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  * @internal documentation reviewed 15 Mar 2010
  34  */
  35 class Title {
  36         /** @var MapCacheLRU */
  37         static private $titleCache = null;
  38
  39         /**
  40          * Title::newFromText maintains a cache to avoid expensive re-normalization of
  41          * commonly used titles. On a batch operation this can become a memory leak
  42          * if not bounded. After hitting this many titles reset the cache.
  43          */
  44         const CACHE_MAX = 1000;
  45
  46         /**
  47          * Used to be GAID_FOR_UPDATE define. Used with getArticleID() and friends
  48          * to use the master DB
  49          */
  50         const GAID_FOR_UPDATE = 1;
  51
  52         /**
  53          * @name Private member variables
  54          * Please use the accessor functions instead.
  55          * @private
  56          */
  57         // @{
  58
  59         /** @var string Text form (spaces not underscores) of the main part */
  60         public $mTextform = '';
  61
  62         /** @var string URL-encoded form of the main part */
  63         public $mUrlform = '';
  64
  65         /** @var string Main part with underscores */
  66         public $mDbkeyform = '';
  67
  68         /** @var string Database key with the initial letter in the case specified by the user */
  69         protected $mUserCaseDBKey;
  70
  71         /** @var int Namespace index, i.e. one of the NS_xxxx constants */
  72         public $mNamespace = NS_MAIN;
  73
  74         /** @var string Interwiki prefix */
  75         public $mInterwiki = '';
  76
  77         /** @var bool Was this Title created from a string with a local interwiki prefix? */
  78         private $mLocalInterwiki = false;
  79
  80         /** @var string Title fragment (i.e. the bit after the #) */
  81         public $mFragment = '';
  82
  83         /** @var int Article ID, fetched from the link cache on demand */
  84         public $mArticleID = -1;
  85
  86         /** @var bool|int ID of most recent revision */
  87         protected $mLatestID = false;
  88
  89         /**
  90          * @var bool|string ID of the page's content model, i.e. one of the
  91          *   CONTENT_MODEL_XXX constants
  92          */
  93         public $mContentModel = false;
  94
  95         /** @var int Estimated number of revisions; null of not loaded */
  96         private $mEstimateRevisions;
  97
  98         /** @var array Array of groups allowed to edit this article */
  99         public $mRestrictions = array();
 100
 101         /** @var bool */
 102         protected $mOldRestrictions = false;
 103
 104         /** @var bool Cascade restrictions on this page to included templates and images? */
 105         public $mCascadeRestriction;
 106
 107         /** Caching the results of getCascadeProtectionSources */
 108         public $mCascadingRestrictions;
 109
 110         /** @var array When do the restrictions on this page expire? */
 111         protected $mRestrictionsExpiry = array();
 112
 113         /** @var bool Are cascading restrictions in effect on this page? */
 114         protected $mHasCascadingRestrictions;
 115
 116         /** @var array Where are the cascading restrictions coming from on this page? */
 117         public $mCascadeSources;
 118
 119         /** @var bool Boolean for initialisation on demand */
 120         public $mRestrictionsLoaded = false;
 121
 122         /** @var string Text form including namespace/interwiki, initialised on demand */
 123         protected $mPrefixedText = null;
 124
 125         /** @var mixed Cached value for getTitleProtection (create protection) */
 126         public $mTitleProtection;
 127
 128         /**
 129          * @var int Namespace index when there is no namespace. Don't change the
 130          *   following default, NS_MAIN is hardcoded in several places. See bug 696.
 131          *   Zero except in {{transclusion}} tags.
 132          */
 133         public $mDefaultNamespace = NS_MAIN;
 134
 135         /**
 136          * @var bool Is $wgUser watching this page? null if unfilled, accessed
 137          * through userIsWatching()
 138          */
 139         protected $mWatched = null;
 140
 141         /** @var int The page length, 0 for special pages */
 142         protected $mLength = -1;
 143
 144         /** @var null Is the article at this title a redirect? */
 145         public $mRedirect = null;
 146
 147         /** @var array Associative array of user ID -> timestamp/false */
 148         private $mNotificationTimestamp = array();
 149
 150         /** @var bool Whether a page has any subpages */
 151         private $mHasSubpages;
 152
 153         /** @var bool The (string) language code of the page's language and content code. */
 154         private $mPageLanguage = false;
 155
 156         /** @var string The page language code from the database */
 157         private $mDbPageLanguage = null;
 158
 159         /** @var TitleValue A corresponding TitleValue object */
 160         private $mTitleValue = null;
 161
 162         /** @var bool Would deleting this page be a big deletion? */
 163         private $mIsBigDeletion = null;
 164         // @}
 165
 166         /**
 167          * B/C kludge: provide a TitleParser for use by Title.
 168          * Ideally, Title would have no methods that need this.
 169          * Avoid usage of this singleton by using TitleValue
 170          * and the associated services when possible.
 171          *
 172          * @return TitleParser
 173          */
 174         private static function getTitleParser() {
 175                 global $wgContLang, $wgLocalInterwikis;
 176
 177                 static $titleCodec = null;
 178                 static $titleCodecFingerprint = null;
 179
 180                 // $wgContLang and $wgLocalInterwikis may change (especially while testing),
 181                 // make sure we are using the right one. To detect changes over the course
 182                 // of a request, we remember a fingerprint of the config used to create the
 183                 // codec singleton, and re-create it if the fingerprint doesn't match.
 184                 $fingerprint = spl_object_hash( $wgContLang ) . '|' . join( '+', $wgLocalInterwikis );
 185
 186                 if ( $fingerprint !== $titleCodecFingerprint ) {
 187                         $titleCodec = null;
 188                 }
 189
 190                 if ( !$titleCodec ) {
 191                         $titleCodec = new MediaWikiTitleCodec(
 192                                 $wgContLang,
 193                                 GenderCache::singleton(),
 194                                 $wgLocalInterwikis
 195                         );
 196                         $titleCodecFingerprint = $fingerprint;
 197                 }
 198
 199                 return $titleCodec;
 200         }
 201
 202         /**
 203          * B/C kludge: provide a TitleParser for use by Title.
 204          * Ideally, Title would have no methods that need this.
 205          * Avoid usage of this singleton by using TitleValue
 206          * and the associated services when possible.
 207          *
 208          * @return TitleFormatter
 209          */
 210         private static function getTitleFormatter() {
 211                 //NOTE: we know that getTitleParser() returns a MediaWikiTitleCodec,
 212                 //      which implements TitleFormatter.
 213                 return self::getTitleParser();
 214         }
 215
 216         function __construct() {
 217         }
 218
 219         /**
 220          * Create a new Title from a prefixed DB key
 221          *
 222          * @param string $key The database key, which has underscores
 223          *      instead of spaces, possibly including namespace and
 224          *      interwiki prefixes
 225          * @return Title|null Title, or null on an error
 226          */
 227         public static function newFromDBkey( $key ) {
 228                 $t = new Title();
 229                 $t->mDbkeyform = $key;
 230                 if ( $t->secureAndSplit() ) {
 231                         return $t;
 232                 } else {
 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 MWException
 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 MWException( 'Title::newFromText given an object' );
 267                 }
 268
 269                 $cache = self::getTitleCache();
 270
 271                 /**
 272                  * Wiki pages often contain multiple links to the same page.
 273                  * Title normalization and parsing can become expensive on
 274                  * pages with many links, so we can save a little time by
 275                  * caching them.
 276                  *
 277                  * In theory these are value objects and won't get changed...
 278                  */
 279                 if ( $defaultNamespace == NS_MAIN && $cache->has( $text ) ) {
 280                         return $cache->get( $text );
 281                 }
 282
 283                 # Convert things like &eacute; &#257; or &#x3017; into normalized (bug 14952) text
 284                 $filteredText = Sanitizer::decodeCharReferencesAndNormalize( $text );
 285
 286                 $t = new Title();
 287                 $t->mDbkeyform = str_replace( ' ', '_', $filteredText );
 288                 $t->mDefaultNamespace = intval( $defaultNamespace );
 289
 290                 if ( $t->secureAndSplit() ) {
 291                         if ( $defaultNamespace == NS_MAIN ) {
 292                                 $cache->set( $text, $t );
 293                         }
 294                         return $t;
 295                 } else {
 296                         return null;
 297                 }
 298         }
 299
 300         /**
 301          * THIS IS NOT THE FUNCTION YOU WANT. Use Title::newFromText().
 302          *
 303          * Example of wrong and broken code:
 304          * $title = Title::newFromURL( $wgRequest->getVal( 'title' ) );
 305          *
 306          * Example of right code:
 307          * $title = Title::newFromText( $wgRequest->getVal( 'title' ) );
 308          *
 309          * Create a new Title from URL-encoded text. Ensures that
 310          * the given title's length does not exceed the maximum.
 311          *
 312          * @param string $url The title, as might be taken from a URL
 313          * @return Title|null The new object, or null on an error
 314          */
 315         public static function newFromURL( $url ) {
 316                 $t = new Title();
 317
 318                 # For compatibility with old buggy URLs. "+" is usually not valid in titles,
 319                 # but some URLs used it as a space replacement and they still come
 320                 # from some external search tools.
 321                 if ( strpos( self::legalChars(), '+' ) === false ) {
 322                         $url = str_replace( '+', ' ', $url );
 323                 }
 324
 325                 $t->mDbkeyform = str_replace( ' ', '_', $url );
 326                 if ( $t->secureAndSplit() ) {
 327                         return $t;
 328                 } else {
 329                         return null;
 330                 }
 331         }
 332
 333         /**
 334          * @return MapCacheLRU
 335          */
 336         private static function getTitleCache() {
 337                 if ( self::$titleCache == null ) {
 338                         self::$titleCache = new MapCacheLRU( self::CACHE_MAX );
 339                 }
 340                 return self::$titleCache;
 341         }
 342
 343         /**
 344          * Returns a list of fields that are to be selected for initializing Title
 345          * objects or LinkCache entries. Uses $wgContentHandlerUseDB to determine
 346          * whether to include page_content_model.
 347          *
 348          * @return array
 349          */
 350         protected static function getSelectFields() {
 351                 global $wgContentHandlerUseDB;
 352
 353                 $fields = array(
 354                         'page_namespace', 'page_title', 'page_id',
 355                         'page_len', 'page_is_redirect', 'page_latest',
 356                 );
 357
 358                 if ( $wgContentHandlerUseDB ) {
 359                         $fields[] = 'page_content_model';
 360                 }
 361
 362                 return $fields;
 363         }
 364
 365         /**
 366          * Create a new Title from an article ID
 367          *
 368          * @param int $id The page_id corresponding to the Title to create
 369          * @param int $flags Use Title::GAID_FOR_UPDATE to use master
 370          * @return Title|null The new object, or null on an error
 371          */
 372         public static function newFromID( $id, $flags = 0 ) {
 373                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
 374                 $row = $db->selectRow(
 375                         'page',
 376                         self::getSelectFields(),
 377                         array( 'page_id' => $id ),
 378                         __METHOD__
 379                 );
 380                 if ( $row !== false ) {
 381                         $title = Title::newFromRow( $row );
 382                 } else {
 383                         $title = null;
 384                 }
 385                 return $title;
 386         }
 387
 388         /**
 389          * Make an array of titles from an array of IDs
 390          *
 391          * @param int[] $ids Array of IDs
 392          * @return Title[] Array of Titles
 393          */
 394         public static function newFromIDs( $ids ) {
 395                 if ( !count( $ids ) ) {
 396                         return array();
 397                 }
 398                 $dbr = wfGetDB( DB_SLAVE );
 399
 400                 $res = $dbr->select(
 401                         'page',
 402                         self::getSelectFields(),
 403                         array( 'page_id' => $ids ),
 404                         __METHOD__
 405                 );
 406
 407                 $titles = array();
 408                 foreach ( $res as $row ) {
 409                         $titles[] = Title::newFromRow( $row );
 410                 }
 411                 return $titles;
 412         }
 413
 414         /**
 415          * Make a Title object from a DB row
 416          *
 417          * @param stdClass $row Object database row (needs at least page_title,page_namespace)
 418          * @return Title Corresponding Title
 419          */
 420         public static function newFromRow( $row ) {
 421                 $t = self::makeTitle( $row->page_namespace, $row->page_title );
 422                 $t->loadFromRow( $row );
 423                 return $t;
 424         }
 425
 426         /**
 427          * Load Title object fields from a DB row.
 428          * If false is given, the title will be treated as non-existing.
 429          *
 430          * @param stdClass|bool $row Database row
 431          */
 432         public function loadFromRow( $row ) {
 433                 if ( $row ) { // page found
 434                         if ( isset( $row->page_id ) ) {
 435                                 $this->mArticleID = (int)$row->page_id;
 436                         }
 437                         if ( isset( $row->page_len ) ) {
 438                                 $this->mLength = (int)$row->page_len;
 439                         }
 440                         if ( isset( $row->page_is_redirect ) ) {
 441                                 $this->mRedirect = (bool)$row->page_is_redirect;
 442                         }
 443                         if ( isset( $row->page_latest ) ) {
 444                                 $this->mLatestID = (int)$row->page_latest;
 445                         }
 446                         if ( isset( $row->page_content_model ) ) {
 447                                 $this->mContentModel = strval( $row->page_content_model );
 448                         } else {
 449                                 $this->mContentModel = false; # initialized lazily in getContentModel()
 450                         }
 451                         if ( isset( $row->page_lang ) ) {
 452                                 $this->mDbPageLanguage = (string)$row->page_lang;
 453                         }
 454                 } else { // page not found
 455                         $this->mArticleID = 0;
 456                         $this->mLength = 0;
 457                         $this->mRedirect = false;
 458                         $this->mLatestID = 0;
 459                         $this->mContentModel = false; # initialized lazily in getContentModel()
 460                 }
 461         }
 462
 463         /**
 464          * Create a new Title from a namespace index and a DB key.
 465          * It's assumed that $ns and $title are *valid*, for instance when
 466          * they came directly from the database or a special page name.
 467          * For convenience, spaces are converted to underscores so that
 468          * eg user_text fields can be used directly.
 469          *
 470          * @param int $ns The namespace of the article
 471          * @param string $title The unprefixed database key form
 472          * @param string $fragment The link fragment (after the "#")
 473          * @param string $interwiki The interwiki prefix
 474          * @return Title The new object
 475          */
 476         public static function &makeTitle( $ns, $title, $fragment = '', $interwiki = '' ) {
 477                 $t = new Title();
 478                 $t->mInterwiki = $interwiki;
 479                 $t->mFragment = $fragment;
 480                 $t->mNamespace = $ns = intval( $ns );
 481                 $t->mDbkeyform = str_replace( ' ', '_', $title );
 482                 $t->mArticleID = ( $ns >= 0 ) ? -1 : 0;
 483                 $t->mUrlform = wfUrlencode( $t->mDbkeyform );
 484                 $t->mTextform = str_replace( '_', ' ', $title );
 485                 $t->mContentModel = false; # initialized lazily in getContentModel()
 486                 return $t;
 487         }
 488
 489         /**
 490          * Create a new Title from a namespace index and a DB key.
 491          * The parameters will be checked for validity, which is a bit slower
 492          * than makeTitle() but safer for user-provided data.
 493          *
 494          * @param int $ns The namespace of the article
 495          * @param string $title Database key form
 496          * @param string $fragment The link fragment (after the "#")
 497          * @param string $interwiki Interwiki prefix
 498          * @return Title The new object, or null on an error
 499          */
 500         public static function makeTitleSafe( $ns, $title, $fragment = '', $interwiki = '' ) {
 501                 if ( !MWNamespace::exists( $ns ) ) {
 502                         return null;
 503                 }
 504
 505                 $t = new Title();
 506                 $t->mDbkeyform = Title::makeName( $ns, $title, $fragment, $interwiki, true );
 507                 if ( $t->secureAndSplit() ) {
 508                         return $t;
 509                 } else {
 510                         return null;
 511                 }
 512         }
 513
 514         /**
 515          * Create a new Title for the Main Page
 516          *
 517          * @return Title The new object
 518          */
 519         public static function newMainPage() {
 520                 $title = Title::newFromText( wfMessage( 'mainpage' )->inContentLanguage()->text() );
 521                 // Don't give fatal errors if the message is broken
 522                 if ( !$title ) {
 523                         $title = Title::newFromText( 'Main Page' );
 524                 }
 525                 return $title;
 526         }
 527
 528         /**
 529          * Extract a redirect destination from a string and return the
 530          * Title, or null if the text doesn't contain a valid redirect
 531          * This will only return the very next target, useful for
 532          * the redirect table and other checks that don't need full recursion
 533          *
 534          * @param string $text Text with possible redirect
 535          * @return Title The corresponding Title
 536          * @deprecated since 1.21, use Content::getRedirectTarget instead.
 537          */
 538         public static function newFromRedirect( $text ) {
 539                 ContentHandler::deprecated( __METHOD__, '1.21' );
 540
 541                 $content = ContentHandler::makeContent( $text, null, CONTENT_MODEL_WIKITEXT );
 542                 return $content->getRedirectTarget();
 543         }
 544
 545         /**
 546          * Extract a redirect destination from a string and return the
 547          * Title, or null if the text doesn't contain a valid redirect
 548          * This will recurse down $wgMaxRedirects times or until a non-redirect target is hit
 549          * in order to provide (hopefully) the Title of the final destination instead of another redirect
 550          *
 551          * @param string $text Text with possible redirect
 552          * @return Title
 553          * @deprecated since 1.21, use Content::getUltimateRedirectTarget instead.
 554          */
 555         public static function newFromRedirectRecurse( $text ) {
 556                 ContentHandler::deprecated( __METHOD__, '1.21' );
 557
 558                 $content = ContentHandler::makeContent( $text, null, CONTENT_MODEL_WIKITEXT );
 559                 return $content->getUltimateRedirectTarget();
 560         }
 561
 562         /**
 563          * Extract a redirect destination from a string and return an
 564          * array of Titles, or null if the text doesn't contain a valid redirect
 565          * The last element in the array is the final destination after all redirects
 566          * have been resolved (up to $wgMaxRedirects times)
 567          *
 568          * @param string $text Text with possible redirect
 569          * @return Title[] Array of Titles, with the destination last
 570          * @deprecated since 1.21, use Content::getRedirectChain instead.
 571          */
 572         public static function newFromRedirectArray( $text ) {
 573                 ContentHandler::deprecated( __METHOD__, '1.21' );
 574
 575                 $content = ContentHandler::makeContent( $text, null, CONTENT_MODEL_WIKITEXT );
 576                 return $content->getRedirectChain();
 577         }
 578
 579         /**
 580          * Get the prefixed DB key associated with an ID
 581          *
 582          * @param int $id The page_id of the article
 583          * @return Title|null An object representing the article, or null if no such article was found
 584          */
 585         public static function nameOf( $id ) {
 586                 $dbr = wfGetDB( DB_SLAVE );
 587
 588                 $s = $dbr->selectRow(
 589                         'page',
 590                         array( 'page_namespace', 'page_title' ),
 591                         array( 'page_id' => $id ),
 592                         __METHOD__
 593                 );
 594                 if ( $s === false ) {
 595                         return null;
 596                 }
 597
 598                 $n = self::makeName( $s->page_namespace, $s->page_title );
 599                 return $n;
 600         }
 601
 602         /**
 603          * Get a regex character class describing the legal characters in a link
 604          *
 605          * @return string The list of characters, not delimited
 606          */
 607         public static function legalChars() {
 608                 global $wgLegalTitleChars;
 609                 return $wgLegalTitleChars;
 610         }
 611
 612         /**
 613          * Returns a simple regex that will match on characters and sequences invalid in titles.
 614          * Note that this doesn't pick up many things that could be wrong with titles, but that
 615          * replacing this regex with something valid will make many titles valid.
 616          *
 617          * @deprecated since 1.25, use MediaWikiTitleCodec::getTitleInvalidRegex() instead
 618          *
 619          * @return string Regex string
 620          */
 621         static function getTitleInvalidRegex() {
 622                 wfDeprecated( __METHOD__, '1.25' );
 623                 return MediaWikiTitleCodec::getTitleInvalidRegex();
 624         }
 625
 626         /**
 627          * Utility method for converting a character sequence from bytes to Unicode.
 628          *
 629          * Primary usecase being converting $wgLegalTitleChars to a sequence usable in
 630          * javascript, as PHP uses UTF-8 bytes where javascript uses Unicode code units.
