1561
1562         /**
1563          * Creates a new Title for a different fragment of the same page.
1564          *
1565          * @since 1.27
1566          * @param string $fragment
1567          * @return Title
1568          */
1569         public function createFragmentTarget( $fragment ) {
1570                 return self::makeTitle(
1571                         $this->getNamespace(),
1572                         $this->getText(),
1573                         $fragment,
1574                         $this->getInterwiki()
1575                 );
1576         }
1577
1578         /**
1579          * Prefix some arbitrary text with the namespace or interwiki prefix
1580          * of this object
1581          *
1582          * @param string $name The text
1583          * @return string The prefixed text
1584          */
1585         private function prefix( $name ) {
1586                 global $wgContLang;
1587
1588                 $p = '';
1589                 if ( $this->isExternal() ) {
1590                         $p = $this->mInterwiki . ':';
1591                 }
1592
1593                 if ( 0 != $this->mNamespace ) {
1594                         $nsText = $this->getNsText();
1595
1596                         if ( $nsText === false ) {
1597                                 // See T165149. Awkward, but better than erroneously linking to the main namespace.
1598                                 $nsText = $wgContLang->getNsText( NS_SPECIAL ) . ":Badtitle/NS{$this->mNamespace}";
1599                         }
1600
1601                         $p .= $nsText . ':';
1602                 }
1603                 return $p . $name;
1604         }
1605
1606         /**
1607          * Get the prefixed database key form
1608          *
1609          * @return string The prefixed title, with underscores and
1610          *  any interwiki and namespace prefixes
1611          */
1612         public function getPrefixedDBkey() {
1613                 $s = $this->prefix( $this->mDbkeyform );
1614                 $s = strtr( $s, ' ', '_' );
1615                 return $s;
1616         }
1617
1618         /**
1619          * Get the prefixed title with spaces.
1620          * This is the form usually used for display
1621          *
1622          * @return string The prefixed title, with spaces
1623          */
1624         public function getPrefixedText() {
1625                 if ( $this->mPrefixedText === null ) {
1626                         $s = $this->prefix( $this->mTextform );
1627                         $s = strtr( $s, '_', ' ' );
1628                         $this->mPrefixedText = $s;
1629                 }
1630                 return $this->mPrefixedText;
1631         }
1632
1633         /**
1634          * Return a string representation of this title
1635          *
1636          * @return string Representation of this title
1637          */
1638         public function __toString() {
1639                 return $this->getPrefixedText();
1640         }
1641
1642         /**
1643          * Get the prefixed title with spaces, plus any fragment
1644          * (part beginning with '#')
1645          *
1646          * @return string The prefixed title, with spaces and the fragment, including '#'
1647          */
1648         public function getFullText() {
1649                 $text = $this->getPrefixedText();
1650                 if ( $this->hasFragment() ) {
1651                         $text .= '#' . $this->getFragment();
1652                 }
1653                 return $text;
1654         }
1655
1656         /**
1657          * Get the root page name text without a namespace, i.e. the leftmost part before any slashes
1658          *
1659          * @par Example:
1660          * @code
1661          * Title::newFromText('User:Foo/Bar/Baz')->getRootText();
1662          * # returns: 'Foo'
1663          * @endcode
1664          *
1665          * @return string Root name
1666          * @since 1.20
1667          */
1668         public function getRootText() {
1669                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1670                         return $this->getText();
1671                 }
1672
1673                 return strtok( $this->getText(), '/' );
1674         }
1675
1676         /**
1677          * Get the root page name title, i.e. the leftmost part before any slashes
1678          *
1679          * @par Example:
1680          * @code
1681          * Title::newFromText('User:Foo/Bar/Baz')->getRootTitle();
1682          * # returns: Title{User:Foo}
1683          * @endcode
1684          *
1685          * @return Title Root title
1686          * @since 1.20
1687          */
1688         public function getRootTitle() {
1689                 return self::makeTitle( $this->getNamespace(), $this->getRootText() );
1690         }
1691
1692         /**
1693          * Get the base page name without a namespace, i.e. the part before the subpage name
1694          *
1695          * @par Example:
1696          * @code
1697          * Title::newFromText('User:Foo/Bar/Baz')->getBaseText();
1698          * # returns: 'Foo/Bar'
1699          * @endcode
1700          *
1701          * @return string Base name
1702          */
1703         public function getBaseText() {
1704                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1705                         return $this->getText();
1706                 }
1707
1708                 $parts = explode( '/', $this->getText() );
1709                 # Don't discard the real title if there's no subpage involved
1710                 if ( count( $parts ) > 1 ) {
1711                         unset( $parts[count( $parts ) - 1] );
1712                 }
1713                 return implode( '/', $parts );
1714         }
1715
1716         /**
1717          * Get the base page name title, i.e. the part before the subpage name
1718          *
1719          * @par Example:
1720          * @code
1721          * Title::newFromText('User:Foo/Bar/Baz')->getBaseTitle();
1722          * # returns: Title{User:Foo/Bar}
1723          * @endcode
1724          *
1725          * @return Title Base title
1726          * @since 1.20
1727          */
1728         public function getBaseTitle() {
1729                 return self::makeTitle( $this->getNamespace(), $this->getBaseText() );
1730         }
1731
1732         /**
1733          * Get the lowest-level subpage name, i.e. the rightmost part after any slashes
1734          *
1735          * @par Example:
1736          * @code
1737          * Title::newFromText('User:Foo/Bar/Baz')->getSubpageText();
1738          * # returns: "Baz"
1739          * @endcode
1740          *
1741          * @return string Subpage name
1742          */
1743         public function getSubpageText() {
1744                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1745                         return $this->mTextform;
1746                 }
1747                 $parts = explode( '/', $this->mTextform );
1748                 return $parts[count( $parts ) - 1];
1749         }
1750
1751         /**
1752          * Get the title for a subpage of the current page
1753          *
1754          * @par Example:
1755          * @code
1756          * Title::newFromText('User:Foo/Bar/Baz')->getSubpage("Asdf");
1757          * # returns: Title{User:Foo/Bar/Baz/Asdf}
1758          * @endcode
1759          *
1760          * @param string $text The subpage name to add to the title
1761          * @return Title Subpage title
1762          * @since 1.20
1763          */
1764         public function getSubpage( $text ) {
1765                 return self::makeTitleSafe( $this->getNamespace(), $this->getText() . '/' . $text );
1766         }
1767
1768         /**
1769          * Get a URL-encoded form of the subpage text
1770          *
1771          * @return string URL-encoded subpage name
1772          */
1773         public function getSubpageUrlForm() {
1774                 $text = $this->getSubpageText();
1775                 $text = wfUrlencode( strtr( $text, ' ', '_' ) );
1776                 return $text;
1777         }
1778
1779         /**
1780          * Get a URL-encoded title (not an actual URL) including interwiki
1781          *
1782          * @return string The URL-encoded form
1783          */
1784         public function getPrefixedURL() {
1785                 $s = $this->prefix( $this->mDbkeyform );
1786                 $s = wfUrlencode( strtr( $s, ' ', '_' ) );
1787                 return $s;
1788         }
1789
1790         /**
1791          * Helper to fix up the get{Canonical,Full,Link,Local,Internal}URL args
1792          * get{Canonical,Full,Link,Local,Internal}URL methods accepted an optional
1793          * second argument named variant. This was deprecated in favor
1794          * of passing an array of option with a "variant" key
1795          * Once $query2 is removed for good, this helper can be dropped
1796          * and the wfArrayToCgi moved to getLocalURL();
1797          *
1798          * @since 1.19 (r105919)
1799          * @param array|string $query
1800          * @param string|string[]|bool $query2
1801          * @return string
1802          */
1803         private static function fixUrlQueryArgs( $query, $query2 = false ) {
1804                 if ( $query2 !== false ) {
1805                         wfDeprecated( "Title::get{Canonical,Full,Link,Local,Internal}URL " .
1806                                 "method called with a second parameter is deprecated. Add your " .
1807                                 "parameter to an array passed as the first parameter.", "1.19" );
1808                 }
1809                 if ( is_array( $query ) ) {
1810                         $query = wfArrayToCgi( $query );
1811                 }
1812                 if ( $query2 ) {
1813                         if ( is_string( $query2 ) ) {
1814                                 // $query2 is a string, we will consider this to be
1815                                 // a deprecated $variant argument and add it to the query
1816                                 $query2 = wfArrayToCgi( [ 'variant' => $query2 ] );
1817                         } else {
1818                                 $query2 = wfArrayToCgi( $query2 );
1819                         }
1820                         // If we have $query content add a & to it first
1821                         if ( $query ) {
1822                                 $query .= '&';
1823                         }
1824                         // Now append the queries together
1825                         $query .= $query2;
1826                 }
1827                 return $query;
1828         }
1829
1830         /**
1831          * Get a real URL referring to this title, with interwiki link and
1832          * fragment
1833          *
1834          * @see self::getLocalURL for the arguments.
1835          * @see wfExpandUrl
1836          * @param string|string[] $query
1837          * @param string|string[]|bool $query2
1838          * @param string|int|null $proto Protocol type to use in URL
1839          * @return string The URL
1840          */
1841         public function getFullURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1842                 $query = self::fixUrlQueryArgs( $query, $query2 );
1843
1844                 # Hand off all the decisions on urls to getLocalURL
1845                 $url = $this->getLocalURL( $query );
1846
1847                 # Expand the url to make it a full url. Note that getLocalURL has the
1848                 # potential to output full urls for a variety of reasons, so we use
1849                 # wfExpandUrl instead of simply prepending $wgServer
1850                 $url = wfExpandUrl( $url, $proto );
1851
1852                 # Finally, add the fragment.
1853                 $url .= $this->getFragmentForURL();
1854                 // Avoid PHP 7.1 warning from passing $this by reference
1855                 $titleRef = $this;
1856                 Hooks::run( 'GetFullURL', [ &$titleRef, &$url, $query ] );
1857                 return $url;
1858         }
1859
1860         /**
1861          * Get a url appropriate for making redirects based on an untrusted url arg
1862          *
1863          * This is basically the same as getFullUrl(), but in the case of external
1864          * interwikis, we send the user to a landing page, to prevent possible
1865          * phishing attacks and the like.
1866          *
1867          * @note Uses current protocol by default, since technically relative urls
1868          *   aren't allowed in redirects per HTTP spec, so this is not suitable for
1869          *   places where the url gets cached, as might pollute between
1870          *   https and non-https users.
1871          * @see self::getLocalURL for the arguments.
1872          * @param array|string $query
1873          * @param string $proto Protocol type to use in URL
1874          * @return string A url suitable to use in an HTTP location header.
1875          */
1876         public function getFullUrlForRedirect( $query = '', $proto = PROTO_CURRENT ) {
1877                 $target = $this;
1878                 if ( $this->isExternal() ) {
1879                         $target = SpecialPage::getTitleFor(
1880                                 'GoToInterwiki',
1881                                 $this->getPrefixedDBkey()
1882                         );
1883                 }
1884                 return $target->getFullURL( $query, false, $proto );
1885         }
1886
1887         /**
1888          * Get a URL with no fragment or server name (relative URL) from a Title object.
1889          * If this page is generated with action=render, however,
1890          * $wgServer is prepended to make an absolute URL.
1891          *
1892          * @see self::getFullURL to always get an absolute URL.
1893          * @see self::getLinkURL to always get a URL that's the simplest URL that will be
1894          *  valid to link, locally, to the current Title.
1895          * @see self::newFromText to produce a Title object.
1896          *
1897          * @param string|string[] $query An optional query string,
1898          *   not used for interwiki links. Can be specified as an associative array as well,
1899          *   e.g., array( 'action' => 'edit' ) (keys and values will be URL-escaped).
1900          *   Some query patterns will trigger various shorturl path replacements.
1901          * @param string|string[]|bool $query2 An optional secondary query array. This one MUST
1902          *   be an array. If a string is passed it will be interpreted as a deprecated
1903          *   variant argument and urlencoded into a variant= argument.
1904          *   This second query argument will be added to the $query
1905          *   The second parameter is deprecated since 1.19. Pass it as a key,value
1906          *   pair in the first parameter array instead.
1907          *
1908          * @return string String of the URL.
1909          */
1910         public function getLocalURL( $query = '', $query2 = false ) {
1911                 global $wgArticlePath, $wgScript, $wgServer, $wgRequest;
1912
1913                 $query = self::fixUrlQueryArgs( $query, $query2 );
1914
1915                 $interwiki = self::getInterwikiLookup()->fetch( $this->mInterwiki );
1916                 if ( $interwiki ) {
1917                         $namespace = $this->getNsText();
1918                         if ( $namespace != '' ) {
1919                                 # Can this actually happen? Interwikis shouldn't be parsed.
1920                                 # Yes! It can in interwiki transclusion. But... it probably shouldn't.
1921                                 $namespace .= ':';
1922                         }
1923                         $url = $interwiki->getURL( $namespace . $this->getDBkey() );
1924                         $url = wfAppendQuery( $url, $query );
1925                 } else {
1926                         $dbkey = wfUrlencode( $this->getPrefixedDBkey() );
1927                         if ( $query == '' ) {
1928                                 $url = str_replace( '$1', $dbkey, $wgArticlePath );
1929                                 // Avoid PHP 7.1 warning from passing $this by reference
1930                                 $titleRef = $this;
1931                                 Hooks::run( 'GetLocalURL::Article', [ &$titleRef, &$url ] );
1932                         } else {
1933                                 global $wgVariantArticlePath, $wgActionPaths, $wgContLang;
1934                                 $url = false;
1935                                 $matches = [];
1936
1937                                 if ( !empty( $wgActionPaths )
1938                                         && preg_match( '/^(.*&|)action=([^&]*)(&(.*)|)$/', $query, $matches )
1939                                 ) {
1940                                         $action = urldecode( $matches[2] );
1941                                         if ( isset( $wgActionPaths[$action] ) ) {
1942                                                 $query = $matches[1];
1943                                                 if ( isset( $matches[4] ) ) {
1944                                                         $query .= $matches[4];
1945                                                 }
1946                                                 $url = str_replace( '$1', $dbkey, $wgActionPaths[$action] );
1947                                                 if ( $query != '' ) {
1948                                                         $url = wfAppendQuery( $url, $query );
1949                                                 }
1950                                         }
1951                                 }
1952
1953                                 if ( $url === false
1954                                         && $wgVariantArticlePath
1955                                         && preg_match( '/^variant=([^&]*)$/', $query, $matches )
1956                                         && $this->getPageLanguage()->equals( $wgContLang )
1957                                         && $this->getPageLanguage()->hasVariants()
1958                                 ) {
1959                                         $variant = urldecode( $matches[1] );
1960                                         if ( $this->getPageLanguage()->hasVariant( $variant ) ) {
1961                                                 // Only do the variant replacement if the given variant is a valid
1962                                                 // variant for the page's language.
1963                                                 $url = str_replace( '$2', urlencode( $variant ), $wgVariantArticlePath );
1964                                                 $url = str_replace( '$1', $dbkey, $url );
1965                                         }
1966                                 }
1967
1968                                 if ( $url === false ) {
1969                                         if ( $query == '-' ) {
1970                                                 $query = '';
1971                                         }
1972                                         $url = "{$wgScript}?title={$dbkey}&{$query}";
1973                                 }
1974                         }
1975                         // Avoid PHP 7.1 warning from passing $this by reference
1976                         $titleRef = $this;
1977                         Hooks::run( 'GetLocalURL::Internal', [ &$titleRef, &$url, $query ] );
1978
1979                         // @todo FIXME: This causes breakage in various places when we
1980                         // actually expected a local URL and end up with dupe prefixes.
1981                         if ( $wgRequest->getVal( 'action' ) == 'render' ) {
1982                                 $url = $wgServer . $url;
1983                         }
1984                 }
1985                 // Avoid PHP 7.1 warning from passing $this by reference
1986                 $titleRef = $this;
1987                 Hooks::run( 'GetLocalURL', [ &$titleRef, &$url, $query ] );
1988                 return $url;
1989         }
1990
1991         /**
1992          * Get a URL that's the simplest URL that will be valid to link, locally,
1993          * to the current Title.  It includes the fragment, but does not include
1994          * the server unless action=render is used (or the link is external).  If
1995          * there's a fragment but the prefixed text is empty, we just return a link
1996          * to the fragment.
1997          *
1998          * The result obviously should not be URL-escaped, but does need to be
1999          * HTML-escaped if it's being output in HTML.
2000          *
2001          * @param string|string[] $query
2002          * @param bool $query2
2003          * @param string|int|bool $proto A PROTO_* constant on how the URL should be expanded,
2004          *                               or false (default) for no expansion
2005          * @see self::getLocalURL for the arguments.
2006          * @return string The URL
2007          */
2008         public function getLinkURL( $query = '', $query2 = false, $proto = false ) {
2009                 if ( $this->isExternal() || $proto !== false ) {
2010                         $ret = $this->getFullURL( $query, $query2, $proto );
2011                 } elseif ( $this->getPrefixedText() === '' && $this->hasFragment() ) {
2012                         $ret = $this->getFragmentForURL();
2013                 } else {
2014                         $ret = $this->getLocalURL( $query, $query2 ) . $this->getFragmentForURL();
2015                 }
2016                 return $ret;
2017         }
2018
2019         /**
2020          * Get the URL form for an internal link.
