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 /**
  26  * Represents a title within MediaWiki.
  27  * Optionally may contain an interwiki designation or namespace.
  28  * @note This class can fetch various kinds of data from the database;
  29  *       however, it does so inefficiently.
  30  * @note Consider using a TitleValue object instead. TitleValue is more lightweight
  31  *       and does not rely on global state or the database.
  32  */
  33 class Title {
  34         /** @var MapCacheLRU */
  35         static private $titleCache = null;
  36
  37         /**
  38          * Title::newFromText maintains a cache to avoid expensive re-normalization of
  39          * commonly used titles. On a batch operation this can become a memory leak
  40          * if not bounded. After hitting this many titles reset the cache.
  41          */
  42         const CACHE_MAX = 1000;
  43
  44         /**
  45          * Used to be GAID_FOR_UPDATE define. Used with getArticleID() and friends
  46          * to use the master DB
  47          */
  48         const GAID_FOR_UPDATE = 1;
  49
  50         /**
  51          * @name Private member variables
  52          * Please use the accessor functions instead.
  53          * @private
  54          */
  55         // @{
  56
  57         /** @var string Text form (spaces not underscores) of the main part */
  58         public $mTextform = '';
  59
  60         /** @var string URL-encoded form of the main part */
  61         public $mUrlform = '';
  62
  63         /** @var string Main part with underscores */
  64         public $mDbkeyform = '';
  65
  66         /** @var string Database key with the initial letter in the case specified by the user */
  67         protected $mUserCaseDBKey;
  68
  69         /** @var int Namespace index, i.e. one of the NS_xxxx constants */
  70         public $mNamespace = NS_MAIN;
  71
  72         /** @var string Interwiki prefix */
  73         public $mInterwiki = '';
  74
  75         /** @var bool Was this Title created from a string with a local interwiki prefix? */
  76         private $mLocalInterwiki = false;
  77
  78         /** @var string Title fragment (i.e. the bit after the #) */
  79         public $mFragment = '';
  80
  81         /** @var int Article ID, fetched from the link cache on demand */
  82         public $mArticleID = -1;
  83
  84         /** @var bool|int ID of most recent revision */
  85         protected $mLatestID = false;
  86
  87         /**
  88          * @var bool|string ID of the page's content model, i.e. one of the
  89          *   CONTENT_MODEL_XXX constants
  90          */
  91         public $mContentModel = false;
  92
  93         /** @var int Estimated number of revisions; null of not loaded */
  94         private $mEstimateRevisions;
  95
  96         /** @var array Array of groups allowed to edit this article */
  97         public $mRestrictions = array();
  98
  99         /** @var string|bool */
 100         protected $mOldRestrictions = false;
 101
 102         /** @var bool Cascade restrictions on this page to included templates and images? */
 103         public $mCascadeRestriction;
 104
 105         /** Caching the results of getCascadeProtectionSources */
 106         public $mCascadingRestrictions;
 107
 108         /** @var array When do the restrictions on this page expire? */
 109         protected $mRestrictionsExpiry = array();
 110
 111         /** @var bool Are cascading restrictions in effect on this page? */
 112         protected $mHasCascadingRestrictions;
 113
 114         /** @var array Where are the cascading restrictions coming from on this page? */
 115         public $mCascadeSources;
 116
 117         /** @var bool Boolean for initialisation on demand */
 118         public $mRestrictionsLoaded = false;
 119
 120         /** @var string Text form including namespace/interwiki, initialised on demand */
 121         protected $mPrefixedText = null;
 122
 123         /** @var mixed Cached value for getTitleProtection (create protection) */
 124         public $mTitleProtection;
 125
 126         /**
 127          * @var int Namespace index when there is no namespace. Don't change the
 128          *   following default, NS_MAIN is hardcoded in several places. See bug 696.
 129          *   Zero except in {{transclusion}} tags.
 130          */
 131         public $mDefaultNamespace = NS_MAIN;
 132
 133         /**
 134          * @var bool Is $wgUser watching this page? null if unfilled, accessed
 135          * through userIsWatching()
 136          */
 137         protected $mWatched = null;
 138
 139         /** @var int The page length, 0 for special pages */
 140         protected $mLength = -1;
 141
 142         /** @var null Is the article at this title a redirect? */
 143         public $mRedirect = null;
 144
 145         /** @var array Associative array of user ID -> timestamp/false */
 146         private $mNotificationTimestamp = array();
 147
 148         /** @var bool Whether a page has any subpages */
 149         private $mHasSubpages;
 150
 151         /** @var bool The (string) language code of the page's language and content code. */
 152         private $mPageLanguage = false;
 153
 154         /** @var string The page language code from the database */
 155         private $mDbPageLanguage = null;
 156
 157         /** @var TitleValue A corresponding TitleValue object */
 158         private $mTitleValue = null;
 159
 160         /** @var bool Would deleting this page be a big deletion? */
 161         private $mIsBigDeletion = null;
 162         // @}
 163
 164         /**
 165          * B/C kludge: provide a TitleParser for use by Title.
 166          * Ideally, Title would have no methods that need this.
 167          * Avoid usage of this singleton by using TitleValue
 168          * and the associated services when possible.
 169          *
 170          * @return TitleParser
 171          */
 172         private static function getTitleParser() {
 173                 global $wgContLang, $wgLocalInterwikis;
 174
 175                 static $titleCodec = null;
 176                 static $titleCodecFingerprint = null;
 177
 178                 // $wgContLang and $wgLocalInterwikis may change (especially while testing),
 179                 // make sure we are using the right one. To detect changes over the course
 180                 // of a request, we remember a fingerprint of the config used to create the
 181                 // codec singleton, and re-create it if the fingerprint doesn't match.
 182                 $fingerprint = spl_object_hash( $wgContLang ) . '|' . join( '+', $wgLocalInterwikis );
 183
 184                 if ( $fingerprint !== $titleCodecFingerprint ) {
 185                         $titleCodec = null;
 186                 }
 187
 188                 if ( !$titleCodec ) {
 189                         $titleCodec = new MediaWikiTitleCodec(
 190                                 $wgContLang,
 191                                 GenderCache::singleton(),
 192                                 $wgLocalInterwikis
 193                         );
 194                         $titleCodecFingerprint = $fingerprint;
 195                 }
 196
 197                 return $titleCodec;
 198         }
 199
 200         /**
 201          * B/C kludge: provide a TitleParser for use by Title.
 202          * Ideally, Title would have no methods that need this.
 203          * Avoid usage of this singleton by using TitleValue
 204          * and the associated services when possible.
 205          *
 206          * @return TitleFormatter
 207          */
 208         private static function getTitleFormatter() {
 209                 // NOTE: we know that getTitleParser() returns a MediaWikiTitleCodec,
 210                 //      which implements TitleFormatter.
 211                 return self::getTitleParser();
 212         }
 213
 214         function __construct() {
 215         }
 216
 217         /**
 218          * Create a new Title from a prefixed DB key
 219          *
 220          * @param string $key The database key, which has underscores
 221          *      instead of spaces, possibly including namespace and
 222          *      interwiki prefixes
 223          * @return Title|null Title, or null on an error
 224          */
 225         public static function newFromDBkey( $key ) {
 226                 $t = new Title();
 227                 $t->mDbkeyform = $key;
 228
 229                 try {
 230                         $t->secureAndSplit();
 231                         return $t;
 232                 } catch ( MalformedTitleException $ex ) {
 233                         return null;
 234                 }
 235         }
 236
 237         /**
 238          * Create a new Title from a TitleValue
 239          *
 240          * @param TitleValue $titleValue Assumed to be safe.
 241          *
 242          * @return Title
 243          */
 244         public static function newFromTitleValue( TitleValue $titleValue ) {
 245                 return self::makeTitle(
 246                         $titleValue->getNamespace(),
 247                         $titleValue->getText(),
 248                         $titleValue->getFragment() );
 249         }
 250
 251         /**
 252          * Create a new Title from text, such as what one would find in a link. De-
 253          * codes any HTML entities in the text.
 254          *
 255          * @param string $text The link text; spaces, prefixes, and an
 256          *   initial ':' indicating the main namespace are accepted.
 257          * @param int $defaultNamespace The namespace to use if none is specified
 258          *   by a prefix.  If you want to force a specific namespace even if
 259          *   $text might begin with a namespace prefix, use makeTitle() or
 260          *   makeTitleSafe().
 261          * @throws InvalidArgumentException
 262          * @return Title|null Title or null on an error.
 263          */
 264         public static function newFromText( $text, $defaultNamespace = NS_MAIN ) {
 265                 if ( is_object( $text ) ) {
 266                         throw new InvalidArgumentException( '$text must be a string.' );
 267                 } elseif ( !is_string( $text ) ) {
 268                         wfDebugLog( 'T76305', wfGetAllCallers( 5 ) );
 269                         wfWarn(
 270                                 __METHOD__ . ': $text must be a string. ' .
 271                                         'This will throw an InvalidArgumentException in future.',
 272                                 2
 273                         );
 274                 }
 275
 276                 try {
 277                         return Title::newFromTextThrow( $text, $defaultNamespace );
 278                 } catch ( MalformedTitleException $ex ) {
 279                         return null;
 280                 }
 281         }
 282
 283         /**
 284          * Like Title::newFromText(), but throws MalformedTitleException when the title is invalid,
 285          * rather than returning null.
 286          *
 287          * The exception subclasses encode detailed information about why the title is invalid.
 288          *
 289          * @see Title::newFromText
 290          *
 291          * @since 1.25
 292          * @param string $text Title text to check
 293          * @param int $defaultNamespace
 294          * @throws MalformedTitleException If the title is invalid
 295          * @return Title
 296          */
 297         public static function newFromTextThrow( $text, $defaultNamespace = NS_MAIN ) {
 298                 if ( is_object( $text ) ) {
 299                         throw new MWException( 'Title::newFromTextThrow given an object' );
 300                 }
 301
 302                 $cache = self::getTitleCache();
 303
 304                 /**
 305                  * Wiki pages often contain multiple links to the same page.
 306                  * Title normalization and parsing can become expensive on
 307                  * pages with many links, so we can save a little time by
 308                  * caching them.
 309                  *
 310                  * In theory these are value objects and won't get changed...
 311                  */
 312                 if ( $defaultNamespace == NS_MAIN && $cache->has( $text ) ) {
 313                         return $cache->get( $text );
 314                 }
 315
 316                 # Convert things like &eacute; &#257; or &#x3017; into normalized (bug 14952) text
 317                 $filteredText = Sanitizer::decodeCharReferencesAndNormalize( $text );
 318
 319                 $t = new Title();
 320                 $t->mDbkeyform = strtr( $filteredText, ' ', '_' );
 321                 $t->mDefaultNamespace = intval( $defaultNamespace );
 322
 323                 $t->secureAndSplit();
 324                 if ( $defaultNamespace == NS_MAIN ) {
 325                         $cache->set( $text, $t );
 326                 }
 327                 return $t;
 328         }
 329
 330         /**
 331          * THIS IS NOT THE FUNCTION YOU WANT. Use Title::newFromText().
 332          *
 333          * Example of wrong and broken code:
 334          * $title = Title::newFromURL( $wgRequest->getVal( 'title' ) );
 335          *
 336          * Example of right code:
 337          * $title = Title::newFromText( $wgRequest->getVal( 'title' ) );
 338          *
 339          * Create a new Title from URL-encoded text. Ensures that
 340          * the given title's length does not exceed the maximum.
 341          *
 342          * @param string $url The title, as might be taken from a URL
 343          * @return Title|null The new object, or null on an error
 344          */
 345         public static function newFromURL( $url ) {
 346                 $t = new Title();
 347
 348                 # For compatibility with old buggy URLs. "+" is usually not valid in titles,
 349                 # but some URLs used it as a space replacement and they still come
 350                 # from some external search tools.
 351                 if ( strpos( self::legalChars(), '+' ) === false ) {
 352                         $url = strtr( $url, '+', ' ' );
 353                 }
 354
 355                 $t->mDbkeyform = strtr( $url, ' ', '_' );
 356
 357                 try {
 358                         $t->secureAndSplit();
 359                         return $t;
 360                 } catch ( MalformedTitleException $ex ) {
 361                         return null;
 362                 }
 363         }
 364
 365         /**
 366          * @return MapCacheLRU
 367          */
 368         private static function getTitleCache() {
 369                 if ( self::$titleCache == null ) {
 370                         self::$titleCache = new MapCacheLRU( self::CACHE_MAX );
 371                 }
 372                 return self::$titleCache;
 373         }
 374
 375         /**
 376          * Returns a list of fields that are to be selected for initializing Title
 377          * objects or LinkCache entries. Uses $wgContentHandlerUseDB to determine
 378          * whether to include page_content_model.
 379          *
 380          * @return array
 381          */
 382         protected static function getSelectFields() {
 383                 global $wgContentHandlerUseDB;
 384
 385                 $fields = array(
 386                         'page_namespace', 'page_title', 'page_id',
 387                         'page_len', 'page_is_redirect', 'page_latest',
 388                 );
 389
 390                 if ( $wgContentHandlerUseDB ) {
 391                         $fields[] = 'page_content_model';
 392                 }
 393
 394                 return $fields;
 395         }
 396
 397         /**
 398          * Create a new Title from an article ID
 399          *
 400          * @param int $id The page_id corresponding to the Title to create
 401          * @param int $flags Use Title::GAID_FOR_UPDATE to use master
 402          * @return Title|null The new object, or null on an error
 403          */
 404         public static function newFromID( $id, $flags = 0 ) {
 405                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
 406                 $row = $db->selectRow(
 407                         'page',
 408                         self::getSelectFields(),
 409                         array( 'page_id' => $id ),
 410                         __METHOD__
 411                 );
 412                 if ( $row !== false ) {
 413                         $title = Title::newFromRow( $row );
 414                 } else {
 415                         $title = null;
 416                 }
 417                 return $title;
 418         }
 419
 420         /**
 421          * Make an array of titles from an array of IDs
 422          *
 423          * @param int[] $ids Array of IDs
 424          * @return Title[] Array of Titles
 425          */
 426         public static function newFromIDs( $ids ) {
 427                 if ( !count( $ids ) ) {
 428                         return array();
 429                 }
 430                 $dbr = wfGetDB( DB_SLAVE );
 431
 432                 $res = $dbr->select(
 433                         'page',
 434                         self::getSelectFields(),
 435                         array( 'page_id' => $ids ),
 436                         __METHOD__
 437                 );
 438
 439                 $titles = array();
 440                 foreach ( $res as $row ) {
 441                         $titles[] = Title::newFromRow( $row );
 442                 }
 443                 return $titles;
 444         }
 445
 446         /**
 447          * Make a Title object from a DB row
 448          *
 449          * @param stdClass $row Object database row (needs at least page_title,page_namespace)
 450          * @return Title Corresponding Title
 451          */
 452         public static function newFromRow( $row ) {
 453                 $t = self::makeTitle( $row->page_namespace, $row->page_title );
 454                 $t->loadFromRow( $row );
 455                 return $t;
 456         }
 457
 458         /**
 459          * Load Title object fields from a DB row.
 460          * If false is given, the title will be treated as non-existing.
 461          *
 462          * @param stdClass|bool $row Database row
 463          */
 464         public function loadFromRow( $row ) {
 465                 if ( $row ) { // page found
 466                         if ( isset( $row->page_id ) ) {
 467                                 $this->mArticleID = (int)$row->page_id;
 468                         }
 469                         if ( isset( $row->page_len ) ) {
 470                                 $this->mLength = (int)$row->page_len;
 471                         }
 472                         if ( isset( $row->page_is_redirect ) ) {
 473                                 $this->mRedirect = (bool)$row->page_is_redirect;
 474                         }
 475                         if ( isset( $row->page_latest ) ) {
 476                                 $this->mLatestID = (int)$row->page_latest;
 477                         }
 478                         if ( isset( $row->page_content_model ) ) {
 479                                 $this->mContentModel = strval( $row->page_content_model );
 480                         } else {
 481                                 $this->mContentModel = false; # initialized lazily in getContentModel()
 482                         }
 483                         if ( isset( $row->page_lang ) ) {
 484                                 $this->mDbPageLanguage = (string)$row->page_lang;
 485                         }
 486                         if ( isset( $row->page_restrictions ) ) {
 487                                 $this->mOldRestrictions = $row->page_restrictions;
 488                         }
 489                 } else { // page not found
 490                         $this->mArticleID = 0;
 491                         $this->mLength = 0;
 492                         $this->mRedirect = false;
 493                         $this->mLatestID = 0;
 494                         $this->mContentModel = false; # initialized lazily in getContentModel()
 495                 }
 496         }
 497
 498         /**
 499          * Create a new Title from a namespace index and a DB key.
 500          * It's assumed that $ns and $title are *valid*, for instance when
 501          * they came directly from the database or a special page name.
 502          * For convenience, spaces are converted to underscores so that
 503          * eg user_text fields can be used directly.
 504          *
 505          * @param int $ns The namespace of the article
 506          * @param string $title The unprefixed database key form
 507          * @param string $fragment The link fragment (after the "#")
 508          * @param string $interwiki The interwiki prefix
 509          * @return Title The new object
 510          */
 511         public static function &makeTitle( $ns, $title, $fragment = '', $interwiki = '' ) {
 512                 $t = new Title();
 513                 $t->mInterwiki = $interwiki;
 514                 $t->mFragment = $fragment;
 515                 $t->mNamespace = $ns = intval( $ns );
 516                 $t->mDbkeyform = strtr( $title, ' ', '_' );
 517                 $t->mArticleID = ( $ns >= 0 ) ? -1 : 0;
 518                 $t->mUrlform = wfUrlencode( $t->mDbkeyform );
 519                 $t->mTextform = strtr( $title, '_', ' ' );
 520                 $t->mContentModel = false; # initialized lazily in getContentModel()
 521                 return $t;
 522         }
 523
 524         /**
 525          * Create a new Title from a namespace index and a DB key.
 526          * The parameters will be checked for validity, which is a bit slower
 527          * than makeTitle() but safer for user-provided data.
 528          *
 529          * @param int $ns The namespace of the article
 530          * @param string $title Database key form
 531          * @param string $fragment The link fragment (after the "#")
 532          * @param string $interwiki Interwiki prefix
 533          * @return Title|null The new object, or null on an error
 534          */
 535         public static function makeTitleSafe( $ns, $title, $fragment = '', $interwiki = '' ) {
 536                 if ( !MWNamespace::exists( $ns ) ) {
 537                         return null;
 538                 }
 539
 540                 $t = new Title();
 541                 $t->mDbkeyform = Title::makeName( $ns, $title, $fragment, $interwiki, true );
 542
 543                 try {
 544                         $t->secureAndSplit();
 545                         return $t;
 546                 } catch ( MalformedTitleException $ex ) {
 547                         return null;
 548                 }
 549         }
 550
 551         /**
 552          * Create a new Title for the Main Page
 553          *
 554          * @return Title The new object
 555          */
 556         public static function newMainPage() {
 557                 $title = Title::newFromText( wfMessage( 'mainpage' )->inContentLanguage()->text() );
 558                 // Don't give fatal errors if the message is broken
 559                 if ( !$title ) {
 560                         $title = Title::newFromText( 'Main Page' );
 561                 }
 562                 return $title;
 563         }
 564
 565         /**
 566          * Extract a redirect destination from a string and return the
 567          * Title, or null if the text doesn't contain a valid redirect
 568          * This will only return the very next target, useful for
 569          * the redirect table and other checks that don't need full recursion
 570          *
 571          * @param string $text Text with possible redirect
 572          * @return Title The corresponding Title
 573          * @deprecated since 1.21, use Content::getRedirectTarget instead.
 574          */
 575         public static function newFromRedirect( $text ) {
 576                 ContentHandler::deprecated( __METHOD__, '1.21' );
 577
 578                 $content = ContentHandler::makeContent( $text, null, CONTENT_MODEL_WIKITEXT );
 579                 return $content->getRedirectTarget();
 580         }
 581
 582         /**
 583          * Extract a redirect destination from a string and return the
 584          * Title, or null if the text doesn't contain a valid redirect
 585          * This will recurse down $wgMaxRedirects times or until a non-redirect target is hit
 586          * in order to provide (hopefully) the Title of the final destination instead of another redirect
 587          *
 588          * @param string $text Text with possible redirect
 589          * @return Title
 590          * @deprecated since 1.21, use Content::getUltimateRedirectTarget instead.
 591          */
 592         public static function newFromRedirectRecurse( $text ) {
 593                 ContentHandler::deprecated( __METHOD__, '1.21' );
 594
 595                 $content = ContentHandler::makeContent( $text, null, CONTENT_MODEL_WIKITEXT );
 596                 return $content->getUltimateRedirectTarget();
 597         }
 598
 599         /**
 600          * Extract a redirect destination from a string and return an
 601          * array of Titles, or null if the text doesn't contain a valid redirect
 602          * The last element in the array is the final destination after all redirects
 603          * have been resolved (up to $wgMaxRedirects times)
 604          *
 605          * @param string $text Text with possible redirect
 606          * @return Title[] Array of Titles, with the destination last
 607          * @deprecated since 1.21, use Content::getRedirectChain instead.