 631          *
 632          * @param string $byteClass
 633          * @return string
 634          */
 635         public static function convertByteClassToUnicodeClass( $byteClass ) {
 636                 $length = strlen( $byteClass );
 637                 // Input token queue
 638                 $x0 = $x1 = $x2 = '';
 639                 // Decoded queue
 640                 $d0 = $d1 = $d2 = '';
 641                 // Decoded integer codepoints
 642                 $ord0 = $ord1 = $ord2 = 0;
 643                 // Re-encoded queue
 644                 $r0 = $r1 = $r2 = '';
 645                 // Output
 646                 $out = '';
 647                 // Flags
 648                 $allowUnicode = false;
 649                 for ( $pos = 0; $pos < $length; $pos++ ) {
 650                         // Shift the queues down
 651                         $x2 = $x1;
 652                         $x1 = $x0;
 653                         $d2 = $d1;
 654                         $d1 = $d0;
 655                         $ord2 = $ord1;
 656                         $ord1 = $ord0;
 657                         $r2 = $r1;
 658                         $r1 = $r0;
 659                         // Load the current input token and decoded values
 660                         $inChar = $byteClass[$pos];
 661                         if ( $inChar == '\\' ) {
 662                                 if ( preg_match( '/x([0-9a-fA-F]{2})/A', $byteClass, $m, 0, $pos + 1 ) ) {
 663                                         $x0 = $inChar . $m[0];
 664                                         $d0 = chr( hexdec( $m[1] ) );
 665                                         $pos += strlen( $m[0] );
 666                                 } elseif ( preg_match( '/[0-7]{3}/A', $byteClass, $m, 0, $pos + 1 ) ) {
 667                                         $x0 = $inChar . $m[0];
 668                                         $d0 = chr( octdec( $m[0] ) );
 669                                         $pos += strlen( $m[0] );
 670                                 } elseif ( $pos + 1 >= $length ) {
 671                                         $x0 = $d0 = '\\';
 672                                 } else {
 673                                         $d0 = $byteClass[$pos + 1];
 674                                         $x0 = $inChar . $d0;
 675                                         $pos += 1;
 676                                 }
 677                         } else {
 678                                 $x0 = $d0 = $inChar;
 679                         }
 680                         $ord0 = ord( $d0 );
 681                         // Load the current re-encoded value
 682                         if ( $ord0 < 32 || $ord0 == 0x7f ) {
 683                                 $r0 = sprintf( '\x%02x', $ord0 );
 684                         } elseif ( $ord0 >= 0x80 ) {
 685                                 // Allow unicode if a single high-bit character appears
 686                                 $r0 = sprintf( '\x%02x', $ord0 );
 687                                 $allowUnicode = true;
 688                         } elseif ( strpos( '-\\[]^', $d0 ) !== false ) {
 689                                 $r0 = '\\' . $d0;
 690                         } else {
 691                                 $r0 = $d0;
 692                         }
 693                         // Do the output
 694                         if ( $x0 !== '' && $x1 === '-' && $x2 !== '' ) {
 695                                 // Range
 696                                 if ( $ord2 > $ord0 ) {
 697                                         // Empty range
 698                                 } elseif ( $ord0 >= 0x80 ) {
 699                                         // Unicode range
 700                                         $allowUnicode = true;
 701                                         if ( $ord2 < 0x80 ) {
 702                                                 // Keep the non-unicode section of the range
 703                                                 $out .= "$r2-\\x7F";
 704                                         }
 705                                 } else {
 706                                         // Normal range
 707                                         $out .= "$r2-$r0";
 708                                 }
 709                                 // Reset state to the initial value
 710                                 $x0 = $x1 = $d0 = $d1 = $r0 = $r1 = '';
 711                         } elseif ( $ord2 < 0x80 ) {
 712                                 // ASCII character
 713                                 $out .= $r2;
 714                         }
 715                 }
 716                 if ( $ord1 < 0x80 ) {
 717                         $out .= $r1;
 718                 }
 719                 if ( $ord0 < 0x80 ) {
 720                         $out .= $r0;
 721                 }
 722                 if ( $allowUnicode ) {
 723                         $out .= '\u0080-\uFFFF';
 724                 }
 725                 return $out;
 726         }
 727
 728         /**
 729          * Make a prefixed DB key from a DB key and a namespace index
 730          *
 731          * @param int $ns Numerical representation of the namespace
 732          * @param string $title The DB key form the title
 733          * @param string $fragment The link fragment (after the "#")
 734          * @param string $interwiki The interwiki prefix
 735          * @param bool $canoncialNamespace If true, use the canonical name for
 736          *   $ns instead of the localized version.
 737          * @return string The prefixed form of the title
 738          */
 739         public static function makeName( $ns, $title, $fragment = '', $interwiki = '',
 740                 $canoncialNamespace = false
 741         ) {
 742                 global $wgContLang;
 743
 744                 if ( $canoncialNamespace ) {
 745                         $namespace = MWNamespace::getCanonicalName( $ns );
 746                 } else {
 747                         $namespace = $wgContLang->getNsText( $ns );
 748                 }
 749                 $name = $namespace == '' ? $title : "$namespace:$title";
 750                 if ( strval( $interwiki ) != '' ) {
 751                         $name = "$interwiki:$name";
 752                 }
 753                 if ( strval( $fragment ) != '' ) {
 754                         $name .= '#' . $fragment;
 755                 }
 756                 return $name;
 757         }
 758
 759         /**
 760          * Escape a text fragment, say from a link, for a URL
 761          *
 762          * @param string $fragment Containing a URL or link fragment (after the "#")
 763          * @return string Escaped string
 764          */
 765         static function escapeFragmentForURL( $fragment ) {
 766                 # Note that we don't urlencode the fragment.  urlencoded Unicode
 767                 # fragments appear not to work in IE (at least up to 7) or in at least
 768                 # one version of Opera 9.x.  The W3C validator, for one, doesn't seem
 769                 # to care if they aren't encoded.
 770                 return Sanitizer::escapeId( $fragment, 'noninitial' );
 771         }
 772
 773         /**
 774          * Callback for usort() to do title sorts by (namespace, title)
 775          *
 776          * @param Title $a
 777          * @param Title $b
 778          *
 779          * @return int Result of string comparison, or namespace comparison
 780          */
 781         public static function compare( $a, $b ) {
 782                 if ( $a->getNamespace() == $b->getNamespace() ) {
 783                         return strcmp( $a->getText(), $b->getText() );
 784                 } else {
 785                         return $a->getNamespace() - $b->getNamespace();
 786                 }
 787         }
 788
 789         /**
 790          * Determine whether the object refers to a page within
 791          * this project (either this wiki or a wiki with a local
 792          * interwiki, see https://www.mediawiki.org/wiki/Manual:Interwiki_table#iw_local )
 793          *
 794          * @return bool True if this is an in-project interwiki link or a wikilink, false otherwise
 795          */
 796         public function isLocal() {
 797                 if ( $this->isExternal() ) {
 798                         $iw = Interwiki::fetch( $this->mInterwiki );
 799                         if ( $iw ) {
 800                                 return $iw->isLocal();
 801                         }
 802                 }
 803                 return true;
 804         }
 805
 806         /**
 807          * Is this Title interwiki?
 808          *
 809          * @return bool
 810          */
 811         public function isExternal() {
 812                 return $this->mInterwiki !== '';
 813         }
 814
 815         /**
 816          * Get the interwiki prefix
 817          *
 818          * Use Title::isExternal to check if a interwiki is set
 819          *
 820          * @return string Interwiki prefix
 821          */
 822         public function getInterwiki() {
 823                 return $this->mInterwiki;
 824         }
 825
 826         /**
 827          * Was this a local interwiki link?
 828          *
 829          * @return bool
 830          */
 831         public function wasLocalInterwiki() {
 832                 return $this->mLocalInterwiki;
 833         }
 834
 835         /**
 836          * Determine whether the object refers to a page within
 837          * this project and is transcludable.
 838          *
 839          * @return bool True if this is transcludable
 840          */
 841         public function isTrans() {
 842                 if ( !$this->isExternal() ) {
 843                         return false;
 844                 }
 845
 846                 return Interwiki::fetch( $this->mInterwiki )->isTranscludable();
 847         }
 848
 849         /**
 850          * Returns the DB name of the distant wiki which owns the object.
 851          *
 852          * @return string The DB name
 853          */
 854         public function getTransWikiID() {
 855                 if ( !$this->isExternal() ) {
 856                         return false;
 857                 }
 858
 859                 return Interwiki::fetch( $this->mInterwiki )->getWikiID();
 860         }
 861
 862         /**
 863          * Get a TitleValue object representing this Title.
 864          *
 865          * @note Not all valid Titles have a corresponding valid TitleValue
 866          * (e.g. TitleValues cannot represent page-local links that have a
 867          * fragment but no title text).
 868          *
 869          * @return TitleValue|null
 870          */
 871         public function getTitleValue() {
 872                 if ( $this->mTitleValue === null ) {
 873                         try {
 874                                 $this->mTitleValue = new TitleValue(
 875                                         $this->getNamespace(),
 876                                         $this->getDBkey(),
 877                                         $this->getFragment() );
 878                         } catch ( InvalidArgumentException $ex ) {
 879                                 wfDebug( __METHOD__ . ': Can\'t create a TitleValue for [[' .
 880                                         $this->getPrefixedText() . ']]: ' . $ex->getMessage() . "\n" );
 881                         }
 882                 }
 883
 884                 return $this->mTitleValue;
 885         }
 886
 887         /**
 888          * Get the text form (spaces not underscores) of the main part
 889          *
 890          * @return string Main part of the title
 891          */
 892         public function getText() {
 893                 return $this->mTextform;
 894         }
 895
 896         /**
 897          * Get the URL-encoded form of the main part
 898          *
 899          * @return string Main part of the title, URL-encoded
 900          */
 901         public function getPartialURL() {
 902                 return $this->mUrlform;
 903         }
 904
 905         /**
 906          * Get the main part with underscores
 907          *
 908          * @return string Main part of the title, with underscores
 909          */
 910         public function getDBkey() {
 911                 return $this->mDbkeyform;
 912         }
 913
 914         /**
 915          * Get the DB key with the initial letter case as specified by the user
 916          *
 917          * @return string DB key
 918          */
 919         function getUserCaseDBKey() {
 920                 if ( !is_null( $this->mUserCaseDBKey ) ) {
 921                         return $this->mUserCaseDBKey;
 922                 } else {
 923                         // If created via makeTitle(), $this->mUserCaseDBKey is not set.
 924                         return $this->mDbkeyform;
 925                 }
 926         }
 927
 928         /**
 929          * Get the namespace index, i.e. one of the NS_xxxx constants.
 930          *
 931          * @return int Namespace index
 932          */
 933         public function getNamespace() {
 934                 return $this->mNamespace;
 935         }
 936
 937         /**
 938          * Get the page's content model id, see the CONTENT_MODEL_XXX constants.
 939          *
 940          * @throws MWException
 941          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
 942          * @return string Content model id
 943          */
 944         public function getContentModel( $flags = 0 ) {
 945                 # Calling getArticleID() loads the field from cache as needed
 946                 if ( !$this->mContentModel && $this->getArticleID( $flags ) ) {
 947                         $linkCache = LinkCache::singleton();
 948                         $this->mContentModel = $linkCache->getGoodLinkFieldObj( $this, 'model' );
 949                 }
 950
 951                 if ( !$this->mContentModel ) {
 952                         $this->mContentModel = ContentHandler::getDefaultModelFor( $this );
 953                 }
 954
 955                 if ( !$this->mContentModel ) {
 956                         throw new MWException( 'Failed to determine content model!' );
 957                 }
 958
 959                 return $this->mContentModel;
 960         }
 961
 962         /**
 963          * Convenience method for checking a title's content model name
 964          *
 965          * @param string $id The content model ID (use the CONTENT_MODEL_XXX constants).
 966          * @return bool True if $this->getContentModel() == $id
 967          */
 968         public function hasContentModel( $id ) {
 969                 return $this->getContentModel() == $id;
 970         }
 971
 972         /**
 973          * Get the namespace text
 974          *
 975          * @return string Namespace text
 976          */
 977         public function getNsText() {
 978                 if ( $this->isExternal() ) {
 979                         // This probably shouldn't even happen. ohh man, oh yuck.
 980                         // But for interwiki transclusion it sometimes does.
 981                         // Shit. Shit shit shit.
 982                         //
 983                         // Use the canonical namespaces if possible to try to
 984                         // resolve a foreign namespace.
 985                         if ( MWNamespace::exists( $this->mNamespace ) ) {
 986                                 return MWNamespace::getCanonicalName( $this->mNamespace );
 987                         }
 988                 }
 989
 990                 try {
 991                         $formatter = self::getTitleFormatter();
 992                         return $formatter->getNamespaceName( $this->mNamespace, $this->mDbkeyform );
 993                 } catch ( InvalidArgumentException $ex ) {
 994                         wfDebug( __METHOD__ . ': ' . $ex->getMessage() . "\n" );
 995                         return false;
 996                 }
 997         }
 998
 999         /**
1000          * Get the namespace text of the subject (rather than talk) page
1001          *
1002          * @return string Namespace text
1003          */
1004         public function getSubjectNsText() {
1005                 global $wgContLang;
1006                 return $wgContLang->getNsText( MWNamespace::getSubject( $this->mNamespace ) );
1007         }
1008
1009         /**
1010          * Get the namespace text of the talk page
1011          *
1012          * @return string Namespace text
1013          */
1014         public function getTalkNsText() {
1015                 global $wgContLang;
1016                 return $wgContLang->getNsText( MWNamespace::getTalk( $this->mNamespace ) );
1017         }
1018
1019         /**
1020          * Could this title have a corresponding talk page?
1021          *
1022          * @return bool
1023          */
1024         public function canTalk() {
1025                 return MWNamespace::canTalk( $this->mNamespace );
1026         }
1027
1028         /**
1029          * Is this in a namespace that allows actual pages?
1030          *
1031          * @return bool
1032          */
1033         public function canExist() {
1034                 return $this->mNamespace >= NS_MAIN;
1035         }
1036
1037         /**
1038          * Can this title be added to a user's watchlist?
1039          *
1040          * @return bool
1041          */
1042         public function isWatchable() {
1043                 return !$this->isExternal() && MWNamespace::isWatchable( $this->getNamespace() );
1044         }
1045
1046         /**
1047          * Returns true if this is a special page.
1048          *
1049          * @return bool
1050          */
1051         public function isSpecialPage() {
1052                 return $this->getNamespace() == NS_SPECIAL;
1053         }
1054
1055         /**
1056          * Returns true if this title resolves to the named special page
1057          *
1058          * @param string $name The special page name
1059          * @return bool
1060          */
1061         public function isSpecial( $name ) {
1062                 if ( $this->isSpecialPage() ) {
1063                         list( $thisName, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $this->getDBkey() );
1064                         if ( $name == $thisName ) {
1065                                 return true;
1066                         }
1067                 }
1068                 return false;
1069         }
1070
1071         /**
1072          * If the Title refers to a special page alias which is not the local default, resolve
1073          * the alias, and localise the name as necessary.  Otherwise, return $this
1074          *
1075          * @return Title
1076          */
1077         public function fixSpecialName() {
1078                 if ( $this->isSpecialPage() ) {
1079                         list( $canonicalName, $par ) = SpecialPageFactory::resolveAlias( $this->mDbkeyform );
1080                         if ( $canonicalName ) {
1081                                 $localName = SpecialPageFactory::getLocalNameFor( $canonicalName, $par );
1082                                 if ( $localName != $this->mDbkeyform ) {
1083                                         return Title::makeTitle( NS_SPECIAL, $localName );
1084                                 }
1085                         }
1086                 }
1087                 return $this;
1088         }
1089
1090         /**
1091          * Returns true if the title is inside the specified namespace.
1092          *
1093          * Please make use of this instead of comparing to getNamespace()
1094          * This function is much more resistant to changes we may make
1095          * to namespaces than code that makes direct comparisons.
1096          * @param int $ns The namespace
1097          * @return bool
1098          * @since 1.19
1099          */
1100         public function inNamespace( $ns ) {
1101                 return MWNamespace::equals( $this->getNamespace(), $ns );
1102         }
1103
1104         /**
1105          * Returns true if the title is inside one of the specified namespaces.
1106          *
1107          * @param int $namespaces,... The namespaces to check for
1108          * @return bool
1109          * @since 1.19
1110          */
1111         public function inNamespaces( /* ... */ ) {
1112                 $namespaces = func_get_args();
1113                 if ( count( $namespaces ) > 0 && is_array( $namespaces[0] ) ) {
1114                         $namespaces = $namespaces[0];
1115                 }
1116
1117                 foreach ( $namespaces as $ns ) {
1118                         if ( $this->inNamespace( $ns ) ) {
1119                                 return true;
1120                         }
1121                 }
1122
1123                 return false;
1124         }
1125
1126         /**
1127          * Returns true if the title has the same subject namespace as the
1128          * namespace specified.
1129          * For example this method will take NS_USER and return true if namespace
1130          * is either NS_USER or NS_USER_TALK since both of them have NS_USER
1131          * as their subject namespace.
1132          *
1133          * This is MUCH simpler than individually testing for equivalence
1134          * against both NS_USER and NS_USER_TALK, and is also forward compatible.
1135          * @since 1.19
1136          * @param int $ns
1137          * @return bool
1138          */
1139         public function hasSubjectNamespace( $ns ) {
1140                 return MWNamespace::subjectEquals( $this->getNamespace(), $ns );
1141         }
1142
1143         /**
1144          * Is this Title in a namespace which contains content?
1145          * In other words, is this a content page, for the purposes of calculating
1146          * statistics, etc?
1147          *
1148          * @return bool
1149          */
1150         public function isContentPage() {
1151                 return MWNamespace::isContent( $this->getNamespace() );
1152         }
1153
1154         /**
1155          * Would anybody with sufficient privileges be able to move this page?
1156          * Some pages just aren't movable.
1157          *
1158          * @return bool
1159          */
1160         public function isMovable() {
1161                 if ( !MWNamespace::isMovable( $this->getNamespace() ) || $this->isExternal() ) {
1162                         // Interwiki title or immovable namespace. Hooks don't get to override here
1163                         return false;
1164                 }
1165
1166                 $result = true;
1167                 Hooks::run( 'TitleIsMovable', array( $this, &$result ) );
1168                 return $result;
1169         }
1170
1171         /**
1172          * Is this the mainpage?
1173          * @note Title::newFromText seems to be sufficiently optimized by the title
1174          * cache that we don't need to over-optimize by doing direct comparisons and
1175          * accidentally creating new bugs where $title->equals( Title::newFromText() )
1176          * ends up reporting something differently than $title->isMainPage();
1177          *
1178          * @since 1.18
1179          * @return bool
1180          */
1181         public function isMainPage() {
1182                 return $this->equals( Title::newMainPage() );
1183         }
1184
1185         /**
1186          * Is this a subpage?
1187          *
1188          * @return bool
1189          */
1190         public function isSubpage() {
1191                 return MWNamespace::hasSubpages( $this->mNamespace )
1192                         ? strpos( $this->getText(), '/' ) !== false
1193                         : false;
1194         }
1195
1196         /**
1197          * Is this a conversion table for the LanguageConverter?
1198          *
1199          * @return bool
1200          */
1201         public function isConversionTable() {
1202                 // @todo ConversionTable should become a separate content model.
1203
1204                 return $this->getNamespace() == NS_MEDIAWIKI &&
1205                         strpos( $this->getText(), 'Conversiontable/' ) === 0;
1206         }
1207
1208         /**
1209          * Does that page contain wikitext, or it is JS, CSS or whatever?
1210          *
1211          * @return bool
1212          */
1213         public function isWikitextPage() {
1214                 return $this->hasContentModel( CONTENT_MODEL_WIKITEXT );
1215         }
1216
1217         /**
1218          * Could this page contain custom CSS or JavaScript for the global UI.
1219          * This is generally true for pages in the MediaWiki namespace having CONTENT_MODEL_CSS
1220          * or CONTENT_MODEL_JAVASCRIPT.
1221          *
1222          * This method does *not* return true for per-user JS/CSS. Use isCssJsSubpage()
1223          * for that!
1224          *
1225          * Note that this method should not return true for pages that contain and
1226          * show "inactive" CSS or JS.
1227          *
1228          * @return bool
1229          */
1230         public function isCssOrJsPage() {
1231                 $isCssOrJsPage = NS_MEDIAWIKI == $this->mNamespace
1232                         && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1233                                 || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1234
1235                 # @note This hook is also called in ContentHandler::getDefaultModel.
1236                 #   It's called here again to make sure hook functions can force this
1237                 #   method to return true even outside the MediaWiki namespace.
1238
1239                 Hooks::run( 'TitleIsCssOrJsPage', array( $this, &$isCssOrJsPage ), '1.25' );
1240
1241                 return $isCssOrJsPage;
1242         }
1243
1244         /**
1245          * Is this a .css or .js subpage of a user page?
1246          * @return bool
1247          */
1248         public function isCssJsSubpage() {
1249                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1250                                 && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1251                                         || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) ) );
1252         }
1253
1254         /**
1255          * Trim down a .css or .js subpage title to get the corresponding skin name
1256          *
1257          * @return string Containing skin name from .css or .js subpage title
1258          */
1259         public function getSkinFromCssJsSubpage() {
1260                 $subpage = explode( '/', $this->mTextform );
1261                 $subpage = $subpage[count( $subpage ) - 1];
1262                 $lastdot = strrpos( $subpage, '.' );
1263                 if ( $lastdot === false ) {
1264                         return $subpage; # Never happens: only called for names ending in '.css' or '.js'
1265                 }
1266                 return substr( $subpage, 0, $lastdot );
1267         }
1268
1269         /**
1270          * Is this a .css subpage of a user page?
1271          *
1272          * @return bool
1273          */
1274         public function isCssSubpage() {
1275                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1276                         && $this->hasContentModel( CONTENT_MODEL_CSS ) );
1277         }
1278
1279         /**
1280          * Is this a .js subpage of a user page?
1281          *
1282          * @return bool
1283          */
1284         public function isJsSubpage() {
1285                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1286                         && $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1287         }
1288
1289         /**
1290          * Is this a talk page of some sort?
1291          *
1292          * @return bool
1293          */
1294         public function isTalkPage() {
1295                 return MWNamespace::isTalk( $this->getNamespace() );
1296         }
1297
1298         /**
1299          * Get a Title object associated with the talk page of this article
1300          *
1301          * @return Title The object for the talk page
1302          */
1303         public function getTalkPage() {
1304                 return Title::makeTitle( MWNamespace::getTalk( $this->getNamespace() ), $this->getDBkey() );
1305         }
1306
1307         /**
1308          * Get a title object associated with the subject page of this
1309          * talk page
1310          *
1311          * @return Title The object for the subject page
1312          */
1313         public function getSubjectPage() {
1314                 // Is this the same title?