2021          * - Used in various CDN-related code, in case we have a different
2022          * internal hostname for the server from the exposed one.
2023          *
2024          * This uses $wgInternalServer to qualify the path, or $wgServer
2025          * if $wgInternalServer is not set. If the server variable used is
2026          * protocol-relative, the URL will be expanded to http://
2027          *
2028          * @see self::getLocalURL for the arguments.
2029          * @param string $query
2030          * @param string|bool $query2
2031          * @return string The URL
2032          */
2033         public function getInternalURL( $query = '', $query2 = false ) {
2034                 global $wgInternalServer, $wgServer;
2035                 $query = self::fixUrlQueryArgs( $query, $query2 );
2036                 $server = $wgInternalServer !== false ? $wgInternalServer : $wgServer;
2037                 $url = wfExpandUrl( $server . $this->getLocalURL( $query ), PROTO_HTTP );
2038                 // Avoid PHP 7.1 warning from passing $this by reference
2039                 $titleRef = $this;
2040                 Hooks::run( 'GetInternalURL', [ &$titleRef, &$url, $query ] );
2041                 return $url;
2042         }
2043
2044         /**
2045          * Get the URL for a canonical link, for use in things like IRC and
2046          * e-mail notifications. Uses $wgCanonicalServer and the
2047          * GetCanonicalURL hook.
2048          *
2049          * NOTE: Unlike getInternalURL(), the canonical URL includes the fragment
2050          *
2051          * @see self::getLocalURL for the arguments.
2052          * @param string $query
2053          * @param string|bool $query2
2054          * @return string The URL
2055          * @since 1.18
2056          */
2057         public function getCanonicalURL( $query = '', $query2 = false ) {
2058                 $query = self::fixUrlQueryArgs( $query, $query2 );
2059                 $url = wfExpandUrl( $this->getLocalURL( $query ) . $this->getFragmentForURL(), PROTO_CANONICAL );
2060                 // Avoid PHP 7.1 warning from passing $this by reference
2061                 $titleRef = $this;
2062                 Hooks::run( 'GetCanonicalURL', [ &$titleRef, &$url, $query ] );
2063                 return $url;
2064         }
2065
2066         /**
2067          * Get the edit URL for this Title
2068          *
2069          * @return string The URL, or a null string if this is an interwiki link
2070          */
2071         public function getEditURL() {
2072                 if ( $this->isExternal() ) {
2073                         return '';
2074                 }
2075                 $s = $this->getLocalURL( 'action=edit' );
2076
2077                 return $s;
2078         }
2079
2080         /**
2081          * Can $user perform $action on this page?
2082          * This skips potentially expensive cascading permission checks
2083          * as well as avoids expensive error formatting
2084          *
2085          * Suitable for use for nonessential UI controls in common cases, but
2086          * _not_ for functional access control.
2087          *
2088          * May provide false positives, but should never provide a false negative.
2089          *
2090          * @param string $action Action that permission needs to be checked for
2091          * @param User $user User to check (since 1.19); $wgUser will be used if not provided.
2092          * @return bool
2093          */
2094         public function quickUserCan( $action, $user = null ) {
2095                 return $this->userCan( $action, $user, false );
2096         }
2097
2098         /**
2099          * Can $user perform $action on this page?
2100          *
2101          * @param string $action Action that permission needs to be checked for
2102          * @param User $user User to check (since 1.19); $wgUser will be used if not
2103          *   provided.
2104          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2105          * @return bool
2106          */
2107         public function userCan( $action, $user = null, $rigor = 'secure' ) {
2108                 if ( !$user instanceof User ) {
2109                         global $wgUser;
2110                         $user = $wgUser;
2111                 }
2112
2113                 return !count( $this->getUserPermissionsErrorsInternal( $action, $user, $rigor, true ) );
2114         }
2115
2116         /**
2117          * Can $user perform $action on this page?
2118          *
2119          * @todo FIXME: This *does not* check throttles (User::pingLimiter()).
2120          *
2121          * @param string $action Action that permission needs to be checked for
2122          * @param User $user User to check
2123          * @param string $rigor One of (quick,full,secure)
2124          *   - quick  : does cheap permission checks from replica DBs (usable for GUI creation)
2125          *   - full   : does cheap and expensive checks possibly from a replica DB
2126          *   - secure : does cheap and expensive checks, using the master as needed
2127          * @param array $ignoreErrors Array of Strings Set this to a list of message keys
2128          *   whose corresponding errors may be ignored.
2129          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
2130          */
2131         public function getUserPermissionsErrors(
2132                 $action, $user, $rigor = 'secure', $ignoreErrors = []
2133         ) {
2134                 $errors = $this->getUserPermissionsErrorsInternal( $action, $user, $rigor );
2135
2136                 // Remove the errors being ignored.
2137                 foreach ( $errors as $index => $error ) {
2138                         $errKey = is_array( $error ) ? $error[0] : $error;
2139
2140                         if ( in_array( $errKey, $ignoreErrors ) ) {
2141                                 unset( $errors[$index] );
2142                         }
2143                         if ( $errKey instanceof MessageSpecifier && in_array( $errKey->getKey(), $ignoreErrors ) ) {
2144                                 unset( $errors[$index] );
2145                         }
2146                 }
2147
2148                 return $errors;
2149         }
2150
2151         /**
2152          * Permissions checks that fail most often, and which are easiest to test.
2153          *
2154          * @param string $action The action to check
2155          * @param User $user User to check
2156          * @param array $errors List of current errors
2157          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2158          * @param bool $short Short circuit on first error
2159          *
2160          * @return array List of errors
2161          */
2162         private function checkQuickPermissions( $action, $user, $errors, $rigor, $short ) {
2163                 if ( !Hooks::run( 'TitleQuickPermissions',
2164                         [ $this, $user, $action, &$errors, ( $rigor !== 'quick' ), $short ] )
2165                 ) {
2166                         return $errors;
2167                 }
2168
2169                 if ( $action == 'create' ) {
2170                         if (
2171                                 ( $this->isTalkPage() && !$user->isAllowed( 'createtalk' ) ) ||
2172                                 ( !$this->isTalkPage() && !$user->isAllowed( 'createpage' ) )
2173                         ) {
2174                                 $errors[] = $user->isAnon() ? [ 'nocreatetext' ] : [ 'nocreate-loggedin' ];
2175                         }
2176                 } elseif ( $action == 'move' ) {
2177                         if ( !$user->isAllowed( 'move-rootuserpages' )
2178                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
2179                                 // Show user page-specific message only if the user can move other pages
2180                                 $errors[] = [ 'cant-move-user-page' ];
2181                         }
2182
2183                         // Check if user is allowed to move files if it's a file
2184                         if ( $this->mNamespace == NS_FILE && !$user->isAllowed( 'movefile' ) ) {
2185                                 $errors[] = [ 'movenotallowedfile' ];
2186                         }
2187
2188                         // Check if user is allowed to move category pages if it's a category page
2189                         if ( $this->mNamespace == NS_CATEGORY && !$user->isAllowed( 'move-categorypages' ) ) {
2190                                 $errors[] = [ 'cant-move-category-page' ];
2191                         }
2192
2193                         if ( !$user->isAllowed( 'move' ) ) {
2194                                 // User can't move anything
2195                                 $userCanMove = User::groupHasPermission( 'user', 'move' );
2196                                 $autoconfirmedCanMove = User::groupHasPermission( 'autoconfirmed', 'move' );
2197                                 if ( $user->isAnon() && ( $userCanMove || $autoconfirmedCanMove ) ) {
2198                                         // custom message if logged-in users without any special rights can move
2199                                         $errors[] = [ 'movenologintext' ];
2200                                 } else {
2201                                         $errors[] = [ 'movenotallowed' ];
2202                                 }
2203                         }
2204                 } elseif ( $action == 'move-target' ) {
2205                         if ( !$user->isAllowed( 'move' ) ) {
2206                                 // User can't move anything
2207                                 $errors[] = [ 'movenotallowed' ];
2208                         } elseif ( !$user->isAllowed( 'move-rootuserpages' )
2209                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
2210                                 // Show user page-specific message only if the user can move other pages
2211                                 $errors[] = [ 'cant-move-to-user-page' ];
2212                         } elseif ( !$user->isAllowed( 'move-categorypages' )
2213                                         && $this->mNamespace == NS_CATEGORY ) {
2214                                 // Show category page-specific message only if the user can move other pages
2215                                 $errors[] = [ 'cant-move-to-category-page' ];
2216                         }
2217                 } elseif ( !$user->isAllowed( $action ) ) {
2218                         $errors[] = $this->missingPermissionError( $action, $short );
2219                 }
2220
2221                 return $errors;
2222         }
2223
2224         /**
2225          * Add the resulting error code to the errors array
2226          *
2227          * @param array $errors List of current errors
2228          * @param array $result Result of errors
2229          *
2230          * @return array List of errors
2231          */
2232         private function resultToError( $errors, $result ) {
2233                 if ( is_array( $result ) && count( $result ) && !is_array( $result[0] ) ) {
2234                         // A single array representing an error
2235                         $errors[] = $result;
2236                 } elseif ( is_array( $result ) && is_array( $result[0] ) ) {
2237                         // A nested array representing multiple errors
2238                         $errors = array_merge( $errors, $result );
2239                 } elseif ( $result !== '' && is_string( $result ) ) {
2240                         // A string representing a message-id
2241                         $errors[] = [ $result ];
2242                 } elseif ( $result instanceof MessageSpecifier ) {
2243                         // A message specifier representing an error
2244                         $errors[] = [ $result ];
2245                 } elseif ( $result === false ) {
2246                         // a generic "We don't want them to do that"
2247                         $errors[] = [ 'badaccess-group0' ];
2248                 }
2249                 return $errors;
2250         }
2251
2252         /**
2253          * Check various permission hooks
2254          *
2255          * @param string $action The action to check
2256          * @param User $user User to check
2257          * @param array $errors List of current errors
2258          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2259          * @param bool $short Short circuit on first error
2260          *
2261          * @return array List of errors
2262          */
2263         private function checkPermissionHooks( $action, $user, $errors, $rigor, $short ) {
2264                 // Use getUserPermissionsErrors instead
2265                 $result = '';
2266                 // Avoid PHP 7.1 warning from passing $this by reference
2267                 $titleRef = $this;
2268                 if ( !Hooks::run( 'userCan', [ &$titleRef, &$user, $action, &$result ] ) ) {
2269                         return $result ? [] : [ [ 'badaccess-group0' ] ];
2270                 }
2271                 // Check getUserPermissionsErrors hook
2272                 // Avoid PHP 7.1 warning from passing $this by reference
2273                 $titleRef = $this;
2274                 if ( !Hooks::run( 'getUserPermissionsErrors', [ &$titleRef, &$user, $action, &$result ] ) ) {
2275                         $errors = $this->resultToError( $errors, $result );
2276                 }
2277                 // Check getUserPermissionsErrorsExpensive hook
2278                 if (
2279                         $rigor !== 'quick'
2280                         && !( $short && count( $errors ) > 0 )
2281                         && !Hooks::run( 'getUserPermissionsErrorsExpensive', [ &$titleRef, &$user, $action, &$result ] )
2282                 ) {
2283                         $errors = $this->resultToError( $errors, $result );
2284                 }
2285
2286                 return $errors;
2287         }
2288
2289         /**
2290          * Check permissions on special pages & namespaces
2291          *
2292          * @param string $action The action to check
2293          * @param User $user User to check
2294          * @param array $errors List of current errors
2295          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2296          * @param bool $short Short circuit on first error
2297          *
2298          * @return array List of errors
2299          */
2300         private function checkSpecialsAndNSPermissions( $action, $user, $errors, $rigor, $short ) {
2301                 # Only 'createaccount' can be performed on special pages,
2302                 # which don't actually exist in the DB.
2303                 if ( $this->isSpecialPage() && $action !== 'createaccount' ) {
2304                         $errors[] = [ 'ns-specialprotected' ];
2305                 }
2306
2307                 # Check $wgNamespaceProtection for restricted namespaces
2308                 if ( $this->isNamespaceProtected( $user ) ) {
2309                         $ns = $this->mNamespace == NS_MAIN ?
2310                                 wfMessage( 'nstab-main' )->text() : $this->getNsText();
2311                         $errors[] = $this->mNamespace == NS_MEDIAWIKI ?
2312                                 [ 'protectedinterface', $action ] : [ 'namespaceprotected', $ns, $action ];
2313                 }
2314
2315                 return $errors;
2316         }
2317
2318         /**
2319          * Check CSS/JS sub-page permissions
2320          *
2321          * @param string $action The action to check
2322          * @param User $user User to check
2323          * @param array $errors List of current errors
2324          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2325          * @param bool $short Short circuit on first error
2326          *
2327          * @return array List of errors
2328          */
2329         private function checkUserConfigPermissions( $action, $user, $errors, $rigor, $short ) {
2330                 # Protect css/js subpages of user pages
2331                 # XXX: this might be better using restrictions
2332
2333                 if ( $action != 'patrol' ) {
2334                         if ( preg_match( '/^' . preg_quote( $user->getName(), '/' ) . '\//', $this->mTextform ) ) {
2335                                 if (
2336                                         $this->isUserCssConfigPage()
2337                                         && !$user->isAllowedAny( 'editmyusercss', 'editusercss' )
2338                                 ) {
2339                                         $errors[] = [ 'mycustomcssprotected', $action ];
2340                                 } elseif (
2341                                         $this->isUserJsConfigPage()
2342                                         && !$user->isAllowedAny( 'editmyuserjs', 'edituserjs' )
2343                                 ) {
2344                                         $errors[] = [ 'mycustomjsprotected', $action ];
2345                                 }
2346                         } else {
2347                                 if (
2348                                         $this->isUserCssConfigPage()
2349                                         && !$user->isAllowed( 'editusercss' )
2350                                 ) {
2351                                         $errors[] = [ 'customcssprotected', $action ];
2352                                 } elseif (
2353                                         $this->isUserJsConfigPage()
2354                                         && !$user->isAllowed( 'edituserjs' )
2355                                 ) {
2356                                         $errors[] = [ 'customjsprotected', $action ];
2357                                 }
2358                         }
2359                 }
2360
2361                 return $errors;
2362         }
2363
2364         /**
2365          * Check against page_restrictions table requirements on this
2366          * page. The user must possess all required rights for this
2367          * action.
2368          *
2369          * @param string $action The action to check
2370          * @param User $user User to check
2371          * @param array $errors List of current errors
2372          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2373          * @param bool $short Short circuit on first error
2374          *
2375          * @return array List of errors
2376          */
2377         private function checkPageRestrictions( $action, $user, $errors, $rigor, $short ) {
2378                 foreach ( $this->getRestrictions( $action ) as $right ) {
2379                         // Backwards compatibility, rewrite sysop -> editprotected
2380                         if ( $right == 'sysop' ) {
2381                                 $right = 'editprotected';
2382                         }
2383                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2384                         if ( $right == 'autoconfirmed' ) {
2385                                 $right = 'editsemiprotected';
2386                         }
2387                         if ( $right == '' ) {
2388                                 continue;
2389                         }
2390                         if ( !$user->isAllowed( $right ) ) {
2391                                 $errors[] = [ 'protectedpagetext', $right, $action ];
2392                         } elseif ( $this->mCascadeRestriction && !$user->isAllowed( 'protect' ) ) {
2393                                 $errors[] = [ 'protectedpagetext', 'protect', $action ];
2394                         }
2395                 }
2396
2397                 return $errors;
2398         }
2399
2400         /**
2401          * Check restrictions on cascading pages.
2402          *
2403          * @param string $action The action to check
2404          * @param User $user User to check
2405          * @param array $errors List of current errors
2406          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2407          * @param bool $short Short circuit on first error
2408          *
2409          * @return array List of errors
2410          */
2411         private function checkCascadingSourcesRestrictions( $action, $user, $errors, $rigor, $short ) {
2412                 if ( $rigor !== 'quick' && !$this->isUserConfigPage() ) {
2413                         # We /could/ use the protection level on the source page, but it's
2414                         # fairly ugly as we have to establish a precedence hierarchy for pages
2415                         # included by multiple cascade-protected pages. So just restrict
2416                         # it to people with 'protect' permission, as they could remove the
2417                         # protection anyway.
2418                         list( $cascadingSources, $restrictions ) = $this->getCascadeProtectionSources();
2419                         # Cascading protection depends on more than this page...
2420                         # Several cascading protected pages may include this page...