 608          */
 609         public static function newFromRedirectArray( $text ) {
 610                 ContentHandler::deprecated( __METHOD__, '1.21' );
 611
 612                 $content = ContentHandler::makeContent( $text, null, CONTENT_MODEL_WIKITEXT );
 613                 return $content->getRedirectChain();
 614         }
 615
 616         /**
 617          * Get the prefixed DB key associated with an ID
 618          *
 619          * @param int $id The page_id of the article
 620          * @return Title|null An object representing the article, or null if no such article was found
 621          */
 622         public static function nameOf( $id ) {
 623                 $dbr = wfGetDB( DB_SLAVE );
 624
 625                 $s = $dbr->selectRow(
 626                         'page',
 627                         array( 'page_namespace', 'page_title' ),
 628                         array( 'page_id' => $id ),
 629                         __METHOD__
 630                 );
 631                 if ( $s === false ) {
 632                         return null;
 633                 }
 634
 635                 $n = self::makeName( $s->page_namespace, $s->page_title );
 636                 return $n;
 637         }
 638
 639         /**
 640          * Get a regex character class describing the legal characters in a link
 641          *
 642          * @return string The list of characters, not delimited
 643          */
 644         public static function legalChars() {
 645                 global $wgLegalTitleChars;
 646                 return $wgLegalTitleChars;
 647         }
 648
 649         /**
 650          * Returns a simple regex that will match on characters and sequences invalid in titles.
 651          * Note that this doesn't pick up many things that could be wrong with titles, but that
 652          * replacing this regex with something valid will make many titles valid.
 653          *
 654          * @deprecated since 1.25, use MediaWikiTitleCodec::getTitleInvalidRegex() instead
 655          *
 656          * @return string Regex string
 657          */
 658         static function getTitleInvalidRegex() {
 659                 wfDeprecated( __METHOD__, '1.25' );
 660                 return MediaWikiTitleCodec::getTitleInvalidRegex();
 661         }
 662
 663         /**
 664          * Utility method for converting a character sequence from bytes to Unicode.
 665          *
 666          * Primary usecase being converting $wgLegalTitleChars to a sequence usable in
 667          * javascript, as PHP uses UTF-8 bytes where javascript uses Unicode code units.
 668          *
 669          * @param string $byteClass
 670          * @return string
 671          */
 672         public static function convertByteClassToUnicodeClass( $byteClass ) {
 673                 $length = strlen( $byteClass );
 674                 // Input token queue
 675                 $x0 = $x1 = $x2 = '';
 676                 // Decoded queue
 677                 $d0 = $d1 = $d2 = '';
 678                 // Decoded integer codepoints
 679                 $ord0 = $ord1 = $ord2 = 0;
 680                 // Re-encoded queue
 681                 $r0 = $r1 = $r2 = '';
 682                 // Output
 683                 $out = '';
 684                 // Flags
 685                 $allowUnicode = false;
 686                 for ( $pos = 0; $pos < $length; $pos++ ) {
 687                         // Shift the queues down
 688                         $x2 = $x1;
 689                         $x1 = $x0;
 690                         $d2 = $d1;
 691                         $d1 = $d0;
 692                         $ord2 = $ord1;
 693                         $ord1 = $ord0;
 694                         $r2 = $r1;
 695                         $r1 = $r0;
 696                         // Load the current input token and decoded values
 697                         $inChar = $byteClass[$pos];
 698                         if ( $inChar == '\\' ) {
 699                                 if ( preg_match( '/x([0-9a-fA-F]{2})/A', $byteClass, $m, 0, $pos + 1 ) ) {
 700                                         $x0 = $inChar . $m[0];
 701                                         $d0 = chr( hexdec( $m[1] ) );
 702                                         $pos += strlen( $m[0] );
 703                                 } elseif ( preg_match( '/[0-7]{3}/A', $byteClass, $m, 0, $pos + 1 ) ) {
 704                                         $x0 = $inChar . $m[0];
 705                                         $d0 = chr( octdec( $m[0] ) );
 706                                         $pos += strlen( $m[0] );
 707                                 } elseif ( $pos + 1 >= $length ) {
 708                                         $x0 = $d0 = '\\';
 709                                 } else {
 710                                         $d0 = $byteClass[$pos + 1];
 711                                         $x0 = $inChar . $d0;
 712                                         $pos += 1;
 713                                 }
 714                         } else {
 715                                 $x0 = $d0 = $inChar;
 716                         }
 717                         $ord0 = ord( $d0 );
 718                         // Load the current re-encoded value
 719                         if ( $ord0 < 32 || $ord0 == 0x7f ) {
 720                                 $r0 = sprintf( '\x%02x', $ord0 );
 721                         } elseif ( $ord0 >= 0x80 ) {
 722                                 // Allow unicode if a single high-bit character appears
 723                                 $r0 = sprintf( '\x%02x', $ord0 );
 724                                 $allowUnicode = true;
 725                         } elseif ( strpos( '-\\[]^', $d0 ) !== false ) {
 726                                 $r0 = '\\' . $d0;
 727                         } else {
 728                                 $r0 = $d0;
 729                         }
 730                         // Do the output
 731                         if ( $x0 !== '' && $x1 === '-' && $x2 !== '' ) {
 732                                 // Range
 733                                 if ( $ord2 > $ord0 ) {
 734                                         // Empty range
 735                                 } elseif ( $ord0 >= 0x80 ) {
 736                                         // Unicode range
 737                                         $allowUnicode = true;
 738                                         if ( $ord2 < 0x80 ) {
 739                                                 // Keep the non-unicode section of the range
 740                                                 $out .= "$r2-\\x7F";
 741                                         }
 742                                 } else {
 743                                         // Normal range
 744                                         $out .= "$r2-$r0";
 745                                 }
 746                                 // Reset state to the initial value
 747                                 $x0 = $x1 = $d0 = $d1 = $r0 = $r1 = '';
 748                         } elseif ( $ord2 < 0x80 ) {
 749                                 // ASCII character
 750                                 $out .= $r2;
 751                         }
 752                 }
 753                 if ( $ord1 < 0x80 ) {
 754                         $out .= $r1;
 755                 }
 756                 if ( $ord0 < 0x80 ) {
 757                         $out .= $r0;
 758                 }
 759                 if ( $allowUnicode ) {
 760                         $out .= '\u0080-\uFFFF';
 761                 }
 762                 return $out;
 763         }
 764
 765         /**
 766          * Make a prefixed DB key from a DB key and a namespace index
 767          *
 768          * @param int $ns Numerical representation of the namespace
 769          * @param string $title The DB key form the title
 770          * @param string $fragment The link fragment (after the "#")
 771          * @param string $interwiki The interwiki prefix
 772          * @param bool $canoncialNamespace If true, use the canonical name for
 773          *   $ns instead of the localized version.
 774          * @return string The prefixed form of the title
 775          */
 776         public static function makeName( $ns, $title, $fragment = '', $interwiki = '',
 777                 $canoncialNamespace = false
 778         ) {
 779                 global $wgContLang;
 780
 781                 if ( $canoncialNamespace ) {
 782                         $namespace = MWNamespace::getCanonicalName( $ns );
 783                 } else {
 784                         $namespace = $wgContLang->getNsText( $ns );
 785                 }
 786                 $name = $namespace == '' ? $title : "$namespace:$title";
 787                 if ( strval( $interwiki ) != '' ) {
 788                         $name = "$interwiki:$name";
 789                 }
 790                 if ( strval( $fragment ) != '' ) {
 791                         $name .= '#' . $fragment;
 792                 }
 793                 return $name;
 794         }
 795
 796         /**
 797          * Escape a text fragment, say from a link, for a URL
 798          *
 799          * @param string $fragment Containing a URL or link fragment (after the "#")
 800          * @return string Escaped string
 801          */
 802         static function escapeFragmentForURL( $fragment ) {
 803                 # Note that we don't urlencode the fragment.  urlencoded Unicode
 804                 # fragments appear not to work in IE (at least up to 7) or in at least
 805                 # one version of Opera 9.x.  The W3C validator, for one, doesn't seem
 806                 # to care if they aren't encoded.
 807                 return Sanitizer::escapeId( $fragment, 'noninitial' );
 808         }
 809
 810         /**
 811          * Callback for usort() to do title sorts by (namespace, title)
 812          *
 813          * @param Title $a
 814          * @param Title $b
 815          *
 816          * @return int Result of string comparison, or namespace comparison
 817          */
 818         public static function compare( $a, $b ) {
 819                 if ( $a->getNamespace() == $b->getNamespace() ) {
 820                         return strcmp( $a->getText(), $b->getText() );
 821                 } else {
 822                         return $a->getNamespace() - $b->getNamespace();
 823                 }
 824         }
 825
 826         /**
 827          * Determine whether the object refers to a page within
 828          * this project (either this wiki or a wiki with a local
 829          * interwiki, see https://www.mediawiki.org/wiki/Manual:Interwiki_table#iw_local )
 830          *
 831          * @return bool True if this is an in-project interwiki link or a wikilink, false otherwise
 832          */
 833         public function isLocal() {
 834                 if ( $this->isExternal() ) {
 835                         $iw = Interwiki::fetch( $this->mInterwiki );
 836                         if ( $iw ) {
 837                                 return $iw->isLocal();
 838                         }
 839                 }
 840                 return true;
 841         }
 842
 843         /**
 844          * Is this Title interwiki?
 845          *
 846          * @return bool
 847          */
 848         public function isExternal() {
 849                 return $this->mInterwiki !== '';
 850         }
 851
 852         /**
 853          * Get the interwiki prefix
 854          *
 855          * Use Title::isExternal to check if a interwiki is set
 856          *
 857          * @return string Interwiki prefix
 858          */
 859         public function getInterwiki() {
 860                 return $this->mInterwiki;
 861         }
 862
 863         /**
 864          * Was this a local interwiki link?
 865          *
 866          * @return bool
 867          */
 868         public function wasLocalInterwiki() {
 869                 return $this->mLocalInterwiki;
 870         }
 871
 872         /**
 873          * Determine whether the object refers to a page within
 874          * this project and is transcludable.
 875          *
 876          * @return bool True if this is transcludable
 877          */
 878         public function isTrans() {
 879                 if ( !$this->isExternal() ) {
 880                         return false;
 881                 }
 882
 883                 return Interwiki::fetch( $this->mInterwiki )->isTranscludable();
 884         }
 885
 886         /**
 887          * Returns the DB name of the distant wiki which owns the object.
 888          *
 889          * @return string The DB name
 890          */
 891         public function getTransWikiID() {
 892                 if ( !$this->isExternal() ) {
 893                         return false;
 894                 }
 895
 896                 return Interwiki::fetch( $this->mInterwiki )->getWikiID();
 897         }
 898
 899         /**
 900          * Get a TitleValue object representing this Title.
 901          *
 902          * @note Not all valid Titles have a corresponding valid TitleValue
 903          * (e.g. TitleValues cannot represent page-local links that have a
 904          * fragment but no title text).
 905          *
 906          * @return TitleValue|null
 907          */
 908         public function getTitleValue() {
 909                 if ( $this->mTitleValue === null ) {
 910                         try {
 911                                 $this->mTitleValue = new TitleValue(
 912                                         $this->getNamespace(),
 913                                         $this->getDBkey(),
 914                                         $this->getFragment() );
 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->mContentModel && $this->getArticleID( $flags ) ) {
 982                         $linkCache = LinkCache::singleton();
 983                         $linkCache->addLinkObj( $this ); # in case we already had an article ID
 984                         $this->mContentModel = $linkCache->getGoodLinkFieldObj( $this, 'model' );
 985                 }
 986
 987                 if ( !$this->mContentModel ) {
 988                         $this->mContentModel = ContentHandler::getDefaultModelFor( $this );
 989                 }
 990
 991                 return $this->mContentModel;
 992         }
 993
 994         /**
 995          * Convenience method for checking a title's content model name
 996          *
 997          * @param string $id The content model ID (use the CONTENT_MODEL_XXX constants).
 998          * @return bool True if $this->getContentModel() == $id
 999          */
1000         public function hasContentModel( $id ) {
1001                 return $this->getContentModel() == $id;
1002         }
1003
1004         /**
1005          * Get the namespace text
1006          *
1007          * @return string Namespace text
1008          */
1009         public function getNsText() {
1010                 if ( $this->isExternal() ) {
1011                         // This probably shouldn't even happen,
1012                         // but for interwiki transclusion it sometimes does.
1013                         // Use the canonical namespaces if possible to try to
1014                         // resolve a foreign namespace.
1015                         if ( MWNamespace::exists( $this->mNamespace ) ) {
1016                                 return MWNamespace::getCanonicalName( $this->mNamespace );
1017                         }
1018                 }
1019
1020                 try {
1021                         $formatter = self::getTitleFormatter();
1022                         return $formatter->getNamespaceName( $this->mNamespace, $this->mDbkeyform );
1023                 } catch ( InvalidArgumentException $ex ) {
1024                         wfDebug( __METHOD__ . ': ' . $ex->getMessage() . "\n" );
1025                         return false;
1026                 }
1027         }
1028
1029         /**
1030          * Get the namespace text of the subject (rather than talk) page
1031          *
1032          * @return string Namespace text
1033          */
1034         public function getSubjectNsText() {
1035                 global $wgContLang;
1036                 return $wgContLang->getNsText( MWNamespace::getSubject( $this->mNamespace ) );
1037         }
1038
1039         /**
1040          * Get the namespace text of the talk page
1041          *
1042          * @return string Namespace text
1043          */
1044         public function getTalkNsText() {
1045                 global $wgContLang;
1046                 return $wgContLang->getNsText( MWNamespace::getTalk( $this->mNamespace ) );
1047         }
1048
1049         /**
1050          * Could this title have a corresponding talk page?
1051          *
1052          * @return bool
1053          */
1054         public function canTalk() {
1055                 return MWNamespace::canTalk( $this->mNamespace );
1056         }
1057
1058         /**
1059          * Is this in a namespace that allows actual pages?
1060          *
1061          * @return bool
1062          */
1063         public function canExist() {
1064                 return $this->mNamespace >= NS_MAIN;
1065         }
1066
1067         /**
1068          * Can this title be added to a user's watchlist?
1069          *
1070          * @return bool
1071          */
1072         public function isWatchable() {
1073                 return !$this->isExternal() && MWNamespace::isWatchable( $this->getNamespace() );
1074         }
1075
1076         /**
1077          * Returns true if this is a special page.
1078          *
1079          * @return bool
1080          */
1081         public function isSpecialPage() {
1082                 return $this->getNamespace() == NS_SPECIAL;
1083         }
1084
1085         /**
1086          * Returns true if this title resolves to the named special page
1087          *
1088          * @param string $name The special page name
1089          * @return bool
1090          */
1091         public function isSpecial( $name ) {
1092                 if ( $this->isSpecialPage() ) {
1093                         list( $thisName, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $this->getDBkey() );
1094                         if ( $name == $thisName ) {
1095                                 return true;
1096                         }
1097                 }
1098                 return false;
1099         }
1100
1101         /**
1102          * If the Title refers to a special page alias which is not the local default, resolve
1103          * the alias, and localise the name as necessary.  Otherwise, return $this
1104          *
1105          * @return Title
1106          */
1107         public function fixSpecialName() {
1108                 if ( $this->isSpecialPage() ) {
1109                         list( $canonicalName, $par ) = SpecialPageFactory::resolveAlias( $this->mDbkeyform );
1110                         if ( $canonicalName ) {
1111                                 $localName = SpecialPageFactory::getLocalNameFor( $canonicalName, $par );
1112                                 if ( $localName != $this->mDbkeyform ) {
1113                                         return Title::makeTitle( NS_SPECIAL, $localName );
1114                                 }
1115                         }
1116                 }
1117                 return $this;
1118         }
1119
1120         /**
1121          * Returns true if the title is inside the specified namespace.
1122          *
1123          * Please make use of this instead of comparing to getNamespace()
1124          * This function is much more resistant to changes we may make
1125          * to namespaces than code that makes direct comparisons.
1126          * @param int $ns The namespace
1127          * @return bool
1128          * @since 1.19
1129          */
1130         public function inNamespace( $ns ) {
1131                 return MWNamespace::equals( $this->getNamespace(), $ns );
1132         }
1133
1134         /**
1135          * Returns true if the title is inside one of the specified namespaces.
1136          *
1137          * @param int $namespaces,... The namespaces to check for
1138          * @return bool
1139          * @since 1.19
1140          */
1141         public function inNamespaces( /* ... */ ) {
1142                 $namespaces = func_get_args();
1143                 if ( count( $namespaces ) > 0 && is_array( $namespaces[0] ) ) {
1144                         $namespaces = $namespaces[0];
1145                 }
1146
1147                 foreach ( $namespaces as $ns ) {
1148                         if ( $this->inNamespace( $ns ) ) {
1149                                 return true;
1150                         }
1151                 }
1152
1153                 return false;
1154         }
1155
1156         /**
1157          * Returns true if the title has the same subject namespace as the
1158          * namespace specified.
1159          * For example this method will take NS_USER and return true if namespace
1160          * is either NS_USER or NS_USER_TALK since both of them have NS_USER
1161          * as their subject namespace.
1162          *
1163          * This is MUCH simpler than individually testing for equivalence
1164          * against both NS_USER and NS_USER_TALK, and is also forward compatible.
1165          * @since 1.19
1166          * @param int $ns
1167          * @return bool
1168          */
1169         public function hasSubjectNamespace( $ns ) {
1170                 return MWNamespace::subjectEquals( $this->getNamespace(), $ns );
1171         }
1172
1173         /**
1174          * Is this Title in a namespace which contains content?
1175          * In other words, is this a content page, for the purposes of calculating
1176          * statistics, etc?
1177          *
1178          * @return bool
1179          */
1180         public function isContentPage() {
1181                 return MWNamespace::isContent( $this->getNamespace() );
1182         }
1183
1184         /**
1185          * Would anybody with sufficient privileges be able to move this page?
1186          * Some pages just aren't movable.
1187          *
1188          * @return bool
1189          */
1190         public function isMovable() {
1191                 if ( !MWNamespace::isMovable( $this->getNamespace() ) || $this->isExternal() ) {
1192                         // Interwiki title or immovable namespace. Hooks don't get to override here
1193                         return false;
1194                 }
1195
1196                 $result = true;
1197                 Hooks::run( 'TitleIsMovable', array( $this, &$result ) );
1198                 return $result;
1199         }
1200
1201         /**
1202          * Is this the mainpage?
1203          * @note Title::newFromText seems to be sufficiently optimized by the title
1204          * cache that we don't need to over-optimize by doing direct comparisons and
1205          * accidentally creating new bugs where $title->equals( Title::newFromText() )
1206          * ends up reporting something differently than $title->isMainPage();
1207          *
1208          * @since 1.18
1209          * @return bool
1210          */
1211         public function isMainPage() {
1212                 return $this->equals( Title::newMainPage() );
1213         }
1214
1215         /**
1216          * Is this a subpage?
1217          *
1218          * @return bool
1219          */
1220         public function isSubpage() {
1221                 return MWNamespace::hasSubpages( $this->mNamespace )
1222                         ? strpos( $this->getText(), '/' ) !== false
1223                         : false;
1224         }
1225
1226         /**
1227          * Is this a conversion table for the LanguageConverter?
1228          *
1229          * @return bool
1230          */
1231         public function isConversionTable() {
1232                 // @todo ConversionTable should become a separate content model.
1233
1234                 return $this->getNamespace() == NS_MEDIAWIKI &&
1235                         strpos( $this->getText(), 'Conversiontable/' ) === 0;
1236         }
1237
1238         /**
1239          * Does that page contain wikitext, or it is JS, CSS or whatever?
1240          *
1241          * @return bool
1242          */
1243         public function isWikitextPage() {
1244                 return $this->hasContentModel( CONTENT_MODEL_WIKITEXT );
1245         }
1246
1247         /**
1248          * Could this page contain custom CSS or JavaScript for the global UI.
1249          * This is generally true for pages in the MediaWiki namespace having CONTENT_MODEL_CSS
1250          * or CONTENT_MODEL_JAVASCRIPT.
1251          *
1252          * This method does *not* return true for per-user JS/CSS. Use isCssJsSubpage()
1253          * for that!
1254          *
1255          * Note that this method should not return true for pages that contain and
1256          * show "inactive" CSS or JS.
1257          *
1258          * @return bool
1259          */
1260         public function isCssOrJsPage() {
1261                 $isCssOrJsPage = NS_MEDIAWIKI == $this->mNamespace
1262                         && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1263                                 || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1264
1265                 # @note This hook is also called in ContentHandler::getDefaultModel.
1266                 #   It's called here again to make sure hook functions can force this
1267                 #   method to return true even outside the MediaWiki namespace.
1268
1269                 Hooks::run( 'TitleIsCssOrJsPage', array( $this, &$isCssOrJsPage ), '1.25' );
1270
1271                 return $isCssOrJsPage;
1272         }
1273
1274         /**
1275          * Is this a .css or .js subpage of a user page?
1276          * @return bool
1277          */
1278         public function isCssJsSubpage() {
1279                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1280                                 && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1281                                         || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) ) );
1282         }
1283
1284         /**
1285          * Trim down a .css or .js subpage title to get the corresponding skin name
1286          *
1287          * @return string Containing skin name from .css or .js subpage title
1288          */
1289         public function getSkinFromCssJsSubpage() {
1290                 $subpage = explode( '/', $this->mTextform );
1291                 $subpage = $subpage[count( $subpage ) - 1];
1292                 $lastdot = strrpos( $subpage, '.' );
1293                 if ( $lastdot === false ) {
1294                         return $subpage; # Never happens: only called for names ending in '.css' or '.js'
1295                 }
1296                 return substr( $subpage, 0, $lastdot );
1297         }
1298
1299         /**
1300          * Is this a .css subpage of a user page?
1301          *
1302          * @return bool
1303          */
1304         public function isCssSubpage() {
1305                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1306                         && $this->hasContentModel( CONTENT_MODEL_CSS ) );
1307         }
1308
1309         /**
1310          * Is this a .js subpage of a user page?
1311          *
1312          * @return bool
1313          */
1314         public function isJsSubpage() {
1315                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1316                         && $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1317         }
1318
1319         /**
1320          * Is this a talk page of some sort?