1315                 $subjectNS = MWNamespace::getSubject( $this->getNamespace() );
1316                 if ( $this->getNamespace() == $subjectNS ) {
1317                         return $this;
1318                 }
1319                 return Title::makeTitle( $subjectNS, $this->getDBkey() );
1320         }
1321
1322         /**
1323          * Get the other title for this page, if this is a subject page
1324          * get the talk page, if it is a subject page get the talk page
1325          *
1326          * @since 1.25
1327          * @throws MWException
1328          * @return Title
1329          */
1330         public function getOtherPage() {
1331                 if ( $this->isSpecialPage() ) {
1332                         throw new MWException( 'Special pages cannot have other pages' );
1333                 }
1334                 if ( $this->isTalkPage() ) {
1335                         return $this->getSubjectPage();
1336                 } else {
1337                         return $this->getTalkPage();
1338                 }
1339         }
1340
1341         /**
1342          * Get the default namespace index, for when there is no namespace
1343          *
1344          * @return int Default namespace index
1345          */
1346         public function getDefaultNamespace() {
1347                 return $this->mDefaultNamespace;
1348         }
1349
1350         /**
1351          * Get the Title fragment (i.e.\ the bit after the #) in text form
1352          *
1353          * Use Title::hasFragment to check for a fragment
1354          *
1355          * @return string Title fragment
1356          */
1357         public function getFragment() {
1358                 return $this->mFragment;
1359         }
1360
1361         /**
1362          * Check if a Title fragment is set
1363          *
1364          * @return bool
1365          * @since 1.23
1366          */
1367         public function hasFragment() {
1368                 return $this->mFragment !== '';
1369         }
1370
1371         /**
1372          * Get the fragment in URL form, including the "#" character if there is one
1373          * @return string Fragment in URL form
1374          */
1375         public function getFragmentForURL() {
1376                 if ( !$this->hasFragment() ) {
1377                         return '';
1378                 } else {
1379                         return '#' . Title::escapeFragmentForURL( $this->getFragment() );
1380                 }
1381         }
1382
1383         /**
1384          * Set the fragment for this title. Removes the first character from the
1385          * specified fragment before setting, so it assumes you're passing it with
1386          * an initial "#".
1387          *
1388          * Deprecated for public use, use Title::makeTitle() with fragment parameter.
1389          * Still in active use privately.
1390          *
1391          * @param string $fragment Text
1392          */
1393         public function setFragment( $fragment ) {
1394                 $this->mFragment = str_replace( '_', ' ', substr( $fragment, 1 ) );
1395         }
1396
1397         /**
1398          * Prefix some arbitrary text with the namespace or interwiki prefix
1399          * of this object
1400          *
1401          * @param string $name The text
1402          * @return string The prefixed text
1403          */
1404         private function prefix( $name ) {
1405                 $p = '';
1406                 if ( $this->isExternal() ) {
1407                         $p = $this->mInterwiki . ':';
1408                 }
1409
1410                 if ( 0 != $this->mNamespace ) {
1411                         $p .= $this->getNsText() . ':';
1412                 }
1413                 return $p . $name;
1414         }
1415
1416         /**
1417          * Get the prefixed database key form
1418          *
1419          * @return string The prefixed title, with underscores and
1420          *  any interwiki and namespace prefixes
1421          */
1422         public function getPrefixedDBkey() {
1423                 $s = $this->prefix( $this->mDbkeyform );
1424                 $s = str_replace( ' ', '_', $s );
1425                 return $s;
1426         }
1427
1428         /**
1429          * Get the prefixed title with spaces.
1430          * This is the form usually used for display
1431          *
1432          * @return string The prefixed title, with spaces
1433          */
1434         public function getPrefixedText() {
1435                 if ( $this->mPrefixedText === null ) {
1436                         $s = $this->prefix( $this->mTextform );
1437                         $s = str_replace( '_', ' ', $s );
1438                         $this->mPrefixedText = $s;
1439                 }
1440                 return $this->mPrefixedText;
1441         }
1442
1443         /**
1444          * Return a string representation of this title
1445          *
1446          * @return string Representation of this title
1447          */
1448         public function __toString() {
1449                 return $this->getPrefixedText();
1450         }
1451
1452         /**
1453          * Get the prefixed title with spaces, plus any fragment
1454          * (part beginning with '#')
1455          *
1456          * @return string The prefixed title, with spaces and the fragment, including '#'
1457          */
1458         public function getFullText() {
1459                 $text = $this->getPrefixedText();
1460                 if ( $this->hasFragment() ) {
1461                         $text .= '#' . $this->getFragment();
1462                 }
1463                 return $text;
1464         }
1465
1466         /**
1467          * Get the root page name text without a namespace, i.e. the leftmost part before any slashes
1468          *
1469          * @par Example:
1470          * @code
1471          * Title::newFromText('User:Foo/Bar/Baz')->getRootText();
1472          * # returns: 'Foo'
1473          * @endcode
1474          *
1475          * @return string Root name
1476          * @since 1.20
1477          */
1478         public function getRootText() {
1479                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1480                         return $this->getText();
1481                 }
1482
1483                 return strtok( $this->getText(), '/' );
1484         }
1485
1486         /**
1487          * Get the root page name title, i.e. the leftmost part before any slashes
1488          *
1489          * @par Example:
1490          * @code
1491          * Title::newFromText('User:Foo/Bar/Baz')->getRootTitle();
1492          * # returns: Title{User:Foo}
1493          * @endcode
1494          *
1495          * @return Title Root title
1496          * @since 1.20
1497          */
1498         public function getRootTitle() {
1499                 return Title::makeTitle( $this->getNamespace(), $this->getRootText() );
1500         }
1501
1502         /**
1503          * Get the base page name without a namespace, i.e. the part before the subpage name
1504          *
1505          * @par Example:
1506          * @code
1507          * Title::newFromText('User:Foo/Bar/Baz')->getBaseText();
1508          * # returns: 'Foo/Bar'
1509          * @endcode
1510          *
1511          * @return string Base name
1512          */
1513         public function getBaseText() {
1514                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1515                         return $this->getText();
1516                 }
1517
1518                 $parts = explode( '/', $this->getText() );
1519                 # Don't discard the real title if there's no subpage involved
1520                 if ( count( $parts ) > 1 ) {
1521                         unset( $parts[count( $parts ) - 1] );
1522                 }
1523                 return implode( '/', $parts );
1524         }
1525
1526         /**
1527          * Get the base page name title, i.e. the part before the subpage name
1528          *
1529          * @par Example:
1530          * @code
1531          * Title::newFromText('User:Foo/Bar/Baz')->getBaseTitle();
1532          * # returns: Title{User:Foo/Bar}
1533          * @endcode
1534          *
1535          * @return Title Base title
1536          * @since 1.20
1537          */
1538         public function getBaseTitle() {
1539                 return Title::makeTitle( $this->getNamespace(), $this->getBaseText() );
1540         }
1541
1542         /**
1543          * Get the lowest-level subpage name, i.e. the rightmost part after any slashes
1544          *
1545          * @par Example:
1546          * @code
1547          * Title::newFromText('User:Foo/Bar/Baz')->getSubpageText();
1548          * # returns: "Baz"
1549          * @endcode
1550          *
1551          * @return string Subpage name
1552          */
1553         public function getSubpageText() {
1554                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1555                         return $this->mTextform;
1556                 }
1557                 $parts = explode( '/', $this->mTextform );
1558                 return $parts[count( $parts ) - 1];
1559         }
1560
1561         /**
1562          * Get the title for a subpage of the current page
1563          *
1564          * @par Example:
1565          * @code
1566          * Title::newFromText('User:Foo/Bar/Baz')->getSubpage("Asdf");
1567          * # returns: Title{User:Foo/Bar/Baz/Asdf}
1568          * @endcode
1569          *
1570          * @param string $text The subpage name to add to the title
1571          * @return Title Subpage title
1572          * @since 1.20
1573          */
1574         public function getSubpage( $text ) {
1575                 return Title::makeTitleSafe( $this->getNamespace(), $this->getText() . '/' . $text );
1576         }
1577
1578         /**
1579          * Get a URL-encoded form of the subpage text
1580          *
1581          * @return string URL-encoded subpage name
1582          */
1583         public function getSubpageUrlForm() {
1584                 $text = $this->getSubpageText();
1585                 $text = wfUrlencode( str_replace( ' ', '_', $text ) );
1586                 return $text;
1587         }
1588
1589         /**
1590          * Get a URL-encoded title (not an actual URL) including interwiki
1591          *
1592          * @return string The URL-encoded form
1593          */
1594         public function getPrefixedURL() {
1595                 $s = $this->prefix( $this->mDbkeyform );
1596                 $s = wfUrlencode( str_replace( ' ', '_', $s ) );
1597                 return $s;
1598         }
1599
1600         /**
1601          * Helper to fix up the get{Canonical,Full,Link,Local,Internal}URL args
1602          * get{Canonical,Full,Link,Local,Internal}URL methods accepted an optional
1603          * second argument named variant. This was deprecated in favor
1604          * of passing an array of option with a "variant" key
1605          * Once $query2 is removed for good, this helper can be dropped
1606          * and the wfArrayToCgi moved to getLocalURL();
1607          *
1608          * @since 1.19 (r105919)
1609          * @param array|string $query
1610          * @param bool $query2
1611          * @return string
1612          */
1613         private static function fixUrlQueryArgs( $query, $query2 = false ) {
1614                 if ( $query2 !== false ) {
1615                         wfDeprecated( "Title::get{Canonical,Full,Link,Local,Internal}URL " .
1616                                 "method called with a second parameter is deprecated. Add your " .
1617                                 "parameter to an array passed as the first parameter.", "1.19" );
1618                 }
1619                 if ( is_array( $query ) ) {
1620                         $query = wfArrayToCgi( $query );
1621                 }
1622                 if ( $query2 ) {
1623                         if ( is_string( $query2 ) ) {
1624                                 // $query2 is a string, we will consider this to be
1625                                 // a deprecated $variant argument and add it to the query
1626                                 $query2 = wfArrayToCgi( array( 'variant' => $query2 ) );
1627                         } else {
1628                                 $query2 = wfArrayToCgi( $query2 );
1629                         }
1630                         // If we have $query content add a & to it first
1631                         if ( $query ) {
1632                                 $query .= '&';
1633                         }
1634                         // Now append the queries together
1635                         $query .= $query2;
1636                 }
1637                 return $query;
1638         }
1639
1640         /**
1641          * Get a real URL referring to this title, with interwiki link and
1642          * fragment
1643          *
1644          * @see self::getLocalURL for the arguments.
1645          * @see wfExpandUrl
1646          * @param array|string $query
1647          * @param bool $query2
1648          * @param string $proto Protocol type to use in URL
1649          * @return string The URL
1650          */
1651         public function getFullURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1652                 $query = self::fixUrlQueryArgs( $query, $query2 );
1653
1654                 # Hand off all the decisions on urls to getLocalURL
1655                 $url = $this->getLocalURL( $query );
1656
1657                 # Expand the url to make it a full url. Note that getLocalURL has the
1658                 # potential to output full urls for a variety of reasons, so we use
1659                 # wfExpandUrl instead of simply prepending $wgServer
1660                 $url = wfExpandUrl( $url, $proto );
1661
1662                 # Finally, add the fragment.
1663                 $url .= $this->getFragmentForURL();
1664
1665                 Hooks::run( 'GetFullURL', array( &$this, &$url, $query ) );
1666                 return $url;
1667         }
1668
1669         /**
1670          * Get a URL with no fragment or server name (relative URL) from a Title object.
1671          * If this page is generated with action=render, however,
1672          * $wgServer is prepended to make an absolute URL.
1673          *
1674          * @see self::getFullURL to always get an absolute URL.
1675          * @see self::getLinkURL to always get a URL that's the simplest URL that will be
1676          *  valid to link, locally, to the current Title.
1677          * @see self::newFromText to produce a Title object.
1678          *
1679          * @param string|array $query An optional query string,
1680          *   not used for interwiki links. Can be specified as an associative array as well,
1681          *   e.g., array( 'action' => 'edit' ) (keys and values will be URL-escaped).
1682          *   Some query patterns will trigger various shorturl path replacements.
1683          * @param array $query2 An optional secondary query array. This one MUST
1684          *   be an array. If a string is passed it will be interpreted as a deprecated
1685          *   variant argument and urlencoded into a variant= argument.
1686          *   This second query argument will be added to the $query
1687          *   The second parameter is deprecated since 1.19. Pass it as a key,value
1688          *   pair in the first parameter array instead.
1689          *
1690          * @return string String of the URL.
1691          */
1692         public function getLocalURL( $query = '', $query2 = false ) {
1693                 global $wgArticlePath, $wgScript, $wgServer, $wgRequest;
1694
1695                 $query = self::fixUrlQueryArgs( $query, $query2 );
1696
1697                 $interwiki = Interwiki::fetch( $this->mInterwiki );
1698                 if ( $interwiki ) {
1699                         $namespace = $this->getNsText();
1700                         if ( $namespace != '' ) {
1701                                 # Can this actually happen? Interwikis shouldn't be parsed.
1702                                 # Yes! It can in interwiki transclusion. But... it probably shouldn't.
1703                                 $namespace .= ':';
1704                         }
1705                         $url = $interwiki->getURL( $namespace . $this->getDBkey() );
1706                         $url = wfAppendQuery( $url, $query );
1707                 } else {
1708                         $dbkey = wfUrlencode( $this->getPrefixedDBkey() );
1709                         if ( $query == '' ) {
1710                                 $url = str_replace( '$1', $dbkey, $wgArticlePath );
1711                                 Hooks::run( 'GetLocalURL::Article', array( &$this, &$url ) );
1712                         } else {
1713                                 global $wgVariantArticlePath, $wgActionPaths, $wgContLang;
1714                                 $url = false;
1715                                 $matches = array();
1716
1717                                 if ( !empty( $wgActionPaths )
1718                                         && preg_match( '/^(.*&|)action=([^&]*)(&(.*)|)$/', $query, $matches )
1719                                 ) {
1720                                         $action = urldecode( $matches[2] );
1721                                         if ( isset( $wgActionPaths[$action] ) ) {
1722                                                 $query = $matches[1];
1723                                                 if ( isset( $matches[4] ) ) {
1724                                                         $query .= $matches[4];
1725                                                 }
1726                                                 $url = str_replace( '$1', $dbkey, $wgActionPaths[$action] );
1727                                                 if ( $query != '' ) {
1728                                                         $url = wfAppendQuery( $url, $query );
1729                                                 }
1730                                         }
1731                                 }
1732
1733                                 if ( $url === false
1734                                         && $wgVariantArticlePath
1735                                         && $wgContLang->getCode() === $this->getPageLanguage()->getCode()
1736                                         && $this->getPageLanguage()->hasVariants()
1737                                         && preg_match( '/^variant=([^&]*)$/', $query, $matches )
1738                                 ) {
1739                                         $variant = urldecode( $matches[1] );
1740                                         if ( $this->getPageLanguage()->hasVariant( $variant ) ) {
1741                                                 // Only do the variant replacement if the given variant is a valid
1742                                                 // variant for the page's language.
1743                                                 $url = str_replace( '$2', urlencode( $variant ), $wgVariantArticlePath );
1744                                                 $url = str_replace( '$1', $dbkey, $url );
1745                                         }
1746                                 }
1747
1748                                 if ( $url === false ) {
1749                                         if ( $query == '-' ) {
1750                                                 $query = '';
1751                                         }
1752                                         $url = "{$wgScript}?title={$dbkey}&{$query}";
1753                                 }
1754                         }
1755
1756                         Hooks::run( 'GetLocalURL::Internal', array( &$this, &$url, $query ) );
1757
1758                         // @todo FIXME: This causes breakage in various places when we
1759                         // actually expected a local URL and end up with dupe prefixes.
1760                         if ( $wgRequest->getVal( 'action' ) == 'render' ) {
1761                                 $url = $wgServer . $url;
1762                         }
1763                 }
1764                 Hooks::run( 'GetLocalURL', array( &$this, &$url, $query ) );
1765                 return $url;
1766         }
1767
1768         /**
1769          * Get a URL that's the simplest URL that will be valid to link, locally,
1770          * to the current Title.  It includes the fragment, but does not include
1771          * the server unless action=render is used (or the link is external).  If
1772          * there's a fragment but the prefixed text is empty, we just return a link
1773          * to the fragment.
1774          *
1775          * The result obviously should not be URL-escaped, but does need to be
1776          * HTML-escaped if it's being output in HTML.
1777          *
1778          * @param array $query
1779          * @param bool $query2
1780          * @param string $proto Protocol to use; setting this will cause a full URL to be used
1781          * @see self::getLocalURL for the arguments.
1782          * @return string The URL
1783          */
1784         public function getLinkURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1785                 if ( $this->isExternal() || $proto !== PROTO_RELATIVE ) {
1786                         $ret = $this->getFullURL( $query, $query2, $proto );
1787                 } elseif ( $this->getPrefixedText() === '' && $this->hasFragment() ) {
1788                         $ret = $this->getFragmentForURL();
1789                 } else {
1790                         $ret = $this->getLocalURL( $query, $query2 ) . $this->getFragmentForURL();
1791                 }
1792                 return $ret;
1793         }
1794
1795         /**
1796          * Get the URL form for an internal link.
1797          * - Used in various Squid-related code, in case we have a different
1798          * internal hostname for the server from the exposed one.
1799          *
1800          * This uses $wgInternalServer to qualify the path, or $wgServer
1801          * if $wgInternalServer is not set. If the server variable used is
1802          * protocol-relative, the URL will be expanded to http://
1803          *
1804          * @see self::getLocalURL for the arguments.
1805          * @return string The URL
1806          */
1807         public function getInternalURL( $query = '', $query2 = false ) {
1808                 global $wgInternalServer, $wgServer;
1809                 $query = self::fixUrlQueryArgs( $query, $query2 );
1810                 $server = $wgInternalServer !== false ? $wgInternalServer : $wgServer;
1811                 $url = wfExpandUrl( $server . $this->getLocalURL( $query ), PROTO_HTTP );
1812                 Hooks::run( 'GetInternalURL', array( &$this, &$url, $query ) );
1813                 return $url;
1814         }
1815
1816         /**
1817          * Get the URL for a canonical link, for use in things like IRC and
1818          * e-mail notifications. Uses $wgCanonicalServer and the
1819          * GetCanonicalURL hook.
1820          *
1821          * NOTE: Unlike getInternalURL(), the canonical URL includes the fragment
1822          *
1823          * @see self::getLocalURL for the arguments.
1824          * @return string The URL
1825          * @since 1.18
1826          */
1827         public function getCanonicalURL( $query = '', $query2 = false ) {
1828                 $query = self::fixUrlQueryArgs( $query, $query2 );
1829                 $url = wfExpandUrl( $this->getLocalURL( $query ) . $this->getFragmentForURL(), PROTO_CANONICAL );
1830                 Hooks::run( 'GetCanonicalURL', array( &$this, &$url, $query ) );
1831                 return $url;
1832         }
1833
1834         /**
1835          * Get the edit URL for this Title
1836          *
1837          * @return string The URL, or a null string if this is an interwiki link
1838          */
1839         public function getEditURL() {
1840                 if ( $this->isExternal() ) {
1841                         return '';
1842                 }
1843                 $s = $this->getLocalURL( 'action=edit' );
1844
1845                 return $s;
1846         }
1847
1848         /**
1849          * Is $wgUser watching this page?
1850          *
1851          * @deprecated since 1.20; use User::isWatched() instead.
1852          * @return bool
1853          */
1854         public function userIsWatching() {
1855                 global $wgUser;
1856
1857                 if ( is_null( $this->mWatched ) ) {
1858                         if ( NS_SPECIAL == $this->mNamespace || !$wgUser->isLoggedIn() ) {
1859                                 $this->mWatched = false;
1860                         } else {
1861                                 $this->mWatched = $wgUser->isWatched( $this );
1862                         }
1863                 }
1864                 return $this->mWatched;
1865         }
1866
1867         /**
1868          * Can $user perform $action on this page?
1869          * This skips potentially expensive cascading permission checks
1870          * as well as avoids expensive error formatting
1871          *
1872          * Suitable for use for nonessential UI controls in common cases, but
1873          * _not_ for functional access control.
1874          *
1875          * May provide false positives, but should never provide a false negative.
1876          *
1877          * @param string $action Action that permission needs to be checked for
1878          * @param User $user User to check (since 1.19); $wgUser will be used if not provided.
1879          * @return bool
1880          */
1881         public function quickUserCan( $action, $user = null ) {
1882                 return $this->userCan( $action, $user, false );
1883         }
1884
1885         /**
1886          * Can $user perform $action on this page?
1887          *
1888          * @param string $action Action that permission needs to be checked for
1889          * @param User $user User to check (since 1.19); $wgUser will be used if not
1890          *   provided.
1891          * @param bool $doExpensiveQueries Set this to false to avoid doing
1892          *   unnecessary queries.
1893          * @return bool
1894          */
1895         public function userCan( $action, $user = null, $doExpensiveQueries = true ) {
1896                 if ( !$user instanceof User ) {
1897                         global $wgUser;
1898                         $user = $wgUser;
1899                 }
1900
1901                 return !count( $this->getUserPermissionsErrorsInternal(
1902                         $action, $user, $doExpensiveQueries, true ) );
1903         }
1904
1905         /**
1906          * Can $user perform $action on this page?
1907          *
1908          * @todo FIXME: This *does not* check throttles (User::pingLimiter()).
1909          *
1910          * @param string $action Action that permission needs to be checked for
1911          * @param User $user User to check
1912          * @param bool $doExpensiveQueries Set this to false to avoid doing unnecessary
1913          *   queries by skipping checks for cascading protections and user blocks.