2421                         # Check each cascading level
2422                         # This is only for protection restrictions, not for all actions
2423                         if ( isset( $restrictions[$action] ) ) {
2424                                 foreach ( $restrictions[$action] as $right ) {
2425                                         // Backwards compatibility, rewrite sysop -> editprotected
2426                                         if ( $right == 'sysop' ) {
2427                                                 $right = 'editprotected';
2428                                         }
2429                                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2430                                         if ( $right == 'autoconfirmed' ) {
2431                                                 $right = 'editsemiprotected';
2432                                         }
2433                                         if ( $right != '' && !$user->isAllowedAll( 'protect', $right ) ) {
2434                                                 $pages = '';
2435                                                 foreach ( $cascadingSources as $page ) {
2436                                                         $pages .= '* [[:' . $page->getPrefixedText() . "]]\n";
2437                                                 }
2438                                                 $errors[] = [ 'cascadeprotected', count( $cascadingSources ), $pages, $action ];
2439                                         }
2440                                 }
2441                         }
2442                 }
2443
2444                 return $errors;
2445         }
2446
2447         /**
2448          * Check action permissions not already checked in checkQuickPermissions
2449          *
2450          * @param string $action The action to check
2451          * @param User $user User to check
2452          * @param array $errors List of current errors
2453          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2454          * @param bool $short Short circuit on first error
2455          *
2456          * @return array List of errors
2457          */
2458         private function checkActionPermissions( $action, $user, $errors, $rigor, $short ) {
2459                 global $wgDeleteRevisionsLimit, $wgLang;
2460
2461                 if ( $action == 'protect' ) {
2462                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit', $user, $rigor, true ) ) ) {
2463                                 // If they can't edit, they shouldn't protect.
2464                                 $errors[] = [ 'protect-cantedit' ];
2465                         }
2466                 } elseif ( $action == 'create' ) {
2467                         $title_protection = $this->getTitleProtection();
2468                         if ( $title_protection ) {
2469                                 if ( $title_protection['permission'] == ''
2470                                         || !$user->isAllowed( $title_protection['permission'] )
2471                                 ) {
2472                                         $errors[] = [
2473                                                 'titleprotected',
2474                                                 User::whoIs( $title_protection['user'] ),
2475                                                 $title_protection['reason']
2476                                         ];
2477                                 }
2478                         }
2479                 } elseif ( $action == 'move' ) {
2480                         // Check for immobile pages
2481                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2482                                 // Specific message for this case
2483                                 $errors[] = [ 'immobile-source-namespace', $this->getNsText() ];
2484                         } elseif ( !$this->isMovable() ) {
2485                                 // Less specific message for rarer cases
2486                                 $errors[] = [ 'immobile-source-page' ];
2487                         }
2488                 } elseif ( $action == 'move-target' ) {
2489                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2490                                 $errors[] = [ 'immobile-target-namespace', $this->getNsText() ];
2491                         } elseif ( !$this->isMovable() ) {
2492                                 $errors[] = [ 'immobile-target-page' ];
2493                         }
2494                 } elseif ( $action == 'delete' ) {
2495                         $tempErrors = $this->checkPageRestrictions( 'edit', $user, [], $rigor, true );
2496                         if ( !$tempErrors ) {
2497                                 $tempErrors = $this->checkCascadingSourcesRestrictions( 'edit',
2498                                         $user, $tempErrors, $rigor, true );
2499                         }
2500                         if ( $tempErrors ) {
2501                                 // If protection keeps them from editing, they shouldn't be able to delete.
2502                                 $errors[] = [ 'deleteprotected' ];
2503                         }
2504                         if ( $rigor !== 'quick' && $wgDeleteRevisionsLimit
2505                                 && !$this->userCan( 'bigdelete', $user ) && $this->isBigDeletion()
2506                         ) {
2507                                 $errors[] = [ 'delete-toobig', $wgLang->formatNum( $wgDeleteRevisionsLimit ) ];
2508                         }
2509                 } elseif ( $action === 'undelete' ) {
2510                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit', $user, $rigor, true ) ) ) {
2511                                 // Undeleting implies editing
2512                                 $errors[] = [ 'undelete-cantedit' ];
2513                         }
2514                         if ( !$this->exists()
2515                                 && count( $this->getUserPermissionsErrorsInternal( 'create', $user, $rigor, true ) )
2516                         ) {
2517                                 // Undeleting where nothing currently exists implies creating
2518                                 $errors[] = [ 'undelete-cantcreate' ];
2519                         }
2520                 }
2521                 return $errors;
2522         }
2523
2524         /**
2525          * Check that the user isn't blocked from editing.
2526          *
2527          * @param string $action The action to check
2528          * @param User $user User to check
2529          * @param array $errors List of current errors
2530          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2531          * @param bool $short Short circuit on first error
2532          *
2533          * @return array List of errors
2534          */
2535         private function checkUserBlock( $action, $user, $errors, $rigor, $short ) {
2536                 global $wgEmailConfirmToEdit, $wgBlockDisablesLogin;
2537                 // Account creation blocks handled at userlogin.
2538                 // Unblocking handled in SpecialUnblock
2539                 if ( $rigor === 'quick' || in_array( $action, [ 'createaccount', 'unblock' ] ) ) {
2540                         return $errors;
2541                 }
2542
2543                 // Optimize for a very common case
2544                 if ( $action === 'read' && !$wgBlockDisablesLogin ) {
2545                         return $errors;
2546                 }
2547
2548                 if ( $wgEmailConfirmToEdit && !$user->isEmailConfirmed() ) {
2549                         $errors[] = [ 'confirmedittext' ];
2550                 }
2551
2552                 $useSlave = ( $rigor !== 'secure' );
2553                 if ( ( $action == 'edit' || $action == 'create' )
2554                         && !$user->isBlockedFrom( $this, $useSlave )
2555                 ) {
2556                         // Don't block the user from editing their own talk page unless they've been
2557                         // explicitly blocked from that too.
2558                 } elseif ( $user->isBlocked() && $user->getBlock()->prevents( $action ) !== false ) {
2559                         // @todo FIXME: Pass the relevant context into this function.
2560                         $errors[] = $user->getBlock()->getPermissionsError( RequestContext::getMain() );
2561                 }
2562
2563                 return $errors;
2564         }
2565
2566         /**
2567          * Check that the user is allowed to read this page.
2568          *
2569          * @param string $action The action to check
2570          * @param User $user User to check
2571          * @param array $errors List of current errors
2572          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2573          * @param bool $short Short circuit on first error
2574          *
2575          * @return array List of errors
2576          */
2577         private function checkReadPermissions( $action, $user, $errors, $rigor, $short ) {
2578                 global $wgWhitelistRead, $wgWhitelistReadRegexp;
2579
2580                 $whitelisted = false;
2581                 if ( User::isEveryoneAllowed( 'read' ) ) {
2582                         # Shortcut for public wikis, allows skipping quite a bit of code
2583                         $whitelisted = true;
2584                 } elseif ( $user->isAllowed( 'read' ) ) {
2585                         # If the user is allowed to read pages, he is allowed to read all pages
2586                         $whitelisted = true;
2587                 } elseif ( $this->isSpecial( 'Userlogin' )
2588                         || $this->isSpecial( 'PasswordReset' )
2589                         || $this->isSpecial( 'Userlogout' )
2590                 ) {
2591                         # Always grant access to the login page.
2592                         # Even anons need to be able to log in.
2593                         $whitelisted = true;
2594                 } elseif ( is_array( $wgWhitelistRead ) && count( $wgWhitelistRead ) ) {
2595                         # Time to check the whitelist
2596                         # Only do these checks is there's something to check against
2597                         $name = $this->getPrefixedText();
2598                         $dbName = $this->getPrefixedDBkey();
2599
2600                         // Check for explicit whitelisting with and without underscores
2601                         if ( in_array( $name, $wgWhitelistRead, true ) || in_array( $dbName, $wgWhitelistRead, true ) ) {
2602                                 $whitelisted = true;
2603                         } elseif ( $this->getNamespace() == NS_MAIN ) {
2604                                 # Old settings might have the title prefixed with
2605                                 # a colon for main-namespace pages
2606                                 if ( in_array( ':' . $name, $wgWhitelistRead ) ) {
2607                                         $whitelisted = true;
2608                                 }
2609                         } elseif ( $this->isSpecialPage() ) {
2610                                 # If it's a special page, ditch the subpage bit and check again
2611                                 $name = $this->getDBkey();
2612                                 list( $name, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $name );
2613                                 if ( $name ) {
2614                                         $pure = SpecialPage::getTitleFor( $name )->getPrefixedText();
2615                                         if ( in_array( $pure, $wgWhitelistRead, true ) ) {
2616                                                 $whitelisted = true;
2617                                         }
2618                                 }
2619                         }
2620                 }
2621
2622                 if ( !$whitelisted && is_array( $wgWhitelistReadRegexp ) && !empty( $wgWhitelistReadRegexp ) ) {
2623                         $name = $this->getPrefixedText();
2624                         // Check for regex whitelisting
2625                         foreach ( $wgWhitelistReadRegexp as $listItem ) {
2626                                 if ( preg_match( $listItem, $name ) ) {
2627                                         $whitelisted = true;
2628                                         break;
2629                                 }
2630                         }
2631                 }
2632
2633                 if ( !$whitelisted ) {
2634                         # If the title is not whitelisted, give extensions a chance to do so...
2635                         Hooks::run( 'TitleReadWhitelist', [ $this, $user, &$whitelisted ] );
2636                         if ( !$whitelisted ) {
2637                                 $errors[] = $this->missingPermissionError( $action, $short );
2638                         }
2639                 }
2640
2641                 return $errors;
2642         }
2643
2644         /**
2645          * Get a description array when the user doesn't have the right to perform
2646          * $action (i.e. when User::isAllowed() returns false)
2647          *
2648          * @param string $action The action to check
2649          * @param bool $short Short circuit on first error
2650          * @return array Array containing an error message key and any parameters
2651          */
2652         private function missingPermissionError( $action, $short ) {
2653                 // We avoid expensive display logic for quickUserCan's and such
2654                 if ( $short ) {
2655                         return [ 'badaccess-group0' ];
2656                 }
2657
2658                 return User::newFatalPermissionDeniedStatus( $action )->getErrorsArray()[0];
2659         }
2660
2661         /**
2662          * Can $user perform $action on this page? This is an internal function,
2663          * with multiple levels of checks depending on performance needs; see $rigor below.
2664          * It does not check wfReadOnly().
2665          *
2666          * @param string $action Action that permission needs to be checked for
2667          * @param User $user User to check
2668          * @param string $rigor One of (quick,full,secure)
2669          *   - quick  : does cheap permission checks from replica DBs (usable for GUI creation)
2670          *   - full   : does cheap and expensive checks possibly from a replica DB
2671          *   - secure : does cheap and expensive checks, using the master as needed
2672          * @param bool $short Set this to true to stop after the first permission error.
2673          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
2674          */
2675         protected function getUserPermissionsErrorsInternal(
2676                 $action, $user, $rigor = 'secure', $short = false
2677         ) {
2678                 if ( $rigor === true ) {
2679                         $rigor = 'secure'; // b/c
2680                 } elseif ( $rigor === false ) {
2681                         $rigor = 'quick'; // b/c
2682                 } elseif ( !in_array( $rigor, [ 'quick', 'full', 'secure' ] ) ) {
2683                         throw new Exception( "Invalid rigor parameter '$rigor'." );
2684                 }
2685
2686                 # Read has special handling
2687                 if ( $action == 'read' ) {
2688                         $checks = [
2689                                 'checkPermissionHooks',
2690                                 'checkReadPermissions',
2691                                 'checkUserBlock', // for wgBlockDisablesLogin
2692                         ];
2693                 # Don't call checkSpecialsAndNSPermissions or checkUserConfigPermissions
2694                 # here as it will lead to duplicate error messages. This is okay to do
2695                 # since anywhere that checks for create will also check for edit, and
2696                 # those checks are called for edit.
2697                 } elseif ( $action == 'create' ) {
2698                         $checks = [
2699                                 'checkQuickPermissions',
2700                                 'checkPermissionHooks',
2701                                 'checkPageRestrictions',
2702                                 'checkCascadingSourcesRestrictions',
2703                                 'checkActionPermissions',
2704                                 'checkUserBlock'
2705                         ];
2706                 } else {
2707                         $checks = [
2708                                 'checkQuickPermissions',
2709                                 'checkPermissionHooks',
2710                                 'checkSpecialsAndNSPermissions',
2711                                 'checkUserConfigPermissions',
2712                                 'checkPageRestrictions',
2713                                 'checkCascadingSourcesRestrictions',
2714                                 'checkActionPermissions',
2715                                 'checkUserBlock'
2716                         ];
2717                 }
2718
2719                 $errors = [];
2720                 while ( count( $checks ) > 0 &&
2721                                 !( $short && count( $errors ) > 0 ) ) {
2722                         $method = array_shift( $checks );
2723                         $errors = $this->$method( $action, $user, $errors, $rigor, $short );
2724                 }
2725
2726                 return $errors;
2727         }
2728
2729         /**
2730          * Get a filtered list of all restriction types supported by this wiki.
2731          * @param bool $exists True to get all restriction types that apply to
2732          * titles that do exist, False for all restriction types that apply to
2733          * titles that do not exist
2734          * @return array
2735          */
2736         public static function getFilteredRestrictionTypes( $exists = true ) {
2737                 global $wgRestrictionTypes;
2738                 $types = $wgRestrictionTypes;
2739                 if ( $exists ) {
2740                         # Remove the create restriction for existing titles
2741                         $types = array_diff( $types, [ 'create' ] );
2742                 } else {
2743                         # Only the create and upload restrictions apply to non-existing titles
2744                         $types = array_intersect( $types, [ 'create', 'upload' ] );
2745                 }
2746                 return $types;
2747         }
2748
2749         /**
2750          * Returns restriction types for the current Title
2751          *
2752          * @return array Applicable restriction types
2753          */
2754         public function getRestrictionTypes() {
2755                 if ( $this->isSpecialPage() ) {
2756                         return [];
2757                 }
2758
2759                 $types = self::getFilteredRestrictionTypes( $this->exists() );
2760
2761                 if ( $this->getNamespace() != NS_FILE ) {
2762                         # Remove the upload restriction for non-file titles
2763                         $types = array_diff( $types, [ 'upload' ] );
2764                 }
2765
2766                 Hooks::run( 'TitleGetRestrictionTypes', [ $this, &$types ] );
2767
2768                 wfDebug( __METHOD__ . ': applicable restrictions to [[' .
2769                         $this->getPrefixedText() . ']] are {' . implode( ',', $types ) . "}\n" );
2770
2771                 return $types;
2772         }
2773
2774         /**
2775          * Is this title subject to title protection?
2776          * Title protection is the one applied against creation of such title.
2777          *
2778          * @return array|bool An associative array representing any existent title
2779          *   protection, or false if there's none.
2780          */
2781         public function getTitleProtection() {
2782                 $protection = $this->getTitleProtectionInternal();
2783                 if ( $protection ) {
2784                         if ( $protection['permission'] == 'sysop' ) {
2785                                 $protection['permission'] = 'editprotected'; // B/C
2786                         }
2787                         if ( $protection['permission'] == 'autoconfirmed' ) {
2788                                 $protection['permission'] = 'editsemiprotected'; // B/C
2789                         }
2790                 }
2791                 return $protection;
2792         }
2793
2794         /**
2795          * Fetch title protection settings
2796          *
2797          * To work correctly, $this->loadRestrictions() needs to have access to the
2798          * actual protections in the database without munging 'sysop' =>
2799          * 'editprotected' and 'autoconfirmed' => 'editsemiprotected'. Other
2800          * callers probably want $this->getTitleProtection() instead.
2801          *
2802          * @return array|bool
2803          */
2804         protected function getTitleProtectionInternal() {
2805                 // Can't protect pages in special namespaces
2806                 if ( $this->getNamespace() < 0 ) {
2807                         return false;
2808                 }
2809
2810                 // Can't protect pages that exist.
2811                 if ( $this->exists() ) {
2812                         return false;
2813                 }
2814
2815                 if ( $this->mTitleProtection === null ) {
2816                         $dbr = wfGetDB( DB_REPLICA );
2817                         $commentStore = CommentStore::getStore();
2818                         $commentQuery = $commentStore->getJoin( 'pt_reason' );
2819                         $res = $dbr->select(
2820                                 [ 'protected_titles' ] + $commentQuery['tables'],
2821                                 [
2822                                         'user' => 'pt_user',
2823                                         'expiry' => 'pt_expiry',
2824                                         'permission' => 'pt_create_perm'
2825                                 ] + $commentQuery['fields'],
2826                                 [ 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ],
2827                                 __METHOD__,
2828                                 [],
2829                                 $commentQuery['joins']
2830                         );
2831
2832                         // fetchRow returns false if there are no rows.
2833                         $row = $dbr->fetchRow( $res );
2834                         if ( $row ) {
2835                                 $this->mTitleProtection = [
2836                                         'user' => $row['user'],
2837                                         'expiry' => $dbr->decodeExpiry( $row['expiry'] ),
2838                                         'permission' => $row['permission'],
2839                                         'reason' => $commentStore->getComment( 'pt_reason', $row )->text,
2840                                 ];
2841                         } else {
2842                                 $this->mTitleProtection = false;
2843                         }
2844                 }
2845                 return $this->mTitleProtection;
2846         }
2847
2848         /**
2849          * Remove any title protection due to page existing
2850          */
2851         public function deleteTitleProtection() {
2852                 $dbw = wfGetDB( DB_MASTER );
2853
2854                 $dbw->delete(
2855                         'protected_titles',
2856                         [ 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ],
2857                         __METHOD__
2858                 );
2859                 $this->mTitleProtection = false;
2860         }
2861
2862         /**
2863          * Is this page "semi-protected" - the *only* protection levels are listed
2864          * in $wgSemiprotectedRestrictionLevels?