1321          *
1322          * @return bool
1323          */
1324         public function isTalkPage() {
1325                 return MWNamespace::isTalk( $this->getNamespace() );
1326         }
1327
1328         /**
1329          * Get a Title object associated with the talk page of this article
1330          *
1331          * @return Title The object for the talk page
1332          */
1333         public function getTalkPage() {
1334                 return Title::makeTitle( MWNamespace::getTalk( $this->getNamespace() ), $this->getDBkey() );
1335         }
1336
1337         /**
1338          * Get a title object associated with the subject page of this
1339          * talk page
1340          *
1341          * @return Title The object for the subject page
1342          */
1343         public function getSubjectPage() {
1344                 // Is this the same title?
1345                 $subjectNS = MWNamespace::getSubject( $this->getNamespace() );
1346                 if ( $this->getNamespace() == $subjectNS ) {
1347                         return $this;
1348                 }
1349                 return Title::makeTitle( $subjectNS, $this->getDBkey() );
1350         }
1351
1352         /**
1353          * Get the other title for this page, if this is a subject page
1354          * get the talk page, if it is a subject page get the talk page
1355          *
1356          * @since 1.25
1357          * @throws MWException
1358          * @return Title
1359          */
1360         public function getOtherPage() {
1361                 if ( $this->isSpecialPage() ) {
1362                         throw new MWException( 'Special pages cannot have other pages' );
1363                 }
1364                 if ( $this->isTalkPage() ) {
1365                         return $this->getSubjectPage();
1366                 } else {
1367                         return $this->getTalkPage();
1368                 }
1369         }
1370
1371         /**
1372          * Get the default namespace index, for when there is no namespace
1373          *
1374          * @return int Default namespace index
1375          */
1376         public function getDefaultNamespace() {
1377                 return $this->mDefaultNamespace;
1378         }
1379
1380         /**
1381          * Get the Title fragment (i.e.\ the bit after the #) in text form
1382          *
1383          * Use Title::hasFragment to check for a fragment
1384          *
1385          * @return string Title fragment
1386          */
1387         public function getFragment() {
1388                 return $this->mFragment;
1389         }
1390
1391         /**
1392          * Check if a Title fragment is set
1393          *
1394          * @return bool
1395          * @since 1.23
1396          */
1397         public function hasFragment() {
1398                 return $this->mFragment !== '';
1399         }
1400
1401         /**
1402          * Get the fragment in URL form, including the "#" character if there is one
1403          * @return string Fragment in URL form
1404          */
1405         public function getFragmentForURL() {
1406                 if ( !$this->hasFragment() ) {
1407                         return '';
1408                 } else {
1409                         return '#' . Title::escapeFragmentForURL( $this->getFragment() );
1410                 }
1411         }
1412
1413         /**
1414          * Set the fragment for this title. Removes the first character from the
1415          * specified fragment before setting, so it assumes you're passing it with
1416          * an initial "#".
1417          *
1418          * Deprecated for public use, use Title::makeTitle() with fragment parameter.
1419          * Still in active use privately.
1420          *
1421          * @private
1422          * @param string $fragment Text
1423          */
1424         public function setFragment( $fragment ) {
1425                 $this->mFragment = strtr( substr( $fragment, 1 ), '_', ' ' );
1426         }
1427
1428         /**
1429          * Prefix some arbitrary text with the namespace or interwiki prefix
1430          * of this object
1431          *
1432          * @param string $name The text
1433          * @return string The prefixed text
1434          */
1435         private function prefix( $name ) {
1436                 $p = '';
1437                 if ( $this->isExternal() ) {
1438                         $p = $this->mInterwiki . ':';
1439                 }
1440
1441                 if ( 0 != $this->mNamespace ) {
1442                         $p .= $this->getNsText() . ':';
1443                 }
1444                 return $p . $name;
1445         }
1446
1447         /**
1448          * Get the prefixed database key form
1449          *
1450          * @return string The prefixed title, with underscores and
1451          *  any interwiki and namespace prefixes
1452          */
1453         public function getPrefixedDBkey() {
1454                 $s = $this->prefix( $this->mDbkeyform );
1455                 $s = strtr( $s, ' ', '_' );
1456                 return $s;
1457         }
1458
1459         /**
1460          * Get the prefixed title with spaces.
1461          * This is the form usually used for display
1462          *
1463          * @return string The prefixed title, with spaces
1464          */
1465         public function getPrefixedText() {
1466                 if ( $this->mPrefixedText === null ) {
1467                         $s = $this->prefix( $this->mTextform );
1468                         $s = strtr( $s, '_', ' ' );
1469                         $this->mPrefixedText = $s;
1470                 }
1471                 return $this->mPrefixedText;
1472         }
1473
1474         /**
1475          * Return a string representation of this title
1476          *
1477          * @return string Representation of this title
1478          */
1479         public function __toString() {
1480                 return $this->getPrefixedText();
1481         }
1482
1483         /**
1484          * Get the prefixed title with spaces, plus any fragment
1485          * (part beginning with '#')
1486          *
1487          * @return string The prefixed title, with spaces and the fragment, including '#'
1488          */
1489         public function getFullText() {
1490                 $text = $this->getPrefixedText();
1491                 if ( $this->hasFragment() ) {
1492                         $text .= '#' . $this->getFragment();
1493                 }
1494                 return $text;
1495         }
1496
1497         /**
1498          * Get the root page name text without a namespace, i.e. the leftmost part before any slashes
1499          *
1500          * @par Example:
1501          * @code
1502          * Title::newFromText('User:Foo/Bar/Baz')->getRootText();
1503          * # returns: 'Foo'
1504          * @endcode
1505          *
1506          * @return string Root name
1507          * @since 1.20
1508          */
1509         public function getRootText() {
1510                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1511                         return $this->getText();
1512                 }
1513
1514                 return strtok( $this->getText(), '/' );
1515         }
1516
1517         /**
1518          * Get the root page name title, i.e. the leftmost part before any slashes
1519          *
1520          * @par Example:
1521          * @code
1522          * Title::newFromText('User:Foo/Bar/Baz')->getRootTitle();
1523          * # returns: Title{User:Foo}
1524          * @endcode
1525          *
1526          * @return Title Root title
1527          * @since 1.20
1528          */
1529         public function getRootTitle() {
1530                 return Title::makeTitle( $this->getNamespace(), $this->getRootText() );
1531         }
1532
1533         /**
1534          * Get the base page name without a namespace, i.e. the part before the subpage name
1535          *
1536          * @par Example:
1537          * @code
1538          * Title::newFromText('User:Foo/Bar/Baz')->getBaseText();
1539          * # returns: 'Foo/Bar'
1540          * @endcode
1541          *
1542          * @return string Base name
1543          */
1544         public function getBaseText() {
1545                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1546                         return $this->getText();
1547                 }
1548
1549                 $parts = explode( '/', $this->getText() );
1550                 # Don't discard the real title if there's no subpage involved
1551                 if ( count( $parts ) > 1 ) {
1552                         unset( $parts[count( $parts ) - 1] );
1553                 }
1554                 return implode( '/', $parts );
1555         }
1556
1557         /**
1558          * Get the base page name title, i.e. the part before the subpage name
1559          *
1560          * @par Example:
1561          * @code
1562          * Title::newFromText('User:Foo/Bar/Baz')->getBaseTitle();
1563          * # returns: Title{User:Foo/Bar}
1564          * @endcode
1565          *
1566          * @return Title Base title
1567          * @since 1.20
1568          */
1569         public function getBaseTitle() {
1570                 return Title::makeTitle( $this->getNamespace(), $this->getBaseText() );
1571         }
1572
1573         /**
1574          * Get the lowest-level subpage name, i.e. the rightmost part after any slashes
1575          *
1576          * @par Example:
1577          * @code
1578          * Title::newFromText('User:Foo/Bar/Baz')->getSubpageText();
1579          * # returns: "Baz"
1580          * @endcode
1581          *
1582          * @return string Subpage name
1583          */
1584         public function getSubpageText() {
1585                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1586                         return $this->mTextform;
1587                 }
1588                 $parts = explode( '/', $this->mTextform );
1589                 return $parts[count( $parts ) - 1];
1590         }
1591
1592         /**
1593          * Get the title for a subpage of the current page
1594          *
1595          * @par Example:
1596          * @code
1597          * Title::newFromText('User:Foo/Bar/Baz')->getSubpage("Asdf");
1598          * # returns: Title{User:Foo/Bar/Baz/Asdf}
1599          * @endcode
1600          *
1601          * @param string $text The subpage name to add to the title
1602          * @return Title Subpage title
1603          * @since 1.20
1604          */
1605         public function getSubpage( $text ) {
1606                 return Title::makeTitleSafe( $this->getNamespace(), $this->getText() . '/' . $text );
1607         }
1608
1609         /**
1610          * Get a URL-encoded form of the subpage text
1611          *
1612          * @return string URL-encoded subpage name
1613          */
1614         public function getSubpageUrlForm() {
1615                 $text = $this->getSubpageText();
1616                 $text = wfUrlencode( strtr( $text, ' ', '_' ) );
1617                 return $text;
1618         }
1619
1620         /**
1621          * Get a URL-encoded title (not an actual URL) including interwiki
1622          *
1623          * @return string The URL-encoded form
1624          */
1625         public function getPrefixedURL() {
1626                 $s = $this->prefix( $this->mDbkeyform );
1627                 $s = wfUrlencode( strtr( $s, ' ', '_' ) );
1628                 return $s;
1629         }
1630
1631         /**
1632          * Helper to fix up the get{Canonical,Full,Link,Local,Internal}URL args
1633          * get{Canonical,Full,Link,Local,Internal}URL methods accepted an optional
1634          * second argument named variant. This was deprecated in favor
1635          * of passing an array of option with a "variant" key
1636          * Once $query2 is removed for good, this helper can be dropped
1637          * and the wfArrayToCgi moved to getLocalURL();
1638          *
1639          * @since 1.19 (r105919)
1640          * @param array|string $query
1641          * @param bool $query2
1642          * @return string
1643          */
1644         private static function fixUrlQueryArgs( $query, $query2 = false ) {
1645                 if ( $query2 !== false ) {
1646                         wfDeprecated( "Title::get{Canonical,Full,Link,Local,Internal}URL " .
1647                                 "method called with a second parameter is deprecated. Add your " .
1648                                 "parameter to an array passed as the first parameter.", "1.19" );
1649                 }
1650                 if ( is_array( $query ) ) {
1651                         $query = wfArrayToCgi( $query );
1652                 }
1653                 if ( $query2 ) {
1654                         if ( is_string( $query2 ) ) {
1655                                 // $query2 is a string, we will consider this to be
1656                                 // a deprecated $variant argument and add it to the query
1657                                 $query2 = wfArrayToCgi( array( 'variant' => $query2 ) );
1658                         } else {
1659                                 $query2 = wfArrayToCgi( $query2 );
1660                         }
1661                         // If we have $query content add a & to it first
1662                         if ( $query ) {
1663                                 $query .= '&';
1664                         }
1665                         // Now append the queries together
1666                         $query .= $query2;
1667                 }
1668                 return $query;
1669         }
1670
1671         /**
1672          * Get a real URL referring to this title, with interwiki link and
1673          * fragment
1674          *
1675          * @see self::getLocalURL for the arguments.
1676          * @see wfExpandUrl
1677          * @param array|string $query
1678          * @param bool $query2
1679          * @param string $proto Protocol type to use in URL
1680          * @return string The URL
1681          */
1682         public function getFullURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1683                 $query = self::fixUrlQueryArgs( $query, $query2 );
1684
1685                 # Hand off all the decisions on urls to getLocalURL
1686                 $url = $this->getLocalURL( $query );
1687
1688                 # Expand the url to make it a full url. Note that getLocalURL has the
1689                 # potential to output full urls for a variety of reasons, so we use
1690                 # wfExpandUrl instead of simply prepending $wgServer
1691                 $url = wfExpandUrl( $url, $proto );
1692
1693                 # Finally, add the fragment.
1694                 $url .= $this->getFragmentForURL();
1695
1696                 Hooks::run( 'GetFullURL', array( &$this, &$url, $query ) );
1697                 return $url;
1698         }
1699
1700         /**
1701          * Get a URL with no fragment or server name (relative URL) from a Title object.
1702          * If this page is generated with action=render, however,
1703          * $wgServer is prepended to make an absolute URL.
1704          *
1705          * @see self::getFullURL to always get an absolute URL.
1706          * @see self::getLinkURL to always get a URL that's the simplest URL that will be
1707          *  valid to link, locally, to the current Title.
1708          * @see self::newFromText to produce a Title object.
1709          *
1710          * @param string|array $query An optional query string,
1711          *   not used for interwiki links. Can be specified as an associative array as well,
1712          *   e.g., array( 'action' => 'edit' ) (keys and values will be URL-escaped).
1713          *   Some query patterns will trigger various shorturl path replacements.
1714          * @param array $query2 An optional secondary query array. This one MUST
1715          *   be an array. If a string is passed it will be interpreted as a deprecated
1716          *   variant argument and urlencoded into a variant= argument.
1717          *   This second query argument will be added to the $query
1718          *   The second parameter is deprecated since 1.19. Pass it as a key,value
1719          *   pair in the first parameter array instead.
1720          *
1721          * @return string String of the URL.
1722          */
1723         public function getLocalURL( $query = '', $query2 = false ) {
1724                 global $wgArticlePath, $wgScript, $wgServer, $wgRequest;
1725
1726                 $query = self::fixUrlQueryArgs( $query, $query2 );
1727
1728                 $interwiki = Interwiki::fetch( $this->mInterwiki );
1729                 if ( $interwiki ) {
1730                         $namespace = $this->getNsText();
1731                         if ( $namespace != '' ) {
1732                                 # Can this actually happen? Interwikis shouldn't be parsed.
1733                                 # Yes! It can in interwiki transclusion. But... it probably shouldn't.
1734                                 $namespace .= ':';
1735                         }
1736                         $url = $interwiki->getURL( $namespace . $this->getDBkey() );
1737                         $url = wfAppendQuery( $url, $query );
1738                 } else {
1739                         $dbkey = wfUrlencode( $this->getPrefixedDBkey() );
1740                         if ( $query == '' ) {
1741                                 $url = str_replace( '$1', $dbkey, $wgArticlePath );
1742                                 Hooks::run( 'GetLocalURL::Article', array( &$this, &$url ) );
1743                         } else {
1744                                 global $wgVariantArticlePath, $wgActionPaths, $wgContLang;
1745                                 $url = false;
1746                                 $matches = array();
1747
1748                                 if ( !empty( $wgActionPaths )
1749                                         && preg_match( '/^(.*&|)action=([^&]*)(&(.*)|)$/', $query, $matches )
1750                                 ) {
1751                                         $action = urldecode( $matches[2] );
1752                                         if ( isset( $wgActionPaths[$action] ) ) {
1753                                                 $query = $matches[1];
1754                                                 if ( isset( $matches[4] ) ) {
1755                                                         $query .= $matches[4];
1756                                                 }
1757                                                 $url = str_replace( '$1', $dbkey, $wgActionPaths[$action] );
1758                                                 if ( $query != '' ) {
1759                                                         $url = wfAppendQuery( $url, $query );
1760                                                 }
1761                                         }
1762                                 }
1763
1764                                 if ( $url === false
1765                                         && $wgVariantArticlePath
1766                                         && $wgContLang->getCode() === $this->getPageLanguage()->getCode()
1767                                         && $this->getPageLanguage()->hasVariants()
1768                                         && preg_match( '/^variant=([^&]*)$/', $query, $matches )
1769                                 ) {
1770                                         $variant = urldecode( $matches[1] );
1771                                         if ( $this->getPageLanguage()->hasVariant( $variant ) ) {
1772                                                 // Only do the variant replacement if the given variant is a valid
1773                                                 // variant for the page's language.
1774                                                 $url = str_replace( '$2', urlencode( $variant ), $wgVariantArticlePath );
1775                                                 $url = str_replace( '$1', $dbkey, $url );
1776                                         }
1777                                 }
1778
1779                                 if ( $url === false ) {
1780                                         if ( $query == '-' ) {
1781                                                 $query = '';
1782                                         }
1783                                         $url = "{$wgScript}?title={$dbkey}&{$query}";
1784                                 }
1785                         }
1786
1787                         Hooks::run( 'GetLocalURL::Internal', array( &$this, &$url, $query ) );
1788
1789                         // @todo FIXME: This causes breakage in various places when we
1790                         // actually expected a local URL and end up with dupe prefixes.
1791                         if ( $wgRequest->getVal( 'action' ) == 'render' ) {
1792                                 $url = $wgServer . $url;
1793                         }
1794                 }
1795                 Hooks::run( 'GetLocalURL', array( &$this, &$url, $query ) );
1796                 return $url;
1797         }
1798
1799         /**
1800          * Get a URL that's the simplest URL that will be valid to link, locally,
1801          * to the current Title.  It includes the fragment, but does not include
1802          * the server unless action=render is used (or the link is external).  If
1803          * there's a fragment but the prefixed text is empty, we just return a link
1804          * to the fragment.
1805          *
1806          * The result obviously should not be URL-escaped, but does need to be
1807          * HTML-escaped if it's being output in HTML.
1808          *
1809          * @param array $query
1810          * @param bool $query2
1811          * @param string $proto Protocol to use; setting this will cause a full URL to be used
1812          * @see self::getLocalURL for the arguments.
1813          * @return string The URL
1814          */
1815         public function getLinkURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1816                 if ( $this->isExternal() || $proto !== PROTO_RELATIVE ) {
1817                         $ret = $this->getFullURL( $query, $query2, $proto );
1818                 } elseif ( $this->getPrefixedText() === '' && $this->hasFragment() ) {
1819                         $ret = $this->getFragmentForURL();
1820                 } else {
1821                         $ret = $this->getLocalURL( $query, $query2 ) . $this->getFragmentForURL();
1822                 }
1823                 return $ret;
1824         }
1825
1826         /**
1827          * Get the URL form for an internal link.
1828          * - Used in various Squid-related code, in case we have a different
1829          * internal hostname for the server from the exposed one.
1830          *
1831          * This uses $wgInternalServer to qualify the path, or $wgServer
1832          * if $wgInternalServer is not set. If the server variable used is
1833          * protocol-relative, the URL will be expanded to http://
1834          *
1835          * @see self::getLocalURL for the arguments.
1836          * @return string The URL
1837          */
1838         public function getInternalURL( $query = '', $query2 = false ) {
1839                 global $wgInternalServer, $wgServer;
1840                 $query = self::fixUrlQueryArgs( $query, $query2 );
1841                 $server = $wgInternalServer !== false ? $wgInternalServer : $wgServer;
1842                 $url = wfExpandUrl( $server . $this->getLocalURL( $query ), PROTO_HTTP );
1843                 Hooks::run( 'GetInternalURL', array( &$this, &$url, $query ) );
1844                 return $url;
1845         }
1846
1847         /**
1848          * Get the URL for a canonical link, for use in things like IRC and
1849          * e-mail notifications. Uses $wgCanonicalServer and the
1850          * GetCanonicalURL hook.
1851          *
1852          * NOTE: Unlike getInternalURL(), the canonical URL includes the fragment
1853          *
1854          * @see self::getLocalURL for the arguments.
1855          * @return string The URL
1856          * @since 1.18
1857          */
1858         public function getCanonicalURL( $query = '', $query2 = false ) {
1859                 $query = self::fixUrlQueryArgs( $query, $query2 );
1860                 $url = wfExpandUrl( $this->getLocalURL( $query ) . $this->getFragmentForURL(), PROTO_CANONICAL );
1861                 Hooks::run( 'GetCanonicalURL', array( &$this, &$url, $query ) );
1862                 return $url;
1863         }
1864
1865         /**
1866          * Get the edit URL for this Title
1867          *
1868          * @return string The URL, or a null string if this is an interwiki link
1869          */
1870         public function getEditURL() {
1871                 if ( $this->isExternal() ) {
1872                         return '';
1873                 }
1874                 $s = $this->getLocalURL( 'action=edit' );
1875
1876                 return $s;
1877         }
1878
1879         /**
1880          * Is $wgUser watching this page?
1881          *
1882          * @deprecated since 1.20; use User::isWatched() instead.
1883          * @return bool
1884          */
1885         public function userIsWatching() {
1886                 global $wgUser;
1887
1888                 if ( is_null( $this->mWatched ) ) {
1889                         if ( NS_SPECIAL == $this->mNamespace || !$wgUser->isLoggedIn() ) {
1890                                 $this->mWatched = false;
1891                         } else {
1892                                 $this->mWatched = $wgUser->isWatched( $this );
1893                         }
1894                 }
1895                 return $this->mWatched;
1896         }
1897
1898         /**
1899          * Can $user perform $action on this page?
1900          * This skips potentially expensive cascading permission checks
1901          * as well as avoids expensive error formatting
1902          *
1903          * Suitable for use for nonessential UI controls in common cases, but
1904          * _not_ for functional access control.
1905          *
1906          * May provide false positives, but should never provide a false negative.
1907          *
1908          * @param string $action Action that permission needs to be checked for
1909          * @param User $user User to check (since 1.19); $wgUser will be used if not provided.
1910          * @return bool
1911          */
1912         public function quickUserCan( $action, $user = null ) {
1913                 return $this->userCan( $action, $user, false );
1914         }
1915
1916         /**
1917          * Can $user perform $action on this page?
1918          *
1919          * @param string $action Action that permission needs to be checked for
1920          * @param User $user User to check (since 1.19); $wgUser will be used if not
1921          *   provided.
1922          * @param string $rigor Same format as Title::getUserPermissionsErrors()
1923          * @return bool
1924          */
1925         public function userCan( $action, $user = null, $rigor = 'secure' ) {
1926                 if ( !$user instanceof User ) {
1927                         global $wgUser;
1928                         $user = $wgUser;
1929                 }
1930
1931                 return !count( $this->getUserPermissionsErrorsInternal( $action, $user, $rigor, true ) );
1932         }
1933
1934         /**
1935          * Can $user perform $action on this page?