1914          * @param array $ignoreErrors Array of Strings Set this to a list of message keys
1915          *   whose corresponding errors may be ignored.
1916          * @return array Array of arguments to wfMessage to explain permissions problems.
1917          */
1918         public function getUserPermissionsErrors( $action, $user, $doExpensiveQueries = true,
1919                 $ignoreErrors = array()
1920         ) {
1921                 $errors = $this->getUserPermissionsErrorsInternal( $action, $user, $doExpensiveQueries );
1922
1923                 // Remove the errors being ignored.
1924                 foreach ( $errors as $index => $error ) {
1925                         $error_key = is_array( $error ) ? $error[0] : $error;
1926
1927                         if ( in_array( $error_key, $ignoreErrors ) ) {
1928                                 unset( $errors[$index] );
1929                         }
1930                 }
1931
1932                 return $errors;
1933         }
1934
1935         /**
1936          * Permissions checks that fail most often, and which are easiest to test.
1937          *
1938          * @param string $action The action to check
1939          * @param User $user User to check
1940          * @param array $errors List of current errors
1941          * @param bool $doExpensiveQueries Whether or not to perform expensive queries
1942          * @param bool $short Short circuit on first error
1943          *
1944          * @return array List of errors
1945          */
1946         private function checkQuickPermissions( $action, $user, $errors,
1947                 $doExpensiveQueries, $short
1948         ) {
1949                 if ( !Hooks::run( 'TitleQuickPermissions',
1950                         array( $this, $user, $action, &$errors, $doExpensiveQueries, $short ) )
1951                 ) {
1952                         return $errors;
1953                 }
1954
1955                 if ( $action == 'create' ) {
1956                         if (
1957                                 ( $this->isTalkPage() && !$user->isAllowed( 'createtalk' ) ) ||
1958                                 ( !$this->isTalkPage() && !$user->isAllowed( 'createpage' ) )
1959                         ) {
1960                                 $errors[] = $user->isAnon() ? array( 'nocreatetext' ) : array( 'nocreate-loggedin' );
1961                         }
1962                 } elseif ( $action == 'move' ) {
1963                         if ( !$user->isAllowed( 'move-rootuserpages' )
1964                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
1965                                 // Show user page-specific message only if the user can move other pages
1966                                 $errors[] = array( 'cant-move-user-page' );
1967                         }
1968
1969                         // Check if user is allowed to move files if it's a file
1970                         if ( $this->mNamespace == NS_FILE && !$user->isAllowed( 'movefile' ) ) {
1971                                 $errors[] = array( 'movenotallowedfile' );
1972                         }
1973
1974                         // Check if user is allowed to move category pages if it's a category page
1975                         if ( $this->mNamespace == NS_CATEGORY && !$user->isAllowed( 'move-categorypages' ) ) {
1976                                 $errors[] = array( 'cant-move-category-page' );
1977                         }
1978
1979                         if ( !$user->isAllowed( 'move' ) ) {
1980                                 // User can't move anything
1981                                 $userCanMove = User::groupHasPermission( 'user', 'move' );
1982                                 $autoconfirmedCanMove = User::groupHasPermission( 'autoconfirmed', 'move' );
1983                                 if ( $user->isAnon() && ( $userCanMove || $autoconfirmedCanMove ) ) {
1984                                         // custom message if logged-in users without any special rights can move
1985                                         $errors[] = array( 'movenologintext' );
1986                                 } else {
1987                                         $errors[] = array( 'movenotallowed' );
1988                                 }
1989                         }
1990                 } elseif ( $action == 'move-target' ) {
1991                         if ( !$user->isAllowed( 'move' ) ) {
1992                                 // User can't move anything
1993                                 $errors[] = array( 'movenotallowed' );
1994                         } elseif ( !$user->isAllowed( 'move-rootuserpages' )
1995                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
1996                                 // Show user page-specific message only if the user can move other pages
1997                                 $errors[] = array( 'cant-move-to-user-page' );
1998                         } elseif ( !$user->isAllowed( 'move-categorypages' )
1999                                         && $this->mNamespace == NS_CATEGORY ) {
2000                                 // Show category page-specific message only if the user can move other pages
2001                                 $errors[] = array( 'cant-move-to-category-page' );
2002                         }
2003                 } elseif ( !$user->isAllowed( $action ) ) {
2004                         $errors[] = $this->missingPermissionError( $action, $short );
2005                 }
2006
2007                 return $errors;
2008         }
2009
2010         /**
2011          * Add the resulting error code to the errors array
2012          *
2013          * @param array $errors List of current errors
2014          * @param array $result Result of errors
2015          *
2016          * @return array List of errors
2017          */
2018         private function resultToError( $errors, $result ) {
2019                 if ( is_array( $result ) && count( $result ) && !is_array( $result[0] ) ) {
2020                         // A single array representing an error
2021                         $errors[] = $result;
2022                 } elseif ( is_array( $result ) && is_array( $result[0] ) ) {
2023                         // A nested array representing multiple errors
2024                         $errors = array_merge( $errors, $result );
2025                 } elseif ( $result !== '' && is_string( $result ) ) {
2026                         // A string representing a message-id
2027                         $errors[] = array( $result );
2028                 } elseif ( $result === false ) {
2029                         // a generic "We don't want them to do that"
2030                         $errors[] = array( 'badaccess-group0' );
2031                 }
2032                 return $errors;
2033         }
2034
2035         /**
2036          * Check various permission hooks
2037          *
2038          * @param string $action The action to check
2039          * @param User $user User to check
2040          * @param array $errors List of current errors
2041          * @param bool $doExpensiveQueries Whether or not to perform expensive queries
2042          * @param bool $short Short circuit on first error
2043          *
2044          * @return array List of errors
2045          */
2046         private function checkPermissionHooks( $action, $user, $errors, $doExpensiveQueries, $short ) {
2047                 // Use getUserPermissionsErrors instead
2048                 $result = '';
2049                 if ( !Hooks::run( 'userCan', array( &$this, &$user, $action, &$result ) ) ) {
2050                         return $result ? array() : array( array( 'badaccess-group0' ) );
2051                 }
2052                 // Check getUserPermissionsErrors hook
2053                 if ( !Hooks::run( 'getUserPermissionsErrors', array( &$this, &$user, $action, &$result ) ) ) {
2054                         $errors = $this->resultToError( $errors, $result );
2055                 }
2056                 // Check getUserPermissionsErrorsExpensive hook
2057                 if (
2058                         $doExpensiveQueries
2059                         && !( $short && count( $errors ) > 0 )
2060                         && !Hooks::run( 'getUserPermissionsErrorsExpensive', array( &$this, &$user, $action, &$result ) )
2061                 ) {
2062                         $errors = $this->resultToError( $errors, $result );
2063                 }
2064
2065                 return $errors;
2066         }
2067
2068         /**
2069          * Check permissions on special pages & namespaces
2070          *
2071          * @param string $action The action to check
2072          * @param User $user User to check
2073          * @param array $errors List of current errors
2074          * @param bool $doExpensiveQueries Whether or not to perform expensive queries
2075          * @param bool $short Short circuit on first error
2076          *
2077          * @return array List of errors
2078          */
2079         private function checkSpecialsAndNSPermissions( $action, $user, $errors,
2080                 $doExpensiveQueries, $short
2081         ) {
2082                 # Only 'createaccount' can be performed on special pages,
2083                 # which don't actually exist in the DB.
2084                 if ( NS_SPECIAL == $this->mNamespace && $action !== 'createaccount' ) {
2085                         $errors[] = array( 'ns-specialprotected' );
2086                 }
2087
2088                 # Check $wgNamespaceProtection for restricted namespaces
2089                 if ( $this->isNamespaceProtected( $user ) ) {
2090                         $ns = $this->mNamespace == NS_MAIN ?
2091                                 wfMessage( 'nstab-main' )->text() : $this->getNsText();
2092                         $errors[] = $this->mNamespace == NS_MEDIAWIKI ?
2093                                 array( 'protectedinterface', $action ) : array( 'namespaceprotected', $ns, $action );
2094                 }
2095
2096                 return $errors;
2097         }
2098
2099         /**
2100          * Check CSS/JS sub-page permissions
2101          *
2102          * @param string $action The action to check
2103          * @param User $user User to check
2104          * @param array $errors List of current errors
2105          * @param bool $doExpensiveQueries Whether or not to perform expensive queries
2106          * @param bool $short Short circuit on first error
2107          *
2108          * @return array List of errors
2109          */
2110         private function checkCSSandJSPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
2111                 # Protect css/js subpages of user pages
2112                 # XXX: this might be better using restrictions
2113                 # XXX: right 'editusercssjs' is deprecated, for backward compatibility only
2114                 if ( $action != 'patrol' && !$user->isAllowed( 'editusercssjs' ) ) {
2115                         if ( preg_match( '/^' . preg_quote( $user->getName(), '/' ) . '\//', $this->mTextform ) ) {
2116                                 if ( $this->isCssSubpage() && !$user->isAllowedAny( 'editmyusercss', 'editusercss' ) ) {
2117                                         $errors[] = array( 'mycustomcssprotected', $action );
2118                                 } elseif ( $this->isJsSubpage() && !$user->isAllowedAny( 'editmyuserjs', 'edituserjs' ) ) {
2119                                         $errors[] = array( 'mycustomjsprotected', $action );
2120                                 }
2121                         } else {
2122                                 if ( $this->isCssSubpage() && !$user->isAllowed( 'editusercss' ) ) {
2123                                         $errors[] = array( 'customcssprotected', $action );
2124                                 } elseif ( $this->isJsSubpage() && !$user->isAllowed( 'edituserjs' ) ) {
2125                                         $errors[] = array( 'customjsprotected', $action );
2126                                 }
2127                         }
2128                 }
2129
2130                 return $errors;
2131         }
2132
2133         /**
2134          * Check against page_restrictions table requirements on this
2135          * page. The user must possess all required rights for this
2136          * action.
2137          *
2138          * @param string $action The action to check
2139          * @param User $user User to check
2140          * @param array $errors List of current errors
2141          * @param bool $doExpensiveQueries Whether or not to perform expensive queries
2142          * @param bool $short Short circuit on first error
2143          *
2144          * @return array List of errors
2145          */
2146         private function checkPageRestrictions( $action, $user, $errors, $doExpensiveQueries, $short ) {
2147                 foreach ( $this->getRestrictions( $action ) as $right ) {
2148                         // Backwards compatibility, rewrite sysop -> editprotected
2149                         if ( $right == 'sysop' ) {
2150                                 $right = 'editprotected';
2151                         }
2152                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2153                         if ( $right == 'autoconfirmed' ) {
2154                                 $right = 'editsemiprotected';
2155                         }
2156                         if ( $right == '' ) {
2157                                 continue;
2158                         }
2159                         if ( !$user->isAllowed( $right ) ) {
2160                                 $errors[] = array( 'protectedpagetext', $right, $action );
2161                         } elseif ( $this->mCascadeRestriction && !$user->isAllowed( 'protect' ) ) {
2162                                 $errors[] = array( 'protectedpagetext', 'protect', $action );
2163                         }
2164                 }
2165
2166                 return $errors;
2167         }
2168
2169         /**
2170          * Check restrictions on cascading pages.
2171          *
2172          * @param string $action The action to check
2173          * @param User $user User to check
2174          * @param array $errors List of current errors
2175          * @param bool $doExpensiveQueries Whether or not to perform expensive queries
2176          * @param bool $short Short circuit on first error
2177          *
2178          * @return array List of errors
2179          */
2180         private function checkCascadingSourcesRestrictions( $action, $user, $errors,
2181                 $doExpensiveQueries, $short
2182         ) {
2183                 if ( $doExpensiveQueries && !$this->isCssJsSubpage() ) {
2184                         # We /could/ use the protection level on the source page, but it's
2185                         # fairly ugly as we have to establish a precedence hierarchy for pages
2186                         # included by multiple cascade-protected pages. So just restrict
2187                         # it to people with 'protect' permission, as they could remove the
2188                         # protection anyway.
2189                         list( $cascadingSources, $restrictions ) = $this->getCascadeProtectionSources();
2190                         # Cascading protection depends on more than this page...
2191                         # Several cascading protected pages may include this page...
2192                         # Check each cascading level
2193                         # This is only for protection restrictions, not for all actions
2194                         if ( isset( $restrictions[$action] ) ) {
2195                                 foreach ( $restrictions[$action] as $right ) {
2196                                         // Backwards compatibility, rewrite sysop -> editprotected
2197                                         if ( $right == 'sysop' ) {
2198                                                 $right = 'editprotected';
2199                                         }
2200                                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2201                                         if ( $right == 'autoconfirmed' ) {
2202                                                 $right = 'editsemiprotected';
2203                                         }
2204                                         if ( $right != '' && !$user->isAllowedAll( 'protect', $right ) ) {
2205                                                 $pages = '';
2206                                                 foreach ( $cascadingSources as $page ) {
2207                                                         $pages .= '* [[:' . $page->getPrefixedText() . "]]\n";
2208                                                 }
2209                                                 $errors[] = array( 'cascadeprotected', count( $cascadingSources ), $pages, $action );
2210                                         }
2211                                 }
2212                         }
2213                 }
2214
2215                 return $errors;
2216         }
2217
2218         /**
2219          * Check action permissions not already checked in checkQuickPermissions
2220          *
2221          * @param string $action The action to check
2222          * @param User $user User to check
2223          * @param array $errors List of current errors
2224          * @param bool $doExpensiveQueries Whether or not to perform expensive queries
2225          * @param bool $short Short circuit on first error
2226          *
2227          * @return array List of errors
2228          */
2229         private function checkActionPermissions( $action, $user, $errors,
2230                 $doExpensiveQueries, $short
2231         ) {
2232                 global $wgDeleteRevisionsLimit, $wgLang;
2233
2234                 if ( $action == 'protect' ) {
2235                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit',
2236                                 $user, $doExpensiveQueries, true ) )
2237                         ) {
2238                                 // If they can't edit, they shouldn't protect.
2239                                 $errors[] = array( 'protect-cantedit' );
2240                         }
2241                 } elseif ( $action == 'create' ) {
2242                         $title_protection = $this->getTitleProtection();
2243                         if ( $title_protection ) {
2244                                 if ( $title_protection['permission'] == ''
2245                                         || !$user->isAllowed( $title_protection['permission'] )
2246                                 ) {
2247                                         $errors[] = array(
2248                                                 'titleprotected',
2249                                                 User::whoIs( $title_protection['user'] ),
2250                                                 $title_protection['reason']
2251                                         );
2252                                 }
2253                         }
2254                 } elseif ( $action == 'move' ) {
2255                         // Check for immobile pages
2256                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2257                                 // Specific message for this case
2258                                 $errors[] = array( 'immobile-source-namespace', $this->getNsText() );
2259                         } elseif ( !$this->isMovable() ) {
2260                                 // Less specific message for rarer cases
2261                                 $errors[] = array( 'immobile-source-page' );
2262                         }
2263                 } elseif ( $action == 'move-target' ) {
2264                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2265                                 $errors[] = array( 'immobile-target-namespace', $this->getNsText() );
2266                         } elseif ( !$this->isMovable() ) {
2267                                 $errors[] = array( 'immobile-target-page' );
2268                         }
2269                 } elseif ( $action == 'delete' ) {
2270                         $tempErrors = $this->checkPageRestrictions( 'edit',
2271                                 $user, array(), $doExpensiveQueries, true );
2272                         if ( !$tempErrors ) {
2273                                 $tempErrors = $this->checkCascadingSourcesRestrictions( 'edit',
2274                                         $user, $tempErrors, $doExpensiveQueries, true );
2275                         }
2276                         if ( $tempErrors ) {
2277                                 // If protection keeps them from editing, they shouldn't be able to delete.
2278                                 $errors[] = array( 'deleteprotected' );
2279                         }
2280                         if ( $doExpensiveQueries && $wgDeleteRevisionsLimit
2281                                 && !$this->userCan( 'bigdelete', $user ) && $this->isBigDeletion()
2282                         ) {
2283                                 $errors[] = array( 'delete-toobig', $wgLang->formatNum( $wgDeleteRevisionsLimit ) );
2284                         }
2285                 }
2286                 return $errors;
2287         }
2288
2289         /**
2290          * Check that the user isn't blocked from editing.
2291          *
2292          * @param string $action The action to check
2293          * @param User $user User to check
2294          * @param array $errors List of current errors
2295          * @param bool $doExpensiveQueries Whether or not to perform expensive queries
2296          * @param bool $short Short circuit on first error
2297          *
2298          * @return array List of errors
2299          */
2300         private function checkUserBlock( $action, $user, $errors, $doExpensiveQueries, $short ) {
2301                 // Account creation blocks handled at userlogin.
2302                 // Unblocking handled in SpecialUnblock
2303                 if ( !$doExpensiveQueries || in_array( $action, array( 'createaccount', 'unblock' ) ) ) {
2304                         return $errors;
2305                 }
2306
2307                 global $wgEmailConfirmToEdit;
2308
2309                 if ( $wgEmailConfirmToEdit && !$user->isEmailConfirmed() ) {
2310                         $errors[] = array( 'confirmedittext' );
2311                 }
2312
2313                 if ( ( $action == 'edit' || $action == 'create' ) && !$user->isBlockedFrom( $this ) ) {
2314                         // Don't block the user from editing their own talk page unless they've been
2315                         // explicitly blocked from that too.
2316                 } elseif ( $user->isBlocked() && $user->mBlock->prevents( $action ) !== false ) {
2317                         // @todo FIXME: Pass the relevant context into this function.
2318                         $errors[] = $user->getBlock()->getPermissionsError( RequestContext::getMain() );
2319                 }
2320
2321                 return $errors;
2322         }
2323
2324         /**
2325          * Check that the user is allowed to read this page.
2326          *
2327          * @param string $action The action to check
2328          * @param User $user User to check
2329          * @param array $errors List of current errors
2330          * @param bool $doExpensiveQueries Whether or not to perform expensive queries
2331          * @param bool $short Short circuit on first error
2332          *
2333          * @return array List of errors
2334          */
2335         private function checkReadPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
2336                 global $wgWhitelistRead, $wgWhitelistReadRegexp;
2337
2338                 $whitelisted = false;
2339                 if ( User::isEveryoneAllowed( 'read' ) ) {
2340                         # Shortcut for public wikis, allows skipping quite a bit of code
2341                         $whitelisted = true;
2342                 } elseif ( $user->isAllowed( 'read' ) ) {
2343                         # If the user is allowed to read pages, he is allowed to read all pages
2344                         $whitelisted = true;
2345                 } elseif ( $this->isSpecial( 'Userlogin' )
2346                         || $this->isSpecial( 'ChangePassword' )
2347                         || $this->isSpecial( 'PasswordReset' )
2348                 ) {
2349                         # Always grant access to the login page.
2350                         # Even anons need to be able to log in.
2351                         $whitelisted = true;
2352                 } elseif ( is_array( $wgWhitelistRead ) && count( $wgWhitelistRead ) ) {
2353                         # Time to check the whitelist
2354                         # Only do these checks is there's something to check against
2355                         $name = $this->getPrefixedText();
2356                         $dbName = $this->getPrefixedDBkey();
2357
2358                         // Check for explicit whitelisting with and without underscores
2359                         if ( in_array( $name, $wgWhitelistRead, true ) || in_array( $dbName, $wgWhitelistRead, true ) ) {
2360                                 $whitelisted = true;
2361                         } elseif ( $this->getNamespace() == NS_MAIN ) {
2362                                 # Old settings might have the title prefixed with
2363                                 # a colon for main-namespace pages
2364                                 if ( in_array( ':' . $name, $wgWhitelistRead ) ) {
2365                                         $whitelisted = true;
2366                                 }
2367                         } elseif ( $this->isSpecialPage() ) {
2368                                 # If it's a special page, ditch the subpage bit and check again
2369                                 $name = $this->getDBkey();
2370                                 list( $name, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $name );
2371                                 if ( $name ) {
2372                                         $pure = SpecialPage::getTitleFor( $name )->getPrefixedText();
2373                                         if ( in_array( $pure, $wgWhitelistRead, true ) ) {
2374                                                 $whitelisted = true;
2375                                         }
2376                                 }
2377                         }
2378                 }
2379
2380                 if ( !$whitelisted && is_array( $wgWhitelistReadRegexp ) && !empty( $wgWhitelistReadRegexp ) ) {
2381                         $name = $this->getPrefixedText();
2382                         // Check for regex whitelisting
2383                         foreach ( $wgWhitelistReadRegexp as $listItem ) {
2384                                 if ( preg_match( $listItem, $name ) ) {
2385                                         $whitelisted = true;
2386                                         break;
2387                                 }
2388                         }
2389                 }
2390
2391                 if ( !$whitelisted ) {
2392                         # If the title is not whitelisted, give extensions a chance to do so...