2865          *
2866          * @param string $action Action to check (default: edit)
2867          * @return bool
2868          */
2869         public function isSemiProtected( $action = 'edit' ) {
2870                 global $wgSemiprotectedRestrictionLevels;
2871
2872                 $restrictions = $this->getRestrictions( $action );
2873                 $semi = $wgSemiprotectedRestrictionLevels;
2874                 if ( !$restrictions || !$semi ) {
2875                         // Not protected, or all protection is full protection
2876                         return false;
2877                 }
2878
2879                 // Remap autoconfirmed to editsemiprotected for BC
2880                 foreach ( array_keys( $semi, 'autoconfirmed' ) as $key ) {
2881                         $semi[$key] = 'editsemiprotected';
2882                 }
2883                 foreach ( array_keys( $restrictions, 'autoconfirmed' ) as $key ) {
2884                         $restrictions[$key] = 'editsemiprotected';
2885                 }
2886
2887                 return !array_diff( $restrictions, $semi );
2888         }
2889
2890         /**
2891          * Does the title correspond to a protected article?
2892          *
2893          * @param string $action The action the page is protected from,
2894          * by default checks all actions.
2895          * @return bool
2896          */
2897         public function isProtected( $action = '' ) {
2898                 global $wgRestrictionLevels;
2899
2900                 $restrictionTypes = $this->getRestrictionTypes();
2901
2902                 # Special pages have inherent protection
2903                 if ( $this->isSpecialPage() ) {
2904                         return true;
2905                 }
2906
2907                 # Check regular protection levels
2908                 foreach ( $restrictionTypes as $type ) {
2909                         if ( $action == $type || $action == '' ) {
2910                                 $r = $this->getRestrictions( $type );
2911                                 foreach ( $wgRestrictionLevels as $level ) {
2912                                         if ( in_array( $level, $r ) && $level != '' ) {
2913                                                 return true;
2914                                         }
2915                                 }
2916                         }
2917                 }
2918
2919                 return false;
2920         }
2921
2922         /**
2923          * Determines if $user is unable to edit this page because it has been protected
2924          * by $wgNamespaceProtection.
2925          *
2926          * @param User $user User object to check permissions
2927          * @return bool
2928          */
2929         public function isNamespaceProtected( User $user ) {
2930                 global $wgNamespaceProtection;
2931
2932                 if ( isset( $wgNamespaceProtection[$this->mNamespace] ) ) {
2933                         foreach ( (array)$wgNamespaceProtection[$this->mNamespace] as $right ) {
2934                                 if ( $right != '' && !$user->isAllowed( $right ) ) {
2935                                         return true;
2936                                 }
2937                         }
2938                 }
2939                 return false;
2940         }
2941
2942         /**
2943          * Cascading protection: Return true if cascading restrictions apply to this page, false if not.
2944          *
2945          * @return bool If the page is subject to cascading restrictions.
2946          */
2947         public function isCascadeProtected() {
2948                 list( $sources, /* $restrictions */ ) = $this->getCascadeProtectionSources( false );
2949                 return ( $sources > 0 );
2950         }
2951
2952         /**
2953          * Determines whether cascading protection sources have already been loaded from
2954          * the database.
2955          *
2956          * @param bool $getPages True to check if the pages are loaded, or false to check
2957          * if the status is loaded.
2958          * @return bool Whether or not the specified information has been loaded
2959          * @since 1.23
2960          */
2961         public function areCascadeProtectionSourcesLoaded( $getPages = true ) {
2962                 return $getPages ? $this->mCascadeSources !== null : $this->mHasCascadingRestrictions !== null;
2963         }
2964
2965         /**
2966          * Cascading protection: Get the source of any cascading restrictions on this page.
2967          *
2968          * @param bool $getPages Whether or not to retrieve the actual pages
2969          *        that the restrictions have come from and the actual restrictions
2970          *        themselves.
2971          * @return array Two elements: First is an array of Title objects of the
2972          *        pages from which cascading restrictions have come, false for
2973          *        none, or true if such restrictions exist but $getPages was not
2974          *        set. Second is an array like that returned by
2975          *        Title::getAllRestrictions(), or an empty array if $getPages is
2976          *        false.
2977          */
2978         public function getCascadeProtectionSources( $getPages = true ) {
2979                 $pagerestrictions = [];
2980
2981                 if ( $this->mCascadeSources !== null && $getPages ) {
2982                         return [ $this->mCascadeSources, $this->mCascadingRestrictions ];
2983                 } elseif ( $this->mHasCascadingRestrictions !== null && !$getPages ) {
2984                         return [ $this->mHasCascadingRestrictions, $pagerestrictions ];
2985                 }
2986
2987                 $dbr = wfGetDB( DB_REPLICA );
2988
2989                 if ( $this->getNamespace() == NS_FILE ) {
2990                         $tables = [ 'imagelinks', 'page_restrictions' ];
2991                         $where_clauses = [
2992                                 'il_to' => $this->getDBkey(),
2993                                 'il_from=pr_page',
2994                                 'pr_cascade' => 1
2995                         ];
2996                 } else {
2997                         $tables = [ 'templatelinks', 'page_restrictions' ];
2998                         $where_clauses = [
2999                                 'tl_namespace' => $this->getNamespace(),
3000                                 'tl_title' => $this->getDBkey(),
3001                                 'tl_from=pr_page',
3002                                 'pr_cascade' => 1
3003                         ];
3004                 }
3005
3006                 if ( $getPages ) {
3007                         $cols = [ 'pr_page', 'page_namespace', 'page_title',
3008                                 'pr_expiry', 'pr_type', 'pr_level' ];
3009                         $where_clauses[] = 'page_id=pr_page';
3010                         $tables[] = 'page';
3011                 } else {
3012                         $cols = [ 'pr_expiry' ];
3013                 }
3014
3015                 $res = $dbr->select( $tables, $cols, $where_clauses, __METHOD__ );
3016
3017                 $sources = $getPages ? [] : false;
3018                 $now = wfTimestampNow();
3019
3020                 foreach ( $res as $row ) {
3021                         $expiry = $dbr->decodeExpiry( $row->pr_expiry );
3022                         if ( $expiry > $now ) {
3023                                 if ( $getPages ) {
3024                                         $page_id = $row->pr_page;
3025                                         $page_ns = $row->page_namespace;
3026                                         $page_title = $row->page_title;
3027                                         $sources[$page_id] = self::makeTitle( $page_ns, $page_title );
3028                                         # Add groups needed for each restriction type if its not already there
3029                                         # Make sure this restriction type still exists
3030
3031                                         if ( !isset( $pagerestrictions[$row->pr_type] ) ) {
3032                                                 $pagerestrictions[$row->pr_type] = [];
3033                                         }
3034
3035                                         if (
3036                                                 isset( $pagerestrictions[$row->pr_type] )
3037                                                 && !in_array( $row->pr_level, $pagerestrictions[$row->pr_type] )
3038                                         ) {
3039                                                 $pagerestrictions[$row->pr_type][] = $row->pr_level;
3040                                         }
3041                                 } else {
3042                                         $sources = true;
3043                                 }
3044                         }
3045                 }
3046
3047                 if ( $getPages ) {
3048                         $this->mCascadeSources = $sources;
3049                         $this->mCascadingRestrictions = $pagerestrictions;
3050                 } else {
3051                         $this->mHasCascadingRestrictions = $sources;
3052                 }
3053
3054                 return [ $sources, $pagerestrictions ];
3055         }
3056
3057         /**
3058          * Accessor for mRestrictionsLoaded
3059          *
3060          * @return bool Whether or not the page's restrictions have already been
3061          * loaded from the database
3062          * @since 1.23
3063          */
3064         public function areRestrictionsLoaded() {
3065                 return $this->mRestrictionsLoaded;
3066         }
3067
3068         /**
3069          * Accessor/initialisation for mRestrictions
3070          *
3071          * @param string $action Action that permission needs to be checked for
3072          * @return array Restriction levels needed to take the action. All levels are
3073          *     required. Note that restriction levels are normally user rights, but 'sysop'
3074          *     and 'autoconfirmed' are also allowed for backwards compatibility. These should
3075          *     be mapped to 'editprotected' and 'editsemiprotected' respectively.
3076          */
3077         public function getRestrictions( $action ) {
3078                 if ( !$this->mRestrictionsLoaded ) {
3079                         $this->loadRestrictions();
3080                 }
3081                 return isset( $this->mRestrictions[$action] )
3082                                 ? $this->mRestrictions[$action]
3083                                 : [];
3084         }
3085
3086         /**
3087          * Accessor/initialisation for mRestrictions
3088          *
3089          * @return array Keys are actions, values are arrays as returned by
3090          *     Title::getRestrictions()
3091          * @since 1.23
3092          */
3093         public function getAllRestrictions() {
3094                 if ( !$this->mRestrictionsLoaded ) {
3095                         $this->loadRestrictions();
3096                 }
3097                 return $this->mRestrictions;
3098         }
3099
3100         /**
3101          * Get the expiry time for the restriction against a given action
3102          *
3103          * @param string $action
3104          * @return string|bool 14-char timestamp, or 'infinity' if the page is protected forever
3105          *     or not protected at all, or false if the action is not recognised.
3106          */
3107         public function getRestrictionExpiry( $action ) {
3108                 if ( !$this->mRestrictionsLoaded ) {
3109                         $this->loadRestrictions();
3110                 }
3111                 return isset( $this->mRestrictionsExpiry[$action] ) ? $this->mRestrictionsExpiry[$action] : false;
3112         }
3113
3114         /**
3115          * Returns cascading restrictions for the current article
3116          *
3117          * @return bool
3118          */
3119         function areRestrictionsCascading() {
3120                 if ( !$this->mRestrictionsLoaded ) {
3121                         $this->loadRestrictions();
3122                 }
3123
3124                 return $this->mCascadeRestriction;
3125         }
3126
3127         /**
3128          * Compiles list of active page restrictions from both page table (pre 1.10)
3129          * and page_restrictions table for this existing page.
3130          * Public for usage by LiquidThreads.
3131          *
3132          * @param array $rows Array of db result objects
3133          * @param string $oldFashionedRestrictions Comma-separated set of permission keys
3134          * indicating who can move or edit the page from the page table, (pre 1.10) rows.
3135          * Edit and move sections are separated by a colon
3136          * Example: "edit=autoconfirmed,sysop:move=sysop"
3137          */
3138         public function loadRestrictionsFromRows( $rows, $oldFashionedRestrictions = null ) {
3139                 $dbr = wfGetDB( DB_REPLICA );
3140
3141                 $restrictionTypes = $this->getRestrictionTypes();
3142
3143                 foreach ( $restrictionTypes as $type ) {
3144                         $this->mRestrictions[$type] = [];
3145                         $this->mRestrictionsExpiry[$type] = 'infinity';
3146                 }
3147
3148                 $this->mCascadeRestriction = false;
3149
3150                 # Backwards-compatibility: also load the restrictions from the page record (old format).
3151                 if ( $oldFashionedRestrictions !== null ) {
3152                         $this->mOldRestrictions = $oldFashionedRestrictions;
3153                 }
3154
3155                 if ( $this->mOldRestrictions === false ) {
3156                         $this->mOldRestrictions = $dbr->selectField( 'page', 'page_restrictions',
3157                                 [ 'page_id' => $this->getArticleID() ], __METHOD__ );
3158                 }
3159
3160                 if ( $this->mOldRestrictions != '' ) {
3161                         foreach ( explode( ':', trim( $this->mOldRestrictions ) ) as $restrict ) {
3162                                 $temp = explode( '=', trim( $restrict ) );
3163                                 if ( count( $temp ) == 1 ) {
3164                                         // old old format should be treated as edit/move restriction
3165                                         $this->mRestrictions['edit'] = explode( ',', trim( $temp[0] ) );
3166                                         $this->mRestrictions['move'] = explode( ',', trim( $temp[0] ) );
3167                                 } else {
3168                                         $restriction = trim( $temp[1] );
3169                                         if ( $restriction != '' ) { // some old entries are empty
3170                                                 $this->mRestrictions[$temp[0]] = explode( ',', $restriction );
3171                                         }
3172                                 }
3173                         }
3174                 }
3175
3176                 if ( count( $rows ) ) {
3177                         # Current system - load second to make them override.
3178                         $now = wfTimestampNow();
3179
3180                         # Cycle through all the restrictions.
3181                         foreach ( $rows as $row ) {
3182                                 // Don't take care of restrictions types that aren't allowed
3183                                 if ( !in_array( $row->pr_type, $restrictionTypes ) ) {
3184                                         continue;
3185                                 }
3186
3187                                 $expiry = $dbr->decodeExpiry( $row->pr_expiry );
3188
3189                                 // Only apply the restrictions if they haven't expired!
3190                                 if ( !$expiry || $expiry > $now ) {
3191                                         $this->mRestrictionsExpiry[$row->pr_type] = $expiry;
3192                                         $this->mRestrictions[$row->pr_type] = explode( ',', trim( $row->pr_level ) );
3193
3194                                         $this->mCascadeRestriction |= $row->pr_cascade;
3195                                 }
3196                         }
3197                 }
3198
3199                 $this->mRestrictionsLoaded = true;
3200         }
3201
3202         /**
3203          * Load restrictions from the page_restrictions table
3204          *
3205          * @param string $oldFashionedRestrictions Comma-separated set of permission keys
3206          * indicating who can move or edit the page from the page table, (pre 1.10) rows.
3207          * Edit and move sections are separated by a colon
3208          * Example: "edit=autoconfirmed,sysop:move=sysop"
3209          */
3210         public function loadRestrictions( $oldFashionedRestrictions = null ) {
3211                 if ( $this->mRestrictionsLoaded ) {
3212                         return;
3213                 }
3214
3215                 $id = $this->getArticleID();
3216                 if ( $id ) {
3217                         $cache = ObjectCache::getMainWANInstance();
3218                         $rows = $cache->getWithSetCallback(
3219                                 // Page protections always leave a new null revision
3220                                 $cache->makeKey( 'page-restrictions', $id, $this->getLatestRevID() ),
3221                                 $cache::TTL_DAY,
3222                                 function ( $curValue, &$ttl, array &$setOpts ) {
3223                                         $dbr = wfGetDB( DB_REPLICA );
3224
3225                                         $setOpts += Database::getCacheSetOptions( $dbr );
3226
3227                                         return iterator_to_array(
3228                                                 $dbr->select(
3229                                                         'page_restrictions',
3230                                                         [ 'pr_type', 'pr_expiry', 'pr_level', 'pr_cascade' ],
3231                                                         [ 'pr_page' => $this->getArticleID() ],
3232                                                         __METHOD__
3233                                                 )
3234                                         );
3235                                 }
3236                         );
3237
3238                         $this->loadRestrictionsFromRows( $rows, $oldFashionedRestrictions );
3239                 } else {
3240                         $title_protection = $this->getTitleProtectionInternal();
3241
3242                         if ( $title_protection ) {
3243                                 $now = wfTimestampNow();
3244                                 $expiry = wfGetDB( DB_REPLICA )->decodeExpiry( $title_protection['expiry'] );
3245
3246                                 if ( !$expiry || $expiry > $now ) {
3247                                         // Apply the restrictions
3248                                         $this->mRestrictionsExpiry['create'] = $expiry;
3249                                         $this->mRestrictions['create'] =
3250                                                 explode( ',', trim( $title_protection['permission'] ) );
3251                                 } else { // Get rid of the old restrictions
3252                                         $this->mTitleProtection = false;
3253                                 }
3254                         } else {
3255                                 $this->mRestrictionsExpiry['create'] = 'infinity';
3256                         }
3257                         $this->mRestrictionsLoaded = true;
3258                 }
3259         }
3260
3261         /**
3262          * Flush the protection cache in this object and force reload from the database.
3263          * This is used when updating protection from WikiPage::doUpdateRestrictions().
3264          */
3265         public function flushRestrictions() {
3266                 $this->mRestrictionsLoaded = false;
3267                 $this->mTitleProtection = null;
3268         }
3269
3270         /**
3271          * Purge expired restrictions from the page_restrictions table
3272          *
3273          * This will purge no more than $wgUpdateRowsPerQuery page_restrictions rows
3274          */
3275         static function purgeExpiredRestrictions() {
3276                 if ( wfReadOnly() ) {
3277                         return;
3278                 }
3279
3280                 DeferredUpdates::addUpdate( new AtomicSectionUpdate(
3281                         wfGetDB( DB_MASTER ),
3282                         __METHOD__,
3283                         function ( IDatabase $dbw, $fname ) {
3284                                 $config = MediaWikiServices::getInstance()->getMainConfig();
3285                                 $ids = $dbw->selectFieldValues(
3286                                         'page_restrictions',
3287                                         'pr_id',
3288                                         [ 'pr_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ],
3289                                         $fname,
3290                                         [ 'LIMIT' => $config->get( 'UpdateRowsPerQuery' ) ] // T135470
3291                                 );
3292                                 if ( $ids ) {
3293                                         $dbw->delete( 'page_restrictions', [ 'pr_id' => $ids ], $fname );
3294                                 }
3295                         }
3296                 ) );
3297
3298                 DeferredUpdates::addUpdate( new AtomicSectionUpdate(
3299                         wfGetDB( DB_MASTER ),
3300                         __METHOD__,
3301                         function ( IDatabase $dbw, $fname ) {
3302                                 $dbw->delete(
3303                                         'protected_titles',
3304                                         [ 'pt_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ],
3305                                         $fname
3306                                 );
3307                         }
3308                 ) );
3309         }
3310
3311         /**
3312          * Does this have subpages?  (Warning, usually requires an extra DB query.)