1936          *
1937          * @todo FIXME: This *does not* check throttles (User::pingLimiter()).
1938          *
1939          * @param string $action Action that permission needs to be checked for
1940          * @param User $user User to check
1941          * @param string $rigor One of (quick,full,secure)
1942          *   - quick  : does cheap permission checks from slaves (usable for GUI creation)
1943          *   - full   : does cheap and expensive checks possibly from a slave
1944          *   - secure : does cheap and expensive checks, using the master as needed
1945          * @param array $ignoreErrors Array of Strings Set this to a list of message keys
1946          *   whose corresponding errors may be ignored.
1947          * @return array Array of arguments to wfMessage to explain permissions problems.
1948          */
1949         public function getUserPermissionsErrors(
1950                 $action, $user, $rigor = 'secure', $ignoreErrors = array()
1951         ) {
1952                 $errors = $this->getUserPermissionsErrorsInternal( $action, $user, $rigor );
1953
1954                 // Remove the errors being ignored.
1955                 foreach ( $errors as $index => $error ) {
1956                         $error_key = is_array( $error ) ? $error[0] : $error;
1957
1958                         if ( in_array( $error_key, $ignoreErrors ) ) {
1959                                 unset( $errors[$index] );
1960                         }
1961                 }
1962
1963                 return $errors;
1964         }
1965
1966         /**
1967          * Permissions checks that fail most often, and which are easiest to test.
1968          *
1969          * @param string $action The action to check
1970          * @param User $user User to check
1971          * @param array $errors List of current errors
1972          * @param string $rigor Same format as Title::getUserPermissionsErrors()
1973          * @param bool $short Short circuit on first error
1974          *
1975          * @return array List of errors
1976          */
1977         private function checkQuickPermissions( $action, $user, $errors, $rigor, $short ) {
1978                 if ( !Hooks::run( 'TitleQuickPermissions',
1979                         array( $this, $user, $action, &$errors, ( $rigor !== 'quick' ), $short ) )
1980                 ) {
1981                         return $errors;
1982                 }
1983
1984                 if ( $action == 'create' ) {
1985                         if (
1986                                 ( $this->isTalkPage() && !$user->isAllowed( 'createtalk' ) ) ||
1987                                 ( !$this->isTalkPage() && !$user->isAllowed( 'createpage' ) )
1988                         ) {
1989                                 $errors[] = $user->isAnon() ? array( 'nocreatetext' ) : array( 'nocreate-loggedin' );
1990                         }
1991                 } elseif ( $action == 'move' ) {
1992                         if ( !$user->isAllowed( 'move-rootuserpages' )
1993                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
1994                                 // Show user page-specific message only if the user can move other pages
1995                                 $errors[] = array( 'cant-move-user-page' );
1996                         }
1997
1998                         // Check if user is allowed to move files if it's a file
1999                         if ( $this->mNamespace == NS_FILE && !$user->isAllowed( 'movefile' ) ) {
2000                                 $errors[] = array( 'movenotallowedfile' );
2001                         }
2002
2003                         // Check if user is allowed to move category pages if it's a category page
2004                         if ( $this->mNamespace == NS_CATEGORY && !$user->isAllowed( 'move-categorypages' ) ) {
2005                                 $errors[] = array( 'cant-move-category-page' );
2006                         }
2007
2008                         if ( !$user->isAllowed( 'move' ) ) {
2009                                 // User can't move anything
2010                                 $userCanMove = User::groupHasPermission( 'user', 'move' );
2011                                 $autoconfirmedCanMove = User::groupHasPermission( 'autoconfirmed', 'move' );
2012                                 if ( $user->isAnon() && ( $userCanMove || $autoconfirmedCanMove ) ) {
2013                                         // custom message if logged-in users without any special rights can move
2014                                         $errors[] = array( 'movenologintext' );
2015                                 } else {
2016                                         $errors[] = array( 'movenotallowed' );
2017                                 }
2018                         }
2019                 } elseif ( $action == 'move-target' ) {
2020                         if ( !$user->isAllowed( 'move' ) ) {
2021                                 // User can't move anything
2022                                 $errors[] = array( 'movenotallowed' );
2023                         } elseif ( !$user->isAllowed( 'move-rootuserpages' )
2024                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
2025                                 // Show user page-specific message only if the user can move other pages
2026                                 $errors[] = array( 'cant-move-to-user-page' );
2027                         } elseif ( !$user->isAllowed( 'move-categorypages' )
2028                                         && $this->mNamespace == NS_CATEGORY ) {
2029                                 // Show category page-specific message only if the user can move other pages
2030                                 $errors[] = array( 'cant-move-to-category-page' );
2031                         }
2032                 } elseif ( !$user->isAllowed( $action ) ) {
2033                         $errors[] = $this->missingPermissionError( $action, $short );
2034                 }
2035
2036                 return $errors;
2037         }
2038
2039         /**
2040          * Add the resulting error code to the errors array
2041          *
2042          * @param array $errors List of current errors
2043          * @param array $result Result of errors
2044          *
2045          * @return array List of errors
2046          */
2047         private function resultToError( $errors, $result ) {
2048                 if ( is_array( $result ) && count( $result ) && !is_array( $result[0] ) ) {
2049                         // A single array representing an error
2050                         $errors[] = $result;
2051                 } elseif ( is_array( $result ) && is_array( $result[0] ) ) {
2052                         // A nested array representing multiple errors
2053                         $errors = array_merge( $errors, $result );
2054                 } elseif ( $result !== '' && is_string( $result ) ) {
2055                         // A string representing a message-id
2056                         $errors[] = array( $result );
2057                 } elseif ( $result === false ) {
2058                         // a generic "We don't want them to do that"
2059                         $errors[] = array( 'badaccess-group0' );
2060                 }
2061                 return $errors;
2062         }
2063
2064         /**
2065          * Check various permission hooks
2066          *
2067          * @param string $action The action to check
2068          * @param User $user User to check
2069          * @param array $errors List of current errors
2070          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2071          * @param bool $short Short circuit on first error
2072          *
2073          * @return array List of errors
2074          */
2075         private function checkPermissionHooks( $action, $user, $errors, $rigor, $short ) {
2076                 // Use getUserPermissionsErrors instead
2077                 $result = '';
2078                 if ( !Hooks::run( 'userCan', array( &$this, &$user, $action, &$result ) ) ) {
2079                         return $result ? array() : array( array( 'badaccess-group0' ) );
2080                 }
2081                 // Check getUserPermissionsErrors hook
2082                 if ( !Hooks::run( 'getUserPermissionsErrors', array( &$this, &$user, $action, &$result ) ) ) {
2083                         $errors = $this->resultToError( $errors, $result );
2084                 }
2085                 // Check getUserPermissionsErrorsExpensive hook
2086                 if (
2087                         $rigor !== 'quick'
2088                         && !( $short && count( $errors ) > 0 )
2089                         && !Hooks::run( 'getUserPermissionsErrorsExpensive', array( &$this, &$user, $action, &$result ) )
2090                 ) {
2091                         $errors = $this->resultToError( $errors, $result );
2092                 }
2093
2094                 return $errors;
2095         }
2096
2097         /**
2098          * Check permissions on special pages & namespaces
2099          *
2100          * @param string $action The action to check
2101          * @param User $user User to check
2102          * @param array $errors List of current errors
2103          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2104          * @param bool $short Short circuit on first error
2105          *
2106          * @return array List of errors
2107          */
2108         private function checkSpecialsAndNSPermissions( $action, $user, $errors, $rigor, $short ) {
2109                 # Only 'createaccount' can be performed on special pages,
2110                 # which don't actually exist in the DB.
2111                 if ( NS_SPECIAL == $this->mNamespace && $action !== 'createaccount' ) {
2112                         $errors[] = array( 'ns-specialprotected' );
2113                 }
2114
2115                 # Check $wgNamespaceProtection for restricted namespaces
2116                 if ( $this->isNamespaceProtected( $user ) ) {
2117                         $ns = $this->mNamespace == NS_MAIN ?
2118                                 wfMessage( 'nstab-main' )->text() : $this->getNsText();
2119                         $errors[] = $this->mNamespace == NS_MEDIAWIKI ?
2120                                 array( 'protectedinterface', $action ) : array( 'namespaceprotected', $ns, $action );
2121                 }
2122
2123                 return $errors;
2124         }
2125
2126         /**
2127          * Check CSS/JS sub-page permissions
2128          *
2129          * @param string $action The action to check
2130          * @param User $user User to check
2131          * @param array $errors List of current errors
2132          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2133          * @param bool $short Short circuit on first error
2134          *
2135          * @return array List of errors
2136          */
2137         private function checkCSSandJSPermissions( $action, $user, $errors, $rigor, $short ) {
2138                 # Protect css/js subpages of user pages
2139                 # XXX: this might be better using restrictions
2140                 # XXX: right 'editusercssjs' is deprecated, for backward compatibility only
2141                 if ( $action != 'patrol' && !$user->isAllowed( 'editusercssjs' ) ) {
2142                         if ( preg_match( '/^' . preg_quote( $user->getName(), '/' ) . '\//', $this->mTextform ) ) {
2143                                 if ( $this->isCssSubpage() && !$user->isAllowedAny( 'editmyusercss', 'editusercss' ) ) {
2144                                         $errors[] = array( 'mycustomcssprotected', $action );
2145                                 } elseif ( $this->isJsSubpage() && !$user->isAllowedAny( 'editmyuserjs', 'edituserjs' ) ) {
2146                                         $errors[] = array( 'mycustomjsprotected', $action );
2147                                 }
2148                         } else {
2149                                 if ( $this->isCssSubpage() && !$user->isAllowed( 'editusercss' ) ) {
2150                                         $errors[] = array( 'customcssprotected', $action );
2151                                 } elseif ( $this->isJsSubpage() && !$user->isAllowed( 'edituserjs' ) ) {
2152                                         $errors[] = array( 'customjsprotected', $action );
2153                                 }
2154                         }
2155                 }
2156
2157                 return $errors;
2158         }
2159
2160         /**
2161          * Check against page_restrictions table requirements on this
2162          * page. The user must possess all required rights for this
2163          * action.
2164          *
2165          * @param string $action The action to check
2166          * @param User $user User to check
2167          * @param array $errors List of current errors
2168          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2169          * @param bool $short Short circuit on first error
2170          *
2171          * @return array List of errors
2172          */
2173         private function checkPageRestrictions( $action, $user, $errors, $rigor, $short ) {
2174                 foreach ( $this->getRestrictions( $action ) as $right ) {
2175                         // Backwards compatibility, rewrite sysop -> editprotected
2176                         if ( $right == 'sysop' ) {
2177                                 $right = 'editprotected';
2178                         }
2179                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2180                         if ( $right == 'autoconfirmed' ) {
2181                                 $right = 'editsemiprotected';
2182                         }
2183                         if ( $right == '' ) {
2184                                 continue;
2185                         }
2186                         if ( !$user->isAllowed( $right ) ) {
2187                                 $errors[] = array( 'protectedpagetext', $right, $action );
2188                         } elseif ( $this->mCascadeRestriction && !$user->isAllowed( 'protect' ) ) {
2189                                 $errors[] = array( 'protectedpagetext', 'protect', $action );
2190                         }
2191                 }
2192
2193                 return $errors;
2194         }
2195
2196         /**
2197          * Check restrictions on cascading pages.
2198          *
2199          * @param string $action The action to check
2200          * @param User $user User to check
2201          * @param array $errors List of current errors
2202          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2203          * @param bool $short Short circuit on first error
2204          *
2205          * @return array List of errors
2206          */
2207         private function checkCascadingSourcesRestrictions( $action, $user, $errors, $rigor, $short ) {
2208                 if ( $rigor !== 'quick' && !$this->isCssJsSubpage() ) {
2209                         # We /could/ use the protection level on the source page, but it's
2210                         # fairly ugly as we have to establish a precedence hierarchy for pages
2211                         # included by multiple cascade-protected pages. So just restrict
2212                         # it to people with 'protect' permission, as they could remove the
2213                         # protection anyway.
2214                         list( $cascadingSources, $restrictions ) = $this->getCascadeProtectionSources();
2215                         # Cascading protection depends on more than this page...
2216                         # Several cascading protected pages may include this page...
2217                         # Check each cascading level
2218                         # This is only for protection restrictions, not for all actions
2219                         if ( isset( $restrictions[$action] ) ) {
2220                                 foreach ( $restrictions[$action] as $right ) {
2221                                         // Backwards compatibility, rewrite sysop -> editprotected
2222                                         if ( $right == 'sysop' ) {
2223                                                 $right = 'editprotected';
2224                                         }
2225                                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2226                                         if ( $right == 'autoconfirmed' ) {
2227                                                 $right = 'editsemiprotected';
2228                                         }
2229                                         if ( $right != '' && !$user->isAllowedAll( 'protect', $right ) ) {
2230                                                 $pages = '';
2231                                                 foreach ( $cascadingSources as $page ) {
2232                                                         $pages .= '* [[:' . $page->getPrefixedText() . "]]\n";
2233                                                 }
2234                                                 $errors[] = array( 'cascadeprotected', count( $cascadingSources ), $pages, $action );
2235                                         }
2236                                 }
2237                         }
2238                 }
2239
2240                 return $errors;
2241         }
2242
2243         /**
2244          * Check action permissions not already checked in checkQuickPermissions
2245          *
2246          * @param string $action The action to check
2247          * @param User $user User to check
2248          * @param array $errors List of current errors
2249          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2250          * @param bool $short Short circuit on first error
2251          *
2252          * @return array List of errors
2253          */
2254         private function checkActionPermissions( $action, $user, $errors, $rigor, $short ) {
2255                 global $wgDeleteRevisionsLimit, $wgLang;
2256
2257                 if ( $action == 'protect' ) {
2258                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit', $user, $rigor, true ) ) ) {
2259                                 // If they can't edit, they shouldn't protect.
2260                                 $errors[] = array( 'protect-cantedit' );
2261                         }
2262                 } elseif ( $action == 'create' ) {
2263                         $title_protection = $this->getTitleProtection();
2264                         if ( $title_protection ) {
2265                                 if ( $title_protection['permission'] == ''
2266                                         || !$user->isAllowed( $title_protection['permission'] )
2267                                 ) {
2268                                         $errors[] = array(
2269                                                 'titleprotected',
2270                                                 User::whoIs( $title_protection['user'] ),
2271                                                 $title_protection['reason']
2272                                         );
2273                                 }
2274                         }
2275                 } elseif ( $action == 'move' ) {
2276                         // Check for immobile pages
2277                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2278                                 // Specific message for this case
2279                                 $errors[] = array( 'immobile-source-namespace', $this->getNsText() );
2280                         } elseif ( !$this->isMovable() ) {
2281                                 // Less specific message for rarer cases
2282                                 $errors[] = array( 'immobile-source-page' );
2283                         }
2284                 } elseif ( $action == 'move-target' ) {
2285                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2286                                 $errors[] = array( 'immobile-target-namespace', $this->getNsText() );
2287                         } elseif ( !$this->isMovable() ) {
2288                                 $errors[] = array( 'immobile-target-page' );
2289                         }
2290                 } elseif ( $action == 'delete' ) {
2291                         $tempErrors = $this->checkPageRestrictions( 'edit', $user, array(), $rigor, true );
2292                         if ( !$tempErrors ) {
2293                                 $tempErrors = $this->checkCascadingSourcesRestrictions( 'edit',
2294                                         $user, $tempErrors, $rigor, true );
2295                         }
2296                         if ( $tempErrors ) {
2297                                 // If protection keeps them from editing, they shouldn't be able to delete.
2298                                 $errors[] = array( 'deleteprotected' );
2299                         }
2300                         if ( $rigor !== 'quick' && $wgDeleteRevisionsLimit
2301                                 && !$this->userCan( 'bigdelete', $user ) && $this->isBigDeletion()
2302                         ) {
2303                                 $errors[] = array( 'delete-toobig', $wgLang->formatNum( $wgDeleteRevisionsLimit ) );
2304                         }
2305                 }
2306                 return $errors;
2307         }
2308
2309         /**
2310          * Check that the user isn't blocked from editing.
2311          *
2312          * @param string $action The action to check
2313          * @param User $user User to check
2314          * @param array $errors List of current errors
2315          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2316          * @param bool $short Short circuit on first error
2317          *
2318          * @return array List of errors
2319          */
2320         private function checkUserBlock( $action, $user, $errors, $rigor, $short ) {
2321                 // Account creation blocks handled at userlogin.
2322                 // Unblocking handled in SpecialUnblock
2323                 if ( $rigor === 'quick' || in_array( $action, array( 'createaccount', 'unblock' ) ) ) {
2324                         return $errors;
2325                 }
2326
2327                 global $wgEmailConfirmToEdit;
2328
2329                 if ( $wgEmailConfirmToEdit && !$user->isEmailConfirmed() ) {
2330                         $errors[] = array( 'confirmedittext' );
2331                 }
2332
2333                 $useSlave = ( $rigor !== 'secure' );
2334                 if ( ( $action == 'edit' || $action == 'create' )
2335                         && !$user->isBlockedFrom( $this, $useSlave )
2336                 ) {
2337                         // Don't block the user from editing their own talk page unless they've been
2338                         // explicitly blocked from that too.
2339                 } elseif ( $user->isBlocked() && $user->getBlock()->prevents( $action ) !== false ) {
2340                         // @todo FIXME: Pass the relevant context into this function.
2341                         $errors[] = $user->getBlock()->getPermissionsError( RequestContext::getMain() );
2342                 }
2343
2344                 return $errors;
2345         }
2346
2347         /**
2348          * Check that the user is allowed to read this page.
2349          *
2350          * @param string $action The action to check
2351          * @param User $user User to check
2352          * @param array $errors List of current errors
2353          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2354          * @param bool $short Short circuit on first error
2355          *
2356          * @return array List of errors
2357          */
2358         private function checkReadPermissions( $action, $user, $errors, $rigor, $short ) {
2359                 global $wgWhitelistRead, $wgWhitelistReadRegexp;
2360
2361                 $whitelisted = false;
2362                 if ( User::isEveryoneAllowed( 'read' ) ) {
2363                         # Shortcut for public wikis, allows skipping quite a bit of code
2364                         $whitelisted = true;
2365                 } elseif ( $user->isAllowed( 'read' ) ) {
2366                         # If the user is allowed to read pages, he is allowed to read all pages
2367                         $whitelisted = true;
2368                 } elseif ( $this->isSpecial( 'Userlogin' )
2369                         || $this->isSpecial( 'ChangePassword' )
2370                         || $this->isSpecial( 'PasswordReset' )
2371                 ) {
2372                         # Always grant access to the login page.
2373                         # Even anons need to be able to log in.
2374                         $whitelisted = true;
2375                 } elseif ( is_array( $wgWhitelistRead ) && count( $wgWhitelistRead ) ) {
2376                         # Time to check the whitelist
2377                         # Only do these checks is there's something to check against
2378                         $name = $this->getPrefixedText();
2379                         $dbName = $this->getPrefixedDBkey();
2380
2381                         // Check for explicit whitelisting with and without underscores
2382                         if ( in_array( $name, $wgWhitelistRead, true ) || in_array( $dbName, $wgWhitelistRead, true ) ) {
2383                                 $whitelisted = true;
2384                         } elseif ( $this->getNamespace() == NS_MAIN ) {
2385                                 # Old settings might have the title prefixed with
2386                                 # a colon for main-namespace pages
2387                                 if ( in_array( ':' . $name, $wgWhitelistRead ) ) {
2388                                         $whitelisted = true;
2389                                 }
2390                         } elseif ( $this->isSpecialPage() ) {
2391                                 # If it's a special page, ditch the subpage bit and check again
2392                                 $name = $this->getDBkey();
2393                                 list( $name, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $name );
2394                                 if ( $name ) {
2395                                         $pure = SpecialPage::getTitleFor( $name )->getPrefixedText();
2396                                         if ( in_array( $pure, $wgWhitelistRead, true ) ) {
2397                                                 $whitelisted = true;
2398                                         }
2399                                 }
2400                         }
2401                 }
2402
2403                 if ( !$whitelisted && is_array( $wgWhitelistReadRegexp ) && !empty( $wgWhitelistReadRegexp ) ) {
2404                         $name = $this->getPrefixedText();
2405                         // Check for regex whitelisting
2406                         foreach ( $wgWhitelistReadRegexp as $listItem ) {
2407                                 if ( preg_match( $listItem, $name ) ) {
2408                                         $whitelisted = true;
2409                                         break;
2410                                 }
2411                         }
2412                 }
2413
2414                 if ( !$whitelisted ) {
2415                         # If the title is not whitelisted, give extensions a chance to do so...
2416                         Hooks::run( 'TitleReadWhitelist', array( $this, $user, &$whitelisted ) );
2417                         if ( !$whitelisted ) {
2418                                 $errors[] = $this->missingPermissionError( $action, $short );
2419                         }
2420                 }
2421
2422                 return $errors;
2423         }
2424
2425         /**
2426          * Get a description array when the user doesn't have the right to perform
2427          * $action (i.e. when User::isAllowed() returns false)
2428          *
2429          * @param string $action The action to check
2430          * @param bool $short Short circuit on first error
2431          * @return array List of errors
2432          */
2433         private function missingPermissionError( $action, $short ) {
2434                 // We avoid expensive display logic for quickUserCan's and such
2435                 if ( $short ) {
2436                         return array( 'badaccess-group0' );
2437                 }
2438
2439                 $groups = array_map( array( 'User', 'makeGroupLinkWiki' ),
2440                         User::getGroupsWithPermission( $action ) );
2441
2442                 if ( count( $groups ) ) {
2443                         global $wgLang;
2444                         return array(
2445                                 'badaccess-groups',
2446                                 $wgLang->commaList( $groups ),
2447                                 count( $groups )
2448                         );
2449                 } else {
2450                         return array( 'badaccess-group0' );
2451                 }
2452         }
2453
2454         /**
2455          * Can $user perform $action on this page? This is an internal function,
2456          * which checks ONLY that previously checked by userCan (i.e. it leaves out
2457          * checks on wfReadOnly() and blocks)
2458          *
2459          * @param string $action Action that permission needs to be checked for
2460          * @param User $user User to check
2461          * @param string $rigor One of (quick,full,secure)
2462          *   - quick  : does cheap permission checks from slaves (usable for GUI creation)
2463          *   - full   : does cheap and expensive checks possibly from a slave
2464          *   - secure : does cheap and expensive checks, using the master as needed
2465          * @param bool $short Set this to true to stop after the first permission error.