2393                         Hooks::run( 'TitleReadWhitelist', array( $this, $user, &$whitelisted ) );
2394                         if ( !$whitelisted ) {
2395                                 $errors[] = $this->missingPermissionError( $action, $short );
2396                         }
2397                 }
2398
2399                 return $errors;
2400         }
2401
2402         /**
2403          * Get a description array when the user doesn't have the right to perform
2404          * $action (i.e. when User::isAllowed() returns false)
2405          *
2406          * @param string $action The action to check
2407          * @param bool $short Short circuit on first error
2408          * @return array List of errors
2409          */
2410         private function missingPermissionError( $action, $short ) {
2411                 // We avoid expensive display logic for quickUserCan's and such
2412                 if ( $short ) {
2413                         return array( 'badaccess-group0' );
2414                 }
2415
2416                 $groups = array_map( array( 'User', 'makeGroupLinkWiki' ),
2417                         User::getGroupsWithPermission( $action ) );
2418
2419                 if ( count( $groups ) ) {
2420                         global $wgLang;
2421                         return array(
2422                                 'badaccess-groups',
2423                                 $wgLang->commaList( $groups ),
2424                                 count( $groups )
2425                         );
2426                 } else {
2427                         return array( 'badaccess-group0' );
2428                 }
2429         }
2430
2431         /**
2432          * Can $user perform $action on this page? This is an internal function,
2433          * which checks ONLY that previously checked by userCan (i.e. it leaves out
2434          * checks on wfReadOnly() and blocks)
2435          *
2436          * @param string $action Action that permission needs to be checked for
2437          * @param User $user User to check
2438          * @param bool $doExpensiveQueries Set this to false to avoid doing unnecessary queries.
2439          * @param bool $short Set this to true to stop after the first permission error.
2440          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
2441          */
2442         protected function getUserPermissionsErrorsInternal( $action, $user,
2443                 $doExpensiveQueries = true, $short = false
2444         ) {
2445
2446                 # Read has special handling
2447                 if ( $action == 'read' ) {
2448                         $checks = array(
2449                                 'checkPermissionHooks',
2450                                 'checkReadPermissions',
2451                         );
2452                 # Don't call checkSpecialsAndNSPermissions or checkCSSandJSPermissions
2453                 # here as it will lead to duplicate error messages. This is okay to do
2454                 # since anywhere that checks for create will also check for edit, and
2455                 # those checks are called for edit.
2456                 } elseif ( $action == 'create' ) {
2457                         $checks = array(
2458                                 'checkQuickPermissions',
2459                                 'checkPermissionHooks',
2460                                 'checkPageRestrictions',
2461                                 'checkCascadingSourcesRestrictions',
2462                                 'checkActionPermissions',
2463                                 'checkUserBlock'
2464                         );
2465                 } else {
2466                         $checks = array(
2467                                 'checkQuickPermissions',
2468                                 'checkPermissionHooks',
2469                                 'checkSpecialsAndNSPermissions',
2470                                 'checkCSSandJSPermissions',
2471                                 'checkPageRestrictions',
2472                                 'checkCascadingSourcesRestrictions',
2473                                 'checkActionPermissions',
2474                                 'checkUserBlock'
2475                         );
2476                 }
2477
2478                 $errors = array();
2479                 while ( count( $checks ) > 0 &&
2480                                 !( $short && count( $errors ) > 0 ) ) {
2481                         $method = array_shift( $checks );
2482                         $errors = $this->$method( $action, $user, $errors, $doExpensiveQueries, $short );
2483                 }
2484
2485                 return $errors;
2486         }
2487
2488         /**
2489          * Get a filtered list of all restriction types supported by this wiki.
2490          * @param bool $exists True to get all restriction types that apply to
2491          * titles that do exist, False for all restriction types that apply to
2492          * titles that do not exist
2493          * @return array
2494          */
2495         public static function getFilteredRestrictionTypes( $exists = true ) {
2496                 global $wgRestrictionTypes;
2497                 $types = $wgRestrictionTypes;
2498                 if ( $exists ) {
2499                         # Remove the create restriction for existing titles
2500                         $types = array_diff( $types, array( 'create' ) );
2501                 } else {
2502                         # Only the create and upload restrictions apply to non-existing titles
2503                         $types = array_intersect( $types, array( 'create', 'upload' ) );
2504                 }
2505                 return $types;
2506         }
2507
2508         /**
2509          * Returns restriction types for the current Title
2510          *
2511          * @return array Applicable restriction types
2512          */
2513         public function getRestrictionTypes() {
2514                 if ( $this->isSpecialPage() ) {
2515                         return array();
2516                 }
2517
2518                 $types = self::getFilteredRestrictionTypes( $this->exists() );
2519
2520                 if ( $this->getNamespace() != NS_FILE ) {
2521                         # Remove the upload restriction for non-file titles
2522                         $types = array_diff( $types, array( 'upload' ) );
2523                 }
2524
2525                 Hooks::run( 'TitleGetRestrictionTypes', array( $this, &$types ) );
2526
2527                 wfDebug( __METHOD__ . ': applicable restrictions to [[' .
2528                         $this->getPrefixedText() . ']] are {' . implode( ',', $types ) . "}\n" );
2529
2530                 return $types;
2531         }
2532
2533         /**
2534          * Is this title subject to title protection?
2535          * Title protection is the one applied against creation of such title.
2536          *
2537          * @return array|bool An associative array representing any existent title
2538          *   protection, or false if there's none.
2539          */
2540         public function getTitleProtection() {
2541                 // Can't protect pages in special namespaces
2542                 if ( $this->getNamespace() < 0 ) {
2543                         return false;
2544                 }
2545
2546                 // Can't protect pages that exist.
2547                 if ( $this->exists() ) {
2548                         return false;
2549                 }
2550
2551                 if ( $this->mTitleProtection === null ) {
2552                         $dbr = wfGetDB( DB_SLAVE );
2553                         $res = $dbr->select(
2554                                 'protected_titles',
2555                                 array(
2556                                         'user' => 'pt_user',
2557                                         'reason' => 'pt_reason',
2558                                         'expiry' => 'pt_expiry',
2559                                         'permission' => 'pt_create_perm'
2560                                 ),
2561                                 array( 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ),
2562                                 __METHOD__
2563                         );
2564
2565                         // fetchRow returns false if there are no rows.
2566                         $row = $dbr->fetchRow( $res );
2567                         if ( $row ) {
2568                                 if ( $row['permission'] == 'sysop' ) {
2569                                         $row['permission'] = 'editprotected'; // B/C
2570                                 }
2571                                 if ( $row['permission'] == 'autoconfirmed' ) {
2572                                         $row['permission'] = 'editsemiprotected'; // B/C
2573                                 }
2574                         }
2575                         $this->mTitleProtection = $row;
2576                 }
2577                 return $this->mTitleProtection;
2578         }
2579
2580         /**
2581          * Remove any title protection due to page existing
2582          */
2583         public function deleteTitleProtection() {
2584                 $dbw = wfGetDB( DB_MASTER );
2585
2586                 $dbw->delete(
2587                         'protected_titles',
2588                         array( 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ),
2589                         __METHOD__
2590                 );
2591                 $this->mTitleProtection = false;
2592         }
2593
2594         /**
2595          * Is this page "semi-protected" - the *only* protection levels are listed
2596          * in $wgSemiprotectedRestrictionLevels?
2597          *
2598          * @param string $action Action to check (default: edit)
2599          * @return bool
2600          */
2601         public function isSemiProtected( $action = 'edit' ) {
2602                 global $wgSemiprotectedRestrictionLevels;
2603
2604                 $restrictions = $this->getRestrictions( $action );
2605                 $semi = $wgSemiprotectedRestrictionLevels;
2606                 if ( !$restrictions || !$semi ) {
2607                         // Not protected, or all protection is full protection
2608                         return false;
2609                 }
2610
2611                 // Remap autoconfirmed to editsemiprotected for BC
2612                 foreach ( array_keys( $semi, 'autoconfirmed' ) as $key ) {
2613                         $semi[$key] = 'editsemiprotected';
2614                 }
2615                 foreach ( array_keys( $restrictions, 'autoconfirmed' ) as $key ) {
2616                         $restrictions[$key] = 'editsemiprotected';
2617                 }
2618
2619                 return !array_diff( $restrictions, $semi );
2620         }
2621
2622         /**
2623          * Does the title correspond to a protected article?
2624          *
2625          * @param string $action The action the page is protected from,
2626          * by default checks all actions.
2627          * @return bool
2628          */
2629         public function isProtected( $action = '' ) {
2630                 global $wgRestrictionLevels;
2631
2632                 $restrictionTypes = $this->getRestrictionTypes();
2633
2634                 # Special pages have inherent protection
2635                 if ( $this->isSpecialPage() ) {
2636                         return true;
2637                 }
2638
2639                 # Check regular protection levels
2640                 foreach ( $restrictionTypes as $type ) {
2641                         if ( $action == $type || $action == '' ) {
2642                                 $r = $this->getRestrictions( $type );
2643                                 foreach ( $wgRestrictionLevels as $level ) {
2644                                         if ( in_array( $level, $r ) && $level != '' ) {
2645                                                 return true;
2646                                         }
2647                                 }
2648                         }
2649                 }
2650
2651                 return false;
2652         }
2653
2654         /**
2655          * Determines if $user is unable to edit this page because it has been protected
2656          * by $wgNamespaceProtection.
2657          *
2658          * @param User $user User object to check permissions
2659          * @return bool
2660          */
2661         public function isNamespaceProtected( User $user ) {
2662                 global $wgNamespaceProtection;
2663
2664                 if ( isset( $wgNamespaceProtection[$this->mNamespace] ) ) {
2665                         foreach ( (array)$wgNamespaceProtection[$this->mNamespace] as $right ) {
2666                                 if ( $right != '' && !$user->isAllowed( $right ) ) {
2667                                         return true;
2668                                 }
2669                         }
2670                 }
2671                 return false;
2672         }
2673
2674         /**
2675          * Cascading protection: Return true if cascading restrictions apply to this page, false if not.
2676          *
2677          * @return bool If the page is subject to cascading restrictions.
2678          */
2679         public function isCascadeProtected() {
2680                 list( $sources, /* $restrictions */ ) = $this->getCascadeProtectionSources( false );
2681                 return ( $sources > 0 );
2682         }
2683
2684         /**
2685          * Determines whether cascading protection sources have already been loaded from
2686          * the database.
2687          *
2688          * @param bool $getPages True to check if the pages are loaded, or false to check
2689          * if the status is loaded.
2690          * @return bool Whether or not the specified information has been loaded
2691          * @since 1.23
2692          */
2693         public function areCascadeProtectionSourcesLoaded( $getPages = true ) {
2694                 return $getPages ? $this->mCascadeSources !== null : $this->mHasCascadingRestrictions !== null;
2695         }
2696
2697         /**
2698          * Cascading protection: Get the source of any cascading restrictions on this page.
2699          *
2700          * @param bool $getPages Whether or not to retrieve the actual pages
2701          *        that the restrictions have come from and the actual restrictions
2702          *        themselves.
2703          * @return array Two elements: First is an array of Title objects of the
2704          *        pages from which cascading restrictions have come, false for
2705          *        none, or true if such restrictions exist but $getPages was not
2706          *        set. Second is an array like that returned by
2707          *        Title::getAllRestrictions(), or an empty array if $getPages is
2708          *        false.
2709          */
2710         public function getCascadeProtectionSources( $getPages = true ) {
2711                 global $wgContLang;
2712                 $pagerestrictions = array();
2713
2714                 if ( $this->mCascadeSources !== null && $getPages ) {
2715                         return array( $this->mCascadeSources, $this->mCascadingRestrictions );
2716                 } elseif ( $this->mHasCascadingRestrictions !== null && !$getPages ) {
2717                         return array( $this->mHasCascadingRestrictions, $pagerestrictions );
2718                 }
2719
2720                 $dbr = wfGetDB( DB_SLAVE );
2721
2722                 if ( $this->getNamespace() == NS_FILE ) {
2723                         $tables = array( 'imagelinks', 'page_restrictions' );
2724                         $where_clauses = array(
2725                                 'il_to' => $this->getDBkey(),
2726                                 'il_from=pr_page',
2727                                 'pr_cascade' => 1
2728                         );
2729                 } else {
2730                         $tables = array( 'templatelinks', 'page_restrictions' );
2731                         $where_clauses = array(
2732                                 'tl_namespace' => $this->getNamespace(),
2733                                 'tl_title' => $this->getDBkey(),
2734                                 'tl_from=pr_page',
2735                                 'pr_cascade' => 1
2736                         );
2737                 }
2738
2739                 if ( $getPages ) {
2740                         $cols = array( 'pr_page', 'page_namespace', 'page_title',
2741                                 'pr_expiry', 'pr_type', 'pr_level' );
2742                         $where_clauses[] = 'page_id=pr_page';
2743                         $tables[] = 'page';
2744                 } else {
2745                         $cols = array( 'pr_expiry' );
2746                 }
2747
2748                 $res = $dbr->select( $tables, $cols, $where_clauses, __METHOD__ );
2749
2750                 $sources = $getPages ? array() : false;
2751                 $now = wfTimestampNow();
2752                 $purgeExpired = false;
2753
2754                 foreach ( $res as $row ) {
2755                         $expiry = $wgContLang->formatExpiry( $row->pr_expiry, TS_MW );
2756                         if ( $expiry > $now ) {
2757                                 if ( $getPages ) {
2758                                         $page_id = $row->pr_page;
2759                                         $page_ns = $row->page_namespace;
2760                                         $page_title = $row->page_title;
2761                                         $sources[$page_id] = Title::makeTitle( $page_ns, $page_title );
2762                                         # Add groups needed for each restriction type if its not already there
2763                                         # Make sure this restriction type still exists
2764
2765                                         if ( !isset( $pagerestrictions[$row->pr_type] ) ) {
2766                                                 $pagerestrictions[$row->pr_type] = array();
2767                                         }
2768
2769                                         if (
2770                                                 isset( $pagerestrictions[$row->pr_type] )
2771                                                 && !in_array( $row->pr_level, $pagerestrictions[$row->pr_type] )
2772                                         ) {
2773                                                 $pagerestrictions[$row->pr_type][] = $row->pr_level;
2774                                         }
2775                                 } else {
2776                                         $sources = true;
2777                                 }
2778                         } else {
2779                                 // Trigger lazy purge of expired restrictions from the db
2780                                 $purgeExpired = true;
2781                         }
2782                 }
2783                 if ( $purgeExpired ) {
2784                         Title::purgeExpiredRestrictions();
2785                 }
2786
2787                 if ( $getPages ) {
2788                         $this->mCascadeSources = $sources;
2789                         $this->mCascadingRestrictions = $pagerestrictions;
2790                 } else {
2791                         $this->mHasCascadingRestrictions = $sources;
2792                 }
2793
2794                 return array( $sources, $pagerestrictions );
2795         }
2796
2797         /**
2798          * Accessor for mRestrictionsLoaded
2799          *
2800          * @return bool Whether or not the page's restrictions have already been
2801          * loaded from the database
2802          * @since 1.23
2803          */
2804         public function areRestrictionsLoaded() {
2805                 return $this->mRestrictionsLoaded;
2806         }
2807
2808         /**
2809          * Accessor/initialisation for mRestrictions
2810          *
2811          * @param string $action Action that permission needs to be checked for
2812          * @return array Restriction levels needed to take the action. All levels are
2813          *     required. Note that restriction levels are normally user rights, but 'sysop'
2814          *     and 'autoconfirmed' are also allowed for backwards compatibility. These should
2815          *     be mapped to 'editprotected' and 'editsemiprotected' respectively.
2816          */
2817         public function getRestrictions( $action ) {
2818                 if ( !$this->mRestrictionsLoaded ) {
2819                         $this->loadRestrictions();
2820                 }
2821                 return isset( $this->mRestrictions[$action] )
2822                                 ? $this->mRestrictions[$action]
2823                                 : array();
2824         }
2825
2826         /**
2827          * Accessor/initialisation for mRestrictions
2828          *
2829          * @return array Keys are actions, values are arrays as returned by
2830          *     Title::getRestrictions()
2831          * @since 1.23
2832          */
2833         public function getAllRestrictions() {
2834                 if ( !$this->mRestrictionsLoaded ) {
2835                         $this->loadRestrictions();
2836                 }
2837                 return $this->mRestrictions;
2838         }
2839
2840         /**
2841          * Get the expiry time for the restriction against a given action
2842          *
2843          * @param string $action
2844          * @return string|bool 14-char timestamp, or 'infinity' if the page is protected forever
2845          *     or not protected at all, or false if the action is not recognised.
2846          */
2847         public function getRestrictionExpiry( $action ) {
2848                 if ( !$this->mRestrictionsLoaded ) {
2849                         $this->loadRestrictions();
2850                 }
2851                 return isset( $this->mRestrictionsExpiry[$action] ) ? $this->mRestrictionsExpiry[$action] : false;
2852         }
2853
2854         /**
2855          * Returns cascading restrictions for the current article
2856          *
2857          * @return bool
2858          */
2859         function areRestrictionsCascading() {
2860                 if ( !$this->mRestrictionsLoaded ) {
2861                         $this->loadRestrictions();
2862                 }
2863
2864                 return $this->mCascadeRestriction;
2865         }
2866
2867         /**
2868          * Loads a string into mRestrictions array
2869          *
2870          * @param ResultWrapper $res Resource restrictions as an SQL result.
2871          * @param string $oldFashionedRestrictions Comma-separated list of page
2872          *        restrictions from page table (pre 1.10)
2873          */
2874         private function loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions = null ) {
2875                 $rows = array();
2876
2877                 foreach ( $res as $row ) {
2878                         $rows[] = $row;
2879                 }
2880
2881                 $this->loadRestrictionsFromRows( $rows, $oldFashionedRestrictions );
2882         }
2883
2884         /**
2885          * Compiles list of active page restrictions from both page table (pre 1.10)
2886          * and page_restrictions table for this existing page.
2887          * Public for usage by LiquidThreads.
2888          *
2889          * @param array $rows Array of db result objects
2890          * @param string $oldFashionedRestrictions Comma-separated list of page
2891          *   restrictions from page table (pre 1.10)
2892          */
2893         public function loadRestrictionsFromRows( $rows, $oldFashionedRestrictions = null ) {
2894                 global $wgContLang;
2895                 $dbr = wfGetDB( DB_SLAVE );
2896
2897                 $restrictionTypes = $this->getRestrictionTypes();
2898
2899                 foreach ( $restrictionTypes as $type ) {
2900                         $this->mRestrictions[$type] = array();
2901                         $this->mRestrictionsExpiry[$type] = $wgContLang->formatExpiry( '', TS_MW );
2902                 }
2903
2904                 $this->mCascadeRestriction = false;
2905
2906                 # Backwards-compatibility: also load the restrictions from the page record (old format).
2907
2908                 if ( $oldFashionedRestrictions === null ) {
2909                         $oldFashionedRestrictions = $dbr->selectField( 'page', 'page_restrictions',
2910                                 array( 'page_id' => $this->getArticleID() ), __METHOD__ );
2911                 }
2912
2913                 if ( $oldFashionedRestrictions != '' ) {
2914
2915                         foreach ( explode( ':', trim( $oldFashionedRestrictions ) ) as $restrict ) {
2916                                 $temp = explode( '=', trim( $restrict ) );
2917                                 if ( count( $temp ) == 1 ) {
2918                                         // old old format should be treated as edit/move restriction
2919                                         $this->mRestrictions['edit'] = explode( ',', trim( $temp[0] ) );
2920                                         $this->mRestrictions['move'] = explode( ',', trim( $temp[0] ) );
2921                                 } else {
2922                                         $restriction = trim( $temp[1] );
2923                                         if ( $restriction != '' ) { //some old entries are empty
2924                                                 $this->mRestrictions[$temp[0]] = explode( ',', $restriction );
2925                                         }
2926                                 }
2927                         }
2928
2929                         $this->mOldRestrictions = true;
2930
2931                 }
2932
2933                 if ( count( $rows ) ) {
2934                         # Current system - load second to make them override.
2935                         $now = wfTimestampNow();
2936                         $purgeExpired = false;
2937
2938                         # Cycle through all the restrictions.
2939                         foreach ( $rows as $row ) {
2940
2941                                 // Don't take care of restrictions types that aren't allowed
2942                                 if ( !in_array( $row->pr_type, $restrictionTypes ) ) {
2943                                         continue;
2944                                 }
2945
2946                                 // This code should be refactored, now that it's being used more generally,
2947                                 // But I don't really see any harm in leaving it in Block for now -werdna
2948                                 $expiry = $wgContLang->formatExpiry( $row->pr_expiry, TS_MW );
2949
2950                                 // Only apply the restrictions if they haven't expired!
2951                                 if ( !$expiry || $expiry > $now ) {
2952                                         $this->mRestrictionsExpiry[$row->pr_type] = $expiry;
2953                                         $this->mRestrictions[$row->pr_type] = explode( ',', trim( $row->pr_level ) );
2954
2955                                         $this->mCascadeRestriction |= $row->pr_cascade;
2956                                 } else {
2957                                         // Trigger a lazy purge of expired restrictions
2958                                         $purgeExpired = true;
2959                                 }
2960                         }
2961
2962                         if ( $purgeExpired ) {
2963                                 Title::purgeExpiredRestrictions();
2964                         }
2965                 }
2966
2967                 $this->mRestrictionsLoaded = true;
2968         }
2969
2970         /**
2971          * Load restrictions from the page_restrictions table
2972          *
2973          * @param string $oldFashionedRestrictions Comma-separated list of page
2974          *   restrictions from page table (pre 1.10)
2975          */
2976         public function loadRestrictions( $oldFashionedRestrictions = null ) {
2977                 global $wgContLang;
2978                 if ( !$this->mRestrictionsLoaded ) {
2979                         if ( $this->exists() ) {
2980                                 $dbr = wfGetDB( DB_SLAVE );
2981
2982                                 $res = $dbr->select(
2983                                         'page_restrictions',
2984                                         array( 'pr_type', 'pr_expiry', 'pr_level', 'pr_cascade' ),
2985                                         array( 'pr_page' => $this->getArticleID() ),
2986                                         __METHOD__
2987                                 );
2988
2989                                 $this->loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions );
2990                         } else {
2991                                 $title_protection = $this->getTitleProtection();
2992
2993                                 if ( $title_protection ) {
2994                                         $now = wfTimestampNow();
2995                                         $expiry = $wgContLang->formatExpiry( $title_protection['expiry'], TS_MW );
2996
2997                                         if ( !$expiry || $expiry > $now ) {
2998                                                 // Apply the restrictions
2999                                                 $this->mRestrictionsExpiry['create'] = $expiry;
3000                                                 $this->mRestrictions['create'] = explode( ',', trim( $title_protection['permission'] ) );
3001                                         } else { // Get rid of the old restrictions
3002                                                 Title::purgeExpiredRestrictions();
3003                                                 $this->mTitleProtection = false;
3004                                         }
3005                                 } else {
3006                                         $this->mRestrictionsExpiry['create'] = $wgContLang->formatExpiry( '', TS_MW );
3007                                 }
3008                                 $this->mRestrictionsLoaded = true;
3009                         }
3010                 }
3011         }
3012
3013         /**
3014          * Flush the protection cache in this object and force reload from the database.