3313          *
3314          * @return bool
3315          */
3316         public function hasSubpages() {
3317                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
3318                         # Duh
3319                         return false;
3320                 }
3321
3322                 # We dynamically add a member variable for the purpose of this method
3323                 # alone to cache the result.  There's no point in having it hanging
3324                 # around uninitialized in every Title object; therefore we only add it
3325                 # if needed and don't declare it statically.
3326                 if ( $this->mHasSubpages === null ) {
3327                         $this->mHasSubpages = false;
3328                         $subpages = $this->getSubpages( 1 );
3329                         if ( $subpages instanceof TitleArray ) {
3330                                 $this->mHasSubpages = (bool)$subpages->count();
3331                         }
3332                 }
3333
3334                 return $this->mHasSubpages;
3335         }
3336
3337         /**
3338          * Get all subpages of this page.
3339          *
3340          * @param int $limit Maximum number of subpages to fetch; -1 for no limit
3341          * @return TitleArray|array TitleArray, or empty array if this page's namespace
3342          *  doesn't allow subpages
3343          */
3344         public function getSubpages( $limit = -1 ) {
3345                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3346                         return [];
3347                 }
3348
3349                 $dbr = wfGetDB( DB_REPLICA );
3350                 $conds['page_namespace'] = $this->getNamespace();
3351                 $conds[] = 'page_title ' . $dbr->buildLike( $this->getDBkey() . '/', $dbr->anyString() );
3352                 $options = [];
3353                 if ( $limit > -1 ) {
3354                         $options['LIMIT'] = $limit;
3355                 }
3356                 return TitleArray::newFromResult(
3357                         $dbr->select( 'page',
3358                                 [ 'page_id', 'page_namespace', 'page_title', 'page_is_redirect' ],
3359                                 $conds,
3360                                 __METHOD__,
3361                                 $options
3362                         )
3363                 );
3364         }
3365
3366         /**
3367          * Is there a version of this page in the deletion archive?
3368          *
3369          * @return int The number of archived revisions
3370          */
3371         public function isDeleted() {
3372                 if ( $this->getNamespace() < 0 ) {
3373                         $n = 0;
3374                 } else {
3375                         $dbr = wfGetDB( DB_REPLICA );
3376
3377                         $n = $dbr->selectField( 'archive', 'COUNT(*)',
3378                                 [ 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ],
3379                                 __METHOD__
3380                         );
3381                         if ( $this->getNamespace() == NS_FILE ) {
3382                                 $n += $dbr->selectField( 'filearchive', 'COUNT(*)',
3383                                         [ 'fa_name' => $this->getDBkey() ],
3384                                         __METHOD__
3385                                 );
3386                         }
3387                 }
3388                 return (int)$n;
3389         }
3390
3391         /**
3392          * Is there a version of this page in the deletion archive?
3393          *
3394          * @return bool
3395          */
3396         public function isDeletedQuick() {
3397                 if ( $this->getNamespace() < 0 ) {
3398                         return false;
3399                 }
3400                 $dbr = wfGetDB( DB_REPLICA );
3401                 $deleted = (bool)$dbr->selectField( 'archive', '1',
3402                         [ 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ],
3403                         __METHOD__
3404                 );
3405                 if ( !$deleted && $this->getNamespace() == NS_FILE ) {
3406                         $deleted = (bool)$dbr->selectField( 'filearchive', '1',
3407                                 [ 'fa_name' => $this->getDBkey() ],
3408                                 __METHOD__
3409                         );
3410                 }
3411                 return $deleted;
3412         }
3413
3414         /**
3415          * Get the article ID for this Title from the link cache,
3416          * adding it if necessary
3417          *
3418          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select
3419          *  for update
3420          * @return int The ID
3421          */
3422         public function getArticleID( $flags = 0 ) {
3423                 if ( $this->getNamespace() < 0 ) {
3424                         $this->mArticleID = 0;
3425                         return $this->mArticleID;
3426                 }
3427                 $linkCache = LinkCache::singleton();
3428                 if ( $flags & self::GAID_FOR_UPDATE ) {
3429                         $oldUpdate = $linkCache->forUpdate( true );
3430                         $linkCache->clearLink( $this );
3431                         $this->mArticleID = $linkCache->addLinkObj( $this );
3432                         $linkCache->forUpdate( $oldUpdate );
3433                 } else {
3434                         if ( -1 == $this->mArticleID ) {
3435                                 $this->mArticleID = $linkCache->addLinkObj( $this );
3436                         }
3437                 }
3438                 return $this->mArticleID;
3439         }
3440
3441         /**
3442          * Is this an article that is a redirect page?
3443          * Uses link cache, adding it if necessary
3444          *
3445          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3446          * @return bool
3447          */
3448         public function isRedirect( $flags = 0 ) {
3449                 if ( !is_null( $this->mRedirect ) ) {
3450                         return $this->mRedirect;
3451                 }
3452                 if ( !$this->getArticleID( $flags ) ) {
3453                         $this->mRedirect = false;
3454                         return $this->mRedirect;
3455                 }
3456
3457                 $linkCache = LinkCache::singleton();
3458                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3459                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'redirect' );
3460                 if ( $cached === null ) {
3461                         # Trust LinkCache's state over our own
3462                         # LinkCache is telling us that the page doesn't exist, despite there being cached
3463                         # data relating to an existing page in $this->mArticleID. Updaters should clear
3464                         # LinkCache as appropriate, or use $flags = Title::GAID_FOR_UPDATE. If that flag is
3465                         # set, then LinkCache will definitely be up to date here, since getArticleID() forces
3466                         # LinkCache to refresh its data from the master.
3467                         $this->mRedirect = false;
3468                         return $this->mRedirect;
3469                 }
3470
3471                 $this->mRedirect = (bool)$cached;
3472
3473                 return $this->mRedirect;
3474         }
3475
3476         /**
3477          * What is the length of this page?
3478          * Uses link cache, adding it if necessary
3479          *
3480          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3481          * @return int
3482          */
3483         public function getLength( $flags = 0 ) {
3484                 if ( $this->mLength != -1 ) {
3485                         return $this->mLength;
3486                 }
3487                 if ( !$this->getArticleID( $flags ) ) {
3488                         $this->mLength = 0;
3489                         return $this->mLength;
3490                 }
3491                 $linkCache = LinkCache::singleton();
3492                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3493                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'length' );
3494                 if ( $cached === null ) {
3495                         # Trust LinkCache's state over our own, as for isRedirect()
3496                         $this->mLength = 0;
3497                         return $this->mLength;
3498                 }
3499
3500                 $this->mLength = intval( $cached );
3501
3502                 return $this->mLength;
3503         }
3504
3505         /**
3506          * What is the page_latest field for this page?
3507          *
3508          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3509          * @return int Int or 0 if the page doesn't exist
3510          */
3511         public function getLatestRevID( $flags = 0 ) {
3512                 if ( !( $flags & self::GAID_FOR_UPDATE ) && $this->mLatestID !== false ) {
3513                         return intval( $this->mLatestID );
3514                 }
3515                 if ( !$this->getArticleID( $flags ) ) {
3516                         $this->mLatestID = 0;
3517                         return $this->mLatestID;
3518                 }
3519                 $linkCache = LinkCache::singleton();
3520                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3521                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'revision' );
3522                 if ( $cached === null ) {
3523                         # Trust LinkCache's state over our own, as for isRedirect()
3524                         $this->mLatestID = 0;
3525                         return $this->mLatestID;
3526                 }
3527
3528                 $this->mLatestID = intval( $cached );
3529
3530                 return $this->mLatestID;
3531         }
3532
3533         /**
3534          * This clears some fields in this object, and clears any associated
3535          * keys in the "bad links" section of the link cache.
3536          *
3537          * - This is called from WikiPage::doEditContent() and WikiPage::insertOn() to allow
3538          * loading of the new page_id. It's also called from
3539          * WikiPage::doDeleteArticleReal()
3540          *
3541          * @param int $newid The new Article ID
3542          */
3543         public function resetArticleID( $newid ) {
3544                 $linkCache = LinkCache::singleton();
3545                 $linkCache->clearLink( $this );
3546
3547                 if ( $newid === false ) {
3548                         $this->mArticleID = -1;
3549                 } else {
3550                         $this->mArticleID = intval( $newid );
3551                 }
3552                 $this->mRestrictionsLoaded = false;
3553                 $this->mRestrictions = [];
3554                 $this->mOldRestrictions = false;
3555                 $this->mRedirect = null;
3556                 $this->mLength = -1;
3557                 $this->mLatestID = false;
3558                 $this->mContentModel = false;
3559                 $this->mEstimateRevisions = null;
3560                 $this->mPageLanguage = false;
3561                 $this->mDbPageLanguage = false;
3562                 $this->mIsBigDeletion = null;
3563         }
3564
3565         public static function clearCaches() {
3566                 $linkCache = LinkCache::singleton();
3567                 $linkCache->clear();
3568
3569                 $titleCache = self::getTitleCache();
3570                 $titleCache->clear();
3571         }
3572
3573         /**
3574          * Capitalize a text string for a title if it belongs to a namespace that capitalizes
3575          *
3576          * @param string $text Containing title to capitalize
3577          * @param int $ns Namespace index, defaults to NS_MAIN
3578          * @return string Containing capitalized title
3579          */
3580         public static function capitalize( $text, $ns = NS_MAIN ) {
3581                 global $wgContLang;
3582
3583                 if ( MWNamespace::isCapitalized( $ns ) ) {
3584                         return $wgContLang->ucfirst( $text );
3585                 } else {
3586                         return $text;
3587                 }
3588         }
3589
3590         /**
3591          * Secure and split - main initialisation function for this object
3592          *
3593          * Assumes that mDbkeyform has been set, and is urldecoded
3594          * and uses underscores, but not otherwise munged.  This function
3595          * removes illegal characters, splits off the interwiki and
3596          * namespace prefixes, sets the other forms, and canonicalizes
3597          * everything.
3598          *
3599          * @throws MalformedTitleException On invalid titles
3600          * @return bool True on success
3601          */
3602         private function secureAndSplit() {
3603                 # Initialisation
3604                 $this->mInterwiki = '';
3605                 $this->mFragment = '';
3606                 $this->mNamespace = $this->mDefaultNamespace; # Usually NS_MAIN
3607
3608                 $dbkey = $this->mDbkeyform;
3609
3610                 // @note: splitTitleString() is a temporary hack to allow MediaWikiTitleCodec to share
3611                 //        the parsing code with Title, while avoiding massive refactoring.
3612                 // @todo: get rid of secureAndSplit, refactor parsing code.
3613                 // @note: getTitleParser() returns a TitleParser implementation which does not have a
3614                 //        splitTitleString method, but the only implementation (MediaWikiTitleCodec) does
3615                 $titleCodec = MediaWikiServices::getInstance()->getTitleParser();
3616                 // MalformedTitleException can be thrown here
3617                 $parts = $titleCodec->splitTitleString( $dbkey, $this->getDefaultNamespace() );
3618
3619                 # Fill fields
3620                 $this->setFragment( '#' . $parts['fragment'] );
3621                 $this->mInterwiki = $parts['interwiki'];
3622                 $this->mLocalInterwiki = $parts['local_interwiki'];
3623                 $this->mNamespace = $parts['namespace'];
3624                 $this->mUserCaseDBKey = $parts['user_case_dbkey'];
3625
3626                 $this->mDbkeyform = $parts['dbkey'];
3627                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
3628                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
3629
3630                 # We already know that some pages won't be in the database!
3631                 if ( $this->isExternal() || $this->isSpecialPage() ) {
3632                         $this->mArticleID = 0;
3633                 }
3634
3635                 return true;
3636         }
3637
3638         /**
3639          * Get an array of Title objects linking to this Title
3640          * Also stores the IDs in the link cache.
3641          *
3642          * WARNING: do not use this function on arbitrary user-supplied titles!
3643          * On heavily-used templates it will max out the memory.
3644          *
3645          * @param array $options May be FOR UPDATE
3646          * @param string $table Table name
3647          * @param string $prefix Fields prefix
3648          * @return Title[] Array of Title objects linking here
3649          */
3650         public function getLinksTo( $options = [], $table = 'pagelinks', $prefix = 'pl' ) {
3651                 if ( count( $options ) > 0 ) {
3652                         $db = wfGetDB( DB_MASTER );
3653                 } else {
3654                         $db = wfGetDB( DB_REPLICA );
3655                 }
3656
3657                 $res = $db->select(
3658                         [ 'page', $table ],
3659                         self::getSelectFields(),
3660                         [
3661                                 "{$prefix}_from=page_id",
3662                                 "{$prefix}_namespace" => $this->getNamespace(),
3663                                 "{$prefix}_title" => $this->getDBkey() ],
3664                         __METHOD__,
3665                         $options
3666                 );
3667
3668                 $retVal = [];
3669                 if ( $res->numRows() ) {
3670                         $linkCache = LinkCache::singleton();
3671                         foreach ( $res as $row ) {
3672                                 $titleObj = self::makeTitle( $row->page_namespace, $row->page_title );
3673                                 if ( $titleObj ) {
3674                                         $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3675                                         $retVal[] = $titleObj;
3676                                 }
3677                         }
3678                 }
3679                 return $retVal;
3680         }
3681
3682         /**
3683          * Get an array of Title objects using this Title as a template
3684          * Also stores the IDs in the link cache.
3685          *
3686          * WARNING: do not use this function on arbitrary user-supplied titles!
3687          * On heavily-used templates it will max out the memory.
3688          *
3689          * @param array $options Query option to Database::select()
3690          * @return Title[] Array of Title the Title objects linking here
3691          */
3692         public function getTemplateLinksTo( $options = [] ) {
3693                 return $this->getLinksTo( $options, 'templatelinks', 'tl' );
3694         }
3695
3696         /**
3697          * Get an array of Title objects linked from this Title
3698          * Also stores the IDs in the link cache.
3699          *
3700          * WARNING: do not use this function on arbitrary user-supplied titles!
3701          * On heavily-used templates it will max out the memory.
3702          *
3703          * @param array $options Query option to Database::select()
3704          * @param string $table Table name
3705          * @param string $prefix Fields prefix
3706          * @return array Array of Title objects linking here
3707          */
3708         public function getLinksFrom( $options = [], $table = 'pagelinks', $prefix = 'pl' ) {
3709                 $id = $this->getArticleID();
3710
3711                 # If the page doesn't exist; there can't be any link from this page
3712                 if ( !$id ) {
3713                         return [];
3714                 }
3715
3716                 $db = wfGetDB( DB_REPLICA );
3717
3718                 $blNamespace = "{$prefix}_namespace";
3719                 $blTitle = "{$prefix}_title";
3720
3721                 $pageQuery = WikiPage::getQueryInfo();
3722                 $res = $db->select(
3723                         [ $table, 'nestpage' => $pageQuery['tables'] ],
3724                         array_merge(
3725                                 [ $blNamespace, $blTitle ],
3726                                 $pageQuery['fields']
3727                         ),
3728                         [ "{$prefix}_from" => $id ],
3729                         __METHOD__,
3730                         $options,
3731                         [ 'nestpage' => [
3732                                 'LEFT JOIN',
3733                                 [ "page_namespace=$blNamespace", "page_title=$blTitle" ]
3734                         ] ] + $pageQuery['joins']
3735                 );
3736
3737                 $retVal = [];
3738                 $linkCache = LinkCache::singleton();
3739                 foreach ( $res as $row ) {
3740                         if ( $row->page_id ) {
3741                                 $titleObj = self::newFromRow( $row );
3742                         } else {
3743                                 $titleObj = self::makeTitle( $row->$blNamespace, $row->$blTitle );
3744                                 $linkCache->addBadLinkObj( $titleObj );
3745                         }
3746                         $retVal[] = $titleObj;
3747                 }
3748
3749                 return $retVal;
3750         }
3751
3752         /**
3753          * Get an array of Title objects used on this Title as a template
3754          * Also stores the IDs in the link cache.
3755          *
3756          * WARNING: do not use this function on arbitrary user-supplied titles!
3757          * On heavily-used templates it will max out the memory.
3758          *
3759          * @param array $options May be FOR UPDATE
3760          * @return Title[] Array of Title the Title objects used here
3761          */
3762         public function getTemplateLinksFrom( $options = [] ) {
3763                 return $this->getLinksFrom( $options, 'templatelinks', 'tl' );
3764         }
3765
3766         /**
3767          * Get an array of Title objects referring to non-existent articles linked
3768          * from this page.
3769          *
3770          * @todo check if needed (used only in SpecialBrokenRedirects.php, and
3771          *   should use redirect table in this case).