2466          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
2467          */
2468         protected function getUserPermissionsErrorsInternal(
2469                 $action, $user, $rigor = 'secure', $short = false
2470         ) {
2471                 if ( $rigor === true ) {
2472                         $rigor = 'secure'; // b/c
2473                 } elseif ( $rigor === false ) {
2474                         $rigor = 'quick'; // b/c
2475                 } elseif ( !in_array( $rigor, array( 'quick', 'full', 'secure' ) ) ) {
2476                         throw new Exception( "Invalid rigor parameter '$rigor'." );
2477                 }
2478
2479                 # Read has special handling
2480                 if ( $action == 'read' ) {
2481                         $checks = array(
2482                                 'checkPermissionHooks',
2483                                 'checkReadPermissions',
2484                         );
2485                 # Don't call checkSpecialsAndNSPermissions or checkCSSandJSPermissions
2486                 # here as it will lead to duplicate error messages. This is okay to do
2487                 # since anywhere that checks for create will also check for edit, and
2488                 # those checks are called for edit.
2489                 } elseif ( $action == 'create' ) {
2490                         $checks = array(
2491                                 'checkQuickPermissions',
2492                                 'checkPermissionHooks',
2493                                 'checkPageRestrictions',
2494                                 'checkCascadingSourcesRestrictions',
2495                                 'checkActionPermissions',
2496                                 'checkUserBlock'
2497                         );
2498                 } else {
2499                         $checks = array(
2500                                 'checkQuickPermissions',
2501                                 'checkPermissionHooks',
2502                                 'checkSpecialsAndNSPermissions',
2503                                 'checkCSSandJSPermissions',
2504                                 'checkPageRestrictions',
2505                                 'checkCascadingSourcesRestrictions',
2506                                 'checkActionPermissions',
2507                                 'checkUserBlock'
2508                         );
2509                 }
2510
2511                 $errors = array();
2512                 while ( count( $checks ) > 0 &&
2513                                 !( $short && count( $errors ) > 0 ) ) {
2514                         $method = array_shift( $checks );
2515                         $errors = $this->$method( $action, $user, $errors, $rigor, $short );
2516                 }
2517
2518                 return $errors;
2519         }
2520
2521         /**
2522          * Get a filtered list of all restriction types supported by this wiki.
2523          * @param bool $exists True to get all restriction types that apply to
2524          * titles that do exist, False for all restriction types that apply to
2525          * titles that do not exist
2526          * @return array
2527          */
2528         public static function getFilteredRestrictionTypes( $exists = true ) {
2529                 global $wgRestrictionTypes;
2530                 $types = $wgRestrictionTypes;
2531                 if ( $exists ) {
2532                         # Remove the create restriction for existing titles
2533                         $types = array_diff( $types, array( 'create' ) );
2534                 } else {
2535                         # Only the create and upload restrictions apply to non-existing titles
2536                         $types = array_intersect( $types, array( 'create', 'upload' ) );
2537                 }
2538                 return $types;
2539         }
2540
2541         /**
2542          * Returns restriction types for the current Title
2543          *
2544          * @return array Applicable restriction types
2545          */
2546         public function getRestrictionTypes() {
2547                 if ( $this->isSpecialPage() ) {
2548                         return array();
2549                 }
2550
2551                 $types = self::getFilteredRestrictionTypes( $this->exists() );
2552
2553                 if ( $this->getNamespace() != NS_FILE ) {
2554                         # Remove the upload restriction for non-file titles
2555                         $types = array_diff( $types, array( 'upload' ) );
2556                 }
2557
2558                 Hooks::run( 'TitleGetRestrictionTypes', array( $this, &$types ) );
2559
2560                 wfDebug( __METHOD__ . ': applicable restrictions to [[' .
2561                         $this->getPrefixedText() . ']] are {' . implode( ',', $types ) . "}\n" );
2562
2563                 return $types;
2564         }
2565
2566         /**
2567          * Is this title subject to title protection?
2568          * Title protection is the one applied against creation of such title.
2569          *
2570          * @return array|bool An associative array representing any existent title
2571          *   protection, or false if there's none.
2572          */
2573         public function getTitleProtection() {
2574                 // Can't protect pages in special namespaces
2575                 if ( $this->getNamespace() < 0 ) {
2576                         return false;
2577                 }
2578
2579                 // Can't protect pages that exist.
2580                 if ( $this->exists() ) {
2581                         return false;
2582                 }
2583
2584                 if ( $this->mTitleProtection === null ) {
2585                         $dbr = wfGetDB( DB_SLAVE );
2586                         $res = $dbr->select(
2587                                 'protected_titles',
2588                                 array(
2589                                         'user' => 'pt_user',
2590                                         'reason' => 'pt_reason',
2591                                         'expiry' => 'pt_expiry',
2592                                         'permission' => 'pt_create_perm'
2593                                 ),
2594                                 array( 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ),
2595                                 __METHOD__
2596                         );
2597
2598                         // fetchRow returns false if there are no rows.
2599                         $row = $dbr->fetchRow( $res );
2600                         if ( $row ) {
2601                                 if ( $row['permission'] == 'sysop' ) {
2602                                         $row['permission'] = 'editprotected'; // B/C
2603                                 }
2604                                 if ( $row['permission'] == 'autoconfirmed' ) {
2605                                         $row['permission'] = 'editsemiprotected'; // B/C
2606                                 }
2607                                 $row['expiry'] = $dbr->decodeExpiry( $row['expiry'] );
2608                         }
2609                         $this->mTitleProtection = $row;
2610                 }
2611                 return $this->mTitleProtection;
2612         }
2613
2614         /**
2615          * Remove any title protection due to page existing
2616          */
2617         public function deleteTitleProtection() {
2618                 $dbw = wfGetDB( DB_MASTER );
2619
2620                 $dbw->delete(
2621                         'protected_titles',
2622                         array( 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ),
2623                         __METHOD__
2624                 );
2625                 $this->mTitleProtection = false;
2626         }
2627
2628         /**
2629          * Is this page "semi-protected" - the *only* protection levels are listed
2630          * in $wgSemiprotectedRestrictionLevels?
2631          *
2632          * @param string $action Action to check (default: edit)
2633          * @return bool
2634          */
2635         public function isSemiProtected( $action = 'edit' ) {
2636                 global $wgSemiprotectedRestrictionLevels;
2637
2638                 $restrictions = $this->getRestrictions( $action );
2639                 $semi = $wgSemiprotectedRestrictionLevels;
2640                 if ( !$restrictions || !$semi ) {
2641                         // Not protected, or all protection is full protection
2642                         return false;
2643                 }
2644
2645                 // Remap autoconfirmed to editsemiprotected for BC
2646                 foreach ( array_keys( $semi, 'autoconfirmed' ) as $key ) {
2647                         $semi[$key] = 'editsemiprotected';
2648                 }
2649                 foreach ( array_keys( $restrictions, 'autoconfirmed' ) as $key ) {
2650                         $restrictions[$key] = 'editsemiprotected';
2651                 }
2652
2653                 return !array_diff( $restrictions, $semi );
2654         }
2655
2656         /**
2657          * Does the title correspond to a protected article?
2658          *
2659          * @param string $action The action the page is protected from,
2660          * by default checks all actions.
2661          * @return bool
2662          */
2663         public function isProtected( $action = '' ) {
2664                 global $wgRestrictionLevels;
2665
2666                 $restrictionTypes = $this->getRestrictionTypes();
2667
2668                 # Special pages have inherent protection
2669                 if ( $this->isSpecialPage() ) {
2670                         return true;
2671                 }
2672
2673                 # Check regular protection levels
2674                 foreach ( $restrictionTypes as $type ) {
2675                         if ( $action == $type || $action == '' ) {
2676                                 $r = $this->getRestrictions( $type );
2677                                 foreach ( $wgRestrictionLevels as $level ) {
2678                                         if ( in_array( $level, $r ) && $level != '' ) {
2679                                                 return true;
2680                                         }
2681                                 }
2682                         }
2683                 }
2684
2685                 return false;
2686         }
2687
2688         /**
2689          * Determines if $user is unable to edit this page because it has been protected
2690          * by $wgNamespaceProtection.
2691          *
2692          * @param User $user User object to check permissions
2693          * @return bool
2694          */
2695         public function isNamespaceProtected( User $user ) {
2696                 global $wgNamespaceProtection;
2697
2698                 if ( isset( $wgNamespaceProtection[$this->mNamespace] ) ) {
2699                         foreach ( (array)$wgNamespaceProtection[$this->mNamespace] as $right ) {
2700                                 if ( $right != '' && !$user->isAllowed( $right ) ) {
2701                                         return true;
2702                                 }
2703                         }
2704                 }
2705                 return false;
2706         }
2707
2708         /**
2709          * Cascading protection: Return true if cascading restrictions apply to this page, false if not.
2710          *
2711          * @return bool If the page is subject to cascading restrictions.
2712          */
2713         public function isCascadeProtected() {
2714                 list( $sources, /* $restrictions */ ) = $this->getCascadeProtectionSources( false );
2715                 return ( $sources > 0 );
2716         }
2717
2718         /**
2719          * Determines whether cascading protection sources have already been loaded from
2720          * the database.
2721          *
2722          * @param bool $getPages True to check if the pages are loaded, or false to check
2723          * if the status is loaded.
2724          * @return bool Whether or not the specified information has been loaded
2725          * @since 1.23
2726          */
2727         public function areCascadeProtectionSourcesLoaded( $getPages = true ) {
2728                 return $getPages ? $this->mCascadeSources !== null : $this->mHasCascadingRestrictions !== null;
2729         }
2730
2731         /**
2732          * Cascading protection: Get the source of any cascading restrictions on this page.
2733          *
2734          * @param bool $getPages Whether or not to retrieve the actual pages
2735          *        that the restrictions have come from and the actual restrictions
2736          *        themselves.
2737          * @return array Two elements: First is an array of Title objects of the
2738          *        pages from which cascading restrictions have come, false for
2739          *        none, or true if such restrictions exist but $getPages was not
2740          *        set. Second is an array like that returned by
2741          *        Title::getAllRestrictions(), or an empty array if $getPages is
2742          *        false.
2743          */
2744         public function getCascadeProtectionSources( $getPages = true ) {
2745                 $pagerestrictions = array();
2746
2747                 if ( $this->mCascadeSources !== null && $getPages ) {
2748                         return array( $this->mCascadeSources, $this->mCascadingRestrictions );
2749                 } elseif ( $this->mHasCascadingRestrictions !== null && !$getPages ) {
2750                         return array( $this->mHasCascadingRestrictions, $pagerestrictions );
2751                 }
2752
2753                 $dbr = wfGetDB( DB_SLAVE );
2754
2755                 if ( $this->getNamespace() == NS_FILE ) {
2756                         $tables = array( 'imagelinks', 'page_restrictions' );
2757                         $where_clauses = array(
2758                                 'il_to' => $this->getDBkey(),
2759                                 'il_from=pr_page',
2760                                 'pr_cascade' => 1
2761                         );
2762                 } else {
2763                         $tables = array( 'templatelinks', 'page_restrictions' );
2764                         $where_clauses = array(
2765                                 'tl_namespace' => $this->getNamespace(),
2766                                 'tl_title' => $this->getDBkey(),
2767                                 'tl_from=pr_page',
2768                                 'pr_cascade' => 1
2769                         );
2770                 }
2771
2772                 if ( $getPages ) {
2773                         $cols = array( 'pr_page', 'page_namespace', 'page_title',
2774                                 'pr_expiry', 'pr_type', 'pr_level' );
2775                         $where_clauses[] = 'page_id=pr_page';
2776                         $tables[] = 'page';
2777                 } else {
2778                         $cols = array( 'pr_expiry' );
2779                 }
2780
2781                 $res = $dbr->select( $tables, $cols, $where_clauses, __METHOD__ );
2782
2783                 $sources = $getPages ? array() : false;
2784                 $now = wfTimestampNow();
2785
2786                 foreach ( $res as $row ) {
2787                         $expiry = $dbr->decodeExpiry( $row->pr_expiry );
2788                         if ( $expiry > $now ) {
2789                                 if ( $getPages ) {
2790                                         $page_id = $row->pr_page;
2791                                         $page_ns = $row->page_namespace;
2792                                         $page_title = $row->page_title;
2793                                         $sources[$page_id] = Title::makeTitle( $page_ns, $page_title );
2794                                         # Add groups needed for each restriction type if its not already there
2795                                         # Make sure this restriction type still exists
2796
2797                                         if ( !isset( $pagerestrictions[$row->pr_type] ) ) {
2798                                                 $pagerestrictions[$row->pr_type] = array();
2799                                         }
2800
2801                                         if (
2802                                                 isset( $pagerestrictions[$row->pr_type] )
2803                                                 && !in_array( $row->pr_level, $pagerestrictions[$row->pr_type] )
2804                                         ) {
2805                                                 $pagerestrictions[$row->pr_type][] = $row->pr_level;
2806                                         }
2807                                 } else {
2808                                         $sources = true;
2809                                 }
2810                         }
2811                 }
2812
2813                 if ( $getPages ) {
2814                         $this->mCascadeSources = $sources;
2815                         $this->mCascadingRestrictions = $pagerestrictions;
2816                 } else {
2817                         $this->mHasCascadingRestrictions = $sources;
2818                 }
2819
2820                 return array( $sources, $pagerestrictions );
2821         }
2822
2823         /**
2824          * Accessor for mRestrictionsLoaded
2825          *
2826          * @return bool Whether or not the page's restrictions have already been
2827          * loaded from the database
2828          * @since 1.23
2829          */
2830         public function areRestrictionsLoaded() {
2831                 return $this->mRestrictionsLoaded;
2832         }
2833
2834         /**
2835          * Accessor/initialisation for mRestrictions
2836          *
2837          * @param string $action Action that permission needs to be checked for
2838          * @return array Restriction levels needed to take the action. All levels are
2839          *     required. Note that restriction levels are normally user rights, but 'sysop'
2840          *     and 'autoconfirmed' are also allowed for backwards compatibility. These should
2841          *     be mapped to 'editprotected' and 'editsemiprotected' respectively.
2842          */
2843         public function getRestrictions( $action ) {
2844                 if ( !$this->mRestrictionsLoaded ) {
2845                         $this->loadRestrictions();
2846                 }
2847                 return isset( $this->mRestrictions[$action] )
2848                                 ? $this->mRestrictions[$action]
2849                                 : array();
2850         }
2851
2852         /**
2853          * Accessor/initialisation for mRestrictions
2854          *
2855          * @return array Keys are actions, values are arrays as returned by
2856          *     Title::getRestrictions()
2857          * @since 1.23
2858          */
2859         public function getAllRestrictions() {
2860                 if ( !$this->mRestrictionsLoaded ) {
2861                         $this->loadRestrictions();
2862                 }
2863                 return $this->mRestrictions;
2864         }
2865
2866         /**
2867          * Get the expiry time for the restriction against a given action
2868          *
2869          * @param string $action
2870          * @return string|bool 14-char timestamp, or 'infinity' if the page is protected forever
2871          *     or not protected at all, or false if the action is not recognised.
2872          */
2873         public function getRestrictionExpiry( $action ) {
2874                 if ( !$this->mRestrictionsLoaded ) {
2875                         $this->loadRestrictions();
2876                 }
2877                 return isset( $this->mRestrictionsExpiry[$action] ) ? $this->mRestrictionsExpiry[$action] : false;
2878         }
2879
2880         /**
2881          * Returns cascading restrictions for the current article
2882          *
2883          * @return bool
2884          */
2885         function areRestrictionsCascading() {
2886                 if ( !$this->mRestrictionsLoaded ) {
2887                         $this->loadRestrictions();
2888                 }
2889
2890                 return $this->mCascadeRestriction;
2891         }
2892
2893         /**
2894          * Loads a string into mRestrictions array
2895          *
2896          * @param ResultWrapper $res Resource restrictions as an SQL result.
2897          * @param string $oldFashionedRestrictions Comma-separated list of page
2898          *        restrictions from page table (pre 1.10)
2899          */
2900         private function loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions = null ) {
2901                 $rows = array();
2902
2903                 foreach ( $res as $row ) {
2904                         $rows[] = $row;
2905                 }
2906
2907                 $this->loadRestrictionsFromRows( $rows, $oldFashionedRestrictions );
2908         }
2909
2910         /**
2911          * Compiles list of active page restrictions from both page table (pre 1.10)
2912          * and page_restrictions table for this existing page.
2913          * Public for usage by LiquidThreads.
2914          *
2915          * @param array $rows Array of db result objects
2916          * @param string $oldFashionedRestrictions Comma-separated list of page
2917          *   restrictions from page table (pre 1.10)
2918          */
2919         public function loadRestrictionsFromRows( $rows, $oldFashionedRestrictions = null ) {
2920                 $dbr = wfGetDB( DB_SLAVE );
2921
2922                 $restrictionTypes = $this->getRestrictionTypes();
2923
2924                 foreach ( $restrictionTypes as $type ) {
2925                         $this->mRestrictions[$type] = array();
2926                         $this->mRestrictionsExpiry[$type] = 'infinity';
2927                 }
2928
2929                 $this->mCascadeRestriction = false;
2930
2931                 # Backwards-compatibility: also load the restrictions from the page record (old format).
2932                 if ( $oldFashionedRestrictions !== null ) {
2933                         $this->mOldRestrictions = $oldFashionedRestrictions;
2934                 }
2935
2936                 if ( $this->mOldRestrictions === false ) {
2937                         $this->mOldRestrictions = $dbr->selectField( 'page', 'page_restrictions',
2938                                 array( 'page_id' => $this->getArticleID() ), __METHOD__ );
2939                 }
2940
2941                 if ( $this->mOldRestrictions != '' ) {
2942                         foreach ( explode( ':', trim( $this->mOldRestrictions ) ) as $restrict ) {
2943                                 $temp = explode( '=', trim( $restrict ) );
2944                                 if ( count( $temp ) == 1 ) {
2945                                         // old old format should be treated as edit/move restriction
2946                                         $this->mRestrictions['edit'] = explode( ',', trim( $temp[0] ) );
2947                                         $this->mRestrictions['move'] = explode( ',', trim( $temp[0] ) );
2948                                 } else {
2949                                         $restriction = trim( $temp[1] );
2950                                         if ( $restriction != '' ) { // some old entries are empty
2951                                                 $this->mRestrictions[$temp[0]] = explode( ',', $restriction );
2952                                         }
2953                                 }
2954                         }
2955                 }
2956
2957                 if ( count( $rows ) ) {
2958                         # Current system - load second to make them override.
2959                         $now = wfTimestampNow();
2960
2961                         # Cycle through all the restrictions.
2962                         foreach ( $rows as $row ) {
2963
2964                                 // Don't take care of restrictions types that aren't allowed
2965                                 if ( !in_array( $row->pr_type, $restrictionTypes ) ) {
2966                                         continue;
2967                                 }
2968
2969                                 // This code should be refactored, now that it's being used more generally,
2970                                 // But I don't really see any harm in leaving it in Block for now -werdna
2971                                 $expiry = $dbr->decodeExpiry( $row->pr_expiry );
2972
2973                                 // Only apply the restrictions if they haven't expired!
2974                                 if ( !$expiry || $expiry > $now ) {
2975                                         $this->mRestrictionsExpiry[$row->pr_type] = $expiry;
2976                                         $this->mRestrictions[$row->pr_type] = explode( ',', trim( $row->pr_level ) );
2977
2978                                         $this->mCascadeRestriction |= $row->pr_cascade;
2979                                 }
2980                         }
2981                 }
2982
2983                 $this->mRestrictionsLoaded = true;
2984         }
2985
2986         /**
2987          * Load restrictions from the page_restrictions table
2988          *
2989          * @param string $oldFashionedRestrictions Comma-separated list of page
2990          *   restrictions from page table (pre 1.10)
2991          */
2992         public function loadRestrictions( $oldFashionedRestrictions = null ) {
2993                 if ( !$this->mRestrictionsLoaded ) {
2994                         $dbr = wfGetDB( DB_SLAVE );
2995                         if ( $this->exists() ) {
2996                                 $res = $dbr->select(
2997                                         'page_restrictions',
2998                                         array( 'pr_type', 'pr_expiry', 'pr_level', 'pr_cascade' ),
2999                                         array( 'pr_page' => $this->getArticleID() ),
3000                                         __METHOD__
3001                                 );
3002
3003                                 $this->loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions );
3004                         } else {
3005                                 $title_protection = $this->getTitleProtection();
3006
3007                                 if ( $title_protection ) {
3008                                         $now = wfTimestampNow();
3009                                         $expiry = $dbr->decodeExpiry( $title_protection['expiry'] );
3010
3011                                         if ( !$expiry || $expiry > $now ) {
3012                                                 // Apply the restrictions
3013                                                 $this->mRestrictionsExpiry['create'] = $expiry;
3014                                                 $this->mRestrictions['create'] = explode( ',', trim( $title_protection['permission'] ) );
3015                                         } else { // Get rid of the old restrictions
3016                                                 $this->mTitleProtection = false;
3017                                         }
3018                                 } else {
3019                                         $this->mRestrictionsExpiry['create'] = 'infinity';
3020                                 }
3021                                 $this->mRestrictionsLoaded = true;
3022                         }
3023                 }
3024         }
3025
3026         /**
3027          * Flush the protection cache in this object and force reload from the database.