3015          * This is used when updating protection from WikiPage::doUpdateRestrictions().
3016          */
3017         public function flushRestrictions() {
3018                 $this->mRestrictionsLoaded = false;
3019                 $this->mTitleProtection = null;
3020         }
3021
3022         /**
3023          * Purge expired restrictions from the page_restrictions table
3024          */
3025         static function purgeExpiredRestrictions() {
3026                 if ( wfReadOnly() ) {
3027                         return;
3028                 }
3029
3030                 $method = __METHOD__;
3031                 $dbw = wfGetDB( DB_MASTER );
3032                 $dbw->onTransactionIdle( function () use ( $dbw, $method ) {
3033                         $dbw->delete(
3034                                 'page_restrictions',
3035                                 array( 'pr_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ),
3036                                 $method
3037                         );
3038                         $dbw->delete(
3039                                 'protected_titles',
3040                                 array( 'pt_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ),
3041                                 $method
3042                         );
3043                 } );
3044         }
3045
3046         /**
3047          * Does this have subpages?  (Warning, usually requires an extra DB query.)
3048          *
3049          * @return bool
3050          */
3051         public function hasSubpages() {
3052                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
3053                         # Duh
3054                         return false;
3055                 }
3056
3057                 # We dynamically add a member variable for the purpose of this method
3058                 # alone to cache the result.  There's no point in having it hanging
3059                 # around uninitialized in every Title object; therefore we only add it
3060                 # if needed and don't declare it statically.
3061                 if ( $this->mHasSubpages === null ) {
3062                         $this->mHasSubpages = false;
3063                         $subpages = $this->getSubpages( 1 );
3064                         if ( $subpages instanceof TitleArray ) {
3065                                 $this->mHasSubpages = (bool)$subpages->count();
3066                         }
3067                 }
3068
3069                 return $this->mHasSubpages;
3070         }
3071
3072         /**
3073          * Get all subpages of this page.
3074          *
3075          * @param int $limit Maximum number of subpages to fetch; -1 for no limit
3076          * @return TitleArray|array TitleArray, or empty array if this page's namespace
3077          *  doesn't allow subpages
3078          */
3079         public function getSubpages( $limit = -1 ) {
3080                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3081                         return array();
3082                 }
3083
3084                 $dbr = wfGetDB( DB_SLAVE );
3085                 $conds['page_namespace'] = $this->getNamespace();
3086                 $conds[] = 'page_title ' . $dbr->buildLike( $this->getDBkey() . '/', $dbr->anyString() );
3087                 $options = array();
3088                 if ( $limit > -1 ) {
3089                         $options['LIMIT'] = $limit;
3090                 }
3091                 $this->mSubpages = TitleArray::newFromResult(
3092                         $dbr->select( 'page',
3093                                 array( 'page_id', 'page_namespace', 'page_title', 'page_is_redirect' ),
3094                                 $conds,
3095                                 __METHOD__,
3096                                 $options
3097                         )
3098                 );
3099                 return $this->mSubpages;
3100         }
3101
3102         /**
3103          * Is there a version of this page in the deletion archive?
3104          *
3105          * @return int The number of archived revisions
3106          */
3107         public function isDeleted() {
3108                 if ( $this->getNamespace() < 0 ) {
3109                         $n = 0;
3110                 } else {
3111                         $dbr = wfGetDB( DB_SLAVE );
3112
3113                         $n = $dbr->selectField( 'archive', 'COUNT(*)',
3114                                 array( 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ),
3115                                 __METHOD__
3116                         );
3117                         if ( $this->getNamespace() == NS_FILE ) {
3118                                 $n += $dbr->selectField( 'filearchive', 'COUNT(*)',
3119                                         array( 'fa_name' => $this->getDBkey() ),
3120                                         __METHOD__
3121                                 );
3122                         }
3123                 }
3124                 return (int)$n;
3125         }
3126
3127         /**
3128          * Is there a version of this page in the deletion archive?
3129          *
3130          * @return bool
3131          */
3132         public function isDeletedQuick() {
3133                 if ( $this->getNamespace() < 0 ) {
3134                         return false;
3135                 }
3136                 $dbr = wfGetDB( DB_SLAVE );
3137                 $deleted = (bool)$dbr->selectField( 'archive', '1',
3138                         array( 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ),
3139                         __METHOD__
3140                 );
3141                 if ( !$deleted && $this->getNamespace() == NS_FILE ) {
3142                         $deleted = (bool)$dbr->selectField( 'filearchive', '1',
3143                                 array( 'fa_name' => $this->getDBkey() ),
3144                                 __METHOD__
3145                         );
3146                 }
3147                 return $deleted;
3148         }
3149
3150         /**
3151          * Get the article ID for this Title from the link cache,
3152          * adding it if necessary
3153          *
3154          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select
3155          *  for update
3156          * @return int The ID
3157          */
3158         public function getArticleID( $flags = 0 ) {
3159                 if ( $this->getNamespace() < 0 ) {
3160                         $this->mArticleID = 0;
3161                         return $this->mArticleID;
3162                 }
3163                 $linkCache = LinkCache::singleton();
3164                 if ( $flags & self::GAID_FOR_UPDATE ) {
3165                         $oldUpdate = $linkCache->forUpdate( true );
3166                         $linkCache->clearLink( $this );
3167                         $this->mArticleID = $linkCache->addLinkObj( $this );
3168                         $linkCache->forUpdate( $oldUpdate );
3169                 } else {
3170                         if ( -1 == $this->mArticleID ) {
3171                                 $this->mArticleID = $linkCache->addLinkObj( $this );
3172                         }
3173                 }
3174                 return $this->mArticleID;
3175         }
3176
3177         /**
3178          * Is this an article that is a redirect page?
3179          * Uses link cache, adding it if necessary
3180          *
3181          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3182          * @return bool
3183          */
3184         public function isRedirect( $flags = 0 ) {
3185                 if ( !is_null( $this->mRedirect ) ) {
3186                         return $this->mRedirect;
3187                 }
3188                 # Calling getArticleID() loads the field from cache as needed
3189                 if ( !$this->getArticleID( $flags ) ) {
3190                         $this->mRedirect = false;
3191                         return $this->mRedirect;
3192                 }
3193
3194                 $linkCache = LinkCache::singleton();
3195                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'redirect' );
3196                 if ( $cached === null ) {
3197                         # Trust LinkCache's state over our own
3198                         # LinkCache is telling us that the page doesn't exist, despite there being cached
3199                         # data relating to an existing page in $this->mArticleID. Updaters should clear
3200                         # LinkCache as appropriate, or use $flags = Title::GAID_FOR_UPDATE. If that flag is
3201                         # set, then LinkCache will definitely be up to date here, since getArticleID() forces
3202                         # LinkCache to refresh its data from the master.
3203                         $this->mRedirect = false;
3204                         return $this->mRedirect;
3205                 }
3206
3207                 $this->mRedirect = (bool)$cached;
3208
3209                 return $this->mRedirect;
3210         }
3211
3212         /**
3213          * What is the length of this page?
3214          * Uses link cache, adding it if necessary
3215          *
3216          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3217          * @return int
3218          */
3219         public function getLength( $flags = 0 ) {
3220                 if ( $this->mLength != -1 ) {
3221                         return $this->mLength;
3222                 }
3223                 # Calling getArticleID() loads the field from cache as needed
3224                 if ( !$this->getArticleID( $flags ) ) {
3225                         $this->mLength = 0;
3226                         return $this->mLength;
3227                 }
3228                 $linkCache = LinkCache::singleton();
3229                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'length' );
3230                 if ( $cached === null ) {
3231                         # Trust LinkCache's state over our own, as for isRedirect()
3232                         $this->mLength = 0;
3233                         return $this->mLength;
3234                 }
3235
3236                 $this->mLength = intval( $cached );
3237
3238                 return $this->mLength;
3239         }
3240
3241         /**
3242          * What is the page_latest field for this page?
3243          *
3244          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3245          * @return int Int or 0 if the page doesn't exist
3246          */
3247         public function getLatestRevID( $flags = 0 ) {
3248                 if ( !( $flags & Title::GAID_FOR_UPDATE ) && $this->mLatestID !== false ) {
3249                         return intval( $this->mLatestID );
3250                 }
3251                 # Calling getArticleID() loads the field from cache as needed
3252                 if ( !$this->getArticleID( $flags ) ) {
3253                         $this->mLatestID = 0;
3254                         return $this->mLatestID;
3255                 }
3256                 $linkCache = LinkCache::singleton();
3257                 $linkCache->addLinkObj( $this );
3258                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'revision' );
3259                 if ( $cached === null ) {
3260                         # Trust LinkCache's state over our own, as for isRedirect()
3261                         $this->mLatestID = 0;
3262                         return $this->mLatestID;
3263                 }
3264
3265                 $this->mLatestID = intval( $cached );
3266
3267                 return $this->mLatestID;
3268         }
3269
3270         /**
3271          * This clears some fields in this object, and clears any associated
3272          * keys in the "bad links" section of the link cache.
3273          *
3274          * - This is called from WikiPage::doEdit() and WikiPage::insertOn() to allow
3275          * loading of the new page_id. It's also called from
3276          * WikiPage::doDeleteArticleReal()
3277          *
3278          * @param int $newid The new Article ID
3279          */
3280         public function resetArticleID( $newid ) {
3281                 $linkCache = LinkCache::singleton();
3282                 $linkCache->clearLink( $this );
3283
3284                 if ( $newid === false ) {
3285                         $this->mArticleID = -1;
3286                 } else {
3287                         $this->mArticleID = intval( $newid );
3288                 }
3289                 $this->mRestrictionsLoaded = false;
3290                 $this->mRestrictions = array();
3291                 $this->mRedirect = null;
3292                 $this->mLength = -1;
3293                 $this->mLatestID = false;
3294                 $this->mContentModel = false;
3295                 $this->mEstimateRevisions = null;
3296                 $this->mPageLanguage = false;
3297                 $this->mDbPageLanguage = null;
3298                 $this->mIsBigDeletion = null;
3299         }
3300
3301         /**
3302          * Capitalize a text string for a title if it belongs to a namespace that capitalizes
3303          *
3304          * @param string $text Containing title to capitalize
3305          * @param int $ns Namespace index, defaults to NS_MAIN
3306          * @return string Containing capitalized title
3307          */
3308         public static function capitalize( $text, $ns = NS_MAIN ) {
3309                 global $wgContLang;
3310
3311                 if ( MWNamespace::isCapitalized( $ns ) ) {
3312                         return $wgContLang->ucfirst( $text );
3313                 } else {
3314                         return $text;
3315                 }
3316         }
3317
3318         /**
3319          * Secure and split - main initialisation function for this object
3320          *
3321          * Assumes that mDbkeyform has been set, and is urldecoded
3322          * and uses underscores, but not otherwise munged.  This function
3323          * removes illegal characters, splits off the interwiki and
3324          * namespace prefixes, sets the other forms, and canonicalizes
3325          * everything.
3326          *
3327          * @return bool True on success
3328          */
3329         private function secureAndSplit() {
3330                 # Initialisation
3331                 $this->mInterwiki = '';
3332                 $this->mFragment = '';
3333                 $this->mNamespace = $this->mDefaultNamespace; # Usually NS_MAIN
3334
3335                 $dbkey = $this->mDbkeyform;
3336
3337                 try {
3338                         // @note: splitTitleString() is a temporary hack to allow MediaWikiTitleCodec to share
3339                         //        the parsing code with Title, while avoiding massive refactoring.
3340                         // @todo: get rid of secureAndSplit, refactor parsing code.
3341                         $titleParser = self::getTitleParser();
3342                         $parts = $titleParser->splitTitleString( $dbkey, $this->getDefaultNamespace() );
3343                 } catch ( MalformedTitleException $ex ) {
3344                         return false;
3345                 }
3346
3347                 # Fill fields
3348                 $this->setFragment( '#' . $parts['fragment'] );
3349                 $this->mInterwiki = $parts['interwiki'];
3350                 $this->mLocalInterwiki = $parts['local_interwiki'];
3351                 $this->mNamespace = $parts['namespace'];
3352                 $this->mUserCaseDBKey = $parts['user_case_dbkey'];
3353
3354                 $this->mDbkeyform = $parts['dbkey'];
3355                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
3356                 $this->mTextform = str_replace( '_', ' ', $this->mDbkeyform );
3357
3358                 # We already know that some pages won't be in the database!
3359                 if ( $this->isExternal() || $this->mNamespace == NS_SPECIAL ) {
3360                         $this->mArticleID = 0;
3361                 }
3362
3363                 return true;
3364         }
3365
3366         /**
3367          * Get an array of Title objects linking to this Title
3368          * Also stores the IDs in the link cache.
3369          *
3370          * WARNING: do not use this function on arbitrary user-supplied titles!
3371          * On heavily-used templates it will max out the memory.
3372          *
3373          * @param array $options May be FOR UPDATE
3374          * @param string $table Table name
3375          * @param string $prefix Fields prefix
3376          * @return Title[] Array of Title objects linking here
3377          */
3378         public function getLinksTo( $options = array(), $table = 'pagelinks', $prefix = 'pl' ) {
3379                 if ( count( $options ) > 0 ) {
3380                         $db = wfGetDB( DB_MASTER );
3381                 } else {
3382                         $db = wfGetDB( DB_SLAVE );
3383                 }
3384
3385                 $res = $db->select(
3386                         array( 'page', $table ),
3387                         self::getSelectFields(),
3388                         array(
3389                                 "{$prefix}_from=page_id",
3390                                 "{$prefix}_namespace" => $this->getNamespace(),
3391                                 "{$prefix}_title" => $this->getDBkey() ),
3392                         __METHOD__,
3393                         $options
3394                 );
3395
3396                 $retVal = array();
3397                 if ( $res->numRows() ) {
3398                         $linkCache = LinkCache::singleton();
3399                         foreach ( $res as $row ) {
3400                                 $titleObj = Title::makeTitle( $row->page_namespace, $row->page_title );
3401                                 if ( $titleObj ) {
3402                                         $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3403                                         $retVal[] = $titleObj;
3404                                 }
3405                         }
3406                 }
3407                 return $retVal;
3408         }
3409
3410         /**
3411          * Get an array of Title objects using this Title as a template
3412          * Also stores the IDs in the link cache.
3413          *
3414          * WARNING: do not use this function on arbitrary user-supplied titles!
3415          * On heavily-used templates it will max out the memory.
3416          *
3417          * @param array $options May be FOR UPDATE
3418          * @return Title[] Array of Title the Title objects linking here
3419          */
3420         public function getTemplateLinksTo( $options = array() ) {
3421                 return $this->getLinksTo( $options, 'templatelinks', 'tl' );
3422         }
3423
3424         /**
3425          * Get an array of Title objects linked from this Title
3426          * Also stores the IDs in the link cache.
3427          *
3428          * WARNING: do not use this function on arbitrary user-supplied titles!
3429          * On heavily-used templates it will max out the memory.
3430          *
3431          * @param array $options May be FOR UPDATE
3432          * @param string $table Table name
3433          * @param string $prefix Fields prefix
3434          * @return array Array of Title objects linking here
3435          */
3436         public function getLinksFrom( $options = array(), $table = 'pagelinks', $prefix = 'pl' ) {
3437                 global $wgContentHandlerUseDB;
3438
3439                 $id = $this->getArticleID();
3440
3441                 # If the page doesn't exist; there can't be any link from this page
3442                 if ( !$id ) {
3443                         return array();
3444                 }
3445
3446                 if ( count( $options ) > 0 ) {
3447                         $db = wfGetDB( DB_MASTER );
3448                 } else {
3449                         $db = wfGetDB( DB_SLAVE );
3450                 }
3451
3452                 $namespaceFiled = "{$prefix}_namespace";
3453                 $titleField = "{$prefix}_title";
3454
3455                 $fields = array(
3456                         $namespaceFiled,
3457                         $titleField,
3458                         'page_id',
3459                         'page_len',
3460                         'page_is_redirect',
3461                         'page_latest'
3462                 );
3463
3464                 if ( $wgContentHandlerUseDB ) {
3465                         $fields[] = 'page_content_model';
3466                 }
3467
3468                 $res = $db->select(
3469                         array( $table, 'page' ),
3470                         $fields,
3471                         array( "{$prefix}_from" => $id ),
3472                         __METHOD__,
3473                         $options,
3474                         array( 'page' => array(
3475                                 'LEFT JOIN',
3476                                 array( "page_namespace=$namespaceFiled", "page_title=$titleField" )
3477                         ) )
3478                 );
3479
3480                 $retVal = array();
3481                 if ( $res->numRows() ) {
3482                         $linkCache = LinkCache::singleton();
3483                         foreach ( $res as $row ) {
3484                                 $titleObj = Title::makeTitle( $row->$namespaceFiled, $row->$titleField );
3485                                 if ( $titleObj ) {
3486                                         if ( $row->page_id ) {
3487                                                 $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3488                                         } else {
3489                                                 $linkCache->addBadLinkObj( $titleObj );
3490                                         }
3491                                         $retVal[] = $titleObj;
3492                                 }
3493                         }
3494                 }
3495                 return $retVal;
3496         }
3497
3498         /**
3499          * Get an array of Title objects used on this Title as a template
3500          * Also stores the IDs in the link cache.
3501          *
3502          * WARNING: do not use this function on arbitrary user-supplied titles!
3503          * On heavily-used templates it will max out the memory.
3504          *
3505          * @param array $options May be FOR UPDATE
3506          * @return Title[] Array of Title the Title objects used here
3507          */
3508         public function getTemplateLinksFrom( $options = array() ) {
3509                 return $this->getLinksFrom( $options, 'templatelinks', 'tl' );
3510         }
3511
3512         /**
3513          * Get an array of Title objects referring to non-existent articles linked
3514          * from this page.
3515          *
3516          * @todo check if needed (used only in SpecialBrokenRedirects.php, and
3517          *   should use redirect table in this case).
3518          * @return Title[] Array of Title the Title objects
3519          */
3520         public function getBrokenLinksFrom() {
3521                 if ( $this->getArticleID() == 0 ) {
3522                         # All links from article ID 0 are false positives
3523                         return array();
3524                 }
3525
3526                 $dbr = wfGetDB( DB_SLAVE );
3527                 $res = $dbr->select(
3528                         array( 'page', 'pagelinks' ),
3529                         array( 'pl_namespace', 'pl_title' ),
3530                         array(
3531                                 'pl_from' => $this->getArticleID(),
3532                                 'page_namespace IS NULL'
3533                         ),
3534                         __METHOD__, array(),
3535                         array(
3536                                 'page' => array(
3537                                         'LEFT JOIN',
3538                                         array( 'pl_namespace=page_namespace', 'pl_title=page_title' )
3539                                 )
3540                         )
3541                 );
3542
3543                 $retVal = array();
3544                 foreach ( $res as $row ) {
3545                         $retVal[] = Title::makeTitle( $row->pl_namespace, $row->pl_title );
3546                 }
3547                 return $retVal;
3548         }
3549
3550         /**
3551          * Get a list of URLs to purge from the Squid cache when this
3552          * page changes
3553          *
3554          * @return string[] Array of String the URLs
3555          */
3556         public function getSquidURLs() {
3557                 $urls = array(
3558                         $this->getInternalURL(),
3559                         $this->getInternalURL( 'action=history' )
3560                 );
3561
3562                 $pageLang = $this->getPageLanguage();
3563                 if ( $pageLang->hasVariants() ) {
3564                         $variants = $pageLang->getVariants();
3565                         foreach ( $variants as $vCode ) {
3566                                 $urls[] = $this->getInternalURL( '', $vCode );
3567                         }
3568                 }
3569
3570                 // If we are looking at a css/js user subpage, purge the action=raw.
3571                 if ( $this->isJsSubpage() ) {
3572                         $urls[] = $this->getInternalUrl( 'action=raw&ctype=text/javascript' );
3573                 } elseif ( $this->isCssSubpage() ) {
3574                         $urls[] = $this->getInternalUrl( 'action=raw&ctype=text/css' );
3575                 }
3576
3577                 Hooks::run( 'TitleSquidURLs', array( $this, &$urls ) );
3578                 return $urls;
3579         }
3580
3581         /**
3582          * Purge all applicable Squid URLs
3583          */
3584         public function purgeSquid() {
3585                 global $wgUseSquid;
3586                 if ( $wgUseSquid ) {
3587                         $urls = $this->getSquidURLs();
3588                         $u = new SquidUpdate( $urls );
3589                         $u->doUpdate();
3590                 }
3591         }
3592
3593         /**
3594          * Move this page without authentication
3595          *
3596          * @deprecated since 1.25 use MovePage class instead
3597          * @param Title $nt The new page Title
3598          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3599          */
3600         public function moveNoAuth( &$nt ) {
3601                 wfDeprecated( __METHOD__, '1.25' );
3602                 return $this->moveTo( $nt, false );
3603         }
3604
3605         /**
3606          * Check whether a given move operation would be valid.