3772          * @return Title[] Array of Title the Title objects
3773          */
3774         public function getBrokenLinksFrom() {
3775                 if ( $this->getArticleID() == 0 ) {
3776                         # All links from article ID 0 are false positives
3777                         return [];
3778                 }
3779
3780                 $dbr = wfGetDB( DB_REPLICA );
3781                 $res = $dbr->select(
3782                         [ 'page', 'pagelinks' ],
3783                         [ 'pl_namespace', 'pl_title' ],
3784                         [
3785                                 'pl_from' => $this->getArticleID(),
3786                                 'page_namespace IS NULL'
3787                         ],
3788                         __METHOD__, [],
3789                         [
3790                                 'page' => [
3791                                         'LEFT JOIN',
3792                                         [ 'pl_namespace=page_namespace', 'pl_title=page_title' ]
3793                                 ]
3794                         ]
3795                 );
3796
3797                 $retVal = [];
3798                 foreach ( $res as $row ) {
3799                         $retVal[] = self::makeTitle( $row->pl_namespace, $row->pl_title );
3800                 }
3801                 return $retVal;
3802         }
3803
3804         /**
3805          * Get a list of URLs to purge from the CDN cache when this
3806          * page changes
3807          *
3808          * @return string[] Array of String the URLs
3809          */
3810         public function getCdnUrls() {
3811                 $urls = [
3812                         $this->getInternalURL(),
3813                         $this->getInternalURL( 'action=history' )
3814                 ];
3815
3816                 $pageLang = $this->getPageLanguage();
3817                 if ( $pageLang->hasVariants() ) {
3818                         $variants = $pageLang->getVariants();
3819                         foreach ( $variants as $vCode ) {
3820                                 $urls[] = $this->getInternalURL( $vCode );
3821                         }
3822                 }
3823
3824                 // If we are looking at a css/js user subpage, purge the action=raw.
3825                 if ( $this->isUserJsConfigPage() ) {
3826                         $urls[] = $this->getInternalURL( 'action=raw&ctype=text/javascript' );
3827                 } elseif ( $this->isUserCssConfigPage() ) {
3828                         $urls[] = $this->getInternalURL( 'action=raw&ctype=text/css' );
3829                 }
3830
3831                 Hooks::run( 'TitleSquidURLs', [ $this, &$urls ] );
3832                 return $urls;
3833         }
3834
3835         /**
3836          * @deprecated since 1.27 use getCdnUrls()
3837          */
3838         public function getSquidURLs() {
3839                 return $this->getCdnUrls();
3840         }
3841
3842         /**
3843          * Purge all applicable CDN URLs
3844          */
3845         public function purgeSquid() {
3846                 DeferredUpdates::addUpdate(
3847                         new CdnCacheUpdate( $this->getCdnUrls() ),
3848                         DeferredUpdates::PRESEND
3849                 );
3850         }
3851
3852         /**
3853          * Check whether a given move operation would be valid.
3854          * Returns true if ok, or a getUserPermissionsErrors()-like array otherwise
3855          *
3856          * @deprecated since 1.25, use MovePage's methods instead
3857          * @param Title &$nt The new title
3858          * @param bool $auth Whether to check user permissions (uses $wgUser)
3859          * @param string $reason Is the log summary of the move, used for spam checking
3860          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3861          */
3862         public function isValidMoveOperation( &$nt, $auth = true, $reason = '' ) {
3863                 global $wgUser;
3864
3865                 if ( !( $nt instanceof Title ) ) {
3866                         // Normally we'd add this to $errors, but we'll get
3867                         // lots of syntax errors if $nt is not an object
3868                         return [ [ 'badtitletext' ] ];
3869                 }
3870
3871                 $mp = new MovePage( $this, $nt );
3872                 $errors = $mp->isValidMove()->getErrorsArray();
3873                 if ( $auth ) {
3874                         $errors = wfMergeErrorArrays(
3875                                 $errors,
3876                                 $mp->checkPermissions( $wgUser, $reason )->getErrorsArray()
3877                         );
3878                 }
3879
3880                 return $errors ?: true;
3881         }
3882
3883         /**
3884          * Check if the requested move target is a valid file move target
3885          * @todo move this to MovePage
3886          * @param Title $nt Target title
3887          * @return array List of errors
3888          */
3889         protected function validateFileMoveOperation( $nt ) {
3890                 global $wgUser;
3891
3892                 $errors = [];
3893
3894                 $destFile = wfLocalFile( $nt );
3895                 $destFile->load( File::READ_LATEST );
3896                 if ( !$wgUser->isAllowed( 'reupload-shared' )
3897                         && !$destFile->exists() && wfFindFile( $nt )
3898                 ) {
3899                         $errors[] = [ 'file-exists-sharedrepo' ];
3900                 }
3901
3902                 return $errors;
3903         }
3904
3905         /**
3906          * Move a title to a new location
3907          *
3908          * @deprecated since 1.25, use the MovePage class instead
3909          * @param Title &$nt The new title
3910          * @param bool $auth Indicates whether $wgUser's permissions
3911          *  should be checked
3912          * @param string $reason The reason for the move
3913          * @param bool $createRedirect Whether to create a redirect from the old title to the new title.
3914          *  Ignored if the user doesn't have the suppressredirect right.
3915          * @param array $changeTags Applied to the entry in the move log and redirect page revision
3916          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3917          */
3918         public function moveTo( &$nt, $auth = true, $reason = '', $createRedirect = true,
3919                 array $changeTags = []
3920         ) {
3921                 global $wgUser;
3922                 $err = $this->isValidMoveOperation( $nt, $auth, $reason );
3923                 if ( is_array( $err ) ) {
3924                         // Auto-block user's IP if the account was "hard" blocked
3925                         $wgUser->spreadAnyEditBlock();
3926                         return $err;
3927                 }
3928                 // Check suppressredirect permission
3929                 if ( $auth && !$wgUser->isAllowed( 'suppressredirect' ) ) {
3930                         $createRedirect = true;
3931                 }
3932
3933                 $mp = new MovePage( $this, $nt );
3934                 $status = $mp->move( $wgUser, $reason, $createRedirect, $changeTags );
3935                 if ( $status->isOK() ) {
3936                         return true;
3937                 } else {
3938                         return $status->getErrorsArray();
3939                 }
3940         }
3941
3942         /**
3943          * Move this page's subpages to be subpages of $nt
3944          *
3945          * @param Title $nt Move target
3946          * @param bool $auth Whether $wgUser's permissions should be checked
3947          * @param string $reason The reason for the move
3948          * @param bool $createRedirect Whether to create redirects from the old subpages to
3949          *     the new ones Ignored if the user doesn't have the 'suppressredirect' right
3950          * @param array $changeTags Applied to the entry in the move log and redirect page revision
3951          * @return array Array with old page titles as keys, and strings (new page titles) or
3952          *     getUserPermissionsErrors()-like arrays (errors) as values, or a
3953          *     getUserPermissionsErrors()-like error array with numeric indices if
3954          *     no pages were moved
3955          */
3956         public function moveSubpages( $nt, $auth = true, $reason = '', $createRedirect = true,
3957                 array $changeTags = []
3958         ) {
3959                 global $wgMaximumMovedPages;
3960                 // Check permissions
3961                 if ( !$this->userCan( 'move-subpages' ) ) {
3962                         return [
3963                                 [ 'cant-move-subpages' ],
3964                         ];
3965                 }
3966                 // Do the source and target namespaces support subpages?
3967                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3968                         return [
3969                                 [ 'namespace-nosubpages', MWNamespace::getCanonicalName( $this->getNamespace() ) ],
3970                         ];
3971                 }
3972                 if ( !MWNamespace::hasSubpages( $nt->getNamespace() ) ) {
3973                         return [
3974                                 [ 'namespace-nosubpages', MWNamespace::getCanonicalName( $nt->getNamespace() ) ],
3975                         ];
3976                 }
3977
3978                 $subpages = $this->getSubpages( $wgMaximumMovedPages + 1 );
3979                 $retval = [];
3980                 $count = 0;
3981                 foreach ( $subpages as $oldSubpage ) {
3982                         $count++;
3983                         if ( $count > $wgMaximumMovedPages ) {
3984                                 $retval[$oldSubpage->getPrefixedText()] = [
3985                                         [ 'movepage-max-pages', $wgMaximumMovedPages ],
3986                                 ];
3987                                 break;
3988                         }
3989
3990                         // We don't know whether this function was called before
3991                         // or after moving the root page, so check both
3992                         // $this and $nt
3993                         if ( $oldSubpage->getArticleID() == $this->getArticleID()
3994                                 || $oldSubpage->getArticleID() == $nt->getArticleID()
3995                         ) {
3996                                 // When moving a page to a subpage of itself,
3997                                 // don't move it twice
3998                                 continue;
3999                         }
4000                         $newPageName = preg_replace(
4001                                         '#^' . preg_quote( $this->getDBkey(), '#' ) . '#',
4002                                         StringUtils::escapeRegexReplacement( $nt->getDBkey() ), # T23234
4003                                         $oldSubpage->getDBkey() );
4004                         if ( $oldSubpage->isTalkPage() ) {
4005                                 $newNs = $nt->getTalkPage()->getNamespace();
4006                         } else {
4007                                 $newNs = $nt->getSubjectPage()->getNamespace();
4008                         }
4009                         # T16385: we need makeTitleSafe because the new page names may
4010                         # be longer than 255 characters.
4011                         $newSubpage = self::makeTitleSafe( $newNs, $newPageName );
4012
4013                         $success = $oldSubpage->moveTo( $newSubpage, $auth, $reason, $createRedirect, $changeTags );
4014                         if ( $success === true ) {
4015                                 $retval[$oldSubpage->getPrefixedText()] = $newSubpage->getPrefixedText();
4016                         } else {
4017                                 $retval[$oldSubpage->getPrefixedText()] = $success;
4018                         }
4019                 }
4020                 return $retval;
4021         }
4022
4023         /**
4024          * Checks if this page is just a one-rev redirect.
4025          * Adds lock, so don't use just for light purposes.
4026          *
4027          * @return bool
4028          */
4029         public function isSingleRevRedirect() {
4030                 global $wgContentHandlerUseDB;
4031
4032                 $dbw = wfGetDB( DB_MASTER );
4033
4034                 # Is it a redirect?
4035                 $fields = [ 'page_is_redirect', 'page_latest', 'page_id' ];
4036                 if ( $wgContentHandlerUseDB ) {
4037                         $fields[] = 'page_content_model';
4038                 }
4039
4040                 $row = $dbw->selectRow( 'page',
4041                         $fields,
4042                         $this->pageCond(),
4043                         __METHOD__,
4044                         [ 'FOR UPDATE' ]
4045                 );
4046                 # Cache some fields we may want
4047                 $this->mArticleID = $row ? intval( $row->page_id ) : 0;
4048                 $this->mRedirect = $row ? (bool)$row->page_is_redirect : false;
4049                 $this->mLatestID = $row ? intval( $row->page_latest ) : false;
4050                 $this->mContentModel = $row && isset( $row->page_content_model )
4051                         ? strval( $row->page_content_model )
4052                         : false;
4053
4054                 if ( !$this->mRedirect ) {
4055                         return false;
4056                 }
4057                 # Does the article have a history?
4058                 $row = $dbw->selectField( [ 'page', 'revision' ],
4059                         'rev_id',
4060                         [ 'page_namespace' => $this->getNamespace(),
4061                                 'page_title' => $this->getDBkey(),
4062                                 'page_id=rev_page',
4063                                 'page_latest != rev_id'
4064                         ],
4065                         __METHOD__,
4066                         [ 'FOR UPDATE' ]
4067                 );
4068                 # Return true if there was no history
4069                 return ( $row === false );
4070         }
4071
4072         /**
4073          * Checks if $this can be moved to a given Title
4074          * - Selects for update, so don't call it unless you mean business
4075          *
4076          * @deprecated since 1.25, use MovePage's methods instead
4077          * @param Title $nt The new title to check
4078          * @return bool
4079          */
4080         public function isValidMoveTarget( $nt ) {
4081                 # Is it an existing file?
4082                 if ( $nt->getNamespace() == NS_FILE ) {
4083                         $file = wfLocalFile( $nt );
4084                         $file->load( File::READ_LATEST );
4085                         if ( $file->exists() ) {
4086                                 wfDebug( __METHOD__ . ": file exists\n" );
4087                                 return false;
4088                         }
4089                 }
4090                 # Is it a redirect with no history?
4091                 if ( !$nt->isSingleRevRedirect() ) {
4092                         wfDebug( __METHOD__ . ": not a one-rev redirect\n" );
4093                         return false;
4094                 }
4095                 # Get the article text
4096                 $rev = Revision::newFromTitle( $nt, false, Revision::READ_LATEST );
4097                 if ( !is_object( $rev ) ) {
4098                         return false;
4099                 }
4100                 $content = $rev->getContent();
4101                 # Does the redirect point to the source?
4102                 # Or is it a broken self-redirect, usually caused by namespace collisions?
4103                 $redirTitle = $content ? $content->getRedirectTarget() : null;
4104
4105                 if ( $redirTitle ) {
4106                         if ( $redirTitle->getPrefixedDBkey() != $this->getPrefixedDBkey() &&
4107                                 $redirTitle->getPrefixedDBkey() != $nt->getPrefixedDBkey() ) {
4108                                 wfDebug( __METHOD__ . ": redirect points to other page\n" );
4109                                 return false;
4110                         } else {
4111                                 return true;
4112                         }
4113                 } else {
4114                         # Fail safe (not a redirect after all. strange.)
4115                         wfDebug( __METHOD__ . ": failsafe: database sais " . $nt->getPrefixedDBkey() .
4116                                                 " is a redirect, but it doesn't contain a valid redirect.\n" );
4117                         return false;
4118                 }
4119         }
4120
4121         /**
4122          * Get categories to which this Title belongs and return an array of
4123          * categories' names.
4124          *
4125          * @return array Array of parents in the form:
4126          *     $parent => $currentarticle
4127          */
4128         public function getParentCategories() {
4129                 global $wgContLang;
4130
4131                 $data = [];
4132
4133                 $titleKey = $this->getArticleID();
4134
4135                 if ( $titleKey === 0 ) {
4136                         return $data;
4137                 }
4138
4139                 $dbr = wfGetDB( DB_REPLICA );
4140
4141                 $res = $dbr->select(
4142                         'categorylinks',
4143                         'cl_to',
4144                         [ 'cl_from' => $titleKey ],
4145                         __METHOD__
4146                 );
4147
4148                 if ( $res->numRows() > 0 ) {
4149                         foreach ( $res as $row ) {
4150                                 // $data[] = Title::newFromText($wgContLang->getNsText ( NS_CATEGORY ).':'.$row->cl_to);
4151                                 $data[$wgContLang->getNsText( NS_CATEGORY ) . ':' . $row->cl_to] = $this->getFullText();
4152                         }
4153                 }
4154                 return $data;
4155         }
4156
4157         /**
4158          * Get a tree of parent categories
4159          *
4160          * @param array $children Array with the children in the keys, to check for circular refs
4161          * @return array Tree of parent categories
4162          */
4163         public function getParentCategoryTree( $children = [] ) {
4164                 $stack = [];
4165                 $parents = $this->getParentCategories();
4166
4167                 if ( $parents ) {
4168                         foreach ( $parents as $parent => $current ) {
4169                                 if ( array_key_exists( $parent, $children ) ) {
4170                                         # Circular reference
4171                                         $stack[$parent] = [];
4172                                 } else {
4173                                         $nt = self::newFromText( $parent );
4174                                         if ( $nt ) {
4175                                                 $stack[$parent] = $nt->getParentCategoryTree( $children + [ $parent => 1 ] );
4176                                         }
4177                                 }
4178                         }
4179                 }
4180
4181                 return $stack;
4182         }
4183
4184         /**
4185          * Get an associative array for selecting this title from
4186          * the "page" table
4187          *
4188          * @return array Array suitable for the $where parameter of DB::select()
4189          */
4190         public function pageCond() {
4191                 if ( $this->mArticleID > 0 ) {
4192                         // PK avoids secondary lookups in InnoDB, shouldn't hurt other DBs
4193                         return [ 'page_id' => $this->mArticleID ];
4194                 } else {
4195                         return [ 'page_namespace' => $this->mNamespace, 'page_title' => $this->mDbkeyform ];
4196                 }
4197         }
4198
4199         /**
4200          * Get next/previous revision ID relative to another revision ID
4201          * @param int $revId Revision ID. Get the revision that was before this one.
4202          * @param int $flags Title::GAID_FOR_UPDATE
4203          * @param string $dir 'next' or 'prev'
4204          * @return int|bool New revision ID, or false if none exists
4205          */
4206         private function getRelativeRevisionID( $revId, $flags, $dir ) {
4207                 $revId = (int)$revId;
4208                 if ( $dir === 'next' ) {
4209                         $op = '>';
4210                         $sort = 'ASC';
4211                 } elseif ( $dir === 'prev' ) {
4212                         $op = '<';
4213                         $sort = 'DESC';
4214                 } else {
4215                         throw new InvalidArgumentException( '$dir must be "next" or "prev"' );
4216                 }
4217
4218                 if ( $flags & self::GAID_FOR_UPDATE ) {
4219                         $db = wfGetDB( DB_MASTER );
4220                 } else {
4221                         $db = wfGetDB( DB_REPLICA, 'contributions' );
4222                 }
4223
4224                 // Intentionally not caring if the specified revision belongs to this
4225                 // page. We only care about the timestamp.
