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