3607          * Returns true if ok, or a getUserPermissionsErrors()-like array otherwise
3608          *
3609          * @deprecated since 1.25, use MovePage's methods instead
3610          * @param Title $nt The new title
3611          * @param bool $auth Ignored
3612          * @param string $reason Is the log summary of the move, used for spam checking
3613          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3614          */
3615         public function isValidMoveOperation( &$nt, $auth = true, $reason = '' ) {
3616                 global $wgUser;
3617
3618                 if ( !( $nt instanceof Title ) ) {
3619                         // Normally we'd add this to $errors, but we'll get
3620                         // lots of syntax errors if $nt is not an object
3621                         return array( array( 'badtitletext' ) );
3622                 }
3623
3624                 $mp = new MovePage( $this, $nt );
3625                 $errors = wfMergeErrorArrays(
3626                         $mp->isValidMove()->getErrorsArray(),
3627                         $mp->checkPermissions( $wgUser, $reason )->getErrorsArray()
3628                 );
3629
3630                 return $errors ? : true;
3631         }
3632
3633         /**
3634          * Check if the requested move target is a valid file move target
3635          * @todo move this to MovePage
3636          * @param Title $nt Target title
3637          * @return array List of errors
3638          */
3639         protected function validateFileMoveOperation( $nt ) {
3640                 global $wgUser;
3641
3642                 $errors = array();
3643
3644                 $destFile = wfLocalFile( $nt );
3645                 if ( !$wgUser->isAllowed( 'reupload-shared' ) && !$destFile->exists() && wfFindFile( $nt ) ) {
3646                         $errors[] = array( 'file-exists-sharedrepo' );
3647                 }
3648
3649                 return $errors;
3650         }
3651
3652         /**
3653          * Move a title to a new location
3654          *
3655          * @deprecated since 1.25, use the MovePage class instead
3656          * @param Title $nt The new title
3657          * @param bool $auth Indicates whether $wgUser's permissions
3658          *  should be checked
3659          * @param string $reason The reason for the move
3660          * @param bool $createRedirect Whether to create a redirect from the old title to the new title.
3661          *  Ignored if the user doesn't have the suppressredirect right.
3662          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3663          */
3664         public function moveTo( &$nt, $auth = true, $reason = '', $createRedirect = true ) {
3665                 global $wgUser;
3666                 $err = $this->isValidMoveOperation( $nt, $auth, $reason );
3667                 if ( is_array( $err ) ) {
3668                         // Auto-block user's IP if the account was "hard" blocked
3669                         $wgUser->spreadAnyEditBlock();
3670                         return $err;
3671                 }
3672                 // Check suppressredirect permission
3673                 if ( $auth && !$wgUser->isAllowed( 'suppressredirect' ) ) {
3674                         $createRedirect = true;
3675                 }
3676
3677                 $mp = new MovePage( $this, $nt );
3678                 $status = $mp->move( $wgUser, $reason, $createRedirect );
3679                 if ( $status->isOK() ) {
3680                         return true;
3681                 } else {
3682                         return $status->getErrorsArray();
3683                 }
3684         }
3685
3686         /**
3687          * Move this page's subpages to be subpages of $nt
3688          *
3689          * @param Title $nt Move target
3690          * @param bool $auth Whether $wgUser's permissions should be checked
3691          * @param string $reason The reason for the move
3692          * @param bool $createRedirect Whether to create redirects from the old subpages to
3693          *     the new ones Ignored if the user doesn't have the 'suppressredirect' right
3694          * @return array Array with old page titles as keys, and strings (new page titles) or
3695          *     arrays (errors) as values, or an error array with numeric indices if no pages
3696          *     were moved
3697          */
3698         public function moveSubpages( $nt, $auth = true, $reason = '', $createRedirect = true ) {
3699                 global $wgMaximumMovedPages;
3700                 // Check permissions
3701                 if ( !$this->userCan( 'move-subpages' ) ) {
3702                         return array( 'cant-move-subpages' );
3703                 }
3704                 // Do the source and target namespaces support subpages?
3705                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3706                         return array( 'namespace-nosubpages',
3707                                 MWNamespace::getCanonicalName( $this->getNamespace() ) );
3708                 }
3709                 if ( !MWNamespace::hasSubpages( $nt->getNamespace() ) ) {
3710                         return array( 'namespace-nosubpages',
3711                                 MWNamespace::getCanonicalName( $nt->getNamespace() ) );
3712                 }
3713
3714                 $subpages = $this->getSubpages( $wgMaximumMovedPages + 1 );
3715                 $retval = array();
3716                 $count = 0;
3717                 foreach ( $subpages as $oldSubpage ) {
3718                         $count++;
3719                         if ( $count > $wgMaximumMovedPages ) {
3720                                 $retval[$oldSubpage->getPrefixedText()] =
3721                                                 array( 'movepage-max-pages',
3722                                                         $wgMaximumMovedPages );
3723                                 break;
3724                         }
3725
3726                         // We don't know whether this function was called before
3727                         // or after moving the root page, so check both
3728                         // $this and $nt
3729                         if ( $oldSubpage->getArticleID() == $this->getArticleID()
3730                                 || $oldSubpage->getArticleID() == $nt->getArticleID()
3731                         ) {
3732                                 // When moving a page to a subpage of itself,
3733                                 // don't move it twice
3734                                 continue;
3735                         }
3736                         $newPageName = preg_replace(
3737                                         '#^' . preg_quote( $this->getDBkey(), '#' ) . '#',
3738                                         StringUtils::escapeRegexReplacement( $nt->getDBkey() ), # bug 21234
3739                                         $oldSubpage->getDBkey() );
3740                         if ( $oldSubpage->isTalkPage() ) {
3741                                 $newNs = $nt->getTalkPage()->getNamespace();
3742                         } else {
3743                                 $newNs = $nt->getSubjectPage()->getNamespace();
3744                         }
3745                         # Bug 14385: we need makeTitleSafe because the new page names may
3746                         # be longer than 255 characters.
3747                         $newSubpage = Title::makeTitleSafe( $newNs, $newPageName );
3748
3749                         $success = $oldSubpage->moveTo( $newSubpage, $auth, $reason, $createRedirect );
3750                         if ( $success === true ) {
3751                                 $retval[$oldSubpage->getPrefixedText()] = $newSubpage->getPrefixedText();
3752                         } else {
3753                                 $retval[$oldSubpage->getPrefixedText()] = $success;
3754                         }
3755                 }
3756                 return $retval;
3757         }
3758
3759         /**
3760          * Checks if this page is just a one-rev redirect.
3761          * Adds lock, so don't use just for light purposes.
3762          *
3763          * @return bool
3764          */
3765         public function isSingleRevRedirect() {
3766                 global $wgContentHandlerUseDB;
3767
3768                 $dbw = wfGetDB( DB_MASTER );
3769
3770                 # Is it a redirect?
3771                 $fields = array( 'page_is_redirect', 'page_latest', 'page_id' );
3772                 if ( $wgContentHandlerUseDB ) {
3773                         $fields[] = 'page_content_model';
3774                 }
3775
3776                 $row = $dbw->selectRow( 'page',
3777                         $fields,
3778                         $this->pageCond(),
3779                         __METHOD__,
3780                         array( 'FOR UPDATE' )
3781                 );
3782                 # Cache some fields we may want
3783                 $this->mArticleID = $row ? intval( $row->page_id ) : 0;
3784                 $this->mRedirect = $row ? (bool)$row->page_is_redirect : false;
3785                 $this->mLatestID = $row ? intval( $row->page_latest ) : false;
3786                 $this->mContentModel = $row && isset( $row->page_content_model )
3787                         ? strval( $row->page_content_model )
3788                         : false;
3789
3790                 if ( !$this->mRedirect ) {
3791                         return false;
3792                 }
3793                 # Does the article have a history?
3794                 $row = $dbw->selectField( array( 'page', 'revision' ),
3795                         'rev_id',
3796                         array( 'page_namespace' => $this->getNamespace(),
3797                                 'page_title' => $this->getDBkey(),
3798                                 'page_id=rev_page',
3799                                 'page_latest != rev_id'
3800                         ),
3801                         __METHOD__,
3802                         array( 'FOR UPDATE' )
3803                 );
3804                 # Return true if there was no history
3805                 return ( $row === false );
3806         }
3807
3808         /**
3809          * Checks if $this can be moved to a given Title
3810          * - Selects for update, so don't call it unless you mean business
3811          *
3812          * @deprecated since 1.25, use MovePage's methods instead
3813          * @param Title $nt The new title to check
3814          * @return bool
3815          */
3816         public function isValidMoveTarget( $nt ) {
3817                 # Is it an existing file?
3818                 if ( $nt->getNamespace() == NS_FILE ) {
3819                         $file = wfLocalFile( $nt );
3820                         if ( $file->exists() ) {
3821                                 wfDebug( __METHOD__ . ": file exists\n" );
3822                                 return false;
3823                         }
3824                 }
3825                 # Is it a redirect with no history?
3826                 if ( !$nt->isSingleRevRedirect() ) {
3827                         wfDebug( __METHOD__ . ": not a one-rev redirect\n" );
3828                         return false;
3829                 }
3830                 # Get the article text
3831                 $rev = Revision::newFromTitle( $nt, false, Revision::READ_LATEST );
3832                 if ( !is_object( $rev ) ) {
3833                         return false;
3834                 }
3835                 $content = $rev->getContent();
3836                 # Does the redirect point to the source?
3837                 # Or is it a broken self-redirect, usually caused by namespace collisions?
3838                 $redirTitle = $content ? $content->getRedirectTarget() : null;
3839
3840                 if ( $redirTitle ) {
3841                         if ( $redirTitle->getPrefixedDBkey() != $this->getPrefixedDBkey() &&
3842                                 $redirTitle->getPrefixedDBkey() != $nt->getPrefixedDBkey() ) {
3843                                 wfDebug( __METHOD__ . ": redirect points to other page\n" );
3844                                 return false;
3845                         } else {
3846                                 return true;
3847                         }
3848                 } else {
3849                         # Fail safe (not a redirect after all. strange.)
3850                         wfDebug( __METHOD__ . ": failsafe: database sais " . $nt->getPrefixedDBkey() .
3851                                                 " is a redirect, but it doesn't contain a valid redirect.\n" );
3852                         return false;
3853                 }
3854         }
3855
3856         /**
3857          * Get categories to which this Title belongs and return an array of
3858          * categories' names.
3859          *
3860          * @return array Array of parents in the form:
3861          *        $parent => $currentarticle
3862          */
3863         public function getParentCategories() {
3864                 global $wgContLang;
3865
3866                 $data = array();
3867
3868                 $titleKey = $this->getArticleID();
3869
3870                 if ( $titleKey === 0 ) {
3871                         return $data;
3872                 }
3873
3874                 $dbr = wfGetDB( DB_SLAVE );
3875
3876                 $res = $dbr->select(
3877                         'categorylinks',
3878                         'cl_to',
3879                         array( 'cl_from' => $titleKey ),
3880                         __METHOD__
3881                 );
3882
3883                 if ( $res->numRows() > 0 ) {
3884                         foreach ( $res as $row ) {
3885                                 // $data[] = Title::newFromText($wgContLang->getNsText ( NS_CATEGORY ).':'.$row->cl_to);
3886                                 $data[$wgContLang->getNsText( NS_CATEGORY ) . ':' . $row->cl_to] = $this->getFullText();
3887                         }
3888                 }
3889                 return $data;
3890         }
3891
3892         /**
3893          * Get a tree of parent categories
3894          *
3895          * @param array $children Array with the children in the keys, to check for circular refs
3896          * @return array Tree of parent categories
3897          */
3898         public function getParentCategoryTree( $children = array() ) {
3899                 $stack = array();
3900                 $parents = $this->getParentCategories();
3901
3902                 if ( $parents ) {
3903                         foreach ( $parents as $parent => $current ) {
3904                                 if ( array_key_exists( $parent, $children ) ) {
3905                                         # Circular reference
3906                                         $stack[$parent] = array();
3907                                 } else {
3908                                         $nt = Title::newFromText( $parent );
3909                                         if ( $nt ) {
3910                                                 $stack[$parent] = $nt->getParentCategoryTree( $children + array( $parent => 1 ) );
3911                                         }
3912                                 }
3913                         }
3914                 }
3915
3916                 return $stack;
3917         }
3918
3919         /**
3920          * Get an associative array for selecting this title from
3921          * the "page" table
3922          *
3923          * @return array Array suitable for the $where parameter of DB::select()
3924          */
3925         public function pageCond() {
3926                 if ( $this->mArticleID > 0 ) {
3927                         // PK avoids secondary lookups in InnoDB, shouldn't hurt other DBs
3928                         return array( 'page_id' => $this->mArticleID );
3929                 } else {
3930                         return array( 'page_namespace' => $this->mNamespace, 'page_title' => $this->mDbkeyform );
3931                 }
3932         }
3933
3934         /**
3935          * Get the revision ID of the previous revision
3936          *
3937          * @param int $revId Revision ID. Get the revision that was before this one.
3938          * @param int $flags Title::GAID_FOR_UPDATE
3939          * @return int|bool Old revision ID, or false if none exists
3940          */
3941         public function getPreviousRevisionID( $revId, $flags = 0 ) {
3942                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
3943                 $revId = $db->selectField( 'revision', 'rev_id',
3944                         array(
3945                                 'rev_page' => $this->getArticleID( $flags ),
3946                                 'rev_id < ' . intval( $revId )
3947                         ),
3948                         __METHOD__,
3949                         array( 'ORDER BY' => 'rev_id DESC' )
3950                 );
3951
3952                 if ( $revId === false ) {
3953                         return false;
3954                 } else {
3955                         return intval( $revId );
3956                 }
3957         }
3958
3959         /**
3960          * Get the revision ID of the next revision
3961          *
3962          * @param int $revId Revision ID. Get the revision that was after this one.
3963          * @param int $flags Title::GAID_FOR_UPDATE
3964          * @return int|bool Next revision ID, or false if none exists
3965          */
3966         public function getNextRevisionID( $revId, $flags = 0 ) {
3967                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
3968                 $revId = $db->selectField( 'revision', 'rev_id',
3969                         array(
3970                                 'rev_page' => $this->getArticleID( $flags ),
3971                                 'rev_id > ' . intval( $revId )
3972                         ),
3973                         __METHOD__,
3974                         array( 'ORDER BY' => 'rev_id' )
3975                 );
3976
3977                 if ( $revId === false ) {
3978                         return false;
3979                 } else {
3980                         return intval( $revId );
3981                 }
3982         }
3983
3984         /**
3985          * Get the first revision of the page
3986          *
3987          * @param int $flags Title::GAID_FOR_UPDATE
3988          * @return Revision|null If page doesn't exist
3989          */
3990         public function getFirstRevision( $flags = 0 ) {
3991                 $pageId = $this->getArticleID( $flags );
3992                 if ( $pageId ) {
3993                         $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
3994                         $row = $db->selectRow( 'revision', Revision::selectFields(),
3995                                 array( 'rev_page' => $pageId ),
3996                                 __METHOD__,
3997                                 array( 'ORDER BY' => 'rev_timestamp ASC', 'LIMIT' => 1 )
3998                         );
3999                         if ( $row ) {
4000                                 return new Revision( $row );
4001                         }
4002                 }
4003                 return null;
4004         }
4005
4006         /**
4007          * Get the oldest revision timestamp of this page
4008          *
4009          * @param int $flags Title::GAID_FOR_UPDATE
4010          * @return string MW timestamp
4011          */
4012         public function getEarliestRevTime( $flags = 0 ) {
4013                 $rev = $this->getFirstRevision( $flags );
4014                 return $rev ? $rev->getTimestamp() : null;
4015         }
4016
4017         /**
4018          * Check if this is a new page
4019          *
4020          * @return bool
4021          */
4022         public function isNewPage() {
4023                 $dbr = wfGetDB( DB_SLAVE );
4024                 return (bool)$dbr->selectField( 'page', 'page_is_new', $this->pageCond(), __METHOD__ );
4025         }
4026
4027         /**
4028          * Check whether the number of revisions of this page surpasses $wgDeleteRevisionsLimit
4029          *
4030          * @return bool
4031          */
4032         public function isBigDeletion() {
4033                 global $wgDeleteRevisionsLimit;
4034
4035                 if ( !$wgDeleteRevisionsLimit ) {
4036                         return false;
4037                 }
4038
4039                 if ( $this->mIsBigDeletion === null ) {
4040                         $dbr = wfGetDB( DB_SLAVE );
4041
4042                         $revCount = $dbr->selectRowCount(
4043                                 'revision',
4044                                 '1',
4045                                 array( 'rev_page' => $this->getArticleID() ),
4046                                 __METHOD__,
4047                                 array( 'LIMIT' => $wgDeleteRevisionsLimit + 1 )
4048                         );
4049
4050                         $this->mIsBigDeletion = $revCount > $wgDeleteRevisionsLimit;
4051                 }
4052
4053                 return $this->mIsBigDeletion;
4054         }
4055
4056         /**
4057          * Get the approximate revision count of this page.
4058          *
4059          * @return int
4060          */
4061         public function estimateRevisionCount() {
4062                 if ( !$this->exists() ) {
4063                         return 0;
4064                 }
4065
4066                 if ( $this->mEstimateRevisions === null ) {
4067                         $dbr = wfGetDB( DB_SLAVE );
4068                         $this->mEstimateRevisions = $dbr->estimateRowCount( 'revision', '*',
4069                                 array( 'rev_page' => $this->getArticleID() ), __METHOD__ );
4070                 }
4071
4072                 return $this->mEstimateRevisions;
4073         }
4074
4075         /**
4076          * Get the number of revisions between the given revision.
4077          * Used for diffs and other things that really need it.
4078          *
4079          * @param int|Revision $old Old revision or rev ID (first before range)
4080          * @param int|Revision $new New revision or rev ID (first after range)
4081          * @param int|null $max Limit of Revisions to count, will be incremented to detect truncations
4082          * @return int Number of revisions between these revisions.
4083          */
4084         public function countRevisionsBetween( $old, $new, $max = null ) {
4085                 if ( !( $old instanceof Revision ) ) {
4086                         $old = Revision::newFromTitle( $this, (int)$old );
4087                 }
4088                 if ( !( $new instanceof Revision ) ) {
4089                         $new = Revision::newFromTitle( $this, (int)$new );
4090                 }
4091                 if ( !$old || !$new ) {
4092                         return 0; // nothing to compare
4093                 }
4094                 $dbr = wfGetDB( DB_SLAVE );
4095                 $conds = array(
4096                         'rev_page' => $this->getArticleID(),
4097                         'rev_timestamp > ' . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4098                         'rev_timestamp < ' . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4099                 );
4100                 if ( $max !== null ) {
4101                         $res = $dbr->select( 'revision', '1',
4102                                 $conds,
4103                                 __METHOD__,
4104                                 array( 'LIMIT' => $max + 1 ) // extra to detect truncation
4105                         );
4106                         return $res->numRows();
4107                 } else {
4108                         return (int)$dbr->selectField( 'revision', 'count(*)', $conds, __METHOD__ );
4109                 }
4110         }
4111
4112         /**
4113          * Get the authors between the given revisions or revision IDs.
4114          * Used for diffs and other things that really need it.
4115          *
4116          * @since 1.23
4117          *
4118          * @param int|Revision $old Old revision or rev ID (first before range by default)
4119          * @param int|Revision $new New revision or rev ID (first after range by default)
4120          * @param int $limit Maximum number of authors
4121          * @param string|array $options (Optional): Single option, or an array of options:
4122          *     'include_old' Include $old in the range; $new is excluded.
4123          *     'include_new' Include $new in the range; $old is excluded.
4124          *     'include_both' Include both $old and $new in the range.
4125          *     Unknown option values are ignored.
4126          * @return array|null Names of revision authors in the range; null if not both revisions exist
4127          */
4128         public function getAuthorsBetween( $old, $new, $limit, $options = array() ) {
4129                 if ( !( $old instanceof Revision ) ) {
4130                         $old = Revision::newFromTitle( $this, (int)$old );
4131                 }
4132                 if ( !( $new instanceof Revision ) ) {
4133                         $new = Revision::newFromTitle( $this, (int)$new );
4134                 }
4135                 // XXX: what if Revision objects are passed in, but they don't refer to this title?
4136                 // Add $old->getPage() != $new->getPage() || $old->getPage() != $this->getArticleID()
4137                 // in the sanity check below?