4226                 $ts = $db->selectField( 'revision', 'rev_timestamp', [ 'rev_id' => $revId ], __METHOD__ );
4227                 if ( $ts === false ) {
4228                         $ts = $db->selectField( 'archive', 'ar_timestamp', [ 'ar_rev_id' => $revId ], __METHOD__ );
4229                         if ( $ts === false ) {
4230                                 // Or should this throw an InvalidArgumentException or something?
4231                                 return false;
4232                         }
4233                 }
4234                 $ts = $db->addQuotes( $ts );
4235
4236                 $revId = $db->selectField( 'revision', 'rev_id',
4237                         [
4238                                 'rev_page' => $this->getArticleID( $flags ),
4239                                 "rev_timestamp $op $ts OR (rev_timestamp = $ts AND rev_id $op $revId)"
4240                         ],
4241                         __METHOD__,
4242                         [
4243                                 'ORDER BY' => "rev_timestamp $sort, rev_id $sort",
4244                                 'IGNORE INDEX' => 'rev_timestamp', // Probably needed for T159319
4245                         ]
4246                 );
4247
4248                 if ( $revId === false ) {
4249                         return false;
4250                 } else {
4251                         return intval( $revId );
4252                 }
4253         }
4254
4255         /**
4256          * Get the revision ID of the previous revision
4257          *
4258          * @param int $revId Revision ID. Get the revision that was before this one.
4259          * @param int $flags Title::GAID_FOR_UPDATE
4260          * @return int|bool Old revision ID, or false if none exists
4261          */
4262         public function getPreviousRevisionID( $revId, $flags = 0 ) {
4263                 return $this->getRelativeRevisionID( $revId, $flags, 'prev' );
4264         }
4265
4266         /**
4267          * Get the revision ID of the next revision
4268          *
4269          * @param int $revId Revision ID. Get the revision that was after this one.
4270          * @param int $flags Title::GAID_FOR_UPDATE
4271          * @return int|bool Next revision ID, or false if none exists
4272          */
4273         public function getNextRevisionID( $revId, $flags = 0 ) {
4274                 return $this->getRelativeRevisionID( $revId, $flags, 'next' );
4275         }
4276
4277         /**
4278          * Get the first revision of the page
4279          *
4280          * @param int $flags Title::GAID_FOR_UPDATE
4281          * @return Revision|null If page doesn't exist
4282          */
4283         public function getFirstRevision( $flags = 0 ) {
4284                 $pageId = $this->getArticleID( $flags );
4285                 if ( $pageId ) {
4286                         $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_REPLICA );
4287                         $revQuery = Revision::getQueryInfo();
4288                         $row = $db->selectRow( $revQuery['tables'], $revQuery['fields'],
4289                                 [ 'rev_page' => $pageId ],
4290                                 __METHOD__,
4291                                 [
4292                                         'ORDER BY' => 'rev_timestamp ASC, rev_id ASC',
4293                                         'IGNORE INDEX' => [ 'revision' => 'rev_timestamp' ], // See T159319
4294                                 ],
4295                                 $revQuery['joins']
4296                         );
4297                         if ( $row ) {
4298                                 return new Revision( $row );
4299                         }
4300                 }
4301                 return null;
4302         }
4303
4304         /**
4305          * Get the oldest revision timestamp of this page
4306          *
4307          * @param int $flags Title::GAID_FOR_UPDATE
4308          * @return string MW timestamp
4309          */
4310         public function getEarliestRevTime( $flags = 0 ) {
4311                 $rev = $this->getFirstRevision( $flags );
4312                 return $rev ? $rev->getTimestamp() : null;
4313         }
4314
4315         /**
4316          * Check if this is a new page
4317          *
4318          * @return bool
4319          */
4320         public function isNewPage() {
4321                 $dbr = wfGetDB( DB_REPLICA );
4322                 return (bool)$dbr->selectField( 'page', 'page_is_new', $this->pageCond(), __METHOD__ );
4323         }
4324
4325         /**
4326          * Check whether the number of revisions of this page surpasses $wgDeleteRevisionsLimit
4327          *
4328          * @return bool
4329          */
4330         public function isBigDeletion() {
4331                 global $wgDeleteRevisionsLimit;
4332
4333                 if ( !$wgDeleteRevisionsLimit ) {
4334                         return false;
4335                 }
4336
4337                 if ( $this->mIsBigDeletion === null ) {
4338                         $dbr = wfGetDB( DB_REPLICA );
4339
4340                         $revCount = $dbr->selectRowCount(
4341                                 'revision',
4342                                 '1',
4343                                 [ 'rev_page' => $this->getArticleID() ],
4344                                 __METHOD__,
4345                                 [ 'LIMIT' => $wgDeleteRevisionsLimit + 1 ]
4346                         );
4347
4348                         $this->mIsBigDeletion = $revCount > $wgDeleteRevisionsLimit;
4349                 }
4350
4351                 return $this->mIsBigDeletion;
4352         }
4353
4354         /**
4355          * Get the approximate revision count of this page.
4356          *
4357          * @return int
4358          */
4359         public function estimateRevisionCount() {
4360                 if ( !$this->exists() ) {
4361                         return 0;
4362                 }
4363
4364                 if ( $this->mEstimateRevisions === null ) {
4365                         $dbr = wfGetDB( DB_REPLICA );
4366                         $this->mEstimateRevisions = $dbr->estimateRowCount( 'revision', '*',
4367                                 [ 'rev_page' => $this->getArticleID() ], __METHOD__ );
4368                 }
4369
4370                 return $this->mEstimateRevisions;
4371         }
4372
4373         /**
4374          * Get the number of revisions between the given revision.
4375          * Used for diffs and other things that really need it.
4376          *
4377          * @param int|Revision $old Old revision or rev ID (first before range)
4378          * @param int|Revision $new New revision or rev ID (first after range)
4379          * @param int|null $max Limit of Revisions to count, will be incremented to detect truncations
4380          * @return int Number of revisions between these revisions.
4381          */
4382         public function countRevisionsBetween( $old, $new, $max = null ) {
4383                 if ( !( $old instanceof Revision ) ) {
4384                         $old = Revision::newFromTitle( $this, (int)$old );
4385                 }
4386                 if ( !( $new instanceof Revision ) ) {
4387                         $new = Revision::newFromTitle( $this, (int)$new );
4388                 }
4389                 if ( !$old || !$new ) {
4390                         return 0; // nothing to compare
4391                 }
4392                 $dbr = wfGetDB( DB_REPLICA );
4393                 $conds = [
4394                         'rev_page' => $this->getArticleID(),
4395                         'rev_timestamp > ' . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4396                         'rev_timestamp < ' . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4397                 ];
4398                 if ( $max !== null ) {
4399                         return $dbr->selectRowCount( 'revision', '1',
4400                                 $conds,
4401                                 __METHOD__,
4402                                 [ 'LIMIT' => $max + 1 ] // extra to detect truncation
4403                         );
4404                 } else {
4405                         return (int)$dbr->selectField( 'revision', 'count(*)', $conds, __METHOD__ );
4406                 }
4407         }
4408
4409         /**
4410          * Get the authors between the given revisions or revision IDs.
4411          * Used for diffs and other things that really need it.
4412          *
4413          * @since 1.23
4414          *
4415          * @param int|Revision $old Old revision or rev ID (first before range by default)
4416          * @param int|Revision $new New revision or rev ID (first after range by default)
4417          * @param int $limit Maximum number of authors
4418          * @param string|array $options (Optional): Single option, or an array of options:
4419          *     'include_old' Include $old in the range; $new is excluded.
4420          *     'include_new' Include $new in the range; $old is excluded.
4421          *     'include_both' Include both $old and $new in the range.
4422          *     Unknown option values are ignored.
4423          * @return array|null Names of revision authors in the range; null if not both revisions exist
4424          */
4425         public function getAuthorsBetween( $old, $new, $limit, $options = [] ) {
4426                 if ( !( $old instanceof Revision ) ) {
4427                         $old = Revision::newFromTitle( $this, (int)$old );
4428                 }
4429                 if ( !( $new instanceof Revision ) ) {
4430                         $new = Revision::newFromTitle( $this, (int)$new );
4431                 }
4432                 // XXX: what if Revision objects are passed in, but they don't refer to this title?
4433                 // Add $old->getPage() != $new->getPage() || $old->getPage() != $this->getArticleID()
4434                 // in the sanity check below?
4435                 if ( !$old || !$new ) {
4436                         return null; // nothing to compare
4437                 }
4438                 $authors = [];
4439                 $old_cmp = '>';
4440                 $new_cmp = '<';
4441                 $options = (array)$options;
4442                 if ( in_array( 'include_old', $options ) ) {
4443                         $old_cmp = '>=';
4444                 }
4445                 if ( in_array( 'include_new', $options ) ) {
4446                         $new_cmp = '<=';
4447                 }
4448                 if ( in_array( 'include_both', $options ) ) {
4449                         $old_cmp = '>=';
4450                         $new_cmp = '<=';
4451                 }
4452                 // No DB query needed if $old and $new are the same or successive revisions:
4453                 if ( $old->getId() === $new->getId() ) {
4454                         return ( $old_cmp === '>' && $new_cmp === '<' ) ?
4455                                 [] :
4456                                 [ $old->getUserText( Revision::RAW ) ];
4457                 } elseif ( $old->getId() === $new->getParentId() ) {
4458                         if ( $old_cmp === '>=' && $new_cmp === '<=' ) {
4459                                 $authors[] = $old->getUserText( Revision::RAW );
4460                                 if ( $old->getUserText( Revision::RAW ) != $new->getUserText( Revision::RAW ) ) {
4461                                         $authors[] = $new->getUserText( Revision::RAW );
4462                                 }
4463                         } elseif ( $old_cmp === '>=' ) {
4464                                 $authors[] = $old->getUserText( Revision::RAW );
4465                         } elseif ( $new_cmp === '<=' ) {
4466                                 $authors[] = $new->getUserText( Revision::RAW );
4467                         }
4468                         return $authors;
4469                 }
4470                 $dbr = wfGetDB( DB_REPLICA );
4471                 $res = $dbr->select( 'revision', 'DISTINCT rev_user_text',
4472                         [
4473                                 'rev_page' => $this->getArticleID(),
4474                                 "rev_timestamp $old_cmp " . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4475                                 "rev_timestamp $new_cmp " . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4476                         ], __METHOD__,
4477                         [ 'LIMIT' => $limit + 1 ] // add one so caller knows it was truncated
4478                 );
4479                 foreach ( $res as $row ) {
4480                         $authors[] = $row->rev_user_text;
4481                 }
4482                 return $authors;
4483         }
4484
4485         /**
4486          * Get the number of authors between the given revisions or revision IDs.
4487          * Used for diffs and other things that really need it.
4488          *
4489          * @param int|Revision $old Old revision or rev ID (first before range by default)
4490          * @param int|Revision $new New revision or rev ID (first after range by default)
4491          * @param int $limit Maximum number of authors
4492          * @param string|array $options (Optional): Single option, or an array of options:
4493          *     'include_old' Include $old in the range; $new is excluded.
4494          *     'include_new' Include $new in the range; $old is excluded.
4495          *     'include_both' Include both $old and $new in the range.
4496          *     Unknown option values are ignored.
4497          * @return int Number of revision authors in the range; zero if not both revisions exist
4498          */
4499         public function countAuthorsBetween( $old, $new, $limit, $options = [] ) {
4500                 $authors = $this->getAuthorsBetween( $old, $new, $limit, $options );
4501                 return $authors ? count( $authors ) : 0;
4502         }
4503
4504         /**
4505          * Compare with another title.
4506          *
4507          * @param Title $title
4508          * @return bool
4509          */
4510         public function equals( Title $title ) {
4511                 // Note: === is necessary for proper matching of number-like titles.
4512                 return $this->getInterwiki() === $title->getInterwiki()
4513                         && $this->getNamespace() == $title->getNamespace()
4514                         && $this->getDBkey() === $title->getDBkey();
4515         }
4516
4517         /**
4518          * Check if this title is a subpage of another title
4519          *
4520          * @param Title $title
4521          * @return bool
4522          */
4523         public function isSubpageOf( Title $title ) {
4524                 return $this->getInterwiki() === $title->getInterwiki()
4525                         && $this->getNamespace() == $title->getNamespace()
4526                         && strpos( $this->getDBkey(), $title->getDBkey() . '/' ) === 0;
4527         }
4528
4529         /**
4530          * Check if page exists.  For historical reasons, this function simply
4531          * checks for the existence of the title in the page table, and will
4532          * thus return false for interwiki links, special pages and the like.
4533          * If you want to know if a title can be meaningfully viewed, you should
4534          * probably call the isKnown() method instead.
4535          *
4536          * @param int $flags An optional bit field; may be Title::GAID_FOR_UPDATE to check
4537          *   from master/for update
4538          * @return bool
4539          */
4540         public function exists( $flags = 0 ) {
4541                 $exists = $this->getArticleID( $flags ) != 0;
4542                 Hooks::run( 'TitleExists', [ $this, &$exists ] );
4543                 return $exists;
4544         }
4545
4546         /**
4547          * Should links to this title be shown as potentially viewable (i.e. as
4548          * "bluelinks"), even if there's no record by this title in the page
4549          * table?
4550          *
4551          * This function is semi-deprecated for public use, as well as somewhat
4552          * misleadingly named.  You probably just want to call isKnown(), which
4553          * calls this function internally.
4554          *
4555          * (ISSUE: Most of these checks are cheap, but the file existence check
4556          * can potentially be quite expensive.  Including it here fixes a lot of
4557          * existing code, but we might want to add an optional parameter to skip
4558          * it and any other expensive checks.)
4559          *
4560          * @return bool
4561          */
4562         public function isAlwaysKnown() {
4563                 $isKnown = null;
4564
4565                 /**
4566                  * Allows overriding default behavior for determining if a page exists.
4567                  * If $isKnown is kept as null, regular checks happen. If it's
4568                  * a boolean, this value is returned by the isKnown method.
4569                  *
4570                  * @since 1.20
4571                  *
4572                  * @param Title $title
4573                  * @param bool|null $isKnown
4574                  */
4575                 Hooks::run( 'TitleIsAlwaysKnown', [ $this, &$isKnown ] );
4576
4577                 if ( !is_null( $isKnown ) ) {
4578                         return $isKnown;
4579                 }
4580
4581                 if ( $this->isExternal() ) {
4582                         return true; // any interwiki link might be viewable, for all we know
4583                 }
4584
4585                 switch ( $this->mNamespace ) {
4586                         case NS_MEDIA:
4587                         case NS_FILE:
4588                                 // file exists, possibly in a foreign repo
4589                                 return (bool)wfFindFile( $this );
4590                         case NS_SPECIAL:
4591                                 // valid special page
4592                                 return SpecialPageFactory::exists( $this->getDBkey() );
4593                         case NS_MAIN:
4594                                 // selflink, possibly with fragment
4595                                 return $this->mDbkeyform == '';
4596                         case NS_MEDIAWIKI:
4597                                 // known system message
4598                                 return $this->hasSourceText() !== false;
4599                         default:
4600                                 return false;
4601                 }
4602         }
4603
4604         /**
4605          * Does this title refer to a page that can (or might) be meaningfully
4606          * viewed?  In particular, this function may be used to determine if
4607          * links to the title should be rendered as "bluelinks" (as opposed to
4608          * "redlinks" to non-existent pages).
4609          * Adding something else to this function will cause inconsistency
4610          * since LinkHolderArray calls isAlwaysKnown() and does its own
4611          * page existence check.
4612          *
4613          * @return bool
4614          */
4615         public function isKnown() {
4616                 return $this->isAlwaysKnown() || $this->exists();
4617         }
4618
4619         /**
4620          * Does this page have source text?
4621          *
4622          * @return bool
4623          */
4624         public function hasSourceText() {
4625                 if ( $this->exists() ) {
4626                         return true;
4627                 }
4628
4629                 if ( $this->mNamespace == NS_MEDIAWIKI ) {
4630                         // If the page doesn't exist but is a known system message, default
4631                         // message content will be displayed, same for language subpages-
4632                         // Use always content language to avoid loading hundreds of languages
4633                         // to get the link color.