3028          * This is used when updating protection from WikiPage::doUpdateRestrictions().
3029          */
3030         public function flushRestrictions() {
3031                 $this->mRestrictionsLoaded = false;
3032                 $this->mTitleProtection = null;
3033         }
3034
3035         /**
3036          * Purge expired restrictions from the page_restrictions table
3037          */
3038         static function purgeExpiredRestrictions() {
3039                 if ( wfReadOnly() ) {
3040                         return;
3041                 }
3042
3043                 $method = __METHOD__;
3044                 $dbw = wfGetDB( DB_MASTER );
3045                 $dbw->onTransactionIdle( function () use ( $dbw, $method ) {
3046                         $dbw->delete(
3047                                 'page_restrictions',
3048                                 array( 'pr_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ),
3049                                 $method
3050                         );
3051                         $dbw->delete(
3052                                 'protected_titles',
3053                                 array( 'pt_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ),
3054                                 $method
3055                         );
3056                 } );
3057         }
3058
3059         /**
3060          * Does this have subpages?  (Warning, usually requires an extra DB query.)
3061          *
3062          * @return bool
3063          */
3064         public function hasSubpages() {
3065                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
3066                         # Duh
3067                         return false;
3068                 }
3069
3070                 # We dynamically add a member variable for the purpose of this method
3071                 # alone to cache the result.  There's no point in having it hanging
3072                 # around uninitialized in every Title object; therefore we only add it
3073                 # if needed and don't declare it statically.
3074                 if ( $this->mHasSubpages === null ) {
3075                         $this->mHasSubpages = false;
3076                         $subpages = $this->getSubpages( 1 );
3077                         if ( $subpages instanceof TitleArray ) {
3078                                 $this->mHasSubpages = (bool)$subpages->count();
3079                         }
3080                 }
3081
3082                 return $this->mHasSubpages;
3083         }
3084
3085         /**
3086          * Get all subpages of this page.
3087          *
3088          * @param int $limit Maximum number of subpages to fetch; -1 for no limit
3089          * @return TitleArray|array TitleArray, or empty array if this page's namespace
3090          *  doesn't allow subpages
3091          */
3092         public function getSubpages( $limit = -1 ) {
3093                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3094                         return array();
3095                 }
3096
3097                 $dbr = wfGetDB( DB_SLAVE );
3098                 $conds['page_namespace'] = $this->getNamespace();
3099                 $conds[] = 'page_title ' . $dbr->buildLike( $this->getDBkey() . '/', $dbr->anyString() );
3100                 $options = array();
3101                 if ( $limit > -1 ) {
3102                         $options['LIMIT'] = $limit;
3103                 }
3104                 $this->mSubpages = TitleArray::newFromResult(
3105                         $dbr->select( 'page',
3106                                 array( 'page_id', 'page_namespace', 'page_title', 'page_is_redirect' ),
3107                                 $conds,
3108                                 __METHOD__,
3109                                 $options
3110                         )
3111                 );
3112                 return $this->mSubpages;
3113         }
3114
3115         /**
3116          * Is there a version of this page in the deletion archive?
3117          *
3118          * @return int The number of archived revisions
3119          */
3120         public function isDeleted() {
3121                 if ( $this->getNamespace() < 0 ) {
3122                         $n = 0;
3123                 } else {
3124                         $dbr = wfGetDB( DB_SLAVE );
3125
3126                         $n = $dbr->selectField( 'archive', 'COUNT(*)',
3127                                 array( 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ),
3128                                 __METHOD__
3129                         );
3130                         if ( $this->getNamespace() == NS_FILE ) {
3131                                 $n += $dbr->selectField( 'filearchive', 'COUNT(*)',
3132                                         array( 'fa_name' => $this->getDBkey() ),
3133                                         __METHOD__
3134                                 );
3135                         }
3136                 }
3137                 return (int)$n;
3138         }
3139
3140         /**
3141          * Is there a version of this page in the deletion archive?
3142          *
3143          * @return bool
3144          */
3145         public function isDeletedQuick() {
3146                 if ( $this->getNamespace() < 0 ) {
3147                         return false;
3148                 }
3149                 $dbr = wfGetDB( DB_SLAVE );
3150                 $deleted = (bool)$dbr->selectField( 'archive', '1',
3151                         array( 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ),
3152                         __METHOD__
3153                 );
3154                 if ( !$deleted && $this->getNamespace() == NS_FILE ) {
3155                         $deleted = (bool)$dbr->selectField( 'filearchive', '1',
3156                                 array( 'fa_name' => $this->getDBkey() ),
3157                                 __METHOD__
3158                         );
3159                 }
3160                 return $deleted;
3161         }
3162
3163         /**
3164          * Get the article ID for this Title from the link cache,
3165          * adding it if necessary
3166          *
3167          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select
3168          *  for update
3169          * @return int The ID
3170          */
3171         public function getArticleID( $flags = 0 ) {
3172                 if ( $this->getNamespace() < 0 ) {
3173                         $this->mArticleID = 0;
3174                         return $this->mArticleID;
3175                 }
3176                 $linkCache = LinkCache::singleton();
3177                 if ( $flags & self::GAID_FOR_UPDATE ) {
3178                         $oldUpdate = $linkCache->forUpdate( true );
3179                         $linkCache->clearLink( $this );
3180                         $this->mArticleID = $linkCache->addLinkObj( $this );
3181                         $linkCache->forUpdate( $oldUpdate );
3182                 } else {
3183                         if ( -1 == $this->mArticleID ) {
3184                                 $this->mArticleID = $linkCache->addLinkObj( $this );
3185                         }
3186                 }
3187                 return $this->mArticleID;
3188         }
3189
3190         /**
3191          * Is this an article that is a redirect page?
3192          * Uses link cache, adding it if necessary
3193          *
3194          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3195          * @return bool
3196          */
3197         public function isRedirect( $flags = 0 ) {
3198                 if ( !is_null( $this->mRedirect ) ) {
3199                         return $this->mRedirect;
3200                 }
3201                 if ( !$this->getArticleID( $flags ) ) {
3202                         $this->mRedirect = false;
3203                         return $this->mRedirect;
3204                 }
3205
3206                 $linkCache = LinkCache::singleton();
3207                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3208                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'redirect' );
3209                 if ( $cached === null ) {
3210                         # Trust LinkCache's state over our own
3211                         # LinkCache is telling us that the page doesn't exist, despite there being cached
3212                         # data relating to an existing page in $this->mArticleID. Updaters should clear
3213                         # LinkCache as appropriate, or use $flags = Title::GAID_FOR_UPDATE. If that flag is
3214                         # set, then LinkCache will definitely be up to date here, since getArticleID() forces
3215                         # LinkCache to refresh its data from the master.
3216                         $this->mRedirect = false;
3217                         return $this->mRedirect;
3218                 }
3219
3220                 $this->mRedirect = (bool)$cached;
3221
3222                 return $this->mRedirect;
3223         }
3224
3225         /**
3226          * What is the length of this page?
3227          * Uses link cache, adding it if necessary
3228          *
3229          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3230          * @return int
3231          */
3232         public function getLength( $flags = 0 ) {
3233                 if ( $this->mLength != -1 ) {
3234                         return $this->mLength;
3235                 }
3236                 if ( !$this->getArticleID( $flags ) ) {
3237                         $this->mLength = 0;
3238                         return $this->mLength;
3239                 }
3240                 $linkCache = LinkCache::singleton();
3241                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3242                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'length' );
3243                 if ( $cached === null ) {
3244                         # Trust LinkCache's state over our own, as for isRedirect()
3245                         $this->mLength = 0;
3246                         return $this->mLength;
3247                 }
3248
3249                 $this->mLength = intval( $cached );
3250
3251                 return $this->mLength;
3252         }
3253
3254         /**
3255          * What is the page_latest field for this page?
3256          *
3257          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3258          * @return int Int or 0 if the page doesn't exist
3259          */
3260         public function getLatestRevID( $flags = 0 ) {
3261                 if ( !( $flags & Title::GAID_FOR_UPDATE ) && $this->mLatestID !== false ) {
3262                         return intval( $this->mLatestID );
3263                 }
3264                 if ( !$this->getArticleID( $flags ) ) {
3265                         $this->mLatestID = 0;
3266                         return $this->mLatestID;
3267                 }
3268                 $linkCache = LinkCache::singleton();
3269                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3270                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'revision' );
3271                 if ( $cached === null ) {
3272                         # Trust LinkCache's state over our own, as for isRedirect()
3273                         $this->mLatestID = 0;
3274                         return $this->mLatestID;
3275                 }
3276
3277                 $this->mLatestID = intval( $cached );
3278
3279                 return $this->mLatestID;
3280         }
3281
3282         /**
3283          * This clears some fields in this object, and clears any associated
3284          * keys in the "bad links" section of the link cache.
3285          *
3286          * - This is called from WikiPage::doEdit() and WikiPage::insertOn() to allow
3287          * loading of the new page_id. It's also called from
3288          * WikiPage::doDeleteArticleReal()
3289          *
3290          * @param int $newid The new Article ID
3291          */
3292         public function resetArticleID( $newid ) {
3293                 $linkCache = LinkCache::singleton();
3294                 $linkCache->clearLink( $this );
3295
3296                 if ( $newid === false ) {
3297                         $this->mArticleID = -1;
3298                 } else {
3299                         $this->mArticleID = intval( $newid );
3300                 }
3301                 $this->mRestrictionsLoaded = false;
3302                 $this->mRestrictions = array();
3303                 $this->mOldRestrictions = false;
3304                 $this->mRedirect = null;
3305                 $this->mLength = -1;
3306                 $this->mLatestID = false;
3307                 $this->mContentModel = false;
3308                 $this->mEstimateRevisions = null;
3309                 $this->mPageLanguage = false;
3310                 $this->mDbPageLanguage = null;
3311                 $this->mIsBigDeletion = null;
3312         }
3313
3314         public static function clearCaches() {
3315                 $linkCache = LinkCache::singleton();
3316                 $linkCache->clear();
3317
3318                 $titleCache = self::getTitleCache();
3319                 $titleCache->clear();
3320         }
3321
3322         /**
3323          * Capitalize a text string for a title if it belongs to a namespace that capitalizes
3324          *
3325          * @param string $text Containing title to capitalize
3326          * @param int $ns Namespace index, defaults to NS_MAIN
3327          * @return string Containing capitalized title
3328          */
3329         public static function capitalize( $text, $ns = NS_MAIN ) {
3330                 global $wgContLang;
3331
3332                 if ( MWNamespace::isCapitalized( $ns ) ) {
3333                         return $wgContLang->ucfirst( $text );
3334                 } else {
3335                         return $text;
3336                 }
3337         }
3338
3339         /**
3340          * Secure and split - main initialisation function for this object
3341          *
3342          * Assumes that mDbkeyform has been set, and is urldecoded
3343          * and uses underscores, but not otherwise munged.  This function
3344          * removes illegal characters, splits off the interwiki and
3345          * namespace prefixes, sets the other forms, and canonicalizes
3346          * everything.
3347          *
3348          * @throws MalformedTitleException On invalid titles
3349          * @return bool True on success
3350          */
3351         private function secureAndSplit() {
3352                 # Initialisation
3353                 $this->mInterwiki = '';
3354                 $this->mFragment = '';
3355                 $this->mNamespace = $this->mDefaultNamespace; # Usually NS_MAIN
3356
3357                 $dbkey = $this->mDbkeyform;
3358
3359                 // @note: splitTitleString() is a temporary hack to allow MediaWikiTitleCodec to share
3360                 //        the parsing code with Title, while avoiding massive refactoring.
3361                 // @todo: get rid of secureAndSplit, refactor parsing code.
3362                 $titleParser = self::getTitleParser();
3363                 // MalformedTitleException can be thrown here
3364                 $parts = $titleParser->splitTitleString( $dbkey, $this->getDefaultNamespace() );
3365
3366                 # Fill fields
3367                 $this->setFragment( '#' . $parts['fragment'] );
3368                 $this->mInterwiki = $parts['interwiki'];
3369                 $this->mLocalInterwiki = $parts['local_interwiki'];
3370                 $this->mNamespace = $parts['namespace'];
3371                 $this->mUserCaseDBKey = $parts['user_case_dbkey'];
3372
3373                 $this->mDbkeyform = $parts['dbkey'];
3374                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
3375                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
3376
3377                 # We already know that some pages won't be in the database!
3378                 if ( $this->isExternal() || $this->mNamespace == NS_SPECIAL ) {
3379                         $this->mArticleID = 0;
3380                 }
3381
3382                 return true;
3383         }
3384
3385         /**
3386          * Get an array of Title objects linking to this Title
3387          * Also stores the IDs in the link cache.
3388          *
3389          * WARNING: do not use this function on arbitrary user-supplied titles!
3390          * On heavily-used templates it will max out the memory.
3391          *
3392          * @param array $options May be FOR UPDATE
3393          * @param string $table Table name
3394          * @param string $prefix Fields prefix
3395          * @return Title[] Array of Title objects linking here
3396          */
3397         public function getLinksTo( $options = array(), $table = 'pagelinks', $prefix = 'pl' ) {
3398                 if ( count( $options ) > 0 ) {
3399                         $db = wfGetDB( DB_MASTER );
3400                 } else {
3401                         $db = wfGetDB( DB_SLAVE );
3402                 }
3403
3404                 $res = $db->select(
3405                         array( 'page', $table ),
3406                         self::getSelectFields(),
3407                         array(
3408                                 "{$prefix}_from=page_id",
3409                                 "{$prefix}_namespace" => $this->getNamespace(),
3410                                 "{$prefix}_title" => $this->getDBkey() ),
3411                         __METHOD__,
3412                         $options
3413                 );
3414
3415                 $retVal = array();
3416                 if ( $res->numRows() ) {
3417                         $linkCache = LinkCache::singleton();
3418                         foreach ( $res as $row ) {
3419                                 $titleObj = Title::makeTitle( $row->page_namespace, $row->page_title );
3420                                 if ( $titleObj ) {
3421                                         $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3422                                         $retVal[] = $titleObj;
3423                                 }
3424                         }
3425                 }
3426                 return $retVal;
3427         }
3428
3429         /**
3430          * Get an array of Title objects using this Title as a template
3431          * Also stores the IDs in the link cache.
3432          *
3433          * WARNING: do not use this function on arbitrary user-supplied titles!
3434          * On heavily-used templates it will max out the memory.
3435          *
3436          * @param array $options May be FOR UPDATE
3437          * @return Title[] Array of Title the Title objects linking here
3438          */
3439         public function getTemplateLinksTo( $options = array() ) {
3440                 return $this->getLinksTo( $options, 'templatelinks', 'tl' );
3441         }
3442
3443         /**
3444          * Get an array of Title objects linked from this Title
3445          * Also stores the IDs in the link cache.
3446          *
3447          * WARNING: do not use this function on arbitrary user-supplied titles!
3448          * On heavily-used templates it will max out the memory.
3449          *
3450          * @param array $options May be FOR UPDATE
3451          * @param string $table Table name
3452          * @param string $prefix Fields prefix
3453          * @return array Array of Title objects linking here
3454          */
3455         public function getLinksFrom( $options = array(), $table = 'pagelinks', $prefix = 'pl' ) {
3456                 $id = $this->getArticleID();
3457
3458                 # If the page doesn't exist; there can't be any link from this page
3459                 if ( !$id ) {
3460                         return array();
3461                 }
3462
3463                 if ( count( $options ) > 0 ) {
3464                         $db = wfGetDB( DB_MASTER );
3465                 } else {
3466                         $db = wfGetDB( DB_SLAVE );
3467                 }
3468
3469                 $blNamespace = "{$prefix}_namespace";
3470                 $blTitle = "{$prefix}_title";
3471
3472                 $res = $db->select(
3473                         array( $table, 'page' ),
3474                         array_merge(
3475                                 array( $blNamespace, $blTitle ),
3476                                 WikiPage::selectFields()
3477                         ),
3478                         array( "{$prefix}_from" => $id ),
3479                         __METHOD__,
3480                         $options,
3481                         array( 'page' => array(
3482                                 'LEFT JOIN',
3483                                 array( "page_namespace=$blNamespace", "page_title=$blTitle" )
3484                         ) )
3485                 );
3486
3487                 $retVal = array();
3488                 $linkCache = LinkCache::singleton();
3489                 foreach ( $res as $row ) {
3490                         if ( $row->page_id ) {
3491                                 $titleObj = Title::newFromRow( $row );
3492                         } else {
3493                                 $titleObj = Title::makeTitle( $row->$blNamespace, $row->$blTitle );
3494                                 $linkCache->addBadLinkObj( $titleObj );
3495                         }
3496                         $retVal[] = $titleObj;
3497                 }
3498
3499                 return $retVal;
3500         }
3501
3502         /**
3503          * Get an array of Title objects used on this Title as a template
3504          * Also stores the IDs in the link cache.
3505          *
3506          * WARNING: do not use this function on arbitrary user-supplied titles!
3507          * On heavily-used templates it will max out the memory.
3508          *
3509          * @param array $options May be FOR UPDATE
3510          * @return Title[] Array of Title the Title objects used here
3511          */
3512         public function getTemplateLinksFrom( $options = array() ) {
3513                 return $this->getLinksFrom( $options, 'templatelinks', 'tl' );
3514         }
3515
3516         /**
3517          * Get an array of Title objects referring to non-existent articles linked
3518          * from this page.
3519          *
3520          * @todo check if needed (used only in SpecialBrokenRedirects.php, and
3521          *   should use redirect table in this case).
3522          * @return Title[] Array of Title the Title objects
3523          */
3524         public function getBrokenLinksFrom() {
3525                 if ( $this->getArticleID() == 0 ) {
3526                         # All links from article ID 0 are false positives
3527                         return array();
3528                 }
3529
3530                 $dbr = wfGetDB( DB_SLAVE );
3531                 $res = $dbr->select(
3532                         array( 'page', 'pagelinks' ),
3533                         array( 'pl_namespace', 'pl_title' ),
3534                         array(
3535                                 'pl_from' => $this->getArticleID(),
3536                                 'page_namespace IS NULL'
3537                         ),
3538                         __METHOD__, array(),
3539                         array(
3540                                 'page' => array(
3541                                         'LEFT JOIN',
3542                                         array( 'pl_namespace=page_namespace', 'pl_title=page_title' )
3543                                 )
3544                         )
3545                 );
3546
3547                 $retVal = array();
3548                 foreach ( $res as $row ) {
3549                         $retVal[] = Title::makeTitle( $row->pl_namespace, $row->pl_title );
3550                 }
3551                 return $retVal;
3552         }
3553
3554         /**
3555          * Get a list of URLs to purge from the Squid cache when this
3556          * page changes
3557          *
3558          * @return string[] Array of String the URLs
3559          */
3560         public function getSquidURLs() {
3561                 $urls = array(
3562                         $this->getInternalURL(),
3563                         $this->getInternalURL( 'action=history' )
3564                 );
3565
3566                 $pageLang = $this->getPageLanguage();
3567                 if ( $pageLang->hasVariants() ) {
3568                         $variants = $pageLang->getVariants();
3569                         foreach ( $variants as $vCode ) {
3570                                 $urls[] = $this->getInternalURL( '', $vCode );
3571                         }
3572                 }
3573
3574                 // If we are looking at a css/js user subpage, purge the action=raw.
3575                 if ( $this->isJsSubpage() ) {
3576                         $urls[] = $this->getInternalUrl( 'action=raw&ctype=text/javascript' );
3577                 } elseif ( $this->isCssSubpage() ) {
3578                         $urls[] = $this->getInternalUrl( 'action=raw&ctype=text/css' );
3579                 }
3580
3581                 Hooks::run( 'TitleSquidURLs', array( $this, &$urls ) );
3582                 return $urls;
3583         }
3584
3585         /**
3586          * Purge all applicable Squid URLs
3587          */
3588         public function purgeSquid() {
3589                 global $wgUseSquid;
3590                 if ( $wgUseSquid ) {
3591                         $urls = $this->getSquidURLs();
3592                         $u = new SquidUpdate( $urls );
3593                         $u->doUpdate();
3594                 }
3595         }
3596
3597         /**
3598          * Move this page without authentication
3599          *
3600          * @deprecated since 1.25 use MovePage class instead
3601          * @param Title $nt The new page Title
3602          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3603          */
3604         public function moveNoAuth( &$nt ) {
3605                 wfDeprecated( __METHOD__, '1.25' );
3606                 return $this->moveTo( $nt, false );
3607         }
3608
3609         /**
3610          * Check whether a given move operation would be valid.