4138                 if ( !$old || !$new ) {
4139                         return null; // nothing to compare
4140                 }
4141                 $authors = array();
4142                 $old_cmp = '>';
4143                 $new_cmp = '<';
4144                 $options = (array)$options;
4145                 if ( in_array( 'include_old', $options ) ) {
4146                         $old_cmp = '>=';
4147                 }
4148                 if ( in_array( 'include_new', $options ) ) {
4149                         $new_cmp = '<=';
4150                 }
4151                 if ( in_array( 'include_both', $options ) ) {
4152                         $old_cmp = '>=';
4153                         $new_cmp = '<=';
4154                 }
4155                 // No DB query needed if $old and $new are the same or successive revisions:
4156                 if ( $old->getId() === $new->getId() ) {
4157                         return ( $old_cmp === '>' && $new_cmp === '<' ) ? array() : array( $old->getRawUserText() );
4158                 } elseif ( $old->getId() === $new->getParentId() ) {
4159                         if ( $old_cmp === '>=' && $new_cmp === '<=' ) {
4160                                 $authors[] = $old->getRawUserText();
4161                                 if ( $old->getRawUserText() != $new->getRawUserText() ) {
4162                                         $authors[] = $new->getRawUserText();
4163                                 }
4164                         } elseif ( $old_cmp === '>=' ) {
4165                                 $authors[] = $old->getRawUserText();
4166                         } elseif ( $new_cmp === '<=' ) {
4167                                 $authors[] = $new->getRawUserText();
4168                         }
4169                         return $authors;
4170                 }
4171                 $dbr = wfGetDB( DB_SLAVE );
4172                 $res = $dbr->select( 'revision', 'DISTINCT rev_user_text',
4173                         array(
4174                                 'rev_page' => $this->getArticleID(),
4175                                 "rev_timestamp $old_cmp " . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4176                                 "rev_timestamp $new_cmp " . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4177                         ), __METHOD__,
4178                         array( 'LIMIT' => $limit + 1 ) // add one so caller knows it was truncated
4179                 );
4180                 foreach ( $res as $row ) {
4181                         $authors[] = $row->rev_user_text;
4182                 }
4183                 return $authors;
4184         }
4185
4186         /**
4187          * Get the number of authors between the given revisions or revision IDs.
4188          * Used for diffs and other things that really need it.
4189          *
4190          * @param int|Revision $old Old revision or rev ID (first before range by default)
4191          * @param int|Revision $new New revision or rev ID (first after range by default)
4192          * @param int $limit Maximum number of authors
4193          * @param string|array $options (Optional): Single option, or an array of options:
4194          *     'include_old' Include $old in the range; $new is excluded.
4195          *     'include_new' Include $new in the range; $old is excluded.
4196          *     'include_both' Include both $old and $new in the range.
4197          *     Unknown option values are ignored.
4198          * @return int Number of revision authors in the range; zero if not both revisions exist
4199          */
4200         public function countAuthorsBetween( $old, $new, $limit, $options = array() ) {
4201                 $authors = $this->getAuthorsBetween( $old, $new, $limit, $options );
4202                 return $authors ? count( $authors ) : 0;
4203         }
4204
4205         /**
4206          * Compare with another title.
4207          *
4208          * @param Title $title
4209          * @return bool
4210          */
4211         public function equals( Title $title ) {
4212                 // Note: === is necessary for proper matching of number-like titles.
4213                 return $this->getInterwiki() === $title->getInterwiki()
4214                         && $this->getNamespace() == $title->getNamespace()
4215                         && $this->getDBkey() === $title->getDBkey();
4216         }
4217
4218         /**
4219          * Check if this title is a subpage of another title
4220          *
4221          * @param Title $title
4222          * @return bool
4223          */
4224         public function isSubpageOf( Title $title ) {
4225                 return $this->getInterwiki() === $title->getInterwiki()
4226                         && $this->getNamespace() == $title->getNamespace()
4227                         && strpos( $this->getDBkey(), $title->getDBkey() . '/' ) === 0;
4228         }
4229
4230         /**
4231          * Check if page exists.  For historical reasons, this function simply
4232          * checks for the existence of the title in the page table, and will
4233          * thus return false for interwiki links, special pages and the like.
4234          * If you want to know if a title can be meaningfully viewed, you should
4235          * probably call the isKnown() method instead.
4236          *
4237          * @return bool
4238          */
4239         public function exists() {
4240                 $exists = $this->getArticleID() != 0;
4241                 Hooks::run( 'TitleExists', array( $this, &$exists ) );
4242                 return $exists;
4243         }
4244
4245         /**
4246          * Should links to this title be shown as potentially viewable (i.e. as
4247          * "bluelinks"), even if there's no record by this title in the page
4248          * table?
4249          *
4250          * This function is semi-deprecated for public use, as well as somewhat
4251          * misleadingly named.  You probably just want to call isKnown(), which
4252          * calls this function internally.
4253          *
4254          * (ISSUE: Most of these checks are cheap, but the file existence check
4255          * can potentially be quite expensive.  Including it here fixes a lot of
4256          * existing code, but we might want to add an optional parameter to skip
4257          * it and any other expensive checks.)
4258          *
4259          * @return bool
4260          */
4261         public function isAlwaysKnown() {
4262                 $isKnown = null;
4263
4264                 /**
4265                  * Allows overriding default behavior for determining if a page exists.
4266                  * If $isKnown is kept as null, regular checks happen. If it's
4267                  * a boolean, this value is returned by the isKnown method.
4268                  *
4269                  * @since 1.20
4270                  *
4271                  * @param Title $title
4272                  * @param bool|null $isKnown
4273                  */
4274                 Hooks::run( 'TitleIsAlwaysKnown', array( $this, &$isKnown ) );
4275
4276                 if ( !is_null( $isKnown ) ) {
4277                         return $isKnown;
4278                 }
4279
4280                 if ( $this->isExternal() ) {
4281                         return true;  // any interwiki link might be viewable, for all we know
4282                 }
4283
4284                 switch ( $this->mNamespace ) {
4285                         case NS_MEDIA:
4286                         case NS_FILE:
4287                                 // file exists, possibly in a foreign repo
4288                                 return (bool)wfFindFile( $this );
4289                         case NS_SPECIAL:
4290                                 // valid special page
4291                                 return SpecialPageFactory::exists( $this->getDBkey() );
4292                         case NS_MAIN:
4293                                 // selflink, possibly with fragment
4294                                 return $this->mDbkeyform == '';
4295                         case NS_MEDIAWIKI:
4296                                 // known system message
4297                                 return $this->hasSourceText() !== false;
4298                         default:
4299                                 return false;
4300                 }
4301         }
4302
4303         /**
4304          * Does this title refer to a page that can (or might) be meaningfully
4305          * viewed?  In particular, this function may be used to determine if
4306          * links to the title should be rendered as "bluelinks" (as opposed to
4307          * "redlinks" to non-existent pages).
4308          * Adding something else to this function will cause inconsistency
4309          * since LinkHolderArray calls isAlwaysKnown() and does its own
4310          * page existence check.
4311          *
4312          * @return bool
4313          */
4314         public function isKnown() {
4315                 return $this->isAlwaysKnown() || $this->exists();
4316         }
4317
4318         /**
4319          * Does this page have source text?
4320          *
4321          * @return bool
4322          */
4323         public function hasSourceText() {
4324                 if ( $this->exists() ) {
4325                         return true;
4326                 }
4327
4328                 if ( $this->mNamespace == NS_MEDIAWIKI ) {
4329                         // If the page doesn't exist but is a known system message, default
4330                         // message content will be displayed, same for language subpages-
4331                         // Use always content language to avoid loading hundreds of languages
4332                         // to get the link color.
4333                         global $wgContLang;
4334                         list( $name, ) = MessageCache::singleton()->figureMessage(
4335                                 $wgContLang->lcfirst( $this->getText() )
4336                         );
4337                         $message = wfMessage( $name )->inLanguage( $wgContLang )->useDatabase( false );
4338                         return $message->exists();
4339                 }
4340
4341                 return false;
4342         }
4343
4344         /**
4345          * Get the default message text or false if the message doesn't exist
4346          *
4347          * @return string|bool
4348          */
4349         public function getDefaultMessageText() {
4350                 global $wgContLang;
4351
4352                 if ( $this->getNamespace() != NS_MEDIAWIKI ) { // Just in case
4353                         return false;
4354                 }
4355
4356                 list( $name, $lang ) = MessageCache::singleton()->figureMessage(
4357                         $wgContLang->lcfirst( $this->getText() )
4358                 );
4359                 $message = wfMessage( $name )->inLanguage( $lang )->useDatabase( false );
4360
4361                 if ( $message->exists() ) {
4362                         return $message->plain();
4363                 } else {
4364                         return false;
4365                 }
4366         }
4367
4368         /**
4369          * Updates page_touched for this page; called from LinksUpdate.php
4370          *
4371          * @return bool True if the update succeeded
4372          */
4373         public function invalidateCache() {
4374                 if ( wfReadOnly() ) {
4375                         return false;
4376                 }
4377
4378                 if ( $this->mArticleID === 0 ) {
4379                         return true; // avoid gap locking if we know it's not there
4380                 }
4381
4382                 $method = __METHOD__;
4383                 $dbw = wfGetDB( DB_MASTER );
4384                 $conds = $this->pageCond();
4385                 $dbw->onTransactionIdle( function () use ( $dbw, $conds, $method ) {
4386                         $dbw->update(
4387                                 'page',
4388                                 array( 'page_touched' => $dbw->timestamp() ),
4389                                 $conds,
4390                                 $method
4391                         );
4392                 } );
4393
4394                 return true;
4395         }
4396
4397         /**
4398          * Update page_touched timestamps and send squid purge messages for
4399          * pages linking to this title. May be sent to the job queue depending
4400          * on the number of links. Typically called on create and delete.
4401          */
4402         public function touchLinks() {
4403                 $u = new HTMLCacheUpdate( $this, 'pagelinks' );
4404                 $u->doUpdate();
4405
4406                 if ( $this->getNamespace() == NS_CATEGORY ) {
4407                         $u = new HTMLCacheUpdate( $this, 'categorylinks' );
4408                         $u->doUpdate();
4409                 }
4410         }
4411
4412         /**
4413          * Get the last touched timestamp
4414          *
4415          * @param DatabaseBase $db Optional db
4416          * @return string Last-touched timestamp
4417          */
4418         public function getTouched( $db = null ) {
4419                 if ( $db === null ) {
4420                         $db = wfGetDB( DB_SLAVE );
4421                 }
4422                 $touched = $db->selectField( 'page', 'page_touched', $this->pageCond(), __METHOD__ );
4423                 return $touched;
4424         }
4425
4426         /**
4427          * Get the timestamp when this page was updated since the user last saw it.
4428          *
4429          * @param User $user
4430          * @return string|null
4431          */
4432         public function getNotificationTimestamp( $user = null ) {
4433                 global $wgUser, $wgShowUpdatedMarker;
4434                 // Assume current user if none given
4435                 if ( !$user ) {
4436                         $user = $wgUser;
4437                 }
4438                 // Check cache first
4439                 $uid = $user->getId();
4440                 // avoid isset here, as it'll return false for null entries
4441                 if ( array_key_exists( $uid, $this->mNotificationTimestamp ) ) {
4442                         return $this->mNotificationTimestamp[$uid];
4443                 }
4444                 if ( !$uid || !$wgShowUpdatedMarker || !$user->isAllowed( 'viewmywatchlist' ) ) {
4445                         $this->mNotificationTimestamp[$uid] = false;
4446                         return $this->mNotificationTimestamp[$uid];
4447                 }
4448                 // Don't cache too much!
4449                 if ( count( $this->mNotificationTimestamp ) >= self::CACHE_MAX ) {
4450                         $this->mNotificationTimestamp = array();
4451                 }
4452                 $dbr = wfGetDB( DB_SLAVE );
4453                 $this->mNotificationTimestamp[$uid] = $dbr->selectField( 'watchlist',
4454                         'wl_notificationtimestamp',
4455                         array(
4456                                 'wl_user' => $user->getId(),
4457                                 'wl_namespace' => $this->getNamespace(),
4458                                 'wl_title' => $this->getDBkey(),
4459                         ),
4460                         __METHOD__
4461                 );
4462                 return $this->mNotificationTimestamp[$uid];
4463         }
4464
4465         /**
4466          * Generate strings used for xml 'id' names in monobook tabs
4467          *
4468          * @param string $prepend Defaults to 'nstab-'
4469          * @return string XML 'id' name
4470          */
4471         public function getNamespaceKey( $prepend = 'nstab-' ) {
4472                 global $wgContLang;
4473                 // Gets the subject namespace if this title
4474                 $namespace = MWNamespace::getSubject( $this->getNamespace() );
4475                 // Checks if canonical namespace name exists for namespace
4476                 if ( MWNamespace::exists( $this->getNamespace() ) ) {
4477                         // Uses canonical namespace name
4478                         $namespaceKey = MWNamespace::getCanonicalName( $namespace );
4479                 } else {
4480                         // Uses text of namespace
4481                         $namespaceKey = $this->getSubjectNsText();
4482                 }
4483                 // Makes namespace key lowercase
4484                 $namespaceKey = $wgContLang->lc( $namespaceKey );
4485                 // Uses main
4486                 if ( $namespaceKey == '' ) {
4487                         $namespaceKey = 'main';
4488                 }
4489                 // Changes file to image for backwards compatibility
4490                 if ( $namespaceKey == 'file' ) {
4491                         $namespaceKey = 'image';
4492                 }
4493                 return $prepend . $namespaceKey;
4494         }
4495
4496         /**
4497          * Get all extant redirects to this Title
4498          *
4499          * @param int|null $ns Single namespace to consider; null to consider all namespaces
4500          * @return Title[] Array of Title redirects to this title
4501          */
4502         public function getRedirectsHere( $ns = null ) {
4503                 $redirs = array();
4504
4505                 $dbr = wfGetDB( DB_SLAVE );
4506                 $where = array(
4507                         'rd_namespace' => $this->getNamespace(),
4508                         'rd_title' => $this->getDBkey(),
4509                         'rd_from = page_id'
4510                 );
4511                 if ( $this->isExternal() ) {
4512                         $where['rd_interwiki'] = $this->getInterwiki();
4513                 } else {
4514                         $where[] = 'rd_interwiki = ' . $dbr->addQuotes( '' ) . ' OR rd_interwiki IS NULL';
4515                 }
4516                 if ( !is_null( $ns ) ) {
4517                         $where['page_namespace'] = $ns;
4518                 }
4519
4520                 $res = $dbr->select(
4521                         array( 'redirect', 'page' ),
4522                         array( 'page_namespace', 'page_title' ),
4523                         $where,
4524                         __METHOD__
4525                 );
4526
4527                 foreach ( $res as $row ) {
4528                         $redirs[] = self::newFromRow( $row );
4529                 }
4530                 return $redirs;
4531         }
4532
4533         /**
4534          * Check if this Title is a valid redirect target
4535          *
4536          * @return bool
4537          */
4538         public function isValidRedirectTarget() {
4539                 global $wgInvalidRedirectTargets;
4540
4541                 // invalid redirect targets are stored in a global array, but explicitly disallow Userlogout here
4542                 if ( $this->isSpecial( 'Userlogout' ) ) {
4543                         return false;
4544                 }
4545
4546                 foreach ( $wgInvalidRedirectTargets as $target ) {
4547                         if ( $this->isSpecial( $target ) ) {
4548                                 return false;
4549                         }
4550                 }
4551
4552                 return true;
4553         }
4554
4555         /**
4556          * Get a backlink cache object
4557          *
4558          * @return BacklinkCache
4559          */
4560         public function getBacklinkCache() {
4561                 return BacklinkCache::get( $this );
4562         }
4563
4564         /**
4565          * Whether the magic words __INDEX__ and __NOINDEX__ function for  this page.
4566          *
4567          * @return bool
4568          */
4569         public function canUseNoindex() {
4570                 global $wgContentNamespaces, $wgExemptFromUserRobotsControl;
4571
4572                 $bannedNamespaces = is_null( $wgExemptFromUserRobotsControl )
4573                         ? $wgContentNamespaces
4574                         : $wgExemptFromUserRobotsControl;
4575
4576                 return !in_array( $this->mNamespace, $bannedNamespaces );
4577
4578         }
4579
4580         /**
4581          * Returns the raw sort key to be used for categories, with the specified
4582          * prefix.  This will be fed to Collation::getSortKey() to get a
4583          * binary sortkey that can be used for actual sorting.
4584          *
4585          * @param string $prefix The prefix to be used, specified using
4586          *   {{defaultsort:}} or like [[Category:Foo|prefix]].  Empty for no
4587          *   prefix.
4588          * @return string
4589          */
4590         public function getCategorySortkey( $prefix = '' ) {
4591                 $unprefixed = $this->getText();
4592
4593                 // Anything that uses this hook should only depend
4594                 // on the Title object passed in, and should probably
4595                 // tell the users to run updateCollations.php --force
4596                 // in order to re-sort existing category relations.
4597                 Hooks::run( 'GetDefaultSortkey', array( $this, &$unprefixed ) );
4598                 if ( $prefix !== '' ) {
4599                         # Separate with a line feed, so the unprefixed part is only used as
4600                         # a tiebreaker when two pages have the exact same prefix.
4601                         # In UCA, tab is the only character that can sort above LF
4602                         # so we strip both of them from the original prefix.
4603                         $prefix = strtr( $prefix, "\n\t", '  ' );
4604                         return "$prefix\n$unprefixed";
4605                 }
4606                 return $unprefixed;
4607         }
4608
4609         /**
4610          * Get the language in which the content of this page is written in
4611          * wikitext. Defaults to $wgContLang, but in certain cases it can be
4612          * e.g. $wgLang (such as special pages, which are in the user language).
4613          *
4614          * @since 1.18
4615          * @return Language
4616          */
4617         public function getPageLanguage() {
4618                 global $wgLang, $wgLanguageCode;
4619                 if ( $this->isSpecialPage() ) {
4620                         // special pages are in the user language
4621                         return $wgLang;
4622                 }
4623
4624                 // Checking if DB language is set
4625                 if ( $this->mDbPageLanguage ) {
4626                         return wfGetLangObj( $this->mDbPageLanguage );
4627                 }
4628
4629                 if ( !$this->mPageLanguage || $this->mPageLanguage[1] !== $wgLanguageCode ) {
4630                         // Note that this may depend on user settings, so the cache should
4631                         // be only per-request.
4632                         // NOTE: ContentHandler::getPageLanguage() may need to load the
4633                         // content to determine the page language!
4634                         // Checking $wgLanguageCode hasn't changed for the benefit of unit
4635                         // tests.
4636                         $contentHandler = ContentHandler::getForTitle( $this );
4637                         $langObj = wfGetLangObj( $contentHandler->getPageLanguage( $this ) );
4638                         $this->mPageLanguage = array( $langObj->getCode(), $wgLanguageCode );
4639                 } else {
4640                         $langObj = wfGetLangObj( $this->mPageLanguage[0] );
4641                 }
4642
4643                 return $langObj;
4644         }
4645
4646         /**
4647          * Get the language in which the content of this page is written when
4648          * viewed by user. Defaults to $wgContLang, but in certain cases it can be
4649          * e.g. $wgLang (such as special pages, which are in the user language).
4650          *
4651          * @since 1.20
4652          * @return Language
4653          */
4654         public function getPageViewLanguage() {
4655                 global $wgLang;
4656
4657                 if ( $this->isSpecialPage() ) {
4658                         // If the user chooses a variant, the content is actually
4659                         // in a language whose code is the variant code.
4660                         $variant = $wgLang->getPreferredVariant();
4661                         if ( $wgLang->getCode() !== $variant ) {
4662                                 return Language::factory( $variant );
4663                         }
4664
4665                         return $wgLang;
4666                 }
4667
4668                 // @note Can't be cached persistently, depends on user settings.
4669                 // @note ContentHandler::getPageViewLanguage() may need to load the
4670                 //   content to determine the page language!
4671                 $contentHandler = ContentHandler::getForTitle( $this );
4672                 $pageLang = $contentHandler->getPageViewLanguage( $this );
4673                 return $pageLang;
4674         }
4675
4676         /**
4677          * Get a list of rendered edit notices for this page.
4678          *
4679          * Array is keyed by the original message key, and values are rendered using parseAsBlock, so
4680          * they will already be wrapped in paragraphs.
4681          *
4682          * @since 1.21
4683          * @param int $oldid Revision ID that's being edited
4684          * @return array
4685          */
4686         public function getEditNotices( $oldid = 0 ) {
4687                 $notices = array();
4688
4689                 # Optional notices on a per-namespace and per-page basis
4690                 $editnotice_ns = 'editnotice-' . $this->getNamespace();
4691                 $editnotice_ns_message = wfMessage( $editnotice_ns );
4692                 if ( $editnotice_ns_message->exists() ) {
4693                         $notices[$editnotice_ns] = '<div class="mw-editnotice mw-editnotice-namespace ' .
4694                                 Sanitizer::escapeClass( "mw-$editnotice_ns" ) . '">' .
4695                                 $editnotice_ns_message->parseAsBlock() . '</div>';
4696                 }
4697                 if ( MWNamespace::hasSubpages( $this->getNamespace() ) ) {
4698                         $parts = explode( '/', $this->getDBkey() );
4699                         $editnotice_base = $editnotice_ns;
4700                         while ( count( $parts ) > 0 ) {
4701                                 $editnotice_base .= '-' . array_shift( $parts );
4702                                 $editnotice_base_msg = wfMessage( $editnotice_base );
4703                                 if ( $editnotice_base_msg->exists() ) {
4704                                         $notices[$editnotice_base] = '<div class="mw-editnotice mw-editnotice-base ' .
4705                                                 Sanitizer::escapeClass( "mw-$editnotice_base" ) . '">' .
4706                                                 $editnotice_base_msg->parseAsBlock() . '</div>';
4707                                 }
4708                         }
4709                 } else {
4710                         # Even if there are no subpages in namespace, we still don't want / in MW ns.
4711                         $editnoticeText = $editnotice_ns . '-' . str_replace( '/', '-', $this->getDBkey() );
4712                         $editnoticeMsg = wfMessage( $editnoticeText );
4713                         if ( $editnoticeMsg->exists() ) {
4714                                 $notices[$editnoticeText] = '<div class="mw-editnotice mw-editnotice-page ' .
4715                                         Sanitizer::escapeClass( "mw-$editnoticeText" ) . '">' .
4716                                         $editnoticeMsg->parseAsBlock() . '</div>';
4717                         }
4718                 }
4719
4720                 Hooks::run( 'TitleGetEditNotices', array( $this, $oldid, &$notices ) );
4721                 return $notices;
4722         }
4723 }