4634                         global $wgContLang;
4635                         list( $name, ) = MessageCache::singleton()->figureMessage(
4636                                 $wgContLang->lcfirst( $this->getText() )
4637                         );
4638                         $message = wfMessage( $name )->inLanguage( $wgContLang )->useDatabase( false );
4639                         return $message->exists();
4640                 }
4641
4642                 return false;
4643         }
4644
4645         /**
4646          * Get the default message text or false if the message doesn't exist
4647          *
4648          * @return string|bool
4649          */
4650         public function getDefaultMessageText() {
4651                 global $wgContLang;
4652
4653                 if ( $this->getNamespace() != NS_MEDIAWIKI ) { // Just in case
4654                         return false;
4655                 }
4656
4657                 list( $name, $lang ) = MessageCache::singleton()->figureMessage(
4658                         $wgContLang->lcfirst( $this->getText() )
4659                 );
4660                 $message = wfMessage( $name )->inLanguage( $lang )->useDatabase( false );
4661
4662                 if ( $message->exists() ) {
4663                         return $message->plain();
4664                 } else {
4665                         return false;
4666                 }
4667         }
4668
4669         /**
4670          * Updates page_touched for this page; called from LinksUpdate.php
4671          *
4672          * @param string $purgeTime [optional] TS_MW timestamp
4673          * @return bool True if the update succeeded
4674          */
4675         public function invalidateCache( $purgeTime = null ) {
4676                 if ( wfReadOnly() ) {
4677                         return false;
4678                 } elseif ( $this->mArticleID === 0 ) {
4679                         return true; // avoid gap locking if we know it's not there
4680                 }
4681
4682                 $dbw = wfGetDB( DB_MASTER );
4683                 $dbw->onTransactionPreCommitOrIdle( function () {
4684                         ResourceLoaderWikiModule::invalidateModuleCache( $this, null, null, wfWikiID() );
4685                 } );
4686
4687                 $conds = $this->pageCond();
4688                 DeferredUpdates::addUpdate(
4689                         new AutoCommitUpdate(
4690                                 $dbw,
4691                                 __METHOD__,
4692                                 function ( IDatabase $dbw, $fname ) use ( $conds, $purgeTime ) {
4693                                         $dbTimestamp = $dbw->timestamp( $purgeTime ?: time() );
4694                                         $dbw->update(
4695                                                 'page',
4696                                                 [ 'page_touched' => $dbTimestamp ],
4697                                                 $conds + [ 'page_touched < ' . $dbw->addQuotes( $dbTimestamp ) ],
4698                                                 $fname
4699                                         );
4700                                         MediaWikiServices::getInstance()->getLinkCache()->invalidateTitle( $this );
4701                                 }
4702                         ),
4703                         DeferredUpdates::PRESEND
4704                 );
4705
4706                 return true;
4707         }
4708
4709         /**
4710          * Update page_touched timestamps and send CDN purge messages for
4711          * pages linking to this title. May be sent to the job queue depending
4712          * on the number of links. Typically called on create and delete.
4713          */
4714         public function touchLinks() {
4715                 DeferredUpdates::addUpdate( new HTMLCacheUpdate( $this, 'pagelinks', 'page-touch' ) );
4716                 if ( $this->getNamespace() == NS_CATEGORY ) {
4717                         DeferredUpdates::addUpdate(
4718                                 new HTMLCacheUpdate( $this, 'categorylinks', 'category-touch' )
4719                         );
4720                 }
4721         }
4722
4723         /**
4724          * Get the last touched timestamp
4725          *
4726          * @param IDatabase|null $db
4727          * @return string|false Last-touched timestamp
4728          */
4729         public function getTouched( $db = null ) {
4730                 if ( $db === null ) {
4731                         $db = wfGetDB( DB_REPLICA );
4732                 }
4733                 $touched = $db->selectField( 'page', 'page_touched', $this->pageCond(), __METHOD__ );
4734                 return $touched;
4735         }
4736
4737         /**
4738          * Get the timestamp when this page was updated since the user last saw it.
4739          *
4740          * @param User $user
4741          * @return string|null
4742          */
4743         public function getNotificationTimestamp( $user = null ) {
4744                 global $wgUser;
4745
4746                 // Assume current user if none given
4747                 if ( !$user ) {
4748                         $user = $wgUser;
4749                 }
4750                 // Check cache first
4751                 $uid = $user->getId();
4752                 if ( !$uid ) {
4753                         return false;
4754                 }
4755                 // avoid isset here, as it'll return false for null entries
4756                 if ( array_key_exists( $uid, $this->mNotificationTimestamp ) ) {
4757                         return $this->mNotificationTimestamp[$uid];
4758                 }
4759                 // Don't cache too much!
4760                 if ( count( $this->mNotificationTimestamp ) >= self::CACHE_MAX ) {
4761                         $this->mNotificationTimestamp = [];
4762                 }
4763
4764                 $store = MediaWikiServices::getInstance()->getWatchedItemStore();
4765                 $watchedItem = $store->getWatchedItem( $user, $this );
4766                 if ( $watchedItem ) {
4767                         $this->mNotificationTimestamp[$uid] = $watchedItem->getNotificationTimestamp();
4768                 } else {
4769                         $this->mNotificationTimestamp[$uid] = false;
4770                 }
4771
4772                 return $this->mNotificationTimestamp[$uid];
4773         }
4774
4775         /**
4776          * Generate strings used for xml 'id' names in monobook tabs
4777          *
4778          * @param string $prepend Defaults to 'nstab-'
4779          * @return string XML 'id' name
4780          */
4781         public function getNamespaceKey( $prepend = 'nstab-' ) {
4782                 global $wgContLang;
4783                 // Gets the subject namespace if this title
4784                 $namespace = MWNamespace::getSubject( $this->getNamespace() );
4785                 // Checks if canonical namespace name exists for namespace
4786                 if ( MWNamespace::exists( $this->getNamespace() ) ) {
4787                         // Uses canonical namespace name
4788                         $namespaceKey = MWNamespace::getCanonicalName( $namespace );
4789                 } else {
4790                         // Uses text of namespace
4791                         $namespaceKey = $this->getSubjectNsText();
4792                 }
4793                 // Makes namespace key lowercase
4794                 $namespaceKey = $wgContLang->lc( $namespaceKey );
4795                 // Uses main
4796                 if ( $namespaceKey == '' ) {
4797                         $namespaceKey = 'main';
4798                 }
4799                 // Changes file to image for backwards compatibility
4800                 if ( $namespaceKey == 'file' ) {
4801                         $namespaceKey = 'image';
4802                 }
4803                 return $prepend . $namespaceKey;
4804         }
4805
4806         /**
4807          * Get all extant redirects to this Title
4808          *
4809          * @param int|null $ns Single namespace to consider; null to consider all namespaces
4810          * @return Title[] Array of Title redirects to this title
4811          */
4812         public function getRedirectsHere( $ns = null ) {
4813                 $redirs = [];
4814
4815                 $dbr = wfGetDB( DB_REPLICA );
4816                 $where = [
4817                         'rd_namespace' => $this->getNamespace(),
4818                         'rd_title' => $this->getDBkey(),
4819                         'rd_from = page_id'
4820                 ];
4821                 if ( $this->isExternal() ) {
4822                         $where['rd_interwiki'] = $this->getInterwiki();
4823                 } else {
4824                         $where[] = 'rd_interwiki = ' . $dbr->addQuotes( '' ) . ' OR rd_interwiki IS NULL';
4825                 }
4826                 if ( !is_null( $ns ) ) {
4827                         $where['page_namespace'] = $ns;
4828                 }
4829
4830                 $res = $dbr->select(
4831                         [ 'redirect', 'page' ],
4832                         [ 'page_namespace', 'page_title' ],
4833                         $where,
4834                         __METHOD__
4835                 );
4836
4837                 foreach ( $res as $row ) {
4838                         $redirs[] = self::newFromRow( $row );
4839                 }
4840                 return $redirs;
4841         }
4842
4843         /**
4844          * Check if this Title is a valid redirect target
4845          *
4846          * @return bool
4847          */
4848         public function isValidRedirectTarget() {
4849                 global $wgInvalidRedirectTargets;
4850
4851                 if ( $this->isSpecialPage() ) {
4852                         // invalid redirect targets are stored in a global array, but explicitly disallow Userlogout here
4853                         if ( $this->isSpecial( 'Userlogout' ) ) {
4854                                 return false;
4855                         }
4856
4857                         foreach ( $wgInvalidRedirectTargets as $target ) {
4858                                 if ( $this->isSpecial( $target ) ) {
4859                                         return false;
4860                                 }
4861                         }
4862                 }
4863
4864                 return true;
4865         }
4866
4867         /**
4868          * Get a backlink cache object
4869          *
4870          * @return BacklinkCache
4871          */
4872         public function getBacklinkCache() {
4873                 return BacklinkCache::get( $this );
4874         }
4875
4876         /**
4877          * Whether the magic words __INDEX__ and __NOINDEX__ function for this page.
4878          *
4879          * @return bool
4880          */
4881         public function canUseNoindex() {
4882                 global $wgExemptFromUserRobotsControl;
4883
4884                 $bannedNamespaces = is_null( $wgExemptFromUserRobotsControl )
4885                         ? MWNamespace::getContentNamespaces()
4886                         : $wgExemptFromUserRobotsControl;
4887
4888                 return !in_array( $this->mNamespace, $bannedNamespaces );
4889         }
4890
4891         /**
4892          * Returns the raw sort key to be used for categories, with the specified
4893          * prefix.  This will be fed to Collation::getSortKey() to get a
4894          * binary sortkey that can be used for actual sorting.
4895          *
4896          * @param string $prefix The prefix to be used, specified using
4897          *   {{defaultsort:}} or like [[Category:Foo|prefix]].  Empty for no
4898          *   prefix.
4899          * @return string
4900          */
4901         public function getCategorySortkey( $prefix = '' ) {
4902                 $unprefixed = $this->getText();
4903
4904                 // Anything that uses this hook should only depend
4905                 // on the Title object passed in, and should probably
4906                 // tell the users to run updateCollations.php --force
4907                 // in order to re-sort existing category relations.
4908                 Hooks::run( 'GetDefaultSortkey', [ $this, &$unprefixed ] );
4909                 if ( $prefix !== '' ) {
4910                         # Separate with a line feed, so the unprefixed part is only used as
4911                         # a tiebreaker when two pages have the exact same prefix.
4912                         # In UCA, tab is the only character that can sort above LF
4913                         # so we strip both of them from the original prefix.
4914                         $prefix = strtr( $prefix, "\n\t", '  ' );
4915                         return "$prefix\n$unprefixed";
4916                 }
4917                 return $unprefixed;
4918         }
4919
4920         /**
4921          * Returns the page language code saved in the database, if $wgPageLanguageUseDB is set
4922          * to true in LocalSettings.php, otherwise returns false. If there is no language saved in
4923          * the db, it will return NULL.
4924          *
4925          * @return string|null|bool
4926          */
4927         private function getDbPageLanguageCode() {
4928                 global $wgPageLanguageUseDB;
4929
4930                 // check, if the page language could be saved in the database, and if so and
4931                 // the value is not requested already, lookup the page language using LinkCache
4932                 if ( $wgPageLanguageUseDB && $this->mDbPageLanguage === false ) {
4933                         $linkCache = LinkCache::singleton();
4934                         $linkCache->addLinkObj( $this );
4935                         $this->mDbPageLanguage = $linkCache->getGoodLinkFieldObj( $this, 'lang' );
4936                 }
4937
4938                 return $this->mDbPageLanguage;
4939         }
4940
4941         /**
4942          * Get the language in which the content of this page is written in
4943          * wikitext. Defaults to $wgContLang, but in certain cases it can be
4944          * e.g. $wgLang (such as special pages, which are in the user language).
4945          *
4946          * @since 1.18
4947          * @return Language
4948          */
4949         public function getPageLanguage() {
4950                 global $wgLang, $wgLanguageCode;
4951                 if ( $this->isSpecialPage() ) {
4952                         // special pages are in the user language
4953                         return $wgLang;
4954                 }
4955
4956                 // Checking if DB language is set
4957                 $dbPageLanguage = $this->getDbPageLanguageCode();
4958                 if ( $dbPageLanguage ) {
4959                         return wfGetLangObj( $dbPageLanguage );
4960                 }
4961
4962                 if ( !$this->mPageLanguage || $this->mPageLanguage[1] !== $wgLanguageCode ) {
4963                         // Note that this may depend on user settings, so the cache should
4964                         // be only per-request.
4965                         // NOTE: ContentHandler::getPageLanguage() may need to load the
4966                         // content to determine the page language!
4967                         // Checking $wgLanguageCode hasn't changed for the benefit of unit
4968                         // tests.
4969                         $contentHandler = ContentHandler::getForTitle( $this );
4970                         $langObj = $contentHandler->getPageLanguage( $this );
4971                         $this->mPageLanguage = [ $langObj->getCode(), $wgLanguageCode ];
4972                 } else {
4973                         $langObj = wfGetLangObj( $this->mPageLanguage[0] );
4974                 }
4975
4976                 return $langObj;
4977         }
4978
4979         /**
4980          * Get the language in which the content of this page is written when
4981          * viewed by user. Defaults to $wgContLang, but in certain cases it can be
4982          * e.g. $wgLang (such as special pages, which are in the user language).
4983          *
4984          * @since 1.20
4985          * @return Language
4986          */
4987         public function getPageViewLanguage() {
4988                 global $wgLang;
4989
4990                 if ( $this->isSpecialPage() ) {
4991                         // If the user chooses a variant, the content is actually
4992                         // in a language whose code is the variant code.
4993                         $variant = $wgLang->getPreferredVariant();
4994                         if ( $wgLang->getCode() !== $variant ) {
4995                                 return Language::factory( $variant );
4996                         }
4997
4998                         return $wgLang;
4999                 }
5000
5001                 // Checking if DB language is set
5002                 $dbPageLanguage = $this->getDbPageLanguageCode();
5003                 if ( $dbPageLanguage ) {
5004                         $pageLang = wfGetLangObj( $dbPageLanguage );
5005                         $variant = $pageLang->getPreferredVariant();
5006                         if ( $pageLang->getCode() !== $variant ) {
5007                                 $pageLang = Language::factory( $variant );
5008                         }
5009
5010                         return $pageLang;
5011                 }
5012
5013                 // @note Can't be cached persistently, depends on user settings.
5014                 // @note ContentHandler::getPageViewLanguage() may need to load the
5015                 //   content to determine the page language!
5016                 $contentHandler = ContentHandler::getForTitle( $this );
5017                 $pageLang = $contentHandler->getPageViewLanguage( $this );
5018                 return $pageLang;
5019         }
5020
5021         /**
5022          * Get a list of rendered edit notices for this page.
5023          *
5024          * Array is keyed by the original message key, and values are rendered using parseAsBlock, so
5025          * they will already be wrapped in paragraphs.
5026          *
5027          * @since 1.21
5028          * @param int $oldid Revision ID that's being edited
5029          * @return array
5030          */
5031         public function getEditNotices( $oldid = 0 ) {
5032                 $notices = [];
5033
5034                 // Optional notice for the entire namespace
5035                 $editnotice_ns = 'editnotice-' . $this->getNamespace();
5036                 $msg = wfMessage( $editnotice_ns );
5037                 if ( $msg->exists() ) {
5038                         $html = $msg->parseAsBlock();
5039                         // Edit notices may have complex logic, but output nothing (T91715)
5040                         if ( trim( $html ) !== '' ) {
5041                                 $notices[$editnotice_ns] = Html::rawElement(
5042                                         'div',
5043                                         [ 'class' => [
5044                                                 'mw-editnotice',
5045                                                 'mw-editnotice-namespace',
5046                                                 Sanitizer::escapeClass( "mw-$editnotice_ns" )
5047                                         ] ],
5048                                         $html
5049                                 );
5050                         }
5051                 }
5052
5053                 if ( MWNamespace::hasSubpages( $this->getNamespace() ) ) {
5054                         // Optional notice for page itself and any parent page
5055                         $parts = explode( '/', $this->getDBkey() );
5056                         $editnotice_base = $editnotice_ns;
5057                         while ( count( $parts ) > 0 ) {
5058                                 $editnotice_base .= '-' . array_shift( $parts );
5059                                 $msg = wfMessage( $editnotice_base );
5060                                 if ( $msg->exists() ) {
5061                                         $html = $msg->parseAsBlock();
5062                                         if ( trim( $html ) !== '' ) {
5063                                                 $notices[$editnotice_base] = Html::rawElement(
5064                                                         'div',
5065                                                         [ 'class' => [
5066                                                                 'mw-editnotice',
5067                                                                 'mw-editnotice-base',
5068                                                                 Sanitizer::escapeClass( "mw-$editnotice_base" )
5069                                                         ] ],
5070                                                         $html
5071                                                 );
5072                                         }
5073                                 }
5074                         }
5075                 } else {
5076                         // Even if there are no subpages in namespace, we still don't want "/" in MediaWiki message keys
5077                         $editnoticeText = $editnotice_ns . '-' . strtr( $this->getDBkey(), '/', '-' );
5078                         $msg = wfMessage( $editnoticeText );
5079                         if ( $msg->exists() ) {
5080                                 $html = $msg->parseAsBlock();
5081                                 if ( trim( $html ) !== '' ) {
5082                                         $notices[$editnoticeText] = Html::rawElement(
5083                                                 'div',
5084                                                 [ 'class' => [
5085                                                         'mw-editnotice',
5086                                                         'mw-editnotice-page',
5087                                                         Sanitizer::escapeClass( "mw-$editnoticeText" )
5088                                                 ] ],
5089                                                 $html
5090                                         );
5091                                 }
5092                         }
5093                 }
5094
5095                 Hooks::run( 'TitleGetEditNotices', [ $this, $oldid, &$notices ] );
5096                 return $notices;
5097         }
5098
5099         /**
5100          * @return array
5101          */
5102         public function __sleep() {
5103                 return [
5104                         'mNamespace',
5105                         'mDbkeyform',
5106                         'mFragment',
5107                         'mInterwiki',
5108                         'mLocalInterwiki',
5109                         'mUserCaseDBKey',
5110                         'mDefaultNamespace',
5111                 ];
5112         }
5113
5114         public function __wakeup() {
5115                 $this->mArticleID = ( $this->mNamespace >= 0 ) ? -1 : 0;
5116                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
5117                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
5118         }
5119
5120 }