3611          * Returns true if ok, or a getUserPermissionsErrors()-like array otherwise
3612          *
3613          * @deprecated since 1.25, use MovePage's methods instead
3614          * @param Title $nt The new title
3615          * @param bool $auth Whether to check user permissions (uses $wgUser)
3616          * @param string $reason Is the log summary of the move, used for spam checking
3617          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3618          */
3619         public function isValidMoveOperation( &$nt, $auth = true, $reason = '' ) {
3620                 global $wgUser;
3621
3622                 if ( !( $nt instanceof Title ) ) {
3623                         // Normally we'd add this to $errors, but we'll get
3624                         // lots of syntax errors if $nt is not an object
3625                         return array( array( 'badtitletext' ) );
3626                 }
3627
3628                 $mp = new MovePage( $this, $nt );
3629                 $errors = $mp->isValidMove()->getErrorsArray();
3630                 if ( $auth ) {
3631                         $errors = wfMergeErrorArrays(
3632                                 $errors,
3633                                 $mp->checkPermissions( $wgUser, $reason )->getErrorsArray()
3634                         );
3635                 }
3636
3637                 return $errors ?: true;
3638         }
3639
3640         /**
3641          * Check if the requested move target is a valid file move target
3642          * @todo move this to MovePage
3643          * @param Title $nt Target title
3644          * @return array List of errors
3645          */
3646         protected function validateFileMoveOperation( $nt ) {
3647                 global $wgUser;
3648
3649                 $errors = array();
3650
3651                 $destFile = wfLocalFile( $nt );
3652                 $destFile->load( File::READ_LATEST );
3653                 if ( !$wgUser->isAllowed( 'reupload-shared' )
3654                         && !$destFile->exists() && wfFindFile( $nt )
3655                 ) {
3656                         $errors[] = array( 'file-exists-sharedrepo' );
3657                 }
3658
3659                 return $errors;
3660         }
3661
3662         /**
3663          * Move a title to a new location
3664          *
3665          * @deprecated since 1.25, use the MovePage class instead
3666          * @param Title $nt The new title
3667          * @param bool $auth Indicates whether $wgUser's permissions
3668          *  should be checked
3669          * @param string $reason The reason for the move
3670          * @param bool $createRedirect Whether to create a redirect from the old title to the new title.
3671          *  Ignored if the user doesn't have the suppressredirect right.
3672          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3673          */
3674         public function moveTo( &$nt, $auth = true, $reason = '', $createRedirect = true ) {
3675                 global $wgUser;
3676                 $err = $this->isValidMoveOperation( $nt, $auth, $reason );
3677                 if ( is_array( $err ) ) {
3678                         // Auto-block user's IP if the account was "hard" blocked
3679                         $wgUser->spreadAnyEditBlock();
3680                         return $err;
3681                 }
3682                 // Check suppressredirect permission
3683                 if ( $auth && !$wgUser->isAllowed( 'suppressredirect' ) ) {
3684                         $createRedirect = true;
3685                 }
3686
3687                 $mp = new MovePage( $this, $nt );
3688                 $status = $mp->move( $wgUser, $reason, $createRedirect );
3689                 if ( $status->isOK() ) {
3690                         return true;
3691                 } else {
3692                         return $status->getErrorsArray();
3693                 }
3694         }
3695
3696         /**
3697          * Move this page's subpages to be subpages of $nt
3698          *
3699          * @param Title $nt Move target
3700          * @param bool $auth Whether $wgUser's permissions should be checked
3701          * @param string $reason The reason for the move
3702          * @param bool $createRedirect Whether to create redirects from the old subpages to
3703          *     the new ones Ignored if the user doesn't have the 'suppressredirect' right
3704          * @return array Array with old page titles as keys, and strings (new page titles) or
3705          *     arrays (errors) as values, or an error array with numeric indices if no pages
3706          *     were moved
3707          */
3708         public function moveSubpages( $nt, $auth = true, $reason = '', $createRedirect = true ) {
3709                 global $wgMaximumMovedPages;
3710                 // Check permissions
3711                 if ( !$this->userCan( 'move-subpages' ) ) {
3712                         return array( 'cant-move-subpages' );
3713                 }
3714                 // Do the source and target namespaces support subpages?
3715                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3716                         return array( 'namespace-nosubpages',
3717                                 MWNamespace::getCanonicalName( $this->getNamespace() ) );
3718                 }
3719                 if ( !MWNamespace::hasSubpages( $nt->getNamespace() ) ) {
3720                         return array( 'namespace-nosubpages',
3721                                 MWNamespace::getCanonicalName( $nt->getNamespace() ) );
3722                 }
3723
3724                 $subpages = $this->getSubpages( $wgMaximumMovedPages + 1 );
3725                 $retval = array();
3726                 $count = 0;
3727                 foreach ( $subpages as $oldSubpage ) {
3728                         $count++;
3729                         if ( $count > $wgMaximumMovedPages ) {
3730                                 $retval[$oldSubpage->getPrefixedText()] =
3731                                                 array( 'movepage-max-pages',
3732                                                         $wgMaximumMovedPages );
3733                                 break;
3734                         }
3735
3736                         // We don't know whether this function was called before
3737                         // or after moving the root page, so check both
3738                         // $this and $nt
3739                         if ( $oldSubpage->getArticleID() == $this->getArticleID()
3740                                 || $oldSubpage->getArticleID() == $nt->getArticleID()
3741                         ) {
3742                                 // When moving a page to a subpage of itself,
3743                                 // don't move it twice
3744                                 continue;
3745                         }
3746                         $newPageName = preg_replace(
3747                                         '#^' . preg_quote( $this->getDBkey(), '#' ) . '#',
3748                                         StringUtils::escapeRegexReplacement( $nt->getDBkey() ), # bug 21234
3749                                         $oldSubpage->getDBkey() );
3750                         if ( $oldSubpage->isTalkPage() ) {
3751                                 $newNs = $nt->getTalkPage()->getNamespace();
3752                         } else {
3753                                 $newNs = $nt->getSubjectPage()->getNamespace();
3754                         }
3755                         # Bug 14385: we need makeTitleSafe because the new page names may
3756                         # be longer than 255 characters.
3757                         $newSubpage = Title::makeTitleSafe( $newNs, $newPageName );
3758
3759                         $success = $oldSubpage->moveTo( $newSubpage, $auth, $reason, $createRedirect );
3760                         if ( $success === true ) {
3761                                 $retval[$oldSubpage->getPrefixedText()] = $newSubpage->getPrefixedText();
3762                         } else {
3763                                 $retval[$oldSubpage->getPrefixedText()] = $success;
3764                         }
3765                 }
3766                 return $retval;
3767         }
3768
3769         /**
3770          * Checks if this page is just a one-rev redirect.
3771          * Adds lock, so don't use just for light purposes.
3772          *
3773          * @return bool
3774          */
3775         public function isSingleRevRedirect() {
3776                 global $wgContentHandlerUseDB;
3777
3778                 $dbw = wfGetDB( DB_MASTER );
3779
3780                 # Is it a redirect?
3781                 $fields = array( 'page_is_redirect', 'page_latest', 'page_id' );
3782                 if ( $wgContentHandlerUseDB ) {
3783                         $fields[] = 'page_content_model';
3784                 }
3785
3786                 $row = $dbw->selectRow( 'page',
3787                         $fields,
3788                         $this->pageCond(),
3789                         __METHOD__,
3790                         array( 'FOR UPDATE' )
3791                 );
3792                 # Cache some fields we may want
3793                 $this->mArticleID = $row ? intval( $row->page_id ) : 0;
3794                 $this->mRedirect = $row ? (bool)$row->page_is_redirect : false;
3795                 $this->mLatestID = $row ? intval( $row->page_latest ) : false;
3796                 $this->mContentModel = $row && isset( $row->page_content_model )
3797                         ? strval( $row->page_content_model )
3798                         : false;
3799
3800                 if ( !$this->mRedirect ) {
3801                         return false;
3802                 }
3803                 # Does the article have a history?
3804                 $row = $dbw->selectField( array( 'page', 'revision' ),
3805                         'rev_id',
3806                         array( 'page_namespace' => $this->getNamespace(),
3807                                 'page_title' => $this->getDBkey(),
3808                                 'page_id=rev_page',
3809                                 'page_latest != rev_id'
3810                         ),
3811                         __METHOD__,
3812                         array( 'FOR UPDATE' )
3813                 );
3814                 # Return true if there was no history
3815                 return ( $row === false );
3816         }
3817
3818         /**
3819          * Checks if $this can be moved to a given Title
3820          * - Selects for update, so don't call it unless you mean business
3821          *
3822          * @deprecated since 1.25, use MovePage's methods instead
3823          * @param Title $nt The new title to check
3824          * @return bool
3825          */
3826         public function isValidMoveTarget( $nt ) {
3827                 # Is it an existing file?
3828                 if ( $nt->getNamespace() == NS_FILE ) {
3829                         $file = wfLocalFile( $nt );
3830                         $file->load( File::READ_LATEST );
3831                         if ( $file->exists() ) {
3832                                 wfDebug( __METHOD__ . ": file exists\n" );
3833                                 return false;
3834                         }
3835                 }
3836                 # Is it a redirect with no history?
3837                 if ( !$nt->isSingleRevRedirect() ) {
3838                         wfDebug( __METHOD__ . ": not a one-rev redirect\n" );
3839                         return false;
3840                 }
3841                 # Get the article text
3842                 $rev = Revision::newFromTitle( $nt, false, Revision::READ_LATEST );
3843                 if ( !is_object( $rev ) ) {
3844                         return false;
3845                 }
3846                 $content = $rev->getContent();
3847                 # Does the redirect point to the source?
3848                 # Or is it a broken self-redirect, usually caused by namespace collisions?
3849                 $redirTitle = $content ? $content->getRedirectTarget() : null;
3850
3851                 if ( $redirTitle ) {
3852                         if ( $redirTitle->getPrefixedDBkey() != $this->getPrefixedDBkey() &&
3853                                 $redirTitle->getPrefixedDBkey() != $nt->getPrefixedDBkey() ) {
3854                                 wfDebug( __METHOD__ . ": redirect points to other page\n" );
3855                                 return false;
3856                         } else {
3857                                 return true;
3858                         }
3859                 } else {
3860                         # Fail safe (not a redirect after all. strange.)
3861                         wfDebug( __METHOD__ . ": failsafe: database sais " . $nt->getPrefixedDBkey() .
3862                                                 " is a redirect, but it doesn't contain a valid redirect.\n" );
3863                         return false;
3864                 }
3865         }
3866
3867         /**
3868          * Get categories to which this Title belongs and return an array of
3869          * categories' names.
3870          *
3871          * @return array Array of parents in the form:
3872          *        $parent => $currentarticle
3873          */
3874         public function getParentCategories() {
3875                 global $wgContLang;
3876
3877                 $data = array();
3878
3879                 $titleKey = $this->getArticleID();
3880
3881                 if ( $titleKey === 0 ) {
3882                         return $data;
3883                 }
3884
3885                 $dbr = wfGetDB( DB_SLAVE );
3886
3887                 $res = $dbr->select(
3888                         'categorylinks',
3889                         'cl_to',
3890                         array( 'cl_from' => $titleKey ),
3891                         __METHOD__
3892                 );
3893
3894                 if ( $res->numRows() > 0 ) {
3895                         foreach ( $res as $row ) {
3896                                 // $data[] = Title::newFromText($wgContLang->getNsText ( NS_CATEGORY ).':'.$row->cl_to);
3897                                 $data[$wgContLang->getNsText( NS_CATEGORY ) . ':' . $row->cl_to] = $this->getFullText();
3898                         }
3899                 }
3900                 return $data;
3901         }
3902
3903         /**
3904          * Get a tree of parent categories
3905          *
3906          * @param array $children Array with the children in the keys, to check for circular refs
3907          * @return array Tree of parent categories
3908          */
3909         public function getParentCategoryTree( $children = array() ) {
3910                 $stack = array();
3911                 $parents = $this->getParentCategories();
3912
3913                 if ( $parents ) {
3914                         foreach ( $parents as $parent => $current ) {
3915                                 if ( array_key_exists( $parent, $children ) ) {
3916                                         # Circular reference
3917                                         $stack[$parent] = array();
3918                                 } else {
3919                                         $nt = Title::newFromText( $parent );
3920                                         if ( $nt ) {
3921                                                 $stack[$parent] = $nt->getParentCategoryTree( $children + array( $parent => 1 ) );
3922                                         }
3923                                 }
3924                         }
3925                 }
3926
3927                 return $stack;
3928         }
3929
3930         /**
3931          * Get an associative array for selecting this title from
3932          * the "page" table
3933          *
3934          * @return array Array suitable for the $where parameter of DB::select()
3935          */
3936         public function pageCond() {
3937                 if ( $this->mArticleID > 0 ) {
3938                         // PK avoids secondary lookups in InnoDB, shouldn't hurt other DBs
3939                         return array( 'page_id' => $this->mArticleID );
3940                 } else {
3941                         return array( 'page_namespace' => $this->mNamespace, 'page_title' => $this->mDbkeyform );
3942                 }
3943         }
3944
3945         /**
3946          * Get the revision ID of the previous revision
3947          *
3948          * @param int $revId Revision ID. Get the revision that was before this one.
3949          * @param int $flags Title::GAID_FOR_UPDATE
3950          * @return int|bool Old revision ID, or false if none exists
3951          */
3952         public function getPreviousRevisionID( $revId, $flags = 0 ) {
3953                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
3954                 $revId = $db->selectField( 'revision', 'rev_id',
3955                         array(
3956                                 'rev_page' => $this->getArticleID( $flags ),
3957                                 'rev_id < ' . intval( $revId )
3958                         ),
3959                         __METHOD__,
3960                         array( 'ORDER BY' => 'rev_id DESC' )
3961                 );
3962
3963                 if ( $revId === false ) {
3964                         return false;
3965                 } else {
3966                         return intval( $revId );
3967                 }
3968         }
3969
3970         /**
3971          * Get the revision ID of the next revision
3972          *
3973          * @param int $revId Revision ID. Get the revision that was after this one.
3974          * @param int $flags Title::GAID_FOR_UPDATE
3975          * @return int|bool Next revision ID, or false if none exists
3976          */
3977         public function getNextRevisionID( $revId, $flags = 0 ) {
3978                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
3979                 $revId = $db->selectField( 'revision', 'rev_id',
3980                         array(
3981                                 'rev_page' => $this->getArticleID( $flags ),
3982                                 'rev_id > ' . intval( $revId )
3983                         ),
3984                         __METHOD__,
3985                         array( 'ORDER BY' => 'rev_id' )
3986                 );
3987
3988                 if ( $revId === false ) {
3989                         return false;
3990                 } else {
3991                         return intval( $revId );
3992                 }
3993         }
3994
3995         /**
3996          * Get the first revision of the page
3997          *
3998          * @param int $flags Title::GAID_FOR_UPDATE
3999          * @return Revision|null If page doesn't exist
4000          */
4001         public function getFirstRevision( $flags = 0 ) {
4002                 $pageId = $this->getArticleID( $flags );
4003                 if ( $pageId ) {
4004                         $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
4005                         $row = $db->selectRow( 'revision', Revision::selectFields(),
4006                                 array( 'rev_page' => $pageId ),
4007                                 __METHOD__,
4008                                 array( 'ORDER BY' => 'rev_timestamp ASC', 'LIMIT' => 1 )
4009                         );
4010                         if ( $row ) {
4011                                 return new Revision( $row );
4012                         }
4013                 }
4014                 return null;
4015         }
4016
4017         /**
4018          * Get the oldest revision timestamp of this page
4019          *
4020          * @param int $flags Title::GAID_FOR_UPDATE
4021          * @return string MW timestamp
4022          */
4023         public function getEarliestRevTime( $flags = 0 ) {
4024                 $rev = $this->getFirstRevision( $flags );
4025                 return $rev ? $rev->getTimestamp() : null;
4026         }
4027
4028         /**
4029          * Check if this is a new page
4030          *
4031          * @return bool
4032          */
4033         public function isNewPage() {
4034                 $dbr = wfGetDB( DB_SLAVE );
4035                 return (bool)$dbr->selectField( 'page', 'page_is_new', $this->pageCond(), __METHOD__ );
4036         }
4037
4038         /**
4039          * Check whether the number of revisions of this page surpasses $wgDeleteRevisionsLimit
4040          *
4041          * @return bool
4042          */
4043         public function isBigDeletion() {
4044                 global $wgDeleteRevisionsLimit;
4045
4046                 if ( !$wgDeleteRevisionsLimit ) {
4047                         return false;
4048                 }
4049
4050                 if ( $this->mIsBigDeletion === null ) {
4051                         $dbr = wfGetDB( DB_SLAVE );
4052
4053                         $revCount = $dbr->selectRowCount(
4054                                 'revision',
4055                                 '1',
4056                                 array( 'rev_page' => $this->getArticleID() ),
4057                                 __METHOD__,
4058                                 array( 'LIMIT' => $wgDeleteRevisionsLimit + 1 )
4059                         );
4060
4061                         $this->mIsBigDeletion = $revCount > $wgDeleteRevisionsLimit;
4062                 }
4063
4064                 return $this->mIsBigDeletion;
4065         }
4066
4067         /**
4068          * Get the approximate revision count of this page.
4069          *
4070          * @return int
4071          */
4072         public function estimateRevisionCount() {
4073                 if ( !$this->exists() ) {
4074                         return 0;
4075                 }
4076
4077                 if ( $this->mEstimateRevisions === null ) {
4078                         $dbr = wfGetDB( DB_SLAVE );
4079                         $this->mEstimateRevisions = $dbr->estimateRowCount( 'revision', '*',
4080                                 array( 'rev_page' => $this->getArticleID() ), __METHOD__ );
4081                 }
4082
4083                 return $this->mEstimateRevisions;
4084         }
4085
4086         /**
4087          * Get the number of revisions between the given revision.
4088          * Used for diffs and other things that really need it.
4089          *
4090          * @param int|Revision $old Old revision or rev ID (first before range)
4091          * @param int|Revision $new New revision or rev ID (first after range)
4092          * @param int|null $max Limit of Revisions to count, will be incremented to detect truncations
4093          * @return int Number of revisions between these revisions.
4094          */
4095         public function countRevisionsBetween( $old, $new, $max = null ) {
4096                 if ( !( $old instanceof Revision ) ) {
4097                         $old = Revision::newFromTitle( $this, (int)$old );
4098                 }
4099                 if ( !( $new instanceof Revision ) ) {
4100                         $new = Revision::newFromTitle( $this, (int)$new );
4101                 }
4102                 if ( !$old || !$new ) {
4103                         return 0; // nothing to compare
4104                 }
4105                 $dbr = wfGetDB( DB_SLAVE );
4106                 $conds = array(
4107                         'rev_page' => $this->getArticleID(),
4108                         'rev_timestamp > ' . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4109                         'rev_timestamp < ' . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4110                 );
4111                 if ( $max !== null ) {
4112                         return $dbr->selectRowCount( 'revision', '1',
4113                                 $conds,
4114                                 __METHOD__,
4115                                 array( 'LIMIT' => $max + 1 ) // extra to detect truncation
4116                         );
4117                 } else {
4118                         return (int)$dbr->selectField( 'revision', 'count(*)', $conds, __METHOD__ );
4119                 }
4120         }
4121
4122         /**
4123          * Get the authors between the given revisions or revision IDs.
4124          * Used for diffs and other things that really need it.
4125          *
4126          * @since 1.23
4127          *
4128          * @param int|Revision $old Old revision or rev ID (first before range by default)
4129          * @param int|Revision $new New revision or rev ID (first after range by default)
4130          * @param int $limit Maximum number of authors
4131          * @param string|array $options (Optional): Single option, or an array of options:
4132          *     'include_old' Include $old in the range; $new is excluded.
4133          *     'include_new' Include $new in the range; $old is excluded.
4134          *     'include_both' Include both $old and $new in the range.
4135          *     Unknown option values are ignored.
4136          * @return array|null Names of revision authors in the range; null if not both revisions exist
4137          */
4138         public function getAuthorsBetween( $old, $new, $limit, $options = array() ) {
4139                 if ( !( $old instanceof Revision ) ) {
4140                         $old = Revision::newFromTitle( $this, (int)$old );
4141                 }
4142                 if ( !( $new instanceof Revision ) ) {
4143                         $new = Revision::newFromTitle( $this, (int)$new );
4144                 }
4145                 // XXX: what if Revision objects are passed in, but they don't refer to this title?
4146                 // Add $old->getPage() != $new->getPage() || $old->getPage() != $this->getArticleID()
4147                 // in the sanity check below?
4148                 if ( !$old || !$new ) {
4149                         return null; // nothing to compare
4150                 }
4151                 $authors = array();
4152                 $old_cmp = '>';
4153                 $new_cmp = '<';
4154                 $options = (array)$options;
4155                 if ( in_array( 'include_old', $options ) ) {
4156                         $old_cmp = '>=';
4157                 }
4158                 if ( in_array( 'include_new', $options ) ) {
4159                         $new_cmp = '<=';
4160                 }
4161                 if ( in_array( 'include_both', $options ) ) {
4162                         $old_cmp = '>=';
4163                         $new_cmp = '<=';
4164                 }
4165                 // No DB query needed if $old and $new are the same or successive revisions:
4166                 if ( $old->getId() === $new->getId() ) {
4167                         return ( $old_cmp === '>' && $new_cmp === '<' ) ?
4168                                 array() :
4169                                 array( $old->getUserText( Revision::RAW ) );
4170                 } elseif ( $old->getId() === $new->getParentId() ) {
4171                         if ( $old_cmp === '>=' && $new_cmp === '<=' ) {
4172                                 $authors[] = $old->getUserText( Revision::RAW );
4173                                 if ( $old->getUserText( Revision::RAW ) != $new->getUserText( Revision::RAW ) ) {
4174                                         $authors[] = $new->getUserText( Revision::RAW );
4175                                 }
4176                         } elseif ( $old_cmp === '>=' ) {
4177                                 $authors[] = $old->getUserText( Revision::RAW );
4178                         } elseif ( $new_cmp === '<=' ) {
4179                                 $authors[] = $new->getUserText( Revision::RAW );
4180                         }
4181                         return $authors;
4182                 }
4183                 $dbr = wfGetDB( DB_SLAVE );
4184                 $res = $dbr->select( 'revision', 'DISTINCT rev_user_text',
4185                         array(
4186                                 'rev_page' => $this->getArticleID(),
4187                                 "rev_timestamp $old_cmp " . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4188                                 "rev_timestamp $new_cmp " . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4189                         ), __METHOD__,
4190                         array( 'LIMIT' => $limit + 1 ) // add one so caller knows it was truncated
4191                 );
4192                 foreach ( $res as $row ) {
4193                         $authors[] = $row->rev_user_text;
4194                 }
4195                 return $authors;
4196         }
4197
4198         /**
4199          * Get the number of authors between the given revisions or revision IDs.
4200          * Used for diffs and other things that really need it.
4201          *
4202          * @param int|Revision $old Old revision or rev ID (first before range by default)
4203          * @param int|Revision $new New revision or rev ID (first after range by default)
4204          * @param int $limit Maximum number of authors
4205          * @param string|array $options (Optional): Single option, or an array of options:
4206          *     'include_old' Include $old in the range; $new is excluded.
4207          *     'include_new' Include $new in the range; $old is excluded.
4208          *     'include_both' Include both $old and $new in the range.
4209          *     Unknown option values are ignored.
4210          * @return int Number of revision authors in the range; zero if not both revisions exist
4211          */
4212         public function countAuthorsBetween( $old, $new, $limit, $options = array() ) {
4213                 $authors = $this->getAuthorsBetween( $old, $new, $limit, $options );
4214                 return $authors ? count( $authors ) : 0;
4215         }
4216
4217         /**
4218          * Compare with another title.
4219          *
4220          * @param Title $title
4221          * @return bool
4222          */
4223         public function equals( Title $title ) {
4224                 // Note: === is necessary for proper matching of number-like titles.
4225                 return $this->getInterwiki() === $title->getInterwiki()
4226                         && $this->getNamespace() == $title->getNamespace()
4227                         && $this->getDBkey() === $title->getDBkey();
4228         }
4229
4230         /**
4231          * Check if this title is a subpage of another title
4232          *
4233          * @param Title $title
4234          * @return bool
4235          */
4236         public function isSubpageOf( Title $title ) {
4237                 return $this->getInterwiki() === $title->getInterwiki()
4238                         && $this->getNamespace() == $title->getNamespace()
4239                         && strpos( $this->getDBkey(), $title->getDBkey() . '/' ) === 0;
4240         }
4241
4242         /**
4243          * Check if page exists.  For historical reasons, this function simply
4244          * checks for the existence of the title in the page table, and will
4245          * thus return false for interwiki links, special pages and the like.
4246          * If you want to know if a title can be meaningfully viewed, you should
4247          * probably call the isKnown() method instead.
4248          *
4249          * @param int $flags An optional bit field; may be Title::GAID_FOR_UPDATE to check
4250          *   from master/for update
4251          * @return bool
4252          */
4253         public function exists( $flags = 0 ) {
4254                 $exists = $this->getArticleID( $flags ) != 0;
4255                 Hooks::run( 'TitleExists', array( $this, &$exists ) );
4256                 return $exists;
4257         }
4258
4259         /**
4260          * Should links to this title be shown as potentially viewable (i.e. as
4261          * "bluelinks"), even if there's no record by this title in the page
4262          * table?
4263          *
4264          * This function is semi-deprecated for public use, as well as somewhat
4265          * misleadingly named.  You probably just want to call isKnown(), which
4266          * calls this function internally.
4267          *
4268          * (ISSUE: Most of these checks are cheap, but the file existence check
4269          * can potentially be quite expensive.  Including it here fixes a lot of
4270          * existing code, but we might want to add an optional parameter to skip
4271          * it and any other expensive checks.)
4272          *
4273          * @return bool
4274          */
4275         public function isAlwaysKnown() {
4276                 $isKnown = null;
4277
4278                 /**
4279                  * Allows overriding default behavior for determining if a page exists.
4280                  * If $isKnown is kept as null, regular checks happen. If it's
4281                  * a boolean, this value is returned by the isKnown method.
4282                  *
4283                  * @since 1.20
4284                  *
4285                  * @param Title $title
4286                  * @param bool|null $isKnown
4287                  */
4288                 Hooks::run( 'TitleIsAlwaysKnown', array( $this, &$isKnown ) );
4289
4290                 if ( !is_null( $isKnown ) ) {
4291                         return $isKnown;
4292                 }
4293
4294                 if ( $this->isExternal() ) {
4295                         return true;  // any interwiki link might be viewable, for all we know
4296                 }
4297
4298                 switch ( $this->mNamespace ) {
4299                         case NS_MEDIA:
4300                         case NS_FILE:
4301                                 // file exists, possibly in a foreign repo
4302                                 return (bool)wfFindFile( $this );
4303                         case NS_SPECIAL:
4304                                 // valid special page
4305                                 return SpecialPageFactory::exists( $this->getDBkey() );
4306                         case NS_MAIN:
4307                                 // selflink, possibly with fragment
4308                                 return $this->mDbkeyform == '';
4309                         case NS_MEDIAWIKI:
4310                                 // known system message
4311                                 return $this->hasSourceText() !== false;
4312                         default:
4313                                 return false;
4314                 }
4315         }
4316
4317         /**
4318          * Does this title refer to a page that can (or might) be meaningfully
4319          * viewed?  In particular, this function may be used to determine if
4320          * links to the title should be rendered as "bluelinks" (as opposed to
4321          * "redlinks" to non-existent pages).
4322          * Adding something else to this function will cause inconsistency
4323          * since LinkHolderArray calls isAlwaysKnown() and does its own
4324          * page existence check.
4325          *
4326          * @return bool
4327          */
4328         public function isKnown() {
4329                 return $this->isAlwaysKnown() || $this->exists();
4330         }
4331
4332         /**
4333          * Does this page have source text?
4334          *
4335          * @return bool
4336          */
4337         public function hasSourceText() {
4338                 if ( $this->exists() ) {
4339                         return true;
4340                 }
4341
4342                 if ( $this->mNamespace == NS_MEDIAWIKI ) {
4343                         // If the page doesn't exist but is a known system message, default
4344                         // message content will be displayed, same for language subpages-
4345                         // Use always content language to avoid loading hundreds of languages
4346                         // to get the link color.
4347                         global $wgContLang;
4348                         list( $name, ) = MessageCache::singleton()->figureMessage(
4349                                 $wgContLang->lcfirst( $this->getText() )
4350                         );
4351                         $message = wfMessage( $name )->inLanguage( $wgContLang )->useDatabase( false );
4352                         return $message->exists();
4353                 }
4354
4355                 return false;
4356         }
4357
4358         /**
4359          * Get the default message text or false if the message doesn't exist
4360          *
4361          * @return string|bool
4362          */
4363         public function getDefaultMessageText() {
4364                 global $wgContLang;
4365
4366                 if ( $this->getNamespace() != NS_MEDIAWIKI ) { // Just in case
4367                         return false;
4368                 }
4369
4370                 list( $name, $lang ) = MessageCache::singleton()->figureMessage(
4371                         $wgContLang->lcfirst( $this->getText() )
4372                 );
4373                 $message = wfMessage( $name )->inLanguage( $lang )->useDatabase( false );
4374
4375                 if ( $message->exists() ) {
4376                         return $message->plain();
4377                 } else {
4378                         return false;
4379                 }
4380         }
4381
4382         /**
4383          * Updates page_touched for this page; called from LinksUpdate.php
4384          *
4385          * @param string $purgeTime [optional] TS_MW timestamp
4386          * @return bool True if the update succeeded
4387          */
4388         public function invalidateCache( $purgeTime = null ) {
4389                 if ( wfReadOnly() ) {
4390                         return false;
4391                 }
4392
4393                 if ( $this->mArticleID === 0 ) {
4394                         return true; // avoid gap locking if we know it's not there
4395                 }
4396
4397                 $method = __METHOD__;
4398                 $dbw = wfGetDB( DB_MASTER );
4399                 $conds = $this->pageCond();
4400                 $dbw->onTransactionIdle( function () use ( $dbw, $conds, $method, $purgeTime ) {
4401                         $dbTimestamp = $dbw->timestamp( $purgeTime ?: time() );
4402
4403                         $dbw->update(
4404                                 'page',
4405                                 array( 'page_touched' => $dbTimestamp ),
4406                                 $conds + array( 'page_touched < ' . $dbw->addQuotes( $dbTimestamp ) ),
4407                                 $method
4408                         );
4409                 } );
4410
4411                 return true;
4412         }
4413
4414         /**
4415          * Update page_touched timestamps and send squid purge messages for
4416          * pages linking to this title. May be sent to the job queue depending
4417          * on the number of links. Typically called on create and delete.
4418          */
4419         public function touchLinks() {
4420                 DeferredUpdates::addUpdate( new HTMLCacheUpdate( $this, 'pagelinks' ) );
4421                 if ( $this->getNamespace() == NS_CATEGORY ) {
4422                         DeferredUpdates::addUpdate( new HTMLCacheUpdate( $this, 'categorylinks' ) );
4423                 }
4424         }
4425
4426         /**
4427          * Get the last touched timestamp
4428          *
4429          * @param IDatabase $db Optional db
4430          * @return string Last-touched timestamp
4431          */
4432         public function getTouched( $db = null ) {
4433                 if ( $db === null ) {
4434                         $db = wfGetDB( DB_SLAVE );
4435                 }
4436                 $touched = $db->selectField( 'page', 'page_touched', $this->pageCond(), __METHOD__ );
4437                 return $touched;
4438         }
4439
4440         /**
4441          * Get the timestamp when this page was updated since the user last saw it.
4442          *
4443          * @param User $user
4444          * @return string|null
4445          */
4446         public function getNotificationTimestamp( $user = null ) {
4447                 global $wgUser;
4448
4449                 // Assume current user if none given
4450                 if ( !$user ) {
4451                         $user = $wgUser;
4452                 }
4453                 // Check cache first
4454                 $uid = $user->getId();
4455                 if ( !$uid ) {
4456                         return false;
4457                 }
4458                 // avoid isset here, as it'll return false for null entries
4459                 if ( array_key_exists( $uid, $this->mNotificationTimestamp ) ) {
4460                         return $this->mNotificationTimestamp[$uid];
4461                 }
4462                 // Don't cache too much!
4463                 if ( count( $this->mNotificationTimestamp ) >= self::CACHE_MAX ) {
4464                         $this->mNotificationTimestamp = array();
4465                 }
4466
4467                 $watchedItem = WatchedItem::fromUserTitle( $user, $this );
4468                 $this->mNotificationTimestamp[$uid] = $watchedItem->getNotificationTimestamp();
4469
4470                 return $this->mNotificationTimestamp[$uid];
4471         }
4472
4473         /**
4474          * Generate strings used for xml 'id' names in monobook tabs
4475          *
4476          * @param string $prepend Defaults to 'nstab-'
4477          * @return string XML 'id' name
4478          */
4479         public function getNamespaceKey( $prepend = 'nstab-' ) {
4480                 global $wgContLang;
4481                 // Gets the subject namespace if this title
4482                 $namespace = MWNamespace::getSubject( $this->getNamespace() );
4483                 // Checks if canonical namespace name exists for namespace
4484                 if ( MWNamespace::exists( $this->getNamespace() ) ) {
4485                         // Uses canonical namespace name
4486                         $namespaceKey = MWNamespace::getCanonicalName( $namespace );
4487                 } else {
4488                         // Uses text of namespace
4489                         $namespaceKey = $this->getSubjectNsText();
4490                 }
4491                 // Makes namespace key lowercase
4492                 $namespaceKey = $wgContLang->lc( $namespaceKey );
4493                 // Uses main
4494                 if ( $namespaceKey == '' ) {
4495                         $namespaceKey = 'main';
4496                 }
4497                 // Changes file to image for backwards compatibility
4498                 if ( $namespaceKey == 'file' ) {
4499                         $namespaceKey = 'image';
4500                 }
4501                 return $prepend . $namespaceKey;
4502         }
4503
4504         /**
4505          * Get all extant redirects to this Title
4506          *
4507          * @param int|null $ns Single namespace to consider; null to consider all namespaces
4508          * @return Title[] Array of Title redirects to this title
4509          */
4510         public function getRedirectsHere( $ns = null ) {
4511                 $redirs = array();
4512
4513                 $dbr = wfGetDB( DB_SLAVE );
4514                 $where = array(
4515                         'rd_namespace' => $this->getNamespace(),
4516                         'rd_title' => $this->getDBkey(),
4517                         'rd_from = page_id'
4518                 );
4519                 if ( $this->isExternal() ) {
4520                         $where['rd_interwiki'] = $this->getInterwiki();
4521                 } else {
4522                         $where[] = 'rd_interwiki = ' . $dbr->addQuotes( '' ) . ' OR rd_interwiki IS NULL';
4523                 }
4524                 if ( !is_null( $ns ) ) {
4525                         $where['page_namespace'] = $ns;
4526                 }
4527
4528                 $res = $dbr->select(
4529                         array( 'redirect', 'page' ),
4530                         array( 'page_namespace', 'page_title' ),
4531                         $where,
4532                         __METHOD__
4533                 );
4534
4535                 foreach ( $res as $row ) {
4536                         $redirs[] = self::newFromRow( $row );
4537                 }
4538                 return $redirs;
4539         }
4540
4541         /**
4542          * Check if this Title is a valid redirect target
4543          *
4544          * @return bool
4545          */
4546         public function isValidRedirectTarget() {
4547                 global $wgInvalidRedirectTargets;
4548
4549                 if ( $this->isSpecialPage() ) {
4550                         // invalid redirect targets are stored in a global array, but explicitly disallow Userlogout here
4551                         if ( $this->isSpecial( 'Userlogout' ) ) {
4552                                 return false;
4553                         }
4554
4555                         foreach ( $wgInvalidRedirectTargets as $target ) {
4556                                 if ( $this->isSpecial( $target ) ) {
4557                                         return false;
4558                                 }
4559                         }
4560                 }
4561
4562                 return true;
4563         }
4564
4565         /**
4566          * Get a backlink cache object
4567          *
4568          * @return BacklinkCache
4569          */
4570         public function getBacklinkCache() {
4571                 return BacklinkCache::get( $this );
4572         }
4573
4574         /**
4575          * Whether the magic words __INDEX__ and __NOINDEX__ function for  this page.
4576          *
4577          * @return bool
4578          */
4579         public function canUseNoindex() {
4580                 global $wgContentNamespaces, $wgExemptFromUserRobotsControl;
4581
4582                 $bannedNamespaces = is_null( $wgExemptFromUserRobotsControl )
4583                         ? $wgContentNamespaces
4584                         : $wgExemptFromUserRobotsControl;
4585
4586                 return !in_array( $this->mNamespace, $bannedNamespaces );
4587
4588         }
4589
4590         /**
4591          * Returns the raw sort key to be used for categories, with the specified
4592          * prefix.  This will be fed to Collation::getSortKey() to get a
4593          * binary sortkey that can be used for actual sorting.
4594          *
4595          * @param string $prefix The prefix to be used, specified using
4596          *   {{defaultsort:}} or like [[Category:Foo|prefix]].  Empty for no
4597          *   prefix.
4598          * @return string
4599          */
4600         public function getCategorySortkey( $prefix = '' ) {
4601                 $unprefixed = $this->getText();
4602
4603                 // Anything that uses this hook should only depend
4604                 // on the Title object passed in, and should probably
4605                 // tell the users to run updateCollations.php --force
4606                 // in order to re-sort existing category relations.
4607                 Hooks::run( 'GetDefaultSortkey', array( $this, &$unprefixed ) );
4608                 if ( $prefix !== '' ) {
4609                         # Separate with a line feed, so the unprefixed part is only used as
4610                         # a tiebreaker when two pages have the exact same prefix.
4611                         # In UCA, tab is the only character that can sort above LF
4612                         # so we strip both of them from the original prefix.
4613                         $prefix = strtr( $prefix, "\n\t", '  ' );
4614                         return "$prefix\n$unprefixed";
4615                 }
4616                 return $unprefixed;
4617         }
4618
4619         /**
4620          * Get the language in which the content of this page is written in
4621          * wikitext. Defaults to $wgContLang, but in certain cases it can be
4622          * e.g. $wgLang (such as special pages, which are in the user language).
4623          *
4624          * @since 1.18
4625          * @return Language
4626          */
4627         public function getPageLanguage() {
4628                 global $wgLang, $wgLanguageCode;
4629                 if ( $this->isSpecialPage() ) {
4630                         // special pages are in the user language
4631                         return $wgLang;
4632                 }
4633
4634                 // Checking if DB language is set
4635                 if ( $this->mDbPageLanguage ) {
4636                         return wfGetLangObj( $this->mDbPageLanguage );
4637                 }
4638
4639                 if ( !$this->mPageLanguage || $this->mPageLanguage[1] !== $wgLanguageCode ) {
4640                         // Note that this may depend on user settings, so the cache should
4641                         // be only per-request.
4642                         // NOTE: ContentHandler::getPageLanguage() may need to load the
4643                         // content to determine the page language!
4644                         // Checking $wgLanguageCode hasn't changed for the benefit of unit
4645                         // tests.
4646                         $contentHandler = ContentHandler::getForTitle( $this );
4647                         $langObj = wfGetLangObj( $contentHandler->getPageLanguage( $this ) );
4648                         $this->mPageLanguage = array( $langObj->getCode(), $wgLanguageCode );
4649                 } else {
4650                         $langObj = wfGetLangObj( $this->mPageLanguage[0] );
4651                 }
4652
4653                 return $langObj;
4654         }
4655
4656         /**
4657          * Get the language in which the content of this page is written when
4658          * viewed by user. Defaults to $wgContLang, but in certain cases it can be
4659          * e.g. $wgLang (such as special pages, which are in the user language).
4660          *
4661          * @since 1.20
4662          * @return Language
4663          */
4664         public function getPageViewLanguage() {
4665                 global $wgLang;
4666
4667                 if ( $this->isSpecialPage() ) {
4668                         // If the user chooses a variant, the content is actually
4669                         // in a language whose code is the variant code.
4670                         $variant = $wgLang->getPreferredVariant();
4671                         if ( $wgLang->getCode() !== $variant ) {
4672                                 return Language::factory( $variant );
4673                         }
4674
4675                         return $wgLang;
4676                 }
4677
4678                 // @note Can't be cached persistently, depends on user settings.
4679                 // @note ContentHandler::getPageViewLanguage() may need to load the
4680                 //   content to determine the page language!
4681                 $contentHandler = ContentHandler::getForTitle( $this );
4682                 $pageLang = $contentHandler->getPageViewLanguage( $this );
4683                 return $pageLang;
4684         }
4685
4686         /**
4687          * Get a list of rendered edit notices for this page.
4688          *
4689          * Array is keyed by the original message key, and values are rendered using parseAsBlock, so
4690          * they will already be wrapped in paragraphs.
4691          *
4692          * @since 1.21
4693          * @param int $oldid Revision ID that's being edited
4694          * @return array
4695          */
4696         public function getEditNotices( $oldid = 0 ) {
4697                 $notices = array();
4698
4699                 // Optional notice for the entire namespace
4700                 $editnotice_ns = 'editnotice-' . $this->getNamespace();
4701                 $msg = wfMessage( $editnotice_ns );
4702                 if ( $msg->exists() ) {
4703                         $html = $msg->parseAsBlock();
4704                         // Edit notices may have complex logic, but output nothing (T91715)
4705                         if ( trim( $html ) !== '' ) {
4706                                 $notices[$editnotice_ns] = Html::rawElement(
4707                                         'div',
4708                                         array( 'class' => array(
4709                                                 'mw-editnotice',
4710                                                 'mw-editnotice-namespace',
4711                                                 Sanitizer::escapeClass( "mw-$editnotice_ns" )
4712                                         ) ),
4713                                         $html
4714                                 );
4715                         }
4716                 }
4717
4718                 if ( MWNamespace::hasSubpages( $this->getNamespace() ) ) {
4719                         // Optional notice for page itself and any parent page
4720                         $parts = explode( '/', $this->getDBkey() );
4721                         $editnotice_base = $editnotice_ns;
4722                         while ( count( $parts ) > 0 ) {
4723                                 $editnotice_base .= '-' . array_shift( $parts );
4724                                 $msg = wfMessage( $editnotice_base );
4725                                 if ( $msg->exists() ) {
4726                                         $html = $msg->parseAsBlock();
4727                                         if ( trim( $html ) !== '' ) {
4728                                                 $notices[$editnotice_base] = Html::rawElement(
4729                                                         'div',
4730                                                         array( 'class' => array(
4731                                                                 'mw-editnotice',
4732                                                                 'mw-editnotice-base',
4733                                                                 Sanitizer::escapeClass( "mw-$editnotice_base" )
4734                                                         ) ),
4735                                                         $html
4736                                                 );
4737                                         }
4738                                 }
4739                         }
4740                 } else {
4741                         // Even if there are no subpages in namespace, we still don't want "/" in MediaWiki message keys
4742                         $editnoticeText = $editnotice_ns . '-' . strtr( $this->getDBkey(), '/', '-' );
4743                         $msg = wfMessage( $editnoticeText );
4744                         if ( $msg->exists() ) {
4745                                 $html = $msg->parseAsBlock();
4746                                 if ( trim( $html ) !== '' ) {
4747                                         $notices[$editnoticeText] = Html::rawElement(
4748                                                 'div',
4749                                                 array( 'class' => array(
4750                                                         'mw-editnotice',
4751                                                         'mw-editnotice-page',
4752                                                         Sanitizer::escapeClass( "mw-$editnoticeText" )
4753                                                 ) ),
4754                                                 $html
4755                                         );
4756                                 }
4757                         }
4758                 }
4759
4760                 Hooks::run( 'TitleGetEditNotices', array( $this, $oldid, &$notices ) );
4761                 return $notices;
4762         }
4763
4764         /**
4765          * @return array
4766          */
4767         public function __sleep() {
4768                 return array(
4769                         'mNamespace',
4770                         'mDbkeyform',
4771                         'mFragment',
4772                         'mInterwiki',
4773                         'mLocalInterwiki',
4774                         'mUserCaseDBKey',
4775                         'mDefaultNamespace',
4776                 );
4777         }
4778
4779         public function __wakeup() {
4780                 $this->mArticleID = ( $this->mNamespace >= 0 ) ? -1 : 0;
4781                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
4782                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
4783         }
4784
4785 }